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Sample records for depositional environments vary

  1. Can bed load transport drive varying depositional behaviour in river delta environments?

    Science.gov (United States)

    van der Vegt, H.; Storms, J. E. A.; Walstra, D. J. R.; Howes, N. C.

    2016-11-01

    Understanding the processes and conditions at the time of deposition is key to the development of robust geological models which adequately approximate the heterogeneous delta morphology and stratigraphy they represent. We show how the mechanism of sediment transport (the proportion of the sediment supply transported as bed load vs. suspended load) impacts channel kinematics, delta morphology and stratigraphy, to at least the same extent as the proportion of cohesive sediment supply. This finding is derived from 15 synthetic delta analogues generated by processes-based simulations in Delft3D. The model parameter space varies sediment transport mechanism against proportions of cohesive sediment whilst keeping the total sediment mass input constant. Proximal morphology and kinematics previously associated with sediment cohesivity are also produced by decreasing the proportion of bed load sediment transport. However, distal depositional patterns are different for changes in sediment transport and sediment load cohesivity. Changes in sediment transport mechanisms are also shown to impact clinoform geometry as well as the spatiotemporal scale of autogenic reorganisation through channel avulsions. We conclude that improving insight into the ratio of bed load to suspended load is crucial to predicting the geometric evolution of a delta.

  2. Contemporary depositional environments of the Omo delta.

    Science.gov (United States)

    Butzer, K W

    1970-05-02

    Geomorphological and sedimentological studies of depositional environments of the modern Omo River delta and floodplain are essential to an understanding of the Pliocene to Pleistocene Mursi, Nkalabong and Kibish Formations of the Lower Omo Basin (southwestern Ethiopia).

  3. Flexible Foraging of Ants under Unsteadily Varying Environment

    Science.gov (United States)

    Tao, Tomomi; Nakagawa, Hiroyuki; Yamasaki, Masato; Nishimori, Hiraku

    2004-08-01

    Using a simple model for the trail formation of ants, the relation between i) the schedule of feeding which represents the unsteady natural environment, ii) emerging patterns of trails connecting a nest with food resources, and iii) the foraging efficiency is studied. Simulations and a simple analysis show that the emergent trail pattern flexibly varies depending on the feeding schedule by which ants can make an efficient foraging according to the underlying unsteady environment.

  4. Budgerigar flight in a varying environment: flight at distinct speeds?

    Science.gov (United States)

    Schiffner, Ingo; Srinivasan, Mandyam V

    2016-06-01

    How do flying birds respond to changing environments? The behaviour of budgerigars, Melopsittacus undulatus, was filmed as they flew through a tapered tunnel. Unlike flying insects-which vary their speed progressively and continuously by holding constant the optic flow induced by the walls-the birds showed a tendency to fly at only two distinct, fixed speeds. They switched between a high speed in the wider section of the tunnel, and a low speed in the narrower section. The transition between the two speeds was abrupt, and anticipatory. The high speed was close to the energy-efficient, outdoor cruising speed for these birds, while the low speed was approximately half this value. This is the first observation of the existence of two distinct, preferred flight speeds in birds. A dual-speed flight strategy may be beneficial for birds that fly in varying environments, with the high speed set at an energy-efficient value for flight through open spaces, and the low speed suited to safe manoeuvring in a cluttered environment. The constancy of flight speed within each regime enables the distances of obstacles and landmarks to be directly calibrated in terms of optic flow, thus facilitating simple and efficient guidance of flight through changing environments.

  5. Study of selected phenotype switching strategies in time varying environment

    Energy Technology Data Exchange (ETDEWEB)

    Horvath, Denis, E-mail: horvath.denis@gmail.com [Centre of Interdisciplinary Biosciences, Institute of Physics, Faculty of Science, P.J. Šafárik University in Košice, Jesenná 5, 040 01 Košice (Slovakia); Brutovsky, Branislav, E-mail: branislav.brutovsky@upjs.sk [Department of Biophysics, Institute of Physics, P.J. Šafárik University in Košice, Jesenná 5, 040 01 Košice (Slovakia)

    2016-03-22

    Population heterogeneity plays an important role across many research, as well as the real-world, problems. The population heterogeneity relates to the ability of a population to cope with an environment change (or uncertainty) preventing its extinction. However, this ability is not always desirable as can be exemplified by an intratumor heterogeneity which positively correlates with the development of resistance to therapy. Causation of population heterogeneity is therefore in biology and medicine an intensively studied topic. In this paper the evolution of a specific strategy of population diversification, the phenotype switching, is studied at a conceptual level. The presented simulation model studies evolution of a large population of asexual organisms in a time-varying environment represented by a stochastic Markov process. Each organism disposes with a stochastic or nonlinear deterministic switching strategy realized by discrete-time models with evolvable parameters. We demonstrate that under rapidly varying exogenous conditions organisms operate in the vicinity of the bet-hedging strategy, while the deterministic patterns become relevant as the environmental variations are less frequent. Statistical characterization of the steady state regimes of the populations is done using the Hellinger and Kullback–Leibler functional distances and the Hamming distance. - Highlights: • Relation between phenotype switching and environment is studied. • The Markov chain Monte Carlo based model is developed. • Stochastic and deterministic strategies of phenotype switching are utilized. • Statistical measures of the dynamic heterogeneity reveal universal properties. • The results extend to higher lattice dimensions.

  6. Etiology of phenotype switching strategy in time varying stochastic environment

    Science.gov (United States)

    Horvath, Denis; Brutovsky, Branislav

    2016-11-01

    In the paper, we present the two-state discrete-time Markovian model to study the impact of the two alternative switching strategies on the fitness of the population evolving in time varying environment. The first strategy, referred as the 'responsive switching', enables the cell to make transition into the state conferring to it higher fitness in the instant environment. If the alternative strategy, termed 'random switching' is applied, the cell undergoes transition into the new state not regarding the instant environment. Each strategy comes with the respective cost for its physical realization. Within the framework of evolutionary model, mutations occur as random events which change parameters of the probabilistic models corresponding to the respective switching strategies. Most of the general trends of population averages can be easily understood at the intuitive level, with a few exceptions related to the cases when too low mutation noise hampers population to follow rapid environmental changes. On the other hand, the more detailed study of the parameter distributions reveals much more complex structure than expected. The simulation results may help to understand, at the conceptual level, relation between the population heterogeneity and its environment that could find important implications in various areas, such as cancer therapy or development of risk diversifying strategies.

  7. Sensor trustworthiness in uncertain time varying stochastic environments

    Science.gov (United States)

    Verma, Ajay; Fernandes, Ronald; Vadakkeveedu, Kalyan

    2011-06-01

    Persistent surveillance applications require unattended sensors deployed in remote regions to track and monitor some physical stimulant of interest that can be modeled as output of time varying stochastic process. However, the accuracy or the trustworthiness of the information received through a remote and unattended sensor and sensor network cannot be readily assumed, since sensors may get disabled, corrupted, or even compromised, resulting in unreliable information. The aim of this paper is to develop information theory based metric to determine sensor trustworthiness from the sensor data in an uncertain and time varying stochastic environment. In this paper we show an information theory based determination of sensor data trustworthiness using an adaptive stochastic reference sensor model that tracks the sensor performance for the time varying physical feature, and provides a baseline model that is used to compare and analyze the observed sensor output. We present an approach in which relative entropy is used for reference model adaptation and determination of divergence of the sensor signal from the estimated reference baseline. We show that that KL-divergence is a useful metric that can be successfully used in determination of sensor failures or sensor malice of various types.

  8. Sunlight affects aggregation and deposition of graphene oxide in the aquatic environment.

    Science.gov (United States)

    In this study, we investigate the role of simulated sunlight on the physicochemical properties, aggregation, and deposition of graphene oxide (GO) in aquatic environments. Results show that light exposure under varied environmental conditions significantly impacts the physicochem...

  9. Does the HI Mass Function Vary with Environment?

    Science.gov (United States)

    Minchin, Robert F.

    2017-01-01

    Based on analysis of a large dataset from the ALFALFA survey, Jones et al. (2016) recently claimed that the slope of the HI mass function is constant across different galactic environments, defined by their density. They point out that this finding is “perplexing” given that many previous studies have found that the HI mass functions of groups of galaxies have flat slopes, while the general field has a relatively steep slope. I argue that the analysis of Jones et al., and similar analyses in the past, is flawed as they examine the HI mass function of the galaxies found in environments with a given density, summed across the survey, not the HI mass function actually present in the individual structures at that density. If the position of the knee in the HI mass function were to vary between these structures, then the slope of the HI mass function found by summing across all of the structures with a given density would be steeper than the slope actually found in the individual structures. For example, if a survey were to contain three groups of galaxies, all with flat HI mass functions, but with the ‘knee’, at the mass of the largest galaxy in the group, at 108, 109 and 1010 solar masses, then the summed HI mass function would appear to have a knee at 1010 solar masses and a steep slope below this, rather than the flat slope that is actually present in the individual environments. It is not possible, therefore, to say from the analysis of Jones et al. that there is no dependence of the HI mass function on environment. This scenario explains the “seemingly contradictory findings” of Jones et al. and the earlier studies of individual groups as being due to differences in what is being studies, without having to invoke methodological errors in the derivation of the HI mass function.The Arecibo Observatory is operated by SRI International under a cooperative agreement with the National Science Foundation (AST-1100968), and in alliance with Ana G. M

  10. Titanium (IV) sol-gel chemistry in varied gravity environments

    Science.gov (United States)

    Hales, Matthew; Martens, Wayde; Steinberg, Theodore

    Sol-gel synthesis in reduced gravity is a relatively new topic in the literature and further inves-tigation is essential to realise its potential and application to other sol-gel systems. The sol-gel technique has been successfully applied to the synthesis of silica systems of varying porosity for many diverse applications [1-5]. It is proposed that current methods for the synthesis of silica sol-gels in reduced gravity may be applied to titanium sol-gel processing in order to enhance desirable physical and chemical characteristics of the final materials. The physical and chemical formation mechanisms for titanium alkoxide based sol-gels, to date, is not fully understood. However, various authors [6-9] have described potential methods to control the hydrolysis and condensation reactions of titanium alkoxides through the use of chemical inhibitors. A preliminary study of the reaction kinetics of titanium alkoxide sol-gel reaction in normal gravity was undertaken in order to determine reactant mixtures suitable for further testing under varied gravity conditions of limited duration. Through the use of 1H Nuclear Magnetic Resonance spectroscopy (NMR) for structural analysis of precursor materials, Ultra-Violet-Visible spectroscopy (UV-VIS) and viscosity measurements, it was demonstrated that not only could the rate of the chemical reaction could be controlled, but directed linear chain growth within the resulting gel structure was achievable through the use of increased inhibitor concentrations. Two unique test systems have been fabricated to study the effects of varied gravity (reduced, normal, high) on the formation of titanium sol-gels. Whilst the first system is to be used in conjunction with the recently commissioned drop tower facility at Queensland University of Technology in Brisbane, Australia to produce reduced gravity conditions. The second system is a centrifuge capable of providing high gravity environments of up to 70 G's for extended periods of time

  11. Petrography, palynology and depositional environment of Gelibolu coals, NW Turkey

    Science.gov (United States)

    Demirtaş, Ferdi; Bozcu, Mustafa; Koşun, Erdal

    2014-05-01

    Upper Oligocene and Miocene coal samples collected from two outcrops in the Gelibolu Peninsula, NW Turkey were analyzed petrographically and palynologically to determine the depositional environment of the coals. Microscopic studies reveal that the studied coal samples from both locations are characterized by high amount of huminite group macerals, ranging from 46 to 78% (mineral-included basis). The prevailing maceral from this group is gelinite (31-65%), it can be easily seen on all studied samples, indicative of high gelification degree of organic matter. Relatively low amount of liptinite (does not exceed 9%) and inertinite (does not exceed 8%) are also observed in the coals. The mineral matter content is variable but generally high, varying from 5 to 37%, as in other Turkish coals and consists mostly of clay minerals, quartz, calcite and pyrite. The mean reflectance values range from 0.502 to 0.564% suggesting that rank of coal is subbituminous (ASTM). The chemical properties of coal including calorific value, volatile matter and fixed carbon content are also in accordance with rank of coal. Facies indices based on maceral ratios (Tissue Preservation Index vs. Gelification Index and ABC ternary diagrams) were used to interpret to depositional environment of coals. Low tissue preservation index (TPI) and high gelification index (GI) values are observed. These indices indicate that the coals deposited in limnic environment. High pH and strongly reducing conditions inferred from the presence of framboidal pyrite and also evidenced by low TPI values. The palynological assembly of the coals dominated by angiosperm pollen and spore, however, gymnosperms were rarely seen. Herbaceous/sedge plants are common in Miocene coal samples.

  12. Deposition of diamond like carbon films by using a single ion gun with varying beam source

    Institute of Scientific and Technical Information of China (English)

    JIANG Jin-qiu; Chen Zhu-ping

    2001-01-01

    Diamond like carbon films have been successfully deposited on the steel substrate, by using a single ion gun with varying beam source. The films may appear blue, yellow and transparent in color, which was found related to contaminants from the sample holder and could be avoided. The thickness of the films ranges from tens up to 200 nanometers, and the hardness is in the range 20 to 30 GPa. Raman analytical results reveal the films are in amorphous structure. The effects of different beam source on the films structure are further discussed.

  13. Formation of iron deposits during combustion of coals with varying iron-containing minerals

    Energy Technology Data Exchange (ETDEWEB)

    Alekhnovich, A.N.; Gladkov, V.E. (Vsesoyuznyii Teplotekhnicheskii Institut (USSR). Ural' skii Filial)

    1989-08-01

    Describes an investigation into microstructure and chemical composition of particles in the heavy fraction of ash and iron deposits produced during combustion of coals containing pyrite and siderite. Results show that the structural state of iron deposits varies considerably with different types of coal and in different temperature zones in the boiler duct, and that their formation is the result of adherence of particles with different aggregate states and chemical composition. Interaction between iron deposits and silica results in the formation of firelight (FeSiO{sub 4}) with a melting point of 1200 C. Depending on the ratio, the interaction of a sulfide melt with a firelight melt results in the formation of immiscible liquids, the release of SiO{sub 2} and the formation of silicate and metallic liquid surfaces with unique properties of wettability, and the formation of eutectic compositions (no more than 65% FeS, 35% FeO, 3% SiO{sub 2}) which set at 910-1000 C depending on the FeO and FeS content. Addition of silica increased sticking properties of products of pyrite conversion. In the absence of pyrite, the formation of immiscible liquids with different melting points may result from the reduction of the products of the dissociation of siderite to metallic iron and the formation of a metallic melt with carbon with a melting point of at least 1140 C. 10 refs.

  14. Vacuum deposition of stoichiometric crystalline PbS films: The effect of sulfurizing environment during deposition

    Science.gov (United States)

    Singh, B. P.; Kumar, R.; Kumar, A.; Tyagi, R. C.

    2015-10-01

    Thin film of lead sulfide (PbS) was deposited onto highly cleaned glass and quartz substrates using a vacuum thermal evaporation technique. The effect of the sulfurizing environment on the growth and properties of vacuum-deposited PbS thin film was studied. The ambient sulfurizing environment was created by thermal decomposition of thiourea inside the vacuum chamber during deposition to maintain the stoichiometry and quality of the PbS film. The sulfurizing gas H2S, produced in the thermal decomposition of the solid sulfur containing thiourea readily combines with the cations (Pb2+) without leaving any anions (S2-) at the substrates and also has not produced any excess of sulfur at the substrates. The deposited film was characterized by optical spectroscopy, x-ray diffraction patterns, scanning electron micrographs with energy dispersive analysis of x-rays, and atomic force micrographs. The physical characterization of the deposited PbS film revealed that the surface of film grown in the sulfurizing environment improved and contained more stoichiometric sulfur in comparison to film deposited without the sulfurizing environment.

  15. Error Analysis for RADAR Neighbor Matching Localization in Linear Logarithmic Strength Varying Wi-Fi Environment

    National Research Council Canada - National Science Library

    Zhou, Mu; Tian, Zengshan; Xu, Kunjie; Yu, Xiang; Wu, Haibo

    2014-01-01

    ...) in logarithmic received signal strength (RSS) varying Wi-Fi environment. To the best of our knowledge, little comprehensive analysis work has appeared on the error performance of neighbor matching localization with respect to the deployment of RPs...

  16. On the scaling limits of Galton Watson processes in varying environment

    CERN Document Server

    Bansaye, Vincent

    2011-01-01

    Renormalized sequences of Galton Watson processes converge to Continuous State Branching Processes (CSBP), characterized by a L\\'evy triplet of two numbers and a measure. This paper investigates the case of Galton Watson processes in varying environment and provides an explicit sufficient condition for finite-dimensional convergence in terms of convergence of a characteristic triplet of measures. We recover then classical results on the convergence of Galton Watson processes and we can add exceptional environments provoking positive or negative jumps at fixed times. We also apply this result to derive new results on the Feller diffusion in varying environment and branching processes in random environment. Our approach relies on the backward differential equation satisfied by the Laplace exponent and provides results about explosion, absorption and extinction. Thus, this paper exhibits a general class of CSBP in varying environment which is characterized by a triplet of measures. This provides a first step tow...

  17. Reward-sensitive women overeat in a varied food environment, but only when hungry.

    Science.gov (United States)

    Guerrieri, Ramona; Stanczyk, Nicola; Nederkoorn, Chantal; Jansen, Anita

    2012-12-01

    In the current study we tried to elucidate the relationship between a personality trait, reward sensitivity, and an environmental variable; food variety. Based on scarce previous research we predicted that reward sensitivity would interact with variety in the food environment so that especially high reward sensitive individuals would be vulnerable to overeating in a varied food environment. It turned out that especially the high reward individuals did indeed overeat in a varied food environment. However, this was only the case for the highly reward sensitive individuals who experienced feelings of hunger. In other words, reward sensitivity does not affect food intake in varied food environments as long as feelings of hunger are not present. Future research should concentrate on identifying other factors that interact with the person and the environment to discourage reward-related overeating.

  18. Computational Intelligence for Deepwater Reservoir Depositional Environments Interpretation

    CERN Document Server

    Yu, Tina; Clark, Julian; Sullivan, Morgan; 10.1016/j.jngse.2011.07.014

    2013-01-01

    Predicting oil recovery efficiency of a deepwater reservoir is a challenging task. One approach to characterize a deepwater reservoir and to predict its producibility is by analyzing its depositional information. This research proposes a deposition-based stratigraphic interpretation framework for deepwater reservoir characterization. In this framework, one critical task is the identification and labeling of the stratigraphic components in the reservoir, according to their depositional environments. This interpretation process is labor intensive and can produce different results depending on the stratigrapher who performs the analysis. To relieve stratigrapher's workload and to produce more consistent results, we have developed a novel methodology to automate this process using various computational intelligence techniques. Using a well log data set, we demonstrate that the developed methodology and the designed workflow can produce finite state transducer models that interpret deepwater reservoir depositional...

  19. Depositional environments of the subsurface Cretaceous deposits of southeastern North Carolina

    Science.gov (United States)

    Custer, E. S., Jr.

    1981-02-01

    The subsurface Cretaceous deposits of southeastern North Carolina were analyzed. Six lithologic units were recognized. These are, in ascending stratigraphic order: an unnamed Lower Cretaceous unit, Cape Fear Formation, unnamed Upper Cretaceous unit, Middendorf Formation, Black Creek Formation, and Peedee Formation. The unnamed Lower Cretaceous unit contains interbedded fine to medium grained sands, calcareous sandstones, sandy limestones and clays which were deposited in environments ranging from nearshore to fluvial. The Cape Fear Formation consists of very fine to coarse tan sands interbedded with brown and reddish clays. The Upper Cretaceous unnamed unit is composed of tan and yellow medium to coarse sands interbedded with tan and red clays deposited in braided fluvial environments. The Black Creek Formation consists of lignitic dark clays and coarse to very fine sands. Formation is composed of dark green to greenish-gray, micaceous, glauconitic clays and sands interbedded with calcareous sandstones or sandy limestones.

  20. Doomed pioneers: Event deposition and bioturbation in anaerobic marine environments

    Energy Technology Data Exchange (ETDEWEB)

    Grimm, K.A. (Univ. of California, Santa Cruz (USA)); Follmi, K.B. (Geologisches Institut, Zurich (Switzerland))

    1990-05-01

    Isolated horizons of Thalassinoides and Gyrolithes burrows, in exclusive association with gravity flow deposits within otherwise unbioturbated sediments, indicate that event deposition in oxygen-depleted sedimentary environments may be accompanied by the appearance of allochthonous infauna. In the Miocene Monterey Formation of Alta California and in the Oligocene-Miocene San Gregorio Formation of Baja California Sur, the authors observe compelling evidence that some turbulent sedimentation events entrain living decapod crustaceans. Upon deposition in anaerobic environments, these imported burrowers rework substantial quantities of laminated, commonly organic-rich sediment, in an environment from which they were previously excluded. The persistence of oxygen-depleted environmental conditions limits the survival time of these transported infaunal dwellers and renders them doomed pioneers. The occurrence of Thalassinoides and Gyrolithes, ichnogenera that are generally observed in normal-marine, neritic environments, in anoxic hemipelagic host sediments have been problematic for paleoenvironmental interpretation; in some cases, these features have been incorrectly interpreted to indicate bottom water ventilation and reoxygenation on a basin-wide scale. Accurate recognition of doomed pioneer trace fossil assemblages will permit more precise understanding of paleo-oxygen levels and basin history.

  1. Grain size analysis and depositional environment of shallow marine to basin floor, Kelantan River Delta

    Science.gov (United States)

    Afifah, M. R. Nurul; Aziz, A. Che; Roslan, M. Kamal

    2015-09-01

    Sediment samples were collected from the shallow marine from Kuala Besar, Kelantan outwards to the basin floor of South China Sea which consisted of quaternary bottom sediments. Sixty five samples were analysed for their grain size distribution and statistical relationships. Basic statistical analysis like mean, standard deviation, skewness and kurtosis were calculated and used to differentiate the depositional environment of the sediments and to derive the uniformity of depositional environment either from the beach or river environment. The sediments of all areas were varied in their sorting ranging from very well sorted to poorly sorted, strongly negative skewed to strongly positive skewed, and extremely leptokurtic to very platykurtic in nature. Bivariate plots between the grain-size parameters were then interpreted and the Coarsest-Median (CM) pattern showed the trend suggesting relationships between sediments influenced by three ongoing hydrodynamic factors namely turbidity current, littoral drift and waves dynamic, which functioned to control the sediments distribution pattern in various ways.

  2. Deposit Insurance and Risk Shifting in a Strong Regulatory Environment

    DEFF Research Database (Denmark)

    Bartholdy, Jan; Justesen, Lene Gilje

    This study provides empirical evidence on the moral hazard implications of introducing deposit insurance into a strong regulatory environment. Denmark offers a unique setting because commercial banks and savings banks have different ownership structures, but are subject to the same set of regulat......This study provides empirical evidence on the moral hazard implications of introducing deposit insurance into a strong regulatory environment. Denmark offers a unique setting because commercial banks and savings banks have different ownership structures, but are subject to the same set...... of regulations. The ownership structure in savings banks implies that they have no incentive to increase risk after the implementation of a deposit insurance scheme whereas commercial banks have. Also, at the time of introduction, Denmark had high capital requirements and a strict closure policy. Using...... a difference-in-difference framework we show that commercial banks did not increase their risk compared to savings banks when deposit insurance was introduced. The results also hold for large commercial banks, indicating that the systemic risk did not increase either. Thus for a system with high capital...

  3. Depositional Environment of the Sangkarewang Oil Shale, Ombilin Basin, Indonesia

    Directory of Open Access Journals (Sweden)

    Komang Anggayana

    2014-12-01

    Full Text Available Five samples from 56 m long drill core of lacustrine Sangkarewang oil shale have been studied by means of petrography and organic geochemistry to investigate the organic matter composition and depositional environments of the shale. The organic matter consists of abundant lamalginite (30%, v/v and very limited amount of vitrinite, suggesting aquatic depositional environments with minor terrestrial influence. Organic geochemical analysis exhibits the dominance of pristane, phytane, and generally n-alkanes compounds. These compounds might originate mostly from aquatic photosynthetic organisms. The oil shale was likely deposited in anoxic lake environments, suggested by the presence of framboidal pyrite (6%, v/v and preserved organic matter with total organic carbon (TOC about 4.9%. The pristane/phytane ratio is relatively high about 3.9 and thought as source sensitive rather than redox sensitive. Hopanoid and aryl isoprenoid compounds are present in minor amounts. The latter compounds are interpreted to be derived from green sulfur bacteria dwelling in anoxic and the presence of H2S in bottom water.

  4. Quantitative trait loci × environment interactions for plant morphology vary over ontogeny in Brassica rapa.

    Science.gov (United States)

    Dechaine, Jennifer M; Brock, Marcus T; Iniguez-Luy, Federico L; Weinig, Cynthia

    2014-01-01

    Growth in plants occurs via the addition of repeating modules, suggesting that the genetic architecture of similar subunits may vary between earlier- and later-developing modules. These complex environment × ontogeny interactions are not well elucidated, as studies examining quantitative trait loci (QTLs) expression over ontogeny have not included multiple environments. Here, we characterized the genetic architecture of vegetative traits and onset of reproduction over ontogeny in recombinant inbred lines of Brassica rapa in the field and glasshouse. The magnitude of genetic variation in plasticity of seedling internodes was greater than in those produced later in ontogeny. We correspondingly detected that QTLs for seedling internode length were environment-specific, whereas later in ontogeny the majority of QTLs affected internode lengths in all treatments. The relationship between internode traits and onset of reproduction varied with environment and ontogenetic stage. This relationship was observed only in the glasshouse environment and was largely attributable to one environment-specific QTL. Our results provide the first evidence of a QTL × environment × ontogeny interaction, and provide QTL resolution for differences between early- and later-stage plasticity for stem elongation. These results also suggest potential constraints on morphological evolution in early vs later modules as a result of associations with reproductive timing.

  5. Microstructure Related Characterization of a-Si:H Thin Films PECVD Deposited under Varied Hydrogen Dilution

    Directory of Open Access Journals (Sweden)

    Veronika Vavrunkova

    2007-01-01

    Full Text Available We report on the structure and optical properties of hydrogenated silicon thin films deposited by plasma - enhanced chemical vapor deposition (PECVD from silane diluted with hydrogen in a wide dilution range. The samples deposited with dilutions below 30 were detected as amorphous hydrogenated silicon (a-Si:H with crystalline grains of several nanometers in size which represent the medium-range order of a-Si:H. The optical characterization confirmed increasing ordering with the increasing dilution. The optical band gap was observed to be increasing function of the dilution.

  6. Investigation of effects of varying model inputs on mercury deposition estimates in the Southwest US

    Directory of Open Access Journals (Sweden)

    T. Myers

    2012-04-01

    Full Text Available The Community Multiscale Air Quality (CMAQ model version 4.7.1 was used to simulate mercury wet and dry deposition for a domain covering the contiguous United States (US. The simulations used MM5-derived meteorological input fields and the US Environmental Protection Agency (EPA Clear Air Mercury Rule (CAMR emissions inventory. Using sensitivity simulations with different boundary conditions and tracer simulations, this investigation focuses on the contributions of boundary concentrations to deposited mercury in the Southwest (SW US. Concentrations of oxidized mercury species along the boundaries of the domain, in particular the upper layers of the domain, can make significant contributions to the simulated wet and dry deposition of mercury in the SW US. In order to better understand the contributions of boundary conditions to deposition, inert tracer simulations were conducted to quantify the relative amount of an atmospheric constituent transported across the boundaries of the domain at various altitudes and to quantify the amount that reaches and potentially deposits to the land surface in the SW US. Simulations using alternate sets of boundary concentrations, including estimates from global models (Goddard Earth Observing System-Chem (GEOS-Chem and the Global/Regional Atmospheric Heavy Metals (GRAHM model, and alternate meteorological input fields (for different years are analyzed in this paper. CMAQ dry deposition in the SW US is sensitive to differences in the atmospheric dynamics and atmospheric mercury chemistry parameterizations between the global models used for boundary conditions.

  7. Investigation of effects of varying model inputs on mercury deposition estimates in the Southwest US

    Directory of Open Access Journals (Sweden)

    T. Myers

    2013-01-01

    Full Text Available The Community Multiscale Air Quality (CMAQ model version 4.7.1 was used to simulate mercury wet and dry deposition for a domain covering the continental United States (US. The simulations used MM5-derived meteorological input fields and the US Environmental Protection Agency (EPA Clear Air Mercury Rule (CAMR emissions inventory. Using sensitivity simulations with different boundary conditions and tracer simulations, this investigation focuses on the contributions of boundary concentrations to deposited mercury in the Southwest (SW US. Concentrations of oxidized mercury species along the boundaries of the domain, in particular the upper layers of the domain, can make significant contributions to the simulated wet and dry deposition of mercury in the SW US. In order to better understand the contributions of boundary conditions to deposition, inert tracer simulations were conducted to quantify the relative amount of an atmospheric constituent transported across the boundaries of the domain at various altitudes and to quantify the amount that reaches and potentially deposits to the land surface in the SW US. Simulations using alternate sets of boundary concentrations, including estimates from global models (Goddard Earth Observing System-Chem (GEOS-Chem and the Global/Regional Atmospheric Heavy Metals (GRAHM model, and alternate meteorological input fields (for different years are analyzed in this paper. CMAQ dry deposition in the SW US is sensitive to differences in the atmospheric dynamics and atmospheric mercury chemistry parameterizations between the global models used for boundary conditions.

  8. Diagenesis, provenance and depositional environments of the Bunter Sandstone Formation

    DEFF Research Database (Denmark)

    Olivarius, Mette; Weibel, Rikke; Friis, Henrik

    The Bunter Sandstone Formation in the northern North German Basin has large geothermal potential with high porosity and permeability (generally >15% and >100 mD, respectively) and with pore fluid temperatures that are adequate for geothermal energy production (c. 55–60˚C). A combined investigation...... of diagenesis, provenance and depositional environments is used to identify the reservoir rocks that possess the best quality. This is accomplished by integrating various methods including: seismic reflection data, sedimentological description of cores, mineral quantification by point counting, measurement...

  9. Transformation of cadmium hydroxide to cadmium oxide thin films synthesized by SILAR deposition process: Role of varying deposition cycles

    OpenAIRE

    2016-01-01

    Successive Ionic Layer Adsorption and Reaction (SILAR) was used to deposit nanocrystalline cadmium oxide (CdO) thin films on microscopic glass substrates for various cycles (40–120). This is based on alternate dipping of the substrate in CdCl2 solution made alkaline (pH ∼12) with NaOH, rinsing with distilled water, followed by air treatment with air dryer and annealing at 300 °C for 1 h in air. The prepared films were characterized by X-ray diffraction (XRD), UV–Visible Spectrophotomer (UV–Vi...

  10. Dynamics of a physiologically structured population in a time-varying environment

    DEFF Research Database (Denmark)

    Heilmann, Irene Louise Torpe; Starke, Jens; Andersen, Ken Haste

    2016-01-01

    or less regularly. In order to understand the interaction between an external environmental forcing and the internal dynamics in a population, we examine the response of a physiologically structured population model to a periodic variation in the food resource. We explore the addition of forcing in two......Physiologically structured population models have become a valuable tool to model the dynamics of populations. In a stationary environment such models can exhibit equilibrium solutions as well as periodic solutions. However, for many organisms the environment is not stationary, but varies more...... cases: (A) where the population dynamics is in equilibrium in a stationary environment, and (B) where the population dynamics exhibits a periodic solution in a stationary environment. When forcing is applied in case A, the solutions are mainly periodic. In case B the forcing signal interacts...

  11. Transformation of cadmium hydroxide to cadmium oxide thin films synthesized by SILAR deposition process: Role of varying deposition cycles

    Directory of Open Access Journals (Sweden)

    A.C. Nwanya

    2016-06-01

    Full Text Available Successive Ionic Layer Adsorption and Reaction (SILAR was used to deposit nanocrystalline cadmium oxide (CdO thin films on microscopic glass substrates for various cycles (40–120. This is based on alternate dipping of the substrate in CdCl2 solution made alkaline (pH ∼12 with NaOH, rinsing with distilled water, followed by air treatment with air dryer and annealing at 300 °C for 1 h in air. The prepared films were characterized by X-ray diffraction (XRD, UV–Visible Spectrophotomer (UV–Vis and Scanning Electron Microscopy (SEM. The 80th cycle was observed to be the saturation stage for this reaction. The XRD results confirmed the films to be CdO with some Cd(OH2 phase at higher deposition cycles. The films were polycrystalline in nature having high orientation along (111 and (200 planes. As the number of cycles increases the calculated average crystallite sizes increase gradually up till the 80th cycle after which a gradual decrease in the crystallite size was observed with increasing number of cycles. The films’ transmittance in the visible and near infrared region decreased as the number of cycles increased and ranged between 25 and 80%. This work shows the feasibility of using simple SILAR method at room temperature to obtain Cd(OH2 films which are transformed to CdO thin films after annealing.

  12. Navigation performance in virtual environments varies with fractal dimension of landscape.

    Science.gov (United States)

    Juliani, Arthur W; Bies, Alexander J; Boydston, Cooper R; Taylor, Richard P; Sereno, Margaret E

    2016-09-01

    Fractal geometry has been used to describe natural and built environments, but has yet to be studied in navigational research. In order to establish a relationship between the fractal dimension (D) of a natural environment and humans' ability to navigate such spaces, we conducted two experiments using virtual environments that simulate the fractal properties of nature. In Experiment 1, participants completed a goal-driven search task either with or without a map in landscapes that varied in D. In Experiment 2, participants completed a map-reading and location-judgment task in separate sets of fractal landscapes. In both experiments, task performance was highest at the low-to-mid range of D, which was previously reported as most preferred and discriminable in studies of fractal aesthetics and discrimination, respectively, supporting a theory of visual fluency. The applicability of these findings to architecture, urban planning, and the general design of constructed spaces is discussed.

  13. Structural studies of ZnO nanostructures by varying the deposition parameters

    Science.gov (United States)

    Yunus, S. H. A.; Sahdan, M. Z.; Ichimura, M.; Supee, A.; Rahim, S.

    2017-01-01

    The effect of Zinc Oxide (ZnO) thin film on the growth of ZnO nanorods (NRs) was investigated. The structures of ZnO NRs were synthesized by chemical bath deposition (CBD) method in aqueous solution of N2O6Zn.6H2O and C6H12N4 at 90°C of deposition temperature. One of the ZnO NRs samples was deposited on a ZnO seed layer coated on a glass substrate to investigate the properties of ZnO NRs without receiving effect of other materials. Next, for diode application, the ZnO NRs was deposited on tin monosulfide (SnS) coated on indium-tin-oxide (ITO) coated glass substrate (SnS/ITO). The next, the ZnO structural properties were studied from surface morphology, X-ray diffractometer (XRD) spectra, and chemical composition by using field emission scanning electron microscope (FESEM), XRD and energy dispersive X-ray Spectroscopy (EDX). The growth of ZnO NRs on ZnO seed layer was investigated by ZnO seed layer condition while the growth of ZnO NRs on SnS/ITO was investigated by deposition time and deposition temperature parameters. From FESEM images, aligned ZnO NRs were obtained, and the diameters of ZnO NRs were 0.024-3.94 µm. The SnS thin film was affected by the diameter of ZnO NRs which are the ZnO NRs grow on SnS thin films has a larger diameter compared to ZnO NRs grow on ZnO seed layer. Besides that, all of ZnO peaks observed from XRD corresponding to the wurzite structure and preferentially oriented along the c-axis. In addition, EDX shows a high composition of zinc (Zn) and oxygen (O) signals, which indicated that the NRs are indeed made up of Zn and O.

  14. Deposition of callose in young ovules of two Taraxacum species varying in the mode of reproduction.

    Science.gov (United States)

    Musiał, Krystyna; Kościńska-Pająk, Maria; Antolec, Renata; Joachimiak, Andrzej J

    2015-01-01

    Although callose occurs during megasporogenesis in most flowering plants, the knowledge about its general function and the mechanisms by which the callose layer is formed in particular places is still not sufficient. The results of previous studies suggest a total lack of callose in the ovules of diplosporous plants in which meiosis is omitted or disturbed. This report is the first documentation of callose events in dandelions ovules. We demonstrated the pattern of callose deposition during the formation of megaspores through diplospory of Taraxacum type and during normal meiotic megasporogenesis in apomictic triploid Taraxacum atricapillum and amphimictic diploid Taraxacum linearisquameum. We found the presence of callose in the megasporocyte wall of both diplosporous and sexual dandelions. However, in a diplosporous dandelion, callose predominated at the micropylar pole of megaspore mother cell (MMC) which may be correlated with abnormal asynaptic meiosis and may indicate diplospory of the Taraxacum type. After meiotic division, callose is mainly deposited in the walls between megaspores in tetrads and in diplodyads. In subsequent stages, callose gradually disappears around the chalazal functional megaspore. However, some variations in the pattern of callose deposition within tetrad may reflect variable positioning of the functional megaspore (FM) observed in the ovules of T. linearisquameum.

  15. Varying stress of SiOsub>xsub>Csub>ysub> thin films deposited by plasma polymerization.

    Science.gov (United States)

    Liao, Wei-Bo; Chang, Ya-Chen; Jaing, Cheng-Chung; Cheng, Ching-Long; Lee, Cheng-Chung; Wei, Hung-Sen; Kuo, Chien-Cheng

    2017-02-01

    SiOsub>xsub>Csub>ysub> thin films were deposited by plasma polymerization. The stress of the deposited SiOsub>xsub>Csub>ysub> thin films can be modified by adjusting the beam current, the anode voltage, and the flow rate of hexamethyldisiloxane (HMDSO) gas and oxygen. Reducing the beam current or increasing the flow rate of HMDSO gas increased the linear/cage structure ratio and turned the stress of the SiOsub>xsub>Csub>ysub> thin films from compressive to tensile. The linear/cage structure ratio can be adjusted by changing the composite parameter, W[FM]sub>csub>/[FM]sub>msub>, to control the stress of the deposited plasma polymer films. Multilayers of TiOsub>2sub>/SiOsub>2sub>/TiOsub>2sub> were coated on a SiOsub>xsub>Csub>ysub> plasma polymer film herein, reducing their stress by 70% from 0.06 to 0.018 GPa. The refractive index is 1.55, and the absorption coefficient is less than 10-4 at 550 nm of the SiOsub>xsub>Csub>ysub> films. Superior optical performances of SiOsub>xsub>Csub>ysub> thin films make their use in optical thin films.

  16. Chemical Vapor Deposition at High Pressure in a Microgravity Environment

    Science.gov (United States)

    McCall, Sonya; Bachmann, Klaus; LeSure, Stacie; Sukidi, Nkadi; Wang, Fuchao

    1999-01-01

    In this paper we present an evaluation of critical requirements of organometallic chemical vapor deposition (OMCVD) at elevated pressure for a channel flow reactor in a microgravity environment. The objective of using high pressure is to maintain single-phase surface composition for materials that have high thermal decomposition pressure at their optimum growth temperature. Access to microgravity is needed to maintain conditions of laminar flow, which is essential for process analysis. Based on ground based observations we present an optimized reactor design for OMCVD at high pressure and reduced gravity. Also, we discuss non-intrusive real-time optical monitoring of flow dynamics coupled to homogeneous gas phase reactions, transport and surface processes. While suborbital flights may suffice for studies of initial stages of heteroepitaxy experiments in space are essential for a complete evaluation of steady-state growth.

  17. Quantitative modeling of Escherichia coli chemotactic motion in environments varying in space and time.

    Directory of Open Access Journals (Sweden)

    Lili Jiang

    2010-04-01

    Full Text Available Escherichia coli chemotactic motion in spatiotemporally varying environments is studied by using a computational model based on a coarse-grained description of the intracellular signaling pathway dynamics. We find that the cell's chemotaxis drift velocity v(d is a constant in an exponential attractant concentration gradient [L] proportional, variantexp(Gx. v(d depends linearly on the exponential gradient G before it saturates when G is larger than a critical value G(C. We find that G(C is determined by the intracellular adaptation rate k(R with a simple scaling law: G(C infinity k(1/2(R. The linear dependence of v(d on G = d(ln[L]/dx directly demonstrates E. coli's ability in sensing the derivative of the logarithmic attractant concentration. The existence of the limiting gradient G(C and its scaling with k(R are explained by the underlying intracellular adaptation dynamics and the flagellar motor response characteristics. For individual cells, we find that the overall average run length in an exponential gradient is longer than that in a homogeneous environment, which is caused by the constant kinase activity shift (decrease. The forward runs (up the gradient are longer than the backward runs, as expected; and depending on the exact gradient, the (shorter backward runs can be comparable to runs in a spatially homogeneous environment, consistent with previous experiments. In (spatial ligand gradients that also vary in time, the chemotaxis motion is damped as the frequency omega of the time-varying spatial gradient becomes faster than a critical value omega(c, which is controlled by the cell's chemotaxis adaptation rate k(R. Finally, our model, with no adjustable parameters, agrees quantitatively with the classical capillary assay experiments where the attractant concentration changes both in space and time. Our model can thus be used to study E. coli chemotaxis behavior in arbitrary spatiotemporally varying environments. Further experiments are

  18. Using Australian Acidic Playa Lakes as Analogs for Phyllosilicate and Sulfate Depositional Environments on Mars

    Science.gov (United States)

    Baldridge, A. M.; Michalski, J.; Kargel, J.; Hook, S.; Marion, G.; Crowley, J.; Bridges, N.; Brown, A.; Ribeiro da Luz, B.; de Souza Filho, C. R.; Thomson, B.

    2008-12-01

    Recent work on the origin of martian sulfates and their relationship to phyllosilicate deposits suggest that these deposits formed in different eras of Mars' history, under distinct environmental conditions. In southwestern Meridiani Planum phyllosilicates exist in close proximity to sulfate deposits. One possible explanation for this relationship is that it is an unconformable stratigraphic sequence, representing a significant change in aqueous geochemical conditions over time. Specifically, it may be interpreted to record a change in environment from neutral pH aqueous alteration in the Noachian to an acidic evaporitic system in the late Noachian to the Hesperian. On Earth, two different geochemical systems need not be evoked to explain such chemical variation. Acidic playa lakes in Western Australia have large pH differences separated by only a few tens of meters and demonstrate how highly variable chemistries can coexist over short distances in natural environments. Playa lakes on Earth tend to be dominated by lateral flow of water and salts leading to lateral chemical variation. Heterogeneity of playa mineralogy in Australia is due to the varied source rocks of brines and the mixing of dilute oxidizing brines and freshwater with the saturated evaporitic brines. This is evidenced by the ferricretes in the near-shore environment and more soluble phases in basin interiors. Playa lakes on Mars would be much larger than their terrestrial counterparts, leading to the prevalence of large-scale surface and crustal advection of water and salt rather than short-distance lateral flow, except at lake boundaries. Little or no influx of freshwater would preclude the formation of playa rim (e.g., crater rim) ferricretes and silcretes. Instead, we expect to see mainly vertical facies changes, and any diachronous lateral facies changes are expected to occur on very large spatial scales. Comparison of high spatial resolution, hyperspectral airborne data for Australian playa

  19. Error analysis for RADAR neighbor matching localization in linear logarithmic strength varying Wi-Fi environment.

    Science.gov (United States)

    Zhou, Mu; Tian, Zengshan; Xu, Kunjie; Yu, Xiang; Wu, Haibo

    2014-01-01

    This paper studies the statistical errors for the fingerprint-based RADAR neighbor matching localization with the linearly calibrated reference points (RPs) in logarithmic received signal strength (RSS) varying Wi-Fi environment. To the best of our knowledge, little comprehensive analysis work has appeared on the error performance of neighbor matching localization with respect to the deployment of RPs. However, in order to achieve the efficient and reliable location-based services (LBSs) as well as the ubiquitous context-awareness in Wi-Fi environment, much attention has to be paid to the highly accurate and cost-efficient localization systems. To this end, the statistical errors by the widely used neighbor matching localization are significantly discussed in this paper to examine the inherent mathematical relations between the localization errors and the locations of RPs by using a basic linear logarithmic strength varying model. Furthermore, based on the mathematical demonstrations and some testing results, the closed-form solutions to the statistical errors by RADAR neighbor matching localization can be an effective tool to explore alternative deployment of fingerprint-based neighbor matching localization systems in the future.

  20. Error Analysis for RADAR Neighbor Matching Localization in Linear Logarithmic Strength Varying Wi-Fi Environment

    Directory of Open Access Journals (Sweden)

    Mu Zhou

    2014-01-01

    Full Text Available This paper studies the statistical errors for the fingerprint-based RADAR neighbor matching localization with the linearly calibrated reference points (RPs in logarithmic received signal strength (RSS varying Wi-Fi environment. To the best of our knowledge, little comprehensive analysis work has appeared on the error performance of neighbor matching localization with respect to the deployment of RPs. However, in order to achieve the efficient and reliable location-based services (LBSs as well as the ubiquitous context-awareness in Wi-Fi environment, much attention has to be paid to the highly accurate and cost-efficient localization systems. To this end, the statistical errors by the widely used neighbor matching localization are significantly discussed in this paper to examine the inherent mathematical relations between the localization errors and the locations of RPs by using a basic linear logarithmic strength varying model. Furthermore, based on the mathematical demonstrations and some testing results, the closed-form solutions to the statistical errors by RADAR neighbor matching localization can be an effective tool to explore alternative deployment of fingerprint-based neighbor matching localization systems in the future.

  1. Particle Deposition in Human Lungs due to Varying Cross-Sectional Ellipticity of Left and Right Main Bronchi

    Science.gov (United States)

    Roth, Steven; Oakes, Jessica; Shadden, Shawn

    2015-11-01

    Particle deposition in the human lungs can occur with every breathe. Airbourne particles can range from toxic constituents (e.g. tobacco smoke and air pollution) to aerosolized particles designed for drug treatment (e.g. insulin to treat diabetes). The effect of various realistic airway geometries on complex flow structures, and thus particle deposition sites, has yet to be extensively investigated using computational fluid dynamics (CFD). In this work, we created an image-based geometric airway model of the human lung and performed CFD simulations by employing multi-domain methods. Following the flow simulations, Lagrangian particle tracking was used to study the effect of cross-sectional shape on deposition sites in the conducting airways. From a single human lung model, the cross-sectional ellipticity (the ratio of major and minor diameters) of the left and right main bronchi was varied systematically from 2:1 to 1:1. The influence of the airway ellipticity on the surrounding flow field and particle deposition was determined.

  2. Evidence for change in depositional environment in the Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, P.S.; Rao, Ch.M.

    cm interval were analyzed for calcium carbonate, organic carbon and reduced sulfur contents. Sedimentological analysis indicates that the core contains hemipelagic Globigerina ooze of Holocene age at the top, underlain by sediments depositEd...

  3. TiAlN coatings deposited by triode magnetron sputtering varying the bias voltage

    Energy Technology Data Exchange (ETDEWEB)

    Devia, D.M. [Laboratorio de Fisica del Plasma, Universidad Nacional de Colombia Sede Manizales, Cra. 27 No. 64-60, Manizales, Caldas (Colombia); Laboratorio de Materiales, Universidad Nacional de Colombia Sede Medellin, Sede Medellin, Antioquia (Colombia); Restrepo-Parra, E., E-mail: erestrepopa@unal.edu.co [Laboratorio de Fisica del Plasma, Universidad Nacional de Colombia Sede Manizales, Cra. 27 No. 64-60, Manizales, Caldas (Colombia); Arango, P.J. [Laboratorio de Fisica del Plasma, Universidad Nacional de Colombia Sede Manizales, Cra. 27 No. 64-60, Manizales, Caldas (Colombia); Tschiptschin, A.P. [Escola Politecnica da Universidade de Sao Paulo, Depto. de Engenharia Metalurgica e de Materiais, Sao Paulo, SP (Brazil); Velez, J.M. [Laboratorio de Materiales, Universidad Nacional de Colombia Sede Medellin, Sede Medellin, Antioquia (Colombia)

    2011-05-01

    TiAlN films were deposited on AISI O1 tool steel using a triode magnetron sputtering system. The bias voltage effect on the composition, thickness, crystallography, microstructure, hardness and adhesion strength was investigated. The coatings thickness and elemental composition analyses were carried out using scanning electron microscopy (SEM) together with energy dispersive X-ray (EDS). The re-sputtering effect due to the high-energy ions bombardment on the film surface influenced the coatings thickness. The films crystallography was investigated using X-ray diffraction characterization. The X-ray diffraction (XRD) data show that TiAlN coatings were crystallized in the cubic NaCl B1 structure, with orientations in the {l_brace}1 1 1{r_brace}, {l_brace}2 0 0{r_brace} {l_brace}2 2 0{r_brace} and {l_brace}3 1 1{r_brace} crystallographic planes. The surface morphology (roughness and grain size) of TiAlN coatings was investigated by atomic force microscopy (AFM). By increasing the substrate bias voltage from -40 to -150 V, hardness decreased from 32 GPa to 19 GPa. Scratch tester was used for measuring the critical loads and for measuring the adhesion.

  4. Recent marine deposits reconstruction of two depositional environments of the French Atlantic coast

    Science.gov (United States)

    Pouzet, Pierre; Maanan, Mohamed; Schmidt, Sabine; Athimon, Emmanuelle; Robin, Marc

    2017-04-01

    This work provides a 300-yr high-resolution record of past storm and/or tsunami events using a multi-proxy analysis (137Cs and 210Pb dating, chemical composition and grain size) of sedimentary deposits from two coastal depositional environments of the French Atlantic coast. We analyse two wetland areas situated just behind a narrow coastal sand strip: 1) the Mer Blanche and 2) the Turballe. Evidence for strong extratropical storms and /or tsunamis events can be identified in this central part of the Bay of Biscay from the XIXth to the XXth century. Nine short sediment cores were collected in August 2016 using gravity type corer of 10 inner diameter and 100 cm length. Each core was longitudinally sliced, each half section photographed and described. High-resolution elemental analyses of split sediment cores were done using an Avaatech XRF core scanner. Then sediment cores were sampled every 0.5 cm. Grain size analysis was done using a Malvern 2600 laser beam grain sizer; organic carbon was measured by Leco induction furnace. 137Cs, 210Pb and 226Ra activities were measured on about 2 g dried sediment using a low background, well-type γ spectrometer (Canberra). The 210Pb in excess, which is used for dating, was calculated as the difference of measured 210Pb and of its supported activities (226Ra). The history information is performed using historical documents including narrative sources, ancient maps, records of cities repairs, surveys conducted after a disaster, newspaper from different departmental and national archives, and meteorological data. Coastal depositional environments were affected hardest by extreme environmental and climatological events during the last century. In the Mer Blanche core, three extreme episodes can be observed: i) at 36 cm, sediment is characterized by coarser sand and higher Sr/Al ratio, this episode coincides with a high tidal wave in spring 1937; ii) at 55 cm, we observe the presence of many gravels, they dates back to the high tidal

  5. Environment of deposition of Clear Fork Formation: Yoakum County, Texas

    Energy Technology Data Exchange (ETDEWEB)

    Moore, B.K.

    1987-05-01

    The Clear Fork Formation is Permian (Leonardian) in age and constitutes a major oil-bearing unit in the Permian basin of west Texas. In Yoakum County, west Texas, the upper Clear Fork carbonates record a subtidal upward-shoaling sequence of deposition. A small bryozoan-algal patch reef is situated within these carbonates near the southern edge of the North Basin platform. The reef is completely dolomitized, but paramorphic replacement has facilitated a study of the paleoecology, lateral variations, and community succession within this buildup. Build-ups of this type are scarcely known in strata of Permian age. The reef was apparently founded on a coquina horizon at the base of the buildup. The reef apparently had a low-relief, dome-shaped morphology. The trapping and binding of sediment by bryozoa appear to have been the main constructional process. A significant role was also played by encrusting forams and the early precipitation of submarine cements, both of which added rigidity to the structure. The reef also contains a low-diversity community of other invertebrates. Algal constituents predominate at the basinward edge of the buildup. The reef was formed entirely subaqueously on a broad, relatively shallow tropical marine carbonate shelf environment. An understanding of the lithofacies distribution and paragenesis within this sequence will provide information on porosity variations and the nature and distribution of permeability barriers. Such information is useful in reservoir modeling studies and for secondary recovery techniques in shelf-edge carbonate reservoirs of this type.

  6. Threshold-Based Bit Error Rate for Stopping Iterative Turbo Decoding in a Varying SNR Environment

    Science.gov (United States)

    Mohamad, Roslina; Harun, Harlisya; Mokhtar, Makhfudzah; Adnan, Wan Azizun Wan; Dimyati, Kaharudin

    2017-01-01

    Online bit error rate (BER) estimation (OBE) has been used as a stopping iterative turbo decoding criterion. However, the stopping criteria only work at high signal-to-noise ratios (SNRs), and fail to have early termination at low SNRs, which contributes to an additional iteration number and an increase in computational complexity. The failure of the stopping criteria is caused by the unsuitable BER threshold, which is obtained by estimating the expected BER performance at high SNRs, and this threshold does not indicate the correct termination according to convergence and non-convergence outputs (CNCO). Hence, in this paper, the threshold computation based on the BER of CNCO is proposed for an OBE stopping criterion (OBEsc). From the results, OBEsc is capable of terminating early in a varying SNR environment. The optimum number of iterations achieved by the OBEsc allows huge savings in decoding iteration number and decreasing the delay of turbo iterative decoding.

  7. Understanding processes affecting mineral deposits in humid environments

    Science.gov (United States)

    Seal, Robert R., II; Ayuso, Robert A.

    2011-01-01

    Recent interdisciplinary studies by the U.S. Geological Survey have resulted in substantial progress toward understanding the influence that climate and hydrology have on the geochemical signatures of mineral deposits and the resulting mine wastes in the eastern United States. Specific areas of focus include the release, transport, and fate of acid, metals, and associated elements from inactive mines in temperate coastal areas and of metals from unmined mineral deposits in tropical to subtropical areas; the influence of climate, geology, and hydrology on remediation options for abandoned mines; and the application of radiogenic isotopes to uniquely apportion source contributions that distinguish natural from mining sources and extent of metal transport. The environmental effects of abandoned mines and unmined mineral deposits result from a complex interaction of a variety of chemical and physical factors. These include the geology of the mineral deposit, the hydrologic setting of the mineral deposit and associated mine wastes, the chemistry of waters interacting with the deposit and associated waste material, the engineering of a mine as it relates to the reactivity of mine wastes, and climate, which affects such factors as temperature and the amounts of precipitation and evapotranspiration; these factors, in turn, influence the environmental behavior of mineral deposits. The role of climate is becoming increasingly important in environmental investigations of mineral deposits because of the growing concerns about climate change.

  8. An Adaptive Particle Filtering Approach to Tracking Modes in a Varying Shallow Ocean Environment

    Energy Technology Data Exchange (ETDEWEB)

    Candy, J V

    2011-03-22

    The shallow ocean environment is ever changing mostly due to temperature variations in its upper layers (< 100m) directly affecting sound propagation throughout. The need to develop processors that are capable of tracking these changes implies a stochastic as well as an 'adaptive' design. The stochastic requirement follows directly from the multitude of variations created by uncertain parameters and noise. Some work has been accomplished in this area, but the stochastic nature was constrained to Gaussian uncertainties. It has been clear for a long time that this constraint was not particularly realistic leading a Bayesian approach that enables the representation of any uncertainty distribution. Sequential Bayesian techniques enable a class of processors capable of performing in an uncertain, nonstationary (varying statistics), non-Gaussian, variable shallow ocean. In this paper adaptive processors providing enhanced signals for acoustic hydrophonemeasurements on a vertical array as well as enhanced modal function estimates are developed. Synthetic data is provided to demonstrate that this approach is viable.

  9. Modern sedimentary environments and dynamic depositional systems in the southern Yellow Sea

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Based on analyses of more than 600 surface sediment samples together with large amounts of previous sedimentologic and hydrologic data, the characteristics of modern sedimentary environments and dynamic depositional systems in the southern Yellow Sea (SYS) are expounded, and the controversial formation mechanism of muddy sediments is also discussed. The southern Yellow Sea shelf can be divided into low-energy sedimentary environment and high-energy sedimentary environment; the low- energy sedimentary environment can be further divided into cyclonic and anticyclonic ones, and the high-energy environment is subdivided into high-energy depositional and eroded environments. In the shelf low-energy environments, there developed muddy depositional system. In the central part of the southern Yellow Sea, there deposited the cold eddy sediments under the actions of a meso-scale cyclonic eddy (cold eddy), and in the southeast of the southern Yellow Sea, an anticyclonic eddy muddy depositional system (warm eddy sediment) was formed. These two types of sediments showed evident differences in grain size, sedimentation rate, sediment thickness and mineralogical characteristics. The high-energy environments were covered with sandy sediments on seabed; they appeared mainly in the west, south and northeast of the southern Yellow Sea. In the high-energy eroded environment, large amounts of sandstone gravels were distributed on seabed. In the high-energy depositional environment, the originally deposited fine materials (including clay and fine silt) were gradually re-suspended and then transported to a low-energy area to deposit again. In this paper, the sedimentation model of cyclonic and anticyclonic types of muddy sediments is established, and a systematic interpretation for the formation cause of muddy depositional systems in the southern Yellow Sea is given.

  10. Do larval supply and recruitment vary among chemosynthetic environments of the deep sea?

    Directory of Open Access Journals (Sweden)

    Anna Metaxas

    Full Text Available BACKGROUND: The biological communities that inhabit chemosynthetic environments exist in an ephemeral and patchily distributed habitat with unique physicochemical properties that lead to high endemicity. Consequently, the maintenance and recovery from perturbation of the populations in these habitats is, arguably, mainly regulated by larval supply and recruitment. METHODOLOGY/PRINCIPAL FINDINGS: WE USE DATA FROM THE PUBLISHED SCIENTIFIC LITERATURE TO: (1 compare the magnitudes of and variability in larval supply and settlement and recruitment at hydrothermal vents, seeps, and whale, wood and kelp falls; (2 explore factors that affect these life history processes, when information is available; and (3 explore taxonomic affinities in the recruit assemblages of the different chemosynthetic habitats, using multivariate statistical techniques. Larval supply at vents can vary across segments by several orders of magnitude for gastropods; for bivalves, supply is similar at vents on different segments, and at cold seeps. The limited information on larval development suggests that dispersal potential may be highest for molluscs from cold seeps, intermediate for siboglinids at vents and lowest for the whale-bone siboglinid Osedax. Settlement is poorly studied and only at vents and seeps, but tends to be highest near an active source of emanating fluid in both habitats. Rate of recruitment at vents is more variable among studies within a segment than among segments. Across different chemosynthetic habitats, recruitment rate of bivalves is much more variable than that of gastropods and polychaetes. Total recruitment rate ranges only between 0.1 and 1 ind dm(-2 d(-1 across all chemosynthetic habitats, falling above rates in the non-reducing deep sea. The recruit assemblages at vents, seeps and kelp falls have lower taxonomic breadth, and include more families and genera that have many species more closely related to each other than those at whale and wood

  11. Do larval supply and recruitment vary among chemosynthetic environments of the deep sea?

    Science.gov (United States)

    Metaxas, Anna; Kelly, Noreen E

    2010-07-19

    The biological communities that inhabit chemosynthetic environments exist in an ephemeral and patchily distributed habitat with unique physicochemical properties that lead to high endemicity. Consequently, the maintenance and recovery from perturbation of the populations in these habitats is, arguably, mainly regulated by larval supply and recruitment. WE USE DATA FROM THE PUBLISHED SCIENTIFIC LITERATURE TO: (1) compare the magnitudes of and variability in larval supply and settlement and recruitment at hydrothermal vents, seeps, and whale, wood and kelp falls; (2) explore factors that affect these life history processes, when information is available; and (3) explore taxonomic affinities in the recruit assemblages of the different chemosynthetic habitats, using multivariate statistical techniques. Larval supply at vents can vary across segments by several orders of magnitude for gastropods; for bivalves, supply is similar at vents on different segments, and at cold seeps. The limited information on larval development suggests that dispersal potential may be highest for molluscs from cold seeps, intermediate for siboglinids at vents and lowest for the whale-bone siboglinid Osedax. Settlement is poorly studied and only at vents and seeps, but tends to be highest near an active source of emanating fluid in both habitats. Rate of recruitment at vents is more variable among studies within a segment than among segments. Across different chemosynthetic habitats, recruitment rate of bivalves is much more variable than that of gastropods and polychaetes. Total recruitment rate ranges only between 0.1 and 1 ind dm(-2) d(-1) across all chemosynthetic habitats, falling above rates in the non-reducing deep sea. The recruit assemblages at vents, seeps and kelp falls have lower taxonomic breadth, and include more families and genera that have many species more closely related to each other than those at whale and wood falls. Vents also have the most uneven taxonomic structure

  12. Berau coal in East Kalimantan; Its petrographics characteristics and depositional environment

    Directory of Open Access Journals (Sweden)

    Nana Suwarna

    2014-06-01

    Full Text Available http://dx.doi.org/10.17014/ijog.vol2no4.20071To asses the characteristics of the Early to Middle Miocene Berau coal in the Berau Basin, leading to interpretation of coal depositional environments, some fresh outcrop and subcrop samples and also drill cores of the coals have been analyzed microscopically. Coal petrographic analysis was performed on twenty four coal samples from the Middle Miocene Lati Formation. Vitrinite, present in a high value, and ranging between 66.2 - 96.2%, is dominated by vitrinite B. On the other hand, inertinite and exinite, showing a similar value, exist in a low to moderate amount. Vitrinite reflectance, present in a low value, varies from 0.40 - 0.58%. Low mineral matter content is dominated by clay minerals (0.4 - 6.6% with minor pyrite. Transitions from wet and very wet forested swamps to drier conditions with lower tree density are indicated by the higher content of vitrinite B, whilst a reverse trend is indicated by the lower content of vitrinite A. Petrographic indices obtained from facies diagnostic macerals show that an accumulation of the ancient peats under prevailing relatively wet limited influx clastic marsh to very wet forest swamps or moors is considered. The composition of the coal samples supports the interpretation of a system of fluvial to meandering streams in an upper delta plain environment. The original peat-forming vegetation was composed mainly of cellulose rich, shrub-like plants, tree ferns, herbaceous plant communities, with minor amount of trees. Thereby, the organic facies concept is thus applicable in basin studies context and has potential to become an additional tool for depositional environment interpretation.  

  13. The Effect of Varying the Composition of Fingerprint Sweat Deposits on the Corrosion of Brass and Fingerprint Visibility.

    Science.gov (United States)

    Cooper-Dunn, Alice; Jones, Owen; Bond, John W

    2017-02-07

    Corrosion of α-phase brass by sebaceous sweat fingerprint deposits produced identifiable impressions in a majority of samples (n = 40) 4 days after deposition. Combining sebaceous with eccrine sweat yielded a greater percentage of identifiable fingerprint deposits, although this increase was not statistically significant. Production of identifiable fingerprints from eccrine sweat deposits was dependent on the sampling time of year with deposits taken during summer months giving similar percentages of identifiable fingerprints to sebaceous deposits. A statistically significant positive correlation was found between elapsed days after deposition and identifiable eccrine (ρ = 0.787, p < 0.05), sebaceous (ρ = 0.724, p < 0.05), and eccrine/sebaceous mixture (ρ = 0.908, p < 0.01) fingerprints deposited during summer months. The summer increase in the percentage of identifiable eccrine sweat deposits was statistically significant compared to winter eccrine deposits (p < 0.0001). Observations were consistent with results obtained from artificial sebaceous and eccrine sweat.

  14. Facies patterns and depositional environments of Palaeozoic cephalopod limestones

    Science.gov (United States)

    Wendt, J.; Aigner, T.

    1985-07-01

    In the eastern Anti-Atlas (Morocco) a platform and basin topography was established during the late Devonian, probably as a result of early Variscan tensional tectonics. Cephalopod limestones were deposited on shallow pelagic platforms, platform slopes and shallow, slowly subsiding basins. On the platform a transition from land areas into nearshore quartzose brachiopod coquinas, crinoidal limestones, condensed cephalopod limestones and finally into nodular limestones is observed. The latter often become disintegrated into incipient debris flows which pass into nodular limestone/marl alternations of a shallow basin. Deeper basins with shale sedimentation lack cephalopod limestones. Similar facies types also occur in the late Devonian of the Montagne Noire (France), Rheinisches Schiefergebirge (West Germany), Moravian Karst (Czechoslovakia), Holy Cross Mountains (Poland) and in the early Carboniferous of the Cantabrian Mountains (Spain). Due to strong late Variscan compressional tectonics and limited outcrops, detailed facies patterns could not be mapped in these regions, but the same facies types as in the eastern Anti-Atlas suggest similar coast/platform, slope and shallow basin topographies. During cephalopod limestone deposition water depth on the platforms was in the order of several tens to about one hundred metres, as is inferred from repeated subaerial exposures and distinctive depositional and faunal/floral features. Water depth in the adjacent shallow basins might have reached several hundreds of metres. Cephalopod limestones represent a typical stage in the evolution of geosynclines, characterized by extremely low sedimentation rates (1-5 m m.y. -1). This stage is preceded by deposition of thick neritic clastics and/or carbonates and is succeeded by deposition of deep-water clastics or flysch.

  15. Effects of Varying Shrub Density on Erosion and Deposition During a Large Flood, Rio Puerco, New Mexico

    Science.gov (United States)

    Griffin, E. R.; Friedman, J. M.; Vincent, K. R.

    2010-12-01

    A large flood in August 2006 following saltcedar control efforts along a 12-km segment of the Rio Puerco provided an opportunity to measure the effects of varying shrub density on down-valley flood flow and sediment transport. Post-flood field observations in two 3-km long arroyo segments, one in the sprayed reach and one downstream from the sprayed reach, indicate the density and distribution of woody vegetation had a substantial effect on locations and magnitudes of sediment erosion and deposition. In the reach sprayed with herbicide three years before the flood, in which dense woody stems covered only about 30% of the pre-flood (2005) floodplain, average channel width increased by 63% during the flood. Downstream from the sprayed reach, where both pre-and post-flood shrubs covered 50% of the floodplain, erosion was limited to sites where flood flow through sharp bends undercut the arroyo wall. Flow and suspended sediment transport were computed for two 500-m-long floodplain segments, one in the sprayed reach and one downstream from the sprayed reach. Large volumes of fine-grain sediment (fine to very fine sand and silt) were available for transport during the flood in both reaches. In the reach sprayed with herbicide, dense canopy (dominantly saltcedar; Tamarix spp.) remained only within 10-m-wide linear bands oriented along the present or former channel and in isolated, small shrubs scattered about the floodplain. Downstream from the sprayed reach, adjacent shrub bands were closely spaced, with canopies touching in many areas. Mature saltcedar along the Rio Puerco have rigid, dense stems more than 2 m high, whereas floodplain flow depths during the August 2006 event were on the order of 1 m. Drag on the stems was computed using the average stem density (average stem diameter divided by average stem spacing squared) determined from a large number of measurements along the Rio Puerco, 0.35 m-1 (Friedman and others, unpublished data, 2004). Computations of flow

  16. The stratigraphy, depositional processes, and environment of the late Pleistocene Polallie-period deposits at Mount Hood Volcano, Oregon, USA

    Science.gov (United States)

    Thouret, Jean-Claude

    2005-08-01

    The Polallie eruptive period of Mt. Hood, Oregon, is the last major episode of eruption and dome growth, before the late Holocene activity which was centered at Crater Rock. A volume of 4-8 km 3 of Polallie deposits forms an apron of ca. 60 km 2 on the east, northeast and southeast flanks. The Polallie deposits can be divided, stratigraphically, into four groups: Group I rockslide avalanche and pyroclastic-flow deposits; Group II debris-flow and pyroclastic-flow deposits that suggest some explosive activity and remobilization of pyroclastic debris in a glacial environment; Group III block-and-ash flow deposits that attest to summit dome growth; Group IV alternating debris-flow deposits, glacial sediments, and reworked pyroclastic-flow deposits that indicate a decrease in dome activity and an increase in erosion and transport. Group III clearly indicates frequent episodes of dome growth and collapse, whereas Groups II and IV imply increasing erosion and, conversely, decreasing volcanic activity. The Polallie period occurred in the late Pleistocene during and just after the last Alpine glaciation, which is named Evans Creek in the Cascade Range. According to four K-Ar age dates on lava flows interbedded with Polallie deposits and to published minimum 14C ages on tephra and soils overlying these deposits, the Polallie period had lasted 15,000-22,000 years between 28-34 ka and 12-13 ka. From stratigraphic subdivisions, sedimentary lithofacies and features and from the grain-size and geochemical data, we infer that the Polallie depositional record is a result of the interplay of several processes acting during a long-lasting period of dome growth and destruction. The growth of several domes near the present summit was intermittent, because each group of sediments encompasses primary (pyroclastic) and secondary (volcaniclastic and epiclastic) deposition. Direct deposition of primary material has occurred within intervals of erosion that have probably included meltwater

  17. Local Measurement of Fuel Energy Deposition and Heat Transfer Environment During Fuel Lifetime Using Controlled Calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Don W. Miller; Andrew Kauffmann; Eric Kreidler; Dongxu Li; Hanying Liu; Daniel Mills; Thomas D. Radcliff; Joseph Talnagi

    2001-12-31

    A comprehensive description of the accomplishments of the DOE grant titled, ''Local Measurement of Fuel Energy Deposition and Heat Transfer Environment During Fuel Lifetime using Controlled Calorimetry''.

  18. Structural, morphological, electrical, and optical properties of silver thin films of varying thickness deposited on cupric oxide

    Science.gov (United States)

    Hajakbari, Fatemeh; Shafieinejad, Farzaneh

    2016-03-01

    In this investigation, silver (Ag) films of varying thickness (25-100 nm) were grown on cupric oxide (CuO) on silicon and quartz. The CuO preparation was carried out by the thermal oxidation annealing of copper (Cu) thin films deposited by DC magnetron sputtering. The physical properties of the prepared films were studied by different techniques. Rutherford backscattering spectroscopy (RBS) analysis indicated that the Ag film thickness was about 25-100 nm. X-ray diffraction (XRD) results showed that by increasing Ag thickness, the film crystallinity was improved. Also, atomic force microscopy (AFM) and scanning electron microscopy (SEM) results demonstrated that the surface morphology and the grain size were affected by the Ag film thickness. Furthermore, the electrical resistivity of films determined by four-point probe measurements versus the Ag film thickness was discussed. A reduction in the optical band gap energy of CuO is observed from 1.51 to 1.42 eV with an increase in Ag film thickness to 40 nm in Ag/CuO films.

  19. Deposit model for heavy-mineral sands in coastal environments: Chapter L in Mineral deposit models for resource assessment

    Science.gov (United States)

    Van Gosen, Bradley S.; Fey, David L.; Shah, Anjana K.; Verplanck, Philip L.; Hoefen, Todd M.

    2014-01-01

    This report provides a descriptive model of heavy-mineral sands, which are sedimentary deposits of dense minerals that accumulate with sand, silt, and clay in coastal environments, locally forming economic concentrations of the heavy minerals. This deposit type is the main source of titanium feedstock for the titanium dioxide (TiO2) pigments industry, through recovery of the minerals ilmenite (Fe2+TiO3), rutile (TiO2), and leucoxene (an alteration product of ilmenite). Heavy-mineral sands are also the principal source of zircon (ZrSiO4) and its zirconium oxide; zircon is often recovered as a coproduct. Other heavy minerals produced as coproducts from some deposits are sillimanite/kyanite, staurolite, monazite, and garnet. Monazite [(Ce,La,Nd,Th)PO4] is a source of rare earth elements as well as thorium, which is used in thorium-based nuclear power under development in India and elsewhere.

  20. Early Archaean sedimentary basins: depositional environment and hydrothermal systems :

    NARCIS (Netherlands)

    Vries, Sjoukje Tsjitske de

    2004-01-01

    The topic of this thesis is the Early Archaean environment and hydrothermal systems in the Barberton Greenstone Belt (BGB) in South Africa, and the Coppin Gap Greenstone Belt (CGGB) in the Pilbara, Australia. Focus within these greenstone belts is on the ~3.45-3.42 Ga Buck Ridge volcano-sedimentary

  1. Nitrogen deposition as an important nutrient from the environment and its impact on ecosystems in China

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    As an example of atmospheric nitrogen(N) deposition,the paper summarizes the definition,form and amount of nutrient from the environment(NFE) and the relationship between NFE and anthro-pogenic reactive N emission.Based on our own study and published articles,we find that N wet and dry deposition has been an important nutrient resource in agricultural and natural ecosystems in China.The total amount of N deposition and other environment-derived N in China was up to 18 Tg N/a,equal to ap-proximately 60% of the national N fertilizer consumption.Nitrogen deposition is expected to contribute substantially to nutrient cycling and net primary productivity in various ecosystems.Therefore,it is crucial to utilize this environment-derived nutrient resource by integrated nutrient resource management in order to realize the sustainable development of both agricultural and non-agricultural ecosystems.

  2. Spreading and generalized propagating speeds of discrete KPP models in time varying environments

    Institute of Scientific and Technical Information of China (English)

    Wenxian SHEN

    2009-01-01

    The current paper deals with spatial spreading and front propagating dynamics for spatially discrete KPP (Kolmogorov, Petrovsky and Paskunov) models in time recurrent environments, which include time periodic and almost periodic environments as special cases. The notions of spreading speed interval, generalized propagating speed interval, and traveling wave solutions are first introduced, which are proper modifications of those introduced for spatially continuous KPP models in time almost periodic environments. Among others, it is then shown that the spreading speed interval in a given direction is the minimal generalized propagating speed interval in that direction. Some important upper and lower bounds for the spreading and generalized propagating speed intervals are provided. When the environment is unique ergodic and the so called linear determinacy condition is satisfied, it is shown that the spreading speed interval in any direction is a singleton (called the spreading speed), which equals the classical spreading speed if the environment is actually periodic. Moreover, in such a case, a variational principle for the spreading speed is established and it is shown that there is a front of speed c in a given direction if and only if c is greater than or equal to the spreading speed in that direction.

  3. Mineral deposits of the Silica plateau – evaluation of selected geological factors of the environment

    Directory of Open Access Journals (Sweden)

    BalហBartolomej

    2001-12-01

    Full Text Available The Silica plateau is a part of a greatest karst area in the Slovak republic - Protected Landscape Area Slovak karst (CHKO Slovenský kras. Karst areas belong to the most sensitive environments, from the point of view of impacts caused by anthropogenous activities. This area reacts sensitively, disturbing the environmental balance caused by mining of mineral deposits. Three mineral deposits of industrial rocks: one deposit of decorative stone - Silická Brezová and two deposits of building stone – Silická Brezová I and Lipovník, respectively, were registered on January 1-st, 2001 in the territory of the Silica plateau. Some deposits utilized in the past namely two deposits of building raw materials (Hrušov and Krásnohorská Dlhá Lúka and one Pb-Zn ore deposit (Ardovo are also mentioned and evaluated in the paper. From the point of view of economical potential of the area, mineral deposits have a character of geopotentials. However the utilization of deposits represents negative anthropogenous impact. When compared with another forms of optimal and rational utilization of the country, e.g. agriculture, forestry, water management, construction, tourism etc., mineral deposits have a character of geobarriers. This research was carried out in the frame of the VEGA Grant No. 1/6090/1999.

  4. Evaluation of the Survivability of Microorganisms Deposited on Filtering Respiratory Protective Devices under Varying Conditions of Humidity

    Directory of Open Access Journals (Sweden)

    Katarzyna Majchrzycka

    2016-01-01

    Full Text Available Bioaerosols are common biological factors in work environments, which require routine use of filtering respiratory protective devices (FRPDs. Currently, no studies link humidity changes in the filter materials of such devices, during use, with microorganism survivability. Our aim was to determine the microclimate inside FRPDs, by simulating breathing, and to evaluate microorganism survivability under varying humidity conditions. Breathing was simulated using commercial filtering facepiece respirators in a model system. Polypropylene melt-blown nonwoven fabrics with moisture contents of 40%, 80%, and 200%, were used for assessment of microorganisms survivability. A modified AATCC 100-2004 method was used to measure the survivability of ATCC and NCAIM microorganisms: Escherichia coli, Staphylococcus aureus, Bacillus subtilis, Candida albicans and Aspergillus niger. During simulation relative humidity under the facepiece increased after 7 min of usage to 84%–92% and temperature increased to 29–30 °C. S. aureus survived the best on filter materials with 40%–200% moisture content. A decrease in survivability was observed for E. coli and C. albicans when mass humidity decreased. We found that B. subtilis and A. niger proliferated for 48–72 h of incubation and then died regardless of the moisture content. In conclusion, our tests showed that the survivability of microorganisms on filter materials depends on the amount of accumulated moisture and microorganism type.

  5. Disparate relatives: Life histories vary more in genera occupying intermediate environments

    NARCIS (Netherlands)

    Hermant, M.; Hennion, F.; Bartish, I.V.; Yguel, B.; Prinzing, A.

    2012-01-01

    Species within clades are commonly assumed to share similar life history traits, but within a given region some clades show much greater variability in traits than others. Are variable clades older, allowing more time for trait diversification? Or do they occupy particular environments, providing a

  6. Youth Walking and Biking Rates Vary by Environments around 5 Louisiana Schools

    Science.gov (United States)

    Gustat, Jeanette; Richards, Katherine; Rice, Janet; Andersen, Lori; Parker-Karst, Kathryn; Cole, Shalanda

    2015-01-01

    Background: The prevalence of obesity in children is high, and many do not meet physical activity recommendations. The Safe Routes to School (SRTS) program encourages school-aged children to walk and bike to school. We assessed the condition of the walking/biking environment around schools in Louisiana prior to the state's first SRTS program.…

  7. Thermal dynamic simulation of wall for building energy efficiency under varied climate environment

    Science.gov (United States)

    Wang, Xuejin; Zhang, Yujin; Hong, Jing

    2017-08-01

    Aiming at different kind of walls in five cities of different zoning for thermal design, using thermal instantaneous response factors method, the author develops software to calculation air conditioning cooling load temperature, thermal response factors, and periodic response factors. On the basis of the data, the author gives the net work analysis about the influence of dynamic thermal of wall on air-conditioning load and thermal environment in building of different zoning for thermal design regional, and put forward the strategy how to design thermal insulation and heat preservation wall base on dynamic thermal characteristic of wall under different zoning for thermal design regional. And then provide the theory basis and the technical references for the further study on the heat preservation with the insulation are in the service of energy saving wall design. All-year thermal dynamic load simulating and energy consumption analysis for new energy-saving building is very important in building environment. This software will provide the referable scientific foundation for all-year new thermal dynamic load simulation, energy consumption analysis, building environment systems control, carrying through farther research on thermal particularity and general particularity evaluation for new energy -saving walls building. Based on which, we will not only expediently design system of building energy, but also analyze building energy consumption and carry through scientific energy management. The study will provide the referable scientific foundation for carrying through farther research on thermal particularity and general particularity evaluation for new energy saving walls building.

  8. Environment protection through detection of hot spots using thermography in coal deposits before self ignition

    OpenAIRE

    2009-01-01

    In this paper is presented a way to contribute to the environmental protection when it comes to coal which waits in big deposits to be burned for energy production. Because of certain parameters, in some places, the deposited coal could overheat and self ignite, thus loosing its caloric properties and even lead to fire. In this case the losses could be even higher, and the effect on the environment even worse. In order to prevent this self ignition to happen, an infrar...

  9. Pseudomonas putida and Pseudomonas fluorescens Species Group Recovery from Human Homes Varies Seasonally and by Environment.

    Directory of Open Access Journals (Sweden)

    Susanna K Remold

    Full Text Available By shedding light on variation in time as well as in space, long-term biogeographic studies can help us define organisms' distribution patterns and understand their underlying drivers. Here we examine distributions of Pseudomonas in and around 15 human homes, focusing on the P. putida and P. fluorescens species groups. We describe recovery from 10,941 samples collected during up to 8 visits per home, occurring on average 2.6 times per year. We collected a mean of 141 samples per visit, from sites in most rooms of the house, from the surrounding yards, and from human and pet occupants. We recovered Pseudomonas in 9.7% of samples, with the majority of isolates being from the P. putida and P. fluorescens species groups (approximately 62% and 23% of Pseudomonas samples recovered respectively. Although representatives of both groups were recovered from every season, every house, and every type of environment sampled, recovery was highly variable across houses and samplings. Whereas recovery of P. putida group was higher in summer and fall than in winter and spring, P. fluorescens group isolates were most often recovered in spring. P. putida group recovery from soils was substantially higher than its recovery from all other environment types, while higher P. fluorescens group recovery from soils than from other sites was much less pronounced. Both species groups were recovered from skin and upper respiratory tract samples from healthy humans and pets, although this occurred infrequently. This study indicates that even species that are able to survive under a broad range of conditions can be rare and variable in their distributions in space and in time. For such groups, determining patterns and causes of stochastic and seasonal variability may be more important for understanding the processes driving their biogeography than the identity of the types of environments in which they can be found.

  10. Low frequency dove coos vary across noise gradients in an urbanized environment.

    Science.gov (United States)

    Guo, Fengyi; Bonebrake, Timothy C; Dingle, Caroline

    2016-08-01

    Urbanization poses a challenge to bird communication due to signal masking by ambient noise and reflective surfaces that lead to signal degradation. Bird species (especially oscines) have been shown to alter their singing behaviour to increase signal efficiency in highly urbanized environments. However, few studies on the effects of noise on song structure have included birds with low frequency vocal signals which may be especially vulnerable to noise pollution due to significant frequency overlap of their signals with traffic noise. We compared the perch coos of spotted doves (Streptopelia chinensis), a species with very low frequency vocalizations, in different background noise levels across urban and peri-urban areas in Hong Kong. We documented a 10% upward shift in the minimum frequency of coos of spotted doves across the noise gradient (a relatively small but significant shift), and a reduced maximum frequency in urban habitats with a higher density of built up area. Hong Kong doves had significantly higher minimum and maximum frequencies than doves from throughout their range (from mostly rural sites). Our results indicate that urban species with extremely low sound frequencies such as doves can alter their vocalizations in response to variable urban acoustic environments.

  11. Glycol cold thermal energy storage systems : performance and the effect of varying environment temperature

    Energy Technology Data Exchange (ETDEWEB)

    Bakan, K.; Dincer, I.; Rosen, M.A. [Univ. of Ontario Inst. of Technology, Oshawa, ON (Canada). Faculty of Engineering and Applied Science

    2006-07-01

    This paper examined the effect of varying ambient temperatures on glycol cold thermal energy storage (CTES) systems. When glycol thermal storage is incorporated into a new or existing building, a low temperature chilled-water supply allows the use of low-temperature air distribution and smaller fans and ducts. A reduction and shift in peak electric power demand can be realized through the use of glycol CTES as it permits the storage of night-time electric power. This study investigated the thermodynamic system parameters of: storage temperature; storage heat load; exergy destructions; and energy and exergy efficiencies. A storage tank with a capacity of 150,000 kg was used in the investigation. The air-conditioning cycle was simulated using the commercial software package Engineering Equation Solver (EES). Exergy analyses considered quantities of exergy, energy and mass. It was concluded that the exergy efficiency of the system was approximately 46 per cent less than energy efficiency due to irreversibilities. Results indicated that maximum energy efficiency was 75 per cent, and the corresponding exergy efficiency was 40 per cent for a 50 degrees C ambient air temperature. 13 refs., 5 figs.

  12. Atrazine and terbutryn degradation in deposits from groundwater environment within the boreal region in Lahti, Finland.

    Science.gov (United States)

    Talja, K Marja; Kaukonen, Sanna; Kilpi-Koski, Johanna; Malin, Ismo; Kairesalo, Timo; Romantschuk, Martin; Tuominen, Jari; Kontro, Merja H

    2008-12-24

    The degradation of pesticides atrazine and terbutryn was investigated under aerobic and anaerobic conditions in the northern boreal region subsurface deposits and sterilized controls from the depths of 6.3-21.0 m below the surface and 1.2-16.9 m below the groundwater table. During 1.3-1.7 years of laboratory incubation, atrazine degradation under aerobic conditions varied from rapid (half-live 38 days) to no degradation. Anaerobically, atrazine half-lives were 430-829 days. Organic matter, nitrogen, and lead in deposits correlated positively with the atrazine concentration in groundwater. Aerobic and anaerobic terbutryn half-lives were 193-644 and 266-400 days, respectively. Microbial aerobic atrazine and terbutryn degradation was confirmed in the deep deposits near the water table. Under aerobic conditions, the high amounts of Cr, Mn, Ni, and Zn in deposits decreased the chemical degradation of terbutryn.

  13. ZigBee’s Received Signal Strength and Latency Evaluation under Varying Environments

    Directory of Open Access Journals (Sweden)

    H. H. R. Sherazi

    2016-01-01

    Full Text Available Being self-configured, self-organized, and self-healing low power technology, ZigBee has obtained significant attention in last few years for achieving ubiquitous communication among various devices within a Personal Area Network (PAN. Even after a decade of its emergence, it has been well serving the communication needs of numerous modern applications belonging to multiple industries and is still a spotlight for the researchers working on certain aspects to enhance productivity along with a major cost reduction. Despite its robust communication nature, it heavily depends upon the context and is prone to the external effects that may cause a serious threat to prospective applications. This paper presents the novel experimental analysis conducted on real test beds to evaluate the impact of continuously changing communication environment on various parameters, for example, RSSI (Received Signal Strength Indicator and latency in the presence of multiple obstacles that may lead to severe degradation in the overall performance. Eventually, we suggest a suitable frame size for ZigBee based on our results deduced from the experimental study.

  14. Bacterial Community Composition Associated with Pyrogenic Organic Matter (Biochar) Varies with Pyrolysis Temperature and Colonization Environment.

    Science.gov (United States)

    Dai, Zhongmin; Barberán, Albert; Li, Yong; Brookes, Philip C; Xu, Jianming

    2017-01-01

    contributes to soil biogeochemical cycling. This study identified the bacterial community composition associated with PyOMs on the basis of high-throughput sequencing and demonstrated that both PyOM pyrolysis temperature and the colonization environment determined the bacterial community composition. Our work increases our understanding of the dominant phylogenetic taxa associated with PyOMs, demonstrates mechanisms mediating microbial metabolism and growth in PyOMs, and expands a new research area for pyrogenic organic matter. This study identified the bacterial community composition associated with PyOM, which is widely distributed in the environment. Most bacterial OTUs preferentially thrived on PyOM pyrolyzed at low temperature, while some specific OTUs thrived on PyOM pyrolyzed at high temperature.

  15. Evaluating the Contributions of Atmospheric Deposition of Carbon and Other Nutrients to Nitrification in Alpine Environments

    Science.gov (United States)

    Oldani, K. M.; Mladenov, N.; Williams, M. W.

    2013-12-01

    The Colorado Front Range of the Rocky Mountains contains undeveloped, barren soils, yet in this environment there is strong evidence for a microbial role in increased nitrogen (N) export. Barren soils in alpine environments are severely carbon-limited, which is the main energy source for microbial activity and sustenance of life. It has been shown that atmospheric deposition can contain high amounts of organic carbon (C). Atmospheric pollutants, dust events, and biological aerosols, such as bacteria, may be important contributors to the atmospheric organic C load. In this stage of the research we evaluated seasonal trends in the chemical composition and optical spectroscopic (fluorescence and UV-vis absorbance) signatures of snow, wet deposition, and dry deposition in an alpine environment at Niwot Ridge in the Rocky Mountains of Colorado to obtain a better understanding of the sources and chemical character of atmospheric deposition. Our results reveal a positive trend between dissolved organic carbon concentrations and calcium, nitrate and sulfate concentrations in wet and dry deposition, which may be derived from such sources as dust and urban air pollution. We also observed the presence of seasonally-variable fluorescent components that may be attributed to fluorescent pigments in bacteria. These results are relevant because atmospheric inputs of carbon and other nutrients may influence nitrification in barren, alpine soils and, ultimately, the export of nitrate to alpine watersheds.

  16. Hierarchical Distributed-Lag Models: Exploring Varying Geographic Scale and Magnitude in Associations Between the Built Environment and Health.

    Science.gov (United States)

    Baek, Jonggyu; Sanchez-Vaznaugh, Emma V; Sánchez, Brisa N

    2016-03-15

    It is well known that associations between features of the built environment and health depend on the geographic scale used to construct environmental attributes. In the built environment literature, it has long been argued that geographic scales may vary across study locations. However, this hypothesized variation has not been systematically examined due to a lack of available statistical methods. We propose a hierarchical distributed-lag model (HDLM) for estimating the underlying overall shape of food environment-health associations as a function of distance from locations of interest. This method enables indirect assessment of relevant geographic scales and captures area-level heterogeneity in the magnitudes of associations, along with relevant distances within areas. The proposed model was used to systematically examine area-level variation in the association between availability of convenience stores around schools and children's weights. For this case study, body mass index (weight kg)/height (m)2) z scores (BMIz) for 7th grade children collected via California's 2001-2009 FitnessGram testing program were linked to a commercial database that contained locations of food outlets statewide. Findings suggested that convenience store availability may influence BMIz only in some places and at varying distances from schools. Future research should examine localized environmental or policy differences that may explain the heterogeneity in convenience store-BMIz associations.

  17. The depositional environment of Jurassic organic-rich sedimentary rocks in NW Europe : a biomarker approach

    NARCIS (Netherlands)

    Kaam-Peters, H.M.E.

    1997-01-01

    Information on the depositional environment of sediments and sedimentary rocks can be obtained in several ways, using e.g. sedimentological, palynological or (micro)palaeontological approaches. In this thesis, results are presented of molecular organic geochemical investigations, aimed at palaeoenvi

  18. Corrosion Resistance of Ni-Based WC/Co Coatings Deposited by Spray and Fuse Process Varying the Oxygen Flow

    Science.gov (United States)

    Jiménez, H.; Olaya, J. J.; Alfonso, J. E.; Mtshali, C. B.; Pineda-Vargas, C. A.

    2017-08-01

    In this work, the effect of oxygen flow variation in the corrosion behavior of Ni-based WC/Co coatings deposited by spray and fuse process was investigated. The coatings were deposited on gray cast iron substrates using a Superjet Eutalloy thermal spraying gun. The morphology of the coatings was analyzed using scanning electron microscopy. The crystallographic phases were registered by x-ray diffraction (XRD), the diffraction patterns show the crystalline phases of the powder components with principal reflections for Ni and WC, the increase in flame temperature, due to the oxygen flow variation, generated amorphization in the nickel and an important crystallization of the planes (111) and (222) of WC as well as the decarburization of WC in W2C and W metallic. The corrosion behavior was investigated at room temperature in a 3.5% w/w aqueous solution of NaCl via potentiodynamic polarization. Electrochemical corrosion test showed that the coatings deposited under neutral flame conditions with an oxygen flow of 12.88 SCFH evidenced higher corrosion resistance. The chemical composition of the coatings and corrosion areas were analyzed by particle-induced x-ray emission, this technique permitting the corroboration of the decarburization process of WC determined by XRD and the formation of Cl structures.

  19. Sedimentary depositional environments of uranium and petroleum host rocks of the Jackson Group, south Texas

    Science.gov (United States)

    Dickinson, Kendell A.

    1976-01-01

    Determination of depositional environments in rocks of the Jackson Group of late Eocene age aids in the exploration for uranium and petroleum in south Texas. During deposition of the Jackson Group, conditions were similar to those existing along the modern Gulf Coast of Texas except for a less arid climate and a greater supply of volcanic sediment. Sedimentary depositional environments recognized in both the modern coast and the Jackson rocks, in order from sea toward land, are: shoreface, beach, lagoon and bay, and paludal. Sediment deposited in these environments in places is interbedded with or transected by fluvial sediment. Both uranium and petroleum are found in the shoreface, beach, and fluvial facies. These facies are characterized by permeable well-sorted sandstone, which is commonly overlain and underlain by less permeable mudstone. A typical vertical sequence in ascending order through a unit containing a beach sandstone facies is (1) lagoonal or paludal clay stone and siltstone, (2) crossbedded fine-grained beach sandstone which contains Ophiomorpha burrows and, which, in places, is locally interbedded with lacustrine or lagoonal mudstone, (3) weakly laminated beach sandstone which contains root impressions at the top and Ophiomorpha, and (4) lagoonal or paludal claystone and siltstone. Gulfward, the beach sandstone apparently grades into highly burrowed, generally finer grained, more poorly sorted, less porous shoreface rocks. The beach facies may include barrier island beaches and mainland beaches, some of which were probably cheniers. Beach facies sandstone units extend many miles along the depositional strike, which nearly parallels the present outcrop strike, but extend only a mile or two (2-3 km) normal to the depositional strike into the subsurface. Recognition of the various facies in outcrops and drill holes is necessary for determination of true stratigraphic relations and for aid in exploration for beach and fluvial sandstone favorable for

  20. Long-Term Fuid Flow Measurements From Widely Varied Oceanic Settings Elucidate Near-Surface Hydrologic Environments

    Science.gov (United States)

    Tryon, M. D.; Brown, K. M.

    2003-12-01

    The quantification of aqueous flux rates from various ocean floor environments has been a goal of numerous scientific programs for more than a decade with increasing focus on gas hydrate regions. Six years ago we developed the Chemical and Aqueous Transport (CAT) meter to collect long-term temporal records of low to moderate aqueous flow rates in sedimented ocean floor environments and, more specifically, to quantify to mass flux associated with the formation of gas hydrates. Since that time thirty of these instruments have been built and over a hundred deployments accomplished in a variety of hydrate and non-hydrate settings. We present here an overview of the results of these deployments and compare and contrast the flow records from these varied hydrological environments. Specific environments include: Gas Hydrates (Hydrate Ridge and the Eel River area on the Cascadia convergent margin, and Bush Hill in northern Gulf of Mexico), Hydrothermal (Japan's Sagami Bay and the incoming plate offshore Costa Rica's Nicoya Peninsula, TicoFlux area), and the tectonically active convergent margin off Nicoya and Osa. One of the most important outcomes of this research is the realization that fluid flow across the seabed/ocean interface is often dominated by shallow subsurface and oceanographic processes which vary significantly over time. These processes can be as simple as the diurnal pressure gradients caused by the rise and fall of tides to highly complex processes associated with the formation and transport of subsurface free gas. These processes have been both a boon and a bane to our research. Tidal oscillations have tended to mask the net flow in many very low flux settings. The high degree of spatial and temporal variation in some environments have revealed the extreme difficulty of quantifying the more widespread mass flux associated with the underlying tectonic processes. Yet, the nature of these variations have allowed us to better constrain the fundamental

  1. Helium-Charged Titanium Films Deposited by Pulsed Laser Deposition in an Electron-Cyclotron-Resonance Helium Plasma Environment

    Institute of Scientific and Technical Information of China (English)

    金钦华; 胡佩钢; 凌浩; 吴嘉达; 施立群; 周筑颖

    2003-01-01

    Titanium thin films incorporated with helium are produced by pulsed laser deposition in an electron cyclotron resonance helium plasma environment. Helium is distributed evenly in the film and a relatively high He/Ti atomic ratio (~ 20%) is obtained from the proton backscattering spectroscopy. This high concentration ofhelium leads to a surface blistering which is observed by scanning electron microscopy. Laser repetition rate has little influence on film characters. Substrate bias voltage is also changed for the helium incorporating mechanism study, and this is a helium ion implantation process during the film growth. Choosing suitable substrate bias voltage, one can avoid the damage produced by ion implantation, which is always present in general implantation case.

  2. Dust deposition in an oligotrophic marine environment: impact on the carbon budget

    Directory of Open Access Journals (Sweden)

    C. Guieu

    2014-01-01

    Full Text Available By bringing new nutrients and particles to the surface ocean, atmospheric deposition impacts biogeochemical cycles. The extent to which those changes are modifying the carbon balance in oligotrophic environments such as the Mediterranean Sea that receives important Saharan dust fluxes is unknown. DUNE project provides the first attempt to evaluate the changes induced in the carbon budget of an oligotrophic system after simulated Saharan dust wet and dry deposition events. Here we report the results for the 3 distinct artificial dust seeding experiments in large mesocosms that were conducted in the oligotrophic waters of the Mediterranean Sea in summer 2008 and 2010. Simultaneous measurements of the metabolic rates (C fixation, C respiration in the water column have shown that the dust deposition did not change drastically the metabolic balance as the tested waters remained net heterotroph (i.e. net primary production to bacteria respiration ratio < 1 and in some cases the net heterotrophy was even enhanced by the dust deposition. Considering the different terms of the carbon budget, we estimate that it was balanced with a dissolved organic carbon (DOC consumption of at least 10% of the initial stock. This corresponds to a fraction of the DOC stock of the surface mixed layer that consequently will not be exported during the winter mixing. Although heterotrophic bacteria were found to be the key players in the response to dust deposition, net primary production increased about twice in case of simulated wet deposition (that includes anthropogenic nitrogen and a small fraction of particulate organic carbon was still exported. Our estimated carbon budgets are an important step forward in the way we understand dust deposition and associated impacts on the oceanic cycles. They are providing knowledge about the key processes (i.e. bacteria respiration, aggregation that need to be considered for an integration of atmospheric deposition in marine

  3. Brood size manipulations in a spatially and temporally varying environment: male Tengmalm's owls pass increased reproductive costs to offspring.

    Science.gov (United States)

    Thomson, Robert L; Griesser, Michael; Laaksonen, Toni; Korpimäki, Erkki

    2014-10-01

    A key tool used to assess reproductive trade-offs in birds is brood size manipulation (BSM) experiments. Most BSM studies have examined the influence on short-term measures of reproductive output. Seldom evaluated are the effects on long-term fitness proxies under temporally or spatially varying environments. Unpredictable environments may affect reproductive trade-offs by altering the value of the brood or hampering optimization of reproductive effort. We reduced or enlarged broods of 140 male Tengmalm's owls Aegolius funereus by one chick during their first lifetime reproductive event. Males differed in age and bred in environments that varied in quality spatially (habitat structure) and temporally (abundance of main food). We measured the short-term (nestling number and condition) and long-term fitness proxies (survival, lifetime fledgling and recruits produced) until all experimental males disappeared from the population. BSMs did not affect fledgling number or condition, but in enlarged broods, offspring condition was lower in territories with a high proportion of agricultural fields. Importantly, no obvious impacts on long-term fitness proxies emerged; lifetime fledgling and recruit production of males did not differ between the BSM treatments. Thus, the primary caregiver (i.e. Tengmalm's owl males) passed increased reproductive costs to their offspring, which is in agreement with other studies investigating intergenerational reproductive trade-offs in species of intermediate lifespan. Reluctance to accept increased current reproductive costs in these systems highlights the potential for sexual conflict in bi-parental care systems in which one of the pair is the primary caregiver.

  4. Total N content and δ15N signatures in moss tissue for indicating varying atmospheric nitrogen deposition in Guizhou Province, China

    Science.gov (United States)

    Qu, Linglu; Xiao, Huayun; Guan, Hui; Zhang, Zhongyi; Xu, Yu

    2016-10-01

    Unsurprisingly, the amount of reactive nitrogen circulating annually on land has been doubled because of increasing anthropogenic activities. Exceedingly large amounts of reactive nitrogen (Nr) are likely to disrupt N dynamics and negatively impact the environment and human health. Guizhou Province, a major energy-producing province in southwest China, is suffering from serious long-term acid deposition. However, little work has been done to quantify the levels of atmospheric N deposition in this province, in which some ecologically vulnerable areas have resulted from rocky desertification. In this study, tissue N contents and δ15N signatures in 109 epilithic mosses were analyzed by the ordinary kriging (OK) interpolation technique to determine atmospheric N deposition. Moss N content (1.36-2.65%) showed a significant decrease from west to east, indicating that the spatial variance of TN deposition was the same as that of moss N content, with an average of 27.74 kg N ha-1 yr-1. Moss δ15N ranged from -5.89‰ to -0.72‰ and showed an opposite spatial variance compared with moss N contents. Negative δ15N indicated that the main sources for N deposition were urban sewage and agricultural NH3. According to Moss δ15N values, it could be concluded that NH4+-N and NO3--N were the main components of wet deposition, accounting for 52% and 44% of TN, respectively. The deposition fluxes were 14.49 kg N ha-1 yr-1 and 12.16 kg N ha-1 yr-1, respectively. Although the emission flux of NO3--N far exceeded that of NH4+-N, the amount of NH4+-N deposited on land was larger than that of NO3--N. N deposition in 99.6% of the province exceeded the critical load for terrestrial ecosystems. High N deposition is the main environmental problem facing Guizhou Province, and recommendations regarding regulatory strategies for mitigating atmospheric N pollution are urgently needed.

  5. Turnover of eroded soil organic carbon after deposition in terrestrial and aquatic environments

    DEFF Research Database (Denmark)

    Kirkels, Frédérique; Cammeraat, Erik; Kalbitz, Karsten

    The fate of eroded soil organic carbon (SOC) after deposition is a large uncertainty in assessing the impact of soil erosion on C budgets. Globally, large amounts of SOC are transported by erosion and a substantial part is transferred into adjacent inland waters, linking terrestrial and aquatic C...... cellulose. Physical and chemical soil properties and SOC molecular composition were assessed as potential controls on C turnover. SOC deposition in aquatic environments resulted in upto 3.5 times higher C turnover than deposition on downslope soils. Labile C inputs enlarged total CO2 emissions......, with the largest increase for aquatic conditions. Solid-state 13C NMR and FT-IR spectroscopy showed broad similarities in SOC molecular composition. Soil and SOC properties could not (yet) fully explain variation in SOC turnover between the sites. However, temporal trends in CO2 emissions clearly differed between...

  6. Reconstructing the Holocene depositional environments along the northern coast of Sfax (Tunisia): Mineralogical and sedimentological approaches

    Science.gov (United States)

    Lamourou, Ali; Touir, Jamel; Fagel, Nathalie

    2017-05-01

    A sedimentological and mineralogical study of sedimentary cores allowed reconstructing the evolution of depositional environments along the Northern coast of Sfax (Tunisia). The aim of this research work is to identify the factors controlling the sedimentation from the Holocene to the Present time. Three 30-m sediment cores collected by drilling at 30 m water depth were analyzed for their color, magnetic susceptibility signal, grain size by laser diffraction, organic matter content by loss of ignition, carbonate content by calcimetry and mineralogy by X-ray diffraction on bulk powder and clay <2 μm. They broadly present the same sedimentological and mineralogical features. Microscopical observations of petrographic slides allowed identifying six main sedimentary facies. Bulk mineralogical assemblages comprised clay minerals, quartz, calcite, gypsum and K-feldspars were examined. Considerable change was observed in the carbonate content that mimicked the bioclaste abundance and diluted the detrital minerals (clay minerals, quartz and feldspars). The gypsum mainly occurred in the lower sedimentary columns (SC12 and SC9) and in the upper/middle of core SC6. The clay fraction was made of a mixture of kaolinite, illite, smectite and palygorskite with no clear variation through core depth. Both grain-size parameters and magnetic susceptibility profile showed a sharp transition in the upper 2-5 m of the sedimentological columns. Coarse, sandy to gravely sediments characterized by a low magnetic susceptibility signal were replaced by fine bioclastic-rich clayey sediments. The analysis of vertical succession of depositional facies revealed a fluvial depositional environment (coastal plain) basically marked by fluvial channels and inundation plains at the bottom of all cores. However, core-top sediments recorded a littoral marine environment with sand depositions rich in gastropods, lamellibranches and algæ. Depositional facies, sedimentological and mineralogical

  7. Ants adjust their pheromone deposition to a changing environment and their probability of making errors.

    Science.gov (United States)

    Czaczkes, Tomer J; Heinze, Jürgen

    2015-07-07

    Animals must contend with an ever-changing environment. Social animals, especially eusocial insects such as ants and bees, rely heavily on communication for their success. However, in a changing environment, communicated information can become rapidly outdated. This is a particular problem for pheromone trail using ants, as once deposited pheromones cannot be removed. Here, we study the response of ant foragers to an environmental change. Ants were trained to one feeder location, and the feeder was then moved to a different location. We found that ants responded to an environmental change by strongly upregulating pheromone deposition immediately after experiencing the change. This may help maintain the colony's foraging flexibility, and allow multiple food locations to be exploited simultaneously. Our treatment also caused uncertainty in the foragers, by making their memories less reliable. Ants which had made an error but eventually found the food source upregulated pheromone deposition when returning to the nest. Intriguingly, ants on their way towards the food source downregulated pheromone deposition if they were going to make an error. This may suggest that individual ants can measure the reliability of their own memories and respond appropriately.

  8. Sedimentology, stratigraphy, and depositional environment of the Crystal Geyser Dinosaur Quarry, east-central Utah

    Science.gov (United States)

    Suarez, M.B.; Suarez, C.A.; Kirkland, J.I.; Gonzalez, Luis A.; Grandstaff, D.E.; Terry, D.O.

    2007-01-01

    The Crystal Geyser Dinosaur Quarry, near Green River, Utah, is located at the base of the Lower Cretaceous (Barremian) Yellow Cat Member of the Cedar Mountain Formation. The quarry preserves a nearly monospecific accumulation of a new basal therizinosauroid, Falcarius utahensis. We used field descriptions and petrographic analysis to determine the depositional environment and development of the quarry strata. Results of these analyses suggest that the quarry represents multiple episodes of bone accumulation buried by spring and overbank flood deposits. Evidence for these previously undescribed spring deposits includes calcite macroscopic structures within the quarry strata - such as pisolites and travertine fragments - and calcite micromorphologies - including radial-fibrous, feather, and scandulitic dendrite morphologies and tufa clasts. At least two episodes of bone incorporation are preserved in the quarry based on their stratigraphic position and lithologic associations. The unique depositional setting in and around the Crystal Geyser Dinosaur Quarry appears to have been favorable for the preservation of vertebrate fossils and provides insight into early Cretaceous environments in North America. Copyright ?? 2007, SEPM (Society for Sedimentary Geology).

  9. Thick pure palladium film with varied crystal structure electroless deposited from choline chloride–palladium chloride solution without the addition of reductant

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yurong; Li, Wei; Wang, Wenchang [School of Petrochemical Engineering, Key Laboratory of Fine Petrochemicals of Jiangsu Province, Changzhou University, Changzhou 213164 (China); Mitsuzak, Naotoshi [Qualtec Co., Ltd, Osaka 590-0906 (Japan); Bao, Weiliang [Department of Chemistry, Zhejiang University, Hanghzou 310058 (China); Chen, Zhidong, E-mail: chen13775646759@hotmail.com [School of Petrochemical Engineering, Key Laboratory of Fine Petrochemicals of Jiangsu Province, Changzhou University, Changzhou 213164 (China); School of Material Science and Engineering, Jiangsu Key Laboratory of Material Surface Technology, Changzhou University, Changzhou 213164 (China)

    2015-07-01

    Immersion deposition procedure was applied to achieve thick pure palladium films with thickness up to about 3 μm from choline chloride (ChCl)–palladium chloride (PdCl{sub 2}) aqueous solution without addition of reductant at 60 °C. Using X-ray diffraction and scanning electron microscope, it was confirmed that Pd films with different crystal orientations and morphology were obtained just by varying the immersion time, and Pd (111) crystal orientation predominated over other crystal orientations during the initial deposition procedure, while (220) conquered (111) about 45 min later. ChCl performing as a reductant facilitated the growth of thick Pd film free of reductant. The immersion deposition of Pd followed the mechanism of replacement reaction accompanying with autocatalyzed reaction and autocatalyzed reaction predominating over replacement reaction. The results revealed that Pd films prepared from ChCl–PdCl{sub 2} solution had excellent properties on solderability and corrosion resistance. - Highlights: • Thick pure Pd film was obtained from ChCl–PdCl{sub 2} aqueous solution without reductant. • Different crystal orientations and morphology of Pd films were achieved. • Immersion time determined the morphology of Pd films. • The mechanism of sustained deposition of Pd on Ni–P surface was deduced.

  10. Maturation, constitution and depositional environment of the coals from Makardhokada area, Nagpur District, Maharashtra

    Energy Technology Data Exchange (ETDEWEB)

    Sarate, O.S. [Birbal Sahni Institute of Paleobotany, Lucknow (India)

    2007-12-15

    Recent sub-surface investigations have proved the existence of coal deposits in Makardhokada area of Nagpur District, Maharashtra. Structurally, Makardhokada area represents the western extension of Umrer coalfield. As far as the economic potentialities of these coal deposits are concerned, out of the six seams intersected, only four viz. Seam I, II, IV and V have attained workable thickness of more than a metre. The maceral constitution and rank estimations have been considered as the parameters to interpret the depositional environment and economic importance of these coal deposits. The maceral study suggests that the coal of seam I contains a mixture of all the three coal types i.e. vitric (Vitrinite rich), fusic (Inertinite rich) and mixed (Vitrinite + Inertinite rich). However, the seams II and IV are constituted by fusic and mixed coal types. Seam V contains both the vitric and mixed coal types. The maturation (reflectance) studies have indicated low vitrinite reflectivity (R{sub 0} max %) of 0.42-0.53%, which suggests that the coals have attained sub-bituminous C to high volatile bituminous C stage of the rank. The coal constitution suggests frequent floods at the depositional site and alternate dry oxidizing and cold climatic seasonal changes caused the formation of vitric and fusic coal types.

  11. Subaqueous environment and volcanic evolution of the Late Cretaceous Chelopech Au-Cu epithermal deposit, Bulgaria

    Science.gov (United States)

    Chambefort, Isabelle; Moritz, Robert

    2014-12-01

    A detailed field and petrographic study constrains the volcanic evolution and environment setting of the volcano-sedimentary-hosted Chelopech Cu-Au epithermal deposit, Bulgaria. Magmatic activity and associated high-sulfidation epithermal mineralization occurred at about 91 Ma in the Panagyurishte ore district of the Eastern European Banat-Timok-Srednogorie metallogenic belt. Volcanic and hydrothermal activity took place in a complex subaqueous setting, resulting in the intercalation of quartz sandstone with andesitic volcanic and volcaniclastic breccia. There are also hypabyssal andesite intrusion, phreatomagmatic breccia and interbeds of pyroclastic, oolithic and bioclastic rocks. The presence of altered cerebroid ooid-bearing sedimentary units characteristic of salty environment is in accordance with a lagoon environment predating the mineralization at Chelopech. Four principal stages of evolution for the Chelopech district are proposed based on field and petrographic observations. Initial volcanism occurred in a lake or in a coastal, shallow lagoon environment above crystalline basement. The Chelopech "phreatomagmatic" breccia and subsurface andesites were emplaced at this time. Subsequent hydrothermal activity produced the different hydrothermal breccia types, advanced argillic and quartz-phyllic alteration, and Au-Cu vein and replacement mineralization. The end of volcanism and hydrothermal activity was associated with opening of a pull-apart basin that covered the Chelopech environment with a sedimentary flysch. Tertiary compression faulting juxtaposed various rocks and tilted the ore deposit during the Alpine orogeny.

  12. Temperature varying photoconductivity of GeSn alloys grown by chemical vapor deposition with Sn concentrations from 4% to 11%

    Science.gov (United States)

    Hart, John; Adam, Thomas; Kim, Yihwan; Huang, Yi-Chiau; Reznicek, Alexander; Hazbun, Ramsey; Gupta, Jay; Kolodzey, James

    2016-03-01

    Pseudomorphic GeSn layers with Sn atomic percentages between 4.5% and 11.3% were grown by chemical vapor deposition using digermane and SnCl4 precursors on Ge virtual substrates grown on Si. The layers were characterized by x-ray diffraction rocking curves and reciprocal space maps. Photoconductive devices were fabricated, and the dark current was found to increase with Sn concentration. The responsivity of the photoconductors was measured at a wavelength of 1.55 μm using calibrated laser illumination at room temperature and a maximum value of 2.7 mA/W was measured for a 4.5% Sn device. Moreover, the responsivity for higher Sn concentration was found to increase with decreasing temperature. Spectral photoconductivity was measured using Fourier transform infrared spectroscopy. The photoconductive absorption edge continually increased in wavelength with increasing tin percentage, out to approximately 2.4 μm for an 11.3% Sn device. The direct band gap was extracted using Tauc plots and was fit to a bandgap model accounting for layer strain and Sn concentration. This direct bandgap was attributed to absorption from the heavy-hole band to the conduction band. Higher energy absorption was also observed, which was thought to be likely from absorption in the light-hole band. The band gaps for these alloys were plotted as a function of temperature. These experiments show the promise of GeSn alloys for CMOS compatible short wave infrared detectors.

  13. Investigating near-road particle number concentrations along a busy urban corridor with varying built environment characteristics

    Science.gov (United States)

    Xu, Junshi; Wang, An; Hatzopoulou, Marianne

    2016-10-01

    This study aimed at capturing the determinants of near-road concentrations of ultrafine particles (UFP) using linear mixed-effects models, investigating the effects of meteorology, built environment, and traffic. In addition, the differences in the levels of UFP between both sides of the road were investigated. To reach these objectives, field measurements were conducted on 16 weekdays in the months of March and April 2015, along Papineau Avenue, a high-volume street in Montreal, Canada. Four sites were identified varying in land use, building height, and road characteristics. Air quality measurements were conducted at each location (on both sides of the road) for two consecutive hours, at four different times during the day and repeated four times, leading to a total of 16 visits per location. Traffic volume and composition was also recorded. On-site meteorological variables including wind speed, wind direction, temperature and relative humidity were collected using a portable weather station. Linear mixed-effects models with random intercept were developed for both dependent variables: the natural logarithm of the mean UFP concentration and the difference in UFP concentrations between two sides of the road. Lower temperatures and wind speeds were associated with increased UFP concentrations. Winds orthogonal to the road tended to increase UFP concentrations as well as the differences between both sides of the road. Finally, built environment variables such as the presence of open areas and buildings on both sides of the road, had a positive influence on the difference between UFP on the two sides.

  14. Investigation on deposition condition, sedimentary environment and genesis of Mandan and Deh-Now bauxite deposits, Dehdasht area, Kohgiloye and Boyer-Ahmad province: using mineralogical studies

    Directory of Open Access Journals (Sweden)

    Alireza Zarasvandi

    2011-04-01

    Full Text Available The Mandan and Deh-Now bauxite deposits are located 40 km northeast of Dehdasht in Kohgiloye and Boyer-Ahmad province in the Zagros simply folded belt. The deposits were formed in the oldest rocks of the area of late Cretaceous age. The bauxite horizon is situated between Sarvak and Ilam formations. The aim of this study is to determine the mineralogy and texture relations of the deposits in order to determine the environment and status of bauxite mineralization. In this way, samples were selected from these bauxite deposits for mineralogical studies based on microscopic and XRD techniques. The bauxite horizon in the Mandan deposit consists of white, gray, black, pisolitic, red and yellow bauxites. The sequence was repeated in the Deh-Now without black and gray bauxites. Mineralogy is similar in all bauxitic layers and the main textures are pisolitic-ooide, ooide-spheroid, pisolitic, pelitomorphic and pseoudomorphic. Bohmite, diaspore, kaolinite and calcite are the most important minerals in both bauxitic layers of the Mandan and Deh-Now deposits. Due to bohmite mineralization in the study area, erosional and intense weathering environment in the Touronian-Cenomanian could be suggested for the deposition of bauxite in these deposits. Existence of interclasts in the pisolites and ooides indicate that these bauxites were transformed from the primary in situ environment to karstic sedimentary basin as authigenic origin. These studies indicate that there are two mineralized facies with different environmental status: (1 oxidation facies with bohmite, diaspore, kaolinite and hematite minerals and (2 reduced facies with pyrite, diaspore and chlorite mineralization. The lack of reduced condition at the Deh-Now deposit shows that the deposit formed only in oxidation status.

  15. Extended stratigraphy, palynology and depositional environments record the initiation of the Himalayan Gyirong Basin (Neogene China)

    Science.gov (United States)

    Xu, Ya-Dong; Zhang, Ke-Xin; Wang, Guo-Can; Jiang, Shang-Song; Chen, Fen-Ning; Xiang, Shu-Yuan; Dupont-Nivet, Guillaume; Hoorn, Carina

    2012-01-01

    Here we report new sedimentological and paleontological data from a 603.5 m thick Neogene sequence (Woma section) in the Gyirong Basin, a basin induced by east-west extension in the Himalayas of southern Tibet. We document the conglomeratic Danzengzhukang Formation, at the base of the section, and the overlying finer grained Woma Formation that includes a Hipparion fauna. Based on stratigraphic correlations and earlier thermochronology and magnetostratigraphic results, we bracket the depositional age of this section between 10.8 Ma and 1.7 Ma. Lithology, paleo-current directions and provenance analysis, together with palynological and paleontological data, have revealed three depositional environments for the deposition of the studied section. (1) Alluvial-fan to braided river environments with ESE transport directions (Danzengzhukang Formation, coniferous- and broad-leaved mixed forest. (2) Lacustrine dominated conditions (Lower Woma Formation, ˜7.2 to 3.2 Ma) with WSW transport directions were associated with locally warm and humid environments in the low-lying areas while input from a new source area suggests the presence of a high-altitude, cold and arid deciduous coniferous-leaved forests. (3) A fan delta dominated environment (Upper Woma Formation, 3.2 to >1.7 Ma) with increased denudation and WSW paleo-currents was associated with a deciduous coniferous and broad-leaved mixed forest that suggests an increase in climate variability. Our data indicate that the Gyirong Basin was under overall warm and humid conditions throughout most of its history, in agreement with high-resolution oxygen and carbon isotope data collected from the same section (this issue). We interpret our warm climate in the Gyirong Basin to reflect the prevalence of the monsoonal influence and the distal pollen sources to result from orographic effects.

  16. Imaging Quaternary glacial deposits and basement topography using the transient electromagnetic method for modeling aquifer environments

    Science.gov (United States)

    Simard, Patrick Tremblay; Chesnaux, Romain; Rouleau, Alain; Daigneault, Réal; Cousineau, Pierre A.; Roy, Denis W.; Lambert, Mélanie; Poirier, Brigitte; Poignant-Molina, Léo

    2015-08-01

    Aquifer formations along the northern shore of the Saint-Lawrence River in Quebec (Canada) mainly consist of glacial and coastal deposits of variable thickness overlying Precambrian bedrock. These deposits are important because they provide the main water supply for many communities. As part of a continuing project aimed at developing an inventory of the groundwater resources in the Charlevoix and Haute-Côte-Nord (CHCN) regions of the province of Quebec in Canada, the central loop transient electromagnetic (TEM) method was used to map the principal hydrogeological environments in these regions. One-dimensional smooth inversion models of the TEM soundings have been used to construct two-dimensional electrical resistivity sections, which provided images for hydrogeological validation. Electrical contour lines of aquifer environments were compared against available well logs and Quaternary surface maps in order to interpret TEM soundings. A calibration table was achieved to represent common deposits and basements. The calibration table was then exported throughout the CHCN region. This paper presents three case studies; one in the Forestville site, another in the Les Escoumins site and the other in the Saint-Urbain site. These sites were selected as targets for geophysical surveys because of the general lack of local direct hydrogeological data related to them.

  17. Doomed pioneers: Gravity-flow deposition and bioturbation in marine oxygen-deficient environments

    Science.gov (United States)

    Föilmi, Karl B.; Grimm, Kurt A.

    1990-11-01

    Isolated horizons of Thalassinoides and Gyrolithes burrows appear in exclusive association with gravity-flow deposits within sequences of nonbioturbated hernipelagic sedimentary rocks of the Miocene Monterey Formation of California and the Oligocene-Miocene San Gregorio Formation of Baja California. These burrowed levels are not associated with other ichnogenera such as Zoophycos and Chondrites. We infer a causal relation between gravity flow deposition and the presence of Thalassinoides and Gyrolithes and suggest that these gravity flows entrained thalassinidean crustacea. Upon deposition in oxygen-deficient environments, the surviving borrowers reworked substantial quantities of aminated, commonly organic-rich sediments in an environment from which they were previously excluded. The persistence of or the ecologically rapid return to oxygen-depleted conditions limited the survival time and ecological complexity of the transported infaunal dwellers and rendered them doomed pioneers. Ecological and physiological data support this hypothesis: thalassinidean crustacea have the capability to endure turbulent transport and survive up to 5-7 days of anoxia without being severely limited in their biological activities. The accurate recognition of doomed pioneer trace-fossil assemblages as ephemeral ecological phenomena in otherwise laminated successions may contribute to a better understanding and interpretation of paleo-oxygen levels and basin history.

  18. Cooling Strategies for Vane Leading Edges in a Syngas Environment Including Effects of Deposition and Turbulence

    Energy Technology Data Exchange (ETDEWEB)

    Ames, Forrest [Univ. of North Dakota, Grand Forks, ND (United States); Bons, Jeffrey [Univ. of North Dakota, Grand Forks, ND (United States)

    2014-09-30

    levels found on in service vanes (Bons, et al., 2001, up to 300 microns) flow blockage in first stage turbine nozzles can easily reach 1 to 2 percent in conventional turbines. Deposition levels in syngas fueled gas turbines are expected to be even more problematic. The likelihood of significant deposition to the leading edge of vanes in a syngas environment indicates the need to examine this effect on the leading edge cooling problem. It is critical to understand the influence of leading edge geometry and turbulence on deposition rates for both internally and showerhead cooled leading edge regions. The expected level of deposition in a vane stagnation region not only significantly changes the heat transfer problem but also suggests that cooling arrays may clog. Addressing the cooling issue suggests a need to better understand stagnation region heat transfer with realistic roughness as well as the other variables affecting transport near the leading edge. Also, the question of whether leading edge regions can be cooled internally with modern cooling approaches should also be raised, thus avoiding the clogging issue. Addressing deposition in the pressure side throat region of the nozzle is another critical issue for this environment. Issues such as examining the protective effect of slot and full coverage discrete-hole film cooling on limiting deposition as well as the influence of roughness and turbulence on effectiveness should be raised. The objective of this present study is to address these technical challenges to help enable the development of high efficiency syngas tolerant gas turbine engines.

  19. Geochemistry and depositional environments of Paleocene-Eocene phosphorites: Metlaoui Group, Tunisia

    Science.gov (United States)

    Garnit, Hechmi; Bouhlel, Salah; Jarvis, Ian

    2017-10-01

    The Late Paleocene-Early Eocene phosphorites of the Metlaoui Group in Tunisia are a world-class phosphate resource. We review the characteristics of phosphorites deposited in three areas: the Northern Basins; Eastern Basins; and Gafsa-Metlaoui Basin. Comprehensive new bulk rock elemental data are presented, together with complementary mineralogical and mineral chemical results. Carbonate fluorapatite (francolite) constitutes the dominant mineral phase in the deposits. Phosphorite samples are enriched in Cd, Sr, U, rare-earth elements and Y, together with environmentally diagnostic trace elements that provide detrital (Cr, Zr), productivity (Cu, Ni, Zn) and redox (Mo, V) proxies. Suboxic bottom-water conditions predominated, with suboxic to anoxic porewaters accompanying francolite precipitation. Phosphorite deposition occurred under increasingly arid climate conditions, accompanying global Paleocene-Eocene warming. The Northern Basins show the strongest Tethys Ocean influence, with surface seawater rare-earth element signatures consistently developed in the phosphorites. Bed-scale compositional variation indicates relatively unstable environmental conditions and episodes of sediment redeposition, with varying detrital supply and a relatively wet local climate. Glauconitic facies in the Northern Basins and the more isolated evaporite-associated phosphorites in the dryer Eastern Basins display the greatest diagenetic influences. The phosphorite - organic-rich marl - diatom-bearing porcelanite facies association in the Gafsa-Metlaoui Basin represents the classic coastal upwelling trinity. Modified Tethyan waters occurred within the Basin during phosphorite deposition, with decreasing marine productivity from NW to SE evidenced by systematically falling enrichment factors for Cu, Ni, Cd and Zn in the phosphorites. Productivity declined in concert with increasing basin isolation during the deposition of the commercial phosphorite beds in the latest Paleocene to earliest

  20. Substrate-Versatile Approach to Robust Antireflective and Superhydrophobic Coatings with Excellent Self-Cleaning Property in Varied Environments.

    Science.gov (United States)

    Ren, Tingting; He, Junhui

    2017-09-20

    Robust antireflective and superhydrophobic coatings are highly desired in wide applications, such as optical devices, solar cell panels, architectural and automotive glasses, lab-on chip systems, and windows for electronic devices. Meanwhile, simple, low-cost, and substrate-versatile fabrication is also essential toward real applications of such coatings. Herein, we developed a substrate-versatile strategy to fabricate robust antireflective and superhydrophobic coatings with excellent self-cleaning property in varied environments, including air and oil and after oil contamination. A mixed ethanol suspension, which consists of 1H,1H,2H,2H-perfluorooctyltriethoxysilane modified dual-sized silica nanoparticles and acid-catalyzed silica precursor, was first synthesized. The acid-catalyzed silica precursor could help to form a highly cross-linked silica network by connecting the silica nanoparticles, thus significantly enhancing the robustness of coatings. The as-prepared coatings were able to withstand a water drop impact test, sand abrasion test, tape adhesion test, and knife and pencil scratching tests. More importantly, it was also found that the wettability and self-cleaning property of coatings after oil contamination were surprisingly different from those in air and oil. These observations are explainable by the alteration of interface; i.e., the alteration of interface has significant effects on the functional properties of coatings. Additionally, the mixed suspension could be sprayed onto various hard and soft substrates including glass, polyethylene terephthalate (PET), polycarbonate (PC), and poly(methyl methacrylate) (PMMA), opening up a feasible route toward varied practical applications in solar cell panels, optical devices, architectural and automotive glasses, droplet manipulators, and fluid control.

  1. ENVIRONMENT PROTECTION THROUGH DETECTION OF HOT SPOTS USING THERMOGRAPHY IN COAL DEPOSITS BEFORE SELF IGNITION

    Directory of Open Access Journals (Sweden)

    Alina DINCĂ

    2009-12-01

    Full Text Available In this paper is presented a way to contribute to the environmental protection when it comes to coal which waits in big deposits to be burned for energy production. Because of certain parameters, in some places, the deposited coal could overheat and self ignite, thus loosing its caloric properties and even lead to fire. In this case the losses could be even higher, and the effect on the environment even worse. In order to prevent this self ignition to happen, an infrared camera can be mounted on a system, and the camera together with software which interprets the thermographic images, can alarm the personnel who is in charge with coal surveillance that the coal will ignite unless they take immediate measures. Also, there will be presented the limits we have found by now in the way of finalizing the application.

  2. Measuring and modelling the radiological impact of a phosphogypsum deposition site on the surrounding environment.

    Science.gov (United States)

    Bituh, Tomislav; Petrinec, Branko; Skoko, Božena; Vučić, Zlatko; Marović, Gordana

    2015-03-01

    Phosphogypsum (PG) is a waste product (residue) from the production of phosphoric acid characterized by technologically enhanced natural radioactivity. Croatia's largest PG deposition site is situated at the edge of Lonjsko Polje Nature Park, a sensitive ecosystem possibly endangered by PG particles. This field study investigates two aspects relevant for the general radiological impact of PG: risk assessment for the environment and risk assessment for occupationally exposed workers and local inhabitants. Activity concentrations of natural radionuclides ((238)U, (235)U, (232)Th, (226)Ra, (210)Pb, and (40)K) were measured in the PG (at the deposition site), soil, and grass samples (in the vicinity of the site). The ERICA Assessment Tool was used to estimate the radiological impact of PG particles on non-human biota of the Lonjsko Polje Nature Park. The average annual effective dose for occupationally exposed workers was 0.4 mSv which was within the worldwide range.

  3. Determination of hydraulic conductivity from grain-size distribution for different depositional environments.

    Science.gov (United States)

    Rosas, Jorge; Lopez, Oliver; Missimer, Thomas M; Coulibaly, Kapo M; Dehwah, Abdullah H A; Sesler, Kathryn; Lujan, Luis R; Mantilla, David

    2014-01-01

    Over 400 unlithified sediment samples were collected from four different depositional environments in global locations and the grain-size distribution, porosity, and hydraulic conductivity were measured using standard methods. The measured hydraulic conductivity values were then compared to values calculated using 20 different empirical equations (e.g., Hazen, Carman-Kozeny) commonly used to estimate hydraulic conductivity from grain-size distribution. It was found that most of the hydraulic conductivity values estimated from the empirical equations correlated very poorly to the measured hydraulic conductivity values with errors ranging to over 500%. To improve the empirical estimation methodology, the samples were grouped by depositional environment and subdivided into subgroups based on lithology and mud percentage. The empirical methods were then analyzed to assess which methods best estimated the measured values. Modifications of the empirical equations, including changes to special coefficients and addition of offsets, were made to produce modified equations that considerably improve the hydraulic conductivity estimates from grain size data for beach, dune, offshore marine, and river sediments. Estimated hydraulic conductivity errors were reduced to 6 to 7.1 m/day for the beach subgroups, 3.4 to 7.1 m/day for dune subgroups, and 2.2 to 11 m/day for offshore sediments subgroups. Improvements were made for river environments, but still produced high errors between 13 and 23 m/day.

  4. Determination of hydraulic conductivity from grain-size distribution for different depositional environments

    KAUST Repository

    Rosas, Jorge

    2013-06-06

    Over 400 unlithified sediment samples were collected from four different depositional environments in global locations and the grain-size distribution, porosity, and hydraulic conductivity were measured using standard methods. The measured hydraulic conductivity values were then compared to values calculated using 20 different empirical equations (e.g., Hazen, Carman-Kozeny) commonly used to estimate hydraulic conductivity from grain-size distribution. It was found that most of the hydraulic conductivity values estimated from the empirical equations correlated very poorly to the measured hydraulic conductivity values with errors ranging to over 500%. To improve the empirical estimation methodology, the samples were grouped by depositional environment and subdivided into subgroups based on lithology and mud percentage. The empirical methods were then analyzed to assess which methods best estimated the measured values. Modifications of the empirical equations, including changes to special coefficients and addition of offsets, were made to produce modified equations that considerably improve the hydraulic conductivity estimates from grain size data for beach, dune, offshore marine, and river sediments. Estimated hydraulic conductivity errors were reduced to 6 to 7.1m/day for the beach subgroups, 3.4 to 7.1m/day for dune subgroups, and 2.2 to 11m/day for offshore sediments subgroups. Improvements were made for river environments, but still produced high errors between 13 and 23m/day. © 2013, National Ground Water Association.

  5. Geochemical and diatom records of recent changes in depositional environment of a tropical wetland, central west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Pande, A.; Nayak, G.N.; Prasad, V.; PrakashBabu, C

    Two mudflat sediment cores collected from a sub-channel (S-61) and the main channel (S-60) of a tropical wetland, along central west coast of India, were investigated for recent changes in depositional environment using geochemical (sediment grain...

  6. Rare earth element geochemistry of shallow carbonate outcropping strata in Saudi Arabia: Application for depositional environments prediction

    Science.gov (United States)

    Eltom, Hassan A.; Abdullatif, Osman M.; Makkawi, Mohammed H.; Eltoum, Isam-Eldin A.

    2017-03-01

    The interpretation of depositional environments provides important information to understand facies distribution and geometry. The classical approach to interpret depositional environments principally relies on the analysis of lithofacies, biofacies and stratigraphic data, among others. An alternative method, based on geochemical data (chemical element data), is advantageous because it can simply, reproducibly and efficiently interpret and refine the interpretation of the depositional environment of carbonate strata. Here we geochemically analyze and statistically model carbonate samples (n = 156) from seven sections of the Arab-D reservoir outcrop analog of central Saudi Arabia, to determine whether the elemental signatures (major, trace and rare earth elements [REEs]) can be effectively used to predict depositional environments. We find that lithofacies associations of the studied outcrop (peritidal to open marine depositional environments) possess altered REE signatures, and that this trend increases stratigraphically from bottom-to-top, which corresponds to an upward shallowing of depositional environments. The relationship between REEs and major, minor and trace elements indicates that contamination by detrital materials is the principal source of REEs, whereas redox condition, marine and diagenetic processes have minimal impact on the relative distribution of REEs in the lithofacies. In a statistical model (factor analysis and logistic regression), REEs, major and trace elements cluster together and serve as markers to differentiate between peritidal and open marine facies and to differentiate between intertidal and subtidal lithofacies within the peritidal facies. The results indicate that statistical modelling of the elemental composition of carbonate strata can be used as a quantitative method to predict depositional environments and regional paleogeography. The significance of this study lies in offering new assessments of the relationships between

  7. Performance of sulfation and nitration plates used to monitor atmospheric pollutant deposition in a real environment

    Energy Technology Data Exchange (ETDEWEB)

    Noel, D.; Hechler, J.; Roberge, H.

    1989-01-01

    Sulfation and nitration plates were exposed outdoors for various periods of time to evaluate their performance in a real environment. These passive monitors are used to estimate the deposition of pollutants on metallic surfaces, and thus to evaluate the influence of the atmosphere on the corrosion. Single-column ion chromatography was used to determine the quantity of anions absorbed on the plates. This technique is better than other analytical procedures such as turbidimetry or colorimetry because passive monitors exposed in an atmosphere with a low degree of pollution can be analyzed without preconcentration. However, the pH of the sample to be injected on the chromatographic column must be adjusted to between 6.0 and 12.0 in order to obtain reproducible sulfate values. For sulfation plates, the additivity of the deposition process is excellent for a period of exposure up to 3 months, with a reproducibility of about 2%. For nitration plates, the deposition process is not cumulative due to a physical change of the monitor during exposure. The correlation between the amounts of sulfate found on sulfation snd nitration plates was also examined. 16 refs., 6 figs., 5 tabs.

  8. Depositional environments of Laborcita Formation (Wolfcampian), northern Sacramento Mountains, New Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Fly, S.H. III

    1986-03-01

    Depositional environments that change dramatically over short lateral distances are represented by exposures of the Laborcita Formation. A siliclastic source area lay to the east and southeast, in the Pedernal Mountains. To the west, a shallow marine sea filled the orogrande basin. Alternating cycles of marine and nonmarine sedimentation resulted from fan-delta lobe shifting and eustatic sea level movements. In clear-water areas not affected by fan-deltaic sedimentation, deposits become increasingly calcareous. Various carbonate facies resulted from organisms adapting to changing environmental conditions. Mud-cracked algal mats, digitate algal stromatolites, and small phylloid red algal mounds and rhodoliths indicate deposition in shallow-water subtidal to supratidal settings. Large buildups (20 m thick) of phylloid green algae associated with abundant submarine cement occurred in a position near the edge of the narrow shelf. Widespread skeletal detritus beds overlie and extend hundreds of meters away from the massive buildups. Influx of terrigenous mud and silt in advance of a prograding fan-delta system terminated growth of the buildups. The next transgression is represented by a carbonate grainstone exhibiting characteristics of shallow-water marine, storm-dominated shelf bars. The shelf bars migrated in a northwest-southeast direction.

  9. A new approach to determine the phosphogypsum spread from the deposition site into the environment.

    Science.gov (United States)

    Bituh, Tomislav; Vučić, Zlatko; Marović, Gordana; Prlić, Ivica

    2013-10-15

    Phosphogypsum (PG), a waste product in phosphate fertilizer production, is characterized by technically enhanced natural radioactivity. The presented investigation was performed on a PG deposition site in Croatia. A new approach in the determination of the spread of PG particles from the deposition site into the environment based on the PG particle radioactivity measurements is suggested and explained. The stationary diffusion model was assumed and employed to describe long term PG particle transfer into the surroundings. The advantage of this method is that it requires a minimal number of measurement locations and offers a realistic and reliable distribution of PG particles. The mass concentration of PG particles decreased to the distance of about 3m, at most up to 10 m from the deposition site edge. The results indicate that a unique mechanism of particle transport exists and the migration of PG particles by surface water is the dominant way of their spread. The particle current deduced from the measurements was very low, approximately 4.05 × 10(-2)kg/h, and the migration coefficient was approximately 1.69 × 10(-5)m(2)/h. The obtained results confirmed the initial hypothesis of the stationarity of the migration process, reached within about 6 years.

  10. REE geochemical characteristics and depositional environment of the black shale-hosted Baiguoyuan Ag-V deposit in Xingshan, Hubei Province, China

    Institute of Scientific and Technical Information of China (English)

    YANG Boyong; HU Bin; BAO Zhengyu; ZHANG Zhaogan

    2011-01-01

    By means of techniques such as inductively coupled plasma-mass spectrometry (ICP-MS) and X-ray fluorescence spectrometry (XRF), REE geochemical characteristics and depositional environment of the black shales in Baiguoyuan Ag-V deposit, Xingshan, Hubei Province, were studied in this work. The black shales in a typical TC5 profile of Doushantuo Formation of upper Sinian period were obviously enriched in REE, especially in LREE. The REE patterns of the investigated samples normalized by Post Archean Australian Shale (PAAS) showed a flat or slight rightward inclination. The characteristic elements, their ratio and correlation diagrams showed that it should be hot-water deposit and the black shale in the study area was of a sedimentary origin. Redox sensitive metal elements pattern, trace elements index measurement in anoxic environment, Ce anomaly and δEu negative anomaly showed that the deposit environment of the black shales was a reducing and anoxic one and a slight change of the sea level could be identified. The samples relatively focused on the superimposed area of sedimentary rock and basalt in the diagram of La/Yb-ΣREE and La/Yb-Ce/La. So there might be accession of hot-water sedimentation during the period of the formation of the black rock series, mostly in normal terrigenous sedimentation with the participation of deep hot-water deposit.

  11. Depositional environment and organic geochemistry of the Upper Permian Ravenfjeld Formation source rock in East Greenland

    Energy Technology Data Exchange (ETDEWEB)

    Christiansen, F.G.; Piasecki, S.; Stemmerik, L. (Geologoical Survey of Greenland, Copenhagen (Denmark)); Telnaes, N. (Norsk Hydro Research Center, Bergen (Norway))

    1993-09-01

    The Upper Permian Ravnefjeld Formation in East Greenland is composed of shales that laterally pass into carbonate buildups and platforms of the Wegener Halvo Formation. The Ravnefjeld Formation is subdivided into five units that can be traced throughout the Upper Permian depositional basin. Two of the units are laminated and organic rich and were deposited under anoxic conditions. They are considered good to excellent source rocks for liquid hydrocarbons with initial average TOC (total organic carbon) values between 4 and 5% and HI (hydrogen index) between 300 and 400. The cumulative source rocks are separated and enclosed by three units of bioturbated siltstone with a TOC of less than 0.5% and an HI of less than 100. These siltstones were deposited under relatively oxic conditions. The organic geochemistry of the source rocks is typical for marine source rocks with some features normally associated with carbonate/evaporite environments [low Pr/Ph (pristane/phytane), low CPI (carbon preference index), distribution of tricyclic and pentacyclic terpanes]. The establishment of anoxic conditions and subsequent source rock deposition was controlled by eustatic sea level changes. The subenvironment (paleogeographic setting, influx of carbonate material, water depth, salinity) has some influence on a number of bulk parameters [TOC-HI relations, TOC-TS (total sulfur) relations] and, in particular, biomarker parameters such as Pr/Ph and terpane ratios. All the basal shales or shales in the vicinity of carbonate buildups of platforms are characterized by low Pr/Ph, high C[sub 23] tricyclic terpanes, and high C[sub 35] and C[sub 33] hopanes. 52 refs., 20 figs., 3 tabs.

  12. Plasma environment during hot cathode direct current discharge plasma chemical vapor deposition of diamond films

    Institute of Scientific and Technical Information of China (English)

    朱晓东; 詹如娟; 周海洋; 胡敏; 温晓辉; 周贵恩; 李凡庆

    1999-01-01

    The plasma characteristics have been investigated in situ by using optical emission spectroscopy (OES) and the Langmuir probe during hot cathode direct current discharge plasma chemical vapor deposition of diamond films. The changes of atomic H and CH radical in the ground state have been calculated quantitatively according to the results of OES and the Langmuir probe measurement as discharge current density varied. It is shown that atomic H and CH radicals both in the ground state and in the excited state increase with the enhancement of the discharge current density in the plasma. The electron density and CH emission intensity increase linearly with the enhancement of discharge current densities. The generation of different carbon-containing radicals is related to the elevation of electron temperature. Combining the growth process of diamond films and the diagnostic results, it is shown that atomic H in the excited state may improve the diamond growth efficiently, and the increase of electron temperat

  13. Electrical conductivity mechanisms in zinc oxide thin films deposited by pulsed laser deposition using different growth environments

    Energy Technology Data Exchange (ETDEWEB)

    Heluani, S.P. [Laboratorio de Fisica del Solido, Departamento de Fisica, Facultad de Ciencias Exactas y Tecnologia, Universidad Nacional de Tucuman (Argentina)]. E-mail: sperez@herrera.unt.edu.ar; Braunstein, G. [Department of Physics, University of Central Florida, Orlando, FL 32816 (United States); Villafuerte, M. [Laboratorio de Fisica del Solido, Departamento de Fisica, Facultad de Ciencias Exactas y Tecnologia, Universidad Nacional de Tucuman (Argentina); Simonelli, G. [Laboratorio de Fisica del Solido, Departamento de Fisica, Facultad de Ciencias Exactas y Tecnologia, Universidad Nacional de Tucuman (Argentina); Duhalde, S. [Laboratorio de Ablacion Laser, Facultad de Ingenieria, Universidad de Buenos Aires (Argentina)

    2006-12-05

    The mechanisms of electrical conduction in zinc oxide thin films, grown by pulsed laser deposition, have been investigated as a function of preparation conditions. The films were deposited on glass and silicon nitride coated silicon, using oxygen rich, oxygen deficient, or nitrogen atmospheres. The substrates were held at 473 K during deposition, and subsequently cooled down to room temperature in oxygen rich atmosphere of 4 Pa, or oxygen deficient atmosphere of 2 x 10{sup -3} Pa. Films deposited and cooled in an oxygen deficient atmosphere exhibited very high donor concentration, originated in intrinsic defects, and an impurity band related mechanism of conduction. Films deposited under relatively high oxygen pressure were highly resistive and showed, upon ultraviolet light irradiation, grain boundary controlled electrical transport. An enhancement of the conductivity was observed when using a nitrogen atmosphere during the deposition, and oxygen atmosphere during cooling. In this case, the dependence of the conductivity with temperature followed Motts' Law of variable range hopping, characteristic of a material with localized states randomly located in space. Since the density of hopping centers appears to be much larger than the density of nitrogen incorporated in this sample, it is suggested that the nitrogen induces defects in the zinc oxide lattice that behave as localized hopping centers, as well as carrier suppliers, giving rise to the observed conductivity.

  14. Atmospheric dry deposition in the vicinity of the Salton Sea, California - I: Air pollution and deposition in a desert environment

    Science.gov (United States)

    Alonso, R.; Bytnerowicz, A.; Boarman, W.I.

    2005-01-01

    Air pollutant concentrations and atmospheric dry deposition were monitored seasonally at the Salton Sea, southern California. Measurements of ozone (O 3), nitric acid vapor (HNO3), ammonia (NH3), nitric oxide (NO), nitrogen dioxide (NO2) and sulfur dioxide (SO 2) were performed using passive samplers. Deposition rates of NO 3-, NH4+, Cl-, SO 42-, Na+, K+ and Ca2+ to creosote bush branches and nylon filters as surrogate surfaces were determined for one-week long exposure periods. Maximum O3 values were recorded in spring with 24-h average values of 108.8 ??g m-3. Concentrations of NO and NO2 were low and within ranges of the non-urban areas in California (0.4-5.6 and 3.3-16.2 ??g m-3 ranges, respectively). Concentrations of HNO3 (2.0-6.7 ??g m-3) and NH 3 (6.4-15.7 ??g m-3) were elevated and above the levels typical for remote locations in California. Deposition rates of Cl-, SO42-, Na+, K+ and Ca2+ were related to the influence of sea spray or to suspended soil particles, and no strong enrichments caused by ions originated by human activities were detected. Dry deposition rates of NO3- and NH4+ were similar to values registered in areas where symptoms of nitrogen saturation and changes in species composition have been described. Deposition of nitrogenous compounds might be contributing to eutrophication processes at the Salton Sea. ?? 2005 Elsevier Ltd. All rights reserved.

  15. Deposition from Ultra-Low Volume Application of Public Health Insecticides in a Hot Desert Environment.

    Science.gov (United States)

    Fisher, Michael L; Hoel, David F; Farooq, Muhammad; Walker, Todd W

    2015-06-01

    Three insecticides commonly used for mosquito and sand fly control were applied 30 min to 3 h after sunset during June and July 2010, at Camp Buehring, Kuwait, to determine the relative quantity of pesticides to height and distance traveled in a hot desert environment. A BVA dilution oil was used for the control. Oil-based adulticides were sprayed using a truck-mounted Curtis DynaFog Maxi-Pro 4 ultra-low volume (ULV) sprayer. Malathion (Fyfanon ULV, 96% active ingredient [AI]), resmethrin (Scourge 4+12, 4% AI), pyrethrins (ULD BP-300, 3% AI), and BVA Spray 13 (100% refined petroleum distillate) were mixed with Uvitex optical brightener fluorescent dye and applied at 2 speeds on evenings when wind speed was less than 16.1 km/h (10 mph). Collection targets using biodegradable cotton ribbons (1 m×2.5 cm) were later read with a fluorometer to quantify the amount of insecticide deposited on targets set at heights of 15.2, 76.2, and 152.4 cm (6, 30, and 60 in.) and distances of 1.5, 6.1, 15.2, 30.5, 61.0, and 91.4 m (5, 20, 50, 100, 200, and 300 ft). Mean insecticide deposition across all distances was 31% on 76.2-cm targets and 49% on 152.4-cm targets, while 15.2-cm targets typically collected insecticide deposition was 80% at or above 76.2 cm for all insecticides. This finding may explain in part why control of low-flying phlebotomine sand flies with ULV insecticides has been met with less than optimal success by US military forces deployed in the Middle East.

  16. A new approach to determine the phosphogypsum spread from the deposition site into the environment

    Energy Technology Data Exchange (ETDEWEB)

    Bituh, Tomislav, E-mail: tbituh@imi.hr [Institute for Medical Research and Occupational Health, Ksaverska cesta 2, HR-10000 Zagreb (Croatia); Vučić, Zlatko [Institute of Physics, Bijenička 46, HR-10000 Zagreb (Croatia); Marović, Gordana; Prlić, Ivica [Institute for Medical Research and Occupational Health, Ksaverska cesta 2, HR-10000 Zagreb (Croatia)

    2013-10-15

    Highlights: • Stationary diffusion model was used to describe phosphogypsum particle transfer. • Active electronic dosimeters ALARA were used to measure dose rates. • The mass concentration of particles was determined fiducially and realistically. • The model enabled to reduce the expenses and time of the measurements. -- Abstract: Phosphogypsum (PG), a waste product in phosphate fertilizer production, is characterized by technically enhanced natural radioactivity. The presented investigation was performed on a PG deposition site in Croatia. A new approach in the determination of the spread of PG particles from the deposition site into the environment based on the PG particle radioactivity measurements is suggested and explained. The stationary diffusion model was assumed and employed to describe long term PG particle transfer into the surroundings. The advantage of this method is that it requires a minimal number of measurement locations and offers a realistic and reliable distribution of PG particles. The mass concentration of PG particles decreased to the distance of about 3 m, at most up to 10 m from the deposition site edge. The results indicate that a unique mechanism of particle transport exists and the migration of PG particles by surface water is the dominant way of their spread. The particle current deduced from the measurements was very low, approximately 4.05 × 10{sup −2} kg/h, and the migration coefficient was approximately 1.69 × 10{sup −5} m{sup 2}/h. The obtained results confirmed the initial hypothesis of the stationarity of the migration process, reached within about 6 years.

  17. The influence of production conditions, starting material and deposition environment on charcoal alteration in a tropical biome.

    Science.gov (United States)

    Ascough, Philippa; Bird, Michael; Meredith, Will; Large, David; Snape, Colin; Manion, Corinne

    2014-05-01

    Natural and anthropogenic burning events are a key link in the global carbon cycle, substantially influencing atmospheric CO2 levels, and consuming c.8700 teragrams yr-1 of dry biomass [1,2,3]. An important result of this process is charcoal, when lignocellulosic structures in biomass (e.g. wood) are converted to aromatic domains with high chemical stability. Charcoal is therefore not readily re-oxidized to CO2, with estimates of 5-7 ky for the half-life of charcoal carbon in soils [3,4]. Charcoal's high carbon content coupled with high environmental resistance has led to the concept of biochar as a valuable means of global carbon sequestration, capable of carbon offsets comparable to annual anthropogenic fuel emissions [5,6,7]. Charcoal is not, however, an environmentally inert substance, and at least some components of charcoal are susceptible to alteration in depositional environments. Despite the importance of charcoal in global carbon cycling, the mechanisms by which charcoal is altered in the environment remain, as yet, poorly understood. This fact limits our ability to properly incorporate both natural environmental charcoal and biochar into global carbon budgets. This study aimed to improve understanding of charcoal alteration in the environment by examining the influence of production conditions, starting material and deposition environment on the physical and chemical characteristics of charcoal at a field site in the Daintree rainforest. These factors have been identified as critical in determining the dynamics of charcoal in depositional environments [8,9] and climatic conditions at the field site (in Tropical Queensland, Australia) are likely to result in extensive alteration of charcoal. Charcoal from wood (Nothofagus spp.), algae (Enteromorpha spp.), and sugarcane (Saccharum spp.) biomass was produced at temperatures over 300-500°C and exposed to conditions of varying pH and vegetation cover. The effect of these variables on charcoal chemistry

  18. Development of integrated protocols to track the deposition and impacts of metal contaminants in tidal riverine environments

    Science.gov (United States)

    Roe, Helen M.; Patterson, R. Timothy; Nasser, Nawaf; Edwards, Robin J.; Graham, Conor

    2016-04-01

    Tidally-influenced rivers are particularly vulnerable to the effects of metal contamination, yet are amongst the most complex fluvial environments in terms of their sediment deposition and transport patterns. We present the results of an interdisciplinary study that aims to elucidate the fluxes and deposition of metal contaminants in a tidally-influenced river system in Northern Ireland, with a view to developing protocols that will have wide applicability for the monitoring and assessment of metal contaminants in similar environments in other regions. We employ a novel methodology that combines ICPMS analysis of sediments, ITRAX-based core analysis and the examination a important group of shelled protozoans (foraminifera), which occur widely in tidal riverine environments, and which are highly sensitive to metal contamination. The responses shown by the group vary between species and with different levels of contaminant exposure. Some species, for example, show increased relative abundances in proximity to discharge sources, whilst others develop chamber deformities. Application of our integrated multiproxy approach to the analysis of surface sediment samples and cores provides a framework for assessing both the spatial and temporal patterns of metal deposition and the impact of contaminants on the biota. Modern sediment samples (n=90) were collected at varying distances from a point contamination source (a former industrial site) in different morpho-sedimentary settings. The impact of 25 measured variables on the modern foraminiferal faunas was considered, including 20 metals, pH, conductivity, elevation and particle size. Channel sediments in close proximity to the contamination source and with the highest levels of Fe, Cu, Zn, Mg and As, yielded the sparsest foraminiferal faunas (Shannon Diversity Index values 0-1.5), whilst the highest prevalence of foraminiferids showing chamber deformities were observed in channel edge and levée bank sites. Kernal density

  19. δ13C and δ15N of moss Haplocladium microphyllum (Hedw.) Broth. for indicating growing environment variation and canopy retention on atmospheric nitrogen deposition

    Science.gov (United States)

    Liu, Xue-Yan; Xiao, Hua-Yun; Liu, Cong-Qiang; Li, You-Yi

    Mosses have been recognized as a useful tool for biomonitoring atmospheric deposition and assessing regional environment. This study was carried on whether the same moss growing in areas with identical regional atmospheric deposition while under different growing environments would have the same indicating signals. Similar variations in mean δ13C and δ15N signatures were found between mosses collected from five habitats, with an increasing sequence from mosses under canopies to epilithic mosses, indicating that habitats were potentially regulating δ13C and δ15N values of mosses. Dryer habitats (lower water availability) and input of more aerosol N were the main reasons for higher δ13C and δ15N values of mosses at open sites (especially for epilithic species), while more negative values of mosses under canopies were attributed to their wetter habitats and less uptake of aerosol N. Additionally, δ15N values not δ13C varied linearly with canopy thickness from -7.84‰ (1 m) to -4.71±0.7‰ (4 m), suggesting δ15N was more sensitive for indicating canopy retention. Consequently, isotopic data of mosses under different environments could not be compared for atmospheric deposition research with each other even collected at the same site. Moss δ13C and δ15N were affected not only by regional atmospheric N sources but also by their growing environments. δ15N of epilithic Haplocladium microphyllum at open sites can be taken as confident bio-indicator of atmospheric N deposition, which would deepen the application of stable nitrogen isotope of bryophytes in atmosphere-plant system study.

  20. Depositional environment and provenance of Middle Siwalik sediments in Tista valley, Darjiling District, Eastern Himalaya, India

    Indian Academy of Sciences (India)

    Abhik Kundu; Abdul Matin; Malay Mukul

    2012-02-01

    The frontal part of the active, wedge-shaped Indo-Eurasian collision boundary is defined by the Himalayan fold-and-thrust belt whose foreland basin accumulated sediments that eventually became part of the thrust belt and is presently exposed as the sedimentary rocks of the Siwalik Group. The rocks of the Siwalik Group have been extensively studied in the western and Nepal Himalaya and have been divided into the Lower, Middle and Upper Subgroups. In the Darjiling–Sikkim Himalaya, the Upper Siwalik sequence is not exposed and the Middle Siwalik Subgroup exposed in the Tista river valley of Darjiling Himalaya preserves a ∼325 m thick sequence of sandstone, conglomerate and shale. The Middle Siwalik section has been repeated by a number of north dipping thrusts. The sedimentary facies and facies associations within the lithostratigraphic column of the Middle Siwalik rocks show temporal repetition of sedimentary facies associations suggesting oscillation between proximal-, mid- and distal fan setups within a palaeo-alluvial fan depositional environment similar to the depositional setup of the Siwalik sediments in other parts of the Himalaya. These oscillations are probably due to a combination of foreland-ward movement of Himalayan thrusts, climatic variations and mountain-ward shift of fanapex due to erosion. The Middle Siwalik sediments were derived from Higher- and Lesser Himalayan rocks. Mineral characteristics and modal analysis suggest that sedimentation occurred in humid climatic conditions similar to the moist humid climate of the present day Eastern Himalaya.

  1. Surface Structure of GaN(0001) in the Chemical Vapor Deposition Environment

    Energy Technology Data Exchange (ETDEWEB)

    Munkholm, A. [Chemistry Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Stephenson, G.B.; Eastman, J.A.; Thompson, C.; Auciello, O. [Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Thompson, C. [Department of Physics, Northern Illinois University, DeKalb, Illinois 60115 (United States); Fini, P.; Speck, J.S.; DenBaars, S.P. [Materials Department, University of California, Santa Barbara, California 93106 (United States); Fuoss, P.H. [ATT Laboratories---Research, Florham Park, New Jersey 07932 (United States)

    1999-07-01

    We report the first observation of the atomic-scale structure of the GaN(0001) surface in the metal-organic chemical vapor deposition environment. Measurements were performed using {ital in situ} grazing-incidence x-ray scattering. We determined the surface equilibrium phase diagram as a function of temperature and ammonia partial pressure, which contains two phases with 1{times}1 and ({radical} (3) {times}2{radical} (3) )R30{degree} symmetries. The ({radical} (3) {times}2{radical} (3) )R30{degree} phase is found to have a novel {open_quotes}missing row{close_quotes} structure with 1/3 of the surface Ga atoms absent. {copyright} {ital 1999} {ital The American Physical Society }

  2. Parametric optimization in virtual prototyping environment of the control device for a robotic system used in thin layers deposition

    Science.gov (United States)

    Enescu (Balaş, M. L.; Alexandru, C.

    2016-08-01

    The paper deals with the optimal design of the control system for a 6-DOF robot used in thin layers deposition. The optimization is based on parametric technique, by modelling the design objective as a numerical function, and then establishing the optimal values of the design variables so that to minimize the objective function. The robotic system is a mechatronic product, which integrates the mechanical device and the controlled operating device.The mechanical device of the robot was designed in the CAD (Computer Aided Design) software CATIA, the 3D-model being then transferred to the MBS (Multi-Body Systems) environment ADAMS/View. The control system was developed in the concurrent engineering concept, through the integration with the MBS mechanical model, by using the DFC (Design for Control) software solution EASY5. The necessary angular motions in the six joints of the robot, in order to obtain the imposed trajectory of the end-effector, have been established by performing the inverse kinematic analysis. The positioning error in each joint of the robot is used as design objective, the optimization goal being to minimize the root mean square during simulation, which is a measure of the magnitude of the positioning error varying quantity.

  3. Paleo-Environment and C-14 Dating: The Key to the Depositional Age of the Tha Chang and Related Sand Pits, Northeastern Thailand

    Science.gov (United States)

    Putthapiban, P.; Zolensky, M.; Jull, T.; Demartino, M.; Salyapongse, S.

    2012-01-01

    Tha Chang sand pits, Nakhon Ratchasima Province and many other sand pits in the area adjacent to the Mun River are characterized by their fluviatile environment in association with mass wasting deposits, along the paleo-river channel and the flood plain of the Mun River. Sediments of these deposits are characterized by clasts of various rock types especially the resistant ones with frequent big tree trunks, logs and wood fragments in different sizes and various stages of transformation from moldering stage to lignification and petrification. Widespread pyritization of the lower horizon suggests strongly reducing environment during burial. The Tha Chang deposits have been received much attention from geoscientists especially paleontologist communities, as they contain fragments of some distinct vertebrate species such as Stegadon sp., hominoid primate, rhinoceros Aceratherium and others. Based on the associated mammal fauna and hominoid fossils, the late Miocene ( 9 - 6 Ma) was given for the time of deposition of this sand and gravel unit. Some other reports believed that sediments and materials of these sand and gravel quarries (pits) were deposited by high-energy flood pulses contemporaneous with the tektites forming event during mid-Pleistocene at c. 0.8 Ma. Interpretation from Palynostratigraphical study suggested that the lower horizon of Tha Chang sand pit was deposited during Pliocene/Pleistocene period and the upper horizons are Pleistoncene/Holocene. It is crystal clear that all the fluviatile sediments including tektites and almost all fossil fragments being deposited in these sand pits were, likely a multiple times reworked materials. Only some old bamboo trees, some old crowling trees and fossils grasses observed on the old river bank are considered in situ. C-14 dating of 5 old wood specimens from Tha Chang Sand Pits, 15 old wood specimens from Chumpuang Sand Pits and one sample of old pottery from a Chumpuang Sand Pit were carried out in the NSF

  4. Understanding Cu release into environment from Kure massive sulfide ore deposits, Kastamonu, NW Turkey

    Science.gov (United States)

    Demirel, Cansu; Sonmez, Seref; Balci, Nurgul

    2014-05-01

    Covering a wide range on the earth's crust, oxidation of metal sulfide minerals have vital environmental impacts on the aquatic environment, causing one of the major environmental problems known as acid mine drainage (AMD). Located in the Kastamonu province of the Western Black Sea region, Kure district is one of the major copper mining sites in Turkey. Mining activities in the area heads back to ancient times, such that operation is thought to be started with the Roman Empire. Currently, only the underground mining tunnels of Bakibaba and Asikoy are being operated. Thus, mining heaps and ores of those pyritic deposits have been exposed to the oxidative conditions for so long. As a result of weathering processes of past and recent heaps of the Kure volcanic massive sulfide deposits in addition to the main ore mineral (chalcopyrite), significant amount of metals, especially Cu, are being released into the environment creating undesirable environmental conditions. In order to elucidate Cu release mechanisms from Kure pyritic ore deposits and mining wastes, field and laboratory approaches were used. Surface water and sediment samples from the streams around the mining and waste sites were collected. Groundwater samples from the active underground mining site were also collected. Physical parameters (pH, Eh, T°C, and EC) of water samples were determined in situ and in the laboratory using probes (WTW pH 3110, WTW Multi 9310 and CRISON CM 35). Metal and ion concentrations of the water samples were analysed using ICP-MS and DR 2800 spectrophotometer, respectively. High Cu, Co, Zn and Fe concentrations were determined in the water samples with pH values ranging from 2.9- 4. Cu concentrions ranges from 345 ppm to 36 ppm in the water samples. Consistent with the water samples, high Cu, Fe, Zn and Co were also determined in the sediment samples. Laboratory chalcopyrite oxidation experiments under the conditions representing the field site were set up as biological and

  5. Facies distribution, depositional environment, and petrophysical features of the Sharawra Formation, Old Qusaiba Village, Central Saudi Arabia

    Science.gov (United States)

    Abbas, Muhammad Asif; Kaminski, Michael; Umran Dogan, A.

    2016-04-01

    moderate-scale transgressive episodes, while the thin shale interbeds in the middle and upper part of the Sharawra Formation represent small-scale transgressions. Overall, the Sharawra Formation contains a series of repetitive transgressive and regressive events and has been interpreted as a pro-deltaic deposit in previous studies. In the present study, the lowermost sandstone thickly bedded facies lie within the transition zone environment. The siltstone facies and the horizontally stratified facies show a middle shore face environment. The middle shore face environment is present locally. The bioturbation in the uppermost facies is indicative of the upper shore face environment. The porosity values do not vary much, as the average porosity for the sandstone facies is about 15%, for the siltstones it ranges about 7%. The permeability is variable throughout the formation, the values range from 50 to 300 md. Although sandstone has a good porosity and permeability, the siltstone facies exhibit poor petrophysical characteristics. In terms of reservoir characterization, the mineralogical mature, moderately well sorted top most sandstone facies, with appreciable porosity and permeability can be considered as a potential reservoir rock. This study has provided a base for future quantitative studies in this important formation in the area.

  6. Sedimentary processes and depositional environments of the Horn River Shale in British Columbia, Canada

    Science.gov (United States)

    Yoon, Seok-Hoon; Koh, Chang-Seong; Joe, Young-Jin; Woo, Ju-Hwan; Lee, Hyun-Suk

    2017-04-01

    The Horn River Basin in the northeastern British Columbia, Canada, is one of the largest unconventional gas accumulations in North America. It consists mainly of Devonian shales (Horn River Formation) and is stratigraphically divided into three members, the Muskwa, Otterpark and Evie in descending order. This study focuses on sedimentary processes and depositional environments of the Horn River shale based on sedimentary facies analysis aided by well-log mineralogy (ECS) and total organic carbon (TOC) data. The shale formation consists dominantly of siliceous minerals (quartz, feldspar and mica) and subordinate clay mineral and carbonate materials, and TOC ranging from 1.0 to 7.6%. Based on sedimentary structures and micro texture, three sedimentary facies were classified: homogeneous mudstone (HM), indistinctly laminated mudstone (ILM), and planar laminated mudstone (PLM). Integrated interpretation of the sedimentary facies, lithology and TOC suggests that depositional environment of the Horn River shale was an anoxic quiescent basin plain and base-of-slope off carbonate platform or reef. In this deeper marine setting, organic-rich facies HM and ILM, dominant in the Muskwa (the upper part of the Horn River Formation) and Evie (the lower part of the Horn River Formation) members, may have been emplaced by pelagic to hemipelagic sedimentation on the anoxic sea floor with infrequent effects of low-density gravity flows (turbidity currents or nepheloid flows). In the other hand, facies PLM typifying the Otterpark Member (the middle part of the Horn River Formation) suggests more frequent inflow of bottom-hugging turbidity currents punctuating the hemipelagic settling of the background sedimentation process. The stratigraphic change of sedimentary facies and TOC content in the Horn River Formation is most appropriately interpreted to have been caused by the relative sea-level change, that is, lower TOC and frequent signal of turbidity current during the sea

  7. Depositional environment and origin of the Lilaozhuang Neoarchean BIF-hosted iron-magnesite deposit on the southern margin of the North China Craton

    Science.gov (United States)

    Huang, Hua; Zhang, LianChang; Fabre, Sébastien; Wang, ChangLe; Zhai, MingGuo

    2017-07-01

    The Neoarchean Lilaozhuang iron-magnesite deposit is located in the middle of the Huoqiu banded iron formation (BIF) ore belt in Anhui Province on the southern margin of the North China Craton. The Huoqiu BIF is the unique one that simultaneously develops quartz-type, silicate-type, and carbonate-type magnetite in the region. The Lilaozhuang deposit is characterized by magnesium-rich carbonate (magnesite) in magnetite ores. The BIF-hosted iron ores include mainly of silicate type and carbonate type, with a small amount of quartz type, which chiefly exhibit banded and massive structure, with minor disseminated structure. The magnesite ores occur as crystal-like bright white and exhibits massive structure. The Y/Ho ratio and REY pattern of both iron and magnesite ores are similar to that of seawater, while Eu shows positive anomaly, which is the sign of seafloor hydrothermal mixture. These features suggest that ore-forming materials of iron and magnesium in the Lilaozhuang deposit are mainly from the mixture of seafloor hydrothermal and seawater. Both ores do not exhibit negative Ce anomaly, which indicates that the deposit was formed in an environment showing a lack of oxygen. C-O isotopic compositions indicate that magnesite ore has been reformed by metamorphism of low amphibolite facies and later hydrothermal alteration. Based on the comprehensive analysis, authors suggest that iron and magnesite ores in the Lilaozhuang deposits formed in a confined sea basin on continental margin and was influenced by later complex geological processes.

  8. Depositional Environments of Late Danian Plant Localities: Chubut Provice, Patagonia, Argentina

    Science.gov (United States)

    Comer, E.; Slingerland, R. L.; Wilf, P.

    2010-12-01

    Diverse, well-preserved macroflora are observed within Cretaceous and Paleocene sediments of Chubut Province, Patagonia, Argentina. These macroflora are the most well preserved early Paleocene flora from Gondwana and add new insight into the diversity and environments of that epoch. Two major sites of fossil preservation, Palacio de los Loros and Parque Provincial Ormachea, sit near the top of the Late Danian (65.5-61.7 Ma) Salamanca Formation. Understanding the depositional history of the Salamanca is important in characterizing paleoenvironments in which these flora lived and relating these Patagonian macroflora to concurrent Paleocene flora within the Gondwanan supercontinent. During a two week field season, twenty stratigraphic sections were measured along the outcrop belt at Palacio de los Loros and Ormachea Park as well as two minor sites; Las Flores, and Rancho Grande. Photo mosaics, laser ranger data, and stratigraphic columns were merged with elevated geologic maps and imported into Fledermaus to generate a 3-D visualization of facies relationships. Rock samples were also collected and will be thin sectioned and analyzed for petrography and grain size. The Salamanca Fm. consists of 7 facies, listed here in stratigraphically ascending order: 1)Transgressive sands, 2)Wispy-bedded claystone, 3)Banco Verde, 4)White Cross bedded sandstone, 5)Accretion set siltstone, 6)Transitional silty claystone and 7)Banco Negro. Based on these facies, the Salamanca Fm. is interpreted as a marine-shelf to brackish, tide-dominated, estuarine deposit. The base of the Salamanca Fm. rests on an unconformity representing a marine flooding surface and lower sections of the Salamanca, facies 1 and 2, contain abundant glauconite and fossils indicative of a marine shelf environment. These facies give way upwards to bi-directional trough cross bedded sandstones interspersed with flaser bedded sandy siltstones (facies 3 and 4) indicating a less marine estuary with strong flow regimes

  9. The Shublik Formation and adjacent strata in northeastern Alaska description, minor elements, depositional environments and diagenesis

    Science.gov (United States)

    Tourtelot, Harry Allison; Tailleur, Irvin L.

    1971-01-01

    occurrence of silver and 300 ppm lead in gouge along a shear plane may be the result of metals introduced from an extraneous source. The deposits reflect a marine environment that deepened somewhat following deposition of the Sadlerochit Formation and then shoaled during deposition of the upper limestone-siltstone unit. This apparently resulted from a moderate transgression and regression of the sea with respect to a northwest-trending line between Barrow and the Brooks Range at the International Boundary. Nearer shore facies appear eastward. The phosphate in nodules, fossil molds and oolites, appears to have formed diagenetically within the uncompacted sediment.

  10. Effects of ground freezing and snow avalanche deposits on debris flows in alpine environments

    Directory of Open Access Journals (Sweden)

    E. Bardou

    2004-01-01

    Full Text Available Debris flows consist of a mixture of water and sediments of various sizes. Apart from few exceptions, the water is usually contributed directly from precipitation. In a high mountain environment like the Alps, it appears necessary to consider infiltration of water into the ground during rainfall events, the runoff characteristics and the potential supply of sediment as a function of a multitude of climatic and hydrogeological factors. This paper outlines several new processes - either linked to ice formation in the ground before an event, or to the presence of snow avalanche deposits - that change the probability of observing an event. These processes were identified during field observations connected with extreme weather events that occurred recently in the Valais Alps (south-western Switzerland: they can be seen as factors either amplifying or reducing the potential of slope instability caused by the precipitation event. An intense freezing of the ground during the week preceding the exceptional rainfall event in mid-October 2000 amplified the probability of triggering debris flows between roughly 1800 and 2300m asl. Both growth of ice needles and superficial ground freezing destroyed soil aggregates (increasing the availability of sediments and/or, a deeper ground freezing resulted in decreased infiltration rate (increased runoff during the first hours of heavy rainfall. The presence of snow avalanche deposits in a gully could be simultaneously an amplifying factor (the snow deposits increase the base flow and create a sliding plane for the sediments, mainly at the time of summer storms or a reducing factor (reduction in the impact energy of the raindrops, mainly at the time of winter storms of the risk of triggering debris flows. If it is not currently possible to establish rainfall threshold values for debris flow triggering, the knowledge and the implementation of these processes in the analysis of the potential triggering (for example by

  11. Linking microbial ultrastructure and physiology to iron depositional processes in deep sea hydrothermal environments

    Science.gov (United States)

    Chan, C. S.; Fleming, E. J.; Emerson, D.; Edwards, K. J.

    2008-12-01

    Clara S. Chan, Emily Fleming, David Emerson, Katrina J. Edwards Iron microbial mats have been discovered in a variety of deep-sea hydrothermal environments and are increasingly being recognized as more seafloor is explored. The predominant structures found in many of these mats are iron oxyhydroxide-rich filaments. One of the most common structures is a helical stalk bearing a resemblance to the twisted stalk of the terrestrial iron-oxidizing microbe, Gallionella ferruginea. While Gallionella has not been detected in, or isolated from, these mats microaerophilic iron-oxidizing, a stalk- forming bacterium, Mariprofundus ferrooxydans (PV-1 and related strains) has been isolated from mats at the Loihi seamount in Hawaii (Emerson et al. 2007, PLoS One 2(8): e667). Fossilized aggregates of iron filaments have been observed in the rock record (e.g. Little et al. 2004, Geomicrobiol. J. 21:415), and may represent ancient versions of these microbial mats. If this is shown to be true, such filaments would represent one of the few microfossil morphologies that can be linked to a specific microbial metabolism. We have used a combination of test tube culturing, microslide culturing, time lapse microscopy, and electron microscopy to study Mariprofundus stalk morphology and genesis and link these details to physiological responses to environmental chemistry. The goals include determining specific attributes of stalk morphology that can be used to determine the biogenicity of putative iron microfossils, and interpret the conditions of the depositional environment. Light microscopic observation of microslide cultures over the course of several days allowed for determination of bacterial response to developing oxygen and Fe(II) gradients. Once gradients have been established, given an abundant supply of oxygen, cells congregate in a band perpendicular to the gradient and stalks are formed, growing in the direction of increasing oxygen (and decreasing Fe) concentration. This

  12. Post-depositional alteration of benthic foraminifera in a methane seep environment

    Science.gov (United States)

    Schneider, Andrea; Cremiere, Antoine; Panieri, Giuliana; Lepland, Aivo; Knies, Jochen

    2016-04-01

    Benthic foraminifera tests from the sediment cores taken from the Vestnesa Ridge, one of the northernmost known marine methane hydrate reservoir, were studied for their visual appearance, mineral and stable carbon isotopic composition in order to explore their indicator potential in a methane seep environment. The Vestnesa Ridge is a sediment drift located in 1200m water depth at 79°N at Svalbard's northwestern continental margin. Observations of gas flares originating from pockmarks that are aligned along the crest of the ridge show ongoing methane emission. A distinct sediment layer containing a fossilized assemblage of chemosynthetic bivalves indicates methane seepage activity at least in the late Pleistocene. We have examined the state of preservation and geochemical characteristics of foraminifera tests from this bivalve shell horizon. Tests of the benthic foraminifera species Cassidulina neoteretis display a variable degree of post-depositional alteration and formation of diagenetic carbonate overgrowths on calcitic primary tests. Using binoculars, scanning electron microscope imagery and energy dispersive x-ray spectroscopy, we distinguish visually and mineralogically different diagenetic phases on the external and internal test surfaces. Pristine and smooth test surfaces act as nucleation templates for precipitation of authigenic Mg-calcite crystals causing complete filling of chambers and encrustation of the external test surfaces. The presence of Mg-calcite indicates the overgrowth is precipitating in sulfate-poor sediments. In addition to benthic foraminifera, we have studied the mineralogical and stable carbon and oxygen isotope composition of authigenic carbonate nodules found in the bivalve shell horizon. The mineralogical nature of the carbonates and overgrowths on the foraminifera tests were found to be identical. The δ13C value of the carbonate nodules is as low as -32.3‰ indicating their methane-derived origin. Authigenic carbonate coated

  13. The Influence of Individual Characteristics and the Work Environment on Varying Levels of Training Outcomes. [and] Invited Reaction.

    Science.gov (United States)

    Tracey, J. Bruce; Hinkin, Timothy R.; Tannenbaum, Scott; Mathieu, John E.; Black, William C.

    2001-01-01

    A study by Tracey, Hinkin, Tannenbaum, and Mathieu of 115 management trainees and 305 supervisors/coworkers found that job involvement, commitment, and work environment influenced pretraining self-efficacy and motivation. Hierarchical relationships between levels of training effectiveness criteria were identified. Black's response cites their…

  14. Deposition rates of fungal spores in indoor environments, factors effecting them and comparison with non-biological aerosols

    Science.gov (United States)

    Kanaani, Hussein; Hargreaves, Megan; Ristovski, Zoran; Morawska, Lidia

    Particle deposition indoors is one of the most important factors that determine the effect of particle exposure on human health. While many studies have investigated the particle deposition of non-biological aerosols, few have investigated biological aerosols and even fewer have studied fungal spore deposition indoors. The purpose of this study was, for the first time, to investigate the deposition rates of fungal particles in a chamber of 20.4 m 3 simulating indoor environments by: (1) releasing fungal particles into the chamber, in sufficient concentrations so the particle deposition rates can be statistically analysed; (2) comparing the obtained deposition rates with non-bioaerosol particles of similar sizes, investigated under the same conditions; and (3) investigating the effects of ventilation on the particle deposition rates. The study was conducted for a wide size range of particle sizes (0.54-6.24 μm), at three different air exchange rates (0.009, 1.75 and 2.5 h -1). An Ultraviolet Aerodynamic Particle Sizer Spectrometer (UVAPS) was used to monitor the particle concentration decay rate. The study showed that the deposition rates of fungal spores ( Aspergillus niger and Penicillium species) and the other aerosols (canola oil and talcum powder) were similar, especially at very low air exchange rates (in the order of 0.009). Both the aerosol and the bioaerosol deposition rates were found to be a function of particle size. The results also showed increasing deposition rates with increasing ventilation rates, for all particles under investigation. These conclusions are important in understanding the dynamics of fungal spores in the air.

  15. Effects of Super Strom Sandy on Depositional Environments Offshore Long Island, New York

    Science.gov (United States)

    Hosseini, P.; McHugh, C. M.; Christensen, B. A.; Dutton, J.; Brownawell, B.; Gurung, D.

    2013-12-01

    Hurricane Sandy's landfall affected the coastlines over a broad swath of mid-Atlantic including New York, New Jersey, Delaware, Maryland, Virginia, and North Carolina. The effects included breaching, overwash and erosion of barrier islands, some of which are heavily populated and sustained extensive damage. The peak storm-tide elevation produced by Hurricane Sandy measured by USGS stations in Jamaica Bay was about 3.5 m, 1.4 m more than the historical peak-water level elevations in the same area. As part of a National Science Foundation RAPID response we sampled the sediment in West Bay, Middle Bay, East Bay, Jones Inlet and Reynolds Channel of Long Island, New York from the R/V Pritchard. The sediment sampling took place 4 months after the storm and prior to any similar large storms. The sampling strategy was designed to characterize the post-storm sedimentation in distinct depositional environments. In this survey 156 grab samples were recovered from areas, many of which had been sampled prior to the storm. The samples were analyzed for grain size variability, short-lived radioisotopes and x-ray fluorescence elemental analyses. Google Earth images from before and after the storm reveal moderate to severe erosion and overwash of the dunes in Jones inlet, and Middle and East Bays. The Long Beach barrier island tidal marshes were submerged for several days post Sandy and underwent severe erosion. The storm surge brought from offshore a layer of coarse sand that was deposited over mussel beds. Most of the mussels were dead indicative of the strength of the waves. Be-7 concentrations allowed tracking the path of the storm from the bays and inlets, to the offshore. Some of the highest Be-7 concentrations ever detected in the local estuaries: 5,329, 4,955 and 4,553 pCi/kg were measured in West Bay and Middle Bay Channels. Additionally, unusually high Be-7 concentrations of 2,130 pCi/kg were recorded ~5.24 km offshore from Long Beach barrier island four months after the

  16. Hot-wire substoichiometric tungsten oxide films deposited in hydrogen environment with n-type conductivity

    Science.gov (United States)

    Kostis, I.; Michalas, L.; Vasilopoulou, M.; Konofaos, N.; Papaioannou, G.; Iliadis, A. A.; Kennou, S.; Giannakopoulos, K.; Papadimitropoulos, G.; Davazoglou, D.

    2012-11-01

    Substoichiometric tungsten oxide nanostructured films were synthesized by a hot-wire deposition technique in hydrogen-rich environment and characterized for their structural and electrical properties. A semiconducting behaviour was identified, allowing n-type conductivity even at room temperature which is an important result since it is well known that fully stoichiometric tungsten trioxide is nearly an insulator. Current-voltage characteristics for various temperatures were measured for tungsten oxide/Si heterostructures and analysed using proper modelling. As a result, the conduction mechanism inside the films was identified and found to be of a dual nature, with variable range hopping being dominant at near room temperatures. The saturation current was found to be thermally activated and the activation energy was calculated at 0.40 eV and the grain boundaries barrier at 150 meV. From Hall measurements it was also revealed that the dominant carriers are electrons and a carrier concentration of about 1014 cm-3 was estimated.

  17. Characterization of organic matter deposited in the oriental zone from Moknine hypersaline environment, oriental Tunisia

    Institute of Scientific and Technical Information of China (English)

    Raja CHAIRI; Zohra EL ASMI DJELLOULI

    2005-01-01

    The geochemistry data show that the total organic carbon (TOC) contents are high in the surface sediments in the eastern part of the Moknine's Sebkha. Low decreasing of organic matter (OM) with increasing depth indicates the good preservation of OM in modern sediments. "Lignite levels" inserted in the sand sequence and deposited at the edge and in the intermediate zone are considered as lithologic and organic markers. It is characterized by high TOC and poor hydrogen index (HI), indicating a higher plant origin and good preservation of OM in thin beds under anoxic condition.In all samples low values of HI are typical for strong terrigenous input in the Sebkha. Gas chromatography (GC) of saturate fraction showed that OM in the border zone is provided from plants but in the central zone OM is a mixture of terrestrial fraction and little fraction from microalgae. The study of free lipids indicated that this environment was influenced by intense bacterial and microbial activities, as evidenced by the abundance of n-alkanes and nC 18-nC 22.

  18. The Neogene molasse deposits of the Zagros Mountains in central Dezful Embayment: facies, sedimentary environments and controls

    Directory of Open Access Journals (Sweden)

    Ali Hossein Jalilian

    2016-03-01

    Full Text Available The upper part of Neogene sequence of the Zagros Mountains consists of a clastic succession which is identified as Aghajari and Bakhtyari formations. The sequence is an excellent example of synorogenic sedimentation or molasse deposited in northern portion of the Zagros foreland basin. Sedimentological analysis of an outcrop section representing Miocene-Pliocene sediments in central Dezful Embayment resulted in recognizing 9 lithofacies and 4 architectural elements. These lithofacies include conglometate (Gt, Gh, Gmm, sandstone (Sp, Sh, Sr, St and mudstone (Fm, Fl that were deposited in meandering stream, braided river and alluvial fan environments. Paleocurrent analysis of cross-beds, channels and asymmetric ripple marks indicate that these Neogene clastics were mainly drived from Cretaceous to Paleogene highlands in the Zagros Mountains on the north. This stratigraphic record is coarsening-upward and formed by a regressive depositional megacycle under arid climate. Facies and depositional history analysis show that sedimentation of the Zagros molasse was primarily controlled by base-level changes rather than catchment lithology or climate. The sedimentary record of this regressive megacycle reveales the base-level was constantly falling down on one hand and the provenance was uplifting on the other hand. Tectonic activities and Zagros Mountains rising in the Late Miocene resulted in deposition of fining-upward point-bar and floodplain sequences of the Aghajari Formation in low-gradient meandering streams. The Lahbari Member of the Aghajari Formation represents deposition in braided rivers that composed predominantly of flood-plain deposits in the Early Pliocene. Finally, the sedimentary cycle of the Zagros molasse deposits terminated with massive conglomerates of the Bakhtyari Formation deposited in large alluvial fans near the source area.

  19. Characterization of photocatalytic TiO2 powder under varied environments using near ambient pressure X-ray photoelectron spectroscopy

    Science.gov (United States)

    Krishnan, Padmaja; Liu, Minghui; Itty, Pierre A.; Liu, Zhi; Rheinheimer, Vanessa; Zhang, Min-Hong; Monteiro, Paulo J. M.; Yu, Liya E.

    2017-01-01

    Consecutive eight study phases under the successive presence and absence of UV irradiation, water vapor, and oxygen were conducted to characterize surface changes in the photocatalytic TiO2 powder using near-ambient-pressure X-ray photoelectron spectroscopy (XPS). Both Ti 2p and O 1s spectra show hysteresis through the experimental course. Under all the study environments, the bridging hydroxyl (OHbr) and terminal hydroxyl (OHt) are identified at 1.1–1.3 eV and 2.1–2.3 eV above lattice oxygen, respectively. This enables novel and complementary approach to characterize reactivity of TiO2 powder. The dynamic behavior of surface-bound water molecules under each study environment is identified, while maintaining a constant distance of 1.3 eV from the position of water vapor. In the dark, the continual supply of both water vapor and oxygen is the key factor retaining the activated state of the TiO2 powder for a time period. Two new surface peaks at 1.7–1.8 and 4.0–4.2 eV above lattice oxygen are designated as peroxides (OOH/H2O2) and H2O2 dissolved in water, respectively. The persistent peroxides on the powder further explain previously observed prolonged oxidation capability of TiO2 powder without light irradiation. PMID:28240300

  20. Characterization of photocatalytic TiO2 powder under varied environments using near ambient pressure X-ray photoelectron spectroscopy

    Science.gov (United States)

    Krishnan, Padmaja; Liu, Minghui; Itty, Pierre A.; Liu, Zhi; Rheinheimer, Vanessa; Zhang, Min-Hong; Monteiro, Paulo J. M.; Yu, Liya E.

    2017-02-01

    Consecutive eight study phases under the successive presence and absence of UV irradiation, water vapor, and oxygen were conducted to characterize surface changes in the photocatalytic TiO2 powder using near-ambient-pressure X-ray photoelectron spectroscopy (XPS). Both Ti 2p and O 1s spectra show hysteresis through the experimental course. Under all the study environments, the bridging hydroxyl (OHbr) and terminal hydroxyl (OHt) are identified at 1.1–1.3 eV and 2.1–2.3 eV above lattice oxygen, respectively. This enables novel and complementary approach to characterize reactivity of TiO2 powder. The dynamic behavior of surface-bound water molecules under each study environment is identified, while maintaining a constant distance of 1.3 eV from the position of water vapor. In the dark, the continual supply of both water vapor and oxygen is the key factor retaining the activated state of the TiO2 powder for a time period. Two new surface peaks at 1.7–1.8 and 4.0–4.2 eV above lattice oxygen are designated as peroxides (OOH/H2O2) and H2O2 dissolved in water, respectively. The persistent peroxides on the powder further explain previously observed prolonged oxidation capability of TiO2 powder without light irradiation.

  1. Does the Effect of Person-Environment Fit on Work Attitudes Vary with Generations? Insights from the Tourism Industry

    Directory of Open Access Journals (Sweden)

    Bednarska Marlena A.

    2017-03-01

    Full Text Available There is an intrinsic link between the success of service firms and the availability of high-quality human resources, making employee attitudes and behaviors a critical concern for service organizations. This paper examines the role of generational differences in the relationship between person-environment fit, job satisfaction and work engagement in the tourism industry. The study was based on a group of 981 tourism employees in 15 localities in Poland. Data were collected through self-administered paper-based questionnaires. The hypothesized relationships were tested using a hierarchical regression analysis. This research revealed that Generation Y employees experienced lower job satisfaction, lower work engagement, and a lower degree of needs being met in the workplace than did their predecessors. It was also found that person-group fit was a stronger predictor of work attitudes for Millennials. The paper contributes to the ongoing debate on generational diversity in the workplace and its implication for human resources management. Specifically, in the service context, it adds a generational perspective of the person-environment fit influence on work-related attitudes.

  2. North Atlantic Ocean deep-water processes and depositional environments: A study of the Cenozoic Norway Basin

    Science.gov (United States)

    Oline Hjelstuen, Berit; Andreassen, Elin V.

    2015-04-01

    Despite the enormous areas deep-water basins occupy in modern oceans, our knowledge about them remains poor. At depths of greater than 2000 m, the Cenozoic Norway Basin in the northernmost part of the Atlantic Ocean, is one such basin. Interpretation of 2D multichannel seismic data suggests a three-stage evolution for the Norway Basin. (1) Eocene-Pliocene. This time period is characterised by deposition of ooze-rich sediments in a widening and deepening basin. (2) Early-Middle Pleistocene. A significant shift in sedimentary processes and depositional environments took place in the Early Pleistocene. Mass failures initiated on the Norwegian continental slope, and three Early and Middle Pleistocene slide debrites, with maximum thicknesses of 600 m and sediment volumes of up to 25000 km3, were deposited. With ages estimated at c. 2.7-1.7 Ma, 1.7-1.1 Ma and 0.5 Ma, these slide deposits are among the largest identified worldwide, and among the oldest mapped along the entire NE Atlantic continental margin. (3) Late Pleistocene-Present. Since c. 0.5 Ma the Norway Basin has been effected by glacigenic debris flows, the Storegga Slide and hemipelagic-glacimarine sedimentation. These sedimentary processes were active during a time of repeated shelf-edge ice advances along the NE Atlantic continental margin. This study shows that deep-water basins represent dynamic depositional environments reflecting regional tectonic and climatic changes trough time.

  3. Forms of uranium associated to silica in the environment of the Nopal deposit (Mexico)

    Science.gov (United States)

    Allard, T.; Othmane, G.; Menguy, N.; Vercouter, T.; Morin, G.; Calas, G.; Fayek, M.

    2011-12-01

    The understanding of the processes that control the transfers of uranium in the environment is necessary for the safety assessement of nuclear waste repositories. In particular, several poorly ordered phases (e.g. Fe oxihydroxides) are expected to play an important role in trapping uranium from surface waters. Among them, natural systems containing amorphous silica are poorly documented. A former study from the environment of the Peny mine (France) showed the importance of silica in uranium speciation [1]. The Nopal uranium deposit is located in volcanic tuff from tertiary period. It hosted several hydrothermal alteration episodes responsible for clay minerals formation. A primary uranium mineralisation occurred in a breccia pipe, consisting in uraninite, subsequently altered in secondary uranium minerals among which several silicates. Eventually, opal was formed and coated uranyl silicates such as uranophane and weeksite [2], [3]. Opals also contain minor amounts of uranium. The Nopal deposit is still considered as a natural analogue of high level nuclear waste repository located in volcanic tuff. It may be used to reveal the low temperature conditions of trapping of uranium in systems devoid of iron oxides such as silica-containing ones. The aim of this study is then to determine the uranium speciation, and its possible complexity, associated to these opals that represent a late trapping episode. It will provide insights ranging from the micrometer scale of electron microscopies to the molecular scale provided by fluorescence spectroscopy. Three samples of green or yellow opals have been analysed by a combination of complementary tools including scanning electron microscopy (SEM) on cross-sections, transmission electron microscopy (TEM) on focused ion beam (FIB) films, cathodoluminescence and time-resolved laser fluorescence spectroscopy (TRLFS). Uranium speciation was found to be complex. We first evidence U-bearing microparticles of beta-uranophane Ca[(UO2)(Si

  4. Precise Nanoscale Surface Modification and Coating of Macroscale Objects: Open-Environment in Loco Atomic Layer Deposition on an Automobile.

    Science.gov (United States)

    Mousa, Moataz Bellah M; Oldham, Christopher J; Parsons, Gregory N

    2015-09-09

    The fundamental chemical reaction conditions that define atomic layer deposition (ALD) can be achieved in an open environment on a macroscale surface too large and complex for typical laboratory reactor-based ALD. We describe the concept of in loco ALD using conventional modulated reactant flow through a surface-mounted "ALD delivery head" to form a precise nanoscale Al2O3 film on the window of a parked automobile. Analysis confirms that the processes eliminated ambient water contamination and met other conditions that define ALD growth. Using this tool, we demonstrate open-ambient patterned deposition, metal corrosion protection, and polymer surface modification.

  5. The East Africa Oligocene intertrappean beds: Regional distribution, depositional environments and Afro/Arabian mammal dispersals

    Science.gov (United States)

    Abbate, Ernesto; Bruni, Piero; Ferretti, Marco Peter; Delmer, Cyrille; Laurenzi, Marinella Ada; Hagos, Miruts; Bedri, Omar; Rook, Lorenzo; Sagri, Mario; Libsekal, Yosief

    2014-11-01

    inspection of the Agere Selam (Mekele) intertrappean beds revealed the occurrence of lacustrine limestones and diatomites, which were contrastingly quite subordinate with respect to the fine clastic sediments found in the nearby Amba Alaji area. Further south, the intertrappean section in the Jema valley (100 km north of Addis Ababa and close to the Blue Nile gorge) is 120 m thick with predominant clastic sediments and a few diatomites at the top. Literature information from 35 additional sites, including northern Kenya, Yemen, Sudan and Saudi Arabia sections, confirms the fluvial and lacustrine depositional environment of the intertrappean beds, underlines the interest in their mammal fauna (Chilga, Losodok), and reports exploitable coal seams for some of them. As for the vegetal landscape in which the intertrappean beds were deposited, pollen and plant analysis results indicative of a tropical wet forest, similar to that of present-day western Africa. Another common feature of the intertrappean beds is their relatively limited thickness, averaging a few tens of meters, but reaching a few hundred meters in graben-related basins, such as Delbi Moye in southern Ethiopia. In most cases only thin, lens-shaped successions were deposited above the hummocky topography of their volcanic substratum, commonly unaffected by significant faulting. An average duration of the intertrappean beds is from one to three million years. This time interval is commonly matched by a few tens (or more rarely, hundreds) of meters of sediments left over after erosive episodes or depositional starvation. As to the lateral continuity of the intertrappean beds, the present-day outcrops show large differences: from some tens of kilometers in the Mendefera area, to a few tens of kilometres in the Jema valley, and to a few hundreds meters in the Agere Selam (Mekele) area. Even if it is difficult to quantify the original size of the sedimentation areas, it nevertheless proves that the intertrappean basins

  6. Stratigraphy and depositional environments of the upper Pleistocene Chemehuevi Formation along the lower Colorado River

    Science.gov (United States)

    Malmon, Daniel V.; Howard, Keith A.; House, P. Kyle; Lundstrom, Scott C.; Pearthree, Philip A.; Sarna-Wojcicki, Andrei M.; Wan, Elmira; Wahl, David B.

    2011-01-01

    The Chemehuevi Formation forms a conspicuous, widespread, and correlative set of nonmarine sediments lining the valleys of the Colorado River and several of its larger tributaries in the Basin and Range geologic province. These sediments have been examined by geologists since J. S. Newberry visited the region in 1857 and are widely cited in the geologic literature; however their origin remains unresolved and their stratigraphic context has been confused by inconsistent nomenclature and by conflicting interpretations of their origin. This is one of the most prominent stratigraphic units along the river below the Grand Canyon, and the formation records an important event or set of events in the history of the Colorado River. Here we summarize what is known about these deposits throughout their range, present new stratigraphic, sedimentologic, topographic, and tephrochronologic data, and formally define them as a lithostratigraphic unit. The Chemehuevi Formation consists primarily of a bluff-forming mud facies, consisting of gypsum-bearing, horizontally bedded sand, silt, and clay, and a slope-forming sand facies containing poorly bedded, well sorted, quartz rich sand and scattered gravel. The sedimentary characteristics and fossil assemblages of the two facies types suggest that they were deposited in flood plain and channel environments, respectively. In addition to these two primary facies, we identify three other mappable facies in the formation: a thick-bedded rhythmite facies, now drowned by Lake Mead; a valley-margin facies containing abundant locally derived sediment; and several tributary facies consisting of mixed fluvial and lacustrine deposits in the lower parts of major tributary valleys. Observations from the subsurface and at outcrops near the elevation of the modern flood plain suggest that the formation also contains a regional basal gravel member. Surveys of numerous outcrops using high-precision GPS demonstrate that although the sand facies commonly

  7. Depositional Environment of Fine-Grained Sedimentary Rocks of the Sinamar Formation, Muara Bungo, Jambi

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    M. Heri Hermiyanto Zajuli

    2014-07-01

    Full Text Available DOI: 10.17014/ijog.v8i1.153The research area is situated in the northwestern side of South Sumatra Basin, which is a part of Muara Bungo Regency, Jambi Province. The Oligocene Sinamar Formation consists of shale, claystone, mudstone, sandstone, conglomeratic sandstone, and coal-seam intercalations. This research was focused on fine sedimentary rock of Sinamar Formation, such as shale, claystone, and mudstone. Primary data were collected from SNM boreholes which have depths varying from 75 m up to 200 m, and outcrops that were analyzed by organic petrographic method, gas chromatography-mass spectrometry (GC-MS of normal alkanes including isoprenoids, and sterane. The dominant maceral group is exinite, composed of alginite (3.4 - 18%, and resinite (1.6 - 5.6%, while vitrinite maceral consists of tellocolinite 0.4 - 0.6%, desmocollinite 0.4%, and vitrodetrinite 8.4 - 16.6%. Organic petrography and biomarker analyses show that organic materials of shales were derived from high plants and algae especially Botrycoccus species. Botrycoccus and fresh water fish fossil, found in the shale indicate a lacustrine environment.

  8. EXAFS study on yttrium oxide thin films deposited by RF plasma enhanced MOCVD under the influence of varying RF self-bias

    Energy Technology Data Exchange (ETDEWEB)

    Chopade, S.S. [Laser and Plasma Technology Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Nayak, C.; Bhattacharyya, D.; Jha, S.N.; Tokas, R.B.; Sahoo, N.K. [Atomic and Molecular Physics Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Patil, D.S., E-mail: dspatil@barc.gov.in [Laser and Plasma Technology Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India)

    2014-09-30

    Highlights: • Local structure and surface morphology of Y{sub 2}O{sub 3} thin films deposited by RF plasma MOCVD at different RF self-bias level investigated by EXAFS and AFM. • Bond length and oxygen coordination changes with bias. • Films are nanostructured with structural distortion at higher bias. • Surface morphology of films changes with bias. • Changes observed in local structural parameters are correlated with observed properties of films. • EXAFS study on Y{sub 2}O{sub 3} films deposited under different RF self-bias levels is not been reported so far. - Abstract: Extended X-ray absorption fine structure (EXAFS) and atomic force microscopy (AFM) studies are carried out on yttrium oxide (Y{sub 2}O{sub 3}) thin films deposited by radio frequency plasma assisted metalorganic chemical vapor deposition (MOCVD) process at different RF self-bias (−50 V to −175 V with a step of −25 V) on silicon substrates. A (2,2,6,6-tetramethyl-3,5-heptanedionate) yttrium (commonly known as Y(thd){sub 3}) precursor is used in a plasma of argon and oxygen gases at a substrate temperature of 350 °C for deposition. To gain profound understanding about influence of RF self-bias on the properties of the deposited Y{sub 2}O{sub 3} thin films, the films are characterized by EXAFS and AFM measurements. From the EXAFS measurements it is observed that oxygen co-ordination is high for the film deposited at the lowest self bias (−50 V) which is due to presence of higher amount of hydroxyl group in the sample. Oxygen coordination however decrease to lower values for the films deposited at self bias of −75 V. Y-O bond length decreases gradually with increase in self bias indicating reduction in hydroxyl content. However there is reduction in bond length for the film deposited at −100 V as compared to other films resulting from structural changes. The disorder factor obtained from EXAFS measurement increases for films deposited at voltages beyond −125 V due to

  9. Sensitivities of statistical distribution model and diffusion kurtosis model in varying microstructural environments: a Monte Carlo study.

    Science.gov (United States)

    Lee, Chu-Yu; Bennett, Kevin M; Debbins, Josef P

    2013-05-01

    The aim of this study was to investigate the microstructural sensitivity of the statistical distribution and diffusion kurtosis (DKI) models of non-monoexponential signal attenuation in the brain using diffusion-weighted MRI (DWI). We first developed a simulation of 2-D water diffusion inside simulated tissue consisting of semi-permeable cells and a variable cell size. We simulated a DWI acquisition of the signal in a volume using a pulsed gradient spin echo (PGSE) pulse sequence, and fitted the models to the simulated DWI signals using b-values up to 2500 s/mm(2). For comparison, we calculated the apparent diffusion coefficient (ADC) of the monoexponential model (b-value=1000 s/mm(2)). In separate experiments, we varied the cell size (5-10-15 μm), cell volume fraction (0.50-0.65-0.80), and membrane permeability (0.001-0.01-0.1mm/s) to study how the fitted parameters tracked simulated microstructural changes. The ADC was sensitive to all the simulated microstructural changes except the decrease in membrane permeability. The ADC increased with larger cell size, smaller cell volume fraction, and larger membrane permeability. The σstat of the statistical distribution model increased exclusively with a decrease in cell volume fraction. The Kapp of the DKI model was exclusively increased with decreased cell size and decreased with increasing membrane permeability. These results suggest that the non-monoexponential models of water diffusion have different, specific microstructural sensitivity, and a combination of the models may give insights into the microstructural underpinning of tissue pathology.

  10. Geology and depositional environments of the Guadalupian rocks of the northern Del Norte Mountains, West Texas

    Science.gov (United States)

    Rudine, S.F.; Wardlaw, B.R.; Rohr, D.M.; Grant, R.E.

    2000-01-01

    The Guadalupian rocks of the northern Del Norte Mountains were deposited in a foreland basin between land of the Marathon orogen and a carbonate shoal established on the geanticline separating the foreland basin from the Delaware basin. Deposition was alternately influenced by coarse clastic input from the orogen and carbonate shoal, which interrupted shallow basinal siltstone depletion. Relatively deeper-water deposition is characterized by carbonate input from the shoal, and relatively shallow-water deposition is characterized by sandstone input from the orogen. Deposition was in five general transgressive-regressive packages that include (1) the Road Canyon Formation and the first siltstone member and first sandstone member of the Word Formation, (2) the second siltstone member, Appel Ranch Member, and limy sandy siltstone member of the Word Formation, (3) the Vidrio Formation, (4) the lower and part of the middle members of the Altuda Formation, and (5) part of the middle and upper members of the Altuda Formation.

  11. The Empirical Study of Japanese Deposit Withdrawal Behaviors on Unstable Financial Environment

    Directory of Open Access Journals (Sweden)

    Toshihiko Takemura

    2011-01-01

    Full Text Available Problem statement: We need to analyze to withdrawal behavior rather than deposit behavior on the situation which financial institutions might fail. However, there are few studies on withdrawal behavior although there are various studies on individual deposit behavior. Approach: Our purpose of this study is to investigate relationships between individual’s deposit withdrawal behavior and economic and psychological factors using micro data from an Internet (Web-based survey. Results: We confirm that individual’s withdrawal behavior is strongly affected by not only economic factors, but also psychological factors. In many cases, sign of estimated coefficient of economic factors are consistent with theory of economic behavior. In addition, effects of psychological factors such as degree of trust in information sources and degree of risk aversion are not uniformly against individual’s deposit-withdrawal behavior. Furthermore, we confirm that the probability that they carelessly withdraw their deposits tends to be lower if individuals correctly understand Japanese deposit insurance scheme. Conclusions: For reducing the ratio of individuals who do not correctly understand the Japanese deposit insurance scheme, we propose that the government should announce and educate the scheme to people strongly.

  12. Impact of nitrogen deposition on forest and lake food webs in nitrogen-limited environments.

    Science.gov (United States)

    Meunier, Cédric L; Gundale, Michael J; Sánchez, Irene S; Liess, Antonia

    2016-01-01

    Increased reactive nitrogen (Nr ) deposition has raised the amount of N available to organisms and has greatly altered the transfer of energy through food webs, with major consequences for trophic dynamics. The aim of this review was to: (i) clarify the direct and indirect effects of Nr deposition on forest and lake food webs in N-limited biomes, (ii) compare and contrast how aquatic and terrestrial systems respond to increased Nr deposition, and (iii) identify how the nutrient pathways within and between ecosystems change in response to Nr deposition. We present that Nr deposition releases primary producers from N limitation in both forest and lake ecosystems and raises plants' N content which in turn benefits herbivores with high N requirements. Such trophic effects are coupled with a general decrease in biodiversity caused by different N-use efficiencies; slow-growing species with low rates of N turnover are replaced by fast-growing species with high rates of N turnover. In contrast, Nr deposition diminishes below-ground production in forests, due to a range of mechanisms that reduce microbial biomass, and decreases lake benthic productivity by switching herbivore growth from N to phosphorus (P) limitation, and by intensifying P limitation of benthic fish. The flow of nutrients between ecosystems is expected to change with increasing Nr deposition. Due to higher litter production and more intense precipitation, more terrestrial matter will enter lakes. This will benefit bacteria and will in turn boost the microbial food web. Additionally, Nr deposition promotes emergent insects, which subsidize the terrestrial food web as prey for insectivores or by dying and decomposing on land. So far, most studies have examined Nr -deposition effects on the food web base, whereas our review highlights that changes at the base of food webs substantially impact higher trophic levels and therefore food web structure and functioning. © 2015 John Wiley & Sons Ltd.

  13. Effect of recurrent sediment resuspension-deposition events on bioavailability of polycyclic aromatic hydrocarbons in aquatic environments

    Science.gov (United States)

    Dong, Jianwei; Xia, Xinghui; Wang, Minghu; Xie, Hui; Wen, Jiaojiao; Bao, Yimeng

    2016-09-01

    To investigate the effect of recurrent sediment resuspension-deposition events (RSRDEs) on bioavailability of polycyclic aromatic hydrocarbons (PAHs) in aquatic environments, a modified device was used to simulate three resuspension-deposition events with the sediment collected from the Yellow River. The results showed that the dissolved organic carbon (DOC)-water distribution coefficients of PAHs decreased with time during the first resuspension-deposition period. It indicates that some PAHs associated with organic carbon (OC) in suspended sediment (SPS) desorbed with the release of OC and became DOC-associated PAHs in the overlying water, then the PAHs desorbed from the DOC and became freely dissolved. After first 2-h suspension, only 1.90% of phenanthrene, 2.98% of pyrene, and 0.33% of chrysene in the overlying water came from pore-water; at least 61.6%, 89.6%, and 95.3% came from DOC-associated PAHs in SPS and the rests were released from the insoluble OC in SPS. The maximum desorption ratios in the original sediment were 20%, 12%, and 14% for phenanthrene, pyrene, and chrysene, respectively during the first resuspension-deposition event. The SPS concentration followed the sequence of the third > second > first resuspension event. This was because RSRDEs changed the SPS particle size and enhanced floc formation. There was no significant difference in the total dissolved PAH concentrations among the three resuspension events, while their freely dissolved concentrations followed the sequence of the third > second > first resuspension event. During deposition periods, more than half of the total/freely dissolved PAHs released during suspension still existed in the overlying water after 70-h deposition. This study suggests that the RSRDEs will increase the bioavailability of PAHs in aquatic environments, especially near the sediment-water interface, and the potential effects of PAHs during RSRDEs on fish/human in rivers and lakes should be considered in future

  14. Palynostratigraphy, palynofacies and depositional environment of a lignite-bearing succession at Surkha Mine, Cambay Basin, north-western India

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    Monga Priyanka

    2015-12-01

    Full Text Available The paper reports palynology and palynofacies studies of lignite-bearing sediments exposed in an opencast mine succession at Surkha, Bhavnagar District, in the coastal region of Gujarat, India. The study examined the relationships between the palynoflora, sedimentary organic matter and environment at the time of deposition of lignite and associated sediments. Based on dinoflagellate cyst biostratigraphy, the sedimentary succession is dated as early Eocene (Ypresian. Palynofacies studies helped reveal the palaeoenvironmental fluctuations. The dominance of angiosperm pollen grains, freshwater algae, microthyraceous fungi and a large share of land debris in the lower part of the succession suggests a freshwater swamp environment of deposition for the basal lignite facies. Two cenozones - Matanomadiasulcites maximus and Lakiapollis ovatus - were identified in the lower lignite facies, determined from the dominance of these pollen grains in the palynological assemblages. The presence of angiosperm pollen grains and pteridophyte spores in the carbonaceous shale horizon above the lignite facies indicates a change in the depositional regime from freshwater swamp to lagoonal. This was identified as the Arecipites wodehousei cenozone due to its numerical abundance in the assemblage. Dinoflagellate cyst abundance and diversity, and microforaminiferal test linings along with well-sorted terrestrial debris in the mudstone in the upper part of the succession suggest a more open marine estuarine type of depositional environment. The Homotryblium complex along with Cordospheridium fibrospinosum, Kenleyia sp., and Thalassiphora pelagica dinoflagellate cysts are the main representatives of this zone, determined as the Homotryblium tenuispinosum cenozone. The changing depositional settings (freshwater swamp-lagoonal-estuarine along the vertical succession indicate a marine transgression in this region. Results from palynological studies of early Palaeogene

  15. Dispersion and dry and wet deposition of PAHs in an atmospheric environment.

    Science.gov (United States)

    Ozaki, N; Nitta, K; Fukushima, T

    2006-01-01

    The atmospheric concentration and dry and wet deposition were measured for particulate matter (PM) and polycyclic aromatic hydrocarbons (PAHs) from August to December in Higashi-Hiroshima City, Japan. PM concentration of fine particles (0.6-7 microm) was 5.7-75.1 micro m(-3), and coarse particles (> 7 microm) was 2.2-22.3 microg m(-3). Total PAHs concentration of fine particles was 0.14-16.3 ng m(-3), and coarse particles was 0.01-0.77 ng m(-3). Their concentration increased on non-rainy days and decreased rapidly on rainy days. For seasonal fluctuations of PAHs, their concentrations decreased from summer to winter, and the rate of decrease was more distinct for fine particles. For total (dry + wet) depositions, the PM flux was 1.9-11.2 mg m(-2) d(-1), and the total PAHs flux was 1.9-97.2 ng m(-3) d(-1). From these measurements, the yearly total loading of PAHs was estimated for the particle phase. Total loading was 28 microg m(-2) y(-1) for the dry deposition and 52 mg m(-2) y(-1) for the wet deposition. The loading of the wet deposition was comparable to those of the dry deposition for all ring numbers.

  16. Depositional environments and sequence stratigraphy of the Bahram Formation (middleelate Devonian) in north of Kerman, south-central Iran

    Institute of Scientific and Technical Information of China (English)

    Afshin Hashmie; Ali Rostamnejad; Fariba Nikbakht; Mansour Ghorbanie; Peyman Rezaie; Hossien Gholamalian

    2016-01-01

    This study is focused on sedimentary environments, facies distribution, and sequence stratigraphy. The facies and sequence stratigraphic analyses of the Bahram Formation (middleelate Devonian) in south-central Iran are based on two measured stratigraphic sections in the southern Tabas block. The Bah-ram Formation overlies red sandstones Padeha Formation in sections Hutk and Sardar and is overlain by Carboniferous carbonate deposits of Hutk Formation paraconformably, with a thickness of 354 and 386 m respectively. Mixed siliciclastic and carbonate sediments are present in this succession. The field observations and laboratory studies were used to identify 14 micro/petrofacies, which can be grouped into 5 depositional environments: shore, tidal flat, lagoon, shoal and shallow open marine. A mixed carbonate-detrital shallow shelf is suggested for the depositional environment of the Bahram Formation which deepens to the east (Sardar section) and thins in southern locations (Hutk section). Three 3rd-order cyclic siliciclastic and carbonate sequences in the Bahram Formation and one sequence shared with the overlying joint with Hutk Formation are identified, on the basis of shallowing upward patterns in the micro/pertofacies.

  17. Study of the crystallographic phase change on copper (I) selenide thin films prepared through chemical bath deposition by varying the pH of the solution

    Science.gov (United States)

    Sandoval-Paz, M. G.; Rodríguez, C. A.; Porcile-Saavedra, P. F.; Trejo-Cruz, C.

    2016-07-01

    Copper (I) selenide thin films with orthorhombic and cubic structure were deposited on glass substrates by using the chemical bath deposition technique. The effects of the solution pH on the films growth and subsequently the structural, optical and electrical properties of the films were studied. Films with orthorhombic structure were obtained from baths wherein both metal complex and hydroxide coexist; while films with cubic structure were obtained from baths where the metal hydroxide there is no present. The structural modifications are accompanied by changes in bandgap energy, morphology and electrical resistivity of the films.

  18. Geochemical Proxies as an Effective Tool for Determining Depositional Environments for Burgess Shale-Type Fossil Localities

    Science.gov (United States)

    Powell, W.; Handle, K.

    2012-04-01

    A variety of models have been presented to account for the arrest of decay processes in Burgess Shale-type (BST) fossil beds. These models include sustained anoxia, fluctuating oxyclines, and hypersaline brines. Despite being questioned in the published literature, patterns in redox-sensitive metals may differentiate between these chemical environments of deposition. Accordingly, the redox indices V versus Al, V/Sc, Ni/Al, Ni/Co, and Mo were applied to two well-documented North American BST localities: 1) the Wheeler Formation (Utah, USA) with palaeontological characteristics indicating deposition within a fluctuating oxycline; and 2) the Burgess Shale (British Columbia, Canada) with field evidence indicating an association of fossil deposits with hypersaline brine pools. In addition, the chemical characteristics of the Kinzers Formation (Pennsylvania, USA), a BST fossil locality in which details of depositional environment are unclear due to limited outcrop exposure, were compared to those of the Wheeler and Burgess Shale formations. A set of eighty-four Wheeler Shale samples yielded a range of Ni/Co values from 0.6 to 10.5, and V/Sc values up to 27.9. Barren shales cluster along the line that defines the lithogenic maximum for V, whereas fossiliferous samples yielded a scattered distribution of V versus Al values above the lithogenic maximum. Molybdenum content was Shale samples. These data are consistent with deposition under a range of redox conditions, with fossils (both BST and trilobites) correlating with low-oxygen environments. In contrast, a set of 53 samples from the Burgess Shale and associated units yielded a restricted range of both Ni/Co (Burgess Shale strata beneath an oxygenated water column. Geochemical palaeo-redox proxies are consistent with field relationships and palaeontological data. This demonstrates that geochemical proxies can be applied effectively to BST fossil-bearing strata. Two units within the Kinzers Formation were studied: 1) the

  19. Palaeoecology and depositional environments of the Tendaguru Beds (Late Jurassic to Early Cretaceous, Tanzania

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    M. Aberhan

    2002-01-01

    Full Text Available The Late Jurassic to Early Cretaceous Tendaguru Beds (Tanzania, East Africa have been well known for nearly a century for their diverse dinosaur assemblages. Here, we present sedimentological and palaeontological data collected by the German-Tanzanian Tendaguru Expedition 2000 in an attempt to reconstruct the palaeo-ecosystems of the Tendaguru Beds at their type locality. Our reconstructions are based on sedimentological data and on a palaeoecological analysis of macroinvertebrates, microvertebrates, plant fossils and microfossils (ostracods, foraminifera, charophytes, palynomorphs. In addition, we included data from previous expeditions, particularly those on the dinosaur assemblages. The environmental model of the Tendaguru Beds presented herein comprises three broad palaeoenvironmental units in a marginal marine setting: (1 Lagoon-like, shallow marine environments above fair weather wave base and with evidence of tides and storms. These formed behind barriers such as ooid bar and siliciclastic sand bar complexes and were generally subject to minor salinity fluctuations. (2 Extended tidal flats and low-relief coastal plains. These include low-energy, brackish coastal lakes and ponds as well as pools and small fluvial channels of coastal plains in which the large dinosaurs were buried. Since these environments apparently were, at best, poorly vegetated, the main feeding grounds of giant sauropods must have been elsewhere. Presumably, tidal flats and coastal plains were visited by dinosaurs primarily during periods of drought. (3 Vegetated hinterland. Vegetation of this environment can only be inferred indirectly from plant material transported into the other depositional environments. Vegetation was dominated by a diverse conifer flora, which apparently formed part of the food source of large herbivorous sauropods. Evidence from various sources suggests a subtropical to tropical palaeoclimate, characterised by seasonal rainfall alternating with

  20. Global research collaboration and international education: Laser metal deposition of varying percent of Ti-6Al-4V + molybdenum on Ti64 substrate for biomedical/aerospace applications

    CSIR Research Space (South Africa)

    Kumpaty, S

    2016-11-01

    Full Text Available to a Ti-64 substrate surface in order to improve the durability for various biomedical/aerospace applications. Deposition of the powders was completed at the CSIR - National Laser Center, in Pretoria, South Africa. The characterization studies were...

  1. From the Field to the Classroom: A Web-Based Teaching Tool on Depositional Environments and Landscape Development

    Science.gov (United States)

    Krzic, M.; Watson, K.; Grand, S.; Crowley, C.; Dyanatkar, S.; Bomke, A.; Smith, S.

    2012-04-01

    The relationship between sedimentary deposits, landforms and soil profile development is difficult for students to grasp in a conventional classroom setting. The ideal way to solve this is to take the students on extended field trips; however, field trips are expensive, have to be conducted during specific time periods, and can only handle a limited number of students. The objective of this project was to bring the field to the classroom via a virtual, dynamic web-based teaching tool illustrating common depositional environments and associated landforms and soils. The teaching tool was largely based on video footage obtained in the Canadian Rocky Mountains and in the grasslands of the southern interior of British Columbia. The Canadian Rockies are undergoing rapid deglaciation and provided excellent examples of new glacial deposits and early landscape development processes. On the other hand, British Columbia's grasslands became ice-free about 10,000 years ago and were used to illustrate landscape evolution and post-glaciation soil profile development. To bring these two environments together, video footage of corresponding landforms was shot at both locations and edited into a series of short video clips illustrating the link between depositional processes, resulting landforms and soils and their post-glacial evolution. Soil scientists, survey specialists and geomorphologists provided live commentary. The teaching tool (http://soilweb.landfood.ubc.ca/landscape/) is an open-access website merging video clips, sound recordings, text, photos and graphics intended to help students situate landforms within their geomorphologic context. This online teaching resource allows students to observe, on their own time, conditions under which sediments are deposited and soils are formed, and to witness the transformation of a barren, glacial landscape into a vegetated soil landscape. The tool can be used in various geomorphology, soil, agriculture, forestry, and natural

  2. The origin of terrestrial pisoliths and pisolitic iron ore deposits: Raindrops and sheetwash in a semi-arid environment

    Science.gov (United States)

    Lascelles, Desmond F.

    2016-07-01

    Ooliths evidently form by chemical precipitation in limnic, paralic, fluvial and marine environments, pisoliths, however, appear to be restricted to terrestrial environments. Typically composed of iron, aluminium and manganese sesquioxides with minor admixtures of quartz and kaolinite, they are widely distributed in tropical to subtropical regions overlying deeply weathered soil profiles. Although iron-, aluminium- and manganese-rich end members are important sources of these metals, their genesis is still enigmatic; their formation has never been observed or produced experimentally and current models for their origin are little more than guesses. A new model is presented based on a unique personal observation in which pisoliths are formed by the action of charged raindrops during thunderstorms impacting on dry deeply weathered powdery soils. The pisoliths are transported across pediments by sheetwash, accumulating as thick deposits in the valley floors. Pisolites are characteristically unfossiliferous and typically clearly pedogenic. The absence of fine depositional layering, fossil seeds, leaves and pollen in pisolites is explained by bioturbation and the action of soil organisms during extended pedogenesis while the major coarse bedding features derive from erosional and depositional events in the evolution of the pediment. Pisolitic iron ores (aka channel iron deposits, CID) are a special case of transported pisolitic ferricrust that form an important resource of medium grade iron ore (57-60 wt% Fe) in the Pilbara Region of Western Australia. Apart from minor deposits in the northern Yilgarn Province of Western Australia, they have not been found elsewhere. They differ from normal transported ferricrust and terrestrial pisolites not only in the exceptionally high iron and low alumina and silica content but also in containing abundant fossilised wood particles.

  3. Late Holocene depositional environments and coastal evolution of the Mekong River Delta, Southern Vietnam

    Science.gov (United States)

    Lap Nguyen, Van; Ta, Thi Kim Oanh; Tateishi, Masaaki

    2000-08-01

    The Mekong River Delta in Southern Vietnam is a tide-dominated delta and has been formed by the Mekong River system. The sediments are dominantly fine grained and were deposited in the receiving basin with slight inclination of pre-existing deposits in the South China Sea and Gulf of Thailand. Around 6000 to 5000 yr BP maximum Holocene transgression occurred and seawaves surrounded uplands of the Late Pleistocene terrace, basement rock and weathered land in the northern parts of the delta. Double notches were undercut by seawaves on the limestone hill in Hatien at about 4.5 and 2.5 m above present sea level. Marine deposits prevailed throughout the delta. During the highstand and regressions of relative sea level over the last 4550 yr BP, delta progradation has produced a great flat-plain of 62,520 km 2. This extremely fast progradation could be due to: (a) very high sediment supply depositing in the slight inclination of the receiving basin; (b) neotectonic movements and relative sea-level changes; (c) widespread mangrove forests playing an important role to enhance sediment accumulation. Former mangrove marshy deposits were significantly developed in the Plain of Reeds and Longxuyen Quadrangle. Mangrove marshes have also been developing well in the Camau Peninsula and present coastlines. Moreover, regressions over the last 4550 yr BP have produced many distinct sets of relict beach ridges which are useful in distinguishing the former coastlines and evolutionary history of the delta.

  4. Impactites of the Yaxcopoil-1 drilling site, Chicxulub impact structure: Petrography, geochemistry, and depositional environment

    Science.gov (United States)

    Dressler, Burkhard O.; Sharpton, Virgil L.; Schwandt, Craig S.; Ames, Doreen

    2004-01-01

    The impact breccias encountered in drill hole Yaxcopoil-1 (Yax-1) in the Chicxulub impact structure have been subdivided into six units. The two uppermost units are redeposited suevite and suevite, and together are only 28 m thick. The two units below are interpreted as a ground surge deposit similar to a pyroclastic flow in a volcanic regime with a fine-grained top (unit 3; 23 m thick; nuee ardente) and a coarse breccia (unit 4; approx.15 m thick) below. As such, they consist of a melange of clastic matrix breccia and melt breccia. The pyroclastic ground surge deposit and the two units 5 and 6 below are related to the ejecta curtain. Unit 5 (approx.24 m thick) is a silicate impact melt breccia, whereas unit 6 (10 m thick) is largely a carbonate melt breccia with some clastic-matrix components. Unit 5 and 6 reflect an overturning of the target stratigraphy. The suevites of units 1 and 2 were deposited after emplacement of the ejecta curtain debris. Reaction of the super-heated breccias with seawater led to explosive activity similar to phreomagmatic steam explosion in volcanic regimes. This activity caused further brecciation of melt and melt fragments. The fallback suevite deposit of units 1 and 2 is much thinner than suevite deposits at larger distances from the center of the impact structure than the 60 km of the Yax-1 drill site. This is evidence that the fallback suevite deposit (units 1 and 2) originally was much thicker. Unit 1 exhibits sedimentological features suggestive of suevite redeposition. Erosion possibly has occurred right after the IUT impact due to seawater backsurge, but erosion processes spanning thousands of years may also have been active. Therefore, the top of the 100 m thick impactite sequence at Yaxcopoil, in our opinion, is not the K/T boundary.

  5. Impactites of the Yaxcopoil-1 drilling site, Chicxulub impact structure: Petrography, geochemistry, and depositional environment

    Science.gov (United States)

    Dressler, Burkhard O.; Sharpton, Virgil L.; Schwandt, Craig S.; Ames, Doreen

    2004-01-01

    The impact breccias encountered in drill hole Yaxcopoil-1 (Yax-1) in the Chicxulub impact structure have been subdivided into six units. The two uppermost units are redeposited suevite and suevite, and together are only 28 m thick. The two units below are interpreted as a ground surge deposit similar to a pyroclastic flow in a volcanic regime with a fine-grained top (unit 3; 23 m thick; nuee ardente) and a coarse breccia (unit 4; approx.15 m thick) below. As such, they consist of a melange of clastic matrix breccia and melt breccia. The pyroclastic ground surge deposit and the two units 5 and 6 below are related to the ejecta curtain. Unit 5 (approx.24 m thick) is a silicate impact melt breccia, whereas unit 6 (10 m thick) is largely a carbonate melt breccia with some clastic-matrix components. Unit 5 and 6 reflect an overturning of the target stratigraphy. The suevites of units 1 and 2 were deposited after emplacement of the ejecta curtain debris. Reaction of the super-heated breccias with seawater led to explosive activity similar to phreomagmatic steam explosion in volcanic regimes. This activity caused further brecciation of melt and melt fragments. The fallback suevite deposit of units 1 and 2 is much thinner than suevite deposits at larger distances from the center of the impact structure than the 60 km of the Yax-1 drill site. This is evidence that the fallback suevite deposit (units 1 and 2) originally was much thicker. Unit 1 exhibits sedimentological features suggestive of suevite redeposition. Erosion possibly has occurred right after the IUT impact due to seawater backsurge, but erosion processes spanning thousands of years may also have been active. Therefore, the top of the 100 m thick impactite sequence at Yaxcopoil, in our opinion, is not the K/T boundary.

  6. Microfacies characteristics, sedimentary environments and sequence stratigraphy of Upper Cretaceous deposits in northwest of Nehbandan (Basiran section

    Directory of Open Access Journals (Sweden)

    Azadeh Bordbar

    2015-09-01

    Full Text Available   Introduction   The Basiran stratigraphic section is located about 160 km northwest of Nehbandan.The section was measured in detail at 59 06 30 N and 31 52 50 E. Nehbandan area with respect to fourfold geological subdivision of Iran is part of Central Iran that is located in the eastern flank of Lut Block which first time are studied by Stocklin et al.in 1972. Gorgij (2001 stratigraphically and paleontologically investigate Upper Cretaceous deposits in Mighan and Basiran sections. Upper Cretaceous deposits in in this area consists of 275m conglomerate,alternation of conglomerate-sandstone, sandy limestone -marl and limy marl, marl with intercalation of limestone-sandy limestone thin beds and medium-bedded to massive limestone. Microfacies analysis led to the recognition of 9 microfacies that are related to 5 belts Coast, tidal flat, lagoon, shoal, shallow open marine and deep open marine environments. Main part of the section are deposited in the open marine environment that consist of marl,marly limestone and limestone. The doals of this study are : (1 describing and determining main carbonate and siliciclastic microfacies of late Cretaceous deposits (2 interpreting and providing depositional model for reconstruction of its paleoenvironmental setting based on microfacies characteristics (3 dividing the section based on lithostratigraphic principles and (4 recognizing a sequence stratigraphic model of this successions based on the vertical variation of facies,stratal key beds and stratal packing pattern.       Material and Method   The Basiran section as a complete stratigraphic section was measured and described. Up to 68 samples (indicated by KB1 to KB68 were collected and 170 thin sections are prepared. Based on field observations, sedimentological characteristics, parasequence stacking patterns, sequence boundary types and other key stratigraphical surfaces are identified and were obtained. Scheme of Dunham (1962 and Embry

  7. Microfacies characteristics, sedimentary environments and sequence stratigraphy of Upper Cretaceous deposits in northwest of Nehbandan (Basiran section

    Directory of Open Access Journals (Sweden)

    Mohammad nabi Gorgij

    2015-10-01

    Full Text Available Introduction   The Basiran stratigraphic section is located about 160 km northwest of Nehbandan.The section was measured in detail at 59 06 30 N and 31 52 50 E. Nehbandan area with respect to fourfold geological subdivision of Iran is part of Central Iran that is located in the eastern flank of Lut Block which first time are studied by Stocklin et al.in 1972. Gorgij (2001 stratigraphically and paleontologically investigate Upper Cretaceous deposits in Mighan and Basiran sections. Upper Cretaceous deposits in in this area consists of 275m conglomerate,alternation of conglomerate-sandstone, sandy limestone -marl and limy marl, marl with intercalation of limestone-sandy limestone thin beds and medium-bedded to massive limestone. Microfacies analysis led to the recognition of 9 microfacies that are related to 5 belts; Coast, tidal flat, lagoon, shoal, shallow open marine and deep open marine environments. Main part of the section are deposited in the open marine environment that consist of marl,marly limestone and limestone. The doals of this study are : (1 describing and determining main carbonate and siliciclastic microfacies of late Cretaceous deposits (2 interpreting and providing depositional model for reconstruction of its paleoenvironmental setting based on microfacies characteristics (3 dividing the section based on lithostratigraphic principles and (4 recognizing a sequence stratigraphic model of this successions based on the vertical variation of facies,stratal key beds and stratal packing pattern.       Material and Method   The Basiran section as a complete stratigraphic section was measured and described. Up to 68 samples (indicated by KB1 to KB68 were collected and 170 thin sections are prepared. Based on field observations, sedimentological characteristics, parasequence stacking patterns, sequence boundary types and other key stratigraphical surfaces are identified and were obtained. Scheme of Dunham (1962 and Embry and Klovan

  8. Relationship between depositional environment and potential of lacustrine source rock; Koshosei kongengan no taiseki kankyo to kongengan potensharu no kankei

    Energy Technology Data Exchange (ETDEWEB)

    Tsuga, I.; Hatako, K.; Yokoyama, Y. [Japan National Oil Corp., Tokyo (Japan)

    1998-10-30

    In order to clarity the relationship potential of lacustrine source rock and depositional environment, cutting samples of the well drilled offshore Tenasserim, Myanmer were investigated for geochemical analysis. This basin is half-graven type basin formed in Tertiary and consist of terrestrial {approx} shallow marine sediments. According to palaenvironmental analysis, freshwater {approx} brackishwater lacustrine environment was spread during Miocene. Generally, source rock of this lacustrine sediments have high potential that TOC contents are 0.58 {approx} 3.61 % (Fair {approx} Very Good) and HI value area 136 {approx} 686 mg/g (Good {approx} Very Good). It are especially high that source rock potential of lacustrine sediments were influenced by brackishwater. As a results of maceral analysis, it indicated that source rock potential correlate closely with maceral compassion. High potential samples were characterized high amorphinite content. This result suggest that brackishwater influence develop anoxic environment and prevent organic matter from oxidizing. (author)

  9. The impact and significance of tephra deposition on a Holocene forest environment in the North Cascades, Washington, USA

    Science.gov (United States)

    Egan, Joanne; Fletcher, William J.; Allott, Tim E. H.; Lane, Christine S.; Blackford, Jeff J.; Clark, Douglas H.

    2016-04-01

    High-resolution palaeoecological analyses (stratigraphy, tephra geochemistry, radiocarbon dating, pollen and ordination) were used to reconstruct a Holocene vegetation history of a watershed in the Pacific Northwest of America to evaluate the effects and duration of tephra deposition on a forest environment and the significance of these effects compared to long-term trends. Three tephra deposits were detected and evaluated: MLF-T158 and MLC-T324 from the climactic eruption of Mount Mazama, MLC-T480 from a Late Pleistocene eruption of Mount Mazama and MLC-T485 from a Glacier Peak eruption. Records were examined from both the centre and fringe of the basin to elucidate regional and local effects. The significance of tephra impacts independent of underlying long-term trends was confirmed using partial redundancy analysis. Tephra deposition from the climactic eruption of Mount Mazama approximately 7600 cal. years BP caused a significant local impact, reflected in the fringe location by changes to open habitat vegetation (Cyperaceae and Poaceae) and changes in aquatic macrophytes (Myriophyllum spicatum, Potamogeton, Equisetum and the alga Pediastrum). There was no significant impact of the climactic Mazama tephra or other tephras detected on the pollen record of the central core. Changes in this core are potentially climate driven. Overall, significant tephra fall was demonstrated through high resolution analyses indicating a local effect on the terrestrial and aquatic environment, but there was no significant impact on the regional forest dependent of underlying environmental changes.

  10. Depositional environment of a fan delta in a Vistulian proglacial lake (Skaliska Basin, north-eastern Poland

    Directory of Open Access Journals (Sweden)

    Woronko Barbara

    2013-06-01

    Full Text Available The study reconstructed the environment of a fan delta filling the vast end depression of the Skaliska Basin, and its overlying aeolian deposits. The formation of the large fan delta is associated with the presence of an ice-dammed lake functioning during the retreat of the Vistulian Glaciation (MIS 2. The examined material was collected from five boreholes. Sediments were analysed for their granulometric composition and subjected to analyses of frosting and rounding of quartz grains. Grain size analysis showed that the fan delta deposits are built of sand sediments of very low lateral and vertical variability. The fan delta was supplied with fluvioglacial sediments. Accumulation of sediments occurred in shallow water with a very low-gradient slope. The exposed fan delta became a site conducive to aeolian processes after the lake waters fell and the Skaliska Basin depression dried. Dune deposits overlying the fan were affected by short-distance transport so they did not acquire features typical for aeolian deposits.

  11. Assessing deposition levels of 55Fe, 60Co and 63Ni in the Ignalina NPP environment

    DEFF Research Database (Denmark)

    Gudelis, A.; Druteikienė, R.; Lukšienė, B.

    2010-01-01

    Two RBMK-1500 reactor units operated in Lithuania in the 1987–2004 period (one of them was stopped for decommissioning in 2004). This study presents a preliminary investigation of surface deposition density levels of 55Fe and 63Ni in moss samples collected in the close vicinity of the Ignalina NPP...

  12. Lithofacies, depositional environments, and regional stratigraphy of the lower Eocene Ghazij Formation, Balochistan, Pakistan

    Science.gov (United States)

    Johnson, Edward A.; Warwick, P.D.; Roberts, S.B.; Khan, I.H.

    1999-01-01

    A regional stratigraphic investigation of one of the most important coal-bearing lithostratigraphic units in Pakistan, the report includes sedimentologic observations taken from outcrops and measured sections, information derived from petrographic and paleontologic analyses, depositional interpretations, and descriptions of regional trends.

  13. The depositional environments of Schöningen 13 II-4 and their archaeological implications.

    Science.gov (United States)

    Stahlschmidt, Mareike C; Miller, Christopher E; Ligouis, Bertrand; Goldberg, Paul; Berna, Francesco; Urban, Brigitte; Conard, Nicholas J

    2015-12-01

    Geoarchaeological research at the Middle Pleistocene site of Schöningen 13 II-4, often referred to as the Speerhorizont, has focused on describing and evaluating the depositional contexts of the well-known wooden spears, butchered horses, and stone tools. These finds were recovered from the transitional contact between a lacustrine marl and an overlying organic mud, originally thought to be a peat that accumulated in place under variable moisture conditions. The original excavators proposed that hominin activity, including hunting and butchery, occurred on a dry lake shore and was followed by a rapid sedimentation of organic deposits that embedded and preserved the artifacts. Our geoarchaeological analysis challenges this model. Here, we present evidence that the sediments of Schöningen 13 II-4 were deposited in a constantly submerged area of a paleolake. Although we cannot exclude the possibility that the artifacts were deposited during a short, extreme drying event, there are no sedimentary features indicative of surface exposure in the sediments. Accordingly, this paper explores three main alternative models of site formation: anthropogenic disposal of materials into the lake, a geological relocation of the artifacts, and hunting or caching on lake-ice. These models have different behavioral ramifications concerning hominin knowledge and exploitation of the landscape and their subsistence strategies.

  14. Lithofacies Associations and Depositional Environments of the Neogene Molasse succession, Pishin Belt, northwestern Pakistan

    DEFF Research Database (Denmark)

    Kasi, Aimal K.; Kassi, Akhtar M.; Friis, Henrik

    Formation and Oligocene Khojak Formation. The Early to Middle Miocene Dasht Murgha group comprises Zone-III, the Late Miocene-Pliocene Malthanai formation comprises Zone-IV, the Pleistocene Bostan Formation makes Zone-V, and the flat-laying Holocene deposits of the Zhob Valley comprise Zone-VI. The Neogene...

  15. Sedimentary facies and depositional environments related to Gondwana glaciation in Batovi and Suspiro regions, Rio Grande Do Sul, Brazil

    Science.gov (United States)

    Tomazelli, Luiz José; Soliani, Enio

    1997-07-01

    Sedimentary facies were produced by Late Paleozoic Gondwana ice sheets in the Batovi and Suspiro regions, Rio Grande do Sul State, southern Brazil. The glaciogenic sediments, assigned to the Itararé Group of Paraná Basin, are the result of processes related to the subglacial, supraglacial and proglacial (ice-contact, glaciofluvial and glaciolacustrine) environments of the glacial depositional system. Several features developed by the action of glaciers were identified in the studied outcrops: striated and grooved pavements; striated, polished and faceted stones; finely laminated rhythmites bearing dropstones (varvites); erratic clasts and deposits exhibiting deformational structures such as folds, normal and reverse faults, and beds with abnormal dips. The available evidence suggests that the glacial episodes took place in a terrestrial (continental) context, far from direct marine influence.

  16. Does the Effect of Micro-Environmental Factors on a Street's Appeal for Adults' Bicycle Transport Vary across Different Macro-Environments? An Experimental Study.

    Science.gov (United States)

    Mertens, Lieze; Van Cauwenberg, Jelle; Ghekiere, Ariane; Van Holle, Veerle; De Bourdeaudhuij, Ilse; Deforche, Benedicte; Nasar, Jack; Van de Weghe, Nico; Van Dyck, Delfien

    2015-01-01

    Characteristics of the physical environment can be classified into two broad categories: macro- ("raw" urban planning features influenced on a regional level) and micro- (features specifically within a streetscape influenced on a neighborhood level) environmental factors. In urban planning applications, it is more feasible to modify conditions at the neighborhood level than at the regional level. Yet for the promotion of bicycle transport we need to know whether relationships between micro-environmental factors and bicycle transport depend on different types of macro-environments. This study aimed to identify whether the effect of three micro-environmental factors (i.e., evenness of the cycle path surface, speed limits and type of separation between cycle path and motorized traffic) on the street's appeal for adults' bicycle transport varied across three different macro-environments (i.e., low, medium and high residential density street). In total, 389 middle-aged adults completed a web-based questionnaire consisting of socio-demographic characteristics and a series of choice tasks with manipulated photographs, depicting two possible routes to cycle along. Conjoint analysis was used to analyze the data. Although the magnitude of the overall effects differed, in each macro-environment (i.e., low, medium and high residential density), middle-aged adults preferred a speed limit of 30 km/h, an even cycle path surface and a hedge as separation between motorized traffic and the cycle path compared to a speed limit of 50 or 70 km/h, a slightly uneven or uneven cycle path surface and a curb as separation or no separation between motorized traffic and the cycle path. Our results suggest that irrespective of the macro-environment, the same micro-environmental factors are preferred in middle-aged adults concerning the street's appeal for bicycle transport. The controlled environment simulations in the experimental choice task have the potential to inform real life

  17. Does the Effect of Micro-Environmental Factors on a Street’s Appeal for Adults’ Bicycle Transport Vary across Different Macro-Environments? An Experimental Study

    Science.gov (United States)

    Mertens, Lieze; Van Cauwenberg, Jelle; Ghekiere, Ariane; Van Holle, Veerle; De Bourdeaudhuij, Ilse; Deforche, Benedicte; Nasar, Jack; Van de Weghe, Nico; Van Dyck, Delfien

    2015-01-01

    Background Characteristics of the physical environment can be classified into two broad categories: macro- (“raw” urban planning features influenced on a regional level) and micro- (features specifically within a streetscape influenced on a neighborhood level) environmental factors. In urban planning applications, it is more feasible to modify conditions at the neighborhood level than at the regional level. Yet for the promotion of bicycle transport we need to know whether relationships between micro-environmental factors and bicycle transport depend on different types of macro-environments. This study aimed to identify whether the effect of three micro-environmental factors (i.e., evenness of the cycle path surface, speed limits and type of separation between cycle path and motorized traffic) on the street’s appeal for adults’ bicycle transport varied across three different macro-environments (i.e., low, medium and high residential density street). Methods In total, 389 middle-aged adults completed a web-based questionnaire consisting of socio-demographic characteristics and a series of choice tasks with manipulated photographs, depicting two possible routes to cycle along. Conjoint analysis was used to analyze the data. Results Although the magnitude of the overall effects differed, in each macro-environment (i.e., low, medium and high residential density), middle-aged adults preferred a speed limit of 30 km/h, an even cycle path surface and a hedge as separation between motorized traffic and the cycle path compared to a speed limit of 50 or 70 km/h, a slightly uneven or uneven cycle path surface and a curb as separation or no separation between motorized traffic and the cycle path. Conclusions Our results suggest that irrespective of the macro-environment, the same micro-environmental factors are preferred in middle-aged adults concerning the street’s appeal for bicycle transport. The controlled environment simulations in the experimental choice task

  18. Microfossils and molecular records in oil shales of the Songliao Basin and implications for paleo-depositional environment

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Several oil shale beds, over 10 m thick, occur at the base of the first member of the Upper Cretaceous Qingshankou Formation (K2qn1) in the Songliao Basin. They act both as excellent source rocks for conventional oil and as potential oil deposit for shale oil production. Here we combine micropaleon-tology with organic geochemistry to investigate the paleo-depositional environment and organic source characteristics of the oil shales and black shales. Our results indicate that algal remains are dominant microfossils in K2qn1 oil shales, and their relatively high abundance suggests a major algal thriving event during the oil shale deposition. The presence of fresh water and brackish water species, Sentusidinium, Vesperopsis and Nyktericysta, and marine or brackish water deltaic and lagoonal species such as Kiokansium and Dinogymniopsis demonstrate that this paleo-continental lake was influenced by marine transgressions at the time of K2qn1 oil shale formation. The extremely low pristine/phytane ratios, relatively high abundance of gammacerane and 4-methyl steranes, and low δ 13C values of C14-C37 n-alkanes in the oil shale organic extracts indicate the deposition of oil shales in anoxic and highly stratified water columns and the significant contribution of lacustrine algae to sedimentary organic matter. High molecular-weight paraffinic hydrocarbons with unusually high abundance of nC43, nC45, and nC47 may be related to special algal species associated with marine transgression events. The giant water body of Songliao paleo-lake and the change in the organic and chemical environment (such as nutrition source and water column salinity) associated with seawater transgression into the lake are among the most important reasons for oil shales in the Songliao Basin being different from mudstone and oil shale in other rifted basins.

  19. Depositional environments of Late Triassic lake, east-central New Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Hester, P.M. (Bureau of Land Management, Albuquerque, NM (USA))

    1989-09-01

    The Redonda Member of the Chinle Formation represents deposition in a large, polymictic lake during the Late Triassic (Norian) in east-central New Mexico. This study documents and defines an extensive lacustrine system situated in western Pangaea which was influenced by both tectonic and climatic events. Areal extent of the lake may have been as much as 5,000 km{sup 2}.

  20. Stress corrosion cracking of austenitic weld deposits in a salt spray environment

    Science.gov (United States)

    Cai, J. B.; Yu, C.; Shiue, R. K.; Tsay, L. W.

    2015-10-01

    ER 308L and 309LMo were utilized as the filler metals for the groove and overlay welds of a 304L stainless steel substrate, which was prepared via a gas tungsten arc-welding process in multiple passes. U-bend and weight-loss tests were conducted by testing the welds in a salt spray containing 10 wt% NaCl at 120 °C. The dissolution of the skeletal structure in the fusion zone (FZ) caused the stress corrosion cracking (SCC) of the weld. The FZ in the cold-rolled condition showed the longest single crack length in the U-bend tests. Moreover, sensitization treatment at 650 °C for 10 h promoted the formation of numerous fine cracks, which resulted in a high SCC susceptibility. The weight loss of the deposits was consistent with the SCC susceptibility of the welds in a salt spray. The 309LMo deposit was superior to the 308L deposit in the salt spray.

  1. Phosphatic Permian rocks of the Adobe Range, Nevada, and their environment of deposition

    Science.gov (United States)

    Ketner, Keith Brindley

    1979-01-01

    Permian sedimentary rocks in the Adobe range, northern Nevada, are phosphatic, and although the particles of phosphate are relatively more disseminated, they closely resemble the rocks of the Phosphoria Formation. In the northern Adobe Range, where the entire Permian sequence is approximately correlative with the Phosphoria Formation, it is 200 m thick and averages 1.7 percent P2O5 . In the southern Adobe Range, the Permian sequence is more than 1,700 m thick, and the upper half which is roughly correlative with the Phosphoria Formation averages more than 2 percent P2O5. Some thin beds in rocks of Permian age contain more than 20 percent P2O5. Phosphatic rocks of the Adobe Range were deposited in shallow water among islands in the western part of the epicontinental Phosphoria sea. The continental margin and the open ocean lay far to the west. At the same time, the Phosphoria Formation was being deposited in the eastern and central parts of the Phosphoria sea. Theories based on the work of Kasakov done in 1937 relating phosphate deposition directly to sites of upwelling oceanic waters are questioned. Nondeposition of diluent materials such as detritus and carbonate is probably of more importance in producing phosphate in economic concentrations than is geographic position with respect to upwelling waters.

  2. Depositional environment, organic matter characterization and hydrocarbon potential of Middle Miocene sediments from northeastern Bulgaria (Varna-Balchik Depression

    Directory of Open Access Journals (Sweden)

    Zdravkov Alexander

    2015-10-01

    Full Text Available The depositional environments and hydrocarbon potential of the siliciclastic, clayey and carbonate sediments from the Middle Miocene succession in the Varna-Balchik Depression, located in the south-eastern parts of the Moesian Platform, were studied using core and outcrop samples. Based on the lithology and resistivity log the succession is subdivided from base to top into five units. Siliciclastic sedimentation prevailed in the lower parts of units I and II, whereas their upper parts are dominated by carbonate rocks. Unit III is represented by laminated clays and biodetritic limestone. Units IV and V are represented by aragonitic sediments and biomicritic limestones, correlated with the Upper Miocene Topola and Karvuna Formations, respectively. Biogenic silica in the form of diatom frustules and sponge spicules correlates subunit IIa and unit III to the lower and upper parts of the Middle Miocene Euxinograd Formation. Both (subunits contain organic carbon contents in the order of 1 to 2 wt. % (median: 0.8 for subunit IIa; 1.3 for unit III, locally up to 4 wt. %. Based on Hydrogen Index values (HI and alkane distribution pattern, the kerogen is mainly type II in subunit IIa (average HI= 324 mg HC/g TOC and type III in unit III (average HI ~200 mg HC/g TOC. TOC and Rock Eval data show that subunit IIa holds a fair (to good hydrocarbon generative potential for oil, whereas the upper 5 m of unit III holds a good (to fair potential with the possibility to generate gas and minor oil. The rocks of both units are immature in the study area. Generally low sulphur contents are probably due to deposition in environments with reduced salinity. Normal marine conditions are suggested for unit III. Biomarker composition is typical for mixed marine and terrestrial organic matter and suggests deposition in dysoxic to anoxic environments.

  3. 贵州省瓮福磷矿沉积环境及矿床成因探讨%Sedimentary environment and deposit genesis of Wengfu phosphorus deposit in Guizhou

    Institute of Scientific and Technical Information of China (English)

    叶德书; 赵爽; 陈海; 钟祖峰

    2014-01-01

    The favorable location of sediment of Wengfu phosphorus deposit is subtidal bay shoal milieu in-stead of tidal flat.The size of bay controls the scale of deposit,and different beach energy results in different structural genesis types of phosphate ores.The structure of ores varies from coarse-grained to fine-grained gelatin-fine-grained-arene and arene,and the color of rocks varies from taupe and black (multi-terrigenous clastic,rich organic carbon and pyrite)to light gray and linen.The content of P2 O5 in ore bed increases ac-cordingly,and the change of CaO content is proportionate to that of P2 O5 content,and it suggests that hy-drodynamic condition becomes stronger,and it reflects that sedimentary environment turns into bay environ-ment dominated by tidal action.Hence,formation conditions of shallow-water carbonate dominance lithofa-cies in Doushantuo Formation is the prerequisite of phosphorus mineralization.Warm and dry palaeoclimate provides favorable conditions for precipitation and sediment of phosphorus,and suitable beach palaeogeo-graphic environment build the perfect locale for mineralization.The palaeotectonic condition of “uplift in middle Guizhou”is the most primary controlling factor in distribution of phosphorus deposits and formation of high-grade ores.%瓮福磷矿沉积的有利场所是潮下海湾浅滩环境,而不是潮坪。海湾的大小又控制着矿床的规模,海滩能量的差异影响着磷矿石的不同结构成因类型。矿石的结构,从凝胶-细砂屑与砂屑颗粒由细变粗;岩石的颜色由灰褐、黑色(多陆屑、富有机炭及黄铁矿)变为浅灰、灰白色;矿层中P2 O5含量随之渐增,而且CaO 含量变化与P2 O5含量变化同步,说明水动力条件由弱渐强,反映了沉积环境由潮汐作用为主的海湾环境。为此,陡山沱组以浅水碳酸盐优势岩相的地层条件是成磷的前提;温暖、干燥的古气候提供了有利于磷质的析出及沉积;

  4. Role of depositional environments in the preservation and detection of past tsunamis: lessons from 2004 Indian Ocean tsunami

    Science.gov (United States)

    Rajendran, Kusala; Chittenipattu, Rajendran; Andrade, Vanessa

    2013-04-01

    Reconstructing the tsunamigenic earthquake history of a region aids hazard assessment, and in the absence of written records, tsunami geology is the only tool to constrain the chronology and magnitudes of previous tsunamis to have affected a region. Observations along the Andaman-Nicobar Islands and the east coast of India suggest that distant and geomorphologically sheltered sites provide more conducive environments for tsunami deposition and preservation. The 2004 deposits from the Andaman Islands are mainly organic debris, sand sheets, coral debris and boulder deposits. The 2004 coseismic deformational features include uplift and subsidence of land as well as soil liquefaction. We use sites of tsunami deposits and deformational features to obtain evidence leading to past tsunamigenic earthquakes. The study spans latitudes from 7-14° N, from Campbell Bay to East Island. We classify the ages into three grades, A, B and C, based on the stratigraphic context of the deposit and the material and the age uncertainties. The earliest of the tsunamis occurred between 2nd and 6th centuries AD, evidenced by the coastal boulder beds of the southern Car Nicobar Island. A subsequent tsunami probably in the age range AD 770-1040 is inferred from both the Andaman and Nicobar Islands and on the Indian subcontinent. It is the strongest candidate for a 2004-caliber earthquake in the past 1500 years or more. The A&N Islands also contain tsunami deposits from AD 1250-1450 that probably matches those previously reported from Sumatra and Thailand. Evidence from what we consider as protected inland sites as well as coseismic deformation and liquefaction fall in the same age brackets as AD 1250-1450 from Indonesia, Thailand and AD 770-1040, from Indonesia, Sri Lanka and the east coast of India. By using deposits from the inland locations within the rupture as well as transoceanic sites, and other proxies dated in the same age bracket, we suggest that the ~1000 year old earthquake best

  5. Depositional environment and source rock potential of Cenomanian and Turonian sedimentary rocks of the Tarfaya Basin, Southwest Morocco

    Energy Technology Data Exchange (ETDEWEB)

    Ghassal, B.I.; Littke, R.; Sachse, V.; Sindern, S.; Schwarzbauer, J.

    2016-07-01

    Detailed organic and inorganic geochemical analyses were used to assess the depositional environment and source rock potential of the Cenomanian and Turonian oil shale deposits in the Tarfaya Basin. This study is based on core samples from the Tarfaya Sondage-4 well that penetrated over 300m of Mid Cretaceous organic matter-rich deposits. A total of 242 samples were analyzed for total organic and inorganic carbon and selected samples for total sulfur and major elements as well as for organic petrology, Rock-Eval pyrolysis, Curie-Point-pyrolysis-gaschromatography-Mass-Spectrometry and molecular geochemistry of solvent extracts. Based on major elements the lower Cenomanian differs from the other intervals by higher silicate and lower carbonate contents. Moreover, the molecular geochemistry suggests anoxic bottom marine water conditions during the Cenomanian-Turonian Boundary Event (CTBE; Oceanic Anoxic Event 2: OAE2). As a proxy for the Sorg/Corg ratio, the ratio total thiophenes/total benzenes compounds was calculated from pyrolysate compositions. The results suggest that Sorg/ Corg is low in the lower Cenomanian, moderate in the upper Cenomanian, very high in the CTBE (CenomanianTuronian Boundary Event) and high in the Turonian samples. Rock-Eval data reveal that the lower Cenomanian is a moderately organic carbon-rich source rock with good potential to generate oil and gas upon thermal maturation. On the other hand, the samples from the upper Cenomanian to Turonian exhibit higher organic carbon content and can be classified as oil-prone source rocks. Based on Tmax data, all rocks are thermally immature. The microscopic investigations suggest dominance of submicroscopic organic matter in all samples and different contents of bituminite and alginite. The lower Cenomanian samples have little visible organic matter and no bituminite. The upper Cenomanian and CTBE samples are poor in bituminite and have rare visible organic matter, whereas the Turonian samples change

  6. Correlation of cell surface proteins of distinct Beauveria bassiana cell types and adaption to varied environment and interaction with the host insect.

    Science.gov (United States)

    Yang, Zhi; Jiang, Hongyan; Zhao, Xin; Lu, Zhuoyue; Luo, Zhibing; Li, Xuebing; Zhao, Jing; Zhang, Yongjun

    2017-02-01

    The insect fungal pathogen Beauveria bassiana produces a number of distinct cell types that include aerial conidia, blastospores and haemolymph-derived cells, termed hyphal bodies, to adapt varied environment niches and within the host insect. These cells display distinct biochemical properties and surface structures, and a highly ordered outermost brush-like structure uniquely present on hyphal bodies, but not on any in vitro cells. Here, we found that the outermost structure on the hyphal bodies mainly consisted of proteins associated to structural wall components in that most of it could be removed by dithiothreitol (DTT) or proteinase K. DTT-treatment also caused delayed germination, decreased tolerance to ultraviolet irradiation and virulence of conidia or blastospores, with decreased adherence and alternated carbohydrate epitopes, suggesting involvement in fungal development, stress responses and virulence. To characterize these cell surface molecules, proteins were released from the living cells using DTT, and identified and quantitated using label-free quantitative mass spectrometry. Thereafter, a series of bioinformatics programs were used to predict cell surface-associated proteins (CSAPs), and 96, 166 and 54 CSAPs were predicted from the identified protein pools of conidia, blastospores and hyphal bodies, respectively, which were involved in utilization of carbohydrate, nitrogen, and lipid, detoxification, pathogen-host interaction, and likely other cellular processes. Thirteen, sixty-nine and six CSAPs were exclusive in conidia, blastospores and hyphal bodies, respectively, which were verified by eGFP-tagged proteins at their N-terminus. Our data provide a crucial cue to understand mechanism of B. bassiana to adapt to varied environment and interaction with insect host.

  7. Early Eocene volcanic ashes on Greifswalder Oie and their depositional environment, with an overview of coeval ash-bearing deposits in northern Germany and Denmark

    Science.gov (United States)

    Obst, Karsten; Ansorge, Jörg; Matting, Sabine; Hüneke, Heiko

    2015-11-01

    Unconsolidated bentonites and carbonate-cemented volcanic ashes occur in northern Germany within the clay sequence of the Lamstedt and Schlieven Formations documented by several wells. Ash-bearing carbonate concretions (so-called cementstones) are also known from glacially transported rafts and erratic boulders on the Baltic Sea island Greifswalder Oie, representing the easternmost exposures of early Eocene sediments in the North Sea Basin. The ashes can be correlated with water-lain ashes of the Danish Fur and Ølst Formations (mo-clay) generated during the opening of the North Atlantic Ocean about 55 Ma ago. Two types of cementstones can be distinguished on the basis of the mineralogical composition, sedimentary features and fossil content. Greifswalder Oie type I contains a black, up to 12-cm-thick ash deposit that follows above two distinct thin grey ash layers. The major ash unit has a rather homogeneous lower part; only a very weak normal grading and faint lamination are discernible. In the upper part, however, intercalations with light mudstone, in part intensively bioturbated, together with parallel and cross-lamination suggest reworking of the ash in a shallow marine environment. Major and trace element compositions are used to correlate type I ashes with those of the Danish-positive series which represent rather uniform ferrobasalts of the Danish stage 4, probably related to the emergence of proto-Iceland. In contrast, type II ash comprises a single, normally graded, about 5-cm-thick layer of water-lain air-fall tuff, which is embedded in fine-grained sandstone to muddy siltstone. Type II ash is characterised by very high TiO2 but low MgO contents. Exceptional REE patterns with a pronounced positive Eu anomaly suggest intense leaching of the glass that hampers exact correlation with pyroclastic deposits within the North Atlantic Igneous Province.

  8. A model for simulating the deposition of water-lain sediments in dryland environments

    Directory of Open Access Journals (Sweden)

    M. A. Bunch

    2004-01-01

    Full Text Available A numerical process-imitating model, the Discrete Storm Event Sedimentation Simulator (DSESS, has been developed to represent the climatic and hydraulic conditions of drylands in modelling their geomorphological development and sedimentary facies distributions. The ultimate aim is to provide insights into the lateral variability of permeability in the Triassic Sandstone aquifers of the UK for the study of solute movement. DSESS employs discrete storm-flood automata, released across a cellular landscape, to model sediment transport: erosion, migration and deposition. Sediment classes with different grain sizes can be modelled. Empirical process-based equations are used to quantify the movement of the automata, their erosion potential, sediment-carrying capacity and interaction with the underlying sediments. The approach emphasises the sequence of dryland storm events and associated floods rather than their timing. Flood events are assumed to be discrete in time. Preliminary tests carried out with DSESS using simple systems and idealised initial conditions produce lithological and land surface features characteristic of dryland settings and indicate the potential of the model for large-scale, long-time modelling of sedimentary facies development. Markedly different results are observed across the range of tests carried out in response to the non-linear interactions between the different elements of the landscape and the floodwaters simulated with DSESS. Simulations show that sediment accumulations develop concave upward radial profiles, plano-convex cross-profiles and possess a general lateral grading of sediment with distance from source. The internal grain size architecture shows evidence of both persistent and rapidly changing flow conditions, with both lateral and longitudinal stepping of coarse bodies produced by ‘scour and fill’ events and random avulsions. Armoured layers form so that near-surface sediments have increased likelihood of

  9. Experimental Studies of Spray Deposition on a Flat Surface in a Vacuum Environment

    Science.gov (United States)

    Golliher, Eric L.; Yao, S. C.

    2015-01-01

    Cooling of spacecraft components in the space environment is an on-going research effort. The electronics used in modern spacecraft are always changing and the heat flux is increasing. New, one-of-a-kind missions require new approaches to thermal control. In this research, under vacuum conditions, a pulsed water spray impinged on a small disc, while a high speed data acquisition system recorded the temperature histories of this copper disc. The water droplets froze quickly and accumulated on the disc as the spray continued. After the spray stopped, the frozen water that remained on the disc then sublimated into the vacuum environment and cooled the disc. This paper examines two important aspects of this process: 1) the difference in spray start up and shutdown in a vacuum environment versus in a standard atmospheric pressure environment, and 2) the water utilization efficiency in a vacuum environment due to the effects of drop trajectories and drop bouncing on the surface. Both phenomena play a role during spray cooling in a vacuum. This knowledge should help spacecraft designers plan for spray cooling as an option to cool spacecraft electronics, human metabolic generated heat, and heat from other sources.

  10. Organic nitrogen deposition on land and coastal environments: a review of methods and data

    Science.gov (United States)

    Cornell, S. E.; Jickells, T. D.; Cape, J. N.; Rowland, A. P.; Duce, R. A.

    Despite over a century of published reports of dissolved organic nitrogen (DON) in precipitation, its implications are still being appraised. The number of studies focusing on atmospheric organic nitrogen deposition has increased steadily in recent years, but comparatively little has been done to draw together this disparate knowledge. This is partly a consequence of valid concerns about the comparability of analysis and sampling methodologies. Given the current global trends in anthropogenic nitrogen fixation, an improved qualitative and quantitative understanding of the organic nitrogen component is needed to complement the well-established knowledge base pertaining to nitrate and ammonium deposition. This global review confirms the quantitative importance of bulk DON in precipitation. This cumulative data set also helps to resolve some of the uncertainty that arises from the generally locally and temporally limited scale of the individual studies. Because of analytical and procedural changes in recent decades, assessments are made of the comparability of the data sets; caution is needed in comparisons of individual studies, but the overall trends in the compiled set are more robust. Despite the large number of reports considered, evidence for long-term temporal changes in rainwater organic nitrogen concentrations is ambiguous. With regard to sources, it is likely that some of the organic material observed is not locally generated, but undergoes extensive or long-range atmospheric transport. The compiled data set shows a land-to-sea gradient in organic nitrogen concentration. Possible precursors, reported data on the most likely component groups, and potential source mechanisms are also outlined.

  11. Initial studies of Bremsstrahlung energy deposition in small-bore superconducting undulator structures in linac environments

    Energy Technology Data Exchange (ETDEWEB)

    Cremer, T.; Tatchyn, R. [Stanford Univ., CA (United States)

    1995-12-31

    One of the more promising technologies for developing minimal-length insertion devices for linac-driven, single-pass Free Electron Lasers (FELs) operating in the x-ray range is based on the use of superconducting (SC) materials. In recent FEL simulations, for example, a bifilar helical SC device with a 2 cm period and 1.8 T field was found to require a 30 m saturation length for operation at 1.5{Angstrom} on a 15 GeV linac, more than 40% shorter than an alternative hybrid/permanent magnet (hybrid/PM) undulator. AT the same time, however, SC technology is known to present characteristic difficulties for insertion device design, both in engineering detail and in operation. Perhaps the most critical problem, as observed, e.g., by Madey and co-workers in their initial FEL experiments, was the frequent quenching induced by scattered electrons upstream of their (bifilar) device. Postulating that this quenching was precipitated by directly-scattered or bremsstrahlung-induced particle energy deposited into the SC material or into material contiguous with it, the importance of numerical and experimental characterizations of this phenomenon for linac-based, user-facility SC undulator design becomes evident. In this paper we discuss selected prior experimental results and report on initial EGS4 code studies of scattered and bremsstrahlung induced particle energy deposition into SC structures with geometries comparable to a small-bore bifilar helical undulator.

  12. Insights from the metagenome of an acid salt lake: the role of biology in an extreme depositional environment.

    Science.gov (United States)

    Johnson, Sarah Stewart; Chevrette, Marc Gerard; Ehlmann, Bethany L; Benison, Kathleen Counter

    2015-01-01

    The extremely acidic brine lakes of the Yilgarn Craton of Western Australia are home to some of the most biologically challenging waters on Earth. In this study, we employed metagenomic shotgun sequencing to generate a microbial profile of the depositional environment associated with the sulfur-rich sediments of one such lake. Of the 1.5 M high-quality reads generated, 0.25 M were mapped to protein features, which in turn provide new insights into the metabolic function of this community. In particular, 45 diverse genes associated with sulfur metabolism were identified, the majority of which were linked to either the conversion of sulfate to adenylylsulfate and the subsequent production of sulfide from sulfite or the oxidation of sulfide, elemental sulfur, and thiosulfate via the sulfur oxidation (Sox) system. This is the first metagenomic study of an acidic, hypersaline depositional environment, and we present evidence for a surprisingly high level of microbial diversity. Our findings also illuminate the possibility that we may be meaningfully underestimating the effects of biology on the chemistry of these sulfur-rich sediments, thereby influencing our understanding of past geobiological conditions that may have been present on Earth as well as early Mars.

  13. Depositional Environments of the Upper Permian Quartzose Sandstone (Shandong Province, North China):Insight from Trace Element Geochemistry

    Institute of Scientific and Technical Information of China (English)

    Dawei L; Zengxue Li; Jitao Chen; Ying Liu; Zengqi Zhang; Jipo Liang; Haiyan Liu

    2015-01-01

    The depositional environment of the Upper Permian quartzose sandstone (Kuishan sand-stone in Shihezi Formation of Upper Permian) in the North China epicontinental basin is controversial. In order to test the previous hypotheses, we analyzed sedimentological characteristics of the Kuishan sandstones in outcrops and boreholes, and carried out trace element geochemical analysis by electron probe microanalyzer. Three lithofacies were recognized, including normal-graded conglomerate (Cng), trough and planar cross-bedded coarse sandstone (CStpc), and planar cross-bedded medium sandstone (MSpc). Normal-graded conglomerate (Cng) formed in the meandering river or deltaic distributary channels. Trough and planar cross-bedded coarse sandstone (CStpc) formed in meandering river or distributary channels of near-source deltaic plain. Planar cross-bedded medium sandstone (MSpc) formed in the siliciclastic beach with high-to moderate-energy conditions. By the petrology and trace elements analysis, three relatively large-scale transgressions were revealed. Each transgression was re-flected by the lower content of Ba and ratios of Fe/Mn, and the high content of B and ratios of B/Ga. The ratios of Ni/Co of all samples are all lower than 2, suggesting oxygen-enriched shallower water en-vironment during deposition of the Kuishan sandstones.

  14. Depositional environments of the south-eastern Volga-Ural anteclise in the Early-Middle Devonian.

    Science.gov (United States)

    Selezeneva, Natalia

    2017-04-01

    Nowadays, in the Orenburg region of Russia hydrocarbon potential has been determined down to a depth of 5 km. Therefore, discovery of deep fields is becoming a pressing issue there. Seismic profiles on the south-eastern part of Volga-Ural anteclise indicate two uplifts at the depth of 6-7 km composed of Emsian-Givetian deposits which likely represent large carbonate buildups. Then facies analysis of this territory (based on data of about 100 boreholes) was made and it confirmed the presence of bioherm massifs and showed sedimentary environments. Analysis of the composition and the structure of deposits revealed that in the Emsian stage a shallow-water shelf basin existed, which deepened toward the Ural and North Caspian basins and was characterized by the transgressive evolution. The early stage of transgression was dominated by the terrigenous sedimentation. This region likely had a prodelta with three (proximal, intermediate, and distal) zones. Then the basin was deepened, the amount of terrigenous material decreased and carbonate massifs started to form. At that time following environments occurred: shallow-water coastal zone, intrabasin uplift, shallow-water distal zone, relatively deep-water zone and riftogenic carbonate buildups. Facies analysis of Eifelian sediments showed that there were two shallow-water zones, where carbonates were deposed with formation of small separate organic structures, surrounded by relatively deep-water zone. Continued submergence caused development of bioherm massifs. Givetian deposits differed from the Eifelian by abundant input of the terrigenous material. The growth of the bioherm massifs stopped during this time. Due to facies analyses such paleogeographic zones as shallow-water coastal zone, deep-water shelf zone, submarine fan zone were defined. As a result, two buried reefs were discovered, which could be perspective for finding out oil and gas. These bioherms are covered by the Tournaisian depression sediments that could

  15. Bacterial communities in termite fungus combs are comprised of consistent gut deposits and contributions from the environment.

    Science.gov (United States)

    Otani, Saria; Hansen, Lars H; Sørensen, Søren J; Poulsen, Michael

    2016-01-01

    Fungus-growing termites (subfamily Macrotermitinae) mix plant forage with asexual spores of their plant-degrading fungal symbiont Termitomyces in their guts and deposit this blend in fungus comb structures, within which the plant matter is degraded. As Termitomyces grows, it produces nodules with asexual spores, which the termites feed on. Since all comb material passes through termite guts, it is inevitable that gut bacteria are also deposited in the comb, but it has remained unknown which bacteria are deposited and whether distinct comb bacterial communities are sustained. Using high-throughput sequencing of the 16S rRNA gene, we explored the bacterial community compositions of 33 fungus comb samples from four termite species (three genera) collected at four South African geographic locations in 2011 and 2013. We identified 33 bacterial phyla, with Firmicutes, Bacteroidetes, Proteobacteria, Actinobacteria, and Candidate division TM7 jointly accounting for 92 % of the reads. Analyses of gut microbiotas from 25 of the 33 colonies showed that dominant fungus comb taxa originate from the termite gut. While gut communities were consistent between 2011 and 2013, comb community compositions shifted over time. These shifts did not appear to be due to changes in the taxa present, but rather due to differences in the relative abundances of primarily gut-derived bacteria within fungus combs. This indicates that fungus comb microbiotas are largely termite species-specific due to major contributions from gut deposits and also that environment affects which gut bacteria dominate comb communities at a given point in time.

  16. Hydrogen isotope composition of natural gases from the Tarim Basin and its indication of depositional environments of the source rocks

    Institute of Scientific and Technical Information of China (English)

    LIU QuanYou; DAI JinXing; LI Jian; ZHOU QingHua

    2008-01-01

    By measuring carbon and hydrogen isotope compositions for C1, C2 and C3 of 74 gas samples, natural gases from the Tarim Basin can be divided into six groups on the basis of their origins: (1) coal-type gas derived from coal measures; (2) coal-type gas generated from the T-J lacustrine mudstones; (3) oil-type gas derived from the Cambrian and low Ordovician marine source rocks; (4) oil-type gas from the source rocks deposited in the marine -transitional facies; (5) mixing gas between gas derived from the Carboniferous transitional source rocks and the Mesozoic humic gas, and (6) mixing gases of of methane in natural gases originating from different type kerogens are affected by both palaeo-environments of the source rock formation (kerogen types) and thermal maturity, with sedimentary environment (kerogen type) as the main controlling factor. Under the similar thermal maturity, the hydrogen isotope composition of methane is more enriched in deuterium in marine environments than lacustrine one. With the increase of thermal maturity and the increase of carbon atomic numbers of environment of the source rock formation. The partial reversal of hydrogen isotopes for gaseous alkanes would be related to the microbial oxidation, mixing of sapropelic and humic gases and / or mixing of gases from similar kerogen sources with various thermal maturities. In the oil-type gas, the sul

  17. Assessing Reservoir Depositional Environments to Develop and Quantify Improvements in CO2 Storage Efficiency. A Reservoir Simulation Approach

    Energy Technology Data Exchange (ETDEWEB)

    Okwen, Roland [University of Illinois, Champaign, IL (United States); Frailey, Scott [University of Illinois, Champaign, IL (United States); Leetaru, Hannes [University of Illinois, Champaign, IL (United States); Moulton, Sandy [Illinois State Geological Survey, Champaign, IL (United States)

    2014-09-30

    The storage potential and fluid movement within formations are dependent on the unique hydraulic characteristics of their respective depositional environments. Storage efficiency (E) quantifies the potential for storage in a geologic depositional environment and is used to assess basinal or regional CO2 storage resources. Current estimates of storage resources are calculated using common E ranges by lithology and not by depositional environment. The objectives of this project are to quantify E ranges and identify E enhancement strategies for different depositional environments via reservoir simulation studies. The depositional environments considered include deltaic, shelf clastic, shelf carbonate, fluvial deltaic, strandplain, reef, fluvial and alluvial, and turbidite. Strategies considered for enhancing E include CO2 injection via vertical, horizontal, and deviated wells, selective completions, water production, and multi-well injection. Conceptual geologic and geocellular models of the depositional environments were developed based on data from Illinois Basin oil fields and gas storage sites. The geologic and geocellular models were generalized for use in other US sedimentary basins. An important aspect of this work is the development of conceptual geologic and geocellular models that reflect the uniqueness of each depositional environment. Different injection well completions methods were simulated to investigate methods of enhancing E in the presence of geologic heterogeneity specific to a depositional environment. Modeling scenarios included horizontal wells (length, orientation, and inclination), selective and dynamic completions, water production, and multiwell injection. A Geologic Storage Efficiency Calculator (GSECalc) was developed to calculate E from reservoir simulation output. Estimated E values were normalized to diminish their dependency on fluid relative permeability. Classifying depositional environments according to

  18. Early Archaean sedimentary basins: depositional environment and hydrothermal systems. Geologica Ultraiectina (244)

    NARCIS (Netherlands)

    de Vries, S.T.|info:eu-repo/dai/nl/33656791X

    2004-01-01

    The topic of this thesis is the Early Archaean environment and hydrothermal systems in the Barberton Greenstone Belt (BGB) in South Africa, and the Coppin Gap Greenstone Belt (CGGB) in the Pilbara, Australia. Focus within these greenstone belts is on the ~3.45-3.42 Ga Buck Ridge volcano-sedimentary

  19. Quantification of Gaseous Elemental Mercury Dry Deposition to Environmental Surfaces using Mercury Stable Isotopes in a Controlled Environment

    Science.gov (United States)

    Rutter, A. P.; Schauer, J. J.; Shafer, M. M.; Olson, M.; Robinson, M.; Vanderveer, P.; Creswell, J. E.; Parman, A.; Mallek, J.; Gorski, P.

    2009-12-01

    Andrew P. Rutter (1) * *, James J, Schauer (1,2) *, Martin M. Shafer(1,2), Michael R. Olson (1), Michael Robinson (1), Peter Vanderveer (3), Joel Creswell (1), Justin L. Mallek (1), Andrew M. Parman (1) (1) Environmental Chemistry and Technology Program, 660 N. Park St, Madison, WI 53705. (2) Wisconsin State Laboratory of Hygiene, 2601 Agriculture Drive, Madison, WI 53718. (3) Biotron, University of Wisconsin - Madison, 2115 Observatory Drive, Madison, WI 53706 * Correspond author(jjschauer@wisc.edu) * *Presenting author (aprutter@wisc.edu) Abstract Gaseous elemental mercury (GEM) is the predominant component of atmospheric mercury outside of arctic depletion events, and locations where anthropogenic point sources are not influencing atmospheric concentrations. GEM constitutes greater than 99% of the mercury mass in most rural and remote locations. While dry and wet deposition of atmospheric mercury is thought to be dominated by oxidized mercury (a.k.a. reactive mercury), only small GEM uptake to environmental surfaces could impact the input of mercury to terrestrial and aquatic ecosystems. Dry deposition and subsequent re-emission of gaseous elemental mercury is a pathway from the atmosphere that remains only partially understood from a mechanistic perspective. In order to properly model GEM dry deposition and re-emission an understanding of its dependence on irradiance, temperature, and relative humidity must be measured and parameterized for a broad spectrum of environmental surfaces colocated with surrogate deposition surfaces used to make field based dry deposition measurements. Measurements of isotopically enriched GEM dry deposition were made with a variety of environmental surfaces in a controlled environment room at the University of Wisconsin Biotron. The experimental set up allowed dry deposition components which are not easily separated in the field to be decoupled. We were able to isolate surface transfer processes from variabilities caused by

  20. Protection of Polymers from the Space Environment by Atomic Layer Deposition

    Science.gov (United States)

    Lindholm, Ned F.; Zhang, Jianming; Minton, Timothy K.; O'Patchen, Jennifer; George, Steven M.; Groner, Markus D.

    2009-01-01

    Polymers in space may be subjected to a barrage of incident atoms, photons, and/or ions. For example, oxygen atoms can etch and oxidize these materials. Photons may act either alone or in combination with oxygen atoms to degrade polymers and paints and thus limit their usefulness. Colors fade under the intense vacuum ultraviolet (VUV) solar radiation. Ions can lead to the build-up of static charge on polymers. Atomic layer deposition (ALD) techniques can provide coatings that could mitigate many challenges for polymers in space. ALD is a gas-phase technique based on two sequential, self-limiting surface reactions, and it can deposit very uniform, conformal, and pinhole-free films with atomic layer control. We have studied the efficacy of various ALD coatings to protect Kapton® polyimide, FEP Teflon®, and poly(methyl methacrylate) films from atomic-oxygen and VUV attack. Atomic-oxygen and VUV studies were conducted with the use of a laser-breakdown source for hyperthermal O atoms and a D2 lamp as a source of VUV light. These studies used a quartz crystal microbalance (QCM) to monitor mass loss in situ, as well as surface profilometry and scanning electron microscopy to study the surface recession and morphology changes ex situ. Al2O3 ALD coatings applied to polyimide and FEP Teflon® films protected the underlying substrates from O-atom attack, and ZnO coatings protected the poly(methyl methacrylate) substrate from VUV-induced damage.

  1. A model for simulating the deposition of water-lain sediments in dryland environments

    Science.gov (United States)

    Bunch, M. A.; Mackay, R.; Tellam, J. H.; Turner, P.

    A numerical process-imitating model, the Discrete Storm Event Sedimentation Simulator (DSESS), has been developed to represent the climatic and hydraulic conditions of drylands in modelling their geomorphological development and sedimentary facies distributions. The ultimate aim is to provide insights into the lateral variability of permeability in the Triassic Sandstone aquifers of the UK for the study of solute movement. DSESS employs discrete storm-flood automata, released across a cellular landscape, to model sediment transport: erosion, migration and deposition. Sediment classes with different grain sizes can be modelled. Empirical process-based equations are used to quantify the movement of the automata, their erosion potential, sediment-carrying capacity and interaction with the underlying sediments. The approach emphasises the sequence of dryland storm events and associated floods rather than their timing. Flood events are assumed to be discrete in time. Preliminary tests carried out with DSESS using simple systems and idealised initial conditions produce lithological and land surface features characteristic of dryland settings and indicate the potential of the model for large-scale, long-time modelling of sedimentary facies development. Markedly different results are observed across the range of tests carried out in response to the non-linear interactions between the different elements of the landscape and the floodwaters simulated with DSESS. Simulations show that sediment accumulations develop concave upward radial profiles, plano-convex cross-profiles and possess a general lateral grading of sediment with distance from source. The internal grain size architecture shows evidence of both persistent and rapidly changing flow conditions, with both lateral and longitudinal stepping of coarse bodies produced by ‘scour and fill’ events and random avulsions. Armoured layers form so that near-surface sediments have increased likelihood of preservation

  2. Poultry litter and the environment: Physiochemical properties of litter and soil during successive flock rotations and after remote site deposition.

    Science.gov (United States)

    Crippen, Tawni L; Sheffield, Cynthia L; Byrd, J Allen; Esquivel, Jesus F; Beier, Ross C; Yeater, Kathleen

    2016-05-15

    The U.S. broiler meat market has grown over the past 16 years and destinations for U.S. broiler meat exports expanded to over 150 countries. This market opportunity has spurred a corresponding increase in industrialized poultry production, which due to the confined space in which high numbers of animals are housed, risks accumulating nutrients and pollutants. The purpose of this research was to determine the level of pollutants within poultry litter and the underlying soil within a production facility; and to explore the impact of spent litter deposition into the environment. The study follows a production facility for the first 2.5 years of production. It monitors the effects of successive flocks and management practices on 15 physiochemical parameters: Ca, Cu, electrical conductivity, Fe, K, Mg, Mn, moisture, Na, NO3(-)/N, organic matter, P, pH, S, and Zn. Litter samples were collected in-house, after clean-outs and during stockpiling. The soil before house placement, after the clean-outs and following litter stockpiling was monitored. Management practices markedly altered the physiochemical profiles of the litter in-house. A canonical discriminant analysis was used to describe the relationship between the parameters and sampling times. The litter profiles grouped into five clusters corresponding to time and management practices. The soil in-house exhibited mean increases in all physiochemical parameters (2-297 fold) except Fe, Mg, %M, and pH. The spent litter was followed after deposition onto a field for use as fertilizer. After 20 weeks, the soil beneath the litter exhibited increases in EC, Cu, K, Na, NO3(-)/N, %OM, P, S and Zn; while %M decreased. Understanding the impacts of industrialized poultry farms on the environment is vital as the cumulative ecological impact of this land usage could be substantial if not properly managed to reduce the risk of potential pollutant infiltration into the environment.

  3. Depositional environment and source potential of Jurassic coal-bearing sediments (Gresten Formation, Hoflein gas/condensate field, Austria)

    Energy Technology Data Exchange (ETDEWEB)

    Sachsenhofer, R.F.; Bechtel, A.; Kuffner, T.; Rainer, T.; Gratzer, R.; Sauer, R.; Sperl, H. [Mount University of Leoben, Leoben (Austria)

    2006-05-15

    Coal-bearing Jurassic sediments (Gresten Formation; Lower Quartzarenite Member) are discussed as source rocks for gas and minor oil in the basement of the Alpine-Carpathian frontal zone (e.g. Hoflein gas/condensate field). Core material has therefore been analysed to characterize depositional environment and source potential of the Lower Quartzarenite Member (LQM). Geochemical data from the Hoflein condensate are used to establish a Source-condensate correlation. The LQM was deposited in a flood basin with transitions to a delta-plain environment. Coal originated in frequently flooded mires and evolved within an oxygenated and acidic environment. It is inferred from geochemical data that organic matter from aquatic macrophytes and gymnosperms contributed to coal formation. Wildfires were abundant and oxidation of plant remains occurred frequently. This resulted in the formation of dull coal with very high inertinite contents. Bituminous shales were formed in deeper waters under dysoxic conditions. Apart from abundant algae and micro-organisms, it is concluded that there was an increased contribution of higher land plants relative to macrophytes to the biomass of the shales. Despite high inertinite contents, coal within the LQM has a significant oil potential. Bituminous shales contain a Type III-II kerogen. According to pyrolysis-gas chromatography data, coal and shale generate a high wax paraffinic oil. The organic matter is immature to marginal mature (0.55% Rr). Bituminous shales are considered a potential source for the Hoflein condensate. Coal may be the source for gas and minor oil in the Klement Field, but is not the source for the condensate.

  4. Varying the morphology of silver nanoparticles results in differential toxicity against micro-organisms, HaCaT keratinocytes and affects skin deposition.

    Science.gov (United States)

    Holmes, Amy M; Lim, Julian; Studier, Hauke; Roberts, Michael S

    2016-12-01

    The use of silver nanoparticles (Ag NPs) within the healthcare sector and consumer products is rapidly increasing. There are now a range of diverse-shaped Ag NPs that are commercially available and many of the products containing nanosilver are topically applied to human skin. Currently, there is limited data on the extent to which the antimicrobial efficacy and cytotoxicity of Ag NPs is related to their shape and how the shape of the Ag NPs affects their distribution in both intact and burn wounded human skin after topical application. In this study, we related the relative Ag NP cytotoxicity to potential skin pathogens and HaCaT keratinocytes in vitro with the shape of the Ag NPs. We employed multiphoton fluorescence lifetime imaging to map the distribution of the native and unlabeled Ag NPs after topical application to both intact and burn wounded human skin using the localized surface plasmon resonance signal of the Ag NPs. Truncated plate shaped Ag NPs led to the highest cytotoxicity against both bacteria (IC50 ranges from 31.25 to 125 μg/mL depending on the bacterial species) and HaCaT keratinocytes (IC50 78.65 μg/mL [95%CI 63.88, 96.83]) thus both with similar orders of magnitude. All Ag NPs were less cytotoxic than solutions of silver nitrate (IC50 of 7.85 μg/mL [95%CI 1.49, 14.69]). Plate-shaped Ag NPs displayed the highest substantivity within the superficial layers of the stratum corneum when topically applied to intact skin and the highest deposition into the wound bed when applied to burned ex vivo human skin relative to other Ag NP shapes.

  5. Holocene depositional environments and surface-level changes at Lake Fryxell, Antarctica

    Science.gov (United States)

    Whittaker, T.E.; Hall, B.L.; Hendy, C.H.; Spaulding, S.A.

    2008-01-01

    We report on Holocene surface-level variations of Lake Fryxell, Antarctica, as determined from multi-proxy analyses of 18 sediment cores. During this time accumulating sediments were predominantly aeolian sand with algal and carbonate laminae. Based on stratigraphy, mineralogy and diatom assemblages we suggest some carbonate laminae were deposited when lake level dropped, leading to concentration and subsequent precipitation of salts. Although lake level appears to have remained relatively stable throughout the Holocene, minor (<4.5 m below present) lowstands occurred at approximately 6400, 4700, 3800 and ??? 1600 cal. yr BP. The stability of Lake Fryxell during the Holocene contrasts with large-scale variability at other Dry Valleys lakes (eg, Lake Vanda) and with suggestions from chemical diffusion models of a near-desiccation at ???1200 cal. yr BP. The reason for the comparative stability of Lake Fryxell is uncertain, but may be the result of basin morphology and the number, aspect and proximity of meltwater sources. ?? 2008 SAGE Publications.

  6. Upper Pennsylvanian coals and associated rocks - depositional environments, sedimentation, paleontology and paleobotany, upper Ohio River valley

    Energy Technology Data Exchange (ETDEWEB)

    Cross, A.T.

    1988-03-01

    A number of geologically interesting sites in the upper Ohio River valley will be visited during the North-Central Section of the Geological Society of America's meeting in Akron, OH in April 1988. Sixteen scheduled sites (and three substitutes) have been chosen. They represent the following features: field examples of various types of stratigraphic problems; sedimentologic characteristics of diverse environments; controlling structural or physiographic anomalies of pre-coal-forming peat accumulation surfaces; typical or unusual faunas and floras of terrestrial, brackish or marine origin; and various economic coals demonstrating geologic problems related to their origin, constitution and extraction.

  7. Isotopic characterization of cave environments at varying altitudes on the eastern Adriatic coast (Croatia) - Implications for future speleothem-based studies

    Science.gov (United States)

    Surić, Maša; Lončarić, Robert; Lončar, Nina; Buzjak, Nenad; Bajo, Petra; Drysdale, Russell N.

    2017-02-01

    An important step in the implementation of paleoclimate reconstructions from speleothems (cave carbonate deposits) is to evaluate the sensitivity of the host cave environment to regional climate. Accordingly, we studied three caves at different altitudes (74 m, 570 m and 1250 m a.s.l.) along a transect from the Dalmatian islands to Velebit Mountain peaks in coastal Croatia to characterize their environments in terms of each cave's suitability to host speleothems that would be capable of yielding robust paleoclimate reconstructions. We conducted cave microclimate (2-years) and dripwater (1-year) monitoring and analysed the isotopic composition of precipitation, cave dripwater and modern spelean calcite. As for the water isotopic imprints, the isotopic values of meteoric waters reaching the two lower-altitude caves, in spite of an altitude difference of 500 m, lie on local meteoric water lines (LMWLs) of similar slope and intercept (δ2H = 6.61 × δ18O + 4.92 and δ2H = 6.69 × δ18O + 6.86). Their slopes lower than that of GMWL indicate enhanced evaporation during the warm season. As expected, the LMWL of the highest cave region (δ2H = 7.83 × δ18O + 14.45) resembles the slope of the GMWL, but the values of deuterium excess obtained for all three caves (between 15.2‰ and 16.6‰) match that of western Mediterranean-sourced waters (∼15‰). Monthly d-excess values suggest Atlantic-sourced air masses can reach the sites throughout the year but never dominate the rainfall composition. The altitude effect was noted both in precipitation and in dripwater isotopic composition, but with notably different Δδ18O/100 m gradients (-0.33‰ and -0.11‰, respectively). Stable isotope variations of the dripwaters in all caves were attenuated in relation to the rainwater, even those of the drip sites with fracture-flow behaviour. Based on stable cave microclimate conditions, relatively steady discharges, and modern calcite apparently precipitated at or close to isotopic

  8. Fluvial depositional environment evolving into deltaic setting with marine influences in the buntsandstein of northern vosges (France)

    Science.gov (United States)

    Gall, Jean-Claude

    The Buntsandstein in the Northern Vosges (France) originates mainly in an inland braidplain fluvial environment which passes in the upper part of the sequence into deltaic milieu in the coastal plain along the border of the sea, with the continental environment finally being drowned with the transgression of the shallow sea. The fluvial sedimentation is characterized by the presence of two facies throughout the Buntsandstein : channel facies and overbank plain facies. The channel facies comprises sandy and conglomeratic deposits forming within active streams by strong currents, whereas the overbank plain facies is built up of silty-clayey sandstones or silt/clay originating in stagnant water in abandoned watercourses, ponds, pools and puddles. The significance of particularly the floodplain sediments is subjected to considerable changes throughout the Buntsandstein sequence. There are all stages of transition between overbank plain deposits being only preserved in ghost-like facies as reworked clasts due to effective secondary removal of primarily occasionally formed suspension fines, and an abundance of autochthonous floodplain sediments in the depositional record resulting from favourable conditions of primary origin and secondary preservation. Reworked ventifacts within fluvial channel sediments testify to subordinate aeolian influences in the alluvial plain, with reasonable reworking, however, having removed all in situ traces of wind activity. Declining aridity of palaeoclimate towards the top is indicated by the appearance of violet horizon palaeosols in the Zone-Limite-Violette and the Couches intermédiaires being accompanied by Bröckelbank carbonate breccias originating from concentration of reworked fragments of pedogenic carbonate nodules. Biogenic traces are in the lower part of the sequence mainly present as Planolites burrows in the finer-grained sediments. Palaeosalinities as revealed from boron contents indicate progressively increasing

  9. Release, deposition and elimination of radiocesium ((137)Cs) in the terrestrial environment.

    Science.gov (United States)

    Ashraf, Muhammad Aqeel; Khan, Ayesha Masood; Ahmad, Mushtaq; Akib, Shatirah; Balkhair, Khaled S; Bakar, Nor Kartini Abu

    2014-12-01

    Radionuclide contamination in terrestrial ecosystems has reached a dangerous level. The major artificial radionuclide present in the environment is (137)Cs, which is released as a result of weapon production related to atomic projects, accidental explosions of nuclear power plants and other sources, such as reactors, evaporation ponds, liquid storage tanks, and burial grounds. The release of potentially hazardous radionuclides (radiocesium) in recent years has provided the opportunity to conduct multidisciplinary studies on their fate and transport. Radiocesium's high fission yield and ease of detection made it a prime candidate for early radio-ecological investigations. The facility setting provides a diverse background for the improved understanding of various factors that contribute toward the fate and transfer of radionuclides in the terrestrial ecosystem. In this review, we summarize the significant environmental radiocesium transfer factors to determine the damaging effects of radiocesium on terrestrial ecosystem. It has been found that (137)Cs can trace the transport of other radionuclides that have a high affinity for binding to soil particles (silts and clays). Possible remedial methods are also discussed for contaminated terrestrial systems. This review will serve as a guideline for future studies of the fate and transport of (137)Cs in terrestrial environments in the wake of the Fukushima Nuclear Power Plant disaster in 2011.

  10. The variogram and the simple kriging estimator: Useful tools to complement lithologic correlation in a complex fluvial depositional environment

    Energy Technology Data Exchange (ETDEWEB)

    Murphy, J. [IT Corp., Martinez, CA (United States)

    1995-12-31

    Three dimensional grid estimation has been combined with an interpretive model of fluvial deposition for correlating low permeability zones in the shallow subsurface. Improvement in correlation reliability was realized by combining hand drawn interpretive cross-sections (spotting local trends in grain size, CPT log signature, etc.) with cross-section maps of the geostatistical grid model. The site is a military installation where soil contamination is being mapped and quantified using three dimensional modeling techniques. The subsurface is a complex fluvial depositional environment with intermittent bedrock highs and more frequent calcite and Calcium/Iron related cementation. Hence, the problem of lithologic correlation occurred where the drillhole spacing became wider than the channel belt width or cemented materials prevented detailed sampling. The goals of the sampling and analysis plan called for sampling within the first continuous silt or clay unit in order to quantify the zone of greatest contaminant retention on its downward migratory path. This paper will describe a three dimensional correlation technique which employs geostatistical analysis of CPT hole data specifically coded by permeability indicator thresholds. The process yielded variogram ranges applied to a simple kriging estimator on a 3-dimensional grid block. Estimates of clay probability are then provided as output and overlaid with the geologists cross section interpretation. The marriage of these two tools was invaluable in that geostatistical estimates sometimes behaved contrary to the channel depositional process, while on the other hand, the geologists interpretation often failed to recognize data in the third dimension (i.e. off section CPT data).

  11. Standard Practice for Selecting, Preparing, Exposing, and Analyzing Witness Surfaces for Measuring Particle Deposition in Cleanrooms and Associated Controlled Environments

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2006-01-01

    1.1 This practice is intended to assist in the selection, preparation, exposure, and analysis of witness surfaces for the purpose of characterizing particle deposition rates in cleanrooms and associated controlled environments, particularly for aerospace applications. 1.2 Requirements may be defined in terms of particle size distribution and count, percent area coverage, or product performance criteria such as optical transmission or scatter. Several choices for witness surfaces are provided. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 1.3 The values stated in SI units are to be regarded as the standard.

  12. Pollutant deposition via dew in urban and rural environment, Cracow, Poland

    Science.gov (United States)

    Muskała, Piotr; Sobik, Mieczysław; Błaś, Marek; Polkowska, Żaneta; Bokwa, Anita

    2015-01-01

    This study is a comparative analysis of dew in rural and urban environment. Dew samples were collected between May and October, 2009 in two reference stations in southern Poland: Cracow and Gaik-Brzezowa. The investigation included comparison of volume and chemistry of the collected samples. Due to its formation mechanisms, dew is a good indicator of air pollution. Following parameters were analyzed in 159 collected samples: pH, electric conductivity, concentration of formaldehyde and phenols, concentration of NH4+, Ca2 +, K+, Na+, and Mg2 + cations and NO2-, NO3-, SO42 -, Cl-, F-, and PO43 - anions. The frequency of dew was approximately the same, both in urban and rural conditions reaching 43% of the measurement period. Dew intensity, expressed by volume, was on average two times larger in rural environment than in urban conditions. Urban landuse was recognized as the main factor reducing dew intensity in the urban station in comparison to the rural. Furthermore, the intensity of dew depended on synoptic scale air circulation at both measurement sites. As expected, samples collected in Cracow were much more polluted than the ones from Gaik-Brzezowa. The average TIC (Total Ionic Content) parameter was approximately 50% higher at the urban station. The pH in the rural station was more acidic. NO3- anions and Ca2 + cations were predominant in both measurement sites, however the participation of Ca2 + in Cracow was higher. NO3- indicates pollutions emitted by transport and industrial sources. The concentration of the analytes in both stations, as the volume, depended on air circulation direction. For Gaik-Brzezowa the highest TIC was observed mainly within southern circulation, while for Cracow the highest TIC was noted within both northern and southern. In general the rural station represented background pollution for the whole region and the pollution in Cracow was more dependent on local urban sources as transport or industry.

  13. Stable Carbon Isotopic Compositions of Methylated-MTTC in Crude Oils from Saline Lacustrine Depositional Environment: Source Implications

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Significantly high abundant methyl-MethylTrimethylTridecylChromans (MTTCs) have been detected in aromatic hydrocarbon fractions in crude oils from the Jizhong Depression and Jianghan Basin. The distribution of these compounds is dominated by methyl-MTTC and dimethylMTTC series, which indicate diagenetic products of a hypersaline depositional environment in the early stage and show a low degree of methylation. The occurrence of significantly high abundant methyl-MTTC depends mainly on good preservation conditions with a strongly reductive, hypersaline and water-columned depositional environment and subsequent non-intensive diagenetic transformations. The stable carbon isotopic compositions of the methyl-MTTCs and dimethyl-MTTCs in two samples are far different from the stable carbon isotopic composition of C30 hopane of apparent bacteria biogenesis (up to 4.11‰ and 5.75‰, respectively). This obviously demonstrates that the methyl-MTTC and dimethyl-MTTCs cannot be of bacteria origin, which is different from the previous point of view about non-photosynthetic bacteria products or possible bacteria-reworked products. On the contrary, the stable carbon isotopic compositions of methyi-MTTC and dimethyl-MTTCs in the two samples were similar to that of the samecarbon-numbered n-alkanes (nC27-nC28-nC29), which indicates that they share the same source origin. Especially in the crude oil from the Zhao61 well, stable carbon isotopic compositions are also similar to that of the same carbon-numbered steranes with ααα-20R isomer (mostly less than 0.4‰). In consideration of the results of previous studies on saline lake ecological sedimentation, the authors hold that the methyl-MTTC and dimethyl-MTTCs in the saline lake sediments should be of algal biogenesis origin.

  14. Hydrogen isotope composition of natural gases from the Tarim Basin and its indication of depositional environments of the source rocks

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    By measuring carbon and hydrogen isotope compositions for C1, C2 and C3 of 74 gas samples, natural gases from the Tarim Basin can be divided into six groups on the basis of their origins: (1) coal-type gas derived from coal measures; (2) coal-type gas generated from the T-J lacustrine mudstones; (3) oil-type gas derived from the Cambrian and low Ordovician marine source rocks; (4) oil-type gas from the source rocks deposited in the marine-transitional facies; (5) mixing gas between gas derived from the Carboniferous transitional source rocks and the Mesozoic humic gas, and (6) mixing gases of thermal genetic gas and little deep gas in the Southwest depression of the Tarim Basin. The δ D values of methane in natural gases originating from different type kerogens are affected by both palaeo-environments of the source rock formation (kerogen types) and thermal maturity, with sedimentary environment (kerogen type) as the main controlling factor. Under the similar thermal maturity, the hydrogen isotope composition of methane is more enriched in deuterium in marine environments than lacustrine one. With the increase of thermal maturity and the increase of carbon atomic numbers of gaseous alkanes, the hydrogen isotopes become enriched in deuterium. The δ D values of ethane and propane (δ D2, δ D3) are controlled mainly by thermal maturity and to a lesser degree by sedimentary environment of the source rock formation. The partial reversal of hydrogen isotopes for gaseous alkanes would be related to the microbial oxidation, mixing of sapropelic and humic gases and / or mixing of gases from similar kerogen sources with various thermal maturities. In the oil-type gas, the sulfate reduction reaction would result in the reversed order of δ D1 and δ D2 (e.g. δ D1>δ D2).

  15. Late Holocene swampy forest of Loango Bay (Congo). Sedimentary environments and organic matter deposition

    Science.gov (United States)

    Malounguila-Nganga, Dieudonné; Giresse, Pierre; Boussafir, Mohammed; Miyouna, Timothée

    2017-10-01

    This region, comprised between the Kouilou estuary and Pointe-Noire, is characterised by a very specific morphological setting. On the continental side, the coastal sector is dominated by cliffs of sand over 100 m high, referred to as the Série des Cirques, whereas, on the ocean side, very active erosion is presently taking place which has resulted in a retreat of the shoreline of more than 100 m over the last hundred years. New 14C datings and different analyses of organic matter and clay minerals (X-Ray data) were performed in order to reconstruct the geological and ecological evolution of the area during the Late Holocene and replace it in the palaeoclimatic scheme deduced from previous regional studies. From 7 to 6000 yr cal BP, the accumulation of important beach barriers by the oceanic drift allowed the definition of a narrow swamp depression several tens of kilometres long. A dense ombrophile and hydromorphic forest, in spite of being very close to the oceanic coast, remained sheltered from any brackish influence and fed accumulations of peat and organic muds. The emersive trend of 3000-2000 yr BP, i.e. the passage from a vast forest swamp with a water body several metres deep to a wet zone with some emersions, is expressed by a large colluvial accumulation. High primary production is not clearly attested in this wet area. High HI values would indicate rather long-lasting conservation in a swampy environment, the lowest values indicating alternating episodes of emersion and immersion. In such peatlands, OM preservation is favoured by an anoxic environment and rapid burial. The δ 13C values of older peats dated ca. 7000 yr cal BP are -28 to -26‰, typical of a C3 origin. Thus, the ca. -16‰ value indicates the greatest opening of the cover, suggesting a forest-savanna mosaic ca. 2500 yr cal BP. At Kivesso, several proxies suggest a wetter trend towards 500 yr cal BP. An ultimate drier trend is observed during the last two centuries, which has been

  16. Varying Constants

    CERN Document Server

    Damour, Thibault Marie Alban Guillaume

    2003-01-01

    We review some string-inspired theoretical models which incorporate a correlated spacetime variation of coupling constants while remaining naturally compatible both with phenomenological constraints coming from geochemical data (Oklo; Rhenium decay) and with present equivalence principle tests. Barring unnatural fine-tunings of parameters, a variation of the fine-structure constant as large as that recently ``observed'' by Webb et al. in quasar absorption spectra appears to be incompatible with these phenomenological constraints. Independently of any model, it is emphasized that the best experimental probe of varying constants are high-precision tests of the universality of free fall, such as MICROSCOPE and STEP. Recent claims by Bekenstein that fine-structure-constant variability does not imply detectable violations of the equivalence principle are shown to be untenable.

  17. Facies analysis and depositional environments of the OligoceneeMiocene Asmari Formation, Zagros Basin, Iran

    Institute of Scientific and Technical Information of China (English)

    Mohammad Sahraeyan; Mohammad Bahrami; Solmaz Arzaghi

    2014-01-01

    The Asmari Formation (a giant hydrocarbon reservoir) is a thick carbonate sequence of the Oligocenee Miocene in the Zagros Basin, southwest of Iran. This formation is exposed at Tang-e-Lendeh in the Fars interior zone with a thickness of 190 m comprising medium and thick to massive bedded carbonates. The age of the Asmari Formation in the study area is the late Oligocene (Chattian)eearly Miocene (Burdigalian). Ten microfacies are defined, characterizing a gradual shallowing upward trend;the related environments are as follows:open marine (MF 8e10), restricted lagoon (MF 6e7), shoal (MF 3e5), lagoon (MF 2), and tidal flat (MF 1). Based on the environmental interpretations, a homoclinal ramp consisting of inner and middle parts prevails. MF 3e7 are characterized by the occurrence of large and small porcelaneous benthic foraminifera representing a shallow-water setting of an inner ramp, influenced by wave and tidal pro-cesses. MF 8e10, with large particles of coral and algae, represent a deeper fair weather wave base of a middle ramp setting.

  18. Mobilisation and Bioavailability of Arsenic Around Mesothermal Gold Deposits in a Semiarid Environment, Otago, New Zealand

    Directory of Open Access Journals (Sweden)

    D. Craw

    2002-01-01

    Full Text Available Arsenopyrite (FeAsS is the principal arsenic (As mineral in mineralised mesothermal veins (typically 5,000 mg/kg As in southeastern New Zealand. Groundwater in contact with arsenopyrite-bearing rocks has elevated As concentrations (up to 0.1 mg/l. The arsenopyrite decomposes slowly on oxidation in soils and historic mine workings in a cool semiarid climate. Dissolved As is predominantly As(III in association with arsenopyrite, but this is rapidly oxidised over days to weeks to As(V in the vadose zone. Oxidation is facilitated by particulate Fe and/or Mn oxyhydroxides, and by bacteria in surface waters. Evaporative concentration of dissolved As(V in the vadose zone causes precipitation of scorodite (Fe(IIIAs(VO4.2H2O. Adsorption of As(V to Fe oxyhydroxides in soils and groundwater pathways lowers dissolved As concentrations. Soils over mineralised veins typically have <200 mg/kg As, as most As is removed in solution on geological time scales. Most plants on the mineralised rocks and soils do not take up As, although some inedible species can fix up to 18 mg/kg As. Hence, bioavailability of As(V is low in this environment, despite the substantial As flux.

  19. Carbonate production and deposition in a warm-temperate macroalgal environment, Investigator Strait, South Australia

    Science.gov (United States)

    James, Noel P.; Bone, Yvonne

    2011-08-01

    The prolific macroalgal forests in shallow (red algae that are grazed by herbivorous gastropods, 2) an intermediate, 5-20 cm-high community of fleshy red algae, and 3) a 20-100 cm+-high canopy of large phaeophytes (especially Ecklonia, Cystophora and Xiophora) whose blades are locally encrusted with bryozoans, such as Membranipora membranacea, and spirorbids. Concealed surfaces of subvertical rock walls and cryptic habitats behind the macroalgal curtain have two tiers; 1) a cornucopia of encrusting plants and animals, especially crustose and geniculate corallines in shallow water, that give way in water depths > 4 m to numerous bryozoans (especially fenestrates), serpulid worms, numerous and diverse demosponges, ascidians, small solitary corals, epifaunal echinoids, and gastropods, and 2) a veil of macroalgae (mainly Cystophora and Ecklonia) that drapes down and shades the rock walls. Most carbonate sediment production does not come from calcareous epiphytes on the macroalgae but comes from the coralline algae and calcareous invertebrates living on the rock walls and in concealed depressions. Mollusks (gastropods and bivalves) and geniculate coralline algae with numerous lithoclasts, crustose coralline fragments, barnacle plates, serpulid worms, bryozoans, and large benthic foraminifers (especially Amphistegina) dominate the resultant gravels and sands; but there is little or no mud. This is because carbonate sediment is the result of production not only in the macrophyte factory but also in adjacent seagrass factories. Particles produced in the macroalgal factory are shed onto the adjacent seafloor, where they form the requisite sandy substrates for quick colonization by seagrasses. Thus, over time the sediment in this shallow but hydrodynaically energetic environment becomes a mixture of materials from the two sources with seagrasses contributing gastropods, large benthic foraminifers, spirorbids, bryozoans and articulated corallines to the sediment milieu. If

  20. Early Cretaceous Shallow-Water Platform Carbonates of the Bolkar Mountains, Central Taurides - South Turkey: Facies Analysis and Depositional Environments

    Science.gov (United States)

    Solak, Cemile; Taslı, Kemal; Koç, Hayati

    2016-10-01

    The study area comprises southern non-metamorphic part of the Bolkar Mountains which are situated in southern Turkey, eastern part of the Central Taurides. The studied five outcrops form geologically parts of the tectonostratigraphic units called as allochthonous Aladag Unit and autochthonous Geyikdagi Unit. The aim of this study is to describe microfacies and depositional environments of the Bolkar Mountains Early Cretaceous shallow- water platform carbonates. The Lower Cretaceous is represented by continuous thick- bedded to massive dolomite sequence ranging from 100 to 150 meters thick, which only contains locally laminated limestone intercalations in the Yüğlük section and thick to very thick-bedded uniform limestones ranging from approximately 50 to 120 meters, consist of mainly laminated- fenestral mudstone, peloidal-intraclastic grainstone-packstone, bioclastic packstone- wackestone, benthic foraminiferal-intraclastic grainstone-packstone, ostracod-fenestral wackestone-mudstone, dasycladacean algal packstone-wackestone and ooidal grainstone microfacies. Based on a combination sedimantological data, facies/microfacies and micropaleontological (predominantly dasycladacean algae and diverse benthic foraminifera) analysis, it is concluded that Early Cretaceous platform carbonates of the Bolkar Mountains reflect a tidally affected tidal-flat and restricted lagoon settings. During the Berriasian- Valanginian unfavourable facies for benthic foraminifera and dolomitization were predominate. In the Hauterivian-early Aptian, the effect of dolomitization largely disappeared and inner platform conditions still prevailed showing alternations of peritidal and lagoon facies, going from peritidal plains (representing various sub-environments including supratidal, intertidal area, tidal-intertidal ponds and ooid bars) dominated by ostracod and miliolids, to dasycladacean algae-rich restricted lagoons-subtidal. These environments show a transition in the vertical and

  1. Depositional environment, ichnological features and oxygenation of Permian to earliest Triassic marine sediments in central Spitsbergen, Svalbard

    Directory of Open Access Journals (Sweden)

    Alfred Uchman

    2016-05-01

    Full Text Available Late Early Permian–lowermost Triassic carbonate, siliceous (spiculites and clastic marine sediments in the Marmierfjellet area (Isfjorden, central Spitsbergen contain a relatively diverse and abundant trace fossil assemblage providing important information about the depositional processes. The Vøringen Member (Late Artinskian–Kungurian of the Kapp Starostin Formation (Late Artinskian–? Changhsingian contains trace fossils (Nereites, Phycosiphon, Zoophycos and Arenicolites—common in tempestites typical of the proximal–archetypal Cruziana ichnofacies, which indicates lower shoreface. Nereites, Phycosiphon and Zoophycos, accompanied by other rare trace fossils, characterize the Svenskegga and Hovtinden members of the Kapp Starostin Formation. They are interpreted as the distal Cruziana ichnofacies, possibly transitional to the Zoophycos ichnofacies typical of the lower offshore zone. However, the sporadic occurrences of Arenicolites and Macaronichnus can point to episodic shallowing to upper offshore–lower shoreface. The lowest part of the Triassic Vikinghøgda Formation (Induan–Olenekian contains a very low-diverse ichnoassemblage composed of a few simple and branched forms ascribed to the impoverished Cruziana ichnofacies (lower to upper offshore environment, which is attributed to the early recovery stage after the Permian–Triassic extinction. The trace fossils and loss of primary sedimentary structures caused by intense bioturbation throughout most of the section point to generally oxygenated pore waters on the sea floor. However, some horizons, especially laminated black shales, display reduced or no bioturbational activity. These horizons also show high V/(V+Ni ratios, which indicate oxygen-depleted sediments with periods of anoxic conditions. A remarkable black shale unit deposited under anoxic and sulphidic conditions occurs at the Permian–Triassic transition.

  2. Microfaunal evidence of age and depositional environments of the Cerro Prieto section (Plio-Pleistocene), Baja California, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Ingle, J.C. Jr.

    1982-01-01

    Microfossils including benthic and planktic foraminifera, ostracodes, calcareous algae, fish skeletal material, and fragments of pelecypods were found in 14 core samples from depths of 185 to 1952 m in the Cerro Prieto geothermal field, providing evidence of both the age and depositional history of sediments comprising the 3000-m-thick Pliocene and Pleistocene section in this area. Ostracodes of brackish water and marine origin constitute the most common microfossils present in this sequence occurring in 8 samples; in situ littoral and neritic species of benthic foraminifera occur in 5 samples with planktic species present in 2 samples. Distributional patterns of ostracodes and foraminifera together with previously analyzed lithofacies (Lyons and van de Kamp, 1980) indicate that the Cerro Prieto section represents an intertonguing complex of alluvial, deltaic, estuarine, and shallow marine environments deposited along the front of the Colorado River delta as it prograded across the Salton Trough during Pliocene and Pleistocene time. Foraminiferal evidence indicates that a sand and shale unit commonly present at depths between 700 and 1100 m represents a significant mid-Pleistocene marine incursion in the Cerro Prieto area. Tentative correlation of the Cerro Prieto section with the well dated Palm Springs Formation of the Imperial Valley, California area suggests that the Pliocene/Pleistocene boundary occurs at a depth of approximately 2000 m in the area of well M-93. Reworked specimens of Cretaceous foraminifera and fragments of the Cretaceous pelecypod Inoceramus were found in five samples further substantiating the Colorado Plateau provenance of a significant portion of the Colorado River deltaic sediments in the Cerro Prieto area.

  3. Sea Level Changes And Depositional Environments In The Izmit Gulf, Eastern Marmara Sea, During The Late Glacial-Holocene Period

    Science.gov (United States)

    Cagatay, M. N.; Görür, N.; Polonia, A.; Demirbag, E.; Sakinc, M.; Cormier, M. H.; Capotondi, L.; McHugh, C.; Emre, O.; Eris, K.

    2003-04-01

    Offshore and onshore stratigraphic studies, together with high-resolution shallow seismic reflection profiling and multibeam bathymetric mapping, were carried out in the western and central part of the Izmit Gulf. These studies indicate that the western Gulf Izmit was a fresh water environment as part of the Marmara "lake" during the late glaciation and early deglaciation until ~12 kyr BP, when the Marmara basin was inundated by the Mediterranean waters. Correlation of 14C-dated onshore and offshore stratigraphic units in the western Izmit Gulf indicates that generally coarse late glacial sediments overlie a marked erosion surface formed during the low water level of the Marmara "Lake". These coarse sediments are followed upwards by 10.4-7 kyr BP old transgressive and the late Holocene post-transgression mud units. The bathymetry and subbottom chirp profiles clearly show that the palaeoshoreline of this lake was located at -85 m, having been controlled by the bedrock sill depth of the Çanakkale Strait. Another palaeoshoreline observed -65 m on northern margin of the Western Izmit and Karamürsel basins was probably formed during the Younger Dryas sea-level still stand. The shelf areas during about this time were colonized by bioherms, which were drowned and disappeared after further rise of the sea level. The presence of a -65 m marine paleoshoreline in the Karamürsel basin indicate that the sill restricting this basin to the west was much deeper than its present -55 m level and placed further south. The Gölcük basin restricted by a -38 m sill to its west was not probably flooded by the marine waters until ~10 kyr BP. Onshore alluvial fan deposits include a 10-15 cm. thick layer at 18 m containing a mixture of bones, charcoal, marine shells and brick tiles. This layer, dated at 2875 +-85 yr BP (1049 +-82 BC), is believed to be a possible tsunami deposit.

  4. Organic petrology and geochemistry of Eocene Suzak bituminous marl, north-central Afghanistan: Depositional environment and source rock potential

    Science.gov (United States)

    Hackley, Paul C.; Sanfilipo, John

    2016-01-01

    Organic geochemistry and petrology of Eocene Suzak bituminous marl outcrop samples from Madr village in north-central Afghanistan were characterized via an integrated analytical approach to evaluate depositional environment and source rock potential. Multiple proxies suggest the organic-rich (TOC ∼6 wt.%) bituminous marls are ‘immature’ for oil generation (e.g., vitrinite Ro rock sulfur content is ∼2.3 wt.% whereas sulfur content is ∼5.0–5.6 wt.% in whole rock extracts with high polar components, consistent with extraction from S-rich Type IIs organic matter which could generate hydrocarbons at low thermal maturity. Low Fe-sulfide mineral abundance and comparison of Pr/Ph ratios between saturate and whole extracts suggest limited Fe concentration resulted in sulfurization of organic matter during early diagenesis. From these observations, we infer that a Type IIs kerogen in ‘immature’ bituminous marl at Madr could be generating high sulfur viscous oil which is seeping from outcrop. However, oil-seep samples were not collected for correlation studies. Aluminum-normalized trace element concentrations indicate enrichment of redox sensitive trace elements Mo, U and V and suggest anoxic-euxinic conditions during sediment deposition. The bulk of organic matter observed via optical microscopy is strongly fluorescent amorphous bituminite grading to lamalginite, possibly representing microbial mat facies. Short chain n-alkanes peak at C14–C16 (n-C17/n-C29 > 1) indicating organic input from marine algae and/or bacterial biomass, and sterane/hopane ratios are low (0.12–0.14). Monoaromatic steroids are dominated by C28clearly indicating a marine setting. High gammacerane index values (∼0.9) are consistent with anoxia stratification and may indicate intermittent saline-hypersaline conditions. Stable C isotope ratios also suggest a marine depositional scenario for the Suzak samples, consistent with the presence of marine foraminifera including

  5. Geochemical discrimination of the geotectonic environment of basaltic-andesitic volcanic rocks associated with the Laochang polymetallic ore deposit at Lancang, Yunnan

    Institute of Scientific and Technical Information of China (English)

    GAO Jianguo

    2006-01-01

    The Laochang polymetallic ore deposit at Lancang is one of the well known ancient ore deposits associated with volcanic rocks in the Sanjiang (Tri-river) region of Southwest China. Volcanic rocks are dominated by alkali basalt and trachyte basalt. There has long been a controversy on the environment of formation of basalts. Some scholars hold that the basalts were formed in a continental environment, some thought they were formed in an oceanic environment and others considered that the basalts were emplaced in a back-arc basin. This study focuses on the geochemical characteristics of the basalts on the basis of their major elements, REEs and trace elements. At the same time, strongly incompatible elements such as Ta, Th and Hf and their ratios were used to differentiate the geotectonic settings of basalts. The results showed that the basalts in the region studied were formed in a continental rift environment.

  6. Late Permian Palynology and depositional environment of Chintalapudi sub basin, Pranhita-Godavari basin, Andhra Pradesh, India

    Science.gov (United States)

    Jha, Neerja; Pauline Sabina, K.; Aggarwal, Neha; Mahesh, S.

    2014-01-01

    mire or periods of standing water. This flooding environment favoured the growth of herbaceous lycopsids, filicopsids and sphenopsids in the palaeomire. More or less similar environments of deposition have been deduced for both the sedimentary sequences on the basis of palynofacies analysis. Anaerobic, reducing, water logged peat-forming conditions have been inferred based on the abundance of phytoclasts. The relative abundance of structured organic matter implies the existence of a fairly dense vegetation cover in the hinterland. The charcoal fragments recovered from the present study area reflects a possible wildfire in the accumulated swamps or a wildfire in the hinterland after which the sediments were flushed by fluvial systems into the swamps.

  7. Depositional environment and sequence stratigraphy of the middle Jurassic deposits: case study of Navia section in the west Bojnurd, west of Kopet-Dagh

    Directory of Open Access Journals (Sweden)

    Neda Sarbaz

    2016-12-01

    Kashafrud Formation in this section is composed of two depositional sequence (DS1 and DS2. The lower boundary of the first sequence (DS1, based on angular unconformity (above Triassic limestone of Elika Formation and fluvial conglomerate deposits, is type I (SB1. The upper boundary of DS1 is SB2 and is located in proximal delta front deposits with no subaerial exposure evidences. The thickness of the first sequence is about 400 m and consists of LST, TST and HST. The LST is composed of continental sediments (137 m that is covered by transgressive surface. This surface reveals by massive shale (50 m of distal delta fronts and maximum flooding surface is located in the upper part of these deposits. HST (215 m is composed of 12 shallowing and coarsening parasequences. DS2 with thickness of about 349 m is separated from DS1with sequence boundary type 2. This depositional sequence is only composed of TST with Fm and Fl lithofacies that transitionally changes to deeper water black shale that follows by marl and fine grain carbonate sediments of the Chaman-Bid Formation. Therefore, the maximum flooding surface is probably located within the Chaman-Bid Formation. Interpreted sea level fluctuation curve of the study area can be related to regional geological history and sometimes can be relatively correlated with global sea level curve (Haq et al, 1987

  8. Inter- and intra-subject variability of kinetics of airway exhalation and deposition of particulate matter in indoor polluted environments.

    Science.gov (United States)

    Goldoni, Matteo; Acampa, Olga; Longo, Sonia; Poli, Diana; Tagliaferri, Sara; Corradi, Massimo; Renzulli, Francesco Saverio; Mutti, Antonio

    2012-04-01

    PM(2.5) generated by indoor combustion activities can contribute significantly to personal PM exposure. The aims of this study were: (1) to validate a device specifically designed to study the kinetics of particle exhalation and the percentage of airway particle deposition (%DEP) in polluted indoor environments (welding fumes, environmental tobacco smoke - ETS) and (2) to assess the intra- and inter-subject variability of the signal. The device was tested on 14 subjects exposed to welding fumes and 10 subjects exposed to environmental tobacco smoke (ETS), performing repeated measures at different environmental PM concentrations. The intra-subject variability of the signal for particles with diameter 0.3-1.0 μm showed a geometric mean of %CV always below 6%, despite the values of %DEP. In the welding fume study, the increase in airborne 0.5-1.0 μm PM concentrations between the consulting room and production department was explainable in terms of increased density due to the metallic composition of particles. The %DEP of 0.3-1.0 μm ETS particles decreased with airborne PM concentration due to the technical limits of a laser particle counter and the perturbation induced by the physical characteristics of ETS PM. However, also at those extreme conditions, the signal remained repeatable and the individual susceptibility to PM remained substantially unaltered. In conclusion, the versatility and portability of our device, together with the repeatability of the signal, confirmed that the kinetics of exhaled particles and %DEP could be routinely measured in polluted environments and used to define individual susceptibility to airborne particles. Copyright © 2011 Elsevier GmbH. All rights reserved.

  9. The Association of Anastomosed fluvial deposits and dinosaur tracks, eggs, and nests: Implications for the interpretation of floodplain environments and a possible survival strategy for ornithopods

    Energy Technology Data Exchange (ETDEWEB)

    Nadon, G.C. (Univ. of Wisconsin, Madison (United States))

    1993-02-01

    The St. Mary River Formation (Maastrichtian) consists of anastomosed fluvial deposits containing several hundred track-bearing beds. Paleontologic and sedimentologic analyses of these beds indicate that large herbivores, ornithopods, inhabited a seasonal wetland dominated by marshes and lakes. Shallow tracks in fine-grained sediments, formed as the sediments dewatered to the point of stiffness, display the highest resolution of detail. The preservation potential of tracks in anastomosed fluvial deposits is large because of the abundance of soft substrates to record the tracks and the occurrence of annual flooding to rapidly bury the footprints. Comparison of the St. Mary River Formation to other anastomosed fluvial deposits as old as the Early Jurassic confirms that tracks are common in this type of deposit. The variation in preservation of track types and depth of penetration raises the possibility that ornithopods employed a survival strategy involving seasonal wetlands. The wetlands provided an abundant food source and at the same time the combination of a soft substrate and flooded conditions would have effectively countered the superior speed and agility of large carnivores. The relatively common occurrence of ornithopod eggshells from anastomosed fluvial deposits suggests that the abundant food supply accompanying the wet season also made the wetlands an ideal location to rear young. These data can be used to refine the interpretations of depositional environment derived from the sediments by allowing estimates to be made regarding the early post-depositional conditions of the sediments. 95 refs., 7 figs., 1 tab.

  10. Corrosion of aluminium in copper-aluminium couples under a marine environment: Influence of polyaniline deposited onto copper

    Energy Technology Data Exchange (ETDEWEB)

    Vera, Rosa, E-mail: rvera@ucv.c [Instituto de Quimica, Facultad de Ciencias, Pontificia Universidad Catolica de Valparaiso, Avda. Brasil 2950, Casilla 4059, Valparaiso (Chile); Verdugo, Patricia [Departamento de Quimica y Bioquimica, Facultad de Ciencias, Universidad de Valparaiso, Av. Gran Bretana 1111, Valparaiso (Chile); Orellana, Marco; Munoz, Eduardo [Instituto de Quimica, Facultad de Ciencias, Pontificia Universidad Catolica de Valparaiso, Avda. Brasil 2950, Casilla 4059, Valparaiso (Chile)

    2010-11-15

    Research highlights: {yields} The presence of Polyaniline in the Al-Cu system produces a decrease in the oxygen reduction reaction. {yields} In the marine enviroment, aluminium in Al-Cu couples, suffers pitting and exfoliation. {yields} The aluminium deterioration increases with chloride and enviromental sulphur dioxide presence, mainly when it is united to bare copper. - Abstract: In this study, we examined how aluminium corrosion in Al-Cu/PANI galvanic couples in a marine environment is influenced by deposition of polyaniline (PANI) on copper. Polarization curves and immersion assays in 0.1 M NaCl were performed. The morphologies of etched Al and corrosion products were observed by SEM, and the Al ions in solution were quantified by atomic absorption spectroscopy. A reduction in aluminium damage due to galvanic corrosion was observed as a result of decreased effective area for the oxygen reduction reaction on Cu/PANI electrode. Furthermore, an electrochemical reduction of PANI from leucoemeraldine to emeraldine base is proposed.

  11. Lithofacies, depositional environments, regional biostratigraphy and age of the Chitarwata Formation in the Bugti Hills, Balochistan, Pakistan

    Science.gov (United States)

    Métais, Grégoire; Antoine, Pierre-Olivier; Baqri, S. R. Hassan; Crochet, Jean-Yves; De Franceschi, Dario; Marivaux, Laurent; Welcomme, Jean-Loup

    2009-02-01

    The Oligocene-early Miocene Chitarwata Formation records a critical interval of terrestrial sedimentation that predates the Siwalik deposits on the Potwar Plateau of north-central Pakistan. This Oligocene-early Miocene time interval has long been considered as lacking in the entire Indo-Pakistan region. The Chitarwata Formation is widely exposed in the Sulaiman Range, but has never been described in detail in the Sulaiman Lobe, where the famous fossiliferous strata called 'Bugti Bone Beds' have been known for over a century and half. The Chitarwata Formation represents coastal-delta at the base, and plain and fluvial environments at the top. Lithofacies and sedimentary structures of the Chitarwata Formation in the Bugti area are described in detail, and show a clearly distinct lithologic pattern, different from that reported from the Zinda Pir area. The Chitarwata Formation also records an important transition in the evolution of the drainage systems in the area during the late Paleogene and early Neogene. This transition from the west-flowing paleo-Indus fluvial system to the development of the ancestral Indus drainage system may explain the numerous hiatuses that characterize the Chitarwata Formation. The abundance of fossil mammals from the Chitarwata and overlying Vihowa formation in the Bugti Hills provides critical biochronologic information that sheds new light on biostratigraphic correlation with the Zinda Pir area and for the entire Sulaiman Range.

  12. Sedimentary and petrofacies analyses of the Amasiri Sandstone, southern Benue Trough, Nigeria: Implications for depositional environment and tectonic provenance

    Science.gov (United States)

    Okoro, A. U.; Igwe, E. O.; Nwajide, C. S.

    2016-11-01

    This study was undertaken to determine the depositional environment, provenance and tectonic setting for the Turonian Amasiri Sandstone, southern Benue Trough, Nigeria, using lithofacies analysis and re-appraisal of petrography of the sandstones. Local stratigraphy and field relationships show a thick succession of shales alternating with elongate/parallel sandstone ridges extending eastwards from Akpoha to Amasiri through Itigidi and Ugep to Apiapum areas. Lithofacies analysis reveals 9 lithofacies suggestive of storm (mass flow) and tidal shelf processes. These include dark grey to black laminated shale/silty mudstones, bioturbated mudstones, coquinoid limestones, very fine-grained bioturbated sandstones with shell hash/debris in places and limestone rip-up clasts, massive and chaotic sandy conglomerate with rip - up clasts, fine to medium-grained, parallel laminated sandstone, hummocky cross-stratified, massive, medium to coarse-grained sandstones, medium to very coarse-grained, planar cross-bedded sandstone, with clay-draped foresets and Ophiomorpha burrows, and coarse-grained trough cross-bedded sandstone. Petrofacies analysis identifies the sandstones as feldspathic and arkosic arenites. Ternary plot of framework mineralogy indicates derivation from an uplifted continental block related to the nearby Oban Massif and Cameroon Basement Complex.

  13. The Baganuur coal deposit, Mongolia. Depositional environments and paleoecology of a Lower Cretaceous coal-bearing intermontane basin in Eastern Asia

    Energy Technology Data Exchange (ETDEWEB)

    Dill, H.G. [Federal Institute for Geosciences and Natural Resources, P.O. Box 510163, D-30631 Hannover (Germany); Altangerel, S.; Bulgamaa, J.; Hongor, O. [Center of Geological Investigation, Ulaanbaatar 37, P.O. Box 318 (Mongolia); Khishigsuren, S.; Majigsuren, Yo.; Myagmarsuren, S. [Department of Geology and Mineralogy, School of Geology (Mongolia); Heunisch, C. [Geological Survey of Lower Saxony, P.O. Box 510163, D-30631 Hannover (Germany)

    2004-12-03

    The investigations involved geophysical, sedimentological, palynological, chemical and mineralogical studies, supported by field-based infrared spectrometry. The Baganuur Basin, Central Mongolia, is among the rift or pull-apart-basins, which subsided at the boundary between the Jurassic and the Lower Cretaceous in East Asia. During the Berriasian, peat accumulation began in the area under study in Central Mongolia. The palynoflora is akin to the Siberian palynological province. Based on the phytoclast assemblages and the ratios of total sulfur content to total organic content, marine transgressions into this intermontane basin may be ruled out. The coal interseam sediments were laid down prevalently under neutral to slightly alkaline conditions; only in some carbonaceous sediments, the pH of intrastratal solutions was lowered. Suboxic to anoxic conditions persisted during almost the entire Lower Cretaceous period in the Baganuur Basin. Based on the distribution of fining- and coarsening-upward sequences and the organic matter, the basin fill has been subdivided into seven depositional units (A: fluvial-swamp, B: fluvial-lacustrine, C: deltaic-fluvial, D: fluvial, E: fluvial-deltaic-lacustrine/floodplain (?), F: lacustrine-deltaic-swamp, G: swamp-fluvial). A conspicuous change in the fluvial-lacustrine regime and an increase in the sediment supply may be observed at the boundary between depositional units B and C. A strong uplift triggered the onset of an intensive delta sedimentation. Lithoclasts, heavy minerals (e.g., apatite, zircon, garnet, anatase, brookite, epidote, sphene, tourmaline) and phyllosilicates (e.g., kaolinite, smectite, mica, chlorite) attest to a mixing of detrital material. One provenance area was abundant in acidic plutonic rocks as shown by the granitic lithoclasts, the other in volcanic rocks, which produced the vitroclastic debris deposited as tephra fallout. Post-depositional alteration of the siliciclastic interseam sediments was favored

  14. The Drenchwater deposit, Alaska: An example of a natural low pH environment resulting from weathering of an undisturbed shale-hosted Zn-Pb-Ag deposit

    Science.gov (United States)

    Graham, G.E.; Kelley, K.D.

    2009-01-01

    The Drenchwater shale-hosted Zn-Pb-Ag deposit and the immediate vicinity, on the northern flank of the Brooks Range in north-central Alaska, is an ideal example of a naturally low pH system. The two drainages, Drenchwater and False Wager Creeks, which bound the deposit, differ in their acidity and metal contents. Moderately acidic waters with elevated concentrations of metals (pH ??? 4.3, Zn ??? 1400 ??g/L) in the Drenchwater Creek drainage basin are attributed to weathering of an exposed base-metal-rich massive sulfide occurrence. Stream sediment and water chemistry data collected from False Wager Creek suggest that an unexposed base-metal sulfide occurrence may account for the lower pH (2.7-3.1) and very metal-rich waters (up to 2600 ??g/L Zn, ??? 260 ??g/L Cu and ???89 ??g/L Tl) collected at least 2 km upstream of known mineralized exposures. These more acidic conditions produce jarosite, schwertmannite and Fe-hydroxides commonly associated with acid-mine drainage. The high metal concentrations in some water samples from both streams naturally exceed Alaska state regulatory limits for freshwater aquatic life, affirming the importance of establishing base-line conditions in the event of human land development. The studies at the Drenchwater deposit demonstrate that poor water quality can be generated through entirely natural weathering of base-metal occurrences, and, possibly unmineralized black shale.

  15. Depositional Environment of the Batuasih Formation on the Basis of Foraminifera Content: A Case Study in Sukabumi Region, West Java Province, Indonesia

    Directory of Open Access Journals (Sweden)

    M. Hendrizan

    2014-06-01

    Full Text Available DOI: 10.17014/ijog.v7i2.139The research was carried out on the sediments of the Batuasih Formation cropping out at Batuasih Village, Cibatu River, Padaarang Sukabumi. Data obtained from field observation, as well as foraminifera and sedimentology analyses conducted in the laboratory, were used to interpret its depositional environment. The investigation was focused on planktonic and benthic foraminiferal assemblages for depositional environment interpretation that might not be used by previous researchers. The Batuasih Formation is composed of black shaly claystone, where the lower part is rich in clay ball, and limestone intercalations in the upper part of the formation. In Cibatu Section, no clay balls is recognized in the lower part, but intercalations of limestone still occur. However, a contrast difference is found in Padaarang section, where green claystone interbeds with fine-grained sandstone. The Batuasih Formation conformably overlies the Walat Formation containing conglomerate. Foraminifera fossil found in the Batuasih Formation consists of bad preserved black benthic and planktonic foraminifera, more abundant towards the lower part of formation. Based on foraminifera assemblage comprising genus Uvigerina, Cibicides, Elphidium, Operculina, Bulimina, Bolivina, Eponides, and Neoconorbina, supported by sedimentology data, the Batuasih Formation was deposited in a shallow to deep marine environtment, during Early Oligocene (P19 time. Upwards to be the Rajamandala Formation, the depositional environment tends to be shallower gradually.

  16. Depositional environment and faunal assemblages of the reef-associated beachrock at Rameswaram and Keelakkarai Group of Islands, Gulf of Mannar, India

    Institute of Scientific and Technical Information of China (English)

    S. KRISHNA KUMAR; N. CHANDRASEKAR; P. SERALATHAN; PRINCE S. GODSON

    2011-01-01

    Reef-associated beachrocks from Rameswaram and Keelakkarai group of islands (Holocene)were studied to assess the depositional environment and faunal assemblages. The samples were collected from marine terraces and reef platforms. Granulometrically, they are coarse to medium grained, moderately to very well sorted and fine to very fine skewed in character. The fineskewed nature of the sediments suggests the prevalence of the environmental condition of low energy. The microfaunas associated in beachrock reflect the reefal environment of deposition. Bivariant plots show that the sediments were predominantly deposited under beach environment.The C-M pattern indicates that the sediments are deposited by rolling and graded suspension. The Visher diagram of the study area samples clearly shows the presence of a dominant single saltation, lack of population and no surface creep population. The low diversity and fair preservation of faunas reflect the transgressive phase and the shallow marine environmental condition. The commonly preserved species such as Quinqueloculina sp. and Triloculina sp. indicate the low-energy environmental conditions.

  17. Environment

    DEFF Research Database (Denmark)

    Valentini, Chiara

    2017-01-01

    The term environment refers to the internal and external context in which organizations operate. For some scholars, environment is defined as an arrangement of political, economic, social and cultural factors existing in a given context that have an impact on organizational processes and structures....... For others, environment is a generic term describing a large variety of stakeholders and how these interact and act upon organizations. Organizations and their environment are mutually interdependent and organizational communications are highly affected by the environment. This entry examines the origin...... and development of organization-environment interdependence, the nature of the concept of environment and its relevance for communication scholarships and activities....

  18. Effects of Hybrid and Non-hybrid Epichloë Endophytes and Their Associated Host Genotypes on the Response of a Native Grass to Varying Environments.

    Science.gov (United States)

    Jia, Tong; Oberhofer, Martina; Shymanovich, Tatsiana; Faeth, Stanley H

    2016-07-01

    Asexual Epichloë endophytes are prevalent in cool season grasses, and many are of hybrid origin. Hybridization of asexual endophytes is thought to provide a rapid influx of genetic variation that may be adaptive to endophyte-host grass symbiota in stressful environments. For Arizona fescue (Festuca arizonica), hybrid symbiota are commonly found in resource-poor environments, whereas non-hybrid symbiota are more common in resource-rich environments. There have been very few experimental tests where infection, hybrid and non-hybrid status, and plant genotype have been controlled to tease apart their effects on host phenotype and fitness in different environments. We conducted a greenhouse experiment where hybrid (H) and non-hybrid (NH) endophytes were inoculated into plant genotypes that were originally uninfected (E-) or once infected with either the H or NH endophytes. Nine endophyte and plant genotypic group combinations were grown under low and high water and nutrient treatments. Inoculation with the resident H endophyte enhanced growth and altered allocation to roots and shoots, but these effects were greatest in resource-rich environments, contrary to expectations. We found no evidence of co-adaptation between endophyte species and their associated host genotypes. However, naturally E- plants performed better when inoculated with the hybrid endophyte, suggesting these plants were derived from H infected lineages. Our results show complex interactions between endophyte species of hybrid and non-hybrid origin with their host plant genotypes and environmental factors.

  19. Structural, nanomechanical and variable range hopping conduction behavior of nanocrystalline carbon thin films deposited by the ambient environment assisted filtered cathodic jet carbon arc technique

    Energy Technology Data Exchange (ETDEWEB)

    Panwar, O.S., E-mail: ospanwar@mail.nplindia.ernet.in [Polymorphic Carbon Thin Films Group, Physics of Energy Harvesting Division, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Road, New Delhi - 110 012 (India); Rawal, Ishpal; Tripathi, R.K. [Polymorphic Carbon Thin Films Group, Physics of Energy Harvesting Division, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Road, New Delhi - 110 012 (India); Srivastava, A.K. [Electron and Ion Microscopy, Sophisticated and Analytical Instruments, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Road, New Delhi - 110 012 (India); Kumar, Mahesh [Ultrafast Opto-Electronics and Tetrahertz Photonics Group, CSIR-National Physical Laboratory, Dr. K. S. Krishnan Road, New Delhi - 110 012 (India)

    2015-04-15

    Highlights: • Nanocrystalline carbon thin films are grown by filtered cathodic jet carbon arc process. • Effect of gaseous environment on the properties of carbon films has been studied. • The structural and nanomechanical properties of carbon thin films have been studied. • The VRH conduction behavior in nanocrystalline carbon thin films has been studied. - Abstract: This paper reports the deposition and characterization of nanocrystalline carbon thin films by filtered cathodic jet carbon arc technique assisted with three different gaseous environments of helium, nitrogen and hydrogen. All the films are nanocrystalline in nature as observed from the high resolution transmission electron microscopic (HRTEM) measurements, which suggests that the nanocrystallites of size ∼10–50 nm are embedded though out the amorphous matrix. X-ray photoelectron spectroscopic studies suggest that the film deposited under the nitrogen gaseous environment has the highest sp{sup 3}/sp{sup 2} ratio accompanied with the highest hardness of ∼18.34 GPa observed from the nanoindentation technique. The film deposited under the helium gaseous environment has the highest ratio of the area under the Raman D peak to G peak (A{sub D}/A{sub G}) and the highest conductivity (∼2.23 S/cm) at room temperature, whereas, the film deposited under the hydrogen environment has the lowest conductivity value (2.27 × 10{sup −7} S/cm). The temperature dependent dc conduction behavior of all the nanocrystalline carbon thin films has been analyzed in the light of Mott’s variable range hopping (VRH) conduction mechanism and observed that all the films obey three dimension VRH conduction mechanism for the charge transport.

  20. Corrosion and runoff rates of Cu and three Cu-alloys in marine environments with increasing chloride deposition rate.

    Science.gov (United States)

    Odnevall Wallinder, Inger; Zhang, Xian; Goidanich, Sara; Le Bozec, Nathalie; Herting, Gunilla; Leygraf, Christofer

    2014-02-15

    Bare copper sheet and three commercial Cu-based alloys, Cu15Zn, Cu4Sn and Cu5Al5Zn, have been exposed to four test sites in Brest, France, with strongly varying chloride deposition rates. The corrosion rates of all four materials decrease continuously with distance from the coast, i.e. with decreasing chloride load, and in the following order: Cu4Sn>Cu sheet>Cu15Zn>Cu5Al5Zn. The patina on all materials was composed of two main layers, Cu2O as the inner layer and Cu2(OH)3Cl as the outer layer, and with a discontinuous presence of CuCl in between. Additional minor patina constituents are SnO2 (Cu4Sn), Zn5(OH)6(CO3)2 (Cu15Zn and Cu5Al5Zn) and Zn6Al2(OH)16CO3·4H2O/Zn2Al(OH)6Cl·2H2O/Zn5Cl2(OH)8·H2O and Al2O3 (Cu5Al5Zn). The observed Zn- and Zn/Al-containing corrosion products might be important factors for the lower sensitivity of Cu15Zn and Cu5Al5Zn against chloride-induced atmospheric corrosion compared with Cu sheet and Cu4Sn. Decreasing corrosion rates with exposure time were observed for all materials and chloride loads and attributed to an improved adherence with time of the outer patina to the underlying inner oxide. Flaking of the outer patina layer was mainly observed on Cu4Sn and Cu sheet and associated with the gradual transformation of CuCl to Cu2(OH)3Cl of larger volume. After three years only Cu5Al5Zn remains lustrous because of a patina compared with the other materials that appeared brownish-reddish. Significantly lower release rates of metals compared with corresponding corrosion rates were observed for all materials. Very similar release rates of copper from all four materials were observed during the fifth year of marine exposure due to an outer surface patina that with time revealed similar constituents and solubility properties. Copyright © 2013 The Authors. Published by Elsevier B.V. All rights reserved.

  1. Analysis and modelling of geological and economical parameters influencing mining of slovak magnesite deposits and its impact on the environment on the example of the Košice-Bankov deposit

    Directory of Open Access Journals (Sweden)

    Blišan Peter

    2003-09-01

    Full Text Available Magnesite deposits in Slovakia are mined economically using underground methods. Their reserves and output represent an important part of the world onst. Therefore, it is necessary to pay attention to the analysis and modelling of geological-economical and environmental parameters influencing the mining of slovak magnesite deposits.Quality of raw material or deposit is among crucial factors influencing the industrial output of magnesites. This parameter significantly influences the mining and processing technologies. New methods of prospecting, exploration and reserve calculations need the re-evaluation of existing criteria for the determination of economical importance. Modern technologies are capable to utilise also previous noneconomical parts of the deposit what causes a need for the re-evaluation of existing methods of ore reserves determination and for the introduction and testing of modern methods of the ore reserves determination.Impact on the environment is also an important aspect of the mining activity. It is necessary to monitor and evaluate this problem consequently. Many new environmental studies confirm a negative impact of the magnesite mining on the nature and human society. Therefore, beside the problems of analysis and modelling of geological- economical parameters, the analysis of environmental aspects of mining is also unevitable to be included into the solution of the project. Modern monitoring systems based on the geographic information systems (GIS are intensively used for such analysis at the present time. Their assistance during collecting, elaborating and evaluating the research results is recently to hardly be replaceable.

  2. Sheltered coastal environments as archives of paleo-tsunami deposits: Observations from the 2004 Indian Ocean tsunami

    Science.gov (United States)

    Andrade, Vanessa; Rajendran, Kusala; Rajendran, C. P.

    2014-12-01

    The 2004 earthquake left several traces of coseismic land deformation and tsunami deposits, both on the islands along the plate boundary and distant shores of the Indian Ocean rim countries. Researchers are now exploring these sites to develop a chronology of past events. Where the coastal regions are also inundated by storm surges, there is an additional challenge to discriminate between the deposits formed by these two processes. Paleo-tsunami research relies largely on finding deposits where preservation potential is high and storm surge origin can be excluded. During the past decade of our work along the Andaman and Nicobar Islands and the east coast of India, we have observed that the 2004 tsunami deposits are best preserved in lagoons, inland streams and also on elevated terraces. Chronological evidence for older events obtained from such sites is better correlated with those from Thailand, Sri Lanka and Indonesia, reiterating their usefulness in tsunami geology studies.

  3. Geochemical constraints on the depositional environment of Upper Devonian radiolarian cherts from Loei,north-eastern Thailand

    Institute of Scientific and Technical Information of China (English)

    Mongkol UDCHACHON; Hathaithip THASSANAPAK; Qinglai FENG; Chongpan CHONGLAKMANI

    2011-01-01

    Late Devonian radiolarian chert sequences in the Indochina block of north-eastern Thailand are exposed in a narrow belt located to the east of Loei province.The analyzed radiolarian cherts were collected from Chiang Klom,Sumnoi and Pha Samyod localities.They are characterized by high silica content (> 90wt.%),high aluminum content and low iron content (Al2O3/(Al2O3 + Fe2O3):geomeans 0.91,0.88 and 0.92).The Al/(A1 + Fe +Mn) values are high in both cherts and interbedded shales (geomean 0.89).High Si/(Si + Al+ Fe) ratios are observed in cherts (geomean 0.97) and slightly low in shales (geomean 0.69),whereas Fe2O3/TiO2 values are low (geomean 5.91).For rare earth element (REE) analysis,the cherts exhibit low La abundances (geomean 4.31,3.59 and 4.22),slightly negative Ce anomalies (Ce/Ce*:geomean 0.81,0.76 and 0.93),intermediate ratios of North American Shale Composite (NASC) normalized Lan/Cen (geomean 1.33,1.37 and 1.12) and intermediate Lan/Ybn values (0.79,0.94 and 1.22).In the interbedded shales,REE characteristics are more or less equal to the cherts.The results indicate that these late Devonian radiolarian cherts were deposited in a continental margin environment.High Si/(Si + Al + Fe) values indicate a biogenic origin of the cherts,however,additional silica content in the cherts could be the result of diagenetic alteration.Intermediate positive Eu anomalies (Eu/Eu*:geomean 1.32,1.25 and 1.44) are interpreted as the result of detrital feldspar contribution corresponding to the distinctive low content of Fe.Geological evidences from the field support volcanic activities during the Late Devonian-Early Carboniferous.Weathered materials and fragments of basalts and andesites would possibly be supplied to the basin during chert sedimentation.These geochemical constraints indicate that,in western portion of Indochina,deep marine basin was closed before Late Devonian which was followed by the incursion of Early Carboniferous orogeny.

  4. Subglacial hydrothermal alteration minerals in Jökulhlaup deposits of Southern Iceland, with implications for detecting past or present habitable environments on Mars.

    Science.gov (United States)

    Warner, Nicholas H; Farmer, Jack D

    2010-06-01

    Jökulhlaups are terrestrial catastrophic outfloods, often triggered by subglacial volcanic eruptions. Similar volcano-ice interactions were likely important on Mars where magma/lava may have interacted with the planet's cryosphere to produce catastrophic floods. As a potential analogue to sediments deposited during martian floods, the Holocene sandurs of Iceland are dominated by basaltic clasts derived from the subglacial environment and deposited during jökulhlaups. Palagonite tuffs and breccias, present within the deposits, represent the primary alteration lithology. The surface abundance of palagonite on the sandurs is 1-20%. X-ray diffraction (XRD) analysis of palagonite breccias confirms a mineral assemblage of zeolites, smectites, low-quartz, and kaolinite. Oriented powder X-ray diffractograms (alteration mineral assemblage is consistent with low temperature (100-140 degrees C) hydrothermal alteration of basaltic material within the subglacial environment. These results suggest that potential martian analog sites that contain a similar suite of hydrated minerals may be indicative of past hydrothermal activity and locations where past habitable environments for microbial life may be found.

  5. Rock magnetic investigation of loess deposits in the Eastern Qingling Mountains (central China) and its implications for the environment of early humans

    Science.gov (United States)

    Wang, Xiaoyong; Lu, Huayu; Zhang, Weiguo; Hu, Pengxiang; Zhang, Hongyan; Han, Zhiyong; Wang, Shejiang; Li, Baoguo

    2016-11-01

    The Luonan Basin, located in the transitional zone between temperate and subtropical China, is an important locality for human evolution during the early to middle Pleistocene. The loess deposits in the Luonan Basin contain numerous in situ lithic artefacts; the deposits also constitute suitable material for dating the artefacts and are potentially useful for reconstructing the climatic fluctuations which is important for studying the adaptation and occupation of the area by early humans. We carried out a combined rock magnetic and geochemical investigation of a loess sequence from the Liuwan Palaeolithic site in the Luonan Basin. The results indicate a mixture of magnetic minerals, including magnetite/maghemite and hematite/goethite. Magnetic susceptibility was used as a palaeoclimate proxy on the Chinese Loess Plateau; however, its application to the Luonan Basin may be problematic because the provenance of the loess parent material, as well as the depositional environment, differs from that of the Chinese Loess Plateau. We found that rock magnetic parameters related to the grain size of magnetic minerals, such as SIRM/χ and χARM/SIRM, are better palaeoclimatic indicators than magnetic susceptibility. Overall, the magnetic results, together with the results of bulk grain-size and chemical index of alteration, indicate that the interglacial environment of early humans in Luonan Basin was warmer and more humid than the coeval environment of the Chinese Loess Plateau.

  6. Evaluation of stress experienced by soldiers wearing chemical protective clothing during varying work loads in desert or tropical environments. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Hudgens, G.A.; Banderet, L.E.; Cadarette, B.S.

    1994-04-01

    A stress evaluation was conducted in a laboratory test in which the physiological and psychological reactions of soldiers were monitored while they wore either the standard battle dress overgarment (MOPPI) or the full complement of chemical protective clothing with mask (MOPPIV) and worked at low, moderate, or high work loads in simulated desert (hot and dry) or tropic (hot and humid) environments. The psychological instruments indicated greater stress responses for soldiers wearing MOPPIV than wearing MOPPI and for soldiers working at a high work load than working at a low work load. Chemical protective clothing, MOPPIV, Tropics, Desert, Psychological stress, Work load, MOPPI, Stress evaluation.

  7. Persistent and transient Listeria monocytogenes strains from retail deli environments vary in their ability to adhere and form biofilms and rarely have inlA premature stop codons.

    Science.gov (United States)

    Wang, Jingjin; Ray, Andrea J; Hammons, Susan R; Oliver, Haley F

    2015-02-01

    Based on recent risk assessments, up to 83% of listeriosis cases from deli meat in the United States are predicted to be from ready-to-eat deli meats contaminated during processing at retail grocery stores. Listeria monocytogenes is known to use sanitizer tolerance and biofilm formation to survive, but interplay of these mechanisms along with virulence potential and persistence mechanisms specific to deli environments had yet to be elucidated. In this study, 442 isolates from food and nonfood contact surfaces in 30 retail delis over 9 months were tested for inlA premature stop codons (PMSCs); inlA encodes InlA, which is necessary to cause listeriosis. A total of 96 isolates, composed of 23 persistent and 73 transient strains, were tested for adhesion and biofilm-forming ability and sanitizer tolerance. Only 10/442 isolates had inlA PMSCs (pdelis with other persistent strains. Most (7/10) PMSC-containing isolates were collected from food contact surfaces (pdelis (p<0.05). Persistent strains had enhanced adhesion on day 1 of a 5-day adhesion-biofilm formation assay. However, there was no significant difference in sanitizer tolerance between persistent and transient strains. Results suggest that foods contaminated with persistent L. monocytogenes strains from the retail environment are (1) likely to have wild-type virulence potential and (2) may persist due to increased adhesion and biofilm formation capacity rather than sanitizer tolerance, thus posing a significant public health risk.

  8. Depositional models of sandy debrites and turbidites of Palaeogene reservoir sands in deep-lacustrine environments, South China

    Science.gov (United States)

    Li, Y.; Chen, G.

    2013-12-01

    Two depositional models are proposed for deep-lacustrine petroleum reservior sands (Palaeogene) in the Fushan Sag, Beibuwan Basin, South China. This facies trend is used as a template for predicting the distribution of reservoir facies of the Fushan oilfield. Based on examination of 150m of conventional cores from 13 drilled wells, four depositional facies have been interpreted: (1) fine-grained massive sandstone with floating mudstone clasts and planar clast fabric (sandy debrite); (2) fine-grained sandstone and siltstone showing contorted bedding, sand injection, and ptygmatic folding (sandy slump), (3) fine-grained sandstone with thin layers of normal grading and flute casts (turbidite), and (4) mudstone with faint laminae (suspension fallout). Combined with multiple seismic attributes, two depositional models are characterized by (1) sublacustrine fan: thick turbidite units occur at the bottom of the western sag beneath a series of normal faults slope. (2) Thinner deposition of sandy debrites mainly distribute at the bottom of eastern sag far from sandy slump at the lake margin slope, which interpreted to be controlled by "two-step" flexure slope break. The transfer zone located in the centre area is confirmed to be the primary origin for such differential depositions. In our study area, sandy debrites constitute the producing petroleum reservoirs, but turbidites are non reservoirs. This dramatic understanding will well account for "eastern much more than western" distribution of proven petroleum reserves and be applicable to predicting reservoir distribution.

  9. Effective Learning Strategies for the Recognition of Characters and Words by Learners of Chinese with Varying Proficiency in Different Learning Environments

    Directory of Open Access Journals (Sweden)

    Jing Wang

    2016-10-01

    Full Text Available The present study gauges effective strategies for recognizing characters and words by learners of Chinese as a foreign language. Besides answering background questions, 203 participants completed a questionnaire, a vocabulary recognition test, and a vocabulary checklist. The vocabulary test was found to be valid and reliable, and six categories of learning strategies were generated from the questionnaire. With the two background variables of language proficiency and language environment (studying abroad versus studying at home, the six strategy categories explained 48% of the variance in vocabulary recognition. Specifically, “frequent meaningful interaction with characters and words” positively predicted vocabulary recognition, whereas “focusing on character orthography” and “focusing on character pronunciation” negatively predicted it. The individual strategy of typing characters positively predicted vocabulary recognition, whereas using Pinyin to help remember pronunciation negatively predicted it. Pinyin can facilitate vocabulary recognition through typing characters yet may hinder it if excessively relying on Pinyin for pronunciation.

  10. Bacterial communities in termite fungus combs are comprised of consistent gut deposits and contributions from the environment

    DEFF Research Database (Denmark)

    Otani, Saria; Hansen, Lars Hestbjerg; Sørensen, Søren J

    2016-01-01

    Fungus-growing termites (subfamily Macrotermitinae) mix plant forage with asexual spores of their plant-degrading fungal symbiont Termitomyces in their guts and deposit this blend in fungus comb structures, within which the plant matter is degraded. As Termitomyces grows, it produces nodules...... with asexual spores, which the termites feed on. Since all comb material passes through termite guts, it is inevitable that gut bacteria are also deposited in the comb, but it has remained unknown which bacteria are deposited and whether distinct comb bacterial communities are sustained. Using high......-throughput sequencing of the 16S rRNA gene, we explored the bacterial community compositions of 33 fungus comb samples from four termite species (three genera) collected at four South African geographic locations in 2011 and 2013. We identified 33 bacterial phyla, with Firmicutes, Bacteroidetes, Proteobacteria...

  11. Rheological investigation of the shear strength, durability, and recovery of alginate rafts formed by antacid medication in varying pH environments.

    Science.gov (United States)

    Elliott, Brooke M; Steckbeck, Kathleen E; Murray, Lisa R; Erk, Kendra A

    2013-11-30

    The mechanical response of alginate rafts formed by mixing liquid alginate antacid medication (Gaviscon Extra Strength Liquid Antacid) with acidic solutions was investigated by deforming isolated rafts in a shear rheometer. As rafts were deformed to varying magnitudes of applied strain, rheological parameters were identified and related to the overall strength, durability, and recoverability of rafts formed at different pH (1.1-1.7) and aging conditions (0.5-4 h). Rafts formed in the lowest acidity solutions (pH 1.4, 1.7) were elastically weak ( G'₀ = 60 , 42 Pa for un-aged raft) yet maintained their elasticity during applied shear deformation to large values of strain (γc∼90%, 50%, where G'≈G″), and displayed a low-to-moderate level of elastic recovery following large-strain deformation. Rafts formed in the highest acidity solution had the greatest strength ( G'₀ = 500 Pa for un-aged raft and 21.5 kPa for rafts after 0.5 h of aging), reduced durability (γc∼2.5%, independent of aging), and displayed the greatest recoverability. A trade-off existed between un-aged raft strength and durability while recovery was dependent on durability, solution pH, and age. Rheometry-based evaluations of alginate rafts could be used for the informed design of future gastric retention and antacid products.

  12. Automatic Traffic Data Collection under Varying Lighting and Temperature Conditions in Multimodal Environments: Thermal versus Visible Spectrum Video-Based Systems

    Directory of Open Access Journals (Sweden)

    Ting Fu

    2017-01-01

    Full Text Available Vision-based monitoring systems using visible spectrum (regular video cameras can complement or substitute conventional sensors and provide rich positional and classification data. Although new camera technologies, including thermal video sensors, may improve the performance of digital video-based sensors, their performance under various conditions has rarely been evaluated at multimodal facilities. The purpose of this research is to integrate existing computer vision methods for automated data collection and evaluate the detection, classification, and speed measurement performance of thermal video sensors under varying lighting and temperature conditions. Thermal and regular video data was collected simultaneously under different conditions across multiple sites. Although the regular video sensor narrowly outperformed the thermal sensor during daytime, the performance of the thermal sensor is significantly better for low visibility and shadow conditions, particularly for pedestrians and cyclists. Retraining the algorithm on thermal data yielded an improvement in the global accuracy of 48%. Thermal speed measurements were consistently more accurate than for the regular video at daytime and nighttime. Thermal video is insensitive to lighting interference and pavement temperature, solves issues associated with visible light cameras for traffic data collection, and offers other benefits such as privacy, insensitivity to glare, storage space, and lower processing requirements.

  13. Growth and characterization of nanocrystalline SrTiO x films: room temperature deposition using RF sputtering system in a pure argon environment

    Science.gov (United States)

    Bayrak, T.; Goldenberg, E.

    2017-05-01

    We report a comprehensive description of the structure, optical and electrical properties of as-deposited and annealed SrTiO x (STO) thin films. Nanocrystalline STO films were deposited on p-type Si (1 0 0) and UV-grade fused silica substrates by RF magnetron sputtering at room temperature in a pure argon environment. Well adhered and transparent films with very smooth surfaces were obtained. As-deposited films showed 70% transparency in the visible spectrum, transparency increased to 77% after annealing at 700 °C. The direct and indirect optical band gaps were found to be 2.88 eV and 2.44 eV, for as-deposited films. For annealed films, indirect band gap increased to 2.57 eV while the direct optical band gap value remained constant. Upon annealing, the refractive indices (n) of the films decreased from 2.36 to 2.32. Ag/STO/p-Si device structures were also fabricated and characterized by current-voltage, capacitance-voltage and dielectric measurements. The calculated values are compared with experimental data from the literature and discussed in terms of device performances. A butterfly loop-type hysteresis curve was observed for the voltage-dependent capacitance measurement in annealed thin film devices. Dielectric constants were calculated as 31.7 and 57.4 for as-deposited and annealed films at 100 kHz, respectively. Charge storage capacity was found to be  >4.5 µC cm-2 for as-deposited and 3.5 µC cm-2 for annealed films.

  14. Adaptation to a seasonally varying environment: a strong latitudinal cline in reproductive diapause combined with high gene flow in Drosophila montana

    Science.gov (United States)

    Tyukmaeva, Venera I; Salminen, Tiina S; Kankare, Maaria; Knott, K Emily; Hoikkala, Anneli

    2011-01-01

    Adaptation to seasonal changes in the northern hemisphere includes an ability to predict the forthcoming cold season from gradual changes in environmental cues early enough to prepare for the harsh winter conditions. The magnitude and speed of changes in these cues vary between the latitudes, which induces strong selection pressures for local adaptation. We studied adaptation to seasonal changes in Drosophila montana, a northern maltfly, by defining the photoperiodic conditions leading to adult reproductive diapause along a latitudinal cline in Finland and by measuring genetic differentiation and the amount of gene flow between the sampling sites with microsatellites. Our data revealed a clear correlation between the latitude and the critical day length (CDL), in which half of the females of different cline populations enter photoperiodic reproductive diapause. There was no sign of limited gene flow between the cline populations, even though these populations showed isolation by distance. Our results show that local adaptation may occur even in the presence of high gene flow, when selection for locally adaptive life-history traits is strong. A wide range of variation in the CDLs of the fly strains within and between the cline populations may be partly due to gene flow and partly due to the opposing selection pressures for fly reproduction and overwinter survival. This variation in the timing of diapause will enhance populations’ survival over the years that differ in the severity of the winter and in the length of the warm period and may also help them respond to long-term changes in environmental conditions. PMID:22393492

  15. Depositional environments inferred from variations of calcium carbonate, organic carbon, and sulfide sulfur: a core from southeastern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Paropkari, A; Iyer, S.D.; Chauhan, O.S; PrakashBabu, C.

    The variations in CaCO3 and organic carbon and their inter-relationship in a core from the southeastern Arabian Sea (water depth 2,212 m) have been used to demarcate the Holocene/Pleistocene boundary; an increased terrigenous deposition during Late...

  16. Geochemical and fluid zonation in the skarn environment at the tomboy-minnie gold deposits, Lander County, Nevada

    Science.gov (United States)

    Theodore, T.G.; Howe, S.S.; Blake, D.W.; Wotruba, P.R.

    1986-01-01

    The Tomboy-Minnie gold deposits are related to the middle Tertiary porphyry copper system centered at Copper Canyon. Gold-silver ores in the deposits occur mostly in a pyrrhotite- and pyrite-rich basal 30-m-thick sequence of altered calcareous conglomerate belonging to the Middle Pennsylvanian Battle Formation. The entire mineralized system contained at least 3.3 million troy oz gold before large-scale mining operations began. Alteration in the Tomboy-Minnie deposits includes actinolite- and chlorite-dominant assemblages, in marked contrast to the skarn, potassic, and phyllic assemblages characterizing the copper-gold-silver deposits of the system. Introduction of gold occurred penecontemporaneously with replacement of early diopside-alteration assemblages by actinolite and chlorite. Metals are zoned strongly in the Copper Canyon system: the West and East ore bodies occur in a copper-gold-silver zone that is followed outward by a gold-silver zone which includes the Tomboy deposit and in turn, is succeeded by a lead-zinc-silver zone. Locations of drill holes that have Au/Ag assay ratios of ??? 1 clearly outline the Tomboy-Minnie deposits within an area of rocks with Au/Ag ratios of ??? 0.5. Fluid-inclusion studies suggest wide variations in temperature and chemistry prevailed in the fluids associated with mineralization at the Tomboy. Early fluids associated with diopsidequartz assemblages probably were dominantly CaCl2-rich brines and were boiling at temperatures higher than 500??C. These fluids were progressively enriched in sodium and potassium over time, and during the hydrosilicate stages, temperatures probably ranged from 320 to 500??C at the time actinolite formed, and from 220 to 320??C at the time chlorite was dominant. Sulfur isotopic data suggest that sulfur, mostly from a magmatic or deep-seated crustal source, was transported by hydrothermal fluids as aqueous H2S with a ?? 34S of about 4 ?? 1??? to the West, East, and Tomboy deposits. ?? 1986.

  17. 100th anniversary special paper: Sedimentary mineral deposits and the evolution of earth's near-surface environments

    Energy Technology Data Exchange (ETDEWEB)

    Holland, H.D. [Harvard University, Cambridge, MA (United States). Dept. of Earth & Planetary Science

    2005-12-15

    The nature of sedimentary mineral deposits has evolved during Earth's history in concert with changes in the oxidation (redo) state of the ocean-atmosphere system, biological evolution, and the growing importance of geologically young accumulations of ore-grade material. There is now strong evidence that the atmosphere and the oceans were anoxic, or essentially anoxic, before 2.4 Ga. Banded iron formations (BIF) and the detrital uranium ores formed prior to 2.4 Ga are consistent with such a state. The period between 2.4 and 2.0 Ga is called the Great Oxidation Event by some. Its ores bear unmistakable marks of the presence of atmospheric O{sub 2}. Between 1.8 and 0.8 Ga the Earth system seems to have been remarkably stable. Sedimentary ore deposits of this period were influenced by the presence of O{sub 2}. BIF, sedimentary manganese, and phosphorites disappeared ca. 1.8 Ga, but sedimentary exhalative (SEDEX) deposits and unconformity-type uranium deposits flourished, and nonsulfide zinc deposits put in an appearance. The period between 0.8 Ga and the end of the Proterozoic at 0.54 Ga was as turbulent or more so than the Paleoproterozoic. BIF returned, as did sedimentary manganese deposits and phosphorites. A further rise in the O{sub 2} content of the atmosphere and an increase in the sulfate concentration of seawater during this period brought the composition of the atmosphere and of seawater close to their present redox state. The last 540 m.y. of Earth's history have seen the system pass through two supercycles of roughly equal length. Climate, the redox stratification of the oceans ocean mixing, and the nature of sedimentary ores were influenced by tectonically and volcanically driven changes during these supercycles. The evolution of the higher land plants gave rise to coal deposits and sandstone-type uranium ores and was important for the formation of bauxites.

  18. The Use of Video Cases in a Multimedia Learning Environment for Facilitating High School Students' Inquiry into a Problem from Varying Perspectives

    Science.gov (United States)

    Zydney, Janet Mannheimer; Grincewicz, Amy

    2011-12-01

    This study investigated the connection between the use of video cases within a multimedia learning environment and students' inquiry into a socio-scientific problem. The software program was designed based on principles from the Cognitive Flexibility Theory (CFT) and incorporated video cases of experts with differing perspectives. Seventy-nine 10th-grade students in an urban high school participated in this study. After watching the expert videos, students generated investigative questions and reflected on how their ideas changed over time. This study found a significant correlation between the time students spent watching the expert videos and their ability to consider the problem's perspectives as well as their ability to integrate these perspectives within their questions. Moreover, problem-solving ability and time watching the videos were detected as possible influential predictors of students' consideration of the problem's perspectives within their questions. Although students watched all video cases in equivalent ways, one of the video cases, which incorporated multiple perspectives as opposed to just presenting one perspective, appeared most influential in helping students integrate the various perspectives into their own thinking. A qualitative analysis of students' reflections indicated that many students appreciated the complexity, authenticity, and ethical dimensions of the problem. It also revealed that while the majority of students thought critically about the problem, some students still had naïve or simplistic ways of thinking. This study provided some preliminary evidence that offering students the opportunity to watch videos of different perspectives may influence them to think in alternative ways about a complex problem.

  19. Sedimentary and microfaunal evolution in the Quaternary deposits in El Akarit river mouth (Gulf of Gabes, Tunisia): Paleo-environments and extreme events

    Science.gov (United States)

    Ben Rouina, Soumaya; Bassetti, Maria Angela; Touir, Jamel; Trabelsi, Khaled; Berne, Serge

    2016-09-01

    The quantitative study of ostracod and benthic foraminifera assemblages coupled with sedimentary facies, of the AK1 core (6 m-long) retrieved from the El Akarit prodelta (Gulf of Gabes, SE Tunisia) at an elevation of 0 m, enabled us to better understand the dynamics of depositional environments and to identify different stages of the Akarit river mouth evolution. Two major steps were identified: the first (>40,000 yr BP) possibly coincides with the Marine Isotope Stage 5e, onlapping continental Pleistocene deposits. It allowed the settlement of an open lagoon rich in marine microfauna that has become progressively more confined. The second one, late Holocene in age (last 3000 yr BP) is the succession of three extreme events episodes, characterized by very high-energy hydrodynamics and possibly linked to the occurrence of major storms and/or floods.

  20. Efficacy of drug detection by fully-trained police dogs varies by breed, training level, type of drug and search environment.

    Science.gov (United States)

    Jezierski, Tadeusz; Adamkiewicz, Ewa; Walczak, Marta; Sobczyńska, Magdalena; Górecka-Bruzda, Aleksandra; Ensminger, John; Papet, Eugene

    2014-04-01

    Some recent publications claim that the effectiveness of police canine drug detection is uncertain and likely minimal, and that the deterrent effect of dogs on drug users is low. It is also claimed that more scientific evidence is needed to demonstrate to what extent dogs actually detect drugs. The aim of this research was to assess experimentally, but in actual training and testing environments used by the Polish police, how effective dogs trained by the police were at illicit substance detection depending on factors such as type of drug, dog breed, dog experience with the searching site, and drug odor residuals. 68 Labrador retrievers, 61 German shepherds, 25 Terriers and 10 English Cocker Spaniels, of both sexes in each breed, were used. Altogether 1219 experimental searching tests were conducted. On average, hidden drug samples were indicated by dogs after 64s searching time, with 87.7% indications being correct and 5.3% being false. In 7.0% of trials dogs failed to find the drug sample within 10min. The ranking of drugs from the easiest to the most difficult to detect was: marijuana, hashish, amphetamine, cocaine, heroin. German shepherds were superior to other breeds in giving correct indications while Terriers showed relatively poor detection performance. Dogs were equally efficient at searching in well-known vs. unknown rooms with strange (i.e., non-target novelty) odors (83.2% correct indications), but they were less accurate when searching outside or inside cars (63.5% and 57.9% correct indications respectively). During police examination trials the dogs made more false alerts, fewer correct indications and searching time was longer compared to the final stage of the training. The drug odor may persist at a site for at least 48h. Our experiments do not confirm the recent reports, based on drug users' opinions, of low drug detection efficiency. Usefulness of drug detection dogs has been demonstrated here, even if their effectiveness may not be 100%, but

  1. Quantifying the dry deposition of ammonia in ammonia-rich and ammonia-poor environments using a surrogate surface approach

    Science.gov (United States)

    Moumen, Nadjoua; Yi, Seung-Muk; Raymond, Heather A.; Han, YoungJi; Holsen, Thomas M.

    In this study, dry deposition samples were collected with both an aerodynamically smooth water surface (WSS) and a knife-edge surrogate surface (KSS) in Potsdam, NY, Solomons, MD, and at a farm in upstate NY intermittently between March 2000 and August 2001. The WSS and the citric acid-coated paper filter on the KSS were used to measure total ammonium deposition (NH 3 and p-NH 4+), while a greased Mylar disk on the KSS was used to measure particulate NH 4+ (p-NH 4+) deposition. An annular denuder system (ADS) was used to measure NH 3 gas phase and particulate NH 4+ concentrations. In side-by-side experiments with two WSSs, no statistical difference was found between simultaneously measured total ammonium deposition at any of the sites. Average total NH 3 fluxes measured with the WSS in Potsdam, Solomons, and at the farm were 3.1, 2.1, and 310 mg NH 4+ m -2 day -1, respectively. Similarly gaseous NH 3 fluxes measured with the citric acid-coated paper on the KSS were 3.6, 2.1, and 500 mg NH 4+m -2 day -1, respectively. The p-NH 4+ fluxes to the KSS-greased strip were negligible at all three locations. Fluxes measured by the citric acid paper filters were slightly greater than those measured with the WSS suggesting that the acidic dry surfaces had a higher affinity for ammonia than the water in the WSS. The average gas-phase ammonia concentrations in Potsdam, Solomons, MD and at the farm were 0.60×10 -3, 2.1×10 -3, and 0.25 mg NH 4+ m -3, respectively. The average ammonium concentrations were 0.50×10 -3, 1.2×10 -3, and 14×10 -3 mg NH 4+ m -3, respectively.

  2. Stratigraphic sections, depositional environments, and metal content of the upper part of the Middle Pennsylvanian Minturn Formation, Northern Sangre De Cristo Range, Custer and Saguache counties, Colorado

    Science.gov (United States)

    Clark, R.F.; Walz, D.M.

    1985-01-01

    The calcareous upper part of the 2,000-meter-thick Middle Pennsylvanian Minturn Formation (Lindsey and others, 1985) in the northern Sangre de Cristo Range is a key stratigraphic interval for correlating rocks and mapping the structure of the range. The stratigraphy of this complex and heretofore poorly known interval is reported here in order to provide a basis for correlation among the structural blocks in the range. Inferred depositional environments of the upper part of the Minturn Formation are described briefly.

  3. Organic Geochemical Characteristics and Depositional Environment of Aǧaçbaşi Plateau Peat, Köprübaşi/Trabzon, NE Turkey

    Science.gov (United States)

    Hoş Çebi, Fatma; Korkmaz, Sadettin

    2013-04-01

    Young peat deposits crop out in the southern part of the Aǧaçbaşı region of Trabzon city, Northern Turkey. In this study, chemical, organic geochemical, petrographic and palynological features of the peat occurrences are investigated and results obtained evaluated. According to palynological investigations, it is determined that peats were occured in terrestrial or lacustrine environments, which is containing average of 80% woody, 15% herbaceous and 5% amorphous organic matter. Age of peats has been determined as Miocene or younger, by the palynological age determinations. It is understood from the obtained SCI (Sport Color Index) analysis results that constituting organic material of peat is immature. Total organic carbon content of the peat is average 41.69% by pyrolysis analysis. HI values were calculated as average 315.46 mgHC/gTOC, which is very high for the coal occurrences. The high OI values (avg. 134 mgCO2/gTOC) show that the environments of peat deposits were oxic or suboxic. TAR (Terrigenous/Aquatic Ratio) and CPI (Carbon Preference Index) index value, is found to be 2.4 and 3.4 respectively. These values that resulted from dominance of high-numbered n-alkanes, indicate terrestrial organic matter input. According to the m/z 191 and m/z 217 mass peaks of GC chromatogram data which is obtained by biomarker analysis, sterane/hopane ratio suggests algal organic matter. Moreover, the lack of C34 and C35 homohopans show that organic matter deposited under oxic or suboxic conditions. Moretane/hopane, Tm/Ts and Tm/C30 hopane ratios were calculated in order of 0.15, 3.25 and 0.33, respectively. These values imply acidic and oxic conditions during the formation of peat. Due to the absence of 17α(H)-28.30-bisnorhopan in the m/z 191 chromatograms, it is concluded that Aǧaçbaşı plateau peat might be deposited in a terrestrial or lacustrine environments under oxic or suboxic conditions. Dominant sterane content of C29 suggests terrestrial organic matter input

  4. Bitumen II from the Paleoproterozoic Here’s Your Chance Pb/Zn/Ag deposit: Implications for the analysis of depositional environment and thermal maturity of hydrothermally-altered sediments

    Science.gov (United States)

    Holman, Alex I.; Grice, Kliti; Jaraula, Caroline M. B.; Schimmelmann, Arndt

    2014-08-01

    The formation of sedimentary exhalative (SEDEX) Pb/Zn deposits is linked to ocean euxinia, but recent evidence suggests that ferruginous conditions may have dominated the deep ocean during the Middle Proterozoic, a maximum period for SEDEX distribution. Biomarkers of sulfate-reducing and sulfide-oxidising bacteria are valuable indicators of euxinic conditions in such settings. Organic matter (OM) from SEDEX deposits is often affected by alteration and/or migration, but OM entrapped within the kerogen/mineral matrix (Bitumen II) may be less affected than the freely-extractable OM (Bitumen I). We analysed Bitumen II from the Paleoproterozoic Here’s Your Chance (HYC) Pb/Zn/Ag deposit to find evidence of euxinic conditions in the depositional environment. n-Alkane distributions in Bitumen II are markedly distinct from previously-reported Bitumen I. Bitumen II contains long-chain n-alkanes (up to C36 or C38) and a strong even-over-odd distribution in a number of samples, which are 4‰ to 7‰ depleted in 13C compared to n-alkanes in Bitumen I and verified as indigenous by comparison with δ13C of isolated kerogen. These features are interpreted as evidence of sulfate-reducing and sulfide-oxidising bacteria, confirming that HYC was deposited under euxinic conditions. Bitumen II has the potential to reveal information from OM that is degraded and/or overprinted in Bitumen I. Commonly-used methylphenanthrene maturity ratios give conflicting information as to the relative maturity of Bitumens I and II. Bitumen I contains a far higher proportion of methylated phenanthrenes than Bitumen II. As Bitumen II is sequestered within the kerogen/mineral matrix it may have restricted access to the ‘methyl pool’ of organic compounds that can donate methyl groups to aromatic hydrocarbons. Parameters that include both phenanthrene and methylphenanthrenes do not appear suitable to compare the maturity of Bitumens I and II; hence there is no clear evidence that Bitumen II is of

  5. A 90 m-thick coal seam in the Lubstow lignite deposit (Central Poland): palynological analysis and sedimentary environment

    Energy Technology Data Exchange (ETDEWEB)

    Durska, E. [University of Warsaw, Warsaw (Poland). Faculty of Geology

    2008-07-01

    A 90 m-thick brown coal seam, the result of organic matter deposition in a fault-trough, is exploited in an open cast mine at Lubstow (Central Poland). Palynological analysis was conducted in order to determine which plants were the source of organic matter forming such a thick coal bed. The pollen spectrum is dominated by the gymnosperm pollen Inaperturopollenites, produced by trees closely related to the extant genera Taxodium and Glyptostrobus, the dominant constituents of swamp forests in SE North America and SE Asia today. However the lack of xylites and preserved tissues in the coal does not support the conception of a swamp forest as the peat-producing community. There is also significant percentage of angiosperm pollen in the coal, mainly from the groups: Castaneoideapollis, Tricolporopollenites exactus and T. pseudocingulum. The plants producing these pollen were probably the main constitutent of the peat-producing community. The community shows signs of a shrub swamp with local tree islands and a low water table. Evidence for this also includes the detrital type of coal, the lack of preserved plant tissues and the presence of fungal remains. The characteristics show the existence of aerobic zones at the time of peat production. The peat was probably derived from angiosperms. Dome-shaped forms in the upper part of the deposit are the remains of tree islands. As detritus accumulation is very on the surfaces of present-day tree islands, a similar rate of deposition may have taken place during peat production at Lubstow. This, combined with subsidence in the fault-through, explains the great thickness of the coal bed.

  6. Rational engineering correlations of diffusional and inertial particle deposition behavior in non-isothermal forced convection environments

    Science.gov (United States)

    Rosner, D. E.; Gokoglu, S. A.; Israel, R.

    1982-01-01

    A multiparameter correlation approach to the study of particle deposition rates in engineering applications is discussed with reference to two specific examples, one dealing with thermophoretically augmented small particle convective diffusion and the other involving larger particle inertial impaction. The validity of the correlations proposed here is demonstrated through rigorous computations including all relevant phenomena and interactions. Such representations are shown to minimize apparent differences between various geometric, flow, and physicochemical parameters, allowing many apparently different physicochemical situations to be described in a unified way.

  7. Extensive microbial mats and their influences on the erosional and depositional dynamics of a siliciclastic cold water environment (Lower Arenigian, Montagne Noire, France)

    Science.gov (United States)

    Noffke, N.

    2000-11-01

    Lower Arenigian (Ordovician) rocks of the Montagne Noire, France, represent a shallow-marine environment of a high latitude position along the northern margin of Gondwana. Within the weakly metamorphosed siliciclastics six depositional units were recognized: (1) outer shelf; (2) foreshore zone, below wave base; (3) foreshore zone, above wave base; (4) sand bars of shoreface zone; (5) intertidal deposits; and (6) lagoonal zone. Wrinkle structures and various other phenomena were mediated by coherent (cyano-)bacterial mats. The structures can be related to the different facies zones of the paleoenvironment. Whereas the muddy outer shelf, and the high-energetic sand bars were not overgrown by any mat-constructing microbial populations, fine sands of the foreshore zone, the tidal flats and lagoonal areas were widely colonized. Restriction of mats due to competition of space by endobenthic macroorganisms, or by grazers was low. The microbially induced structures are composed of organic material, pyrite, clay minerals (illite, chamsonite, chlorite), and chert. The minerals precipitated in situ during degradation of the organic layers by the activity of heterotrophic bacteria at low temperatures. Because the microorganisms formed a dense organic carpet covering extensive areas of the ancient sea-bottom, they influenced significantly the erosional and depositional dynamics of the sedimentary system of the local Arenigian. Biostabilization counteracted erosion, and baffling, trapping and binding enriched mineral particles. Additionally, the in situ formed minerals contributed to the total amount of sediment. The biotic influence lead to increased accumulation of sediment within the depositional area. The study shows that microbial mats of great extension occur within Phanerozoic siliciclastics of cold paleoclimate zones, and that preservation of the mat fabrics was possible. The significant mats influenced the local sedimentary system, an aspect scarcely taken into account

  8. 中国矿山环境治理恢复保证金制度%Deposit System of Mining Environment Restoration in China

    Institute of Scientific and Technical Information of China (English)

    燕守广; 沈渭寿; 邹长新

    2012-01-01

    Current Chinese environmental policies can not solve the main problems of mining environment fundamentally. The mining companies, main subjects of the responsibility, lack the initiatives to protect and restore the environment. Deposit of Min- ing Environment Restoration is a fund to ensure the mining companies to perform their obligations of implementing environmental protection and restoration. It is a special economic means. The intention of establishing the deposit system is to promote the min- ing companies to protect environment during mining, and restore the ecological environment when the mine is closed. Implementa- tion of this system will internalize the external costs of mineral resources exploitation. It is an effective and necessary form to pro- tect the mining environment.%由于中国当前的矿山环境保护政策尚不能从根本上解决矿山环境的主要问题,作为责任主体的矿山企业不能积极主动实施矿山环境治理与恢复。矿山环境治理恢复保证金是为了保证采矿权人履行矿山环境治理恢复义务而缴纳的资金。建立矿山环境治理恢复保证金制度就是为了贯彻“谁污染、谁治理;谁破坏,谁恢复”的环保原则,促进采矿权人在采矿过程中保护矿山环境,并确保在闭坑、停办、关闭后受破坏的矿山生态环境得到治理恢复的一项特别的经济手段和措施。实施保证金制度可以更好地促进矿产资源开发的外部成本内部化,是矿山环境保护必要且有效的形式。

  9. Time Varying Feature Data

    Science.gov (United States)

    Echterhoff, J.; Simonis, I.; Atkinson, R.

    2012-04-01

    The infrastructure to gather, store and access information about our environment is improving and growing rapidly. The increasing amount of information allows us to get a better understanding of the current state of our environment, historical processes and to simulate and predict the future state of the environment. Finer grained spatial and temporal data and more reliable communications make it easier to model dynamic states and ephemeral features. The exchange of information within and across geospatial domains is facilitated through the use of harmonized information models. The Observations & Measurements (O&M) developed through OGC and standardised by ISO is an example of such a cross-domain information model. It is used in many domains, including meteorology, hydrology as well as the emergency management. O&M enables harmonized representation of common metadata that belong to the act of determining the state of a feature property, whether by sensors, simulations or humans. In addition to the resulting feature property value, information such as the result quality but especially the time that the result applies to the feature property can be represented. Temporal metadata is critical to modelling past and future states of a feature. The features, and the semantics of each property, are defined in domain specific Application Schema using the General Feature Model (GFM) from ISO 19109 and usually encoded following ISO 19136. However, at the moment these standards provide only limited support for the representation and handling of time varying feature data. Features like rivers, wildfires or gas plumes have a defined state - for example geographic extent - at any given point in time. To keep track of changes, a more complex model for example using time-series coverages is required. Furthermore, the representation and management of feature property value changes via the service interfaces defined by OGC and ISO - namely: WFS and WCS - would be rather complex

  10. The Eocene Rusayl Formation, Oman, carbonaceous rocks in calcareous shelf sediments: Environment of deposition, alteration and hydrocarbon potential

    Energy Technology Data Exchange (ETDEWEB)

    Dill, H.G.; Wehner, H.; Kus, J. [Federal Institute for Geosciences and Natural Resources, P.O. Box 510163, D-30631 Hannover (Germany); Botz, R. [University Kiel, Geological-Paleontological Department, Olshausenstrasse 40-60, D-24118 Kiel (Germany); Berner, Z.; Stueben, D. [Technical University Karlsruhe, Institute for Mineralogy and Geochemistry, Fritz-Haber-Weg 2, D-76131 Karlsruhe (Germany); Al-Sayigh, A. [Sultan Qaboos University, Geological Dept. PO Box 36, Al-Khod (Oman)

    2007-10-01

    Paralic carbonaceous series intercalated among calcareous shelf sediments have seldom been investigated. During the early Eocene, calcareous and siliciclastic sediments were deposited on a wide shelf in front of low-reliefed hinterland in the Al Khawd region in NE Oman. The siliciclastic-calcareous sediments originated from strongly reworked debris of the Arabic Shield. The underlying Semail Ophiolite did not act as a direct source of debris but provided some heat to increase the maturity of carbonaceous rocks and modify the isotope signal of the calcareous minerals in the Rusayl Formation. A multidisciplinary approach involving sedimentology, mineralogy, chemistry, coal petrography and paleontology resulted in the establishment of nine stratigraphic lithofacies units and provides the reader with a full picture from deposition of the mixed carbonaceous-calcareous-siliciclastic rocks to the most recent stages of post-depositional alteration of the Paleogene formations. The calcareous Jafnayn Formation (lithofacies unit I) developed in a subtidal to intertidal regime, influenced episodically by storms. Deepening of the calcareous shelf towards younger series was ground to a halt by paleosols developing on a disconformity (lithofacies unit II) and heralding the onset of the Rusayl Formation. The stratigraphic lithofacies units III and IV reflect mangrove swamps which from time to time were flooded through washover fans from the open sea. The presence of Spinozonocolpites and the taxon Avicennia, which today belong to a coastal marsh vegetational community, furnish palynological evidence to the idea of extensive mangrove swamps in the Rusayl Formation [El Beialy, S.Y., 1998. Stratigraphic and palaeonenvironmental significance of Eocene palynomorphs from the Rusayl Shale Formation, Al Khawd, northern Oman. Review of Palaeobotany and Palynology 102, 249-258]. During the upper Rusayl Formation (lithofacies units V through VII) algal mats episodically flooded by marine

  11. Solid waste deposits as a significant source of contaminants of emerging concern to the aquatic and terrestrial environments - A developing country case study from Owerri, Nigeria

    Energy Technology Data Exchange (ETDEWEB)

    Arukwe, Augustine, E-mail: arukwe@bio.ntnu.no [Department of Biology, Norwegian University of Science and Technology (NTNU), Hogskoleringen 5, 7491 Trondheim (Norway); Eggen, Trine [Bioforsk, Norwegian Institute for Agricultural and Environmental Research, Postveien 213, N-4353 Klepp St. (Norway); Moeder, Monika [Helmholtz Centre for Environmental Research UFZ, Department of Analytical Chemistry, Permoserstrasse 15, D-04318 Leipzig (Germany)

    2012-11-01

    In developing countries, there are needs for scientific basis to sensitize communities on the problems arising from improper solid waste deposition and the acute and long-term consequences for areas receiving immobilized pollutants. In Nigeria, as in many other African countries, solid waste disposal by way of open dumping has been the only management option for such wastes. Herein, we have highlighted the challenges of solid waste deposit and management in developing countries, focusing on contaminants of emerging concern and leaching into the environment. We have analyzed sediments and run-off water samples from a solid waste dumping site in Owerri, Nigeria for organic load and compared these with data from representative world cities. Learning from previous incidents, we intend to introduce some perspective for awareness of contaminants of emerging concerns such as those with potential endocrine disrupting activities in wildlife and humans. Qualitative and quantitative data obtained by gas chromatography and mass spectrometric analysis (GC-MS) provide an overview on lipophilic and semi-polar substances released from solid waste, accumulated in sediments and transported via leachates. The chromatograms of the full scan analyses of the sediment extracts clearly point to contamination related to heavy oil. The homologous series of n-alkanes with chain lengths ranging between C16 and C30, as well as detected polyaromatic hydrocarbon (PAH) compounds such as anthracene, phenanthrene, fluoranthene and pyrene support the assumption that diesel fuel or high boiling fractions of oil are deposited on the site. Targeted quantitative analysis for selected compounds showed high concentration of substances typically released from man-made products such as plastics, textiles, household and consumer products. Phthalate, an integral component of plastic products, was the dominant compound group in all sediment samples and run-off water samples. Technical nonylphenols (mixture of

  12. Mass Varying Neutrinos in Supernovae

    CERN Document Server

    Rossi-Torres, F; de Holanda, P C; Peres, O L G

    2010-01-01

    We study limits for the mass varying neutrino model, using constrains from supernova neutrinos placed by the r-process condition, $Y_e<0.5$. Also, we use this model in a supernova environment to study the regions of survival probability in the oscillation space parameter ($\\tan^2\\theta$ and $\\Delta m^2_0$), considering the channel $\

  13. Depositional Environment of Mio-Pliocene Siwalik Sedimentary Strata from the Darjeeling Himalayan Foothills, India: A Palynological Approach.

    Directory of Open Access Journals (Sweden)

    Sandip More

    Full Text Available A rich and diverse palynoassemblage recovered from the Churanthi River section (26°53' 59.3" N, 88°34' 17.2" E, Darjeeling foothills Eastern Himalaya, has yielded 87 species assigned to 69 genera. The palynoassemblage is rich in angiosperm taxa (45.63% followed by gymnosperms (0.45%, pteridophytes (18.49% and fungal remains (23.88%. Based on their nearest living relatives, a wet evergreen to semi-evergreen forest under a humid tropical to sub-tropical environment during the Mio-Pliocene age has been suggested. A lot of angiosperms such as Palaeosantalaceaepites, Araliaceoipollenites, Malvacearampollis, Zonocostites, Neocouperipollis, Dicolpopollis, Palmidites, Palmaepollenites, isolated salt glands of mangrove plant leaves (Heliospermopsis and Mediaverrunites type of fungal spores, along with ichnofossils like Planolites, Palaeophycus, Skolithos, Rosselia, Ophiomorpha and Teichichnus associated with rippled mudstone-siltstone suggest an environment strongly influenced by brackish water. Primary sedimentary structures in the associated strata indicate strong wave agitation common in shallow marine setting. Some high elevation components (5.14% such as Alnipollenites, cf. Corylus (Betulaceae, Juglanspollenites, Engelhardtioipollenites (Juglandaceae, Quercoides, Cupuliferoidaepollenites, Lithocarpus, Castanopsis (Fagaceae, Abietineaepollenites (Pinaceae represent hinterland vegetation possibly transported to the prograding deltaic coastline by the rivers. Reworked palynotaxa (Striatopodocarpites sp., Striatites sp., Faunipollenites sp., Circumstriatites sp., Crescentipollenites sp., Cuneatisporites sp., Parasaccites sp., Scheuringipollenites sp., Rhizomaspora sp., Marsupipollenites sp., Lophotriletes sp. of Permian age have also been recorded in the palynoassemblage (11.55% indicating the abundance of Permian Gondwana strata in the source area.

  14. Depositional Environment of Mio-Pliocene Siwalik Sedimentary Strata from the Darjeeling Himalayan Foothills, India: A Palynological Approach.

    Science.gov (United States)

    More, Sandip; Paruya, Dipak Kumar; Taral, Suchana; Chakraborty, Tapan; Bera, Subir

    2016-01-01

    A rich and diverse palynoassemblage recovered from the Churanthi River section (26°53' 59.3" N, 88°34' 17.2" E), Darjeeling foothills Eastern Himalaya, has yielded 87 species assigned to 69 genera. The palynoassemblage is rich in angiosperm taxa (45.63%) followed by gymnosperms (0.45%), pteridophytes (18.49%) and fungal remains (23.88%). Based on their nearest living relatives, a wet evergreen to semi-evergreen forest under a humid tropical to sub-tropical environment during the Mio-Pliocene age has been suggested. A lot of angiosperms such as Palaeosantalaceaepites, Araliaceoipollenites, Malvacearampollis, Zonocostites, Neocouperipollis, Dicolpopollis, Palmidites, Palmaepollenites, isolated salt glands of mangrove plant leaves (Heliospermopsis) and Mediaverrunites type of fungal spores, along with ichnofossils like Planolites, Palaeophycus, Skolithos, Rosselia, Ophiomorpha and Teichichnus associated with rippled mudstone-siltstone suggest an environment strongly influenced by brackish water. Primary sedimentary structures in the associated strata indicate strong wave agitation common in shallow marine setting. Some high elevation components (5.14%) such as Alnipollenites, cf. Corylus (Betulaceae), Juglanspollenites, Engelhardtioipollenites (Juglandaceae), Quercoides, Cupuliferoidaepollenites, Lithocarpus, Castanopsis (Fagaceae), Abietineaepollenites (Pinaceae) represent hinterland vegetation possibly transported to the prograding deltaic coastline by the rivers. Reworked palynotaxa (Striatopodocarpites sp., Striatites sp., Faunipollenites sp., Circumstriatites sp., Crescentipollenites sp., Cuneatisporites sp., Parasaccites sp., Scheuringipollenites sp., Rhizomaspora sp., Marsupipollenites sp., Lophotriletes sp.) of Permian age have also been recorded in the palynoassemblage (11.55%) indicating the abundance of Permian Gondwana strata in the source area.

  15. Reconstruction of the Palaeo-environment of the Alluvial Deposits in the Eastern Free State, South Africa

    Science.gov (United States)

    Evans, M. Y.

    2009-04-01

    Small alluvial fan systems have formed off the hillslopes of the remnant Karoo koppies at Heelbo in the Eastern Free State, South Africa. The landform geometry is a result of complex relationships between climate, lithology, structure and vegetation. This research area, which includes a large mammal mass death site, potentially contains a wealth of palaeo-environmental and specifically palaeoclimatic information. Palaeo-environmental information and proxy records on past climates in southern Africa has traditionally been obtained from a variety of techniques including stable isotope analysis of speleothems, pollen , faunal analyses at archeological sites, animal remains and crater-lake sediments (see references below). However, little information exists in the scientific literature on the use of palaeosols for defining the depositional palaeoenvironments in southern Africa. The aim of this research is to attempt to address the lack of palaeo-environmental information by extracting palaeoclimatic information from the sedimentary processes and the palaeosols at the Heelbo farm that have been extensively exposed through gullying. The sedimentary fans in the area have experienced climatically controlled histories of erosion, sedimentation and pedogenesis. Extreme sedimentation is assumed to have occurred during relatively arid climatic intervals, when decreased vegetation cover provided little surface protection. In contrast pedogenesis occurs during humid intervals when vegetation cover is restored, the land stabilizes and the uppermost gravely sands weather to form soils. A combined approach of both radiocarbon- and luminescence -dating may provide a detailed chronology of these successive hillslope events in order to relate hillslope instability to climatic forcing factors. Preliminary results indicate that at least 3 depositional events are recorded within the large mammal mass death site, which have been confirmed by the radiocarbon dates of 3,610 ±110 in the top

  16. Capillary deposition of advected floating particles

    Science.gov (United States)

    Dressaire, Emilie; Debaisieux, Aymeric; Gregori, Federico

    2016-11-01

    The deposition and aggregation of particles flowing through a confined environment can dramatically hinder the transport of suspensions. Yet, the mechanisms responsible for the deposition of particles in shear flow are not fully understood. Here, we use an experimental model system in which floating particles are advected on the surface of a water channel and deposited on fixed obstacles through attractive capillary effects. By varying the flow rate of the liquid, the wetting properties and size of the particles and obstacles, we can tune the magnitude of the capillary and hydrodynamic forces that determine the probability of deposition and the equilibrium position on the substrate. We show that arrays of obstacles can be designed to efficiently capture the floating particles advected by the flow.

  17. Humid environment stability of low pressure chemical vapor deposited boron doped zinc oxide used as transparent electrodes in thin film silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Steinhauser, Jerome, E-mail: jerome.steinhauser@oerlikon.com [Institute of Microtechnology (IMT), University of Neuchatel, CH-2000 Neuchatel (Switzerland); Meyer, Stefan; Schwab, Marlene; Fay, Sylvie; Ballif, Christophe [Institute of Microtechnology (IMT), University of Neuchatel, CH-2000 Neuchatel (Switzerland); Kroll, U.; Borrello, D. [Oerlikon Solar-Lab, 2000 Neuchatel (Switzerland)

    2011-10-31

    The stability in humid environment of low pressure chemical vapor deposited boron doped zinc oxide (LPCVD ZnO:B) used as transparent conductive oxide in thin film silicon solar cells is investigated. Damp heat treatment (exposure to humid and hot atmosphere) induces a degradation of the electrical properties of unprotected LPCVD ZnO:B layers. By combining analyses of the electrical and optical properties of the films, we are able to attribute this behavior to an increase of electron grain boundary scattering. This is in contrast to the intragrain scattering mechanisms, which are not affected by damp heat exposure. The ZnO stability is enhanced for heavily doped films due to easier tunneling through potential barrier at grain boundaries.

  18. Novel SiO2-deposited CaF2 substrate for vibrational sum-frequency generation (SFG) measurements of chemisorbed monolayers in an aqueous environment.

    Science.gov (United States)

    Padermshoke, Adchara; Konishi, Shouta; Ara, Masato; Tada, Hirokazu; Ishibashi, Taka-Aki

    2012-06-01

    A novel SiO(2)-deposited CaF(2) (SiO(2)/CaF(2)) substrate for measuring vibrational sum-frequency generation (SFG) spectra of silane-based chemisorbed monolayers in aqueous media has been developed. The substrate is suitable for silanization and transparent over a broad range of the infrared (IR) probe. The present work demonstrates the practical application of the SiO(2)/CaF(2) substrate and, to our knowledge, the first SFG spectrum at the solid/water interface of a silanized monolayer observed over the IR fingerprint region (1780-1400 cm(-1)) using a back-side probing geometry. This new substrate can be very useful for SFG studies of various chemisorbed organic molecules, particularly biological compounds, in aqueous environments.

  19. Sedimentary environments and stratigraphy of the carbonate-silicilastic deposits of the Shirgesht Formation: implications for eustasy and local tectonism in the Kalmard Block, Central Iran

    Directory of Open Access Journals (Sweden)

    aram bayetgoll

    2015-10-01

    Formations along the basement Kalmard Fault. In the present study, three stratigraphic sections (NW-SE transects were measured, described and sampled in the Kalmard area. In these sections, detailed considerations have been given on the lithofacies variations; bed geometry and contacts, faunal content, the potential of trace fossils as tools for reconstructing depositional conditions, sedimentary textures and structures, bounding surfaces, vertical trends and stacking patterns and lateral/vertical variations in facies and thicknesses. The observed siliciclastic facies can readily be interpreted using existing shelf sedimentation and shoreline succession models (e.g. Walker and Plint 1992 . Interpretation carbonate facies have been done on the basis the microfacies analysis (200 thin-sections, sedimentary textures and structures and faunal content (Wilson et al. 1975; Flügel 2010 . In final, internal architecture, characteristics of sedimentary facies, the overall stacking pattern and nature of sequence-bounding unconformities have been investigated to evaluate the influence of regional uplift, local tectonics and eustasy on both along-strike variations in sequence architecture and genetic complexity of sequence boundaries.     Discussion, Results and Conclusion   The Lower Ordovician Shirgesht Formation in central Iran is composed of siliciclastic and carbonate rocks deposited in diverse coastal and marine shelf environments (tidal flat, lagoon, shoreface, and offshore-shelf and carbonate ramp. Relying on the facies characteristics and stratal geometries, the siliciclastic succession are divided into five facies associations, FA1 (tidal flat, FA2 (lagoon/washoverfan, FA3 (upper shoreface-foreshore, FA4 (lower to middle shoreface, and FA5 (offshore-shelf.Carbonate succession of this formation based on lithology, sedimentary characteristics and textures divided into four facies belts, FA (tidal flat, FB (lagoon,FC (shoal/barrier island, and FD (open marine. These facies

  20. Geochemical characterization of lower Toarcian source rocks from NW Germany: interpretation of aromatic and saturated hydrocarbons in relation to depositional environment and maturation effects

    Energy Technology Data Exchange (ETDEWEB)

    Radke, M.; Schaefer, R.G. [Institut fuer Erdol und Organische Geochemie, Juelich (Germany); Vriend, S.P. [University of Utrecht (Netherlands). Institute of Earth Sciences

    2001-07-01

    The characterization of crude oils in terms of source rock facies and depositional environment, as well as their maturity and alteration stage, is a crucial element in exploration studies. The present contribution has implications for oil-oil and oil-source rock correlations. In the past, numerous parameters have been used for this purpose most of which are based on the analysis of saturated and aromatic hydrocarbons (including sulphur aromatics) and also on stable isotope signatures and elemental compositions. Recently, molecular indicators based on dibenzothiophene (DBT), phenanthrene (PHE) and their methyl derivatives methyldlbenzothiophene (MDBT) an methylphenanthrene, as well as pristane (PRI) and phytane (PHY), have also been proposed (Hughes et al, 1995). These studies have attempted to infer a crude oil's source rock facies and lithology, and to classify the source rock's depositional environment. In the present study, the above compounds have been quantified by solvent extraction, liquid chromatography and capillary gas chromatography in 98 core samples of the Lower Toarcian Posidonia Shale Formation, a source rock in NW Germany. Most samples cored between depths of 7m and 70 m, came from the Hils Half-Graben in the Lower Saxony Basin. With a few exceptions from on borehole, the samples were unweathered maris or calcareous shales. The rocks contained mainly marine organic matter (Type 1 kerogen), the thermal maturity of which ranged from early mature to postmature (corresponding to 0.48-1.44% mean vitrinite reflectance), therefore encompassing the range over which effective petroleum generation had occurred. We found that the influence of organic matter type and maturity on the molecular distributions of the above compounds were not obvious when interpreted in term of a DBT/PHE vs PRI/PHY diagram. However, Principal Component Analysis (PCA) of our data-set showed that alkylphenanthren concentrations are strongly controlled by maturity, while the

  1. Origins of chromite and magnetite in sedimentary rocks deposited in a shallow water environment in the 3.2 Ga Moodies Group, South Africa

    Science.gov (United States)

    Otake, T.; Sakamoto, Y.; Itoh, S.; Yurimoto, H.; Kakegawa, T.

    2012-12-01

    *Otake, T. totake@eng.hokudai.ac.jp Div. of Sustainable Resources Engineering, Hokkaido Univ., Sapporo, Japan Sakamoto, Y. yu.sakamoto12@gmail.com Dep. of Earth Science, Tohoku Univ., Sendai, Japan Itoh, S. sitoh@ep.sci.hokudai.ac.jp Dep. of Natural History Sciences, Hokkaido Univ., Sapporo, Japan Yurimoto. H. yuri@ep.sci.hokudai.ac.jp Dep. of Natural History Sciences, Hokkaido Univ., Sapporo, Japan Kakegawa, T. kakegawa@m.tohoku.ac.jp Dep. of Earth Science, Tohoku Univ., Sendai, Japan Geochemical data from ferruginous chemical sedimentary rocks (e.g., Banded Iron Formation: BIF) have been used to reconstruct the surface environments of early Earth. However, only a few studies have investigated the geochemical characteristics of BIFs deposited in a shallow water environment during the Archean, which may have differed from those deposited in a deep water environment. Therefore, we investigated geological, petrographic and geochemical characteristics of ferruginous rocks deposited in a shallow water environment in the Moodies group, in the Barberton Greenstone Belt, South Africa. We obtained ferruginous rock samples in the Moodies group from both an outcrop and underground gold mine, and compared the characteristics of these samples. The 70 sedimentary rock samples were divided into groups based on the dominant Fe minerals they contain: Hematite-rich jaspilite (HM group), Magnetite-rich iron formation/shale/sandstone (MT group), and Siderite-rich sandstone (SD group). Samples in the HM group are predominantly composed of fine-grained quartz (< 20 μm) and hematite (< 5 μm), which are interpreted to be chemical precipitates. Samples in the MT group contain quartz, magnetite, siderite, ankerite, chlorite, biotite and chromite. The grain size of magnetite is much larger (20-150 μm) than that of hematite in the HM group. The magnetite is interpreted as a secondary mineral transformed from hematite during early diagenesis. Results of in situ oxygen isotope analysis by

  2. Landscapes, depositional environments and human occupation at Middle Paleolithic open-air sites in the southern Levant, with new insights from Nesher Ramla, Israel

    Science.gov (United States)

    Zaidner, Yossi; Frumkin, Amos; Friesem, David; Tsatskin, Alexander; Shahack-Gross, Ruth

    2016-04-01

    Middle Paleolithic human occupation in the Levant (250-50 ka ago) has been recorded in roofed (cave and rockshelter) and open-air sites. Research at these different types of sites yielded different perspectives on the Middle Paleolithic human behavior and evolution. Until recently, open-air Middle Paleolithic sites in the Levant were found in three major sedimentary environments: fluvial, lake-margin and spring. Here we describe a unique depositional environment and formation processes at the recently discovered open-air site of Nesher Ramla (Israel) and discuss their contribution to understanding site formation processes in open-air sites in the Levant. The site is 8-m-thick Middle Paleolithic sequence (OSL dated to 170-80 ka) that is located in a karst sinkhole formed by gravitational deformation and sagging into underground voids. The sedimentary sequence was shaped by gravitational collapse, cyclic colluviation of soil and gravel into the depression, waterlogging, in situ pedogenesis and human occupation. Original bedding and combustion features are well-preserved in the Lower archaeological sequence, a rare occurrence in comparison to other open-air archaeological sites. This phenomenon coincides with episodes of fast sedimentation/burial, which also allowed better preservation of microscopic remains such as ash. The Upper archaeological sequence does not exhibit bedding or preservation of ash, despite presence of heat-affected lithic artifacts, which makes it similar to other open-air sites in the Levant. We suggest that rate of burial is the major factor that caused the difference between the Upper and Lower sequences. The differences in the burial rate may be connected to environmental and vegetation changes at the end of MIS 6. We also identified an interplay between sediment in-wash and density of human activity remains, i.e. during episodes of low natural sediment input the density of artifacts is higher relative to episodes with high rate of sediment in

  3. Enhanced photovoltaic performance and time varied controllable growth of a CuS nanoplatelet structured thin film and its application as an efficient counter electrode for quantum dot-sensitized solar cells via a cost-effective chemical bath deposition.

    Science.gov (United States)

    Thulasi-Varma, Chebrolu Venkata; Rao, S Srinivasa; Kumar, Challa Shesha Sai Pavan; Gopi, Chandu V V M; Durga, I Kanaka; Kim, Soo-Kyoung; Punnoose, Dinah; Kim, Hee-Je

    2015-11-28

    For the first time we report a simple synthetic strategy to prepare copper sulfide counter electrodes on fluorine-doped tin oxide (FTO) substrates using the inexpensive chemical bath deposition method in the presence of hydrochloric acid (HCl) at different deposition times. CuS nanoplatelet structures were uniformly grown on the FTO substrate with a good dispersion and optimized conditions. The growth process of the CuS nanoplatelets can be controlled by changing the deposition time in the presence of HCl. HCl acts as a complexing agent as well as improving S(2-) concentration against S atoms in this one-step preparation. The photovoltaic performance was significantly improved in terms of the power conversion efficiency (PCE), short-circuit density (J(sc)), open-circuit voltage (V(oc)), and the fill factor (FF). The optimized deposition time of CuS 60 min resulted in a higher PCE of 4.06%, J(sc) of 12.92 mA cm(-2), V(oc) of 0.60 V, and a FF of 0.52 compared to CuS 50 min, CuS 70 min, and a Pt CE. The superior performance of the 60 min sample is due to the greater electrocatalytic activity and low charge transfer resistance at the interface of the CE and the polysulfide electrolyte. The concentration of Cu/S also had an important role in the formation of the CuS nanoplatelet structures. The optical bandgaps for the CuS with different morphologies were measured to be in the range of 1.98-2.28 eV. This improved photovoltaic performance is mainly attributed to the greater number of active reaction sites created by the CuS layer on the FTO substrate, which results large specific surface, superior electrical conductivity, low charge transfer resistance, and faster electron transport in the presence of HCl. Cyclic voltammetry, electrochemical impedance spectroscopy and Tafel-polarization measurements were used to investigate the electrocatalytic activity of the CuS and Pt CEs. This synthetic procedure not only provides high electrocatalytic activity for QDSSCs but could

  4. Spectral and chemical characterization of jarosite in a palaeolacustrine depositional environment in Warkalli Formation in Kerala, South India and its implications

    Science.gov (United States)

    Singh, Mahima; Rajesh, V. J.; Sajinkumar, K. S.; Sajeev, K.; Kumar, S. N.

    2016-11-01

    Coastal cliffs fringing the Arabian Sea near Varkala exhibits the Warkalli Formation of the Tertiary sequence of Kerala, South India, with well-marked occurrence of jarosite associated with other hydrous mineral phases of phyllosilicate family in a palaeo-lacustrine depositional environment. Sandy phyllosilicates dominate the mineral assemblage, but jarosite occurs as a prominent secondary phase formed during acid-sulphate alteration of iron sulphide in this area. Here, we discuss about the potentiality of spectroscopic techniques to identify the possible mineral phases in the collected samples. The samples from the coastal cliffs have been characterized by hyperspectral analysis (VIS-NIR-SWIR), X-ray Diffraction (XRD), Fourier Transform Infra-red Reflectance (FTIR), Electron Probe Microanalysis (EPMA) and Laser Raman spectroscopy. The spectral and chemical analyses have confirmed the jarosite as natrojarosite and phyllosilicate as kaolinite. Other accessory phases have also been identified through XRD. FTIR spectroscopy has played a major role in identifying the major hydrous bonds between the minerals. VIS-NIR-SWIR spectra show several optimum spectral features at 910 nm, 1470 nm, 1849-1864 nm (in the form of a doublet), 1940 nm and 2270 nm, which could be utilised to locate jarosite in the remotely-sensed data. X-ray diffraction peaks helped in the identification of maximum number of minerals (kaolinite, smectite, quartz, feldspar, pyrite, marcasite and hematite) and the variation in jarosite content in the samples. We propose the formation of jarosite in the region by a seasonal, local and temporary development of acidic conditions. Abundance of organic matter in a fluvio-lacustrine environment has developed anaerobic conditions by removing available oxygen through decomposition of organic matter containing sulphur compounds. The sulphur thus liberated combines with hydrogen from water to develop acidic conditions and resulted in the formation of jarosite. The

  5. Dry deposition of gaseous elemental mercury to plants and soils using mercury stable isotopes in a controlled environment

    Science.gov (United States)

    Rutter, Andrew P.; Schauer, James J.; Shafer, Martin M.; Creswell, Joel E.; Olson, Michael R.; Robinson, Michael; Collins, Ryan M.; Parman, Andrew M.; Katzman, Tanya L.; Mallek, Justin L.

    2011-02-01

    Uptake of gaseous elemental mercury (Hg 0(g)) by three plant species and two soil types was measured using mercury vapor enriched in the 198 isotope ( 198Hg 0(g)). The plant species and soil types were: White Ash ( Fraxinus Americana; WA); White Spruce ( Picea Glauca; WS); Kentucky Bluegrass ( Poa Partensis; KYBG); Plano Silt Loam (4% organic matter; PSL); and Plainfield Sand/Sparta Loamy Sand (1.25-1.5% organic matter: PS). The plants and soils were exposed to isotopically enriched Hg 0(g) in a 19 m 3 controlled environment room for 7 days under optimal plant growth conditions (20 °C, 140 Wm -2 between 300 nm and 700 nm; 70% RH) and atmospherically relevant Hg 0(g) concentrations. Mercury was recovered from the samples using acidic digestions and surface leaches, and then analyzed for enrichments in 198Hg by ICPMS. The method was sensitivity enough that statistically significant enrichments in 198Hg were measured in the plant foliage at the end of Day 1. Whole leaf digestions and surface-selective leaches revealed that accumulative uptake was predominantly to the interior of the leaf under the conditions studied. Uptake fluxes for WA increased between the first and third days and remained constant thereafter (WA; Day 1 = 7 ± 2 × 10 -5 ng m -2 s -1; Days 3-7 = 1.3 ± 0.1 × 10 -4 ng m -2 s -1; where m 2 refers to one sided leaf area). KYBG demonstrated similar behavior although no Day 3 measurement was available (Day 1 = 7.5 ± 0.5 × 10 -5 ng m -2 s -1; Day 7 = 1.2 ± 0.1 × 10 -4 ng m -2 s -1). Fluxes to White Spruce were lower, with little difference between Days 1 and 3 followed by a decrease at Day 7 (WS; Days 1-3 = 5 ± 2 × 10 -5 ng m -2 s -1; Day 7 = 2.4 ± 0.2 × 10 -5 ng m -2 s -1). Uptake of Hg to soils was below the method detection limit for those media (PSL = 3 × 10 -2 ng m -2 s -1; PS = 3 × 10 -3 ng m -2 s -1) over the 7 day study period. Foliar resistances calculated for each species compared well to previous studies.

  6. Evidence for biological activity in mineralization of secondary sulphate deposits in a basaltic environment: implications for the search for life in the Martian subsurface

    Energy Technology Data Exchange (ETDEWEB)

    C. Doc Richardson; Nancy W. Hinman; Jill R. Scott

    2013-10-01

    Evidence of microbial activity associated with mineralization of secondary Na-sulphate minerals (thenardite, mirabilite) in the basaltic subsurface of Craters of the Moon National Monument (COM), Idaho were examined by scanning electron microscopy, X-ray diffraction, laser desorption Fourier transform ion cyclotron resonance mass spectrometry (LD-FTICR-MS), Fourier transform infrared spectroscopy (FTIR) and isotope ratio mass spectrometry. Peaks suggestive of bio/organic compounds were observed in the secondary Na-sulphate deposits by LD-FTICR-MS. FTIR provided additional evidence for the presence of bio/organic compounds. Sulphur fractionation was explored to assist in determining if microbes may play a role in oxidizing sulphur. The presence of bio/organic compounds associated with Na-sulphate deposits, along with the necessity of oxidizing reduced sulphur to sulphate, suggests that biological activity may be involved in the formation of these secondary minerals. The secondary Na-sulphate minerals probably form from the overlying basalt through leached sodium ions and sulphate ions produced by bio-oxidation of Fe-sulphide minerals. Since the COM basalts are one of the most comparable terrestrial analogues for their Martian counterparts, the occurrence of biological activity in the formation of sulphate minerals at COM has direct implications for the search for life on Mars. In addition, the presence of caves on Mars suggests the importance of these environments as possible locations for growth and preservation of microbial activity. Therefore, understanding the physiochemical pathways of abiotic and biotic mineralization in the COM subsurface and similar basaltic settings has direct implications for the search for extinct or extant life on Mars.

  7. Sedimentary environments and stratigraphy of the carbonate-silicilastic deposits of the Shirgesht Formation: implications for eustasy and local tectonism in the Kalmard Block, Central Iran

    Directory of Open Access Journals (Sweden)

    reza Mousavi-Harami

    2015-09-01

    Rahdar (Devonian Formations along the basement Kalmard Fault. In the present study, three stratigraphic sections (NW-SE transects were measured, described and sampled in the Kalmard area. In these sections, detailed considerations have been given on the lithofacies variations bed geometry and contacts, faunal content, the potential of trace fossils as tools for reconstructing depositional conditions, sedimentary textures and structures, bounding surfaces, vertical trends and stacking patterns and lateral/vertical variations in facies and thicknesses. The observed siliciclastic facies can readily be interpreted using existing shelf sedimentation and shoreline succession models (e.g. Walker and Plint 1992 . Interpretation carbonate facies have been done on the basis the microfacies analysis (200 thin-sections, sedimentary textures and structures and faunal content (Wilson et al. 1975 Flügel 2010 . In final, internal architecture, characteristics of sedimentary facies, the overall stacking pattern and nature of sequence-bounding unconformities have been investigated to evaluate the influence of regional uplift, local tectonics and eustasy on both along-strike variations in sequence architecture and genetic complexity of sequence boundaries.     Discussion, Results and Conclusion   The Lower Ordovician Shirgesht Formation in central Iran is composed of siliciclastic and carbonate rocks deposited in diverse coastal and marine shelf environments (tidal flat, lagoon, shoreface, and offshore-shelf and carbonate ramp. Relying on the facies characteristics and stratal geometries, the siliciclastic succession are divided into five facies associations, FA1 (tidal flat, FA2 (lagoon/washoverfan, FA3 (upper shoreface-foreshore, FA4 (lower to middle shoreface, and FA5 (offshore-shelf.Carbonate succession of this formation based on lithology, sedimentary characteristics and textures divided into four facies belts, FA (tidal flat, FB (lagoon,FC (shoal/barrier island, and FD

  8. Outcrop analogue study of Permocarboniferous geothermal sandstone reservoir formations (northern Upper Rhine Graben, Germany): impact of mineral content, depositional environment and diagenesis on petrophysical properties

    Science.gov (United States)

    Aretz, Achim; Bär, Kristian; Götz, Annette E.; Sass, Ingo

    2016-07-01

    The Permocarboniferous siliciclastic formations represent the largest hydrothermal reservoir in the northern Upper Rhine Graben in SW Germany and have so far been investigated in large-scale studies only. The Cenozoic Upper Rhine Graben crosses the Permocarboniferous Saar-Nahe Basin, a Variscan intramontane molasse basin. Due to the subsidence in this graben structure, the top of the up to 2-km-thick Permocarboniferous is located at a depth of 600-2900 m and is overlain by Tertiary and Quaternary sediments. At this depth, the reservoir temperatures exceed 150 °C, which are sufficient for geothermal electricity generation with binary power plants. To further assess the potential of this geothermal reservoir, detailed information on thermophysical and hydraulic properties of the different lithostratigraphical units and their depositional environment is essential. Here, we present an integrated study of outcrop analogues and drill core material. In total, 850 outcrop samples were analyzed, measuring porosity, permeability, thermal conductivity and thermal diffusivity. Furthermore, 62 plugs were taken from drillings that encountered or intersected the Permocarboniferous at depths between 1800 and 2900 m. Petrographic analysis of 155 thin sections of outcrop samples and samples taken from reservoir depth was conducted to quantify the mineral composition, sorting and rounding of grains and the kind of cementation. Its influence on porosity, permeability, the degree of compaction and illitization was quantified. Three parameters influencing the reservoir properties of the Permocarboniferous were detected. The strongest and most destructive influence on reservoir quality is related to late diagenetic processes. An illitic and kaolinitic cementation and impregnation of bitumina document CO2- and CH4-rich acidic pore water conditions, which are interpreted as fluids that migrated along a hydraulic contact from an underlying Carboniferous hydrocarbon source rock. Migrating

  9. 非采暖空调环境下人体热反应的时变特征分析%Time-varying characteristics of people's responses to thermal comfort in free-running environment

    Institute of Scientific and Technical Information of China (English)

    李百战; 雷丹妮; 刘红; 谈美兰

    2012-01-01

    In order to study the time-varying characteristics of people's responses to thermal comfort in free-running environment, a physiological experiment was conducted in a free-running building in four seasons, and the subjects were all healthy college students. Sensory nerve conduction velocity (vsc), skin temperature of measuring point (tskin) and thermal environmental parameters were tested; the subjective thermal sensation questionnaires were filled out by subjects simultaneously. The results show that in a certain season, vsc, tskin and people's whole thermal sensation votes (TSV) have the same changing trend with time; in winter and transition seasons (Spring and Autumn), vsc and tskin show a declining trend to be a stable value, but with largest decrement in winter. While in summer, vsc and tskin only fluctuate within a narrow range. For TSV and local thermal sensation votes (TSVlocal), they all have significant time-varying characteristics in winter and fluctuate with comfort range in summer and transition seasons. This demonstrates that the retention time is also an important factor that affects human thermal comfort from both physiological and psychological aspects especially in cold environment. The results provide a better design to control the indoor thermal environment for the occupants' health and comfort, and determine the measuring time of physical parameters on the basis of the time needed for stability.%为了分析非采暖空调环境下人体热反应的时变特征,以在校健康大学生为受试对象,在全年4个季节里开展人体热舒适生理实验测试,记录主要热环境参数,研究人体客观生理指标感觉神经传导速度(vSC)、测点皮肤温度(tskin)、整体热感觉投票(TSV)以及局部热感觉投票(TSVlocal)随停留时间变化的响应过程.研究结果表明:在同一季节里,vSC,tskin和TSV的时变特征具有一致性;在冬季和过渡季节(春季和秋季),vSC和tskin随停留时间的延长呈下

  10. Lithostratigraphic description, sedimentological characteristics and depositional environments of rocks penetrated by Illela borehole, Sokoto Basin, NW Nigeria: A connection between Gulf of Guinea Basins

    Science.gov (United States)

    Toyin, A.; Adekeye, O. A.; Bale, R. B.; Sanni, Z. J.; Jimoh, O. A.

    2016-09-01

    The basal unit of the succession in the Illela borehole belongs to the Dange Formation comprising thick calcareous and variably coloured dark-greyish shale of 36.30 m thick which is overlain by a 31.44 m thick limestone of Kalambaina Formation with 1.7 m thick shaly-limestone inclusive. The uppermost part of the section belongs to the Gwandu Formation which has intercalation of silty-clay, muddy siltstones with well lithified ironstone capping the borehole section. The limestone/carbonate microfacie as deduced from their salient lithologic, sedimentologic and paleontologic features are comparable to standard microfacie (SMF) types 9 and 10, i.e. bioclastic wackestone/bioclastic micrite and packstone-wackestone respectively. Diagenetically, syndepositional and early diagenesis have taken place particularly cementation and replacement in the carbonate rocks and these have greatly affected the reservoir potential negatively. The matrix/grain relationships indicate a shallow marine environment of deposition. The borehole section is delineated into upper foraminifera and lower ostracod biostratigraphic units as no formal biostratigraphic zonation could be attempted due to low diversity of both benthic foraminifera, marine ostracods and the absence of planktonic foraminifera. The similarity of the ostracod assemblages between this study area, Illela borehole, West Africa, North Africa (Libya), Mali and Niger Republic) and South-Western Nigeria (West Africa) suggests that a marine connection exists between the Gulf of Guinea and the Sokoto Basin via the area occupied by the River Niger during the Paleocene.

  11. Depositional environments of the Hart coal zone (Paleocene), Willow Bunch Coalfield, southern Saskatchewan, Canada from petrographic, palynological, paleobotanical, mineral and trace element studies

    Energy Technology Data Exchange (ETDEWEB)

    Potter, J.; Beaton, A.P.; McDougall, W.J.; Nambudiri, E.M.V.; Vigrass, L.W. (University of Regina, SK (Canada). Energy Research Unit)

    1991-12-01

    Coal petrology, palynology, paleobotany and mineralogy of the Hart coal indicate deposition under wet, warm-temperate to subtropical climatic conditions in low-lying backswamps with fluvial channels and locally ponded areas. The coal is dominated by mixed xylitic/attrital lithotypes and by huminite macerals with secondary inertinite macerals and minor liptinite macerals. Good correlation exists between lithotypes and maceral composition. Local and vertical variations in proportions of huminites and inertinites reflect frequent fluctuations in water levels, periodic flooding, desiccation and burning of the peat. Swamps were dominated by {ital Glyptostrobus-Taxodium} forest with {ital Betula-Myrica-Alnus} communities and, locally {ital Laevigatosporites}, which are the dominant contributors to the xylite-rich lithotypes. Attrital lithotypes with abundant {ital Pandanus}, {ital Typha} and {ital Azolla} are consistent with wetter areas of a fluvial environment, including ponds and channels. Trace elements Cr, Cu, Mo, Ni, Si, Ti, U, Se, V, W, K and Th, typically associated with syngenetic minerals kaolinite, calcite and quartz, may have a volcanic source. High concentrations of Na, Ba and Ca found in organic complexes are of secondary origin and probably originate in deep source brines rather than marine surface waters. 55 refs., 11 figs., 5 tabs.

  12. The Jurassic of Denmark and Greenland: Early and Middle Jurassic mires of Bornholm and the Fennoscandian Border Zone: a comparison of depositional environments and vegetation

    Directory of Open Access Journals (Sweden)

    Koppelhus, Eva B.

    2003-10-01

    resund area, and up to 19 000 years on Bornholm. The combination of the inland position of the mires, a seasonal climate, and on occasion a peat surface above groundwater level caused temporary oxidation of the peat surfaces and formation of inertinite-rich coals. The spore and pollen assemblages from coal seams and interbedded siliciclastic deposits indicate that the dominant plant groups in both the Early and Middle Jurassic mires were ferns and gymnosperms. However, significant floral differences are evident. In the Lower Jurassic coals, the palynology testifies to a vegetation rich in cycadophytes and coniferophytes (Taxodiaceae family whereas club mosses were of lesser importance. Conversely, in the Middle Jurassic coals, the palynology indicates an absence of cycadophytes, a minor proportion of coniferophytes (Taxodiaceaeand a significant proportion of club mosses. These variations are probably related to adaptation by different plants to varying environmental conditions, in particular of hydrological character.

  13. Bauxite Deposits in China

    Institute of Scientific and Technical Information of China (English)

    杨化洲

    1989-01-01

    Bauxite deposits in China,rangin in age from Late Paleozoic to Cenozoic ,are distributed mainly in Shanxi,Shandong Henan,Guizhou,Guangxi and Yunnan.Based on stratigraphic relations they can be clas-sified as 6 types:inter-system marine,inter-system continental,intra-system marine,intra-system continent-tal,weathering lateritic and weathering accumulation types.But in terms of depositional environments,only four types are distinguished,I.e.the marine deposits,continental deposits,lateritic deposits and weath-ering-accumulation deposits.These deposits have been formed in two steps:firstly,the depression of paraplatform or front basin margins in paleocontinents and secondly,the development of littoral-lagoons on the eroded surface of karstified carbonate bedrocks.The aluminum may have been derived from the carbonate rocks with which the ores are associated,or from adjacent aluminosilicate rocks.

  14. Organic geochemical characteristics of the Lower Cretaceous Abu Gabra Formation in the Great Moga oilfield, Muglad Basin, Sudan: Implications for depositional environment and oil-generation potential

    Science.gov (United States)

    Makeen, Yousif M.; Abdullah, Wan Hasiah; Hakimi, Mohammed Hail; Elhassan, Osman M. A.

    2015-03-01

    Organic-rich sediments within the Abu Gabra Formation from three wells in the Great Moga oilfield were analyzed using organic geochemistry and organic petrology. The analyzed samples generally contain more than 2.0 wt.% TOC and have a very good to excellent hydrocarbon generative potential. This is supported by high bitumen extract and hydrocarbon (HCs) yields with values exceeding 4000 and 2000 ppm, respectively. The Abu Gabra also have moderate to high hydrogen index (HI) values of 287-865 mg HC/g TOC and large amounts of amorphous organic matter and alginite, consistent with oil-prone Types I and Type II kerogen. Vitrinite reflectance (0.59-0.72) %Ro and pyrolysis Tmax (430-438 °C) indicate an early oil window stage. This is supported by bitumen/TOC ratios (0.04-0.09) and biomarker thermal maturity parameters with equilibrium C32 homohopane 22S/(22S + 22R) ratios (0.50-58), moretane/hopane (0.11-018) and C29ββ/(ββ + αα) (0.53-0.73) and 20S/(20S + 20R) ratios (0.26-0.48). The biomarkers are characterized by a dominance of low to medium molecular weight n-alkane compounds with significant waxy alkanes (n-C25-n-C34), moderately high Pr/Ph ratios (1.17-2.51), high abundance of C27 regular steranes, high C27/C29 regular sterane ratios, the presence of tricyclic terpanes and relatively low sterane/hopane ratios. These data indicate that the organic-rich sediments of the Abu Gabra Formation contain a mixture of aquatic (algal and bacterial) and terrigenous organic matter, deposited in a lacustrine environment and preserved under suboxic conditions.

  15. 我国矿山地质环境治理恢复保证金制度的法律思考%Legal conception of the governance and restoration deposit system of mine geological environment in China

    Institute of Scientific and Technical Information of China (English)

    张维宸

    2011-01-01

    The geological environment problems of mine in China is even sharper than before, so the management of mine geological environment is urgent. The governance and restoration deposit of mine geological environment can change the situation of high management payment and low illegal cost. It is proposed that speeding up the legislation on the governance and restoration deposit of mine geological environment, reasonable measuring the ecological compensation standard of the governance and restoration deposit amount of mine geological environment, innovating the return form of the governance and restoration deposit of mine geological environment, establishing and improving the compensation mechanism of geological environment damage on mine, strictly implementing the geological environment plan of mine and the assessment system of environmental impact, strictly carrying out the protection system of mine geological environment, as well as strengthening public monitoring on the governance and restoration of mine geological environment.%我国矿山地质环境问题日益突出,对矿山地质环境进行治理已是当务之急.矿山地质环境治理恢复保证金,可以改变传统的矿山环境管理中管理成本高、违法成本低的局面.建议加快矿山地质环境治理恢复保证金制度的立法工作,合理测算矿山地质环境治理恢复保证金数额的生态补偿标准,创新矿山地质环境恢复保证金返还形式,建立健全矿山地质环境损毁补偿赔付机制,严格矿山地质环境规划和环境影响评价制度,实行更加严格的矿山地质环境保护制度,加强公众监督矿山地质环境治理恢复力度.

  16. Geological tectonic settings, depositional environments and ore-hosting rock assemblages for mineral deposits model with universality%矿床类型模型的地质构造背景、成矿环境和容矿岩石组合

    Institute of Scientific and Technical Information of China (English)

    裴荣富; 梅燕雄; 瞿泓滢; 王浩琳

    2013-01-01

    Different mineral deposits have different characteristic features, just like the fact that different people have different ringer prints. Based on the Chinese philosophic idea "white horse is a horse but not a horse (class)", this paper proposes a deepening study of the integrated geological characteristics of the same types or similar groups of mineral deposits model with universality. On such a basis, the mineral deposits model with universality (horse class) will contain the kind of deposits with speciality (white horse) and increase its generality in correlation with unknown mineral deposits. Secondly, in this paper, the research work of mineral deposits model is systematically summarized and a new idea of metallogenic series is put forward for establishing the mineral deposits model with universality. Considering the existence of various mineral deposits in the geological setting, the authors integrate the geological tectonic settings, depositional environments and ore-hosting rock assemblages to formulate "a classification of mineral deposits model of China" and 74 models suitable for various depositional environments to be created (see table 1). On such a basis, we can find any deposits model from corresponding geological setting in the classification; in contrast, a certain mineral deposits model can also reflect the depositional environment in which the deposits occurred.%每一矿床模型类似人们“指纹”各自不同.根据中国哲学的“白马是马而非马(类)”的概念,本文提出应深入研究同一类的矿床总体特征的普适性矿床模型.据此,普适性矿床模型(马类)将包括该类矿床中的矿床(白马),从而增强其对未知矿床比对的整体性.其次,本文又对矿床普适性模型提出成矿系列的新概念.即按各类矿床产出的不同环境,作者等根据一定地质构造背景、一定成矿环境和一定容矿岩石组合提出“中国矿床普适性模型分类”和与

  17. A Simple Analysis of Deposition Environment of Middle Cainozoic Era in Jian Basin%中、新生代吉安盆地沉积环境浅析

    Institute of Scientific and Technical Information of China (English)

    杨永革

    2000-01-01

    Apply deposit physics and chemistry biologic parameter to analysis the deposition enviroment in Jian basin,outstanding results are gained, and some advise are a1larnulated for the analyse of depositiou enviroment of middle caino-zoic era. Based on the describtion of deposition environment in .lian basin. paleobio and earth petrochemistry. The paleo-climet and paleogeography are emphatically discussed.%运用沉积物物理、化学、生物参数,分析吉安盆地的沉积环境,取得了显著效果,为古沉积环境分析积累了经验。在阐述吉安盆地沉积相、古生物及岩石地球化学的基础上,着重对古气候、古地理进行了探讨。

  18. NONMETALS DEPOSITS

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    <正>20111761 Chen Hua(115 Geological Party,Guizhou Bureau of Geology and Mineral Exploration & Development,Guiyang 551400,China);Deng Chao Analysis on the Metallogenic Environment of Maochang Bauxite in Guizhou Province(Guizhou Geology,ISSN1000-5943,CN52-1059/P,27(3),2010,p.198-201,2 illus.,1 table,8 refs.)Key words:bauxite deposit,Guizhou Province By long time physical and chemical process,the carbonate rock after Central Guizhou uplidft,becomes red clay,after further weathering,the red clay decomposed into the oxide,hydroxide of Al and Fe,in the dissolution hole and depression,it concentrates primary fragmentary tight and earthy karst bauxite ore.Because the variation of landform,it decomposes and cracks again,affords the material source

  19. The impact of atmospheric dust deposition and trace elements levels on the villages surrounding the former mining areas in a semi-arid environment (SE Spain)

    Science.gov (United States)

    Sánchez Bisquert, David; Matías Peñas Castejón, José; García Fernández, Gregorio

    2017-03-01

    It is understood that particulate matter in the atmosphere from metallic mining waste has adverse health effects on populations living nearby. Atmospheric deposition is a process connecting the mining wasteswith nearby ecosystems. Unfortunately, very limited information is available about atmospheric deposition surrounding rural metallic mining areas. This article will focus on the deposition from mining areas, combined with its impact on nearby rural built areas and populations. Particle samples were collected between June 2011 and March 2013. They were collected according to Spanish legislation in ten specialised dust collectors. They were located near populations close to a former Mediterranean mining area, plus a control, to assess the impact of mining waste on these villages. This article and its results have been made through an analysis of atmospheric deposition of these trace elements (Mn, Zn, As, Cd and Pb). It also includes an analysis of total dust flux. Within this analysis it has considered the spatial variations of atmospheric deposition flux in these locations. The average annual level of total bulk deposition registered was 42.0 g m-2 per year. This was higher than most of the areas affected by a Mediterranean climate or in semi-arid conditions around the world. Regarding the overall analysis of trace elements, the annual bulk deposition fluxes of total Zn far exceeded the values of other areas. While Mn, Cd and Pb showed similar or lower values, and in part much lower than those described in other Mediterranean mining areas. This study confirmed some spatial variability of dust and trace elements, contained within the atmospheric deposition. From both an environmental and a public health perspective, environmental managers must take into account the cumulative effect of the deposition of trace elements on the soil and air quality around and within the villages surrounding metallic mining areas.

  20. Mineral deposits in western Saudi Arabia; a preliminary report

    Science.gov (United States)

    Roberts, Ralph Jackson; Greenwood, William R.; Worl, Ronald G.; Dodge, F.C.W.; Kiilsgaard, Thor H.

    1975-01-01

    Mineral deposits in Saudi Arabia include a variety of deposits which were formed in many geologic environments. These include magmatic and late magmatic deposits in igneous masses, contact metamorphic deposits along the margins of igneous bodies, and stratiform sulfide deposits and veins. Notable deposits of sedimentary origin include deposits of iron oxides and phosphate.

  1. Transparent heavy minerals in the coastal sediments of south Maharashtra and their significance in delineating source and environment of transportation and deposition

    Digital Repository Service at National Institute of Oceanography (India)

    Mislankar, P.G.; Gujar, A.R.; Ambre, N.V.

    of transportation and deposition. 16 transparent minerals have been identified which represent three different mineral assemblage viz. (1) tourmaline, amphibole, epidote and pyroxene (2) zircon, rutile and titanite (3) staurolite kynaite garnet and olivine...

  2. Fluorosis varied treatment options

    OpenAIRE

    Sherwood I

    2010-01-01

    Fluorosis has been reported way back in 1901. The treatment options for fluorosis are varied depending upon individual cases. This article comes from Madurai in India where its surrounding towns are fluorosis-prone zones. The purpose of this article is to report various treatment options available for dental fluorosis; this is the first time that complete full mouth rehabilitation for dental fluorosis is being reported. This article also dwells on the need for the dentists to be aware of thei...

  3. Unraveling signatures of biogeochemical processes and the depositional setting in the molecular composition of pore water DOM across different marine environments

    Science.gov (United States)

    Schmidt, Frauke; Koch, Boris P.; Goldhammer, Tobias; Elvert, Marcus; Witt, Matthias; Lin, Yu-Shih; Wendt, Jenny; Zabel, Matthias; Heuer, Verena B.; Hinrichs, Kai-Uwe

    2017-06-01

    Dissolved organic matter (DOM) in marine sediment pore waters derives largely from decomposition of particulate organic matter and its composition is influenced by various biogeochemical and oceanographic processes in yet undetermined ways. Here, we determine the molecular inventory of pore water DOM in marine sediments of contrasting depositional regimes with ultrahigh-resolution mass spectrometry and complementary bulk chemical analyses in order to elucidate the factors that shape DOM composition. Our sample sets from the Mediterranean, Marmara and Black Seas covered different sediment depths, ages and a range of marine environments with different (i) organic matter sources, (ii) balances of organic matter production and preservation, and (iii) geochemical conditions in sediment and water column including anoxic, sulfidic and hypersaline conditions. Pore water DOM had a higher molecular formula richness than overlying water with up to 11,295 vs. 2114 different molecular formulas in the mass range of 299-600 Da and covered a broader range of element ratios (H/C = 0.35-2.19, O/C = 0.03-1.19 vs. H/C = 0.56-2.13, O/C = 0.15-1.14). Formula richness was independent of concentrations of DOC and TOC. Near-surface pore water DOM was more similar to water column DOM than to deep pore water DOM from the same core with respect to formula richness and the molecular composition, suggesting exchange at the sediment-water interface. The DOM composition in the deeper sediments was controlled by organic matter source, selective decomposition of specific DOM fractions and early diagenetic molecule transformations. Compounds in pelagic sediment pore waters were predominantly highly unsaturated and N-bearing formulas, whereas oxygen-rich CHO-formulas and aromatic compounds were more abundant in pore water DOM from terrigenous sediments. The increase of S-bearing molecular formulas in the water column and pore waters of the Black Sea and the Mediterranean Discovery Basin was

  4. Fluorosis varied treatment options

    Directory of Open Access Journals (Sweden)

    Sherwood I

    2010-01-01

    Full Text Available Fluorosis has been reported way back in 1901. The treatment options for fluorosis are varied depending upon individual cases. This article comes from Madurai in India where its surrounding towns are fluorosis-prone zones. The purpose of this article is to report various treatment options available for dental fluorosis; this is the first time that complete full mouth rehabilitation for dental fluorosis is being reported. This article also dwells on the need for the dentists to be aware of their local indigenous pathologies to treat it in a better manner.

  5. Tsunami Deposit Data Base

    Science.gov (United States)

    Keating, B. H.; Wanink, M.

    2007-05-01

    A digital database has been established describing tsunami deposits around the world (3 phases; 15 months). The projects involved the review and tabulation of data derived from books, catalogs, journals, preprints, citations and abstracts (currently 1000 references), into a database designed to provide a comprehensive review of the types of tsunami deposits, their geographic distribution and location, sedimentary characteristics, fossil content, age, preservation, run-up, wave height and inundation observations, etc. (34 parameters). The tsunami occurrences can be divided into many subjects, e.g., Volcanogenic (N=375), Seismites (N=49), Co-seismic (N=258), K/T Boundary Impact-triggered debris flows (N=97), Landslides (N=43), etc. Numerous publications compare tsunami deposits to storm deposits (N=38), or analyze the origin of megaboulders (N=22). Tsunami deposits occur throughout geologic time (Pre-Cambrian to present day), and because of plate tectonics, they occur along plate margins (primarily subduction zones) as well as interior to plates. In addition, they occur in epi-continental seas, fjords, etc. Few publications describe depositional processes. Deposits generated by tsunamis occur in multiple environments such as the marine, fresh water, and subaerial. Common characteristics of tsunami deposits include: 1) Deposition of thin sand sheets (can be normal, massive, inversely graded, chaotic or bimodal). 2) Erosional: basal uncomformity, mud balls, rip-up clasts, reworked fossils produced by scouring. 3) Lithology: Stacks of couplets reflecting marine incursions (often sands) into fresh water or subaerial environments (mud, soil, peat). 4) Fossil: Couplets reflects marine fossils, fresh water fossils or a mixed assemblage. 5) Geomorphology: The sand sheets taper landward and can rise in elevation. 6) Deformation: syn-depositional (soft sediments) and intraformational (stiff sediments).

  6. Extended X-ray absorption fine structure (EXAFS) investigations of Ti bonding environment in sputter-deposited nanocomposite TiBC/a-C thin films

    Energy Technology Data Exchange (ETDEWEB)

    Endrino, J L; Gago, R; Jimenez, I [Instituto de Ciencias de Materiales de Madrid, Consejo Superior de Investigaciones Cientificas, Campus de Cantoblanco, E-28049 Madrid (Spain); Abad, M D; Sanchez-Lopez, J C [Instituto de Ciencia de Materiales de Sevilla, CSIC-Universidad de Sevilla, Avda. Americo Vespucio 49, 41092 Sevilla (Spain); Horwat, D, E-mail: jlendrino@icmm.csic.es [Institut Jean Lamour, Departement CP2S, Nancy Universite, Ecole des Mines, CS14234 Parc de Saurupt, 54042 Nancy Cedex (France)

    2010-06-15

    In this study, we have successfully used the extended X-ray absorption fine structure (EXAFS) technique at the Ti-K edge to extract the local structure in a set of nanocomposite TiBC/a-C coatings deposited by a combined d.c.-pulsed and r.f.-magnetron sputtering deposition process. The sequence of Fourier transform spectra in the deposited films shows that there is an increase in the number of Ti-C bonds in the films of higher carbon content in parallel with the increment of the total carbon content. In addition, Ti-K EXAFS spectra indicate that in all the deposited TiBC/a-C films, first-shell neighbours are in a nearer structural arrangement than the one expected for a bulk hexagonal TiB2, which could be due to the formation of mixed Ti-B-C compound in a structural unit similar to the one found in h-TiB{sub 2}.

  7. METALS DEPOSITS

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    <正>20070291 Gong Ping (Northern Fujian Geological Party, Shaozou 354000) Discussion on Geological Characteristics and Control Factors of the Shimen Au-polymetallic Deposit in Zhenghe County, Fujian Province (Geology of Fujian, ISSN1001-3970, CN38-1080/P, 25(1), 2006, p.18-24, 2 illus., 2 tables, 1 ref.) Key words: gold deposits, polymetallic deposits, Fujian Province

  8. The investigation of atmospheric deposition distribution of organochlorine pesticides (OCPs) in Turkey

    Science.gov (United States)

    Cindoruk, S. Sıddık; Tasdemir, Yücel

    2014-04-01

    Atmospheric deposition is a significant pollution source leading to contamination of remote and clean sites, surface waters and soils. Since persistent organic pollutants (POPs) stay in atmosphere without any degradation, they can be transported and deposited to clean surfaces. Organochlorine pesticides are an important group of POPs which have toxic and harmful effects to living organisms and environment. Therefore, atmospheric deposition levels and characteristics are of importance to determine the pollution quantity of water and soil surfaces in terms of POPs. This study reports the distribution quantities of atmospheric deposition including bulk, dry, wet and air-water exchange of particle and gas phase OCPs as a result of 1-year sampling campaign. Atmospheric deposition distribution showed that the main mechanism for OCPs deposition is wet processes with percentage of 69 of total deposition. OCP compounds' deposition varied according to atmospheric concentration and deposition mechanism. HCH compounds were dominant pesticide species for all deposition mechanisms. HCH deposition constituted the 65% of Σ10OCPs.

  9. Short- and medium-chain chlorinated paraffins in air and soil of subtropical terrestrial environment in the pearl river delta, South China: distribution, composition, atmospheric deposition fluxes, and environmental fate.

    Science.gov (United States)

    Wang, Yan; Li, Jun; Cheng, Zhineng; Li, Qilu; Pan, Xiaohui; Zhang, Ruijie; Liu, Di; Luo, Chunling; Liu, Xiang; Katsoyiannis, Athanasios; Zhang, Gan

    2013-03-19

    Research on the environmental fate of short- and medium-chain chlorinated paraffins (SCCPs and MCCPs) in highly industrialized subtropical areas is still scarce. Air, soil, and atmospheric deposition process in the Pearl River Delta of South China were investigated, and the average SCCP and MCCP concentrations were 5.2 μg/sampler (17.69 ng/m(3)) and 4.1 μg/sampler for passive air samples, 18.3 and 59.3 ng/g for soil samples, and 5.0 and 5.3 μg/(m(2)d) for deposition samples, respectively. Influenced by primary sources and the properties of chlorinated paraffins (CPs), a gradient trend of concentrations and a fractionation of composition from more to less industrialized areas were discovered. Intense seasonal variations with high levels in summer air and winter deposition samples indicated that the air and deposition CP levels were controlled mainly by the vapor and particle phase, respectively. Complex environmental processes like volatilization and fractionation resulted in different CP profiles in different environment matrixes and sampling locations, with C(10-11) C(l6-7) and C(14) C(l6-7), C(10-12) C(l6-7) and C(14) C(l6-8), and C(11-12) C(l6-8) and C(14) C(l7-8) dominating in air, soil, and atmospheric deposition, respectively. Shorter-chain and less chlorinated congeners were enriched in air in the less industrialized areas, while longer-chain and higher chlorinated congeners were concentrated in soil in the more industrialized areas. This is suggesting that the gaseous transport of CPs is the dominant mechanism responsible for the higher concentrations of lighter and likely more mobile CPs in the rural areas.

  10. varying elastic parameters distributions

    KAUST Repository

    Moussawi, Ali

    2014-12-01

    The experimental identication of mechanical properties is crucial in mechanics for understanding material behavior and for the development of numerical models. Classical identi cation procedures employ standard shaped specimens, assume that the mechanical elds in the object are homogeneous, and recover global properties. Thus, multiple tests are required for full characterization of a heterogeneous object, leading to a time consuming and costly process. The development of non-contact, full- eld measurement techniques from which complex kinematic elds can be recorded has opened the door to a new way of thinking. From the identi cation point of view, suitable methods can be used to process these complex kinematic elds in order to recover multiple spatially varying parameters through one test or a few tests. The requirement is the development of identi cation techniques that can process these complex experimental data. This thesis introduces a novel identi cation technique called the constitutive compatibility method. The key idea is to de ne stresses as compatible with the observed kinematic eld through the chosen class of constitutive equation, making possible the uncoupling of the identi cation of stress from the identi cation of the material parameters. This uncoupling leads to parametrized solutions in cases where 5 the solution is non-unique (due to unknown traction boundary conditions) as demonstrated on 2D numerical examples. First the theory is outlined and the method is demonstrated in 2D applications. Second, the method is implemented within a domain decomposition framework in order to reduce the cost for processing very large problems. Finally, it is extended to 3D numerical examples. Promising results are shown for 2D and 3D problems.

  11. Deposition, Accumulation, and Alteration of Cl(-), NO3(-), ClO4(-) and ClO3(-) Salts in a Hyper-Arid Polar Environment: Mass Balance and Isotopic Constraints

    Science.gov (United States)

    Jackson, Andrew; Davila, Alfonso F.; Boehlke, J. K.; Sturchio, Neil C.; Sevanthi, Ritesh; Estrada, Nubia; Brundrette, Megan; Lacell, Denis; McKay, Christopher P.; Poghosyan, Armen; text-decoration: none; " href="javascript:void(0); " onClick="displayelement('author_20160009066'); toggleEditAbsImage('author_20160009066_show'); toggleEditAbsImage('author_20160009066_hide'); "> hide

    2016-01-01

    The salt fraction in permafrost soils/sediments of the McMurdo Dry Valleys (MDV) of Antarctica can be used as a proxy for cold desert geochemical processes and paleoclimate reconstruction. Previous analyses of the salt fraction in MDV permafrost soils have largely been conducted in coastal regions where permafrost soils are variably affected by aqueous processes and mixed inputs from marine and stratospheric sources. We expand upon this work by evaluating permafrost soil/sediments in University Valley, located in the ultraxerous zone where both liquid water transport and marine influences are minimal. We determined the abundances of Cl(-), NO3(-, ClO4(-)and ClO3(-)in dry and ice-cemented soil/sediments, snow and glacier ice, and also characterized Cl(-) and NO3(-) isotopically. The data are not consistent with salt deposition in a sublimation till, nor with nuclear weapon testing fall-out, and instead point to a dominantly stratospheric source and to varying degrees of post depositional transformation depending on the substrate, from minimal alteration in bare soils to significant alteration (photodegradation and/or volatilization) in snow and glacier ice. Ionic abundances in the dry permafrost layer indicate limited vertical transport under the current climate conditions, likely due to percolation of snowmelt. Subtle changes in ClO4(-)/NO3(-) ratios and NO3(-) isotopic composition with depth and location may reflect both transport related fractionation and depositional history. Low molar ratios of ClO3(-)/ClO4(-) in surface soils compared to deposition and other arid systems suggest significant post depositional loss of ClO3(-), possibly due to reduction by iron minerals, which may have important implications for oxy-chlorine species on Mars. Salt accumulation varies with distance along the valley and apparent accumulation times based on multiple methods range from approximately 10 to 30 kyr near the glacier to 70-200 kyr near the valley mouth. The relatively

  12. Deposition, accumulation, and alteration of Cl−, NO3−, ClO4− and ClO3− salts in a hyper-arid polar environment: Mass balance and isotopic constraints

    Science.gov (United States)

    Jackson, Andrew; Davila, Alfonso F.; Böhlke, John Karl; Sturchio, Neil C.; Sevanthi, Ritesh; Estrada, Nubia; Brundrett, Maeghan; Lacelle, Denis; McKay, Christopher P.; Poghosyan, Armen; Pollard, Wayne; Zacny, Kris

    2016-01-01

    The salt fraction in permafrost soils/sediments of the McMurdo Dry Valleys (MDV) of Antarctica can be used as a proxy for cold desert geochemical processes and paleoclimate reconstruction. Previous analyses of the salt fraction in MDV permafrost soils have largely been conducted in coastal regions where permafrost soils are variably affected by aqueous processes and mixed inputs from marine and stratospheric sources. We expand upon this work by evaluating permafrost soil/sediments in University Valley, located in the ultraxerous zone where both liquid water transport and marine influences are minimal. We determined the abundances of Cl−, NO3−, ClO4− and ClO3− in dry and ice-cemented soil/sediments, snow and glacier ice, and also characterized Cl− and NO3−isotopically. The data are not consistent with salt deposition in a sublimation till, nor with nuclear weapon testing fall-out, and instead point to a dominantly stratospheric source and to varying degrees of post depositional transformation depending on the substrate, from minimal alteration in bare soils to significant alteration (photodegradation and/or volatilization) in snow and glacier ice. Ionic abundances in the dry permafrost layer indicate limited vertical transport under the current climate conditions, likely due to percolation of snowmelt. Subtle changes in ClO4−/NO3− ratios and NO3− isotopic composition with depth and location may reflect both transport related fractionation and depositional history. Low molar ratios of ClO3−/ClO4− in surface soils compared to deposition and other arid systems suggest significant post depositional loss of ClO3−, possibly due to reduction by iron minerals, which may have important implications for oxy-chlorine species on Mars. Salt accumulation varies with distance along the valley and apparent accumulation times based on multiple methods range from ∼10 to 30 kyr near the glacier to 70–200 kyr near the valley mouth. The relatively young age

  13. Deposition, accumulation, and alteration of Cl-, NO3-, ClO4- and ClO3- salts in a hyper-arid polar environment: Mass balance and isotopic constraints

    Science.gov (United States)

    Jackson, Andrew; Davila, Alfonso F.; Böhlke, John Karl; Sturchio, Neil C.; Sevanthi, Ritesh; Estrada, Nubia; Brundrett, Maeghan; Lacelle, Denis; McKay, Christopher P.; Poghosyan, Armen; Pollard, Wayne; Zacny, Kris

    2016-06-01

    The salt fraction in permafrost soils/sediments of the McMurdo Dry Valleys (MDV) of Antarctica can be used as a proxy for cold desert geochemical processes and paleoclimate reconstruction. Previous analyses of the salt fraction in MDV permafrost soils have largely been conducted in coastal regions where permafrost soils are variably affected by aqueous processes and mixed inputs from marine and stratospheric sources. We expand upon this work by evaluating permafrost soil/sediments in University Valley, located in the ultraxerous zone where both liquid water transport and marine influences are minimal. We determined the abundances of Cl-, NO3-, ClO4- and ClO3- in dry and ice-cemented soil/sediments, snow and glacier ice, and also characterized Cl- and NO3- isotopically. The data are not consistent with salt deposition in a sublimation till, nor with nuclear weapon testing fall-out, and instead point to a dominantly stratospheric source and to varying degrees of post depositional transformation depending on the substrate, from minimal alteration in bare soils to significant alteration (photodegradation and/or volatilization) in snow and glacier ice. Ionic abundances in the dry permafrost layer indicate limited vertical transport under the current climate conditions, likely due to percolation of snowmelt. Subtle changes in ClO4-/NO3- ratios and NO3- isotopic composition with depth and location may reflect both transport related fractionation and depositional history. Low molar ratios of ClO3-/ClO4- in surface soils compared to deposition and other arid systems suggest significant post depositional loss of ClO3-, possibly due to reduction by iron minerals, which may have important implications for oxy-chlorine species on Mars. Salt accumulation varies with distance along the valley and apparent accumulation times based on multiple methods range from ∼10 to 30 kyr near the glacier to 70-200 kyr near the valley mouth. The relatively young age of the salts and

  14. Advances in understanding of high-Z material erosion and re-deposition in low-Z wall environment in DIII-D

    Science.gov (United States)

    Ding, R.; Rudakov, D. L.; Stangeby, P. C.; Wampler, W. R.; Abrams, T.; Brezinsek, S.; Briesemeister, A.; Bykov, I.; Chan, V. S.; Chrobak, C. P.; Elder, J. D.; Guo, H. Y.; Guterl, J.; Kirschner, A.; Lasnier, C. J.; Leonard, A. W.; Makowski, M. A.; McLean, A. G.; Snyder, P. B.; Thomas, D. M.; Tskhakaya, D.; Unterberg, E. A.; Wang, H. Q.; Watkins, J. G.

    2017-05-01

    Dedicated DIII-D experiments coupled with modeling reveal that the net erosion rate of high-Z materials, i.e. Mo and W, is strongly affected by carbon concentration in the plasma and the magnetic pre-sheath properties. Different methods such as electrical biasing and local gas injection have been investigated to control high-Z material erosion. The net erosion rate of high-Z materials is significantly reduced due to the high local re-deposition ratio. The ERO modeling shows that the local re-deposition ratio is mainly controlled by the electric field and plasma density within the magnetic pre-sheath. The net erosion can be significantly suppressed by reducing the sheath potential drop. A high carbon impurity concentration in the background plasma is also found to reduce the net erosion rate of high-Z materials. Both DIII-D experiments and modeling show that local 13CH4 injection can create a carbon coating on the metal surface. The profile of 13C deposition provides quantitative information on radial transport due to E  ×  B drift and the cross-field diffusion. The deuterium gas injection upstream of the W sample can reduce W net erosion rate by plasma perturbation. In H-mode plasmas, the measured inter-ELM W erosion rates at different radial locations are well reproduced by ERO modeling taking into account charge-state-resolved carbon ion flux in the background plasma calculated using the OEDGE code.

  15. Database of recent tsunami deposits

    Science.gov (United States)

    Peters, Robert; Jaffe, Bruce E.

    2010-01-01

    This report describes a database of sedimentary characteristics of tsunami deposits derived from published accounts of tsunami deposit investigations conducted shortly after the occurrence of a tsunami. The database contains 228 entries, each entry containing data from up to 71 categories. It includes data from 51 publications covering 15 tsunamis distributed between 16 countries. The database encompasses a wide range of depositional settings including tropical islands, beaches, coastal plains, river banks, agricultural fields, and urban environments. It includes data from both local tsunamis and teletsunamis. The data are valuable for interpreting prehistorical, historical, and modern tsunami deposits, and for the development of criteria to identify tsunami deposits in the geologic record.

  16. Depositional environment and organic matter accumulation of Upper Ordovician–Lower Silurian marine shale in the Upper Yangtze Platform, South China

    Science.gov (United States)

    Li, Yangfang; Zhang, Tongwei; Ellis, Geoffrey S.; Shao, Deyong

    2017-01-01

    The main controlling factors of organic matter accumulation in the Upper Ordovician Wufeng–Lower Silurian Longmaxi Formations are complex and remain highly controversial. This study investigates the vertical variation of total organic carbon (TOC) content as well as major and trace element concentrations of four Ordovician–Silurian transition sections from the Upper Yangtze Platform of South China to reconstruct the paleoenvironment of these deposits and to improve our understanding of those factors that have influenced organic matter accumulation in these deposits.The residual TOC content of the Wufeng Formation averages 3.2% and ranges from 0.12 to 6.0%. The overlying lower Longmaxi Formation displays higher TOC content (avg. 4.4%), followed upsection by consistent and lower values that average 1.6% in the upper Longmaxi Formation. The concentration and covariation of redox-sensitive trace elements (Mo, U and V) suggest that organic-rich intervals of the Wufeng Formation accumulated under predominantly anoxic conditions. Organic-rich horizons of the lower Longmaxi Formation were deposited under strongly anoxic to euxinic conditions, whereas organic-poor intervals of the upper Longmaxi Formation accumulated under suboxic conditions. Positive correlations between redox proxies and TOC contents suggest that organic matter accumulation was predominantly controlled by preservation. Barium excess (Baxs) values indicate high paleoproductivity throughout the entire depositional sequence, with an increase in the lower Longmaxi Formation. Increased productivity may have been induced by enhanced P recycling, as evidenced by elevated Corg/Ptot ratios. Mo–U covariation and Mo/TOC values reveal that the Wufeng Formation was deposited under extremely restricted conditions, whereas the Longmaxi Formation accumulated under moderately restricted conditions. During the Late Ordovician, the extremely restricted nature of ocean circulation on the Upper Yangtze Platform in

  17. Indicative function of aromatic hydrocarbon in crude oil on depositional environment%原油芳烃的沉积环境指示作用

    Institute of Scientific and Technical Information of China (English)

    孟江辉; 刘洛夫; 张敏; 王英

    2011-01-01

    In order to study the indicative function of aromatic hydrocarbon in crude oil on the depositional environment,31 crude oil samples from Tazhong marine crude oil,Qaidam salt-lake facies crude oil,Jizhong Sag freshwater-lake facies crude oil and Turpan coal-derived oil basins were chosen for analysis by GC-MS.The results show that the abundances of cadalene and retene in aromatic diterpenoids indicateed the input degree of higher plants for the marine and salt-lake facies crude oils,a lower than 0.24% mass fraction of cadalene in naphthaline series and a lower than 1.21% mass fraction of retene in phenanthrene series.However,these two values are in the range of 0.12%-8.65% and 0.71%-20.03% in the freshwater-lake facies and coal-derived oils,respectively.Dibenzothiophene and dibenzofuran may be derived from the same precursor compound,but fluorenes have different genesis,and the value of dibenzothiophene/dibenzofuran ratio can reflect redox condition,whch is generally higher than 0.7 in the marine and salt-lake facies crude oils,0.48 in the freshwater-lake facies crude oil and lower than 0.14 in the coal-derived oil.The ratio of dibenzothiophene/phenanthrene is the most effective parameter to distinguish between marine(0.25) and terrestrial(0.2) crude oils.The salt-lake facies crude oil is characterized by high abundance of triaromatic steroid(triaromatic steroid series/aromatic hydrocarbon ratio 12%) and C26/C28(20S) triaromatic steroid ratio(0.45).The coal-derived oil contains whole benzohopane series typically.%为了研究原油芳烃在沉积环境方面的指示作用,采用色谱-质谱仪对塔中地区海相原油、柴达木盆地咸水湖相原油、冀中坳陷淡水湖相原油以及吐哈盆地煤成油等31个原油样品进行了全油GC-MS分析.研究结果表明:芳构化二萜类的卡达烯和惹烯的丰度指示着高等植物输入强度,海相和咸水湖相原油卡达烯在萘系列中的质量分数小于0.24%,惹烯

  18. Isotropic metal deposition technique for metamaterials fabrication

    DEFF Research Database (Denmark)

    Malureanu, Radu; Andryieuski, Andrei; Lavrinenko, Andrei

    2009-01-01

    In this work we will present the first steps taken towards isotropic deposition of thin metallic layers on dielectric substrates. The deposition takes place in aqueous environment thus making it both cheap and easy to be implemented....

  19. Isotropic metal deposition technique for metamaterials fabrication

    DEFF Research Database (Denmark)

    Malureanu, Radu; Andryieuski, Andrei; Lavrinenko, Andrei

    2009-01-01

    In this work we will present the first steps taken towards isotropic deposition of thin metallic layers on dielectric substrates. The deposition takes place in aqueous environment thus making it both cheap and easy to be implemented....

  20. Depositional environments and cyclo- and chronostratigraphy of uppermost Carboniferous-Lower Triassic -lacustrine deposits, southern Bogda Mountains, NW China - A terrestrfluvialial paleoclimatic record of mid-latitude NE Pangea

    Science.gov (United States)

    Yang, W.; Feng, Q.; Liu, Yajing; Tabor, N.; Miggins, D.; Crowley, J.L.; Lin, J.; Thomas, S.

    2010-01-01

    Two uppermost Carboniferous-Lower Triassic fluvial-lacustrine sections in the Tarlong-Taodonggou half-graben, southern Bogda Mountains, NW China, comprise a 1834. m-thick, relatively complete sedimentary and paleoclimatic record of the east coast of mid-latitude NE Pangea. Depositional environmental interpretations identified three orders (high, intermediate, and low) of sedimentary cycles. High-order cycles (HCs) have five basic types, including fluvial cycles recording repetitive changes of erosion and deposition and lacustrine cycles recording repetitive environmental changes associated with lake expansion and contraction. HCs are grouped into intermediate-order cycles (ICs) on the basis of systematic changes of thickness, type, and component lithofacies of HCs. Nine low-order cycles (LCs) are demarcated by graben-wide surfaces across which significant long-term environmental changes occurred. A preliminary cyclostratigraphic framework provides a foundation for future studies of terrestrial climate, tectonics, and paleontology in mid-latitude NE Pangea.Climate variabilities at the intra-HC, HC, IC, and LC scales were interpreted from sedimentary and paleosol evidence. Four prominent climatic shifts are present: 1) from the humid-subhumid to highly-variable subhumid-semiarid conditions at the beginning of Sakamarian; 2) from highly-variable subhumid-semiarid to humid-subhumid conditions across the Artinskian-Capitanian unconformity; 3) from humid-subhumid to highly-variable subhumid-semiarid conditions at early Induan; and 4) from the highly-variable subhumid-semiarid to humid-subhumid conditions across the Olenekian-Anisian unconformity. The stable humid-subhumid condition from Lopingian to early Induan implies that paleoclimate change may not have been the cause of the end-Permian terrestrial mass extinction. A close documentation of the pace and timing of the extinction and exploration of other causes are needed. In addition, the semiarid-subhumid conditions

  1. Adaptive social learning strategies in temporally and spatially varying environments : how temporal vs. spatial variation, number of cultural traits, and costs of learning influence the evolution of conformist-biased transmission, payoff-biased transmission, and individual learning.

    Science.gov (United States)

    Nakahashi, Wataru; Wakano, Joe Yuichiro; Henrich, Joseph

    2012-12-01

    Long before the origins of agriculture human ancestors had expanded across the globe into an immense variety of environments, from Australian deserts to Siberian tundra. Survival in these environments did not principally depend on genetic adaptations, but instead on evolved learning strategies that permitted the assembly of locally adaptive behavioral repertoires. To develop hypotheses about these learning strategies, we have modeled the evolution of learning strategies to assess what conditions and constraints favor which kinds of strategies. To build on prior work, we focus on clarifying how spatial variability, temporal variability, and the number of cultural traits influence the evolution of four types of strategies: (1) individual learning, (2) unbiased social learning, (3) payoff-biased social learning, and (4) conformist transmission. Using a combination of analytic and simulation methods, we show that spatial-but not temporal-variation strongly favors the emergence of conformist transmission. This effect intensifies when migration rates are relatively high and individual learning is costly. We also show that increasing the number of cultural traits above two favors the evolution of conformist transmission, which suggests that the assumption of only two traits in many models has been conservative. We close by discussing how (1) spatial variability represents only one way of introducing the low-level, nonadaptive phenotypic trait variation that so favors conformist transmission, the other obvious way being learning errors, and (2) our findings apply to the evolution of conformist transmission in social interactions. Throughout we emphasize how our models generate empirical predictions suitable for laboratory testing.

  2. Neoproterozoic Molar-tooth Structure and Constraint of Depositional Facies and Environment in the North China Platform in Jiangsu, Anhui and Liaoning, Eastern China

    Institute of Scientific and Technical Information of China (English)

    LIU Yongqing; GAO Linzhi; LIU Yanxue

    2005-01-01

    Molar tooth structure (MTS) represented by complex ptygmatical shapes is widely distributed in the Proterozoic of the world.MTS filled by fine,equant sparry calcite (or dolomite) displays an abrupt contact with hosting rocks,which are mainly composed of carbonaceous micrites and fine-grained carbonates with local silts and stormdominated deposits with graded,cross or wave beddings,numerous erosional surfaces and truncated and fills or guttered bases.Occurrence of MTS suggests a result of the constraint of sedimentary facies,and the storm-base in ramp settings is the maximum depth for the formation of MTS.Vertical succession of MTS-bearing carbonates shows a deposition stacked by high-frequency shallow subtidal and peritidal cycles.An individual cyclic MTS-bearing sequence is characterized by thinning,shallowing and dynamic decreasing-upward,and peritidal caps of purple red iron and organic carbonaceous sediments with more complicated shapes of MTS are common on the top of individual MTS-bearing sequences.

  3. Ion beam sputter deposition of low-defect EUV mask blanks on 6-in. LTEM substrates in a real production environment

    Science.gov (United States)

    Becker, Hans W.; Aschke, Lutz; Schubert, Birgit; Krieger, Juergen; Lenzen, Frank; Yulin, Sergey A.; Feigl, Torsten; Kuhlmann, Thomas; Kaiser, Norbert

    2002-07-01

    EUV mask blanks consist of two thin film systems deposited on low thermal expansion 6 inch substrates (LTEM). First there is the multilayer stack with around 100 alternating layers of elements with different optical properties which are topped by a capping layer. Beside optimal optical properties it is also necessary to improve the heat stability of the layer system. The absorber stack which consists of a buffer and an absorber layer is next. Here a minimum absorption of EUV light of 99 percent is required. The stress in both layer systems should be as low as possible. The reduction of defects to an absolute minimum is one of the main challenges. The high-reflective Mo/Si multilayer coatings were designed for normal incidence reflectivity and successfully deposited on 6-inch LTEM substrates by ion-beam sputtering. X-ray scattering, transmission electron microscopy and atomic force microscopy were used for characterization of the multilayer interfaces and the surface morphology. The results are correlated to the measured normal incidence reflectivity using synchrotron radiation at the PTB reflectometer at BESSY II, Berlin, Germany.

  4. The origin of bimodal grain-size distribution for aeolian deposits

    Science.gov (United States)

    Lin, Yongchong; Mu, Guijin; Xu, Lishuai; Zhao, Xue

    2016-03-01

    Atmospheric dust deposition is a common phenomenon in arid and semi-arid regions. Bimodal grain size distribution (BGSD) (including the fine component and coarse component) of aeolian deposits has been widely reported. But the origin of this pattern is still debated. Here, we focused on the sedimentary process of modern dust deposition, and analyzed the grain size distribution of modern dust deposition, foliar dust, and aggregation of the aeolian dust collected in Cele Oasis, southern margin of Tarim Basin. The results show that BGSD also appear in a dust deposition. The content of fine components (dust storm is significant less than that from subsequent floating dust. Fine component also varies with altitude. These indicate that modern dust deposition have experienced changing aerodynamic environment and be reworked during transportation and deposition, which is likely the main cause for BGSD. The dusts from different sources once being well-mixed in airflow are hard to form multiple peaks respectively corresponding with different sources. In addition, the dust deposition would appear BGSD whether aggregation or not. Modern dust deposition is the continuation of ancient dust deposition. They both may have the same cause of formation. Therefore, the origin of BGSD should provide a theoretical thinking for reconstructing the palaeo-environmental changes with the indicator of grain size.

  5. Usage of microbial mats in depostional environment interpretation and sea level changes: A study of carbonate deposits of members 1 to 2 of the Mila Group (Deh-Sufiyan Formation in Central Alborz

    Directory of Open Access Journals (Sweden)

    Aram Bayetgol

    2015-05-01

    Full Text Available Carbonate deposits of members 1 to 2 of the Mila Group (Middle Cambrian in Central Alborz that call Deh-Sufiyan Formation in this research, were studied in Shahmirzad, Tueh-Darvar, Mila-Kuh and Deh-Molla sections. These sediments were deposited in four facies belts on a carbonate ramp including basinal environments, outer ramp (deep subtidal sequences, mid ramp (shallow subtidal to lower intertidal sequences, and inner ramp (shoal and upper intertidal to supratidal sequences. Various microbialites were recognized in the shallow-water sediments (includes subtidal and intertidal of this unit. Based on this study, microbial mats have various morphology of form and type of growth structure and inluding laminar to wavy-laminar, domal or hemispheroidal, bulbous, columnar, regular flabellate columns, unlaminated, loaf- to mound-shaped thrombolities. Facies associations of Deh-Sufiyan Formation are arranged in small-scale of peritidal, shallow subtidal, and deep subtidal cycles and microbial mats are the major features of them. The trends of vertical changes of facies in shallowing-upward and deepening-upward cycles and distribution of various types of microbialites in these cycles had been related to depostional environments and their postions on carbonate ramp. Basal classification method used in this study can provide valuable informations for application of microbiali mats in paleo-environmental and sequence stratigraphy analysis.

  6. Nitrogen Deposition Effects on Soil Carbon Dynamics in Temperate Forests

    DEFF Research Database (Denmark)

    Ginzburg Ozeri, Shimon

    Soils contain the largest fraction of terrestrial carbon (C). Understanding the factors regulating the decomposition and storage of soil organic matter (SOM) is essential for predictions of the C sink strength of the terrestrial environment in the light of global change. Elevated long-term nitrogen...... (N) deposition into forest ecosystems has been increasing globally and was hypothesized to raise soil organic C (SOC) stocks by increasing forest productivity and by reducing SOM decomposition. Yet, these effects of N deposition on forest SOC stocks are uncertain and largely based on observations...... edges were used to study the effects of varying N deposition load on SOC stocks and fluxes as well as on the temperature sensitivity of SOM respiration. In a third study, the effects of 20 years of continuous experimental N addition (35 kg N ha-1 year-1) on soil C budget were investigated. Our general...

  7. Performance of HIPIMS deposited CrN/NbN nanostructured coatings exposed to 650 °C in pure steam environment

    Energy Technology Data Exchange (ETDEWEB)

    Hovsepian, P. Eh., E-mail: P.Hovsepian@shu.ac.uk [UK National HIPIMS Technology Centre, Materials and Engineering Research Institute, Howard Street, Sheffield Hallam University, Sheffield, S1 1WB (United Kingdom); Ehiasarian, A.P.; Purandare, Y.P.; Biswas, B. [UK National HIPIMS Technology Centre, Materials and Engineering Research Institute, Howard Street, Sheffield Hallam University, Sheffield, S1 1WB (United Kingdom); Pérez, F.J.; Lasanta, M.I.; Miguel, M.T. de; Illana, A. [Grupo de Ingeniería de Superficies y Materiales Nanoestructurados, Facultad de Ciencias Químicas, Universidad Complutense de Madrid, 28040, Madrid (Spain); Juez-Lorenzo, M. [Fraunhofer Institut für Chemische Technologie ICT, Joseph-von-Fraunhofer-Straße 7, 76327, Pfinztal (Germany); Muelas, R. [Ingeniería de Sistemas para la Defensa de España SA, Beatriz de Bobadilla No. 3, Madrid, 28040 (Spain); Agüero, A. [Instituto Nacional de Técnica Aeroespacial (INTA), Ctra. Ajalvir Km. 4, 28850, Torrejón de Ardoz, Madrid (Spain)

    2016-08-15

    In the current work, 4 μm thick CrN/NbN coating utilising nanoscale multilayer structure with bi-layer thickness of Δ = 2.9 nm has been used to protect 9 wt% Cr steels such as P92 widely used in steam power plants. The uniquely layered coatings have a combination of nitrides of chromium and niobium which are not only resistant to aqueous corrosion and corrosion-erosion and have excellent tribological properties, but also have oxidation resistance in dry air up to a temperature of 850 °C. The novel High Power Impulse Magnetron Sputtering (HIPIMS) deposition technology has been used to deposit CrN/NbN with enhanced adhesion (critical load of scratch adhesion L{sub C2} = 80 N) and a very dense microstructure as demonstrated by Transmission Electron Microscopy (TEM) imaging. These superior coating properties are achieved due to the unique high metal ion content (up to 90%) in the HIPIMS plasma, which allows particle acceleration and trajectory control by external electrical and magnetic fields thus delivering highly energetic material flux on the condensing surface. P92 bare and coated samples were oxidised at 650 °C in 100% steam atmosphere up to 2000 h, in order to simulate the future operation conditions of steam turbines employed in power plants. The oxidation kinetics was evaluated by mass gain measurements. Under these conditions CrN/NbN provided reliable protection of the P92 steel. The paper also discusses the effect of growth defects and high temperature crack formation analysed by Scanning Electron Microscopy and Focused Ion Beam-Scanning Electron Microscopy techniques (SEM and FIB-SEM, respectively) on the high temperature corrosion resistance in pure steam atmosphere thus revealing the coatings potential failure mechanisms. - Highlights: • Benefit of highly ionised metal plasma flux for coating deposition demonstrated. • CrN/NbN coating-superior corrosion resistance against high temperature steam shown. • CrN/NbN film-steel substrate

  8. NONMETALS DEPOSITS

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    <正>20102406 Chen Gang(China University of Geosciences,Beijing 100083,China);Li Fengming Discussion on Geological Characteristics and Genesis of Yuquanshan Graphite Deposit of Xinjiang(Xinjiang Geology,ISSN1000-8845,CN65-1092/P,27(4),2009,p.325-329,4 illus.,4 tables,5 refs.)Key words:graphite deposit,XinjiangYuquanshan graphite deposit of Xinjiang occurs in mica-quartz schist of Xingeer Information which belongs to Xinditate Group of Lower Pt in Kuluketage Block of Tarim paleo-continent,and experiences two mineralizing periods of

  9. 慕士塔格冰芯中近百年来细菌数量与气候环境变化的关系%BACTERIAL ABUNDANCE VARY IN MUZTAGATA ICE CORE AND RESPOND TO CLIMATE AND ENVIRONMENT CHANGE IN THE PAST HUNDRED YEARS

    Institute of Scientific and Technical Information of China (English)

    刘勇勤; 姚檀栋; 徐柏青; 焦念志; 骆庭伟; 邬光剑; 赵华标; 沈亮; 刘晓波

    2013-01-01

    The used flow cytometry to analysed the bacterial abundance in top 56. 27m of 73m Muztagata ice core which was drilled from accumulating zone(6300m above sea level; 38°17′N,75°06′E) at Muztagata Glacier located on the western of the Tibetan Plateau. Bacterial abundances of 292 samples obtained from the ice core ranged from 0. 43×103 cells/ml to 13. 32×103 cells/ml, with an average value 2. 64×103 cells/ml. Date of the 56. 27m long ice core was determined according black carbon concentration and spanned from 1907 to 2000. The results presents annual bacterial abundances deposited in Muztagata ice core over the past 93 years. The bacterial abundance varied from 0. 66×103 cells/ml (1982)to 6. 91×103 cells/ml (1912) .with average value 2. 59×103 cells/ml. Ten periods of bacterial abundance, 6 peak periods and 4 low value periods, respond to the high and low temperature stages which indicated by the oxygen isotope ratios, respectively. Bacterial abundance significently correlated to oxygen isotope ratios, Na+, NH+4, K+, Mg +, Ca + , Cl-, and NO-3concentration. Temperature, anthropogenic and dust influence the bacterial abundance in the Muztagata ice core. The bacterial abundance in the Muztagata ice core are lower than that in Geladangdong ice core located on the central of the Tibetan Plateau, and are less influence by dust. It is possibely due to the Muztagata ice core located in the barren desert region, while the Geladangodng ice core located in the alpine steppe region. The different bacterial abundance between the two ice cores imply that the bacteria in ice core are sensitively respond to the ecosystem environment where they surround.%应用流式细胞技术分析了取自青藏高原西部慕士塔格冰川73m冰芯上部56.27m中细菌的数量变化,在1907~2000年的93年中,细菌年平均数在0.66×103ml(1982年)至6.91×103个/ml(1912年)之间变化,平均2.59×103个/ml.细菌数量的变化可分为10个不同的阶段,其中6

  10. A revised Mississippian lithostratigraphy of County Galway (western Ireland) with an analysis of carbonate lithofacies, biostratigraphy, depositional environments and palaeogeographic reconstructions utilising new borehole data

    Institute of Scientific and Technical Information of China (English)

    Markus Pracht; Ian D Somerville

    2015-01-01

    AbstractAn integrated study of borehole data and outcrop of Mississippian (late Tour-naisian to late Viséan) rocks in Co. (County) Galway, western Ireland has enabled a more detailed geological map and lithostratigraphy to be constructed for the region. Several car-bonate formations have been distinguished by microfacies analysis and their precise ages established by micropalaeontological investigations using foraminifers and calcareous algae. In addition, palaeogeographic maps have been constructed for the late Tournaisian, and ear-ly to late Viséan intervals in the region. The oldest marine Mississippian (late Tournaisian) deposits are recorded in the south of the study region from the Loughrea/Tynagh area and further south in the Gort Borehole; they belong to the Limerick Province. They comprise the Lower Limestone Shale Group succeeded by the Ballysteen Group, Waulsortian Limestone and Kilbryan Limestone Formations. These rocks were deposited in increasing water depth associated with a transgression that moved northwards across Co. Galway. In the northwest and north of the region, marginal marine and non-marine Tournaisian rocks are developed, with a shoreline located NW of Galway City (Galway High). The central region of Co. Galway has a standard Viséan marine succession that can be directly correlated with the Carrick-on-Shannon succession in counties Leitrim and Roscommon to the northeast and east as far as the River Shannon. It is dominated by shallow-water limestones (Oakport, Ballymore and Croghan Limestone Formations) that formed the Galway-Roscommon Shelf. This facies is lat-erally equivalent to the Tubber Formation to the south which developed on the Clare-Galway Shelf. In the southeast, basinal facies of the Lucan Formation accumulated in the Athenry Ba-sin throughout much of the Viséan. This basin formed during a phase of extensional tectonics in the early Viséan and was probably connected to the Tynagh Basin to the east. In the late Vis

  11. NONMETALS DEPOSITS

    Institute of Scientific and Technical Information of China (English)

    2014-01-01

    <正>20140876 Gao Junbo(College of Resources and Environmental Engineering,Guizhou University,Guiyang 550025,China);Yang Ruidong Study on the Strontium Isotopic Composition of Large Devonian Barite Deposits from Zhenning,Guizhou Province(Geochimica,

  12. NONMETALS DEPOSITS

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    <正>20122457 Cai Jianshe ( Fujian Institute of Geological Survey and Drawing,Fuzhou 350011,China ) On the Geologic Characteristics and Genesis of the Longtangsi Fluorite Deposit in Pucheng County,Fujian Province ( Geology of Fujian,ISSN1001-3970,CN35-1080 / P,30 ( 4 ), 2011,p.301-306,3illus.,1table,6 refs.,with English abstract ) Key words:fluorspar deposit,Fujian Province

  13. Single-grain OSL chronologies for Middle Palaeolithic deposits at El Mnasra and El Harhoura 2, Morocco: implications for Late Pleistocene human-environment interactions along the Atlantic coast of northwest Africa.

    Science.gov (United States)

    Jacobs, Zenobia; Roberts, Richard G; Nespoulet, Roland; El Hajraoui, Mohammed Abdeljalil; Debénath, André

    2012-03-01

    Optically stimulated luminescence (OSL) measurements were made on individual, sand-sized grains of quartz from Middle Palaeolithic deposits at two cave sites (El Harhoura 2 and El Mnasra) on the Atlantic coast of Morocco. We were able to calculate OSL ages for 32 of the 33 samples collected from the Middle Palaeolithic deposits, including the earliest and latest Aterian levels at both sites. These ages reveal periods of occupation between about 110 and 95 ka (thousands of years ago), and at ~75 ka. A late Middle Palaeolithic occupation of El Harhoura 2 is also recorded at ~55 ka. Our single-grain OSL chronologies largely support previous age estimates from El Mnasra and other sites along the Atlantic coast of Morocco, but are generally more precise, reproducible and stratigraphically more coherent (i.e., fewer age reversals). We compare the single-grain ages for El Harhoura 2 and El Mnasra with those obtained from single- and multi-grain OSL dating of Middle Palaeolithic deposits in the nearby sites of Contrebandiers and Dar es-Soltan 1 and 2, and with records of past regional environments preserved in sediment cores collected from off the coast of northwest Africa. A conspicuous feature of the new chronologies is the close correspondence between the three identified episodes of human occupation and periods of wetter climate and expanded grassland habitat. Owing to the precision of the single-grain OSL ages, we are able to discern gaps in occupation during Marine Isotope Stages 5 and 4, which may represent drier periods with reduced vegetation cover. We propose that these climatic conditions can be correlated with events in the North Atlantic Ocean that exert a major control on abrupt, millennial-scale fluctuations between wet and dry periods in northwest and central North Africa.

  14. Multidisciplinary distinction of mass-movement and flood-induced deposits in lacustrine environments: implications for Holocene palaeohydrology and natural hazards (Lake Ledro, Southern Alps, Italy

    Directory of Open Access Journals (Sweden)

    A. Simonneau

    2012-08-01

    Full Text Available High-resolution seismic profiles and sediment cores from Lake Ledro combined with soil and river-bed samples from the lake's catchment area are used to assess the recurrence of natural hazards (earthquakes and flood events in the southern Italian Alps during the Holocene. Two well-developed deltas and a flat central basin are identified on seismic profiles in Lake Ledro. Lake sediments are finely laminated in the basin since 9000 cal. yr BP and frequently interrupted by two types of sedimentary events: light-coloured massive layers and dark-coloured graded beds. Optical analysis (quantitative organic petrography of the organic matter occurring in soils, river beds and lacustrine samples together with lake-sediment bulk density and grain-size analysis illustrate that light-coloured layers consist of a mixture of lacustrine sediments and mainly contain algal particles similar to the ones observed in background sediments. Light-coloured layers thicker than 1.5 cm in the main basin of Lake Ledro are dense and synchronous to numerous coeval mass-wasting deposits remoulding the slopes of the basin. They are interpreted as subaquatic mass movements triggered by historical and pre-historical regional earthquakes dated to 2005 AD, 1891 AD, 1045 AD and 1260, 2545, 2595, 3350, 3815, 4740, 7190, 9185 and 11495 cal. yr BP. Dark-coloured sedimentary event are dense and develop high-amplitude reflections in front of the deltas and in the deep central basin. These beds are mainly made of terrestrial organic matter (soils and ligno-cellulosic debris and are interpreted as resulting from intense hyperpycnal flood events. Mapping and quantifying the amount of soil material accumulated in the Holocene hyperpycnal flood deposits of the sequence and applying the De Ploey erosion model allow estimating that the equivalent soil thickness eroded over the catchment area reached up to 4 mm during the largest Holocene flood events. Such significant soil erosion is

  15. Bouncing universes with varying constants

    Energy Technology Data Exchange (ETDEWEB)

    Barrow, John D [DAMTP, Centre for Mathematical Sciences, Cambridge University, Wilberforce Road, Cambridge CB3 0WA (United Kingdom); Kimberly, Dagny [Theoretical Physics, Blackett Laboratory, Imperial College, Prince Consort Road, London SW7 2BZ (United Kingdom); Magueijo, Joao [Theoretical Physics, Blackett Laboratory, Imperial College, Prince Consort Road, London SW7 2BZ (United Kingdom)

    2004-09-21

    We investigate the behaviour of exact closed bouncing Friedmann universes in theories with varying constants. We show that the simplest BSBM varying alpha theory leads to a bouncing universe. The value of alpha increases monotonically, remaining approximately constant during most of each cycle, but increasing significantly around each bounce. When dissipation is introduced we show that in each new cycle the universe expands for longer and to a larger size. We find a similar effect for closed bouncing universes in Brans-Dicke theory, where G also varies monotonically in time from cycle to cycle. Similar behaviour occurs also in varying speed of light theories.

  16. Bouncing Universes with Varying Constants

    CERN Document Server

    Barrow, J D; Magueijo, J; Barrow, John D.; Kimberly, Dagny; Magueijo, Joao

    2004-01-01

    We investigate the behaviour of exact closed bouncing Friedmann universes in theories with varying constants. We show that the simplest BSBM varying-alpha theory leads to a bouncing universe. The value of alpha increases monotonically, remaining approximately constant during most of each cycle, but increasing significantly around each bounce. When dissipation is introduced we show that in each new cycle the universe expands for longer and to a larger size. We find a similar effect for closed bouncing universes in Brans-Dicke theory, where $G$ also varies monotonically in time from cycle to cycle. Similar behaviour occurs also in varying speed of light theories.

  17. Parametric Study of Heat Deposition from Collision Debris into the Insertion Superconducting Magnets for the LHC Luminosity Upgrade

    CERN Document Server

    Hoa, C; Cerutti, F; Koutchouk, Jean-Pierre; Sterbini, G; Wildner, E

    2007-01-01

    With a new geometry in a higher luminosity environment, the power deposition in the superconducting magnets becomes a critical aspect to analyze and to integrate in the insertion design. In this paper, we quantify the power deposited in magnets insertion at variable positions from the interaction point (IP). A fine characterization of the debris due to the proton-proton collisions at 7 TeV, shows that the energetic particles in the very forward direction give rise to non intuitive dependences of the impacting energy on the magnet front face and inner surface. The power deposition does not vary significantly with the distance to the interaction point, because of counterbalancing effects of different contributions to power deposition. We have found out that peak power density in the magnet insertion does not vary significantly with or without the Target Absorber Secondaries (TAS) protection.

  18. NONMETALS DEPOSITS

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    <正>20110947 Chen Xinglong(Guizhou Bureau of Nonferrous Metal and Nuclear Geology,Guiyang 550005,China);Gong Heqiang Endowment Factors and Development & Utilization Strategy of Bauxite Resource in North Guizhou Province(Guizhou Geology,ISSN1000-5943,CN52-1059/P,27(2),2010,p.106-110,6 refs.,with English abstract)Key words:bauxite deposit,Guizhou Province20110948 Dang Yanxia(Mineral Resource & Reservoir Evaluation Center,Urumiq 830000,China);Fan Wenjun Geological Features and a Primary Study of Metallogenesis of the Wucaiwang Zeolite Deposit,Fuyun County(Xinjiang Geology,ISSN1000-8845,CN65-1092/P,28(2),2010,p.167-170,2 illus.,1 table,5 refs.)Key words:zeolite deposit,Xinjiang Nearly all zeolite deposits in the world result from low-temperature-alteration of glass-bearing volcanic rocks.The southern slope of the Kalamali Mountain is one of the regions where medium to acid volcanics are major lithological type,thus it is a preferred area to look for zeolite deposit.The Wucaiwang zeolite ore district consists of mainly acid volcanic-clastic rocks.

  19. Organic geochemistry of endoevaporitic environments: Microbial diversity and lipid biomarkers from gypsum deposits at the E.S.S.A Salt Works, Guerrero Negro, Baja, Mexico

    Science.gov (United States)

    Vogel, M. B.; Des Marais, D. J.; Jahnke, L. L.; Turk, K. A.; Kubo, M. D.

    2006-12-01

    microbial populations and organic matter diagenesis. This locality is relevant to extremophile studies because it is a biological analogue for evaporite deposits recently discovered on Mars and constitutes a complex hypersaline ecosystem where extreme sulfate concentrations affect carbon and oxygen cycles.

  20. Characteristics and source appointment of atmospheric particulate mercury over East China Sea: Implication on the deposition of atmospheric particulate mercury in marine environment.

    Science.gov (United States)

    Duan, Lian; Cheng, Na; Xiu, Guangli; Wang, Fujiang; Chen, Ying

    2017-02-12

    Total Suspended Particulate (TSP) samples were collected at Huaniao Island in northern East China Sea (ECS) from March 2012 to January 2013. Chemical analysis were conducted to measure the concentration of total particulate mercury (TPM) and speciated particulate mercury including HCl-soluble particulate mercury (HPM), elemental particulate mercury (EPM) and residual particulate mercury (RPM). The bromine (Br) and iodine (I) on particles were also detected. The mean concentration of TPM during the study period was 0.23 ± 0.15 ng m(-3), while the obviously seasonal variation was found that the concentrations of TPM in spring, summer, fall and winter were 0.34 ± 0.20 ng m(-3), 0.15 ± 0.03 ng m(-3), 0.15 ± 0.05 ng m(-3) and 0.27 ± 0.26 ng m(-3), respectively. The statistically strong correlation of bromine and iodine to HPM was only found in spring with r = 0.81 and 0.77 (p < 0.01), respectively. While the strongest correlations between EPM and bromine and iodine were found in winter with r = 0.92 (Br) and 0.96 (I) (p < 0.01), respectively. The clustered 72-h backward trajectories of different seasons and the whole sampling period were categorized into 4 groups. In spring, the clusters passed a long distance across the East China Sea and brought about low concentration of mercury due to the deposition of mercury over the sea. The cluster of air mass across the sea had low concentration of HPM in winter, which suggested that the oxidation of mercury in winter might be related to other oxidants. During the whole sampling period, the air mass from the north of China contributed to the higher concentration of TPM in Huaniao Island.

  1. METALS DEPOSITS

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    <正>20091594 Bao Yafan(The Third Geologic Survey of Jilin Province,Siping 136000,China);Liu Yanjun Relations between Bashenerxi Granite,West Dongkunlun and Baiganhu Tungsten-Tin Deposit(Jilin Geology,ISSN1001-2427,CN22-1099/P,27(3),2008,p.56-59,67,5 illus.,2 tables,7 refs.,with English abstract)Key words:tungsten ores,tin ores,monzogranite,Kunlun Mountains20091595 Chen Fuwen(Yichang Institute of Geology and Mineral Resources,China Geological Survey,Yichang 443003,China);Dai Pingyun Metallogenetic and Isotopic Chronological Study on the Shenjiaya Gold Deposit in Xuefeng Mountains,Hunan Province(Acta Geologica Sinica,ISSN0001-5717,CN11-1951/P,82(7),2008,p.906-911,3 illus.,2 tables,30 refs.)Key words:gold ores,HunanThe Shenjiaya gold deposit is a representative one

  2. Short-chain (C{sub 21} and C{sub 22}) diasteranes in petroleum and source rocks as indicators of maturity and depositional environment

    Energy Technology Data Exchange (ETDEWEB)

    Requejo, A.G. [Texas A & M Univ., College Station, TX (United States)]|[Exxon Production Research Co., Houston, TX (United States); McDonald, T.J.; Sassen, R. [Texas A & M Univ., College Station, TX (United States)] [and others

    1997-07-01

    Geochemical analysis of steranes in source rocks from the Western Canada Basin has allowed the identification of several C{sub 21} and C{sub 22} short-chain sterane isomers. The principal compounds in carbonates from the U. Jurassic Nordegg Formation have been identified as diginane and homodiginane, more thermodynamically-stable isomers of the compounds pregnane and homopregnane that have 5{alpha}, 14{beta},17{beta}(H) stereochemistry. The Triassic Doig formation also contains two compounds tentatively identified on the basis of geologic and geochemical data as diapregnane and diahomopregnane, rearranged isomers of pregnane and homopregnane with methyl substitution at the 5- and 14-carbon positions. The distribution of these compounds parallels that of the higher molecular weight diasteranes. A well-defined relationship is evident between the ratio Fe/S and short-chain diasterane content: samples with Fe/S approximately <0.90 exhibit low diasterane contents, while those with Fe/S approximately >0.90 exhibit high diasterane content. This threshold Fe/S value is nearly equal to the value associated with stoichiometric pyrite (0.87) and suggests that the abundance of short-chain diasteranes is related to excess iron associated with detrital clays. This is consistent with the accepted mechanism of sterane rearrangement, which is thought to proceed via catalysis of clay minerals. In contrast to the higher molecular-weight diasteranes, which increase in abundance relative to other sterane isomers with increasing thermal maturation, the abundance of the rearranged short-chain compounds varies little relative to diginane or homodiginane in a maturity suite from the U. Devonian Duvernay Formation. 38 refs., 11 figs., 3 tabs.

  3. METALS DEPOSITS

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    <正>20111705 An Junbo(Team 603,Bureau of Nonferrous Metals Geological Exploration of Jilin Province,Hunchun 133300,China);Xu Renjie Geological Features and Ore Genesis of Baishilazi Scheelite Deposit in Yanbian Area(Jilin Geology,ISSN1001-2427,CN22-1099/P,29(3),2010,p.39-43,2 illus.,2 tables,7 refs.)Key words:tungsten ores,Jilin ProvinceThe Baishilazi scheelite deposit is located in contacting zone between the marble of the Late Palaeozoic Qinglongcun Group and the Hercynian biotite granite.The vein and lenticular major ore body is obviously controlled by NE-extending faults and con

  4. Analysing the Cenozoic depositional record

    DEFF Research Database (Denmark)

    Goledowski, Bartosz; Clausen, O.R.; Nielsen, S.B.

    It is well known that sediment deposition in the North Sea and on the Norwegian Shelf varied significantly during the Cenozoic as a consequence of varying erosion rate mainly in Western Scandinavia, in Scotland and in the Alps. Recent results have demonstrated that a causal relationship exists...... of variations in erosion rates. Here we present the rationale behind the project, the data available and some preliminary results. The dense seismic and well coverage in the area makes it possible to estimate the rate of deposition of matrix mass. Assuming that sediment storage is not important, this provides...

  5. Short-chain (C 21 and C 22) diasteranes in petroleum and source rocks as indicators of maturity and depositional environment

    Science.gov (United States)

    Requejo, A. G.; Hieshima, G. B.; Hsu, C. S.; McDonald, T. J.; Sassen, R.

    1997-07-01

    Geochemical analysis of steranes in source rocks from the Western Canada Basin has allowed the identification of several C 21 and C 22 short-chain sterane isomers. The principal compounds in carbonates from the U. Jurassic Nordegg Formation have been identified as diginane and homodiginane, more thermodynamically-stable isomers of the compounds pregnane and homopregnane that have 5α,14β,17β(H) stereochemistry. The Triassic Doig formation also contains two compounds tentatively identified on the basis of geologic and geochemical data as diapregnane and diahomopregnane, rearranged isomers of pregnane and homopregnane with methyl substitution at the 5- and 14-carbon positions. The distribution of these compounds parallels that of the higher molecular weight diasteranes. A well-defined relationship is evident between the ratio Fe/S and short-chain diasterane content: samples with Fe/S approximately diasterane contents, while those with Fe/S approximately >0.90 exhibit high diasterane content. This threshold Fe/S value is nearly equal to the value associated with stoichiometric pyrite (0.87) and suggests that the abundance of short-chain diasteranes is related to excess iron associated with detrital clays. This is consistent with the accepted mechanism of sterane rearrangement, which is thought to proceed via catalysis of clay minerals. In contrast to the higher molecular-weight diasteranes, which increase in abundance relative to other sterane isomers with increasing thermal maturation, the abundance of the rearranged short-chain compounds varies little relative to diginane or homodiginane in a maturity suite from the U. Devonian Duvernay Formation. Predicted stabilities based on computational chemistry agree with the observed distributions; diginane/diapregnane and homodiginane/homodiapregnane represent compound pairs with similar thermal stabilities. The relative invariance of short-chain sterane distributions with maturity suggest that these compounds may be

  6. PLANKTIC FORAMINIFERAL DIVERSITY: LOGISTIC GROWTH OVERPRINTED BY A VARYING ENVIRONMENT

    OpenAIRE

    Andrés L. Cárdenas-Rozo; Peter J. HARRIES

    2016-01-01

    Este estudio evalúa estadísticamente la relación entre el patrón de diversidad global de los foraminíferos planctónicos en el largo plazo (~170 Ma al Reciente) y los cuatro modelos de diversificación propuestos desde la rama de la paleobiología: (i) “Reina Roja” (Van Valen, 1973; Raup et al., 1973), (ii) remplazo pausado (Vrba, 1985; Brett y Baird, 1995), (iii) diversidad en equilibrio (Sepkoski, 1978; Rosenzweig, 1995), y (iv) el “crecimiento logístico complicado” (Alroy, 2010a). Nuestros re...

  7. PLANKTIC FORAMINIFERAL DIVERSITY: LOGISTIC GROWTH OVERPRINTED BY A VARYING ENVIRONMENT

    Directory of Open Access Journals (Sweden)

    Andrés L. CÁRDENAS-ROZO

    2016-01-01

    Full Text Available Este estudio evalúa estadísticamente la relación entre el patrón de diversidad global de los foraminíferos planctónicos en el largo plazo (~170 Ma al Reciente y los cuatro modelos de diversificación propuestos desde la rama de la paleobiología: (i “Reina Roja” (Van Valen, 1973; Raup et al., 1973, (ii remplazo pausado (Vrba, 1985; Brett y Baird, 1995, (iii diversidad en equilibrio (Sepkoski, 1978; Rosenzweig, 1995, y (iv el “crecimiento logístico complicado” (Alroy, 2010a. Nuestros resultados sugieren que la forma de este patrón global de diversidad y la inter-relación entre las tasas de extinción y originación de este grupo no corresponden con los primeros tres modelos anteriormente citados. Sin embargo, estos pueden ser explicados bajo el cuarto escenario. Consecuentemente, las dinámicas de diversidad (i.e. patrón de diversidad y tasas de extinción y originación de este grupo posiblemente son controladas por la combinación de la competencia interespecífica de los foraminíferos planctónicos y varios cambios ambientales tales como temperaturas globales marinas que pudieron impactar el número de nichos dentro de la capa superior de los océanos. Además, otros patrones globales de diversidad en el largo plazo han sido interpretados como el reflejo del modelo de crecimiento logístico complicado, lo que sugiere que la relación entre factores abióticos y bióticos tiene un carácter fundamental en los procesos evolutivos que han sucedido a lo largo de la historia de la vida.

  8. Multireceiver Acoustic Communications in Time-Varying Environments

    Science.gov (United States)

    2014-06-01

    Dept., Naval Postgraduate School, Monterey, California, 2007. [29] R. Cristi, “Wireless communications with Matlab and Simulink : IEEE802.16 (WiMax...AND CONTRIBUTION ..........................53 B. RECOMMENDATIONS FOR FURTHER WORK...................................53 APPENDIX A. MATLAB CODES...APPENDIX B. SIMULATION DIAGRAM ..............................................................61 A. SIMULINK DIAGRAM OF PROPOSED MODEL

  9. Does stellar mass assembly history vary with environment?

    CERN Document Server

    Hoyle, Ben; Verde, Licia

    2011-01-01

    Using the publicly available VESPA database of SDSS Data Release 7 spectra, we calculate the stellar Mass Weighted Age (hereafter MWA) as a function of local galaxy density and dark matter halo mass. We compare our results with semi-analytic models from the public Millennium Simulation. We find that the stellar MWA has a large scatter which is inherent in the data and consistent with that seen in semi-analytic models. The stellar MWA is consistent with being independent (to first order) with local galaxy density, which is also seen in semi-analytic models. As a function of increasing dark matter halo mass (using the SDSS New York Value Added Group catalogues), we find that the average stellar MWA for member galaxies increases, which is again found in semi-analytic models. Furthermore we use public dark matter Mass Accretion History (MAH) code calibrated on simulations, to calculate the dark matter Mass Weighted Age as a function of dark matter halo mass. In agreement with earlier analyses, we find that the st...

  10. The Value of Information for Populations in Varying Environments

    Science.gov (United States)

    Rivoire, Olivier; Leibler, Stanislas

    2011-04-01

    The notion of information pervades informal descriptions of biological systems, but formal treatments face the problem of defining a quantitative measure of information rooted in a concept of fitness, which is itself an elusive notion. Here, we present a model of population dynamics where this problem is amenable to a mathematical analysis. In the limit where any information about future environmental variations is common to the members of the population, our model is equivalent to known models of financial investment. In this case, the population can be interpreted as a portfolio of financial assets and previous analyses have shown that a key quantity of Shannon's communication theory, the mutual information, sets a fundamental limit on the value of information. We show that this bound can be violated when accounting for features that are irrelevant in finance but inherent to biological systems, such as the stochasticity present at the individual level. This leads us to generalize the measures of uncertainty and information usually encountered in information theory.

  11. Response of cotton, alfalfa, and cantaloupe to foliar-deposited salt in an arid environment. [Gossypium hirsumtum L. ; Medicago sativa L. ; Cucumis melo L

    Energy Technology Data Exchange (ETDEWEB)

    Hofmann, W.C.; Karpiscak, M.M.; Bartels, P.G.

    The cooling towers at the Palo Verde Nuclear Generating Station (PVNGS), located 80 km west of Phoenix, AZ, will release as estimated 2.1 Mg/d of particulates (primarily salts) into the atmosphere when the station is in full operation. The saline drift will disperse and settle onto agricultural fields surrounding the station. Field studies were conducted in 1983 to investigate the influence of foliar-applied saline aerosol on crop growth, foliar injury, and tissue elemental concentration on cotton (Gossypium hirsutum L.), alfalfa (medicago sativa L.), and cantaloupe (Cucumis melo L.) in an arid environment. The treatment aerosol solutions simulated treated wastewater effluent and included all essential plant nutrients and other elements, including trace concentrations of heavy metals. The treatments included unsprayed plots, and plots sprayed with salt solutions at 0 (distilled water), 8, 83, and 415 kg/(ha yr). The alfalfa received an additional 829 kg/(ha yr) treatment. The species were evaluated in separate experiments on Mohave clay loam and Sonoita sandy loam soils (Typic Haplargid) near Marana, AZ. Cotton treated with 415 kg/(ha yr) had significantly less chlorosis and tended to be slightly taller than the cotton in the unsprayed plots. The alfalfa treated at a rate of 829 kg/(ha yr) showed significantly more leaf margin necrosis than did the unsprayed alfalfa. In the cantaloupe, there were no visually apparent differences among salt treatments. Hand-harvested cotton plots had a significant reduction is seed cotton yield at the 415 kg/(ha yr) treatment. A similar though nonsignificant, trend towards reduced yield with increased salt treatment was observed in machine-harvested cotton plots.

  12. A multiproxy approach for the reconstruction of ancient continental environments. The case of the Mio-Pliocene deposits of the Granada Basin (southern Iberian Peninsula)

    Science.gov (United States)

    García-Alix, Antonio

    2015-08-01

    Palaeoenvironmental reconstructions from fossil mammals are based on the straightforward relationship between the environment and the mammal assemblage living in the area. However, in some cases the environmental variables estimated from mammals are biassed by local influences. The palaeoenvironmental reconstruction of the Granada Basin (southern Spain) based on carbon and oxygen isotopes from enamel rodent teeth is compared with the palaeoenvironmental data from small mammal assemblages. Estimated temperatures from both proxies coincide, in general terms: cold-temperate conditions during the latest Tortonian (~ 16 °C; cold-temperate climate), dry sub-tropical conditions during the Messinian (16.6 °C-22 °C), and dry sub-tropical conditions during the early Pliocene (16.6 °C-17.2 °C). Reconstructed humidity trends from both proxies only agree in the first part of the record, showing dry conditions during the Tortonian-Messinian boundary and an increase in humidity at the beginning of the Messinian. During the Messinian and earliest Pliocene, humidity trends in each proxy are frequently opposed: small mammal assemblages suggest a huge increase in humidity at the beginning of the Messinian, and a decreasing trend towards the Pliocene, whereas carbon isotopes from rodent teeth suggest moderate humidity conditions during the Messinian. It can be concluded that physical changes in the landscape would affect taxa with high dependence on humid conditions, and they are more likely to record local environmental humidity changes rather than regional or global humidity ones. However, the past reconstructions of temperatures are not biassed by this effect, as the general temperature trends deduced from the faunal assemblages as well as those deduced from the isotopic approaches coincide. The general climatic trends reconstructed from isotopic analyses in small mammal teeth agree with the general environmental change in the western Mediterranean region as well as with the

  13. Iron-sulfide crystals in probe deposits

    DEFF Research Database (Denmark)

    Laursen, Karin; Frandsen, Flemming

    1998-01-01

    Iron-sulfides were observed in deposits collected on a probe inserted at the top of the furnace of a coal-fired power station in Denmark. The chemical composition of the iron-sulfides is equivalent to pyrrhotite (FeS). The pyrrhotites are present as crystals and, based on the shape of the crystals......, it was deduced that they were not deposited but instead grew within the deposit. The presence of unburned char particles within the deposits supports the concept that a reducing environment existed in the deposits. Two processes are proposed for explaining the existence of pyrrhotite crystals within a deposit...

  14. METALS DEPOSITS

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    <正>20090243 Chen Zhibin (Hebei Institute of Geological Survey, Shijiazhuang 050081, China) Ore-Controlling Factors of the Beichagoumen Ag-Polymetallic Deposits in Northern Hebei Province (Geological Survey and Research, ISSN1672-4135, CN12-1353/P, 31(1), 2008, p.1-5, 3 illus., 10 refs.)

  15. METALS DEPOSITS

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    <正>20131565 Cai Lianyou(No.332 Geological Team,Bureau of Geology and Mineral Resources Exploration of Anhui Province,Huangshan 245000,China);Weng Wangfei Geological Characteristics and Genesis Analysis of Guocun Navajoite Deposit in South Anhui Province(Mineral Resources and Geology,

  16. METALS DEPOSITS

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    <正>20102341 Bao Peisheng(Institute of Geology,Chinese Academy of Geological Science,Beijing 100037,China)Further Discussion on the Genesis of the Podiform Chromite Deposits in the Ophiolites-Questioning about the Rock:Melt Interaction Metallogeny(Geological Bulletin of China,ISSN1671-2552,CN11-4648/P,28(12),2009,p.1741-1761

  17. NONMETALS DEPOSITS

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    <正>20131601 Gao Junbo(College of Resources and Environmental Engineering,Guizhou University,Guiyang 550003,China);Yang Ruidong Hydrothermal Venting-Flowing Sedimentation Characteristics of Devonian Barite Deposits from Leji,Zhenning County,Guizhou Province(Acta Sedimentologica Sinica,ISSN1000-0550,CN62-1038/P,30(3),

  18. Varying c and Particle Horizons

    CERN Document Server

    Chimento, L P; Pavón, D; Chimento, Luis P; Jakubi, Alejandro S; Pavon, Diego

    2001-01-01

    We explore what restrictions may impose the second law of thermodynamics on varying speed of light theories. We find that the attractor scenario solving the flatness problem is consistent with the generalized second law at late time.

  19. Fundamental studies of growth mechanisms in physical vapour deposition of aluminium

    CERN Document Server

    Knorr, N J

    2000-01-01

    temperature could be independently controlled due to the low deposition rate of the aluminium. The depositions were performed in a UHV environment to ensure that film growth was not mediated by contamination. The ion energy range used was 10-75eV and the substrate temperature varied from -100 deg C to 200 deg C. The depositions were onto silicon (100) with a native oxide surface, except for a set of depositions which were performed on to silicon with the native oxide surface removed. The cleanliness of the depositions was verified using in-situ XPS analysis and after deposition the structure of the aluminium films was inferred from measurements using SEM, TEM, AFM XRD and Nano-indendation. This information allowed the mechanisms of growth of the aluminium films to be investigated. In addition to the extensive array of IBDR depositions a series of aluminium films were deposited using evaporation and sputtering. These films were grown at substrate temperatures between room temperate and 200 deg C. The use of ev...

  20. Trace and Rare Earth Element Characteristics in Fe-Mn Carbonates Associated with Stratiform Ag-Pb-Zn Mineraliza-tion from the Lengshuikeng Ore District, Jiangxi Province:Implications for Their Genesis and Depositional Environment

    Institute of Scientific and Technical Information of China (English)

    Qing Li; Shaoyong Jiang

    2016-01-01

    We performed a systematic trace and rare earth element analysis for the bedded Fe-Mn carbonate rocks related to the stratiform Ag-Pb-Zn mineralization in the Lengshuikeng ore district, Jiangxi Province, South China. Three types of Fe-Mn carbonates are distinguished, namely, the massive, breccia, and vein types. Both carbonate and silicate fractions in the samples are analyzed for their trace and rare earth element concentrations using a step acid-leaching technique. Our results show that the carbonate fractions in the massive type samples have the lowest REE concentrations but pronounced positive Eu and Y anomalies with Eu/Eu* value from 1.3 to 6.2 and Y/Ho value from 40.1 to 59.5, and similar characteristics are also shown for the silicate fractions in the massive type samples (Eu/Eu*=1.0–6.7, Y/Ho=20.7–55.1). These REE characteristics are similar to those of Sedex type mas-sive sulfide deposits worldwide, and we suggest that the massive type Fe-Mn carbonate rocks were likely formed from an exhalative volcanic-hydrothermal fluid feeding the depression basin of a volcanic lake. The high concentrations of redox-sensitive elements and ratios such as U/Th, V/Cr and V/(V+Ni) indicate a dysoxic environment for the Fe-Mn carbonate deposition. In contrast, the breccia type and vein type Fe-Mn carbonate samples show different trace and rare earth element features from those of massive type samples, and they are more similar to the volcanic rocks and magmatic-hydrothermal fluids in the Lengshuikeng ore district and may reflect strong overprinting from volcanic and sub-volcanic magmatism related to the porphyry type mineralization in the district.

  1. High Temperature Multilayer Environmental Barrier Coatings Deposited Via Plasma Spray-Physical Vapor Deposition

    Science.gov (United States)

    Harder, Bryan James; Zhu, Dongming; Schmitt, Michael P.; Wolfe, Douglas E.

    2014-01-01

    Si-based ceramic matrix composites (CMCs) require environmental barrier coatings (EBCs) in combustion environments to avoid rapid material loss. Candidate EBC materials have use temperatures only marginally above current technology, but the addition of a columnar oxide topcoat can substantially increase the durability. Plasma Spray-Physical Vapor Deposition (PS-PVD) allows application of these multilayer EBCs in a single process. The PS-PVD technique is a unique method that combines conventional thermal spray and vapor phase methods, allowing for tailoring of thin, dense layers or columnar microstructures by varying deposition conditions. Multilayer coatings were deposited on CMC specimens and assessed for durability under high heat flux and load. Coated samples with surface temperatures ranging from 2400-2700F and 10 ksi loads using the high heat flux laser rigs at NASA Glenn. Coating morphology was characterized in the as-sprayed condition and after thermomechanical loading using electron microscopy and the phase structure was tracked using X-ray diffraction.

  2. Martian Hot Springs? Silica deposits in the Nili Patera Caldera.

    Science.gov (United States)

    Skok, J. R.; Mustard, J. F.; Ehlmann, B. L.; Murchie, S. L.

    2011-12-01

    detected just west of the cone center near it's apex and appears to be exposed outcrop. The remaining detections are quasi-circular mounds on the caldera floor. One isolated large deposit is at the southern edge of the cone while the majority of deposits are in an 8,000 km2 field directly southwest of the cone that contains dozens of deposits of varying sizes. Recently confirmed deposits are also located in the far field, 10 km to the southwest of the cone but still confined to the dacite lava flow. These show that the deposits are more widespread than the immediate vicinity of the volcanic cone. This volcanically driven hydrothermal system and the resulting hot spring environments on Mars has significance for our understanding of Martian volcanic systems and for the search for habitability. Terrestrial hot springs are known to be ideal locations for microbial activity and for the sequestration and long-term preservation of biosignatures . Hot spring silica sinter deposits are among the best materials for preserving signs of habitability making the Nili Patera deposits an ideal location for future focused study.

  3. Time-varying Crash Risk

    DEFF Research Database (Denmark)

    Christoffersen, Peter; Feunoua, Bruno; Jeon, Yoontae

    We estimate a continuous-time model with stochastic volatility and dynamic crash probability for the S&P 500 index and find that market illiquidity dominates other factors in explaining the stock market crash risk. While the crash probability is time-varying, its dynamic depends only weakly on re...

  4. Time-varying Crash Risk

    DEFF Research Database (Denmark)

    Christoffersen, Peter; Feunoua, Bruno; Jeon, Yoontae

    We estimate a continuous-time model with stochastic volatility and dynamic crash probability for the S&P 500 index and find that market illiquidity dominates other factors in explaining the stock market crash risk. While the crash probability is time-varying, its dynamic depends only weakly...... on return variance once we include market illiquidity as an economic variable in the model....

  5. Esmaklassiline Karlovy Vary / Jaanus Noormets

    Index Scriptorium Estoniae

    Noormets, Jaanus

    2007-01-01

    Ilmar Raagi mängufilm "Klass" võitis 42. Karlovy Vary rahvusvahelise filmifestivalil kaks auhinda - ametliku kõrvalvõistlusprogrammi "East of the West" eripreemia "Special mention" ja Euroopa väärtfilmikinode keti Europa Cinemas preemia. Ka Asko Kase lühifilmi "Zen läbi prügi linastumisest ning teistest auhinnasaajatest ning osalejatest

  6. Optimistlik Karlovy Vary / Jaan Ruus

    Index Scriptorium Estoniae

    Ruus, Jaan, 1938-2017

    2007-01-01

    42. Karlovy Vary rahvusvahelise filmifestivali auhinnatud filmidest (žürii esimees Peter Bart). Kristallgloobuse sai Islandi-Saksamaa "Katseklaasilinn" (režii Baltasar Kormakur), parimaks režissööriks tunnistati norralane Bard Breien ("Negatiivse mõtlemise kunst"). Austraallase Michael James Rowlandi "Hea õnne teekond" sai žürii eripreemia

  7. Eestlased Karlovy Varys / J. R.

    Index Scriptorium Estoniae

    J. R.

    2007-01-01

    Ilmar Raagi mängufilm "Klass" osaleb 42. Karlovy Vary rahvusvahelise filmifestivali võistlusprogrammis "East of the West" ja Asko Kase lühimängufilm "Zen läbi prügi" on valitud festivali kõrvalprogrammi "Forum of Independents"

  8. Esmaklassiline Karlovy Vary / Jaanus Noormets

    Index Scriptorium Estoniae

    Noormets, Jaanus

    2007-01-01

    Ilmar Raagi mängufilm "Klass" võitis 42. Karlovy Vary rahvusvahelise filmifestivalil kaks auhinda - ametliku kõrvalvõistlusprogrammi "East of the West" eripreemia "Special mention" ja Euroopa väärtfilmikinode keti Europa Cinemas preemia. Ka Asko Kase lühifilmi "Zen läbi prügi linastumisest ning teistest auhinnasaajatest ning osalejatest

  9. METALS DEPOSITS

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    <正>20122389 Cai Lianyou ( No.332 Geological Team,Bureau of Geology and Mineral Resources Exploration of Anhui Province,Huangshan 245000,China );Weng Wangfei Geologic Characteristic and Ore-Control Factors of the Nanshan W-Mo Polymetallic Ore Deposit in South Anhui Province ( Geological Survey and Research,ISSN1672-4135,CN12-1353 / P,34 ( 4 ), 2011,p.290-298,3 illus.,1table,14refs. ) Key words:tungsten ores,molybdenum ores,ore guide of prospecting,Anhui Province

  10. METALS DEPOSITS

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    <正>20110165 Chen Jiawei(The 3rd Geological Team,Henan Bureau of Geology and Mineral Resources,Xinyang 464000,China)Ore Control Conditions and Genetic Model for the Bodaoling Ag-Au Deposit in Guangshan,Henan Province(Acta Geologica Sichuan,ISSN1006-0995,CN51-1273/P,30(1),2010,p.28-30,5 illus.,1 ref.,with English abstract)Key words:gold ores,Henan Province20110166 Chen Mingquan(Geological Team 306,Yunnan Bureau of Nonferrous Geology,Kunming 650216,Ch

  11. 碳纳米管在水溶液中的聚集和沉降行为研究%The aggregation and deposition of carbon nanotubes in aquatic environment

    Institute of Scientific and Technical Information of China (English)

    周丽霞; 张淑娟; 潘丙才

    2014-01-01

    As a novel nanoscale carbonaceous materials,carbon nanotubes(CNTs)have attracted extensive interests. Due to their unique electronic,optical,thermal,and mechanical properties,CNTs have been an ideal materials for industrial application.The ever rising demand and the decreasing cost lead to increased release of CNTs into natural waters.Once exposed to water environment,owing to their large specific surface areas,CNTs will inevitably adsorb the coexsited organic contaminations.Due to their nanoscale,CNTs are easily penetrated into human body,thus becoming a latent threat to both the environment and human being.The bioavailability and the toxicity of CNTs largely depend on their particle size in aquatic environment.In other words,the dispersion stability of CNTs is a key factor in determining their transport and fate in aquatic environment.Therefore,studies on the aggregation and deposition behavior of CNTs is of great significance to predict their environmental effects on water bodies.In this review,the mechanisms for the aggregation and deposition behaviors of CNTs were elucidated by describing the in-teractions between CNT colloidals with the classical Derjaguin-Landau-Verwey-Overbeek(DLVO)theory and the non-DLVO forces.The aggregation and deposition kinetics of CNTs were probed with the aid of time-resolved dynamic light scattering,quartz crystal microbalance,and column filtration analysis.The effects of some influencing factors,such as the physiochemical properties of CNTs(diameter,length,the content of surface functional groups), ionic strength,solution pH,and natural organic matters,on the dispersion stability of CNTs were evaluated. Moreover,the main difficulties in the study of the aggregation and deposition behavior of CNTs were pointed out. The complexity of matters in natural water and the lack of suitable experimental approach aggravated the difficulties in the current investigation on CNTs.The possible development of experimental research on CNTs in the

  12. Enhanced nitrogen deposition over China

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xuejun; Zhang, Ying; Han, Wenxuan; Tang, Aohan; Shen, Jianlin; Cui, Zhenling; Christie, Peter; Zhang, Fusuo [College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193 (China); Vitousek, Peter [Department of Biology, Stanford University, Stanford, California 94305 (United States); Erisman, Jan Willem [VU University Amsterdam, 1081 HV Amsterdam (Netherlands); Goulding, Keith [The Sustainable Soils and Grassland Systems Department, Rothamsted Research, Harpenden AL5 2JQ (United Kingdom); Fangmeier, Andreas [Institute of Landscape and Plant Ecology, University of Hohenheim, 70593 Stuttgart (Germany)

    2013-02-28

    China is experiencing intense air pollution caused in large part by anthropogenic emissions of reactive nitrogen. These emissions result in the deposition of atmospheric nitrogen (N) in terrestrial and aquatic ecosystems, with implications for human and ecosystem health, greenhouse gas balances and biological diversity. However, information on the magnitude and environmental impact of N deposition in China is limited. Here we use nationwide data sets on bulk N deposition, plant foliar N and crop N uptake (from long-term unfertilized soils) to evaluate N deposition dynamics and their effect on ecosystems across China between 1980 and 2010. We find that the average annual bulk deposition of N increased by approximately 8 kilograms of nitrogen per hectare (P < 0.001) between the 1980s (13.2 kilograms of nitrogen per hectare) and the 2000s (21.1 kilograms of nitrogen per hectare). Nitrogen deposition rates in the industrialized and agriculturally intensified regions of China are as high as the peak levels of deposition in northwestern Europe in the 1980s, before the introduction of mitigation measures. Nitrogen from ammonium (NH4+) is the dominant form of N in bulk deposition, but the rate of increase is largest for deposition of N from nitrate (NO3-), in agreement with decreased ratios of NH3 to NOx emissions since 1980. We also find that the impact of N deposition on Chinese ecosystems includes significantly increased plant foliar N concentrations in natural and semi-natural (that is, non-agricultural) ecosystems and increased crop N uptake from long-term-unfertilized croplands. China and other economies are facing a continuing challenge to reduce emissions of reactive nitrogen, N deposition and their negative effects on human health and the environment.

  13. sedimentology, depositional environments and basin evolution of ...

    African Journals Online (AJOL)

    Preferred Customer

    The Delbi-Moye Basin consists of two sedimentary units (upper and lower sedimentary ... alluvial fan, fluviatile, off shore lacustrine, shoreline lacustrine and paludal and/or swampy depositonal .... Lower mudstone, gravely sandstone and sandy con- glomerates ...... Alluvial sand- stone composition and palaeoclimate: I.

  14. Stable-isotope geochemistry of the Pierina high-sulfidation Au-Ag deposit, Peru: Influence of hydrodynamics on SO42--H2S sulfur isotopic exchange in magmatic-steam and steam-heated environments

    Science.gov (United States)

    Fifarek, R.H.; Rye, R.O.

    2005-01-01

    environment was unusually slow, which provided sufficient time for the uptake of groundwater and partial to complete SO42--H2S isotopic exchange. The slow steam velocities were likely related to the dispersal of the steam column as it entered the tuffs and possibly to intermediate exsolution rates from magmatic brine. The low ??D values may also partly reflect continuous degassing of the mineralizing magma. Similarly, data for steam-heated alunite (??34S=12.3??? to 27.2???; ??18OSO4=11.7??? to 13.0???; ??18OOH=6.6??? to 9.4???; ??D=-59??? to -42???) are unusual and indicate a strong magmatic influence, relatively high temperatures (140 to 180 ??C, based on ??18 OSO4-OH fractionations), and partial to complete sulfur isotopic exchange between steam-heated sulfate and H2S. Restricted lithologically controlled fluid flow in the host tuffs allowed magmatic condensate to supplant meteoric groundwater at the water table and create the high-temperature low-pH conditions that permitted unusually rapid SO42--H2S isotopic equilibration (50-300 days) and (or) long sulfate residence times for this environment. Late void-filling barite (??34S=7.4??? to 29.7???; ??18OSO4=-0.4??? to 15.1???) and later void-filling goethite (??18O=-11.8??? to 0.2???) document a transition from magmatic condensate to dominantly meteoric water in steam-heated fluids during cooling and collapse of the hydrothermal system. These steam-heated fluids oxidized the top ???300 m of the deposit by leaching sulfides, redistributing metals, and precipitating barite??acanthite??gold and goethite-hematite ??gold. Steam-heated oxidation, rather than weathering, was critical to forming the orebody in that it not only released encapsulated gold but likely enriched the deposit to ore-grade Au concentrations. ?? 2004 Elsevier B.V. All rights reserved.

  15. Mesoproterozoic graphite deposits, New Jersey Highlands: Geologic and stable isotopic evidence for possible algal origins

    Science.gov (United States)

    Volkert, R.A.

    2000-01-01

    Graphite deposits of Mesoproterozoic age are locally abundant in the eastern New Jersey Highlands, where they are hosted by sulphidic biotite-quartz-feldspar gneiss, metaquartzite, and anatectic pegmatite. Gneiss and metaquartzite represent a shallow marine shelf sequence of locally organic-rich sand and mud. Graphite from massive deposits within metaquartzite yielded ??13C values of -26 ?? 2??? (1??), and graphite from massive deposits within biotite-quartz-feldspar gneiss yielded ??13C values of -23 ??4???. Disseminated graphite from biotite-quartz-feldspar gneiss country rock was -22 ??3???, indistinguishable from the massive deposits hosted by the same lithology. Anatectic pegmatite is graphitic only where generated from graphite-bearing host rocks; one sample gave a ??13C value of -15???. The ??34S values of trace pyrrhotite are uniform within individual deposits, but vary from 0 to 9??? from one deposit to another. Apart from pegmatitic occurrences, evidence is lacking for long-range mobilization of carbon during Grenvillian orogenesis or post-Grenvillian tectonism. The field, petrographic, and isotope data suggest that massive graphite was formed by granulite-facies metamorphism of Proterozoic accumulations of sedimentary organic matter, possibly algal mats. Preservation of these accumulations in the sedimentary environment requires anoxic basin waters or rapid burial. Anoxia would also favour the accumulation of dissolved ferrous iron in basin waters, which may explain some of the metasediment-hosted massive magnetite deposits in the New Jersey Highlands. ?? 2000 NRC.

  16. Atmospheric wet and dry deposition of trace elements at 10 sites in Northern China

    Science.gov (United States)

    Pan, Y. P.; Wang, Y. S.

    2015-01-01

    Atmospheric deposition is considered to be a major process that removes pollutants from the atmosphere and an important source of nutrients and contaminants for ecosystems. Trace elements (TEs), especially toxic metals deposited on plants and into soil or water, can cause substantial damage to the environment and human health due to their transfer and accumulation in food chains. Despite public concerns, quantitative knowledge of metal deposition from the atmosphere to ecosystems remains scarce. To advance our understanding of the spatiotemporal variations in the magnitudes, pathways, compositions and impacts of atmospherically deposited TEs, precipitation (rain and snow) and dry-deposited particles were collected simultaneously at 10 sites in Northern China from December 2007 to November 2010. The measurements showed that the wet and dry depositions of TEs in the target areas were orders of magnitude higher than previous observations within and outside China, generating great concern over the potential risks. The spatial distribution of the total (wet plus dry) deposition flux was consistent with that of the dry deposition, with a significant decrease from industrial and urban areas to suburban, agricultural and rural sites, while the wet deposition exhibited less spatial variation. In addition, the seasonal variation of wet deposition was also different from that of dry deposition, although they were both governed by the precipitation and emission patterns. For the majority of TEs that exist as coarse particles, dry deposition dominated the total flux at each site. This was not the case for potassium, nickel, arsenic, lead, zinc, cadmium, selenium, silver and thallium, for which the relative importance between wet and dry deposition fluxes varied by site. Whether wet deposition is the major atmospheric cleansing mechanism for the TEs depends on the size distribution of the particles. We found that atmospheric inputs of copper, lead, zinc, cadmium, arsenic and

  17. METALS DEPOSITS

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    20152394 Cao Jun(State Key Laboratory of Petroleum Resources and Prospecting,China University of Petroleum,Beijing 102249,China);Zhong Ningning Geochemical Characteristics,Origin and Factors Controlling Formation of Marine Source Rock in Lower Congo Basin(Journal of Earth Sciences and Environment,ISSN1672-6561,CN61-1423/P,36

  18. Time distribution of the main Brazilian mineral deposits. 2: metallogenic epochs; Distribuicao no tempo geologico dos principais depositos minerais brasileiros. 2: epocas metalogeneticas

    Energy Technology Data Exchange (ETDEWEB)

    Biondi, Joao C. [Parana Univ., Curitiba, PR (Brazil). Dept. de Geologia]. E-mail: jcbiondi@setuva.geologia.ufpr.br

    1999-12-01

    The metallogenic epochs of the main mineral deposit groups were defined with base on the ore's of the 194 main Brazilian mineral deposits. Mineral deposits are rare on epochs that: precede the beginning of juvenile accretion peak periods, and/or of cooling of rocks formed during each of the main brazilian thermo-tectonic events. Deposits are more frequent on epochs that are coincident or immediately younger than these peak periods. The most important metallogenic epoch, with about 30% of the selected deposits, is between 50 Ma and the Recent, and corresponds to the formation of supergenic and/or residual and placer deposits. Brazilian's volcanogenic (VHMS), Mississippi Valley (MTV) and mesothermal gold-lode deposits have discordant ages as compared with their equivalents in other countries, while deposits believed to be SEDEX have concordant ages. With the exception of Urucum, the primary iron and manganese ores of brazilian deposits are Archean. Primary tin deposits from Amazonas, Amapa and Goias State cluster between 1500 and 2300 Ma. Tin deposits from Rondonia and Mato Grosso are more recent and most formed between 1000 and 1600 Ma, in sequence with the other groups of tin deposits. Uranium deposits vary on genetic model and ages, due to the mobility of the element in all geologic environments. Most part of Brazilian deposits of phosphate, titanium, niobium, Rare Earths, diamond in kimberlites and of amethyst formed during the Mesozoic, and arte genetically related to the alkaline and basaltic magmatism that affected the brazilian territory in this period. Gemstone (tourmaline and aquamarine), talc and magnesite deposits are more frequent in the Brasiliano period. Gipsite, silvite and barite occur in Senonian to Aptian evaporites. (author)

  19. In-flow evolution of lahar deposits from video-imagery with implications for post-event deposit interpretation, Mount Semeru, Indonesia

    Science.gov (United States)

    Starheim, Colette C. A.; Gomez, Christopher; Davies, Tim; Lavigne, Franck; Wassmer, Patrick

    2013-04-01

    The hazardous and unpredictable nature of lahars makes them challenging to study, yet the in-flow processes characterizing these events are important to understand. As a result, much of the previous research on lahar sedimentation and flow processes has been derived from experimental flows or stratigraphic surveys of post-event deposits. By comparison, little is known on the time-dependent sediment and flow dynamics of lahars in natural environments. Using video-footage of seven lahars on the flanks of Semeru Volcano (East Java, Indonesia), the present study offers new insights on the in-flow evolution of sediment in natural lahars. Video analysis revealed several distinctive patterns of sediment entrainment and deposition that varied with time-related fluctuations in flow. These patterns were used to generate a conceptual framework describing possible processes of formation for subsurface architectural features identified in an earlier lateral survey of lahar deposits on Semeru Volcano (Gomez and Lavigne, 2010a). The formation of lateral discontinuities was related to the partial erosion of transitional bank deposits followed by fresh deposition along the erosional contact. This pattern was observed over the course of several lahar events and within individual flows. Observations similarly offer potential explanations for the formation of lenticular features. Depending on flow characteristics, these features appeared to form by preferential erosion or deposition around large stationary blocks, and by deposition along channel banks during episodes of channel migration or channel constriction. Finally, conditions conducive to the deposition of fine laminated beds were observed during periods of attenuating and surging flow. These results emphasize the difficulties associated with identifying process-structure relationships solely from post-event deposit interpretation and illustrate that an improved understanding of the time-dependent sediment dynamics in lahars may

  20. NONMETALS DEPOSITS

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    20152443 Cai Yitao(Nanjing Institute of Geology and Mineral Resources,Nanjing 210016,China);Chen Guoguang Geochemical Features of the Olivine-Gabbros and Their Relationship with Diamond-Mineralization in the Langan Area,Anhui Province(Resources Survey&Environment,ISSN1671-4814,CN32-1640/N,35(4),2014,p.245-253,10illus.,3tables,44 refs.)

  1. Deposition and Resuspension of Particles

    DEFF Research Database (Denmark)

    Lengweiler, P.; Nielsen, Peter V.; Moser, A.

    To investigate the physical process of deposition and resuspension of particles in the indoor environment, scale experiments are used and a sampling method is established. The influences of surface orientation and turbulence and velocity of the air on the dust load on a surface are analysed....

  2. Harmonic functions with varying coefficients

    Directory of Open Access Journals (Sweden)

    Jacek Dziok

    2016-05-01

    Full Text Available Abstract Complex-valued harmonic functions that are univalent and sense preserving in the open unit disk can be written in the form f = h + g ‾ $f=h+\\overline{g}$ , where h and g are analytic. In this paper we investigate some classes of univalent harmonic functions with varying coefficients related to Janowski functions. By using the extreme points theory we obtain necessary and sufficient convolution conditions, coefficients estimates, distortion theorems, and integral mean inequalities for these classes of functions. The radii of starlikeness and convexity for these classes are also determined.

  3. Linearized Bekenstein Varying Alpha Models

    CERN Document Server

    Pina-Avelino, P; Oliveira, J C

    2004-01-01

    We study the simplest class of Bekenstein-type, varying $\\alpha$ models, in which the two available free functions (potential and gauge kinetic function) are Taylor-expanded up to linear order. Any realistic model of this type reduces to a model in this class for a certain time interval around the present day. Nevertheless, we show that no such model is consistent with all existing observational results. We discuss possible implications of these findings, and in particular clarify the ambiguous statement (often found in the literature) that ``the Webb results are inconsistent with Oklo''.

  4. Linearized Bekenstein varying α models

    Science.gov (United States)

    Avelino, P. P.; Martins, C. J.; Oliveira, J. C.

    2004-10-01

    We study the simplest class of Bekenstein-type, varying α models, in which the two available free functions (potential and gauge kinetic function) are Taylor-expanded up to linear order. Any realistic model of this type reduces to a model in this class for a certain time interval around the present day. Nevertheless, we show that no such model is consistent with all existing observational results. We discuss possible implications of these findings, and, in particular, clarify the ambiguous statement (often found in the literature) that “the Webb results are inconsistent with Oklo.”

  5. Time-varying cosmological term

    Science.gov (United States)

    Socorro, J.; D'oleire, M.; Pimentel, Luis O.

    2015-11-01

    We present the case of time-varying cosmological term using the Lagrangian formalism characterized by a scalar field ϕ with standard kinetic energy and arbitrary potential V(ϕ). This model is applied to Friedmann-Robertson-Walker (FRW)cosmology. Exact solutions of the field equations are obtained by a special ansats to solve the Einstein-Klein-Gordon equation and a particular potential for the scalar field and barotropic perfect fluid. We present the evolution on this cosmological term with different scenarios.

  6. A depositional model for organic-rich Duvernay Formation mudstones

    Science.gov (United States)

    Knapp, Levi J.; McMillan, Julia M.; Harris, Nicholas B.

    2017-01-01

    The Upper Devonian Duvernay Formation of western Canada is an organic-rich shale formation now targeted as a hydrocarbon reservoir. We present a detailed sedimentological analysis of the Duvernay Formation in order to better understand organic-rich mudstone depositional processes and conditions and to characterize the vertical and lateral heterogeneity of mudstone lithofacies that affect petrophysical and geomechanical rock properties. Organic-rich mudstone facies of the Duvernay Formation were deposited in a dynamic depositional environment by a variety of sediment transport mechanisms, including suspension settling, turbidity currents, and bottom water currents in variably oxygenated bottom waters. Suspension settling dominated in distal relatively deep areas of the basin, but evidence for weak turbidity currents and bottom water currents was observed in the form of graded beds and thin grain-supported siltstone laminae. Organic enrichment primarily occurred in distal areas as a result of bottom water anoxia and low depositional rates of inorganic sediment. In deep water locations near platform margins, alternating silty-sandy contourite beds and organic-rich mudstone beds are present, the former interpreted to have been deposited and reworked by bottom water currents flowing parallel to slope. In shallower, more oxygenated settings, mudstone lithologies vary from calcareous to argillaceous. These sediments were deposited from suspension settling, turbidity currents, and bottom water currents, although primary sedimentary structures are often obscured by extensive bioturbation. Locally, organic enrichment in dysoxic rather than anoxic bottom waters was driven by a slightly increased sedimentation rate and possibly also by aggregation of sedimentary particles in the water column due to interaction between organic matter and clay minerals. Large variations observed in sediment composition, from siliceous to calcareous to argillaceous, reflect multiple biogenic

  7. Varying Constants, Gravitation and Cosmology

    Directory of Open Access Journals (Sweden)

    Jean-Philippe Uzan

    2011-03-01

    Full Text Available Fundamental constants are a cornerstone of our physical laws. Any constant varying in space and/or time would reflect the existence of an almost massless field that couples to matter. This will induce a violation of the universality of free fall. Thus, it is of utmost importance for our understanding of gravity and of the domain of validity of general relativity to test for their constancy. We detail the relations between the constants, the tests of the local position invariance and of the universality of free fall. We then review the main experimental and observational constraints that have been obtained from atomic clocks, the Oklo phenomenon, solar system observations, meteorite dating, quasar absorption spectra, stellar physics, pulsar timing, the cosmic microwave background and big bang nucleosynthesis. At each step we describe the basics of each system, its dependence with respect to the constants, the known systematic effects and the most recent constraints that have been obtained. We then describe the main theoretical frameworks in which the low-energy constants may actually be varying and we focus on the unification mechanisms and the relations between the variation of different constants. To finish, we discuss the more speculative possibility of understanding their numerical values and the apparent fine-tuning that they confront us with.

  8. Varying Constants, Gravitation and Cosmology.

    Science.gov (United States)

    Uzan, Jean-Philippe

    2011-01-01

    Fundamental constants are a cornerstone of our physical laws. Any constant varying in space and/or time would reflect the existence of an almost massless field that couples to matter. This will induce a violation of the universality of free fall. Thus, it is of utmost importance for our understanding of gravity and of the domain of validity of general relativity to test for their constancy. We detail the relations between the constants, the tests of the local position invariance and of the universality of free fall. We then review the main experimental and observational constraints that have been obtained from atomic clocks, the Oklo phenomenon, solar system observations, meteorite dating, quasar absorption spectra, stellar physics, pulsar timing, the cosmic microwave background and big bang nucleosynthesis. At each step we describe the basics of each system, its dependence with respect to the constants, the known systematic effects and the most recent constraints that have been obtained. We then describe the main theoretical frameworks in which the low-energy constants may actually be varying and we focus on the unification mechanisms and the relations between the variation of different constants. To finish, we discuss the more speculative possibility of understanding their numerical values and the apparent fine-tuning that they confront us with.

  9. Varying Constants, Gravitation and Cosmology

    Science.gov (United States)

    Uzan, Jean-Philippe

    2011-12-01

    Fundamental constants are a cornerstone of our physical laws. Any constant varying in space and/or time would reflect the existence of an almost massless field that couples to matter. This will induce a violation of the universality of free fall. Thus, it is of utmost importance for our understanding of gravity and of the domain of validity of general relativity to test for their constancy. We detail the relations between the constants, the tests of the local position invariance and of the universality of free fall. We then review the main experimental and observational constraints that have been obtained from atomic clocks, the Oklo phenomenon, solar system observations, meteorite dating, quasar absorption spectra, stellar physics, pulsar timing, the cosmic microwave background and big bang nucleosynthesis. At each step we describe the basics of each system, its dependence with respect to the constants, the known systematic effects and the most recent constraints that have been obtained. We then describe the main theoretical frameworks in which the low-energy constants may actually be varying and we focus on the unification mechanisms and the relations between the variation of different constants. To finish, we discuss the more speculative possibility of understanding their numerical values and the apparent fine-tuning that they confront us with.

  10. Strontium-Doped Lanthanum Manganite Films Prepared by Magnetic Deposition

    DEFF Research Database (Denmark)

    Menon, Mohan; Larsen, Casper; Andersen, Kjeld Bøhm

    2009-01-01

    Deposition of La0.85Sr0.15MnO3 (LSM) films from suspensions using a magnetic field was found to be a cheap and quick technique. Ninety weight percent of the particles present in the suspensions were deposited within the first minute of the deposition, and the thickness of the film varied linearly...

  11. Local Varying-Alpha Theories

    CERN Document Server

    Barrow, John D

    2014-01-01

    In a recent paper we demonstrated how the simplest model for varying alpha may be interpreted as the effect of a dielectric material, generalized to be consistent with Lorentz invariance. Unlike normal dielectrics, such a medium cannot change the speed of light, and its dynamics obey a Klein-Gordon equation. This work immediately suggests an extension of the standard theory, even if we require compliance with Lorentz invariance. Instead of a wave equation, the dynamics may satisfy a local algebraic relation involving the permittivity and the properties of the electromagnetic field, in analogy with more conventional dielectric (but still preserving Lorentz invariance). We develop the formalism for such theories and investigate some phenomenological implications. The problem of the divergence of the classical self-energy can be solved, or at least softened, in this framework. Some interesting new cosmological solutions for the very early universe are found, including the possibility of a bounce, inflation and e...

  12. Varying constants, Gravitation and Cosmology

    CERN Document Server

    Uzan, Jean-Philippe

    2010-01-01

    Fundamental constants are a cornerstone of our physical laws. Any constant varying in space and/or time would reflect the existence of an almost massless field that couples to matter. This will induce a violation of the universality of free fall. It is thus of utmost importance for our understanding of gravity and of the domain of validity of general relativity to test for their constancy. We thus detail the relations between the constants, the tests of the local position invariance and of the universality of free fall. We then review the main experimental and observational constraints that have been obtained from atomic clocks, the Oklo phenomenon, Solar system observations, meteorites dating, quasar absorption spectra, stellar physics, pulsar timing, the cosmic microwave background and big bang nucleosynthesis. At each step we describe the basics of each system, its dependence with respect to the constants, the known systematic effects and the most recent constraints that have been obtained. We then describ...

  13. Exploration of Periodically Varying Graphs

    CERN Document Server

    Flocchini, Paola; Santoro, Nicola

    2009-01-01

    We study the computability and complexity of the exploration problem in a class of highly dynamic graphs: periodically varying (PV) graphs, where the edges exist only at some (unknown) times defined by the periodic movements of carriers. These graphs naturally model highly dynamic infrastructure-less networks such as public transports with fixed timetables, low earth orbiting (LEO) satellite systems, security guards' tours, etc. We establish necessary conditions for the problem to be solved. We also derive lower bounds on the amount of time required in general, as well as for the PV graphs defined by restricted classes of carriers movements: simple routes, and circular routes. We then prove that the limitations on computability and complexity we have established are indeed tight. In fact we prove that all necessary conditions are also sufficient and all lower bounds on costs are tight. We do so constructively presenting two worst case optimal solution algorithms, one for anonymous systems, and one for those w...

  14. Time-Varying Fundamental Constants

    Science.gov (United States)

    Olive, Keith

    2003-04-01

    Recent data from quasar absorption systems can be interpreted as arising from a time variation in the fine-structure constant. However, there are numerous cosmological, astro-physical, and terrestrial bounds on any such variation. These includes bounds from Big Bang Nucleosynthesis (from the ^4He abundance), the Oklo reactor (from the resonant neutron capture cross-section of Sm), and from meteoretic lifetimes of heavy radioactive isotopes. The bounds on the variation of the fine-structure constant are significantly strengthened in models where all gauge and Yukawa couplings vary in a dependent manner, as would be expected in unified theories. Models which are consistent with all data are severly challenged when Equivalence Principle constraints are imposed.

  15. Weighted approximation with varying weight

    CERN Document Server

    Totik, Vilmos

    1994-01-01

    A new construction is given for approximating a logarithmic potential by a discrete one. This yields a new approach to approximation with weighted polynomials of the form w"n"(" "= uppercase)P"n"(" "= uppercase). The new technique settles several open problems, and it leads to a simple proof for the strong asymptotics on some L p(uppercase) extremal problems on the real line with exponential weights, which, for the case p=2, are equivalent to power- type asymptotics for the leading coefficients of the corresponding orthogonal polynomials. The method is also modified toyield (in a sense) uniformly good approximation on the whole support. This allows one to deduce strong asymptotics in some L p(uppercase) extremal problems with varying weights. Applications are given, relating to fast decreasing polynomials, asymptotic behavior of orthogonal polynomials and multipoint Pade approximation. The approach is potential-theoretic, but the text is self-contained.

  16. TULSA UNIVERSITY PARAFFIN DEPOSITION PROJECTS

    Energy Technology Data Exchange (ETDEWEB)

    Michael Volk; Cem Sarica

    2003-10-01

    As oil and gas production moves to deeper and colder water, subsea multiphase production systems become critical for economic feasibility. It will also become increasingly imperative to adequately identify the conditions for paraffin precipitation and predict paraffin deposition rates to optimize the design and operation of these multiphase production systems. Although several oil companies have paraffin deposition predictive capabilities for single-phase oil flow, these predictive capabilities are not suitable for the multiphase flow conditions encountered in most flowlines and wellbores. For deepwater applications in the Gulf of Mexico, it is likely that multiphase production streams consisting of crude oil, produced water and gas will be transported in a single multiphase pipeline to minimize capital cost and complexity at the mudline. Existing single-phase (crude oil) paraffin deposition predictive tools are clearly inadequate to accurately design these pipelines because they do not account for the second and third phases, namely, produced water and gas. The objective of this program is to utilize the current test facilities at The University of Tulsa, as well as member company expertise, to accomplish the following: enhance our understanding of paraffin deposition in single and two-phase (gas-oil) flows; conduct focused experiments to better understand various aspects of deposition physics; and, utilize knowledge gained from experimental modeling studies to enhance the computer programs developed in the previous JIP for predicting paraffin deposition in single and two-phase flow environments. These refined computer models will then be tested against field data from member company pipelines. The following deliverables are scheduled during the first three projects of the program: (1) Single-Phase Studies, with three different black oils, which will yield an enhanced computer code for predicting paraffin deposition in deepwater and surface pipelines. (2) Two

  17. Deposit model for volcanogenic uranium deposits

    Science.gov (United States)

    Breit, George N.; Hall, Susan M.

    2011-01-01

    Volcanism is a major contributor to the formation of important uranium deposits both close to centers of eruption and more distal as a result of deposition of ash with leachable uranium. Hydrothermal fluids that are driven by magmatic heat proximal to some volcanic centers directly form some deposits. These fluids leach uranium from U-bearing silicic volcanic rocks and concentrate it at sites of deposition within veins, stockworks, breccias, volcaniclastic rocks, and lacustrine caldera sediments. The volcanogenic uranium deposit model presented here summarizes attributes of those deposits and follows the focus of the International Atomic Energy Agency caldera-hosted uranium deposit model. Although inferred by some to have a volcanic component to their origin, iron oxide-copper-gold deposits with economically recoverable uranium contents are not considered in this model.

  18. Gait phase varies over velocities.

    Science.gov (United States)

    Liu, Yancheng; Lu, Kun; Yan, Songhua; Sun, Ming; Lester, D Kevin; Zhang, Kuan

    2014-02-01

    We sought to characterize the percent (PT) of the phases of a gait cycle (GC) as velocity changes to establish norms for pathological gait characteristics with higher resolution technology. Ninety five healthy subjects (49 males and 46 females with age 34.9 ± 11.8 yrs, body weight 64.0 ± 11.7 kg and BMI 23.5 ± 3.6) were enrolled and walked comfortably on a 10-m walkway at self-selected slower, normal, and faster velocities. Walking was recorded with a high speed camera (250 frames per second) and the eight phases of a GC were determined by examination of individual frames for each subject. The correlation coefficients between the mean PT of the phases of the three velocities gaits and PT defined by previous publications were all greater than 0.99. The correlation coefficient between velocity and PT of gait phases is -0.83 for loading response (LR), -0.75 for mid stance (MSt), and -0.84 for pre-swing (PSw). While the PT of the phases of three velocities from this study are highly correlated with PT described by Dr. Jacquenlin Perry decades ago, actual PT of each phase varied amongst these individuals with the largest coefficient variation of 24.31% for IC with slower velocity. From slower to faster walk, the mean PT of MSt diminished from 35.30% to 25.33%. High resolution recording revealed ambiguity of some gait phase definitions, and these data may benefit GC characterization of normal and pathological gait in clinical practice. The study results indicate that one should consider individual variations and walking velocity when evaluating gaits of subjects using standard gait phase classification.

  19. Thermochromic VO2 thin films deposited by magnetron sputtering for smart window applications

    Science.gov (United States)

    Fortier, Jean-Philippe

    "Smart" windows are a perfect innovative example of technology that reduces our energy dependence and our impact on the environment while saving on the economical point of view. With the use of vanadium dioxide (VO2), a thermochromic compound, and this, as a thin coating, it would in fact be possible to control the sun's transmission of infrared light (heat) as a function of the surrounding environment temperature. In other words, its optical behavior would allow a more effective management of heat exchanges between a living venue and the outdoor environment. However, this type of window is still in a developmental stage. First, the oxide's deposition is not simple in nature. Based on a conventional deposition technique called magnetron sputtering mainly used in the fenestration industry, several factors such as the oxygen concentration and the substrate temperature during deposition can affect the coating's thermochromic behavior, and this, by changing its composition and crystallinity. Other control parameters such as the deposition rate, the pressure in the sputtering chamber and the choice of substrate may also modify the film microstructure, thereby varying its optical and electrical properties. In addition, several issues still persist as to its commercial application. For starters, the material's structural transition, related to the change of its optical properties, only occurs around 68°C. In addition, its low transparency and natural greenish colour are not visually appealing. Then, to this day, the deposition temperature required to crystallize and form the thermochromic oxide remains an obstacle for a possible large-scale application. Ultimately, although the material's change in temperature has been shown to be advantageous in situations of varying climate, the existing corrective solutions to these issues generate a deterioration of the thermochromic behavior. With no practical expertise on the material, this project was undertaken with certain

  20. Sedimentary record of storm deposits from Hurricane Ike, Galveston and San Luis Islands, Texas

    Science.gov (United States)

    Hawkes, A. D.; Horton, B. P.

    2012-10-01

    Prehistoric records of land-falling tropical cyclones further our understanding of the spatial and temporal variability of tropical cyclone activity and its relationship with global climatic changes. Here, we describe deposit stratigraphy and sedimentology resulting from overwash during Hurricane Ike, which made landfall on September 13th 2008, to provide a much needed modern analogue for paleo-hurricane deposits and evaluate the hurricane's influence on barrier stability. We compared the volume, grain size distribution, organic content and foraminiferal assemblages of washover deposits at three sites from Galveston and San Luis Islands, Texas that were up to 50 km west of Ike's landfall. Storm surge heights varied between 3.7 and 2.7 m with inland inundation extents of 330 to 113 m. At each of the study sites, Hurricane Ike eroded the shoreline and re-deposited a landward-thinning sand sheet between 0.02 and 0.28 m thick over short-grass prairie/salt-marsh soil. Shoreline erosion estimates suggest that only between 10 and 30% of eroded beach sediment is deposited on land as washover (net gain to barrier elevation), while the remainder is re-deposited subtidally or offshore, a potential net loss to the coastal sediment budget. The washover sediment was readily identifiable by abrupt changes in grain size, organic content, and buried in situ grasses. Foraminiferal assemblages within washover and short-grass prairie/salt-marsh sediments (when present) have similar assemblages, which are dominated by Ammonia spp. and Elphidium spp. These species are common to bay and nearshore environments of the Gulf of Mexico. Foraminiferal species Bolivina subaenariensis, Quinqueloculina seminulum and planktonic species are restricted to the washover deposits, which may suggest sediment provenance from inner shelf environments.

  1. A Radon Progeny Deposition Model

    CERN Document Server

    Guiseppe, V E; Hime, A; Rielage, K; Westerdale, S

    2011-01-01

    The next generation low-background detectors operating underground aim for unprecedented low levels of radioactive backgrounds. Although the radioactive decays of airborne radon (particularly Rn-222) and its subsequent progeny present in an experiment are potential backgrounds, also problematic is the deposition of radon progeny on detector materials. Exposure to radon at any stage of assembly of an experiment can result in surface contamination by progeny supported by the long half life (22 y) of Pb-210 on sensitive locations of a detector. An understanding of the potential surface contamination from deposition will enable requirements of radon-reduced air and clean room environments for the assembly of low background experiments. It is known that there are a number of environmental factors that govern the deposition of progeny onto surfaces. However, existing models have not explored the impact of some environmental factors important for low background experiments. A test stand has been constructed to depos...

  2. Assessment of Lead and Beryllium deposition and adsorption to exposed stream channel sediments

    Science.gov (United States)

    Pawlowski, E.; Karwan, D. L.

    2016-12-01

    The fallout radionuclides Beryllium-7 and Lead-210 have been shown to be effective sediment tracers that readily bind to particles. The adsorption capacity has primarily been assessed in marine and coastal environments with an important assumption being the radionuclides' uniform spatial distribution as fallout from the atmosphere. This neglects localized storm events that may mine stratospheric reserves creating variable distributions. To test this assumption atmospheric deposition is collected at the University of Minnesota St. Paul Campus weather station during individual storm events and subsequently analyzed for Beryllium-7 and Lead-210. This provides further insight into continental effects on radionuclide deposition. The study of Beryllium-7 and Lead-210 adsorption in marine and coastal environments has provided valuable insights into the processes that influence the element's binding to particles but research has been limited in freshwater river environments. These environments have greater variation in pH, iron oxide content, and dissolved organic carbon (DOC) levels which have been shown to influence the adsorption of Beryllium and Lead in marine settings. This research assesses the adsorption of Beryllium and Lead to river sediments collected from in-channel deposits by utilizing batch experiments that mimic the stream conditions from which the deposits were collected. Soils were collected from Difficult Run, VA, and the West Swan River, MN. Agitating the soils in a controlled solution of known background electrolyte and pH while varying the level of iron oxides and DOC in step provides a better understanding of the sorption of Lead and Beryllium under the conditions found within freshwater streams. Pairing the partitioning of Lead and Beryllium with their inputs to streams via depositional processes, from this study and others, allows for their assessment as possible sediment tracers and age-dating tools within the respective watersheds.

  3. Chapter D: With or Without Salt-a Comparison of Marine and Continental-Lacustrine Diatomite Deposits

    Science.gov (United States)

    Moyle, Phillip R.; Dolley, Thomas P.

    2003-01-01

    Diatoms in sedimentary deposits of marine and continental, especially lacustrine, origin have similar nutrient (for example, phosphate, nitrate, and silica) and light requirements; however, their geologic ranges and physiographic environments vary. Marine diatoms range in age from Early Cretaceous to Holocene, and continental diatoms range in age from Eocene to Holocene; however, most commercial diatomites, both marine and lacustrine, were deposited during the Miocene. Marine deposits of commercial value generally accumulated along continental margins with submerged coastal basins and shelves where wind-driven boundary currents provided the nutrient-rich upwelling conditions capable of supporting a productive diatom habitat. Commercial freshwater diatomite deposits occur in volcanic terrains associated with events that formed sediment-starved drainage basins, such as the Basin and Range Province, particularly in Nevada. Marine habitats generally are characterized by stable conditions of temperature, salinity, pH, nutrients, and water currents, in contrast to lacustrine habitats, which are characterized by wide variations in these conditions. Marine deposits generally are of higher quality and contain larger resources, owing to their greater areal extent and thickness, whereas most of the world's known diatomites are of lacustrine origin. Both types of deposit are commonly mined by open-pit methods and subjected to processing designed to remove organic matter, CO2, pore water, and inorganic contaminants in order to produce purified products. The highest quality diatomites, predominantly from marine sources, are used in filtration, although both types of deposit produce filter grades, and additional end uses include fillers, additives, absorbents, and abrasives.

  4. Contribution of offshore petroleum deposits to marine food chain

    Science.gov (United States)

    Mori, S.

    2009-12-01

    Petroleum production out of offshore petroleum deposits often coincides with abundant fisheries in the world. Superposition of marine microorganism concentration distribution and offshore petroleum field distribution from various data in the literature provides to prove this coincidence. Sakhalin Island coastal regions, North Sea, Gulf of Mexico, etc. are chosen for the superpositions. Significant conformity is observed between the plankton concentration distribution and the offshore petroleum deposit distribution in all those regions. Also, most studies on the consequence of oil spills to marine eco-systems have focused mainly on hazardous marine pollution caused by spilled petroleum at high concentration in marine environment. However, some of those data clearly indicate stimulation of plankton population in properly low concentration levels of dissolved hydrocarbons and dissolved petroleum compositions. Further, increase of hydrocarbon concentration leads to its inhibition from its stimulation conditions upon crossing over a critical concentration level—a plankton stimulation/inhibition threshold concentration (SITC) of hydrocarbons. The SITC varies depending on hydrocarbon compounds, petroleum compositions, and microorganisms such as planktons. Further, petroleum composition diffusing through subterranean layers from petroleum deposits reacts with dissolved oxygen to be consumed at the ocean floor to precipitate the agglomerate suspension of hydrocarbons, leaving the sea water in a condition of oxygen depletion on the ocean floor. Such incidents are also briefly discussed.Plankton stimulation/inhibition threshold concentration of petroleum fractions

  5. Early Cambrian wave-formed shoreline deposits

    DEFF Research Database (Denmark)

    Clemmensen, Lars B; Glad, Aslaug Clemmensen; Pedersen, Gunver Krarup

    2017-01-01

    -preserved subaqueous dunes and wave ripples indicates deposition in a wave-dominated upper shoreface (littoral zone) environment, and the presence of interference ripples indicates that the littoral zone environment experienced water level fluctuations due to tides and/or changing meteorological conditions. Discoidal...

  6. Electro-spark deposition technology

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, R.N. [Pacific Northwest National Lab., Richland, WA (United States)

    1997-12-01

    Electro-Spark Deposition (ESD) is a micro-welding process that uses short duration, high-current electrical pulses to deposit or alloy a consumable electrode material onto a metallic substrate. The ESD process was developed to produce coatings for use in severe environments where most other coatings fail. Because of the exceptional damage resistance of these coatings, and the versatility of the process to apply a wide variety of alloys, intermetallics, and cermets to metal surfaces, the ESD process has been designated critical to the life and economy of the advanced fossil energy systems as the higher temperatures and corrosive environments exceed the limits of known structural materials to accommodate the service conditions. Developments include producing iron aluminide-based coatings with triple the corrosion resistance of the best previous Fe{sub 3}Al coatings, coatings with refractory metal diffusion barriers and multi layer coatings for achieving functionally gradient properties between the substrate and the surface. A new development is the demonstration of advanced aluminide-based ESD coatings for erosion and wear applications. One of the most significant breakthroughs to occur in the last dozen years is the discovery of a process regime that yields an order of magnitude increase in deposition rates and achievable coating thicknesses. Achieving this regime has required the development of advanced ESD electronic capabilities. Development is now focused on further improvements in deposition rates, system reliability when operating at process extremes, and economic competitiveness.

  7. Carbonatites of the World, Explored Deposits of Nb and REE - Database and Grade and Tonnage Models

    Science.gov (United States)

    Berger, Vladimir I.; Singer, Donald A.; Orris, Greta J.

    2009-01-01

    This report is based on published tonnage and grade data on 58 Nb- and rare-earth-element (REE)-bearing carbonatite deposits that are mostly well explored and are partially mined or contain resources of these elements. The deposits represent only a part of the known 527 carbonatites around the world, but they are characterized by reliable quantitative data on ore tonnages and grades of niobium and REE. Grade and tonnage models are an important component of mineral resource assessments. Carbonatites present one of the main natural sources of niobium and rare-earth elements, the economic importance of which grows consistently. A purpose of this report is to update earlier publications. New information about known deposits, as well as data on new deposits published during the last decade, are incorporated in the present paper. The compiled database (appendix 1; linked to right) contains 60 explored Nb- and REE-bearing carbonatite deposits - resources of 55 of these deposits are taken from publications. In the present updated grade-tonnage model we have added 24 deposits comparing with the previous model of Singer (1998). Resources of most deposits are residuum ores in the upper part of carbonatite bodies. Mineral-deposit models are important in exploration planning and quantitative resource assessments for two reasons: (1) grades and tonnages among deposit types vary significantly, and (2) deposits of different types are present in distinct geologic settings that can be identified from geologic maps. Mineral-deposit models combine the diverse geoscience information on geology, mineral occurrences, geophysics, and geochemistry used in resource assessments and mineral exploration. Globally based deposit models allow recognition of important features and demonstrate how common different features are. Well-designed deposit models allow geologists to deduce possible mineral-deposit types in a given geologic environment, and the grade and tonnage models allow economists to

  8. A lithium deposition system for tokamak devices*

    Science.gov (United States)

    Graziul, Christopher; Majeski, Richard; Kaita, Robert; Hoffman, Daniel; Timberlake, John; Card, David

    2002-11-01

    The production of a lithium deposition system using commercially available components is discussed. This system is intended to provide a fresh lithium wall coating between discharges in a tokamak. For this purpose, a film 100-200 Å thick is sufficient to ensure that the plasma interacts solely with the lithium. A test system consisting of a lithium evaporator and a deposition monitor has been designed and constructed to investigate deposition rates and coverage. A Thermionics 3kW e-gun is used to rapidly evaporate small amounts of solid lithium. An Inficon XTM/2 quartz deposition monitor then measures deposition rate at varying distances, positions and angles relative to the e-gun crucible. Initial results from the test system will be presented. *Supported by US DOE contract #DE-AC02-76CH-03073

  9. Plasma sprayed and electrospark deposited zirconium metal diffusion barrier coatings

    Energy Technology Data Exchange (ETDEWEB)

    Hollis, Kendall J [Los Alamos National Laboratory; Pena, Maria I [Los Alamos National Laboratory

    2010-01-01

    Zirconium metal coatings applied by plasma spraying and electrospark deposition (ESD) have been investigated for use as diffusion barrier coatings on low enrichment uranium fuel for research nuclear reactors. The coatings have been applied to both stainless steel as a surrogate and to simulated nuclear fuel uranium-molybdenum alloy substrates. Deposition parameter development accompanied by coating characterization has been performed. The structure of the plasma sprayed coating was shown to vary with transferred arc current during deposition. The structure of ESD coatings was shown to vary with the capacitance of the deposition equipment.

  10. Effects of thermal environment and supplementation levels on the physiological parameters of moxotó goats in confined and semi-confined rising systems Efeito do ambiente térmico e suplementação nas variáveis fisiológicas de caprinos moxotó em confinamento e semiconfinamento

    Directory of Open Access Journals (Sweden)

    Dermeval A. Furtado

    2008-09-01

    Full Text Available The objective of this work was to determine the effect of environmental variables and supplementation levels on physiological parameters of Moxotó goats in confined and semi-confined rising systems, in the Brazilian semi-arid region. The semi-confined individuals were kept on a grass based diet during the day and arrested in the end of the afternoon. The confined animals were kept in a management center, receiving two diets composed by forage cactus and maniçoba hay into two different levels (0.5 and 1.5% of the body weight. Inside the management center and in the external environment the environmental comfort parameters were set high during the afternoon period characterizing a situation of thermal discomfort for the animals. During the morning the semi-confined animals presented an average respiratory frequency (69.5 mov min-1 and rectal temperature (39.5 ºC higher than the confined ones (62.6 mov min-1 and 39.0 ºC, respectively. The confined and semi-confined animals were able to maintain their rectal temperature within normal limits, with increase in the cardiac beatings rate and respiratory frequency. The greater percentage of the used supplementations (1.5% seemed to increase rectal temperature in the two studied rising systems.Este trabalho teve os objetivos de determinar e de avaliar o efeito das variáveis ambientais e quantidade de suplementação, com concentrados, nas variáveis fisiológicas de caprinos Moxotó, confinados e semiconfinados, no semi-árido nordestino. Os animais semiconfinados foram mantidos em regime de pasto durante o dia e recolhidos ao final da tarde. Os animais confinados foram mantidos em um centro de manejo, recebendo duas dietas compostas por palma forrageira e feno de maniçoba, com duas quantidades de concentrados (0,5 e 1,5% do peso vivo. No interior do aprisco e no ambiente externo, os índices de conforto ambiental ficaram elevados no período da tarde, caracterizando situação de desconforto t

  11. Measurement of the deposition of aerosol particles to skin, hair and clothing

    CERN Document Server

    Bell, K F

    1998-01-01

    efficient. range 1.3 -15x10 sup - sup 3 ms sup - sup 1 were recorded, values which are approximately an order of magnitude higher than the equivalent values onto the floor of the test room. These values suggest that the exposure route of radioactive aerosol particles deposited on the skin may be more significant than hitherto had been assumed. The possible mechanisms leading to this relatively high deposition were investigated experimentally and the results suggested that a combination of factors such as the body's electrostatic field, surface temperature and surface roughness were contributors. A wind tunnel was used to carry out experiments to compare the deposition velocities of a 1.4 mu m mean diameter aerosol onto human body phantoms in a simulated outdoor environment with the values from the test chamber experiments. The measured aerosol deposition velocities were found to vary with wind velocity; values in the range 6.8 - 11x10 sup - sup 3 ms sup - sup 1 were recorded. The clearance of deposited aeroso...

  12. Plasma polymers deposited in atmospheric pressure dielectric barrier discharges: Influence of process parameters on film properties

    Energy Technology Data Exchange (ETDEWEB)

    Fricke, Katja, E-mail: k.fricke@inp-greifswald.de [Leibniz Institute for Plasma Science and Technology e.V. (INP Greifswald), Felix-Hausdorff-Str. 2, 17489 Greifswald (Germany); Girard-Lauriault, Pierre-Luc [Plasma Processing Laboratory, Department of Chemical Engineering, McGill University, 3610 rue University, Montreal, QC H3A 0C5 (Canada); Weltmann, Klaus-Dieter [Leibniz Institute for Plasma Science and Technology e.V. (INP Greifswald), Felix-Hausdorff-Str. 2, 17489 Greifswald (Germany); Wertheimer, Michael R. [Department of Engineering Physics, École Polytechnique de Montréal, Box 6079, Station Centre-Ville, Montreal, QC H3C 3A7 (Canada)

    2016-03-31

    We present results on the deposition of plasma polymer (PP) films in a dielectric barrier discharge system fed with mixtures of argon or nitrogen carrier gas plus different hydrocarbon precursors, where the latter possess different carbon-to-hydrogen ratios: CH{sub 4} < C{sub 2}H{sub 6} < C{sub 2}H{sub 4} = C{sub 3}H{sub 6} < C{sub 2}H{sub 2}. The influence of precursor gas mixture and flow rate, excitation frequency, and absorbed power on PP film compositions and properties has been investigated. The discharge was characterized by electrical measurements, while the chemical compositions and structures of coatings were analysed by X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, total combustion, and elastic recoil detection analyses, the latter two for determining carbon-to-hydrogen ratios. Scanning electron microscopy was used to study the coatings' morphology, and profilometry for evaluating deposition rates. - Highlights: • Atmospheric pressure DBD is used to deposit organic hydrocarbon films. • High deposition rates can be achieved by varying the power and/or gas mixture ratio. • Process parameters affect the films' surface chemical composition and morphology. • Deposited films are not soluble in aqueous environment. • No delamination of coatings produced from argon plasma.

  13. Solubility of deposited airborne heavy metals

    Science.gov (United States)

    Cizmecioglu, Sibel C.; Muezzinoglu, Aysen

    2008-09-01

    Toxic effects of heavy metals in water and soil environments are important. Quantifying the heavy metal concentrations and their solubilities in dry and wet deposition samples is part of atmospheric research. Soluble fractions of the deposited air pollutants are important in food chain mechanisms as heavy metals may cause ecotoxic impacts. In this study, the solubilities of Cr, Cd, Pb, Cu, Zn, and Ni were investigated in deposition samples for total, dissolved, and suspended fractions after collection in a surrogate, water-surface sampler in Izmir, Turkey, during October 2003 to June 2004. To find overall solubility of each metal in dry and wet deposition samples, concentrations in soluble and suspended phases of aqueous solutions were analyzed separately. Ratios between total and dissolved forms and the metals in the same forms were analyzed and evaluated statistically. It was found that the deposited metal fluxes were significantly correlated in wet deposition with the highest correlation between Cd and Pb in the soluble and total forms. Comparatively smaller correlations were found between these metal fluxes in dry deposition samples. Results of this study showed the importance of metal pollution, especially ecotoxic properties of heavy metals in wet deposition far more than dry deposition.

  14. Rock-forming and Ore-forming Ages as well as Formation Environments of Porphyry Molybdenum Deposits in Beishan Area, Inner Mongolia%内蒙古北山地区斑岩型钼矿的成岩成矿时代和形成环境探讨

    Institute of Scientific and Technical Information of China (English)

    杨岳清; 赵金花; 孟贵祥; 严加永; 吕博; 王守光; 贾玲珑; 韩建刚

    2013-01-01

    A nearly EW-trending molybdenum (copper) ore belt was found in Beishan area of Inner Mongolia. The relatively large deposits in this belt include Liushashan molybdenum deposit, Elegenwulanwula molybdenum deposit and Xiaohulishan molybdenum deposit., Re-Os isotope dating of molybdenite samples from these three deposits yielded isochron ages of (260±10) Ma (Middle Permian), 332.0 Ma (Early Carboniferous) and 220 Ma (Late Triassic) respectively. Obviously, different metallogenic epochs reflect different environments for the formation of these deposits. Based on new SHRIMP zircon U-Pb age data of the porphyry related to mineralization as well as basic rock and ore geochemical work, the authors revealed the formation environments of the three deposits from the angle of regional crustal evolution. In the Early Paleozoic, the three deposits were in Kazakhstan plate, and in the Late Paleozoic, due to the development of Hongshishan-Baiheshan-Pengboshan area from rift valley to ocean basin, the position of the Liushashan molybdenum deposit was split into the Tarim plate. Due to the difference in subduction mechanism and underlying basement, tectono-magmatic activities were somewhat different in two island arcs. In active marginal belt of north Tarim plate, magmatic activity was unusually strong and lasted from Carboniferous to the end of Permian. In the early stage, mineralization was dominated mainly by iron, and molybdenum (copper) deposits were formed in the late stage. Magmatic activity of the marginal belt in south Kazakhstan plate was a bit weaker than that in the northern marginal belt of Tarim plate, and the magmatic activity was mainly concentrated in Carboniferous; in such an environment, the Elegenwulanwula molybdenum deposit was formed. At the end of Permian, the split plate of Beishan area became a unified plate again through collage. From that time on, Beishan area entered into an environment of intra-continental crustal activity, and stretching

  15. High Energy Radial Deposition of Diamond-Like Carbon Coatings

    Directory of Open Access Journals (Sweden)

    Konrad Suschke

    2015-07-01

    Full Text Available Diamond-like carbon (DLC coatings were deposited with a new direct ion deposition system using a novel 360 degree ion source operating at acceleration voltage between 4 and 8 kV. Cross-sectional TEM images show that the coatings have a three layered structure which originates from changes in the deposition parameters taking into account ion source condition, ion current density, deposition angles, ion sputtering and ion source movement. Varying structural growth conditions can be achieved by tailoring the deposition parameters. The coatings show good promise for industrial use due to their high hardness, low friction and excellent adhesion to the surface of the samples.

  16. TULSA UNIVERSITY PARAFFIN DEPOSITION PROJECTS

    Energy Technology Data Exchange (ETDEWEB)

    Cem Sarica; Michael Volk

    2004-06-01

    As oil and gas production moves to deeper and colder water, subsea multiphase production systems become critical for economic feasibility. It will also become increasingly imperative to adequately identify the conditions for paraffin precipitation and predict paraffin deposition rates to optimize the design and operation of these multi-phase production systems. Although several oil companies have paraffin deposition predictive capabilities for single-phase oil flow, these predictive capabilities are not suitable for the multiphase flow conditions encountered in most flowlines and wellbores. For deepwater applications in the Gulf of Mexico, it is likely that multiphase production streams consisting of crude oil, produced water and gas will be transported in a single multiphase pipeline to minimize capital cost and complexity at the mudline. Existing single-phase (crude oil) paraffin deposition predictive tools are clearly inadequate to accurately design these pipelines, because they do not account for the second and third phases, namely, produced water and gas. The objective of this program is to utilize the current test facilities at The University of Tulsa, as well as member company expertise, to accomplish the following: enhance our understanding of paraffin deposition in single and two-phase (gas-oil) flows; conduct focused experiments to better understand various aspects of deposition physics; and, utilize knowledge gained from experimental modeling studies to enhance the computer programs developed in the previous JIP for predicting paraffin deposition in single and two-phase flow environments. These refined computer models will then be tested against field data from member company pipelines.

  17. Radon diffusion coefficients in soils of varying moisture content

    Science.gov (United States)

    Papachristodoulou, C.; Ioannides, K.; Pavlides, S.

    2009-04-01

    Radon is a naturally occurring radioactive gas that is generated in the Earth's crust and is free to migrate through soil and be released to the atmosphere. Due to its unique properties, soil gas radon has been established as a powerful tracer used for a variety of purposes, such as exploring uranium ores, locating geothermal resources and hydrocarbon deposits, mapping geological faults, predicting seismic activity or volcanic eruptions and testing atmospheric transport models. Much attention has also been given to the radiological health hazard posed by increased radon concentrations in the living and working environment. In order to exploit radon profiles for geophysical purposes and also to predict its entry indoors, it is necessary to study its transport through soils. Among other factors, the importance of soil moisture in such studies has been largely highlighted and it is widely accepted that any measurement of radon transport parameters should be accompanied by a measurement of the soil moisture content. In principle, validation of transport models in the field is encountered by a large number of uncontrollable and varying parameters; laboratory methods are therefore preferred, allowing for experiments to be conducted under well-specified and uniform conditions. In this work, a laboratory technique has been applied for studying the effect of soil moisture content on radon diffusion. A vertical diffusion chamber was employed, in which radon was produced from a 226Ra source, was allowed to diffuse through a soil column and was finally monitored using a silicon surface barrier detector. By solving the steady-state radon diffusion equation, diffusion coefficients (D) were determined for soil samples of varying moisture content (m), from null (m=0) to saturation (m=1). For dry soil, a D value of 4.1×10-7 m2s-1 was determined, which increased moderately by a factor of ~3 for soil with low moisture content, i.e. up to m ~0.2. At higher water fractions, a decrease

  18. Cascadia Tsunami Deposit Database

    Science.gov (United States)

    Peters, Robert; Jaffe, Bruce; Gelfenbaum, Guy; Peterson, Curt

    2003-01-01

    The Cascadia Tsunami Deposit Database contains data on the location and sedimentological properties of tsunami deposits found along the Cascadia margin. Data have been compiled from 52 studies, documenting 59 sites from northern California to Vancouver Island, British Columbia that contain known or potential tsunami deposits. Bibliographical references are provided for all sites included in the database. Cascadia tsunami deposits are usually seen as anomalous sand layers in coastal marsh or lake sediments. The studies cited in the database use numerous criteria based on sedimentary characteristics to distinguish tsunami deposits from sand layers deposited by other processes, such as river flooding and storm surges. Several studies cited in the database contain evidence for more than one tsunami at a site. Data categories include age, thickness, layering, grainsize, and other sedimentological characteristics of Cascadia tsunami deposits. The database documents the variability observed in tsunami deposits found along the Cascadia margin.

  19. 甘肃龙尾沟斑岩型铜(钨)矿床成矿特征及形成环境%Geological Characteristics and Metallogenic Environment of the Longweigou Porphyry Copper(tungsten) Deposit,Gansu

    Institute of Scientific and Technical Information of China (English)

    贾群子; 马云海; 全守村; 王建军; 肖朝阳; 李金超

    2012-01-01

    龙尾沟铜(钨)矿床是祁连山地区新近发现的一处斑岩型矿床,其评价及研究对祁连山地区铜矿勘查具有重要的指导和借鉴作用.本文通过对含矿斑岩年代学及地球化学、矿体产出特征及矿石物质组成、围岩蚀变等进行了系统研究,结果表明,花岗闪长斑岩形成年龄为358.7 Ma;矿体呈似层状、透镜状和脉状产出,主要产于高钾碱性系列斑岩体内,并受近南北向构造控制;矿石矿物主要为黄铜矿、黄铁矿、磁黄铁矿、白钨矿,呈细脉一浸染状、浸染状产出;矿化以富铜、钨、金贫钼为特征;与成矿关系密切的围岩蚀变主要为绢英岩化,次为钾硅酸盐化和硅化;矿床成矿时代为海西早期,形成于陆内造山伸展环境.从成矿背景分析认为祁连山地区陆内造山环境所形成的斑岩型铜矿具有良好的找矿前景.%The Longweigou porphyry copper( tungsten) deposit, a newly found deposit, lies in the Oulongbuluke uplift belt of the Qilian orogenic belt. The evaluation and research of the Longweigou copperCtungsten) ore deposit will present important guidance and reference for copper exploration in the Qilian Mountain area. The chronology and the geochemistry of the ore-bearing porphyry deposit were studied and the occurrence features of the deposit, the components of gold mineral and the alteration of the wall rock were investigated. Results showed that the formation age of the granodiorite porphyry is 358. 7Ma; and that the ore-body, which has occurrences of stratiform or lenticular or vein, occurs mainly in the high potassium alkali series porphyry and is controlled by NS structures; and that chalcopyrite, pyrite, pyrrhotite, and scheelite are main ore minerals, which have veinlet-disseminated and disseminated structures; and that mineralization is characterized by enriching copper, tungsten and gold and depleting molybdenum; and that the mineralization related wall-rock alterations are

  20. Deposition of Aerosols in the Lung: Physiological Factors

    Science.gov (United States)

    Ventilation and mechanics of breathing are an integral part of respiratory physiology that directly affect aerosol transport and deposition in the lung. Although natural breathing pattern varies widely among individuals, breathing pattern is controllable, and by using an appropri...

  1. Proximal pyroclastic deposits from the 1989-1990 eruption of Redoubt Volcano, Alaska - stratigraphy, distribution, and physical characteristics

    Science.gov (United States)

    Gardner, C.A.; Neal, C.A.; Waitt, R.B.; Janda, R.J.

    1994-01-01

    More than 20 eruptive events during the 1989-1990 eruption of Redoubt Volcano emplaced a complex sequence of lithic pyroclastic-flow, -surge, -fall, ice-diamict, and lahar deposits mainly on the north side of the volcano. The deposits record the changing eruption dynamics from initial gas-rich vent-clearing explosions to episodic gas-poor lava-dome extrusions and failures. The repeated dome failures produced lithic pyroclastic flows that mixed with snow and glacial ice to generate lahars that were channelled off Drift glacier into the Drift River valley. Some of the dome failures occurred without precursory seismic warning and appeared to result solely from gravitational instability. Material from the disrupted lava domes avalanched down a steep, partly ice-filled canyon incised on the north flank of the volcano and came to rest on the heavily crevassed surface of the piedmont lobe of Drift glacier. Most dome-collapse events resulted in single, monolithologic, massive to reversely graded, medium- to coarse-grained, sandy pyroclastic-flow deposits containing abundant dense dome clasts. These deposits vary in thickness, grain size, and texture depending on distance from the vent and local topography; deposits are finer and better sorted down flow, thinner and finer on hummocks, and thicker and coarser where ponded in channels cut through the glacial ice. The initial vent-clearing explosions emplaced unusual deposits of glacial ice, snow, and rock in a frozen matrix on the north and south flanks of the volcano. Similar deposits were described at Nevado del Ruiz, Columbia and have probably been emplaced at other snow-and-ice-clad volcanoes, but poor preservation makes them difficult to recognize in the geologic record. In a like fashion, most deposits from the 1989-1990 eruption of Redoubt Volcano may be difficult to recognize and interpret in the future because they were emplaced in an environment where glacio-fluvial processes dominate and quickly obscure the primary

  2. Sulfur- and oxygen-isotopes in sediment-hosted stratiform barite deposits

    Science.gov (United States)

    Johnson, C.A.; Emsbo, P.; Poole, F.G.; Rye, R.O.

    2009-01-01

    Sulfur- and oxygen-isotope analyses have been obtained for sediment-hosted stratiform barite deposits in Alaska, Nevada, Mexico, and China to examine the environment of formation of this deposit type. The barite is contained in sedimentary sequences as old as Late Neoproterozoic and as young as Mississippian. If previously published data for other localities are considered, sulfur- and oxygen-isotope data are now available for deposits spanning a host-rock age range of Late Neoproterozoic to Triassic. On a ??34S versus ??18O diagram, many deposits show linear or concave-upward trends that project down toward the isotopic composition of seawater sulfate. The trends suggest that barite formed from seawater sulfate that had been isotopically modified to varying degrees. The ??34S versus ??18O patterns resemble patterns that have been observed in the modern oceans in pore water sulfate and water column sulfate in some anoxic basins. However, the closest isotopic analog is barite mineralization that occurs at fluid seeps on modern continental margins. Thus the data favor genetic models for the deposits in which barium was delivered by seafloor seeps over models in which barium was delivered by sedimentation of pelagic organisms. The isotopic variations within the deposits appear to reflect bacterial sulfate reduction operating at different rates and possibly with different electron donors, oxygen isotope exchange between reduction intermediates and H2O, and sulfate availability. Because they are isotopically heterogeneous, sediment-hosted stratiform barite deposits are of limited value in reconstructing the isotopic composition of ancient seawater sulfate.

  3. {sup 137}Cs in French soils: Deposition patterns and 15-year evolution

    Energy Technology Data Exchange (ETDEWEB)

    Roussel-Debel, Sylvie [Institute for Radioprotection and Nuclear Safety (France)]. E-mail: sylvie.roussel-debet@irsn.fr; Renaud, Philippe [Institute for Radioprotection and Nuclear Safety (France); Metivier, Jean-Michel [Institute for Radioprotection and Nuclear Safety (France)

    2007-03-15

    Around 2000 surface samples have been taken from French soil at around twenty stations over the last fifteen years. Caesium 137, the only artificial radionuclide in the terrestrial environment currently detectable with gamma spectroscopy, was measured in the samples. The levels of caesium activity were compared to deposition estimates for deposits from atmospheric weapons tests and Chernobyl fallout. Since the start of data acquisition, specific activity in the samples has decreased with a mean effective half-life of between 8 and 11 y, for meadow soil and agricultural soil respectively. These field observations confirm that the conventional soil migration-retention model, which uses distribution coefficient Kd, is insufficient for modelling caesium distribution in the surface soil layer. Although the differences between sites tend to diminish with time, surface specific activity in agricultural and meadow soil varies on average from a few Bq to several tens of Bq per kg of dry matter.

  4. {sup 137}Cs in French soils. Deposition patterns and 15-year evolution

    Energy Technology Data Exchange (ETDEWEB)

    Roussel-Debel, Sylvie; Renaud, Philippe; Metivier, Jean-Michel [Institute for Radioprotection and Nuclear Safety, Clamart (France)

    2007-03-15

    Around 2000 surface samples have been taken from French soil at around twenty stations over the last fifteen years. Caesium 137, the only artificial radionuclide in the terrestrial environment currently detectable with gamma spectroscopy, was measured in the samples. The levels of caesium activity were compared to deposition estimates for deposits from atmospheric weapons tests and Chernobyl fallout. Since the start of data acquisition, specific activity in the samples has decreased with a mean effective half-life of between 8 and 11 y, for meadow soil and agricultural soil respectively. These field observations confirm that the conventional soil migration-retention model, which uses distribution coefficient Kd, is insufficient for modelling caesium distribution in the surface soil layer. Although the differences between sites tend to diminish with time, surface specific activity in agricultural and meadow soil varies on average from a few Bq to several tens of Bq per kg of dry matter. (author)

  5. Compilation of Mineral Resource Data for Mississippi Valley-Type and Clastic-Dominated Sediment-Hosted Lead-Zinc Deposits

    Science.gov (United States)

    Taylor, Ryan D.; Leach, David L.; Bradley, Dwight C.; Pisarevsky, Sergei A.

    2009-01-01

    This report contains a global compilation of the mineral resource data for sediment-hosted lead-zinc (SH Pb-Zn) deposits. Sediment-hosted lead-zinc deposits are historically the most significant sources of lead and zinc, and are mined throughout the world. The most important SH Pb-Zn deposits are hosted in clastic-dominated sedimentary rock sequences (CD Pb-Zn) that are traditionally called sedimentary exhalative (SEDEX) deposits, and those in carbonate-dominated sequences that are known as Mississippi Valley-type (MVT) Pb-Zn deposits. In this report, we do not include sandstone-Pb, sandstone-hosted Pb, or Pb-Zn vein districts such as those in Freiberg, Germany, or Coeur d'Alene, Idaho, because these deposits probably represent different deposit types (Leach and others, 2005). We do not include fracture-controlled deposits in which fluorite is dominant and barite typically abundant (for example, Central Kentucky; Hansonburg, N. Mex.) or the stratabound fluorite-rich, but also lead- and zinc-bearing deposits, such as those in southern Illinois, which are considered a genetic variant of carbonate-hosted Pb-Zn deposits (Leach and Sangster, 1993). This report updates the Pb, Zn, copper (Cu), and silver (Ag) grade and tonnage data in Leach and others (2005), which itself was based on efforts in the Canadian Geological Survey World Minerals Geoscience Database Project (contributions of D.F. Sangster to Sinclair and others, 1999). New geological or geochronological data, classifications of the tectonic environment in which the deposits formed, and key references to the geology of the deposits are presented in our report. Data for 121 CD deposits, 113 MVT deposits, and 6 unclassified deposits that were previously classified as either SEDEX or MVT in the Leach and others (2005) compilation, are given in appendix table A1. In some cases, mineral resource data were available only for total district resources, but not for individual mines within the district. For these

  6. GPU Generation of Large Varied Animated Crowds

    OpenAIRE

    Isaac Rudomin; Benjamín Hernández; Oriam de Gyves; Leonel Toledo; Ivan Rivalcoba; Sergio Ruiz

    2013-01-01

    ..We discuss several steps in the process of simulating and visualizing large and varied crowds in real time for consumer-level computers and graphic cards (GPUs). Animating varied crowds using a diversity of models and animations (assets) is complex and costly. One has to use models that are expensive if bought, take a long time to model, and consume too much memory and computing resources. We discuss methods for simulating, generating, animating and rendering crowds of varied aspect and a d...

  7. A new varied-time photonic crystals

    OpenAIRE

    Wu, Xiang-Yao; Ma, Ji; Liu, Xiao-Jing; Liang, Yu; Li, Hong; Chen, Wan-Jin; Yuan, Hong-chun; Li, Heng-Mei

    2015-01-01

    In this paper, we have firstly proposed a new one-dimensional varied-time photonic crystals, i.e., the refractive indices of media $A$ and $B$ are the time functions. We consider the varied-time photonic crystals of refractive indices period variation and calculate the transmissivity and electronic field distribution with and without defect layer, which are different from the conventional photonic crystals, which transmissivity and electronic field distribution are static, but the varied-time...

  8. Inflationary Phase with Time Varying Fundamental Constants

    CERN Document Server

    Berman, M S; Berman, Marcelo S.; Trevisan, Luis A.

    2002-01-01

    Following Barrow, and Barrow and collaborators, we find a cosmological JBD model, with varying speed of light and varying fine structure constant, where the deceleration parameter is -1,causing acceleration of the Universe.Indeed, we have an exponential inflationary phase. Plancks time, energy, length,etc.,might have had different numerical values in the past, than those available in the litterature, due to the varying values for speed of light, and gravitational constant.

  9. A new varied-time photonic crystals

    OpenAIRE

    2015-01-01

    In this paper, we have firstly proposed a new one-dimensional varied-time photonic crystals, i.e., the refractive indices of media $A$ and $B$ are the time functions. We consider the varied-time photonic crystals of refractive indices period variation and calculate the transmissivity and electronic field distribution with and without defect layer, which are different from the conventional photonic crystals, which transmissivity and electronic field distribution are static, but the varied-time...

  10. Deposition of copper coatings in a magnetron with liquid target

    Energy Technology Data Exchange (ETDEWEB)

    Tumarkin, A. V., E-mail: sanyahrustal@mail.ru; Kaziev, A. V.; Kolodko, D. V.; Pisarev, A. A.; Kharkov, M. M.; Khodachenko, G. V. [National Research Nuclear University MEPhI (Moscow Engineering Physics Institute) (Russian Federation)

    2015-12-15

    Copper coatings were deposited on monocrystalline Si substrates using a magnetron discharge with a liquid cathode in the metal vapour plasma. During the deposition, the bias voltage in the range from 0 V to–400 V was applied to the substrate. The prepared films were investigated by a scanning electron microscope, and their adhesive properties were studied using a scratch tester. It was demonstrated that the adhesion of the deposited films strongly depends on the bias voltage and varies in a wide range.

  11. Biomimetic thin film deposition

    Science.gov (United States)

    Rieke, P. C.; Campbell, A. A.; Tarasevich, B. J.; Fryxell, G. E.; Bentjen, S. B.

    1991-04-01

    Surfaces derivatized with organic functional groups were used to promote the deposition of thin films of inorganic minerals. These derivatized surfaces were designed to mimic the nucleation proteins that control mineral deposition during formation of bone, shell, and other hard tissues in living organisms. By the use of derivatized substrates control was obtained over the phase of mineral deposited, the orientation of the crystal lattice and the location of deposition. These features are of considerable importance in many technically important thin films, coatings, and composite materials. Methods of derivatizing surfaces are considered and examples of controlled mineral deposition are presented.

  12. Ion-assisted deposition of lanthanide trifluorides for VUV applications

    Science.gov (United States)

    Lingg, L. J.; Targove, J. D.; Lehan, J. P.; Macleod, H. A.

    1987-01-01

    The lanthanide trifluorides show promise as vacuum ultraviolet (VUV) coating materials. The optical properties of single-layer coatings vary with deposition temperature, and with ion-beam energy and current density. The optical constants, stoichiometry, durability, moisture adsorption, and crystallinity are studied for trifluoride films made under a variety of deposition conditions.

  13. The compositional and physical properties of localized lunar pyroclastic deposits

    Science.gov (United States)

    Trang, David; Gillis-Davis, Jeffrey J.; Lemelin, Myriam; Cahill, Joshua T. S.; Hawke, B. Ray; Giguere, Thomas A.

    2017-02-01

    Lunar localized pyroclastic deposits are low albedo deposits with areas thermal-infrared-derived measures of surficial rock abundance and regolith density, and mineral abundances. Our goals are to (1) quantitatively characterize the physical and mineralogical properties of each localized pyroclastic deposit, (2) investigate the physical and mineralogical variations among localized pyroclastic deposits, (3) compare these properties of localized ( 2500 km2), and (4) provide useful parameters for future volcanological modeling. From this study, we find that: (1) localized pyroclastic deposits exhibit low relief structures, (2) the surface rock abundance and circular polarization ratio of localized pyroclastic deposits display a wide range of values (0.2-0.5% and 0.3-0.6, respectively), (3) the glass abundance of localized pyroclastic deposits vary between ∼0 and ∼80 wt.%, (4) there are four types of localized pyroclastic deposits based upon the surface rock abundance and glass abundance parameters, (5) pyroclastic deposits within the same floor-fractured crater tend to have similar properties, and (6) localized pyroclastic deposits are diverse with respect to regional pyroclastic deposits, but a subset of localized pyroclastic deposits have similar physical and mineralogical properties to regional pyroclastic deposits.

  14. Paleobiological implications of dinosaur egg-bearing deposits in the Cretaceous Gyeongsang Supergroup of Korea

    Science.gov (United States)

    Paik, In Sung; Kim, Hyun Joo; Huh, Min

    2010-05-01

    of angiosperm trees in ecological range through swamps and floodplains during the Late Cretaceous and subsequent change of herbivorous dinosaurs' dietary habit and the increase of volcanic activity in the Cretaceous. The other is related with the nesting behaviour in the Cretaceous. By contrast to the geochronologically restricted occurrence of dinosaur eggs, paleoenvironments of nesting areas of dinosaurs are varying from inland areas (alluvial fan, fluvial plain, desert, lake, etc.) to coastal areas (coastal plain, beach, lagoon), suggesting that dinosaurs avoided competition in sharing nesting areas. Little change in lithology from nested deposits to subsequent burying sediments indicates that dinosaurs preferred stable environment in terms of sedimentation as nesting sites. Key words: Dinosaur eggs, Cretaceous, Paleobiological occurrence, Korea

  15. Structural and Optical Properties of Chemical Bath Deposited Silver Oxide Thin Films: Role of Deposition Time

    Directory of Open Access Journals (Sweden)

    A. C. Nwanya

    2013-01-01

    Full Text Available Silver oxide thin films were deposited on glass substrates at a temperature of 50°C by chemical bath deposition technique under different deposition times using pure AgNO3 precursor and triethanolamine as the complexing agent. The chemical analysis based on EDX technique shows the presence of Ag and O at the appropriate energy levels. The morphological features obtained from SEM showed that the AgxO structures varied as the deposition time changes. The X-ray diffraction showed the peaks of Ag2O and AgO in the structure. The direct band gap and the refractive index increased as the deposition time increased and was in the range of 1.64–1.95 eV and 1.02–2.07, respectively. The values of the band gap and refractive index obtained indicate possible applications in photovoltaic and photothermal systems.

  16. Assessment on the Environment Impact of Mining and Milling Process of an Uranium Deposit in North China%北方某铀矿采冶工程环境影响预测与评价

    Institute of Scientific and Technical Information of China (English)

    杨莹; 杜喜臣; 蔡敏琦

    2013-01-01

    针对我国北方某铀矿采冶工程,全面分析工程的主要放射性污染源,预测并评价放射性污染源对环境的可能影响,分析其非放射性环境影响,并给出主要评价结论;同时提出了辐射防护与环境保护措施,对铀矿资源开采及环境保护工作的开展具有指导意义.%The main radioacitive pollution sources were analyzed comprehensivly during the mining and milling process of an uranium deposit in North China, the possible radioactive environmental impact from these source was evaluated and predicted. The paper also analyzed the non-radioactive environmental impact from the mining and milling, and presented the main evaluation conclusion. Some useful measures of radioactive protection and environmental reservation were proposed for the efforts of uranium deposit mining.

  17. Lithology and palynology of Neogene sediments on the narrow edge of the Kitakami Massif (basement rocks), northeast Japan: significant change for depositional environments as a result of plate tectonics

    Energy Technology Data Exchange (ETDEWEB)

    Koji Yagishita; Akiko Obuse; Hiroshi Kurita [Iwate University, Morioka-City (Japan). Department of Geology, Faculty of Education

    2003-09-01

    A controversial stratigraphic section, the Taneichi Formation, is exposed along the Pacific Coast of northeastern Honshu, the main island of the Japanese Archipelago. Although most sediments of the formation have long been dated as late Cretaceous, the northern section of it has been assigned to (I) the Upper Cretaceous; (ii) the Paleogene; or (iii) the Neogene. In the present report, we present the data of palynological and sedimentological studies, showing that the northern section should be assigned to the Neogene. A more important point in the present study is that we invoke some basic principles of fluvial sedimentology to resolve this stratigraphic subject. The lignite layers full of PaleogeneMiocene dinoflagellate cysts and pollen assemblages drape over the boulder-sized ({gt}40 cm in diameter) clasts in the northern section. However, the layers totally consist of aggregates of small lignite chips, indicating that the lignites are allochthonous materials. The mega-clasts with derived microfossils in the lignites are thought to have been deposited as Neogene fluvial (flood) sediments in the newly formed Japanese Archipelago. Prior to the Miocene, the northern Honshu was part of the Eurasian Plate, thus the boulder-sized clasts cannot be envisaged as long river flood deposits along the continental Paleogene Pacific Coast. Instead, the mega-clasts with the draping lignites were probably derived from nearby Miocene highlands in the newly born island arc.

  18. Manganese deposition in drinking water distribution systems

    Energy Technology Data Exchange (ETDEWEB)

    Gerke, Tammie L., E-mail: Tammie.Gerke@miamioh.edu [Department of Geology, University of Cincinnati, Cincinnati, OH 45221-0013 (United States); Little, Brenda J., E-mail: brenda.little@nrlssc.navy.mil [Naval Research Laboratory, Stennis Space Center, MS 39529 (United States); Barry Maynard, J., E-mail: maynarjb@ucmail.uc.edu [Department of Geology, University of Cincinnati, Cincinnati, OH 45221-0013 (United States)

    2016-01-15

    This study provides a physicochemical assessment of manganese deposits on brass and lead components from two fully operational drinking water distributions systems. One of the systems was maintained with chlorine; the other, with secondary chloramine disinfection. Synchrotron-based in-situ micro X-ray adsorption near edge structure was used to assess the mineralogy. In-situ micro X-ray fluorescence mapping was used to demonstrate the spatial relationships between manganese and potentially toxic adsorbed metal ions. The Mn deposits ranged in thickness from 0.01 to 400 μm. They were composed primarily of Mn oxides/oxhydroxides, birnessite (Mn{sup 3+} and Mn{sup 4+}) and hollandite (Mn{sup 2+} and Mn{sup 4+}), and a Mn silicate, braunite (Mn{sup 2+} and Mn{sup 4+}), in varying proportions. Iron, chromium, and strontium, in addition to the alloying elements lead and copper, were co-located within manganese deposits. With the exception of iron, all are related to specific health issues and are of concern to the U.S. Environmental Protection Agency (U.S. EPA). The specific properties of Mn deposits, i.e., adsorption of metals ions, oxidation of metal ions and resuspension are discussed with respect to their influence on drinking water quality. - Highlights: • Oxidation and deposition of Mn deposits in drinking water distribution pipes • In-situ synchrotron-based μ-XANES and μ-XRF mapping • Toxic metal sorption in Mn deposits.

  19. Time varying effects in survival analysis

    DEFF Research Database (Denmark)

    Scheike, Thomas H.

    2002-01-01

    additive risk model; counting process; proportional hazards model; semi-parametric models; survival data; time-varying effects; nonparametric testing......additive risk model; counting process; proportional hazards model; semi-parametric models; survival data; time-varying effects; nonparametric testing...

  20. Fractal analysis of time varying data

    Science.gov (United States)

    Vo-Dinh, Tuan; Sadana, Ajit

    2002-01-01

    Characteristics of time varying data, such as an electrical signal, are analyzed by converting the data from a temporal domain into a spatial domain pattern. Fractal analysis is performed on the spatial domain pattern, thereby producing a fractal dimension D.sub.F. The fractal dimension indicates the regularity of the time varying data.

  1. Uranium mineralization and unconformities: how do they correlate? - A look beyond the classic unconformity-type deposit model?

    Science.gov (United States)

    Markwitz, Vanessa; Porwal, Alok; Campbell McCuaig, T.; Kreuzer, Oliver P.

    2010-05-01

    Uranium deposits are usually classified based on the characteristics of their host rocks and geological environments (Dahlkamp, 1993; OECD/NEA Red Book and IAEA, 2000; Cuney, 2009). The traditional unconformity-related deposit types are the most economical deposits in the world, with the highest grades amongst all uranium deposit types. In order to predict undiscovered uranium deposits, there is a need to understand the spatial association of uranium mineralization with structures and unconformities. Hydrothermal uranium deposits develop by uranium enriched fluids from source rocks, transported along permeable pathways to their depositional environment. Unconformities are not only separating competent from incompetent sequences, but provide the physico-chemical gradient in the depositional environment. They acted as important fluid flow pathways for uranium to migrate not only for surface-derived oxygenated fluids, but also for high oxidized metamorphic and magmatic fluids, dominated by their geological environment in which the unconformities occur. We have carried out comprehensive empirical spatial analyses of various types of uranium deposits in Australia, and first results indicate that there is a strong spatial correlation between unconformities and uranium deposits, not only for traditional unconformity-related deposits but also for other styles. As a start we analysed uranium deposits in Queensland and in particular Proterozoic metasomatic-related deposits in the Mount Isa Inlier and Late Carboniferous to Early Permian volcanic-hosted uranium occurrences in Georgetown and Charters Towers Regions show strong spatial associations with contemporary and older unconformities. The Georgetown Inlier in northern Queensland consists of a diverse range of rocks, including Proterozoic and early Palaeozoic metamorphic rocks and granites and late Palaeozoic volcanic rocks and related granites. Uranium-molybdenum (+/- fluorine) mineralization in the Georgetown inlier

  2. Advanced deposition model for thermal activated chemical vapor deposition

    Science.gov (United States)

    Cai, Dang

    Thermal Activated Chemical Vapor Deposition (TACVD) is defined as the formation of a stable solid product on a heated substrate surface from chemical reactions and/or dissociation of gaseous reactants in an activated environment. It has become an essential process for producing solid film, bulk material, coating, fibers, powders and monolithic components. Global market of CVD products has reached multi billions dollars for each year. In the recent years CVD process has been extensively used to manufacture semiconductors and other electronic components such as polysilicon, AlN and GaN. Extensive research effort has been directed to improve deposition quality and throughput. To obtain fast and high quality deposition, operational conditions such as temperature, pressure, fluid velocity and species concentration and geometry conditions such as source-substrate distance need to be well controlled in a CVD system. This thesis will focus on design of CVD processes through understanding the transport and reaction phenomena in the growth reactor. Since the in situ monitor is almost impossible for CVD reactor, many industrial resources have been expended to determine the optimum design by semi-empirical methods and trial-and-error procedures. This approach has allowed the achievement of improvements in the deposition sequence, but begins to show its limitations, as this method cannot always fulfill the more and more stringent specifications of the industry. To resolve this problem, numerical simulation is widely used in studying the growth techniques. The difficulty of numerical simulation of TACVD crystal growth process lies in the simulation of gas phase and surface reactions, especially the latter one, due to the fact that very limited kinetic information is available in the open literature. In this thesis, an advanced deposition model was developed to study the multi-component fluid flow, homogeneous gas phase reactions inside the reactor chamber, heterogeneous surface

  3. Mercury Wet Scavenging and Deposition Differences by Precipitation Type.

    Science.gov (United States)

    Kaulfus, Aaron S; Nair, Udaysankar; Holmes, Christopher D; Landing, William M

    2017-03-07

    We analyze the effect of precipitation type on mercury wet deposition using a new database of individual rain events spanning the contiguous United States. Measurements from the Mercury Deposition Network (MDN) containing single rainfall events were identified and classified into six precipitation types. Mercury concentrations in surface precipitation follow a power law of precipitation depth that is modulated by precipitation system morphology. After controlling for precipitation depth, the highest mercury deposition occurs in supercell thunderstorms, with decreasing deposition in disorganized thunderstorms, quasi-linear convective systems (QLCS), extratropical cyclones, light rain, and land-falling tropical cyclones. Convective morphologies (supercells, disorganized, and QLCS) enhance wet deposition by a factor of at least 1.6 relative to nonconvective morphologies. Mercury wet deposition also varies by geographic region and season. After controlling for other factors, we find that mercury wet deposition is greater over high-elevation sites, seasonally during summer, and in convective precipitation.

  4. Study of nozzle deposit formation mechanism for direct injection gasoline engines; Chokufun gasoline engine yo nozzle no deposit seisei kaiseki

    Energy Technology Data Exchange (ETDEWEB)

    Kinoshita, M.; Saito, A. [Toyota Central Research and Development Labs., Inc., Aichi (Japan); Matsushita, S. [Toyota Motor Corp., Aichi (Japan); Shibata, H. [Nippon Soken, Inc., Tokyo (Japan); Niwa, Y. [Denso Corp., Aichi (Japan)

    1997-10-01

    Nozzles in fuel injectors for direct injection gasoline engines are exposed to high temperature combustion gases and soot. In such a rigorous environment, it is a fear that fuel flow rate changes in injectors by deposit formation on nozzles. Fundamental factors of nozzle deposit formation were investigated through injector bench tests and engine dynamometer tests. Deposit formation processes were observed by SEM through engine dynamometer tests. The investigation results reveal nozzle deposit formation mechanism and how to suppress the deposit. 4 refs., 8 figs., 3 tabs.

  5. Shedding of ash deposits

    DEFF Research Database (Denmark)

    Zbogar, Ana; Frandsen, Flemming; Jensen, Peter Arendt;

    2009-01-01

    Ash deposits formed during fuel thermal conversion and located on furnace walls and on convective pass tubes, may seriously inhibit the transfer of heat to the working fluid and hence reduce the overall process efficiency. Combustion of biomass causes formation of large quantities of troublesome...... ash deposits which contain significant concentrations of alkali, and earth-alkali metals. The specific composition of biomass deposits give different characteristics as compared to coal ash deposits, i.e. different physical significance of the deposition mechanisms, lower melting temperatures, etc....... Low melting temperatures make straw ashes especially troublesome, since their stickiness is higher at lower temperatures, compared to coal ashes. Increased stickiness will eventually lead to a higher collection efficiency of incoming ash particles, meaning that the deposit may grow even faster...

  6. 四川盆地南部志留系龙马溪组富有机质页岩沉积环境的元素地球化学判别指标%Geochemistry Evaluation Index of Redox-sensitive Elements for Depositional Environments of Silurian Longmaxi Organic-rich Shale in the South of Sichuan Basin

    Institute of Scientific and Technical Information of China (English)

    王淑芳; 董大忠; 王玉满; 黄金亮; 蒲泊伶

    2014-01-01

    Redox-sensitive elements are the important indicators to determine the redox conditions of ancient ocean environments, and the trace and rare earth element ratios, such as V/Sr, V/Cr, Ni/Co, V/(V+Ni), U/Th, δU, Ce/Ce*and Eu/Eu*ratios, are commonly used as the indices of oxic and/or anoxic depositional environments. The analytic samples are selected from Silurian Longmaxi shale of Well Ning-203 in the south of Sichuan Basin, which is representative of regionally-distributed Longmaxi shale. The analysis of element geochemistry shows that the shale in the downmost part of Longmaxi Formation is organic-rich, which indicates the anoxic depositional environment and the shale in the upper part indicates the oxic environment. The relationships of values with V/Cr or Ni/Co ratios are all positively correlated, and enrichment of biological productivity-related elements reveals that preservation of organic-rich shale is related to anoxic environment. It is suggested that geochemical indices should be combined with sedimentary and paleontological features in studying the redox conditions of ancient sedimentary environments of shale.%氧化还原敏感元素是确定古海洋水体氧化还原环境的重要指标,常用的环境判别指标有U/Th, V/Sr, V/Cr, Ni/Co, V/(V+Ni),δU, Ce/Ce*, Eu/Eu*等元素比值。对四川盆地南部宁203井志留系龙马溪组页岩沉积环境的元素地球化学研究结果表明,龙马溪组底部富有机质页岩沉积于缺氧环境,上部为氧化环境。有机碳含量与V/Cr和Ni/Co呈正相关关系,且生物生产力相关元素富集,说明有机质保存与缺氧环境有关。认为在对页岩沉积水体氧化还原条件进行研究时,应将地球化学指标与沉积和古生物特征综合起来得出科学解释。

  7. Varying Alpha and the Electroweak Model

    CERN Document Server

    Kimberly, D; Kimberly, Dagny; Magueijo, Joao

    2003-01-01

    Inspired by recent claims for a varying fine structure constant, alpha, we investigate the effect of ``promoting coupling constants to variables'' upon various parameters of the standard model. We first consider a toy model: Proca's theory of the massive photon. We then explore the electroweak theory with one and two dilaton fields. We find that a varying alpha unavoidably implies varying W and Z masses. This follows from gauge invariance, and is to be contrasted with Proca' theory. For the two dilaton theory the Weinberg angle is also variable, but Fermi's constant and the tree level fermion masses remain constant unless the Higgs' potential becomes dynamical. We outline some cosmological implications.

  8. ElectroSpark Deposition

    Science.gov (United States)

    2007-01-25

    ElectroSpark Deposition Hard Chrome Alternatives Team Joint Cadmium Alternatives Team Canadian Hard Chrome Alternatives Team Joint Group on Pollution...00-2007 to 00-00-2007 4. TITLE AND SUBTITLE ElectroSpark Deposition 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S...Processes, Inc. ElectroSpark Deposition (ESD) Results of Materials Testing and Technology Insertion January 25, 2007 Advanced Surfaces And Processes, Inc. 3

  9. The Role of Deposition in Limiting the Hazard Extent of Dense-Gas Plumes

    Energy Technology Data Exchange (ETDEWEB)

    Dillon, M B

    2008-05-11

    Accidents that involve large (multi-ton) releases of toxic industrial chemicals and form dense-gas clouds often yield far fewer fatalities, casualties and environmental effects than standard assessment and emergency response models predict. This modeling study, which considers both dense-gas turbulence suppression and deposition to environmental objects (e.g. buildings), demonstrates that dry deposition to environmental objects may play a significant role in reducing the distance at which adverse impacts occur - particularly under low-wind, stable atmospheric conditions which are often considered to be the worst-case scenario for these types of releases. The degree to which the released chemical sticks to (or reacts with) environmental surfaces is likely a key parameter controlling hazard extents. In all modeled cases, the deposition to vertical surfaces of environmental objects (e.g. building walls) was more efficient in reducing atmospheric chemical concentrations than deposition to the earth's surface. This study suggests that (1) hazard extents may vary widely by release environment (e.g. grasslands vs. suburbia) and release conditions (e.g. sunlight or humidity may change the rate at which chemicals react with a surface) and (2) greenbelts (or similar structures) may dramatically reduce the impacts of large-scale releases. While these results are demonstrated to be qualitatively consistent with the downwind extent of vegetation damage in two chlorine releases, critical knowledge gaps exist and this study provides recommendations for additional experimental studies.

  10. A new look at liming as an approach to accelerate recovery from acidic deposition effects.

    Science.gov (United States)

    Lawrence, Gregory B; Burns, Douglas A; Riva-Murray, Karen

    2016-08-15

    Acidic deposition caused by fossil fuel combustion has degraded aquatic and terrestrial ecosystems in North America for over four decades. The only management option other than emissions reductions for combating the effects of acidic deposition has been the application of lime to neutralize acidity after it has been deposited on the landscape. For this reason, liming has been a part of acid rain science from the beginning. However, continued declines in acidic deposition have led to partial recovery of surface water chemistry, and the start of soil recovery. Liming is therefore no longer needed to prevent further damage, so the question becomes whether liming would be useful for accelerating recovery of systems where improvement has lagged. As more is learned about recovering ecosystems, it has become clear that recovery rates vary with watershed characteristics and among ecosystem components. Lakes appear to show the strongest recovery, but recovery in streams is sluggish and recovery of soils appears to be in the early stages. The method in which lime is applied is therefore critical in achieving the goal of accelerated recovery. Application of lime to a watershed provides the advantage of increasing Ca availability and reducing or preventing mobilization of toxic Al, an outcome that is beneficial to both terrestrial and aquatic ecosystems. However, the goal should not be complete neutralization of soil acidity, which is naturally produced. Liming of naturally acidic areas such as wetlands should also be avoided to prevent damage to indigenous species that rely on an acidic environment. Published by Elsevier B.V.

  11. The Role of Deposition in Limiting the Hazard Extent of Dense-Gas Plumes

    Energy Technology Data Exchange (ETDEWEB)

    Dillon, M B

    2008-05-11

    Accidents that involve large (multi-ton) releases of toxic industrial chemicals and form dense-gas clouds often yield far fewer fatalities, casualties and environmental effects than standard assessment and emergency response models predict. This modeling study, which considers both dense-gas turbulence suppression and deposition to environmental objects (e.g. buildings), demonstrates that dry deposition to environmental objects may play a significant role in reducing the distance at which adverse impacts occur - particularly under low-wind, stable atmospheric conditions which are often considered to be the worst-case scenario for these types of releases. The degree to which the released chemical sticks to (or reacts with) environmental surfaces is likely a key parameter controlling hazard extents. In all modeled cases, the deposition to vertical surfaces of environmental objects (e.g. building walls) was more efficient in reducing atmospheric chemical concentrations than deposition to the earth's surface. This study suggests that (1) hazard extents may vary widely by release environment (e.g. grasslands vs. suburbia) and release conditions (e.g. sunlight or humidity may change the rate at which chemicals react with a surface) and (2) greenbelts (or similar structures) may dramatically reduce the impacts of large-scale releases. While these results are demonstrated to be qualitatively consistent with the downwind extent of vegetation damage in two chlorine releases, critical knowledge gaps exist and this study provides recommendations for additional experimental studies.

  12. Posteruptive impacts of pyroclastic deposits from basaltic andesite stratovolcanoes on surface water composition

    Science.gov (United States)

    Genareau, K.; Cronin, S. J.; Stewart, C.; Bhattacharyya, S.; Donahoe, R.

    2016-05-01

    Volcanic ash deposition following explosive eruptions can pose significant hazards for water quality, human health, agriculture, and infrastructure functionality. Many studies have examined how fresh ash deposition may lower the pH of, and introduce a range of potentially toxic elements into, exposed surface waters. However, no study has yet determined the effects on water composition as a result of mechanical pyroclast disaggregation and production of new fresh particle surfaces and increasingly fine grained particles. Such disaggregation could result from natural posteruptive processes such as debris avalanches, lahars, or fluvial/aeolian transport and human activities such as cleanup efforts or mining of pyroclastic deposits. The posteruption time scales of pyroclast disaggregation may vary from months in moist tropical or temperate environments to years or decades in arid settings. Here we show, for the first time in experimental studies, that mechanical milling of pyroclasts will introduce a range of elements into exposed waters, including Al, which can be toxic at elevated levels, and Na, which increases the electrical conductivity of solutions. The pH of leaching solutions also increases by several log units. Such dramatic changes on the experimental scale may have implications for surface water composition in posteruptive settings, necessitating longer-term risk assessments for ecosystem health and consideration of the role of pyroclastic deposits in element cycling in volcanically active regions.

  13. Preliminary map of landslide deposits, Denver 1° by 2° Quadrangle, Colorado

    Science.gov (United States)

    Colton, Roger B.; Holligan, Jeffrey A.; Anderson, Larry W.

    1975-01-01

    Areas inferred to be underlain by landslide deposits resulting from landsliding, avalanching, block gliding, debris sliding or flowing, earthflows, mudflows, rocksliding, rockfalls, rotational slides, slab or flake sliding, slumping, talus accumulation, and translational sliding. Rock glacier deposits, colluvium, and solifluction deposits are included in some areas. Some till is mapped with landslide deposits because distinguishing these two deposits from one another is difficult: Furthermore, in some areas till has failed by landsliding and other types of mass movements. Movement within the deposits varies from none to rapid; rates of movement may also be variable in any given landslide within the same year. Ages of deposits' range from early Pleistocene to Holocene.

  14. On Biochemical Formation of Salt Deposits

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A water/salt system in an evaporative environment is both a physicochemical region and a biological one. All the parameters of the system, such as the salinity, temperature and CO2 partial pressure, are affected by halophilic bacteria. The system controls salt deposition but is modified by an accompanying ecological system; therefore it should be called a water/salt/biological system. Salt minerals result from accumulation of the remains of bacteria/algae, namely, bacteria/algae formation; whereas biological, biophysical and biochemical processes provide full evidence for organic involvement. Consequently, salt deposits should not be called purely chemical but biological/chemical ones. This new argument supplements and develops the traditional idea and helps perfect the mineralization theory of salts and even general deposits, thus giving guidance to prospecting for salt deposits.

  15. An Introduction to Atomic Layer Deposition

    Science.gov (United States)

    Dwivedi, Vivek H.

    2017-01-01

    Atomic Layer Deposition has been instrumental in providing a deposition method for multiple space flight applications. It is well known that ALD is a cost effective nanoadditive-manufacturing technique that allows for the conformal coating of substrates with atomic control in a benign temperature and pressure environment. Through the introduction of paired precursor gases, thin films can be deposited on a myriad of substrates from flat surfaces to those with significant topography. By providing atomic layer control, where single layers of atoms can be deposited, the fabrication of metal transparent films, precise nano-laminates, and coatings of nano-channels, pores and particles is achievable. The feasibility of this technology for NASA line of business applications range from thermal systems, optics, sensors, to environmental protection. An overview of this technology will be presented.

  16. Sediment-hosted Pb-Zn Deposits: a global perspective

    Science.gov (United States)

    Leach, David L.; Sangster, Donald F.; Kelley, Karen D.; Large, R; Garven, G.; Allen, Craig R.

    2005-01-01

    Sediment-hosted Pb-Zn deposits contain the world's greatest lead and zinc resources and dominate world production of these metals. They are a chverse group of ore deposits hosted by a wide variety of carbonate and siliciclastic roch that have no obviolls genetic association with igneous activity. A nmge of ore-fortl1ing processes in a vmiety of geologic and tectonic environments created these deposits over at least two billion years of Earth history. The metals were precipitated by basinal brines in synsedimentary and early diagenetic to low-grade metamorphic environments. The deposits display a broad range of relationships to enclosing host rocks that includes stratiform, strata-bound, and discordant ores. These ores are divided into two broad subt)1Jes: Mississippi Valley-type (MVT) and sedimentmy exhalative (SEDEX), Despite the "exhalative" component inherent in the term "SEDEX," in this manusclipt, direct evidence of an exhalite in the ore or alteration component is not essential for a deposit to be classified as SEDEX. The presence of laminated sulfides parallel to bedding is assumed to be permissive evidence for exhalative ores. The chstinction between some SEDEX and MVT depOSits can be quite subjective because some SEDEX ores replaced carbonate, whereas some MVT depOSits formed in an early diagenetic environment and display laminated ore textures. Geologic and resource information are presented for 248 depositS that provide a framework to describe ,mel compare these deposits. Nine of tlle 10 largest sediment-hosted Pb-Zn deposits are SEDEX, Of the deposits that contain at least 2.5 million metric tons (Mt), there are 35 SEDEX (excluding Broken Hill-type) deposits and 15 MVT (excluding Iris-type) deposits. Despite the skewed distribution of the deposit size, the two deposits types have an excellent correlation between total tonnage and tonnage of contained metal (Pb + Zn), with a fairly consistent ratio of about lO/l, regardless of the size of the deposit or

  17. The Effect of Deposition Time on Textured Magnesium Diboride Thick Films Fabricated by Electrophoretic Deposition

    Directory of Open Access Journals (Sweden)

    W. G. Mutia

    2004-12-01

    Full Text Available MgB2 pow