WorldWideScience

Sample records for chemical weathering processes

  1. Quantitative Chemical Indices of Weathered Igneous Rocks

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A study was conducted to compare the effectiveness of different weathering indices for characterising weathered igneous rocks of Hong Kong. Among eight chemical indices evaluated in this study, the Parker index has been found most suitable for a quantitative description of state of weathering. Based on geochemical results of 174 samples, the index decreases almost linearly with an increasing extent of weathering. The results enable a better understanding of the modification of geotechnical properties of igneous rocks associated with weathering processes.

  2. GEM-AQ, an on-line global multiscale chemical weather system: model description and evaluation of gas phase chemistry processes

    OpenAIRE

    Kaminski, J.W.; L. Neary; Struzewska, J.; Mcconnell, J. C.; A. Lupu; J. Jarosz; K. Toyota; Gong, S. L.; Côté, J; Liu, X; Chance, K.; Richter, A

    2007-01-01

    Tropospheric chemistry and air quality processes were implemented on-line in the Global Environmental Multiscale model. The integrated model, GEM-AQ, has been developed as a platform to investigate chemical weather at scales from global to urban. The model was exercised for five years (2001–2005) to evaluate its ability to simulate seasonal variations and regional distributions of trace gases such as ozone, nitrogen dioxide and carbon monoxide on the global scale. The model results ...

  3. High-Silica Rock Coatings on Mars: Constraining Secondary Silicate Mineralogy and Chemical Weathering Processes on Mars.

    Science.gov (United States)

    Kraft, M. D.; Michalski, J. R.; Sharp, T. G.

    2003-12-01

    Thermal Emission Spectrometer (TES) data have been fundamental to understanding Martian surface mineralogy. These data, however, require careful modeling based on laboratory spectroscopic measurements, and modeling of some minerals for Mars has been equivocal. Due to high degrees of spectral similarity, it is difficult to distinguishing silicate glass, clay minerals, zeolites, palagonitized glass, and other secondary products such as amorphous silica as components of surface rock spectra. Deciphering the nature of secondary mineral products on Mars is of key importance to understanding the role of water at the Martian surface over time. It is of central interest to distinguish primary glass from secondary silicate minerals, and secondary minerals from one another to better constrain the degree and mechanisms of aqueous alteration. Observations of Martian surface materials indicate some degree of atmosphere-water-rock interaction. These include nanophase ferric-iron oxides from visible/near-infrared spectroscopy, concentrated hematite deposits identified with TES, high water contents of rocks measured by the Alpha Proton X-ray Spectrometer, sulfate and halide minerals inferred from lander geochemical measurements, and carbonate minerals identified in Martian dust with TES data. Mass balance suggests that if there are oxides, salts, and carbonates there must also be secondary silicate phases present on Mars, which may be identifiable with TES. Identifying the types, distribution, and abundance (or absence) of secondary silicates will enable better constrains to be placed on Martian chemical weathering processes and the role water has played at the Martian surface. We suggest that rock coatings dominated by amorphous silica are geologically reasonable for Mars and may be consistent with TES data. Laboratory measurements of silica-coated rocks show that thin, micrometer-scale silica coatings have a substantial impact on rock spectra. Consequently, if authegenic

  4. GEM-AQ, an on-line global multiscale chemical weather system: model description and evaluation of gas phase chemistry processes

    Directory of Open Access Journals (Sweden)

    J. W. Kaminski

    2007-10-01

    Full Text Available Tropospheric chemistry and air quality processes were implemented on-line in the Global Environmental Multiscale model. The integrated model, GEM-AQ, has been developed as a platform to investigate chemical weather at scales from global to urban. The model was exercised for five years (2001–2005 to evaluate its ability to simulate seasonal variations and regional distributions of trace gases such as ozone, nitrogen dioxide and carbon monoxide on the global scale. The model results presented are compared with observations from satellites, aircraft measurement campaigns and balloon sondes.

  5. Sr isotope evolution during chemical weathering of granites -- impact of relative weathering rates of minerals

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The Sr isotopic systematics in the weathering profiles of biotite granite and granite porphyry in southern Jiangxi Province were investigated. The results showed that during the chemical weathering of granites, remarked fractionation occurred between Rb and Sr. During the early stages of chemical weathering of granites, the released Sr/Si and Sr/Ca ratios are larger than those of the parent rocks, and the leaching rate of Sr is higher than those of Si, Ca, K, Rb, etc. Dynamic variations in relative weathering rates of the main Sr-contributing minerals led to fluctuation with time in 87Sr/86Sr ratios of inherent and released Sr in the weathering crust of granite. Successive weathering of biotite, plagioclase and K-feldspar made 87Sr/86Sr ratios in the weathering residues show such a fluctuation trend as to decrease first, increase, and then decrease again till they maintain stable. This work further indicates that when Sr isotopes are used to trace biogeochemical processes on both the catchment and global scales, one must seriously take account of the prefer-ential release of Sr from dissolving solid phase and the fluctuation of 87Sr/86Sr ratios caused by the variations of relative weathering rates of Sr-contributing minerals.

  6. Chemical weather forecasting: a new concept of integrated modelling

    OpenAIRE

    Baklanov, A.

    2010-01-01

    During the last decade a new field of atmospheric modelling – the chemical weather forecasting (CWF) – is quickly developing and growing. However, in the most of the current studies and publications, this field is considered in a simplified concept of the off-line running chemical transport models with operational numerical weather prediction (NWP) data as a driver. A new concept and methodology considering the chemical weather as two-way interacting meteorologic...

  7. Provenance control on chemical indices of weathering (Taiwan river sands)

    Science.gov (United States)

    Garzanti, Eduardo; Resentini, Alberto

    2016-05-01

    Geochemical parameters obtained from the analysis of sediments and sedimentary rocks are widely used to infer weathering and paleo-weathering conditions in source areas. Chemical indices of weathering, however, may not reflect weathering only, or even principally. The concentration of chemical elements in terrigenous sediments is constrained by the original mineralogy of source rocks, and is thus provenance-dependent. Moreover, the mineralogy and consequently the geochemistry of sediments may undergo substantial modifications by diverse physical processes during transport and deposition, including recycling and hydraulic sorting by size, density or shape, and/or by chemical dissolution and precipitation during diagenesis. Around the island of Taiwan, temperature and rainfall are consistently high and relatively homogeneous, and no significant correlation is observed between geochemical and climatic parameters. Physical erosion, fostered by landslides induced by frequent earthquakes and typhoons, prevails because of high relief and extreme rates of tectonic uplift. In such a dynamic orogenic setting, all chemical indices of weathering are controlled principally by the geology of source terranes. Sedimentaclastic and metasedimentaclastic sands carried by western Taiwan rivers draining the pro-wedge display the strongest depletion in Na, Ca, Mg and Sr relative to average upper continental crust, and no depletion or even enrichment in K, Rb and Ba. Low WIP indices reflect erosion of phyllosilicate-dominated rocks in the Slate Belt and extensive recycling of clastic rocks exposed in the Western Foothills. Instead, metamorphiclastic sands carried by eastern Taiwan rivers draining the retro-wedge show no depletion or even enrichment in Mg and Ca, and low CIA and PIA, reflecting contributions from the Tailuko Belt and Coastal Range. Volcaniclastic sands have the same CIA values of their andesitic source rocks (47 ± 1 versus 47 ± 7), indicating that weathering is

  8. Weak chemical weathering during the Little Ice Age recorded by lake sediments

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Low magnetic susceptibility, low Sr content and hence high Rb/Sr ratio in the lake sediment sequence indicate a weak chemical weathering process under arid and cold climate of the Little Ice Age in a single closed lake watershed. According to different geochemical behavior between rubidium and strontium in earth surface processes, variation of Rb/Sr ratios in the lake sediment sequence can be used as an effective geochemical proxy with definite climatic significance of chemical weathering in watershed. Unlike chemical weathering process in tropic zone and modern temperate-humid climate, concordant changes in both Sr content and magnetic susceptibility with d18O values of Dunde ice core suggest that the weak chemical weathering was controlled by air temperature during the Little Ice Age maximum. After the Little Ice Age, chemical weathering intensity was controlled also gradually by precipitation with increasing in temperature.

  9. Allophane on Mars: Significance for Chemical Weathering and Soil Development

    Science.gov (United States)

    Kraft, M. D.; Rampe, E. B.; Sharp, T. G.; Ming, D. W.; Golden, D. C.; Christensen, P. R.

    2010-12-01

    It has been suggested that allophane or related poorly crystalline aluminosilicates are present on Mars, and that they comprise the high-silica phase detected by the Thermal Emission Spectrometer (TES) in Surface Type 2 materials (Kraft et al., 2003; Michalski et al., 2005). Using new laboratory spectra of allophanic materials, we (Rampe et al., this meeting) have detected allophane on the Martian surface via spectral modeling of TES data. We find that ST2 materials in the Northern Plains are consistent with a significant amount of high-silica allophane-like materials. In addition, we find that allophane may be present in some areas of the ancient highlands (TES Surface Type 1), but spectra of those regions are more consistent with aluminous allophane. The presence of allophane and its chemical variability have important implications for chemical weathering and soil development on Mars. Allophane-like materials are amorphous or poorly crystalline hydrous aluminosilicates formed from chemical weathering of glasses, feldspars, and other silicates (cf. Parfitt, 2009). True allophane is a combination of SiO2, Al2O3 and H2O, where Al:Si ranges from ~0.5-2. Aluminosilicate gels are amorphous and chemically similar to allophane but can have higher SiO2 contents. The presence of allophane indicates low-temperature chemical weathering and provides constraints on alteration conditions, limiting pH to circum-neutral (~4.5-8). Our model results indicate that weathering occurred in the relatively young northern plains of Mars. The high-silica allophane-like material present there implies little silica mobility through the soil column, which suggests that weathering involved small amounts of liquid water, consistent with our previous models of weathering in ice-rich soils (Kraft et al., 2007). The aluminous allophane indicated by our spectral models to be present in the highlands suggest that those regions experienced greater amounts of SiO2 leaching and weathering in those

  10. Global CO2-consumption by chemical weathering: What is the contribution of highly active weathering regions?

    OpenAIRE

    Hartmann, Jens; Jansen, N; Dürr, H. H.; Kempe, S.; Köhler, Peter

    2009-01-01

    CO2-consumption by chemical weathering of silicates and resulting silicate/carbonate weathering ratios influences the terrestrial lateral inorganic carbon flux to the ocean and long-term climate changes. However, little is known of the spatial extension of highly active weathering regions and their proportion of global CO2-consumption. As those regions may be of significant importance for global climate change, global CO2-consumption is calculated here at high resolution, to adequately repres...

  11. Chemical weathering and chemical runoffs in the seashore granite hills in South China

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Surface runoffs and the contents of major ions and dissolved silicon were surveyed and analyzed based on weekly sampling for one year in a granite watershed of Zhuhai City, Guangdong Province. The results demonstrated that the slope runoff played an essential role in feeding the rivulet during precipitation, whereas the groundwater was more important for the rivulet in the non-raining stages. Dissolved silicon, Na+, HCO3-, and Clions constituted the major chemical components of the rivulet water. Atmospheric CO2 and H2SO4 sourced from the oxidation of pyrite were the main erosive mediums in the natural chemical weathering. Natural chemical weathering, the wet and dry deposition of sea-salt, and acids precipitation contributed approximately equal shares of anions to the rivulet water. The ratio of NO3- to SO42- was more than 1.0 in the runoff of the studied seashore watershed, whereas it is less than 1.0 in the Xijiang River that is adjacent to the study area. This implied that the chemical composition of runoff is controlled mainly by the differences in atmospheric acid precipitation caused by human activities and lithology within the catchments under the same bio-climate zone. The CO2 flux consumed by the rock chemical weathering processes within the seashore granite watershed in South China was (0.35-1.37)×105 mol km-2 a-1.

  12. Biofilm supported increase of chemical weathering and decrease of chemical denudation in pine growth experiments

    Science.gov (United States)

    Balogh, Z.; Keller, C.; Gill, R. A.

    2006-12-01

    Vascular plants and associated microbial communities produced biofilm coatings increase weathering by extending contact periods of minerals with low pH liquids. We performed an experiment to isolate the effects of ectomycorrhiza-forming fungi and ectomycorrhiza- helper bacteria on chemical weathering and chemical denudation (i.e. chemical erosion), and their effects on these fluxes in association with red pine as a host. The study was conducted in a growth chamber using sandy growth medium in replicated flow-through columns. Biotite and anorthite supplied Ca, Mg and K. Concentrations of these cations were measured in input and output solutions, in tree biomass and on exchangeable cation sites of the growth medium; then weathering and denudation fluxes were estimated by mass-balance. In addition, mineral surface changes, biofilm cover and microbial attachment to surfaces were investigated with scanning electron microscopy. The column experiment demonstrated that both bacteria and fungi had a large weathering potential for Ca- bearing minerals, but the microbial communities were not able to regulate denudation losses without a vascular host. Chemical weathering and denudation were about equal in each microbe-only treatment. By the second 6 months of the experiment treatment effects became significant for the seedling systems (p<0.005). The ectomycorrhizal treatments produced the greatest weathering and least denudation, but non- ectomycorrhizal seedlings lowered denudation as well. The differences between the fluxes were significant in both ectomycorrhizal and non-ectomycorrhizal treatments, but the ectomycorrhizal treatment difference was larger, while abiotic weathering was less and equaled the abiotic denudation flux. The ability to retard denudation in both ectomycorrhizal and non-ectomycorrhizal treatment was linked to biofilm formation on mineral surfaces. An ectomycorrhizal hyphal network, as part of the biofilm or covered by the biofilm, was apparently able

  13. Sulfide mineralization: Its role in chemical weathering of Mars

    Science.gov (United States)

    Burns, Roger G.

    1988-01-01

    Pyrrhotite-pentlandite assemblages in mafic and ultramafic igneous rocks may have contributed significantly to the chemical weathering reactions that produced degradation products in the Martian regolith. By analogy with terrestrial processes, a model is proposed whereby supergene alteration of these primary Fe-Ni sulfides on Mars has generated secondary sulfides (e.g., pyrite) below the water table and produced acidic groundwater containing high concentrations of dissolved Fe, Ni and sulfate ions. The low pH solutions also initiated weathering reactions of igneous feldspars and ferromagnesian silicates to form clay silicate and ferric oxyhydroxide phases. Near-surface oxidation and hydrolysis of ferric sulfato- and hydroxo-complex ions and sols formed gossans above the water table consisting of poorly crystalline hydrated ferric sulfates (e.g., jarosite), oxides (ferrihydrite, goethite) and silica (opal). Underlying groundwater, now permafrost, contains hydroxo sulfato complexes of Fe, Al, Mg, Ni, etc., which may be stabilized in frozen acidic solutions beneath the surface of Mars. Sublimation of permafrost may replenish colloidal ferric oxides, sulfates and phyllosilicates during dust storms on Mars.

  14. Influence of chemical weathering and aging of iron oxides on the potential iron solubility of Saharan dust during simulated atmospheric processing

    OpenAIRE

    Z. B. Shi; M. D. Krom; S. Bonneville; A. R. Baker; C. Bristow; N. Drake; G. Mann; K. Carslaw; J. B. McQuaid; T. Jickells; Liane G. Benning

    2011-01-01

    The flux of bioavailable Fe from mineral dust to the surface ocean is controlled not only by the processes in the atmosphere but also by the nature and source of the dust. In this study, we investigated how the nature of Fe minerals in the dust affects its potential Fe solubility (Fe-psol) employing traditional and modern geochemical, mineralogical, and microscopic techniques. The chemical and mineralogical compositions, particularly Fe mineralogy, in soil samples as dust precursors collected...

  15. Chemical element transfer of weathering granite regolith in the Three Gorges Dam region of Yangtze River

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Clearing up sediment and regolith on the foundation of the dam in the Three Gorges of the Yangtze River in 1999, riverbed were exposed. On the basis of weathering granite regolith sampled from different portions of the valley landforms, by analysing total chemical contents with X rays fluorescent slice and calculating proper value of chemical element transferring ratio and intensity, the transferring law of chemical elements in different portions of the landforms were concluded: 1) In various landforms of the river valley, the process of desilication is not distinct; 2) in weathering granite regolith of riverbed, easy soluble CaO and MgO are relatively enriched whereas A1203 tends to decrease. The enriching rate of Fe203 is the greatest in various landforms of the river valley; 3) in weathering granite regolith of flood-plain, K20 and MgO contents are relatively enriched; 4) the weathering granite regolith of valley slope is a typical north subtropical weathering regolith, and its chemical weathering degree is in the transition phase from early to middle period; and 5) there is an opposite layer where K20 is relatively leaching and Na20 relatively enriching in 6.5 m depth of all weathering granite regolith.

  16. Global CO2-consumption by chemical weathering: What is the contribution of highly active weathering regions?

    Science.gov (United States)

    Hartmann, Jens; Jansen, Nils; Dürr, Hans H.; Kempe, Stephan; Köhler, Peter

    2010-05-01

    CO2-consumption by chemical weathering of silicates and resulting silicate/carbonate weathering ratios influences the terrestrial lateral inorganic carbon flux to the ocean and long-term climate changes. However, little is known of the spatial extension of highly active weathering regions and their proportion of global CO2-consumption. As those regions may be of significant importance for global climate change, global CO2-consumption is calculated here at high resolution, to adequately represent them. In previous studies global CO2-consumption is estimated using two different approaches: i) a reverse approach based on hydrochemical fluxes from large rivers and ii) a forward approach applying spatially explicit a function for CO2-consumption. The first approach results in an estimate without providing a spatial resolution for highly active regions and the second approach applied six lithological classes while including three sediment classes (shale, sandstone and carbonate rock) based at a 1° or 2° grid resolution. It remained uncertain, if the applied lithological classification schemes represent adequately CO2-consumption from sediments on a global scale (as well as liberation of other elements like phosphorus or silicon by chemical weatheirng). This is due to the large variability of sediment properties, their diagenetic history and the contribution from carbonates apparent in silicate dominated lithological classes. To address these issues, a CO2-consumption model, trained at high-resolution data, is applied here to a global vector based lithological map with 15 lithological classes. The calibration data were obtained from areas representing a wide range of weathering rates. Resulting global CO2-consumption by chemical weathering is similar to earlier estimates (237 Mt C a-1) but the proportion of silicate weathering is 63%, and thus larger than previous estimates (49 to 60%). The application of the enhanced lithological classification scheme reveals that it

  17. Geochemical investigation of weathering processes in a forested headwater catchment: Mass-balance weathering fluxes

    Science.gov (United States)

    Jones, B.F.; Herman, J.S.

    2008-01-01

    Geochemical research on natural weathering has often been directed towards explanations of the chemical composition of surface water and ground water resulting from subsurface water-rock interactions. These interactions are often defined as the incongruent dissolution of primary silicates, such as feldspar, producing secondary weathering products, such as clay minerals and oxyhydroxides, and solute fluxes (Meunier and Velde, 1979). The chemical composition of the clay-mineral product is often ignored. However, in earlier investigations, the saprolitic weathering profile at the South Fork Brokenback Run (SFBR) watershed, Shenandoah National Park, Virginia, was characterized extensively in terms of its mineralogical and chemical composition (Piccoli, 1987; Pochatila et al., 2006; Jones et al., 2007) and its basic hydrology. O'Brien et al. (1997) attempted to determine the contribution of primary mineral weathering to observed stream chemistry at SFBR. Mass-balance model results, however, could provide only a rough estimate of the weathering reactions because idealized mineral compositions were utilized in the calculations. Making use of detailed information on the mineral occurrence in the regolith, the objective of the present study was to evaluate the effects of compositional variation on mineral-solute mass-balance modelling and to generate plausible quantitative weathering reactions that support both the chemical evolution of the surface water and ground water in the catchment, as well as the mineralogical evolution of the weathering profile. ?? 2008 The Mineralogical Society.

  18. A Physically Based Coupled Chemical and Physical Weathering Model for Simulating Soilscape Evolution

    Science.gov (United States)

    Willgoose, G. R.; Welivitiya, D.; Hancock, G. R.

    2015-12-01

    A critical missing link in existing landscape evolution models is a dynamic soil evolution models where soils co-evolve with the landform. Work by the authors over the last decade has demonstrated a computationally manageable model for soil profile evolution (soilscape evolution) based on physical weathering. For chemical weathering it is clear that full geochemistry models such as CrunchFlow and PHREEQC are too computationally intensive to be couplable to existing soilscape and landscape evolution models. This paper presents a simplification of CrunchFlow chemistry and physics that makes the task feasible, and generalises it for hillslope geomorphology applications. Results from this simplified model will be compared with field data for soil pedogenesis. Other researchers have previously proposed a number of very simple weathering functions (e.g. exponential, humped, reverse exponential) as conceptual models of the in-profile weathering process. The paper will show that all of these functions are possible for specific combinations of in-soil environmental, geochemical and geologic conditions, and the presentation will outline the key variables controlling which of these conceptual models can be realistic models of in-profile processes and under what conditions. The presentation will finish by discussing the coupling of this model with a physical weathering model, and will show sample results from our SSSPAM soilscape evolution model to illustrate the implications of including chemical weathering in the soilscape evolution model.

  19. Chemical weathering in active mountain belts controlled by stochastic bedrock landsliding

    Science.gov (United States)

    Emberson, Robert; Hovius, Niels; Galy, Albert; Marc, Odin

    2016-01-01

    A link between chemical weathering and physical erosion exists at the catchment scale over a wide range of erosion rates. However, in mountain environments, where erosion rates are highest, weathering may be kinetically limited and therefore decoupled from erosion. In active mountain belts, erosion is driven by bedrock landsliding at rates that depend strongly on the occurrence of extreme rainfall or seismicity. Although landslides affect only a small proportion of the landscape, bedrock landsliding can promote the collection and slow percolation of surface runoff in highly fragmented rock debris and create favourable conditions for weathering. Here we show from analysis of surface water chemistry in the Southern Alps of New Zealand that weathering in bedrock landslides controls the variability in solute load of these mountain rivers. We find that systematic patterns in surface water chemistry are strongly associated with landslide occurrence at scales from a single hillslope to an entire mountain belt, and that landslides boost weathering rates and river solute loads over decades. We conclude that landslides couple erosion and weathering in fast-eroding uplands and, thus, mountain weathering is a stochastic process that is sensitive to climatic and tectonic controls on mass wasting processes.

  20. Does runoff or temperature control chemical weathering rates?

    International Nuclear Information System (INIS)

    Highlights: → The rate chemical weathering is affected by both temperature and runoff. Separating out these two factors is challenging because runoff tends to increase with increasing temperature. → In this study, natural river water samples collected on basaltic catchments over a five year period are used together with experimentally derived dissolution rate model for basaltic glass to pull apart the effects of runoff and temperature. → This study shows that the rate of chemical denudation is controlled by both temperature and runoff, but is dominated by runoff. - Abstract: The rate of chemical denudation is controlled by both temperature and runoff. The relative role of these two factors in the rivers of NE Iceland is determined through the rigorous analysis of their water chemistry over a 5-a period. River catchments are taken to be analogous to laboratory flow reactors; like the fluid in flow reactors, the loss of each dissolved element in river water is the sum of that of the original rainwater plus that added from kinetically controlled dissolution and precipitation reactions. Consideration of the laboratory determined dissolution rate behaviour of basalts and measured water chemistry indicates that the maximum effect of changing temperature on chemical denudation in the NE Icelandic rivers was 5-25% of the total change, whereas that of runoff was 75-95%. The bulk of the increased denudation rates with runoff appear to stem from an increase in reactive surface area for chemical weathering of catchment solids.

  1. Effect of Weather on the Predicted PMN Landmine Chemical Signature for Kabul, Afghanistan

    Energy Technology Data Exchange (ETDEWEB)

    WEBB, STEPHEN W.; PHELAN, JAMES M.

    2002-11-01

    Buried landmines are often detected through the chemical signature in the air above the soil surface by mine detection dogs. Environmental processes play a significant role in the chemical signature available for detection. Due to the shallow burial depth of landmines, the weather influences the release of chemicals from the landmine, transport through the soil to the surface, and degradation processes in the soil. The effect of weather on the landmine chemical signature from a PMN landmine was evaluated with the T2TNT code for Kabul, Afghanistan. Results for TNT and DNT gas-phase and soil solid-phase concentrations are presented as a function of time of the day and time of the year.

  2. UNDERSTANDING SEVERE WEATHER PROCESSES THROUGH SPATIOTEMPORAL RELATIONAL RANDOM FORESTS

    Data.gov (United States)

    National Aeronautics and Space Administration — UNDERSTANDING SEVERE WEATHER PROCESSES THROUGH SPATIOTEMPORAL RELATIONAL RANDOM FORESTS AMY MCGOVERN, TIMOTHY SUPINIE, DAVID JOHN GAGNE II, NATHANIEL TROUTMAN,...

  3. Weathering processes in uranium tailings and the migration of contaminants

    International Nuclear Information System (INIS)

    The degree to which weathering affects the tailings and the subsequent release and mobilization of the contaminants depends on a number of important factors: (a) Characterization of the tailings: The mineralogy and associated gangue minerals, the leach process, particle size, type and nature of the sulphide minerals, tailings treatment (i.e. dewatering, neutralization), the chemical nature of slurry water (pH, Eh, ions). (b) Oxidation reactions involved in the conversion of sulphides to sulphuric acid, whether by chemical or bacterial oxidation. (c) The role of bacteria present, whether iron oxidizing or sulphate reducing, and the relative population of the microorganisms. (d) Stability of Ba(Ra)So4 precipitation in the tailings with respect to the effect of weathering and bacteria, particularly that of the sulphate reducing microorganisms. (e) The influences of hydrology and geology relating to the siting of the tailings; dam construction; method of tailings deposition; amount of groundwater in and out of the tailings; amount of process water remaining with the solids which affect the quantity and quality of the seepage; rainfall, atmospheric temperature, seasonal flooding, dissolved O2 or other gases; porosity and permeability; geochemical processes of sorption, desorption, precipitation and redissolution; capillary forces, electrolyte concentrations and salt formation. (f) Migration of salts upward by capillary action; (g) Static leach tests on tailings can provide valuable information as to some of the chemistry occurring within the tailings impoundments. However, more valid information can be gained by long term controlled weathering tests in lysimeters where a number of parameters can be monitored and assessed simultaneously. 68 refs, 18 figs, 15 tabs

  4. Chemical process hazards analysis

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-02-01

    The Office of Worker Health and Safety (EH-5) under the Assistant Secretary for the Environment, Safety and Health of the US Department (DOE) has published two handbooks for use by DOE contractors managing facilities and processes covered by the Occupational Safety and Health Administration (OSHA) Rule for Process Safety Management of Highly Hazardous Chemicals (29 CFR 1910.119), herein referred to as the PSM Rule. The PSM Rule contains an integrated set of chemical process safety management elements designed to prevent chemical releases that can lead to catastrophic fires, explosions, or toxic exposures. The purpose of the two handbooks, ``Process Safety Management for Highly Hazardous Chemicals`` and ``Chemical Process Hazards Analysis,`` is to facilitate implementation of the provisions of the PSM Rule within the DOE. The purpose of this handbook ``Chemical Process Hazards Analysis,`` is to facilitate, within the DOE, the performance of chemical process hazards analyses (PrHAs) as required under the PSM Rule. It provides basic information for the performance of PrHAs, and should not be considered a complete resource on PrHA methods. Likewise, to determine if a facility is covered by the PSM rule, the reader should refer to the handbook, ``Process Safety Management for Highly Hazardous Chemicals`` (DOE- HDBK-1101-96). Promulgation of the PSM Rule has heightened the awareness of chemical safety management issues within the DOE. This handbook is intended for use by DOE facilities and processes covered by the PSM rule to facilitate contractor implementation of the PrHA element of the PSM Rule. However, contractors whose facilities and processes not covered by the PSM Rule may also use this handbook as a basis for conducting process hazards analyses as part of their good management practices. This handbook explains the minimum requirements for PrHAs outlined in the PSM Rule. Nowhere have requirements been added beyond what is specifically required by the rule.

  5. Rock weathering Tendency at Different Stages of Soil—Forming Processes in Fildes Peninsula,Antarctic

    Institute of Scientific and Technical Information of China (English)

    CHENJIE; GONGZITONG

    1996-01-01

    From the view of energy state of material,this paper introduces a concept a concept of weathering potential in carrying out quantitative calculation of the relevant products at different stages of rock-weathering and primary soil-forming processes,elaborates respectively on weathering degree in the bio-weathering layer of rocks and during the formation of soil material and clay,and evaluats the further tendency of weathering in the above-mentioned stages.The authors have discovered that the scales of weathering potential of the materials increase successively in the three stages,which indicates that the products in the above-mentioned three stages must have undergone stronger and stronger weathering in the primitive forming process of soil in Fildes Peninsula,Antarctic.But,Because of relatively weak chemical weathering,it is reasonable that there are much more skeleton grains and little clay in priamry soils in this region.Meanwhile the authors have also verified that the weathering potential of crde rock determines to some extent decrease in the products' weathering potential in the different stages in primary soil-forming,thereby plays an important role in the genesis and development of the primary soil in the studied area.

  6. Insights into chemical weathering of the upper continental crust from the geochemistry of ancient glacial diamictites

    Science.gov (United States)

    Li, Su; Gaschnig, Richard M.; Rudnick, Roberta L.

    2016-03-01

    Glacial diamictites, with ages ranging from ∼2900 to 0.01 Ma, record the changing composition of the upper continental crust through time (Gaschnig et al., 2014). Li concentrations and isotopic compositions, combined with Pb isotopic compositions, chemical index of alteration (CIA) values and relative Sr concentrations are used here to assess the degree of chemical weathering recorded in these deposits and the origin of this signature. The δ7Li values of most of the diamictites (ranging from -3.9 to +3.5) are lower than those of mantle-derived basalts (+3.7 ± 2, 2σ), and the low δ7Li values are generally accompanied by high CIA and low Sr/Sr∗ values (or Sr depletion factor, Sr/Sr∗ = Sr/(Ce∗Nd)0.5), reflecting a weathering signature that may have derived from pre-depositional, syn-depositional, and/or post-depositional weathering processes. Profiles through three glacial diamictites with relatively high CIA (a fresh road cut of the Neoproterozoic Nantuo Formation (CIA = 62-69), and drill cores through the Paleoproterozoic Timeball Hill (CIA = 66-75) and Duitschland Formations (CIA = 84-91)) do not show evidence of significant post-depositional weathering. High Th/U, reflecting loss of uranium during oxidative weathering, is seen in all Paleozoic and Neoproterozoic diamictites and a few Paleoproterozoic deposits. Pb isotopic systematics suggest that this signature was largely inherited from preexisting crust, although a subset of samples (the Neoproterozoic Konnarock, Paleozoic Dwyka, and several of the Paleoproterozoic Duitschland samples) appears to have experienced post-depositional U loss. Modern glaciomarine sediments record little weathering (CIA = 47, Sr/Sr∗ = 0.7, δ7Li = +1.8), consistent with the cold temperatures accompanying glacial periods, and suggesting that limited syn-depositional weathering has occurred. Thus, the chemical weathering signature observed in ancient glacial diamictites appears to be largely inherited from the upper

  7. Questa Baseline and Pre-mining Ground-Water Quality Investigation, 7. A Pictorial Record of Chemical Weathering, Erosional Processes, and Potential Debris-flow Hazards in Scar Areas Developed on Hydrothermally Altered Rocks

    Science.gov (United States)

    Plumlee, Geoffrey S.; Ludington, Steve; Vincent, Kirk R.; Verplanck, Philip L.; Caine, Jonathan S.; Livo, K. Eric

    2009-01-01

    Erosional scar areas developed along the lower Red River basin, New Mexico, reveal a complex natural history of mineralizing processes, rapid chemical weathering, and intense physical erosion during periodic outbursts of destructive, storm-induced runoff events. The scar areas are prominent erosional features with craggy headwalls and steep, denuded slopes. The largest scar areas, including, from east to west, Hottentot Creek, Straight Creek, Hansen Creek, Lower Hansen Creek, Sulfur Gulch, and Goat Hill Gulch, head along high east-west trending ridges that form the northern and southern boundaries of the lower Red River basin. Smaller, topographically lower scar areas are developed on ridge noses in the inner Red River valley. Several of the natural scar areas have been modified substantially as a result of large-scale open-pit and underground mining at the Questa Mine; for example, much of the Sulfur Gulch scar was removed by open pit mining, and several scars are now partially or completely covered by mine waste dumps.

  8. Controls on chemical weathering on a mountainous volcanic tropical island: Guadeloupe (French West Indies)

    Science.gov (United States)

    Dessert, C.; Lajeunesse, E.; Lloret, E.; Clergue, C.; Crispi, O.; Gorge, C.; Quidelleur, X.

    2015-12-01

    Guadeloupe Island is a natural laboratory, ideally suited to the study of biogeochemical processes in tropical and mountainous volcanic environments. The island's east-west rainfall gradient (1200-8000 mm/yr) is superimposed on a north-south age gradient (2.7 Ma to present), providing a unique opportunity to investigate the influence of rainfall and rock age on the chemical weathering of volcanic terrains. Taking advantage of this configuration, we present the first temporal survey (2007-2013) of the geochemical composition of the dissolved load of rain and river waters in Guadeloupe. Our data demonstrate that the chemical composition of river water is influenced by rainfall abundance, hydrothermal alteration (from active or fossilized volcanic systems) and interactions between water and minerals during chemical weathering processes. The contribution of rain to the overall chemical balance is especially significant in the older northern part of the island, where the ferralitic soils are base-cation-depleted. Between 15% and 65% of the Ca or Mg riverine budgets comes from atmospheric deposits, highlighting the major role of rainfall in the geochemical budgets of small tropical and mountainous watersheds. The river water dataset indicates that different chemical weathering processes dominate the budget depending on the age of the local bedrock. In the younger, southern part of the island, a pool of easily-weatherable andesitic minerals from the bedrock dominates. The contribution from this pool decreases significantly (to 5-15 wt.% of the bulk soil) towards the older terrains in the north. The northern rivers are characterized by low Ca/Mg ratios (0.5-1.0), intermediate between those of fresh rocks (1.7-3.3) and soil (0.1). Weathering in the northern part of the island is therefore dominated by the dissolution of depleted secondary minerals into soils. The Ca/Mg ratio of the river water increases from north to south, eventually reaching values similar to those of the

  9. Water geochemistry of the Xijiang basin rivers, South China: Chemical weathering and CO2 consumption

    International Nuclear Information System (INIS)

    Research highlights: → The Xijiang River is the second largest river in China and flows through a large carbonate rock region in South China. → Sulfuric acid, which emanate from acid precipitation and the oxidation of sulfide minerals, is involved as a proton donor in weathering reactions in the Xijiang basin. → Calculated results show that the contribution of cations from rock weathering induced by sulfuric acid accounts for approximately 11.2%. → The flux of CO2 released into the atmosphere is approximately 0.41 x 1012 gC yr-1 produced by sulfuric acid-induced carbonate weathering in the Xijiang basin. → Sulfuric acid-induced carbonate weathering could counterbalance a significant part of the CO2 consumed by silicate weathering. - Abstract: The Xijiang River, the mainstream of the Zhujiang (Pearl) River, which is the second largest river in China in terms of discharge, flows through a large carbonate rock region in South China. The chemical and Sr isotopic compositions of the Xijiang waters were determined during the high-flow season in order to understand the chemical weathering processes, associated CO2 consumption and anthropogenic influences within the carbonate-dominated basin. The major ion compositions of the river waters are characterized by the dominance of Ca2+, Mg2+, HCO3- and are significantly rich in SO42-. The SO42- is mainly derived from the oxidation of sulfide minerals and acid precipitation caused by coal combustion. Chemical and Sr isotopic compositions of the river waters indicate that four reservoirs (carbonates, silicates, evaporites and anthropogenic inputs) contribute to the total dissolved loads. The chemical weathering rates of carbonates and silicates for the Xijiang basin are estimated to be approximately 78.5 and 7.45 ton km-2 a-1, respectively. The total chemical weathering rate of rocks for the Xijiang basin is approximately 86.1 ton km-2 a-1 or 42 mm ka-1, which is much higher than global mean values. The budgets of CO2

  10. The Neogene Redbeds of Iceland - a High-Latitude Terrestrial Paleoclimate Monitor Driven by Chemical Weathering

    Science.gov (United States)

    Riishuus, M. S.; Bird, D. K.

    2012-12-01

    Chemical weathering of tephra and aeolian dust of basaltic composition produces clays and iron oxide/hydroxide minerals preserved in reddened layers referred to as redbeds, boles or paleosols. We propose that the extent of weathering of Neogene redbeds in Iceland and the isotopic composition of structurally bound water in associated weathering clay preserve records of high-latitude paleoclimatic and hydrologic conditions. In support we present whole-rock geochemistry and smectite D/H compositions of redbed horizons from Iceland for comparative analysis with global paleoclimate trends and local independent proxy data. Smectite δD values of 35 basaltic tephras in Iceland (~15-2 Ma) display a general decrease in δD compositions from -110 to -105 ‰ at ~15-13 Ma to -115 to -118 ‰ at ~3-2 Ma which correlates well with the global cooling trend from the Middle Miocene Climatic Optimum (17-15 Ma) to present day. Furthermore, the extent of weathering expressed by the Chemical Index of Weathering increases from 40-50 at 2-3 Ma to 80-90 at 15-16 Ma suggesting enhanced chemical weathering rates during the warmer climate conditions. The weathering extent of modern andosols in Iceland is temperature-dependant and allows construction of a paleo-climate proxy [1]. Application of this proxy suggests that mean annual temperatures (MATs) increased from ~0°C at ~2 Ma to ~9°C at 15-16 Ma in general agreement with independent local proxy data. The δD values of paleo meteoric waters in Iceland, estimated using a smectite-water fractionation factor and model MATs, decrease from -41 ‰ at 15-16 Ma (9°C) to -45 ‰ at 2 Ma (0°C). The paleo meteoric water compositions are increasingly enriched in deuterium relative to present day meteoric water in Iceland (δD ≤ -50 ‰). This is in agreement with global cooling since Middle Miocene toward ice-dominated conditions with greater equator-to-pole temperature contrasts, affecting the distillation process between ocean, atmosphere and

  11. Role of Lichens in Weathering and Soil—Forming Processes in Fildes Peninsula,Antarctic

    Institute of Scientific and Technical Information of China (English)

    CHENJIE; GONGZi-TONG

    1995-01-01

    Lichens play an unparalleledly vital role in weathering and soil-forming processes in Antarctic region,In this study some related chemical components and micromorphological analyses have been carried out on the samples of the weathered rocks and the lichens grown on them from Files Peninsula,Antarctic,The results indicatied that the major chemical components in the bioweathering surface layer of the sampled rocks have been obviously altered and the weathering potential in this layer has greatly decreased by and average range around 4.66 percent in 4 samples,In the weathering surface layer ferruginiztion of some minerals in varying degress was seen by means of microscopic examination through the thin section of the weathered rocks,and its products proved to be dominated by hematitie,limonite,goethite and free iron oxides Meanwhile,the study suggested that the dissolution and absorption of lichens by their secretion accelerated the process of calcitization of minerals in the bio-weathering suface layer,Eventually,the results also show that different species of lichens play different roles in weathering and soil-forming proesses.

  12. Constraints on continental crustal mass loss via chemical weathering using lithium and its isotopes

    OpenAIRE

    Liu, Xiao-ming; Rudnick, Roberta L.

    2011-01-01

    Chemical weathering, as well as physical erosion, changes the composition and shapes the surface of the continental crust. However, the amount of continental material that has been lost over Earth’s history due to chemical weathering is poorly constrained. Using a mass balance model for lithium inputs and outputs from the continental crust, we find that the mass of continental crust that has been lost due to chemical weathering is at least 15% of the original mass of the juvenile continental ...

  13. [Role of microscopic fungi in the process of weathering of pegmatite deposit rocks and minerals].

    Science.gov (United States)

    Avakian, Z A; Karavaiko, G I; Mel'nikova, E O; Krutsko, V S; Ostroushko, Iu I

    1981-01-01

    The object of this work was to study the effect of microscopic fungi isolated from the weathering zone of a pegmatite deposit on the transport of elements and the degradation of rocks and minerals. Regardless of the chemical composition of rocks and minerals, microscopic fungi accelerated the leaching of elements as compared to the purely chemical process. The extraction of Li, Si, Al and Fe under the action of microorganisms increased by factors of 1.4-1.7, 2.7-4.0, 5.0-8.7 and 4-18, respectively. In the case of chemical weathering, the extraction of elements occurred at a high rate only at the beginning; then the process either decelerated or stopped. The mechanism of action of microscopic fungi on rocks and minerals is discussed as well as the role of these microorganisms in the weathering of spodumene and the surrounding rocks, pegmatites an shales, which occurs in the zone of hypergenesis. PMID:7194415

  14. The role of chemical weathering in the neutralization of acid rain

    International Nuclear Information System (INIS)

    Chemical weathering of soils/minerals is an important process which controls the long-term neutralization of acid rain as well as the quality of surface water, ground water, and oceans. Few laboratory studies have been conducted to evaluate the response of real whole soils or soil fractions to acidification. In this research experiments were performed in a laboratory semi-continuous pH-stat reactor over the pH range 2.7 to 4.7 using Band C-horizon soil fractions from the Bear Brook Watershed, Maine, and in presence/absence of 1 to 20 mmol/L oxalate ligand in the bulk solution. Acid consumption rate and the corresponding release rates of sodium, calcium, magnesium, aluminum, iron, and silica were monitored in the laboratory reactor. Both H+-ion and oxalate promoted weathering rates were fractional order based on the concentration in bulk solution. The mixed kinetic model for the soils is: WRT = WRH + WRox = KH (H+)m + Kox [OX TD]p, where m and p are fractional orders. The hydrogen ion consumption rates were approximately equal to cation release rates on an equivalent basis for hydrogen ion promoted weathering situations where secondary precipitation was unlikely (pH < 4.7) as well as for weathering of C-horizon light fraction at pH 4.0 and oxalate concentration 1 and 5 mmol/L. The relative proportions of released species were in the neighborhood of stoichiometric ratios of bulk soil chemistry for weatherable minerals in Band C-horizon soil fractions. The experimental ratios of H/Si, Al/Si, Fe/Si, Ca/Si, Na/Si, and Mg/Si for linear weathering rates of Band C-horizon soil fractions were fairly constant in the presence and absence of oxalate ligand and strongly suggested that silica may be used as a tracer for primary mineral weathering assuming quartz is inert

  15. Weathering Processes Across Extreme Erosional Gradients: Do Landslides Matter?

    Science.gov (United States)

    Emberson, R.; Hovius, N.; Galy, A.; Marc, O.

    2015-12-01

    A process-based understanding of weathering in actively eroding mountain belts is vital to understand how linkages between erosion and weathering affect global biogeochemical cycles on a range of timescales. Here we present surface water chemistry data from Southern Taiwan that demonstrates the impact of variable erosive processes on weathering budgets on a large range of scales, from tens of metres to large catchments (>50km2). Southern Taiwan is an excellent example of a number of gradients in erosive processes, with relief and median slope increasing from the southernmost small hills to mountainous threshold-hillslopes with up to 2.5km of relief approximately 100km to the north. Furthermore, Typhoon Morakot (2009) triggered extremely extensive landsliding in some catchments within this zone, allowing distinctions to be drawn between average topographic characteristics of catchments and the erosive processes (i.e. mass wasting) at work therein. Landslides play an important role in localising weathering in deposits with high internal surface area and slow throughflow of fluids, creating sites of rapid weathering which can be a first order control on catchment solute budgets in watersheds where landslides deposits and scars exceed 2% of drained area. Variation in the detailed chemistry of landslide seepages - particularly the carbonate/silicate weathering balance - indicates that this process has a different impact on inorganic weathering-driven carbon cycling than slower erosive processes; a strong positive correlation between landslide-affected area and Ca2+:Si ratios on catchment scale suggests rapid erosion is not strongly coupled to CO2 drawdown. Rapid oxidation of sulphides - ubiquitous in many rapidly eroding mountain belts - within highly fragmented landslide deposits, and associated sulphuric-acid driven weathering, further complicates the effect landsliding has on the carbon cycle.

  16. Lasers in chemical processing

    International Nuclear Information System (INIS)

    The high cost of laser energy is the crucial issue in any potential laser-processing application. It is expensive relative to other forms of energy and to most bulk chemicals. We show those factors that have previously frustrated attempts to find commercially viable laser-induced processes for the production of materials. Having identified the general criteria to be satisfied by an economically successful laser process and shown how these imply the laser-system requirements, we present a status report on the uranium laser isotope separation (LIS) program at the Lawrence Livermore National Laboratory

  17. Constraints on the Global-scale Chemical Weathering State of Mars From TES Results Based on Spectral Analysis of Chemically Weathered Basalts

    Science.gov (United States)

    Michalski, J. R.; Kraft, M. D.; Sharp, T. G.; Christensen, P. R.

    2005-12-01

    On Earth, subaerially exposed basaltic rocks (from arid-to-tropical regions) develop weathering rinds and rock coatings that affect spectroscopic measurements of their natural surfaces. Similarly, basaltic rocks and basaltic soil particles on Mars may have rinds and coatings that are spectroscopically observable. Thermal emission spectroscopy, because it provides information about the composition and structure of silicate and non-silicate minerals and mineraloids, provides a useful perspective on the mineralogy of weathered surfaces; reconciliation of the emission spectral features of weathered surfaces with observations from other datasets is critical to interpretations of thermal emission spectral features of Mars. In this study, we investigate the thermal emission (6-25 μm) and visible/near-infrared (VNIR) (0.4-2.5 μm) spectroscopic features of fresh and weathered surfaces of rock samples from the Columbia River Basalt Group (CRBG). VNIR spectra of weathered rock surfaces are brighter and redder than fresh rock surfaces, but contain no evidence for neoformation of clay minerals within subaerially exposed, weathered surfaces. In contrast, thermal emission spectroscopy suggests an enrichment of clay minerals in weathered surfaces. Also, thermal emission spectroscopy indicates the presence of glass-like materials in many weathered surfaces, which likely correspond to amorphous weathering products present within fractures, as coatings on minerals, or as coatings on the rocks themselves. These results have important implications for interpretation of TES and THEMIS data of Mars, including: 1) glasses and clays detected on Mars from thermal infrared spectra may correspond to poorly crystalline weathering products within chemically weathered rock surfaces, 2) chemically weathered surfaces of basalts may appear oxidized but clay-poor to VNIR datasets, and 3) the differential chemical breakdown of primary phases can affect interpretations of the remaining primary rock

  18. Hillslope chemical weathering across Paraná, Brazil: a data mining-GIS hybrid approach

    Science.gov (United States)

    Iwashita, Fabio; Friedel, Michael J.; Filho, Carlos Roberto de Souza; Fraser, Stephen J.

    2011-01-01

    Self-organizing map (SOM) and geographic information system (GIS) models were used to investigate the nonlinear relationships associated with geochemical weathering processes at local (~100 km2) and regional (~50,000 km2) scales. The data set consisted of 1) 22 B-horizon soil variables: P, C, pH, Al, total acidity, Ca, Mg, K, total cation exchange capacity, sum of exchangeable bases, base saturation, Cu, Zn, Fe, B, S, Mn, gammaspectrometry (total count, potassium, thorium, and uranium) and magnetic susceptibility measures; and 2) six topographic variables: elevation, slope, aspect, hydrological accumulated flux, horizontal curvature and vertical curvature. It is characterized at 304 locations from a quasi-regular grid spaced about 24 km across the state of Paraná. This data base was split into two subsets: one for analysis and modeling (274 samples) and the other for validation (30 samples) purposes. The self-organizing map and clustering methods were used to identify and classify the relations among solid-phase chemical element concentrations and GIS derived topographic models. The correlation between elevation and k-means clusters related the relative position inside hydrologic macro basins, which was interpreted as an expression of the weathering process reaching a steady-state condition at the regional scale. Locally, the chemical element concentrations were related to the vertical curvature representing concave–convex hillslope features, where concave hillslopes with convergent flux tends to be a reducing environment and convex hillslopes with divergent flux, oxidizing environments. Stochastic cross validation demonstrated that the SOM produced unbiased classifications and quantified the relative amount of uncertainty in predictions. This work strengthens the hypothesis that, at B-horizon steady-state conditions, the terrain morphometry were linked with the soil geochemical weathering in a two-way dependent process: the topographic relief was a factor on

  19. Hydrological controls on Chemical weathering in the Jinsha River draining the southeastern Qinghai-Tibet Plateau

    Science.gov (United States)

    Zhong, Jun; Li, Siliang; Yue, Fujun; Ding, Hu

    2016-04-01

    The geochemistry of the riverine waters could provide an insight in understanding the surface processes, such as chemical weathering and carbon cycle. As the headwater of Chanjiang (Yangtze) River, Jinsha River flows on the southestern Qinhai-Tibet Plateau at high altitute (from 1000m to 4600m) above the major areas of human impact and carries important information on this erosive region. In spite of being impacted by monsoonal climate and with significant variations of discharge, the temporal variations of compositions of main ions and chemical weathering of Jinsha River are rarely documented. In this study, a systematic investigation on the seasonal and episodic water geochemistry (major ions and δ13CDIC) of the outlet of Jinsha River basin were carried out with the purpose of 1) characterizing temporal variations of aqueous geochemistry and its controlling factors, 2) quantifying rock weathering and associated CO2 consumption rates, and 3) exploring the impact of hydrological controls on chemical weathering of the Jinsha River Basin. The results show that the concentrations of Ca, Mg, HCO3 and NO3 are generally decreased during monsoon season, while that of Cl, Na, SO4, K are relative higher in monsoon season than in dry season, which may be mainly caused by hydrological condition, i.e., with increased runoff, more surficial evaporate dissolved water and salt lake water of the Basin flow into the river. Moreover, due to increased contribution of soil CO2and fast decomposition of organic matters, δ13CDIC in the high-flow period has more negative values than in low-flow period, and shows a negative relation with the concentration of DOC. An increasing of Ca concentrations was found with shift of the δ13CDIC values, positively, indicating the precipitation might be occured. Meanwhile, the dissolution of gypsum and anhydrite might enhance the calcium precipition. The forward model results show that the weathering rates of silicate and carbonate as well as that of

  20. Geophysical and Chemical Weathering Signatures Across the Deep Weathered-Unweathered Granite Boundary of the Calhoun Critical Zone Observatory

    Science.gov (United States)

    Richter, D., Jr.; Bacon, A. R.; Brantley, S. L.; Holbrook, W. S.

    2015-12-01

    To understand the relationship between geophysical measurements and chemical weathering at Earth's surface, we combine comprehensive chemical and physical analyses of a 70-m granite weathering profile in the Southern Piedmont in the southeastern United States. The research site is in the uplands of the Calhoun Critical Zone Observatory and is similar to many geomorphically stable, ancient, and highly-weathered Ultisol soils of the region. Surface and downhole geophysical analyses suggest significant physical changes to depths of about 40 m, where geophysical properties are consistent with competent and unweathered granite. At this depth, surface refraction velocities increase to >4.5 km/s; variations in downhole sonic velocities decrease by more than two-fold; and deviations in the downhole caliper log sharply decrease as well. Forty meters depth is also the depth of initiation of plagioclase feldspar weathering, as inferred from bulk geochemical measurement of the full 70-m deep core. Specifically, element-depth profiles, cast as mass transfer coefficient profiles using Ti and Zr as immobile elements, document inferred loss of plagioclase in the depth interval between 15 and 40-m depth. Plagioclase feldspar is the most abundant of the highly reactive minerals in the granite. Such a wide reaction front is characteristic of weathering granites. Some loss of K is observed at these depths but most K loss, as well as Mg loss, occurs at shallower depths. Nearby geophysical profiles and 3D stress models have been interpreted as showing that seismic velocities decrease at 40 m depth due to opening of fractures as rock is exhumed toward the surface. Given our interpretations of both the geochemical and geophysical data, we infer that the onset of chemical weathering of feldspar coincides with the opening of these fractures. The data highlight the ability of geochemistry and geophysics to complement each other and enrich our understanding of Earth's Critical Zone.

  1. An Unusual Process of Accelerated Weathering of a Marly Limestone

    Science.gov (United States)

    Ercoli, L.; Rizzo, G.; Algozzini, G.

    2003-04-01

    This work deals with a singular case of stone deterioration, which occurred during the restoration of the Cathedral of Cefalù. In particular, a significant process of stone decohesion started after a consolidation treatment on ashlars of the external face of the cloister portico. A study was carried out to characterize the stone and to investigate the deterioration process. Petrographical, chemical and physical analyses were performed on samples taken from the wall. The results indicate that the medieval monument was built using a Pliocene marly limestone, called "trubo", quarried from outcrops of the environs of Cefalù. The rock is soft and uniformely cemented. The carbonatic fraction of the rock is due to foraminifera shells; the rock also contains detritic quartz, feldspate and glauconite. The clay minerals, mainly illite and montmorillonite, are widespread in the rock in the form of thin layers. The use of such a stone in a building of relevant artistic value is definitely unusual. In fact, the "trubo" is a rock subjected to natural decay because of its mineralogical composition and fabric; as effect of natural weathering, in the outcrops the rock disaggregates uniformely, producing silt. In the cloister this effect was magnified by extreme environmental conditions (marine spray, severe excursions of both relative humidity and temperature). Furthermore, after soluble salts removing and subsequent consolidation with ethyl silicate, a significant acceleration of the decay process was observed, producing friable scales detach for a depth of about 3 cm into the ashlars. The stone appeared corroded and uneven. Experimental tests were performed in laboratory in order to evidence any origin of incompatibility between such stone composition and the treatments carried out, which on the other hand are the most generally adopted in restoration interventions.

  2. Mapping Glacial Weathering Processes with Thermal Infrared Remote Sensing: A Case Study at Robertson Glacier, Canada

    Science.gov (United States)

    Rutledge, A. M.; Christensen, P. R.; Shock, E.; Canovas, P. A., III

    2014-12-01

    Geologic weathering processes in cold environments, especially subglacial chemical processes acting on rock and sediment, are not well characterized due to the difficulty of accessing these environments. Glacial weathering of geologic materials contributes to the solute flux in meltwater and provides a potential source of energy to chemotrophic microbes, and is thus an important component to understand. In this study, we use Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data to map the extent of glacial weathering in the front range of the Canadian Rockies using remotely detected infrared spectra. We ground-truth our observations using laboratory infrared spectroscopy, x-ray diffraction, and geochemical analyses of field samples. The major goals of the project are to quantify weathering inputs to the glacial energy budget, and to link in situ sampling with remote sensing capabilities. Robertson Glacier, Alberta, Canada is an excellent field site for this technique as it is easily accessible and its retreating stage allows sampling of fresh subglacial and englacial sediments. Infrared imagery of the region was collected with the ASTER satellite instrument. At that same time, samples of glacially altered rock and sediments were collected on a downstream transect of the glacier and outwash plain. Infrared laboratory spectroscopy and x-ray diffraction were used to determine the composition and abundance of minerals present. Geochemical data were also collected at each location, and ice and water samples were analyzed for major and minor elements. Our initial conclusion is that the majority of the weathering seems to be occurring at the glacier-rock interface rather than in the outwash stream. Results from both laboratory and ASTER data indicate the presence of leached weathering rinds. A general trend of decreasing carbonate abundances with elevation (i.e. residence time in ice) is observed, which is consistent with increasing calcium ion

  3. The chemical weathering regime of Kärkevagge, arctic-alpine Sweden

    Science.gov (United States)

    Thorn, Colin E.; Darmody, Robert G.; Dixon, John C.; Schlyter, Peter

    2001-11-01

    Kärkevagge is a valley located in Swedish Lapland at approximately 68°N and represents an arctic-alpine landscape. It is a presently periglacial, glaciated trough incised into essentially horizontal metamorphic rocks, some of which are presumably pyrite-rich. A set of coordinated studies was undertaken to investigate the nature of chemical weathering and pedogenesis in the valley and upon the abutting ridges. August 1996 water quality measures reveal considerable spatial variation in solute totals with the highest Total Dissolved Solute abundances being correlated with high sulfate abundances. Ridge-crest soils exhibited poor horizonation, but more extensive development of secondary clay minerals developed in situ than was found in valley-flank and valley-bottom soils. Valley soils exhibited multiple thin horizons, many of which were buried, and are taken to reflect great paraglacial and periglacial instability. Favorable microenvironments in the valley permit significant development of Spodosols. Coarse debris along and across the valley bears both weathering rinds and rock coatings. Rock coatings in the valley include several types of iron films, sulfate crusts, carbonate skins, and heavy metal skins. Kärkevagge represents a mild arctic environment, which does not preclude substantial chemical weathering in locations where abundant pyrite-rich bedrock and water coincide. This weathering follows pathways which are eminently expectable given that weathering of the pyrite-rich rock permits generation of sulfuric acid which, in turn, weathers muscovite mica and calcite in local schists and marble, respectively. Zones of intense chemical weathering also generate clearly visible deposits of gypsum and iron sulfate deposits such as jarosite. Not all arctic and/or alpine environments are likely to be so active chemically, but the results from Kärkevagge clearly show that dismissal of chemical weathering in cold regions on the basis of presumed first principles is

  4. Chemical weathering on Mars - Thermodynamic stabilities of primary minerals /and their alteration products/ from mafic igneous rocks

    Science.gov (United States)

    Gooding, J. L.

    1978-01-01

    Chemical weathering on Mars is examined theoretically from the standpoint of thermodynamic equilibrium between primary rock-forming minerals and the atmospheric gases O2, H2O, and CO2. The primary minerals considered are those common to mafic igneous rocks and include olivine, pyroxene, plagioclase, magnetite, troilite, pyrrhotite, and apatite. The importance of kinetics and reaction mechanisms in controlling possible weathering processes on Mars is discussed within the limits of currently available data, and the possible influence of liquid water on Martian weathering processes is evaluated where appropriate. For gas-solid weathering of mafic igneous rocks at the Martian surface, it is concluded that upon attainment of thermodynamic equilibrium: (1) oxides and carbonates should dominate the mineral assemblage of weathering products; (2) hematite rather than goethite should be the stable mineral form of Fe (III); (3) FeSO4 or FeSO4.H2O could be the stable weathering product of iron sulfides in the absence of liquid water; and (4) kaolinite is apparently the only clay mineral that should be thermodynamically stable over all ranges of temperature and water-vapor abundance at the Martian surface.

  5. Chemical processing of lunar materials

    Science.gov (United States)

    Criswell, D. R.; Waldron, R. D.

    1979-01-01

    The paper highlights recent work on the general problem of processing lunar materials. The discussion covers lunar source materials, refined products, motivations for using lunar materials, and general considerations for a lunar or space processing plant. Attention is given to chemical processing through various techniques, including electrolysis of molten silicates, carbothermic/silicothermic reduction, carbo-chlorination process, NaOH basic-leach process, and HF acid-leach process. Several options for chemical processing of lunar materials are well within the state of the art of applied chemistry and chemical engineering to begin development based on the extensive knowledge of lunar materials.

  6. Structural control of weathering processes within exhumed granitoids: Compartmentalisation of geophysical properties by faults and fractures

    Science.gov (United States)

    Place, J.; Géraud, Y.; Diraison, M.; Herquel, G.; Edel, J.-B.; Bano, M.; Le Garzic, E.; Walter, B.

    2016-03-01

    In the latter stages of exhumation processes, rocks undergo weathering. Weathering halos have been described in the vicinity of structures such as faults, veins or dykes, with a lateral size gradually narrowing with depth, symmetrically around the structures. In this paper, we describe the geophysical characterisation of such alteration patterns on two granitoid outcrops of the Catalan Coastal Ranges (Spain), each of which is affected by one major fault, as well as minor faults and fractures. Seismic, electric and ground penetrating radar surveys were carried out to map the spatial distribution of P-wave velocity, electrical resistivity and to identify reflectors of electromagnetic waves. The analysis of this multi-method and complementary dataset revealed that, at shallow depth, geophysical properties of the materials are compartmentalised and asymmetric with respect to major and subsidiary faults affecting the rock mass. This compartmentalisation and asymmetry both tend to attenuate with depth, whereas the effect of weathering is more symmetric with respect to the major structure of the outcrops. We interpret such compartmentalisation as resulting from the role of hydraulic and mechanical boundaries played by subsidiary faults, which tend to govern both the chemical and physical alterations involved in weathering. Thus, the smoothly narrowing halo model is not always accurate, as weathering halos can be strongly asymmetrical and present highly irregular contours delimiting sharp contrasts of geophysical properties. These results should be considered when investigating and modelling fluid storage and transfer in top crystalline rock settings for groundwater applications, hydrocarbon or geothermal reservoirs, as well as mineral deposits.

  7. Van Allen Probes Science Gateway and Space Weather Data Processing

    Science.gov (United States)

    Romeo, G.; Barnes, R. J.; Weiss, M.; Fox, N. J.; Mauk, B.; Potter, M.; Kessel, R.

    2014-12-01

    The Van Allen Probes Science Gateway acts as a centralized interface to the instrument Science Operation Centers (SOCs), provides mission planning tools, and hosts a number of science related activities such as the mission bibliography. Most importantly, the Gateway acts as the primary site for processing and delivering the VAP Space Weather data to users. Over the past year, the web-site has been completely redesigned with the focus on easier navigation and improvements of the existing tools such as the orbit plotter, position calculator and magnetic footprint tool. In addition, a new data plotting facility has been added. Based on HTML5, which allows users to interactively plot Van Allen Probes summary and space weather data. The user can tailor the tool to display exactly the plot they wish to see and then share this with other users via either a URL or by QR code. Various types of plots can be created, including simple time series, data plotted as a function of orbital location, and time versus L-Shell. We discuss the new Van Allen Probes Science Gateway and the Space Weather Data Pipeline.

  8. Chemical weathering history of the southern Tajikistan loess and paleoclimate implications

    Institute of Scientific and Technical Information of China (English)

    DING; Feng(丁峰); DING; Zhongli(丁仲礼)

    2003-01-01

    Major chemical elements and Rb, Sr, Ba abundances were measured for loess samples from Chashmanigar loess-soil sequence in southern Tajikistan. And the degree of element loss and intensity of weathering of the samples were calculated. From these calculations we found that the paleosol horizons of the Chashmanigar section were chemically weathered to some extent and the weathering intensity of the soils is stronger than that of loess horizons, indicating that paleosols in southern Tajikistan were deposited in relatively warm and humid interglacial ages. In addition, the southern Tajikistan loess deposited before 0.9Ma BP was more intensely weathered than that deposited after 0.9Ma BP, which may imply the intensification of aridity in this area since 0.9Ma BP.

  9. Chemical weathering in Zhujiang River Drainage%珠江流域的化学侵蚀

    Institute of Scientific and Technical Information of China (English)

    高全洲; 沈承德; 孙彦敏; 易熙; 邢长平; 陶贞

    2001-01-01

    he chemical weathering processes on the continental carbonate and silicate minerals consume a large amount of carbon dioxide both from atmosphere and soil air. This gaseous substance, which is the dominating greenhouse gases in the atmosphere, was transformed into fluid substance and transported into the ocean by rivers in the form of bicarbonate ion. In this aspect, the weathering and transportation of bicarbonate ion in river system stand for an important linkage in the global carbon cycle. The range of global climate change in the geological history was weakened through this kind of negative feedback mechanism, i.e., the higher the atmospheric temperature is, the intense the chemical weathering process will be. However, an intense chemical weathering process will consume much greater amount of carbon dioxide, which can drop down the atmospheric temperature.   The Xijiang and Beijiang river drainage areas, which buildup most of the area of the Zhujiang (Pearl) river drainage, located in the typical sub tropical region in South China, are about 353 120 and 46 710 km2 in area, respectively. The discharge is about 230× 109 m3/a for Xijiang River, and 51× 109 m3/a for Beijiang River. The two drainage areas, characterized by the superposition temporarily of the high atmospheric temperature and plenty of precipitation, are the only areas of highest yield of biomass in mid low latitude zone in Northern Hemisphere. The carbonate rocks distribute widely in the two drainage basins. Red regolith crust and limestone red earth are the main soil forming material in those areas. The surficial geochemistry process taken place in the two drainage areas is intense due to the high degree of plant coverage, and due to the plenty of precipitation and a high atmospheric temperature. On the other hand, the mechanical erosion is also intense due to the precipitous topography, and due to high population density, which lead to a high ratio of cultivated area.

  10. Chemical Weathering of New Pyroclastic Deposits from Mt. Merapi (Java), Indonesia

    Energy Technology Data Exchange (ETDEWEB)

    Fiantis, Dian; Nelson, Malik; Van Ranst, Eric; Shamshudin, Josup; Qafoku, Nikolla

    2009-09-01

    Java Island, Indonesia with abundant amount of pyroclastic deposits is located in the very active and dynamic Pacific Ring of Fires. Studying the geochemical weathering indices of these pyroclastic deposits is important to get a clear picture about weathering profiles on deposits resulting from the eruption of Mt. Merapi. Immediately after the first phase of the eruption (March to June 2006), moist and leached pyroclastic deposits were collected. These pyroclastic deposits were found to be composed of volcanic glass, plagioclase feldspar in various proportions, orthopyroxene, clinopyroxene, olivine, amphibole, and titanomagnetite. Total elemental composition of the bulk samples (including trace elements and heavy metals) were determined by wet chemical methods and X-ray fluorescence (XRF) analyses. Weathering of the pyroclastic deposits was studied using various weathering indices. The Ruxton ratio, weathering index of Parker, Vought resudual index and chemical index of weathering of moist pyroclastic are lower than the leached sample but the alteration indices (chemical and plagioclase) are slightly higher in the moist compared to the leached pyroclastic deposits.

  11. Zeolite Formation and Weathering Processes in Dry Valleys of Antartica: Martian Analogs

    Science.gov (United States)

    Gibson, E. K., Jr.; Wentworth, S. J.; McKay, D. S.; Socki, R. A.

    2004-01-01

    Terrestrial weathering processes in cold-desert climates such as the Dry Valleys of Antarctica may provide an excellent analog to chemical weathering and diagenesis of soils on Mars. Detailed studies of soil development and the chemical and mineralogical alterations occurring within soil columns in Wright Valley, Antarctica show incredible complexity in the upper meter of soil. Previous workers noted the ice-free Dry Valleys are the best terrestrial approximations to contemporary Mars. Images returned from the Pathfinder and Spirit landers show similarities to surfaces observed within the Dry Valleys. Similarities to Mars that exist in these valleys are: mean temperatures always below freezing (-20 C), no rainfall, sparse snowfall-rapidly removed by sublimation, desiccating winds, diurnal freeze-thaw cycles (even during daylight hours), low humidity, oxidative environment, relatively high solar radiation and low magnetic fields . The Dry Valley soils contain irregular distributions and low abundances of soil microorganisms that are somewhat unusual on Earth. Physical processes-such as sand abrasion-are dominant mechanisms of rock weathering in Antarctica. However, chemical weathering is also an important process even in such extreme climates. For example, ionic migration occurs even in frozen soils along liquid films on individual soil particles. It has also been shown that water with liquid-like properties is present in soils at temperatures on the order of approx.-80 C and it has been observed that the percentage of oxidized iron increases with increasing soil age and enrichments in oxidized iron occurs toward the surface. The presence of evaporates is evident and appear similar to "evaporite sites" within the Pathfinder and Spirit sites. Evaporites indicate ionic migration and chemical activity even in the permanently frozen zone. The presence of evaporates indicates that chemical weathering of rocks and possibly soils has been active. Authogenic zeolites have

  12. Chemical weathering of basaltic lava-flow since 300 kyr ago (La Réunion Island ,France)

    Science.gov (United States)

    Claude, Christelle; Meunier, Jean-Dominique; Dussouillez, Philippe; Traoré, Daouda; Pelt, Eric; Chabaux, François; Hamelin, Bruno; Colin, Fabrice

    2015-04-01

    Spheroidal weathering (also named corestone-shell systems hereafter called CSC) is a common form of chemical weathering affecting many types of rocks. Here we combine mineralogical observations, geochemistry of major and trace elements to Sr isotopes and U-series as an attempt to constrain the rate of spheroidal weathering of a basaltic flow dated at 292 ±13 ka from Piton de la Fournaise volcano (Réunion Island). Three zones can be characterized : corestones, grey and red shells. Our results show that weathering is increasing from the core to the red shells and is characterized by a loss of alkali elements and Si while Fe, Al and Ti contents remain constant. Total chemical weathering rates, calculated over 292 ka, are two orders of magnitude lower than present-day estimations from streamwater solute fluxes. Our results show that Sr is exported on a time scale of 1 rather than 300 ka. The extrapolation of this behaviour to all mobile elements allows to recalculate a total chemical weathering rate of 270 t/km2/yr, in the range of the present day estimations. Zr and Th appear as the most immobile elements. Uranium, on the opposite, is shown to be depleted in the cores and the grey shells but enriched in the red shells, probably adsorbed on Fe oxydes and halloysite. A U-transport model is used to estimate the weathering age of samples from the core and the grey and red shells. The process of U remobilization occurs on a timescale of ca 290 ka, i.e. the deposition age of the lava flow. The calculated weathering ages increase from the core to the red shells. Weathering rates are 5.5 ± 0.7 m/Ma for the grey shells and 1.4 ± 0.2 m/Ma for the red shells, with an average value of 2.9 ± 0.3 m/Ma. Finally, this result, compared with denudation rates of 3.5 ± 1.7 m/Ma estimated in the same area strenghthens our conclusion regarding a stable, steady state, geomorphological evolution of the site.

  13. Space-weathering processes and products on volatile-rich asteroids

    Science.gov (United States)

    Britt, D.; Schelling, P.; Consolmagno, G.; Bradley, T.

    2014-07-01

    Space weathering is a generic term for the effects on atmosphereless solid bodies in the solar system from a range of processes associated with direct exposure to the space environment. These include impact processes (shock, vaporization, fragmentation, heating, melting, and ejecta formation), radiation damage (from galactic and solar cosmic rays), solar-wind effects (irradiation, ion implantation, and sputtering), and the chemical reactions driven by these processes. The classic example of space weathering is the formation of the lunar spectral red slope associated with the production of nanophase Fe (npFe0) in the dusty lunar regolith (C.R. Chapman, 2004, Annual Review of Earth & Planet. Sci. 32, C.M. Pieters, 2000, MAPS 35). Similar npFe0 has been recovered from asteroid (25143) Itokawa and some asteroid classes do exhibit modest spectral red slopes (T. Noguchi, 2011, Science 333). Space weathering can be thought of as driven by a combination of the chemical environment of space (hard vacuum, low oxygen fugacity, solar-wind implantation of hydrogen) along with thermal energy supplied by micrometeorite impacts. The forward modeling of space weathering as thermodynamically-driven decomposition of common rock-forming minerals suggests the production of a range of daughter products: (1) The silicate products typically lose oxygen, other volatile elements (i.e., sulfur and sodium), and metallic cations, producing minerals that are typically more disordered and less optically active than the original parent materials. (2) The decomposed metallic cations form in nano-sized blebs including npFe0, on the surfaces or in condensing rims of mineral grains. This creates a powerful optical component as seen in the lunar red slope. Surfaces with exposed npFe0 are an ideal environment for catalyzing further reactions. (3) The liberated volatile elements and gases (O, S, Na) may form an observable exosphere (e.g., Moon and Mercury) and can either escape from the body or

  14. Improving aerosol interaction with clouds and precipitation in a regional chemical weather modeling system

    Directory of Open Access Journals (Sweden)

    C. Zhou

    2015-06-01

    Full Text Available A comprehensive aerosol–cloud–precipitation interaction (ACI scheme has been developed under CMA chemical weather modeling system GRAPES/CUACE. Calculated by a sectional aerosol activation scheme based on the information of size and mass from CUACE and the thermal-dynamic and humid states from the weather model GRAPES at each time step, the cloud condensation nuclei (CCN is fed online interactively into a two-moment cloud scheme (WDM6 and a convective parameterization to drive the cloud physics and precipitation formation processes. The modeling system has been applied to study the ACI for January 2013 when several persistent haze-fog events and eight precipitation events occurred. The results show that interactive aerosols with the WDM6 in GRAPES/CUACE obviously increase the total cloud water, liquid water content and cloud droplet number concentrations while decrease the mean diameter of cloud droplets with varying magnitudes of the changes in each case and region. These interactive micro-physical properties of clouds improve the calculation of their collection growth rates in some regions and hence the precipitation rate and distributions in the model, showing 24 to 48% enhancements of TS scoring for 6 h precipitation in almost all regions. The interactive aerosols with the WDM6 also reduce the regional mean bias of temperature by 3 °C during certain precipitation events, but the monthly means bias is only reduced by about 0.3 °C.

  15. Chemical Weathering Across a Climate by Time Matrix in the Hawaiian Islands

    Science.gov (United States)

    Porder, S.; Hilley, G. E.; Chadwick, O. A.

    2006-12-01

    We determined the total mass loss and rate of chemical weathering for three, minimally eroded, lava flows (~ 10, 170, and 350 ky old) on the Island of Hawai'i. Using a backhoe, we sampled the entire weathering zone in 7-14 locations on each flow, and calculated mass loss of each major element by comparison to an immobile element (niobium). Each flow crosses a precipitation gradient that ranges from ~ 600 to ~ 2,500 mm yr -1, so we were able to assess the relative influence of climate and substrate age on the chemical depletion of the parent material. Time-averaged mass loss rates were highest on the youngest flow under the wettest climatic conditions (55 t km -2 yr -1), and decreased almost twenty fold on the older flows under similar conditions. There was a precipitation threshold below which mass loss was relatively small, and above which mass loss was substantial but insensitive to increased rainfall. This threshold was dependent on parent material age, ranging from 1650 mm yr -1 on the youngest flow to 1000 mm yr ^{- 1} on the oldest. Rainfall had a smaller effect than flow age on weathering rates, which increased by a factor of <5 with increased rainfall. Every site exhibited mass loss rates within the range measured in granitic catchments, despite the higher reactivity of basalt than granite. Thus these data underscore the importance of physical weathering in producing chemically weatherable substrate. Finally, the soils on each of these basaltic flows contain quartz-rich dust blown predominantly from Asian deserts, and we calculated the total mass of dust added to each weathering zone during its development. Surprisingly, even though Hawai'i is one of the least dusty places in the northern hemisphere, dust inputs equaled up to 45% of the total mass loss from the weathering zone at some sites, highlighting the potential importance of dust as a component of observed weathering fluxes from catchments worldwide.

  16. Composition, origin and weathering process of surface sediment in Kumtagh Desert, Northwest China

    Institute of Scientific and Technical Information of China (English)

    XU Zhiwei; LU Huayu; ZHAO Cunfa; WANG Xianyan; SU Zhizhua; WANG Zhenting; LIU Hongyi; WANG Lixin; LU Qi

    2011-01-01

    Kumtagh Desert is one of the eight biggest deserts in China,but poorly investigated before our interdisciplinary study because of the difficulty of access.In this paper,33 representative surface sediment samples were collected from the Kumtagh Desert and analyzed in the laboratory to obtain heavy mineral components and geochemical element contents.Results show that various kinds of heavy minerals are present in these samples,with high levels of epidote and hornblende.Si and AI take up a large part of chemical composition.Compared with the average composition of geochemical elements of the upper continental crust (UCC),except Si and Ca,all elements are depleted to a certain degree; Fe,Mg,Ca,P,Ti and Mn have high correlation coefficients in their contents.The mineral and geochemical composition of the Kumtagh Desert sediments have a similarity with that of rocks of Altyn Tagh Mountains,and the surface sediments of the alluvial/diluvial fans around the Altyn Tagh Mountains and that of the Taklamakan Desert,indicating that one major source of the Kumtagh Desert sediments is located in the Altyn Tagh Mountains.Alluvial deposits and lake sediments in Aqik valley and lower reaches of Shule River are prone to be eroded and transported by the strong northeasterly wind into the Kumtagh Desert,forming another source of the desert deposits.An A-CN-K ternary diagram shows that a weak degree chemical weathering by the loss of Na and K occurred in these sediments,whereas A-CNK-FM temary diagram suggests that Fe and Mg have undergone a significant chemical differentiation.Physical weathering processes cause easy erosion and enrichment in fine particles for mafic minerals,thus coarse desert sand particles can be relatively depleted in Fe and Mg.The mineral and geochemical composition of sediments in arid regions experiencing less chemical weathering are mostly affected by physical weathering.

  17. Comparison of different representations of physical erosion on modeling chemical weathering in landslide-dominated region

    Science.gov (United States)

    Chen, Pei-Hao; Huang, -Chuan, Jr.; Teng, Tse-Yang; Shih, Yu-Ting; Lee, Tsung-Yu

    2016-04-01

    Chemical weathering, characterized by CO2 consumption, attracts much attention, particularly in landslide-dominated regions where the physical erosion rate (PER) may enhance the chemical weathering rate (CWR) which influences the stability of hillslope and nutrient supply of ecosystem. Recently, a great debate is on the coupling or decoupling with CWR and PER in high erosion area, particularly in the landslide-dominated region. However, the representations of PER either by sediment yield (West et al., 2005) or estimated by landslide distribution (Gabet, 2007) in such regions is rarely evaluated and discussed. Hence, we combined these two models on 29 catchments in Taiwan, famous for rapid erosion and weathering, to clarify how representations of PER affected estimation of chemical weathering in landslide-dominated regions. The results showed that in the sediment yield-based model, the coupling between CWR and PER in terms of power function (α, from CWR=PERα) were 0.09, 0.26, 0.22 for silicate weathering (CWRsil), carbonate weathering (CWRcarb), total chemical weathering (CWRtot), respectively. The R2 values were 0.48, 0.49, 0.57 for CWRsil, CWRcarb and CWRtot, respectively. Meanwhile, in the landslide-based model, α of CWRsil, CWRcarb and CWRtot were 0.78, 0.79, 0.79, respectively. The R2 values were 0.41, 0.58, 0.67, respectively. In sum, both model could perform the linkage between CWR and PER satisfactorily. The sediment yield-based model revealed CWR might be strongly kinetically limited. Besides, despite of lower performance than the landslide-based model, it distinguished relationships between different CWR(CWRsil, CWRcarb, CWRtot) and PER, but simulations of the landslide-based model were reversed. The α of the landslide-based model is significantly higher than previous studies. It implies that on perspective of landslides, PER may enhance CWR and matches with current researches.

  18. Historical Weathering Based on Chemical Analyses of Two Spodosols in Southern Sweden

    International Nuclear Information System (INIS)

    Chemical weathering losses were calculated for two conifer stands in relation to ongoing studies on liming effects and ash amendments on chemical status, soil solution chemistry and soil genesis. Weathering losses were based on elemental depletion trends in soil profiles since deglaciation and exposure to the weathering environment. Gradients in total geochemical composition were assumed to reflect alteration over time. Study sites were Horroed and Hassloev in southern Sweden. Both Horroed and Hassloev sites are located on sandy loamy Weichselian till at an altitude of 85 and 190 m a.s.l., respectively. Aliquots from volume determined samples from a number of soil levels were fused with lithium metaborate, dissolved in HNO3, and analysed by ICP - AES. Results indicated highest cumulative weathering losses at Hassloev. The weathering losses for the elements are in the following order:Si > Al > K > Na > Ca > MgTotal annual losses for Ca+Mg+K+Na, expressed in mmolc m-2 yr-1, amounted to c. 28 and 58 at Horroed and Hassloev, respectively. Variations between study sites could not be explained by differences in bulk density, geochemistry or mineralogy. The accumulated weathering losses since deglaciation were larger in the uppermost 15 cm than in deeper B horizons for most elements studied

  19. Predictions of Chemical Weather in Asia: The EU Panda Project

    Science.gov (United States)

    Brasseur, G. P.; Petersen, A. K.; Wang, X.; Granier, C.; Bouarar, I.

    2014-12-01

    Air quality has become a pressing problem in Asia and specifically in China due to rapid economic development (i.e., rapidly expanding motor vehicle fleets, growing industrial and power generation activities, domestic and biomass burning). In spite of efforts to reduce chemical emissions, high levels of particle matter and ozone are observed and lead to severe health problems with a large number of premature deaths. To support efforts to reduce air pollution, the European Union is supporting the PANDA project whose objective is to use space and surface observations of chemical species as well as advanced meteorological and chemical models to analyze and predict air quality in China. The Project involves 7 European and 7 Chinese groups. The paper will describe the objectives of the project and present some first accomplishments. The project focuses on the improvement of methods for monitoring air quality from combined space and in-situ observations, the development of a comprehensive prediction system that makes use of these observations, the elaboration of indicators for air quality in support of policies, and the development of toolboxes for the dissemination of information.

  20. Chemical Sensing for Buried Landmines - Fundamental Processes Influencing Trace Chemical Detection

    Energy Technology Data Exchange (ETDEWEB)

    PHELAN, JAMES M.

    2002-05-01

    Mine detection dogs have a demonstrated capability to locate hidden objects by trace chemical detection. Because of this capability, demining activities frequently employ mine detection dogs to locate individual buried landmines or for area reduction. The conditions appropriate for use of mine detection dogs are only beginning to emerge through diligent research that combines dog selection/training, the environmental conditions that impact landmine signature chemical vapors, and vapor sensing performance capability and reliability. This report seeks to address the fundamental soil-chemical interactions, driven by local weather history, that influence the availability of chemical for trace chemical detection. The processes evaluated include: landmine chemical emissions to the soil, chemical distribution in soils, chemical degradation in soils, and weather and chemical transport in soils. Simulation modeling is presented as a method to evaluate the complex interdependencies among these various processes and to establish conditions appropriate for trace chemical detection. Results from chemical analyses on soil samples obtained adjacent to landmines are presented and demonstrate the ultra-trace nature of these residues. Lastly, initial measurements of the vapor sensing performance of mine detection dogs demonstrates the extreme sensitivity of dogs in sensing landmine signature chemicals; however, reliability at these ultra-trace vapor concentrations still needs to be determined. Through this compilation, additional work is suggested that will fill in data gaps to improve the utility of trace chemical detection.

  1. Influence of chemical weathering on the composition of the continental crust: Insights from Li and Nd isotopes in bauxite profiles developed on Columbia River Basalts

    Science.gov (United States)

    Liu, Xiao-Ming; Rudnick, Roberta L.; McDonough, William F.; Cummings, Michael L.

    2013-08-01

    Mineralogical, chemical, and Li and Nd isotopic compositions of two drill cores (8-9 m deep) through bauxites developed on the Miocene Columbia River Basalts document the changes associated with basalt weathering, provide insights into the processes involved, and allow us to examine the overall influence of chemical weathering on juvenile (basaltic) crust. Gibbsite, hematite, ±kaolinite, halloysite, goethite, and maghemite are the weathering products in the bauxites. Quartz is observed near the tops of the cores and its abundance decreases progressively with depth; no quartz is observed below five meters depth in either core. Most major and trace elements, including "mobile" and some "immobile" elements are severely depleted in the bauxites. Niobium is less mobile relative to the rare earth elements, thus chemical weathering attenuates the negative Nb anomaly in the continental crust. Li and Nd are strongly depleted relative to fresh basalt, and both increase systematically towards the surface in the quartz-bearing samples while δ7Li and ɛNd values decrease systematically towards the surface in these same samples. Both Li and Nd were likely lost from the bauxites through leaching. The systematic enrichment of Li, Nd, and quartz, as well as the less radiogenic Nd isotopic composition at the tops of both profiles reflects 20-60 wt.% addition of an eolian component to the soils. The eolian dust is unlikely to have experienced significant post-depositional weathering due to the relatively high Li contents near the tops of the profiles, and, therefore, the low δ7Li and ɛNd values suggest that the dust came from an old, weathered region of the continent. Our results demonstrate that lithium isotopes are sensitive tracers of chemical weathering, particularly in extreme weathering settings, and support the hypothesis that chemical weathering influences the mass and composition of the continental crust.

  2. Chemical weathering and associated carbon-dioxide consumption in a tropical river basin (Swarna River), Southwestern India

    Science.gov (United States)

    Muguli, T.; Gurumurthy, G. P.; Balakrishna, K.; Audry, S.; Riotte, J.; Braun, J.; Chadaga, M.; Shankar HN, U.

    2013-12-01

    Chemical weathering in river basins forms the key process to study the global climate change on a long term scale due to its association with the carbon sequestration. Water samples from a west flowing tropical river (Swarna River) of Southern India were collected for a period of two years to study the chemical weathering process and to quantify the weathering and associated carbon-dioxide consumption rates in the river basin. In addition, the major ion chemistry of Swarna River is studied for the first time on a spatial and temporal (monthly) scale to decipher the factors (lithology, precipitation/ discharge, temperature, slope and physical weathering) controlling the chemical weathering process. Swarna River originates in Western Ghats at an altitude of 1100 m above mean sea level and flows westwards draining Peninsular Gneiss and Dharwar Schist to join the Arabian Sea near Udupi. The river basin receives annual rainfall of 4500 mm and experiences warm climate with average temperature of 30°C. Major ion composition and radiogenic strontium isotopic composition measured in the Swarna river water reflects the influence of silicate rocks in the basin. The river water chemistry is found to be least affected by anthropogenic impact; however, the effect of evaporation is observed on few samples during the peak dry season. The atmospheric inputs and carbonate contributions to the river water are corrected to estimate the silicate weathering rate (SWR) and the associated carbon-dioxide consumption rate (CCR) using local rainwater and bed rock composition respectively. The SWR and CCR in the Swarna river basin are estimated to be 46 tons/km2/yr and 4.4 x 10^5 mol/km2/yr respectively. This estimation is observed to be relatively higher than the recently reported SWR and CCR in the adjacent larger Nethravati river basin (Gurumurthy et al., 2012). The increased rate could be attributed to the relatively higher precipitation in the Swarna river basin than the lithological

  3. COST ES0602: towards a European network on chemical weather forecasting and information systems

    Directory of Open Access Journals (Sweden)

    J. Kukkonen

    2009-04-01

    Full Text Available The COST ES0602 action provides a forum for benchmarking approaches and practices in data exchange and multi-model capabilities for chemical weather forecasting and near real-time information services in Europe. The action includes approximately 30 participants from 19 countries, and its duration is from 2007 to 2011 (http://www.chemicalweather.eu/. Major efforts have been dedicated in other actions and projects to the development of infrastructures for data flow. We have therefore aimed for collaboration with ongoing actions towards developing near real-time exchange of input data for air quality forecasting. We have collected information on the operational air quality forecasting models on a regional and continental scale in a structured form, and inter-compared and evaluated the physical and chemical structure of these models. We have also constructed a European chemical weather forecasting portal that includes links to most of the available chemical weather forecasting systems in Europe. The collaboration also includes the examination of the case studies that have been organized within COST-728, in order to inter-compare and evaluate the models against experimental data. We have also constructed an operational model forecasting ensemble. Data from a representative set of regional background stations have been selected, and the operational forecasts for this set of sites will be inter-compared and evaluated. The Action has investigated, analysed and reviewed existing chemical weather information systems and services, and will provide recommendations on best practices concerning the presentation and dissemination of chemical weather information towards the public and decision makers.

  4. A review of operational, regional-scale, chemical weather forecasting models in Europe

    Czech Academy of Sciences Publication Activity Database

    Kukkonen, J.; Olsson, T.; Schultz, D.M.; Baklanov, A.; Klein, T.; Miranda, A.I.; Monteiro, A.; Hirtl, M.; Tarvainen, V.; Boy, M.; Peuch, V.H.; PoupKou, A.; Kioutsioukis, I.; Finardi, S.; Sofiev, M.; Sokhi, R.; Lehtinen, K.E.J.; Karatzas, K.; San José, R.; Astitha, M.; Kallos, G.; Schaap, M.; Reimer, E.; Jakobs, H.; Eben, Kryštof

    2012-01-01

    Roč. 12, - (2012), s. 1-87. ISSN 1680-7316 Institutional research plan: CEZ:AV0Z10300504 Keywords : chemical weather * numerical models * operational forecasting * air Subject RIV: DG - Athmosphere Sciences, Meteorology Impact factor: 5.510, year: 2012

  5. Evolution of porosity and diffusivity associated with chemical weathering of a basalt clast

    International Nuclear Information System (INIS)

    Weathering of rocks as a result of exposure to water and the atmosphere can cause significant changes in their chemistry and porosity. In low-porosity rocks, such as basalts, changes in porosity, resulting from chemical weathering, are likely to modify the rock's effective diffusivity and permeability, affecting the rate of solute transport and thus potentially the rate of overall weathering to the extent that transport is the rate limiting step. Changes in total porosity as a result of mineral dissolution and precipitation have typically been used to calculate effective diffusion coefficients through Archie's law for reactive transport simulations of chemical weathering, but this approach fails to account for unconnected porosity that does not contribute to transport. In this study, we combine synchrotron X-ray microcomputed tomography (μCT) and laboratory and numerical diffusion experiments to examine changes in both total and effective porosity and effective diffusion coefficients across a weathering interface in a weathered basalt clast from Costa Rica. The μCT data indicate that below a critical value of ∼9%, the porosity is largely unconnected in the basalt clast. The μCT data were further used to construct a numerical pore network model to determine upscaled, effective diffusivities as a function of total porosity (ranging from 3 to 30%) for comparison with diffusivities determined in laboratory tracer experiments. By using effective porosity as the scaling parameter and accounting for critical porosity, a model is developed that accurately predicts continuum-scale effective diffusivities across the weathering interface of the basalt clast.

  6. Evolution of porosity and diffusivity associated with chemical weathering of a basalt clast

    Energy Technology Data Exchange (ETDEWEB)

    Navarre-Sitchler, A.; Steefel, C.I.; Yang, L.; Tomutsa, L.; Brantley, S.L.

    2009-02-15

    Weathering of rocks as a result of exposure to water and the atmosphere can cause significant changes in their chemistry and porosity. In low-porosity rocks, such as basalts, changes in porosity, resulting from chemical weathering, are likely to modify the rock's effective diffusivity and permeability, affecting the rate of solute transport and thus potentially the rate of overall weathering to the extent that transport is the rate limiting step. Changes in total porosity as a result of mineral dissolution and precipitation have typically been used to calculate effective diffusion coefficients through Archie's law for reactive transport simulations of chemical weathering, but this approach fails to account for unconnected porosity that does not contribute to transport. In this study, we combine synchrotron X-ray microcomputed tomography ({mu}CT) and laboratory and numerical diffusion experiments to examine changes in both total and effective porosity and effective diffusion coefficients across a weathering interface in a weathered basalt clast from Costa Rica. The {mu}CT data indicate that below a critical value of {approx}9%, the porosity is largely unconnected in the basalt clast. The {mu}CT data were further used to construct a numerical pore network model to determine upscaled, effective diffusivities as a function of total porosity (ranging from 3 to 30%) for comparison with diffusivities determined in laboratory tracer experiments. By using effective porosity as the scaling parameter and accounting for critical porosity, a model is developed that accurately predicts continuum-scale effective diffusivities across the weathering interface of the basalt clast.

  7. wradlib - an Open Source Library for Weather Radar Data Processing

    Science.gov (United States)

    Pfaff, Thomas; Heistermann, Maik; Jacobi, Stephan

    2014-05-01

    Even though weather radar holds great promise for the hydrological sciences, offering precipitation estimates with unrivaled spatial and temporal resolution, there are still problems impeding its widespread use, among which are: almost every radar data set comes with a different data format with public reading software being available only rarely. standard products as issued by the meteorological services often do not serve the needs of original research, having either too many or too few corrections applied. Especially when new correction methods are to be developed, researchers are often forced to start from scratch having to implement many corrections in addition to those they are actually interested in. many algorithms published in the literature cannot be recreated using the corresponding article only. Public codes, providing insight into the actual implementation and how an approach deals with possible exceptions are rare. the radial scanning setup of weather radar measurements produces additional challenges, when it comes to visualization or georeferencing of this type of data. Based on these experiences, and in the hope to spare others at least some of these tedious tasks, wradlib offers the results of the author's own efforts and a growing number of community-supplied methods. wradlib is designed as a Python library of functions and classes to assist users in their analysis of weather radar data. It provides solutions for all tasks along a typical processing chain leading from raw reflectivity data to corrected, georeferenced and possibly gauge adjusted quantitative precipitation estimates. There are modules for data input/output, data transformation including Z/R transformation, clutter identification, attenuation correction, dual polarization and differential phase processing, interpolation, georeferencing, compositing, gauge adjustment, verification and visualization. The interpreted nature of the Python programming language makes wradlib an ideal tool

  8. Changes in the chemical composition of the light crude by short-term weathering

    International Nuclear Information System (INIS)

    In the event of an oil spill, it is important to unambiguously identify the oil and link it to the known source in order to determine environmental impact and legal liability. The fate and behaviour of spilled oil depends on several physical, chemical and biological factors such as evaporation, dissolution, microbial degradation and photooxidation. The chemical composition of the spilled oil changes with weathering. The changes can have a significant effect on the oil's toxicity and can add to the difficulty of identifying spilled oil. This paper presents the results of changes in chemical composition of light crude oil by weathering under natural environmental conditions. Oil samples were analyzed on a gas chromatograph equipped with a mass selective detector. Light crude oil was obtained from the oil cabin of a tanker which spilled oil near the Dalian Sea near China in April 2005. It was shown that the saturated hydrocarbons of light crude oil distribute between n-C8 and n-C23. The most abundant n-alkanes are found in the n-C10 to n-C16. The main chemical compositions of the light crude oil are the n-alkanes and the isoprenoids. The aromatic compounds are subordinate chemical compositions of the light crude oil. A simulated weathering experiment showed that less than n-C12 of the n-alkanes, toluene, 1,3-dimethyl benzene is lost after 1 day of weathering. The n-C13, n-C14, naphthalene and 2-methyl-naphthalene are lost on the fifth day of weathering. N-C15 alkane composition indicates some weatherproof capability. The ratios of n-C17/pristine and n-C18/phytane were unchanged and useful in identifying the source of the light crude oil during the first 8-day weathering period. By the twenty-first day of weathering, the chemical composition underwent extreme alteration, and the source of the pollution could not be determined by the ratios of pristine/phytane. 12 refs., 3 tabs., 7 figs

  9. Improving aerosol interaction with clouds and precipitation in a regional chemical weather modeling system

    Science.gov (United States)

    Zhou, C.; Zhang, X.; Gong, S.; Wang, Y.; Xue, M.

    2016-01-01

    A comprehensive aerosol-cloud-precipitation interaction (ACI) scheme has been developed under a China Meteorological Administration (CMA) chemical weather modeling system, GRAPES/CUACE (Global/Regional Assimilation and PrEdiction System, CMA Unified Atmospheric Chemistry Environment). Calculated by a sectional aerosol activation scheme based on the information of size and mass from CUACE and the thermal-dynamic and humid states from the weather model GRAPES at each time step, the cloud condensation nuclei (CCN) are interactively fed online into a two-moment cloud scheme (WRF Double-Moment 6-class scheme - WDM6) and a convective parameterization to drive cloud physics and precipitation formation processes. The modeling system has been applied to study the ACI for January 2013 when several persistent haze-fog events and eight precipitation events occurred.The results show that aerosols that interact with the WDM6 in GRAPES/CUACE obviously increase the total cloud water, liquid water content, and cloud droplet number concentrations, while decreasing the mean diameters of cloud droplets with varying magnitudes of the changes in each case and region. These interactive microphysical properties of clouds improve the calculation of their collection growth rates in some regions and hence the precipitation rate and distributions in the model, showing 24 to 48 % enhancements of threat score for 6 h precipitation in almost all regions. The aerosols that interact with the WDM6 also reduce the regional mean bias of temperature by 3 °C during certain precipitation events, but the monthly means bias is only reduced by about 0.3 °C.

  10. Water geochemistry of the Chaohu Lake Basin rivers, China: Chemical weathering and anthropogenic inputs

    International Nuclear Information System (INIS)

    Highlights: → Chaohu Lake is one of the five largest freshwater lakes in China. → Eutrophication has become the most serious problems since the 1990s. → Chemical and Sr isotopic compositions were determined to quantify the contributions of different sources to the dissolved load. - Abstract: As one of the five largest freshwater lakes in China, the Chaohu Lake is polluted by many kinds of pollutants. Chemical and Sr isotopic compositions of river waters in the Zhegao River sub-catchment have been determined with the main purpose of understanding the contribution of chemical weathering and anthropogenic inputs to solutes. The major ion compositions of the river waters are characterized by the dominance of Ca2+ and HCO3-, followed by Mg2+ and SO42-. The chemical and Sr isotopic analyses indicate that three major reservoirs (carbonate, silicate and human activities) contribute to the dissolved load. The calculated results show that the dissolved load is dominated by carbonate weathering. The contribution of the anthropogenic inputs is estimated to be from 1.64% to 31.8%, with an average of 15.6%, demonstrating the strong impacts of human activities on water chemistry. The total chemical denudation flux of the Zhegao sub-catchment is about 127.7 ton km-2 a-1, with carbonate and silicate weathering rates of 97.5 ton km-2 a-1 and 30.2 ton km-2 a-1, respectively.

  11. Late Cenozoic Chemical Weathering and Environmental Changes Recorded in the Co Ngoin Sediments, Central Qinghai-Tibet Plateau

    Institute of Scientific and Technical Information of China (English)

    CHEN Shiyue; JIN Zhangdong; WANG Sumin; SHEN Ji

    2005-01-01

    A series of faulted inland basins were developed in the central Qinghai-Tibet Plateau, among which the Co Ngoin Basin containing thick lacustrine sediments is located in the peripheral area of the Indian monsoon. In this paper, we present the weathering history and paleoclimatic changes in the last 2.8 Ma based on studies of high-resolution temporal distributions of Sr, Rb and Zr concentrations, Rb/Sr and Zr/Rb ratios and δ 13C and TOC for the Co Ngoin sediments, in combination with the sediment properties, grain size distribution and clay mineralogy. The sedimentary records indicate three environmental stages in the last 2.8 Ma. At the core depth of 197-170 m (about 2.8-2.5 Ma), low-intensity chemical weathering in the Co Ngoin catchment was experienced under warm-dry to cool-wet climate conditions with relatively low Sr concentration and high Rb/Sr and Zr/Rb ratios. The sudden occurrence of both subalpine coniferous forest and coarse sand and gravel sediments in the Co Ngoin core reflects a strong tectonic uplift. The high Sr concentrations and low Rb/Sr and Zr/Rb ratios reflect a relatively strong chemical weathering between 2.5 Ma and 0.8 Ma (at the core depth of 170-38.5m) under a temperate/cool and wet climate, characterized by mud and silt with fine sand, probably indicating a stable process of denudation and planation of the plateau. Above the depth of 38.5 m (about 0.8-0 Ma), the coarsening of sediments indicates a strong tectonic uplift and a relatively low intensity of chemical weathering as supported by the record of sediments having relatively low Sr concentrations and high Rb/Sr and Zr/Rb ratios. Since then, the plateau has taken the shape of the modern topographic pattern above 4000 m a.s.1.

  12. Changes in the chemical components of light crude oil during simulated short term weathering

    Science.gov (United States)

    Ma, Qimin; Luo, Xia; Yu, Zhigang

    2007-07-01

    To unambiguously identify spilled oils and to link them to the known sources are extremely important in settling questions of environmental impact and legal liability. The fate and behavior of spilled oils in the environment depend on a number of physicochemical and biological factors. This paper presents the results regarding changes in chemical composition of light crude oil during simulated short-term weathering based on natural environmental conditions. The results show that the saturated hydrocarbons of the light crude oil mainly distribute between n-C8 and n-C23 and the most abundant n-alkanes are found in the n-C10 to n-C16. The main chemical components of the light crude oil are n-alkanes and isoprenoids. The aromatic compounds are subordinate chemical components. Under the conditions of the weathering simulation experiment, n-alkanes less than n-C12, toluene and 1,3-dimethyl benzene are lost after 1 d weathering, the n-C13, n-C14, naphthalene and 2-methyl-naphthalene are lost on the fifth day of weathering, and n-C15 alkane components show certain weatherproof capability. The ratios n-C17/pristane and n-C18/phytane are unaltered and can be used to identify the source of the light crude oil during the first 8 d of weathering. After 21 d, the ratio pristine/phytane can not provide much information on the source of the spilled light crude oil. Triterpanes (m/z 191) as biomarker compounds of light crude oil are more valuable.

  13. Interface-coupled dissolution-precipitation processes during acidic weathering of multicomponent minerals

    Science.gov (United States)

    Ruiz-Agudo, Encarnacion; King, Helen E.; Patiño-López, Luis D.; Putnis, Christine V.; Geisler, Thorsten; Rodriguez-Navarro, Carlos M.; Putnis, Andrew

    2015-04-01

    The chemical weathering of carbonate and silicate minerals on the Earth's surface controls important geochemical processes such as erosion rates and soil formation, ore genesis or climate evolution. The dissolution of most of these minerals is typically incongruent, and results in the formation of surface coatings (altered layers, also known as leached layers). These coatings may significantly affect mineral dissolution rates over geological timescales, and therefore a great deal of research has been conducted on them. However, the mechanism of leached layer formation is a matter of vigorous debate. Here we report on an in situ atomic force microscopy (AFM) and real-time Mach-Zehnder phase-shift interferometry (PSI) study of the dissolution of wollastonite, CaSiO3, and dolomite, CaMg(CO3)2, as an example of surface coating formation during acidic weathering of multicomponent minerals. Our in situ results provide clear direct experimental evidence that leached layers are formed in a tight interface-coupled two-step process: stoichiometric dissolution of the pristine mineral surfaces and subsequent precipitation of a secondary phase (silica in the case of wollastonite, or hydrated magnesium carbonate in the case of dolomite) from a supersaturated boundary layer of fluid in contact with the mineral surface. This occurs despite the bulk solution remaining undersaturated with respect to the secondary phase. The validation of such a mechanism given by the results reported here completely changes the conceptual framework concerning the mechanism of chemical weathering, and differs significantly from the concept of preferential leaching of cations postulated by most currently accepted incongruent dissolution models.

  14. Lithium distribution and isotopic fractionation during chemical weathering and soil formation in a loess profile

    Science.gov (United States)

    Tsai, Pei-Hsuan; You, Chen-Feng; Huang, Kuo-Fang; Chung, Chuan-Hisung; Sun, You-Bin

    2014-06-01

    Lithium (Li) is a fluid-mobile element and δ7Li in secondary deposits represents an excellent proxy for silicate weathering and authigenic mineral formation. The soil samples from 1205 to 1295 cm in the Weinan profile, one of the best developed loess-paleosol sequences covering the last glacial-interglacial climatic cycle, were collected and chemically separated into detritus and carbonate fractions for subsequent analyses of Li, δ7Li, major and trace elements. Other desert specimens (i.e., Qaidam Desert, Tengger Desert, Badain Juran Desert and Taklimakan Desert) near the Chinese Loess Plateau (CLP) and various standard clays were analyzed for assisting provenance determination. The Li and δ7Li distributions in the detritus are rather homogeneous, 1.4-2.0 μg/g and +2.5‰ to +4.7‰, respectively, compared with the carbonate fraction. The detrital δ7Li varies systematically with magnetic susceptibility and grain size changes, reflecting significant Li isotopic variation associated with sources and mineralogy of detrital material. On the other hand, Li and δ7Li in carbonates show large changes, 781-963 ng/g and -4.1‰ to +10.2‰, respectively. These carbonate δ7Li correlated well with the estimated index of chemical weathering, as a result of Li mobilization and soil formation during chemical weathering.

  15. Determining rates of chemical weathering in soils - Solute transport versus profile evolution

    Science.gov (United States)

    Stonestrom, D.A.; White, A.F.; Akstin, K.C.

    1998-01-01

    SiO2 fluxes associated with contemporary solute transport in three deeply weathered granitoid profiles are compared to bulk SiO2 losses that have occurred during regolith development. Climates at the three profiles range from Mediterranean to humid to tropical. Due to shallow impeding alluvial layers at two of the profiles, and seasonally uniform rainfall at the third, temporal variations in hydraulic and chemical state variables are largely attenuated below depths of 1-2 m. This allows current SiO2 fluxes below the zone of seasonal variations to be estimated from pore-water concentrations and average hydraulic flux densities. Mean-annual SiO2 concentrations were 0.1-1.5 mM. Hydraulic conductivities for the investigated range of soil-moisture saturations ranged from 10-6 m s-1. Estimated hydraulic flux densities for quasi-steady portions of the profiles varied from 6 x 10-9 to 14 x 10-9 m s-1 based on Darcy's law and field measurements of moisture saturations and pressure heads. Corresponding fluid-residence times in the profiles ranged from 10 to 44 years. Total SiO2 losses, based on chemical and volumetric changes in the respective profiles, ranged from 19 to 110 kmoles SiO2 m-2 of land surface as a result of 0.2-0.4 Ma of chemical weathering. Extrapolation of contemporary solute fluxes to comparable time periods reproduced these SiO2 losses to about an order of magnitude. Despite the large range and non-linearity of measured hydraulic conductivities, solute transport rates in weathering regoliths can be estimated from characterization of hydrologic conditions at sufficiently large depths. The agreement suggests that current weathering rates are representative of long-term average weathering rates in the regoliths.SiO2 fluxes associated with contemporary solute transport in three deeply weathered granitoid profiles are compared to bulk SiO2 losses during regolith development. Due to shallow impeding alluvial layers at two of the profiles, and seasonally uniform

  16. Unifying natural and laboratory chemical weathering with interfacial dissolution-reprecipitation: A study based on the nanometer-scale chemistry of fluid-silicate interfaces

    International Nuclear Information System (INIS)

    Chemical weathering reactions of rocks at Earth's surface play a major role in the chemical cycle of elements, and represent one of the major abiotic sinks for atmospheric CO2. Because natural chemical weathering reactions occur at different and more complex chemical conditions than laboratory-based weathering experiments, it has long been thought that the underlying fluid-mineral interaction mechanisms are different. In contrast to most previous studies that have relied on ion, electron, and X-ray beam techniques (characterized by pm to mm lateral spatial resolution) to obtain chemical depth profiles of altered mineral surfaces, we have used high resolution and energy filtered transmission electron microscopy (HRTEM, EFTEM) to study mineral-fluid interfaces using TEM foils cut directly across the reaction boundaries. This allowed measurements to be made directly in cross section at nanometer to sub-nanometer-resolution. Our measurements of the surface chemistry and structure of a large suite of laboratory-altered and field-weathered silicate minerals indicate the general presence of surface layers composed of amorphous, hydrated silica. In each case, the boundary between the parent mineral and the corresponding silica layer is characterized by sharp, nanometer-scale chemical concentration jumps that are spatially coincident with a very sharp crystalline-amorphous interfacial boundary. TEM, atomic force microscopy (AFM), and aqueous chemistry data suggest that the surface layers are permeable to fluids. Taken together, our measurements are not in agreement with currently accepted models for chemical weathering, in particular the leached layer theory. Most importantly, our data provide critical evidence for a single mechanism based on interfacial dissolution-reprecipitation. This concept not only unifies weathering processes for the first time, but we also suggest that nanoscale-surface processes can have a potentially negative impact on CO2 uptake associated with

  17. Weather elements, chemical air pollutants and airborne pollen influencing asthma emergency room visits in Szeged, Hungary: performance of two objective weather classifications

    Science.gov (United States)

    Makra, László; Puskás, János; Matyasovszky, István; Csépe, Zoltán; Lelovics, Enikő; Bálint, Beatrix; Tusnády, Gábor

    2015-09-01

    Weather classification approaches may be useful tools in modelling the occurrence of respiratory diseases. The aim of the study is to compare the performance of an objectively defined weather classification and the Spatial Synoptic Classification (SSC) in classifying emergency department (ED) visits for acute asthma depending from weather, air pollutants, and airborne pollen variables for Szeged, Hungary, for the 9-year period 1999-2007. The research is performed for three different pollen-related periods of the year and the annual data set. According to age and gender, nine patient categories, eight meteorological variables, seven chemical air pollutants, and two pollen categories were used. In general, partly dry and cold air and partly warm and humid air aggravate substantially the symptoms of asthmatics. Our major findings are consistent with this establishment. Namely, for the objectively defined weather types favourable conditions for asthma ER visits occur when an anticyclonic ridge weather situation happens with near extreme temperature and humidity parameters. Accordingly, the SSC weather types facilitate aggravating asthmatic conditions if warm or cool weather occur with high humidity in both cases. Favourable conditions for asthma attacks are confirmed in the extreme seasons when atmospheric stability contributes to enrichment of air pollutants. The total efficiency of the two classification approaches is similar in spite of the fact that the methodology for derivation of the individual types within the two classification approaches is completely different.

  18. Idaho Chemical Processing Plant Process Efficiency improvements

    Energy Technology Data Exchange (ETDEWEB)

    Griebenow, B.

    1996-03-01

    In response to decreasing funding levels available to support activities at the Idaho Chemical Processing Plant (ICPP) and a desire to be cost competitive, the Department of Energy Idaho Operations Office (DOE-ID) and Lockheed Idaho Technologies Company have increased their emphasis on cost-saving measures. The ICPP Effectiveness Improvement Initiative involves many activities to improve cost effectiveness and competitiveness. This report documents the methodology and results of one of those cost cutting measures, the Process Efficiency Improvement Activity. The Process Efficiency Improvement Activity performed a systematic review of major work processes at the ICPP to increase productivity and to identify nonvalue-added requirements. A two-phase approach was selected for the activity to allow for near-term implementation of relatively easy process modifications in the first phase while obtaining long-term continuous improvement in the second phase and beyond. Phase I of the initiative included a concentrated review of processes that had a high potential for cost savings with the intent of realizing savings in Fiscal Year 1996 (FY-96.) Phase II consists of implementing long-term strategies too complex for Phase I implementation and evaluation of processes not targeted for Phase I review. The Phase II effort is targeted for realizing cost savings in FY-97 and beyond.

  19. Idaho Chemical Processing Plant Process Efficiency improvements

    International Nuclear Information System (INIS)

    In response to decreasing funding levels available to support activities at the Idaho Chemical Processing Plant (ICPP) and a desire to be cost competitive, the Department of Energy Idaho Operations Office (DOE-ID) and Lockheed Idaho Technologies Company have increased their emphasis on cost-saving measures. The ICPP Effectiveness Improvement Initiative involves many activities to improve cost effectiveness and competitiveness. This report documents the methodology and results of one of those cost cutting measures, the Process Efficiency Improvement Activity. The Process Efficiency Improvement Activity performed a systematic review of major work processes at the ICPP to increase productivity and to identify nonvalue-added requirements. A two-phase approach was selected for the activity to allow for near-term implementation of relatively easy process modifications in the first phase while obtaining long-term continuous improvement in the second phase and beyond. Phase I of the initiative included a concentrated review of processes that had a high potential for cost savings with the intent of realizing savings in Fiscal Year 1996 (FY-96.) Phase II consists of implementing long-term strategies too complex for Phase I implementation and evaluation of processes not targeted for Phase I review. The Phase II effort is targeted for realizing cost savings in FY-97 and beyond

  20. Chemical weathering of granitic rocks: an experimental approach and Pb-Li isotope tracing

    International Nuclear Information System (INIS)

    In order to characterize water-rock interactions in granite, we performed laboratory experiments and Pb-Li isotope tracing. The aim of the present work is to better constrain the processes of water-rock interactions, both in terms of source and extent of weathering, by measuring major and trace elements, as well as Pb and Li isotope signatures. (authors)

  1. Effects of climate and mineral supply rates on long-term chemical weathering rates in granitic landscapes

    Science.gov (United States)

    Riebe, C. S.; Kirchner, J. W.; Finkel, R. C.

    2003-12-01

    We used cosmogenic nuclide and geochemical mass balance methods to measure long-term rates of chemical weathering and physical erosion of granitic terrain. Our 43 study sites encompass widely varying climates and denudation rates; mean annual temperatures vary from 2 to 32\\deg C, average annual precipitation spans a 20-fold range (from 22 to 420 cm/yr), and denudation rates vary by 32-fold across our sites. Long-term chemical weathering rates for these 43 sites range from 0 to 173 t km-2 yr-1, in several cases exceeding the highest granitic weathering rates on record from previous work. Chemical weathering rates are highest at sites with rapid denudation rates, consistent with strong coupling between rates of chemical weathering and mineral supply from physical erosion of rock. To account for effects of mineral supply in analyzing how climate affects chemical weathering, we introduce the "Weathering Intensity Factor" (WIF), the ratio of chemical weathering rate to physical erosion rate. WIF's increase systematically with average annual precipitation and mean annual temperature, both for the soil as a whole, and for individual component elements including Si, Na, and Ca. Between 59 and 79 percent of the variance in WIF's can be explained by a simple Arrhenius-like relationship based on mean annual temperature and average annual precipitation. Moreover, when we couple this Arrhenius relationship with our measurements of long-term erosion rates, we obtain a simple prediction equation that explains between 79 and 93 percent of the variance in long-term chemical weathering rates. The temperature-dependence of WIF is roughly half what one would expect from laboratory measurements of activation energies for feldspar weathering. Our results imply that the strength of climate change feedbacks between temperature and silicate weathering rates may be weaker than previously thought, at least in actively eroding, unglaciated terrain similar to our study sites. Our results

  2. Kenya public weather processed by the Global Yield Gap Atlas project

    OpenAIRE

    Groot, de, W.T.; Adimo, A.O.; Claessens, L.F.G.; Wart, Van, Justin; Bussel, van, G.J.; Grassini, P.; Wolf, J; Guilpart, Nicolas; Boogaard, H. L.; Oort, van, E.D.; Yang, H; Ittersum, van, M.K.; Cassman, K. G.

    2015-01-01

    The Global Yield Gap Atlas project (GYGA - http://yieldgap.org ) has undertaken a yield gap assessment following the protocol recommended by van Ittersum et. al. (van Ittersum et. al., 2013). One part of the activities consists of collecting and processing weather data as an input for crop simulation models in sub-Saharan African countries including Kenya. This publication covers weather data for 10 locations in Kenya. The project looked for good quality weather data in areas where crops are ...

  3. Reach-scale evidence for feedbacks among chemical weathering, rock strength and erosion in bedrock rivers across Kohala Peninsula, Hawai'i

    Science.gov (United States)

    Murphy, B. P.; Johnson, J. P.; Gasparini, N. M.; Hancock, G. S.; Small, E. E.

    2015-12-01

    Bedrock river downcutting is usually conceptualized in terms of shear-stress dependent erosion processes, such as abrasion and plucking. Many studies of climatic control on erosion have focused on the effect of rainfall rate on discharge. However, the erodibility of bedrock can also be influenced by climate-dependent chemical weathering. We show that this mechanism can not only influence erosion patterns and rates, but also reach-scale bedrock topography. First, we present a new numerical model that describes and explores the feedbacks among chemical weathering, rock strength and erosion rate. Second, we present reach-scale field data demonstrating interactions among chemical weathering, rock strength, abrasion, and channel morphology. Across an extreme rainfall gradient on Kohala Peninsula, Hawai'i, we demonstrate that bedrock chemical weathering leads to the development of significant asymmetries in rock strength across features that are exposed to abrasion. Using a type-N Schmidt hammer, we measured the in-situ rock strength across 23 morphologic features of bedrock exposed in the stream beds of rivers, and found that upstream faces are consistently stronger, by an average of 38%, than downstream faces. Measured rock strengths suggest that the erodibilty of downstream (lee) faces may be as much as 20 times higher than corresponding upstream faces where weaker weathered material is efficiently abraded away. The asymmetrical pattern of rock strength does not necessarily lead to strongly asymmetrical morphologies, because although sediment impacts may result in more erosion on the weaker downstream face, the frequency of abrasion wear is substantially less frequent. Although the physical evidence for the chemical weathering is more frequently removed from the upstream face, these results demonstrate that, particularly in regions with higher local rainfall and weathering rates, chemical weathering induced strength reduction is a specific mechanism by which climate

  4. Weathering profiles in granitoid rocks of the Sila Massif uplands, Calabria, southern Italy: New insights into their formation processes and rates

    Science.gov (United States)

    Scarciglia, Fabio; Critelli, Salvatore; Borrelli, Luigi; Coniglio, Sabrina; Muto, Francesco; Perri, Francesco

    2016-05-01

    In this paper we characterized several weathering profiles developed on granitoid rocks in the Sila Massif upland (Calabria, southern Italy), integrating detailed macro- and micromorphological observations with physico-mechanical field tests and petrographic, mineralogical and geochemical analyses. We focused our attention on the main weathering and pedogenetic processes, trying to understand apparent discrepancies between weathering grade classes based on field description and geomechanical properties, and two common weathering indices, such as the micropetrographic index (Ip) and the chemical index of alteration (CIA). Our results showed that sericite on plagioclase and biotite chloritization, that represent inherited features formed during late-stage hydrothermal alteration of granitoid rocks, may cause an overestimation of the real degree of weathering of primary mineral grains under meteoric conditions, especially in lower weathering grade classes. Moreover, the frequent identification of Fe-Mn oxides and clay coatings of illuvial origin (rather than or in addition to those formed in situ), both at the macro- and microscale, may also explain an overestimation of the weathering degree with respect to field-based classifications. Finally, some apparent inconsistencies between field geomechanical responses and chemical weathering were interpreted as related to physical weathering processes (cryoclastism and thermoclastism), that lead to rock breakdown even when chemical weathering is not well developed. Hence, our study showed that particular caution is needed for evaluating weathering grades, because traditional field and geochemical-petrographic tools may be biased by inherited hydrothermal alteration, physical weathering and illuvial processes. On the basis of chronological constraints to soil formation obtained from a 42 ka-old volcanic input (mixed to granite parent materials) detected in the soil cover of the Sila Massif upland, a first attempt to estimate

  5. Personal Simulator of Chemical Process

    Institute of Scientific and Technical Information of China (English)

    吴重光

    2002-01-01

    The Personal Simulator of chemical process (PS) means that fully simulationsoftware can be run on one personal computer. This paper describes the kinds of PSprograms, its features, the graphic functions and three examples. PS programs are allbased on one object-oriented and real-time simulation software environment. Authordevelops this simulation software environment. An example of the batch reaction kineticsmodel is also described. Up to now a lot of students in technical schools and universitieshave trained on PS. The training results are very successful.

  6. Chemical models for martian weathering profiles: Insights into formation of layered phyllosilicate and sulfate deposits

    Science.gov (United States)

    Zolotov, Mikhail Yu.; Mironenko, Mikhail V.

    2016-09-01

    Numerical chemical models for water-basalt interaction have been used to constrain the formation of stratified mineralogical sequences of Noachian clay-bearing rocks exposed in the Mawrth Vallis region and in other places on cratered martian highlands. The numerical approaches are based on calculations of water-rock type chemical equilibria and models which include rates of mineral dissolution. Results show that the observed clay-bearing sequences could have formed through downward percolation and neutralization of acidic H2SO4-HCl solutions. A formation of weathering profiles by slightly acidic fluids equilibrated with current atmospheric CO2 requires large volumes of water and is inconsistent with observations. Weathering by solutions equilibrated with putative dense CO2 atmospheres leads to consumption of CO2 to abundant carbonates which are not observed in clay stratigraphies. Weathering by H2SO4-HCl solutions leads to formation of amorphous silica, Al-rich clays, ferric oxides/oxyhydroxides, and minor titanium oxide and alunite at the top of weathering profiles. Mg-Fe phyllosilicates, Ca sulfates, zeolites, and minor carbonates precipitate from neutral and alkaline solutions at depth. Acidic weathering causes leaching of Na, Mg, and Ca from upper layers and accumulation of Mg-Na-Ca sulfate-chloride solutions at depth. Neutral MgSO4 type solutions dominate in middle parts of weathering profiles and could occur in deeper layers owing to incomplete alteration of Ca minerals and a limited trapping of Ca to sulfates. Although salts are not abundant in the Noachian geological formations, the results suggest the formation of Noachian salty solutions and their accumulation at depth. A partial freezing and migration of alteration solutions could have separated sulfate-rich compositions from low-temperature chloride brines and contributed to the observed diversity of salt deposits. A Hesperian remobilization and release of subsurface MgSO4 type solutions into newly

  7. Image processing for hazard recognition in on-board weather radar

    Science.gov (United States)

    Kelly, Wallace E. (Inventor); Rand, Timothy W. (Inventor); Uckun, Serdar (Inventor); Ruokangas, Corinne C. (Inventor)

    2003-01-01

    A method of providing weather radar images to a user includes obtaining radar image data corresponding to a weather radar image to be displayed. The radar image data is image processed to identify a feature of the weather radar image which is potentially indicative of a hazardous weather condition. The weather radar image is displayed to the user along with a notification of the existence of the feature which is potentially indicative of the hazardous weather condition. Notification can take the form of textual information regarding the feature, including feature type and proximity information. Notification can also take the form of visually highlighting the feature, for example by forming a visual border around the feature. Other forms of notification can also be used.

  8. Iron-sulfur mineralogy of Mars: Magmatic evolution and chemical weathering products

    International Nuclear Information System (INIS)

    Models for the evolution of sulfide minerals on Mars and reaction pathways to their oxidative weathering products in Martian regolith have been proposed based on petrogenetic associations between komatiitic rock types, Viking geochemical data, SNC meteorites, and terrestrial Fe-Ni sulfide deposits. To test the weathering model, komatiitic pyrrhotites and olivines were exposed to sulfuric acid solutions, with and without dissolved ferric iron added to simulate deep-weathering processes, and the reaction products were identified by Mossbauer spectroscopy. Secondary FeS2 (pyrite or marcasite), FeOOH (goethite), and possibly jarosite were formed from pyrrhotite, while olivine was oxidized to nanophase goethite. These results suggest that on Mars, acidic groundwater induced pyrrhotite → FeS2 → FeOOH (+jarosite) oxidative weathering reactions, particularly in the presence of dissolved Fe3+. Such gossaniferous materials occurring in Martian regolith were derived mainly from Fe-Ni sulfides associated with komatiitic basalts and not from sulfides occurring in calc-alkaline porphyry copper deposits, granitic hydrothermal veins, sediment-hosted PbS-ZnS ores, etc., which presumably did not evolve on Mars due to the virtual lack of plate tectonic activity there

  9. Element geochemistry of weathering profile of dolomitite and its implications for the average chemical composition of the upper-continental crust--Case studies from the Xinpu profile,northern Guizhou Province,China

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Geochemical behavior of chemical elements is studied in a dolomitite weathering profile in upland of karst terrain in northern Guizhou.Two stages can be recognized during the process of in situ weathering of dolomitite:the stage of sedentary accumulation of leaching residue of dolomitite and the stage of chemical weathering evolution of sedentary soil.Ni,Cr,Mo,W and Ti are the least mobile elements with reference to Al.The geochemical behavior of REE is similar to that observed in weathering of other types of rocks.Fractionation of REE is noticed during weathering,and the two layers of REE enrichments are thought to result from downward movement of the weathering front in response to changes in the environment.It is considered that the chemistry of the upper part of the profile,which was more intensively weathered,is representative of the mobile components of the upper curst at the time the dolomitite was formed,while the less weathered lower profile is chemically representative of the immobile constitution.Like glacial till and loess,the "insoluble" materials in carbonate rocks originating from chemical sedimentation may also provide valuable information about the average chemical composition of the upper continental crust.

  10. Operational, regional-scale, chemical weather forecasting models in Europe. Chapter 61

    Czech Academy of Sciences Publication Activity Database

    Kukkonen, J.; Balk, T.; Schultz, D.M.; Baklanov, A.; Klein, T.; Miranda, A.I.; Monteiro, A.; Hirtl, M.; Lehtinen, K.; Karatzas, K.; San José, R.; Astitha, M.; Kallos, G.; Schaap, M.; Reimer, E.; Jakobs, H.; Tarvainen, V.; Boy, M.; Peuch, V.H.; PoupKou, A.; Kioutsioukis, I.; Finardi, S.; Sofiev, M.; Eben, Kryštof; Sokhi, R.

    Dordrecht: Springer Science+Business Media B.V, 2011 - (Steyn, D.; Castelli, S.), s. 359-365. (NATO Science for Peace and Security Series C: Environmetal Security. 4). ISBN 978-94-007-1358-1. ISSN 1874-6519. [NATO/SPS International Technical Meeting on Air Pollution Modeling and its Applications /31./. Torino (IT), 27.09.2010-01.10.2010] Institutional research plan: CEZ:AV0Z10300504 Keywords : chemical weather * scientific model evaluation * forecasting model Subject RIV: DI - Air Pollution ; Quality

  11. Idaho Chemical Processing Plant safety document ICPP hazardous chemical evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Harwood, B.J.

    1993-01-01

    This report presents the results of a hazardous chemical evaluation performed for the Idaho Chemical Processing Plant (ICPP). ICPP tracks chemicals on a computerized database, Haz Track, that contains roughly 2000 individual chemicals. The database contains information about each chemical, such as its form (solid, liquid, or gas); quantity, either in weight or volume; and its location. The Haz Track database was used as the primary starting point for the chemical evaluation presented in this report. The chemical data and results presented here are not intended to provide limits, but to provide a starting point for nonradiological hazards analysis.

  12. Role of minerals properties on leaching process of weathered crust elution-deposited rare earth ore

    Institute of Scientific and Technical Information of China (English)

    肖燕飞; 刘向生; 冯宗玉; 黄小卫; 黄莉; 陈迎迎; 吴文远

    2015-01-01

    Granite belonged to intrusive rock and volcanic was extrusive rock. There may be many differences in their degree of weathering and mineral chemical composition. The present study investigated the minerals properties and the leaching mechanism of the granitic weathered crust elution-deposited rare earth ore from Longnan Rare Earth Mine area (LN ores) and volcanic weathered crust elution-deposited rare earth ore from Liutang Rare Earth Mine area (LT ores). The X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) were used to characterize the phase of rare earth ores. The particle size distributions and main composition of the ore were also presented in this paper. The leaching mechanisms of two kinds of rare earth ores were analyzed with different kinetics models and could be described by the shrinking-core model. They were all inner diffusion-controlled leaching processes. The leaching equation of the kinetics of the LN ores could be expressed as:4 LN LN 1.096 10 2/3 0.377 8.314 0 2 3=0.1061 (1 ) Tr e tη η×−−− − −, leaching equation of kinetics of LT ores was 3 LT LT 4.640 10 2/3 0.411 8.314 0 32 3=8.33 101 (1 ) Tr e tη η×−− −×− − −. The rare earth leaching rate of LT ores was always lower in the same condition, and it would need more time and more (NH4)2SO4 consump-tion to achieve the same rare earth leaching efficiency, which would lead to more serious ammonia-nitrogen pollution. Therefore, magnesium salt was proposed as the leaching agent to eliminate ammonia-nitrogen pollution and further studies would be taken in the future.

  13. Major ion chemistry of the Son River, India: Weathering processes, dissolved fluxes and water quality assessment

    Indian Academy of Sciences (India)

    Chinmaya Maharana; Sandeep Kumar Gautam; Abhay Kumar Singh; Jayanth K Tripathi

    2015-08-01

    River Son, draining diverse lithologies in the subtropical climate of the peninsular sub-basin of the Ganga basin, is one of the major tributaries of the Ganga River. The chemistry of major ions in the surface water of the Son River was studied in detail to determine various source(s) and processes controlling its water chemistry, seasonal and spatial variations in water chemistry, dissolved fluxes and chemical denudation rate (CDR). The study shows that Ca2+, Mg2+ and HCO$^{-}_{3}$ are major ionic species in the river water. Most of the measured parameters exhibit a relatively lower concentration in the post-monsoon as compared to pre-monsoon season. The water chemistry highlights the influence of continental weathering aided by secondary contributions from ground water, saline/alkaline soils and anthropogenic activities in the catchment. Results also reflect the dominance of carbonate weathering over silicate weathering in controlling water composition. The Son River delivers about 4.2 million tons of dissolved loads annually to the Ganga River, which accounts for ∼6% of the total annual load carried by the Ganga River to the Bay of Bengal. The average CDR of the Son River is 59.5 tons km−2 yr−1, which is less than the reported 72 tons km−2 yr−1 of the Ganga River and higher than the global average of 36 tons km−2 yr−1. The water chemistry for the pre-monsoon and post-monsoon periods shows a strong seasonal control on solute flux and CDR values. The water chemistry indicates that the Son River water is good to excellent in quality for irrigation and also suitable for drinking purposes.

  14. Stochastic processes in chemical physics

    CERN Document Server

    Shuler, K E

    2009-01-01

    The Advances in Chemical Physics series provides the chemical physics and physical chemistry fields with a forum for critical, authoritative evaluations of advances in every area of the discipline. Filled with cutting-edge research reported in a cohesive manner not found elsewhere in the literature, each volume of the Advances in Chemical Physics series serves as the perfect supplement to any advanced graduate class devoted to the study of chemical physics.

  15. Environmental tracers for elucidating the weathering process in a phosphogypsum disposal site: Implications for restoration

    Science.gov (United States)

    Pérez-López, Rafael; Nieto, José M.; de la Rosa, Jesús D.; Bolívar, Juan P.

    2015-10-01

    This study provides geochemical data with the aim of identifying and tracing the weathering of phosphogypsum wastes stack-piled directly on salt-marshes of the Tinto River (Estuary of Huelva, SW Spain). With that purpose, different types of highly-polluted acid solutions were collected in the stack. Connection between these solutions and the estuarine environment was studied by geochemical tracers, such as rare earth elements (REE) and their North American Shale Composite (NASC)-normalized patterns and Cl/Br ratios. Phosphogypsum-related wastewaters include process water stored on the surface, pore-water contained in the phosphogypsum profile and edge outflow water emerging from inside the stack. Edge outflow waters are produced by waterlogging at the contact between phosphogypsum and the nearly impermeable marsh surface and discharge directly into the estuary. Process water shows geochemical characteristics typical of phosphate fertilizers, i.e. REE patterns with an evident enrichment of heavy-REE (HREE) with respect to middle-REE (MREE) and light-REE (LREE). By contrast, REE patterns of deeper pore-water and edge outflows are identical to those of Tinto River estuary waters, with a clear enrichment of MREE relative to LREE and HREE denoting influence of acid mine drainage. Cl/Br ratios of these solutions are very close to that of seawater, which also supports its estuarine origin. These findings clearly show that process water is not chemically connected with edge outflows through pore-waters, as was previously believed. Phosphogypsum weathering likely occurs by an upward flow of seawater from the marsh because of overpressure and permeability differences. Several recommendations are put forward in this study to route restoration actions, such as developing treatment systems to improve the quality of the edge outflow waters before discharging to the receiving environment.

  16. Experiments To Demonstrate Chemical Process Safety Principles.

    Science.gov (United States)

    Dorathy, Brian D.; Mooers, Jamisue A.; Warren, Matthew M.; Mich, Jennifer L.; Murhammer, David W.

    2001-01-01

    Points out the need to educate undergraduate chemical engineering students on chemical process safety and introduces the content of a chemical process safety course offered at the University of Iowa. Presents laboratory experiments demonstrating flammability limits, flash points, electrostatic, runaway reactions, explosions, and relief design.…

  17. Chemical reagent and process for refuse disposal

    International Nuclear Information System (INIS)

    A process for treating refuse by mixing them with a reactive chemical and a puzzolana-type material. Said chemical includes a retarding agent which modifies the viscosity and an accelerating agent. (author)

  18. Technical Note: An open source library for processing weather radar data (wradlib)

    OpenAIRE

    Heistermann, M.; Jacobi, S.; T. Pfaff

    2013-01-01

    The potential of weather radar observations for hydrological and meteorological research and applications is undisputed, particularly with increasing world-wide radar coverage. However, several barriers impede the use of weather radar data. These barriers are of both scientific and technical nature. The former refers to inherent measurement errors and artefacts, the latter to aspects such as reading specific data formats, geo-referencing, visualisation. The radar processing library wradlib is...

  19. Technical Note: An open source library for processing weather radar data (wradlib)

    OpenAIRE

    T. Pfaff; Jacobi, S.; Heistermann, M.

    2012-01-01

    The potential of weather radar observations for hydrological and meteorological research and applications is undisputed, particularly with increasing world-wide radar coverage. However, several barriers impede the use of weather radar data. These barriers are of both scientific and technical nature. The former refers to inherent measurement errors and artefacts, the latter to aspects such as reading specific data formats, geo-referencing, visualisation. The radar processing library wradlib is...

  20. Element geochemistry of weathering profile of dolomitite and its implications for the average chemical composition of the upper-continental crust——Case studies from the Xinpu profile, northern Guizhou Province, China

    Institute of Scientific and Technical Information of China (English)

    季宏兵; 欧阳自远; 王世杰; 周德全

    2000-01-01

    Geochemical behavior of chemical elements is studied in a dolomitite weathering profile in upland of karst terrain in northern Guizhou. Two stages can be recognized during the process of in situ weathering of dolomitite: the stage of sedentary accumulation of leaching residue of dolomitite and the stage of chemical weathering evolution of sedentary soil. Ni, Cr, Mo, W and Ti are the least mobile elements with reference to Al. The geochemical behavior of REE is similar to that observed in weathering of other types of rocks. Fractionation of REE is noticed during weathering, and the two layers of REE enrichments are thought to result from downward movement of the weathering front in response to changes in the environment. It is considered that the chemistry of the upper part of the profile, which was more intensively weathered, is representative of the mobile components of the upper curst at the time the dolomitite was formed, while the less weathered lower profile is chemically representative of the immo

  1. Effects of chemical weathering on infrared spectra of Columbia River Basalt and spectral interpretations of martian alteration

    Science.gov (United States)

    Michalski, Joseph R.; Kraft, Michael D.; Sharp, Thomas G.; Christensen, Philip R.

    2006-08-01

    We investigated the mineralogy of basalt weathering rinds and fresh basaltic rocks using visible/near-infrared (VNIR) ( λ = 0.4-2.5 μm) and thermal emission ( λ = 6-30 μm) spectroscopy to 1) constrain the effects of chemical weathering on rock spectra, and 2) further understand the context of infrared spectra of Mars, which may contain evidence for weathered rocks and particulates derived from them. VNIR spectra of weathered rock surfaces are generally redder and brighter than fresh surfaces. Thermal infrared spectra of weathered basalts show evidence for aluminous opal and clay minerals (or clay precursor mineraloids) in natural surfaces. Supporting VNIR observations generally do not show the same evidence for neoformed clays or silica because of their textural occurrence as thin coatings and microfracture-fill, and possibly due to poor crystallinity of the aluminosilicate weathering products in this context. Spectral trends observed at Mars, such as the detection of low to moderate (10-25%) abundances of silica and clay that are observed in the thermal infrared but not in the VNIR, are therefore consistent with trends observed for natural rock surfaces in the laboratory. The combined use of thermal infrared and VNIR suggest that vast areas of martian dark regions contain sandy-rocky basaltic materials with weathering rinds and thin coatings that could have formed in conditions of relatively low water/rock ratios.

  2. The communicative process of weather forecasts issued in the probabilistic form (Italian original version

    Directory of Open Access Journals (Sweden)

    Alessio Raimondi

    2009-03-01

    Full Text Available One of the main purposes of weather forecasting is that of protecting weather-sensitive human activities. Forecasts issued in the probabilistic form have a higher informative content, as opposed to deterministic one, since they bear information that give also a measure of their own uncertainty. However, in order to make an appropriate and effective use of this kind of forecasts in an operational setting, communication becomes significatively relevant.The present paper, after having briefly examined the weather forecasts concerning Hurricane Charley (August 2004, tackles the issue of the communicative process in detail.The bottom line of this study is that for the weather forecast to achieve its best predictive potential, an in-depth analysis of communication issues is necessary.

  3. Chemical weathering, mass loss, and dust inputs across a climate by time matrix in the Hawaiian Islands

    Science.gov (United States)

    Porder, Stephen; Hilley, George E.; Chadwick, Oliver A.

    2007-06-01

    We determined the total mass loss and rate of chemical weathering from three minimally eroded, Hawaiian lava flows that are ˜ 10, 170, and 350 ka old. Using a backhoe, we sampled the entire weathering zone at 28 sites and measured the depletion or enrichment of each major element in each soil horizon relative to parent material. We were able to assess the influence of both climate and substrate age on chemical weathering because each flow crosses a precipitation gradient from ˜ 600 to ˜ 2500 mm yr - 1 . Mass loss rates were highest for the 0-10 ka interval under the wettest climatic conditions (54 t km - 2 yr - 1 ), and decreased to near zero in the wet sites during the 10-170 and 170-350 ka intervals. Not surprisingly, weathering rates were lower in drier sites; ˜ 24 t km - 2 yr - 1 from 0-10 ka to < 2 t km - 2 yr - 1 thereafter. However the effects of precipitation were non-linear. There was a precipitation threshold below which mass loss was relatively small, and above which mass loss was substantial but insensitive to increased rainfall. Chemical weathering rates depend on tectonic uplift, erosion, climate, rock type or some combination thereof. By working on stable, uneroded surfaces of a single rock type across a well-constrained precipitation gradient, we were able to identify another potential driver: the rate of dust deposition. Although Hawaíi is one of the least dusty places in the northern hemisphere, dust inputs reached 82% of the total mass loss from the weathering zone at some sites, and averaged 30% on the 170 ka flow. This highlights the potential importance of dust as a component of observed weathering fluxes from catchments worldwide.

  4. Chemical Processing Department monthly report, January 1961

    Energy Technology Data Exchange (ETDEWEB)

    1961-02-21

    This report, from the Chemical Processing Department at HAPO for January 1961, discusses the following: Production operation; Purex and Redox operation; Finished products operation; maintenance; Financial operations, facilities engineering; research; employee relations; and special separation processing and auxiliaries operation.

  5. The rate of chemical weathering of pyrite on the surface of Venus

    Science.gov (United States)

    Fegley, B., Jr.; Lodders, K.

    1993-01-01

    This abstract reports results of an experimental study of the chemical weathering of pyrite (FeS2) under Venus-like conditions. This work, which extends the earlier study by Fegley and Treiman, is part of a long range research program to experimentally measure the rates of thermochemical gas-solid reactions important in the atmospheric-lithospheric sulfur cycle on Venus. The objectives of this research are (1) to measure the kinetics of thermochemical gas-solid reactions responsible for both the production (e.g., anhydrite formation) and destruction (e.g., pyrrhotite oxidation) of sulfur-bearing minerals on the surface of Venus and (2) to incorporate these and other constraints into holistic models of the chemical interactions between the atmosphere and surface of Venus. Experiments were done with single crystal cubes of natural pyrite (Navajun, Logrono, Spain) that were cut and polished into slices of known weight and surface area. The slices were isothermally heated at atmospheric pressure in 99.99 percent CO2 (Coleman Instrument Grade) at either 412 C (685 K) or 465 C (738 K) for time periods up to 10 days. These two isotherms correspond to temperatures at about 6 km and 0 km altitude, respectively, on Venus. The reaction rate was determined by measuring the weight loss of the reacted slices after removal from the furnace. The reaction products were characterized by X-ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy on the SEM.

  6. Space Weather data processing and Science Gateway for the Van Allen Probes

    Science.gov (United States)

    Romeo, G.; Barnes, R. J.; Weiss, M.; Fox, N. J.; Mauk, B.; Potter, M.; Kessel, R.

    2013-12-01

    A near real-time data processing pipeline for the Space Weather broadcast data from the Van Allen Probes is presented. The Van Allen Probes broadcasts a sub-set of the science data in real-time when not downlinking the principal science data. This broadcast is received by several ground stations and relayed to APL in near real time to be ingested into the space weather processing pipeline. This pipeline processes the available level zero space weather data into higher level science data products. These products are made available to the public via the Van Allen Probes Science Gateway website (http://athena.jhuapl.edu). The website acts as pivotal point though which all other instrument SOC's can be accessed. Several other data products (e.g KP/DST indices) and tools (e.g orbit calculator) are made also available to the general public.

  7. Plasma-chemical processes and systems

    International Nuclear Information System (INIS)

    The direct applications of plasma technology on chemistry and metallurgy are presented. The physical fundaments of chemically active non-equilibrium plasma, the reaction kinetics, and the physical chemical transformations occuring in the electrical discharges, which are applied in the industry, are analysed. Some plasma chemical systems and processes related to the energy of hydrogen, with the chemical technology and with the metallurgy are described. Emphasis is given to the optimization of the energy effectiveness of these processes to obtain reducers and artificial energetic carriers. (M.C.K.)

  8. AB Blanket for Cities (for continual pleasant weather and protection from chemical, biological and radioactive weapons)

    CERN Document Server

    Bolonkin, Alexander

    2009-01-01

    In a series of previous articles (see references) the author offered to cover a city or other important large installations or subregions by a transparent thin film supported by a small additional air overpressure under the form of an AB Dome. The building of a gigantic inflatable AB Dome over an empty flat surface is not difficult. However, if we want to cover a city, garden, forest or other obstacle course we cannot easily deploy the thin film over building or trees. In this article is suggested a new method which solves this problem. The idea is to design a double film blanket filled by light gas (for example, methane, hydrogen, or helium). Sections of this AB Blanket are lighter then air and fly in atmosphere. They can be made on a flat area (serving as an assembly area) and delivered by dirigible or helicopter to station at altitude over the city. Here they connect to the already assembled AB Blanket subassemblies, cover the city in an AB Dome and protect it from bad weather, chemical, biological and rad...

  9. Efficiency and resistance of the artificial oxalate protection treatment on marble against chemical weathering

    Energy Technology Data Exchange (ETDEWEB)

    Doherty, B. [Dipartimento di Chimica, Universita degli Studi di Perugia, via Elce di Sotto, 8, I-60123 Perugia (Italy); Pamplona, M. [Centro de Petrologia e Geoquimica do Instituto Superior Tecnico Universidade Tecnica de Lisboa, Avenida Rovisco Pais, 1049-001 Lisbon (Portugal); Selvaggi, R. [Dipartimento di Chimica, Universita degli Studi di Perugia, via Elce di Sotto, 8, I-60123 Perugia (Italy); Miliani, C. [Istituto CNR di Scienze e Tecnologie Molecolari (ISTM), Dipartimento di Chimica, Universita degli Studi di Perugia, via Elce di Sotto, 8, I-60123 Perugia (Italy)]. E-mail: miliani@thch.unipg.it; Matteini, M. [CNR Istituto, Conservazione e Valorizzazione dei Beni Culturali (ICVBC), Via Madonna del Piano, 10, Edifico C-50019, Florence (Italy); Sgamellotti, A. [Dipartimento di Chimica, Universita degli Studi di Perugia, via Elce di Sotto, 8, I-60123 Perugia (Italy); Istituto CNR di Scienze e Tecnologie Molecolari (ISTM), Dipartimento di Chimica, Universita degli Studi di Perugia, via Elce di Sotto, 8, I-60123 Perugia (Italy); Brunetti, B. [Dipartimento di Chimica, Universita degli Studi di Perugia, via Elce di Sotto, 8, I-60123 Perugia (Italy)

    2007-03-15

    The artificial oxalate protection method was analyzed in laboratory experiments in order to achieve an optimum treatment application and concentration giving rise to its most effective protective nature. Spectroscopic (Fourier transform infrared, Micro-Raman and UV-vis colorimetry), microscopic (scanning electron microscope) and contact-angle analyses were carried out to characterize Carrara marble samples before and after application of the treatment to validate its efficiency. The resistance effects against chemical weathering were subsequently observed in a lab-controlled weak acid rain experiment. An acid spray at pH 5.5, representative of normal rain was used to provoke degrade of natural marble, marble treated with the artificial oxalate protective at concentrations of 0.4 and 5% and marble treated with a commercial organic silicon product. Run-off solutions sampled at timely intervals were tested for any change in pH followed by ion chromatography measurements for the presence of calcium ions in solution. The chromatography results of the oxalate treatment applied at a 5% concentration are analogous to an organic commercial product indicating its validity as a method for the conservation of carbonate substrates conferring protection to stone materials against acid environments.

  10. Weather Types, temperature and relief relationship in the Iberian Peninsula: A regional adiabatic processes under directional weather types

    Science.gov (United States)

    Peña Angulo, Dhais; Trigo, Ricardo; Cortesi, Nicola; Gonzalez-Hidalgo, Jose Carlos

    2016-04-01

    We have analyzed at monthly scale the spatial distribution of Pearson correlation between monthly mean of maximum (Tmax) and minimum (Tmin) temperatures with weather types (WTs) in the Iberian Peninsula (IP), represent them in a high spatial resolution grid (10km x 10km) from MOTEDAS dataset (Gonzalez-Hidalgo et al., 2015a). The WT classification was that developed by Jenkinson and Collison, adapted to the Iberian Peninsula by Trigo and DaCamara, using Sea Level Pressure data from NCAR/NCEP Reanalysis dataset (period 1951-2010). The spatial distribution of Pearson correlations shows a clear zonal gradient in Tmax under the zonal advection produced in westerly (W) and easterly (E) flows, with negative correlation in the coastland where the air mass come from but positive correlation to the inland areas. The same is true under North-West (NW), North-East (NE), South-West (SW) and South-East (SE) WTs. These spatial gradients are coherent with the spatial distribution of the main mountain chain and offer an example of regional adiabatic phenomena that affect the entire IP (Peña-Angulo et al., 2015b). These spatial gradients have not been observed in Tmin. We suggest that Tmin values are less sensitive to changes in Sea Level Pressure and more related to local factors. These directional WT present a monthly frequency over 10 days and could be a valuable tool for downscaling processes. González-Hidalgo J.C., Peña-Angulo D., Brunetti M., Cortesi, C. (2015a): MOTEDAS: a new monthly temperature database for mainland Spain and the trend in temperature (1951-2010). International Journal of Climatology 31, 715-731. DOI: 10.1002/joc.4298 Peña-Angulo, D., Trigo, R., Cortesi, C., González-Hidalgo, J.C. (2015b): The influence of weather types on the monthly average maximum and minimum temperatures in the Iberian Peninsula. Submitted to Hydrology and Earth System Sciences.

  11. Shenandoah National Park Phenology Project-Weather data collection, description, and processing

    Science.gov (United States)

    Jones, John W.; Aiello, Danielle P.; Osborne, Jesse D.

    2010-01-01

    The weather data described in this document are being collected as part of a U.S. Geological Survey (USGS) study of changes in Shenandoah National Park (SNP) landscape phenology (Jones and Osbourne, 2008). Phenology is the study of the timing of biological events, such as annual plant flowering and seasonal bird migration. These events are partially driven by changes in temperature and precipitation; therefore, phenology studies how these events may reflect changes in climate. Landscape phenology is the study of changes in biological events over broad areas and assemblages of vegetation. To study climate-change relations over broad areas (at landscape scale), the timing and amount of annual tree leaf emergence, maximum foliage, and leaf fall for forested areas are of interest. To better link vegetation changes with climate, weather data are necessary. This report documents weather-station data collection and processing procedures used in the Shenandoah National Park Phenology Project.

  12. Natural weathering in dry disposed ash dump: Insight from chemical, mineralogical and geochemical analysis of fresh and unsaturated drilled cores.

    Science.gov (United States)

    Akinyemi, S A; Akinlua, A; Gitari, W M; Khuse, N; Eze, P; Akinyeye, R O; Petrik, L F

    2012-07-15

    Some existing alternative applications of coal fly ash such as cement manufacturing; road construction; landfill; and concrete and waste stabilisation use fresh ash directly collected from coal-fired power generating stations. Thus, if the rate of usage continues, the demand for fresh ash for various applications will exceed supply and use of weathered dry disposed ash will become necessary alternative. As a result it's imperative to understand the chemistry and pH behaviour of some metals inherent in dry disposed fly ash. The bulk chemical composition as determined by XRF analysis showed that SiO2, Al2O3 and Fe2O3 were the major oxides in fresh ash and unsaturated weathered ashes. The unsaturated weathered ashes are relatively depleted in CaO, Fe2O3, TiO2, SiO2, Na2O and P2O5 due to dissolution and hydrolysis caused by chemical interaction with ingressing CO2 from the atmosphere and infiltrating rain water. Observed accumulations of Fe2O3, TiO2, CaO, K2O, Na2O and SO3 and Zn, Zr, Sr, Pb, Ni, Cr and Co in the lower layers indicate progressive downward movement through the ash dump though at a slow rate. The bulk mineralogy of unsaturated weathered dry disposed ash, as determined by XRD analysis, revealed quartz and mullite as the major crystalline phases; while anorthite, hematite, enstatite, lime, calcite, and mica were present as minor mineral phases. Pore water chemistry revealed a low concentration of readily soluble metals in unsaturated weathered ashes in comparison with fresh ash, which shows high leachability. This suggests that over time the precipitation of transient minor secondary mineral phases; such as calcite and mica might retard residual metal release from unsaturated weathered ash. Chloride and sulphate species of the water soluble extracts of weathered ash are at equilibrium with Na+ and K+; these demonstrate progressive leaching over time and become supersaturated at the base of unsaturated weathered ash. This suggests that the ash dump does not

  13. Chemical production processes and systems

    Science.gov (United States)

    Holladay, Johnathan E; Muzatko, Danielle S; White, James F; Zacher, Alan H

    2015-04-21

    Hydrogenolysis systems are provided that can include a reactor housing an Ru-comprising hydrogenolysis catalyst and wherein the contents of the reactor is maintained at a neutral or acidic pH. Reactant reservoirs within the system can include a polyhydric alcohol compound and a base, wherein a weight ratio of the base to the compound is less than 0.05. Systems also include the product reservoir comprising a hydrogenolyzed polyhydric alcohol compound and salts of organic acids, and wherein the moles of base are substantially equivalent to the moles of salts or organic acids. Processes are provided that can include an Ru-comprising catalyst within a mixture having a neutral or acidic pH. A weight ratio of the base to the compound can be between 0.01 and 0.05 during exposing.

  14. Chemical production processes and systems

    Science.gov (United States)

    Holladay, Johnathan E.; Muzatko, Danielle S.; White, James F.; Zacher, Alan H.

    2014-06-17

    Hydrogenolysis systems are provided that can include a reactor housing an Ru-comprising hydrogenolysis catalyst and wherein the contents of the reactor is maintained at a neutral or acidic pH. Reactant reservoirs within the system can include a polyhydric alcohol compound and a base, wherein a weight ratio of the base to the compound is less than 0.05. Systems also include the product reservoir comprising a hydrogenolyzed polyhydric alcohol compound and salts of organic acids, and wherein the moles of base are substantially equivalent to the moles of salts or organic acids. Processes are provided that can include an Ru-comprising catalyst within a mixture having a neutral or acidic pH. A weight ratio of the base to the compound can be between 0.01 and 0.05 during exposing.

  15. Chemical Processing Department monthly report, June 1958

    Energy Technology Data Exchange (ETDEWEB)

    1958-07-22

    This report for June 1958, from the Chemical Processing Department at HAPO, discusses the following: Production operation; Purex and Redox operation; Finished products operation; maintenance; Financial operations; facilities engineering; research; and employee relations.

  16. Molecular Thermodynamics for Chemical Process Design

    Science.gov (United States)

    Prausnitz, J. M.

    1976-01-01

    Discusses that aspect of thermodynamics which is particularly important in chemical process design: the calculation of the equilibrium properties of fluid mixtures, especially as required in phase-separation operations. (MLH)

  17. Chemical Processing Department monthly report, October 1963

    Energy Technology Data Exchange (ETDEWEB)

    Young, J. F.; Johnson, W. E.; Reinker, P. H.; Warren, J. H.; McCullugh, R. W.; Harmon, M. K.; Gartin, W. J.; LaFollette, T. G.; Shaw, H. P.; Frank, W. S.; Grim, K. G.; Warren, J. H.

    1963-11-21

    This report, for October 1963 from the Chemical Processing Department at HAPO, discusses the following: Production operation; Purex and Redox operation; Finished products operation; maintenance; Financial operations; facilities engineering; research; employee relations; weapons manufacturing operation; and safety and security.

  18. Chemical Processing Department monthly report, October 1962

    Energy Technology Data Exchange (ETDEWEB)

    1962-11-21

    This report, from the Chemical Processing Department at HAPO, for October, 1962 discusses the following: Production operation; Purex and Redox operation; Finished products operation; maintenance; Financial operations; facilities engineering; research; employee relations; and weapons manufacturing operation.

  19. Chemical Processing Department monthly report, February 1963

    Energy Technology Data Exchange (ETDEWEB)

    1963-03-21

    This report, for February 1963 from the Chemical Processing Department at HAPO, discusses the following: Production operation; Purex and Redox operation; Finished products operation; maintenance; Financial operations; facilities engineering; research; employee relations; weapons manufacturing operation; and safety and security.

  20. Chemical Processing Department monthly report, October 1965

    Energy Technology Data Exchange (ETDEWEB)

    1965-11-22

    This report, from the Chemical Processing Department at HAPO, discusses the following: production operation; purex and redox operation; finished products operation; maintenance; financial operations; facilities engineering; research; and employee relations.

  1. Iron-sulfur mineralogy of Mars - Magmatic evolution and chemical weathering products

    Science.gov (United States)

    Burns, Roger G.; Fisher, Duncan S.

    1990-01-01

    Models are developed for the magmatic evolution and the oxidative weathering of sulfide minerals on Mars, based on petrogenetic associations among komatiitic rock types, Viking geochemical data, SNC meteorites, and terrestrial Fi-Ni deposits. The weathering model was tested by exposing komatiitic pyrrhotites and olivines to sulfuric acid solutions, with or without dissolved ferric iron, and identifying the reaction products by Moessbauer spectroscopy. The results suggest that, on Mars, acidic groundwater has induced oxidative weathering of pyrrhotite, yielding FeS2 and then FeOOH.

  2. Chemical Processing Department monthly report, November 1956

    Energy Technology Data Exchange (ETDEWEB)

    1956-12-21

    The November 1956 monthly report for the Chemical Processing Department of Hanford Atomic Products Operation includes information regarding research and engineering efforts with respect to the Purex and Redox process technology. Also discussed was the production operation, finished product operation, power and general maintenance, financial operation, engineering and research operations, and employee operations. (MB)

  3. Chemical Processing Department monthly report, May 1958

    Energy Technology Data Exchange (ETDEWEB)

    1958-06-20

    The May, 1956 monthly report for the Chemical Processing Department of Hanford Atomic Products Operation includes information regarding research and engineering efforts with respect to the Purex and Redox process technology. Also discussed is the production operation, finished products operation, power and general maintenance, financial operation, engineering and research operations, and employee operations. (MB)

  4. Chemical Processing Department monthly report, July 1958

    Energy Technology Data Exchange (ETDEWEB)

    1958-08-22

    The July, 1958 monthly report for the Chemical Processing Department of the Hanford Atomic Products Operation includes information regarding research and engineering efforts with respect to the Purex and Redox process technology. Also discussed is the production operation, finished product operation, power and general maintenance, financial operation, engineering and research operations, and employee operation. (MB)

  5. Chemical Processing Department monthly report, May 1957

    Energy Technology Data Exchange (ETDEWEB)

    1957-06-21

    The May, 1957 monthly report for the Chemical Processing Department of the Hanford Atomic Products Operation includes information regarding research and engineering efforts with respect to the Purex and Redox process technology. Also discussed is the production operation, finished product operation, power and general maintenance, financial operation, engineering and research operations, and employee operation.(MB)

  6. The role of reaction affinity and secondary minerals in regulating chemical weathering rates at the Santa Cruz Soil Chronosequence, California

    Science.gov (United States)

    Maher, K.; Steefel, Carl; White, A.F.; Stonestrom, D.A.

    2009-01-01

    In order to explore the reasons for the apparent discrepancy between laboratory and field weathering rates and to determine the extent to which weathering rates are controlled by the approach to thermodynamic equilibrium, secondary mineral precipitation, and flow rates, a multicomponent reactive transport model (CrunchFlow) was used to interpret soil profile development and mineral precipitation and dissolution rates at the 226 ka Marine Terrace Chronosequence near Santa Cruz, CA. Aqueous compositions, fluid chemistry, transport, and mineral abundances are well characterized [White A. F., Schulz M. S., Vivit D. V., Blum A., Stonestrom D. A. and Anderson S. P. (2008) Chemical weathering of a Marine Terrace Chronosequence, Santa Cruz, California. I: interpreting the long-term controls on chemical weathering based on spatial and temporal element and mineral distributions. Geochim. Cosmochim. Acta 72 (1), 36-68] and were used to constrain the reaction rates for the weathering and precipitating minerals in the reactive transport modeling. When primary mineral weathering rates are calculated with either of two experimentally determined rate constants, the nonlinear, parallel rate law formulation of Hellmann and Tisserand [Hellmann R. and Tisserand D. (2006) Dissolution kinetics as a function of the Gibbs free energy of reaction: An experimental study based on albite feldspar. Geochim. Cosmochim. Acta 70 (2), 364-383] or the aluminum inhibition model proposed by Oelkers et al. [Oelkers E. H., Schott J. and Devidal J. L. (1994) The effect of aluminum, pH, and chemical affinity on the rates of aluminosilicate dissolution reactions. Geochim. Cosmochim. Acta 58 (9), 2011-2024], modeling results are consistent with field-scale observations when independently constrained clay precipitation rates are accounted for. Experimental and field rates, therefore, can be reconciled at the Santa Cruz site. Additionally, observed maximum clay abundances in the argillic horizons occur at

  7. Impact of weathering on chemical and morphological changes in stabilized polymers

    Czech Academy of Sciences Publication Activity Database

    Pospíšil, Jan; Pilař, Jan; Billingham, N. C.; Marek, Antonín; Kruliš, Zdeněk; Nešpůrek, Stanislav; Habicher, W. D.

    Karlsruhe : Gesellschaft für Umweltsimulation, 2004, s. 411-421. ISBN 3-9808382-5-0. [European Weathering Symposium on Natural and Artificial Ageing of Polymers /1./. Prague (CZ), 25.09.2004-26.09.2004] R&D Projects: GA ČR GA203/02/1243; GA MŠk ME 543 Institutional research plan: CEZ:AV0Z4050913 Keywords : photo oxidation * weathering * stabilizers Subject RIV: CD - Macromolecular Chemistry

  8. Process safety management for highly hazardous chemicals

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-02-01

    Purpose of this document is to assist US DOE contractors who work with threshold quantities of highly hazardous chemicals (HHCs), flammable liquids or gases, or explosives in successfully implementing the requirements of OSHA Rule for Process Safety Management of Highly Hazardous Chemicals (29 CFR 1910.119). Purpose of this rule is to prevent releases of HHCs that have the potential to cause catastrophic fires, explosions, or toxic exposures.

  9. Deducing Weathering Processes Using Silicon Isotopes in the Ganges Alluvial Plain, India

    Science.gov (United States)

    Frings, P.; De La Rocha, C. L.; Fontorbe, G.; Chakrapani, G.; Clymans, W.; Conley, D. J.

    2014-12-01

    The Ganges Alluvial Plain ('GAP') is the sedimentary infill of the foreland basin created during Himalayan orogeny. Freshly eroded material from the Himalaya and southern cratonic tributaries is deposited into a system with long water-sediment interaction times, creating potential for further generation of river weathering fluxes. To quantify weathering processes in the GAP, 51 sites including all major tributaries were sampled in a September 2013 campaign and analysed for major and minor ions, Ge/Si ratios and δ30Si, δ13C and δ18O. Net dissolved Si (DSi) and major cation yields are 2 to 5 times lower in the GAP than the Himalaya, and at a whole basin scale approximate the global average, indicating that the plain apparently moderates the efficiency of Himalayan weathering rates. Mainstem δ30Si spans 0.81 to 1.93‰ (see figure) and gives the impression of a system buffered to moderate DSi and δ30Si. Ge/Si ratios (µmol/mol) are higher than expected in the Himalaya (>3), reflecting input of Ge-enriched water from hot springs, and decline to ~1.4 in the GAP. For the Himalayan sourced rivers, δ30Si increases with distance from the Himalayan front, and can not be explained entirely by conservative mixing with higher δ30Si peninsular and GAP streams. To a first degree, the δ30Si data suggest incorporation of Si into secondary minerals as the key fractionating process, and that this occurs both in situ during initial weathering and progressively in the GAP. Partitioning of solutes between sources is complicated in the GAP. Consistent with previous work, carbonate weathering dominates the ion fluxes, but with substantial contributions from saline/alkaline soil salts, the chlorination of wastewater and highly variable rainfall chemistry. Due to these contributions, precisely inferring the input from silicate weathering is difficult. We introduce a novel method to infer silicate-weathering rates that exploits the fractionation of Si during clay formation to account

  10. Chemicals Industry New Process Chemistry Roadmap

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2000-08-01

    The Materials Technology I workshop was held in November 1998 to address future research needs for materials technology that will support the chemical industry. Areas covered included disassembly, recovery, reuse and renewable technology; new materials; and materials measurement and characterization. The Materials Technology II workshop was held in September 1999 and covered additives, modeling and prediction and an additional segment on new materials. Materials Technology Institute (MTI) for the Chemical Process Industries, Inc. and Air Products & Chemicals lead the workshops. The Materials Technology Roadmap presents the results from both workshops.

  11. Processing of 3D Weather Radar Data with Application for Assimilation in the NWP Model

    OpenAIRE

    Ośródka Katarzyna; Szturc Jan; Jakubiak Bogumił; Jurczyk Anna

    2014-01-01

    The paper is focused on the processing of 3D weather radar data to minimize the impact of a number of errors from different sources, both meteorological and non-meteorological. The data is also quantitatively characterized in terms of its quality. A set of dedicated algorithms based on analysis of the reflectivity field pattern is described. All the developed algorithms were tested on data from the Polish radar network POLRAD. Quality control plays a key role in avoiding the introduction of i...

  12. Impact of sediment-seawater cation exchange on Himalayan chemical weathering fluxes

    Science.gov (United States)

    Lupker, Maarten; France-Lanord, Christian; Lartiges, Bruno

    2016-08-01

    Continental-scale chemical weathering budgets are commonly assessed based on the flux of dissolved elements carried by large rivers to the oceans. However, the interaction between sediments and seawater in estuaries can lead to additional cation exchange fluxes that have been very poorly constrained so far. We constrained the magnitude of cation exchange fluxes from the Ganga-Brahmaputra river system based on cation exchange capacity (CEC) measurements of riverine sediments. CEC values of sediments are variable throughout the river water column as a result of hydrological sorting of minerals with depth that control grain sizes and surface area. The average CEC of the integrated sediment load of the Ganga-Brahmaputra is estimated ca. 6.5 meq 100 g-1. The cationic charge of sediments in the river is dominated by bivalent ions Ca2+ (76 %) and Mg2+ (16 %) followed by monovalent K+ (6 %) and Na+ (2 %), and the relative proportion of these ions is constant among all samples and both rivers. Assuming a total exchange of exchangeable Ca2+ for marine Na+ yields a maximal additional Ca2+ flux of 28 × 109 mol yr-1 of calcium to the ocean, which represents an increase of ca. 6 % of the actual river dissolved Ca2+ flux. In the more likely event that only a fraction of the adsorbed riverine Ca2+ is exchanged, not only for marine Na+ but also Mg2+ and K+, estuarine cation exchange for the Ganga-Brahmaputra is responsible for an additional Ca2+ flux of 23 × 109 mol yr-1, while ca. 27 × 109 mol yr-1 of Na+, 8 × 109 mol yr-1 of Mg2+ and 4 × 109 mol yr-1 of K+ are re-absorbed in the estuaries. This represents an additional riverine Ca2+ flux to the ocean of 5 % compared to the measured dissolved flux. About 15 % of the dissolved Na+ flux, 8 % of the dissolved K+ flux and 4 % of the Mg2+ are reabsorbed by the sediments in the estuaries. The impact of estuarine sediment-seawater cation exchange appears to be limited when evaluated in the context of the long-term carbon cycle and

  13. Nanomorphology of Itokawa regolith particles: Application to space-weathering processes affecting the Itokawa asteroid

    Science.gov (United States)

    Matsumoto, Toru; Tsuchiyama, Akira; Uesugi, Kentaro; Nakano, Tsukasa; Uesugi, Masayuki; Matsuno, Junya; Nagano, Takashi; Shimada, Akira; Takeuchi, Akihisa; Suzuki, Yoshio; Nakamura, Tomoki; Nakamura, Michihiko; Gucsik, Arnold; Nagaki, Keita; Sakaiya, Tatsuhiro; Kondo, Tadashi

    2016-08-01

    The morphological properties of 26 regolith particles from asteroid Itokawa were observed using scanning electron microscopes in combination with an investigation of their three-dimensional shapes obtained through X-ray microtomography. Surface observations of a cross section of the LL5 chondrite, and of crystals of olivine and pyroxene, were also performed for comparison. Some Itokawa particles have surfaces corresponding to walls of microdruses in the LL chondrite, where concentric polygonal steps develop and euhedral or subhedral grains exist. These formed through vapor growth owing to thermal annealing, which might have been caused by thermal metamorphism or shock-induced heating in Itokawa's parent body. Most of the Itokawa particles have more or less fractured surfaces, indicating that they were formed by disaggregation, probably caused by impacts. Itokawa particles with angular and rounded edges observed in computed tomography images are associated with surfaces exhibiting clear and faint structures, respectively. These surfaces can be interpreted by invoking different degrees of abrasion after regolith formation. A possible mechanism for the abrasion process is grain migration caused by impact-driven seismic waves. Space-weathered rims with blisters are distributed heterogeneously across the Itokawa regolith particles. This heterogeneous distribution can be explained by particle motion and fracturing, combined with solar-wind irradiation of the particle surfaces. The regolith activity-including grain motion, fracturing, and abrasion-might effectively act as refreshing process of Itokawa particles against space-weathered rim formation. The space-weathering processes affecting Itokawa would have developed simultaneously with space-weathered rim formation and regolith particle refreshment.

  14. Personal Insights and Anecdotes about the Weatherization Assistance Program Process Field Study

    Energy Technology Data Exchange (ETDEWEB)

    Treitler, Inga [Anthropology Imagination, Inc., Knoxville, TN (United States)

    2014-09-01

    The present report is based on the research conducted for the Process Field Study between March and September 2011. The Process Field Study documents how Weatherization Assistance Program (WAP) services were delivered to clients, and the quality with which those services were delivered. The assessments were conducted by visiting 19 agencies in 19 states around the country interviewing agency managers, staff, and contractors; observing program intake along, with 43 audits, 45 measure installation and 37 final inspections; and conducting debriefing interviews with clients and weatherization staff following the observation of service delivery. In this report, we turn to detailed observations of a few field interactions. The client stories from our observations illustrate some of the ways clients and crew interact to build the success of the program, but shows there will always be unanticipated obstacles to building trust and getting the program to the public. Stories of staff and crew career paths indicate that weatherization technology and techniques are being learned and used by technicians out of the new home construction industry and that their new knowledge provides them with technical tools and methods that many hope to take back into the construction industry if and when they return. This report is organized according to the four stages of weatherization: intake, audit, installation, and inspection. It contributes to our understanding of the area where policy, environment, culture, and individual decisions influence social innovation. The anecdotes reveal the realities of implementing programs for the benefit of the greater good at minimal cost and sacrifice in times of ever restricting budgets. As the authors revisited their field notes and compiled memorable narratives to communicate the essence of the weatherization experience, they identified three key takeaways that summarize the major issues. First, in WAP as in all services there will always be

  15. Geochemical study of boron isotopes in the process of loess weathering

    Institute of Scientific and Technical Information of China (English)

    赵志琦; 刘丛强; 肖应凯; 郎赟超

    2003-01-01

    In this paper the boron contents and boron isotopic composition of acid-soluble phases in loess and paleosol samples are determined for the first time. The boron contents of acid-soluble phases in the Luochuan loess section (S0 -S2) vary within the range of (0.8-2.7)×10-6 and theirδ11B values vary from -1.8‰ to +18.6‰, mostly within the range of 0-+10‰. The boron contents andδ11B values of paleosol layers are higher than those of loess layers, especially in the loess layer S1. Varying chemical weathering intensity and loess adsorption capability are the main factors leading to the variations of boron contents and δ11B values of acid-soluble phases in the loess section. The variation of chemical weathering intensity in response to the variation of climatic conditions seems to be the main factor leading to the variations of boron contents andδ11B values of acid-soluble phases in the loess section.

  16. Chemical Processes in Astrophysical Radiation Fields

    International Nuclear Information System (INIS)

    The effects of stimulated photon emission on chemical processes in a radiation field are considered and their influence on the chemistry of the early universe and other astrophysical environments is investigated. Spontaneous and stimulated radiative attachment rate coefficients for H(-), Li(-) and C(-) are presented

  17. Safety Considerations in the Chemical Process Industries

    Science.gov (United States)

    Englund, Stanley M.

    There is an increased emphasis on chemical process safety as a result of highly publicized accidents. Public awareness of these accidents has provided a driving force for industry to improve its safety record. There has been an increasing amount of government regulation.

  18. A Novel Chemical Nitrate Destruction Process

    Energy Technology Data Exchange (ETDEWEB)

    Dziewinski, J.; Marczak, S.

    1999-03-01

    Nitrates represent one of the most significant pollutant discharged to the Baltic Sea by the Sliiamae hydrometallurgical plant. This article contains a brief overview of the existing nitrate destruction technologies followed by the description of a new process developed by the authors. The new chemical process for nitrate destruction is cost effective and simple to operate. It converts the nitrate to nitrogen gas which goes to the atmosphere.

  19. Desulphurization of exhaust gases in chemical processes

    Energy Technology Data Exchange (ETDEWEB)

    Asperger, K.; Wischnewski, W.

    1981-01-01

    The sulfur content of exhaust gases can be reduced by: desulphurization of fuels; modification of processes; or treatment of resultant gases. In this paper a few selected examples from the chemical industry in the German Democratic Republic are presented. Using modified processes and treating the resultant gases, the sulphuric content of exhaust gases is effectively reduced. Methods to reduce the sulfur content of exhaust gases are described in the field of production of: sulphuric acid; viscose; fertilizers; and paraffin.

  20. Synthesis and optimization of integrated chemical processes

    Energy Technology Data Exchange (ETDEWEB)

    Barton, Paul I.; Evans, Lawrence B.

    2002-04-26

    This is the final technical report for the project titled ''Synthesis and optimization of integrated chemical processes''. Progress is reported on novel algorithms for the computation of all heteroazeotropic compositions present in complex liquid mixtures; the design of novel flexible azeotropic separation processes using middle vessel batch distillation columns; and theory and algorithms for sensitivity analysis and numerical optimization of hybrid discrete/continuous dynamic systems.

  1. Processing of 3D Weather Radar Data with Application for Assimilation in the NWP Model

    Directory of Open Access Journals (Sweden)

    Ośródka Katarzyna

    2014-09-01

    Full Text Available The paper is focused on the processing of 3D weather radar data to minimize the impact of a number of errors from different sources, both meteorological and non-meteorological. The data is also quantitatively characterized in terms of its quality. A set of dedicated algorithms based on analysis of the reflectivity field pattern is described. All the developed algorithms were tested on data from the Polish radar network POLRAD. Quality control plays a key role in avoiding the introduction of incorrect information into applications using radar data. One of the quality control methods is radar data assimilation in numerical weather prediction models to estimate initial conditions of the atmosphere. The study shows an experiment with quality controlled radar data assimilation in the COAMPS model using the ensemble Kalman filter technique. The analysis proved the potential of radar data for such applications; however, further investigations will be indispensable.

  2. NATO Advanced Research Workshop on The Chemistry of Weathering

    CERN Document Server

    1985-01-01

    Several important developments in our understanding of the chemistry of weathering have occurred in the last few years: 1. There has been a major breakthrough in our understanding of the mechanisms controlling the kinetics of sil icate dissolution, and there have been major advances in computer modeling of weathering processes. 2. There has been a growing recognition of the importance of organic solutes in the weathering process, and hence of the inter-relationships between mineral weathering and the terrestrial ecosystem. 3. The impact of acid deposition ("acid rain") has been widely recognized. The processes by which acid deposition is neutral ized are closely related to the processes of normal chemical weathering; an understanding of the chemistry of weathering is thus essential for predicting the effects of acid deposition. 4. More high-qual ity data have become available on the chemical dynamics of smal I watersheds and large river systems, which represent the integrated effects of chemical weathering.

  3. Effects of Climate on Long-term Rates of Physical Erosion and Chemical Weathering: Evidence from Cosmogenic Nuclides and Geochemical Mass Balance

    Science.gov (United States)

    Kirchner, J. W.; Riebe, C. S.; Ferrier, K. L.; Finkel, R. C.

    2004-12-01

    Cosmogenic nuclides such as 10Be and 26Al have recently become important tools for measuring long-term denudation rates. We have recently shown how cosmogenic nuclide measurements of denudation fluxes can be partitioned into their physical and chemical components, using the enrichment of insoluble tracers in regolith relative to its parent rock. We used these methods to measure long-term rates of physical erosion and chemical weathering for 42 sites, encompassing widely varying climates and denudation rates. Across these sites, mean annual temperatures vary from 2 to 25 ° C, average annual precipitation spans a 20-fold range (from 22 to 420 cm/yr), and denudation rates vary by 32-fold (from 23 to 755 t km-2 yr-2). Our measurements show that chemical weathering rates are tightly coupled with physical erosion rates, such that the relationship between climate and chemical weathering rates may be obscured by site-to-site differences in the rate that minerals are supplied to soil by physical erosion of rock. The relative importance of chemical weathering can be quantified using the "Weathering Intensity Factor" (WIF), the ratio of the chemical weathering rate to the physical erosion rate. Over 60 percent of the variance in WIF's can be explained by a simple Arrhenius-like relationship based on mean annual temperature and average annual precipitation. The temperature-dependence of WIF is roughly half of what one would expect from laboratory measurements of activation energies for feldspar weathering and previous inter-comparisons of short-term average weathering rates from the field. Our results imply that the strength of climate change feedbacks between temperature and silicate weathering rates may be weaker than previously thought, at least in actively eroding, unglaciated granitic terrain similar to our study sites.

  4. Chemical computing with reaction-diffusion processes.

    Science.gov (United States)

    Gorecki, J; Gizynski, K; Guzowski, J; Gorecka, J N; Garstecki, P; Gruenert, G; Dittrich, P

    2015-07-28

    Chemical reactions are responsible for information processing in living organisms. It is believed that the basic features of biological computing activity are reflected by a reaction-diffusion medium. We illustrate the ideas of chemical information processing considering the Belousov-Zhabotinsky (BZ) reaction and its photosensitive variant. The computational universality of information processing is demonstrated. For different methods of information coding constructions of the simplest signal processing devices are described. The function performed by a particular device is determined by the geometrical structure of oscillatory (or of excitable) and non-excitable regions of the medium. In a living organism, the brain is created as a self-grown structure of interacting nonlinear elements and reaches its functionality as the result of learning. We discuss whether such a strategy can be adopted for generation of chemical information processing devices. Recent studies have shown that lipid-covered droplets containing solution of reagents of BZ reaction can be transported by a flowing oil. Therefore, structures of droplets can be spontaneously formed at specific non-equilibrium conditions, for example forced by flows in a microfluidic reactor. We describe how to introduce information to a droplet structure, track the information flow inside it and optimize medium evolution to achieve the maximum reliability. Applications of droplet structures for classification tasks are discussed. PMID:26078345

  5. Idaho Chemical Processing Plant product denitrator upgrade

    International Nuclear Information System (INIS)

    The uranium product denitrator at the Idaho Chemical Processing Plant has had serious operating problems since 1970, including inadequate contamintion control, fluidized bed caking, frequent bed heater failure, product overflow plugging, and poor feed control. These problems were minimized through selective redesign and upgrade of the process equipment as part of a process upgrade program completed in March 1981. Following startup and testing of the rebuilt product denitrator, 1044 kg of enriched uranium was processed in three weeks while demonstrating greater reliability, ease of operation, and improved contamination control. To maximize personnel safety in the future, the denitrator vessel should be made critically safe by geometry and process instrumentation isolated from the process for semi-remote operation

  6. Supporting chemical process design under uncertainty

    Directory of Open Access Journals (Sweden)

    A. Wechsung

    2010-09-01

    Full Text Available A major challenge in chemical process design is to make design decisions based on partly incomplete or imperfect design input data. Still, process engineers are expected to design safe, dependable and cost-efficient processes under these conditions. The complexity of typical process models limits intuitive engineering estimates to judge the impact of uncertain parameters on the proposed design. In this work, an approach to quantify the effect of uncertainty on a process design in order to enhance comparisons among different designs is presented. To facilitate automation, a novel relaxation-based heuristic to differentiate between numerical and physical infeasibility when simulations do not converge is introduced. It is shown how this methodology yields more details about limitations of a studied process design.

  7. Energy conversion technology by chemical processes

    Energy Technology Data Exchange (ETDEWEB)

    Oh, I.W.; Yoon, K.S.; Cho, B.W. [Korea Inst. of Science and Technology, Seoul (Korea, Republic of)] [and others

    1996-12-01

    The sharp increase in energy usage according to the industry development has resulted in deficiency of energy resources and severe pollution problems. Therefore, development of the effective way of energy usage and energy resources of low pollution is needed. Development of the energy conversion technology by chemical processes is also indispensable, which will replace the pollutant-producing and inefficient mechanical energy conversion technologies. Energy conversion technology by chemical processes directly converts chemical energy to electrical one, or converts heat energy to chemical one followed by heat storage. The technology includes batteries, fuel cells, and energy storage system. The are still many problems on performance, safety, and manufacturing of the secondary battery which is highly demanded in electronics, communication, and computer industries. To overcome these problems, key components such as carbon electrode, metal oxide electrode, and solid polymer electrolyte are developed in this study, followed by the fabrication of the lithium secondary battery. Polymer electrolyte fuel cell, as an advanced power generating apparatus with high efficiency, no pollution, and no noise, has many applications such as zero-emission vehicles, on-site power plants, and military purposes. After fabricating the cell components and operating the single cells, the fundamental technologies in polymer electrolyte fuel cell are established in this study. Energy storage technology provides the safe and regular heat energy, irrespective of the change of the heat energy sources, adjusts time gap between consumption and supply, and upgrades and concentrates low grade heat energy. In this study, useful chemical reactions for efficient storage and transport are investigated and the chemical heat storage technology are developed. (author) 41 refs., 90 figs., 20 tabs.

  8. Radionuclide Incorporation in Secondary Crystalline Minerals Resulting from Chemical Weathering of Selected Waste Glasses: Progress Report: Task kd.5b

    Energy Technology Data Exchange (ETDEWEB)

    Mattigod, Shas V.; Serne, R. Jeffrey; Legore, Virginia L.; Parker, Kent E.; Orr, Robert D.; McCready, David E.; Young, James S.

    2003-09-29

    Experiments were conducted by Pacific Northwest National Laboratory to evaluate potential incorporation of radionuclides in secondary mineral phases that form from weathering vitrified nuclear waste glasses. These experiments were conducted as part of the Immobilized Low-Activity Waste-Performance Assessment (ILAW-PA) to generate data on radionuclide mobilization and transport in a near-field environment of disposed vitrified wastes. The results of these experiments demonstrated that radionuclide sequestration can be significantly enhanced by promoting the formation of cage structured minerals such as sodalite from weathering glasses. These results have important implications regarding radionuclide sequestration/mobilization aspects that are not currently accounted for in the ILAW PA. Additional studies are required to confirm the results and to develop an improved understanding of the mechanisms of sequestration of radionuclides into the secondary and tertiary weathering products of the ILAW glass to help refine how contaminants are released from the near-field disposal region out into the accessible environment. Of particular interest is to determine whether the contaminants remain sequestered in the glass weathering products for hundreds to thousands of years. If the sequestration can be shown to continue for long periods, another immobilization process can be added to the PA analysis and predicted risks should be lower than past predictions.

  9. Radionuclide Incorporation in Secondary Crystalline Minerals Resulting from Chemical Weathering of Selected Waste Glasses: Progress Report: Task kd.5b

    International Nuclear Information System (INIS)

    Experiments were conducted by Pacific Northwest National Laboratory to evaluate potential incorporation of radionuclides in secondary mineral phases that form from weathering vitrified nuclear waste glasses. These experiments were conducted as part of the Immobilized Low-Activity Waste-Performance Assessment (ILAW-PA) to generate data on radionuclide mobilization and transport in a near-field environment of disposed vitrified wastes. The results of these experiments demonstrated that radionuclide sequestration can be significantly enhanced by promoting the formation of cage structured minerals such as sodalite from weathering glasses. These results have important implications regarding radionuclide sequestration/mobilization aspects that are not currently accounted for in the ILAW PA. Additional studies are required to confirm the results and to develop an improved understanding of the mechanisms of sequestration of radionuclides into the secondary and tertiary weathering products o f the ILAW glass to help refine how contaminants are released from the near-field disposal region out into the accessible environment. Of particular interest is to determine whether the contaminants remain sequestered in the glass weathering products for hundreds to thousands of years. If the sequestration can be shown to continue for long periods, another immobilization process can be added to the PA analysis and predicted risks should be lower than past predictions

  10. Chemical cleaning processes - present and future

    International Nuclear Information System (INIS)

    Corrosion products and impurities can accumulate in the secondary side of steam generators causing accelerated corrosion, steam flow disruption and heat transfer loss. Traditionally, chemical cleaning processes have been performed using multi-step processes that employ relatively concentrated reagents (e.g. EPRI-SGOG, 10-20 wt.%), that are applied at elevated temperatures. The use of such reagents dictates the use of large and relatively complex reagent handling systems for both reagent preparation and disposal. The significant duration and cost of each chemical clean has dictated that these cleaning processes are only applied on a remedial basis. An assessment of existing technology was carried out and improvements to the EPRI-SGOG processes are being developed. Results of these assessments are reported. Advanced processes are being developed by Atomic Energy of Canada Limited that use lower concentrations of reagents, require shorter application times and generate lower amounts of waste. This technology can be used on a preventive basis to keep steam generators clean. Included are: A dilute regenerative process that is applied during shutdown. The dilute reagent is continuously recirculated and regenerated during the cleaning process, resulting in shorter application times using modular and portable equipment. The low reagent concentration results in a significantly reduced waste volume. For deposits containing both magnetite and copper a pseudo one-step process (using the same base electrolyte and pH) is used with alternate addition of oxidizing or reducing agents; A dilute on-line process that can be used while the reactor is operating. Such a process would be used on a periodic basis and dislodged oxides removed by blowdown or by mechanical means; Additives that can be used to keep steam generators clean. A demonstration of this technology is currently being planned. Details of these technologies will be described. (author)

  11. Utilization of chemical looping strategy in coal gasification processes

    Institute of Scientific and Technical Information of China (English)

    Liangshih Fan; Fanxing Li; Shwetha Ramkumar

    2008-01-01

    Three chemical looping gasification processes, i. e. Syngas Chemical Looping (SCL) process, Coal Direct Chemical Looping (CDCL) process, and Calcium Looping process (CLP), are being developed at the Ohio State University (OSU). These processes utilize simple reaction schemes to convert carbonaceous fuels into products such as hydrogen, electricity, and synthetic fuels through the transformation of a highly reactive, highly recyclable chemical intermediate. In this paper, these novel chemical looping gasification processes are described and their advantages and potential challenges for commercialization are discussed.

  12. Process evaluation of the Bonneville Power Administration Residential Weatherization Pilot Program

    Energy Technology Data Exchange (ETDEWEB)

    Lerman, D.I.; Bronfman, B.H.; Tonn, B.

    1983-10-01

    An evaluation of the BPA Residential Weatherization Pilot Program is described. Data for this report were gathered at the eleven public utilities participating in the program, at the BPA area and district offices serving these utilities, and at BPA headquarters. This process evaluation of the Pilot Program documents the history of the program, outlines the implementation strategies adopted by the Pilot utilities, describes the role of the BPA area and district offices in the program, and indicates what was learned by BPA and the utilities in the period the program operated.

  13. Weak chemical weathering during the Little Ice Age recorded by lake sediments

    Institute of Scientific and Technical Information of China (English)

    JIN; Zhangdong

    2001-01-01

    Bulletin, 1999, 44 (supplement 1): 20-25.[12]Ding, Z. L., Yu, Z. W., Rutter, N. W. et al., Towards an orbital time scale for Chinese loess deposits, Quaternary Science Review, 1994,13: 39-70.[13]Duchaufour, Ph., Pedologie, Tome 1: Pedogenese et Classification, Paris-New York-Barcelone-Milan: Masson, 1983, 1-477.[14]Singer, M. J., Bowen, L. H., Verosub, K. L. et al., Mossbauer spectroscopic evidence for citrate-bicarbonate-dithionite ex-traction of maghemite from soils, Clays and Clay Minerals,1995, 43: 1-7.[15]Hunt, C. P., Singer, M. J., Kletetschka, G. et al., Effect of citrate-bicarbonate-dithionite treatment on fine-grained mag-netite and maghemite, Earth Planet. Sci. Lett., 1995, 130: 87-94.[16]Mehra, O., Jackson, M. L., Iron oxide removal from soil and clay by a dithionite-citrate system buffered with sodium bi-carbonate, Clay and Clay Minerals, 1960, 7: 317-327.[17]McKeague, J. A., Manual on soil sampling and methods of analysis, Toronto: Canadian Society of Soil Science, 1981, 1-212.[18]Kukla, G., An, Z. S., Melice, J. L. et al., Magnetic susceptibility record of Chinese loess, Transaction of Royal Society of Edinburgh, Earth Sciences, 1990, 81: 263-288.[19]Guo, Z. T., Wei, L. Y., Lu, H. Y. et al., Changes in the composition of Late Pleistocene aeolian dust and the environmental significance, Quaternary Sciences (in Chinese), 1999, 19(1): 41-48.[20]Heller, F., Liu, X. M., Liu, T. S. et al., Magnetic susceptibility of loess in China, Earth and Planetary Science Letters, 1991,103: 301-310.[21]Yang, J. D., Chen, J., An, Z. S. et al., Variations in 87Sr/86Sr Ratios of calcites in Chinese loess: A proxy for chemical weathering associated with the East Asian Summer monsoon, Palaeogeography Palaeoclimatology Palaeoecology, 2000,157: 151-159.[22]Verosub, K. L., Fine, P., Singer, M. J. et al., Pedogenesis and paleoclimate: Interpretation of the magnetic susceptibility record of Chinese loess-paleosol sequences, Geology, 1993, 21

  14. Characteristics of chemical weathering and water-rock interaction in Lake Nyos dam (Cameroon): Implications for vulnerability to failure and re-enforcement

    Science.gov (United States)

    Fantong, Wilson Y.; Kamtchueng, Brice T.; Yamaguchi, Kohei; Ueda, Akira; Issa; Ntchantcho, Romaric; Wirmvem, Mengnjo J.; Kusakabe, Minoru; Ohba, Takeshi; Zhang, Jing; Aka, Festus T.; Tanyileke, Gregory; Hell, Joseph V.

    2015-01-01

    For the first time, comprehensive study of hydrogeochemistry of water seeps, role of chemical weathering on dam failure, estimation of minimum width of dam to resist failure and simulation of changes in dissolved ions and secondary mineral was conducted on the Lake Nyos dam. The salient results and conclusions were; the dam spring water represented a mixture of 60-70% rainwater and 30-40% Lake water (from 0 to -40 m). The chemistry of the observed waters was Ca-HCO3 for rainwater, Ca-Mg-HCO3 in boreholes, and Mg-Ca-HCO3- for spring water. The relative rate at which ions dissolved in water was HCO3- > Mg2+ > Ca2+ > Na+ > SiO2 > K+ > NO3- > SO42- > Cl-. Weathering of rocks resulted in the formation of clay minerals such as kaolinite and smectite. Relative mobility of elements compared to Alumina (Al2O3) indicated that in monzonites there was a loss of CaO, Na2O, K2O, P2O5 and gain of SiO2, Fe2O3, TiO2, MnO and MgO, while in basalts there was a loss of SiO2, Fe2O3, Ca2O, NaO, MgO and gain of TiO2, K2O and P2O5. Values of chemical alteration index that ranged from 49 to 82 suggest a weak to intermediate categories of chemical weathering that occurred at a rate of 5.7 mm/year. Paired to that rate, which suggests that the dam is not vulnerable to failure at the previously thought time scale, some other processes (physical weathering, secondary mineral formation and lake overflow) can cause instant failure. Hydrostatic pressure of 1.6 GN generated by Lake water can be supported only when the width of the dam is greater than 19 m. PHREEQC-based simulation for 10 years indicates decoupling of Ca and Mg, and Na and Mg. Multidisciplinary monitoring of the dam is advocated.

  15. Geochemical study of boron isotopes in the process of loess weathering

    Institute of Scientific and Technical Information of China (English)

    ZHAO; Zhiqi; (

    2003-01-01

    : 567-580.[37]Chen Jun, Ji Junfeng, Qiu Gang et al., Geochemical studies on intensity of chemical weathering in Luochuan loess-paleosol sequence, Science in China, Ser. D, 1998, 41(3): 235-241.[38]Gu, Z. Y., Lal, D, Liu, T. S. et al., Weathering histories of Chinese loess deposits based on uranium and thorium series nuclides and cosmogenic 10Be, Geochim. Cosmochim. Acta, 1997, 61: 5221-5231.[39]Rose, E. F., Chaussidon, M., Christian, F. L., Fractionation of boron isotopes during erosion processes: The example of Himalayan rivers, Geochim. Cosmochim. Acta, 2000, 64: 397-408.[40]Wen Qizhong, Geochemistry of Chinese Loess (in Chinese), Beijing: Science Press, 1989, 12-20.

  16. Post processing rainfall forecasts from numerical weather prediction models for short term streamflow forecasting

    Directory of Open Access Journals (Sweden)

    D. E. Robertson

    2013-05-01

    Full Text Available Sub-daily ensemble rainfall forecasts that are bias free and reliably quantify forecast uncertainty are critical for flood and short-term ensemble streamflow forecasting. Post processing of rainfall predictions from numerical weather prediction models is typically required to provide rainfall forecasts with these properties. In this paper, a new approach to generate ensemble rainfall forecasts by post processing raw NWP rainfall predictions is introduced. The approach uses a simplified version of the Bayesian joint probability modelling approach to produce forecast probability distributions for individual locations and forecast periods. Ensemble forecasts with appropriate spatial and temporal correlations are then generated by linking samples from the forecast probability distributions using the Schaake shuffle. The new approach is evaluated by applying it to post process predictions from the ACCESS-R numerical weather prediction model at rain gauge locations in the Ovens catchment in southern Australia. The joint distribution of NWP predicted and observed rainfall is shown to be well described by the assumed log-sinh transformed multivariate normal distribution. Ensemble forecasts produced using the approach are shown to be more skilful than the raw NWP predictions both for individual forecast periods and for cumulative totals throughout the forecast periods. Skill increases result from the correction of not only the mean bias, but also biases conditional on the magnitude of the NWP rainfall prediction. The post processed forecast ensembles are demonstrated to successfully discriminate between events and non-events for both small and large rainfall occurrences, and reliably quantify the forecast uncertainty. Future work will assess the efficacy of the post processing method for a wider range of climatic conditions and also investigate the benefits of using post processed rainfall forecast for flood and short term streamflow forecasting.

  17. Catalysis questions in chemical processing of coal

    Energy Technology Data Exchange (ETDEWEB)

    Paal, Z.

    1980-01-01

    A brief review is given of the literature in the field of catalytic problems related to the chemical processing of coal. As is known, these processes have become especially significant due to the energy crisis. Existing problems can be divided into two groups: one group is connected with catalytic processing of liquid products of coal destructive hydrogenation (for example, by hydrogenation of coal at high pressures, or by extraction); the other groups is connected with catalytic reactions occurring during the destructive hydrogenation or gasification of coal. Extensive basic research is required in both fields, since certain basic properties of the systems examined are still unknown. The article also gives a brief review of certain new results obtained when studying Fisher-Tropsh reactions and MeOH synthesis.

  18. Process evaluation of the Bonneville Power Administration Interim Residential Weatherization Program

    Energy Technology Data Exchange (ETDEWEB)

    Lerman, D.I.; Bronfman, B.H.

    1984-08-01

    A process evaluation of the Bonneville Power Administration (BPA) Interim Residential Weatherization Program was conducted between December of 1983 and March of 1984. For this evaluation seven of the utility participants were visited, as were the four BPA area offices serving those utilities. Interviews were also conducted with key staff members at BPA headquarters in Portland. This report describes the Interim Program and the elements of the BPA organizational structure involved in management of the program. It deals also with the implementation process at the seven utilities involved in the evaluation; perceptions of the key actors as to the strengths and weaknesses of the program; the adequacy of the BPA reimbursement for utility administrative expenses; and finally lessons for the Long-Term Program, the BPA residential program which followed the Interim Program in October 1983.

  19. Intelligent Controller Design for a Chemical Process

    Directory of Open Access Journals (Sweden)

    Mr. Glan Devadhas G

    2010-12-01

    Full Text Available Chemical process control is a challenging problem due to the strong on*line non*linearity and extreme sensitivity to disturbances of the process. Ziegler – Nichols tuned PI and PID controllers are found to provide poor performances for higher*order and non–linear systems. This paper presents an application of one*step*ahead fuzzy as well as ANFIS (adaptive*network*based fuzzy inference system tuning scheme for an Continuous Stirred Tank Reactor CSTR process. The controller is designed based on a Mamdani type and Sugeno type fuzzy system constructed to model the dynamics of the process. The fuzzy system model can take advantage of both a priori linguistic human knowledge through parameter initialization, and process measurements through on* line parameter adjustment. The ANFIS, which is a fuzzy inference system, is implemented in the framework of adaptive networks. The proposed ANFIS can construct an input*output mapping based on both human knowledge (in the form of fuzzy if*then rules and stipulated input*output data pairs. In this method, a novel approach based on tuning of fuzzy logic control as well as ANFIS for a CSTR process, capable of providing an optimal performance over the entire operating range of process are given. Here Fuzzy logic control as well as ANFIS for obtaining the optimal design of the CSTR process is explained. In this approach, the development of rule based and the formation of the membership function are evolved simultaneously. The performance of the algorithm in obtaining the optimal tuning values has been analyzed in CSTR process through computer simulation.

  20. The influence of regional urbanization and abnormal weather conditions on the processes of human climatic adaptation on mountain resorts

    Science.gov (United States)

    Artamonova, M.; Golitsyn, G.; Senik, I.; Safronov, A.; Babyakin, A.; Efimenko, N.; Povolotskaya, N.; Topuriya, D.; Chalaya, E.

    2012-04-01

    This work is a further development in the study of weather pathogenic index (WPI) and negative influence of urbanization processes on the state of people's health with adaptation disorder. This problem is socially significant. According to the data of the WHO, in the world there are from 20 to 45% of healthy people and from 40 to 80% of people with chronic diseases who suffer from the raised meteosensitivity. As a result of our researches of meteosensitivity of people during their short-duration on mountain resorts there were used negative adaptive reactions (NAR) under 26 routine tests, stress-reactions under L.H. Garkavi's hemogram, vegetative indices, tests of neuro-vascular reactivity, signs of imbalance of vegetative and neurohumoral regulation according to the data of biorhythm fractal analysis and sudden aggravations of diseases (SAD) as an indicator of negative climatic and urbanization influence. In 2010-2011 the Caucasian mountain resorts were having long periods of climatic anomalies, strengthening of anthropogenic emissions and forest fires when record-breaking high waves of NAR and SAD were noticed. There have also been specified indices ranks of weather pathogenicity from results of comparison of health characteristics with indicators of synoptico-dynamic processes according to Weather Research and Forecasting model (WRF); air ionization N+, N-, N+/N- spectra of aerosol particles (the size from 500 to 20000 nanometers) and concentrations of chemically active gases (O3, NO, NO2, ), volatile phytoorganic substances in the surface atmosphere, bactericidal characteristics of vegetation by criterion χ2 (not above 0,05). It has allowed us to develop new physiological optimum borders, norm and pessimum, to classify emergency ecologo-weather situations, to develop a new techniques of their forecasting and prevention of meteopathic reactions with meteosensitive patients (Method of treatment and the early (emergency) and planned prevention meteopatic reactions

  1. Research Project Entitled "The Dynamics and Physical Processes in The Weather and Climate System" --Part Ⅰ: A Brief Introduction

    Institute of Scientific and Technical Information of China (English)

    罗云峰; 郑文静; 周小刚

    2004-01-01

    In the beginning of the 21st century, the Tenth Five-Year Priority Research Projects of the Earth Sciences of the National Natural Science Foundation of China (NSFC) were initiated. After nearly a two-year long process to prepare, the first version of six Priority Research Projects of Earth Sciences was published in October 2001 by NSFC, viz., Local Response to Global Changes, Life Process and Environment,Dynamics and Physical Processes in the Weather and Climate System, Continental Dynamics, Regional Sustainable Development, Solar-Terrestrial Environment and Space Weather. The process involved more than 200 renowned Chinese scientists and many departments and agencies in China. The six Priority Research Projects guide the research effort of the earth sciences for the NSFC from year 2001 to 2005.This paper provides a brief introduction to the Third Priority Research Project of the Department of Earth Sciences of NSFC-Dynamics and Physical Processes in the Weather and Climate System (DPWOS).

  2. GEM-AQ/EC, an on-line global multiscale chemical weather modelling system: model development and evaluations of global aerosol climatology

    Directory of Open Access Journals (Sweden)

    S. L. Gong

    2012-04-01

    Full Text Available A global air quality modeling system GEM-AQ/EC was developed by implementing tropospheric chemistry and aerosol processes on-line into the Global Environmental Multiscale weather prediction model – GEM. Due to the multi-scale features of the GEM, the integrated model, GEM-AQ/EC, is able to investigate chemical weather at scales from global to urban domains. The current chemical mechanism is comprised of 50 gas-phase species, 116 chemical and 19 photolysis reactions, and is complemented by a sectional aerosol module CAM (The Canadian Aerosol Module with 5 aerosols types: sulphate, black carbon, organic carbon, sea-salt and soil dust. Monthly emission inventories of black carbon and organic carbon from boreal and temperate vegetation fires were assembled using the most reliable areas burned datasets by countries, from statistical databases and derived from remote sensing products of 1995–2004. The model was run for ten years from from 1995–2004 with re-analyzed meteorology on a global uniform 1 × 1° horizontal resolution domain and 28 hybrid levels extending up to 10 hPa. The simulating results were compared with various observations including surface network around the globe and satellite data. Regional features of global aerosols are reasonably captured including emission, surface concentrations and aerosol optical depth. For various types of aerosols, satisfactory correlations were achieved between modeled and observed with some degree of systematic bias possibly due to large uncertainties in the emissions used in this study. A global distribution of natural aerosol contributions to the total aerosols is obtained and compared with observations.

  3. Idaho Chemical Processing Plant Site Development Plan

    International Nuclear Information System (INIS)

    The Idaho Chemical Processing Plant (ICPP) mission is to receive and store spent nuclear fuels and radioactive wastes for disposition for Department of Energy (DOE) in a cost-effective manner that protects the safety of Idaho National Engineering Laboratory (INEL) employees, the public, and the environment by: Developing advanced technologies to process spent nuclear fuel for permanent offsite disposition and to achieve waste minimization. Receiving and storing Navy and other DOE assigned spent nuclear fuels. Managing all wastes in compliance with applicable laws and regulations. Identifying and conducting site remediation consistent with facility transition activities. Seeking out and implementing private sector technology transfer and cooperative development agreements. Prior to April 1992, the ICPP mission included fuel reprocessing. With the recent phaseout of fuel reprocessing, some parts of the ICPP mission have changed. Others have remained the same or increased in scope

  4. Idaho Chemical Processing Plant failure rate database

    International Nuclear Information System (INIS)

    This report represents the first major upgrade to the Idaho Chemical Processing Plant (ICPP) Failure Rate Database. This upgrade incorporates additional site-specific and generic data while improving on the previous data reduction techniques. In addition, due to a change in mission at the ICPP, the status of certain equipment items has changed from operating to standby or off-line. A discussion of how this mission change influenced the relevance of failure data also has been included. This report contains two data sources: the ICPP Failure Rate Database and a generic failure rate database. A discussion is presented on the approaches and assumptions used to develop the data in the ICPP Failure Rate Database. The generic database is included along with a short discussion of its application. A brief discussion of future projects recommended to strengthen and lend credibility to the ICPP Failure Rate Database also is included

  5. Thermodynamics principles characterizing physical and chemical processes

    CERN Document Server

    Honig, Jurgen M

    1999-01-01

    This book provides a concise overview of thermodynamics, and is written in a manner which makes the difficult subject matter understandable. Thermodynamics is systematic in its presentation and covers many subjects that are generally not dealt with in competing books such as: Carathéodory''s approach to the Second Law, the general theory of phase transitions, the origin of phase diagrams, the treatment of matter subjected to a variety of external fields, and the subject of irreversible thermodynamics.The book provides a first-principles, postulational, self-contained description of physical and chemical processes. Designed both as a textbook and as a monograph, the book stresses the fundamental principles, the logical development of the subject matter, and the applications in a variety of disciplines. This revised edition is based on teaching experience in the classroom, and incorporates many exercises in varying degrees of sophistication. The stress laid on a didactic, logical presentation, and on the relat...

  6. Water geochemistry of the Qiantangjiang River, East China: Chemical weathering and CO2 consumption in a basin affected by severe acid deposition

    Science.gov (United States)

    Liu, Wenjing; Shi, Chao; Xu, Zhifang; Zhao, Tong; Jiang, Hao; Liang, Chongshan; Zhang, Xuan; Zhou, Li; Yu, Chong

    2016-09-01

    The chemical composition of the Qiantangjiang River, the largest river in Zhejiang province in eastern China, was measured to understand the chemical weathering of rocks and the associated CO2 consumption and anthropogenic influences within a silicate-dominated river basin. The average total dissolved solids (TDS, 113 mg l-1) and total cation concentration (TZ+, 1357 μeq l-1) of the river waters are comparable with those of global major rivers. Ca2+ and HCO3- followed by Na2+ and SO42-, dominate the ionic composition of the river water. There are four major reservoirs (carbonates, silicates, atmospheric and anthropogenic inputs) contributing to the total dissolved load of the investigated rivers. The dissolved loads of the rivers are dominated by both carbonate and silicate weathering, which together account for about 76.3% of the total cationic load origin. The cationic chemical weathering rates of silicate and carbonate for the Qiantangjiang basin are estimated to be approximately 4.9 ton km-2 a-1 and 13.9 ton km-2 a-1, respectively. The calculated CO2 consumption rates with the assumption that all the protons involved in the weathering reaction are provided by carbonic acid are 369 × 103 mol km-2 a-1 and 273 × 103 mol km-2 a-1 by carbonate and silicate weathering, respectively. As one of the most severe impacted area by acid rain in China, H2SO4 from acid precipitation is also an important proton donor in weathering reactions. When H2SO4 is considered, the CO2 consumption rates for the river basin are estimated at 286 × 103 mol km-2 a-1 for carbonate weathering and 211 × 103 mol km-2 a-1 for silicate weathering, respectively. The results highlight that the drawdown effect of CO2 consumption by carbonate and silicate weathering can be largely overestimated if the role of sulfuric acid is ignored, especially in the area heavily impacted by acid deposition like Qiantangjiang basin. The actual CO2 consumption rates (after sulfuric acid weathering effect

  7. A chemical index of weathering without effect of wind sorting: Fe/Mg ratios in the acid-insoluble phases of loess deposits

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Chemical analysis of acid-insoluble fractions in loess and paleosols shows that concentrations of Fe and Mg were under control of wind sorting and post-depositional weathering-pedogenesis. The former caused Fe and Mg concentrated in the finer grain-size fractions, displaying synchronous variations, while the latter made Fe and Mg separated, leading to Fe retained in the weathered section and Mg leached out. Therefore, Fe/Mg ratios in the acid insoluble fraction of loess and paleosols can eliminate the effect of wind sorting and serve as an excellent proxy record on intensity of weathering-pedogenesis. Based on calculation,leaching percentage of Mg in the paleosol S1 from the Luochuan, Xifeng and Huanxian sections is 15%, 11% and 2%,respectively, and on average 9% for the paleosols S2-S14from the Luochuan section, with the highest value amounting to 22% in Ss-1, suggesting the strongest weathering-pedogenesis.``

  8. 21 CFR 570.19 - Pesticide chemicals in processed foods.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Pesticide chemicals in processed foods. 570.19... (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS FOOD ADDITIVES General Provisions § 570.19 Pesticide chemicals in processed foods. When pesticide chemical residues occur in processed foods due to the use...

  9. 21 CFR 170.19 - Pesticide chemicals in processed foods.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Pesticide chemicals in processed foods. 170.19... (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES General Provisions § 170.19 Pesticide chemicals in processed foods. When pesticide chemical residues occur in processed foods due to the use...

  10. Ameliorating physical and chemical properties of highly weathered soils in the tropics with charcoal: A review

    OpenAIRE

    Glaser, B.; Lehmann, J.; Zech, W.

    2002-01-01

    Metadata only record Rapid turnover of organic matter leads to a low efficiency of organic fertilizers applied to increase and sequester C in soils of the humid tropics. Charcoal was reported to be responsible for high soil organic matter contents and soil fertility of anthropogenic soils (Terra Preta) found in central Amazonia. Therefore, we reviewed the available information about the physical and chemical properties of charcoal as affected by different combustion procedures, and the eff...

  11. Post-Wisconsinan Chemical Weathering Rates and Trajectories From a 13,400-Year Sediment Core Record of Lead Isotopic Ratios in Maine

    Science.gov (United States)

    Perry, R. H.; Norton, S. A.; Koons, P. O.; Handley, M.

    2008-12-01

    Lead isotopic ratios recorded in a 5.3-m 13.4-ka 14C-dated lake sediment core from Sargent Mountain Pond, Maine (USA) are interpreted as an archive of post-glacial chemical weathering. Early weathering yielded highly radiogenic sediment from the preferential release of U and Th decay products (206Pb, 207Pb, and 208Pb) from accessory mineral phases in the catchment's predominantly-granitic till and bedrock relative to non-radiogenic 204Pb from the more abundant primary minerals. Values for 207Pb/206Pb in the sediment increased rapidly from 0.799 to 0.814 in the catchment's first 4,000 years of post-Wisconsinan weathering, and thereafter increased only slightly to just prior to the 19th century. Values for 208Pb/204Pb, 207Pb/204Pb, and 206Pb/204Pb decline over the same time-scale, as a result of decreasing radiogenic Pb being released from catchment weathering. Our results are consistent with: (1) the published interpretation of Pb isotopic variation in ferromanganese ocean crusts as a reflection of continental-scale glacial-interglacial chemical weathering cycles, (2) bench-scale whole-rock weathering experiments, and (3) soil chronosequence Pb isotope dissolution experiments and bridge the gap between short-term, mineral-scale experiments and long-term, ocean sediment records. We establish a time-scale for depletion of accessory minerals, and loss of their Pb isotopic signature at one catchment, and document the concurrent shift to slower primary mineral-controlled chemical weathering after deglaciation.

  12. Studying chemical vapor deposition processes with theoretical chemistry

    OpenAIRE

    Pedersen, Henrik; Elliott, Simon D.

    2014-01-01

    In a chemical vapor deposition (CVD) process, a thin film of some material is deposited onto a surface via the chemical reactions of gaseous molecules that contain the atoms needed for the film material. These chemical reactions take place on the surface and in many cases also in the gas phase. To fully understand the chemistry in the process and thereby also have the best starting point for optimizing the process, theoretical chemical modeling is an invaluable tool for providing atomic-scale...

  13. Weathering processes and the composition of inorganic material transported through the orinoco river system, Venezuela and Colombia

    Science.gov (United States)

    Stallard, R.F.; Koehnken, L.; Johnsson, M.J.

    1991-01-01

    The composition of river-borne material in the Orinoco River system is related primarily to erosion regime, which in turn is related to tectonic setting; especially notable is the contrast between material derived from tectonically active mountain belts and that from stable cratonic regions. For a particular morpho-tectonic region, the compositional suites of suspended sediment, bed material, overback deposits, and dissolved phases are fairly uniform are are typically distinct from whose of other regions. For each region, a consistent set of chemical weathering reactions can be formulated to explain the composition of dissolved and solid loads. In developing these formulations, erosion on slopes and storage of solids in soils and alluvial sediments are important considerations. Compositionally verymature sediment is derived from areas of thick soils where erosion is transport limited and from areas where sediments are stored for extended periods of time in alluvial deposits. Compositionally immature sediments are derived from tectonically active mountain belts where erosion is weathering limited. Weathering-limited erosion also is important in the elevated parts of the Guayana Shield within areas of sleep topography. Compared to the mountain belts, sediments derived from elevated parts of the Shield are more mature. A greater degree of chemical weathering seems to be needed to erode the rock types typical of the Shield. The major-element chemistry and mineral composition of sediment delivered by the Orinoco River to the ocean are controlled by rivers that have their headwaters in mountain belts and cross the Llanos, a region of alluvial plains within the foreland basin. The composition of sediments in rivers that drain the Shield seems to be established primarily at the site of soil formation, whereas for rivers that drain the mountain belts, additional weathering occurs during s episodes of storage on alluvial plains as sediments are transported across the Llanos

  14. Review and Perspectives of the Study on Chemical Weathering and Hydrochemistry in River Basin%流域化学风化与河流水化学研究综述与展望

    Institute of Scientific and Technical Information of China (English)

    解晨骥; 高全洲; 陶贞

    2012-01-01

    Since the industrial revolution atmospheric CO2 concentration has been rising, the topic about temporal and spatial variation of carbon sink and source has been a hotspot. Chemical weathering of mineral rocks especially silicates is an important carbon sink in global biological geochemistry cycle. Factors controlling chemical weathering rate are various but their importance and function mechanism deserve further studying. Human activities have made more and more sulfuric acid to take part in the chemical weathering process, it will accelerate the rate of chemical weathering while its function mechanism is complicated. At present the methods used to discriminate water chemistry and ion origin of rivers can be classified into qualitative and quantitative methods, the former contains Gibbs diagram, ternary diagram and end member diagram while the latter includes mass balance method and isotope tracer method. Nowadays researches about the factors controlling chemical weathering rate pay more attention to the correlation between single factor and chemical weathering rate, the introduction of the mathematical statistical methods will make the researches more rigorous and credible. In the processes of the chemical weathering sulfuric acid is seldom researched, with the increasingly serious acid rain phenomenon, the issues deserve important research value. The carbon sink effect due to carbonate chemical weathering on short timescale is unnegligible, which should be studied further.%工业革命以来大气CO2浓度不断上升,其源汇机制和时空变化成为学界关注的焦点.岩石特别是硅酸盐类岩石的化学风化是全球生物地球化学循环的重要碳汇.控制化学风化速率的因素较为复杂,各因素作用的机理和重要性还不完全明确.源于人类排放的H2SO4普遍参与到化学风化过程中,这加快了流域化学风化的速率,但这一过程对碳汇效应的影响机理尚缺乏足够的研

  15. ADVANCED OXIDATION PROCESSES (AOP'S FOR THE TREATMENT OF CCL CHEMICALS

    Science.gov (United States)

    Research on treatment of Contaminant Candidate List (CCL) chemicals is being conducted. Specific groups of contaminants on the CCL will be evaluated using numerous advanced oxidation processes (AOPs). Initially, these CCL contaminants will be evaluated in groups based on chemical...

  16. New Space Weather and Nonlinear Waves and Processes Prize announced for 2013

    Science.gov (United States)

    Thompson, Victoria

    2012-01-01

    At the 2011 Fall Meeting in San Francisco, Calif., AGU announced the creation of a new award: the Space Weather and Nonlinear Waves and Processes Prize. The prize, which is being made possible by a generous contribution from longtime AGU members and NASA Jet Propulsion Laboratory (JPL), California Institute of Technology, scientists Bruce Tsurutani and Olga Verkhoglyadova, will recognize an AGU member scientist and will come with a $10,000 award. Tsurutani has served as a researcher with JPL since 1972 and is currently a senior research scientist. He was also the president of AGU's Space Physics and Aeronomy section from 1990 to 1992 and is a recipient of AGU's John Adam Fleming Medal, given “for original research and technical leadership in geomagnetism, atmospheric electricity, aeronomy, space physics, and related sciences.” Verkhoglyadova served as a professor of space physics in the Department of Astrophysics and Space Physics at Taras Shevchenko National University of Kyiv, in the Ukraine, prior to coming to the United States. Their leadership and dedication to AGU and to their field are apparent in their passion for this prize.

  17. Exploring Model Error through Post-processing and an Ensemble Kalman Filter on Fire Weather Days

    Science.gov (United States)

    Erickson, Michael J.

    The proliferation of coupling atmospheric ensemble data to models in other related fields requires a priori knowledge of atmospheric ensemble biases specific to the desired application. In that spirit, this dissertation focuses on elucidating atmospheric ensemble model bias and error through a variety of different methods specific to fire weather days (FWDs) over the Northeast United States (NEUS). Other than a handful of studies that use models to predict fire indices for single fire seasons (Molders 2008, Simpson et al. 2014), an extensive exploration of model performance specific to FWDs has not been attempted. Two unique definitions for FWDs are proposed; one that uses pre-existing fire indices (FWD1) and another from a new statistical fire weather index (FWD2) relating fire occurrence and near-surface meteorological observations. Ensemble model verification reveals FWDs to have warmer (> 1 K), moister (~ 0.4 g kg-1) and less windy (~ 1 m s-1) biases than the climatological average for both FWD1 and FWD2. These biases are not restricted to the near surface but exist through the entirety of the planetary boundary layer (PBL). Furthermore, post-processing methods are more effective when previous FWDs are incorporated into the statistical training, suggesting that model bias could be related to the synoptic flow pattern. An Ensemble Kalman Filter (EnKF) is used to explore the effectiveness of data assimilation during a period of extensive FWDs in April 2012. Model biases develop rapidly on FWDs, consistent with the FWD1 and FWD2 verification. However, the EnKF is effective at removing most biases for temperature, wind speed and specific humidity. Potential sources of error in the parameterized physics of the PBL are explored by rerunning the EnKF with simultaneous state and parameter estimation (SSPE) for two relevant parameters within the ACM2 PBL scheme. SSPE helps to reduce the cool temperature bias near the surface on FWDs, with the variability in parameter

  18. Geochemistry of fine-grained sediments in the Yangtze River and the implications for provenance and chemical weathering in East Asia

    Science.gov (United States)

    He, Mengying; Zheng, Hongbo; Clift, Peter D.; Tada, Ryuji; Wu, Weihua; Luo, Chao

    2015-12-01

    In order to interpret the marine clastic record preserved in the sedimentary basins of the East Asian marginal seas, it is important to understand how sediment transport and chemical weathering affect the composition of sediment enroute to its sink. Here we present a new data set for fine-grained sediment (China Sea. We demonstrate that there is no significant coherent downstream variation in the major element contents, which are generally more enriched than the average upper continental crust, except for water-soluble elements including Sr, Rb, Na, and K. Nd isotopes show that most of the sediment comes from the eastern and middle Yangtze Craton, as well as the Songpan-Garze Terrane. Chemical weathering varies significantly across the basin with upstream tributary sediments being relatively unweathered compared to those in the lower reaches. However, sediments in the main Yangtze stream show no trend in chemical weathering along its course, with some of the least weathered materials being found closest to the delta. Grain size and the abundance of hydrodynamically sorted heavy minerals affect the bulk geochemistry, especially the rare earth elements (REEs).

  19. Experimental studies on the weathering of chemicals in a field trial to predict their behaviour in case of a spill

    International Nuclear Information System (INIS)

    Most of the world's production of vegetable oil is transported by sea. In 2001, nearly 850,000 tons of vegetable oil entered and left harbours in France. This trend increases the risk of accidental spills at sea. The physical state of vegetable oil changes when it is spilled at sea, turning this non-toxic product into a pollutant that damages the marine ecosystem. This study demonstrated how vegetable oil could react when spilled at sea. A series of field studies were conducted to obtain experimental data on the behaviour of vegetable oil both on the surface of water and in the water column. Castor oil, soybean oil, oleic acid and dioctylphtalate were released at sea and the dispersion of the oil in the water was monitored with a fluorimeter. Measurements were taken to a depth of 1 metre. Emulsification and viscosity kinetics were monitored. The study showed that the behaviour of the 4 products depends on the nature of the product and weather conditions such as wind and sea surface state. Vegetable oil spilled at sea behaves differently from spilled chemical products in terms of solubility. It was suggested that in the case of an accidental spill at sea, emergency responders should first pump the oil and then use dispersants. 6 refs., 2 tabs., 11 figs

  20. Chemical weathering rates of a soil chronosequence on granitic alluvium: I. Quantification of mineralogical and surface area changes and calculation of primary silicate reaction rates

    Science.gov (United States)

    White, A.F.; Blum, A.E.; Schulz, M.S.; Bullen, T.D.; Harden, J.W.; Peterson, M.L.

    1996-01-01

    Mineral weathering rates are determined for a series of soils ranging in age from 0.2-3000 Ky developed on alluvial terraces near Merced in the Central Valley of California. Mineralogical and elemental abundances exhibit time-dependent trends documenting the chemical evolution of granitic sand to residual kaolinite and quartz. Mineral losses with time occur in the order: hornblende > plagioclase > K-feldspar. Maximum volume decreases of >50% occur in the older soils. BET surface areas of the bulk soils increase with age, as do specific surface areas of aluminosilicate mineral fractions such as plagioclase, which increases from 0.4-1.5 m2 g-1 over 600 Ky. Quartz surface areas are lower and change less with time (0.11-0.23 m2 g-1). BET surface areas correspond to increasing external surface roughness (?? = 10-600) and relatively constant internal surface area (??? 1.3 m2 g-1). SEM observations confirm both surface pitting and development of internal porosity. A numerical model describes aluminosilicate dissolution rates as a function of changes in residual mineral abundance, grain size distributions, and mineral surface areas with time. A simple geometric treatment, assuming spherical grains and no surface roughness, predicts average dissolution rates (plagioclase, 10-17.4; K-feldspar, 10-17.8; and hornblende, 10-17.5 mol cm-1 s-1) that are constant with time and comparable to previous estimates of soil weathering. Average rates, based on BET surface area measurements and variable surface roughnesses, are much slower (plagioclase, 10-19.9; K-feldspar, 10-20.5; and hornblende 10-20.1 mol cm-2 s-1). Rates for individual soil horizons decrease by a factor of 101.5 over 3000 Ky indicating that the surface reactivities of minerals decrease as the physical surface areas increase. Rate constants based on BET estimates for the Merced soils are factors of 103-104 slower than reported experimental dissolution rates determined from freshly prepared silicates with low surface

  1. Comparison between conventional chemical processes and bioprocesses in cotton fabrics

    OpenAIRE

    Mojsov, Kiro

    2015-01-01

    Textile processing is a growing industry that traditionally has used a lot of water, energy and harsh chemicals. They are also not easily biodegradable. Biotechnology in textiles is one of the revolutionary ways to promote the textile field. Bio-processing were accompanied by a significant lower demand of energy, water, chemicals, time and costs. Due to the ever growing costs for water and energy worldwide investigations are carried out to substitute conventional chemical textile processes by...

  2. Total chemical management in photographic processing

    Science.gov (United States)

    Luden, Charles; Schultz, Ronald

    1985-01-01

    The mission of the U. S. Geological Survey's Earth Resources Observation Systems (EROS) Data Center is to produce high-quality photographs of the earth taken from aircraft and Landsat satellite. In order to meet the criteria of producing research-quality photographs, while at the same time meeting strict environmental restrictions, a total photographic chemical management system was installed. This involved a three-part operation consisting of the design of a modern chemical analysis laboratory, the implementation of a chemical regeneration system, and the installation of a waste treatment system, including in-plant pretreatment and outside secondary waste treatment. Over the last ten years the result of this program has yielded high-quality photographs while saving approximately 30,000 per year and meeting all Environmental Protection Agency (EPA) restrictions.

  3. Applications of Process Synthesis: Moving from Conventional Chemical Processes towards Biorefinery Processes

    DEFF Research Database (Denmark)

    Yuan, Zhihong; Chen, Bingzhen; Gani, Rafiqul

    2013-01-01

    , biorefinery processes for converting biomass-derived carbohydrates into transportation fuels and chemicals are now gaining more and more attention from both academia and industry. Process synthesis, which has played a vital role for the development, design and operation of (petro) chemical processes, can be......Concerns about diminishing petroleum reserves, enhanced worldwide demand for fuels and fluctuations in the global oil market, together with climate change and national security have promoted many initiatives for exploring alternative, non-petroleum based processes. Among these initiatives...

  4. Ionic Liquids: Green Solvents for Chemical Processing

    OpenAIRE

    Antonia Pérez de los Ríos; Angel Irabien; Frank Hollmann; Francisco José Hernández Fernández

    2013-01-01

    Ionic liquids are organic salts, usually consisting of an organic cation and a polyatomic inorganic anion, which are liquid under 100∘ C. The most relevant properties of ionic liquids are their almost negligible vapour pressure. Furthermore, their physical and chemical properties can be fine-tuned by the adequate selection of the cation and anion constituents. Ionic liquids have been recognized as environmental benign alternative to volatile organic solvents. Applicati...

  5. Weather variability, ecological processes and optimization of soil micro-environment for rangeland restoration

    Science.gov (United States)

    Arid and semi-arid rangelands occupy over half of the earth’s surface and are characterized by relatively high variability in seasonal and annual patterns of precipitation. Invasive plants compete for soil and water resources and exacerbate inherent weather limitations for native plant establishmen...

  6. Stereodynamics: From elementary processes to macroscopic chemical reactions

    Energy Technology Data Exchange (ETDEWEB)

    Kasai, Toshio [Department of Chemistry, National Taiwan University, Taipei 106, Taiwan (China); Graduate School of Science, Department of Chemistry, Osaka University, Toyonaka, 560-0043 Osaka (Japan); Che, Dock-Chil [Graduate School of Science, Department of Chemistry, Osaka University, Toyonaka, 560-0043 Osaka (Japan); Tsai, Po-Yu [Department of Chemistry, National Taiwan University, Taipei 106, Taiwan (China); Department of Chemistry, National Chung Hsing University, Taichung 402, Taiwan (China); Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan (China); Lin, King-Chuen [Department of Chemistry, National Taiwan University, Taipei 106, Taiwan (China); Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 106, Taiwan (China); Palazzetti, Federico [Scuola Normale Superiore, Pisa (Italy); Dipartimento di Chimica Biologia e Biotecnologie, Università di Perugia, 06123 Perugia (Italy); Aquilanti, Vincenzo [Dipartimento di Chimica Biologia e Biotecnologie, Università di Perugia, 06123 Perugia (Italy); Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche, Roma (Italy); Instituto de Fisica, Universidade Federal da Bahia, Salvador (Brazil)

    2015-12-31

    This paper aims at discussing new facets on stereodynamical behaviors in chemical reactions, i.e. the effects of molecular orientation and alignment on reactive processes. Further topics on macroscopic processes involving deviations from Arrhenius behavior in the temperature dependence of chemical reactions and chirality effects in collisions are also discussed.

  7. Stereodynamics: From elementary processes to macroscopic chemical reactions

    International Nuclear Information System (INIS)

    This paper aims at discussing new facets on stereodynamical behaviors in chemical reactions, i.e. the effects of molecular orientation and alignment on reactive processes. Further topics on macroscopic processes involving deviations from Arrhenius behavior in the temperature dependence of chemical reactions and chirality effects in collisions are also discussed

  8. Chemical process safety management within the Department of Energy

    International Nuclear Information System (INIS)

    Although the Department of Energy (DOE) is not well known for its chemical processing activities, the DOE does have a variety of chemical processes covered under OSHA's Rule for Process Safety Management of Highly Hazardous Chemicals (the PSM Standard). DOE, like industry, is obligated to comply with the PSM Standard. The shift in the mission of DOE away from defense programs toward environmental restoration and waste management has affected these newly forming process safety management programs within DOE. This paper describes the progress made in implementing effective process safety management programs required by the PSM Standard and discusses some of the trends that have supported efforts to reduce chemical process risks within the DOE. In June of 1994, a survey of chemicals exceeding OSHA PSM or EPA Risk Management Program threshold quantities (TQs) at DOE sites found that there were 22 processes that utilized toxic or reactive chemicals over TQs; there were 13 processes involving flammable gases and liquids over TQs; and explosives manufacturing occurred at 4 sites. Examination of the survey results showed that 12 of the 22 processes involving toxic chemicals involved the use of chlorine for water treatment systems. The processes involving flammable gases and liquids were located at the Strategic Petroleum Reserve and Naval petroleum Reserve sites

  9. News: Good chemical manufacturing process criteria

    Science.gov (United States)

    This news column covers topics relating to manufacturing criteria, machine to machine technology, novel process windows, green chemistry indices, business resilience, immobilized enzymes, and Bt crops.

  10. Fluid flow for chemical and process engineers

    CERN Document Server

    Holland, F

    1995-01-01

    This major new edition of a popular undergraduate text covers topics of interest to chemical engineers taking courses on fluid flow. These topics include non-Newtonian flow, gas-liquid two-phase flow, pumping and mixing. It expands on the explanations of principles given in the first edition and is more self-contained. Two strong features of the first edition were the extensive derivation of equations and worked examples to illustrate calculation procedures. These have been retained. A new extended introductory chapter has been provided to give the student a thorough basis to understand the methods covered in subsequent chapters.

  11. Time-scales of erosion and weathering processes in the Himalayan river system: Element and isotope approach using the U-series

    International Nuclear Information System (INIS)

    The time-scales of erosion and weathering processes are key parameters which need to be determined to understand the response of the reliefs to external forcing like tectonics, climate and human activities. They were recovered by using U-series nuclides analyzed in sediments and suspended materials carried by the Himalayan rivers of the Ganges and Brahmaputra basins. In the Ganges basin, the time-scales of weathering determined from the study of coarse sediments carried by the Kali Gandaki range from several ky, where the uplift is located, to 350 ky. Such values indicate that the bed-rocks are in situ weathered for a long period before the weathering residual products get transported in the rivers as coarse sediments. At the outlet of the high range, these sediments are carried by the tributaries of the Ganges, the Gandak and Ghaghara, during a transfer period of about 100 ka. The study of the sediments at the outlet of the Brahmaputra tributaries allows to propose time-scales of weathering ranging from 110 to 270 ky. Such long periods confirm that during their transfer in the plains, the sediments are temporarily trapped at several places in the basins. In the Ganges and Brahmaputra rivers, the time-scales of sedimentary transfer are 575 and 160 ky, respectively. These values, which are of the same order as their response times, are much longer than the timescales of the Quaternary climate oscillations. It confirms the buffering action of the asiatic alluvial plains for the high-frequency sediment flux variations in response to external forcing in the chain. The study of suspended materials suggests that their chemical compositions result from the mixing of coarse river sediments with fine particles from various locations in the basin which are affected by vegetation recycling. By contrast to coarse sediments, the time-scales of transfer for the suspended materials are fast, e.g. a few ky, pointing the potential of U-series nuclides to assess particle transport

  12. BEHAVIOR OF MERCURY DURING DWPF CHEMICAL PROCESS CELL PROCESSING

    Energy Technology Data Exchange (ETDEWEB)

    Zamecnik, J.; Koopman, D.

    2012-04-09

    The Defense Waste Processing Facility has experienced significant issues with the stripping and recovery of mercury in the Chemical Processing Cell (CPC). The stripping rate has been inconsistent, often resulting in extended processing times to remove mercury to the required endpoint concentration. The recovery of mercury in the Mercury Water Wash Tank has never been high, and has decreased significantly since the Mercury Water Wash Tank was replaced after the seventh batch of Sludge Batch 5. Since this time, essentially no recovery of mercury has been seen. Pertinent literature was reviewed, previous lab-scale data on mercury stripping and recovery was examined, and new lab-scale CPC Sludge Receipt and Adjustment Tank (SRAT) runs were conducted. For previous lab-scale data, many of the runs with sufficient mercury recovery data were examined to determine what factors affect the stripping and recovery of mercury and to improve closure of the mercury material balance. Ten new lab-scale SRAT runs (HG runs) were performed to examine the effects of acid stoichiometry, sludge solids concentration, antifoam concentration, form of mercury added to simulant, presence of a SRAT heel, operation of the SRAT condenser at higher than prototypic temperature, varying noble metals from none to very high concentrations, and higher agitation rate. Data from simulant runs from SB6, SB7a, glycolic/formic, and the HG tests showed that a significant amount of Hg metal was found on the vessel bottom at the end of tests. Material balance closure improved from 12-71% to 48-93% when this segregated Hg was considered. The amount of Hg segregated as elemental Hg on the vessel bottom was 4-77% of the amount added. The highest recovery of mercury in the offgas system generally correlated with the highest retention of Hg in the slurry. Low retention in the slurry (high segregation on the vessel bottom) resulted in low recovery in the offgas system. High agitation rates appear to result in lower

  13. Weathering processes at the natural nuclear reactor of Bangombe (Gabon). Identification and geochemical modeling of the retention and migration mechanisms of uranium and rare earth elements

    International Nuclear Information System (INIS)

    The natural nuclear fission reactor of Bangombe (Gabon) was discovered in 1985. It is located 30 km SE of the uranium Oklo ore deposit which is well-known for its reactors discovered in 1972. In contrast to the latter ones, the reaction zone of Bangombe is situated close to the surface and therefore has been affected by supergene weathering processes. The purpose of this study was to characterize the main effects related to these alteration processes on the rocks surrounding the Bangombe reactor zone as well as to determine the major mechanisms, influencing the migration and retention of U and REE in this geological system. The different approaches considered in this study comprise mineralogical and geochemical investigations, mass balance calculations, sequential extraction experiments as well as thermodynamic simulations. It could be shown that the present rock and mineral assemblages result from a complex and multi-stage history during which the rocks were affected by diagenetic, hydrothermal, tectonic and recent alteration processes. Multiple transformations led to the setting of different horizons characterized by very specific physico-chemical conditions and mineral associations. It has been shown that in the various units of the weathering sequence, the mechanisms and mineral phases determining the U and REE migration/retention behaviour are quite different and highly dependent on the physico-chemical conditions prevailing in the ambient environment. Apart from residual and neo-formed clays, especially amorphous and crystalline Fe- and Mn oxides and oxy-hydroxides, phosphates as well as minor phases such as carbonates and heavy minerals were identified to play an important role in REE and U mobility. The acquisition of hydrodynamic data enabled to simulate water-rock interaction and mass-transfer processes which have been produced during the alteration of the Bangombe reactor zone. Thermodynamic simulations showed that elevated U-concentrations downstream

  14. Chemical weathering rates of a soil chronosequence on granitic alluvium: III. Hydrochemical evolution and contemporary solute fluxes and rates

    Science.gov (United States)

    White, A.F.; Schulz, M.S.; Vivit, D.V.; Blum, A.E.; Stonestrom, D.A.; Harden, J.W.

    2005-01-01

    Although long-term changes in solid-state compositions of soil chronosequences have been extensively investigated, this study presents the first detailed description of the concurrent hydrochemical evolution and contemporary weathering rates in such sequences. The most direct linkage between weathering and hydrology over 3 million years of soil development in the Merced chronosequence in Central California relates decreasing permeability and increasing hydrologic heterogeneity to the development of secondary argillic horizons and silica duripans. In a highly permeable, younger soil (40 kyr old), pore water solutes reflect seasonal to decadal-scale variations in rainfall and evapotranspiration (ET). This climate signal is strongly damped in less permeable older soils (250 to 600 kyr old) where solutes increasingly reflect weathering inputs modified by heterogeneous flow. Elemental balances in the soils are described in terms of solid state, exchange and pore water reservoirs and input/output fluxes from precipitation, ET, biomass, solute discharge and weathering. Solute mineral nutrients are strongly dependent on biomass variations as evidenced by an apparent negative K weathering flux reflecting aggradation by grassland plants. The ratios of solute Na to other base cations progressively increase with soil age. Discharge fluxes of Na and Si, when integrated over geologic time, are comparable to solid-state mass losses in the soils, implying similar past weathering conditions. Similarities in solute and sorbed Ca/Mg ratios reflect short-term equilibrium with the exchange reservoir. Long-term consistency in solute ratios, when contrasted against progressive decreases in solid-state Ca/Mg, requires an additional Ca source, probably from dry deposition. Amorphous silica precipitates from thermodynamically-saturated pore waters during periods of high evapotranspiration and result in the formation of duripans in the oldest soils. The degree of feldspar and secondary

  15. Efficient Nonlinear Programming Algorithms for Chemical Process Control and Operations

    Science.gov (United States)

    Biegler, Lorenz T.

    Optimization is applied in numerous areas of chemical engineering including the development of process models from experimental data, design of process flowsheets and equipment, planning and scheduling of chemical process operations, and the analysis of chemical processes under uncertainty and adverse conditions. These off-line tasks require the solution of nonlinear programs (NLPs) with detailed, large-scale process models. Recently, these tasks have been complemented by time-critical, on-line optimization problems with differential-algebraic equation (DAE) process models that describe process behavior over a wide range of operating conditions, and must be solved sufficiently quickly. This paper describes recent advances in this area especially with dynamic models. We outline large-scale NLP formulations and algorithms as well as NLP sensitivity for on-line applications, and illustrate these advances on a commercial-scale low density polyethylene (LDPE) process.

  16. The role of reaction affinity and secondary minerals in regulating chemical weathering rates at the Santa Cruz Soil Chronosequence, California

    Energy Technology Data Exchange (ETDEWEB)

    Maher, K.; Steefel, C. I.; White, A.F.; Stonestrom, D.A.

    2009-02-25

    In order to explore the reasons for the apparent discrepancy between laboratory and field weathering rates and to determine the extent to which weathering rates are controlled by the approach to thermodynamic equilibrium, secondary mineral precipitation and flow rates, a multicomponent reactive transport model (CrunchFlow) was used to interpret soil profile development and mineral precipitation and dissolution rates at the 226 ka marine terrace chronosequence near Santa Cruz, CA. Aqueous compositions, fluid chemistry, transport, and mineral abundances are well characterized (White et al., 2008, GCA) and were used to constrain the reaction rates for the weathering and precipitating minerals in the reactive transport modeling. When primary mineral weathering rates are calculated with either of two experimentally determined rate constants, the nonlinear, parallel rate law formulation of Hellmann and Tisser and [2006] or the aluminum inhibition model proposed by Oelkers et al. [1994], modeling results are consistent with field-scale observations when independently constrained clay precipitation rates are accounted for. Experimental and field rates, therefore, can be reconciled at the Santa Cruz site. Observed maximum clay abundances in the argillic horizons occur at the depth and time where the reaction fronts of the primary minerals overlap. The modeling indicates that the argillic horizon at Santa Cruz can be explained almost entirely by weathering of primary minerals and in situ clay precipitation accompanied by undersaturation of kaolinite at the top of the profile. The rate constant for kaolinite precipitation was also determined based on model simulations of mineral abundances and dissolved Al, SiO{sub 2}(aq) and pH in pore waters. Changes in the rate of kaolinite precipitation or the flow rate do not affect the gradient of the primary mineral weathering profiles, but instead control the rate of propagation of the primary mineral weathering fronts and thus total

  17. Property Modelling for Applications in Chemical Product and Process Design

    DEFF Research Database (Denmark)

    Gani, Rafiqul

    group parameter is missing, the atom connectivity based model is employed to predict the missing group interaction. In this way, a wide application range of the property modeling tool is ensured. Based on the property models, targeted computer-aided techniques have been developed for design and analysis...... of organic chemicals, polymers, mixtures as well as separation processes. The presentation will highlight the framework (ICAS software) for property modeling, the property models and issues such as prediction accuracy, flexibility, maintenance and updating of the database. Also, application issues......Physical-chemical properties of pure chemicals and their mixtures play an important role in the design of chemicals based products and the processes that manufacture them. Although, the use of experimental data in design and analysis of chemicals based products and their processes is desirable...

  18. Weathering: methods and techniques to measure

    Science.gov (United States)

    Lopez-Arce, P.; Zornoza-Indart, A.; Alvarez de Buergo, M.; Fort, R.

    2012-04-01

    Surface recession takes place when weathered material is removed from the rocks. In order to know how fast does weathering and erosion occur, a review of several methods, analyses and destructive and non-destructive techniques to measure weathering of rocks caused by physico-chemical changes that occur in bedrocks due to salt crystallization, freezing-thaw, thermal shock, influence of water, wind, temperature or any type of environmental agent leading to weathering processes and development of soils, in-situ in the field or through experimental works in the laboratory are addressed. From micro-scale to macro-scale, from the surface down to more in depth, several case studies on in-situ monitoring of quantification of decay on soils and rocks from natural landscapes (mountains, cliffs, caves, etc) or from urban environment (foundations or facades of buildings, retaining walls, etc) or laboratory experimental works, such as artificial accelerated ageing tests (a.a.e.e.) or durability tests -in which one or more than one weathering agents are selected to assess the material behaviour in time and in a cyclic way- performed on specimens of these materials are summarised. Discoloration, structural alteration, precipitation of weathering products (mass transfer), and surface recession (mass loss) are all products of weathering processes. Destructive (SEM-EDX, optical microscopy, mercury intrusion porosimetry, drilling resistance measurement, flexural and compression strength) and Non-destructive (spectrophotocolorimetry, 3D optical surface roughness, Schmidt hammer rebound tester, ultrasound velocity propagation, Nuclear Magnetic Resonance NMR, X ray computed micro-tomography or CT-scan, geo-radar differential global positioning systems) techniques and characterization analyses (e.g. water absorption, permeability, open porosity or porosity accessible to water) to assess their morphological, physico-chemical, mechanical and hydric weathering; consolidation products or

  19. Sustainability Indicators for Chemical Processes: III. Biodiesel Case Study

    Science.gov (United States)

    The chemical industry is one of the most important business sectors, not only economically, but also societally; as it allows humanity to attain higher standards and quality of life. Simultaneously, chemical products and processes can be the origin of potential human health and ...

  20. Chemical interaction matrix between reagents in a Purex based process

    International Nuclear Information System (INIS)

    The United States Department of Energy (DOE) is the responsible entity for the disposal of the United States excess weapons grade plutonium. DOE selected a PUREX-based process to convert plutonium to low-enriched mixed oxide fuel for use in commercial nuclear power plants. To initiate this process in the United States, a Mixed Oxide (MOX) Fuel Fabrication Facility (MFFF) is under construction and will be operated by Shaw AREVA MOX Services at the Savannah River Site. This facility will be licensed and regulated by the U.S. Nuclear Regulatory Commission (NRC). A PUREX process, similar to the one used at La Hague, France, will purify plutonium feedstock through solvent extraction. MFFF employs two major process operations to manufacture MOX fuel assemblies: (1) the Aqueous Polishing (AP) process to remove gallium and other impurities from plutonium feedstock and (2) the MOX fuel fabrication process (MP), which processes the oxides into pellets and manufactures the MOX fuel assemblies. The AP process consists of three major steps, dissolution, purification, and conversion, and is the center of the primary chemical processing. A study of process hazards controls has been initiated that will provide knowledge and protection against the chemical risks associated from mixing of reagents over the life time of the process. This paper presents a comprehensive chemical interaction matrix evaluation for the reagents used in the PUREX-based process. Chemical interaction matrix supplements the process conditions by providing a checklist of any potential inadvertent chemical reactions that may take place. It also identifies the chemical compatibility/incompatibility of the reagents if mixed by failure of operations or equipment within the process itself or mixed inadvertently by a technician in the laboratories. (authors)

  1. Chemical kinetics, stochastic processes, and irreversible thermodynamics

    CERN Document Server

    Santillán, Moisés

    2014-01-01

    This book brings theories in nonlinear dynamics, stochastic processes, irreversible thermodynamics, physical chemistry, and biochemistry together in an introductory but formal and comprehensive manner.  Coupled with examples, the theories are developed stepwise, starting with the simplest concepts and building upon them into a more general framework.  Furthermore, each new mathematical derivation is immediately applied to one or more biological systems.  The last chapters focus on applying mathematical and physical techniques to study systems such as: gene regulatory networks and ion channels. The target audience of this book are mainly final year undergraduate and graduate students with a solid mathematical background (physicists, mathematicians, and engineers), as well as with basic notions of biochemistry and cellular biology.  This book can also be useful to students with a biological background who are interested in mathematical modeling, and have a working knowledge of calculus, differential equatio...

  2. Quaternary climate modulation of Pb isotopes in the deep Indian Ocean linked to the Himalayan chemical weathering

    Digital Repository Service at National Institute of Oceanography (India)

    Wilson, D.J.; Galy, A.; Piotrowski, A.M.; Banakar, V.K.

    ; enderson and Maier-Reimer, 2002), its isotopic composition is pected to be particularly sensitive to local weathering inputs. ad isotope measurements on the authigenic fraction of marine diments have therefore been used to trace regional weathering...., 2006) (Fig. 1). Materials and methods 1. Sampling and age models Lead isotopes were measured on bulk sediment acid-reductive achates at 94 depths between 8–518 cm (5–251 ka BP) in core 129-CR2 (i.e. an average sampling resolution of ∼3 kyr...

  3. Chemical Processing Department monthly report for August 1959

    Energy Technology Data Exchange (ETDEWEB)

    1959-09-21

    This report, from the Chemical Processing Department at HAPO, discusses the following: Production operation; Purex and Redox operation; Finished products operation; maintenance; Financial operations; facilities engineering; research; and employee relations.

  4. Chemical Processing Department monthly report for August 1958

    Energy Technology Data Exchange (ETDEWEB)

    1958-09-22

    This report, for August 1958 from the Chemical Processing Department at HAPO, discusses the following: Production operation; Purex and Redox operation; Finished products operation; maintenance; Financial operation; facilities engineering; research; and employee relations.

  5. Chemical Processing Department monthly report for February 1957

    Energy Technology Data Exchange (ETDEWEB)

    1957-03-21

    This report from the Chemical Processing Department at HAPO, discusses the following: Production operation, purex operation, redox operation, finished products operation, power and general maintenance operation, financial operation, facilities engineering operation, research and engineering operation, and employee relations operation.

  6. Chemical Processing Department monthly report for February 1959

    Energy Technology Data Exchange (ETDEWEB)

    1959-03-20

    This report for February 1959, from the Chemical Processing Department at HAPO, discusses the following: Production operation; Purex and Redox operation; Finished products operation; maintenance: Financial operations; facilities engineering; research; and employee relations.

  7. Chemical Processing Department monthly report for July 1957

    Energy Technology Data Exchange (ETDEWEB)

    McCune, F. K.; Johnson, W. E.; MacCready, W. K.; Warren, J. H.; Schroeder, O. C.; Groswith, C. T.; Mobley, W. N.; LaFollette, T. G.; Grim, K. G.; Shaw, H. P.; Richards, R. B.; Roberts, D. S.

    1957-08-22

    This report, for July 1957 from the Chemical Processing Department at HAPO, discusses the following; Production operation; Purex and Redox operation; Finished products operation; maintenance; Financial operations; facilities engineering; research; and employee relations.

  8. Chemical Processing Department monthly report for September 1962

    Energy Technology Data Exchange (ETDEWEB)

    1962-10-23

    This report, for September 1962 from the Chemical Processing Department at HAPO, discusses the following; Production operation; Purex and Redox operation; Finished products operation; maintenance; Financial operations; facilities engineering; research; and employee relations.

  9. Chemical Processing Department monthly report for September 1963

    Energy Technology Data Exchange (ETDEWEB)

    1963-10-21

    This report, from the Chemical Processing Department at HAPO for September 1963, discusses the following: Production operation; Purex and Redox operation; Finished products operation; maintenance; Financial operations, facilities engineering; research; employee relations; weapons manufacturing operation; and power and crafts operation.

  10. Chemical Processing Department monthly report for July 1964

    Energy Technology Data Exchange (ETDEWEB)

    1964-08-21

    This report, for July 1964 from the Chemical Processing Department at HAPO, discusses the following: Production operation; Purex and Redox operation; Finished products operation; maintenance; Financial operations; facilities engineering; research; employee relations; weapons manufacturing operation; and safety and security.

  11. Major ion chemistry of the Ganga-Brahmaputra river system: Weathering processes and fluxes to the Bay of Bengal

    Energy Technology Data Exchange (ETDEWEB)

    Sarin, M.M.; Krishnaswami, S.; Dilli, K.; Somayajulu, B.L.K. (Physical Research Laboratory, Ahmedabad (India)); Moore, W.S. (Univ. of South Carolina (USA))

    1989-05-01

    The Ganga-Brahmaputra, one of the worlds's largest river systems, is first in terms of sediment transport and fourth in terms of water discharge. A detailed and systematic study of the major ion chemistry of these rivers and their tributaries, as well as the clay mineral composition of the bed sediments has been conducted. The chemistry of the highland rivers are all dominated by carbonate weathering; (Ca + Mg) and HCO{sub 3} account for about 80% of the cations and anions. In the lowland rivers, HCO{sub 3} excess over (Ca + Mg) and a relatively high contribution of (Na + K) to the total cations indicate that silicate weathering and/or contributions from alkaline/saline soils and ground waters could be important sources of major ions to these waters. The chemistry of the Ganga and the Yamuna in the lower reaches is by and large dictated by the chemistry of their tributaries and their mixing proportions. The highland rivers weather acidic rocks, whereas the others flow initially through basic effusives. The Ganga-Brahmaputra river system transports about 130 million tons of dissolved salts to the Bay of Bengal, which is nearly 3% of the global river flux to the oceans. The chemical denudation rates for the Ganga and the Brahmaputra basins are about 72 and 105 tons{center dot}km{sup {minus}2}{center dot}yr{sup {minus}1}, respectively, which are factors of 2 to 3 higher than the global average. The high denudation rate, particularly in the Brahmaputra, is attributable to high relief and heavy rainfall.

  12. Chemical grouting process for tight soil

    Energy Technology Data Exchange (ETDEWEB)

    Doyle, E.H.; Kauffman, D.; Herce, J.A.

    1975-07-15

    A process is described for strengthening a soil in which the pores are too small to be penetrated by a slurry of cement. A means for injecting fluid is arranged for flowing fluid into a selected zone within such a soil formation at a rate such that the fluid velocity in the pores in that zone is at least 0.3 cm per min. A determination is made of the extent of time-temperature exposure to which a fluid is subjected when it flows at the selected rate from a fluid-compounding location to the selected zone within the soil formation. A basic aqueous solution of an amphoteric metal oxide and a pH-reducing reactant that begins precipitating a hydrated metal oxide after being subjected to the determined extent of time-temperature exposure is prepared at the fluid-compounding location. The prepared solution is flowed into the selected zone at the selected rate while the time and the temperature conditions of the compounding and storing of the fluid are adjusted so that substantially all portions of the solution are subjected to the determined extent of time-temperature exposure. (9 claims)

  13. Chemical Processing Department monthly report, March 1959

    Energy Technology Data Exchange (ETDEWEB)

    1959-04-20

    Production of Pu, UO{sub 3}, and Pu metal exceeded forecasts. The 2nd attempt at Purex to recover Zr-Nb resulted in about 1/3 recovery, contaminated with about 1% of the Ce. Palm losses to Purex U product were eliminated, and the Pu content was reduced 5 to 10{times}. Routing the dissolver rinses into 3WB concentrator resulted into improved rinsing efficiency. Unclarified feed was processed through Purex HA column. In a test for using B in Redox, the B was routed completely to the waste; it was not detectable in product streams beyond the first cycle. Almost 1000 g Palm was purified and converted to oxide. Ferrous ion catalyzed the reduction of Palm VI by hydrazine or semicarbazide. Coordination of E-metal and NPR reprocessing at Redox in multipurpose dissolver was studied. An interim fission product recovery program at Purex will be directed toward low-efficiency collection of Pm {sup 147}. Locations for critical incident alarms were selected. (DLC)

  14. Analysis of chemical coal cleaning processes. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1980-06-01

    Six chemical coal cleaning processes were examined. Conceptual designs and costs were prepared for these processes and coal preparation facilities, including physical cleaning and size reduction. Transportation of fine coal in agglomerated and unagglomerated forms was also discussed. Chemical cleaning processes were: Pittsburgh Energy Technology Center, Ledgemont, Ames Laboratory, Jet Propulsion Laboratory (two versions), and Guth Process (KVB). Three of the chemical cleaning processes are similar in concept: PETC, Ledgemont, and Ames. Each of these is based on the reaction of sulfur with pressurized oxygen, with the controlling factor being the partial pressure of oxygen in the reactor. All of the processes appear technically feasible. Economic feasibility is less certain. The recovery of process chemicals is vital to the JPL and Guth processes. All of the processes consume significant amounts of energy in the form of electric power and coal. Energy recovery and increased efficiency are potential areas for study in future more detailed designs. The Guth process (formally designed KVB) appears to be the simplest of the systems evaluated. All of the processes require future engineering to better determine methods for scaling laboratory designs/results to commercial-scale operations. A major area for future engineering is to resolve problems related to handling, feeding, and flow control of the fine and often hot coal.

  15. Chemicals in the process chain from raw material to product

    International Nuclear Information System (INIS)

    As described in this presentation, chemicals are added at various points along the physical flow from oil/gas well to sold products. They have several functions and are added in different amounts. The chemicals may have a negative impact on the environment by emission to sea. But they can also reduce the regularity of the processing equipment and the prices of the products. Therefore, Statoil has begun a research project that aims to develop improved methods and tools for the prediction of the distribution of chemicals in the process chain and the unwanted effects they might have on the environment, on downstream installations and on the products. 4 refs., 11 figs

  16. Neutron radiography and X-ray computed tomography for quantifying weathering and water uptake processes inside porous limestone used as building material

    International Nuclear Information System (INIS)

    Euville and Savonnières limestones were weathered by acid test and this resulted in the formation of a gypsum crust. In order to characterize the crystallization pattern and the evolution of the pore structure below the crust, a combination of high resolution X-ray computed tomography and SEM–EDS was used. A time lapse sequence of the changing pore structure in both stones was obtained and afterwards quantified by using image analysis. The difference in weathering of both stones by the same process could be explained by the underlying microstructure and texture. Because water and moisture play a crucial role in the weathering processes, water uptake in weathered and non-weathered samples was characterized based on neutron radiography. In this way the water uptake was both visualized and quantified in function of the height of the sample and in function of time. In general, the formation of a gypsum crust on limestone slows down the initial water uptake in the materials. - Highlights: • Time lapse sequence in 3D of changing pore structures inside limestone • A combination of X-ray CT, SEM and neutron radiography was used. • Quantification of water content in function of time, height and weathering • Characterization of weathering processes due to gypsum crystallization

  17. Geochemistry of river-borne clays entering the East China Sea indicates two contrasting types of weathering and sediment transport processes

    Science.gov (United States)

    Bi, Lei; Yang, Shouye; Li, Chao; Guo, Yulong; Wang, Quan; Liu, James T.; Yin, Ping

    2015-09-01

    The East China Sea is characterized by wide continental shelf receiving a huge input of terrigenous matter from both large rivers and mountainous rivers, which makes it an ideal natural laboratory for studying sediment source-to-sink transport processes. This paper presents mineralogical and geochemical data of the clays and bulk sediments from the rivers entering the East China Sea, aiming to investigate the general driving mechanism of silicate weathering and sediment transport processes in East Asian continental margin. Two types of river systems, tectonically stable continental rivers and tectonically active mountainous rivers, coexist in East Asia. As the direct weathering products, clays can better reflect the silicate weathering regimes within the two river systems. Provenance rock types are not the dominant factor causing silicate weathering intensity difference existed in the East Asian rivers. The silicate weathering intensity of tectonically stable river basins is primarily driven by monsoon climate, and the sediment transfer is relatively slow because of natural trapping process and increasing damming effect. The geochemistry of these river-borne sediments can thus indicate paleo-weathering intensities in East Asian continent. In contrast, silicate weathering intensity in tectonically active mountainous rivers is greatly limited by strong physical erosion despite the high temperature and highest monsoon rainfall. The factors controlling silicate weathering in tectonically active catchments are complex and thus, it should be prudent to use river sediment records to decipher paleoclimate change. These two different silicate weathering regimes and sediment transport processes are manifestations of the landscape evolution and overall dominate the sedimentation in Asian continental margin.

  18. Evidence for mechanical and chemical alteration of iron-nickel meteorites on Mars: Process insights for Meridiani Planum

    Science.gov (United States)

    Ashley, James W.; Golombek, M.P.; Christensen, P.R.; Squyres, S. W.; McCoy, T.J.; Schroder, C.; Fleischer, I.; Johnson, J. R.; Herkenhoff, K. E.; Parker, T.J.

    2011-01-01

    The weathering of meteorites found on Mars involves chemical and physical processes that can provide clues to climate conditions at the location of their discovery. Beginning on sol 1961, the Opportunity rover encountered three large iron meteorites within a few hundred meters of each other. In order of discovery, these rocks have been assigned the unofficial names Block Island, Shelter Island, and Mackinac Island. Each rock presents a unique but complimentary set of features that increase our understanding of weathering processes at Meridiani Planum. Significant morphologic characteristics interpretable as weathering features include (1) a large pit in Block Island, lined with delicate iron protrusions suggestive of inclusion removal by corrosive interaction; (2) differentially eroded kamacite and taenite lamellae in Block Island and Shelter Island, providing relative timing through crosscutting relationships with deposition of (3) an iron oxide-rich dark coating; (4) regmaglypted surfaces testifying to regions of minimal surface modification, with other regions in the same meteorites exhibiting (5) large-scale, cavernous weathering (in Shelter Island and Mackinac Island). We conclude that the current size of the rocks is approximate to their original postfall contours. Their morphology thus likely results from a combination of atmospheric interaction and postfall weathering effects. Among our specific findings is evidence supporting (1) at least one possible episode of aqueous acidic exposure for Block Island; (2) ripple migration over portions of the meteorites; (3) a minimum of two separate episodes of wind abrasion; alternating with (4) at least one episode of coating-forming chemical alteration, most likely at subzero temperatures. Copyright 2011 by the American Geophysical Union.

  19. Dust as interstellar catalyst. I. Quantifying the chemical desorption process

    Science.gov (United States)

    Minissale, M.; Dulieu, F.; Cazaux, S.; Hocuk, S.

    2016-01-01

    Context. The presence of dust in the interstellar medium has profound consequences on the chemical composition of regions where stars are forming. Recent observations show that many species formed onto dust are populating the gas phase, especially in cold environments where UV- and cosmic-ray-induced photons do not account for such processes. Aims: The aim of this paper is to understand and quantify the process that releases solid species into the gas phase, the so-called chemical desorption process, so that an explicit formula can be derived that can be included in astrochemical models. Methods: We present a collection of experimental results of more than ten reactive systems. For each reaction, different substrates such as oxidized graphite and compact amorphous water ice were used. We derived a formula for reproducing the efficiencies of the chemical desorption process that considers the equipartition of the energy of newly formed products, followed by classical bounce on the surface. In part II of this study we extend these results to astrophysical conditions. Results: The equipartition of energy correctly describes the chemical desorption process on bare surfaces. On icy surfaces, the chemical desorption process is much less efficient, and a better description of the interaction with the surface is still needed. Conclusions: We show that the mechanism that directly transforms solid species into gas phase species is efficient for many reactions.

  20. Changes in soil chemical properties and lettuce yield response following incorporation of biochar and cow dung to highly weathered acidic soils

    DEFF Research Database (Denmark)

    Agyei Frimpong, Kwame; Amoakwah, Emmanuel; Osei, Benjamin;

    2016-01-01

    imposed on two highly weathered, acidic soils from the coastal savanna and tropical rainforest agroecological zones of Ghana, respectively, to elucidate their effect on yield of lettuce. The study showed that application of biochar solely or in combination with cow dung increased soil pH, total organic...... carbon, and cation exchange capacity, and temporarily increased soil respiration and microbial biomass carbon. Further, incorporation of combined application of cow dung and biochar increased lettuce yield more than sole incorporation of either amendment. The study demonstrated that corn cob biochar can...... improve soil chemical properties and lettuce yield if applied solely or in combination with cow dung....

  1. An Extended Algorithm of Flexibility Analysis in Chemical Engineering Processes

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    An extended algorithm of flexibility analysis with a local adjusting method for flexibility region of chemical processes, which is based on the active constraint strategy, is proposed, which fully exploits the flexibility region of the process system operation. The hyperrectangular flexibility region determined by the extended algorithm is larger than that calculated by the previous algorithms. The limitation of the proposed algorithm due to imperfect convexity and its corresponding verification measure are also discussed. Both numerical and actual chemical process examples are presented to demonstrate the effectiveness of the new algorithm.

  2. Chemical Processing Department monthly report for October 1956

    Energy Technology Data Exchange (ETDEWEB)

    1956-11-21

    The October, 1956 monthly report for the Chemical Processing Department of the Hanford Atomic Products Operation includes information regarding research and engineering efforts with respect to the Purex and Redox process technology. Also discussed is the production operation, finished product operation, power and general maintenance, financial operation, engineering and research operations, and employee operation. (MB)

  3. Chemical Processing Department monthly report for September 1958

    Energy Technology Data Exchange (ETDEWEB)

    1958-10-22

    The September, 1958 monthly report for the Chemical Processing Department of the Hanford Atomic Products Operation includes information regarding research and engineering efforts with respect to the Purex and Redox process technology. Also discussed is the production operation, finished product operation, power and general maintenance, financial operation, engineering and research operations, and employee operation. (MB)

  4. Diffusion mechanisms for chemical-thermal metal processing

    International Nuclear Information System (INIS)

    To describe volumetric diffusion in metals, some possible mechanisms are offered: exchange, cyclic (circular), interstitial idle time and interstitial with cumulative and vacancy replacement. It is revealed that at chemical-thermal processing the diffusion process is complex where there is multidimensional movement of atoms and displacement of crystal lattices

  5. MICROSTRUCTURE DEVICES FOR APPLICATIONS IN THERMAL AND CHEMICAL PROCESS ENGINEERING

    OpenAIRE

    Brandner, Juergen; Anurjew, E.; Henning, T.; Schygulla, U.; Schubert, K.

    2006-01-01

    In this publication, an overview of the work dealing with thermal and chemical micro process engineering performed at the Institute for Micro Process Engineering (IMVT) of Forschungszentrum Karlsruhe will be given. The focus will be set on manufacturing of metallic microstructure devices and on microstructure heat exchangers. A brief outlook will describe possible future application fields.

  6. A Course in Project Evaluation in the Chemical Process Industries.

    Science.gov (United States)

    Valle-Riestra, J. Frank

    1983-01-01

    Describes a course designed to expose neophytes to methodology used in chemical process industries to evaluate commercial feasibility of proposed projects. Previously acquired disciplines are integrated to facilitate process synthesis, gain appreciation of nature of industrial projects and industrial viewpoint in managing them, and to become adept…

  7. Dust as interstellar catalyst I. Quantifying the chemical desorption process

    CERN Document Server

    Minissale, M; Cazaux, S; Hocuk, S

    2015-01-01

    Context. The presence of dust in the interstellar medium has profound consequences on the chemical composition of regions where stars are forming. Recent observations show that many species formed onto dust are populating the gas phase, especially in cold environments where UV and CR induced photons do not account for such processes. Aims. The aim of this paper is to understand and quantify the process that releases solid species into the gas phase, the so-called chemical desorption process, so that an explicit formula can be derived that can be included into astrochemical models. Methods. We present a collection of experimental results of more than 10 reactive systems. For each reaction, different substrates such as oxidized graphite and compact amorphous water ice are used. We derive a formula to reproduce the efficiencies of the chemical desorption process, which considers the equipartition of the energy of newly formed products, followed by classical bounce on the surface. In part II we extend these resul...

  8. The National Toxicology Program chemical nomination selection and testing process.

    Science.gov (United States)

    Heindel, J J

    1988-01-01

    The NTP is an interagency program of the Federal Government which coordinates toxicological programs at the NIH (NIEHS), FDA (NCTR), and CDC (NIOSH) with input from NCI, NIH, OSHA, CPSC, EPA, and ATSDR. The NTP has the capability to completely characterize the toxicologic profile of a chemical, including studies of chemical disposition, genetic toxicity, immunotoxicity, teratology, reproductive toxicity, carcinogenicity, neurotoxicity, and specific organ toxicity. The NTP encourages nominations of chemicals of human health concern from all sectors of the public, including industry, labor, and the general public. The specific process of nomination, evaluation, and selection of chemicals for testing by the NTP is described. It is a multicomponent system with several evaluations and a public peer review step to assure adequate consideration of all nominated chemicals. The results of NTP studies are all peer reviewed and available to the general public as well as to the scientific community. PMID:2980357

  9. Chemical sensors and gas sensors for process control in biotechnology

    International Nuclear Information System (INIS)

    This paper is concerned with the possibilities for chemical measurement of the progress of biotechnological processes which are offered by devices already developed for other demanding applications. It considers the potential use of ultrasonic instrumentation originally developed for the nuclear industry, gas measurement methods from the fields of environmental monitoring and combustion control, nuclear instruments developed for the oil, mining and chemical industries, robotic systems and advanced control techniques. (author)

  10. A chemical process of asphaltenes dispersion : anticor DSA 700

    International Nuclear Information System (INIS)

    This work deals with asphalts dispersion chemical process. Asphaltenes are constituents of petroleum which under chemical, physical or mechanical variations effect precipitate and create deposits. In order to cope with this problem, a product : Anticor DSA 700 has been adjusted and allow to stabilize asphaltenes. This method has already been used in France and in Algeria and will be extended to others west countries. (O.L.). 2 figs

  11. Process Design and Evaluation for Chemicals Based on Renewable Resources

    DEFF Research Database (Denmark)

    Fu, Wenjing

    One of the key steps in process design is choosing between alternative technologies, especially for processes producing bulk and commodity chemicals. Recently, driven by the increasing oil prices and diminishing reserves, the production of bulk and commodity chemicals from renewable feedstocks has...... well as to match different catalyst conditions. These kinds of problems are crucial, especially at the early stages of process development, when information is limited. This thesis describes a methodological framework for dealing with the challenges and giving direction to research in the process...... process design of the synthesis 2,5-furandicarboxylic acid (FDA) from glucose. By using the selected case study, the complexity and challenges for the process engineer to choose between different alternative routes and technologies as well as to combine two different kinds of catalysis (enzymatic...

  12. Iron-based syngas chemical looping process and coal-direct chemical looping process development at Ohio State University

    International Nuclear Information System (INIS)

    Highlights: • Moving bed reducer maximizes solids conversion and maintains full fuel conversion. • 850+ Operating hours completed in 25-kWth sub-pilot chemical looping units. • Full solid and gaseous fuel conversion achieved in sub-pilot chemical looping units. • Fully integrated, pressurized 250-kWth pilot SCL unit construction initiated. • Extensive techno-economic analysis performed on CDCL and SCL process configurations. - Abstract: The increasing demands for energy and concern of global warming are intertwined issues of critical importance. With the pressing need for clean, efficient, and cost-effective energy conversion processes, the chemical looping strategy has evolved as a promising alternative to the traditional carbonaceous fuel conversion processes. Chemical looping processes utilize oxygen carrier particles to indirectly convert carbonaceous fuels while capturing CO2 for sequestration and/or utilization. Throughout its development, multiple oxygen carrier compositions and reactor configurations have been studied and demonstrated. The Ohio State University (OSU) chemical looping technologies have received significant attention over the recent years. OSU’s unique moving-bed chemical looping technologies coupled with iron-based oxygen carrier particles capable of sustaining hundreds of redox cycles have the advantage of converting a variety of carbonaceous fuels, such as natural gas, coal and biomass, to electricity, H2, liquid fuels, or any combination thereof with zero to negative net CO2 emissions. Specifically, two chemical looping processes are being developed and studied, the syngas chemical looping (SCL) and the coal direct chemical looping (CDCL) technologies. Over the past 14 years, these processes have developed from a novel concept to successful sub-pilot (25 kWth) demonstrations. With the support of the Advanced Research Projects Agency – Energy (ARPA-E) of the US Department of Energy (USDOE), a 250 kWth high pressure SCL pilot

  13. Simulation of long term atmospheric corrosion process on plain and weathering steels

    International Nuclear Information System (INIS)

    Information on weathering steel behaviour and its rust products characteristics after decades of atmospheric exposure are scarce. On the other side, generally accepted laboratory tests for the assessment of its corrosion resistance have not been developed yet. Consequently, simulating corrosion in the laboratory during long periods of time are attractive for the interesting and complete information obtainable from them. In the present work, AISI-SAE 1008 and ASTM-588 B steel samples have been exposed for two years to a immersion-emersion CEBELCOR type test in the laboratory, simulating a moderate urban atmosphere. Two groups of six samples each were tested. After the first year, three samples of each batch were retired for analysis and the rest was kept until they reached two years of exposure. The half cell electrode potentials were measured daily. The rust was characterized by metallographic techniques, Moessbauer spectroscopy (MS). Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). Comparison was done with field exposure experiments reported in the literature, and conclusions on the behaviour of tested samples were drawn looking for differences and similarities with samples and structures under actual atmospheric conditions. (Author) 15 refs

  14. Treatment Process Requirements for Waters Containing Hydraulic Fracturing Chemicals

    Science.gov (United States)

    Stringfellow, W. T.; Camarillo, M. K.; Domen, J. K.; Sandelin, W.; Varadharajan, C.; Cooley, H.; Jordan, P. D.; Heberger, M. G.; Reagan, M. T.; Houseworth, J. E.; Birkholzer, J. T.

    2015-12-01

    A wide variety of chemical additives are used as part of the hydraulic fracturing (HyF) process. There is concern that HyF chemicals will be released into the environment and contaminate drinking water, agricultural water, or other water used for beneficial purposes. There is also interest in using produced water (water extracted from the subsurface during oil and gas production) for irrigation and other beneficial purposes, especially in the arid Southwest US. Reuse of produced water is not speculative: produced water can be low in salts and is being used in California for irrigation after minimal treatment. In this study, we identified chemicals that are used for hydraulic fracturing in California and conducted an analysis to determine if those chemicals would be removed by a variety of technically available treatment processes, including oil/water separation, air stripping, a variety of sorption media, advanced oxidation, biological treatment, and a variety of membrane treatment systems. The approach taken was to establish major physiochemical properties for individual chemicals (log Koc, Henry's constant, biodegradability, etc.), group chemicals by function (e.g corrosion inhibition, biocides), and use those properties to predict the fate of chemical additives in a treatment process. Results from this analysis is interpreted in the context of what is known about existing systems for the treatment of produced water before beneficial reuse, which includes a range of treatment systems from oil/water separators (the most common treatment) to sophisticated treatment trains used for purifying produced water for groundwater recharge. The results show that most HyF chemical additives will not be removed in existing treatment systems, but that more sophisticated treatment trains can be designed to remove additives before beneficial reuse.

  15. Chemical precipitation processes for the treatment of aqueous radioactive waste

    International Nuclear Information System (INIS)

    Chemical precipitation by coagulation-flocculation and sedimentation has been commonly used for many years to treat liquid (aqueous) radioactive waste. This method allows the volume of waste to be substantially reduced for further treatment or conditioning and the bulk of the waste to de discharged. Chemical precipitation is usually applied in combination with other methods as part of a comprehensive waste management scheme. As with any other technology, chemical precipitation is constantly being improved to reduce cost to increase the effectiveness and safety on the entire waste management system. The purpose of this report is to review and update the information provided in Technical Reports Series No. 89, Chemical Treatment of Radioactive Wastes, published in 1968. In this report the chemical methods currently in use for the treatment of low and intermediate level aqueous radioactive wastes are described and illustrated. Comparisons are given of the advantages and limitations of the processes, and it is noted that good decontamination and volume reduction are not the only criteria according to which a particular process should be selected. Emphasis has been placed on the need to carefully characterize each waste stream, to examine fully the effect of segregation and the importance of looking at the entire operation and not just the treatment process when planning a liquid waste treatment facility. This general approach includes local requirements and possibilities, discharge authorization, management of the concentrates, ICRP recommendations and economics. It appears that chemical precipitation process and solid-liquid separation techniques will continue to be widely used in liquid radioactive waste treatment. Current research and development is showing that combining different processes in one treatment plant can provide higher decontamination factors and smaller secondary waste arisings. Some of these processes are already being incorporated into new and

  16. The Wegener-Bergeron-Findeisen process – Its discovery and vital importance for weather and climate

    Directory of Open Access Journals (Sweden)

    Trude Storelvmo

    2015-04-01

    Full Text Available The Wegener-Bergeron-Findeisen process refers to the rapid growth of ice crystals at the expense of surrounding cloud droplets, which frequently occurs in atmospheric mixed-phase clouds. The process is a result of the difference in saturation vapor pressures with respect to liquid and ice, and may in some circumstances lead to abrupt and complete cloud glaciation at temperatures between −40 °C and 0 °C in the Earth's atmosphere. The process is named after three eminent scientists who were active in the first half of the 20th century, among them being German meteorologist Walter Findeisen (1909–1945. In his classical paper published in 1938, Findeisen described the contemporary understanding of the Wegener-Bergeron-Findeisen process and other key cloud microphysical processes. Here, we compare the understanding of the aforementioned processes at the time with that of the present, and find that they are remarkably similar. We also discuss how the Wegener-Bergeron-Findeisen process is implemented in state-of-the-art numerical models of the atmosphere, and highlight its importance for both weather and climate.

  17. Electrochemistry and green chemical processes: electrochemical ozone production

    Directory of Open Access Journals (Sweden)

    Leonardo M. da Silva

    2003-12-01

    Full Text Available After an introductory discussion emphasising the importance of electrochemistry for the so-called Green Chemical Processes, the article presents a short discussion of the classical ozone generation technologies. Next a revision of the electrochemical ozone production technology focusing on such aspects as: fundamentals, latest advances, advantages and limitations of this technology is presented. Recent results about fundamentals of electrochemical ozone production obtained in our laboratory, using different electrode materials (e.g. boron doped diamond electrodes, lead dioxide and DSAÒ-based electrodes also are presented. Different chemical processes of interest to the solution of environmental problems involving ozone are discussed.

  18. The effect of light rare earths on the chemical durability and weathering of Na2O-CaO-SiO2 glasses

    International Nuclear Information System (INIS)

    In this paper, the investigation on chemical durability and weathering of soda-lime-silicate glasses containing light rare earths (La, Ce and Nd) prepared with traditional melt-quenching methods was carried out by ICP-AES, optical microscopy, SEM and EDS. The weight losses of different glasses in different attacking media were measured, and the normalized releases were calculated. The results showed that the presence of La, Ce and Nd increased the water resistance of glasses and decreased the normalized releases of silicon. The addition of La and Nd improved the acid and alkaline resistance of glass; however, the effect of Ce was opposite. The results of weathering of glasses agree well with experimental data of chemical durability. Comparing with Nd-dopes glass, white plate crystals on the surfaces of undoped, La-dopes and Ce-doped glass were observed, moreover, isolated pits of 0.5-2.0 μm on the surface of Ce-doped glass appeared.

  19. Mobility of major and trace elements in andosols from Iceland: correlating extent of chemical weathering with climatic conditions at soil formation sites

    Science.gov (United States)

    Oskarsson, Birgir V.; Riishuus, Morten S.; Arnalds, Olafur

    2010-05-01

    Element mobility within volcanic soil profiles developed in diverse climatic conditions in Iceland is assessed. Soils were selected from areas with good monitoring of annual temperature and precipitation and the degree of weathering and elemental behavior was compared. Most soils in Iceland develop in parent materials of volcanic origin, including a variety of basaltic and andesitic tephras, hyaloclastites and glacial tillites. Most Icelandic soils are subject to considerable flux of eolian deposition and in times receive tephra ejecta from volcanic eruptions. In this study, samples were carefully extracted from brown and gleyic andosol horizons for major and trace element analysis. Each horizon is representative of a pedogenetic stage. Preliminary results show that the major elements TiO2, Al2O3 and Fe2O3 (T) (mean wt% = 3.4, 19.2, 17.3) appear immobile relative to the parent material (p.m. mean wt% = 1.6, 14.6, 10.9) and are found enriched within more mature horizons. The base cations MgO, CaO and Na2O (mean wt% = 4.11, 7.23, 1.8) are depleted in these horizons (p.m. mean wt% = 9.1, 11.8, 2.0) showing mobilization during pedogenesis. The trace elements reveal no strong enrichment/depletion trend with a range of mobility from mobile to immobile Rb, Zn, Y, Sr, Ba, Ni, La, Cr, Cu, Nd, V, Zr and Nb. Soils developed in colder and dryer climatic conditions in Iceland (MAT = -1°C and MAP = 1000mm) show higher levels of weathering (CIA-K = 50-65) and element mobilization. The parent materials have a CIA-K weathering index of 37. The relationship of the covariance of the climate parameters with extent of chemical weathering may be quantified as climofunctions to deliver proxy climate data under cool to subarctic conditions. Our results may yield reasonable tools for determining past climate variations from weathered tephras found as paleosols in the Neogene lava piles of Iceland and other volcanic provinces.

  20. Integrating chemical engineering fundamentals in the capstone process design project

    DEFF Research Database (Denmark)

    von Solms, Nicolas; Woodley, John; Johnsson, Jan Erik;

    2010-01-01

    All B.Eng. courses offered at the Technical University of Denmark (DTU) must now follow CDIO standards. The final “capstone” course in the B.Eng. education is Process Design, which for many years has been typical of chemical engineering curricula worldwide. The course at DTU typically has about 30...... receive. The education is designed to provide students with the necessary tools to become productive in a company in a short time – so there is a strong industrial focus. Some students choose to continue with their studies and can then complete an M.Sc. after a further two years of study. The demands of...... chemical plants will incorporate one or more chemical reactors. In the initial stages of a process design, it is sufficient to express simply the reactor inputs and outputs. However in later stages, details about the reactor need to be specified. This is only possible using tools learned in the course...

  1. Chemical and physicochemical characteristics changes during passion fruit juice processing

    Directory of Open Access Journals (Sweden)

    Aline Gurgel Fernandes

    2011-09-01

    Full Text Available Passion fruit is widely consumed due to its pleasant flavour and aroma acidity, and it is considered very important a source of minerals and vitamins. It is used in many products such as ice-cream, mousses and, especially, juices. However, the processing of passion fruit juice may modify the composition and biodisponibility of the bioactive compounds. Investigations of the effects of processing on nutritional components in tropical juices are scarce. Frequently, only losses of vitamin C are evaluated. The objective of this paper is to investigate how some operations of passion fruit juice processing (formulation/homogeneization/thermal treatment affect this product's chemical and physicochemical characteristics. The results showed that the chemical and physicochemical characteristics are little affected by the processing although a reduction in vitamin C contents and anthocyanin, large quantities of carotenoids was verified even after the pasteurization stage.

  2. IAEA coordinated research project (CRP). The use of selected safety indicators (concentrations, fluxes) in the assessment of radioactive waste disposal. Report 5: Chemical weathering rates on the Baltic Shield of Finland for use as indicators of nuclear waste repository safety

    International Nuclear Information System (INIS)

    In this report the available information from the literature on chemical erosion and weathering rates in Finland and northern Sweden is reviewed and experimental data from recent followup studies in defined catchments is discussed. In glaciated terrain as in Finland the best estimates of chemical erosion rates are obtained when geochemical data of glacial till is used. Elemental fluxes in free-flowing rivers and river-lake systems have been studied in greater detail only in a few case studies. The Kalix river drainage basin investigations gave evidence that the mobilization of rare earth elements (REE) is determined by weathering processes in the upper till layers and that the C-horizon below about 0.75 m depth or generally below the groundwater table is practically unaffected by weathering. Also the removal of U from the watershed was found to happen mostly by groundwater flow through predominantly shallow aquifers. Another type of case study is constrained to regions where certain phenomena cause enhanced trace metal mobilization, as in a region stretched along the western coast of Finland where land-uplift exposes clay sediments rich in sulphides above the groundwater level, with the consequence of increased mobilization of a number of heavy metals. Very little quantitative information on elemental flux balances is available from river-lake systems. Some modelling has been attempted on one great lake system the lake Paeijaenne by use of fall-out nuclides. From the same lake a detailed record of sedimentation rates covering the whole period from the end of the latest glaciation to present is available and erosion rate variations since the end of the latest glaciation can be assessed. The main part of this study focusses on investigations of well-defined small catchments over a longer time period, where groundwater is discharging in springs. Geochemical fluxes worth mentioning seem to be constrained to the surficial geological layers which include overburden and

  3. Utilization of Live Localized Weather Information for Sustainable Agriculture

    Science.gov (United States)

    Anderson, J.; Usher, J.

    2010-09-01

    Authors: Jim Anderson VP, Global Network and Business Development WeatherBug® Professional Jeremy Usher Managing Director, Europe WeatherBug® Professional Localized, real-time weather information is vital for day-to-day agronomic management of all crops. The challenge for agriculture is twofold in that local and timely weather data is not often available for producers and farmers, and it is not integrated into decision-support tools they require. Many of the traditional sources of weather information are not sufficient for agricultural applications because of the long distances between weather stations, meaning the data is not always applicable for on-farm decision making processes. The second constraint with traditional weather information is the timeliness of the data. Most delivery systems are designed on a one-hour time step, whereas many decisions in agriculture are based on minute-by-minute weather conditions. This is especially true for decisions surrounding chemical and fertilizer application and frost events. This presentation will outline how the creation of an agricultural mesonet (weather network) can enable producers and farmers with live, local weather information from weather stations installed in farm/field locations. The live weather information collected from each weather station is integrated into a web-enabled decision support tool, supporting numerous on-farm agronomic activities such as pest management, or dealing with heavy rainfall and frost events. Agronomic models can be used to assess the potential of disease pressure, enhance the farmer's abilities to time pesticide applications, or assess conditions contributing to yield and quality fluctuations. Farmers and industry stakeholders may also view quality-assured historical weather variables at any location. This serves as a record-management tool for viewing previously uncharted agronomic weather events in graph or table form. This set of weather tools is unique and provides a

  4. Model Based Monitoring and Control of Chemical and Biochemical Processes

    DEFF Research Database (Denmark)

    Huusom, Jakob Kjøbsted

    This presentation will give an overview of the work performed at the department of Chemical and Biochemical Engineering related to process control. A research vision is formulated and related to a number of active projects at the department. In more detail a project describing model estimation and...

  5. Portfolio Assessment on Chemical Reactor Analysis and Process Design Courses

    Science.gov (United States)

    Alha, Katariina

    2004-01-01

    Assessment determines what students regard as important: if a teacher wants to change students' learning, he/she should change the methods of assessment. This article describes the use of portfolio assessment on five courses dealing with chemical reactor and process design during the years 1999-2001. Although the use of portfolio was a new…

  6. Fabrication of agglomerate-free nanopowders by hydrothermal chemical processing

    OpenAIRE

    Schmidt, Helmut K.; Nass, Rüdiger; Burgard, Detlef; Nonninger, Ralph

    1998-01-01

    A chemical processing technique for the fabrication of nanopowders has been developed. The route is based on precipitation processes in solutions, either within aqueous droplets in microemulsions in the presence of surface modifiers like surfactants or by direct precipitation in solutions in the presence of theses surface modifiers or small organic molecules directly bonded to the particle surface. In order to obtain well crystallized or densified particles, a continuous flow hydrothermal pro...

  7. Data reconciliation and gross error detection: application in chemical processes

    OpenAIRE

    EGHBAL AHMADİ, Mohammad Hosein

    2015-01-01

    Abstract. Measured data are normally corrupted by different kinds of errors in many chemical processes. In this work, a brief overview in data reconciliation and gross error detection believed as the most efficient technique in reducing the measurement errors and obtaining accurate information about the process is presented. In addition to defining the basic problem and a survey of recent developments in this area that is categorized in “Real Time Optimization” field, we will describe about a...

  8. Fair weather atmospheric electricity

    International Nuclear Information System (INIS)

    Not long after Franklin's iconic studies, an atmospheric electric field was discovered in 'fair weather' regions, well away from thunderstorms. The origin of the fair weather field was sought by Lord Kelvin, through development of electrostatic instrumentation and early data logging techniques, but was ultimately explained through the global circuit model of C.T.R. Wilson. In Wilson's model, charge exchanged by disturbed weather electrifies the ionosphere, and returns via a small vertical current density in fair weather regions. New insights into the relevance of fair weather atmospheric electricity to terrestrial and planetary atmospheres are now emerging. For example, there is a possible role of the global circuit current density in atmospheric processes, such as cloud formation. Beyond natural atmospheric processes, a novel practical application is the use of early atmospheric electrostatic investigations to provide quantitative information on past urban air pollution.

  9. Influence of surface coverage on the chemical desorption process

    Energy Technology Data Exchange (ETDEWEB)

    Minissale, M.; Dulieu, F., E-mail: francois.dulieu@obspm.fr [LERMA, Université de Cergy Pontoise et Observatoire de Paris, UMR 8112 du CNRS. 5, mail Gay Lussac, 95031 Cergy Pontoise (France)

    2014-07-07

    In cold astrophysical environments, some molecules are observed in the gas phase whereas they should have been depleted, frozen on dust grains. In order to solve this problem, astrochemists have proposed that a fraction of molecules synthesized on the surface of dust grains could desorb just after their formation. Recently the chemical desorption process has been demonstrated experimentally, but the key parameters at play have not yet been fully understood. In this article, we propose a new procedure to analyze the ratio of di-oxygen and ozone synthesized after O atoms adsorption on oxidized graphite. We demonstrate that the chemical desorption efficiency of the two reaction paths (O+O and O+O{sub 2}) is different by one order of magnitude. We show the importance of the surface coverage: for the O+O reaction, the chemical desorption efficiency is close to 80% at zero coverage and tends to zero at one monolayer coverage. The coverage dependence of O+O chemical desorption is proved by varying the amount of pre-adsorbed N{sub 2} on the substrate from 0 to 1.5 ML. Finally, we discuss the relevance of the different physical parameters that could play a role in the chemical desorption process: binding energy, enthalpy of formation, and energy transfer from the new molecule to the surface or to other adsorbates.

  10. Radiation Chemical and Plasma Chemical Processes for Hydrogen Production from Water

    International Nuclear Information System (INIS)

    Hydrogen is considered to be the fuel of the future. The simplest way to produce hydrogen is by water decomposition. The usual, non-electrical method of producing this reaction is either by direct thermal water splitting or by making use of some catalytic process in a batch or flow reactor. The aim of the present work, which is part of the DEMO studies, is to investigate two further, little used methods for hydrogen production. I. Radiation Chemical Process Both fission and fusion reactors produce radioactive material, the radiation energy of which is wasted. By examining the water decomposition yields observed under different conditions we conclude that the radiolysis of high temperature water vapour in contact with oxide catalysts can produce sizable amounts of hydrogen. II. Plasma Chemical Process One of the most serious problems with thermal water decomposition lies with the high reaction temperature which, apart from other associated problems, demands highly corrosion resistant materials. Plasma chemical splitting removes this obstacle, but a mixture of O2 and H2 is formed and the separation of these products is quite difficult. Having investigated a number of high temperature processes where product separation might be easier, we conclude that the thermodynamic conditions of the reaction N2 + H2O = N2O + H2 appear attractive, additionally, N2O is easy to separate from H2. More detailed thermodynamic studies and relating kinetic investigations of this and analogous processes must follow in order to assess the practical use of plasma chemical methods. Energy carriers other than hydrogen, e.g. methane, methanol, formic acid, will also be considered, as these can also be synthesised in chemical plasmas by making use of fusion energy. The paper will report the results of the studies on both these processes for the production of hydrogen from fusion energy. (author)

  11. Simulation of a long term atmospheric corrosion process on plain and weathering steels

    Directory of Open Access Journals (Sweden)

    Bolivar, F.

    2003-12-01

    Full Text Available Information on weathering steel behaviour and its rust products characteristics after decades of atmospheric exposure are scarce. On the other side, generally accepted laboratory tests for the assessment of its corrosion resistance have not been developed yet. Consequently, simulating corrosion in the laboratory during long periods of time is attractive for the interesting and complete information obtainable from them. In the present work, AISI-SAE 1008 and ASTM-588 B steel samples have been exposed for two years to a immersion-emersion CEBELCOR type test in the laboratory, simulating a moderate urban atmosphere. Two groups of six samples each were tested. After the first year, three samples of each batch were retired for analysis and the rest was kept until they reached two years of exposure. The half cell electrode potentials were measured daily. The rust was characterized by metallographic techniques, Mossbauer spectroscopy (MS, Fourier transform infrared spectroscopy (FTIR, and X-ray diffraction (XRD. Comparison was done with field exposure experiments reported in the literature, and conclusions on the behaviour of tested samples were drawn looking for differences and similarities with samples and structures under actual atmospheric conditions.

    La información sobre el comportamiento y las características de los productos de corrosión de los aceros auto protectores, después de varias décadas de exposición a la atmósfera, es escasa. Por otra parte, aún no se han desarrollado ensayos de laboratorio de aceptación general para evaluar su resistencia a la corrosión. En consecuencia, cada día toman más importancia los ensayos de laboratorio durante largos periodos de exposición. En el presente trabajo, se sometieron muestras de acero AISI-SAE 1008 y ASTM 588-B, durante dos años, a un ensayo de laboratorio de inmersión-emersión tipo CEBELCOR. Se ensayaron dos grupos de seis muestras de cada composición de acero, en una

  12. A Framework to Design and Optimize Chemical Flooding Processes

    Energy Technology Data Exchange (ETDEWEB)

    Mojdeh Delshad; Gary A. Pope; Kamy Sepehrnoori

    2006-08-31

    The goal of this proposed research is to provide an efficient and user friendly simulation framework for screening and optimizing chemical/microbial enhanced oil recovery processes. The framework will include (1) a user friendly interface to identify the variables that have the most impact on oil recovery using the concept of experimental design and response surface maps, (2) UTCHEM reservoir simulator to perform the numerical simulations, and (3) an economic model that automatically imports the simulation production data to evaluate the profitability of a particular design. Such a reservoir simulation framework is not currently available to the oil industry. The objectives of Task 1 are to develop three primary modules representing reservoir, chemical, and well data. The modules will be interfaced with an already available experimental design model. The objective of the Task 2 is to incorporate UTCHEM reservoir simulator and the modules with the strategic variables and developing the response surface maps to identify the significant variables from each module. The objective of the Task 3 is to develop the economic model designed specifically for the chemical processes targeted in this proposal and interface the economic model with UTCHEM production output. Task 4 is on the validation of the framework and performing simulations of oil reservoirs to screen, design and optimize the chemical processes.

  13. Laser isotope separation - a new class of chemical process

    International Nuclear Information System (INIS)

    Lasers may soon find several applications in chemical processing. The applications that have attracted the most research funding to date involve isotope separation for the nuclear industry. These isotopes have an unusually high value (≥$1000/kg) compared to bulk chemicals (∼$1/kg) and are generally required in very large quantities. In a laser isotope separation process, light is used to convert a separation that is very difficult or even impossible by conventional chemical engineering techniques to one that is readily handled by conventional separation technology. For some isotopes this can result in substantial capital and energy savings. A uranium enrichment process developed at the Lawrence Livermore National Laboratory is the closest to commercialization of the large scale laser isotope separation processes. Of particular interest to the Canadian nuclear industry are the laser separation of deuterium, tritium, zirconium-90 and carbon-14. In this paper, the basic principles behind laser isotope separation are reviewed and brief dscriptions of the more developed processes are given

  14. Process/Equipment Co-Simulation on Syngas Chemical Looping Process

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Liang; Zhou, Qiang; Fan, Liang-Shih

    2012-09-30

    The chemical looping strategy for fossil energy applications promises to achieve an efficient energy conversion system for electricity, liquid fuels, hydrogen and/or chemicals generation, while economically separate CO{sub 2} by looping reaction design in the process. Chemical looping particle performance, looping reactor engineering, and process design and applications are the key drivers to the success of chemical looping process development. In order to better understand and further scale up the chemical looping process, issues such as cost, time, measurement, safety, and other uncertainties need to be examined. To address these uncertainties, advanced reaction/reactor modeling and process simulation are highly desired and the modeling efforts can accelerate the chemical looping technology development, reduce the pilot-scale facility design time and operating campaigns, as well as reduce the cost and technical risks. The purpose of this work is thus to conduct multiscale modeling and simulations on the key aspects of chemical looping technology, including particle reaction kinetics, reactor design and operation, and process synthesis and optimization.

  15. New trajectory driven aerosol and chemical process model: chemical and aerosol Lagrangian model (CALM)

    OpenAIRE

    Tunved, P.; D. G. Partridge; Korhonen, H.

    2010-01-01

    A new Chemical and Aerosol Lagrangian Model (CALM) have been developed and tested. The model incorporates all central aerosol dynamical processes, from nucleation, condensation, coagulation and deposition to cloud formation and in-cloud processing. The model is tested and evaluated against observations performed at the SMEAR II station located at Hyytiälä (61°51' N, 24°17' E) over a time period of two years, 2000–2001. The model shows good agreement with measurements thro...

  16. Diagnosing the Systematic Effects of Parametrized Physical Processes in a Numerical Weather Prediction Model

    Science.gov (United States)

    Saffin, Leo; Methven, John; Gray, Sue

    2016-04-01

    Numerical models of the atmosphere combine a dynamical core, which approximates solutions to the adiabatic and frictionless governing equations, with the tendencies arising from the parametrization of physical processes. Tracers of potential vorticity (PV) can be used to accumulate the tendencies of parametrized physical processes and diagnose their impacts on the large-scale dynamics. This is due to two key properties of PV, conservation following an air mass and invertibility which relates the PV distribution to the balanced dynamics of the atmosphere. Applying the PV tracers to many short forecasts allows for a systematic investigation of the behaviour of parametrized physical processes. The forecasts are 2.5 day lead time forecasts run using the Met Office Unified Model (MetUM) initialised at 0Z for each day in November/December/January 2013/14. The analysis of the PV tracers has been focussed on regions where diabatic processes can be important (tropopause ridges and troughs, frontal regions and the boundary layer top). The tropopause can be described as a surface of constant PV with a sharp PV gradient. Previous work using the PV tracers in individual case studies has shown that parametrized physical processes act to enhance the tropopause PV contrast which can affect the Rossby wave phase speed. The short forecasts show results consistent with a systematic enhancement of tropopause PV contrast by diabatic processes and show systematically different behaviour between ridges and troughs. The implication of this work is that a failure to correctly represent the effects of diabatic processes on the tropopause in models can lead to poor Rossby wave evolution and potentially downstream forecast busts.

  17. Cockpit weather information needs

    Science.gov (United States)

    Scanlon, Charles H.

    1992-01-01

    The primary objective is to develop an advanced pilot weather interface for the flight deck and to measure its utilization and effectiveness in pilot reroute decision processes, weather situation awareness, and weather monitoring. Identical graphical weather displays for the dispatcher, air traffic control (ATC), and pilot crew should also enhance the dialogue capabilities for reroute decisions. By utilizing a broadcast data link for surface observations, forecasts, radar summaries, lightning strikes, and weather alerts, onboard weather computing facilities construct graphical displays, historical weather displays, color textual displays, and other tools to assist the pilot crew. Since the weather data is continually being received and stored by the airborne system, the pilot crew has instantaneous access to the latest information. This information is color coded to distinguish degrees of category for surface observations, ceiling and visibilities, and ground radar summaries. Automatic weather monitoring and pilot crew alerting is accomplished by the airborne computing facilities. When a new weather information is received, the displays are instantaneously changed to reflect the new information. Also, when a new surface or special observation for the intended destination is received, the pilot crew is informed so that information can be studied at the pilot's discretion. The pilot crew is also immediately alerted when a severe weather notice, AIRMET or SIGMET, is received. The cockpit weather display shares a multicolor eight inch cathode ray tube and overlaid touch panel with a pilot crew data link interface. Touch sensitive buttons and areas are used for pilot selection of graphical and data link displays. Time critical ATC messages are presented in a small window that overlays other displays so that immediate pilot alerting and action can be taken. Predeparture and reroute clearances are displayed on the graphical weather system so pilot review of weather along

  18. Review of Life Cycle Assessment in Agro-Chemical Processes

    OpenAIRE

    Gillani, Sayed Tamizuddin; Belaud, Jean-Pierre; Sablayrolles, Caroline; Vignoles, Mireille; Le Lann, Jean-Marc

    2010-01-01

    Life Cycle Assessment (LCA) is a method used to evaluate the potential impacts on the environment of a product, process, or activity throughout its life cycle. Today’s LCA users are a mixture of individuals with skills in different disciplines who want to evaluate their products, processes, or activities in a life cycle context. This study attempts to present some of the LCA studies on agro-chemical processes, recent advances in LCA and their application on food products and non-food products...

  19. Transuranium element production. II. Chemical processing of targets

    International Nuclear Information System (INIS)

    The chemical processing described concerns small experimental targets irradiated in OSIRIS or EL-III and industrial targets irradiated in the CELESTIN reactors. In view of the difficulties encountered when processing highly irradiated targets (760MWd.kg-1) by liquid-liquid extraction (interface sludges leading to stable emulsion) the new processes developed are based on inverse phase chromatography. This technique applied to targets of americium 241, plutonium 239 and a plutonium mixture rich in isotope 242 has given tens of milligrams of curium 242, grams of americium 243 and curium 244 and micrograms of californium 252

  20. A chemical decontamination process for decontaminating and decommissioning nuclear reactors

    International Nuclear Information System (INIS)

    Five chemical decontamination processes have been developed for nuclear reactor applications. One of these processes is the cerium decontamination process (CDP). This method uses a cerium acid reagent to rapidly decontaminate surfaces, obtaining decontamination factors in excess of 300 in 6 h on pressurized water reactor specimens. Sound volume reduction and waste management techniques have been demonstrated, and solidified waste volume fractions as low as 9% experimentally obtained. The CDP method represents the hybrid decontamination technique often sought for component replacement and decommissioning operations: high effectiveness, rapid kinetics, simple waste treatment, and a low solidified waste volume

  1. Application of enzymes in leather processing: a comparison between chemical and coenzymatic processes

    Directory of Open Access Journals (Sweden)

    F. R. de Souza

    2012-09-01

    Full Text Available The use of biotechnology by tanneries has increased in recent years. Enzymes can be applied during different steps of the leather production process: soaking, dehairing, bating, dyeing, degreasing or in effluent and solid waste treatment. This study evaluated the performance of five commercial enzymes in soaking and unhairing/liming by comparing the chemical and coenzymatic processes. Tests were conducted in bench drums to evaluate the action of enzymes during each stage. Concentration, processing time and type of enzyme were varied. Total organic carbon and soluble protein were used to measure the efficiency of the processes. Enzymatic activity assays on collagen, keratin and lipid and scanning electron microscopic (SEM analyses of hides were used to complement the study. Coenzymatic processes generally showed better results in comparison to chemical processes. The enzymes showed activity on all substrates, and the SEM analyses of the hides showed a clear difference between the chemical and coenzymatic processes.

  2. Study on microwave assisted process in chemical extraction

    International Nuclear Information System (INIS)

    The microwave assisted process is a revolutionary method of extraction that reduces the extraction time to as little as a few seconds, with up to a ten-fold decrease in the use of solvents. The target material is immersed in solvent that is transparent to microwaves, so only the target material is heated, and because of the microwaves tend to heat the inside of the material quickly, the target chemical are expelled in a few seconds. benefits from this process include significant reductions in the amount of energy required and substantial reductions in the cost and dispose of hazardous solvents. A thorough review has been displayed on: using the microwave in extraction, applications of microwave in industry, process flow diagram, mechanism of the process and comparison between microwave process and other extraction techniques (soxhlet, steam distillation and supercritical fluid). This review attempts to summarize the studies about microwave assisted process as a very promising technique. (Author)

  3. Computer-Aided Multiscale Modelling for Chemical Process Engineering

    DEFF Research Database (Denmark)

    Morales Rodriguez, Ricardo; Gani, Rafiqul

    2007-01-01

    Chemical processes are generally modeled through monoscale approaches, which, while not adequate, satisfy a useful role in product-process design. In this case, use of a multi-dimensional and multi-scale model-based approach has importance in product-process development. A computer-aided framework...... for model generation, analysis, solution and implementation is necessary for the development and application of the desired model-based approach for product-centric process design/analysis. This goal is achieved through the combination of a system for model development (ModDev), and a modelling tool...... (MoT) for model translation, analysis and solution. The integration of ModDev, MoT and ICAS or any other external software or process simulator (using COM-Objects) permits the generation of different models and/or process configurations for purposes of simulation, design and analysis. Consequently, it...

  4. Chemical oxygen demand reduction in coffee wastewater through chemical flocculation and advanced oxidation processes

    Institute of Scientific and Technical Information of China (English)

    ZAYAS Pérez Teresa; GEISSLER Gunther; HERNANDEZ Fernando

    2007-01-01

    The removal of the natural organic matter present in coffee processing wastewater through chemical coagulation-flocculatio and advanced oxidation processes(AOP)had been studied.The effectiveness of the removal of natural organic matter using commercial flocculants and UV/H202,UVO3 and UV/H-H202/O3 processes was determined under acidic conditions.For each of these processes,different operational conditions were explored to optimize the treatment efficiency of the coffee wastewater.Coffee wastewater is characterized by a high chemical oxygen demand(COD)and low total suspended solids.The outcomes of coffee wastewater reeatment using coagulation-flocculation and photodegradation processes were assessed in terms of reduction of COD,color,and turbidity.It was found that a reductiOn in COD of 67%could be realized when the coffee wastewater was treated by chemical coagulation-flocculatlon witll lime and coagulant T-1.When coffee wastewater was treated by coagulation-flocculation in combination with UV/H202,a COD reduction of 86%was achieved,although only after prolonged UV irradiation.Of the three advanced oxidation processes considered,UV/H202,uv/03 and UV/H202/03,we found that the treatment with UV/H2O2/O3 was the most effective,with an efficiency of color,turbidity and further COD removal of 87%,when applied to the flocculated coffee wastewater.

  5. Chemical oxygen demand reduction in coffee wastewater through chemical flocculation and advanced oxidation processes.

    Science.gov (United States)

    Zayas Pérez, Teresa; Geissler, Gunther; Hernandez, Fernando

    2007-01-01

    The removal of the natural organic matter present in coffee processing wastewater through chemical coagulation-flocculation and advanced oxidation processes (AOP) had been studied. The effectiveness of the removal of natural organic matter using commercial flocculants and UV/H2O2, UV/O3 and UV/H2O2/O3 processes was determined under acidic conditions. For each of these processes, different operational conditions were explored to optimize the treatment efficiency of the coffee wastewater. Coffee wastewater is characterized by a high chemical oxygen demand (COD) and low total suspended solids. The outcomes of coffee wastewater treatment using coagulation-flocculation and photodegradation processes were assessed in terms of reduction of COD, color, and turbidity. It was found that a reduction in COD of 67% could be realized when the coffee wastewater was treated by chemical coagulation-flocculation with lime and coagulant T-1. When coffee wastewater was treated by coagulation-flocculation in combination with UV/H2O2, a COD reduction of 86% was achieved, although only after prolonged UV irradiation. Of the three advanced oxidation processes considered, UV/H2O2, UV/O3 and UV/H2O2/O3, we found that the treatment with UV/H2O2/O3 was the most effective, with an efficiency of color, turbidity and further COD removal of 87%, when applied to the flocculated coffee wastewater. PMID:17918591

  6. ROBUST TEMPERATURE CONTROLLER DESIGN FOR A CHEMICAL PROCESS

    Directory of Open Access Journals (Sweden)

    G.Glan Devadhas

    2010-10-01

    Full Text Available This paper attempts to tuning out a new PID control strategy to provide Robust Control for a Chemical process. Chemical process control is a challenging problem due to the strong on-line non-linearity and extreme sensitivity to disturbances of the process. The proposed method has the advantage that it takes into account all the parameters variations associated with the process. The variations in the process parameters are modeled as a gaussian noise and an adaptive gaussian filter is placed in the feedback path. The adaptivegaussian filter in the feedback path adapts its filter coefficients based on a kalman estimation algorithm. This adaptive filter adapts so as to maintain the mean square error a minimum. The LQG (Linear Quadratic Gaussian in Robust Control is used in designing of the proposed strategy. The analysis of a PID tuning [7] strategy and the necessity of such an adaptive strategy is also explored in this paper. The proposed strategy of Robust Control has been designed for a First Order Lag Plus Delay (FOLPD process. The proposed strategy ofRobust Control has been simulated for an FOLPD process in SIMULINK.

  7. Biogeochemical weathering under ice: Size matters

    Science.gov (United States)

    Wadham, J. L.; Tranter, M.; Skidmore, M.; Hodson, A. J.; Priscu, J.; Lyons, W. B.; Sharp, M.; Wynn, P.; Jackson, M.

    2010-09-01

    The basal regions of continental ice sheets are gaps in our current understanding of the Earth's biosphere and biogeochemical cycles. We draw on existing and new chemical data sets for subglacial meltwaters to provide the first comprehensive assessment of sub-ice sheet biogeochemical weathering. We show that size of the ice mass is a critical control on the balance of chemical weathering processes and that microbial activity is ubiquitous in driving dissolution. Carbonate dissolution fueled by sulfide oxidation and microbial CO2 dominate beneath small valley glaciers. Prolonged meltwater residence times and greater isolation characteristic of ice sheets lead to the development of anoxia and enhanced silicate dissolution due to calcite saturation. We show that sub-ice sheet environments are highly geochemically reactive and should be considered in regional and global solute budgets. For example, calculated solute fluxes from Antarctica (72-130 t yr-1) are the same order of magnitude as those from some of the world's largest rivers and rates of chemical weathering (10-17 t km-2 yr-1) are high for the annual specific discharge (2.3-4.1 × 10-3 m). Our model of chemical weathering dynamics provides important information on subglacial biodiversity and global biogeochemical cycles and may be used to design strategies for the first sampling of Antarctic Subglacial Lakes and other sub-ice sheet environments for the next decade.

  8. Frost weathering versus glacial grinding in the micromorphology of quartz sand grains: Processes and geological implications

    Science.gov (United States)

    Woronko, Barbara

    2016-04-01

    Micromorphology of quartz sand grains is used to reconstruct processes occurring in the glacial environment and to distinguish the latter from other environments. Two processes dominate in the glacial environment, i.e., crushing and abrasion, or a combination thereof. Their effect is a wide range of microstructures on the surface of quartz grains, e.g., chattermarks, conchoidal fractures and multiple grooves. However, the periglacial environment also effectively modifies the surface of quartz grains. The active layer of permafrost is considered to have a significantly higher contribution to the formation of crushed grains and the number of microstructures resulting from mechanical destruction (e.g., breakage blocks or conchoidal fractures), as compared to deposits which are not affected by freeze-thaw cycles. However, only a few microstructures are found in both environments. At the same time, there are several processes in subglacial environments related to freeze-thaw cycles, e.g., regelation, congelation, basal adfreezing, and glaciohydraulic supercooling. Most likely, therefore, the role of the glacial environment in the destruction of quartz grains has been misinterpreted, and consequently the conclusions regarding environmental processes drawn on the basis of the number of crushed grains and edge-to-edge contacts are erroneous.

  9. Impact of bacterial and fungal processes on 14C-hexadecane mineralisation in weathered hydrocarbon contaminated soil

    International Nuclear Information System (INIS)

    In this study, the impact of bacterial and fungal processes on 14C-hexadecane mineralisation was investigated in weathered hydrocarbon contaminated soil. The extent of 14C-hexadecane mineralisation varied depending on the bioremediation strategy employed. Under enhanced natural attenuation conditions, 14C-hexadecane mineralisation after 98 days was 8.5 ± 3.7% compared to 14C-hexadecane mineralisation was further enhanced through Tween 80 amendments (28.9 ± 2.4%) which also promoted the growth of a Phanerochaete chyrsosporium fungal mat. Although fungal growth in weathered hydrocarbon contaminated soil could be promoted through supplementing additional carbon sources (Tween 80, sawdust, compost, pea straw), fungal 14C-hexadecane mineralisation was negligible when sodium azide was added to soil microcosms to inhibit bacterial activity. In contrast, when fungal activity was inhibited through nystatin additions, 14C-hexadecane mineralisation ranged from 6.5 ± 0.2 to 35.8 ± 3.8% after 98 days depending on the supplied amendment. Bacteria inhibition with sodium azide resulted in a reduction in bacterial diversity (33–37%) compared to microcosms supplemented with nystatin or microcosms without inhibitory supplements. However, alkB bacterial groups were undetected in sodium azide supplemented microcosms, highlighting the important role of this bacterial group in 14C-hexadecane mineralisation. - Highlights: ► The roles of different microbial groups in hydrocarbon mineralisation was assessed. ► Inhibiting fungal growth did not affect 14C-hexadecane mineralisation. ► Inhibiting bacterial growth resulted in negligible 14C-hexadecane mineralisation. ► alkB bacterial groups were undetected in sodium azide supplemented microcosms. ► The importance of alkB groups in 14C-hexadecane mineralisation was highlighted.

  10. Enhancing Cloud Radiative Processes and Radiation Efficiency in the Advanced Research Weather Research and Forecasting (WRF) Model

    Energy Technology Data Exchange (ETDEWEB)

    Iacono, Michael J. [Atmospheric and Environmental Research, Lexington, MA (United States)

    2015-03-09

    The objective of this research has been to evaluate and implement enhancements to the computational performance of the RRTMG radiative transfer option in the Advanced Research version of the Weather Research and Forecasting (WRF) model. Efficiency is as essential as accuracy for effective numerical weather prediction, and radiative transfer is a relatively time-consuming component of dynamical models, taking up to 30-50 percent of the total model simulation time. To address this concern, this research has implemented and tested a version of RRTMG that utilizes graphics processing unit (GPU) technology (hereinafter RRTMGPU) to greatly improve its computational performance; thereby permitting either more frequent simulation of radiative effects or other model enhancements. During the early stages of this project the development of RRTMGPU was completed at AER under separate NASA funding to accelerate the code for use in the Goddard Space Flight Center (GSFC) Goddard Earth Observing System GEOS-5 global model. It should be noted that this final report describes results related to the funded portion of the originally proposed work concerning the acceleration of RRTMG with GPUs in WRF. As a k-distribution model, RRTMG is especially well suited to this modification due to its relatively large internal pseudo-spectral (g-point) dimension that, when combined with the horizontal grid vector in the dynamical model, can take great advantage of the GPU capability. Thorough testing under several model configurations has been performed to ensure that RRTMGPU improves WRF model run time while having no significant impact on calculated radiative fluxes and heating rates or on dynamical model fields relative to the RRTMG radiation. The RRTMGPU codes have been provided to NCAR for possible application to the next public release of the WRF forecast model.

  11. DOE Workshop; Pan-Gass Conference on the Representation of Atmospheric Processes in Weather and Climate Models

    Energy Technology Data Exchange (ETDEWEB)

    Morrison, PI Hugh

    2012-09-21

    This is the first meeting of the whole new GEWEX (Global Energy and Water Cycle Experiment) Atmospheric System Study (GASS) project that has been formed from the merger of the GEWEX Cloud System Study (GCSS) Project and the GEWEX Atmospheric Boundary Layer Studies (GABLS). As such, this meeting will play a major role in energizing GEWEX work in the area of atmospheric parameterizations of clouds, convection, stable boundary layers, and aerosol-cloud interactions for the numerical models used for weather and climate projections at both global and regional scales. The representation of these processes in models is crucial to GEWEX goals of improved prediction of the energy and water cycles at both weather and climate timescales. This proposal seeks funds to be used to cover incidental and travel expenses for U.S.-based graduate students and early career scientists (i.e., within 5 years of receiving their highest degree). We anticipate using DOE funding to support 5-10 people. We will advertise the availability of these funds by providing a box to check for interested participants on the online workshop registration form. We will also send a note to our participants' mailing lists reminding them that the funds are available and asking senior scientists to encourage their more junior colleagues to participate. All meeting participants are encouraged to submit abstracts for oral or poster presentations. The science organizing committee (see below) will base funding decisions on the relevance and quality of these abstracts, with preference given to under-represented populations (especially women and minorities) and to early career scientists being actively mentored at the meeting (e.g. students or postdocs attending the meeting with their advisor).

  12. Microbiology and atmospheric processes: chemical interactions of primary biological aerosols

    Directory of Open Access Journals (Sweden)

    L. Deguillaume

    2008-07-01

    Full Text Available This paper discusses the influence of primary biological aerosols (PBA on atmospheric chemistry and vice versa through microbiological and chemical properties and processes. Several studies have shown that PBA represent a significant fraction of air particulate matter and hence affect the microstructure and water uptake of aerosol particles. Moreover, airborne micro-organisms, namely fungal spores and bacteria, can transform chemical constituents of the atmosphere by metabolic activity. Recent studies have emphasized the viability of bacteria and metabolic degradation of organic substances in cloud water. On the other hand, the viability and metabolic activity of airborne micro-organisms depend strongly on physical and chemical atmospheric parameters such as temperature, pressure, radiation, pH value and nutrient concentrations. In spite of recent advances, however, our knowledge of the microbiological and chemical interactions of PBA in the atmosphere is rather limited. Further targeted investigations combining laboratory experiments, field measurements, and modelling studies will be required to characterize the chemical feedbacks, microbiological activities at the air/snow/water interface supplied to the atmosphere.

  13. New Vistas in Chemical Product and Process Design.

    Science.gov (United States)

    Zhang, Lei; Babi, Deenesh K; Gani, Rafiqul

    2016-06-01

    Design of chemicals-based products is broadly classified into those that are process centered and those that are product centered. In this article, the designs of both classes of products are reviewed from a process systems point of view; developments related to the design of the chemical product, its corresponding process, and its integration are highlighted. Although significant advances have been made in the development of systematic model-based techniques for process design (also for optimization, operation, and control), much work is needed to reach the same level for product design. Timeline diagrams illustrating key contributions in product design, process design, and integrated product-process design are presented. The search for novel, innovative, and sustainable solutions must be matched by consideration of issues related to the multidisciplinary nature of problems, the lack of data needed for model development, solution strategies that incorporate multiscale options, and reliability versus predictive power. The need for an integrated model-experiment-based design approach is discussed together with benefits of employing a systematic computer-aided framework with built-in design templates. PMID:27088667

  14. Process Control Systems in the Chemical Industry: Safety vs. Security

    Energy Technology Data Exchange (ETDEWEB)

    Jeffrey Hahn; Thomas Anderson

    2005-04-01

    Traditionally, the primary focus of the chemical industry has been safety and productivity. However, recent threats to our nation’s critical infrastructure have prompted a tightening of security measures across many different industry sectors. Reducing vulnerabilities of control systems against physical and cyber attack is necessary to ensure the safety, security and effective functioning of these systems. The U.S. Department of Homeland Security has developed a strategy to secure these vulnerabilities. Crucial to this strategy is the Control Systems Security and Test Center (CSSTC) established to test and analyze control systems equipment. In addition, the CSSTC promotes a proactive, collaborative approach to increase industry's awareness of standards, products and processes that can enhance the security of control systems. This paper outlines measures that can be taken to enhance the cybersecurity of process control systems in the chemical sector.

  15. Eruptive Process, Geochemical Variation, and Weathering Controls on the Hyperspectral Reflectance Properties of the Blue Dragon Lava Flow, Craters of the Moon National Monument

    Science.gov (United States)

    Poplawski, J.; Chadwick, D. J.

    2010-12-01

    About 60 eruptive events have occurred at the Craters of the Moon volcanic field (Idaho, US), ranging in age from 15 to 2 ka. The Blue Dragon flow is one of the youngest, a large (280 sq. km) hawaiite flow which erupted from a dike-fed central rift zone, the Great Rift. Airborne Visible Infrared Imaging Spectrometer (AVIRIS) hyperspectral imagery (224-bands, 0.4 to 2.5 micron spectral range, and 15.3 m spatial resolution) shows at least five distinct regions within the Blue Dragon flow that exhibit different spectral reflectance properties. Field observations show these regions to be associated with different eruptive phases of the flow, and in some cases, different flow morphologies (e.g. aa, and ropey, sheet, and hummocky pahoehoe). Airborne Synthetic Aperture Radar (AIRSAR) imagery of the study area also shows average roughness variability among the different spectral regions. We performed petrographic and laboratory spectral analyses on samples from each spectral region to investigate variation in primary surface properties and the effects of weathering and lichen growth on surface reflectance. We also analyzed bulk major elements for several samples from each spectral region to investigate a possible connection between the observed spectral variability and chemical variability in the Blue Dragon eruption over time. Analyses using hydrologic flow accumulation and solar irradiance models provide further information about the effects of post-eruptive processes on spectral reflectance of the flow.

  16. Wacky Weather

    Science.gov (United States)

    Sabarre, Amy; Gulino, Jacqueline

    2013-01-01

    What do a leaf blower, water hose, fan, and ice cubes have in common? Ask the students who participated in an integrative science, technology, engineering, and mathematics (I-STEM) education unit, "Wacky Weather," and they will tell say "fun and severe weather"--words one might not have expected! The purpose of the unit…

  17. AN overview of the FLYSAFE datalink solution for the exchange of weather information: supporting aircrew decision making processes.

    Science.gov (United States)

    Mirza, A.; Drouin, A.

    2009-09-01

    FLYSAFE is an Integrated Project of the 6th framework of the European Commission with the aim to improve flight safety through the development of an avionics solution the Next Generation Integrated Surveillance System (NGISS), which is supported by a ground based network of Weather Information Management Systems (WIMS) and access points in the form of the Ground Weather Processor (GWP). The NGISS provides information to the flight crew on the three major external hazards for aviation: weather, air traffic and terrain. The NGISS has the capability of displaying data about all three hazards on a single display screen, facilitating rapid appreciation of the situation by the flight crew. Weather Information Management Systems (WIMS) were developed to provide the NGISS and the flight crew with weather related information on in-flight icing, thunderstorms and clear-air turbulence. These products are generated on the ground from observations and model forecasts. WIMS will supply relevant information on three different scales: global, regional and local (over airport Terminal Manoeuvring Area). The Ground Weather Processor is a client-server architecture that utilises open source components, which include a geospatial database and web feature services. The GWP stores Weather Objects generated by the WIMS. An aviation user can retrieve on-demand all Weather Objects that intersect the volume of space that is of interest to them. The Weather Objects are fused with in-situ observation data and can be used by the flight management system to propose a route to avoid the hazard. In addition they can be used to display the current hazardous weather to the Flight Crew thereby raising their awareness. Within the FLYSAFE program, around 120 hours of flight trials were performed during February 2008 and August 2008. Two aircraft were involved each with separate objectives: - to assess FLYSAFE's innovative solutions for the data-link, on-board data-fusion and data-display and data

  18. Silicon isotope systematics of acidic weathering of fresh basalts, Kilauea Volcano, Hawai’i

    OpenAIRE

    Chemtob, Steven M.; Rossman, George R.; Young, Edward D.; Ziegler, Karen; Moynier, Fréderic; Eiler, John M.; Hurowitz, Joel A.

    2015-01-01

    Silicon stable isotopes are fractionated by a host of low-temperature aqueous processes, making them potentially useful as a weathering proxy. Here we characterize the silicon isotope signature of surficial chemical weathering of glassy basaltic lava flows at Kilauea Volcano, Hawaii. Fresh basalt flow surfaces (

  19. Conventional and chemical processing of high Tc superconductors

    International Nuclear Information System (INIS)

    Conventional and chemical processing of the superconducting YBa2Cu3Ox ceramic powders are reviewed. Conditions for calcination, sintering and microstructural development are shown to be important considerations for the superconducting properties of YBa2Cu3Ox ceramics. The authors examine different forming techniques, e.g. dry pressing, hot pressing, tape casting and screen printing, to prepare superconducting components with different sizes, shapes and configurations

  20. Quality costs and robustness criteria in chemical process design optimization

    OpenAIRE

    Bernardo, Fernando P.; Pistikopoulos, Efstratios N; Pedro M. Saraiva

    2001-01-01

    The identification and incorporation of quality costs and robustness criteria is becoming a critical issue while addressing chemical process design problems under uncertainty. This article presents a systematic design framework that includes Taguchi loss functions and other robustness criteria within a single-level stochastic optimization formulation, with expected values in the presence of uncertainty being estimated by an efficient cubature technique. The solution obtained defines an optima...

  1. Vibration and Stability of 3000-hp, Titanium Chemical Process Blower

    Directory of Open Access Journals (Sweden)

    Les Gutzwiller

    2003-01-01

    Full Text Available This 74-in-diameter blower had an overhung rotor design of titanium construction, operating at 50 pounds per square inch gauge in a critical chemical plant process. The shaft was supported by oil-film bearings and was directdriven by a 3000-hp electric motor through a metal disk type of coupling. The operating speed was 1780 rpm. The blower shaft and motor shaft motion was monitored by Bently Nevada proximity probes and a Model 3100 monitoring system.

  2. Technical evaluation on some chemical exchange process for uranium enrichment

    International Nuclear Information System (INIS)

    In CEA in France, Asahi Chemical Industry Co., Ltd., in Japan and others, the industrialization of the uranium enrichment by chemical processes has been studied independently for ten years, using large amount of research expenses. In this study, technological examination was carried out on such processes and their separation characteristics, based on the published literatures. As the results, it was recognized that they have sufficient separation capability to aim at the industrialization, and the power required can be limited relatively low. However, very precise plant design and operation control system are required for them, and it is necessary to watch the future course to carry out the objective evaluation of the economic efficiency. The electric power has become a dominant factor in the production cost of enriched uranium. The separation of uranium isotopes with anion exchange resin being developed by Asahi Chemical Industry Co., Ltd., and the isotope separation by electron exchange using solvent extraction method being developed by CEA in France are introduced. Though the equilibrium separation factor is very small, they utilize reversible processes, and have the possibility of large power reduction and the cost reduction due to scaling-up. (Kako, I.)

  3. Numerical simulation of chemical processes in atmospheric plasmas

    Institute of Scientific and Technical Information of China (English)

    Ouyang Jian-Ming; Guo Wei; Wang Long; Shao Fu-Qiu

    2004-01-01

    A model is built to study chemical processes in atmospheric plasmas at low altitude (high pressure) and at high altitude (low pressure). The plasma lifetime and the temporal evolution of the main charged species are presented.The electron number density does not strictly obey the exponential damping law in a long period. The heavy charged species are dominant at low altitude in comparison with the light species at high altitude. Some species of small amount in natural air play an important role in the processes.

  4. Chemical Assessment of White Wine during Fermentation Process

    Directory of Open Access Journals (Sweden)

    Teodora Coldea

    2014-05-01

    Full Text Available There were investigated chemical properties of indigenous white wine varieties (Fetească albă, Fetească regală and Galbenă de Odobeşti during fermentation. The white wine making process took place at Wine Pilot Station of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca. We aimed to monitorize the evolution of fermentation process parameters (temperature, alcohol content, and real extract and the quality of the bottled white wine (total acidity, alcohol content, total sulfur dioxide, total dry extract. The results obtained were in accordance to Romanian Legislation.

  5. Supercritical Water Process for the Chemical Recycling of Waste Plastics

    Science.gov (United States)

    Goto, Motonobu

    2010-11-01

    The development of chemical recycling of waste plastics by decomposition reactions in sub- and supercritical water is reviewed. Decomposition reactions proceed rapidly and selectively using supercritical fluids compared to conventional processes. Condensation polymerization plastics such as PET, nylon, and polyurethane, are relatively easily depolymerized to their monomers in supercritical water. The monomer components are recovered in high yield. Addition polymerization plastics such as phenol resin, epoxy resin, and polyethylene, are also decomposed to monomer components with or without catalysts. Recycling process of fiber reinforced plastics has been studied. Pilot scale or commercial scale plants have been developed and are operating with sub- and supercritical fluids.

  6. The use of imprecise processing to improve accuracy in weather and climate prediction

    International Nuclear Information System (INIS)

    The use of stochastic processing hardware and low precision arithmetic in atmospheric models is investigated. Stochastic processors allow hardware-induced faults in calculations, sacrificing bit-reproducibility and precision in exchange for improvements in performance and potentially accuracy of forecasts, due to a reduction in power consumption that could allow higher resolution. A similar trade-off is achieved using low precision arithmetic, with improvements in computation and communication speed and savings in storage and memory requirements. As high-performance computing becomes more massively parallel and power intensive, these two approaches may be important stepping stones in the pursuit of global cloud-resolving atmospheric modelling. The impact of both hardware induced faults and low precision arithmetic is tested using the Lorenz '96 model and the dynamical core of a global atmosphere model. In the Lorenz '96 model there is a natural scale separation; the spectral discretisation used in the dynamical core also allows large and small scale dynamics to be treated separately within the code. Such scale separation allows the impact of lower-accuracy arithmetic to be restricted to components close to the truncation scales and hence close to the necessarily inexact parametrised representations of unresolved processes. By contrast, the larger scales are calculated using high precision deterministic arithmetic. Hardware faults from stochastic processors are emulated using a bit-flip model with different fault rates. Our simulations show that both approaches to inexact calculations do not substantially affect the large scale behaviour, provided they are restricted to act only on smaller scales. By contrast, results from the Lorenz '96 simulations are superior when small scales are calculated on an emulated stochastic processor than when those small scales are parametrised. This suggests that inexact calculations at the small scale could reduce computation and

  7. ACTINIDE REMOVAL PROCESS SAMPLE ANALYSIS, CHEMICAL MODELING, AND FILTRATION EVALUATION

    Energy Technology Data Exchange (ETDEWEB)

    Martino, C.; Herman, D.; Pike, J.; Peters, T.

    2014-06-05

    Filtration within the Actinide Removal Process (ARP) currently limits the throughput in interim salt processing at the Savannah River Site. In this process, batches of salt solution with Monosodium Titanate (MST) sorbent are concentrated by crossflow filtration. The filtrate is subsequently processed to remove cesium in the Modular Caustic Side Solvent Extraction Unit (MCU) followed by disposal in saltstone grout. The concentrated MST slurry is washed and sent to the Defense Waste Processing Facility (DWPF) for vitrification. During recent ARP processing, there has been a degradation of filter performance manifested as the inability to maintain high filtrate flux throughout a multi-batch cycle. The objectives of this effort were to characterize the feed streams, to determine if solids (in addition to MST) are precipitating and causing the degraded performance of the filters, and to assess the particle size and rheological data to address potential filtration impacts. Equilibrium modelling with OLI Analyzer{sup TM} and OLI ESP{sup TM} was performed to determine chemical components at risk of precipitation and to simulate the ARP process. The performance of ARP filtration was evaluated to review potential causes of the observed filter behavior. Task activities for this study included extensive physical and chemical analysis of samples from the Late Wash Pump Tank (LWPT) and the Late Wash Hold Tank (LWHT) within ARP as well as samples of the tank farm feed from Tank 49H. The samples from the LWPT and LWHT were obtained from several stages of processing of Salt Batch 6D, Cycle 6, Batch 16.

  8. Application of repetitive pulsed power technology to chemical processing

    International Nuclear Information System (INIS)

    The numerous sites of soil and water contaminated with organic chemicals present an urgent environmental concern that continues to grow. Electron and x-ray irradiation have been shown to be effective methods to destroy a wide spectrum of organic chemicals, nitrates, nitrites, and cyanide in water by breaking molecules to non-toxic products or entirely mineralizing the by-products to gas, water, and salts. Sandia National Laboratories is developing Repetitive High Energy Pulsed Power (RHEPP) technology capable of producing high average power, broad area electron or x-ray beams. The 300 kW RHEPP-II facility accelerates electrons to 2.5 MeV at 25 kA over 1,000 cm2 in 60 ns pulses at repetition rates of over 100 Hz. Linking this modular treatment capability with the rapid optical-sensing diagnostics and neutral network characterization software algorithms will provide a Smart Waste Treatment (SWaT) system. Such a system would also be applicable for chemical manufacture and processing of industrial waste for reuse or disposal. This talk describes both the HREPP treatment capability and sensing technologies. Measurements of the propagated RHEPP-II beam and dose profiles are presented. Sensors and rapid detection software are discussed with application toward chemical treatment

  9. Influence of surface coverage on the chemical desorption process

    CERN Document Server

    Marco, Minissale

    2014-01-01

    In cold astrophysical environments, some molecules are observed in the gas phase whereas they should have been depleted, frozen on dust grains. In order to solve this problem, astrochemists have proposed that a fraction of molecules synthesized on the surface of dust grains could desorb just after their formation. Recently the chemical desorption process has been demonstrated experimentally, but the key parameters at play have not yet been fully understood. In this article we propose a new procedure to analyze the ratio of di-oxygen and ozone synthesized after O atoms adsorption on oxidized graphite. We demonstrate that the chemical desorption efficiency of the two reaction paths (O+O and O+O$_2$) is different by one order of magnitude. We show the importance of the surface coverage: for the O+O reaction, the chemical desorption efficiency is close to 80 $\\%$ at zero coverage and tends to zero at one monolayer coverage. The coverage dependence of O+O chemical desorption is proved by varying the amount of pre-...

  10. New trajectory-driven aerosol and chemical process model Chemical and Aerosol Lagrangian Model (CALM)

    OpenAIRE

    Tunved, P.; D. G. Partridge; Korhonen, H.

    2010-01-01

    A new Chemical and Aerosol Lagrangian Model (CALM) has been developed and tested. The model incorporates all central aerosol dynamical processes, from nucleation, condensation, coagulation and deposition to cloud formation and in-cloud processing. The model is tested and evaluated against observations performed at the SMEAR II station located at Hyytiälä (61° 51' N, 24° 17' E) over a time period of two years, 2000–2001. The model shows good agreement with measurements throughout mos...

  11. Incorporation of chemical kinetic models into process control

    International Nuclear Information System (INIS)

    An important consideration in chemical process control is to determine the precise rationing of reactant streams, particularly when a large time delay exists between the mixing of the reactants and the measurement of the product. In this paper, a method is described for incorporating chemical kinetic models into the control strategy in order to achieve optimum operating conditions. The system is first characterized by determining a reaction rate surface as a function of all input reactant concentrations over a feasible range. A nonlinear constrained optimization program is then used to determine the combination of reactants which produces the specified yield at minimum cost. This operating condition is then used to establish the nominal concentrations of the reactants. The actual operation is determined through a feedback control system employing a Smith predictor. The method is demonstrated on a laboratory bench scale enzyme reactor

  12. Chemical evolution of the Earth: Equilibrium or disequilibrium process?

    Science.gov (United States)

    Sato, M.

    1985-01-01

    To explain the apparent chemical incompatibility of the Earth's core and mantle or the disequilibrium process, various core forming mechanisms have been proposed, i.e., rapid disequilibrium sinking of molten iron, an oxidized core or protocore materials, and meteorite contamination of the upper mantle after separation from the core. Adopting concepts used in steady state thermodynamics, a method is devised for evaluating how elements should distribute stable in the Earth's interior for the present gradients of temperature, pressure, and gravitational acceleration. Thermochemical modeling gives useful insights into the nature of chemical evolution of the Earth without overly speculative assumptions. Further work must be done to reconcile siderophile elements, rare gases, and possible light elements in the outer core.

  13. Mechanistic, kinetic, and processing aspects of tungsten chemical mechanical polishing

    Science.gov (United States)

    Stein, David

    This dissertation presents an investigation into tungsten chemical mechanical polishing (CMP). CMP is the industrially predominant unit operation that removes excess tungsten after non-selective chemical vapor deposition (CVD) during sub-micron integrated circuit (IC) manufacture. This work explores the CMP process from process engineering and fundamental mechanistic perspectives. The process engineering study optimized an existing CMP process to address issues of polish pad and wafer carrier life. Polish rates, post-CMP metrology of patterned wafers, electrical test data, and synergy with a thermal endpoint technique were used to determine the optimal process. The oxidation rate of tungsten during CMP is significantly lower than the removal rate under identical conditions. Tungsten polished without inhibition during cathodic potentiostatic control. Hertzian indenter model calculations preclude colloids of the size used in tungsten CMP slurries from indenting the tungsten surface. AFM surface topography maps and TEM images of post-CMP tungsten do not show evidence of plow marks or intergranular fracture. Polish rate is dependent on potassium iodate concentration; process temperature is not. The colloid species significantly affects the polish rate and process temperature. Process temperature is not a predictor of polish rate. A process energy balance indicates that the process temperature is predominantly due to shaft work, and that any heat of reaction evolved during the CMP process is negligible. Friction and adhesion between alumina and tungsten were studied using modified AFM techniques. Friction was constant with potassium iodate concentration, but varied with applied pressure. This corroborates the results from the energy balance. Adhesion between the alumina and the tungsten was proportional to the potassium iodate concentration. A heuristic mechanism, which captures the relationship between polish rate, pressure, velocity, and slurry chemistry, is presented

  14. A chemical cleaning process with Cerium (IV)-sulfuric acid

    International Nuclear Information System (INIS)

    A chemical cleaning process with a high decontamination factor (DF) is requested for decommissioning. Usually, the process should be qualified with the features, such as the feasibility of treating large or complicated form waste, the minimization of secondary waste. Therefore, a powerful technique of redox decontamination process with Ce+4/Ce+3 has been studied at INER. First, the redox of cerium ion with electrolytic method was developed. Two kinds of home-made electrolyzer were used. One is with an ion-exchange membrane, and the other one is with a ceramic separator. Second, factors influencing the decontamination efficiency, such as the concentration of Ce+4, regeneration current density, temperature, acidity of solution were all studied experimentally, and the optimum conditions were specified too. Third, the liquid waste recycling and treatment were developed with electrodialysis and ion-exchange absorption methods. Finally, the hot test was proceeded with the contaminated metals from DCR of nuclear facility. (author)

  15. Mirador - Weather

    Data.gov (United States)

    National Aeronautics and Space Administration — Earth Science data access made simple. Our weather system includes the dynamics of the atmosphere and its interaction with the oceans and land. The improvement of...

  16. Inhomogeneity of photodegradation processes in bulk comodity polymers subjected to accelerated weathering studied by ESRI and other physical methods

    Czech Academy of Sciences Publication Activity Database

    Pilař, Jan; Pfleger, Jiří; Trchová, Miroslava; Michálková, Danuše; Pospíšil, Jan

    Pfinztal: Confederation of European Environmental Engineering Societies (CEEES)- Gesellschaft für Umweltsimulation GUS, 2009 - (Reichert, T.), s. 83-95 ISBN 978-3-9810472-8-8. [European Weathering Symposium /4./. Budapest (HU), 16.09.2009-18.09.2009] R&D Projects: GA AV ČR IAA400500804 Institutional research plan: CEZ:AV0Z40500505 Keywords : polymer degradation * hindered amine stabilizers * accelerated weathering Subject RIV: CD - Macromolecular Chemistry

  17. Rate controls on the chemical weathering of natural polymineralic material. I. Dissolution behaviour of polymineralic assemblages determined using batch and unsaturated column experiments

    International Nuclear Information System (INIS)

    Chemical weathering rates for a mudstone obtained from a mining environment were investigated using a combination of batch reactors and hydrologically unsaturated column experiments. Results of tracer tests were combined with relationships between solute concentrations, mass fluxes, flow rates and residence times, and used to calculate element release rates and infer rate-controlling mechanisms for the two different experimental environments. Elements that eluted from column experiments exhibited either:(1)concentrations independent of flow rate and column length coupled with mass flux increasing with flow rate, or (2)an inverse relationship between concentration and flow rate coupled with mass flux increasing with both column length and flow rate. The former is attributed to equilibrium-controlled release of particular elements (Si, Al), while the latter is ascribed to transport-controlled release of others (Mg, Mn, Ca, Na, K, S). Tracer tests using NaBr solutions revealed that some elements were also affected by ion exchange (Mg, Mn, Ca, Na), but these effects were temporary and did not mask underlying dissolution rate-controlling mechanisms. Analysis of characteristic diffusive lengths was used to distinguish between transport rates limited by the transfer of solutes between immobile and mobile water within the columns, and rates limited by slow diffusion across partially reacted mineral layers. The analysis suggests that transfer between immobile and mobile water limited the element release rates, with diffusion hindered by low diffusion coefficients within the unsaturated medium, and by low interfacial areas between mobile and immobile fluids. Results of the batch experiments showed different characteristics. Element concentrations either rose to a plateau or increased linearly with time. Rate-controlling mechanisms associated with these characteristics were equilibrium (Fe) and surface kinetic reactions (Si, Mg, Mn, Ca, K, S), respectively. Surface area

  18. 'Exalting Understanding without Depressing Imagination': Depicting Chemical Process

    Directory of Open Access Journals (Sweden)

    David Knight

    2003-10-01

    Full Text Available Alchemists' illustrations indicated through symbols the processes being attempted; but with Lavoisier's Elements (1789, the place of imagination and symbolic language in chemistry was much reduced. He sought to make chemistry akin to algebra and its illustrations merely careful depictions of apparatus. Although younger contemporaries sought, and found in electrochemistry, a dynamical approach based upon forces rather than weights, they found this very difficult to picture. Nevertheless, by looking at chemical illustrations in the eighty years after Lavoisier's revolutionary book, we can learn about how reactions were carried out, and interpreted, and see that there was scope for aesthetic judgement and imagination.

  19. Fundamental studies of chemical vapor deposition diamond growth processes

    International Nuclear Information System (INIS)

    We are developing laser spectroscopic techniques to foster a fundamental understanding of diamond film growth by hot filament chemical vapor deposition (CVD). Several spectroscopic techniques are under investigation to identify intermediate species present in the bulk reactor volume, the thin active volume immediately above the growing film, and the actual growing surface. Such a comprehensive examination of the overall deposition process is necessary because a combination of gas phase and surface chemistry is probably operating. Resonantly enhanced multiphoton ionization (REMPI) techniques have been emphasized. A growth rector that permits through-the-substrate gas sampling for REMPI/time-of-flight mass spectroscopy has been developed. 7 refs., 2 figs

  20. Optimization of radiation-chemical process of trichloroethylene oxidation

    International Nuclear Information System (INIS)

    Kinetics of trichloroethylene (TCE) oxidation under the effect of gamma-irradiation is investigated. It is shown that the reaction of TCE oxidation proceeds according to the chain mechanism. At the temperature of 60 deg C in the dose rate range from 1.1015 to 1.5x1016 eV(cm3xs) radiation-chemical yield changes from 1.5x104 to 5x103 molecules/100 eV. It is found that the reaction rate practically does not depend upon oxygen concentration and is directly proportional to the TCE concentration and the dose rate. The process optimization is studied

  1. Electronic dissipation processes during chemical reactions on surfaces

    CERN Document Server

    Stella, Kevin

    2012-01-01

    Hauptbeschreibung Every day in our life is larded with a huge number of chemical reactions on surfaces. Some reactions occur immediately, for others an activation energy has to be supplied. Thus it happens that though a reaction should thermodynamically run off, it is kinetically hindered. Meaning the partners react only to the thermodynamically more stable product state within a mentionable time if the activation energy of the reaction is supplied. With the help of catalysts the activation energy of a reaction can be lowered. Such catalytic processes on surfaces are widely used in industry. A

  2. Vibration and Stability of 3000-hp, Titanium Chemical Process Blower

    OpenAIRE

    2003-01-01

    This 74-in-diameter blower had an overhung rotor design of titanium construction, operating at 50 pounds per square inch gauge in a critical chemical plant process. The shaft was supported by oil-film bearings and was directdriven by a 3000-hp electric motor through a metal disk type of coupling. The operating speed was 1780 rpm. The blower shaft and motor shaft motion was monitored by Bently Nevada proximity probes and a Model 3100 monitoring system.Although the blowers showed very satisfact...

  3. Chemical elements dynamic in the fermentation process of ethanol producing

    International Nuclear Information System (INIS)

    This paper provides useful information about the dynamics of chemical elements analysed by instrumental neutron activation analysis (INAA) and, found in the various segments of the fermentation process of producing ethanol from sugar cane. For this, a mass balance of Ce, Co, Cs, Eu, Fe, Hf, La, Sc, Sm, and Th, terrigenous elements, as well as Br, K, Rb, and Zn, sugar cane plant elements, has been demonstrated for the fermentation vats in industrial conditions of ethanol production. (author). 10 refs, 4 figs, 1 tab

  4. Large deviations for two scale chemical kinetic processes

    CERN Document Server

    Li, Tiejun

    2015-01-01

    We formulate the large deviations for a class of two scale chemical kinetic processes motivated from biological applications. The result is successfully applied to treat a genetic switching model with positive feedbacks. The corresponding Hamiltonian is convex with respect to the momentum variable as a by-product of the large deviation theory. This property ensures its superiority in the rare event simulations compared with the result obtained by formal WKB asymptotics. The result is of general interest to understand the large deviations for multiscale problems.

  5. Integrating chemical engineering fundamentals in the capstone process design project

    OpenAIRE

    von Solms, Nicolas; Woodley, John; Johnsson, Jan Erik; Abildskov, Jens

    2010-01-01

    All B.Eng. courses offered at the Technical University of Denmark (DTU) must now follow CDIO standards. The final “capstone” course in the B.Eng. education is Process Design, which for many years has been typical of chemical engineering curricula worldwide. The course at DTU typically has about 30 students. The B.Eng. education lasts for 3½ years (seven semesters), of which the 5th semester consists of practical training with a company and the final (7th) semester consists of a research proje...

  6. Relationship between snow microstructure and physical and chemical processes

    Directory of Open Access Journals (Sweden)

    T. Bartels-Rausch

    2012-11-01

    Full Text Available Ice and snow in the environment are important because they not only act as a host to rich chemistry but also provide a matrix for physical exchanges of contaminants within the ecosystem. This review discusses how the structure of snow influences both chemical reactivity and physical processes, which thereby makes snow a unique medium for study. The focus is placed on impacts of the presence of liquid and surface disorder using many experimental studies, simulations, and field observations from the molecular to the micro-scale.

  7. Chemical processes in the turbine and exhaust nozzle

    Energy Technology Data Exchange (ETDEWEB)

    Lukachko, S.P.; Waitz, I.A. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Aero-Environmental Lab.; Miake-Lye, R.C.; Brown, R.C.; Anderson, M.R. [Aerodyne Research, Inc., Billerica, MA (United States); Dawes, W.N. [University Engineering Dept., Cambridge (United Kingdom). Whittle Lab.

    1997-12-31

    The objective is to establish an understanding of primary pollutant, trace species, and aerosol chemical evolution as engine exhaust travels through the nonuniform, unsteady flow fields of the turbine and exhaust nozzle. An understanding of such processes is necessary to provide accurate inputs for plume-wake modeling efforts and is therefore a critical element in an assessment of the atmospheric effects of both current and future aircraft. To perform these studies, a numerical tool was developed combining the calculation of chemical kinetics and one-, two-, or three-dimensional (1-D, 2-D, 3-D) Reynolds-averaged flow equations. Using a chemistry model that includes HO{sub x}, NO{sub y}, SO{sub x}, and CO{sub x} reactions, several 1-D parametric analyses were conducted for the entire turbine and exhaust nozzle flow path of a typical advanced subsonic engine to understand the effects of various flow and chemistry uncertainties on a baseline 1-D result. These calculations were also used to determine parametric criteria for judging 1-D, 2-D, and 3-D modeling requirements as well as to provide information about chemical speciation at the nozzle exit plane. (author) 9 refs.

  8. Room temperature 57Fe Moessbauer spectroscopy of ordinary chondrites from the Atacama Desert (Chile): constraining the weathering processes on desert meteorites

    International Nuclear Information System (INIS)

    We report the results of a study on the weathering products of 21 meteorites found in the Atacama Desert (Chile) using room temperature 57Fe Moessbauer spectroscopy (MS). The meteorites are weathered ordinary chondrites (OCs) with unknown terrestrial ages and include the three chemical groups (H, L, and LL). We obtained the percentage of all the Fe-bearing phases for the primary minerals: olivine, pyroxene, troilite and Fe-Ni metal, and for the ferric alteration products (composed of the paramagnetic Fe3+ component and the magnetically ordered Fe3+ components) which gives the percentage of oxidation of the samples. From the Moessbauer absorption areas of these oxides, the terrestrial oxidation of the Atacama OC was found in the range from ∼5% to ∼60%. The amount of silicates as well as the opaques decreases at a constant rate with increasing oxidation level.

  9. Challenges in simulation of chemical processes in combustion furnaces

    Energy Technology Data Exchange (ETDEWEB)

    Hupa, M.; Kilpinen, P. [Aabo Akademi, Turku (Finland)

    1996-12-31

    The presentation gives an introduction to some of the present issues and problems in treating the complex chemical processes in combustion. The focus is in the coupling of the hydrocarbon combustion process with nitrogen oxide formation and destruction chemistry in practical furnaces or flames. Detailed kinetic modelling based on schemes of elementary reactions are shown to be a useful novel tool for identifying and studying the key reaction paths for nitrogen oxide formation and destruction in various systems. The great importance of the interaction between turbulent mixing and combustion chemistry is demonstrated by the sensitivity of both methane oxidation chemistry and fuel nitrogen conversion chemistry to the reactor and mixing pattern chosen for the kinetic calculations. The fluidized bed combustion (FBC) nitrogen chemistry involves several important heterogeneous reactions. Particularly the char in the bed plays an essential role. Recent research has advanced rapidly and the presentation proposes an overall picture of the fuel nitrogen reaction routes in circulating FBC conditions. (author)

  10. Development of microforming process combined with selective chemical vapor deposition

    Directory of Open Access Journals (Sweden)

    Koshimizu Kazushi

    2015-01-01

    Full Text Available Microforming has been received much attention in the recent decades due to the wide use of microparts in electronics and medical purpose. For the further functionalization of these micro devices, high functional surface with noble metals and nanomaterials are strongly required in bio- and medical fields, such as bio-sensors. To realize the efficient manufacturing process, which can deform the submillimeter scale bulk structure and can construct the micro to nanometer scale structures in one process, the present study proposes a combined process of microforming for metal foils with a selective chemical vapor deposition (SCVD on the active surface of work materials. To clarify the availability of this proposed process, the feasibility of SCVD of functional materials to active surface of titanium (Ti was investigated. CVD of iron (Fe and carbon nanotubes (CNTs which construct CNTs on the patterned surface of active Ti and non-active oxidation layer were conducted. Ti thin films on silicon substrate and Fe were used as work materials and functional materials, respectively. CNTs were grown on only Ti surface. Consequently, the selectivity of the active surface of Ti to the synthesis of Fe particles in CVD process was confirmed.

  11. Conversion of Lignocellulosic Biomass to Nanocellulose: Structure and Chemical Process

    Directory of Open Access Journals (Sweden)

    H. V. Lee

    2014-01-01

    Full Text Available Lignocellulosic biomass is a complex biopolymer that is primary composed of cellulose, hemicellulose, and lignin. The presence of cellulose in biomass is able to depolymerise into nanodimension biomaterial, with exceptional mechanical properties for biocomposites, pharmaceutical carriers, and electronic substrate’s application. However, the entangled biomass ultrastructure consists of inherent properties, such as strong lignin layers, low cellulose accessibility to chemicals, and high cellulose crystallinity, which inhibit the digestibility of the biomass for cellulose extraction. This situation offers both challenges and promises for the biomass biorefinery development to utilize the cellulose from lignocellulosic biomass. Thus, multistep biorefinery processes are necessary to ensure the deconstruction of noncellulosic content in lignocellulosic biomass, while maintaining cellulose product for further hydrolysis into nanocellulose material. In this review, we discuss the molecular structure basis for biomass recalcitrance, reengineering process of lignocellulosic biomass into nanocellulose via chemical, and novel catalytic approaches. Furthermore, review on catalyst design to overcome key barriers regarding the natural resistance of biomass will be presented herein.

  12. Optimization of chemical etching process in niobium cavities

    Energy Technology Data Exchange (ETDEWEB)

    Tajima, T. (Tsuyoshi); Trabia, M.; Culbreth, W.; Subramanian, S.

    2004-01-01

    Superconducting niobium cavities are important components of linear accelerators. Buffered chemical polishing (BCP) on the inner surface of the cavity is a standard procedure to improve its performance. The quality of BCP, however, has not been optimized well in terms of the uniformity of surface smoothness. A finite element computational fluid dynamics (CFD) model was developed to simulate the chemical etching process inside the cavity. The analysis confirmed the observation of other researchers that the iris section of the cavity received more etching than the equator regions due to higher flow rate. The baffle, which directs flow towards the walls of the cavity, was redesigned using optimization techniques. The redesigned baffle significantly improves the performance of the etching process. To verify these results an experimental setup for flow visualization was created. The setup consists of a high speed, high resolution CCD camera. The camera is positioned by a computer-controlled traversing mechanism. A dye injecting arrangement is used for tracking the fluid path. Experimental results are in general agreement with CFD and optimization results.

  13. Conversion of Lignocellulosic Biomass to Nanocellulose: Structure and Chemical Process

    Science.gov (United States)

    Lee, H. V.; Hamid, S. B. A.; Zain, S. K.

    2014-01-01

    Lignocellulosic biomass is a complex biopolymer that is primary composed of cellulose, hemicellulose, and lignin. The presence of cellulose in biomass is able to depolymerise into nanodimension biomaterial, with exceptional mechanical properties for biocomposites, pharmaceutical carriers, and electronic substrate's application. However, the entangled biomass ultrastructure consists of inherent properties, such as strong lignin layers, low cellulose accessibility to chemicals, and high cellulose crystallinity, which inhibit the digestibility of the biomass for cellulose extraction. This situation offers both challenges and promises for the biomass biorefinery development to utilize the cellulose from lignocellulosic biomass. Thus, multistep biorefinery processes are necessary to ensure the deconstruction of noncellulosic content in lignocellulosic biomass, while maintaining cellulose product for further hydrolysis into nanocellulose material. In this review, we discuss the molecular structure basis for biomass recalcitrance, reengineering process of lignocellulosic biomass into nanocellulose via chemical, and novel catalytic approaches. Furthermore, review on catalyst design to overcome key barriers regarding the natural resistance of biomass will be presented herein. PMID:25247208

  14. Increased chemical weathering of olivine in high-energy shelf seas can counteract human CO2 emissions and ocean acidification against a price well below that of CCS and other methods

    Science.gov (United States)

    de Boer, Poppe L.; Schuiling, Roelof D.

    2014-05-01

    In the reaction: Mg(Fe)2SiO4 (olivine) + 4 H2O 2 Mg(Fe)2+ + 4 OH- + H4SiO4, followed by 4 OH- + 4 CO2 4 HCO3-, CO2 is consumed, and Mg2+, Fe2+, H4SiO4 and HCO3- are produced. Contrary to the paradigm that olivine weathering in nature is a slow process, flume experiments show a fast reaction, consuming CO2, and raising the pH at short notice. Only under static conditions a silica coating develops that retards the reaction. In high-energy shallow marine environments such silica coatings are abraded so that the chemical reaction can continue. When kept in motion even large olivine grains and gravels, rubbing and bumping against each other and against other sediment grains, weather quickly. Experiments show that fine micron- to silt-sized olivine particles are produced, and that the chemical reaction is fast. The chemical weathering of 7 km3 olivine is needed on a yearly basis in order to compensate the human CO2 emissions. This seems much, but is of the same order of magnitude as the volume of fossil fuels (in oil equivalents ~10 km3) that are burnt annually. Olivine is readily available at the Earth' surface on all continents, and such volume of 7 km3 is exceeded by existing mines; e.g. the Bingham Canyon open pit mine in Utah has an excavated volume of 25 km3. Hydrocarbons, on the other hand, are commonly retrieved with great efforts, from great depths, and often at remote locations. Spreading of large amounts of olivine (and/or serpentinite) in high-energy shelf seas where coarse sand and gravel can be transported, will counteract human CO2 production by fossil fuel burning and ocean acidification against a price well below that of other methods; order of US 10.- per ton CO2. For example part of the continental shelf between the Shetland Isles and France, that is the Southern Bight of the North Sea, the English Channel and the Irish Sea, is covered with sand waves, and in and around the English Channel an area of well over 100,000 km2 experiences bed shear stresses

  15. Orbital forcing of glacial/interglacial variations in chemical weathering within the White Nile basin: stable-isotope and biomarker evidence from Lakes Victoria and Edward

    Science.gov (United States)

    Cockerton, Helen E.; Alayne Street-Perrott, F.; Barker, Philip A.; Leng, Melanie J.; Sloane, Hilary J.; Horstwood, Matthew S. A.; Snelling, Andrea

    2014-05-01

    The continental Si cycle on Quaternary time scales has been largely neglected. Emphasis has been placed on long-term geochemical processes of silicate-rock weathering and the resulting drawdown of atmospheric CO2, rather than on shorter-term biogenic processes occurring along the land-ocean continuum. Si-accumulating plants (notably tropical rainforest hardwoods, savanna and wetland grasses, and Papyrus) and aquatic organisms (such as diatoms and sponges in lakes, rivers and swamps) have the potential to take up, store and recycle significant amounts of Si, thereby modifying the riverine flux of Si to the oceans, the productivity of siliceous marine organisms and the rate of atmospheric CO2 drawdown on an orbital time scale. The main aim of this study was to investigate spatial and temporal patterns of Si cycling along the Nile system during the last 20ka BP. Utilising sediment cores from Lakes Victoria and Edward, coupled measurements of stable Si and O isotopes on cleaned diatom separates were employed to reconstruct millennial-scale variations in biotic Si cycling and palaeohydrology, respectively. Abundance ratios of lipid biomarkers (n-alkanes) were used to track major changes in terrestrial and aquatic ecosystems. The results have been interpreted in the light of multi-isotope analyses (2H,18O,30Si) of modern water samples collected along the courses of the modern White and Blue Niles during both wet- and dry-season conditions. During drier intervals (the Last Glacial Maximum and the late Holocene: high 18Odiatom), Si cycling was greatly reduced. Diminished vegetation cover, reduced biotic rock weathering, a declining soil stock of amorphous silica (ASi) and decreased runoff resulted in reduced dissolved silica (DSi) supply to the lakes in relation to aquatic demand (high 30Sidiatom). In contrast, enhanced monsoon rainfall (low 18Odiatom) during the early to mid-Holocene promoted a substantial increase in terrestrial biomass within the White Nile headwaters

  16. Nuclear criticality safety evaluation -- DWPF Late Wash Facility, Salt Process Cell and Chemical Process Cell

    International Nuclear Information System (INIS)

    The Savannah River Site (SRS) High Level Nuclear Waste will be vitrified in the Defense Waste Processing Facility (DWPF) for long term storage and disposal. This is a nuclear criticality safety evaluation for the Late Wash Facility (LWF), the Salt Processing Cell (SPC) and the Chemical Processing Cell (CPC). of the DWPF. Waste salt solution is processed in the Tank Farm In-Tank Precipitation (ITP) process and is then further washed in the DWPF Late Wash Facility (LWF) before it is fed to the DWPF Salt Processing Cell. In the Salt Processing Cell the precipitate slurry is processed in the Precipitate Reactor (PR) and the resultant Precipitate Hydrolysis Aqueous (PHA) produce is combined with the sludge feed and frit in the DWPF Chemical Process Cell to produce a melter feed. The waste is finally immobilized in the Melt Cell. Material in the Tank Farm and the ITP and Extended Sludge processes have been shown to be safe against a nuclear criticality by others. The precipitate slurry feed from ITP and the first six batches of sludge feed are safe against a nuclear criticality and this evaluation demonstrates that the processes in the LWF, the SPC and the CPC do not alter the characteristics of the materials to compromise safety

  17. Spreadsheets in chemical engineering education : a tool in process design and process integration

    OpenAIRE

    Ferreira, E. C.; Lima, Ricardo; Salcedo, Romualdo

    2004-01-01

    Recent developments in embedding numerical optimization procedures with linear and nonlinear solvers within a spreadsheet environment have greatly enhanced the use of these tools for teaching chemical process design and process integration. Student skills with respect to these topics are usually gained by complex and expensive modular simulators, e.g. ASPEN Plus® or algebraic tools such as GAMS® or AMPL®. However, modular simulators have a significant learning curve, and algebraic modeling la...

  18. Weather forecast

    CERN Document Server

    Courtier, P

    1994-01-01

    Weather prediction is performed using the numerical model of the atmosphere evolution.The evolution equations are derived from the Navier Stokes equation for the adiabatic part but the are very much complicated by the change of phase of water, the radiation porocess and the boundary layer.The technique used operationally is described. Weather prediction is an initial value problem and accurate initial conditions need to be specified. Due to the small number of observations available (105 ) as compared to the dimension of the model state variable (107),the problem is largely underdetermined. Techniques of optimal control and inverse problems are used and have been adapted to the large dimension of our problem. our problem.The at mosphere is a chaotic system; the implication for weather prediction is discussed. Ensemble prediction is used operationally and the technique for generating initial conditions which lead to a numerical divergence of the subsequent forecasts is described.

  19. Geochemistry of the Dissolved Load of the Changjiang Basin Rivers: Anthropogenic Impacts and Chemical Weathering, Evidences from Major Elements, Sr and B Isotopes

    Institute of Scientific and Technical Information of China (English)

    Benjamin Chetelat; LIU Cong-qiang

    2008-01-01

    @@ 1 Introduction Rivers provide a unique opportunity to have average information about chemical and physical erosion, about the major geochemical fractionations created by these major geological processes but also about the impact and disturbances of human activities on the Earth Engine.

  20. Leaching characteristics of Idaho Chemical Processing Plant calcines

    International Nuclear Information System (INIS)

    This report documents leaching studies conducted on two non-radioactive, pilot-plant calcines produced at the Idaho Chemical Processing Plant. The two pilot-plant calcines simulate radioactive calcine which may be produced in the New Waste Calcining Facility by blending high-level liquid waste and sodium-bearing liquid waste. The calcines were subjected to the Environmental Protection Agency's Extraction Procedure Toxicity Test and to a test based on the Materials Characterization Center's MCC-1 Static Leach Test. Following the protocol of these tests, leachates were obtained and analyzed for chemical composition to develop information about component mass loss and total mass loss. Surface analysis techniques were employed in an attempt to identify species that were leached from the calcines, but later precipitated during the MCC-1 tests. This report also documents leaching studies conducted on a radioactive fluorinel-sodium blend calcine produced in the New Waste Calcining Facility. This calcine was also subjected to a static leach test based on the MCC-1 test. The leachate was analyzed to develop information about total mass loss and leaching characteristics of radioactive species. 12 refs., 9 figs., 9 tabs

  1. Leaching characteristics of Idaho Chemical Processing Plant calcines

    Energy Technology Data Exchange (ETDEWEB)

    Chipman, N A

    1990-02-01

    This report documents leaching studies conducted on two non-radioactive, pilot-plant calcines produced at the Idaho Chemical Processing Plant. The two pilot-plant calcines simulate radioactive calcine which may be produced in the New Waste Calcining Facility by blending high-level liquid waste and sodium-bearing liquid waste. The calcines were subjected to the Environmental Protection Agency's Extraction Procedure Toxicity Test and to a test based on the Materials Characterization Center's MCC-1 Static Leach Test. Following the protocol of these tests, leachates were obtained and analyzed for chemical composition to develop information about component mass loss and total mass loss. Surface analysis techniques were employed in an attempt to identify species that were leached from the calcines, but later precipitated during the MCC-1 tests. This report also documents leaching studies conducted on a radioactive fluorinel-sodium blend calcine produced in the New Waste Calcining Facility. This calcine was also subjected to a static leach test based on the MCC-1 test. The leachate was analyzed to develop information about total mass loss and leaching characteristics of radioactive species. 12 refs., 9 figs., 9 tabs.

  2. Study of Chemical Decontamination Process for CRUD Removal

    International Nuclear Information System (INIS)

    Chalk River Unidentified Deposit (CRUD) is a technical term in nuclear engineering which is an accumulated material on external fuel rod cladding surfaces in nuclear power plants. It is a corrosion product which is composed of either dissolved ions or solid particles such as Ni, Fe and Co. It consists mainly of NiO and NiFe2O4. It can affect to reduce fuel lifetime, degrade heat transfer to the coolant, and threaten human health and environment. Therefore, decontamination process is essential for reducing occupational exposures, limiting potential releases and uptakes of radioactive materials, allowing the reuse of components, and facilitating waste management process. In this paper, we have conducted the synthesis of Cobalt ferrite as power foam to use for decontamination process. In dissolution test of Co ferrite and Ni ferrite, oxalic acid shows the most effective chemical decontamination reagent to remove the contaminants. Generally, the dissolved amount of cobalt and nickel increases at low pH condition and as the temperature goes higher, dissolved amount of cobalt and iron are much higher

  3. Study of Chemical Decontamination Process for CRUD Removal

    Energy Technology Data Exchange (ETDEWEB)

    Nam, Seongsik; Kim, Won-Seok; Kim, Jungjin; Um, Wooyong [POSTECH, Pohang (Korea, Republic of)

    2015-05-15

    Chalk River Unidentified Deposit (CRUD) is a technical term in nuclear engineering which is an accumulated material on external fuel rod cladding surfaces in nuclear power plants. It is a corrosion product which is composed of either dissolved ions or solid particles such as Ni, Fe and Co. It consists mainly of NiO and NiFe{sub 2}O{sub 4}. It can affect to reduce fuel lifetime, degrade heat transfer to the coolant, and threaten human health and environment. Therefore, decontamination process is essential for reducing occupational exposures, limiting potential releases and uptakes of radioactive materials, allowing the reuse of components, and facilitating waste management process. In this paper, we have conducted the synthesis of Cobalt ferrite as power foam to use for decontamination process. In dissolution test of Co ferrite and Ni ferrite, oxalic acid shows the most effective chemical decontamination reagent to remove the contaminants. Generally, the dissolved amount of cobalt and nickel increases at low pH condition and as the temperature goes higher, dissolved amount of cobalt and iron are much higher.

  4. Chemical Reactions in the Processing of Mosi2 + Carbon Compacts

    Science.gov (United States)

    Jacobson, Nathan S.; Lee, Kang N.; Maloy, Stuart A.; Heuer, Arthur H.

    1993-01-01

    Hot-pressing of MoSi2 powders with carbon at high temperatures reduces the siliceous grain boundary phase in the resultant compact. The chemical reactions in this process were examined using the Knudsen cell technique. A 2.3 wt pct oxygen MoSi2 powder and a 0.59 wt pct oxygen MoSi2 powder, both with additions of 2 wt pct carbon, were examined. The reduction of the siliceous grain boundary phase was examined at 1350 K and the resultant P(SiO)/P(CO) ratios interpreted in terms of the SiO(g) and CO(g) isobars on the Si-C-O predominance diagram. The MoSi2 + carbon mixtures were then heated at the hot-pressing temperature of 2100 K. Large weight losses were observed and could be correlated with the formation of a low-melting eutectic and the formation and vaporization of SiC.

  5. SDG-based Model Validation in Chemical Process Simulation

    Institute of Scientific and Technical Information of China (English)

    张贝克; 许欣; 马昕; 吴重光

    2013-01-01

    Signed direct graph (SDG) theory provides algorithms and methods that can be applied directly to chemical process modeling and analysis to validate simulation models, and is a basis for the development of a soft-ware environment that can automate the validation activity. This paper is concentrated on the pretreatment of the model validation. We use the validation scenarios and standard sequences generated by well-established SDG model to validate the trends fitted from the simulation model. The results are helpful to find potential problems, as-sess possible bugs in the simulation model and solve the problem effectively. A case study on a simulation model of boiler is presented to demonstrate the effectiveness of this method.

  6. Radon: Chemical and physical processes associated with its distribution

    International Nuclear Information System (INIS)

    Assessing the mechanisms which govern the distribution, fate, and pathways of entry into biological systems, as well as the ultimate hazards associated with the radon progeny and their secondary reaction products, depends on knowledge of their chemistry. Our studies are directed toward developing fundamental information which will provide a basis for modeling studies that are requisite in obtaining a complete picture of growth, attachment to aerosols, and transport to the bioreceptor and ultimate incorporation within. Our program is divided into three major areas of research. These include measurement of the determination of their mobilities, study of the role of radon progeny ions in affecting reactions, including study of the influence of the degree of solvation (clustering), and examination of the important secondary reaction products, with particular attention to processes leading to chemical conversion of either the core ions or the ligands as a function of the degree of clustering

  7. Chemical and Mechanical processes during burial diagenesis of chalk

    DEFF Research Database (Denmark)

    Borre, Mai Kirstine; Lind, Ida

    1998-01-01

    equal or larger influence on the textural development. In the chalk interval below, compaction is not the only porosity reducing agent but it has a larger influence on texture than concurrent recrystallization. Below 850 m grain-bridging cementation becomes important resulting in a lithified limestone......Burial diagenesis of chalk is a combination of mechanical compaction and chemical recrystallization as well as cementation. We have predicted the characteristic trends in specific surface resulting from these processes. The specific surface is normally measured by nitrogen adsorption but is here...... the Pacific, where a > 1 km thick package of chalk facies sediments accumulated from the Cretaceous to the present. In the upper 200-300 m the sediment is unconsolidated carbonate ooze, throughout this depth interval compaction is the principal porosity reducing agent, but recrystallization has an...

  8. Criticality and safeguards at the Idaho Chemical Processing Plant

    International Nuclear Information System (INIS)

    Reprocessing of high enriched irradiated reactor fuel at the Idaho Chemical Processing Plant (ICPP) presents significant potential problems to the Criticality Safety (CS) and Safeguards and Security (S and S) Sections. Two major interactions between these sections occurs when irradiated fuel is stored and fuel is dissolved. S and S is assigned the responsibility of maintaining a centralized records and reporting system which provides detailed, timely knowledge of the location, quantity and measurement uncertainties associated with accountable nuclear material, including uranium and plutonium. The Criticality Safety Section uses this information in providing criticality safety evaluations with support analyses, inspection, field surveillance and audits to ensure criticality safety implementation. The interactions of these sections has minimized operational constraints and maximized criticality safeguards controls

  9. Linear nonequilibrium thermodynamics of periodic processes and chemical oscillations

    CERN Document Server

    Heimburg, Thomas

    2016-01-01

    Onsager's phenomenological equations successfully describe irreversible thermodynamic processes. They assume a symmetric coupling matrix between thermodynamic fluxes and forces. It is easily shown that the antisymmetric part of a coupling matrix does not contribute to dissipation. Therefore, entropy production is exclusively governed by the symmetric matrix even in the presence of antisymmetric terms. In this work we focus on the antisymmetric contributions which describe isentropic oscillations and well-defined equations of motion. The formalism contains variables that are equivalent to momenta, and coefficients that are analogous to an inertial mass. We apply this formalism to simple problems such as an oscillating piston and the oscillation in an electrical LC-circuit. We show that isentropic oscillations are possible even close to equilibrium in the linear limit and one does not require far-from equilibrium situations. One can extend this formalism to other pairs of variables, including chemical systems w...

  10. Accelerating chemical database searching using graphics processing units.

    Science.gov (United States)

    Liu, Pu; Agrafiotis, Dimitris K; Rassokhin, Dmitrii N; Yang, Eric

    2011-08-22

    The utility of chemoinformatics systems depends on the accurate computer representation and efficient manipulation of chemical compounds. In such systems, a small molecule is often digitized as a large fingerprint vector, where each element indicates the presence/absence or the number of occurrences of a particular structural feature. Since in theory the number of unique features can be exceedingly large, these fingerprint vectors are usually folded into much shorter ones using hashing and modulo operations, allowing fast "in-memory" manipulation and comparison of molecules. There is increasing evidence that lossless fingerprints can substantially improve retrieval performance in chemical database searching (substructure or similarity), which have led to the development of several lossless fingerprint compression algorithms. However, any gains in storage and retrieval afforded by compression need to be weighed against the extra computational burden required for decompression before these fingerprints can be compared. Here we demonstrate that graphics processing units (GPU) can greatly alleviate this problem, enabling the practical application of lossless fingerprints on large databases. More specifically, we show that, with the help of a ~$500 ordinary video card, the entire PubChem database of ~32 million compounds can be searched in ~0.2-2 s on average, which is 2 orders of magnitude faster than a conventional CPU. If multiple query patterns are processed in batch, the speedup is even more dramatic (less than 0.02-0.2 s/query for 1000 queries). In the present study, we use the Elias gamma compression algorithm, which results in a compression ratio as high as 0.097. PMID:21696144

  11. Chemical Processing and Characterization of Fiber Reinforced Nanocomposite Silica Materials

    Science.gov (United States)

    Burnett, Steven Shannon

    Ultrasound techniques, acoustic and electroacoustic spectroscopy, are used to investigate and characterize concentrated fluid phase nanocomposites. In particular, the data obtained from ultrasound methods are used as tools to improve the understanding of the fundamental process chemistry of concentrated, multicomponent, nanomaterial dispersions. Silicon nitride nanofibers embedded in silica are particularly interesting for lightweight nanocomposites, because silicon nitride is isostructural to carbon nitride, a super hard material. However, the major challenge with processing these composites is retarding particle-particle aggregation, to maintain highly dispersed systems. Therefore, a systematic approach was developed to evaluate the affect of process parameters on particle-particle aggregation, and improving the chemical kinetics for gelation. From the acoustic analysis of the nanofibers, this thesis was able to deduce that changes in aspect ratio affects the ultrasound propagation. In particular, higher aspect ratio fibers attenuate the ultrasound wave greater than lower aspect fibers of the same material. Furthermore, our results confirm that changes in attenuation depend on the hydrodynamical interactions between particles, the aspect ratio, and the morphology of the dispersant. The results indicate that the attenuation is greater for fumed silica due to its elastic nature and its size, when compared to silica Ludox. Namely, the larger the size, the greater the attenuation. This attenuation is mostly the result of scattering loss in the higher frequency range. In addition, the silica nanofibers exhibit greater attenuation than their nanoparticle counterparts because of their aspect ratio influences their interaction with the ultrasound wave. In addition, this study observed how 3M NH 4 Cl's acoustic properties changes during the gelation process, and during that change, the frequency dependency deviates from the expected squared of the frequency, until the

  12. Chemical catalysis in biodiesel production (I): enzymatic catalysis processes

    International Nuclear Information System (INIS)

    There are some well known advantages related with the substitution of chemical catalysis by enzymatic catalysis processes.Some commercial immobilized lipases are useful for the catalysis of bio diesel reaction, which permits the achievement of high conversions and the recovery of high purity products, like a high quality glycerine. The main disadvantage of this alternative method is related with the last inactivation of the enzyme (by both the effect of the alcohol and the absorption of glycerol on catalyst surface), which added to the high cost of the catalyst, produces an unfavourable economical balance of the entire process. In the work the efficiency of two commercial immobilized lipases (Lipozyme TL IM y Novozyme 435 NNovozymes-Dinamarca) in the catalysis of the continuous transesterification of sunflower oil with different alcohols was studied. The intersolubility of the different mixturesinvolving reactans (S oil/alkyl esters/alcohol) and products (P mixtures with a higher content of 1% of glycerol,while for ethanol homogeneous mixtures were obtained at 12% of glycerol (44.44 12).Using and ethanolic substrate at the proportion S=19:75:6 and Lipozyme TL IM, it was possible to achieve a 98% of convertion to the corresponding biodiesel.When Novozymes 435 catalyzed the process it was possible to increase the oil concentration in the substrateaccording to proportion S=35:30:35, and a 78% conversion was obtained. The productivity shown by the firt enzyme was 70mg biodiesel g enzime-1, hora-1 while with the second one the productivity increased to 230. Results suggested that the convenient adjustement of substrate composition with the addition of biodiesel to reactants offers an efficient method for maximizing the enzyme productivity, hence improving the profitability of the enzymatic catalyzed process. (author)

  13. Integration of process design and controller design for chemical processes using model-based methodology

    DEFF Research Database (Denmark)

    Abd.Hamid, Mohd-Kamaruddin; Sin, Gürkan; Gani, Rafiqul

    2010-01-01

    constraints) problem. Accordingly the optimization problem is decomposed into four sub-problems: (i) pre-analysis, (ii) design analysis, (iii) controller design analysis, and (iv) final selection and verification, which are relatively easier to solve. The methodology makes use of thermodynamic...... satisfy design, control and cost criteria. The advantage of the proposed methodology is that it is systematic, makes use of thermodynamic-process knowledge and provides valuable insights to the solution of IPDC problems in chemical engineering practice....

  14. Chemical inhibition of PCDD/F formation in incineration processes.

    Science.gov (United States)

    Ruokojärvi, Päivi H; Asikainen, Arja H; Tuppurainen, Kari A; Ruuskanen, Juhani

    2004-06-01

    This review summarises results of our pilot-scale experiments to find suitable inhibitors for preventing the formation of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) during waste incineration and to specify the role of the main factors affecting the inhibition process, and is based on doctoral dissertation of Ruokojaärvi (2002). Results of previous experiments reported by other researchers are also presented and compared with ours. The detailed aims of our experiments were (1) to compare the effects of different inhibitors on PCDD/F formation during incineration in a pilot plant, (2) to investigate the role of the particle size distribution of the flue gas on the inhibition of PCDD/Fs, and (3) to find the main parameters affecting PCDD/F inhibition in waste incineration. Prevention of the formation of PCDD/Fs with chemical inhibitors and the effects of different supply points, feed temperatures and process parameters were studied in a pilot scale incinerator (50 kW) using light heating oil and refuse-derived fuel as test fuels. Various concentrations of the gaseous inhibitors (sulfur dioxide, ammonia, dimethylamine and methyl mercaptan) were sprayed into the flue gases after the furnace, in addition to which urea was dissolved in water and injected in at different concentrations. The residence time of the flue gas between the furnace and the PCDD/F sampling point was varied in the tests. In another set of urea tests, urea-water solutions at three concentrations were mixed with the RDF prior to incineration. PCDD/F and chlorophenol concentrations, together with other flue gas parameters (e.g. temperature, O2, CO, CO2 and NO), were analysed in the cooling flue gases. The gaseous and liquid inhibitors both notably reduced PCDD/F concentrations in the flue gas, the reductions achieved with the gaseous inhibitors varying from 50 to 78%, with dimethyl amine the most effective, while that produced with urea was up to 90%. The PCDD/F reductions were

  15. Chemical inhibition of PCDD/F formation in incineration processes

    International Nuclear Information System (INIS)

    This review summarises results of our pilot-scale experiments to find suitable inhibitors for preventing the formation of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) during waste incineration and to specify the role of the main factors affecting the inhibition process, and is based on a doctoral dissertation. Results of previous experiments reported by other researchers are also presented and compared with ours. The detailed aims of our experiments were (1) to compare the effects of different inhibitors on PCDD/F formation during incineration in a pilot plant, (2) to investigate the role of the particle size distribution of the flue gas on the inhibition of PCDD/Fs, and (3) to find the main parameters affecting PCDD/F inhibition in waste incineration. Prevention of the formation of PCDD/Fs with chemical inhibitors and the effects of different supply points, feed temperatures and process parameters were studied in a pilot scale incinerator (50 kW) using light heating oil and refuse-derived fuel as test fuels. Various concentrations of the gaseous inhibitors (sulfur dioxide, ammonia, dimethylamine and methyl mercaptan) were sprayed into the flue gases after the furnace, in addition to which urea was dissolved in water and injected in at different concentrations. The residence time of the flue gas between the furnace and the PCDD/F sampling point was varied in the tests. In another set of urea tests, urea-water solutions at three concentrations were mixed with the RDF prior to incineration. PCDD/F and chlorophenol concentrations, together with other flue gas parameters (e.g. temperature, O2, CO, CO2 and NO), were analysed in the cooling flue gases. The gaseous and liquid inhibitors both notably reduced PCDD/F concentrations in the flue gas, the reductions achieved with the gaseous inhibitors varying from 50 to 78%, with dimethyl amine the most effective, while that produced with urea was up to 90%. The PCDD/F reductions were greater at increased

  16. Hydrological processes and water resources management in a dryland environment III: Groundwater recharge and recession in a shallow weathered aquifer

    OpenAIRE

    Butterworth, J. A.; Macdonald, D. M. J.; Bromley, J.; Simmonds, L. P.; Lovell, C. J.; Mugabe, F.

    1999-01-01

    In crystalline basement regions of Africa, shallow weathered aquifers provide vital water resources for rural communities. To quantify evidence of the behaviour of these shallow aquifers, groundwater levels were observed at a network of 65 boreholes within the Romwe Catchment in southern Zimbabwe. Soil moisture was monitored at selected sites. Groundwater hydrographs showed considerable spatial and temporal variation. Where the soil profile was freely draining, groundwater levels typically re...

  17. Hydrological processes and water resources management in a dryland environment III: Groundwater recharge and recession in a shallow weathered aquifer

    OpenAIRE

    J. A. Butterworth; D. M. J. Macdonald; Bromley, J.; Simmonds, L. P.; C. J. Lovell; Mugabe, F.

    2002-01-01

    In crystalline basement regions of Africa, shallow weathered aquifers provide vital water resources for rural communities. To quantify evidence of the behaviour of these shallow aquifers, groundwater levels were observed at a network of 65 boreholes within the Romwe Catchment in southern Zimbabwe. Soil moisture was monitored at selected sites. Groundwater hydrographs showed considerable spatial and temporal variation. Where the soil profile was freely draining, groundwater levels typically re...

  18. Changes in lead and zinc lability during weathering-induced acidification of desert mine tailings: Coupling chemical and micro-scale analyses

    Science.gov (United States)

    Hayes, Sarah M.; White, Scott A.; Thompson, Thomas L.; Maier, Raina M.; Chorover, Jon

    2009-01-01

    Desert mine tailings may accumulate toxic metals in the near surface centimeters because of low water through-flux rates. Along with other constraints, metal toxicity precludes natural plant colonization even over decadal time scales. Since unconsolidated particles can be subjected to transport by wind and water erosion, potentially resulting in direct human and ecosystem exposure, there is a need to know how the lability and form of metals change in the tailings weathering environment. A combination of chemical extractions, X-ray diffraction, micro-X-ray fluorescence spectroscopy, and micro-Raman spectroscopy were employed to study Pb and Zn contamination in surficial arid mine tailings from the Arizona Klondyke State Superfund Site. Initial site characterization indicated a wide range in pH (2.5 to 8.0) in the surficial tailings pile. Ligand-promoted (DTPA) extractions, used to assess plant-available metal pools, showed decreasing available Zn and Mn with progressive tailings acidification. Aluminum shows the inverse trend, and Pb and Fe show more complex pH dependence. Since the tailings derive from a common source and parent mineralogy, it is presumed that variations in pH and “bioavailable” metal concentrations result from associated variation in particle-scale geochemistry. Four sub-samples, ranging in pH from 2.6 to 5.4, were subjected to further characterization to elucidate micro-scale controls on metal mobility. With acidification, total Pb (ranging from 5 – 13 g kg−1) was increasingly associated with Fe and S in plumbojarosite aggregates. For Zn, both total (0.4 – 6 g kg−1) and labile fractions decreased with decreasing pH. Zinc was found to be primarily associated with the secondary Mn phases manjiroite and chalcophanite. The results suggest that progressive tailings acidification diminishes the overall lability of the total Pb and Zn pools. PMID:20161492

  19. Three-dimensional chemical structure of the INEL aquifer system near the Idaho Chemical Processing Plant

    International Nuclear Information System (INIS)

    Sampling and analysis from the Snake River Plain aquifer using a stainless-steel and teflon constructed straddle-packer system has established detailed vertical profiles of aquifer chemistry from three wells near a major source of low-level waste injection at the Idaho Chemical Processing Plant. Multiple intervals, varying from 4.6 to 6.1 m in length, were sampled between the water table (140.5 mbls - meters below land surface), and approximately 200 mbls to obtain a wide spectrum of metals, anions, radiological and organic components analyses. Measurements were also made at the well sites of important transient parameters (T, Eh, Fe3+, Fe2+, DO and SC). The principal purpose of this ongoing work is to improve our understanding of the third (i.e. vertical) dimension of aquifer chemistry at the INEL as a basis for critically evaluating site-wide monitoring procedures, and, ultimately, for improving fate and transport models for aquifer contaminants within basalt-hosted aquifers. Chemical and radiological data indicates that substantial systematic vertical and lateral variations occur in the aquifer hydrochemistry - in particular for conservative radiological nuclide concentrations. Radiological data define a three-layered zonation. Ground water within upper and lower zones contain up to 10 times higher concentrations of H-3 and I-129 than in the middle zone. Sr-90 activity is decoupled from H-3 and I-129-relatively high activity was detected within the upper zone nearest the ICPP, but activities elsewhere are very low. 27 refs., 4 figs., 1 tab

  20. Research on weathering and biomarkers in heavy fuel oil

    International Nuclear Information System (INIS)

    The fate of oil spilled in the ocean depends on several physicochemical and biological factors such as evaporation, dissolution, microbial degradation and photo-oxidation. These weathering processes decrease the low molecules in spilled oils which reduces the harmful effects of spilled oil to the ocean and biota near the spill. In addition to changing the composition of the oil, some weathering processes are key to identifying the spilled oil. As such, the relationship between the weathering processes and the changes in oil composition must be well understood. This paper used gas chromatography and mass spectrometry (GC/MS) to analyze changes of chemical components in heavy fuel oil by weathering in static seawater. The major alkanes of heavy fuel oil include C8 to C33, while the major aromatics include benzene, naphthalene, phenanthrene and dibenzothiophene. After 24 weeks of weathering in seawater, the alkanes from n-C8 to n-C15 evaporated in order of increasing carbon number. The susceptibility of n-alkanes was correlated with carbon numbers. The aromatics evaporated in order of increasing carbon and ring number as weathering time increased. 8 refs., 3 tabs., 5 figs

  1. The Idaho Chemical Processing Plant Special Nuclear Material vault upgrade

    International Nuclear Information System (INIS)

    This document discusses storage space in a Special Nuclear Material (SNM) product storage vault at the Idaho Chemical Processing Plant (ICPP) which has been recently expanded by approximately 175%. This expansion required a minimum of space and funding and resulted in a large increase in net storage capacity. Security for the additional storage is provided by standard intrusion sensors and by a real-time monitoring system, which monitors the weight of the material as it rests on weight sensors (load cells). The monitoring system also feeds weight data to a Safeguards processor which provides further confidence to Safeguards personnel. The Department of Energy requirements for bimonthly inventories for SNM stored in a particular part of this facility have been eliminated because of the guarantees provided by a real-time monitoring system. A higher efficiency has been obtained by using the expensive real estate inside a hardened product storage vault. This project has provided the ICPP with a relatively inexpensive vault upgrade and when product material is placed in this area of the vault the manpower requirements to inventory it will be reduced, resulting in a net reduction in plant worker radiation exposure

  2. NATO Advanced Study Institute on Chemical Transport in Melasomatic Processes

    CERN Document Server

    1987-01-01

    As indicated on the title page, this book is an outgrowth of the NATO Advanced Study Institute (ASI) on Chemical Transport in Metasomatic Processes, which was held in Greece, June 3-16, 1985. The ASI consisted of five days of invited lectures, poster sessions, and discussion at the Club Poseidon near Loutraki, Corinthia, followed by a two-day field trip in Corinthia and Attica. The second week of the ASI consisted of an excursion aboard M/S Zeus, M/Y Dimitrios II, and the M/S Irini to four of the Cycladic Islands to visit, study, and sample outstanding exposures of metasomatic activity on Syros, Siphnos, Seriphos, and Naxos. Nine­ teen invited lectures and 10 session chairmen/discussion leaders participated in the ASI, which was attended by a total of 92 professional scientists and graduate stu­ dents from 15 countries. Seventeen of the invited lectures and the Field Excursion Guide are included in this volume, together with 10 papers and six abstracts representing contributed poster sessions. Although more...

  3. COLUMN, 1-D Migration for Various Physical Chemical Processes

    International Nuclear Information System (INIS)

    1 - Description of problem or function: COLUMN2 is designed for studies of the effects various physicochemical processes on migration in one dimension. It solves the transport equation and can take into account dispersion, sorption, ion exchange, first and second order homogeneous chemical reactions. Spatial variations of input pulses and retention factors are possible. 2 - Method of solution: The Method of solution is based on a finite difference discretion followed by the application of the method of characteristics and two separate grid systems. 3 - Restrictions on the complexity of the problem: For computational reasons the number of components has been limited to 5 and the maximum number of second order reactions is 10. However, a re-dimensioning of all relevant arrays will allow for any number of components and reactions desired. Arrays should never be dimensioned larger than needed in order to save computation time. Five components and 10 second order reactions may seem a small number. However, larger simulations are often divided into smaller sub-problems for clarification purposes. The maximum number of grid points, default value 801, may be enlarged to re-dimensioning all relevant arrays

  4. Chemical reactions during the thermal processing of borazene polymers

    International Nuclear Information System (INIS)

    A class of borazene polymers was developed which consists of a two-dimensional array of six-membered borazene rings with the borons of adjacent borazene rings separated by -NH- groups. Pyrolysis of these polymers above ∼1000 degrees C leads to crystalline graphite-like boron nitride (h-BN). The thermal chemistry of thin films of one polymer deposited on KOH-etched aluminum was examined by thermal decomposition mass spectroscopy (TDMS) and thermal gravimetric analysis (TGA) and the gas evolution chemistry was found to be essentially complete at temperatures less than 400 degrees C. All products desorb with the same temperature profile and the major desorbing species are NH3 and N2, consistent with a loss of excess nitrogen and hydrogen in the polymer, and HCI from decomposition of byproducts of the synthesis step. Since the formation of ordered crystalline h-BN films requires heating to temperatures of the order of 1000 degrees C, whereas the gas evolution chemistry is complete by roughly 400 degrees C, it is concluded that gas evolution chemical processes are not rate limiting in BN ceramic production

  5. Space Weather- Physics and Effects

    CERN Document Server

    Bothmer, Volker

    2007-01-01

    This book is a state-of-the-art review on the physics of space weather and on space weather impacts on human technology, including manned spaceflight. With contributions from a team of international experts, this comprehensive work covers all aspects of space weather physical processes, and all known aspects of space hazards from humans, both in space and on Earth. Space Weather - Physics and Effects provides the first comprehensive, scientific background of space storms caused by the sun and its impact on geospace focuses on weather issues that have become vital for the development of nationwide technological infrastructures explains magnetic storms on Earth, including the effects of EUV radiation on the atmosphere is an invaluable aid in establishing real-time weather forecasts details the threat that solar effects might have on modern telecommunication systems, including national power grid systems, aircraft and manned spaceflight.

  6. Weather Forecasting Systems and Methods

    Science.gov (United States)

    Mecikalski, John (Inventor); MacKenzie, Wayne M., Jr. (Inventor); Walker, John Robert (Inventor)

    2014-01-01

    A weather forecasting system has weather forecasting logic that receives raw image data from a satellite. The raw image data has values indicative of light and radiance data from the Earth as measured by the satellite, and the weather forecasting logic processes such data to identify cumulus clouds within the satellite images. For each identified cumulus cloud, the weather forecasting logic applies interest field tests to determine a score indicating the likelihood of the cumulus cloud forming precipitation and/or lightning in the future within a certain time period. Based on such scores, the weather forecasting logic predicts in which geographic regions the identified cumulus clouds will produce precipitation and/or lighting within during the time period. Such predictions may then be used to provide a weather map thereby providing users with a graphical illustration of the areas predicted to be affected by precipitation within the time period.

  7. Chemical and Process Integration for Environmental Assessment – Development and Evaluation of a Chemical Recycling Concept for Plastic Waste

    OpenAIRE

    Kaggerud, Kristin Herder

    2007-01-01

    The thesis focuses on systems oriented methods in conceptual design and analysis of chemical processes, both with respect to environmental performance. The areas of process synthesis and process systems engineering offer a considerable number of methodologies and tools for designing integrated production systems, ranging from individual processes to total sites. In this thesis the well established tools, life cycle assessment (LCA) and process integration (PI), have been applied in evaluation...

  8. Exploring clouds, weather, climate, and modeling using bilingual content and activities from the Windows to the Universe program and the Center for Multiscale Modeling of Atmospheric Processes

    Science.gov (United States)

    Foster, S. Q.; Johnson, R. M.; Randall, D.; Denning, S.; Russell, R.; Gardiner, L.; Hatheway, B.; Genyuk, J.; Bergman, J.

    2008-12-01

    The need for improving the representation of cloud processes in climate models has been one of the most important limitations of the reliability of climate-change simulations. Now in its third year, the National Science Foundation-funded Center for Multi-scale Modeling of Atmospheric Processes (CMMAP) at Colorado State University is addressing this problem through a revolutionary new approach to representing cloud processes on their native scales, including the cloud-scale interaction processes that are active in cloud systems. CMMAP has set ambitious education and human-resource goals to share basic information about the atmosphere, clouds, weather, climate, and modeling with diverse K-12 and public audiences through its affiliation with the Windows to the Universe (W2U) program at University Corporation for Atmospheric Research (UCAR). W2U web pages are written at three levels in English and Spanish. This information targets learners at all levels, educators, and families who seek to understand and share resources and information about the nature of weather and the climate system, and career role models from related research fields. This resource can also be helpful to educators who are building bridges in the classroom between the sciences, the arts, and literacy. Visitors to the W2U's CMMAP web portal can access a beautiful new clouds image gallery; information about each cloud type and the atmospheric processes that produce them; a Clouds in Art interactive; collections of weather-themed poetry, art, and myths; links to games and puzzles for children; and extensive classroom- ready resources and activities for K-12 teachers. Biographies of CMMAP scientists and graduate students are featured. Basic science concepts important to understanding the atmosphere, such as condensation, atmosphere pressure, lapse rate, and more have been developed, as well as 'microworlds' that enable students to interact with experimental tools while building fundamental knowledge

  9. Book of abstracts Chemical Engineering: IV All-Russian Conference on chemical engineering, All-Russian Youth Conference on chemical engineering, All-Russian school on chemical engineering for young scientists and specialists. Chemical engineering of nanomaterials. Energy- and resource-saving chemical-engineering processes and problems of their intensification. Processes and apparatuses of chemical engineering, chemical cybernetics. Ecological problems of chemical engineering and related fields

    International Nuclear Information System (INIS)

    In the given volume of abstracts of the IV All-Russian Conference on chemical engineering, All-Russian Youth Conference on chemical engineering, All-Russian school on chemical engineering for young scientists and specialists (Moscow, March 18-23, 2012) there are the abstracts of the reports concerning chemical engineering of nanomaterials, energy- and resource-saving chemical-engineering processes, processes and apparatuses of chemical engineering, chemical cybernetics, ecological problems of chemical engineering and related fields. The abstracts deal with state-of-the-art and future development of theoretical and experimental investigations as well as with experience in practical realization of development works in the field of chemical engineering and relative areas

  10. Statistical process control support during Defense Waste Processing Facility chemical runs

    International Nuclear Information System (INIS)

    The Product Composition Control System (PCCS) has been developed to ensure that the wasteforms produced by the Defense Waste Processing Facility (DWPF) at the Savannah River Site (SRS) will satisfy the regulatory and processing criteria that will be imposed. The PCCS provides rigorous, statistically-defensible management of a noisy, multivariate system subject to multiple constraints. The system has been successfully tested and has been used to control the production of the first two melter feed batches during DWPF Chemical Runs. These operations will demonstrate the viability of the DWPF process. This paper provides a brief discussion of the technical foundation for the statistical process control algorithms incorporated into PCCS, and describes the results obtained and lessons learned from DWPF Cold Chemical Run operations. The DWPF will immobilize approximately 130 million liters of high-level nuclear waste currently stored at the Site in 51 carbon steel tanks. Waste handling operations separate this waste into highly radioactive sludge and precipitate streams and less radioactive water soluble salts. (In a separate facility, soluble salts are disposed of as low-level waste in a mixture of cement slag, and flyash.) In DWPF, the precipitate steam (Precipitate Hydrolysis Aqueous or PHA) is blended with the insoluble sludge and ground glass frit to produce melter feed slurry which is continuously fed to the DWPF melter. The melter produces a molten borosilicate glass which is poured into stainless steel canisters for cooling and, ultimately, shipment to and storage in a geologic repository

  11. Chemical Processes Related to Combustion in Fluidised Bed

    Energy Technology Data Exchange (ETDEWEB)

    Steenari, Britt-Marie; Lindqvist, Oliver [Chalmers Univ. of Technology, Goeteborg (Sweden). Dept. of Environmental Inorganic Chemistry

    2002-12-01

    with evaluation of other biomass ash particles and, as an extension, the speciation of Cu and Zn will be studied as well. Ash fractions from combustion of MSW in a BFB boiler have been investigated regarding composition and leaching properties, i.e. environmental impact risks. The release of salts from the cyclone ash fraction can be minimised by the application of a simple washing process, thus securing that the leaching of soluble substances stays within the regulative limits. The MSW ash - water systems contain some interesting chemical issues, such as the interactions between Cr(VI) and reducing substances like Al-metal. The understanding of such chemical processes is important since it gives a possibility to predict effects of a change in ash composition. An even more detailed understanding of interactions between a solution containing ions and particle surfaces can be gained by theoretical modelling. In this project (and with additional unding from Aangpannefoereningens Forskningsstiftelse) a theoretical description of ion-ion interactions and the solid-liquid-interface has been developed. Some related issues are also included in this report. The publication of a paper on the reactions of ammonia in the presence of a calcining limestone surface is one of them. A review paper on the influence of combustion conditions on the properties of fly ash and its applicability as a cement replacement in concrete is another. The licentiate thesis describing the sampling and measurement of Cd in flue gas is also included since it was finalised during the present period. A co-operation project involving the Geology Dept. at Goeteborg Univ. and our group is briefly discussed. This project concerns the utilisation of granules produced from wood ash and dolomite as nutrient source for forest soil. Finally, the plans for our flue gas simulator facility are discussed.

  12. The Status of GNSS Data Processing Systems to Estimate Integrated Water Vapour for Use in Numerical Weather Prediction Models

    OpenAIRE

    Ahmed, Furqan; Teferle, Felix Norman; Bingley, Richard; Laurichesse, Denis

    2015-01-01

    Modern Numerical Weather Prediction (NWP) models make use of the GNSS-derived Zenith Total Delay (ZTD) or Integrated Water Vapour (IWV) estimates to enhance the quality of their forecasts. Usually, the ZTD is assimilated into the NWP models on 3-hourly to 6-hourly intervals but with the advancement of NWP models towards higher update rates e.g. 1-hourly cycling in the Rapid Update Cycle (RUC) NWP, it has become of high interest to estimate ZTD on sub-hourly intervals. In turn, this imposes...

  13. Experimental investigation of Mars meandering rivers: Chemical precipitation process

    Science.gov (United States)

    Kim, W.; Lim, Y.; Cleveland, J.; Reid, E.; Jew, C.

    2014-12-01

    On Earth, meandering streams occur where the banks are resistant to erosion, which enhances narrow and deep channels. Often this is because the stream banks are held firm by vegetation. The ancient, highly sinuous channels with cutoffs found on Mars are enigmatic because vegetation played no role in providing bank cohesion and enhancing fine sediment deposition. Possible causes of the meandering therefore include ice under permafrost conditions and chemical processes. We conducted carbonate flume experiments to investigate possible mechanisms creating meandering channels other than vegetation. The experiment includes a tank that dissolves limestone by adding CO2 gas and produces artificial spring water, peristaltic pumps to drive water through the system, a heater to control the temperature of the spring water, and a flume where carbonate sediment deposits. Spring water containing dissolved calcium and carbonate ions moves through a heater to increase temperature, and then into the flume. The flume surface is open to the air to allow CO2 degassing, decrease temperature, and increase pH, which promotes carbonate precipitation. A preliminary experiment was done and successfully created a meander pattern that evolved over a 3-day experiment. The experiment showed lateral migration of the bend and avulsion of the stream, similar to a natural meander. The lateral variation in flow speed increased the local residence time of water, thus increasing the degassing of CO2 on the two sides of the flow and promoting more precipitation. This enhanced precipitation on the sides provided a mechanism to build levees along the channel and created a stream confined in a narrow path. This mechanism also potentially applies to Earthly single thread and/or meandering rivers developed and recorded before vegetation appeared on Earth's surface.

  14. Technical safety appraisal of the Idaho Chemical Processing Plant

    International Nuclear Information System (INIS)

    On June 27, 1989, Secretary of Energy, Admiral James D. Watkins, US Navy (Retired), announced a 10-point initiative to strengthen environment, safety, and health (ES ampersand H) programs and waste management operations in the Department of Energy (DOE). One of the initiatives involved conducting independent Tiger Team Assessments (TTA) at DOE operating facilities. A TTA of the Idaho National Engineering Laboratory (INEL) was performed during June and July 1991. Technical Safety Appraisals (TSA) were conducted in conjunction with the TTA as its Safety and Health portion. However, because of operational constraints the the Idaho Chemical Processing Plant (ICPP), operated for the DOE by Westinghouse Idaho Nuclear Company, Inc. (WINCO), was not included in the Safety and Health Subteam assessment at that time. This TSA, conducted April 12 - May 8, 1992, was performed by the DOE Office of Performance Assessment to complete the normal scope of the Safety and Health portion of the Tiger Team Assessment of the Idaho National Engineering Laboratory. The purpose of TSAs is to evaluate and strengthen DOE operations by verifying contractor compliance with DOE Orders, to assure that lessons learned from commercial operations are incorporated into facility operations, and to stimulate and encourage pursuit of excellence; thus, the appraisal addresses more issues than would be addressed in a strictly compliance-oriented appraisal. A total of 139 Performance Objectives have been addressed by this appraisal in 19 subject areas. These 19 areas are: organization and administration, quality verification, operations, maintenance, training and certification, auxiliary systems, emergency preparedness, technical support, packaging and transportation, nuclear criticality safety, safety/security interface, experimental activities, site/facility safety review, radiological protection, worker safety and health compliance, personnel protection, fire protection, medical services and natural

  15. Road Weather and Connected Vehicles

    Science.gov (United States)

    Pisano, P.; Boyce, B. C.

    2015-12-01

    road weather sensors on their maintenance fleet vehicles to collect vehicular and meteorological data. Data from all three states is sent to a processing system called the Pikalert® Vehicle Data Translator (VDT) that quality checks and uses the data to infer current and forecasted weather conditions.

  16. Progress and energy effects of weathering and degassing of solid fuels

    Energy Technology Data Exchange (ETDEWEB)

    Postrzednik, S. [Technical University of Silesia, Gliwice (Poland). Inst. of Thermal Engineering

    1998-12-31

    The main phenomenon of weathering and selfheating of solid fuels is the low temperature oxidation of the combustible substance. Also of importance is the degassing and low temperature devolatilization of the solid fuel and the transport of water vapour through the solid fuel bed. Energy losses and the ecological aspects of solid fuel weathering (self heating, endogenous fires, gas explosions) are the main subjects of this work. A method of the energy consumption determination in the weathering process of solid fuel, treated as a physical and chemical process, by using the kinetic relations of the main phenomena is proposed. 7 figs., 5 refs.

  17. Progress and energy effects of degassing and weathering of solid fuels

    Energy Technology Data Exchange (ETDEWEB)

    Postrzednik, S. [Technical University of Silesia, Gliwice (Poland). Inst. of Thermal Engineering

    1997-12-31

    The main phenomenon of weathering and self heating of solid fuels is the low temperature oxidation of the combustible substance, the second of importance is the degassing and low temperature devolatilization of solid fuel and transport of water vapour through the solid fuel bed. Energy losses and ecological aspects of solid fuel weathering (self heating, endogenous fires, gas explosions) are the main topics in this paper. A method of determining energy consumption in weathering process of solid fuel, treated as a physical and chemical process, by using the kinetic relations of main phenomena is proposed. 5 refs., 7 figs.

  18. National toxicology program chemical nomination and selection process

    Energy Technology Data Exchange (ETDEWEB)

    Selkirk, J.K. [National Institute of Environmental Health Sciences, Research Triangle Park, NC (United States)

    1990-12-31

    The National Toxicology Program (NTP) was organized to support national public health programs by initiating research designed to understand the physiological, metabolic, and genetic basis for chemical toxicity. The primary mandated responsibilities of NTP were in vivo and vitro toxicity testing of potentially hazardous chemicals; broadening the spectrum of toxicological information on known hazardous chemicals; validating current toxicological assay systems as well as developing new and innovative toxicity testing technology; and rapidly communicating test results to government agencies with regulatory responsibilities and to the medical and scientific communities. 2 figs.

  19. Weathering effects on the structure and reactivity of US coals: Final report, July 15, 1984-July 14, 1987. [Many data

    Energy Technology Data Exchange (ETDEWEB)

    Meuzelaar, H.L.C.; Hill, G.R.; Yun, Yongseung; Jakab, E.; Windig, W.; Urban, D.; Yon, Kyung Yol; Oestreich, J.; East, J.

    1987-01-01

    This report covers the work performed from July 1984 to July 1987 under the project entitled ''Weathering Effects on Structure and Reactivity of US Coals'' (grant number FG22-84PC70798). The main objectives of the study were to investigate the structural changes in coal during the weathering process as well as to develop a simple, reliable weathering index, which can monitor indirectly the weathering-induced changes in physical and chemical properties. Although there have been numerous publications on structure and reactivity of coal, most data reported in the literature thus far have been obtained on coal samples of uncertain weathering status and therefore need to be interpreted with great caution. Weathering has a profound effect on many important coal properties such as heating value, caking characteristics, acidity, flotability and reactivity in liquefaction, combustion and gasification processes. The objective of developing a weathering index is to predict these coal property changes due to weathering without resorting to real-time measurements or pilot plant runs. This report is comprised of four main chapters: I. Structural Changes due to Weathering; II. Material Balance in Weathering Process; III. Development of a Reliable Weathering Index; and IV. Proposed Weathering Mechanisms. A battery of sophisticated analytical tools and techniques was employed during this study. Pyrolysis mass spectrometry in time-integrated, as well as in time-resolved modes with computer-aided data analysis techniques (such as factor and discriminant analysis), gas chromatography, thermogravimetry/mass spectrometry and solvent extraction were used for determining the role of oxygen during the weathering process. Pyrolysis mass spectrometry, Free Swelling Index and a novel slurry pH technique were employed as weathering indicators. 170 refs.

  20. New trajectory-driven aerosol and chemical process model Chemical and Aerosol Lagrangian Model (CALM

    Directory of Open Access Journals (Sweden)

    P. Tunved

    2010-11-01

    Full Text Available A new Chemical and Aerosol Lagrangian Model (CALM has been developed and tested. The model incorporates all central aerosol dynamical processes, from nucleation, condensation, coagulation and deposition to cloud formation and in-cloud processing. The model is tested and evaluated against observations performed at the SMEAR II station located at Hyytiälä (61° 51' N, 24° 17' E over a time period of two years, 2000–2001. The model shows good agreement with measurements throughout most of the year, but fails in reproducing the aerosol properties during the winter season, resulting in poor agreement between model and measurements especially during December–January. Nevertheless, through the rest of the year both trends and magnitude of modal concentrations show good agreement with observation, as do the monthly average size distribution properties. The model is also shown to capture individual nucleation events to a certain degree. This indicates that nucleation largely is controlled by the availability of nucleating material (as prescribed by the [H2SO4], availability of condensing material (in this model 15% of primary reactions of monoterpenes (MT are assumed to produce low volatile species and the properties of the size distribution (more specifically, the condensation sink. This is further demonstrated by the fact that the model captures the annual trend in nuclei mode concentration. The model is also used, alongside sensitivity tests, to examine which processes dominate the aerosol size distribution physical properties. It is shown, in agreement with previous studies, that nucleation governs the number concentration during transport from clean areas. It is also shown that primary number emissions almost exclusively govern the CN concentration when air from Central Europe is advected north over Scandinavia. We also show that biogenic emissions have a large influence on the amount of potential CCN observed

  1. New trajectory driven aerosol and chemical process model: chemical and aerosol Lagrangian model (CALM

    Directory of Open Access Journals (Sweden)

    P. Tunved

    2010-06-01

    Full Text Available A new Chemical and Aerosol Lagrangian Model (CALM have been developed and tested. The model incorporates all central aerosol dynamical processes, from nucleation, condensation, coagulation and deposition to cloud formation and in-cloud processing. The model is tested and evaluated against observations performed at the SMEAR II station located at Hyytiälä (61°51' N, 24°17' E over a time period of two years, 2000–2001. The model shows good agreement with measurements throughout most of the year, but fails in reproducing the aerosol properties during the winter season, resulting in poor agreement between model and measurements especially during December–January. Nevertheless, through the rest of the year both trends and magnitude of modal concentrations show good agreement with observation, as do the monthly average size distribution properties. The model is also shown to capture individual nucleation events to a certain degree. This indicates that nucleation largely is controlled by the availability of nucleating material (as prescribed by the [H2SO4], availability of condensing material (in this model 15% of primary reactions of monoterpenes (MT are assumed to produce low volatile species and the properties of the size distribution (more specifically, the condensation sink. This is further demonstrated by the fact that the model captures the annual trend in nuclei mode concentration. The model is also used, alongside sensitivity tests, to examine which processes dominate the aerosol size distribution physical properties. It is shown, in agreement with previous studies, that nucleation governs the number concentration while transport from clean areas takes place. It is also shown that primary number emissions almost exclusively govern the CN concentration when air from Central Europe is advected north over Scandinavia. We also show that biogenic emissions have a large influence on the amount of potential CCN observed

  2. Institute of Chemical Process Fundamentals of the ASCR: Expectation

    Czech Academy of Sciences Publication Activity Database

    Punčochář, Miroslav

    2013-01-01

    Roč. 62, 5-6 (2013), s. 214-215. ISSN 0022-9830 Institutional support: RVO:67985858 Keywords : laboratory investigation * large-scale applications * novel instrumentation and technology . Subject RIV: CI - Industrial Chemistry, Chemical Engineering

  3. Effects of irrigation efficiency on chemical transport processes

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Irrigation practices greatly affect sustainable agriculture development. In this study, we investigated the effects of irrigation efficiency on water flow and chemical transport in soils, which had significant impact on the environment. Field dye staining experiments were conducted at different soils with various irrigation amount. Image analysis was conducted to study the heterogeneous flow patterns and their relationships with the irrigation efficiency. Irrigation efficiency and its environmental effects were evaluated using various indictors, including application efficiency, deep percolation ratio, storage efficiency, and uniformity. Under the same irrigation condition, soil chemical distributions were more heterogeneous than soil water distributions. The distributions were mainly affected by soil texture, initial soil water content, and irrigation amount. Storage efficiency, irrigation uniformity, and deep percolation ratio increased with irrigation amount. Since the chemical distribution uniformity was lower than the water uniformity, the amount of chemical leaching increased sharply with decrease of irrigation uniformity, which resulted in high environmental risks of groundwater pollution.

  4. Hydrological processes and water resources management in a dryland environment III: Groundwater recharge and recession in a shallow weathered aquifer

    Directory of Open Access Journals (Sweden)

    J. A. Butterworth

    1999-01-01

    Full Text Available In crystalline basement regions of Africa, shallow weathered aquifers provide vital water resources for rural communities. To quantify evidence of the behaviour of these shallow aquifers, groundwater levels were observed at a network of 65 boreholes within the Romwe Catchment in southern Zimbabwe. Soil moisture was monitored at selected sites. Groundwater hydrographs showed considerable spatial and temporal variation. Where the soil profile was freely draining, groundwater levels typically responded within a few days of major rainstorms and large annual fluctuations in the water table of up to 7 m were recorded. In areas where a thick clay layer exists, annual fluctuations were smaller and groundwater levels rose more gradually in response to rainfall. In cultivated areas, vertical drainage was an important recharge mechanism. Groundwater hydrographs typically have an exponential recession and, by the end of the dry season in the years studied, levels were close to the base of the weathered aquifer. Variations in hydrograph response between years illustrate the importance of rainfall amount, intensity and distribution on groundwater recharge.

  5. Slaughterhouse Wastewater Treatment by Combined Chemical Coagulation and Electrocoagulation Process

    OpenAIRE

    Edris Bazrafshan; Ferdos Kord Mostafapour; Mehdi Farzadkia; Kamal Aldin Ownagh; Amir Hossein Mahvi

    2012-01-01

    Slaughterhouse wastewater contains various and high amounts of organic matter (e.g., proteins, blood, fat and lard). In order to produce an effluent suitable for stream discharge, chemical coagulation and electrocoagulation techniques have been particularly explored at the laboratory pilot scale for organic compounds removal from slaughterhouse effluent. The purpose of this work was to investigate the feasibility of treating cattle-slaughterhouse wastewater by combined chemical coagulation an...

  6. Weathering of Carbonate Rocks by Biological Soil Crusts in Karst Areas

    Institute of Scientific and Technical Information of China (English)

    Ye Chen; Bin Lian; Zuoying Yin; Yuan Tang

    2014-01-01

    The weathering of carbonate rocks by biological soil crusts (BSC) in karst areas is very common. It is helpful to understand the weathering mechanisms and processes for avoiding karst rock-desertification. The weathering of carbonate rocks by BSC in karst areas, namely the expansion, contraction and curl resulting from environmental wetting-drying cycles, was investigated and ana-lyzed in this paper. The bulk density, area and thickness of BSC were determined and the weathering amount of limestone and dolomite per unit area of BSC was calculated as 3 700 and 3 400 g·m-2; the amount of biomass on the surface of limestone and dolomite was calculated as 1 146 and 1 301 g·m-2, respectively. Such an increased weathering amount was not only the result of chemical and physical weathering of BSC on carbonate rocks, but also the attachment and cementation of BSC to clay parti-cles, dust-fall, sand particles, solid particles brought by strong air currents, wind and other factors in the surrounding environment, which may also be related to the special environment and the special time period. Based on the results obtained, a weathering mode of BSC is studied, and the mechanisms of weathering by BSC are discussed. In conclusion, we suggest that the mechanical force exerted by the expansion and constriction of gelatinous and mucilaginous substances through wetting and drying of BSC play a significant role in the physical weathering process of the carbonate substrates.

  7. Weathering of sulfides on Mars

    Science.gov (United States)

    Burns, Roger G.; Fisher, Duncan S.

    1987-01-01

    Pyrrhotite-pentlandite assemblages in mafic and ultramafic igneous rocks may have contributed significantly to the chemical weathering reactions that produce degradation products in the Martian regolith. By analogy and terrestrial processes, a model is proposed whereby supergene alteration of these primary Fe-Ni sulfides on Mars has generated secondary sulfides (e.g., pyrite) below the water table and produced acidic groundwater containing high concentrations of dissolved Fe, Ni, and sulfate ions. The low pH solutions also initiated weathering reactions of igneous feldspars and ferromagnesian silicates to form clay silicate and ferric oxyhydroxide phases. Near-surface oxidation and hydrolysis of ferric sulfato-and hydroxo-complex ions and sols formed gossan above the water table consisting of poorly crystalline hydrated ferric sulfates (e.g., jarosite), oxides (ferrihydrite, goethite), and silica (opal). Underlying groundwater, now permafrost contains hydroxo sulfato complexes of Fe, Al, Mg, Ni, which may be stabilized in frozen acidic solutions beneath the surface of Mars. Sublimation of permafrost may replenish colloidal ferric oxides, sulfates, and phyllosilicates during dust storms on Mars.

  8. Silica- and sulfate-bearing rock coatings in smelter areas: Products of chemical weathering and atmospheric pollution I. Formation and mineralogical composition

    Science.gov (United States)

    Mantha, Nathalie M.; Schindler, Michael; Murayama, Mitsuhiro; Hochella, Michael F.

    2012-05-01

    Black rock-coatings occur in proximity to smelters and roast yards of the Greater Sudbury area, Ontario, Canada and contain information about the past interactions between surface minerals, and gaseous and particulate atmospheric components, many of which were pollutants. Rock-coatings were collected from various locations within the Sudbury area and are characterized with scanning electron microscopy, transmission electron microscopy, X-ray diffraction, electron microprobe analysis, infrared spectroscopy and X-ray photoelectron spectroscopy. Acidic fumigations and rain, the result of vast quantities of SO2 released from smelting, increased the chemical weathering rate of exposed rocks in the Sudbury area. Non-stoichiometric dissolution of the silicate minerals under acidic conditions resulted in the accumulation of silicic acid and the subsequent formation of a silica-gel type coating. The silica gel transformed overtime into amorphous silica, opal (opal C and opal-CT) and cristobalite. Dissolution of the underlying rock and also of metal-bearing particles by sulfuric acid resulted in the in situ formation of metal-sulfate-rich layers on the interfaces between the atmosphere and the silica-rich coating (atmosphere-coating interface, ACI) and between the silica-rich coating and the underlying rock (rock-coating interface, RCI). These metal-sulfate-rich layers contain nanometer aggregates of Fe-Cu-sulfate-hydroxide, goldichite, mereiterite, guildite, butlerite and antlerite. The silica-rich matrix also contains a mix of detrital grains from adjacent rocks and soils (feldspar, quartz, hematite, chlorite, montmorillonite) and non-dissolved smelter-derived nano- to micro-size particulates (metal-silicates, metal-oxides, C-spheres). The apparent disequilibrium between the embedded particles and the Fe-Cu-sulfates suggests that trapped nanoparticles were encapsulated into pores which prevented their equilibration with acidic metal-sulfate-bearing fluids. An XPS depth

  9. Chemical and Biological Catalytic Enhancement of Weathering of Silicate Minerals and industrial wastes as a Novel Carbon Capture and Storage Technology

    Science.gov (United States)

    Park, A. H. A.

    2014-12-01

    Increasing concentration of CO2 in the atmosphere is attributed to rising consumption of fossil fuels around the world. The development of solutions to reduce CO2 emissions to the atmosphere is one of the most urgent needs of today's society. One of the most stable and long-term solutions for storing CO2 is via carbon mineralization, where minerals containing metal oxides of Ca or Mg are reacted with CO2 to produce thermodynamically stable Ca- and Mg-carbonates that are insoluble in water. Carbon mineralization can be carried out in-situ or ex-situ. In the case of in-situ mineralization, the degree of carbonation is thought to be limited by both mineral dissolution and carbonate precipitation reaction kinetics, and must be well understood to predict the ultimate fate of CO2 within geological reservoirs. While the kinetics of in-situ mineral trapping via carbonation is naturally slow, it can be enhanced at high temperature and high partial pressure of CO2. The addition of weak organic acids produced from food waste has also been shown to enhance mineral weathering kinetics. In the case of the ex-situ carbon mineralization, the role of these ligand-bearing organic acids can be further amplified for silicate mineral dissolution. Unfortunately, high mineral dissolution rates often lead to the formation of a silica-rich passivation layer on the surface of silicate minerals. Thus, the use of novel solvent mixture that allows chemically catalyzed removal of this passivation layer during enhanced Mg-leaching surface reaction has been proposed and demonstrated. Furthermore, an engineered biological catalyst, carbonic anhydrase, has been developed and evaluated to accelerate the hydration of CO2, which is another potentially rate-limiting step of the carbonation reaction. The development of these novel catalytic reaction schemes has significantly improved the overall efficiency and sustainability of in-situ and ex-situ mineral carbonation technologies and allowed direct

  10. Clouds, weather, climate, and modeling for K-12 and public audiences from the Center for Multi-scale Modeling of Atmospheric Processes

    Science.gov (United States)

    Foster, S. Q.; Johnson, R. M.; Randall, D. A.; Denning, A.; Russell, R. M.; Gardiner, L. S.; Hatheway, B.; Jones, B.; Burt, M. A.; Genyuk, J.

    2010-12-01

    The need for improving the representation of cloud processes in climate models has been one of the most important limitations of the reliability of climate-change simulations. Now in its fifth year, the National Science Foundation-funded Center for Multi-scale Modeling of Atmospheric Processes (CMMAP) at Colorado State University (CSU) is addressing this problem through a revolutionary new approach to representing cloud processes on their native scales, including the cloud-scale interaction processes that are active in cloud systems. CMMAP has set ambitious education and human-resource goals to share basic information about the atmosphere, clouds, weather, climate, and modeling with diverse K-12 and public audiences. This is accomplished through collaborations in resource development and dissemination between CMMAP scientists, CSU’s Little Shop of Physics (LSOP) program, and the Windows to the Universe (W2U) program at University Corporation for Atmospheric Research (UCAR). Little Shop of Physics develops new hands on science activities demonstrating basic science concepts fundamental to understanding atmospheric characteristics, weather, and climate. Videos capture demonstrations of children completing these activities which are broadcast to school districts and public television programs. CMMAP and LSOP educators and scientists partner in teaching a summer professional development workshops for teachers at CSU with a semester's worth of college-level content on the basic physics of the atmosphere, weather, climate, climate modeling, and climate change, as well as dozens of LSOP inquiry-based activities suitable for use in classrooms. The W2U project complements these efforts by developing and broadly disseminating new CMMAP-related online content pages, animations, interactives, image galleries, scientists’ biographies, and LSOP videos to K-12 and public audiences. Reaching nearly 20 million users annually, W2U is highly valued as a curriculum enhancement

  11. Hands-on, online, and workshop-based K-12 weather and climate education resources from the Center for Multi-scale Modeling of Atmospheric Processes

    Science.gov (United States)

    Foster, S. Q.; Johnson, R. M.; Randall, D. A.; Denning, A.; Burt, M. A.; Gardiner, L.; Genyuk, J.; Hatheway, B.; Jones, B.; La Grave, M. L.; Russell, R. M.

    2009-12-01

    The need for improving the representation of cloud processes in climate models has been one of the most important limitations of the reliability of climate-change simulations. Now in its fourth year, the National Science Foundation-funded Center for Multi-scale Modeling of Atmospheric Processes (CMMAP) at Colorado State University (CSU) is addressing this problem through a revolutionary new approach to representing cloud processes on their native scales, including the cloud-scale interaction processes that are active in cloud systems. CMMAP has set ambitious education and human-resource goals to share basic information about the atmosphere, clouds, weather, climate, and modeling with diverse K-12 and public audiences. This is accomplished through collaborations in resource development and dissemination between CMMAP scientists, CSU’s Little Shop of Physics (LSOP) program, and the Windows to the Universe (W2U) program at University Corporation for Atmospheric Research (UCAR). Little Shop of Physics develops new hands on science activities demonstrating basic science concepts fundamental to understanding atmospheric characteristics, weather, and climate. Videos capture demonstrations of children completing these activities which are broadcast to school districts and public television programs. CMMAP and LSOP educators and scientists partner in teaching a summer professional development workshops for teachers at CSU with a semester's worth of college-level content on the basic physics of the atmosphere, weather, climate, climate modeling, and climate change, as well as dozens of LSOP inquiry-based activities suitable for use in classrooms. The W2U project complements these efforts by developing and broadly disseminating new CMMAP-related online content pages, animations, interactives, image galleries, scientists’ biographies, and LSOP videos to K-12 and public audiences. Reaching nearly 20 million users annually, W2U is highly valued as a curriculum enhancement

  12. Survey of knowledge of hazards of chemicals potentially associated with the advanced isotope separation processes

    International Nuclear Information System (INIS)

    Hazards of chemical potentially associated with the advanced isotope separation processes are estimated based on open literature references. The tentative quantity of each chemical associated with the processes and the toxicity of the chemical are used to estimate this hazard. The chemicals thus estimated to be the most potentially hazardous to health are fluorine, nitric acid, uranium metal, uranium hexafluoride, and uranium dust. The estimated next most hazardous chemicals are bromine, hydrobromic acid, hydrochloric acid, and hydrofluoric acid. For each of these chemicals and for a number of other process-associated chemicals the following information is presented: (1) any applicable standards, recommended standards and their basis; (2) a brief discussion to toxic effects including short exposure tolerance, atmospheric concentration immediately hazardous to life, evaluation of exposures, recommended control procedures, chemical properties, and a list of any toxicology reviews; and (3) recommendations for future research

  13. Contaminants from Cretaceous Black Shale Part 1: Natural weathering processes controlling contaminant cycling in Mancos Shale, southwestern United States, with emphasis on salinity and selenium

    Science.gov (United States)

    Tuttle, Michele L.W.; Fahy, Juli W.; Elliott, John G.; Grauch, Richard I.; Stillings, Lisa L.

    2013-01-01

    Soils derived from black shale can accumulate high concentrations of elements of environmental concern, especially in regions with semiarid to arid climates. One such region is the Colorado River basin in the southwestern United States where contaminants pose a threat to agriculture, municipal water supplies, endangered aquatic species, and water-quality commitments to Mexico. Exposures of Cretaceous Mancos Shale (MS) in the upper basin are a major contributor of salinity and selenium in the Colorado River. Here, we examine the roles of geology, climate, and alluviation on contaminant cycling (emphasis on salinity and Se) during weathering of MS in a Colorado River tributary watershed. Stage I (incipient weathering) began perhaps as long ago as 20 ka when lowering of groundwater resulted in oxidation of pyrite and organic matter. This process formed gypsum and soluble organic matter that persist in the unsaturated, weathered shale today. Enrichment of Se observed in laterally persistent ferric oxide layers likely is due to selenite adsorption onto the oxides that formed during fluctuating redox conditions at the water table. Stage II weathering (pedogenesis) is marked by a significant decrease in bulk density and increase in porosity as shale disaggregates to soil. Rainfall dissolves calcite and thenardite (Na2SO4) at the surface, infiltrates to about 1 m, and precipitates gypsum during evaporation. Gypsum formation (estimated 390 kg m−2) enriches soil moisture in Na and residual SO4. Transpiration of this moisture to the surface or exposure of subsurface soil (slumping) produces more thenardite. Most Se remains in the soil as selenite adsorbed to ferric oxides, however, some oxidizes to selenate and, during wetter conditions is transported with soil moisture to depths below 3 m. Coupled with little rainfall, relatively insoluble gypsum, and the translocation of soluble Se downward, MS landscapes will be a significant nonpoint source of salinity and Se to the

  14. Flow-Injection Responses of Diffusion Processes and Chemical Reactions

    DEFF Research Database (Denmark)

    Andersen, Jens Enevold Thaulov

    2000-01-01

    manifold may be characterised by a diffusion coefficient that depends on flow rate, denoted as the kinematic diffusion coefficient. The description was applied to systems involving species of chromium, both in the case of simple diffusion and in the case of chemical reactions. It is suggested that it may...... be used in the resolution of FIA profiles to obtain information about the content of interference’s, in the study of chemical reaction kinetics and to measure absolute concentrations within the FIA-detector cell.......The technique of Flow-injection Analysis (FIA), now aged 25 years, offers unique analytical methods that are fast, reliable and consuming an absolute minimum of chemicals. These advantages together with its inherent feasibility for automation warrant the future applications of FIA as an attractive...

  15. Understanding the processes involved in weathering and experimental alteration of glassy materials. The case of some volcanic glasses from eastern Sicily (Italy)

    International Nuclear Information System (INIS)

    The objective of this thesis is to study the effects of weathering and experimental alteration in order to understand the geochemical processes involved and the variation of mineral phases in altered natural glasses. For the first time, five samples of natural volcanic glasses having different composition were collected in eastern Sicily (Italy) in order to be artificially altered and analyzed. The study of naturally altered samples has allowed to observe the effects of weathering after a period of time corresponding to the age of the sample. Moreover, the use of samples of natural glass of volcanic origin has allowed to obtain some powder or thin plates of fresh silicate glass that have been subjected to artificial alteration in the laboratory, in order to model the geochemical processes that have occurred. Alteration experiments were conducted in pure water at 90 C; samples have been altered from 1 to 1000 days of experiment. The characterization of the samples was obtained by Raman spectroscopy, which showed the effects of the devitrification and the presence of some secondary minerals such as carbonates and anatase on the obsidian thin plates, but also phillipsite and chabazite, two varieties of zeolite usually found in the cavities of oldest basalts. Solid modifications were observed by SEM. The analysis showed the formation of several secondary minerals having a composition compatible with smectites, determined by EDS spectroscopy. All these results allow to test the geochemical modeling in the long term. Further analysis will be needed to reach a full understanding of the weathering of glassy materials. (author)

  16. Flow-Injection Responses of Diffusion Processes and Chemical Reactions

    DEFF Research Database (Denmark)

    Andersen, Jens Enevold Thaulov

    2000-01-01

    The technique of Flow-injection Analysis (FIA), now aged 25 years, offers unique analytical methods that are fast, reliable and consuming an absolute minimum of chemicals. These advantages together with its inherent feasibility for automation warrant the future applications of FIA as an attractive...... tool of automated analytical chemistry. The need for an even lower consumption of chemicals and for computer analysis has motivated a study of the FIA peak itself, that is, a theoretical model was developed, that provides detailed knowledge of the FIA profile. It was shown that the flow in a FIA...

  17. Laser studies of chemical reaction and collision processes

    Energy Technology Data Exchange (ETDEWEB)

    Flynn, G. [Columbia Univ., New York, NY (United States)

    1993-12-01

    This work has concentrated on several interrelated projects in the area of laser photochemistry and photophysics which impinge on a variety of questions in combustion chemistry and general chemical kinetics. Infrared diode laser probes of the quenching of molecules with {open_quotes}chemically significant{close_quotes} amounts of energy in which the energy transferred to the quencher has, for the first time, been separated into its vibrational, rotational, and translational components. Probes of quantum state distributions and velocity profiles for atomic fragments produced in photodissociation reactions have been explored for iodine chloride.

  18. Temperature dependence of basalt weathering

    Science.gov (United States)

    Li, Gaojun; Hartmann, Jens; Derry, Louis A.; West, A. Joshua; You, Chen-Feng; Long, Xiaoyong; Zhan, Tao; Li, Laifeng; Li, Gen; Qiu, Wenhong; Li, Tao; Liu, Lianwen; Chen, Yang; Ji, Junfeng; Zhao, Liang; Chen, Jun

    2016-06-01

    The homeostatic balance of Earth's long-term carbon cycle and the equable state of Earth's climate are maintained by negative feedbacks between the levels of atmospheric CO2 and the chemical weathering rate of silicate rocks. Though clearly demonstrated by well-controlled laboratory dissolution experiments, the temperature dependence of silicate weathering rates, hypothesized to play a central role in these weathering feedbacks, has been difficult to quantify clearly in natural settings at landscape scale. By compiling data from basaltic catchments worldwide and considering only inactive volcanic fields (IVFs), here we show that the rate of CO2 consumption associated with the weathering of basaltic rocks is strongly correlated with mean annual temperature (MAT) as predicted by chemical kinetics. Relations between temperature and CO2 consumption rate for active volcanic fields (AVFs) are complicated by other factors such as eruption age, hydrothermal activity, and hydrological complexities. On the basis of this updated data compilation we are not able to distinguish whether or not there is a significant runoff control on basalt weathering rates. Nonetheless, the simple temperature control as observed in this global dataset implies that basalt weathering could be an effective mechanism for Earth to modulate long-term carbon cycle perturbations.

  19. Plants and microorganisms as drivers of mineral weathering

    Science.gov (United States)

    Dontsova, K.; Chorover, J.; Maier, R.; Hunt, E.; Zaharescu, D. G.

    2011-12-01

    Plants and microorganisms play important role in mineral weathering and soil formation modifying their environment to make it more hospitable for life. This presentation summarizes several collaborative studies that focused on understanding how interactions between plants and microorganisms, where plants provide the energy through photosynthesis, drive mineral weathering and result in soil formation. Plants influence weathering through multiple mechanisms that have been previously established, such as increase in CO2 concentration in the soil through root respiration and degradation of plant residues and exudates by heterotrophic microorganisms, release of organic acids that promote mineral dissolution, removal of weathering products from soil solution through uptake, and water redistribution. Weathering processes result in nutrient release that satisfies immediate needs of the plants and microorganisms, as well as precipitation of secondary phases, that provide surfaces for retention of nutrients and organic carbon accumulation. What makes understanding contribution of plants and microorganisms, such as bacteria and fungi, to mineral weathering challenging is the fact that they closely interact, enhancing and amplifying each other's contribution. In order to address multiple processes that contribute to and result from biological weathering a combination of chemical, biological, mineralogical, and computational techniques and methodologies is needed. This complex array of methodologies includes bulk techniques, such as determination of total dissolved organic and inorganic carbon and nitrogen, ion chromatography and high performance liquid chromatography to characterize amount and composition of exuded organic acids, inductively coupled plasma mass spectrometry to determine concentrations of lithogenic elements in solution, X-ray diffraction to characterize changes in mineral composition of the material, DNA extraction to characterize community structure, as well

  20. Model based fault diagnosis for hybrid systems : application on chemical processes

    OpenAIRE

    Olivier Maget, Nelly; Hétreux, Gilles; Le Lann, Jean-Marc

    2009-01-01

    The complexity and the size of the industrial chemical processes induce the monitoring of a growing number of process variables. Their knowledge is generally based on the measurements of system variables and on the physico-chemical models of the process. Nevertheless, this information is imprecise because of process and measurement noise. So the research ways aim at developing new and more powerful techniques for the detection of process fault. In this work, we present a method for the fault ...

  1. Geological and Mineralogical-technological features chromite ore from nickel-weathering crusts Average Bug

    Directory of Open Access Journals (Sweden)

    Perkov E.S.

    2013-09-01

    Full Text Available Conditions of occurrence and distribution features of chromites ore bodies in the ultra-basic nickel bearing weathering crusts of Middle Bug Area are considered. Main types of exogenous chromites ores in weathering crusts and beyond of them are identified as well as mineralogical, chemical and grain features of mineralization are given. Obtained data are substantiated in order to apply them while developing the efficient schemes of mining and processing of exogenous chromites ores.

  2. Treatment, Processing and Future Disposal of Radioactive Wastes at the Idaho Chemical Processing Plant

    International Nuclear Information System (INIS)

    Acidic wastes from the recovery of enriched uranium from aluminium, zirconium, and stainless-steel fuels at the Idaho Chemical Processing Plant are stored in underground tanks of two configurations and nominal sizes of 30,000 and 300,000 gallons. The design and operation of the waste-tank farm as well as the methods of environmental disposal of low-level wastes is described. The ''concentrate and contain'' philosophy of waste disposal has as its ultimate aim the production of a solid mass containing the fission products. The disadvantage of increased treatment costs may or may not be offset by reduction in storage costs. The low thermal conductivity of solids makes storage temperature considerations more important than for liquids. The acid aluminium nitrate wastes from the processing of fuels of the Material Testing Reactor type may be converted to granular alumina by calcining in a fluidized bed from 350° to 550° C. The major process components are the NaK heated calciner, an off-gas cleaning system and the solids storage vessels. The process design and the research and development programme are reviewed. On the basis of the successful demonstration of fluidized-bed calcining and high-temperature solids storage in conjunction with other considerations, a number of future storage concepts and their environmental connotations are discussed. (author)

  3. Monitoring with reflectance spectroscopy the colour change of PVC plastisol coated strip steel due to weathering

    Energy Technology Data Exchange (ETDEWEB)

    Wijdekop, M.; Arnold, J.C.; Evans, M.; John, V.; Lloyd, A.

    2005-07-15

    Weathering can cause colour changes in pigmented PVC plastisol coatings. The rate of colour change is dependent on a number of factors, such as PVC resin, pigment type and concentration, and local climate. In this paper, an investigation into the mechanisms that cause these colour changes is reported. The investigation involves a set of 350 paints, based on a typical plastisol formulation, that has been exposed to natural weathering at sites in Lancashire and Sussex in the UK, and to accelerated weathering using QUV testers with UVA-340 lamps and condensation cycles. Colour changes were measured using a Gretag SPM50 reflectance spectrophotometer. It was found that the reflectance spectra measured in this way provided a more potent tool for investigating the chemical reactions that cause discolouration in coatings during weathering than the CIE L*a*b* parameters that are normally used to describe colour changes. Reflectance spectroscopy has been shown to facilitate the correlation between natural weathering and accelerated weathering, by giving a better understanding of the prevalent chemical processes that take place in the coatings during different accelerated weathering programmes (with and without condensation) and with natural weathering at different locations (high UV climates and higher rainfall climates). Phenomena such as PVC dehydrochlorination and organic pigment degradation could be analysed conveniently using reflectance spectrophotometry. (author)

  4. Conversion of Lignocellulosic Biomass to Nanocellulose: Structure and Chemical Process

    OpenAIRE

    Lee, H. V.; S. B. A. Hamid; Zain, S. K.

    2014-01-01

    Lignocellulosic biomass is a complex biopolymer that is primary composed of cellulose, hemicellulose, and lignin. The presence of cellulose in biomass is able to depolymerise into nanodimension biomaterial, with exceptional mechanical properties for biocomposites, pharmaceutical carriers, and electronic substrate’s application. However, the entangled biomass ultrastructure consists of inherent properties, such as strong lignin layers, low cellulose accessibility to chemicals, and high cellulo...

  5. Helping Students Develop a Critical Attitude towards Chemical Process Calculations.

    Science.gov (United States)

    de Nevers, Noel; Seader, J. D.

    1992-01-01

    Discusses the use of computer-assisted programs that allow chemical engineering students to study textbook thermodynamics problems from different perspectives, including the classical graphical method, while utilizing more than one property correlation and/or operation model so that comparisons can be made and sensitivities determined more…

  6. Effects of irrigation efficiency on chemical transport processes

    Institute of Scientific and Technical Information of China (English)

    WANG Kang; ZHANG RenDuo; SHENG Feng

    2009-01-01

    Irrigation practices greatly affect sustainable agriculture development.In this study, we investigated the effects of irrigation efficiency on water flow and chemical transport in soils, which had significant impact on the environment.Field dye staining experiments were conducted at different soils with various irrigation amount.Image analysis was conducted to study the heterogeneous flow patterns and their relationships with the irrigation efficiency.Irrigation efficiency and its environmental effects were evaluated using various indictors, including application efficiency, deep percolation ratio, storage effi-ciency, and uniformity.Under the same irrigation condition, soil chemical distributions were more het-erogeneous than soil water distributions.The distributions were mainly affected by soil texture, initial soil water content, and irrigation amount.Storage efficiency, irrigation uniformity, and deep percolation ratio increased with irrigation amount.Since the chemical distribution uniformity was lower than the water uniformity, the amount of chemical leaching increased sharply with decrease of irrigation uni-formity, which resulted in high environmental risks of groundwater pollution.

  7. TREATMENT TANK CORROSION STUDIES FOR THE ENHANCED CHEMICAL CLEANING PROCESS

    Energy Technology Data Exchange (ETDEWEB)

    Wiersma, B.

    2011-08-24

    Radioactive waste is stored in high level waste tanks on the Savannah River Site (SRS). Savannah River Remediation (SRR) is aggressively seeking to close the non-compliant Type I and II waste tanks. The removal of sludge (i.e., metal oxide) heels from the tank is the final stage in the waste removal process. The Enhanced Chemical Cleaning (ECC) process is being developed and investigated by SRR to aid in Savannah River Site (SRS) High-Level Waste (HLW) as an option for sludge heel removal. Corrosion rate data for carbon steel exposed to the ECC treatment tank environment was obtained to evaluate the degree of corrosion that occurs. These tests were also designed to determine the effect of various environmental variables such as temperature, agitation and sludge slurry type on the corrosion behavior of carbon steel. Coupon tests were performed to estimate the corrosion rate during the ECC process, as well as determine any susceptibility to localized corrosion. Electrochemical studies were performed to develop a better understanding of the corrosion mechanism. The tests were performed in 1 wt.% and 2.5 wt.% oxalic acid with HM and PUREX sludge simulants. The following results and conclusions were made based on this testing: (1) In 1 wt.% oxalic acid with a sludge simulant, carbon steel corroded at a rate of less than 25 mpy within the temperature and agitation levels of the test. No susceptibility to localized corrosion was observed. (2) In 2.5 wt.% oxalic acid with a sludge simulant, the carbon steel corrosion rates ranged between 15 and 88 mpy. The most severe corrosion was observed at 75 C in the HM/2.5 wt.% oxalic acid simulant. Pitting and general corrosion increased with the agitation level at this condition. No pitting and lower general corrosion rates were observed with the PUREX/2.5 wt.% oxalic acid simulant. The electrochemical and coupon tests both indicated that carbon steel is more susceptible to localized corrosion in the HM/oxalic acid environment than

  8. New insights into chemical processes within martian high latitude soils

    Science.gov (United States)

    Horgan, B.; Bell, J. F.

    2010-12-01

    Our analysis of near-infrared spectra of low albedo soils in the northern lowlands of Mars has revealed that they can be classified into three compositional groups: (1) relatively unaltered and high-calcium pyroxene-rich, (2) pervasively leached and glass-rich, and (3) gypsum-rich. Here we present results from spectral and morphologic studies, which together show that the diversity of soils observed from orbit and those observed in situ by the Phoenix lander can largely be explained by aqueous processes acting on high-calcium pyroxene-rich soils. Soils in Acidalia Planitia, parts of the north polar sand sea, and certain units within the north polar plateau exhibit spectral signatures consistent with an enrichment in iron-bearing glass, as well as signatures consistent with leached glass rinds, which form during acidic alteration of glass surfaces. As glass enrichment can be produced during acidic leaching of basaltic sand, we have proposed that these soils are the endproducts of widespread and pervasive acidic leaching. If these altered sands originally had a composition similar to the relatively unaltered high-calcium pyroxene-rich soils observed elsewhere in the northern lowlands, then we should also expect them to contain calcium-bearing secondary precipitates, primarily gypsum. While spectral analysis of Acidalia-type soils places an approximate upper limit on their gypsum concentration of 15-20 wt.%, our results suggest that the gypsum-rich (up to 40 wt.%) sands in the Olympia Undae region of the north polar sand sea could also be sourced from Acidalia-type materials within the north polar plateau. Although Olympia Undae gypsum concentrations appear too high to justify this hypothesis, our morphologic studies of the region suggest that the high concentrations are most likely surficial and do not represent the volumetric concentrations. By mapping the distribution of tensional surface cracks on sand dunes in HiRISE images, we have shown that the strength of

  9. Development of Chemical Process Design and Control for Sustainability

    Science.gov (United States)

    This contribution describes a novel process systems engineering framework that couples advanced control with sustainability evaluation and decision making for the optimization of process operations to minimize environmental impacts associated with products, materials, and energy....

  10. Chemical Cleaning Process for Porable Water Distrubution Pipe Systems

    OpenAIRE

    ECT Team, Purdue

    2007-01-01

    Aging potable water distribution pipe systems are becoming a major concern throughout the world. Deterioration of water quality and service as a result of micro biological tuberculation and corrosion continues to increase. Major costs for replacement or rehabilitation of distribution systems are being faced by most communities. The chemical cleaning solution is an organic oxide scavenger which is mixed with a predetermined quantity of muriatic acid and circulated through an isolated section o...

  11. Chemical process for backsurging fluid through well casing perforations

    Energy Technology Data Exchange (ETDEWEB)

    Berkshire, D.C.; Richardson, E.A.; Scheuerman, R.F.

    1980-08-26

    A backsurge of fluid through perforations in a well casing is chemically induced by injecting into the surrounding reservoir a solution which contains (A) nitrogen gas-generating reactants, (B) a reaction-retarding alkaline buffer, and (C) a ph-reducing reactant that is capable of subsequently overriding the buffer, so that a rapid production of gas and heat causes a backsurging of fluid into the wellbore.

  12. Chemical process for backsurging fluid through well casing perforations

    Energy Technology Data Exchange (ETDEWEB)

    Berkshire, D.C.; Richardson, E.A.; Scheuerman, R.F.

    1981-09-15

    A backsurge of fluid through perforations in a well casing is chemically induced by injecting into the surrounding reservoir a solution which contains nitrogen gas-generating reactants, a reaction-retarding alkaline buffer, and a pH-reducing reactant that is capable of subsequently overriding the buffer, so that a rapid production of gas and heat causes a backsurging of fluid into the wellbore.

  13. Emissions model of waste treatment operations at the Idaho Chemical Processing Plant

    International Nuclear Information System (INIS)

    An integrated model of the waste treatment systems at the Idaho Chemical Processing Plant (ICPP) was developed using a commercially-available process simulation software (ASPEN Plus) to calculate atmospheric emissions of hazardous chemicals for use in an application for an environmental permit to operate (PTO). The processes covered by the model are the Process Equipment Waste evaporator, High Level Liquid Waste evaporator, New Waste Calcining Facility and Liquid Effluent Treatment and Disposal facility. The processes are described along with the model and its assumptions. The model calculates emissions of NOx, CO, volatile acids, hazardous metals, and organic chemicals. Some calculated relative emissions are summarized and insights on building simulations are discussed

  14. Rock-weathering by lichens in Antarctic:patterns and mechanisms

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Saxicolous species of lichens are able to induce and accelerate weathering of their rocksubstrate, and effects of lichens on substrate can be attributed to both physical and chemical causes.This paper is focused on biotic weathering actions of epilithic and endolithic species on the differentrock types (sandstones and volcanogenic rocks) in Antarctica. The patterns, mechanisms, processes andneoformations of rock-weathering resulting from lichen colonization are expounded in detail.Furthermore, it is pointed out that, for a better understanding of the impacts of lichens onenvironments, the studies on the rate of biotic weathering and the comprehensive involvement of thelichen effects on weathering of natural rocks remain to be carried out in Antarctica.

  15. Salt Weathering on Mars

    Science.gov (United States)

    Jagoutz, E.

    2006-12-01

    Large well rounded boulders and angular rock fragments characterizes the Martian landscape as seen on the recent excellent quality photos. Analyzing the different rock-shapes indicates a time sequence of emplacement, fragmentation and transport of different rocks on Mars, which might give interesting insight into transport and weathering processes. Larger commonly well rounded boulders were emplaced onto gravel plains. After emplacement, these rocks were fragmented and disassembled. Nests of angular rock fragments are marking the locations of preexisting larger rocks. Frequently it is possible to reconstruct larger rounded rocks from smaller angular fragments. In other cases transport after fragmentation obscured the relationship of the fragments. However, a strewn field of fragments is still reminiscent of the preexisting rock. Mechanical salt weathering could be a plausible explanation for the insitu fragmentation of larger rounded blocks into angular fragments. Impact or secondary air fall induced fragmentation produces very different patterns, as observed around impact crates on Earth. Salt weathering of rocks is a common process in terrestrial environments. Salt crystallization in capillaries causes fragmentation of rocks, irrespective of the process of salt transportation and concentration. On Earth significant salt weathering can be observed in different climatic environments: in the transition zone of alluvial aprons and salt playas in desserts and in dry valleys of Antarctica. In terrestrial semi-arid areas the salt is transported by salt solution, which is progressively concentrated by evaporation. In Antarctic dry valleys freeze-thaw cycles causes salt transportation and crystallization resulting in rock fragmentation. This salt induced process can lead to complete destruction of rocks and converts rocks to fine sand. The efficient breakdown of rocks is dominating the landscape in some dry valleys of the Earth but possibly also on Mars. (Malin, 1974

  16. Using a Readily Available Commercial Spreadsheet to Teach a Graduate Course on Chemical Process Simulation

    Science.gov (United States)

    Clarke, Matthew A.; Giraldo, Carlos

    2009-01-01

    Chemical process simulation is one of the most fundamental skills that is expected from chemical engineers, yet relatively few graduates have the opportunity to learn, in depth, how a process simulator works, from programming the unit operations to the sequencing. The University of Calgary offers a "hands-on" postgraduate course in Chemical…

  17. 29 CFR 1910.119 - Process safety management of highly hazardous chemicals.

    Science.gov (United States)

    2010-07-01

    ...: Material Safety Data Sheets meeting the requirements of 29 CFR 1910.1200(g) may be used to comply with this... 29 Labor 5 2010-07-01 2010-07-01 false Process safety management of highly hazardous chemicals... § 1910.119 Process safety management of highly hazardous chemicals. Purpose. This section...

  18. Rapid Neutron Capture Process in Supernovae and Chemical Element Formation

    Indian Academy of Sciences (India)

    Rulee Baruah; Kalpana Duorah; H. L. Duorah

    2009-09-01

    The rapid neutron capture process (r-process) is one of the major nucleosynthesis processes responsible for the synthesis of heavy nuclei beyond iron. Isotopes beyond Fe are most exclusively formed in neutron capture processes and more heavier ones are produced by the r-process. Approximately half of the heavy elements with mass number ≻ 70 and all of the actinides in the solar system are believed to have been produced in the r-process. We have studied the r-process in supernovae for the production of heavy elements beyond = 40 with the newest mass values available. The supernova envelopes at a temperature ≻ 109 K and neutron density of 1024 cm-3 are considered to be one of the most potential sites for the r-process. The primary goal of the r-process calculations is to fit the global abundance curve for solar system r-process isotopes by varying time dependent parameters such as temperature and neutron density. This method aims at comparing the calculated abundances of the stable isotopes with observation.We have studied the r-process path corresponding to temperatures ranging from 1.0 × 109 K to 3.0 × 109 K and neutron density ranging from 1020 cm-3 to 1030 cm-3. With temperature and density conditions of 3.0 × 109 K and 1020 cm-3 a nucleus of mass 273 was theoretically found corresponding to atomic number 115. The elements obtained along the r-process path are compared with the observed data at all the above temperature and density range.

  19. New Vistas in Chemical Product and Process Design

    DEFF Research Database (Denmark)

    Zhang, Lei; Babi, Deenesh Kavi; Gani, Rafiqul

    2016-01-01

    , its corresponding process, and its integration are highlighted. Although significant advances have been made in the development of systematic model-based techniques for process design (also for optimization, operation, and control), much work is needed to reach the same level for product design....... Timeline diagrams illustrating key contributions in product design, process design, and integrated product-process design are presented. The search for novel, innovative, and sustainable solutions must be matched by consideration of issues related to the multidisciplinary nature of problems, the lack of...

  20. Hydrophobic hydration processes. Thermal and chemical denaturation of proteins

    OpenAIRE

    Fisicaro, E.; Compari, C.; Braibanti, A.

    2011-01-01

    Abstract The hydrophobic hydration processes have been analysed under the light of a mixture model of water that is assumed to be composed by clusters (W5)I, clusters (W4)II and free water molecules WIII. The hydrophobic hydration processes can be subdivided into two Classes A and B. In the processes of Class A, the transformation A(? ?wWI? ?wWII+ ?wWIII+ cavity) takes place, with expulsion from the bulk of ?w water molecules WIII, whereas in the processes of Class B the opposite t...

  1. Monthly Weather Review

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Supplements to the Monthly Weather Review publication. The Weather Bureau published the Monthly weather review Supplement irregularly from 1914 to 1949. The...

  2. Winter Weather Checklists

    Science.gov (United States)

    ... Health Matters What's New Preparation & Planning Disasters & Severe Weather Earthquakes Extreme Heat Floods Hurricanes Landslides Tornadoes Tsunamis ... Weather Information on Specific Types of Emergencies Winter Weather Checklists Language: English Español (Spanish) Recommend on Facebook ...

  3. Defense Waste Processing Facility Simulant Chemical Processing Cell Studies for Sludge Batch 9

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Tara E. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Newell, J. David [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Woodham, Wesley H. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-08-10

    The Savannah River National Laboratory (SRNL) received a technical task request from Defense Waste Processing Facility (DWPF) and Saltstone Engineering to perform simulant tests to support the qualification of Sludge Batch 9 (SB9) and to develop the flowsheet for SB9 in the DWPF. These efforts pertained to the DWPF Chemical Process Cell (CPC). CPC experiments were performed using SB9 simulant (SB9A) to qualify SB9 for sludge-only and coupled processing using the nitric-formic flowsheet in the DWPF. Two simulant batches were prepared, one representing SB8 Tank 40H and another representing SB9 Tank 51H. The simulant used for SB9 qualification testing was prepared by blending the SB8 Tank 40H and SB9 Tank 51H simulants. The blended simulant is referred to as SB9A. Eleven CPC experiments were run with an acid stoichiometry ranging between 105% and 145% of the Koopman minimum acid equation (KMA), which is equivalent to 109.7% and 151.5% of the Hsu minimum acid factor. Three runs were performed in the 1L laboratory scale setup, whereas the remainder were in the 4L laboratory scale setup. Sludge Receipt and Adjustment Tank (SRAT) and Slurry Mix Evaporator (SME) cycles were performed on nine of the eleven. The other two were SRAT cycles only. One coupled flowsheet and one extended run were performed for SRAT and SME processing. Samples of the condensate, sludge, and off-gas were taken to monitor the chemistry of the CPC experiments.

  4. Cogeneration handbook for the chemical process industries. [Contains glossary

    Energy Technology Data Exchange (ETDEWEB)

    Fassbender, A.G.; Fassbender, L.L.; Garrett-Price, B.A.; Moore, N.L.; Eakin, D.E.; Gorges, H.A.

    1984-03-01

    The desision of whether to cogenerate involves several considerations, including technical, economic, environmental, legal, and regulatory issues. Each of these issues is addressed separately in this handbook. In addition, a chapter is included on preparing a three-phase work statement, which is needed to guide the design of a cogeneration system. In addition, an annotated bibliography and a glossary of terminology are provided. Appendix A provides an energy-use profile of the chemical industry. Appendices B through O provide specific information that will be called out in subsequent chapters.

  5. Sustainable Chemical Process Development through an Integrated Framework

    DEFF Research Database (Denmark)

    Papadakis, Emmanouil; Kumar Tula, Anjan; Anantpinijwatna, Amata;

    2016-01-01

    This paper describes the development and the application of a general integrated framework based on systematic model-based methods and computer-aided tools with the objective to achieve more sustainable process designs and to improve the process understanding. The developed framework can be appli...... case studies involve multiphase reaction systems for the synthesis of active pharmaceutical ingredients....

  6. Chemical Changes in Proteins Produced by Thermal Processing.

    Science.gov (United States)

    Dutson, T. R.; Orcutt, M. W.

    1984-01-01

    Discusses effects of thermal processing on proteins, focusing on (1) the Maillard reaction; (2) heat denaturation of proteins; (3) aggregation, precipitation, gelation, and degradation; and (4) other thermally induced protein reactions. Also discusses effects of thermal processing on muscle foods, egg proteins, fruits and vegetables, and cereal…

  7. The linkage between uranium, iron and carbon cycling. Processes at interfaces: evidences from combined solution chemical and spectroscopic studies

    International Nuclear Information System (INIS)

    Interfacial processes have a critical role in many reactions and phenomena in the environment, including mineral weathering, particle stability in surface waters, transport of chemical species and element cycling in natural environments. In order to predict the environmental impact of human activities such as uranium mining and radioactive waste disposal, it is necessary to understand the migration of actinides, uranium among them, in the environment. Iron oxides and oxyhydroxides are ubiquitous in nature and they are of particular interest due to their large capacity to sorb radionuclides onto their surface. The Fe and U cycles are also linked to the carbon one and aqueous carbonate plays a major role in the transport of radionuclides due to its high affinity to form complexes with hexavalent uranium. On the other hand, dissolved carbonate can compete for the sorption sites of the iron oxides, promoting the dissolution of these oxides and consequently increasing the mobility of the associated radionuclides in natural systems. Our understanding of how radionuclides impact the environment is dependent on our ability to measure chemical reactions at environmental interfaces. (orig.)

  8. Using Drawing Technology to Assess Students' Visualizations of Chemical Reaction Processes

    Science.gov (United States)

    Chang, Hsin-Yi; Quintana, Chris; Krajcik, Joseph

    2014-06-01

    In this study, we investigated how students used a drawing tool to visualize their ideas of chemical reaction processes. We interviewed 30 students using thinking-aloud and retrospective methods and provided them with a drawing tool. We identified four types of connections the students made as they used the tool: drawing on existing knowledge, incorporating dynamic aspects of chemical processes, linking a visualization to the associated chemical phenomenon, and connecting between the visualization and chemistry concepts. We also compared students who were able to create dynamic visualizations with those who only created static visualizations. The results indicated a relationship between students constructing a dynamic view of chemical reaction processes and their understanding of chemical reactions. This study provides insights into the use of visualizations to support instruction and assessment to facilitate students' integrated understanding of chemical reactions.

  9. Biorefineries to integrate fuel, energy and chemical production processes

    Directory of Open Access Journals (Sweden)

    Enrica Bargiacchi

    2007-12-01

    Full Text Available The world of renewable energies is in fast evolution and arouses political and public interests, especially as an opportunity to boost environmental sustainability by mitigation of greenhouse gas emissions. This work aims at examining the possibilities related to the development of biorefineries, where biomass conversion processes to produce biofuels, electricity and biochemicals are integrated. Particular interest is given to the production processes of biodiesel, bioethanol and biogas, for which present world situation, problems, and perspectives are drawn. Potential areas for agronomic and biotech researches are also discussed. Producing biomass for biorefinery processing will eventually lead to maximize yields, in the non food agriculture.

  10. Alternative Processes for Water Reclamation and Solid Waste Processing in a Physical/chemical Bioregenerative Life Support System

    Science.gov (United States)

    Rogers, Tom D.

    1990-01-01

    Viewgraphs on alternative processes for water reclamation and solid waste processing in a physical/chemical-bioregenerative life support system are presented. The main objective is to focus attention on emerging influences of secondary factors (i.e., waste composition, type and level of chemical contaminants, and effects of microorganisms, primarily bacteria) and to constructively address these issues by discussing approaches which attack them in a direct manner.

  11. Automated Weather Observing System

    Data.gov (United States)

    Department of Transportation — The Automated Weather Observing System (AWOS) is a suite of sensors, which measure, collect, and disseminate weather data to help meteorologists, pilots, and flight...

  12. Assessing the value of post-processed state-of-the-art long-term weather forecast ensembles for agricultural water management mediated by farmers' behaviours

    Science.gov (United States)

    Li, Yu; Giuliani, Matteo; Castelletti, Andrea

    2016-04-01

    Recent advances in modelling of coupled ocean-atmosphere dynamics significantly improved skills of long-term climate forecast from global circulation models (GCMs). These more accurate weather predictions are supposed to be a valuable support to farmers in optimizing farming operations (e.g. crop choice, cropping and watering time) and for more effectively coping with the adverse impacts of climate variability. Yet, assessing how actually valuable this information can be to a farmer is not straightforward and farmers' response must be taken into consideration. Indeed, in the context of agricultural systems potentially useful forecast information should alter stakeholders' expectation, modify their decisions, and ultimately produce an impact on their performance. Nevertheless, long-term forecast are mostly evaluated in terms of accuracy (i.e., forecast quality) by comparing hindcast and observed values and only few studies investigated the operational value of forecast looking at the gain of utility within the decision-making context, e.g. by considering the derivative of forecast information, such as simulated crop yields or simulated soil moisture, which are essential to farmers' decision-making process. In this study, we contribute a step further in the assessment of the operational value of long-term weather forecasts products by embedding these latter into farmers' behavioral models. This allows a more critical assessment of the forecast value mediated by the end-users' perspective, including farmers' risk attitudes and behavioral patterns. Specifically, we evaluate the operational value of thirteen state-of-the-art long-range forecast products against climatology forecast and empirical prediction (i.e. past year climate and historical average) within an integrated agronomic modeling framework embedding an implicit model of the farmers' decision-making process. Raw ensemble datasets are bias-corrected and downscaled using a stochastic weather generator, in

  13. Various types of polyurethanes in the process of Chemical Recycling

    OpenAIRE

    Beckmann, Silke; Herzog, Michael

    2015-01-01

    Increasing raw material costs and more stringent regulations have led to more pressure to develop customer-oriented recycling processes for polyurethanes. Furthermore, waste disposal runs into increasing costs for the producers while old methods of disposal are prohibited legally, both in the US and Europe. One way to solve this problem is to develop a well-suited process and plant for a customer specialised procedure to re-use the waste material obtained for each type of polyurethane product...

  14. Chemical and physicochemical characteristics changes during passion fruit juice processing

    OpenAIRE

    Aline Gurgel Fernandes; Gerusa Matias dos Santos; Daniele Sales da Silva; Paulo Henrique Machado de Sousa; Geraldo Arraes Maia; Raimundo Wilane de Figueiredo

    2011-01-01

    Passion fruit is widely consumed due to its pleasant flavour and aroma acidity, and it is considered very important a source of minerals and vitamins. It is used in many products such as ice-cream, mousses and, especially, juices. However, the processing of passion fruit juice may modify the composition and biodisponibility of the bioactive compounds. Investigations of the effects of processing on nutritional components in tropical juices are scarce. Frequently, only losses of vitamin C are e...

  15. Numerical Simulation of Rheological, Chemical and Hydromechanical Processes of Thrombolysis

    Science.gov (United States)

    Khramchenkov, E.; Khramchenkov, M.

    2015-04-01

    Mathematical model of clot lysis in blood vessels is developed on the basis of equations of convection-diffusion. Fibrin of the clot is considered stationary solid phase, and plasminogen, plasmin and plasminogen-activators - as dissolved fluid phases. As a result of numerical solution of the model predictions of lysis process are gained. Important influence of clot swelling on the process of lysis is revealed.

  16. Isotope separation by chemical exchange process: Final technical report

    International Nuclear Information System (INIS)

    The feasibility of a chemical exchange method for the separation of the isotopes of europium was demonstrated in the system EuCl2-EuCl3. The single stage separation factor, α, in this system is 1.001 or 1.0005 per mass unit. This value of α is comparable to the separation factors reported for the U4+ - U6 and U3+ - Y4+ systems. The separation of the ionic species was done by precipitation of the Eu2+ ions or by extraction of the Eu3+ ions with HDEHP. Conceptual schemes were developed for a countercurrent reflux cascades consisting of solvent extraction contractors. A regenerative electrocel, combining simultaneous europium reduction, europium oxidation with energy generation, and europium stripping from the organic phase is described. 32 refs., 22 figs., 6 tabs

  17. Some topics on geochemistry of weathering: a review

    Directory of Open Access Journals (Sweden)

    Milton L.L. Formoso

    2006-12-01

    Full Text Available Weathering is a complex process comprising physical disaggregation, chemical and biological decomposition of rocks and minerals transforming complex structure minerals in simpler ones. Hydrolysis of silicates is perhaps the most important process but associated certainly to biological weathering. It is discussed the role ofwaters: activities/concentrations of chemical species, pH, Eh, importance of complexes. Weathering is not only a destructive process. It can concentrate chemical species and form mineral deposits (kaolin, bauxite, Fe, Mn, P, Nb, Au. Weathering studies are important in pedology, engineering geology, hydrogeology, paleoclimatology and ecology. The use of stonemeal is based upon the study of rock weathering.Intemperismo é um processo complexo compreendendo desagregação física, decomposição química e biológica de rochas e minerais transformando minerais de estrutura complexa em estruturas mais simples. Hidrólise de silicates é talvez o mais importante mas certamente associado ao intemperismo biológico. É discutido o papel da água: atividades/concentrações de espécies químicas, pH, Eh, importância dos complexos. Intemperismo não é somente um processo destrutivo. O intemperismo pode concentrar espécies químicas e formar depósitos minerais (caolim, bauxita, Fe, Mn, P, Nb, Au. Estudos de intemperismo são importantes em pedologia, geologia de engenharia, hidrogeologia, paleoclimatologia e ecologia. O uso de rochagem é baseado em estudo de intemperismo de rocha.

  18. Cave breakdown by vadose weathering.

    OpenAIRE

    Osborne R. Armstrong L.

    2002-01-01

    Vadose weathering is a significant mechanism for initiating breakdown in caves. Vadose weathering of ore bodies, mineral veins, palaeokarst deposits, non-carbonate keystones and impure, altered or fractured bedrock, which is intersected by caves, will frequently result in breakdown. Breakdown is an active, ongoing process. Breakdown occurs throughout the vadose zone, and is not restricted to large diameter passages, or to cave ceilings. The surfaces of disarticulated blocks are commonly coate...

  19. NASA's Advancements in Space-Based Spectrometry Lead to Improvements in Weather Prediction and Understanding of Climate Processes

    Science.gov (United States)

    Susskind, Joel; Iredell, Lena

    2010-01-01

    AIRS (Atmospheric Infra-Red Sounder), was launched, in conjunction with AMSU-A (Advanced Microwave Sounding Unit-A) on the NASA polar orbiting research satellite EOS (Earth Observing System) Aqua satellite in May 2002 as a next generation atmospheric sounding system. Atmospheric sounders provide information primarily about the vertical distribution of atmospheric temperature and water vapor distribution. This is achieved by measuring outgoing radiation in discrete channels (spectral intervals) which are sensitive primarily to variations of these geophysical parameters. The primary objectives of AIRS/AMSU were to utilize such information in order to improve the skill of numerical weather prediction as well as to measure climate variability and trends. AIRS is a multi-detector array grating spectrometer with 2378 channels covering the spectral range 650/cm (15 microns) to 2660/cm (3.6 microns) with a resolving power (i/a i) of roughly 1200 where a i is the spectral channel bandpass. Atmospheric temperature profile can be determined from channel observations taken within the 15 micron (the long-wave CO2 absorption band) and within the 4.2 micron (the short-wave CO2 absorption band). Radiances in these (and all other) spectral intervals in the infrared are also sensitive to the presence of clouds in the instrument?s field of view (FOV), which are present about 95% of the time. AIRS was designed so as to allow for the ability to produce accurate Quality Controlled atmospheric soundings under most cloud conditions. This was achieved by having 1) extremely low channel noise values in the shortwave portion of the spectrum and 2) a very flat spatial response function within a channel?s FOV. IASI, the high spectral resolution IR interferometer flying on the European METOP satellite, does not contain either of these important characteristics. The AIRS instrument was also designed to be extremely stabile with regard to its spectral radiometric characteristics, which is

  20. Magnesium isotope fractionation between brucite [Mg(OH)2] and Mg aqueous species: Implications for silicate weathering and biogeochemical processes

    Science.gov (United States)

    Li, Weiqiang; Beard, Brian L.; Li, Chengxiang; Johnson, Clark M.

    2014-05-01

    Brucite, with its octahedral structure, has a lattice configuration that is similar to the Mg-bearing octahedral layers in phyllosilicates. Understanding stable Mg isotope fractionation between brucite and aqueous solution therefore bears on interpretation of Mg isotope data in natural weathering systems. In this study, we experimentally determined Mg isotope fractionation between brucite and two Mg aqueous species, the free Mg aquo ion ([Mg(OH2)6]2+) and EDTA-bonded Mg (Mg-EDTA2-). Results from recrystallization and brucite synthesis experiments suggest mild preferential partitioning of light Mg isotopes into brucite compared to Mg aquo ions at low temperatures, where measured ΔMgbrucite-Mg26 fractionation increased from ca. -0.3‰ at 7 °C, to ca. -0.2‰ at 22 °C, to ca. 0‰ at 40 °C. MgO hydrolysis experiments in EDTA-bearing solutions suggest that the ΔMgbrucite-Mg-EDTA26 fractionation is ⩾+2.0‰ at 22 °C, indicating that light Mg isotopes strongly partition into Mg-EDTA complex relative to brucite, as well as relative to Mg aquo ions. Magnesium atoms in brucite, Mg aquo ions, and Mg-EDTA complexes are all octahedrally coordinated, and the measured Mg isotope fractionations correlate with average bond lengths for Mg. Aqueous Mg ions have the shortest bond length among the three phases, and enrich heavy Mg isotopes relative to brucite and Mg-EDTA. In contrast, Mg-EDTA has the longest average bond length for Mg, and enriches light Mg isotopes relative to Mg aquo ions and brucite; the relatively long Mg-EDTA bond suggests that organically bound Mg may commonly have low 26Mg/24Mg ratios, which may explain proposed "vital" effects for stable Mg isotopes. Such relations between bond length and Mg isotope fractionation could be extended to other phyllosilicates such as serpentine- and clay-group minerals where Mg is also octahedrally coordinated.

  1. Fatty acid methyl esters production: chemical process variables

    Directory of Open Access Journals (Sweden)

    Paulo César Narváez Rincón

    2010-06-01

    Full Text Available The advantages of fatty acid methyl esters as basic oleochemicals over fatty acids, the seventies world energy crisis and the use of those oleochemicals as fuels, have increased research interest on fats and oils trans-esterification. In this document, a review about basic aspects, uses, process variables and problems associated to the production process of fatty acid methyl esters is presented. A global view of recent researches, most of them focused in finding a new catalyst with same activity as the alcohol-soluble hydroxides (NaOH, KOH, and suitable to be used in transforming fats and oils with high levels of free fatty acids and water avoiding separation problems and reducing process costs, is also discussed.

  2. Process-oriented knowledge-sharing platform for chemical engineering design projects

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A process-oriented knowledge-sharing platform is studied to improve knowledge sharing and project management of chemical engineering design enterprises. First, problems and characteristics of knowledge sharing in multi-projects of chemical engineering design are analyzed. Then based on theories of project management, process management, and knowledge management, a process-oriented knowledge-sharing platform is proposed. The platform has three characteristics: knowledge is divided into professional knowledge...

  3. Chemical process control : present status and future needs ; the view from European industry

    OpenAIRE

    Schuler, Hans; Allgöwer, Frank; Gilles, Ernst Dieter

    1991-01-01

    Not only in Europe, chemical process control is characterized by a broad invasion of distributed control systems into chemical plants. The information integration from process control up to business management is a great challenge of today which follows from the overall computerization of production. Most of the recent progress in process automation results from the application of computer science paradigms to control systems, and of advanced developments in field instrumentation. Despite the...

  4. Processes for converting biomass-derived feedstocks to chemicals and liquid fuels

    Energy Technology Data Exchange (ETDEWEB)

    Held, Andrew; Woods, Elizabeth; Cortright, Randy; Gray, Matthew

    2016-07-05

    The present invention provides processes, methods, and systems for converting biomass-derived feedstocks to liquid fuels and chemicals. The method generally includes the reaction of a hydrolysate from a biomass deconstruction process with hydrogen and a catalyst to produce a reaction product comprising one of more oxygenated compounds. The process also includes reacting the reaction product with a condensation catalyst to produce C.sub.4+ compounds useful as fuels and chemicals.

  5. Nonequilibrium thermodynamics transport and rate processes in physical, chemical and biological systems

    CERN Document Server

    Demirel, Yasar

    2014-01-01

    Natural phenomena consist of simultaneously occurring transport processes and chemical reactions. These processes may interact with each other and may lead to self-organized structures, fluctuations, instabilities, and evolutionary systems. Nonequilibrium Thermodynamics, 3rd edition emphasizes the unifying role of thermodynamics in analyzing the natural phenomena. This third edition updates and expands on the first and second editions by focusing on the general balance equations for coupled processes of physical, chemical, and biological systems. The new edition contains a new chapte

  6. Chemical Processing Department monthly report for April 1958

    Energy Technology Data Exchange (ETDEWEB)

    Warren, J.H.

    1958-05-21

    The separations plants operated on schedule, and Pu production exceeded commitment. UO{sub 3} production and shipments were also ahead of schedule. Purex operation under pseudo two-cycle conditions (elimination of HS and 1A columns, co-decontamination cycle concentrator HCP) was successful. Final U stream was 3{times} lower in Pu than ever before; {gamma} activity in recovered HNO{sub 3} was also low. Four of 6 special E metal batches were processed through Redox and analyzed. Boric acid is removed from solvent extraction process via aq waste. The filter in Task II hydrofluorinator was changed from carbon to Poroloy. Various modifications to equipment were made.

  7. Thermo-Chemical Modelling Strategies for the Pultrusion Process

    DEFF Research Database (Denmark)

    Baran, Ismet; Hattel, Jesper Henri; Tutum, Cem Celal

    2013-01-01

    -DG solver. It is found that the steady state approach is much faster than the transient approach in terms of the computational time and the number of iteration loops to obtain converged results for reaching the steady state. Hence, it is highly suitable for automatic process optimization which often...

  8. Influence of process parameters on the surface and chemical properties of activated carbon obtained from biochar by chemical activation.

    Science.gov (United States)

    Angın, Dilek; Altintig, Esra; Köse, Tijen Ennil

    2013-11-01

    Activated carbons were produced from biochar obtained through pyrolysis of safflower seed press cake by chemical activation with zinc chloride. The influences of process variables such as the activation temperature and the impregnation ratio on textural and chemical-surface properties of the activated carbons were investigated. Also, the adsorptive properties of activated carbons were tested using methylene blue dye as the targeted adsorbate. The experimental data indicated that the adsorption isotherms are well described by the Langmuir equilibrium isotherm equation. The optimum conditions resulted in activated carbon with a monolayer adsorption capacity of 128.21 mg g(-1) and carbon content 76.29%, while the BET surface area and total pore volume corresponded to 801.5m(2)g(-1) and 0.393 cm(3)g(-1), respectively. This study demonstrated that high surface area activated carbons can be prepared from the chemical activation of biochar with zinc chloride as activating agents. PMID:24080293

  9. Chemical, microbiological and physical processes in polluted groundwater

    International Nuclear Information System (INIS)

    Inorganic and organic pollutants issuing from solid waste deposits cause a groundwater deterioration which depends in its nature and extent on the distance between the base of waste material and the groundwater surface, the quality and quantity of the leachates, the nature of groundwater and its flow velocity and the nature of the aquifer. The contaminants are diluted or decontaminated by biogeochemical, geochemical and physical effects as the groundwater flows downstream. The self-purification processes may be summarized by biogeochemical degradation, precipitation and co-precipitation, sorption at soil particles, at bacterial slimes and at colloidal hydroxides, ion exchange, mechanical filtration and gas exchange. The effect of dilution may be treated with help of the concept of hydrodynamic dispersion. A discussion of the relative importance of self-purification processes and dilution may use anomalous distribution of stable isotopes in the polluted groundwater. (author)

  10. Study the Migration Process of Chemical Substances through the Packaging/Food Interface during Microwave Treatment

    Directory of Open Access Journals (Sweden)

    Fang Duan

    2013-01-01

    Full Text Available The diffusion of chemical substances from packaging into food endangers people’s health. The migration amount of the chemical substances increases with the time and temperature, but the diffusion process for different kinds of packaging materials differs much. Most recently, the research community showed a renewed interest on the diffusion process of chemical substances through packaging/food interface during microwave treatment. In this study, the diffusion coefficient model is suggested and then the migration process is studied based on Fick’s diffusion law. The results are finally compared with the experimental data, showing good agreement.

  11. Leaching properties and chemical compositions of calcines produced at the Idaho Chemical Processing Plant

    International Nuclear Information System (INIS)

    No significant chemical differences were determined between retrieved and fresh calcine based on chemical and spectrochemical analyses. Little can be derived from the amounts of the radioisotopes present in the retrieved calcine samples other than the ratios of strontium-90 to cesium-137 are typical of aged fission product. The variations in concentrations of radionuclides within the composite samples of each bin also reflect the differences in compositions of waste solutions calcined. In general the leaching characteristics of both calcines by distilled water are similar. In both materials the radionuclides of cesium and strontium were selectively leached at significant rates, although cesium leached much more completely from the alumina calcine than from the zirconia calcine. Cesium and strontium are probably contained in both calcines as nitrate salts and also as fluoride salts in zirconia calcine, all of which are at least slightly soluble in water. Radionuclides of cerium, ruthenium, and plutonium in both calcines were highly resistant to leaching and leached at rates similar to or less than those of the matrix elements. These elements exist as polyvalent metal ions in the waste solutions before calcination and they probably form insoluble oxides and fluorides in the calcine. The relatively slow leaching of nitrate ion from zirconia calcine and radiocesium from both calcines suggests that the calcine matrix in some manner prevents complete or immediate contact of the soluble ions with water. Whether radiostrontium forms slightly fluoride salts or forms nitrate salts which are protected in the same manner as radiocesium is unknown. Nevertheless, selective leaching of cesium and strontim is retarded in some manner by the calcine matrix

  12. Security risk assessment and protection in the chemical and process industry

    OpenAIRE

    Reniers, Genserik; van Lerberghe, Paul; Van Gulijk, Coen

    2014-01-01

    This article describes a security risk assessment and protection methodology that was developed for use in the chemical- and process industry in Belgium. The approach of the method follows a risk-based approach that follows desing principles for chemical safety. That approach is beneficial for workers in the chemical industry because they recognize the steps in this model from familiar safety models .The model combines the rings-of-protection approach with generic security practices including...

  13. Fun with Weather

    Science.gov (United States)

    Yildirim, Rana

    2007-01-01

    This three-part weather-themed lesson for young learners connects weather, clothing, and feelings vocabulary. The target structures covered are: asking about the weather; comparing weather; using the modal auxiliary, should; and the question word, when. The lessons utilize all four skills and include such activities as going outside, singing,…

  14. Essentials of water systems design in the oil, gas, and chemical processing industries

    CERN Document Server

    Bahadori, Alireza; Boyd, Bill

    2013-01-01

    Essentials of Water Systems Design in the Oil, Gas and Chemical Processing Industries provides valuable insight for decision makers by outlining key technical considerations and requirements of four critical systems in industrial processing plants—water treatment systems, raw water and plant water systems, cooling water distribution and return systems, and fire water distribution and storage facilities. The authors identify the key technical issues and minimum requirements related to the process design and selection of various water supply systems used in the oil, gas, and chemical processing industries. This book is an ideal, multidisciplinary work for mechanical engineers, environmental scientists, and oil and gas process engineers.

  15. Swimming Pool Water Treatment Chemicals and/or Processes. Standard No. 22.

    Science.gov (United States)

    National Sanitation Foundation, Ann Arbor, MI.

    Chemicals or processes used or intended for use, in the treatment of swimming pool water are covered. Minimum public health limits or acceptability in regard to toxicity, biocidal effectiveness, and chemical behavior and analysis are presented. The appendices give guidelines to the scientific and statistically sound evaluations to determine the…

  16. Chemical precipitation processes for the treatment of low and medium level liquid waste

    International Nuclear Information System (INIS)

    Chemical precipitation processes for the treatment of various radioactive low and medium level liquid waste are described. Application to waste from reprocessing plants, removal of the main gamma emitters, actinide separation, utility liquid wastes generated during pwr operation, and combination of ultrafiltration with chemical precipitation, are all discussed. (U.K.)

  17. The Technology for Intensification of Chemical Reaction Process Envisaged in the "863" Plan

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    @@ It is learned from the Ministry of Science and Technology that in order to promote the shift of China's chemical industry toward an energy efficient and environmentally friendly product mode, the technology for intensification of chemical reaction processes has been included in the National "863" Project of the "Eleventh Five-Year Plan", and the application for research project proposals is to be accepted.

  18. Evaluating exposures to complex mixtures of chemicals during a new production process in the plastics industry

    NARCIS (Netherlands)

    Meijster, T.; Burstyn, I.; Wendel de Joode, B. van; Posthumus, M.A.; Kromhout, H.

    2004-01-01

    The goal of this study was to monitor emission of chemicals at a factory where plastics products were fabricated by a new robotic (impregnated tape winding) production process. Stationary and personal air measurements were taken to determine which chemicals were released and at what concentrations.

  19. Benzene as a Chemical Hazard in Processed Foods

    Directory of Open Access Journals (Sweden)

    Vânia Paula Salviano dos Santos

    2015-01-01

    Full Text Available This paper presents a literature review on benzene in foods, including toxicological aspects, occurrence, formation mechanisms, and mitigation measures and analyzes data reporting benzene levels in foods. Benzene is recognized by the IARC (International Agency for Research on Cancer as carcinogenic to humans, and its presence in foods has been attributed to various potential sources: packaging, storage environment, contaminated drinking water, cooking processes, irradiation processes, and degradation of food preservatives such as benzoates. Since there are no specific limits for benzene levels in beverages and food in general studies have adopted references for drinking water in a range from 1–10 ppb. The presence of benzene has been reported in various food/beverage substances with soft drinks often reported in the literature. Although the analyses reported low levels of benzene in most of the samples studied, some exceeded permissible limits. The available data on dietary exposure to benzene is minimal from the viewpoint of public health. Often benzene levels were low as to be considered negligible and not a consumer health risk, but there is still a need of more studies for a better understanding of their effects on human health through the ingestion of contaminated food.

  20. Green process for chemical functionalization of nanocellulose with carboxylic acids.

    Science.gov (United States)

    Espino-Pérez, Etzael; Domenek, Sandra; Belgacem, Naceur; Sillard, Cécile; Bras, Julien

    2014-12-01

    An environmentally friendly and simple method, named SolReact, has been developed for a solvent-free esterification of cellulose nanocrystals (CNC) surface by using two nontoxic carboxylic acids (CA), phenylacetic acid and hydrocinnamic acid. In this process, the carboxylic acids do not only act as grafting agent, but also as solvent media above their melting point. Key is the in situ solvent exchange by water evaporation driving the esterification reaction without drying the CNC. Atomic force microscopy and X-ray diffraction analyses showed no significant change in the CNC dimensions and crystallinity index after this green process. The presence of the grafted carboxylic was characterized by analysis of the "bulk" CNC with elemental analysis, infrared spectroscopy, and (13)C NMR. The ability to tune the surface properties of grafted nanocrystals (CNC-g-CA) was evaluated by X-ray photoelectron spectroscopy analysis. The hydrophobicity behavior of the functionalized CNC was studied through the water contact-angle measurements and vapor adsorption. The functionalization of these bionanoparticles may offer applications in composite manufacturing, where these nanoparticles have limited dispersibility in hydrophobic polymer matrices and as nanoadsorbers due to the presence of phenolic groups attached on the surface. PMID:25353612

  1. Aluminium nitride coatings preparation using a chemical vapour deposition process

    Energy Technology Data Exchange (ETDEWEB)

    Armas, B.; Combescure, C.; Icaza Herrera, M. de; Sibieude, F. [Centre National de la Recherche Scientifique (CNRS), 66 - Font-Romeu (France). Inst. de Science et du Genie des Materiaux et des Procedes

    2000-07-01

    Aluminium nitride was obtained in a cold wall reactor using AlCl{sub 3} and NH{sub 3} as precursors and N{sub 2} as a carrier gas. AlCl{sub 3} was synthesized << in situ >> by means of an original method based on the reaction of SiCl{sub 4(g)} with Al{sub (S)}. The substrate used was a cylinder of graphite coated with SiC and heated by high frequency induction. The deposition rate was studied as a function of temperature in the range 900 - 1500 C, the total pressure varying from 2 to 180 hPa. At low temperatures an Arrhenius type representation of the kinetics for several pressures indicated a thermally activated process with an apparent activation energy of about 80 kJ.mol{sup -1}. At high deposition temperatures, the deposition rate was almost constant, indicating that the growth was controlled by a diffusion process. The influence of gas composition and total AlCl{sub 3} flow rate was also discussed. The different layers were characterised particularly by means of X-ray diffraction and SEM. The influence of temperature and total pressure on crystallization and morphology was studied. (orig.)

  2. SLUDGE BATCH 6/TANK 40 SIMULANT CHEMICAL PROCESS CELL SIMULATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Koopman, David

    2010-04-28

    Phase III simulant flowsheet testing was completed using the latest composition estimates for SB6/Tank 40 feed to DWPF. The goals of the testing were to determine reasonable operating conditions and assumptions for the startup of SB6 processing in the DWPF. Testing covered the region from 102-159% of the current DWPF stoichiometric acid equation. Nitrite ion concentration was reduced to 90 mg/kg in the SRAT product of the lowest acid run. The 159% acid run reached 60% of the DWPF Sludge Receipt and Adjustment Tank (SRAT) limit of 0.65 lb H2/hr, and then sporadically exceeded the DWPF Slurry Mix Evaporator (SME) limit of 0.223 lb H2/hr. Hydrogen generation rates peaked at 112% of the SME limit, but higher than targeted wt% total solids levels may have been partially responsible for rates seen. A stoichiometric factor of 120% met both objectives. A processing window for SB6 exists from 102% to something close to 159% based on the simulant results. An initial recommendation for SB6 processing is at 115-120% of the current DWPF stoichiometric acid equation. The addition of simulated Actinide Removal Process (ARP) and Modular Caustic Side Solvent Extraction Unit (MCU) streams to the SRAT cycle had no apparent impact on the preferred stoichiometric factor. Hydrogen generation occurred continuously after acid addition in three of the four tests. The three runs at 120%, 118.4% with ARP/MCU, and 159% stoichiometry were all still producing around 0.1 lb hydrogen/hr at DWPF scale after 36 hours of boiling in the SRAT. The 120% acid run reached 23% of the SRAT limit and 37% of the SME limit. Conversely, nitrous oxide generation was subdued compared to previous sludge batches, staying below 29 lb/hr in all four tests or about a fourth as much as in comparable SB4 testing. Two processing issues, identified during SB6 Phase II flowsheet testing and qualification simulant testing, were monitored during Phase III. Mercury material balance closure was impacted by acid stoichiometry

  3. Chemical Processing Department monthly report for May 1960

    Energy Technology Data Exchange (ETDEWEB)

    1960-06-20

    Production of Pu nitrate from separations plants during May was below forecast. A Np recovery campaign in Purex yielded 1.5 kg. Production and shipments of UO{sub 3} met schedules. Unfabricated Pu metal production was below forecast, but all shipments were on schedule. Decontamination efficiency was low in Purex solvent extraction around the time of the Np recovery. The damaged Redox B-2 dissolver is being restored; processing of enriched metal in A and C dissolvers was continued. A spectrograph for inclusions in Pu metal was installed. 4 kg Pu oxide was produced in a continuous direct calciner. Scope design on Purex Np recovery and purification facilities was completed. Other design and contracts are discussed.

  4. Study on the chemical treatment processes of the uranium pyrochlore of Araxa

    International Nuclear Information System (INIS)

    Several processes are presented for the chemical treatment, in laboratory scale, of the uranium pyrochlore concentrates found in Araxa (Minas Gerais, Brazil), aiming to the extraction of uranium, thorium and rare earths, besides the recovery of niobium pentoxide

  5. Arsenopyrite weathering under conditions of simulated calcareous soil.

    Science.gov (United States)

    Lara, René H; Velázquez, Leticia J; Vazquez-Arenas, Jorge; Mallet, Martine; Dossot, Manuel; Labastida, Israel; Sosa-Rodríguez, Fabiola S; Espinosa-Cristóbal, León F; Escobedo-Bretado, Miguel A; Cruz, Roel

    2016-02-01

    Mining activities release arsenopyrite into calcareous soils where it undergoes weathering generating toxic compounds. The research evaluates the environmental impacts of these processes under semi-alkaline carbonated conditions. Electrochemical (cyclic voltammetry, chronoamperometry, EIS), spectroscopic (Raman, XPS), and microscopic (SEM, AFM, TEM) techniques are combined along with chemical analyses of leachates collected from simulated arsenopyrite weathering to comprehensively examine the interfacial mechanisms. Early oxidation stages enhance mineral reactivity through the formation of surface sulfur phases (e.g., S n (2-)/S(0)) with semiconductor properties, leading to oscillatory mineral reactivity. Subsequent steps entail the generation of intermediate siderite (FeCO3)-like, followed by the formation of low-compact mass sub-micro ferric oxyhydroxides (α, γ-FeOOH) with adsorbed arsenic (mainly As(III), and lower amounts of As(V)). In addition, weathering reactions can be influenced by accessible arsenic resulting in the formation of a symplesite (Fe3(AsO4)3)-like compound which is dependent on the amount of accessible arsenic in the system. It is proposed that arsenic release occurs via diffusion across secondary α, γ-FeOOH structures during arsenopyrite weathering. We suggest weathering mechanisms of arsenopyrite in calcareous soil and environmental implications based on experimental data. PMID:26498805

  6. SLUDGE BATCH 6/TANK 51 SIMULANT CHEMICAL PROCESS CELL SIMULATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Koopman, David; Best, David

    2010-04-28

    Qualification simulant testing was completed to determine appropriate processing conditions and assumptions for the Sludge Batch 6 (SB6) Shielded Cells demonstration of the DWPF flowsheet using the qualification sample from Tank 51 for SB6 after SRNL washing. It was found that an acid addition window of 105-139% of the DWPF acid equation (100-133% of the Koopman minimum acid equation) gave acceptable Sludge Receipt and Adjustment Tank (SRAT) and Slurry Mix Evaporator (SME) results for nitrite destruction and hydrogen generation. Hydrogen generation occurred continuously after acid addition in three of the four tests. The three runs at 117%, 133%, and 150% stoichiometry (Koopman) were all still producing around 0.1 lb hydrogen/hr at DWPF scale after 42 hours of boiling in the SRAT. The 150% acid run reached 110% of the DWPF SRAT limit of 0.65 lb H{sub 2}/hr, and the 133% acid run reached 75% of the DWPF SME limit of 0.223 lb H{sub 2}/hr. Conversely, nitrous oxide generation was subdued compared to previous sludge batches, staying below 25 lb/hr in all four tests or about a fourth as much as in comparable SB4 testing. Two other processing issues were noted. First, incomplete mercury suspension impacted mercury stripping from the SRAT slurry. This led to higher SRAT product mercury concentrations than targeted (>0.45 wt% in the total solids). Associated with this issue was a general difficulty in quantifying the mass of mercury in the SRAT vessel as a function of time, especially as acid stoichiometry increased. About ten times more mercury was found after drying the 150% acid SME product to powder than was indicated by the SME product sample results. Significantly more mercury was also found in the 133% acid SME product samples than was found during the SRAT cycle sampling. It appears that mercury is segregating from the bulk slurry in the SRAT vessel, as mercury amalgam deposits for example, and is not being resuspended by the agitators. The second processing issue

  7. Nonequilibrium process in the $\\sigma$ model and chemical relaxation time in a homogeneous pionic gas

    OpenAIRE

    Ishii, Mitsuru

    1996-01-01

    In a homogeneous pionic gas system, chemical nonequilibrium process is considered to understand its effect in the expansion processes that are realized immediately after heavy ion collisions. The chemical relaxation time is calculated by incorporating the $\\pi+\\pi \\leftrightarrow \\pi+\\pi+\\pi+\\pi$ reaction, which is given in the second order of perturbation in the $\\sigma$ model. The $\\pi+\\pi \\leftrightarrow \\pi+\\pi+\\pi+\\pi$ reaction is assumed to be less frequent than the $\\pi+\\pi \\leftrighta...

  8. Solar-Enhanced Advanced Oxidation Processes for Water Treatment: Simultaneous Removal of Pathogens and Chemical Pollutants

    OpenAIRE

    Oyuna Tsydenova; Valeriy Batoev; Agniya Batoeva

    2015-01-01

    The review explores the feasibility of simultaneous removal of pathogens and chemical pollutants by solar-enhanced advanced oxidation processes (AOPs). The AOPs are based on in-situ generation of reactive oxygen species (ROS), most notably hydroxyl radicals •OH, that are capable of destroying both pollutant molecules and pathogen cells. The review presents evidence of simultaneous removal of pathogens and chemical pollutants by photocatalytic processes, namely TiO2 photocatalysis and photo-Fe...

  9. Enhanced Productivity of Chemical Processes Using Dense Fluidized Beds

    Energy Technology Data Exchange (ETDEWEB)

    Sibashis Banerjee; Alvin Chen; Rutton Patel; Dale Snider; Ken Williams; Timothy O' Hern; Paul Tortora

    2008-02-29

    The work detailed in this report addresses Enabling Technologies within Computational Technology by integrating a “breakthrough” particle-fluid computational technology into traditional Process Science and Engineering Technology. The work completed under this DOE project addresses five major development areas 1) gas chemistry in dense fluidized beds 2) thermal cracking of liquid film on solids producing gas products 3) liquid injection in a fluidized bed with particle-to-particle liquid film transport 4) solid-gas chemistry and 5) first level validation of models. Because of the nature of the research using tightly coupled solids and fluid phases with a Lagrangian description of the solids and continuum description of fluid, the work provides ground-breaking advances in reactor prediction capability. This capability has been tested against experimental data where available. The commercial product arising out of this work is called Barracuda and is suitable for a wide (dense-to-dilute) range of industrial scale gas-solid flows with and without reactions. Commercial applications include dense gas-solid beds, gasifiers, riser reactors and cyclones.

  10. Landslides as weathering reactors; links between physical erosion and weathering in rapidly eroding mountain belts

    Science.gov (United States)

    Emberson, R.; Hovius, N.; Galy, A.

    2014-12-01

    The link between physical erosion and chemical weathering is generally modelled with a surface-blanketing weathering zone, where the supply of fresh minerals is tied to the average rate of denudation. In very fast eroding environments, however, sediment production is dominated by landsliding, which acts in a stochastic fashion across the landscape, contrasting strongly with more uniform denudation models. If physical erosion is a driver of weathering at the highest erosion rates, then an alternative weathering model is required. Here we show that landslides can be effective 'weathering reactors'. Previous work modelling the effect of landslides on chemical weathering (Gabet 2007) considered the fresh bedrock surfaces exposed in landslide scars. However, fracturing during the landslide motion generates fresh surfaces, the total surface area of which exceeds that of the exposed scar by many orders of magnitude. Moreover, landslides introduce concavity into hillslopes, which acts to catch precipitation. This is funnelled into a deposit of highly fragmented rock mass with large reactive surface area and limited hydraulic conductivity (Lo et al. 2007). This allows percolating water reaction time for chemical weathering; any admixture of macerated organic debris could yield organic acid to further accelerate weathering. In the South island of New Zealand, seepage from recent landslide deposits has systematically high solute concentrations, far outstripping concentration in runoff from locations where soils are present. River total dissolved load in the western Southern Alps is highly correlated with the rate of recent (<35yrs) landsliding, suggesting that landslides are the dominant locus of weathering in this rapidly eroding landscape. A tight link between landsliding and weathering implies that localized weathering migrates through the landscape with physical erosion; this contrasts with persistent and ubiquitous weathering associated with soil production. Solute

  11. The Main Plasma Chemical Process of Nitric Oxide Production by Arc Discharge

    Science.gov (United States)

    Yang, Qi; Hu, Hui; Chen, Weipeng; Xu, Jie; Zhang, Jinli; Wu, Shuang

    2011-12-01

    By adopting the optical multi-channel analyzer combined with fourier transform infrared (FTIR) spectrometer, the dominant free radicals and products generated by arc discharge were measured and studied, and the main plasma chemical reaction process in the nitric oxide production by arc discharge was identified. Plasma chemical kinetic curves of O, O2, N2, N and NO were simulated by using CHEMKIN and MATLAB. The results show that the main plasma chemical reaction process of nitric oxide production by arc discharge is a replacement reaction between O and N2, where NO can be generated instantaneously when discharging reaches stable.

  12. The Main Plasma Chemical Process of Nitric Oxide Production by Arc Discharge

    International Nuclear Information System (INIS)

    By adopting the optical multi-channel analyzer combined with fourier transform infrared (FTIR) spectrometer, the dominant free radicals and products generated by arc discharge were measured and studied, and the main plasma chemical reaction process in the nitric oxide production by arc discharge was identified. Plasma chemical kinetic curves of O, O2, N2, N and NO were simulated by using CHEMKIN and MATLAB. The results show that the main plasma chemical reaction process of nitric oxide production by arc discharge is a replacement reaction between O and N2, where NO can be generated instantaneously when discharging reaches stable. (15th asian conference on electrical discharge)

  13. Continuous-Flow Processes in Heterogeneously Catalyzed Transformations of Biomass Derivatives into Fuels and Chemicals

    Directory of Open Access Journals (Sweden)

    Antonio A. Romero

    2012-07-01

    Full Text Available Continuous flow chemical processes offer several advantages as compared to batch chemistries. These are particularly relevant in the case of heterogeneously catalyzed transformations of biomass-derived platform molecules into valuable chemicals and fuels. This work is aimed to provide an overview of key continuous flow processes developed to date dealing with a series of transformations of platform chemicals including alcohols, furanics, organic acids and polyols using a wide range of heterogeneous catalysts based on supported metals, solid acids and bifunctional (metal + acidic materials.

  14. A theoretical consideration on uranium isotope effects observed in chemical uranium-235 enrichment processes

    International Nuclear Information System (INIS)

    Theoretical consideration on the uranium isotope effects in chemical chromatographic uranium isotope enrichment processes are presented, making use of up-to-date spectroscopic, solution chemical and separation factor data. It is shown that hydration of the uranyl (UO22+) and uranous (U4+) ions has a profound effect on the reduced partition function ratios (RPFR's) of these ions and that, in accordance with experiment, the RPFR of the uranous ion is larger than that of the uranyl ion. Future prospects concerning the separation factors in chemical processes are mentioned. (orig.)

  15. Integration of chemical product development, process design and operation based on a kilo-plant

    Institute of Scientific and Technical Information of China (English)

    QIAN Yu; WU Zhihui; JIANG Yanbin

    2006-01-01

    Presented in this paper is an integrated approach of computer-aided product development, process design and operation analysis based on a kilo-plant. The implemented kilo-plant, as a research platform to manufacture product in kilogram-scale, was designed especially for fine and specialty chemicals. The characteristics of product synthesis, process operation and product quality control are investigated coupled with computer-aided monitoring, online modeling, simulation and operation process optimization. In this way, chemical product discovery, process design and operation are integrated in a systematic approach, in the aim to respond to rapid changing marketplace demands to new products.

  16. In-can melting demonstration of wastes from the Idaho Chemical Processing Plant

    International Nuclear Information System (INIS)

    The immobilization of Idaho Chemical Processing Plant (ICPP) zirconia calcine using Idaho glass composition (ICPP-127) was evaluated at Pacific Northwest Laboratory (PNL) in two engineering-scale in-can melter tests. The glass was initially characterized in the laboratory to verify processing parameters. Glass was then produced in a pilot-scale melter and then in a full-scale melter to evaluate the processing and the resultant product. Potential corrosion problems were identified with the glass and some processing problems were encountered, but neither is insurmountable. The product is a durable leach-resistant glass. The glass appears to be nonhomogeneous, but chemically it is quite uniform

  17. Disentangling oil weathering using GC x GC. 1. chromatogram analysis.

    Science.gov (United States)

    Arey, J Samuel; Nelson, Robert K; Reddy, Christopher M

    2007-08-15

    Historically, the thousands of compounds found in oils constituted an "unresolved complex mixture" that frustrated efforts to analyze oil weathering. Moreover, different weathering processes inflict rich and diverse signatures of compositional change in oil, and conventional methods do not effectively decode this elaborate record. Using comprehensive two-dimensional gas chromatography (GC x GC), we can separate thousands of hydrocarbon components and simultaneously estimate their chemical properties. We investigated 13 weathered field samples collected from the Bouchard 120 heavy fuel oil spill in Buzzards Bay, Massachusetts in 2003. We first mapped hydrocarbon vapor pressures and aqueous solubilities onto the compositional space explored by GC x GC chromatograms of weathered samples. Then we developed methods to quantitatively decouple mass loss patterns associated with evaporation and dissolution. The compositional complexity of oil, traditionally considered an obstacle, was now an advantage. We exploited the large inventory of chemical information encoded in oil to robustly differentiate signatures of mass transfer to air and water. With this new approach, we can evaluate mass transfer models (the Part 2 companion to this paper) and more properly account for evaporation, dissolution, and degradation of oil in the environment. PMID:17874781

  18. Weather service upgrade too costly?

    Science.gov (United States)

    Bush, Susan

    America needs timely and accurate weather forecasting, said Ernest F. Hollings (D-S.C.), chairman of the Senate Committee on Commerce, Science, and Transportation on National Ocean Policy. Calling the existing warning and forecast system dangerously obsolete, Hollings said that new technology “should dramatically improve the accuracy and timeliness of weather predictions,” as we face the new challenge of bringing the National Weather Service into the 21st century. Hollings' committee heard testimony to consider the modernization of the NWS and pending legislation (S98, S916) on June 18.Major components of the Weather Service Modernization program, according to John A. Knauss, administrator of the National Oceanic and Atmospheric Administration, are the Next Generation Weather Radar (NEXRAD), a new generation of Geostationary Operational Environmental Satellites (GOES-NEXT), the Automated Surface Observing System (ASOS), and the Advanced Weather Interactive Processing System (AWIA). The best defense against severe weather—early warnings—is probably hampered by outdated equipment, he added.

  19. Material compatibility and corrosion control of the KWU chemical cleaning process

    International Nuclear Information System (INIS)

    The concentrations of salt impurities within the deposits on the tube sheet and in the tube to tube-support-plate crevices can induce a variety of corrosion mechanisms on steam generator tubes. One of the most effective ways of counteracting corrosion mechanisms and thus of improving steam generator performance is to clean the steam generators and keep them in a clean condition. As shown by field results chemical cleaning is a way of removing hazardous deposits from steam generators. All available chemical cleaning processes use inhibitors to control the corrosion except the KWU chemical cleaning process. In this article the corrosion control technique of KWU Chemical Cleaning Process without using conventional inhibitors will be explained and the state of the field experience with respect to material compatibility will be presented. (author). 4 figs., 1 tab., 8 refs

  20. Down Select Report of Chemical Hydrogen Storage Materials, Catalysts, and Spent Fuel Regeneration Processes

    International Nuclear Information System (INIS)

    The DOE Hydrogen Storage Program is focused on identifying and developing viable hydrogen storage systems for onboard vehicular applications. The program funds exploratory research directed at identifying new materials and concepts for storage of hydrogen having high gravimetric and volumetric capacities that have the potential to meet long term technical targets for onboard storage. Approaches currently being examined are reversible metal hydride storage materials, reversible hydrogen sorption systems, and chemical hydrogen storage systems. The latter approach concerns materials that release hydrogen in endothermic or exothermic chemical bond-breaking processes. To regenerate the spent fuels arising from hydrogen release from such materials, chemical processes must be employed. These chemical regeneration processes are envisioned to occur offboard the vehicle

  1. Down Select Report of Chemical Hydrogen Storage Materials, Catalysts, and Spent Fuel Regeneration Processes

    Energy Technology Data Exchange (ETDEWEB)

    Ott, Kevin; Linehan, Sue; Lipiecki, Frank; Aardahl, Christopher L.

    2008-08-24

    The DOE Hydrogen Storage Program is focused on identifying and developing viable hydrogen storage systems for onboard vehicular applications. The program funds exploratory research directed at identifying new materials and concepts for storage of hydrogen having high gravimetric and volumetric capacities that have the potential to meet long term technical targets for onboard storage. Approaches currently being examined are reversible metal hydride storage materials, reversible hydrogen sorption systems, and chemical hydrogen storage systems. The latter approach concerns materials that release hydrogen in endothermic or exothermic chemical bond-breaking processes. To regenerate the spent fuels arising from hydrogen release from such materials, chemical processes must be employed. These chemical regeneration processes are envisioned to occur offboard the vehicle.

  2. A systems engineering approach to manage the complexity in sustainable chemical product-process design

    DEFF Research Database (Denmark)

    Gani, Rafiqul

    This paper provides a perspective on model-data based solution approaches for chemical product-process design, which consists of finding the identity of the candidate chemical product, designing the process that can sustainably manufacture it and verifying the performance of the product during...... application. The chemical product tree is potentially very large and a wide range of options exist for selecting the product to make, the raw material to use as well as the processing route to employ. It is shown that systematic computer-aided methods and tools integrated within a model-data based design...... framework can manage the complexity associated with product-process problems very efficiently. Three specific computer-aided tools (ICAS, Sustain-Pro and VPPDLab) have been presented and their applications to product-process design, highlighted....

  3. Thermo-chemical process with sewage sludge by using CO2.

    Science.gov (United States)

    Kwon, Eilhann E; Yi, Haakrho; Kwon, Hyun-Han

    2013-10-15

    This work proposed a novel methodology for energy recovery from sewage sludge via the thermo-chemical process. The impact of CO2 co-feed on the thermo-chemical process (pyrolysis and gasification) of sewage sludge was mainly investigated to enhance thermal efficiency and to modify the end products from the pyrolysis and gasification process. The CO2 injected into the pyrolysis and gasification process enhance the generation of CO. As compared to the thermo-chemical process in an inert atmosphere (i.e., N2), the generation of CO in the presence of CO2 was enhanced approximately 200% at the temperature regime from 600 to 900 °C. The introduction of CO2 into the pyrolysis and gasification process enabled the condensable hydrocarbons (tar) to be reduced considerably by expediting thermal cracking (i.e., approximately 30-40%); thus, exploiting CO2 as chemical feedstock and/or reaction medium for the pyrolysis and gasification process leads to higher thermal efficiency, which leads to environmental benefits. This work also showed that sewage sludge could be a very strong candidate for energy recovery and a raw material for chemical feedstock. PMID:23792821

  4. Enhanced Weather Radar (EWxR) System

    Science.gov (United States)

    Kronfeld, Kevin M. (Technical Monitor)

    2003-01-01

    An airborne weather radar system, the Enhanced Weather Radar (EWxR), with enhanced on-board weather radar data processing was developed and tested. The system features additional weather data that is uplinked from ground-based sources, specialized data processing, and limited automatic radar control to search for hazardous weather. National Weather Service (NWS) ground-based Next Generation Radar (NEXRAD) information is used by the EWxR system to augment the on-board weather radar information. The system will simultaneously display NEXRAD and on-board weather radar information in a split-view format. The on-board weather radar includes an automated or hands-free storm-finding feature that optimizes the radar returns by automatically adjusting the tilt and range settings for the current altitude above the terrain and searches for storm cells near the atmospheric 0-degree isotherm. A rule-based decision aid was developed to automatically characterize cells as hazardous, possibly-hazardous, or non-hazardous based upon attributes of that cell. Cell attributes are determined based on data from the on-board radar and from ground-based radars. A flight path impact prediction algorithm was developed to help pilots to avoid hazardous weather along their flight plan and their mission. During development the system was tested on the NASA B757 aircraft and final tests were conducted on the Rockwell Collins Sabreliner.

  5. Orbital forcing of glacial/interglacial variations in chemical weathering and silicon cycling within the upper White Nile basin, East Africa: Stable-isotope and biomarker evidence from Lakes Victoria and Edward

    Science.gov (United States)

    Cockerton, Helen E.; Street-Perrott, F. Alayne; Barker, Philip A.; Leng, Melanie J.; Sloane, Hilary J.; Ficken, Katherine J.

    2015-12-01

    On Quaternary time scales, the global biogeochemical cycle of silicon is interlocked with the carbon cycle through biotic enhancement of silicate weathering and uptake of dissolved silica by vascular plants and aquatic microalgae (notably diatoms, for which Si is an essential nutrient). Large tropical river systems dominate the export of Si from the continents to the oceans. Here, we investigate variations in Si cycling in the upper White Nile basin over the last 15 ka, using sediment cores from Lakes Victoria and Edward. Coupled measurements of stable O and Si isotopes on diatom separates were used to reconstruct past changes in lake hydrology and Si cycling, while the abundances of lipid biomarkers characteristic of terrestrial/emergent higher plants, submerged/floating aquatic macrophytes and freshwater algae document past ecosystem changes. During the late-glacial to mid-Holocene, 15-5.5 ka BP, orbital forcing greatly enhanced monsoon rainfall, forest cover and chemical weathering. Riverine inputs of dissolved silica from the lake catchments exceeded aquatic demand and may also have had lower Si-isotope values. Since 5.5 ka BP, increasingly dry climates and more open vegetation, reinforced by the spread of agricultural cropland over the last 3-4 ka, have reduced dissolved silica inputs into the lakes. Centennial-to millennial-scale dry episodes are also evident in the isotopic records and merit further investigation.

  6. A systematic synthesis and design methodology to achieve process intensification in (bio) chemical processes

    DEFF Research Database (Denmark)

    Lutze, Philip; Román-Martinez, Alicia; Woodley, John; Gani, Rafiqul

    Process intensification (PI) has the potential to improve existing processes or create new process options which are needed in order to produce products using more sustainable methods. PI creates an enormous number of process options. In order to manage the complexity of options in which a feasible...... and optimal process solution may exist, the application of process synthesis tools results in the development of a systematic methodology to implement PI. Starting from an analysis of existing processes, this methodology generates a set of feasible process options and reduces their number through a...

  7. Technology Roadmap: Energy and GHG reductions in the chemical industry via catalytic processes

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2013-06-01

    The chemical industry is a large energy user; but chemical products and technologies also are used in a wide array of energy saving and/or renewable energy applications so the industry has also an energy saving role. The chemical and petrochemical sector is by far the largest industrial energy user, accounting for roughly 10% of total worldwide final energy demand and 7% of global GHG emissions. The International Council of Chemical Associations (ICCA) has partnered with the IEA and DECHEMA (Society for Chemical Engineering and Biotechnology) to describe the path toward further improvements in energy efficiency and GHG reductions in the chemical sector. The roadmap looks at measures needed from the chemical industry, policymakers, investors and academia to press on with catalysis technology and unleash its potential around the globe. The report uncovers findings and best practice opportunities that illustrate how continuous improvements and breakthrough technology options can cut energy use and bring down greenhouse gas (GHG) emission rates. Around 90% of chemical processes involve the use of catalysts – such as added substances that increase the rate of reaction without being consumed by it – and related processes to enhance production efficiency and reduce energy use, thereby curtailing GHG emission levels. This work shows an energy savings potential approaching 13 exajoules (EJ) by 2050 – equivalent to the current annual primary energy use of Germany.

  8. Basalt weathering in an Arctic Mars-analog site

    Science.gov (United States)

    Yesavage, Tiffany; Thompson, Aaron; Hausrath, Elisabeth M.; Brantley, Susan L.

    2015-07-01

    The martian surface has undergone chemical and physical weathering in the past, and these processes may continue intermittently today. To explore whether martian rocks are likely to retain features indicative of weathering, we investigated how basaltic material weathers on Earth. Specifically, we investigated weathering of a Quaternary-aged basaltic flow at the Sverrefjell volcano in Svalbard, above the Arctic Circle. This flow weathered since deglaciation under cold, dry (characterized the mineralogical and morphological properties using electron microscopy (EM), X-ray diffraction (XRD), infrared (IR) spectroscopy and selective chemical dissolution. In addition, we ran colloidal dispersion, wetting/drying, and freeze/thaw experiments. In the regolith, we observed concentrations of short-range ordered (SRO) phases similar to those observed in warmer, wetter volcanic ash soils. IR and EM analyses of the clay-sized fraction were consistent with allophane as the predominant secondary phase. Selective chemical extractions targeting SRO phases indicated lower Al/Si ratios than those observed in volcanic soils reported in warmer localities, which we attribute to Si-rich allophane and/or abundant Si-rich rock coatings. The oxic circumneutral-pH colloidal dispersion experiments mobilized Al, Fe and Ti primarily as 260-415 nm particles and Ca, Mg and Na as solutes. Si was lost both in the colloidal and dissolved forms. Dispersed colloids likely contain allophane and ferrihydrite. Under anoxic conditions, dissolution of Fe oxide cements also released fines. The experiments help to explain elemental loss from the clay-sized regolith fraction at Svalbard: observed depletions in Ca, K, Mg and Na were likely due to solute loss, while particle-reactive Al, Fe, Si and Ti were mostly retained. Wetting/drying was observed to be as effective as freeze/thaw in driving material loss. It is thus possible that cyclic adsorption of water onto basaltic rocks in this dry climate may result

  9. A comparison of two different processing chemicals for mammography: Repercussion on dose to patients

    International Nuclear Information System (INIS)

    The main technical objective of screen-film mammography is to reach the best image quality with the lowest dose to the breast. Sensitometric gradient and speed are factors related to both subjects respectively. For a given choice of film, these factors are affected by processing variables. For this reason, manufacturers have developed different types of films that are recommended for particular processing conditions. The purpose of this work is to compare the variations of both sensitometric characteristics of mammographic screen and film systems induced by two different manufactured chemicals: RPX-Omat EX/LO (Kodak) and G139/G334 (Agfa). A comparison of thirteen mammographic films by means of light sensitometry was performed at different processing conditions: 90s/Kodak, 120s/Kodak, 180s/Kodak, 90s/Agfa, 120s/Agfa and 180s/Agfa. Secondly, 99 combinations of screens and films were evaluated by X-ray sensitometry at 120s/Kodak and 120s/Agfa processing. At light sensitometry, variations in processing time led to different modifications in film speed, depending on the chemicals used. At X-Ray sensitometry, Agfa chemicals induced higher values of sensitivity for almost all combinations, while Kodak chemicals gave higher gradient/speed quotient. The results show that dose to patients in mammography and image contrast are highly dependent on the chemicals selected at medium cycle (120s) processing. (author)

  10. The top 50 commodity chemicals: Impact of catalytic process limitations on energy, environment, and economics

    Energy Technology Data Exchange (ETDEWEB)

    Tonkovich, A.L.Y.; Gerber, M.A.

    1995-08-01

    The production processes for the top 50 U.S. commodity chemicals waste energy, generate unwanted byproducts, and require more than a stoichiometric amount of feedstocks. Pacific Northwest Laboratory has quantified this impact on energy, environment, and economics for the catalytically produced commodity chemicals. An excess of 0.83 quads of energy per year in combined process and feedstock energy is required. The major component, approximately 54%, results from low per-pass yields and the subsequent separation and recycle of unreacted feedstocks. Furthermore, the production processes, either directly or through downstream waste treatment steps, release more than 20 billion pounds of carbon dioxide per year to the environment. The cost of the wasted feedstock exceeds 2 billion dollars per year. Process limitations resulting from unselective catalysis and unfavorable reaction thermodynamic constraints are the major contributors to this waste. Advanced process concepts that address these problems in an integrated manner are needed to improve process efficiency, which would reduce energy and raw material consumption, and the generation of unwanted byproducts. Many commodity chemicals are used to produce large volume polymer products. Of the energy and feedstock wasted during the production of the commodity chemicals, nearly one-third and one-half, respectively, represents chemicals used as polymer precursors. Approximately 38% of the carbon dioxide emissions are generated producing polymer feedstocks.

  11. Equilibrium thermodynamic analyses of methanol production via a novel Chemical Looping Carbon Arrestor process

    International Nuclear Information System (INIS)

    Highlights: • A novel Chemical Looping Carbon Arrestor Reforming process has been developed. • Energy efficiency of the process is found to be ∼64–70%. • The process emits only about 0.14 mole of carbon dioxide per mole of methanol. • The process offers an efficient and low-emission option for methanol production. - Abstract: Methanol economy is considered as an alternative to hydrogen economy due to the better handling and storage characteristics of methanol fuel than liquid hydrogen. This paper is concerned about a comprehensive equilibrium thermodynamic analysis carried out on methanol production via an innovative Chemical Looping Carbon Arrestor/Reforming process being developed at the University of Newcastle in order to reduce both energy consumption and carbon emissions. The detailed simulation revealed thermodynamic limitations within the Chemical Looping Carbon Reforming process however on the other hand it also confirmed that the new concept is a low energy requirement and low emission option compared to other methanol production technologies. Specifically, the mass and energy balance study showed that the Chemical Looping Carbon Reforming process typically consumes approximately 0.76–0.77 mole methane, 0.25–0.27 mole carbon dioxide, 0.49–0.50 mole water, and 0.51 mole iron oxide (in a chemical looping manner) per mole of methanol production. Moreover, the energy efficiency of Chemical Looping Carbon Reforming process was found to be ∼64–70% and its emission profile was found as low as 0.14 mole carbon dioxide per mole of methanol, which is about 82–88% less than the conventional methanol production process and well below the emission levels of other emerging methanol production technologies

  12. WEATHER INDEX- THE BASIS OF WEATHER DERIVATIVES

    Directory of Open Access Journals (Sweden)

    Botos Horia Mircea

    2011-07-01

    Full Text Available This paper approaches the subject of Weather Derivatives, more exactly their basic element the weather index. The weather index has two forms, the Heating Degree Day (HDD and the Cooling Degree Day (CDD. We will try to explain their origin, use and the relationship between the two forms of the index. In our research we started from the analysis of the weather derivatives and what they are based on. After finding out about weather index, we were interested in understanding exactly how they work and how they influence the value of the contract. On the national level the research in the field is scares, but foreign materials available. The study for this paper was based firstly on reading about Weather Derivative, and then going in the meteorogical field and determining the way by which the indices were determined. After this, we went to the field with interest in the indices, such as the energy and gas industries, and figured out how they determined the weather index. For the examples we obtained data from the weather index database, and calculated the value for the period. The study is made on a period of five years, in 8 cities of the European Union. The result of this research is that we can now understand better the importance of the way the indices work and how they influence the value of the Weather Derivatives. This research has an implication on the field of insurance, because of the fact that weather derivative are at the convergence point of the stock markets and the insurance market. The originality of the paper comes from the personal touch given to the theoretical aspect and through the analysis of the HDD and CDD index in order to show their general behaviour and relationship.

  13. Boundary-layer turbulent processes and mesoscale variability represented by numerical weather prediction models during the BLLAST campaign

    Science.gov (United States)

    Couvreux, Fleur; Bazile, Eric; Canut, Guylaine; Seity, Yann; Lothon, Marie; Lohou, Fabienne; Guichard, Françoise; Nilsson, Erik

    2016-07-01

    This study evaluates the ability of three operational models, with resolution varying from 2.5 to 16 km, to predict the boundary-layer turbulent processes and mesoscale variability observed during the Boundary Layer Late-Afternoon and Sunset Turbulence (BLLAST) field campaign. We analyse the representation of the vertical profiles of temperature and humidity and the time evolution of near-surface atmospheric variables and the radiative and turbulent fluxes over a total of 12 intensive observing periods (IOPs), each lasting 24 h. Special attention is paid to the evolution of the turbulent kinetic energy (TKE), which was sampled by a combination of independent instruments. For the first time, this variable, a central one in the turbulence scheme used in AROME and ARPEGE, is evaluated with observations.In general, the 24 h forecasts succeed in reproducing the variability from one day to another in terms of cloud cover, temperature and boundary-layer depth. However, they exhibit some systematic biases, in particular a cold bias within the daytime boundary layer for all models. An overestimation of the sensible heat flux is noted for two points in ARPEGE and is found to be partly related to an inaccurate simplification of surface characteristics. AROME shows a moist bias within the daytime boundary layer, which is consistent with overestimated latent heat fluxes. ECMWF presents a dry bias at 2 m above the surface and also overestimates the sensible heat flux. The high-resolution model AROME resolves the vertical structures better, in particular the strong daytime inversion and the thin evening stable boundary layer. This model is also able to capture some specific observed features, such as the orographically driven subsidence and a well-defined maximum that arises during the evening of the water vapour mixing ratio in the upper part of the residual layer due to fine-scale advection. The model reproduces the order of magnitude of spatial variability observed at

  14. A systematic synthesis and design methodology to achieve process intensification in (bio) chemical processes

    DEFF Research Database (Denmark)

    Lutze, Philip; Woodley, John; Gani, Rafiqul

    Process intensification (PI) has the potential to improve existing processes or create new process options which are needed in order to produce products using more sustainable methods. Potentially, PI creates an enormous number of process options. For identification where and how the process should...... be intensified for biggest improvement, process synthesis and design tools are applied which results in the development of a systematic methodology incorporating PI. In order to manage the complexity of PI process options in which a feasible and optimal process solution may exist, the solution...... procedure of this methodology is based on the decomposition approach. Starting from an analysis of existing processes, this methodology generates a set of feasible process options and reduces their number through several screening steps until from the remaining feasible options, the optimal is found. In...

  15. Extreme Compression of Weather Radar Data

    OpenAIRE

    Makkapati, Vishnu V; Mahapatra, Pravas R

    2007-01-01

    A method for achieving extreme levels of compression of high-volume weather radar data is presented. Weather reflectivity contours, as per National Weather Service or custom thresholds, are processed by tracing their departure from a smoothed version to obtain the local extrema which serve as control points. The control points, which are transmitted in relative coordinates for further compression, are interpolated using a second-degree B- spline to retrieve the contours. The encoding–decoding...

  16. Application showcases for a small scale membrane contactor for fine chemical processes

    NARCIS (Netherlands)

    Roelands, C.P.M.; Ngene, I.S.

    2011-01-01

    The transition from batch to continuous processing in fine-chemicals industries offers many advantages; among these are a high volumetric productivity, improved control over reaction conditions resulting in a higher yield and selectivity, a small footprint and a safer process due to a smaller reacti

  17. The role of impacting processes in the chemical evolution of the atmosphere of primordial Earth

    Science.gov (United States)

    Mukhin, Lev M.; Gerasimov, M. V.

    1991-01-01

    The role of impacting processes in the chemical evolution of the atmosphere of primordial Earth is discussed. The following subject areas are covered: (1) Earth's initial atmosphere; (2) continuous degassing; (3) impact processes and the Earth's protoatmosphere; and (4) the evolution of an impact-generated atmosphere.

  18. Process intensification in the future production of base chemicals from biomass

    NARCIS (Netherlands)

    Sanders, J. P. M.; Clark, J. H.; Harmsen, G. J.; Heeres, H. J.; Kersten, S. R. A.; Van Swaaij, W. P. M.; Moulijn, J. A.; Heijnen, Johannes

    2012-01-01

    Biomass is an attractive resource for the production of bulk chemicals. Process intensification (PI) is a valuable approach in developing economical processes with a minimal global footprint which will require new infrastructure to be designed and built. An attempt is presented to describe the futur

  19. Multivariate Statistical Process Monitoring and Control:Recent Developments and Applications to Chemical Industry

    Institute of Scientific and Technical Information of China (English)

    梁军; 钱积新

    2003-01-01

    Multivariate statistical process monitoring and control (MSPM& C) methods for chemical process monitoring with statistical projection techniques such as principal component analysis (PCA) and partial least squares (PLS) are surveyed in this paper,The four-step procedure of performing MSPM &C for chemical process ,modeling of processes ,detecting abnormal events or faults,identifying the variable(s) responible for the faults and diagnosing the source cause for the abnormal behavior,is analyzed,Several main research directions of MSPM&C reported in the literature are discussed,such as multi-way principal component analysis (MPCA) for batch process ,statistical monitoring and control for nonlinear process,dynamic PCA and dynamic PLS,and on -line quality control by infer-ential models,Industrial applications of MSPM&C to several typical chemical processes ,such as chemical reactor,distillation column,polymeriztion process ,petroleum refinery units,are summarized,Finally,some concluding remarks and future considerations are made.

  20. 29 CFR 1926.64 - Process safety management of highly hazardous chemicals.

    Science.gov (United States)

    2010-07-01

    ... materials that could foreseeably occur. Note: Material Safety Data Sheets meeting the requirements of 29 CFR... 29 Labor 8 2010-07-01 2010-07-01 false Process safety management of highly hazardous chemicals... Health and Environmental Controls § 1926.64 Process safety management of highly hazardous...

  1. Model Reduction in Chemical Engineering: Case studies applied to process analysis, design and operation

    NARCIS (Netherlands)

    Dorneanu, B.

    2011-01-01

    During the last decades, models have become widely used for supporting a broad range of chemical engineering activities, such as product and process design and development, process monitoring and control, real time optimization of plant operation or supply chain management. Although tremendous advan

  2. Internet Weather Source

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Weather Service (NWS) National Telecommunications Gateway provides weather, hydrologic, and climate forecasts and warnings for the United States, its...

  3. Pilot Weather Reports

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Aviation weather reports relayed from pilots to FAA air traffic controllers or National Weather Service personnel. Elements include sky cover, turbulence, wind...

  4. Land Surface Weather Observations

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — METAR is the international standard code format for hourly surface weather observations. The acronym roughly translates from French as Aviation Routine Weather...

  5. Surface Weather Observations Hourly

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Standard hourly observations taken at Weather Bureau/National Weather Service offices and airports throughout the United States. Hourly observations began during...

  6. Daily Weather Records

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These daily weather records were compiled from a subset of stations in the Global Historical Climatological Network (GHCN)-Daily dataset. A weather record is...

  7. Cold Weather Pet Safety

    Science.gov (United States)

    ... Emergency Care Animal Welfare Veterinary Careers Public Health Cold Weather Pet Safety Client Handout Available for download ... in hot cars , but did you know that cold weather also poses serious threats to your pets’ ...

  8. Weather Radar Stations

    Data.gov (United States)

    Department of Homeland Security — These data represent Next-Generation Radar (NEXRAD) and Terminal Doppler Weather Radar (TDWR) weather radar stations within the US. The NEXRAD radar stations are...

  9. Surface Weather Observing Manuals

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Manuals and instructions for taking weather observations. Includes the annual Weather Bureau 'Instructions for Preparing Meteorological Forms...' and early airways...

  10. Winter Weather Emergencies

    Science.gov (United States)

    Severe winter weather can lead to health and safety challenges. You may have to cope with Cold related health problems, including ... there are no guarantees of safety during winter weather emergencies, you can take actions to protect yourself. ...

  11. Winter Weather: Indoor Safety

    Science.gov (United States)

    ... Health Matters What's New Preparation & Planning Disasters & Severe Weather Earthquakes Extreme Heat Floods Hurricanes Landslides Tornadoes Tsunamis ... Outdoor Safety Winter PSAs and Podcasts Disasters & Severe Weather Earthquakes Extreme Heat Floods Hurricanes Landslides Tornadoes Tsunamis ...

  12. Winter Weather: Frostbite

    Science.gov (United States)

    ... Health Matters What's New Preparation & Planning Disasters & Severe Weather Earthquakes Extreme Heat Floods Hurricanes Landslides Tornadoes Tsunamis ... related health problems. More Information: Hypothermia Disasters & Severe Weather Earthquakes Extreme Heat Floods Hurricanes Landslides Tornadoes Tsunamis ...

  13. National Convective Weather Diagnostic

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Current convective hazards identified by the National Convective Weather Detection algorithm. The National Convective Weather Diagnostic (NCWD) is an automatically...

  14. Assessment of impacts at the advanced test reactor as a result of chemical releases at the Idaho Chemical Processing Plant

    International Nuclear Information System (INIS)

    This report provides an assessment of potential impacts at the Advanced Test Reactor Facility (ATR) resulting from accidental chemical spill at the Idaho Chemical Processing Plant (ICPP). Spills postulated to occur at the Lincoln Blvd turnoff to ICPP were also evaluated. Peak and time weighted average concentrations were calculated for receptors at the ATR facility and the Test Reactor Area guard station at a height above ground level of 1.0 m. Calculated concentrations were then compared to the 15 minute averaged Threshold Limit Value - Short Term Exposure Limit (TLV-STEL) and the 30 minute averaged Immediately Dangerous to Life and Health (IDLH) limit. Several different methodologies were used to estimate source strength and dispersion. Fifteen minute time weighted averaged concentrations of hydrofluoric acid and anhydrous ammonia exceeded TLV-STEL values for the cases considered. The IDLH value for these chemicals was not exceeded. Calculated concentrations of ammonium hydroxide, hexone, nitric acid, propane, gasoline, chlorine and liquid nitrogen were all below the TLV-STEL value

  15. Micro-fluidic partitioning between polymeric sheets for chemical amplification and processing

    Science.gov (United States)

    Anderson, Brian L.

    2015-05-26

    A system for fluid partitioning for chemical amplification or other chemical processing or separations of a sample, comprising a first dispenser of a first polymeric sheet, wherein the first polymeric sheet contains chambers; a second dispenser of a second polymeric sheet wherein the first dispenser and the second dispenser are positioned so that the first polymeric sheet and the second polymeric sheet become parallel; a dispenser of the fluid positioned to dispense the fluid between the first polymeric sheet and the second polymeric sheet; and a seal unit that seals the first polymeric sheet and the second polymeric sheet together thereby sealing the sample between the first polymeric sheet and the second polymeric sheet and partitioning the fluid for chemical amplification or other chemical processing or separations.

  16. Improved ADM1 model for anaerobic digestion process considering physico-chemical reactions.

    Science.gov (United States)

    Zhang, Yang; Piccard, Sarah; Zhou, Wen

    2015-11-01

    The "Anaerobic Digestion Model No. 1" (ADM1) was modified in the study by improving the bio-chemical framework and integrating a more detailed physico-chemical framework. Inorganic carbon and nitrogen balance terms were introduced to resolve the discrepancies in the original bio-chemical framework between the carbon and nitrogen contents in the degraders and substrates. More inorganic components and solids precipitation processes were included in the physico-chemical framework of ADM1. The modified ADM1 was validated with the experimental data and used to investigate the effects of calcium ions, magnesium ions, inorganic phosphorus and inorganic nitrogen on anaerobic digestion in batch reactor. It was found that the entire anaerobic digestion process might exist an optimal initial concentration of inorganic nitrogen for methane gas production in the presence of calcium ions, magnesium ions and inorganic phosphorus. PMID:26253912

  17. Factors Influencing Biotite Weathering

    OpenAIRE

    Reed, Ryan R.

    2000-01-01

    Factors Influencing Biotite Weathering by Ryan Reed Lucian W. Zelazny, Chairman Crop and Soil Environmental Sciences (ABSTRACT) Weathering of biotite supplies nutrients such as K+ and weathers into vermiculite/montmorillonite or kaolinite, which have varying influences on soil properties and characteristics. This study was conducted to determine if the weathering mechanisms of biotite are controlled by temperature, or if other factors, such as vegetation or leaching inten...

  18. Active biopolymers in green non-conventional media: a sustainable tool for developing clean chemical processes.

    Science.gov (United States)

    Lozano, Pedro; Bernal, Juana M; Nieto, Susana; Gomez, Celia; Garcia-Verdugo, Eduardo; Luis, Santiago V

    2015-12-21

    The greenness of chemical processes turns around two main axes: the selectivity of catalytic transformations, and the separation of pure products. The transfer of the exquisite catalytic efficiency shown by enzymes in nature to chemical processes is an important challenge. By using appropriate reaction systems, the combination of biopolymers with supercritical carbon dioxide (scCO2) and ionic liquids (ILs) resulted in synergetic and outstanding platforms for developing (multi)catalytic green chemical processes, even under flow conditions. The stabilization of biocatalysts, together with the design of straightforward approaches for separation of pure products including the full recovery and reuse of enzymes/ILs systems, are essential elements for developing clean chemical processes. By understanding structure-function relationships of biopolymers in ILs, as well as for ILs themselves (e.g. sponge-like ionic liquids, SLILs; supported ionic liquids-like phases, SILLPs, etc.), several integral green chemical processes of (bio)catalytic transformation and pure product separation are pointed out (e.g. the biocatalytic production of biodiesel in SLILs, etc.). Other developments based on DNA/ILs systems, as pathfinder studies for further technological applications in the near future, are also considered. PMID:26497761

  19. Assessment of oil weathering by gas chromatography-mass spectrometry, time warping and principal component analysis

    DEFF Research Database (Denmark)

    Malmquist, Linus M.V.; Olsen, Rasmus R.; Hansen, Asger B.;

    2007-01-01

    Detailed characterization and understanding of oil weathering at the molecular level is an essential part of tiered approaches for forensic oil spill identification, for risk assessment of terrestrial and marine oil spills, and for evaluating effects of bioremediation initiatives. Here, a...... chemometricbased method is applied to data from two in vitro experiments in order to distinguish the effects of evaporation and dissolution processes on oil composition. The potential of the method for obtaining detailed chemical information of the effects from evaporation and dissolution processes, to determine...... weathering state and to distinguish between various weathering processes is investigated and discussed. The method is based on comprehensive and objective chromatographic data processing followed by principal component analysis (PCA) of concatenated sections of gas chromatography–mass spectrometry...

  20. The Lyophilization Process Maintains the Chemical and Biological Characteristics of Royal Jelly

    OpenAIRE

    Andresa Piacezzi Nascimento; Larissa Ariana Roveroni Moraes; Nathália Ursoli Ferreira; Gabriela de Padua Moreno; Fernanda Grassi Mangolini Uahib; Edna Aparecida Barizon; Andresa Aparecida Berretta

    2015-01-01

    The alternative use of natural products, like royal jelly (RJ), may be an important tool for the treatment of infections caused by antibiotic-resistant bacteria. RJ presents a large number of bioactive substances, including antimicrobial compounds. In this study, we carried out the chemical characterization of fresh and lyophilized RJ and investigated their antibacterial effects with the purpose of evaluating if the lyophilization process maintains the chemical and antibacterial properties of...