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Sample records for lwr water chemistry

  1. Hybrid method for numerical modelling of LWR coolant chemistry

    NASA Astrophysics Data System (ADS)

    Swiatla-Wojcik, Dorota

    2016-10-01

    A comprehensive approach is proposed to model radiation chemistry of the cooling water under exposure to neutron and gamma radiation at 300 °C. It covers diffusion-kinetic processes in radiation tracks and secondary reactions in the bulk coolant. Steady-state concentrations of the radiolytic products have been assessed based on the simulated time dependent concentration profiles. The principal reactions contributing to the formation of H2, O2 and H2O2 were indicated. Simulation was carried out depending on the amount of extra hydrogen dissolved in the coolant to reduce concentration of corrosive agents. High sensitivity to the rate of reaction H+H2O=OH+H2 is shown and discussed.

  2. Nature of corrosion films in simulated LWR water. Final report

    SciTech Connect

    Lumsden, J.B.

    1985-06-01

    Passive films on Alloy 600 and Type 304 stainless steel were characterized using surface analysis instruments. The films were formed under conditions suspected of causing cracking in nuclear systems and compared to those formed under conditions where cracking does not occur. Alloy 600 was investigated in the boric acid-lithium hydroxide thiosulfate solution. Susceptibility to stress corrosion cracking was correlated with the occurrence of a film containing sulfide ions. Environmental conditions which produce an oxide film do not cause stress corrosion cracking of Alloy 600 in the system studied. Type 304 stainless steel was investigated in high purity water at 288/sup 0/C having levels of dissolved O/sub 2/ where Type 304 stainless steel is susceptible and not susceptible to stress corrosion cracking. A correlation was found between passive film chemistry and susceptibility to stress corrosion cracking.

  3. Recycle of LWR (Light Water Reactor) actinides to an IFR (Integral Fast Reactor)

    SciTech Connect

    Pierce, R.D.; Ackerman, J.P.; Johnson, G.K.; Mulcahey, T.P.; Poa, D.S.

    1991-01-01

    A large quantity of actinide elements is present in irradiated Light Water Reactor (LWR) fuel that is stored throughout the world. Because of the high fission-to-capture ratio for the transuranium (TRU) elements with the high-energy neutrons in the metal-fueled Integral Fast Reactor (IFR), that reactor can consume these elements effectively. The stored fuel represents a valuable resource for an expanding application of fast power reactors. In addition, removal of the TRU elements from the spent LWR fuel has the potential for increasing the capacity of a high-level waste facility by reducing the heat loads and increasing the margin of safety in meeting licensing requirements. Argonne National Laboratory (ANL) is developing a pyrochemical process, which is compatible with the IFR fuel cycle, for the recovery of TRU elements from LWR fuel. The proposed product is a metallic actinide ingot, which can be introduced into the electrorefining step of the IFR process. The major objective of the LWR fuel recovery process is high TRU element recovery, with decontamination a secondary issue, because fission product removal is accomplished in the IFR process. The extensive pyrochemical processing studies of the 1960s and 1970s provide a basis for the design of possible processes. Two processes were selected for laboratory-scale investigation. One is based on the Salt Transport Process studied at ANL for mixed-oxide fast reactor fuel, and the other is based on the blanket processing studies done for ANL's second Experimental Breeder Reactor (EBR-2). This paper discusses the two processes and is a status report on the experimental studies. 5 refs., 2 figs., 2 tabs.

  4. TREAT Neutronics Analysis of Water-Loop Concept Accommodating LWR 9-rod Bundle

    SciTech Connect

    Hill, Connie M.; Woolstenhulme, Nicolas E.; Parry, James R.; Bess, John D.; Housley, Gregory K.

    2016-09-01

    Abstract. Simulation of a variety of transient conditions has been successfully achieved in the Transient Reactor Test (TREAT) facility during operation between 1959 and 1994 to support characterization and safety analysis of nuclear fuels and materials. A majority of previously conducted tests were focused on supporting sodium-cooled fast reactor (SFR) designs. Experiments evolved in complexity. Simulation of thermal-hydraulic conditions expected to be encountered by fuels and materials in a reactor environment was realized in the development of TREAT sodium loop experiment vehicles. These loops accommodated up to 7-pin fuel bundles and served to simulate more closely the reactor environment while safely delivering large quantities of energy into the test specimen. Some of the immediate TREAT restart operations will be focused on testing light water reactor (LWR) accident tolerant fuels (ATF). Similar to the sodium loop objectives, a water loop concept, developed and analyzed in the 1990’s, aimed at achieving thermal-hydraulic conditions encountered in commercial power reactors. The historic water loop concept has been analyzed in the context of a reactivity insertion accident (RIA) simulation for high burnup LWR 2-pin and 3-pin fuel bundles. Findings showed sufficient energy could be deposited into the specimens for evaluation. Similar results of experimental feasibility for the water loop concept (past and present) have recently been obtained using MCNP6.1 with ENDF/B-VII.1 nuclear data libraries. The old water loop concept required only two central TREAT core grid spaces. Preparation for future experiments has resulted in a modified water loop conceptual design designated the TREAT water environment recirculating loop (TWERL). The current TWERL design requires nine TREAT core grid spaces in order to place the water recirculating pump under the TREAT core. Due to the effectiveness of water moderation, neutronics analysis shows that removal of seven additional

  5. Microstructural examination of fatigue accumulation in critical LWR (light water reactor) components: Final report

    SciTech Connect

    Allen, A.J.; Buttle, D.J.; Coleman, C.F.; Smith, F.A.; Smith, R.L.

    1988-01-01

    This report describes a morphological study of the feasibility of measuring the fatigue damage accumulation state of critical light water reactor (LWR) components by microstructural examination. The changes in microstructure associated with fatigue processes are first discussed so that relevant NDE measurement parameters can be identified. (The creep regime is not considered in this report). The candidate NDE techniques are then reviewed in detail under the following headings: positron annihilation, x-ray diffraction, magnetic techniques, the magnetic Barkhausen effect, the magneto acoustic technique, acoustic emission, ultrasonic techniques and finally other miscellaneous techniques applicable to fatigue damage assessment. All the feasible techniques are summarised and rated in a set of comparison tables. A possible programme for the immediate development of the positron annihilation lineshape technique is proposed. It is concluded that the most successful method of measuring the fatigue accumulation in LWR critical components in a way which relates to the intent of the ASME pressure vessel codes, is likely to be the use of several techniques together and the cross-relation of the results obtained by each. Five techniques are highlighted for immediate possible development: 'etching and surface replication', 'positron annihilation lineshapes', 'x-ray diffraction residual stress', 'acoustic emission' and 'ultrasonic surface acoustic waves'.

  6. Integrated Computational Modeling of Water Side Corrosion in Zirconium Metal Clad Under Nominal LWR Operating Conditions

    NASA Astrophysics Data System (ADS)

    Aryanfar, Asghar; Thomas, John; Van der Ven, Anton; Xu, Donghua; Youssef, Mostafa; Yang, Jing; Yildiz, Bilge; Marian, Jaime

    2016-11-01

    A mesoscopic chemical reaction kinetics model to predict the formation of zirconium oxide and hydride accumulation light-water reactor (LWR) fuel clad is presented. The model is designed to include thermodynamic information from ab initio electronic structure methods as well as parametric information in terms of diffusion coefficients, thermal conductivities and reaction constants. In contrast to approaches where the experimentally observed time exponents are captured by the models by design, our approach is designed to be predictive and to provide an improved understanding of the corrosion process. We calculate the time evolution of the oxide/metal interface and evaluate the order of the chemical reactions that are conducive to a t 1/3 dependence. We also show calculations of hydrogen cluster accumulation as a function of temperature and depth using spatially dependent cluster dynamics. Strategies to further cohesively integrate the different elements of the model are provided.

  7. Potential-pH diagrams for alloy-water systems under LWR conditions

    NASA Astrophysics Data System (ADS)

    Cubicciotti, Daniel

    Potential-pH diagrams, which present the regions of stability of metallic species with water, are generally known as Pourbaix diagrams. They are especially useful to corrosion scientists because the diagrams indicate the areas of potential and pH in which oxides of the metal are stable and thus the regions in which an oxide corrosion layer can form on the metal, protecting it from corrosion. Potential-pH diagrams are generally available for the metallic elements, even at high temperature (up to about 600 K). But rarely is a pure metal used as a construction material. Stainless steel, which is an alloy of iron, chromium, and nickel plus some trace elements, is often used as a construction material for water systems because of its good corrosion resistance. The oxides in equilibrium with the water-Fe-Cr-Ni system are generally mixed metal oxides. In this paper, Pourbaix diagrams for this system are calculated from thermodynamic values at room temperature and at typical LWR (light water reactor) temperature. Diagrams for the ancilliary systems Fe-Cr-water, Fe-Ni-water and Cr-Ni-water are also given.

  8. Storage of LWR (light-water-reactor) spent fuel in air

    SciTech Connect

    Thomas, L.E.; Charlot, L.A.; Coleman, J.E. ); Knoll, R.W. )

    1989-12-01

    An experimental program is being conducted at Pacific Northwest Laboratory (PNL) to determine the oxidation response of light-water-reactor (LWR) spent fuels under conditions appropriate to fuel storage in air. The program is designed to investigate several independent variables that might affect the oxidation behavior of spent fuel. Included are temperature (135 to 230{degree}C), fuel burnup (to about 34 MWd/kgM), reactor type (pressurized and boiling water reactors), moisture level in the air, and the presence of a high gamma field. In continuing tests with declad spent fuel and nonirradiated UO{sub 2} specimens, oxidation rates were monitored by weight-gain measurements and the microstructures of subsamples taken during the weighing intervals were characterized by several analytical methods. The oxidation behavior indicated by weight gain and time to form powder will be reported in Volume III of this series. The characterization results obtained from x-ray diffractometry, transmission electron microscopy, scanning electron microscopy, and Auger electron spectrometry of oxidized fuel samples are presented in this report. 28 refs., 21 figs., 3 tabs.

  9. Water Chemistry: Seeking Information

    ERIC Educational Resources Information Center

    Delfino, Joseph J.

    1977-01-01

    A survey of the available literature in water chemistry is presented. Materials surveyed include: texts, reference books, bibliographic resources, journals, American Chemical Society publications, proceedings, unpublished articles, and reports. (BT)

  10. Water Chemistry Laboratory Manual.

    ERIC Educational Resources Information Center

    Jenkins, David; And Others

    This manual of laboratory experiments in water chemistry serves a dual function of illustrating fundamental chemical principles of dilute aqueous systems and of providing the student with some familiarity with the chemical measurements commonly used in water and wastewater analysis. Experiments are grouped in categories on the basis of similar…

  11. Water Chemistry Laboratory Manual.

    ERIC Educational Resources Information Center

    Jenkins, David; And Others

    This manual of laboratory experiments in water chemistry serves a dual function of illustrating fundamental chemical principles of dilute aqueous systems and of providing the student with some familiarity with the chemical measurements commonly used in water and wastewater analysis. Experiments are grouped in categories on the basis of similar…

  12. Extended-burnup LWR (light-water reactor) fuel: The amount, characteristics, and potential effects on interim storage

    SciTech Connect

    Bailey, W.J.

    1989-03-01

    The results of a study on extended-burnup, light-water reactor (LWR) spent fuel are described in this report. The study was performed by Pacific Northwest Laboratory for the US Department of Energy (DOE). The purpose of the study was to collect and evaluate information on the status of in-reactor performance and integrity of extended-burnup LWR fuel and initiate the investigation of the effects of extending fuel burnup on the subsequent handling, interim storage, and other operations (e.g., rod consolidation and shipping) associated with the back end of the fuel cycle. The results of this study will aid DOE and the nuclear industry in assessing the effects on waste management of extending the useful in-reactor life of nuclear fuel. The experience base with extended-burnup fuel is now substantial and projections for future use of extended-burnup fuel in domestic LWRs are positive. The basic performance and integrity of the fuel in the reactor has not been compromised by extending the burnup, and the potential limitations for further extending the burnup are not severe. 104 refs., 15 tabs.

  13. A review of irradiation effects on LWR core internal materials - IASCC susceptibility and crack growth rates of austenitic stainless steels

    NASA Astrophysics Data System (ADS)

    Chopra, O. K.; Rao, A. S.

    2011-02-01

    Austenitic stainless steels (SSs) are used extensively as structural alloys in the internal components of light water reactor (LWR) pressure vessels because of their relatively high strength, ductility, and fracture toughness. However, exposure to neutron irradiation for extended periods changes the microstructure (radiation hardening) and microchemistry (radiation-induced segregation) of these steels, and degrades their fracture properties. Irradiation-assisted stress corrosion cracking (IASCC) is another degradation process that affects LWR internal components exposed to neutron radiation. The existing data on irradiated austenitic SSs were reviewed to evaluate the effects of key parameters such as material composition, irradiation dose, and water chemistry on IASCC susceptibility and crack growth rates of these materials in LWR environments. The significance of microstructural and microchemistry changes in the material on IASCC susceptibility is also discussed. The results are used to determine (a) the threshold fluence for IASCC and (b) the disposition curves for cyclic and IASCC growth rates for irradiated SSs in LWR environments.

  14. A review of irradiation effects on LWR core internal materials - IASCC susceptibility and crack growth rates of austenitic stainless steels.

    SciTech Connect

    Chopra, O. K.; Roa, A. S.; Environmental Science Division; U.S. NRC

    2010-12-15

    Austenitic stainless steels (SSs) are used extensively as structural alloys in the internal components of light water reactor (LWR) pressure vessels because of their relatively high strength, ductility, and fracture toughness. However, exposure to neutron irradiation for extended periods changes the microstructure (radiation hardening) and microchemistry (radiation-induced segregation) of these steels, and degrades their fracture properties. Irradiation-assisted stress corrosion cracking (IASCC) is another degradation process that affects LWR internal components exposed to neutron radiation. The existing data on irradiated austenitic SSs were reviewed to evaluate the effects of key parameters such as material composition, irradiation dose, and water chemistry on IASCC susceptibility and crack growth rates of these materials in LWR environments. The significance of microstructural and microchemistry changes in the material on IASCC susceptibility is also discussed. The results are used to determine (a) the threshold fluence for IASCC and (b) the disposition curves for cyclic and IASCC growth rates for irradiated SSs in LWR environments.

  15. Water chemistry and poultry processing water quality

    USDA-ARS?s Scientific Manuscript database

    This study examined the influences of water chemistry on the quality of process water used in immersion chillers. During commercial poultry processing the bird carcasses come in direct contact with process water during washing and chilling operations. Contamination of the process water with bacteria...

  16. A subchannel analysis code for supercritical-pressure LWR with downward-flowing water rods

    SciTech Connect

    Tanabe, T.; Koshizuka, S.; Oka, Y.; Kitou, K.

    2004-07-01

    This paper describes development of a subchannel analysis code for the square fuel assembly with downward-flowing water rods, which is the new design of high temperature thermal reactor (SCLWR-H) in Univ. Tokyo. PLANDTL experiment for liquid metal cooled fast breeder reactor and ASFRE-III code analysis are used to verify the present code. Subchannel analysis for SCLWR-H, which considers the effect of water rods, is executed. Since the hydraulic diameters of the subchannels are almost constant in the square fuel assembly, the flow and temperature distributions are more uniform than those in the hexagonal assembly. However, coolant temperature slightly depends on the subchannel types. The temperature in the corner subchannels is the lowest. This is because flow area is small against the contact length with the water rod and heat transfer to the water rod is larger than that in other subchannels. The coolant temperature in the corner subchannels is 17 deg. C lower than the average temperature (500 deg. C). The temperature distributions in the water rods are also evaluated. The water rods outside the channel box have a higher temperature distribution than that in the inside water rods. The temperature in the outside water rods increases up to 378 deg. C which is close to pseudo-critical temperature. It can be reduced by increasing the flow rate in the outside water rods. (authors)

  17. Neutron collar calibration for assay of LWR (light-water reactor) fuel assemblies

    SciTech Connect

    Menlove, H.O.; Pieper, J.E.

    1987-03-01

    The neutron-coincidence collar is used for the verification of the uranium content in light-water reactor fuel assemblies. An AmLi neutron source is used to give an active interrogation of the fuel assembly to measure the /sup 235/U content, and the /sup 238/U content is verified from a passive neutron-coincidence measurement. This report gives the collar calibration data of pressurized-water reactor and boiling-water reactor fuel assemblies. Calibration curves and correction factors are presented for neutron absorbers (burnable poisons) and different fuel assembly sizes. The data were collected at Exxon Nuclear, Franco-Belge de Fabrication de Combustibles, ASEA-Atom, and other nuclear fuel fabrication facilities.

  18. Water Chemistry Education

    ERIC Educational Resources Information Center

    Hindin, Ervin

    1975-01-01

    Describes the purpose, content, and relevancy of courses dealing with natural and artificial aquatic environments, including surface water and ground water systems as well as water and waste treatment processes. Describes existing programs which are offered at the graduate level in this subject area. (MLH)

  19. Water Chemistry Education

    ERIC Educational Resources Information Center

    Hindin, Ervin

    1975-01-01

    Describes the purpose, content, and relevancy of courses dealing with natural and artificial aquatic environments, including surface water and ground water systems as well as water and waste treatment processes. Describes existing programs which are offered at the graduate level in this subject area. (MLH)

  20. Application of an intermediate LWR for electricity production and hot-water district heating

    SciTech Connect

    Not Available

    1983-05-01

    The objective of the study is to evaluate the technical and economic feasibility of a 400 MWe Consolidated Nuclear Steam System (CNSS) for supplying district heat to the Minneapolis/St. Paul area. A total of three CNSS reactor sites, located various distances from the Minneapolis-St. Paul area load center, are evaluated. The distance from the load center is determined by the credited safety features of the plant design. Each site is also evaluated for three different hot water supply/return temperatures providing a total of nine CNSS study cases. The cost of district heat delivered to the load center is determined for each case.

  1. European pressurized water reactor (EPR) - an advanced LWR to fit the needs of European utilities

    SciTech Connect

    Teichel, H.; Pouget-Abadie, X.

    1997-12-01

    The European Pressurized Water Reactor (EPR) is a project for the development of an advanced PWR pursued by Electricite de France and the major German utilities (RWEE, PreussenElektra, BAG et. al.) together with SIEMENS, Framatome and their common subsidiary NPI. In this project, the experience gained through the design, the erection, the commissioning and the operation of the existing PWR in France and Germany are combined and the existing technical solutions were carefully checked before adopted for the EPR. The deep involvement of the future operators since the beginning of the project guarantees an optimized operational behaviour and easy maintainability. 1 fig., 1 tab.

  2. Categorization of failed and damaged spent LWR (light-water reactor) fuel currently in storage

    SciTech Connect

    Bailey, W.J.

    1987-11-01

    The results of a study that was jointly sponsored by the US Department of Energy and the Electric Power Research Institute are described in this report. The purpose of the study was to (1) estimate the number of failed fuel assemblies and damaged fuel assemblies (i.e., ones that have sustained mechanical or chemical damage but with fuel rod cladding that is not breached) in storage, (2) categorize those fuel assemblies, and (3) prepare this report as an authoritative, illustrated source of information on such fuel. Among the more than 45,975 spent light-water reactor fuel assemblies currently in storage in the United States, it appears that there are nearly 5000 failed or damaged fuel assemblies. 78 refs., 23 figs., 19 tabs.

  3. LWR (Light Water Reactor) power plant simulations using the AD10 and AD100 systems

    SciTech Connect

    Wulff, W.; Cheng, H.S.; Chien, C.J.; Jang, J.Y.; Lin, H.C.; Mallen, A.N.; Wang, S.J.; Institute of Nuclear Energy Research, Lung-Tan; Tawian Power Co., Taipei; Brookhaven National Lab., Upton, NY; Institute of Nuclear Energy Research, Lung-Tan )

    1989-01-01

    Boiling (BWR) and Pressurized (PWR) Water Reactor Power Plants are being simulated at BNL with the AD10 and AD100 Peripheral Processor Systems. The AD10 system has been used for BWR simulations since 1984 for safety analyses, emergency training and optimization studies. BWR simulation capabilities have been implemented recently on the AD100 system and PWR simulation capabilities are currently being developed under the auspices of international cooperation. Modeling and simulation methods are presented with emphasis on the simulation of the Nuclear Steam Supply System. Results are presented for BWR simulation and performance characteristics are compared of the AD10 and AD100 systems. It will be shown that the AD100 simulates two times faster than two AD10 processors operating in parallel and that the computing capacity of one AD100 (with FMU processor) is twice as large as that of two AD10 processors. 9 refs., 5 figs., 1 tab.

  4. Green chemistry oriented organic synthesis in water.

    PubMed

    Simon, Marc-Olivier; Li, Chao-Jun

    2012-02-21

    The use of water as solvent features many benefits such as improving reactivities and selectivities, simplifying the workup procedures, enabling the recycling of the catalyst and allowing mild reaction conditions and protecting-group free synthesis in addition to being benign itself. In addition, exploring organic chemistry in water can lead to uncommon reactivities and selectivities complementing the organic chemists' synthetic toolbox in organic solvents. Studying chemistry in water also allows insight to be gained into Nature's way of chemical synthesis. However, using water as solvent is not always green. This tutorial review briefly discusses organic synthesis in water with a Green Chemistry perspective.

  5. Water, water everywhere, and its remarkable chemistry.

    PubMed

    Barber, Jim

    2004-04-12

    Photosystem II (PSII), the multisubunit pigment-protein complex localised in the thylakoid membranes of oxygenic photosynthetic organisms, uses light energy to drive a series of remarkable reactions leading to the oxidation of water. The products of this oxidation are dioxygen, which is released to the atmosphere, and reducing equivalents destined to reduce carbon dioxide to organic molecules. The water oxidation occurs at catalytic sites composed of four manganese atoms (Mn(4)-cluster) and powered by the redox potential of an oxidised chlorophyll a molecule (P680(*+)). Gerald T (Jerry) Babcock and colleagues showed that electron/proton transfer processes from substrate water to P680(*+) involved a tyrosine residue (Y(Z)) and proposed an attractive reaction mechanism for the direct involvement of Y(Z) in the chemistry of water oxidation. The 'hydrogen-atom abstract/metalloradical' mechanism he formulated is an expression of his genius and a highlight of his many other outstanding contributions to photosynthesis research. A structural basis for Jerry's model is now being revealed by X-ray crystallography.

  6. Perspective: Water cluster mediated atmospheric chemistry

    NASA Astrophysics Data System (ADS)

    Vaida, Veronica

    2011-07-01

    The importance of water in atmospheric and environmental chemistry initiated recent studies with results documenting catalysis, suppression and anti-catalysis of thermal and photochemical reactions due to hydrogen bonding of reagents with water. Water, even one water molecule in binary complexes, has been shown by quantum chemistry to stabilize the transition state and lower its energy. However, new results underscore the need to evaluate the relative competing rates between reaction and dissipation to elucidate the role of water in chemistry. Water clusters have been used successfully as models for reactions in gas-phase, in aqueous condensed phases and at aqueous surfaces. Opportunities for experimental and theoretical chemical physics to make fundamental new discoveries abound. Work in this field is timely given the importance of water in atmospheric and environmental chemistry.

  7. Perspective: Water cluster mediated atmospheric chemistry

    SciTech Connect

    Vaida, Veronica

    2011-07-14

    The importance of water in atmospheric and environmental chemistry initiated recent studies with results documenting catalysis, suppression and anti-catalysis of thermal and photochemical reactions due to hydrogen bonding of reagents with water. Water, even one water molecule in binary complexes, has been shown by quantum chemistry to stabilize the transition state and lower its energy. However, new results underscore the need to evaluate the relative competing rates between reaction and dissipation to elucidate the role of water in chemistry. Water clusters have been used successfully as models for reactions in gas-phase, in aqueous condensed phases and at aqueous surfaces. Opportunities for experimental and theoretical chemical physics to make fundamental new discoveries abound. Work in this field is timely given the importance of water in atmospheric and environmental chemistry.

  8. Fog water chemistry in Shanghai

    NASA Astrophysics Data System (ADS)

    Li, Pengfei; Li, Xiang; Yang, Chenyu; Wang, Xinjun; Chen, Jianmin; Collett, Jeffrey L., Jr.

    2011-08-01

    With the aim of understanding the fog chemistry in a Chinese megacity, twenty-six fog water samples were collected in urban Shanghai from March 2009 to March 2010. The following parameters were measured: pH, electrical conductivity (EC), ten inorganic major ions ( SO42-, NO3-, NO2-, F -, Cl -, Na +, K +, Ca 2+, Mg 2+, NH4+) and four major organic acids (CH 3COO -, HCOO -, CO42-, MSA). The total ionic concentration (TIC) and EC of fog samples were one or two orders of magnitude higher than those often found in Europe, North America and other Asian countries. Pollutants were expected to be mainly from local sources, including factories, motor vehicle emissions and civil construction. Non-local sources such as moderate- and long-range transport of sea salt also contributed to pollution levels in fog events as indicated by back trajectory analysis. The pH of the fog water collected during the monitoring period varied from 4.68 to 6.58; acidic fogs represented about 30.8% of the total fog events during this period. The fog water was characterized by high concentrations of SO42- (20.0% of measured TIC), NO3- (17.1%), NH4+ (28.3%) and Ca 2+ (14.4%). SO42- and NO3-, the main precursors of fog acidity, were related to burning fossil fuels and vehicle emissions, respectively. NH4+, originating from the scavenging of gaseous ammonia and particulate ammonium nitrate and ammonium sulfate, and Ca 2+, originating from the scavenging of coarse particles, acted as acid neutralizers and were the main cause for the relatively high pH of fogs in Shanghai. The ratio of ( SO42- + NO3-)/( NH4+ + Ca 2+) was lower than 1, indicating the alkaline nature of the fog water. A high ratio of NO3-/ SO42- and low ratio of HCOO -/CH 3COO - were consistent with large contributions from vehicular emissions that produce severe air pollution in megacities.

  9. Water Treatment Technology - Chemistry/Bacteriology.

    ERIC Educational Resources Information Center

    Ross-Harrington, Melinda; Kincaid, G. David

    One of twelve water treatment technology units, this student manual on chemistry/bacteriology provides instructional materials for twelve competencies. (The twelve units are designed for a continuing education training course for public water supply operators.) The competencies focus on the following areas: waterborne diseases, water sampling…

  10. Water Treatment Technology - Chemistry/Bacteriology.

    ERIC Educational Resources Information Center

    Ross-Harrington, Melinda; Kincaid, G. David

    One of twelve water treatment technology units, this student manual on chemistry/bacteriology provides instructional materials for twelve competencies. (The twelve units are designed for a continuing education training course for public water supply operators.) The competencies focus on the following areas: waterborne diseases, water sampling…

  11. Enhanced Accident Tolerant LWR Fuels: Metrics Development

    SciTech Connect

    Shannon Bragg-Sitton; Lori Braase; Rose Montgomery; Chris Stanek; Robert Montgomery; Lance Snead; Larry Ott; Mike Billone

    2013-09-01

    The Department of Energy (DOE) Fuel Cycle Research and Development (FCRD) Advanced Fuels Campaign (AFC) is conducting research and development on enhanced Accident Tolerant Fuels (ATF) for light water reactors (LWRs). This mission emphasizes the development of novel fuel and cladding concepts to replace the current zirconium alloy-uranium dioxide (UO2) fuel system. The overall mission of the ATF research is to develop advanced fuels/cladding with improved performance, reliability and safety characteristics during normal operations and accident conditions, while minimizing waste generation. The initial effort will focus on implementation in operating reactors or reactors with design certifications. To initiate the development of quantitative metrics for ATR, a LWR Enhanced Accident Tolerant Fuels Metrics Development Workshop was held in October 2012 in Germantown, MD. This paper summarizes the outcome of that workshop and the current status of metrics development for LWR ATF.

  12. Water Chemistry of Ephemeral Streams

    Treesearch

    J.L. Michael; W.P. Fowler; H.L. Gibbs; J.B. Fischer

    1994-01-01

    Four individual, but related, studies are currently being conducted to determine the effects of clearcut and seed tree reproduction cutting methods on stream chemistry, sedimentation, and bedload movement by monitoring herbicide and nutrient movement in stemflow, overland flow, streamflow, and zonal subsurface flow. Sediment movement is being quantified for...

  13. Water chemistry affects catfish susceptibility to columnaris

    USDA-ARS?s Scientific Manuscript database

    While columnaris disease has been well-studied, little is known about how specific water chemistries can affect attachment. Recent studies in our labs offer new insight on this subject. Well waters from the USDA/ARS Stuttgart National Aquaculture Research Center (SNARC; Stuttgart, Arkansas) and fr...

  14. Radiation Damage Assessment in the Reactor Pressure Vessel of the Integral Inherently Safe Light Water Reactor (I2S-LWR)

    NASA Astrophysics Data System (ADS)

    Flaspoehler, Timothy; Petrovic, Bojan

    2016-02-01

    One of the major limiting factors to nuclear reactors lifetime is the radiation-induced material damage in the Reactor Pressure Vessel (RPV). While older reactors were designed assuming a 40-year operating lifetime, new reactor designs are expected to have lifetimes up to 100 years. For safe operation, the integrity of the RPV must be ensured against significant material property changes. In this work, typical neutron damage indicators are calculated in the RPV of the I2S-LWR (Integral Inherently Safe LWR) Power Plant, including DPA (displacements per atom) and fast neutron fluence (>1 MeV and >0.1MeV). I2S-LWR is a PWR of integral design, which means that its wider downcomer provides additional shielding to the vessel. However, its higher core power density and longer lifetime may offset this advantage. In order to accurately represent the neutron environment for RPV damage assessment, a detailed model based on the preliminary design specifications of the I2S-LWR was developed to be used in the MAVRIC (Monaco with Automated Variance Reduction using Importance Calculations) sequence of the Scale6.1 code package. MAVRIC uses the CADIS (Consistent Adjoint-Driven Importance Sampling) methodology to bias a fixed-source MC (Monte Carlo) simulation. To establish the upper limit of a bounding envelope, a flat-source distribution was used. For the low limit, a center-peaked source was generated using the KENO-VI criticality sequence assuming uniform fresh fuel core. Results based on the preliminary I2S-LWR model show that DPA rates and fast fluence rates are conservatively 75% lower than in typical PWRs being operated currently in the US.

  15. Modifications of water chemistry for pressurized water reactors

    SciTech Connect

    Fletcher, W.D.

    1987-01-01

    For commercial pressurized water reactors, the evolution of the water chemistry for both the reactor coolant systems (RCS) and the balance of plant (BOP) systems has been in concert with or responsive to the changes in specified materials and operating experience. Much of the early reactor coolant chemistry was identified within a program to develop the use of boric acid as a water soluble neutron absorber for chemical shim. Boric acid was selected as the absorber. The BOP steam and feedwater cycle chemistry was largely a translation from conventional low-pressure boiler water chemistry with specific changes to account for new materials in major components. Today's chemistry for the reactor and BOP systems has undergone significant changes since circa 1950. With advances in the design duty of the plant components and with a much better understanding of the mechanisms of corrosion of component materials, the water chemistry practices and methods of control are more successfully aimed at plant reliability than ever before. This paper presents a review of several important advances in water chemistry, as applied to both the RCS and the BOP and the basis for their adoption.

  16. MCNP LWR Core Generator

    SciTech Connect

    Fischer, Noah A.

    2012-08-14

    The reactor core input generator allows for MCNP input files to be tailored to design specifications and generated in seconds. Full reactor models can now easily be created by specifying a small set of parameters and generating an MCNP input for a full reactor core. Axial zoning of the core will allow for density variation in the fuel and moderator, with pin-by-pin fidelity, so that BWR cores can more accurately be modeled. LWR core work in progress: (1) Reflectivity option for specifying 1/4, 1/2, or full core simulation; (2) Axial zoning for moderator densities that vary with height; (3) Generating multiple types of assemblies for different fuel enrichments; and (4) Parameters for specifying BWR box walls. Fuel pin work in progress: (1) Radial and azimuthal zoning for generating further unique materials in fuel rods; (2) Options for specifying different types of fuel for MOX or multiple burn assemblies; (3) Additional options for replacing fuel rods with burnable poison rods; and (4) Control rod/blade modeling.

  17. Enhanced water management using bromine chemistry

    SciTech Connect

    Sergent, R.H.

    1986-01-01

    This paper focuses on bromine chemistry and some of its unique properties, with regard to providing solutions to new and changing problems. Bromine Chemistry offers many unique properties for enhancing a water management program. Regardless of the method used to generate a residual, hypobromous acid delivers faster kill rates than an equimolar concentration of hypochlorous acid at an elevated pH or in the presence of ammonia or nitrogenous materials. In addition, the faster degradation of most bromine compounds relative to their chlorinated analogs increases the environmental acceptability of most brominated effluents relative to chlorination. Based on these advantages, the application of bromine chemistry to water treatment requirements has moved out of the speculative research phase and has moved into the sphere of a practical, commercial reality.

  18. Chemistry of saline-water chlorination

    SciTech Connect

    Haag, W.R.

    1981-06-01

    Vast quantities of natural waters are used by power plants for cooling purposes. This water is chlorinated to prevent slime build-up inside the cooling pipes, is circulated through the cooling system, and eventually discharged back into the water body. In order to assess the environmental impact of water chlorination, it is necessary to know what chemical compounds are produced and discharged into the receiving waters. To attack this problem, a review of the present state of knowledge of natural water chlorination chemistry was performed, and some experimental work explained the results of previous workers by showing that chlorine losses at very high doses in seawater are simply the result of chlorate and bromate formation which, however, is negligible at normal doses. The most important chlorine-produced oxidants, along with the relevant chemical reactions, were chosen as a basis for a kinetic model of saline water chlorination chemistry. Kinetic data were compiled in a computer program which simultaneously solves 24 differential equations, one for each species modelled. Estimates were made for the unknown rate constants. A purely predictive model was not possible due to the great variability in the organic demand; however, the model is applicable under a broad variety of conditions (except sunlight), and it provides a reasonably good description of a halamine chemistry under environmental conditions.

  19. Tularosa Basin Play Fairway Analysis: Water Chemistry

    DOE Data Explorer

    Adam Brandt

    2015-12-15

    This shapefile contains 409 well data points on Tularosa Basin Water Chemistry, each of which have a location (UTM), temperature, quartz and Potassium/Magnesium geothermometer; as well as concentrations of chemicals like Mn, Fe, Ba, Sr, Cs, Rb, As, NH4, HCO3, SO4, F, Cl, B, SiO2, Mg, Ca, K, Na, and Li.

  20. Control of degradation of spent LWR (light-water reactor) fuel during dry storage in an inert atmosphere

    SciTech Connect

    Cunningham, M.E.; Simonen, E.P.; Allemann, R.T.; Levy, I.S.; Hazelton, R.F.

    1987-10-01

    Dry storage of Zircaloy-clad spent fuel in inert gas (referred to as inerted dry storage or IDS) is being developed as an alternative to water pool storage of spent fuel. The objectives of the activities described in this report are to identify potential Zircaloy degradation mechanisms and evaluate their applicability to cladding breach during IDS, develop models of the dominant Zircaloy degradation mechanisms, and recommend cladding temperature limits during IDS to control Zircaloy degradation. The principal potential Zircaloy cladding breach mechanisms during IDS have been identified as creep rupture, stress corrosion cracking (SCC), and delayed hydride cracking (DHC). Creep rupture is concluded to be the primary cladding breach mechanism during IDS. Deformation and fracture maps based on creep rupture were developed for Zircaloy. These maps were then used as the basis for developing spent fuel cladding temperature limits that would prevent cladding breach during a 40-year IDS period. The probability of cladding breach for spent fuel stored at the temperature limit is less than 0.5% per spent fuel rod. 52 refs., 7 figs., 1 tab.

  1. Uniform corrosion of FeCrAl alloys in LWR coolant environments

    SciTech Connect

    Terrani, K. A.; Pint, B. A.; Kim, Y. -J.; Unocic, K. A.; Yang, Y.; Silva, C. M.; Meyer, III, H. M.; Rebak, R. B.

    2016-06-29

    The corrosion behavior of commercial and model FeCrAl alloys and type 310 stainless steel was examined by autoclave tests and compared to Zircaloy-4, the reference cladding materials in light water reactors. The corrosion studies were carried out in three distinct water chemistry environments found in pressurized and boiling water reactor primary coolant loop conditions for up to one year. The structure and morphology of the oxides formed on the surface of these alloys was consistent with thermodynamic predictions. Spinel-type oxides were found to be present after hydrogen water chemistry exposures, while the oxygenated water tests resulted in the formation of very thin and protective hematite-type oxides. Unlike the alloys exposed to oxygenated water tests, the alloys tested in hydrogen water chemistry conditions experienced mass loss as a function of time. This mass loss was the result of net sum of mass gain due to parabolic oxidation and mass loss due to dissolution that also exhibits parabolic kinetics. Finally, the maximum thickness loss after one year of LWR water corrosion in the absence of irradiation was ~2 μm, which is inconsequential for a ~300–500 μm thick cladding.

  2. Uniform corrosion of FeCrAl alloys in LWR coolant environments

    DOE PAGES

    Terrani, K. A.; Pint, B. A.; Kim, Y. -J.; ...

    2016-06-29

    The corrosion behavior of commercial and model FeCrAl alloys and type 310 stainless steel was examined by autoclave tests and compared to Zircaloy-4, the reference cladding materials in light water reactors. The corrosion studies were carried out in three distinct water chemistry environments found in pressurized and boiling water reactor primary coolant loop conditions for up to one year. The structure and morphology of the oxides formed on the surface of these alloys was consistent with thermodynamic predictions. Spinel-type oxides were found to be present after hydrogen water chemistry exposures, while the oxygenated water tests resulted in the formation ofmore » very thin and protective hematite-type oxides. Unlike the alloys exposed to oxygenated water tests, the alloys tested in hydrogen water chemistry conditions experienced mass loss as a function of time. This mass loss was the result of net sum of mass gain due to parabolic oxidation and mass loss due to dissolution that also exhibits parabolic kinetics. Finally, the maximum thickness loss after one year of LWR water corrosion in the absence of irradiation was ~2 μm, which is inconsequential for a ~300–500 μm thick cladding.« less

  3. Uniform corrosion of FeCrAl alloys in LWR coolant environments

    SciTech Connect

    Terrani, K. A.; Pint, B. A.; Kim, Y. -J.; Unocic, K. A.; Yang, Y.; Silva, C. M.; Meyer, III, H. M.; Rebak, R. B.

    2016-06-29

    The corrosion behavior of commercial and model FeCrAl alloys and type 310 stainless steel was examined by autoclave tests and compared to Zircaloy-4, the reference cladding materials in light water reactors. The corrosion studies were carried out in three distinct water chemistry environments found in pressurized and boiling water reactor primary coolant loop conditions for up to one year. The structure and morphology of the oxides formed on the surface of these alloys was consistent with thermodynamic predictions. Spinel-type oxides were found to be present after hydrogen water chemistry exposures, while the oxygenated water tests resulted in the formation of very thin and protective hematite-type oxides. Unlike the alloys exposed to oxygenated water tests, the alloys tested in hydrogen water chemistry conditions experienced mass loss as a function of time. This mass loss was the result of net sum of mass gain due to parabolic oxidation and mass loss due to dissolution that also exhibits parabolic kinetics. Finally, the maximum thickness loss after one year of LWR water corrosion in the absence of irradiation was ~2 μm, which is inconsequential for a ~300–500 μm thick cladding.

  4. Uniform corrosion of FeCrAl alloys in LWR coolant environments

    NASA Astrophysics Data System (ADS)

    Terrani, K. A.; Pint, B. A.; Kim, Y.-J.; Unocic, K. A.; Yang, Y.; Silva, C. M.; Meyer, H. M.; Rebak, R. B.

    2016-10-01

    The corrosion behavior of commercial and model FeCrAl alloys and type 310 stainless steel was examined by autoclave tests and compared to Zircaloy-4, the reference cladding materials in light water reactors. The corrosion studies were carried out in three distinct water chemistry environments found in pressurized and boiling water reactor primary coolant loop conditions for up to one year. The structure and morphology of the oxides formed on the surface of these alloys was consistent with thermodynamic predictions. Spinel-type oxides were found to be present after hydrogen water chemistry exposures, while the oxygenated water tests resulted in the formation of very thin and protective hematite-type oxides. Unlike the alloys exposed to oxygenated water tests, the alloys tested in hydrogen water chemistry conditions experienced mass loss as a function of time. This mass loss was the result of net sum of mass gain due to parabolic oxidation and mass loss due to dissolution that also exhibits parabolic kinetics. The maximum thickness loss after one year of LWR water corrosion in the absence of irradiation was ∼2 μm, which is inconsequential for a ∼300-500 μm thick cladding.

  5. Hydrogen Water Chemistry Technology in Boiling Water Reactors

    SciTech Connect

    Lin, Chien C

    2000-04-15

    Modification of coolant chemistry by feedwater hydrogen addition in boiling water reactors (BWRs), generally called hydrogen water chemistry (HWC), is a viable option to mitigate the intergranular stress corrosion cracking problems for operating BWRs. Some fundamentals in HWC technologies as known today are reviewed. Several full-scale HWC test results are analyzed, and the roles that hydrogen plays in HWC technology are identified and quantitatively evaluated. Some deficiencies in water radiolysis modeling for BWR applications under HWC conditions and the impact of {sup 16}N radiation field increase in the main steam line are also discussed.

  6. Design Features of the SMART Water Chemistry

    SciTech Connect

    Byung Seon Choi; Seong Hoon Kim; Juhyeon Yoon; Doo Jeong Lee; Yoon Yeong Bae; Sung Kyun Zee

    2004-07-01

    The design features for the primary water chemistry for the SMART are introduced from the viewpoint of the system characteristics and the chemical design concept. The most essential differences in water chemistry between the commercially operating PWRs and SMART are characterized by the presence of boron in the water and the operating mode of the purification system. SMART is a soluble boron free reactor, and the ammonia is used as a pH reagent. The material for SMART steam generator is also different from the standard material of the commercially operating PWRs: titanium alloy for the steam generator tubes. In SMART hydrogen gas which suppresses a generation of oxidizing species by the radiolysis processes in the reactors is not added to the primary coolant, but is normally generated from the radiolysis of the ammonia as the coolant passes through the core. Ammonia is added once per shift because SMART reactor has no letdown and charging system during power operation. Because of these competing processes, the concentrations of hydrogen, nitrogen and ammonia in the primary coolant are in equilibrium, which depend on the decomposition and/or combination rate of the ammonia. The level of permissible oxygen concentration in the primary coolant can be ensured by both suppression of the water radiolysis through maintaining a high enough hydrogen concentration in the primary coolant and by a restriction of the oxygen ingress into the primary coolant with the makeup water. The ammonia chemistry in SMART reactor eliminates the need for hydrogen injection for the control of the dissolved oxygen in the primary coolant because of spontaneous generation of hydrogen and nitrogen produced by the reaction of the ammonia decomposition. (authors)

  7. LWR improvement in EUV resist process

    NASA Astrophysics Data System (ADS)

    Koh, Chawon; Kim, Hyun-Woo; Kim, Sumin; Na, Hai-Sub; Park, Chang-Min; Park, Cheolhong; Cho, Kyoung-Yong

    2011-04-01

    Extreme ultraviolet lithography (EUVL) is the most effective way to print sub-30 nm features. The roughness of both the resist sidewall (line width roughness [LWR]) and resist top must be overcome soon for EUVL to be implemented. Currently, LWR can vary by about 1 nm according to the recipe used. We have characterized two promising techniques to improve LWR, an EUV rinse/TBAH process and an implant process, and demonstrated their efficacy. After cleaning inspection (ACI), LWR was improved with both the rinse and implant processes. After development inspection (ADI), LWR improved (0.12 nm, 2.4%) and ACI LWR improved (0.1 nm, 2.0% improvement) after using the EUV rinse process. ADI and ACI LWR improvement (0.45 nm, 9.1%, and 0.3 nm, 6.9%, respectively) was demonstrated with the EUV rinse/TBAH process. ADI LWR improvement (0.5 nm, 8.1%) and ACI LWR improvement (-0.5 nm, -16.9%) were characterized with the implant process. Critical dimension (CD) showed similar changes through pitch after the EUV rinse or TBAH process, but the degree of change depended on the initial pattern size giving CD difference of 2 nm between 30 nm HP and 50 nm HP after the implant process. For this technique, the dependence of CD change on pattern size must be minimized. Further extensive studies with rinse or implant are strongly encouraged for continued LWR improvement and real process implementation in EUVL. Demonstrating <2.2 nm LWR after pattern transfer is important in EUVL and needs to be pursued using various technical approaches. Initial resist LWR is important in assessing LWR improvements with additional process techniques. An initial EUV LWR < ~5.0 nm is required to properly assess the validity of the technique. Further study is required to improve ADI LWR and maintain better LWR after etch with advanced EUV rinse materials. Defects also need to be confirmed following the EUV rinse and TBAH developer. Further developing the implant process should focus on LWR improvement at low

  8. Acidic deposition and surface water chemistry

    NASA Astrophysics Data System (ADS)

    Church, M. R.

    A pair of back-to-back (morning and afternoon) hydrology sessions, held December 10, 1987, at the AGU Fall Meeting in San Francisco, Calif., covered “Predicting the Effects of Acidic Deposition on Surface Water Chemistry.” The combined sessions included four invited papers, 12 contributed papers, and a panel discussion at its conclusion. The gathering dealt with questions on a variety of aspects of modeling the effects of acidic deposition on surface water chemistry.Contributed papers included discussions on the representation of processes in models as well as limiting assumptions in model application (V. S. Tripathi et al., Oak Ridge National Laboratory, Oak Ridge, Tenn., and E. C. Krug, Illinois State Water Survey, Champaign), along with problems in estimating depositional inputs to catchments and thus inputs to be used in the simulation of catchment response (M. M. Reddy et al., U.S. Geological Survey, Lakewood, Colo.; and E. A. McBean, University of Waterloo, Waterloo, Canada). L. A. Baker et al. (University of Minnesota, Minneapolis) dealt with the problem of modeling seepage lake systems, an exceedingly important portion of the aquatic resources in Florida and parts of the upper U.S. Midwest. J. A. Hau and Y. Eckstein (Kent State University, Kent, Ohio) considered equilibrium modeling of two northern Ohio watersheds that receive very different loads of acidic deposition but are highly similar in other respects.

  9. Research, Development and Demonstration (RD&D) Needs for Light Water Reactor (LWR) Technologies A Report to the Reactor Technology Subcommittee of the Nuclear Energy Advisory Committee (NEAC) Office of Nuclear Energy U.S. Department of Energy

    SciTech Connect

    McCarthy, Kathryn A.; Adams, Bradley J.

    2016-04-01

    The LWR RD&D Working Group developed a detailed list of RD&D suggestions and recommendations, which are provided in Appendix D. The Working Group then undertook a systematic ranking process, described in Appendix E. The results of the ranking process are not meant to be a strict set of priorities, but rather should provide insight into how the items generally ranked within the Working Group. Future discussions and investigation into these items could provide information that would support a change in these priorities or in their emphasis. The results of this prioritization are provided below. Note that in general, many RD&D ideas are applicable to both new Advanced Light Water Reactor (ALWR) plants and currently operating plants.

  10. Uranium mononitride as a potential commercial LWR fuel

    SciTech Connect

    Xu, P.; Yan, J.; Lahoda, E. J.; Ray, S.

    2012-07-01

    This paper evaluated uranium mononitride (UN) as a potential replacement for 5% enriched UO{sub 2} fuel in Generation III and III+ commercial light water reactors (LWRs). Significant improvement in LWR performance depends on developing and implementing changes in the nuclear fuel used in these reactors. Compared to UO{sub 2}, UN offers several advantages such as higher uranium loading and better thermal conductivity. In this paper, the thermal safety margin of UN was evaluated at both normal and accident conditions using a readily available coupled CFD model developed for the US DOE CASL program. One of the prime technical challenges in utilization of UN as LWR fuel is the water compatibility because pure phase UN is not stable in water at 350 deg. C. The water corrosion resistance of UN and the corrosion mechanism were reviewed and mitigation methods were proposed. (authors)

  11. Montane wetland water chemistry, Uinta Mountains, Utah

    NASA Astrophysics Data System (ADS)

    Severson, K. S.; Matyjasik, M.; Ford, R. L.; Hernandez, M. W.; Welsh, S. B.; Summers, S.; Bartholomew, L. M.

    2009-12-01

    This study attempts to determine the relationship between surface and groundwater chemistry and wetland characteristics within the Reader Lakes watershed, Uinta Mountains. The dominant rock type in the study area is quartz sandstone of the Hades Pass formation, Unita Mountain Group (Middle Proterozoic). Minor amounts of interbedded arkose and illite-bearing shale are also present. Water chemistry data have been collected from more than one hundred locations during the 2008 and 2009 summer seasons. The Reader Creek watershed is approximately 9.8 km long and about 3.5 km wide in the central portion of the basin. Direct precipitation is the primary source of groundwater recharge and the area is typically covered by snow from November until May. Four distinct wetland complexes, designated as the upper, middle, lower and the sloping fen, constitute the major wetland environments in the study area. The chemistry of the melt water from the high-elevation snowfield is affected by weathering of incorporated atmospheric dust and surface rocks. Total dissolved solids in both years were between 7 and 9 mg/L. Major anions include HCO3 (averaging 4.0 mg/L), SO4 (1.3 mg/L), NO3 (0.9 mg/L), Cl (0.8 mg/L), F (0.07 mg/L), PO4 (0.03 mg/L), and Br(0.015 mg/L). Major cations include Na (1.1 mg/L), Ca (1.0 mg/L), K (0.28 mg/L), and Mg (0.15 mg/L). Groundwater concentrations in the lower meadow, as measured in piezomters, are distinctly different, with the following maximum concentrations of anions: HCO3 (36.7 mg/L), SO4 (5.0 mg/L), Cl (3.4 mg/L), NO3 (0.9 mg/L), PO4 (0.28 mg/L), F (0.23 mg/L), Br (0.12 mg/L), and cations: Ca (22 mg/L), Na (4.6 mg/L), Mg (3.4 mg/L), and K (1.8 mg/L)- with a maximum value of 83 mg/L for total dissolved solids. Waters in Reader Creek, the main trunk channel, are typically sodium-potassium and sodium -potassium bicarbonate, with some calcium-bicarbonate, mostly in the middle part of the watershed. Groundwater from springs is sodium-potassium in the upper

  12. Water oxidation chemistry of photosystem II.

    PubMed Central

    Vrettos, John S; Brudvig, Gary W

    2002-01-01

    The O(2)-evolving complex of photosystem II catalyses the light-driven four-electron oxidation of water to dioxygen in photosynthesis. In this article, the steps leading to photosynthetic O(2) evolution are discussed. Emphasis is given to the proton-coupled electron-transfer steps involved in oxidation of the manganese cluster by oxidized tyrosine Z (Y(*)(Z)), the function of Ca(2+) and the mechanism by which water is activated for formation of an O-O bond. Based on a consideration of the biophysical studies of photosystem II and inorganic manganese model chemistry, a mechanism for photosynthetic O(2) evolution is presented in which the O-O bond-forming step occurs via nucleophilic attack on an electron-deficient Mn(V)=O species by a calcium-bound water molecule. The proposed mechanism includes specific roles for the tetranuclear manganese cluster, calcium, chloride, Y(Z) and His190 of the D1 polypeptide. Recent studies of the ion selectivity of the calcium site in the O(2)-evolving complex and of a functional inorganic manganese model system that test key aspects of this mechanism are also discussed. PMID:12437878

  13. Improving the safety of LWR power plants. Final report

    SciTech Connect

    Not Available

    1980-04-01

    This report documents the results of the Study to identify current, potential research issues and efforts for improving the safety of Light Water Reactor (LWR) power plants. This final report describes the work accomplished, the results obtained, the problem areas, and the recommended solutions. Specifically, for each of the issues identified in this report for improving the safety of LWR power plants, a description is provided in detail of the safety significance, the current status (including information sources, status of technical knowledge, problem solution and current activities), and the suggestions for further research and development. Further, the issues are ranked for action into high, medium, and low priority with respect to primarily (a) improved safety (e.g. potential reduction in public risk and occupational exposure), and secondly (b) reduction in safety-related costs (improving or maintaining level of safety with simpler systems or in a more cost-effective manner).

  14. Bottled water, spas, and early years of water chemistry

    USGS Publications Warehouse

    Back, William; Landa, Edward R.; Meeks, Lisa

    1995-01-01

    Although hot springs have been used and enjoyed for thousands of years, it was not until the late 1700s that they changed the course of world civilization by being the motivation for development of the science of chemistry. The pioneers of chemistry such as Priestley, Cavendish, Lavoisier, and Henry were working to identify and generate gases, in part, to determine their role in carbonated beverages. In the 18th century, spas in America were developed to follow the traditional activities of popular European spas. However, they were to become a dominant political and economic force in American history on three major points: (1) By far the most important was to provide a place for the leaders of individual colonies to meet and discuss the need for separation from England and the necessity for the Revolutionary War; (2) the westward expansion of the United States was facilitated by the presence of hot springs in many locations that provided the economic justification for railroads and settlement; and (3) the desire for the preservation of hot springs led to the establishment of the National Park Service. Although mineral springs have maintained their therapeutic credibility in many parts of the world, they have not done so in the United States. We suggest that the American decline was prompted by: (1) the establishment of The Johns Hopkins School of Medicine in 1893; (2) enactment of the Pure Food and Drug Act of 1907; and (3) the remarkable achievement of providing safe water supplies for American cities by the end of the 1920s. The current expanding market for bottled water is based in part on bottled water being an alternative beverage Ito alcohol and sweetened drinks and the inconsistent palatability and perceived health hazards of some tap waters.

  15. Automated Water Chemistry Control at University of Virginia Pools.

    ERIC Educational Resources Information Center

    Krone, Dan

    1997-01-01

    Describes the technologically advanced aquatic and fitness center at the University of Virginia. Discusses the imprecise water chemistry control at the former facility and its intensive monitoring requirements. Details the new chemistry control standards initiated in the new center, which ensure constant chlorine and pH levels. (RJM)

  16. Automated Water Chemistry Control at University of Virginia Pools.

    ERIC Educational Resources Information Center

    Krone, Dan

    1997-01-01

    Describes the technologically advanced aquatic and fitness center at the University of Virginia. Discusses the imprecise water chemistry control at the former facility and its intensive monitoring requirements. Details the new chemistry control standards initiated in the new center, which ensure constant chlorine and pH levels. (RJM)

  17. Integrity of neutron-absorbing components of LWR fuel systems

    SciTech Connect

    Bailey, W.J.; Berting, F.M.

    1991-03-01

    A study of the integrity and behavior of neutron-absorbing components of light-water (LWR) fuel systems was performed by Pacific Northwest Laboratory (PNL) and sponsored by the US Department of Energy (DOE). The components studies include control blades (cruciforms) for boiling-water reactors (BWRs) and rod cluster control assemblies for pressurized-water reactors (PWRs). The results of this study can be useful for understanding the degradation of neutron-absorbing components and for waste management planning and repository design. The report includes examples of the types of degradation, damage, or failures that have been encountered. Conclusions and recommendations are listed. 84 refs.

  18. Simulated Fission Gas Behavior in Silicide Fuel at LWR Conditions

    SciTech Connect

    Miao, Yinbin; Mo, Kun; Yacout, Abdellatif; Harp, Jason

    2016-09-15

    As a promising candidate for the accident tolerant fuel (ATF) used in light water reactors (LWRs), the fuel performance of uranium silicide (U3Si2) at LWR conditions needs to be well-understood. However, existing experimental post-irradiation examination (PIE) data are limited to the research reactor conditions, which involve lower fuel temperature compared to LWR conditions. This lack of appropriate experimental data significantly affects the development of fuel performance codes that can precisely predict the microstructure evolution and property degradation at LWR conditions, and therefore evaluate the qualification of U3Si2 as an AFT for LWRs. Considering the high cost, long timescale, and restrictive access of the in-pile irradiation experiments, this study aims to utilize ion irradiation to simulate the inpile behavior of the U3Si2 fuel. Both in situ TEM ion irradiation and ex situ high-energy ATLAS ion irradiation experiments were employed to simulate different types of microstructure modifications in U3Si2. Multiple PIE techniques were used or will be used to quantitatively analyze the microstructure evolution induced by ion irradiation so as to provide valuable reference for the development of fuel performance code prior to the availability of the in-pile irradiation data.

  19. Microstructure and hydrothermal corrosion behavior of NITE-SiC with various sintering additives in LWR coolant environments

    DOE PAGES

    Parish, Chad M.; Terrani, Kurt A.; Kim, Young -Jin; ...

    2016-11-28

    Nano-infiltration and transient eutectic phase (NITE) sintering was developed for fabrication of nuclear grade SiC composites. We produced monolithic SiC ceramics using NITE sintering, as candidates for accident-tolerant fuels in light-water reactors (LWRs). In this work, we exposed three different NITE chemistries (yttria-alumina [YA], ceria-zirconia-alumina [CZA], and yttria-zirconia-alumina [YZA]) to autoclave conditions simulating LWR coolant loops. The YZA was most corrosion resistant, followed by CZA, with YA being worst. High-resolution elemental analysis using scanning transmission electron microscopy (STEM) X-ray mapping combined with multivariate statistical analysis (MVSA) datamining helped explain the differences in corrosion. YA-NITE lost all Al from the corrodedmore » region and the ytttria reformed into blocky precipitates. The CZA material lost all Al from the corroded area, and the YZA – which suffered the least corrosion –retained some Al in the corroded region. Lastly, the results indicate that the YZA-NITE SiC is most resistant to hydrothermal corrosion in the LWR environment.« less

  20. Microstructure and hydrothermal corrosion behavior of NITE-SiC with various sintering additives in LWR coolant environments

    SciTech Connect

    Parish, Chad M.; Terrani, Kurt A.; Kim, Young -Jin; Koyanagi, Takaaki; Katoh, Yutai

    2016-11-28

    Nano-infiltration and transient eutectic phase (NITE) sintering was developed for fabrication of nuclear grade SiC composites. We produced monolithic SiC ceramics using NITE sintering, as candidates for accident-tolerant fuels in light-water reactors (LWRs). In this work, we exposed three different NITE chemistries (yttria-alumina [YA], ceria-zirconia-alumina [CZA], and yttria-zirconia-alumina [YZA]) to autoclave conditions simulating LWR coolant loops. The YZA was most corrosion resistant, followed by CZA, with YA being worst. High-resolution elemental analysis using scanning transmission electron microscopy (STEM) X-ray mapping combined with multivariate statistical analysis (MVSA) datamining helped explain the differences in corrosion. YA-NITE lost all Al from the corroded region and the ytttria reformed into blocky precipitates. The CZA material lost all Al from the corroded area, and the YZA – which suffered the least corrosion –retained some Al in the corroded region. Lastly, the results indicate that the YZA-NITE SiC is most resistant to hydrothermal corrosion in the LWR environment.

  1. Status report on assessment of environmentally assisted fatigue for LWR extended service conditions

    SciTech Connect

    Mohanty, S.; Soppet, W. K.; Majumdar, S.; Natesan, K.

    2014-07-09

    This report provides an update on an earlier assessment of environmentally assisted fatigue for light water reactor (LWR) materials under extended service conditions. This report is a deliverable in September 2013, under the work package for environmentally assisted fatigue in the Light Water Reactor Sustainability (LWRS) program. The overall objective of this LWRS project is to assess the degradation by environmentally assisted cracking/fatigue of LWR materials, such as various alloy base metals and their welds used in reactor coolant system piping. This effort is to support the U.S. Department of Energy LWRS program for developing tools to predict the aging/failure mechanism and to correspondingly predict the remaining life of LWR components for anticipated 60-80 year operation.

  2. Investigation of valve failure problems in LWR power plants

    SciTech Connect

    1980-04-01

    An analysis of component failures from information in the computerized Nuclear Safety Information Center (NSIC) data bank shows that for both PWR and BWR plants the component category most responsible for approximately 19.3% of light water reactor (LWR) power plant shutdowns. This investigation by Burns and Roe, Inc. shows that the greatest cause of shutdowns in LWRs due to valve failures is leakage from valve stem packing. Both BWR plants and PWR plants have stem leakage problems (BWRs, 21% and PWRs, 34%).

  3. Contribution of water chemistry and fish condition to otolith chemistry: comparisons across salinity environments.

    PubMed

    Izzo, C; Doubleday, Z A; Schultz, A G; Woodcock, S H; Gillanders, B M

    2015-06-01

    This study quantified the per cent contribution of water chemistry to otolith chemistry using enriched stable isotopes of strontium ((86) Sr) and barium ((137) Ba). Euryhaline barramundi Lates calcarifer, were reared in marine (salinity 40), estuarine (salinity 20) and freshwater (salinity 0) under different temperature treatments. To calculate the contribution of water to Sr and Ba in otoliths, enriched isotopes in the tank water and otoliths were quantified and fitted to isotope mixing models. Fulton's K and RNA:DNA were also measured to explore the influence of fish condition on sources of element uptake. Water was the predominant source of otolith Sr (between 65 and 99%) and Ba (between 64 and 89%) in all treatments, but contributions varied with temperature (for Ba), or interactively with temperature and salinity (for Sr). Fish condition indices were affected independently by the experimental rearing conditions, as RNA:DNA differed significantly among salinity treatments and Fulton's K was significantly different between temperature treatments. Regression analyses did not detect relations between fish condition and per cent contribution values. General linear models indicated that contributions from water chemistry to otolith chemistry were primarily influenced by temperature and secondly by fish condition, with a relatively minor influence of salinity. These results further the understanding of factors that affect otolith element uptake, highlighting the necessity to consider the influence of environment and fish condition when interpreting otolith element data to reconstruct the environmental histories of fish.

  4. Water chemistry: fifty years of change and progress.

    PubMed

    Brezonik, Patrick L; Arnold, William A

    2012-06-05

    Water chemistry evolved from early foundations in several related disciplines. Although it is difficult to associate a precise date to its founding, several events support the argument that the field as we know it today developed in the mid-20th century--at the dawn of the "environmental era"--that is, ∼1960. The field in its modern incarnation thus is about 50 years old. In celebration of this half-centenary, we examine here the origins of water chemistry, how the field has changed over the past 50 years, and the principal driving forces for change, focusing on both the "practice" of water chemistry and ways that teaching the subject has evolved.

  5. Par Pond Fish, Water, and Sediment Chemistry

    SciTech Connect

    Paller, M.H.; Wike, L.D.

    1996-06-01

    The objectives of this report are to describe the Par Pond fish community and the impact of the drawdown and refill on the community, describe contaminant levels in Par Pond fish, sediments, and water and indicate how contaminant concentrations and distributions were affected by the drawdown and refill, and predict possible effects of future water level fluctuations in Par Pond.

  6. Environmental Chemistry: Air and Water Pollution.

    ERIC Educational Resources Information Center

    Stoker, H. Stephen; Seager, Spencer L.

    This is a book about air and water pollution whose chapters cover the topics of air pollution--general considerations, carbon monoxide, oxides of nitrogen, hydrocarbons and photochemical oxidants, sulfur oxides, particulates, temperature inversions and the greenhouse effect; and water pollution--general considerations, mercury, lead, detergents,…

  7. Environmental Chemistry: Air and Water Pollution.

    ERIC Educational Resources Information Center

    Stoker, H. Stephen; Seager, Spencer L.

    This is a book about air and water pollution whose chapters cover the topics of air pollution--general considerations, carbon monoxide, oxides of nitrogen, hydrocarbons and photochemical oxidants, sulfur oxides, particulates, temperature inversions and the greenhouse effect; and water pollution--general considerations, mercury, lead, detergents,…

  8. Clean Air Markets - Monitoring Surface Water Chemistry

    EPA Pesticide Factsheets

    Learn about how EPA uses Long Term Monitoring (LTM) and Temporily Integrated Monitoring of Ecosystems (TIME) to track the effect of the Clean Air Act Amendments on acidity of surface waters in the eastern U.S.

  9. Hydrological Controls on Water Chemistry that Supports Freshwater Mussel Populations

    NASA Astrophysics Data System (ADS)

    Prestegaard, K. L.

    2012-12-01

    Native freshwater mussel species ranges and population sizes have been declining throughout N. America. Due to their sedentary nature, adult mussels are vulnerable to both local habitat changes (often associated with land-use changes, contaminants, and biological invaders) and to climate changes that can alter river flow regimes, bed stability, and water chemistry. The purpose of this study is to examine the relationship between water chemistry and hydrological events in rivers that support native mussel populations. USGS ion concentration and water quality (pH, temperature, conductivity) data were used to calculate saturation indices for aragonite. For some sites, electrical conductivity was highly correlated with calcium and bicarbonate concentrations and could be used to estimate concentrations when ion chemistry was not measured. Continuous water quality data from datasondes could thus be used to evaluate saturation indices for aragonite on a daily basis for 10-15 year periods. For the Delaware River, which has relatively few carbonate rocks in its watershed, tributary aragonite saturation tended to reflect local geological conditions. The lower main stem of the river integrates the water chemistry of the basin and also responds to climatic conditions. The lower Delaware supports aragonite precipitation approximately 50 days per year, with considerable inter-annual variability. During most years, aragonite precipitation could occur during both the spring and late summer periods, but years with heavy spring rains rather than snowmelt shifts aragonite precipitation to late summer periods. In 2011 when several major tropical storms hit the Delaware basin, streamflow was too dilute for aragonite precipitation for most of the summer period. These data suggest that hydrological changes associated with climatic changes may influence the water chemistry and affect the suitability of some rivers as mussel habitat.

  10. Water chemistry and cardiovascular disease risk

    SciTech Connect

    Watson, A.P.; Zeighami, E.A.

    1985-01-01

    The evidence linking cardiovascular disease risk and water quality parameters was weighed and analyzed to identify major gaps in understanding reasons for the regional differences in cardiovascular disease mortality in the United States. Epidemiologic studies evaluating occupational and public health exposure to nitrates, carbon monoxide, carbon disulfide, fibrogenic dusts, heavy metals and trace elements, chlorides, and hydro- and fluorocarbons were analyzed. Intake of cholesterol, calcium, and magnesium from food items, cooking water enhancement, and drinking water were also appraised. Based on the current state of knowledge, it is our judgment that the drinking water characteristics of highest priority from the standpoint of cardiovascular disease risks are calcium/magnesium content and chlorine treatment. The potential importance of cadmium, lead, nitrate(s), and chloride/sodium concentrations also needs to be considered. We present working hypotheses to evaluate the role(s) of these parameters and a discussion of variables that should be considered in any study design addressing the association between cardiovascular disease risk and water quality. Important variables are sample size, biological endpoint events (mortality, incidence, clinical determination), population characteristics, drinking water parameters, and dietary intake estimates. 207 references, 6 figures, 17 tables.

  11. Water chemistry of Rocky Mountain Front Range aquatic ecosystems

    Treesearch

    Robert C. Musselman; Laura Hudnell; Mark W. Williams; Richard A. Sommerfeld

    1996-01-01

    A study of the water chemistry of Colorado Rocky Mountain Front Range alpine/subalpine lakes and streams in wilderness ecosystems was conducted during the summer of 1995 by the USDA Forest Service Arapaho and Roosevelt National Forests and Rocky Mountain Forest and Range Experiment Station, and the University of Colorado Institute of Alpine and Arctic Research. Data...

  12. The chemistry of salt-affected soils and waters

    USDA-ARS?s Scientific Manuscript database

    Knowledge of the chemistry of salt affected soils and waters is necessary for management of irrigation in arid and semi-arid regions. In this chapter we review the origin of salts in the landscape, the major chemical reactions necessary for prediction of the soil solution composition, and the use of...

  13. Tools for placing the radiological health hazard in perspective following a severe emergency at a light water reactor (LWR) or its spent fuel pool.

    PubMed

    McKenna, Thomas; Welter, Phillip Vilar; Callen, Jessica; Martincic, Rafael; Dodd, Brian; Kutkov, Vladimir

    2015-01-01

    Experience from past nuclear and radiological emergencies shows that placing the radiological health hazard in perspective and having a definition of "safe" are required in order to prevent members of the public, those responsible for protecting the public (i.e., decision makers), and others from taking inappropriate and damaging actions that are not justified based on the radiological health hazard. The principle concerns of the public during a severe nuclear power plant or spent fuel pool emergency are "Am I safe?" and "What should I do to be safe?" However, these questions have not been answered to the satisfaction of the public, despite various protective actions being implemented to ensure their safety. Instead, calculated doses or various measured quantities (e.g., ambient dose rate or radionuclide concentrations) are used to describe the situation to the public without placing them into perspective in terms of the possible radiological health hazard, or if they have, it has been done incorrectly. This has contributed to members of the public taking actions that do more harm than good in the belief that they are protecting themselves. Based on established international guidance, this paper provides a definition of "safe" for the radiological health hazard for use in nuclear or radiological emergencies and a system for putting the radiological health hazard in perspective for quantities most commonly measured after a release resulting from a severe emergency at a light water reactor or its spent fuel pool.

  14. Air and water stable ionic liquids in physical chemistry.

    PubMed

    Endres, Frank; Zein El Abedin, Sherif

    2006-05-14

    Ionic liquids are defined today as liquids which solely consist of cations and anions and which by definition must have a melting point of 100 degrees C or below. Originating from electrochemistry in AlCl(3) based liquids an enormous progress was made during the recent 10 years to synthesize ionic liquids that can be handled under ambient conditions, and today about 300 ionic liquids are already commercially available. Whereas the main interest is still focussed on organic and technical chemistry, various aspects of physical chemistry in ionic liquids are discussed now in literature. In this review article we give a short overview on physicochemical aspects of ionic liquids, such as physical properties of ionic liquids, nanoparticles, nanotubes, batteries, spectroscopy, thermodynamics and catalysis of/in ionic liquids. The focus is set on air and water stable ionic liquids as they will presumably dominate various fields of chemistry in future.

  15. Effect of material heat treatment on fatigue crack initiation in austenitic stainless steels in LWR environments.

    SciTech Connect

    Chopra, O. K.; Alexandreanu, B.; Shack, W. J.; Energy Technology

    2005-07-31

    The ASME Boiler and Pressure Vessel Code provides rules for the design of Class 1 components of nuclear power plants. Figures I-9.1 through I-9.6 of Appendix I to Section III of the Code specify design curves for applicable structural materials. However, the effects of light water reactor (LWR) coolant environments are not explicitly addressed by the Code design curves. The existing fatigue strain-vs.-life ({var_epsilon}-N) data illustrate potentially significant effects of LWR coolant environments on the fatigue resistance of pressure vessel and piping steels. Under certain environmental and loading conditions, fatigue lives of austenitic stainless steels (SSs) can be a factor of 20 lower in water than in air. This report presents experimental data on the effect of heat treatment on fatigue crack initiation in austenitic Type 304 SS in LWR coolant environments. A detailed metallographic examination of fatigue test specimens was performed to characterize the crack morphology and fracture morphology. The key material, loading, and environmental parameters and their effect on the fatigue life of these steels are also described. Statistical models are presented for estimating the fatigue {var_epsilon}-N curves for austenitic SSs as a function of material, loading, and environmental parameters. Two methods for incorporating the effects of LWR coolant environments into the ASME Code fatigue evaluations are presented.

  16. Technical report on LWR design decision methodology. Phase I

    SciTech Connect

    1980-03-01

    Energy Incorporated (EI) was selected by Sandia Laboratories to develop and test on LWR design decision methodology. Contract Number 42-4229 provided funding for Phase I of this work. This technical report on LWR design decision methodology documents the activities performed under that contract. Phase I was a short-term effort to thoroughly review the curret LWR design decision process to assure complete understanding of current practices and to establish a well defined interface for development of initial quantitative design guidelines.

  17. Radiation Chemistry in Ammonia-Water Ices

    NASA Technical Reports Server (NTRS)

    Loeffler, M. J.; Raut, U.; Baragiola, R. A.

    2010-01-01

    We studied the effects of 100 keV proton irradiation on films of ammonia-water mixtures between 20 and 120 K. Irradiation destroys ammonia, leading to the formation and trapping of H2, N2 NO, and N2O, the formation of cavities containing radiolytic gases, and ejection of molecules by sputtering. Using infrared spectroscopy, we show that at all temperatures the destruction of ammonia is substantial, but at higher temperatures (120 K), it is nearly complete (approximately 97% destroyed) after a fluence of 10(exp 16) ions per square centimeter. Using mass spectroscopy and microbalance gravimetry, we measure the sputtering yield of our sample and the main components of the sputtered flux. We find that the sputtering yield depends on fluence. At low temperatures, the yield is very low initially and increases quadratically with fluence, while at 120 K the yield is constant and higher initially. The increase in the sputtering yield with fluence is explained by the formation and trapping of the ammonia decay products, N2 and H2 which are seen to be ejected from the ice at all temperatures.

  18. Radiation Chemistry in Ammonia-Water Ices

    NASA Technical Reports Server (NTRS)

    Loeffler, M. J.; Raut, U.; Baragiola, R. A.

    2010-01-01

    We studied the effects of 100 keV proton irradiation on films of ammonia-water mixtures between 20 and 120 K. Irradiation destroys ammonia, leading to the formation and trapping of H2, N2 NO, and N2O, the formation of cavities containing radiolytic gases, and ejection of molecules by sputtering. Using infrared spectroscopy, we show that at all temperatures the destruction of ammonia is substantial, but at higher temperatures (120 K), it is nearly complete (approximately 97% destroyed) after a fluence of 10(exp 16) ions per square centimeter. Using mass spectroscopy and microbalance gravimetry, we measure the sputtering yield of our sample and the main components of the sputtered flux. We find that the sputtering yield depends on fluence. At low temperatures, the yield is very low initially and increases quadratically with fluence, while at 120 K the yield is constant and higher initially. The increase in the sputtering yield with fluence is explained by the formation and trapping of the ammonia decay products, N2 and H2 which are seen to be ejected from the ice at all temperatures.

  19. OT1_swampfle_1: WATCH - WATer Chemistry with Herschel

    NASA Astrophysics Data System (ADS)

    Wampfler, S.

    2010-07-01

    Water is one of the most abundant species in star-forming regions and plays important roles in both the energy balance, acting as a coolant, and the chemistry of star formation. Many of the species involved in the water chemistry emit in the far-infrared and are thus not observable from ground based facilities because of atmospheric absorption. Therefore, the Herschel Space Observatory provides a unique opportunity to study the chemical reactions involved in the formation and destruction of water and to probe the energetic processes in star-forming regions. Previous results from Herschel have shown that two species, OH+ and H2O+, that were thought to be important in the water chemistry of young stellar objects, are now mainly attributed to foreground clouds. These results raised the question on which chemical paths the formation and destruction of water takes place in the interior of protostellar envelopes. In this proposal, we plan to observe the different formation and destruction routes of water in a sample of eight nearby young stellar objects, which were chosen to cover a broad range of masses, luminosities and evolutionary stages. We propose to observe H3O+ and HCO+, two species that are closely linked to the formation and destruction of H2O and require high temperatures for excitation, in serveral high-J lines. This effort is complementary to the observations of H2O and OH done in the 'Water in star-forming regions with Herschel (WISH)' key project. The combination of the information from the H2O, OH, H3O+ and HCO+ emission will tell us on which routes the formation and destruction of H2O in protostellar envelopes proceeds.

  20. HIGH TEMPERATURE THERMAL AND STRUCTURAL MATERIAL PROPERTIES FOR METALS USED IN LWR VESSELS

    SciTech Connect

    J.L. Rempe; D.L. Knudson; J. E. Daw; J. C. Crepeau

    2008-06-01

    Because of the impact that melt relocation and vessel failure may have on subsequent progression and associated consequences of a Light Water Reactor (LWR) accident, it is important to accurately predict heating and relocation of materials within the reactor vessel, heat transfer to and from the reactor vessel, and the potential for failure of the vessel and structures within it. Accurate predictions of such phenomena require high temperature thermal and structural properties. However, a review of vessel and structural steel material properties used in severe accident analysis codes reveals that the required high temperature material properties are extrapolated with little, if any, data above 1000 K. To reduce uncertainties in predictions relying upon extrapolated high temperature data, Idaho National Laboratory (INL) obtained high data for two metals used in LWR vessels: SA 533 Grade B, Class 1 (SA533B1) low alloy steel, which is used to fabricate most US LWR reactor vessels; and Type 304 Stainless Steel SS304, which is used in LWR vessel piping, penetration tubes, and internal structures. This paper summarizes the new data, and compares it to existing data.

  1. Main contributions of the KfK nuclear safety project in the LWR safety area

    SciTech Connect

    Kuczera, B.

    1986-01-01

    The Nuclear Safety Project (PNS) was established at the Kernforschungszentrum Karlsruhe (KfK) in 1972. At that time, nuclear energy in the Federal Republic of Germany was in a transition phase proceeding from light water reactor (LWR) demonstration plants (300 MW(e)) to commercial size plants of 1200 to 1300 MW(e) which are standard units today. Simultaneously, general questions about LWR safety and reliability as well as questions on risk-oriented features became more pronounced in the public discussion. As a consequence, various already existing LWR safety activities were brought together and combined in the organizational framework of the PNS. The overriding objectives of PNS research and development (R and D) effort were at the quantification of safety margins of reactor systems and components, and the improvement of existing safety systems to avoid accident occurrence and to minimize accident consequences. In close cooperation with governmental authorities, manufacturers, and utilities, an R and D program was developed, comprised of four main areas: 1) dynamic behavior of reactor components; 2) fuel element behavior under accident conditions; 3) core meltdown accident analyses; and 4) retention of radioactive fission products and limitation of severe accident consequences. An overview on the KfK contribution to LWR safety research is given. It deals in a comprehensive matter with results obtained in the areas listed above.

  2. Guidelines and techniques for obtaining water samples that accurately represent the water chemistry of an aquifer

    USGS Publications Warehouse

    Claassen, Hans C.

    1982-01-01

    Obtaining ground-water samples that accurately represent the water chemistry of an aquifer is a complex task. Before a ground-water sampling program can be started, an understanding of the kind of chemical data needed and the potential changes in water chemistry resulting from various drilling, well-completion, and sampling techniques is needed. This report provides a basis for such an evaluation and permits a choice of techniques that will result in obtaining the best possible data for the time and money allocated.

  3. LWR spent fuel reduction by the removal of U and the compact storage of Pu with FP for long-term nuclear sustainability

    SciTech Connect

    Fukasawa, T.; Hoshino, K.; Takano, M.; Sato, S.; Shimazu, Y.

    2013-07-01

    Fast breeder reactors (FBR) nuclear fuel cycle is needed for long-term nuclear sustainability while preventing global warming and maximum utilizing the limited uranium (U) resources. The 'Framework for Nuclear Energy Policy' by the Japanese government on October 2005 stated that commercial FBR deployment will start around 2050 under its suitable conditions by the successive replacement of light water reactors (LWR) to FBR. Even after Fukushima Daiichi Nuclear Power Plant accident which made Japanese tendency slow down the nuclear power generation activities, Japan should have various options for energy resources including nuclear, and also consider the delay of FBR deployment and increase of LWR spent fuel (LWR-SF) storage amounts. As plutonium (Pu) for FBR deployment will be supplied from LWR-SF reprocessing and Japan will not possess surplus Pu, the authors have developed the flexible fuel cycle initiative (FFCI) for the transition from LWR to FBR. The FFCI system is based on the possibility to stored recycled materials (U, Pu)temporarily for a suitable period according to the FBR deployment rate to control the Pu demand/supply balance. This FFCI system is also effective after the Fukushima accident for the reduction of LWR-SF and future LWR-to-FBR transition. (authors)

  4. Chemistry of Stream Sediments and Surface Waters in New England

    USGS Publications Warehouse

    Robinson,, Gilpin R.; Kapo, Katherine E.; Grossman, Jeffrey N.

    2004-01-01

    Summary -- This online publication portrays regional data for pH, alkalinity, and specific conductance for stream waters and a multi-element geochemical dataset for stream sediments collected in the New England states of Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont. A series of interpolation grid maps portray the chemistry of the stream waters and sediments in relation to bedrock geology, lithology, drainage basins, and urban areas. A series of box plots portray the statistical variation of the chemical data grouped by lithology and other features.

  5. Effects of LWR coolant environments on fatigue lives of austenitic stainless steels

    SciTech Connect

    Chopra, O.K.; Gavenda, D.J.

    1997-07-01

    The ASME Boiler and Pressure Vessel Code fatigue design curves for structural materials do not explicitly address the effects of reactor coolant environments on fatigue life. Recent test data indicate a significant decrease in fatigue life of pressure vessel and piping materials in light water reactor (LWR) environments. Fatigue tests have been conducted on Types 304 and 316NG stainless steel in air and LWR environments to evaluate the effects of various material and loading variables, e.g., steel type, strain rate, dissolved oxygen (DO) in water, and strain range, on fatigue lives of these steels. The results confirm the significant decrease in fatigue life in water. The environmentally assisted decrease in fatigue life depends both on strain rate and DO content in water. A decrease in strain rate from 0.4 to 0.004%/s decreases fatigue life by a factor of {approx} 8. However, unlike carbon and low-alloy steels, environmental effects are more pronounced in low-DO than in high-DO water. At {approx} 0.004%/s strain rate, reduction in fatigue life in water containing <10 ppb D is greater by a factor of {approx} 2 than in water containing {ge} 200 ppb DO. Experimental results have been compared with estimates of fatigue life based on the statistical model. The formation and growth of fatigue cracks in austenitic stainless steels in air and LWR environments are discussed.

  6. The Role of Water Chemistry in Marine Aquarium Design: A Model System for a General Chemistry Class

    ERIC Educational Resources Information Center

    Keaffaber, Jeffrey J.; Palma, Ramiro; Williams, Kathryn R.

    2008-01-01

    Water chemistry is central to aquarium design, and it provides many potential applications for discussion in undergraduate chemistry and engineering courses. Marine aquaria and their life support systems feature many chemical processes. A life support system consists of the entire recirculation system, as well as the habitat tank and all ancillary…

  7. The Role of Water Chemistry in Marine Aquarium Design: A Model System for a General Chemistry Class

    ERIC Educational Resources Information Center

    Keaffaber, Jeffrey J.; Palma, Ramiro; Williams, Kathryn R.

    2008-01-01

    Water chemistry is central to aquarium design, and it provides many potential applications for discussion in undergraduate chemistry and engineering courses. Marine aquaria and their life support systems feature many chemical processes. A life support system consists of the entire recirculation system, as well as the habitat tank and all ancillary…

  8. Evaluation of formation water chemistry and scale prediction: Bakken Shale

    SciTech Connect

    Thyne, Geoffrey; Brady, Patrick

    2016-10-24

    Determination of in situ formation water chemistry is an essential component of reservoir management. This study details the use of thermodynamic computer models to calculate reservoir pH and restore produced water analyses for prediction of scale formation. Bakken produced water samples were restored to formation conditions and calculations of scale formation performed. In situ pH is controlled by feldspar-clay equilibria. Calcite scale is readily formed due to changes in pH during pressure drop from in situ to surface conditions. The formation of anhydrite and halite scale, which has been observed, was predicted only for the most saline samples. Finally, in addition, the formation of anhydrite and/or halite may be related to the localized conditions of increased salinity as water is partitioned into the gas phase during production.

  9. Evaluation of formation water chemistry and scale prediction: Bakken Shale

    DOE PAGES

    Thyne, Geoffrey; Brady, Patrick

    2016-10-24

    Determination of in situ formation water chemistry is an essential component of reservoir management. This study details the use of thermodynamic computer models to calculate reservoir pH and restore produced water analyses for prediction of scale formation. Bakken produced water samples were restored to formation conditions and calculations of scale formation performed. In situ pH is controlled by feldspar-clay equilibria. Calcite scale is readily formed due to changes in pH during pressure drop from in situ to surface conditions. The formation of anhydrite and halite scale, which has been observed, was predicted only for the most saline samples. Finally, inmore » addition, the formation of anhydrite and/or halite may be related to the localized conditions of increased salinity as water is partitioned into the gas phase during production.« less

  10. Thermal Properties of Structural Materials Used in LWR Vessels

    SciTech Connect

    J. E. Daw; J. L. Rempe; D. L. Knudson

    2011-01-01

    High temperature material property data for structural materials used in existing Light Water Reactors (LWRs) are limited. Often, extrapolated values recommended in the literature differ significantly. To reduce uncertainties in predictions relying upon extrapolated data for LWR vessel and penetration materials, high temperature tests were completed on SA533 Grade B, Class 1 (SA533B1) low alloy steel, Stainless Steel 304 (SS304), and Inconel 600 using material property measurement systems available in the High Temperature Test Laboratory (HTTL) at the Idaho National Laboratory (INL). Properties measured include thermal expansion, specific heat capacity, and thermal diffusivity for temperatures up to 1200 °C. From these results, thermal conductivity and density were calculated. Results show that, in some cases, previously recommended values for these materials differ significantly from measured values at high temperatures.

  11. Release of fission gas during transient heating of LWR fuel

    SciTech Connect

    Gehl, S.M.

    1982-05-01

    The direct electrical heating technique was used to study fission-gas release and mechanical behavior of irradiated light-water reactor (LWR) fuels during thermal transients. An empirical correlation between fission-gas release and transient temperature history was developed for power-cooling mismatch (PCM) and anticipated transients. Gas release during the refill portion of a design-basis loss of cooling accident was estimated to be less than 1%. Fission-gas release during PCM accidents was found to be controlled by intergranular microcracking and the interlinkage of tunnels on grain edges. For high-gas-release transients, the fractional gas release was shown to be equal to the fractional coverage of grain boundaries by microcracks. Temperature calculations indicated that microcracking causes a significant decrease in the fuel thermal conductivity.

  12. The Chemistry and Excitation of Water in Molecular Clouds

    NASA Technical Reports Server (NTRS)

    Hollenbach, David

    2003-01-01

    We model the chemistry and thermal balance of opaque molecular clouds exposed to an external flux of ultraviolet photons. We include the processes of gas phase and grain surface chemical reactions; in particular we examine closely the freezing of atoms and molecules onto grain surfaces and the desorption of molecules from grain surfaces as a function of depth into a molecular cloud. We find that on the surface of a molecular cloud the gas phase water abundances are low because of photodissociation, and the grain phase water (ice) abundance is low because of photodesorption of water from the grain surfaces. Deeper into the cloud, at A(sub v) less than or approximately 2-8 depending on the strength of the external ultraviolet flux, the gas phase water abundance increases with depth as the photodissociation rates decline due to dust attenuation of the ultraviolet field. However, beyond A(sub v) less than or approximately 2-8 the gas phase water abundance declines because the water freezes as water ice on the grains, and photodesorption is no longer effective in clearing the ice. A peak water abundance of about 10(exp -6) to 10(exp -7) occurs at about A(sub v) approximately 2-8, relatively independent of the gas density and the ultraviolet field. We show that such a model matches very closely the observations of the Submillimeter Wave Astronomical Satellite (SWAS), a NASA Small Explorer Mission. The model elucidates several mechanisms that have been recently invoked to understand gas phase chemistry in clouds, including-the freeze-out of molecules onto grain surface, the desorption of these molecules from the surfaces, and the abundance gradients of molecules as functions of depth into molecular clouds.

  13. The Chemistry and Excitation of Water in Molecular Clouds

    NASA Technical Reports Server (NTRS)

    Hollenbach, David

    2003-01-01

    We model the chemistry and thermal balance of opaque molecular clouds exposed to an external flux of ultraviolet photons. We include the processes of gas phase and grain surface chemical reactions; in particular we examine closely the freezing of atoms and molecules onto grain surfaces and the desorption of molecules from grain surfaces as a function of depth into a molecular cloud. We find that on the surface of a molecular cloud the gas phase water abundances are low because of photodissociation, and the grain phase water (ice) abundance is low because of photodesorption of water from the grain surfaces. Deeper into the cloud, at A(sub v) less than or approximately 2-8 depending on the strength of the external ultraviolet flux, the gas phase water abundance increases with depth as the photodissociation rates decline due to dust attenuation of the ultraviolet field. However, beyond A(sub v) less than or approximately 2-8 the gas phase water abundance declines because the water freezes as water ice on the grains, and photodesorption is no longer effective in clearing the ice. A peak water abundance of about 10(exp -6) to 10(exp -7) occurs at about A(sub v) approximately 2-8, relatively independent of the gas density and the ultraviolet field. We show that such a model matches very closely the observations of the Submillimeter Wave Astronomical Satellite (SWAS), a NASA Small Explorer Mission. The model elucidates several mechanisms that have been recently invoked to understand gas phase chemistry in clouds, including-the freeze-out of molecules onto grain surface, the desorption of these molecules from the surfaces, and the abundance gradients of molecules as functions of depth into molecular clouds.

  14. Evaluation of FSV-1 cask for the transport of LWR irradiated fuel assemblies

    SciTech Connect

    Not Available

    1980-05-01

    The Model FSV-1 spent fuel shipping cask was designed by General Atomic Company (GA) to service the Fort St. Vrain (FSV) nuclear generating station, a High Temperature Gas Reactor (HTGR) owned and operated by Public Service Company of Colorado (PSC). This report presents an evaluation of the suitability of the FSV-1 cask for the transport of irradiated Light Water Reactor (LWR) fuel assemblies from both Pressurized Water Reactors (PWR) and Boiling Water Reactors (BWR). The FSV-1 cask evaluation parameters covered a wide spectrum of LWR fuel assemblies, based on burnup in Megawatt Days/Metric Ton of Heavy Metal (MWD/MTHM) and years of decay since irradiation. The criteria for suitability included allowable radiation dose rates, cask surface and interior temperatures and the Gross Vehicle Weight (GVW) of the complete shipping system.

  15. Reacting chemistry at the air-water interface

    NASA Astrophysics Data System (ADS)

    Murakami, Tomoyuki; Morgan, Thomas; Huwel, Lutz; Graham, William

    2016-09-01

    Plasma interaction with gas-liquid interfaces is becoming increasingly important in biological applications, chemical analysis and medicine. It introduces electrons, new ionic species and reactive species and contributes to chemical and electrical self-organization at the interface. To provide insight into the associated physics and chemistry at work in the evolution of the plasma in the air-water interface (AWI), a time-dependent one-dimensional modelling has been developed. The numerical simulation is used to solve the kinetic equations and help identify the important reaction mechanisms and describe the phenomena associated with hundreds of reacting pathways in gas-phase and liquid-phase AWI chemistry. This work was partly supported by JSPS KAKENHI Grant Number 16K04998.

  16. Comparative analysis of LWR and FBR spent fuels for nuclear forensics evaluation

    SciTech Connect

    Permana, Sidik; Suzuki, Mitsutoshi; Su'ud, Zaki

    2012-06-06

    Some interesting issues are attributed to nuclide compositions of spent fuels from thermal reactors as well as fast reactors such as a potential to reuse as recycled fuel, and a possible capability to be manage as a fuel for destructive devices. In addition, analysis on nuclear forensics which is related to spent fuel compositions becomes one of the interesting topics to evaluate the origin and the composition of spent fuels from the spent fuel foot-prints. Spent fuel compositions of different fuel types give some typical spent fuel foot prints and can be estimated the origin of source of those spent fuel compositions. Some technics or methods have been developing based on some science and technological capability including experimental and modeling or theoretical aspects of analyses. Some foot-print of nuclear forensics will identify the typical information of spent fuel compositions such as enrichment information, burnup or irradiation time, reactor types as well as the cooling time which is related to the age of spent fuels. This paper intends to evaluate the typical spent fuel compositions of light water (LWR) and fast breeder reactors (FBR) from the view point of some foot prints of nuclear forensics. An established depletion code of ORIGEN is adopted to analyze LWR spent fuel (SF) for several burnup constants and decay times. For analyzing some spent fuel compositions of FBR, some coupling codes such as SLAROM code, JOINT and CITATION codes including JFS-3-J-3.2R as nuclear data library have been adopted. Enriched U-235 fuel composition of oxide type is used for fresh fuel of LWR and a mixed oxide fuel (MOX) for FBR fresh fuel. Those MOX fuels of FBR come from the spent fuels of LWR. Some typical spent fuels from both LWR and FBR will be compared to distinguish some typical foot-prints of SF based on nuclear forensic analysis.

  17. Comparative analysis of LWR and FBR spent fuels for nuclear forensics evaluation

    NASA Astrophysics Data System (ADS)

    Permana, Sidik; Suzuki, Mitsutoshi; Su'ud, Zaki

    2012-06-01

    Some interesting issues are attributed to nuclide compositions of spent fuels from thermal reactors as well as fast reactors such as a potential to reuse as recycled fuel, and a possible capability to be manage as a fuel for destructive devices. In addition, analysis on nuclear forensics which is related to spent fuel compositions becomes one of the interesting topics to evaluate the origin and the composition of spent fuels from the spent fuel foot-prints. Spent fuel compositions of different fuel types give some typical spent fuel foot prints and can be estimated the origin of source of those spent fuel compositions. Some technics or methods have been developing based on some science and technological capability including experimental and modeling or theoretical aspects of analyses. Some foot-print of nuclear forensics will identify the typical information of spent fuel compositions such as enrichment information, burnup or irradiation time, reactor types as well as the cooling time which is related to the age of spent fuels. This paper intends to evaluate the typical spent fuel compositions of light water (LWR) and fast breeder reactors (FBR) from the view point of some foot prints of nuclear forensics. An established depletion code of ORIGEN is adopted to analyze LWR spent fuel (SF) for several burnup constants and decay times. For analyzing some spent fuel compositions of FBR, some coupling codes such as SLAROM code, JOINT and CITATION codes including JFS-3-J-3.2R as nuclear data library have been adopted. Enriched U-235 fuel composition of oxide type is used for fresh fuel of LWR and a mixed oxide fuel (MOX) for FBR fresh fuel. Those MOX fuels of FBR come from the spent fuels of LWR. Some typical spent fuels from both LWR and FBR will be compared to distinguish some typical foot-prints of SF based on nuclear forensic analysis.

  18. Size resolved fog water chemistry and its atmospheric implications

    NASA Astrophysics Data System (ADS)

    Chakraborty, Abhishek; Gupta, Tarun; Tripathi, Sachchida; Ervens, Barbara; Bhattu, Deepika

    2015-04-01

    Fog is a natural meteorological phenomenon that occurs throughout the world. It usually contains substantial quantity of liquid water and results in severe visibility reduction leading to disruption of normal life. Fog is generally seen as a natural cleansing agent but it also has the potential to form Secondary Organic Aerosol (SOA) via aqueous processing of ambient aerosols. Size- resolved fog water chemistry for inorganics were reported in previous studies but processing of organics inside the fog water and quantification of aqSOA remained a challenge. To assess the organics processing via fog aqueous processing, size resolved fog water samples were collected in two consecutive winter seasons (2012-13, 2013-14) at Kanpur, a heavily polluted urban area of India. Caltech 3 stage fog collector was used to collect the fog droplets in 3 size fraction; coarse (droplet diameter > 22 µm), medium (22> droplet diameter >16 µm) and fine (16> droplet diameter >4 µm). Collected samples were atomized into various instruments such as Aerosol Mass Spectrometer (AMS), Cloud Condensation Nucleus Counter (CCNc), Total Organic Carbon (TOC) and a thermo denuder (TD) for the physico-chemical characterization of soluble constituents. Fine droplets are found to be more enriched with different aerosol species and interestingly contain more aged and less volatile organics compared to other coarser sizes. Organics inside fine droplets have an average O/C = 0.87 compared to O/C of 0.67 and 0.74 of coarse and medium droplets. Metal chemistry and higher residence time of fine droplets are seemed to be the two most likely reasons for this outcome from as the results of a comprehensive modeling carried out on the observed data indicate. CCN activities of the aerosols from fine droplets are also much higher than that of coarse or medium droplets. Fine droplets also contain light absorbing material as was obvious from their 'yellowish' solution. Source apportionment of fog water organics via

  19. Multilevel transport solution of LWR reactor cores

    SciTech Connect

    Jose Ignacio Marquez Damian; Cassiano R.E. de Oliveira; HyeonKae Park

    2008-09-01

    This work presents a multilevel approach for the solution of the transport equation in typical LWR assemblies and core configurations. It is based on the second-order, even-parity formulation of the transport equation, which is solved within the framework provided by the finite element-spherical harmonics code EVENT. The performance of the new solver has been compared with that of the standard conjugate gradient solver for diffusion and transport problems on structured and unstruc-tured grids. Numerical results demonstrate the potential of the multilevel scheme for realistic reactor calculations.

  20. Multiscale Drivers of Water Chemistry of Boreal Lakes and Streams

    PubMed Central

    Johnson, Richard K.

    2006-01-01

    The variability in surface water chemistry within and between aquatic ecosystems is regulated by many factors operating at several spatial and temporal scales. The importance of geographic, regional-, and local-scale factors as drivers of the natural variability of three water chemistry variables representing buffering capacity and the importance of weathering (acid neutralizing capacity, ANC), nutrient concentration (total phosphorus, TP), and importance of allochthonous inputs (total organic carbon, TOC) were studied in boreal streams and lakes using a method of variance decomposition. Partial redundancy analysis (pRDA) of ANC, TP, and TOC and 38 environmental variables in 361 lakes and 390 streams showed the importance of the interaction between geographic position and regional-scale variables. Geographic position and regional-scale factors combined explained 15.3% (streams) and 10.6% (lakes) of the variation in ANC, TP, and TOC. The unique variance explained by geographic, regional, and local-scale variables alone was <10%. The largest amount of variance was explained by the pure effect of regional-scale variables (9.9% for streams and 7.8% for lakes), followed by local-scale variables (2.9% and 5.8%) and geographic position (1.8% and 3.7%). The combined effect of geographic position, regional-, and local-scale variables accounted for between 30.3% (lakes) and 39.9% (streams) of the variance in surface water chemistry. These findings lend support to the conjecture that lakes and streams are intimately linked to their catchments and have important implications regarding conservation and restoration (management) endeavors. PMID:16955233

  1. Optimum Water Chemistry in radiation field buildup control

    SciTech Connect

    Lin, Chien, C.

    1995-03-01

    Nuclear utilities continue to face the challenGE of reducing exposure of plant maintenance personnel. GE Nuclear Energy has developed the concept of Optimum Water Chemistry (OWC) to reduce the radiation field buildup and minimize the radioactive waste production. It is believed that reduction of radioactive sources and improvement of the water chemistry quality should significantly reduce both the radiation exposure and radwaste production. The most important source of radioactivity is cobalt and replacement of cobalt containing alloy in the core region as well as in the entire primary system is considered the first priority to achieve the goal of low exposure and minimized waste production. A plant specific computerized cobalt transport model has been developed to evaluate various options in a BWR system under specific conditions. Reduction of iron input and maintaining low ionic impurities in the coolant have been identified as two major tasks for operators. Addition of depleted zinc is a proven technique to reduce Co-60 in reactor water and on out-of-core piping surfaces. The effect of HWC on Co-60 transport in the primary system will also be discussed.

  2. Influence of surface structure and chemistry on water droplet splashing.

    PubMed

    Koch, Kerstin; Grichnik, Roland

    2016-08-06

    Water droplet splashing and aerosolization play a role in human hygiene and health systems as well as in crop culturing. Prevention or reduction of splashing can prevent transmission of diseases between animals and plants and keep technical systems such as pipe or bottling systems free of contamination. This study demonstrates to what extent the surface chemistry and structures influence the water droplet splashing behaviour. Smooth surfaces and structured replicas of Calathea zebrina (Sims) Lindl. leaves were produced. Modification of their wettability was done by coating with hydrophobizing and hydrophilizing agents. Their wetting was characterized by contact angle measurement and splashing behaviour was observed with a high-speed video camera. Hydrophobic and superhydrophilic surfaces generally showed fewer tendencies to splash than hydrophobic ones. Structuring amplified the underlying behaviour of the surface chemistries, increasing hydrophobic surfaces' tendency to splash and decreasing splash on hydrophilic surfaces by quickly transporting water off the impact point by capillary forces. The non-porous surface structures found in C. zebrina could easily be applied to technical products such as plastic foils or mats and coated with hydrophilizing agents to suppress splash in areas of increased hygiene requirements or wherever pooling of liquids is not desirable.This article is part of the themed issue 'Bioinspired hierarchically structured surfaces for green science'.

  3. Acid-base chemistry of frustrated water at protein interfaces.

    PubMed

    Fernández, Ariel

    2016-01-01

    Water molecules at a protein interface are often frustrated in hydrogen-bonding opportunities due to subnanoscale confinement. As shown, this condition makes them behave as a general base that may titrate side-chain ammonium and guanidinium cations. Frustration-based chemistry is captured by a quantum mechanical treatment of proton transference and shown to remove same-charge uncompensated anticontacts at the interface found in the crystallographic record and in other spectroscopic information on the aqueous interface. Such observations are untenable within classical arguments, as hydronium is a stronger acid than ammonium or guanidinium. Frustration enables a directed Grotthuss mechanism for proton transference stabilizing same-charge anticontacts.

  4. Validating the BISON fuel performance code to integral LWR experiments

    DOE PAGES

    Williamson, R. L.; Gamble, K. A.; Perez, D. M.; ...

    2016-03-24

    BISON is a modern finite element-based nuclear fuel performance code that has been under development at the Idaho National Laboratory (INL) since 2009. The code is applicable to both steady and transient fuel behavior and has been used to analyze a variety of fuel forms in 1D spherical, 2D axisymmetric, or 3D geometries. Code validation is underway and is the subject of this study. A brief overview of BISON’s computational framework, governing equations, and general material and behavioral models is provided. BISON code and solution verification procedures are described, followed by a summary of the experimental data used to datemore » for validation of Light Water Reactor (LWR) fuel. Validation comparisons focus on fuel centerline temperature, fission gas release, and rod diameter both before and following fuel-clad mechanical contact. Comparisons for 35 LWR rods are consolidated to provide an overall view of how the code is predicting physical behavior, with a few select validation cases discussed in greater detail. Our results demonstrate that 1) fuel centerline temperature comparisons through all phases of fuel life are very reasonable with deviations between predictions and experimental data within ±10% for early life through high burnup fuel and only slightly out of these bounds for power ramp experiments, 2) accuracy in predicting fission gas release appears to be consistent with state-of-the-art modeling and with the involved uncertainties and 3) comparison of rod diameter results indicates a tendency to overpredict clad diameter reduction early in life, when clad creepdown dominates, and more significantly overpredict the diameter increase late in life, when fuel expansion controls the mechanical response. In the initial rod diameter comparisons they were unsatisfactory and have lead to consideration of additional separate effects experiments to better understand and predict clad and fuel mechanical behavior. Results from this study are being used to

  5. Validating the BISON fuel performance code to integral LWR experiments

    SciTech Connect

    Williamson, R. L.; Gamble, K. A.; Perez, D. M.; Novascone, S. R.; Pastore, G.; Gardner, R. J.; Hales, J. D.; Liu, W.; Mai, A.

    2016-03-24

    BISON is a modern finite element-based nuclear fuel performance code that has been under development at the Idaho National Laboratory (INL) since 2009. The code is applicable to both steady and transient fuel behavior and has been used to analyze a variety of fuel forms in 1D spherical, 2D axisymmetric, or 3D geometries. Code validation is underway and is the subject of this study. A brief overview of BISON’s computational framework, governing equations, and general material and behavioral models is provided. BISON code and solution verification procedures are described, followed by a summary of the experimental data used to date for validation of Light Water Reactor (LWR) fuel. Validation comparisons focus on fuel centerline temperature, fission gas release, and rod diameter both before and following fuel-clad mechanical contact. Comparisons for 35 LWR rods are consolidated to provide an overall view of how the code is predicting physical behavior, with a few select validation cases discussed in greater detail. Our results demonstrate that 1) fuel centerline temperature comparisons through all phases of fuel life are very reasonable with deviations between predictions and experimental data within ±10% for early life through high burnup fuel and only slightly out of these bounds for power ramp experiments, 2) accuracy in predicting fission gas release appears to be consistent with state-of-the-art modeling and with the involved uncertainties and 3) comparison of rod diameter results indicates a tendency to overpredict clad diameter reduction early in life, when clad creepdown dominates, and more significantly overpredict the diameter increase late in life, when fuel expansion controls the mechanical response. In the initial rod diameter comparisons they were unsatisfactory and have lead to consideration of additional separate effects experiments to better understand and predict clad and fuel mechanical behavior. Results from this study are being used to define

  6. Short communication on "In-situ TEM ion irradiation investigations on U3Si2 at LWR temperatures"

    DOE PAGES

    Miao, Yinbin; Harp, Jason; Mo, Kun; ...

    2016-11-21

    Here, the radiation-induced amorphization of U3Si2 was investigated by in-situ transmission electron microscopy using 1 MeV Kr ion irradiation. Both arc-melted and sintered U3Si2 specimens were irradiated at room temperature to confirm the similarity in their responses to radiation. The sintered specimens were then irradiated at 350 °C and 550 °C up to 7.2 × 1015 ions/cm2 to examine their amorphization behavior under light water reactor (LWR) conditions. U3Si2 remains crystalline under irradiation at LWR temperatures. Oxidation of the material was observed at high irradiation doses.

  7. Short Communication on "In-situ TEM ion irradiation investigations on U3Si2 at LWR temperatures"

    NASA Astrophysics Data System (ADS)

    Miao, Yinbin; Harp, Jason; Mo, Kun; Bhattacharya, Sumit; Baldo, Peter; Yacout, Abdellatif M.

    2017-02-01

    The radiation-induced amorphization of U3Si2 was investigated by in-situ transmission electron microscopy using 1 MeV Kr ion irradiation. Both arc-melted and sintered U3Si2 specimens were irradiated at room temperature to confirm the similarity in their responses to radiation. The sintered specimens were then irradiated at 350 °C and 550 °C up to 7.2 × 1015 ions/cm2 to examine their amorphization behavior under light water reactor (LWR) conditions. U3Si2 remains crystalline under irradiation at LWR temperatures. Oxidation of the material was observed at high irradiation doses.

  8. Technical program to study the benefits of nonlinear analysis methods in LWR component designs. Technical report TR-3723-1

    SciTech Connect

    Raju, P. P.

    1980-05-01

    This report summarizes the results of the study program to assess the benefits of nonlinear analysis methods in Light Water Reactor (LWR) component designs. The current study reveals that despite its increased cost and other complexities, nonlinear analysis is a practical and valuable tool for the design of LWR components, especially under ASME Level D service conditions (faulted conditions) and it will greatly assist in the evaluation of ductile fracture potential of pressure boundary components. Since the nonlinear behavior is generally a local phenomenon, the design of complex components can be accomplished through substructuring isolated localized regions and evaluating them in detail using nonlinear analysis methods.

  9. Assessing background ground water chemistry beneath a new unsewered subdivision

    USGS Publications Warehouse

    Wilcox, J.D.; Bradbury, K.R.; Thomas, C.L.; Bahr, J.M.

    2005-01-01

    Previous site-specific studies designed to assess the impacts of unsewered subdivisions on ground water quality have relied on upgradient monitoring wells or very limited background data to characterize conditions prior to development. In this study, an extensive monitoring program was designed to document ground water conditions prior to construction of a rural subdivision in south-central Wisconsin. Previous agricultural land use has impacted ground water quality; concentrations of chloride, nitrate-nitrogen, and atrazine ranged from below the level of detection to 296 mg/L, 36 mg/L, and 0.8 ??g/L, respectively, and were highly variable from well to well and through time. Seasonal variations in recharge, surface topography, aquifer heterogeneities, surficial loading patterns, and well casing depth explain observed variations in ground water chemistry. This variability would not have been detected if background conditions were determined from only a few monitoring wells or inferred from wells located upgradient of the subdivision site. This project demonstrates the importance of characterizing both ground water quality and chemical variability prior to land-use change to detect any changes once homes are constructed. Copyright ?? 2005 National Ground Water Association.

  10. LIFE vs. LWR: End of the Fuel Cycle

    SciTech Connect

    Farmer, J C; Blink, J A; Shaw, H F

    2008-10-02

    The worldwide energy consumption in 2003 was 421 quadrillion Btu (Quads), and included 162 quads for oil, 99 quads for natural gas, 100 quads for coal, 27 quads for nuclear energy, and 33 quads for renewable sources. The projected worldwide energy consumption for 2030 is 722 quads, corresponding to an increase of 71% over the consumption in 2003. The projected consumption for 2030 includes 239 quads for oil, 190 quads for natural gas, 196 quads for coal, 35 quads for nuclear energy, and 62 quads for renewable sources [International Energy Outlook, DOE/EIA-0484, Table D1 (2006) p. 133]. The current fleet of light water reactors (LRWs) provides about 20% of current U.S. electricity, and about 16% of current world electricity. The demand for electricity is expected to grow steeply in this century, as the developing world increases its standard of living. With the increasing price for oil and gasoline within the United States, as well as fear that our CO2 production may be driving intolerable global warming, there is growing pressure to move away from oil, natural gas, and coal towards nuclear energy. Although there is a clear need for nuclear energy, issues facing waste disposal have not been adequately dealt with, either domestically or internationally. Better technological approaches, with better public acceptance, are needed. Nuclear power has been criticized on both safety and waste disposal bases. The safety issues are based on the potential for plant damage and environmental effects due to either nuclear criticality excursions or loss of cooling. Redundant safety systems are used to reduce the probability and consequences of these risks for LWRs. LIFE engines are inherently subcritical, reducing the need for systems to control the fission reactivity. LIFE engines also have a fuel type that tolerates much higher temperatures than LWR fuel, and has two safety systems to remove decay heat in the event of loss of coolant or loss of coolant flow. These features of

  11. Characteristics of spent fuel, high-level waste, and other radioactive wastes which may require long-term isolation: Appendix 2A, Physical descriptions of LWR (Light-Water Reactor) fuel assemblies

    SciTech Connect

    Not Available

    1987-12-01

    This appendix includes a four-page Physical Description report for each assembly type identified from the current data. Where available, a drawing of an assembly follows the appropriate Physical Description report. If no drawing is available for an assembly, a cross-reference to a similar assembly is provided if possible. For Advanced Nuclear Fuels, Babcock and Wilcox, Combustion Engineering, and Westinghouse assemblies, information was obtained via subcontracts with these fuel vendors. Data for some assembly types are not available. For such assemblies, the information shown in this report was obtained from the open literature and by inference from reload fuels made by other vendors. Efforts to obtain additional information are continuing. Individual Physical Description reports can be generated interactively through the menu-driven LWR Assemblies Data Base system. These reports can be viewed on the screen or directed to a printer. Special reports and compilations of specific data items can be produced on request.

  12. Twenty-fifth water reactor safety information meeting: Proceedings. Volume 1: Plenary sessions; Pressure vessel research; BWR strainer blockage and other generic safety issues; Environmentally assisted degradation of LWR components; Update on severe accident code improvements and applications

    SciTech Connect

    Monteleone, S.

    1998-03-01

    This three-volume report contains papers presented at the conference. The papers are printed in the order of their presentation in each session and describe progress and results of programs in nuclear safety research conducted in this country and abroad. Foreign participation in the meeting included papers presented by researchers from France, Japan, Norway, and Russia. The titles of the papers and the names of the authors have been updated and may differ from those that appeared in the final program of the meeting. This volume contains the following information: (1) plenary sessions; (2) pressure vessel research; (3) BWR strainer blockage and other generic safety issues; (4) environmentally assisted degradation of LWR components; and (5) update on severe accident code improvements and applications. Selected papers have been indexed separately for inclusion in the Energy Science and Technology Database.

  13. Evaluation of inorganic sorbent treatment for LWR coolant process streams

    SciTech Connect

    Roddy, J.W.

    1984-03-01

    This report presents results of a survey of the literature and of experience at selected nuclear installations to provide information on the feasibility of replacing organic ion exchangers with inorganic sorbents at light-water-cooled nuclear power plants. Radioactive contents of the various streams in boiling water reactors and pressurized water reactors were examined. In addition, the methods and performances of current methods used for controlling water quality at these plants were evaluated. The study also includes a brief review of the physical and chemical properties of selected inorganic sorbents. Some attributes of inorganic sorbents would be useful in processing light water reactor (LWR) streams. The inorganic resins are highly resistant to damage from ionizing radiation, and their exchange capacities are generally equivalent to those of organic ion exchangers. However, they are more limited in application, and there are problems with physical integrity, especially in acidic solutions. Research is also needed in the areas of selectivity and anion removal before inorganic sorbents can be considered as replacements for the synthetic organic resins presently used in LWRs. 11 figures, 14 tables.

  14. Lithogenic vs Biogenic Stream Water Chemistry: Following the Solute Flush

    NASA Astrophysics Data System (ADS)

    Bain, D. J.; Anderson, S.; Bullen, T.; Fitzpatrick, J.; Schulz, M.; Vivit, D.; White, A.

    2005-12-01

    Mediterranean hydrologic systems are driven by strong intra-annual variation in precipitation. Summer drought is followed by a pronounced solute flush at the beginning of the wet season. Solutes accumulate near the soil surface during dry periods via evapoconcentration and dry deposition. In a set of nested watersheds draining the Santa Cruz, California marine terraces, a differentiation between shallow soil water with biogenic solutes (enriched via evapotranspiration and biologic nutrient cycling) and deep soil water with lithogenic solutes (imprinted by chemical weathering) allows interpretation of flow pathways to the stream. The shallow soil waters are more concentrated than deep soil waters at the beginning of the wet season. Stream chemistry is a mixture of lithogenic deep soil water and biogenic shallow soil water; we expect the lithogenic component to increase downstream. However, the composition of the water along a downstream transect shows no clear shift to lithogenic compositions downstream, especially in the early wet season. The lithogenic water influence may be minimal as most flow paths are lateral across a thick argillic horizon and rarely encounter lithogenic zones. However, the continued influence of biogenic solutes seems to result from movement of evapoconcentrated water through the flow system. Simultaneous collection of groundwater and soil water along the transect shows the slow movement of flushed solutes through the system. Soil waters generally are most concentrated during the first precipitation events and become increasingly diluted throughout the remainder of the wet season. Immediately following the flushing of shallow soils, a concentration peak is observed in perched groundwater near the drainage divide. A similar peak appears in perched groundwater sequentially downstream, finally appearing in groundwater near the base of the catchment after several months. This pattern of flushed solutes in perched groundwaters may result from the

  15. Seasonal water chemistry variability in the Pangani River basin, Tanzania.

    PubMed

    Selemani, Juma R; Zhang, Jing; Muzuka, Alfred N N; Njau, Karoli N; Zhang, Guosen; Maggid, Arafa; Mzuza, Maureen K; Jin, Jie; Pradhan, Sonali

    2017-09-24

    The stable isotopes of δ(18)O, δ(2)H, and (87)Sr/(86)Sr and dissolved major ions were used to assess spatial and seasonal water chemistry variability, chemical weathering, and hydrological cycle in the Pangani River Basin (PRB), Tanzania. Water in PRB was NaHCO3 type dominated by carbonate weathering with moderate total dissolved solids. Major ions varied greatly, increasing from upstream to downstream. In some stations, content of fluoride and sodium was higher than the recommended drinking water standards. Natural and anthropogenic factors contributed to the lowering rate of chemical weathering; the rate was lower than most of tropical rivers. The rate of weathering was higher in Precambrian than volcanic rocks. (87)Sr/(86)Sr was lower than global average whereas concentration of strontium was higher than global average with mean annual flux of 0.13 × 10(6) mol year(-1). Evaporation and altitude effects have caused enrichment of δ(18)O and δ(2)H in dry season and downstream of the river. Higher d-excess value than global average suggests that most of the stations were supplied by recycled moisture. Rainfall and groundwater were the major sources of surface flowing water in PRB; nevertheless, glacier from Mt. Kilimanjaro has insignificant contribution to the surface water. We recommend measures to be taken to reduce the level of fluoride and sodium before domestic use.

  16. Assessing background ground water chemistry beneath a new unsewered subdivision.

    PubMed

    Wilcox, Jeffrey D; Bradbury, Kenneth R; Thomas, Curtis L; Bahr, Jean M

    2005-01-01

    Previous site-specific studies designed to assess the impacts of unsewered subdivisions on ground water quality have relied on upgradient monitoring wells or very limited background data to characterize conditions prior to development. In this study, an extensive monitoring program was designed to document ground water conditions prior to construction of a rural subdivision in south-central Wisconsin. Previous agricultural land use has impacted ground water quality; concentrations of chloride, nitrate-nitrogen, and atrazine ranged from below the level of detection to 296 mg/L, 36 mg/L, and 0.8 microg/L, respectively, and were highly variable from well to well and through time. Seasonal variations in recharge, surface topography, aquifer heterogeneities, surficial loading patterns, and well casing depth explain observed variations in ground water chemistry. This variability would not have been detected if background conditions were determined from only a few monitoring wells or inferred from wells located upgradient of the subdivision site. This project demonstrates the importance of characterizing both ground water quality and chemical variability prior to land-use change to detect any changes once homes are constructed.

  17. BWR plant-to-fleet water chemistry trends -- Past and present

    SciTech Connect

    Baston, V.F.; Sundberg, L.L.; Huff, J.M.

    1995-12-31

    Good water chemistry control is important for the integrity and satisfactory performance of BWRs. A historical review of selected chemistry performance indicators (e.g., conductivity) illustrates the improved chemistry control today relative to that in the past as well as the ability to evaluate these operational indicators.

  18. Calculation evaluation of multiplying properties of LWR with thorium fuel

    NASA Astrophysics Data System (ADS)

    Shamanin, I. V.; Grachev, V. M.; Knyshev, V. V.; Bedenko, S. V.; Novikova, N. G.

    2017-01-01

    The results of multiplying properties design research of the unit cell and LWR fuel assembly with the high temperature gas-cooled thorium reactor fuel pellet are presented in the work. The calculation evaluation showed the possibility of using thorium in LWR effectively. In this case the amount of fissile isotope is 2.45 times smaller in comparison with the standard loading of LWR. The research and numerical experiments were carried out using the verified accounting code of the program MCU5, modern libraries of evaluated nuclear data and multigroup approximations.

  19. Introduction to Chemistry for Water and Wastewater Treatment Plant Operators. Water and Wastewater Training Program.

    ERIC Educational Resources Information Center

    South Dakota Dept. of Environmental Protection, Pierre.

    Presented are basic concepts of chemistry necessary for operators who manage drinking water treatment plants and wastewater facilities. It includes discussions of chemical terms and concepts, laboratory procedures for basic analyses of interest to operators, and discussions of appropriate chemical calculations. Exercises are included and answer…

  20. Introduction to Chemistry for Water and Wastewater Treatment Plant Operators. Water and Wastewater Training Program.

    ERIC Educational Resources Information Center

    South Dakota Dept. of Environmental Protection, Pierre.

    Presented are basic concepts of chemistry necessary for operators who manage drinking water treatment plants and wastewater facilities. It includes discussions of chemical terms and concepts, laboratory procedures for basic analyses of interest to operators, and discussions of appropriate chemical calculations. Exercises are included and answer…

  1. Proceedings of the 2007 LWR Fuel Performance Meeting / TopFuel 2007 'Zero by 2010'

    SciTech Connect

    2007-07-01

    ANS, ENS, AESJ and KNS are jointly organizing the 2007 International LWR Fuel Performance Meeting following the successful ENS TopFuel meeting held during 22-26 October, 2006 in Salamaca, Spain. Merging three premier nuclear fuel design and performance meetings: the ANS LWR Fuel Performance Meeting, the ENS TopFuel and Asian Water Reactor Fuel Performance Meeting (WRFPM) created this international meeting. The meeting will be held annually on a tri-annual rotational basis in USA, Asia, and Europe. The technical scope of the meeting includes all aspects of nuclear fuel from fuel rod to core design as well as performance experience in commercial and test reactors. The meeting excludes front end and back end fuel issues, however, it covers all front and/or back issues that impact fuel designs and performance.

  2. Challenges in the development of high-fidelity LWR core neutronics tools

    SciTech Connect

    Smith, K.; Forget, B.

    2013-07-01

    Modern computing has made possible the solution of extremely large-scale reactor simulations, and the literature has numerous examples of high-resolution methods (often Monte Carlo) applied to full-core reactor problems. However, there are currently no examples in the literature of application of such 'High-Fidelity' or 'First Principles' methods to operating Light Water Reactor (LWR) analysis. This paper seeks to remind code developers, project managers, and analysts of the many important aspects of LWR simulation that must be incorporated to produce truly high-fidelity analysis tools. The authors offer a monetary prize to the first person (or group) that successfully solves a new two-cycle operational PWR depletion benchmark problem using high-fidelity tools and demonstrates acceptable accuracy by comparison with measured operational plant data (open source) provided to the reactor analysis community. (authors)

  3. Evaluation of methods for decladding LWR fuel for a pyroprocessing-based reprocessing plant

    SciTech Connect

    Bond, W.D.; Mailen, J.C.; Michaels, G.E.

    1992-10-01

    The first step in reprocessing disassembled light-water reactor (LWR) spent fuel is to separate the zirconium-based cladding from the UO{sub 2} fuel. A survey of decladding technologies has been performed to identify candidate decladding processes suitable for LWR fuel and compatible with downstream pyropr for separation of actinides and fission products. Technologies for the primary separation of Zircaloy cladding from oxide fuel and for secondary separations (in most cases, a further decontamination of the cladding) were reviewed. Because cutting of the fuel cladding is a necessary step in all flowsheet options, metal cutting technologies were also briefly evaluated. The assessment of decladding processes resulted in the identification of the three or four potentially attractive options that may warrant additional near-term evaluation. These options are summarized, and major strengths and issues of each option are discussed.

  4. Evaluation of methods for decladding LWR fuel for a pyroprocessing-based reprocessing plant

    SciTech Connect

    Bond, W.D.; Mailen, J.C.; Michaels, G.E.

    1992-10-01

    The first step in reprocessing disassembled light-water reactor (LWR) spent fuel is to separate the zirconium-based cladding from the UO[sub 2] fuel. A survey of decladding technologies has been performed to identify candidate decladding processes suitable for LWR fuel and compatible with downstream pyropr for separation of actinides and fission products. Technologies for the primary separation of Zircaloy cladding from oxide fuel and for secondary separations (in most cases, a further decontamination of the cladding) were reviewed. Because cutting of the fuel cladding is a necessary step in all flowsheet options, metal cutting technologies were also briefly evaluated. The assessment of decladding processes resulted in the identification of the three or four potentially attractive options that may warrant additional near-term evaluation. These options are summarized, and major strengths and issues of each option are discussed.

  5. In-reactor performance of LWR-type tritium targe rods

    SciTech Connect

    Lanning, D.D.; Paxton, M.M.; Crumbaugh, L.

    1992-06-01

    Pacific Northwest Laboratory (PNL) has conducted several one-year irradiation tests of light-water reactor (LWR)-type tritium target rods. This report discusses these tests which have been sponsored by DOE`s Office of New Production Reactors. The first test, designated water capsule-I (WC-1), was conducted in the Advanced Test Reactor (ATR) at DOE`s Idaho National Engineering Laboratory from November 1989 to December 1990. The test vehicle contained a single four-foot target rod within a pressurized water capsule. The capsule maintained the rod at PWR-type water temperature and pressure conditions.

  6. Mechanism and estimation of fatigue crack initiation in austenitic stainless steels in LWR environments.

    SciTech Connect

    Chopra, O. K.; Energy Technology

    2002-08-01

    The ASME Boiler and Pressure Vessel Code provides rules for the construction of nuclear power plant components. Figures I-9.1 through I-9.6 of Appendix I to Section III of the Code specify fatigue design curves for structural materials. However, the effects of light water reactor (LWR) coolant environments are not explicitly addressed by the Code design curves. Existing fatigue strain-vs.-life ({var_epsilon}-N) data illustrate potentially significant effects of LWR coolant environments on the fatigue resistance of pressure vessel and piping steels. This report provides an overview of fatigue crack initiation in austenitic stainless steels in LWR coolant environments. The existing fatigue {var_epsilon}-N data have been evaluated to establish the effects of key material, loading, and environmental parameters (such as steel type, strain range, strain rate, temperature, dissolved-oxygen level in water, and flow rate) on the fatigue lives of these steels. Statistical models are presented for estimating the fatigue {var_epsilon}-N curves for austenitic stainless steels as a function of the material, loading, and environmental parameters. Two methods for incorporating environmental effects into the ASME Code fatigue evaluations are presented. The influence of reactor environments on the mechanism of fatigue crack initiation in these steels is also discussed.

  7. Spent fuel dissolution rates as a function of burnup and water chemistry

    SciTech Connect

    Gray, W.J.

    1998-06-01

    To help provide a source term for performance-assessment calculations, dissolution studies on light-water-reactor (LWR) spent fuel have been conducted over the past few years at Pacific Northwest National Laboratory in support of the Yucca Mountain Site Characterization Project. This report describes that work for fiscal years 1996 through mid-1998 and includes summaries of some results from previous years for completeness. The following conclusions were based on the results of various flowthrough dissolution rate tests and on tests designed to measure the inventories of {sup 129}I located within the fuel/cladding gap region of different spent fuels: (1) Spent fuels with burnups in the range 30 to 50 MWd/kgM all dissolved at about the same rate over the conditions tested. To help determine whether the lack of burnup dependence extends to higher and lower values, tests are in progress or planned for spent fuels with burnups of 13 and {approximately} 65 MWd/kgM. (2) Oxidation of spent fuel up to the U{sub 4}O{sub 9+x} stage does not have a large effect on intrinsic dissolution rates. However, this degree of oxidation could increase the dissolution rates of relatively intact fuel by opening the grain boundaries, thereby increasing the effective surface area that is available for contact by water. From a disposal viewpoint, this is a potentially more important consideration than the effect on intrinsic rates. (3) The gap inventories of {sup 129}I were found to be smaller than the fission gas release (FGR) for the same fuel rod with the exception of the rod with the highest FGR. Several additional fuels would have to be tested to determine whether a generalized relationship exists between FGR and {sup 129}I gap inventory for US LWR fuels.

  8. Flooding of a large, passive, pressure-tube LWR

    SciTech Connect

    Hejzlar, P.; Todreas, N.E.; Driscoll, M.J.

    1995-09-01

    A reactor concept has been developed which can survive LOCA without scram and without replenishing primary coolant inventory. The proposed concept is a pressure tube type reactor similar to CANDU reactors, but differing in three key aspects: (1) a solid SiC-coated graphite fuel matrix is used in place of fuel pin bundles, (2) the heavy water coolant in the pressure tubes is replaced by light water, and (3) the calandria tank contains a low pressure gas instead of heavy water moderator. The gas displaces the light water from the calandria during normal operation, while during loss of coolant or loss of heat sink accidents, it allows passive calandria flooding. This paper describes the thermal hydraulic characteristics of the gravity driven calandria flooding process. Flooding the calandria space with light water is a unique and very important feature of the proposed pressure-tube LWR concept. The flooding of the top row of fuel channels must be accomplished fast enough so that none of the critical components of the fuel channel exceed their design limits. The flooding process has been modeled and shown to be rapid enough to maintain all components within their design limits. Two other considerations are important. The thermal shock experienced by the calandria and pressure tubes has been evaluated and shown to be within acceptable bounds. Finally, although complete flooding renders the reactor deeply subcritical, various steam/water densities can be hypothesized to be present during the flooding process which could cause reactivity to increase from the initially voided calandria case. One such hypothesis which leads to the maximum possible density of the steam/water mixture in the still unflooded calandria space is entrainment from the free surface. It is shown that the steam/water mixture density yielding the maximum reactivity peak cannot be achieved by entrainment because it exceeds thermohydraulically attainable densities of steam/water by an order of magnitude.

  9. Options for Burning LWR SNF in LIFE Engine

    SciTech Connect

    Farmer, J

    2008-09-09

    We have pursued two processes in parallel for the burning of LWR SNF in the LIFE engine: (1) solid fuel option and (2) liquid fuel option. Approaches with both are discussed. The assigned Topical Report on liquid fuels is attached.

  10. New Mechanistic Pathways for Criegee-Water Chemistry at the Air/Water Interface.

    PubMed

    Zhu, Chongqin; Kumar, Manoj; Zhong, Jie; Li, Lei; Francisco, Joseph S; Zeng, Xiao Cheng

    2016-09-07

    Understanding Criegee chemistry has become one of central topics in atmospheric research recently. The reaction of Criegee intermediates with gas-phase water clusters has been widely viewed as a key Criegee reaction in the troposphere. However, the effect of aerosols or clouds on Criegee chemistry has received little attention. In this work, we have investigated the reaction between the smallest Criegee intermediate, CH2OO, and water clusters in the gas phase, as well as at the air/water surface using ab initio quantum chemical calculations and adaptive buffered force quantum mechanics/molecular mechanics (QM/MM) dynamics simulations. Our simulation results show that the typical time scale for the reaction of CH2OO with water at the air/water interface is on the order of a few picoseconds, 2-3 orders of magnitude shorter than that in the gas phase. Importantly, the adbf-QM/MM dynamics simulations suggest several reaction pathways for the CH2OO + water reaction at the air/water interface, including the loop-structure-mediated mechanism and the stepwise mechanism. Contrary to the conventional gas-phase CH2OO reaction, the loop-structure is not a prerequisite for the stepwise mechanism. For the latter, a water molecule and the CH2OO at the air/water interface, upon their interaction, can result in the formation of (H3O)(+) and (OH)CH2(OO)(-). Thereafter, a hydrogen bond can be formed between (H3O)(+) and the terminal oxygen atom of (OH)CH2(OO)(-), leading to direct proton transfer and the formation of α-hydroxy methylperoxide, HOCH2OOH. The mechanistic insights obtained from this simulation study should motivate future experimental studies of the effect of water clouds on Criegee chemistry.

  11. Rate Theory Modeling and Simulation of Silicide Fuel at LWR Conditions

    SciTech Connect

    Miao, Yinbin; Ye, Bei; Hofman, Gerard; Yacout, Abdellatif; Gamble, Kyle; Mei, Zhi-Gang

    2016-08-29

    As a promising candidate for the accident tolerant fuel (ATF) used in light water reactors (LWRs), the fuel performance of uranium silicide (U3Si2) at LWR conditions needs to be well understood. In this report, rate theory model was developed based on existing experimental data and density functional theory (DFT) calculations so as to predict the fission gas behavior in U3Si2 at LWR conditions. The fission gas behavior of U3Si2 can be divided into three temperature regimes. During steady-state operation, the majority of the fission gas stays in intragranular bubbles, whereas the dominance of intergranular bubbles and fission gas release only occurs beyond 1000 K. The steady-state rate theory model was also used as reference to establish a gaseous swelling correlation of U3Si2 for the BISON code. Meanwhile, the overpressurized bubble model was also developed so that the fission gas behavior at LOCA can be simulated. LOCA simulation showed that intragranular bubbles are still dominant after a 70 second LOCA, resulting in a controllable gaseous swelling. The fission gas behavior of U3Si2 at LWR conditions is benign according to the rate theory prediction at both steady-state and LOCA conditions, which provides important references to the qualification of U3Si2 as a LWR fuel material with excellent fuel performance and enhanced accident tolerance.

  12. LWR reactivity/isotopics code for pedagogical and scoping applications

    SciTech Connect

    AbuZaied, G.; Driscoll, M.J.

    1986-01-01

    A program designated BRICC (Burnup Reactivity and Isotopic Composition Computation), has been programmed for use on microcomputers to permit rapid parametric studies of the neutronics of light water reactor (LWR) assemblies. It is currently employed as a teaching tool in a graduate-level subject on nuclear fuel management, and has proven to be of sufficient accuracy to permit its use as a submodule in a more comprehensive program used to evaluate various mechanical spectral shift concepts for pressurized water reactor control. It should also prove useful in teaching reactor physics as it will fill an important gap between hand calculations of inadequate accuracy and state-of-the-art multigroup programs of daunting complexity. The BRICC program combines a minimum adequate set of old-fashioned phenomenological submodels that describe key physics attributed in an integral fashion, thereby providing the student or researcher with convenient mental pictures to serve as the basis for deductive reasoning. The program is short, written in a simplistic version of the Basic language, with many interspersed Remark statements, and is therefore easy to tinker with for various constructive purposes.

  13. Technical basis for hydrogen-water chemistry: Laboratory studies of water chemistry effects on SCC (stress-corrosion-cracking)

    SciTech Connect

    Kassner, T.F.; Ruther, W.E.; Soppet, W.K.

    1986-10-01

    The influence of different impurities, viz., oxyacids and several chloride salts, on the stress-corrosion-cracking (SCC) of sensitized Type 304 stainless steel (SS) was investigated in constant-extension-rate-tensile (CERT) tests in 289/sup 0/C water at a low dissolved-oxygen concentration (<5 ppB). Cyclic loading experiments on fatigue precracked fracture-mechanics-type specimens of this material and Type 316NG were also performed at 289/sup 0/C in low-oxygen environments with and without sulfate at low concentrations. In these experiments, the crack growth behavior of the materials was correlated with the type and concentration of the impurities and the electrochemical potentials of Type 304 SS and platinum electrodes in the simulated hydrogen-water chemistry environments. The information suggests that better characterization of water quality, through measurement of the concentrations of individual species (SO/sub 4//sup 2 -/, NO/sub 3//sup -/, Cu/sup 2 +/, etc.) coupled with measurements of the corrosion and redox potentials at high temperatures will provide a viable means to monitor and ultimately improve the performance of BWR system materials.

  14. Photosynthetic water oxidation: insights from manganese model chemistry.

    PubMed

    Young, Karin J; Brennan, Bradley J; Tagore, Ranitendranath; Brudvig, Gary W

    2015-03-17

    Catalysts for light-driven water oxidation are a critical component for development of solar fuels technology. The multielectron redox chemistry required for this process has been successfully deployed on a global scale in natural photosynthesis by green plants and cyanobacteria using photosystem II (PSII). PSII employs a conserved, cuboidal Mn4CaOX cluster called the O2-evolving complex (OEC) that offers inspiration for artificial O2-evolution catalysts. In this Account, we describe our work on manganese model chemistry relevant to PSII, particularly the functional model [Mn(III/IV)2(terpy)2(μ-O)2(OH2)2](NO3)3 complex (terpy = 2,2';6',2″-terpyridine), a mixed-valent di-μ-oxo Mn dimer with two terminal aqua ligands. In the presence of oxo-donor oxidants such as HSO5(-), this complex evolves O2 by two pathways, one of which incorporates solvent water in an O-O bond-forming reaction. Deactivation pathways of this catalyst include comproportionation to form an inactive Mn(IV)Mn(IV) dimer and also degradation to MnO2, a consequence of ligand loss when the oxidation state of the complex is reduced to labile Mn(II) upon release of O2. The catalyst's versatility has been shown by its continued catalytic activity after direct binding to the semiconductor titanium dioxide. In addition, after binding to the surface of TiO2 via a chromophoric linker, the catalyst can be oxidized by a photoinduced electron-transfer mechanism, mimicking the natural PSII process. Model oxomanganese complexes have also aided in interpreting biophysical and computational studies on PSII. In particular, the μ-oxo exchange rates of the Mn-terpy dimer have been instrumental in establishing that the time scale for μ-oxo exchange of high-valent oxomanganese complexes with terminal water ligands is slower than O2 evolution in the natural photosynthetic system. Furthermore, computational studies on the Mn-terpy dimer and the OEC point to similar Mn(IV)-oxyl intermediates in the O-O bond

  15. Water at surfaces with tunable surface chemistries and the chiral imprint of water around DNA

    NASA Astrophysics Data System (ADS)

    Petersen, Poul

    Aqueous interfaces are ubiquitous in atmospheric chemistry and biological systems but are notoriously hard to probe experimentally. Surface-specific vibrational spectroscopy offers an avenue to directly probe the vibrational modes of the water OH stretching band but this method is challenging to implement to buried surfaces. Here we present results from sum-frequency generation (SFG) spectroscopy probing the buried interface between a functionalized surface and aqueous solutions. Studying such buried surfaces offers the advantage of being able to systematically tune the surface chemistry using self-assembled monolayers, i.e. the hydrophobic and hydrophilic character, and examine the effect on the interfacial water. In addition to water at these controlled surfaces, we have initiated studying water at biological surfaces. This includes the solvation structure around DNA. X-ray experiments at cryogenic temperatures have found crystallographic water in the minor grove of DNA giving rise to the notion of a spine of hydration surrounding DNA. Such structured water should exhibit a chiral structure adapted from DNA. We investigate if such a chiral water structure exist around DNA at room temperature using chiral SFG. This work was supported by the National Science Foundation under a NSF CAREER Grant (CHE-1151079).

  16. Diagnostic tools for mixing models of stream water chemistry

    USGS Publications Warehouse

    Hooper, R.P.

    2003-01-01

    Mixing models provide a useful null hypothesis against which to evaluate processes controlling stream water chemical data. Because conservative mixing of end-members with constant concentration is a linear process, a number of simple mathematical and multivariate statistical methods can be applied to this problem. Although mixing models have been most typically used in the context of mixing soil and groundwater end-members, an extension of the mathematics of mixing models is presented that assesses the "fit" of a multivariate data set to a lower dimensional mixing subspace without the need for explicitly identified end-members. Diagnostic tools are developed to determine the approximate rank of the data set and to assess lack of fit of the data. This permits identification of processes that violate the assumptions of the mixing model and can suggest the dominant processes controlling stream water chemical variation. These same diagnostic tools can be used to assess the fit of the chemistry of one site into the mixing subspace of a different site, thereby permitting an assessment of the consistency of controlling end-members across sites. This technique is applied to a number of sites at the Panola Mountain Research Watershed located near Atlanta, Georgia.

  17. Patterns of spatial autocorrelation in stream water chemistry.

    PubMed

    Peterson, Erin E; Merton, Andrew A; Theobald, David M; Urquhart, N Scott

    2006-10-01

    Geostatistical models are typically based on symmetric straight-line distance, which fails to represent the spatial configuration, connectivity, directionality, and relative position of sites in a stream network. Freshwater ecologists have explored spatial patterns in stream networks using hydrologic distance measures and new geostatistical methodologies have recently been developed that enable directional hydrologic distance measures to be considered. The purpose of this study was to quantify patterns of spatial correlation in stream water chemistry using three distance measures: straight-line distance, symmetric hydrologic distance, and weighted asymmetric hydrologic distance. We used a dataset collected in Maryland, USA to develop both general linear models and geostatistical models (based on the three distance measures) for acid neutralizing capacity, conductivity, pH, nitrate, sulfate, temperature, dissolved oxygen, and dissolved organic carbon. The spatial AICC methodology allowed us to fit the autocorrelation and covariate parameters simultaneously and to select the model with the most support in the data. We used the universal kriging algorithm to generate geostatistical model predictions. We found that spatial correlation exists in stream chemistry data at a relatively coarse scale and that geostatistical models consistently improved the accuracy of model predictions. More than one distance measure performed well for most chemical response variables, but straight-line distance appears to be the most suitable distance measure for regional geostatistical modeling. It may be necessary to develop new survey designs that more fully capture spatial correlation at a variety of scales to improve the use of weighted asymmetric hydrologic distance measures in regional geostatistical models.

  18. Effects of handling, temperature and storage time on sediment and pore-water chemistry and toxicity

    SciTech Connect

    Lasier, P.J.; Winger, P.V.; Jackson, B.P.

    1994-12-31

    Effects of sediment disturbance, storage temperature (230 C and 40 C) and storage time on chemistry and toxicity of sediment and pore water were evaluated using two sediments (sandy freshwater and organic estuarine) contaminated with metals. Solid-phase (10 d with water renewal) and pore-water (96-h static) toxicity tests with Hyalella azteca were conducted upon collection and at two week intervals for 8--10 weeks. Chemistries (redox, pH, conductivity, alkalinity, ammonia, trace metals, major cations and anions) were measured at each toxicity testing interval. Following extraction, pore-water chemistry changed significantly during the initial 96 h due to oxidation reactions and CO{sub 2} equilibration. Pore water collected in situ was slightly less toxic and had major differences in water chemistry compared to pore water extracted from homogenized sediment. Storage temperature and time significantly influenced pore-water toxicity and chemistry, but had minimal effect on solid-phase toxicity. After four weeks, the highly-toxic sandy sediment became slightly less toxic in solid-phase tests and Significantly less toxic in pore-water tests, coinciding with changes in trace-metal concentrations, activities, and speciation. The estuarine sediment became slightly more toxic in both solid-phase and pore-water tests after four weeks, but returned to original levels after six and eight weeks. Sediment disturbance, storage temperature, and storage time significantly influenced toxicity and pore-water chemistry.

  19. Multiscale Modeling of Chemistry in Water: Are We There Yet?

    PubMed

    Bulo, Rosa E; Michel, Carine; Fleurat-Lessard, Paul; Sautet, Philippe

    2013-12-10

    This paper critically evaluates the state of the art in combined quantum mechanical/molecular mechanical (QM/MM) approaches to the computational description of chemistry in water and supplies guidelines for the setup of customized multiscale simulations of aqueous processes. We differentiate between structural and dynamic performance, since some tasks, e.g., the reproduction of NMR or UV-vis spectra, require only structural accuracy, while others, i.e., reaction mechanisms, require accurate dynamic data as well. As a model system for aqueous solutions in general, the approaches were tested on a QM water cluster in an environment of MM water molecules. The key difficulty is the description of the possible diffusion of QM molecules into the MM region and vice versa. The flexible inner region ensemble separator (FIRES) approach constrains QM solvent molecules within an active (QM) region. Sorted adaptive partitioning (SAP), difference-based adaptive solvation (DAS), and buffered-force (BF) are all adaptive approaches that use a buffer zone in which solvent molecules gradually adapt from QM to MM (or vice versa). The costs of SAP and DAS are relatively high, while BF is fast but sacrifices conservation of both energy and momentum. Simulations in the limit of an infinitely small buffer zone, where DAS and SAP become equivalent, are discussed as well and referred to as ABRUPT. The best structural accuracy is obtained with DAS, BF, and ABRUPT, all three of similar quality. FIRES performs very well for dynamic properties localized deep within the QM region. By means of elimination DAS emerges as the best overall compromise between structural and dynamic performance. Eliminating the buffer zone (ABRUPT) improves efficiency and still leads to surprisingly good results. While none of the many new flavors are perfect, all together this new field already allows accurate description of a wide range of structural and dynamic properties of aqueous solutions.

  20. Water chemistry controlled aggregation and photo-transformation of silver nanoparticles in environmental waters.

    PubMed

    Yin, Yongguang; Yang, Xiaoya; Zhou, Xiaoxia; Wang, Weidong; Yu, Sujuan; Liu, Jingfu; Jiang, Guibin

    2015-08-01

    The inevitable release of engineered silver nanoparticles (AgNPs) into aquatic environments has drawn great concerns about its environmental toxicity and safety. Although aggregation and transformation play crucial roles in the transport and toxicity of AgNPs, how the water chemistry of environmental waters influences the aggregation and transformation of engineered AgNPs is still not well understood. In this study, the aggregation of polyvinylpyrrolidone (PVP) coated AgNPs was investigated in eight typical environmental water samples (with different ionic strengths, hardness, and dissolved organic matter (DOM) concentrations) by using UV-visible spectroscopy and dynamic light scattering. Raman spectroscopy was applied to probe the interaction of DOM with the surface of AgNPs. Further, the photo-transformation and morphology changes of AgNPs in environmental waters were studied by UV-visible spectroscopy, inductively coupled plasma mass spectrometry, and transmission electron microscopy. The results suggested that both electrolytes (especially Ca(2+) and Mg(2+)) and DOM in the surface waters are key parameters for AgNP aggregation, and sunlight could accelerate the morphology change, aggregation, and further sedimentation of AgNPs. This water chemistry controlled aggregation and photo-transformation should have significant environmental impacts on the transport and toxicity of AgNPs in the aquatic environments.

  1. Preliminary investigation of the /sup 252/Cf-source-driven noise analysis method of subcriticality measurement in LWR fuel storage and initial loading applications

    SciTech Connect

    King, W.T.; Mihalczo, J.T.; Blakeman, E.D.

    1984-01-01

    The ability of the /sup 252/Cf-source-driven neutron noise analysis method to measure subcriticality has been demonstrated in a variety of experimental configurations of fissile materials. Calculations for an approximately 4-m-dia configuration of light water reactor (LWR) fuel elements indicated the feasibility of measuring the subcriticality of large, loosely coupled arrays of LWR fuel elements by this same method. These analysis suggested application to the initial loading of both pressurized and boiling water reactors, zero-power testing of reactors (such as shutdown margin measurements after initial loading), light water reactor refueling, and safe storage of LWR spent fuel. In the fuel storage application, direct measurement of subcriticality in the actual fuel storage facilities provides the parameter which is directly related to criticality safety.

  2. Ground-water and water-chemistry data for the Willamette basin, Oregon

    USGS Publications Warehouse

    Orzol, Leonard L.; Wozniak, Karl C.; Meissner, Tiffany R.; Lee, Douglas B.

    2000-01-01

    This report presents ground-water data collected and compiled as part of a study of the ground-water resources of the Willamette River Basin, Oregon. The report includes tabulated information and a location map for 1,234 field-located water wells and 6 springs, hydrographs showing water-level fluctuations during various time periods for 265 of the wells, borehole geophysical data for 16 wells, and water-chemistry analyses from 125 wells and 6 springs. These data, as well as data for 4,752 additional fieldlocated wells and 1 spring, are included on a CD-ROM. In addition, the locations of the field-located wells and springs are provided in geographic information system formats on the CD-ROM.

  3. The Effect of Water Chemistry on the Removal of Arsenic from Drinking Water During Iron Removal Treatment

    EPA Science Inventory

    This research investigates the effects of water chemistry, oxidant type and concentration on the removal of iron and arsenic from drinking water. The research will be conducted using one of the National Risk Management Research Laboratory’s Water Supply and Water Resources Divisi...

  4. The Effect of Water Chemistry on the Removal of Arsenic from Drinking Water During Iron Removal Treatment

    EPA Science Inventory

    This research investigates the effects of water chemistry, oxidant type and concentration on the removal of iron and arsenic from drinking water. The research will be conducted using one of the National Risk Management Research Laboratory’s Water Supply and Water Resources Divisi...

  5. Optimization of the water chemistry of the primary coolant at nuclear power plants with VVER

    SciTech Connect

    Barmin, L. F.; Kruglova, T. K.; Sinitsyn, V. P.

    2005-01-15

    Results of the use of automatic hydrogen-content meter for controlling the parameter of 'hydrogen' in the primary coolant circuit of the Kola nuclear power plant are presented. It is shown that the correlation between the 'hydrogen' parameter in the coolant and the 'hydrazine' parameter in the makeup water can be used for controlling the water chemistry of the primary coolant system, which should make it possible to optimize the water chemistry at different power levels.

  6. Produced water chemistry data for samples from four petroleum wells, Southern San Joaquin Valley, California, 2014

    USGS Publications Warehouse

    Davis, Tracy A.; Kulongoski, Justin; McMahon, Peter B.

    2016-01-01

    The U.S. Geological Survey (USGS) in cooperation with the California State Water Resources Control Board collected produced water samples from four petroleum wells in the southern San Joaquin Valley on November 5, 2014. This digital dataset contains the site information, analyzing laboratories and methods, and water chemistry and quality control results for these samples. Water chemistry results include concentrations of dissolved hydrocarbon gases and their isotopic composition; concentrations of inorganic constituents including salinity, major ions, and nutrients; dissolved organic carbon; and stable isotopes of water and strontium dissolved in water. Samples were analyzed by 5 laboratories operated or contracted by the USGS.

  7. EUV resist curing technique for LWR reduction and etch selectivity enhancement

    NASA Astrophysics Data System (ADS)

    Narishige, Kazuki; Katsunuma, Takayuki; Honda, Masanobu; Yatsuda, Koichi

    2012-03-01

    This paper introduces a new technique utilizing a direct current superimposed (DCS) capacitively-coupled plasma (CCP) to enhance the etch selectivity to EUV resist with decreasing line width roughness (LWR). This new technique includes chemical and e-beam curing effects. DCS CCP generates ballistic electrons, which reform the chemical structure of photoresist. This surface modification hardens the photoresist (PR), and enhances the etch selectivity. The PR-hardening technique also improves the tolerance towards stress by polymer. Hence, a polymer becomes applicable to protect photoresist, and the etch selectivity increases even more. As a result, this cure can be processed without consuming the thickness of EUV resist. The mechanism of EUV resist cure is discussed based on the surface analysis. In addition to the basic physics of PR-hardening, this paper shows the benchmark results between DCS CCP and the conventional curing techniques by RIE, such as HBr cure and H2 cure. Several new chemistries were applied to DCS CCP. In consequence, the PR-hardening by DCS CCP achieved a 33% reduction in LWR at pre-etch treatment, and a 30% reduction during under layer etch simultaneously maintaining enough thickness of EUV resist.

  8. Fully Ceramic Microencapsulated Fuel Development for LWR Applications

    SciTech Connect

    Snead, Lance Lewis; Besmann, Theodore M; Terrani, Kurt A; Voit, Stewart L

    2012-01-01

    The concept, fabrication, and key feasibility issues of a new fuel form based on the microencapsulated (TRISO-type) fuel which has been specifically engineered for LWR application and compacted within a SiC matrix will be presented. This fuel, the so-called fully ceramic microencapsulated fuel is currently undergoing development as an accident tolerant fuel for potential UO2 replacement in commercial LWRs. While the ability of this fuel to facilitate normal LWR cycle performance is an ongoing effort within the program, this will not be a focus of this paper. Rather, key feasibility and performance aspects of the fuel will be presented including the ability to fabricate a LWR-specific TRISO, the need for and route to a high thermal conductivity and fully dense matrix that contains neutron poisons, and the performance of that matrix under irradiation and the interaction of the fuel with commercial zircaloy clad.

  9. Enhanced Accident Tolerant LWR Fuels National Metrics Workshop Report

    SciTech Connect

    Lori Braase

    2013-01-01

    The U.S. Department of Energy Office of Nuclear Energy (DOE-NE), in collaboration with the nuclear industry, has been conducting research and development (R&D) activities on advanced Light Water Reactor (LWR) fuels for the last few years. The emphasis for these activities was on improving the fuel performance in terms of increased burnup for waste minimization and increased power density for power upgrades, as well as collaborating with industry on fuel reliability. After the events at the Fukushima Nuclear Power Plant in Japan in March 2011, enhancing the accident tolerance of LWRs became a topic of serious discussion. In the Consolidated Appropriations Act, 2012, Conference Report 112-75, the U.S. Congress directed DOE-NE to: • Give “priority to developing enhanced fuels and cladding for light water reactors to improve safety in the event of accidents in the reactor or spent fuel pools.” • Give “special technical emphasis and funding priority…to activities aimed at the development and near-term qualification of meltdown-resistant, accident-tolerant nuclear fuels that would enhance the safety of present and future generations of light water reactors.” • Report “to the Committee, within 90 days of enactment of this act, on its plan for development of meltdown-resistant fuels leading to reactor testing and utilization by 2020.” Fuels with enhanced accident tolerance are those that, in comparison with the standard UO2-zirconium alloy system currently used by the nuclear industry, can tolerate loss of active cooling in the reactor core for a considerably longer time period (depending on the LWR system and accident scenario) while maintaining or improving the fuel performance during normal operations, and operational transients, as well as design-basis and beyond design-basis events. The overall draft strategy for development and demonstration is comprised of three phases: Feasibility Assessment and Down-selection; Development and Qualification; and

  10. Just Add Water and Stir. Graduate Chemistry Laboratory, Stony Brook

    ERIC Educational Resources Information Center

    Yee, Roger

    1974-01-01

    Using traditional building materials and a fast-track recipe, the architects, acting as construction manager, completed the Graduate Chemistry Laboratory at Stony Brook, New York, two full years ahead of schedule. (Author/MF)

  11. Improved LWR Cladding Performance by EPD Surface Modification Technique

    SciTech Connect

    Corradini, Michael; Sridharan, Kumar

    2012-11-26

    This project will utilize the electro-phoretic deposition technique (EPD) in conjunction with nanofluids to deposit oxide coatings on prototypic zirconium alloy cladding surfaces. After demonstrating that this surface modification is reproducible and robust, the team will subject the modified surface to boiling and corrosion tests to characterize the improved nucleate boiling behavior and superior corrosion performance. The scope of work consists of the following three tasks: The first task will employ the EPD surface modification technique to coat the surface of a prototypic set of zirconium alloy cladding tube materials (e.g. Zircaloy and advanced alloys such as M5) with a micron-thick layer of zirconium oxide nanoparticles. The team will characterize the modified surface for uniformity using optical microscopy and scanning-electron microscopy, and for robustness using standard hardness measurements. After zirconium alloy cladding samples have been prepared and characterized using the EPD technique, the team will begin a set of boiling experiments to measure the heat transfer coefficient and critical heat flux (CHF) limit for each prepared sample and its control sample. This work will provide a relative comparison of the heat transfer performance for each alloy and the surface modification technique employed. As the boiling heat transfer experiments begin, the team will also begin corrosion tests for these zirconium alloy samples using a water corrosion test loop that can mimic light water reactor (LWR) operational environments. They will perform extended corrosion tests on the surface-modified zirconium alloy samples and control samples to examine the robustness of the modified surface, as well as the effect on surface oxidation

  12. Effect of water chemistry on disinfection by-product formation in the complex surface water system.

    PubMed

    Hao, Rongjie; Zhang, Yan; Du, Tingting; Yang, Li; Adeleye, Adeyemi S; Li, Yao

    2017-04-01

    The relationship between the disinfection by-products (DBPs) formed with chlorination and chloramination techniques and the water chemistry of Haihe River was compared. Samples were collected at 28 different points within the mainstream and tributaries of the river. The DBPs investigated include trihalomethanes (THMs), haloacetic acids (HAAs), haloacetonitriles (HANs), haloketones (HKs), and trichloronitromethane. THMs formed when the samples were chlorinated mostly exceeded 100 and 600 μg/L in the mainstream and tributaries and in the estuary, respectively. A similar trend was obtained for HAAs whose concentrations exceeded 150 μg/L in almost all samples. The amounts of DBPs formed when the samples were chloraminated were much lower than when chlorination was used. The concentrations and species of THMs and HAAs in samples collected from sites near the estuary were different from those in samples collected from the mainstream, which may be due to high concentrations of Cl(-) and Br(-). Although natural organic matter is the major cause of DBP formation during water disinfection, this study shows that other water chemistry factors such as salt composition and concentrations may also considerably affect the formation of DBPs in natural aquatic systems. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Ground-water, surface-water, and water-chemistry data, Black Mesa area, northeastern Arizona, 1997

    USGS Publications Warehouse

    Littin, Gregory R.; Baum, Bradley M.; Truini, Margot

    1999-01-01

    The Black Mesa monitoring program is designed to document long-term effects of ground-water from the N aquifer by industrial and municipal users. The N aquifer is the major source of water in the 5,400-square-mile Black Mesa area, and the ground water occurs under confined and unconfined conditions. Monitoring activities include continuous and periodic measurements of (1) ground-water pumpage from the confined and unconfined parts of the aquifer, (2) ground-water levels in the confined and unconfined parts of the aquifer, (3) surface-water discharge, and (4) chemistry of the ground water and surface water. In 1997, ground-water withdrawals for industrial and municipal use totaled about 7,090 acre-feet, which is less than a 1-percent increase from 1996. Pumpage from the confined part of the aquifer increased by about 2 percent to 5,510 acre-feet, and pumpage from the unconfined part of the aquifer decreased by about 4 percent to 1,580 acre-feet. Water-level declines in the confined part during 1997 were recorded in 5 of 12 wells; however, the median change was a rise of about 0.2 foot as opposed to a decline of 2.8 feet for 1996. Water-level declines in the unconfined part were recorded in 7 of 15 wells, and the median change was 0.0 foot in 1997 as opposed to a decline of 0.5 foot in 1996. The low-flow discharge at the Moenkopi streamflow-gaging station ranged from 1.6 to 2.0 cubic feet per second in 1997. Streamflow-discharge measurements also were made at Laguna Creek, Dinnebito Wash, and Polacca Wash during 1997. The low-flow discharge ranged from 2.3 to 4.2 cubic feet per second at Laguna Creek, 0.44 to 0.48 cubic foot per second at Dinnebito Wash, and 0.15 to 0.26 cubic foot per second at Polacca Wash. Discharge was measured at three springs. Discharge from Moenkopi School Spring increased by about 3 gallons per minute from the measurement in 1996. Discharge from an unnamed spring near Dennehotso increased by 9.9 gallons per minute from the measurement made in

  14. Water chemistry of the secondary circuit at a nuclear power station with a VVER power reactor

    NASA Astrophysics Data System (ADS)

    Tyapkov, V. F.; Erpyleva, S. F.

    2017-05-01

    Results of implementation of the secondary circuit organic amine water chemistry at Russian nuclear power plant (NPP) with VVER-1000 reactors are presented. The requirements for improving the reliability, safety, and efficiency of NPPs and for prolonging the service life of main equipment items necessitate the implementation of new technologies, such as new water chemistries. Data are analyzed on the chemical control of power unit coolant for quality after the changeover to operation with the feed of higher amines, such as morpholine and ethanolamine. Power units having equipment containing copper alloy components were converted from the all-volatile water chemistry to the ethanolamine or morpholine water chemistry with no increase in pH of the steam generator feedwater. This enables the iron content in the steam generator feedwater to be decreased from 6-12 to 2.0-2.5 μg/dm3. It is demonstrated that pH of high-temperature water is among the basic factors controlling erosion and corrosion wear of the piping and the ingress of corrosion products into NPP steam generators. For NPP power units having equipment whose construction material does not include copper alloys, the water chemistries with elevated pH of the secondary coolant are adopted. Stable dosing of correction chemicals at these power units maintains pH25 of 9.5 to 9.7 in the steam generator feedwater with a maximum iron content of 2 μg/dm3 in the steam generator feedwater.

  15. Groundwater, surface-water, and water-chemistry data from C-aquifer monitoring program, northeastern Arizona, 2005-11

    USGS Publications Warehouse

    Brown, Christopher R.; Macy, Jamie P.

    2012-01-01

    Water-chemistry data for selected wells and baseflow investigations sites are presented. No well samples analyzed exceeded the U.S. Environmental Protection Agency Maximum Contaminant Level standards for drinking water, but several samples exceeded Secondary Maximum Contaminant Level standards for chloride, fluoride, sulfate, iron, and total dissolved solids.

  16. Water chemistry of surface waters affected by the Fourmile Canyon wildfire, Colorado, 2010-2011

    USGS Publications Warehouse

    McCleskey, R. Blaine; Writer, Jeffrey H.; Murphy, Sheila F.

    2012-01-01

    In September 2010, the Fourmile Canyon fire burned about 23 percent of the Fourmile Creek watershed in Boulder County, Colo. Water-quality sampling of Fourmile Creek began within a month after the wildfire to assess its effects on surface-water chemistry. Water samples were collected from five sites along Fourmile Creek (above, within, and below the burned area) monthly during base flow, twice weekly during snowmelt runoff, and at higher frequencies during storm events. Stream discharge was also monitored. Water-quality samples were collected less frequently from an additional 6 sites on Fourmile Creek, from 11 tributaries or other inputs, and from 3 sites along Boulder Creek. The pH, electrical conductivity, temperature, specific ultraviolet absorbance, total suspended solids, and concentrations (dissolved and total) of major cations (calcium, magnesium, sodium, and potassium), anions (chloride, sulfate, alkalinity, fluoride, and bromide), nutrients (nitrate, ammonium, and phosphorus), trace metals (aluminum, arsenic, boron, barium, beryllium, cadmium, cobalt, chromium, copper, iron, mercury, lithium, manganese, molybdenum, nickel, lead, rubidium, antimony, selenium, strontium, vanadium, and zinc), and dissolved organic carbon are here reported for 436 samples collected during 2010 and 2011.

  17. An Environmental Chemistry Experiment: The Determination of Radon Levels in Water.

    ERIC Educational Resources Information Center

    Welch, Lawrence E.; Mossman, Daniel M.

    1994-01-01

    Describes a radiation experiment developed to complement a new environmental chemistry laboratory curriculum. A scintillation counter is used to measure radon in water. The procedure relies on the fact that toluene will preferentially extract radon from water. Sample preparation is complete in less than 90 minutes. Because the level of…

  18. The influence of water chemistries on Flavobacterium columnare pathogenesis in channel catfish

    USDA-ARS?s Scientific Manuscript database

    Columnaris disease can cause tremendous losses of freshwater fish. While it has been studied exhaustively, little is known about its affinity to specific water chemistries that affects attachment. Recent studies in our labs have illuminated this subject. In the first experiment, two waters were u...

  19. Fine scale variations of surface water chemistry in an ephemeral to perennial drainage network

    Treesearch

    Margaret A. Zimmer; Scott W. Bailey; Kevin J. McGuire; Thomas D. Bullen

    2013-01-01

    Although temporal variation in headwater stream chemistry has long been used to document baseline conditions and response to environmental drivers, less attention is paid to fine scale spatial variations that could yield clues to processes controlling stream water sources. We documented spatial and temporal variation in water composition in a headwater catchment (41 ha...

  20. The hydrochemistry of glacial Ebba River (Petunia Bay, Central Spitsbergen): Groundwater influence on surface water chemistry

    NASA Astrophysics Data System (ADS)

    Dragon, Krzysztof; Marciniak, Marek; Szpikowski, Józef; Szpikowska, Grażyna; Wawrzyniak, Tomasz

    2015-10-01

    The article presents the investigation of surface water chemistry changes of the glacial Ebba River (Central Spitsbergen) during three melting seasons of 2008, 2009 and 2010. The twice daily water chemistry analyses allow recognition of the surface water chemistry differentiation. The surface water chemistry changes are related to the river discharge and changes in the influence of different water balance components during each melting season. One of the most important process that influence river water component concentration increase is groundwater inflow from active layer occurring on the valley area. The significance of this process is the most important at the end of the melting season when temperatures below 0 °C occur on glaciers (resulting in a slowdown of melting of ice and snow and a smaller recharge of the river by the water from the glaciers) while the flow of groundwater is still active, causing a relatively higher contribution of groundwater to the total river discharge. The findings presented in this paper show that groundwater contribution to the total polar river water balance is more important than previously thought and its recognition allow a better understanding of the hydrological processes occurring in a polar environment.

  1. An Environmental Chemistry Experiment: The Determination of Radon Levels in Water.

    ERIC Educational Resources Information Center

    Welch, Lawrence E.; Mossman, Daniel M.

    1994-01-01

    Describes a radiation experiment developed to complement a new environmental chemistry laboratory curriculum. A scintillation counter is used to measure radon in water. The procedure relies on the fact that toluene will preferentially extract radon from water. Sample preparation is complete in less than 90 minutes. Because the level of…

  2. Ground-water, surface-water, and water-chemistry data, Black Mesa area, northeastern Arizona, 1996

    USGS Publications Warehouse

    Littin, Gregory R.; Monroe, Stephen A.

    1997-01-01

    The Black Mesa monitoring program is designed to document long-term effects of ground-water pumping from the N aquifer by industrial and municipal users. The N aquifer is the major source of water in the 5,400-square-mile Black Mesa area, and the ground water occurs under confined and unconfined conditions. Monitoring activities include continuous and periodic measurements of (1) ground-water pumpage from the confined and unconfined parts of the aquifer, (2) ground-water levels in the confined and unconfined areas of the aquifer, (3) surface-water discharge, and (4) chemistry of the ground water and surface water. In 1996, ground-water withdrawals for industrial and municipal use totaled about 7,040 acre-feet, which is less than a 1-percent decrease from 1995. Pumpage from the confined part of the aquifer decreased by about 3 percent to 5,390 acre-feet, and pumpage from the unconfined part of the aquifer increased by about 9 percent to 1,650 acre-feet. Water-level declines in the confined area during 1996 were recorded in 11 of 13 wells, and the median change was a decline of about 2.7 feet as opposed to a decline of 1.8 feet for 1995. Water-level declines in the unconfined area were recorded in 11 of 18 wells, and the median change was a decline of 0.5 foot in 1996 as opposed to a decline of 0.1 foot in 1995. The average low-flow discharge at the Moenkopi streamflow-gaging station was 2.3 cubic feet per second in 1996. Streamflow-discharge measurements also were made at Laguna Creek, Dinnebito Wash, and Polacca Wash during 1996. Average low-flow discharge was 2.3 cubic feet per second at Laguna Creek, 0.4 cubic foot per second at Dinnebito Wash, and 0.2 cubic foot per second at Polacca Wash. Discharge was measured at three springs. Discharge from Moenkopi School Spring decreased by about 2 gallons per minute from the measurement in 1995. Discharge from an unnamed spring near Dennehotso decreased by 1.3 gallons per minute from the measurement made in 1995; however

  3. Interstellar Ice Chemistry: From Water to Complex Organics

    NASA Astrophysics Data System (ADS)

    Oberg, Karin I.; Fayolle, E.; Linnartz, H.; van Dishoeck, E.; Fillion, J.; Bertin, M.

    2013-06-01

    Molecular cloud cores, protostellar envelopes and protoplanetary disk midplanes are all characterized by freeze-out of atoms and molecules (other than H and H2) onto interstellar dust grains. On the grain surface, atom addition reactions, especially hydrogenation, are efficient and H2O forms readily from O, CH3OH from CO etc. The result is an icy mantle typically dominated by H2O, but also rich in CO2, CO, NH3, CH3OH and CH4. These ices are further processed through interactions with radiation, electrons and energetic particles. Because of the efficiency of the freeze-out process, and the complex chemistry that succeeds it, these icy grain mantles constitute a major reservoir of volatiles during star formation and are also the source of much of the chemical evolution observed in star forming regions. Laboratory experiments allow us to explore how molecules and radicals desorb, dissociate, diffuse and react in ices when exposed to different sources of energy. Changes in ice composition and structure is constrained using infrared spectroscopy and mass spectrometry. By comparing ice desorption, segregation, and chemistry efficiencies under different experimental conditions, we can characterize the basic ice processes, e.g. diffusion of different species, that underpin the observable changes in ice composition and structure. This information can then be used to predict the interstellar ice chemical evolution. I will review some of the key laboratory discoveries on ice chemistry during the past few years and how they have been used to predict and interpret astronomical observations of ice bands and gas-phase molecules associated with ice evaporation. These include measurements of thermal diffusion in and evaporation from ice mixtures, non-thermal diffusion efficiencies (including the recent results on frequency resolved UV photodesorption), and the expected temperature dependencies of the complex ice chemistry regulated by radical formation and diffusion. Based on these

  4. Application of the organic on water reactions to prebiotic chemistry

    NASA Astrophysics Data System (ADS)

    Kolb, Vera M.

    2012-10-01

    The old view that prebiotic reactions in water are hampered by the low solubility of the organic compounds in water is now being revised due to the discoveries of the reactions "on water". These reactions occur in the heterogeneous system comprising of the organic compounds and water. Unexpectedly, such reactions are extremely efficient; they often give quantitative yields, and are accelerated in the presence of water as compared to the organic solvents. These "on water" reactions are not the same as the "in water" reactions, which occur in solution, and are thus homogenous. Examples of the "on water" reactions include Diels-Alder, Claisen, Passerini and Ugi reactions, among many others. Some of these reactions are multicomponent, but give a single product. We survey a selected number of the "on water" reactions, which have a potential prebiotic applications.

  5. Spatial organization of stream water discharge and chemistry in forested headwaters

    NASA Astrophysics Data System (ADS)

    Egusa, T.; Ohte, N.; Oda, T.; Suzuki, M.

    2013-12-01

    It has long been known that, in small catchments, stream water discharge and chemistry are highly variable but the variability decreases gradually with an increase in the catchment area. Wood et al. (1988) showed that model calculations of infiltration and the runoff rate became constant above a certain threshold area. They defined the threshold area as the representative elementary area (REA) and stated that above the REA only minimum knowledge of the underlying parameters is needed to explain the stream water discharge and chemistry. Subsequently, empirical studies were conducted in several catchments. These studies all verified the existence of an REA in real catchments and indicated that the REA values differed among catchments. The results also suggested that the confluence processes of stream water discharge and chemistry differed among catchments. However, it has not been clarified how the confluence processes behave and why processes differ among catchments. One of the unclear things to resolve is whether the variability of discharge and chemistry among small catchments can be regarded as randomness or if it is organized. Two previous studies examined it and reported the opposite results. Woods et al. (1995) reported that organization was apparent from their observations of specific discharge. However, Asano and Uchida (2010) stated that their results for SiO2 could be regarded as randomness. These studies targeted different observed items and different catchments. Therefore, general knowledge about organization of stream water discharge and chemistry has not been obtained. We observed spatial variability of stream water discharge and chemistry and examined the existence of spatial organization by using the statistical method. Our objective was to elucidate whether the spatial organization exists about stream water discharge and chemistry. Observations were conducted in three forested catchments in Japan. Snapshot samplings of stream water discharge and

  6. Variance in water chemistry parameters in isolated wetlands of Florida, USA, and relationships with macroinvertebrate and diatom community structure

    EPA Science Inventory

    Eighty small isolated wetlands throughout Florida were sampled in 2005 to explore within-site variability of water chemistry parameters and relate water chemistry to macroinvertebrate and diatom community structure. Three samples or measures of water were collected within each si...

  7. Variance in water chemistry parameters in isolated wetlands of Florida, USA, and relationships with macroinvertebrate and diatom community structure

    EPA Science Inventory

    Eighty small isolated wetlands throughout Florida were sampled in 2005 to explore within-site variability of water chemistry parameters and relate water chemistry to macroinvertebrate and diatom community structure. Three samples or measures of water were collected within each si...

  8. Chemistry of spring and well waters on Kilauea Volcano, Hawaii, and vicinity

    SciTech Connect

    Janik, C.J.; Nathenson, M.; Scholl, M.A.

    1994-12-31

    Published and new data for chemical and isotopic samples from wells and springs on Kilauea Volcano and vicinity are presented. These data are used to understand processes that determine the chemistry of dilute meteoric water, mixtures with sea water, and thermal water. Data for well and spring samples of non-thermal water indicate that mixing with sea water and dissolution of rock from weathering are the major processes that determine the composition of dissolved constituents in water. Data from coastal springs demonstrate that there is a large thermal system south of the lower east rift of Kilauea. Samples of thermal water from shallow wells in the lower east rift and vicinity have rather variable chemistry indicating that a number of processes operate in the near surface. Water sampled from the available deep wells is different in composition from the shallow thermal water, indicating that generally there is not a significant component of deep water in the shallow wells. Data for samples from available deep wells show significant gradients in chemistry and steam content of the reservoir fluid. These gradients are interpreted to indicate that the reservoir tapped by the existing wells is an evolving vapor-dominated system.

  9. Water and Life in the International Year of Chemistry

    ERIC Educational Resources Information Center

    Bernal, Pedro J.

    2011-01-01

    This commentary talks about the worldwide health impact of lack of access to potable water. Household water treatment and storage (HWTS) is described as one approach to improving potable water accessibility in which students and educators can make a contribution to alleviate the problem of lack of access. The author suggests that, as chemists,…

  10. Water and Life in the International Year of Chemistry

    ERIC Educational Resources Information Center

    Bernal, Pedro J.

    2011-01-01

    This commentary talks about the worldwide health impact of lack of access to potable water. Household water treatment and storage (HWTS) is described as one approach to improving potable water accessibility in which students and educators can make a contribution to alleviate the problem of lack of access. The author suggests that, as chemists,…

  11. Chemistry of water collected from an unventilated drift, Yucca Mountain, Nevada

    USGS Publications Warehouse

    Marshall, B.D.; Oliver, T.A.; Peterman, Z.E.

    2007-01-01

    Water samples (referred to as puddle water samples) were collected from the surfaces of a conveyor belt and plastic sheeting in the unventilated portion of the Enhanced Characterization of the Repository Block (ECRB) Cross Drift in 2003 and 2005 at Yucca Mountain, Nevada. The chemistry of these puddle water samples is very different than that of pore water samples from borehole cores in the same region of the Cross Drift or than seepage water samples collected from the Exploratory Studies Facility tunnel in 2005. The origin of the puddle water is condensation on surfaces of introduced materials and its chemistry is dominated by components of the introduced materials. Large CO2 concentrations may be indicative of localized chemical conditions induced by biologic activity. ?? 2007 Materials Research Society.

  12. Chemistry of Water Collected From an Unventilated Drift, Yucca Mountain, Nevada

    SciTech Connect

    Marshall, Brian D.; Peterman, Zell E.

    2007-07-01

    Water samples (referred to as puddle water samples) were collected from the surfaces of a conveyor belt and plastic sheeting in the unventilated portion of the Enhanced Characterization of the Repository Block (ECRB) Cross Drift in 2003 and 2005 at Yucca Mountain, Nevada. The chemistry of these puddle water samples is very different than that of pore water samples from borehole cores in the same region of the Cross Drift or than seepage water samples collected from the Exploratory Studies Facility tunnel in 2005. The origin of the puddle water is condensation on surfaces of introduced materials and its chemistry is dominated by components of the introduced materials. Large CO{sub 2} concentrations may be indicative of localized chemical conditions induced by biologic activity. (authors)

  13. Spatial and temporal patterns in water chemistry of two high elevation lakes in southeast Wyoming

    SciTech Connect

    Musselman, R.C.

    1995-12-31

    The Glacier Lakes Ecosystem Experiments Site (GLEES) was established to examine the effects of atmospheric deposition and climate change on alpine and subalpine ecosystems. This report documents temporal and spatial trends during 1993 in water chemistry in East and West Glacier Lakes. Data are presented on seasonal and lake depth changes in water chemistry of the two lakes. The application of the results to appropriate sampling protocols for two alpine lakes is discussed. Both lakes were sampled during the same day, at midday. Samples were kept cool, returned to the lab the same day, and filtered for analysis. Samples were analyzed for cations and anions, pH, and conductivity at the Rocky Mountain Station Water Chemistry laboratory. Silica and aluminum were also measured for some sample dates.

  14. Application of the Reactor Analysis Support Package LWR set-point analysis guidelines

    SciTech Connect

    Engel, R.E.; Sorensen, J.M.; May, R.S.; Doran, K.J.; Trikouros, N.G.; Mozzias, E.S.

    1989-07-01

    Frequently, a situation is encountered in which the technical specification setpoints established by the plant safety analysis are judged to be unacceptable from a plant operational standpoint. This report documents the application of the Electric Power Research Institute (EPRI) Reactor Analysis Support Package (RASP) Light Water Reactor (LWR) setpoint analysis guidelines to provide justification for relaxing the high pressure setpoints at the Oyster Creek Nuclear Generation Station. More Specifically, the plant operation's staff determined that it was desirable to provide increased margin for measurement uncertainties in the high pressure instrument and safety valve setpoints. Previous experience had indicated that there was insufficient margin to justify the desired setpoints using conventional deterministic inputs to the safety analysis and plant performance evaluation process. Therefore, it was determined that the RASP LWR setpoint analysis guidelines, which incorporated the use of a statistical combination of uncertainties methodology, would be used to establish an acceptable set of high pressure setpoints. This report documents the results of applying the RASP setpoint analysis guidelines to provide justification for an acceptable set of high pressure setpoints for the Oyster Creek station. 14 refs., 53 figs., 28 tabs.

  15. Modeling and Analysis of UN TRISO Fuel for LWR Application Using the PARFUME Code

    SciTech Connect

    Blaise Collin

    2014-08-01

    The Idaho National Laboraroty (INL) PARFUME (particle fuel model) code was used to assess the overall fuel performance of uranium nitride (UN) tristructural isotropic (TRISO) ceramic fuel under irradiation conditions typical of a Light Water Reactor (LWR). The dimensional changes of the fuel particle layers and kernel were calculated, including the formation of an internal gap. The survivability of the UN TRISO particle was estimated depending on the strain behavior of the constituent materials at high fast fluence and burn up. For nominal cases, internal gas pressure and representative thermal profiles across the kernel and layers were determined along with stress levels in the inner and outer pyrolytic carbon (IPyC/OPyC) and silicon carbide (SiC) layers. These parameters were then used to evaluate fuel particle failure probabilities. Results of the study show that the survivability of UN TRISO fuel under LWR irradiation conditions might only be guaranteed if the kernel and PyC swelling rates are limited at high fast fluence and burn up. These material properties have large uncertainties at the irradiation levels expected to be reached by UN TRISO fuel in LWRs. Therefore, a large experimental effort would be needed to establish material properties, including kernel and PyC swelling rates, under these conditions before definitive conclusions can be drawn on the behavior of UN TRISO fuel in LWRs.

  16. Effects of LWR coolant environments on fatigue design curves of carbon and low-alloy steels

    SciTech Connect

    Chopra, O.K.; Shack, W.J.

    1998-03-01

    The ASME Boiler and Pressure Vessel Code provides rules for the construction of nuclear power plant components. Figures I-9.1 through I-9.6 of Appendix I to Section III of the code specify fatigue design curves for structural materials. While effects of reactor coolant environments are not explicitly addressed by the design curves, test data indicate that the Code fatigue curves may not always be adequate in coolant environments. This report summarizes work performed by Argonne National Laboratory on fatigue of carbon and low-alloy steels in light water reactor (LWR) environments. The existing fatigue S-N data have been evaluated to establish the effects of various material and loading variables such as steel type, dissolved oxygen level, strain range, strain rate, temperature, orientation, and sulfur content on the fatigue life of these steels. Statistical models have been developed for estimating the fatigue S-N curves as a function of material, loading, and environmental variables. The results have been used to estimate the probability of fatigue cracking of reactor components. The different methods for incorporating the effects of LWR coolant environments on the ASME Code fatigue design curves are presented.

  17. Ground-water, surface-water, and water-chemistry data, Black Mesa area, northeastern Arizona--2004-05

    USGS Publications Warehouse

    Truini, Margot; Macy, J.P.

    2006-01-01

    The N aquifer is the major source of water in the 5,400-square-mile area of Black Mesa in northeastern Arizona. Availability of water is an important issue in this area because of continued industrial and municipal use, a growing population, and precipitation of about 6 to 14 inches per year. The monitoring program in the Black Mesa area has been operating since 1971 and is designed to determine the long-term effects of ground-water withdrawals from the N aquifer for industrial and municipal uses. The monitoring program includes measurements of (1) ground-water pumping, (2) ground-water levels, (3) spring discharge, (4) surface-water discharge, (5) ground-water chemistry, and (6) periodic testing of ground-water withdrawal meters. In 2004, total ground-water withdrawals were 7,210 acre-feet, industrial withdrawals were 4,370 acre-feet, and municipal withdrawals were 2,840 acre-feet. From 2003 to 2004, total withdrawals decreased by less than 1 percent, industrial withdrawals decreased by 2 percent, and municipal withdrawals increased by 2 percent. From 2004 to 2005, annually measured water levels declined in 6 of 13 wells in the unconfined areas of the aquifer, and the median change was -0.1 foot. Water levels declined in 8 of 12 wells in the confined area of the aquifer, and the median change was -1.2 feet. From the prestress period (prior to 1965) to 2005, the median water-level change for 33 wells was -9.0 feet. Median water-level changes were -0.6 foot for 16 wells in the unconfined areas and -32.0 feet for 17 wells in the confined area. Discharges were measured once in 2004 and once in 2005 at four springs. Discharge increased by 8 percent at Pasture Canyon Spring, decreased by 5 percent at Moenkopi School Spring, increased by 71 percent at an unnamed spring near Dennehotso, and stayed the same at Burro Spring. For the period of record at each spring, discharges from the four springs have fluctuated; however, an increasing or decreasing trend is not apparent

  18. Ground-water, surface-water, and water-chemistry data, Black Mesa area, northeastern Arizona--2003-04

    USGS Publications Warehouse

    Truini, Margot; Macy, Jamie P.; Porter, Thomas J.

    2005-01-01

    The N aquifer is the major source of water in the 5,400-square-mile area of Black Mesa in northeastern Arizona. Availability of water is an important issue in this area because of continued industrial and municipal use, a growing population, and precipitation of about 6 to 14 inches per year. The monitoring program in the Black Mesa area has been operating since 1971 and is designed to determine the long-term effects of ground-water withdrawals from the N aquifer for industrial and municipal uses. The monitoring program includes measurements of (1) ground-water pumping, (2) ground-water levels, (3) spring discharge, (4) surface-water discharge, (5) ground-water chemistry, and (6) periodic testing of ground-water withdrawal meters. In 2003, total ground-water withdrawals were 7,240 acre-feet, industrial withdrawals were 4,450 acre-feet, and municipal withdrawals were 2,790 acre-feet. From 2002 to 2003, total withdrawals decreased by 10 percent, industrial withdrawals decreased by 4 percent, and municipal withdrawals decreased by 20 percent. Flowmeter testing was completed for 24 municipal wells in 2004. The median difference between pumping rates for the permanent meter and a test meter for all the sites tested was -2.9 percent. Values ranged from -10.9 percent at Forest Lake NTUA 1 to +7.8 percent at Rough Rock NTUA 2. From 2003 to 2004, water levels declined in 6 of 12 wells in the unconfined part of the aquifer, and the median change was -0.1 foot. Water levels declined in 7 of 11 wells in the confined part of the aquifer, and the median change was -2.7 feet. From the prestress period (prior to 1965) to 2003, the median water-level change for 26 wells was -23.2 feet. Median water-level change were -6.1 feet for 14 wells in the unconfined parts of the aquifer and and -72.1 feet for 12 wells in the confined part. Discharges were measured once in 2003 and once in 2004 at four springs. Discharge stayed the same at Pasture Canyon Spring, increased 9 percent at

  19. Ground-water, surface-water, and water-chemistry data, Black Mesa area, northeastern Arizona, 2002-03

    USGS Publications Warehouse

    Truini, Margot; Thomas, Blakemore E.

    2004-01-01

    The N aquifer is the major source of water in the 5,400-square-mile area of Black Mesa in northeastern Arizona. Availability of water is an important issue in this area because of continued industrial and municipal use, a growing population, and precipitation of about 6 to 14 inches per year. The monitoring program in the Black Mesa area has been operating since 1971 and is designed to determine the long-term effects of ground-water withdrawals from the N aquifer for industrial and municipal uses. The monitoring program includes measurements of (1) ground-water pumping, (2) ground-water levels, (3) spring discharge, (4) surface-water discharge, (5) ground-water chemistry, and (6) periodic testing of ground-water withdrawal meters. In 2002, total ground-water withdrawals were 8,000 acre-feet, industrial use was 4,640 acre-feet, and municipal use was 3,360 acre-feet. From 2001 to 2002, total withdrawals increased by 4 percent, industrial use increased by 2 percent, and municipal use increased by 7 percent. Flowmeter testing was completed for 32 municipal wells in 2003. The median difference between pumping rates for the permanent meter and a test meter for all the sites tested was -2.0 percent. Values ranged from -13.7 percent at Hopi High School no. 2 to +12.9 percent at Shonto PM3. From 2002 to 2003, water levels declined in 5 of 13 wells in the unconfined part of the aquifer, and the median change was 0.0 foot. Water levels declined in 8 of 13 wells in the confined part of the aquifer, and the median change was -1.1 feet. From the prestress period (prior to 1965) to 2003, the median water-level change for 26 wells was -8.3 feet. Median water-level changes were -0.4 foot for 13 wells in the unconfirned part of the aquifer and -60.3 feet for 13 wells in the confined part. Discharges were measured once in 2002 and once in 2003 at four springs. Discharge decreased by 16 percent at Pasture Canyon Spring, increased 10 percent at Moenkopi Spring and 90 percent at an

  20. Impacts of Lithological and Anthropogenic Factors Affecting Water Chemistry in the Upper Paraguay River Basin.

    PubMed

    Rezende-Filho, Ary T; Valles, Vincent; Furian, Sônia; Oliveira, Célia M S C; Ouardi, Jamila; Barbiero, Laurent

    2015-11-01

    Located in the Upper Paraguay River Basin (UPRB), the Pantanal is considered the world's largest wetland, being rather pristine although increasingly threatened by development programs. The main objective of this paper is to provide a baseline of water chemistry for this region, which is largely unknown as a result of poor accessibility. We used two datasets (70 and 122 water samples) collected in the Pantanal floodplain and surrounding uplands during the wet season occurring from November to March. From the major-ion mineral chemistry, dissolved silica, pH, electrical conductivity (EC), and the ionic forms of N, principal components analysis (PCA) treatments were used to identify and rank the main factors of variability and decipher the associated processes affecting the water chemistry. The results revealed that the water mineral concentration was a major factor of variability and it must be attributed first to lithology and second to agricultural inputs from extensive crop cultivation areas that mainly affects sulfate (SO) concentration on the eastern edge of the Pantanal. These processes influence the floodplain, where (i) the mixing of waters remains the main process, (ii) the weight of the biological and redox processes increased, and (iii) the chemical signature of the extensive cropping is transferred along the São Lourenço Basin down to its confluence with the Cuiaba River. Optimized parameters based on projections in the main factorial score plots were used for the mapping of lithological and agricultural impacts on water chemistry.

  1. Gaseous swelling of U 3 Si 2 during steady-state LWR operation: A rate theory investigation

    DOE PAGES

    Miao, Yinbin; Gamble, Kyle A.; Andersson, David; ...

    2017-07-25

    Rate theory simulations of fission gas behavior in U3Si2 are reported for light water reactor (LWR) steady-state operation scenarios. We developed a model of U3Si2 and implemented into the GRASS-SST code based on available research reactor post-irradiation examination (PIE) data, and density functional theory (DFT) calculations of key material properties. Simplified peripheral models were also introduced to capture the fuel-cladding interaction. The simulations identified three regimes of U3Si2 swelling behavior between 390 K and 1190 K. Under typical steady-state LWR operating conditions where U3Si2 temperature is expected to be below 1000 K, intragranular bubbles are dominant and fission gas ismore » retained in those bubbles. The consequent gaseous swelling is low and associated degradation in the fuel thermal conductivity is also limited. Those predictions of U3Si2 performance during steady-state operations in LWRs suggest that this fuel material is an appropriate LWR candidate fuel material. Fission gas behavior models established based on this work are being coupled to the thermo-mechanical simulation of the fuel behavior using the BISON fuel performance multi-dimensional finite element code.« less

  2. Gaseous Swelling of U3Si2 during Steady-State LWR Operation: A Rate Theory Invesitgation

    DOE PAGES

    Miao, Yinbin; Gamble, Kyle A.; Andersson, David; ...

    2017-10-01

    Rate theory simulations of fission gas behavior in U3Si2 are reported for light water reactor (LWR) steady-state operation scenarios. A model of U3Si2 was developed and implemented into the GRASS-SST code based on available research reactor post-irradiation examination (PIE) data, and density functional theory (DFT) calculations of key material properties. Simplified peripheral models were also introduced to capture the fuel-cladding interaction. The simulations identified three regimes of U3Siz swelling behavior between 390 K and 1190 K. Under typical steady-state LWR operating conditions where U3Si2 temperature is expected to be below 1000 K, intragranular bubbles are dominant and fission gas ismore » retained in those bubbles . The consequent gaseous swelling is low and associated degradation in the fuel thermal conductivity is also limited. Those predictions of U3Si2 performance during steady-state operations in LWRs suggest that this fuel material is an appropriate LWR candidate fuel material. Fission gas behavior models established based on this work are being coupled to the thermo-mechanical simulation of the fuel behavior using the BISON fuel performance multi-dimensional finite element code.« less

  3. Use of Chloroisocyanuarates for Disinfection of Water: Application of Miscellaneous General Chemistry Topics

    NASA Astrophysics Data System (ADS)

    Pinto, Gabriel; Rohrig, Brian

    2003-01-01

    This paper presents a set of motivating exercises to study various general chemistry topics such as formulation, molar mass, stoichiometry, chemical equations, balanced equations, oxidation states, acid base reactions, tautomerism, calculation of formal charges, resonance, chlorinating agents, and the use of chlorine for disinfecting water. These topics can be studied in part through the information found on the labels of chloroisocyanurates, such as sodium dichloroisocyanurate (anhydrous and dihydrate) and trichloroisocyanuric acid, which are used for disinfecting water. Both compounds are readily available as consumer products. The holistic approach presented in this article allows students to focus on the versatility of the general chemistry concepts.

  4. Thermal conductivity of heterogeneous LWR MOX fuels

    NASA Astrophysics Data System (ADS)

    Staicu, D.; Barker, M.

    2013-11-01

    It is generally observed that the thermal conductivity of LWR MOX fuel is lower than that of pure UO2. For MOX, the degradation is usually only interpreted as an effect of the substitution of U atoms by Pu. This hypothesis is however in contradiction with the observations of Duriez and Philiponneau showing that the thermal conductivity of MOX is independent of the Pu content in the ranges 3-15 and 15-30 wt.% PuO2 respectively. Attributing this degradation to Pu only implies that stoichiometric heterogeneous MOX can be obtained, while we show that any heterogeneity in the plutonium distribution in the sample introduces a variation in the local stoichiometry which in turn has a strong impact on the thermal conductivity. A model quantifying this effect is obtained and a new set of experimental results for homogeneous and heterogeneous MOX fuels is presented and used to validate the proposed model. In irradiated fuels, this effect is predicted to disappear early during irradiation. The 3, 6 and 10 wt.% Pu samples have a similar thermal conductivity. Comparison of the results for this homogeneous microstructure with MIMAS (heterogeneous) fuel of the same composition showed no difference for the Pu contents of 3, 5.9, 6, 7.87 and 10 wt.%. A small increase of the thermal conductivity was obtained for 15 wt.% Pu. This increase is of about 6% when compared to the average of the values obtained for 3, 6 and 10 wt.% Pu. For comparison purposes, Duriez also measured the thermal conductivity of FBR MOX with 21.4 wt.% Pu with O/M = 1.982 and a density close to 95% TD and found a value in good agreement with the estimation obtained using the formula of Philipponneau [8] for FBR MOX, and significantly lower than his results corresponding to the range 3-15 wt.% Pu. This difference in thermal conductivity is of about 20%, i.e. higher than the measurement uncertainties.Thus, a significant difference was observed between FBR and PWR MOX fuels, but was not explained. This difference

  5. Ground-water, surface-water and water-chemistry data, Black Mesa area, northeastern Arizona: 2001-02

    USGS Publications Warehouse

    Thomas, Blakemore E.

    2002-01-01

    The N aquifer is the major source of water in the 5,400-square-mile area of Black Mesa in northeastern Arizona. Availability of water is an important issue in this area because of continued industrial and municipal use, a growing population, and precipitation of about 6 to 14 inches per year. The monitoring program in the Black Mesa area has been operating since 1971 and is designed to determine the long-term effects of ground-water withdrawals from the N aquifer for industrial and municipal uses. The monitoring program includes measurements of (1) ground-water pumping, (2) ground-water levels, (3) spring discharge, (4) surface-water discharge, and (5) ground-water chemistry. In 2001, total ground-water withdrawals were 7,680 acre-feet, industrial use was 4,530 acre-feet, and municipal use was 3,150 acre-feet. From 2000 to 2001, total withdrawals decreased by 1 percent, industrial use increased by 1 percent, and municipal use decreased by 3 percent. From 2001 to 2002, water levels declined in 5 of 14 wells in the unconfined part of the aquifer, and the median change was +0.2 foot. Water levels declined in 12 of 17 wells in the confined part of the aquifer, and the median change was -1.4 feet. From the prestress period (prior to 1965) to 2002, the median water-level change for 32 wells was -15.8 feet. Median water-level changes were -1.3 feet for 15 wells in the unconfined part of the aquifer and -31.7 feet for 17 wells in the confined part. Discharges were measured once in 2001 and once in 2002 at four springs. Discharges decreased by 26 percent and 66 percent at two springs, increased by 100 percent at one spring, and did not change at one spring. For the past 10 years, discharges from the four springs have fluctuated; however, an increasing or decreasing trend is not apparent. Continuous records of surface-water discharge have been collected from 1976 to 2001 at Moenkopi Wash, 1996 to 2001 at Laguna Creek, 1993 to 2001 at Dinnebito Wash, and 1994 to 2001 at

  6. Ground-water, surface-water, and water-chemistry data, Black Mesa area, Northeastern Arizona: 1999

    USGS Publications Warehouse

    Thomas, Blakemore E.; Truini, Margot

    2000-01-01

    The N aquifer is the major source of water in the 5,400-square-mile area of Black Mesa in northeastern Arizona. Availability of water is an important issue in this area because of continued industrial and municipal use, a growing population, and a precipitation of only about 6 to 12 inches per year. The monitoring program in Black Mesa has been operating since 1971 and is designed to determine the long-term effects of ground-water withdrawals from the N aquifer for industrial and municipal uses. The monitoring program includes measurements of (1) ground-water pumping, (2) ground-water levels, (3) spring discharge, (4) surface-water discharge, and (5) ground-water chemistry. In 1999, total ground-water withdrawals were 7,110 acre-feet, industrial use was 4,210 acre-feet, and municipal use was 2,900 acre-feet. From 1998 to 1999, total withdrawals increased by 0.7 percent, industrial use increased by 4 percent, and municipal use decreased by 4 percent. From 1998 to 1999, water levels declined in 11 of 15 wells in the unconfined part of the aquifer, and the median decline was 0.7 foot. Water levels declined in 14 of 16 wells in the confined part of the aquifer, and the median decline was 1.2 feet. From the prestress period (prior to 1965) to 1999, the median water-level decline in 31 wells was 10.6 feet. Median water-level changes were 0.0 foot for 15 wells in the unconfined part of the aquifer and a decline of 45.5 feet in 16 wells in the confined part. From 1998 to 1999, discharges were measured annually at four springs. Discharges declined 30 percent and 3 percent at 2 springs, did not change at 1 spring, and increased by 11 percent at 1 spring. For the past 10 years, discharges from the four springs have fluctuated; however, an increasing or decreasing trend was not observed. Continuous records of surface-water discharge have been collected from July 1976 to 1999 at Moenkopi Wash, July 1996 to 1999 at Laguna Creek, June 1993 to 1999 at Dinnebito Wash, and April

  7. Equipment designs for the spent LWR fuel dry storage demonstration

    SciTech Connect

    Steffen, R.J.; Kurasch, D.H.; Hardin, R.T.; Schmitten, P.F.

    1980-01-01

    In conjunction with the Spent Fuel Handling and Packaging Program (SFHPP) equipment has been designed, fabricated and successfully utilized to demonstrate the packaging and interim dry storage of spent LWR fuel. Surface and near surface storage configurations containing PWR fuel assemblies are currently on test and generating baseline data. Specific areas of hardware design focused upon include storage cell components and the support related equipment associated with encapsulation, leak testing, lag storage, and emplacement operations.

  8. Understanding EUV mask blank surface roughness induced LWR and associated roughness requirement

    SciTech Connect

    Yan, Pei-Yang; Zhang, Guojing; Gullickson, Eric M.; Goldberg, Kenneth A.; Benk, Markus P.

    2015-03-01

    Extreme ultraviolet lithography (EUVL) mask multi-layer (ML) blank surface roughness specification historically comes from blank defect inspection tool requirement. Later, new concerns on ML surface roughness induced wafer pattern line width roughness (LWR) arise. In this paper, we have studied wafer level pattern LWR as a function of EUVL mask surface roughness via High-NA Actinic Reticle Review Tool. We found that the blank surface roughness induced LWR at current blank roughness level is in the order of 0.5nm 3σ for NA=0.42 at the best focus. At defocus of ±40nm, the corresponding LWR will be 0.2nm higher. Further reducing EUVL mask blank surface roughness will increase the blank cost with limited benefit in improving the pattern LWR, provided that the intrinsic resist LWR is in the order of 1nm and above.

  9. Trends in the chemistry of precipitation and surface water in a national network of small watersheds

    USGS Publications Warehouse

    Aulenbach, Brent T.; Hooper, R.P.; Bricker, O.P.

    1996-01-01

    Trends in precipitation and surface water chemistry at a network of 15 small watersheds ( < 10 km2) in the USA were evaluated using a statistical test for monotonic trends (the seasonal Kendall test) and a graphical smoothing technique for the visual identification of trends. Composite precipitation samples were collected weekly and surface water samples were collected at least monthly. Concentrations were adjusted before trend analysis, by volume for precipitation samples and by flow for surface water samples. A relation between precipitation and surface water trends was not evident either for individual inorganic solutes or for solute combinations, such as ionic strength, at most sites. The only exception was chloride, for which there was a similar trend at 60% of the sites. The smoothing technique indicated that short-term patterns in precipitation chemistry were not reflected in surface waters. The magnitude of the short-term variations in surface water concentration was generally larger than the overall long-term trend, possibly because flow adjustment did not adequately correct for climatic variability. Detecting the relation between precipitation and surface water chemistry trends may be improved by using a more powerful sampling strategy and by developing better methods of concentration adjustment to remove the effects of natural variation in surface waters.

  10. IMPACT OF WATER CHEMISTRY ON LOCALIZED CORROSION OF COPPER PITTING

    EPA Science Inventory

    This project will help identify what waters are problematic in causing the corrosion of copper pipes and improve understanding of how water distribution leads to corrosion. This project will also focus on the prevention of pinhole leaks and how to reverse them once they occur. ...

  11. Sampling procedure for lake or stream surface water chemistry

    Treesearch

    Robert Musselman

    2012-01-01

    Surface waters collected in the field for chemical analyses are easily contaminated. This research note presents a step-by-step detailed description of how to avoid sample contamination when field collecting, processing, and transporting surface water samples for laboratory analysis.

  12. Water chemistry and antimicrobial treatment in poultry processing

    USDA-ARS?s Scientific Manuscript database

    This study examined the influence of calcium and magnesium ions in process water on the solubility of trisodium phosphate. Water used in poultry processing operations may be treated with sanitizers such as trisodium phosphate to reduce microbial activity and the risk of contamination. This occurs wh...

  13. Aggregation of asbestos fibers in water: role of solution chemistry

    NASA Astrophysics Data System (ADS)

    Wu, L.; Ortiz, C. P.; Jerolmack, D. J.

    2016-12-01

    Aggregation kinetics and stability of colloidal particles have been extensively studied using bulk techniques such as dynamic light scattering; these techniques involve large ensembles of particles and interpretation of results is difficult when particles are non-spherical and poorly characterized, as is always the case with non-ideal natural hazardous materials such as asbestos fibers. These difficulties hinder greatly progress on fundamental understanding of whether the classic colloidal aggregation theories can be applied to natural materials and how the heterogeneity of particles (e.g., shape) affects the colloidal aggregation kinetics and structure. By using in-situ microscopy and particle tracking techniques, we were able to observe the particle-by-particle growth of aggregated formed by elongated particles (synthetic glass rods and natural asbestos fibers) and demonstrated the rod-shaped geometry induced novel structures and growth dynamics that challenge existing theory. In this study, we continue to use asbestos as model system of elongated colloidal contaminant, and investigate the effects of changing solution chemistry (e.g., ionic strength, pH, and natural organic matter (NOM)), on growth dynamics and aggregates structure. The results show that aggregate growth curves are self-similar with a characteristic timescale that increases with increasing pH. By varying ionic strength for fixed pH values, we determine that the ccc is sensitive to pH. Fractal dimension decreases slightly with increasing pH and decreasing ionic strength, indicating that stronger inter-particle repulsion create sparser aggregates; however, the magnitude of the solution chemistry effects is much smaller than that of colloid shape. In monovalent solutions, regardless of their concentration, HA drastically reduces the aggregation kinetics of asbestos fiber. This work may lead to enhanced prediction of the colloidal contaminants' mobility in the environment, bioavailability, and

  14. Ground- and Surface-Water Chemistry of Handcart Gulch, Park County, Colorado, 2003-2006

    USGS Publications Warehouse

    Verplanck, Philip L.; Manning, Andrew H.; Kimball, Briant A.; McCleskey, R. Blaine; Runkel, Robert L.; Caine, Jonathan Saul; Adams, Monique; Gemery-Hill, Pamela A.; Fey, David L.

    2008-01-01

    As part of a multidisciplinary project to determine the processes that control ground-water chemistry and flow in mineralized alpine environments, ground- and surface-water samples from Handcart Gulch, Colorado were collected for analysis of inorganic solutes and water and dissolved sulfate stable isotopes in selected samples. The primary aim of this study was to document variations in ground-water chemistry in Handcart Gulch and to identify changes in water chemistry along the receiving stream of Handcart Gulch. Water analyses are reported for ground-water samples collected from 12 wells in Handcart Gulch, Colorado. Samples were collected between August 2003 and October 2005. Water analyses for surface-water samples are reported for 50 samples collected from Handcart Gulch and its inflows during a low-flow tracer injection on August 6, 2003. In addition, water analyses are reported for three other Handcart Gulch stream samples collected in September 2005 and March 2006. Reported analyses include field parameters (pH, specific conductance, temperature, dissolved oxygen, and Eh), major and trace constituents, oxygen and hydrogen isotopic composition of water and oxygen and sulfur isotopic composition of dissolved sulfate. Ground-water samples from this study are Ca-SO4 type and range in pH from 2.5 to 6.8. Most of the samples (75 percent) have pH values between 3.3 and 4.3. Surface water samples are also Ca-SO4 type and have a narrower range in pH (2.7?4.0). Ground- and surface-water samples vary from relatively dilute (specific conductance of 68 ?S/cm) to concentrated (specific conductance of 2,000 ?S/cm).

  15. SPENT NUCLEAR FUEL STORAGE BASIN WATER CHEMISTRY: ELECTROCHEMICAL EVALUATION OF ALUMINUM CORROSION

    SciTech Connect

    Hathcock, D

    2007-10-30

    The factors affecting the optimal water chemistry of the Savannah River Site spent fuel storage basin must be determines in order to optimize facility efficiency, minimize fuel corrosion, and reduce overall environmental impact from long term spent nuclear fuel storage at the Savannah River Site. The Savannah River National Laboratory is using statistically designed experiments to study the effects of NO{sub 3}{sup -}, SO{sub 4}{sup 2-}, and Cl{sup -} concentrations on alloys commonly used not only as fuel cladding, but also as rack construction materials The results of cyclic polarization pitting and corrosion experiments on samples of Al 6061 and 1100 alloys will be used to construct a predictive model of the basin corrosion and its dependence on the species in the basin. The basin chemistry model and corrosion will be discussed in terms of optimized water chemistry envelope and minimization of cladding corrosion.

  16. Results of ground-water, surface-water, and water-chemistry monitoring, Black Mesa area, northeastern Arizona, 1994

    USGS Publications Warehouse

    Littin, G.R.; Monroe, S.A.

    1995-01-01

    The Black Mesa monitoring program is designed to document long-term effects of ground-water pumping from the N aquifer by industrial and municipal users. The N aquifer is the major source of water in the 5,400-square-mile Black Mesa area, and the ground water occurs under confined and unconfined conditions. Monitoring activities include continuous and periodic measurements of (1) ground-water pumpage from the confined and unconfined areas of the aquifer, (2) ground-water levels in the confined and unconfined areas of the aquifer, (3) surface-water discharge, and (4) chemistry of the ground water and surface water. In 1994, ground-water withdrawals for industrial and municipal use totaled about 7,000 acre-feet, which is an 8-percent increase from the previous year. Pumpage from the confined part of the aquifer increased by about 9 percent to 5,400 acre-feet, and pumpage from the unconfined part of the aquifer increased by about 2 percent to 1,600 acre-feet. Water-level declines in the confined area during 1994 were recorded in 10 of 16 wells, and the median change was a decline of about 2.3 feet as opposed to a decline of 3.3 feet for the previous year. The median change in water levels in the unconfined area was a rise of 0.1 foot in 1994 as opposed to a decline of 0.5 foot in 1993. Measured low-flow discharge along Moenkopi Wash decreased from 3.0 cubic feet per second in 1993 to 2.9 cubic feet per second in 1994. Eleven low-flow measurements were made along Laguna Creek between Tsegi, Arizona, and Chinle Wash to determine the amount of discharge that would occur as seepage from the N aquifer under optimal base-flow conditions. Discharge was 5.6 cubic feet per second near Tsegi and 1.5 cubic feet per second above the confluence with Chinle Wash. Maximum discharge was 5.9 cubic feet per second about 4 miles upstream from Dennehotso. Discharge was measured at three springs. The changes in discharge at Burro and Whisky Springs were small and within the uncertainty of

  17. Analytical chemistry in water quality monitoring during manned space missions

    NASA Astrophysics Data System (ADS)

    Artemyeva, Anastasia A.

    2016-09-01

    Water quality monitoring during human spaceflights is essential. However, most of the traditional methods require sample collection with a subsequent ground analysis because of the limitations in volume, power, safety and gravity. The space missions are becoming longer-lasting; hence methods suitable for in-flight monitoring are demanded. Since 2009, water quality has been monitored in-flight with colorimetric methods allowing for detection of iodine and ionic silver. Organic compounds in water have been monitored with a second generation total organic carbon analyzer, which provides information on the amount of carbon in water at both the U.S. and Russian segments of the International Space Station since 2008. The disadvantage of this approach is the lack of compound-specific information. The recently developed methods and tools may potentially allow one to obtain in-flight a more detailed information on water quality. Namely, the microanalyzers based on potentiometric measurements were designed for online detection of chloride, potassium, nitrate ions and ammonia. The recent application of the current highly developed air quality monitoring system for water analysis was a logical step because most of the target analytes are the same in air and water. An electro-thermal vaporizer was designed, manufactured and coupled with the air quality control system. This development allowed for liberating the analytes from the aqueous matrix and further compound-specific analysis in the gas phase.

  18. Sterilization Resistance of Bacterial Spores Explained with Water Chemistry.

    PubMed

    Friedline, Anthony W; Zachariah, Malcolm M; Middaugh, Amy N; Garimella, Ravindranath; Vaishampayan, Parag A; Rice, Charles V

    2015-11-05

    Bacterial spores can survive for long periods without nutrients and in harsh environmental conditions. This survival is influenced by the structure of the spore, the presence of protective compounds, and water retention. These compounds, and the physical state of water in particular, allow some species of bacterial spores to survive sterilization schemes with hydrogen peroxide and UV light. The chemical nature of the spore core and its water has been a subject of some contention and the chemical environment of the water impacts resistance paradigms. Either the spore has a glassy core, where water is immobilized along with other core components, or the core is gel-like with mobile water diffusion. These properties affect the movement of peroxide and radical species, and hence resistance. Deuterium solid-state NMR experiments are useful for examining the nature of the water inside the spore. Previous work in our lab with spores of Bacillus subtilis indicate that, for spores, the core water is in a more immobilized state than expected for the gel-like core theory, suggesting a glassy core environment. Here, we report deuterium solid-state NMR observations of the water within UV- and peroxide-resistant spores from Bacillus pumilus SAFR-032. Variable-temperature NMR experiments indicate no change in the line shape after heating to 50 °C, but an overall decrease in signal after heating to 100 °C. These results show glass-like core dynamics within B. pumilus SAFR-032 that may be the potential source of its known UV-resistance properties. The observed NMR traits can be attributed to the presence of an exosporium containing additional labile deuterons that can aid in the deactivation of sterilizing agents.

  19. Cloud water chemistry and the production of sulfates in clouds

    NASA Technical Reports Server (NTRS)

    Hegg, D. A.; Hobbs, P. V.

    1981-01-01

    Measurements are presented of the pH and ionic content of water collected in clouds over western Washington and the Los Angeles Basin. Evidence for sulfate production in some of the clouds is presented. Not all of the sulfur in the cloud water was in the form of sulfate. However, the measurements indicate that the production of sulfate in clouds is of considerable significance in the atmosphere. Comparison of field measurements with model results show reasonable agreement and suggest that the production of sulfate in cloud water is a consequence of more than one conversion mechanism.

  20. Cloud water chemistry and the production of sulfates in clouds

    NASA Technical Reports Server (NTRS)

    Hegg, D. A.; Hobbs, P. V.

    1981-01-01

    Measurements are presented of the pH and ionic content of water collected in clouds over western Washington and the Los Angeles Basin. Evidence for sulfate production in some of the clouds is presented. Not all of the sulfur in the cloud water was in the form of sulfate. However, the measurements indicate that the production of sulfate in clouds is of considerable significance in the atmosphere. Comparison of field measurements with model results show reasonable agreement and suggest that the production of sulfate in cloud water is a consequence of more than one conversion mechanism.

  1. Measurements and sensitivities of LWR in poly spacers

    NASA Astrophysics Data System (ADS)

    Ayal, Guy; Shauly, Eitan; Levi, Shimon; Siany, Amit; Adan, Ofer; Shacham-Diamand, Yosi

    2010-03-01

    LER and LWR have long been considered a primary issue in process development and monitoring. Development of a low power process flavors emphasizes the effect of LER, LWR on different aspects of the device. Gate level performance, particularly leakage current at the front end of line, resistance and reliability in the back-end layers. Traditionally as can be seen in many publications, for the front end of line the focus is mainly on Poly and Active area layers. Poly spacers contribution to the gate leakage, for example, is rarely discussed. Following our research done on sources of gate leakage, we found leakage current (Ioff) in some processes to be highly sensitive to changes in the width of the Poly spacers - even more strongly to the actual Poly gate CDs. Therefore we decided to measure Poly spacers LWR, its correlation to the LWR in the poly, and its sensitivity to changes in layout and OPC. In our last year publication, we defined the terms LLER (Local Line Edge Roughness) and LLWR (Local Line Width Roughness). The local roughness is measured as the 3-sigma value of the line edge/width in a 5-nm segment around the measurement point. We will use these terms in this paper to evaluate the Poly roughness impact on Poly spacer's roughness. A dedicated test chip was designed for the experiments, having various transistors layout configurations with different densities to cover the all range of process design rules. Applied Materials LER and LWR innovative algorithms were used to measure and characterize the spacer roughness relative to the distance from the active edges and from other spaces. To accurately measure all structures in a reasonable time, the recipes were automatically generated from CAD. On silicon, after poly spacers generation, the transistors no longer resemble the Poly layer CAD layout, their morphology is different compared with Photo/Etch traditional structures , and dimensions vary significantly. In this paper we present metrology and

  2. Spatial And Temporal Variation In The Dissolved Trace Element Chemistry Of Chesapeake Bay Surface Waters

    NASA Astrophysics Data System (ADS)

    Dorval, E.; Hannigan, R.; Jones, C.

    2001-12-01

    Surface waters were collected from sea grass beds around the Chesapeake Bay of Virginia as well as from the mouths of the York, James, Potomac and Rappahannock rivers and Tangier and Smith islands. These sea grass beds represent the nursery habitats for a variety of sport fish including Spotted Sea Trout and Weakfish. Trace element ratios of fish otoliths record the unique chemistries of bodies of water in which the fish live. The data presented here represent the initial results of a "ground-truthing" investigation of the relationships between the water and otolith chemistry. Waters were collected bi-monthly (July through September) from 30 sites around the western and eastern shore of Chesapeake Bay including major tributaries and Tangier and Smith islands. Water was collected using trace metal clean procedures including filtration through a 0.45 uM filter and acidification in the field to pH < 2 with ultra-pure nitric acid. Dissolved trace element composition was measured by sector field ICP-MS. The trace element chemistry of samples show both spatial and temporal variation. Using discriminant analysis it is not possible to statistically classify samples to the respective zones (western shore, eastern shore or islands) but it is possible to separate samples from the Tangier and Smith island sites from the eastern and western shore sites. Elements that allow this classification include Ce and Th, which are found in higher concentration in the samples from the island sites than in the eastern and western shore samples. These relationships follow the trends observed in pH and dissolved oxygen likely related to a restricted flow regime between the islands and the eastern shore. Mg/Ca and Sr/Ca ratios are unique for the sea grass beds along the western shore and allow the distinction of beds located between the York and Rappahannock rivers from those between the Rappahannock and Potomac rivers. Sr and Ba concentrations are variable between sites along the eastern

  3. Materials chemistry: Organic polymers form fuel from water

    NASA Astrophysics Data System (ADS)

    Vyas, Vijay S.; Lotsch, Bettina V.

    2015-05-01

    Porous polymers have joined the ranks of light-activated catalysts that split water into hydrogen, a carbon-free alternative to fossil fuels. Their properties are easily tuned -- a big plus for the development of practically useful catalysts.

  4. Water chemistry-based classification of streams and implications for restoring mined Appalachian watersheds

    SciTech Connect

    Merovich, G.T.; Stiles, J.M.; Petty, J.T.; Ziemkiewicz, P.F.; Fulton, J.B.

    2007-07-15

    We analyzed seasonal water samples from the Cheat and Tygart Valley river basins, West Virginia, USA, in an attempt to classify streams based on water chemistry in this coal-mining region. We also examined temporal variability among water samples. Principal component analysis identified two important dimensions of variation in water chemistry. This variation was determined largely by mining-related factors (elevated metals, sulfates, and conductivity) and an alkalinity-hardness gradient. Cluster analysis grouped water samples into six types that we described as reference, soft, hard, transitional, moderate acid mine drainage, and severe acid mine drainage. These types were statistically distinguishable in multidimensional space. Classification tree analysis confirmed that chemical constituents related to acid mine drainage and acid rain distinguished these six groups. Hard, soft, and severe acid mine drainage type streams were temporally constant compared to streams identified as reference, transitional, and moderate acid mine drainage type, which had a greater tendency to shift to a different water type between seasons. Our research is the first to establish a statistically supported stream classification system in mined watersheds. The results suggest that human-related stressors superimposed on geology are responsible for producing distinct water quality types in this region as opposed to more continuous variation in chemistry that would be expected in an unimpacted setting. These findings provide a basis for simplifying stream monitoring efforts, developing generalized remediation strategies, and identifying specific remediation priorities in mined Appalachian watersheds.

  5. Water chemistry-based classification of streams and implications for restoring mined Appalachian watersheds.

    PubMed

    Merovich, George T; Stiles, James M; Petty, J Todd; Ziemkiewicz, Paul F; Fulton, Jennifer B

    2007-07-01

    We analyzed seasonal water samples from the Cheat and Tygart Valley river basins, West Virginia, USA, in an attempt to classify streams based on water chemistry in this coal-mining region. We also examined temporal variability among water samples. Principal component analysis identified two important dimensions of variation in water chemistry. This variation was determined largely by mining-related factors (elevated metals, sulfates, and conductivity) and an alkalinity-hardness gradient. Cluster analysis grouped water samples into six types that we described as reference, soft, hard, transitional, moderate acid mine drainage, and severe acid mine drainage. These types were statistically distinguishable in multidimensional space. Classification tree analysis confirmed that chemical constituents related to acid mine drainage and acid rain distinguished these six groups. Hard, soft, and severe acid mine drainage type streams were temporally constant compared to streams identified as reference, transitional, and moderate acid mine drainage type, which had a greater tendency to shift to a different water type between seasons. Our research is the first to establish a statistically supported stream classification system in mined watersheds. The results suggest that human-related stressors superimposed on geology are responsible for producing distinct water quality types in this region as opposed to more continuous variation in chemistry that would be expected in an unimpacted setting. These findings provide a basis for simplifying stream monitoring efforts, developing generalized remediation strategies, and identifying specific remediation priorities in mined Appalachian watersheds.

  6. THE TWO FACES OF WATER CHEMISTRY: STRESSOR ON, AND INDICATOR OF, THE ECOLOGICAL CONDITION OF THE GREAT RIVERS.

    EPA Science Inventory

    This poster presentation is designed to enlighten the interested masses about water quality assessment tools. It is not intended for policy, rather to stimulate thought on the importance of developing water chemistry as as assessment tool.

  7. Chemistry of thermal waters and mineralogy of the new deposits at Mount St. Helens: a preliminary report

    SciTech Connect

    Dethier, D.P.; Frank, D.; Peavear, D.R.

    1980-12-01

    After May 18, 1980 eruption of Mount St. Helens, Washington, interactions between the hot deposits and shallow ground water produced ephemeral phreatic eruptions and thermal ponds and streams. In early June water and sediment samples were collected from about 20 sites in the devastated zone to study the initial alteration of the new deposits, and the effects of the eruption on water chemistry. The levels of certain trace elements in thermal waters, and whether these mineralized waters were reaching the North Fork Toutle River in appreciable quantities were studied. Collection and analysis procedures, the mineralogy of the new deposits, and the chemistry of the thermal waters are discussed. Finally, the chemistry of water from different deposits is compared, alteration reactions suggested by the water chemistry, and the mineralogy of the deposits is discussed.

  8. THE TWO FACES OF WATER CHEMISTRY: STRESSOR ON, AND INDICATOR OF, THE ECOLOGICAL CONDITION OF THE GREAT RIVERS.

    EPA Science Inventory

    This poster presentation is designed to enlighten the interested masses about water quality assessment tools. It is not intended for policy, rather to stimulate thought on the importance of developing water chemistry as as assessment tool.

  9. Role(s) of adsorbed water in the surface chemistry of environmental interfaces.

    PubMed

    Rubasinghege, Gayan; Grassian, Vicki H

    2013-04-18

    The chemistry of environmental interfaces such as oxide and carbonate surfaces under ambient conditions of temperature and relative humidity is of great interest from many perspectives including heterogeneous atmospheric chemistry, heterogeneous catalysis, photocatalysis, sensor technology, corrosion science, and cultural heritage science. As discussed here, adsorbed water plays important roles in the reaction chemistry of oxide and carbonate surfaces with indoor and outdoor pollutant molecules including nitrogen oxides, sulfur dioxide, carbon dioxide, ozone and organic acids. Mechanisms of these reactions are just beginning to be unraveled and found to depend on the details of the reaction mechanism as well as the coverage of water on the surface. As discussed here, adsorbed water can: (i) alter reaction pathways and surface speciation relative to the dry surface; (ii) hydrolyze reactants, intermediates and products; (iii) enhance surface reactivity by providing a medium for ionic dissociation; (iv) inhibit surface reactivity by blocking sites; (v) solvate ions; (vi) enhance ion mobility on surfaces and (vii) alter the stability of surface adsorbed species. In this feature article, drawing on research that has been going on for over a decade on the reaction chemistry of oxide and carbonate surfaces under ambient conditions of temperature and relative humidity, a number of specific examples showing the multi-faceted roles of adsorbed water are presented.

  10. Pesticides in Drinking Water: Project-based Learning within the Introductory Chemistry Curriculum.

    ERIC Educational Resources Information Center

    O'Hara, Patricia B.; Sanborn, Jon A.; Howard, Meredith

    1999-01-01

    Describes a four-week laboratory module for an introductory chemistry course that focuses on the analysis of trace levels of xenoestrogenic pesticides in local drinking water and a comparison of the molecular shapes of these pesticides to the hormone estrogen. (WRM)

  11. The effect of water on discharge product growth and chemistry in Li-O2 batteries.

    PubMed

    Kwabi, David G; Batcho, Thomas P; Feng, Shuting; Giordano, Livia; Thompson, Carl V; Shao-Horn, Yang

    2016-09-28

    Understanding what controls Li-O2 battery discharge product chemistry and morphology is key to enabling its practical deployment as a low-cost, high-specific-energy energy conversion technology. Several studies have recently shown that the addition of substantial quantities (hundreds to thousands ppm) of water and weak acids to dimethoxyethane (DME)-based electrolytes can significantly increase Li-O2 battery discharge capacity, without substantially changing the discharge product chemistry, which remains Li2O2. The exact mechanisms behind these device-level improvements, however, are not yet understood. In this study, we show that the presence of water in a DME-based electrolyte decreases the rate of Li2O2 nucleation on the electrode surface during Li-O2 battery discharge, using potentiostatic electrochemical measurements, and direct, ex situ observations of Li2O2 particles. We also show that adding water to an acetonitrile (MeCN)-based electrolyte results in LiOH upon discharge, as opposed to only Li2O2. Using first principles calculations, we propose that this change in discharge product chemistry is attributable to increased proton availability, as shown by a lower pKa for water in MeCN than in DME. This study combines kinetic and morphological analyses with first principles calculations, and elucidates relationships among electrolyte composition, discharge product chemistry and growth mechanisms for the rational design of efficient metal-air batteries.

  12. Pesticides in Drinking Water: Project-based Learning within the Introductory Chemistry Curriculum.

    ERIC Educational Resources Information Center

    O'Hara, Patricia B.; Sanborn, Jon A.; Howard, Meredith

    1999-01-01

    Describes a four-week laboratory module for an introductory chemistry course that focuses on the analysis of trace levels of xenoestrogenic pesticides in local drinking water and a comparison of the molecular shapes of these pesticides to the hormone estrogen. (WRM)

  13. Incorporating landscape characteristics in a distance metric for interpolating between observations of stream water chemistry

    NASA Astrophysics Data System (ADS)

    Lyon, S. W.; Seibert, J.; Lembo, A. J.; Steenhuis, T. S.; Walter, M. T.

    2008-10-01

    Spatial patterns of water chemistry along stream networks can be quantified using synoptic or "snapshot" sampling. The basic idea is to sample stream water at many points over a relatively short period of time. Even for intense sampling campaigns, the number of sample points is limited and interpolation methods, like kriging, are commonly used to produce continuous maps of water chemistry based on the point observations from the synoptic sampling. Interpolated concentrations are influenced heavily by how distance between points along the stream network is defined. In this study, we investigate different ways to define distance and test these based on data from a snapshot sampling campaign in a 37-km2 watershed in the Catskill Mountains region (New York State). Three distance definitions (or metrics) were compared: Euclidean or straight-line distance, in-stream distance, and in-stream distance adjusted according characteristics of the local contributing area, i.e., an adjusted in-stream distance. Using the adjusted distance metric resulted in a lower cross-validation error of the interpolated concentrations, i.e., a better agreement of kriging results with measurements, than the other distance definitions. The adjusted distance metric can also be used in an exploratory manner to test which landscape characteristics are most influential for the spatial patterns of stream water chemistry and, thus, to target future investigations to gain process-based understanding of in-stream chemistry dynamics.

  14. Incorporating landscape characteristics in a distance metric for interpolating between observations of stream water chemistry

    NASA Astrophysics Data System (ADS)

    Lyon, S. W.; Seibert, J.; Lembo, A. J.; Steenhuis, T. S.; Walter, M. T.

    2008-06-01

    Spatial patterns of water chemistry along stream networks can be quantified using synoptic or "snapshot" sampling. The basic idea is to sample stream water at many points over a relatively short period of time. Even for intense sampling campaigns, the number of sample points is limited and interpolation methods, like kriging, are commonly used to produce continuous maps of water chemistry based on the point observations from the synoptic sampling. Interpolated concentrations are influenced heavily by how distance between points along the stream network is defined. In this study, we investigate different ways to define distance and test these based on data from a snapshot sampling campaign in a 37-km2 watershed in the Catskill Mountains region (New York State). Three distance definitions (or metrics) were compared: Euclidean or straight-line distance, in-stream distance, and in-stream distance adjusted according characteristics of the local contributing area, i.e., an adjusted in-stream distance. Using the adjusted distance metric resulted in a lower cross-validation error of the interpolated concentrations, i.e., a better agreement of kriging results with measurements, than the other distance definitions. The adjusted distance metric can also be used in an exploratory manner to test which landscape characteristics are most influential for the spatial patterns of stream water chemistry and, thus, to target future investigations to gain process-based understanding of in-stream chemistry dynamics.

  15. Effects of watershed experiments on water chemistry at the Marcell Experimental Forest. Chapter 14.

    Treesearch

    Stephen D. Sebestyen; Elon S. Verry

    2011-01-01

    The Marcell Experimental Forest (MEF) was established during the 1960s to study the hydrology and ecology of lowland watersheds where upland mineral soils drain to central peatlands (Boelter and Verry 1977). The effects of seven large-scale manipulations on water chemistry have been studied on the MEF watersheds and the data now span up to four decades. In this chapter...

  16. Soil water and xylem chemistry in declining sugar maple stands in Pennsylvania

    Treesearch

    David R. DeWalle; Bryan R. Swistock; William E. Sharpe

    1999-01-01

    Evidence is accumulating that decline of sugar maple, Acer saccharum Marsh., in northern Pennsylvania may be related to overall site fertility as reflected in the chemistry of soil water and bolewood xylem. In this paper we discuss factors related to varying site fertility, including effects of soil liming, past glacialion, topographic position and...

  17. Coagulation chemistries for silica removal from cooling tower water.

    SciTech Connect

    Nyman, May Devan; Altman, Susan Jeanne; Stewart, Tom

    2010-02-01

    The formation of silica scale is a problem for thermoelectric power generating facilities, and this study investigated the potential for removal of silica by means of chemical coagulation from source water before it is subjected to mineral concentration in cooling towers. In Phase I, a screening of many typical as well as novel coagulants was carried out using concentrated cooling tower water, with and without flocculation aids, at concentrations typical for water purification with limited results. In Phase II, it was decided that treatment of source or make up water was more appropriate, and that higher dosing with coagulants delivered promising results. In fact, the less exotic coagulants proved to be more efficacious for reasons not yet fully determined. Some analysis was made of the molecular nature of the precipitated floc, which may aid in process improvements. In Phase III, more detailed study of process conditions for aluminum chloride coagulation was undertaken. Lime-soda water softening and the precipitation of magnesium hydroxide were shown to be too limited in terms of effectiveness, speed, and energy consumption to be considered further for the present application. In Phase IV, sodium aluminate emerged as an effective coagulant for silica, and the most attractive of those tested to date because of its availability, ease of use, and low requirement for additional chemicals. Some process optimization was performed for coagulant concentration and operational pH. It is concluded that silica coagulation with simple aluminum-based agents is effective, simple, and compatible with other industrial processes.

  18. Aluminum in acidic surface waters: chemistry, transport, and effects.

    PubMed Central

    Driscoll, C T

    1985-01-01

    Ecologically significant concentrations of Al have been reported in surface waters draining "acid-sensitive" watersheds that are receiving elevated inputs of acidic deposition. It has been hypothesized that mineral acids from atmospheric deposition have remobilized Al previously precipitated within the soil during soil development. This Al is then thought to be transported to adjacent surface waters. Dissolved mononuclear Al occurs as aquo Al, as well as OH-, F-, SO4(2-), and organic complexes. Although past investigations have often ignored non-hydroxide complexes of Al, it appears that organic and F complexes are the predominant forms of Al in dilute (low ionic strength) acidic surface waters. The concentration of inorganic forms of Al increases exponentially with decreases in solution pH. This response is similar to the theoretical pH dependent solubility of Al mineral phases. The concentration of organic forms of Al, however, is strongly correlated with variations in organic carbon concentration of surface waters rather than pH. Elevated concentrations of Al in dilute acidic waters are of interest because: Al is an important pH buffer; Al may influence the cycling of important elements like P, organic carbon, and trace metals; and Al is potentially toxic to aquatic organisms. An understanding of the aqueous speciation of Al is essential for an evaluation of these processes. PMID:3935428

  19. Removal of sediment and bacteria from water using green chemistry.

    PubMed

    Buttice, Audrey L; Stroot, Joyce M; Lim, Daniel V; Stroot, Peter G; Alcantar, Norma A

    2010-05-01

    Although nearly all newly derived water purification methods have improved the water quality in developing countries, few have been accepted and maintained for long-term use. Field studies indicate that the most beneficial methods use indigenous resources, as they are both accessible and accepted by communities they help. In an effort to implement a material that will meet community needs, two fractions of mucilage gum were extracted from the Opuntia ficus-indica cactus and tested as flocculation agents against sediment and bacterial contamination. As diatomic ions are known to affect both mucilage and promote cell aggregation, CaCl(2) was studied in conjunction and compared with mucilage as a bacteria removal method. To evaluate performance, ion-rich waters that mimic natural water bodies were prepared. Column tests containing suspensions of the sediment kaolin exhibited particle flocculation and settling rates up to 13.2 cm/min with mucilage versus control settling rates of 0.5 cm/min. Bacillus cereus tests displayed flocculation and improved settling times with mucilage concentrations lower than 5 ppm and removal rates between 97 and 98% were observed for high bacteria concentration tests (>10(8) cells/ml). This natural material not only displays water purification abilities, but it is also affordable, renewable and readily available.

  20. Understanding the interplay between water chemistry and electrochemical properties of copper

    NASA Astrophysics Data System (ADS)

    Cong, Hongbo

    The pitting behavior of UNS C11000 copper was investigated in a synthetic potable water found to cause pitting using both driven electrochemical methods and under natural conditions at OCP. The latter was monitored with coupled multi-electrode arrays (CMEA). Tests were also conducted in several HCO 3-, SO42- and Cl- containing-waters with systematic variations in the concentrations of these species. Empirical equations that forecast pitting (EPit) and repassivation (ERp) potential as a function of selected water chemistry variables were developed. OCP was a strong function of water chemistry, pH and time. Maximum OCPs were found to increase with both pH and Cl2. Empirical equations that forecast the OCP as a function of pH and Cl2 were also developed. Natural pitting was tested in different pH synthetic waters (6-10) at various Cl2 levels (0-5 ppm). The CMEA method successfully detected the formation of persistent anodes (pitting sites) in pH ≥7 synthetic waters compared to formation of switchable anodes at pH 6. A pitting factor was determined as a function of water chemistry. Pit events were statistically analyzed and potential excursions were compared to EPit and E Rp. Natural pitting events occurred on a percentage of electrodes once the OCP rose above ERp and this could be rationalized based on the statistical spread in EPit. Pits stopped growing once the OCP dropped below ERp Pitting severity increased with Cl2 level and pH. The cathodic capacity of adjacent cathodic sites as a function of water chemistry and the nature of the cathodic sites was also factored into this analysis. Lastly, the possible roles of deposited aluminum solids in pit initiation were also examined using several diagnostic methods.

  1. Primary water chemistry improvement for radiation exposure reduction at Japanese PWR Plants

    SciTech Connect

    Nishizawa, Eiichi

    1995-03-01

    Radiation exposure during the refueling outages at Japanese Pressurized Water Reactor (PWR) Plants has been gradually decreased through continuous efforts keeping the radiation dose rates at relatively low level. The improvement of primary water chemistry in respect to reduction of the radiation sources appears as one of the most important contributions to the achieved results and can be classified by the plant operation conditions as follows

  2. Ground-water, surface-water, and water-chemistry data, Black Mesa area, northeastern Arizona: 1998

    USGS Publications Warehouse

    Truini, Margot; Baum, Bradley M.; Littin, Gregory R.; Shingoitewa-Honanie, Gayl

    2000-01-01

    The Black Mesa monitoring program is designed to document long-term effects of ground-water pumping from the N aquifer by industrial and municipal users. The N aquifer is the major source of water in the 5,400-square-mile Black Mesa area, and the ground water occurs under confined and unconfined conditions. Monitoring activities include continuous and periodic measurements of (1) ground-water pumpage from the confined and unconfined parts of the aquifer, (2) ground-water levels in the confined and unconfined parts of the aquifer, (3) surface-water discharge, (4) flowmeter tests, and (5) ground-water and surface-water chemistry. In 1998, ground-water withdrawals for industrial and municipal use totaled about 7,060 acre-feet, which is less than a 1 percent decrease from 1997. Pumpage from the confined part of the aquifer decreased by less than 1 percent to 5,470 acre-feet, and pumpage from the unconfined part of the aquifer increased by less than 1 percent to 1,590 acre-feet. Water-level declines in the confined part of the aquifer were recorded in 10 of 14 wells during 1998, and the median change from 1997 was a decline of 3.0 feet as opposed to a rise of 0.2 feet for the change from 1996 to 1997. Water-level declines in the unconfined part of the aquifer were recorded in 9 of 16 wells, and the median change from 1997 was 0.0 feet, which is the same as the median change from 1996 to 1997. Of the 35 pumpage meters on municipal wells that were tested, the difference between metered and tested discharge ranged from +6.3 to -19.6 percent. The average difference was about -3.4 percent. Five of the meters exceeded the allowable difference (10 percent) and should be repaired or replaced. The low-flow discharge at the Moenkopi streamflow-gaging station ranged from 2.6 to 4.7 cubic feet per second in 1998. Streamflow-discharge measurements also were made at Laguna Creek, Dinnebito Wash, and Polacca Wash during 1998. The low-flow discharge ranged from 0.41 to 5.1 cubic feet

  3. Ground-Water, Surface-Water, and Water-Chemistry Data, Black Mesa Area, Northeastern Arizona - 2006-07

    USGS Publications Warehouse

    Truini, Margot; Macy, J.P.

    2008-01-01

    The N aquifer is the major source of water in the 5,400 square-mile Black Mesa area in northeastern Arizona. Availability of water is an important issue in northeastern Arizona because of continued water requirements for industrial and municipal use and the needs of a growing population. Precipitation in the Black Mesa area is typically about 6 to 14 inches per year. The water-monitoring program in the Black Mesa area began in 1971 and is designed to provide information about the long-term effects of ground-water withdrawals from the N aquifer for industrial and municipal uses. This report presents results of data collected for the monitoring program in the Black Mesa area from January 2006 to September 2007. The monitoring program includes measurements of (1) ground-water withdrawals, (2) ground-water levels, (3) spring discharge, (4) surface-water discharge, and (5) ground-water chemistry. Periodic testing of ground-water withdrawal meters is completed every 4 to 5 years. The Navajo Tribal Utility Authority (NTUA) yearly totals for the ground-water metered withdrawal data were unavailable in 2006 due to an up-grade within the NTUA computer network. Because NTUA data is often combined with Bureau of Indian Affairs data for the total withdrawals in a well system, withdrawals will not be published in this year's annual report. From 2006 to 2007, annually measured water levels in the Black Mesa area declined in 3 of 11 wells measured in the unconfined areas of the N aquifer, and the median change was 0.0 feet. Measurements indicated that water levels declined in 8 of 17 wells measured in the confined area of the aquifer. The median change for the confined area of the aquifer was 0.2 feet. From the prestress period (prior to 1965) to 2007, the median water-level change for 30 wells was -11.1 feet. Median water-level changes were 2.9 feet for 11 wells measured in the unconfined areas and -40.2 feet for 19 wells measured in the confined area. Spring flow was measured

  4. Examination of Terrain and Land use Control on Soil Water Chemistry in Two Suburban Watersheds

    NASA Astrophysics Data System (ADS)

    Sopacua, J.; Endreny, T. A.

    2004-12-01

    Scientific literature has advanced our understanding about controlling factors of water chemistry in forested watersheds, however the linkage between watershed characteristics and soil water chemistry in suburban watersheds is poorly understood. A better understanding of suburban watershed characteristics that control soil water chemistry concentrations will help watershed managers in addressing water pollution issue. Soil water samples were taken biweekly from nineteen sampling clusters throughout the study areas; B28 watershed, a 558860 m2 catchment, and Power Station watershed, a 446450 m2 catchment, in Croton New York City water supply system, from June 2001 to August 2002. Watershed characteristics (land use and topographic) were generated from land use data and 2 meters grided digital elevation model using extensive ARC/GIS functions and analyses. Clusters have a range of development density. Relationships between annual average total phosphorous (TP), total nitrogen (TN) and dissolved organic carbon (DOC) concentration and watershed characteristics were examined and regression models for TP, TN, and DOC concentration were developed. The best predictive model for average TP concentration was based on Number of houses and Road width (R2 adj = 0.47), based predictive model for average TN concentration was based on number of houses and impervious area (R2 adj = 0.78), and best predictive model for average DOC concentration based on road width (R2 adj = 0.46).

  5. NUCLEAR CHEMISTRY OF WATER-COOLED FUSION REACTORS: ISSUES AND SOLUTIONS

    SciTech Connect

    Petrov, Andrei Y; Flanagan, George F

    2010-01-01

    ITER is an experimental Tokamak fusion energy reactor that is being built in Cadarache, France, in collaboration with seven agencies representing China, the European Union, India, Japan, Republic of Korea, the Russian Federation, and the United States. The main objective of ITER is to demonstrate the scientific and technical feasibility of a controlled fusion reaction An important U.S. contribution is the design, fabrication, and delivery of the Tokamak Cooling Water System (TCWS). This paper describes the main sources of radioactivity in TCWS water, which are the nitrogen isotopes 16N and 17N, tritium, activated corrosion products, and the carbon isotope 14C; the relative contribution of each of these sources to the total radioactive contamination of water; issues related to excess accumulation of these species; and methods to control TCWS radioactivity within acceptable limits. Among these methods are: (1) water purification to minimize corrosion of materials in contact with TCWS water; (2) monitoring of vital chemistry parameters and control of water chemistry; (3) design of proper building structure and/or TCWS loop/geometry configuration; and (4) design of an ITER liquid radwaste facility tailored to TCWS operational requirements. Design of TCWS nuclear chemistry control is crucial to ensuring that the inventory of radioactive species is consistent with the principle of 'As Low as Reasonably Achievable.'

  6. The effects of gypsy moth defoliation on soil water chemistry

    Treesearch

    Thomas R., Jr. Eagle; Ray R., Jr. Hicks

    1993-01-01

    Twenty-eight plots were established in oak stands along the leading edge of gypsy moth migration into north-central West Virginia. Plots were arranged in a 3-chain square grid pattern in areas of varying aspect, percent slope, elevation, site index and species composition. Soft water, gypsy moth frass and leaf fragments generated by larval feeding were collected weekly...

  7. Integrating Biology, Chemistry, and Mathematics to Evaluate Global Water Problems

    ERIC Educational Resources Information Center

    Kosal, Erica; Lawrence, Carol; Austin, Rodney

    2010-01-01

    An interdisciplinary and context-driven course focused on global water issues was developed and taught at the college level. Students designed a semester-long research project, collected and analyzed data, and ultimately presented their results and conclusions to the larger community. As a result of the course, students' science literacy improved…

  8. Integrating Biology, Chemistry, and Mathematics to Evaluate Global Water Problems

    ERIC Educational Resources Information Center

    Kosal, Erica; Lawrence, Carol; Austin, Rodney

    2010-01-01

    An interdisciplinary and context-driven course focused on global water issues was developed and taught at the college level. Students designed a semester-long research project, collected and analyzed data, and ultimately presented their results and conclusions to the larger community. As a result of the course, students' science literacy improved…

  9. Solute Export Through Transpiration: A Possible Control of Soil Water Chemistry?

    NASA Astrophysics Data System (ADS)

    Alexander, S. C.; Boyle, D. B.; Alexander, E. C.

    2005-12-01

    Recent studies of soil and ground water interactions in western Minnesota have produced seemingly anomalous results. The soil waters beneath highly transpirative plants (Typha sp., Salix sp. and Populus sp.) in a ground water discharge area developed high calcium sulfate concentrations with only minor enrichment of sodium and chloride. It was expected that concentration of solutes by evapo-transpiration would enrich all ions in the originating ground water more equally. Transpired water is generally assumed to be essentially distilled water although there is little analytical data to support this hypothesis. Given the very high evapotranspiration rates of Western Minnesota, greater than 95% of total water movement, even relatively dilute ion concentrations in the transpired water may be significant in the total chemical budget. To investigate the chemistry of transpired water we adapted techniques that have been used to study total transpiration rates as well as isotopic composition of transpired waters. Our initial results from typha sp. have produced waters that while relatively dilute are distinctly not distilled water. Control samples using de-ionized water over dead vegetation produced minor ion enrichment. All results are in ppm. Ion - Ca, Mg, Na, K, P, Mn, Cl , SO4, NO3-N soil water - 18.5, 2.9, 4.8, 3.8, 0.2, 0.2, 5.6, 2.4, 0.5 transpiration - 1.9, 0.6, 1.5, 8.5, 0.3, 0.4, 9.0, 1.6, <0.1 DI control - 0.1, <0.1, 0.1, <0.1, <0.1, <0.1, <0.1, 1.6, <0.1 The observed transpiration chemistries are in rough agreement with reported literature values for plant stem water. While many plants are known to excrete large molecules the expulsion of ions in transpired water would represent a novel chemical plant pathway.

  10. Iodine chemical forms in LWR severe accidents

    SciTech Connect

    Weber, C.F.; Beahm, E.C.; Kress, T.S.

    1991-01-01

    Calculated data from seven severe accident sequences in light water reactor plants were used to assess the chemical forms of iodine in containment. In most of the calculations for the seven sequences, iodine entering containment from the reactor coolant system was almost entirely in the form of CsI with very small contributions of I or HI. The largest fraction of iodine in forms other than CsI was a total of 3.2% as I plus HI. Within the containment, the CsI will deposit onto walls and other surfaces, as well as in water pools, largely in the form of iodide (I{sup {minus}}). The radiation-induced conversion of I{sup {minus}} in water pools into I{sub 2} is strongly dependent on pH. In systems where the pH was controlled above 7, little additional elemental iodine would be produced in the containment atmosphere. When the pH falls below 7, it may be assumed that it is not being controlled and large fractions of iodine as I{sub 2} within the containment atmosphere may be produced. 17 refs., 5 tabs.

  11. Iodine chemical forms in LWR severe accidents

    SciTech Connect

    Beahm, E.C.; Weber, C.F.; Kress, T.S.; Parker, G.W.

    1991-01-01

    Calculated data from seven severe accident sequences in light-water reactor plants were used to assess the chemical forms of iodine in containment. In most of the calculations for the seven sequences, iodine entering containment from the reactor coolant system was almost entirely in the form of CsI with very small contributions of I or HI. The largest fraction of iodine in forms other than CsI was a total of 3.2% as I plus HI. Within the containment, the CsI will deposit onto walls and other surfaces, as well as in water pools, largely in the form of iodide (I{sup {minus}}). The radiation induced conversion of I{sup {minus}} in water pools into I{sub 2} is strongly dependent on pH. In systems where the pH was controlled above 7, little additional elemental iodine would be produced in the containment atmosphere. When the pH falls below 7, it may be assumed that it is not being controlled, and large fractions of iodine as I{sub 2} within the containment atmosphere may be produced. 16 refs.

  12. The role of water chemistry and geomorphic control in the presence of Didymosphenia geminata in Quebec

    NASA Astrophysics Data System (ADS)

    Gillis, C.; Gabor, R. S.; Cullis, J. D.; Ran, L.; Hassan, M. A.

    2010-12-01

    Didymosphenia geminata (didymo), an invasive diatom, was first officially observed and identified in the Matapedia River in Eastern Quebec in July 2006. This Atlantic salmon fishing river has several characteristics shown to favor didymo's ability to form thick, extensive benthic mats, including stable flow and oligotrophic nutrient conditions. Since the incursion, rapid colonization and inter-catchment transfer processes were observed, notably in surrounding watersheds on the Gaspé Peninsula as well as in northern New-Brunswick. All affected watersheds share favorable characteristics for didymo growth, including high light, low nutrient waters, and stable substrate. The nearby North Shore of the St. Lawrence, which also contains rivers with conditions that would favor didymo growth, has not yet shown didymo presence. This system provides a comparison to identify necessary parameters for didymo growth, with differences primarily due to geology-driven water chemistry. Pre-incursion water chemistry was compared between the two regions. Rivers in the region where didymo is present displayed a high alkalinity and corresponding higher pH, due to increases concentrations of magnesium and calcium, than rivers in regions where didymo has not appeared. Also, rivers with didymo show a lower amount of color-causing compounds, such as organic carbon, and clearer water, which supports the theory that high light levels encourage didymo growth. In addition to water chemistry, channel morphology, bed stability and flow patterns are also believed to be key elements in determining the presence of this benthic diatom. In 2007, channel morphology, bed texture, bankfull depth and width, local bed slope and didymo presence were surveyed on a 65 km stretch of the Matapedia River. Relative frequency of didymo presence showed that didymo blooms are most likely to appear in cobble-riffles than in any other morphologies. In fact, cobble riffles promote didymo establishment due to shallow

  13. Ground-Water, Surface-Water, and Water-Chemistry Data, Black Mesa Area, Northeastern Arizona-2005-06

    USGS Publications Warehouse

    Truini, Margot; Macy, J.P.

    2007-01-01

    The N aquifer is the major source of water in the 5,400 square-mile Black Mesa area in northeastern Arizona. Availability of water is an important issue in northeastern Arizona because of continued water requirements for industrial and municipal use and the needs of a growing population. Precipitation in the Black Mesa area averages about 6 to 14 inches per year. The water monitoring program in the Black Mesa area began in 1971 and is designed to provide information about the long-term effects of ground-water withdrawals from the N aquifer for industrial and municipal uses. This report presents results of data collected for the monitoring program in the Black Mesa area from January 2005 to September 2006. The monitoring program includes measurements of (1) ground-water pumping, (2) ground-water levels, (3) spring discharge, (4) surface-water discharge, (5) ground-water chemistry, and (6) periodic testing of ground-water withdrawal meters. In 2005, ground-water withdrawals in the Black Mesa area totaled 7,330 acre-feet, including ground-water withdrawals for industrial (4,480 acre-feet) and municipal (2,850 acre-feet) uses. From 2004 to 2005, total withdrawals increased by less than 2 percent, industrial withdrawals increased by approximately 3 percent, and total municipal withdrawals increased by 0.35 percent. From 2005 to 2006, annually measured water levels in the Black Mesa area declined in 10 of 13 wells in the unconfined areas of the N aquifer, and the median change was -0.5 foot. Measurements indicated that water levels declined in 12 of 15 wells in the confined area of the aquifer, and the median change was -1.4 feet. From the prestress period (prior to 1965) to 2006, the median water-level change for 29 wells was -8.5 feet. Median water-level changes were -0.2 foot for 13 wells in the unconfined areas and -46.6 feet for 16 wells in the confined area. Ground-water discharges were measured once in 2005 and once in 2006 at Moenkopi School Spring and Burro

  14. Water chemistry responses to hydraulic manipulation of an agricultural wetland

    NASA Astrophysics Data System (ADS)

    Powers, S.; Stanley, E. H.

    2011-12-01

    Small impoundments are often crucial factors for the movement of sediment, organic matter, water-borne nutrients, and toxic materials through river networks. By recent accounting, at least 2.6 million small artificial water bodies exist in the US alone. A large proportion of those structures occur in regions with high intensity of agriculture, such as in the Midwestern grain belt. While small impoundments are aging structures which appear to serve few purposes, some hold ecological and biogeochemical value as artificial wetlands. We documented instantaneous net fluxes of solute (chloride, sulfate, nitrate, ammonium, and soluble reactive phosphorus) through an artificial flow-through wetland in agricultural southern Wisconsin over 6 years which spanned removal of a small dam. Phased dewatering and dam removal ultimately converted the artificial wetland to a canal-like state (increase in mean water velocity from 0.08 to 0.22 m s-1). Mean net flux for chloride across the system averaged nearly 0 g d-1, indicating conservative transport and successful characterization of hydrology. In contrast, net fluxes for other solute forms were altered following loss of the wetland: a persistent net sulfate sink (5-10% of inputs retained), suggestive of sulfate-reducing bacteria, was reduced; seasonal (summer) net sinks for nitrate and ammonium, suggestive of uptake by algae and denitrifying bacteria, were reduced; temporal variability for the net flux of soluble reactive phosphorus was reduced. Overall, loss of the artificial wetland caused by dam removal shifted seasonal and annual net fluxes of biologically available solute toward export. Nutrient retention by artificial wetlands could be important for elemental budgets in regions which have high nutrient loading to surface and ground water.

  15. Governing chemistry of cellulose hydrolysis in supercritical water.

    PubMed

    Cantero, Danilo A; Bermejo, M Dolores; Cocero, M José

    2015-03-01

    At extremely low reaction times (0.02 s), cellulose was hydrolyzed in supercritical water (T=400 °C and P=25 MPa) to obtain a sugar yield higher than 95 wt%, whereas the 5-hydroxymethylfurfural (5-HMF) yield was lower than 0.01 wt %. If the reaction time was increased to 1 s, the main product was glycolaldehyde (60 wt%). Independently of the reaction time, the yield of 5-HMF was always lower than 0.01 wt%. To evaluate the reaction mechanism of biomass hydrolysis in pressurized water, several parameters (temperature, pressure, reaction time, and reaction medium) were studied for different biomasses (cellulose, glucose, fructose, and wheat bran). It was found that the H(+) and OH(-) ion concentration in the reaction medium as a result of water dissociation is the determining factor in the selectivity. The reaction of glucose isomerization to fructose and the further dehydration to 5-HMF are highly dependent on the ion concentration. By an increase in the pOH/pH value, these reactions were minimized to allow control of 5-HMF production. Under these conditions, the retroaldol condensation pathway was enhanced, instead of the isomerization/dehydration pathway.

  16. Advanced LWR Nuclear Fuel Cladding System Development Trade-Off Study

    SciTech Connect

    Kristine Barrett; Shannon Bragg-Sitton

    2012-09-01

    The Advanced Light Water Reactor (LWR) Nuclear Fuel Development Research and Development (R&D) Pathway encompasses strategic research focused on improving reactor core economics and safety margins through the development of an advanced fuel cladding system. To achieve significant operating improvements while remaining within safety boundaries, significant steps beyond incremental improvements in the current generation of nuclear fuel are required. Fundamental improvements are required in the areas of nuclear fuel composition, cladding integrity, and the fuel/cladding interaction to allow power uprates and increased fuel burn-up allowance while potentially improving safety margin through the adoption of an “accident tolerant” fuel system that would offer improved coping time under accident scenarios. With a development time of about 20 – 25 years, advanced fuel designs must be started today and proven in current reactors if future reactor designs are to be able to use them with confidence.

  17. LWR Fuel Cycle with Reduced HLW Production

    SciTech Connect

    Darilek, Petr; Necas, Vladimir; Sebian, Vladimir

    2005-05-24

    An advanced fuel cycle of a light water reactor VVER-440 (Russian design) with inert matrix fuel is described. The cycle is based on combined fuel assemblies containing standard uranium pins and transmutation pins with transuranium elements from spent fuel in an inert matrix. This cycle is compared with a standard open fuel cycle based on radially profiled assemblies and with a standard closed fuel cycle containing MOX fuel assemblies. Numerical analysis is based on spectral code HELIOS. Cycle performance indicators covering waste stream parameters and the risk connected with spent fuel are evaluated.

  18. LWR Fuel Cycle with Reduced HLW Production

    NASA Astrophysics Data System (ADS)

    Darilek, Petr; Necas, Vladimir; Sebian, Vladimir

    2005-05-01

    An advanced fuel cycle of a light water reactor VVER-440 (Russian design) with inert matrix fuel is described. The cycle is based on combined fuel assemblies containing standard uranium pins and transmutation pins with transuranium elements from spent fuel in an inert matrix. This cycle is compared with a standard open fuel cycle based on radially profiled assemblies and with a standard closed fuel cycle containing MOX fuel assemblies. Numerical analysis is based on spectral code HELIOS. Cycle performance indicators covering waste stream parameters and the risk connected with spent fuel are evaluated

  19. Twenty years of improvements in LWR safety

    SciTech Connect

    Franks, S. III; Mulkey, J.P.; Deitrich, L.W.; Moonka, A.

    1996-05-01

    Substantial improvements have been made in the safety of light-water reactors in the US during the past two decades, making currently operating reactors safer than ever before. Safety improvements have resulted both from regulatory and operational changes and from new knowledge and technology. The US Nuclear Regulatory Commission, the US Department of Energy, and the American nuclear power industry have worked together and with the international community to enhance the safety of existing plants and to incorporate lessons learned from prior operation into designs for a new generation of advanced, inherently safer reactors.

  20. Rock-Bound Arsenic Influences Ground Water and Sediment Chemistry Throughout New England

    USGS Publications Warehouse

    Robinson,, Gilpin R.; Ayotte, Joseph D.

    2007-01-01

    The information in this report was presented at the Northeastern Region Geological Society of America meeting held March 11-14, 2007, in Durham, New Hampshire. In the New England crystalline bedrock aquifer, concentrations of arsenic that exceed the drinking water standard of 10 ?g/L occur most frequently in ground water from wells sited in specific metamorphic and igneous rock units. Geochemical investigations indicate that these geologic units typically have moderately elevated whole-rock concentrations of arsenic compared to other rocks in the region. The distribution of ground water wells with As > 5 ?g/L has a strong spatial correlation with specific bedrock units where average whole-rock concentrations of arsenic exceed 1.1 mg/kg and where geologic and geochemical factors produce high pH ground water. Arsenic concentrations in stream sediments collected from small drainages reflect the regional distribution of this natural arsenic source and have a strong correlation with both rock chemistry and the distribution of bedrock units with elevated arsenic chemistry. The distribution of ground water wells with As > 5 ?g/L has a strong spatial correlation with the distribution of stream sediments where concentrations of arsenic exceed 6 mg/kg. Stream sediment chemistry also has a weak correlation with the distribution of agricultural lands where arsenical pesticides were used on apple, blueberry, and potato crops. Elevated arsenic concentrations in bedrock wells, however, do not correlate with agricultural areas where arsenical pesticides were used. These results indicate that both stream sediment chemistry and the solubility and mobility of arsenic in ground water in bedrock are influenced by host-rock arsenic concentrations. Stream sediment chemistry and the distribution of geologic units have been found to be useful parameters to predict the areas of greatest concern for elevated arsenic in ground water and to estimate the likely levels of human exposure to

  1. Dominant processes controlling water chemistry of the Pecos River in American southwest

    NASA Astrophysics Data System (ADS)

    Yuan, Fasong; Miyamoto, Seiichi

    2005-09-01

    Here we show an analysis of river flow and water chemistry data from eleven gauging stations along the Pecos River in eastern New Mexico and western Texas, with time spanning 1959-2002. Analysis of spatial relationship between the long-term average flow and total dissolved solids (TDS) concentration allows us to illuminate four major processes controlling river chemistry, namely saline water addition, evaporative concentration with salt gain or loss, dilution with salt gain or loss, and salt storage. Of the 10 river reaches studied, six reaches exhibit the process dominated by evaporative concentration or freshwater dilution with little change in salt load. Four reaches show considerable salt gains or losses that are induced by surface-ground water interactions. This analysis suggests that the evaporative concentration and freshwater dilution are the prevailing mechanisms, but local processes (e.g., variations in hydrologic flowpath and lithologic formation) also play an important role in regulating the hydrochemistry of the Pecos River.

  2. Variation in water chemistry parameters in the Clayburn Creek watershed, British Columbia during fall 2015.

    NASA Astrophysics Data System (ADS)

    Marsh, S. J.; Gillies, S. L.; Peucker-Ehrenbrink, B.; Janmaat, A.; Clemence, E.; Faber, A.; Yakemchuk, A.; McCabe, M.; Toner, A.; Strangway, A.; Turner, S.; Sidhu, D.; Sidhu, B.; Sekhton, J.; Puri, K.; Paulson, D.; Mahil, G.; Leffers, R.; Kanda, S.; Gaultier, M.; Dhaliwal, H.

    2015-12-01

    faculty and students from the University of the Fraser Valley have conducted the time series sampling of water chemistry of the Fraser River at Fort Langley and five Fraser Valley tributaries as a member of the Global Rivers Observatory (GRO, www.globalrivers.org) organized by Woods Hole Oceanographic Institution and Woods Hole Research Center. Clayburn Creek and Willband Creek in Abbotsford, British Columbiahave been part of this project and have been sampled for nutrient and major ion concentrations and parameters such as water temperature, dissolved oxygen, conductivity, pH and turbidity. This watershed is being threatened by increasing anthropogenic activity (agricultural, industrial and residential development) that may threaten the salmon that spawn in this watershed. Documenting the change in the water chemistry in this watershed as the seasons progress from a dry summer to a wet fall will yield a greater understanding of our impact on this watershed and may assist our attempts to protect this watershed.

  3. The key to superior water chemistry at a PWR nuclear station

    SciTech Connect

    Dolan, R.; Miller, L.K.; Olejar, L.L.; Salem, E.

    1983-01-01

    This paper demonstrates how a condensate polishing unit can be successfully used to treat the feedwater for circulating-type pressurized water reactors (PWRs). Water chemistry at the Salem Generating Station, a two-unit, four-loop Westinghouse PWR located in New Jersey, is discussed. Topics considered include a plant description and the history of early operation, the role of constant surveillance, makeup water quality, the effect of freezing on gel-type anion exchange resin, a total organic carbon (TOC) survey, steam generator chemistry, steam generator inspection, condensate polisher operation, and management philosophy. The SEPREX condensate polishing process, in which the complete separation of the anion exchange resin from the cation exchange resin is achieved by flotation separation, is examined. It is concluded that the utilization of a condensate polishing process such as SEPREX provides the operating personnel at the plant with the necessary means to maintain the minimum desired level of contaminants within the steam generator.

  4. Vertical Gradients in Water Chemistry and Age in the Northern High Plains Aquifer, Nebraska, 2003

    USGS Publications Warehouse

    McMahon, P.B.; Böhlke, J.K.; Carney, C.P.

    2007-01-01

    The northern High Plains aquifer is the primary source of water used for domestic, industrial, and irrigation purposes in parts of Colorado, Kansas, Nebraska, South Dakota, and Wyoming. Despite the aquifer's importance to the regional economy, fundamental ground-water characteristics, such as vertical gradients in water chemistry and age, remain poorly defined. As part of the U.S. Geological Survey's National Water-Quality Assessment Program, water samples from nested, short-screen monitoring wells installed in the northern High Plains aquifer were analyzed for major ions, nutrients, trace elements, dissolved organic carbon, pesticides, stable and radioactive isotopes, dissolved gases, and other parameters to evaluate vertical gradients in water chemistry and age in the aquifer. Chemical data and tritium and radiocarbon ages show that water in the aquifer was chemically and temporally stratified in the study area, with a relatively thin zone of recently recharged water (less than 50 years) near the water table overlying a thicker zone of older water (1,800 to 15,600 radiocarbon years). In areas where irrigated agriculture was an important land use, the recently recharged ground water was characterized by elevated concentrations of major ions and nitrate and the detection of pesticide compounds. Below the zone of agricultural influence, major-ion concentrations exhibited small increases with depth and distance along flow paths because of rock/water interactions. The concentration increases were accounted for primarily by dissolved calcium, sodium, bicarbonate, sulfate, and silica. In general, the chemistry of ground water throughout the aquifer was of high quality. None of the approximately 90 chemical constituents analyzed in each sample exceeded primary drinking-water standards. Mass-balance models indicate that changes in ground-water chemistry along flow paths in the aquifer can be accounted for by small amounts of feldspar and calcite dissolution; goethite and

  5. Kinugasa reactions in water: from green chemistry to bioorthogonal labelling.

    PubMed

    Chigrinova, Mariya; MacKenzie, Douglas A; Sherratt, Allison R; Cheung, Lawrence L W; Pezacki, John Paul; Pezacki, Paul

    2015-04-16

    The Kinugasa reaction has become an efficient method for the direct synthesis of β-lactams from substituted nitrones and copper(I) acetylides. In recent years, the reaction scope has been expanded to include the use of water as the solvent, and with micelle-promoted [3+2] cycloadditions followed by rearrangement furnishing high yields of β-lactams. The high yields of stable products under aqueous conditions render the modified Kinugasa reaction amenable to metabolic labelling and bioorthogonal applications. Herein, the development of methods for use of the Kinugasa reaction in aqueous media is reviewed, with emphasis on its potential use as a bioorthogonal coupling strategy.

  6. Reconnaissance of hydrology, land use, ground-water chemistry, and effects of land use on ground-water chemistry in the Albuquerque-Belen basin, New Mexico

    USGS Publications Warehouse

    Anderholm, S.K.

    1987-01-01

    In 1984, the U.S. Geological Survey began regional assessments of groundwater contamination in 14 areas, one of which was the Albuquerque-Belen basin. Groundwater recharge occurs along the basin margins. Groundwater discharge occurs as evapotranspiration in the Rio Grande valley, pumpage, and groundwater flow to the Socorro basin. Open-space land use, which primarily is used for grazing livestock, occupies the majority of the basin. In the Rio Grande valley, agricultural and residential land uses are predominant; in the area near Albuquerque, the land also is used for commercial, institutional , and industrial purposes. The Albuquerque-Belen basin was divided into seven zones on the basis of water chemistry. These water-chemistry zones indicate that large variations in water chemistry exist in the basin as the result of natural processes. Groundwater in the majority of the Albuquerque-Belen basin has a relatively low susceptibility to contamination because the depth to water is > 100 ft and there is virtually no natural mechanism for recharge to the groundwater system. Groundwater in the Rio Grande valley has a relatively high susceptibility to contamination because the depth to water is generally < 30 ft and there are many types of recharge to the groundwater system. Changes in land use may cause changes in the chemical composition of recharge to the groundwater system. The relatively large concentrations of dissolved iron in the Rio Grande valley near Albuquerque may result from the change from agricultural land use to residential land use. Recharge associated with agricultural land use is relatively oxidized because the water is in equilibrium with the atmosphere, whereas recharge associated with residential land use (onsite waste-disposal effluent) is relatively reduced and has larger concentrations of organic carbon, biological oxygen demand, and chemical oxygen demand. The constituents in the onsite waste-disposal effluent could cause reducing conditions in

  7. Environmentally assisted cracking in LWR materials

    SciTech Connect

    Chopra, O.K.; Chung, H.M.; Kassner, T.F.; Park, J.H.; Shack, W.J.; Zhang, J.; Brust, F.W.; Dong, P.

    1998-03-01

    The effect of dissolved oxygen level on fatigue life of austenitic stainless steels is discussed and the results of a detailed study of the effect of the environment on the growth of cracks during fatigue initiation are presented. Initial test results are given for specimens irradiated in the Halden reactor. Impurities introduced by shielded metal arc welding that may affect susceptibility to stress corrosion cracking are described. Results of calculations of residual stresses in core shroud weldments are summarized. Crack growth rates of high-nickel alloys under cyclic loading with R ratios from 0.2--0.95 in water that contains a wide range of dissolved oxygen and hydrogen concentrations at 289 and 320 C are summarized.

  8. Environmentally assisted cracking of LWR materials.

    SciTech Connect

    Chopra, O. K.; Chung, H. M.; Kassner, T. F.; Park, J. H.; Shack, W. J.; Zhang, J.; Brust, F. W.; Dong, P.

    1997-12-05

    The effect of dissolved oxygen level on fatigue life of austenitic stainless steels is discussed and the results of a detailed study of the effect of the environment on the growth of cracks during fatigue initiation are presented. Initial test results are given for specimens irradiated in the Halden reactor. Impurities introduced by shielded metal arc welding that may affect susceptibility to stress corrosion cracking are described. Results of calculations of residual stresses in core shroud weldments are summarized. Crack growth rates of high-nickel alloys under cyclic loading with R ratios from 0.2-0.95 in water that contains a wide range of dissolved oxygen and hydrogen concentrations at 289 and 320 C are summarized.

  9. A fracture mechanics approach for estimating fatigue crack initiation in carbon and low-alloy steels in LWR coolant environments

    SciTech Connect

    Park, H. B.; Chopra, O. K.

    2000-04-10

    A fracture mechanics approach for elastic-plastic materials has been used to evaluate the effects of light water reactor (LWR) coolant environments on the fatigue lives of carbon and low-alloy steels. The fatigue life of such steel, defined as the number of cycles required to form an engineering-size crack, i.e., 3-mm deep, is considered to be composed of the growth of (a) microstructurally small cracks and (b) mechanically small cracks. The growth of the latter was characterized in terms of {Delta}J and crack growth rate (da/dN) data in air and LWR environments; in water, the growth rates from long crack tests had to be decreased to match the rates from fatigue S-N data. The growth of microstructurally small cracks was expressed by a modified Hobson relationship in air and by a slip dissolution/oxidation model in water. The crack length for transition from a microstructurally small crack to a mechanically small crack was based on studies on small crack growth. The estimated fatigue S-N curves show good agreement with the experimental data for these steels in air and water environments. At low strain amplitudes, the predicted lives in water can be significantly lower than the experimental values.

  10. Groundwater chemistry and water-rock interactions at Stripa

    USGS Publications Warehouse

    Nordstrom, D.K.; Ball, J.W.; Donahoe, R.J.; Whittemore, D.

    1989-01-01

    Groundwaters from near surface to a depth of 1232 m in the Stripa granite have been sampled and analyzed for major and trace constituents. The groundwater composition consists of two general types: a typical recharge water of Ca-HCO3 type (700 m depth) of high pH (8-10) that reaches a maximum of 1250 mg/L in total dissolved solids (TDS). Intermediate depths show mixtures of the two types that are highly fracture-dependent rather than depth-dependent. Any borehole can vary significantly and erratically in TDS for either a horizontal or vertical direction. The general transition from Ca-HCO3 type to Na-Ca-Cl type correlates with the depth profile for hydraulic conductivity that drops from 10-8 m/s to 10-11 m/s or lower. Thermomechanical stress (from heater experiments) clearly shows an effect on the groundwater composition that could be caused by changing flow paths, leakage of fluid inclusions or both. Dissolution and precipitation of calcite, fluorite and barite, aluminosilicate hydrolysis, and addition of a saline source (possibly fluid inclusion leakage) play the major roles in defining the groundwater composition. The low permeability of the Stripa granite has produced a groundwater composition that appears intermediate between the dilute, shallow groundwaters typical of recharge in a crystalline rock terrain and the saline waters and brines typical of cratonic shield areas at depth. ?? 1989.

  11. Changes in water chemistry can disable plankton prey defenses.

    PubMed

    Riessen, Howard P; Linley, Robert Dallas; Altshuler, Ianina; Rabus, Max; Söllradl, Thomas; Clausen-Schaumann, Hauke; Laforsch, Christian; Yan, Norman D

    2012-09-18

    The effectiveness of antipredator defenses is greatly influenced by the environment in which an organism lives. In aquatic ecosystems, the chemical composition of the water itself may play an important role in the outcome of predator-prey interactions by altering the ability of prey to detect predators or to implement defensive responses once the predator's presence is perceived. Here, we demonstrate that low calcium concentrations (<1.5 mg/L) that are found in many softwater lakes and ponds disable the ability of the water flea, Daphnia pulex to respond effectively to its predator, larvae of the phantom midge, Chaoborus americanus. This low-calcium environment prevents development of the prey's normal array of induced defenses, which include an increase in body size, formation of neck spines, and strengthening of the carapace. We estimate that this inability to access these otherwise effective defenses results in a 50-186% increase in the vulnerability of the smaller juvenile instars of Daphnia, the stages most susceptible to Chaoborus predation. Such a change likely contributes to the observed lack of success of daphniids in most low-calcium freshwater environments, and will speed the loss of these important zooplankton in lakes where calcium levels are in decline.

  12. Hydrogen mixing study (HMS) in LWR type containments

    SciTech Connect

    Travis, J.R.

    1983-01-01

    A numerical technique has been developed for calculating the full three-dimensional time-dependent Navier-Stokes equations with multiple speies transport. The method is a modified form of the Implicit Continuous-fluid Eulerian (ICE) technique to solve the governing equations for low Mach number flows where pressure waves and local variations in compression and expansion are not significant. Large density variations, due to thermal and species concentration gradients, are accounted for without the restrictions of the classical Boussinesq approximation. Calculations of the EPRI/HEDL standard problems verify the feasibility of using this finite-difference technique for analyzing hydrogen mixing within LWR containments.

  13. Water chemistry of a combined-cycle power plant's auxiliary equipment cooling system

    NASA Astrophysics Data System (ADS)

    Larin, B. M.; Korotkov, A. N.; Oparin, M. Yu.; Larin, A. B.

    2013-04-01

    Results from an analysis of methods aimed at reducing the corrosion rate of structural metal used in heat-transfer systems with water coolant are presented. Data from examination of the closed-circuit system for cooling the auxiliary mechanisms of a combined-cycle plant-based power unit and the results from adjustment of its water chemistry are given. A conclusion is drawn about the possibility of using a reagent prepared on the basis of sodium sulfite for reducing the corrosion rate when the loss of coolant is replenished with nondeaerated water.

  14. The effects of liming an Adirondack lake watershed on downstream water chemistry: Effects of liming on stream chemistry

    USGS Publications Warehouse

    Burns, Douglas A.

    1996-01-01

    Calcite treatment of chronically acidic lakes has improved fish habitat, but the effects on downstream water quality have not previously been examined. In this study, the spatial and temporal effects of watershed CaCO3 treatment on the chemistry of a lake outlet stream in the Adirondack Mountains of New York were examined. Before CaCO3 treatment, the stream was chronically acidic. During spring snowmelt before treatment, pH and acid-neutralizing capacity (ANC) in the outlet stream declined, and NO3- and inorganic monomeric aluminum (AlIM) concentrations increased sharply. During that summer, SO42- and NO3- concentrations decreased downstream, and dissolved organic carbon (DOC) concentrations and ANC increased, in association with the seasonal increase in decomposition of organic matter and the attendant SO42--reduction process. A charge-balance ANC calculation closely matched measured downstream changes in ANC in the summer and indicated that SO42- reduction was the major process contributing to summer increases in ANC. Increases in Ca2+ concentration and ANC began immediately after CaCO3 application, and within 3 months, exceeded their pretreatment values by more than 130 ??eq/L. Within 2 months after treatment, downstream decreases in Ca2+ concentration, ANC, and pH, were noted. Stream mass balances between the lake and the sampling site 1.5 km downstream revealed that the transport of all chemical constituents was dominated by conservative mixing with tributaries and ground water; however, non-conservative processes resulted in significant Ca2+ losses during the 13-month period after CaCO3 treatment. Comparison of substrate samples from the buffered outlet stream with those from its untreated tributaries showed that the percentage of cation-exchange sites occupied by Ca2+, as well as non-exchangeable Ca, were higher in the outlet-stream substrate than in tributary-stream substrate. Mass-balance data for Ca2+, H+, AlIM, and DOC revealed net downstream losses of

  15. Geohydrological characterization, water-chemistry, and ground-water flow simulation model of the Sonoma Valley area, Sonoma County, California

    USGS Publications Warehouse

    Farrar, Christopher D.; Metzger, Loren F.; Nishikawa, Tracy; Koczot, Kathryn M.; Reichard, Eric G.; Langenheim, V.E.

    2006-01-01

    The Sonoma Valley, located about 30 miles north of San Francisco, is one of several basins in Sonoma County that use a combination of ground water and water delivered from the Russian River for supply. Over the past 30 years, Sonoma Valley has experienced rapid population growth and land-use changes. In particular, there has been a significant increase in irrigated agriculture, predominantly vineyards. To provide a better understanding of the ground-water/surface-water system in Sonoma Valley, the U.S. Geological Survey compiled and evaluated existing data, collected and analyzed new data, and developed a ground-water flow model to better understand and manage the ground-water system. The new data collected include subsurface lithology, gravity measurements, groundwater levels, streamflow gains and losses, temperature, water chemistry, and stable isotopes. Sonoma Valley is drained by Sonoma Creek, which discharges into San Pablo Bay. The long-term average annual volume of precipitation in the watershed is estimated to be 269,000 acre-feet. Recharge to the ground-water system is primarily from direct precipitation and Sonoma Creek. Discharge from the ground-water system is predominantly outflow to Sonoma Creek, pumpage, and outflow to marshlands and to San Pablo Bay. Geologic units of most importance for groundwater supply are the Quaternary alluvial deposits, the Glen Ellen Formation, the Huichica Formation, and the Sonoma Volcanics. In this report, the ground-water system is divided into three depth-based geohydrologic units: upper (less than 200 feet below land surface), middle (between 200 and 500 feet), and lower (greater than 500 feet). Synoptic streamflow measurements were made along Sonoma Creek and indicate those reaches with statistically significant gains or losses. Changes in ground-water levels in wells were analyzed by comparing historical contour maps with the contour map for 2003. In addition, individual hydrographs were evaluated to assess temporal

  16. Martian atmospheric chemistry during the time of low water abundance

    NASA Technical Reports Server (NTRS)

    Nair, Hari; Allen, Mark; Yung, Yuk L.; Clancy, R. Todd

    1992-01-01

    The importance of odd hydrogen (or HO(x)) radicals in the catalytic recombination of carbon monoxide and oxygen in the Martian atmosphere is a well known fact. The inclusion of recent chemical kinetics data, specifically temperature-dependent CO2 absorption cross sections, into our one dimensional photochemical model shows that HO(x) is too efficient in this regard. The absorption cross sections of CO2 are smaller than previously assumed; this leads to a reduction in the photolysis rate of CO2 while the photolysis rate of H2O has increased. As a consequence the predicted mixing ratio of CO in our models is substantially less than the observed value of 6.5(10)(exp -4). Simultaneous measurements of water, ozone, and carbon monoxide were obtained in the Martian atmosphere in early Dec. 1990 (L(sub s) for Mars was 344 deg.).

  17. Martian atmospheric chemistry during the time of low water abundance

    NASA Technical Reports Server (NTRS)

    Nair, Hari; Allen, Mark; Yung, Yuk L.; Clancy, R. Todd

    1992-01-01

    The importance of odd hydrogen (or HO(x)) radicals in the catalytic recombination of carbon monoxide and oxygen in the Martian atmosphere is a well known fact. The inclusion of recent chemical kinetics data, specifically temperature-dependent CO2 absorption cross sections, into our one dimensional photochemical model shows that HO(x) is too efficient in this regard. The absorption cross sections of CO2 are smaller than previously assumed; this leads to a reduction in the photolysis rate of CO2 while the photolysis rate of H2O has increased. As a consequence the predicted mixing ratio of CO in our models is substantially less than the observed value of 6.5(10)(exp -4). Simultaneous measurements of water, ozone, and carbon monoxide were obtained in the Martian atmosphere in early Dec. 1990 (L(sub s) for Mars was 344 deg.).

  18. Trends in precipitation and stream-water chemistry in the northeastern United States, water years 1984-96

    USGS Publications Warehouse

    Clow, D.W.; Mast, M. Alisa

    1999-01-01

    Trends in precipitation and stream-water chemistry during water years 1984-96 were examined at eight precipitation monitoring sites and five nearby streams operated by the U.S. Geological Survey in the northeastern United States. The statistical analyses indicate the following: 1)Stream-water sulfate (SO4) concentrations decreased at seven of eight precipitation monitoring sites and in each of five streams. 2)Calcium plus magnesium (Ca + Mg) concentrations decreased at seven of eight precipitation monitoring sites and in three of five streams. 3)Precipitation acidity decreased at five of eight precipitation monitoring sites, but alkalinity increased in only one stream. These results indicate that decreases in atmospheric deposition of SO4 have resulted in decreased precipitation acidity. The chemical response of stream water to changes in precipitation chemistry was complex. Decreases in stream-water SO4 concentrations generally matched decreases of precipitation SO4. In stream water, increases in alkalinity were uncommon because decreases in SO4 concentrations often were accompanied by decreases in Ca + Mg concentrations. The decreases in Ca + Mg concentrations might be related to depletion of base cations from soil caused by long-term exposure to acidic deposition. Increases in streamwater alkalinity might not occur until rates of acidic deposition are reduced to substantially less than the rate of cation resupply by weathering and atmospheric deposition. In areas where forests are aggrading, recovery of stream-water alkalinity will be delayed further because of the acidifying effect of biomass accumulation.

  19. Water-stable fac-{TcO₃}⁺ complexes - a new field of technetium chemistry.

    PubMed

    Braband, Henrik

    2011-01-01

    The development of technetium chemistry has been lagging behind that of its heavier congener rhenium, primarily because the inherent radioactivity of all Tc isotopes has limited the number of laboratories that can study the chemistry of this fascinating element. Although technetium is an artificial element, it is not rare. Significant amounts of the isotope (99)Tc are produced every day as a fission byproduct in nuclear power plants. Therefore, a fundamental understanding of the chemistry of (99)Tc is essential to avoid its release into the environment. In this article the chemistry of technetium at its highest oxidation state (+VII) is reviewed with a special focus on recent developments which make water-stable complexes of the general type [TcO(3)(tacn-R)](+) (tacn-R = 1,4,7-triazacyclononane or derivatives) accessible. Complexes containing the fac-{TcO(3)}(+) core display a unique reactivity. In analogy to [OsO(4)] and [RuO(4)], complexes containing the fac-{TcO(3)}(+) core undergo with alkenes metal-mediated, vicinal cis-dihydroxylation reactions (alkene-glycol interconversion) in water via a (3+2)-cycloaddition reaction. Therefore, water-stable fac-{(99m)TcO(3)}(+) complexes pave the way for a new labeling strategy for radiopharmaceutical applications, based on (3+2)-cycloaddition reactions. This new concept for the labeling of biomolecules with small [(99m)TcO(3)(tacn-R)](+)-type complexes by way of a (3+2)-cycloaddition with alkenes is discussed in detail. The herein reported developments in high-valent technetium chemistry create a new field of research with this artificial element. This demonstrates the potential of fundamental research to provide new impetus of innovation for the development of new methods for radiopharmaceutical applications.

  20. A classification scheme for LWR fuel assemblies

    SciTech Connect

    Moore, R.S.; Williamson, D.A.; Notz, K.J.

    1988-11-01

    With over 100 light water nuclear reactors operating nationwide, representing designs by four primary vendors, and with reload fuel manufactured by these vendors and additional suppliers, a wide variety of fuel assembly types are in existence. At Oak Ridge National Laboratory, both the Systems Integration Program and the Characteristics Data Base project required a classification scheme for these fuels. This scheme can be applied to other areas and is expected to be of value to many Office of Civilian Radioactive Waste Management programs. To develop the classification scheme, extensive information on the fuel assemblies that have been and are being manufactured by the various nuclear fuel vendors was compiled, reviewed, and evaluated. It was determined that it is possible to characterize assemblies in a systematic manner, using a combination of physical factors. A two-stage scheme was developed consisting of 79 assembly types, which are grouped into 22 assembly classes. The assembly classes are determined by the general design of the reactor cores in which the assemblies are, or were, used. The general BWR and PWR classes are divided differently but both are based on reactor core configuration. 2 refs., 15 tabs.

  1. LWR codes capability to address SFR BDBA scenarios: Modeling of the ABCOVE tests

    SciTech Connect

    Herranz, L. E.; Garcia, M.; Morandi, S.

    2012-07-01

    The sound background built-up in LWR source term analysis in case of a severe accident, make it worth to check the capability of LWR safety analysis codes to model accident SFR scenarios, at least in some areas. This paper gives a snapshot of such predictability in the area of aerosol behavior in containment. To do so, the AB-5 test of the ABCOVE program has been modeled with 3 LWR codes: ASTEC, ECART and MELCOR. Through the search of a best estimate scenario and its comparison to data, it is concluded that even in the specific case of in-containment aerosol behavior, some enhancements would be needed in the LWR codes and/or their application, particularly with respect to consideration of particle shape. Nonetheless, much of the modeling presently embodied in LWR codes might be applicable to SFR scenarios. These conclusions should be seen as preliminary as long as comparisons are not extended to more experimental scenarios. (authors)

  2. On the pore water chemistry effect on spectral induced polarization measurements in the presence of pyrite

    NASA Astrophysics Data System (ADS)

    Placencia-Gómez, Edmundo; Slater, Lee D.

    2016-12-01

    In order to expand the application of the induced polarization (IP) method as a technique for monitoring metallic mineral dissolution and precipitation mechanisms, we studied the effects of variations in pore water chemistry on the spectral induced polarization (SIP) response of a mixture of silica-sand and pyrite particles in the laboratory. We investigated the dependence of the SIP response on both pore water conductivity and pH for various chemical compositions: redox-passive (P) versus redox-active (A) ions, using CaCl2 as P-ions, and FeSO4 and FeCl3 as A-ion brines. The effect of pore water chemistry was evaluated by means of a recently proposed volumetric specific capacitance model. The SIP response (IP-effect) was primarily determined by the pore water conductivity and the specific capacitance was only weakly dependent on the chemical composition and pHw. We found that the specific capacitance varies to first order over a limited range and approximates a single value (≈ 302 F m- 3 in average). However, variations in the specific capacitance as a function of active versus inactive ion chemistry might be important to consider when using IP to monitor specific mineral dissolution and precipitation processes.

  3. Uranium release from sediment to groundwater: influence of water chemistry and insights into release mechanisms.

    PubMed

    Alam, Md Samrat; Cheng, Tao

    2014-08-01

    Uranium (U) contamination in groundwater often results from natural geochemical processes such as mineral dissolution and desorption of adsorbed U from mineral surface. Although U adsorption and U mineral dissolution have been extensively studied, current knowledge of minerals and water chemistry conditions that control U release in uncontaminated soil and aquifers is still limited. Identification of these minerals and the knowledge of how water chemistry conditions influence U release is critical to better understand, predict, and manage geogenic U contamination in soil and groundwater. The objective of this study is to determine the extent and mechanisms of U release from a heterogeneous natural sediment under water chemistry conditions relevant to natural soil water and groundwater. A sediment sample was collected and characterized by XRD, SEM-EDX and extraction methods, and examined using laboratory leaching experiments. Our results show that Fe-Mn (oxy)hydroxides and silicate minerals are the major U hosting minerals, and a substantial fraction of U exists as adsorbed ions on minerals. We also found that U release is controlled by a number of interactive processes including dissolution of U-bearing minerals, U desorption from mineral surface, formation of aqueous U complexes, and reductive precipitation of U. Results from this study shed light on the important geochemical reactions that need be considered for developing a conceptual model that predicts U contamination in subsurface environment. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Regional characters of cloud water chemistry over severe acid rain areas of China

    SciTech Connect

    Zhilai Shen; Hui Xiao; Hengchi Lei; Meiyuan Huang

    1996-12-31

    The results and discussion are presented of measurements of cloud water chemistry made over severe add rain areas, such as Chongqing, Chengdu, Guiyang, Guangzhou, Nanchang, and Changsha in China from 1985 to 1993. Analyses indicate that acid cloud water is widespread in these areas, the range of cloud water pH is large within an area, the highest acidity is not over big city, and the difference of average values of pH is not obvious in different areas. In some areas, for example Chongqing, the annual variation of average pH is large. The range of average of total ion concentrations of cloud water is also large and the maximum is six more than minimum. The relationship between the acidity and ion concentration of cloud water is unlinear. The chemistry parameters of cloud water exhibit an obvious region character in Southwest China (Chongqing, Chengdu and Guiyang) SO4= is a dominant anion and SO4=/NO3- is more than 8, Ca++ and NH4+ are the main cation, Ca++/NH4+>1 (in the remaining areas, Ca++/NH4+<1), the cloud water acidity is higher than that of ground rain, indicating that there is an acidification process below cloud. In South China (Guangzhou and Guiyang) NO3 is same important as SO4= and SO4=/NO3- is about 1. In Central China (Nanchang and Changsha) the total ion concentration is highest on comparison with other areas and the value is more than that of ground rainwater, meaning probably that there is an influence of cloud microphysical process on cloud water and rainwater chemistry.

  5. Geohydrology and water-chemistry of the Alexander Valley, Sonoma County, California

    USGS Publications Warehouse

    Metzger, Loren F.; Farrar, Christopher D.; Koczot, Kathryn M.; Reichard, Eric G.

    2006-01-01

    This study of the geohydrology and water chemistry of the Alexander Valley, California, was done to provide an improved scientific basis for addressing emerging water-management issues, including potential increases in water demand and changes in flows in the Russian River. The study tasks included (1) evaluation of existing geohydrological, geophysical, and geochemical data; (2) collection and analysis of new geohydrologic data, including subsurface lithologic data, ground-water levels, and streamflow records; and (3) collection and analysis of new water-chemistry data. The estimated total water use for the Alexander Valley for 1999 was approximately 15,800 acre-feet. About 13,500 acre-feet of this amount was for agricultural use, primarily vineyards, and about 2,300 acre-feet was for municipal/industrial use. Ground water is the main source of water supply for this area. The main sources of ground water in the Alexander Valley are the Quaternary alluvial deposits, the Glen Ellen Formation, and the Sonoma Volcanics. The alluvial units, where sufficiently thick and saturated, comprise the best aquifer in the study area. Average recharge to the Alexander Valley is estimated from a simple, basinwide water budget. On the basis of an estimated annual average of 298,000 acre-feet of precipitation, 160,000 acre-feet of runoff, and 113,000 to 133,000 acre-feet of evapotranspiration, about 5,000 to 25,000 acre-feet per year is available for ground-water recharge. Because this estimate is based on differences between large numbers, there is significant uncertainty in this recharge estimate. Long-term changes in ground-water levels are evident in parts of the study area, but because of the sparse network and lack of data on well construction and lithology, it is uncertain if any significant changes have occurred in the northern part of the study area since 1980. In the southern half of the study area, ground-water levels generally were lower at the end of the 2002 irrigation

  6. A Review and Analysis of European Industrial Experience in Handling LWR Spent Fuel and Vitrified High-Level Waste

    SciTech Connect

    Blomeke, J.O.

    2001-07-10

    The industrial facilities that have been built or are under construction in France, the United Kingdom, Sweden, and West Germany to handle light-water reactor (LWR) spent fuel and canisters of vitrified high-level waste before ultimate disposal are described and illustrated with drawings and photographs. Published information on the operating performance of these facilities is also given. This information was assembled for consideration in planning and design of similar equipment and facilities needed for the Federal Waste Management System in the United States.

  7. [Relationship between atmospheric particles and rain water chemistry character].

    PubMed

    Huo, Ming-Qun; Sun, Qian; Xie, Peng; Bai, Yu-Hua; Liu, Zhao-Rong; Li, Ji-Long; Lu, Si-Hua

    2009-11-01

    Rain and atmospheric particle samples were collected in the rural area of Taian and Shenzhen in 2007, respectively. Rain sampling was carried out during the precipitation process and several samples were got from the beginning of one precipitation to the end. The chemical character changes during precipitation and the changes of concentration of particles before and after rain were studied in this research to understand the contribution of particles on the rain chemical character and the rain-out effect for particles. The volume-weighted mean pH of rainwater in Taian was 5.97 and the total concentration of ions was 1 187.96 microeq x L(-1). The mass concentration of PM10 in Taian was 131.76 microg/m3 and that of PM2.5 was 103.84 microg/m3. The volume-weighted mean pH of rainwater in Shenzhen was 4.72 and the total concentration of ions was 175.89 microeq x L(-1). The mass concentration of PM10 in Shenzhen was 56.66 microg/m3 and that of PM2.5 was 41.52 microg/m3. During precipitation process pH and ion concentration of rain decrease and it is shown the neutralizing effect happens. The difference between rainwater of Taian and Shenzhen is due to cloud water acidity, atmospheric particles character and atmospheric acid-basic gases concentration. The clean-up effect of Na+ and Ca2+ by rain is high and which of NH4+ and NO3- is low. The clean-up effect for mass concentration, ions concentration and element concentration of particles by rain are significant.

  8. The calculation of aquifer chemistry in hot-water geothermal systems

    USGS Publications Warehouse

    Truesdell, Alfred H.; Singers, Wendy

    1974-01-01

    The temperature and chemical conditions (pH, gas pressure, and ion activities) in a geothermal aquifer supplying a producing bore can be calculated from the enthalpy of the total fluid (liquid + vapor) produced and chemical analyses of water and steam separated and collected at known pressures. Alternatively, if a single water phase exists in the aquifer, the complete analysis (including gases) of a sample collected from the aquifer by a downhole sampler is sufficient to determine the aquifer chemistry without a measured value of the enthalpy. The assumptions made are that the fluid is produced from a single aquifer and is homogeneous in enthalpy and chemical composition. These calculations of aquifer chemistry involving large amounts of ancillary information and many iterations require computer methods. A computer program in PL-1 to perform these calculations is available from the National Technical Information Service as document PB-219 376.

  9. Case study of hydrogen water chemistry implementation at the Duane Arnold Energy Center

    SciTech Connect

    Leibel, T.A.; Turley, D.S. ); Steen, A. )

    1989-01-01

    This paper presents a case study of the hydrogen water chemistry (HWC) program implemented at Duane Arnold Energy Center (DAEC). In 1985 various reactor recirculation system piping weld repairs and safe end replacements were performed at the DAEC. These weld repairs and safe-end replacements were required as a result of inter-granular stress corrosion cracking (IGSCC). In 1986, the utility decided to implement a hydrogen water chemistry program as a means of suppressing IGSCC. The paper includes a discussion of the system design basis, a brief system description, and a discussion of plant system interactions. A description of methodology developed to verify and monitor the effectiveness of the HWC system is also included.

  10. Evaluation of the /sup 252/Cf-source-driven neutron noise analysis method for measuring the subcriticality of LWR fuel storage casks

    SciTech Connect

    Mihalczo, J.T.

    1987-01-01

    The /sup 252/Cf-source-driven neutron noise analysis method was evaluated to determine if it could be used to measure the subcriticality of storage casks of burnt light water reactor (LWR) fuel submerged in fuel storage pools, fully loaded and as they are being loaded. Measurements of k/sub eff/ would provide the parameter most directly related to the criticality safety of storage cask configurations of LWR fuel and could allow proper credit for fuel burnup without reliance on calculations. This, in turn, could lead to more cost-effective cask designs. Evaluation of the method for this application was based on experiments already completed at a critical experiments facility using arrays of pressurized water reactor (PWR) fuel pins typical of the size of storage cask configurations, the existence of neutron detectors that can function in shipping cask environments, and the ability to construct ionization chambers containing /sup 252/Cf of adequate intensity for these measurements.

  11. LWR and defectivity improvement on EUV track system

    NASA Astrophysics Data System (ADS)

    Harumoto, Masahiko; Stokes, Harold; Thouroude, Yan; Kaneyama, Koji; Pieczulewski, Charles; Asai, Masaya

    2016-03-01

    EUV lithography (EUVL) is well known to be a strong candidate for next generation, single exposure sub-30nm halfpitch lithography.[1] Furthermore, high-NA EUV exposure tool(s) released two years ago gave a strong impression by finer pattern results. On the other hand, it seems that the coat-develop track process remains very similar and in many aspects returns to KrF or ArF dry process fundamentals, but in practice a 26-32nm pitch patterning coat develop track process also has challenges with EUV resists. As access to EUV lithography exposures has become more readily available over the last five (5) years, several challenges and accomplishments in the track process have been reported, such as the improvement of ultra-thin film coating, CD uniformity, defectivity, line width roughness (LWR), and so on.[2-8] The coat-develop track process has evolved along with novel materials and metrology capability. Line width roughness (LWR) control and defect reduction are demonstrated utilizing the SOKUDO DUO coat-develop track system with ASML NXE:3100 and NXE:3300 exposures in the IMEC (Leuven, Belgium) cleanroom environment. Additionally, we will show the latest lithographic results obtained by novel processing approaches in the EUV coat develop track system.

  12. FMDP reactor alternative summary report: Volume 4, Evolutionary LWR alternative

    SciTech Connect

    1996-09-01

    Significant quantities of weapons-usable fissile materials [primarily plutonium and highly enriched uranium (HEU)] have become surplus to national defense needs both in the United States and Russia. These stocks of fissile materials pose significant dangers to national and international security. The dangers exist not only in the potential proliferation of nuclear weapons but also in the potential for environmental, safety, and health (ES&H) consequences if surplus fissile materials are not properly managed. The purpose of this report is to provide schedule, cost, and technical information that will be used to support the Record of Process (ROD). Following the screening process, DOE/MD via its national laboratories initiated a more detailed analysis activity to further evaluate each of the ten plutonium disposition alternatives that survived the screening process. Three ``Alternative Teams,`` chartered by DOE and comprised of technical experts from across the DOE national laboratory complex, conducted these analyses. One team was chartered for each of the major disposition classes (borehole, immobilization, and reactors). During the last year and a half, the Fissile Materials Disposition Program (FMDP) Reactor Alternative Team (RxAT) has conducted extensive analyses of the cost, schedule, technical maturity, S&S, and other characteristics of reactor-based plutonium disposition. The results of the RxAT`s analyses of the existing LWR, CANDU, and partially complete LWR alternatives are documented in Volumes 1-3 of this report. This document (Volume 4) summarizes the results of these analyses for the ELWR-based plutonium disposition option.

  13. Introduction of Mass Spectrometry in an First-Semester General Chemistry Laboratory Course: Quantification of Mtbe or Dmso in Water

    ERIC Educational Resources Information Center

    Solow, Mike

    2004-01-01

    Quantification of a contaminant in water provides the first-year general chemistry students with a tangible application of mass spectrometry. The relevance of chemistry to assessing and solving environmental problems is highlighted for students when they perform mass spectroscopy experiments.

  14. Introduction of Mass Spectrometry in an First-Semester General Chemistry Laboratory Course: Quantification of Mtbe or Dmso in Water

    ERIC Educational Resources Information Center

    Solow, Mike

    2004-01-01

    Quantification of a contaminant in water provides the first-year general chemistry students with a tangible application of mass spectrometry. The relevance of chemistry to assessing and solving environmental problems is highlighted for students when they perform mass spectroscopy experiments.

  15. 2015 AAAR Conference Symposium: "The Role of Water in Aerosol Chemistry"

    SciTech Connect

    McNeill, V. Faye; Weber, Rodney

    2015-10-16

    The DOE-sponsored symposium, "The Role of Water in Aerosol Chemistry" was held at the 2015 Annual meeting of AAAR. The funding supported, in part, travel, lodging, and registration expenses for invited symposium speakers, and travel and lodging expenses allowing students to attend and make presentations at a special conference symposium that focuses on topics of interest to the U.S. DOE Atmospheric System Research (ASR) program.

  16. Precipitation chemistry - Atmospheric loadings to the surface waters of the Indian River lagoon basin by rainfall

    NASA Technical Reports Server (NTRS)

    Dreschel, Thomas W.; Madsen, Brooks C.; Maull, Lee A.; Hinkle, C. R.; Knott, William M., III

    1990-01-01

    Rain volume and chemistry monitoring as part of the Kennedy Space Center Long Term Environmental Monitoring Program included the years 1984-1987 as part of the National Atmospheric Deposition Program. Atmospheric deposition in rainfall consisted primarily of sea salt and hydrogen ion, sulfate, nitrate, and ammonium ions. The deposition of nitrogen (a principal plant nutrient) was on the order of 200-300 metric tons per year to the surface waters.

  17. The Unique Chemistry of Eastern Mediterranean Water Masses Selects for Distinct Microbial Communities by Depth

    PubMed Central

    Techtmann, Stephen M.; Fortney, Julian L.; Ayers, Kati A.; Joyner, Dominique C.; Linley, Thomas D.; Pfiffner, Susan M.; Hazen, Terry C.

    2015-01-01

    The waters of the Eastern Mediterranean are characterized by unique physical and chemical properties within separate water masses occupying different depths. Distinct water masses are present throughout the oceans, which drive thermohaline circulation. These water masses may contain specific microbial assemblages. The goal of this study was to examine the effect of physical and geological phenomena on the microbial community of the Eastern Mediterranean water column. Chemical measurements were combined with phospholipid fatty acid (PLFA) analysis and high-throughput 16S rRNA sequencing to characterize the microbial community in the water column at five sites. We demonstrate that the chemistry and microbial community of the water column were stratified into three distinct water masses. The salinity and nutrient concentrations vary between these water masses. Nutrient concentrations increased with depth, and salinity was highest in the intermediate water mass. Our PLFA analysis indicated different lipid classes were abundant in each water mass, suggesting that distinct groups of microbes inhabit these water masses. 16S rRNA gene sequencing confirmed the presence of distinct microbial communities in each water mass. Taxa involved in autotrophic nitrogen cycling were enriched in the intermediate water mass suggesting that microbes in this water mass may be important to the nitrogen cycle of the Eastern Mediterranean. The Eastern Mediterranean also contains numerous active hydrocarbon seeps. We sampled above the North Alex Mud Volcano, in order to test the effect of these geological features on the microbial community in the adjacent water column. The community in the waters overlaying the mud volcano was distinct from other communities collected at similar depths and was enriched in known hydrocarbon degrading taxa. Our results demonstrate that physical phenomena such stratification as well as geological phenomena such as mud volcanoes strongly affect microbial

  18. The unique chemistry of Eastern Mediterranean water masses selects for distinct microbial communities by depth

    DOE PAGES

    Techtmann, Stephen M.; Fortney, Julian L.; Ayers, Kati A.; ...

    2015-03-25

    The waters of the Eastern Mediterranean are characterized by unique physical and chemical properties within separate water masses occupying different depths. Distinct water masses are present throughout the oceans, which drive thermohaline circulation. These water masses may contain specific microbial assemblages. The goal of this study was to examine the effect of physical and geological phenomena on the microbial community of the Eastern Mediterranean water column. Chemical measurements were combined with phospholipid fatty acid (PLFA) analysis and high-throughput 16S rRNA sequencing to characterize the microbial community in the water column at five sites. We demonstrate that the chemistry and microbialmore » community of the water column were stratified into three distinct water masses. The salinity and nutrient concentrations vary between these water masses. Nutrient concentrations increased with depth, and salinity was highest in the intermediate water mass. Our PLFA analysis indicated different lipid classes were abundant in each water mass, suggesting that distinct groups of microbes inhabit these water masses. 16S rRNA gene sequencing confirmed the presence of distinct microbial communities in each water mass. Taxa involved in autotrophic nitrogen cycling were enriched in the intermediate water mass suggesting that microbes in this water mass may be important to the nitrogen cycle of the Eastern Mediterranean. The Eastern Mediterranean also contains numerous active hydrocarbon seeps. We sampled above the North Alex Mud Volcano, in order to test the effect of these geological features on the microbial community in the adjacent water column. The community in the waters overlaying the mud volcano was distinct from other communities collected at similar depths and was enriched in known hydrocarbon degrading taxa. Furthermore, our results demonstrate that physical phenomena such stratification as well as geological phenomena such as mud volcanoes strongly

  19. The unique chemistry of Eastern Mediterranean water masses selects for distinct microbial communities by depth

    SciTech Connect

    Techtmann, Stephen M.; Fortney, Julian L.; Ayers, Kati A.; Joyner, Dominique C.; Linley, Thomas D.; Pfiffner, Susan M.; Hazen, Terry C.; Thompson, Fabiano

    2015-03-25

    The waters of the Eastern Mediterranean are characterized by unique physical and chemical properties within separate water masses occupying different depths. Distinct water masses are present throughout the oceans, which drive thermohaline circulation. These water masses may contain specific microbial assemblages. The goal of this study was to examine the effect of physical and geological phenomena on the microbial community of the Eastern Mediterranean water column. Chemical measurements were combined with phospholipid fatty acid (PLFA) analysis and high-throughput 16S rRNA sequencing to characterize the microbial community in the water column at five sites. We demonstrate that the chemistry and microbial community of the water column were stratified into three distinct water masses. The salinity and nutrient concentrations vary between these water masses. Nutrient concentrations increased with depth, and salinity was highest in the intermediate water mass. Our PLFA analysis indicated different lipid classes were abundant in each water mass, suggesting that distinct groups of microbes inhabit these water masses. 16S rRNA gene sequencing confirmed the presence of distinct microbial communities in each water mass. Taxa involved in autotrophic nitrogen cycling were enriched in the intermediate water mass suggesting that microbes in this water mass may be important to the nitrogen cycle of the Eastern Mediterranean. The Eastern Mediterranean also contains numerous active hydrocarbon seeps. We sampled above the North Alex Mud Volcano, in order to test the effect of these geological features on the microbial community in the adjacent water column. The community in the waters overlaying the mud volcano was distinct from other communities collected at similar depths and was enriched in known hydrocarbon degrading taxa. Furthermore, our results demonstrate that physical phenomena such stratification as well as geological phenomena such as mud volcanoes strongly affect

  20. The unique chemistry of Eastern Mediterranean water masses selects for distinct microbial communities by depth.

    PubMed

    Techtmann, Stephen M; Fortney, Julian L; Ayers, Kati A; Joyner, Dominique C; Linley, Thomas D; Pfiffner, Susan M; Hazen, Terry C

    2015-01-01

    The waters of the Eastern Mediterranean are characterized by unique physical and chemical properties within separate water masses occupying different depths. Distinct water masses are present throughout the oceans, which drive thermohaline circulation. These water masses may contain specific microbial assemblages. The goal of this study was to examine the effect of physical and geological phenomena on the microbial community of the Eastern Mediterranean water column. Chemical measurements were combined with phospholipid fatty acid (PLFA) analysis and high-throughput 16S rRNA sequencing to characterize the microbial community in the water column at five sites. We demonstrate that the chemistry and microbial community of the water column were stratified into three distinct water masses. The salinity and nutrient concentrations vary between these water masses. Nutrient concentrations increased with depth, and salinity was highest in the intermediate water mass. Our PLFA analysis indicated different lipid classes were abundant in each water mass, suggesting that distinct groups of microbes inhabit these water masses. 16S rRNA gene sequencing confirmed the presence of distinct microbial communities in each water mass. Taxa involved in autotrophic nitrogen cycling were enriched in the intermediate water mass suggesting that microbes in this water mass may be important to the nitrogen cycle of the Eastern Mediterranean. The Eastern Mediterranean also contains numerous active hydrocarbon seeps. We sampled above the North Alex Mud Volcano, in order to test the effect of these geological features on the microbial community in the adjacent water column. The community in the waters overlaying the mud volcano was distinct from other communities collected at similar depths and was enriched in known hydrocarbon degrading taxa. Our results demonstrate that physical phenomena such stratification as well as geological phenomena such as mud volcanoes strongly affect microbial

  1. Ice Thermal Storage Systems for LWR Supplemental Cooling and Peak Power Shifting

    SciTech Connect

    Haihua Zhao; Hongbin Zhang; Phil Sharpe; Blaise Hamanaka; Wei Yan; WoonSeong Jeong

    2010-06-01

    Availability of enough cooling water has been one of the major issues for the nuclear power plant site selection. Cooling water issues have frequently disrupted the normal operation at some nuclear power plants during heat waves and long draught. The issues become more severe due to the new round of nuclear power expansion and global warming. During hot summer days, cooling water leaving a power plant may become too hot to threaten aquatic life so that environmental regulations may force the plant to reduce power output or even temporarily to be shutdown. For new nuclear power plants to be built at areas without enough cooling water, dry cooling can be used to remove waste heat directly into the atmosphere. However, dry cooling will result in much lower thermal efficiency when the weather is hot. One potential solution for the above mentioned issues is to use ice thermal storage systems (ITS) that reduce cooling water requirements and boost the plant’s thermal efficiency in hot hours. ITS uses cheap off-peak electricity to make ice and uses those ice for supplemental cooling during peak demand time. ITS is suitable for supplemental cooling storage due to its very high energy storage density. ITS also provides a way to shift large amount of electricity from off peak time to peak time. Some gas turbine plants already use ITS to increase thermal efficiency during peak hours in summer. ITSs have also been widely used for building cooling to save energy cost. Among three cooling methods for LWR applications: once-through, wet cooling tower, and dry cooling tower, once-through cooling plants near a large water body like an ocean or a large lake and wet cooling plants can maintain the designed turbine backpressure (or condensation temperature) during 99% of the time; therefore, adding ITS to those plants will not generate large benefits. For once-through cooling plants near a limited water body like a river or a small lake, adding ITS can bring significant economic

  2. Analyses of fuel crud and coolant-borne corrosion products in normal water chemistry BWRs

    NASA Astrophysics Data System (ADS)

    Sawicki, Jerzy A.

    2011-12-01

    The samples of crud removed from the surface of fuel rods and corrosion products sampled by filtration of condensate and feed water in three boiling water reactors (BWR) operating at normal water chemistry (NWC) were analyzed using 57Fe Mössbauer spectroscopy. The corrosion products concentration and phase composition was examined in filter membranes exposed to influent and effluent of condensate polishing resin beds, as well as to final feed water. The brushed and scraped portions of fuel crud extracted from fuel rods during refueling outage comprised mostly hematite, α-Fe 2O 3, and submicron-sized goethite particles, α-FeOOH, in weight ratio similar to that observed in feed water. The observed phases are consistent with the oxidizing water chemistry of NWC BWRs. The feasibility of identifying other iron oxides and oxyhydroxides, as well as copper and zinc bearing phases in corrosion products from BWRs is briefly discussed. The results of this work can be used to better understand and minimize iron transport and crud deposition on fuel rods in BWRs.

  3. Correction of ground-water chemistry and carbon isotopic composition for effects of CO2 outgassing

    USGS Publications Warehouse

    Pearson, F.J.; Fisher, D.W.; Plummer, L.N.

    1978-01-01

    Direct Pco2 measurements on water samples from several CO2-charged warm springs are significantly higher than Pco2 values calculated from field pH and alkalinity (and other constituents). In addition, calcite saturation indices calculated from field pH and solution composition indicated supersaturation in samples which, on the basis of hydrogeologic concepts, should be near saturation or undersaturated. We attribute these discrepancies to uncertainties in field pH, resulting from CO2 outgassing during pH measurement. Because samples for direct Pco2 measurement can be taken with minimal disturbance to the water chemistry, we have used the measured Pco2 to back calculate an estimate of the field pH and the carbon isotopic composition of the water before outgassing. By reconstructing water chemistry in this way, we find generally consistent grouping of ??13C, pH, and degree of calcite saturation in samples taken from the same source at different times, an observation which we expect based on our understanding of the hydrogeology and geochemistry of the ground-water systems. This suggests that for very careful geochemical work, particularly on ground-waters much above ambient temperature, Pco2 measurements may provide more information on the system and a better estimate of its state of saturation with respect to carbonate minerals than can field measurements of pH. ?? 1978.

  4. Effects of iron on arsenic speciation and redox chemistry in acid mine water

    USGS Publications Warehouse

    Bednar, A.J.; Garbarino, J.R.; Ranville, J.F.; Wildeman, T.R.

    2005-01-01

    Concern about arsenic is increasing throughout the world, including areas of the United States. Elevated levels of arsenic above current drinking-water regulations in ground and surface water can be the result of purely natural phenomena, but often are due to anthropogenic activities, such as mining and agriculture. The current study correlates arsenic speciation in acid mine drainage and mining-influenced water with the important water-chemistry properties Eh, pH, and iron(III) concentration. The results show that arsenic speciation is generally in equilibrium with iron chemistry in low pH AMD, which is often not the case in other natural-water matrices. High pH mine waters and groundwater do not always hold to the redox predictions as well as low pH AMD samples. The oxidation and precipitation of oxyhydroxides deplete iron from some systems, and also affect arsenite and arsenate concentrations through sorption processes. ?? 2004 Elsevier B.V. All rights reserved.

  5. The influence of supraglacial debris on proglacial runoff fluctuations and water chemistry

    NASA Astrophysics Data System (ADS)

    Fyffe, Catriona; Brock, Ben; Kirkbride, Martin; Black, Andrew; Smiraglia, Claudio; Diolaiuti, Guglielmina

    2016-04-01

    This paper seeks to explore how the debris' influence on glacial ablation, topography and drainage structure impacts on the water chemistry and runoff signal of the proglacial stream. This was achieved through analysis of the supraglacial and proglacial water chemistry and the proglacial hydrograph of Miage Glacier, Western Italian Alps. Although the supraglacial water chemistry was influenced by the debris, there was also evidence that the less efficient hydrological system beneath the debris-covered lower tongue also increased the ion concentration of the proglacial stream. Compared to published data for clean glaciers, fewer diurnally classified daily hydrographs were found in the proglacial discharge record, with the amplitude of the diurnal signal peaking later and being relatively low in amplitude. These hydrograph characteristics were thought due to the debris' attenuation of the melt signal, and the smaller input streams and less efficient subglacial drainage system beneath the debris-covered lower tongue. Warmer than average weather conditions were required for strongly diurnal hydrographs to be shown, with a 'saw-toothed' hydrograph shown under average conditions. The diurnal relationship between conductivity and discharge often demonstrated anti-clockwise hysteresis, indicating that the more rapidly routed dilute melt component from the mid-glacier peaked before the peak in discharge. Components from higher up glacier and the lower debris-covered tongue likely had longer transit times and reached the proglacial stream later.

  6. Organic peroxide and OH formation in aerosol and cloud water: laboratory evidence for this aqueous chemistry

    NASA Astrophysics Data System (ADS)

    Lim, Y. B.; Turpin, B. J.

    2015-06-01

    Aqueous chemistry in atmospheric waters (e.g., cloud droplets or wet aerosols) is well accepted as an atmospheric pathway to produce secondary organic aerosol (SOAaq). Water-soluble organic compounds with small carbon numbers (C2-C3) are precursors for SOAaq and products include organic acids, organic sulfates, and high molecular weight compounds/oligomers. Fenton reactions and the uptake of gas-phase OH radicals are considered to be the major oxidant sources for aqueous organic chemistry. However, the sources and availability of oxidants in atmospheric waters are not well understood. The degree to which OH is produced in the aqueous phase affects the balance of radical and non-radical aqueous chemistry, the properties of the resulting aerosol, and likely its atmospheric behavior. This paper demonstrates organic peroxide formation during aqueous photooxidation of methylglyoxal using ultra high resolution Fourier Transform Ion Cyclotron Resonance electrospray ionization mass spectrometry (FTICR-MS). Organic peroxides are known to form through gas-phase oxidation of volatile organic compounds. They contribute secondary organic aerosol (SOA) formation directly by forming peroxyhemiacetals, and epoxides, and indirectly by enhancing gas-phase oxidation through OH recycling. We provide simulation results of organic peroxide/peroxyhemiacetal formation in clouds and wet aerosols and discuss organic peroxides as a source of condensed-phase OH radicals and as a contributor to aqueous SOA.

  7. Wildfires and water chemistry: effect of metals associated with wood ash.

    PubMed

    Cerrato, José M; Blake, Johanna M; Hirani, Chris; Clark, Alexander L; Ali, Abdul-Mehdi S; Artyushkova, Kateryna; Peterson, Eric; Bixby, Rebecca J

    2016-08-10

    The reactivity of metals associated with ash from wood collected from the Valles Caldera National Preserve, Jemez Mountains, New Mexico, was assessed through a series of laboratory experiments. Microscopy, spectroscopy, diffraction, and aqueous chemistry measurements were integrated to determine the chemical composition of wood ash and its effect on water chemistry. Climate change has caused dramatic impacts and stresses that have resulted in large-scale increases in wildfire activity in semi-arid areas of the world. Metals and other constituents associated with wildfire ash can be transported by storm event runoff and negatively affect the water quality in streams and rivers. Differences among ash from six tree species based on total concentrations of metals such as Ca, Al, Mg, Fe, and Mn were identified using non-metric multidimensional analysis. Metal-bearing carbonate and oxide phases were quantified by X-ray diffraction analyses and X-ray spectroscopy analyses. These metal-bearing carbonate phases were readily dissolved in the first 30 minutes of reaction with 18 MΩ water and 10 mM HCO3(-) in laboratory batch experiments which resulted in the release of metals and carbonates in the ash, causing water alkalinity to increase. However, metal concentrations decreased over the course of the experiment, suggesting that metals re-adsorb to ash. Our results suggest that the dissolution of metal-bearing carbonate and oxide phases in ash and metal re-adsorption to ash are relevant processes affecting water chemistry after wildfire events. These results have important implications to better understand the impact of wildfire events on water quality.

  8. Coagulation removal of humic acid-stabilized carbon nanotubes from water by PACl: influences of hydraulic condition and water chemistry.

    PubMed

    Ma, Si; Liu, Changli; Yang, Kun; Lin, Daohui

    2012-11-15

    Discharged carbon nanotubes (CNTs) can adsorb the widely-distributed humic acid (HA) in aquatic environments and thus be stabilized. HA-stabilized CNTs can find their way into and challenge the potable water treatment system. This study investigated the efficiency of coagulation and sedimentation techniques in the removal of the HA-stabilized multi-walled carbon nanotubes (MWCNTs) using polyaluminum chloride (PACl) as a coagulant, with a focus on the effects of hydraulic conditions and water chemistry. Stirring speeds in the mixing and reacting stages were gradually changed to examine the effect of the hydraulic conditions on the removal rate. The stirring speed in the reacting stage affected floc formation and thereby had a greater impact on the removal rate than the stirring speed in the mixing stage. Water chemistry factors such as pH and ionic strength had a significant effect on the stability of MWCNT suspension and the removal efficiency. Low pH (4-7) was favorable for saving the coagulant and maintaining high removal efficiency. High ionic strength facilitated the destabilization of the HA-stabilized MWCNTs and thereby lowered the required PACl dosage for the coagulation. However, excessively high ionic strength (higher than the critical coagulation concentration) decreased the maximum removal rate, probably by inhibiting ionic activity of PACl hydrolyzate in water. These results are expected to shed light on the potential improvement of coagulation removal of aqueous stabilized MWCNTs in water treatment systems.

  9. Understanding the Role of Water on Electron-Initiated Processes and Radical Chemistry

    SciTech Connect

    Garrett, Bruce C; Colson, Steven D; Dixon, David A.; Laufer, Allan H; Ray, Douglas

    2003-06-10

    On September 26–28, 2002, a workshop entitled “Understanding the Role of Water on Electron-Initiated Processes and Radical Chemistry” was held to assess new research opportunities in electron-driven processes and radical chemistry in aqueous systems. Of particular interest was the unique and complex role that the structure of water plays in influencing these processes. Novel experimental and theoretical approaches to solving long-standing problems in the field were explored. A broad selection of participants from universities and the national laboratories contributed to the workshop, which included scientific and technical presentations and parallel sessions for discussions and report writing.

  10. INLAND DISSOLVED SALT CHEMISTRY: STATISTICAL EVALUATION OF BIVARIATE AND TERNARY DIAGRAM MODELS FOR SURFACE AND SUBSURFACE WATERS

    EPA Science Inventory

    We compared the use of ternary and bivariate diagrams to distinguish the effects of atmospheric precipitation, rock weathering, and evaporation on inland surface and subsurface water chemistry. The three processes could not be statistically differentiated using bivariate models e...

  11. INLAND DISSOLVED SALT CHEMISTRY: STATISTICAL EVALUATION OF BIVARIATE AND TERNARY DIAGRAM MODELS FOR SURFACE AND SUBSURFACE WATERS

    EPA Science Inventory

    We compared the use of ternary and bivariate diagrams to distinguish the effects of atmospheric precipitation, rock weathering, and evaporation on inland surface and subsurface water chemistry. The three processes could not be statistically differentiated using bivariate models e...

  12. Evolution of water chemistry during Marcellus Shale gas development: A case study in West Virginia.

    PubMed

    Ziemkiewicz, Paul F; Thomas He, Y

    2015-09-01

    Hydraulic fracturing (HF) has been used with horizontal drilling to extract gas and natural gas liquids from source rock such as the Marcellus Shale in the Appalachian Basin. Horizontal drilling and HF generates large volumes of waste water known as flowback. While inorganic ion chemistry has been well characterized, and the general increase in concentration through the flowback is widely recognized, the literature contains little information relative to organic compounds and radionuclides. This study examined the chemical evolution of liquid process and waste streams (including makeup water, HF fluids, and flowback) in four Marcellus Shale gas well sites in north central West Virginia. Concentrations of organic and inorganic constituents and radioactive isotopes were measured to determine changes in waste water chemistry during shale gas development. We found that additives used in fracturing fluid may contribute to some of the constituents (e.g., Fe) found in flowback, but they appear to play a minor role. Time sequence samples collected during flowback indicated increasing concentrations of organic, inorganic and radioactive constituents. Nearly all constituents were found in much higher concentrations in flowback water than in injected HF fluids suggesting that the bulk of constituents originate in the Marcellus Shale formation rather than in the formulation of the injected HF fluids. Liquid wastes such as flowback and produced water, are largely recycled for subsequent fracturing operations. These practices limit environmental exposure to flowback. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Hydrogeology and water chemistry of Infranz catchment springs, Bahir Dar Area, Lake Tana Basin, Ethiopia

    NASA Astrophysics Data System (ADS)

    Abera, F. N.; Vancamp, M.; Walraevens, K.

    2016-12-01

    ABSTRACT The major springs in the Infranz catchment are a significant source of water for Bahir city and nearby villages, while they help to sustain Infranz River and the downstream wetlands. The aim of the research was to understand the hydrogeological conditions of these high-discharge springs, and to explain the hydrochemical composition of spring waters. Water samples from rainwater and springs were collected and analyzed and compared for major cations and anions. The hydrochemical data analysis showed that all water samples of the springs have freshwater chemistry, Ca-HCO3 type, while deep groundwater shows more evolved types. This indicates limited water-rock interaction and short residence time for the spring waters. The rise of NO3- and PO43- may indicate future water quality degradation unless the anthropogenic activities upgradient and nearby are restricted. The uptake of 75% of spring water for water supply of Bahir Dar results in wetland degradation. Key words: Spring water, Infranz River, Bahir Dar, Ethiopia, hydrochemistry

  14. Mineralogical and Anthropogenic Controls of Stream Water Chemistry in Salted Watersheds

    NASA Astrophysics Data System (ADS)

    Sun, H.; Alexander, J.; Gove, B.; Chakowski, N.; Husch, J.

    2013-12-01

    Analyses of major cation and anion concentrations in stream water and soil solutions from two salted (regular applications of winter road deicing salt) watersheds located in the northeastern United States indicate that both mineralogical and anthropogenic factors are important in controlling water chemistry. The relatively stable concentrations of calcium and magnesium, as well as their possible weathering paths identified by mass-balance models, indicate that the weathering of feldspars and the dissolution of carbonates are the primary sources for these two cations in the small, salted Centennial Lake Watershed (CLW, 1.95 km 2). However, the relatively stable and lower concentrations of sodium and chloride in soil solutions, and their fluctuating and higher concentrations in stream water from the CLW, indicate that road deicing salt is the primary source for these ions in stream water. Furthermore, positive correlations between calcium and sulfur concentrations and magnesium and sulfur concentrations in soil solutions, as well as positive correlations between sulfur and iron concentrations in soil compositions, indicate that both the dissolution of gypsum and the oxidation of pyrite into hematite are the primary sources of sulfate in the CLW. Analyses of water chemistry from the related and much larger Delaware River Watershed (DRW, 17560 km 2) show that sodium and chloride concentrations have increased steadily due to the regular application of winter deicing salt over the 68 years for which data are available. The more rapid increase of stream water chloride concentrations, relative to the increase in sodium, also results in the steady decline of Na+/Cl-molar ratios in the DRW over that time. In addition, the reduction of sulfate and increase of bicarbonate concentration since 1980 in DRW stream water may be attributed to the decline of sulfate levels in atmospheric deposition resulting from enhanced national and state environmental regulations and a shift in

  15. Hydrology and pore water chemistry in a permafrost wetland, Ilulissat, Greenland

    NASA Astrophysics Data System (ADS)

    Jessen, Søren; Holmslykke, Hanne D.; Rasmussen, Kristine; Richardt, Niels; Holm, Peter E.

    2014-06-01

    Hydrological and geochemical processes controlling the pore water chemistry in a permafrost wetland, with loam overlain by sphagnum peat, were investigated. The vertical distributions of dissolved Cl, and of pore water δ18O, appeared unrelated to ion freeze-out and isotope ice-water fractionation processes, respectively, dismissing solute freeze-out as a main control on the water chemistry. However, concentrations of major ions, others than Cl, generally increased with depth into the active layer. A conceptual model for water and solute movement in the active layer was derived. The model indicates upward diffusive transport of elements, released in the loam layer by mineral weathering, to the peat layer, in which lateral advective transport dominates. Active layer pore water and water of melted core sections of permafrost were of Ca-Mg-HCO3 type (1:1:4 stoichiometry) and were subsaturated for calcite and dolomite. The results are consistent with an annual cycling of inorganic carbon species, Ca and Mg, via cryogenic carbonate precipitation during fall freeze-up and their redissolution following spring thaw. Similarly, elevated Fe2+ concentrations appear to be related to cryogenic siderite formation. Pore water in the active layer showed high partial pressures of CO2, indicating the feasibility of bubble ebullition as a greenhouse gas emission pathway from permafrost wetlands. Elevated concentrations of geogenic trace elements (Ni, Al, and As) were observed, and the controlling geochemical processes are discussed. The conceptual model for water and solute movement was applied to quantify the contribution of released trace elements to a downstream lake in the permafrost catchment.

  16. Platoon Interactions and Real-World Traffic Simulation and Validation Based on the LWR-IM

    PubMed Central

    Ng, Kok Mun; Reaz, Mamun Bin Ibne

    2016-01-01

    Platoon based traffic flow models form the underlying theoretical framework in traffic simulation tools. They are essentially important in facilitating efficient performance calculation and evaluation in urban traffic networks. For this purpose, a new platoon-based macroscopic model called the LWR-IM has been developed in [1]. Preliminary analytical validation conducted previously has proven the feasibility of the model. In this paper, the LWR-IM is further enhanced with algorithms that describe platoon interactions in urban arterials. The LWR-IM and the proposed platoon interaction algorithms are implemented in the real-world class I and class II urban arterials. Another purpose of the work is to perform quantitative validation to investigate the validity and ability of the LWR-IM and its underlying algorithms to describe platoon interactions and simulate performance indices that closely resemble the real traffic situations. The quantitative validation of the LWR-IM is achieved by performing a two-sampled t-test on queues simulated by the LWR-IM and real queues observed at these real-world locations. The results reveal insignificant differences of simulated queues with real queues where the p-values produced concluded that the null hypothesis cannot be rejected. Thus, the quantitative validation further proved the validity of the LWR-IM and the embedded platoon interactions algorithm for the intended purpose. PMID:26731745

  17. Platoon Interactions and Real-World Traffic Simulation and Validation Based on the LWR-IM.

    PubMed

    Ng, Kok Mun; Reaz, Mamun Bin Ibne

    2016-01-01

    Platoon based traffic flow models form the underlying theoretical framework in traffic simulation tools. They are essentially important in facilitating efficient performance calculation and evaluation in urban traffic networks. For this purpose, a new platoon-based macroscopic model called the LWR-IM has been developed in [1]. Preliminary analytical validation conducted previously has proven the feasibility of the model. In this paper, the LWR-IM is further enhanced with algorithms that describe platoon interactions in urban arterials. The LWR-IM and the proposed platoon interaction algorithms are implemented in the real-world class I and class II urban arterials. Another purpose of the work is to perform quantitative validation to investigate the validity and ability of the LWR-IM and its underlying algorithms to describe platoon interactions and simulate performance indices that closely resemble the real traffic situations. The quantitative validation of the LWR-IM is achieved by performing a two-sampled t-test on queues simulated by the LWR-IM and real queues observed at these real-world locations. The results reveal insignificant differences of simulated queues with real queues where the p-values produced concluded that the null hypothesis cannot be rejected. Thus, the quantitative validation further proved the validity of the LWR-IM and the embedded platoon interactions algorithm for the intended purpose.

  18. Chemistry of Water Collected From an Unventillated Drift, Yucca Mountain, Nevada

    SciTech Connect

    B.D. Marshall; T.A. Oliver; Z.E. Peterman

    2006-06-20

    The chemical composition of water that may be present in the emplacement drifts is a key issue for the isolation of high-level radioactive waste in a proposed mined geologic repository at Yucca Mountain, Nevada. Chemical constituents in water that may contact waste containers may affect rates of corrosion of the container materials. Long-term simulations of the in-drift chemical environment rely on ambient water chemistry, heat perturbations, and the interaction of ambient water with the engineered barriers (e.g. waste containers) and other introduced materials (e.g. rock bolts). In an attempt to induce seepage in the Enhanced Characterization of the Repository Block Cross Drift, bulkheads were constructed to isolate part of the 2.7-km-long drift from active ventilation. The bulkheads were closed and active ventilation ceased for periods up.to 454 days. After opening the bulkheads, water was observed in small puddles on plastic sheets and on rubber conveyor belt surfaces; droplets of water were observed on many surfaces of various construction-related introduced materials. Mold or fungal colonies also were present. The puddles of water were sampled seven times from January 2003 to June 2005; most samples appeared yellow to brown. The water samples were analyzed for major and trace constituents by using ion chromatography and inductively-coupled plasma mass spectrometry. Total dissolved solids (TDS) in the puddle-water samples ranged from 195 to 22,000 milligrams per liter (mg/L) and pH ranged from 4.2 to 8.9; these values are different from ambient pore-water samples extracted from adjacent rock (TDS < 1,400 mg/L and pH from 6.7 to 8.2). The chemical composition of the puddle-water samples is dominated by sodium and chloride, also different from the pore-water samples, which are dominated by sodium, calcium, and bicarbonate. Zinc concentrations ranged from 0.5 to 3,100 mg/L, substantially greater than the less than 0.1 mg/L values measured in pore water. Some of

  19. Analysis of Water-Quality Trends for Selected Streams in the Water Chemistry Monitoring Program, Michigan, 1998-2005

    USGS Publications Warehouse

    Hoard, C.J.; Fuller, Lori M.; Fogarty, Lisa R.

    2009-01-01

    In 1998, the Michigan Department of Environmental Quality and the U.S. Geological Survey began a long-term monitoring program to evaluate the water quality of most watersheds in Michigan. Major goals of this Water-Chemistry Monitoring Program were to identify streams exceeding or not meeting State or Federal water-quality standards and to assess if constituent concentrations reflecting water quality in these streams were increasing or decreasing over time. As part of this program, water-quality data collected from 1998 to 2005 were analyzed to identify potential trends. Sixteen water-quality constituents were analyzed at 31 sites across Michigan, 28 of which had sufficient data to analyze for trends. Trend analysis on the various water-quality data was done using the uncensored Seasonal Kendall test within the computer program ESTREND. The most prevalent trend detected throughout the state was for chloride. Chloride trends were detected at 8 of the 28 sites; trends at 7 sites were increasing and the trend at 1 site was decreasing. Although no trends were detected for various nitrogen species or phosphorus, these constituents were detected at levels greater than the U.S. Environmental Protection Agency recommendations for nutrients in water. The results of the trend analysis will help to establish a baseline to evaluate future changes in water quality in Michigan streams.

  20. Seasonal variation of water level, water and soil temperature, chemistry, and stable isotopes in hyporheic zone of Korea

    NASA Astrophysics Data System (ADS)

    Jeon, W. H.; Lee, J. Y.

    2015-12-01

    The purpose of study was to evaluate interaction between groundwater and stream water in hyporheic zone using water level, water temperature, soil temperature, chemistry, and stable isotopes. We installed seven piezometers (IYHW1 to 7) in the streambed that across stream in every 10 m and in depth of 0.85 to 1.54 m, a device that measure stage level nearby IYHW1, and devices that measure soil temperature in every 10 cm down to 50 cm nearby each piezometer was installed. We monitored water level and water temperature every hour from automatic transducers at the piezometers and the stage level, and soil temperatures were monitored every two hours. We took samples from the hyporheic water, stream water, and nearby groundwater to analysis chemical and isotopic compositions. The water level difference between stream water and hyporheic waters indicated that groundwater was downwelling in wet season and upwelling in dry season. The groundwater temperature remained steady in different seasons, but the stream water represented a frequent fluctuation with large amplitude. The hyporheic waters and soil temperature represented intermediate variation characteristics. The chemical compositions were not able to indicate in interaction of groundwater and stream water because no distinctive difference in seasonal variation in waters. The quantity of isotopic compositions of oxygen and hydrogen determined from using mixing ratio indicated that downwelling in wet season and upwelling in dry season. This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2011-0007232).

  1. Photochemical Formation of Aerosol in Planetary Atmospheres: Photon and Water Mediated Chemistry of SO_2

    NASA Astrophysics Data System (ADS)

    Kroll, Jay A.; Donaldson, D. J.; Vaida, Veronica

    2016-06-01

    Sulfur compounds have been observed in a number of planetary atmospheres throughout our solar system. Our current understanding of sulfur chemistry explains much of what we observe in Earth's atmosphere. However, several discrepancies between modeling and observations of the Venusian atmosphere show there are still problems in our fundamental understanding of sulfur chemistry. This is of particular concern due to the important role sulfur compounds play in the formation of aerosols, which have a direct impact on planetary climates, including Earth's. We investigate the role of water complexes in the hydration of sulfur oxides and dehydration of sulfur acids and will present spectroscopic studies to document such effects. I will present recent work investigating mixtures of SO_2 and water that generate large quantities of aerosol when irradiated with solar UV light, even in the absence of traditional OH chemistry. I will discuss a proposed mechanism for the formation of sulfurous acid (H_2SO_3) and present recent experimental work that supports this proposed mechanism. Additionally, the implications that photon-induced hydration of SO_2 has for aerosol formation in the atmosphere of earth as well as other planetary atmospheres will be discussed.

  2. Lagrangian transport of water vapor and CFCs in a coupled Chemistry Climate Model

    NASA Astrophysics Data System (ADS)

    Hoppe, Charlotte; Müller, Rolf; Hoffmann, Lars; Konopka, Paul; Plöger, Felix; Grooß, Jens-Uwe

    2013-04-01

    We describe the implementation of a Lagrangian transport core in a chemistry climate model (CCM). Thereby we address the common problem of properly representing trace gas distributions in a classical Eulerian framework with a fixed model grid, particularly in regions with strong trace gas gradients. A prominent example is stratospheric water vapor, which is an important driver of surface climate change on decadal scales. In this case, the transport representation is particularly important in the tropical tropopause layer (TTL), where tropospheric air enters into the stratosphere. We have coupled the Chemical Lagrangian Model of the Stratosphere (CLaMS) with the ECHAM-MESSy Atmospheric Chemistry Model (EMAC). The latter includes the ECHAM5 climate model, and the MESSy interface, which allows for flexible coupling and switching between different submodels. The chemistry transport model CLaMS provides a fully Lagrangian transport representation to calculate constituent transport for an ensemble of air parcels that move along trajectories. To facilitate the calculation of long time-series a simplified chemistry scheme was implemented. Various studies show that the CLaMS model is particularly suited to properly represent dynamics and chemistry in the UT/LS region. The analysis of mean age of stratospheric air gives insight into the different transport characteristics of the Eulerian and the Lagrangian transport schemes. Mean age of air, calculated in both frameworks, is compared regarding the representation of important processes, i.e. descent in the polar vortex, upwelling in the tropical pipe, and isentropic in-mixing in subtropical regions. We also compared the zonal mean distributions and photochemical lifetimes of CFC-11 and CFC-12 with climatologies from different satellite experiments (ACE-FTS, HIRDLS, and MIPAS). CLaMS stratospheric water vapor distributions show remarkable differences compared to the stratospheric water vapor simulated by ECHAM, especially in

  3. Geohydrology and water chemistry in the Rialto-Colton Basin, San Bernardino County, California

    USGS Publications Warehouse

    Woolfenden, Linda R.; Kadhim, Dina

    1997-01-01

    The 40-square-mile Rialto-Colton ground- water basin is in western San Bernardino County, California, about 60 miles east of Los Angeles.This basin was chosen for storage of imported water because of the good quality of native ground water, the known capacity for additional ground-water storage in the basin, and the availability of imported water. Because the movement and mixing of imported water needed to be determined, the San Bernardino Valley Municipal Water District entered into a cooperative program with the U.S.Geological Survey in 1991 to study the geohydrology and water chemistry in the Rialto- Colton basin. Ground-water flow and chemistry were investigated using existing data, borehole- geophysical and lithologic logs from newly drilled test holes, measurement of water levels, and chemical analyses of water samples. The Rialto-Colton basin is bounded on the northwest and southeast by the San Gabriel Mountains and the Badlands, respectively. The San Jacinto Fault and Barrier E form the northeastern boundary, and the Rialto-Colton Fault forms the southwestern boundary. Except in the southeastern part of the basin, the San Jacinto and Rialto-Colton Faults act as groundwater barriers that impede ground- water flow into and out of the basin.Barrier E generally does not impede ground- water flow into the basin. The ground-water system consists primarily of gravel, sand, silt, and clay. The maximum thickness is greater than 1,000 feet. The ground- water system is divided into four water-bearing units: river-channel deposits, and upper, middle, and lower water-bearing units. Relatively impermeable consolidated deposits underlie the lower water- bearing unit and form the lower boundary of the ground- water system. Ground water moves from east to west in the river-channel deposits and upper water-bearing unit in the southeastern part of the basin, and from northwest to southeast in the middle and lower water-bearing units. Two major internal faults, Barrier J and

  4. Chemistry and age of ground water in the southwestern Hueco Bolson, New Mexico and Texas

    USGS Publications Warehouse

    Anderholm, Scott K.; Heywood, Charles E.

    2003-01-01

    This report, prepared in cooperation with El Paso Water Utilities, presents the results of an investigation to determine the chemistry and age of ground water on the southwestern side of the Hueco Bolson. The radioactive isotope carbon-14 was used to estimate the length of time that water from wells has been isolated from the atmosphere, which is the modern carbon-14 reservoir. Nine wells on the southwestern side of the Hueco Bolson were sampled for analysis of common constituents, nutrients, total organic carbon, trace elements, stable isotopes, and radioactive isotopes. Dissolved-solids concentrations in water from the wells sampled ranged from 269 to 2,630 milligrams per liter. Sodium concentrations generally increased linearly with chloride concentrations, possibly indicating mixing of dilute recharge water with sodium chloride brine. Concentrations of nutrients and trace elements generally were small. The deuterium and oxygen-18 composition in all samples except those from wells adjacent to the Rio Grande indicates that infiltration of precipitation is the main source of water to these wells and that evaporation has not affected the isotopic composition of the water. The source of water from wells adjacent to the Rio Grande is probably not the same source as the water from wells adjacent to the Franklin Mountains. The calculated apparent carbon- 14 ages ranged from 12,100 to 25,500 years.

  5. Characteristics Data Base: Programmer's guide to the LWR Quantities Data Base

    SciTech Connect

    Jones, K.E. ); Moore, R.S. )

    1990-08-01

    The LWR Quantities Data Base is a menu-driven PC data base developed as part of OCRWM's waste, technical data base on the characteristics of potential repository wastes, which also includes non-LWR spent fuel, high-level and other materials. This programmer's guide completes the documentation for the LWR Quantities Data Base, the user's guide having been published previously. The PC data base itself may be requested from the Oak Ridge National Laboratory, using the order form provided in Volume 1 of publication DOE/RW-0184.

  6. Role of water in alkali halide heterogeneous chemistry relevant to the atmosphere: A surface science study

    NASA Astrophysics Data System (ADS)

    Ghosal, Sutapa

    2001-05-01

    Water is a ubiquitous atmospheric constituent. The interaction of water in its various forms (vapor, liquid, ice) with other atmospheric constituents has a significant impact on the chemistry of the atmosphere. Another class of compounds that are of considerable importance in atmospheric chemistry are alkali halide salts such as sea salt particles. Heterogeneous reactions of alkali halides with gas phase pollutants are believed to be an important source of halogens in the troposphere. There is an increasing amount of evidence that the presence of water plays an important role in the heterogeneous chemistry of alkali halide particles. It is the goal of this dissertation to contribute to the understanding of the interaction of water with alkali halide surfaces and its atmospheric implications. Surface processes are of fundamental importance in heterogeneous atmospheric chemistry, but they are often difficult to study because of their inherent complexity. As this dissertation shows, the use of modern surface science techniques offer valuable insights into these complex processes and as such offer complementary alternatives to the traditional atmospheric chemistry experiments. The surface science techniques used in this dissertation are X-ray photoelectron spectroscopy (XPS), scanning polarization force microscopy (SPFM) and scanning electron microscopy (SEM). Presented here are the results of the XPS and SEM studies undertaken to determine the nature and content of surface adsorbed water on NaCl as a function of surface defects. The details of HNO3 uptake on NaCl and the effect of surface adsorbed water on this uptake are also discussed. Our results show that the amount of ``strongly adsorbed water'' (SAW) on the surface of NaCl particles depends on the particle size and hence, on the concentration of surface defects. Unlike the (100) single crystal the more defective surfaces show dissociative water uptake at room temperature upon exposure to water vapor well below

  7. Short communication on "In-situ TEM ion irradiation investigations on U3Si2 at LWR temperatures"

    SciTech Connect

    Miao, Yinbin; Harp, Jason; Mo, Kun; Bhattacharya, Sumit; Baldo, Peter; Yacout, Abdellatif M.

    2016-11-21

    Here, the radiation-induced amorphization of U3Si2 was investigated by in-situ transmission electron microscopy using 1 MeV Kr ion irradiation. Both arc-melted and sintered U3Si2 specimens were irradiated at room temperature to confirm the similarity in their responses to radiation. The sintered specimens were then irradiated at 350 °C and 550 °C up to 7.2 × 1015 ions/cm2 to examine their amorphization behavior under light water reactor (LWR) conditions. U3Si2 remains crystalline under irradiation at LWR temperatures. Oxidation of the material was observed at high irradiation doses.

  8. Uncertainties in water chemistry in disks: An application to TW Hydrae

    NASA Astrophysics Data System (ADS)

    Kamp, I.; Thi, W.-F.; Meeus, G.; Woitke, P.; Pinte, C.; Meijerink, R.; Spaans, M.; Pascucci, I.; Aresu, G.; Dent, W. R. F.

    2013-11-01

    Context. This paper discusses the sensitivity of water lines to chemical processes and radiative transfer for the protoplanetary disk around TW Hya. The study focuses on the Herschel spectral range in the context of new line detections with the PACS instrument from the Gas in Protoplanetary Systems project (GASPS). Aims: The paper presents an overview of the chemistry in the main water reservoirs in the disk around TW Hya. It discusses the limitations in the interpretation of observed water line fluxes. Methods: We use a previously published thermo-chemical Protoplanetary Disk Model (ProDiMo) of the disk around TW Hya and study a range of chemical modeling uncertainties: metallicity, C/O ratio, and reaction pathways and rates leading to the formation of water. We provide results for the simplified assumption of Tgas = Tdust to quantify uncertainties arising for the complex heating/cooling processes of the gas and elaborate on limitations due to water line radiative transfer. Results: We report new line detections of p-H2O (322-211) at 89.99 μm and CO J = 18-17 at 144.78 μm for the disk around TW Hya. Disk modeling shows that the far-IR fine structure lines ([O i], [C ii]) and molecular submm lines are very robust to uncertainties in the chemistry, while the water line fluxes can change by factors of a few. The water lines are optically thick, sub-thermally excited and can couple to the background continuum radiation field. The low-excitation water lines are also sensitive to uncertainties in the collision rates, e.g. with neutral hydrogen. The gas temperature plays an important role for the [O i] fine structure line fluxes, the water line fluxes originating from the inner disk as well as the high excitation CO, CH+ and OH lines. Conclusions: Due to their sensitivity on chemical input data and radiative transfer, water lines have to be used cautiously for understanding details of the disk structure. Water lines covering a wide range of excitation energies provide

  9. Reactive nitrogen chemistry in aerosol water as a source of sulfate during haze events in China

    NASA Astrophysics Data System (ADS)

    Cheng, Yafang; Zheng, Guangjie; Wei, Chao; Mu, Qing; Zheng, Bo; Wang, Zhibin; Gao, Meng; Zhang, Qiang; Wang, Kebin; Carmichael, Gregory; Pöschl, Ulrich; Su, Hang

    2017-04-01

    Fine-particle pollution associated with winter haze threatens the health of more than 400 million people in the North China Plain. Sulfate is a major component of fine haze particles. Record sulfate concentrations of up to 300 μg m-3 were observed during the January 2013 winter haze event in Beijing. State-of-the-art air quality models that rely on sulfate production mechanisms requiring photochemical oxidants cannot predict these high levels because of the weak photochemistry activity during haze events. We find that the missing source of sulfate and particulate matter can be explained by reactive nitrogen chemistry in aerosol water. The aerosol water serves as a reactor, where the alkaline aerosol components trap SO2, which is oxidized by NO2 to form sulfate, whereby high reaction rates are sustained by the high neutralizing capacity of the atmosphere in northern China. This mechanism is self-amplifying because higher aerosol mass concentration corresponds to higher aerosol water content, leading to faster sulfate production and more severe haze pollution. Reference: Cheng, Y., Zheng, G., Wei, C., Mu, Q., Zheng, B., Wang, Z., Gao, M., Zhang, Q., He, K., Carmichael, G., Pöschl, U., and Su, H.: Reactive nitrogen chemistry in aerosol water as a source of sulfate during haze events in China, Science Advances, 2, 10.1126/sciadv.1601530, 2016.

  10. Short Term Variability in Water Column and Porewater Carbon Chemistry on a Tropical Reef

    NASA Astrophysics Data System (ADS)

    Drupp, P. S.; De Carlo, E. H.; Mackenzie, F. T.; Thompson, R.; Sabine, C. L.; Feely, R. A.

    2013-12-01

    A high-resolution carbon system study has been ongoing on the Kaneohe Bay barrier reef on the island of Oahu, Hawaii since 2008, in an effort to characterize short term variability of the carbon system in the water column and porewaters. In addition, during a 3 week time period from June 4th-24th, multiple sensors were deployed at the CRIMP-2 MAPCO2 buoy and discrete bottle samples were collected frequently, including once an hour for a period of 48 hours. In-situ sensors measured pCO2, pH, temperature and salinity at the CRIMP-2 location. Dissolved inorganic carbon to total alkalinity ratios indicate a reef system where primary production slightly exceeds calcification, consistent with previous studies on the reef. A second MAP-CO2 buoy located outside the bay (Kaneohe Buoy) also measured pCO2 and pH to serve as an end member point for water entering the reef system. Porewater has been collected at varying depths in order to determine the effect of overlying water conditions on the carbonic-acid system chemistry. Porewater alkalinity appears to vary with changes in overlying water column chemistry and physical forcings such as wind and current speeds, which influence flushing rates and ventilation, and calcium and magnesium data suggests dissolution of soluble magnesian calcites concurrently with precipitation of calcites.

  11. ORNL studies of fission product release under LWR accident conditions

    SciTech Connect

    Osborne, M.F.; Lorenz, R.A.; Collins, J.L.

    1991-01-01

    High burnup Zircaloy-clad UO{sub 2} fuel specimens have been heated to study the release of fission products in tests simulating LWR accident conditions. The dominant variable was found to be temperature, with atmosphere, time, and burnup also being significant variables. Comparison of data from tests in steam and hydrogen, at temperatures of 2000 to 2700 K, have shown that the releases of the most volatile species (Kr, Xe, I, and Cs) are relatively insensitive to atmosphere. The releases of the less-volatile species (Sr, Mo, Ru, Sb, Te, Ba, and Eu), however, may vary by orders of magnitude depending on atmosphere. In addition, the atmosphere may drastically affect the mode and extent of fuel destruction.

  12. Irradiation effects on thermal properties of LWR hydride fuel

    NASA Astrophysics Data System (ADS)

    Terrani, Kurt; Balooch, Mehdi; Carpenter, David; Kohse, Gordon; Keiser, Dennis; Meyer, Mitchell; Olander, Donald

    2017-04-01

    Three hydride mini-fuel rods were fabricated and irradiated at the MIT nuclear reactor with a maximum burnup of 0.31% FIMA or ∼5 MWd/kgU equivalent oxide fuel burnup. Fuel rods consisted of uranium-zirconium hydride (U (30 wt%)ZrH1.6) pellets clad inside a LWR Zircaloy-2 tubing. The gap between the fuel and the cladding was filled with lead-bismuth eutectic alloy to eliminate the gas gap and the large temperature drop across it. Each mini-fuel rod was instrumented with two thermocouples with tips that are axially located halfway through the fuel centerline and cladding surface. In-pile temperature measurements enabled calculation of thermal conductivity in this fuel as a function of temperature and burnup. In-pile thermal conductivity at the beginning of test agreed well with out-of-pile measurements on unirradiated fuel and decreased rapidly with burnup.

  13. Feasibility of performing criticality experiments with spent LWR fuel

    SciTech Connect

    Bierman, S.R.

    1988-02-01

    Criticality experiments can be performed with irradiated LWR fuel under very well defined and controlled conditions to provide data sutiable for verifying calculational models. Two facilities currently exist in which such experiments could be performed. Furthermore, the experiments can be performed in a timely manner and for a relatively reasonable cost. It is expected the cost will be greater than those normally incurred for similar experiments with unirradiated fuel because of the handling problems created by the high radiation fields. Although the cost will of course depend on the scoper of the experimental programs, current estimates indicate the costs will be less or comparable to a similar level of effort in other activities with irradiated fuel (e.g., Dry Rod Consolation Project). 2 figs.

  14. Monsoon Season Surface Water Chemistry Response Following Wildfire: 2003 Aspen Fire in Sabino Canyon, Arizona

    NASA Astrophysics Data System (ADS)

    Einloth, S. L.; Chief, K. D.; Ekwurzel, B.; Nijssen, B.; Ferré, P. A.

    2003-12-01

    The Aspen Fire in the Coronado National Forest north of Tucson burned in excess of 80,000 acres and destroyed more than 300 structures. Exposed, burned soils are highly vulnerable to intense monsoon rains, leading to increases in surface runoff, peak flows, and erosion rates. As part of an integrated investigation of the hydrologic impacts of this fire, we rapidly mobilized a field sampling campaign during the 2003 monsoon season that began immediately following the resolution of the fire. Stream water chemistry serves as an integrated signal of many watershed processes: precipitation, runoff, infiltration, soil hydrophobic layers, ash deposition in the stream, debris flows, and subsequent water/ash chemical equilibrium reactions. The portion of the watershed that has been burned by the Aspen fire covers a wide range of elevation and vegetation zones of the Santa Catalina Mountains. Many biogeochemical and hydrological processes within this area were altered by a sudden lack of vegetation and changes in soil properties following a fire: evapotranspiration, litter volume, organic decomposition, leaching, cation exchange, anion sorption, nutrient uptake, and soil hydrophobic layers. Surface water and precipitation samples were collected following an event-based sampling strategy, while soil samples were collected in each vegetation and burn severity regime. Precipitation samples were collected to characterize temperature and elevation effects on precipitation chemistry, in particular stable isotopes. The surface water chemistry changes measured throughout each hydrograph event can be linked to air permeameter results, a rapid measurement for soil hydraulic conductivity, for the different burn severity and vegetation zone regimes. Both nutrient and suspended sediment loads greatly increased following the fire. A debris flow mobilized large diameter boulders. Stream gauge flow event peaks were larger than expected given concurrent extensive precipitation gauge network

  15. Assessing Changes in Water Chemistry Along the Mountain to Urban Gradient

    NASA Astrophysics Data System (ADS)

    Gabor, R. S.; Brooks, P. D.; Neilson, B. T.; Barnes, M. L.; Stout, T.; Millington, M. R.; Gelderloos, A.; Tennant, H.; Eiriksson, D.

    2015-12-01

    Throughout the western US, growing population centers rely on mountain watersheds that are already sensitive to hydrologic stressors. We examined rivers along Utah's Wasatch Front over a range of spatial and discharge scales, confusing on the mountain-to-urban transition to identify how urbanization impacts water resources. The rivers we studied all originate in canyons with impact level ranging from minimal human disturbance to roads and open grazing cattle. Each river enters an urban area after leaving the canyon, where there is significantly more anthropogenic impact on the system. As part of an interdisciplinary effort with the iUTAH project, sample sites were selected at intervals along each river and a variety of measurements were made, including basic water chemistry along with discharge, water isotopes, nutrients, and organic matter analysis. By combining physical and chemical parameters we were able to quantify groundwater influence in gaining reaches and how those differ between the mountain and urban environments. We also identified how the urban system impacted hydrologic and biogeochemical processes in the catchment. For example, in Red Butte Creek discharge tripled through gaining reached in the canyon with only small corresponding changes in conductivity or nitrate levels. However in the urban stretch a gaining reach that tripled the discharge corresponded with a doubling in the conductivity and order of magnitude increase in nitrate. The fact that we first see this change in chemistry during a gaining reach, and not in an area full of storm culverts, suggests that urban impact to stream chemistry predominately occurs through the groundwater. Further work will incorporate ecological and climatic data along with the hydrologic and chemical datasets to identify how controls on water resources change along the mountain to urban gradient. By combining this physical information with sociological data we can identify green infrastructure solutions to

  16. The millennium water vapour drop in the stratosphere in chemistry-climate model simulations

    NASA Astrophysics Data System (ADS)

    Brinkop, Sabine; Dameris, Martin; Joeckel, Patrick; Garny, Hella; Lossow, Stefan; Stiller, Gabriele

    2015-04-01

    This study investigates the millennium water vapour drop, the abrupt and severe water vapour decline in the stratosphere beginning in year 2000, by means of various simulations using the Chemistry-Climate Model (CCM) EMAC. Since the beginning 1980s, balloon borne stratospheric water vapour measurements and corresponding satellite measurements starting in the early 1990s indicated a long-term steady increase of water vapour concentrations. However, the multi-year data sets also show significant fluctuations on different time scales. In the year 2000, an extraordinary sudden drop of stratospheric water vapour concentration has been observed followed by persistent low values for several years. Solomon et al. (2010) showed that this drop slowed down the rate of increase in global surface temperature over the following decade by about 25%. So far, the stratospheric water vapour variations observed by satellite from 1992 to 2012 are not reproduced by CCM simulations forced by observed changes in sea surface temperatures, greenhouse gases and ozone-depleting substances (Gettelman et al., 2010, Randel and Jensen, 2013). However, the CCM EMAC is able to reproduce the signature and pattern of the water vapour disturbances in agreement with those derived from observations. In this paper we present results of a hierarchy of simulations with the CCM EMAC, demonstrating that it is possible to retrace the observed water vapour fluctuations in the stratosphere (incl. the millennium drop), if suitable inner and outer boundary conditions are applied.

  17. Seasonal change in precipitation, snowpack, snowmelt, soil water and streamwater chemistry, northern Michigan

    USGS Publications Warehouse

    Stottlemyer, R.; Toczydlowski, D.

    1999-01-01

    We have studied weekly precipitation, snowpack, snowmelt, soil water and streamwater chemistry throughout winter for over a decade in a small (176 ha) northern Michigan watershed with high snowfall and vegetated by 60 to 80 year-old northern hardwoods. In this paper, we examine physical, chemical, and biological processes responsible for observed seasonal change in streamwater chemistry based upon intensive study during winter 1996-1997. The objective was to define the contributions made to winter and spring streamwater chemical concentration and flux by processes as snowmelt, over-winter forest floor and surface soil mineralization, immobilization, and exchange, and subsurface flowpath. The forest floor and soil were unfrozen beneath the snowpack which permitted most snowmelt to enter. Over-winter soil mineralization and other biological processes maintain shallow subsurface ion and dissolved organic carbon (DOC) reservoirs. Small, but steady, snowmelt throughout winter removed readily mobilized soil NO3- which resulted in high over-winter streamwater concentrations but little flux. Winter soil water levels and flowpaths were generally deep which increased soil water and streamwater base cation (C(B)), HCO3-, and Si concentrations. Spring snowmelt increased soil water levels and removal of ions and DOC from the biologically active forest floor and shallow soils. The snowpack solute content was a minor component in determining streamwater ion concentration or flux during and following peak snowmelt. Exchangeable ions, weakly adsorbed anions, and DOC in the forest floor and surface soils dominated the chemical concentration and flux in soil water and streamwater. Following peak snowmelt, soil microbial immobilization and rapidly increased plant uptake of limiting nutrients removed nearly all available nitrogen from soil water and streamwater. During the growing season high evapotranspiration increased subsurface flowpath depth which in turn removed weathering

  18. Mercury cycling in stream ecosystems. 1. Water column chemistry and transport

    USGS Publications Warehouse

    Brigham, M.E.; Wentz, D.A.; Aiken, G.R.; Krabbenhoft, D.P.

    2009-01-01

    We studied total mercury (THg) and methylmercury (MeHg) in eight streams, located in Oregon, Wisconsin, and Florida, that span large ranges in climate, landscape characteristics, atmospheric Hg deposition, and water chemistry. While atmospheric deposition was the source of Hg at each site, basin characteristics appeared to mediate this source by providing controls on methylation and fluvial THg and MeHg transport. Instantaneous concentrations of filtered total mercury (FTHg) and filtered methylmercury (FMeHg) exhibited strong positive correlations with both dissolved organic carbon (DOC) concentrations and streamflow for most streams, whereas mean FTHg and FMeHg concentrations were correlated with wetland density of the basins. For all streams combined, whole water concentrations (sum of filtered and particulate forms) of THg and MeHg correlated strongly with DOC and suspended sediment concentrations in the water column. ?? 2009 American Chemical Society.

  19. Can sediment data be used to predict alkalinity and base cation chemistry of surface waters?

    PubMed

    Begum, S; McClean, C J; Cresser, M S; Breward, N

    2010-12-15

    We hypothesise that stream sediment elemental composition can predict mean and minimum concentrations of alkalinity, Ca and Mg in the river water throughout a river network. We tested this hypothesis for the River Derwent catchment in North Yorkshire, England, by using 6 years of water chemistry data from the Environment Agency and a digital elevation model to flow path-weight British Geological Survey (BGS) sediment element concentration data. The predictive models for mean concentrations were excellent for Ca and alkalinity, but less good for Mg, and did not require land use data inputs as stream water sediment composition seems to reflect all aspects of the riparian zone soil system. Predictive model forms were linear. Attempts to predict minimum values for Ca and alkalinity also were less satisfactory. This probably is due to variations in hydrological response times to individual precipitation events across the catchment. Copyright © 2010 Elsevier B.V. All rights reserved.

  20. Vertical gradients in water chemistry and age in the Northern High Plains Aquifer, Nebraska, 2003

    USGS Publications Warehouse

    McMahon, P.B.; Böhlke, J.K.; Carney, C.P.

    2007-01-01

    The northern High Plains aquifer is the primary source of water used for domestic, industrial, and irrigation purposes in parts of Colorado, Kansas, Nebraska, South Dakota, and Wyoming. Despite the aquifer’s importance to the regional economy, fundamental ground-water characteristics, such as vertical gradients in water chemistry and age, remain poorly defined. As part of the U.S. Geological Survey’s National Water-Quality Assessment Program, water samples from nested, short-screen monitoring wells installed in the northern High Plains aquifer were analyzed for major ions, nutrients, trace elements, dissolved organic carbon, pesticides, stable and radioactive isotopes, dissolved gases, and other parameters to evaluate vertical gradients in water chemistry and age in the aquifer. Chemical data and tritium and radiocarbon ages show that water in the aquifer was chemically and temporally stratified in the study area, with a relatively thin zone of recently recharged water (less than 50 years) near the water table overlying a thicker zone of older water (1,800 to 15,600 radiocarbon years). In areas where irrigated agriculture was an important land use, the recently recharged ground water was characterized by elevated concentrations of major ions and nitrate and the detection of pesticide compounds. Below the zone of agricultural influence, major-ion concentrations exhibited small increases with depth and distance along flow paths because of rock/water interactions. The concentration increases were accounted for primarily by dissolved calcium, sodium, bicarbonate, sulfate, and silica. In general, the chemistry of ground water throughout the aquifer was of high quality. None of the approximately 90 chemical constituents analyzed in each sample exceeded primary drinking-water standards.Mass-balance models indicate that changes in groundwater chemistry along flow paths in the aquifer can be accounted for by small amounts of feldspar and calcite dissolution; goethite

  1. Surface chemistry and corrosion behavior of Inconel 625 and 718 in subcritical, supercritical, and ultrasupercritical water

    NASA Astrophysics Data System (ADS)

    Rodriguez, David; Merwin, Augustus; Karmiol, Zachary; Chidambaram, Dev

    2017-05-01

    Corrosion behavior of Inconel 625 and 718 in subcritical, supercritical and ultrasupercritical water was studied as a function of temperature and time. The change in the chemistry of the as-received surface film on Inconel 625 and 718 after exposure to subcritical water at 325 °C and supercritical water at 425 °C and 527.5 °C for 2 h was studied. After exposure to 325 °C subcritical water, the CrO42- based film formed; however minor quantities of NiFexCr2-xO4 spinel compounds were observed. The oxide film formed on both alloys when exposed to supercritical water at 425 °C consisted of NiFexCr2-xO4 spinel. The surface films on both alloys were identified as NiFe2O4 when exposed to supercritical water at 527.5 °C. To characterize the fully developed oxide layer, studies were conducted at test solution temperatures of 527.5 and 600 °C. Samples were exposed to these temperatures for 24, 96, and 200 h. Surface chemistry was analyzed using X-ray diffraction, as well as Raman and X-ray photoelectron spectroscopies. Inconel 718 exhibited greater mass gain than Inconel 625 for all temperatures and exposure times. The differences in corrosion behavior of the two alloys are attributed to the lower content of chromium and increased iron content of Inconel 718 as compared to Inconel 625.

  2. Carbonate chemistry of intermediate waters in the Southwest Pacific Ocean since the Last Glacial Maximum

    NASA Astrophysics Data System (ADS)

    Allen, K. A.; Sikes, E. L.; Elmore, A.; Hoenisch, B.; deMenocal, P. B.; Rosenthal, Y.

    2013-12-01

    Shifts in ocean circulation and marine carbon storage likely played an important role in the termination of the last ice age, but the mechanisms driving these changes have not yet been fully explained. It has been suggested that a greater amount of CO2 was stored in the deep sea during glacial periods via the biologic pump and/or increased uptake by a more alkaline ocean. To quantify the relative roles of such processes, more constraints on past deep ocean alkalinity are needed. Here, we present a new record of deep water carbonate chemistry for the last 30,000 years derived from a sediment core located at 1,627 meters depth in New Zealand's Bay of Plenty. Today, this core site lies at the boundary between relatively fresh Antarctic/Tasman Intermediate Water (above), and Circumpolar Deep Water (below) with more corrosive Pacific Deep Water also intruding from the north. Trace element and stable isotopic composition of foraminiferal calcite (the epibenthic species Cibicidoides wuellerstorfi) reveal changes in bottom water carbonate chemistry during periods of atmospheric CO2 change. The boron to calcium ratio (B/Ca) in these shells indicates that deep water saturation (ΔCO32-) during the last glacial maximum (LGM) was only 5 μmol kg-1 less than the modern value of ~ 20 μmol/kg, consistent with previous work identifying the Pacific as a 'well-buffered' ocean basin on long timescales. However, reconstructed ΔCO32- values fluctuated by as much as 30 μmol/kg across the deglaciation, exhibiting the most pronounced changes between 17 and 13 ka. Together with shifts in carbon isotopes, these results imply changes in circulation and/or respired CO2 storage, and support a series of events in which major oceanographic changes are intimately linked with shifts in atmospheric circulation.

  3. Groundwater chemistry near an impoundment for produced water, Powder River Basin, Wyoming, USA

    USGS Publications Warehouse

    Healy, R.W.; Bartos, T.T.; Rice, C.A.; McKinley, M.P.; Smith, B.D.

    2011-01-01

    The Powder River Basin is one of the largest producers of coal-bed natural gas (CBNG) in the United States. An important environmental concern in the Basin is the fate of the large amounts of groundwater extracted during CBNG production. Most of this produced water is disposed of in unlined surface impoundments. A 6-year study of groundwater flow and water chemistry at one impoundment, Skewed Reservoir, has produced the most detailed data set for any impoundment in the Basin. Data were collected from a network of 21 observation wells and three suction lysimeters. A groundwater mound formed atop bedrock within initially unsaturated, unconsolidated deposits underlying the reservoir. Heterogeneity in physical and chemical properties of sediments resulted in complex groundwater flow paths and highly variable groundwater chemistry. Sulfate, bicarbonate, sodium, and magnesium were the dominant ions in all areas, but substantial variability existed in relative concentrations; pH varied from less than 3 to more than 9, and total dissolved solids concentrations ranged from less than 5000 to greater than 100,000. mg/L. Selenium was a useful tracer of reservoir water; selenium concentrations exceeded 300 ??g/L in samples obtained from 18 of the 24 sampling points. Groundwater travel time from the reservoir to a nearby alluvial aquifer (a linear distance of 177. m) was calculated at 474. days on the basis of selenium concentrations. The produced water is not the primary source of solutes in the groundwater. Naturally occurring salts and minerals within the unsaturated zone, dissolved and mobilized by infiltrating impoundment water, account for most of the solute mass in groundwater. Gypsum dissolution, cation-exchange, and pyrite oxidation appear to be important reactions. The complex geochemistry and groundwater flow paths at the study site underscore the difficulty in assessing effects of surface impoundments on water resources within the Powder River Basin. ?? 2011.

  4. Groundwater chemistry near an impoundment for produced water, Powder River Basin, Wyoming, USA

    NASA Astrophysics Data System (ADS)

    Healy, Richard W.; Bartos, Timothy T.; Rice, Cynthia A.; McKinley, Michael P.; Smith, Bruce D.

    2011-06-01

    SummaryThe Powder River Basin is one of the largest producers of coal-bed natural gas (CBNG) in the United States. An important environmental concern in the Basin is the fate of the large amounts of groundwater extracted during CBNG production. Most of this produced water is disposed of in unlined surface impoundments. A 6-year study of groundwater flow and water chemistry at one impoundment, Skewed Reservoir, has produced the most detailed data set for any impoundment in the Basin. Data were collected from a network of 21 observation wells and three suction lysimeters. A groundwater mound formed atop bedrock within initially unsaturated, unconsolidated deposits underlying the reservoir. Heterogeneity in physical and chemical properties of sediments resulted in complex groundwater flow paths and highly variable groundwater chemistry. Sulfate, bicarbonate, sodium, and magnesium were the dominant ions in all areas, but substantial variability existed in relative concentrations; pH varied from less than 3 to more than 9, and total dissolved solids concentrations ranged from less than 5000 to greater than 100,000 mg/L. Selenium was a useful tracer of reservoir water; selenium concentrations exceeded 300 μg/L in samples obtained from 18 of the 24 sampling points. Groundwater travel time from the reservoir to a nearby alluvial aquifer (a linear distance of 177 m) was calculated at 474 days on the basis of selenium concentrations. The produced water is not the primary source of solutes in the groundwater. Naturally occurring salts and minerals within the unsaturated zone, dissolved and mobilized by infiltrating impoundment water, account for most of the solute mass in groundwater. Gypsum dissolution, cation-exchange, and pyrite oxidation appear to be important reactions. The complex geochemistry and groundwater flow paths at the study site underscore the difficulty in assessing effects of surface impoundments on water resources within the Powder River Basin.

  5. Predicting LER and LWR in SAQP with 3D virtual fabrication

    NASA Astrophysics Data System (ADS)

    Gu, Jiangjiang (Jimmy); Zhao, Dalong; Allampalli, Vasanth; Faken, Daniel; Greiner, Ken; Fried, David M.

    2016-03-01

    For the first time, process impact on line-edge roughness (LER) and line-width roughness (LWR) in a back-end-of-line (BEOL) self-aligned quadruple patterning (SAQP) flow has been systematically investigated through predictive 3D virtual fabrication. This frequency dependent LER study shows that both deposition and etching effectively reduce high frequency LER, while deposition is much more effective in reducing low frequency LER. Spacer-assisted patterning technology reduces LWR significantly by creating correlated edges, and further LWR improvement can be achieved by optimizing individual process effects on LER. Our study provides a guideline for the understanding and optimization of LER and LWR in advanced technology nodes.

  6. Temporal variations of geyser water chemistry in the Upper Geyser Basin, Yellowstone National Park, USA

    USGS Publications Warehouse

    Hurwitz, Shaul; Hunt, Andrew G.; Evans, William C.

    2012-01-01

    Geysers are rare features that reflect a delicate balance between an abundant supply of water and heat and a unique geometry of fractures and porous rocks. Between April 2007 and September 2008, we sampled Old Faithful, Daisy, Grand, Oblong, and Aurum geysers in Yellowstone National Park's Upper Geyser Basin and characterized temporal variations in major element chemistry and water isotopes (δ18O, δD, 3H). We compare these temporal variations with temporal trends of Geyser Eruption Intervals (GEI). SiO2 concentrations and geothermometry indicate that the geysers are fed by waters ascending from a reservoir with temperatures of ∼190 to 210°C. The studied geysers display small and complex chemical and isotopic seasonal variations, and geysers with smaller volume display larger seasonal variations than geysers with larger volumes. Aurum and Oblong Geysers contain detectable tritium concentrations, suggesting that erupted water contains some modern meteoric water. We propose that seasonal GEI variations result from varying degrees of evaporation, meteoric water recharge, water table fluctuations, and possible hydraulic interaction with the adjacent Firehole River. We demonstrate that the concentrations of major dissolved species in Old Faithful Geyser have remained nearly constant since 1884 despite large changes in Old Faithful's eruption intervals, suggesting that no major changes have occurred in the hydrothermal system of the Upper Geyser Basin for >120 years. Our data set provides a baseline for monitoring future changes in geyser activity that might result from varying climate, earthquakes, and changes in heat flow from the underlying magmatic system.

  7. Temporal variations of geyser water chemistry in the Upper Geyser Basin, Yellowstone National Park, USA

    NASA Astrophysics Data System (ADS)

    Hurwitz, Shaul; Hunt, Andrew G.; Evans, William C.

    2012-12-01

    Geysers are rare features that reflect a delicate balance between an abundant supply of water and heat and a unique geometry of fractures and porous rocks. Between April 2007 and September 2008, we sampled Old Faithful, Daisy, Grand, Oblong, and Aurum geysers in Yellowstone National Park's Upper Geyser Basin and characterized temporal variations in major element chemistry and water isotopes (δ18O, δD, 3H). We compare these temporal variations with temporal trends of Geyser Eruption Intervals (GEI). SiO2 concentrations and geothermometry indicate that the geysers are fed by waters ascending from a reservoir with temperatures of ˜190 to 210°C. The studied geysers display small and complex chemical and isotopic seasonal variations, and geysers with smaller volume display larger seasonal variations than geysers with larger volumes. Aurum and Oblong Geysers contain detectable tritium concentrations, suggesting that erupted water contains some modern meteoric water. We propose that seasonal GEI variations result from varying degrees of evaporation, meteoric water recharge, water table fluctuations, and possible hydraulic interaction with the adjacent Firehole River. We demonstrate that the concentrations of major dissolved species in Old Faithful Geyser have remained nearly constant since 1884 despite large changes in Old Faithful's eruption intervals, suggesting that no major changes have occurred in the hydrothermal system of the Upper Geyser Basin for >120 years. Our data set provides a baseline for monitoring future changes in geyser activity that might result from varying climate, earthquakes, and changes in heat flow from the underlying magmatic system.

  8. Linking catchment characteristics and water chemistry with the ecological status of Irish rivers.

    PubMed

    Donohue, Ian; McGarrigle, Martin L; Mills, Paul

    2006-01-01

    Requirements of the EU Water Framework Directive for the introduction of ecological quality objectives for surface waters and the stipulation that all surface waters in the EU must be of 'good' ecological status by 2015 necessitate a quantitative understanding of the linkages among catchment attributes, water chemistry and the ecological status of aquatic ecosystems. Analysis of lotic ecological status, as indicated by an established biotic index based primarily on benthic macroinvertebrate community structure, of 797 hydrologically independent river sites located throughout Ireland showed highly significant inverse associations between the ecological status of rivers and measures of catchment urbanisation and agricultural intensity, densities of humans and cattle and chemical indicators of water quality. Stepwise logistic regression suggested that urbanisation, arable farming and extent of pasturelands are the principal factors impacting on the ecological status of streams and rivers in Ireland and that the likelihood of a river site complying with the demands of the EU Water Framework Directive, and be of 'good' ecological status, can be predicted with reasonable accuracy using simple models that utilise either widely available landcover data or chemical monitoring data. Non-linear landcover and chemical 'thresholds' derived from these models provide a useful tool in the management of risk in catchments, and suggest strongly that more careful planning of land use in Ireland is essential in order to restore and maintain water quality as required by the Directive.

  9. Effects of flow and water chemistry on lead release rates from pipe scales.

    PubMed

    Xie, Yanjiao; Giammar, Daniel E

    2011-12-01

    Lead release from pipe scales was investigated under different water compositions, stagnation times, and flow regimes. Pipe scales containing PbO(2) and hydrocerussite (Pb(3)(OH)(2)(CO(3))(2)) were developed on lead pipes by conditioning the pipes with water containing free chlorine for eight months. Water chemistry and the composition of the pipe scales are two key factors affecting lead release from pipe scales. The water rarely reached equilibrium with pipe scales within one day, which makes solid-water contact time and corrosion product dissolution rates the controlling factors of lead concentrations for the conditions tested. Among five water compositions studied, a solution with orthophosphate had the lowest dissolved lead release rate and highest particulate lead release rate. Free chlorine also decreased the dissolved lead release rate at stagnant conditions. Water flow increased rates of release of both dissolved and particulate lead by accelerating the mass transfer of lead out of the porous pipe scales and by physically destabilizing pipe scales. Dissolved lead comprised the majority of the lead released at both stagnant and laminar flow conditions. Copyright © 2011 Elsevier Ltd. All rights reserved.

  10. Geology, Streamflow, and Water Chemistry of the Talufofo Stream Basin, Saipan, Northern Mariana Islands

    USGS Publications Warehouse

    Izuka, Scot K.; Ewart, Charles J.

    1995-01-01

    A study of the geology, streamflow, and water chemistry of Talufofo Stream Basin, Saipan, Commonwealth of the Northern Mariana Islands, was undertaken to determine the flow characteristics of Talufofo Stream and the relation to the geology of the drainage basin. The Commonwealth government is exploring the feasibility of using water from Talufofo Stream to supplement Saipan's stressed municipal water supply. Streamflow records from gaging stations on the principal forks of Talufofo Stream indicate that peak streamflows and long-term average flow are higher at the South Fork gaging station than at the Middle Fork gaging station because the drainage area of the South Fork gaging station is larger, but persistent base flow from ground-water discharge during dry weather is greater in the Middle Fork gaging station. The sum of the average flows at the Middle Fork and South Fork gaging stations, plus an estimate of the average flow at a point in the lower reaches of the North Fork, is about 2.96 cubic feet per second or 1.91 million gallons per day. Although this average represents the theoretical maximum long-term draft rate possible from the Talufofo Stream Basin if an adequate reservoir can be built, the actual amount of surface water available will be less because of evaporation, leaks, induced infiltration, and reservoir-design constraints. Base-flow characteristics, such as stream seepage and spring discharge, are related to geology of the basin. Base flow in the Talufofo Stream Basin originates as discharge from springs near the base of limestones located in the headwaters of Talufofo Stream, flows over low-permeability volcanic rocks in the middle reaches, and seeps back into the high-permeability limestones in the lower reaches. Water sampled from Talufofo Stream during base flow had high dissolved-calcium concentrations (between 35 and 98 milligrams per liter), characteristic of water from a limestone aquifer. Concentrations of potassium, sodium, and chloride

  11. Probing the chemistry, structure, and dynamics of the water-silica interface

    NASA Astrophysics Data System (ADS)

    Lockwood, Glenn K.

    Despite its natural abundance and wide-ranging technological relevance, much remains unknown or unclear about water-silica interfaces. Computer simulation stands to bridge the gaps of knowledge left by experiment, and a recently developed Dissociative Water Potential has enabled the simulation of large amorphous silica surfaces in contact with water without having to impose a model of surface chemistry a priori. Earlier work with this model has revealed the existence of several protonated surface sites such as SiOH2 + and Si-(OH+)-Si that have yet to be extensively characterized. However, both experiment and quantum mechanical simulation have provided an increasing body of evidence that suggests these sites exist, and these sites may play key roles in some of the unexplained phenomena observed in water-silica systems. To this end, this Dissociative Water Potential has been applied to develop a comprehensive picture of the chemistry, structure, and dynamics of the water-silica interface that is unbiased by any expectation of what sites should form. The bridging OH site, Si-(OH+)-Si, does form and is characterized as a highly acidic site that occurs predominantly on strained Si-O-Si bridges near the interface. Similarly, the transient formation of SiOH2 + is observed, and this site is found to be more acidic than Si-(OH +)-Si. In addition to H3O+ that forms near the interface, all of these sites readily deprotonate and are expected to play a role in the enhanced proton conductivity experimentally observed in hydrated mesoporous silica. The reactions between water and silica are particularly relevant to the engineering of nuclear waste forms, and the role of water-silica interactions are also explored within the context of the degradation of silica-based waste forms exposed to radiation. Despite the significant simulation effort employed in glassy waste form research, no molecular models of radiation damage in silica include the effects of moisture. This deficiency is

  12. LWR fuel assembly designs for the transmutation of LWR Spent Fuel TRU with FCM and UO{sub 2}-ThO{sub 2} Fuels

    SciTech Connect

    Bae, G.; Hong, S. G.

    2013-07-01

    In this paper, transmutation of transuranic (TRU) nuclides from LWR spent fuels is studied by using LWR fuel assemblies which consist of UO{sub 2}-ThO{sub 2} fuel pins and FCM (Fully Ceramic Microencapsulated) fuel pins. TRU from LWR spent fuel is loaded in the kernels of the TRISO particle fuels of FCM fuel pins. In the FCM fuel pins, the TRISO particle fuels are distributed in SiC matrix having high thermal conductivity. The loading patterns of fuel pins and the fuel compositions are searched to have high transmutation rate and feasible neutronic parameters including pin power peaking, temperature reactivity coefficients, and cycle length. All studies are done only in fuel assembly calculation level. The results show that our fuel assembly designs have good transmutation performances without multi-recycling and without degradation of the safety-related neutronic parameters. (authors)

  13. Evaluating the effects of variable water chemistry on bacterial transport during infiltration.

    PubMed

    Zhang, Haibo; Nordin, Nahjan Amer; Olson, Mira S

    2013-07-01

    Bacterial infiltration through the subsurface has been studied experimentally under different conditions of interest and is dependent on a variety of physical, chemical and biological factors. However, most bacterial transport studies fail to adequately represent the complex processes occurring in natural systems. Bacteria are frequently detected in stormwater runoff, and may present risk of microbial contamination during stormwater recharge into groundwater. Mixing of stormwater runoff with groundwater during infiltration results in changes in local solution chemistry, which may lead to changes in both bacterial and collector surface properties and subsequent bacterial attachment rates. This study focuses on quantifying changes in bacterial transport behavior under variable solution chemistry, and on comparing the influences of chemical variability and physical variability on bacterial attachment rates. Bacterial attachment rate at the soil-water interface was predicted analytically using a combined rate equation, which varies temporally and spatially with respect to changes in solution chemistry. Two-phase Monte Carlo analysis was conducted and an overall input-output correlation coefficient was calculated to quantitatively describe the importance of physiochemical variation on the estimates of attachment rate. Among physical variables, soil particle size has the highest correlation coefficient, followed by porosity of the soil media, bacterial size and flow velocity. Among chemical variables, ionic strength has the highest correlation coefficient. A semi-reactive microbial transport model was developed within HP1 (HYDRUS1D-PHREEQC) and applied to column transport experiments with constant and variable solution chemistries. Bacterial attachment rates varied from 9.10×10(-3)min(-1) to 3.71×10(-3)min(-1) due to mixing of synthetic stormwater (SSW) with artificial groundwater (AGW), while bacterial attachment remained constant at 9.10×10(-3)min(-1) in a constant

  14. The calculation of quality indices of the water heat carrier and estimation of the condition of water chemistry of drum boilers

    NASA Astrophysics Data System (ADS)

    Larin, B. M.; Larin, A. B.; Kozyulina, E. V.; Kolegov, A. V.

    2012-07-01

    There is suggested a method for an indirect calculated identification of ionic impurities in water of drum boilers ( p b = 13.8 MPa) by means of measuring the electric conductivity of cooled samples (direct and H-cationized ones) of the feedwater and drum water. This paper reports the results of an industrial experiment carried out on the drum power boiler during the entire heating season. The possibility of evaluating the condition of the water chemistry, with plotting a phase diagram of the phosphate-based water chemistry and determining characteristic dependences, is shown.

  15. Influence of Water Table Depth on Pore Water Chemistry and Trihalomethane Formation Potential in Peatlands.

    PubMed

    Gough, Rachel; Holliman, Peter J; Fenner, Nathalie; Peacock, Mike; Freeman, Christopher

    2016-02-01

    Drained peatland catchments are reported to produce more colored, dissolved organic carbon (DOC)-rich water, presenting problems for potable water treatment. The blocking of peatland drainage ditches to restore the water table is increasingly being considered as a strategy to address this deterioration in water quality. However, the effect of ditch blocking on the potential of DOC to form trihalomethanes (THMs) has not been assessed. In this study, the effect of peat rewetting on pore water DOC concentration and characteristics (including THM formation potential [THMFP]) was assessed over 12 months using peat cores collected from two drained peatland sites. The data show little evidence of differences in DOC concentration or characteristics between the different treatments. The absence of any difference in the THMFP of pore water between treatments suggests that, in the short term at least, ditch blocking may not have an effect on the THMFP of waters draining peatland catchments.

  16. Sulfur isotopic composition and water chemistry in water from the High Plains aquifer, Oklahoma Panhandle and southwestern Kansas

    USGS Publications Warehouse

    Krothe, Noel C.; Oliver, Joseph W.

    1982-01-01

    The Ogallala Formation comprises the High Plains aquifer in Oklahoma and southwestern Kansas. Regional ground-water flow is from west to east in the Ogallala Formation, and the concentration of dissolved solids in ground water increases in the direction of flow. This increase may be influenced by residence time, but underlying bedrock appears to control ground-water chemistry. The Ogallala Formation is underlain by Mesozoic rocks in the west and Permian rocks in the east. Mean concentration of dissolved solids in ground water from the Mesozoic rocks is 552 milligrams per liter and Permian rocks is 4,720 milligrams per liter. Mean concentration of dissolved solids for water in the Ogallala Formation is 396 milligrams per liter where it overlies Mesozoic rocks and 569 milligrams per liter where it overlies Permian rocks. Del sulfur-34 sulfate values range from a high of +6.9 parts per thousand to a low of -25.1 parts per thousand. Sulfate increases from about 20 milligrams per liter to more than 350 milligrams per liter from west to east. Increasing concentration of dissolved solids, lighter Del sulfur-34 values, and increasing sulfate concentration in the east implies that ground water or hydrogen sulfide from Permian rocks may be moving upward into the Ogallala Formation. (USGS)

  17. Impact of implicit effects on uncertainties and sensitivities of the Doppler coefficient of a LWR pin cell

    NASA Astrophysics Data System (ADS)

    Hursin, Mathieu; Leray, Olivier; Perret, Gregory; Pautz, Andreas; Bostelmann, Friederike; Aures, Alexander; Zwermann, Winfried

    2017-09-01

    In the present work, PSI and GRS sensitivity analysis (SA) and uncertainty quantification (UQ) methods, SHARK-X and XSUSA respectively, are compared for reactivity coefficient calculation; for reference the results of the TSUNAMI and SAMPLER modules of the SCALE code package are also provided. The main objective of paper is to assess the impact of the implicit effect, e.g., considering the effect of cross section perturbation on the self-shielding calculation, on the Doppler coefficient SA and UQ. Analyses are done for a Light Water Reactor (LWR) pin cell based on Phase I of the UAM LWR benchmark. The negligence of implicit effects in XSUSA and TSUNAMI leads to deviations of a few percent between the sensitivity profiles compared to SAMPLER and TSUNAMI (incl. implicit effects) except for 238U elastic scattering. The implicit effect is much larger for the SHARK-X calculations because of its coarser energy group structure between 10 eV and 10 keV compared to the applied SCALE libraries. It is concluded that the influence of the implicit effect strongly depends on the energy mesh of the nuclear data library of the neutron transport solver involved in the UQ calculations and may be magnified by the response considered.

  18. Hydrogeology and water chemistry of Montezuma Well in Montezuma Castle National Monument and surrounding area, Arizona

    USGS Publications Warehouse

    Konieczki, Alice D.; Leake, Stanley A.

    1997-01-01

    Increasing population and associated residential and commercial development have greatly increased water use and consumption in the Verde Valley near Montezuma Well, a unit of Montezuma Castle National Monument in central Arizona. Flow from Montezuma Well and water levels in eight wells that are measured annually do not indicate that the ground-water system has been affected by development. Additional data are needed to develop an adequate ground-water monitoring program so that future effects of development can be detected. Monitoring the ground-water system would detect changes in discharge from the Montezuma Well or changes in the ground-water system that might indicate a potential change of flow to the well. Water samples were collected, and field measurements of specific conductance, pH, temperature, and dissolved oxygen were made throughout the pond at Montezuma Well during an exploration in May 1991. The exploration included two fissures in the bottom of the pond that were filled with sand. The sand in the fissures was kept in suspension by water entering the pond. Water chemistry indicates that the ground water from the area is a mixed combination of calcium, magnesium, sodium, and bicarbonate type water. The analyses for 18O/16O and 2H/1H show that the water from the wells and springs in the area, including Montezuma Well, has been exposed to similar environmental conditions and could have had similar flow paths. The MODFLOW finite-difference ground-water model was used to develop an uncalibrated interpretive model to study possible mechanisms for discharge of water at Montezuma Well. The study presents the hypothesis that ground water in the Supai Formation is the source of discharge to Montezuma Well because of the differences between the surface elevation of the pond at Montezuma Well and the stage in the adjacent Wet Beaver Creek. A series of simulations shows that upward flow from the Supai Formation is a possible mechanism for discharge to Montezuma

  19. The millennium water vapour drop in chemistry-climate model simulations

    NASA Astrophysics Data System (ADS)

    Brinkop, Sabine; Dameris, Martin; Jöckel, Patrick; Garny, Hella; Lossow, Stefan; Stiller, Gabriele

    2016-07-01

    This study investigates the abrupt and severe water vapour decline in the stratosphere beginning in the year 2000 (the "millennium water vapour drop") and other similarly strong stratospheric water vapour reductions by means of various simulations with the state-of-the-art Chemistry-Climate Model (CCM) EMAC (ECHAM/MESSy Atmospheric Chemistry Model). The model simulations differ with respect to the prescribed sea surface temperatures (SSTs) and whether nudging is applied or not. The CCM EMAC is able to most closely reproduce the signature and pattern of the water vapour drop in agreement with those derived from satellite observations if the model is nudged. Model results confirm that this extraordinary water vapour decline is particularly obvious in the tropical lower stratosphere and is related to a large decrease in cold point temperature. The drop signal propagates under dilution to the higher stratosphere and to the poles via the Brewer-Dobson circulation (BDC). We found that the driving forces for this significant decline in water vapour mixing ratios are tropical sea surface temperature (SST) changes due to a coincidence with a preceding strong El Niño-Southern Oscillation event (1997/1998) followed by a strong La Niña event (1999/2000) and supported by the change of the westerly to the easterly phase of the equatorial stratospheric quasi-biennial oscillation (QBO) in 2000. Correct (observed) SSTs are important for triggering the strong decline in water vapour. There are indications that, at least partly, SSTs contribute to the long period of low water vapour values from 2001 to 2006. For this period, the specific dynamical state of the atmosphere (overall atmospheric large-scale wind and temperature distribution) is important as well, as it causes the observed persistent low cold point temperatures. These are induced by a period of increased upwelling, which, however, has no corresponding pronounced signature in SSTs anomalies in the tropics. Our free

  20. Research in Physical Chemistry and Chemical Education: Part A--Water Mediated Chemistry of Oxidized Atmospheric Compounds Part B--The Development of Surveying Tools to Determine How Effective Laboratory Experiments Contribute to Student Conceptual Understanding

    ERIC Educational Resources Information Center

    Maron, Marta Katarzyna

    2011-01-01

    This dissertation is a combination of two research areas, experimental physical chemistry, Chapters I to V, and chemical education, Chapters VI to VII. Chapters I to V describe research on the water-mediated chemistry of oxidized atmospheric molecules and the impact that water has on the spectra of these environmental systems. The role of water…

  1. Research in Physical Chemistry and Chemical Education: Part A--Water Mediated Chemistry of Oxidized Atmospheric Compounds Part B--The Development of Surveying Tools to Determine How Effective Laboratory Experiments Contribute to Student Conceptual Understanding

    ERIC Educational Resources Information Center

    Maron, Marta Katarzyna

    2011-01-01

    This dissertation is a combination of two research areas, experimental physical chemistry, Chapters I to V, and chemical education, Chapters VI to VII. Chapters I to V describe research on the water-mediated chemistry of oxidized atmospheric molecules and the impact that water has on the spectra of these environmental systems. The role of water…

  2. Water and gas chemistry of Lake Nyos and its bearing on the eruptive process

    NASA Astrophysics Data System (ADS)

    Giggenbach, W. F.

    1990-08-01

    The isotopic and chemical composition of water samples collected from Lake Nyos some two and eight weeks after the eruption of August 21, 1986 point to the existence of three distinct mixing regimes involving three water components. An essentially homogeneous, unmixed body of water at depths > 100 m, overlain by water increasingly affected by surface evaporation and a 5-10-m layer containing recent, but pre-eruption rain water. The cationic constituents (Na, K, Mg, Ca, Mn, Fe) of the lake water correspond to the dissolution of around 0.1 g of local rock, the waters are close to saturation with respect to siderite. The composition of the gas dissolved in the deep lake waters (0.65% b.w. of CO 2, PCO 2 = 4.4b) corresponds (in mmol mol -1) to 996 CO 2, 2.0 CH 4, 2.0 N 2, 0.05 Ar, 0.004 He, 0.0002 H 2, 0.0001 Ne, < 0.01 O 2, < 0.004 H 2S, < 0.001 CO. The isotopic compositions of CO 2 (δ 13C = -3.4‰ ) and of He ( Rair = 5.5) suggest deep magmatic origins, the 13C and 2H content of CH 4 organic sedimentary origin, the presence of aromatic hydrocarbons indicates very high temperatures of hydrocarbon formation. Exsolution of gas will first lead to the precipitation of siderite then iron hydroxide. The chemistry of the lake waters points to a loss of some 240,000 t of CO 2 from the upper 100 m of the lake, their isotopic composition is consistent with the assumption that the eruption was triggered by the accumulation of cold rain waters at the lake surface prior to the eruption inducing partial convective overturn. There is no need to invoke addition of chemical or isotopic constituents from deeper levels during the eruption.

  3. Relationships between water and gas chemistry in mature coalbed methane reservoirs of the Black Warrior Basin

    USGS Publications Warehouse

    Pashin, Jack C.; McIntyre-Redden, Marcella R.; Mann, Steven D.; Kopaska-Merkel, David C.; Varonka, Matthew S.; Orem, William H.

    2014-01-01

    Water and gas chemistry in coalbed methane reservoirs of the Black Warrior Basin reflects a complex interplay among burial processes, basin hydrodynamics, thermogenesis, and late-stage microbial methanogenesis. These factors are all important considerations for developing production and water management strategies. Produced water ranges from nearly potable sodium-bicarbonate water to hypersaline sodium-chloride brine. The hydrodynamic framework of the basin is dominated by structurally controlled fresh-water plumes that formed by meteoric recharge along the southeastern margin of the basin. The produced water contains significant quantities of hydrocarbons and nitrogen compounds, and the produced gas appears to be of mixed thermogenic-biogenic origin.Late-stage microbial methanogenesis began following unroofing of the basin, and stable isotopes in the produced gas and in mineral cements indicate that late-stage methanogenesis occurred along a CO2-reduction metabolic pathway. Hydrocarbons, as well as small amounts of nitrate in the formation water, probably helped nourish the microbial consortia, which were apparently active in fresh to hypersaline water. The produced water contains NH4+ and NH3, which correlate strongly with brine concentration and are interpreted to be derived from silicate minerals. Denitrification reactions may have generated some N2, which is the only major impurity in the coalbed gas. Carbon dioxide is a minor component of the produced gas, but significant quantities are dissolved in the formation water. Degradation of organic compounds, augmented by deionization of NH4+, may have been the principal sources of hydrogen facilitating late-stage CO2 reduction.

  4. Chemistry of calcium carbonate-rich shallow water sediments in the Bahamas

    SciTech Connect

    Morse, J.W.; Zullig, J.J.; Bernstein, L.D.; Millero, F.J.; Milne, P.; Mucci, A.; Choppin, G.R.

    1985-02-01

    The geochemistry of calcium carbonate-rich sediments from a variety of environments throughout the Bahamas was investigated with particular emphasis on the factors that control the pore water chemistry. Most sediments are supersaturated with respect to aragonite, the most abundant carbonate component. Experimental studies indicate that the observed in situ calcium carbonate ion activity products can often be produced as reversible metastable equilibria between the sediments and seawater. This is interpreted as being the result of interactions between the solutions and the minor high Mg-calcite component present in these sediments. Although the overlying waters are more supersaturated than the pore waters, carbonate dissolution, not precipitation, dominates in these sediments as a result of organic matter oxidation and the resulting increase in P/sub CO/sub 2//. The carbonate sediments of the Bahamas are remarkable for their purity, with the exception of special environments such as mangrove swamps and tidal flats with algal mats. Organic matter and heavy metal content is extremely low. Only minor sulfate reduction is occurring in most sediments. Phosphate is undetectable in all pore waters, probably as a result of adsorption on carbonate mineral surfaces. Other dissolved pore water components such as ammonia and DOC are much lower than typically found in shallow water fine-grained terrigeneous sediments.

  5. Water as Life, Death, and Power: Building an Integrated Interdisciplinary Course Combining Perspectives from Anthropology, Biology, and Chemistry

    ERIC Educational Resources Information Center

    Willermet, Cathy; Mueller, Anja; Juris, Stephen J.; Drake, Eron; Upadhaya, Samik; Chhetri, Pratik

    2013-01-01

    In response to a request from a campus student organization, faculty from three fields came together to develop and teach an integrated interdisciplinary course on water issues and social activism. This course, "Water as Life, Death, and Power", brought together topics from the fields of anthropology, biology and chemistry to explore…

  6. A study of water chemistry extends the benefits of using silica-based nanoparticles on enhanced oil recovery

    NASA Astrophysics Data System (ADS)

    Hendraningrat, Luky; Torsæter, Ole

    2016-01-01

    Chemistry of the injected water has been investigated as an important parameter to improve/enhance oil recovery (IOR/EOR). Numerous extensive experiments have observed that water chemistry, such as ionic composition and salinity, can be modified for IOR/EOR purposes. However, the possible oil displacement mechanism remains debatable. Nanoparticle recently becomes more popular that have shown a great potential for IOR/EOR purposes in lab-scale, where in most experiments, water-based fluid were used as dispersed fluid. As yet, there has been no discussion in the literature on the study of water chemistry on enhanced oil recovery using silica-based nanoparticles. A broad range of laboratory studies involving rock, nanoparticles and fluid characterization; fluid-fluid and fluid-rock interactions; surface conductivity measurement; coreflood experiment; injection strategy formulation; filtration mechanism and contact angle measurement are conducted to investigate the impact of water chemistry, such as water salinity and ionic composition including hardness cations, on the performance of silica-based nanoparticles in IOR/EOR process and reveal possible displacement mechanism. The experimental results demonstrated that water salinity and ionic composition significantly impacted oil recovery using hydrophilic silica-based nanoparticles and that the oil recovery increased with the salinity. The primary findings from this study are that the water salinity, the ionic composition and the injection strategy are important parameters to be considered in Nano-EOR.

  7. Hydrology and Species-Specific Effects of Bacopa monnieri and Leersia oryzoides on Soil and Water Chemistry

    USDA-ARS?s Scientific Manuscript database

    In an eight week greenhouse experiment, Bacopa monnieri (Water Hyssop) and Leersia oryzoides (Rice Cutgrass) were compared for nutrient assimilation as well as soil and water chemistry under variable flooding regimes using a nutrient solution rich in nitrogen (N) and phosphorus (P). Soil redox poten...

  8. Responses of soil and water chemistry to mountain pine beetle induced tree mortality in Grand County, Colorado, USA

    Treesearch

    David W. Clow; Charles C. Rhoades; Jennifer Briggs; Megan Caldwell; William M. Lewis

    2011-01-01

    Pine forest in northern Colorado and southern Wyoming, USA, are experiencing the most severe mountain pine beetle epidemic in recorded history, and possible degradation of drinking-water quality is a major concern. The objective of this study was to investigate possible changes in soil and water chemistry in Grand County, Colorado in response to the epidemic,...

  9. Relationships of surface water, pore water, and sediment chemistry in wetlands adjacent to Great Salt Lake, Utah, and potential impacts on plant community health.

    PubMed

    Carling, Gregory T; Richards, David C; Hoven, Heidi; Miller, Theron; Fernandez, Diego P; Rudd, Abigail; Pazmino, Eddy; Johnson, William P

    2013-01-15

    We collected surface water, pore water, and sediment samples at five impounded wetlands adjacent to Great Salt Lake, Utah, during 2010 and 2011 in order to characterize pond chemistry and to compare chemistry with plant community health metrics. We also collected pore water and sediment samples along multiple transects at two sheet flow wetlands during 2011 to investigate a potential link between wetland chemistry and encroachment of invasive emergent plant species. Samples were analyzed for a suite of trace and major elements, nutrients, and relevant field parameters. The extensive sampling campaign provides a broad assessment of Great Salt Lake wetlands, including a range of conditions from reference to highly degraded. We used nonmetric multidimensional scaling (NMS) to characterize the wetland sites based on the multiple parameters measured in surface water, pore water, and sediment. NMS results showed that the impounded wetlands fall along a gradient of high salinity/low trace element concentrations to low salinity/high trace element concentrations, whereas the sheet flow wetlands have both elevated salinity and high trace element concentrations, reflecting either different sources of element loading or different biogeochemical/hydrological processes operating within the wetlands. Other geochemical distinctions were found among the wetlands, including Fe-reducing conditions at two sites and sulfate-reducing conditions at the remaining sites. Plant community health metrics in the impounded wetlands showed negative correlations with specific metal concentrations in sediment (THg, Cu, Zn, Cd, Sb, Pb, Ag, Tl), and negative correlations with nutrient concentrations in surface water (nitrite, phosphate, nitrate). In the sheet flow wetlands, invasive plant species were inversely correlated with pore water salinity. These results indicate that sediment and pore water chemistry play an important role in wetland plant community health, and that monitoring and

  10. Impact of water chemistry on the particle-specific toxicity of copper nanoparticles to Daphnia magna.

    PubMed

    Xiao, Yinlong; Peijnenburg, Willie J G M; Chen, Guangchao; Vijver, Martina G

    2018-01-01

    Toxicity of metallic nanoparticle suspensions (NP(total)) is generally assumed to result from the combined effect of the particles present in suspensions (NP(particle)) and their released ions (NP(ion)). Evaluation and consideration of how water chemistry affects the particle-specific toxicity of NP(total) are critical for environmental risk assessment of nanoparticles. In this study, it was found that the toxicity of Cu NP(particle) to Daphnia magna, in line with the trends in toxicity for Cu NP(ion), decreased with increasing pH and with increasing concentrations of divalent cations and dissolved organic carbon (DOC). Without the addition of DOC, the toxicity of Cu NP(total) to D. magna at the LC50 was driven mainly by Cu NP(ion) (accounting for ≥53% of the observed toxicity). However, toxicity of Cu NP(total) in the presence of DOC at a concentration ranging from 5 to 50mg C/L largely resulted from the NP(particle) (57%-85%), which could be attributable to the large reduction of the concentration of Cu NP(ion) and the enhancement of the stability of Cu NP(particle) when DOC was added. Our results indicate that water chemistry needs to be explicitly taken into consideration when evaluating the role of NP(particle) and NP(ion) in the observed toxicity of NP(total). Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Prebiotic chemistry in eutectic solutions at the water-ice matrix.

    PubMed

    Menor-Salván, César; Marín-Yaseli, Margarita R

    2012-08-21

    A crystalline ice matrix at subzero temperatures can maintain a liquid phase where organic solutes and salts concentrate to form eutectic solutions. This concentration effect converts the confined reactant solutions in the ice matrix, sometimes making condensation and polymerisation reactions occur more favourably. These reactions occur at significantly high rates from a prebiotic chemistry standpoint, and the labile products can be protected from degradation. The experimental study of the synthesis of nitrogen heterocycles at the ice-water system showed the efficiency of this scenario and could explain the origin of nucleobases in the inner Solar System bodies, including meteorites and extra-terrestrial ices, and on the early Earth. The same conditions can also favour the condensation of monomers to form ribonucleic acid and peptides. Together with the synthesis of these monomers, the ice world (i.e., the chemical evolution in the range between the freezing point of water and the limit of stability of liquid brines, 273 to 210 K) is an under-explored experimental model in prebiotic chemistry.

  12. Water chemistry and its effects on the physiology and survival of Atlantic salmon Salmo salar smolts.

    PubMed

    Liebich, T; McCormick, S D; Kircheis, D; Johnson, K; Regal, R; Hrabik, T

    2011-08-01

    The physiological effects of episodic pH fluctuations on Atlantic salmon Salmo salar smolts in eastern Maine, U.S.A., were investigated. During this study, S. salar smolts were exposed to ambient stream-water chemistry conditions at nine sites in four catchments for 3 and 6 day intervals during the spring S. salar smolt migration period. Plasma chloride, plasma glucose, gill aluminium and gill Na(+)- and K(+)-ATPase levels in S. salar smolts were assessed in relation to ambient stream-water chemistry during this migration period. Changes in both plasma chloride and plasma glucose levels of S. salar smolts were strongly correlated with stream pH, and S. salar smolt mortality occurred in one study site with ambient stream pH between 5·6 and 5·8 during the study period. The findings from this study suggest that physiological effects on S. salar smolts are strongly correlated with stream pH and that in rivers and streams with low dissolved organic carbon (DOC) concentrations the threshold for physiological effects and mortality probably occurs at a higher pH and shorter exposure period than in rivers with higher DOC. Additionally, whenever an acidification event in which pH drops below 5·9 coincides with S. salar smolt migration in eastern Maine rivers, there is potential for a significant reduction in plasma ions of S. salar smolts.

  13. High-pressure photodissociation of water as a tool for hydrogen synthesis and fundamental chemistry

    PubMed Central

    Ceppatelli, Matteo; Bini, Roberto; Schettino, Vincenzo

    2009-01-01

    High-pressure methods have been demonstrated to be efficient in providing new routes for the synthesis of materials of technological interest. In several molecular compounds, the drastic pressure conditions required for spontaneous transformations have been lowered to the kilobar range by photoactivation of the reactions. At these pressures, the syntheses are accessible to large-volume applications and are of interest to bioscience, space, and environmental chemistry. Here, we show that the short-lived hydroxyl radicals, produced in the photodissociation of water molecules by near-UV radiation at room temperature and pressures of a few tenths of a gigapascal (GPa), can be successfully used to trigger chemical reactions in mixtures of water with carbon monoxide or nitrogen. The detection of molecular hydrogen among the reaction products is of particular relevance. Besides the implications in fundamental chemistry, the mild pressure and irradiation conditions, the efficiency of the process, and the nature of the reactant and product molecules suggest applications in synthesis. PMID:19581572

  14. Water chemistry and its effects on the physiology and survival of Atlantic salmon Salmo salar smolts

    USGS Publications Warehouse

    Liebich, T.; McCormick, S.D.; Kircheis, D.; Johnson, K.; Regal, R.; Hrabik, T.

    2011-01-01

    The physiological effects of episodic pH fluctuations on Atlantic salmon Salmo salar smolts in eastern Maine, U.S.A., were investigated. During this study, S. salar smolts were exposed to ambient stream-water chemistry conditions at nine sites in four catchments for 3 and 6 day intervals during the spring S. salar smolt migration period. Plasma chloride, plasma glucose, gill aluminium and gill Na+- and K+-ATPase levels in S. salar smolts were assessed in relation to ambient stream-water chemistry during this migration period. Changes in both plasma chloride and plasma glucose levels of S. salar smolts were strongly correlated with stream pH, and S. salar smolt mortality occurred in one study site with ambient stream pH between 5??6 and 5??8 during the study period. The findings from this study suggest that physiological effects on S. salar smolts are strongly correlated with stream pH and that in rivers and streams with low dissolved organic carbon (DOC) concentrations the threshold for physiological effects and mortality probably occurs at a higher pH and shorter exposure period than in rivers with higher DOC. Additionally, whenever an acidification event in which pH drops below 5??9 coincides with S. salar smolt migration in eastern Maine rivers, there is potential for a significant reduction in plasma ions of S. salar smolts. ?? 2011 The Fisheries Society of the British Isles.

  15. Hydrogeologic controls of surface-water chemistry in the Adirondack region of New York State

    USGS Publications Warehouse

    Peters, N.E.; Driscoll, C.T.

    1987-01-01

    Relationships between surface-water discharge, water chemistry, and watershed geology were investigated to evaluate factors affecting the sensitivity of drainage waters in the Adirondack region of New York to acidification by atmospheric deposition. Instantaneous discharge per unit area was derived from relationships between flow and staff-gage readings at 10 drainage basins throughout the region. The average chemical composition of the waters was assessed from monthly samples collected from July 1982 through July 1984. The ratio of flow at the 50-percent exceedence level to the flow at the 95-percent exceedence level of flow duration was negatively correlated with mean values of alkalinity or acid-neutralizing capacity (ANC), sum of basic cations (SBC), and dissolved silica, for basins containing predominantly aluminosilicate minerals and little or no carbonate-bearing minerals. Low ratios are indicative of systems in which flow is predominately derived from surface- and ground-water storage, whereas high ratios are characteristic of watersheds with variable flow that is largely derived from surface runoff. In an evaluation of two representative surface-water sites, concentrations of ANC, SBC, and dissolved silica, derived primarily from soil mineral weathering reactions. decreased with increasing flow. Furthermore, the ANC was highest at low flow when the percentage of streamflow derived from ground water was maximum. As flow increased, the ANC decreased because the contribution of dilute surface runoff and lateral flow through the shallow acidic soil horizons to total flow increased. Basins having relatively high ground-water contributions to total flow, in general, have large deposits of thick till or stratified drift. A major factor controlling the sensitivity of these streams and lakes to acidification is the relative contribution of ground water to total discharge. ?? 1987 Martinus Nijhoff/Dr W. Junk Publishers.

  16. Modeling water chemistry change and contaminant transport in riverbank filtration systems

    NASA Astrophysics Data System (ADS)

    Mustafa, Shaymaa; Bahar, Arifah; Aziz, Zainal Abdul; Suratman, Saim

    2016-06-01

    Riverbank filtration system is river water treatment approach based on natural removal of contaminants due to physical, chemical and biological processes. In this article, an analytical model is developed by using Green's function method to simulate the effects of pumping well and microbial activity that occurs in riverbed sediments on contaminant transport and evolution of water chemistry. The model is tested with data collected previously for RBF site in France. The results are compared with numerical simulation conducted in the literature by using finite difference method. Graphically, it is noticed that both numerical and analytical results have almost the same behavior. Also it is found that the model can simulate the decreasing of one pollutant concentration at the zone where the bacteria starts to consume this pollutant.

  17. Characterization of the oxide film formed on type 316 stainless steel in 288 C water in cyclic normal and hydrogen water chemistries

    SciTech Connect

    Kim, Y.J.

    1995-11-01

    Characteristics of the oxide film formed on type 316 (UNS S31600) stainless steel (SS) in 288 C water under cyclic normal water chemistry (NWC) and hydrogen water chemistry (HWC) conditions were examined by scanning electron microscopy (SEM). Transmission electron microscopy (TEM), and Auger electron spectroscopy (AES). It was found that the oxide film mainly consists of two oxide layers: an outer oxide layer with a large particle (nickel-enriched magnetite [Fe{sub 3}O{sub 4}]-type structure) and an intermediate or small particle (hematite [{alpha}-Fe{sub 2}O{sub 3}] structure) and a very fine-grain inner layer with a chromium-enriched Fe{sub 3}O{sub 4}-type structure. Under cyclic water chemistries (NWC and HWC) the existing outer oxide layer composition was shown to be dependent upon the water chemistry, while the inner oxide layer remained unaffected. This may result from the concentration gradient of oxygen through the oxide film upon changing water chemistries. It also was observed that a closely packed oxide with a small particle size formed under the NWC condition, while a less-packed oxide with a large particle size formed under the HWC condition. A thicker oxide formed under the NWC environment than under the HWC condition.

  18. Changes in surface water chemistry caused by natural forest dieback in an unmanaged mountain catchment.

    PubMed

    Kopáček, J; Fluksová, H; Hejzlar, J; Kaňa, J; Porcal, P; Turek, J

    2017-04-15

    Ionic and nutrient compositions of throughfall, tributaries and lake outlet were analysed in the Plešné catchment-lake system (an unmanaged mountain forest in Central Europe) from 1997 to 2016. The aim was to evaluate changes in surface water chemistry after natural forest dieback. In the 2004-2008, 93% of the Norway spruce trees were killed by bark beetle outbreak, and all dead biomass remained in the catchment. Forest dieback changed the chemistry of all water fluxes, and the magnitude, timing, and duration of these changes differed for individual water constituents. The most pronounced decreases in throughfall concentrations occurred for K(+), dissolved organic carbon (DOC), Ca(2+) and Mg(2+), i.e. elements mostly originating from canopy leaching, while concentrations of NH4(+) and soluble reactive phosphorus (SRP) remained almost unaffected. In tributaries, the most rapid changes were increases in NO3(-), K(+), H(+) and ionic aluminium (Ali) concentrations, while terrestrial export of DOC and P forms started more slowly. Immediately after the forest dieback, increase in NO3(-) concentrations was delayed by elevated DOC availability in soils. NO3(-) became the dominant anion, with maximum concentrations up to 346μeqL(-1) within 5-7years after the bark beetle outbreak, and then started to decrease. Terrestrial exports of Ali, K(+), H(+), Mg(2+), and Ca(2+) accompanied NO3(-) leaching, but their trends differed due to their different sources. Elevated losses of SRP, DOC, and dissolved organic nitrogen continued until the end of the study. In the lake, microbial processes significantly decreased concentrations of NO3(-), organic acid anions, H(+) and Ali, and confounded the chemical trends observed in tributaries. Our results suggest that terrestrial losses of elements and the deterioration of waters after forest dieback are less pronounced in unmanaged than managed (clear-cut) catchments. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Precipitation and river water chemistry of the Piracicaba River basin, southeast Brazil.

    PubMed

    Williams, M R; Filoso, S; Martinelli, L A; Lara, L B; Camargo, P B

    2001-01-01

    Annual precipitation and river water volumes and chemistry were measured from 1995 to 1998 in a mesoscale agricultural area of southeast Brazil. Precipitation was mildly acidic and solute concentrations were higher in the west than in the east of the basin. Combustion products from biomass burning, automobile exhaust, and industry typically accumulate in the atmosphere from March until October and are responsible for seasonal differences observed in precipitation chemistry. In river waters, the volume-weighted mean (VWM) concentrations of major solutes at 10 sites across the basin were generally lower at upriver than at downriver sampling sites for most solutes. Mass balances for major solutes indicate that, as a regional entity, the Piracicaba River basin was a net sink of H+, PO4(3-), and NH4+, and a net source of other solutes. The main stem of the Piracicaba River had a general increase in solute concentrations from upriver to downriver sampling sites. In contrast, NO3- and NH4+ concentrations increased in the mid-reach sampling sites and decreased due to immobilization or utilization in the mid-reach reservoir, and there was denitrification immediately downriver of this reservoir. Compared with tributaries of the Chesapeake Bay estuary, the Piracicaba River is affected more by point-source inputs of raw sewage and industrial wastes than nonpoint agricultural runoff high in N and P. Inputs of N and C are responsible for a degradation of water quality at downriver sampling sites of the Piracicaba River drainage, and water quality could be considerably improved by augmenting sewage treatment.

  20. Sphagnum establishment in alkaline fens: Importance of weather and water chemistry.

    PubMed

    Vicherová, Eliška; Hájek, Michal; Šmilauer, Petr; Hájek, Tomáš

    2017-02-15

    Sphagnum expansion to alkaline fens has accelerated during the last decades in Europe, leading to changes in diversity, habitat distributions and carbon storage. The causes are still not clearly understood and involve an interplay between climate change, hydrology, nutrient supply and Sphagnum physiology. We conducted a 4-year field experiment in eight fens in Central European highlands and assessed survival and establishment of individual apical shoot fragments of S. flexuosum, S. warnstorfii and S. squarrosum transplanted along the microtopographical gradient. In a laboratory experiment, we tested combined effects of desiccation and high calcium bicarbonate concentration on Sphagnum survival. We found that in unflooded positions, living shoots of Sphagnum and brown mosses lowered [Ca(2+)] and pH in their capillary water, in contrast to dead fragments; yet without differences between species. Survival and expansion of Sphagnum fragments, which did not die of acute calcium toxicity during first weeks/months, was negatively affected by dry weather and alkaline water chemistry, reflecting Sphagnum intolerance to desiccation and to combined high [Ca(2+)] and pH. Shoot fragments expanded to patches only when precipitation was high. Interestingly, non-toxic concentration of calcium bicarbonate reduced desiccation damage in Sphagnum, probably through protection of membranes or other cell components. This mechanism would facilitate Sphagnum survival in elevated, frequently desiccated microhabitats of calcareous fens such as brown-moss hummocks. However, since water-retaining capacity of few Sphagnum shoots is insufficient to change water chemistry in its surroundings, surface acidification may occur only once the environment (e.g. sufficient humidity) enabled expansion to larger mats. Then, the retained rainwater together with hardly decomposable Sphagnum litter would separate mire surface from groundwater, speeding up successional shift towards poor fens. Sphagnum

  1. Advanced multiphysics coupling for LWR fuel performance analysis

    DOE PAGES

    Hales, J. D.; Tonks, M. R.; Gleicher, F. N.; ...

    2015-10-01

    Even the most basic nuclear fuel analysis is a multiphysics undertaking, as a credible simulation must consider at a minimum coupled heat conduction and mechanical deformation. The need for more realistic fuel modeling under a variety of conditions invariably leads to a desire to include coupling between a more complete set of the physical phenomena influencing fuel behavior, including neutronics, thermal hydraulics, and mechanisms occurring at lower length scales. This paper covers current efforts toward coupled multiphysics LWR fuel modeling in three main areas. The first area covered in this paper concerns thermomechanical coupling. The interaction of these two physics,more » particularly related to the feedback effect associated with heat transfer and mechanical contact at the fuel/clad gap, provides numerous computational challenges. An outline is provided of an effective approach used to manage the nonlinearities associated with an evolving gap in BISON, a nuclear fuel performance application. A second type of multiphysics coupling described here is that of coupling neutronics with thermomechanical LWR fuel performance. DeCART, a high-fidelity core analysis program based on the method of characteristics, has been coupled to BISON. DeCART provides sub-pin level resolution of the multigroup neutron flux, with resonance treatment, during a depletion or a fast transient simulation. Two-way coupling between these codes was achieved by mapping fission rate density and fast neutron flux fields from DeCART to BISON and the temperature field from BISON to DeCART while employing a Picard iterative algorithm. Finally, the need for multiscale coupling is considered. Fission gas production and evolution significantly impact fuel performance by causing swelling, a reduction in the thermal conductivity, and fission gas release. The mechanisms involved occur at the atomistic and grain scale and are therefore not the domain of a fuel performance code. However, it is

  2. Advanced multiphysics coupling for LWR fuel performance analysis

    SciTech Connect

    Hales, J. D.; Tonks, M. R.; Gleicher, F. N.; Spencer, B. W.; Novascone, S. R.; Williamson, R. L.; Pastore, G.; Perez, D. M.

    2015-10-01

    Even the most basic nuclear fuel analysis is a multiphysics undertaking, as a credible simulation must consider at a minimum coupled heat conduction and mechanical deformation. The need for more realistic fuel modeling under a variety of conditions invariably leads to a desire to include coupling between a more complete set of the physical phenomena influencing fuel behavior, including neutronics, thermal hydraulics, and mechanisms occurring at lower length scales. This paper covers current efforts toward coupled multiphysics LWR fuel modeling in three main areas. The first area covered in this paper concerns thermomechanical coupling. The interaction of these two physics, particularly related to the feedback effect associated with heat transfer and mechanical contact at the fuel/clad gap, provides numerous computational challenges. An outline is provided of an effective approach used to manage the nonlinearities associated with an evolving gap in BISON, a nuclear fuel performance application. A second type of multiphysics coupling described here is that of coupling neutronics with thermomechanical LWR fuel performance. DeCART, a high-fidelity core analysis program based on the method of characteristics, has been coupled to BISON. DeCART provides sub-pin level resolution of the multigroup neutron flux, with resonance treatment, during a depletion or a fast transient simulation. Two-way coupling between these codes was achieved by mapping fission rate density and fast neutron flux fields from DeCART to BISON and the temperature field from BISON to DeCART while employing a Picard iterative algorithm. Finally, the need for multiscale coupling is considered. Fission gas production and evolution significantly impact fuel performance by causing swelling, a reduction in the thermal conductivity, and fission gas release. The mechanisms involved occur at the atomistic and grain scale and are therefore not the domain of a fuel performance code. However, it is possible to use

  3. Controls on Surface Water Chemistry in the Upper Merced River Basin, Yosemite National Park, California

    NASA Astrophysics Data System (ADS)

    Clow, David W.; Alisa Mast, M.; Campbell, Donald H.

    1996-05-01

    Surface water draining granitic bedrock in Yosemite National Park exhibits considerable variability in chemical composition, despite the relative homogeneity of bedrock chemistry. Other geological factors, including the jointing and distribution of glacial till, appear to exert strong controls on water composition. Chemical data from three surface water surveys in the upper Merced River basin conducted in August 1981, June 1988 and August 1991 were analysed and compared with mapped geological, hydrological and topographic features to identify the solute sources and processes that control water chemistry within the basin during baseflow. Water at most of the sampling sites was dilute, with alkalinities ranging from 26 to 77 equiv. l-1. Alkalinity was much higher in two subcatchments, however, ranging from 51 to 302 equiv. l-1. Base cations and silica were also significantly higher in these two catchments than in the rest of the watershed. Concentrations of weathering products in surface water were correlated to the fraction of each subcatchment underlain by surficial material, which is mostly glacial till. Silicate mineral weathering is the dominant control on concentrations of alkalinity, silica and base cations, and ratios of these constituents in surface water reflect the composition of local bedrock. Chloride concentrations in surface water samples varied widely, ranging from <1 to 96 equiv. l-1. The annual volume-weighted mean chloride concentration in the Merced River at the Happy Isles gauge from 1968 to 1990 was 26 equiv. l-1, which was five times higher than in atmospheric deposition (4-5 equiv. l-1), suggesting that a source of chloride exists within the watershed. Saline groundwater springs, whose locations are probably controlled by vertical jointing in the bedrock, are the most likely source of the chloride. Sulphate concentrations varied much less than most other solutes, ranging from 3 to 14 equiv. l-1. Concentrations of sulphate in quarterly samples

  4. Controls on surface water chemistry in the upper Merced River basin, Yosemite National Park, California

    USGS Publications Warehouse

    Clow, D.W.; Mast, M.A.; Campbell, D.H.

    1996-01-01

    Surface water draining granitic bedrock in Yosemite National Park exhibits considerable variability in chemical composition, despite the relative homogeneity of bedrock chemistry. Other geological factors, including the jointing and distribution of glacial till, appear to exert strong controls on water composition. Chemical data from three surface water surveys in the upper Merced River basin conducted in August 1981, June 1988 and August 1991 were analysed and compared with mapped geological, hydrological and topographic features to identify the solute sources and processes that control water chemistry within the basin during baseflow. Water at most of the sampling sites was dilute, with alkalinities ranging from 26 to 77 ??equiv. 1-1. Alkalinity was much higher in two subcatchments, however, ranging from 51 to 302 ??equiv. 1-1. Base cations and silica were also significantly higher in these two catchments than in the rest of the watershed. Concentrations of weathering products in surface water were correlated to the fraction of each subcatchment underlain by surficial material, which is mostly glacial till. Silicate mineral weathering is the dominant control on concentrations of alkalinity, silica and base cations, and ratios of these constituents in surface water reflect the composition of local bedrock, Chloride concentrations in surface water samples varied widely, ranging from <1 to 96 ??equiv. 1-1. The annual volume-weighted mean chloride concentration in the Merced River at the Happy Isles gauge from 1968 to 1990 was 26 ??equiv. 1-1, which was five times higher than in atmospheric deposition (4-5 ??equiv. 1-1), suggesting that a source of chloride exists within the watershed. Saline groundwater springs, whose locations are probably controlled by vertical jointing in the bedrock, are the most likely source of the chloride. Sulphate concentrations varied much less than most other solutes, ranging from 3 to 14 ??equiv. 1-1. Concentrations of sulphate in

  5. 11-Year change in water chemistry of large freshwater Reservoir Danjiangkou, China

    NASA Astrophysics Data System (ADS)

    Li, Siyue; Ye, Chen; Zhang, Quanfa

    2017-08-01

    Danjiangkou Reservoir, an important drinking water source, has become a hot spot internationally due to its draining catchment has been increasingly affected by anthropogenic activities. However, its natural water chemistry (major elements) received little attention though it is crucial for water quality and aquatic ecology. Major ions during 2004-2014 were determined using stoichiometry to explore their shifts and the driving factors in the Danjiangkou Reservoir. Results show significant differences in monthly, spatial and annual concentrations of major ions. Waters are controlled by carbonate weathering with the dominant ions of Ca2+ and HCO3- total contributing 74% to the solutes, which are consistent with regional geography. Carbonate dissolution was produced by sulfuric acid and carbonic acid in particular. The relative abundance of Ca2+ gradually decreases, Na+ + K+ abundance, however, has doubled in the recent 11 years. Population and human activities were the major drivers for several major ions, i.e., Cl- and Na+ concentrations were explained by population and GDP, and SO42- by GDP, industrial sewage and energy consumption. Estimation indicated that domestic salts and atmospheric deposition contributed 56% and 22% to Cl-, respectively. We conclude waters in the Reservoir are naturally controlled by rock weathering whilst some key elements largely contributed by anthropogenic activities.

  6. Anthropogenic impact on water chemistry and benthic macroinvertebrate associated changes in a southern Nigeria stream.

    PubMed

    Arimoro, Francis O; Odume, O Nelson; Uhunoma, Samson I; Edegbene, Augustine O

    2015-02-01

    The Ogba River in southern Nigeria is an important water resource for its riparian communities. This study evaluates impact of anthropogenic influences on the Ogba River using water chemistry and macroinvertebrate data sets obtained over a period of 6 months between January and June 2012. Four stations, stations 1-4, characterised by various human activities were chosen along the river. Organic wastes from domestic and industrial sources were the major point sources of pollutants. Station 2 where the municipal wastewater drains into the river had elevated values of flow velocity, BOD5, sulphate, phosphate, nitrate and sodium. Based on the canonical correspondence analysis (CCA), 5-day biochemical oxygen demand (BOD5), sulphate, nitrate and phosphate were the main factors that help to shape the macroinvertebrate assemblage structure of the Ogba River. Macroinvertebrates clustered strongly by stations than by seasons indicating that water quality differences between the stations were responsible for the observed differences in the biotic assemblage. The preponderance of naidid oligochaetes, baetid nymphs and certain tolerant dipteran taxa including chironomids and ceratopogonids at all four stations was an indication that the entire water body was stressed. The odonates were the single most abundant taxa; their dominance could be attributed to the vegetative nature of the stream, favouring odonate colonisation. Overall, the responses of macroinvertebrates to stress were reflected by the different assemblage structures recorded at the four study stations. Substrate and microhabitat obliteration and poor water quality appeared to be the factors responsible for the observed assemblage structure in the Ogba River.

  7. Changing carbonate chemistry in ocean waters surrounding coral reefs in the CMIP5 ensemble

    NASA Astrophysics Data System (ADS)

    Ricke, K.; Schneider, K.; Cao, L.; Caldeira, K.

    2012-12-01

    Coral reefs comprise some of the most biodiverse ecosystems in the world. Today they are threatened by a number of stressors, including pollution, bleaching from global warming and ocean acidification. In this study, we focus on the implications of ocean acidification for the open ocean chemistry surrounding coral reefs. We use results from 13 Earth System Models included in the Coupled Model Intercomparison Project 5 (CMIP5) to examine the changing aragonite saturations (Ωa) of open ocean waters surrounding approximately 6,000 coral reefs. These 13 Earth System Models participating in CMIP5 each have interactive ocean biogeochemistry models that output state variables including DIC, alkalinity, SST, and salinity. Variation in these values were combined with values from the GLODAP database to calculate aragonite, the form of calcium carbonate that corals use to make their skeletons. We used reef locations from ReefBase that were within one degree (in latitude or longitude) of water masses represented both in the GLODAP database and in the climate models. Carbonate chemistry calculations were performed by Dr. James C. Orr (IPSL) as part of a separate study. We find that in preindustrial times, 99.9 % of coral reefs were located in regions of the ocean with aragonite saturations of 3.5 or more. The saturation threshold for viable reef ecosystems in uncertain, but the pre-industrial distribution of water chemistry surrounding coral reefs may nevertheless provide some indication of viability. We examine the fate of coral reefs in the context of several potential aragonite saturation thresholds, i.e., when Ωa_crit equals 3, 3.25, or 3.5. We show that under a business-as-usual scenario Representative Concentration Pathway (RCP) 8.5, the specific value of Ωa_crit does not affect the long-term fate of coral reefs -- by the end of the 21st century, no coral reef considered is surrounded by water with Ωa> 3. However, under scenarios with significant CO2 emissions

  8. Impact of Water Chemistry, Pipe Material and Stagnation on the Building Plumbing Microbiome.

    PubMed

    Ji, Pan; Parks, Jeffrey; Edwards, Marc A; Pruden, Amy

    2015-01-01

    A unique microbiome establishes in the portion of the potable water distribution system within homes and other buildings (i.e., building plumbing). To examine its composition and the factors that shape it, standardized cold water plumbing rigs were deployed at the treatment plant and in the distribution system of five water utilities across the U.S. Three pipe materials (copper with lead solder, CPVC with brass fittings or copper/lead combined pipe) were compared, with 8 hour flush cycles of 10 minutes to simulate typical daily use patterns. High throughput Illumina sequencing of 16S rRNA gene amplicons was employed to profile and compare the resident bulk water bacteria and archaea. The utility, location of the pipe rig, pipe material and stagnation all had a significant influence on the plumbing microbiome composition, but the utility source water and treatment practices were dominant factors. Examination of 21 water chemistry parameters suggested that the total chlorine concentration, pH, P, SO42- and Mg were associated with the most of the variation in bulk water microbiome composition. Disinfectant type exerted a notably low-magnitude impact on microbiome composition. At two utilities using the same source water, slight differences in treatment approaches were associated with differences in rare taxa in samples. For genera containing opportunistic pathogens, Utility C samples (highest pH of 9-10) had the highest frequency of detection for Legionella spp. and lowest relative abundance of Mycobacterium spp. Data were examined across utilities to identify a true universal core, special core, and peripheral organisms to deepen insight into the physical and chemical factors that shape the building plumbing microbiome.

  9. Impact of Water Chemistry, Pipe Material and Stagnation on the Building Plumbing Microbiome

    PubMed Central

    Ji, Pan; Parks, Jeffrey; Edwards, Marc A.; Pruden, Amy

    2015-01-01

    A unique microbiome establishes in the portion of the potable water distribution system within homes and other buildings (i.e., building plumbing). To examine its composition and the factors that shape it, standardized cold water plumbing rigs were deployed at the treatment plant and in the distribution system of five water utilities across the U.S. Three pipe materials (copper with lead solder, CPVC with brass fittings or copper/lead combined pipe) were compared, with 8 hour flush cycles of 10 minutes to simulate typical daily use patterns. High throughput Illumina sequencing of 16S rRNA gene amplicons was employed to profile and compare the resident bulk water bacteria and archaea. The utility, location of the pipe rig, pipe material and stagnation all had a significant influence on the plumbing microbiome composition, but the utility source water and treatment practices were dominant factors. Examination of 21 water chemistry parameters suggested that the total chlorine concentration, pH, P, SO42- and Mg were associated with the most of the variation in bulk water microbiome composition. Disinfectant type exerted a notably low-magnitude impact on microbiome composition. At two utilities using the same source water, slight differences in treatment approaches were associated with differences in rare taxa in samples. For genera containing opportunistic pathogens, Utility C samples (highest pH of 9–10) had the highest frequency of detection for Legionella spp. and lowest relative abundance of Mycobacterium spp. Data were examined across utilities to identify a true universal core, special core, and peripheral organisms to deepen insight into the physical and chemical factors that shape the building plumbing microbiome. PMID:26495985

  10. Remote assessment of instantaneous changes in water chemistry after liming in a Nova Scotia catchment

    NASA Astrophysics Data System (ADS)

    Angelidis, Christine

    2013-04-01

    Remote assessment of instantaneous changes in water chemistry after liming in a Nova Scotia catchment ANGELIDIS, C.1, STERLING, S.1, BREEN, A.2, BIAGI, K.1., and CLAIR, T.A.1 1Dalhousie University, christine.angelidis@dal.ca, 2Bluenose Coastal Action Foundation, andrew@coastalaction.org Southwestern Nova Scotia has some of the most acidic freshwaters in North America due to its location downwind of the major emission sources in eastern Canada and the US and due to a resistant geology which offers little acid buffering capacity (Clair et al. 2007). Because of the poor buffering and regionally high runoff values, hydrological events such as snowmelt and rain storms are frequent and can cause sudden changes in water chemistry which can have devastating effects on freshwater biota due to increases in acidity and metals (Dennis and Clair in press). Clair et al. (2001) have estimated the potential frequency of acidic episodes in this region based on a number of hydrological factors, though the technology available at the time to monitor short-term changes was not dependable. Recent advances in equipment have made the assessment of the frequency and severity of acidic episodes easier and more accurate, allowing better interpretation and prediction of hydrogeochemical changes with variations in weather and deposition patterns. Here we take advantage of these recent advances to monitor water chemistry in an experimental catchment, and explore the response to catchment liming. Catchment liming is one way of mitigating the effects of acid deposition in sensitive areas. We limed a 50 ha catchment at a rate of 5 t/ha in the Gold River watershed of southwest Nova Scotia to examine the interactions between application of lime with the geological and climatological conditions of this region and acid episode frequency. In order to assess changes of episode frequency caused by liming, we established two mobile environmental monitoring platforms in the catchment: a control site

  11. Rate Theory Modeling and Simulations of Silicide Fuel at LWR Conditions

    SciTech Connect

    Miao, Yinbin; Ye, Bei; Mei, Zhigang; Hofman, Gerard; Yacout, Abdellatif

    2015-12-10

    Uranium silicide (U3Si2) fuel has higher thermal conductivity and higher uranium density, making it a promising candidate for the accident-tolerant fuel (ATF) used in light water reactors (LWRs). However, previous studies on the fuel performance of U3Si2, including both experimental and computational approaches, have been focusing on the irradiation conditions in research reactors, which usually involve low operation temperatures and high fuel burnups. Thus, it is important to examine the fuel performance of U3Si2 at typical LWR conditions so as to evaluate the feasibility of replacing conventional uranium dioxide fuel with this silicide fuel material. As in-reactor irradiation experiments involve significant time and financial cost, it is appropriate to utilize modeling tools to estimate the behavior of U3Si2 in LWRs based on all those available research reactor experimental references and state-of-the-art density functional theory (DFT) calculation capabilities at the early development stage. Hence, in this report, a comprehensive investigation of the fission gas swelling behavior of U3Si2 at LWR conditions is introduced. The modeling efforts mentioned in this report was based on the rate theory (RT) model of fission gas bubble evolution that has been successfully applied for a variety of fuel materials at devious reactor conditions. Both existing experimental data and DFT-calculated results were used for the optimization of the parameters adopted by the RT model. Meanwhile, the fuel-cladding interaction was captured by the coupling of the RT model with simplified mechanical correlations. Therefore, the swelling behavior of U3Si2 fuel and its consequent interaction with cladding in LWRs was predicted by the rate theory modeling, providing valuable information for the development of U3Si2 fuel as an accident

  12. Fracture control of ground water flow and water chemistry in a rock aquitard

    USGS Publications Warehouse

    Eaton, T.T.; Anderson, M.P.; Bradbury, K.R.

    2007-01-01

    There are few studies on the hydrogeology of sedimentary rock aquitards although they are important controls in regional ground water flow systems. We formulate and test a three-dimensional (3D) conceptual model of ground water flow and hydrochemistry in a fractured sedimentary rock aquitard to show that flow dynamics within the aquitard are more complex than previously believed. Similar conceptual models, based on regional observations and recently emerging principles of mechanical stratigraphy in heterogeneous sedimentary rocks, have previously been applied only to aquifers, but we show that they are potentially applicable to aquitards. The major elements of this conceptual model, which is based on detailed information from two sites in the Maquoketa Formation in southeastern Wisconsin, include orders of magnitude contrast between hydraulic diffusivity (K/Ss) of fractured zones and relatively intact aquitard rock matrix, laterally extensive bedding-plane fracture zones extending over distances of over 10 km, very low vertical hydraulic conductivity of thick shale-rich intervals of the aquitard, and a vertical hydraulic head profile controlled by a lateral boundary at the aquitard subcrop, where numerous surface water bodies dominate the shallow aquifer system. Results from a 3D numerical flow model based on this conceptual model are consistent with field observations, which did not fit the typical conceptual model of strictly vertical flow through an aquitard. The 3D flow through an aquitard has implications for predicting ground water flow and for planning and protecting water supplies. ?? 2007 National Ground Water Association.

  13. H02 WETLAND TREATMENT SYSTEM WATER CHEMISTRY SAMPLING AND RESULTS REPORT

    SciTech Connect

    Bach, M; Michael Serrato, M; Eric Nelson, E

    2008-02-15

    The H-02 Wetland Treatment System (Figure 1) is used to remove heavy metals (e.g., copper and zinc) from the H-Area process and storm water discharge. Routine flow enters an equalization basin by inlets on either the east (Location 1) or west end (Location 2). The west end influent constitutes 75% of the average flow into the basin which has an average residence time of approximately 3 days at low pool (i.e., 120 gal/min. through a volume of 0.5 million gallons). The water then exits via the basin outlet on the east end. Next, the water flows to a splitter box (Location 3) which evenly separates the flow between two wetland cells for a design flow of 60 gal/min. per wetland cell with a residence time in the cell of approximately 2 days. The wetland effluent is then combined (Location 4) and flows through a spillway before reaching the National Pollution Discharge Elimination System (NPDES) measurement point near Road 4. During initial operation, it was observed that the pH of the water leaving the equalization basin was elevated compared to the influent pH. Furthermore, the elevated pH remained through the wetland cells so that there was an average pH of 10 leaving the wetland cells during the daytime which exceeds the upper NPDES limit of 8.5. The purpose of the current study was to evaluate the cause of the increase in pH within the equalization basin of the H-02 Wetland Treatment System. Possible mechanisms included algal activity and inorganic chemistry interactions (e.g., interactions with the clay and/or bentonite liner). Water quality parameters were evaluated throughout the H-02 Wetland Treatment system and over time in order to determine the cause of high pH values measured in the basin and wetland. Fluctuations in dissolved oxygen (DO) and accompanying changes in pH would be expected in systems where algae are an influencing factor. An unexpected increase or decrease in the concentration of inorganic substances may indicate operational changes or an

  14. Links between climate change, water-table depth, and water chemistry in a mineralized mountain watershed

    USGS Publications Warehouse

    Manning, Andrew H.; Verplanck, Philip L.; Caine, Jonathan S.; Todd, Andrew S.

    2013-01-01

    Recent studies suggest that climate change is causing rising solute concentrations in mountain lakes and streams. These changes may be more pronounced in mineralized watersheds due to the sensitivity of sulfide weathering to changes in subsurface oxygen transport. Specific causal mechanisms linking climate change and accelerated weathering rates have been proposed, but in general remain entirely hypothetical. For mineralized watersheds, a favored hypothesis is that falling water tables caused by declining recharge rates allow an increasing volume of sulfide-bearing rock to become exposed to air, thus oxygen. Here, we test the hypothesis that falling water tables are the primary cause of an increase in metals and SO4 (100-400%) observed since 1980 in the Upper Snake River (USR), Colorado. The USR drains an alpine watershed geologically and climatologically representative of many others in mineralized areas of the western U.S. Hydrologic and chemical data collected from 2005 to 2011 in a deep monitoring well (WP1) at the top of the USR watershed are utilized. During this period, both water table depths and groundwater SO4 concentrations have generally increased in the well. A numerical model was constructed using TOUGHREACT that simulates pyrite oxidation near WP1, including groundwater flow and oxygen transport in both saturated and unsaturated zones. The modeling suggests that a falling water table could produce an increase in metals and SO4 of a magnitude similar to that observed in the USR (up to 300%). Future water table declines may produce limited increases in sulfide weathering high in the watershed because of the water table dropping below the depth of oxygen penetration, but may continue to enhance sulfide weathering lower in the watershed where water tables are shallower. Advective air (oxygen) transport in the unsaturated zone caused by seasonally variable recharge and associated water table fluctuations was found to have little influence on pyrite

  15. Robot Kinematics Identification: KUKA LWR4+ Redundant Manipulator Example

    NASA Astrophysics Data System (ADS)

    Kolyubin, Sergey; Paramonov, Leonid; Shiriaev, Anton

    2015-11-01

    This work is aimed at a comprehensive discussion of algorithms for the kinematic parameters identification of robotic manipulators. We deal with an open-loop geometric calibration task, when a full 6D robot's end-effector pose is measured. Effective solutions of such a task is of high interest in many practical applications, because it can dramatically improve key robot characteristics. On the first step, we select optimal calibration configurations. A comparative analysis of three different algorithms and two observability indexes used for numerical optimization is provided. Afterwards, using the acquired and pre-processed experimental data we identify modified Denavit-Hartenberg parameters of the manipulator. Estimates are obtained resolving original nonlinear forward kinematics relations. Finally, we compare nominal and calibrated geometric parameters and show how much deviations in these parameters affect robot positioning accuracy. To the best of our knowledge, such integrated efforts are new for the KUKA LWR4+ robot and Nikon K610 optical coordinate measuring machine (CMM), which were used in the study. Discussion of practical issues on how to organise the experiment is an additional contribution of this work. The proposed procedure is highly automated and can be implemented to improve manipulator's performance on a periodic basis.

  16. Insights Into Atmospheric Aqueous Organic Chemistry Through Controlled Experiments with Cloud Water Surrogates

    NASA Astrophysics Data System (ADS)

    Turpin, B. J.; Ramos, A.; Kirkland, J. R.; Lim, Y. B.; Seitzinger, S.

    2011-12-01

    There is considerable laboratory and field-based evidence that chemical processing in clouds and wet aerosols alters organic composition and contributes to the formation of secondary organic aerosol (SOA). Single-compound laboratory experiments have played an important role in developing aqueous-phase chemical mechanisms that aid prediction of SOA formation through multiphase chemistry. In this work we conduct similar experiments with cloud/fog water surrogates, to 1) evaluate to what extent the previously studied chemistry is observed in these more realistic atmospheric waters, and 2) to identify additional atmospherically-relevant precursors and products that require further study. We used filtered Camden and Pinelands, NJ rainwater as a surrogate for cloud water. OH radical (~10-12 M) was formed by photolysis of hydrogen peroxide and samples were analyzed in real-time by electrospray ionization mass spectroscopy (ESI-MS). Discrete samples were also analyzed by ion chromatography (IC) and ESI-MS after IC separation. All experiments were performed in duplicate. Standards of glyoxal, methylglyoxal and glycolaldehyde and their major aqueous oxidation products were also analyzed, and control experiments performed. Decreases in the ion abundance of many positive mode compounds and increases in the ion abundance of many negative mode compounds (e.g., organic acids) suggest that precursors are predominantly aldehydes, organic peroxides and/or alcohols. Real-time ESI mass spectra were consistent with the expected loss of methylglyoxal and subsequent formation of pyruvate, glyoxylate, and oxalate. New insights regarding other potential precursors and products will be provided.

  17. Oxide/Water Interfaces: How the Surface Chemistry Modifies the Electronic Energy Alignment

    NASA Astrophysics Data System (ADS)

    Sprik, Michiel

    2014-03-01

    The minimum of the d-electron conduction band of an aqueous transition metal oxide electrode is typically no more than a few 100 mV away from the standard hydrogen electrode (SHE). Because of this favourable alignment of the electronic energy levels (near) metallic transition metal oxides with partly filled d bands can be used as electrocatalysts while the compounds with finite electronic gap can be used as photocatalysts. However, because of their ionic character, transition metal-oxide surfaces also show amphiphilic acid-base activity. At low pH the basic sites are protonated and at high pH the acidic sites deprotonated creating an electrical double layer with corresponding surface potential. The alignment of the electronic energy levels, and by implication their redox activity, is therefore pH dependent. In fact, even in absence of protonic surface charge, the coordination with water molecules is already capable of shifting the electronic energy levels of the oxide by 1 eV or more. Computation of the electronic energies in transition metal oxide electrodes requires therefore a detailed modeling of their aqueous surface chemistry. The solvation energy of the proton is the common energy reference for both redox potentials on the SHE scale and acidity constants (pKa). Computation of the H+ solvation energy is therefore a key component in a unified treatment of redox and acid-base chemistry. In this talk we outline the Density Functional Theory based Molecular Dynamics (DFTMD) method we have developed for this purpose. The central tool of our approach is a method for reversible insertion of protons in the aqueous part of the DFTMD model system. As an illustration we discuss the application to the rutile TiO2/water and MnO2/water interface.

  18. Using water chemistry time series to model dissolved inorganic carbon dynamics in the western Amazon basin

    NASA Astrophysics Data System (ADS)

    Vihermaa, Leena; Waldron, Susan; Newton, Jason

    2013-04-01

    Two small streams (New Colpita and Main Trail) and two rivers (Tambopata and La Torre), in the Tambopata National Reserve, Madre de Dios, Peru, were sampled for water chemistry (conductivity, pH and dissolved oxygen) and hydrology (stage height and flow velocity). In the small streams water chemistry and hydrology variables were logged at 15 minute intervals from Feb 2011 to November 2012. Water samples were collected from all four channels during field campaigns spanning different seasons and targeting the hydrological extremes. All the samples were analysed for dissolved inorganic carbon (DIC) concentration and δ13C (sample size ranging from 77 to 172 depending on the drainage system) and a smaller subset for dissolved organic carbon (DOC) and particulate organic carbon (POC) concentrations. Strong positive relationships were found between conductivity and both DIC concentration and δ13C in the New Colpita stream and the La Torre river. In Tambopata river the trends were less clear and in the Main Trail stream there was very little change in DIC and isotopic composition. The conductivity data was used to model continuous DIC time series for the New Colpita stream. The modelled DIC data agreed well with the measurements; the concordance correlation coefficients between predicted and measured data were 0.91 and 0.87 for mM-DIC and δ13C-DIC, respectively. The predictions of δ13C-DIC were improved when calendar month was included in the model, which indicates seasonal differences in the δ13C-DIC conductivity relationship. At present, continuous DIC sampling still requires expensive instrumentation. Therefore, modelling DIC from a proxy variable which can be monitored continuously with ease and at relatively low cost, such as conductivity, provides a powerful alternative method of DIC determination.

  19. Does water chemistry limit the distribution of New Zealand mud snails in Redwood National Park?

    USGS Publications Warehouse

    Vazquez, Ryan; Ward, Darren M.; Sepulveda, Adam

    2016-01-01

    New Zealand mud snails (NZMS) are exotic mollusks present in many waterways of the western United States. In 2009, NZMS were detected in Redwood Creek in Redwood National Park, CA. Although NZMS are noted for their ability to rapidly increase in abundance and colonize new areas, after more than 5 years in Redwood Creek, their distribution remains limited to a ca. 300 m reach. Recent literature suggests that low specific conductivity and environmental calcium can limit NZMS distribution. We conducted laboratory experiments, exposing NZMS collected from Redwood Creek to both natural waters and artificial treatment solutions, to determine if low conductivity and calcium concentration limit the distribution of NZMS in Redwood National Park. For natural water exposures, we held NZMS in water from their source location (conductivity 135 μS/cm, calcium 13 mg/L) or water from four other locations in the Redwood Creek watershed encompassing a range of conductivity (77–158 μS/cm) and calcium concentration (<5–13 mg/L). For exposures in treatment solutions, we manipulated both conductivity (range 20–200 μS/cm) and calcium concentration (range <5–17.5 mg/L) in a factorial design. Response variables measured included mortality and reproductive output. Adult NZMS survived for long periods (>4 months) in the lowest conductivity waters from Redwood Creek and all but the lowest-conductivity treatment solutions, regardless of calcium concentration. However, reproductive output was very low in all natural waters and all low-calcium treatment solutions. Our results suggest that water chemistry may inhibit the spread of NZMS in Redwood National Park by reducing their reproductive output.

  20. Fracture control of ground water flow and water chemistry in a rock aquitard.

    PubMed

    Eaton, Timothy T; Anderson, Mary P; Bradbury, Kenneth R

    2007-01-01

    There are few studies on the hydrogeology of sedimentary rock aquitards although they are important controls in regional ground water flow systems. We formulate and test a three-dimensional (3D) conceptual model of ground water flow and hydrochemistry in a fractured sedimentary rock aquitard to show that flow dynamics within the aquitard are more complex than previously believed. Similar conceptual models, based on regional observations and recently emerging principles of mechanical stratigraphy in heterogeneous sedimentary rocks, have previously been applied only to aquifers, but we show that they are potentially applicable to aquitards. The major elements of this conceptual model, which is based on detailed information from two sites in the Maquoketa Formation in southeastern Wisconsin, include orders of magnitude contrast between hydraulic diffusivity (K/S(s)) of fractured zones and relatively intact aquitard rock matrix, laterally extensive bedding-plane fracture zones extending over distances of over 10 km, very low vertical hydraulic conductivity of thick shale-rich intervals of the aquitard, and a vertical hydraulic head profile controlled by a lateral boundary at the aquitard subcrop, where numerous surface water bodies dominate the shallow aquifer system. Results from a 3D numerical flow model based on this conceptual model are consistent with field observations, which did not fit the typical conceptual model of strictly vertical flow through an aquitard. The 3D flow through an aquitard has implications for predicting ground water flow and for planning and protecting water supplies.

  1. Systematic technology evaluation program for SiC/SiC composite-based accident-tolerant LWR fuel cladding and core structures: Revision 2015

    SciTech Connect

    Katoh, Yutai; Terrani, Kurt A.

    2015-08-01

    Fuels and core structures in current light water reactors (LWR’s) are vulnerable to catastrophic failure in severe accidents as unfortunately evidenced by the March 2011 Fukushima Dai-ichi Nuclear Power Plant Accident. This vulnerability is attributed primarily to the rapid oxidation kinetics of zirconium alloys in a water vapor environment at very high temperatures. Zr alloys are the primary material in LWR cores except for the fuel itself. Therefore, alternative materials with reduced oxidation kinetics as compared to zirconium alloys are sought to enable enhanced accident-tolerant fuels and cores.

  2. Element mobilization from Bakken shales as a function of water chemistry.

    PubMed

    Wang, Lin; Burns, Scott; Giammar, Daniel E; Fortner, John D

    2016-04-01

    Waters that return to the surface after injection of a hydraulic fracturing fluid for gas and oil production contain elements, including regulated metals and metalloids, which are mobilized through interactions between the fracturing fluid and the shale formation. The rate and extent of mobilization depends on the geochemistry of the formation and the chemical characteristics of the fracturing fluid. In this work, laboratory scale experiments investigated the influence of water chemistry on element mobilization from core samples taken from the Bakken formation, one of the most productive shale oil plays in the US. Fluid properties were systematically varied and evaluated with regard to pH, oxidant level, solid:water ratio, temperature, and chemical additives. Element mobilization strongly depended on solution pH and redox conditions and to a lesser extent on the temperature and solid:water ratio. The presence of oxygen and addition of hydrogen peroxide or ammonium persulfate led to pyrite oxidation, resulting in elevated sulfate concentrations. Further, depending on the mineral carbonates available to buffer the system pH, pyrite oxidation could lower the system pH and enhance the mobility of several metals and metalloids. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Wettability and surface chemistry of crystalline and amorphous forms of a poorly water soluble drug.

    PubMed

    Puri, Vibha; Dantuluri, Ajay K; Kumar, Mahesh; Karar, N; Bansal, Arvind K

    2010-05-12

    The present study compares energetics of wetting behavior of crystalline and amorphous forms of a poorly water soluble drug, celecoxib (CLB) and attempts to correlate it to their surface molecular environment. Wettability and surface free energy were determined using sessile drop contact angle technique and water vapor sorption energetics was measured by adsorption calorimetry. The surface chemistry was elucidated by X-ray photoelectron spectroscopy (XPS) and crystallographic evaluation. The two solid forms displayed distinctly different wetting with various probe liquids and in vitro dissolution media. The crystalline form surface primarily exhibited dispersive surface energy (47.3mJ/m(2)), while the amorphous form had a slightly reduced dispersive (45.2mJ/m(2)) and a small additional polar (4.8mJ/m(2)) surface energy. Calorimetric measurements, revealed the amorphous form to possess a noticeably high differential heat of absorption, suggesting hydrogen bond interactions between its polar energetic sites and water molecules. Conversely, the crystalline CLB form was found to be inert to water vapor sorption. The relatively higher surface polarity of the amorphous form could be linked to its greater oxygen-to-fluorine surface concentration ratio of 1.27 (cf. 0.62 for crystalline CLB), as determined by XPS. The crystallographic studies of the preferred cleavage plane (020) of crystalline CLB further supported its higher hydrophobicity. In conclusion, the crystalline and amorphous forms of CLB exhibited disparate surface milieu, which in turn can have implications on the surface mediated events.

  4. Review and Prioritization of Technical Issues Related to Burnup Credit for LWR Fuel

    SciTech Connect

    Parks, C V; DeHart, M D; Wagner, John C

    2000-03-13

    This report has been prepared to review relevant background information and provide technical discussion that will help initiate a PIRT (Phenomena Identification and Ranking Tables) process for use of burnup credit in light-water reactor (LWR) spent fuel storage and transport cask applications. The PIRT process will be used by the NRC Office of Nuclear Regulatory Research to help prioritize and guide a coordinated program of research and as a means to obtain input/feedback from industry and other interested parties. The review and discussion in this report are based on knowledge and experience gained from work performed in the United States and other countries. Current regulatory practice and perceived industry needs are also reviewed as a background for prioritizing technical needs that will facilitate safe practice in the use of burnup credit. Relevant physics and analysis phenomenon are identified, and an assessment of their importance to burnup credit implementation is given. Finally, phenomena that need to be better understood for effective licensing, together with technical issues that require resolution, are presented and discussed in the form of a prioritization ranking and initial draft program plan.

  5. Effect of irrigation water salinity and sodicity and water table position on water table chemistry beneath Atriplex lentiformis and Hordeum marinum

    SciTech Connect

    Browning, L.S.; Bauder, J.W.; Phelps, S.D.

    2006-04-15

    Coal bed methane (CBM) extraction in Montana and Wyoming's Powder River Basin (PRB) produces large quantities of modestly saline-sodic water. This study assessed effects of irrigation water quality and water table position on water chemistry of closed columns, simulating a perched or a shallow water table. The experiment assessed the potential salt loading in areas where shallow or perched water tables prevent leaching or where artificial drainage is not possible. Water tables were established in sand filled PVC columns at 0.38, 0.76, and1.14 m below the surface, after which columns were planted to one of three species, two halophytic Atriplex spp. and Hordeum marinum Huds. (maritime barley), a glycophyte. As results for the two Atriplex ssp. did not differ much, only results from Atriplex lentiformis (Torn) S. Wats. (big saltbush) and H. marinum are presented. Irrigation water representing one of two irrigation sources was used: Powder River (PR) (electrolytic conductivity (EC) = 0.19 Sm{sup -1}, sodium adsorption ratio (SAR) = 3.5) or CBM water (EC = 0.35 Sm-1, SAR = 10.5). Continuous irrigation with CBM and PR water led to salt loading over time, the extent being proportional to the salinity and sodicity of applied water. Water in columns planted to A. lentiformis with water tables maintained at 0.38 m depth had greater EC and SAR values than those with 0.76 and 1.14 m water table positions. Elevated EC and SAR values most likely reflect the shallow rooted nature of A. lentiformis, which resulted in enhanced ET with the water table close to the soil surface.

  6. Water Balance Defines a Threshold in Soil Chemistry at a Global Scale

    NASA Astrophysics Data System (ADS)

    Slessarev, E.; Bingham, N.; Lin, Y.; Schimel, J.; Chadwick, O.

    2015-12-01

    Carefully constrained studies in model landscapes demonstrate the existence of pedogenic thresholds, where small changes in external forcing lead to large changes in soil properties. One important threshold defines the relationship between water balance, the availability of nutrient cations, and soil pH. Across rainfall gradients, the loss of alkali and alkaline earth cations occurs abruptly at a critical water-balance. At this threshold, the removal of exchangeable base cations by leaching outstrips their production from weathering, causing a drop in soil pH. This leaching threshold has never been characterized at a global scale, in part because of the tremendous sampling effort required to overcome the confounding effects of rock chemistry, soil age, and topography outside of carefully constrained environmental gradients. We compile an extensive database of soil pH measurements to show that there is a mean global leaching threshold near an annual water balance of zero. Where evaporative demand exceeds precipitation, soil pH is buffered near values of 8.1, but where precipitation exceeds evaporative demand, soil pH rapidly collapses to values near 5.0. Deviations from the threshold can be explained in terms of climatic variability, soil age, and rock chemistry. Regions with arid climates and acid soil pH correspond to zones of intense, periodic leaching (e.g. strongly monsoonal climates), or to highly weathered continental surfaces that have permanently lost their stock of cations (e.g. Australia). Regions with humid climates and neutral soil pH correspond to young landscapes, or to soils derived from base-rich rock (e.g. the Pacific Rim volcanic belt). These results demonstrate that the leaching threshold is a dominant feature of the Earth's surface, with the potential to affect both natural and human-dominated ecosystems. For instance: the leaching threshold might impose a step-function on the terrestrial response to CO2 fertilization, the capacity of soils to

  7. Physicochemical effects of temperature and water chemistry on cohesive channel erosion

    NASA Astrophysics Data System (ADS)

    Wynn-Thompson, T.; Hoomehr, S.; Parks, O.; Eick, M.

    2013-12-01

    One potential unforeseen consequence urbanization and climate change is accelerated stream channel erosion due to increased stream temperatures and changes in stream chemistry, which affect the surface potential and hence the stability of soil colloids. Summer thunderstorms in urban watersheds can increase stream temperature more than 7 degC and the impact of global warming on average stream temperature is already evident in some stream systems. The goal of this research was to evaluate the impact of changes in stream chemistry commonly observed in urban watersheds, and expected to occur due to climate change, on the fluvial erosion of cohesive streambank soils. We hypothesized that increases in stream temperature and changes in stream pH and salt concentrations alter the surface potential of clay particles, affecting soil erodibility. We tested this hypothesis by measuring the erosion rate of two riparian soils dominated by different common phyllosilicate clays in a recirculating hydraulic flume. Two pH levels (6, 8), three water temperatures (10 degC, 20 degC, 30 degC), and two NaCl concentrations (5 mg/l, 5 g/l) were analyzed. Velocity profiles and the distance to the soil sample were measured using a Sontek Vectrino II acoustic Doppler profiler. Additionally, zetapotential was measured to determine if erosion rates were correlated to changes in clay surface potential due to varying water chemistry. Initial study results indicated significant increases in erosion rates for both clay types with decreasing pH and increasing water temperature; temperature effects were more significant than pH effects. Changes in erosion rates with salt concentration were only significant for the soil with montmorillonite clay. While the research is ongoing, these initial results could have wide-ranging implications for climate change and urban stormwater management. Assuming climate change will result in higher stream temperatures and lower stream pH, streambank erosion could

  8. Influence of aqueous chemistry on the chemical composition of fog water and interstitial aerosol in Fresno

    NASA Astrophysics Data System (ADS)

    Kim, Hwajin; Ge, Xinlei; Collier, Sonya; Xu, Jianzhong; Sun, Yele; Wang, Youliang; Herckes, Pierre; Zhang, Qi

    2015-04-01

    A measurement study was conducted in the Central Valley (Fresno) of California in January 2010, during which radiation fog events were frequently observed. Fog plays important roles in atmospheric chemistry by scavenging aerosol particles and trace gases and serving as a medium for various aqueous-phase reactions. Understanding the effects of fog on the microphysical and chemical processing of aerosol particles requires detailed information on their chemical composition. In this study, we characterized the chemical composition of fog water and interstitial aerosol particles to study the effects of fog processing on aerosol properties. Fog water samples were collected during the 2010 Fresno campaigns with a Caltech Active Strand Cloud water Collector (CASCC) while interstitial submicron aerosols were characterized in real time with an Aerodyne High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) and a scanning Mobility Particle Sizer (SMPS). The fog water samples were later analyzed using the HR-ToF-AMS, ion chromatography, and a total carbon analyzer. The chemical composition and characteristics of interstitial particles during the fog events were compared to those of dissolved inorganic and organic matter in fog waters. Compared to interstitial aerosols, fog water is composed of a higher fraction of ammonium nitrate and oxygenated organics, due to aqueous formation of secondary aerosol species as well as enhanced gas-to-particle partitioning of water soluble species under water rich conditions. Sulfate is formed most efficiently in fog water although its contribution to total dissolved mass is relatively low. The HR-ToF-AMS mass spectra of organic matter in fog water (FOM) are very similar to that of oxygenated organic aerosols (OOA) derived from positive matrix factorization (PMF) of the HR-ToF-AMS spectra of ambient aerosol (r2 = 0.96), but FOM appears to contain a large fraction of acidic functional groups than OOA. FOM is also enriched of

  9. Using initial field campaigns for optimal placement of high resolution stable water isotope and water chemistry measurements

    NASA Astrophysics Data System (ADS)

    Sahraei, Amirhossein; Kraft, Philipp; Windhorst, David; Orlowski, Natalie; Bestian, Konrad; Holly, Hartmut; Breuer, Lutz

    2017-04-01

    composition and groundwater is not reactive to the annual precipitation cycle. Consecutive runoff measurements revealed bidirectional water exchange between stream and groundwater where influent and effluent conditions occur at different stream sections during baseflow conditions. Moreover, stream water quality responds to land use with significant variation of nitrate concentration due to agricultural land use. The a priori assessment of information from various sources and methods will allow us to guide the placement of high resolution stable water isotope and water chemistry measurements. We will report on the merits and drawbacks of each approach. Results will be used to select up to 12 sampling sites for a novel self-sufficient measurement system and guide the method selection for other researchers facing a similar challenge.

  10. Water and complex organic chemistry in the cold dark cloud Barnard 5: Observations and Models

    NASA Astrophysics Data System (ADS)

    Wirström, Eva; Charnley, Steven B.; Taquet, Vianney; Persson, Carina M.

    2015-08-01

    Studies of complex organic molecule (COM) formation have traditionally been focused on hot cores in regions of massive star formation, where chemistry is driven by the elevated temperatures - evaporating ices and allowing for endothermic reactions in the gas-phase. As more sensitive instruments have become available, the types of objects known to harbour COMs like acetaldehyde (CH3CHO), dimethyl ether (CH3OCH3), methyl formate (CH3OCHO), and ketene (CH2CO) have expanded to include low mass protostars and, recently, even pre-stellar cores. We here report on the first in a new category of objects harbouring COMs: the cold dark cloud Barnard 5 where non-thermal ice desorption induce complex organic chemistry entirely unrelated to local star-formation.Methanol, which only forms efficiently on the surfaces of dust grains, provide evidence of efficient non-thermal desorption of ices in the form of prominent emission peaks offset from protostellar activity and high density tracers in cold molecular clouds. A study with Herschel targeting such methanol emission peaks resulted in the first ever detection of gas-phase water offset from protostellar activity in a dark cloud, at the so called methanol hotspot in Barnard 5.To model the effect a transient injection of ices into the gas-phase has on the chemistry of a cold, dark cloud we have included gas-grain interactions in an existing gas-phase chemical model and connected it to a chemical reaction network updated and expanded to include the formation and destruction paths of the most common COMs. Results from this model will be presented.Ground-based follow-up studies toward the methanol hotspot in B5 have resulted in the detection of a number of COMs, including CH2CO, CH3CHO, CH3OCH3, and CH3OCHO, as well as deuterated methanol (CH2DOH). Observations have also confirmed that COM emission is extended and not localised to a core structure. The implications of these observational and theoretical studies of B5 will be discussed

  11. Effect of water chemistry upsets on the dynamics of corrective reagent dosing systems at thermal power stations

    NASA Astrophysics Data System (ADS)

    Voronov, V. N.; Yegoshina, O. V.; Bolshakova, N. A.; Yarovoi, V. O.; Latt, Aie Min

    2016-12-01

    Typical disturbances in the dynamics of a corrective reagent dosing system under unsteady-state conditions during the unsatisfactory operation of a chemical control system with some water chemistry upsets at thermal and nuclear power stations are considered. An experimental setup representing a physical model for the water chemistry control system is described. The two disturbances, which are most frequently encountered in water chemistry control practice, such as a breakdown or shutdown of temperature compensation during pH measurement and an increase in the heat-transfer fluid flow rate, have been modeled in the process of study. The study of the effect produced by the response characteristics of chemical control analyzers on the operation of a reagent dosing system under unsteady-state conditions is important for the operative control of a water chemistry regime state. The effect of temperature compensation during pH measurement on the dynamics of an ammonia-dosing system in the manual and automatic cycle chemistry control modes has been studied. It has been demonstrated that the reading settling time of a pH meter in the manual ammonia- dosing mode grows with a breakdown in temperature compensation and a simultaneous increase in the temperature of a heat-transfer fluid sample. To improve the efficiency of water chemistry control, some systems for the quality control of a heat-transfer fluid by a chemical parameter with the obligatory compensation of a disturbance in its flow rate have been proposed for use. Experimental results will possibly differ from industrial data due to a great length of sampling lines. For this reason, corrective reagent dosing systems must be adapted to the conditions of a certain power-generating unit in the process of their implementation.

  12. Water Chemistry Control System for Recovery of Damaged and Degraded Spent Fuel

    SciTech Connect

    Sindelar, R.; Fisher, D.; Thomas, J.

    2011-02-18

    The International Atomic Energy Agency (IAEA) and the government of Serbia have led the project cosponsored by the U.S, Russia, European Commission, and others to repackage and repatriate approximately 8000 spent fuel elements from the RA reactor fuel storage basins at the VIN?A Institute of Nuclear Sciences to Russia for reprocessing. The repackaging and transportation activities were implemented by a Russian consortium which includes the Sosny Company, Tekhsnabeksport (TENEX) and Mayak Production Association. High activity of the water of the fuel storage basin posed serious risk and challenges to the fuel removal from storage containers and repackaging for transportation. The risk centered on personnel exposure, even above the basin water, due to the high water activity levels caused by Cs-137 leached from fuel elements with failed cladding. A team of engineers from the U.S. DOE-NNSA's Global Threat Reduction Initiative, the Vinca Institute, and the IAEA performed the design, development, and deployment of a compact underwater water chemistry control system (WCCS) to remove the Cs-137 from the basin water and enable personnel safety above the basin water for repackaging operations. Key elements of the WCCS system included filters, multiple columns containing an inorganic sorbent, submersible pumps and flow meters. All system components were designed to be remotely serviceable and replaceable. The system was assembled and successfully deployed at the Vinca basin to support the fuel removal and repackaging activities. Following the successful operations, the Cs-137 is now safely contained and consolidated on the zeolite sorbent used in the columns of the WCCS, and the fuel has been removed from the basins. This paper reviews the functional requirements, design, and deployment of the WCCS.

  13. Environmental water chemistry and possible correlation with Kaschin-Beck Disease (KBD) in northwestern Sichuan, China.

    PubMed

    Shi, Zeming; Pan, Pujing; Feng, Yanwei; Kan, Zezhong; Li, Zhonghui; Wei, Fei

    2017-02-01

    During the past several decades, etiological and geochemical studies tend to link the Kaschin-Beck Disease (KBD) to the deficiency of some specific trace elements (e.g., selenium and iodine) in the environment; however the link has been proven inconclusive. In this work, we have investigated the relationship between KBD and the environment in a broader scope by examining comprehensively the chemistry of the surface waters in northwestern Sichuan, China, in relation to the KBD prevalence. The surface waters in the study area were found to be near neutral to slightly alkaline (pH6.70 to 8.85 with a mean of 7.91) and mostly soft (total hardness 35.2 to 314.3mg/L, mean 118.8mg/L) with low salinity (total dissolved solids (TDS) 44.5mg/L to 376.6mg/L, mean 146.6mg/L). The waters were dominated by cations Ca(2+) and Mg(2+) and anion HCO3(-); whereas the alkali metal ions K(+) and Na(+) and the anions Cl(-) and S04(2-) were relatively scarce. Spatially, the hardness/salinity of the surface waters exhibited a characteristic of being lower towards the center of the study area where most severe KBD endemic has been observed. Even though it is not conclusive at this stage, a correlation between KBD prevalence and the salinity/hardness of the surface waters of an area has been demonstrated. As a postulate, the long-term consumption of such low salinity waters may lead to a deficiency of some essential elements such as Ca, Mg, Se and I in humans, which may be a factor in inducing KBD. However, other factors such as high altitude and cold climate, poor nutrition and sanitary conditions may play an important role in the disease endemic.

  14. Natural and anthropogenic sources and processes affecting water chemistry in two South Korean streams.

    PubMed

    Shin, Woo-Jin; Ryu, Jong-Sik; Mayer, Bernhard; Lee, Kwang-Sik; Lee, Sin-Woo

    2014-07-01

    Acid mine drainage (AMD) in a watershed provides potential sources of pollutants for surface and subsurface waters that can deteriorate water quality. Between March and early August 2011, water samples were collected from two streams in South Korea, one dominantly draining a watershed with carbonate bedrock affected by coal mines and another draining a watershed with silicate bedrock and a relatively undisturbed catchment area. The objective of the study was to identify the sources and processes controlling water chemistry, which was dependent on bedrock and land use. In the Odae stream (OS), the stream in the silicate-dominated catchment, Ca, Na, and HCO3 were the dominant ions and total dissolved solids (TDS) was low (26.1-165 mg/L). In the Jijang stream (JS), in the carbonate-dominated watershed, TDS (224-434 mg/L) and ion concentrations were typically higher, and Ca and SO4 were the dominant ions due to carbonate weathering and oxidation of pyrite exposed at coal mines. Dual isotopic compositions of sulfate (δ(34)SSO4 and δ(18)OSO4) verified that the SO4 in JS is derived mainly from sulfide mineral oxidation in coal mines. Cl in JS was highest upstream and decreased progressively downstream, which implies that pollutants from recreational facilities in the uppermost part of the catchment are the major source governing Cl concentrations within the discharge basin. Dual isotopic compositions of nitrate (δ(15)NNO3 and δ(18)ONO3) indicated that NO3 in JS is attributable to nitrification of soil organic matter but that NO3 in OS is derived mostly from manure. Additionally, the contributions of potential anthropogenic sources to the two streams were estimated in more detail by using a plot of δ(34)SSO4 and δ(15)NNO3. This study suggests that the dual isotope approach for sulfate and nitrate is an excellent additional tool for elucidating the sources and processes controlling the water chemistry of streams draining watersheds having different lithologies and

  15. Urban and Suburban Influences on Water Chemistry in Washington DC: Impervious Surfaces and Urban Stream Syndrome

    NASA Astrophysics Data System (ADS)

    MacAvoy, S. E.; Petersen, E.

    2015-12-01

    Among the challenges facing urban rivers are water stormwater runoff problems and changing water chemistry, not only from air and water pollution sources, but also from altered geology with the development of "urban karst". Seventy five percent of the Anacostia River in Washington, D.C. is urban or impervious. The Anacostia River experiences environmental challenges similar to those of other urban industrial rivers (heavy metal, PCB and PAH contamination). It also has Ca/Sr ratios above 200, and Na concentrations higher than Ca, and elevated ionic strength, all associated with extended chemical interaction with concrete. While these chemical characteristics have been documented in the urban areas within DC, they have not been examined in the largely suburban/mixed development tributaries of the Anacostia. Here we examine the base-flow geochemistry of the Anacostia River and its suburban tributaries (6 locations) over a year (November 2014- August 2015), concentrating on the following water chemistry variables: pH, hardness, SAR, alkalinity, Ca, Mg, Na, K, Fe, Mn, Zn, Al, Ba, Ni, total P, S, Sr, NO3-, NH4+, PO43-. NO3- and NH4+ were generally lowest in at all sites in January, but rose to between 0.5 and 2.4 mg/L in June, with highest NO3- concentrations in suburban areas. Na and Cl concentrations were 5x higher in suburban areas than urban areas during the winter months. Ca/Sr concentration ratios, were between 120 and 200 for suburban sites but increased as the sites became more urban (to a high of 240 for the most urban site). These trends have been observed in other urban streams, and correlate with percent impervious area. The data follow patterns expected for "urban stream syndrome" and dissolution of concrete. Suburban areas, with their relatively small streams, show greater winter salting effects than more urban areas down stream. Suburban areas also show higher NO3- (and occasionally higher NH4+) than urban areas except in winter. The data presented here

  16. Water-soluble NHC-Cu catalysts: applications in click chemistry, bioconjugation and mechanistic analysis.

    PubMed

    Díaz Velázquez, Heriberto; Ruiz García, Yara; Vandichel, Matthias; Madder, Annemieke; Verpoort, Francis

    2014-12-14

    Copper(I)-catalyzed 1,3-dipolar cycloaddition of azides and terminal alkynes (CuAAC), better known as "click" reaction, has triggered the use of 1,2,3-triazoles in bioconjugation, drug discovery, materials science and combinatorial chemistry. Here we report a new series of water-soluble catalysts based on N-heterocyclic carbene (NHC)-Cu complexes which are additionally functionalized with a sulfonate group. The complexes show superior activity towards CuAAC reactions and display a high versatility, enabling the production of triazoles with different substitution patterns. Additionally, successful application of these complexes in bioconjugation using unprotected peptides acting as DNA binding domains was achieved for the first time. Mechanistic insight into the reaction mechanism is obtained by means of state-of-the-art first principles calculations.

  17. Water chemistry and isotope data from a five year monitoring programme of Bunker Cave, NW Germany

    NASA Astrophysics Data System (ADS)

    Riechelmann, S.; Schröder-Ritzrau, A.; Spötl, C.; Riechelmann, D. F. C.; Richter, D. K.; Immenhauser, A.

    2012-04-01

    Water chemistry and isotope data from a five year monitoring programme of Bunker Cave, NW Germany Sylvia Riechelmann (1), Andrea Schröder-Ritzrau (2), Christoph Spötl (3), Dana F.C. Riechelmann (4), Detlev K. Richter (1), Adrian Immenhauser (1) (1) Ruhr-University Bochum, Institute for Geology, Mineralogy and Geophysics, Universitätsstraße 150, D-44801 Bochum, Germany (2) Heidelberg Academy of Sciences, Im Neuenheimer Feld 229, D-69120 Heidelberg, Germany (3) Leopold-Franzens-University Innsbruck, Institute for Geology and Palaeontology, Innrain 52, A-6020 Innsbruck, Austria (4) Johannes Gutenberg-University Mainz, Institute of Geography, Johann-Joachim-Becher-Weg 21, D-55128 Mainz, Germany Monitoring of cave environments is essential to understand the processes taking place in the soil, karst and cave zone and the interpretation of speleothem archives is increasingly based on monitoring data. A five year monitoring programme of Bunker Cave (NW Germany) included monthly sampling of rain, soil and drip water. The delta18O ratios of the drip waters reflect the mean annual delta18O composition of rain water. The weak seasonal pattern in drip water delta18O composition is overlain by a trend to increasing values (approximately 0.3‰ in the monitoring period between 2007 and 2011). Up to the year 2009, rain water delta18O values show an increasing trend. In 2010, the lowest yearly mean delta18O ratio of rain water (-9.20‰) was observed, probably due to cool summer air temperatures and significant amounts of snow fall during winter months 2010. A decrease of the drip water delta18O in the future will expectedly allow to stack both data series and to identify time delay between rain water and drip water series and allow for the quantification of the approximate transfer time of rain water from soil surface into the cave. The Mg2+-concentration of one drip site correlates positively with drip rate. High Mg2+-concentrations occur especially after dry periods (low

  18. Stream Water and Soil Water Chemistry Following the Table Mountain Wildfire, Washington

    NASA Astrophysics Data System (ADS)

    Roccanova, V. J.; Gazis, C. A.

    2013-12-01

    Severe wildfire occurrence in the Western United States increased throughout the 20th century and has continued to increase into the 21st century. Global climate change resulting from natural and anthropogenic sources is considered a contributor to this increase in wildfire severity. Fire suppression techniques developed in the early 20th century are also a factor in increased severe wildfire occurrence as they augment available fuel loads. Biomass burning releases nutrients that are held within trees and plants. Nitrogen, phosphorous, and calcium levels have been documented as increasing in stream waters as a result of wildfire. As severe wildfire occurrence increases, so does the likelihood that stream, and to a lesser extent groundwater, will be loaded with nutrients and sediments as a result of wildfire activity. Increased nutrient loads can cause algal blooms that deplete streams of oxygen, important to aquatic plants and animals that reside in these streams. These changes in water quality can also affect humans who depend on these streams for irrigation and drinking water purposes. The Table Mountain wildfire in Washington State was started by a lightning strike that occurred at approximately 8:00 PM on Saturday September 8th, 2012. The fire burned for approximately one month and was declared to be 100% contained on Friday October 5th, 2012. Over this period the fire burned a total of 171 square kilometers of forest. In this study multiple stream and soil water samples were collected from three types of area in the winter through summer following the fire: severely burned, moderately burned, and unburned. All areas sampled have similar bedrock and vegetation cover. These samples were analyzed for major ions and trace element concentrations. Select samples will also be analyzed for strontium isotope ratios. The results of these geochemical analyses will be presented. Because calcium and strontium have similar properties, their concentrations can be combined

  19. Influence of microbial photosynthesis on tufa stromatolite formation and ambient water chemistry, SW Japan

    NASA Astrophysics Data System (ADS)

    Shiraishi, Fumito; Okumura, Tomoyo; Takahashi, Yoshio; Kano, Akihiro

    2010-09-01

    Photosynthetic influences on tufa stromatolite formation and ambient water chemistry were investigated at two well-studied streams depositing tufa in Southwestern Japan (Shirokawa and Shimokuraida). The tufa stromatolites in both streams are composed of fine-grained calcite crystals showing annual lamination, and colonized by a number of filamentous cyanobacteria as well as non-phototrophic bacteria. Microelectrode measurements of pH, O 2, and Ca 2+ near the stromatolite surface (the diffusive boundary layer; DBL) revealed that the investigated tufa stromatolites are formed by photosynthesis-induced CaCO 3 precipitation (PCP): cyanobacterial photosynthesis induces calcite precipitation under light conditions, while respiration of cyanobacteria and non-phototrophic bacteria inhibits precipitation in the dark. The bulk water chemistry at the lower sites of the investigated streams showed the daytime decreases of Ca 2+ concentration and alkalinity that was expected for significant influence of PCP, while the other expected change, increased pH, was not observed. In order to examine this discrepancy, a novel approach using semi- in situ microelectrode measurements was applied to perform precise quantitative calculations. The calculation results demonstrated that the observed Ca 2+ concentration and alkalinity decreases were caused by PCP, and that the concomitant pH increase was expected to be under the detection level of a conventional pH meter. Although the amount of PCP is supposed to be significantly affected by light intensity, observations in Shimokuraida revealed that the amount of PCP on cloudy day nonetheless accounted for about 80% of that on sunny day. Despite the significant role of PCP for tufa stromatolite formation, PCP accounted for only about 10% of the precipitated calcite in the investigated streams, which indicates that tufa stromatolites, the characteristic deposits in the streams, are responsible for only a small portion of calcite precipitation

  20. Stream water chemistry in a gabbro/granite watershed, Quabbin reservation, central Massachusetts

    SciTech Connect

    Reid, J.B. Jr.; Gallant, J.; Christensen, C.; Mengason, M. . School of Natural Science)

    1993-03-01

    While monitoring pH-alkalinity relationships in tributaries of the Quabbin Reservoir, the authors have discovered an anomalous brook whose waters become progressively more acidic downstream. The watershed's bedrock is roughly half Prescott hornblende gabbro and half Cooleyville granitic gneiss with the contact crossing the watershed diagonally; gabbroic bedrock dominates the stream's upper reaches. Outcrop density and topography suggest relatively thin till cover (< [approximately]2m). All parts of the stream get some contribution from both bedrock types, through gabbro contribution diminishes smoothly downstream. Springs in gabbro (pH [approximately]7, alk 20--30mg/1, cond [approximately]50[mu]mho) and in granite (pH [approximately]5, alk 2--6 mg/1, cond [approximately]15[mu]mho) retain these characteristics through dry and wet seasons; the stream's response to high rain events is more complex and can be used to estimate where surface water and groundwater each make their greatest contributions. Each point along the brook can be assigned a value of %gabbro characterizing the bedrock proportions in the watershed upstream of it; plots of major cations, alkalinity and conductivity vs. %gabbro show strong positive correlation. Two-week leaching experiments (initial pH = 4) with A, B and C soil horizons from both sides of the contact show greatest rises (to pH = 5.5) in gabbro soils distant from the contact, and progressively smaller increases crossing the contact to granite soils (pH rises to 4.5). The data suggest that bedrock and soil chemistry are primarily responsible for stream chemistry; topography and residence time here play secondary roles.

  1. Vertical Gradients in Water Chemistry and Age in the Southern High Plains Aquifer, Texas, 2002

    USGS Publications Warehouse

    McMahon, P.B.; Böhlke, J.K.; Lehman, T.M.

    2004-01-01

    The southern High Plains aquifer is the primary source of water used for domestic, industrial, and irrigation purposes in parts of New Mexico and Texas. Despite the aquifer's importance to the overall economy of the southern High Plains, fundamental ground-water characteristics, such as vertical gradients in water chemistry and age, remain poorly defined. As part of the U.S. Geological Survey's National Water-Quality Assessment Program, water samples from nested, short-screen monitoring wells installed in the southern High Plains aquifer at two locations (Castro and Hale Counties, Texas) were analyzed for field parameters, major ions, nutrients, trace elements, dissolved organic carbon, pesticides, stable and radioactive isotopes, and dissolved gases to evaluate vertical gradients in water chemistry and age in the aquifer. Tritium measurements indicate that recent (post-1953) recharge was present near the water table and that deeper water was recharged before 1953. Concentrations of dissolved oxygen were largest (2.6 to 5.6 milligrams per liter) at the water table and decreased with depth below the water table. The smallest concentrations were less than 0.5 milligram per liter. The largest major-ion concentrations generally were detected at the water table because of the effects of overlying agricultural activities, as indicated by postbomb tritium concentrations and elevated nitrate and pesticide concentrations at the water table. Below the zone of agricultural influence, major-ion concentrations exhibited small increases with depth and distance along flow paths because of rock/water interactions and mixing with water from the underlying aquifer in rocks of Cretaceous age. The concentration increases primarily were accounted for by dissolved sodium, bicarbonate, chloride, and sulfate. Nitrite plus nitrate concentrations at the water table were 2.0 to 6.1 milligrams per liter as nitrogen, and concentrations substantially decreased with depth in the aquifer to a

  2. Multivariate Statistical Analysis of Water Chemistry in Evaluating the Origin of Contamination in Many Devils Wash, Shiprock, New Mexico

    SciTech Connect

    None, None

    2012-12-31

    This report evaluates the chemistry of seep water occurring in three desert drainages near Shiprock, New Mexico: Many Devils Wash, Salt Creek Wash, and Eagle Nest Arroyo. Through the use of geochemical plotting tools and multivariate statistical analysis techniques, analytical results of samples collected from the three drainages are compared with the groundwater chemistry at a former uranium mill in the Shiprock area (the Shiprock site), managed by the U.S. Department of Energy Office of Legacy Management. The objective of this study was to determine, based on the water chemistry of the samples, if statistically significant patterns or groupings are apparent between the sample populations and, if so, whether there are any reasonable explanations for those groupings.

  3. Pesticides in Drinking Water: Project-Based Learning within the Introductory Chemistry Curriculum

    NASA Astrophysics Data System (ADS)

    O'Hara, Patricia B.; Sanborn, Jon A.; Howard, Meredith

    1999-12-01

    Public concern has been expressed regarding low-level contamination of public drinking water with "xenoestrogens", which are manmade compounds that act like the growth stimulant, estrogen. A new introductory chemistry module is described, which has as its central theme the measurement of trace levels of these xenoestrogens in the form of pesticides in the Town of Amherst's public drinking water. After a basic introduction to sample handling and measurement of pH, temperature, and conductivity, the students travel in small groups to several sites to collect water and perform preliminary characterization of their samples. In subsequent weeks, they learn to perform various analytical techniques such as solid-phase extraction, GC-MS, ELISA, and absorption spectroscopy to measure the levels of the pesticides DDT, DDD, DDE, methoxychlor, and endosulfan, all of which are potent estrogen mimics. In addition to individual lab reports, students are asked to combine their results and analyze the data set to determine the mean concentration and the statistical significance. Finally, they use molecular modeling to explore the three-dimensional structure of three pesticide families and compare these structures to the steroid hormones whose actions they are purported to mimic.

  4. Reactive nitrogen chemistry in aerosol water as a source of sulfate during haze events in China

    PubMed Central

    Cheng, Yafang; Zheng, Guangjie; Wei, Chao; Mu, Qing; Zheng, Bo; Wang, Zhibin; Gao, Meng; Zhang, Qiang; He, Kebin; Carmichael, Gregory; Pöschl, Ulrich; Su, Hang

    2016-01-01

    Fine-particle pollution associated with winter haze threatens the health of more than 400 million people in the North China Plain. Sulfate is a major component of fine haze particles. Record sulfate concentrations of up to ~300 μg m−3 were observed during the January 2013 winter haze event in Beijing. State-of-the-art air quality models that rely on sulfate production mechanisms requiring photochemical oxidants cannot predict these high levels because of the weak photochemistry activity during haze events. We find that the missing source of sulfate and particulate matter can be explained by reactive nitrogen chemistry in aerosol water. The aerosol water serves as a reactor, where the alkaline aerosol components trap SO2, which is oxidized by NO2 to form sulfate, whereby high reaction rates are sustained by the high neutralizing capacity of the atmosphere in northern China. This mechanism is self-amplifying because higher aerosol mass concentration corresponds to higher aerosol water content, leading to faster sulfate production and more severe haze pollution. PMID:28028539

  5. Photon and Water Mediated Sulfur Oxide and Acid Chemistry in the Atmosphere of Venus

    NASA Astrophysics Data System (ADS)

    Kroll, Jay A.; Vaida, Veronica

    2014-06-01

    Sulfur compounds have been observed in the atmospheres of a number of planetary bodies in our solar system including Venus, Earth, Mars, Io, Europa, and Callisto. The global cloud cover on Venus located at an altitude between 50 and 80 kilometers is composed primarily of sulfuric acid (H_2SO_4) and water. Planetary photochemical models have attempted to explain observations of sulfuric acid and sulfur oxides with significant discrepancies remaining between models and observation. In particular, high SO_2 mixing ratios are observed above 90 km which exceed model predictions by orders of magnitude. Work recently done in the Vaida lab has shown red light can drive photochemistry through overtone pumping for acids like H_2SO_4 and has been successful in explaining much of the sulfur chemistry in Earth's atmosphere. Water can have a number of interesting effects such as catalysis, suppression, and anti-catalysis of thermal and photochemical processes. We investigate the role of water complexes in the hydration of sulfur oxides and dehydration of sulfur acids and present spectroscopic studies to document such effects. We investigate these reactions using FTIR and UV/Vis spectroscopy and will report on our findings.

  6. The evolution of thermal structure and water chemistry in Lake Nyos

    USGS Publications Warehouse

    Kling, G.W.; Tuttle, M.L.; Evans, William C.

    1989-01-01

    We collected a time series of physical and chemical data to gain a better understanding of the dynamics of Lake Nyos. Measurements of water and gas chemistry, and temperature made during January, March, and May 1987 are compared to data taken in September 1986 just after the initial CO2 gas release. There is no pattern of change in overall heat content of the lake, although heat input to bottom waters (185-208 m) has occurred at a rate of 1600 mW m-2. This increase in heat content translates to a change from 23.38 to 24.12??C at 200 m and can be explained by geothermal heat flow and addition of thermal spring water. Concentrations of Ca2+, Mg2+, Na+, K+, Fe2+ and alkalinity have increased only in bottom waters. In situ lake processes such as sulfate and iron reduction are unable to account for the changes in alkalinity. Observed chemical changes are consistent with a scenario where slightly thermal soda water is being input to the bottom of the lake. Measurements of pCO2 at depth ranged from 18 to 28% of saturation and exhibited horizontal variability. Overall recharge of CO2 in bottom waters is negligible. Mainly because of increasing ion concentrations in bottom water, total stability of the water column increased 33% from 48,800 J m-2 in September 1986 to 64,700 J m-2 in May 1987. As long as CO2 concentrations remain the same, this level of stability is higher than could be disrupted by common limnologic or meteorologic processes. There is thermal and chemical evidence that a buildup of dissolved iron and CO2 in bottom waters must have preceded the August 1986 gas release. In addition, a survey of all crater lakes in Cameroon indicates that only Lakes Nyos and Monoun contain high concentrations of dissolved iron and CO2. Thus there is a low probability of any other Cameroonian lake releasing a substantial volume of CO2. ?? 1989.

  7. Long-term fluctuations in water chemistry for streams located in different physiographic provinces of Alabama

    SciTech Connect

    Donahoe, R.J. . Dept. of Geology)

    1993-03-01

    The compositional variation of stream water in nine different watersheds has been the subject of a three year study. Three of the nine streams are underlain by sandstone and are located in the Plateau physiographic province of Alabama, three watersheds have phyllite bedrock and are located in the AL Piedmont, and three streams draining carbonate units are located in the Valley and Ridge structural province of AL. These streams all have very similar climatic conditions, and were selected to provide three replicate data sets for streams closely matched in structural setting and bedrock type and to allow comparison between streams in the three different structural settings and bedrock types. Between 24-36 monthly stream water samples were collected for each watershed over the study period and analyzed for cations, anions, pH, and alkalinity. All streams show seasonal variations in major cation and anion concentrations. In general, major cation concentration minima occurred in Winter 1989-90 and late Spring/early Summer 1991 for all streams. This suggests dilution/evaporation as dominant controls on stream water major element chemistry. Comparison of chemical trends with precipitation records and stream stage data is underway to test this hypothesis. Great variation in stream water anion concentration occurs within the large-scale seasonal trends for all streams. These variations are primarily the result of biologic activity. Differences in major element concentration trends exist between streams within a particular bedrock type. Element speciation and mineral saturation indices were calculated using the computerized chemical equilibrium code WATEQ4F. Plots of mineral saturation indices with season show that all stream waters are essentially saturated with quartz, undersaturated with primary silicate minerals, and supersaturated with most clay minerals and ferric iron oxides. Further, carbonate streams are undersaturated with calcite and dolomite.

  8. Trends in ostracod distribution and water chemistry in subarctic Canada: Churchill (Manitoba) lakes and ponds revisited

    NASA Astrophysics Data System (ADS)

    Viehberg, F. A.; Côté, G.; Pienitz, R.

    2009-04-01

    Ecosystems change in response to factors such as climate variability, invasions, and natural hazards over a short period of time (IPCC 2007). The individual organism has to react to complete its life cycle and eventually to reproduce successfully. Under extreme conditions the survival of the total population depends thoroughly on the genetic diversity/potential and thus the ability to expand its biogeographical range or to run extinct. The knowledge of the specific plasticity in time is essential to interpret signals of biological proxies in palaeo records. We investigated 13 lakes/ponds in the surrounding of the Churchill Northern Studies Centre (CNSC; 58° 43.989'N, 93° 49.219'W), Churchill, Canada in 1997. 9 years later we revisited the same localities in 2006. In addition, faunistic data of microcrustaceans in the local study area is available from the late 80's (Havel et al 1990 a, b). and further instrumental climate records from Churchill (Manitoba, Canada) are daily filed since 1943 by Environment Canada. Thus we were able to pinpoint local warming trends and changes in the water chemistry from our short term records in the subarctic study area. The microcrustacean fauna change consecutively. e.g., freshwater ostracods adopted to short open water periods during the summer, strong variations of water temperatures in the shallow waters and mostly low ionic contents of the host waters are not present in the current record. References: Havel, J.E., Hebert, P.D.N. and Delorme, L.D., 1990a. Genetics of sexual Ostracoda from a low Arctic site. Journal of Evolutionary Biology, 3: 65-84. Havel, J.E., Hebert, P.D.N. and Delorme, L.D., 1990b. Genotypic diversity of asexual Ostracoda from a low Arctic site. Journal of Evolutionary Biology, 3: 391-410.

  9. Are fragment-based quantum chemistry methods applicable to medium-sized water clusters?

    PubMed

    Yuan, Dandan; Shen, Xiaoling; Li, Wei; Li, Shuhua

    2016-06-28

    Fragment-based quantum chemistry methods are either based on the many-body expansion or the inclusion-exclusion principle. To compare the applicability of these two categories of methods, we have systematically evaluated the performance of the generalized energy based fragmentation (GEBF) method (J. Phys. Chem. A, 2007, 111, 2193) and the electrostatically embedded many-body (EE-MB) method (J. Chem. Theory Comput., 2007, 3, 46) for medium-sized water clusters (H2O)n (n = 10, 20, 30). Our calculations demonstrate that the GEBF method provides uniformly accurate ground-state energies for 10 low-energy isomers of three water clusters under study at a series of theory levels, while the EE-MB method (with one water molecule as a fragment and without using the cutoff distance) shows a poor convergence for (H2O)20 and (H2O)30 when the basis set contains diffuse functions. Our analysis shows that the neglect of the basis set superposition error for each subsystem has little effect on the accuracy of the GEBF method, but leads to much less accurate results for the EE-MB method. The accuracy of the EE-MB method can be dramatically improved by using an appropriate cutoff distance and using two water molecules as a fragment. For (H2O)30, the average deviation of the EE-MB method truncated up to the three-body level calculated using this strategy (relative to the conventional energies) is about 0.003 hartree at the M06-2X/6-311++G** level, while the deviation of the GEBF method with a similar computational cost is less than 0.001 hartree. The GEBF method is demonstrated to be applicable for electronic structure calculations of water clusters at any basis set.

  10. Survey of LWR environmental control technology performance and cost

    SciTech Connect

    Heeb, C.M.; Aaberg, R.L.; Cole, B.M.; Engel, R.L.; Kennedy, W.E. Jr.; Lewallen, M.A.

    1980-03-01

    This study attempts to establish a ranking for species that are routinely released to the environment for a projected nuclear power growth scenario. Unlike comparisons made to existing standards, which are subject to frequent revision, the ranking of releases can be used to form a more logical basis for identifying the areas where further development of control technology could be required. This report describes projections of releases for several fuel cycle scenarios, identifies areas where alternative control technologies may be implemented, and discusses the available alternative control technologies. The release factors were used in a computer code system called ENFORM, which calculates the annual release of any species from any part of the LWR nuclear fuel cycle given a projection of installed nuclear generation capacity. This survey of fuel cycle releases was performed for three reprocessing scenarios (stowaway, reprocessing without recycle of Pu and reprocessing with full recycle of U and Pu) for a 100-year period beginning in 1977. The radioactivity releases were ranked on the basis of a relative ranking factor. The relative ranking factor is based on the 100-year summation of the 50-year population dose commitment from an annual release of radioactive effluents. The nonradioactive releases were ranked on the basis of dilution factor. The twenty highest ranking radioactive releases were identified and each of these was analyzed in terms of the basis for calculating the release and a description of the currently employed control method. Alternative control technology is then discussed, along with the available capital and operating cost figures for alternative control methods.

  11. The effect of dissolution of volcanic glass on the water chemistry in a tuffaceous aquifer, Rainier Mesa, Nevada

    USGS Publications Warehouse

    White, Art F.; Claassen, H.C.; Benson, Larry V.

    1980-01-01

    Geochemistry of ground water associated with the Tertiary tuffs within Rainier Mesa, southern Nevada, was investigated to determine the relative importance of glass dissolution in controlling water chemistry. Water samples were obtained both from interstitial pores in core sections and from free-flowing fractures. Cation com- positions showed that calcium and magnesium decreased as a function of depth in the mesa, as sodium increased. The maximum effect occurs within alteration zones containing clinoptilolite and montmorillonite, suggesting these minerals effectively remove bivalent cations from the system. Comparisons are made between compositions of ground waters found within Rainier Mesa that apparently have not reacted with secondary minerals and compositions of waters produced by experimental dissolution of vitric and crystalline tufts which comprise the principal aquifers in the area. The two tuff phases have the same bulk chemistry but produce aqueous solutions of different chemistry. Rapid parabolic dissolution of sodium and silica from, and the retention of, potassium within the vitric phase verify previous predictions concerning water compositions associated with vitric volcanic rocks. Parabolic dissolution of the crystalline phase results in solutions high in calcium and magnesium and low in silica. Extrapolation of the parabolic dissolution mechanism for the vitric tuff to long times successfully reproduces, at com- parable pH, cation ratios existing in Rainier Mesa ground water. Comparison of mass- transfer rates of the vitric and crystalline tuffs indicates that the apparent higher glass-surface to aqueous-volume ratio associated with the vitric rocks may account for dominance of the glass reaction.

  12. Mineralogy and geochemistry of efflorescent minerals on mine tailings and their potential impact on water chemistry.

    PubMed

    Grover, B P C; Johnson, R H; Billing, D G; Weiersbye, I M G; Tutu, H

    2016-04-01

    In the gold mining Witwatersrand Basin of South Africa, efflorescent mineral crusts are a common occurrence on and nearby tailings dumps during the dry season. The crusts are readily soluble and generate acidic, metal- and sulphate-rich solutions on dissolution. In this study, the metal content of efflorescent crusts at an abandoned gold mine tailings dump was used to characterise surface and groundwater discharges from the site. Geochemical modelling of the pH of the solution resulting from the dissolution of the crusts was used to better understand the crusts' potential impact on water chemistry. The study involved two approaches: (i) conducting leaching experiments on oxidised and unoxidised tailings using artificial rainwater and dilute sulphuric acid and correlating the composition of crusts to these leachates and (ii) modelling the dissolution of the crusts in order to gain insight into their mineralogy and their potential impact on receiving waters. The findings suggested that there were two chemically distinct discharges from the site, namely an aluminium- and magnesium-rich surface water plume and an iron-rich groundwater plume. The first plume was observed to originate from the oxidised tailings following leaching with rainwater while the second plume originated from the underlying unoxidised tailings with leaching by sulphuric acid. Both groups of minerals forming from the respective plumes were found to significantly lower the pH of the receiving water with simulations of their dissolution found to be within 0.2 pH units of experimental values. It was observed that metals in a low abundance within the crust (for example, iron) had a stronger influence on the pH of the resulting solutions than metals in a greater abundance (aluminium or magnesium). Techniques such as powder X-ray diffraction (PXRD) and in situ mineral determination techniques such as remote sensing can effectively determine the dominant mineralogy. However, the minerals or metals

  13. ICON-ART-ISO: Water isotopologues implemented in the chemistry- transport model ICON-ART

    NASA Astrophysics Data System (ADS)

    Eckstein, Johannes; Ruhnke, Roland; Reinert, Daniel; Pfahl, Stephan

    2017-04-01

    Stable isotopes of water can help to understand processes that have influenced the distribution of water in the atmosphere. Isotope enabled models, capable of simulating the distribution of HDO and H218O, can be a very useful tool for understanding these processes and the distribution of isotope ratios which are observed. We present ICON-ART-ISO, the implementation of water isotopes into the chemistry-transport model ICON-ART. The core of this global model is the ICOsahedral Non-hydrostatic (ICON) modelling framework (Zaengl et al, 2015 (Q. J. R. Meteorol. Soc.)), a joint development of the German Weather Service (DWD) and the Max Planck Institute for Meteorology. The model system ICON-ART (Aerosols and Reactive Trace gases, Rieger et al, 2015 (GMD)) is a two-way coupled extension to ICON, which allows to study the influence of aerosols, trace gases and their chemistry on the atmosphere. We set up ICON-ART-ISO within this framework, profitting from the model infrastructure. We follow the implementation of COSMOiso (Pfahl et al., 2012 (ACP)), the isotope-enabled version of the COSMO model, the predecessor of ICON. In order to include the isotopes in the model, the water cycle is doubled diagnostically for each isotope. By the choice of physical parameters, these modelled isotopes are set to HDO and H218O, but the simulation of a purely diagnostic H2O is also possible. Fractionation, i.e. the change of the isotope ratio changes during phase changes, is considered in evaporation, grid-scale precipitation and convection. For the source of evaporation, a constant isotope ratio is currently used. To consider grid scale precipitation, the processes in the two-moment microphysical scheme by Seifert and Beheng, 2005 (Meteorol. Atmos. Phys.) are diagnostically applied to the isotopes. For convection, the Tiedtke-Bechtold scheme (Bechtold et al., 2013 (JAS)) is used. We present the current status of the model system. All processes have been implemented and we show first

  14. Impact of long term wetting on pore water chemistry in a peat bog in Ontario, Canada

    NASA Astrophysics Data System (ADS)

    Schaper, Jonas; Blodau, Christian; Holger Knorr, Klaus

    2013-04-01

    Peatlands of the northern hemisphere store a remarkable amount of carbon but also contribute to global methane emissions. As large areas in the boreal and subarctic zone are considered to undergo significant climate change it is necessary to understand how these ecosystems react to altered environmental conditions. Since not only temperatures but also precipitation is likely to increase in these regions, it is of particular interest to understand the impact of raised water tables and changing local hydrological flow patterns on peatlands' carbon cycle. We chose a pristine bog that was partly flooded by a reservoir lake created 60 years ago in Ontario, Canada. Water management in the reservoir resulted in seasonal flooding, shifting hydrological flow patterns and vegetation gradients. The impact of partial flooding on pore water chemistry and DIC and CH4 concentrations were studied within surface peat layers. Samples were taken with pore water peepers along the vegetation- and flooding gradient. Turnover rates of DIC and methane were calculated from obtained concentration profiles and peat porosity under the assumption that transport is dominated by diffusion. Values of pH changed remarkably from 4 within the undisturbed bog part to almost 8 at the lake shore. Ca2+ and Mg2+ were the only ions that showed significant distribution patterns with readily increasing concentrations towards the lake water body. CH4 and DIC concentrations also increased towards the lake and peaked in around 100 cm depth right at the shore with maximum concentrations being 2766 μmol L-1 for CH4 and 7543 μmol L-1 for DIC, respectively. Turnover rates also increased towards the shore albeit some uncertainty lies in this finding as steady state condition required for calculations were probably not established and transport was not only dominated by diffusion. Maximum CH4 production rates were modeled to be 36 nmol cm-3 d-1 and maximum DIC production was calculated to 64 nmol cm-3 d-1. Ca2

  15. Trends in Surface Water Chemistry in Acidified Areas in Europe and North America from 1990 to 2008

    EPA Science Inventory

    Acidification of lakes and rivers is still an environmental concern despite reduced emissions of acidifying compounds. We analyzed trends in surface water chemistry of 173 acid-sensitive sites from 12 regions in Europe and North America. In 11 of 12 regions, non-marine sulphate (...

  16. Mercury Redox Chemistry in Waters of the Eastern Asian Seas: From Polluted Coast to Clean Open Ocean.

    PubMed

    Ci, Zhijia; Zhang, Xiaoshan; Yin, Yongguang; Chen, Jinsheng; Wang, Shiwei

    2016-03-01

    We performed incubation experiments using seawaters from representative marine environments of the eastern Asian seas to determine the mercury (Hg) available for photoreduction (Hgr(II)), to investigate the Hg redox reaction kinetics, and to explore the effect of environmental factors and water chemistry on the Hg redox chemistry. Results show that Hgr(II) accounted for a considerable fraction of total Hg (THg) (%Hgr(II)/THg: 24.90 ± 10.55%, n = 27) and positively correlated with THg. Filtration decreased the Hgr(II) pool of waters with high suspended particulate matter (SPM). The positive linear relationships were found between pseudo-first order rate constants of gross Hg(II) photoreduction (kr) and gross Hg(0) photo-oxidation (ko) with photosynthetically active radiation (PAR). Under the condition of PAR of 1 m mol m(-2) s(-1), the kr were significantly (p < 0.05) lower than ko (kr/ko: 0.86 ± 0.22). The Hg(0) dark oxidation were significantly higher than the Hg(II) dark reduction. The Hg(II) dark reduction was positively correlated to THg, and the anaerobic condition favored the Hg(II) dark reduction. Filtration significantly influenced the Hg photoredox chemistry of waters with high SPM. UVB radiation was important for both Hg(II) photoreduction and Hg(0) photo-oxidation, and the role of other wavebands in photoinduced transformations of Hg varied with the water chemistry.

  17. Variation in chemistry of stream water and bulk deposition across the Hubbard Brook Valley, New Hampshire, USA

    Treesearch

    Gene E. Likens; Donald C. Buso; James W. Hornbeck

    2002-01-01

    Chemistry and volume of precipitation and stream water have been measured in south-facing watersheds of the Hubbard Brook Experimental Forest (HBEF), continuously for 37 years. These long-term data have provided important insights into the bio-geochemistry of these watershed ecosystems and the region (e.g. LIKENS & BORMANN 1995).

  18. Ecology of subtropical, shallow water environments: chemistry of copper and chlorine introduced into marine systems during energy production

    SciTech Connect

    Not Available

    1980-01-01

    During the last three contract years, we have been involved in the study of the chemistry of the copper binding compounds occurring in coastal seawater. Initially our efforts were oriented towards the study of the complexing capacity of waters collected at various locations in the Miami, Florida area. Our study then shifted towards the concentration and the elucidation of these chelators.

  19. Trends in Surface Water Chemistry in Acidified Areas in Europe and North America from 1990 to 2008

    EPA Science Inventory

    Acidification of lakes and rivers is still an environmental concern despite reduced emissions of acidifying compounds. We analyzed trends in surface water chemistry of 173 acid-sensitive sites from 12 regions in Europe and North America. In 11 of 12 regions, non-marine sulphate (...

  20. An Introduction to Boiler Water Chemistry for the Marine Engineer: A Text of Audio-Tutorial Instruction.

    ERIC Educational Resources Information Center

    Schlenker, Richard M.; And Others

    Presented is a manuscript for an introductory boiler water chemistry course for marine engineer education. The course is modular, self-paced, audio-tutorial, contract graded and combined lecture-laboratory instructed. Lectures are presented to students individually via audio-tapes and 35 mm slides. The course consists of a total of 17 modules -…

  1. Enhanced Control of PWR Primary Coolant Water Chemistry Using Selective Separation Systems for Recovery and Recycle of Enriched Boric Acid

    SciTech Connect

    Ken Czerwinski; Charels Yeamans; Don Olander; Kenneth Raymond; Norman Schroeder; Thomas Robison; Bryan Carlson; Barbara Smit; Pat Robinson

    2006-02-28

    The objective of this project is to develop systems that will allow for increased nuclear energy production through the use of enriched fuels. The developed systems will allow for the efficient and selective recover of selected isotopes that are additives to power water reactors' primary coolant chemistry for suppression of corrosion attack on reactor materials.

  2. Influence of bedrock geology on water chemistry of slope wetlands and headwater streams in the southern Rocky Mountains

    Treesearch

    Monique LaPerriere Nelson; Charles C. Rhoades; Kathleen A. Dwire

    2011-01-01

    We characterized the water chemistry of nine slope wetlands and adjacent headwater streams in Colorado subalpine forests and compared sites in basins formed on crystalline bedrock with those formed in basins with a mixture of crystalline and sedimentary bedrock. The pH, Ca2+, Mg2+, NH4 +, acid neutralizing capacity, and electrical conductivity of wetland porewater and...

  3. An Introduction to Boiler Water Chemistry for the Marine Engineer: A Text of Audio-Tutorial Instruction.

    ERIC Educational Resources Information Center

    Schlenker, Richard M.; And Others

    Presented is a manuscript for an introductory boiler water chemistry course for marine engineer education. The course is modular, self-paced, audio-tutorial, contract graded and combined lecture-laboratory instructed. Lectures are presented to students individually via audio-tapes and 35 mm slides. The course consists of a total of 17 modules -…

  4. The Effects of Classic and Web-Designed Conceptual Change Texts on the Subject of Water Chemistry

    ERIC Educational Resources Information Center

    Tas, Erol; Gülen, Salih; Öner, Zeynep; Özyürek, Cengiz

    2015-01-01

    The purpose of this study is to research the effects of traditional and web-assisted conceptual change texts for the subject of water chemistry on the success, conceptual errors and permanent learning of students. A total of 37 8th graders in a secondary school of Samsun participated in this study which had a random experimental design with…

  5. Preliminary assessment of water chemistry related to groundwater flooding in Wawarsing, New York, 2009-11

    USGS Publications Warehouse

    Brown, Craig J.; Eckhardt, David A.; Stumm, Frederick; Chu, Anthony

    2012-01-01

    Water-quality samples collected in an area prone to groundwater flooding in Wawarsing, New York, were analyzed and assessed to better understand the hydrologic system and to aid in the assessment of contributing water sources. Above average rainfall over the past decade, and the presence of a pressurized water tunnel that passes about 700 feet beneath Wawarsing, could both contribute to groundwater flooding. Water samples were collected from surface-water bodies, springs, and wells and analyzed for major and trace inorganic constituents, dissolved gases, age tracers, and stable isotopes. Distinct differences in chemistry exist between tunnel water and groundwater in unconsolidated deposits and in bedrock, and among groundwater samples collected from some bedrock wells during high head pressure and low head pressure of the Rondout-West Branch Tunnel. Samples from bedrock wells generally had relatively higher concentrations of sulfate (SO42-), strontium (Sr), barium (Ba), and lower concentrations of calcium (Ca) and bicarbonate (HCO3-), as compared to unconsolidated wells. Differences in stable-isotope ratios among oxygen-18 to oxygen-16 (δ18O), hydrogen-2 to hydrogen-1 (δ2H), sulfur-34 to sulfur-32(δ34S) of SO42-, Sr-87 to Sr-86 (87Sr/86Sr), and C-13 to C-12 (δ13C) of dissolved inorganic carbon (DIC) indicate a potential for distinguishing water in the Delaware-West Branch Tunnel from native groundwater. For example, 87Sr/86Sr ratios were more depleted in groundwater samples from most bedrock wells, as compared to samples from surface-water sources, springs, and wells screened in unconsolidated deposits in the study area. Age-tracer data provided useful information on pathways of the groundwater-flow system, but were limited by inherent problems with dissolved gases in bedrock wells. The sulfur hexafluoride (SF6) and (or) chlorofluorocarbons (CFCs) apparent recharge years of most water samples from wells screened in unconsolidated deposits and springs ranged

  6. Technical Development on Burn-up Credit for Spent LWR Fuel

    SciTech Connect

    Gauld, I.C.

    2001-12-26

    Technical development on burn-up credit for spent LWR fuels had been performed at JAERI since 1990 under the contract with Science and Technology Agency of Japan entitled ''Technical Development on Criticality Safety Management for Spent LWR Fuels.'' Main purposes of this work are to obtain the experimental data on criticality properties and isotopic compositions of spent LWR fuels and to verify burnup and criticality calculation codes. In this work three major experiments of exponential experiments for spent fuel assemblies to obtain criticality data, non-destructive gamma-ray measurement of spent fuel rods for evaluating axial burn-up profiles, and destructive analyses of spent fuel samples for determining precise burn-up and isotopic compositions were carried out. The measured data obtained were used for validating calculation codes as well as an examination of criticality safety analyses. Details of the work are described in this report.

  7. Achievement of world's best performance in Japanese LWR, through the successful development on fuels and materials

    NASA Astrophysics Data System (ADS)

    Yoshitsugu, Mishima

    1989-12-01

    Research and development on fuel and cladding materials in the past 40 years, which led to the excellent performance of today's Japanese LWR are overviewed. Most of the programs for the development of LWR fuels and Zircaloy cladding tube have been conducted by the author, starting from the metal uranium fuel rod for the research reactor JRR-3, then going on to the domestic production of fuel for the power-demonstration reactor JPDR. LWR fuel fabrication has been successfully performed on these bases together with the research and development work on Zircaloy tube fabrication technology among metal industries. Fundamental works and co-operative studies among specialists from every related field have been effectively combined with the development works among industry, which contributed to the achievement of the world's top level fuel and thus to the excellent performance of 36 LWRs in Japan, today.

  8. Properties, performance and associated hazards of state-of-the-art durable water repellent (DWR) chemistry for textile finishing.

    PubMed

    Holmquist, H; Schellenberger, S; van der Veen, I; Peters, G M; Leonards, P E G; Cousins, I T

    2016-05-01

    Following the phase-out of long-chain per- and polyfluoroalkyl substances (PFASs), the textile industry had to find alternatives for side-chain fluorinated polymer based durable water repellent (DWR) chemistries that incorporated long perfluoroalkyl side chains. This phase-out and subsequent substitution with alternatives has resulted in a market where both fluorinated and non-fluorinated DWRs are available. These DWR alternatives can be divided into four broad groups that reflect their basic chemistry: side-chain fluorinated polymers, silicones, hydrocarbons and other chemistries (includes dendrimer and inorganic nanoparticle chemistries). In this critical review, the alternative DWRs are assessed with regards to their structural properties and connected performance, loss and degradation processes resulting in diffuse environmental emissions, and hazard profiles for selected emitted substances. Our review shows that there are large differences in performance between the alternative DWRs, most importantly the lack of oil repellence of non-fluorinated alternatives. It also shows that for all alternatives, impurities and/or degradation products of the DWR chemistries are diffusively emitted to the environment. Our hazard ranking suggests that hydrocarbon based DWR is the most environmentally benign, followed by silicone and side-chain fluorinated polymer-based DWR chemistries. Industrial commitments to reduce the levels of impurities in silicone based and side-chain fluorinated polymer based DWR formulations will lower the actual risks. There is a lack of information on the hazards associated with DWRs, in particular for the dendrimer and inorganic nanoparticle chemistries, and these data gaps must be filled. Until environmentally safe alternatives, which provide the required performance, are available our recommendation is to choose DWR chemistry on a case-by-case basis, always weighing the benefits connected to increased performance against the risks to the

  9. Environmental chemistry. Seventh edition

    SciTech Connect

    Manahan, S.E.

    1999-11-01

    This book presents a basic understanding of environmental chemistry and its applications. In addition to providing updated materials in this field, the book emphasizes the major concepts essential to the practice of environmental chemistry. Topics of discussion include the following: toxicological chemistry; toxicological chemistry of chemical substances; chemical analysis of water and wastewater; chemical analysis of wastes and solids; air and gas analysis; chemical analysis of biological materials and xenobiotics; fundamentals of chemistry; and fundamentals of organic chemistry.

  10. Experimental study of water-ice catalyzed thermal isomerization of cyanamide into carbodiimide: implication for prebiotic chemistry.

    PubMed

    Duvernay, Fabrice; Chiavassa, Thierry; Borget, Fabien; Aycard, Jean-Pierre

    2004-06-30

    Cyanamide (NH2CN) is a molecule of interstellar interest which can be implied in prebiotic chemistry. We showed, by FTIR spectroscopy, that cyanamide can be isomerized in carbodiimide (HNCNH), another interstellar relevant molecule, by a reaction involving the amorphous water-ice surface as catalyst. This isomerization occurs at low temperature (T < 100 K) which agrees quite well with that expected in the interstellar clouds composed of dust grains in which water is the most predominant constituent.

  11. Ground Water Chemistry Changes before Major Earthquakes and Possible Effects on Animals

    PubMed Central

    Grant, Rachel A.; Halliday, Tim; Balderer, Werner P.; Leuenberger, Fanny; Newcomer, Michelle; Cyr, Gary; Freund, Friedemann T.

    2011-01-01

    Prior to major earthquakes many changes in the environment have been documented. Though often subtle and fleeting, these changes are noticeable at the land surface, in water, in the air, and in the ionosphere. Key to understanding these diverse pre-earthquake phenomena has been the discovery that, when tectonic stresses build up in the Earth’s crust, highly mobile electronic charge carriers are activated. These charge carriers are defect electrons on the oxygen anion sublattice of silicate minerals, known as positive holes, chemically equivalent to O− in a matrix of O2−. They are remarkable inasmuch as they can flow out of the stressed rock volume and spread into the surrounding unstressed rocks. Travelling fast and far the positive holes cause a range of follow-on reactions when they arrive at the Earth’s surface, where they cause air ionization, injecting massive amounts of primarily positive air ions into the lower atmosphere. When they arrive at the rock-water interface, they act as •O radicals, oxidizing water to hydrogen peroxide. Other reactions at the rock-water interface include the oxidation or partial oxidation of dissolved organic compounds, leading to changes of their fluorescence spectra. Some compounds thus formed may be irritants or toxins to certain species of animals. Common toads, Bufo bufo, were observed to exhibit a highly unusual behavior prior to a M6.3 earthquake that hit L’Aquila, Italy, on April 06, 2009: a few days before the seismic event the toads suddenly disappeared from their breeding site in a small lake about 75 km from the epicenter and did not return until after the aftershock series. In this paper we discuss potential changes in groundwater chemistry prior to seismic events and their possible effects on animals. PMID:21776211

  12. Response of fish and macroinvertebrate bioassessment indices to water chemistry in a mined Appalachian watershed

    SciTech Connect

    Freund, Jason; Petty, J.

    2007-05-15

    Multimetric indices based on fish and benthic macroinvertebrate assemblages are commonly used to assess the biological integrity of aquatic ecosystems. However, their response to specific stressors is rarely known. We quantified the response of a fish-based index (Mid-Atlantic Highlands Index of Biotic Integrity, MAH-IBI) and a benthic invertebrate-based index (West Virginia Stream Condition Index, WV-SCI) to acid mine drainage (AMD)-related stressors in 46 stream sites within the Cheat River watershed, West Virginia. We also identified specific stressor concentrations at which biological impairment was always or never observed. Water chemistry was extremely variable among tributaries of the Cheat River, and the WV-SCI was highly responsive across a range of AMD stressor levels. Furthermore, impairment to macroinvertebrate communities was observed at relatively low stressor concentrations, especially when compared to state water quality standards. In contrast to the WV-SCI, we found that the MAH-IBI was significantly less responsive to local water quality conditions. Low fish diversity was observed in several streams that possessed relatively good water quality. This pattern was especially pronounced in highly degraded subwatersheds, suggesting that regional conditions may have a strong influence on fish assemblages in this system. Our results indicate that biomonitoring programs in mined watersheds should include both benthic invertebrates, which are consistent indicators of local conditions, and fishes, which may be indicators of regional conditions. In addition, remediation programs must address the full suite of chemical constituents in AMD and focus on improving linkages among streams within drainage networks to ensure recovery of invertebrate and fish assemblages.

  13. Evolution of water chemistry in natural acidic environments in Yangmingshan, Taiwan.

    PubMed

    Ezoe, Yuka; Lin, Cheng-Huang; Noto, Masami; Watanabe, Yoshihiro; Yoshimura, Kazuhisa

    2002-08-01

    In Yangmingshan National Park, located in the northern part of the Taiwan Island, there is a very rare area where fish (Channa asiatica) live in spite of acid environments. The origin of the acid in local acid ponds and rivers and the evolution of the water chemistry are discussed on the basis of sulfur stable isotope ratios and chemical equilibria. One of the sources of the acid is sulfuric acid, which is derived from the oxidation of hydrogen sulfide in volcanic gas gushing out from fumaroles around the area and from acid deposition supplied from Taipei City. It is also derived from the oxidation of pyrite: the sulfur stable isotope ratios of delta 34S of +1@1000 to +4@1000 (relative to CDT) of sulfate in acid pond waters (pH 3-4) could be related to those of hydrogen sulfide in volcanic gas, pyrite in local pond sediments and soils, and sulfate in rain water. One acid source is sulfuric and hydrochloric acids arising in springs from geothermal activity: the delta 34S values were characterised by +13@1000 to +17@1000 sulfate-S, which was provided by a disproportionation reaction of sulfur dioxide in the depths. Another acid source could be the oxidation of iron(II). Under acidic conditions, the water-rock reaction gives rise to high concentrations of aluminium and iron. While flowing down surface streams, iron(II) is oxidised to iron(III) and then hydrolysed to cause further acidification under oxic conditions. The concentrations of iron and aluminium are controlled by redox and dissolution equilibria.

  14. Water chemistry of lakes related to active and inactive Mexican volcanoes

    NASA Astrophysics Data System (ADS)

    Armienta, María Aurora; Vilaclara, Gloria; De la Cruz-Reyna, Servando; Ramos, Silvia; Ceniceros, Nora; Cruz, Olivia; Aguayo, Alejandra; Arcega-Cabrera, Flor

    2008-12-01

    Water chemistry of crater lakes, maars and water reservoirs linked to some Mexican volcanoes within and outside the Mexican Volcanic Belt has been determined for several years and examined regarding environmental and volcanic factors. All the analyzed lakes are relatively small with a maximum depth of 65 m, and are located in regions with different climates, from semi-arid to very humid, with altitudes ranging from 100 to more than 4000 m a.s.l. Crater lakes in active volcanoes (El Chichón, Popocatépetl) have very low pH, moderate to high temperatures and major ion concentrations varying with the level of volcanic unrest. Lakes in sub-arid and temperate-arid regions (like maars in Puebla and Guanajuato states) show high alkalinity and pH, with bicarbonate/carbonate, chloride, sodium and magnesium as predominant ions. Lakes located in humid climates (Central Michoacán and Veracruz state) have low mineralization and near-neutral pH values. In general, conservative dissolved ions and conductivity appear to be mostly controlled by precipitation/evaporation and by the ionic concentration of groundwater inputs. Calcium, magnesium, sulfate concentrations and pH are strongly influenced by volcanic-rock or volcanic gas interactions with water. The influence of low-level volcanic activity on crater lakes may be obscured by water-rock interactions, and climatic factors. One of the aims of this paper is to define the relative influence of these factors searching for a reference frame to recognize the early volcanic precursors in volcano-related lakes.

  15. Response of fish and macroinvertebrate bioassessment indices to water chemistry in a mined Appalachian watershed.

    PubMed

    Freund, Jason G; Petty, J Todd

    2007-05-01

    Multimetric indices based on fish and benthic macroinvertebrate assemblages are commonly used to assess the biological integrity of aquatic ecosystems. However, their response to specific stressors is rarely known. We quantified the response of a fish-based index (Mid-Atlantic Highlands Index of Biotic Integrity, MAH-IBI) and a benthic invertebrate-based index (West Virginia Stream Condition Index, WV-SCI) to acid mine drainage (AMD)-related stressors in 46 stream sites within the Cheat River watershed, West Virginia. We also identified specific stressor concentrations at which biological impairment was always or never observed. Water chemistry was extremely variable among tributaries of the Cheat River, and the WV-SCI was highly responsive across a range of AMD stressor levels. Furthermore, impairment to macroinvertebrate communities was observed at relatively low stressor concentrations, especially when compared to state water quality standards. In contrast to the WV-SCI, we found that the MAH-IBI was significantly less responsive to local water quality conditions. Low fish diversity was observed in several streams that possessed relatively good water quality. This pattern was especially pronounced in highly degraded subwatersheds, suggesting that regional conditions may have a strong influence on fish assemblages in this system. Our results indicate that biomonitoring programs in mined watersheds should include both benthic invertebrates, which are consistent indicators of local conditions, and fishes, which may be indicators of regional conditions. In addition, remediation programs must address the full suite of chemical constituents in AMD and focus on improving linkages among streams within drainage networks to ensure recovery of invertebrate and fish assemblages. Future research should identify the precise chemical conditions necessary to maintain biological integrity in mined Appalachian watersheds.

  16. Ground water chemistry changes before major earthquakes and possible effects on animals.

    PubMed

    Grant, Rachel A; Halliday, Tim; Balderer, Werner P; Leuenberger, Fanny; Newcomer, Michelle; Cyr, Gary; Freund, Friedemann T

    2011-06-01

    Prior to major earthquakes many changes in the environment have been documented. Though often subtle and fleeting, these changes are noticeable at the land surface, in water, in the air, and in the ionosphere. Key to understanding these diverse pre-earthquake phenomena has been the discovery that, when tectonic stresses build up in the Earth's crust, highly mobile electronic charge carriers are activated. These charge carriers are defect electrons on the oxygen anion sublattice of silicate minerals, known as positive holes, chemically equivalent to O- in a matrix of O2-. They are remarkable inasmuch as they can flow out of the stressed rock volume and spread into the surrounding unstressed rocks. Travelling fast and far the positive holes cause a range of follow-on reactions when they arrive at the Earth's surface, where they cause air ionization, injecting massive amounts of primarily positive air ions into the lower atmosphere. When they arrive at the rock-water interface, they act as •O radicals, oxidizing water to hydrogen peroxide. Other reactions at the rock-water interface include the oxidation or partial oxidation of dissolved organic compounds, leading to changes of their fluorescence spectra. Some compounds thus formed may be irritants or toxins to certain species of animals. Common toads, Bufo bufo, were observed to exhibit a highly unusual behavior prior to a M6.3 earthquake that hit L'Aquila, Italy, on April 06, 2009: a few days before the seismic event the toads suddenly disappeared from their breeding site in a small lake about 75 km from the epicenter and did not return until after the aftershock series. In this paper we discuss potential changes in groundwater chemistry prior to seismic events and their possible effects on animals.

  17. Addressing the complexity of water chemistry in environmental fate modeling for engineered nanoparticles.

    PubMed

    Sani-Kast, Nicole; Scheringer, Martin; Slomberg, Danielle; Labille, Jérôme; Praetorius, Antonia; Ollivier, Patrick; Hungerbühler, Konrad

    2015-12-01

    Engineered nanoparticle (ENP) fate models developed to date - aimed at predicting ENP concentration in the aqueous environment - have limited applicability because they employ constant environmental conditions along the modeled system or a highly specific environmental representation; both approaches do not show the effects of spatial and/or temporal variability. To address this conceptual gap, we developed a novel modeling strategy that: 1) incorporates spatial variability in environmental conditions in an existing ENP fate model; and 2) analyzes the effect of a wide range of randomly sampled environmental conditions (representing variations in water chemistry). This approach was employed to investigate the transport of nano-TiO2 in the Lower Rhône River (France) under numerous sets of environmental conditions. The predicted spatial concentration profiles of nano-TiO2 were then grouped according to their similarity by using cluster analysis. The analysis resulted in a small number of clusters representing groups of spatial concentration profiles. All clusters show nano-TiO2 accumulation in the sediment layer, supporting results from previous studies. Analysis of the characteristic features of each cluster demonstrated a strong association between the water conditions in regions close to the ENP emission source and the cluster membership of the corresponding spatial concentration profiles. In particular, water compositions favoring heteroaggregation between the ENPs and suspended particulate matter resulted in clusters of low variability. These conditions are, therefore, reliable predictors of the eventual fate of the modeled ENPs. The conclusions from this study are also valid for ENP fate in other large river systems. Our results, therefore, shift the focus of future modeling and experimental research of ENP environmental fate to the water characteristic in regions near the expected ENP emission sources. Under conditions favoring heteroaggregation in these

  18. Evidence of a change in water chemistry in Canada's subarctic associated with enhanced winter streamflow

    NASA Astrophysics Data System (ADS)

    Spence, C.; Kokelj, S. V.; Kokelj, S. A.; McCluskie, M.; Hedstrom, N.

    2015-01-01

    winter streamflow is a characteristic of a nival/pluvial regime that has emerged in parts of the subarctic Canadian Shield because of increasingly common late summer rains. This phenomenon is part of a widespread trend toward higher winter streamflow in watersheds across the circumpolar north. There may be implications for biogeochemical systems as streamflow regimes undergo these types of changes associated with climate warming. Streamflow and geochemical fluxes were observed over 2 years with different winter flow conditions in a subarctic Canadian Shield catchment. Results show that higher wintertime loads of carbon and solutes associated with enhanced winter streamflow were in association with an expansion of contributing areas to run off over what would have existed during typical winter recession. Furthermore, the wet fall conditions that lead to enhanced winter streamflow require water tables close to the topographic surface in highly conductive organic soil layers, which is a similar to the condition during the spring melt. Fall rainfall-runoff leaves an ample volume of water in the lakes that are ubiquitous in this landscape. This water maintains winter streamflow during a time when it traditionally would have ceased. A slowing of biological activity under lake ice increases net mineralization and nitrification rates. This convergence of nitrogen cycling and winter streamflow produced a disproportionate flux of inorganic nitrogen from the study catchment. A conceptual model of how enhanced winter streamflow changes water chemistry in a lake-dominated shield landscape is proposed and may be used as a benchmark to guide hypotheses of process interactions, change in other landscapes, or across scales.

  19. Organic geochemistry and pore water chemistry of sediments from Mangrove Lake, Bermuda

    USGS Publications Warehouse

    Hatcher, P.G.; Simoneit, B.R.T.; MacKenzie, F.T.; Neumann, A.C.; Thorstenson, D.C.; Gerchakov, S.M.

    1982-01-01

    Mangrove Lake, Bermuda, is a small coastal, brackish-water lake that has accumulated 14 m of banded, gelatinous, sapropelic sediments in less than 104 yr. Stratigraphic evidence indicates that Mangrove Lake's sedimentary environment has undergone three major depositional changes (peat, freshwater gel, brackish-water gel) as a result of sea level changes. The deposits were examined geochemically in an effort to delineate sedimentological and diagenetic changes. Gas and pore water studies include measurements of sulfides, ammonia, methane, nitrogen gas, calcium, magnesium, chloride, alkalinity, and pH. Results indicate that sulfate reduction is complete, and some evidence is presented for bacterial denitrification and metal sulfide precipitation. The organic-rich sapropel is predominantly algal in origin, composed mostly of carbohydrates and insoluble macromolecular organic matter called humin with minor amounts of proteins, lipids, and humic acids. Carbohydrates and proteins undergo hydrolysis with depth in the marine sapropel but tend to be preserved in the freshwater sapropel. The humin, which has a predominantly aliphatic structure, increases linearly with depth and composes the greatest fraction of the organic matter. Humic acids are minor components and are more like polysaccharides than typical marine humic acids. Fatty acid distributions reveal that the lipids are of an algal and/or terrestrial plant source. Normal alkanes with a total concentration of 75 ppm exhibit two distribution maxima. One is centered about n-C22 with no odd/even predominance, suggestive of a degraded algal source. The other is centered at n-C31 with a distinct odd/even predominance indicative of a vascular plant origin. Stratigraphic changes in the sediment correlate to observed changes in the gas and pore water chemistry and the organic geochemistry. ?? 1982.

  20. Evolution of the chemistry of Fe bearing waters during CO2 degassing

    USGS Publications Warehouse

    Geroni, J.N.; Cravotta, C.A.; Sapsford, D.J.

    2012-01-01

    The rates of Fe(II) oxidation and precipitation from groundwater are highly pH dependent. Elevated levels of dissolved CO2 can depress pH and cause difficulty in removing dissolved Fe and associated metals during treatment of ferruginous water. This paper demonstrates interdependent changes in pH, dissolved inorganic C species, and Fe(II) oxidation rates that occur as a result of the removal (degassing) of CO2 during aeration of waters discharged from abandoned coal mines. The results of field monitoring of aeration cascades at a treatment facility as well as batchwise aeration experiments conducted using net alkaline and net acidic waters in the UK are combined with geochemical modelling to demonstrate the spatial and temporal evolution of the discharge water chemistry. The aeration cascades removed approximately 67% of the dissolved CO2 initially present but varying the design did not affect the concentration of Fe(II) leaving the treatment ponds. Continued removal of the residual CO2 by mechanical aeration increased pH by as much as 2 units and resulted in large increases in the rates of Fe(II) oxidation and precipitation. Effective exsolution of CO2 led to a reduction in the required lime dose for removal of remaining Fe(II), a very important factor with regard to increasing the sustainability of treatment practices. An important ancillary finding for passive treatment is that varying the design of the cascades had little impact on the rate of CO2 removal at the flow rates measured.

  1. Interactions between hydrology and water chemistry shape bacterioplankton biogeography across boreal freshwater networks.

    PubMed

    Niño-García, Juan Pablo; Ruiz-González, Clara; Del Giorgio, Paul A

    2016-07-01

    Disentangling the mechanisms shaping bacterioplankton communities across freshwater ecosystems requires considering a hydrologic dimension that can influence both dispersal and local sorting, but how the environment and hydrology interact to shape the biogeography of freshwater bacterioplankton over large spatial scales remains unexplored. Using Illumina sequencing of the 16S ribosomal RNA gene, we investigate the large-scale spatial patterns of bacterioplankton across 386 freshwater systems from seven distinct regions in boreal Québec. We show that both hydrology and local water chemistry (mostly pH) interact to shape a sequential structuring of communities from highly diverse assemblages in headwater streams toward larger rivers and lakes dominated by fewer taxa. Increases in water residence time along the hydrologic continuum were accompanied by major losses of bacterial richness and by an increased differentiation of communities driven by local conditions (pH and other related variables). This suggests that hydrology and network position modulate the relative role of environmental sorting and mass effects on community assembly by determining both the time frame for bacterial growth and the composition of the immigrant pool. The apparent low dispersal limitation (that is, the lack of influence of geographic distance on the spatial patterns observed at the taxonomic resolution used) suggests that these boreal bacterioplankton communities derive from a shared bacterial pool that enters the networks through the smallest streams, largely dominated by mass effects, and that is increasingly subjected to local sorting of species during transit along the hydrologic continuum.

  2. Investigation into the effect of water chemistry on corrosion product formation in areas of accelerated flow

    NASA Astrophysics Data System (ADS)

    McGrady, John; Scenini, Fabio; Duff, Jonathan; Stevens, Nicholas; Cassineri, Stefano; Curioni, Michele; Banks, Andrew

    2017-09-01

    The deposition of CRUD (Chalk River Unidentified Deposit) in the primary circuit of a Pressurised Water Reactor (PWR) is known to preferentially occur in regions of the circuit where flow acceleration of coolant occurs. A micro-fluidic flow cell was used to recreate accelerated flow under simulated PWR conditions, by flowing water through a disc with a central micro-orifice. CRUD deposition was reproduced on the disc, and CRUD Build-Up Rates (BUR) in various regions of the disc were analysed. The effect of the local environment on BUR was investigated. In particular, the effect of flow velocity, specimen material and Fe concentration were considered. The morphology and composition of the deposits were analysed with respect to experimental conditions. The BUR of CRUD was found to be sensitive to flow velocity and Fe concentration, suggesting that mass transfer is an important factor. The morphology of the deposit was affected by the specimen material indicating a dependence on surface/particle electrostatics meaning surface chemistry plays an important role in deposition. The preferential deposition of CRUD in accelerated flow regions due to electrokinetic effects was observed and it was shown that higher Fe concentrations in solution increased BURs within the orifice whereas increased flow velocity reduced BURs.

  3. Effects of water chemistry on intergranular cracking of irradiated austenitic stainless steels

    SciTech Connect

    Chung, H.M.; Ruther, W.E.; Sanecki, J.E.; Hins, A.; Kassner, T.F.

    1995-12-31

    To determine the effects of water chemistry on the susceptibility to irradiation-assisted stress corrosion cracking (IASCC) in austenitic stainless steels, constant-extension-rate tests were conducted in simulated BWR environments on several heats of high- and commercial-purity (HP and CP) Type 304 SS specimens from BWR components irradiated to fluences up to 2.4 {times} 10{sup 21} n cm{sup {minus}2} (E > 1 MeV). Effects of dissolved oxygen (DO) and electrochemical potential (ECP) in 289 C water were investigated. Dependence of susceptibility to intergranular stress corrosion cracking (IGSCC) on DO was somewhat different for the two materials. Susceptibility of the HP heats, less influenced by DO and ECP, was higher than that of CP material for all DO and fluence levels. Percent IGSCC in the CP material was negligible for DO < 0.01 ppm or ECP <{minus}140 mV SHE. Results of analysis by Auger electron spectroscopy indicated that the HP neutron absorber tubes were characterized by relatively lower concentrations of Cr, Ni, and Li and relatively higher concentrations of F and N on grain boundaries than those of the CP materials. It is suggested that a synergism between irradiation-induced grain-boundary Cr depletion and fabrication-related fluorine contamination plays an important role in the stress corrosion cracking behavior of the HP neutron absorber tubes.

  4. Computing gas solubility in reservoir waters for environmental chemistry applications: the role of satellite observations

    NASA Astrophysics Data System (ADS)

    Rosa, R.; Lima, I.; Ramos, F.; Bambace, L.; Assireu, A.; Stech, J.; Novo, E.; Lorenzeti, L.

    Atmospheric greenhouse gases concentration has increased during the past centuries basically due to biogenic and pyrogenic anthopogenic emissions Recent investigations have shown that gas emission methane as an important example from tropical hydroelectric reservoirs may comprise a considerable fraction of the total anthropogenic bulk In order to evaluate the concentration of gases of potential importance in environmental chemistry the solubility of such gases have been collected and converted into a uniform format using the Henry s law which states that the solubility of a gas in a liquid is directly proportional to its partial pressure However the Henry s law can be derived as a function of temperature density molar mixing ratio in the aqueous phase and molar mass of water In this paper we show that due to the complex temperature variation and water composition measured in brazilian tropical reservoirs as Serra da Mesa and Manso expressive secular variation on the traditional solubility constants concentration of a species in the aqueous phase by the partial pressure of that species in the gas phase can change in a rate of approximately 30 in 6 decades This estimation comes from a computational analysis of temperature variation measured during 6 months in Serra da Mesa and Manso reservoirs taking into account a simulated density and molar mass variation of the aqueous composition in these environments As an important global change issue from this preliminary analysis we discuss its role in the current estimations on the concentration emission rates

  5. "Click" and Olefin Metathesis Chemistry in Water at Room Temperature Enabled by Biodegradable Micelles.

    PubMed

    Lipshutz, Bruce H; Bošković, Zarko; Crowe, Christopher S; Davis, Victoria K; Whittemore, Hannah C; Vosburg, David A; Wenzel, Anna G

    2013-11-12

    The two laboratory reactions focus on teaching several concepts associated with green chemistry. Each uses a commercial, nontoxic, and biodegradable surfactant, TPGS-750-M, to promote organic reactions within the lipophilic cores of nanoscale micelles in water. These experiments are based on work by K. Barry Sharpless (an azide-alkyne "click" reaction) and Robert Grubbs (an olefin cross-metathesis reaction); both are suitable for an undergraduate organic laboratory. The copper-catalyzed azide-alkyne [3+2] cycloaddition of benzyl azide and 4-tolylacetylene is very rapid: the triazole product is readily isolated by filtration and is characterized by thin-layer chromatography and melting point analysis. The ruthenium-catalyzed olefin cross-metathesis reaction of benzyl acrylate with 1-hexene is readily monitored by thin-layer chromatography and gas chromatography. The metathesis experiment comparatively evaluates the efficacy of a TPGS-750-M/water medium relative to a traditional reaction performed in dichloromethane (a common solvent used for olefin metathesis).

  6. “Click” and Olefin Metathesis Chemistry in Water at Room Temperature Enabled by Biodegradable Micelles

    PubMed Central

    Lipshutz, Bruce H.; Bošković, Zarko; Crowe, Christopher S.; Davis, Victoria K.; Whittemore, Hannah C.; Vosburg, David A.; Wenzel, Anna G.

    2013-01-01

    The two laboratory reactions focus on teaching several concepts associated with green chemistry. Each uses a commercial, nontoxic, and biodegradable surfactant, TPGS-750-M, to promote organic reactions within the lipophilic cores of nanoscale micelles in water. These experiments are based on work by K. Barry Sharpless (an azide–alkyne “click” reaction) and Robert Grubbs (an olefin cross-metathesis reaction); both are suitable for an undergraduate organic laboratory. The copper-catalyzed azide–alkyne [3+2] cycloaddition of benzyl azide and 4-tolylacetylene is very rapid: the triazole product is readily isolated by filtration and is characterized by thin-layer chromatography and melting point analysis. The ruthenium-catalyzed olefin cross-metathesis reaction of benzyl acrylate with 1-hexene is readily monitored by thin-layer chromatography and gas chromatography. The metathesis experiment comparatively evaluates the efficacy of a TPGS-750-M/water medium relative to a traditional reaction performed in dichloromethane (a common solvent used for olefin metathesis). PMID:24324282

  7. Long-term disturbance of ground water chemistry following well installation.

    PubMed

    Kim, Kangjoo

    2003-01-01

    Ground water samples collected from a multilevel sampler shortly after its construction showed significantly higher alkalinity and concentrations of calcium and magnesium than those from nearby wells installed 10 years earlier. The sampler was drilled using a conventional hollow-stem power auger in a sandy, silicate aquifer lying beneath an isthmus between two lakes in northern Wisconsin. Ground water in the study area is of low ionic strength and its chemistry is dominated by silicate mineral weathering. Periodic sampling over two years following installation of the sampler showed that the higher solute concentrations had subsequently decreased. Oxygen isotope signature and other solute species, such as sulfate and chloride, were comparable to those of older wells and did not show any notable trends over time. Independent variation of other chemical species that cannot be derived from aquifer minerals, and the similarly high concentrations in older wells shortly after their installation, suggest that rapid dissolution of fresh mineral surfaces and hyperfine particles generated during drilling has induced the enhanced concentrations. This observation is consistent with the field equivalent of laboratory mineral dissolution experiments that show initially increased dissolution rates that decay over time. Well installations for geochemical sampling in dominantly silicate material may require longer times to reach an equilibrium state than has been previously thought.

  8. Host-guest chemistry with water-soluble gold nanoparticle supraspheres

    NASA Astrophysics Data System (ADS)

    Wang, Yizhan; Zeiri, Offer; Raula, Manoj; Le Ouay, Benjamin; Stellacci, Francesco; Weinstock, Ira A.

    2017-02-01

    The uptake of molecular guests, a hallmark of the supramolecular chemistry of cages and containers, has yet to be documented for soluble assemblies of metal nanoparticles. Here we demonstrate that gold nanoparticle-based supraspheres serve as a host for the hydrophobic uptake, transport and subsequent release of over two million organic guests, exceeding by five orders of magnitude the capacities of individual supramolecular cages or containers and rivalling those of zeolites and metal-organic frameworks on a mass-per-volume basis. The supraspheres are prepared in water by adding hexanethiol to polyoxometalate-protected 4 nm gold nanoparticles. Each 200 nm assembly contains hydrophobic cavities between the estimated 27,400 gold building blocks that are connected to one another by nanometre-sized pores. This gives a percolated network that effectively absorbs large numbers of molecules from water, including 600,000, 2,100,000 and 2,600,000 molecules (35, 190 and 234 g l-1) of para-dichorobenzene, bisphenol A and trinitrotoluene, respectively.

  9. Stream water chemistry in the arsenic-contaminated Baccu Locci mine watershed (Sardinia, Italy) after remediation.

    PubMed

    Ardau, Carla; Podda, Francesca; Da Pelo, Stefania; Frau, Franco

    2013-11-01

    The abandoned Pb-As Baccu Locci mine represents the first and only case of mine site remediation in Sardinia, Italy. Arsenic is the most relevant environmental concern in the Baccu Locci stream watershed, with concentrations in surface waters up to and sometimes over 1 mg/L. The main remediation action consisted in creation of a "storage site", for the collection of contaminated materials from different waste-rock dumps and most of tailings piles occurring along the Baccu Locci stream. This paper reports preliminary results on the level of contamination in the Baccu Locci stream after the completion of remediation measures. Post-remediation stream water chemistry has not substantially changed compared to the pre-remediation situation. In particular, dissolved As maintains an increasing trend along the Baccu Locci stream, with a concentration of about 400 μg/L measured at a distance of 7 km from the storage site. Future monitoring will provide fundamental information on the effectiveness of remediation actions conducted and their applicability to other mine sites in Sardinia. At the stage of mine site characterisation of future remediation plans, it is recommended to pay more attention to the understanding of mineralogical and geochemical processes responsible for pollution. Moreover, mixing of materials with different composition and reactivity in a storage site should require careful consideration and long-term leaching tests.

  10. Redox chemistry of molybdenum in natural waters and its involvement in biological evolution

    PubMed Central

    Wang, Deli

    2012-01-01

    The transition element molybdenum (Mo) possesses diverse valances (+II to +VI), and is involved in forming cofactors in more than 60 enzymes in biology. Redox switching of the element in these enzymes catalyzes a series of metabolic reactions in both prokaryotes and eukaryotes, and the element therefore plays a fundamental role in the global carbon, nitrogen, and sulfur cycling. In the present oxygenated waters, oxidized Mo(VI) predominates thermodynamically, whilst reduced Mo species are mainly confined within specific niches including cytoplasm. Only recently has the reduced Mo(V) been separated from Mo(VI) in sulfidic mats and even in some reducing waters. Given the presence of reduced Mo(V) in contemporary anaerobic habitats, it seems that reduced Mo species were present in the ancient reducing ocean (probably under both ferruginous and sulfidic conditions), prompting the involvement of Mo in enzymes including nitrogenase and nitrate reductase. During the global transition to oxic conditions, reduced Mo species were constrained to specific anaerobic habitats, and efficient uptake systems of oxidized Mo(VI) became a selective advantage for current prokaryotic and eukaryotic cells. Some prokaryotes are still able to directly utilize reduced Mo if any exists in ambient environments. In total, this mini-review describes the redox chemistry and biogeochemistry of Mo over the Earth’s history. PMID:23267355

  11. Host-guest chemistry with water-soluble gold nanoparticle supraspheres

    NASA Astrophysics Data System (ADS)

    Wang, Yizhan; Zeiri, Offer; Raula, Manoj; Le Ouay, Benjamin; Stellacci, Francesco; Weinstock, Ira A.

    2016-11-01

    The uptake of molecular guests, a hallmark of the supramolecular chemistry of cages and containers, has yet to be documented for soluble assemblies of metal nanoparticles. Here we demonstrate that gold nanoparticle-based supraspheres serve as a host for the hydrophobic uptake, transport and subsequent release of over two million organic guests, exceeding by five orders of magnitude the capacities of individual supramolecular cages or containers and rivalling those of zeolites and metal-organic frameworks on a mass-per-volume basis. The supraspheres are prepared in water by adding hexanethiol to polyoxometalate-protected 4 nm gold nanoparticles. Each 200 nm assembly contains hydrophobic cavities between the estimated 27,400 gold building blocks that are connected to one another by nanometre-sized pores. This gives a percolated network that effectively absorbs large numbers of molecules from water, including 600,000, 2,100,000 and 2,600,000 molecules (35, 190 and 234 g l‑1) of para-dichorobenzene, bisphenol A and trinitrotoluene, respectively.

  12. Mechanistic Insights on the Photosensitized Chemistry of a Fatty Acid at the Air/Water Interface

    PubMed Central

    2016-01-01

    Interfaces are ubiquitous in the environment and many atmospheric key processes, such as gas deposition, aerosol, and cloud formation are, at one stage or another, strongly impacted by physical and chemical processes occurring at interfaces. Here, the photoinduced chemistry of an air/water interface coated with nonanoic acid—a fatty acid surfactant we use as a proxy for chemically complex natural aqueous surface microlayers—was investigated as a source of volatile and semivolatile reactive organic species. The carboxylic acid coating significantly increased the propensity of photosensitizers, chosen to mimic those observed in real environmental waters, to partition to the interface and enhance reactivity there. Photochemical formation of functionalized and unsaturated compounds was systematically observed upon irradiation of these coated surfaces. The role of a coated interface appears to be critical in providing a concentrated medium allowing radical–radical reactions to occur in parallel with molecular oxygen additions. Mechanistic insights are provided from extensive analysis of products observed in both gas and aqueous phases by online switchable reagent ion-time of flight-mass spectrometry and by off-line ultraperformance liquid chromatography coupled to a Q Exactive high resolution mass spectrometer through heated electrospray ionization, respectively. PMID:27611489

  13. Redox chemistry of molybdenum in natural waters and its involvement in biological evolution.

    PubMed

    Wang, Deli

    2012-01-01

    The transition element molybdenum (Mo) possesses diverse valances (+II to +VI), and is involved in forming cofactors in more than 60 enzymes in biology. Redox switching of the element in these enzymes catalyzes a series of metabolic reactions in both prokaryotes and eukaryotes, and the element therefore plays a fundamental role in the global carbon, nitrogen, and sulfur cycling. In the present oxygenated waters, oxidized Mo(VI) predominates thermodynamically, whilst reduced Mo species are mainly confined within specific niches including cytoplasm. Only recently has the reduced Mo(V) been separated from Mo(VI) in sulfidic mats and even in some reducing waters. Given the presence of reduced Mo(V) in contemporary anaerobic habitats, it seems that reduced Mo species were present in the ancient reducing ocean (probably under both ferruginous and sulfidic conditions), prompting the involvement of Mo in enzymes including nitrogenase and nitrate reductase. During the global transition to oxic conditions, reduced Mo species were constrained to specific anaerobic habitats, and efficient uptake systems of oxidized Mo(VI) became a selective advantage for current prokaryotic and eukaryotic cells. Some prokaryotes are still able to directly utilize reduced Mo if any exists in ambient environments. In total, this mini-review describes the redox chemistry and biogeochemistry of Mo over the Earth's history.

  14. Effect of long-term application of biosolids for land reclamation on surface water chemistry.

    PubMed

    Tian, G; Granato, T C; Pietz, R I; Carlson, C R; Abedin, Z

    2006-01-01

    Biosolids are known to have a potential to restore degraded land, but the long-term impacts of this practice on the environment, including water quality, still need to be evaluated. The surface water chemistry (NO3-, NH4+, and total P, Cd, Cu, and Hg) was monitored for 31 yr from 1972 to 2002 in a 6000-ha watershed at Fulton County, Illinois, where the Metropolitan Water Reclamation District of Greater Chicago was restoring the productivity of strip-mined land using biosolids. The mean cumulative loading rates during the past 31 yr were 875 dry Mg ha(-1) for 1120-ha fields in the biosolids-amended watershed and 4.3 dry Mg ha(-1) for the 670-ha fields in the control watershed. Biosolids were injected into mine spoil fields as liquid fertilizer from 1972 to 1985, and incorporated as dewatered cake from 1980 to 1996 and air-dried solids from 1987 to 2002. The mean annual loadings of nutrients and trace elements from biosolids in 1 ha were 735 kg N, 530 kg P, 4.5 kg Cd, 30.7 kg Cu, and 0.11 kg Hg in the fields of the biosolids-amended watershed, and negligible in the fields of the control watershed. Sampling of surface water was conducted monthly in the 1970s, and three times per year in the 1980s and 1990s. The water samples were collected from 12 reservoirs and 2 creeks receiving drainage from the fields in the control watershed, and 8 reservoirs and 4 creeks associated with the fields in the biosolids-amended watershed for the analysis of NO3- -N (including NO2- N), NH4+-N, and total P, Cd, Cu, and Hg. Compared to the control (0.18 mg L(-1)), surface water NO3- -N in the biosolids-amended watershed (2.23 mg L(-1)) was consistently higher; however, it was still below the Illinois limit of 10 mg L(-1) for public and food-processing water supplies. Biosolids applications had a significant effect on mean concentrations of ammonium N (0.11 mg L(-1) for control and 0.24 mg L(-1) for biosolids) and total P (0.10 mg L(-1) for control and 0.16 mg L(-1) for biosolids) in

  15. Evaluation of Methods for Decladding LWR Fuel for a Pyroprocessing-Based Reprocessing Plant

    DTIC Science & Technology

    1992-10-01

    Liiz 00 zz 00 LAi 0 F-.. 1 0VI V) I. C0 5 7 t AL.11 Fig. 2. Westinghouse PWR fuel assembly. (Source: Westinghouse Electric Company Information...Brochure.) 6 photograph of a Westinghouse PWR fuel assembly. Decladding systems for the LWR- Actinide Recycle (LWR-AR) plant under study will have as a...types, the thickness of the cladding ranges from 0.03 to 0.037 in. 2. Zircaloy-4. This cladding material is used in PWR fuel rods and has as its

  16. Review of literature on the TMI accident and correlation to the LWR Safety Technology Program

    SciTech Connect

    Miller, W.J.

    1980-05-01

    This report is the result of approximately two man-months of effort devoted to assimilating and comprehending significant publicly available material related to Three Mile Island Unit 2 and events during and subsequent to the accident experienced on March 28, 1979. Those events were then correlated with the Preliminary LWR Safety Technology Program Plan (Preliminary Program Plan) prepared for the US Department of Energy by Sandia National Lab. This report is being submitted simultaneously with the SAI report entitled Preliminary Prioritization of Tasks in the Draft LWR Safety Technology Program Plan.

  17. Improvements and applications of COBRA-TF for stand-alone and coupled LWR safety analyses

    SciTech Connect

    Avramova, M.; Cuervo, D.

    2006-07-01

    The advanced thermal-hydraulic subchannel code COBRA-TF has been recently improved and applied for stand-alone and coupled LWR core calculations at the Pennsylvania State Univ. in cooperation with AREVA NP GmbH (Germany)) and the Technical Univ. of Madrid. To enable COBRA-TF for academic and industrial applications including safety margins evaluations and LWR core design analyses, the code programming, numerics, and basic models were revised and substantially improved. The code has undergone through an extensive validation, verification, and qualification program. (authors)

  18. Analysis of the Reuse of Uranium Recovered from the Reprocessing of Commercial LWR Spent Fuel

    SciTech Connect

    DelCul, Guillermo Daniel; Trowbridge, Lee D; Renier, John-Paul; Ellis, Ronald James; Williams, Kent Alan; Spencer, Barry B; Collins, Emory D

    2009-02-01

    This report provides an analysis of the factors involved in the reuse of uranium recovered from commercial light-water-reactor (LWR) spent fuels (1) by reenrichment and recycling as fuel to LWRs and/or (2) by recycling directly as fuel to heavy-water-reactors (HWRs), such as the CANDU (registered trade name for the Canadian Deuterium Uranium Reactor). Reuse is an attractive alternative to the current Advanced Fuel Cycle Initiative (AFCI) Global Nuclear Energy Partnership (GNEP) baseline plan, which stores the reprocessed uranium (RU) for an uncertain future or attempts to dispose of it as 'greater-than-Class C' waste. Considering that the open fuel cycle currently deployed in the United States already creates a huge excess quantity of depleted uranium, the closed fuel cycle should enable the recycle of the major components of spent fuel, such as the uranium and the hazardous, long-lived transuranic (TRU) actinides, as well as the managed disposal of fission product wastes. Compared with the GNEP baseline scenario, the reuse of RU in the uranium fuel cycle has a number of potential advantages: (1) avoidance of purchase costs of 11-20% of the natural uranium feed; (2) avoidance of disposal costs for a large majority of the volume of spent fuel that is reprocessed; (3) avoidance of disposal costs for a portion of the depleted uranium from the enrichment step; (4) depending on the {sup 235}U assay of the RU, possible avoidance of separative work costs; and (5) a significant increase in the production of {sup 238}Pu due to the presence of {sup 236}U, which benefits somewhat the transmutation value of the plutonium and also provides some proliferation resistance.

  19. Water chemistry in 179 randomly selected Swedish headwater streams related to forest production, clear-felling and climate.

    PubMed

    Löfgren, Stefan; Fröberg, Mats; Yu, Jun; Nisell, Jakob; Ranneby, Bo

    2014-12-01

    From a policy perspective, it is important to understand forestry effects on surface waters from a landscape perspective. The EU Water Framework Directive demands remedial actions if not achieving good ecological status. In Sweden, 44 % of the surface water bodies have moderate ecological status or worse. Many of these drain catchments with a mosaic of managed forests. It is important for the forestry sector and water authorities to be able to identify where, in the forested landscape, special precautions are necessary. The aim of this study was to quantify the relations between forestry parameters and headwater stream concentrations of nutrients, organic matter and acid-base chemistry. The results are put into the context of regional climate, sulphur and nitrogen deposition, as well as marine influences. Water chemistry was measured in 179 randomly selected headwater streams from two regions in southwest and central Sweden, corresponding to 10 % of the Swedish land area. Forest status was determined from satellite images and Swedish National Forest Inventory data using the probabilistic classifier method, which was used to model stream water chemistry with Bayesian model averaging. The results indicate that concentrations of e.g. nitrogen, phosphorus and organic matter are related to factors associated with forest production but that it is not forestry per se that causes the excess losses. Instead, factors simultaneously affecting forest production and stream water chemistry, such as climate, extensive soil pools and nitrogen deposition, are the most likely candidates The relationships with clear-felled and wetland areas are likely to be direct effects.

  20. Groundwater, Surface-Water, and Water-Chemistry Data, Black Mesa Area, Northeastern Arizona - 2007-2008

    USGS Publications Warehouse

    Macy, Jamie P.

    2009-01-01

    The N aquifer is an extensive aquifer and the primary source of groundwater in the 5,400-square-mile Black Mesa area in northeastern Arizona. Availability of water is an important issue in northeastern Arizona because of continued water requirements for industrial and municipal use by a growing population and because of low precipitation in the arid climate of the Black Mesa area, which is typically about 6 to 14 inches per year. The U.S. Geological Survey water-monitoring program in the Black Mesa area began in 1971 and provides information about the long-term effects of groundwater withdrawals from the N aquifer for industrial and municipal uses. This report presents results of data collected as part of the monitoring program in the Black Mesa area from January 2007 to September 2008. The monitoring program includes measurements of (1) groundwater withdrawals, (2) groundwater levels, (3) spring discharge, (4) surface-water discharge, and (5) groundwater chemistry. In 2007, total groundwater withdrawals were 4,270 acre-feet, industrial withdrawals were 1,170 acre-ft, and municipal withdrawals were 3,100 acre-ft. Total withdrawals during 2007 were about 41 percent less than total withdrawals in 2005. From 2006 to 2007, however, total withdrawals increased by 4 percent, industrial withdrawals decreased by approximately 2 percent, and total municipal withdrawals increased by 7 percent. From 2007 to 2008, annually measured water levels in the Black Mesa area declined in 6 of 11 wells measured in the unconfined areas of the N aquifer, and the median change was -0.2 feet. Water levels declined in 9 of 18 wells measured in the confined area of the aquifer. The median change for the confined area of the aquifer was -0.2 feet. From the prestress period (prior to 1965) to 2008, the median water-level change for 33 wells in both the confined and unconfined area was -12.9 feet. Median water-level changes were -1.0 feet for 15 wells measured in the unconfined areas and -33

  1. Revealing charge-transfer effects in gas-phase water chemistry.

    PubMed

    Cappelletti, David; Ronca, Enrico; Belpassi, Leonardo; Tarantelli, Francesco; Pirani, Fernando

    2012-09-18

    An understanding of the interactions involving water and other small hydrogenated molecules such as H(2)S and NH(3) at the molecular level is an important and elusive scientific goal with potential implications for fields ranging from biochemistry to astrochemistry. One longstanding question about water's intermolecular interactions, and notably hydrogen bonding, is the extent and importance of charge transfer (CT) , which can have important implications for the development of reliable model potentials for water chemistry, among other applications. The weakly bound adducts, commonly regarded as pure van der Waals systems, formed by H(2)O, H(2)S, and NH(3) with noble gases or simple molecules such as H(2), provide an interesting case study for these interactions. Their binding energies are approximately 1 or 2 kJ/mol at most, and CT effects in these systems are thought to be negligible. Our laboratory has performed high-resolution molecular-beam scattering experiments that probe the (absolute scale) intermolecular potential of various types of these gas-phase binary complexes with extreme sensitivity. These experiments have yielded surprising and intriguing quantitative results. The key experimental measurable is the "glory" quantum interference shift that shows a systematic, anomalous energy stabilization for the water complexes and clearly points to a significant role for CT effects. To investigate these findings, we have performed very accurate theoretical calculations and devised a simple approach to study the electron displacement that accompanies gas-phase binary intermolecular interactions in extreme detail. These calculations are based on a partial progressive integration of the electron density changes. The results unambiguously show that water's intermolecular interactions are not typical van der Waals complexes. Instead, these interactions possess a definite, strongly stereospecific CT component, even when very weak, where a water molecule may act as

  2. Effects of alloy chemistry, cold work, and water chemistry on corrosion fatigue and stress corrosion cracking of nickel alloys and welds.

    SciTech Connect

    Chopra, O. K.; Soppet, W. K.; Shack, W. J.; Energy Technology

    2001-04-01

    Reactor vessel internal components made of nickel-base alloys are susceptible to environmentally assisted cracking (EAC). A better understanding of the causes and mechanisms of this cracking may permit less conservative estimates of damage accumulation and requirements on inspection intervals. The objective of this work is to evaluate and compare the resistance of Alloys 600 and 690 and their welds, such as Alloys 82, 182, 52, and 152, to EAC in simulated light water reactor environments. The existing crack growth rate (CGR) data for these alloys under cyclic and constant loads have been evaluated to establish the effects of alloy chemistry, cold work, and water chemistry. The experimental fatigue CGRs are compared with CGRs that would be expected in air under the same mechanical loading conditions to obtain a qualitative understanding of the degree and range of conditions for significant environmental enhancement in growth rates. The existing stress corrosion cracking (SCC) data on Alloys 600 and 690 and Alloy 82, 182, and 52 welds have been compiled and analyzed to determine the influence of key parameters on growth rates in simulated PWR and BWR environments. The SCC data for these alloys have been evaluated with correlations developed by Scott and by Ford and Andresen.

  3. Variability of Water Chemistry in Tundra Lakes, Petuniabukta Coast, Central Spitsbergen, Svalbard

    PubMed Central

    Mazurek, Małgorzata; Paluszkiewicz, Renata; Rachlewicz, Grzegorz; Zwoliński, Zbigniew

    2012-01-01

    Samples of water from small tundra lakes located on raised marine terraces on the eastern coast of Petuniabukta (Ebbadalen, Central Spitsbergen) were examined to assess the changes in water chemistry that had occurred during the summer seasons of 2001–2003 and 2006. The unique environmental conditions of the study region include the predominance of sedimentary carbonate and sulphate rocks, low precipitation values, and an active permafrost layer with a maximum thickness of 1.2 m. The average specific electric conductivity (EC) values for the three summer seasons in the four lakes ranged from 242 to 398 μS cm−1. The highest EC values were observed when the air temperature decreased and an ice cover formed (cryochemical effects). The ion composition was dominated by calcium (50.7 to 86.6%), bicarbonates (39.5 to 86.4%), and sulphate anions. The high concentrations of HCO3 −, SO4 2−, and Ca2+ ions were attributed to the composition of the bedrock, which mainly consists of gypsum and anhydrite. The average proportion of marine components in the total load found in the Ebbadalen tundra lake waters was estimated to be 8.1%. Precipitation supplies sulphates (as much as 69–81%) and chlorides (14–36%) of nonsea origin. The chief source of these compounds may be contamination from the town of Longyearbyen. Most ions originate in the crust, the active layer of permafrost, but some are atmospheric in origin and are either transported or generated in biochemical processes. The concentrations of most components tend to increase during the summer months, reaching a maximum during freezing and partially precipitating onto the bottom sediments. PMID:22654629

  4. Long-term trends of water chemistry in mountain streams in Sweden - slow recovery from acidification

    NASA Astrophysics Data System (ADS)

    Borg, H.; Sundbom, M.

    2013-08-01

    The water chemistry of streams and precipitation in the province of Jämtland, northern Sweden has been monitored since the 1980s to study long-term trends, occurrence of acid episodes, and effects of liming. The acidity and sulphur in precipitation increased in the 1970s, followed by a loss of ANC and low pH in the streams. Sulphur deposition begun to decrease in the 1980s, until approximately 2000, after which the decrease levelled out. The stream water sulphate followed the precipitation trend but decreased more slowly and since the late 1990s a subtle increase was observed. The sulphate concentrations in the snow have generally been higher than or equal to the stream sulphate levels. Since 2005, stream sulphate has sometimes exceeded snow sulphate, indicating desorption of stored soil sulphate, possibly because of climate related changes in run-off routes through the soil profiles, following shorter periods of frost. Up to 2000, TOC increased by approximately 0.1 mg L-1 yr-1. The mean trends in sulphate and TOC from approximately 1990 until today are generally opposite. Acidic episodes with pH 4.0 at flow peaks occurred frequently in the unlimed streams, despite relatively well buffered waters at base flow. To evaluate the main causes for the loss of ANC, the changes in major ions during high flow were calculated. The most important contribution resulted from dilution of base cations, with contribution from organic anions. Sulphate also had some influence, as it was somewhat enriched or only slightly diluted during high flow. Wetland liming started in 1985 after which the earlier observed extreme peak values of Fe, Mn and Al, did not return. The studied area is remote from emission sources in Europe, but the critical load of acidity is still exceeded. The long-term recovery observed in the unlimed streams is thus slow, and severe acidic episodes still occur.

  5. Monitoring surface water chemistry near magnesium chloride dust suppressant treated roads in Colorado.

    PubMed

    Goodrich, Betsy A; Koski, Ronda D; Jacobi, William R

    2009-01-01

    Magnesium chloride (MgCl2)-based dust suppression products are commonly used throughout western United States on nonpaved roads for dust suppression and road stabilization by federal, state, and county transportation agencies. The environmental implications of annually applying these products throughout spring and summer months on adjacent stream chemistry are not known. Sixteen streams were monitored biweekly for 1 to 2 yr in two Colorado counties for a suite of water quality variables up and downstream of nonpaved roads treated with MgCl2-based dust suppression products. Eight of 16 streams had significantly higher downstream than upstream concentrations of chloride or magnesium over the entire monitoring period (pwater toward the stream and yearly amount of MgCl2 applied (R2=0.75, 0.51 and 0.49, respectively), indicating that road managers can limit the amount of product entering roadside streams by assessing drainage characteristics and application rates in best management practices. Although MgCl2-based dust suppressants did move into some roadside streams, the concentrations detected were below those reported to adversely affect fresh water aquatic organisms, but the ultimate fate of these ions in Colorado waterbodies are not known.

  6. Seasonal dynamics of water and air chemistry in an indoor chlorinated swimming pool.

    PubMed

    Zare Afifi, Mehrnaz; Blatchley, Ernest R

    2015-01-01

    Although swimming is known to be beneficial in terms of cardiovascular health, as well as for some forms of rehabilitation, swimming is also known to present risks to human health, largely in the form of exposure to microbial pathogens and disinfection byproducts (DBPs). Relatively little information is available in the literature to characterize the seasonal dynamics of air and water chemistry in indoor chlorinated swimming pools. To address this issue, water samples were collected five days per week from an indoor chlorinated swimming pool facility at a high school during the academic year and once per week during summer over a fourteen-month period. The samples were analyzed for free and combined chlorine, urea, volatile DBPs, pH, temperature and total alkalinity. Membrane Introduction Mass Spectrometry (MIMS) was used to identify and measure the concentrations of eleven aqueous-phase volatile DBPs. Variability in the concentrations of these DBPs was observed. Factors that influenced variability included bather loading and mixing by swimmers. These compounds have the ability to adversely affect water and air quality and human health. A large fraction of the existing literature regarding swimming pool air quality has focused on trichloramine (NCl₃). For this work, gas-phase NCl₃ was analyzed by an air sparging-DPD/KI method. The results showed that gas-phase NCl₃ concentration is influenced by bather loading and liquid-phase NCl₃ concentration. Urea is the dominant organic-N compound in human urine and sweat, and is known to be an important precursor for producing NCl₃ in swimming pools. Results of daily measurements of urea indicated a link between bather load and urea concentration in the pool.

  7. Application, chemistry, and environmental implications of contaminant-immobilization amendments on agricultural soil and water quality.

    PubMed

    Udeigwe, Theophilus K; Eze, Peter N; Teboh, Jasper M; Stietiya, Mohammed H

    2011-01-01

    Contaminants such as nitrogen (N), phosphorus (P), dissolved organic carbon (DOC), arsenic (As), heavy metals, and infectious pathogens are often associated with agricultural systems. Various soil and water remediation techniques including the use of chemical amendments have been employed to reduce the risks associated with these contaminants. This paper reviews the use of chemical amendments for immobilizing principal agricultural contaminants, the chemistry of contaminant immobilization, and the environmental consequences associated with the use of these chemical products. The commonly used chemical amendments were grouped into aluminum-, calcium-, and iron-containing products. Other products of interest include phosphorus-containing compounds and silicate clays. Mechanisms of contaminant immobilization could include one or a combination of the following: surface precipitation, adsorption to mineral surfaces (ion exchange and formation of stable complexes), precipitation as salts, and co-precipitation. The reaction pH, redox potential, clay minerals, and organic matter are potential factors that could control contaminant-immobilization processes. Reviews of potential environmental implications revealed that undesirable substances such as trace elements, fluoride, sulfate, total dissolved solids, as well as radioactive materials associated with some industrial wastes used as amendment could be leached to ground water or lost through runoff to receiving water bodies. The acidity or alkalinity associated with some of the industrial-waste amendments could also constitute a substantial environmental hazard. Chemical amendments could introduce elements capable of inducing or affecting the activities of certain lithotrophic microbes that could influence vital geochemical processes such as mineral dissolution and formation, weathering, and organic matter mineralization. Published by Elsevier Ltd.

  8. Pore water chemistry reveals gradients in mineral transformation across a model basaltic hillslope

    NASA Astrophysics Data System (ADS)

    Pohlmann, Michael; Dontsova, Katerina; Root, Robert; Ruiz, Joaquin; Troch, Peter; Chorover, Jon

    2016-06-01

    The extent of weathering incongruency during soil formation from rock controls local carbon and nutrient cycling in ecosystems, as well as the evolution of hydrologic flow paths. Prior studies of basalt weathering, including those that have quantified the dynamics of well-mixed, bench-scale laboratory reactors or characterized the structure and integrated response of field systems, indicate a strong influence of system scale on weathering rate and trajectory. For example, integrated catchment response tends to produce lower weathering rates than do well mixed reactors, but the mechanisms underlying these disparities remain unclear. Here we present pore water geochemistry and physical sensor data gathered during two controlled rainfall-runoff events on a large-scale convergent model hillslope mantled with 1 m uniform depth of granular basaltic porous media. The dense sampler and sensor array (1488 samplers and sensors embedded in 330 m3 of basalt) showed that rainfall-induced dissolution of basaltic glass produced supersaturation of pore waters with respect to multiple secondary solids including allophane, gibbsite, ferrihydrite, birnessite and calcite. The spatial distribution of saturation state was heterogeneous, suggesting an accumulation of solutes leading to precipitation of secondary solids along hydrologic flow paths. Rapid dissolution of primary silicates was widespread throughout the entire hillslope, irrespective of up-gradient flowpath length. However, coherent spatial variations in solution chemistry and saturation indices were observed in depth profiles and between distinct topographic regions of the hillslope. Colloids (110-2000 nm) enriched in iron (Fe), aluminum (Al), and phosphorus (P) were mobile in soil pore waters.

  9. Variability of water chemistry in Tundra Lakes, Petuniabukta Coast, Central Spitsbergen, Svalbard.

    PubMed

    Mazurek, Małgorzata; Paluszkiewicz, Renata; Rachlewicz, Grzegorz; Zwoliński, Zbigniew

    2012-01-01

    Samples of water from small tundra lakes located on raised marine terraces on the eastern coast of Petuniabukta (Ebbadalen, Central Spitsbergen) were examined to assess the changes in water chemistry that had occurred during the summer seasons of 2001-2003 and 2006. The unique environmental conditions of the study region include the predominance of sedimentary carbonate and sulphate rocks, low precipitation values, and an active permafrost layer with a maximum thickness of 1.2 m. The average specific electric conductivity (EC) values for the three summer seasons in the four lakes ranged from 242 to 398 μS cm(-1). The highest EC values were observed when the air temperature decreased and an ice cover formed (cryochemical effects). The ion composition was dominated by calcium (50.7 to 86.6%), bicarbonates (39.5 to 86.4%), and sulphate anions. The high concentrations of HCO(3) (-), SO(4) (2-), and Ca(2+) ions were attributed to the composition of the bedrock, which mainly consists of gypsum and anhydrite. The average proportion of marine components in the total load found in the Ebbadalen tundra lake waters was estimated to be 8.1%. Precipitation supplies sulphates (as much as 69-81%) and chlorides (14-36%) of nonsea origin. The chief source of these compounds may be contamination from the town of Longyearbyen. Most ions originate in the crust, the active layer of permafrost, but some are atmospheric in origin and are either transported or generated in biochemical processes. The concentrations of most components tend to increase during the summer months, reaching a maximum during freezing and partially precipitating onto the bottom sediments.

  10. Extending dry storage of spent LWR fuel for 100 years.

    SciTech Connect

    Einziger, R. E.

    1998-12-16

    Because of delays in closing the back end of the fuel cycle in the U.S., there is a need to extend dry inert storage of spent fuel beyond its originally anticipated 20-year duration. Many of the methodologies developed to support initial licensing for 20-year storage should be able to support the longer storage periods envisioned. This paper evaluates the applicability of existing information and methodologies to support dry storage up to 100 years. The thrust of the analysis is the potential behavior of the spent fuel. In the USA, the criteria for dry storage of LWR spent fuel are delineated in 10 CFR 72 [1]. The criteria fall into four general categories: maintain subcriticality, prevent the release of radioactive material above acceptable limits, ensure that radiation rates and doses do not exceed acceptable levels, and maintain retrievability of the stored radioactive material. These criteria need to be considered for normal, off-normal, and postulated accident conditions. The initial safety analysis report submitted for licensing evaluated the fuel's ability to meet the requirements for 20 years. It is not the intent to repeat these calculations, but to look at expected behavior over the additional 80 years, during which the temperatures and radiation fields are lower. During the first 20 years, the properties of the components may change because of elevated temperatures, presence of moisture, effects of radiation, etc. During normal storage in an inert atmosphere, there is potential for the cladding mechanical properties to change due to annealing or interaction with cask materials. The emissivity of the cladding could also change due to storage conditions. If there is air leakage into the cask, additional degradation could occur through oxidation in breached rods, which could lead to additional fission gas release and enlargement of cladding breaches. Air in-leakage could also affect cover gas conductivity, cladding oxidation, emissivity changes, and

  11. Water quality, organic chemistry of sediment, and biological conditions of streams near an abandoned wood-preserving plant site at Jackson, Tennessee. Water resources investigations report

    SciTech Connect

    Bradfield, A.D.; Flexner, N.M.; Webster, D.A.

    1993-12-31

    An investigation of the water quality, organic chemistry of sediment, and biological conditions of streams near an abandoned wood-preserving plant site at Jackson, Tennessee, was conducted by the U.S. Geological Survey during December 1990. The objectives of the study were to assess the extent of possible contamination of water and adverse affects on biota in the streams resulting from creosote-related discharge originating of this Superfund site.

  12. Tundra fire alters stream water chemistry and benthic invertebrate communities, North Slope, Alaska

    NASA Astrophysics Data System (ADS)

    Allen, A. R.; Bowden, W. B.; Kling, G. W.; Schuett, E.; Kostrzewski, J. M.; Kolden Abatzoglou, C.; Findlay, R. H.

    2010-12-01

    Increased fire frequency and severity are potentially important consequences of climate change in high latitude ecosystems. The 2007 Anaktuvuk River fire, which burned from July until October, is the largest recorded tundra fire from Alaska's north slope (≈1,000 km2). The immediate effects of wildfire on water chemistry and biotic assemblages in tundra streams are heretofore unknown. We hypothesized that a tundra fire would increase inorganic nutrient inputs to P-limited tundra streams, increasing primary production and altering benthic macroinvertebrate community structure. We examined linkages among: 1) percentage of riparian zone and overall watershed vegetation burned, 2) physical, chemical and biological stream characteristics, and 3) macroinvertebrate communities in streams draining burned and unburned watersheds during the summers of 2008 and 2009. Streams in burned watersheds contained higher mean concentrations of soluble reactive phosphorus (SRP), ammonium (NH4+), and dissolved organic carbon (DOC). In contrast, stream nitrate (NO3-) concentrations were lower in burned watersheds. The net result was that the tundra fire did not affect concentrations of dissolved inorganic nitrogen (NH4+ + NO3-). In spite of increased SRP, benthic chlorophyll-a biomass was not elevated. Macroinvertebrate abundances were 1.5 times higher in streams draining burned watersheds; Chironomidae midges, Nematodes, and Nemoura stoneflies showed the greatest increases in abundance. Multivariate multiple regression identified environmental parameters associated with the observed changes in the macroinvertebrate communities. Since we identified stream latitude as a significant predictor variable, latitude was included in the model as a covariate. After removing the variation associated with latitude, 67.3 % of the variance in macroinvertebrate community structure was explained by a subset of 7 predictor variables; DOC, conductivity, mean temperature, NO3-, mean discharge, SRP and NH

  13. Using Water Chemistry to Characterize Chemical Weathering in the Critical Zone Observatory: Shale Hills Catchment (Central Pennsylvania, USA)

    NASA Astrophysics Data System (ADS)

    Jin, L.; Brantley, S.

    2008-12-01

    Shales are important in determining global fluxes of C, P and Pt-group elements as they are widely exposed at the Earth's surfaces. A critical zone observatory (CZO) to study the hydrology, geochemistry, ecology, and geomorphology is established at the Shale Hills catchment in central Pennsylvania to complete such intensive investigations on the Rose Hill shale. The Shale Hills is V-shaped and forested catchment, with slopes around 16-18%. The parent shales are comprised of primarily illite, quartz, and chlorite. The dominant chemical reactions in the soil profiles are dissolution of chlorite and illite to more stable kaolinite, with vermiculite and hydroxy interlayered vermiculite as intermediate phases. Depth to the bedrock in the catchment depends mainly on the landscape positions, with thinner soils observed at the ridge tops, and much thicker soils at the valley floors and topographically depressional areas. Previous hydrologic studies have included monitoring the soil moisture contents and modeling the water flow dynamics in the soil zones. Study areas were selected to investigate the propagation rates of the weathering front (the interface between intact bedrock and weathered material) with increasing complexity: fluid flow above the bedrock interface is largely 1D and vertical at ridgetop, downslope and 2D along a planar transect, and convergent downslope and 3D along a swale transect. Weekly soil waters were collected at these sites. Chemistry of soil waters and first-order streams is controlled by chemical weathering reactions with only little contribution from rainfall. Soil waters become more concentrated from the ridge top to valley floor, as mineral dissolution progresses. The depth variation of water chemistry is distinctively different among the sites, which is closely related to soil- texture controlled water flowpaths. The stream reflects mixing among soil waters of different chemistry (shallow versus deep), and also mixing of soil waters and

  14. Determination of the components of stormflow using water chemistry and environmental isotopes, Mattole River basin, California

    USGS Publications Warehouse

    Kennedy, V.C.; Kendall, C.; Zellweger, G.W.; Wyerman, T.A.; Avanzino, R.J.

    1986-01-01

    The chemical and isotopic composition of rainfall and stream water was monitored during a storm in the Mattole River basin of northwestern California. About 250 mm of rain fell during 6 days (???80% within a 42 h period) in late January, 1972, following 24 days of little or no precipitation. River discharge near Petrolia increased from 22 m3 s-1 to a maximum of 1300 m3 s-1 while chloride and silica concentrations decreased only from 3.2 to 2.1 and 11.5 to 8.6 mgl-1, respectively. Meanwhile, the isotopic composition of the river changed from ??D = - 42???, ??180 = - 6.8??? and 40 tritium units (T.U.) to extreme values at highest flow of ??D = - 35???, ??180 = - 5.9??? and 25 T.U. in response to volume-weighted rainfall averaging ??D = - 19.5???, ??180 = - 3.1??? and 18 T.U. Despite much rainfall of a composition quite different from that of the prestorm river water, "buffering" processes in the watershed greatly restricted changes in the chemical and isotopic content of the river during storm runoff. Because of the physical and hydrologic characteristics of the watershed, major contributions of groundwater to stormflow are very unlikely. The large increase in dissolved chemical load observed at maximum river discharge required that extensive interaction with, and presumably penetration of, soils occurred within a few hours time. Such a large increase in chemical load also required subsurface stormflow throughout a high proportion of the watershed. Chemical and isotopic stabilization of stormflow is believed to be due mainly to displacement of prestorm soil water, with some effects on river chemistry due to rapid rain-soil interactions. The isotopic and chemical composition of prestorm soil moisture cannot readily be predicted a priori because of possible variability in rainfall composition, evaporation, and exchange with atmospheric moisture, nor can it be assumed that baseflow has a predictable relation to the chemical or isotopic composition of water displaced

  15. Determination of the components of stormflow using water chemistry and environmental isotopes, Mattole River basin, California

    NASA Astrophysics Data System (ADS)

    Kennedy, V. C.; Kendall, Carol; Zellweger, G. W.; Wyerman, T. A.; Avanzino, R. J.

    1986-04-01

    The chemical and isotopic composition of rainfall and stream water was monitored during a storm in the Mattole River basin of northwestern California. About 250 mm of rain fell during 6 days (˜80% within a 42 h period) in late January, 1972, following 24 days of little or no precipitation. River discharge near Petrolia increased from 22 m 3 s -1 to a maximum of 1300 m 3 s -1 while chloride and silica concentrations decreased only from 3.2 to 2.1 and 11.5 to 8.6 mgl -1, respectively. Meanwhile, the isotopic composition of the river changed from δD = - 42‰, δ 180 = - 6.8‰ and 40 tritium units (T.U.) to extreme values at highest flow of δD = - 35‰, δ 180 = - 5.9‰ and 25 T.U. in response to volume-weighted rainfall averaging δD = - 19.5‰, δ 180 = - 3.1‰ and 18 T.U. Despite much rainfall of a composition quite different from that of the prestorm river water, "buffering" processes in the watershed greatly restricted changes in the chemical and isotopic content of the river during storm runoff. Because of the physical and hydrologic characteristics of the watershed, major contributions of groundwater to stormflow are very unlikely. The large increase in dissolved chemical load observed at maximum river discharge required that extensive interaction with, and presumably penetration of, soils occurred within a few hours time. Such a large increase in chemical load also required subsurface stormflow throughout a high proportion of the watershed. Chemical and isotopic stabilization of stormflow is believed to be due mainly to displacement of prestorm soil water, with some effects on river chemistry due to rapid rain-soil interactions. The isotopic and chemical composition of prestorm soil moisture cannot readily be predicted a priori because of possible variability in rainfall composition, evaporation, and exchange with atmospheric moisture, nor can it be assumed that baseflow has a predictable relation to the chemical or isotopic composition of water

  16. The impact of integrated water management on the Space Station propulsion system

    NASA Technical Reports Server (NTRS)

    Schmidt, George R.

    1987-01-01

    The water usage of elements in the Space Station integrated water system (IWS) is discussed, and the parameters affecting the overall water balance and the water-electrolysis propulsion-system requirements are considered. With nominal IWS operating characteristics, extra logistic water resupply (LWR) is found to be unnecessary in the satisfaction of the nominal propulsion requirements. With the consideration of all possible operating characteristics, LWR will not be required in 65.5 percent of the cases, and for 17.9 percent of the cases LWR can be eliminated by controlling the stay time of theShuttle Orbiter orbiter.

  17. Chesapeake Bay earth science study: interstitial water chemistry-chemical zonation, tributaries study, and trace metals. Final report

    SciTech Connect

    Hill, J.M.; Blakeslee, P.J.; Conkwright, R.D.; McKeon, G.

    1982-11-01

    The sediments of the Chesapeake Bay constitute a large reservoir of chemical species derived from natural and anthropogenic sources. The behavior of these materials in the estuary is determined by the physiochemical sedimentary environments in which they are found. Three major environments are identified, from the interstitial water chemistry as Northern Bay, Middle Bay, and Southern Bay. The chemical sedimentary environments of five tributaries to the main Bay were sampled for interstitial water. The data indicate the concentration of the metals are greater than coastal seawater and river water, and comparable to concentrations found in municipal waste.

  18. Ground-Water, Surface-Water, and Water-Chemistry Data, Black Mesa Area, Northeastern Arizona--2004-05

    DTIC Science & Technology

    2006-02-27

    aquifer, Black Mesa area, Arizona, 2004 …………………………………… 7 Figure 5. MAp showing water-level changes in N aquifer wells from the prestress period to 2005...area, Arizona, 2004 ……………………………………………………………………… 8 Table 4. Withdrawals from the N aquifer by water-use category for 1965-2004 and for other periods ...Black Mesa, Arizona …………………………………………… 8 Table 5. Water-level changes in wells completed in the N aquifer, Black Mesa area, Arizona, prestress period

  19. Water chemistry used in the secondary coolant circuit of unit 3 at the rovno nuclear power station involving correction treatment of working m