WorldWideScience

Sample records for biogeochemical process evaluation

  1. Coupled Biogeochemical Process Evaluation for Conceptualizing Trichloroethylene Co-Metabolism

    Energy Technology Data Exchange (ETDEWEB)

    Rick Colwell; Corey Radtke; Mark Delwiche; Deborah Newby; Lynn Petzke; Mark Conrad; Eoin Brodie; Hope Lee; Bob Starr; Dana Dettmers; Ron Crawford; Andrzej Paszczynski; Nick Bernardini; Ravi Paidisetti; Tonia Green

    2006-06-01

    Chlorinated solvent wastes (e.g., trichloroethene or TCE) often occur as diffuse subsurface plumes in complex geological environments where coupled processes must be understood in order to implement remediation strategies. Monitored natural attenuation (MNA) warrants study as a remediation technology because it minimizes worker and environment exposure to the wastes and because it costs less than other technologies. However, to be accepted MNA requires different ?lines of evidence? indicating that the wastes are effectively destroyed. We are studying the coupled biogeochemical processes that dictate the rate of TCE co-metabolism first in the medial zone (TCE concentration: 1,000 to 20,000 ?g/L) of a plume at the Idaho National Laboratory?s Test Area North (TAN) site and then at Paducah or the Savannah River Site. We will use flow-through in situ reactors (FTISR) to investigate the rate of methanotrophic co-metabolism of TCE and the coupling of the responsible biological processes with the dissolved methane flux and groundwater flow velocity. TCE co-metabolic rates at TAN are being assessed and interpreted in the context of enzyme activity, gene expression, and cellular inactivation related to intermediates of TCE co-metabolism. By determining the rate of TCE co-metabolism at different groundwater flow velocities, we will derive key modeling parameters for the computational simulations that describe the attenuation, and thereby refine such models while assessing the contribution of microbial co-metabolism relative to other natural attenuation processes. This research will strengthen our ability to forecast the viability of MNA at DOE and other sites contaminated with chlorinated hydrocarbons.

  2. A Unified Multi-scale Model for Cross-Scale Evaluation and Integration of Hydrological and Biogeochemical Processes

    Science.gov (United States)

    Liu, C.; Yang, X.; Bailey, V. L.; Bond-Lamberty, B. P.; Hinkle, C.

    2013-12-01

    Mathematical representations of hydrological and biogeochemical processes in soil, plant, aquatic, and atmospheric systems vary with scale. Process-rich models are typically used to describe hydrological and biogeochemical processes at the pore and small scales, while empirical, correlation approaches are often used at the watershed and regional scales. A major challenge for multi-scale modeling is that water flow, biogeochemical processes, and reactive transport are described using different physical laws and/or expressions at the different scales. For example, the flow is governed by the Navier-Stokes equations at the pore-scale in soils, by the Darcy law in soil columns and aquifer, and by the Navier-Stokes equations again in open water bodies (ponds, lake, river) and atmosphere surface layer. This research explores whether the physical laws at the different scales and in different physical domains can be unified to form a unified multi-scale model (UMSM) to systematically investigate the cross-scale, cross-domain behavior of fundamental processes at different scales. This presentation will discuss our research on the concept, mathematical equations, and numerical execution of the UMSM. Three-dimensional, multi-scale hydrological processes at the Disney Wilderness Preservation (DWP) site, Florida will be used as an example for demonstrating the application of the UMSM. In this research, the UMSM was used to simulate hydrological processes in rooting zones at the pore and small scales including water migration in soils under saturated and unsaturated conditions, root-induced hydrological redistribution, and role of rooting zone biogeochemical properties (e.g., root exudates and microbial mucilage) on water storage and wetting/draining. The small scale simulation results were used to estimate effective water retention properties in soil columns that were superimposed on the bulk soil water retention properties at the DWP site. The UMSM parameterized from smaller

  3. An evaluation of physical and biogeochemical processes regulating perennial suboxic conditions in the water column of the Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Sarma, V.V.S.S.

    that oxygen minimum zone (OMZ) in the Arabian Sea is regulated largely by physical processes in association with biogeochemical cycling of oxygen. This results in perennial suboxic conditions in the water column with no significant seasonal variability...

  4. Final Progress Report: Coupled Biogeochemical Process Evaluation for Conceptualizing Trichloroethylene Cometabolism

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, Ronald L; Paszczynski, Andrzej J

    2010-02-19

    Our goal within the overall project is to demonstrate the presence and abundance of methane monooxygenases (MMOs) enzymes and their genes within the microbial community of the Idaho National Laboratory (INL) Test Area North (TAN) site. MMOs are thought to be the primary catalysts of natural attenuation of trichloroethylene (TCE) in contaminated groundwater at this location. The actual presence of the proteins making up MMO complexes would provide direct evidence for its participation in TCE degradation. The quantitative estimation of MMO genes and their translation products (sMMO and pMMO proteins) and the knowledge about kinetics and substrate specificity of MMOs will be used to develop mathematical models of the natural attenuation process in the TAN aquifer. The model will be particularly useful in prediction of TCE degradation rate in TAN and possibly in the other DOE sites. Bacteria known as methanotrophs produce a set of proteins that assemble to form methane monooxygenase complexes (MMOs), enzymes that oxidize methane as their natural substrate, thereby providing a carbon and energy source for the organisms. MMOs are also capable of co-metabolically transforming chlorinated solvents like TCE into nontoxic end products such as carbon dioxide and chloride. There are two known forms of methane monooxygenase, a membrane-bound particulate form (pMMO) and a cytoplasmic soluble form (sMMO). pMMO consists of two components, pMMOH (a hydroxylase comprised of 47-, 27-, and 24-kDa subunits) and pMMOR (a reductase comprised of 63 and 8-kDa subunits). sMMO consists of three components: a hydroxylase (protein A-250 kDa), a dimer of three subunits (α2β2γ2), a regulatory protein (protein B-15.8 kDa), and a reductase (protein C-38.6 kDa). All methanotrophs will produce a methanol dehydrogenase to channel the product of methane oxidation (methanol) into the central metabolite formaldehyde. University of Idaho (UI) efforts focused on proteomic analyses using mass

  5. Diel biogeochemical processes in terrestrial waters

    Science.gov (United States)

    Nimick, David A.; Gammons, Christopher H.

    2011-01-01

    Many biogeochemical processes in rivers and lakes respond to the solar photocycle and produce persistent patterns of measureable phenomena that exhibit a day–night, or 24-h, cycle. Despite a large body of recent literature, the mechanisms responsible for these diel fluctuations are widely debated, with a growing consensus that combinations of physical, chemical, and biological processes are involved. These processes include streamflow variation, photosynthesis and respiration, plant assimilation, and reactions involving photochemistry, adsorption and desorption, and mineral precipitation and dissolution. Diel changes in streamflow and water properties such as temperature, pH, and dissolved oxygen concentration have been widely recognized, and recently, diel studies have focused more widely by considering other constituents such as dissolved and particulate trace metals, metalloids, rare earth elements, mercury, organic matter, dissolved inorganic carbon (DIC), and nutrients. The details of many diel processes are being studied using stable isotopes, which also can exhibit diel cycles in response to microbial metabolism, photosynthesis and respiration, or changes in phase, speciation, or redox state. In addition, secondary effects that diel cycles might have, for example, on biota or in the hyporheic zone are beginning to be considered.This special issue is composed primarily of papers presented at the topical session “Diurnal Biogeochemical Processes in Rivers, Lakes, and Shallow Groundwater” held at the annual meeting of the Geological Society of America in October 2009 in Portland, Oregon. This session was organized because many of the growing number of diel studies have addressed just a small part of the full range of diel cycling phenomena found in rivers and lakes. This limited focus is understandable because (1) fundamental aspects of many diel processes are poorly understood and require detailed study, (2) the interests and expertise of individual

  6. Hyporheic zone as a bioreactor: sediment heterogeneity influencing biogeochemical processes

    Science.gov (United States)

    Perujo, Nuria; Romani, Anna M.; Sanchez-Vila, Xavier

    2017-04-01

    Mediterranean fluvial systems are characterized by frequent periods of low flow or even drought. During low flow periods, water from wastewater treatment plants (WWTPs) is proportionally large in fluvial systems. River water might be vertically transported through the hyporheic zone, and then porous medium acts as a complementary treatment system since, as water infiltrates, a suite of biogeochemical processes occurs. Subsurface sediment heterogeneity plays an important role since it influences the interstitial fluxes of the medium and drives biomass growing, determining biogeochemical reactions. In this study, WWTP water was continuously infiltrated for 3 months through two porous medium tanks: one consisting of 40 cm of fine sediment (homogeneous); and another comprised of two layers of different grain size sediments (heterogeneous), 20 cm of coarse sediment in the upper part and 20 cm of fine one in the bottom. Several hydrological, physicochemical and biological parameters were measured periodically (weekly at the start of the experiment and biweekly at the end). Analysed parameters include dissolved nitrogen, phosphorus, organic carbon, and oxygen all measured at the surface, and at 5, 20 and 40 cm depth. Variations in hydraulic conductivity with time were evaluated. Sediment samples were also analysed at three depths (surface, 20 and 40 cm) to determine bacterial density, chlorophyll content, extracellular polymeric substances, and biofilm function (extracellular enzyme activities and carbon substrate utilization profiles). Preliminary results suggest hydraulic conductivity to be the main driver of the differences in the biogeochemical processes occurring in the subsurface. At the heterogeneous tank, a low nutrient reduction throughout the whole medium is measured. In this medium, high hydraulic conductivity allows for a large amount of infiltrating water, but with a small residence time. Since some biological processes are largely time-dependent, small water

  7. Biogeochemical Processes Regulating the Mobility of Uranium in Sediments

    Energy Technology Data Exchange (ETDEWEB)

    Belli, Keaton M.; Taillefert, Martial

    2016-07-01

    This book chapters reviews the latest knowledge on the biogeochemical processes regulating the mobility of uranium in sediments. It contains both data from the literature and new data from the authors.

  8. Wetland biogeochemical processes and simulation modeling

    Science.gov (United States)

    Bai, Junhong; Huang, Laibin; Gao, Haifeng; Jia, Jia; Wang, Xin

    2018-02-01

    As the important landscape with rich biodiversity and high productivity, wetlands can provide numerous ecological services including playing an important role in regulating global biogeochemical cycles, filteringpollutants from terrestrial runoff and atmospheric deposition, protecting and improving water quality, providing living habitats for plants and animals, controlling floodwaters, and retaining surface water flow during dry periods (Reddy and DeLaune, 2008; Qin and Mitsch, 2009; Zhao et al., 2016). However, more than 50% of the world's wetlands had been altered, degraded or lost through a wide range of human activities in the past 150 years, and only a small percentage of the original wetlands remained around the world after over two centuries of intensive development and urbanization (O'connell, 2003; Zhao et al., 2016).

  9. The effect of biogeochemical processes on pH

    NARCIS (Netherlands)

    Soetaert, K.E.R.; Hofmann, A.F.; Middelburg, J.J.; Meysman, F.J.R.; Greenwood, J.E.

    2007-01-01

    The impact of biogeochemical and physical processes on aquatic chemistry is usually expressed in terms of alkalinity. Here we show how to directly calculate the effect of single processes on pH. Under the assumptions of equilibrium and electroneutrality, the rate of change of pH can be calculated as

  10. Extracellular Electron Transport Coupling Biogeochemical Processes Centimeters

    DEFF Research Database (Denmark)

    Risgaard-Petersen, Nils; Fossing, Henrik; Christensen, Peter Bondo

    2010-01-01

    Recent observations in marine sediment have revealed  conductive networks transmitting electrons from oxidation processes in the anoxic zone to oxygen reduction in the oxiczone [1]. The electrochemical processes and conductors seem to be biologically controlled and may account for more than half...

  11. Biogeochemical processes in the northern Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Gaye-Haake, B.; Guptha, M.V.S.; Murty, V.S.N.; Ittekkot, V.

    in the northern Indian Ocean’’, and from national research programs of India and Germany con- ducted as a contribution to the international JGOFS Process Study in the Arabian Sea. Addi- tional contributions cover research carried out within India’s Polymetallic... of coccolithophorids in addition to organic carbon and carbonate con- centrations and accumulation rates for a 200ka record Prabhu and Shankar show that glacial stages 2,4 and 6 have had higher productivities in the eastern Arabian Sea at about 151N. They, moreover...

  12. Biogeochemical redox processes and their impact on contaminant dynamics

    Science.gov (United States)

    Borch, Thomas; Kretzschmar, Ruben; Kappler, Andreas; Van Cappellen, Philippe; Ginder-Vogel, Matthew; Campbell, Kate M.

    2010-01-01

    Life and element cycling on Earth is directly related to electron transfer (or redox) reactions. An understanding of biogeochemical redox processes is crucial for predicting and protecting environmental health and can provide new opportunities for engineered remediation strategies. Energy can be released and stored by means of redox reactions via the oxidation of labile organic carbon or inorganic compounds (electron donors) by microorganisms coupled to the reduction of electron acceptors including humic substances, iron-bearing minerals, transition metals, metalloids, and actinides. Environmental redox processes play key roles in the formation and dissolution of mineral phases. Redox cycling of naturally occurring trace elements and their host minerals often controls the release or sequestration of inorganic contaminants. Redox processes control the chemical speciation, bioavailability, toxicity, and mobility of many major and trace elements including Fe, Mn, C, P, N, S, Cr, Cu, Co, As, Sb, Se, Hg, Tc, and U. Redox-active humic substances and mineral surfaces can catalyze the redox transformation and degradation of organic contaminants. In this review article, we highlight recent advances in our understanding of biogeochemical redox processes and their impact on contaminant fate and transport, including future research needs.

  13. South Florida wetlands ecosystem; biogeochemical processes in peat

    Science.gov (United States)

    Orem, William; ,

    1996-01-01

    The South Florida wetlands ecosystem is an environment of great size and ecological diversity (figs. 1 and 2). The landscape diversity and subtropical setting of this ecosystem provide a habitat for an abundance of plants and wildlife, some of which are unique to South Florida. South Florida wetlands are currently in crisis, however, due to the combined effects of agriculture, urbanization, and nearly 100 years of water management. Serious problems facing this ecosystem include (1) phosphorus contamination producing nutrient enrichment, which is causing changes in the native vegetation, (2) methylmercury contamination of fish and other wildlife, which poses a potential threat to human health, (3) changes in the natural flow of water in the region, resulting in more frequent drying of wetlands, loss of organic soils, and a reduction in freshwater flow to Florida Bay, (4) hypersalinity, massive algal blooms, and seagrass loss in parts of Florida Bay, and (5) a decrease in wildlife populations, especially those of wading birds. This U.S. Geological Survey (USGS) project focuses on the role of organic-rich sediments (peat) of South Florida wetlands in regulating the concentrations and impact of important chemical species in the environment. The cycling of carbon, nitrogen, phosphorus, and sulfur in peat is an important factor in the regulation of water quality in the South Florida wetlands ecosystem. These elements are central to many of the contamination issues facing South Florida wetlands, such as nutrient enrichment, mercury toxicity, and loss of peat. Many important chemical and biological reactions occur in peat and control the fate of chemical species in wetlands. Wetland scientists often refer to these reactions as biogeochemical processes, because they are chemical reactions usually mediated by microorganisms in a geological environment. An understanding of the biogeochemical processes in peat of South Florida wetlands will provide a basis for evaluating the

  14. Microbial Metagenomics Reveals Climate-Relevant Subsurface Biogeochemical Processes.

    Science.gov (United States)

    Long, Philip E; Williams, Kenneth H; Hubbard, Susan S; Banfield, Jillian F

    2016-08-01

    Microorganisms play key roles in terrestrial system processes, including the turnover of natural organic carbon, such as leaf litter and woody debris that accumulate in soils and subsurface sediments. What has emerged from a series of recent DNA sequencing-based studies is recognition of the enormous variety of little known and previously unknown microorganisms that mediate recycling of these vast stores of buried carbon in subsoil compartments of the terrestrial system. More importantly, the genome resolution achieved in these studies has enabled association of specific members of these microbial communities with carbon compound transformations and other linked biogeochemical processes-such as the nitrogen cycle-that can impact the quality of groundwater, surface water, and atmospheric trace gas concentrations. The emerging view also emphasizes the importance of organism interactions through exchange of metabolic byproducts (e.g., within the carbon, nitrogen, and sulfur cycles) and via symbioses since many novel organisms exhibit restricted metabolic capabilities and an associated extremely small cell size. New, genome-resolved information reshapes our view of subsurface microbial communities and provides critical new inputs for advanced reactive transport models. These inputs are needed for accurate prediction of feedbacks in watershed biogeochemical functioning and their influence on the climate via the fluxes of greenhouse gases, CO2, CH4, and N2O. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Temporal dynamics of biogeochemical processes at the Norman Landfill site

    Science.gov (United States)

    Arora, Bhavna; Mohanty, Binayak P.; McGuire, Jennifer T.; Cozzarelli, Isabelle M.

    2013-01-01

    The temporal variability observed in redox sensitive species in groundwater can be attributed to coupled hydrological, geochemical, and microbial processes. These controlling processes are typically nonstationary, and distributed across various time scales. Therefore, the purpose of this study is to investigate biogeochemical data sets from a municipal landfill site to identify the dominant modes of variation and determine the physical controls that become significant at different time scales. Data on hydraulic head, specific conductance, δ2H, chloride, sulfate, nitrate, and nonvolatile dissolved organic carbon were collected between 1998 and 2000 at three wells at the Norman Landfill site in Norman, OK. Wavelet analysis on this geochemical data set indicates that variations in concentrations of reactive and conservative solutes are strongly coupled to hydrologic variability (water table elevation and precipitation) at 8 month scales, and to individual eco-hydrogeologic framework (such as seasonality of vegetation, surface-groundwater dynamics) at 16 month scales. Apart from hydrologic variations, temporal variability in sulfate concentrations can be associated with different sources (FeS cycling, recharge events) and sinks (uptake by vegetation) depending on the well location and proximity to the leachate plume. Results suggest that nitrate concentrations show multiscale behavior across temporal scales for different well locations, and dominant variability in dissolved organic carbon for a closed municipal landfill can be larger than 2 years due to its decomposition and changing content. A conceptual framework that explains the variability in chemical concentrations at different time scales as a function of hydrologic processes, site-specific interactions, and/or coupled biogeochemical effects is also presented.

  16. Hyporheic flow and transport processes: mechanisms, models, and biogeochemical implications

    Science.gov (United States)

    Boano, Fulvio; Harvey, Judson W.; Marion, Andrea; Packman, Aaron I.; Revelli, Roberto; Ridolfi, Luca; Anders, Wörman

    2014-01-01

    Fifty years of hyporheic zone research have shown the important role played by the hyporheic zone as an interface between groundwater and surface waters. However, it is only in the last two decades that what began as an empirical science has become a mechanistic science devoted to modeling studies of the complex fluid dynamical and biogeochemical mechanisms occurring in the hyporheic zone. These efforts have led to the picture of surface-subsurface water interactions as regulators of the form and function of fluvial ecosystems. Rather than being isolated systems, surface water bodies continuously interact with the subsurface. Exploration of hyporheic zone processes has led to a new appreciation of their wide reaching consequences for water quality and stream ecology. Modern research aims toward a unified approach, in which processes occurring in the hyporheic zone are key elements for the appreciation, management, and restoration of the whole river environment. In this unifying context, this review summarizes results from modeling studies and field observations about flow and transport processes in the hyporheic zone and describes the theories proposed in hydrology and fluid dynamics developed to quantitatively model and predict the hyporheic transport of water, heat, and dissolved and suspended compounds from sediment grain scale up to the watershed scale. The implications of these processes for stream biogeochemistry and ecology are also discussed."

  17. Development of interactive graphic user interfaces for modeling reaction-based biogeochemical processes in batch systems with BIOGEOCHEM

    Science.gov (United States)

    Chang, C.; Li, M.; Yeh, G.

    2010-12-01

    The BIOGEOCHEM numerical model (Yeh and Fang, 2002; Fang et al., 2003) was developed with FORTRAN for simulating reaction-based geochemical and biochemical processes with mixed equilibrium and kinetic reactions in batch systems. A complete suite of reactions including aqueous complexation, adsorption/desorption, ion-exchange, redox, precipitation/dissolution, acid-base reactions, and microbial mediated reactions were embodied in this unique modeling tool. Any reaction can be treated as fast/equilibrium or slow/kinetic reaction. An equilibrium reaction is modeled with an implicit finite rate governed by a mass action equilibrium equation or by a user-specified algebraic equation. A kinetic reaction is modeled with an explicit finite rate with an elementary rate, microbial mediated enzymatic kinetics, or a user-specified rate equation. None of the existing models has encompassed this wide array of scopes. To ease the input/output learning curve using the unique feature of BIOGEOCHEM, an interactive graphic user interface was developed with the Microsoft Visual Studio and .Net tools. Several user-friendly features, such as pop-up help windows, typo warning messages, and on-screen input hints, were implemented, which are robust. All input data can be real-time viewed and automated to conform with the input file format of BIOGEOCHEM. A post-processor for graphic visualizations of simulated results was also embedded for immediate demonstrations. By following data input windows step by step, errorless BIOGEOCHEM input files can be created even if users have little prior experiences in FORTRAN. With this user-friendly interface, the time effort to conduct simulations with BIOGEOCHEM can be greatly reduced.

  18. Final Project Report - Coupled Biogeochemical Process Evaluation for Conceptualizing Trichloriethylene Co-Metabolism: Co-Metabolic Enzyme Activity Probes and Modeling Co-Metabolism and Attenuation

    Energy Technology Data Exchange (ETDEWEB)

    Starr, Robert C; Orr, Brennon R; Lee, M Hope; Delwiche, Mark

    2010-02-26

    Trichloroethene (TCE) (also known as trichloroethylene) is a common contaminant in groundwater. TCE is regulated in drinking water at a concentration of 5 µg/L, and a small mass of TCE has the potential to contaminant large volumes of water. The physical and chemical characteristics of TCE allow it to migrate quickly in most subsurface environments, and thus large plumes of contaminated groundwater can form from a single release. The migration and persistence of TCE in groundwater can be limited by biodegradation. TCE can be biodegraded via different processes under either anaerobic or aerobic conditions. Anaerobic biodegradation is widely recognized, but aerobic degradation is less well recognized. Under aerobic conditions, TCE can be oxidized to non hazardous conditions via cometabolic pathways. This study applied enzyme activity probes to demonstrate that cometabolic degradation of TCE occurs in aerobic groundwater at several locations, used laboratory microcosm studies to determine aerobic degradation rates, and extrapolated lab-measured rates to in situ rates based on concentrations of microorganisms with active enzymes involved in cometabolic TCE degradation. Microcosms were constructed using basalt chips that were inoculated with microorganisms to groundwater at the Idaho National Laboratory Test Area North TCE plume by filling a set of Flow-Through In Situ Reactors (FTISRs) with chips and placing the FTISRs into the open interval of a well for several months. A parametric study was performed to evaluate predicted degradation rates and concentration trends using a competitive inhibition kinetic model, which accounts for competition for enzyme active sites by both a growth substrate and a cometabolic substrate. The competitive inhibition kinetic expression was programmed for use in the RT3D reactive transport package. Simulations of TCE plume evolution using both competitive inhibition kinetics and first order decay were performed.

  19. An evaluation of physical and biogeochemical processes regulating the oxygen minimum zone in the water column of the Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Sarma, V.V.S.S.

    of the biological processes. The inconsistency observed among oxygen consumption rates derived based on the present oxygen budget, carbon regeneration rate, and oxygen consumption rates computed based on electron transport system technique could be due to inadequate...

  20. Silicon biogeochemical processes in a large river (Cauvery, India)

    Science.gov (United States)

    Kameswari Rajasekaran, Mangalaa; Arnaud, Dapoigny; Jean, Riotte; Sarma Vedula, V. S. S.; Nittala, S. Sarma; Sankaran, Subramanian; Gundiga Puttojirao, Gurumurthy; Keshava, Balakrishna; Cardinal, Damien

    2016-04-01

    Silicon (Si), one of the key nutrients for diatom growth in ocean, is principally released during silicate weathering on continents and then exported by rivers. Phytoplankton composition is determined by the availability of Si relative to other nutrients, mainly N and P, which fluxes in estuarine and coastal systems are affected by eutrophication due to land use and industrialization. In order to understand the biogeochemical cycle of Si and its supply to the coastal ocean, we studied a tropical monsoonal river from Southern India (Cauvery) and compare it with other large and small rivers. Cauvery is the 7th largest river in India with a basin covering 85626 sq.km. The major part of the basin (˜66%) is covered by agriculture and inhabited by more than 30 million inhabitants. There are 96 dams built across the basin. As a consequence, 80% of the historical discharge is diverted, mainly for irrigation (Meunier et al. 2015). This makes the Cauvery River a good example of current anthropogenic pressure on silicon biogeochemical cycle. We measured amorphous silica contents (ASi) and isotopic composition of dissolved silicon (δ30Si-DSi) in the Cauvery estuary, including freshwater end-member and groundwater as well as along a 670 km transect along the river course. Other Indian rivers and estuaries have also been measured, including some less impacted by anthropogenic pressure. The average Cauvery δ30Si signature just upstream the estuary is 2.21±0.15 ‰ (n=3) which is almost 1‰ heavier than the groundwater isotopic composition (1.38±0.03). The δ30Si-DSi of Cauvery water is also almost 1‰ heavier than the world river supply to the ocean estimated so far and 0.4‰ heavier than other large Indian rivers like Ganges (Frings et al 2015) and Krishna. On the other hand, the smaller watersheds (Ponnaiyar, Vellar, and Penna) adjacent to Cauvery also display heavy δ30Si-DSi. Unlike the effect of silicate weathering, the heavy isotopic compositions in the river

  1. International Workshop on Biogeochemical Processes in the Northern Indian Ocean: Notes

    Digital Repository Service at National Institute of Oceanography (India)

    Guptha, M.V.S.

    , several International Conferences were conducted, among them ICSU (International Council of Scientific Unions) - SCOPE (Scientific Committee on Problems of the Environment) Workshops on "Particle flux in the Oceans" in 1991 (Goa) and 1993 (Hamburg...-1 NOTES INTERNATIONAL WORKSHOP ON BIOGEOCHEMICAL PROCESSES IN THE NORTHERN INDIAN OCEAN An International Workshop on Biogeochemical Processes in the Northern Indian Ocean was jointly . organized by the National Institute of Oceanography (NIO, CSIR), India...

  2. Diel biogeochemical processes and their effect on the aqueous chemistry of streams: A review

    Science.gov (United States)

    Nimick, David A.; Gammons, Christopher H.; Parker, Stephen R.

    2011-01-01

    This review summarizes biogeochemical processes that operate on diel, or 24-h, time scales in streams and the changes in aqueous chemistry that are associated with these processes. Some biogeochemical processes, such as those producing diel cycles of dissolved O2 and pH, were the first to be studied, whereas processes producing diel concentration cycles of a broader spectrum of chemical species including dissolved gases, dissolved inorganic and organic carbon, trace elements, nutrients, stable isotopes, and suspended particles have received attention only more recently. Diel biogeochemical cycles are interrelated because the cyclical variations produced by one biogeochemical process commonly affect another. Thus, understanding biogeochemical cycling is essential not only for guiding collection and interpretation of water-quality data but also for geochemical and ecological studies of streams. Expanded knowledge of diel biogeochemical cycling will improve understanding of how natural aquatic environments function and thus lead to better predictions of how stream ecosystems might react to changing conditions of contaminant loading, eutrophication, climate change, drought, industrialization, development, and other factors.

  3. Can spectroscopic analysis improve our understanding of biogeochemical processes in agricultural streams?

    Science.gov (United States)

    Bieroza, Magdalena; Heathwaite, Ann Louise

    2015-04-01

    In agricultural catchments diffuse fluxes of nutrients, mainly nitrogen (N) and phosphorus (P) from arable land and livestock are responsible for pollution of receiving waters and their eutrophication. Organic matter (OM) can play an important role in mediating a range of biogeochemical processes controlling diffuse pollution in streams and at their interface with surrounding land in the riparian and hyporheic zones. Thus, a holistic and simultaneous monitoring of N, P and OM fractions can help to improve our understanding of biogeochemical functioning of agricultural streams. In this study we build on intensive in situ monitoring of diffuse pollution in a small agricultural groundwater-fed stream in NW England carried out since 2009. The in situ monitoring unit captures high-frequency (15 minutes to hourly) responses of water quality parameters including total phosphorus, total reactive phosphorus and nitrate-nitrogen to changing flow conditions. For two consecutive hydrological years we have carried out additional spectroscopic water analyses to characterise organic matter components and their interactions with nutrient fractions. Automated and grab water samples have been analysed using ultraviolet-visible (UV-Vis) absorbance and excitation-emission (EEM) fluorescence spectroscopy. In addition, a tryptophan sensor was trialled to capture in situ fluorescence dynamics. Our paper evaluates patterns in nutrient and OM responses to baseflow and storm flow conditions and provides an assessment of storage-related changes of automated samples and temperature and turbidity effects on in situ tryptophan measurements. The paper shows the value of spectroscopic measurements to understand biogeochemical and hydrological nutrient dynamics and quantifies analytical uncertainty associated with both laboratory-based and in situ spectroscopic measurements.

  4. Modelling of transport and biogeochemical processes in pollution plumes: Literature review of model development

    DEFF Research Database (Denmark)

    Brun, A.; Engesgaard, Peter Knudegaard

    2002-01-01

    A literature survey shows how biogeochemical (coupled organic and inorganic reaction processes) transport models are based on considering the complete biodegradation process as either a single- or as a two-step process. It is demonstrated that some two-step process models rely on the Partial Equi....... A second paper [J. Hydrol. 256 (2002) 230-249], reports the application of the model to a field study of biogeochemical transport processes in a landfill plume in Denmark (Vejen). (C) 2002 Elsevier Science B.V. All rights reserved....

  5. Investigations of coupled biogeochemical processes affecting the transformation of U: Integration of synchrotron-based approaches

    International Nuclear Information System (INIS)

    Ken Kemner; Ed O'Loughlin

    2007-01-01

    The summary of this paper is that: (1) An improved understanding of fundamental coupled biogeochemical processes obviously is critical for decision making for environmental remediation and long-term stewardship. (2) Synchrotron x-ray radiation provides the most versatile and powerful approach for directly determining the chemical speciation of the radionuclide and heavy metal contaminants of concern to DOE. (3) Integration of synchrotron approaches with integrated multidisciplinary scientific investigations provides a powerful way of understanding coupled biogeochemical processes whereby the scientific question drives the development of new synchrotron-based technologies and the unique information provided by the synchrotron-based technology enables the development of new scientific hypotheses and insights

  6. Functional Enzyme-Based Approach for Linking Microbial Community Functions with Biogeochemical Process Kinetics

    Energy Technology Data Exchange (ETDEWEB)

    Li, Minjing [School; Qian, Wei-jun [Pacific Northwest National Laboratory, Richland, Washington 99354, United States; Gao, Yuqian [Pacific Northwest National Laboratory, Richland, Washington 99354, United States; Shi, Liang [School; Liu, Chongxuan [Pacific Northwest National Laboratory, Richland, Washington 99354, United States; School

    2017-09-28

    The kinetics of biogeochemical processes in natural and engineered environmental systems are typically described using Monod-type or modified Monod-type models. These models rely on biomass as surrogates for functional enzymes in microbial community that catalyze biogeochemical reactions. A major challenge to apply such models is the difficulty to quantitatively measure functional biomass for constraining and validating the models. On the other hand, omics-based approaches have been increasingly used to characterize microbial community structure, functions, and metabolites. Here we proposed an enzyme-based model that can incorporate omics-data to link microbial community functions with biogeochemical process kinetics. The model treats enzymes as time-variable catalysts for biogeochemical reactions and applies biogeochemical reaction network to incorporate intermediate metabolites. The sequences of genes and proteins from metagenomes, as well as those from the UniProt database, were used for targeted enzyme quantification and to provide insights into the dynamic linkage among functional genes, enzymes, and metabolites that are necessary to be incorporated in the model. The application of the model was demonstrated using denitrification as an example by comparing model-simulated with measured functional enzymes, genes, denitrification substrates and intermediates

  7. Modelling of transport and biogeochemical processes in pollution plumes: Vejen landfill, Denmark

    DEFF Research Database (Denmark)

    Brun, A.; Engesgaard, Peter Knudegaard; Christensen, Thomas Højlund

    2002-01-01

    A biogeochemical transport code is used to simulate leachate attenuation. biogeochemical processes. and development of redox zones in a pollution plume downstream of the Vejen landfill in Denmark. Calibration of the degradation parameters resulted in a good agreement with the observed distribution...... redox zone were determined giving DOC half-lives ranging from 100 to 1-2 days going from the methanogenic to the aerobic zone. The order of decrease in DOC half-lives from the anaerobic to the aerobic zone corresponds to findings at other landfills. (C) 2002 Elsevier Science B.V. All rights reserved....

  8. Development of Advanced Eco-hydrologic and Biogeochemical Coupling Model to Re-evaluate Greenhouse Gas Budget of Biosphere

    Science.gov (United States)

    Nakayama, T.; Maksyutov, S. S.

    2015-12-01

    Inland waters including rivers, lakes, and groundwater are suggested to act as a transport pathway for water and dissolved substances, and play some role in continental biogeochemical cycling (Cole et al., 2007; Battin et al., 2009). The authors have developed process-based National Integrated Catchment-based Eco-hydrology (NICE) model (2014, 2015, etc.), which includes feedback between hydrologic-geomorphic-ecological processes. In this study, NICE was further developed to couple with various biogeochemical cycle models in biosphere, those for water quality in aquatic ecosystems, and those for carbon weathering. The NICE-biogeochemical coupling model incorporates connectivity of the biogeochemical cycle accompanied by hydrologic cycle between surface water and groundwater, hillslopes and river networks, and other intermediate regions. The model also includes reaction between inorganic and organic carbons, and its relation to nitrogen and phosphorus in terrestrial-aquatic continuum. The coupled model showed to improve the accuracy of inundation stress mechanism such as photosynthesis and primary production, which attributes to improvement of CH4 flux in wetland sensitive to fluctuations of shallow groundwater. The model also simulated CO2 evasion from inland water in global scale, and was relatively in good agreement in empirical relation (Aufdenkampe et al., 2011) which has relatively an uncertainty in the calculated flux because of pCO2 data missing in some region and effect of small tributaries, etc. Further, the model evaluated how the expected CO2 evasion might change as inland waters become polluted with nutrients and eutrophication increases from agriculture and urban areas (Pacheco et al., 2013). This advanced eco-hydrologic and biogeochemical coupling model would play important role to re-evaluate greenhouse gas budget of the biosphere, and to bridge gap between top-down and bottom-up approaches (Battin et al., 2009; Regnier et al., 2013).

  9. Isotope biogeochemical assessment of natural biodegradation processes in open cast pit mining landscapes

    Science.gov (United States)

    Jeschke, Christina; Knöller, Kay; Koschorreck, Matthias; Ussath, Maria; Hoth, Nils

    2014-05-01

    In Germany, a major share of the energy production is based on the burning of lignite from open cast pit mines. The remediation and re-cultivation of the former mining areas in the Lusatian and Central German lignite mining district is an enormous technical and economical challenge. After mine closures, the surrounding landscapes are threatened by acid mine drainage (AMD), i.e. the acidification and mineralization of rising groundwater with metals and inorganic contaminants. The high content of sulfur (sulfuric acid, sulfate), nitrogen (ammonium) and iron compounds (iron-hydroxides) deteriorates the groundwater quality and decelerates sustainable development of tourism in (former) mining landscapes. Natural biodegradation or attenuation (NA) processes of inorganic contaminants are considered to be a technically low impact and an economically beneficial solution. The investigations of the stable isotope compositions of compounds involved in NA processes helps clarify the dynamics of natural degradation and provides specific informations on retention processes of sulfate and nitrogen-compounds in mine dump water, mine dump sediment, and residual pit lakes. In an active mine dump we investigated zones where the process of bacterial sulfate reduction, as one very important NA process, takes place and how NA can be enhanced by injecting reactive substrates. Stable isotopes signatures of sulfur and nitrogen components were examined and evaluated in concert with hydrogeochemical data. In addition, we delineated the sources of ammonium pollution in mine dump sediments and investigated nitrification by 15N-labeling techniques to calculate the limit of the conversion of harmful ammonium to nitrate in residual mining lakes. Ultimately, we provided an isotope biogeochemical assessment of natural attenuation of sulfate and ammonium at mine dump sites and mining lakes. Also, we estimated the risk potential for water in different compartments of the hydrological system. In

  10. Do antibiotics have environmental side-effects? Impact of synthetic antibiotics on biogeochemical processes.

    Science.gov (United States)

    Roose-Amsaleg, Céline; Laverman, Anniet M

    2016-03-01

    Antibiotic use in the early 1900 vastly improved human health but at the same time started an arms race of antibiotic resistance. The widespread use of antibiotics has resulted in ubiquitous trace concentrations of many antibiotics in most environments. Little is known about the impact of these antibiotics on microbial processes or "non-target" organisms. This mini-review summarizes our knowledge of the effect of synthetically produced antibiotics on microorganisms involved in biogeochemical cycling. We found only 31 articles that dealt with the effects of antibiotics on such processes in soil, sediment, or freshwater. We compare the processes, antibiotics, concentration range, source, environment, and experimental approach of these studies. Examining the effects of antibiotics on biogeochemical processes should involve environmentally relevant concentrations (instead of therapeutic), chronic exposure (versus acute), and monitoring of the administered antibiotics. Furthermore, the lack of standardized tests hinders generalizations regarding the effects of antibiotics on biogeochemical processes. We investigated the effects of antibiotics on biogeochemical N cycling, specifically nitrification, denitrification, and anammox. We found that environmentally relevant concentrations of fluoroquinolones and sulfonamides could partially inhibit denitrification. So far, the only documented effects of antibiotic inhibitions were at therapeutic doses on anammox activities. The most studied and inhibited was nitrification (25-100 %) mainly at therapeutic doses and rarely environmentally relevant. We recommend that firm conclusions regarding inhibition of antibiotics at environmentally relevant concentrations remain difficult due to the lack of studies testing low concentrations at chronic exposure. There is thus a need to test the effects of these environmental concentrations on biogeochemical processes to further establish the possible effects on ecosystem functioning.

  11. Modeling biogeochemical processes of phosphorus for global food supply.

    Science.gov (United States)

    Dumas, Marion; Frossard, Emmanuel; Scholz, Roland W

    2011-08-01

    Harvests of crops, their trade and consumption, soil erosion, fertilization and recycling of organic waste generate fluxes of phosphorus in and out of the soil that continuously change the worldwide spatial distribution of total phosphorus in arable soils. Furthermore, due to variability in the properties of the virgin soils and the different histories of agricultural practices, on a planetary scale, the distribution of total soil phosphorus is very heterogeneous. There are two key relationships that determine how this distribution and its change over time affect crop yields. One is the relationship between total soil phosphorus and bioavailable soil phosphorus and the second is the relationship between bioavailable soil phosphorus and yields. Both of these depend on environmental variables such as soil properties and climate. We propose a model in which these relationships are described probabilistically and integrated with the dynamic feedbacks of P cycling in the human ecosystem. The model we propose is a first step towards evaluating the large-scale effects of different nutrient management scenarios. One application of particular interest is to evaluate the vulnerability of different regions to an increased scarcity in P mineral fertilizers. Another is to evaluate different regions' deficiency in total soil phosphorus compared with the level at which they could sustain their maximum potential yield without external mineral inputs of phosphorus but solely by recycling organic matter to close the nutrient cycle. Copyright © 2011 Elsevier Ltd. All rights reserved.

  12. Ecosystem services and biogeochemical cycles on a global scale: valuation of water, carbon and nitrogen processes

    International Nuclear Information System (INIS)

    Watanabe, Marcos D.B.; Ortega, Enrique

    2011-01-01

    Ecosystem services (ES) are provided by healthy ecosystems and are fundamental to support human life. However, natural systems have been degraded all over the world and the process of degradation is partially attributed to the lack of knowledge regarding the economic benefits associated with ES, which usually are not captured in the market. To valuate ES without using conventional approaches, such as the human's willingness-to-pay for ecosystem goods and services, this paper uses a different method based on Energy Systems Theory to estimate prices for biogeochemical flows that affect ecosystem services by considering their emergy content converted to equivalent monetary terms. Ecosystem services related to water, carbon and nitrogen biogeochemical flows were assessed since they are connected to a range of final ecosystem services including climate regulation, hydrological regulation, food production, soil formation and others. Results in this paper indicate that aquifer recharge, groundwater flow, carbon dioxide sequestration, methane emission, biological nitrogen fixation, nitrous oxide emission and nitrogen leaching/runoff are the most critical biogeochemical flows in terrestrial systems. Moreover, monetary values related to biogeochemical flows on a global scale could provide important information for policymakers concerned with payment mechanisms for ecosystem services and costs of greenhouse gas emissions.

  13. Hybrid numerical methods for multiscale simulations of subsurface biogeochemical processes

    International Nuclear Information System (INIS)

    Scheibe, T D; Tartakovsky, A M; Tartakovsky, D M; Redden, G D; Meakin, P

    2007-01-01

    Many subsurface flow and transport problems of importance today involve coupled non-linear flow, transport, and reaction in media exhibiting complex heterogeneity. In particular, problems involving biological mediation of reactions fall into this class of problems. Recent experimental research has revealed important details about the physical, chemical, and biological mechanisms involved in these processes at a variety of scales ranging from molecular to laboratory scales. However, it has not been practical or possible to translate detailed knowledge at small scales into reliable predictions of field-scale phenomena important for environmental management applications. A large assortment of numerical simulation tools have been developed, each with its own characteristic scale. Important examples include 1. molecular simulations (e.g., molecular dynamics); 2. simulation of microbial processes at the cell level (e.g., cellular automata or particle individual-based models); 3. pore-scale simulations (e.g., lattice-Boltzmann, pore network models, and discrete particle methods such as smoothed particle hydrodynamics); and 4. macroscopic continuum-scale simulations (e.g., traditional partial differential equations solved by finite difference or finite element methods). While many problems can be effectively addressed by one of these models at a single scale, some problems may require explicit integration of models across multiple scales. We are developing a hybrid multi-scale subsurface reactive transport modeling framework that integrates models with diverse representations of physics, chemistry and biology at different scales (sub-pore, pore and continuum). The modeling framework is being designed to take advantage of advanced computational technologies including parallel code components using the Common Component Architecture, parallel solvers, gridding, data and workflow management, and visualization. This paper describes the specific methods/codes being used at each

  14. Geo- and Biogeochemical Processes in a Heliothermal Hypersaline Lake

    Energy Technology Data Exchange (ETDEWEB)

    Zachara, John M.; Moran, James J.; Resch, Charles T.; Lindemann, Stephen R.; Felmy, Andrew R.; Bowden, Mark E.; Cory, Alexandra B.; Fredrickson, Jim K.

    2016-03-17

    exchange, and lower winter lake temperatures. Solubility calculations indicated seasonal biogenic and thermogenic aragonite precipitation in the upper and lower mixolimnion, but the absence of calcareous sediments at depth suggested dissolution and recycling during winter months. Carbon concentrations were high in Hot Lake (e.g., 0 to 450 mg/L for both DOC and DIC) and increased with depth. DIC concentrations were variable and influenced by calcium carbonate precipitation, but DOC concentrations remained constant except in the monimolimnion where mass loss by anaerobic microbial processes was implied. Biogenic reduced solutes originating in monimolimnion (H2S and CH4) appeared to be biologically oxidized in the metalimnion as they were not observed in more shallow lake waters. Multi-year solute inventory calculations indicated that Hot Lake is a stable, albeit seasonally and annually dynamic feature, with inorganic solutes cycled between lake waters and sediments depending on annual recharge, temperature, and lake water dilution state. Hot Lake with its extreme geochemical and thermal regime functions as analogue of early earth and extraterrestrial life environments.

  15. Coupling Between Overlying Hydrodynamics, Bioturbation, and Biogeochemical Processes Controls Metal Mobility, Bioavailability, and Toxicity in Sediments

    Science.gov (United States)

    2016-05-01

    communities, and posing ongoing threats to larger pelagic organisms by food web contamination .2 Sediment contamination is a major concern worldwide and has...structural heterogeneity, and biogeochemical processes controls contaminant mobility, bioavailability, and toxicity in sediments. American Geophysical...Controls Contaminant Mobility, Bioavailability, and Toxicity in Sediments 5a. CONTRACT NUMBER W912HQ-10-C-0024 5b. GRANT NUMBER 5c. PROGRAM ELEMENT

  16. Microbialites and microbial communities: Biological diversity, biogeochemical functioning, diagenetic processes, tracers of environmental changes

    OpenAIRE

    Camoin, Gilbert; Gautret, Pascale

    2006-01-01

    Editorial; This special issue is dedicated to microbialites and microbial communities and addresses their biological diversity, their biogeochemical functioning, their roles in diagenetic processes and their environmental significance. It is the logical successor of the special issue that one of us edited after the workshop on “Microbial mediation in carbonate diagenesis” which was held in Chichilianne (France) in 1997 (Camoin, G., Ed., 1999. Microbial mediation in carbonate diagenesis. Sedim...

  17. Reservoir and contaminated sediments impacts in high-Andean environments: Morphodynamic interactions with biogeochemical processes

    Science.gov (United States)

    Escauriaza, C. R.; Contreras, M. T.; Müllendorff, D. A.; Pasten, P.; Pizarro, G. E.

    2014-12-01

    Rapid changes due to anthropic interventions in high-altitude environments, such as the Altiplano region in South America, require new approaches to understand the connections between physical and biogeochemical processes. Alterations of the water quality linked to the river morphology can affect the ecosystems and human development in the long-term. The future construction of a reservoir in the Lluta river, located in northern Chile, will change the spatial distribution of arsenic-rich sediments, which can have significant effects on the lower parts of the watershed. In this investigation we develop a coupled numerical model to predict and evaluate the interactions between morphodynamic changes in the Lluta reservoir, and conditions that can potentially desorb arsenic from the sediments. Assuming that contaminants are mobilized under anaerobic conditions, we calculate the oxygen concentration within the sediments to study the interactions of the delta progradation with the potential arsenic release. This work provides a framework for future studies aimed to analyze the complex connections between morphodynamics and water quality, when contaminant-rich sediments accumulate in a reservoir. The tool can also help to design effective risk management and remediation strategies in these extreme environments. Research has been supported by Fondecyt grant 1130940 and CONICYT/FONDAP Grant 15110017

  18. Cyclic biogeochemical processes and nitrogen fate beneath a subtropical stormwater infiltration basin.

    Science.gov (United States)

    O'Reilly, Andrew M; Chang, Ni-Bin; Wanielista, Martin P

    2012-05-15

    A stormwater infiltration basin in north-central Florida, USA, was monitored from 2007 through 2008 to identify subsurface biogeochemical processes, with emphasis on N cycling, under the highly variable hydrologic conditions common in humid, subtropical climates. Cyclic variations in biogeochemical processes generally coincided with wet and dry hydrologic conditions. Oxidizing conditions in the subsurface persisted for about one month or less at the beginning of wet periods with dissolved O(2) and NO(3)(-) showing similar temporal patterns. Reducing conditions in the subsurface evolved during prolonged flooding of the basin. At about the same time O(2) and NO(3)(-) reduction concluded, Mn, Fe and SO(4)(2-) reduction began, with the onset of methanogenesis one month later. Reducing conditions persisted up to six months, continuing into subsequent dry periods until the next major oxidizing infiltration event. Evidence of denitrification in shallow groundwater at the site is supported by median NO(3)(-)-N less than 0.016 mg L(-1), excess N(2) up to 3 mg L(-1) progressively enriched in δ(15)N during prolonged basin flooding, and isotopically heavy δ(15)N and δ(18)O of NO(3)(-) (up to 25‰ and 15‰, respectively). Isotopic enrichment of newly infiltrated stormwater suggests denitrification was partially completed within two days. Soil and water chemistry data suggest that a biogeochemically active zone exists in the upper 1.4m of soil, where organic carbon was the likely electron donor supplied by organic matter in soil solids or dissolved in infiltrating stormwater. The cyclic nature of reducing conditions effectively controlled the N cycle, switching N fate beneath the basin from NO(3)(-) leaching to reduction in the shallow saturated zone. Results can inform design of functionalized soil amendments that could replace the native soil in a stormwater infiltration basin and mitigate potential NO(3)(-) leaching to groundwater by replicating the biogeochemical

  19. Application of a hybrid multiscale approach to simulate hydrologic and biogeochemical processes in the river-groundwater interaction zone.

    Energy Technology Data Exchange (ETDEWEB)

    Hammond, Glenn Edward; Yang, Xiaofan; Song, Xuehang; Song, Hyun-Seob; Hou, Zhangshuan; Chen, Xingyuan; Liu, Yuanyuan; Scheibe, Tim

    2017-03-01

    The groundwater-surface water interaction zone (GSIZ) plays an important role in riverine and watershed ecosystems as the exchange of waters of variable composition and temperature (hydrologic exchange flows) stimulate microbial activity and associated biogeochemical reactions. Variable temporal and spatial scales of hydrologic exchange flows, heterogeneity of the subsurface environment, and complexity of biogeochemical reaction networks in the GSIZ present challenges to incorporation of fundamental process representations and model parameterization across a range of spatial scales (e.g. from pore-scale to field scale). This paper presents a novel hybrid multiscale simulation approach that couples hydrologic-biogeochemical (HBGC) processes between two distinct length scales of interest.

  20. Biogeochemical processes on tree islands in the greater everglades: Initiating a new paradigm

    Science.gov (United States)

    Wetzel, P.R.; Sklar, Fred H.; Coronado, C.A.; Troxler, T.G.; Krupa, S.L.; Sullivan, P.L.; Ewe, S.; Price, R.M.; Newman, S.; Orem, W.H.

    2011-01-01

    Scientists' understanding of the role of tree islands in the Everglades has evolved from a plant community of minor biogeochemical importance to a plant community recognized as the driving force for localized phosphorus accumulation within the landscape. Results from this review suggest that tree transpiration, nutrient infiltration from the soil surface, and groundwater flow create a soil zone of confluence where nutrients and salts accumulate under the head of a tree island during dry periods. Results also suggest accumulated salts and nutrients are flushed downstream by regional water flows during wet periods. That trees modulate their environment to create biogeochemical hot spots and strong nutrient gradients is a significant ecological paradigm shift in the understanding of the biogeochemical processes in the Everglades. In terms of island sustainability, this new paradigm suggests the need for distinct dry-wet cycles as well as a hydrologic regime that supports tree survival. Restoration of historic tree islands needs further investigation but the creation of functional tree islands is promising. Copyright ?? 2011 Taylor & Francis Group, LLC.

  1. Lacustrine wetland in an agricultural catchment: nitrogen removal and related biogeochemical processes

    Directory of Open Access Journals (Sweden)

    R. Balestrini

    2008-03-01

    Full Text Available The role of specific catchment areas, such as the soil-river or lake interfaces, in removing or buffering the flux of N from terrestrial to aquatic ecosystems is globally recognized but the extreme variability of microbiological and hydrological processes make it difficult to predict the extent to which different wetlands function as buffer systems. In this paper we evaluate the degree to which biogeochemical processes in a lacustrine wetland are responsible for the nitrate removal from ground waters feeding Candia Lake (Northern Italy. A transect of 18 piezometers was installed perpendicular to the shoreline, in a sub-unit formed by 80 m of poplar plantation, close to a crop field and 30 m of reed swamp. The chemical analysis revealed a drastic NO3-N ground water depletion from the crop field to the lake, with concentrations decreasing from 15–18 mg N/l to the detection limit within the reeds. Patterns of Cl, SO42–, O2, NO2-N, HCO3 and DOC suggest that the metabolic activity of bacterial communities, based on the differential use of electron donors and acceptors in redox reactions is the key function of this system. The significant inverse relationship found between NO3-N and HCO3 is a valuable indicator of the denitrification activity. The pluviometric regime, the temperature, the organic carbon availability and the hydrogeomorphic properties are the main environmental factors affecting the N transformations in the studied lacustrine ecosystem.

  2. Urban pollution of sediments: Impact on the physiology and burrowing activity of tubificid worms and consequences on biogeochemical processes

    Energy Technology Data Exchange (ETDEWEB)

    Pigneret, M., E-mail: mathilde.pigneret@univ-lyon1.fr [LEHNA, UMR CNRS 5023, Ecologie des Hydrosystèmes Naturels et Anthropisés, Université de Lyon, Université Lyon 1, ENTPE, 6 rue Raphael Dubois, 69622 Villeurbanne (France); Mermillod-Blondin, F.; Volatier, L.; Romestaing, C. [LEHNA, UMR CNRS 5023, Ecologie des Hydrosystèmes Naturels et Anthropisés, Université de Lyon, Université Lyon 1, ENTPE, 6 rue Raphael Dubois, 69622 Villeurbanne (France); Maire, E.; Adrien, J. [MATEIS, UMR CNRS 5510, INSA de Lyon, 25 avenue Jean Capelle, 69621 Villeurbanne (France); Guillard, L.; Roussel, D.; Hervant, F. [LEHNA, UMR CNRS 5023, Ecologie des Hydrosystèmes Naturels et Anthropisés, Université de Lyon, Université Lyon 1, ENTPE, 6 rue Raphael Dubois, 69622 Villeurbanne (France)

    2016-10-15

    In urban areas, infiltration basins are designed to manage stormwater runoff from impervious surfaces and allow the settling of associated pollutants. The sedimentary layer deposited at the surface of these structures is highly organic and multicontaminated (mainly heavy metals and hydrocarbons). Only few aquatic species are able to maintain permanent populations in such an extreme environment, including the oligochaete Limnodrilus hoffmeisteri. Nevertheless, the impact of urban pollutants on these organisms and the resulting influence on infiltration basin functioning remain poorly studied. Thus, the aim of this study was to determine how polluted sediments could impact the survival, the physiology and the bioturbation activity of L. hoffmeisteri and thereby modify biogeochemical processes occurring at the water-sediment interface. To this end, we conducted laboratory incubations of worms, in polluted sediments from infiltration basins or slightly polluted sediments from a stream. Analyses were performed to evaluate physiological state and burrowing activity (X-ray micro-tomography) of worms and their influences on biogeochemical processes (nutrient fluxes, CO{sub 2} and CH{sub 4} degassing rates) during 30-day long experiments. Our results showed that worms exhibited physiological responses to cope with high pollution levels, including a strong ability to withstand the oxidative stress linked to contamination with heavy metals. We also showed that the presence of urban pollutants significantly increased the burrowing activity of L. hoffmeisteri, demonstrating the sensitivity and the relevance of such a behavioural response as biomarker of sediment toxicity. In addition, we showed that X-ray micro-tomography was an adequate technique for accurate and non-invasive three-dimensional investigations of biogenic structures formed by bioturbators. The presence of worms induced stimulations of nutrient fluxes and organic matter recycling (between + 100% and 200% of CO

  3. Volume reduction outweighs biogeochemical processes in controlling phosphorus treatment in aged detention systems

    Science.gov (United States)

    Shukla, Asmita; Shukla, Sanjay; Annable, Michael D.; Hodges, Alan W.

    2017-08-01

    Stormwater detention areas (SDAs) play an important role in treating end-of-the-farm runoff in phosphorous (P) limited agroecosystems. Phosphorus transport from the SDAs, including those through subsurface pathways, are not well understood. The prevailing understanding of these systems assumes that biogeochemical processes play the primary treatment role and that subsurface losses can be neglected. Water and P fluxes from a SDA located in a row-crop farm were measured for two years (2009-2011) to assess the SDA's role in reducing downstream P loads. The SDA treated 55% (497 kg) and 95% (205 kg) of the incoming load during Year 1 (Y1, 09-10) and Year 2 (Y2, 10-11), respectively. These treatment efficiencies were similar to surface water volumetric retention (49% in Y1 and 84% in Y2) and varied primarily with rainfall. Similar water volume and P retentions indicate that volume retention is the main process controlling P loads. A limited role of biogeochemical processes was supported by low to no remaining soil P adsorption capacity due to long-term drainage P input. The fact that outflow P concentrations (Y1 = 368.3 μg L- 1, Y2 = 230.4 μg L- 1) could be approximated by using a simple mixing of rainfall and drainage P input further confirmed the near inert biogeochemical processes. Subsurface P losses through groundwater were 304 kg (27% of inflow P) indicating that they are an important source for downstream P. Including subsurface P losses reduces the treatment efficiency to 35% (from 61%). The aboveground biomass in the SDA contained 42% (240 kg) of the average incoming P load suggesting that biomass harvesting could be a cost-effective alternative for reviving the role of biogeochemical processes to enhance P treatment in aged, P-saturated SDAs. The 20-year present economic value of P removal through harvesting was estimated to be 341,000, which if covered through a cost share or a payment for P treatment services program could be a positive outcome for both

  4. Targeted quantification of functional enzyme dynamics in environmental samples for microbially mediated biogeochemical processes: Targeted quantification of functional enzyme dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Li, Minjing [School of Environmental Studies, China University of Geosciences, Wuhan 430074 People' s Republic of China; Gao, Yuqian [Pacific Northwest National Laboratory, Richland, WA 99354 USA; Qian, Wei-Jun [Pacific Northwest National Laboratory, Richland, WA 99354 USA; Shi, Liang [Pacific Northwest National Laboratory, Richland, WA 99354 USA; Liu, Yuanyuan [Pacific Northwest National Laboratory, Richland, WA 99354 USA; Nelson, William C. [Pacific Northwest National Laboratory, Richland, WA 99354 USA; Nicora, Carrie D. [Pacific Northwest National Laboratory, Richland, WA 99354 USA; Resch, Charles T. [Pacific Northwest National Laboratory, Richland, WA 99354 USA; Thompson, Christopher [Pacific Northwest National Laboratory, Richland, WA 99354 USA; Yan, Sen [School of Environmental Studies, China University of Geosciences, Wuhan 430074 People' s Republic of China; Fredrickson, James K. [Pacific Northwest National Laboratory, Richland, WA 99354 USA; Zachara, John M. [Pacific Northwest National Laboratory, Richland, WA 99354 USA; Liu, Chongxuan [Pacific Northwest National Laboratory, Richland, WA 99354 USA; School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055 People' s Republic of China

    2017-07-13

    Microbially mediated biogeochemical processes are catalyzed by enzymes that control the transformation of carbon, nitrogen, and other elements in environment. The dynamic linkage between enzymes and biogeochemical species transformation has, however, rarely been investigated because of the lack of analytical approaches to efficiently and reliably quantify enzymes and their dynamics in soils and sediments. Herein, we developed a signature peptide-based technique for sensitively quantifying dissimilatory and assimilatory enzymes using nitrate-reducing enzymes in a hyporheic zone sediment as an example. Moreover, the measured changes in enzyme concentration were found to correlate with the nitrate reduction rate in a way different from that inferred from biogeochemical models based on biomass or functional genes as surrogates for functional enzymes. This phenomenon has important implications for understanding and modeling the dynamics of microbial community functions and biogeochemical processes in environments. Our results also demonstrate the importance of enzyme quantification for the identification and interrogation of those biogeochemical processes with low metabolite concentrations as a result of faster enzyme-catalyzed consumption of metabolites than their production. The dynamic enzyme behaviors provide a basis for the development of enzyme-based models to describe the relationship between the microbial community and biogeochemical processes.

  5. Combined effects of hydrologic alteration and cyprinid fish in mediating biogeochemical processes in a Mediterranean stream.

    Science.gov (United States)

    Rubio-Gracia, Francesc; Almeida, David; Bonet, Berta; Casals, Frederic; Espinosa, Carmen; Flecker, Alexander S; García-Berthou, Emili; Martí, Eugènia; Tuulaikhuu, Baigal-Amar; Vila-Gispert, Anna; Zamora, Lluis; Guasch, Helena

    2017-12-01

    Flow regimes are important drivers of both stream community and biogeochemical processes. However, the interplay between community and biogeochemical responses under different flow regimes in streams is less understood. In this study, we investigated the structural and functional responses of periphyton and macroinvertebrates to different densities of the Mediterranean barbel (Barbus meridionalis, Cyprinidae) in two stream reaches differing in flow regime. The study was conducted in Llémena Stream, a small calcareous Mediterranean stream with high nutrient levels. We selected a reach with permanent flow (permanent reach) and another subjected to flow regulation (regulated reach) with periods of flow intermittency. At each reach, we used in situ cages to generate 3 levels of fish density. Cages with 10 barbels were used to simulate high fish density (>7indm -2 ); cages with open sides were used as controls (i.e. exposed to actual fish densities of each stream reach) thus having low fish density; and those with no fish were used to simulate the disappearance of fish that occurs with stream drying. Differences in fish density did not cause significant changes in periphyton biomass and macroinvertebrate density. However, phosphate uptake by periphyton was enhanced in treatments lacking fish in the regulated reach with intermittent flow but not in the permanent reach, suggesting that hydrologic alteration hampers the ability of biotic communities to compensate for the absence of fish. This study indicates that fish density can mediate the effects of anthropogenic alterations such as flow intermittence derived from hydrologic regulation on stream benthic communities and associated biogeochemical processes, at least in eutrophic streams. Copyright © 2017. Published by Elsevier B.V.

  6. Seasonal Dynamics of Biogeochemical Processes in the Water Column of the Northeastern Black Sea

    Science.gov (United States)

    Rusanov, I. I.; Lein, A. Yu.; Makkaveev, P. N.; Klyuvitkin, A. A.; Kravchishina, M. D.; Ivanov, M. V.; Flint, M. V.

    2018-01-01

    Integrated studies on the hydrochemistry and water column rates of microbial processes in the eastern sector of the Black Sea along a standard 100-miles transect off Gelendzhik from the coast to the central part of the sea at water depths of 100-2170 m show that a series of warm winters and the absence of intense convective winter mixing resulted in a relatively low content of suspended particulate matter (SPM), particulate organic carbon (POC), and nutrients in the water column in March 2009. The relatively high SPM concentrations and the presence of isotopically light POC at the offshore station are indicative of the supply of terrigenous material from land and low contributions of phytoplanktonic organic matter to the composition of SPM. This may explain the low rates of biogeochemical processes in the water column near the coast. The surface layer at deep-water stations is dominated by isotopically heavy phytoplanktonic organic matter. This suggests that the supply of terrigenous material from land was insufficient in offshore deep-water areas. Therefore, warm winters and insufficient nutrient supply do not prevent photosynthesis in the photic layer of the deep-water zone, which generates organic substrates for heterotrophic aquatic communities. The results of isotopic analysis of POC, measurements of the rates biogeochemical processes, and the hydrochemical characteristics of the water column can be used to determine the nature and seasonal variability of the POC composition.

  7. Thermodynamics at work - on the limits and potentials of biogeochemical processes

    Science.gov (United States)

    Peiffer, Stefan

    2017-04-01

    on the Fe and S side (Peiffer & Wan, 2016; Wan et al, 2014) which will allow for the occurrence of cryptic sulphur cycles, i. e. high turnover of sulphide and sulfate without the appearance of dissolved sulphide species. References Beer, J; Blodau, C (2007): Transport and thermodynamics constrain belowground carbon turover in a northern peatland, Geochim. Cosmochim. Acta, 71, 2989-3002 Blodau, C. (2002). "Carbon cycling in peatlands: A review of processes and controls." Environmental Reviews 10(2): 111-134. Blodau, C; Hoffmann, S; Peine, A; Peiffer, S (1998): Iron and sulfate reduction in the sediments of acid mine lake 116 (Brandenburg, Germany): Rates and geochemical evaluation, Water, Air and Soil Pollution, 108, 249-270 Peiffer, S., Wan M. (2016) Reductive Dissolution and Reactivity of Ferric (Hydr)oxides, in Faivre, D., Iron Oxides: From Nature to Applications, Wiley-VCH, chapter 3, 29-51 Peine, A; Küsel, K; Tritschler, A; Peiffer, S (2000): Electron flow in an iron-rich acidic sedimant - evidence for an acidity-driven iron cycle, Limnol. Oceanogr., 45(5), 1077-1087 Stumm, W.; Morgan, J. J. (1996): Aquatic Chemistry, Wiley Wan, M., Shchukarev, A., Lohmayer, R., Planer-Friedrich, B., Peiffer, S. (2014) Occurrence of surface polysulfides during the interaction between ferric (hydr)oxides and aqueous sulfide. Environmental Science and Technology, 48, 5076-5084

  8. Particle methods for simulation of subsurface multiphase fluid flow and biogeochemical processes

    International Nuclear Information System (INIS)

    Meakin, Paul; Tartakovsky, Alexandre; Scheibe, Tim; Tartakovsky, Daniel; Redden, George; Long, Philip E; Brooks, Scott C; Xu Zhijie

    2007-01-01

    A number of particle models that are suitable for simulating multiphase fluid flow and biogeochemical processes have been developed during the last few decades. Here we discuss three of them: a microscopic model - molecular dynamics; a mesoscopic model - dissipative particle dynamics; and a macroscopic model - smoothed particle hydrodynamics. Particle methods are robust and versatile, and it is relatively easy to add additional physical, chemical and biological processes into particle codes. However, the computational efficiency of particle methods is low relative to continuum methods. Multiscale particle methods and hybrid (particle-particle and particle-continuum) methods are needed to improve computational efficiency and make effective use of emerging computational capabilities. These new methods are under development

  9. Biogeochemical Hotspots: Role of Small Wetlands in Nutrient Processing at the Watershed Scale

    Science.gov (United States)

    Cheng, F. Y.; Basu, N. B.

    2016-12-01

    Increased loading of nutrients (nitrogen N and phosphorus P) from agricultural and urban intensification in the Anthropocene has led to severe degradation of inland and coastal waters. Amongst aquatic ecosystems, wetlands receive and retain significant quantities of nutrients and thus are important regulators of nutrient transport in watersheds. While the factors controlling N and P retention in wetlands is relatively well known, there is a lack of quantitative understanding on the relative contributions of the different factors on nutrient retention. There is also a deficiency in knowledge of how these processes behave across system size and type. In our study, we synthesized nutrient retention data from wetlands, lakes, and reservoirs to gain insight on the relationship between hydrologic and biogeochemical controls on nutrient retention. Our results indicated that the first-order reaction rate constant, k [T-1], is inversely proportional to the hydraulic residence time, τ, across six orders of magnitude in residence time for total nitrogen, total phosphorus, nitrate and phosphate. We hypothesized that the consistency of the relationship across constituent and system types points to the strong hydrologic control on biogeochemical processing. The hypothesis was tested using a two-compartment mechanistic model that links the nutrient removal processes (denitrification for N and sedimentation for P) with the system size. Finally, the k-τ relationships were upscaled with a regional size-frequency distribution to demonstrate the disproportionately large role of small wetlands in watershed-scale nutrient processing. Our results highlight the importance of hydrological controls as the dominant modifiers of nutrient removal mechanisms and the need for a stronger focus on small lentic ecosystems like wetlands as major nutrient sinks in the landscape.

  10. Links between contaminant hotspots in low flow estuarine systems and altered sediment biogeochemical processes

    Science.gov (United States)

    Sutherland, Michael D.; Dafforn, Katherine A.; Scanes, Peter; Potts, Jaimie; Simpson, Stuart L.; Sim, Vivian X. Y.; Johnston, Emma L.

    2017-11-01

    The urbanisation of coastal zones is a major threat to the health of global estuaries and has been linked to increased contamination (e.g. metals) and excess organic matter. Urban stormwater networks collect and funnel contaminants into waterways at point sources (e.g. stormdrains). Under dry, low flow conditions, these stormwater contaminants can accumulate in sediments over time and result in modifications to benthic sediment biogeochemical processes. To quantify these processes, this field study measured differences in benthic metabolism (CR, GPP, NEM) and sediment-water nutrient fluxes (NH3, NOx, PO4) associated with stormdrains (0 m, 200 m and 1000 m away) and increased water-retention (embayments vs channels). Significant changes to benthic metabolism were detected with distance from stormdrains, and with differences in water-retention rates, above natural spatial and temporal variation. Oxygen consumption was ∼50% higher at stormdrains (0 m) compared to 1000 m away and >70% higher at stormdrains (0 m) located in embayments compared to channels. Oxygen production also appeared to decrease with distance from stormdrains in embayments, but patterns were variable. These changes to benthic metabolism were of a magnitude expected to influence benthic nutrient cycling, but NH3, NOx and PO4 fluxes were generally low, and highly spatially and temporally variable. Overall, metal (Cu) contamination explained most of the variation in sediment biogeochemical processes between embayments and channels, while sediment grain size explained differences in fluxes with distance from stormdrains. Importantly, although there was evidence of increased productivity associated with stormdrains, we also detected evidence of early hypoxia suggesting that systems with legacy stormwater contaminants exist on a tipping point. Future work should investigate changes to sediment processes after a major rainfall event, when large and sudden inputs of potentially toxic contaminants occur

  11. Chesapeake Bay nitrogen fluxes derived from a land‐estuarine ocean biogeochemical modeling system: Model description, evaluation, and nitrogen budgets

    Science.gov (United States)

    Friedrichs, Marjorie A. M.; Wilkin, John; Tian, Hanqin; Yang, Qichun; Hofmann, Eileen E.; Wiggert, Jerry D.; Hood, Raleigh R.

    2015-01-01

    Abstract The Chesapeake Bay plays an important role in transforming riverine nutrients before they are exported to the adjacent continental shelf. Although the mean nitrogen budget of the Chesapeake Bay has been previously estimated from observations, uncertainties associated with interannually varying hydrological conditions remain. In this study, a land‐estuarine‐ocean biogeochemical modeling system is developed to quantify Chesapeake riverine nitrogen inputs, within‐estuary nitrogen transformation processes and the ultimate export of nitrogen to the coastal ocean. Model skill was evaluated using extensive in situ and satellite‐derived data, and a simulation using environmental conditions for 2001–2005 was conducted to quantify the Chesapeake Bay nitrogen budget. The 5 year simulation was characterized by large riverine inputs of nitrogen (154 × 109 g N yr−1) split roughly 60:40 between inorganic:organic components. Much of this was denitrified (34 × 109 g N yr−1) and buried (46 × 109 g N yr−1) within the estuarine system. A positive net annual ecosystem production for the bay further contributed to a large advective export of organic nitrogen to the shelf (91 × 109 g N yr−1) and negligible inorganic nitrogen export. Interannual variability was strong, particularly for the riverine nitrogen fluxes. In years with higher than average riverine nitrogen inputs, most of this excess nitrogen (50–60%) was exported from the bay as organic nitrogen, with the remaining split between burial, denitrification, and inorganic export to the coastal ocean. In comparison to previous simulations using generic shelf biogeochemical model formulations inside the estuary, the estuarine biogeochemical model described here produced more realistic and significantly greater exports of organic nitrogen and lower exports of inorganic nitrogen to the shelf. PMID:27668137

  12. Chesapeake Bay nitrogen fluxes derived from a land-estuarine ocean biogeochemical modeling system: Model description, evaluation, and nitrogen budgets.

    Science.gov (United States)

    Feng, Yang; Friedrichs, Marjorie A M; Wilkin, John; Tian, Hanqin; Yang, Qichun; Hofmann, Eileen E; Wiggert, Jerry D; Hood, Raleigh R

    2015-08-01

    The Chesapeake Bay plays an important role in transforming riverine nutrients before they are exported to the adjacent continental shelf. Although the mean nitrogen budget of the Chesapeake Bay has been previously estimated from observations, uncertainties associated with interannually varying hydrological conditions remain. In this study, a land-estuarine-ocean biogeochemical modeling system is developed to quantify Chesapeake riverine nitrogen inputs, within-estuary nitrogen transformation processes and the ultimate export of nitrogen to the coastal ocean. Model skill was evaluated using extensive in situ and satellite-derived data, and a simulation using environmental conditions for 2001-2005 was conducted to quantify the Chesapeake Bay nitrogen budget. The 5 year simulation was characterized by large riverine inputs of nitrogen (154 × 10 9  g N yr -1 ) split roughly 60:40 between inorganic:organic components. Much of this was denitrified (34 × 10 9  g N yr -1 ) and buried (46 × 10 9  g N yr -1 ) within the estuarine system. A positive net annual ecosystem production for the bay further contributed to a large advective export of organic nitrogen to the shelf (91 × 10 9  g N yr -1 ) and negligible inorganic nitrogen export. Interannual variability was strong, particularly for the riverine nitrogen fluxes. In years with higher than average riverine nitrogen inputs, most of this excess nitrogen (50-60%) was exported from the bay as organic nitrogen, with the remaining split between burial, denitrification, and inorganic export to the coastal ocean. In comparison to previous simulations using generic shelf biogeochemical model formulations inside the estuary, the estuarine biogeochemical model described here produced more realistic and significantly greater exports of organic nitrogen and lower exports of inorganic nitrogen to the shelf.

  13. Saltwater intrusion into tidal freshwater marshes alters the biogeochemical processing of organic carbon

    Science.gov (United States)

    Neubauer, S. C.; Franklin, R. B.; Berrier, D. J.

    2013-12-01

    Environmental perturbations in wetlands affect the integrated plant-microbial-soil system, causing biogeochemical responses that can manifest at local to global scales. The objective of this study was to determine how saltwater intrusion affects carbon mineralization and greenhouse gas production in coastal wetlands. Working with tidal freshwater marsh soils that had experienced ~ 3.5 yr of in situ saltwater additions, we quantified changes in soil properties, measured extracellular enzyme activity associated with organic matter breakdown, and determined potential rates of anaerobic carbon dioxide (CO2) and methane (CH4) production. Soils from the field plots treated with brackish water had lower carbon content and higher C : N ratios than soils from freshwater plots, indicating that saltwater intrusion reduced carbon availability and increased organic matter recalcitrance. This was reflected in reduced activities of enzymes associated with the hydrolysis of cellulose and the oxidation of lignin, leading to reduced rates of soil CO2 and CH4 production. The effects of long-term saltwater additions contrasted with the effects of short-term exposure to brackish water during three-day laboratory incubations, which increased rates of CO2 production but lowered rates of CH4 production. Collectively, our data suggest that the long-term effect of saltwater intrusion on soil CO2 production is indirect, mediated through the effects of elevated salinity on the quantity and quality of autochthonous organic matter inputs to the soil. In contrast, salinity, organic matter content, and enzyme activities directly influence CH4 production. Our analyses demonstrate that saltwater intrusion into tidal freshwater marshes affects the entire process of carbon mineralization, from the availability of organic carbon through its terminal metabolism to CO2 and/or CH4, and illustrate that long-term shifts in biogeochemical functioning are not necessarily consistent with short

  14. Silicon cycle in Indian estuaries and its control by biogeochemical and anthropogenic processes

    Science.gov (United States)

    Mangalaa, K. R.; Cardinal, D.; Brajard, J.; Rao, D. B.; Sarma, N. S.; Djouraev, I.; Chiranjeevulu, G.; Murty, K. Narasimha; Sarma, V. V. S. S.

    2017-09-01

    We study the silicon biogeochemical cycle and its associated parameters in 24 and 18 Indian estuaries during dry and wet periods respectively. We focus more specifically on dissolved Si (DSi), amorphous Si (ASi,) lithogenic Si (LSi), Particulate Organic Carbon (POC), Total Suspended Material (TSM), Dissolved Inorganic Nitrogen (DIN), salinity and fucoxanthin, a marker pigment for diatoms. Overall, we show that the estuaries have strong inter and intra variability of their biogeochemical parameters both seasonally and along salinity gradients. Based on Principal Component Analysis and clustering of categorised (upper and lower) estuaries, we discuss the four major processes controlling the Si variability of Indian estuaries: 1) lithogenic supply, 2) diatom uptake, 3) mixing of sea water and, 4) land use. The influence of lithogenic control is significantly higher during the wet period than during the dry period, due to a higher particle supply through monsoonal discharge. A significant diatom uptake is only identified in the estuaries during dry period. By taking into account the non-conservative nature of Si and by extrapolating our results, we estimate the fluxes from the Indian subcontinent of DSi, ASi, LSi to the Bay of Bengal (211 ± 32, 10 ± 4.7, 2028 ± 317 Gmol) and Arabian Sea (80 ± 15, 7 ± 1.1, 1717 ± 932 Gmol). We show the impact of land use in watersheds with higher levels of agricultural activity amplifies the supply of Si to the coastal Bay of Bengal during the wet season. In contrast, forest cover and steep slopes cause less Si supply to the Arabian Sea by restricting erosion when entering the estuary. Finally, Si:N ratios show that nitrogen is always in deficit relative to silicon for diatom growth, these high Si:N ratios likely contribute to the prevention of eutrophication in the Indian estuaries and coastal sea.

  15. The UK Earth System Models Marine Biogeochemical Evaluation Toolkit, BGC-val

    Science.gov (United States)

    de Mora, Lee

    2017-04-01

    The Biogeochemical Validation toolkit, BGC-val, is a model and grid independent python-based marine model evaluation framework that automates much of the validation of the marine component of an Earth System Model. BGC-val was initially developed to be a flexible and extensible system to evaluate the spin up of the marine UK Earth System Model (UKESM). However, the grid-independence and flexibility means that it is straightforward to adapt the BGC-val framework to evaluate other marine models. In addition to the marine component of the UKESM, this toolkit has been adapted to compare multiple models, including models from the CMIP5 and iMarNet inter-comparison projects. The BGC-val toolkit produces multiple levels of analysis which are presented in a simple to use interactive html5 document. Level 1 contains time series analyses, showing the development over time of many important biogeochemical and physical ocean metrics, such as the Global primary production or the Drake passage current. The second level of BGC-val is an in-depth spatial analyses of a single point in time. This is a series of point to point comparison of model and data in various regions, such as a comparison of Surface Nitrate in the model vs data from the world ocean atlas. The third level analyses are specialised ad-hoc packages to go in-depth on a specific question, such as the development of Oxygen minimum zones in the Equatorial Pacific. In additional to the three levels, the html5 document opens with a Level 0 table showing a summary of the status of the model run. The beta version of this toolkit is available via the Plymouth Marine Laboratory Gitlab server and uses the BSD 3 clause license.

  16. The effect of tidal forcing on biogeochemical processes in intertidal salt marsh sediments

    Directory of Open Access Journals (Sweden)

    Neuhuber Stephanie

    2007-06-01

    Full Text Available Abstract Background Early diagenetic processes involved in natural organic matter (NOM oxidation in marine sediments have been for the most part characterized after collecting sediment cores and extracting porewaters. These techniques have proven useful for deep-sea sediments where biogeochemical processes are limited to aerobic respiration, denitrification, and manganese reduction and span over several centimeters. In coastal marine sediments, however, the concentration of NOM is so high that the spatial resolution needed to characterize these processes cannot be achieved with conventional sampling techniques. In addition, coastal sediments are influenced by tidal forcing that likely affects the processes involved in carbon oxidation. Results In this study, we used in situ voltammetry to determine the role of tidal forcing on early diagenetic processes in intertidal salt marsh sediments. We compare ex situ measurements collected seasonally, in situ profiling measurements, and in situ time series collected at several depths in the sediment during tidal cycles at two distinct stations, a small perennial creek and a mud flat. Our results indicate that the tides coupled to the salt marsh topography drastically influence the distribution of redox geochemical species and may be responsible for local differences noted year-round in the same sediments. Monitoring wells deployed to observe the effects of the tides on the vertical component of porewater transport reveal that creek sediments, because of their confinements, are exposed to much higher hydrostatic pressure gradients than mud flats. Conclusion Our study indicates that iron reduction can be sustained in intertidal creek sediments by a combination of physical forcing and chemical oxidation, while intertidal mud flat sediments are mainly subject to sulfate reduction. These processes likely allow microbial iron reduction to be an important terminal electron accepting process in intertidal coastal

  17. Molecular organic tracers of biogeochemical processes in a saline meromictic lake (Ace Lake)

    NARCIS (Netherlands)

    Sinninghe Damsté, J.S.; Schouten, S.; Rijpstra, W.I.C.; Kok, M.D.; Hopmans, E.C.; Summons, R.E.; Volkman, J.K.

    2001-01-01

    The chemical structures, distribution and stable carbon isotopic compositions of lipids in a sediment core taken in meromictic Ace Lake (Antarctica) were analyzed to trace past biogeochemical cycling. Biomarkers from methanogenic archaea, methanotrophic bacteria and photosynthetic green sulfur

  18. Caught in the flux net: disentangling error, uncertainty, heterogeneity, and spatial process in biogeochemical scaling

    Science.gov (United States)

    Dietze, M.

    2014-12-01

    Attempts to link observations across multiple scales, and in particular the problem of scaling up fine-scale observations to landscape and regional process, faces numerous theoretical, computational, and statistical challenges. This talk aims to link theoretical advances in the scaling of biotic heterogeneity, abiotic heterogeneity, and contagious disturbance with statistical advances for linking observations that integrate over different scales. Critical to this goal is the need to partition sources of uncertainty and variability. In particular, the variance you can calculate most readily is rarely the most important or relevant one to quantify. In community ecology, hierarchical Bayes (HB) latent-variable models that separate true variability in ecosystem processes from observation errors have challenged long-standing theory surrounding the maintenance of biodiversity, yet application of such approaches to regional-scale biogeochemical processes is just beginning. A special case of such models, focused on the change of support problem, deal specifically with linking observations that integrate over different spatial and temporal scales. Occurring in parallel with these statistical advances have been the development of new theories for the spatially-implicit scaling of biotic and abiotic heterogeneity, as well as contagious disturbances such as fire and pathogens, and the incorporation of such approaches into process-based ecosystem models. Such approaches upscale by integrating the probability distributions of system heterogeneity over the functional response of the ecosystem to such heterogeneity. We demonstrate that this approach can also be downscaled by conditioning on incomplete partial observation at a local scale, and can have lower uncertainty than brute-force spatially-explicit approaches. We also extend such approaches from integrating over observed heterogeneities to integrating the latent, high-dimensional variability in HB models. Finally, there is a

  19. Relating hyporheic fluxes, residence times, and redox-sensitive biogeochemical processes upstream of beaver dams

    Science.gov (United States)

    Briggs, Martin A.; Lautz, Laura; Hare, Danielle K.

    2013-01-01

    Abstract. Small dams enhance the development of patchy microenvironments along stream corridors by trapping sediment and creating complex streambed morphologies. This patchiness drives intricate hyporheic flux patterns that govern the exchange of O2 and redox-sensitive solutes between the water column and the stream bed. We used multiple tracer techniques, naturally occurring and injected, to evaluate hyporheic flow dynamics and associated biogeochemical cycling and microbial reactivity around 2 beaver dams in Wyoming (USA). High-resolution fiber-optic distributed temperature sensing was used to collect temperature data over 9 vertical streambed profiles and to generate comprehensive vertical flux maps using 1-dimensional (1-D) heat-transport modeling. Coincident with these locations, vertical profiles of hyporheic water were collected every week and analyzed for dissolved O2, pH, dissolved organic C, and several conservative and redox-sensitive solutes. In addition, hyporheic and net stream aerobic microbial reactivity were analyzed with a constant-rate injection of the biologically sensitive resazurin (Raz) smart tracer. The combined results revealed a heterogeneous system with rates of downwelling hyporheic flow organized by morphologic unit and tightly coupled to the redox conditions of the subsurface. Principal component analysis was used to summarize the variability of all redox-sensitive species, and results indicated that hyporheic water varied from oxic-stream-like to anoxic-reduced in direct response to the hydrodynamic conditions and associated residence times. The anaerobic transition threshold predicted by the mean O2 Damko

  20. Seasonal Variation in Floodplain Biogeochemical Processing in a Restored Headwater Stream.

    Science.gov (United States)

    Jones, C Nathan; Scott, Durelle T; Guth, Christopher; Hester, Erich T; Hession, W Cully

    2015-11-17

    Stream and river restoration activities have recently begun to emphasize the enhancement of biogeochemical processing within river networks through the restoration of river-floodplain connectivity. It is generally accepted that this practice removes pollutants such as nitrogen and phosphorus because the increased contact time of nutrient-rich floodwaters with reactive floodplain sediments. Our study examines this assumption in the floodplain of a recently restored, low-order stream through five seasonal experiments. During each experiment, a floodplain slough was artificially inundated for 3 h. Both the net flux of dissolved nutrients and nitrogen uptake rate were measured during each experiment. The slough was typically a source of dissolved phosphorus and dissolved organic matter, a sink of NO3(-), and variable source/sink of ammonium. NO3(-) uptake rates were relatively high when compared to riverine uptake, especially during the spring and summer experiments. However, when scaled up to the entire 1 km restoration reach with a simple inundation model, less than 0.5-1.5% of the annual NO3(-) load would be removed because of the short duration of river-floodplain connectivity. These results suggest that restoring river-floodplain connectivity is not necessarily an appropriate best management practice for nutrient removal in low-order streams with legacy soil nutrients from past agricultural landuse.

  1. Preliminary results on the influence of river discharges on biogeochemical processes in Godavari estuary and Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    DileepKumar, M.

    ) flushing of the estuary, (b) temporal variability in mixing processes, (c) discharge of nutrients, (d) evolution of biological productivity patterns, and (e) associated biogeochemical processes in mind, we have planned and carrying out systematic studies... the sampling. Vertical profiles of temperature and salinity were obtained using a portable Sea Bird CTD system. Oxygen was estimated by Winkler's titration and nutrients (nitrite, nitrate, ammonia, phosphate and silicate) were analyzed spectrophotometrically...

  2. Anthropogenic forcing of estuarine hypoxic events in sub-tropical catchments: landscape drivers and biogeochemical processes.

    Science.gov (United States)

    Wong, Vanessa N L; Johnston, Scott G; Burton, Edward D; Bush, Richard T; Sullivan, Leigh A; Slavich, Peter G

    2011-11-15

    Episodic hypoxic events can occur following summer floods in sub-tropical estuaries of eastern Australia. These events can cause deoxygenation of waterways and extensive fish mortality. Here, we present a conceptual model that links key landscape drivers and biogeochemical processes which contribute to post-flood hypoxic events. The model provides a framework for examining the nature of anthropogenic forcing. Modification of estuarine floodplain surface hydrology through the construction of extensive drainage networks emerges as a major contributing factor to increasing the frequency, magnitude and duration of hypoxic events. Forcing occurs in two main ways. Firstly, artificial drainage of backswamp wetlands initiates drier conditions which cause a shift in vegetation assemblages from wetland-dominant species to dryland-dominant species. These species, which currently dominate the floodplain, are largely intolerant of inundation and provide abundant labile substrate for decomposition following flood events. Decomposition of this labile carbon pool consumes oxygen in the overlying floodwaters, and results in anoxic conditions and waters with excess deoxygenation potential (DOP). Carbon metabolism can be strongly coupled with microbially-mediated reduction of accumulated Fe and Mn oxides, phases which are common on these coastal floodplain landscapes. Secondly, artificial drainage enhances discharge rates during the flood recession phase. Drains transport deoxygenated high DOP floodwaters rapidly from backswamp wetlands to the main river channel to further consume oxygen. This process effectively displaces the natural carbon metabolism processes from floodplain wetlands to the main channel. Management options to reduce the impacts of post-flood hypoxia include i) remodifying drainage on the floodplain to promote wetter conditions, thereby shifting vegetation assemblages towards inundation-tolerant species, and ii) strategic retention of floodwaters in the backswamp

  3. Biogeochemical processes and buffering capacity concurrently affect acidification in a seasonally hypoxic coastal marine basin

    Science.gov (United States)

    Hagens, M.; Slomp, C. P.; Meysman, F. J. R.; Seitaj, D.; Harlay, J.; Borges, A. V.; Middelburg, J. J.

    2015-03-01

    Coastal areas are impacted by multiple natural and anthropogenic processes and experience stronger pH fluctuations than the open ocean. These variations can weaken or intensify the ocean acidification signal induced by increasing atmospheric pCO2. The development of eutrophication-induced hypoxia intensifies coastal acidification, since the CO2 produced during respiration decreases the buffering capacity in any hypoxic bottom water. To assess the combined ecosystem impacts of acidification and hypoxia, we quantified the seasonal variation in pH and oxygen dynamics in the water column of a seasonally stratified coastal basin (Lake Grevelingen, the Netherlands). Monthly water-column chemistry measurements were complemented with estimates of primary production and respiration using O2 light-dark incubations, in addition to sediment-water fluxes of dissolved inorganic carbon (DIC) and total alkalinity (TA). The resulting data set was used to set up a proton budget on a seasonal scale. Temperature-induced seasonal stratification combined with a high community respiration was responsible for the depletion of oxygen in the bottom water in summer. The surface water showed strong seasonal variation in process rates (primary production, CO2 air-sea exchange), but relatively small seasonal pH fluctuations (0.46 units on the total hydrogen ion scale). In contrast, the bottom water showed less seasonality in biogeochemical rates (respiration, sediment-water exchange), but stronger pH fluctuations (0.60 units). This marked difference in pH dynamics could be attributed to a substantial reduction in the acid-base buffering capacity of the hypoxic bottom water in the summer period. Our results highlight the importance of acid-base buffering in the pH dynamics of coastal systems and illustrate the increasing vulnerability of hypoxic, CO2-rich waters to any acidifying process.

  4. Understanding system disturbance and ecosystem services in restored saltmarshes: Integrating physical and biogeochemical processes

    Science.gov (United States)

    Spencer, K. L.; Harvey, G. L.

    2012-06-01

    Coastal saltmarsh ecosystems occupy only a small percentage of Earth's land surface, yet contribute a wide range of ecosystem services that have significant global economic and societal value. These environments currently face significant challenges associated with climate change, sea level rise, development and water quality deterioration and are consequently the focus of a range of management schemes. Increasingly, soft engineering techniques such as managed realignment (MR) are being employed to restore and recreate these environments, driven primarily by the need for habitat (re)creation and sustainable coastal flood defence. Such restoration schemes also have the potential to provide additional ecosystem services including climate regulation and waste processing. However, these sites have frequently been physically impacted by their previous land use and there is a lack of understanding of how this 'disturbance' impacts the delivery of ecosystem services or of the complex linkages between ecological, physical and biogeochemical processes in restored systems. Through the exploration of current data this paper determines that hydrological, geomorphological and hydrodynamic functioning of restored sites may be significantly impaired with respects to natural 'undisturbed' systems and that links between morphology, sediment structure, hydrology and solute transfer are poorly understood. This has consequences for the delivery of seeds, the provision of abiotic conditions suitable for plant growth, the development of microhabitats and the cycling of nutrients/contaminants and may impact the delivery of ecosystem services including biodiversity, climate regulation and waste processing. This calls for a change in our approach to research in these environments with a need for integrated, interdisciplinary studies over a range of spatial and temporal scales incorporating both intensive and extensive research design.

  5. Biogeochemical cycles of Chernobyl-born radionuclides in the contaminated forest ecosystems: long-term dynamics of the migration processes

    Science.gov (United States)

    Shcheglov, Alexey; Tsvetnova, Ol'ga; Klyashtorin, Alexey

    2013-04-01

    Biogeochemical migration is a dominant factor of the radionuclide transport through the biosphere. In the early XX century, V.I. Vernadskii, a Russian scientist known, noted about a special role living things play in transport and accumulation of natural radionuclide in various environments. The role of biogeochemical processes in migration and redistribution of technogenic radionuclides is not less important. In Russia, V. M. Klechkovskii and N.V. Timofeev-Ressovskii showed some important biogeochemical aspects of radionuclide migration by the example of global fallout and Kyshtym accident. Their followers, R.M. Alexakhin, M.A. Naryshkin, N.V. Kulikov, F.A. Tikhomirov, E.B. Tyuryukanova, and others also contributed a lot to biogeochemistry of radionuclides. In the post-Chernobyl period, this area of knowledge received a lot of data that allowed building the radioactive element balance and flux estimation in various biogeochemical cycles [Shcheglov et al., 1999]. Regrettably, many of recent radioecological studies are only focused on specific radionuclide fluxes or pursue some applied tasks, missing the holistic approach. Most of the studies consider biogeochemical fluxes of radioactive isotopes in terms of either dose estimation or radionuclide migration rates in various food chains. However, to get a comprehensive picture and develop a reliable forecast of environmental, ecological, and social consequences of radioactive pollution in a vast contaminated area, it is necessary to investigate all the radionuclide fluxes associated with the biogeochemical cycles in affected ecosystems. We believe such an integrated approach would be useful to study long-term environmental consequences of the Fukushima accident as well. In our long-term research, we tried to characterize the flux dynamics of the Chernobyl-born radionuclides in the contaminated forest ecosystems and landscapes as a part of the integrated biogeochemical process. Our field studies were started in June of

  6. Monitoring Biogeochemical Processes in Coral Reef Environments with Remote Sensing: A Cross-Disciplinary Approach.

    Science.gov (United States)

    Perez, D.; Phinn, S. R.; Roelfsema, C. M.; Shaw, E. C.; Johnston, L.; Iguel, J.; Camacho, R.

    2017-12-01

    Primary production and calcification are important to measure and monitor over time, because of their fundamental roles in the carbon cycling and accretion of habitat structure for reef ecosystems. However, monitoring biogeochemical processes in coastal environments has been difficult due to complications in resolving differences in water optical properties from biological productivity and other sources (sediment, dissolved organics, etc.). This complicates application of algorithms developed for satellite image data from open ocean conditions, and requires alternative approaches. This project applied a cross-disciplinary approach, using established methods for monitoring productivity in terrestrial environments to coral reef systems. Availability of regularly acquired high spatial (reefs. There is potential to further develop optical models for remote sensing applications to estimate and monitor reef system processes, such as primary productivity and calcification. This project collected field measurements of spectral absorptance and primary productivity and calcification rates for two reef systems: Heron Reef, southern Great Barrier Reef and Saipan Lagoon, Commonwealth of the Northern Mariana Islands. Field data were used to parameterize a light-use efficiency (LUE) model, estimating productivity from absorbed photosynthetically active radiation. The LUE model has been successfully applied in terrestrial environments for the past 40 years, and could potentially be used in shallow, marine environments. The model was used in combination with a map of benthic community composition produced from objective based image analysis of WorldView 2 imagery. Light-use efficiency was measured for functional groups: coral, algae, seagrass, and sediment. However, LUE was overestimated for sediment, which led to overestimation of productivity for the mapped area. This was due to differences in spatial and temporal resolution of field data used in the model. The limitations and

  7. Evaluation of the transport matrix method for simulation of ocean biogeochemical tracers

    Science.gov (United States)

    Kvale, Karin F.; Khatiwala, Samar; Dietze, Heiner; Kriest, Iris; Oschlies, Andreas

    2017-06-01

    Conventional integration of Earth system and ocean models can accrue considerable computational expenses, particularly for marine biogeochemical applications. Offline numerical schemes in which only the biogeochemical tracers are time stepped and transported using a pre-computed circulation field can substantially reduce the burden and are thus an attractive alternative. One such scheme is the transport matrix method (TMM), which represents tracer transport as a sequence of sparse matrix-vector products that can be performed efficiently on distributed-memory computers. While the TMM has been used for a variety of geochemical and biogeochemical studies, to date the resulting solutions have not been comprehensively assessed against their online counterparts. Here, we present a detailed comparison of the two. It is based on simulations of the state-of-the-art biogeochemical sub-model embedded within the widely used coarse-resolution University of Victoria Earth System Climate Model (UVic ESCM). The default, non-linear advection scheme was first replaced with a linear, third-order upwind-biased advection scheme to satisfy the linearity requirement of the TMM. Transport matrices were extracted from an equilibrium run of the physical model and subsequently used to integrate the biogeochemical model offline to equilibrium. The identical biogeochemical model was also run online. Our simulations show that offline integration introduces some bias to biogeochemical quantities through the omission of the polar filtering used in UVic ESCM and in the offline application of time-dependent forcing fields, with high latitudes showing the largest differences with respect to the online model. Differences in other regions and in the seasonality of nutrients and phytoplankton distributions are found to be relatively minor, giving confidence that the TMM is a reliable tool for offline integration of complex biogeochemical models. Moreover, while UVic ESCM is a serial code, the TMM can

  8. Evaluation of the transport matrix method for simulation of ocean biogeochemical tracers

    Directory of Open Access Journals (Sweden)

    K. F. Kvale

    2017-06-01

    Full Text Available Conventional integration of Earth system and ocean models can accrue considerable computational expenses, particularly for marine biogeochemical applications. Offline numerical schemes in which only the biogeochemical tracers are time stepped and transported using a pre-computed circulation field can substantially reduce the burden and are thus an attractive alternative. One such scheme is the transport matrix method (TMM, which represents tracer transport as a sequence of sparse matrix–vector products that can be performed efficiently on distributed-memory computers. While the TMM has been used for a variety of geochemical and biogeochemical studies, to date the resulting solutions have not been comprehensively assessed against their online counterparts. Here, we present a detailed comparison of the two. It is based on simulations of the state-of-the-art biogeochemical sub-model embedded within the widely used coarse-resolution University of Victoria Earth System Climate Model (UVic ESCM. The default, non-linear advection scheme was first replaced with a linear, third-order upwind-biased advection scheme to satisfy the linearity requirement of the TMM. Transport matrices were extracted from an equilibrium run of the physical model and subsequently used to integrate the biogeochemical model offline to equilibrium. The identical biogeochemical model was also run online. Our simulations show that offline integration introduces some bias to biogeochemical quantities through the omission of the polar filtering used in UVic ESCM and in the offline application of time-dependent forcing fields, with high latitudes showing the largest differences with respect to the online model. Differences in other regions and in the seasonality of nutrients and phytoplankton distributions are found to be relatively minor, giving confidence that the TMM is a reliable tool for offline integration of complex biogeochemical models. Moreover, while UVic ESCM is a serial

  9. Physical Controls on Biogeochemical Processes in Intertidal Zones of Beach Aquifers

    Science.gov (United States)

    Heiss, James W.; Post, Vincent E. A.; Laattoe, Tariq; Russoniello, Christopher J.; Michael, Holly A.

    2017-11-01

    Marine ecosystems are sensitive to inputs of chemicals from submarine groundwater discharge. Tidally influenced saltwater-freshwater mixing zones in beach aquifers can host biogeochemical transformations that modify chemical loads prior to discharge. A numerical variable-density groundwater flow and reactive transport model was used to evaluate the physical controls on reactivity for mixing-dependent and mixing-independent reactions in beach aquifers, represented as denitrification and sulfate reduction, respectively. A sensitivity analysis was performed across typical values of tidal amplitude, hydraulic conductivity, terrestrial freshwater flux, beach slope, dispersivity, and DOC reactivity. For the model setup and conditions tested, the simulations demonstrate that denitrification can remove up to 100% of terrestrially derived nitrate, and sulfate reduction can transform up to 8% of seawater-derived sulfate prior to discharge. Tidally driven mixing between saltwater and freshwater promotes denitrification along the boundary of the intertidal saltwater circulation cell in pore water between 1 and 10 ppt. The denitrification zone occupies on average 49% of the mixing zone. Denitrification rates are highest on the landward side of the circulation cell and decrease along circulating flow paths. Reactivity for mixing-dependent reactions increases with the size of the mixing zone and solute supply, while mixing-independent reactivity is controlled primarily by solute supply. The results provide insights into the types of beaches most efficient in altering fluxes of chemicals prior to discharge and could be built upon to help engineer beaches to enhance reactivity. The findings have implications for management to protect coastal ecosystems and the estimation of chemical fluxes to the ocean.

  10. An integrated multi-level watershed-reservoir modeling system for examining hydrological and biogeochemical processes in small prairie watersheds.

    Science.gov (United States)

    Zhang, Hua; Huang, Guo H; Wang, Dunling; Zhang, Xiaodong; Li, Gongchen; An, Chunjiang; Cui, Zheng; Liao, Renfei; Nie, Xianghui

    2012-03-15

    Eutrophication of small prairie reservoirs presents a major challenge in water quality management and has led to a need for predictive water quality modeling. Studies are lacking in effectively integrating watershed models and reservoir models to explore nutrient dynamics and eutrophication pattern. A water quality model specific to small prairie water bodies is also desired in order to highlight key biogeochemical processes with an acceptable degree of parameterization. This study presents a Multi-level Watershed-Reservoir Modeling System (MWRMS) to simulate hydrological and biogeochemical processes in small prairie watersheds. It integrated a watershed model, a hydrodynamic model and an eutrophication model into a flexible modeling framework. It can comprehensively describe hydrological and biogeochemical processes across different spatial scales and effectively deal with the special drainage structure of small prairie watersheds. As a key component of MWRMS, a three-dimensional Willows Reservoir Eutrophication Model (WREM) is developed to addresses essential biogeochemical processes in prairie reservoirs and to generate 3D distributions of various water quality constituents; with a modest degree of parameterization, WREM is able to meet the limit of data availability that often confronts the modeling practices in small watersheds. MWRMS was applied to the Assiniboia Watershed in southern Saskatchewan, Canada. Extensive efforts of field work and lab analysis were undertaken to support model calibration and validation. MWRMS demonstrated its ability to reproduce the observed watershed water yield, reservoir water levels and temperatures, and concentrations of several water constituents. Results showed that the aquatic systems in the Assiniboia Watershed were nitrogen-limited and sediment flux played a crucial role in reservoir nutrient budget and dynamics. MWRMS can provide a broad context of decision support for water resources management and water quality

  11. Analyzing the ecosystem carbon and hydrologic characteristics of forested wetland using a biogeochemical process model

    Science.gov (United States)

    Jianbo Cui; Changsheng Li; Carl Trettin

    2005-01-01

    A comprehensive biogeochemical model, Wetland-DNDC, was applied to analyze the carbon and hydrologic characteristics of forested wetland ecosystem at Minnesota (MN) and Florida (FL) sites. The model simulates the flows of carbon, energy, and water in forested wetlands. Modeled carbon dynamics depends on physiological plant factors, the size of plant pools,...

  12. Identifying biogeochemical processes beneath stormwater infiltration ponds in support of a new best management practice for groundwater protection

    Science.gov (United States)

    O'Reilly, Andrew M.; Chang, Ni-Bin; Wanielista, Martin P.; Xuan, Zhemin; Schirmer, Mario; Hoehn, Eduard; Vogt, Tobias

    2011-01-01

     When applying a stormwater infiltration pond best management practice (BMP) for protecting the quality of underlying groundwater, a common constituent of concern is nitrate. Two stormwater infiltration ponds, the SO and HT ponds, in central Florida, USA, were monitored. A temporal succession of biogeochemical processes was identified beneath the SO pond, including oxygen reduction, denitrification, manganese and iron reduction, and methanogenesis. In contrast, aerobic conditions persisted beneath the HT pond, resulting in nitrate leaching into groundwater. Biogeochemical differences likely are related to soil textural and hydraulic properties that control surface/subsurface oxygen exchange. A new infiltration BMP was developed and a full-scale application was implemented for the HT pond. Preliminary results indicate reductions in nitrate concentration exceeding 50% in soil water and shallow groundwater beneath the HT pond.

  13. Saltwater intrusion into tidal freshwater marshes alters the biogeochemical processing of organic carbon

    OpenAIRE

    Neubauer, S. C.; Franklin, R. B.; Berrier, D. J.

    2013-01-01

    Environmental perturbations in wetlands affect the integrated plant-microbial-soil system, causing biogeochemical responses that can manifest at local to global scales. The objective of this study was to determine how saltwater intrusion affects carbon mineralization and greenhouse gas production in coastal wetlands. Working with tidal freshwater marsh soils that had experienced ~ 3.5 yr of in situ saltwater additions, we quantified changes in soil properties, measured ex...

  14. Saltwater intrusion into tidal freshwater marshes alters the biogeochemical processing of organic carbon

    OpenAIRE

    S. C. Neubauer; R. B. Franklin; D. J. Berrier

    2013-01-01

    Environmental perturbations in wetlands affect the integrated plant-microbial-soil system, causing biogeochemical responses that can manifest at local to global scales. The objective of this study was to determine how saltwater intrusion affects carbon mineralization and greenhouse gas production in coastal wetlands. Working with tidal freshwater marsh soils that had experienced roughly 3.5 yr of in situ saltwater additions, we quantified changes in soil properties, measured extracellu...

  15. Evaluating Southern Ocean Carbon Eddy-Pump From Biogeochemical-Argo Floats

    Science.gov (United States)

    Llort, Joan; Langlais, C.; Matear, R.; Moreau, S.; Lenton, A.; Strutton, Peter G.

    2018-02-01

    The vertical transport of surface water and carbon into ocean's interior, known as subduction, is one of the main mechanisms through which the ocean influences Earth's climate. New instrumental approaches have shown the occurrence of localized and intermittent subduction episodes associated with small-scale ocean circulation features. These studies also revealed the importance of such events for the export of organic matter, the so-called eddy-pump. However, the transient and localized nature of episodic subduction hindered its large-scale evaluation to date. In this work, we present an approach to detect subduction events at the scale of the Southern Ocean using measurements collected by biogeochemical autonomous floats (BGCArgo). We show how subduction events can be automatically identified as anomalies of spiciness and Apparent Oxygen Utilization (AOU) below the mixed layer. Using this methodology over more than 4,000 profiles, we detected 40 subduction events unevenly distributed across the Sothern Ocean. Events were more likely found in hot spots of eddy kinetic energy (EKE), downstream major bathymetric features. Moreover, the bio-optical measurements provided by BGCArgo allowed measuring the amount of Particulate Organic Carbon (POC) being subducted and assessing the contribution of these events to the total downward carbon flux at 100 m (EP100). We estimated that the eddy-pump represents less than 19% to the EP100 in the Southern Ocean, although we observed particularly strong events able to locally duplicate the EP100. This approach provides a novel perspective on where episodic subduction occurs that will be naturally improved as BGCArgo observations continue to increase.

  16. Potential effects of climate change and variability on watershed biogeochemical processes and water quality in Northeast Asia.

    Science.gov (United States)

    Park, Ji-Hyung; Duan, Lei; Kim, Bomchul; Mitchell, Myron J; Shibata, Hideaki

    2010-02-01

    An overview is provided of the potential effects of climate change on the watershed biogeochemical processes and surface water quality in mountainous watersheds of Northeast (NE) Asia that provide drinking water supplies for large populations. We address major 'local' issues with the case studies conducted at three watersheds along a latitudinal gradient going from northern Japan through the central Korean Peninsula and ending in southern China. Winter snow regimes and ground snowpack dynamics play a crucial role in many ecological and biogeochemical processes in the mountainous watersheds across northern Japan. A warmer winter with less snowfall, as has been projected for northern Japan, will alter the accumulation and melting of snowpacks and affect hydro-biogeochemical processes linking soil processes to surface water quality. Soils on steep hillslopes and rich in base cations have been shown to have distinct patterns in buffering acidic inputs during snowmelt. Alteration of soil microbial processes in response to more frequent freeze-thaw cycles under thinner snowpacks may increase nutrient leaching to stream waters. The amount and intensity of summer monsoon rainfalls have been increasing in Korea over recent decades. More frequent extreme rainfall events have resulted in large watershed export of sediments and nutrients from agricultural lands on steep hillslopes converted from forests. Surface water siltation caused by terrestrial export of sediments from these steep hillslopes is emerging as a new challenge for water quality management due to detrimental effects on water quality. Climatic predictions in upcoming decades for southern China include lower precipitation with large year-to-year variations. The results from a four-year intensive study at a forested watershed in Chongquing province showed that acidity and the concentrations of sulfate and nitrate in soil and surface waters were generally lower in the years with lower precipitation, suggesting year

  17. Biogeochemical processes and the diversity of Nhecolândia lakes, Brazil

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    Teodoro I. R Almeida

    2011-06-01

    Full Text Available The Pantanal of Nhecolândia, the world's largest and most diversified field of tropical lakes, comprises approximately 10,000 lakes, which cover an area of 24,000 km² and vary greatly in salinity, pH, alkalinity, colour, physiography and biological activity. The hyposaline lakes have variable pHs, low alkalinity, macrophytes and low phytoplankton densities. The saline lakes have pHs above 9 or 10, high alkalinity, a high density of phytoplankton and sand beaches. The cause of the diversity of these lakes has been an open question, which we have addressed in our research. Here we propose a hybrid process, both geochemical and biological, as the main cause, including (1 a climate with an important water deficit and poverty in Ca2+ in both superficial and phreatic waters; and (2 an elevation of pH during cyanobacteria blooms. These two aspects destabilise the general tendency of Earth's surface waters towards a neutral pH. This imbalance results in an increase in the pH and dissolution of previously precipitated amorphous silica and quartzose sand. During extreme droughts, amorphous silica precipitates in the inter-granular spaces of the lake bottom sediment, increasing the isolation of the lake from the phreatic level. This paper discusses this biogeochemical problem in the light of physicochemical, chemical, altimetric and phytoplankton data.O Pantanal da Nhecolândia é o maior e mais diversificado campo de lagos da região tropical do planeta, com cerca de 10.000 lagos de variadas salinidade, pH, alcalinidade, cor, fisiografia e atividade biológica dispostos em uma área de 24.000 km². Os lagos hipossalinos têm pH variável, baixa alcalinidade, macrófitas e baixa densidade de fitoplâncton. Os lagos salinos tem pH acima de 9 ou 10, elevada alcalinidade, alta densidade de fitoplâncton e praias de areia. A causa da diversidade desses lagos é uma questão ainda em aberto que é abordada nesta pesquisa. Propõe-se como principal causa um

  18. Coupled physical/biogeochemical modeling including O2-dependent processes in the Eastern Boundary Upwelling Systems: application in the Benguela

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    E. Gutknecht

    2013-06-01

    Full Text Available The Eastern Boundary Upwelling Systems (EBUS contribute to one fifth of the global catches in the ocean. Often associated with Oxygen Minimum Zones (OMZs, EBUS represent key regions for the oceanic nitrogen (N cycle. Important bioavailable N loss due to denitrification and anammox processes as well as greenhouse gas emissions (e.g, N2O occur also in these EBUS. However, their dynamics are currently crudely represented in global models. In the climate change context, improving our capability to properly represent these areas is crucial due to anticipated changes in the winds, productivity, and oxygen content. We developed a biogeochemical model (BioEBUS taking into account the main processes linked with EBUS and associated OMZs. We implemented this model in a 3-D realistic coupled physical/biogeochemical configuration in the Namibian upwelling system (northern Benguela using the high-resolution hydrodynamic ROMS model. We present here a validation using in situ and satellite data as well as diagnostic metrics and sensitivity analyses of key parameters and N2O parameterizations. The impact of parameter values on the OMZ off Namibia, on N loss, and on N2O concentrations and emissions is detailed. The model realistically reproduces the vertical distribution and seasonal cycle of observed oxygen, nitrate, and chlorophyll a concentrations, and the rates of microbial processes (e.g, NH4+ and NO2− oxidation, NO3− reduction, and anammox as well. Based on our sensitivity analyses, biogeochemical parameter values associated with organic matter decomposition, vertical sinking, and nitrification play a key role for the low-oxygen water content, N loss, and N2O concentrations in the OMZ. Moreover, the explicit parameterization of both steps of nitrification, ammonium oxidation to nitrate with nitrite as an explicit intermediate, is necessary to improve the representation of microbial activity linked with the OMZ. The simulated minimum oxygen

  19. Structure of peat soils and implications for biogeochemical processes and hydrological flow

    Science.gov (United States)

    Rezanezhad, F.; McCarter, C. P. R.; Gharedaghloo, B.; Kleimeier, C.; Milojevic, T.; Liu, H.; Weber, T. K. D.; Price, J. S.; Quinton, W. L.; Lenartz, B.; Van Cappellen, P.

    2017-12-01

    Permafrost peatlands contain globally important amounts of soil organic carbon and play major roles in global water, nutrient and biogeochemical cycles. The structure of peatland soils (i.e., peat) are highly complex with unique physical and hydraulic properties; where significant, and only partially reversible, shrinkage occurs during dewatering (including water table fluctuations), compression and/or decomposition. These distinct physical and hydraulic properties controls water flow, which in turn affect reactive and non-reactive solute transport (such as, sorption or degradation) and biogeochemical functions. Additionally, peat further attenuates solute migration through molecular diffusion into the inactive pores of Sphagnum dominated peat. These slow, diffusion-limited solute exchanges between the pore regions may give rise to pore-scale chemical gradients and heterogeneous distributions of microbial habitats and activity in peat soils. Permafrost peat plateaus have the same essential subsurface characteristics as other widely organic soil-covered peatlands, where the hydraulic conductivity is related to the degree of decomposition and soil compression. Increasing levels of decomposition correspond with a reduction of effective pore diameter and consequently restrict water and solute flow (by several orders of magnitude in hydraulic conductivity between the ground surface and a depth of 50 cm). In this presentation, we present the current knowledge of key physical and hydraulic properties related to the structure of globally available peat soils and discuss their implications for water storage, flow and the migration of solutes.

  20. Spatial patterns in soil biogeochemical process rates along a Louisiana wetland salinity gradient in the Barataria Bay estuarine system

    Science.gov (United States)

    Roberts, B. J.; Rich, M. W.; Sullivan, H. L.; Bledsoe, R.; Dawson, M.; Donnelly, B.; Marton, J. M.

    2014-12-01

    Louisiana has the highest rates of coastal wetland loss in the United States. In addition to being lost, Louisiana wetlands experience numerous other environmental stressors including changes in salinity regime (both increases from salt water intrusion and decreases from the creation of river diversions) and climate change induced changes in vegetation (e.g. the northward expansion of Avicennia germinans (black mangrove) into salt marshes). In this study, we examined how these changes might influence biogeochemical process rates important in regulating carbon balance and the cycling, retention, and removal of nutrients in Louisiana wetlands. Specifically, we measured net soil greenhouse gas fluxes and collected cores for the determination of rates of greenhouse gas production, denitrification potential, nitrification potential, iron reduction, and phosphorus sorption from surface (0-5cm) and subsurface (10-15cm) depths for three plots in each of 4 sites along the salinity gradient: a freshwater marsh site, a brackish (7 ppt) marsh site, a salt marsh (17 ppt), and a Avicennia germinans stand (17 ppt; adjacent to salt marsh site) in the Barataria Bay estuarine system. Most biogeochemical processes displayed similar spatial patterns with salt marsh rates being lower than rates in freshwater and/or brackish marsh sites and not having significantly different rates than in Avicennia germinans stands. Rates in surface soils were generally higher than in subsurface soils. These patterns were generally consistent with spatial patterns in soil properties with soil water content, organic matter quantity and quality, and extractable nutrients generally being higher in freshwater and brackish marsh sites than salt marsh and Avicennia germinans sites, especially in surface soils. These spatial patterns suggest that the ability of coastal wetlands to retain and remove nutrients might change significantly in response to future climate changes in the region and that these

  1. Dynamic modeling of nitrogen losses in river networks unravels the coupled effects of hydrological and biogeochemical processes

    Science.gov (United States)

    Alexander, Richard B.; Böhlke, John Karl; Boyer, Elizabeth W.; David, Mark B.; Harvey, Judson W.; Mulholland, Patrick J.; Seitzinger, Sybil P.; Tobias, Craig R.; Tonitto, Christina; Wollheim, Wilfred M.

    2009-01-01

    The importance of lotic systems as sinks for nitrogen inputs is well recognized. A fraction of nitrogen in streamflow is removed to the atmosphere via denitrification with the remainder exported in streamflow as nitrogen loads. At the watershed scale, there is a keen interest in understanding the factors that control the fate of nitrogen throughout the stream channel network, with particular attention to the processes that deliver large nitrogen loads to sensitive coastal ecosystems. We use a dynamic stream transport model to assess biogeochemical (nitrate loadings, concentration, temperature) and hydrological (discharge, depth, velocity) effects on reach-scale denitrification and nitrate removal in the river networks of two watersheds having widely differing levels of nitrate enrichment but nearly identical discharges. Stream denitrification is estimated by regression as a nonlinear function of nitrate concentration, streamflow, and temperature, using more than 300 published measurements from a variety of US streams. These relations are used in the stream transport model to characterize nitrate dynamics related to denitrification at a monthly time scale in the stream reaches of the two watersheds. Results indicate that the nitrate removal efficiency of streams, as measured by the percentage of the stream nitrate flux removed via denitrification per unit length of channel, is appreciably reduced during months with high discharge and nitrate flux and increases during months of low-discharge and flux. Biogeochemical factors, including land use, nitrate inputs, and stream concentrations, are a major control on reach-scale denitrification, evidenced by the disproportionately lower nitrate removal efficiency in streams of the highly nitrate-enriched watershed as compared with that in similarly sized streams in the less nitrate-enriched watershed. Sensitivity analyses reveal that these important biogeochemical factors and physical hydrological factors contribute nearly

  2. Using Stable Isotopes to Link Nutrient Sources in the Everglades and Biological Sinks in Florida Bay: A Biogeochemical Approach to Evaluate Ecosystem Response to Changing Nutrient Regimes

    Science.gov (United States)

    Hoare, A. M.; Hollander, D. J.; Heil, C.; Glibert, P.; Murasko, S.; Revilla, M.; Alexander, J.

    2005-05-01

    stable isotopic measurements are important tools in determining nutrient source and biogeochemical processing in these ecosystems and can be used to evaluate future ecological responses to hydrologic restoration.

  3. Biogeochemical processes in the continental slope of Bay of Bengal: I. Bacterial solubilization of inorganic phosphate

    Directory of Open Access Journals (Sweden)

    Surajit Das

    2007-03-01

    Full Text Available Microorganisms play a vital role in the biogeochemical cycles of various marine environments, but studies on occurrence and distribution of such bacteria in the marine environment from India are meager. We studied the phosphate solubilizing property of bacteria from the deep sea sediment of Bay of Bengal, India, to understand their role in phosphorous cycle (and thereby the benthic productivity of the deep sea environment. Sediment samples were obtained from 33 stations between 10°36’ N - 20°01’ N and 79°59’ E - 87°30’ E along 11 transects at 3 different depths i.e. ca. 200 m, 500 m, 1000 m in each transect. Total heterotrophic bacterial (THB counts ranged from 0.42 to 37.38x10(4 CFU g-1 dry sediment weight. Of the isolates tested, 7.57% showed the phosphate solubilizing property. The phosphate solubilizing bacterial genera were Pseudomonas, Bacillus, Vibrio, Alcaligenes, Micrococcus, Corynebacterium and Flavobacterium. These strains are good solubilizers of phosphates which ultimately may play a major role in the biogeochemical cycle and the benthic productivity of the Exclusive Economic Zone (EEZ of Bay of Bengal, because this enzyme is important for the slow, but steady regeneration of phosphate and organic carbon in the deep sea. Rev. Biol. Trop. 55 (1: 1-9. Epub 2007 March. 31.Estudiamos la capacidad que tienen las bacterias de sedimentos profundos en la Bahía de Bengala, India, de disolver los fosfatos que juegan un papel clave en los ciclos biogeoquímicos del mar. Recolectamos muestras en 33 estaciones ubicadas entre 10°36’N - 20°01’N y 79°59’E - 87°30’E en once transectos y tres profundidades, i.e. ca. 200 m, 500 m, 1000 m. Los conteos totales de bacterias heterotróficas fueron de 0.42 a 37.38x10(4 CFU g-1 (peso seco de sedimento. De las cepas evaluadas, un 7.57% disuelven fosfato. Los géneros con esta características fueron Pseudomonas, Bacillus, Vibrio, Alcaligenes, Micrococcus, Corynebacterium y

  4. The two-layer geochemical structure of modern biogeochemical provinces and its significance for spatially adequate ecological evaluations and decisions

    Science.gov (United States)

    Korobova, Elena; Romanov, Sergey

    2014-05-01

    Contamination of the environment has reached such a scale that ecogeochemical situation in any area can be interpreted now as a result of the combined effect of natural and anthropogenic factors. The areas that appear uncomfortable for a long stay can have natural and anthropogenic genesis, but the spatial structure of such biogeochemical provinces is in any case formed of a combination of natural and technogenic fields of chemical elements. Features of structural organization and the difference in factors and specific time of their formation allow their separation on one hand and help in identification of areas with different ecological risks due to overlay of the two structures on the other. Geochemistry of soil cover reflects the long-term result of the naturally balanced biogeochemical cycles, therefore the soil geochemical maps of the undisturbed areas may serve the basis for evaluation of the natural geochemical background with due regard to the main factors of geochemical differentiation in biosphere. Purposeful and incidental technogenic concentrations and dispersions of chemical elements of specific (mainly mono- or polycentric) structure are also fixed in soils that serve as secondary sources of contamination of the vegetation cover and local food chains. Overlay of the two structures forms specific heterogeneity of modern biogeochemical provinces with different risk for particular groups of people, animals and plants adapted to specific natural geochemical background within particular concentration interval. The developed approach is believed to be helpful for biogeochemical regionalizing of modern biosphere (noosphere) and for spatially adequate ecogeochemical evaluation of the environment and landuse decisions. It allows production of a set of applied geochemical maps such as: 1) health risk due to chemical elements deficiency and technogenic contamination accounting of possible additive effects; 2) adequate soil fertilization and melioration with due

  5. Evaluating the Terrestrial Biogeochemical Responses and Feedbacks of Stratospheric Geoengineering Strategies

    Science.gov (United States)

    Yang, C. E.; Hoffman, F. M.; Fu, J. S.

    2017-12-01

    Stratospheric aerosol geoengineering options, involving injection of sulfur dioxide (SO2) aerosols into the stratosphere, are being proposed to reduce the heating effects of increasing anthropogenic atmospheric carbon dioxide (CO2). While the impacts of stratospheric aerosol geoengineering on climate changes, such as stratospheric ozone depletion and weakened monsoons, have been extensively investigated in the past few decades, few studies have considered the biogeochemical (BGC) responses and feedbacks on land. Previous Earth system model (ESM) simulations incorporating stratospheric aerosol geoengineering scenarios primarily focused on the atmospheric radiative forcing and temperature response in the absence of ocean and land responses. The land model setup in these simulations did not incorporate the carbon-nitrogen cycles and effects on the hydrological cycle considering vegetation responses. Since ESMs simulated very different aerosol distributions for the G3 and G4 scenarios in the Geoengineering Model Intercomparison Project (GeoMIP), we instead adopted the G4SSA scenario to simulate the BGC responses and feedbacks on land due to stratospheric aerosol geoengineering using the Community Earth System Model with active biogeochemical dynamic variations enabled. Implications for the terrestrial carbon cycle and hydrological responses will be presented.

  6. Importance of biogeochemical processes in modeling stream chemistry in two watersheds in the Sierra Nevada, California

    Science.gov (United States)

    Meixner, Thomas; Brown, Aaron; Bales, Roger C.

    1998-11-01

    Two small (0.22 and 0.48 ha) alpine watersheds in the Sierra Nevada of California were studied during the 1992 and 1993 snowmelt seasons to evaluate the importance of soil properties and processes on chemical concentrations in the discharges from each watershed. Watershed 1 was surveyed as having 26% soil cover, whereas watershed 2 was 10% soil covered. Watershed 2 had greater H+ and nitrogen consumption than watershed 1 but similar cation and sulfate concentrations despite having one fourth the surveyed soil volume per unit area as watershed 1. Daily stream concentrations simulated with the Alpine Hydrochemical Model (AHM) matched the data well, after a systematic model calibration with a subset of the data. We found that the structure of the AHM and the hydrologic parameters developed for the nearby 1.2 km2 Emerald Lake watershed could be applied to these watersheds with only small adjustments; chemical parameters required considerably more adjustment, reflecting a greater degree of chemical versus physical heterogeneity at this scale. Calibration for watershed 2 gave a higher percent base saturation (19 versus 4%) and lower streamversus 10-2.6 atm) than for watershed 1 and three times the soil reactivity (expected) of a field survey. Areas mapped as exposed bedrock in the catchments apparently contributed cations and alkalinity to stream water to a greater extent than did neighboring areas of soil. Areas of exposed bedrock were a larger nitrogen sink than the adjoining areas of soil. The pH and acid-neutralizing capacity of surface runoff in both catchments were less sensitive to changes in atmospheric deposition than at the nearby Emerald Lake watershed. This decreased sensitivity was due to (1) a less pronounced ionic pulse, (2) less retention of sulfate in the soil, and (3) greater nitrate retention.

  7. The influence of biogeochemical processes on the pH dynamics in the seasonally hypoxic saline Lake Grevelingen, The Netherlands

    Science.gov (United States)

    Hagens, Mathilde; Slomp, Caroline; Meysman, Filip; Borges, Alberto; Middelburg, Jack

    2013-04-01

    Coastal areas experience more pronounced short-term fluctuations in pH than the open ocean due to higher rates of biogeochemical processes such as primary production, respiration and nitrification. These processes and changes therein can mask or amplify the ocean acidification signal induced by increasing atmospheric pCO2. Coastal acidification can be enhanced when eutrophication-induced hypoxia develops. This is because the carbon dioxide produced during respiration leads to a decrease in the buffering capacity of the hypoxic bottom water. Saline Lake Grevelingen (SW Netherlands) has limited water exchange with the North Sea and experiences seasonal bottom water hypoxia, which differs in severity interannually. Hence this lake provides an ideal site to study how coastal acidification is affected by seasonal hypoxia. We examined the annual cycle of the carbonate system in Lake Grevelingen in 2012 and how biogeochemical processes in the water column impact it. Monthly measurements of all carbonate system parameters (DIC, pH, fCO2 and TA), suspended matter, oxygen and nutrients were accompanied by measurements of primary production and respiration using O2 light-dark incubations. Primary production was also estimated every season using 14C-incubations and monthly via 13C-labeling of phospholipid-derived fatty acids (PLFA). Finally, incubations to estimate nitrification and NH4 uptake using 15N-enriched ammonium were carried out seasonally. Preliminary results show that the hypoxic period was rather short in 2012. During stratification and hypoxia, pH varied by up to 0.75 units between the oxic surface water and the hypoxic bottom water. Consistency calculations of the carbonate system reveal that pH is best computed using DIC and TA and that there is no significant difference between TA measured on filtered (0.45 μm) and unfiltered samples. Primary production rates were highest in summer and range up to 800 mmol C/m2/d. Nitrification rates varied between 73

  8. Variability of atmospheric greenhouse gases as a biogeochemical processing signal at regional scale in a karstic ecosystem

    Science.gov (United States)

    Borràs, Sílvia; Vazquez, Eusebi; Morguí, Josep-Anton; Àgueda, Alba; Batet, Oscar; Cañas, Lídia; Curcoll, Roger; Grossi, Claudia; Nofuentes, Manel; Occhipinti, Paola; Rodó, Xavier

    2015-04-01

    The South-eastern area of the Iberian Peninsula is an area where climatic conditions reach extreme climatic conditions during the year, and is also heavily affected by the ENSO and NAO. The Natural Park of Cazorla, Segura de la Sierra and Las Villas is located in this region, and it is the largest protected natural area in Spain (209920 Ha). This area is characterized by important climatic and hydrologic contrasts: although the mean annual precipitation is 770 nm, the karstic soils are the main cause for water scarcity during the summer months, while on the other hand it is in this area where the two main rivers of Southern Spain, the Segura and the Guadalquivir, are born. The protected area comprises many forested landscapes, karstic areas and reservoirs like Tranco de Beas. The temperatures during summer are high, with over 40°C heatwaves occurring each year. But during the winter months, the land surface can be covered by snow for periods of time up until 30 days. The ENSO and NAO influences cause also an important inter annual climatic variability in this area. Under the ENSO, autumnal periods are more humid while the following spring is drier. In this area vegetal Mediterranean communities are dominant. But there are also a high number of endemic species and derelict species typical of temperate climate. Therefore it is a protected area with high specific diversity. Additionally, there is an important agricultural activity in the fringe areas of the Natural Park, mainly for olive production, while inside the Park this activity is focused on mountain wheat production. Therefore the diverse vegetal communities and landscapes can easily be under extreme climatic pressures, affecting in turn the biogeochemical processes at the regional scale. The constant, high-frequency monitoring of greenhouse gases (GHG) (CO2 and CH4) integrates the biogeochemical signal of changes in this area related to the carbon cycle at the regional scale, capturing the high diversity of

  9. Regional application of process based biogeochemical model DNDC in Godavari Sub-basin

    Directory of Open Access Journals (Sweden)

    A Biswal

    2016-12-01

    Full Text Available The denitrification decomposition (DNDC model is a process-based computer simulation model of soil carbon and nitrogen biogeochemistry. The DNDC model is one of the few process-based bio-geo chemical crop simulation models for which both a site-specific mode and a regional mode were developed. For regional mode, a region is presented in a typical Geographic Information System (GIS consisting of many polygons or grid cells. The database consists of spatially differentiated information of location, climate, soil properties, cropping systems, and farm management practices for each polygon or grid cell for the entire modeled region. An attempt was made to establish the methodology for the estimation of soil greenhouse gas fluxes like CH4, CO2 and N2O on a sub-basin scale.

  10. New HYDRUS Modules for Simulating Preferential Flow, Colloid-Facilitated Contaminant Transport, and Various Biogeochemical Processes in Soils

    Science.gov (United States)

    Simunek, J.; Sejna, M.; Jacques, D.; Langergraber, G.; Bradford, S. A.; van Genuchten, M. Th.

    2012-04-01

    We have dramatically expanded the capabilities of the HYDRUS (2D/3D) software package by developing new modules to account for processes not available in the standard HYDRUS version. These new modules include the DualPerm, C-Hitch, HP2/3, Wetland, and Unsatchem modules. The dual-permeability modeling approach of Gerke and van Genuchten [1993] simulating preferential flow and transport is implemented into the DualPerm module. Colloid transport and colloid-facilitated solute transport, the latter often observed for many contaminants, such as heavy metals, radionuclides, pharmaceuticals, pesticides, and explosives [Šimůnek et al., 2006] are implemented into the C-Hitch module. HP2 and HP3 are the two and three-dimensional alternatives of the HP1 module, currently available with HYDRUS-1D [Jacques and Šimůnek, 2005], that couple HYDRUS flow and transport routines with the generic geochemical model PHREEQC of Parkhurst and Appelo [1999]. The Wetland module includes two alternative approaches (CW2D of Langergraber and Šimůnek [2005] and CWM1 of Langergraber et al. [2009]) for modeling aerobic, anaerobic, and anoxic biogeochemical processes in natural and constructed wetlands. Finally, the Unsatchem module simulates the transport and reactions of major ions in a soil profile. Brief descriptions and an application of each module will be presented. Except for HP3, all modules simulate flow and transport processes in two-dimensional transport domains. All modules are fully supported by the HYDRUS graphical user interface. Further development of these modules, as well as of several other new modules (such as Overland), is still envisioned. Continued feedback from the research community is encouraged.

  11. Environmental Transport of Plutonium: Biogeochemical Processes at Femtomolar Concentrations and Nanometer Scales

    Energy Technology Data Exchange (ETDEWEB)

    Kersting, Annie B. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2010-10-05

    The major challenge in predicting the mobility and transport of plutonium (Pu) is determining the dominant geochemical processes that control its behavior in the subsurface. The reaction chemistry of Pu (i.e., aqueous speciation, solubility, sorptivity, redox chemistry, and affinity for colloidal particles, both abiotic and microbially mediated) is particularly complicated. It is generally thought that due to its low solubility and high sorptivity, Pu migration in the environment occurs only when facilitated by transport on particulate matter (i.e., colloidal particles). Despite the recognized importance of colloid-facilitated transport of Pu, very little is known about the geochemical and biochemical mechanisms controlling Pu-colloid formation and association, particularly at femtomolar Pu concentrations observed at DOE sites.

  12. Biogeochemical processes controlling authigenic carbonate formation within the sediment column from the Okinawa Trough

    Science.gov (United States)

    Li, Jiwei; Peng, Xiaotong; Bai, Shijie; Chen, Zhiyan; Van Nostrand, Joy D.

    2018-02-01

    Authigenic carbonates are one type of conspicuous manifestation in seep environments that can provide long-term archives of past seepage activity and methane cycling in the oceans. Comprehensive investigations of the microbial community functional structure and their roles in the process of carbonate formation are, however, lacking. In this study, the mineralogical, geochemical, and microbial functional composition were examined in seep carbonate deposits collected from the west slope of the northern section of the Okinawa Trough (OT). The aim of this work was to explore the correspondence between the mineralogical phases and microbial metabolism during carbonate deposit formation. The mineralogical analyses indicated that authigenic carbonate minerals (aragonite, magnesium-rich calcite, dolomite, ankerite and siderite) and iron-bearing minerals (limonite, chlorite, and biotite) were present in these carbonate samples. The carbon and oxygen isotopic values of the carbonate samples varied between -51.1‰ to -4.7‰ and -4.8‰ to 3.7‰, respectively. A negative linear correlation between carbon and oxygen isotopic compositions was found, indicating a mixture of methane-derived diagenetic (low δ13C/high 18O) carbonates and detrital origin (high δ13C/low 18O) carbonates at the OT. GeoChip analyses suggested that various metabolic activities of microorganisms, including methanogenesis, methane oxidation, sulfite oxidation, sulfate reduction, and metal biotransformations, all occurred during the formation process. On the basis of these findings, the following model for the methane cycle and seep carbonate deposit formation in the sediment column at the OT is proposed: (1) in the upper oxidizing zone, aerobic methane oxidation was the main way of methane consumption; (2) in the sulfate methane transition zone, sulfate-dependent AOM (anaerobic oxidation of methane) consumes methane, and authigenic minerals such as aragonite, magnesium-calcite, and sulfide minerals

  13. Towards the understanding of biogeochemical processes involved in the release of carbonyl sulfide (COS) from soil

    Science.gov (United States)

    Behrendt, Thomas; Catao, Elisa; Bunk, Rüdiger; Yi, Zhigang; Greule, Markus; Keppler, Frank; Kesselmeier, Jürgen; Trumbore, Susan

    2017-04-01

    Carbonyl sulfide (COS) is present in the atmosphere in low mixing ratio ( 500ppt). It is relevant in climate change through the effect in aerosol formation. Soils can act as source of COS, e.g. by microbial degradation of thiocyanate from plant material. On the other side it is known that COS can be consumed via various enzymatic pathways. Assuming that biogenic processes dominate over chemical reactions we extracted nucleic acids and performed amplicon sequencing for bacteria (16S rRNA) and fungi (ITS region) from a mid-latitude agricultural maize soil which was previously incubated under ambient COS and COS fumigation ( 1000ppt). The mixing ratios of COS have been measured online from soil samples in a dynamic chamber system under laboratory conditions by an integrated cavity output spectroscopy (IOCS) analyzer (Los Gatos Research Inc., USA). Additionally stable carbon isotope values (δ13C values) of COS were measured using a pre-concentration method and stable isotope ratio mass spectrometry (IRMS). Under low COS mixing ratio ( 50ppt) δ13C +4.7 ‰ for spruce forest ( 23°C), and -24.4‰ for mid-latitude cornfield ( 22°C), respectively. Linking gas release rates of (COS, CO2, CO, NO) to isotopic signatures of COS and molecular results might allow us to indicate bacterial s-compound degradation related to the higher activity of β-Proteobacteria and of the family Acetobacteraceae from the α-Proteobacteria phylum, potentially involved with the hydrolysis of thiocyanate in the soil releasing COS. Furthermore, our study reports the first COS data for rainforest and desert soils which are in the order of 0.5 pmol gdw-1 h-1 and 2 pmol gdw-1 h-1, respectively.

  14. An Analytical Particle Biogeochemical Sensor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Evaluation of the technical and scientific feasibility of developing a model and sensor for the analytical optical determination of particle biogeochemical...

  15. Process evaluation distributed system

    Science.gov (United States)

    Moffatt, Christopher L. (Inventor)

    2006-01-01

    The distributed system includes a database server, an administration module, a process evaluation module, and a data display module. The administration module is in communication with the database server for providing observation criteria information to the database server. The process evaluation module is in communication with the database server for obtaining the observation criteria information from the database server and collecting process data based on the observation criteria information. The process evaluation module utilizes a personal digital assistant (PDA). A data display module in communication with the database server, including a website for viewing collected process data in a desired metrics form, the data display module also for providing desired editing and modification of the collected process data. The connectivity established by the database server to the administration module, the process evaluation module, and the data display module, minimizes the requirement for manual input of the collected process data.

  16. Evaluation of heavy metal pollution in bogs of Tomsk region on change in biogeochemical activity of ericaceous shrubs

    Science.gov (United States)

    Gaskova, L. P.

    2018-01-01

    The article discusses the change in biogeochemical activity of plant species in bogs under the influence of various types of human impact (roads, cities, drainage of mires, fire). It has been established that ericaceous shrubs, depending on the species, react with varying degrees of intensity to anthropogenic influences. The biogeochemical activity of species increased by 2.5 to 4.8 times in polluted sites.

  17. Understanding the Relative Influence of Anthropogenic Versus Natural Nitrogen on Biogeochemical Processes in the Southern California Bight

    Science.gov (United States)

    McLaughlin, K.; Howard, M. D.; Beck, C. D. A.; Emler, L.; Nezlin, N. P.; Sutula, M.

    2016-02-01

    Nitrogen (N) pollution is considered to be one of the most significant consequences of human-accelerated global change on coastal oceans (Howarth and Marino 2006). In the southern California Bight, wastewater effluent represents 92% of total terrestrial N loading and these loads are equivalent to the "background" N flux from upwelling (Howard et al. 2014). In this study, we attempt to quantify the relative influence of the two dominant nitrogen sources to the Bight (wastewater effluent and upwelled nitrogen) on biogeochemical processes linked to dissolved oxygen, pH and algal blooms. We will compare the sources and fate of nitrogen in an effluent impacted region (offshore of Los Angeles and Orange Counties) to minimally-impacted regions both along the coastline (offshore of Northern San Diego County) and two offshore stations. Key rates of nitrogen and carbon cycling are measured, including primary production and respiration, nitrogen uptake by primary producers, and nitrification. Stable isotope tracer techniques have also been applied to determine the relative influence of effluent versus upwelled nitrogen on biological communities and concentrations. Data generated from this study will be used to validate calculated rate constants used in oceanographic models of ecological response from natural and anthropogenic nutrient inputs in the Bight. These models will be used to estimate the extent to which anthropogenic nutrients are affecting primary production, acidification and hypoxia, as well as which regions are most at risk. They will also be used to analyze management scenarios to understand the effects of anthropogenic nutrient load reductions relative to climate change scenarios.

  18. Investigating the Role of Biogeochemical Processes in the Northern High Latitudes on Global Climate Feedbacks Using an Efficient Scalable Earth System Model

    Energy Technology Data Exchange (ETDEWEB)

    Jain, Atul K. [Univ. of Illinois, Urbana-Champaign, IL (United States)

    2016-09-14

    The overall objectives of this DOE funded project is to combine scientific and computational challenges in climate modeling by expanding our understanding of the biogeophysical-biogeochemical processes and their interactions in the northern high latitudes (NHLs) using an earth system modeling (ESM) approach, and by adopting an adaptive parallel runtime system in an ESM to achieve efficient and scalable climate simulations through improved load balancing algorithms.

  19. MOPS-1.0: towards a model for the regulation of the global oceanic nitrogen budget by marine biogeochemical processes

    Directory of Open Access Journals (Sweden)

    I. Kriest

    2015-09-01

    Analysis of the model misfit with respect to observed biogeochemical tracer distributions and fluxes suggests a particle flux profile close to the one suggested by Martin et al. (1987. Simulated pelagic denitrification best agrees with the lower values between 59 and 84 Tg N yr−1 recently estimated by other authors.

  20. Study of the seasonal cycle of the biogeochemical processes in the Ligurian Sea using a 1D interdisciplinary model

    NARCIS (Netherlands)

    Raick, C.; Delhez, E.J.M.; Soetaert, K.E.R.; Grégoire, M.

    2005-01-01

    A one-dimensional coupled physical–biogeochemical model has been built to study the pelagic food web of the Ligurian Sea (NW Mediterranean Sea). The physical model is the turbulent closure model (version 1D) developed at the GeoHydrodynamics and Environmental Laboratory (GHER) of the University of

  1. Coupled hydrological and biogeochemical processes controlling variability of nitrogen species in streamflow during autumn in an upland forest

    Science.gov (United States)

    Stephen D. Sebestyen; James B. Shanley; Elizabeth W. Boyer; Carol Kendall; Daniel H. Doctor

    2014-01-01

    Autumn is a season of dynamic change in forest streams of the northeastern United States due to effects of leaf fall on both hydrology and biogeochemistry. Few studies have explored how interactions of biogeochemical transformations, various nitrogen sources, and catchment flow paths affect stream nitrogen variation during autumn. To provide more information on this...

  2. Useless arithmetic or useful scientific tools? Evaluation of the current state and future perspectives of aquatic biogeochemical modeling

    Science.gov (United States)

    Arhonditsis, G.

    2009-04-01

    What is the capacity of the current models to simulate the dynamics of environmental systems? How carefully do modelers develop their models? Which model features primarily determine our decision to utilize a specific model? How rigorously do we assess what a model can or cannot predict? The first part of my presentation is to answer some of these questions by reviewing the state of aquatic biogeochemical modeling; a research tool that has been extensively used for understanding and quantitatively describing aquatic ecosystems. Mechanistic aquatic biogeochemical models have form the scientific basis for environmental management decisions by providing a predictive link between management actions and ecosystem response; they have provided an important tool for elucidating the interactions between climate variability and plankton communities, and thus for addressing questions regarding the pace and impacts of climate change. The sizable number of aquatic ecosystem modeling studies which successfully passed the scrutiny of the peer-review process along with the experience gained from addressing a breadth of management problems can objectively reveal the systematic biases, methodological inconsistencies, and common misconceptions characterizing the modeling practice in environmental science. My arguments are that (i) models are not always developed in a consistent manner, clearly stated purpose, and predetermined acceptable model performance level, (ii) the potential "customers" select models without properly assessing their technical value, and (iii) oceanic modeling is a dynamic area of the current modeling practice whereas, model application for addressing environmental management issues on a local scale faces challenges as a scientific tool. The second part of my presentation argues that (i) the development of novel methods for rigorously assessing the uncertainty underlying model predictions should be a top priority of the modeling community, and (ii) the model

  3. Hydro-biogeochemical phosphorus mobilization - evaluating a wetland restoration "P risk" assesment tool

    DEFF Research Database (Denmark)

    Kjærgaard, Charlotte; Forsmann, Ditte M.; Hoffmann, Carl Christian

    2012-01-01

    a P risk assessment tool to predict the potential risk of P release following restoration of wetlands on former agricultural lowlands. Batch incubation experiments investigating changes in soil-water concentrations of PO4-P, total P and total dissolved Fe as a function of time after rewetting in 31...... as a risk assessment tool to predict the potential risk of P losses following wetland restoration. Based on new experiments simulating the continuous upward percolation of groundwater in selected intact soil cores we investigated the hydrobiogeochemical mobilization of phosphorus during variable flow...... conditions. Soil redox conditions and hydrology turned out as major factors controlling 109 phosphorus release. The presentation will focus on an evaluation of the P risk assessment tool based on data form the continuous flow experiment....

  4. Detecting synoptic changes in biogeochemical processes from high-dimensional data streams: a combined approach of time-series decomposition and nonlinear dimensionality reduction

    Science.gov (United States)

    Mahecha, M. D.; Jung, M.; von Buttlar, J.; Zscheischler, J.; Carvalhais, N.; Reichstein, M.

    2012-12-01

    The exchange fluxes of CO2, H2O, and energy between the land surface and the atmosphere are good indicators for changes within terrestrial ecosystems and crucial determinants for the development of the atmospheric composition. Today we are equipped with remote sensing and meteorological observations, as well as with a novel generation of quasi-observational data on global biosphere-atmosphere exchanges. In order to gain a profound understanding of terrestrial biogeochemical cycles, it is highly relevant to monitor the spatiotemporal variability and detect abrupt changes in any of those data streams. However, the question how to efficiently explore this very complete (though high dimensional) picture of the biogeochemical activity on the land surface is one of the major challenges in global environmental research. Here, we illustrate a combination of time-series decomposition and nonlinear dimensionality reduction technique methods for scrutinizing the underlying scales of variability. Further, we discuss the question how to extract a low-dimensional biosphere-atmosphere-index that indicates and quantifies changes in any relevant dimension. Overall, the idea is to provide a fully data driven guideline for biogeochemical interpretations that may also serve as reference for the evaluation of state-of-the-art land-surface models.

  5. Statistical evaluation of biogeochemical variables affecting spatiotemporal distributions of multiple free metal ion concentrations in an urban estuary.

    Science.gov (United States)

    Dong, Zhao; Lewis, Christopher G; Burgess, Robert M; Coull, Brent; Shine, James P

    2016-05-01

    Free metal ion concentrations have been recognized as a better indicator of metal bioavailability in aquatic environments than total dissolved metal concentrations. However, our understanding of the determinants of free ion concentrations, especially in a metal mixture, is limited, due to underexplored techniques for measuring multiple free metal ions simultaneously. In this work, we performed statistical analyses on a large dataset containing repeated measurements of free ion concentrations of Cu, Zn, Pb, Ni, and Cd, the most commonly measured metals in seawater, at five inshore locations in Boston Harbor, previously collected using an in-situ equilibrium-based multi-metal free ion sampler, the 'Gellyfish'. We examined correlations among these five metals by season, and evaluated effects of 10 biogeochemical variables on free ion concentrations over time and location through multivariate regressions. We also explored potential clustering among the five metals through a principal component analysis. We found significant correlations among metals, with varying patterns over season. Our regression results suggest that instead of dissolved metals, pH, salinity, temperature and rainfall were the most significant determinants of free metal ion concentrations. For example, a one-unit decrease in pH was associated with a 2.2 (Cd) to 99 (Cu) times increase in free ion concentrations. This work is among the first to reveal key contributors to spatiotemporal variations in free ion concentrations, and demonstrated the usefulness of the Gellyfish sampler in routine sampling of free ions within metal mixtures and in generating data for statistical analyses. Copyright © 2016. Published by Elsevier Ltd.

  6. Supplier Evaluation Processes

    DEFF Research Database (Denmark)

    Hald, Kim Sundtoft; Ellegaard, Chris

    2011-01-01

    in the evaluation process. Design/methodology/approach – The paper relies on a multiple, longitudinal case research methodology. The two cases show two companies' efforts in designing, implementing, and using supplier evaluation in order to improve supplier performance. Findings – The findings show how the dynamics...... thereby improving their effects. Managers must know how performance information is altered before reaching key supplier actors in order to optimise supplier performance. Originality/value – Current studies on supplier evaluation practices are limited in their focus on design, implementation, or use......Purpose – The purpose of this paper is to illuminate how supplier evaluation practices are linked to supplier performance improvements. Specifically, the paper investigates how performance information travelling between the evaluating buyer and the evaluated suppliers is shaped and reshaped...

  7. Simulating temporal variations of nitrogen losses in river networks with a dynamic transport model unravels the coupled effects of hydrological and biogeochemical processes

    Energy Technology Data Exchange (ETDEWEB)

    Mulholland, Patrick J [ORNL; Alexander, Richard [U.S. Geological Survey; Bohlke, John [U.S. Geological Survey; Boyer, Elizabeth [Pennsylvania State University; Harvey, Judson [U.S. Geological Survey; Seitzinger, Sybil [Rutgers University; Tobias, Craig [University of North Carolina, Wilmington; Tonitto, Christina [Cornell University; Wollheim, Wilfred [University of New Hampshire

    2009-01-01

    The importance of lotic systems as sinks for nitrogen inputs is well recognized. A fraction of nitrogen in streamflow is removed to the atmosphere via denitrification with the remainder exported in streamflow as nitrogen loads. At the watershed scale, there is a keen interest in understanding the factors that control the fate of nitrogen throughout the stream channel network, with particular attention to the processes that deliver large nitrogen loads to sensitive coastal ecosystems. We use a dynamic stream transport model to assess biogeochemical (nitrate loadings, concentration, temperature) and hydrological (discharge, depth, velocity) effects on reach-scale denitrification and nitrate removal in the river networks of two watersheds having widely differing levels of nitrate enrichment but nearly identical discharges. Stream denitrification is estimated by regression as a nonlinear function of nitrate concentration, streamflow, and temperature, using more than 300 published measurements from a variety of US streams. These relations are used in the stream transport model to characterize nitrate dynamics related to denitrification at a monthly time scale in the stream reaches of the two watersheds. Results indicate that the nitrate removal efficiency of streams, as measured by the percentage of the stream nitrate flux removed via denitrification per unit length of channel, is appreciably reduced during months with high discharge and nitrate flux and increases during months of low-discharge and flux. Biogeochemical factors, including land use, nitrate inputs, and stream concentrations, are a major control on reach-scale denitrification, evidenced by the disproportionately lower nitrate removal efficiency in streams of the highly nitrate-enriched watershed as compared with that in similarly sized streams in the less nitrate-enriched watershed. Sensitivity analyses reveal that these important biogeochemical factors and physical hydrological factors contribute nearly

  8. Contributions of physical and biogeochemical processes to phytoplankton biomass enhancement in the surface and subsurface layers during the passage of Typhoon Damrey

    Science.gov (United States)

    Pan, Shanshan; Shi, Jie; Gao, Huiwang; Guo, Xinyu; Yao, Xiaohong; Gong, Xiang

    2017-01-01

    In this study, a one-dimensional physical-biogeochemical coupled model was established to investigate the responses of the upper ocean to Typhoon Damrey in the basin area of the South China Sea. The surface chlorophyll a concentration (Chl a) increased rapidly from 0.07 to 0.17 mg m-3 when the typhoon arrived and then gradually reached a peak of 0.61 mg m-3 after the typhoon's passage. The subsurface Chl a decreased from 0.34 to 0.17 mg m-3 as the typhoon arrived and then increased gradually to 0.71 mg m-3. Analyses of model results indicated that the initial rapid increase in the surface Chl a and the decrease in the subsurface Chl a were caused mainly by physical process (vertical mixing), whereas the subsequent gradual increases in the Chl a in both the surface and subsurface layers were due mainly to biogeochemical processes (net growth of phytoplankton). The gradual increase in the Chl a lasted for longer in the subsurface layer than in the surface layer. Typhoon Damrey yielded an integrated primary production (IPP) of 6.5 × 103 mg C m-2 ( 14% of the annual IPP in this region).

  9. Isoprenoid quinones resolve the stratification of microbial redox processes in a biogeochemical continuum from the photic zone to deep anoxic sediments of the Black Sea.

    Science.gov (United States)

    Becker, Kevin W; Elling, Felix J; Schröder, Jan M; Lipp, Julius S; Goldhammer, Tobias; Zabel, Matthias; Elvert, Marcus; Overmann, Jörg; Hinrichs, Kai-Uwe

    2018-03-09

    The stratified water column of the Black Sea serves as a model ecosystem for studying the interactions of microorganisms with major biogeochemical cycles. Here we provide detailed analysis of isoprenoid quinones to study microbial redox processes in the ocean. In a continuum from the photic zone through the chemocline into deep anoxic sediments of the southern Black Sea, diagnostic quinones and inorganic geochemical parameters indicate niche segregation between redox processes and corresponding shifts in microbial community composition. Quinones specific for oxygenic photosynthesis and aerobic respiration dominate oxic waters, while quinones associated with thaumarchaeal ammonia-oxidation and bacterial methanotrophy, respectively, dominate a narrow interval in suboxic waters. Quinone distributions indicate highest metabolic diversity within the anoxic zone, with anoxygenic photosynthesis being a major process in its photic layer. In the dark anoxic layer, quinone profiles indicate occurrence of bacterial sulfur and nitrogen cycling, archaeal methanogenesis, and archaeal methanotrophy. Multiple novel ubiquinone isomers, possibly originating from unidentified intra-aerobic anaerobes, occur in this zone. The respiration modes found in the anoxic zone continue into shallow subsurface sediments, but quinone abundances rapidly decrease within the upper 50 cm below sea floor, reflecting the transition to lower energy availability. In the deep subseafloor sediments, quinone distributions and geochemical profiles indicate archaeal methanogenesis/methanotrophy and potentially bacterial fermentative metabolisms. We observed that sedimentary quinone distributions track lithology, which supports prior hypotheses that deep biosphere community composition and metabolisms are determined by environmental conditions during sediment deposition. Importance Microorganisms play crucial roles in global biogeochemical cycles. Yet, we have only a fragmentary understanding of the diversity

  10. Final Report DE-SC0006997; PI Sharp; Coupled Biological and Micro-XAS/XRF Analysis of In Situ Uranium Biogeochemical Processes

    Energy Technology Data Exchange (ETDEWEB)

    Sharp, Jonathan O. [Colorado School of Mines, Golden, CO (United States)

    2016-03-30

    Project Overview: The impact of the original seed award was substantially increased by leveraging a postdoctoral fellowship (Marie Curie Postdoctoral Fellowship) and parallel funds from (A) synergistic project supported by NSF and (B) with DOE collaborators (PI’s Ranville and Williams) as well as no-cost extension that greatly increased the impact and publications associated with the project. In aligning with SBR priorities, the project’s focus was extended more broadly to explore coupled biogeochemical analysis of metal (im)mobilization processes beyond uranium with a foundation in integrating microbial ecology with geochemical analyses. This included investigations of arsenic and zinc during sulfate reducing conditions in addition to direct microbial reduction of metals. Complimentary work with NSF funding and collaborative DOE interactions further increased the project scope to investigate metal (im)mobilization coupled to biogeochemical perturbations in forest ecosystems with an emphasis on coupled carbon and metal biogeochemistry. In total, the project was highly impactful and resulted in 9 publications and directly supported salary/tuition for 3 graduate students at various stages of their academic careers as well as my promotion to Associate Professor. In going forward, findings provided inspiration for a two subsequent proposals with collaborators at Lawrence Berkeley Laboratory and others that are currently in review (as of March 2016).

  11. Evaluation of innovation processes

    Directory of Open Access Journals (Sweden)

    Jakub Tabas

    2012-01-01

    Full Text Available In present, innovations are spoken as an engine of the world economy because the innovations are transforming not only business entities but the whole industries. The innovations have become a necessity for business entities in order to survive on floating challenging markets. This way, innovations are driving force of companies’ performance. The problem which arises here is a question of measurement innovation’s effect on the financial performance of company or selection between two or more possible variants of innovation’s realization. Various authors which are focused on innovations processes are divided into two groups in their attitudes towards the question of influence of innovations on financial performance of companies. One group of the authors present the idea that any reliable measurement is not possible or efficient. The second group of authors present some methods theoretically applicable on this measurement but they base their approaches mostly on the methods of measurement of investments effectiveness or they suggest employment of indicators or ratios which wouldn’t be clearly connected with the outcome of innovation process. The aim of submitted article is to compare different approaches to evaluation of the innovation processes. The authors compare various approaches here and by use of analysis and synthesis, they determine their own method how to measure outcome of innovation process.

  12. Coupled hydrological and biogeochemical processes controlling variability of nitrogen species in streamflow during autumn in an upland forest

    Science.gov (United States)

    Sebestyen, Stephen D.; Shanley, James B.; Boyer, Elizabeth W.; Kendall, Carol; Doctor, Daniel H.

    2014-01-01

    Autumn is a season of dynamic change in forest streams of the northeastern United States due to effects of leaf fall on both hydrology and biogeochemistry. Few studies have explored how interactions of biogeochemical transformations, various nitrogen sources, and catchment flow paths affect stream nitrogen variation during autumn. To provide more information on this critical period, we studied (1) the timing, duration, and magnitude of changes to stream nitrate, dissolved organic nitrogen (DON), and ammonium concentrations; (2) changes in nitrate sources and cycling; and (3) source areas of the landscape that most influence stream nitrogen. We collected samples at higher temporal resolution for a longer duration than typical studies of stream nitrogen during autumn. This sampling scheme encompassed the patterns and extremes that occurred during base flow and stormflow events of autumn. Base flow nitrate concentrations decreased by an order of magnitude from 5.4 to 0.7 µmol L−1 during the week when most leaves fell from deciduous trees. Changes to rates of biogeochemical transformations during autumn base flow explained the low nitrate concentrations; in-stream transformations retained up to 72% of the nitrate that entered a stream reach. A decrease of in-stream nitrification coupled with heterotrophic nitrate cycling were primary factors in the seasonal nitrate decline. The period of low nitrate concentrations ended with a storm event in which stream nitrate concentrations increased by 25-fold. In the ensuing weeks, peak stormflow nitrate concentrations progressively decreased over closely spaced, yet similarly sized events. Most stormflow nitrate originated from nitrification in near-stream areas with occasional, large inputs of unprocessed atmospheric nitrate, which has rarely been reported for nonsnowmelt events. A maximum input of 33% unprocessed atmospheric nitrate to the stream occurred during one event. Large inputs of unprocessed atmospheric nitrate

  13. Seasonal baseline of nutrients and stable isotopes in a saline lake of Argentina: biogeochemical processes and river runoff effects.

    Science.gov (United States)

    Kopprio, Germán A; Kattner, Gerhard; Freije, R Hugo; de Paggi, Susana José; Lara, Rubén J

    2014-05-01

    The seasonal variability of inorganic and organic nutrients and stable isotopes and their relations with plankton and environmental conditions were monitored in Lake Chasicó. Principal component analysis evidenced the strong influence of the river runoff on several biogeochemical variables. Silicate concentrations were controlled by diatom biomass and river discharge. Higher values of nitrate and soluble reactive phosphorus (SRP) indicated agricultural uses in the river basin. Elevated pH values (∼ 9) inhibiting nitrification in the lake explained partially the dominance of ammonium: ∼ 83 % of dissolved inorganic nitrogen (DIN). The low DIN/SRP ratio inferred nitrogen limitation, although the hypotheses of iron and CO2 limitation are relevant in alkaline lakes. Particulate organic matter (POM) and dissolved organic matter (DOM) were mainly of autochthonous origin. The main allochthonous input was imported by the river as POM owning to the arid conditions. Dissolved organic carbon was likely top-down regulated by the bacterioplankton grazer Brachionus plicatilis. The δ(13)C signature was a good indicator of primary production and its values were influenced probably by CO2 limitation. The δ(15)N did not evidence nitrogen fixation and suggested the effects of anthropogenic activities. The preservation of a good water quality in the lake is crucial for resource management.

  14. Reappraisal of soil C storage processes. The controversy on structural diversity of humic substances as biogeochemical driver for soil C fluxes

    Science.gov (United States)

    Almendros, Gonzalo; Gonzalez-Vila, Francisco J.; Gonzalez-Perez, Jose Antonio; Knicker, Heike

    2016-04-01

    The functional relationships between the macromolecular structure of the humic substances (HS) and a series of biogeochemical processes related with the C sequestration performance in soils have been recently questioned. In this communication we collect recent data from a wide array of different ecosystems where the C storage in soils has been studied and explained as a possible cause-to-effect relationship or has been found significantly correlated (multivariate statistical models) with a series of structural characteristics of humic materials. The study of humic materials has methodological analytical limitations that are derived from its complex, chaotic and not completely understood structure, that reflects its manifold precursors as well as the local impact of environmental/depositional factors. In this work we attempt to design an exploratory, multiomic approach based on the information provided by the molecular characterization of the soil organic matter (SOM). Massive data harvesting was carried out of statistical variables, to infer biogeochemical proxies (spectroscopic, chromatographic, mass spectrometric quantitative descriptors). The experimental data were acquired from advanced instrumental methodologies, viz, analytical pyrolysis, compound-specific stable isotope analysis (CSIA), derivative infrared (FTIR) spectroscopy, solid-state C-13 and N-15 nuclear magnetic resonance (NMR) and mass spectrometry (MS) data after direct injection (thermoevaporation), previous pyrolysis, or ion averaging of specific m/z ranges from classical GC/MS chromatograms. In the transversal exploratory analysis of the multianalytical information, the data were coded for on-line processing in a stage in which there is no need for interpretation, in molecular or structural terms, of the quantitative data consisting of e.g., peak intensities, signal areas, chromatographic (GC) total abundances, etc. A series of forecasting chemometric approaches (aiming to express SOM

  15. Using complex resistivity imaging to infer biogeochemical processes associated with bioremediation of a uranium-contaminated aquifer

    Energy Technology Data Exchange (ETDEWEB)

    Orozco, A. Flores; Williams, K.H.; Long, P.E.; Hubbard, S.S.; Kemna, A.

    2011-04-01

    Experiments at the Department of Energy's Rifle Integrated Field Research Challenge (IFRC) site near Rifle, Colorado (USA) have demonstrated the ability to remove uranium from groundwater by stimulating the growth and activity of Geobacter species through acetate amendment. Prolonging the activity of these strains in order to optimize uranium bioremediation has prompted the development of minimally-invasive and spatially-extensive monitoring methods diagnostic of their in situ activity and the end products of their metabolism. Here we demonstrate the use of complex resistivity imaging for monitoring biogeochemical changes accompanying stimulation of indigenous aquifer microorganisms during and after a prolonged period (100+ days) of acetate injection. A thorough raw-data statistical analysis of discrepancies between normal and reciprocal measurements and incorporation of a new power-law phase-error model in the inversion were used to significantly improve the quality of the resistivity phase images over those obtained during previous monitoring experiments at the Rifle IRFC site. The imaging results reveal spatiotemporal changes in the phase response of aquifer sediments, which correlate with increases in Fe(II) and precipitation of metal sulfides (e.g., FeS) following the iterative stimulation of iron and sulfate reducing microorganism. Only modest changes in resistivity magnitude were observed over the monitoring period. The largest phase anomalies (>40 mrad) were observed hundreds of days after halting acetate injection, in conjunction with accumulation of Fe(II) in the presence of residual FeS minerals, reflecting preservation of geochemically reduced conditions in the aquifer - a prerequisite for ensuring the long-term stability of immobilized, redox-sensitive contaminants, such as uranium.

  16. Biogeochemical validation of an interannual simulation of the ROMS-PISCES coupled model in the Southeast Pacific

    Directory of Open Access Journals (Sweden)

    Dante Espinoza-Morriberon

    2016-08-01

    Full Text Available Currently biogeochemical models are used to understand and quantify key biogeochemical processes in the ocean. The objective of the present study was to validate predictive ability of a regional configuration of the PISCES biogeochemical model on main biogeochemical variables in Humboldt Current Large Marine Ecosystem (HCLME. The statistical indicators used to evaluate the model were the bias, root-mean-square error, correlation coefficient and, graphically, the Taylor’s diagram. The results showed that the model reproduces the dynamics of the main biogeochemical variables (chlorophyll, dissolved oxygen and nutrients; in particular, the impact of El Niño 1997-1998 in the chlorophyll (decrease and oxygen minimum zone depth (increase. However, it is necessary to carry out sensitivity studies of the PISCES model with different key parameters values to obtain a more accurate representation of the properties of the Ocean.

  17. Modelling biogeochemical processes in sediments from the north-western Adriatic Sea: response to enhanced particulate organic carbon fluxes

    Science.gov (United States)

    Brigolin, Daniele; Rabouille, Christophe; Bombled, Bruno; Colla, Silvia; Vizzini, Salvatrice; Pastres, Roberto; Pranovi, Fabio

    2018-03-01

    This work presents the result of a study carried out in the north-western Adriatic Sea, by combining two different types of biogeochemical models with field sampling efforts. A longline mussel farm was taken as a local source of perturbation to the natural particulate organic carbon (POC) downward flux. This flux was first quantified by means of a pelagic model of POC deposition coupled to sediment trap data, and its effects on sediment bioirrigation capacity and organic matter (OM) degradation pathways were investigated constraining an early diagenesis model by using original data collected in sediment porewater. The measurements were performed at stations located inside and outside the area affected by mussel farm deposition. Model-predicted POC fluxes showed marked spatial and temporal variability, which was mostly associated with the dynamics of the farming cycle. Sediment trap data at the two sampled stations (inside and outside of the mussel farm) showed average POC background flux of 20.0-24.2 mmol C m-2 d-1. The difference of organic carbon (OC) fluxes between the two stations was in agreement with model results, ranging between 3.3 and 14.2 mmol C m-2 d-1, and was primarily associated with mussel physiological conditions. Although restricted, these changes in POC fluxes induced visible effects on sediment biogeochemistry. Observed oxygen microprofiles presented a 50 % decrease in oxygen penetration depth (from 2.3 to 1.4 mm), accompanied by an increase in the O2 influx at the station below the mussel farm (19-31 versus 10-12 mmol O2 m-2 d-1) characterised by higher POC flux. Dissolved inorganic carbon (DIC) and NH4+ concentrations showed similar behaviour, with a more evident effect of bioirrigation underneath the farm. This was confirmed through constraining the early diagenesis model, of which calibration leads to an estimation of enhanced and shallower bioirrigation underneath the farm: bioirrigation rates of 40 yr-1 and irrigation depth of 15 cm were

  18. Integrated water system simulation by considering hydrological and biogeochemical processes: model development, with parameter sensitivity and autocalibration

    Science.gov (United States)

    Zhang, Y. Y.; Shao, Q. X.; Ye, A. Z.; Xing, H. T.; Xia, J.

    2016-02-01

    Integrated water system modeling is a feasible approach to understanding severe water crises in the world and promoting the implementation of integrated river basin management. In this study, a classic hydrological model (the time variant gain model: TVGM) was extended to an integrated water system model by coupling multiple water-related processes in hydrology, biogeochemistry, water quality, and ecology, and considering the interference of human activities. A parameter analysis tool, which included sensitivity analysis, autocalibration and model performance evaluation, was developed to improve modeling efficiency. To demonstrate the model performances, the Shaying River catchment, which is the largest highly regulated and heavily polluted tributary of the Huai River basin in China, was selected as the case study area. The model performances were evaluated on the key water-related components including runoff, water quality, diffuse pollution load (or nonpoint sources) and crop yield. Results showed that our proposed model simulated most components reasonably well. The simulated daily runoff at most regulated and less-regulated stations matched well with the observations. The average correlation coefficient and Nash-Sutcliffe efficiency were 0.85 and 0.70, respectively. Both the simulated low and high flows at most stations were improved when the dam regulation was considered. The daily ammonium-nitrogen (NH4-N) concentration was also well captured with the average correlation coefficient of 0.67. Furthermore, the diffuse source load of NH4-N and the corn yield were reasonably simulated at the administrative region scale. This integrated water system model is expected to improve the simulation performances with extension to more model functionalities, and to provide a scientific basis for the implementation in integrated river basin managements.

  19. Impact of urban effluents on summer hypoxia in the highly turbid Gironde Estuary, applying a 3D model coupling hydrodynamics, sediment transport and biogeochemical processes

    Science.gov (United States)

    Lajaunie-Salla, Katixa; Wild-Allen, Karen; Sottolichio, Aldo; Thouvenin, Bénédicte; Litrico, Xavier; Abril, Gwenaël

    2017-10-01

    Estuaries are increasingly degraded due to coastal urban development and are prone to hypoxia problems. The macro-tidal Gironde Estuary is characterized by a highly concentrated turbidity maximum zone (TMZ). Field observations show that hypoxia occurs in summer in the TMZ at low river flow and a few days after the spring tide peak. In situ data highlight lower dissolved oxygen (DO) concentrations around the city of Bordeaux, located in the upper estuary. Interactions between multiple factors limit the understanding of the processes controlling the dynamics of hypoxia. A 3D biogeochemical model was developed, coupled with hydrodynamics and a sediment transport model, to assess the contribution of the TMZ and the impact of urban effluents through wastewater treatment plants (WWTPs) and sewage overflows (SOs) on hypoxia. Our model describes the transport of solutes and suspended material and the biogeochemical mechanisms impacting oxygen: primary production, degradation of all organic matter (i.e. including phytoplankton respiration, degradation of river and urban watershed matter), nitrification and gas exchange. The composition and the degradation rates of each variable were characterized by in situ measurements and experimental data from the study area. The DO model was validated against observations in Bordeaux City. The simulated DO concentrations show good agreement with field observations and satisfactorily reproduce the seasonal and neap-spring time scale variations around the city of Bordeaux. Simulations show a spatial and temporal correlation between the formation of summer hypoxia and the location of the TMZ, with minimum DO centered in the vicinity of Bordeaux. To understand the contribution of the urban watershed forcing, different simulations with the presence or absence of urban effluents were compared. Our results show that in summer, a reduction of POC from SO would increase the DO minimum in the vicinity of Bordeaux by 3% of saturation. Omitting

  20. Modelling biogeochemical processes in sediments from the north-western Adriatic Sea: response to enhanced particulate organic carbon fluxes

    Directory of Open Access Journals (Sweden)

    D. Brigolin

    2018-03-01

    Full Text Available This work presents the result of a study carried out in the north-western Adriatic Sea, by combining two different types of biogeochemical models with field sampling efforts. A longline mussel farm was taken as a local source of perturbation to the natural particulate organic carbon (POC downward flux. This flux was first quantified by means of a pelagic model of POC deposition coupled to sediment trap data, and its effects on sediment bioirrigation capacity and organic matter (OM degradation pathways were investigated constraining an early diagenesis model by using original data collected in sediment porewater. The measurements were performed at stations located inside and outside the area affected by mussel farm deposition. Model-predicted POC fluxes showed marked spatial and temporal variability, which was mostly associated with the dynamics of the farming cycle. Sediment trap data at the two sampled stations (inside and outside of the mussel farm showed average POC background flux of 20.0–24.2 mmol C m−2 d−1. The difference of organic carbon (OC fluxes between the two stations was in agreement with model results, ranging between 3.3 and 14.2 mmol C m−2 d−1, and was primarily associated with mussel physiological conditions. Although restricted, these changes in POC fluxes induced visible effects on sediment biogeochemistry. Observed oxygen microprofiles presented a 50 % decrease in oxygen penetration depth (from 2.3 to 1.4 mm, accompanied by an increase in the O2 influx at the station below the mussel farm (19–31 versus 10–12 mmol O2 m−2 d−1 characterised by higher POC flux. Dissolved inorganic carbon (DIC and NH4+ concentrations showed similar behaviour, with a more evident effect of bioirrigation underneath the farm. This was confirmed through constraining the early diagenesis model, of which calibration leads to an estimation of enhanced and shallower bioirrigation underneath the farm

  1. Evaluation of steelmaking processes

    Energy Technology Data Exchange (ETDEWEB)

    Fruehan, R.J. [Carnegie-Mellon Univ., Pittsburgh, PA (United States)

    1994-01-01

    Objective of the AISI Direct Steelmaking Program is to develop a process for producing steel directly from ore and coal; the process should be less capital intensive, consume less energy, and have higher productivity. A task force was formed to examine available processes: trough, posthearth, IRSID, Electric Arc Furnace, energy optimizing furnace. It is concluded that there is insufficient incentive to replace a working BOF with any of these processes to refine hot metal; however, if new steelmaking capacity is required, IRSID and EOF should be considered. A fully continuous process should not be considered until direct ironmaking and continuous refining are perfected.

  2. Incorporating nitrogen fixing cyanobacteria in the global biogeochemical model HAMOCC

    Science.gov (United States)

    Paulsen, Hanna; Ilyina, Tatiana; Six, Katharina

    2015-04-01

    Nitrogen fixation by marine diazotrophs plays a fundamental role in the oceanic nitrogen and carbon cycle as it provides a major source of 'new' nitrogen to the euphotic zone that supports biological carbon export and sequestration. Since most global biogeochemical models include nitrogen fixation only diagnostically, they are not able to capture its spatial pattern sufficiently. Here we present the incorporation of an explicit, dynamic representation of diazotrophic cyanobacteria and the corresponding nitrogen fixation in the global ocean biogeochemical model HAMOCC (Hamburg Ocean Carbon Cycle model), which is part of the Max Planck Institute for Meteorology Earth system model (MPI-ESM). The parameterization of the diazotrophic growth is thereby based on available knowledge about the cyanobacterium Trichodesmium spp., which is considered as the most significant pelagic nitrogen fixer. Evaluation against observations shows that the model successfully reproduces the main spatial distribution of cyanobacteria and nitrogen fixation, covering large parts of the tropical and subtropical oceans. Besides the role of cyanobacteria in marine biogeochemical cycles, their capacity to form extensive surface blooms induces a number of bio-physical feedback mechanisms in the Earth system. The processes driving these interactions, which are related to the alteration of heat absorption, surface albedo and momentum input by wind, are incorporated in the biogeochemical and physical model of the MPI-ESM in order to investigate their impacts on a global scale. First preliminary results will be shown.

  3. Linking the Modern and Recent Record of Cabo Frio Upwelling with Local Climate and Biogeochemical Processes in Hypersaline Coastal Lagoons, Região dos Lagos, Rio de Janeiro, Brazil

    Science.gov (United States)

    McKenzie, J. A.; Nascimento, G. S.; Albuquerque, A. L.; Belem, A. L.; Carreira, R.; Eglinton, T. I.; Vasconcelos, C.

    2015-12-01

    A unique marine and lagoonal system along the coast east of Rio de Janeiro is being investigated to understand the impact of climatic variability on the South Atlantic carbon cycle and biomineralisation processes involved in carbonate precipitation in the hypersaline coastal lagoons. The region is dominated by a semi-arid microclimate attributed to the local coastal upwelling phenomenon near Cabo Frio. The intensity of the upwelling affects the hydrology of the annual water and biogeochemical cycles in the lagoons, as well as biogeochemical signals of environmental change recorded in both onshore and offshore sediments. Preliminary results of δ18O and δD values of water samples collected monthly in Lagoa Vermelha and Brejo do Espinho from 2011 to 2014 show lower values for waters corresponding to the wet season, reflecting increased input of meteoric water. The higher values for waters collected during the dry season reflect the greater amount of evaporation with increased seasonal aridity. Radiocarbon dating of Holocene marine and lagoonal cores indicates that Mg-carbonate precipitation in the lagoons is associated with high evaporation. Modern field observations for the last 3 years suggest that the amount of carbonate precipitation is correlated with evaporitic conditions associated with the upwelling phenomenon. A calibration study of hydrogen isotopic fractionation in the modern lagoons is underway to define a relationship between δDlipid of suspended particles and δDwater of associated water. This isotopic relationship will be applied to material obtained in cores from the lagoons. Offshore cores will be studied using well-tested paleotemperature proxies to evaluate the intensity of the upwelling during the Holocene. In summary, linking the coastal upwelling with the lagoonal hydrology has the potential to furnish important insights about the relationship between the local climate and paleoceanographic circulation associated with the regional carbon cycle.

  4. Spatial Patterns in Biogeochemical Processes During Peak Growing Season in Oiled and Unoiled Louisiana Salt Marshes: A Multi-Year Analysis

    Science.gov (United States)

    Chelsky, A.; Marton, J. M.; Bernhard, A. E.; Giblin, A. E.; Setta, S. P.; Hill, T. D.; Roberts, B. J.

    2016-02-01

    Louisiana salt marshes are important sites for carbon and nitrogen cycling because they can mitigate fluxes of nutrients and carbon to the Gulf of Mexico where a large hypoxic zone develops annually. The aim of this study was to investigate spatial and temporal patterns of biogeochemical processes in Louisiana coastal wetlands during peak growing season, and to investigate whether the Deepwater Horizon oil spill resulted in persistent changes to these rates. We measured nitrification potential and sediment characteristics at two pairs of oiled/unoiled marshes in three regions across the Louisiana coast (Terrebonne and east and west Barataria Bay) in July from 2012 to 2015, with plots along a gradient from the salt marsh edge to the interior. Rates of nitrification potential across the coast (overall mean of 901 ± 115 nmol gdw-1 d-1 from 2012-2014) were high compared to other published rates for salt marshes but displayed high variability at the plot level (4 orders of magnitude). Within each region interannual means varied by factors of 2-5. Nitrification potential did not differ with oiling history, but did display consistent spatial patterns within each region that corresponded to changes in relative elevation and inundation, which influence patterns of soil properties and microbial communities. In 2015, we also measured greenhouse gas (CO2, N2O and CH4) production and denitrification enzyme activity rates in addition to nitrification potential across the region to investigate spatial relationships between these processes.

  5. A reactive transport modeling approach to simulate biogeochemical processes in pore structures with pore-scale heterogeneities

    NARCIS (Netherlands)

    Gharasoo, M.G.; Centler, F.; Regnier, P.; Harms, H.; Thullner, M.

    2012-01-01

    Redox processes, including degradation of organic contaminants, are often controlled by microorganisms residing in natural porous media like soils or aquifers. These environments are characterized by heterogeneities at various scales which influence the transport of chemical species and the spatial

  6. Wastewater engineering applications of BioIronTech process based on the biogeochemical cycle of iron bioreduction and (biooxidation

    Directory of Open Access Journals (Sweden)

    Volodymyr Ivanov

    2014-12-01

    Full Text Available Bioreduction of Fe(III and biooxidation of Fe(II can be used in wastewater engineering as an innovative biotechnology BioIronTech, which is protected for commercial applications by US patent 7393452 and Singapore patent 106658 “Compositions and methods for the treatment of wastewater and other waste”. The BioIronTech process comprises the following steps: 1 anoxic bacterial reduction of Fe(III, for example in iron ore powder; 2 surface renovation of iron ore particles due to the formation of dissolved Fe2+ ions; 3 precipitation of insoluble ferrous salts of inorganic anions (phosphate or organic anions (phenols and organic acids; 4 (biooxidation of ferrous compunds with the formation of negatively, positively, or neutrally charged ferric hydroxides, which are good adsorbents of many pollutants; 5 disposal or thermal regeration of ferric (hydroxide. Different organic substances can be used as electron donors in bioreduction of Fe(III. Ferrous ions and fresh ferrous or ferric hydroxides that are produced after iron bioreduction and (biooxidation adsorb and precipitate diferent negatively charged molecules, for example chlorinated compounds of sucralose production wastewater or other halogenated organics, as well as phenols, organic acids, phosphate, and sulphide. Reject water (return liquor from the stage of sewage sludge dewatering on municipal wastewater treatment plants represents from 10 to 50% of phosphorus load when being recycled to the aeration tank. BioIronTech process can remove/recover more than 90% of phosphorous from this reject water thus replacing the conventional process of phosphate precipitation by ferric/ferrous salts, which are 20–100 times more expensive than iron ore, which is used in BioIronTech process. BioIronTech process can remarkably improve the aerobic and anaerobic treatments of municipal and industrial wastewaters, especially anaerobic digestion of lipid- and sulphate-containing food-processing wastewater. It

  7. Estimating the potential of energy saving and carbon emission mitigation of cassava-based fuel ethanol using life cycle assessment coupled with a biogeochemical process model

    Science.gov (United States)

    Jiang, Dong; Hao, Mengmeng; Fu, Jingying; Tian, Guangjin; Ding, Fangyu

    2017-09-01

    Global warming and increasing concentration of atmospheric greenhouse gas (GHG) have prompted considerable interest in the potential role of energy plant biomass. Cassava-based fuel ethanol is one of the most important bioenergy and has attracted much attention in both developed and developing countries. However, the development of cassava-based fuel ethanol is still faced with many uncertainties, including raw material supply, net energy potential, and carbon emission mitigation potential. Thus, an accurate estimation of these issues is urgently needed. This study provides an approach to estimate energy saving and carbon emission mitigation potentials of cassava-based fuel ethanol through LCA (life cycle assessment) coupled with a biogeochemical process model—GEPIC (GIS-based environmental policy integrated climate) model. The results indicate that the total potential of cassava yield on marginal land in China is 52.51 million t; the energy ratio value varies from 0.07 to 1.44, and the net energy surplus of cassava-based fuel ethanol in China is 92,920.58 million MJ. The total carbon emission mitigation from cassava-based fuel ethanol in China is 4593.89 million kgC. Guangxi, Guangdong, and Fujian are identified as target regions for large-scale development of cassava-based fuel ethanol industry. These results can provide an operational approach and fundamental data for scientific research and energy planning.

  8. Estimating the potential of energy saving and carbon emission mitigation of cassava-based fuel ethanol using life cycle assessment coupled with a biogeochemical process model.

    Science.gov (United States)

    Jiang, Dong; Hao, Mengmeng; Fu, Jingying; Tian, Guangjin; Ding, Fangyu

    2017-09-14

    Global warming and increasing concentration of atmospheric greenhouse gas (GHG) have prompted considerable interest in the potential role of energy plant biomass. Cassava-based fuel ethanol is one of the most important bioenergy and has attracted much attention in both developed and developing countries. However, the development of cassava-based fuel ethanol is still faced with many uncertainties, including raw material supply, net energy potential, and carbon emission mitigation potential. Thus, an accurate estimation of these issues is urgently needed. This study provides an approach to estimate energy saving and carbon emission mitigation potentials of cassava-based fuel ethanol through LCA (life cycle assessment) coupled with a biogeochemical process model-GEPIC (GIS-based environmental policy integrated climate) model. The results indicate that the total potential of cassava yield on marginal land in China is 52.51 million t; the energy ratio value varies from 0.07 to 1.44, and the net energy surplus of cassava-based fuel ethanol in China is 92,920.58 million MJ. The total carbon emission mitigation from cassava-based fuel ethanol in China is 4593.89 million kgC. Guangxi, Guangdong, and Fujian are identified as target regions for large-scale development of cassava-based fuel ethanol industry. These results can provide an operational approach and fundamental data for scientific research and energy planning.

  9. Carbon, oxygen and strontium isotopic constraints on fluid sources, temperatures and biogeochemical processes during the formation of seep carbonates - Secchia River site, Northern Apennines

    Science.gov (United States)

    Viola, Irene; Capozzi, Rossella; Bernasconi, Stefano M.; Rickli, Jörg

    2017-07-01

    and fluid supply from a well-defined hydrocarbon field. The seep carbonate characteristics have enlightened variations in biogeochemical processes, which can be rarely quantified in ancient and present-day marine environments.

  10. Biogeochemical processes controlling the mobility of major ions and trace metals in aquitard sediments beneath an oil sand tailing pond: Laboratory studies and reactive transport modeling

    Science.gov (United States)

    Holden, A. A.; Haque, S. E.; Mayer, K. U.; Ulrich, A. C.

    2013-08-01

    Increased production and expansion of the oil sand industry in Alberta are of great benefit to the economy, but they carry major environmental challenges. The volume of fluid fine tailings requiring storage is 840 × 106 m3 and growing, making it imperative that we better understand the fate and transport of oil sand process-affected water (OSPW) seepage from these facilities. Accordingly, the current study seeks to characterize both a) the potential for major ion and trace element release, and b) the principal biogeochemical processes involved, as tailing pond OSPW infiltrates into, and interacts with, underlying glacial till sediments prior to reaching down gradient aquifers or surface waters. Objectives were addressed through a series of aqueous and solid phase experiments, including radial diffusion cells, an isotope analysis, X-ray diffraction, and sequential extractions. The diffusion cells were also simulated in a reactive transport framework to elucidate key reaction processes. The experiments indicate that the ingress and interaction of OSPW with the glacial till sediment-pore water system will result in: a mitigation of ingressing Na (retardation), displacement and then limited precipitation of exchangeable Ca and Mg (as carbonates), sulfate reduction and subsequent precipitation of the produced sulfides, as well as biodegradation of organic carbon. High concentrations of ingressing Cl (~ 375 mg L- 1) and Na (~ 575 mg L- 1) (even though the latter is delayed, or retarded) are expected to migrate through the till and into the underlying sand channel. Trace element mobility was influenced by ion exchange, oxidation-reduction, and mineral phase reactions including reductive dissolution of metal oxyhydroxides — in accordance with previous observations within sandy aquifer settings. Furthermore, although several trace elements showed the potential for release (Al, B, Ba, Cd, Mn, Pb, Si, Sr), large-scale mobilization is not supported. Thus, the present

  11. Influence of water column dynamics on sulfide oxidation and other major biogeochemical processes in the chemocline of Mariager Fjord (Denmark)

    DEFF Research Database (Denmark)

    Zopfi, J.; Ferdelman, TG; Jørgensen, BB

    2001-01-01

    steady-stare conditions, the upward fluxes of reductants and downward fluxes of oxidants in the water column were balanced. However, changes in the hydrographical conditions caused a transient nonsteady-state at the chemocline and had a great impact on process rates and the distribution of chemical...... a high formation rare and (b) was only transient, caused by chemocline perturbations. Kinetic calculations of chemical sulfide oxidation based on actual conditions in the chemocline revealed that under steady-state conditions with a narrow chemocline and low reactant concentrations, biological sulfide...... oxidation may account for more than 88% of the total sulfide oxidation. Under nonsteady-state conditions, where oxic and sulfidic water masses were recently mixed, resulting in an expanded chemocline, the proportion of chemical sulfide oxidation increased. The sulfide oxidation rate determined by incubation...

  12. Disturbance decouples biogeochemical cycles across forests of the southeastern US

    Science.gov (United States)

    Ashley D. Keiser; Jennifer D. Knoepp; Mark A. Bradford

    2016-01-01

    Biogeochemical cycles are inherently linked through the stoichiometric demands of the organisms that cycle the elements. Landscape disturbance can alter element availability and thus the rates of biogeochemical cycling. Nitrification is a fundamental biogeochemical process positively related to plant productivity and nitrogen loss from soils to aquatic systems, and the...

  13. Genome-Enabled Modeling of Biogeochemical Processes Predicts Metabolic Dependencies that Connect the Relative Fitness of Microbial Functional Guilds

    Science.gov (United States)

    Brodie, E.; King, E.; Molins, S.; Karaoz, U.; Steefel, C. I.; Banfield, J. F.; Beller, H. R.; Anantharaman, K.; Ligocki, T. J.; Trebotich, D.

    2015-12-01

    Pore-scale processes mediated by microorganisms underlie a range of critical ecosystem services, regulating carbon stability, nutrient flux, and the purification of water. Advances in cultivation-independent approaches now provide us with the ability to reconstruct thousands of genomes from microbial populations from which functional roles may be assigned. With this capability to reveal microbial metabolic potential, the next step is to put these microbes back where they belong to interact with their natural environment, i.e. the pore scale. At this scale, microorganisms communicate, cooperate and compete across their fitness landscapes with communities emerging that feedback on the physical and chemical properties of their environment, ultimately altering the fitness landscape and selecting for new microbial communities with new properties and so on. We have developed a trait-based model of microbial activity that simulates coupled functional guilds that are parameterized with unique combinations of traits that govern fitness under dynamic conditions. Using a reactive transport framework, we simulate the thermodynamics of coupled electron donor-acceptor reactions to predict energy available for cellular maintenance, respiration, biomass development, and enzyme production. From metagenomics, we directly estimate some trait values related to growth and identify the linkage of key traits associated with respiration and fermentation, macromolecule depolymerizing enzymes, and other key functions such as nitrogen fixation. Our simulations were carried out to explore abiotic controls on community emergence such as seasonally fluctuating water table regimes across floodplain organic matter hotspots. Simulations and metagenomic/metatranscriptomic observations highlighted the many dependencies connecting the relative fitness of functional guilds and the importance of chemolithoautotrophic lifestyles. Using an X-Ray microCT-derived soil microaggregate physical model combined

  14. DayCent-Chem Simulations of Ecological and Biogeochemical Processes of Eight Mountain Ecosystems in the United States

    Science.gov (United States)

    Hartman, Melannie D.; Baron, Jill S.; Clow, David W.; Creed, Irena F.; Driscoll, Charles T.; Ewing, Holly A.; Haines, Bruce D.; Knoepp, Jennifer; Lajtha, Kate; Ojima, Dennis S.; Parton, William J.; Renfro, Jim; Robinson, R. Bruce; Van Miegroet, Helga; Weathers, Kathleen C.; Williams, Mark W.

    2009-01-01

    deposition as a result of dry and fog inputs. The uncertainties related to weathering reactions, deposition, soil cation exchange capacity, and groundwater contributions influenced how well the simulated acid neutralizing capacity (ANC) and pH estimates compared to observed values. Daily discharge was well represented by the model for most sites. The chapters of this report describe the parameterization for each site and summarize model results for ecosystem variables, stream discharge, and stream chemistry. This intersite comparison exercise provided insight about important and possibly not well understood processes.

  15. Spatio-temporal dynamics of biogeochemical processes and air-sea CO2 fluxes in the Western English Channel based on two years of FerryBox deployment

    Science.gov (United States)

    Marrec, P.; Cariou, T.; Latimier, M.; Macé, E.; Morin, P.; Vernet, M.; Bozec, Y.

    2014-12-01

    From January 2011 to January 2013, a FerryBox system was installed on a Voluntary Observing Ship (VOS), which crossed the Western English Channel (WEC) between Roscoff (France) and Plymouth (UK) up to 3 times a day. The FerryBox continuously measured sea surface temperature (SST), sea surface salinity (SSS), dissolved oxygen (DO), fluorescence and partial pressure of CO2 (from April 2012) along the ferry track. Sensors were calibrated based on 714 bimonthly surface samplings with precisions of 0.016 for SSS, 3.3 μM for DO, 0.40 μg L- 1 for Chlorophyll-a (Chl-a) (based on fluorescence measurements) and 5.2 μatm for pCO2. Over the 2 years of deployment (900 crossings), we reported 9% of data lost due to technical issues and quality checked data was obtained to allow investigation of the dynamics of biogeochemical processes related to air-sea CO2 fluxes in the WEC. Based on this unprecedented high-frequency dataset, the physical structure of the WEC was assessed using SST anomalies and the presence of a thermal front was observed around the latitude 49.5°N, which divided the WEC in two main provinces: the seasonally stratified northern WEC (nWEC) and the all-year well-mixed southern WEC (sWEC). These hydrographical properties strongly influenced the spatial and inter-annual distributions of phytoplankton blooms, which were mainly limited by nutrients and light availability in the nWEC and the sWEC, respectively. Air-sea CO2 fluxes were also highly related to hydrographical properties of the WEC between late April and early September 2012, with the sWEC a weak source of CO2 to the atmosphere of 0.9 mmol m- 2 d- 1, whereas the nWEC acted as a sink for atmospheric CO2 of 6.9 mmol m- 2 d- 1. The study of short time-scale dynamics of air-sea CO2 fluxes revealed that an intense and short (less than 10 days) summer bloom in the nWEC contributed to 29% of the CO2 sink during the productive period, highlighting the necessity for high frequency observations in coastal

  16. Biogeochemical processes controlling the mobility of major ions and trace metals in aquitard sediments beneath an oil sand tailing pond: laboratory studies and reactive transport modeling.

    Science.gov (United States)

    Holden, A A; Haque, S E; Mayer, K U; Ulrich, A C

    2013-08-01

    Increased production and expansion of the oil sand industry in Alberta are of great benefit to the economy, but they carry major environmental challenges. The volume of fluid fine tailings requiring storage is 840×10(6) m(3) and growing, making it imperative that we better understand the fate and transport of oil sand process-affected water (OSPW) seepage from these facilities. Accordingly, the current study seeks to characterize both a) the potential for major ion and trace element release, and b) the principal biogeochemical processes involved, as tailing pond OSPW infiltrates into, and interacts with, underlying glacial till sediments prior to reaching down gradient aquifers or surface waters. Objectives were addressed through a series of aqueous and solid phase experiments, including radial diffusion cells, an isotope analysis, X-ray diffraction, and sequential extractions. The diffusion cells were also simulated in a reactive transport framework to elucidate key reaction processes. The experiments indicate that the ingress and interaction of OSPW with the glacial till sediment-pore water system will result in: a mitigation of ingressing Na (retardation), displacement and then limited precipitation of exchangeable Ca and Mg (as carbonates), sulfate reduction and subsequent precipitation of the produced sulfides, as well as biodegradation of organic carbon. High concentrations of ingressing Cl (~375 mg L(-1)) and Na (~575 mg L(-1)) (even though the latter is delayed, or retarded) are expected to migrate through the till and into the underlying sand channel. Trace element mobility was influenced by ion exchange, oxidation-reduction, and mineral phase reactions including reductive dissolution of metal oxyhydroxides - in accordance with previous observations within sandy aquifer settings. Furthermore, although several trace elements showed the potential for release (Al, B, Ba, Cd, Mn, Pb, Si, Sr), large-scale mobilization is not supported. Thus, the present

  17. On the coupling of benthic and pelagic biogeochemical models

    NARCIS (Netherlands)

    Soetaert, K.E.R.; Middelburg, J.J.; Herman, P.M.J.; Buis, K.

    2000-01-01

    Mutual interaction of water column and sediment processes is either neglected or only crudely approximated in many biogeochemical models. We have reviewed the approaches to couple benthic and pelagic biogeochemical models. It is concluded that they can be classified into a hierarchical set

  18. Biogeochemical speciation of Fe in ocean water

    NARCIS (Netherlands)

    Hiemstra, T.; Riemsdijk, van W.H.

    2006-01-01

    The biogeochemical speciation of Fe in seawater has been evaluated using the consistent Non-Ideal Competitive Adsorption model (NICA¿Donnan model). Two types of data sets were used, i.e. Fe-hydroxide solubility data and competitive ligand equilibration/cathodic stripping voltammetry (CLE/CSV) Fe

  19. Characterization of the Oriskany and Berea Sandstones: Evaluating Biogeochemical Reactions of Potential Sandstone–Hydraulic Fracturing Fluid Interaction

    Energy Technology Data Exchange (ETDEWEB)

    Verba, Circe [National Energy Technology Lab. (NETL), Albany, OR (United States); Harris, Aubrey [National Energy Technology Lab. (NETL), Albany, OR (United States)

    2016-07-07

    The Marcellus shale, located in the mid-Atlantic Appalachian Basin, has been identified as a source for natural gas and targeted for hydraulic fracturing recovery methods. Hydraulic fracturing is a technique used by the oil and gas industry to access petroleum reserves in geologic formations that cannot be accessed with conventional drilling techniques (Capo et al., 2014). This unconventional technique fractures rock formations that have low permeability by pumping pressurized hydraulic fracturing fluids into the subsurface. Although the major components of hydraulic fracturing fluid are water and sand, chemicals, such as recalcitrant biocides and polyacrylamide, are also used (Frac Focus, 2015). There is domestic concern that the chemicals could reach groundwater or surface water during transport, storage, or the fracturing process (Chapman et al., 2012). In the event of a surface spill, understanding the natural attenuation of the chemicals in hydraulic fracturing fluid, as well as the physical and chemical properties of the aquifers surrounding the spill site, will help mitigate potential dangers to drinking water. However, reports on the degradation pathways of these chemicals are limited in existing literature. The Appalachian Basin Marcellus shale and its surrounding sandstones host diverse mineralogical suites. During the hydraulic fracturing process, the hydraulic fracturing fluids come into contact with variable mineral compositions. The reactions between the fracturing fluid chemicals and the minerals are very diverse. This report: 1) describes common minerals (e.g. quartz, clay, pyrite, and carbonates) present in the Marcellus shale, as well as the Oriskany and Berea sandstones, which are located stratigraphically below and above the Marcellus shale; 2) summarizes the existing literature of the degradation pathways for common hydraulic fracturing fluid chemicals [polyacrylamide, ethylene glycol, poly(diallyldimethylammonium chloride), glutaraldehyde

  20. Biogeochemical aspects of aquifer thermal energy storage

    NARCIS (Netherlands)

    Brons, H.J.

    1992-01-01

    During the process of aquifer thermal energy storage the in situ temperature of the groundwater- sediment system may fluctuate significantly. As a result the groundwater characteristics can be considerably affected by a variety of chemical, biogeochemical and microbiological

  1. Spectral induced polarization as a tool to map subsurface biogeochemical hot spots: a first laboratory evaluation in the Fe-S system

    Science.gov (United States)

    Nordsiek, Sven; Gilfedder, Ben; Frei, Sven

    2017-04-01

    Zones of intense biogeochemical reactivity (hot spots) arise in the saturated subsurface at the interface between regions with oxidizing and reducing conditions. Hot spots are both sinks and sources of different chemical compounds, thus they are of particular importance for element cycling in the subsurface. However, the investigation of hot spot structures is difficult, because they are not directly identifiable from the surface and can only be investigated by invasive methods in the subsurface. Additionally, they often form in sensitive wetland ecosystems where only non-destructive measurements are applicable to avoid significant degradation of these sensitive environments. Under these circumstances, geophysical methods may provide useful tools to identify biogeochemically active regions. One of the most important biogeochemical reactions in wetlands is the reduction of sulphate and formation and accumulation of FexSy minerals (where x and y delineate mineral stoichiometry). These reactions only occur in specific hot spots where specific chemical and microbial conditions are met. Within a research project concerning biogeochemical transformations and turnover in wetlands, we investigate the applicability of the geoelectrical method of spectral induced polarization (SIP) to locate and monitor regions containing polarizing FexSy particles as indicator for biogeochemical hot spots. After developing and testing a sample holder and a set of non-polarizing electrodes for laboratory SIP measurements, we performed experiments on natural soil samples taken from the hyporheic zone of a local river channel. The collected material originates from a location known for biogeochemical activity. The sample contains a high percentage of dark grayish/black sediment interpreted as FexSy, and possibly pyrite (FeS2). The material was homogenized and split into four samples. The FexSy concentration was adjusted to three different levels by oxidation using H2O2. For all samples we

  2. Dispersal-Based Microbial Community Assembly Decreases Biogeochemical Function

    Energy Technology Data Exchange (ETDEWEB)

    Graham, Emily B.; Stegen, James C.

    2017-11-01

    Much research has focused on improving ecosystem models by incorporating microbial regulation of biogeochemistry. However, models still struggle to predict biogeochemical function in future scenarios linked to accelerating global environmental change. Ecological mechanisms may influence the relationship between microbial communities and biogeochemistry, and here, we show that stochastic dispersal processes (e.g., wind-driven or hydrologic transport) can suppress biogeochemical function. Microbial communities are assembled by deterministic (e.g., selection) and stochastic (e.g., dispersal) processes, and the balance of these two processes is hypothesized to influence how microbial communities correspond to biogeochemical function. We explore the theoretical basis for this hypothesis and use ecological simulation models to demonstrate potential influences of assembly processes on ecosystem function. We assemble ‘receiving’ communities under different levels of dispersal from a source community (selection-only, moderate dispersal, and homogenizing dispersal). We then calculate the degree to which assembled individuals are adapted to their environment and relate the level of adaptation to biogeochemical function. We also use ecological null models to further link assembly the level of deterministic assembly to function. We find that dispersal can decrease biogeochemical function by increasing the proportion of maladapted taxa, outweighing selection. The niche breadth of taxa is also a key determinant of biogeochemical function, suggesting a tradeoff between the function of generalist and specialist species. Together, our results highlight the importance of considering ecological assembly processes to reduce uncertainty in predictions of biogeochemical cycles under future environmental scenarios.

  3. Biogeochemical processes in an urban, restored wetland of San Francisco Bay, California, 2007-2009; methods and data for plant, sediment and water parameters

    Science.gov (United States)

    Windham-Myers, Lisamarie; Marvin-DiPasquale, Mark C.; Agee, Jennifer L.; Kieu, Le H.; Kakouros, Evangelos; Erikson, Li H.; Ward, Kristen

    2010-01-01

    The restoration of 18 acres of historic tidal marsh at Crissy Field has had great success in terms of public outreach and visibility, but less success in terms of revegetated marsh sustainability. Native cordgrass (Spartina foliosa) has experienced dieback and has failed to recolonize following extended flooding events during unintended periodic closures of its inlet channel, which inhibits daily tidal flushing. We examined the biogeochemical impacts of these impoundment events on plant physiology and on sulfur and mercury chemistry to help the National Park Service land managers determine the relative influence of these inlet closures on marsh function. In this comparative study, we examined key pools of sulfur, mercury, and carbon compounds both during and between closure events. Further, we estimated the net hydrodynamic flux of methylmercury and total mercury to and from the marsh during a 24-hour diurnal cycle. This report documents the methods used and the data generated during the study.

  4. 15 CFR 286.7 - Evaluation process.

    Science.gov (United States)

    2010-01-01

    ... 15 Commerce and Foreign Trade 1 2010-01-01 2010-01-01 false Evaluation process. 286.7 Section 286... VOLUNTARY CONFORMITY ASSESSMENT SYSTEM EVALUATION (NVCASE) PROGRAM § 286.7 Evaluation process. (a) Each applicant requesting to be evaluated under NVCASE is expected to initiate the process and assume designated...

  5. Process liability evaluation for EUVL

    Science.gov (United States)

    Aoyama, Hajime; Tawarayama, Kazuo; Tanaka, Yuusuke; Kawamura, Daisuke; Arisawa, Yukiyasu; Uno, Taiga; Kamo, Takashi; Tanaka, Toshihiko; Itani, Toshiro; Tanaka, Hiroyuki; Nakajima, Yumi; Inanami, Ryoichi; Takai, Kosuke; Murano, Koji; Koshiba, Takeshi; Hashimoto, Kohji; Mori, Ichiro

    2009-03-01

    This paper concerns the readiness of extreme ultraviolet lithography (EUVL) for high-volume manufacture based on accelerated development in critical areas and the construction of a process liability (PL) test site that integrates results in these areas. The overall lithography performance was determined from the performance of the exposure tool, the printability obtainable with the resist, mask fabrication with accurate critical dimension (CD) control, and correction technology for mask data preparation. The EUV1 exposure tool can carry out exposure over the full field (26 mm × 33 mm) at a resolution high enough for 32-nm line-and-space patterns when Selete Standard Resist 3 (SSR3) is used. Thus, the test site was designed for the full-field exposure of various pattern sizes [half-pitch (hp) 32-50 nm]. The CD variation of the mask was found to be as good as 2.8 nm (3σ) and only one printable defect was detected. The effect of flare on CD variation is a critical issue in EUVL; so flare was compensated for based on the point spread function for the projection optics of the EUV1 and aerial simulations that took resist blur into account. The accuracy obtained when an electronic design automation (EDA) tool was used for mask resizing was found to be very good (error areas was evaluated by electrical tests on low-resistance tungsten wiring. The yield for the electrically open test for hp 50 nm (32-nm logic node) and hp 40 nm (22-nm logic node) were found to be over 60% and around 50%, respectively; and the yield tended to decrease as patterns became smaller. We found the PL test site to be very useful for determining where further improvements need to be made and for evaluating the production readiness of EUVL.

  6. Using Halogens (Cl, Br, F, I) and Stable Isotopes of Water (δ18O, δ2H) to Trace Hydrological and Biogeochemical Processes in Prairie Wetlands

    Science.gov (United States)

    Levy, Z. F.; Lu, Z.; Mills, C. T.; Goldhaber, M. B.; Rosenberry, D. O.; Mushet, D.; Siegel, D. I.; Fiorentino, A. J., II; Gade, M.; Spradlin, J.

    2014-12-01

    Prairie pothole wetlands are ubiquitous features of the Great Plains of North America, and important habitat for amphibians and migratory birds. The salinity of proximal wetlands varies highly due to groundwater-glacial till interactions, which influence wetland biota and associated ecosystem functions. Here we use halogens and stable isotopes of water to fingerprint hydrological and biogeochemical controls on salt cycling in a prairie wetland complex. We surveyed surface, well, and pore waters from a groundwater recharge wetland (T8) and more saline closed (P1) and open (P8) basin discharge wetlands in the Cottonwood Lake Study Area (ND) in August/October 2013 and May 2014. Halogen concentrations varied over a broad range throughout the study area (Cl = 2.2 to 170 mg/L, Br = 13 to 2000 μg/L, F = evaporation-enriched pond water (δ18O = -9.5 to -2.71 ‰) mixes with shallow groundwater in the top 0.6 m of fringing wetland soils and 1.2 m of the substrate in the center of P1. Our results suggest endogenous sources for Br and I within the prairie landscape that may be controlled by biological mechanisms or weathering of shale from glacial till.

  7. 76 FR 37344 - Technology Evaluation Process

    Science.gov (United States)

    2011-06-27

    ...-NOA-0039] Technology Evaluation Process AGENCY: Office of Energy Efficiency and Renewable Energy... evaluation process. The stakeholder comment period is being extended an additional 30 days to give potential... seeks comments and information related to a commercial buildings technology evaluation process. DOE is...

  8. Evaluation of process inventory uncertainties

    International Nuclear Information System (INIS)

    Roberts, N.J.

    1980-01-01

    This paper discusses the determination of some of the process inventory uncertainties in the Fast Flux Test Facility (FFTF) process line at the Los Alamos Scientific Laboratory (LASL) Plutonium Processing Facility (TA-55). A brief description of the FFTF process is given, along with a more detailed look at the peroxide precipitation and re-dissolution (PR) process. Emphasis is placed on the identification of the product and sidestreams from the unit processes, as they have application to the accountability measurements. The method of measurement of each of the product and sidestreams and their associated uncertainties are discussed. Some typical data for the PR process are presented, along with a discussion of the data. The data presented are based on our operating experience, and data on file in the TA-55 Nuclear Material Accountability System (PF/LASS/

  9. Mercury behaviour and C, N, and P biogeochemical cycles during ecological restoration processes of old mining sites in French Guiana.

    Science.gov (United States)

    Couic, Ewan; Grimaldi, Michel; Alphonse, Vanessa; Balland-Bolou-Bi, Clarisse; Livet, Alexandre; Giusti-Miller, Stéphanie; Sarrazin, Max; Bousserrhine, Noureddine

    2018-04-25

    Several decades of gold mining extraction activities in the Amazonian rainforest have caused deforestation and pollution. While ecological rehabilitation is essential for restoring biodiversity and decreasing erosion on deforested lands, few studies note the behaviour or toxicity of trace elements during the rehabilitation process. Our original study focused on the potential use of microbial activity and Hg speciation and compared them with As, Cu, Zn and Cr speciation in assessing the chemical and biological quality of ecological restoration efforts. We sampled two sites in French Guyana 17 years after rehabilitation efforts began. The former site was actively regenerated (R) with the leguminous species Clitoria racemosa and Acacia mangium, and the second site was passively regenerated with spontaneous vegetation (Sv). We also sampled soil from a control site without a history of gold mining (F). We performed microcosm soil experiments for 30 days, where trace element speciation and enzyme activities (i.e., FDA, dehydrogenase, β-glucosidase, urease, alkaline and acid phosphatase) were estimated to characterise the behaviour of trace elements and the soil microbial activity. As bioindicators, the use of soil microbial carbon biomass and soil enzyme activities related to the carbon and phosphorus cycles seems to be relevant for assessing soil quality in rehabilitated and regenerated old mining sites. Our results showed that restoration with leguminous species had a positive effect on soil chemical quality and on soil microbial bioindicators, with activities that tended toward natural non-degraded soil (F). Active restoration processes also had a positive effect on Hg speciation by reducing its mobility. While in Sv we found more exchangeable and soluble mercury, in regenerated sites, Hg was mostly bound to organic matter. These results also suggested that enzyme activities and mercury cycles are sensitive to land restoration and must be considered when evaluating

  10. Issues evaluation process at Rocky Flats Plant

    International Nuclear Information System (INIS)

    Smith, L.C.

    1992-01-01

    This report describes the issues evaluation process for Rocky Flats Plant as established in July 1990. The issues evaluation process was initiated February 27, 1990 with a Charter and Process Overview for short-term implementation. The purpose of the process was to determine the projects required for completion before the Phased Resumption of Plutonium Operations. To determine which projects were required, the issues evaluation process and emphasized risk mitigation, based on a ranking system. The purpose of this report is to document the early design of the issues evaluation process to record the methodologies used that continue as the basis for the ongoing Issues Management Program at Rocky Flats Plant

  11. Evaluating Knowledge of Business Processes

    Directory of Open Access Journals (Sweden)

    Andra TURDASAN

    2016-01-01

    Full Text Available Any organization relies on processes/procedures in order to organize the operations. Those processes can be explicit (e.g. textual descriptions of workflow steps or graphical descriptions or implicit (e.g. employees have learned by experience the steps needed to ‘get things done’. A widely acknowledged fact is that processes change due to internal and/or external factors. How can managers make sure the employees know the last version of the process? The current practice is to test employees by multiple-choice questions. This paper proposes a novel knowledge-testing approach based on graphical and interactive questions. To validate our approach, we set up a single-factor controlled experiment with novices and experts in a faculty admission process. The results show that our approach has better results in terms of correct answers.

  12. Quantification of terrestrial ecosystem carbon dynamics in the conterminous United States combining a process-based biogeochemical model and MODIS and AmeriFlux data

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Min; Zhuang, Qianlai; Cook, D.; Coulter, Richard L.; Pekour, Mikhail S.; Scott, Russell L.; Munger, J. W.; Bible, Ken

    2011-08-31

    Satellite remote sensing provides continuous temporal and spatial information of terrestrial ecosystems. Using these remote sensing data and eddy flux measurements and biogeochemical models, such as the Terrestrial Ecosystem Model (TEM), should provide a more adequate quantification of carbon dynamics of terrestrial ecosystems. Here we use Moderate Resolution Imaging Spectroradiometer (MODIS) Enhanced Vegetation Index (EVI), Land Surface Water Index (LSWI) and carbon flux data of AmeriFlux to conduct such a study. We first modify the gross primary production (GPP) modeling in TEM by incorporating EVI and LSWI to account for the effects of the changes of canopy photosynthetic capacity, phenology and water stress. Second, we parameterize and verify the new version of TEM with eddy flux data. We then apply the model to the conterminous United States over the period 2000-2005 at a 0.05-0.05 spatial resolution. We find that the new version of TEM made improvement over the previous version and generally captured the expected temporal and spatial patterns of regional carbon dynamics. We estimate that regional GPP is between 7.02 and 7.78 PgC yr{sup -1} and net primary production (NPP) ranges from 3.81 to 4.38 Pg Cyr{sup -1} and net ecosystem production (NEP) varies within 0.08- 0.73 PgC yr{sup -1} over the period 2000-2005 for the conterminous United States. The uncertainty due to parameterization is 0.34, 0.65 and 0.18 PgC yr{sup -1} for the regional estimates of GPP, NPP and NEP, respectively. The effects of extreme climate and disturbances such as severe drought in 2002 and destructive Hurricane Katrina in 2005 were captured by the model. Our study provides a new independent and more adequate measure of carbon fluxes for the conterminous United States, which will benefit studies of carbon-climate feedback and facilitate policy-making of carbon management and climate.

  13. Quantification of Terrestrial Ecosystem Carbon Dynamics in the Conterminous United States Combining a Process-Based Biogeochemical Model and MODIS and AmeriFlux data

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Min; Zhuang, Qianlai; Cook, David R.; Coulter, Richard L.; Pekour, Mikhail S.; Scott, Russell L.; Munger, J. W.; Bible, Ken

    2011-09-21

    Satellite remote sensing provides continuous temporal and spatial information of terrestrial 24 ecosystems. Using these remote sensing data and eddy flux measurements and biogeochemical 25 models, such as the Terrestrial Ecosystem Model (TEM), should provide a more adequate 26 quantification of carbon dynamics of terrestrial ecosystems. Here we use Moderate Resolution 27 Imaging Spectroradiometer (MODIS) Enhanced Vegetation Index (EVI), Land Surface Water Index 28 (LSWI) and carbon flux data of AmeriFlux to conduct such a study. We first modify the gross primary 29 production (GPP) modeling in TEM by incorporating EVI and LSWI to account for the effects of the 30 changes of canopy photosynthetic capacity, phenology and water stress. Second, we parameterize and 31 verify the new version of TEM with eddy flux data. We then apply the model to the conterminous 32 United States over the period 2000-2005 at a 0.05o ×0.05o spatial resolution. We find that the new 33 version of TEM generally captured the expected temporal and spatial patterns of regional carbon 34 dynamics. We estimate that regional GPP is between 7.02 and 7.78 Pg C yr-1 and net primary 35 production (NPP) ranges from 3.81 to 4.38 Pg C yr-1 and net ecosystem production (NEP) varies 36 within 0.08-0.73 Pg C yr-1 over the period 2000-2005 for the conterminous United States. The 37 uncertainty due to parameterization is 0.34, 0.65 and 0.18 Pg C yr-1 for the regional estimates of GPP, 38 NPP and NEP, respectively. The effects of extreme climate and disturbances such as severe drought in 39 2002 and destructive Hurricane Katrina in 2005 were captured by the model. Our study provides a 40 new independent and more adequate measure of carbon fluxes for the conterminous United States, 41 which will benefit studies of carbon-climate feedback and facilitate policy-making of carbon 42 management and climate.

  14. Quantification of terrestrial ecosystem carbon dynamics in the conterminous United States combining a process-based biogeochemical model and MODIS and AmeriFlux data

    Directory of Open Access Journals (Sweden)

    M. Chen

    2011-09-01

    Full Text Available Satellite remote sensing provides continuous temporal and spatial information of terrestrial ecosystems. Using these remote sensing data and eddy flux measurements and biogeochemical models, such as the Terrestrial Ecosystem Model (TEM, should provide a more adequate quantification of carbon dynamics of terrestrial ecosystems. Here we use Moderate Resolution Imaging Spectroradiometer (MODIS Enhanced Vegetation Index (EVI, Land Surface Water Index (LSWI and carbon flux data of AmeriFlux to conduct such a study. We first modify the gross primary production (GPP modeling in TEM by incorporating EVI and LSWI to account for the effects of the changes of canopy photosynthetic capacity, phenology and water stress. Second, we parameterize and verify the new version of TEM with eddy flux data. We then apply the model to the conterminous United States over the period 2000–2005 at a 0.05° × 0.05° spatial resolution. We find that the new version of TEM made improvement over the previous version and generally captured the expected temporal and spatial patterns of regional carbon dynamics. We estimate that regional GPP is between 7.02 and 7.78 Pg C yr−1 and net primary production (NPP ranges from 3.81 to 4.38 Pg C yr−1 and net ecosystem production (NEP varies within 0.08–0.73 Pg C yr−1 over the period 2000–2005 for the conterminous United States. The uncertainty due to parameterization is 0.34, 0.65 and 0.18 Pg C yr−1 for the regional estimates of GPP, NPP and NEP, respectively. The effects of extreme climate and disturbances such as severe drought in 2002 and destructive Hurricane Katrina in 2005 were captured by the model. Our study provides a new independent and more adequate measure of carbon fluxes for the conterminous United States, which will benefit studies of carbon-climate feedback and facilitate policy-making of carbon management and climate.

  15. Climate Variability and Change in a Eutrophic Great Lakes Freshwater Embayment: Shifting Hydrodynamics and the Potential for Indirect Impacts on Biogeochemical Processes, Carbon Cycling and Hypoxia

    Science.gov (United States)

    Klump, J. V.; Waples, J. T.

    2008-12-01

    Future changes in the climatic regime of the Great Lakes region have the potential to induce a variety of both direct (e.g. thermal) and indirect (e.g. biogeochemical) alterations in ecosystem function. In the case of the later, we have identified a statistically significant shift in wind direction of the average wind field over the Great Lakes basin that is consistent with a southward migration of the dominant summer storm track. In Green Bay (NW Lake Michigan), we have shown that the new wind field has most likely resulted in periods of decreased thermal stratification and an overall decrease in water mass exchange with Lake Michigan. In subsequent studies, aimed at determining the impact of these shifts in the physical climate regime, time series measurements of currents, turbidity, dissolved oxygen, and the Be-7 activity of particulates in bottom sediments, sediment traps, and suspended particulates have been made over a 3 year period. A tracer of short term particle dynamics, Be-7 (half life 53 d) is useful in estimating particle residence times in the water column, along with episodic sediment deposition and erosion rates, and the average number of deposition/erosion cycles a particle experiences prior to permanent burial in the sediments. Be-7 derived estimates of the age of particulate organic carbon cycling between surface sediments and the overlying waters are on the order of months, and are dependent upon resuspension frequency. Remineralization of organic carbon within this actively resuspended pool of material results in estimated decomposition rates for POC ranging 0.08 to 0.04% per day, a rate intermediate between the rapid remineralization of fresh algal material and post-depositional diagenesis. Comparisons between 1989-90 and 2004-06 show a decrease in resuspension frequency, possibly in response to shifts in regional climatic scale dynamics. This appears to result in an increase in the efficiency of trapping of organic matter in the bay and a

  16. Evaluating the risk decision process

    International Nuclear Information System (INIS)

    Hansson, Sven Ove; Ruden, Christina

    2006-01-01

    In order to ensure that risk assessment and risk management serve their purposes efficiently, it is essential to systematically evaluate actual practices. In this overview, it is proposed that such evaluation studies constitute an important field of study that should be recognized as a subdiscipline of regulatory toxicology with its own research issues and its own methodologies. Previous such evaluation studies are summarized. Methods are described that can be used for comparing different risk assessments of one of the same substance, for checking the consistency of harmonized classifications with the available data, for assessing the actual margin of safety (i.e. size of uncertainty factors) in exposure limits, and for comparing different lists of exposure limits. In conclusion, some important problem areas for future evaluation studies are pointed out

  17. A biogeochemical cycle for aluminium?

    Science.gov (United States)

    Exley, Christopher

    2003-09-15

    The elaboration of biogeochemical cycles for elements which are known to be essential for life has enabled a broad appreciation of the homeostatic mechanisms which underlie element essentiality. In particular they can be used effectively to identify any part played by human activities in element cycling and to predict how such activities might impact upon the lithospheric and biospheric availability of an element in the future. The same criteria were the driving force behind the construction of a biogeochemical cycle for aluminium, a non-essential element which is a known ecotoxicant and a suspected health risk in humans. The purpose of this exercise was to examine the concept of a biogeochemical cycle for aluminium and not to review the biogeochemistry of this element. The cycle as presented is rudimentary and qualitative though, even in this nascent form, it is informative and predictive and, for these reasons alone, it is deserving of future quantification. A fully fledged biogeochemical cycle for aluminium should explain the biospheric abundance of this element and whether we should expect its (continued) active involvement in biochemical evolution.

  18. Dry Process Fuel Performance Evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Myung Seung; Song, K. C.; Moon, J. S. and others

    2005-04-15

    The objective of the project is to establish the performance evaluation system of DUPIC fuel during the Phase II R and D. In order to fulfil this objectives, irradiation test of DUPIC fuel was carried out in HANARO using the non-instrumented and SPND-instrumented rig. Also, the analysis on the in-reactor behavior analysis of DUPIC fuel, out-pile test using simulated DUPIC fuel as well as performance and integrity assessment in a commercial reactor were performed during this Phase. The R and D results of the Phase II are summarized as follows : - Performance evaluation of DUPIC fuel via irradiation test in HANARO - Post irradiation examination of irradiated fuel and performance analysis - Development of DUPIC fuel performance code (modified ELESTRES) considering material properties of DUPIC fuel - Irradiation behavior and integrity assessment under the design power envelope of DUPIC fuel - Foundamental technology development of thermal/mechanical performance evaluation using ANSYS (FEM package)

  19. 7 CFR 4284.512 - Evaluation process.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 15 2010-01-01 2010-01-01 false Evaluation process. 4284.512 Section 4284.512 Agriculture Regulations of the Department of Agriculture (Continued) RURAL BUSINESS-COOPERATIVE SERVICE AND....512 Evaluation process. (a) Applications will be evaluated by qualified reviewers appointed by the...

  20. 7 CFR 4284.912 - Evaluation process.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 15 2010-01-01 2010-01-01 false Evaluation process. 4284.912 Section 4284.912 Agriculture Regulations of the Department of Agriculture (Continued) RURAL BUSINESS-COOPERATIVE SERVICE AND... Evaluation process. (a) Applications will be evaluated by agricultural economists or other technical experts...

  1. Investigation of Great Basin big sagebrush and black greasewood as biogeochemical indicators of uranium mineralization. Final report. National Uranium Resource Evaluation

    International Nuclear Information System (INIS)

    Diebold, F.E.; McGrath, S.

    1982-11-01

    The effects of varying phosphate concentrations in natural aqueous systems upon the uptake of uranium by big sagebrush (Artemesia tridentata subsp. tridentata) and black greasewood (Sarcobatus vermiculatus (Hook) Torr.) were investigated. Two separate growth experiments with five drip-flow hyroponic units were used and plant seedlings were grown for 60 days in solutions of varying phosphate and uranium concentrations. Successful growth experiments were obtained only for big sagebrush; black greasewood did not sustain sufficient growth. The phosphate concentration of the water did affect the uptake of uranium by the big sagebrush, and this effect is most pronounced in the region of higher concentrations of uranium in the water. The ratio of the concentration of uranium in the plant to that in the water was observed to decrease with increasing uranium concentration in solution. This is indicative of an absorption barrier in the plants. The field data shows that big sagebrush responds to uranium concentrations in the soil water and not the groundwater. The manifestation of these results is that the use of big sagebrush as a biogeochemical indicator of uranium is not recommended. Since the concentration of phosphate must also be knwon in the water supplying the uranium to the plant, one should analyze this natural aqueous phase as a hydrochemical indicator rather than the big sagebrush

  2. Biogeochemical investigations on processes affecting the transport behaviour of trace elements in the tidal Elbe River; Biogeochemische Prozessuntersuchungen zum Transportverhalten von Spurenelementen in der Tide-Elbe

    Energy Technology Data Exchange (ETDEWEB)

    Hennies, K. [GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. fuer Gewaesserphysik

    1997-12-31

    This work concentrates on distribution and transport of micropollutants in anthropogenically affected estuary systems. Choosing the tidal Elbe River as an example, the influence of microlagae on two important partial processes of the transport regime, the remobilization (a) from undisturbed sediments and (b) from suspended particulate matter, was simulated and quantified in the laboratory. Benthic and planktonic release of Cd, Cu, Pb and Zn into the dissolved phase of the river pelagial were estimated and comparatively evaluated for summer/late summer situation. During that season natural decomposition of suspended particulate matter in the water column thus represents the quantitatively most significant mobilization pathway for particle bound heavy metals in the river section between Hamburg and Glueckstadt. Knowing the composition and heavy metal load of suspended particulate matter, rich in algae, mobilization rates can consequently be calculated for the water column with regard to conditions typical for estuaries. The prognosis of the differing transport behaviour of single heavy metals for greater sections of estuaries is also possible if these rates are implemented into transport-reaction models. (orig.) [Deutsch] Die vorliegende Arbeit befasst sich mit Verteilung und Transport von Spurenschadstoffen in anthropogen belasteten Aestuarsystemen. Am Beispiel der Tide-Elbe wurde der Einfluss von Mikroalgen auf zwei wichtige Teilprozesse des Transportregimes, die Remobilisierung (a) aus ungestoerten Sedimenten und (b) aus suspendierten Schwebstoffen, im Labor simuliert und quantifiziert. Benthische und planktische Freisetzung von Cd, Cu, Pb und Zn in die Loesungsphase des Flusspelagials der Tide-Elbe wurden fuer die Sommer-/Spaetsommer-Situation abgeschaetzt und vergleichend bewertet. Der natuerliche Schwebstoff-Abbau in der Wassersaeule stellt demnach in dieser Jahreszeit im Stromabschnitt zwischen Hamburg und Glueckstadt den quantitativ bedeutsamsten

  3. Coupled biogeochemical cycling of iron and manganese as mediated by microbial siderophores.

    Science.gov (United States)

    Duckworth, Owen W; Bargar, John R; Sposito, Garrison

    2009-08-01

    Siderophores, biogenic chelating agents that facilitate Fe(III) uptake through the formation of strong complexes, also form strong complexes with Mn(III) and exhibit high reactivity with Mn (hydr)oxides, suggesting a pathway by which Mn may disrupt Fe uptake. In this review, we evaluate the major biogeochemical mechanisms by which Fe and Mn may interact through reactions with microbial siderophores: competition for a limited pool of siderophores, sorption of siderophores and metal-siderophore complexes to mineral surfaces, and competitive metal-siderophore complex formation through parallel mineral dissolution pathways. This rich interweaving of chemical processes gives rise to an intricate tapestry of interactions, particularly in respect to the biogeochemical cycling of Fe and Mn in marine ecosystems.

  4. Engineering Pseudomonas stutzeri as a biogeochemical biosensor

    Science.gov (United States)

    Boynton, L.; Cheng, H. Y.; Del Valle, I.; Masiello, C. A.; Silberg, J. J.

    2016-12-01

    Biogeochemical cycles are being drastically altered as a result of anthropogenic activities, such as the burning of fossil fuels and the industrial production of ammonia. We know microbes play a major part in these cycles, but the extent of their biogeochemical roles remains largely uncharacterized due to inadequacies with culturing and measurement. While metagenomics and other -omics methods offer ways to reconstruct microbial communities, these approaches can only give an indication of the functional roles of microbes in a community. These -omics approaches are rapidly being expanded to the point of outpacing our knowledge of functional genes, which highlights an inherent need for analytical methods that non-invasively monitor Earth's processes in real time. Here we aim to exploit synthetic biology methods in order to engineer a ubiquitous denitrifying microbe, Pseudomonas stutzeri that can act as a biosensor in soil and marine environments. By using an easily cultivated microbe that is also common in many environments, we hope to develop a tool that allows us to zoom in on specific aspects of the nitrogen cycle. In order to monitor processes occurring at the genetic level in environments that cannot be resolved with fluorescence-based methods, such as soils, we have developed a system that instead relies on gas production by engineered microbial biosensors. P. stutzeri has been successfully engineered to release a gas, methyl bromide, which can continuously and non-invasively be measured by GC-MS. Similar to using Green Fluorescent Protein, GFP, in the biological sciences, the gene controlling gas production can be linked to those involved in denitrification, thereby creating a quantifiable gas signal that is correlated with microbial activity in the soil. Synthetically engineered microbial biosensors could reveal key aspects of metabolism in soil systems and offer a tool for characterizing the scope and degree of microbial impact on major biogeochemical cycles.

  5. An evaluation of sterilisation processes.

    Science.gov (United States)

    Sladowski, Dariusz; Grabska-Liberek, Iwona; Olkowska-Truchanowicz, Joanna; Lipski, Kamil; Gut, Grzegorz

    2008-11-01

    A sterile environment is one of the basic elements of in vitro cell culture. When choosing an appropriate sterilisation method, the possibility that the physical and chemical properties of the sterilised material could be altered by the sterilisation process itself, should be considered. Avoiding any potential problems of toxicity arising as a consequence of the sterilisation process is essential, not only in in vitro cell culture procedures, but especially in the case of the sterilisation of medical devices which come into contact with human tissue (e.g. catheters, surgical tools, and containers used for transplant preparation and storage). As it is not possible to predict the potential effects of every combination of test material and sterilisation process, we have designed a simple test, which can be easily performed to ensure the absence of cytotoxicity. The test involves the culturing of a non-adherent cell line in direct contact with the test material, in micro-wells attached to the surface of the test device. By using this novel test method, three sterilisation procedures were compared for each material. The results indicated that, neither ionising irradiation nor ethylene oxide left toxic residues on the surface of polystyrene; and that, in the case of steel, neither steam sterilisation nor ethylene oxide left toxic residues on the metal. The cold plasma system, which left toxic residues on the surface of both materials, required a post-sterilisation period of 24 hours in the case of steel, and 10 days in the case of polystyrene, in order to eliminate toxic residues prior to their use. 2008 FRAME.

  6. Stream biogeochemical resilience in the age of Anthropocene

    Science.gov (United States)

    Dong, H.; Creed, I. F.

    2017-12-01

    Recent evidence indicates that biogeochemical cycles are being pushed beyond the tolerance limits of the earth system in the age of the Anthropocene placing terrestrial and aquatic ecosystems at risk. Here, we explored the question: Is there empirical evidence of global atmospheric changes driving losses in stream biogeochemical resilience towards a new normal? Stream biogeochemical resilience is the process of returning to equilibrium conditions after a disturbance and can be measured using three metrics: reactivity (the highest initial response after a disturbance), return rate (the rate of return to equilibrium condition after reactive changes), and variance of the stationary distribution (the signal to noise ratio). Multivariate autoregressive models were used to derive the three metrics for streams along a disturbance gradient - from natural systems where global drivers would dominate, to relatively managed or modified systems where global and local drivers would interact. We observed a loss of biogeochemical resilience in all streams. The key biogeochemical constituent(s) that may be driving loss of biogeochemical resilience were identified from the time series of the stream biogeochemical constituents. Non-stationary trends (detected by Mann-Kendall analysis) and stationary cycles (revealed through Morlet wavelet analysis) were removed, and the standard deviation (SD) of the remaining residuals were analyzed to determine if there was an increase in SD over time that would indicate a pending shift towards a new normal. We observed that nitrate-N and total phosphorus showed behaviours indicative of a pending shift in natural and managed forest systems, but not in agricultural systems. This study provides empirical support that stream ecosystems are showing signs of exceeding planetary boundary tolerance levels and shifting towards a "new normal" in response to global changes, which can be exacerbated by local management activities. Future work will consider

  7. TEXACO GASIFICATION PROCESS - INNOVATIVE TECHNOLOGY EVALUATION REPORT

    Science.gov (United States)

    This report summarizes the evaluation of the Texaco Gasification Process (TGP) conducted under the U.S. Environmental Protection Agency (EPA) Superfund Innovative Technology Evaluation (SITE) Program. The Texaco Gasification Process was developed by Texaco Inc. The TGP is a comm...

  8. Perspectives on the terrestrial organic matter transport and burial along the land-deep sea continuum: Caveats in our understanding of biogeochemical processes and future needs

    Digital Repository Service at National Institute of Oceanography (India)

    Kandasamy, S.; Nath, B.N.

    The natural carbon cycle is immensely intricate to fully understand its sources, fluxes and the processes that are responsible for their cycling in different reservoirs and their balances on a global scale. Anthropogenic perturbations add another...

  9. Integrate Evaluation into the Planning Process.

    Science.gov (United States)

    Camp, William

    1985-01-01

    In an attempt to correct for limitations in the Program Evaluation and Review Technique-Critical Path Method (PERT-CPM), the Graphical Evaluation and Review Technique (GERT) has been developed. This management tool allows for evaluation during the facilities' development process. Two figures and two references are provided. (DCS)

  10. Evaluating the process of ecological restoration

    Directory of Open Access Journals (Sweden)

    Christer Nilsson

    2016-03-01

    Full Text Available We developed a conceptual framework for evaluating the process of ecological restoration and applied it to 10 examples of restoration projects in the northern hemisphere. We identified three major phases, planning, implementation, and monitoring, in the restoration process. We found that evaluation occurred both within and between the three phases, that it included both formal and informal components, and that it often had an impact on the performance of the projects. Most evaluations were short-term and only some parts of them were properly documented. Poor or short-term evaluation of the restoration process creates a risk that inefficient methods will continue to be used, which reduces the efficiency and effectiveness of restoration. To improve the restoration process and to transfer the knowledge to future projects, we argue for more formal, sustained evaluation procedures, involving all relevant stakeholders, and increased and improved documentation and dissemination of the results.

  11. Microbial extracellular enzymes in biogeochemical cycling of ecosystems.

    Science.gov (United States)

    Luo, Ling; Meng, Han; Gu, Ji-Dong

    2017-07-15

    Extracellular enzymes, primarily produced by microorganisms, affect ecosystem processes because of their essential roles in degradation, transformation and mineralization of organic matter. Extracellular enzymes involved in the cycling of carbon (C), nitrogen (N) and phosphorus (P) have been widely investigated in many different ecosystems, and several enzymes have been recognized as key components in regulating C storage and nutrient cycling. In this review, it was the first time to summarize the specific extracellular enzymes related to C storage and nutrient cycling for better understanding the important role of microbial extracellular enzymes in biogeochemical cycling of ecosystems. Subsequently, ecoenzymatic stoichiometry - the relative ratio of extracellular enzyme, has been reviewed and further provided a new perspective for understanding biogeochemical cycling of ecosystems. Finally, the new insights of using microbial extracellular enzyme in indicating biogeochemical cycling and then protecting ecosystems have been suggested. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Coal liquefaction process streams characterization and evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Robbins, G.A.; Brandes, S.D.; Winschel, R.A.; Burke, F.P.

    1992-03-01

    CONSOL R D is conducting a three-year program to characterize process and product streams from direct coal liquefaction process development projects. The program objectives are two-fold: (1) to obtain and provide appropriate samples of coal liquids for the evaluation of analytical methodology, and (2) to support ongoing DOE-sponsored coal liquefaction process development efforts. The two broad objectives have considerable overlap and together serve to provide a bridge between process development and analytical chemistry.

  13. Building a high level sample processing and quality assessment model for biogeochemical measurements: a case study from the ocean acidification community

    Science.gov (United States)

    Thomas, R.; Connell, D.; Spears, T.; Leadbetter, A.; Burger, E. F.

    2016-12-01

    The scientific literature heavily features small-scale studies with the impact of the results extrapolated to regional/global importance. There are on-going initiatives (e.g. OA-ICC, GOA-ON, GEOTRACES, EMODNet Chemistry) aiming to assemble regional to global-scale datasets that are available for trend or meta-analyses. Assessing the quality and comparability of these data requires information about the processing chain from "sampling to spreadsheet". This provenance information needs to be captured and readily available to assess data fitness for purpose. The NOAA Ocean Acidification metadata template was designed in consultation with domain experts for this reason; the core carbonate chemistry variables have 23-37 metadata fields each and for scientists generating these datasets there could appear to be an ever increasing amount of metadata expected to accompany a dataset. While this provenance metadata should be considered essential by those generating or using the data, for those discovering data there is a sliding scale between what is considered discovery metadata (title, abstract, contacts, etc.) versus usage metadata (methodology, environmental setup, lineage, etc.), the split depending on the intended use of data. As part of the OA-ICC's activities, the metadata fields from the NOAA template relevant to the sample processing chain and QA criteria have been factored to develop profiles for, and extensions to, the OM-JSON encoding supported by the PROV ontology. While this work started focused on carbonate chemistry variable specific metadata, the factorization could be applied within the O&M model across other disciplines such as trace metals or contaminants. In a linked data world with a suitable high level model for sample processing and QA available, tools and support can be provided to link reproducible units of metadata (e.g. the standard protocol for a variable as adopted by a community) and simplify the provision of metadata and subsequent discovery.

  14. Biogeochemical response to widespread anoxia in the past ocean

    NARCIS (Netherlands)

    Ruvalcaba Baroni, I.

    2015-01-01

    Oxygen is a key element for life on earth. Oxygen concentrations in the ocean vary greatly in space and time. These changes are regulated by various physical and biogeochemical processes, such as primary productivity, sea surface temperatures and ocean circulation. In the geological past, several

  15. Assimilation of ocean colour data into a Biogeochemical Flux Model of the Eastern Mediterranean Sea

    Directory of Open Access Journals (Sweden)

    G. Triantafyllou

    2007-08-01

    Full Text Available An advanced multivariate sequential data assimilation system has been implemented within the framework of the European MFSTEP project to fit a three-dimensional biogeochemical model of the Eastern Mediterranean to satellite chlorophyll data from the Sea-viewing Wide Field-of-view Sensor (SeaWiFS. The physics are described by the Princeton Ocean Model (POM while the biochemistry of the ecosystem is tackled with the Biogeochemical Flux Model (BFM. The assimilation scheme is based on the Singular Evolutive Extended Kalman (SEEK filter, in which the error statistics were parameterized by means of a suitable set of Empirical Orthogonal Functions (EOFs. To avoid spurious long-range correlations associated with the limited number of EOFs, the filter covariance matrix was given compact support through a radius of influence around every data point location. Hindcast experiments were performed for one year over 1999 and forced with ECMWF 6 h atmospheric fields. The solution of the assimilation system was evaluated against the assimilated data and the MedAtlas climatology, and by assessing the impact of the assimilation on non-observed biogeochemical processes. It is found that the assimilation of SeaWiFS data improves the overall behavior of the BFM model and efficiently removes long term biases from the model despite some difficulties during the spring bloom period. Results, however, suggest the need of subsurface data to enhance the estimation of the ecosystem variables in the deep layers.

  16. Evaluation and processing of nuclear data

    International Nuclear Information System (INIS)

    Pearlstein, S.

    1980-01-01

    The role a nuclear data evaluator plays in obtaining evaluated nuclear data, needed for applications, from measured nuclear data is surveyed. Specific evaluation objectives, problems, and procedures are discussed. The use of nuclear systematics to complement nuclear experiment and theory is described. With the Evaluated Nuclear Data File (ENDF) as an example, the formatting, checking, and processing of nuclear data are discussed as well as the testing of evaluated nuclear data in the calculation of integral benchmark experiments. Other important topics such as the Probability Table Method and interrelation between differential and integral data are also discussed. 25 figures

  17. Evaluation of uranium-enrichment processes

    International Nuclear Information System (INIS)

    Vanstrum, P.R.; Wilcox, W.J. Jr.; McGill, R.M.

    1982-01-01

    The purpose of this paper is to outline some of the methods used in evaluating uranium enrichment processes. The paper shows how one can choose among these many processes and what features are crucial in deciding between them. These features can be grouped into technical and economic factors. The technical factors include separation factor, throughput, inventory of material, and specific power requirement. The economic factors are: (1) capital cost of plant and supporting facilities; (2) operating costs including maintenance costs; and (3) power costs. Besides these essential factors, other factors may also need to be considered. These are: (1) potential for further process improvements; (2) reliability of the process equipment; (3) difficulty of manufacturing and handling the process medium; (4) process flexibility; (5) scaling factors; (6) social factors; (7) political factors. The paper illustrates how these basic technical and economic evaluation factors are applied to real enrichment methods. The gaseous diffusion process is used as a reference process and compared with the following processes: gas centrifuge; advanced isotope separation; thermal diffusion; fractional distillation; mass spectrograph; and mass diffusion. Another point that needs to be considered is that some evaluations of uranium enrichment processes change over a period of time because of advances in technology or changes in economic climate

  18. Using Analytic Hierarchy Process in Textbook Evaluation

    Science.gov (United States)

    Kato, Shigeo

    2014-01-01

    This study demonstrates the application of the analytic hierarchy process (AHP) in English language teaching materials evaluation, focusing in particular on its potential for systematically integrating different components of evaluation criteria in a variety of teaching contexts. AHP is a measurement procedure wherein pairwise comparisons are made…

  19. Biogeochemical Cycling of Sulfur in Soil

    Science.gov (United States)

    Lehmann, J.; Solomon, D.; Janzen, H.; Amelung, W.; Lobe, I.; Martinez, C. E.; Dupreez, C.; Machado, S.

    2002-12-01

    Sulfur is an important element of the global biogeochemical cycle, since it is highly reactive and moves freely among the lithosphere, atmosphere and hydrosphere. Climatic and environmental changes affecting sulfur in the pedosphere will inevitably change the rate and forms of global sulfur cycling which are intertwined with that of carbon, nitrogen and phosphorus. In soil, inorganic sulfur derived from atmospheric deposition or fertilization is largely immobilized and incorporated into soil organic matter (>95%). During the last decades, however, these emissions have been significantly reduced in North America and Europe, and S deficiency can increasingly be observed in crops. This process was accelerated by a change to low-S-containing fertilizers. Therefore, we studied the long-term dynamics of S forms in relation to organic C to evaluate its impact on the soil cycle. Synchrotron-based sulfur K-edge X-ray Absorption Near-Edge Structure spectroscopy (XANES) was used to speciate and quantify the different oxidation states of soil sulfur (organic and inorganic forms of S). Direct measurement of S species in bulk soil indicated the presence of large background on the spectra, which could not easily be corrected without affecting the results. However, humic acid extractions using 0.1 M NaOH/0.4 M NaF mixtures produced better signals, which can even be improved by additional filtration using a 0.2mm membrane filter under pressure. Traditional wet chemical analyses of soil S using hydriodic acid (HI) reduction showed that the major proportion (98%) of total S was present in organic forms, out of which 77-84% were C-bonded S, whereas ester SO4 -S constituted merely 16-23% of the organic S pool in bulk soils. These values were constant regardless of major soil disturbances by landuse and did not change between different particle size fractions. S-XANES spectroscopy, however, showed clear differences of S oxidation states after environmental disturbance of soil and

  20. Self-Assessment in the Evaluation Process.

    Science.gov (United States)

    Koehler, Michael

    1990-01-01

    Describes a four-step process to involve teachers in self-evaluation that results in performance ownership. When supervisors incorporate teacher self-assessments into classroom observation reports, teachers are more willing to engage in follow-up professional growth activities and perceive supervisors as helpers in the process. (MLH)

  1. Evaluation procedure for radioactive waste treatment processes

    International Nuclear Information System (INIS)

    Whitty, W.J.

    1979-11-01

    An aspect of the Los Alamos Scientific Laboratory's nuclear waste management R and D programs has been to develop an evaluation procedure for radioactive waste treatment processes. This report describes the process evaluation method. Process worth is expressed as a numerical index called the Figure-of-Merit (FOM), which is computed using a hierarchial, linear, additive, scoring model with constant criteria weights and nonlinear value functions. A numerical example is used to demonstrate the procedure and to point out some of its strengths and weaknesses. Potential modifications and extensions are discussed, and an extensive reference list is included

  2. Biogeochemical processes in a clay formation in situ experiment: Part E - Equilibrium controls on chemistry of pore water from the Opalinus Clay, Mont Terri Underground Research Laboratory, Switzerland

    International Nuclear Information System (INIS)

    Pearson, F.J.; Tournassat, Christophe; Gaucher, Eric C.

    2011-01-01

    -examination of the measured Ca/Mg activity ratios and consideration of the mineralogical composition of the Opalinus Clay suggested that Ca/Mg cation exchange rather than dolomite saturation may control the ratio of these ions in solution. This re-examination also suggests that the Ca/Mg ratio decreases with increasing pore-water salinity. Several possible reasons for this are proposed. Moreover, it is demonstrated that feldspar equilibria must not be included in Opalinus Clay modelling because feldspars are present only in very small quantities in the formation and because Na/K ratios measured in pore water samples are inconsistent with feldspar saturation. The principal need to improve future modelling is additional or better data on rock properties, in particular: (i) a more detailed identification of phases in the Opalinus Clay that include redox-sensitive elements together with evaluation of their thermodynamic properties; (ii) an improved understanding of the distribution of celestite throughout the Opalinus Clay for Sr/SO 4 concentrations control; (iii) improvements in analytic and thermodynamic data for Ca-Mg rock cation exchange and mineral chemical properties and (iv) the measurement of composition and stability constants of clay minerals actually present in the formation.

  3. Evaluation of nonaqueous processes for nuclear materials

    International Nuclear Information System (INIS)

    Musgrave, B.C.; Grens, J.Z.; Knighton, J.B.; Coops, M.S.

    1983-12-01

    A working group was assigned the task of evaluating the status of nonaqueous processes for nuclear materials and the prospects for successful deployment of these technologies in the future. In the initial evaluation, the study was narrowed to the pyrochemical/pyrometallurgical processes closely related to the processes used for purification of plutonium and its conversion to metal. The status of the chemistry and process hardware were reviewed and the development needs in both chemistry and process equipment technology were evaluated. Finally, the requirements were established for successful deployment of this technology. The status of the technology was evaluated along three lines: (1) first the current applications were examined for completeness, (2) an attempt was made to construct closed-cycle flow sheets for several proposed applications, (3) and finally the status of technical development and future development needs for general applications were reviewed. By using these three evaluations, three different perspectives were constructed that together present a clear picture of how complete the technical development of these processes are

  4. Improving the Process of Student Evaluation

    Directory of Open Access Journals (Sweden)

    Gabriela Neacşu

    2013-12-01

    Full Text Available In this paper we analyzed the process of student evaluation from “Spiru Haret” University. The process under consideration occurs according to a specific Procedure – Process of student evaluation from the Manual of Quality Assurance Procedures, “Spiru Haret” University, Edition 1, 2012. The goal of this procedure, mentioned in the Manual, is to present the student evaluation procedure by using the Blackboard educational platform and other evaluation techniques of quality learning, based on materials developed by teachers of “Spiru Haret” University, as well as corresponding responsibilities, in order to increase the learning process quality and the exigency degree in the examination process, as well as students’ satisfaction measured by accumulated competences. We appreciate that the purpose of this procedure is first and foremost to ensure transparency and objectivity in exam passing decision. After identifying the weaknesses with the “cause - effect” chart, we have sought to improve student evaluation process using PDCA (Plan-Do-Check-Act method, resulting in the design of a new assessment flowchart.

  5. Biogeochemical cycling in the Strait of Georgia.

    Science.gov (United States)

    Johannessen, S C; Macdonald, R W; Burd, B; van Roodselaar, A

    2008-12-01

    The papers in this special issue present the results of a five-year project to study sedimentary biogeochemical processes in the Strait of Georgia, with special emphasis on the near-field of a large municipal outfall. Included in this special issue are overviews of the sedimentology, benthic biology, status of siliceous sponge reefs and distribution of organic carbon in the water column. Other papers address the cycling of contaminants (PCBs, PBDEs) and redox metals in the sediment, a method to map the extent of the influence of municipal effluent from staining on benthic bivalves, and the relationships among geochemical conditions and benthic abundance and diversity. The latter set of papers addresses the role of municipal effluent as a pathway of organic carbon and other contaminants into the Strait of Georgia and the effect of the effluent on benthic geochemistry and biology.

  6. Study on team evaluation. Team process model for team evaluation

    International Nuclear Information System (INIS)

    Sasou Kunihide; Ebisu, Mitsuhiro; Hirose, Ayako

    2004-01-01

    Several studies have been done to evaluate or improve team performance in nuclear and aviation industries. Crew resource management is the typical example. In addition, team evaluation recently gathers interests in other teams of lawyers, medical staff, accountants, psychiatrics, executive, etc. However, the most evaluation methods focus on the results of team behavior that can be observed through training or actual business situations. What is expected team is not only resolving problems but also training younger members being destined to lead the next generation. Therefore, the authors set the final goal of this study establishing a series of methods to evaluate and improve teams inclusively such as decision making, motivation, staffing, etc. As the first step, this study develops team process model describing viewpoints for the evaluation. The team process is defined as some kinds of power that activate or inactivate competency of individuals that is the components of team's competency. To find the team process, the authors discussed the merits of team behavior with the experienced training instructors and shift supervisors of nuclear/thermal power plants. The discussion finds four team merits and many components to realize those team merits. Classifying those components into eight groups of team processes such as 'Orientation', 'Decision Making', 'Power and Responsibility', 'Workload Management', 'Professional Trust', 'Motivation', 'Training' and 'staffing', the authors propose Team Process Model with two to four sub processes in each team process. In the future, the authors will develop methods to evaluate some of the team processes for nuclear/thermal power plant operation teams. (author)

  7. Division of Biogeochemical Ecology FY-1985 highlights

    International Nuclear Information System (INIS)

    Anon.

    1985-01-01

    The primary goal of the Division is to understand the various biogeochemical processes, both in aquatic and terrestrial systems, that occur in the southeastern United States, including the Savannah River Plant. Both applied and basic approaches are being used to enhance understanding of the biogeochemical cycles of certain elements and trace contaminants, either in inorganic or organic states, and in stable or radioactive forms. Specific examples of studies conducted during the past year include: (1) ecosystem modeling and implementation of a computer model to predict the fate, behavior and transport of heavy metals and radionuclides in SRP streams, (2) laboratory and greenhouse studies on the environmental chemistry of an organo-borate in the soil-plant system, (3) research on the behavior and fate of actinide elements and other long-lived radioisotopes in terrestrial and aquatic ecosystems, and (4) responses of pine plantations to organic waste fertilization. Major findings of these studies are summarized. The chemical speciation-transport model MEXAMS (Metal Exposure Analysis Modeling System) was implemented to provide predictive capabilities for the transport of heavy metals and radionuclides in SRP aquatic systems. The basic components of the model are the geochemical model MINTEQ, and an aquatic exposure assessment model, EXAMS. The interfacing of these two models provides information on the complex chemistry and behavior of metals, as well as the transport processes influencing their migration and ultimate fate in aquatic systems. Test simulations for Cd, Cu, and Ni speciation in various SRP streams were conducted. The results indicated that the MEXAMS model will be a useful tool in predicting the transport and fate of metals in SRP streams

  8. Early Phase Process Evaluation: Industrial Practices

    Directory of Open Access Journals (Sweden)

    Zulfan Adi Putra

    2016-09-01

    Full Text Available Process route evaluation is a part of research and development (R&D works in an industrial chemical project life cycle. In this early phase, good process evaluation, including process synthesis and designs, provide guidance’s on the R&D project. The paper aimed to collect practical methods used in this early phase process route evaluation from author’s 10 years of industrial experiences.  The collected methods range from forward-backward process synthesis, functional process design, use of cost estimation, and applications of Monte Carlo simulation. Led by a good project management (e.g. via a stage-gate approach use of these methods have shown beneficial results. Some important results are strong arguments on whether or not the project will continue, as well as relevant technical and economic issues identified during this early phase process synthesis and design. Later on, these issues become guidance’s to the follow-up project, if it is continued.

  9. Student evaluations of the portfolio process.

    Science.gov (United States)

    Murphy, John E; Airey, Tatum C; Bisso, Andrea M; Slack, Marion K

    2011-09-10

    To evaluate pharmacy students' perceived benefits of the portfolio process and to gather suggestions for improving the process. A questionnaire was designed and administered to 250 first-, second-, and third-year pharmacy students at the University of Arizona College of Pharmacy. Although the objectives of the portfolio process were for students to understand the expected outcomes, understand the impact of extracurricular activities on attaining competencies, identify what should be learned, identify their strengths and weaknesses, and modify their approach to learning, overall students perceived the portfolio process as having less than moderate benefit. First-year students wanted more examples of portfolios while second- and third-year students suggested that more time with their advisor would be beneficial. The portfolio process will continue to be refined and efforts made to improve students' perceptions of the process as it is intended to develop the self-assessments skills they will need to improve their knowledge and professional skills throughout their pharmacy careers.

  10. Materials evaluation for a transuranic processing facility

    International Nuclear Information System (INIS)

    Barker, S.A.; Schwenk, E.B.; Divine, J.R.

    1990-11-01

    The Westinghouse Hanford Company, with the assistance of the Pacific Northwest Laboratory, is developing a transuranium extraction process for preheating double-shell tank wastes at the Hanford Site to reduce the volume of transuranic waste being sent to a repository. The bench- scale transuranium extraction process development is reaching a stage where a pilot plant design has begun for the construction of a facility in the existing B Plant. Because of the potential corrosivity of neutralized cladding removal waste process streams, existing embedded piping alloys in B Plant are being evaluated and ''new'' alloys are being selected for the full-scale plant screening corrosion tests. Once the waste is acidified with HNO 3 , some of the process streams that are high in F - and low in Al and zr can produce corrosion rates exceeding 30,000 mil/yr in austenitic alloys. Initial results results are reported concerning the applicability of existing plant materials to withstand expected process solutions and conditions to help determine the feasibility of locating the plant at the selected facility. In addition, process changes are presented that should make the process solutions less corrosive to the existing materials. Experimental work confirms that Hastelloy B is unsatisfactory for the expected process solutions; type 304L, 347 and 309S stainless steels are satisfactory for service at room temperature and 60 degrees C, if process stream complexing is performed. Inconel 625 was satisfactory for all solutions. 17 refs., 5 figs., 8 tabs

  11. An evaluation approach for alarm processing improvement

    International Nuclear Information System (INIS)

    Kim, Jung-Taek; Lee, Dong-Young; Hwang, In-Koo; Park, Jae-Chang

    1997-01-01

    In light of the need to improve MMIS of NPPs, the advanced I and C research team of KAERI has embarked on developing an Alarm and Diagnosis-Integrated Operator Support System, called ADIOS, to filter or suppress unnecessary or nuisance alarms and diagnose abnormality of the plant process. ADIOS has been built in an object-oriented AI environment of G-2 expert system software tool, as presented in a companion paper. ADIOS then is evaluated according to the plan in three steps; (1) preliminary tests to refine the knowledge base and inference structure of ADIOS in such a dynamic environment, and also to evaluate the appropriateness of alarm-processing algorithms; (2) to ensure correctness, consistency, and completeness in the knowledge base using COKEP (Checker Of Knowledge base using Extended Petri net); and (3) the cognitive performance evaluation using the Simulation Analyzer with a Cognitive Operator Model (SACOM) in the KAERI's Integrated Test Facility (ITF). (author). 5 figs, 1 tab

  12. Evaluation of control strategies in forming processes

    Directory of Open Access Journals (Sweden)

    Calmano Stefan

    2015-01-01

    Full Text Available Products of forming processes are subject to quality fluctuations due to uncertainty in semi-finished part properties as well as process conditions and environment. An approach to cope with these uncertainties is the implementation of a closed-loop control taking into account the actual product properties measured by sensors or estimated by a mathematical process model. Both methods of uncertainty control trade off with a financial effort. In case of sensor integration the effort is the cost of the sensor including signal processing as well as the design and manufacturing effort for integration. In case of an estimation model the effort is mainly determined by the time and knowledge needed to derive the model, identify the parameters and implement the model into the PLC. The risk of mismatch between model and reality as well as the risk of wrong parameter identification can be assumed as additional uncertainty (model uncertainty. This paper evaluates controlled and additional uncertainty by taking into account process boundary conditions like the degree of fluctuations in semi-finished part properties. The proposed evaluation is demonstrated by the analysis of exemplary processes.

  13. Benthic-Pelagic Coupling in Biogeochemical and Climate Models: Existing Approaches, Recent developments and Roadblocks

    Science.gov (United States)

    Arndt, Sandra

    2016-04-01

    Marine sediments are key components in the Earth System. They host the largest carbon reservoir on Earth, provide the only long term sink for atmospheric CO2, recycle nutrients and represent the most important climate archive. Biogeochemical processes in marine sediments are thus essential for our understanding of the global biogeochemical cycles and climate. They are first and foremost, donor controlled and, thus, driven by the rain of particulate material from the euphotic zone and influenced by the overlying bottom water. Geochemical species may undergo several recycling loops (e.g. authigenic mineral precipitation/dissolution) before they are either buried or diffuse back to the water column. The tightly coupled and complex pelagic and benthic process interplay thus delays recycling flux, significantly modifies the depositional signal and controls the long-term removal of carbon from the ocean-atmosphere system. Despite the importance of this mutual interaction, coupled regional/global biogeochemical models and (paleo)climate models, which are designed to assess and quantify the transformations and fluxes of carbon and nutrients and evaluate their response to past and future perturbations of the climate system either completely neglect marine sediments or incorporate a highly simplified representation of benthic processes. On the other end of the spectrum, coupled, multi-component state-of-the-art early diagenetic models have been successfully developed and applied over the past decades to reproduce observations and quantify sediment-water exchange fluxes, but cannot easily be coupled to pelagic models. The primary constraint here is the high computation cost of simulating all of the essential redox and equilibrium reactions within marine sediments that control carbon burial and benthic recycling fluxes: a barrier that is easily exacerbated if a variety of benthic environments are to be spatially resolved. This presentation provides an integrative overview of

  14. Preliminary evaluation of alternative waste form solidification processes. Volume II. Evaluation of the processes

    International Nuclear Information System (INIS)

    1980-08-01

    This Volume II presents engineering feasibility evaluations of the eleven processes for solidification of nuclear high-level liquid wastes (HHLW) described in Volume I of this report. Each evaluation was based in a systematic assessment of the process in respect to six principal evaluation criteria: complexity of process; state of development; safety; process requirements; development work required; and facility requirements. The principal criteria were further subdivided into a total of 22 subcriteria, each of which was assigned a weight. Each process was then assigned a figure of merit, on a scale of 1 to 10, for each of the subcriteria. A total rating was obtained for each process by summing the products of the subcriteria ratings and the subcriteria weights. The evaluations were based on the process descriptions presented in Volume I of this report, supplemented by information obtained from the literature, including publications by the originators of the various processes. Waste form properties were, in general, not evaluated. This document describes the approach which was taken, the developent and application of the rating criteria and subcriteria, and the evaluation results. A series of appendices set forth summary descriptions of the processes and the ratings, together with the complete numerical ratings assigned; two appendices present further technical details on the rating process

  15. Does supplier evaluation impact process improvement?

    Directory of Open Access Journals (Sweden)

    Shiva Prasad h c

    2016-09-01

    Full Text Available Purpose: The research explores and examines factors for supplier evaluation and its impact on process improvement particularly aiming on a steel pipe manufacturing firm in Gujarat, India. Design/Methodology/approach: The conceptual research framework was developed and hypotheses were stated considering the analysis of literature and discussions with the managers and engineers of a steel pipe manufacturing company in Gujarat, India. Data was collected using in-depth interview. The questionnaire primarily involves the perception of evaluation of supplier. Factors influencing supplier evaluation and its influence on process improvement is also examined in this study. The model testing and validation was done using partial least square method. Outcomes signified that the factors that influence evaluation of the supplier are quality, cost, delivery and supplier relationship management. Findings: The study depicted that quality and cost factors for supplier evaluation are insignificant. The delivery and supplier relationship management have significant influence on evaluation of the supplier. The research also depicted that supplier evaluation has significant influence on process improvement. Research limitations/implications: The study has been made specifically for ABC steel pipe manufacturing industry in Gujarat, India and may not be appropriate to the other industries or any parts of the world. There is a possibility of response bias as the conclusions of this research was interpreted on survey responses taken from the employees of case study company, so it is suggested that future research can overcome this problem by employing various methodologies in addition to surveys like carrying out focus group and in-depth interviews, brainstorming sessions with the experts etc. Originality/value: Many researchers have considered quality, cost and delivery as the factors for evaluating the suppliers. But for a company it is quintessential to have good

  16. Thermal processes evaluation for RWMC wastes

    International Nuclear Information System (INIS)

    1991-01-01

    The objective of this activity was to provide a white paper that identifies, collects information, and presents a preliminary evaluation of ''core'' thermal technologies that could be applied to RWMC stored and buried mixed waste. This paper presents the results of the following activities: General thermal technology identification, collection of technical and cost information on each technology, identification of thermal technologies applicable to RWMC waste, evaluation of each technology as applied to RWMC waste in seven process attributes, scoring each technology on a one to five scale (five highest) in each process attribute. Reaching conclusions about the superiority of one technology over others is not advised based on this preliminary study alone. However, the highly rated technologies (i.e., overall score of 2.9 or better) are worthy of a more detailed evaluation. The next step should be a more detailed evaluation of the technologies that includes onsite visits with operational facilities, preconceptual treatment facility design analysis, and visits with developers for emerging technologies. 2 figs., 6 tabs

  17. Marginal Ice Zone: Biogeochemical Sampling with Gliders

    Science.gov (United States)

    2015-09-30

    1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Marginal Ice Zone: Biogeochemical Sampling with Gliders...under the ice and in the marginal ice zone. The project specific goals are to develop biogeochemical and optical proxies for glider optics; to use the...water, in the marginal ice zone, and under the ice; to use glider optical measurements to compute fields of rates of photosynthetic carbon fixation

  18. Evaluating Process Effectiveness to Reduce Risk

    Science.gov (United States)

    Shepherd, Christena C.

    2017-01-01

    security; loss of confidence in government; failure of publicly funded projects; damage to the environment; ethics violations, and the list goes on; with local, national and even international consequences. The Plan-Do-Check-Act process, also known as the "process approach" can be used at any time to establish and standardize a process, and it can also be used to check periodically for "process creep" (i.e., informal, unauthorized changes that have occurred over time), any necessary updates and improvements. While ISO 9001 compliance is not mandated for all government agencies, if interpreted correctly, it can be useful in establishing a framework and implementing effective management systems and processes.4 Another method that can be used to evaluate effectiveness is the scorecard definitions in Mallory's Process Management Standard5 as a basis for evaluating work on the process level on effective, and continuously improved and improving processes. With processes on the lower end of the scale, agencies are vulnerable to a great many risks, with employees and managers making up many of the rules as they go, leading to the above listed negative results. Without clear guidance for nominal operations, off-nominal situations can, and do, increase the likelihood of chaos. In an increasingly technical environment, with inter-agency communication and collaboration becoming the norm, agencies need to come to grips with the fact that processes can become rapidly outdated, and that the technical community should take on an increased role in the maturation of the agency's processes. Industry has long known that effective processes are also efficient, and process improvement methods such as Kaizen, Lean, Six Sigma, 5S, and mistake proofing lead to increased productivity, improved quality, and decreased cost. Again, government agencies have different concerns, but inefficiencies and mistakes can have dire and wide reaching consequences for the public that they serve. While no one goes

  19. Marine and estuarine natural microbial biofilms: ecological and biogeochemical dimensions

    Directory of Open Access Journals (Sweden)

    O. Roger Anderson

    2016-08-01

    Full Text Available Marine and estuarine microbial biofilms are ubiquitously distributed worldwide and are increasingly of interest in basic and applied sciences because of their unique structural and functional features that make them remarkably different from the biota in the plankton. This is a review of some current scientific knowledge of naturally occurring microbial marine and estuarine biofilms including prokaryotic and microeukaryotic biota, but excluding research specifically on engineering and applied aspects of biofilms such as biofouling. Because the microbial communities including bacteria and protists are integral to the fundamental ecological and biogeochemical processes that support biofilm communities, particular attention is given to the structural and ecological aspects of microbial biofilm formation, succession, and maturation, as well as the dynamics of the interactions of the microbiota in biofilms. The intent is to highlight current state of scientific knowledge and possible avenues of future productive research, especially focusing on the ecological and biogeochemical dimensions.

  20. The Microbial Engines That Drive Earth’s Biogeochemical Cycles

    Science.gov (United States)

    Falkowski, Paul G.; Fenchel, Tom; Delong, Edward F.

    2008-05-01

    Virtually all nonequilibrium electron transfers on Earth are driven by a set of nanobiological machines composed largely of multimeric protein complexes associated with a small number of prosthetic groups. These machines evolved exclusively in microbes early in our planet’s history yet, despite their antiquity, are highly conserved. Hence, although there is enormous genetic diversity in nature, there remains a relatively stable set of core genes coding for the major redox reactions essential for life and biogeochemical cycles. These genes created and coevolved with biogeochemical cycles and were passed from microbe to microbe primarily by horizontal gene transfer. A major challenge in the coming decades is to understand how these machines evolved, how they work, and the processes that control their activity on both molecular and planetary scales.

  1. Biogeochemical sensor performance in the SOCCOM profiling float array

    Science.gov (United States)

    Johnson, Kenneth S.; Plant, Joshua N.; Coletti, Luke J.; Jannasch, Hans W.; Sakamoto, Carole M.; Riser, Stephen C.; Swift, Dana D.; Williams, Nancy L.; Boss, Emmanuel; Haëntjens, Nils; Talley, Lynne D.; Sarmiento, Jorge L.

    2017-08-01

    The Southern Ocean Carbon and Climate Observations and Modeling (SOCCOM) program has begun deploying a large array of biogeochemical sensors on profiling floats in the Southern Ocean. As of February 2016, 86 floats have been deployed. Here the focus is on 56 floats with quality-controlled and adjusted data that have been in the water at least 6 months. The floats carry oxygen, nitrate, pH, chlorophyll fluorescence, and optical backscatter sensors. The raw data generated by these sensors can suffer from inaccurate initial calibrations and from sensor drift over time. Procedures to correct the data are defined. The initial accuracy of the adjusted concentrations is assessed by comparing the corrected data to laboratory measurements made on samples collected by a hydrographic cast with a rosette sampler at the float deployment station. The long-term accuracy of the corrected data is compared to the GLODAPv2 data set whenever a float made a profile within 20 km of a GLODAPv2 station. Based on these assessments, the fleet average oxygen data are accurate to 1 ± 1%, nitrate to within 0.5 ± 0.5 µmol kg-1, and pH to 0.005 ± 0.007, where the error limit is 1 standard deviation of the fleet data. The bio-optical measurements of chlorophyll fluorescence and optical backscatter are used to estimate chlorophyll a and particulate organic carbon concentration. The particulate organic carbon concentrations inferred from optical backscatter appear accurate to with 35 mg C m-3 or 20%, whichever is larger. Factors affecting the accuracy of the estimated chlorophyll a concentrations are evaluated.Plain Language SummaryThe ocean science community must move toward greater use of autonomous platforms and sensors if we are to extend our knowledge of the effects of climate driven change within the ocean. Essential to this shift in observing strategies is an understanding of the performance that can be obtained from biogeochemical sensors on platforms deployed for years and the

  2. Spatial heterogeneity in biogeochemical transport on Arctic hill slopes

    Science.gov (United States)

    Risser, R.; Harms, T.; Jones, J.

    2013-12-01

    Water tracks, saturated regions of the hill slope in permafrosted Arctic catchments, likely deliver the majority of water entering streams in these regions, and may play a central role in delivery of nutrients. Fate of dissolved nutrients and carbon as they are transported in water tracks has a substantial effect on stream ecosystems, as water tracks may cover up to 35% of the catchment land area. Water tracks are distinguished from adjacent areas of the hillslope by higher rates of hydrologic transport, greater woody biomass, and increased pools of nutrients. Substantial spatial heterogeneity within and between water tracks may influence their role in transfer of materials between the terrestrial and aquatic landscape. We examined spatial variability of hydrologic and chemical characteristics within and between water tracks in the Kuparuk Basin of northern Alaska to increase understanding of the factors influencing nutrient export from arctic catchments. We studied a sedge-dominated water track with perennial surface water flow with shrub-dominated water tracks containing intermittent surface flow. Nominal transit times of water in the perennial site was 5 hours, compared to 15.5 h in an ephemeral track over a 50 meter reach, indicating substantial variation in water residence time and opportunity for biogeochemical reaction across sites. We evaluated spatial heterogeneity in biogeochemical characteristics within 25-m reaches at each site with a grain size of 10 m. Dissolved CH4 concentration was elevated above atmospheric equilibrium only at the perennial water track, where CH4 concentration varied by more than 15-fold within the water track, indicating hot spots of anaerobic microbial activity. Dissolved CO2 concentration was 9 times greater on average at the perennial water track, compared to the ephemeral site, suggesting that continuous water flow supports more rapid microbial activity. CO2 concentration was also more variable in the perennial water track

  3. Biotic and Biogeochemical Feedbacks to Climate Change

    Science.gov (United States)

    Torn, M. S.; Harte, J.

    2002-12-01

    Feedbacks to paleoclimate change are evident in ice core records showing correlations of temperature with carbon dioxide, nitrous oxide, and methane. Such feedbacks may be explained by plant and microbial responses to climate change, and are likely to occur under impending climate warming, as evidenced by results of ecosystem climate manipulation experiments and biometeorological observations along ecological and climate gradients. Ecosystems exert considerable influence on climate, by controlling the energy and water balance of the land surface as well as being sinks and sources of greenhouse gases. This presentation will focus on biotic and biogeochemical climate feedbacks on decadal to century time scales, emphasizing carbon storage and energy exchange. In addition to the direct effects of climate on decomposition rates and of climate and CO2 on plant productivity, climate change can alter species composition; because plant species differ in their surface properties, productivity, phenology, and chemistry, climate-induced changes in plant species composition can exert a large influence on the magnitude and sign of climate feedbacks. We discuss the effects of plant species on ecosystem carbon storage that result from characteristic differences in plant biomass and lifetime, allocation to roots vs. leaves, litter quality, microclimate for decomposition and the ultimate stabilization of soil organic matter. We compare the effect of species transitions on transpiration, albedo, and other surface properties, with the effect of elevated CO2 and warming on single species' surface exchange. Global change models and experiments that investigate the effect of climate only on existing vegetation may miss the biggest impacts of climate change on biogeochemical cycling and feedbacks. Quantification of feedbacks will require understanding how species composition and long-term soil processes will change under global warming. Although no single approach, be it experimental

  4. PEATBOG: a biogeochemical model for analyzing coupled carbon and nitrogen dynamics in northern peatlands

    Science.gov (United States)

    Wu, Y.; Blodau, C.

    2013-08-01

    Elevated nitrogen deposition and climate change alter the vegetation communities and carbon (C) and nitrogen (N) cycling in peatlands. To address this issue we developed a new process-oriented biogeochemical model (PEATBOG) for analyzing coupled carbon and nitrogen dynamics in northern peatlands. The model consists of four submodels, which simulate: (1) daily water table depth and depth profiles of soil moisture, temperature and oxygen levels; (2) competition among three plants functional types (PFTs), production and litter production of plants; (3) decomposition of peat; and (4) production, consumption, diffusion and export of dissolved C and N species in soil water. The model is novel in the integration of the C and N cycles, the explicit spatial resolution belowground, the consistent conceptualization of movement of water and solutes, the incorporation of stoichiometric controls on elemental fluxes and a consistent conceptualization of C and N reactivity in vegetation and soil organic matter. The model was evaluated for the Mer Bleue Bog, near Ottawa, Ontario, with regards to simulation of soil moisture and temperature and the most important processes in the C and N cycles. Model sensitivity was tested for nitrogen input, precipitation, and temperature, and the choices of the most uncertain parameters were justified. A simulation of nitrogen deposition over 40 yr demonstrates the advantages of the PEATBOG model in tracking biogeochemical effects and vegetation change in the ecosystem.

  5. Facial Edema Evaluation Using Digital Image Processing

    Directory of Open Access Journals (Sweden)

    A. E. Villafuerte-Nuñez

    2013-01-01

    Full Text Available The main objective of the facial edema evaluation is providing the needed information to determine the effectiveness of the anti-inflammatory drugs in development. This paper presents a system that measures the four main variables present in facial edemas: trismus, blush (coloration, temperature, and inflammation. Measurements are obtained by using image processing and the combination of different devices such as a projector, a PC, a digital camera, a thermographic camera, and a cephalostat. Data analysis and processing are performed using MATLAB. Facial inflammation is measured by comparing three-dimensional reconstructions of inflammatory variations using the fringe projection technique. Trismus is measured by converting pixels to centimeters in a digitally obtained image of an open mouth. Blushing changes are measured by obtaining and comparing the RGB histograms from facial edema images at different times. Finally, temperature changes are measured using a thermographic camera. Some tests using controlled measurements of every variable are presented in this paper. The results allow evaluating the measurement system before its use in a real test, using the pain model approved by the US Food and Drug Administration (FDA, which consists in extracting the third molar to generate the facial edema.

  6. Coal liquefaction process streams characterization and evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, J.A.; Linehan, J.C.; Robins, W.H. (Battelle Pacific Northwest Lab., Richland, WA (United States))

    1992-07-01

    Under contract from the DOE , and in association with CONSOL Inc., Battelle, Pacific Northwest Laboratory (PNL) evaluated four principal and several complementary techniques for the analysis of non-distillable direct coal liquefaction materials in support of process development. Field desorption mass spectrometry (FDMS) and nuclear magnetic resonance (NMR) spectroscopic methods were examined for potential usefulness as techniques to elucidate the chemical structure of residual (nondistillable) direct coal liquefaction derived materials. Supercritical fluid extraction (SFE) and supercritical fluid chromatography/mass spectrometry (SFC/MS) were evaluated for effectiveness in compound-class separation and identification of residual materials. Liquid chromatography (including microcolumn) separation techniques, gas chromatography/mass spectrometry (GC/MS), mass spectrometry/mass spectrometry (MS/MS), and GC/Fourier transform infrared (FTIR) spectroscopy methods were applied to supercritical fluid extracts. The full report authored by the PNL researchers is presented here. The following assessment briefly highlights the major findings of the project, and evaluates the potential of the methods for application to coal liquefaction materials. These results will be incorporated by CONSOL into a general overview of the application of novel analytical techniques to coal-derived materials at the conclusion of CONSOL's contract.

  7. The evaluation process of short training sessions in organizations

    NARCIS (Netherlands)

    Overschie, M.G.F.; Lukosch, H.K.; De Vries, P.

    This paper presents a critical reflection of the evaluation of learning processes in organizations. Based on learning and evaluation theories and concepts we discuss qualitative and quantitative evaluation processes, and its relationship to short training sessions to foster sustainable development.

  8. Estimating impacts of lichens and bryophytes on global biogeochemical cycles

    Science.gov (United States)

    Porada, Philipp; Weber, Bettina; Elbert, Wolfgang; Pöschl, Ulrich; Kleidon, Axel

    2014-02-01

    Lichens and bryophytes may significantly affect global biogeochemical cycles by fixation of nitrogen and biotic enhancement of surface weathering rates. Most of the studies suggesting these effects, however, are either conceptual or rely on upscaling of regional estimates to obtain global numbers. Here we use a different method, based on estimates of net carbon uptake, to quantify the impacts of lichens and bryophytes on biogeochemical cycles at the global scale. We focus on three processes, namely, nitrogen fixation, phosphorus uptake, and chemical weathering. Our estimates have the form of potential rates, which means that we quantify the amount of nitrogen and phosphorus needed by the organisms to build up biomass, also accounting for resorption and leaching of nutrients. Subsequently, we use potential phosphorus uptake on bare ground to estimate chemical weathering by the organisms, assuming that they release weathering agents to obtain phosphorus. The predicted requirement for nitrogen ranges from 3.5 to 34 Tgyr-1 and for phosphorus it ranges from 0.46 to 4.6 Tgyr-1. Estimates of chemical weathering are between 0.058 and 1.1 km3 yr-1 of rock. These values seem to have a realistic order of magnitude, and they support the notion that lichens and bryophytes have the potential to play an important role for biogeochemical cycles.

  9. Process to identify and evaluate restoration options

    International Nuclear Information System (INIS)

    Strand, J.; Senner, S.; Weiner, A.; Rabinowitch, S.; Brodersen, M.; Rice, K.; Klinge, K.; MacMullin, S.; Yender, R.; Thompson, R.

    1993-01-01

    The restoration planning process has yielded a number of possible alternatives for restoring resources and services injured by the Exxon Valdez oil spill. They were developed by resource managers, scientists, and the public, taking into consideration the results of damage assessment and restoration studies and information from the scientific literature. The alternatives thus far identified include no action natural recovery, management of human uses, manipulation of resources, habitat protection and acquisition, acquisition of equivalent resources, and combinations of the above. Each alternative consists of a different mix of resource- or service-specific restoration options. To decide whether it was appropriate to spend restoration funds on a particular resource or service, first criteria had to be developed that evaluated available evidence for consequential injury and the adequacy and rate of natural recovery. Then, recognizing the range of effective restoration options, a second set of criteria was applied to determine which restoration options were the most beneficial. These criteria included technical feasibility, potential to improve the rate or degree of recovery, the relationship of expected costs to benefits, cost effectiveness, and the potential to restore the ecosystem as a whole. The restoration options considered to be most beneficial will be grouped together in several or more of the above alternatives and presented in a draft restoration plan. They will be further evaluated in a companion draft environmental impact statement

  10. Econometric Methodology of Monopolization Process Evaluation

    Directory of Open Access Journals (Sweden)

    Dmitrijs Skoruks

    2014-06-01

    Full Text Available The research “Econometric Methodology of Monopolization Process Evaluation” gives a perspective description of monopolization process’ nature, occurrence source, development procedure and internal conjuncture specifics, as well as providing an example of modern econometrical method application within a unified framework of market competition analysis for the purpose of conducting a quantitative competition evaluation on an industry level for practical use in both private and public sectors. The main question of the aforementioned research is the definition and quantitative analysis of monopolization effects in modern day globalized markets, while con- structing an empirical model of the econometric analysis, based on the use of in- ternational historical experience of monopoly formations standings, with the goal of introducing a further development scheme for the use of both econometrical and statistical instruments in line with the forecasting and business research need of enterprises and regulatory functions of the public sector. The current research uses a vast variety of monopolization evaluation ratios and their econometrical updates on companies that are involved in the study procedure in order to detect and scallar measure their market monopolizing potential, based on the implemented acquired market positions, turnover shares and competition policies.

  11. Quality evaluation of processed clay soil samples.

    Science.gov (United States)

    Steiner-Asiedu, Matilda; Harrison, Obed Akwaa; Vuvor, Frederick; Tano-Debrah, Kwaku

    2016-01-01

    This study assessed the microbial quality of clay samples sold on two of the major Ghanaian markets. The study was a cross-sectional assessing the evaluation of processed clay and effects it has on the nutrition of the consumers in the political capital town of Ghana. The items for the examination was processed clay soil samples. Staphylococcus spp and fecal coliforms including Klebsiella, Escherichia, and Shigella and Enterobacterspp were isolated from the clay samples. Samples from the Kaneshie market in Accra recorded the highest total viable counts 6.5 Log cfu/g and Staphylococcal count 5.8 Log cfu/g. For fecal coliforms, Madina market samples had the highest count 6.5 Log cfu/g and also recorded the highest levels of yeast and mould. For Koforidua, total viable count was highest in the samples from the Zongo market 6.3 Log cfu/g. Central market samples had the highest count of fecal coliforms 4.6 Log cfu/g and yeasts and moulds 6.5 Log cfu/g. "Small" market recorded the highest staphylococcal count 6.2 Log cfu/g. The water activity of the clay samples were low, and ranged between 0.65±0.01 and 0.66±0.00 for samples collected from Koforidua and Accra respectively. The clay samples were found to contain Klebsiella spp. Escherichia, Enterobacter, Shigella spp. staphylococcus spp., yeast and mould. These have health implications when consumed.

  12. Potential biogeochemical and biogeophysical consequences of afforestation in North America

    Science.gov (United States)

    O'Halloran, T. L.; Law, B. E.; Baldocchi, D. D.; Bonan, G. B.; Randerson, J. T.

    2009-12-01

    Sequestering atmospheric carbon dioxide via afforestation is an accepted method towards mitigating climate change under the Kyoto Protocol CDM (Clean Development Mechanism) and may see significant expansion in North America if motivated by new treaties or implementation of cap and trade in the United States. However, there are concomitant changes to biogeophysical processes/properties (e.g. evapotranspiration, albedo) that can enhance or dampen the climate benefits of increasing carbon uptake via changes in land use. These mechanisms have been examined previously, but mostly as modeling scenarios of deforestation. In light of increasing potential for implementation, afforestation scenarios have recently received more attention from the modeling community. Here we present a synthesis of flux tower measurements to define characteristics of carbon and energy processing in the four key biomes most likely involved in afforestation projects: croplands, grasslands, deciduous broadleaf forests, and evergreen needleleaf forests. We use nearly 100 site-years of flux data from ~25 AmeriFlux sites to develop biome-level statistics of surface turbulent fluxes. This includes mean annual cycles of carbon, sensible, and latent heat fluxes, normalized by energy inputs to allow for comparisons across space. Representative biome means are incorporated into a simple PBL model to evaluate potential perturbations to local air temperatures caused by changes in heat fluxes. A simple method for weighing the biogeochemical and biogeophysical benefits of terrestrial vegetation is also presented. Results suggest that, of the four scenarios investigated, afforesting grasslands to deciduous broadleaf would bring the largest climate benefits in terms of carbon sequestration and heat fluxes where water is not limiting.

  13. Quantitative evaluation of chemisorption processes on semiconductors

    Science.gov (United States)

    Rothschild, A.; Komem, Y.; Ashkenasy, N.

    2002-12-01

    This article presents a method for numerical computation of the degree of coverage of chemisorbates and the resultant surface band bending as a function of the ambient gas pressure, temperature, and semiconductor doping level. This method enables quantitative evaluation of the effect of chemisorption on the electronic properties of semiconductor surfaces, such as the work function and surface conductivity, which is of great importance for many applications such as solid- state chemical sensors and electro-optical devices. The method is applied for simulating the chemisorption behavior of oxygen on n-type CdS, a process that has been investigated extensively due to its impact on the photoconductive properties of CdS photodetectors. The simulation demonstrates that the chemisorption of adions saturates when the Fermi level becomes aligned with the chemisorption-induced surface states, limiting their coverage to a small fraction of a monolayer. The degree of coverage of chemisorbed adions is proportional to the square root of the doping level, while neutral adsorbates are independent of the doping level. It is shown that the chemisorption of neutral adsorbates behaves according to the well-known Langmuir model, regardless of the existence of charged species on the surface, while charged adions do not obey Langmuir's isotherm. In addition, it is found that in depletive chemisorption processes the resultant surface band bending increases by 2.3kT (where k is the Boltzmann constant and T is the temperature) when the gas pressure increases by one order of magnitude or when the doping level increases by two orders of magnitude.

  14. SEAM PUCKERING EVALUATION METHOD FOR SEWING PROCESS

    Directory of Open Access Journals (Sweden)

    BRAD Raluca

    2014-07-01

    Full Text Available The paper presents an automated method for the assessment and classification of puckering defects detected during the preproduction control stage of the sewing machine or product inspection. In this respect, we have presented the possible causes and remedies of the wrinkle nonconformities. Subjective factors related to the control environment and operators during the seams evaluation can be reduced using an automated system whose operation is based on image processing. Our implementation involves spectral image analysis using Fourier transform and an unsupervised neural network, the Kohonen Map, employed to classify material specimens, the input images, into five discrete degrees of quality, from grade 5 (best to grade 1 (the worst. The puckering features presented in the learning and test images have been pre-classified using the seam puckering quality standard. The network training stage will consist in presenting five input vectors (derived from the down-sampled arrays, representing the puckering grades. The puckering classification consists in providing an input vector derived from the image supposed to be classified. A scalar product between the input values vectors and the weighted training images is computed. The result will be assigned to one of the five classes of which the input image belongs. Using the Kohonen network the puckering defects were correctly classified in proportion of 71.42%.

  15. Restoration of biogeochemical function in mangrove forests

    Science.gov (United States)

    McKee, K.L.; Faulkner, P.L.

    2000-01-01

    Forest structure of mangrove restoration sites (6 and 14 years old) at two locations (Henderson Creek [HC] and Windstar [WS]) in southwest Florida differed from that of mixed-basin forests (>50 years old) with which they were once contiguous. However, the younger site (HC) was typical of natural, developing forests, whereas the older site (WS) was less well developed with low structural complexity. More stressful physicochemical conditions resulting from incomplete tidal flushing (elevated salinity) and variable topography (waterlogging) apparently affected plant survival and growth at the WS restoration site. Lower leaf fall and root production rates at the WS restoration site, compared with that at HC were partly attributable to differences in hydroedaphic conditions and structural development. However, leaf and root inputs at each restoration site were not significantly different from that in reference forests within the same physiographic setting. Macrofaunal consumption of tethered leaves also did not differ with site history, but was dramatically higher at HC compared with WS, reflecting local variation in leaf litter processing rates, primarily by snails (Melampus coffeus). Degradation of leaves and roots in mesh bags was slow overall at restoration sites, however, particularly at WS where aerobic decomposition may have been more limited. These findings indicate that local or regional factors such as salinity regime act together with site history to control primary production and turnover rates of organic matter in restoration sites. Species differences in senescent leaf nitrogen content and degradation rates further suggest that restoration sites dominated by Laguncularia racemosa and Rhizophora mangle should exhibit slower recycling of nutrients compared with natural basin forests where Avicennia germinans is more abundant. Structural development and biogeochemical functioning of restored mangrove forests thus depend on a number of factors, but site

  16. Biogeochemical cycling of radionuclides in the environment

    International Nuclear Information System (INIS)

    Livens, F.R.

    1990-01-01

    The biogeochemical cycling of radionuclides with other components such as nutrients around ecosystems is discussed. In particular the behaviour of cesium in freshwater ecosystems since the Chernobyl accident and the behaviour of technetium in the form of pertechnetate anions, TcO 4 , in marine ecosystems is considered. (UK)

  17. Manganese Oxidation by Bacteria: Biogeochemical Aspects

    Digital Repository Service at National Institute of Oceanography (India)

    Sujith, P.P.; LokaBharathi, P.A.

    to oxygen in the aquatic environment and therefore control the fate of several elements. Mn oxidizing bacteria have a suit of enzymes that not only help to scavenge Mn but also other associated elements, thus playing a crucial role in biogeochemical cycles...

  18. Indicators and Metrics for Evaluating the Sustainability of Chemical Processes

    Science.gov (United States)

    A metric-based method, called GREENSCOPE, has been developed for evaluating process sustainability. Using lab-scale information and engineering assumptions the method evaluates full-scale epresentations of processes in environmental, efficiency, energy and economic areas. The m...

  19. Preliminary economic evaluation of the Alkox process

    International Nuclear Information System (INIS)

    Silva, L.J.; Lilga, M.A.; Camaioni, D.M.; Snowden, L.J.

    1991-09-01

    A new chemical process has been invented at Battelle Pacific Northwest Laboratories for converting alkanes to alcohols. This new chemistry has been named the ''Alkox Process.'' Pacific Northwest Laboratory prepared a preliminary economic analysis for converting cyclohexane to cyclohexanol, which may be one of the most attractive applications of the Alkox process. A process flow scheme and a material balance were prepared to support rough equipment sizing and costing. The results from the economic analysis are presented in the non-proprietary section of this report. The process details, including the flow diagram and material balance, are contained in separate section of this report that is proprietary to Battelle. 7 refs., 4 tabs

  20. Biogeochemical gradients above a coal tar DNAPL

    Energy Technology Data Exchange (ETDEWEB)

    Scherr, Kerstin E., E-mail: kerstin.brandstaetter-scherr@boku.ac.at [University of Natural Resources and Life Sciences Vienna (BOKU), Department IFA-Tulln, Institute for Environmental Biotechnology, Konrad Lorenz Strasse 20, 3430 Tulln (Austria); Backes, Diana [University of Natural Resources and Life Sciences Vienna (BOKU), Department IFA-Tulln, Institute for Environmental Biotechnology, Konrad Lorenz Strasse 20, 3430 Tulln (Austria); Scarlett, Alan G. [University of Plymouth, Petroleum and Environmental Geochemistry Group, Biogeochemistry Research Centre, Drake Circus, Plymouth, Devon PL4 8AA (United Kingdom); Lantschbauer, Wolfgang [Government of Upper Austria, Directorate for Environment and Water Management, Division for Environmental Protection, Kärntner Strasse 10-12, 4021 Linz (Austria); Nahold, Manfred [GUT Gruppe Umwelt und Technik GmbH, Ingenieurbüro für Technischen Umweltschutz, Plesching 15, 4040 Linz (Austria)

    2016-09-01

    Naturally occurring distribution and attenuation processes can keep hydrocarbon emissions from dense non aqueous phase liquids (DNAPL) into the adjacent groundwater at a minimum. In a historically coal tar DNAPL-impacted site, the de facto absence of a plume sparked investigations regarding the character of natural attenuation and DNAPL resolubilization processes at the site. Steep vertical gradients of polycyclic aromatic hydrocarbons, microbial community composition, secondary water quality and redox-parameters were found to occur between the DNAPL-proximal and shallow waters. While methanogenic and mixed-electron acceptor conditions prevailed close to the DNAPL, aerobic conditions and very low dissolved contaminant concentrations were identified in three meters vertical distance from the phase. Comprehensive two-dimensional gas chromatography–mass spectrometry (GC × GC–MS) proved to be an efficient tool to characterize the behavior of the present complex contaminant mixture. Medium to low bioavailability of ferric iron and manganese oxides of aquifer samples was detected via incubation with Shewanella alga and evidence for iron and manganese reduction was collected. In contrast, 16S rDNA phylogenetic analysis revealed the absence of common iron reducing bacteria. Aerobic hydrocarbon degraders were abundant in shallow horizons, while nitrate reducers were dominating in deeper aquifer regions, in addition to a low relative abundance of methanogenic archaea. Partial Least Squares – Canonical Correspondence Analysis (PLS-CCA) suggested that nitrate and oxygen concentrations had the greatest impact on aquifer community structure in on- and offsite wells, which had a similarly high biodiversity (H’ and Chao1). Overall, slow hydrocarbon dissolution from the DNAPL appears to dominate natural attenuation processes. This site may serve as a model for developing legal and technical strategies for the treatment of DNAPL-impacted sites where contaminant plumes are

  1. Modelling benthic biophysical drivers of ecosystem structure and biogeochemical response

    Science.gov (United States)

    Stephens, Nicholas; Bruggeman, Jorn; Lessin, Gennadi; Allen, Icarus

    2016-04-01

    The fate of carbon deposited at the sea floor is ultimately decided by biophysical drivers that control the efficiency of remineralisation and timescale of carbon burial in sediments. Specifically, these drivers include bioturbation through ingestion and movement, burrow-flushing and sediment reworking, which enhance vertical particulate transport and solute diffusion. Unfortunately, these processes are rarely satisfactorily resolved in models. To address this, a benthic model that explicitly describes the vertical position of biology (e.g., habitats) and biogeochemical processes is presented that includes biological functionality and biogeochemical response capturing changes in ecosystem structure, benthic-pelagic fluxes and biodiversity on inter-annual timescales. This is demonstrated by the model's ability to reproduce temporal variability in benthic infauna, vertical pore water nutrients and pelagic-benthic solute fluxes compared to in-situ data. A key advance is the replacement of bulk parameterisation of bioturbation by explicit description of the bio-physical processes responsible. This permits direct comparison with observations and determination of key parameters in experiments. Crucially, the model resolves the two-way interaction between sediment biogeochemistry and ecology, allowing exploration of the benthic response to changing environmental conditions, the importance of infaunal functional traits in shaping benthic ecological structure and the feedback the resulting bio-physical processes exert on pore water nutrient profiles. The model is actively being used to understand shelf sea carbon cycling, the response of the benthos to climatic change, food provision and other societal benefits.

  2. A model simulation of biogeochemical conditions along the British Columbia Continental Shelf

    Science.gov (United States)

    Peña, Angelica; Fine, Isaac; Masson, Diane

    2017-04-01

    The British Columbia shelf is at the northern end of the California Current System and is influenced by summer coastal upwelling, mesoscale eddies, and freshwater inputs. A regional coupled circulation-biogeochemical (ROMS) model of this region has been developed to gain a better understanding of the potential impact of climate variability and change on lower trophic levels and the biogeochemistry of the region. A first step to address the impacts of climate variability on marine ecosystem is to develop biophysical models that simulate the present ecosystem state in relation to the climate record and can be used to examine the influence of different forcing acting, at different scales, on ecological processes. This talk will will evaluate the capability of the model to reproduce observations and to respond to main episodic events (seasonal cycle and El Niño events).

  3. Evaluation of the separation by pyrochemical processes

    International Nuclear Information System (INIS)

    2004-01-01

    This report takes stock on the studies conducted by the CEA since the years 90 in the domain of the pyrochemical process, applied to the nuclear fuels reprocessing. After a presentation of the transmutation targets and fuels, the document presents the pyrochemical processes concepts and studies. In this part the author details the process developed foreign, the studies realized at the CEA, the fuel reprocessing of the molten salts reactors and the ionic liquids at ambient temperature. (A.L.B.)

  4. Performance evaluation of coating materials and process ...

    African Journals Online (AJOL)

    austenitic stainless steel work pieces, on computer numerical controlled (CNC) lathe. Taguchi's Design of Experiments approach (DOE) is used to analyze the effect of process parameters on surface roughness to obtain their optimal setting. The analysis of variance (ANOVA) is employed to analyze the influence of process ...

  5. Microbial diversity and biogeochemical cycling in soda lakes.

    Science.gov (United States)

    Sorokin, Dimitry Y; Berben, Tom; Melton, Emily Denise; Overmars, Lex; Vavourakis, Charlotte D; Muyzer, Gerard

    2014-09-01

    Soda lakes contain high concentrations of sodium carbonates resulting in a stable elevated pH, which provide a unique habitat to a rich diversity of haloalkaliphilic bacteria and archaea. Both cultivation-dependent and -independent methods have aided the identification of key processes and genes in the microbially mediated carbon, nitrogen, and sulfur biogeochemical cycles in soda lakes. In order to survive in this extreme environment, haloalkaliphiles have developed various bioenergetic and structural adaptations to maintain pH homeostasis and intracellular osmotic pressure. The cultivation of a handful of strains has led to the isolation of a number of extremozymes, which allow the cell to perform enzymatic reactions at these extreme conditions. These enzymes potentially contribute to biotechnological applications. In addition, microbial species active in the sulfur cycle can be used for sulfur remediation purposes. Future research should combine both innovative culture methods and state-of-the-art 'meta-omic' techniques to gain a comprehensive understanding of the microbes that flourish in these extreme environments and the processes they mediate. Coupling the biogeochemical C, N, and S cycles and identifying where each process takes place on a spatial and temporal scale could unravel the interspecies relationships and thereby reveal more about the ecosystem dynamics of these enigmatic extreme environments.

  6. Multiscale Investigation on Biofilm Distribution and Its Impact on Macroscopic Biogeochemical Reaction Rates

    Science.gov (United States)

    Yan, Zhifeng; Liu, Chongxuan; Liu, Yuanyuan; Bailey, Vanessa L.

    2017-11-01

    Biofilms are critical locations for biogeochemical reactions in the subsurface environment. The occurrence and distribution of biofilms at microscale as well as their impacts on macroscopic biogeochemical reaction rates are still poorly understood. This paper investigated the formation and distributions of biofilms in heterogeneous sediments using multiscale models and evaluated the effects of biofilm heterogeneity on local and macroscopic biogeochemical reaction rates. Sediment pore structures derived from X-ray computed tomography were used to simulate the microscale flow dynamics and biofilm distribution in the sediment column. The response of biofilm formation and distribution to the variations in hydraulic and chemical properties was first examined. One representative biofilm distribution was then utilized to evaluate its effects on macroscopic reaction rates using nitrate reduction as an example. The results revealed that microorganisms primarily grew on the surfaces of grains and aggregates near preferential flow paths where both electron donor and acceptor were readily accessible, leading to the heterogeneous distribution of biofilms in the sediments. The heterogeneous biofilm distribution decreased the macroscopic rate of biogeochemical reactions as compared with those in homogeneous cases. Operationally considering the heterogeneous biofilm distribution in macroscopic reactive transport models such as using dual porosity domain concept can significantly improve the prediction of biogeochemical reaction rates. Overall, this study provided important insights into the biofilm formation and distribution in soils and sediments as well as their impacts on the macroscopic manifestation of reaction rates.

  7. Investigating the initial stages of soil formation in glacier forefields using the new biogeochemical model: SHIMMER

    Science.gov (United States)

    Bradley, James; Anesio, Alexandre; Arndt, Sandra; Sabacka, Marie; Barker, Gary; Benning, Liane; Blacker, Joshua; Singarayer, Joy; Tranter, Martyn; Yallop, Marian

    2016-04-01

    observations from chronosequences from the forefield of Midtre Lovénbreen, Svalbard (78°N), to investigate the first 120 years of soil development. We carried out an in depth analysis of the model dynamics and determined the most sensitive parameters. We then used laboratory measurements to derive values for those parameters: bacterial growth rate, growth efficiency and temperature dependency. By applying the model to the High-Arctic forefield and integrating the measured parameter values, we could refine the model and easily predict the rapid accumulation of microbial biomass that was observed in our field data. Furthermore, we show that the bacterial production is dominated by autotrophy (rather than heterotrophy). Heterotrophic production in young soils (0-20 years) is supported by labile substrate, whereas carbon stocks in older soils (60-120 years) are more refractory. Nitrogen fixing organisms are responsible for the initial accumulation of available nitrates in the soil. However, microbial processes alone do not explain the build-up of organic matter observed in the field data record. Consequently, the model infers that allochthonous deposition of organic material may play a significant contributory role that could accelerate or facilitate further microbial growth. SHIMMER provides a quantitative evaluation on the dynamics of glacier forefield systems that have previously largely been explored through qualitative interpretation of datasets. References Bradley J.A., Singarayer J.S., Anesio A.M. (2014) Microbial community dynamics in the forefield of glaciers. Proceedings Biological sciences / The Royal Society 281(1795), 2793-2802. (doi:10.1098/rspb.2014.0882). Bradley J.A., Anesio A.M., Singarayer J.S., Heath M.R., Arndt S. (2015) SHIMMER (1.0): a novel mathematical model for microbial and biogeochemical dynamics in glacier forefield ecosystems. Geosci Model Dev 8(10), 3441-3470. (doi:10.5194/gmd-8-3441-2015).

  8. A Design Process Evaluation Method for Sustainable Buildings

    OpenAIRE

    Christopher S. Magent; Sinem Korkmaz; Leidy E Klotz; David R. Riley

    2009-01-01

    This research develops a technique to model and evaluate the design process for sustainable buildings. Three case studies were conducted to validate this method. The resulting design process evaluation method for sustainable buildings (DPEMSB) may assist project teams in designing their own sustainable building design processes. This method helps to identify critical decisions in the design process, to evaluate these decisions for time and sequence, to define information required for decision...

  9. Global Change: A Biogeochemical Perspective

    Science.gov (United States)

    Mcelroy, M.

    1983-01-01

    A research program that is designed to enhance our understanding of the Earth as the support system for life is described. The program change, both natural and anthropogenic, that might affect the habitability of the planet on a time scale roughly equal to that of a human life is studied. On this time scale the atmosphere, biosphere, and upper ocean are treated as a single coupled system. The need for understanding the processes affecting the distribution of essential nutrients--carbon, nitrogen, phosphorous, sulfur, and water--within this coupled system is examined. The importance of subtle interactions among chemical, biological, and physical effects is emphasized. The specific objectives are to define the present state of the planetary life-support system; to ellucidate the underlying physical, chemical, and biological controls; and to provide the body of knowledge required to assess changes that might impact the future habitability of the Earth.

  10. Biogeochemical prospecting for uranium in Nova Scotia

    International Nuclear Information System (INIS)

    Brooks, R.R.; Holzbecher, J.; Ryan, D.E.

    1981-01-01

    Ashed twigs of Picea rubens (red spruce) collected over an area of uranium mineralization in central Nova Scotia were analyzed for uranium in the course of biogeochemical prospecting for this element. Uranium levels in background samples were significantly lower than in those collected from areas with mineralization either at depth or on the surface. Scintillometric data were useful only to differentiate background and surface mineralization. Uranium levels in soils showed no correlation whatsoever with mineralization or with radiometry. There was a very high degree of correlation between the scintillometric data and uranium concentrations in ashed twigs and it is considered that twigs of Picea rubens might be successfully used for biogeochemical prospecting for uranium in this area. (Auth.)

  11. Tracking permafrost soil degradation through sulphur biogeochemical tracers

    Science.gov (United States)

    Canario, João; Santos, Margarida C.; Vieira, Gonçalo; Vincent, Warwick F.

    2017-04-01

    Rising temperatures are contributing to the rapid degradation of Arctic permafrost soils. Several studies have been using some biogeochemical tracers as indicators of the organic matter degradation although fewer attention has been given to sulphur. In fact, the chemistry of this element is of environmental importance because it plays a key role in the degradation of natural organic matter and influences the partitioning, speciation and fate of other trace elements. To better understand the role of sulphur in biogeochemical processes in permafrost soils several campaigns were undertaken in the Canadian subarctic region of Kuujjuarapik-Whapmagoostui and Umiujaq (QC) as a part of the Canadian ADAPT and the Portuguese PERMACHEM projects. In four sites along those regions soil samples were collected and pore water were extracted. Dissolved sulphur compounds (sulphide and sulphate) were determined in water samples while in soils particulate sulphides, pyrite and elemental sulphur were quantified by voltammetry. Organic sulphur compounds were identified using 33SssNMR and X-ray diffraction both in powder and single crystal analysis were used to identify crystalline sulphides. Finally, subsamples of soils and water samples were analysed for total particulate and dissolved organic carbon. The results showed that sulphur composition depends largely on the origin of permafrost soils. In soils originated from organic-rich palsas, the proportion of organic sulphur (% of the total) is higher than 50%, while in mineral lithalsa soils the opposite was found. In both cases the origin of sulphur was mainly from plant organic matter degradation. The combined structural and chemical analysis allowed the identified different stages of soil degradation by determined the ratio between inorganic and organic sulphur species and by following the different NMR and XRD spectra. These preliminary results pointed to the importance of the sulphur biogeochemistry in permafrost soils and provide

  12. Evaluation of pretreatment processes for supercritical water oxidation

    International Nuclear Information System (INIS)

    Barnes, C.M.

    1994-01-01

    This report evaluates processes to chemically treat US Department of Energy wastes to remove organic halogens, phosphorus, and sulfur. Chemical equilibrium calculations, process simulations, and responses from developers and licensors form the basis for comparisons. Gas-phase catalytic hydrogenation processes, strong base and base catalyzed processes, high pressure hydrolysis, and other emerging or commercial dehalogenation processes (both liquid and mixed phase) were considered. Cost estimates for full-scale processes and demonstration testing are given. Based on the evaluation, testing of a hydrogenation process and a strong base process are recommended

  13. Evaluation of pretreatment processes for supercritical water oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Barnes, C.M.

    1994-01-01

    This report evaluates processes to chemically treat US Department of Energy wastes to remove organic halogens, phosphorus, and sulfur. Chemical equilibrium calculations, process simulations, and responses from developers and licensors form the basis for comparisons. Gas-phase catalytic hydrogenation processes, strong base and base catalyzed processes, high pressure hydrolysis, and other emerging or commercial dehalogenation processes (both liquid and mixed phase) were considered. Cost estimates for full-scale processes and demonstration testing are given. Based on the evaluation, testing of a hydrogenation process and a strong base process are recommended.

  14. An Empirical Examination and Metaevaluation of the Impact Evaluation Process

    Science.gov (United States)

    Blake, Anne M.

    2013-01-01

    This dissertation empirically examines the Guerra-Lopez (2007a) Impact Evaluation Process (IEP), which is a prescriptive program evaluation model. Since there is no generally accepted process for arriving at final judgments about the usefulness, appropriateness, effectiveness, reliability, and validity of evaluation models, this study used a…

  15. Converting copepod vital rates into units appropriate for biogeochemical models

    Science.gov (United States)

    Frangoulis, C.; Carlotti, F.; Eisenhauer, L.; Zervoudaki, S.

    2010-01-01

    The conversion of units is one of the difficulties of model parameterisation. Conversion errors may result not only from incorrect choices of conversion factors, but also from incorrect choices of the value itself. In biogeochemical models, mesozooplankton, is the highest trophic level of the food web, and it is very often reduced to a single variable generally considered as a representation of the copepod community, the dominant taxa in mesozooplankton. If this simplifies the information to be obtained for the stock, a correct parameterisation of the processes related to the copepod community is already a tricky task due to the wide range of copepod species, sizes, stages and behaviour. The goal of this paper is to improve the communication between experimentalists and modellers by giving indications for the conversion of copepod vital rates from experimental to biogeochemical model units. This includes the choice of values, conversion factors, terminology distinction and the scale transfer. To begin with, we briefly address the common problem of the conversion of a rate per individual to a rate per mass. Then, we focus on unit conversion problems for each specific rate and give recommendations. Finally, we discuss the problem of scale transfer between the level of organisation at which the rate value is measured at characteristic time and space-scales versus the level of representation of the corresponding process in the model, with its different characteristic time and space-scales .

  16. Biogeochemical ecology of aquaculture ponds

    International Nuclear Information System (INIS)

    Weisburd, R.S.J.

    1988-01-01

    Two methods to determine rates of organic matter production and consumption were applied in shrimp aquaculture ponds. Several questions were posed: can net rates of organic matter production and consumption be determined accurately through application of dissolved inorganic carbon (DIC) mass balance in a pond with high advective through-put? Are organically loaded aquaculture ponds autotrophic? How do rates of organic production vary temporally? Are there diurnal changes in respiration rates? Four marine ponds in Hawaii have been evaluated for a 53 day period through the use of geochemical mass balances. All fluxes of DIC into and out of the ponds were considered. DIC was calculated from hourly pH measurements and weekly alkalinity measurements. Average uptake of DIC from the pond water, equivalent to net community production, revealed net autotrophy in all cases. Hourly and longer period variations in organic matter production rates were examined. The daily cycle dominated the variation in rates of net community production. Maximal rates of net community production were maintained for four to six hours starting in mid-morning. Respiration rates decreased rapidly during the night in two of the ponds and remained essentially constant in the others. A similar pattern of decreasing respiration at night was seen in freshwater shrimp ponds which were studied with incubations. A new method involving isotope dilution of 14 C-labeled DIC was used to measure respiration rates in light and dark bottles. This method is an inexpensive and convenient procedure which should also be useful in other environments. The incubations demonstrated that plankton respiration rates peak at or soon after solar noon and vary over the course of the day by about a factor of two

  17. Tracking Water, C, N, and P by Linking Local Scale Soil Hydrologic and Biogeochemical Features to Watershed Scale

    Science.gov (United States)

    Sedaghatdoost, A.; Mohanty, B.; Huang, Y.

    2017-12-01

    The biogeochemical cycles of carbon (C), nitrogen (N), and phosphorus (P) have many contemporary significance due to their critical roles in determining the structure and function of ecosystems. The objectives of our study is to find out temporal dynamics and spatial distribution of soil physical, chemical, and biological properties and their interaction with C, N, and P cycles in the soil for different land covers and weather conditions. The study is being conducted at three locations within Texas Water Observatory (TWO), including Riesel (USDA-ARS experimental watersheds), Texas A&M Agrilife Research Farm, and Danciger forest in Texas. Soil physical, hydraulic, chemical (total C, total N, total P, pH, EC, redox potential, N-NO3-, N-NH4+, PO42-, K, Ca, Mg, Na, Mn, and Alox and Feox), and microbiological (Microbial biomass C, N, and P, PLFA analysis, enzymatic activity) properties are being measured in the top 30 cm of the soil profile. Our preliminary data shows that biogeochemical processes would be more profound in the areas with higher temperature and precipitation as these factors stimulate microbial activity and thus influence C, N, and P cycles. Also concentrations of C and N are greater in woodlands relative to remnant grasslands as a consequence of the greater above- and below-ground productivity of woodlands relative to remnant grasslands. We hypothesize that finer soil textures have more organic matter, microbial population, and reactive surfaces for chemicals than coarse soils, as described in some recent literature. However, the microbial activity may not be active in fine textured soils as organic materials may be sorbed to clay surfaces or protected from decomposing organisms. We also expect reduced condition in saturated soils which will decrease carbon mineralization while increase denitrification and alkalinity in the soil. Spatio-temporal data with initial evaluation of biogeochemical factors/processes for different land covers will be presented.

  18. PERFORMANCE EVALUATION OF A DRYER FOR PROCESSED ...

    African Journals Online (AJOL)

    thinkexploitsint'l

    ABSTRACT. Drying of fresh fermented locust beans condiments is highly important in marketing strategy. Performance test of the dryer for processed locust beans condiments (Iru) was carried out using an instrumented dryer designed and developed, this was used to dry two varieties of fermented locust beans (Iru Woro of ...

  19. Evaluation of thermostable enzymes for bioethanol processing

    DEFF Research Database (Denmark)

    Skovgaard, Pernille Anastasia

    8). It was possible to recover more thermostable activity after distillation meaning that the nzymes could be recycled more efficiently resulting in a net savings of enzymes used. By testing different enzyme cocktails through the bioethanol process, specially during liquefaction and distillation...

  20. Evaluation of interaction dynamics of concurrent processes

    Science.gov (United States)

    Sobecki, Piotr; Białasiewicz, Jan T.; Gross, Nicholas

    2017-03-01

    The purpose of this paper is to present the wavelet tools that enable the detection of temporal interactions of concurrent processes. In particular, the determination of interaction coherence of time-varying signals is achieved using a complex continuous wavelet transform. This paper has used electrocardiogram (ECG) and seismocardiogram (SCG) data set to show multiple continuous wavelet analysis techniques based on Morlet wavelet transform. MATLAB Graphical User Interface (GUI), developed in the reported research to assist in quick and simple data analysis, is presented. These software tools can discover the interaction dynamics of time-varying signals, hence they can reveal their correlation in phase and amplitude, as well as their non-linear interconnections. The user-friendly MATLAB GUI enables effective use of the developed software what enables to load two processes under investigation, make choice of the required processing parameters, and then perform the analysis. The software developed is a useful tool for researchers who have a need for investigation of interaction dynamics of concurrent processes.

  1. Inverse modeling of pan-Arctic methane emissions at high spatial resolution: what can we learn from assimilating satellite retrievals and using different process-based wetland and lake biogeochemical models?

    Directory of Open Access Journals (Sweden)

    Z. Tan

    2016-10-01

    Full Text Available Understanding methane emissions from the Arctic, a fast-warming carbon reservoir, is important for projecting future changes in the global methane cycle. Here we optimized methane emissions from north of 60° N (pan-Arctic regions using a nested-grid high-resolution inverse model that assimilates both high-precision surface measurements and column-average SCanning Imaging Absorption spectroMeter for Atmospheric CHartogrphY (SCIAMACHY satellite retrievals of methane mole fraction. For the first time, methane emissions from lakes were integrated into an atmospheric transport and inversion estimate, together with prior wetland emissions estimated with six biogeochemical models. In our estimates, in 2005, global methane emissions were in the range of 496.4–511.5 Tg yr−1, and pan-Arctic methane emissions were in the range of 11.9–28.5 Tg yr−1. Methane emissions from pan-Arctic wetlands and lakes were 5.5–14.2 and 2.4–14.2 Tg yr−1, respectively. Methane emissions from Siberian wetlands and lakes are the largest and also have the largest uncertainty. Our results indicate that the uncertainty introduced by different wetland models could be much larger than the uncertainty of each inversion. We also show that assimilating satellite retrievals can reduce the uncertainty of the nested-grid inversions. The significance of lake emissions cannot be identified across the pan-Arctic by high-resolution inversions, but it is possible to identify high lake emissions from some specific regions. In contrast to global inversions, high-resolution nested-grid inversions perform better in estimating near-surface methane concentrations.

  2. Elemental and isotopic imaging to study biogeochemical functioning of intact soil micro-environments

    Science.gov (United States)

    Mueller, Carsten W.

    2017-04-01

    The complexity of soils extends from the ecosystem-scale to individual micro-aggregates, where nano-scale interactions between biota, organic matter (OM) and mineral particles are thought to control the long-term fate of soil carbon and nitrogen. It is known that such biogeochemical processes show disproportionally high reaction rates within nano- to micro-meter sized isolated zones ('hot spots') in comparison to surrounding areas. However, the majority of soil research is conducted on large bulk (> 1 g) samples, which are often significantly altered prior to analysis and analysed destructively. Thus it has previously been impossible to study elemental flows (e.g. C and N) between plants, microbes and soil in complex environments at the necessary spatial resolution within an intact soil system. By using nano-scale secondary ion mass spectrometry (NanoSIMS) in concert with other imaging techniques (e.g. scanning electron microscopy (SEM) and micro computed tomography (µCT)), classic analyses (isotopic and elemental analysis) and biochemical methods (e.g. GC-MS) it is possible to exhibit a more complete picture of soil processes at the micro-scale. I will present exemplarily results about the fate and distribution of organic C and N in complex micro-scale soil structures for a range of intact soil systems. Elemental imaging was used to study initial soil formation as an increase in the structural connectivity of micro-aggregates. Element distribution will be presented as a key to detect functional spatial patterns and biogeochemical hot spots in macro-aggregate functioning and development. In addition isotopic imaging will be demonstrated as a key to trace the fate of plant derived OM in the intact rhizosphere from the root to microbiota and mineral soil particles. Especially the use of stable isotope enrichment (e.g. 13CO2, 15NH4+) in conjunction with NanoSIMS allows to directly trace the fate of OM or nutrients in soils at the relevant scale (e.g. assimilate C

  3. Biogeochemical C and N cycles in urban soils.

    Science.gov (United States)

    Lorenz, Klaus; Lal, Rattan

    2009-01-01

    The percentage of urban population is projected to increase drastically. In 2030, 50.7 to 86.7% of the total population in Africa and Northern America may live in urban areas, respectively. The effects of the attendant increases in urban land uses on biogeochemical C and N cycles are, however, largely unknown. Biogeochemical cycles in urban ecosystems are altered directly and indirectly by human activities. Direct effects include changes in the biological, chemical and physical soil properties and processes in urban soils. Indirect effects of urban environments on biogeochemical cycles may be attributed to the introductions of exotic plant and animal species and atmospheric deposition of pollutants. Urbanization may also affect the regional and global atmospheric climate by the urban heat island and pollution island effect. On the other hand, urban soils have the potential to store large amounts of soil organic carbon (SOC) and, thus, contribute to mitigating increases in atmospheric CO(2) concentrations. However, the amount of SOC stored in urban soils is highly variable in space and time, and depends among others on soil parent material and land use. The SOC pool in 0.3-m depth may range between 16 and 232 Mg ha(-1), and between 15 and 285 Mg ha(-1) in 1-m depth. Thus, depending on the soil replaced or disturbed, urban soils may have higher or lower SOC pools, but very little is known. This review provides an overview of the biogeochemical cycling of C and N in urban soils, with a focus on the effects of urban land use and management on soil organic matter (SOM). In view of the increase in atmospheric CO(2) and reactive N concentrations as a result of urbanization, urban land use planning must also include strategies to sequester C in soil, and also enhance the N sink in urban soils and vegetation. This will strengthen soil ecological functions such as retention of nutrients, hazardous compounds and water, and also improve urban ecosystem services by promoting

  4. Molecular biogeochemical provinces in the Atlantic Surface Ocean

    Science.gov (United States)

    Koch, B. P.; Flerus, R.; Schmitt-Kopplin, P.; Lechtenfeld, O. J.; Bracher, A.; Cooper, W.; Frka, S.; Gašparović, B.; Gonsior, M.; Hertkorn, N.; Jaffe, R.; Jenkins, A.; Kuss, J.; Lara, R. J.; Lucio, M.; McCallister, S. L.; Neogi, S. B.; Pohl, C.; Roettgers, R.; Rohardt, G.; Schmitt, B. B.; Stuart, A.; Theis, A.; Ying, W.; Witt, M.; Xie, Z.; Yamashita, Y.; Zhang, L.; Zhu, Z. Y.; Kattner, G.

    2010-12-01

    One of the most important aspects to understand marine organic carbon fluxes is to resolve the molecular mechanisms which convert fresh, labile biomolecules into semi-labile and refractory dissolved and particulate organic compounds in the ocean. In this interdisciplinary project, which was performed on a cruise with RV Polarstern, we carried out a detailed molecular characterisation of dissolved organic matter (DOM) on a North-South transect in the Atlantic surface ocean in order to relate the data to different biological, climatic, oceanographic, and meteorological regimes as well as to terrestrial input from riverine and atmospheric sources. Our goal was to achieve a high resolution data set for the biogeochemical characterisation of the sources and reactivity of DOM. We applied ultrahigh resolution Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR-MS), nutrient, trace element, amino acid, and lipid analyses and other biogeochemical measurements for 220 samples from the upper water column (0-200m) and eight deep profiles. Various spectroscopic techniques were applied continuously in a constant sample water flow supplied by a fish system and the moon pool. Radiocarbon dating enabled assessing DOC residence time. Bacterial abundance and production provided a metabolic context for the DOM characterization work and pCO2 concentrations. Combining molecular organic techniques and inductively coupled plasma mass spectrometry (ICP-MS) established an important link between organic and inorganic biogeochemical studies. Multivariate statistics, primarily based on FT-ICR-MS data for 220 samples, allowed identifying geographical clusters which matched ecological provinces proposed previously by Longhurst (2007). Our study demonstrated that marine DOM carries molecular information reflecting the “history” of ocean water masses. This information can be used to define molecular biogeochemical provinces and to improve our understanding of element fluxes in

  5. Coal liquefaction process streams characterization and evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Robbins, G.A.; Brandes, S.D.; Winschel, R.A.; Burke, F.P.

    1992-08-01

    This is the tenth Quarterly Technical Progress Report under DOE Contract DE-AC22-89PC89883. Process oils from Wilsonville Run 262 were analyzed to provide information on process performance. Run 262 was operated from July 10 through September 30, 1991, in the thermal/catalytic Close-Coupled Integrated Two-Stage Liquefaction (CC-ITSL) configuration with ash recycle. The feed coal was Black Thunder Mine subbituminous coal. The high/low temperature sequence was used. Each reactor was operated at 50% of the available reactor volume. The interstage separator was in use throughout the run. The second-stage reactor was charged with aged Criterion 324 catalyst (Ni/Mo on 1/16 inch alumina extrudate support). Slurry catalysts and sulfiding agent were fed to the first-stage reactor. Molyvan L is an organometallic compound which contains 8.1% Mo, and is commercially available as an oil-soluble lubricant additive. It was used in Run 262 as a dispersed hydrogenation catalyst precursor, primarily to alleviate deposition problems which plagued past runs with Black Thunder coal. One test was made with little supported catalyst in the second stage. The role of phenolic groups in donor solvent properties was examined. In this study, four samples from direct liquefaction process oils were subjected to O-methylation of the phenolic groups, followed by chemical analysis and solvent quality testing.

  6. Seismic re-evaluation process in Medzamor-2 NPP

    International Nuclear Information System (INIS)

    Zadoyan, P.

    2000-01-01

    Seismic re-evaluation process for Medzamor-2 NPP describes the following topics: program implementation status; re-evaluation program structure; regulatory procedure and review plan; current tasks and practice; and regulatory assessment and research programs

  7. Characterization of mixing errors in a coupled physical biogeochemical model of the North Atlantic: implications for nonlinear estimation using Gaussian anamorphosis

    Directory of Open Access Journals (Sweden)

    D. Béal

    2010-02-01

    Full Text Available In biogeochemical models coupled to ocean circulation models, vertical mixing is an important physical process which governs the nutrient supply and the plankton residence in the euphotic layer. However, vertical mixing is often poorly represented in numerical simulations because of approximate parameterizations of sub-grid scale turbulence, wind forcing errors and other mis-represented processes such as restratification by mesoscale eddies. Getting a sufficient knowledge of the nature and structure of these errors is necessary to implement appropriate data assimilation methods and to evaluate if they can be controlled by a given observation system.

    In this paper, Monte Carlo simulations are conducted to study mixing errors induced by approximate wind forcings in a three-dimensional coupled physical-biogeochemical model of the North Atlantic with a 1/4° horizontal resolution. An ensemble forecast involving 200 members is performed during the 1998 spring bloom, by prescribing perturbations of the wind forcing to generate mixing errors. The biogeochemical response is shown to be rather complex because of nonlinearities and threshold effects in the coupled model. The response of the surface phytoplankton depends on the region of interest and is particularly sensitive to the local stratification. In addition, the statistical relationships computed between the various physical and biogeochemical variables reflect the signature of the non-Gaussian behaviour of the system. It is shown that significant information on the ecosystem can be retrieved from observations of chlorophyll concentration or sea surface temperature if a simple nonlinear change of variables (anamorphosis is performed by mapping separately and locally the ensemble percentiles of the distributions of each state variable on the Gaussian percentiles. The results of idealized observational updates (performed with perfect observations and neglecting horizontal correlations

  8. Evaluation of thermostable enzymes for bioethanol processing

    DEFF Research Database (Denmark)

    Skovgaard, Pernille Anastasia

    . Enzymes are added to the bioethanol process after pretreatment. For an efficient sugar and ethanol yield, the solids content of biomass is normally increased, which results in highly viscous slurries that are difficult to mix. Therefore, the first enzymatic challenge is to ensure rapid reduction...... content trough liquefaction and SSF, the cellulase and xylanase activity remained at 80% of the initial value. During distillation, the thermostable enzymes were more temperature and ethanol tolerant compared to mesophilic enzymes (chapter 7). For both mixtures it was seen that an increasing ethanol...

  9. A Design Process Evaluation Method for Sustainable Buildings

    Directory of Open Access Journals (Sweden)

    Christopher S. Magent

    2009-12-01

    Full Text Available This research develops a technique to model and evaluate the design process for sustainable buildings. Three case studies were conducted to validate this method. The resulting design process evaluation method for sustainable buildings (DPEMSB may assist project teams in designing their own sustainable building design processes. This method helps to identify critical decisions in the design process, to evaluate these decisions for time and sequence, to define information required for decisions from various project stakeholders, and to identify stakeholder competencies for process implementation. Published in the Journal AEDM - Volume 5, Numbers 1-2, 2009 , pp. 62-74(13

  10. Communication processes, public administration and performance evaluation

    Directory of Open Access Journals (Sweden)

    Arta Musaraj

    2011-01-01

    In order to shed further light for our readers, we analyze by emphasizing the significant differences between the civil law and common law system on one side and the legal families that are part of the same legal system, either “Civil” or “Common,” on the other side. The Europeanization of law refers to the communization of the law by EU institutions and to a process that aims at creating a common Europe legal system. In the end, either in medium or long term, the Europeanization is contributing to the so-called non-mandatory or soft harmonization of private law. It is in the best interest of the EU to seek adequate judicial instruments to accommodate the massive numbers of laws deriving from different Civil Law and the Common law systems.

  11. Supplier Evaluation Process by Pairwise Comparisons

    Directory of Open Access Journals (Sweden)

    Arkadiusz Kawa

    2015-01-01

    Full Text Available We propose to assess suppliers by using consistency-driven pairwise comparisons for tangible and intangible criteria. The tangible criteria are simpler to compare (e.g., the price of a service is lower than that of another service with identical characteristics. Intangible criteria are more difficult to assess. The proposed model combines assessments of both types of criteria. The main contribution of this paper is the presentation of an extension framework for the selection of suppliers in a procurement process. The final weights are computed from relative pairwise comparisons. For the needs of the paper, surveys were conducted among Polish managers dealing with cooperation with suppliers in their enterprises. The Polish practice and restricted bidding are discussed, too.

  12. Redox-induced mobilization of copper, selenium, and zinc in deltaic soils originating from Mississippi (U.S.A.) and Nile (Egypt) River Deltas: A better understanding of biogeochemical processes for safe environmental management.

    Science.gov (United States)

    Shaheen, Sabry M; Frohne, Tina; White, John R; DeLaune, Ron D; Rinklebe, Jörg

    2017-01-15

    Studies about the mobilization of potentially toxic elements (PTEs) in deltaic soils can be challenging, provide critical information on assessing the potential risk and fate of these elements and for sustainable management of these soils. The impact of redox potential (E H ), pH, iron (Fe), manganese (Mn), sulfate (SO 4 2- ), chloride (Cl - ), aliphatic dissolved organic carbon (DOC), and aromatic dissolved organic carbon (DAC) on the mobilization of copper (Cu), selenium (Se), and zinc (Zn) was studied in two soils collected from the Nile and Mississippi Rivers deltaic plains focused on increasing our understanding of the fate of these toxic elements. Soils were exposed to a range of redox conditions stepwise from reducing to oxidizing soil conditions using an automated biogeochemical microcosm apparatus. Concentrations of DOC and Fe were high under reducing conditions as compared to oxidizing conditions in both soils. The proportion of DAC in relation to DOC in solution (aromaticity) was high in the Nile Delta soil (NDS) and low in the Mississippi Delta soil (MDS) under oxidizing conditions. Mobilization of Cu was low under reducing conditions in both soils which was likely caused by sulfide precipitation and as a result of reduction of Cu 2+ to Cu 1+ . Mobilization of Se was high under low E H in both soils. Release of Se was positively correlated with DOC, Fe, Mn, and SO 4 2- in the NDS, and with Fe in the MDS. Mobilization of Zn showed negative correlations with E H and pH in the NDS while these correlations were non-significant in the MDS. The release dynamics of dissolved Zn could be governed mainly by the chemistry of Fe and Mn in the NDS and by the chemistry of Mn in the MDS. Our findings suggest that a release of Se and Zn occurs under anaerobic conditions, while aerobic conditions favor the release of Cu in both soils. In conclusion, the release of Cu, Se, and Zn under different reducing and oxidizing conditions in deltaic wetland soils should be taken

  13. A Coupled Ocean General Circulation, Biogeochemical, and Radiative Model of the Global Oceans: Seasonal Distributions of Ocean Chlorophyll and Nutrients

    Science.gov (United States)

    Gregg, Watson W.; Busalacchi, Antonio (Technical Monitor)

    2000-01-01

    A coupled ocean general circulation, biogeochemical, and radiative model was constructed to evaluate and understand the nature of seasonal variability of chlorophyll and nutrients in the global oceans. Biogeochemical processes in the model are determined from the influences of circulation and turbulence dynamics, irradiance availability. and the interactions among three functional phytoplankton groups (diatoms. chlorophytes, and picoplankton) and three nutrients (nitrate, ammonium, and silicate). Basin scale (greater than 1000 km) model chlorophyll results are in overall agreement with CZCS pigments in many global regions. Seasonal variability observed in the CZCS is also represented in the model. Synoptic scale (100-1000 km) comparisons of imagery are generally in conformance although occasional departures are apparent. Model nitrate distributions agree with in situ data, including seasonal dynamics, except for the equatorial Atlantic. The overall agreement of the model with satellite and in situ data sources indicates that the model dynamics offer a reasonably realistic simulation of phytoplankton and nutrient dynamics on synoptic scales. This is especially true given that initial conditions are homogenous chlorophyll fields. The success of the model in producing a reasonable representation of chlorophyll and nutrient distributions and seasonal variability in the global oceans is attributed to the application of a generalized, processes-driven approach as opposed to regional parameterization and the existence of multiple phytoplankton groups with different physiological and physical properties. These factors enable the model to simultaneously represent many aspects of the great diversity of physical, biological, chemical, and radiative environments encountered in the global oceans.

  14. EVALUATION OF PRODUCT DEVELOPMENT PROCESS USING EMVS

    Directory of Open Access Journals (Sweden)

    Iara Tonissi Moroni Cutovoi

    2014-12-01

    Full Text Available This paper evaluates a PDP model application in an auto parts company, leader in its segment. From the application of lean thinking in the supply chain and the EMVS performance analysis methodology for PDP, a check list is created to avoid waste in project management. In this paper, we show that EMVS can be positively impacted through active management of knowledge within a project. This paper suggests that the value-enabling portion of a project manager's role requires aligning knowledge across these three key domains regarding PDP Gates (Phases at company manufacturers of auto parts, Lean Thinking and Value Stream, and methodology for managing projects through performance-term rates and costs. The results show that the methodology has positive aspects, but its implementation takes time and has repercussions throughout the supply chain. Further this research try to explain the types of wastes and view of new products' development is enhanced and associates a manufacturing strategy focus on EMVS performance analysis and lean thinking, PDP and value stream mapping  showing the important of contribution this tools at reduction of waste.

  15. EVALUATION OF ALTERNATIVE STRONIUM AND TRANSURANIC SEPARATION PROCESSES

    Energy Technology Data Exchange (ETDEWEB)

    SMALLEY CS

    2011-04-25

    In order to meet contract requirements on the concentrations of strontium-90 and transuranic isotopes in the immobilized low-activity waste, strontium-90 and transuranics must be removed from the supernate of tanks 241-AN-102 and 241-AN-107. The process currently proposed for this application is an in-tank precipitation process using strontium nitrate and sodium permanganate. Development work on the process has not proceeded since 2005. The purpose of the evaluation is to identify whether any promising alternative processes have been developed since this issue was last examined, evaluate the alternatives and the baseline process, and recommend which process should be carried forward.

  16. Quality evaluation of blood irradiation process

    International Nuclear Information System (INIS)

    Goto, R.E.; Medeiros, R.B.

    2009-01-01

    An adverse reaction in blood transfusion is the graft versus host disease (GVHD). This disease affects immunodeficient or immunosuppressed patients where transfused T cells proliferate and initiate a host's immune system reaction. Blood gamma irradiation is the most efficient way to inhibit lymphocyte T blastic transformation and mitotic activity and it is the most effective method to combat this disorder. However, there is no fast and effective system to analyze the dose distribution in the irradiation process and guarantee that the absorbed doses are in agreement with FDA recommendations. This study aims to establish a periodic quality control of the gammacell irradiators using radiochromic films properly calibrated. The quality control is simply and effective to combat GVHD as well as is useful to detect mechanical fails at rotation set system through the dose uniformity analysis. It was possible to verify the uniformity ranged from -72.38% to 106.33% and some blood bag received doses not compatible with recommended international threshold. (author)

  17. Coal liquefaction process streams characterization and evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Brandes, S.D.; Lancet, M.S.; Robbins, G.A.; Winschel, R.A.; Burke, F.P.

    1992-11-01

    This is the eleventh Quarterly Technical Progress Report under DOE Contract DE-AC22-89PC89883. Major topics reported are: (1) The results of a study designed to determine the effects of the conditions employed at the Wilsonville slurry preheater vessel on coal conversion is described. (2) Stable carbon isotope ratios were determined and used to source the carbon of three product samples from Period 49 of UOP bench-scale coprocessing Run 37. The results from this coprocessing run agree with the general trends observed in other coprocessing runs that we have studied. (3) Microautoclave tests and chemical analyses were performed to calibrate'' the reactivity of the standard coal used for determining donor solvent quality of process oils in this contract. (4) Several aspects of Wilsonville Close-Coupled Integrated Two-Stage Liquefaction (CC-ITSL) resid conversion kinetics were investigated; results are presented. Error limits associated with calculations of deactivation rate constants previously reported for Runs 258 and 261 are revised and discussed. A new procedure is described that relates the conversions of 850[degrees]F[sup +] , 1050[degrees]F[sup +], and 850 [times] 1050[degrees]F material. Resid conversions and kinetic constants previously reported for Run 260 were incorrect; corrected data and discussion are found in Appendix I of this report.

  18. Parameter estimation and uncertainty quantification in a biogeochemical model using optimal experimental design methods

    Science.gov (United States)

    Reimer, Joscha; Piwonski, Jaroslaw; Slawig, Thomas

    2016-04-01

    The statistical significance of any model-data comparison strongly depends on the quality of the used data and the criterion used to measure the model-to-data misfit. The statistical properties (such as mean values, variances and covariances) of the data should be taken into account by choosing a criterion as, e.g., ordinary, weighted or generalized least squares. Moreover, the criterion can be restricted onto regions or model quantities which are of special interest. This choice influences the quality of the model output (also for not measured quantities) and the results of a parameter estimation or optimization process. We have estimated the parameters of a three-dimensional and time-dependent marine biogeochemical model describing the phosphorus cycle in the ocean. For this purpose, we have developed a statistical model for measurements of phosphate and dissolved organic phosphorus. This statistical model includes variances and correlations varying with time and location of the measurements. We compared the obtained estimations of model output and parameters for different criteria. Another question is if (and which) further measurements would increase the model's quality at all. Using experimental design criteria, the information content of measurements can be quantified. This may refer to the uncertainty in unknown model parameters as well as the uncertainty regarding which model is closer to reality. By (another) optimization, optimal measurement properties such as locations, time instants and quantities to be measured can be identified. We have optimized such properties for additional measurement for the parameter estimation of the marine biogeochemical model. For this purpose, we have quantified the uncertainty in the optimal model parameters and the model output itself regarding the uncertainty in the measurement data using the (Fisher) information matrix. Furthermore, we have calculated the uncertainty reduction by additional measurements depending on time

  19. Numerical modeling of watershed-scale radiocesium transport coupled with biogeochemical cycling in forests

    Science.gov (United States)

    Mori, K.; Tada, K.; Tawara, Y.; Tosaka, H.; Ohno, K.; Asami, M.; Kosaka, K.

    2015-12-01

    Since the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident, intensive monitoring and modeling works on radionuclide transfer in environment have been carried out. Although Cesium (Cs) concentration has been attenuating due to both physical and environmental half-life (i.e., wash-off by water and sediment), the attenuation rate depends clearly on the type of land use and land cover. In the Fukushima case, studying the migration in forest land use is important for predicting the long-term behavior of Cs because most of the contaminated region is covered by forests. Atmospheric fallout is characterized by complicated behavior in biogeochemical cycle in forests which can be described by biotic/abiotic interactions between many components. In developing conceptual and mathematical model on Cs transfer in forest ecosystem, defining the dominant components and their interactions are crucial issues (BIOMASS, 1997-2001). However, the modeling of fate and transport in geosphere after Cs exports from the forest ecosystem is often ignored. An integrated watershed modeling for simulating spatiotemporal redistribution of Cs that includes the entire region from source to mouth and surface to subsurface, has been recently developed. Since the deposited Cs can migrate due to water and sediment movement, the different species (i.e., dissolved and suspended) and their interactions are key issues in the modeling. However, the initial inventory as source-term was simplified to be homogeneous and time-independent, and biogeochemical cycle in forests was not explicitly considered. Consequently, it was difficult to evaluate the regionally-inherent characteristics which differ according to land uses, even if the model was well calibrated. In this study, we combine the different advantages in modeling of forest ecosystem and watershed. This enable to include more realistic Cs deposition and time series of inventory can be forced over the land surface. These processes are integrated

  20. Biogeochemical research priorities for sustainable biofuel and bioenergy feedstock production in the Americas

    Science.gov (United States)

    Hero T. Gollany; Brian D. Titus; D. Andrew Scott; Heidi Asbjornsen; Sigrid C. Resh; Rodney A. Chimner; Donald J. Kaczmarek; Luiz F.C. Leite; Ana C.C. Ferreira; Kenton A. Rod; Jorge Hilbert; Marcelo V. Galdos; Michelle E. Cisz

    2015-01-01

    Rapid expansion in biomass production for biofuels and bioenergy in the Americas is increasing demand on the ecosystem resources required to sustain soil and site productivity. We review the current state of knowledge and highlight gaps in research on biogeochemical processes and ecosystem sustainability related to biomass production. Biomass production systems...

  1. Contrasting biogeochemical cycles of cobalt in the surface western Atlantic Ocean

    NARCIS (Netherlands)

    Dulaquais, Gabriel; Boye, Marie; Middag, Rob; Owens, Stephanis; Puigcorbe, Viena; Buesseler, Ken; Masque, Pere; Carton, Xavier; de Baar, Henricus

    2014-01-01

    Dissolved cobalt (DCo; 0.2 mu m; 10%) to the DCo stock of the mixed layer in the equatorial and north subtropical domains. Biotic and abiotic processes as well as the physical terms involved in the biogeochemical cycle of Co were defined and estimated. This allowed establishing the first global

  2. Process evaluation results from the HEALTHY physical education intervention

    Science.gov (United States)

    Process evaluation is an assessment of the implementation of an intervention. A process evaluation component was embedded in the HEALTHY study, a primary prevention trial for Type 2 diabetes implemented over 3 years in 21 middle schools across the United States. The HEALTHY physical education (PE) i...

  3. Performance Evaluation of a Dryer for Processed Locust Bean ...

    African Journals Online (AJOL)

    Performance Evaluation of a Dryer for Processed Locust Bean Condiments. ... parameters on the drying rates of the dried processed products. These results showed a significant difference in the different varieties dried at 5% confidence level. Keywords: Performance Evaluation, Efficiency, Drying Rates, Iru Woro, Iru Pete ...

  4. Evaluation and Modification of Processes for Bioethanol Separation and Production

    Directory of Open Access Journals (Sweden)

    Johnner P Sitompul

    2012-04-01

    Full Text Available This paper concerns on process evaluation and modification for bioethanol separation and production by applying pinch technology. Further, the paper is also focused on obtaining a most energy-efficient process among several processes. Three basic process configurations of bioethanol separation and production were selected for this study. The three separations and production systems are Othmer process, Barbet process and a separation process that operates under vacuum condition. Basically, each process is combination of Danish Distilleries process with a separation system yielding 95% (v/v bioethanol. The production capacity of the plant is estimated about 4 x 107 litre of bioethanol 95% (v/v per year. The result of the studies shows that the most energy efficient process among the three processes evaluated is the Othmer process, followed by the Barbet process and the process involving vacuum operation. The evaluation also shows that further energy saving can be carried for Barbet and Othmer process configuration when Tmin = 10oC for heat exchange possible.

  5. Demand-side management process evaluations - the management perspective

    International Nuclear Information System (INIS)

    Perrault, G.A.; Barrett, L.B.

    1993-01-01

    A demand-side management (DSM) process evaluation is a qualitative, expert assessment of how a utility marketing program is being conducted. It reviews the efficiency and effectiveness in which a utility plans, manages, executes, and monitors the delivery of DSM programs to its marketplace. Process evaluations,which includes load impact, customer satisfaction and cost-effectiveness analysis, are becoming an increasingly significant component. The process evaluation focus is on the program planning and delivery process as opposed to the energy impacts resulting from the specific measures or products of the program. Because of this process-oriented focus, such evaluations can identify important opportunities for improving the cost-effectiveness of a program without significantly changing product lines. The evaluation may identify administrative or delivery process improvements. In addition, the evaluation may identify ways of improving the degree to which the customer is satisfied with the program or the utility. Since process evaluations are usually conducted as part of a utility's mandated DSM measurement and evaluation plan, they tend to focus mainly on the stated needs of the regulator as opposed to company management. This can be a problem. Although the regulatory perspective is important, in an increasingly competitive business environment, utilities must not overlook management's business and operational needs for specific information regarding DSM program planning, control, execution, and evaluation. This paper discusses some of the conflicts that exist between the regulator's and management's needs for DSM program evaluation results and presents some approaches for assuring that both needs are met. It is organized to first discuss the scope of a process evaluation, then the evaluation issues, the management concerns, and finally reporting of results

  6. The Role of Evaluation in the School Improvement Process

    Science.gov (United States)

    Lindahl, Ronald A.; Beach, Robert H.

    2013-01-01

    Although evaluation serves many purposes in education, there is virtually unanimous agreement that evaluation is a critical component of all school improvement processes. Hamilton et al. (2003) asserted that "assessment and evaluation should be built into reform programs from the outset" (p. 26). Kimball, Lander, and Thorn (2010)…

  7. Field Artillery Ammunition Processing System (FAAPS) concept evaluation study

    Energy Technology Data Exchange (ETDEWEB)

    Kring, C.T.; Babcock, S.M.; Watkin, D.C.; Oliver, R.P.

    1992-06-01

    The Field Artillery Ammunition Processing System (FAAPS) is an initiative to introduce a palletized load system (PLS) that is transportable with an automated ammunition processing and storage system for use on the battlefield. System proponents have targeted a 20% increase in the ammunition processing rate over the current operation while simultaneously reducing the total number of assigned field artillery battalion personnel by 30. The overall objective of the FAAPS Project is the development and demonstration of an improved process to accomplish these goals. The initial phase of the FAAPS Project and the subject of this study is the FAAPS concept evaluation. The concept evaluation consists of (1) identifying assumptions and requirements, (2) documenting the process flow, (3) identifying and evaluating technologies available to accomplish the necessary ammunition processing and storage operations, and (4) presenting alternative concepts with associated costs, processing rates, and manpower requirements for accomplishing the operation. This study provides insight into the achievability of the desired objectives.

  8. Biogeochemical evolution of a landfill leachate plume, Norman, Oklahoma

    Science.gov (United States)

    Cozzarelli, Isabelle M.; Böhlke, John Karl; Masoner, Jason R.; Breit, George N.; Lorah, Michelle M.; Tuttle, Michele L.W.; Jaeschke, Jeanne B.

    2011-01-01

    Leachate from municipal landfills can create groundwater contaminant plumes that may last for decades to centuries. The fate of reactive contaminants in leachate-affected aquifers depends on the sustainability of biogeochemical processes affecting contaminant transport. Temporal variations in the configuration of redox zones downgradient from the Norman Landfill were studied for more than a decade. The leachate plume contained elevated concentrations of nonvolatile dissolved organic carbon (NVDOC) (up to 300 mg/L), methane (16 mg/L), ammonium (650 mg/L as N), iron (23 mg/L), chloride (1030 mg/L), and bicarbonate (4270 mg/L). Chemical and isotopic investigations along a 2D plume transect revealed consumption of solid and aqueous electron acceptors in the aquifer, depleting the natural attenuation capacity. Despite the relative recalcitrance of NVDOC to biodegradation, the center of the plume was depleted in sulfate, which reduces the long-term oxidation capacity of the leachate-affected aquifer. Ammonium and methane were attenuated in the aquifer relative to chloride by different processes: ammonium transport was retarded mainly by physical interaction with aquifer solids, whereas the methane plume was truncated largely by oxidation. Studies near plume boundaries revealed temporal variability in constituent concentrations related in part to hydrologic changes at various time scales. The upper boundary of the plume was a particularly active location where redox reactions responded to recharge events and seasonal water-table fluctuations. Accurately describing the biogeochemical processes that affect the transport of contaminants in this landfill-leachate-affected aquifer required understanding the aquifer's geologic and hydrodynamic framework.

  9. PFLOTRAN: Recent Developments Facilitating Massively-Parallel Reactive Biogeochemical Transport

    Science.gov (United States)

    Hammond, G. E.

    2015-12-01

    With the recent shift towards modeling carbon and nitrogen cycling in support of climate-related initiatives, emphasis has been placed on incorporating increasingly mechanistic biogeochemistry within Earth system models to more accurately predict the response of terrestrial processes to natural and anthropogenic climate cycles. PFLOTRAN is an open-source subsurface code that is specialized for simulating multiphase flow and multicomponent biogeochemical transport on supercomputers. The object-oriented code was designed with modularity in mind and has been coupled with several third-party simulators (e.g. CLM to simulate land surface processes and E4D for coupled hydrogeophysical inversion). Central to PFLOTRAN's capabilities is its ability to simulate tightly-coupled reactive transport processes. This presentation focuses on recent enhancements to the code that enable the solution of large parameterized biogeochemical reaction networks with numerous chemical species. PFLOTRAN's "reaction sandbox" is described, which facilitates the implementation of user-defined reaction networks without the need for a comprehensive understanding of PFLOTRAN software infrastructure. The reaction sandbox is written in modern Fortran (2003-2008) and leverages encapsulation, inheritance, and polymorphism to provide the researcher with a flexible workspace for prototyping reactions within a massively parallel flow and transport simulation framework. As these prototypical reactions mature into well-accepted implementations, they can be incorporated into PFLOTRAN as native biogeochemistry capability. Users of the reaction sandbox are encouraged to upload their source code to PFLOTRAN's main source code repository, including the addition of simple regression tests to better ensure the long-term code compatibility and validity of simulation results.

  10. Radionuclide release from simulated waste material after biogeochemical leaching of uraniferous mineral samples

    International Nuclear Information System (INIS)

    Williamson, Aimee Lynn; Caron, François; Spiers, Graeme

    2014-01-01

    Biogeochemical mineral dissolution is a promising method for the released of metals in low-grade host mineralization that contain sulphidic minerals. The application of biogeochemical mineral dissolution to engineered leach heap piles in the Elliot Lake region may be considered as a promising passive technology for the economic recovery of low grade Uranium-bearing ores. In the current investigation, the decrease of radiological activity of uraniferous mineral material after biogeochemical mineral dissolution is quantified by gamma spectroscopy and compared to the results from digestion/ICP-MS analysis of the ore materials to determine if gamma spectroscopy is a simple, viable alternative quantification method for heavy nuclides. The potential release of Uranium (U) and Radium-226 ( 226 Ra) to the aqueous environment from samples that have been treated to represent various stages of leaching and passive closure processes are assessed. Dissolution of U from the solid phase has occurred during biogeochemical mineral dissolution in the presence of Acidithiobacillus ferrooxidans, with gamma spectroscopy indicating an 84% decrease in Uranium-235 ( 235 U) content, a value in accordance with the data obtained by dissolution chemistry. Gamma spectroscopy data indicate that only 30% of the 226 Ra was removed during the biogeochemical mineral dissolution. Chemical inhibition and passivation treatments of waste materials following the biogeochemical mineral dissolution offer greater protection against residual U and 226 Ra leaching. Pacified samples resist the release of 226 Ra contained in the mineral phase and may offer more protection to the aqueous environment for the long term, compared to untreated or inhibited residues, and should be taken into account for future decommissioning. - Highlights: • Gamma counting showed an 84% decrease in 235 U after biogeochemical mineral leaching. • Chemical digestion/ICP-MS analysis also showed an 84% decrease in total U. • Over

  11. Biogeochemical controls on mercury methylation in the Allequash Creek wetland.

    Science.gov (United States)

    Creswell, Joel E; Shafer, Martin M; Babiarz, Christopher L; Tan, Sue-Zanne; Musinsky, Abbey L; Schott, Trevor H; Roden, Eric E; Armstrong, David E

    2017-06-01

    We measured mercury methylation potentials and a suite of related biogeochemical parameters in sediment cores and porewater from two geochemically distinct sites in the Allequash Creek wetland, northern Wisconsin, USA. We found a high degree of spatial variability in the methylation rate potentials but no significant differences between the two sites. We identified the primary geochemical factors controlling net methylmercury production at this site to be acid-volatile sulfide, dissolved organic carbon, total dissolved iron, and porewater iron(II). Season and demethylation rates also appear to regulate net methylmercury production. Our equilibrium speciation modeling demonstrated that sulfide likely regulated methylation rates by controlling the speciation of inorganic mercury and therefore its bioavailability to methylating bacteria. We found that no individual geochemical parameter could explain a significant amount of the observed variability in mercury methylation rates, but we found significant multivariate relationships, supporting the widely held understanding that net methylmercury production is balance of several simultaneously occurring processes.

  12. Evaluation of formal educational processes for healthcare professionals.

    Science.gov (United States)

    Otrenti, Eloá; Mira, Vera Lúcia; Bucchi, Sarah Marília; Borges-Andrade, Jairo Eduardo

    2014-01-01

    Analyzing the scientific literature on the evaluation of formal educational processes for healthcare professionals. Integrative literature review in which were reviewed the following databases: VHL, Pubmed and Cochrane. The final sample was composed of 19 articles in Portuguese, English and Spanish published from 2000 to July 2010. The subject of study was the evaluation of formal educational processes for health professionals, which had at least the abstract available online. There is no use of a systematic methodology to evaluate the formal educational processes in this study group. The evaluation focus mainly on the learning of participants, with little attention to the teaching process. There are no evaluations on the impact caused by this type of training in institutions and users of the health system, which can incur the risk of reducing the value of formal education processes. A full evaluation of the formal educational processes for professionals during a longer time is important to assess the impact of these processes and provide information about the necessities of continuing education of this population.

  13. Process Evaluation of a Workers' Health Surveillance Program for Meat Processing Workers

    NARCIS (Netherlands)

    van Holland, Berry J; Brouwer, Sandra; de Boer, Michiel R; Reneman, Michiel F; Soer, Remko

    2016-01-01

    Objective To evaluate the implementation process of a workers' health surveillance (WHS) program in a Dutch meat processing company. Methods Workers from five plants were eligible to participate in the WHS program. The program consisted of four evaluative components and an intervention component.

  14. Process Evaluation of a Workers' Health Surveillance Program for Meat Processing Workers

    NARCIS (Netherlands)

    van Holland, Berry J; Brouwer, Sandra; de Boer, Michiel R; Reneman, Michiel F; Soer, Remko

    2017-01-01

    Objective To evaluate the implementation process of a workers' health surveillance (WHS) program in a Dutch meat processing company. Methods Workers from five plants were eligible to participate in the WHS program. The program consisted of four evaluative components and an intervention component.

  15. NASA Ocean Biogeochemical Model assimilating ESRID data global monthly 2/3x1.25 degrees VR2014

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA Ocean Biogeochemical Model -- Assimilated Monthly Data The NASA Ocean Biogeochemical Model (NOBM) is a comprehensive, interactive ocean biogeochemical model...

  16. Linking soil and sediment properties for research on biogeochemical cycles

    Science.gov (United States)

    Kuhn, Nikolaus J.

    2013-04-01

    Conventional perspectives on soil erosion include the on-site damage to soil and reductions in crop yield, as well as the resulting off-site effects on water quality, runoff and sediment loads in rivers. Our evolving understanding of the Earth System has added a new dimension to the role of soil erosion within the global geochemical cycles. First, the relevance of soil as a nutrient and Carbon (C) pool was recognized. Initially, the role of soils in the global C cycle was largely considered to be limited to a vertical exchange of greenhouse house gases (GHG) between vegetation, soil and atmosphere and thus mostly studied by soil scientists, plant ecologists and climatologists. Even Critical Zone research focused mostly on weathering and regolith properties and ignored lateral fluxes of dissolved or particulate organic matter. Since the late 1990s, a wider role of soils in biogeochemical cycles has emerged. Recent estimates place the lateral movement of C between soil and sediment pools in terrestrial ecosystems (including rivers and lakes) at approximately 0.6 to 1.5 Gt per year. Some of the eroded C is replaced by photosynthesis from the atmosphere, but at a cost of additional emissions, for example due to fertilizer production. The long-term fate of the eroded and deposited soil organic matter is subject to an open debate and suffers from a lack of reliable spatial information on lateral C fluxes and its subsequent fate in terrestrial ecosystems. The connection between soil C pool, GHG emissions and erosion illustrates the relevance of surface processes for the C fluxes between Earth's spheres. Accordingly, soil is now considered as mobile system to make accurate predictions about the consequences of global change for terrestrial biogeochemical cycles and climate feedbacks. This expanded perspective on soils as dynamic pool of weathering regolith, sediment, nutrients and C at the interface between the geospheres requires the analysis of relevant soil properties

  17. Evaluation of DGVMs in tropical areas: linking patterns of vegetation cover, climate and fire to ecological processes

    Science.gov (United States)

    D'Onofrio, Donatella; von Hardenberg, Jost; Baudena, Mara

    2017-04-01

    Many current Dynamic Global Vegetation Models (DGVMs), including those incorporated into Earth System Models (ESMs), are able to realistically reproduce the distribution of the most worldwide biomes. However, they display high uncertainty in predicting the forest, savanna and grassland distributions and the transitions between them in tropical areas. These biomes are the most productive terrestrial ecosystems, and owing to their different biogeophysical and biogeochemical characteristics, future changes in their distributions could have also impacts on climate states. In particular, expected increasing temperature and CO2, modified precipitation regimes, as well as increasing land-use intensity could have large impacts on global biogeochemical cycles and precipitation, affecting the land-climate interactions. The difficulty of the DGVMs in simulating tropical vegetation, especially savanna structure and occurrence, has been associated with the way they represent the ecological processes and feedbacks between biotic and abiotic conditions. The inclusion of appropriate ecological mechanisms under present climatic conditions is essential for obtaining reliable future projections of vegetation and climate states. In this work we analyse observed relationships of tree and grass cover with climate and fire, and the current ecological understanding of the mechanisms driving the forest-savanna-grassland transition in Africa to evaluate the outcomes of a current state-of-the-art DGVM and to assess which ecological processes need to be included or improved within the model. Specifically, we analyse patterns of woody and herbaceous cover and fire return times from MODIS satellite observations, rainfall annual average and seasonality from TRMM satellite measurements and tree phenology information from the ESA global land cover map, comparing them with the outcomes of the LPJ-GUESS DGVM, also used by the EC-Earth global climate model. The comparison analysis with the LPJ

  18. Students’ views on the block evaluation process: A descriptive analysis

    Directory of Open Access Journals (Sweden)

    Ntefeleng E. Pakkies

    2016-03-01

    Full Text Available Background: Higher education institutions have executed policies and practices intended to determine and promote good teaching. Students’ evaluation of the teaching and learning process is seen as one measure of evaluating quality and effectiveness of instruction and courses. Policies and procedures guiding this process are discernible in universities, but it isoften not the case for nursing colleges. Objective: To analyse and describe the views of nursing students on block evaluation, and how feedback obtained from this process was managed.Method: A quantitative descriptive study was conducted amongst nursing students (n = 177 in their second to fourth year of training from one nursing college in KwaZulu-Natal. A questionnaire was administered by the researcher and data were analysed using the Statistical Package of Social Sciences Version 19.0. Results: The response rate was 145 (81.9%. The participants perceived the aim of block evaluation as improving the quality of teaching and enhancing their experiences as students.They questioned the significance of their input as stakeholders given that they had never been consulted about the development or review of the evaluation tool, or the administration process; and they often did not receive feedback from the evaluation they participated in. Conclusion: The college management should develop a clear organisational structure with supporting policies and operational guidelines for administering the evaluation process. The administration, implementation procedures, reporting of results and follow-up mechanisms should be made transparent and communicated to all concerned. Reports and actions related to these evaluations should provide feedback into relevant courses or programmes. Keywords: Student evaluation of teaching; perceptions; undergraduate nursing students; evaluation process

  19. Expert evaluation in NPP safety important systems licensing process

    International Nuclear Information System (INIS)

    Mikhail, A Yastrebenetsky; Vasilchenko, V.N.

    2001-01-01

    Expert evaluation of nuclear power plant safety important systems modernization is an integral part of these systems licensing process. The paper contains some aspects of this evaluation which are based on Ukrainian experience of VVER-1000 and VVER-440 modernization. (authors)

  20. Social Context in Usability Evaluations: Concepts, Processes and Products

    DEFF Research Database (Denmark)

    Jensen, Janne Jul

    , the verbalisation and collaboration of multiple leaders in usability evaluations are affected by acquaintance, and a break down in collaboration or a decrease in verbalisation may cause the test leader to dynamically switch role during the usability evaluation to compensate. However, the influence of non......This thesis addresses social context of usability evaluations. Context plays an important role in usability evaluations. A major part of the context of a usability evaluation is the people involved. This is also often referred to as the social context of the usability evaluation, and although...... social context is considered important, only little research has been done to identify how it influences usability evaluations. In this thesis I explore how social context affects the process and product of a usability evaluation and explain the findings in terms of the theory of behaviour settings...

  1. The "Process" of Process Use: Methods for Longitudinal Assessment in a Multisite Evaluation

    Science.gov (United States)

    Shaw, Jessica; Campbell, Rebecca

    2014-01-01

    Process use refers to the ways in which stakeholders and/or evaluands change as a function of participating in evaluation activities. Although the concept of process use has been well discussed in the literature, exploration of methodological strategies for the measurement and assessment of process use has been limited. Typically, empirical…

  2. Evaluating the Sustainability of Manufacturing: Process and Life Cycle Assessments

    Science.gov (United States)

    The Circular Economy is a popular term in environmental studies, but methods are needed to quickly and accurately evaluate recycling opportunities rather than assuming that recycling is appropriate. Through the study of recycling processes (i.e., processes that turn wastes into ...

  3. A Process For Performance Evaluation Of Real-Time Systems

    Directory of Open Access Journals (Sweden)

    Andrew J. Kornecki

    2003-12-01

    Full Text Available Real-time developers and engineers must not only meet the system functional requirements, but also the stringent timing requirements. One of the critical decisions leading to meeting these timing requirements is the selection of an operating system under which the software will be developed and run. Although there is ample documentation on real-time systems performance and evaluation, little can be found that combines such information into an efficient process for use by developers. As the software industry moves towards clearly defined processes, creation of appropriate guidelines describing a process for performance evaluation of real-time system would greatly benefit real-time developers. This technology transition research focuses on developing such a process. PROPERT (PROcess for Performance Evaluation of Real Time systems - the process described in this paper - is based upon established techniques for evaluating real-time systems. It organizes already existing real-time performance criteria and assessment techniques in a manner consistent with a well-formed process, based on the Personal Software Process concepts.

  4. Evaluation criteria for dialogue processes: key findings from RISCOM II

    International Nuclear Information System (INIS)

    Atherton, Elizabeth

    2003-01-01

    As part of Work Package 4 (undertaken by a consortium of partners from the United Kingdom) in the joint European project RISCOM II, work was undertaken on evaluation criteria for determining the success of dialogue processes; this note outlines its key findings as, in order to continue the development of dialogue processes, it is important to evaluate and learn from the experience of engaging with stakeholders. Criteria can be developed to evaluate how successful a process has been, these can range from very practical criteria relating to how well the process worked or be linked to more subjective criteria developed from the aims of the dialogue process itself. Some criteria are particularly relevant to dialogue processes that aim to encourage deliberation and the development of stakeholders' views through participation in the dialogue process: transparency, legitimacy, equality of access, 'being able to speak', a deliberative environment, openness of framing, developing insight into range of issues (new meanings are generated), inclusive and 'best' knowledge elicited, producing acceptable/tolerable and usable outcomes/decisions, improvement of trust and understanding between participants, developing a sense of shared responsibility and common good. Evaluation will incur a cost in terms of time and money, but will help practitioners to be able to develop processes that meet the needs of those who participate and improve the way that we try to engage people in the debate

  5. Evaluation of Citric Acid Production Potentials of Food Processing ...

    African Journals Online (AJOL)

    Objective: To evaluate citric acid production potentials of food processing wastes. Materials and Methods: Samples of domestic wastes generated from peels of Yam (YP), Cassava (CP), red cocoyam (RCP), white cocoyam (WCP), ripe plantain (RP), unripe plantain (UPP) and garri processing chaff (GPC) were washed, ...

  6. Evaluation of mercury retention during the lyophilization process

    International Nuclear Information System (INIS)

    Monteiro, Lucilena R.; Costa, Manuel Q. da

    1997-01-01

    Shrimp and fish samples were studied by comparing the mercury retention during the freeze drying process. Advantages and disadvantages of this technique, a preview procedure, were identified. The food response concerning water mass los and stability on storage are evaluated after freeze drying process. (author). 10 refs., 4 figs., 2 tabs

  7. Image processing system performance prediction and product quality evaluation

    Science.gov (United States)

    Stein, E. K.; Hammill, H. B. (Principal Investigator)

    1976-01-01

    The author has identified the following significant results. A new technique for image processing system performance prediction and product quality evaluation was developed. It was entirely objective, quantitative, and general, and should prove useful in system design and quality control. The technique and its application to determination of quality control procedures for the Earth Resources Technology Satellite NASA Data Processing Facility are described.

  8. Evaluation of the Suitability of Alluxio for Hadoop Processing Frameworks

    CERN Document Server

    Lawrie, Christopher; CERN. Geneva. IT Department

    2016-01-01

    Alluxio is an open source memory speed virtual distributed storage platform. It sits between the storage and processing framework layers for big data processing and claims to heavily improve performance when data is required to be written/read at a high throughput; for example when a dataset is used by many jobs simultaneously. This report evaluates the viability of using Alluxio at CERN for Hadoop processing frameworks.

  9. Evaluated Nuclear Data Processing and Nuclear Reactor Calculations

    Science.gov (United States)

    Williams, P. J. S.; Jones, G. O. L.; Jones, B.; Opgenoorth, H.; Hägström, I.

    1991-01-01

    The following sections are included: * Introduction * Activities Associated with Nuclear Data * Basic nuclear data production * Nuclear data evaluation * Evaluated nuclear data processing * Nuclear data applications * Nuclear Data Classification * Basic nuclear data * Evaluated nuclear data libraries * Problem-Independent Group Constants Libraries * Multigroup Constants Libraries * Problem Dependent Few-Group Constants * Definition of Group Averaged Constants * Single valued energy dependent parameters * Differential energy-angle dependent parameters * The Resonance region * Group condensation * Spatial homogenisation * A Multigroup Library Update - An Example * Multigroup library format * Library update strategy * The choice of the processing codes * Possible sources of error * Summary * References

  10. Biogeochemical processes of incorporation and transformation of 14C labelled fulvic acid, humic acid and simple organic molecules at the sediment-water interface (submarine canyon of the NW Mediterranean)

    International Nuclear Information System (INIS)

    Buscail, R.; Gadel, F.

    1987-01-01

    The input of organic compounds at the marine water-sediment interface was simulated by the injection of 14 C labelled raygrass fulvic and humic acids and glutamic acid in the overlying water of three identically preserved interfaces. After incubations of 6 days under in situ conditions (13 0 C, oxidizing conditions), separation of the resulting products are carried out by successive chemical extractions. They correspond to the relative importance of biological (respiration, assimilation) and geochemical (condensation in geopolymers and adsorption) processes. Two experiments have showed predominance of biological processes (with 14 C fulvic and glutamic acids), while in the case of 14 C humic acid, incorporation in sediment and geochemical processes are more important. (Auth.)

  11. Focusing on the Interfaces, Estuaries and Redox Transition Zones, for Understanding the Microbial Processes and Biogeochemical Cycling of Carbon under the Looming Influence of Global Warming and Anthropogenic Perturbations

    Science.gov (United States)

    Dang, H.; Jiao, N.

    2013-12-01

    Estuaries are the natural interface between terrestrial and marine ecosystems. These are also the zones where human activities exert the strongest impact on the earth and ocean environments. Due to high pressure from the effects of global warming and anthropogenic activities, many estuaries are deteriorating and experiencing significant change of the ecological processes and environmental functions. Certain fundamental microbial processes, including carbon fixation and respiration, have been changing as responses to and consequences of the altered estuarine environment and geochemistry. Increased inputs of terrigenous and anthropogenic organic materials and nutrients and elevated temperature make estuaries easy to be subjected to harmful algal blooms and hypoxic and even anoxic events. The change of the redox status of the estuarine and coastal waters and the increased nutrient loads such as that from terrestrial nitrate stimulate anaerobic respiration processes, such as nitrate reduction and denitrification. This may have strong negative impact on the marine environment, ecosystem and even climate, such as those caused by greenhouse gas production (N2O, CH4) by anaerobic microbial processes. In addition, some nutrients may be consumed by anaerobically respiring heterotrophic microorganisms, instead of being utilized by phytoplankton for carbon fixation. In this regard, the ecological function of the estuarine ecosystem may be altered and the ecological efficiency may be lowered, as less energy is produced by the microbial respiration process and less carbon is fixed by phytoplankton. However, on the other side, in hypoxic and anoxic waters, inorganic carbon fixation by anaerobic microorganisms may happen, such as those via the chemolithoautotrophic denitrifying sulfur oxidizing process and the anaerobic ammonium oxidation (anammox) process. Global warming and anthropogenic perturbations may have lowered the diversity, complexity, stability and sustainability of

  12. Process evaluation of an exercise counseling intervention using motivational interviewing.

    Science.gov (United States)

    McCarthy, Margaret M; Dickson, Victoria Vaughan; Katz, Stuart D; Sciacca, Kathleen; Chyun, Deborah A

    2015-05-01

    To describe the results of the process evaluation of an exercise counseling intervention using motivational interviewing (MI). Exercise can safely be incorporated into heart failure self-care, but many lack access to cardiac rehabilitation. One alternative is to provide exercise counseling in the clinical setting. This process evaluation was conducted according to previously established guidelines for health promotion programs. This includes an assessment of recruitment and retention, implementation, and reach. Desired number of subjects were recruited, but 25% dropped out during study. Good fidelity to the intervention was achieved; the use of MI was evaluated with improvement in adherence over time. Dose included initial session plus 12 weekly phone calls. Subjects varied in participation of daily diary usage. Setting was conducive to recruitment and data collection. Evaluating the process of an intervention provides valuable feedback on content, delivery and fidelity. Copyright © 2014 Elsevier Inc. All rights reserved.

  13. Methods for the Evaluation of Waste Treatment Processes

    Directory of Open Access Journals (Sweden)

    Hans-Joachim Gehrmann

    2017-01-01

    Full Text Available Decision makers for waste management are confronted with the problem of selecting the most economic, environmental, and socially acceptable waste treatment process. This paper elucidates evaluation methods for waste treatment processes for the comparison of ecological and economic aspects such as material flow analysis, statistical entropy analysis, energetic and exergetic assessment, cumulative energy demand, and life cycle assessment. The work is based on the VDI guideline 3925. A comparison of two thermal waste treatment plants with different process designs and energy recovery systems was performed with the described evaluation methods. The results are mainly influenced by the type of energy recovery, where the waste-to-energy plant providing district heat and process steam emerged to be beneficial in most aspects. Material recovery options from waste incineration were evaluated according to sustainability targets, such as saving of resources and environmental protection.

  14. Evaluation of EMG processing techniques using Information Theory

    Directory of Open Access Journals (Sweden)

    Felice Carmelo J

    2010-11-01

    Full Text Available Abstract Background Electromyographic signals can be used in biomedical engineering and/or rehabilitation field, as potential sources of control for prosthetics and orthotics. In such applications, digital processing techniques are necessary to follow efficient and effectively the changes in the physiological characteristics produced by a muscular contraction. In this paper, two methods based on information theory are proposed to evaluate the processing techniques. Methods These methods determine the amount of information that a processing technique is able to extract from EMG signals. The processing techniques evaluated with these methods were: absolute mean value (AMV, RMS values, variance values (VAR and difference absolute mean value (DAMV. EMG signals from the middle deltoid during abduction and adduction movement of the arm in the scapular plane was registered, for static and dynamic contractions. The optimal window length (segmentation, abduction and adduction movements and inter-electrode distance were also analyzed. Results Using the optimal segmentation (200 ms and 300 ms in static and dynamic contractions, respectively the best processing techniques were: RMS, AMV and VAR in static contractions, and only the RMS in dynamic contractions. Using the RMS of EMG signal, variations in the amount of information between the abduction and adduction movements were observed. Conclusions Although the evaluation methods proposed here were applied to standard processing techniques, these methods can also be considered as alternatives tools to evaluate new processing techniques in different areas of electrophysiology.

  15. The NEON Aquatic Network: Expanding the Availability of Biogeochemical Data

    Science.gov (United States)

    Vance, J. M.; Bohall, C.; Fitzgerald, M.; Utz, R.; Parker, S. M.; Roehm, C. L.; Goodman, K. J.; McLaughlin, B.

    2013-12-01

    /sediment chemistry, aquatic organisms, geomorphology). The aquatic network will produce ~212 low-level data products for each site. NEON will produce several higher level data products such as measurements of whole-stream metabolism, gross primary productivity, ecosystem respiration, and fluxes of nitrogen, phosphorous and carbon that will enable users to analyze processes on a gross scale. These data may be integrated with NEON's terrestrial and airborne networks to bridge the gap between aquatic and terrestrial biogeochemical research. The NEON Aquatic Network is poised to greatly expand our ability to create more robust biogeochemical models. For example, hydrologic and stable isotope data will allow investigation of terrestrial-aquatic carbon flux. Constraints provided by NEON's terrestrial and atmospheric data concurrent with remotely sensed data will facilitate the scaling to regional and continental scales, potentially leading to greater accuracy in the global carbon budget. The NEON Aquatic Network represents a powerful tool that will give the scientific community access to standardized data over spatiotemporal scales that are needed to answer fundamental questions about natural ecological variability and responses to changes in the environment.

  16. Process evaluations for uranium recovery from scrap material

    International Nuclear Information System (INIS)

    Westphal, B.R.; Benedict, R.W.

    1992-01-01

    The integral Fast Reactor (IFR) concept being developed by Argonne National Laboratory is based on pyrometallurgical processing of spent nuclear metallic fuel with subsequent fabrication into new reactor fuel by an injection casting sequence. During fabrication, a dilute scrap stream containing uranium alloy fines and broken quartz (Vycor) molds in produced. Waste characterization of this stream, developed by using present operating data and chemical analysis was used to evaluate different uranium recovery methods and possible process variations for the return of the recovered metal. Two methods, comminution with size separation and electrostatic separation, have been tested and can recover over 95% of the metal. Recycling the metal to either the electrochemical process or the injection casting was evaluated for the different economic and process impacts. The physical waste parameters and the important separation process variables are discussed with their effects on the viability of recycling the material. In this paper criteria used to establish the acceptable operating limits is discussed

  17. Process Ontology Specification for Enhancing the Process Compliance of a Measurement and Evaluation Strategy

    Directory of Open Access Journals (Sweden)

    Pablo Becker

    2015-04-01

    Full Text Available In this paper, we specify a generic ontology for the process domain considering the related state-of-the-art research literature. As a result, the recently built process ontology contributes to enrich semantically the terms for the (previously developed measurement and evaluation domain ontology by means of stereotypes. One of the underlying hypothesis in this research is that the generic ontology for process can be seen as a reusable artifact which can be used to enrich semantically not only the measurement and evaluation domain ontology but also to other domains involved in different organizational endeavors. For instance, for the measurement domain, now is explicit that the measurement term has the semantic of task, the measure term has the meaning of outcome, and the metric term has the semantic of method, from the process terminological base standpoint. The augmented conceptual framework, i.e. measurement and evaluation concepts plus process concepts, has also a positive impact on the GOCAME (Goal-Oriented Context-Aware Measurement and Evaluation strategy capabilities since ensures terminological uniformity, consistency and verifiability to its process and method specifications. In order to illustrate how the augmented conceptual framework impacts on the verifiability of GOCAME process and method specifications in addition to the consistency and comparability of results in measurement and evaluation projects, an ICT (Information and Communications Technology security and risk evaluation case study is used.

  18. Methodological framework for evaluating clinical processes: A cognitive informatics perspective.

    Science.gov (United States)

    Kannampallil, Thomas G; Abraham, Joanna; Patel, Vimla L

    2016-12-01

    We propose a methodological framework for evaluating clinical cognitive activities in complex real-world environments that provides a guiding framework for characterizing the patterns of activities. This approach, which we refer to as a process-based approach, is particularly relevant to cognitive informatics (CI) research-an interdisciplinary domain utilizing cognitive approaches in the study of computing systems and applications-as it provides new ways for understanding human information processing, interactions, and behaviors. Using this approach involves the identification of a process of interest (e.g., a clinical workflow), and the contributing sequences of activities in that process (e.g., medication ordering). A variety of analytical approaches can then be used to characterize the inherent dependencies and relations within the contributing activities within the considered process. Using examples drawn from our own research and the extant research literature, we describe the theoretical foundations of the process-based approach, relevant practical and pragmatic considerations for using such an approach, and a generic framework for applying this approach for evaluation studies in clinical settings. We also discuss the potential for this approach in future evaluations of interactive clinical systems, given the need for new approaches for evaluation, and significant opportunities for automated, unobtrusive data collection. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Major outputs of the recent multidisciplinary biogeochemical researches undertaken in the Aegean Sea

    Science.gov (United States)

    Lykousis, V.; Chronis, G.; Tselepides, A.; Price, N. B.; Theocharis, A.; Siokou-Frangou, I.; Van Wambeke, F.; Danovaro, R.; Stavrakakis, S.; Duineveld, G.; Georgopoulos, D.; Ignatiades, L.; Souvermezoglou, A.; Voutsinou-Taliadouri, F.

    2002-06-01

    The main outputs of a multidisciplinary and integrated studies are summarised. The results incorporate the latest biogeochemical researches, at basin scale, in the Aegean Sea (including thermohaline circulation studies, SPM dynamics, mass and energy fluxes, acknowledge biochemical processes in the euphotic and the benthic layer and benthic response to downward fluxes). The data were acquired within five (seasonal) research cruises, during 1997-1998. Data analysis and evaluation hence provided important new information on the functional processes of the Aegean ecosystem. In terms of water circulation, no new deep water formation in the Aegean Sea was observed, during 1997-1998, but rather intermediate water, due mainly to the mild winter conditions. All the biochemical parameters of the euphotic zone (nutrients, Particulate Organic Carbon (POC), chlorophyll- a, phytoplankton, primary and bacterial production), although high in the N. Aegean Sea reflect clearly the highly oligotrophic character of the Aegean Sea. In the N. Aegean, microbial food web was the main pathway of carbon, whereas in the S. Aegean, the food web could be classified as multivorous. An important Black Sea Water (BSW) signal was observed in the dissolved phase; this was especially pronounced in the Dissolved Organic Carbon (DOC), Mn and to a lesser degree to Cd, Cu and Ni concentrations. The downward material fluxes are higher in the N. Aegean, relative to the S. Aegean. Substantially higher values of near-bottom mass fluxes were measured in the deep basins of the N. Aegean, implying significant deep lateral fluxes of POM. The N. Aegean could be classified as a "continental margin" ecosystem, whilst the S. Aegean is a typical "oceanic margin" environment. There is a close relationship and, consequently, coupling between the near-bottom mass fluxes and the accumulation rates of organic matter (OM), with the near-bottom mineralisation, bioturbation, redox potential, oxygen consumption rates, the

  20. Evaluating sources and processing of nonpoint source nitrate in a small suburban watershed in China

    Science.gov (United States)

    Han, Li; Huang, Minsheng; Ma, Minghai; Wei, Jinbao; Hu, Wei; Chouhan, Seema

    2018-04-01

    Identifying nonpoint sources of nitrate has been a long-term challenge in mixed land-use watershed. In the present study, we combine dual nitrate isotope, runoff and stream water monitoring to elucidate the nonpoint nitrate sources across land use, and determine the relative importance of biogeochemical processes for nitrate export in a small suburban watershed, Longhongjian watershed, China. Our study suggested that NH4+ fertilizer, soil NH4+, litter fall and groundwater were the main nitrate sources in Longhongjian Stream. There were large changes in nitrate sources in response to season and land use. Runoff analysis illustrated that the tea plantation and forest areas contributed to a dominated proportion of the TN export. Spatial analysis illustrated that NO3- concentration was high in the tea plantation and forest areas, and δ15N-NO3 and δ18O-NO3 were enriched in the step ponds. Temporal analysis showed high NO3- level in spring, and nitrate isotopes were enriched in summer. Study as well showed that the step ponds played an important role in mitigating nitrate pollution. Nitrification and plant uptake were the significant biogeochemical processes contributing to the nitrogen transformation, and denitrification hardly occurred in the stream.

  1. Automated Plasma Spray (APS) process feasibility study: Plasma spray process development and evaluation

    Science.gov (United States)

    Fetheroff, C. W.; Derkacs, T.; Matay, I. M.

    1979-01-01

    An automated plasma spray (APS) process was developed to apply two layer (NiCrAlY and ZrO2-12Y2O3) thermal-barrier coatings to aircraft gas turbine engine blade airfoils. The APS process hardware consists of four subsystems: a mechanical blade positioner incorporating two interlaced six-degree-of-freedom assemblies; a noncoherent optical metrology subsystem; a microprocessor-based adaptive system controller; and commercial plasma spray equipment. Over fifty JT9D first stage turbine blades specimens were coated with the APS process in preliminary checkout and evaluation studies. The best of the preliminary specimens achieved an overall coating thickness uniformity of + or - 53 micrometers, much better than is achievable manually. Factors limiting this performance were identified and process modifications were initiated accordingly. Comparative evaluations of coating thickness uniformity for manually sprayed and APS coated specimens were initiated. One of the preliminary evaluation specimens was subjected to a torch test and metallographic evaluation.

  2. Integrating Usability Evaluations into the Software Development Process

    DEFF Research Database (Denmark)

    Lizano, Fulvio

    as relevant and strategic human–computer interaction (HCI) activities in the software development process, there are obstacles that limit the complete, effective and efficient integration of this kind of testing into the software development process. Two main obstacles are the cost of usability evaluations...... and the software developers' resistance to accepting users’ opinions regarding the lack of usability in their software systems. The ‘cost obstacle’ refers to the constraint of conducting usability evaluations in the software process due to the significant amount of resources required by this type of testing. Some...... to overcome the resistance obstacle, some studies suggested involving software developers, alongside users, in the conduction or observation of usability evaluations. In this thesis, I am proposing a comprehensive approach for both obstacles by using a synchronous remote usability testing method called remote...

  3. Multiscale Investigation on Biofilm Distribution and Its Impact on Macroscopic Biogeochemical Reaction Rates: BIOFILM DISTRIBUTION AND RATE SCALING

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Zhifeng [Institute of Surface-Earth System Science, Tianjin University, Tianjin China; Pacific Northwest National Laboratory, Richland WA USA; Liu, Chongxuan [Pacific Northwest National Laboratory, Richland WA USA; School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen China; Liu, Yuanyuan [Pacific Northwest National Laboratory, Richland WA USA; School of Earth Science and Engineering, Nanjing University, Nanjing China; Bailey, Vanessa L. [Pacific Northwest National Laboratory, Richland WA USA

    2017-11-01

    Biofilms are critical locations for biogeochemical reactions in the subsurface environment. The occurrence and distribution of biofilms at microscale as well as their impacts on macroscopic biogeochemical reaction rates are still poorly understood. This paper investigated the formation and distributions of biofilms in heterogeneous sediments using multiscale models, and evaluated the effects of biofilm heterogeneity on local and macroscopic biogeochemical reaction rates. Sediment pore structures derived from X-ray computed tomography were used to simulate the microscale flow dynamics and biofilm distribution in the sediment column. The response of biofilm formation and distribution to the variations in hydraulic and chemical properties was first examined. One representative biofilm distribution was then utilized to evaluate its effects on macroscopic reaction rates using nitrate reduction as an example. The results revealed that microorganisms primarily grew on the surfaces of grains and aggregates near preferential flow paths where both electron donor and acceptor were readily accessible, leading to the heterogeneous distribution of biofilms in the sediments. The heterogeneous biofilm distribution decreased the macroscopic rate of biogeochemical reactions as compared with those in homogeneous cases. Operationally considering the heterogeneous biofilm distribution in macroscopic reactive transport models such as using dual porosity domain concept can significantly improve the prediction of biogeochemical reaction rates. Overall, this study provided important insights into the biofilm formation and distribution in soils and sediments as well as their impacts on the macroscopic manifestation of reaction rates.

  4. Evaluation of mercury in the liquid waste processing facilities

    Energy Technology Data Exchange (ETDEWEB)

    Jain, Vijay [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Shah, Hasmukh [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Occhipinti, John E. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Wilmarth, William R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Edwards, Richard E. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-08-13

    This report provides a summary of Phase I activities conducted to support an Integrated Evaluation of Mercury in Liquid Waste System (LWS) Processing Facilities. Phase I activities included a review and assessment of the liquid waste inventory and chemical processing behavior of mercury using a system by system review methodology approach. Gaps in understanding mercury behavior as well as action items from the structured reviews are being tracked. 64% of the gaps and actions have been resolved.

  5. [Evaluation of microbial contamination of linens in industrial laundry processes].

    Science.gov (United States)

    Sanna, Adriana; Coroneo, Valentina; Dessì, Sandro; Brandas, Valeria

    2013-01-01

    Laundering linens and protecting them from microbiological recontamination are critical issues for the hotel and food industries and especially for hospitals. This study was performed to evaluate a sample of industrial laundries in Sardinia (Italy), to assess their compliance with national hygienic and sanitary regulations, along the complete laundering process. Study results indicate that industrial laundering processes are effective and that better awareness of staff who handle laundered textiles is required to reduce the risk of recontamination.

  6. Impact of phenanthrene on the properties of biogeochemical interfaces in soil: A two-layer column study

    Science.gov (United States)

    Reichel, Katharina; Totsche, Kai Uwe

    2013-04-01

    Biogeochemical interfaces in soils (Totsche et al. 2010) are the "hot spots" of microbial activity and the processing of organic compounds in soils. The production and relocation of mobile organic matter (MOM) and biocolloids like microorganisms are key processes for the formation and depth propagation of biogeochemical interfaces in soils (BGI). Phenanthrene (PHE) has been shown to affect microbial communities in soils (Ding et al. 2012) and may induce shifts in MOM quantity and quality (amount, type and properties of MOM). We hypothesize that the properties of BGI in soil change significantly due to the presence of PHE. The objectives of this study are (i) to evaluate the effect of PHE on soil microbial communities and on MOM quantity and quality under flow conditions with single- and two-layer column experiments and (ii) to assess the role of these processes for the physicochemical, mechanical and sorptive properties of BGI in soils. The soil columns were operated under water-unsaturated conditions. The top layer (source layer, SL, 2 cm) is made of sieved soil material (Luvisol, Scheyern, Germany) spiked with PHE (0.2 mg/g). The bottom layer (reception layer, RL, 10 cm) comprised the same soil without PHE. PHE-free columns were conducted in parallel as reference. Release and transport of MOM in mature soil of a single-layer column experiment was found to depend on the transport regime. The release of larger sized MOM (>0.45 µm) was restricted to an increased residence time during flow interruptions. Steady flow conditions favor the release of smaller MOM (10.3389/fmicb.2012.00290.

  7. Green Infrastructure Increases Biogeochemical Responsiveness, Vegetation Growth and Decreases Runoff in a Semi-Arid City, Tucson, AZ, USA

    Science.gov (United States)

    Meixner, T.; Papuga, S. A.; Luketich, A. M.; Rockhill, T.; Gallo, E. L.; Anderson, J.; Salgado, L.; Pope, K.; Gupta, N.; Korgaonkar, Y.; Guertin, D. P.

    2017-12-01

    Green Infrastructure (GI) is often viewed as a mechanism to minimize the effects of urbanization on hydrology, water quality, and other ecosystem services (including the urban heat island). Quantifying the effects of GI requires field measurements of the dimensions of biogeochemical, ecosystem, and hydrologic function that we expect GI to impact. Here we investigated the effect of GI features in Tucson, Arizona which has a low intensity winter precipitation regime and a high intensity summer regime. We focused on understanding the effect of GI on soil hydraulic and biogeochemical properties as well as the effect on vegetation and canopy temperature. Our results demonstrate profound changes in biogeochemical and hydrologic properties and vegetation growth between GI systems and nearby control sites. In terms of hydrologic properties GI soils had increased water holding capacity and hydraulic conductivity. GI soils also have higher total carbon, total nitrogen, and organic matter in general than control soils. Furthermore, we tested the sampled soils (control and GI) for differences in biogeochemical response upon wetting. GI soils had larger respiration responses indicating greater biogeochemical activity overall. Long-term Lidar surveys were used to investigate the differential canopy growth of GI systems versus control sites. The results of this analysis indicate that while a significant amount of time is needed to observe differences in canopy growth GI features due increase tree size and thus likely impact street scale ambient temperatures. Additionally monitoring of transpiration, soil moisture, and canopy temperature demonstrates that GI features increase vegetation growth and transpiration and reduce canopy temperatures. These biogeochemical and ecohydrologic results indicate that GI can increase the biogeochemical processing of soils and increase tree growth and thus reduce urban ambient temperatures.

  8. Understanding oceanic migrations with intrinsic biogeochemical markers.

    Directory of Open Access Journals (Sweden)

    Raül Ramos

    2009-07-01

    Full Text Available Migratory marine vertebrates move annually across remote oceanic water masses crossing international borders. Many anthropogenic threats such as overfishing, bycatch, pollution or global warming put millions of marine migrants at risk especially during their long-distance movements. Therefore, precise knowledge about these migratory movements to understand where and when these animals are more exposed to human impacts is vital for addressing marine conservation issues. Because electronic tracking devices suffer from several constraints, mainly logistical and financial, there is emerging interest in finding appropriate intrinsic markers, such as the chemical composition of inert tissues, to study long-distance migrations and identify wintering sites. Here, using tracked pelagic seabirds and some of their own feathers which were known to be grown at different places and times within the annual cycle, we proved the value of biogeochemical analyses of inert tissue as tracers of marine movements and habitat use. Analyses of feathers grown in summer showed that both stable isotope signatures and element concentrations can signal the origin of breeding birds feeding in distinct water masses. However, only stable isotopes signalled water masses used during winter because elements mainly accumulated during the long breeding period are incorporated into feathers grown in both summer and winter. Our findings shed new light on the simple and effective assignment of marine organisms to distinct oceanic areas, providing new opportunities to study unknown migration patterns of secretive species, including in relation to human-induced mortality on specific populations in the marine environment.

  9. Retrospective (in-process) project evaluation system. Final report

    Energy Technology Data Exchange (ETDEWEB)

    None

    1978-12-20

    The retrospective evaluation methodology, designed to measure the accomplishments of the Buildings and Community Systems projects that are either on-going or completed, is described. The Threshold Screening system and risk analysis methodologies are briefly described. The result of the addition of the retrospective (in-process) evaluation methodology to the threshold/risk analysis and resource allocation methodology is one system by which a project can be screened when it is proposed, monitored in its development, and evaluated at its completion. This report describes the methodology at this early point in its development.

  10. Effects of sea-ice and biogeochemical processes and storms on under-ice water fCO2 during the winter-spring transition in the high Arctic Ocean: Implications for sea-air CO2 fluxes

    Science.gov (United States)

    Fransson, Agneta; Chierici, Melissa; Skjelvan, Ingunn; Olsen, Are; Assmy, Philipp; Peterson, Algot K.; Spreen, Gunnar; Ward, Brian

    2017-07-01

    We performed measurements of carbon dioxide fugacity (fCO2) in the surface water under Arctic sea ice from January to June 2015 during the Norwegian young sea ICE (N-ICE2015) expedition. Over this period, the ship drifted with four different ice floes and covered the deep Nansen Basin, the slopes north of Svalbard, and the Yermak Plateau. This unique winter-to-spring data set includes the first winter-time under-ice water fCO2 observations in this region. The observed under-ice fCO2 ranged between 315 µatm in winter and 153 µatm in spring, hence was undersaturated relative to the atmospheric fCO2. Although the sea ice partly prevented direct CO2 exchange between ocean and atmosphere, frequently occurring leads and breakup of the ice sheet promoted sea-air CO2 fluxes. The CO2 sink varied between 0.3 and 86 mmol C m-2 d-1, depending strongly on the open-water fractions (OW) and storm events. The maximum sea-air CO2 fluxes occurred during storm events in February and June. In winter, the main drivers of the change in under-ice water fCO2 were dissolution of CaCO3 (ikaite) and vertical mixing. In June, in addition to these processes, primary production and sea-air CO2 fluxes were important. The cumulative loss due to CaCO3 dissolution of 0.7 mol C m-2 in the upper 10 m played a major role in sustaining the undersaturation of fCO2 during the entire study. The relative effects of the total fCO2 change due to CaCO3 dissolution was 38%, primary production 26%, vertical mixing 16%, sea-air CO2 fluxes 16%, and temperature and salinity insignificant.

  11. Process alternatives for HTGR fuel reprocessing wastes: an engineering evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Lin, K. H.

    1977-05-01

    An evaluation has been made of numerous process alternatives for different types of radioactive wastes resulting from reprocessing of HTGR fuels. Discussion of pertinent waste characteristics is followed by a description and an assessment of selected process alternatives. The final phase of the discussion is concerned with identification of research and development needs for specific alternatives. High-level solid wastes from the head-end system, which are unique to HTGR fuel reprocessing, require major process development efforts. Most other types of wastes can reasonably be expected to make use of technologies being developed for LWR wastes, and will require minor to moderate modifications.

  12. Subsurface low pH and carbonate saturation state of aragonite on China side of the North Yellow Sea: combined effects of global atmospheric CO2 increase, regional environmental changes, and local biogeochemical processes

    Science.gov (United States)

    Zhai, W.-D.; Zheng, N.; Huo, C.; Xu, Y.; Zhao, H.-D.; Li, Y.-W.; Zang, K.-P.; Wang, J.-Y.; Xu, X.-M.

    2013-02-01

    Based upon seven field surveys conducted between May 2011 and January 2012, we investigated pH, carbonate saturation state of aragonite (Ωarag), and ancillary parameters on the Chinese side of the North Yellow Sea, a western North Pacific continental margin of major economic importance. Subsurface waters were nearly in equilibrium with air in May and June. From July to October, the fugacity of CO2 (fCO2) of bottom water gradually increased to 697 ± 103 μatm and pH decreased to 7.83 ± 0.07 due to respiration/remineralization processes of primary production induced biogenic particles. In November and January, bottom water fCO2 decreased and pH gradually returned to an air-equilibrated level due to cooling enhanced vertical mixing. The corresponding bottom water Ωarag was 1.74 ± 0.17 (May), 1.77 ± 0.26 (June), 1.70 ± 0.26 (July), 1.72 ± 0.33 (August), 1.32 ± 0.31 (October), 1.50 ± 0.28 (November), and 1.41 ± 0.12 (January). Critically low Ωarag values of 1.0 to 1.2 were mainly observed in subsurface waters in a salinity range of 31.5-32.5 psu in October and November, accounting for ~ 10% of the North Yellow Sea area. Water mass derived from the adjacent Bohai Sea had a typical water salinity of 30.5-31.5 psu, and bottom water Ωarag values ranged mostly between 1.6 and 2.4. This study showed that the carbonate system in the North Yellow Sea was substantially influenced by global atmospheric CO2 increase. The community respiration/remineralization rates in typical North Yellow Sea bottom water mass were estimated at 0.55-1.0 μmol O2 kg-1 d-1 in warm seasons, leading to seasonal drops in subsurface pH and Ωarag. Outflow of the Bohai Sea water mass counteracted the subsurface Ωarag reduction in the North Yellow Sea.

  13. Biogeochemical studies on the distribution of heavy metals in the Elbe estuary

    OpenAIRE

    Ahlf, Wolfgang; Calmano, Wolfgang; Förstner, Ulrich

    1990-01-01

    [Introduction] The mixing of riverwater and seawater in an estuary is accompanied by a large number of biogeochemical and physical processes which change the distribution, partitioning and bioavailability of contaminants. Superimposed particulates may take place, which cause deviations from the theoretical mixing curve between dissolved metal ions and salinity. Seasonal fluctuations and year-to-year variations in concentrations of trace metals must be considered in characterizing the importan...

  14. EVALUATION OF HOTEL SERVICE-PERFORMANCE PROCESS IN BULGARIA

    Directory of Open Access Journals (Sweden)

    Georgina Lukanova

    2010-06-01

    Full Text Available The paper analyses the hotel service-performance process in Bulgarian hotels, which is based on the results of the research about tourists’ opinion on basic moments in service process. One of the most important characteristics of hotel industry is the leading role of the human factor in service-performance process. It cannot be accomplished without the participation of the customer and without the participation of the staff.This makes the evaluation of service process strongly subjective. Because of this, customer needs satisfaction is a big challenge for the hotel management. Under the present conditions of an increased competition, satisfying customers means offering service-performance process, which not only meets, but also exceeds guests’expectations. This can be achieved by a preliminary study of their requirements and expectations.

  15. Synthesis and evaluation of potential ligands for nuclear waste processing

    NARCIS (Netherlands)

    Iqbal, M.

    2012-01-01

    The research presented in this thesis deals with the synthesis and evaluation of new potential ligands for the complexation of actinide and lanthanide ions either for their extraction from bulk radioactive waste or their stripping from an extracted organic phase for final processing of the waste. In

  16. Evaluation of poultry processing practices, related public health laws ...

    African Journals Online (AJOL)

    Evaluation of poultry processing practices, related public health laws and diseases of chickens at slaughter: A pilot study in Kaduna state. ... The PDF file you selected should load here if your Web browser has a PDF reader plug-in installed (for example, a recent version of Adobe Acrobat Reader). If you would like more ...

  17. Does "Practice Make Perfect" in the Evaluation Process?

    Science.gov (United States)

    Ridout, Susan Ramp

    1990-01-01

    Compares perceptions of the K-12 School Evaluative Criteria (1983) among personnel from schools that had previously been through the accreditation/self-study process and personnel who had not. Teachers with no previous experience were able to cope with the self-study with no more difficulty than teachers with experience. (DMM)

  18. Using the analytical hierarchy process to evaluate target signatures

    CSIR Research Space (South Africa)

    Baumbach, J

    2008-10-01

    Full Text Available The Analytical Hierarchy Process (AHP) and the Law of Comparative Judgement (LCJ) are pairwise comparison methods. A large number of observers need to perform an LCJ evaluation in order to get accurate results. LCJ also does not provide an absolute...

  19. EVALUATION OF A PROCESS TO CONVERT BIOMASS TO METHANOL FUEL

    Science.gov (United States)

    The report gives results of a review of the design of a reactor capable of gasifying approximately 50 lb/hr of biomass for a pilot-scale facility to develop, demonstrate, and evaluate the Hynol Process, a high-temperature, high-pressure method for converting biomass into methanol...

  20. HIGH RESOLUTION RESISTIVITY LEAK DETECTION DATA PROCESSING & EVALUATION MEHTODS & REQUIREMENTS

    Energy Technology Data Exchange (ETDEWEB)

    SCHOFIELD JS

    2007-10-04

    This document has two purposes: {sm_bullet} Describe how data generated by High Resolution REsistivity (HRR) leak detection (LD) systems deployed during single-shell tank (SST) waste retrieval operations are processed and evaluated. {sm_bullet} Provide the basic review requirements for HRR data when Hrr is deployed as a leak detection method during SST waste retrievals.

  1. Quality evaluation of processed clay soil samples | Steiner-Asiedu ...

    African Journals Online (AJOL)

    Introduction: This study assessed the microbial quality of clay samples sold on two of the major Ghanaian markets. Methods: The study was a cross-sectional assessing the evaluation of processed clay and effects it has on the nutrition of the consumers in the political capital town of Ghana. The items for the examination was ...

  2. Improving occupational health care for construction workers: a process evaluation

    NARCIS (Netherlands)

    Boschman, Julitta S.; van der Molen, Henk F.; Sluiter, Judith K.; Frings-Dresen, Monique H. W.

    2013-01-01

    To evaluate the process of a job-specific workers' health surveillance (WHS) in improving occupational health care for construction workers. From January to July 2012 were 899 bricklayers and supervisors invited for the job-specific WHS at three locations of one occupational health service

  3. EVALUATION OF BIOMASS REACTIVITY IN HYDROGASIFICATION FOR THE HYNOL PROCESS

    Science.gov (United States)

    The report gives results of an evaluation of the reactivity of poplar wood in hydrogasification under the operating conditions specific for the Hynol process, using a thermobalance reactor. Parameters affecting gasification behavior (e.g., gas velocity, particle size, system pres...

  4. Evaluation of the effect of advanced coagulation process to optimize ...

    African Journals Online (AJOL)

    Evaluation of the effect of advanced coagulation process to optimize the removal of natural organic matter in water (Case study: drinking water of Mashhad's ... and in addition to giving taste, color and odor to the water, they can intervene in the oxidization and removal of heavy metals such as arsenic, iron and manganese.

  5. Technical Evaluation of Sample-Processing, Collection, and Preservation Methods

    Science.gov (United States)

    2014-07-01

    policy document entitled The National Strategy for Biosurveillance was released (White House, July 2012) as part of the National Security Strategy...concept of leveraging existing capabilities to “scan and discern the environment,” which implies the use of current technical biosurveillance ...testing of existing sample-processing technologies are expected to enable in silico evaluations of biosurveillance methodologies, equipment, and

  6. Elementary Teachers' Views on the Creative Writing Process: An Evaluation

    Science.gov (United States)

    Akkaya, Nevin

    2014-01-01

    The goal of this study is to discover and evaluate both the areas of personal interest and the views of 4th and 5th grade classroom teachers regarding the creative writing process. In this study, one of the qualitative study methods, state study, and related to this, single state design which refers to the whole has been chosen. Research was…

  7. 10 CFR 709.15 - Processing counterintelligence evaluation results.

    Science.gov (United States)

    2010-01-01

    ... financial, credit, travel, and other relevant information to resolve any identified issues. Participation by... information is developed by the Office of Health, Safety and Security indicating counterintelligence issues... and Protection of National Security § 709.15 Processing counterintelligence evaluation results. (a) If...

  8. Could Students' Evaluation Be a Pleasant and Effective Process?

    Science.gov (United States)

    Kapachtsi, Venetia; Pantelidi, Ioanna; Stamidou, Markia

    2016-01-01

    The evaluation of students' performance is one of the most important issues of educational reality. ?t strongly attracts the interest of all involved in the process of education: teachers, students, parents and the state as well. This study, is trying to find out, if using the project method, the teacher can assess effectively students, in a…

  9. Evaluation of learning and teaching process in Turkish courses

    Directory of Open Access Journals (Sweden)

    Eyyup COŞKUN

    2010-07-01

    Full Text Available A radical educational reform occurred in Turkey in 2005; and curriculum of primary education courses was renewed. New curriculum was prepared based on constructivist approach. In this scope, curriculum of Turkish course was also renewed. This study aimsat evaluating applications and opinions of teachers and students about learning and teaching process prescribed in Turkish Course (1st-5th Grades Curriculum. Within the scope of the study, semi-structured interview was made with 10 teachers and 12 students.In addition, process teaching a text was evaluated via structured observation method in 5 different classes. According to the results of the study, primary school teachers find some stages in learning – teaching process prescribed in the curriculum unnecessary andtherefore do not apply them. Teachers mentioned that some texts are above the student level; and they sometimes experience time and material problems. It was seen in the present study that teachers do not have enough information about learning and teachingprocess in the new curriculum; they do not have high success levels in the applications; and they usually do not apply the forms for evaluating the process in the curriculum. It was found out that, in spite of these problems, courses are student-centred as prescribed inthe curriculum; and students have positive opinions about stages of learning and teaching process.

  10. A Comprehensive Plan for the Long-Term Calibration and Validation of Oceanic Biogeochemical Satellite Data

    Science.gov (United States)

    Hooker, Stanford B.; McClain, Charles R.; Mannino, Antonio

    2007-01-01

    The primary objective of this planning document is to establish a long-term capability and validating oceanic biogeochemical satellite data. It is a pragmatic solution to a practical problem based primarily o the lessons learned from prior satellite missions. All of the plan's elements are seen to be interdependent, so a horizontal organizational scheme is anticipated wherein the overall leadership comes from the NASA Ocean Biology and Biogeochemistry (OBB) Program Manager and the entire enterprise is split into two components of equal sature: calibration and validation plus satellite data processing. The detailed elements of the activity are based on the basic tasks of the two main components plus the current objectives of the Carbon Cycle and Ecosystems Roadmap. The former is distinguished by an internal core set of responsibilities and the latter is facilitated through an external connecting-core ring of competed or contracted activities. The core elements for the calibration and validation component include a) publish protocols and performance metrics; b) verify uncertainty budgets; c) manage the development and evaluation of instrumentation; and d) coordinate international partnerships. The core elements for the satellite data processing component are e) process and reprocess multisensor data; f) acquire, distribute, and archive data products; and g) implement new data products. Both components have shared responsibilities for initializing and temporally monitoring satellite calibration. Connecting-core elements include (but are not restricted to) atmospheric correction and characterization, standards and traceability, instrument and analysis round robins, field campaigns and vicarious calibration sites, in situ database, bio-optical algorithm (and product) validation, satellite characterization and vicarious calibration, and image processing software. The plan also includes an accountability process, creating a Calibration and Validation Team (to help manage

  11. Effects of increased solar ultraviolet radiation on biogeochemical cycles

    International Nuclear Information System (INIS)

    Zepp, R.G.; Callaghan, T.V.; Erickson, D.J.

    1995-01-01

    Increases in solar UV radiation could affect terrestrial and aquatic biogeochemical cycles thus altering both sources and sinks of greenhouse and chemically important trace gases (e.g., carbon dioxide (CO2), carbon monoxide (CO), carbonyl sulfide (COS). In terrestrial ecosystems, increased UV-B could modify both the production and decomposition of plant matter with concomitant changes in the uptake and release of atmospherically important trace gases. Decomposition processes can be accelerated when UV-B photodegrades surface litter, or retarded when the dominant effect involves changes in the chemical composition of living tissues that reduce the biodegradability of buried litter. These changes in decomposition can affect microbial production of CO2 and other trace gases and also may affect the availability of nutrients essential for plant growth. Primary production can be reduced by enhanced UV-B, but the effect is variable between species and even cultivars of some crops. Likewise, the effects of enhanced UV-B on photoproduction of CO from plant matter is species-dependent and occurs more efficiently from dead than from living matter. Aquatic ecosystems studies in several different locations have shown that reductions in current levels of solar UV-B result in enhanced primary production, and Antarctic experiments under the ozone hole demonstrated that primary production is inhibited by enhanced UV-B. In addition to its effects on primary production, solar UV radiation can reduce bacterioplankton growth in the upper ocean with potentially important effects on marine biogeochemical cycles. Decomposition processes can be retarded when bacterial activity is suppressed by enhanced UV-B radiation or stimulated when solar UV radiation photodegrades aquatic dissolved organic matter. Photodegradation of DOM results in loss of UV absorption and formation of dissolved inorganic carbon, CO, and organic substrates that are readily mineralized or taken up by aquatic

  12. Anterior process calcaneal fractures: a systematic evaluation of associated conditions

    Energy Technology Data Exchange (ETDEWEB)

    Petrover, David [NYU Hospital for Joint Disease, Radiology Department, New York, NY (United States); Hopital Beaujon, Service de Radiologie, Paris (France); Schweitzer, Mark E. [NYU Hospital for Joint Disease, Radiology Department, New York, NY (United States); Laredo, J.D. [Hopital Lariboisiere, Service de Radiologie, Paris (France)

    2007-07-15

    The objective was to evaluate the association, by MRI, of anterior calcaneal process fractures with tarsal coalitions, ankle sprains, and bifurcate ligament abnormalities. A retrospective review of 1,479 foot and ankle MR images was performed, over a period of 5 years, for isolated anterior process fractures of the calcaneus. Fifteen 1.5-T MR examinations were systematically evaluated by two radiologists in consensus. Marrow edema patterns, presence of a calcaneonavicular coalition, as well as bifurcate and anterior talofibular ligaments, were evaluated. There were 15 fractures of the anterior calcaneal process with an incidence of 1%. The average patient age was 51 years (range 25-82). Twelve patients were women and 3 were men. The majority of the fractures (14 out of 15) presented as an edema pattern on T2-weighted images, either diffuse (9 out of 15), or vertical (5 out of 15). One case did not show marrow edema, but rather a hypointense line. Nine patients (60%) demonstrated calcaneonavicular coalition and anterior calcaneal process fracture. In 6 patients (50%) the anterior talofibular ligament (ATFL) was thickened. Three patients did not have axial images, and were classified as non-conclusive for the ATFL evaluation. The bifurcate ligament was thickened with hyperintense signal demonstrating a sprain in 9 out of 13 (69%). Only 2 patients (16.5%) had an anterior calcaneal process fracture without any associated abnormality. We believe that there is a probable association of anterior process fractures and calcaneonavicular coalitions. We also feel, based on our results and the prior literature that there is likely also an association with both ATFL injuries and bifurcate ligament injuries. (orig.)

  13. Anterior process calcaneal fractures: a systematic evaluation of associated conditions

    International Nuclear Information System (INIS)

    Petrover, David; Schweitzer, Mark E.; Laredo, J.D.

    2007-01-01

    The objective was to evaluate the association, by MRI, of anterior calcaneal process fractures with tarsal coalitions, ankle sprains, and bifurcate ligament abnormalities. A retrospective review of 1,479 foot and ankle MR images was performed, over a period of 5 years, for isolated anterior process fractures of the calcaneus. Fifteen 1.5-T MR examinations were systematically evaluated by two radiologists in consensus. Marrow edema patterns, presence of a calcaneonavicular coalition, as well as bifurcate and anterior talofibular ligaments, were evaluated. There were 15 fractures of the anterior calcaneal process with an incidence of 1%. The average patient age was 51 years (range 25-82). Twelve patients were women and 3 were men. The majority of the fractures (14 out of 15) presented as an edema pattern on T2-weighted images, either diffuse (9 out of 15), or vertical (5 out of 15). One case did not show marrow edema, but rather a hypointense line. Nine patients (60%) demonstrated calcaneonavicular coalition and anterior calcaneal process fracture. In 6 patients (50%) the anterior talofibular ligament (ATFL) was thickened. Three patients did not have axial images, and were classified as non-conclusive for the ATFL evaluation. The bifurcate ligament was thickened with hyperintense signal demonstrating a sprain in 9 out of 13 (69%). Only 2 patients (16.5%) had an anterior calcaneal process fracture without any associated abnormality. We believe that there is a probable association of anterior process fractures and calcaneonavicular coalitions. We also feel, based on our results and the prior literature that there is likely also an association with both ATFL injuries and bifurcate ligament injuries. (orig.)

  14. Optical Remote Sensing Algorithm Validation using High-Frequency Underway Biogeochemical Measurements in Three Large Global River Systems

    Science.gov (United States)

    Kuhn, C.; Richey, J. E.; Striegl, R. G.; Ward, N.; Sawakuchi, H. O.; Crawford, J.; Loken, L. C.; Stadler, P.; Dornblaser, M.; Butman, D. E.

    2017-12-01

    More than 93% of the world's river-water volume occurs in basins impacted by large dams and about 43% of river water discharge is impacted by flow regulation. Human land use also alters nutrient and carbon cycling and the emission of carbon dioxide from inland reservoirs. Increased water residence times and warmer temperatures in reservoirs fundamentally alter the physical settings for biogeochemical processing in large rivers, yet river biogeochemistry for many large systems remains undersampled. Satellite remote sensing holds promise as a methodology for responsive regional and global water resources management. Decades of ocean optics research has laid the foundation for the use of remote sensing reflectance in optical wavelengths (400 - 700 nm) to produce satellite-derived, near-surface estimates of phytoplankton chlorophyll concentration. Significant improvements between successive generations of ocean color sensors have enabled the scientific community to document changes in global ocean productivity (NPP) and estimate ocean biomass with increasing accuracy. Despite large advances in ocean optics, application of optical methods to inland waters has been limited to date due to their optical complexity and small spatial scale. To test this frontier, we present a study evaluating the accuracy and suitability of empirical inversion approaches for estimating chlorophyll-a, turbidity and temperature for the Amazon, Columbia and Mississippi rivers using satellite remote sensing. We demonstrate how riverine biogeochemical measurements collected at high frequencies from underway vessels can be used as in situ matchups to evaluate remotely-sensed, near-surface temperature, turbidity, chlorophyll-a derived from the Landsat 8 (NASA) and Sentinel 2 (ESA) satellites. We investigate the use of remote sensing water reflectance to infer trophic status as well as tributary influences on the optical characteristics of the Amazon, Mississippi and Columbia rivers.

  15. Seasonal Distributions of Global Ocean Chlorophyll and Nutrients: Analysis with a Coupled Ocean General Circulation Biogeochemical, and Radiative Model

    Science.gov (United States)

    Gregg, Watson W.

    1999-01-01

    A coupled general ocean circulation, biogeochemical, and radiative model was constructed to evaluate and understand the nature of seasonal variability of chlorophyll and nutrients in the global oceans. The model is driven by climatological meteorological conditions, cloud cover, and sea surface temperature. Biogeochemical processes in the model are determined from the influences of circulation and turbulence dynamics, irradiance availability, and the interactions among three functional phytoplankton groups (diatoms, chorophytes, and picoplankton) and three nutrient groups (nitrate, ammonium, and silicate). Phytoplankton groups are initialized as homogeneous fields horizontally and vertically, and allowed to distribute themselves according to the prevailing conditions. Basin-scale model chlorophyll results are in very good agreement with CZCS pigments in virtually every global region. Seasonal variability observed in the CZCS is also well represented in the model. Synoptic scale (100-1000 km) comparisons of imagery are also in good conformance, although occasional departures are apparent. Agreement of nitrate distributions with in situ data is even better, including seasonal dynamics, except for the equatorial Atlantic. The good agreement of the model with satellite and in situ data sources indicates that the model dynamics realistically simulate phytoplankton and nutrient dynamics on synoptic scales. This is especially true given that initial conditions are homogenous chlorophyll fields. The success of the model in producing a reasonable representation of chlorophyll and nutrient distributions and seasonal variability in the global oceans is attributed to the application of a generalized, processes-driven approach as opposed to regional parameterization, and the existence of multiple phytoplankton groups with different physiological and physical properties. These factors enable the model to simultaneously represent the great diversity of physical, biological

  16. Plant operator performance evaluation based on cognitive process analysis experiment

    International Nuclear Information System (INIS)

    Ujita, H.; Fukuda, M.

    1990-01-01

    This paper reports on an experiment to clarify plant operators' cognitive processes that has been performed, to improve the man-machine interface which supports their diagnoses and decisions. The cognitive processes under abnormal conditions were evaluated by protocol analyses interviews, etc. in the experiment using a plant training simulator. A cognitive process model is represented by a stochastic network, based on Rasmussen's decision making model. Each node of the network corresponds to an element of the cognitive process, such as observation, interpretation, execution, etc. Some observations were obtained as follows, by comparison of Monte Carlo simulation results with the experiment results: A process to reconfirm the plant parameters after execution of a task and feedback paths from this process to the observation and the task definition of next task were observed. The feedback probability average and standard deviation should be determined for each incident type to explain correctly the individual differences in the cognitive processes. The tendency for the operator's cognitive level to change from skill-based to knowledge-based via rule-based behavior was observed during the feedback process

  17. An Automated, Image Processing System for Concrete Evaluation

    International Nuclear Information System (INIS)

    Baumgart, C.W.; Cave, S.P.; Linder, K.E.

    1998-01-01

    Allied Signal Federal Manufacturing ampersand Technologies (FM ampersand T) was asked to perform a proof-of-concept study for the Missouri Highway and Transportation Department (MHTD), Research Division, in June 1997. The goal of this proof-of-concept study was to ascertain if automated scanning and imaging techniques might be applied effectively to the problem of concrete evaluation. In the current evaluation process, a concrete sample core is manually scanned under a microscope. Voids (or air spaces) within the concrete are then detected visually by a human operator by incrementing the sample under the cross-hairs of a microscope and by counting the number of ''pixels'' which fall within a void. Automation of the scanning and image analysis processes is desired to improve the speed of the scanning process, to improve evaluation consistency, and to reduce operator fatigue. An initial, proof-of-concept image analysis approach was successfully developed and demonstrated using acquired black and white imagery of concrete samples. In this paper, the automated scanning and image capture system currently under development will be described and the image processing approach developed for the proof-of-concept study will be demonstrated. A development update and plans for future enhancements are also presented

  18. Bioprocesses: Modelling needs for process evaluation and sustainability assessment

    DEFF Research Database (Denmark)

    Jiménez-Gonzaléz, Concepcion; Woodley, John

    2010-01-01

    development such that they can also be used to evaluate processes against sustainability metrics, as well as economics as an integral part of assessments. Finally, property models will also be required based on compounds not currently present in existing databases. It is clear that many new opportunities......The next generation of process engineers will face a new set of challenges, with the need to devise new bioprocesses, with high selectivity for pharmaceutical manufacture, and for lower value chemicals manufacture based on renewable feedstocks. In this paper the current and predicted future roles...... of process system engineering and life cycle inventory and assessment in the design, development and improvement of sustainable bioprocesses are explored. The existing process systems engineering software tools will prove essential to assist this work. However, the existing tools will also require further...

  19. Implementation evaluation of the business process services incentive programme

    Directory of Open Access Journals (Sweden)

    Nonceba Mashalaba

    2015-10-01

    Full Text Available The paper describes the implementation evaluation of the business process services (BPS incentive programme undertaken by the Department of Trade and Industry (the dti and the Department of Performance Monitoring and Evaluation (DPME as part of the 2012/2013 National Evaluation Plan. The evaluation started on 31 October 2012 and the final report was approved on 17 May 2013. The evaluation covers the period from the inception of the programme in January 2011 to December 2012. The BPS incentive programme was implemented to stimulate the business process sector which contributes to economic growth largely through employment creation. The main objectives of the programme are to attract investment and create employment opportunities through offshoring activities. Twenty-six indicators across the five Development Assistance Community (DAC evaluation criteria were developed. A multi-method approach was undertaken to collect data for each of the indicators. The key findings relate to the operation of the programme and a number of suggestions were made as to how to strengthen it. Overall 3807 jobs have been created through the BPS programme during the period under review. Estimated total investment provided by firms is approximately R2.7 billion. Amongst others, the study recommended that the design of the programme be reviewed and extended, potentially to a five-year period in order to maintain the competitiveness of South Africa as a business process off shoring destination. It is essential to address the skills shortage to ensure the growth and sustainability of the South African BPS industry and finally the uptake of the incentive programme.

  20. [Effects of global climate change on the ecological characteristics and biogeochemical significance of marine viruses--A review].

    Science.gov (United States)

    Yang, Yunlan; Cai, Lanlan; Zhang, Rui

    2015-09-04

    As the most abundance biological agents in the oceans, viruses can influence the physiological and ecological characteristics of host cells through viral infections and lysis, and affect the nutrient and energy cycles of the marine food chain. Thus, they are the major players in the ocean biogeochemical processes. The problems caused by global climate changes, such as sea-surface warming, acidification, nutrients availability, and deoxygenation, have the potential effects on marine viruses and subsequently their ecological and biogeochemical function in the ocean. Here, we reviewed the potential impacts of global climate change on the ecological characteristics (e. g. abundance, distribution, life cycle and the host-virus interactions) and biogeochemical significance (e. g. carbon cycling) of marine viruses. We proposed that marine viruses should not be ignored in the global climate change study.

  1. The role of forcing agents on biogeochemical variability along the southwestern Adriatic coast: The Gulf of Manfredonia case study

    Science.gov (United States)

    Specchiulli, Antonietta; Bignami, Francesco; Marini, Mauro; Fabbrocini, Adele; Scirocco, Tommaso; Campanelli, Alessandra; Penna, Pierluigi; Santucci, Angela; D'Adamo, Raffaele

    2016-12-01

    This study investigates how multiple forcing factors such as rivers, surface marine circulation and winds affect hydrology and biogeochemical processes in the Gulf of Manfredonia and the seas around the Gargano peninsula, in the south-western Adriatic Sea. The study adopted an integrated approach, using in situ and remote sensing data, as well as the output of current models. The data reveal variability in the area's hydrography induced by local freshwater sources, the Western Adriatic Current (WAC) flowing from the north along the Italian coast, and the current patterns under different wind regimes. Specifically, exchange with offshore waters in the gulf induces variability in salinity and biogeochemical content, even within the same season, i.e. winter, in our case. This strong dependence on physical and biogeochemical factors makes the Manfredonia-Gargano ecosystem vulnerable to climate change, which could compromise its important role as a nursery area for the Adriatic Sea.

  2. Microbial extracellular polymeric substances in marine biogeochemical processes

    Digital Repository Service at National Institute of Oceanography (India)

    Bhaskar, P.V.; Bhosle, N.B.

    homopolysaccharide made of a-1-6 glucan monomers with 1?3 branched linkages () and bacteria alginate, a heteropolysaccharide having a combination of D-mannuronic acid and L-guluronic acid linked by b-1,6 linkage ( ). a b REVIEW ARTICLES CURRENT SCIENCE, VOL... extent of bacteria. On the other hand, some of the abiotic modes of TEP production from DOM include bubble adsorption, surface coagultion, turbulent shear and laminar she 11. Once released into the surrounding waters either actively (as EPS...

  3. Preface to: Indian Ocean biogeochemical processes and ecological variability

    Digital Repository Service at National Institute of Oceanography (India)

    Hood, R.R.; Naqvi, S.W.A.; Wiggert, J.D.

    , several nations are deploying coastal observing systems. These, in combination with newly avail able research capabilities and technologies, provide a unique opportunity for staging international, interdisciplinary re search in the Indian Ocean...

  4. Electric currents couple spatially separated biogeochemical processes in marine sediment

    DEFF Research Database (Denmark)

    Nielsen, Lars Peter; Risgaard-Petersen, Nils; Fossing, Henrik

    2010-01-01

    be coupled by electric currents in nature. Here we provide evidence that electric currents running through defaunated sediment couple oxygen consumption at the sediment surface to oxidation of hydrogen sulphide and organic carbon deep within the sediment. Altering the oxygen concentration in the sea water...

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

    Energy Technology Data Exchange (ETDEWEB)

    Harwood, B.J.

    1993-01-01

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

  6. Process Evaluation and Continuous Improvement in Community Youth Programs

    Directory of Open Access Journals (Sweden)

    Jennifer V. Trachtenberg

    2008-06-01

    Full Text Available A method of using process evaluation to provide improvement plans in order to promote community youth programs is described. The core elements of this method include the following: (1 collection and analysis of baseline data, (2 feedback provided to programs describing their strengths and limitations, (3 programs provided with assistance in preparing improvement plans in regard to their baseline data, and (4 follow-up evaluation assessed program changes based on their improvement plans and baseline data. A case study of an inner-city neighborhood youth center is used to demonstrate this method.

  7. Evaluation of British Columbia's environmental assessment process : final report

    International Nuclear Information System (INIS)

    Sadler, B.

    1997-11-01

    An independent and impartial review of the experience in implementing British Columbia's Environmental Assessment (EA) process was presented. B.C.'s EA Act was established on June 30, 1995. The Act was designed to evaluate major development proposals such as oil and gas projects, mine projects and highway projects. A commitment was made at that time to examine the process at an early stage to determine how well it was working. This is the final report of that evaluation. The report was based on a survey questionnaire and consultations with stakeholders and participants in the EA process. While a number of 'systemic' 'strategic' or 'specific' issues have been raised by participants, it was generally concluded that B.C.'s EA Act provides for a consistent, vigorous and neutrally-administered review process for all major development proposals. Recommendations were made on how the EA process might be improved and strengthened. Participation by First Nations representatives on project committees was also reviewed. 6 tabs., 1 fig

  8. The Sustainable Process Index. A new dimension in ecological evaluation

    International Nuclear Information System (INIS)

    Krotscheck, Christian; Narodoslawsky, Michael

    1996-01-01

    The Sustainable Process Index (SPI) is a measure developed to evaluate the viability of processes under sustainable economic conditions. Its advantages are its universal applicability, its scientific basis, the possibility of adoption in process analyses and syntheses, the high sensitivity for sustainable qualities, and the capability of aggregation to one measure. It has proved to be useful in industrial strategic planning. The concept of the SPI is based on the assumption that in a truly sustainable society the basis of economy is the sustainable flow of solar exergy. The conversion of the solar exergy to services needs area. Thus, area becomes the limiting factor of a sustainable economy. The SPI evaluates the areas needed to provide the raw materials and energy demands and to accommodate by-product flows from a process in a sustainable way. It relates these areas to the area available to a citizen in a given geographical (from regional to global) context. The data necessary to calculate the SPI are usually known at an early stage in process development. The result of the computation is the ratio between the area needed to supply a citizen with a given service and the area needed to supply a citizen with all possible services. Thus, it is a measure of the expense of this service in an economy oriented towards sustainability

  9. Comparison and Evaluation of Various Tritium Decontamination Techniques and Processes

    International Nuclear Information System (INIS)

    Gentile, C.A.; Langish, S.W.; Skinner, C.H.; Ciebiera, L.P.

    2005-01-01

    In support of fusion energy development, various techniques and processes have been developed over the past two decades for the removal and decontamination of tritium from a variety of items, surfaces, and components. The motivational force for tritium decontamination by chemical, physical, mechanical, or a combination of these methods, is driven by two underlying forces. The first of these motivational forces is safety. Safety is paramount to the established culture associated with fusion energy. The second of these motivational forces is cost. In all aspects, less tritium contamination equals lower operational and disposal costs. This paper will discuss and evaluate the various processes employed for tritium removal and decontamination

  10. Comparison and Evaluation of Various Tritium Decontamination Techniques and Processes

    International Nuclear Information System (INIS)

    Gentile, C.A.; Langish, S.W.; Skinner, C.H.; Ciebiera, L.P.

    2004-01-01

    In support of fusion energy development, various techniques and processes have been developed over the past two decades for the removal and decontamination of tritium from a variety of items, surfaces, and components. Tritium decontamination, by chemical, physical, mechanical, or a combination of these methods, is driven by two underlying motivational forces. The first of these motivational forces is safety. Safety is paramount to the established culture associated with fusion energy. The second of these motivational forces is cost. In all aspects, less tritium contamination equals lower operational and disposal costs. This paper will discuss and evaluate the various processes employed for tritium removal and decontamination

  11. Depressional Wetlands Affect Watershed Hydrological, Biogeochemical, and Ecological Functions.

    Science.gov (United States)

    Evenson, Grey R; Golden, Heather E; Lane, Charles R; McLaughlin, Daniel L; D'Amico, Ellen

    2018-02-13

    Depressional wetlands of the extensive U.S. and Canadian Prairie Pothole Region afford numerous ecosystem processes that maintain healthy watershed functioning. However, these wetlands have been lost at a prodigious rate over past decades due to drainage for development, climate effects, and other causes. Options for management entities to protect the existing wetlands - and their functions - may focus on conserving wetlands based on spatial location vis-à-vis a floodplain or on size limitations (e.g., permitting smaller wetlands to be destroyed but not larger wetlands). Yet the effects of such management practices and the concomitant loss of depressional wetlands on watershed-scale hydrological, biogeochemical, and ecological functions are largely unknown. Using a hydrological model, we analyzed how different loss scenarios by wetland size and proximal location to the stream network affected watershed storage (i.e., inundation patterns and residence times), connectivity (i.e., streamflow contributing areas), and export (i.e., streamflow) in a large watershed in the Prairie Pothole Region of North Dakota, USA. Depressional wetlands store consequential amounts of precipitation and snowmelt. The loss of smaller depressional wetlands (watershed connectivity and storage characteristics of larger wetlands. The wetland management scenario based on stream proximity (i.e., protecting wetlands 30-m and ~450-m from the stream) alone resulted in considerable landscape heterogeneity loss and decreased inundated area and residence times. With more snowmelt and precipitation available for runoff with wetland losses, contributing area increased across all loss scenarios. We additionally found that depressional wetlands attenuated peak flows; the probability of increased downstream flooding from wetland loss was also consistent across all loss scenarios. It is evident from this study that optimizing wetland management for one end-goal (e.g., protection of large depressional

  12. Process evaluation of the human reliability data bank

    International Nuclear Information System (INIS)

    Miller, D.P.; Comer, K.

    1984-01-01

    The US Nuclear Regulatory Commission and Sandia National Laboratories have been developing a plan for a human reliability data bank since August 1981. This research is in response to the data needs of the nuclear power industry's probabilistic risk assessment community. The three phases of the program are to: (A) develop the data bank concept, (B) develop an implementation plan and conduct a process evaluation, and (C) assist a sponsor in implementing the data bank. The program is now in Phase B. This paper describes the methods used and the results of the process evaluation. Decisions to be made in the future regarding full-scale implementation will be based in part on the outcome of this study

  13. A biogeochemical assessment of the Tono site, Japan

    Science.gov (United States)

    Baker, Steven J.; West, Julia M.; Metcalfe, Richard; Noy, David J.; Yoshida, H.; Aoki, K.

    1998-12-01

    When designing investigations of microbial populations in the subsurface, it is extremely valuable to undertake scoping calculations to estimate the likely microbial abundances and evaluate the effects of contamination during sampling. A biogeochemical assessment of the groundwater and lithologies of the Tono mine, Japan, has been made using the BGS/NAGRA computer code BGSE (Bacterial Growth in Subsurface Environments). This code enables an assessment to be made of the maximum microbial growth rates that may be achieved in ideal circumstances, based on availability of nutrients and energy calculated from mineralogical and groundwater analyses. The effect of drilling fluid/groundwater mixing on biomass was assessed using a hypothetical drilling fluid composition. The results of modelling the mixing between groundwater and drilling fluid shows that the addition of only small concentrations of drilling fluid (<1% (v/v)) to the groundwater gives rise to significant microbial growth rates for the systems studied. Maximum growth rates were observed at ratios of 50:50 (v/v) (groundwater: drilling fluid) for the Akeyo and Toki lower groundwaters, and ratios of 90:10 (v/v) (groundwater:drilling fluid) for the Toki upper and Granite groundwaters. At low ratios of drilling fluid (<1% (v/v)) the limiting factor in each system was the availability of an energy source. This reflects the fact that the system is approaching pristine conditions. However, there was sufficient energy to permit a significant growth rate to be observed.

  14. Fuzzy Comprehensive Evaluation (FCE) in Military Decision Support Processes

    Science.gov (United States)

    2013-12-01

    comprehensive evaluation JCA joint campaign analysis JHSV Joint High-Speed Vessel LCS Littoral Combat Ship MCDM multiple criteria decision-making...criteria decision-making ( MCDM ) method. There are different types of MCDM processes, but all handle problems of subjectivity, ambiguity, and...41 V. CONCLUSIONS A. SUMMARY The FCE method is one of many that solve multiple criteria decision-making ( MCDM ) problems by incorporating

  15. Evaluation of the results of coal jigging process

    Directory of Open Access Journals (Sweden)

    Surowiak Agnieszka

    2017-01-01

    Full Text Available Quality of applied hard coal fuel to combustion processes influence significantly on process efficiency and effects of its influence on surrounding environment. It is particularly important issue in time of Clean Coal Technologies (CTW. The paper presents the analysis of hard coal beneficiation in a jig for getting an optimal recovery of useful fraction in concentrate (combustible matter and not useful fraction (ash and sulfur. On the basis of industrial sampling of coal dust jig the density analysis of collected samples of concentrate and tailings was performed in laboratory conditions. In separated fractions of separation products the yields of products were calculated and the contents of ash and total sulfur were marked in them. On the basis of the results of density and chemical analyzes, separation products balance and appropriate calculations the Fuerstenau beneficiation curves were plotted which allowed to evaluate process and compare results of beneficiation of material containing various components. This is a different approach to evaluation of coal beneficiation effects, so far being used mainly for multi-component metals ores. Furthermore, the evaluation of separation preciseness on the basis of separation curves and factors was done and the statistical analysis of mutual correlations of analyzed parameters was done.

  16. Exergoeconomic evaluation of real processes for coffee roasting

    Directory of Open Access Journals (Sweden)

    Vučković Goran D.

    2016-01-01

    Full Text Available Exergoeconomic methods provide an effective approach for identifying, evaluating and reducing thermodynamic inefficiencies and costs in an energy system. The aim of this paper is to show the potential for cost reduction on the demand side, using the exergoeconomic method in the example of real processes for coffee roasting. More than 6.5•109 kg of coffee beans is roasted worldwide annually, mostly in batch roasters. Near the end of the roast, roasting coffee emits volatile organic compounds, carbon monoxide and other pollutants, which in many industrialized countries have to be oxidized in afterburners. Afterburners release exhaust gases with a temperature of 250-450°C, depending on the roasting process and the method of exhaust gas cleaning. The aim of this paper is to use exergy analysis and exergoeconomic performance evaluation to determine the energy use for coffee roasting and the afterburning process, and evaluate the way to utilize waste heat and reduce costs in the factory. For roasters with the capacity of up to 4 tons of green coffee beans per hour, the potential of heat recovery is 1.1 MW and the possibility to save money is around 60,000 € per year. This case study is similar to many others worldwide, and the results of this analysis could lead to more general conclusions.

  17. The process of clinical assessment: cognitions of the evaluator

    Directory of Open Access Journals (Sweden)

    Carmelo Ibáñez Aguirre

    2013-08-01

    Full Text Available The cognitive paradigm of the past few decades opens several new possibilities for psychological evaluation.  The objective of this essay is to emphasize the possibilities related to the quality of self-evaluation, specifically professional self-assessment, meaning a critical analysis of one’s own evaluation process. In this essay, metacognition activities and strategies are examined, as are the ways in which these activities and strategies relate to metacognition and cognitive skills. The intent of this theoretical essay is to offer answers to the clinical evaluator’s professional experience. The results indicate that the clinical professional must consider strategies to improve metacognition and cognitive skills through reflection, self-analysis and self-criticism to improve the quality and efficiency of their work.

  18. Evaluating the Performance of Taiwan Homestay Using Analytic Network Process

    Directory of Open Access Journals (Sweden)

    Yi-Chung Hu

    2012-01-01

    Full Text Available Homestay industry in Taiwan is not only thriving, but also its operation is moving gradually toward elaboration strategy and in a specialized-operation manner these years. Nevertheless, the evaluation frameworks of the earlier studies were sporadically constructed from an overall perspective of homestays. Moreover, the functions, operational model, and natures of homestays are dissimilar to those of hotels; therefore, if the evaluation criteria of homestays employ the ones of hotels, it would appear to be incoherent and incompatible. This study has accordingly developed and constructed a set of evaluation indicators tailor-made for homestay sector through discussion of literatures and interviewing experts so that the evaluation framework would be more comprehensive and more practical. In the process of interviewing experts, it was discovered that dependences lay on the aspects and criteria. Consequently, this research chose the ANP (analytic network process to get the weights and, further, to acquire the homestay business performance through fuzzy theory. The result reveals, as regards key aspects, homestay proprietors and customer groups both weight the surroundings of the building and features, service quality, operation, and management most. In respect to overall homestay performance, customer groups consider it has reached the satisfactory level.

  19. Student evaluation team focus groups increase students' satisfaction with the overall course evaluation process.

    Science.gov (United States)

    Brandl, Katharina; Mandel, Jess; Winegarden, Babbi

    2017-02-01

    Most medical schools use online systems to gather student feedback on the quality of their educational programmes and services. Online data may be limiting, however, as the course directors cannot question the students about written comments, nor can students engage in mutual problem-solving dialogue with course directors. We describe the implementation of a student evaluation team (SET) process to permit course directors and students to gather shortly after courses end to engage in feedback and problem solving regarding the course and course elements. Approximately 16 students were randomly selected to participate in each SET meeting, along with the course director, academic deans and other faculty members involved in the design and delivery of the course. An objective expert facilitates the SET meetings. SETs are scheduled for each of the core courses and threads that occur within the first 2 years of medical school, resulting in approximately 29 SETs annually. SET-specific satisfaction surveys submitted by students (n = 76) and course directors (n = 16) in 2015 were used to evaluate the SET process itself. Survey data were collected from 885 students (2010-2015), which measured student satisfaction with the overall evaluation process before and after the implementation of SETs. Students and course directors valued the SET process itself as a positive experience. Students felt that SETs allowed their voices to be heard, and that the SET increased the probability of suggested changes being implemented. Students' satisfaction with the overall evaluation process significantly improved after implementation of the SET process. Our data suggest that the SET process is a valuable way to supplement online evaluation systems and to increase students' and faculty members' satisfaction with the evaluation process. © 2016 John Wiley & Sons Ltd and The Association for the Study of Medical Education.

  20. Technical evaluation of proposed Ukrainian Central Radioactive Waste Processing Facility

    Energy Technology Data Exchange (ETDEWEB)

    Gates, R.; Glukhov, A.; Markowski, F.

    1996-06-01

    This technical report is a comprehensive evaluation of the proposal by the Ukrainian State Committee on Nuclear Power Utilization to create a central facility for radioactive waste (not spent fuel) processing. The central facility is intended to process liquid and solid radioactive wastes generated from all of the Ukrainian nuclear power plants and the waste generated as a result of Chernobyl 1, 2 and 3 decommissioning efforts. In addition, this report provides general information on the quantity and total activity of radioactive waste in the 30-km Zone and the Sarcophagus from the Chernobyl accident. Processing options are described that may ultimately be used in the long-term disposal of selected 30-km Zone and Sarcophagus wastes. A detailed report on the issues concerning the construction of a Ukrainian Central Radioactive Waste Processing Facility (CRWPF) from the Ukrainian Scientific Research and Design institute for Industrial Technology was obtained and incorporated into this report. This report outlines various processing options, their associated costs and construction schedules, which can be applied to solving the operating and decommissioning radioactive waste management problems in Ukraine. The costs and schedules are best estimates based upon the most current US industry practice and vendor information. This report focuses primarily on the handling and processing of what is defined in the US as low-level radioactive wastes.

  1. Technical evaluation of proposed Ukrainian Central Radioactive Waste Processing Facility

    International Nuclear Information System (INIS)

    Gates, R.; Glukhov, A.; Markowski, F.

    1996-06-01

    This technical report is a comprehensive evaluation of the proposal by the Ukrainian State Committee on Nuclear Power Utilization to create a central facility for radioactive waste (not spent fuel) processing. The central facility is intended to process liquid and solid radioactive wastes generated from all of the Ukrainian nuclear power plants and the waste generated as a result of Chernobyl 1, 2 and 3 decommissioning efforts. In addition, this report provides general information on the quantity and total activity of radioactive waste in the 30-km Zone and the Sarcophagus from the Chernobyl accident. Processing options are described that may ultimately be used in the long-term disposal of selected 30-km Zone and Sarcophagus wastes. A detailed report on the issues concerning the construction of a Ukrainian Central Radioactive Waste Processing Facility (CRWPF) from the Ukrainian Scientific Research and Design institute for Industrial Technology was obtained and incorporated into this report. This report outlines various processing options, their associated costs and construction schedules, which can be applied to solving the operating and decommissioning radioactive waste management problems in Ukraine. The costs and schedules are best estimates based upon the most current US industry practice and vendor information. This report focuses primarily on the handling and processing of what is defined in the US as low-level radioactive wastes

  2. Hanford underground storage tank waste filtration process evaluation

    International Nuclear Information System (INIS)

    Walker, B.W.; McCabe, D.J.

    1997-01-01

    The purpose of this filter study was to evaluate cross-flow filtration as effective solid-liquid separation technology for treating Hanford wastes, outline operating conditions for equipment, examine the expected filter flow rates, and determine proper cleaning. Two Hanford waste processing applications have been identified as candidates for the use of cross-flow filtration. The first of the Hanford applications involves filtration of the decanted supernate from sludge leaching and washing operations. This process involves the concentration and removal of dilute (0.05 wt percent) fines from the bulk of the supernate. The second application involves filtration to wash and concentrate the sludge during out-of-tank processing. This process employs a relatively concentrated (8 wt percent) solids feed stream. Filter studies were conducted with simulants to evaluate whether 0.5 micron cross-flow sintered metal Mott filters and 0.1 micron cross-flow Graver filters can perform solid-liquid separation of the solid/liquid waste streams effectively. In cross-flow filtration the fluid to be filtered flows in parallel to the membrane surface and generates shearing forces and/or turbulence across the filter medium. This shearing influences formation of filter cake stabilizing the filtrate flow rate

  3. Process monitoring evaluation and implementation for the wood abrasive machining process.

    Science.gov (United States)

    Saloni, Daniel E; Lemaster, Richard L; Jackson, Steven D

    2010-01-01

    Wood processing industries have continuously developed and improved technologies and processes to transform wood to obtain better final product quality and thus increase profits. Abrasive machining is one of the most important of these processes and therefore merits special attention and study. The objective of this work was to evaluate and demonstrate a process monitoring system for use in the abrasive machining of wood and wood based products. The system developed increases the life of the belt by detecting (using process monitoring sensors) and removing (by cleaning) the abrasive loading during the machining process. This study focused on abrasive belt machining processes and included substantial background work, which provided a solid base for understanding the behavior of the abrasive, and the different ways that the abrasive machining process can be monitored. In addition, the background research showed that abrasive belts can effectively be cleaned by the appropriate cleaning technique. The process monitoring system developed included acoustic emission sensors which tended to be sensitive to belt wear, as well as platen vibration, but not loading, and optical sensors which were sensitive to abrasive loading.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-06-05

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

  5. Evaluation of the Central Hearing Process in Parkinson Patients

    Directory of Open Access Journals (Sweden)

    Santos, Rosane Sampaio

    2011-04-01

    Full Text Available Introduction: Parkinson disease (PD is a degenerating disease with a deceitful character, impairing the central nervous system and causing biological, psychological and social changes. It shows motor signs and symptoms characterized by trembling, postural instability, rigidity and bradykinesia. Objective: To evaluate the central hearing function in PD patients. Method: A descriptive, prospect and transversal study, in which 10 individuals diagnosed of PD named study group (SG and 10 normally hearing individuals named control group (CG were evaluated, age average of 63.8 and (SD 5.96. Both groups went through otorhinolaryngological and ordinary audiological evaluations, and dichotic test of alternate disyllables (SSW. Results: In the quantitative analysis, CG showed 80% normality on competitive right-ear hearing (RC and 60% on the competitive left-ear hearing (LC in comparison with the SG that presented 70% on RC and 40% on LC. In the qualitative analysis, the biggest percentage of errors was evident in the SG in the order effect. The results showed a difficulty in identifying a sound when there is another competitive sound and in the memory ability. Conclusion: A qualitative and quantitative difference was observed in the SSW test between the evaluated groups, although statistical data does not show significant differences. The importance to evaluate the central hearing process is emphasized when contributing to the procedures to be taken at the therapeutic follow-up.

  6. Ecotoxicological, ecophysiological and biogeochemical fundamentals of risk assessment

    International Nuclear Information System (INIS)

    Bashkin, V.; Evstafjeva, E.

    1995-01-01

    A quantitative risk assessment (RA) for complex influence of different factors in heavy polluted regions is possible to carry out only on a basis of determination of various links of biogeochemical trophical chains and analysis of the whole biogeochemical structure of the region under study. As an integrative assessment, the human adaptability should be chosen because the majority of trophical chains are closed by man. The given integrative criteria includes biogeochemical, ecophysiological and ecotoxicological assessment of risk factors. Consequently, ecological-biogeochemical regionalization, ecophysiological and ecotoxicological monitoring of human population health are the important approaches to RA. These criteria should be conjugated with LCA of various industrial and agricultural products. At the ultimate degree, the given approaches are needed for areas where traditional pollutants (heavy metals, POPS, pesticides, fertilizers) are enforced sharply by radioactive pollution. Due to the complex influence of pollutants, it is impossible to use individual guidelines. For RA of these complex pollutants, the methods of human adaptability assessment to a polluted environment have to be carried out. These methods include biogeochemical, ecotoxicological and ecophysiological analysis of risk factors as well as quantitative uncertainty analysis. Furthermore, the modern statistical methods such as correlative graphs etc., have to be used for quantitative assessment of human adaptability to complex influence of pollutants. The results obtained in the Chernobyl region have shown the acceptability of suggested methods

  7. A framework to assess biogeochemical response to ecosystem disturbance using nutrient partitioning ratios

    Science.gov (United States)

    Kranabetter, J. Marty; McLauchlan, Kendra K.; Enders, Sara K.; Fraterrigo, Jennifer M.; Higuera, Philip E.; Morris, Jesse L.; Rastetter, Edward B.; Barnes, Rebecca; Buma, Brian; Gavin, Daniel G.; Gerhart, Laci M.; Gillson, Lindsey; Hietz, Peter; Mack, Michelle C.; McNeil, Brenden; Perakis, Steven

    2016-01-01

    Disturbances affect almost all terrestrial ecosystems, but it has been difficult to identify general principles regarding these influences. To improve our understanding of the long-term consequences of disturbance on terrestrial ecosystems, we present a conceptual framework that analyzes disturbances by their biogeochemical impacts. We posit that the ratio of soil and plant nutrient stocks in mature ecosystems represents a characteristic site property. Focusing on nitrogen (N), we hypothesize that this partitioning ratio (soil N: plant N) will undergo a predictable trajectory after disturbance. We investigate the nature of this partitioning ratio with three approaches: (1) nutrient stock data from forested ecosystems in North America, (2) a process-based ecosystem model, and (3) conceptual shifts in site nutrient availability with altered disturbance frequency. Partitioning ratios could be applied to a variety of ecosystems and successional states, allowing for improved temporal scaling of disturbance events. The generally short-term empirical evidence for recovery trajectories of nutrient stocks and partitioning ratios suggests two areas for future research. First, we need to recognize and quantify how disturbance effects can be accreting or depleting, depending on whether their net effect is to increase or decrease ecosystem nutrient stocks. Second, we need to test how altered disturbance frequencies from the present state may be constructive or destructive in their effects on biogeochemical cycling and nutrient availability. Long-term studies, with repeated sampling of soils and vegetation, will be essential in further developing this framework of biogeochemical response to disturbance.

  8. Error assessment of biogeochemical models by lower bound methods (NOMMA-1.0)

    Science.gov (United States)

    Sauerland, Volkmar; Löptien, Ulrike; Leonhard, Claudine; Oschlies, Andreas; Srivastav, Anand

    2018-03-01

    Biogeochemical models, capturing the major feedbacks of the pelagic ecosystem of the world ocean, are today often embedded into Earth system models which are increasingly used for decision making regarding climate policies. These models contain poorly constrained parameters (e.g., maximum phytoplankton growth rate), which are typically adjusted until the model shows reasonable behavior. Systematic approaches determine these parameters by minimizing the misfit between the model and observational data. In most common model approaches, however, the underlying functions mimicking the biogeochemical processes are nonlinear and non-convex. Thus, systematic optimization algorithms are likely to get trapped in local minima and might lead to non-optimal results. To judge the quality of an obtained parameter estimate, we propose determining a preferably large lower bound for the global optimum that is relatively easy to obtain and that will help to assess the quality of an optimum, generated by an optimization algorithm. Due to the unavoidable noise component in all observations, such a lower bound is typically larger than zero. We suggest deriving such lower bounds based on typical properties of biogeochemical models (e.g., a limited number of extremes and a bounded time derivative). We illustrate the applicability of the method with two real-world examples. The first example uses real-world observations of the Baltic Sea in a box model setup. The second example considers a three-dimensional coupled ocean circulation model in combination with satellite chlorophyll a.

  9. NATO Advanced Research Workshop on The Biogeochemical Cycling of Sulfur and Nitrogen in the Remote Atmosphere

    CERN Document Server

    Charlson, Robert; Andreae, Meinrat; Rodhe, Henning

    1985-01-01

    Viewed from space, the Earth appears as a globe without a beginning or an end. Encompassing the globe is the atmosphere with its three phases-­ gaseous, liquid, and solid--moving in directions influenced by sunlight, gravity, and rotation. The chemical compositions of these phases are determined by biogeochemical cycles. Over the past hundred years, the processes governing the rates and reactions in the atmospheric biogeochemical cycles have typically been studied in regions where scientists lived. Hence, as time has gone by, the advances in our knowledge of atmospheric chemical cycles in remote areas have lagged substantially behind those for more populated areas. Not only are the data less abundant, they are also scattered. Therefore, we felt a workshop would be an excellent mechanism to assess the state­ of-knowledge of the atmospheric cycles of sulfur and nitrogen in remote areas and to make recommendations for future research. Thus, a NATO Advanced Research Workshop '~he Biogeochemical Cycling of Sulfu...

  10. Geophysical Monitoring of Hydrological and Biogeochemical Transformations associated with Cr(VI) Bioremediation

    International Nuclear Information System (INIS)

    Hubbard, Susan; Williams, Kenneth H.; Conrad, Mark E.; Faybishenko, Boris; Peterson, John; Chen, Jinsong; Long, Philip E.; Hazen, Terry C.

    2008-01-01

    Understanding how hydrological and biogeochemical properties change over space and time in response to remedial treatments is hindered by our ability to monitor these processes with sufficient resolution and over field relevant scales. Here, we explored the use of geophysical approaches for monitoring the spatiotemporal distribution of hydrological and biogeochemical transformations associated with a Cr(VI)bioremediation experiment performed at Hanford, WA. We first integrated hydrological wellbore and geophysical tomographic datasets to estimate hydrological zonation at the study site. Using results from laboratory biogeophysical experiments and constraints provided by field geochemical datasets, we then interpreted time-lapse seismic and radar tomographic datasets, collected during thirteen acquisition campaigns over a three year experimental period, in terms of hydrological and biogeochemical transformations. The geophysical monitoring datasets were used to infer: the spatial distribution of injected electron donor; the evolution of gas bubbles; variations in total dissolved solids (nitrate and sulfate) as a function of pumping activity; the formation of precipitates and dissolution of calcites; and concomitant changes in porosity. Although qualitative in nature, the integrated interpretation illustrates how geophysical techniques have the potential to provide a wealth of information about coupled hydrobiogeochemical responses to remedial treatments in high spatial resolution and in a minimally invasive manner. Particularly novel aspects of our study include the use of multiple lines of evidence to constrain the interpretation of a long-term, field-scale geophysical monitoring dataset and the interpretation of the transformations as a function of hydrological heterogeneity and pumping activity

  11. Evaluating landscape health: Integrating societal goals and biophysical process

    Science.gov (United States)

    Rapport, D.J.; Gaudet, C.; Karr, J.R.; Baron, Jill S.; Bohlen, C.; Jackson, W.; Jones, B.; Naiman, R.J.; Norton, B.; Pollock, M. M.

    1998-01-01

    Evaluating landscape change requires the integration of the social and natural sciences. The social sciences contribute to articulating societal values that govern landscape change, while the natural sciences contribute to understanding the biophysical processes that are influenced by human activity and result in ecological change. Building upon Aldo Leopold's criteria for landscape health, the roles of societal values and biophysical processes in shaping the landscape are explored. A framework is developed for indicators of landscape health and integrity. Indicators of integrity are useful in measuring biological condition relative to the condition in landscapes largely unaffected by human activity, while indicators of health are useful in evaluating changes in highly modified landscapes. Integrating societal goals and biophysical processes requires identification of ecological services to be sustained within a given landscape. It also requires the proper choice of temporal and spatial scales. Societal values are based upon inter-generational concerns at regional scales (e.g. soil and ground water quality). Assessing the health and integrity of the environment at the landscape scale over a period of decades best integrates societal values with underlying biophysical processes. These principles are illustrated in two contrasting case studies: (1) the South Platte River study demonstrates the role of complex biophysical processes acting at a distance; and (2) the Kissimmee River study illustrates the critical importance of social, cultural and economic concerns in the design of remedial action plans. In both studies, however, interactions between the social and the biophysical governed the landscape outcomes. The legacy of evolution and the legacy of culture requires integration for the purpose of effectively coping with environmental change.

  12. Evaluation of alternative drying techniques for the earthworm flour processing

    Directory of Open Access Journals (Sweden)

    Laura Suárez Hernández

    2016-01-01

    Full Text Available Production of earthworm flour includes several steps, among which the most critical is the drying process due to factors such as time and energ y requirements. In addition, the information available about this process is relquite limited. Thus, this work evaluated four drying techniques likely to be implemented by lombricultores: sun drying, oven drying, drying tunnel and microwave assisted drying. Drying kinetics values were obtained for all drying techniques, and specific parameters as the following were evaluated: drying tray material (stainless and ceramic steel for sun drying, microwave power (30 %, 50 % and 80 % and amount of material to be dried (72 and 100 g for microwave assisted drying, temperature (50, 65, 90 and 100 °C for oven drying, and temperature (50 and 63 °C and air speed (2.9 to 3.6 m/s for tunnel drying. It was determined that the most efficient technique is the drying tunnel, because this allows the combination of heat transfer by conduction and convection, and enables controlling the operating parameters. Finally, nutritional analyzes were performed in samples obtained by each drying technique evaluated. The crude protein content for sun drying, microwave assisted drying, oven drying and tunnel drying were 66.36 %, 67.91 %, 60.35 % and 62.33 % respectively, indicating that the drying method and operating parameters do not significantly affect the crude protein content.

  13. Simplification of flavour combinatorics in evaluation of hadronic processes

    Science.gov (United States)

    Boos, Ernst E.; Ilyin, Viacheslav A.; Skachkova, Anne N.

    2000-05-01

    A serious computational problem in the evaluation of hadronic collision processes is connected with the large number of partonic subprocesses included in the calculation. These are from the quark and gluon content of the initial hadrons, and from CKM quark mixing. For example, there are 180 subprocesses which contribute to the W + 2 jets process, and 292 subprocesses in W + 3 jets production at the LHC, even when quarks from only the first two generations are taken into account. We propose a simple modification of the rules for evaluation of cross sections and distributions, which avoids multiplication of channels from the mixture of quark states. The method is based on a unitary rotation of down quarks, thus, transporting the mixing matrix elements from vertices of Feynman diagrams to the parton distribution functions (PDF). As a result, one can calculate cross sections with significantly fewer subprocesses. For the example mentioned above, with the new rules, one need evaluate only 21 and 33 subprocesses, respectively. The matrix elements of the subprocesses are calculated without quark mixing but with a modified PDF convolution which depends on the quark mixing angle, and on the topologies of gauge invariant classes of diagrams. The proposed method has been incorporated into the CompHEP program and checked with various examples.

  14. Evaluation of the styloid process on digital panoramic radiographs

    International Nuclear Information System (INIS)

    More, Chandramani B; Asrani, Mukesh K

    2010-01-01

    The styloid process is an anatomical structure, whose clinical importance is not well understood. Proper clinical and radiographic evaluation can detect an elongated styloid process and calcification of the stylohyoid ligament. It has been reported that 2 – 28% of the general population show radiographic evidence of mineralization of a portion of the stylohyoid chain. The elongated styloid process may be symptomatic in many cases. Panoramic radiography is the best imaging modality to view the styloid process bilaterally. To assess the styloid process on digital panoramic radiographs. The study was conducted on 500 digital panoramic radiographs available in the archives of our department as soft copies. These radiographs were taken using a digital panoramic system. The radiographic length of the styloid process was measured on both sides using the measurement toolbars on the accompanying analysis software. For statistical analysis we used the unpaired t test, Chi-square test, and one-way ANOVA test, as necessary. The average length of the left styloid was 25.41 ± 6.32 mm and that of the right styloid was 25.53 ± 6.62 mm. The length of both styloids increased with age and males had longer styloids than females. Elongated styloids were present in 19.4% of the panoramic radiographs. Langlais type I elongated styloids and a partial calcification pattern were more common than others. Panoramic radiography is useful for detection of an elongated styloid process and / or ossification of the stylohyoid ligament in patients with or without symptoms, and helps avoid a misdiagnosis of tonsillar pain or pain of dental, pharyngeal, or muscular origin

  15. Evaluation of the styloid process on digital panoramic radiographs

    Directory of Open Access Journals (Sweden)

    More Chandramani

    2010-01-01

    Full Text Available Background: The styloid process is an anatomical structure, whose clinical importance is not well understood. Proper clinical and radiographic evaluation can detect an elongated styloid process and calcification of the stylohyoid ligament. It has been reported that 2 - 28% of the general population show radiographic evidence of mineralization of a portion of the stylohyoid chain. The elongated styloid process may be symptomatic in many cases. Panoramic radiography is the best imaging modality to view the styloid process bilaterally. Aim: To assess the styloid process on digital panoramic radiographs. Materials and Methods: The study was conducted on 500 digital panoramic radiographs available in the archives of our department as soft copies. These radiographs were taken using a digital panoramic system. The radiographic length of the styloid process was measured on both sides using the measurement toolbars on the accompanying analysis software. For statistical analysis we used the unpaired t test, Chi-square test, and one-way ANOVA test, as necessary. Results: The average length of the left styloid was 25.41 ± 6.32 mm and that of the right styloid was 25.53 ± 6.62 mm. The length of both styloids increased with age and males had longer styloids than females. Elongated styloids were present in 19.4% of the panoramic radiographs. Langlais type I elongated styloids and a partial calcification pattern were more common than others. Conclusion: Panoramic radiography is useful for detection of an elongated styloid process and / or ossification of the stylohyoid ligament in patients with or without symptoms, and helps avoid a misdiagnosis of tonsillar pain or pain of dental, pharyngeal, or muscular origin.

  16. Evaluation of peach palm (Bactris gasipaes Kunth) processed by radiation

    International Nuclear Information System (INIS)

    Silva, Priscila Vieira da

    2009-01-01

    The peach palm can be obtained from several species of palms, but the peach palm has attracted great interest by producers, as has characteristics of precocity, rusticity and tillering, producing a palm-quality differentiating it from other palmettos for their sweet flavor and yellowish . The food irradiation has been used as a treatment to ensure microbiological food safety of products to avoid infection. Its use combined with minimal processing could increase the safety and quality of minimally processed vegetables. We aimed at evaluating the effect of gamma radiation and electron beams to control bacteria; assess the physical characteristics through analysis of color and texture in peach palm in natura minimally processed and subjected to ionizing radiation stored at 8 deg C as well as evaluating the sensory characteristics. The results in the microbiological analysis showed that ionizing radiation promotes reduction of microbial load in both treatments. In the analysis of color we can conclude that among all the treatments the sample irradiated with 1.5 kGy showed more differences when compared with the other samples. Observing texture characteristics we could conclude that irradiation changed the texture of the palm, unlike the treatment by electron beams that showed no difference between samples. For the sensory analysis, the gamma radiation with dose of 1.5 kGy, induced changes in sensory properties to the attributes and overall appearance. The dose of 1 kGy caused no significant difference, so a recommended dose for the irradiation of the studied product. (author)

  17. SELECTION AND PRELIMINARY EVALUATION OF ALTERNATIVE REDUCTANTS FOR SRAT PROCESSING

    Energy Technology Data Exchange (ETDEWEB)

    Stone, M.; Pickenheim, B.; Peeler, D.

    2009-06-30

    Defense Waste Processing Facility - Engineering (DWPF-E) has requested the Savannah River National Laboratory (SRNL) to perform scoping evaluations of alternative flowsheets with the primary focus on alternatives to formic acid during Chemical Process Cell (CPC) processing. The reductants shown below were selected for testing during the evaluation of alternative reductants for Sludge Receipt and Adjustment Tank (SRAT) processing. The reductants fall into two general categories: reducing acids and non-acidic reducing agents. Reducing acids were selected as direct replacements for formic acid to reduce mercury in the SRAT, to acidify the sludge, and to balance the melter REDuction/OXidation potential (REDOX). Non-acidic reductants were selected as melter reductants and would not be able to reduce mercury in the SRAT. Sugar was not tested during this scoping evaluation as previous work has already been conducted on the use of sugar with DWPF feeds. Based on the testing performed, the only viable short-term path to mitigating hydrogen generation in the CPC is replacement of formic acid with a mixture of glycolic and formic acids. An experiment using glycolic acid blended with formic on an 80:20 molar basis was able to reduce mercury, while also targeting a predicted REDuction/OXidation (REDOX) of 0.2 expressed as Fe{sup 2+}/{Sigma}Fe. Based on this result, SRNL recommends performing a complete CPC demonstration of the glycolic/formic acid flowsheet followed by a design basis development and documentation. Of the options tested recently and in the past, nitric/glycolic/formic blended acids has the potential for near term implementation in the existing CPC equipment providing rapid throughput improvement. Use of a non-acidic reductant is recommended only if the processing constraints to remove mercury and acidify the sludge acidification are eliminated. The non-acidic reductants (e.g. sugar) will not reduce mercury during CPC processing and sludge acidification would

  18. The biogeochemical iron cycle and astrobiology

    Energy Technology Data Exchange (ETDEWEB)

    Schröder, Christian, E-mail: christian.schroeder@stir.ac.uk [University of Stirling, Biological and Environmental Sciences, School of Natural Sciences (United Kingdom); Köhler, Inga [Eberhard Karls University of Tübingen, Geomicrobiology, Centre for Applied Geoscience (Germany); Muller, Francois L. L. [Qatar University, Department of Biological and Environmental Sciences (Qatar); Chumakov, Aleksandr I.; Kupenko, Ilya; Rüffer, Rudolf [ESRF-The European Synchrotron (France); Kappler, Andreas [Eberhard Karls University of Tübingen, Geomicrobiology, Centre for Applied Geoscience (Germany)

    2016-12-15

    Biogeochemistry investigates chemical cycles which influence or are influenced by biological activity. Astrobiology studies the origin, evolution and distribution of life in the universe. The biogeochemical Fe cycle has controlled major nutrient cycles such as the C cycle throughout geological time. Iron sulfide minerals may have provided energy and surfaces for the first pioneer organisms on Earth. Banded iron formations document the evolution of oxygenic photosynthesis. To assess the potential habitability of planets other than Earth one looks for water, an energy source and a C source. On Mars, for example, Fe minerals have provided evidence for the past presence of liquid water on its surface and would provide a viable energy source. Here we present Mössbauer spectroscopy investigations of Fe and C cycle interactions in both ancient and modern environments. Experiments to simulate the diagenesis of banded iron formations indicate that the formation of ferrous minerals depends on the amount of biomass buried with ferric precursors rather than on the atmospheric composition at the time of deposition. Mössbauer spectra further reveal the mutual stabilisation of Fe-organic matter complexes against mineral transformation and decay of organic matter into CO{sub 2}. This corresponds to observations of a ‘rusty carbon sink’ in modern sediments. The stabilisation of Fe-organic matter complexes may also aid transport of particulate Fe in the water column while having an adverse effect on the bioavailability of Fe. In the modern oxic ocean, Fe is insoluble and particulate Fe represents an important source. Collecting that particulate Fe yields small sample sizes that would pose a challenge for conventional Mössbauer experiments. We demonstrate that the unique properties of the beam used in synchrotron-based Mössbauer applications can be utilized for studying such samples effectively. Reactive Fe species often occur in amorphous or nanoparticulate form in the

  19. The biogeochemical iron cycle and astrobiology

    Science.gov (United States)

    Schröder, Christian; Köhler, Inga; Muller, Francois L. L.; Chumakov, Aleksandr I.; Kupenko, Ilya; Rüffer, Rudolf; Kappler, Andreas

    2016-12-01

    Biogeochemistry investigates chemical cycles which influence or are influenced by biological activity. Astrobiology studies the origin, evolution and distribution of life in the universe. The biogeochemical Fe cycle has controlled major nutrient cycles such as the C cycle throughout geological time. Iron sulfide minerals may have provided energy and surfaces for the first pioneer organisms on Earth. Banded iron formations document the evolution of oxygenic photosynthesis. To assess the potential habitability of planets other than Earth one looks for water, an energy source and a C source. On Mars, for example, Fe minerals have provided evidence for the past presence of liquid water on its surface and would provide a viable energy source. Here we present Mössbauer spectroscopy investigations of Fe and C cycle interactions in both ancient and modern environments. Experiments to simulate the diagenesis of banded iron formations indicate that the formation of ferrous minerals depends on the amount of biomass buried with ferric precursors rather than on the atmospheric composition at the time of deposition. Mössbauer spectra further reveal the mutual stabilisation of Fe-organic matter complexes against mineral transformation and decay of organic matter into CO2. This corresponds to observations of a `rusty carbon sink' in modern sediments. The stabilisation of Fe-organic matter complexes may also aid transport of particulate Fe in the water column while having an adverse effect on the bioavailability of Fe. In the modern oxic ocean, Fe is insoluble and particulate Fe represents an important source. Collecting that particulate Fe yields small sample sizes that would pose a challenge for conventional Mössbauer experiments. We demonstrate that the unique properties of the beam used in synchrotron-based Mössbauer applications can be utilized for studying such samples effectively. Reactive Fe species often occur in amorphous or nanoparticulate form in the environment and

  20. Evaluating supplier quality performance using analytical hierarchy process

    Science.gov (United States)

    Kalimuthu Rajoo, Shanmugam Sundram; Kasim, Maznah Mat; Ahmad, Nazihah

    2013-09-01

    This paper elaborates the importance of evaluating supplier quality performance to an organization. Supplier quality performance evaluation reflects the actual performance of the supplier exhibited at customer's end. It is critical in enabling the organization to determine the area of improvement and thereafter works with supplier to close the gaps. Success of the customer partly depends on supplier's quality performance. Key criteria as quality, cost, delivery, technology support and customer service are categorized as main factors in contributing to supplier's quality performance. 18 suppliers' who were manufacturing automotive application parts evaluated in year 2010 using weight point system. There were few suppliers with common rating which led to common ranking observed by few suppliers'. Analytical Hierarchy Process (AHP), a user friendly decision making tool for complex and multi criteria problems was used to evaluate the supplier's quality performance challenging the weight point system that was used for 18 suppliers'. The consistency ratio was checked for criteria and sub-criteria. Final results of AHP obtained with no overlap ratings, therefore yielded a better decision making methodology as compared to weight point rating system.

  1. Statistical signal processing methods for ultrasonic nondestructive evaluation

    International Nuclear Information System (INIS)

    Saniie, J.

    1992-06-01

    Order statistics and morphological filters belong to a class of nonlinear filters that have recently found many applications in signal analysis and image processing. In this paper, order statistics and morphological filters have been applied to enhance the features of the ultrasonic signal when it has been contaminated by multiple interfering microstructure echoes with random amplitudes and phases. These interfering echoes (i.e., speckles or grain scattering noise) often become significant to the point where detection of flaw echoes becomes very difficult. We have examined order statistic, and morphological filters for improved ultrasonic flaw detection. In particular, the performance of these filters has been evaluated using different ranks of order statistics (minimum, median, maximum), and different shapes of structuring elements in the application of morphological filters. The processed experimental results in testing steel samples demonstrate that these filters are capable of improving flaw detection in ultrasonic systems

  2. Digital image processing as a tool for pavement distress evaluation

    Science.gov (United States)

    Georgopoulos, A.; Loizos, A.; Flouda, A.

    The information obtained through accurate condition assessment of pavement surface distress data is needed as an essential input to any decision making process concerning pavement management policy. At the same time technological advances in automated inspection systems provide the opportunity to automate the collection and evaluation of the pavement surface condition. In this paper a method developed jointly by the Laboratories of Highway Engineering and Photogrammetry of the National Technical University of Athens is described and proposed. The method involves digital image processing techniques to provide suitable digital imagery as input to specialised software developed especially for this project. This software determines objectively and fully automatically the type, the extent and the severity of surface crackings for flexible road pavements. The proposed method presenten substantial agreement, when compared with systematic visual ratings of existing pavement crackings carried out according to the internationally accepted requirements for airfield and road pavement of the Federal Aviation Administration (FAA).

  3. Multidimensional evaluation processes to manage creative, resilient and sustainable city

    Directory of Open Access Journals (Sweden)

    Luigi Fusco Girard

    2011-12-01

    Full Text Available Multidimensional evaluation processes are considered as fundamental tools in managing the transition to the eco-city, toward a new ecological, urban and economic base, founded on synergies among three interdependent circuits of value creation: industrial economy, heritage economy and civil economy. The proposed approach can be a theoretical reference for next methodological and operative applications related to the port-city system, as example where the main contemporary contradictions/paradoxes come into being, and also the most suitable site where to reduce conflicts and transform them into synergies among creativity, resilience and sustainability for a human sustainable city.

  4. Digital image processing for diameter distribution evaluation of nuclear tracks

    International Nuclear Information System (INIS)

    Lira, J.; Camacho, S.; Balcazar-Garcia, M.; Peralta-Fabi, R.

    1984-01-01

    Fast reliable, and accurate evaluation of diameter distribution of nuclear tracks, etched on solid state nuclear detectors is necessary, to infer general information from the particular ions detected. To achieve this, it is primarily required to develop an on-line method, that is, a method fast enough so as the reading and information extraction processes became simultaneous. In order to accomplish this, adaptive matched filtering has been generalized to two dimensions; this lessens the noise content and the unwanted features present in the detector, and avoids distorting results significantly. (author)

  5. School-based vaccination: a systematic review of process evaluations.

    Science.gov (United States)

    Cooper Robbins, Spring Chenoa; Ward, Kirsten; Skinner, S Rachel

    2011-12-06

    School-based vaccination is becoming a more widely used method of vaccine delivery. However, evaluations of school-based vaccination program implementation have not been systematically reviewed. This paper describes the results of a systematic review of the literature on process (or implementation) evaluations of school-based vaccination delivery. Search terms: "school based vaccination" OR (("schools" OR "school") AND ("immunisation" OR "immunization" OR "vaccination")). Humans; English language; Age: 6-18 (school-age children and adolescents); No editorials; No letters. Databases: PUBMED; Embase.com; Cochrane Database of Systematic Reviews; Cinahl; Web of Science; PsycINFO. Inclusions: Articles must have originated from an advanced economic 'developed' country, be peer-reviewed, available in English, randomised or non-randomised controlled design, published from 1970 to August 2010 and focused on vaccinations provided in the school setting and during school time which reported one or more outcomes. qualitative or descriptive papers without any evaluation component; papers that only reported on impact evaluation (i.e. number of students vaccinated); and those published before 1970. A total of 14 articles were identified as including some element of a process evaluation of a school-based vaccination program. Nurses, parents, teachers, and adolescents were involved in measures of procedural factors related to school-based vaccination implementation. Outcomes included return rates of consent forms; knowledge about the specific vaccine offered; attitudes toward vaccination and school-based vaccination; reasons for non-vaccination; resources, support, and procedures related to implementation; and environmental factors within the school that may impact vaccination success. Vaccination coverage was also reported in the majority of papers. Many studies reported on the importance of ensuring all stakeholders (school nurses, parents, teachers, and adolescents) receive

  6. Evaluation of spinous process wiring techniques for accidental canal penetration.

    Science.gov (United States)

    Adeolu, Augustine A; Azeez, Abiodun L

    2013-04-01

    Accidental canal penetration with attendant complications constitutes one of the reasons for abandoning the use of wires for posterior spinal fusion techniques. However, there is dearth of information on this risk when the wire is introduced through the base of spinous process as against sublaminar passage. This study was designed to evaluate hardware-related postoperative complications, especially canal penetration, in our patients who had spinal process wiring in two types of posterior wiring techniques. Patients who had either of two spinous process wiring techniques formed the population for the study. The clinical records were reviewed and the following data were extracted: Age, sex, diagnosis, operation (fusion type), preoperative neurological status, postoperative neurologic deterioration, other postoperative complication and radiologic evidence of canal encroachment. One hundred and seventy four spinous processes were instrumented in 42 patients. The age of the patients ranged from 11 to 78 years while male to female ratio was 2.5:1. Majority of the spinal wiring were for trauma (29 patients; 69.0) while the remaining were tumor (6; 14.3%), degenerative diseases (4; 9.5%) and infections (3; 7.1%). The Rogers technique was performed in 16 (38.1%) patients while 26 (61.9%) underwent Adeolu et al. technique. One patient (2.3%) had neurologic deterioration while 5 patients (11.1%) had varying type of complications from wound infection to fracture of spinous processes. There was no patient with radiological or clinical evidence of canal compromise. Spinous process wiring techniques for posterior spinal stabilization appears to be safe as demonstrated in this study.

  7. Ecotoxicological, ecophysiological, and biogeochemical fundamentals of risk assessment

    International Nuclear Information System (INIS)

    Bashkin, V.N.; Kozlov, M.Ya.; Evstafjeva, E.V.

    1993-01-01

    Risk assessment (RA) influenced by different factors in radionuclide polluted regions is carried out by determining the biogeochemical structure of a region. Consequently, ecological-biogeochemical regionalization, ecotoxicological and ecophysiological monitoring of human population health are the important approach to RA. These criteria should conjugate with LCA of various industrial and agricultural products. Given fundamentals and approaches are needed for areas where traditional pollutants (heavy metals, pesticides, fertilizers, POPs etc) are enforced sharply by radioactive pollution. For RA of these complex pollutants, the methods of human adaptability to a polluted environment have been carried out. These techniques include biogeochemical, ecotoxicological, and ecophysiological analyses of risk factors as well as quantitative analysis of uncertainties using expert-modeling systems. Furthermore, the modern statistical methods are used for quantitative assessment of human adaptability to radioactive and nonradioactive pollutants. The results obtained in Chernobyl regions show the acceptability of these methods for risk assessment

  8. Evaluation process of global environmental impact: assessment guidelines

    International Nuclear Information System (INIS)

    Memon, A.R.; Mahar, R.B.

    2001-01-01

    In developed and developing countries, the EIA (Environmental Impact Assessment) is becoming mandatory for the approval of Industrial projects and projects of Environmental hazards. The approving authority of each country has its own guidelines to get projects approved and make project proponents responsible to submit Environmental Impact Statement for the its detailed assessment. In this paper authors have studied an existing EIA Global guidelines and its evaluation process of altogether 40 countries from four continents, Asia, Pacific/Middle East, Europe, Australia and America/Canada. This evaluation process is recorded in the tabulation form and it has been formulated stage wise in which stage one highlights the inception of EIA guidelines of each country and stage two and three gives implementation process. The inception stage of guidelines gives an idea that when EIA was started and an implementation stages provide all information that when EIA become a part of legislation that provide an opportunity to the reader to understand the decision making process for project approvals. The main objective of writing EIA guidelines is to monitor the sustain ability of various types of the projects under different sectoral guidelines, therefore Projects related with different Sectors have been chosen and a detailed record in tabulation form gives an idea to understand the interaction of these guidelines. To make this paper more comprehensive, authors have gone thorough the sectoral guidelines of altogether 64 countries and studied 21 sector oriented project fields. These are of Agriculture/Irrigation, Biodiversity, Coastal/Marine, Community Participation, Extractive industries, Fisheries, Forestry, Hazard Risk, Health, Human settlement, Industry, Multi sectorial, Ports and Harbors, Power, refugees/resettlement, Social, Strategies/Planning, Tourism/Recreational, transportation, Waste Pollution and Wetlands/Water resources. (author)

  9. An experimental evaluation of alarm processing and display characteristics

    International Nuclear Information System (INIS)

    O'Hara, J.; Brown, W.; Hallbert, B.; Skraaning, G.Jr.; Persensky, J.; Wachtel, J.

    1998-01-01

    This paper describes a research program sponsored by the U.S. Nuclear Regulatory Commission to address the human factors engineering (HFE) aspects of nuclear power plant alarm systems. The overall objective of the program is to develop HFE review guidance for advanced alarm systems. As part of this program, guidance has been developed based on a broad base of technical and research literature. In the course of guidance development, aspects of alarm system design for which the technical basis was insufficient to support complete guidance development were identified. The primary purpose of the research reported in this paper was to evaluate the effects of three of these alarm system design characteristics on operator performance in order to contribute to the understanding of potential safety issues and to provide data to support the development of design review guidance in these areas. Three alarm system design characteristics studied were (1) alarm processing (degree of alarm reduction), (2) alarm availability (dynamic prioritization and suppression), and (3) alarm display (a dedicated tile format, a mixed tile and message list format, and a format in which alarm information is integrated into the process displays). A secondary purpose was to provide confirmatory evidence of selected alarm system guidance developed in an earlier phase of the project. The alarm characteristics were combined into eight separate experimental conditions. Six, two-person crews of professional nuclear power plant operators participated in the study. Following training, each crew completed 16 test trials which consisted of two trials in each of the eight experimental conditions (one with a low-complexity scenario and one with a high-complexity scenario). Measures of process performance. operator task performance, situation awareness, and workload were obtained. In addition. operator opinions and evaluations of the alarm processing and display conditions were collected. Numerous strengths

  10. Sodium dichromate as a process water additive: An evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Lutton, J.M.

    1953-03-19

    For several years-after the start-up of the Hanford Piles, little concern was felt for the quality of process water. Techniques developed by CMX and improved in the course of operating experience were substantially successful for controlling and removing pressure drop film; and corru%ion rates at the early power levels were uniformly low and not a matter of concern, particularly since slugs were not exposed for more than 250 MWD/ton. As power and exposure levels were drastically increased, however, corrosion rates began to become serious and now threaten to limit future increases. Whether or not corrosion was causing these latter problems, it was clearly imperative to seek ways to reduce the corrobivity of the water. It was recognized that subtantial savings could be made by the elimination of sodium dichromate as a process water additive. Since the rather high pH of process water was neceasary primarily to prevent dichromate reduction, the way would then be open for reducing the pH, and it was hoped that this would improve in-pile corrosion and materially reduce water treatment costs. There is a large amount of data in the project literature pertaining to the dichromate problem, and it seemed urgent in view of recent experiences to re-evaluate this information to learn whether the issues might not be clarified and firm conclusions reached. This document presents such a re-evaluation and drawn conclusions which pending the completion of experiments now in progress, will serve as a primary basis for technical recommendations concerning dichromate addition to process water at all existing 100 areas and at the 100-K areas now under construction.

  11. Quality Evaluation of Processed Products of some Peach Varieties

    Directory of Open Access Journals (Sweden)

    Gheorghe Lămureanu

    2015-11-01

    Full Text Available The peach tree is among one of the most valuable species cultivated both in Romania and abroad, being very much appreciated for the quality of its fruit, both fresh and processed.  The peach tree provides fresh fruit a large period (June-November. This allows for a rhythmical and prolonged supply with fresh fruit of the factories that process fruits. This paper has as purpose the establishing of the viability for processing into stewed fruit, comfiture, jam and nectar of nine varieties of peach: Catherine, Mimi, Southland, Narajnai ramai, Royal vee, Filip, Redhaven, Raluca and Collins. The peaches, provided from experimental plots of Research Station for Fruit Growing Constanta, were processed in micro production laboratory of Research Institute for Processing of the Horticultural Products, Bucharest. The sensorial analysis of the product was carried out according to the STAS 12656-88, which establishes the analysis methods with unitary scales of points (method A, methods used in the evaluation of the organoleptic characteristics of alimentary products. These methods are applied in order to appreciate a set of organoleptic properties: aspect, colour, taste, texture or consistence. Among the nine varieties of fruits peach was highlighting the variety Narajnai ramai, which recieved maximum score (20.00 points for comfiture and jam and a total average score of 19.88 for stewed fruits and 19.77 for nectar. This variety, together with the varieties Mimi and Catherine  obtained the score “very good” for all four types of canned analyzed: comfiture, jam, compote and nectar. The worse results were obtained by the variety Collins, which is less suitable for processing. After organoleptic testing, it received the score “good” for products comfiture and jam and the score “satisfactory” for products nectar and stewed fruits. The results presented in this  research work showed that the organoleptic characteristics of fresh fruits influences

  12. Process Evaluation of a Workers' Health Surveillance Program for Meat Processing Workers.

    Science.gov (United States)

    van Holland, Berry J; Brouwer, Sandra; de Boer, Michiel R; Reneman, Michiel F; Soer, Remko

    2017-09-01

    Objective To evaluate the implementation process of a workers' health surveillance (WHS) program in a Dutch meat processing company. Methods Workers from five plants were eligible to participate in the WHS program. The program consisted of four evaluative components and an intervention component. Qualitative and quantitative methods were used to evaluate seven process aspects. Data were gathered by interviews with stakeholders, participant questionnaires, and from registries of the company and occupational health service. Results Two recruitment strategies were used: open invitation or automatic participation. Of the 986 eligible workers, 305 participated in the program. Average reach was 53 %. Two out of five program components could not be assessed on dose delivered, dose received and fidelity. If components were assessable, 85-100 % of the components was delivered, 66-100 % of the components was received by participants, and fidelity was 100 %. Participants were satisfied with the WHS program (mean score 7.6). Contextual factors that facilitated implementation were among others societal developments and management support. Factors that formed barriers were program novelty and delayed follow-up. Conclusion The WHS program was well received by participants. Not all participants were offered the same number of program components, and not all components were performed according to protocol. Deviation from protocol is an indication of program failure and may affect program effectiveness.

  13. Morphological, hydrological, biogeochemical and ecological changes and challenges in river restoration - the Thur River case study

    Science.gov (United States)

    Schirmer, M.; Luster, J.; Linde, N.; Perona, P.; Mitchell, E. A. D.; Barry, D. A.; Hollender, J.; Cirpka, O. A.; Schneider, P.; Vogt, T.; Radny, D.; Durisch-Kaiser, E.

    2014-06-01

    River restoration can enhance river dynamics, environmental heterogeneity and biodiversity, but the underlying processes governing the dynamic changes need to be understood to ensure that restoration projects meet their goals, and adverse effects are prevented. In particular, we need to comprehend how hydromorphological variability quantitatively relates to ecosystem functioning and services, biodiversity as well as ground- and surface water quality in restored river corridors. This involves (i) physical processes and structural properties, determining erosion and sedimentation, as well as solute and heat transport behavior in surface water and within the subsurface; (ii) biogeochemical processes and characteristics, including the turnover of nutrients and natural water constituents; and (iii) ecological processes and indicators related to biodiversity and ecological functioning. All these aspects are interlinked, requiring an interdisciplinary investigation approach. Here, we present an overview of the recently completed RECORD (REstored CORridor Dynamics) project in which we combined physical, chemical, and biological observations with modeling at a restored river corridor of the perialpine Thur River in Switzerland. Our results show that river restoration, beyond inducing morphologic changes that reshape the river bed and banks, triggered complex spatial patterns of bank infiltration, and affected habitat type, biotic communities and biogeochemical processes. We adopted an interdisciplinary approach of monitoring the continuing changes due to restoration measures to address the following questions: How stable is the morphological variability established by restoration? Does morphological variability guarantee an improvement in biodiversity? How does morphological variability affect biogeochemical transformations in the river corridor? What are some potential adverse effects of river restoration? How is river restoration influenced by catchment-scale hydraulics

  14. Physical activity across the curriculum: year one process evaluation results

    Directory of Open Access Journals (Sweden)

    Sullivan Debra K

    2008-07-01

    Full Text Available Abstract Background Physical Activity Across the Curriculum (PAAC is a 3-year elementary school-based intervention to determine if increased amounts of moderate intensity physical activity performed in the classroom will diminish gains in body mass index (BMI. It is a cluster-randomized, controlled trial, involving 4905 children (2505 intervention, 2400 control. Methods We collected both qualitative and quantitative process evaluation data from 24 schools (14 intervention and 10 control, which included tracking teacher training issues, challenges and barriers to effective implementation of PAAC lessons, initial and continual use of program specified activities, and potential competing factors, which might contaminate or lessen program effects. Results Overall teacher attendance at training sessions showed exceptional reach. Teachers incorporated active lessons on most days, resulting in significantly greater student physical activity levels compared to controls (p Conclusion In the first year of the PAAC intervention, process evaluation results were instrumental in identifying successes and challenges faced by teachers when trying to modify existing academic lessons to incorporate physical activity.

  15. Economic evaluation of radiation processing in urban solid wastes treatment

    Science.gov (United States)

    Carassiti, F.; Lacquaniti, L.; Liuzzo, G.

    During the last few years, quite a number of studies have been done, or are still in course, on disinfection of urban liquid wastes by means of ionizing radiations. The experience gained by SANDIA pilot plant of irradiation on dried sewage sludge, together with the recently presented conceptual design of another plant handling granular solids, characterized by high efficiency and simple running, have shown the possibility of extending this process to the treatment of urban solid wastes. As a matter of fact, the problems connected to the pathogenic aspects of sludge handling are often similar to those met during the disposal of urban solid wastes. This is even more so in the case of their reuse in agriculture and zootechny. The present paper introduces the results of an analysis carried out in order to evaluate the economical advantage of inserting irradiation treatment in some process scheme for management of urban solid wastes. Taking as an example a comprehensive pattern of urban solid wastes management which has been analysed and estimated economically in previous works, we first evaluated the extra capital and operational costs due to the irradiation and then analysed economical justification, taking into account the increasing commercial value of the by-products.

  16. Automating the Human Factors Engineering and Evaluation Processes

    International Nuclear Information System (INIS)

    Mastromonico, C.

    2002-01-01

    The Westinghouse Savannah River Company (WSRC) has developed a software tool for automating the Human Factors Engineering (HFE) design review, analysis, and evaluation processes. The tool provides a consistent, cost effective, graded, user-friendly approach for evaluating process control system Human System Interface (HSI) specifications, designs, and existing implementations. The initial set of HFE design guidelines, used in the tool, was obtained from NUREG- 0700. Each guideline was analyzed and classified according to its significance (general concept vs. supporting detail), the HSI technology (computer based vs. non-computer based), and the HSI safety function (safety vs. non-safety). Approximately 10 percent of the guidelines were determined to be redundant or obsolete and were discarded. The remaining guidelines were arranged in a Microsoft Access relational database, and a Microsoft Visual Basic user interface was provided to facilitate the HFE design review. The tool also provides the capability to add new criteria to accommodate advances in HSI technology and incorporate lessons learned. Summary reports produced by the tool can be easily ported to Microsoft Word and other popular PC office applications. An IBM compatible PC with Microsoft Windows 95 or higher is required to run the application

  17. Identifying and Evaluating Chaotic Behavior in Hydro-Meteorological Processes

    Directory of Open Access Journals (Sweden)

    Soojun Kim

    2015-01-01

    Full Text Available The aim of this study is to identify and evaluate chaotic behavior in hydro-meteorological processes. This study poses the two hypotheses to identify chaotic behavior of the processes. First, assume that the input data is the significant factor to provide chaotic characteristics to output data. Second, assume that the system itself is the significant factor to provide chaotic characteristics to output data. For solving this issue, hydro-meteorological time series such as precipitation, air temperature, discharge, and storage volume were collected in the Great Salt Lake and Bear River Basin, USA. The time series in the period of approximately one year were extracted from the original series using the wavelet transform. The generated time series from summation of sine functions were fitted to each series and used for investigating the hypotheses. Then artificial neural networks had been built for modeling the reservoir system and the correlation dimension was analyzed for the evaluation of chaotic behavior between inputs and outputs. From the results, we found that the chaotic characteristic of the storage volume which is output is likely a byproduct of the chaotic behavior of the reservoir system itself rather than that of the input data.

  18. Evaluation of feeds for melt and dilute process using an analytical hierarchy process

    International Nuclear Information System (INIS)

    Krupa, J.F.

    2000-01-01

    Westinghouse Savannah River Company was requested to evaluate whether nuclear materials other than aluminum-clad spent nuclear fuel should be considered for treatment to prepare them for disposal in the melt and dilute facility as part of the Treatment and Storage Facility currently projected for construction in the L-Reactor process area. The decision analysis process used to develop this analysis considered many variables and uncertainties, including repository requirements that are not yet finalized. The Analytical Hierarchy Process using a ratings methodology was used to rank potential feed candidates for disposition through the Melt and Dilute facility proposed for disposition of Savannah River Site aluminum-clad spent nuclear fuel. Because of the scoping nature of this analysis, the expert team convened for this purpose concentrated on technical feasibility and potential cost impacts associated with using melt and dilute versus the current disposition option. This report documents results of the decision analysis

  19. Evaluation of feeds for melt and dilute process using an analytical hierarchy process

    Energy Technology Data Exchange (ETDEWEB)

    Krupa, J.F.

    2000-03-22

    Westinghouse Savannah River Company was requested to evaluate whether nuclear materials other than aluminum-clad spent nuclear fuel should be considered for treatment to prepare them for disposal in the melt and dilute facility as part of the Treatment and Storage Facility currently projected for construction in the L-Reactor process area. The decision analysis process used to develop this analysis considered many variables and uncertainties, including repository requirements that are not yet finalized. The Analytical Hierarchy Process using a ratings methodology was used to rank potential feed candidates for disposition through the Melt and Dilute facility proposed for disposition of Savannah River Site aluminum-clad spent nuclear fuel. Because of the scoping nature of this analysis, the expert team convened for this purpose concentrated on technical feasibility and potential cost impacts associated with using melt and dilute versus the current disposition option. This report documents results of the decision analysis.

  20. Evaluation of Brine Processing Technologies for Spacecraft Wastewater

    Science.gov (United States)

    Shaw, Hali L.; Flynn, Michael; Wisniewski, Richard; Lee, Jeffery; Jones, Harry; Delzeit, Lance; Shull, Sarah; Sargusingh, Miriam; Beeler, David; Howard, Jeanie; hide

    2015-01-01

    Brine drying systems may be used in spaceflight. There are several advantages to using brine processing technologies for long-duration human missions including a reduction in resupply requirements and achieving high water recovery ratios. The objective of this project was to evaluate four technologies for the drying of spacecraft water recycling system brine byproducts. The technologies tested were NASA's Forward Osmosis Brine Drying (FOBD), Paragon's Ionomer Water Processor (IWP), NASA's Brine Evaporation Bag (BEB) System, and UMPQUA's Ultrasonic Brine Dewatering System (UBDS). The purpose of this work was to evaluate the hardware using feed streams composed of brines similar to those generated on board the International Space Station (ISS) and future exploration missions. The brine formulations used for testing were the ISS Alternate Pretreatment and Solution 2 (Alt Pretreat). The brines were generated using the Wiped-film Rotating-disk (WFRD) evaporator, which is a vapor compression distillation system that is used to simulate the function of the ISS Urine Processor Assembly (UPA). Each system was evaluated based on the results from testing and Equivalent System Mass (ESM) calculations. A Quality Function Deployment (QFD) matrix was also developed as a method to compare the different technologies based on customer and engineering requirements.

  1. Optimizing the post-graduate institutional program evaluation process.

    Science.gov (United States)

    Lypson, Monica L; Prince, Mark E P; Kasten, Steven J; Osborne, Nicholas H; Cohan, Richard H; Kowalenko, Terry; Dougherty, Paul J; Reynolds, R Kevin; Spires, M Catherine; Kozlow, Jeffrey H; Gitlin, Scott D

    2016-02-17

    Reviewing program educational efforts is an important component of postgraduate medical education program accreditation. The post-graduate review process has evolved over time to include centralized oversight based on accreditation standards. The institutional review process and the impact on participating faculty are topics not well described in the literature. We conducted multiple Plan-Do-Study-Act (PDSA) cycles to identify and implement areas for change to improve productivity in our institutional program review committee. We also conducted one focus group and six in-person interviews with 18 committee members to explore their perspectives on the committee's evolution. One author (MLL) reviewed the transcripts and performed the initial thematic coding with a PhD level research associate and identified and categorized themes. These themes were confirmed by all participating committee members upon review of a detailed summary. Emergent themes were triangulated with the University of Michigan Medical School's Admissions Executive Committee (AEC). We present an overview of adopted new practices to the educational program evaluation process at the University of Michigan Health System that includes standardization of meetings, inclusion of resident members, development of area content experts, solicitation of committed committee members, transition from paper to electronic committee materials, and focus on continuous improvement. Faculty and resident committee members identified multiple improvement areas including the ability to provide high quality reviews of training programs, personal and professional development, and improved feedback from program trainees. A standing committee that utilizes the expertise of a group of committed faculty members and which includes formal resident membership has significant advantages over ad hoc or other organizational structures for program evaluation committees.

  2. How do persistent organic pollutants be coupled with biogeochemical cycles of carbon and nutrients in terrestrial ecosystems under global climate change?

    Energy Technology Data Exchange (ETDEWEB)

    Teng, Ying [Chinese Academy of Sciences, Nanjing (China). Key Lab. of Soil Environment and Pollution Remediation; Griffith Univ., Nathan, QLD (Australia). Environmetnal Futures Centre and School of Biomolecular and Physical Sciences; Xu, Zhihong; Reverchon, Frederique [Griffith Univ., Nathan, QLD (Australia). Environmetnal Futures Centre and School of Biomolecular and Physical Sciences; Luo, Yongming [Chinese Academy of Sciences, Nanjing (China). Key Lab. of Soil Environment and Pollution Remediation

    2012-03-15

    Global climate change (GCC), especially global warming, has affected the material cycling (e.g., carbon, nutrients, and organic chemicals) and the energy flows of terrestrial ecosystems. Persistent organic pollutants (POPs) were regarded as anthropogenic organic carbon (OC) source, and be coupled with the natural carbon (C) and nutrient biogeochemical cycling in ecosystems. The objective of this work was to review the current literature and explore potential coupling processes and mechanisms between POPs and biogeochemical cycles of C and nutrients in terrestrial ecosystems induced by global warming. Global warming has caused many physical, chemical, and biological changes in terrestrial ecosystems. POPs environmental fate in these ecosystems is controlled mainly by temperature and biogeochemical processes. Global warming may accelerate the re-emissions and redistribution of POPs among environmental compartments via soil-air exchange. Soil-air exchange is a key process controlling the fate and transportation of POPs and terrestrial ecosystem C at regional and global scales. Soil respiration is one of the largest terrestrial C flux induced by microbe and plant metabolism, which can affect POPs biotransformation in terrestrial ecosystems. Carbon flow through food web structure also may have important consequences for the biomagnification of POPs in the ecosystems and further lead to biodiversity loss induced by climate change and POPs pollution stress. Moreover, the integrated techniques and biological adaptation strategy help to fully explore the coupling mechanisms, functioning and trends of POPs and C and nutrient biogeochemical cycling processes in terrestrial ecosystems. There is increasing evidence that the environmental fate of POPs has been linked with biogeochemical cycles of C and nutrients in terrestrial ecosystems under GCC. However, the relationships between POPs and the biogeochemical cycles of C and nutrients are still not well understood. Further

  3. Strategy, Performance Evaluation and Process Management in Higher Education Institutions

    Directory of Open Access Journals (Sweden)

    Sabrina Letícia Couto da Silva

    2017-06-01

    Full Text Available The processes of Strategic Planning (SP, Performance Evaluation (PE and Process Management (PM for Higher Education Institutions (HEI are considered more than ever, urgent and necessary, acting as the factors of motivation, awareness and exploratory data collection. The objective of this paper is to identify positive and negative aspects involved in realization of SP, PE and PM in HEI, through a literature review. The study was exploratory and descriptive, accomplished through a bibliographic review in online data bases. It was possible to identify that HEI are considered complex systems which results in implications on execution of the SP, PE and PM. Apart from that, it was identified barriers in the literature, being the main ones: decentralization, autonomy of departments, heterogeneity in the operation of departments, data stored in places that cannot be accessed by everybody, bureaucracy, resistance to change, dissociation between planning and management, lack of participation of university community in the process of planning. It was also found ways to overcome these barriers being the main ones: commitment of high management, clear strategy, wide communication and participation of all people involved.

  4. The evaluation framework for business process management methodologies

    Directory of Open Access Journals (Sweden)

    Sebastian Lahajnar

    2016-06-01

    Full Text Available In an intense competition in the global market, organisations seek to take advantage of all their internal and external potentials, advantages, and resources. It has been found that, in addition to competitive products and services, a good business also requires an effective management of business processes, which is the discipline of the business process management (BPM. The introduction of the BPM in the organisation requires a thoughtful selection of an appropriate methodological approach, since the latter will formalize activities, products, applications and other efforts of the organisation in this field. Despite many technology-driven solutions of software companies, recommendations of consulting companies, techniques, good practices and tools, the decision on what methodology to choose is anything but simple. The aim of this article is to simplify the adoption of such decisions by building a framework for the evaluation of BPM methodologies according to a qualitative multi-attribute decision-making method. The framework defines a hierarchical decision-making model, formalizes the decision-making process and thus contributes significantly to an independent, credible final decision that is the most appropriate for a specific organisation.

  5. Classification and Quality Evaluation of Tobacco Leaves Based on Image Processing and Fuzzy Comprehensive Evaluation

    Science.gov (United States)

    Zhang, Fan; Zhang, Xinhong

    2011-01-01

    Most of classification, quality evaluation or grading of the flue-cured tobacco leaves are manually operated, which relies on the judgmental experience of experts, and inevitably limited by personal, physical and environmental factors. The classification and the quality evaluation are therefore subjective and experientially based. In this paper, an automatic classification method of tobacco leaves based on the digital image processing and the fuzzy sets theory is presented. A grading system based on image processing techniques was developed for automatically inspecting and grading flue-cured tobacco leaves. This system uses machine vision for the extraction and analysis of color, size, shape and surface texture. Fuzzy comprehensive evaluation provides a high level of confidence in decision making based on the fuzzy logic. The neural network is used to estimate and forecast the membership function of the features of tobacco leaves in the fuzzy sets. The experimental results of the two-level fuzzy comprehensive evaluation (FCE) show that the accuracy rate of classification is about 94% for the trained tobacco leaves, and the accuracy rate of the non-trained tobacco leaves is about 72%. We believe that the fuzzy comprehensive evaluation is a viable way for the automatic classification and quality evaluation of the tobacco leaves. PMID:22163744

  6. Vadose zone attenuation of organic compounds at a crude oil spill site - Interactions between biogeochemical reactions and multicomponent gas transport

    Science.gov (United States)

    Molins, S.; Mayer, K.U.; Amos, R.T.; Bekins, B.A.

    2010-01-01

    Contaminant attenuation processes in the vadose zone of a crude oil spill site near Bemidji, MN have been simulated with a reactive transport model that includes multicomponent gas transport, solute transport, and the most relevant biogeochemical reactions. Dissolution and volatilization of oil components, their aerobic and anaerobic degradation coupled with sequential electron acceptor consumption, ingress of atmospheric O2, and the release of CH4 and CO2 from the smear zone generated by the floating oil were considered. The focus of the simulations was to assess the dynamics between biodegradation and gas transport processes in the vadose zone, to evaluate the rates and contributions of different electron accepting processes towards vadose zone natural attenuation, and to provide an estimate of the historical mass loss. Concentration distributions of reactive (O2, CH4, and CO2) and non-reactive (Ar and N2) gases served as key constraints for the model calibration. Simulation results confirm that as of 2007, the main degradation pathway can be attributed to methanogenic degradation of organic compounds in the smear zone and the vadose zone resulting in a contaminant plume dominated by high CH4 concentrations. In accordance with field observations, zones of volatilization and CH4 generation are correlated to slightly elevated total gas pressures and low partial pressures of N2 and Ar, while zones of aerobic CH4 oxidation are characterized by slightly reduced gas pressures and elevated concentrations of N2 and Ar. Diffusion is the most significant transport mechanism for gases in the vadose zone; however, the simulations also indicate that, despite very small pressure gradients, advection contributes up to 15% towards the net flux of CH4, and to a more limited extent to O2 ingress. Model calibration strongly suggests that transfer of biogenically generated gases from the smear zone provides a major control on vadose zone gas distributions and vadose zone carbon

  7. Biogeochemical stability and reactions of iron-organic carbon complexes

    Science.gov (United States)

    Yang, Y.; Adhikari, D.; Zhao, Q.; Dunham-Cheatham, S.; Das, K.; Mejia, J.; Huang, R.; Wang, X.; Poulson, S.; Tang, Y.; Obrist, D.; Roden, E. E.

    2017-12-01

    Our core hypothesis is that the degradation rate of soil organic carbon (OC) is governed by the amount of iron (Fe)-bound OC, and the ability of microbial communities to utilize OC as an energy source and electron shuttle for Fe reduction that in turn stimulates reductive release of Fe-bound labile dissolved OC. This hypothesis is being systematically evaluated using model Fe-OC complexes, natural soils, and microcosm system. We found that hematite-bound aliphatic C was more resistant to reduction release, although hematite preferred to sorb more aromatic C. Resistance to reductive release represents a new mechanism that aliphatic soil OC was stabilized by association with Fe oxide. In other studies, pyrogenic OC was found to facilitate the reduction of hematite, by enhancing extracellular electron transport and sorbing Fe(II). For ferrihydrite-OC co-precipitates, the reduction of Fe and release of OC was closely governed by the C/Fe ratio in the system. Based on the XPS, XANES and XAFS analysis, the transformation of Fe speciation was heterogeneous, depending on the conformation and composition of Fe-OC complexes. For natural soils, we investigated the quantity, characteristics, and reactivity of Fe-bound OC in soils collected from 14 forests in the United States. Fe-bound OC contributed up to 57.8% of total OC in the forest soils. Under the anaerobic conditions, the reduction of Fe was positively correlated to the electron accepting capacity of OC. Our findings highlight the closely coupled dynamics of Fe and OC, with broad implications on the turnover of OC and biogeochemical cycles of Fe.

  8. Intra- versus inter-site macroscale variation in biogeochemical properties along a paddy soil chronosequence

    Directory of Open Access Journals (Sweden)

    C. Mueller-Niggemann

    2012-03-01

    Full Text Available In order to assess the intrinsic heterogeneity of paddy soils, a set of biogeochemical soil parameters was investigated in five field replicates of seven paddy fields (50, 100, 300, 500, 700, 1000, and 2000 yr of wetland rice cultivation, one flooded paddy nursery, one tidal wetland (TW, and one freshwater site (FW from a coastal area at Hangzhou Bay, Zhejiang Province, China. All soils evolved from a marine tidal flat substrate due to land reclamation. The biogeochemical parameters based on their properties were differentiated into (i a group behaving conservatively (TC, TOC, TN, TS, magnetic susceptibility, soil lightness and colour parameters, δ13C, δ15N, lipids and n-alkanes and (ii one encompassing more labile properties or fast cycling components (Nmic, Cmic, nitrate, ammonium, DON and DOC. The macroscale heterogeneity in paddy soils was assessed by evaluating intra- versus inter-site spatial variability of biogeochemical properties using statistical data analysis (descriptive, explorative and non-parametric. Results show that the intrinsic heterogeneity of paddy soil organic and minerogenic components per field is smaller than between study sites. The coefficient of variation (CV values of conservative parameters varied in a low range (10% to 20%, decreasing from younger towards older paddy soils. This indicates a declining variability of soil biogeochemical properties in longer used cropping sites according to progress in soil evolution. A generally higher variation of CV values (>20–40% observed for labile parameters implies a need for substantially higher sampling frequency when investigating these as compared to more conservative parameters. Since the representativeness of the sampling strategy could be sufficiently demonstrated, an investigation of long-term carbon accumulation/sequestration trends in topsoils of the 2000 yr paddy chronosequence under wetland rice cultivation

  9. Long-term ERT monitoring of biogeochemical changes of an aged hydrocarbon contamination

    Science.gov (United States)

    Caterina, David; Flores Orozco, Adrian; Nguyen, Frédéric

    2017-06-01

    Adequate management of contaminated sites requires information with improved spatio-temporal resolution, in particular to assess bio-geochemical processes, such as the transformation and degradation of contaminants, precipitation of minerals or changes in groundwater geochemistry occurring during and after remediation procedures. Electrical Resistivity Tomography (ERT), a geophysical method sensitive to pore-fluid and pore-geometry properties, permits to gain quasi-continuous information about subsurface properties in real-time and has been consequently widely used for the characterization of hydrocarbon-impacted sediments. However, its application for the long-term monitoring of processes accompanying natural or engineered bioremediation is still difficult due to the poor understanding of the role that biogeochemical processes play in the electrical signatures. For in-situ studies, the task is further complicated by the variable signal-to-noise ratio and the variations of environmental parameters leading to resolution changes in the electrical images. In this work, we present ERT imaging results for data collected over a period of two years on a site affected by a diesel fuel contamination and undergoing bioremediation. We report low electrical resistivity anomalies in areas associated to the highest contaminant concentrations likely due transformations of the contaminant due to microbial activity and accompanying release of metabolic products. We also report large seasonal variations of the bulk electrical resistivity in the contaminated areas in correlation with temperature and groundwater level fluctuations. However, the amplitude of bulk electrical resistivity variations largely exceeds the amplitude expected given existing petrophysical models. Our results suggest that the variations in electrical properties are mainly controlled by microbial activity which in turn depends on soil temperature and hydrogeological conditions. Therefore, ERT can be suggested as

  10. Biogeochemical cycling at the aquatic-terrestrial interface is linked to parafluvial hyporheic zone inundation history

    Science.gov (United States)

    Goldman, Amy E.; Graham, Emily B.; Crump, Alex R.; Kennedy, David W.; Romero, Elvira B.; Anderson, Carolyn G.; Dana, Karl L.; Resch, Charles T.; Fredrickson, Jim K.; Stegen, James C.

    2017-09-01

    , the microbial community adapts to saturation by shifting composition, and the CO2 flux rebounds to prior levels due to the subsequent change in respiration. Our results indicate that the time between inundation events can push the system into alternate states: we suggest (i) that, above some threshold of inundation interval, re-inundation suppresses respiration to a consistent, low rate and (ii) that, below some inundation interval, re-inundation has a minor effect on respiration. Extending reactive transport models to capture processes that govern such dynamics will provide more robust predictions of river corridor biogeochemical function under altered surface water flow regimes in both managed and natural watersheds.

  11. Concentration of BSA using a superabsorbent polymer: process evaluation.

    Science.gov (United States)

    Prazeres, D M

    1995-04-15

    A commercially available super absorbent polymer from Hoechst (Sanwet IM-5000-SG) was tested for the concentration of dilute solutions of bovine serum albumin (BSA). A systematic study was undertaken in order to evaluate the possibility of scaling-up the process. The polymer was first characterized by determining the swelling ratio (or mass increase) in aqueous solution as a function of time, temperature, pH, salt and polymer concentration. The swelling ratio was found to be independent of the polymer concentration, temperature (range 15-50 degree C), and pH (range 4-10), but decreased significantly with an increase in NaCL concentration. The polymer was capable of absorbing as much as 300-times its own weight in water, when using the most favorable conditions (0 mM NaCL). BSA was concentrated up to 3.5-times when using the appropriate polymer concentration. The recovery of protein was around 100% for concentration factors below 2.0, but decreased for higher concentration factors. As expected from the characterization results, higher amounts of polymer were needed to concentrate BSA solutions with higher salt concentrations. The performance of the process improved when using lower concentration BSA solutions (0.15 to 0.5 mg ml-1). The initial volume (10 to 500 ml) had a slight effect on the process due to a decrease in the rate of the absorption process. The concentration factor was predicted from the NaCL and polymer concentrations through a semi empirical model.

  12. Evaluating the implementation process of a participatory organization level occupational health intervention in schools.

    NARCIS (Netherlands)

    Schelvis, R.M.C.; Wiezer, Noortje M.; Blatter, Birgit M.; van Genabeek, Joost A.G.M.; Oude Hengel, Karen M.; Bohlmeijer, Ernst Thomas; van der Beek, A.J.

    2016-01-01

    Background The importance of process evaluations in examining how and why interventions are (un) successful is increasingly recognized. Process evaluations mainly studied the implementation process and the quality of the implementation (fidelity). However, in adopting this approach for participatory

  13. Evaluating the implementation process of a participatory organizational level occupational health intervention in schools

    NARCIS (Netherlands)

    Schelvis, R.M.C.; Wiezer, N.M.; Blatter, B.M.; Genabeek, J.A.G.M. van; Oude Hengel, K.M.; Bohlneijer, E.T.; Beek, A.J. van der

    2016-01-01

    Background The importance of process evaluations in examining how and why interventions are (un) successful is increasingly recognized. Process evaluations mainly studied the implementation process and the quality of the implementation (fidelity). However, in adopting this approach for participatory

  14. The prioritization and categorization method (PCM) process evaluation at Ericsson : a case study

    NARCIS (Netherlands)

    Ohlsson, Jens; Han, Shengnan; Bouwman, W.A.G.A.

    2017-01-01

    Purpose: The purpose of this paper is to demonstrate and evaluate the prioritization and categorization method (PCM), which facilitates the active participation of process stakeholders (managers, owners, customers) in process assessments. Stakeholders evaluate processes in terms of effectiveness,

  15. Process evaluation of the Regional Biomass Energy Program

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, C.R.; Brown, M.A.; Perlack, R.D.

    1994-03-01

    The U.S. Department of Energy (DOE) established the Regional Biomass Energy Program (RBEP) in 1983 to increase the production and use of biomass energy resources. Through the creation of five regional program (the Great Lakes, Northeast, Pacific Northwest, Southeast, and West), the RBEP focuses on regionally specific needs and opportunities. In 1992, Oak Ridge National (ORNL) conducted a process evaluation of the RBEP Program designed to document and explain the development of the goals and strategies of the five regional programs; describe the economic and market context surrounding commercialization of bioenergy systems; assess the criteria used to select projects; describe experiences with cost sharing; identify program accomplishments in the transfer of information and technology; and offer recommendations for program improvement.

  16. Preliminary process engineering evaluation of ethanol production from vegetative crops

    Science.gov (United States)

    Moreira, A. R.; Linden, J. C.; Smith, D. H.; Villet, R. H.

    1982-12-01

    Vegetative crops show good potential as feedstock for ethanol production via cellulose hydrolysis and yeast fermentation. The low levels of lignin encountered in young plant tissues show an inverse relationship with the high cellulose digestibility during hydrolysis with cellulose enzymes. Ensiled sorghum species and brown midrib mutants of sorghum exhibit high glucose yields after enzyme hydrolysis as well. Vegetative crop materials as candidate feedstocks for ethanol manufacture should continue to be studied. The species studied so far are high value cash crops and result in relatively high costs for the final ethanol product. Unconventional crops, such as pigweed, kochia, and Russian thistle, which can use water efficiently and grow on relatively arid land under conditions not ideal for food production, should be carefully evaluated with regard to their cultivation requirements, photosynthesis rates, and cellulose digestibility. Such crops should result in more favorable process economics for alcohol production.

  17. The Amazon region: tropical deforestation, biogeochemical cycles and the climate

    NARCIS (Netherlands)

    Kabat, P.; Andreae, M.O.; Silva-Dias, M.A.; Veraart, J.A.; Brink, N.J.

    2003-01-01

    The biogeochemical cycling of carbon, water, energy, aerosols, and trace gases in the Amazon Basin, and the interactions between deforestation, rainfall and climate were all investigated in this programme as a part of an integrated cluster of inter-linked and complementary research projects. These

  18. Ecogenomics and potential biogeochemical impacts of globally abundant ocean viruses

    NARCIS (Netherlands)

    Roux, S.; Brum, J.R.; Dutilh, B.E.; Sunagawa, S.; Duhaime, M.B.; Loy, A.; Poulos, B.T.; Solonenko, N.; Lara, E.; Poulain, J.; Pesant, S.; Kandels-Lewis, S.; Dimier, C.; Picheral, M.; Searson, S.; Cruaud, C.; Alberti, A.; Duarte, C.M.; Gasol, J.M.; Vaque, D.; Bork, P.; Acinas, S.G.; Wincker, P.; Sullivan, M.B.

    2016-01-01

    Ocean microbes drive biogeochemical cycling on a global scale. However, this cycling is constrained by viruses that affect community composition, metabolic activity, and evolutionary trajectories. Owing to challenges with the sampling and cultivation of viruses, genome-level viral diversity remains

  19. Empathy Modulates the Evaluation Processing of Altruistic Outcomes

    Directory of Open Access Journals (Sweden)

    Xin Liu

    2018-04-01

    Full Text Available Empathy plays a central role in social decisions involving psychological conflict, such as whether to help another person at the cost of one’s own interests. Using the event-related potential (ERP technique, the current study explored the neural mechanisms underlying the empathic effect on the evaluation processing of outcomes in conflict-of-interest situations, in which the gain of others resulted in the performer’s loss. In the high-empathy condition, the beneficiaries were underprivileged students who were living in distress (stranger in need. In the low-empathy condition, the beneficiaries were general students without miserable information (stranger not in need. ERP results showed that the FRN was more negative-going for self no-gain than self gain, but showed reversed pattern for other’s outcome (i.e., more negative for gain than no-gain in the low-empathy condition, indicating that participants interpreted the gain of others as the loss of themselves. However, the reversed FRN pattern was not observed in the high-empathy condition, suggesting that the neural responses to one’s own loss are buffered by empathy. In addition, the P3 valence effect was observed only in the self condition, but not in the two stranger conditions, indicating that the P3 is more sensitive to self-relevant information. Moreover, the results of subjective rating showed that more empathic concern and altruistic motivation were elicited in the high-empathy condition than in the low-empathy condition, and these scores had negative linear correlations only with the FRN, but not with the P3. These findings suggest that when outcomes following altruistic decisions involve conflict of interest, the early stage of the processing of outcome evaluation could be modulated by the empathic level.

  20. Evaluation of an accelerated mineralization process for ashes - feasibility study; Evaluering av jordmaansbildande askbehandlingsprocess (EJA) - foerstudie

    Energy Technology Data Exchange (ETDEWEB)

    Ecke, Holger; Bjurstroem, Henrik

    2005-03-01

    In Japan, expenses for landfilling yield about 400 USD per ton of ash, which gives an incentive to reduce the amount of landfilled ash. At NIES (National Institute for Environmental Studies) in Tsukuba, Japan, the AMT process (Accelerated Mineralization Technology) was developed aiming at the treatment of ashes and production of soil-like material for reuse. The objective of the project EJA was to evaluate the AMT process on the basis of available information and the possibilities the process could offer with respect to the conditions present in Sweden. With support of researchers at NIES, available literature including unpublished manuscripts on the AMT process was compiled, translated and evaluated. During treatment, the ashes are washed, aged and mixed with up to 5 % by weight of biodegradable organic matter. The material is stabilized at landfill. During up to several decades, metals are demobilized through a combination of three mechanisms, viz. carbonation, clay formation, and humification. Also persistent organic pollutants (POP) are demobilized due to humification products or they are degraded anaerobically. When the treatment is completed, the reuse of the material is envisaged. Due to the long treatment period, the AMT method might not be favored by ash producers in Sweden. In the future, landfill companies could be interested in the technology, since they are experienced to handle waste at long sight. This, however, requires that the legislation does not pose any hindrance for the implementation of the method, e.g. regarding the requirement to add organic matter to the ash. Above all, it remains several years of research on the AMT process to fully understand and evaluate the underlying biological and chemical processes as well as their interaction.

  1. Biogeochemical Modeling of the Second Rise of Oxygen

    Science.gov (United States)

    Smith, M. L.; Catling, D.; Claire, M.; Zahnle, K.

    2014-03-01

    cycles). To determine how fluxes of sulfur, carbon, and oxygen define oxygen levels before, during, and after the NOE, we add a sulfur cycle to the biogeochemical model of Claire et al. (2006). Understanding processes that impact the evolution of atmospheric oxygen on Earth is key to diagnosing the habitability of other planets because it is possible that other planets undergo a similar evolution. If a sulfidic deep ocean was instrumental in driving oxygen levels to modern values, then it would be valuable to remotely detect a sulfide-rich ocean on another planet. One such remotely-detectable signature could be the color of a sulfide-rich ocean. For example, Gallardo and Espinoza (2008) have hypothesized that a sulfidic ocean may be have been blacker in color. Even if a sulfidic ocean is not key to oxygenation, detecting a planet in transition--that is, a planet with intermediate levels of oxygen co-existing with higher levels of reduced gases - would be important for diagnosing habitability.

  2. Methods for biogeochemical studies of sea ice: The state of the art, caveats, and recommendations

    Directory of Open Access Journals (Sweden)

    Lisa A. Miller

    2015-01-01

    Full Text Available Abstract Over the past two decades, with recognition that the ocean’s sea-ice cover is neither insensitive to climate change nor a barrier to light and matter, research in sea-ice biogeochemistry has accelerated significantly, bringing together a multi-disciplinary community from a variety of fields. This disciplinary diversity has contributed a wide range of methodological techniques and approaches to sea-ice studies, complicating comparisons of the results and the development of conceptual and numerical models to describe the important biogeochemical processes occurring in sea ice. Almost all chemical elements, compounds, and biogeochemical processes relevant to Earth system science are measured in sea ice, with published methods available for determining biomass, pigments, net community production, primary production, bacterial activity, macronutrients, numerous natural and anthropogenic organic compounds, trace elements, reactive and inert gases, sulfur species, the carbon dioxide system parameters, stable isotopes, and water-ice-atmosphere fluxes of gases, liquids, and solids. For most of these measurements, multiple sampling and processing techniques are available, but to date there has been little intercomparison or intercalibration between methods. In addition, researchers collect different types of ancillary data and document their samples differently, further confounding comparisons between studies. These problems are compounded by the heterogeneity of sea ice, in which even adjacent cores can have dramatically different biogeochemical compositions. We recommend that, in future investigations, researchers design their programs based on nested sampling patterns, collect a core suite of ancillary measurements, and employ a standard approach for sample identification and documentation. In addition, intercalibration exercises are most critically needed for measurements of biomass, primary production, nutrients, dissolved and particulate

  3. Evaluation of feeds for melt and dilute process using an Analytical Hierarchy Process

    International Nuclear Information System (INIS)

    Krupa, J.F.

    2000-01-01

    WSRC was requested to evaluate whether nuclear materials other than aluminum-clad spent nuclear fuel should be considered for treatment to prepare them for disposal in the melt and dilute facility as part of the Treatment and Storage Facility (TSF) currently projected for construction in the L-Reactor process area. The Analytical Hierarchy Process using a ratings methodology was used to rank potential feed candidates for disposition through the Melt and Dilute facility proposed for disposition of Savannah River Site aluminum-clad spent nuclear fuel. Because of the scoping nature of this analysis, the expert team convened for this purpose concentrated on technical feasibility and potential cost impacts associated with using melt and dilute versus the current disposition option

  4. Improving occupational health care for construction workers: a process evaluation.

    Science.gov (United States)

    Boschman, Julitta S; van der Molen, Henk F; Sluiter, Judith K; Frings-Dresen, Monique H W

    2013-03-11

    To evaluate the process of a job-specific workers' health surveillance (WHS) in improving occupational health care for construction workers. From January to July 2012 were 899 bricklayers and supervisors invited for the job-specific WHS at three locations of one occupational health service throughout the Netherlands. The intervention aimed at detecting signs of work-related health problems, reduced work capacity and/or reduced work functioning. Measurements were obtained using a recruitment record and questionnaires at baseline and follow-up. The process evaluation included the following: reach (attendance rate), intervention dose delivered (provision of written recommendations and follow-up appointments), intervention dose received (intention to follow-up on advice directly after WHS and remembrance of advice three months later), and fidelity (protocol adherence). The workers scored their increase in knowledge from 0-10 with regard to health status and work ability, their satisfaction with the intervention and the perceived (future) effect of such an intervention. Program implementation was defined as the mean score of reach, fidelity, and intervention dose delivered and received. Reach was 9% (77 workers participated), fidelity was 67%, the intervention dose delivered was 92 and 63%, and the intervention dose received was 68 and 49%. The total programme implementation was 58%. The increases in knowledge regarding the health status and work ability of the workers after the WHS were graded as 7.0 and 5.9, respectively. The satisfaction of the workers with the entire intervention was graded as 7.5. The perceived (future) effects on health status were graded as 6.3, and the effects on work ability were graded with a 5.2. The economic recession affected the workers as well as the occupational health service that enacted the implementation. Programme implementation was acceptable. Low reach, limited protocol adherence and modest engagement of the workers with respect

  5. A model evaluation checklist for process-based environmental models

    Science.gov (United States)

    Jackson-Blake, Leah

    2015-04-01

    Mechanistic catchment-scale phosphorus models appear to perform poorly where diffuse sources dominate. The reasons for this were investigated for one commonly-applied model, the INtegrated model of CAtchment Phosphorus (INCA-P). Model output was compared to 18 months of daily water quality monitoring data in a small agricultural catchment in Scotland, and model structure, key model processes and internal model responses were examined. Although the model broadly reproduced dissolved phosphorus dynamics, it struggled with particulates. The reasons for poor performance were explored, together with ways in which improvements could be made. The process of critiquing and assessing model performance was then generalised to provide a broadly-applicable model evaluation checklist, incorporating: (1) Calibration challenges, relating to difficulties in thoroughly searching a high-dimensional parameter space and in selecting appropriate means of evaluating model performance. In this study, for example, model simplification was identified as a necessary improvement to reduce the number of parameters requiring calibration, whilst the traditionally-used Nash Sutcliffe model performance statistic was not able to discriminate between realistic and unrealistic model simulations, and alternative statistics were needed. (2) Data limitations, relating to a lack of (or uncertainty in) input data, data to constrain model parameters, data for model calibration and testing, and data to test internal model processes. In this study, model reliability could be improved by addressing all four kinds of data limitation. For example, there was insufficient surface water monitoring data for model testing against an independent dataset to that used in calibration, whilst additional monitoring of groundwater and effluent phosphorus inputs would help distinguish between alternative plausible model parameterisations. (3) Model structural inadequacies, whereby model structure may inadequately represent

  6. Past and present of sediment and carbon biogeochemical cycling models

    Directory of Open Access Journals (Sweden)

    F. T. Mackenzie

    2004-01-01

    Full Text Available The global carbon cycle is part of the much more extensive sedimentary cycle that involves large masses of carbon in the Earth's inner and outer spheres. Studies of the carbon cycle generally followed a progression in knowledge of the natural biological, then chemical, and finally geological processes involved, culminating in a more or less integrated picture of the biogeochemical carbon cycle by the 1920s. However, knowledge of the ocean's carbon cycle behavior has only within the last few decades progressed to a stage where meaningful discussion of carbon processes on an annual to millennial time scale can take place. In geologically older and pre-industrial time, the ocean was generally a net source of CO2 emissions to the atmosphere owing to the mineralization of land-derived organic matter in addition to that produced in situ and to the process of CaCO3 precipitation. Due to rising atmospheric CO2 concentrations because of fossil fuel combustion and land use changes, the direction of the air-sea CO2 flux has reversed, leading to the ocean as a whole being a net sink of anthropogenic CO2. The present thickness of the surface ocean layer, where part of the anthropogenic CO2 emissions are stored, is estimated as of the order of a few hundred meters. The oceanic coastal zone net air-sea CO2 exchange flux has also probably changed during industrial time. Model projections indicate that in pre-industrial times, the coastal zone may have been net heterotrophic, releasing CO2 to the atmosphere from the imbalance between gross photosynthesis and total respiration. This, coupled with extensive CaCO3 precipitation in coastal zone environments, led to a net flux of CO2 out of the system. During industrial time the coastal zone ocean has tended to reverse its trophic status toward a non-steady state situation of net autotrophy, resulting in net uptake of anthropogenic CO2 and storage of carbon in the coastal ocean, despite the significant calcification

  7. Biogeochemical aspects of uranium mineralization, mining, milling, and remediation

    Science.gov (United States)

    Campbell, Kate M.; Gallegos, Tanya J.; Landa, Edward R.

    2015-01-01

    Natural uranium (U) occurs as a mixture of three radioactive isotopes: 238U, 235U, and 234U. Only 235U is fissionable and makes up about 0.7% of natural U, while 238U is overwhelmingly the most abundant at greater than 99% of the total mass of U. Prior to the 1940s, U was predominantly used as a coloring agent, and U-bearing ores were mined mainly for their radium (Ra) and/or vanadium (V) content; the bulk of the U was discarded with the tailings (Finch et al., 1972). Once nuclear fission was discovered, the economic importance of U increased greatly. The mining and milling of U-bearing ores is the first step in the nuclear fuel cycle, and the contact of residual waste with natural water is a potential source of contamination of U and associated elements to the environment. Uranium is mined by three basic methods: surface (open pit), underground, and solution mining (in situ leaching or in situ recovery), depending on the deposit grade, size, location, geology and economic considerations (Abdelouas, 2006). Solid wastes at U mill tailings (UMT) sites can include both standard tailings (i.e., leached ore rock residues) and solids generated on site by waste treatment processes. The latter can include sludge or “mud” from neutralization of acidic mine/mill effluents, containing Fe and a range of coprecipitated constituents, or barium sulfate precipitates that selectively remove Ra (e.g., Carvalho et al., 2007). In this chapter, we review the hydrometallurgical processes by which U is extracted from ore, the biogeochemical processes that can affect the fate and transport of U and associated elements in the environment, and possible remediation strategies for site closure and aquifer restoration.This paper represents the fourth in a series of review papers from the U.S. Geological Survey (USGS) on geochemical aspects of UMT management that span more than three decades. The first paper (Landa, 1980) in this series is a primer on the nature of tailings and radionuclide

  8. Food chains and biogeochemical pathways: contributions of fallout and other radiotracers

    International Nuclear Information System (INIS)

    Ward Whicker, F.; Pinder, John E.

    2002-01-01

    This paper reviews examples of how measurements of global fallout in the environment and related tracer radionuclides have been used to enhance our basic knowledge of biogeochemical processes and food-chain pathways. Because it is these fundamental, natural processes that control the transport and accumulation of such trace substances in the environment, direct measurements of trace substances over time and space reveal strong insights into these processes. The necessity to monitor global fallout transport, although largely motivated by human health concerns, gave rise to a plethora of new information about plants, animals, and natural and agricultural ecosystems and how they function. This review provides a small selection of examples in the areas of plant and animal physiology, productivity and energy transfer in food chains, biogeochemical cycles of certain elements and their analogues, feeding relationships and movements of organisms, and the agriculture-based human food chain. It is concluded that if society is to cope successfully with continued growth of the human population and resource consumption, more knowledge is still required about these fundamental processes. The use of radiotracers can contribute greatly to this need, but current funding priorities, societal attitudes, and onerous regulations on the use of radioactivity may continue to limit such applications. (author)

  9. Evaluation of processed borax as antidote for aconite poisoning.

    Science.gov (United States)

    Sarkar, Prasanta Kumar; Prajapati, Pradeep K; Shukla, Vinay J; Ravishankar, Basavaiah

    2017-06-09

    Aconite root is very poisonous; causes cardiac arrhythmias, ventricular fibrillation and ventricular tachycardia. There is no specific antidote for aconite poisoning. In Ayurveda, dehydrated borax is mentioned for management of aconite poisoning. The investigation evaluated antidotal effect of processed borax against acute and sub-acute toxicity, cardiac toxicity and neuro-muscular toxicity caused by raw aconite. For acute protection Study, single dose of toxicant (35mg/kg) and test drug (22.5mg/kg and 112.5mg/kg) was administered orally, and then 24h survival of animals was observed. The schedule was continued for 30 days in sub-acute protection Study with daily doses of toxicant (6.25mg/kg), test drug (22.5mg/kg and 112.5mg/kg) and vehicle. Hematological and biochemical tests of blood and serum, histopathology of vital organs were carried out. The cardiac activity Study was continued for 30 days with daily doses of toxicant (6.25mg/kg), test drug (22.5mg/kg), processed borax solution (22.5mg/kg) and vehicle; ECG was taken after 1h of drug administration on 1 TB , 15th and on 30th day. For neuro-muscular activity Study, the leech dorsal muscle response to 2.5µg of acetylcholine followed by response of toxicant at 25µg and 50µg doses and then response of test drug at 25µg dose were recorded. Protection index indicates that treated borax gave protection to 50% rats exposed to the lethal dose of toxicant in acute protection Study. Most of the changes in hematological, biochemical parameters and histopathological Study induced by the toxicant in sub-acute protection Study were reversed significantly by the test drug treatment. The ventricular premature beat and ventricular tachyarrhythmia caused by the toxicant were reversed by the test drug indicate reversal of toxicant induced cardio-toxicity. The acetylcholine induced contractions in leech muscle were inhibited by toxicant and it was reversed by test drug treatment. The processed borax solution is found as an

  10. Field evaluations of a forestry version of DRAINMOD-NII model

    Science.gov (United States)

    S. Tian; M. A. Youssef; R.W. Skaggs; D.M. Amatya; G.M. Chescheir

    2010-01-01

    This study evaluated the performance of the newly developed forestry version of DRAINMOD-NII model using a long term (21-year) data set collected from an artificially drained loblolly pine (Pinus taeda L.) plantation in eastern North Carolina, U.S.A. The model simulates the main hydrological and biogeochemical processes in drained forested lands. The...

  11. Towards an Evaluation Framework for Business Process Integration and Management

    NARCIS (Netherlands)

    Mutschler, B.B.; Reichert, M.U.; Bumiller, J.

    2005-01-01

    Process-awareness in enterprise computing is a must in order to adequately support business processes. Particularly the interoperability of the (process-oriented) business information systems and the management of a company’s process map are difficult to handle. Process-oriented approaches (like

  12. EVALUATION OF CORROSION COST OF CRUDE OIL PROCESSING INDUSTRY

    Directory of Open Access Journals (Sweden)

    ADESANYA A.O.

    2012-08-01

    Full Text Available Crude oil production industry as the hub of Nigeria Economy is not immune to the global financial meltdown being experienced world over which have resulted in a continual fall of oil price. This has necessitated the need to reduce cost of production. One of the major costs of production is corrosion cost, hence, its evaluation. This research work outlined the basic principles of corrosion prevention, monitoring and inspection and attempted to describe ways in which these measures may be adopted in the context of oil production. A wide range of facilities are used in crude oil production making it difficult to evaluate precisely the extent of corrosion and its cost implication. In this study, cost of corrosion per barrel was determined and the annualized value of corrosion cost was also determined using the principles of engineering economy and results analyzed using descriptive statistics. The results showed that among the corrosion prevention methods identified, the use of chemical treatment gave the highest cost contribution (81% of the total cost of prevention while coating added 19%. Cleaning pigging and cathodic protection gave no cost. The contribution of corrosion maintenance methods are 60% for repairs and 40% for replacement. Also among the corrosion monitoring and inspection identified, NDT gave the highest cost contribution of 41% of the total cost, followed by coating survey (34%. Cathodic protection survey and crude analysis gives the lowest cost contribution of 19% and 6% respectively. Corrosion control cost per barrel was found to be 77 cent/barrel. The significance of this cost was not much due to high price of crude oil in the international market. But the effect of corrosion in crude oil processing takes its toll on crude oil production (i.e. deferment.

  13. Fast evaluation of Helmholtz potential on graphics processing units (GPUs)

    Science.gov (United States)

    Li, Shaojing; Livshitz, Boris; Lomakin, Vitaliy

    2010-11-01

    This paper presents a parallel algorithm implemented on graphics processing units (GPUs) for rapidly evaluating spatial convolutions between the Helmholtz potential and a large-scale source distribution. The algorithm implements a non-uniform grid interpolation method (NGIM), which uses amplitude and phase compensation and spatial interpolation from a sparse grid to compute the field outside a source domain. NGIM reduces the computational time cost of the direct field evaluation at N observers due to N co-located sources from O( N2) to O( N) in the static and low-frequency regimes, to O( N log N) in the high-frequency regime, and between these costs in the mixed-frequency regime. Memory requirements scale as O( N) in all frequency regimes. Several important differences between CPU and GPU implementations of the NGIM are required to result in optimal performance on respective platforms. In particular, in the CPU implementations all operations, where possible, are pre-computed and stored in memory in a preprocessing stage. This reduces the computational time but significantly increases the memory consumption. In the GPU implementations, where handling memory often is a critical bottle neck, several special memory handling techniques are used to accelerate the computations. A significant latency of the GPU global memory access is hidden by implementing coalesced reading, which requires arranging many array elements in contiguous parts of memory. Contrary to the CPU version, most of the steps in the GPU implementations are executed on-fly and only necessary arrays are kept in memory. This results in significantly reduced memory consumption, increased problem size N that can be handled, and reduced computational time on GPUs. The obtained GPU-CPU speed-up ratios are from 150 to 400 depending on the required accuracy and problem size. The presented method and its CPU and GPU implementations can find important applications in various fields of physics and engineering.

  14. Process optimization and evaluation of novel baicalin solid nanocrystals

    Directory of Open Access Journals (Sweden)

    Yue PF

    2013-08-01

    Full Text Available Peng-Fei Yue,1,2 Yu Li,1 Jing Wan,1 Yong Wang,1 Ming Yang,1 Wei-Feng Zhu,1 Chang-Hong Wang,2 Hai-Long Yuan31Key Lab of Modern Preparation of TCM, Jiangxi University of Traditional Chinese Medicine, Nanchang, 2Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai, 3302 Hospital of PLA Institute of Chinese Materia Medica, Beijing, People's Republic of ChinaAbstract: The objective of this study was to prepare baicalin solid nanocrystals (BCN-SNS to enhance oral bioavailability of baicalin. A Box–Behnken design approach was used for process optimization. The physicochemical properties and pharmacokinetics of the optimal BCN-SNS were investigated. Multiple linear regression analysis for process optimization revealed that the fine BCN-SNS was obtained wherein the optimal values of homogenization pressure (bar, homogenization cycles (cycles, amount of TPGS to drug (w/w, and amount of MCCS to drug (w/w were 850 bar, 25 cycles, 10%, and 10%, respectively. Transmission electron microscopy and scanning electron microscopy results indicated that no significant aggregation or crystal growth could be observed in the redispersed freeze-dried BCN-SNS. Differential scanning calorimetry and X-ray diffraction results showed that BCN remained in a crystalline state. Dissolution velocity of the freeze-dried BCN-SNS powder was distinctly superior compared to those of the crude powder and physical mixture. The bioavailability of BCN in rats was increased remarkably after oral administration of BCN-SNS (P < 0.05, compared with those of BCN or the physical mixture. The SNS might be a good choice for oral administration of poorly soluble BCN, due to an improvement of the bioavailability and dissolution velocity of BCN-SNS.Keywords: baicalin, solid nanocrystals, optimization, in vivo/vitro evaluation

  15. The impacts of climate change and human activities on biogeochemical cycles on the Qinghai-Tibetan Plateau.

    Science.gov (United States)

    Chen, Huai; Zhu, Qiuan; Peng, Changhui; Wu, Ning; Wang, Yanfen; Fang, Xiuqing; Gao, Yongheng; Zhu, Dan; Yang, Gang; Tian, Jianqing; Kang, Xiaoming; Piao, Shilong; Ouyang, Hua; Xiang, Wenhua; Luo, Zhibin; Jiang, Hong; Song, Xingzhang; Zhang, Yao; Yu, Guirui; Zhao, Xinquan; Gong, Peng; Yao, Tandong; Wu, Jianghua

    2013-10-01

    With a pace of about twice the observed rate of global warming, the temperature on the Qinghai-Tibetan Plateau (Earth's 'third pole') has increased by 0.2 °C per decade over the past 50 years, which results in significant permafrost thawing and glacier retreat. Our review suggested that warming enhanced net primary production and soil respiration, decreased methane (CH(4)) emissions from wetlands and increased CH(4) consumption of meadows, but might increase CH(4) emissions from lakes. Warming-induced permafrost thawing and glaciers melting would also result in substantial emission of old carbon dioxide (CO(2)) and CH(4). Nitrous oxide (N(2)O) emission was not stimulated by warming itself, but might be slightly enhanced by wetting. However, there are many uncertainties in such biogeochemical cycles under climate change. Human activities (e.g. grazing, land cover changes) further modified the biogeochemical cycles and amplified such uncertainties on the plateau. If the projected warming and wetting continues, the future biogeochemical cycles will be more complicated. So facing research in this field is an ongoing challenge of integrating field observations with process-based ecosystem models to predict the impacts of future climate change and human activities at various temporal and spatial scales. To reduce the uncertainties and to improve the precision of the predictions of the impacts of climate change and human activities on biogeochemical cycles, efforts should focus on conducting more field observation studies, integrating data within improved models, and developing new knowledge about coupling among carbon, nitrogen, and phosphorus biogeochemical cycles as well as about the role of microbes in these cycles. © 2013 John Wiley & Sons Ltd.

  16. Evaluation And Selection Process of Suppliers Through Analytical Framework: An Emprical Evidence of Evaluation Tool

    Directory of Open Access Journals (Sweden)

    Imeri Shpend

    2015-09-01

    Full Text Available The supplier selection process is very important to companies as selecting the right suppliers that fit companies strategy needs brings drastic savings. Therefore, this paper seeks to address the key area of supplies evaluation from the supplier review perspective. The purpose was to identify the most important criteria for suppliers’ evaluation and develop evaluation tool based on surveyed criteria. The research was conducted through structured questionnaire and the sample focused on small to medium sized companies (SMEs in Greece. In total eighty companies participated in the survey answering the full questionnaire which consisted of questions whether these companies utilize some suppliers’ evaluation criteria and what criteria if any is applied. The main statistical instrument used in the study is Principal Component Analysis (PCA. Thus, the research has shown that the main criteria are: the attitude of the vendor towards the customer, supplier delivery time, product quality and price. Conclusions are made on the suitability and usefulness of suppliers’ evaluation criteria and in way they are applied in enterprises.

  17. Nanostructural and biogeochemical features of the crinoid stereom

    Science.gov (United States)

    Gorzelak, P.; Stolarski, J.; Mazur, M.; Marrocchi, Y.; Meibom, A.; Chalmin, E.

    2009-04-01

    Representatives of all echinoderm clades (e.g., echinoids, holothuroids, ophiuroids, asteroids, and crinoids) form elaborate calcitic (polymorph of calcium carbonate) skeletons composed of numerous plates. Each plate consists of a three-dimensional meshwork of mineral trabeculae (stereom) that results from precisely orchestrated biomineralization processes. Individual skeletal plates behave as single calcite crystals as shown by X-ray diffraction and polarizing microscopy, however, their physico-chemical properties differ significantly from the properties of geologic or synthetic calcites. For example, echinoderm bio-calcite does not show cleavage planes typical of calcite but reveals conchoidal fracture surfaces that reduce the brittleness of the material. The unique properties of echinoderm bio-calcite result from intimate involvement of organic molecules in the biomineralization process and their incorporation into the crystal structure. Remnants of echinoderm skeleton are among the most frequently found fossils in the Mesozoic and Palaeozoic rocks thus, in order to use them as environmental proxies, it is necessary to understand the degree of biological ("vital effect") and inorganic control over their formation. Here, we show first nanoscale structural and biogeochemical properties of the stereom of extant and fossil crinoids. Using FESEM and AFM imaging techniques we show that the skeleton has nanocomposite structure: individual grains have ca. 100 nm in diameter and occasionally form larger aggregates. Fine scale geobiochemical mappings of crinoid plates (NanoSIMS microprobe) show that Mg is distributed heterogeneously in the stereom with higher concentration in the middle part of the trabecular bars. Although organic components constitute only ca. 0.10-0.26 wt% of modern echinoderm bio-calcite, in situ synchrotron sulphur K-edge x-ray absorption near edge structure (XANES) spectra show that the central parts of stereom bars contain higher levels of SO4 that

  18. The Biogeochemical Response to Inter-decadal Atmospheric Forcing Across Watershed Scales in Canada's Subarctic

    Science.gov (United States)

    Spence, C.

    2016-12-01

    Rapid landscape changes in the circumpolar north have been documented, including degradation of permafrost and alteration of vegetation communities. These are widely expected to have profound impacts on the freshwater fluxes of solutes, carbon and nitrogen across the Arctic domain. However, there have been few attempts to document trends across the diversity of landscapes in the circumpolar north, mostly due to a dearth of long term data. Some of the fastest rates of warming over the last thirty years have occurred in Canada's Northwest Territories, so this region should already exhibit changes in aquatic chemistry. Observations of chemical loads in streams draining the ice-poor discontinuous permafrost subarctic Canadian Shield region were analyzed with the goal of determining how basins across scales have responded to changes in atmospheric forcing. Smaller streams, with much closer linkages to terrestrial processes, experienced a synchrony among hydrological and biogeochemical processes that enhanced chemical flux above that in their larger counterparts. This demonstrates that there are differences in resiliency and resistance across scales to climate change. These results highlight the importance of biogeochemical process understanding to properly explain and predict how chemical loading scales from headwaters to river mouths. This is important information if society is to properly adapt policies for effluent discharge, nearshore marine management, among others.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  20. HOME COMPOSTING: IMPLEMENTATION AND EVALUATION OF THE PROCESS

    Directory of Open Access Journals (Sweden)

    Lucas Lourenço Castiglioni Guidoni

    2013-07-01

    Full Text Available : In Brazil, the Municipal Solid Waste (RSU, from Portuguese Resíduo Sólido Urbano is a growing issue that is faced both in the formal field, in regulatory laws, as well as in management practices, concerning social and environmental responsibility of individuals, businesses and municipalities. Among the several components, organic matter corresponds to more than half of the entire amount of generated waste. As a treatment and a recycling alternative, home composting can improve the use of this fraction generated by Brazilian households. Therefore, the aim of this paper is to implement and evaluate a home composting system in four households. In each residence it was set up a cylindrical reactor of 255L to store the leftovers of fruit and vegetables as it was generated, being mixed and covered with rice hull. Weekly, the temperature and volume of the filled reactors were recorded. The final composts were assessed by the macro and micronutrients contained and their maturity stage. As a result, it was possible to reduce the amount of waste allocated for public management by the recycling source. The efficiency of the process was verified by monitoring the temperature and the absence of unpleasant odors. When 90 days were elapsed after the attendance, three of the researched households have remained with the composting system, voluntarily.

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

    International Nuclear Information System (INIS)

    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

  2. Phosphorus Accumulating Organisms and Biogeochemical Hotspots

    Science.gov (United States)

    Archibald, J.; Walter, M. T.

    2008-12-01

    Despite extensive research, many of the processes that control phosphorus (P) movement from agricultural fields to streams and lakes are not well understood. This limits our ability to develop management strategies that will mediate P contamination of freshwater ecosystems and subsequent eutrophication. Recent advances in molecular microbiology have prompted a paradigm shift in wastewater treatment that recognizes and exploits the ways specific microbial processes influence P solubility. Central to this enhanced biological phosphorus removal in wastewater treatment plants is a relatively recently discovered microorganism, Candidatus accumulibacter, which takes-up P and stores it internally as polyphosphate under alternating aerobic and anaerobic conditions. Within the past few months we have discovered this organism in the natural environment and its role in P biogeochemistry is unclear. We speculate that it may function similarly in variable source areas, which experience cycles of saturation and desaturation, as it does in the anaerobic- aerobic cycles in a wastewater treatment plant. If so, there may be potential opportunities to realize similarly new perspectives and advancements in the watershed context as have been seen in wastewater technologies. Here we present some of our preliminary findings.

  3. Lagrangian numerical methods for ocean biogeochemical simulations

    Science.gov (United States)

    Paparella, Francesco; Popolizio, Marina

    2018-05-01

    We propose two closely-related Lagrangian numerical methods for the simulation of physical processes involving advection, reaction and diffusion. The methods are intended to be used in settings where the flow is nearly incompressible and the Péclet numbers are so high that resolving all the scales of motion is unfeasible. This is commonplace in ocean flows. Our methods consist in augmenting the method of characteristics, which is suitable for advection-reaction problems, with couplings among nearby particles, producing fluxes that mimic diffusion, or unresolved small-scale transport. The methods conserve mass, obey the maximum principle, and allow to tune the strength of the diffusive terms down to zero, while avoiding unwanted numerical dissipation effects.

  4. Ocean fronts drive marine fishery production and biogeochemical cycling.

    Science.gov (United States)

    Woodson, C Brock; Litvin, Steven Y

    2015-02-10

    Long-term changes in nutrient supply and primary production reportedly foreshadow substantial declines in global marine fishery production. These declines combined with current overfishing, habitat degradation, and pollution paint a grim picture for the future of marine fisheries and ecosystems. However, current models forecasting such declines do not account for the effects of ocean fronts as biogeochemical hotspots. Here we apply a fundamental technique from fluid dynamics to an ecosystem model to show how fronts increase total ecosystem biomass, explain fishery production, cause regime shifts, and contribute significantly to global biogeochemical budgets by channeling nutrients through alternate trophic pathways. We then illustrate how ocean fronts affect fishery abundance and yield, using long-term records of anchovy-sardine regimes and salmon abundances in the California Current. These results elucidate the fundamental importance of biophysical coupling as a driver of bottom-up vs. top-down regulation and high productivity in marine ecosystems.

  5. Retrospective (in-process) project evaluation system. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1978-12-20

    The retrospective evaluation methodology is being developed to monitor progress in energy conservation projects and to evaluate their success at completion. The criteria for evaluation will vary according to the project, the anticipated role that the federal government expects to play in development and commercialization, and the level of technology development. Evaluation guidelines are presented and their application is illustrated using a residential water heater refit kit; energy conservation in restaurants; and a national infrared thermography program. (MCW)

  6. Evaluation of economic efficiency of process improvement in food packaging

    Directory of Open Access Journals (Sweden)

    Jana Hron

    2012-01-01

    Full Text Available In general, we make gains in process by the three fundamental ways. First, we define or redefine our process in a strategic sense. Second, once defined or redefined, we commence process operations and use process control methods to target and stabilize our process. Third, we use process improvement methods, as described in this paper, along with process control to fully exploit our process management and/or technology. Process improvement is focused primarily in our subprocesses and sub-subprocesses. Process leverage is the key to process improvement initiatives. This means that small improvements of the basic manufacturing operations can have (with the assumption of mass repetition of the operation a big impact on the functioning of the whole production unit. The complexity within even small organizations, in people, products, and processes, creates significant challenges in effectively and efficiently using these initiatives tools. In this paper we are going to place process purposes in the foreground and initiatives and tools in the background as facilitator to help accomplish process purpose. Initiatives and tools are not the ends we are seeking; result/outcomes in physical, economics, timeliness, and customer service performance matter. In the paper process boundaries (in a generic sense are set by our process purpose and our process definition. Process improvement is initiated within our existing process boundaries. For example, in a fast-food restaurant, if we define our cooking process around a frying technology, then we provide process improvements within our frying technology. On the other hand, if we are considering changing to a broiling technology, then we are likely faced with extensive change, impacting our external customers, and a process redefinition may be required. The result / aim of the paper are based on the example of the process improving of a food packaging quality. Specifically, the integration of two approaches

  7. Developing biogeochemical tracers of apatite weathering by ectomycorrhizal fungi

    Science.gov (United States)

    Vadeboncoeur, M. A.; Bryce, J. G.; Hobbie, E. A.; Meana-Prado, M. F.; Blichert-Toft, J.

    2012-12-01

    Chronic acid deposition has depleted calcium (Ca) from many New England forest soils, and intensive harvesting may reduce phosphorus (P) available to future rotations. Thin glacial till soils contain trace amounts of apatite, a primary calcium phosphate mineral, which may be an important long-term source of both P and Ca to ecosystems. The extent to which ECM fungi enhance the weathering rate of primary minerals in soil which contain growth-limiting nutrients remains poorly quantified, in part due to biogeochemical tracers which are subsequently masked by within-plant fractionation. Rare earth elements (REEs) and Pb isotope ratios show some potential for revealing differences in soil apatite weathering rates across forest stands and silvicultural treatments. To test the utility of these tracers, we grew birch seedlings semi-hydroponically under controlled P-limited conditions, supplemented with mesh bags containing granite chips. Our experimental design included nonmycorrhizal (NM) as well as ectomycorrhizal cultures (Cortinarius or Leccinum). Resulting mycorrhizal roots and leachates of granite chips were analyzed for these tracers. REE concentrations in roots were greatly elevated in treatments with granite relative to those without granite, demonstrating uptake of apatite weathering products. Roots with different mycorrhizal fungi accumulated similar concentrations of REEs and were generally elevated compared to the NM cultures. Ammonium chloride leaches of granite chips grown in contact with mycorrhizal hyphae show elevated REE concentrations and significantly radiogenic Pb isotope signatures relative to bulk rock, also supporting enhanced apatite dissolution. Our results in culture are consistent with data from field-collected sporocarps from hardwood stands in the Bartlett Experimental Forest in New Hampshire, in which Cortinarius sporocarp Pb isotope ratios were more radiogenic than those of other ectomycorrhizal sporocarps. Taken together, the experimental

  8. Earth's Early Biosphere and the Biogeochemical Carbon Cycle

    Science.gov (United States)

    DesMarais, David

    2004-01-01

    Our biosphere has altered the global environment principally by influencing the chemistry of those elements most important for life, e g., C, N, S, O, P and transition metals (e.g., Fe and Mn). The coupling of oxygenic photosynthesis with the burial in sediments of photosynthetic organic matter, and with the escape of H2 to space, has increased the state of oxidation of the Oceans and atmosphere. It has also created highly reduced conditions within sedimentary rocks that have also extensively affected the geochemistry of several elements. The decline of volcanism during Earth's history reduced the flow of reduced chemical species that reacted with photosynthetically produced O2. The long-term net accumulation of photosynthetic O2 via biogeochemical processes has profoundly influenced our atmosphere and biosphere, as evidenced by the O2 levels required for algae, multicellular life and certain modem aerobic bacteria to exist. When our biosphere developed photosynthesis, it tapped into an energy resource that was much larger than the energy available from oxidation-reduction reactions associated with weathering and hydrothermal activity. Today, hydrothermal sources deliver globally (0.13-1.1)x10(exp l2) mol yr(sup -1) of reduced S, Fe(2+), Mn(2+), H2 and CH4; this is estimated to sustain at most about (0.2-2)xl0(exp 12)mol C yr(sup -1) of organic carbon production by chemautotrophic microorganisms. In contrast, global photosynthetic productivity is estimated to be 9000x10(exp 12) mol C yr(sup -1). Thus, even though global thermal fluxes were greater in the distant geologic past than today, the onset of oxygenic photosynthesis probably increased global organic productivity by some two or more orders of magnitude. This enormous productivity materialized principally because oxygenic photosynthesizers unleashed a virtually unlimited supply of reduced H that forever freed life from its sole dependence upon abiotic sources of reducing power such as hydrothermal emanations

  9. Processing and evaluation of image matching tools in radiotherapy

    International Nuclear Information System (INIS)

    Bondiau, P.Y.

    2004-11-01

    Cancer is a major problem of public health. Treatment can be done in a general or loco-regional way, in this last case medical images are important as they specify the localization of the tumour. The objective of the radiotherapy is to deliver a curative dose of radiation in the target volume while sparing the organs at risks (O.A.R.). The determination of the accurate localization of the targets volume as well as O.A.R. make it possible to define the ballistic of irradiation beams. After the description of the principles of radiotherapy and cancers treatment, we specify the clinical stakes of ocular, cerebral and prostatic tumours. We present a state of the art of image matching, the various techniques reviewed with an aim of being didactic with respect to the medical community. The results of matching are presented within the framework of the planning of the cerebral and prostatic radiotherapy in order to specify the types of applicable matching in oncology and more particularly in radiotherapy. Then, we present the prospects for this type of application according to various anatomical areas. Applications of automatic segmentation and the evaluation of the results in the framework of brain tumour are described after a review of the various segmentation methods according to anatomical localizations. We will see an original application: the digital simulation of the virtual tumoral growth and the comparison with the real growth of a cerebral tumour presented by a patient. Lastly, we will expose the future developments possible of the tools for image processing in radiotherapy as well as the tracks of research to be explored in oncology. (author)

  10. New Management Whole Process Evaluation of DSM Projects Based on Fuzzy-AHP Approach

    OpenAIRE

    Xiaoli Zhu; Mingjuan Ma; Song Xue; Dinglin Li; Ming Zeng

    2013-01-01

    In order to promote the development of DSM projects, it is necessary to establish a management evaluation indicator system considering whole process. This study analyzes key factors of every stage of DSM projects combining with the whole process theory and proposes a new evaluation indicator system of DSM projects management. Also we use fuzzy analytic hierarchy process which combines analytic hierarchy process and fuzzy comprehensive evaluation method to evaluate DSM projects management cons...

  11. Radiation Evaluation and Concept Development for Analog Probability Processing Technology

    Data.gov (United States)

    National Aeronautics and Space Administration — Analog probability processing technology has the ability to provide game-changing performance advances and power savings for on-board data processing applications....

  12. Evaluation of breast cancer through mammographies and image digital processing

    International Nuclear Information System (INIS)

    Crestana, Rita H.S.

    1995-01-01

    The state of art of image processing has provided important advances to many scientific investigation areas particularly to medical own. This work exploits the potentiality of using image processing techniques for analyzing breast phantoms and mammographies. 36 refs., 62 figs

  13. Study on process evaluation model of students' learning in practical course

    Science.gov (United States)

    Huang, Jie; Liang, Pei; Shen, Wei-min; Ye, Youxiang

    2017-08-01

    In practical course teaching based on project object method, the traditional evaluation methods include class attendance, assignments and exams fails to give incentives to undergraduate students to learn innovatively and autonomously. In this paper, the element such as creative innovation, teamwork, document and reporting were put into process evaluation methods, and a process evaluation model was set up. Educational practice shows that the evaluation model makes process evaluation of students' learning more comprehensive, accurate, and fairly.

  14. Improving National Capability in Biogeochemical Flux Modelling: the UK Environmental Virtual Observatory (EVOp)

    Science.gov (United States)

    Johnes, P.; Greene, S.; Freer, J. E.; Bloomfield, J.; Macleod, K.; Reaney, S. M.; Odoni, N. A.

    2012-12-01

    The best outcomes from watershed management arise where policy and mitigation efforts are underpinned by strong science evidence, but there are major resourcing problems associated with the scale of monitoring needed to effectively characterise the sources rates and impacts of nutrient enrichment nationally. The challenge is to increase national capability in predictive modelling of nutrient flux to waters, securing an effective mechanism for transferring knowledge and management tools from data-rich to data-poor regions. The inadequacy of existing tools and approaches to address these challenges provided the motivation for the Environmental Virtual Observatory programme (EVOp), an innovation from the UK Natural Environment Research Council (NERC). EVOp is exploring the use of a cloud-based infrastructure in catchment science, developing an exemplar to explore N and P fluxes to inland and coastal waters in the UK from grid to catchment and national scale. EVOp is bringing together for the first time national data sets, models and uncertainty analysis into cloud computing environments to explore and benchmark current predictive capability for national scale biogeochemical modelling. The objective is to develop national biogeochemical modelling capability, capitalising on extensive national investment in the development of science understanding and modelling tools to support integrated catchment management, and supporting knowledge transfer from data rich to data poor regions, The AERC export coefficient model (Johnes et al., 2007) has been adapted to function within the EVOp cloud environment, and on a geoclimatic basis, using a range of high resolution, geo-referenced digital datasets as an initial demonstration of the enhanced national capacity for N and P flux modelling using cloud computing infrastructure. Geoclimatic regions are landscape units displaying homogenous or quasi-homogenous functional behaviour in terms of process controls on N and P cycling

  15. Climate Leadership Awards Application Process, Eligibility, and Evaluation Criteria

    Science.gov (United States)

    Learn about evaluation criteria and access applications for the 2018 Climate Leadership Awards, which publicly recognizes individuals and organizations for their outstanding leadership in reducing greenhouse gas emissions.

  16. Process evaluation of a workplace health promotion intervention aimed at improving work engagement and energy balance

    NARCIS (Netherlands)

    Berkel, J. van; Boot, C.R.L.; Proper, K.I.; Bongers, P.M.; Beek, A.J. van der

    2013-01-01

    OBJECTIVE:: To evaluate the process of the implementation of an intervention aimed at improving work engagement and energy balance, and to explore associations between process measures and compliance. METHODS:: Process measures were assessed using a combination of quantitative and qualitative

  17. Process Evaluation of a Workplace Health Promotion Intervention Aimed at Improving Work Engagement and Energy Balance

    NARCIS (Netherlands)

    van Berkel, J.; Boot, C.R.L.; Proper, K.I.; Bongers, P.M.; van der Beek, A.J.

    2013-01-01

    OBJECTIVE:: To evaluate the process of the implementation of an intervention aimed at improving work engagement and energy balance, and to explore associations between process measures and compliance. METHODS:: Process measures were assessed using a combination of quantitative and qualitative

  18. Process evaluation of the Bristol girls dance project.

    Science.gov (United States)

    Sebire, S J; Edwards, M J; Kesten, J M; May, T; Banfield, K J; Bird, E L; Tomkinson, K; Blair, P; Powell, J E; Jago, R

    2016-04-21

    The Bristol Girls Dance Project was a cluster randomised controlled trial that aimed to increase objectively measured moderate-to-vigorous physical activity (MVPA) levels of Year 7 (age 11-12) girls through a dance-based after-school intervention. The intervention was delivered in nine schools and consisted of up to forty after-school dance sessions. This paper reports on the main findings from the detailed process evaluation that was conducted. Quantitative and qualitative data were collected from intervention schools. Dose and fidelity were reported by dance instructors at every session. Intervention dose was defined as attending two thirds of sessions and was measured by attendance registers. Fidelity to the intervention manual was reported by dance instructors. On four randomly-selected occasions, participants reported their perceived level of exertion and enjoyment. Reasons for non-attendance were self-reported at the end of the intervention. Semi-structured interviews were conducted with all dance instructors who delivered the intervention (n = 10) and school contacts (n = 9) in intervention schools. A focus group was conducted with girls who participated in each intervention school (n = 9). The study did not affect girls' MVPA. An average of 31.7 girls participated in each school, with 9.1 per school receiving the intervention dose. Mean attendance and instructors' fidelity to the intervention manual decreased over time. The decline in attendance was largely attributed to extraneous factors common to after-school activities. Qualitative data suggest that the training and intervention manual were helpful to most instructors. Participant ratings of session enjoyment were high but perceived exertion was low, however, girls found parts of the intervention challenging. The intervention was enjoyed by participants. Attendance at the intervention sessions was low but typical of after-school activities. Participants reported that the intervention brought

  19. Process evaluation of the Bristol girls dance project

    Directory of Open Access Journals (Sweden)

    S. J. Sebire

    2016-04-01

    Full Text Available Abstract Background The Bristol Girls Dance Project was a cluster randomised controlled trial that aimed to increase objectively measured moderate-to-vigorous physical activity (MVPA levels of Year 7 (age 11–12 girls through a dance-based after-school intervention. The intervention was delivered in nine schools and consisted of up to forty after-school dance sessions. This paper reports on the main findings from the detailed process evaluation that was conducted. Methods Quantitative and qualitative data were collected from intervention schools. Dose and fidelity were reported by dance instructors at every session. Intervention dose was defined as attending two thirds of sessions and was measured by attendance registers. Fidelity to the intervention manual was reported by dance instructors. On four randomly-selected occasions, participants reported their perceived level of exertion and enjoyment. Reasons for non-attendance were self-reported at the end of the intervention. Semi-structured interviews were conducted with all dance instructors who delivered the intervention (n = 10 and school contacts (n = 9 in intervention schools. A focus group was conducted with girls who participated in each intervention school (n = 9. Results The study did not affect girls’ MVPA. An average of 31.7 girls participated in each school, with 9.1 per school receiving the intervention dose. Mean attendance and instructors’ fidelity to the intervention manual decreased over time. The decline in attendance was largely attributed to extraneous factors common to after-school activities. Qualitative data suggest that the training and intervention manual were helpful to most instructors. Participant ratings of session enjoyment were high but perceived exertion was low, however, girls found parts of the intervention challenging. Conclusions The intervention was enjoyed by participants. Attendance at the intervention sessions was low but typical of after

  20. Communitarian educative proposal with robotics: evaluation and learning process outcomes

    Directory of Open Access Journals (Sweden)

    María Dolores Castro Rojas

    2012-07-01

    Full Text Available Normal.dotm 0 0 1 193 1102 Universidad de Salamanca 9 2 1353 12.0 0 false 18 pt 18 pt 0 0 false false false /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-size:12.0pt; font-family:"Times New Roman"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin;} The project seeks to expand young people´s educative horizons that live in conditions of poverty and social risk, by means of an innovative didactic proposal integrating robotics. In this way the participants design, construct and program prototypes in real situations giving them new ways to experiment and share a significant experience. Their building representations are constructed with mechanical LEGO bricks and controlled by iconographic language (Robolab 2, 9. In fact, it was developed in three communitarian centers, which are no formal centers of schooling, located in urban marginal communities. As part of the evaluative process it was observed that students might be much likely to work in groups to represent different environments or conventional events, integrating different mechanical systems to drive their robotics prototypes. Thus, students may incorporate automatic responses, as well as programming structures such as multitask, conditional loops, time control and use of sensors. For many young students of these communities there were over and over again constant social difficulties such as teamwork, lack of socialization skills and deficient formative experiences that we must pay attention to which ideas from

  1. Hydrogeophysical evaluation of vegetation influence on ecohydrological processes

    Science.gov (United States)

    Sharma Acharya, Bharat

    Understanding the spatio-temporal heterogeneity of ecohydrological processes at the soil-plant interface and through the vadose zone is necessary to understand soil, vegetation and climate relations for land use and water resource management and planning in the south-central Great Plains, USA. We calibrated and validated a frequency domain dielectric sensor to quantify litter water content to estimate litter interception of precipitation in situ. Results from 6-months in situ measurement showed that the litter interception of a closed canopy redcedar woodland accounted for about 10% of gross rainfall, constituting a substantial component of the water budget in a sub-humid environment. Time-lapse electrical resistivity imaging was used to track deep moisture dynamics in a tallgrass prairie, prairie encroached by redcedar, closed-canopy redcedar woodland, and oak forest, and to evaluate subsurface flow in the tallgrass prairie with a thin soil over porous bedrock. Results indicated vegetation induced changes in the vertical soil moisture profile, increased spatial-temporal variability in root zone hydraulic conductivity under redcedar encroachment, two-layered moisture migration profiles, and subsurface lateral flow in the tallgrass prairie. Lateral flow was confirmed by short term temporal ERI that tracked movement of water from a berm infiltrometer. Water level from shallow monitoring wells showed higher water levels in the tallgrass prairie than in the redcedar woodland, which suggests that woody plants can decrease the water table in a perched aquifer by a significant amount. Mean soil chloride content varied between 5 to 162 mg L-1 in the tallgrass prairie and 88 to 612 mg L-1 in the prairie encroached by redcedar. Higher soil chloride concentrations under redcedar encroachment indicate reduced percolation and groundwater recharge potential associated with woody plant encroachment. The estimated deep drainage rate was 9.0 mm and 0.30 mm in the tallgrass prairie

  2. Teenagers Poor Readers: Evaluation of Basic Cognitive Process

    Directory of Open Access Journals (Sweden)

    Rosa del Carmen Flores Macías

    2015-04-01

    Full Text Available The present study aims to investigate the cognitive processes associated with reading difficulties of teenage poor readers. Several studies suggest that this population presents a poor comprehension, despite reading the words properly and have good phonological skills (which distinguishes them from a population with dyslexia. With a comparative cross-sectional design the Sicole-R multimedia battery, which assesses basic cognitive processes related to reading, was applied to participants. Results indicate that poor reader students exhibit a lower performance than normal readers in phonological awareness, orthographic processing and processing syntax, although only the latter comparison was statistically significant.

  3. Controlling the Usability Evaluation Process under Varying Defect Visibility

    NARCIS (Netherlands)

    Schmettow, Martin; Blackwell, Alan F.

    2009-01-01

    In cases where usability is a mission critical system quality it is becoming essential to know whether an evaluation study has identified the majority of existing defects. Previous work has shown that procedures for estimating the progress of evaluation studies have to account for variation in

  4. The Teaching Evaluation Process: Segmentation of Marketing Students.

    Science.gov (United States)

    Yau, Oliver H. M.; Kwan, Wayne

    1993-01-01

    A study applied the concept of market segmentation to student evaluation of college teaching, by assessing whether there exist several segments of students and how this relates to their evaluation of faculty. Subjects were 156 Australian undergraduate business administration students. Results suggest segments do exist, with different expectations…

  5. The Effect of Writing on Students' Argument-Evaluation Processes.

    Science.gov (United States)

    Hill, Charles A.

    A study examined the influence of two different writing tasks on the ways in which students evaluate arguments on one controversial issue. Subjects, 20 first-year college students, evaluated 2 argumentative articles on the issue of drug legalization. Subjects rated the strength of the argument of each paragraph as they read. Ten of the subjects…

  6. Preliminary evaluation of alternative waste form solidification processes. Volume I. Identification of the processes

    International Nuclear Information System (INIS)

    Treat, R.L.; Nesbitt, J.F.; Blair, H.T.; Carter, J.G.; Gorton, P.S.; Partain, W.L.; Timmerman, C.L.

    1980-04-01

    This document contains preconceptual design data on 11 processes for the solidification and isolation of nuclear high-level liquid wastes (HLLW). The processes are: in-can glass melting (ICGM) process, joule-heated glass melting (JHGM) process, glass-ceramic (GC) process, marbles-in-lead (MIL) matrix process, supercalcine pellets-in-metal (SCPIM) matrix process, pyrolytic-carbon coated pellets-in-metal (PCCPIM) matrix process, supercalcine hot-isostatic-pressing (SCHIP) process, SYNROC hot-isostatic-pressing (SYNROC HIP) process, titanate process, concrete process, and cermet process. For the purposes of this study, it was assumed that each of the solidification processes is capable of handling similar amounts of HLLW generated in a production-sized fuel reprocessing plant. It was also assumed that each of the processes would be enclosed in a shielded canyon or cells within a waste facility located at the fuel reprocessing plant. Finally, it was assumed that all of the processes would be subject to the same set of regulations, codes and standards. Each of the solidification processes converts waste into forms that may be acceptable for geological disposal. Each process begins with the receipt of HLLW from the fuel reprocessing plant. In this study, it was assumed that the original composition of the HLLW would be the same for each process. The process ends when the different waste forms are enclosed in canisters or containers that are acceptable for interim storage. Overviews of each of the 11 processes and the bases used for their identification are presented in the first part of this report. Each process, including its equipment and its requirements, is covered in more detail in Appendices A through K. Pertinent information on the current state of the art and the research and development required for the implementation of each process are also noted in the appendices

  7. Catchments as heterogeneous and multi-species reactors: An integral approach for identifying biogeochemical hot-spots at the catchment scale

    Science.gov (United States)

    Weyer, Christina; Peiffer, Stefan; Schulze, Kerstin; Borken, Werner; Lischeid, Gunnar

    2014-11-01

    From a biogeochemical perspective, catchments can be regarded as reactors that transform the input of various substances via precipitation or deposition as they pass through soils and aquifers towards draining streams. Understanding and modeling the variability of solute concentrations in catchment waters require the identification of the prevailing processes, determining their respective contribution to the observed transformation of substances, and the localization of "hot spots", that is, the most reactive areas of catchments. For this study, we applied a non-linear variant of the Principle Component Analysis, the Isometric Feature Mapping (Isomap), to a data set composed of 1686 soil solution, groundwater and stream water samples and 16 variables (Al, Ca, Cl, Fe, K, Mg, Mn, Na, NH4, NO3, SO4, total S, Si, DOC, electric conductivity and pH values) from the Lehstenbach catchment in Germany. The aim was (i) to assess the contribution of the prevailing biogeochemical processes to the variability of solute concentrations in water samples taken from soils, in groundwater and in stream water in a catchment and (ii) to identify hot spots at the catchment scale with respect to 16 solutes along different flow paths. The first three dimensions of the Isomap analysis explained 48%, 30% and 11%, respectively, i.e. 89% of the variance in the data set. Scores of the first three dimensions could be ascribed to three predominating bundles of biogeochemical processes: (i) redox processes, (ii) acid-induced podzolization, and (iii) weathering processes. In general, the upper 1 m topsoil layer could be considered as hot spots along flow paths from upslope soils and in the wetland, although with varying extents for the different prevailing biogeochemical processes. Nearly 67% and 97% of the variance with respect to redox processes and acid induced podzolization could be traced back to hot spots, respectively, representing less than 2% of the total spatial volume of the catchment

  8. Wastewater injection, aquifer biogeochemical reactions, and resultant groundwater N fluxes to coastal waters: Kā'anapali, Maui, Hawai'i.

    Science.gov (United States)

    Fackrell, Joseph K; Glenn, Craig R; Popp, Brian N; Whittier, Robert B; Dulai, Henrietta

    2016-09-15

    We utilize N and C species concentration data along with δ(15)N values of NO3(-) and δ(13)C values of dissolved inorganic C to evaluate the stoichiometry of biogeochemical reactions (mineralization, nitrification, anammox, and denitrification) occurring within a subsurface wastewater plume that originates as treated wastewater injection and enters the coastal waters of Maui as submarine groundwater discharge. Additionally, we compare wastewater effluent time-series data, injection rates, and treatment history with submarine spring discharge time-series data. We find that heterotrophic denitrification is the primary mechanism of N loss within the groundwater plume and that chlorination for pathogen disinfection suppresses microbial activity in the aquifer responsible for N loss, resulting in increased coastal ocean N loading. Replacement of chlorination with UV disinfection may restore biogeochemical reactions responsible for N loss within the aquifer and return N-attenuating conditions in the effluent plume, reducing N loading to coastal waters. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. A Critical Evaluation and Framework of Business Process Improvement Methods

    NARCIS (Netherlands)

    Vanwersch, R.J.B.; Shahzad, K.; Vanderfeesten, I.; Vanhaecht, K.; Grefen, P.; Pintelon, L.M.; Mendling, J.; van Merode, G.G.; Reijers, H.A.

    2016-01-01

    The redesign of business processes has a huge potential in terms of reducing costs and throughput times, as well as improving customer satisfaction. Despite rapid developments in the business process management discipline during the last decade, a comprehensive overview of the options to

  10. Beryllium. Evaluation of beryllium hydroxide industrial processes. Pt. 3

    International Nuclear Information System (INIS)

    Lires, O.A.; Delfino, C.A.; Botbol, J.

    1991-01-01

    This work continues the 'Beryllium' series. It is a historical review of different industrial processes of beryllium hydroxide obtention from beryllium ores. Flowsheats and operative parameters of five plants are provided. These plants (Degussa, Brush Beryllium Co., Beryllium Corp., Murex Ltd., SAPPI) were selected as representative samples of diverse commercial processes in different countries. (Author) [es

  11. A Survey on Evaluation Factors for Business Process Management Technology

    NARCIS (Netherlands)

    Mutschler, B.B.; Reichert, M.U.

    2006-01-01

    Estimating the value of business process management (BPM) technology is a difficult task to accomplish. Computerized business processes have a strong impact on an organization, and BPM projects have a long-term cost amortization. To systematically analyze BPM technology from an economic-driven

  12. Neuro-fuzzy model for evaluating the performance of processes ...

    Indian Academy of Sciences (India)

    In this work an Adaptive Neuro-Fuzzy Inference System (ANFIS) was used to model the periodic performance of some multi-input single-output (MISO) processes, namely: brewery operations (case study 1) and soap production (case study 2) processes. Two ANFIS models were developed to model the performance of the ...

  13. System evaluation of offshore platforms with gas liquefaction processes

    DEFF Research Database (Denmark)

    Nguyen, Tuong-Van; de Oliveira Júnior, Silvio

    2018-01-01

    Abstract Floating, production, storage and offloading plants are facilities used for offshore processing of hydrocarbons in remote locations. At present, the produced gas is injected back into the reservoir instead of being exported. The implementation of refrigeration processes offshore for liqu....... It is therefore essential to conduct a careful analysis of the trade-off between the capital costs and operating revenues for such options....... for liquefying natural gas provides the opportunity to monetize offshore gas resources. The present work analyzes the performance of offshore platforms, from the oil processing to the gas liquefaction system. Different feed compositions, system layouts and liquefaction processes are considered. Potential system...... improvements are discussed based on an energy and exergy analysis. Compared to a standard platform where gas is directly injected into the reservoir, the total power consumption increases by up to 50%, and the exergy destruction within the processing plant doubles when a liquefaction system is installed...

  14. A method to evaluate process performance by integrating time and resources

    Science.gov (United States)

    Wang, Yu; Wei, Qingjie; Jin, Shuang

    2017-06-01

    The purpose of process mining is to improve the existing process of the enterprise, so how to measure the performance of the process is particularly important. However, the current research on the performance evaluation method is still insufficient. The main methods of evaluation are mainly using time or resource. These basic statistics cannot evaluate process performance very well. In this paper, a method of evaluating the performance of the process based on time dimension and resource dimension is proposed. This method can be used to measure the utilization and redundancy of resources in the process. This paper will introduce the design principle and formula of the evaluation algorithm. Then, the design and the implementation of the evaluation method will be introduced. Finally, we will use the evaluating method to analyse the event log from a telephone maintenance process and propose an optimization plan.

  15. Reestablishing the Dominance of Biogeochemical Pathways for Reducing Downstream Nutrient Losses from Aged Impounded Features

    Science.gov (United States)

    Shukla, S.; Shukla, A.

    2017-12-01

    Water and phosphorus (P) dynamics and loss pathways at two stormwater impoundments (SIs) were analyzed using measured fluxes between 2008 and 2011. These SIs are a decade old. Analyses of water and P budgets along with the discernment of various P pools and characterization of the intermediary processes revealed that soil adsorption and plant uptake are secondary to volume reduction apropos of P treatment. At one site, extreme wet conditions in a year combined with soil P saturation resulted in it being a P source rather than a sink. The impoundment (SI-1) discharged 12% more P than incoming due to soil P desorption, a consequence of dilution of incoming stormwater with large water input from an extreme tropical rain event. The second impoundment (SI-2) was a consistent sink of P; 55% and 95% of the incoming total P was retained in the two years, mainly as a result of 49% and 84% volume retention, respectively. Analysis of plant available aluminum, iron, and phosphorus showed the surface soil to be P saturated and at risk of releasing P to a limit of environmental concern. These results when seen in light of more frequent extreme precipitation events under the changed climate scenario call for alternatives to revive the role of biogeochemical processes in P treatment because volume reduction may not always be the viable option, especially for wet conditions. Aboveground biomass harvesting and removal was evaluated to transform the SIs from a frequent P source to sink and maintain the long-term sink functions of the SIs. Use of harvested biomass as a source of nutrients (N and P) and carbon to agricultural soil can result in beneficial use of biomass and offset the cost of harvesting. Other avenues such as altering the hydrology of the SIs by compartmentalizing the system and increasing the storage were also explored for short-term benefits. Results provided a combination of hydraulic and biochemical options for achieving long-term water and nutrient retentions in

  16. Deep water convection and biogeochemical cycling of carbon in the Northern North Atlantic

    International Nuclear Information System (INIS)

    Buch, E.; Gissel Nielsen, T.; Lundsgaard, C.; Bendtsen, J.

    2001-01-01

    production and export of DOC (Dissolved Organic Carbon) and the role of UV radiation on biological productivity and DOC mineralization are in focus. The biogeochemical results are implemented in general circulation models in order to evaluate the role of the studied processes on the oceanic carbon cycling. (LN)

  17. Modeling biogeochemical reactive transport in a fracture zone

    International Nuclear Information System (INIS)

    Molinero, Jorge; Samper, Javier; Yang, Chan Bing; Zhang, Guoxiang; Guoxiang, Zhang

    2005-01-01

    A coupled model of groundwater flow, reactive solute transport and microbial processes for a fracture zone of the Aspo site at Sweden is presented. This is the model of the so-called Redox Zone Experiment aimed at evaluating the effects of tunnel construction on the geochemical conditions prevailing in a fracture granite. It is found that a model accounting for microbially-mediated geochemical processes is able to reproduce the unexpected measured increasing trends of dissolved sulfate and bicarbonate. The model is also useful for testing hypotheses regarding the role of microbial processes and evaluating the sensitivity of model results to changes in biochemical parameters

  18. Correlating phospholipid fatty acids (PLFA) in a landfill leachate polluted aquifer with biogeochemical factors by multivariate statistical methods

    DEFF Research Database (Denmark)

    Ludvigsen, Liselotte; Albrechtsen, Hans-Jørgen; Rootzén, Helle

    1997-01-01

    . Partial least square analysis related the phospholipid fatty acids data to the biogeochemical parameters assuming linear relationships. After selection of the optimal phospholipid fatty acid combination by genetic algorithms, good partial least squares models with low prediction errors were gained...... effect and to redox processes and the second principal component described the geological and geochemical features of the samples. Dependent on the data transformation of the phospholipid fatty acid profiles in either absolute concentrations (logarithm transformed) or in mol% of total phospholipid fatty...... primarily between the biogeochemical parameters describing total contents of carbon, pH and chloride. The models predicting specific activity in terms of, e.g., sulfate reduction activity in a sample had relatively higher prediction errors and low correlation coefficients. This indicates...

  19. Nutrient dynamics, transfer and retention along the aquatic continuum from land to ocean: towards integration of ecological and biogeochemical models

    Directory of Open Access Journals (Sweden)

    A. F. Bouwman

    2013-01-01

    Full Text Available In river basins, soils, groundwater, riparian zones and floodplains, streams, rivers, lakes and reservoirs act as successive filters in which the hydrology, ecology and