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Sample records for water decomposition plant

  1. Nuclear driven water decomposition plant for hydrogen production

    NASA Technical Reports Server (NTRS)

    Parker, G. H.; Brecher, L. E.; Farbman, G. H.

    1976-01-01

    The conceptual design of a hydrogen production plant using a very-high-temperature nuclear reactor (VHTR) to energize a hybrid electrolytic-thermochemical system for water decomposition has been prepared. A graphite-moderated helium-cooled VHTR is used to produce 1850 F gas for electric power generation and 1600 F process heat for the water-decomposition process which uses sulfur compounds and promises performance superior to normal water electrolysis or other published thermochemical processes. The combined cycle operates at an overall thermal efficiency in excess of 45%, and the overall economics of hydrogen production by this plant have been evaluated predicated on a consistent set of economic ground rules. The conceptual design and evaluation efforts have indicated that development of this type of nuclear-driven water-decomposition plant will permit large-scale economic generation of hydrogen in the 1990s.

  2. The Conceptual Design of an Integrated Nuclearhydrogen Production Plant Using the Sulfur Cycle Water Decomposition System

    NASA Technical Reports Server (NTRS)

    Farbman, G. H.

    1976-01-01

    A hydrogen production plant was designed based on a hybrid electrolytic-thermochemical process for decomposing water. The sulfur cycle water decomposition system is driven by a very high temperature nuclear reactor that provides 1,283 K helium working gas. The plant is sized to approximately ten million standard cubic meters per day of electrolytically pure hydrogen and has an overall thermal efficiently of 45.2 percent. The economics of the plant were evaluated using ground rules which include a 1974 cost basis without escalation, financing structure and other economic factors. Taking into account capital, operation, maintenance and nuclear fuel cycle costs, the cost of product hydrogen was calculated at $5.96/std cu m for utility financing. These values are significantly lower than hydrogen costs from conventional water electrolysis plants and competitive with hydrogen from coal gasification plants.

  3. Water Limitation and Plant Inter-specific Competition Reduce Rhizosphere-Induced C Decomposition and Plant N Uptake

    Technology Transfer Automated Retrieval System (TEKTRAN)

    1. Plants can affect soil organic matter decomposition and mineralization through litter inputs, but also more directly through root-microbial interactions (rhizosphere effects). Depending on resource availability and plant species identity, these rhizosphere effects can be positive or negative. To...

  4. Phlogopite Decomposition, Water, and Venus

    NASA Technical Reports Server (NTRS)

    Johnson, N. M.; Fegley, B., Jr.

    2005-01-01

    Venus is a hot and dry planet with a surface temperature of 660 to 740 K and 30 parts per million by volume (ppmv) water vapor in its lower atmosphere. In contrast Earth has an average surface temperature of 288 K and 1-4% water vapor in its troposphere. The hot and dry conditions on Venus led many to speculate that hydrous minerals on the surface of Venus would not be there today even though they might have formed in a potentially wetter past. Thermodynamic calculations predict that many hydrous minerals are unstable under current Venusian conditions. Thermodynamics predicts whether a particular mineral is stable or not, but we need experimental data on the decomposition rate of hydrous minerals to determine if they survive on Venus today. Previously, we determined the decomposition rate of the amphibole tremolite, and found that it could exist for billions of years at current surface conditions. Here, we present our initial results on the decomposition of phlogopite mica, another common hydrous mineral on Earth.

  5. Landscape Plants: Fertilizing & Watering

    E-print Network

    Ishida, Yuko

    Landscape Plants: Fertilizing & Watering Landscape Plants: Fertilizing & Watering Prevent runoff and shrubs, either through directly killing plants or making them more prone to disease. Fertilizer runoff into storm drains pollutes waterways. Maintain plant health and protect water quality by fertilizing

  6. Plant decomposition in wetlands: effects of hydrologic variation in a re-created everglades.

    PubMed

    Serna, Alexandra; Richards, Jennifer H; Scinto, Leonard J

    2013-01-01

    The effects of water depth and flow on marsh plant litter decomposition and soil chemistry were measured in the Loxahatchee Impoundment Landscape Assessment (LILA) facility (Boynton Beach, FL), where macrocosms mimic Everglades ridge-and-slough landscape features. Experiments were conducted in two macrocosms that differed in flow but had ridge, shallow slough, and deep slough habitats that differed in water depth. Decomposition of three common Everglades species, Crantz, Torr., and Aiton, were measured using litter bags incubated in the macrocosms under both wet and dry conditions. Litter decomposition was similar among flow treatments and habitats but differed by species and between wet and dry conditions. Decomposition rates from fastest to slowest were > > litter had more total P than the other two species, confirming the importance of P availability in controlling decomposition in the Everglades. Planted species had no effect on soil nutrient content during the ~4 yr of plant growth. Average water velocities of ~0.5 cm s attained in the flow treatment had no effect on decomposition or soil chemistry. The plant species used in this study are major contributors to Everglades' organic soils, so their decomposition rates can be used to parameterize models for how restoration manipulations will affect soil-building processes and to predict the temporal sequence of landscape responses to these manipulations. The results suggest that longer periods and flows greater than studied here may be necessary to see restoration effects on soil building processes. PMID:23673849

  7. Hydrogen production by the decomposition of water

    DOEpatents

    Hollabaugh, Charles M. (Los Alamos, NM); Bowman, Melvin G. (Los Alamos, NM)

    1981-01-01

    How to produce hydrogen from water was a problem addressed by this invention. The solution employs a combined electrolytical-thermochemical sulfuric acid process. Additionally, high purity sulfuric acid can be produced in the process. Water and SO.sub.2 react in electrolyzer (12) so that hydrogen is produced at the cathode and sulfuric acid is produced at the anode. Then the sulfuric acid is reacted with a particular compound M.sub.r X.sub.s so as to form at least one water insoluble sulfate and at least one water insoluble oxide of molybdenum, tungsten, or boron. Water is removed by filtration; and the sulfate is decomposed in the presence of the oxide in sulfate decomposition zone (21), thus forming SO.sub.3 and reforming M.sub.r X.sub.s. The M.sub.r X.sub.s is recycled to sulfate formation zone (16). If desired, the SO.sub.3 can be decomposed to SO.sub.2 and O.sub.2 ; and the SO.sub.2 can be recycled to electrolyzer (12) to provide a cycle for producing hydrogen.

  8. Tremolite Decomposition and Water on Venus

    NASA Technical Reports Server (NTRS)

    Johnson, N. M.; Fegley, B., Jr.

    2000-01-01

    We present experimental data showing that the decomposition rate of tremolite, a hydrous mineral, is sufficiently slow that it can survive thermal decomposition on Venus over geologic timescales at current and higher surface temperatures.

  9. What drives plant litter decomposition globally? Ecological Monographs?

    E-print Network

    Tennessee, University of

    What drives plant litter decomposition globally? Ecological Monographs? Carri J. LeRoy1,2,3 , Dylan and Evolutionary Biology, University of Tennessee, Knoxville, TN 37996 #12;Abstract - 268 Global leaf-litter) of terrestrial plant litter were reported. For each observation of k, climatic variables such as latitude

  10. Plant species traits are the predominant control on litter decomposition rates within biomes worldwide

    E-print Network

    Minnesota, University of

    LETTER Plant species traits are the predominant control on litter decomposition rates within biomes decomposition rates depend both on climate and the legacy of plant functional traits as litter quality. To quantify the degree to which functional differentiation among species affects their litter decomposition

  11. Metal-induced decomposition of perchlorate in pressurized hot water.

    PubMed

    Hori, Hisao; Sakamoto, Takehiko; Tanabe, Takashi; Kasuya, Miu; Chino, Asako; Wu, Qian; Kannan, Kurunthachalam

    2012-10-01

    Decomposition of perchlorate (ClO(4)(-)) in pressurized hot water (PHW) was investigated. Although ClO(4)(-) demonstrated little reactivity in pure PHW up to 300°C, addition of zerovalent metals to the reaction system enhanced the decomposition of ClO(4)(-) to Cl(-) with an increasing order of activity of (no metal)?Al < Cu < Zn < Ni < Fe: the addition of iron powder led to the most efficient decomposition of ClO(4)(-). When the iron powder was added to an aqueous ClO(4)(-) solution (104 ?M) and the mixture was heated at 150°C, ClO(4)(-) concentration fell below 0.58 ?M (58 ?g L(-1), detection limit of ion chromatography) in 1 h, and Cl(-) was formed with the yield of 85% after 6 h. The decomposition was accompanied by transformation of the zerovalent iron to Fe(3)O(4). This method was successfully used in the decomposition of ClO(4)(-) in a water sample contaminated with this compound, following fireworks display at Albany, New York, USA. PMID:22840541

  12. Author's personal copy Black carbon decomposition under varying water regimes

    E-print Network

    Lehmann, Johannes

    Author's personal copy Black carbon decomposition under varying water regimes Binh Thanh Nguyen investigation. Ó 2009 Elsevier Ltd. All rights reserved. 1. Introduction Black carbon (BC) is a general term Accepted 10 May 2009 Available online 20 May 2009 a b s t r a c t The stability of biomass-derived black

  13. Hydrogen peroxide deposition and decomposition in rain and dew waters

    NASA Astrophysics Data System (ADS)

    Ortiz, Vicky; Angélica Rubio, M.; Lissi, Eduardo A.

    Peroxides and hydrogen peroxide were determined by a fluorometric method in dew and rain collected in the atmosphere of Santiago of Chile city. The measured peroxides comprise hydrogen peroxide (the main component) and peroxides not decomposed by catalase. The collected natural peroxides readily decompose in the natural matrix, rendering difficult an estimation of the values present in real-time. In order to establish the kinetics of the process and the factors that condition their decomposition, the kinetics of the decay at several pHs and/or the presence of metal chelators were followed. The kinetics of hydrogen peroxide decomposition in the water matrix was evaluated employing the natural peroxides or hydrogen peroxide externally added. First-order kinetics was followed, with half decay times ranging from 80 to 2300 min. The addition of Fe(II) in the micromolar range increases the decomposition rate, while lowering the pH (<3) notably reduces the rate of the process. The contribution of metals to the decomposition of the peroxides in the natural waters was confirmed by the reduction in decomposition rate elicited by its treatment with Chelex-100. Dew and rain waters were collected in pre-acidified collectors, rendering values considerably higher than those measured in non-treated collectors. This indicates that acidification can be proposed as an easy procedure to stabilize the samples, reducing its decomposition during collection time and the time elapsed between collection and analysis. The weighted average concentration for total peroxides measured in pre-treated collectors was 5.4 ?M in rains and 2.2 ?M in dews.

  14. Hydroxyl radicals from secondary organic aerosol decomposition in water

    NASA Astrophysics Data System (ADS)

    Tong, H.; Arangio, A. M.; Lakey, P. S. J.; Berkemeier, T.; Liu, F.; Kampf, C. J.; Pöschl, U.; Shiraiwa, M.

    2015-11-01

    We found that ambient and laboratory-generated secondary organic aerosols (SOA) form substantial amounts of OH radicals upon interaction with liquid water, which can be explained by the decomposition of organic hydroperoxides. The molar OH yield from SOA formed by ozonolysis of terpenes (?-pinene, ?-pinene, limonene) is ~ 0.1 % upon extraction with pure water and increases to ~ 1.5 % in the presence of Fe2+ ions due to Fenton-like reactions. Our findings imply that the chemical reactivity and aging of SOA particles is strongly enhanced upon interaction with water and iron. In cloud droplets under dark conditions, SOA decomposition can compete with the classical H2O2 Fenton reaction as the source of OH radicals. Also in the human respiratory tract, the inhalation and deposition of SOA particles may lead to a substantial release of OH radicals, which may contribute to oxidative stress and play an important role in the adverse health effects of atmospheric aerosols.

  15. Effects of hydrology on short term plant decomposition and nutrient content in a re-created Everglades wetland

    NASA Astrophysics Data System (ADS)

    Serna, A.; Richards, J.; Scinto, L.

    2012-12-01

    The effect of water depth and flow on tissue nutrients and decomposition rates of marsh plant species, and soil chemistry in vegetated plots was measured in the Loxahatchee Impoundment Landscape Assessment (LILA) facility in Boynton Beach, Florida, USA. The LILA facility consists of replicated wetland macrocosms that mimic Everglades ridge-and-slough landscape features. The experiments were conducted in two macrocosms that each had three habitats at different water depths (ridge, shallow slough and deep slough) but differed in flow. Decomposition rates of three common Everglades species, Cladium jamaicense (sawgrass), Eleocharis cellulosa (spikerush), and Nymphaea odorata (white water lily), were measured using litter bags incubated during both a wet and dry condition. Litter bag losses were more pronounced under wet conditions, and decomposition rates were not affected by the hydrologic conditions in this experiment, but rather by litter nutrient content and species. Litter nutrient (TC, TN, TP) concentrations varied over time. Species rich in the limiting nutrient (P) in the ecosystem decomposed faster. Therefore, N. odorata decomposed faster than C. jamaicense and E. cellulosa, confirming the importance of P availability in controlling microbial processes in the Everglades. Planted species had no effect on soil nutrient content over the 3 yrs period of plant growth in these plots. Our results have contributed to defining potential flow targets for restoration in Florida's Everglades by showing that average water velocities of 0.5 cm s-1 may not be sufficient to drive ecosystem changes in decomposition rates for the native species and soil chemistry.

  16. Hydrogen production by water decomposition using a combined electrolytic-thermochemical cycle

    NASA Technical Reports Server (NTRS)

    Farbman, G. H.; Brecher, L. E.

    1976-01-01

    A proposed dual-purpose power plant generating nuclear power to provide energy for driving a water decomposition system is described. The entire system, dubbed Sulfur Cycle Water Decomposition System, works on sulfur compounds (sulfuric acid feedstock, sulfur oxides) in a hybrid electrolytic-thermochemical cycle; performance superior to either all-electrolysis systems or presently known all-thermochemical systems is claimed. The 3345 MW(th) graphite-moderated helium-cooled reactor (VHTR - Very High Temperature Reactor) generates both high-temperature heat and electric power for the process; the gas stream at core exit is heated to 1850 F. Reactor operation is described and reactor innards are illustrated. A cost assessment for on-stream performance in the 1990's is optimistic.

  17. Stoichiometry of Microbial Decomposition Priming in Plant Litter and Soil

    NASA Astrophysics Data System (ADS)

    Schaefer, D.; Qiao, N.

    2011-12-01

    Microbial priming is accelerated conversion of plant residues and soil organic carbon to CO2. It is caused by small additions of labile carbon and nitrogen compounds, but microbial stoichiometry suggests that this description is incomplete. The temperature dependence of soil organic carbon cycling models may be related to diffusion of labile resources to microbial cells. Incomplete treatment of stoichiometrically significant elements in these models may also limit their ability to predict carbon fluxes if plant species, diseases or defoliators are affected by climate changes. We explore this by incubating decomposable substrates (leaves, wood, humus and mineral soil) with resources added as dissolved inorganic nitrogen (ammonium and nitrate separately), phosphorus and sugar, added in different amounts and proportions. We measure CO2 production by infrared absorption. Contribution of sugar to CO2 production is assessed by mass spectrometry. High concentrations for each resource are 16X the low, and middle concentrations are 4X the low. The ratios are centered on 200:10:1. We explore C:N:P resource ratios and additions over wide ranges; subsequently to examine narrower ranges of interest. For C:N:P incubations, C and N effects are always significant on CO2 production, with P in only half of the treatments. Literature suggests that leaf-litter decomposition is stimulated by N (occasionally P) additions, but results for soils have been mixed. We find N to be inhibitory only when added in "stoichiometic excess" to added C. Stimulation of microbial respiration is generally strongest with C:N:P additions in "Redfield-like" ratios, but the response is far below linear. Humus has a stronger response to C than do leaves and wood. This is consistent with a chronic energy limitation for soil microbes, even where their environments contain large amounts of total C. For all substrates, the addition of N as nitrate leads to significantly more CO2 than the same amount of ammonium-N. This result was unexpected because nitrate must be reduced (at metabolic cost) before it can be utilized in cells. Possible explanations include relatively less mobility of ammonium in the environment, and enzyme syntheses being more inhibited by ammonium. At least, it suggests that studies treating ammonium and nitrate as equivalent N sources miss important aspects of microbial metabolism. In incubations with only P as an added resource, CO2 production was stimulated in all substrates except leaf, but only with much larger P additions compared to the C:N:P incubations. Previous studies have shown that leaf decomposition can be stimulated by added P, but among these 4 substrates, we suggest that leaves have the highest amounts of available P relative to C. Further studies will be presented, including microbial community assessment by PCR-DGGE. Thus far, we see that stimulation of microbial respiration is greatest when C is added above cellular stoichiometric ratios for N and P, emphasizing energy costs associated with microbial growth and exoenzyme synthesis. In addition, the most effective C:N:P resource ratios for decomposition vary widely among substrates. These results can contribute to the development of decomposition and soil organic carbon models with greater biological realism. .

  18. Decomposition

    USGS Publications Warehouse

    Middleton, Beth A.

    2014-01-01

    A cornerstone of ecosystem ecology, decomposition was recognized as a fundamental process driving the exchange of energy in ecosystems by early ecologists such as Lindeman 1942 and Odum 1960). In the history of ecology, studies of decomposition were incorporated into the International Biological Program in the 1960s to compare the nature of organic matter breakdown in various ecosystem types. Such studies still have an important role in ecological studies of today. More recent refinements have brought debates on the relative role microbes, invertebrates and environment in the breakdown and release of carbon into the atmosphere, as well as how nutrient cycling, production and other ecosystem processes regulated by decomposition may shift with climate change. Therefore, this bibliography examines the primary literature related to organic matter breakdown, but it also explores topics in which decomposition plays a key supporting role including vegetation composition, latitudinal gradients, altered ecosystems, anthropogenic impacts, carbon storage, and climate change models. Knowledge of these topics is relevant to both the study of ecosystem ecology as well projections of future conditions for human societies.

  19. Elevated CO2 and plant species diversity interact to slow root decomposition

    SciTech Connect

    De Graaff, Marie-Anne; Schadt, Christopher Warren; Rula, Kelly L; Six, Johan W U A; Schweitzer, Jennifer A; Classen, Aimee T

    2011-01-01

    Changes in plant species diversity can result in synergistic increases in decomposition rates, while elevated atmospheric CO2 can slow the decomposition rates; yet it remains unclear how diversity and changes in atmospheric CO2 may interact to alter root decomposition. To investigate how elevated CO2 interacts with changes in root-litter diversity to alter decomposition rates, we conducted a 120-day laboratory incubation. Roots from three species (Trifolium repens, Lespedeza cuneata, and Festuca pratense) grown under ambient or elevated CO2 were incubated individually or in combination in soils that were exposed to ambient or elevated CO2 for five years. Our experiment resulted in two main findings: (1) Roots from T. repens and L. cuneata, both nitrogen (N) fixers, grown under elevated CO2 treatments had significantly slower decomposition rates than similar roots grown under ambient CO2 treatments; but the decomposition rate of F. pratense roots (a non-N-fixing species) was similar regardless of CO2 treatment. (2) Roots of the three species grown under ambient CO2 and decomposed in combination with each other had faster decomposition rates than when they were decomposed as single species. However, roots of the three species grown under elevated CO2 had similar decomposition rates when they were incubated alone or in combination with other species. These data suggest that if elevated CO2 reduces the root decomposition rate of even a few species in the community, it may slow root decomposition of the entire plant community.

  20. Noise Decomposition in Boiling Water Reactors with Application to Stability Monitoring

    E-print Network

    Pázsit, Imre

    Noise Decomposition in Boiling Water Reactors with Application to Stability Monitoring J. Karlsson and the approximate factorization, elab- oration of a factorization-based flux decomposition is possible. A phenomenological BWR noise model is used here in support of the decomposition technique. The model is also used

  1. Decomposition of tree leaf litter on pavement: implications for urban water quality

    E-print Network

    Thomas, David D.

    Decomposition of tree leaf litter on pavement: implications for urban water quality Sarah E. Hobbie decomposition and nutrient release from leaf litter that falls on impervious surfaces is important environment of the street gutter. We compared decomposition of leaf litter of five street tree species

  2. Soil organic matter decomposition follows plant productivity response to sea-level rise

    NASA Astrophysics Data System (ADS)

    Mueller, Peter; Jensen, Kai; Megonigal, James Patrick

    2015-04-01

    The accumulation of soil organic matter (SOM) is an important mechanism for many tidal wetlands to keep pace with sea-level rise. SOM accumulation is governed by the rates of production and decomposition of organic matter. While plant productivity responses to sea-level rise are well understood, far less is known about the response of SOM decomposition to accelerated sea-level rise. Here we quantified the effects of sea-level rise on SOM decomposition by exposing planted and unplanted tidal marsh monoliths to experimentally manipulated flood duration. The study was performed in a field-based mesocosm facility at the Smithsonian Global Change Research Wetland, a micro tidal brackish marsh in Maryland, US. SOM decomposition was quantified as CO2 efflux, with plant- and SOM-derived CO2 separated using a stable carbon isotope approach. Despite the dogma that decomposition rates are inversely related to flooding, SOM mineralization was not sensitive to varying flood duration over a 35 cm range in surface elevation in unplanted mesocoms. In the presence of plants, decomposition rates were strongly and positively related to aboveground biomass (p?0.01, R2?0.59). We conclude that rates of soil carbon loss through decomposition are driven by plant responses to sea level in this intensively studied tidal marsh. If our result applies more generally to tidal wetlands, it has important implications for modeling carbon sequestration and marsh accretion in response to accelerated sea-level rise.

  3. Properties of Soil Pore Space Regulate Pathways of Plant Residue Decomposition and Community Structure of Associated Bacteria

    PubMed Central

    Negassa, Wakene C.; Guber, Andrey K.; Kravchenko, Alexandra N.; Marsh, Terence L.; Hildebrandt, Britton; Rivers, Mark L.

    2015-01-01

    Physical protection of soil carbon (C) is one of the important components of C storage. However, its exact mechanisms are still not sufficiently lucid. The goal of this study was to explore the influence of soil structure, that is, soil pore spatial arrangements, with and without presence of plant residue on (i) decomposition of added plant residue, (ii) CO2 emission from soil, and (iii) structure of soil bacterial communities. The study consisted of several soil incubation experiments with samples of contrasting pore characteristics with/without plant residue, accompanied by X-ray micro-tomographic analyses of soil pores and by microbial community analysis of amplified 16S–18S rRNA genes via pyrosequencing. We observed that in the samples with substantial presence of air-filled well-connected large (>30 µm) pores, 75–80% of the added plant residue was decomposed, cumulative CO2 emission constituted 1,200 µm C g-1 soil, and movement of C from decomposing plant residue into adjacent soil was insignificant. In the samples with greater abundance of water-filled small pores, 60% of the added plant residue was decomposed, cumulative CO2 emission constituted 2,000 µm C g-1 soil, and the movement of residue C into adjacent soil was substantial. In the absence of plant residue the influence of pore characteristics on CO2 emission, that is on decomposition of the native soil organic C, was negligible. The microbial communities on the plant residue in the samples with large pores had more microbial groups known to be cellulose decomposers, that is, Bacteroidetes, Proteobacteria, Actinobacteria, and Firmicutes, while a number of oligotrophic Acidobacteria groups were more abundant on the plant residue from the samples with small pores. This study provides the first experimental evidence that characteristics of soil pores and their air/water flow status determine the phylogenetic composition of the local microbial community and directions and magnitudes of soil C decomposition processes. PMID:25909444

  4. Properties of soil pore space regulate pathways of plant residue decomposition and community structure of associated bacteria

    SciTech Connect

    Negassa, Wakene C.; Guber, Andrey K.; Kravchenko, Alexandra N.; Marsh, Terence L.; Hildebrandt, Britton; Rivers, Mark L.

    2015-07-01

    Physical protection of soil carbon (C) is one of the important components of C storage. However, its exact mechanisms are still not sufficiently lucid. The goal of this study was to explore the influence of soil structure, that is, soil pore spatial arrangements, with and without presence of plant residue on (i) decomposition of added plant residue, (ii) CO? emission from soil, and (iii) structure of soil bacterial communities. The study consisted of several soil incubation experiments with samples of contrasting pore characteristics with/without plant residue, accompanied by X-ray micro-tomographic analyses of soil pores and by microbial community analysis of amplified 16S–18S rRNA genes via pyrosequencing. We observed that in the samples with substantial presence of air-filled well-connected large (>30 µm) pores, 75–80% of the added plant residue was decomposed, cumulative CO? emission constituted 1,200 µm C g?¹ soil, and movement of C from decomposing plant residue into adjacent soil was insignificant. In the samples with greater abundance of water-filled small pores, 60% of the added plant residue was decomposed, cumulative CO? emission constituted 2,000 µm C g?¹ soil, and the movement of residue C into adjacent soil was substantial. In the absence of plant residue the influence of pore characteristics on CO? emission, that is on decomposition of the native soil organic C, was negligible. The microbial communities on the plant residue in the samples with large pores had more microbial groups known to be cellulose decomposers, that is, Bacteroidetes, Proteobacteria, Actinobacteria, and Firmicutes, while a number of oligotrophic Acidobacteria groups were more abundant on the plant residue from the samples with small pores. This study provides the first experimental evidence that characteristics of soil pores and their air/water flow status determine the phylogenetic composition of the local microbial community and directions and magnitudes of soil C decomposition processes.

  5. Properties of soil pore space regulate pathways of plant residue decomposition and community structure of associated bacteria

    DOE PAGESBeta

    Negassa, Wakene C.; Guber, Andrey K.; Kravchenko, Alexandra N.; Marsh, Terence L.; Hildebrandt, Britton; Rivers, Mark L.

    2015-07-01

    Physical protection of soil carbon (C) is one of the important components of C storage. However, its exact mechanisms are still not sufficiently lucid. The goal of this study was to explore the influence of soil structure, that is, soil pore spatial arrangements, with and without presence of plant residue on (i) decomposition of added plant residue, (ii) CO? emission from soil, and (iii) structure of soil bacterial communities. The study consisted of several soil incubation experiments with samples of contrasting pore characteristics with/without plant residue, accompanied by X-ray micro-tomographic analyses of soil pores and by microbial community analysis ofmore »amplified 16S–18S rRNA genes via pyrosequencing. We observed that in the samples with substantial presence of air-filled well-connected large (>30 µm) pores, 75–80% of the added plant residue was decomposed, cumulative CO? emission constituted 1,200 µm C g?¹ soil, and movement of C from decomposing plant residue into adjacent soil was insignificant. In the samples with greater abundance of water-filled small pores, 60% of the added plant residue was decomposed, cumulative CO? emission constituted 2,000 µm C g?¹ soil, and the movement of residue C into adjacent soil was substantial. In the absence of plant residue the influence of pore characteristics on CO? emission, that is on decomposition of the native soil organic C, was negligible. The microbial communities on the plant residue in the samples with large pores had more microbial groups known to be cellulose decomposers, that is, Bacteroidetes, Proteobacteria, Actinobacteria, and Firmicutes, while a number of oligotrophic Acidobacteria groups were more abundant on the plant residue from the samples with small pores. This study provides the first experimental evidence that characteristics of soil pores and their air/water flow status determine the phylogenetic composition of the local microbial community and directions and magnitudes of soil C decomposition processes.« less

  6. Plant roots alter microbial potential for mediation of soil organic carbon decomposition

    NASA Astrophysics Data System (ADS)

    Firestone, M.; Shi, S.; Herman, D.; He, Z.; Zhou, J.

    2014-12-01

    Plant root regulation of soil organic carbon (SOC) decomposition is a key controller of terrestrial C-cycling. Although many studies have tested possible mechanisms underlying plant "priming" of decomposition, few have investigated the microbial mediators of decomposition, which can be greatly influenced by plant activities. Here we examined effects of Avena fatua roots on decomposition of 13C-labeled root litter in a California grassland soil over two simulated growing-seasons. The presence of plant roots consistently suppressed rates of litter decomposition. Reduction of inorganic nitrogen (N) concentration in soil reduced but did not completely relieve this suppressive effect. The presence of plants significantly altered the abundance, composition and functional potential of microbial communities. Significantly higher signal intensities of genes capable of degrading low molecular weight organic compounds (e.g., glucose, formate and malate) were observed in microbial communities from planted soils, while microorganisms in unplanted soils had higher relative abundances of genes involved in degradation of some macromolecules (e.g., hemicellulose and lignin). Additionally, compared to unplanted soils, microbial communities from planted soils had higher signal intensities of proV and proW, suggesting microbial osmotic stress in planted soils. Possible mechanisms for the observed inhibition of decomposition are 1) microbes preferentially using simple substrates from root exudates and 2) soil drying by plant evapotranspiration impairing microbial activity. We propose a simple data-based model suggesting that the impacts of roots, the soil environment, and microbial community composition on decomposition processes result from impacts of these factors on the soil microbial functional gene potential.

  7. Labile soil carbon inputs mediate the soil microbial community composition and plant residue decomposition rates

    SciTech Connect

    De Graaff, Marie-Anne; Classen, Aimee T; Castro Gonzalez, Hector F; Schadt, Christopher Warren

    2010-01-01

    Root carbon (C) inputs may regulate decomposition rates in soil, and in this study we ask: how do labile C inputs regulate decomposition of plant residues, and soil microbial communities? In a 14 d laboratory incubation, we added C compounds often found in root exudates in seven different concentrations (0, 0.7, 1.4, 3.6, 7.2, 14.4 and 21.7 mg C g{sup -1} soil) to soils amended with and without {sup 13}C-labeled plant residue. We measured CO{sub 2} respiration and shifts in relative fungal and bacterial rRNA gene copy numbers using quantitative polymerase chain reaction (qPCR). Increased labile C input enhanced total C respiration, but only addition of C at low concentrations (0.7 mg C g{sup -1}) stimulated plant residue decomposition (+2%). Intermediate concentrations (1.4, 3.6 mg C g{sup -1}) had no impact on plant residue decomposition, while greater concentrations of C (> 7.2 mg C g{sup -1}) reduced decomposition (-50%). Concurrently, high exudate concentrations (> 3.6 mg C g{sup -1}) increased fungal and bacterial gene copy numbers, whereas low exudate concentrations (< 3.6 mg C g{sup -1}) increased metabolic activity rather than gene copy numbers. These results underscore that labile soil C inputs can regulate decomposition of more recalcitrant soil C by controlling the activity and relative abundance of fungi and bacteria.

  8. Water Filtration Using Plant Xylem

    PubMed Central

    Chambers, Valerie; Venkatesh, Varsha; Karnik, Rohit

    2014-01-01

    Effective point-of-use devices for providing safe drinking water are urgently needed to reduce the global burden of waterborne disease. Here we show that plant xylem from the sapwood of coniferous trees – a readily available, inexpensive, biodegradable, and disposable material – can remove bacteria from water by simple pressure-driven filtration. Approximately 3 cm3 of sapwood can filter water at the rate of several liters per day, sufficient to meet the clean drinking water needs of one person. The results demonstrate the potential of plant xylem to address the need for pathogen-free drinking water in developing countries and resource-limited settings. PMID:24587134

  9. Water filtration using plant xylem.

    PubMed

    Boutilier, Michael S H; Lee, Jongho; Chambers, Valerie; Venkatesh, Varsha; Karnik, Rohit

    2014-01-01

    Effective point-of-use devices for providing safe drinking water are urgently needed to reduce the global burden of waterborne disease. Here we show that plant xylem from the sapwood of coniferous trees--a readily available, inexpensive, biodegradable, and disposable material--can remove bacteria from water by simple pressure-driven filtration. Approximately 3 cm(3) of sapwood can filter water at the rate of several liters per day, sufficient to meet the clean drinking water needs of one person. The results demonstrate the potential of plant xylem to address the need for pathogen-free drinking water in developing countries and resource-limited settings. PMID:24587134

  10. Water Filtration Using Plant Xylem

    E-print Network

    Lee, Jongho; Chambers, Valerie; Venkatesh, Varsha; Karnik, Rohit

    2013-01-01

    Effective point-of-use devices for providing safe drinking water are urgently needed to reduce the global burden of waterborne disease. Here we show that plant xylem from the sapwood of coniferous trees - a readily available, inexpensive, biodegradable, and disposable material - can remove bacteria from water by simple pressure-driven filtration. Approximately 3 cm3 of sapwood can filter water at the rate of several liters per day, sufficient to meet the clean drinking water needs of one person. The results demonstrate the potential of plant xylem to address the need for pathogen-free drinking water in developing countries and resource-limited settings.

  11. Manganese Cycling in a Long-term Plant Litter Decomposition Time Series

    NASA Astrophysics Data System (ADS)

    Keiluweit, M.; Nico, P. S.; Kleber, M.; Bougoure, J.; Harmon, M. E.; Pett-Ridge, J.

    2012-12-01

    Climate change is predicted to affect the chemical composition of plant litter, and global warming may increase microbial and enzymatic activity, with uncertain consequences for litter decomposition rates in soils. This uncertainty has highlighted the need to better understand the controls on litter decomposition rates and pathways. A key controlling processes that is poorly understood is the coupling between decomposition pathways and the inorganic resources available in fresh litter or the underlying soil. For example, a strong correlation was established between the concentration of manganese (Mn) in needle litter and the degradation of litter lignocellulose across boreal forest ecosystems, suggesting that litter decomposition proceeds more efficiently in the presence of Mn. There is good reason to assume that this is due to the critical role of Mn(III)-ligand complexes acting as potent oxidizers in the fungal decomposition of lignocellulose. Here we investigated how litter decomposing organisms redistribute and repurpose the Mn inherently present in fresh plant litter in order to enhance decomposition. For this purpose, we used two 7-year litter decomposition time series collected at sites at the H.J. Andrews Experimental Forest with widely differing decomposition rates. Spatially-resolved X-ray absorption spectroscopy and wet-chemical extractions were used to track pathways of microbially-mediated Mn transport and associated changes in its speciation in each annual litter layer. The cycling of Mn and other metal cations (e.g., Ca and Fe) was then related to changes in the litter chemistry as documented by 13C TMAH and FTIR. Our results show that, as litter decomposition progresses, reduced Mn in the vascular system of fresh needles is transformed into oxidized forms concentrated in Mn oxide precipitates. This transformation of Mn into more reactive forms proceeds faster at the site of greater decomposition. Our imaging data suggests that during this process Mn is redistributed from the vascular system of fresh needles towards lignocellulose-rich cell walls that are being decomposed by fungi.

  12. Metal/metalloid fixation by litter during decomposition affected by silicon availability during plant growth.

    PubMed

    Schaller, Jörg

    2013-03-01

    Organic matter is known to accumulate high amounts of metals/metalloids, enhanced during the process of decomposition by heterotrophic biofilms (with high fixation capacity for metals/metalloids). The colonization by microbes and the decay rate of the organic matter depends on different litter properties. Main litter properties affecting the decomposition of organic matter such as the nutrient ratios and the content of cellulose, lignin and phenols are currently described to be changed by silicon availability. But less is known about the impact of silicon availability during plant growth on elemental fixation during decay. Hence, this research focuses on the impact of silicon availability during plant growth on fixation of 42 elements during litter decay, by controlling the litter properties. The results of this experiment are a significantly higher metal/metalloid accumulation during decomposition of plant litter grown under low silicon availability. This may be explained by the altered litter properties (mainly nutrient content) affecting the microbial decomposition of the litter, the microbial growth on the litter and possibly by the silicon double layer, which is evident in leaf litter with high silicon content and reduces the binding sites for metals/metalloids. Furthermore, this silicon double layer may also reduce the growing biofilm by reducing the availability of carbon compounds at the litter surface and has to be elucidated in further research. Hence, low silicon availability during plant growth enhances the metal/metalloid accumulation into plant litter during aquatic decomposition. PMID:23228909

  13. Water Filtration Using Plant Xylem

    E-print Network

    Boutilier, Michael Stephen Ha

    Effective point-of-use devices for providing safe drinking water are urgently needed to reduce the global burden of waterborne disease. Here we show that plant xylem from the sapwood of coniferous trees – a readily available, ...

  14. Power Plant Water Intake Assessment.

    ERIC Educational Resources Information Center

    Zeitoun, Ibrahim H.; And Others

    1980-01-01

    In order to adequately assess the impact of power plant cooling water intake on an aquatic ecosystem, total ecosystem effects must be considered, rather than merely numbers of impinged or entrained organisms. (Author/RE)

  15. Monitoring power plant water chemistry

    SciTech Connect

    Pocock, F.J.

    1981-01-01

    The objectives and requirements for water quality monitoring in utility power plants are discussed in an overview fashion. This includes the available instrumentation and some discussion of further development work that is needed.

  16. Scale decomposition of atmospheric water budget over West Africa during the monsoon 2006 from NCEP/GFS analyses

    E-print Network

    Roca, Rémy

    Scale decomposition of atmospheric water budget over West Africa during the monsoon 2006 from NCEP the terms of the atmospheric water budget over West Africa using a dedicated decomposition methodology decomposition approach is helpful to clarify the functioning of the water cycle embedded in the monsoon system

  17. Plant transpiration distillation of water

    SciTech Connect

    Virostko, M.K.; Spielberg, J.I.

    1986-01-01

    A project using solar energy and the transpiration of plants for the distillation of water is described. Along with determining which of three plants thrived best growing in a still, the experiment also revealed that the still functioned nearly as well in inclement weather as in fair weather.

  18. Waste Water Plant Operators Manual.

    ERIC Educational Resources Information Center

    Washington State Coordinating Council for Occupational Education, Olympia.

    This manual for sewage treatment plant operators was prepared by a committee of operators, educators, and engineers for use as a reference text and handbook and to serve as a training manual for short course and certification programs. Sewage treatment plant operators have a responsibility in water quality control; they are the principal actors in…

  19. Changes in bacterial and eukaryotic communities during sewage decomposition in Mississippi River water

    EPA Science Inventory

    Microbial decay processes are one of the mechanisms whereby sewage contamination is reduced in the environment. This decomposition process involves a highly complex array of bacterial and eukaryotic communities from both sewage and ambient waters. However, relatively little is kn...

  20. Plants Regulate Soil Organic Matter Decomposition in Response to Sea Level Rise

    NASA Astrophysics Data System (ADS)

    Megonigal, P.; Mueller, P.; Jensen, K.

    2014-12-01

    Tidal wetlands have a large capacity for producing and storing organic matter, making their role in the global carbon budget disproportionate to their land area. Most of the organic matter stored in these systems is in soils where it contributes 2-5 times more to surface accretion than an equal mass of minerals. Soil organic matter (SOM) sequestration is the primary process by which tidal wetlands become perched high in the tidal frame, decreasing their vulnerability to accelerated sea level rise. Plant growth responses to sea level rise are well understood and represented in century-scale forecast models of soil surface elevation change. We understand far less about the response of soil organic matter decomposition to rapid sea level rise. Here we quantified the effects of sea level on SOM decomposition rates by exposing planted and unplanted tidal marsh monoliths to experimentally manipulated flood duration. The study was performed in a field-based mesocosm facility at the Smithsonian's Global Change Research Wetland. SOM decomposition rate was quantified as CO2 efflux, with plant- and SOM-derived CO2 separated with a two end-member ?13C-CO2 model. Despite the dogma that decomposition rates are inversely related to flooding, SOM mineralization was not sensitive to flood duration over a 35 cm range in soil surface elevation. However, decomposition rates were strongly and positively related to aboveground biomass (R2?0.59, p?0.01). We conclude that soil carbon loss through decomposition is driven by plant responses to sea level in this intensively studied tidal marsh. If this result applies more generally to tidal wetlands, it has important implications for modeling soil organic matter and surface elevation change in response to accelerated sea level rise.

  1. Complementary symbiont contributions to plant decomposition in a fungus-farming termite

    E-print Network

    Complementary symbiont contributions to plant decomposition in a fungus-farming termite Michael) Termites normally rely on gut symbionts to decompose organic matter but the Macrotermitinae domesticated enigmatic. We obtained high-quality annotated draft genomes of the termite Macrotermes natalensis, its

  2. Modeling water use at thermoelectric power plants

    E-print Network

    Rutberg, Michael J. (Michael Jacob)

    2012-01-01

    The withdrawal and consumption of water at thermoelectric power plants affects regional ecology and supply security of both water and electricity. The existing field data on US power plant water use, however, is of limited ...

  3. Plant Diversity Impacts Decomposition and Herbivory via Changes in Aboveground Arthropods

    PubMed Central

    Ebeling, Anne; Meyer, Sebastian T.; Abbas, Maike; Eisenhauer, Nico; Hillebrand, Helmut; Lange, Markus; Scherber, Christoph; Vogel, Anja; Weigelt, Alexandra; Weisser, Wolfgang W.

    2014-01-01

    Loss of plant diversity influences essential ecosystem processes as aboveground productivity, and can have cascading effects on the arthropod communities in adjacent trophic levels. However, few studies have examined how those changes in arthropod communities can have additional impacts on ecosystem processes caused by them (e.g. pollination, bioturbation, predation, decomposition, herbivory). Therefore, including arthropod effects in predictions of the impact of plant diversity loss on such ecosystem processes is an important but little studied piece of information. In a grassland biodiversity experiment, we addressed this gap by assessing aboveground decomposer and herbivore communities and linking their abundance and diversity to rates of decomposition and herbivory. Path analyses showed that increasing plant diversity led to higher abundance and diversity of decomposing arthropods through higher plant biomass. Higher species richness of decomposers, in turn, enhanced decomposition. Similarly, species-rich plant communities hosted a higher abundance and diversity of herbivores through elevated plant biomass and C:N ratio, leading to higher herbivory rates. Integrating trophic interactions into the study of biodiversity effects is required to understand the multiple pathways by which biodiversity affects ecosystem functioning. PMID:25226237

  4. Plant diversity impacts decomposition and herbivory via changes in aboveground arthropods.

    PubMed

    Ebeling, Anne; Meyer, Sebastian T; Abbas, Maike; Eisenhauer, Nico; Hillebrand, Helmut; Lange, Markus; Scherber, Christoph; Vogel, Anja; Weigelt, Alexandra; Weisser, Wolfgang W

    2014-01-01

    Loss of plant diversity influences essential ecosystem processes as aboveground productivity, and can have cascading effects on the arthropod communities in adjacent trophic levels. However, few studies have examined how those changes in arthropod communities can have additional impacts on ecosystem processes caused by them (e.g. pollination, bioturbation, predation, decomposition, herbivory). Therefore, including arthropod effects in predictions of the impact of plant diversity loss on such ecosystem processes is an important but little studied piece of information. In a grassland biodiversity experiment, we addressed this gap by assessing aboveground decomposer and herbivore communities and linking their abundance and diversity to rates of decomposition and herbivory. Path analyses showed that increasing plant diversity led to higher abundance and diversity of decomposing arthropods through higher plant biomass. Higher species richness of decomposers, in turn, enhanced decomposition. Similarly, species-rich plant communities hosted a higher abundance and diversity of herbivores through elevated plant biomass and C:N ratio, leading to higher herbivory rates. Integrating trophic interactions into the study of biodiversity effects is required to understand the multiple pathways by which biodiversity affects ecosystem functioning. PMID:25226237

  5. Water produced at the University of Iowa Water treatment plant

    E-print Network

    Neiman, Maurine

    Water produced at the University of Iowa Water treatment plant meets or surpasses all federal and state drinking-water standards at this time. For information about the University of Iowa water supply, call us at 319-335-5168 Water Source The University of Iowa Water Plants' primary source of water

  6. A FULLY IMPLICIT DOMAIN DECOMPOSITION ALGORITHM FOR SHALLOW WATER EQUATIONS ON THE CUBED-SPHERE

    E-print Network

    Cai, Xiao-Chuan

    . Key words. Shallow water equations, cubed-sphere, fully implicit method, domain decomposi- tionA FULLY IMPLICIT DOMAIN DECOMPOSITION ALGORITHM FOR SHALLOW WATER EQUATIONS ON THE CUBED-SPHERE CHAO YANG, JIANWEN CAO, AND XIAO-CHUAN CAI§ Abstract. Popular approaches for solving the shallow water

  7. Rhizosphere impacts on peat decomposition and nutrient cycling across a natural water table gradient

    NASA Astrophysics Data System (ADS)

    Gill, A. L.; Finzi, A.

    2014-12-01

    High latitude forest and peatland soils represent a major terrestrial carbon store sensitive to climate change. Warming temperatures and increased growing-season evapotranspiration are projected to reduce water table (WT) height in continental peatlands. WT reduction increases peat aerobicity and facilitates vascular plant and root growth. Root-associated microbial communities are exposed to a different physical and chemical environment than microbial communities in non-root associated "bulk" peat, and therefore have distinct composition and function within the soil system. As the size of the peatland rhizosphere impacts resources available to the microbial communities, transitions from a root-free high water table peatland to a root-dominated low WT peatland may alter seasonal patterns of microbial community dynamics, enzyme production, and carbon storage within the system. We used a natural water table gradient in Caribou Bog near Orono, ME to explore the influence of species composition, root biomass, and rhizosphere size on seasonal patterns in microbial community structure, enzyme production, and carbon mineralization. We quantified root biomass across the water table gradient and measured microbial biomass carbon and nitrogen, C mineralization, N mineralization, and exoenzyme activity in root-associated and bulk peat samples throughout the 2013 growing season. Microbial biomass was consistently higher in rhizosphere-associated soils and peaked in the spring. Microbial biomass CN and enzyme activity was higher in rhizosphere-associated soil, likely due to increased mycorrhizal abundance. Exoenzyme activity peaked in the fall, with a larger relative increase in enzyme activity in rhizosphere peat, while carbon mineralization rates did not demonstrate a strong seasonal pattern. The results suggest that rhizosphere-associated peat sustains higher and more variable rates of enzyme activity throughout the growing season, which results in higher rates of carbon mineralization driven by increased microbial biomass. Increases in vascular plant abundance and root biomass may therefore increase overall rates of carbon mineralization and peat decomposition within peatland systems and influence the nature of the peatland carbon store.

  8. [Litter decomposition of dominant plant species in successional stages in mid-subtropical zone].

    PubMed

    Song, Xin-zhang; Ma, Jiang Hong; Yu, Shu-quan; Ma, Yuan-dan; Zhou, Guo-mo; Dou, Rong-peng; Guo, Pei-pei

    2009-03-01

    The litters of seven tree species representing the dominant plant species in three main successional stages in subtropical China, i.e., Pinus massoniana in early successional forests, Schima superba and Cinnamanun camphora in transitional forests, and Castanopsis eyeri, Cyclobalanopsis gracilis, Cyclobalanopsis glauca, and Michelia chapensis in late successional forests, were collected, and their decomposition rates were measured with litterbags. The results showed that M. chapensls and C. gracilis had the highest litter decomposition rate (k = 1.12 and 0.89, respectively), followed by C. camphora and S. superba (k = 0.61 and 0.55, respectively), and P. massoniana (k = 0.51), indicating that there was a trend of litter decomposition rate being increased with succession stage. Litter decomposition rate had significant correlations with the litter' s initial P, N, and lignin contents, lignin/N ratio (P < 0.01), and C/N ratio (P < 0.05), suggesting that the initial P, N, and lignin contents and lignin/N ratio of leaf litter could be the good indictors of litter decomposition rate. PMID:19637588

  9. Isotopic ((13)C) fractionation during plant residue decomposition and its implications for soil organic matter studies.

    PubMed

    Schweizer; Fear; Cadisch

    1999-07-01

    Carbon isotopic fractionations in plant materials and those occurring during decomposition have direct implications in studies of short-and longer-term soil organic matter dynamics. Thus the products of decomposition, the evolved CO(2) and the newly formed soil organic matter, may vary in their (13)C signature from that of the original plant material. To evaluate the importance of such fractionation processes, the variations in (13)C signatures between and within plant parts of a tropical grass (Brachiaria humidicola) and tropical legume (Desmodium ovalifolium) were measured and the changes in (13)C content (signatures) during decomposition were monitored over a period of four months. As expected the grass materials were less depleted in (13)C (-11.4 to -11.9 per thousand) than those of the legume (-27.3 to -25.8 per thousand). Root materials of the legume were less (1.5 per thousand) depleted in (13)C compared with the leaves. Plant lignin-C was strongly depleted in (13)C compared with the bulk material by up to 2.5 per thousand in the legume and up to 4.7 per thousand in the grass. Plant materials were subsequently incubated in a sand/nutrient-solution/microbial inoculum mixture. The respiration product CO(2) was trapped in NaOH and precipitated as CaCO(3), suitable for analysis using an automated C/N analyser coupled to an isotope ratio mass spectrometer. Significant depletion in (13)C of the evolved CO(2) was observed during the initial stages of decomposition probably as a result of microbial fractionation as it was not associated with the (13)C signatures of the measured more decomposable fractions (non-acid detergent fibre and cellulose). While the cumulative CO(2)-(13)C signatures of legume materials became slightly enriched with ongoing decomposition, the CO(2)-C of the grass materials remained depleted in (13)C. Associated isotopic fractionation correction factors for source identification of CO(2-)C varied with time and suggested errors of 2-19% in the estimation of the plant-derived C at 119 days of incubation in a soil of an intermediate (-20.0 per thousand) (13)C signature. Analysis of the residual material after 119 days of incubation showed little or no change in the (13)C signature partly due to the incomplete decomposition at the time of harvesting. Copyright 1999 John Wiley & Sons, Ltd. PMID:10407311

  10. Temperature and plant species control over litter decomposition in Alaskan tundra

    SciTech Connect

    Hobbie, S.E.

    1996-11-01

    This study compared effects of increased temperature and litter from different Alaskan tundra plant species on cycling of carbon and nitrogen through litter and soil in microcosms. Warming between 4{degrees} and 10{degrees}C significantly increased rates of soil and litter respiration, litter decomposition, litter nitrogen release, and soil net nitrogen mineralization. Thus, future warming will directly increase rates of carbon and nitrogen cycling through litter and soil in tundra. In addition, differences among species` litter in rates of decomposition, N release, and effects on soil net nitrogen mineralization were sometimes larger than differences between the two temperature treatments within a species. Thus, changes in plant community structure and composition associated with future warming will have important consequences for how elements cycle through litter and soil in tundra. In general, species within a growth form (graminoids, evergreen shrubs, deciduous shrubs, and mosses) were more similar in their effects on decomposition than were species belonging to different growth forms, with gramminoid litter having the fastest rate and litter of deciduous shrubs and mosses having the slowest rates. Differences in rates of litter decomposition were more related to carbon quality than to nitrogen concentration. Increased abundance of deciduous shrubs with future climate warming will promote carbon storage, because of their relatively large allocation to woody stems that decompose slowly. Changes in moss abundance will also have important consequences for future carbon and nitrogen cycling, since moss litter is extremely recalcitrant and has a low potential to immobilize nitrogen. 82 refs., 8 figs., 7 tabs.

  11. Differential contribution of soil biota groups to plant litter decomposition as mediated by soil use

    PubMed Central

    Falco, Liliana B.; Sandler, Rosana V.; Coviella, Carlos E.

    2015-01-01

    Plant decomposition is dependant on the activity of the soil biota and its interactions with climate, soil properties, and plant residue inputs. This work assessed the roles of different groups of the soil biota on litter decomposition, and the way they are modulated by soil use. Litterbags of different mesh sizes for the selective exclusion of soil fauna by size (macro, meso, and microfauna) were filled with standardized dried leaves and placed on the same soil under different use intensities: naturalized grasslands, recent agriculture, and intensive agriculture fields. During five months, litterbags of each mesh size were collected once a month per system with five replicates. The remaining mass was measured and decomposition rates calculated. Differences were found for the different biota groups, and they were dependant on soil use. Within systems, the results show that in the naturalized grasslands, the macrofauna had the highest contribution to decomposition. In the recent agricultural system it was the combined activity of the macro- and mesofauna, and in the intensive agricultural use it was the mesofauna activity. These results underscore the relative importance and activity of the different groups of the edaphic biota and the effects of different soil uses on soil biota activity. PMID:25780777

  12. Glucose and fructose decomposition in subcritical and supercritical water: Detailed reaction pathway, mechanisms, and kinetics

    SciTech Connect

    Kabyemela, B.M.; Adschiri, T.; Malaluan, R.M.; Arai, K.

    1999-08-01

    The authors are developing a new catalyst-free process of cellulose decomposition in supercritical water. In their initial study on the cellulose decomposition in supercritical water, the main products of cellulose decomposition were found to be oligomers of glucose (cellobiose, cellotriose, etc.) and glucose at short residence times (400 C, 25 MPa, 0.05 s). The kinetics of glucose at these conditions can be useful in understanding the reaction pathways of cellulose. Experiments were performed on the products of glucose decomposition at short residence times to elucidate the reaction pathways and evaluate kinetics of glucose and fructose decomposition in sub- and supercritical water. The conditions were a temperature of 300--400 C and pressure of 25--40 MPa for extremely short residence times between 0.02 and 2 s. The products of glucose decomposition were fructose, a product of isomerization, 1,6-anhydroglucose, a product of dehydration, and erythrose and glyceraldehyde, products of C-C bond cleavage. Fructose underwent reactions similar to glucose except that it did not form 1,6-anhydroglucose and isomerization to glucose is negligible. The mechanism for the products formed from C-C bond cleavage could be explained by reverse aldol condensation and the double-bond rule of the respective enediols formed during the Lobry de Bruyn Alberda van Ekenstein transformation. The differential equations resulting from the proposed pathways were fit to experimental results to obtain the kinetic rate constants.

  13. Hydrothermal decomposition of liquid crystal in subcritical water.

    PubMed

    Zhuang, Xuning; He, Wenzhi; Li, Guangming; Huang, Juwen; Lu, Shangming; Hou, Lianjiao

    2014-04-30

    Treatment of liquid crystal has important significance for the environment protection and human health. This study proposed a hydrothermal process to decompose the liquid crystal of 4-octoxy-4'-cyanobiphenyl. Experiments were conducted with a 5.7 mL stainless tube reactor and heated by a salt-bath. Factors affecting the decomposition rate of 4-octoxy-4'-cyanobiphenyl were evaluated with HPLC. The decomposed liquid products were characterized by GC-MS. Under optimized conditions i.e., 0.2 mL H2O2 supply, pH value 6, temperature 275°C and reaction time 5 min, 97.6% of 4-octoxy-4'-cyanobiphenyl was decomposed into simple and environment-friendly products. Based on the mechanism analysis and products characterization, a possible hydrothermal decomposition pathway was proposed. The results indicate that hydrothermal technology is a promising choice for liquid crystal treatment. PMID:24632487

  14. (Plant growth with limited water)

    SciTech Connect

    Not Available

    1991-01-01

    The work supported by DOE in the last year built on our earlier findings that stem growth in soybean subjected to limited water is inhibited first by a physical limitation followed in a few hours by metabolic changes that reduce the extensibility of the cell walls. With time, there is modest recovery in extensibility and a 28kD protein accumulates in the walls of the growth-affected cells. A 31kD protein that was 80% similar in amino acid sequence also was present but did not accumulate in the walls of the stem cells. Explorations of the mRNA for these proteins showed that the mRNA for the 28kD protein increased in the shoot in response to water deprivation but the mRNA for the 31kD protein did not accumulate. In contrast, the roots continued to grow and the mRNA for the 31kD protein accumulated but the mRNA for the 28kD protein was undetectable. We also explored how growth occurs in the absence of an external water supply. We found that, under these conditions, internal water is mobilized from surrounding nongrowing or slowly growing tissues and is used by rapidly growing cells. We showed that a low water potential is normally present in the enlarging tissues and is the likely force that extracts water from the surrounding tissues. We found that it involved a gradient in water potential that extended from the xylem to the outlying cells in the enlarging region and was not observed in the slowly growing basal tissue of the stems of the same plant. The gradient was measured directly with single cell determinations of turgor and osmotic potential in intact plants. The gradient may explain instances of growth inhibition with limited water when there is no change in the turgor of the enlarging cells. 17 refs.

  15. Photogeneration of active formate decomposition catalysts to produce hydrogen from formate and water

    DOEpatents

    King, Jr., Allen D. (Athens, GA); King, Robert B. (Athens, GA); Sailers, III, Earl L. (Athens, GA)

    1983-02-08

    A process for producing hydrogen from formate and water by photogenerating an active formate decomposition catalyst from transition metal carbonyl precursor catalysts at relatively low temperatures and otherwise mild conditions is disclosed. Additionally, this process may be expanded to include the generation of formate from carbon monoxide and hydroxide such that the result is the water gas shift reaction.

  16. Structural changes of plant residues during decomposition in a compost environment.

    PubMed

    Dresbøll, Dorte Bodin; Magid, Jakob

    2006-05-01

    The degradation of plant material during composting was investigated qualitatively by scanning electron microscopy (SEM) and quantitatively by chemical methods. Decomposition of Miscanthus (Miscanthus oogiformis L.), hemp (Cannabis sativa L.) and wheat (Triticum aestivum L.) straw was observed by placing litterbags containing these materials in compost piles. Hemp and Miscanthus straw were more stable than wheat straw, but the two materials differed in the way they were degraded despite similar chemical compositions. Hemp straw was broken down in more flexible structures compared to the rigid breakdown of Miscanthus straw. It was concluded that the anatomical arrangement of the tissue is just as important as the content of recalcitrant compounds in determining decomposition rate. Thus, when using composted plant materials as growing medium, the choice of material must depend not only on nutritional quality but also on structural quality. This study indicated that hemp material might be a good structural component in a compost to be used as a growing medium. PMID:15990291

  17. Quality assessment of plant transpiration water

    NASA Technical Reports Server (NTRS)

    Macler, Bruce A.; Janik, Daniel S.; Benson, Brian L.

    1990-01-01

    It has been proposed to use plants as elements of biologically-based life support systems for long-term space missions. Three roles have been brought forth for plants in this application: recycling of water, regeneration of air and production of food. This report discusses recycling of water and presents data from investigations of plant transpiration water quality. Aqueous nutrient solution was applied to several plant species and transpired water collected. The findings indicated that this water typically contained 0.3-6 ppm of total organic carbon, which meets hygiene water standards for NASA's space applications. It suggests that this method could be developed to achieve potable water standards.

  18. Labile Compounds in Plant Litter Reduce the Sensitivity of Decomposition to Warming and Altered Precipitation

    NASA Astrophysics Data System (ADS)

    Suseela, V.; Tharayil, N.; Xing, B.; Dukes, J. S.

    2013-12-01

    Together, climate and litter quality strongly regulate decomposition rates. While these two factors and their interaction have been studied across species in continent-scale experiments, few researchers have studied how labile and recalcitrant compounds interact to influence decomposition, or the climate sensitivity of decomposition, within a litter type. Over a period of three years, we studied the effects climate change on mass loss and compound-specific decomposition using two litter types that differed in the relative proportions of labile and recalcitrant compounds, but that had heteropolymers with similar molecular structure. We examined how warming and altered precipitation affected the decomposition of two types of Polygonum cuspidatum (Japanese knotweed) litter (stem litter that was either newly senesced or one year old), at the Boston-Area Climate Experiment (BACE), in Massachusetts, USA. We placed litter bags in an old-field ecosystem exposed to four levels of warming (up to 4oC) and three levels of precipitation (ambient, drought (-50%) and wet (+50%) treatments. The compound-specific degradation of litter was assessed using Diffuse Reflectance Infrared Fourier Transform Spectroscopy and 13C Nuclear Magnetic Resonance Spectroscopy. Climate treatments immediately affected mass loss of the more recalcitrant litter, but affected the more labile litter only after two years. After three years, although both litter types had lost similar amounts of mass, warming (~4oC) and supplemental precipitation (150% of ambient) together accelerated degradation of alkyl-carbon and lignin only in the more recalcitrant litter, highlighting the role of initial litter quality in determining whether the chemistry of litter residues converges or diverges under different climates. The results from this study indicate that the effect of climate on litter decomposition depends on the quality of litter; litter with a greater initial proportion of labile compounds was less sensitive to warming and altered precipitation. The significant effects of precipitation on mass loss and chemical composition, even in the late stages of litter decomposition, reveal the potential of climate to alter the amount and quality of carbon in plant litter available for sequestration. These results emphasize that litter chemical composition has an overriding effect on the climate sensitivity of decomposition; thus, litter quality may regulate litter-derived carbon sequestration under future climates.

  19. MINI PILOT PLANT FOR DRINKING WATER RESEARCH

    EPA Science Inventory

    The Water Supply & Water Resources Division (WSWRD) has constructed 2 mini-pilot plant systems used to conduct drinking water research. These two systems each have 2 parallel trains for comparative research. The mini-pilot plants are small conventional drinking water treatment ...

  20. Water-Conserving Plant-Growth System

    NASA Technical Reports Server (NTRS)

    Dreschel, Thomas W.; Brown, Christopher S.

    1993-01-01

    Report presents further information about plant-growth apparatus described in "Tubular Membrane Plant-Growth Unit" (KSC-11375). Apparatus provides nutrient solution to roots of seedlings without flooding. Conserves water by helping to prevent evaporation from plant bed. Solution supplied only as utilized by seedlings. Device developed for supporting plant growth in space, also has applications for growing plants with minimum of water, such as in arid environments.

  1. Kinetics of glucose epimerization and decomposition in subcritical and supercritical water

    SciTech Connect

    Kabyemela, B.M.; Adschiri, Tadafumi; Malaluan, R.M.; Arai, Kunio

    1997-05-01

    Glucose decomposition kinetics in subcritical and supercritical water were studied for the temperatures 573, 623, and 673 K, pressures between 25 and 40 MPa, and residence times between 0.02 and 2 s. Glucose decomposition products were fructose, saccharinic acids, erythrose, glyceraldehyde, 1,6-anhydroglucose, dihydroxyacetone, pyruvaldehyde, and small amounts of 5-hydroxymethylfurfural. Fructose was also studied and found to decompose to products similar to those of glucose, except that its epimerization to glucose was negligibly low and no formation of 1,6-anhydroglucose was detected. The authors concluded that only the forward epimerization of glucose to fructose was important. The glucose decomposition pathway could be described in terms of a forward epimerization rate, r{sub gf}, a fructose to decomposition products rate, r{sub f}, and a glucose to decomposition products rate, r{sub g}. A kinetic model based on this pathway gave good correlation of the experimental data. In the subcritical region, r{sub g}, r{sub f}, and r{sub gf} showed only small changes with pressure at a given temperature. In the supercritical region, the rate of glucose decomposition decreased with pressure at a given temperature. The reason for this decrease was mainly due to the decrease in r{sub gf}. The pressure effect in the supercritical region shows that there is a shift among the kinetic rates, which can lead to higher selectivity for glucose when decomposing cellulosic materials.

  2. Reconciling Phylogeny and Function During Plant Litter Decomposition by High-Throughput Functional Metagenomics

    NASA Astrophysics Data System (ADS)

    Nyyssonen, M.; Weihe, C.; Goulden, M.; Treseder, K. K.; Martiny, J.; Martiny, A.; Allison, S. D.; Brodie, E. L.

    2012-12-01

    Integrating information on microbial diversity and functionality with ecosystem processes may be critical to predicting how ecosystems respond to environmental change. While theoretical models can be used to link microbial processes to environmental responses and rates, accurate predictions of ecosystem functioning would benefit from detailed information on microbial community composition and function. In this study, our aim was to identify functional traits involved in plant litter decomposition, a model process for carbon cycling, from decomposing plant litter. The overall goal is then to link these traits with individual microbial taxa and use this information to build predictive trait-based models of ecosystem responses to global change. In order to identify activities involved in plant litter decomposition we used automated high-throughput assays for functional screening of metagenomic fosmid libraries prepared from decomposing plant litter. Litter was collected over 15 month period from a global change field experiment undergoing rainfall and nitrogen manipulations. We identified over 600 cellulose, hemicellulose, chitin and starch hydrolyzing clones following screening of over 300,000 clones. The frequency of positive clones was ten times lower during dry season but no significant differences in hit rates were observed between different treatments. The positive clones were shotgun sequenced on the Illumina sequencing platform and the identified hydrolytic genes were shown to represent variety bacterial taxonomic groups including Proteobacteria and Bacteroidetes.

  3. Effects of electron acceptors on soluble reactive phosphorus in the overlying water during algal decomposition.

    PubMed

    Wang, Jinzhi; Jiang, Xia; Zheng, Binghui; Niu, Yuan; Wang, Kun; Wang, Wenwen; Kardol, Paul

    2015-12-01

    Endogenous phosphorus (P) release from sediments is an important factor to cause eutrophication and, hence, algal bloom in lakes in China. Algal decomposition depletes dissolved oxygen (DO) and causes anaerobic conditions and therefore increases P release from sediments. As sediment P release is dependent on the iron (Fe) cycle, electron acceptors (e.g., NO3 (-), SO4 (2-), and Mn(4+)) can be utilized to suppress the reduction of Fe(3+) under anaerobic conditions and, as such, have the potential to impair the release of sediment P. Here, we used a laboratory experiment to test the effects of FeCl3, MnO2, and KNO3 on soluble reactive phosphorus (SRP) concentration and related chemical variables in the overlying water column during algal decomposition at different algal densities. Results showed that algal decomposition significantly depleted DO and thereby increased sediment Fe-bound P release. Compared with the control, addition of FeCl3 significantly decreased water SRP concentration through inhibiting sediment P release. Compared with FeCl3, addition of MnO2 has less potential to suppress sediment P release during algal decomposition. Algal decomposition has the potential for NO3 (-) removal from aquatic ecosystem through denitrification and by that alleviates the suppressing role of NO3 (-) on sediment P release. Our results indicated that FeCl3 and MnO2 could be efficient in reducing sediment P release during algal decomposition, with the strongest effect found for FeCl3; large amounts of NO3 (-) were removed from the aquatic ecosystem through denitrification during algal decomposition. Moreover, the amounts of NO3 (-) removal increased with increasing algal density. PMID:26263882

  4. Plant Species Rather Than Climate Greatly Alters the Temporal Pattern of Litter Chemical Composition During Long-Term Decomposition

    NASA Astrophysics Data System (ADS)

    Li, Yongfu; Chen, Na; Harmon, Mark E.; Li, Yuan; Cao, Xiaoyan; Chappell, Mark A.; Mao, Jingdong

    2015-10-01

    A feedback between decomposition and litter chemical composition occurs with decomposition altering composition that in turn influences the decomposition rate. Elucidating the temporal pattern of chemical composition is vital to understand this feedback, but the effects of plant species and climate on chemical changes remain poorly understood, especially over multiple years. In a 10-year decomposition experiment with litter of four species (Acer saccharum, Drypetes glauca, Pinus resinosa, and Thuja plicata) from four sites that range from the arctic to tropics, we determined the abundance of 11?litter chemical constituents that were grouped into waxes, carbohydrates, lignin/tannins, and proteins/peptides using advanced 13C solid-state NMR techniques. Decomposition generally led to an enrichment of waxes and a depletion of carbohydrates, whereas the changes of other chemical constituents were inconsistent. Inconsistent convergence in chemical compositions during decomposition was observed among different litter species across a range of site conditions, whereas one litter species converged under different climate conditions. Our data clearly demonstrate that plant species rather than climate greatly alters the temporal pattern of litter chemical composition, suggesting the decomposition-chemistry feedback varies among different plant species.

  5. Plant Species Rather Than Climate Greatly Alters the Temporal Pattern of Litter Chemical Composition During Long-Term Decomposition

    PubMed Central

    Li, Yongfu; Chen, Na; Harmon, Mark E.; Li, Yuan; Cao, Xiaoyan; Chappell, Mark A.; Mao, Jingdong

    2015-01-01

    A feedback between decomposition and litter chemical composition occurs with decomposition altering composition that in turn influences the decomposition rate. Elucidating the temporal pattern of chemical composition is vital to understand this feedback, but the effects of plant species and climate on chemical changes remain poorly understood, especially over multiple years. In a 10-year decomposition experiment with litter of four species (Acer saccharum, Drypetes glauca, Pinus resinosa, and Thuja plicata) from four sites that range from the arctic to tropics, we determined the abundance of 11?litter chemical constituents that were grouped into waxes, carbohydrates, lignin/tannins, and proteins/peptides using advanced 13C solid-state NMR techniques. Decomposition generally led to an enrichment of waxes and a depletion of carbohydrates, whereas the changes of other chemical constituents were inconsistent. Inconsistent convergence in chemical compositions during decomposition was observed among different litter species across a range of site conditions, whereas one litter species converged under different climate conditions. Our data clearly demonstrate that plant species rather than climate greatly alters the temporal pattern of litter chemical composition, suggesting the decomposition-chemistry feedback varies among different plant species. PMID:26515033

  6. Plant Species Rather Than Climate Greatly Alters the Temporal Pattern of Litter Chemical Composition During Long-Term Decomposition.

    PubMed

    Li, Yongfu; Chen, Na; Harmon, Mark E; Li, Yuan; Cao, Xiaoyan; Chappell, Mark A; Mao, Jingdong

    2015-01-01

    A feedback between decomposition and litter chemical composition occurs with decomposition altering composition that in turn influences the decomposition rate. Elucidating the temporal pattern of chemical composition is vital to understand this feedback, but the effects of plant species and climate on chemical changes remain poorly understood, especially over multiple years. In a 10-year decomposition experiment with litter of four species (Acer saccharum, Drypetes glauca, Pinus resinosa, and Thuja plicata) from four sites that range from the arctic to tropics, we determined the abundance of 11?litter chemical constituents that were grouped into waxes, carbohydrates, lignin/tannins, and proteins/peptides using advanced (13)C solid-state NMR techniques. Decomposition generally led to an enrichment of waxes and a depletion of carbohydrates, whereas the changes of other chemical constituents were inconsistent. Inconsistent convergence in chemical compositions during decomposition was observed among different litter species across a range of site conditions, whereas one litter species converged under different climate conditions. Our data clearly demonstrate that plant species rather than climate greatly alters the temporal pattern of litter chemical composition, suggesting the decomposition-chemistry feedback varies among different plant species. PMID:26515033

  7. Thermochemical water decomposition. [hydrogen separation for energy applications

    NASA Technical Reports Server (NTRS)

    Funk, J. E.

    1977-01-01

    At present, nearly all of the hydrogen consumed in the world is produced by reacting hydrocarbons with water. As the supply of hydrocarbons diminishes, the problem of producing hydrogen from water alone will become increasingly important. Furthermore, producing hydrogen from water is a means of energy conversion by which thermal energy from a primary source, such as solar or nuclear fusion of fission, can be changed into an easily transportable and ecologically acceptable fuel. The attraction of thermochemical processes is that they offer the potential for converting thermal energy to hydrogen more efficiently than by water electrolysis. A thermochemical hydrogen-production process is one which requires only water as material input and mainly thermal energy, or heat, as an energy input. Attention is given to a definition of process thermal efficiency, the thermodynamics of the overall process, the single-stage process, the two-stage process, multistage processes, the work of separation and a process evaluation.

  8. DRINKING WATER TREATMENT PLANT ADVISOR - USER DOCUMENTATION

    EPA Science Inventory

    The Drinking Water Treatment Plant (DWTP) Advisor is a software application which has been designed to provide assistance in the evaluation of drinking water treatment plants. Specifically, this program, which is based on the source document Interim Handbook Optimizing Water Trea...

  9. Response of plants to water stress

    PubMed Central

    Osakabe, Yuriko; Osakabe, Keishi; Shinozaki, Kazuo; Tran, Lam-Son P.

    2014-01-01

    Water stress adversely impacts many aspects of the physiology of plants, especially photosynthetic capacity. If the stress is prolonged, plant growth, and productivity are severely diminished. Plants have evolved complex physiological and biochemical adaptations to adjust and adapt to a variety of environmental stresses. The molecular and physiological mechanisms associated with water-stress tolerance and water-use efficiency have been extensively studied. The systems that regulate plant adaptation to water stress through a sophisticated regulatory network are the subject of the current review. Molecular mechanisms that plants use to increase stress tolerance, maintain appropriate hormone homeostasis and responses and prevent excess light damage, are also discussed. An understanding of how these systems are regulated and ameliorate the impact of water stress on plant productivity will provide the information needed to improve plant stress tolerance using biotechnology, while maintaining the yield and quality of crops. PMID:24659993

  10. Complementary symbiont contributions to plant decomposition in a fungus-farming termite

    PubMed Central

    Hu, Haofu; Li, Cai; Chen, Zhensheng; Otani, Saria; Nygaard, Sanne; Nobre, Tania; Klaubauf, Sylvia; Schindler, Philipp M.; Hauser, Frank; Pan, Hailin; Yang, Zhikai; Sonnenberg, Anton S. M.; de Beer, Z. Wilhelm; Zhang, Yong; Wingfield, Michael J.; Grimmelikhuijzen, Cornelis J. P.; de Vries, Ronald P.; Korb, Judith; Aanen, Duur K.; Wang, Jun; Boomsma, Jacobus J.; Zhang, Guojie

    2014-01-01

    Termites normally rely on gut symbionts to decompose organic matter but the Macrotermitinae domesticated Termitomyces fungi to produce their own food. This transition was accompanied by a shift in the composition of the gut microbiota, but the complementary roles of these bacteria in the symbiosis have remained enigmatic. We obtained high-quality annotated draft genomes of the termite Macrotermes natalensis, its Termitomyces symbiont, and gut metagenomes from workers, soldiers, and a queen. We show that members from 111 of the 128 known glycoside hydrolase families are represented in the symbiosis, that Termitomyces has the genomic capacity to handle complex carbohydrates, and that worker gut microbes primarily contribute enzymes for final digestion of oligosaccharides. This apparent division of labor is consistent with the Macrotermes gut microbes being most important during the second passage of comb material through the termite gut, after a first gut passage where the crude plant substrate is inoculated with Termitomyces asexual spores so that initial fungal growth and polysaccharide decomposition can proceed with high efficiency. Complex conversion of biomass in termite mounds thus appears to be mainly accomplished by complementary cooperation between a domesticated fungal monoculture and a specialized bacterial community. In sharp contrast, the gut microbiota of the queen had highly reduced plant decomposition potential, suggesting that mature reproductives digest fungal material provided by workers rather than plant substrate. PMID:25246537

  11. Complementary symbiont contributions to plant decomposition in a fungus-farming termite.

    PubMed

    Poulsen, Michael; Hu, Haofu; Li, Cai; Chen, Zhensheng; Xu, Luohao; Otani, Saria; Nygaard, Sanne; Nobre, Tania; Klaubauf, Sylvia; Schindler, Philipp M; Hauser, Frank; Pan, Hailin; Yang, Zhikai; Sonnenberg, Anton S M; de Beer, Z Wilhelm; Zhang, Yong; Wingfield, Michael J; Grimmelikhuijzen, Cornelis J P; de Vries, Ronald P; Korb, Judith; Aanen, Duur K; Wang, Jun; Boomsma, Jacobus J; Zhang, Guojie

    2014-10-01

    Termites normally rely on gut symbionts to decompose organic matter but the Macrotermitinae domesticated Termitomyces fungi to produce their own food. This transition was accompanied by a shift in the composition of the gut microbiota, but the complementary roles of these bacteria in the symbiosis have remained enigmatic. We obtained high-quality annotated draft genomes of the termite Macrotermes natalensis, its Termitomyces symbiont, and gut metagenomes from workers, soldiers, and a queen. We show that members from 111 of the 128 known glycoside hydrolase families are represented in the symbiosis, that Termitomyces has the genomic capacity to handle complex carbohydrates, and that worker gut microbes primarily contribute enzymes for final digestion of oligosaccharides. This apparent division of labor is consistent with the Macrotermes gut microbes being most important during the second passage of comb material through the termite gut, after a first gut passage where the crude plant substrate is inoculated with Termitomyces asexual spores so that initial fungal growth and polysaccharide decomposition can proceed with high efficiency. Complex conversion of biomass in termite mounds thus appears to be mainly accomplished by complementary cooperation between a domesticated fungal monoculture and a specialized bacterial community. In sharp contrast, the gut microbiota of the queen had highly reduced plant decomposition potential, suggesting that mature reproductives digest fungal material provided by workers rather than plant substrate. PMID:25246537

  12. Daily water level forecasting using wavelet decomposition and artificial intelligence techniques

    NASA Astrophysics Data System (ADS)

    Seo, Youngmin; Kim, Sungwon; Kisi, Ozgur; Singh, Vijay P.

    2015-01-01

    Reliable water level forecasting for reservoir inflow is essential for reservoir operation. The objective of this paper is to develop and apply two hybrid models for daily water level forecasting and investigate their accuracy. These two hybrid models are wavelet-based artificial neural network (WANN) and wavelet-based adaptive neuro-fuzzy inference system (WANFIS). Wavelet decomposition is employed to decompose an input time series into approximation and detail components. The decomposed time series are used as inputs to artificial neural networks (ANN) and adaptive neuro-fuzzy inference system (ANFIS) for WANN and WANFIS models, respectively. Based on statistical performance indexes, the WANN and WANFIS models are found to produce better efficiency than the ANN and ANFIS models. WANFIS7-sym10 yields the best performance among all other models. It is found that wavelet decomposition improves the accuracy of ANN and ANFIS. This study evaluates the accuracy of the WANN and WANFIS models for different mother wavelets, including Daubechies, Symmlet and Coiflet wavelets. It is found that the model performance is dependent on input sets and mother wavelets, and the wavelet decomposition using mother wavelet, db10, can further improve the efficiency of ANN and ANFIS models. Results obtained from this study indicate that the conjunction of wavelet decomposition and artificial intelligence models can be a useful tool for accurate forecasting daily water level and can yield better efficiency than the conventional forecasting models.

  13. Carbon availability triggers the decomposition of plant litter and assimilation of nitrogen by an ectomycorrhizal fungus

    PubMed Central

    Rineau, F; Shah, F; Smits, M M; Persson, P; Johansson, T; Carleer, R; Troein, C; Tunlid, A

    2013-01-01

    The majority of nitrogen in forest soils is found in organic matter–protein complexes. Ectomycorrhizal fungi (EMF) are thought to have a key role in decomposing and mobilizing nitrogen from such complexes. However, little is known about the mechanisms governing these processes, how they are regulated by the carbon in the host plant and the availability of more easily available forms of nitrogen sources. Here we used spectroscopic analyses and transcriptome profiling to examine how the presence or absence of glucose and/or ammonium regulates decomposition of litter material and nitrogen mobilization by the ectomycorrhizal fungus Paxillus involutus. We found that the assimilation of nitrogen and the decomposition of the litter material are triggered by the addition of glucose. Glucose addition also resulted in upregulation of the expression of genes encoding enzymes involved in oxidative degradation of polysaccharides and polyphenols, peptidases, nitrogen transporters and enzymes in pathways of the nitrogen and carbon metabolism. In contrast, the addition of ammonium to organic matter had relatively minor effects on the expression of transcripts and the decomposition of litter material, occurring only when glucose was present. On the basis of spectroscopic analyses, three major types of chemical modifications of the litter material were observed, each correlated with the expression of specific sets of genes encoding extracellular enzymes. Our data suggest that the expression of the decomposition and nitrogen assimilation processes of EMF can be tightly regulated by the host carbon supply and that the availability of inorganic nitrogen as such has limited effects on saprotrophic activities. PMID:23788332

  14. Radiolytic decomposition of multi-class surfactants and their biotransformation products in sewage treatment plant effluents.

    PubMed

    Petrovic, M; Gehringer, P; Eschweiler, H; Barceló, D

    2007-01-01

    Electron beam irradiation (EBI), as one of the most efficient advanced oxidation processes, was applied to the treatment of sewage treatment plant (STP) effluent, with the objective of evaluating the effectiveness of radiolytic decomposition of multi-class surfactants. Target compounds, included several high-volume surfactant groups, such as alkylphenol ethoxylates (APEOs) and their biotransformation products, linear alkylbenzene sulfonates (LAS), alkyl sulfates (AS), alkylether sulfates (AES), coconut diethanol amides (CDEA), alcohol ethoxylates (AEO) and polyethylene glycols (PEGs). EBI treatment of STP effluent (total concentration of APEO-derived compounds 265mugl(-1), being APE(2)C the most abundant by-degradation products) resulted in efficient decomposition of all alkylphenolic compounds; elimination of 94% longer ethoxy chain nonylphenol ethoxylates (NPEO, n(EO)=3-15) was obtained when 3kGy were applied. Slightly less efficient decomposition of short ethoxy chain oligomers (NPEO(1) and NPEO(2)) was observed, resulting in disappearance of about 80% of the initially present compounds. LC-MS analysis of treated wastewater suggested that the mechanism of EBI degradation of APEOs is a combination of two parallel pathways: a progressive shortening and oxidation of the ethoxy chain, which resulted in a formation of short ethoxy chain oligomers and APECs and central fission that resulted in formation of PEGs. Decomposition of APECs at 1kGy initially yielded APs, which were subsequently eliminated applying higher radiation doses. With a radiation dose of 2kGy about 95% of NPE(1)C and 97% of NPE(2)C were decomposed. Similar elimination rates were obtained for octylphenolic compounds. Radiolytic treatment applied was also very effective in removing PEGs formed as by-products from APEO degradation, as well as in decomposing other surfactants, such as linear LAS, AS and AES. PMID:16808959

  15. Photocatalytic Decomposition of Water: Next Generation Fuel Source

    NASA Astrophysics Data System (ADS)

    Hanks, Keegan

    2010-10-01

    Photocatalysis of hydrogen from water has been vastly concerned with using a Pt/Ru co-catalyst for the generation of hydrogen from water and molecular co-catalysts with hydrocarbon precursors. This process contains separate nucleation sites and proves to have a limited efficency. Molecular and nanoparticle co-catalysts have also been considered showing an improvement in the applicability of this water-splitting process to produce a clean and renewable fuel from a simple and green reaction process. Recent research has vastly improved the feasibility of the nanoparticle co-catalyst based process as a clean and reliable resource for fuel. I present herein a theoretical application of composite nanoparticles using transition metal semiconductors. I propose the composite nanostructures as the catalylst and the co-catalyst in one nanoparticle rather than an expensive Pt co-catalyst and molecular catalyst combo. With this approach, our goal is to develop a single beaker synthesis of these nanoparticles and place them in water under artificial sunlight in our newly developed laboratories here on campus to characterize the nanoparticles and analyze the efficency of hydrogen generation.

  16. Decomposition of Fresh and Anaerobically Digested Plant Biomass in Soil1 K. K. MOORHEAD, D. A, GRAETZ, AND K. R. REDDY2

    E-print Network

    Florida, University of

    Decomposition of Fresh and Anaerobically Digested Plant Biomass in Soil1 K. K. MOORHEAD, D. A for soil are often determined by nutrient-release potential dur- ing decomposition. The N decomposition of anaerobically digested sewage sludge (Miller, 1974; Tester et al., 1977). Much of the available

  17. The generation of hydrogen by the thermal decomposition of water

    NASA Technical Reports Server (NTRS)

    Funk, J. E.

    1974-01-01

    Development of an approach to the evaluation of the thermal efficiency of the process of water splitting to produce hydrogen. A way of viewing thermochemical processes - both overall and step-by-step is suggested, and some recent work on a process evaluation technique is described which provides internal checks on the thermodynamic data and calculates, in addition to the efficiency, many important process parameters.

  18. Water protection in coke-plant design

    SciTech Connect

    G.I. Alekseev

    2009-07-15

    Wastewater generation, water consumption, and water management at coke plants are considered. Measures to create runoff-free water-supply and sewer systems are discussed. Filters for water purification, corrosion inhibitors, and biocides are described. An integrated single-phase technology for the removal of phenols, thiocyanides, and ammoniacal nitrogen is outlined.

  19. Decomposition of Phragmites australis rhizomes in artificial land-water transitional zones (ALWTZs) and management implications

    NASA Astrophysics Data System (ADS)

    Han, Zhen; Cui, Baoshan; Zhang, Yongtao

    2015-09-01

    Rhizomes are essential organs for growth and expansion of Phragmites australis. They function as an important source of organic matter and as a nutrient source, especially in the artificial land-water transitional zones (ALWTZs) of shallow lakes. In this study, decomposition experiments on 1- to 6-year-old P. australis rhizomes were conducted in the ALWTZ of Lake Baiyangdian to evaluate the contribution of the rhizomes to organic matter accumulation and nutrient release. Mass loss and changes in nutrient content were measured after 3, 7, 15, 30, 60, 90, 120, and 180 days. The decomposition process was modeled with a composite exponential model. The Pearson correlation analysis was used to analyze the relationships between mass loss and litter quality factors. A multiple stepwise regression model was utilized to determine the dominant factors that affect mass loss. Results showed that the decomposition rates in water were significantly higher than those in soil for 1- to 6-year-old rhizomes. However, the sequence of decomposition rates was identical in both water and soil. Significant relationships between mass loss and litter quality factors were observed at a later stage, and P-related factors proved to have a more significant impact than N-related factors on mass loss. According to multiple stepwise models, the C/P ratio was found to be the dominant factor affecting the mass loss in water, and the C/N and C/P ratios were the main factors affecting the mass loss in soil. The combined effects of harvesting, ditch broadening, and control of water depth should be considered for lake administrators.

  20. Regulation of Water in Plant Cells

    ERIC Educational Resources Information Center

    Kowles, Richard V.

    2010-01-01

    Cell water relationships are important topics to be included in cell biology courses. Differences exist in the control of water relationships in plant cells relative to control in animal cells. One important reason for these differences is that turgor pressure is a consideration in plant cells. Diffusion and osmosis are the underlying factors…

  1. Method of generating hydrogen by catalytic decomposition of water

    DOEpatents

    Balachandran, Uthamalingam (Hinsdale, IL); Dorris, Stephen E. (LaGrange Park, IL); Bose, Arun C. (Pittsburgh, PA); Stiegel, Gary J. (Library, PA); Lee, Tae-Hyun (Naperville, IL)

    2002-01-01

    A method for producing hydrogen includes providing a feed stream comprising water; contacting at least one proton conducting membrane adapted to interact with the feed stream; splitting the water into hydrogen and oxygen at a predetermined temperature; and separating the hydrogen from the oxygen. Preferably the proton conducting membrane comprises a proton conductor and a second phase material. Preferable proton conductors suitable for use in a proton conducting membrane include a lanthanide element, a Group VIA element and a Group IA or Group IIA element such as barium, strontium, or combinations of these elements. More preferred proton conductors include yttrium. Preferable second phase materials include platinum, palladium, nickel, cobalt, chromium, manganese, vanadium, silver, gold, copper, rhodium, ruthenium, niobium, zirconium, tantalum, and combinations of these. More preferably second phase materials suitable for use in a proton conducting membrane include nickel, palladium, and combinations of these. The method for generating hydrogen is preferably preformed in the range between about 600.degree. C. and 1,700.degree. C.

  2. Accelerating the degradation of green plant waste with chemical decomposition agents.

    PubMed

    Kejun, Sun; Juntao, Zhang; Ying, Chen; Zongwen, Liao; Lin, Ruan; Cong, Liu

    2011-10-01

    Degradation of green plant waste is often difficult, and excess maturity times are typically required. In this study, we used lignin, cellulose and hemicellulose assays; scanning electron microscopy; infrared spectrum analysis and X-ray diffraction analysis to investigate the effects of chemical decomposition agents on the lignocellulose content of green plant waste, its structure and major functional groups and the mechanism of accelerated degradation. Our results showed that adding chemical decomposition agents to Ficus microcarpa var. pusillifolia sawdust reduced the contents of lignin by 0.53%-11.48% and the contents of cellulose by 2.86%-7.71%, and increased the contents of hemicellulose by 2.92%-33.63% after 24 h. With increasing quantities of alkaline residue and sodium lignosulphonate, the lignin content decreased. Scanning electron microscopy showed that, after F. microcarpa var. pusillifolia sawdust was treated with chemical decomposition agents, lignocellulose tube wall thickness increased significantlyIncreases of 29.41%, 3.53% and 34.71% were observed after treatment with NaOH, alkaline residue and sodium lignosulphonate, respectively. Infrared spectroscopy showed that CO and aromatic skeleton stretching absorption peaks were weakened and the C-H vibrational absorption peak from out-of-plane in positions 2 and 6 (S units) (890-900 cm(-1)) was strengthened after F. microcarpa var. pusillifolia sawdust was treated with chemical decomposition agents, indicating a reduction in lignin content. Several absorption peaks [i.e., C-H deformations (asymmetry in methyl groups, -CH(3)- and -CH(2)-) (1450-1460 cm(-1)); Aliphatic C-H stretching in methyl and phenol OH (1370-1380 cm(-1)); CO stretching (cellulose and hemicellulose) (1040-1060 cm(-1))] that indicate the presence of a chemical bond between lignin and cellulose was reduced, indicating that the chemical bond between lignin and cellulose had been partially broken. X-ray diffraction analysis showed that NaOH, alkaline residue and sodium lignosulphonate can reduce the relative crystallinity of lignocellulose in F. microcarpa var. pusillifolia by 2.64%, 13.24%, 12.44%, respectively. The C-H vibrational absorption peak from out-of-plane in positions 2 and 6 (S units) comes from the vibration of the sugar anomeric carbon. Because lignin is a phenolic, not carbohydrate polymer, the relative absorption intensity of this peak should be stronger at lower lignin contents. Compared to CK, the peak intensities increased in treatments T1, T5 and T9, indicating reduced lignin contents and increased sugar contents after CDA treatment. PMID:21763065

  3. Plant inter-species effects on rhizosphere priming of soil organic matter decomposition

    NASA Astrophysics Data System (ADS)

    Pausch, Johanna; Zhu, Biao; Cheng, Weixin

    2015-04-01

    Living roots and their rhizodeposits can stimulate microbial activity and soil organic matter (SOM) decomposition up to several folds. This so-called rhizosphere priming effect (RPE) varies widely among plant species possibly due to species-specific differences in the quality and quantity of rhizodeposits and other root functions. However, whether the RPE is influenced by plant inter-species interactions remains largely unexplored, even though these interactions can fundamentally shape plant functions such as carbon allocation and nutrient uptake. In a 60-day greenhouse experiment, we continuously labeled monocultures and mixtures of sunflower, soybean and wheat with 13C-depleted CO2 and partitioned total CO2 efflux released from soil at two stages of plant development for SOM- and root-derived CO2. The RPE was calculated as the difference in SOM-derived CO2 between the planted and the unplanted soil, and was compared among the monocultures and mixtures. We found that the RPE was positive under all plants, ranging from 43% to 136% increase above the unplanted control. There were no significant differences in RPE at the vegetative stage. At the flowering stage however, the RPE in the soybean-wheat mixture was significantly higher than those in the sunflower monoculture, the sunflower-wheat mixture, and the sunflower-soybean mixture. These results indicated that the influence of plant inter-specific interactions on the RPE is case-specific and phenology-dependent. To evaluate the intensity of inter-specific effects on priming, we calculated an expected RPE for the mixtures based on the RPE of the monocultures weighted by their root biomass and compared it to the measured RPE under mixtures. At flowering, the measured RPE was significantly lower for the sunflower-wheat mixture than what can be expected from their monocultures, suggesting that RPE was significantly reduced by the inter-species effects of sunflower and wheat. In summary, our results clearly demonstrated that inter-species interactions can significantly modify rhizosphere priming on SOM decomposition.

  4. Species and tissue type regulate long-term decomposition of brackish marsh plants grown under elevated CO2 conditions

    USGS Publications Warehouse

    Jones, Joshua A; Cherry, Julia A; Mckee, Karen L.

    2016-01-01

    Organic matter accumulation, the net effect of plant production and decomposition, contributes to vertical soil accretion in coastal wetlands, thereby playing a key role in whether they keep pace with sea-level rise. Any factor that affects decomposition may affect wetland accretion, including atmospheric CO2 concentrations. Higher CO2 can influence decomposition rates by altering plant tissue chemistry or by causing shifts in plant species composition or biomass partitioning. A combined greenhouse-field experiment examined how elevated CO2 affected plant tissue chemistry and subsequent decomposition of above- and belowground tissues of two common brackish marsh species, Schoenoplectus americanus (C3) and Spartina patens (C4). Both species were grown in monoculture and in mixture under ambient (350-385 ?L L-1) or elevated (ambient + 300 ?L L-1) atmospheric CO2 conditions, with all other growth conditions held constant, for one growing season. Above- and belowground tissues produced under these treatments were decomposed under ambient field conditions in a brackish marsh in the Mississippi River Delta, USA. Elevated CO2 significantly reduced nitrogen content of S. americanus, but not sufficiently to affect subsequent decomposition. Instead, long-term decomposition (percent mass remaining after 280 d) was controlled by species composition and tissue type. Shoots of S. patens had more mass remaining (41 ± 2%) than those of S. americanus (12 ± 2 %). Belowground material decomposed more slowly than that placed aboveground (62 ± 1% vs. 23 ± 3% mass remaining), but rates belowground did not differ between species. Increases in atmospheric CO2concentration will likely have a greater effect on overall decomposition in this brackish marsh community through shifts in species dominance or biomass allocation than through effects on tissue chemistry. Consequent changes in organic matter accumulation may alter marsh capacity to accommodate sea-level rise through vertical accretion.

  5. Photoassisted decomposition of water over doped rutile electrodes

    NASA Astrophysics Data System (ADS)

    Giordano, N.; Antonucci, V.; Cavallaro, S.; Lembo, R.; Bart, J. C. J.

    The photoelectrolysis of water on a series of doped TiO2 semiconductors is presented. The TiO2 electrodes are prepared from 1 mm thick laminae of titanium, oxidized in an oven at 700 C for 4 h, and repeatedly impregnated in aqueous or acid (HCL) solutions containing equimolar (1M) quantities of TiCl3 and nitrates (or chlorides) of the dopant metal. The electrode current-voltage characteristics are measured in a one-compartment cell, using a 1 m Na 2SO4 solution. A 400 W medium pressure mercury lamp, emitting in the 310 to 1000 nm range, is used as a light source. Cell potentials are measured with an electrometer. An expression is derived for the energy conversion efficiency, which is strongly influenced by the preparation procedure. Pt-doping has the most marked positive influence and results in an energy conversion of 2.8 percent at 1 sun concentration, vs. 0.5 percent for an undoped sample. It is suggested that the best dopants, such as Pt, act through a reduction of the surface, thereby decreasing its acidity and increasing n-typeness.

  6. Combining experiment and theory to elucidate the role of supercritical water in sulfide decomposition.

    PubMed

    Kida, Yuko; Class, Caleb A; Concepcion, Anthony J; Timko, Michael T; Green, William H

    2014-05-28

    The cleavage of C-S linkages plays a key role in fuel processing and organic geochemistry. Water is known to affect these processes, and several hypotheses have been proposed, but the mechanism has been elusive. Here we use both experiment and theory to demonstrate that supercritical water reacts with intermediates formed during alkyl sulfide decomposition. During hexyl sulfide decomposition in supercritical water, pentane and CO + CO2 were detected in addition to the expected six carbon products. A multi-step reaction sequence for hexyl sulfide reacting with supercritical water is proposed which explains the surprising products, and quantum chemical calculations provide quantitative rates that support the proposed mechanism. The key sequence is cleavage of one C-S bond to form a thioaldehyde via radical reactions, followed by a pericyclic addition of water to the C[double bond, length as m-dash]S bond to form a geminal mercaptoalcohol. The mercaptoalcohol decomposes into an aldehyde and H2S either directly or via a water-catalyzed 6-membered ring transition state. The aldehyde quickly decomposes into CO plus pentane by radical reactions. The time is ripe for quantitative modelling of organosulfur reaction kinetics based on modern quantum chemistry. PMID:24728624

  7. A Trip to the Water Plant.

    ERIC Educational Resources Information Center

    Laskey, Marilyn

    Produced for primary and intermediate grades, this student booklet provides a study of where water comes from, how we get clean water, and the operations of a water treatment plant. Photographs, a few line drawings, a minimum of narrative, and a glossary of terms make up its content. A related document is the teacher's guide, SE 016 490. This work…

  8. Fat water decomposition using GlObally Optimal Surface Estimation (GOOSE) algorithm

    PubMed Central

    Cui, Chen; Wu, Xiaodong; Newell, John D; Jacob, Mathews

    2015-01-01

    Purpose This paper focuses on developing a novel non-iterative fat water decomposition algorithm more robust to fat water swaps and related ambiguities. Methods Field map estimation is reformulated as a constrained surface estimation problem to exploit the spatial smoothness of the field, thus minimizing the ambiguities in the recovery. Specifically, the differences in the field map induced frequency shift between adjacent voxels are constrained to be in a finite range. The discretization of the above problem yields a graph optimization scheme, where each node of the graph is only connected with few other nodes. Thanks to the low graph connectivity, the problem is solved efficiently using a non-iterative graph cut algorithm. The global minimum of the constrained optimization problem is guaranteed. The performance of the algorithm is compared with that of state-of-the-art schemes. Quantitative comparisons are also made against reference data. Results The proposed algorithm is observed to yield more robust fat water estimates with fewer fat water swaps and better quantitative results than other state-of-the-art algorithms in a range of challenging applications. Conclusion The proposed algorithm is capable of considerably reducing the swaps in challenging fat water decomposition problems. The experiments demonstrate the benefit of using explicit smoothness constraints in field map estimation and solving the problem using a globally convergent graph-cut optimization algorithm. PMID:24604689

  9. Aquatic Plant Water Quality Criteria

    EPA Science Inventory

    The USEPA, as stated in the Clean Water Act, is tasked with developing numerical Aquatic Life Critiera for various pollutants found in the waters of the United States. These criteria serve as guidance for States and Tribes to use in developing their water quality standards. The G...

  10. Water/Wastewater Treatment Plant Operator Qualifications.

    ERIC Educational Resources Information Center

    Water and Sewage Works, 1979

    1979-01-01

    This article summarizes in tabular form the U.S. and Canadian programs for classification of water and wastewater treatment plant personnel. Included are main characteristics of the programs, educational and experience requirements, and indications of requirement substitutions. (CS)

  11. Drinking Water Plant Lecture-Demonstration.

    ERIC Educational Resources Information Center

    Vestling, Martha M.

    1977-01-01

    Describes a simple way to demonstrate the principles involved in a drinking water plant. This demonstration developed for a general public lecture can be used in chemistry and biology courses for an ecological and environmental emphasis. (HM)

  12. PERFORMANCE CHARACTERISTICS OF PACKAGE WATER TREATMENT PLANTS

    EPA Science Inventory

    This study was undertaken to collect reliable onsite information on the quality of treated water produced by package plants. Six plants in operation year around were selected to be representative of those serving small populations and were monitored to assess their performance. P...

  13. Water management and productivity in planted forests

    NASA Astrophysics Data System (ADS)

    Nettles, J. E.

    2014-09-01

    As climate variability endangers water security in many parts of the world, maximizing the carbon balance of plantation forestry is of global importance. High plant water use efficiency is generally associated with lower plant productivity, so an explicit balance in resources is necessary to optimize water yield and tree growth. This balance requires predicting plant water use under different soil, climate, and planting conditions, as well as a mechanism to account for trade-offs in ecosystem services. Several strategies for reducing the water use of forests have been published but there is little research tying these to operational forestry. Using data from silvicultural and biofuel feedstock research in pine plantation ownership in the southeastern USA, proposed water management tools were evaluated against known treatment responses to estimate water yield, forest productivity, and economic outcomes. Ecosystem impacts were considered qualitatively and related to water use metrics. This work is an attempt to measure and compare important variables to make sound decisions about plantations and water use.

  14. The dynamics of plant cell-wall polysaccharide decomposition in leaf-cutting ant fungus gardens.

    PubMed

    Moller, Isabel E; De Fine Licht, Henrik H; Harholt, Jesper; Willats, William G T; Boomsma, Jacobus J

    2011-01-01

    The degradation of live plant biomass in fungus gardens of leaf-cutting ants is poorly characterised but fundamental for understanding the mutual advantages and efficiency of this obligate nutritional symbiosis. Controversies about the extent to which the garden-symbiont Leucocoprinus gongylophorus degrades cellulose have hampered our understanding of the selection forces that induced large scale herbivory and of the ensuing ecological footprint of these ants. Here we use a recently established technique, based on polysaccharide microarrays probed with antibodies and carbohydrate binding modules, to map the occurrence of cell wall polymers in consecutive sections of the fungus garden of the leaf-cutting ant Acromyrmex echinatior. We show that pectin, xyloglucan and some xylan epitopes are degraded, whereas more highly substituted xylan and cellulose epitopes remain as residuals in the waste material that the ants remove from their fungus garden. These results demonstrate that biomass entering leaf-cutting ant fungus gardens is only partially utilized and explain why disproportionally large amounts of plant material are needed to sustain colony growth. They also explain why substantial communities of microbial and invertebrate symbionts have evolved associations with the dump material from leaf-cutting ant nests, to exploit decomposition niches that the ant garden-fungus does not utilize. Our approach thus provides detailed insight into the nutritional benefits and shortcomings associated with fungus-farming in ants. PMID:21423735

  15. North City Water Reclamation Plant

    E-print Network

    Prevedouros, Panos D.

    Reclamation? Water Reclamation is the process of treating wastewater to be suitable for reuse Not Suitable pipes #12;25 MGD Wastewater 21 MGD to Point Loma 4 MGD Reclaimed Water #12;Social & Environmental Center (MBC) Sludge from North City WRP is sent to MBC for digestion. Sustains a maximum of 3.8 MW 75

  16. Changes in bacterial and eukaryotic communities during sewage decomposition in Mississippi river water.

    PubMed

    Korajkic, Asja; Parfrey, Laura Wegener; McMinn, Brian R; Baeza, Yoshiki Vazquez; VanTeuren, Will; Knight, Rob; Shanks, Orin C

    2015-02-01

    Microbial decay processes are one of the mechanisms whereby sewage contamination is reduced in the environment. This decomposition process involves a highly complex array of bacterial and eukaryotic communities from both sewage and ambient waters. However, relatively little is known about how these communities change due to mixing and subsequent decomposition of the sewage contaminant. We investigated decay of sewage in upper Mississippi River using Illumina sequencing of 16S and 18S rRNA gene hypervariable regions and qPCR for human-associated and general fecal Bacteroidales indicators. Mixtures of primary treated sewage and river water were placed in dialysis bags and incubated in situ under ambient conditions for seven days. We assessed changes in microbial community composition under two treatments in a replicated factorial design: sunlight exposure versus shaded and presence versus absence of native river microbiota. Initial diversity was higher in sewage compared to river water for 16S sequences, but the reverse was observed for 18S sequences. Both treatments significantly shifted community composition for eukaryotes and bacteria (P < 0.05). Data indicated that the presence of native river microbiota, rather than exposure to sunlight, accounted for the majority of variation between treatments for both 16S (R = 0.50; P > 0.001) and 18S (R = 0.91; P = 0.001) communities. A comparison of 16S sequence data and fecal indicator qPCR measurements indicated that the latter was a good predictor of overall bacterial community change over time (rho: 0.804-0.814, P = 0.001). These findings suggest that biotic interactions, such as predation by bacterivorous protozoa, can be critical factors in the decomposition of sewage in freshwater habitats and support the use of Bacteroidales genetic markers as indicators of fecal pollution. PMID:25463929

  17. Continuous Monitoring of Plant Water Potential

    PubMed Central

    Schaefer, Nick L.; Trickett, Edward S.; Ceresa, Anthony; Barrs, Henry D.

    1986-01-01

    Plant water potential was monitored continuously with a Wescor HR-33T dewpoint hygrometer in conjunction with a L51 chamber. This commercial instrument was modified by replacing the AC-DC mains power converter with one stabilized by zener diode controlled transistors. The thermocouple sensor and electrical lead needed to be thermally insulated to prevent spurious signals. For rapid response and faithful tracking a low resistance for water vapor movement between leaf and sensor had to be provided. This could be effected by removing the epidermis either by peeling or abrasion with fine carborundum cloth. A variety of rapid plant water potential responses to external stimuli could be followed in a range of crop plants (sunflower (Helianthus annuus L., var. Hysun 30); safflower (Carthamus tinctorious L., var. Gila); soybean (Glycine max L., var. Clark); wheat (Triticum aestivum L., var. Egret). These included light dark changes, leaf excision, applied pressure to or anaerobiosis of the root system. Water uptake by the plant (safflower, soybean) mirrored that for water potential changes including times when plant water status (soybean) was undergoing cyclical changes. PMID:16664805

  18. Water vapor recovery from plant growth chambers

    NASA Technical Reports Server (NTRS)

    Ray, R. J.; Newbold, D. D.; Colton, R. H.; Mccray, S. B.

    1991-01-01

    NASA is investigating the use of plant growth chambers (PGCs) for space missions and for bases on the moon and Mars. Key to successful development of PGCs is a system to recover and reuse the water vapor that is transpired from the leaves of the plants. A design is presented for a simple, reliable, membrane-based system that allows the recovery, purification, and reuse of the transpired water vapor through control of temperature and humidity levels in PGCs. The system is based on two membrane technologies: (1) dehumidification membrane modules to remove water vapor from the air, and (2) membrane contactors to return water vapor to the PGC (and, in doing so, to control the humidity and temperature within the PGC). The membrane-based system promises to provide an ideal, stable growth environment for a variety of plants, through a design that minimizes energy usage, volume, and mass, while maximizing simplicity and reliability.

  19. Effects of water flow regulation on ecosystem functioning in a Mediterranean river network assessed by wood decomposition.

    PubMed

    Abril, Meritxell; Muñoz, Isabel; Casas-Ruiz, Joan P; Gómez-Gener, Lluís; Barceló, Milagros; Oliva, Francesc; Menéndez, Margarita

    2015-06-01

    Mediterranean rivers are extensively modified by flow regulation practises along their courses. An important part of the river impoundment in this area is related to the presence of small dams constructed mainly for water abstraction purposes. These projects drastically modified the ecosystem morphology, transforming lotic into lentic reaches and increasing their alternation along the river. Hydro-morphologial differences between these reaches indicate that flow regulation can trigger important changes in the ecosystem functioning. Decomposition of organic matter is an integrative process and this complexity makes it a good indicator of changes in the ecosystem. The aim of this study was to assess the effect caused by flow regulation on ecosystem functioning at the river network scale, using wood decomposition as a functional indicator. We studied the mass loss from wood sticks during three months in different lotic and lentic reaches located along a Mediterranean river basin, in both winter and summer. Additionally, we identified the environmental factors affecting decomposition rates along the river orders. The results revealed differences in decomposition rates between sites in both seasons that were principally related to the differences between stream orders. The rates were mainly related to temperature, nutrient concentrations (NO2(-), NO3(2-)) and water residence time. High-order streams with higher temperature and nutrient concentrations exhibited higher decomposition rates compared with low-order streams. The effect of the flow regulation on the decomposition rates only appeared to be significant in high orders, especially in winter, when the hydrological characteristics of lotic and lentic habitats widely varied. Lotic reaches with lower water residence time exhibited greater decomposition rates compared with lentic reaches probably due to more physical abrasion and differences in the microbial assemblages. Overall, our study revealed that in high orders the reduction of flow caused by flow regulation affects the wood decomposition indicating changes in ecosystem functioning. PMID:25721144

  20. Water treatment plants assessment at Talkha power plant.

    PubMed

    El-Sebaie, Olfat D; Abd El-Kerim, Ghazy E; Ramadan, Mohamed H; Abd El-Atey, Magda M; Taha, Sahr Ahmed

    2002-01-01

    Talkha power plant is the only power plant located in El-Mansoura. It generates electricity using two different methods by steam turbine and gas turbine. Both plants drew water from River Nile (208 m3 /h). The Nile raw water passes through different treatment processes to be suitable for drinking and operational uses. At Talkha power plant, there are two purification plants used for drinking water supply (100 m3/h) and for water demineralization supply (108 m3/h). This study aimed at studying the efficiency of the water purification plants. For drinking water purification plant, the annual River Nile water characterized by slightly alkaline pH (7.4-8), high annual mean values of turbidity (10.06 NTU), Standard Plate Count (SPC) (313.3 CFU/1 ml), total coliform (2717/100 ml), fecal coliform (0-2400/100 ml), and total algae (3 x 10(4) org/I). The dominant group of algae all over the study period was green algae. The blue green algae was abundant in Summer and Autumn seasons. The pH range, and the annual mean values of turbidity, TDS, total hardness, sulfates, chlorides, nitrates, nitrites, fluoride, and residual chlorine for purified water were in compliance with Egyptian drinking water standards. All the SPC recorded values with an annual mean value of 10.13 CFU/1 ml indicated that chlorine dose and contact time were not enough to kill the bacteria. However, they were in compliance with Egyptian decree (should not exceed 50 CFU/1 ml). Although the removal efficiency of the plant for total coliform and blue green algae was high (98.5% and 99.2%, respectively), the limits of the obtained results with an annual mean values of 40/100 ml and 15.6 org/l were not in compliance with the Egyptian decree (should be free from total coliform, fecal coliform and blue green algae). For water demineralization treatment plant, the raw water was characterized by slightly alkaline pH. The annual mean values of conductivity, turbidity, and TDS were 354.6 microS/cm, 10.84 NTU, and 214.6 mg/I, respectively. There was an increase in the results of conductivity, turbidity, total hardness, and TDS in carbon filter effluent which was attributed to the desorption of adsorbed ions on the carbon media. The removal efficiencies of turbidity, total hardness, and TDS indicated the high efficiency of the cationic filter. The annual removal efficiencies of conductivity, turbidity, chloride, and TDS proved the efficiency of the anionic filter for removing the dissolved and suspended ions. All of the recorded values of the pH, conductivity, turbidity, chlorides, hardness, and TDS of the mixed bed effluent indicated that the water at this stage was of high quality for boiler feed. The study recommended adjustment of coagulant and residual chlorine doses as well as contact time, and continuous monitoring and maintenance of the different units. PMID:17216967

  1. The Water Circuit of the Plants - Do Plants have Hearts ?

    E-print Network

    Wolfgang Kundt; Eva Gruber

    2006-03-17

    There is a correspondence between the circulation of blood in all higher animals and the circulation of sap in all higher plants - up to heights h of 140 m - through the xylem and phloem vessels. Plants suck in water from the soil, osmotically through the roothair zone, and subsequently lift it osmotically again, and by capillary suction (via their buds, leaves, and fruits) into their crowns. In between happens a reverse osmosis - the endodermis jump - realized by two layers of subcellular mechanical pumps in the endodermis walls which are powered by ATP, or in addition by two analogous layers of such pumps in the exodermis. The thus established root pressure helps forcing the absorbed ground water upward, through the whole plant, and often out again, in the form of guttation, or exudation.

  2. (Plant growth with limited water)

    SciTech Connect

    Not Available

    1992-01-01

    When water is in short supply, soybean stem growth is inhibited by a physical limitation followed in a few hours by metabolic changes that reduce the extensibility of the cell walls. The extensibility then becomes the main limitation. With time, there is a modest recovery in extensibility along with an accumulation of a 28kD protein in the walls of the growth-affected cells. A 3lkD protein that was 80% similar in amino acid sequence also was present but did not accumulate in the walls of the stem cells. In the stem, growth was inhibited and the mRNA for the 28kD protein increased in response to water deprivation but the mRNA for the 3 1 kD protein did not. The roots continued to grow and the mRNA for the 28kD protein did not accumulate but the mRNA for the 3lkD protein did. Thus, there was a tissuespecific response of gene expression that correlated with the contrasting growth response to low water potential in the same seedlings. Further work using immunogold labeling, fluorescence labeling, and western blotting gave evidence that the 28kD protein is located in the cell wall as well as several compartments in the cytoplasm. Preliminary experiments indicate that the 28kD protein is a phosphatase.

  3. Streambank plants vital to water quality

    SciTech Connect

    Sherman, H.

    1989-08-01

    Studies of plants suitable for stabilizing streambanks are described. Sediments caused by soil erosion in Northern California's mountain meadows clog drinking water reservoirs, reduce fish populations, and block hydroelectric dams. Studies of the effect of seasonal climate change on root growth, photosynthesis, and water use of willows and grasses using a below-ground periscope and portable photosynthesis are described. In addition, studies to evaluate the seasonal effect of livestock grazing are in progress.

  4. Succession of Phylogeny and Function During Plant Litter Decomposition (2013 DOE JGI Genomics of Energy and Environment 8th Annual User Meeting)

    SciTech Connect

    Brodie, Eoin

    2013-03-01

    Eoin Brodie of Berkeley Lab on "Succession of phylogeny and function during plant litter decomposition" at the 8th Annual Genomics of Energy & Environment Meeting on March 27, 2013 in Walnut Creek, Calif.

  5. Plant Water Uptake in Drying Soils1

    PubMed Central

    Lobet, Guillaume; Couvreur, Valentin; Meunier, Félicien; Javaux, Mathieu; Draye, Xavier

    2014-01-01

    Over the last decade, investigations on root water uptake have evolved toward a deeper integration of the soil and roots compartment properties, with the goal of improving our understanding of water acquisition from drying soils. This evolution parallels the increasing attention of agronomists to suboptimal crop production environments. Recent results have led to the description of root system architectures that might contribute to deep-water extraction or to water-saving strategies. In addition, the manipulation of root hydraulic properties would provide further opportunities to improve water uptake. However, modeling studies highlight the role of soil hydraulics in the control of water uptake in drying soil and call for integrative soil-plant system approaches. PMID:24515834

  6. Stability of Supported Platinum Sulfuric Acid Decomposition Catalysts for use in Thermochemical Water Splitting Cycles

    SciTech Connect

    Daniel M. Ginosar; Lucia M. Petkovic; Anne W. Glenn; Kyle C. Burch

    2007-03-01

    The activity and stability of several metal oxide supported platinum catalysts were explored for the sulfuric acid decomposition reaction. The acid decomposition reaction is common to several sulfur based thermochemical water splitting cycles. Reactions were carried out using a feed of concentrated liquid sulfuric acid (96 wt%) at atmospheric pressure at temperatures between 800 and 850 °C and a weight hour space velocity of 52 g acid/g catalyst/hr. Reactions were run at these high space velocities such that variations in kinetics were not masked by surplus catalyst. The influence of exposure to reaction conditions was explored for three catalysts; 0.1-0.2 wt% Pt supported on alumina, zirconia and titania. The higher surface area Pt/Al2O3 and Pt/ZrO2 catalysts were found to have the highest activity but deactivated rapidly. A low surface area Pt/TiO2 catalyst was found to have good stability in short term tests, but slowly lost activity for over 200 hours of continuous operation.

  7. Decomposition of environmentally persistent trifluoroacetic acid to fluoride ions by a homogeneous photocatalyst in water.

    PubMed

    Hori, Hisao; Takano, Yuko; Koike, Kazuhide; Takeuchi, Koji; Einaga, Hisahiro

    2003-01-15

    Decomposition of trifluoroacetic acid (TFA) was achieved with a tungstic heteropolyacid photocatalyst H3PW12O40*6H2O in order to develop a technique for measures against TFA stationary sources. This is the first example of C-F bond cleavage in an environmentally harmful perfluoromethyl-group-containing compound using a homogeneous photocatalyst. The catalytic reaction proceeds in water at room temperature under UV-visible light irradiation in the presence of oxygen. The system produces only F- ions and CO2; the (mole of formed F-)/(mole of decomposed TFA) and (mole of formed CO2)/(mole of decomposed TFA) ratios were 2.91 and 2.09, respectively. GC/MS measurements showed no trace of other species such as environmentally undesirable CF4, which is the most stable perfluorocarbon and has a very high global warming potential. When the (initial TFA)/(initial catalyst) molar ratio was 20:1, the turnover number of TFA decomposition reached 5.58 by 72 h of irradiation, accompanying with no catalyst degradation. The catalytic reaction mechanism can be explained by a redox reaction between the catalyst and TFA, involving a photo-Kolbe process. PMID:12564917

  8. Water Movement in Vascular Plants: A Primer

    E-print Network

    Sane, Sanjay P

    2011-01-01

    The origin of land plants was one of the most important events in evolutionary history of earth in terms of its broad impact on metazoan life and the biotic environment. Because vascular tissues enabled land plants to meet the challenges of terrestrial life, it is important to understand the mechanistic basis of water transport through these tissues from soil to the canopy of trees, in some cases almost 100 meters high. The answers to these questions involve not only the biology of plant vasculature, but also the physical properties of water that enable such transport. Although early researchers proposed the hypothesis of cohesion-tension of water as the likely mechanism for sap ascent, the exact mechanism of transport continues to be a hotly debated topic in the field of plant physiology. This debate continues to be enriched with several sophisticated studies on plants of various morphologies growing in diverse habitats. Although a wealth of evidence has upheld the cohesion-tension theory as being fundamenta...

  9. VIEW OF BUILDING 124, THE WATER TREATMENT PLANT, LOOKING NORTHEAST. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF BUILDING 124, THE WATER TREATMENT PLANT, LOOKING NORTHEAST. THE ROCKY FLATS PLANT WATER SUPPLY, TREATMENT, STORAGE, AND DISTRIBUTION SYSTEM HAS OPERATED CONTINUOUSLY SINCE 1953 - Rocky Flats Plant, Water Treatment Plant, West of Third Street, north of Cedar Avenue, Golden, Jefferson County, CO

  10. CHEMICAL DOSER FOR AGUACLARA WATER TREATMENT PLANTS

    EPA Science Inventory

    The design procedure for the nonlinear chemical doser will be validated and extended over a wide range of flow rates. The doser will be tested in several full-scale municipal water treatment plants. We will also generate improved design algorithms for rapid mix, flocculation,...

  11. RECYCLING OF WATER IN POULTRY PROCESSING PLANTS

    EPA Science Inventory

    Studies were conducted on recycling chiller water in a poultry processing plant. The recycling system must be provided with the capability of removing solids and controlling the microbial population. UV was used to control the microbial population. For this control to be effectiv...

  12. WATER REUSE IN A PAPER REPROCESSING PLANT

    EPA Science Inventory

    This project was undertaken to determine the feasibility of water reuse in a paper reprocessing plant with the goal being to 'close the loop' or to demonstrate zero discharge technology. Before the project began, Big Chief Roofing Company at Ardmore, OK, was discharging 7.89 1/se...

  13. Examining an underappreciated control on lignin decomposition in soils? Effects of reactive manganese species on intact plant cell walls

    NASA Astrophysics Data System (ADS)

    Keiluweit, M.; Bougoure, J.; Pett-Ridge, J.; Kleber, M.; Nico, P. S.

    2011-12-01

    Lignin comprises a dominant proportion of carbon fluxes into the soil (representing up to 50% of plant litter and roots). Two lines of evidence suggest that manganese (Mn) acts as a strong controlling factor on the residence time of lignin in soil ecosystems. First, Mn content is highly correlated with litter decomposition in temperate and boreal forest soil ecosystems and, second, microbial agents of lignin degradation have been reported to rely on reactive Mn(III)-complexes to specifically oxidize lignin. However, few attempts have been made to isolate the mechanisms responsible for the apparent Mn-dependence of lignin decomposition in soils. Here we tested the hypothesis that Mn(III)-oxalate complexes may act as a perforating 'pretreatment' for structurally intact plant cell walls. We propose that these diffusible oxidizers are small enough to penetrate and react with non-porous ligno-cellulose in cell walls. This process was investigated by reacting single Zinnia elegans tracheary elements with Mn(III)-oxalate complexes in a continuous flow-through microreactor. The uniformity of cultured tracheary elements allowed us to examine Mn(III)-induced changes in cell wall chemistry and ultrastructure on the micro-scale using fluorescence and electron microscopy as well as synchrotron-based infrared and X-ray spectromicroscopy. Our results show that Mn(III)-complexes substantially oxidize specific lignin components of the cell wall, solubilize decomposition products, severely undermine the cell wall integrity, and cause cell lysis. We conclude that Mn(III)-complexes induce oxidative damage in plant cell walls that renders ligno-cellulose substrates more accessible for microbial lignin- and cellulose-decomposing enzymes. Implications of our results for the rate limiting impact of soil Mn speciation and availability on litter decomposition in forest soils will be discussed.

  14. The catalytic decomposition of silver coated cinnamyl alcohol during water exposure and the formation of silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Dahle, S.; Höfft, O.; Viöl, W.; Maus-Friedrichs, W.

    2014-03-01

    Metastable Induced Electron Spectroscopy, Ultraviolet Photoelectron Spectroscopy (He I), X-ray Photoelectron Spectroscopy, and Quadrupole Mass Spectrometry are employed to study the interaction of water with Ag nanoparticles on cinnamyl alcohol films. The films have been prepared on Au(111) substrates by thermal evaporation. The water adsorption does not result in any chemical interaction with the silver nanoparticles at all, but the cinnamyl alcohol changes its chemical structure significantly. While water molecules induce a reduction of the organic groups, the film thickness seems to decrease. Thus, a decomposition of the cinnamyl alcohol films is proposed. Since no effects are observed during water interaction with pure cinnamyl alcohol films at all, a catalytic reaction appears to take place. No decomposition is found for cinnamyl alcohol adsorbed on a closed silver film, indicating that Ag nanoparticles are required for this catalytical decomposition. The MIES and UPS spectra indicate the existence of a closed metallic film directly after silver adsorption on cinnamyl alcohol, while they suggest the presence of silver nanoparticles after the exposure to water. The formation of silver nanoparticles therefore seems to happen concurrently to the catalytic decomposition of cinnamyl alcohol.

  15. Effect of Oxygen Gas on the Decomposition of Dye by Pulsed Discharge in Water Droplet Spray

    NASA Astrophysics Data System (ADS)

    Nose, Taisuke; Yokoyama, Yuzo; Nakamura, Akira; Minamitani, Yasushi

    Effect of O2 on the decolorization of indigo carmine and on the production of dissolved species such as NO2-, NO3-, O3 and H2O2 in the treatment water by pulsed discharge in water droplet spray was investigated by controlling the O2/N2 ratios as carrier gases in the reactor. The decolorization rate gradually increased with rise in O2 ratio, which reached a constant value in the range of 50% to 90% O2 ratio and decreased in pure O2. The maximum value was about 2 times as high as that of 20% O2 ratio. The decolorization efficiency was not affected by gas flow rate in the range of 4 L/min to 50 L/min. NO2- in the treatment water was only detected in pure N2, but NO3- was produced in O2/N2. NO2- added to the treatment water was not oxidized in pure N2, but was perfectly converted to NO3- in O2/N2. These results implied that hydroxyl radical produced in gas phase does not directly contribute to the oxidation of substances in water. O3 concentration gradually increased with rise in O2 ratio, whereas H2O2 concentration decreased. In the range of 50 to 80% O2 ratio, O3 and H2O2 concentrations were approximately constant value, similar to the trend of decolorization rate. Moreover rate constants on various gas mixing ratio of O2/N2 were determined from the kinetics study. These results suggested that hydroxyl radical produced in the treatment water by the chain reactions of O3 and hydroperoxy radical (HO2·) plays an important role of the decomposition of molecules in water.

  16. CHROMOPHORIC DISSOLVED ORGANIC MATTER (CDOM) DERIVED FROM DECOMPOSITION OF VARIOUS VASCULAR PLANT AND ALGAL SOURCES

    EPA Science Inventory

    Chromophoric dissolved organic (CDOM) in aquatic environments is derived from the microbial decomposition of terrestrial and microbial organic matter. Here we present results of studies of the spectral properties and photoreactivity of the CDOM derived from several organic matter...

  17. Suppressing NOM access to controlled porous TiO2 particles enhances the decomposition of target water contaminants

    EPA Science Inventory

    Suppressing access of natural organic matter (NOM) to TiO2 is a key to the successful photocatalytic decomposition of a target contaminant in water. This study first demonstrates simply controlling the porous structure of TiO2 can significantly improve the selective oxidation.

  18. Study type and plant litter identity modulating the response of litter decomposition to warming, elevated CO2, and elevated O3: A meta-analysis

    NASA Astrophysics Data System (ADS)

    Yue, Kai; Peng, Changhui; Yang, Wanqin; Peng, Yan; Fang, Junmin; Wu, Fuzhong

    2015-03-01

    Plant litter decomposition is one of the most important ecosystem carbon flux processes in terrestrial ecosystems and is usually regarded as sensitive to climate change. The goal of the present study was to examine the effects of changing climate variables on litter decomposition. By synthesizing data from multiple terrestrial ecosystems, we quantified the response of the litter decomposition rate to the independent effects of warming, elevated carbon dioxide (CO2), elevated ozone (O3), and the combined effects of elevated CO2 + elevated O3. Across all case studies, warming increased the litter decomposition rate significantly by 4.4%, but this effect could be reduced as a result of the negatively significant effects of elevated CO2 and elevated CO2 + elevated O3. The combined effects of elevated CO2 + elevated O3 decreased the litter decomposition rate significantly, and the magnitude appeared to be higher than that of the elevated CO2 per se. Moreover, the study type (field versus laboratory), ecosystem type, and plant litter identity and functional traits (growth form and litter form) were all important moderators regulating the response of litter decomposition to climate warming and elevated CO2 and O3. Although litter decomposition rate may show a moderate change as a result of the effects of multiple changing climate variables, the process of litter decomposition would be strongly altered due to the differing mechanisms of the effects of each climate change variable, suggesting that the global carbon cycle and biogeochemistry could be substantially affected.

  19. Plant Anatomy and Reproduction Plants have three main parts Absorb water

    E-print Network

    Brown, Christopher A.

    1 Plant Anatomy and Reproduction Plants have three main parts Absorb water and nutrients support Tissue All but bryophytes have vascular tissue Found in roots, stems, and leaves Three parts Xylem is filled by water further down in the tube. Thus, water constantly moves up the plant as water

  20. Analytical, toxicological and kinetic investigation of decomposition of the drug diclofenac in waters and wastes using gamma radiation.

    PubMed

    Bojanowska-Czajka, A; Kciuk, G; Gumiela, M; Borowiecka, S; Na??cz-Jawecki, G; Koc, A; Garcia-Reyes, J F; Ozbay, D Solpan; Trojanowicz, M

    2015-12-01

    The radiolytic decomposition of the drug diclofenac (DCF), and in limited extent, also two other widely used drugs, ibuprofen and carbamazepine, was examined using liquid chromatography (LC) methods. The efficiency of DCF decomposition was examined in function of the absorbed dose of gamma radiation, and also in the presence of selected scavengers of radicals, which are commonly present in natural waters and wastes. Three different tests were employed for the monitoring of toxicity changes in the irradiated DCF solutions. The LC/mass spectrometry (MS) was used for the determination of products of DCF radiolysis. Using pulse-radiolysis method with the spectrophotometric detection, the rate constant values were determined for reactions of DCF with the main products of water radiolysis: hydroxyl radicals (1.24?±?0.02)?×?10(10) M(-1) s(-1) and hydrated electrons (3.1?±?0.2)?×?10(9) M(-1) s(-1). Their values indicate that both oxidative and reductive processes in radiolytic decomposition of DCF can take place in irradiated diluted aqueous solutions of DCF. The possibility of decomposition of all examined analytes was investigated in samples of river water and hospital waste. Compared to the previous studies, the conducted measurements in real samples were carried out at the concentration levels, which are close to those reported earlier in environmental samples. Graphical abstract ?. PMID:26308920

  1. Optimal reliable design and operation of water distribution systems through decomposition

    NASA Astrophysics Data System (ADS)

    Ostfeld, Avi

    2012-10-01

    Reliability in general, and in water distribution systems in particular, is a measure of probabilistic performance. A system is said to be reliable if it functions properly for a given time interval and within boundary conditions. Although water distribution system reliability has attracted considerable research attention over the last three decades, there is still no consensus on what reliability measures or evaluation methodologies should be used for the design/operation of water distribution systems. No system is perfectly reliable. In every system undesirable events—failures—can cause a decline or interruption in system performance. Failures are of a stochastic nature and are the result of unpredictable events that occur in the system itself and/or in its environs. A least cost design problem with normal design loadings will result in the cheapest system, but this system will have minimum residual capacity. However, if an increased loading (i.e., higher than the normal design) is implemented, the system's capacity will be increased, thus improving its residual capacity. Finding this "virtual increased loading," which results in a minimum cost residual system capacity that sustains a required reliability level, is the essence of the proposed methodology, which follows decomposition. The methodology is demonstrated on two example applications of increasing complexity. The main limitation of the suggested method for further extensions to real sized water distribution systems is the computational effort associated with the computation of the "inner" problem. Exploring the required computational burden divided between the "outer" and "inner" problems is a major challenge for future elaborations of this approach.

  2. Nanoparticle Formation via Copper (II) Acetylacetonate Vapor Decomposition in the Presence of Hydrogen and Water

    E-print Network

    ketone, alcohol, ester, and ether groups are formed. The crystallinity of the particles depends. High volatility and low decomposition temperature of the compounds are useful quantities for industrial

  3. Moisture drives surface decomposition in thawing tundra

    NASA Astrophysics Data System (ADS)

    Hicks Pries, Caitlin E.; Schuur, E. A. G.; Vogel, Jason G.; Natali, Susan M.

    2013-07-01

    Permafrost thaw can affect decomposition rates by changing environmental conditions and litter quality. As permafrost thaws, soils warm and thermokarst (ground subsidence) features form, causing some areas to become wetter while other areas become drier. We used a common substrate to measure how permafrost thaw affects decomposition rates in the surface soil in a natural permafrost thaw gradient and a warming experiment in Healy, Alaska. Permafrost thaw also changes plant community composition. We decomposed 12 plant litters in a common garden to test how changing plant litter inputs would affect decomposition. We combined species' tissue-specific decomposition rates with species and tissue-level estimates of aboveground net primary productivity to calculate community-weighted decomposition constants at both the thaw gradient and warming experiment. Moisture, specifically growing season precipitation and water table depth, was the most significant driver of decomposition. At the gradient, an increase in growing season precipitation from 200 to 300 mm increased mass loss of the common substrate by 100%. At the warming experiment, a decrease in the depth to the water table from 30 to 15 cm increased mass loss by 100%. At the gradient, community-weighted decomposition was 21% faster in extensive than in minimal thaw, but was similar when moss production was included. Overall, the effect of climate change and permafrost thaw on surface soil decomposition are driven more by precipitation and soil environment than by changes to plant communities. Increasing soil moisture is thereby another mechanism by which permafrost thaw can become a positive feedback to climate change.

  4. Performance of small water treatment plants: The case study of Mutshedzi Water Treatment Plant

    NASA Astrophysics Data System (ADS)

    Makungo, R.; Odiyo, J. O.; Tshidzumba, N.

    The performance of small water treatment plants (SWTPs) was evaluated using Mutshedzi WTP as a case study. The majority of SWTPs in South Africa (SA) that supply water to rural villages face problems of cost recovery, water wastages, limited size and semi-skilled labour. The raw and final water quality analyses and their compliance were used to assess the performance of the Mutshedzi WTP. Electrical conductivity (EC), p? and turbidity were measured in the field using a portable multimeter and a turbidity meter respectively. Atomic Absorption Spectrometry and Ion Chromatography were used to analyse metals and non-metals respectively. The results were compared with the Department of Water Affairs (DWA) guidelines for domestic use. The turbidity levels partially exceeded the recommended guidelines for domestic water use of 1 NTU. The concentrations of chemical parameters in final water were within the DWA guidelines for domestic water use except for fluoride, which exceeded the maximum allowable guideline of 1.5 mg/L in August 2009. Mutshedzi WTP had computed compliance for raw and final water analyses ranging from 79% to 93% and 86% to 93% throughout the sampling period, respectively. The results from earlier studies showed that the microbiological quality of final water in Mutshedzi WTP complied with the recommended guidelines, eliminating the slight chance of adverse aesthetic effects and infectious disease transmission associated with the turbidity values between 1 and 5 NTU. The study concluded that Mutshedzi WTP, though moving towards compliance, is still not producing adequate quality of water. Other studies also indicated that the quantity of water produced from Mutshedzi WTP was inadequate. The findings of the study indicate that lack of monitoring of quantity of water supplied to each village, dosage of treatment chemicals, the treatment capacity of the WTP and monitoring the quality of water treated are some of the factors that limit the performance of Mutshedzi WTP. These have been confirmed in literature to be widespread in similar WTPs in SA. It is recommended that water meters be provided and the community be advised to subsidise the cost of water supply. The study recommended that the treatments of turbidity and fluoride should form critical functions of the plant to ensure that final water for domestic use is always safe from any harmful substances or disease causing pathogens. The study concluded that the WTP only needs minor improvement to boost its efficiency with regard to the treatment of raw water. This will also ensure that the plant achieves 100% compliance for final water.

  5. Problems of Terminology in the Teaching of Plant Water Relations

    ERIC Educational Resources Information Center

    Bradbeer, Philip A.; And Others

    1976-01-01

    Recommends use by teachers of new terminology regarding plant water relations. Includes definitions and Greek symbols for the following terms: water potential, water potential of cell, osmotic potential, matric potential, and pressure potential. (CS)

  6. Water reuse for electric utility and cogeneration plants -- important considerations

    SciTech Connect

    Selby, K.A.; Tvedt, T.J. Jr.

    1998-12-31

    Electric utility and cogeneration (Cogen) plants offer numerous possibilities for the reuse of water in both boiler and cooling systems. However, these plants have specific water quality requirements. Careful evaluation of potential sources of reuse water is needed and water treatment processes must be tailored to the site specific needs of a particular plant, These needs vary based on the design of the plant and often on the geographic location. This paper describes the water quality needs in electric utility and cogeneration facilities and the opportunities for reuse waters to fulfill these needs.

  7. Plant herbivory responses through changes in leaf quality have no effect on subsequent leaf-litter decomposition in a neotropical rain forest tree community.

    PubMed

    Cárdenas, Rafael E; Hättenschwiler, Stephan; Valencia, Renato; Argoti, Adriana; Dangles, Olivier

    2015-08-01

    It is commonly accepted that plant responses to foliar herbivory (e.g. plant defenses) can influence subsequent leaf-litter decomposability in soil. While several studies have assessed the herbivory-decomposability relationship among different plant species, experimental tests at the intra-specific level are rare, although critical for a mechanistic understanding of how herbivores affect decomposition and its consequences at the ecosystem scale. Using 17 tree species from the Yasuní National Park, Ecuadorian Amazonia, and applying three different herbivore damage treatments, we experimentally tested whether the plant intra-specific responses to herbivory, through changes in leaf quality, affect subsequent leaf-litter decomposition in soil. We found no effects of herbivore damage on the subsequent decomposition of leaf litter within any of the species tested. Our results suggest that leaf traits affecting herbivory are different from those influencing decomposition. Herbivore damage showed much higher intra-specific than inter-specific variability, while we observed the opposite for decomposition. Our findings support the idea that interactions between consumers and their resources are controlled by different factors for the green and the brown food-webs in tropical forests, where herbivory may not necessarily generate any direct positive or negative feedbacks for nutrient cycling. PMID:25771942

  8. Improvement of water treatment at thermal power plants

    NASA Astrophysics Data System (ADS)

    Larin, B. M.; Bushuev, E. N.; Larin, A. B.; Karpychev, E. A.; Zhadan, A. V.

    2015-04-01

    Prospective and existing technologies for water treatment at thermal power plants, including pretreatment, ion exchange, and membrane method are considered. The results obtained from laboratory investigations and industrial tests of the proposed technologies carried out at different thermal power plants are presented. The possibilities of improving the process and environmental indicators of water treatment plants are shown.

  9. BARIUM AND RADIUM IN WATER TREATMENT PLANT WASTES

    EPA Science Inventory

    Water treatment plants at nine locations (10 plants) in Illinois and Iowa were studied to determine the characteristics and disposal practices for the sludge, brine, and backwash water containing radium (Ra) and/or barium (Ba). The treatment processes in these ten plants include ...

  10. DECOMPOSITION OF TRIHALOACETIC ACIDS AND FORMATION OF THE CORRESPONDING TRIHALOMETHANES IN DRINKING WATER. (R826834)

    EPA Science Inventory

    The decomposition of trihaloacetic acids [bromodichloroacetic acid (BDCAA), dibromochloroacetic acid (DBCAA), tribromoacetic acid (TBAA)], and the formation of the corresponding trihalomethanes [bromodichloromethane (BDCM), dibromochloromethane (DBCM), tribromomethane (TBM)] w...

  11. A new conceptual model on the fate and controls of fresh and pyrolized plant litter decomposition

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The leaching of dissolved organic matter (DOM) from fresh and pyrolyzed aboveground plant inputs to the soil is a major pathway by which decomposing aboveground plant material contributes to soil organic matter formation. Understanding how aboveground plant input chemical traits control the partiti...

  12. Mass transfer in fuel cells. [electron microscopy of components, thermal decomposition of Teflon, water transport, and surface tension of KOH solutions

    NASA Technical Reports Server (NTRS)

    Walker, R. D., Jr.

    1973-01-01

    Results of experiments on electron microscopy of fuel cell components, thermal decomposition of Teflon by thermogravimetry, surface area and pore size distribution measurements, water transport in fuel cells, and surface tension of KOH solutions are described.

  13. The impact of the invasive shrub Lonicera maackii on the decomposition dynamics of a native plant community.

    PubMed

    Poulette, Megan M; Arthur, Mary A

    2012-03-01

    Invasive plants may have variable effects within a given environment depending on their interactions with the dominant native species, yet little research has examined such species-species interactions within a site. Savanna trees with nonoverlapping canopies offer an ideal opportunity to assess associated changes in the ecosystem processes that result from interactions between an invasive species and different native tree species. We examined the influence of the exotic invasive shrub Lonicera maackii on decomposition dynamics under three native tree species: Fraxinus quadrangulata, Quercus muehlenbergii, and Carya ovata. Litter decomposition rates and litter C and N were evaluated over two years using single- and mixed-species litterbags (L. maackii and individual tree species litter); microarthropod abundance was measured at 6 weeks using Tulgren funnels. Litter from the invasive L. maackii decomposed and lost N more rapidly than the litter of the three native tree species. The rate at which L. maackii decomposed depended on its location, with L. maackii litter decomposing and losing N more rapidly under C. ovata than under the other two native tree species. Mixing L. maackii with the native species' litter did not accelerate litter mass loss overall but did result in synergistic N losses at variable times throughout the experiment, further highlighting the variable interaction between native species and L. maackii. Nitrogen loss was significantly higher than expected in mixtures of C. ovata + L. maackii litter at 6 weeks, in F. quadrangulata + L. maackii litter at 12 weeks, and in Q. muehlenbergii + L. maackii litter at 24 weeks. If the effects of invasive species on certain ecosystem processes, such as litter decomposition, are strongly influenced by their association with native species, this could suggest the need for a more nuanced understanding of the vulnerability of ecosystem processes to invasions of L. maackii and potentially other invasive species. PMID:22611844

  14. A class-information-based penalized matrix decomposition for identifying plants core genes responding to abiotic stresses.

    PubMed

    Liu, Jin-Xing; Liu, Jian; Gao, Ying-Lian; Mi, Jian-Xun; Ma, Chun-Xia; Wang, Dong

    2014-01-01

    In terms of making genes expression data more interpretable and comprehensible, there exists a significant superiority on sparse methods. Many sparse methods, such as penalized matrix decomposition (PMD) and sparse principal component analysis (SPCA), have been applied to extract plants core genes. Supervised algorithms, especially the support vector machine-recursive feature elimination (SVM-RFE) method, always have good performance in gene selection. In this paper, we draw into class information via the total scatter matrix and put forward a class-information-based penalized matrix decomposition (CIPMD) method to improve the gene identification performance of PMD-based method. Firstly, the total scatter matrix is obtained based on different samples of the gene expression data. Secondly, a new data matrix is constructed by decomposing the total scatter matrix. Thirdly, the new data matrix is decomposed by PMD to obtain the sparse eigensamples. Finally, the core genes are identified according to the nonzero entries in eigensamples. The results on simulation data show that CIPMD method can reach higher identification accuracies than the conventional gene identification methods. Moreover, the results on real gene expression data demonstrate that CIPMD method can identify more core genes closely related to the abiotic stresses than the other methods. PMID:25180509

  15. A Class-Information-Based Penalized Matrix Decomposition for Identifying Plants Core Genes Responding to Abiotic Stresses

    PubMed Central

    Liu, Jin-Xing; Liu, Jian; Gao, Ying-Lian; Mi, Jian-Xun; Ma, Chun-Xia; Wang, Dong

    2014-01-01

    In terms of making genes expression data more interpretable and comprehensible, there exists a significant superiority on sparse methods. Many sparse methods, such as penalized matrix decomposition (PMD) and sparse principal component analysis (SPCA), have been applied to extract plants core genes. Supervised algorithms, especially the support vector machine-recursive feature elimination (SVM-RFE) method, always have good performance in gene selection. In this paper, we draw into class information via the total scatter matrix and put forward a class-information-based penalized matrix decomposition (CIPMD) method to improve the gene identification performance of PMD-based method. Firstly, the total scatter matrix is obtained based on different samples of the gene expression data. Secondly, a new data matrix is constructed by decomposing the total scatter matrix. Thirdly, the new data matrix is decomposed by PMD to obtain the sparse eigensamples. Finally, the core genes are identified according to the nonzero entries in eigensamples. The results on simulation data show that CIPMD method can reach higher identification accuracies than the conventional gene identification methods. Moreover, the results on real gene expression data demonstrate that CIPMD method can identify more core genes closely related to the abiotic stresses than the other methods. PMID:25180509

  16. Prediction of the Maximum Temperature for Life Based on the Stability of Metabolites to Decomposition in Water

    PubMed Central

    Bains, William; Xiao, Yao; Yu, Changyong

    2015-01-01

    The components of life must survive in a cell long enough to perform their function in that cell. Because the rate of attack by water increases with temperature, we can, in principle, predict a maximum temperature above which an active terrestrial metabolism cannot function by analysis of the decomposition rates of the components of life, and comparison of those rates with the metabolites’ minimum metabolic half-lives. The present study is a first step in this direction, providing an analytical framework and method, and analyzing the stability of 63 small molecule metabolites based on literature data. Assuming that attack by water follows a first order rate equation, we extracted decomposition rate constants from literature data and estimated their statistical reliability. The resulting rate equations were then used to give a measure of confidence in the half-life of the metabolite concerned at different temperatures. There is little reliable data on metabolite decomposition or hydrolysis rates in the literature, the data is mostly confined to a small number of classes of chemicals, and the data available are sometimes mutually contradictory because of varying reaction conditions. However, a preliminary analysis suggests that terrestrial biochemistry is limited to environments below ~150–180 °C. We comment briefly on why pressure is likely to have a small effect on this. PMID:25821932

  17. Pt/TiO2 (Rutile) Catalysts for Sulfuric Acid Decomposition in Sulfur-Based Thermochemical Water-Splitting Cycles

    SciTech Connect

    L. M. Petkovic; D. M. Ginosar; H. W. Rollins; K. C. Burch; P. J. Pinhero; H. H. Farrell

    2008-04-01

    Thermochemical cycles consist of a series of chemical reactions to produce hydrogen from water at lower temperatures than by direct thermal decomposition. All the sulfur-based cycles for water splitting employ the sulfuric acid decomposition reaction. This work reports the studies performed on platinum supported on titania (rutile) catalysts to investigate the causes of catalyst deactivation under sulfuric acid decomposition reaction conditions. Samples of 1 wt% Pt/TiO2 (rutile) catalysts were submitted to flowing concentrated sulfuric acid at 1123 K and atmospheric pressure for different times on stream (TOS) between 0 and 548 h. Post-operation analyses of the spent catalyst samples showed that Pt oxidation and sintering occurred under reaction conditions and some Pt was lost by volatilization. Pt loss rate was higher at initial times but total loss appeared to be independent of the gaseous environment. Catalyst activity showed an initial decrease that lasted for about 66 h, followed by a slight recovery of activity between 66 and 102 h TOS, and a period of slower deactivation after 102 h TOS. Catalyst sulfation did not seem to be detrimental to catalyst activity and the activity profile suggested that a complex dynamical situation involving platinum sintering, volatilization, and oxidation, along with TiO2 morphological changes affected catalyst activity in a non-monotonic way.

  18. Gasification characteristics of an activated carbon catalyst during the decomposition of hazardous waste material in supercritical water

    SciTech Connect

    Matsumura, Yukihiko; Nuessle, F.W.; Antal, M.J. Jr.

    1996-12-31

    Recently, carbonaceous materials including activated carbon were proven to be effective catalysts for hazardous waste gasification in supercritical water. Using coconut shell activated carbon catalyst, complete decomposition of industrial organic wastes including methanol and acetic acid was achieved. During this process, the total mass of the activated carbon catalyst changes by two competing processes: a decrease in weight via gasification of the carbon by supercritical water, or an increase in weight by deposition of carbonaceous materials generated by incomplete gasification of the biomass feedstocks. The deposition of carbonaceous materials does not occur when complete gasification is realized. Gasification of the activated carbon in supercritical water is often favored, resulting in changes in the quality and quantity of the catalyst. To thoroughly understand the hazardous waste decomposition process, a more complete understanding of the behavior of activated carbon in pure supercritical water is needed. The gasification rate of carbon by water vapor at subcritical pressures was studied in relation to coal gasification and generating activated carbon.

  19. The impact of uranium mine contamination of soils on plant litter decomposition.

    PubMed

    Freitas, Ana C; Rodrigues, Dina; Rocha-Santos, Teresa A P; Gonçalves, Fernando; Duarte, Armando C; Pereira, Ruth

    2014-11-01

    As part of a tier 3 risk assessment performed for a uranium mining area, the ability of soils with different degrees of metal contamination to degrade organic matter was assessed using litter bags filled with leaves of Quercus robur, Pinus pinaster, Salix atrocinerea, or a mixture of the three species. Litter bags were exposed at different sites within the mine area and at a reference area for 3, 6, 9, and 12 months. Biomass loss, nitrogen (N), phosphorus (P), carbon (C) and total fatty acid, total phenolic, and ergosterol contents were assessed for each litter bag retrieved from the field. The decomposition of litter at each site seemed to be governed by a complex interaction of many different factors. After 12 months of exposure, leaves from the most contaminated sites were distinguishable from those from the reference site. In the reference site, the greatest percentages of biomass loss were attained by Q. robur and P. pinaster leaves. These species displayed the second highest and the lowest C-to-N ratios, respectively. In addition, the high P content of the litter from these two species may have favored microbial colonization. The results suggest that the decomposition of P. pinaster and Q. robur leaves may have been favored at the reference site by the high abundance of both species at this site and the subsequent adaptation of the microbial community to their litter. Our study shows that different species of leaf litter should be used to discriminate between contaminated sites with different levels of contamination. PMID:24823679

  20. Survival strategies of plants during water stress

    SciTech Connect

    Scheuermann, R.; Stuhlfauth, T.; Sueltemeyer, D.; Fock, H.

    1989-04-01

    Fluorescence and gas exchange of bean, maize, sunflower and wooly foxglove were simultaneously measured at 250 {mu}mol quanta/m{sup 2}/s. Under severe water stresses conditions about 40% of the photochemical energy was converted to heat at PS II. This is interpreted as a protective mechanism against photoinhibitory damage when net CO{sub 2} uptake is reduced by about 70%. After {sup 14}CO{sub 2} gas exchange, only in bean was a homogeneous distribution of radioactivity over the leaf observed. In all other plants we found a patchy distribution of regions with either an intensive or a reduced gas exchange. We conclude that CO{sub 2}-recycling (photorespiration and reassimilation) behind closed stomata also contributed to energy dissipation under severe stress conditions.

  1. Outdoor Water Use Conservation through Native Plants Shapiro, Chan, Carson, Tayag Outdoor Water Use Conservation through Native Plants

    E-print Network

    Pasternack, Gregory B.

    for regular turfgrass and buffalo grass (developed by UC Davis as a water efficient alternative to turfgrassOutdoor Water Use Conservation through Native Plants Shapiro, Chan, Carson, Tayag Outdoor Water Use, the front lawn is one of the greatest consumers of outdoor water use. Because of population growth, water

  2. Effect of carbon tetrachloride on sonochemical decomposition of methyl orange in water.

    PubMed

    Okitsu, Kenji; Kawasaki, Kotaro; Nanzai, Ben; Takenaka, Norimichi; Bandow, Hiroshi

    2008-03-01

    Two types of sonicators were used for the sonochemical decomposition of methyl orange (MO) in the presence and absence of carbon tetrachloride (CCl4): One is a 45kHz ultrasonic cleaning bath (a low intensity sonicator) and the other is a 200kHz ultrasonic reactor (a high intensity sonicator). It was clearly confirmed that the rates of the sonochemical decomposition of MO increased with increasing the concentration of CCl4 in both sonicators. The enhancement effect of CCl4 was much higher in the high intensity sonicator than in the low intensity one: by the addition of 100ppm of CCl4, the decomposition ratio of MO with the high intensity sonicator became 41 times larger, while that with the low intensity sonicator became 4.8 times larger. Based on the obtained results, it was suggested that the formed cavitation phenomenon was different between sonicators. It was also suggested that the sonochemical decomposition of MO in the presence of CCl4 would be useful to evaluate the sonochemical efficiency, because the rate of MO decomposition can be effectively enhanced by the sonolysis of CCl4. PMID:18166211

  3. Water Conservation with Urban Landscape Plants 

    E-print Network

    Hip, B. W.; Giordano, C.; Simpson, B.

    1983-01-01

    used in the lysimeter study were buffalograss, St. Augustine grass, cenizo, boxwood and Texas barberry. All plants are native to Texas except boxwood and St. Augustine grass. Four lysimeters were planted to each plant type. This allowed two moisture...

  4. Carbon Assimilation Pathways, Water Relationships and Plant Ecology.

    ERIC Educational Resources Information Center

    Etherington, John R.

    1988-01-01

    Discusses between-species variation in adaptation of the photosynthetic mechanism to cope with wide fluctuations of environmental water regime. Describes models for water conservation in plants and the role of photorespiration in the evolution of the different pathways. (CW)

  5. Gasification characteristics of an activated carbon catalyst during the decomposition of hazardous waste materials in supercritical water

    SciTech Connect

    Matsumura, Yukihiko; Nuessle, F.W.; Antal, M.J. Jr.

    1996-10-01

    Recently, carbonaceous materials were proved to be effective catalysts for hazardous waste decomposition in supercritical water. Gasification of the carbonaceous catalyst itself is also expected, however, under supercritical conditions. Thus, it is essential to determine the gasification rate of the carbonaceous materials during this process to determine the active lifetime of the catalysts. For this purpose, the gasification characteristics of granular coconut shell activated carbon in supercritical water alone (600-650{degrees}C, 25.5-34.5 MPa) were investigated. The gasification rate at subatmospheric pressure agreed well with the gasification rate at supercritical conditions, indicating the same reaction mechanism. Methane generation under these conditions is via pyrolysis, and thus is not affected by the water pressure. An iodine number increase of 25% was observed as a result of the supercritical water gasification.

  6. Detection of Plant Water Content with Needle-Type In-Situ Water Content Sensor

    NASA Astrophysics Data System (ADS)

    Katayanagi, Hitoshi; Miki, Norihisa

    A needle-type water content sensor with a polyethersulfone (PES) polymer membrane was developed for the low-invasive, direct in-situ measurement of plant water content (PWC) in prior work. In this paper we demonstrate a measurement of plant water stress that represents the demand for water of the plant and greatly affects its sweetness. We inserted the sensor into a stalk of strawberry (Fragaria×ananassa) and soil. The variation in both the plant and the soil water content were successfully detected, which revealed the delay between variation in the plant water stress and soil water content after irrigation. Such delay could only be detected by the proposed sensor that could directly measure the variation of PWC in situ and continuously. The experiments also showed the variation in the signals as a function of detection sites and suggested that the detection sites of plant water stress need to be considered when the sensor is applied to irrigation culture.

  7. BENEFICIAL DISPOSAL OF WATER PURIFICATION PLANT SLUDGES IN WASTEWATER TREATMENT

    EPA Science Inventory

    This report discusses the advantages and disadvantages of the disposal of waste alum sludge from a water treatment plant to a municipal wastewater treatment plant and is submitted in fulfillment of Grant No. 803336-01 by Novato Sanitary District and North Marin County Water Distr...

  8. Air-cooled condensers eliminate plant water use

    SciTech Connect

    Wurtz, W.; Peltier, R.

    2008-09-15

    River or ocean water has been the mainstay for condensing turbine exhaust steam since the first steam turbine began generating electricity. A primary challenge facing today's plant developers, especially in drought-prone regions, is incorporating processes that reduce plant water use and consumption. One solution is to shed the conventional mindset that once-through cooling is the only option and adopt dry cooling technologies that reduce plant water use from a flood to a few sips. A case study at the Astoria Energy plant, New York City is described. 14 figs.

  9. Mechanism and Mitigation of the Decomposition of an Oxorhenium Complex-Based Heterogeneous Catalyst for Perchlorate Reduction in Water.

    PubMed

    Liu, Jinyong; Chen, Xi; Wang, Yin; Strathmann, Timothy J; Werth, Charles J

    2015-11-01

    A biomimetic heterogeneous catalyst combining palladium nanoparticles and an organic ligand-coordinated oxorhenium complex on activated carbon, Re(hoz)2-Pd/C, was previously developed and shown to reduce aqueous perchlorate (ClO4(-)) with H2 at a rate ?100 times faster than the first generation ReOx-Pd/C catalyst prepared from perrhenate (ReO4(-)). However, the immobilized Re(hoz)2 complex was shown to partially decompose and leach into water as ReO4(-), leading to an irreversible loss of catalytic activity. In this work, the stability of the immobilized Re(hoz)2 complex is shown to depend on kinetic competition between three processes: (1) Re(V)(hoz)2 oxidation by ClO4(-) and its reduction intermediates ClOx(-), (2) Re(VII)(hoz)2 reduction by Pd-activated hydrogen, and (3) hydrolytic Re(VII)(hoz)2 decomposition. When Re(V)(hoz)2 oxidation is faster than Re(VII)(hoz)2 reduction, the Re(VII)(hoz)2 concentration builds up and leads to hydrolytic decomposition to ReO4(-) and free hoz ligand. Rapid Re(V)(hoz)2 oxidation is mainly promoted by highly reactive ClOx(-) formed from the reduction of ClO4(-). To mitigate Re(hoz)2 decomposition and preserve catalytic activity, ruthenium (Ru) and rhodium (Rh) were evaluated as alternative H2 activators to Pd. Rh showed superior activity for reducing the ClO3(-) intermediate to Cl(-), thereby preventing ClOx(-) buildup and lowering Re complex decomposition in the Re(hoz)2-Rh/C catalyst. In contrast, Ru showed the lowest ClO3(-) reduction activity and resulted in the most Re(hoz)2 decomposition among the Re(hoz)2-M/C catalysts. This work highlights the importance of using mechanistic insights from kinetic and spectroscopic tests to rationally design water treatment catalysts for enhanced performance and stability. PMID:26422179

  10. Plant experience with temporary reverse osmosis makeup water systems

    SciTech Connect

    Polidoroff, C.

    1986-01-01

    Pacific Gas and Electric (PG and E) Company's Diablo Canyon Power Plant (DCPP), which is located on California's central coast, has access to three sources of raw water: creek water, well water, and seawater. Creek and well water are DCPP's primary sources of raw water; however, because their supply is limited, these sources are supplemented with seawater. The purpose of this paper is to discuss the temporary, rental, reverse osmosis systems used by PG and E to process DCPP's raw water into water suitable for plant makeup. This paper addresses the following issues: the selection of reverse osmosis over alternative water processing technologies; the decision to use vendor-operated temporary, rental, reverse osmosis equipment versus permanent PG and E-owned and -operated equipment; the performance of DCPP's rental reverse osmosis systems; and, the lessons learned from DCPP's reverse osmosis system rental experience that might be useful to other plants considering renting similar equipment.

  11. Filtration plant for drinking water James Tarchala [1

    E-print Network

    Kostic, Milivoje M.

    Filtration plant for drinking water James Tarchala [1] Alexandre Selhorst [2] Cheny Thao [3] 1 2 3 Riley, Wang, Aaron Nolan (Not Pictured) 12/1/2014 #12;Reclaiming waste HEAT TO PRE- HEAT WATER IN a FACTORY HOT WATER SYSTEM Group 5: Joseph Von Arx(1) Aaron McKeown(2) Kyle Swanson(3) Ian Klecka(4) 1 2 3 4

  12. Optimization of Energy and Water Consumption in Cornbased Ethanol Plants

    E-print Network

    Grossmann, Ignacio E.

    and waste water discharge. We consider the corn-based ethanol plant reported in Karuppiah et al. (2008 industrial operation and waste water is no longer discharged. Keywords: Energy, Biofuels, Alternative fuels, including the treatment and recycling of waste water (Petrakis, 2008) as shown later in this paper. The task

  13. Resistance to Water Flow in the Sorghum Plant 1

    PubMed Central

    Meyer, Wayne S.; Ritchie, Joe T.

    1980-01-01

    Knowledge of the location and magnitude of the resistance to water flow in a plant is fundamental for describing whole plant response to water stress. The reported magnitudes of these resistances vary widely, principally because of the difficulty of measuring water potential within the plant. A number of interrelated experiments are described in which the water potential of a covered, nontranspiring leaf attached to a transpiring sorghum plant (Sorghum bicolor [L.] Moench) was used as a measure of the potential at the root-shoot junction. This allowed a descriptive evaluation of plant resistance to be made. The water potentials of a covered, nontranspiring leaf and a nonabsorbing root in solution, both attached to an otherwise actively transpiring and absorbing plant, were found to be similar. This supported the hypothesis that covered leaf water potential was equilibrating at a point shared by the vascular connections of both leaves and roots, i.e. the nodal complex of the root-shoot junction or crown. The difference in potential between a covered and exposed leaf together with calculated individual leaf transpiration rates were used to evaluate the resistance between the plant crown and the exposed leaf lamina called the connection resistance. There was an apparent decrease in the connection resistance as the transpiration rate increased; this is qualitatively explained as plant capacitance. Assuming that the covered leaf water potential was equal to that in the root xylem at the point of water absorption in the experimental plants with relatively short root axes, calculated radial root resistances were strongly dependent on the transpiration rate. For plants with moderate to high transpiration rates the roots had a slightly larger resistance than the shoots. PMID:16661138

  14. The crystallization water of gypsum rocks is a relevant water source for plants.

    PubMed

    Palacio, Sara; Azorín, José; Montserrat-Martí, Gabriel; Ferrio, Juan Pedro

    2014-01-01

    Some minerals, like gypsum, hold water in their crystalline structure. Although still unexplored, the use of such crystallization water by organisms would point to a completely new water source for life, critical under dry conditions. Here we use the fact that the isotopic composition of free water differs from gypsum crystallization water to show that plants can use crystallization water from the gypsum structure. The composition of the xylem sap of gypsum plants during summer shows closer values to gypsum crystallization water than to free soil water. Crystallization water represents a significant water source for organisms growing on gypsum, especially during summer, when it accounts for 70-90% of the water used by shallow-rooted plants. Given the widespread occurrence of gypsum in dry lands throughout the Earth and in Mars, these results may have important implications for arid land reclamation and exobiology. PMID:25130772

  15. Cadaver decomposition in terrestrial ecosystems

    NASA Astrophysics Data System (ADS)

    Carter, David O.; Yellowlees, David; Tibbett, Mark

    2007-01-01

    A dead mammal (i.e. cadaver) is a high quality resource (narrow carbon:nitrogen ratio, high water content) that releases an intense, localised pulse of carbon and nutrients into the soil upon decomposition. Despite the fact that as much as 5,000 kg of cadaver can be introduced to a square kilometre of terrestrial ecosystem each year, cadaver decomposition remains a neglected microsere. Here we review the processes associated with the introduction of cadaver-derived carbon and nutrients into soil from forensic and ecological settings to show that cadaver decomposition can have a greater, albeit localised, effect on belowground ecology than plant and faecal resources. Cadaveric materials are rapidly introduced to belowground floral and faunal communities, which results in the formation of a highly concentrated island of fertility, or cadaver decomposition island (CDI). CDIs are associated with increased soil microbial biomass, microbial activity (C mineralisation) and nematode abundance. Each CDI is an ephemeral natural disturbance that, in addition to releasing energy and nutrients to the wider ecosystem, acts as a hub by receiving these materials in the form of dead insects, exuvia and puparia, faecal matter (from scavengers, grazers and predators) and feathers (from avian scavengers and predators). As such, CDIs contribute to landscape heterogeneity. Furthermore, CDIs are a specialised habitat for a number of flies, beetles and pioneer vegetation, which enhances biodiversity in terrestrial ecosystems.

  16. 78 FR 35330 - Initial Test Programs for Water-Cooled Nuclear Power Plants

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-12

    ...Programs for Water-Cooled Nuclear Power Plants AGENCY: Nuclear Regulatory...Programs for Water-Cooled Nuclear Power Plants.'' This guide describes...ITPs) for light water cooled nuclear power plants. ADDRESSES: Please...

  17. 77 FR 73056 - Initial Test Programs for Water-Cooled Nuclear Power Plants

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-07

    ...Programs for Water-Cooled Nuclear Power Plants AGENCY: Nuclear Regulatory...Programs for Water-Cooled Nuclear Power Plants.'' This guide describes...ITPs) for light water cooled nuclear power plants. DATES: Submit comments...

  18. Water use, productivity and interactions among desert plants

    SciTech Connect

    Ehleringer, J.R.

    1992-11-17

    Water plays a central role affecting all aspects of the dynamics in aridland ecosystems. Productivity, stability, and competitive interactions among ecosystem components within aridlands are key processes related directly to water in deserts. The ecological studies in this project revolve around one fundamental premise: that integrated aspects of plant metabolism provide insight into the structure and function of plant communities and ecosystems. While it is difficult to extrapolate from instantaneous physiological observations to higher scales, such as whole plant performance or to interactions between plants as components of ecosystems, several key aspects of plant metabolism are scalable. Analyses of stable isotopic composition in plant tissues at natural abundance levels provide a useful tool that can provide insight into the consequences of physiological processes over temporal and spatial scales. Some plant processes continuously fractionate among light and heavy stable isotopic forms of an element; over time this results in integrated measures of plant metabolism. For example, carbon isotope fractionation during photosynthesis results in leaf carbon isotopic composition that is a measure of the set-point for photosynthetic metabolism and of water-use efficiency. Thus it provides information on the temporal scaling of a key physiological process. In contrast, hydrogen is not fractionated during water uptake through the root. Soil water availability in shallow, deep, and/or groundwater layers vary spatially; therefore hydrogen isotope ratios of xylem sap provide a direct measure of the water source currently used by a plant. The longer-term record of carbon and hydrogen isotope ratios is recorded annually in xylem tissues (tree rings). The research in this project addresses variation in stable isotopic composition of aridland plants and its consequences for plant performance and community-level interactions.

  19. Water recovery using waste heat from coal fired power plants.

    SciTech Connect

    Webb, Stephen W.; Morrow, Charles W.; Altman, Susan Jeanne; Dwyer, Brian P.

    2011-01-01

    The potential to treat non-traditional water sources using power plant waste heat in conjunction with membrane distillation is assessed. Researchers and power plant designers continue to search for ways to use that waste heat from Rankine cycle power plants to recover water thereby reducing water net water consumption. Unfortunately, waste heat from a power plant is of poor quality. Membrane distillation (MD) systems may be a technology that can use the low temperature waste heat (<100 F) to treat water. By their nature, they operate at low temperature and usually low pressure. This study investigates the use of MD to recover water from typical power plants. It looks at recovery from three heat producing locations (boiler blow down, steam diverted from bleed streams, and the cooling water system) within a power plant, providing process sketches, heat and material balances and equipment sizing for recovery schemes using MD for each of these locations. It also provides insight into life cycle cost tradeoffs between power production and incremental capital costs.

  20. Drinkable rocks: plants can use crystallization water from gypsum

    NASA Astrophysics Data System (ADS)

    Palacio, Sara; Azorín, José; Montserrat-Martí, Gabriel; Ferrio, Juan Pedro

    2015-04-01

    Some minerals hold water in their crystalline structure. Such is the case of gypsum (CaSO4•2H2O), a rock forming mineral present in the arid and semi-arid regions of the five continents, including the dry most areas of the planet. Gypsum is also extensively found on Mars, where it constitutes a targeted substrate for the search of life. Under natural conditions and depending on the temperature, pressure, and dissolved electrolytes or organics, gypsum may lose crystallization water molecules, becoming bassanite (i.e. hemihydrate: CaSO4•½H2O) or anhydrite (CaSO4). As crystallization water can account for up to 20.8% of gypsum weight, it has been suggested that it could constitute a relevant source of water for organisms, particularly during summer. This suggestion is consistent with the phenology observed in some shallow-rooted plants growing on gypsum, which remain active when drought is intense, and with the increased soil moisture of gypsum soils during summer as compared to surrounding non-gypsum soils. Here we use the fact that the isotopic composition of free water differs from gypsum crystallization water to show that plants can use crystallization water from the gypsum structure. The composition of the xylem sap of gypsum plants during summer shows closer values to gypsum crystallization water than to free soil water. Crystallization water represents a significant water source for organisms growing on gypsum, especially during summer, when it accounts for 70-90% of the water used by shallow-rooted plants. These results significantly modify the current paradigm on water use by plants, where water held in the crystalline structure of mineral rocks is not regarded as a potential source. Given the existence of gypsum on the surface of Mars and its widespread occurrence on arid and semi-arid regions worldwide, our results have important implications for exobiology, the study of life under extreme conditions and arid land reclamation.

  1. Multibubble plasma production and solvent decomposition in water by slot-excited microwave discharge

    NASA Astrophysics Data System (ADS)

    Ishijima, T.; Hotta, H.; Sugai, H.; Sato, M.

    2007-09-01

    Intense microwaves are injected from a slot antenna into water partly filling a metal vessel. When the vessel is evacuated to saturated vapor pressure (˜5×103Pa) of water, microwave breakdown gives rise to plasmas in many bubbles in the boiling water. Gas bubbling technique enables production of multibubble plasmas in water even at atmospheric pressure. Optical emissions from the exited species are investigated to identify radical species in water. In order to demonstrate application to purification of polluted water, methylene blue and trichlorethylene solution in 8l water were observed to rapidly decrease with multibubble plasma treatment.

  2. Multibubble plasma production and solvent decomposition in water by slot-excited microwave discharge

    SciTech Connect

    Ishijima, T.; Hotta, H.; Sugai, H.; Sato, M.

    2007-09-17

    Intense microwaves are injected from a slot antenna into water partly filling a metal vessel. When the vessel is evacuated to saturated vapor pressure ({approx}5x10{sup 3} Pa) of water, microwave breakdown gives rise to plasmas in many bubbles in the boiling water. Gas bubbling technique enables production of multibubble plasmas in water even at atmospheric pressure. Optical emissions from the exited species are investigated to identify radical species in water. In order to demonstrate application to purification of polluted water, methylene blue and trichlorethylene solution in 8 l water were observed to rapidly decrease with multibubble plasma treatment.

  3. Bacterial communities associated with the decomposition of Fucus vesiculosus in transitional waters

    NASA Astrophysics Data System (ADS)

    Martins, Patrícia; Lopes, Marta Lobão; Rodrigues, Ana Maria; Gomes, Newton C. M.; Quintino, Victor

    2012-09-01

    In this work we study the temporal and spatial patterns of the bacterial communities associated with the decomposition of Fucus vesiculosus and a control substrate in a transitional ecosystem. Leaf-bags with 5 mm mesh-size and containing the experimental substrates were placed in three areas, euhaline, mesohaline and limnetic, covering the full salinity gradient. The substrates were submerged at day 0 and three replicates were randomly collected per site, at days 3, 7, 15, 30 and 60. The complexity and structural changes of the bacterial communities inhabiting F. vesiculosus and the control substrates were assessed by denaturing gradient gel electrophoresis (DGGE). Bacterial community fingerprints showed no significant differences between areas only at day 3, for both substrates. The bacterial community associated with F. vesiculosus showed significant differences over time in the euhaline and mesohaline areas but not in the limnetic area. A different trend was observed for the artificial substrate. Comparing the bacterial communities of F. vesiculosus and the artificial substrate, the results indicated that the significant differences between the two substrates were detected from day 7 in the euhaline area and only later, at day 15, in the other areas. These results are coherent with the fastest decomposition rate of the alga in the euhaline area, where it occurs naturally, and the slowest in the limnetic area, where it does not naturally exists.

  4. Survey of Microbial Enzymes in Soil, Water, and Plant Microenvironments

    PubMed Central

    Alves, Priscila Divina Diniz; Siqueira, Flávia de Faria; Facchin, Susanne; Horta, Carolina Campolina Rebello; Victória, Júnia Maria Netto; Kalapothakis, Evanguedes

    2014-01-01

    Detection of microbial enzymes in natural environments is important to understand biochemical activities and to verify the biotechnological potential of the microorganisms. In the present report, 346 isolates from soil, water, and plants were screened for enzyme production (caseinase, gelatinase, amylase, carboxymethyl cellulase, and esterase). Our results showed that 89.6% of isolates produced at least one tested enzyme. A predominance of amylase in soil samples, carboxymethyl cellulase in plants, as well as esterase and gelatinase in water was observed. Interesting enzymatic profiles were found in some microenvironments, suggesting specificity of available nutrients and/or natural selection. This study revealed the potential of microorganisms present in water, soil, and plant to produce important enzymes for biotechnological exploration. A predominance of certain enzymes was found, depending on the type of environmental sample. The distribution of microbial enzymes in soil, water and plants has been little exploited in previous reports. PMID:24847390

  5. Water Pinch Success Story at Solutia's Krummrich Plant 

    E-print Network

    Kumana, J. D.

    2000-01-01

    A site-wide water conservation and wastewater minimization study complementing the previous energy study was undertaken by a consulting engineering company specializing in Pinch Analysis for Solutia’s W.G. Krummrich plant in Sauget, Illinois...

  6. COMPUTER COST MODELS FOR POTABLE WATER TREATMENT PLANTS

    EPA Science Inventory

    A series of computer programs have been developed which calculate costs for specific unit treatment processes used in water treatment plants. The programs contained in this report are as follows: chlorination, chlorine dioxide, ozone, and granular activated carbon adsorption. Tab...

  7. 1. VIEW OF THE WATER FILTRATION PLANT FROM THE ACCESS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. VIEW OF THE WATER FILTRATION PLANT FROM THE ACCESS ROAD, LOOKING NORTHWEST. - Tower Hill No. 2 Mine, Approximately 0.47 mile Southwest of intersection of Stone Church Road & Township Route 561, Hibbs, Fayette County, PA

  8. 3. INTERIOR OF THE WATER FILTRATION PLANT SHOWING REMAINS OF ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. INTERIOR OF THE WATER FILTRATION PLANT SHOWING REMAINS OF THE FILTRATION APPARATUS. - Tower Hill No. 2 Mine, Approximately 0.47 mile Southwest of intersection of Stone Church Road & Township Route 561, Hibbs, Fayette County, PA

  9. MICROORGANISMS AND HIGHER PLANTS FOR WASTE WATER TREATMENT

    EPA Science Inventory

    Batch experiments were conducted to compare the waste water treatment efficiencies of plant-free microbial filters with filters supporting the growth of reeds (Phragmites communis), cattail (Typha latifolia), rush (Juncus effusus), and bamboo (Bambusa multiplex). The experimental...

  10. A Greener Arctic: Vascular Plant Litter Input in Subarctic Peat Bogs Changes Soil Invertebrate Diets and Decomposition Patterns

    NASA Astrophysics Data System (ADS)

    Krab, E. J.; Berg, M. P.; Aerts, R.; van Logtestijn, R. S. P.; Cornelissen, H. H. C.

    2014-12-01

    Climate-change-induced trends towards shrub dominance in subarctic, moss-dominated peatlands will most likely have large effects on soil carbon (C) dynamics through an input of more easily decomposable litter. The mechanisms by which this increase in vascular litter input interacts with the abundance and diet-choice of the decomposer community to alter C-processing have, however, not yet been unraveled. We used a novel 13C tracer approach to link invertebrate species composition (Collembola), abundance and species-specific feeding behavior to C-processing of vascular and peat moss litters. We incubated different litter mixtures, 100% Sphagnum moss litter, 100% Betula leaf litter, and a 50/50 mixture of both, in mesocosms for 406 days. We revealed the transfer of C from the litters to the soil invertebrate species by 13C labeling of each of the litter types and assessed 13C signatures of the invertebrates Collembola species composition differed significantly between Sphagnum and Betula litter. Within the 'single type litter' mesocosms, Collembola species showed different 13C signatures, implying species-specific differences in diet choice. Surprisingly, the species composition and Collembola abundance changed relatively little as a consequence of Betula input to a Sphagnum based system. Their diet choice, however, changed drastically; species-specific differences in diet choice disappeared and approximately 67% of the food ingested by all Collembola originated from Betula litter. Furthermore, litter decomposition patterns corresponded to these findings; mass loss of Betula increased from 16.1% to 26.2% when decomposing in combination with Sphagnum, while Sphagnum decomposed even slower in combination with Betula litter (1.9%) than alone (4.7%). This study is the first to empirically show that collective diet shifts of the peatland decomposer community from mosses towards vascular plant litter may drive altered decomposition patterns. In addition, we showed that although species-specific differences in Collembola feeding behavior appear to exist, species are very plastic in their diet. This implies that changes in C turnover rates with vegetation shifts, might well be due to diet shifts of the present decomposer community rather than by changes in species composition.

  11. Oxidative decomposition of atrazine in water in the presence of hydrogen peroxide using an innovative microwave photochemical reactor.

    PubMed

    Chen, Huilun; Bramanti, Emilia; Longo, Iginio; Onor, Massimo; Ferrari, Carlo

    2011-02-28

    The simultaneous application of microwave (MW) power and UV light leads to improved results in photochemical processes. This study investigates the oxidative decomposition of atrazine in water using an innovative MW and UV photochemical reactor, which activates a chemical reaction with MW and UV radiation using an immersed source without the need for a MW oven. We investigated the influence of reaction parameters such as initial H(2)O(2) concentrations, reaction temperatures and applied MW power and identified the optimal conditions for the oxidative decomposition of atrazine. Atrazine was completely degraded by MW/UV/H(2)O(2) in a very short time (i.e. t(1/2) = 1.1 min for 20.8 mg/L in optimal conditions). From the kinetic study, the disappearance rate of atrazine can be expressed as dX/dt = k(PH)[M](0)(b-X)(1-X), where b ? [H(2)O(2)](0)/[M](0)+k(OH)[·OH]/k(PH)[M](0), and X is the atrazine conversion, which correlates well with the experimental data. The kinetic analysis also showed that an indirect reaction of atrazine with an OH radical is dominant at low concentrations of H(2)O(2) and a direct reaction of atrazine with H(2)O(2) is dominant when the concentration of H(2)O(2) is more than 200 mg/L. PMID:21232855

  12. Temporal Dynamics of Abiotic and Biotic Factors on Leaf Litter of Three Plant Species in Relation to Decomposition Rate along a Subalpine Elevation Gradient

    PubMed Central

    Zhu, Jianxiao; Yang, Wanqin; He, Xinhua

    2013-01-01

    Relationships between abiotic (soil temperature and number of freeze-thaw cycles) or biotic factors (chemical elements, microbial biomass, extracellular enzymes, and decomposer communities in litter) and litter decomposition rates were investigated over two years in subalpine forests close to the Qinghai-Tibet Plateau in China. Litterbags with senescent birch, fir, and spruce leaves were placed on the forest floor at 2,704 m, 3,023 m, 3,298 m, and 3,582 m elevation. Results showed that the decomposition rate positively correlated with soil mean temperature during the plant growing season, and with the number of soil freeze-thaw cycles during the winter. Concentrations of soluble nitrogen (N), phosphorus (P) and potassium (K) had positive effects but C:N and lignin:N ratios had negative effects on the decomposition rate (k), especially during the winter. Meanwhile, microbial biomass carbon (MBC), N (MBN), and P (MBP) were positively correlated with k values during the first growing season. These biotic factors accounted for 60.0% and 56.4% of the variation in decomposition rate during the winter and the growing season in the first year, respectively. Specifically, litter chemistry (C, N, P, K, lignin, C:N and lignin:N ratio) independently explained 29.6% and 13.3%, and the microbe-related factors (MBC, MBN, MBP, bacterial and fungal biomass, sucrase and ACP activity) explained 22.9% and 34.9% during the first winter and the first growing season, respectively. We conclude that frequent freeze-thaw cycles and litter chemical properties determine the winter decomposition while microbe-related factors play more important roles in determining decomposition in the subsequent growing season. PMID:23620803

  13. OZONATION AND BIOLOGICAL STABILITY OF WATER IN AN OPERATING WATER TREATMENT PLANT

    EPA Science Inventory

    Ozonation of drinking water may adversely affect the biological stability of the inished water. his study was designed assess the effect of ozone as a preoxidant on the nutrient status of water treated in a full-scale water treatment plant. he study was conducted over a ten week ...

  14. 7. ONE OF THREE CIRCULATING WATER PUMPS FOR STEAM PLANT, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. ONE OF THREE CIRCULATING WATER PUMPS FOR STEAM PLANT, LOCATED ON FIRST FLOOR UNDER TURBINE DECK. VIEW OF PUMP LOCATED FARTHEST NORTH. November 13, 1990 - Crosscut Steam Plant, North side Salt River near Mill Avenue & Washington Street, Tempe, Maricopa County, AZ

  15. Global distribution of plant-extractable water capacity of soil

    USGS Publications Warehouse

    Dunne, K.A.; Willmott, C.J.

    1996-01-01

    Plant-extractable water capacity of soil is the amount of water that can be extracted from the soil to fulfill evapotranspiration demands. It is often assumed to be spatially invariant in large-scale computations of the soil-water balance. Empirical evidence, however, suggests that this assumption is incorrect. In this paper, we estimate the global distribution of the plant-extractable water capacity of soil. A representative soil profile, characterized by horizon (layer) particle size data and thickness, was created for each soil unit mapped by FAO (Food and Agriculture Organization of the United Nations)/Unesco. Soil organic matter was estimated empirically from climate data. Plant rooting depths and ground coverages were obtained from a vegetation characteristic data set. At each 0.5?? ?? 0.5?? grid cell where vegetation is present, unit available water capacity (cm water per cm soil) was estimated from the sand, clay, and organic content of each profile horizon, and integrated over horizon thickness. Summation of the integrated values over the lesser of profile depth and root depth produced an estimate of the plant-extractable water capacity of soil. The global average of the estimated plant-extractable water capacities of soil is 8??6 cm (Greenland, Antarctica and bare soil areas excluded). Estimates are less than 5, 10 and 15 cm - over approximately 30, 60, and 89 per cent of the area, respectively. Estimates reflect the combined effects of soil texture, soil organic content, and plant root depth or profile depth. The most influential and uncertain parameter is the depth over which the plant-extractable water capacity of soil is computed, which is usually limited by root depth. Soil texture exerts a lesser, but still substantial, influence. Organic content, except where concentrations are very high, has relatively little effect.

  16. Optical fluorescence biosensor for plant water stress detection

    NASA Astrophysics Data System (ADS)

    Chong, Jenny P. C.; Liew, O. W.; Li, B. Q.; Asundi, A. K.

    2007-05-01

    Precision farming in arable agriculture and horticulture allows conservative use of resources that are applied according to plant needs. The growing concern for sustainability in crop production has accentuated the significance of our work to develop a rapid, sensitive and non-destructive spectroscopic method for real-time monitoring of plant water stress. Elucidation of crop water status before the onset of irreversible cellular damage is critical for effective water management to ensure maximum crop yield and profit margin. A two-component bio-sensing system comprising transgenic 'Indicator Plants' and a spectrometer-linked stereoscopic microscope was developed to detect early signs of water stress before the permanent wilting point is reached. The 'Indicator Plants' are transgenic Petunia hybrida genetically engineered with a drought-responsive promoter-linked enhanced green fluorescent protein marker gene (EGFP). No EGFP fluorescence was detected prior to induction of dehydration stress. Fluorescence emission intensity increased with dehydration period and was found mainly in the stems, leaf veins and leaf tips. While fluorescence emission above endogenous background was detectable after 2 hours of water stress treatment, the plants reached permanent wilting point after 6 hours, showing that our system was able to detect water stress prior to plant entry into the stage of irreversible damage. Future work will be geared towards overcoming biological and instrument-related difficulties encountered in our initial detection system.

  17. Investigation of the loss mechanisms of hydroxyl radicals in the decomposition of organic compounds using plasma generated over water

    NASA Astrophysics Data System (ADS)

    Takeuchi, Nozomi; Ando, Mizuki; Yasuoka, Koichi

    2015-11-01

    Many types of plasma processes have been investigated as potential agents for decomposing persistent organic compounds in water using hydroxyl radicals (•OH), and a wide range of energy efficiency in the reduction of total organic carbon (TOC) has been observed. In this study, loss mechanisms of •OH that limit the energy efficiency were investigated using a plasma generated over an acetic acid solution. Various experiments, including the analysis of the decomposition process, a parametric study, and a numerical simulation, revealed that there are two main loss mechanisms: (i) a self-quenching reaction that generates hydrogen peroxide (H2O2) and (ii) a reaction of •OH with H2O2 and hydroperoxyl radicals (HO2•). In the solution, •OH reacts with these scavengers rather than target compounds. A pulsed plasma with a low current density, low repetition rate, and short pulse duration can be utilized to achieve high efficiency.

  18. ARSENIC REMOVAL FROM DRINKING WATER BY IRON REMOVAL PLANTS

    EPA Science Inventory

    This report documents a long term performance study of two iron removal water treatment plants to remove arsenic from drinking water sources. Performance information was collected from one system located in midwest for one full year and at the second system located in the farwest...

  19. INORGANIC CHEMICAL CHARACTERIZATION OF WATER TREATMENT PLANT RESIDUALS

    EPA Science Inventory

    The study obtained field data on the inorganic contaminants and constituents in residuals produced by Water Treatment Plants (WTPs). Eight WTPs were studied based on treatment technology, contamination or suspected contamination of raw water, and efficiency in the removal of cont...

  20. Case history advanced coatings for water treatment plant components

    SciTech Connect

    Stephenson, L.D.; Kumar, A.

    2008-12-15

    Components of water treatment plants (WTPs) are susceptible to corrosion from constant immersion in water. A case history of corrosion and proximity to chlorine problems and their treatment at an Army WTP is presented. Solutions included using high micro-silica restoration mortar and advanced coal tar epoxy coatings.

  1. Plants for water recycling, oxygen regeneration and food production

    NASA Technical Reports Server (NTRS)

    Bubenheim, D. L.

    1991-01-01

    During long-duration space missions that require recycling and regeneration of life support materials the major human wastes to be converted to usable forms are CO2, hygiene water, urine and feces. A Controlled Ecological Life Support System (CELSS) relies on the air revitalization, water purification and food production capabilities of higher plants to rejuvenate human wastes and replenish the life support materials. The key processes in such a system are photosynthesis, whereby green plants utilize light energy to produce food and oxygen while removing CO2 from the atmosphere, and transpiration, the evaporation of water from the plant. CELSS research has emphasized the food production capacity and efforts to minimize the area/volume of higher plants required to satisfy all human life support needs. Plants are a dynamic system capable of being manipulated to favour the supply of individual products as desired. The size and energy required for a CELSS that provides virtually all human needs are determined by the food production capacity. Growing conditions maximizing food production do not maximize transpiration of water; conditions favoring transpiration and scaling to recycle only water significantly reduces the area, volume, and energy inputs per person. Likewise, system size can be adjusted to satisfy the air regeneration needs. Requirements of a waste management system supplying inputs to maintain maximum plant productivity are clear. The ability of plants to play an active role in waste processing and the consequence in terms of degraded plant performance are not well characterized. Plant-based life support systems represent the only potential for self sufficiency and food production in an extra-terrestrial habitat.

  2. Naegleria fowleri in cooling waters of power plants.

    PubMed

    Cerva, L; Kasprzak, W; Mazur, T

    1982-01-01

    Six strains of nonvirulent and three strains of virulent variants of Naegleria fowleri amoebae were isolated from the examined cooling water samples from 9 power plants. The virulent variants were obtained solely from effluents discharged from power plants with a closed-circuit cooling N. fowleri was not detected outside the reach of the thermal pollution. A disinfection of out-flowing cooling water seems to be an unnecessary investment in our climate. Warm discharge water should under no conditions be used directly for sports and recreational purposes. PMID:7119430

  3. Settlement of soil due to water uptake by plant roots

    NASA Astrophysics Data System (ADS)

    Mathur, Shashi

    1999-10-01

    The settlement of soil occurs whenever there is an increase in effective confining stress. The withdrawal of water by plant roots results in a change in water pressure and moisture content in the soil. The variation in the moisture content leads to a change in the effective stress that causes a decrease in porosity which eventually results in the settlement of soil. The driving force for the uptake of water by the roots is the difference in the plant water and soil water potential existing between the soil solution adjacent to the roots and the root xylem. In case of transpiring plants, this driving force is mainly due to the tension (negative pressure) produced in the roots. A finite element solution of the governing equation yields the variation of moisture content with depth and the total settlement of the soil column due to the extraction of water by the plant roots. The simulated results indicate the damaging situation due to changes in the soil moisture content on account of transpiring trees and plants grown around the perimeter of structures.

  4. DOSE CONTROLLER FOR AGUACLARA WATER TREATMENT PLANTS

    EPA Science Inventory

    The expected results include a proven design for a gravity powered dose controller that works for calcium hypochlorite or aluminum sulfate solutions. The dose controller will be coupled with plant flow rate measuring systems that have compatible relationships between flow rate...

  5. [Mercury dynamics of several plants collected from the water-level fluctuation zone of the Three Gorges Reservoir area during flooding and its impact on water body].

    PubMed

    Zhang, Xiang; Zhang, Cheng; Sun, Rong-guo; Wang, Ding-yong

    2014-12-01

    Submerged plants are a major source for the abnormal elevation of methylmercury in reservoir. Several specific plants (Echinochloa crusgalli, Cynodondactylon and Corn stover) were collected and inundated in a simulated aquatic environment in the laboratory for investigating the mercury (Hg) dynamics in plants and the release process into water, aiming to find out the properties of Hg dynamics of plants under inundation conditions and its impact on water body in the Water-Level Fluctuation Zone of the Three Gorges Reservoir Area. The results showed that the contents of total mercury in several plants were in the range of 9. 21-12.07 ng x g(-1), and the percentage content of methylmercury (MeHg) was about 1%-2%. The content of total mercury (THg) in plants gradually decreased, by 35.81%-55.96%, whereas that of the dissolved mercury (DHg) increased sharply, by 103.23% -232.15%, which indicated an emission of Hg from plants to water in the process of decomposition. Furthermore, the state of inundation provided sufficient conditions for the methylation process in plants and therefore caused an increase of the content of methylmercury in the plant residues, which was 3.04-6.63 times as much as the initial content. The concentration of dissolved methylmercury (DMeHg) in the overlying water also increased significantly by 14.84- 16.05 times compared with the initial concentration. Meanwhile, the concentration of dissolved oxygen (DO) in the overlying water was significantly and negatively correlated with DMeHg. On the other hand, the concentration of dissolved organic carbon (DOC) in the overlying water was significantly and positively correlated with DMeHg. During the whole inundation period, the increase of DHg in the overlying water accounted for 41.74% -47.01% of the total amount of THg emission, and there was a negative correlation between the content of THg in plant residues and that of DHg in the overlying water. PMID:25826925

  6. USE of mine pool water for power plant cooling.

    SciTech Connect

    Veil, J. A.; Kupar, J. M .; Puder, M. G.

    2006-11-27

    Water and energy production issues intersect in numerous ways. Water is produced along with oil and gas, water runs off of or accumulates in coal mines, and water is needed to operate steam electric power plants and hydropower generating facilities. However, water and energy are often not in the proper balance. For example, even if water is available in sufficient quantities, it may not have the physical and chemical characteristics suitable for energy or other uses. This report provides preliminary information about an opportunity to reuse an overabundant water source--ground water accumulated in underground coal mines--for cooling and process water in electric generating facilities. The report was funded by the U.S. Department of Energy's (DOE's) National Energy Technology Laboratory (NETL), which has implemented a water/energy research program (Feeley and Ramezan 2003). Among the topics studied under that program is the availability and use of ''non-traditional sources'' of water for use at power plants. This report supports NETL's water/energy research program.

  7. Water vulnerabilities for existing coal-fired power plants.

    SciTech Connect

    Elcock, D.; Kuiper, J.; Environmental Science Division

    2010-08-19

    This report was funded by the U.S. Department of Energy's (DOE's) National Energy Technology Laboratory (NETL) Existing Plants Research Program, which has an energy-water research effort that focuses on water use at power plants. This study complements the Existing Plants Research Program's overall research effort by evaluating water issues that could impact power plants. Water consumption by all users in the United States over the 2005-2030 time period is projected to increase by about 7% (from about 108 billion gallons per day [bgd] to about 115 bgd) (Elcock 2010). By contrast, water consumption by coal-fired power plants over this period is projected to increase by about 21% (from about 2.4 to about 2.9 bgd) (NETL 2009b). The high projected demand for water by power plants, which is expected to increase even further as carbon-capture equipment is installed, combined with decreasing freshwater supplies in many areas, suggests that certain coal-fired plants may be particularly vulnerable to potential water demand-supply conflicts. If not addressed, these conflicts could limit power generation and lead to power disruptions or increased consumer costs. The identification of existing coal-fired plants that are vulnerable to water demand and supply concerns, along with an analysis of information about their cooling systems and related characteristics, provides information to help focus future research and development (R&D) efforts to help ensure that coal-fired generation demands are met in a cost-effective manner that supports sustainable water use. This study identified coal-fired power plants that are considered vulnerable to water demand and supply issues by using a geographical information system (GIS) that facilitated the analysis of plant-specific data for more than 500 plants in the NETL's Coal Power Plant Database (CPPDB) (NETL 2007a) simultaneously with 18 indicators of water demand and supply. Two types of demand indicators were evaluated. The first type consisted of geographical areas where specific conditions can generate demand vulnerabilities. These conditions include high projected future water consumption by thermoelectric power plants, high projected future water consumption by all users, high rates of water withdrawal per square mile (mi{sup 2}), high projected population increases, and areas projected to be in a water crisis or conflict by 2025. The second type of demand indicator was plant specific. These indicators were developed for each plant and include annual water consumption and withdrawal rates and intensities, net annual power generation, and carbon dioxide (CO{sub 2}) emissions. The supply indictors, which are also area based, include areas with low precipitation, high temperatures, low streamflow, and drought. The indicator data, which were in various formats (e.g., maps, tables, raw numbers) were converted to a GIS format and stored, along with the individual plant data from the CPPDB, in a single GIS database. The GIS database allowed the indicator data and plant data to be analyzed and visualized in any combination. To determine the extent to which a plant would be considered 'vulnerable' to a given demand or supply concern (i.e., that the plant's operations could be affected by water shortages represented by a potential demand or supply indicator), criteria were developed to categorize vulnerability according to one of three types: major, moderate, or not vulnerable. Plants with at least two major demand indicator values and/or at least four moderate demand indicator values were considered vulnerable to demand concerns. By using this approach, 144 plants were identified as being subject to demand concerns only. Plants with at least one major supply indicator value and/or at least two moderate supply indicator values were considered vulnerable to supply concerns. By using this approach, 64 plants were identified as being subject to supply concerns only. In addition, 139 plants were identified as subject to both demand and supply concerns. Therefore, a total of 347 plants were considere

  8. Stochastic Dynamics of Plant-Water Interactions

    E-print Network

    Oren, Ram

    University, Durham, North Carolina 27708-0328; email: gaby@duke.edu Annu. Rev. Ecol. Evol. Syst. 2007. 38:767-water interactions. 767 Annu.Rev.Ecol.Evol.Syst.2007.38:767-791.Downloadedfromarjournals.annualreviews.org by

  9. Dynamics of phosphorus-iron-sulfur at the sediment-water interface influenced by algae blooms decomposition.

    PubMed

    Han, Chao; Ding, Shiming; Yao, Lei; Shen, Qiushi; Zhu, Chungang; Wang, Yan; Xu, Di

    2015-12-30

    This study addresses the previously unknown effects of algae blooms on the dynamics of phosphorus (P), iron (Fe) and sulfur (S) across a lacustrine sediment-water interface (SWI). A mesocosm experiment was conducted in-situ to investigate these effects based on two recently-developed diffusive gradients in thin-films techniques (DGT). Soluble P, Fe(II), and S(-II) exhibited similar changing trends in a water column subject to the algae addition. Peak concentrations appeared on day 7 of the 16-day experiment. The lowest Eh occurred at the experiment's midway point indicating a strong algae degradation. A maximum increase in DGT-labile S appeared on day 8 near the SWI, while the DGT-labile P and Fe exhibited persistent increases almost to the end of experiment. Significantly positive correlations of labile P were observed switching from between labile Fe and labile S in sediments, suggesting a significant change in original Fe-coupled dynamics of P under algae decomposition. Apparent fluxes were calculated based on DGT profiles where a simultaneous release of P and S occurred from degraded algae, resulting in bidirectional diffusion fluxes from sediment to overlying water. In contrast, sediment acted as a major source of labile Fe due to added depth and apparently positive fluxes. PMID:26207579

  10. An index for plant water deficit based on root-weighted soil water content

    NASA Astrophysics Data System (ADS)

    Shi, Jianchu; Li, Sen; Zuo, Qiang; Ben-Gal, Alon

    2015-03-01

    Governed by atmospheric demand, soil water conditions and plant characteristics, plant water status is dynamic, complex, and fundamental to efficient agricultural water management. To explore a centralized signal for the evaluation of plant water status based on soil water status, two greenhouse experiments investigating the effect of the relative distribution between soil water and roots on wheat and rice were conducted. Due to the significant offset between the distributions of soil water and roots, wheat receiving subsurface irrigation suffered more from drought than wheat under surface irrigation, even when the arithmetic averaged soil water content (SWC) in the root zone was higher. A significant relationship was found between the plant water deficit index (PWDI) and the root-weighted (rather than the arithmetic) average SWC over root zone. The traditional soil-based approach for the estimation of PWDI was improved by replacing the arithmetic averaged SWC with the root-weighted SWC to take the effect of the relative distribution between soil water and roots into consideration. These results should be beneficial for scheduling irrigation, as well as for evaluating plant water consumption and root density profile.

  11. Water relations of riparian plants from warm desert regions

    USGS Publications Warehouse

    Smith, S.D.; Devitt, Dale A.; Cleverly, James R.; Busch, David E.

    1998-01-01

    Riparian plants have been classified as 'drought avoiders' due to their access to an abundant subsurface water supply. Recent water-relations research that tracks water sources of riparian plants using the stable isotopes of water suggests that many plants of the riparian zone use ground water rather than stream water, and not all riparian plants are obligate phreatophytes (dependent on ground water as a moisture source) but may occasionally be dependent of unsaturated soil moisture sources. A more thorough understanding of riparian plant-water relations must include water-source dynamics and how those dynamics vary over both space and time. Many rivers in the desert Southwest have been invaded by the exotic shrub Tamarix ramosissima (saltcedar). Our studies of Tamarix invasion into habitats formerly dominated by native riparian forests of primarily Populus and Salix have shown that Tamarix successfully invades these habitats because of its (1) greater tolerance to water stress and salinity, (2) status as a facultative, rather than obligate, phreatophyte and, therefore, its ability to recover from droughts and periods of ground-water drawdown, and (3) superior regrowth after fire. Analysis of water- loss rates indicate that Tamarix-dominated stands can have extremely high evapotranspiration rates when water tables are high but not necessarily when water tables are lower. Tamarix has leaf-level transpiration rates that are comparable to native species, whereas sap-flow rates per unit sapwood area are higher than in natives, suggesting that Tamarix maintains higher leaf area than can natives, probably due to its greater water stress tolerance. Tamarix desiccates and salinizes floodplains, due to its salt exudation and high transpiration rates, and may also accelerate fire cycles, thus predisposing these ecosystems to further loss of native taxa. Riparian species on regulated rivers can be exposed to seasonal water stress due to depression of floodplain water tables and elimination of annual floods. This can potentially result in a community shift toward more stress- tolerant taxa, such as Tamarix, due to the inability of other riparian species to germinate and establish in the desiccated floodplain environment. Management efforts aimed at maintaining native forests on regulated rivers and slowing the spread of Tamarix invasion must include at least partial reintroduction of historical flow regimes, which favor the recruitment of native riparian species and reverse long-term desiccation of desert floodplain environments.

  12. PHOTOREACTIVITY OF CHROMOPHORIC DISSOLVED ORGANIC MATTER (CDOM) DERIVED FROM DECOMPOSITION OF VARIOUS VASCULAR PLANT AND ALGAL SOURCES

    EPA Science Inventory

    Chromophoric dissolved organic matter (CDOM) in aquatic environments is derived from the microbial decomposition of terrestrial and microbial organic matter. Here we present results of studies of the spectral properties and photoreactivity of the CDOM derived from several organi...

  13. Plants Clean Air and Water for Indoor Environments

    NASA Technical Reports Server (NTRS)

    2007-01-01

    Wolverton Environmental Services Inc., founded by longtime government environmental scientist B.C. "Bill" Wolverton, is an environmental consulting firm that gives customers access to the results of his decades of cutting-edge bioremediation research. Findings about how to use plants to improve indoor air quality have been published in dozens of NASA technical papers and in the book, "How to Grow Fresh Air: 50 Houseplants That Purify Your Home or Office." The book has now been translated into 12 languages and has been on the shelves of bookstores for nearly 10 years. A companion book, "Growing Clean Water: Nature's Solution to Water Pollution," explains how plants can clean waste water. Other discoveries include that the more air that is allowed to circulate through the roots of the plants, the more effective they are at cleaning polluted air; and that plants play a psychological role in welfare in that people recover from illness faster in the presence of plants. Wolverton Environmental is also working in partnership with Syracuse University, to engineer systems consisting of modular wicking filters tied into duct work and water supplies, essentially tying plant-based filters into heating, ventilation, and air conditioning (HVAC) systems. Also, the company has recently begun to assess the ability of the EcoPlanter to remove formaldehyde from interior environments. Wolverton Environmental is also in talks with designers of the new Stennis Visitor's Center, who are interested in using its designs for indoor air-quality filters

  14. Strategies of Plant Water Use under Stochastic Hydrologic Conditions

    NASA Astrophysics Data System (ADS)

    Vico, G.; Albertson, J.; Katul, G.; Porporato, A.; Ridolfi, L.; Rodriguez-Iturbe, I.

    2003-12-01

    Recent papers on ecohydrology have discussed how a "tragedy of the commons" effect, in which the competitive evolutionary outcome is lower than the ecosystem optimum (e.g. maximum productivity), may arise in plants because of a trade-off between resource-uptake rate and resource efficiency. Using simple deterministic and stochastic models of soil water balance and ecosystem response to water stress, we investigate how efficient water-use strategies can evolve and persist against more aggressive but less efficient strategies of water use. Survival of plants and coexistence of different species is discussed in relation to their drought tolerance and water use efficiency, under conditions of temporal and spatial environmental variability

  15. Water use, productivity and interactions among desert plants

    SciTech Connect

    Ehleringer, J.R.

    1992-11-17

    Productivity, stability, and competitive interactions among ecosystem components within aridlands are key processes related directly to water in deserts. This project assumes that integrated aspects of plant metabolism provide insight into the structure and function of plant communities and ecosystems. While it is difficult to extrapolate from instantaneous physiological observations to higher scales, such as whole plant performance or to the interactions between plants as components of ecosystems, several key aspects of plant metabolism are scalable. Analyses of stable isotopic composition in plant tissues at natural abundance levels provide a useful tool that can provide insight into the consequences of physiological processes over temporal and spatial scales. Some plant processes continuously fractionate among light and heavy stable isotopic forms of an element; over time this results in integrated measures of plant metabolism. For example, carbon isotope fractionation during photosynthesis results in leaf carbon isotopic composition that is a measure of the set-point for photosynthetic metabolism and of water-use efficiency. Thus it provides information on the temporal scaling of a key physiological process.

  16. Water use, productivity and interactions among desert plants. Final report

    SciTech Connect

    Ehleringer, J.R.

    1992-11-17

    Productivity, stability, and competitive interactions among ecosystem components within aridlands are key processes related directly to water in deserts. This project assumes that integrated aspects of plant metabolism provide insight into the structure and function of plant communities and ecosystems. While it is difficult to extrapolate from instantaneous physiological observations to higher scales, such as whole plant performance or to the interactions between plants as components of ecosystems, several key aspects of plant metabolism are scalable. Analyses of stable isotopic composition in plant tissues at natural abundance levels provide a useful tool that can provide insight into the consequences of physiological processes over temporal and spatial scales. Some plant processes continuously fractionate among light and heavy stable isotopic forms of an element; over time this results in integrated measures of plant metabolism. For example, carbon isotope fractionation during photosynthesis results in leaf carbon isotopic composition that is a measure of the set-point for photosynthetic metabolism and of water-use efficiency. Thus it provides information on the temporal scaling of a key physiological process.

  17. The analysis and composition of fatty material produced by the decomposition of herring in sea water

    USGS Publications Warehouse

    Wells, R.C.; Erickson, E.T.

    1933-01-01

    This paper describes the analysis of calcium and magnesium salts of fatty acids derived from herring buried under sea water, and discusses some geochemical possibilities related to the origin of petroleum in sedimentary deposits.

  18. Optimal plant water-use strategies under stochastic rainfall

    NASA Astrophysics Data System (ADS)

    Manzoni, Stefano; Vico, Giulia; Katul, Gabriel; Palmroth, Sari; Porporato, Amilcare

    2014-07-01

    Plant hydraulic traits have been conjectured to be coordinated, thereby providing plants with a balanced hydraulic system that protects them from cavitation while allowing an efficient transport of water necessary for photosynthesis. In particular, observations suggest correlations between the water potentials at which xylem cavitation impairs water movement and the one at stomatal closure, and between maximum xylem and stomatal conductances, begging the question as to whether such coordination emerges as an optimal water-use strategy under unpredictable rainfall. Here mean transpiration is used as a proxy for long-term plant fitness and its variations as a function of the water potentials at 50% loss of stem conductivity due to cavitation and at 90% stomatal closure are explored. It is shown that coordination between these hydraulic traits is necessary to maximize , with rainfall patterns altering the optimal range of trait values. In contrast, coordination between ecosystem-level conductances appears not necessary to maximize . The optimal trait ranges are wider under drier than under mesic conditions, suggesting that in semiarid systems different water use strategies may be equally successful. Comparison with observations across species from a range of ecosystems confirms model predictions, indicating that the coordinated functioning of plant organs might indeed emerge from an optimal response to rainfall variability.

  19. Macroscopic modeling of plant water uptake: soil and root resistances

    NASA Astrophysics Data System (ADS)

    Vogel, Tomas; Votrubova, Jana; Dohnal, Michal; Dusek, Jaromir

    2014-05-01

    The macroscopic physically-based plant root water uptake (RWU) model, based on water-potential-gradient formulation (Vogel et al., 2013), was used to simulate the observed soil-plant-atmosphere interactions at a forest site located in a temperate humid climate of central Europe and to gain an improved insight into the mutual interplay of RWU parameters that affects the soil water distribution in the root zone. In the applied RWU model, the uptake rates are directly proportional to the potential gradient and indirectly proportional to the local soil and root resistances to water flow. The RWU algorithm is implemented in a one-dimensional dual-continuum model of soil water flow based on Richards' equation. The RWU model is defined by four parameters (root length density distribution, average active root radius, radial root resistance, and the threshold value of the root xylem potential). In addition, soil resistance to water extraction by roots is related to soil hydraulic conductivity function and actual soil water content. The RWU model is capable of simulating both the compensatory root water uptake, in situations when reduced uptake from dry layers is compensated by increased uptake from wetter layers, and the root-mediated hydraulic redistribution of soil water, contributing to more natural soil moisture distribution throughout the root zone. The present study focusses on the sensitivity analysis of the combined soil water flow and RWU model responses in respect to variations of RWU model parameters. Vogel T., M. Dohnal, J. Dusek, J. Votrubova, and M. Tesar. 2013. Macroscopic modeling of plant water uptake in a forest stand involving root-mediated soil-water redistribution. Vadose Zone Journal, 12, 10.2136/vzj2012.0154.

  20. Water Relations of Cotton Plants under Nitrogen Deficiency

    PubMed Central

    Radin, John W.; Parker, Linda L.

    1979-01-01

    Nitrogen deficiency in cotton plants (Gossypium hirsutum L.) considerably increased the sensitivity of stomata to water stress. At air temperatures of 27, 35, and ?40 C, threshold potentials for complete stomatal closure were ?10, ?15, and ?26 bars in N-deficient plants and ?20, ?20, and ?30 bars in high-N plants, respectively. This three-way interaction among N supply, water potential, and air temperature was similar to that exerted on leaf expansion. The effects of N supply on stomatal behavior could not be explained on the basis of either osmotic or structural considerations. Rather, effects of N deficiency on mesophyll and stomata were independent and divergent. Stomatal behavior may impart a stress avoidance type of drought resistance to N-deficient plants. Images PMID:16660997

  1. Computing Cylindrical Algebraic Decomposition via Triangular Decomposition

    E-print Network

    Moreno Maza, Marc

    Computing Cylindrical Algebraic Decomposition via Triangular Decomposition Changbo Chen, Marc Cylindrical algebraic decomposition (CAD) is a fundamental tool in real algebraic geometry. It was introduced polynomial arithmetic, being developed for triangular decompositions. #12;Cylindrical Algebraic Decomposition

  2. The effect of metal salts on the decomposition of sweet sorghum bagasse in flow-through liquid hot water.

    PubMed

    Yu, Qiang; Zhuang, Xinshu; Yuan, Zhenhong; Qi, Wei; Wang, Qiong; Tan, Xuesong

    2011-02-01

    The impact of the metal salts NaCl, KCl, CaCl(2), MgCl(2), FeCl(3), FeCl(2), and CuCl(2), particularly the latter, on the decomposition of hemicellulose and lignin from sweet sorghum bagasse in liquid hot water pretreatment processing was studied in an attempt to enhance the recovery of sugars. Transition metal chlorides significantly enhanced the hemicellulose removal compared to the alkaline earth metal chlorides and alkaline metal chlorides, contributing to the formation of a saccharide-metal cation intermediate complex. FeCl(2) greatly increased xylose degradation and about 60% xylan was converted into non-saccharide products. In contrast, an excellent total and monomeric xylose recovery was obtained after the CuCl(2) pretreatment. Most of the lignin was deposited on the surface of the residual solid with droplet morphologies after this pretreatment, and about 20% was degraded into monomeric products. The total recovery of sugars from sweet sorghum bagasse with 0.1% CuCl(2) solution pretreatment and 48 h enzymatic digestibility, reached 90.4%, which is superior to the recovery using hot water pretreatment only. PMID:21071212

  3. A molecular dynamics study of model SI clathrate hydrates: the effect of guest size and guest-water interaction on decomposition kinetics.

    PubMed

    Das, Subhadip; Baghel, Vikesh Singh; Roy, Sudip; Kumar, Rajnish

    2015-04-14

    One of the options suggested for methane recovery from natural gas hydrates is molecular replacement of methane by suitable guests like CO2 and N2. This approach has been found to be feasible through many experimental and molecular dynamics simulation studies. However, the long term stability of the resultant hydrate needs to be evaluated; the decomposition rate of these hydrates is expected to depend on the interaction between these guest and water molecules. In this work, molecular dynamics simulation has been performed to illustrate the effect of guest molecules with different sizes and interaction strengths with water on structure I (SI) hydrate decomposition and hence the stability. The van der Waals interaction between water of hydrate cages and guest molecules is defined by Lennard Jones potential parameters. A wide range of parameter spaces has been scanned by changing the guest molecules in the SI hydrate, which acts as a model gas for occupying the small and large cages of the SI hydrate. All atomistic simulation results show that the stability of the hydrate is sensitive to the size and interaction of the guest molecules with hydrate water. The increase in the interaction of guest molecules with water stabilizes the hydrate, which in turn shows a slower rate of hydrate decomposition. Similarly guest molecules with a reasonably small (similar to Helium) or large size increase the decomposition rate. The results were also analyzed by calculating the structural order parameter to understand the dynamics of crystal structure and correlated with the release rate of guest molecules from the solid hydrate phase. The results have been explained based on the calculation of potential energies felt by guest molecules in amorphous water, hydrate bulk and hydrate-water interface regions. PMID:25767053

  4. [Plant growth with limited water]. Performance report

    SciTech Connect

    Not Available

    1992-10-01

    When water is in short supply, soybean stem growth is inhibited by a physical limitation followed in a few hours by metabolic changes that reduce the extensibility of the cell walls. The extensibility then becomes the main limitation. With time, there is a modest recovery in extensibility along with an accumulation of a 28kD protein in the walls of the growth-affected cells. A 3lkD protein that was 80% similar in amino acid sequence also was present but did not accumulate in the walls of the stem cells. In the stem, growth was inhibited and the mRNA for the 28kD protein increased in response to water deprivation but the mRNA for the 3 1 kD protein did not. The roots continued to grow and the mRNA for the 28kD protein did not accumulate but the mRNA for the 3lkD protein did. Thus, there was a tissuespecific response of gene expression that correlated with the contrasting growth response to low water potential in the same seedlings. Further work using immunogold labeling, fluorescence labeling, and western blotting gave evidence that the 28kD protein is located in the cell wall as well as several compartments in the cytoplasm. Preliminary experiments indicate that the 28kD protein is a phosphatase.

  5. Do rock fragments participate to plant water and mineral nutrition?

    NASA Astrophysics Data System (ADS)

    Korboulewsky, Nathalie; Tétégan, Marion; Besnault, Adeline; Cousin, Isabelle

    2010-05-01

    Rock fragments modify soil properties, and can be a potential reservoir of water. Besides, recent studies showed that this coarse soil fraction is chemically active, release nutrients, and could therefore be involved in biogeochemical nutrient cycles. However, these studies carried out on rock fragments, crushed pebbles or mineral particles do not answer the question whether the coarse soil fraction has significant nutritive functions. Only a couple of studies were conducted on plants, one on grass and the other on coniferous seedlings. This present work attempted to assess if pebbles may act as water and nutrient sources for poplar saplings, a deciduous species. Remoulded soils were set up in 5 L-pots with three percentages of pebbles: 0, 20, and 40% in volume. We used, as substrate either fine earth or sand (quartz), and as rock fragments either calcareous or inert pebbles (quartz). Additional modalities were settled with sand mixed with 20 and 40% pebbles enriched with nutrients. Both fine earth and calcareous pebbles were collected from the Ap horizon of a calcareous lacustrine limestone silty soil located in the central region of France. After cleaning, all pebbles were mixed to reach a bulk density in pots of 1.1 g/cm3 for the fine earth and 1.5 g/cm3 for the sand. Ten replicates were settled per modality, and one cutting of Populus robusta was planted in each. The experiment was conducted under controlled conditions. All pots were saturated at the beginning of the experiment, then irrigated by capillarity and controlled to maintain a moderate water stress. Growth and evapotranspiration were followed regularly, while water stress status was measured by stomatal conductivity every day during two drying periods of 10 days. After three months, plants were collected, separated in below- and above-ground parts for biomass and cation analysis (Ca, Mg, K). Results showed that pebbles can participate to plant nutrition, but no reduction of water stress was observed. Indeed, plants' water stress increased along the drying periods but no significant difference of stomatal conductivity was measured between modalities. This indicates that water stored in the porosity of calcareous pebbles had no influence on the plant water status, suggesting that this reserve is either too low or not accessible for poplar saplings. Besides, the presence of pebbles reduced the growth (plant height and biomass), and even more the proportion of pebbles was high. This dilution effect was the main effect on plant development observed in this experiment. However at moderate pebbles proportion, mineralomass of plants grown with or without 20% calcareous pebbles were similar, and higher than that of modalities with quartz pebbles. In addition, plants had a biomass 16% higher when grown with calcareous pebbles than with quartz pebbles. These results indicate that plants access nutrients from pebbles and that growth conditions were significantly better in pots with calcareous compared to quartz pebbles at moderate proportion (20%). For modalities with 40% pebbles, no difference was found between calcareous and quartz pebbles when mixed with fine earth. However, plant biomass grown in sand were 2.5 to 3 times higher when mixed with 20 and 40% enriched pebbles respectively, than biomass of plants grown on sand only. These results suggest that plants access nutrients from pebbles, especially those adsorbed, but at higher proportion (40%) the detrimental effects of rock fragments (such as limitation of root development can mask their nutritional value. This study strengthen the hypothesis that coarse soil fraction may act as a nutrients source. The concept of an inert stone matrix that, from the plant point of view, only dilutes ecological functions of the soil, must be revised.

  6. Effect of Power Plant Cooling Water Discharge upon Water Quality in the Tokyo Bay

    NASA Astrophysics Data System (ADS)

    Kitahara, Kouichi; Wada, Akira; Uehara, Yoshikazu; Fukuoka, Ippei; Kawanaga, Mitsuhito; Takano, Tairyu

    Water quality in the Tokyo Bay is controlled by the load input from rivers, seawater currents, temperature variation, photosynthetic processes and others. On the other hand, 23.5 GJ/s of heat, as of 1995, is discharged into the Bay as cooling water effluent from thermal power plants along the coast. Low temperature water of bottom layers is pumped up and utilized as cooling water in thermal power plants. Although the intake and discharge of cooling water may influence water quality of coastal and inner bay areas where power plants are sited, few quantitative evaluations of the effects of cooling water on the water quality have been made yet. In the present study, we report a result of computations to predict the effects of cooling water discharge on the water quality of the Tokyo Bay in the summer, based on a "primary ecological model" for two thermal conditions: the current heat discharge of 23.5 GJ/s, and a heat discharge of 28.9 GJ/s which is expected in the future. Flow and water temperature distribution data, computed by Kitahara et al.(2003), were used to run the model. It was concluded that except in the vicinities of outlet points, water quality of the Tokyo Bay in the summer might be little changed by the future increase of 5.4 GJ/s of heat discharge.

  7. [Methods for determining plant water source in thin soil region: a review].

    PubMed

    Nie, Yun-peng; Chen, Hong-song; Wang, Ke-lin

    2010-09-01

    Plant water source depends on the distribution of available water in the environment, and the capability of plants in capturing water. In dry season, the soil water in thin soil region cannot satisfy the demand of normal plant growth, and whether the plants can use the water stored in weathered bedrock is the key for them to maintain their normal water consumption. This paper reviewed the research methods for determining the plant water source in thin soil region, including investigating and analyzing the characteristics of root growth and distribution, monitoring the changes of water content at various depths below ground surface, monitoring and analyzing the seasonal variation of plant water status, and identifying the plant water source by stable isotope techniques. The advantages and disadvantages of these methods and their potential applications in tracing plant water source in karst region of Southwest China were discussed. PMID:21265170

  8. [A field study of tundra plant litter decomposition rate via mass loss and carbon dioxide emission: the role of biotic and abiotic controls, biotope, season of year, and spatial-temporal scale].

    PubMed

    Pochikalov, A V; Karelin, D V

    2014-01-01

    Although many recently published original papers and reviews deal with plant matter decomposition rates and their controls, we are still very short in understanding of these processes in boreal and high latiude plant communities, especially in permafrost areas of our planet. First and foremost, this is holds true for winter period. Here, we present the results of 2-year field observations in south taiga and south shrub tundra ecosystems in European Russia. We pioneered in simultaneous application of two independent methods: classic mass loss estimation by litter-bag technique, and direct measurement of CO2 emission (respiration) of the same litter bags with different types of dead plant matter. Such an approach let us to reconstruct intra-seasonal dynamics of decomposition rates of the main tundra litter fractions with high temporal resolution, to estimate the partial role of different seasons and defragmentation in the process of plant matter decomposition, and to determine its factors under different temporal scale. PMID:25771676

  9. Effect of Electrolytes on the Decomposition of Dye by Pulsed Discharge in Air Spraying Water Droplets

    NASA Astrophysics Data System (ADS)

    Nose, Taisuke; Yokoyama, Yuzo; Minamitani, Yasushi

    Effect of electrolytes on the decolorization of indigo carmine and on the production of H2O2 by pulsed discharge in air spraying water droplets was performed in sodium chloride and magnesium sulfate solutions. Peak voltage of the discharge decreased with increasing solution conductivity, but peak current and discharge energy increased. Decolorization rate and decolorization efficiency of indigo carmine and the yield of H2O2 decreased with increasing chloride and sulfate ion concentrations. It was found that the decolorization of indigo carmine and the production of H2O2 are affected by the ion concentration even in the case of discharge in air spraying water droplets. However it was less effective than that of discharge in water. Chloride ion was more effective than sulfate ion regarding the decrease of decolorization rate and the production of H2O2. Decolorization rate of indigo carmine was strongly related to the production of H2O2. These results also indicated that decolorization of indigo carmine depends on the production of hydroxyl radical.

  10. Tragedy of the commons in plant water use

    NASA Astrophysics Data System (ADS)

    Zea-Cabrera, Eduardo; Iwasa, Yoh; Levin, Simon; RodríGuez-Iturbe, Ignacio

    2006-06-01

    In this paper we address the following question: how can efficient water use strategies evolve and persist when natural selection favors aggressive but inefficient individual water use? A tragedy of the commons, in which the competitive evolutionary outcome is lower than the ecosystem optimum (in this case defined as maximum productivity), arises because of (1) a trade-off between resource uptake rate and resource use efficiency and (2) the open access character of soil water as a resource. Competitive superiority is determined by the lowest value of the steady state soil moisture, which can be minimized by increasing water uptake or by increasing drought tolerance. When the competing types all have the same drought tolerance, the most aggressive water users exclude efficient ones, even though they produce a lower biomass when in monoculture. However, plants with low water uptake can exclude aggressive ones if they have enough drought tolerance to produce a lower steady state soil moisture. In that case the competitive superior is also the best monoculture, and there is no tragedy of the commons. Spatial segregation in soil moisture dynamics favors the persistence of conservative water use strategies and the evolution of lower maximum transpiration rates. Increasing genetic relatedness between competing plants favors the evolution of conservative water use strategies. Some combinations of soil moisture spatial segregation and intensity of kin selection may favor the evolution and maintenance of multiple types of plant water use. This occurs because a cyclical pattern of species replacement can arise where no single type can exclude all other types.

  11. STUDY OF MICROBIAL AEROSOLS EMITTED FROM A WATER RECLAMATION PLANT

    EPA Science Inventory

    The purpose of this investigation was to determine the occurrence of selected microorganisms in the air in the vicinity of the O'Hare Water Reclamation Plant (OWRP), Des Plaines, Illinois. The contribution of the OWRP to ambient microbial aerosols was determined by comparing base...

  12. SEMIPERMEABLE MEMBRANE SYSTEM FOR SUBJECTING PLANTS TO WATER STRESS

    EPA Science Inventory

    A system was evaluated for growing plants at reproducible levels of water stress. Beans (Phaseolus vulgaris L.) were grown in vermiculite, transferred to a semipermeable membrane system that encased the root vermiculate mass, and then placed into nutrient solutions to which vario...

  13. Classroom Techniques to Illustrate Water Transport in Plants

    ERIC Educational Resources Information Center

    Lakrim, Mohamed

    2013-01-01

    The transport of water in plants is among the most difficult and challenging concepts to explain to students. It is even more difficult for students enrolled in an introductory general biology course. An easy approach is needed to demonstrate this complex concept. I describe visual and pedagogical examples that can be performed quickly and easily…

  14. 2. VIEW OF THE WATER FILTRATION PLANT LOOKING SOUTHEAST. A ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. VIEW OF THE WATER FILTRATION PLANT LOOKING SOUTH-EAST. A SET OF FOUR EVENLY SPACED CONCRETE WALLS JUT OUT FROM THE NORTHEAST FACADE OF THE BUILDING. - Tower Hill No. 2 Mine, Approximately 0.47 mile Southwest of intersection of Stone Church Road & Township Route 561, Hibbs, Fayette County, PA

  15. Simulating Leaf Area of Corn Plants at Contrasting Water Status

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An exponential decay function was fitted with literature data to describe the decrease in leaf expansion rate as leaf water potential decreases. The fitted function was then applied to modify an existing leaf area simulation module in a soil-plant-atmosphere continuum model in order to simulate leaf...

  16. CHANGES IN MASS AND CHEMISTRY OF PLANT ROOTS DURING LONG-TERM DECOMPOSITION ON A CHIHUAHUAN DESERT WATERSHED

    EPA Science Inventory

    We studied the spatial and temporal patterns of decomposition of roots of a desert sub-shrub, a herbaceous annual, and four species of perennial grasses at several locations on nitrogen fertilized and unfertilized transects on a Chihuahuan Desert watershed for 3.5 years. There we...

  17. INFLUENCE OF DECOMPOSITION ON CHEMICAL PROPERTIES OF PLANT-AND MANURE-DERIVED DISSOLVED ORGANIC MATTER AND SORPTION TO GOETHITE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sorption of dissolved organic matter (DOM) plays an important role in maintaining the fertility and quality of soils in agricultural ecosystems. Few studies have examined the effects of decomposition on DOM sorption and chemical characteristics. This study investigated the sorption to goethite of ...

  18. Soil management systems to improve water availability for plants

    NASA Astrophysics Data System (ADS)

    Klik, A.; Rosner, J.

    2009-04-01

    Due to climate change it is expected that the air temperature will increase and the amount as well as the variability of rainfall will change drastically within this century. Higher temperatures and fewer rainy days with more extreme events will increase the risk of surface runoff and erosion. This will lead to reduced soil water storage and therefore to a lower water use efficiency of plants. Soil and land management systems need to be applied and adapted to improve the amount of water stored in the soil and to ensure crop productivity functions of soils under changing climatic conditions. In a 14-yr. long field experiment, the effects of three soil management systems have been studied at three sites in Austria with respect to surface runoff, soil erosion, losses of nutrients and pesticides. Eight years after beginning of the project soil samples have been taken from different depth throughout the root zone to investigate the effects on soil properties. The results show that soil management systems with reduced tillage intensity are able to improve infiltration and soil water storage. More soil water enables plant development during longer dry periods and decreases amounts of irrigation. Overall, the higher water retention in the landscape improves the regional water balance and reduces environmental problems like soil erosion and nutrient and pesticide losses

  19. The importance of nutritional regulation of plant water flux.

    PubMed

    Cramer, Michael D; Hawkins, Heidi-Jayne; Verboom, G Anthony

    2009-08-01

    Transpiration is generally considered a wasteful but unavoidable consequence of photosynthesis, occurring because water is lost when stomata open for CO(2) uptake. Additionally, transpiration has been ascribed the functions of cooling leaves, driving root to shoot xylem transport and mass flow of nutrients through the soil to the rhizosphere. As a consequence of the link between nutrient mass flow and transpiration, nutrient availability, particularly that of NO(3)(-), partially regulates plant water flux. Nutrient regulation of transpiration may function through the concerted regulation of: (1) root hydraulic conductance through control of aquaporins by NO(3)(-), (2) shoot stomatal conductance (g(s)) through NO production, and (3) pH and phytohormone regulation of g(s). These mechanisms result in biphasic responses of water flux to NO(3)(-) availability. The consequent trade-off between water and nutrient flux has important implications for understanding plant distributions, for production of water use-efficient crops and for understanding the consequences of global-change-linked CO(2) suppression of transpiration for plant nutrient acquisition. PMID:19449035

  20. Water Extraction from Coal-Fired Power Plant Flue Gas

    SciTech Connect

    Bruce C. Folkedahl; Greg F. Weber; Michael E. Collings

    2006-06-30

    The overall objective of this program was to develop a liquid disiccant-based flue gas dehydration process technology to reduce water consumption in coal-fired power plants. The specific objective of the program was to generate sufficient subscale test data and conceptual commercial power plant evaluations to assess process feasibility and merits for commercialization. Currently, coal-fired power plants require access to water sources outside the power plant for several aspects of their operation in addition to steam cycle condensation and process cooling needs. At the present time, there is no practiced method of extracting the usually abundant water found in the power plant stack gas. This project demonstrated the feasibility and merits of a liquid desiccant-based process that can efficiently and economically remove water vapor from the flue gas of fossil fuel-fired power plants to be recycled for in-plant use or exported for clean water conservation. After an extensive literature review, a survey of the available physical and chemical property information on desiccants in conjunction with a weighting scheme developed for this application, three desiccants were selected and tested in a bench-scale system at the Energy and Environmental Research Center (EERC). System performance at the bench scale aided in determining which desiccant was best suited for further evaluation. The results of the bench-scale tests along with further review of the available property data for each of the desiccants resulted in the selection of calcium chloride as the desiccant for testing at the pilot-scale level. Two weeks of testing utilizing natural gas in Test Series I and coal in Test Series II for production of flue gas was conducted with the liquid desiccant dehumidification system (LDDS) designed and built for this study. In general, it was found that the LDDS operated well and could be placed in an automode in which the process would operate with no operator intervention or adjustment. Water produced from this process should require little processing for use, depending on the end application. Test Series II water quality was not as good as that obtained in Test Series I; however, this was believed to be due to a system upset that contaminated the product water system during Test Series II. The amount of water that can be recovered from flue gas with the LDDS is a function of several variables, including desiccant temperature, L/G in the absorber, flash drum pressure, liquid-gas contact method, and desiccant concentration. Corrosion will be an issue with the use of calcium chloride as expected but can be largely mitigated through proper material selection. Integration of the LDDS with either low-grade waste heat and or ground-source heating and cooling can affect the parasitic power draw the LDDS will have on a power plant. Depending on the amount of water to be removed from the flue gas, the system can be designed with no parasitic power draw on the power plant other than pumping loads. This can be accomplished in one scenario by taking advantage of the heat of absorption and the heat of vaporization to provide the necessary temperature changes in the desiccant with the flue gas and precipitates that may form and how to handle them. These questions must be addressed in subsequent testing before scale-up of the process can be confidently completed.

  1. Plant Water Use Efficiency over Geological Time – Evolution of Leaf Stomata Configurations Affecting Plant Gas Exchange

    PubMed Central

    Assouline, Shmuel; Or, Dani

    2013-01-01

    Plant gas exchange is a key process shaping global hydrological and carbon cycles and is often characterized by plant water use efficiency (WUE - the ratio of CO2 gain to water vapor loss). Plant fossil record suggests that plant adaptation to changing atmospheric CO2 involved correlated evolution of stomata density (d) and size (s), and related maximal aperture, amax. We interpreted the fossil record of s and d correlated evolution during the Phanerozoic to quantify impacts on gas conductance affecting plant transpiration, E, and CO2 uptake, A, independently, and consequently, on plant WUE. A shift in stomata configuration from large s-low d to small s-high d in response to decreasing atmospheric CO2 resulted in large changes in plant gas exchange characteristics. The relationships between gas conductance, gws, A and E and maximal relative transpiring leaf area, (amax?d), exhibited hysteretic-like behavior. The new WUE trend derived from independent estimates of A and E differs from established WUE-CO2 trends for atmospheric CO2 concentrations exceeding 1,200 ppm. In contrast with a nearly-linear decrease in WUE with decreasing CO2 obtained by standard methods, the newly estimated WUE trend exhibits remarkably stable values for an extended geologic period during which atmospheric CO2 dropped from 3,500 to 1,200 ppm. Pending additional tests, the findings may affect projected impacts of increased atmospheric CO2 on components of the global hydrological cycle. PMID:23844085

  2. Interaction and photochemical decomposition of hydroperoxides at water ice surfaces and in bulk ice

    NASA Astrophysics Data System (ADS)

    Schrems, O.; Gand, M.; Ignatov, S. K.; Gadzhiev, O. B.; Cisami

    2011-12-01

    Hydroperoxides are important tropospheric trace gases as they are an important source of OH radicals. The simplest in this class is methyl hydroperoxide (CH3OOH) which is a product of methane oxidation by OH and HO2 radicals. Sinks of CH3OOH are photolysis, reactions with OH radicals or dry and wet deposition. Laboratory studies have shown that CH3OOH absorbs strongly over the region between 200 and 360 nm resulting in excitation to a dissociative electronic excited state. The pathway with the lowest threshold energy involves single bond cleavage giving rise to the CH3O + OH radical products. Our recent measurements at Neumayer station in Antarctica [1] have shown that CH3OOH mixing ratios during the polar day are considerably higher than during the polar night and correlate with UV radiation. Snow and ice-covered regions are huge sinks for tropospheric trace gases. For hydrogen peroxide and methyl hydroperoxide we have studied the low-temperature interaction of CH3OOH with the hexagonal water ice surface using DFT (BLYP/6-31++G(d,p) and B3LYP/6-311++G(2d,2p)) calculations [2, 3]. In these calculations we used the extended cluster models up to (H2O)48, (H2O)56, and (H2O)72 for the various modes of hydroperoxide coordination on different ice crystal planes and incorporation inside the ice [3]. Also, the effect of orientational isomerism of hydrogen bond network inside the water ice was investigated [2]. In laboratory experiments we have simulated the UV photochemistry of CH3OOH trapped in ice (H2O and D2O) at 14 K. The photoproducts (CH2O, HCO, CO, CO2) formed in the ice have been identified by means of FTIR spectroscopy. [1] Riedel K., Weller R., Schrems O., König-Langlo G., Atmos.Environ., 2000,34, 5225-5234. [2] Ignatov S.K., Razuvaev A.G., Sennikov P.G., Schrems O., J.Mol.Struct.(THEOCHEM), 2009, 908,47-54. [3] Ignatov S.K., Gadzhiev O.B., Kulikov M.Yu., Petrov A.I., Razuvaev A.G., Gand M., Feigin A.M., Schrems O., J.Phys.Chem.C, 2011, 115, 9081-9089.

  3. Lignocellulose decomposition by microbial secretions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Carbon storage in terrestrial ecosystems is contingent upon the natural resistance of plant cell wall polymers to rapid biological degradation. Nevertheless, certain microorganisms have evolved remarkable means to overcome this natural resistance. Lignocellulose decomposition by microorganisms com...

  4. Phase field modelling of spinodal decomposition in the oil/water/asphaltene system.

    PubMed

    Tóth, Gyula I; Kvamme, Bjørn

    2015-08-21

    In this paper the quantitative applicability of van der Sman/van der Graaf type Ginzburg-Landau theories of surfactant assisted phase separation [van der Sman et al., Rheol. Acta, 2006, 46, 3] is studied for real systems displaying high surfactant concentrations at the liquid-liquid interface. The model is applied for the water/heptane/asphaltene system (a model of heavy crude oil), for which recent molecular dynamics (MD) simulations provide microscopic data needed to calibrate the theory. A list of general requirements is set up first, which is then followed by analytical calculations of the equilibrium properties of the system, such as the equilibrium liquid densities, the adsorption isotherm and the interfacial tension. Based on the results of these calculations, the model parameters are then determined numerically, yielding a reasonable reproduction of the MD density profiles. The results of time-dependent simulations addressing the dynamical behaviour of the system will also be presented. It will be shown that the competition between the diffusion and hydrodynamic time scales can lead to the formation of an emulsion. We also address the main difficulties and limitations of the theory regarding quantitative modelling of surfactant assisted liquid phase separation. PMID:26185915

  5. Karst features and plant water sources in Yucatan, Mexico

    NASA Astrophysics Data System (ADS)

    Estrada-Medina, H.; Querejeta, I.; Allen, M.; Graham, R.; Jimenez-Osornio, J.

    2008-05-01

    Despite limited water storage capacity, shallow soils of northern Yucatan can support woody vegetation with large standing biomass under seasonally dry tropical climate. Our research on the naturally occurring concentration gradients in oxygen and hydrogen stable isotopes in soil, bedrock, groundwater and plant stem water has shown the ability of tree species to take up water stored in the upper few meters of the weathered limestone bedrock underlying the shallow soils. None of the six native tree species investigated relied heavily on groundwater during the dry season. All stem water isotope samples departed significantly from the local meteoric water line, thus indicating that all the tree species took up evaporatively enriched water from relatively shallow sources. This is likely the key adaptive feature allowing native tree species to endure the pronounced annual drought, survive and ultimately shape the structure of the forest. Two drought deciduous tree species took up most of their water from the 5-15cm thick soil layer, and another one relied mostly on water stored in sub-surface weathered bedrock layers (epikarst). Among the evergreen species, two used epikarst water, and another one used mostly soil water. Therefore, rooting depth and water extraction depth do not appear to be strongly associated with the evergreen or deciduous habit of tree species. While trees in this area grow over a permanent water table (9-20 m depth), pit excavation has shown that roots are largely restricted to the upper 2 m of the soil/bedrock profile. However, our latest findings show that a few roots of some species are able to reach the water table.

  6. INNOVATIVE FRESH WATER PRODUCTION PROCESS FOR FOSSIL FUEL PLANTS

    SciTech Connect

    James F. Klausner; Renwei Mei; Yi Li; Mohamed Darwish; Diego Acevedo; Jessica Knight

    2003-09-01

    This report describes the annual progress made in the development and analysis of a Diffusion Driven Desalination (DDD) system, which is powered by the waste heat from low pressure condensing steam in power plants. The desalination is driven by water vapor saturating dry air flowing through a diffusion tower. Liquid water is condensed out of the air/vapor mixture in a direct contact condenser. A thermodynamic analysis demonstrates that the DDD process can yield a fresh water production efficiency of 4.5% based on a feed water inlet temperature of only 50 C. An example is discussed in which the DDD process utilizes waste heat from a 100 MW steam power plant to produce 1.51 million gallons of fresh water per day. The main focus of the initial development of the desalination process has been on the diffusion tower. A detailed mathematical model for the diffusion tower has been described, and its numerical implementation has been used to characterize its performance and provide guidance for design. The analysis has been used to design a laboratory scale diffusion tower, which has been thoroughly instrumented to allow detailed measurements of heat and mass transfer coefficient, as well as fresh water production efficiency. The experimental facility has been described in detail.

  7. Application of 2D-Nonlinear Shallow Water Model of Tsunami by using Adomian Decomposition Method

    SciTech Connect

    Waewcharoen, Sribudh; Boonyapibanwong, Supachai; Koonprasert, Sanoe

    2008-09-01

    One of the most important questions in tsunami modeling is the estimation of tsunami run-up heights at different points along a coastline. Methods for numerical simulation of tsunami wave propagation in deep and shallow seas are well developed and have been widely used by many scientists (2001-2008). In this paper, we consider a two-dimensional nonlinear shallow water model of tsunami given by Tivon Jacobson is work [1]. u{sub t}+uu{sub x}+{nu}u{sub y} -c{sup 2}(h{sub x}+(h{sub b}){sub x}) {nu}{sub t}+u{nu}{sub x}+{nu}{nu}{sub y} = -c{sup 2}(h{sub y}+(h{sub b}){sub y}) h{sub t}+(hu){sub x}+(h{nu}){sub y} = 0 g-shore, h is surface elevation and s, t is time, u is velocity of cross-shore, {nu} is velocity of along-shore, h is surface elevation and h{sub b} is function of shore. This is a nondimensionalized model with the gravity g and constant reference depth H factored into c = {radical}(gH). We apply the Adomian Decompostion Method (ADM) to solve the tsunami model. This powerful method has been used to obtain explicit and numerical solutions of three types of diffusion-convection-reaction (DECR) equations. The ADM results for the tsunami model yield analytical solutions in terms of a rapidly convergent infinite power series. Symbolic computation, numerical results and graphs of solutions are obtained by Maple program.

  8. Mixing Effects of Understory Plant Litter on Decomposition and Nutrient Release of Tree Litter in Two Plantations in Northeast China

    PubMed Central

    Zhao, Lei; Hu, Ya-Lin; Lin, Gui-Gang; Gao, Yong-chao; Fang, Yun-Ting; Zeng, De-Hui

    2013-01-01

    Understory vegetation plays a crucial role in carbon and nutrient cycling in forest ecosystems; however, it is not clear how understory species affect tree litter decomposition and nutrient dynamics. In this study, we examined the impacts of understory litter on the decomposition and nutrient release of tree litter both in a pine (Pinus sylvestris var. mongolica) and a poplar (Populus × xiaozhuanica) plantation in Northeast China. Leaf litter of tree species, and senesced aboveground materials from two dominant understory species, Artemisia scoparia and Setaria viridis in the pine stand and Elymus villifer and A. sieversiana in the poplar stand, were collected. Mass loss and N and P fluxes of single-species litter and three-species mixtures in each of the two forests were quantified. Data from single-species litterbags were used to generate predicted mass loss and N and P fluxes for the mixed-species litterbags. In the mixture from the pine stand, the observed mass loss and N release did not differ from the predicted value, whereas the observed P release was greater than the predicted value. However, the presence of understory litter decelerated the mass loss and did not affect N and P releases from the pine litter. In the poplar stand, litter mixture presented a positive non-additive effect on litter mass loss and P release, but an addition effect on N release. The presence of understory species accelerated only N release of poplar litter. Moreover, the responses of mass loss and N and P releases of understory litter in the mixtures varied with species in both pine and poplar plantations. Our results suggest that the effects of understory species on tree litter decomposition vary with tree species, and also highlight the importance of understory species in litter decomposition and nutrient cycles in forest ecosystems. PMID:24143184

  9. Stochastic estimation of plant-available soil water under fluctuating water table depths

    NASA Astrophysics Data System (ADS)

    Or, Dani; Groeneveld, David P.

    1994-12-01

    Preservation of native valley-floor phreatophytes while pumping groundwater for export from Owens Valley, California, requires reliable predictions of plant water use. These predictions are compared with stored soil water within well field regions and serve as a basis for managing groundwater resources. Soil water measurement errors, variable recharge, unpredictable climatic conditions affecting plant water use, and modeling errors make soil water predictions uncertain and error-prone. We developed and tested a scheme based on soil water balance coupled with implementation of Kalman filtering (KF) for (1) providing physically based soil water storage predictions with prediction errors projected from the statistics of the various inputs, and (2) reducing the overall uncertainty in both estimates and predictions. The proposed KF-based scheme was tested using experimental data collected at a location on the Owens Valley floor where the water table was artificially lowered by groundwater pumping and later allowed to recover. Vegetation composition and per cent cover, climatic data, and soil water information were collected and used for developing a soil water balance. Predictions and updates of soil water storage under different types of vegetation were obtained for a period of 5 years. The main results show that: (1) the proposed predictive model provides reliable and resilient soil water estimates under a wide range of external conditions; (2) the predicted soil water storage and the error bounds provided by the model offer a realistic and rational basis for decisions such as when to curtail well field operation to ensure plant survival. The predictive model offers a practical means for accommodating simple aspects of spatial variability by considering the additional source of uncertainty as part of modeling or measurement uncertainty.

  10. Changes in water quality in the Owabi water treatment plant in Ghana

    NASA Astrophysics Data System (ADS)

    Akoto, Osei; Gyamfi, Opoku; Darko, Godfred; Barnes, Victor Rex

    2014-09-01

    The study was conducted on the status of the quality of water from the Owabi water treatment plant that supplies drinking water to Kumasi, a major city in Ghana, to ascertain the change in quality of water from source to point-of-use. Physico-chemical, bacteriological water quality parameters and trace metal concentration of water samples from five different treatment points from the Owabi water treatment plant were investigated. The raw water was moderately hard with high turbidity and colour that exceeds the WHO guideline limits. Nutrient concentrations were of the following order: NH3 < NO2 - < NO3 - < PO4 3- < SO4 2- and were all below WHO permissible level for drinking water in all the samples at different stages of treatment. Trace metal concentrations of the reservoir were all below WHO limit except chromium (0.06 mg/L) and copper (0.24 mg/L). The bacteriological study showed that the raw water had total coliform (1,766 cfu/100 mL) and faecal coliform (257 cfu/100 mL) that exceeded the WHO standard limits, rendering it unsafe for domestic purposes without treatment. Colour showed strong positive correlation with turbidity (r = 0.730), TSS (r ? 0.922) and alkalinity (0.564) significant at p < 0.01. The quality of the treated water indicates that colour, turbidity, Cr and Cu levels reduced and fall within the WHO permissible limit for drinking water. Treatment process at the water treatment plant is adjudged to be good.

  11. Water Treatment Pilot Plant Design Manual: Low Flow Conventional/Direct Filtration Water Treatment Plant for Drinking Water Treatment Studies

    EPA Science Inventory

    This manual highlights the project constraints and concerns, and includes detailed design calculations and system schematics. The plant is based on engineering design principles and practices, previous pilot plant design experiences, and professional experiences and may serve as ...

  12. Modeling plant competition for soil water balance in Water-limited Mediterranean Ecosystems

    NASA Astrophysics Data System (ADS)

    Cortis, C.; Montaldo, N.

    2009-12-01

    In heterogeneous ecosystems, such Mediterranean ecosystems, contrasting plant functional types (PFTs, e.g., grass and woody vegetation) compete for the water use. In these complex ecosystems current modeling approaches need to be improved due to a general lack of knowledge about the relationship between ET and the plant survival strategies for the different PFTs under water stress. Indeed, still unsolved questions are: how the PFTs (in particular the root systems) compete for the water use, the impact of this competition on the water balance terms, and the role of the soil type and soil depth in this competition. For this reasons an elaborated coupled Vegetation dynamic model (VDM) - land surface model (LSM) model able to also predict root distribution of competing plant systems is developed. The transport of vertical water flow in the unsaturated soil is modelled through a Richards’ equation based model. The water extraction (sink) term is considered as the root water uptake. Two VDMs predict vegetation dynamics, including spatial and temporal distribution/evolution of the root systems in the soil of two competing species (grass and woody vegetation). An innovative method for solving the unlinear system of predicting equations is proposed. The coupled model is able to predict soil and root water potential of the two competing plant species. The model is tested for the Orroli case study, situated in the mid-west of Sardinia within the Flumendosa river watershed. The site landscape is a mixture of Mediterranean patchy vegetation types: trees, including wild olives and coark oaks, different shrubs and herbaceous species. In particular two contrasting plant functional types (grass and woody vegetation) have been included. The model well predict the soil moisture and vegetation dynamics for the case study, and significantly different root potentials are predicted for the two PFTs, highlighting the root competition for the water use. The soil depth is low in the case study, while the Flumendosa basin is characterized by soils of different type and depth (more silty and deep nearly the river valley), such as typical in Mediterranean basins. A sensitivity analysis to the soil depth and soil type is performed for investigating their influences on the PFT dynamics and soil water balance. The influence of vegetation cover distribution of each plant type is also investigated. Results show that the plant compete differently according to site soil characteristics, and the impact of vegetation dynamics on the soil water balance terms is significant and cannot be neglected in current hydrological approaches.

  13. Modeling plant competition for water use in Water-limited Mediterranean Ecosystems

    NASA Astrophysics Data System (ADS)

    Cortis, C.; Montaldo, N.

    2009-04-01

    In heterogeneous ecosystems, such Mediterranean ecosystems, contrasting plant functional types (PFTs, e.g., grass and woody vegetation) compete for the water use. In these complex ecosystems current modeling approaches need to be improved due to a general lack of knowledge about the relationship between ET and the plant survival strategies for the different PFTs under water stress. Indeed, still unsolved questions are: how the PFTs (in particular the root systems) compete for the water use, the impact of this competition on the water balance terms, and the role of the soil type and soil depth in this competition. For this reasons an elaborated coupled Vegetation dynamic model (VDM) - land surface model (LSM) model able to also predict root distribution of competing plant systems is developed. The transport of vertical water flow in the unsaturated soil is modelled through a Richards' equation based model. The water extraction (sink) term is considered as the root water uptake. Two VDMs predict vegetation dynamics, including spatial and temporal distribution/evolution of the root systems in the soil of two competing species (grass and woody vegetation). An innovative method for solving the unlinear system of predicting equations is proposed. The coupled model is able to predict soil and root water potential of the two competing plant species. The model is tested for the Orroli case study, situated in the mid-west of Sardinia within the Flumendosa river watershed. The site landscape is a mixture of Mediterranean patchy vegetation types: trees, including wild olives and coark oaks, different shrubs and herbaceous species. In particular two contrasting plant functional types (grass and woody vegetation) have been included. The model well predict the soil moisture and vegetation dynamics for the case study, and significantly different root potentials are predicted for the two PFTs, highlighting the root competition for the water use. The soil depth is low in the case study, while the Flumendosa basin is characterized by soils of different type and depth (more silty and deep nearly the river valley), such as typical in Mediterranean basins. A sensitivity analysis to the soil depth and soil type is performed for investigating their influences on the PFT dynamics and soil water balance. The influence of vegetation cover distribution of each plant type is also investigated. Results show that the plant compete differently according to site soil characteristics, and the impact of vegetation dynamics on the soil water balance terms is significant and cannot be neglected in current hydrological approaches.

  14. Significance of Plant Root Microorganisms in Reclaiming Water in CELSS

    NASA Technical Reports Server (NTRS)

    Bubenheim, David L.; Greene, Catherine; Wignarajah, Kanapathipillai; Kliss, Mark H. (Technical Monitor)

    1996-01-01

    Since many microorganisms demonstrate the ability to quickly break down complex mixtures of waste and environmental contaminants, examining their potential use for water recycling in a closed environment is appealing. Water contributes approximately 90 percent of the life sustaining provisions in a human space habitat. Nearly half of the daily water requirements will be used for personal hygiene and dish washing. The primary contaminants of the used "gray" water will be the cleansing agents or soaps used to carry out these functions. Reclaiming water from the gray water waste streams is one goal of the NASA program, Controlled Ecological Life Support Systems (CELSS). The microorganisms of plane roots are well documented to be of a beneficial effect to promote plant growth. Most plants exhibit a range of bacteria and fungi which can be highly plant-specific. In our investigations with lettuce grown in hydroponic culture, we identified a microflora of normal rhizosphere. When the roots were exposed to an anionic surfactant, the species diversity changed, based on morphological characteristics, with the numbers of species being reduced from 7 to 2 after 48 hours of exposure. In addition, the species that became dominant in the presence of the anionic surfactant also demonstrated a dramatic increase in population density which corresponded to the degradation of the surfactant in the root zone. The potential for using these or other rhizosphere bacteria as a primary or secondary waste processor is promising, but a number of issues still warrant investigation; these include but are not limited to: (1) the full identification of the microbes, (2) the classes of surfactants the microbes will degrade, (3) the environmental conditions required for optimal processing efficiency and (4) the ability of transferring the microbes to a non-living solid matrix such as a bioreactor.

  15. 77 FR 3009 - Knowledge and Abilities Catalog for Nuclear Power Plant Operators: Advanced Boiling Water Reactors

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-20

    ... Knowledge and Abilities Catalog for Nuclear Power Plant Operators: Advanced Boiling Water Reactors AGENCY... and Abilities Catalog for Nuclear Power Plant Operators: Advanced Boiling Water Reactors.'' DATES... developed using this Catalog along with the Operator Licensing Examination Standards for Power...

  16. Plant Responses of Drip Irrigated Trees to Climate and Water Stress 

    E-print Network

    Punthakey, J. F.; McFarland, M. J.; Rodrigue, P. B.; Worthington, J. W.

    1982-01-01

    Past irrigation research has shown that peach (prunus persica) trees vary in their field response to water stress, and the degree of stress is a function of the plants' environment. Water deficits reduce plant growth and crop yields, therefore...

  17. INNOVATIVE FRESH WATER PRODUCTION PROCESS FOR FOSSIL FUEL PLANTS

    SciTech Connect

    James F. Klausner; Renwei Mei; Yi Li; Jessica Knight

    2004-09-01

    An innovative Diffusion Driven Desalination (DDD) process was recently described where evaporation of mineralized water is driven by diffusion within a packed bed. The energy source to drive the process is derived from low pressure condensing steam within the main condenser of a steam power generating plant. Since waste heat is used to drive the process, the main cost of fresh water production is attributed to the energy cost of pumping air and water through the packed bed. This report describes the annual progress made in the development and analysis of a Diffusion Driven Desalination (DDD) system. A combined thermodynamic and dynamic analysis demonstrates that the DDD process can yield a fresh water production of 1.03 million gallon/day by utilizing waste heat from a 100 MW steam power plant based on a condensing steam pressure of only 3'' Hg. Throughout the past year, the main focus of the desalination process has been on the diffusion tower and direct contact condenser. Detailed heat and mass transfer analyses required to size and analyze these heat and mass transfer devices are described. An experimental DDD facility has been fabricated, and temperature and humidity data have been collected over a range of flow and thermal conditions. The analyses agree quite well with the current data and the information available in the literature. Direct contact condensers with and without packing have been investigated. It has been experimentally observed that the fresh water production rate is significantly enhanced when packing is added to the direct contact condensers.

  18. Hot water geothermal development: opportunities and pilot plant results

    SciTech Connect

    Crane, G.K.

    1982-08-01

    It has been projected that up to 11,000 MW of geothermal electric capacity may be on line in the United States by the year 2000. The majority of this capacity will come from hot water geothermal plants, as dry steam resources are limited. Currently, no commercial hot water geothermal capacity exists in the U.S., although, substantial capacity does exist in other countries. Large hot, high temperature resources exist in Southern California's Imperial Valley. Early research work has led to the technical success of a 10 MW unit at Brawley, and to the construction of second generation pilot unit at the Salton Sea resource.

  19. Modeling Halophytic Plants in APEX for Sustainable Water and Agriculture

    NASA Astrophysics Data System (ADS)

    DeRuyter, T.; Saito, L.; Nowak, B.; Rossi, C.; Toderich, K.

    2013-12-01

    A major problem for irrigated agricultural production is soil salinization, which can occur naturally or can be human-induced. Human-induced, or secondary salinization, is particularly a problem in arid and semi-arid regions, especially in irrigated areas. Irrigated land has more than twice the production of rainfed land, and accounts for about one third of the world's food, but nearly 20% of irrigated lands are salt-affected. Many farmers worldwide currently seasonally leach their land to reduce the soil salt content. These practices, however, create further problems such as a raised groundwater table, and salt, fertilizer, and pesticide pollution of nearby lakes and groundwater. In Uzbekistan, a combination of these management practices and a propensity to cultivate 'thirsty' crops such as cotton has also contributed to the Aral Sea shrinking nearly 90% by volume since the 1950s. Most common agricultural crops are glycophytes that have reduced yields when subjected to salt-stress. Some plants, however, are known as halophytic or 'salt-loving' plants and are capable of completing their life-cycle in higher saline soil or water environments. Halophytes may be useful for human consumption, livestock fodder, or biofuel, and may also be able to reduce or maintain salt levels in soil and water. To assess the potential for these halophytes to assist with salinity management, we are developing a model that is capable of tracking salinity under different management practices in agricultural environments. This model is interdisciplinary as it combines fields such as plant ecology, hydrology, and soil science. The US Department of Agriculture (USDA) model, Agricultural Policy/Environmental Extender (APEX), is being augmented with a salinity module that tracks salinity as separate ions across the soil-plant-water interface. The halophytes Atriplex nitens, Climacoptera lanata, and Salicornia europaea are being parameterized and added into the APEX model database. Field sites in the Central Kyzylkum and Khorezm regions of Uzbekistan are being characterized in the model, where halophytes are being grown and plant, soil, and water data are being collected for model verification. This presentation will discuss the plant and site parameterizations as well as preliminary progress on developing and applying the APEX salinity module for modeling the salt cycle through soil, water, and halophytes under different management practices.

  20. Removal of fluoride contamination in water by three aquatic plants.

    PubMed

    Karmakar, Sukalpa; Mukherjee, Joydeep; Mukherjee, Somnath

    2016-03-01

    Phytoremediation, popularly known as 'green technology' has been employed in the present investigation to examine the potential of fluoride removal from water by some aquatic plants. Fluoride contamination in drinking water is very much prevalent in different parts of the world including India. Batch studies were conducted using some aquatic plants e.g., Pistia stratiotes, Eichhornia crassipes, and Spirodela polyrhiza which profusely grow in natural water bodies. The experimental data exhibited that all the above three aquatic floating macrophytes could remove fluoride to some relative degree of efficiency corresponding to initial concentration of fluoride 3, 5, 10, 20 mg/l after 10 days exposure time. Result showed that at lower concentration level i.e., 3 mg/L removal efficiency of Pistia stratiotes (19.87%) and Spirodela polyrhiza (19.23%) was found to be better as compared to Eichhornia crassipes (12.71%). Some of the physiological stress induced parameters such as chlorophyll a, chlorophyll b, total chlorophyll, carotenoid, total protein, catalase, and peroxidase were also studied to explore relative damage within the cell. A marginal stress was imparted among all the plants for lower concentration values (3 mg/L), whereas at 20 mg/l, maximum damage was observed. PMID:26247406

  1. ARSENIC REMOVAL FROM DRINKING WATER BY COAGULATION/FILTRATION AND LIME SOFTENING PLANTS

    EPA Science Inventory

    This report documents a long term performance (one year) study of 3 water treatment plants to remove arsenic from drinking water sources. The 3 plants consisted of 2 conventional coagulation/filtration plants and 1 lime softening plant. The study involved the collecting of weekly...

  2. El Paso landscape perspective: Researchers study water conservation, plant-tolerance, and water reuse 

    E-print Network

    Kalisek, Danielle

    2011-01-01

    Summer 2011 tx H2O 15 ] Story by Danielle Kalisek Dr. Genhua Niu of El Paso is identifying drought, salt, and heat-tolerant landscape plants more suitable for El Paso?s environment in her research. The hot, dry climate and saltier water... of El Paso can be a landscaper?s nightmare. But scientists at the Texas AgriLife Research and Extension Center at El Paso are researching plant and turf tolerance to be?er adapt to this climate and saline water situation. In addition, reclaimed...

  3. Foulant characteristics comparison in recycling cooling water system makeup by municipal reclaimed water and surface water in power plant.

    PubMed

    Ping, Xu; Jing, Wang; Yajun, Zhang; Jie, Wang; Shuai, Si

    2015-01-01

    Due to water shortage, municipal reclaimed water rather than surface water was replenished into recycling cooling water system in power plants in some cities in China. In order to understand the effects of the measure on carbon steel corrosion, characteristics of two kinds of foulant produced in different systems were studied in the paper. Differences between municipal reclaimed water and surface water were analyzed firstly. Then, the weight and the morphology of two kinds of foulant were compared. Moreover, other characteristics including the total number of bacteria, sulfate reducing bacteria, iron bacteria, extracellular polymeric substance (EPS), protein (PN), and polysaccharide (PS) in foulant were analyzed. Based on results, it could be concluded that microbial and corrosive risk would be increased when the system replenished by municipal reclaimed water instead of surface water. PMID:25893132

  4. Foulant Characteristics Comparison in Recycling Cooling Water System Makeup by Municipal Reclaimed Water and Surface Water in Power Plant

    PubMed Central

    Ping, Xu; Jing, Wang; Yajun, Zhang; Jie, Wang; Shuai, Si

    2015-01-01

    Due to water shortage, municipal reclaimed water rather than surface water was replenished into recycling cooling water system in power plants in some cities in China. In order to understand the effects of the measure on carbon steel corrosion, characteristics of two kinds of foulant produced in different systems were studied in the paper. Differences between municipal reclaimed water and surface water were analyzed firstly. Then, the weight and the morphology of two kinds of foulant were compared. Moreover, other characteristics including the total number of bacteria, sulfate reducing bacteria, iron bacteria, extracellular polymeric substance (EPS), protein (PN), and polysaccharide (PS) in foulant were analyzed. Based on results, it could be concluded that microbial and corrosive risk would be increased when the system replenished by municipal reclaimed water instead of surface water. PMID:25893132

  5. Soil Water Sensor Needs for the Evaluation of Hydraulic Lift in Crop Plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hydraulic lift (HL) in plants is defined as the process by which water is redistributed from wet soil zones to drier soil zones through the plant root system in response to gradients in water potential. Water is released into the dry soil when plant transpiration is low (night) and reabsorbed by th...

  6. 78 FR 35330 - Initial Test Programs for Water-Cooled Nuclear Power Plants

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-12

    ... COMMISSION Initial Test Programs for Water-Cooled Nuclear Power Plants AGENCY: Nuclear Regulatory Commission... revision to Regulatory Guide (RG), 1.68, ``Initial Test Programs for Water-Cooled Nuclear Power Plants... Initial Test Programs (ITPs) for light water cooled nuclear power plants. ADDRESSES: Please refer...

  7. Study of the dynamics of Zn, Fe, and Cu in the soil-plant system during leaf litter decomposition using isotopic compositions

    NASA Astrophysics Data System (ADS)

    Pichat, S.; Fekiacova, Z.

    2013-12-01

    Litter decomposition is a key process in the cycle of the elements in the soil-plant system. We have investigated the dynamics of three essential micronutrients (Zn, Fe, and Cu) in the vegetal cover, litter, organic horizons, and upper soil horizon (0-2 and 5-10 cm) using both element concentrations and isotopic compositions. The study was conducted on the O3HP (Oak Observatory at the Haute-Provence Observatory) experimental field site in southern France. O3HP is located far from pollution sources. It has been a fallow land for 70 years with the tree cover represented mainly by oak trees (Quercus pubescens). The soil is a thin layer of Calcisol developed under Mediterranean climate. The area has been subdivided in four zones as a function of plant cover. The results for two of these zones, dominated by respectively Poaceae and Genista hispanica, are reported here. We found that the concentrations of the three elements increase from the Ol to the Of horizon. Copper concentration in the Of horizon is close to that of the soil, whereas it is lower for Fe and Zn. For isotopic compositions, the behavior of the three elements is, however, different, which suggests different processes of redistribution for these elements. An enrichment in light Fe isotopes was observed from the Ol to the Of horizon, the latter having an isotopic composition similar to that of the soil. Zinc isotopic compositions are also similar in the Of horizon and the soil but they are isotopically heavier than in the Ol horizon. For Cu, the O horizons are isotopically heavier than the soil, with Of being the heaviest horizon. In addition, for Cu and Zn, the profiles in the O-horizons in the Poaceae-dominated and Genista hispanica-dominated areas are similar but their values are offset, suggesting an influence of the vegetal cover. The increase in concentration for Cu, Zn and Fe with age/depth in the O horizons is in agreement with what is commonly observed in litter-bag experiments, e.g. 1,2. Two mechanisms have been invoked to explain this phenomenon: 1) addition of metals by aerial dust and wet deposition or 2) absorption of metals from the soil by organisms that develop on the litter. Our vertical profiles of isotopic compositions in the O horizons show that the first hypothesis is unlikely. Instead, they suggest a downward transfer of isotopically light metals from the fresh litter to the base of the O horizon. In addition, the assumption of an upward transfer of isopically heavy Cu and Zn from the upper soil horizon to the Of horizon is needed to fully explain the profiles we observed. 1 Lomander and Johansson (2001) Water, Air, and Soil Pollut. 132, 165-184 2 Scheid et al. (2009) Eur. J. Soil Sci. 60, 613-621

  8. Innovative Fresh Water Production Process for Fossil Fuel Plants

    SciTech Connect

    James F. Klausner; Renwei Mei; Yi Li; Jessica Knight; Venugopal Jogi

    2005-09-01

    This project concerns a diffusion driven desalination (DDD) process where warm water is evaporated into a low humidity air stream, and the vapor is condensed out to produce distilled water. Although the process has a low fresh water to feed water conversion efficiency, it has been demonstrated that this process can potentially produce low cost distilled water when driven by low grade waste heat. This report describes the annual progress made in the development and analysis of a Diffusion Driven Desalination (DDD) system. A dynamic analysis of heat and mass transfer demonstrates that the DDD process can yield a fresh water production of 1.03 million gallon/day by utilizing waste heat from a 100 MW steam power plant based on a condensing steam pressure of only 3 Hg. The optimum operating condition for the DDD process with a high temperature of 50 C and sink temperature of 25 C has an air mass flux of 1.5 kg/m{sup 2}-s, air to feed water mass flow ratio of 1 in the diffusion tower, and a fresh water to air mass flow ratio of 2 in the condenser. Operating at these conditions yields a fresh water production efficiency (m{sub fW}/m{sub L}) of 0.031 and electric energy consumption rate of 0.0023 kW-hr/kg{sub fW}. Throughout the past year, the main focus of the desalination process has been on the direct contact condenser. Detailed heat and mass transfer analyses required to size and analyze these heat and mass transfer devices are described. The analyses agree quite well with the current data. Recently, it has been recognized that the fresh water production efficiency can be significantly enhanced with air heating. This type of configuration is well suited for power plants utilizing air-cooled condensers. The experimental DDD facility has been modified with an air heating section, and temperature and humidity data have been collected over a range of flow and thermal conditions. It has been experimentally observed that the fresh water production rate is enhanced when air is heated prior to entering the diffusion tower. Further analytical analysis is required to predict the thermal and mass transport with the air heating configuration.

  9. Biogeochemistry of Decomposition and Detrital Processing

    NASA Astrophysics Data System (ADS)

    Sanderman, J.; Amundson, R.

    2003-12-01

    Decomposition is a key ecological process that roughly balances net primary production in terrestrial ecosystems and is an essential process in resupplying nutrients to the plant community. Decomposition consists of three concurrent processes: communition or fragmentation, leaching of water-soluble compounds, and microbial catabolism. Decomposition can also be viewed as a sequential process, what Eijsackers and Zehnder (1990) compare to a Russian matriochka doll. Soil macrofauna fragment and partially solubilize plant residues, facilitating establishment of a community of decomposer microorganisms. This decomposer community will gradually shift as the most easily degraded plant compounds are utilized and the more recalcitrant materials begin to accumulate. Given enough time and the proper environmental conditions, most naturally occurring compounds can completely be mineralized to inorganic forms. Simultaneously with mineralization, the process of humification acts to transform a fraction of the plant residues into stable soil organic matter (SOM) or humus. For reference, Schlesinger (1990) estimated that only ˜0.7% of detritus eventually becomes stabilized into humus.Decomposition plays a key role in the cycling of most plant macro- and micronutrients and in the formation of humus. Figure 1 places the roles of detrital processing and mineralization within the context of the biogeochemical cycling of essential plant nutrients. Chapin (1991) found that while the atmosphere supplied 4% and mineral weathering supplied no nitrogen and <1% of phosphorus, internal nutrient recycling is the source for >95% of all the nitrogen and phosphorus uptake by tundra species in Barrow, Alaska. In a cool temperate forest, nutrient recycling accounted for 93%, 89%, 88%, and 65% of total sources for nitrogen, phosphorus, potassium, and calcium, respectively ( Chapin, 1991). (13K)Figure 1. A decomposition-centric biogeochemical model of nutrient cycling. Although there is significant external input (1) and output (2) from neighboring ecosystems (such as erosion), weathering of primary minerals (3), loss of secondary minerals (4), atmospheric deposition and N-fixation (5) and volatilization (6), the majority of plant-available nutrients are supplied by internal recycling through decomposition. Nutrients that are taken up by plants (7) are either consumed by fauna (8) and returned to the soil through defecation and mortality (10) or returned to the soil through litterfall and mortality (9). Detritus and humus can be immobilized into microbial biomass (11 and 13). Humus is formed by the transformation and stabilization of detrital (12) and microbial (14) compounds. During these transformations, SOM is being continually mineralized by the microorganisms (15) replenishing the inorganic nutrient pool (after Swift et al., 1979). The second major ecosystem role of decomposition is in the formation and stabilization of humus. The cycling and stabilization of SOM in the litter-soil system is presented in a conceptual model in Figure 2. Parallel with litterfall and most root turnover, detrital processing is concentrated at or near the soil surface. As labile SOM is preferentially degraded, there is a progressive shift from labile to passive SOM with increasing depth. There are three basic mechanisms for SOM accumulation in the mineral soil: bioturbation or physical mixing of the soil by burrowing animals (e.g., earthworms, gophers, etc.), in situ decomposition of roots and root exudates, and the leaching of soluble organic compounds. In the absence of bioturbation, distinct litter layers often accumulate above the mineral soil. In grasslands where the majority of net primary productivity (NPP) is allocated belowground, root inputs will dominate. In sandy soils with ample rainfall, leaching may be the major process incorporating carbon into the soil. (11K)Figure 2. Conceptual model of carbon cycling in the litter-soil system. In each horizon or depth increment, SOM is represented by three pools: labile SOM, slow SOM, and passive SOM. Inputs inc

  10. Stable isotopes in plant physiology: using water isotopes to study water fluxes in a temperate forest

    NASA Astrophysics Data System (ADS)

    Gerlein, C.; Wolf, A.; Caylor, K. K.

    2013-12-01

    Drought has profound consequences on vegetation, including decreases in instantaneous carbon uptake; damage that limits future uptake for the life of the plant; mortality that can lead to large sources of carbon to the atmosphere; and shifts in biogeography that alter future potential for carbon uptake and capacitance. These processes are largely absent from global models, for lack of understanding in how co-occurring plants compete for water, weak understanding of how plant hydraulics is coordinated to minimize risk of drought, and few empirical data to constrain superior models of these processes. Here we present the results of a large-scale field experiment at Silas Little Experimental Forest (NJ), where rainwater was diverted from a 10m^2 area around selected trees from two different species (either oak or pine trees) and either re-injected (control plots), discarded (drought plots) or replaced by isotopically labeled water (isotope plots). We sampled heavily the drought plots and collected valuable information on tree hydraulics under drought conditions, such as water potentials of soil, leaf and stem, photosynthetic rate or sap flow. At the isotope plots, we followed the injected water within the injection trees and the surrounding ones. In particular, using an innovative setup for in-situ measurement paired with a laser spectrometer, we studied the isotopes effects within the tree xylem, which gave us a better understanding of water uptake by the roots and its transport to the leaves. By tracking the labeled water in the surrounding trees, we were also able to quantify the importance of plant competition for water availability below ground. We show here the importance of understanding all the phases of the water transport in the biosphere to help constraining climate models.

  11. Ozone decomposition

    PubMed Central

    Batakliev, Todor; Georgiev, Vladimir; Anachkov, Metody; Rakovsky, Slavcho

    2014-01-01

    Catalytic ozone decomposition is of great significance because ozone is a toxic substance commonly found or generated in human environments (aircraft cabins, offices with photocopiers, laser printers, sterilizers). Considerable work has been done on ozone decomposition reported in the literature. This review provides a comprehensive summary of the literature, concentrating on analysis of the physico-chemical properties, synthesis and catalytic decomposition of ozone. This is supplemented by a review on kinetics and catalyst characterization which ties together the previously reported results. Noble metals and oxides of transition metals have been found to be the most active substances for ozone decomposition. The high price of precious metals stimulated the use of metal oxide catalysts and particularly the catalysts based on manganese oxide. It has been determined that the kinetics of ozone decomposition is of first order importance. A mechanism of the reaction of catalytic ozone decomposition is discussed, based on detailed spectroscopic investigations of the catalytic surface, showing the existence of peroxide and superoxide surface intermediates. PMID:26109880

  12. IMPACT OF PLANT DENSITY AND MICROBIAL COMPOSITION ON WATER QUALITY FROM A FREE WATER SURFACE CONSTRUCTED WETLAND

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aims: To determine the effects of plant density and microbial community composition associated with wetland plants from different wetland pond on water quality of a free water surface (FWS) constructed wetland. Methods & Results: Water chemistry was monitored weekly for nitrate, orthophosphate and s...

  13. Organic halogens in unpolluted waters and large bodies of water receiving bleach plant effluents

    SciTech Connect

    Grimvall, A.; Jonsson, S.; Karlsson, S.; Savenhed, R.; Boren, H. )

    1991-05-01

    In this paper the authors review and update recently performed studies of organic halogens in unpolluted waters and two large bodies of water receiving bleach plant effluents---Lake Vattern in Sweden and the Baltic Sea. All water samples contained measurable amounts of adsorbable organic halogens (AOX); the highest concentrations (up to 200 {mu}g Cl/L) were observed in humic lakes not exposed to any industrial discharges. Analysis of chlorophenols revealed that there is a long-distance transport ({gt} 100 km) of chloroguaiacols from bleach plants to remote parts of receiving waters. However, there was no evidence of chlorinated organics from bleach plants accumulating over several years in the water phase. One chlorophenol, 2,4,6-trichlorophenol, and its methylated analogue, 2,4,6-trichloroanisole, were also detected in surface waters considered to be unpolluted. Mass balance calculations showed that different processes in terrestrial environments make large contributions of AOX; enzyme-mediated chlorination of humic substances is a plausible explanation to the widespread occurrence of organic halogens.

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

    ERIC Educational Resources Information Center

    South Dakota Dept. of Environmental Protection, Pierre.

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

  15. Decomposition techniques

    USGS Publications Warehouse

    Chao, T.T.; Sanzolone, R.F.

    1992-01-01

    Sample decomposition is a fundamental and integral step in the procedure of geochemical analysis. It is often the limiting factor to sample throughput, especially with the recent application of the fast and modern multi-element measurement instrumentation. The complexity of geological materials makes it necessary to choose the sample decomposition technique that is compatible with the specific objective of the analysis. When selecting a decomposition technique, consideration should be given to the chemical and mineralogical characteristics of the sample, elements to be determined, precision and accuracy requirements, sample throughput, technical capability of personnel, and time constraints. This paper addresses these concerns and discusses the attributes and limitations of many techniques of sample decomposition along with examples of their application to geochemical analysis. The chemical properties of reagents as to their function as decomposition agents are also reviewed. The section on acid dissolution techniques addresses the various inorganic acids that are used individually or in combination in both open and closed systems. Fluxes used in sample fusion are discussed. The promising microwave-oven technology and the emerging field of automation are also examined. A section on applications highlights the use of decomposition techniques for the determination of Au, platinum group elements (PGEs), Hg, U, hydride-forming elements, rare earth elements (REEs), and multi-elements in geological materials. Partial dissolution techniques used for geochemical exploration which have been treated in detail elsewhere are not discussed here; nor are fire-assaying for noble metals and decomposition techniques for X-ray fluorescence or nuclear methods be discussed. ?? 1992.

  16. Seasonal Colonization and Decomposition of Rat Carrion in Water and on Land in an Open Field in South Carolina

    E-print Network

    Tomberlin, Jeff

    and colonization patterns ofcarrion in contrasting habitats, with important implications for forensic entomology. KEY WORDS carrion, decomposition, Calliphoridae, forensic entomology THE LARGE BODY of literature their usefulness in forensic entomology (Haskell et al. 1989, Keiper et al. 1997). Because most research

  17. 18 CFR 420.51 - Hydroelectric power plant water use charges.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    18 Conservation of Power and Water Resources 2 2013-04-01 2012-04-01 true Hydroelectric power plant water use charges. 420.51 Section 420.51 Conservation of Power and Water Resources DELAWARE RIVER BASIN...

  18. 18 CFR 420.51 - Hydroelectric power plant water use charges.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    18 Conservation of Power and Water Resources 2 2011-04-01 2011-04-01 false Hydroelectric power plant water use charges. 420.51 Section 420.51 Conservation of Power and Water Resources DELAWARE RIVER BASIN...

  19. 18 CFR 420.51 - Hydroelectric power plant water use charges.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    18 Conservation of Power and Water Resources 2 2012-04-01 2012-04-01 false Hydroelectric power plant water use charges. 420.51 Section 420.51 Conservation of Power and Water Resources DELAWARE RIVER BASIN...

  20. 18 CFR 420.51 - Hydroelectric power plant water use charges.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    18 Conservation of Power and Water Resources 2 2014-04-01 2014-04-01 false Hydroelectric power plant water use charges. 420.51 Section 420.51 Conservation of Power and Water Resources DELAWARE RIVER BASIN...

  1. 18 CFR 420.51 - Hydroelectric power plant water use charges.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    18 Conservation of Power and Water Resources 2 2010-04-01 2010-04-01 false Hydroelectric power plant water use charges. 420.51 Section 420.51 Conservation of Power and Water Resources DELAWARE RIVER BASIN...

  2. Evaluation of allelopathic, decomposition and cytogenetic activities of Jasminum officinale L. f. var. grandiflorum (L.) Kob. on bioassay plants.

    PubMed

    Teerarak, Montinee; Laosinwattana, Chamroon; Charoenying, Patchanee

    2010-07-01

    Methanolic extracts prepared from dried leaves of Jasminum officinale f. var. grandiflorum (L.) Kob. (Spanish jasmine) inhibited seed germination and stunted both root and shoot length of the weeds Echinochloa crus-galli (L.) Beauv. and Phaseolus lathyroides L. The main active compound was isolated and determined by spectral data as a secoiridoid glucoside named oleuropein. In addition, a decrease in allelopathic efficacy appeared as the decomposition periods increased. The mitotic index in treated onion root tips decreased with increasing concentrations of the extracts and longer periods of treatment. Likewise, the mitotic phase index was altered in onion incubated with crude extract. Furthermore, crude extract produced mitotic abnormalities resulting from its action on chromatin organization and mitotic spindle. PMID:20199861

  3. Life Cycle Assesment of Daugavgriva Waste Water Treatment Plant

    NASA Astrophysics Data System (ADS)

    Romagnoli, F.; Sampaio, F.; Blumberga, D.

    2009-01-01

    This paper presents the assessment of the environmental impacts caused by the treatment of Riga's waste water in the Daugavgriva plant with biogas energy cogeneration through the life cycle assessment (LCA). The LCA seems to be a good tool to assess and evaluate the most serious environmental impacts of a facility The results showed clearly that the impact category contributing the most to the total impact -eutrophicationcomes from the wastewater treatment stage. Climate change also seems to be a relevant impact coming from the wastewater treatment stage and the main contributor to the Climate change is N2O. The main environmental benefits, in terms of the percentages of the total impact, associated to the use of biogas instead of any other fossil fuel in the cogeneration plant are equal to: 3,11% for abiotic depletation, 1,48% for climate change, 0,51% for acidification and 0,12% for eutrophication.

  4. (Metabolic mechanisms of plant growth at low water potentials)

    SciTech Connect

    Not Available

    1990-01-01

    The work supported by DOE showed that water-limitation inhibits plant growth first by imposing a physical limitation that is followed in a few h by metabolic changes leading to reduced wall extensibility in the enlarging cells. After the wall extensibility decreased, a 28kD protein accumulated particularly in the walls of the growth-affected cells. Antibodies were used to identify cDNA for the protein. The base sequence of the cDNA was typical of an enzyme rather than known structural components of walls. The sequence was identical to one published by another laboratory at the same time and encoding a protein that accumulates in vacuoles of depodded soybean plants.

  5. The impact of water use fees on dispatching and water requirements for water-cooled power plants in Texas.

    PubMed

    Sanders, Kelly T; Blackhurst, Michael F; King, Carey W; Webber, Michael E

    2014-06-17

    We utilize a unit commitment and dispatch model to estimate how water use fees on power generators would affect dispatching and water requirements by the power sector in the Electric Reliability Council of Texas' (ERCOT) electric grid. Fees ranging from 10 to 1000 USD per acre-foot were separately applied to water withdrawals and consumption. Fees were chosen to be comparable in cost to a range of water supply projects proposed in the Texas Water Development Board's State Water Plan to meet demand through 2050. We found that these fees can reduce water withdrawals and consumption for cooling thermoelectric power plants in ERCOT by as much as 75% and 23%, respectively. To achieve these water savings, wholesale electricity generation costs might increase as much as 120% based on 2011 fuel costs and generation characteristics. We estimate that water saved through these fees is not as cost-effective as conventional long-term water supply projects. However, the electric grid offers short-term flexibility that conventional water supply projects do not. Furthermore, this manuscript discusses conditions under which the grid could be effective at "supplying" water, particularly during emergency drought conditions, by changing its operational conditions. PMID:24832169

  6. Rates of Litter Decomposition and Soil Respiration in Relation to Soil Temperature and Water in Different-Aged Pinus massoniana Forests in the Three Gorges Reservoir Area, China

    PubMed Central

    Zeng, Lixiong; Huang, Zhilin; Lei, Jingpin; Zhou, Benzhi; Li, Maihe

    2014-01-01

    To better understand the soil carbon dynamics and cycling in terrestrial ecosystems in response to environmental changes, we studied soil respiration, litter decomposition, and their relations to soil temperature and soil water content for 18-months (Aug. 2010–Jan. 2012) in three different-aged Pinus massoniana forests in the Three Gorges Reservoir Area, China. Across the experimental period, the mean total soil respiration and litter respiration were 1.94 and 0.81, 2.00 and 0.60, 2.19 and 0.71 µmol CO2 m?2 s?1, and the litter dry mass remaining was 57.6%, 56.2% and 61.3% in the 20-, 30-, and 46-year-old forests, respectively. We found that the temporal variations of soil respiration and litter decomposition rates can be well explained by soil temperature at 5 cm depth. Both the total soil respiration and litter respiration were significantly positively correlated with the litter decomposition rates. The mean contribution of the litter respiration to the total soil respiration was 31.0%–45.9% for the three different-aged forests. The present study found that the total soil respiration was not significantly affected by forest age when P. masonniana stands exceed a certain age (e.g. >20 years old), but it increased significantly with increased soil temperature. Hence, forest management strategies need to protect the understory vegetation to limit soil warming, in order to reduce the CO2 emission under the currently rapid global warming. The contribution of litter decomposition to the total soil respiration varies across spatial and temporal scales. This indicates the need for separate consideration of soil and litter respiration when assessing the climate impacts on forest carbon cycling. PMID:25004164

  7. Optimizing stomatal conductance for maximum carbon gain under water stress: a meta-analysis across plant

    E-print Network

    Oren, Ram

    Optimizing stomatal conductance for maximum carbon gain under water stress: a meta-analysis across atmospheric CO2, optimal water use, photosynthesis model, stomatal conductance, water stress, water use these risks, plants under water deficit reduce transpirational water losses by reducing stomatal conductance

  8. Has the plant genetic variability any role in models of water transfer in the soil-plant-atmosphere continuum ?

    NASA Astrophysics Data System (ADS)

    Tardieu, F.

    2012-04-01

    Water transfer in the SPAC is essentially linked to environmental conditions such as evaporative demand or soil water potential, and physical parameters such as soil hydraulic capacity or hydraulic conductivity. Models used in soil science most often represent the plant via a small number of variables such as the water flux that crosses the base of the stem or the root length (or area) in each soil layer. Because there is an increasing demand for computer simulations of plants that would perform better under water deficit, models of SPA water transfer are needed that could better take into account the genetic variability of traits involved in plant hydraulics. (i) The water flux through the plant is essentially limited by stomata, which present a much higher resistance to water flow than those in the soil - root continuum. This can lead to unexpected relations between flux, leaf water potential and root hydraulic conductance. (ii) A large genetic variability exists within and between species for stomatal control, with important consequences for the minimum soil water potential that is accessible to the plant. In particular, isohydric plants that maintain leaf water potential in a narrow range via stomatal control have a higher (nearer to 0) 'wilting point' than anisohydric plants that allow leaf water potential to reach very low values. (iii) The conductivity for water transfer in roots and shoots is controlled by plants via aquaporins. It largely varies with time of the day, water and nutrient status, in particular via plant hormones and circadian rhythms. Models of SPA water transfer with a time definition of minutes to hour should probably not ignore this, while those with longer time steps are probably less sensitive to changes in plant hydraulic conductivity. (iv) The "dogma" that dense root systems provide tolerance to water deficit is profoundly affected when the balance "H2O gain vs C investment" is taken into account. At least three programmes of recurrent selection for drought tolerance have resulted in a decrease in root biomass. Overall, it is now crucial to take into account the rapid progress in plant hydraulics in SPA models of water transfer. Several projects aim at this objective, in particular the EU project DROPS that gathers geneticists, plant modellers and soil modellers.

  9. Numerical simulation of the thermal conditions in a sea bay water area used for water supply to nuclear power plants

    SciTech Connect

    Sokolov, A. S.

    2013-07-15

    Consideration is given to the numerical simulation of the thermal conditions in sea water areas used for both water supply to and dissipation of low-grade heat from a nuclear power plant on the shore of a sea bay.

  10. Examples of Savannah River water dilution between the Savannah River Plant and the Beaufort-Jasper and Port Wentworth water-treatment plants

    SciTech Connect

    Hayes, D.W.

    1983-01-12

    A substantial dilution of the river water occurs between the Savannah River Plant (SRP) and the two treatment plants. This dilution results from inflow of surface and groundwater and from direct rainfall. The amount of dilution was estimated to be approximately 20% and 54% down to the Port Wentworth and Beaufort-Jasper plants, respectively.

  11. Nano-sized Mn3O4 and ?-MnOOH from the decomposition of ?-cyclodextrin-Mn: 2. The water-oxidizing activities.

    PubMed

    Najafpour, Mohammad Mahdi; Mostafalu, Ramin; Ho?y?ska, Ma?gorzata; Ebrahimi, Foad; Kaboudin, Babak

    2015-11-01

    Nano-sized Mn oxides contain Mn3O4, ?-MnOOH and Mn2O3 have been prepared by a previously reported method using thermal decomposition of ?-cyclodextrin-Mn complexes. In the next step, the water-oxidizing activities of these Mn oxides using cerium(IV) ammonium nitrate as a chemical oxidant are studied. The turnover frequencies for ?-MnO(OH) and Mn3O4 are 0.24 and 0.01-0.17 (mmol O2/mol Mns), respectively. Subsequently, water-oxidizing activities of these compounds are compared to the other previously reported Mn oxides. Important factors affecting water oxidation by these Mn oxides are also discussed. PMID:25779749

  12. Plants reverse warming effect on ecosystem water balance

    PubMed Central

    Zavaleta, Erika S.; Thomas, Brian D.; Chiariello, Nona R.; Asner, Gregory P.; Shaw, M. Rebecca; Field, Christopher B.

    2003-01-01

    Models predict that global warming may increase aridity in water-limited ecosystems by accelerating evapotranspiration. We show that interactions between warming and the dominant biota in a grassland ecosystem produced the reverse effect. In a 2-year field experiment, simulated warming increased spring soil moisture by 5–10% under both ambient and elevated CO2. Warming also accelerated the decline of canopy greenness (normalized difference vegetation index) each spring by 11–17% by inducing earlier plant senescence. Lower transpirational water losses resulting from this earlier senescence provide a mechanism for the unexpected rise in soil moisture. Our findings illustrate the potential for organism–environment interactions to modify the direction as well as the magnitude of global change effects on ecosystem functioning. PMID:12907704

  13. Effects of livestock watering sites on alien and native plants in the Mojave Desert, USA

    USGS Publications Warehouse

    Brooks, M.L.; Matchett, J.R.; Berry, K.H.

    2006-01-01

    Increased livestock densities near artificial watering sites create disturbance gradients called piospheres. We studied responses of alien and native annual plants and native perennial plants within 9 piospheres in the Mojave Desert of North America. Absolute and proportional cover of alien annual plants increased with proximity to watering sites, whereas cover and species richness of native annual plants decreased. Not all alien species responded the same, as the alien forb Erodium cicutarium and the alien grass Schismus spp. increased with proximity to watering sites, and the alien annual grass Bromus madritensis ssp. rubens decreased. Perennial plant cover and species richness also declined with proximity to watering sites, as did the structural diversity of perennial plant cover classes. Significant effects were focused within 200 m of the watering sites, suggesting that control efforts for alien annual plants and restoration efforts for native plants should optimally be focused within this central part of the piosphere gradient.

  14. A partition-limited model for the plant uptake of organic contaminants from soil and water

    USGS Publications Warehouse

    Chiou, C.T.; Sheng, G.; Manes, M.

    2001-01-01

    In dealing with the passive transport of organic contaminants from soils to plants (including crops), a partition-limited model is proposed in which (i) the maximum (equilibrium) concentration of a contaminant in any location in the plant is determined by partition equilibrium with its concentration in the soil interstitial water, which in turn is determined essentially by the concentration in the soil organic matter (SOM) and (ii) the extent of approach to partition equilibrium, as measured by the ratio of the contaminant concentrations in plant water and soil interstitial water, ??pt (??? 1), depends on the transport rate of the contaminant in soil water into the plant and the volume of soil water solution that is required for the plant contaminant level to reach equilibrium with the external soil-water phase. Through reasonable estimates of plant organic-water compositions and of contaminant partition coefficients with various plant components, the model accounts for calculated values of ??pt in several published crop-contamination studies, including near-equilibrium values (i.e., ??pt ??? 1) for relatively water-soluble contaminants and lower values for much less soluble contaminants; the differences are attributed to the much higher partition coefficients of the less soluble compounds between plant lipids and plant water, which necessitates much larger volumes of the plant water transport for achieving the equilibrium capacities. The model analysis indicates that for plants with high water contents the plant-water phase acts as the major reservoir for highly water-soluble contaminants. By contrast, the lipid in a plant, even at small amounts, is usually the major reservoir for highly water-insoluble contaminants.

  15. Biotic vs. abiotic control of decomposition: a comparison of the effects of simulated extinctions and changes in temperature.

    PubMed

    Boyero, Luz; Cardinale, Bradley J; Bastian, Mikis; Pearson, Richard G

    2014-01-01

    The loss of species is known to have significant effects on ecosystem functioning, but only recently has it been recognized that species loss might rival the effects of other forms of environmental change on ecosystem processes. There is a need for experimental studies that explicitly manipulate species richness and environmental factors concurrently to determine their relative impacts on key ecosystem processes such as plant litter decomposition. It is crucial to understand what factors affect the rate of plant litter decomposition and the relative magnitude of such effects because the rate at which plant litter is lost and transformed to other forms of organic and inorganic carbon determines the capacity for carbon storage in ecosystems and the rate at which greenhouse gasses such as carbon dioxide are outgassed. Here we compared how an increase in water temperature of 5°C and loss of detritivorous invertebrate and plant litter species affect decomposition rates in a laboratory experiment simulating stream conditions. Like some prior studies, we found that species identity, rather than species richness per se, is a key driver of decomposition, but additionally we showed that the loss of particular species can equal or exceed temperature change in its impact on decomposition. Our results indicate that the loss of particular species can be as important a driver of decomposition as substantial temperature change, but also that predicting the relative consequences of species loss and other forms of environmental change on decomposition requires knowledge of assemblages and their constituent species' ecology and ecophysiology. PMID:24466351

  16. Simulating Plant Water Stress and Phenology in Seasonally Dry Tropical Forests: Plant Hydraulics and Trait-Driven Trade-Offs

    NASA Astrophysics Data System (ADS)

    Xu, X.; Medvigy, D.; Powers, J. S.; Becknell, J. M.

    2014-12-01

    Seasonally dry tropical forests account for over 40% of the forested area in tropical and subtropical regions. Previous studies suggest that seasonal water stress is one main driver of phenology and related vegetation dynamics in seasonally dry tropical forests. Species that coexist in seasonally dry tropical forests have different plant traits, experience different degrees of plant water stress and show distinctive phenological patterns. However, the observed diversity in plant phenology and related vegetation dynamics is poorly represented in current dynamic vegetation models. In this study, we employ a new modeling approach to enhance our model skills in seasonally dry tropical forests. First, we implement a new plant hydraulic module under the framework of a state-of-the-art dynamic vegetation model, Ecosystem Demography 2 (ED2). Second, we link plant water stress with several key coordinated plant traits. Unlike previous models, the updated ED2 does not prescribe leaf phenology (deciduous or evergreen) and plant water stress is not determined by empirical water stress factors or by soil moisture alone. Instead, the model tracks more mechanistic indicators of plant water stress like leaf water potential, accounts for different abilities to tolerate water stress among plant functional types and predicts dry season leaf deciduousness and related vegetation dynamics. The updated model is then tested with in-situ meteorological data and long-term ecological observations. We also perform numerical experiments to explore the possible biases of ignoring the observed diversity in seasonally dry tropical forests. We find that (i) variations of several key plant traits (specific leaf area, wood density, turgor loss point and rooting depth) can account for the observed distinctive phenological patterns as well as inter-annual variations in vegetation growth among species. (ii) Ignoring the trait-driven trade-offs and diversity in seasonality would introduce significant amount of biases in model predictions of ecosystem energy and water fluxes.

  17. Climate and ET: Does Plant Water Requirements Increase during Droughts?

    NASA Astrophysics Data System (ADS)

    Fipps, G.; Bonaiti, G.; Swanson, C.

    2012-04-01

    With the expected rise in global warming and increased frequency of extreme climate variability in the coming decades, conservation and efficient use of water resources is essential and must make use of the most accurate and representative data available. Historically, governmental and private organizations have used estimates of plant water use estimated from a variety of methods for long-term water planning, for designing hydraulic structures, and for establishing regulatory guidance and conservation programs intended to reduce water waste. In recent years, there has been an expansion of agricultural weather station networks which report daily ETo (potential evapotranspiration) and commercial irrigation controllers with instrumentation which calculate real-time ETo from weather parameters. Efforts are underway to use this more precise information for regional water planning and ETo is routinely used for designing and implementing drought response programs. The year 2011 marked the driest year on record in the State of Texas. Compounding the lack of rainfall was record heat during the summer of 2011. In 2011, real-time ETo (reference evapotranspiration) data in Texas was 30 to 50% higher than historic averages. The implications are quite serious, as most current water planning and drought contingency plans do not take into consideration increases in ET during such periods, and irrigation planning and capacity sizing are based on historic averages of consumptive use. This paper examines the relationship between ET and climate during this extreme climatic event. While the solar radiation was near normal levels, temperature and wind was much higher and dew points much lower than norms. The variability and statistical difference between long term average ETo and ETo measurements (from 2006 to 2011) for selected weather stations of the Texas ET Network.

  18. Water and Plant Cells: Notes on a Teaching Scheme for O-Level.

    ERIC Educational Resources Information Center

    Grenville, H. W.

    1983-01-01

    Offers suggestions for teaching some aspects of water economy in plants. These include diffusion/osmosis, water transport, the part played by turgor in structural support, and its implications for plant organs or whole plants. Several practical demonstrations/experiments are also described. (JN)

  19. Woodland Decomposition.

    ERIC Educational Resources Information Center

    Napier, J.

    1988-01-01

    Outlines the role of the main organisms involved in woodland decomposition and discusses some of the variables affecting the rate of nutrient cycling. Suggests practical work that may be of value to high school students either as standard practice or long-term projects. (CW)

  20. Sector Decomposition

    E-print Network

    Gudrun Heinrich

    2008-05-16

    Sector decomposition is a constructive method to isolate divergences from parameter integrals occurring in perturbative quantum field theory. We explain the general algorithm in detail and review its application to multi-loop Feynman parameter integrals as well as infrared divergent phase-space integrals over real radiation matrix elements.

  1. Phase I: the pipeline-gas demonstration plant. Demonstration plant engineering and design. Volume 18. Plant Section 2700 - Waste Water Treatment

    SciTech Connect

    1981-05-01

    Contract No. EF-77-C-01-2542 between Conoco Inc. and the US Department of Energy provides for the design, construction, and operation of a demonstration plant capable of processing bituminous caking coals into clean pipeline quality gas. The project is currently in the design phase (Phase I). This phase is scheduled to be completed in June 1981. One of the major efforts of Phase I is the process and project engineering design of the Demonstration Plant. The design has been completed and is being reported in 24 volumes. This is Volume 18 which reports the design of Plant Section 2700 - Waste Water Treatment. The objective of the Waste Water Treatment system is to collect and treat all plant liquid effluent streams. The system is designed to permit recycle and reuse of the treated waste water. Plant Section 2700 is composed of primary, secondary, and tertiary waste water treatment methods plus an evaporation system which eliminates liquid discharge from the plant. The Waste Water Treatment Section is designed to produce 130 pounds per hour of sludge that is buried in a landfill on the plant site. The evaporated water is condensed and provides a portion of the make-up water to Plant Section 2400 - Cooling Water.

  2. Litter quality, stream characteristics and litter diversity influence decomposition rates and macroinvertebrates

    E-print Network

    Marks, Jane

    Litter quality, stream characteristics and litter diversity influence decomposition rates importance of litter quality and stream characteristics in determining decomposition rate whether plant species diversity affects rate. 3. Decomposition rate was affected by both litter quality

  3. Trade-Offs in Resource Allocation Among Moss Species Control Decomposition in Boreal Peatlands

    SciTech Connect

    Turetsky, M. R.; Crow, S. E.; Evans, R. J.; Vitt, D. H.; Wieder, R. K.

    2008-01-01

    We separated the effects of plant species controls on decomposition rates from environmental controls in northern peatlands using a full factorial, reciprocal transplant experiment of eight dominant bryophytes in four distinct peatland types in boreal Alberta, Canada. Standard fractionation techniques as well as compound-specific pyrolysis molecular beam mass spectrometry were used to identify a biochemical mechanism underlying any interspecific differences in decomposition rates. We found that over a 3-year field incubation, individual moss species and not micro-environmental conditions controlled early stages of decomposition. Across species, Sphagnum mosses exhibited a trade-off in resource partitioning into metabolic and structural carbohydrates, a pattern that served as a strong predictor of litter decomposition. Decomposition rates showed a negative co-variation between species and their microtopographic position, as species that live in hummocks decomposed slowly but hummock microhabitats themselves corresponded to rapid decomposition rates. By forming litter that degrades slowly, hummock mosses appear to promote the maintenance of macropore structure in surface peat hummocks that aid in water retention. Many northern regions are experiencing rapid climate warming that is expected to accelerate the decomposition of large soil carbon pools stored within peatlands. However, our results suggest that some common peatland moss species form tissue that resists decomposition across a range of peatland environments, suggesting that moss resource allocation could stabilize peatland carbon losses under a changing climate.

  4. Engineering Salinity and Water-Stress Tolerance in Crop Plants: Getting Closer to the Field

    E-print Network

    Blumwald, Eduardo

    Engineering Salinity and Water-Stress Tolerance in Crop Plants: Getting Closer to the Field ZVI PELEG,* MARIS P. APSE{ AND EDUARDO BLUMWALD*,1 *Department of Plant Sciences, University of California ................................................................. 407 II. Plant Responses to Drought and Salinity Stress............................ 408 A. Plants

  5. Impact of drought on U.S. steam electric power plant cooling water intakes and related water resource management issues.

    SciTech Connect

    Kimmell, T. A.; Veil, J. A.; Environmental Science Division

    2009-04-03

    This report was funded by the U.S. Department of Energy's (DOE's) National Energy Technology Laboratory (NETL) Existing Plants Research Program, which has an energy-water research effort that focuses on water use at power plants. This study complements their overall research effort by evaluating water availability at power plants under drought conditions. While there are a number of competing demands on water uses, particularly during drought conditions, this report focuses solely on impacts to the U.S. steam electric power plant fleet. Included are both fossil-fuel and nuclear power plants. One plant examined also uses biomass as a fuel. The purpose of this project is to estimate the impact on generation capacity of a drop in water level at U.S. steam electric power plants due to climatic or other conditions. While, as indicated above, the temperature of the water can impact decisions to halt or curtail power plant operations, this report specifically examines impacts as a result of a drop in water levels below power plant submerged cooling water intakes. Impacts due to the combined effects of excessive temperatures of the returned cooling water and elevated temperatures of receiving waters (due to high ambient temperatures associated with drought) may be examined in a subsequent study. For this study, the sources of cooling water used by the U.S. steam electric power plant fleet were examined. This effort entailed development of a database of power plants and cooling water intake locations and depths for those plants that use surface water as a source of cooling water. Development of the database and its general characteristics are described in Chapter 2 of this report. Examination of the database gives an indication of how low water levels can drop before cooling water intakes cease to function. Water level drops are evaluated against a number of different power plant characteristics, such as the nature of the water source (river vs. lake or reservoir) and type of plant (nuclear vs. fossil fuel). This is accomplished in Chapter 3. In Chapter 4, the nature of any compacts or agreements that give priority to users (i.e., which users must stop withdrawing water first) is examined. This is examined on a regional or watershed basis, specifically for western water rights, and also as a function of federal and state water management programs. Chapter 5 presents the findings and conclusions of this study. In addition to the above, a related intent of this study is to conduct preliminary modeling of how lowered surface water levels could affect generating capacity and other factors at different regional power plants. If utility managers are forced to take some units out of service or reduce plant outputs, the fuel mix at the remaining plants and the resulting carbon dioxide emissions may change. Electricity costs and other factors may also be impacted. Argonne has conducted some modeling based on the information presented in the database described in Chapter 2 of this report. A separate report of the modeling effort has been prepared (Poch et al. 2009). In addition to the U.S. steam electric power plant fleet, this modeling also includes an evaluation of power production of hydroelectric facilities. The focus of this modeling is on those power plants located in the western United States.

  6. Simulated acid rain alters litter decomposition and enhances the allelopathic potential of the invasive plant Wedelia trilobata (Creeping Daisy)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Invasive species and acid rain cause global environmental problems. Limited information exists, however, concerning the effects of acid rain on the invasiveness of these plants. For example, creeping daisy, an invasive exotic allelopathic weed, has caused great damage in southern China where acid ra...

  7. A Cold Water Pipe for an OTEC Pilot Plant: Design Considerations

    E-print Network

    A Cold Water Pipe for an OTEC Pilot Plant: Design Considerations Kara Silver Abstract Ocean Thermal Energy Conversion (OTEC) is a baseload renewable technology for tropical countries and islands. In order (HDPE) Cold Water Pipe (CWP) for a floating OTEC pilot plant, presumably in Hawaiian waters

  8. Small-scale Geothermal Power Plants Using Hot Spring Water

    NASA Astrophysics Data System (ADS)

    Tosha, T.; Osato, K.; Kiuchi, T.; Miida, H.; Okumura, T.; Nakashima, H.

    2013-12-01

    The installed capacity of the geothermal power plants has been summed up to be about 515MW in Japan. However, the electricity generated by the geothermal resources only contributes to 0.2% of the whole electricity supply. After the catastrophic earthquake and tsunami devastated the Pacific coast of north-eastern Japan on Friday, March 11, 2011, the Japanese government is encouraging the increase of the renewable energy supply including the geothermal. It needs, however, more than 10 years to construct the geothermal power plant with more than 10MW capacity since the commencement of the development. Adding the problem of the long lead time, high temperature fluid is mainly observed in the national parks and the high quality of the geothermal resources is limited. On the other hand hot springs are often found. The utilisation of the low temperature hot water becomes worthy of notice. The low temperature hot water is traditionally used for bathing and there are many hot springs in Japan. Some of the springs have enough temperature and enthalpy to turn the geothermal turbine but a new technology of the binary power generation makes the lower temp fluid to generate electricity. Large power generators with the binary technology are already installed in many geothermal fields in the world. In the recent days small-scale geothermal binary generators with several tens to hundreds kW capacity are developed, which are originally used by the waste heat energy in an iron factory and so on. The newly developed binary unit is compact suitable for the installation in a Japanese inn but there are the restrictions for the temperature of the hot water and the working fluid. The binary power unit using alternatives for chlorofluorocarbon as the working fluid is relatively free from the restriction. KOBELCO, a company of the Kobe Steel Group, designed and developed the binary power unit with an alternative for chlorofluorocarbon. The unit has a 70 MW class electric generator. Three units have been installed in Obama Hot Spring area, Nagasaki Prefecture, where about 15,000 tonnes of hot water are produced in a day and more than 35% of the hot water flow directly to the sea. Another demonstration experiments are also conducted in several hot spring areas. In this study we will review several examples to utilise low temperature hot springs in Japan. Binary Power Unit at Obama (Fujino, 2013)

  9. Solar geoengineering, atmospheric water vapor transport, and land plants

    NASA Astrophysics Data System (ADS)

    Caldeira, Ken; Cao, Long

    2015-04-01

    This work, using the GeoMIP database supplemented by additional simulations, discusses how solar geoengineering, as projected by the climate models, affects temperature and the hydrological cycle, and how this in turn is related to projected changes in net primary productivity (NPP). Solar geoengineering simulations typically exhibit reduced precipitation. Solar geoengineering reduces precipitation because solar geoengineering reduces evaporation. Evaporation precedes precipitation, and, globally, evaporation equals precipitation. CO2 tends to reduce evaporation through two main mechanisms: (1) CO2 tends to stabilize the atmosphere especially over the ocean, leading to a moister atmospheric boundary layer over the ocean. This moistening of the boundary layer suppresses evaporation. (2) CO2 tends to diminish evapotranspiration, at least in most land-surface models, because higher atmospheric CO2 concentrations allow leaves to close their stomata and avoid water loss. In most high-CO2 simulations, these effects of CO2 which tend to suppress evaporation are masked by the tendency of CO2-warming effect to increase evaporation. In a geoengineering simulation, with the warming effect of CO2 largely offset by the solar geoengineering, the evaporation suppressing characteristics of CO2 are no longer masked and are clearly exhibited. Decreased precipitation in solar geoengineering simulations is a bit like ocean acidification - an effect of high CO2 concentrations that is not offset by solar geoengineering. Locally, precipitation ultimately either evaporates (much of that through the leaves of plants) or runs off through groundwater to streams and rivers. On long time scales, runoff equals precipitation minus evaporation, and thus, water runoff generated at a location is equal to the net atmospheric transport of water to that location. Runoff typically occurs where there is substantial soil moisture, at least seasonally. Locations where there is enough water to maintain runoff are typically locations where there is sufficient water to maintain plant growth. This work aims at: (i) Identifying the geographical distribution of sensitivity of modeled-NPP to changes in CO2, temperature, and various parameters related to the hydrological cycle; (ii) Geographically partitioning changes in modeled-NPP to changes in CO2, temperature, and hydrological variables (and a non-linear interaction term).

  10. TOXICITY TESTS OF EFFLUENTS WITH MARSH PLANTS IN WATER AND SEDIMENT

    EPA Science Inventory

    Methods are described for toxicity testing of water and sediment with the rooted marsh plants, Echinochloa crusgalli var. crusgalli and var. zelavensis (freshwater) and Spartina alterniflora (estuarine). ive industrial effluents, a sewage treatment plant effluent and a herbicide ...

  11. Water Use Efficiency in Plant Growth and Ambient Carbon Dioxide Level 

    E-print Network

    van Bavel, C. H. M.

    1972-01-01

    This report examines the validity and explores the practical implications of the proposition that CO2 enrichment of the leaf environment enhances plant growth and, simultaneously decreases plant water use. A theoretical ...

  12. Rangeland - plant responses to elevated CO{sub 2}. Final report, October 1988--October 1993

    SciTech Connect

    1997-05-01

    Research is described on plant (tallgrass) response to elevated carbon dioxide. Variables addressed include biomass production, as well as water use efficiency, photosynthetic capacity, decomposition, nutrient cycling, and forage quality.

  13. Water relations, nutrient content and developmental responses of Euonymus plants irrigated with water of different degrees of salinity and quality.

    PubMed

    Gómez-Bellot, María José; Alvarez, Sara; Castillo, Marco; Bañón, Sebastián; Ortuño, María Fernanda; Sánchez-Blanco, María Jesús

    2013-07-01

    For 20 weeks, the physiological responses of Euonymus japonica plants to different irrigation sources were studied. Four irrigation treatments were applied at 100 % water holding capacity: control (electrical conductivity (EC) <0.9 dS m(-1)); irrigation water normally used in the area (irrigator's water) IW (EC: 1.7 dS m(-1)); NaCl solution, NaCl (EC: 4 dS m(-1)); and wastewater, WW (EC: 4 dS m(-1)). This was followed by a recovery period of 13 weeks, when all the plants were rewatered with the same amount and quality of irrigation water as the control plants. Despite the differences in the chemical properties of the water used, the plants irrigated with NaCl and WW showed similar alterations in growth and size compared with the control even at the end of the recovery period. Leaf number was affected even when the EC of the irrigation water was of 1.7 dS m(-1) (IW), indicating the salt sensitivity of this parameter. Stomatal conductance (gs) and photosynthesis (Pn), as well as stem water potential (?stem), were most affected in plants irrigated with the most saline waters (NaCl and WW). At the end of the experiment the above parameters recovered, while IW plants showed similar values to the control. The higher Na(+) and Cl(+) uptake by NaCl and WW plants led them to show osmotic adjustment throughout the experiment. The highest amount of boron found in WW plants did not affect root growth. Wastewater can be used as a water management strategy for ornamental plant production, as long as the water quality is not too saline, since the negative effect of salt on the aesthetic value of plants need to be taken into consideration. PMID:23306649

  14. Dynamic aspects of soil water availability for isohydric plants: Focus on root hydraulic resistances

    NASA Astrophysics Data System (ADS)

    Couvreur, V.; Vanderborght, J.; Draye, X.; Javaux, M.

    2014-11-01

    Soil water availability for plant transpiration is a key concept in agronomy. The objective of this study is to revisit this concept and discuss how it may be affected by processes locally influencing root hydraulic properties. A physical limitation to soil water availability in terms of maximal flow rate available to plant leaves (Qavail) is defined. It is expressed for isohydric plants, in terms of plant-centered variables and properties (the equivalent soil water potential sensed by the plant, ?s eq; the root system equivalent conductance, Krs; and a threshold leaf water potential, ?leaf lim). The resulting limitation to plant transpiration is compared to commonly used empirical stress functions. Similarities suggest that the slope of empirical functions might correspond to the ratio of Krs to the plant potential transpiration rate. The sensitivity of Qavail to local changes of root hydraulic conductances in response to soil matric potential is investigated using model simulations. A decrease of radial conductances when the soil dries induces earlier water stress, but allows maintaining higher night plant water potentials and higher Qavail during the last week of a simulated 1 month drought. In opposition, an increase of radial conductances during soil drying provokes an increase of hydraulic redistribution and Qavail at short term. This study offers a first insight on the effect of dynamic local root hydraulic properties on soil water availability. By better understanding complex interactions between hydraulic processes involved in soil-plant hydrodynamics, better prospects on how root hydraulic traits mitigate plant water stress might be achieved.

  15. The functional role of carbonate-cemented soil horizons in desert ecosystems: Spatial and temporal dynamics of plant water availability

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In water limited ecosystems, soil profile characteristics can control plant community composition and production through their effects on spatial and temporal patterns of plant available water. Little is known, however, about water availability in soil horizons cemented with carbonates (petrocalcic ...

  16. Engineering the use of green plants to reduce produced water disposal volume.

    SciTech Connect

    Hinchman, R.; Mollock, G. N.; Negri, M. C.; Settle, T.

    1998-01-29

    In 1990, the Laboratory began an investigation into biological approaches for the reduction of water produced from oil and gas wells. In the spring of 1995, the Company began an on-site experiment at an oil/gas lease in Oklahoma using one of these approaches. The process, known as phytoremediation, utilizes the ability of certain salt tolerant plants to draw the produced water through their roots, transpire the water from their leaves, and thereby reduce overall water disposal volumes and costs. At the Company experimental site, produced water flows through a trough where green plants (primarily cordgrass) have been planted in pea gravel. The produced water is drawn into the plant through its roots, evapotranspirates and deposits a salt residue on the plant leaves. The plant leaves are then harvested and used by a local rancher as cattle feed. The produced water is tested to assure it contains nothing harmful to cattle. In 1996, the Company set up another trough to compare evaporation rates using plants versus using an open container without plants. Data taken during all four seasons (water flow rate, temperature, pH, and conductivity) have shown that using plants to evapotranspirate produced water is safe, more cost effective than traditional methods and is environmentally sound.

  17. Optimization of conventional water treatment plant using dynamic programming.

    PubMed

    Mostafa, Khezri Seyed; Bahareh, Ghafari; Elahe, Dadvar; Pegah, Dadras

    2015-12-01

    In this research, the mathematical models, indicating the capability of various units, such as rapid mixing, coagulation and flocculation, sedimentation, and the rapid sand filtration are used. Moreover, cost functions were used for the formulation of conventional water and wastewater treatment plant by applying Clark's formula (Clark, 1982). Also, by applying dynamic programming algorithm, it is easy to design a conventional treatment system with minimal cost. The application of the model for a case reduced the annual cost. This reduction was approximately in the range of 4.5-9.5% considering variable limitations. Sensitivity analysis and prediction of system's feedbacks were performed for different alterations in proportion from parameters optimized amounts. The results indicated (1) that the objective function is more sensitive to design flow rate (Q), (2) the variations in the alum dosage (A), and (3) the sand filter head loss (H). Increasing the inflow by 20%, the total annual cost would increase to about 12.6%, while 20% reduction in inflow leads to 15.2% decrease in the total annual cost. Similarly, 20% increase in alum dosage causes 7.1% increase in the total annual cost, while 20% decrease results in 7.9% decrease in the total annual cost. Furthermore, the pressure decrease causes 2.95 and 3.39% increase and decrease in total annual cost of treatment plants. PMID:23625909

  18. Water quality investigation of Kingston Fossil Plant dry ash stacking

    SciTech Connect

    Bohac, C.E.

    1990-04-01

    Changing to a dry ash disposal systems at Kingston Fossil Plant (KFP) raises several water quality issues. The first is that removing the fly ash from the ash pond could alter the characteristics of the ash pond discharge to the river. The second concerns proper disposal of the runoff and possibly leachate from the dry ash stack. The third is that dry ash stacking might change the potential for groundwater contamination at the KFP. This report addresses each of these issues. The effects on the ash pond and its discharge are described first. The report is intended to provide reference material to TVA staff in preparation of environmental review documents for new ash disposal areas at Kingston. Although the investigation was directed toward analysis of dry stacking, considerations for other disposal options are also discussed. This report was reviewed in draft form under the title Assessment of Kingston Fossil Plant Dry Ash Stacking on the Ash Pond and Groundwater Quality.'' 11 refs., 3 figs., 18 tabs.

  19. Computing Cylindrical Algebraic Decomposition via Triangular Decomposition

    E-print Network

    Moreno Maza, Marc

    Computing Cylindrical Algebraic Decomposition via Triangular Decomposition Changbo Chen ORCCA of Trustworthy Computing East China Normal University, Shanghai, China lyang@sei.ecnu.edu.cn ABSTRACT Cylindrical decomposition in order to obtain an F-invariant cylindrical decomposition of the n-dimensional complex space

  20. Unifying two Graph Decompositions with Modular Decomposition

    E-print Network

    Fondements et Applications, Université Paris 7

    Unifying two Graph Decompositions with Modular Decomposition Binh-Minh Bui-Xuan1 , Michel Habib2, tournaments, digraphs, and 2-structures. We show that, under some axioms, a unique decomposition tree exists computation, and decomposition tree computation when the tree exists. Our results unify many known

  1. Georgia-Pacific Palatka Plant Uses Thermal Pinch Analysis and Evaluates Water Reduction in Plant-Wide Energy Assessment

    SciTech Connect

    2002-12-01

    This OIT BestPractices Case Study describes the methods and results used in a plant-wide assessment at a Georgia-Pacific paper mill in Palatka, FL. Assessment personnel recommended several projects, which, if implemented, have the potential to save the plant more than 729,000 MMBtu per year and $2.9 million per year. In addition, the plant could reduce water use by 2,100 gallons per minute.

  2. Efficacy of aqueous plant extract in disinfecting water of different physicochemical properties.

    PubMed

    Kirui, J K; Kotut, K; Okemo, P O

    2015-09-01

    This study explored the possibility of disinfecting water using aqueous extracts of medicinal plants. Seven medicinal plants used by Samburu herbalists for the treatment of stomach illnesses were investigated for water disinfection. Aqueous extracts of the dried powdered plant material were directly used to treat the water samples collected. Efficacy of water treatment with medicinal plants expressed as percentage reduction in bacterial colonies revealed that Acacia nilotica extract with a mean percentage reduction of 99.86% was the most effective at reducing the number of bacterial colonies. Albizia anthelmintica extract with a mean of 9.47% was the least effective at reducing the number of bacterial colonies. The study also revealed a possible interaction between plant extracts and water source (P<0.05, df=54). The results obtained in this study point out a possibility of using aqueous extracts from A. nilotica in disinfecting water of different physicochemical properties. PMID:26322770

  3. 18 CFR 420.51 - Hydroelectric power plant water use charges.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 18 Conservation of Power and Water Resources 2 2010-04-01 2010-04-01 false Hydroelectric power plant water use charges. 420.51 Section 420.51 Conservation of Power and Water Resources DELAWARE RIVER BASIN COMMISSION ADMINISTRATIVE MANUAL BASIN REGULATIONS-WATER SUPPLY CHARGES Hydroelectric Power...

  4. Decomposition in northern Minnesota peatlands

    SciTech Connect

    Farrish, K.W.

    1985-01-01

    Decomposition in peatlands was investigated in northern Minnesota. Four sites, an ombrotrophic raised bog, an ombrotrophic perched bog and two groundwater minerotrophic fens, were studied. Decomposition rates of peat and paper were estimated using mass-loss techniques. Environmental and substrate factors that were most likely to be responsible for limiting decomposition were monitored. Laboratory incubation experiments complemented the field work. Mass-loss over one year in one of the bogs, ranged from 11 percent in the upper 10 cm of hummocks to 1 percent at 60 to 100 cm depth in hollows. Regression analysis of the data for that bog predicted no mass-loss below 87 cm. Decomposition estimates on an area basis were 2720 and 6460 km/ha yr for the two bogs; 17,000 and 5900 kg/ha yr for the two fens. Environmental factors found to limit decomposition in these peatlands were reducing/anaerobic conditions below the water table and cool peat temperatures. Substrate factors found to limit decomposition were low pH, high content of resistant organics such as lignin, and shortages of available N and K. Greater groundwater influence was found to favor decomposition through raising the pH and perhaps by introducing limited amounts of dissolved oxygen.

  5. Geographic, technologic, and economic analysis of using reclaimed water for thermoelectric power plant cooling.

    PubMed

    Stillwell, Ashlynn S; Webber, Michael E

    2014-04-15

    Use of reclaimed water-municipal wastewater treatment plant effluent-in nonpotable applications can be a sustainable and efficient water management strategy. One such nonpotable application is at thermoelectric power plants since these facilities require cooling, often using large volumes of freshwater. To evaluate the geographic, technologic, and economic feasibility of using reclaimed water to cool thermoelectric power plants, we developed a spatially resolved model of existing power plants. Our model integrates data on power plant and municipal wastewater treatment plant operations into a combined geographic information systems and optimization approach to evaluate the feasibility of cooling system retrofits. We applied this broadly applicable methodology to 125 power plants in Texas as a test case. Results show that sufficient reclaimed water resources exist within 25 miles of 92 power plants (representing 61% of capacity and 50% of generation in our sample), with most of these facilities meeting both short-term and long-term water conservation cost goals. This retrofit analysis indicates that reclaimed water could be a suitable cooling water source for thermoelectric power plants, thereby mitigating some of the freshwater impacts of electricity generation. PMID:24625241

  6. A Series RCL Circuit Theory for Analyzing Non-Steady-State Water Uptake of Maize Plants

    NASA Astrophysics Data System (ADS)

    Zhuang, Jie; Yu, Gui-Rui; Nakayama, Keiichi

    2014-10-01

    Understanding water uptake and transport through the soil-plant continuum is vital for ecosystem management and agricultural water use. Plant water uptake under natural conditions is a non-steady transient flow controlled by root distribution, plant configuration, soil hydraulics, and climatic conditions. Despite significant progress in model development, a mechanistic description of transient water uptake has not been developed or remains incomplete. Here, based on advanced electrical network theory (RLC circuit theory), we developed a non-steady state biophysical model to mechanistically analyze the fluctuations of uptake rates in response to water stress. We found that the non-steady-state model captures the nature of instantaneity and hysteresis of plant water uptake due to the considerations of water storage in plant xylem and coarse roots (capacitance effect), hydraulic architecture of leaf system (inductance effect), and soil-root contact (fuse effect). The model provides insights into the important role of plant configuration and hydraulic heterogeneity in helping plants survive an adverse environment. Our tests against field data suggest that the non-steady-state model has great potential for being used to interpret the smart water strategy of plants, which is intrinsically determined by stem size, leaf size/thickness and distribution, root system architecture, and the ratio of fine-to-coarse root lengths.

  7. Improvement of growth rate of plants by bubble discharge in water

    NASA Astrophysics Data System (ADS)

    Takahata, Junichiro; Takaki, Koichi; Satta, Naoya; Takahashi, Katsuyuki; Fujio, Takuya; Sasaki, Yuji

    2015-01-01

    The effect of bubble discharge in water on the growth rate of plants was investigated experimentally for application to plant cultivation systems. Spinach (Spinacia oleracea), radish (Raphanus sativus var. sativus), and strawberry (Fragaria × ananassa) were used as specimens to clarify the effect of the discharge treatment on edible parts of the plants. The specimens were cultivated in pots filled with artificial soil, which included chicken manure charcoal. Distilled water was sprayed on the artificial soil and drained through a hole in the pots to a water storage tank. The water was circulated from the water storage tank to the cultivation pots after 15 or 30 min discharge treatment on alternate days. A magnetic compression-type pulsed power generator was used to produce the bubble discharge with a repetition rate of 250 pps. The plant height in the growth phase and the dry weight of the harvested plants were improved markedly by the discharge treatment in water. The soil and plant analyzer development (SPAD) value of the plants also improved in the growth phase of the plants. The concentration of nitrate nitrogen, which mainly contributed to the improvement of the growth rate, in the water increased with the discharge treatment. The Brix value of edible parts of Fragaria × ananassa increased with the discharge treatment. The inactivation of bacteria in the water was also confirmed with the discharge treatment.

  8. ONE MGD ION EXCHANGE PLANT FOR REMOVAL OF NITRATE FROM WELL WATER

    EPA Science Inventory

    A full scale 1 mgd demonstration plant, using ion exchange, for removal of nitrate from well water was built at McFarland, California. The plant has been performing satisfactorily in the semi-automatic mode since October 1983. Full automation of the plant was completed in June 19...

  9. Plant nitrogen uptake drives responses of productivity to nitrogen and water addition in a grassland

    PubMed Central

    Lü, Xiao-Tao; Dijkstra, Feike A.; Kong, De-Liang; Wang, Zheng-Wen; Han, Xing-Guo

    2014-01-01

    Increased atmospheric nitrogen (N) deposition and altered precipitation regimes have profound impacts on ecosystem functioning in semiarid grasslands. The interactions between those two factors remain largely unknown. A field experiment with N and water additions was conducted in a semiarid grassland in northern China. We examined the responses of aboveground net primary production (ANPP) and plant N use during two contrasting hydrological growing seasons. Nitrogen addition had no impact on ANPP, which may be accounted for by the offset between enhanced plant N uptake and decreased plant nitrogen use efficiency (NUE). Water addition significantly enhanced ANPP, which was largely due to enhanced plant aboveground N uptake. Nitrogen and water additions significantly interacted to affect ANPP, plant N uptake and N concentrations at the community level. Our observations highlight the important role of plant N uptake and use in mediating the effects of N and water addition on ANPP. PMID:24769508

  10. Plant nitrogen uptake drives responses of productivity to nitrogen and water addition in a grassland.

    PubMed

    Lü, Xiao-Tao; Dijkstra, Feike A; Kong, De-Liang; Wang, Zheng-Wen; Han, Xing-Guo

    2014-01-01

    Increased atmospheric nitrogen (N) deposition and altered precipitation regimes have profound impacts on ecosystem functioning in semiarid grasslands. The interactions between those two factors remain largely unknown. A field experiment with N and water additions was conducted in a semiarid grassland in northern China. We examined the responses of aboveground net primary production (ANPP) and plant N use during two contrasting hydrological growing seasons. Nitrogen addition had no impact on ANPP, which may be accounted for by the offset between enhanced plant N uptake and decreased plant nitrogen use efficiency (NUE). Water addition significantly enhanced ANPP, which was largely due to enhanced plant aboveground N uptake. Nitrogen and water additions significantly interacted to affect ANPP, plant N uptake and N concentrations at the community level. Our observations highlight the important role of plant N uptake and use in mediating the effects of N and water addition on ANPP. PMID:24769508

  11. Evaluation of Effectiveness Technological Process of Water Purification Exemplified on Modernized Water Treatment Plant at Otoczna

    NASA Astrophysics Data System (ADS)

    Jordanowska, Joanna; Jakubus, Monika

    2014-12-01

    The article presents the work of the Water Treatment Plant in the town of Otoczna, located in the Wielkopolska province, before and after the modernization of the technological line. It includes the quality characteristics of the raw water and treated water with particular emphasis on changes in the quality indicators in the period 2002 -2012 in relation to the physicochemical parameters: the content of total iron and total manganese, the ammonium ion as well as organoleptic parameters(colour and turbidity). The efficiency of technological processes was analysed, including the processes of bed start up with chalcedonic sand to remove total iron and manganese and ammonium ion. Based on the survey, it was found that the applied modernization helped solve the problem of water quality, especially the removal of excessive concentrations of iron, manganese and ammonium nitrogen from groundwater. It has been shown that one year after modernization of the technological line there was a high reduction degree of most parameters, respectively for the general iron content -99%, general manganese - 93% ammonia - 93%, turbidity - 94%. It has been proved, that chalcedonic turned out to be better filter material than quartz sand previously used till 2008. The studies have confirmed that the stage of modernization was soon followed by bed start-up for removing general iron from the groundwater. The stage of manganese removal required more time, about eight months for bed start-up. Furthermore, the technological modernization contributed to the improvement of the efficiency of the nitrification process.

  12. Is the U.S. experience replicable? A decomposition of U.S. water use since 1950

    NASA Astrophysics Data System (ADS)

    Debaere, P.

    2014-12-01

    Blue water withdrawals in the United States since 1950 show a remarkable pattern. After doubling between 1950 and 1980, water use slightly declined in spite of a doubling in GDP, 30 percent population growth and a 70 percent increase in per capita GDP since 1980. We relate this remarkable pattern to the changing long-term structural changes of the U.S. economy as it became a service economy, experiencing a decrease in relative share of manufacturing and a secular decline in agriculture. Drawing on Leontief (1970)'s seminal analysis, we decompose the U.S. water use in terms of scale, composition and technology. We find that about 1/3 of water saving can be attributed to shifting final demand by domestic and foreign buyers for U.S. products; slightly more than a 1/3 relates to the changing input output structure that characterizes U.S. production, and less than 1/3 is to be attributed to water productivity gains related to improvements in technology. In addition, our estimates indicate that the vast majority of the water productivity gains due to technological improvements stem from gains in water/KWh in electricity generation. Finally, while globalization and the growing water content of net imports increased for the U.S. since 1950, they by no means overturn the increased water saving due to changing sectoral composition of the U.S. economy.

  13. Optimization Under Uncertainty for Water Consumption in a Pulverized Coal Power Plant

    SciTech Connect

    Juan M. Salazara; Stephen E. Zitney; Urmila M. Diwekara

    2009-01-01

    Pulverized coal (PC) power plants are widely recognized as major water consumers whose operability has started to be affected by drought conditions across some regions of the country. Water availability will further restrict the retrofitting of existing PC plants with water-expensive carbon capture technologies. Therefore, national efforts to reduce water withdrawal and consumption have been intensified. Water consumption in PC plants is strongly associated to losses from the cooling water cycle, particularly water evaporation from cooling towers. Accurate estimation of these water losses requires realistic cooling tower models, as well as the inclusion of uncertainties arising from atmospheric conditions. In this work, the cooling tower for a supercritical PC power plant was modeled as a humidification operation and used for optimization under uncertainty. Characterization of the uncertainty (air temperature and humidity) was based on available weather data. Process characteristics including boiler conditions, reactant ratios, and pressure ratios in turbines were calculated to obtain the minimum water consumption under the above mentioned uncertainties. In this study, the calculated conditions predicted up to 12% in reduction in the average water consumption for a 548 MW supercritical PC power plant simulated using Aspen Plus. Optimization under uncertainty for these large-scale PC plants cannot be solved with conventional stochastic programming algorithms because of the computational expenses involved. In this work, we discuss the use of a novel better optimization of nonlinear uncertain systems (BONUS) algorithm which dramatically decreases the computational requirements of the stochastic optimization.

  14. Optimization under Uncertainty for Water Consumption in a Pulverized Coal Power Plant

    SciTech Connect

    Juan M. Salazar; Stephen E. Zitney; Urmila Diwekar

    2009-01-01

    Pulverized coal (PC) power plants are widely recognized as major water consumers whose operability has started to be affected by drought conditions across some regions of the country. Water availability will further restrict the retrofitting of existing PC plants with water-expensive carbon capture technologies. Therefore, national efforts to reduce water withdrawal and consumption have been intensified. Water consumption in PC plants is strongly associated to losses from the cooling water cycle, particularly water evaporation from cooling towers. Accurate estimation of these water losses requires realistic cooling tower models, as well as the inclusion of uncertainties arising from atmospheric conditions. In this work, the cooling tower for a supercritical PC power plant was modeled as a humidification operation and used for optimization under uncertainty. Characterization of the uncertainty (air temperature and humidity) was based on available weather data. Process characteristics including boiler conditions, reactant ratios, and pressure ratios in turbines were calculated to obtain the minimum water consumption under the above mentioned uncertainties. In this study, the calculated conditions predicted up to 12% in reduction in the average water consumption for a 548 MW supercritical PC power plant simulated using Aspen Plus. Optimization under uncertainty for these large-scale PC plants cannot be solved with conventional stochastic programming algorithms because of the computational expenses involved. In this work, we discuss the use of a novel better optimization of nonlinear uncertain systems (BONUS) algorithm which dramatically decreases the computational requirements of the stochastic optimization.

  15. Optimal plant water use across temporal scales: bridging eco-hydrological theories and plant eco-physiological responses

    NASA Astrophysics Data System (ADS)

    Manzoni, S.; Vico, G.; Palmroth, S.; Katul, G. G.; Porporato, A. M.

    2013-12-01

    In terrestrial ecosystems, plant photosynthesis occurs at the expense of water losses through stomata, thus creating an inherent hydrologic constrain to carbon (C) gains and productivity. While such a constraint cannot be overcome, evolution has led to a number of adaptations that allow plants to thrive under highly variable and often limiting water availability. It may be hypothesized that these adaptations are optimal and allow maximum C gain for a given water availability. A corollary hypothesis is that these adaptations manifest themselves as coordination between the leaf photosynthetic machinery and the plant hydraulic system. This coordination leads to functional relations between the mean hydrologic state, plant hydraulic traits, and photosynthetic parameters that can be used as bridge across temporal scales. Here, optimality theories describing the behavior of stomata and plant morphological features in a fluctuating soil moisture environment are proposed. The overarching goal is to explain observed global patterns of plant water use and their ecological and biogeochemical consequences. The problem is initially framed as an optimal control problem of stomatal closure during drought of a given duration, where maximizing the total photosynthesis under limited and diminishing water availability is the objective function. Analytical solutions show that commonly used transpiration models (in which stomatal conductance is assumed to depend on soil moisture) are particular solutions emerging from the optimal control problem. Relations between stomatal conductance, vapor pressure deficit, and atmospheric CO2 are also obtained without any a priori assumptions under this framework. Second, the temporal scales of the model are expanded by explicitly considering the stochasticity of rainfall. In this context, the optimal control problem becomes a maximization problem for the mean photosynthetic rate. Results show that to achieve maximum C gains under these unpredictable rainfall conditions, plant hydraulic traits (xylem and stomatal response to water availability) and morphological features (leaf and sapwood areas) must be coordinated - thus providing an ecohydrological interpretation of observed coordination (or homeostasis) among hydraulic traits. Moreover, the combinations of hydraulic traits and responses to drought that are optimal are found to depend on both total rainfall and its distribution during the growing season. Both drier conditions and more intense rainfall events interspaced by longer dry periods favor plants with high resistance to cavitation and delayed stomatal closure as soils dry. In contrast, plants in mesic conditions benefit from cavitation prevention through earlier stomatal closure. The proposed ecohydrological optimality criteria can be used as analytical tools to interpret variability in plant water use and predict trends in plant productivity and species composition under future climates.

  16. Mechanics of water collection in plants via morphology change of conical hairs

    NASA Astrophysics Data System (ADS)

    Ito, Fuyu; Komatsubara, Satoshi; Shigezawa, Naoki; Morikawa, Hideaki; Murakami, Yasushi; Yoshino, Katsumi; Yamanaka, Shigeru

    2015-03-01

    In an arid area like the Namib Desert, plants and animals obtain moisture needed for life from mist in the air. There, some plants have hairs or fibrous structures on their leaf surface that reportedly collect fresh water from the air. We examined the morphology and function of leaf hairs of plants during water collection under different circumstances. We studied the water collecting mechanics of several plants having fibrous hairs on their leaves: tomato, balsam pear, Berkheya purpurea, and Lychnis sieboldii. This plant was selected for detailed investigation as a model because this plant originated from dry grassland near Mount Aso in Kyusyu, Japan. We found a unique feature of water collection and release in this plant. The cone-shaped hairs having inner microfibers were reversibly converted to crushed plates that were twisted perpendicularly in dry conditions. Microfibers found in the hairs seem to be responsible for water storage and release. Their unique reciprocal morphological changes, cone-shaped hairs transformed into perpendicularly twisted shapes, depend on the moisture level in the air, and water stored during wet external conditions was released onto the leaf in drier conditions. These morphological changes were recorded as a movie. Simulations explained the formation of the twisted structure. In theoretical analyses, twisted structures were found to give higher mechanical strength. Similar phenomena were found in the other plants described above. These findings pave the way to new bioinspired technology for alleviating global water shortages.

  17. Fast Approximate Convex Decomposition 

    E-print Network

    Ghosh, Mukulika

    2012-10-19

    Approximate convex decomposition (ACD) is a technique that partitions an input object into "approximately convex" components. Decomposition into approximately convex pieces is both more efficient to compute than exact convex decomposition and can...

  18. Detritus Quality Controls Macrophyte Decomposition under Different Nutrient Concentrations in a Eutrophic Shallow Lake, North China

    PubMed Central

    Li, Xia; Cui, Baoshan; Yang, Qichun; Tian, Hanqin; Lan, Yan; Wang, Tingting; Han, Zhen

    2012-01-01

    Macrophyte decomposition is important for carbon and nutrient cycling in lake ecosystems. Currently, little is known about how this process responds to detritus quality and water nutrient conditions in eutrophic shallow lakes in which incomplete decomposition of detritus accelerates the lake terrestrialization process. In this study, we investigated the effects of detritus quality and water nutrient concentrations on macrophyte decomposition in Lake Baiyangdian, China, by analyzing the decomposition of three major aquatic plants at three sites with different pollution intensities (low, medium, and high pollution sites). Detritus quality refers to detritus nutrient contents as well as C?N, C?P, and N?P mass ratios in this study. Effects of detritus mixtures were tested by combining pairs of representative macrophytes at ratios of 75?25, 50?50 and 25?75 (mass basis). The results indicate that the influence of species types on decomposition was stronger than that of site conditions. Correlation analysis showed that mass losses at the end of the experimental period were significantly controlled by initial detritus chemistry, especially by the initial phosphorus (P) content, carbon to nitrogen (C?N), and carbon to phosphorus (C?P) mass ratios in the detritus. The decomposition processes were also influenced by water chemistry. The NO3-N and NH4-N concentrations in the lake water retarded detritus mass loss at the low and high pollution sites, respectively. Net P mineralization in detritus was observed at all sites and detritus P release at the high pollution site was slower than at the other two sites. Nonadditive effects of mixtures tended to be species specific due to the different nutrient contents in each species. Results suggest that the nonadditive effects varied significantly among different sites, indicating that interactions between the detritus quality in species mixtures and site water chemistry may be another driver controlling decomposition in eutrophic shallow lakes. PMID:22848699

  19. Influence of Solar Radiation and Biotic Interactions on Bacterial and Eukaryotic Communities Associated with Sewage Decomposition in Ambient Water - Poster

    EPA Science Inventory

    Sewage and ambient water both consist of a highly complex array of bacteria and eukaryotic microbes. When these communities are mixed, the persistence of sewage-derived pathogens in environmental waters can represent a significant public health concern. Solar radiation and biotic...

  20. Influence of solar radiation and biotic interactions on bacterial and eukaryotic communities associated with sewage decomposition in ambient water

    EPA Science Inventory

    Sewage and ambient water both consist of a highly complex array of bacteria and eukaryotic microbes. When these communities are mixed, the persistence of sewage-derived pathogens in environmental waters can represent a significant public health concern. Solar radiation and biot...

  1. POWER PLANT COOLING WATER CHLORINATION IN NORTHERN CALIFORNIA

    EPA Science Inventory

    A survey was conducted of chlorination practices at five power plants owned and operated by the Pacific Gas and Electric Company. Frequency and duration of chlorination varied significantly from plant to plant and was controlled analytically by the orthotolidine and/or amperometr...

  2. RESPONSES OF WETLAND PLANTS TO EFFLUENTS IN WATER & SEDIMENT

    EPA Science Inventory

    Responses of two wetland vascular plants, Echinochloa crusgalli and Sesbania macrocarpa, exposed to effluents from a coke plant, a pulp mill, a wastewater treatment plant, and the herbicide, hexazinone, were measured in three types of tests: seed germination and early growth, see...

  3. A biomarker based on gene expression indicates plant water status in controlled and natural environments.

    PubMed

    Marchand, Gwenaëlle; Mayjonade, Baptiste; Varès, Didier; Blanchet, Nicolas; Boniface, Marie-Claude; Maury, Pierre; Nambinina Andrianasolo, Fety; Nambinina, Fety Andrianasolo; Burger, Philippe; Debaeke, Philippe; Casadebaig, Pierre; Vincourt, Patrick; Langlade, Nicolas B

    2013-12-01

    Plant or soil water status is required in many scientific fields to understand plant responses to drought. Because the transcriptomic response to abiotic conditions, such as water deficit, reflects plant water status, genomic tools could be used to develop a new type of molecular biomarker. Using the sunflower (Helianthus annuus L.) as a model species to study the transcriptomic response to water deficit both in greenhouse and field conditions, we specifically identified three genes that showed an expression pattern highly correlated to plant water status as estimated by the pre-dawn leaf water potential, fraction of transpirable soil water, soil water content or fraction of total soil water in controlled conditions. We developed a generalized linear model to estimate these classical water status indicators from the expression levels of the three selected genes under controlled conditions. This estimation was independent of the four tested genotypes and the stage (pre- or post-flowering) of the plant. We further validated this gene expression biomarker under field conditions for four genotypes in three different trials, over a large range of water status, and we were able to correct their expression values for a large diurnal sampling period. PMID:23639099

  4. Thermoeconomic optimizarion of OC-OTEC electricity and water production plants. Final report

    SciTech Connect

    Block, D.L.; Girgis, M.A.; Huggins, J.C.; McCluney, R.; Rotundo, L.; Valenzuela, J.A.; Hutchings, B.J.; Stacy, W.D.; Sam, R.G.; Patel, B.R.

    1984-09-01

    The objectives of this yearlong project were to: (1) assess the economic and technical viability of open-cycle ocean thermal energy conversion of (OC-OTEC) for the production of electricity and/or fresh water based on the current state of the art; (2) develop conceptual designs of optimized OC-OTEC plants that produce electricity and/or fresh water for plant sizes that are economically attractive; and (3) identify the research issues that must be resolved before a commercial plant can be built. Oceanographic data for six potential sites were evaluated and generic site characteristics were developed. The generic site has a 20/sup 0/C temperature differential between the ocean surface and a depth of 1000 m. This temperature differential occurs at a distance of 5 km from shore. Current and projected prices and requirements for electricity and water at potential sites were obtained. The state of the art of components comprising the OC-OTEC plant was reviewed. Design options for each component were identified. The highest performing, least costly, and least technically uncertain design for each component was selected. Component cost and performance models were then developed and integrated into thermoeconomic system models for single- and double-stage OC-OTEC plants that produced electricity and/or fresh water. A computerized optimization procedure was developed to obtain optimal (minimum cost) plant configurations for the production of electricity and/or fresh water. All plant types - floating, moored, shelf-mounted, shallow-water and land-based plants - were evaluated. Based on the state-of-the-art and typical characteristics of potential sites, the primary thrust of the program was directed towards shallow-water and land-based plants. The shallow-water/land-based plant configurations selected had a 5-km long cold-water supply pipe and a 1-km long discharge pipe for the evaporator and condenser.

  5. Decomposition of saltmeadow cordgrass (Spartina patens) in Louisiana coastal marshes

    USGS Publications Warehouse

    Foote, A.L.; Reynolds, K.A.

    1997-01-01

    In Louisiana, plant production rates and associated decomposition rates may be important in offsetting high rates of land loss and subsidence in organic marsh soils. Decomposition of Spartina patens shoot and leaf material was studied by using litter bags in mesohaline marshes in the Barataria and Terrebonne basins of coastal Louisiana. Spartina patens decomposed very slowly with an average decay constant of 0.0007, and approximately 50% of the material remained after 2 years in the field. Material at the Barataria site decomposed faster than did Terrebonne material with trend differences apparent during the first 150 days. This difference might be explained by the higher content of phosphorus in the Barataria material or a flooding period experienced by the Barataria bags during their first 10 days of deployment. Nitrogen and carbon content of the plant material studied did not differ between the two basins. We detected no consistent significant differences in decomposition above, at, or below sediment/water level. Because S. patens is the dominant plant in these marshes, and because it is so slow to decompose, we believe that S. patens shoots are an important addition to vertical accretion and, therefore, marsh elevation.

  6. Withdrawal and consumption of water by thermoelectric power plants in the United States, 2010

    USGS Publications Warehouse

    Diehl, Timothy H.; Harris, Melissa A.

    2014-01-01

    An analysis of 2005 and 2010 EIA-reported water use indicated that withdrawal and consumption declined 18 percent and 34 percent, respectively. Alternative water types (types other than freshwater) accounted for approximately 25 percent of all withdrawals in 2010, most of which occurred at plants with once-through cooling systems using saline and brackish tidal waters. Differences among withdrawal and consumption coefficients based on EIA-reported water use for 2005 and 2010 and heat-budget model results for 2010 reveal opportunities for improving consistency and accuracy of reporting of water-use information at the plant scale.

  7. Prediction of the Maximum Temperature for Life Based on the Stability of Metabolites to Decomposition in Water

    E-print Network

    Bains, William

    The components of life must survive in a cell long enough to perform their function in that cell. Because the rate of attack by water increases with temperature, we can, in principle, predict a maximum temperature above ...

  8. Changes in the resistance to water movement through the soil/plant pathway in salinized sunflower (Helianthus giganteus) 

    E-print Network

    Balint, Donna Elizabeth

    1993-01-01

    The water potential gradient through the plant and the resistance to the viscous flow of water are two properties that may be affected by salinity stress within a plant. In this study, sunflowers (Helianthus giganteus) grown in sand culture were...

  9. Coupled Soil-Plant Water Dynamics During Drought-Rewetting Transitions

    NASA Astrophysics Data System (ADS)

    Volkmann, T. H.; Haberer, K.; Gessler, A.; Weiler, M.

    2013-12-01

    The predicted climate and land-use changes could have dramatic effects on the water balance of the soil-vegetation system, particularly under frequent drought and subsequent rewetting conditions. Yet, estimation of these effects and associated consequences for the structure and functioning of ecosystems, groundwater recharge, drinking water availability, and the water cycle is currently impeded by gaps in our understanding of the spatiotemporal dynamics of soil water in the rooted soil horizons, the dynamics and driving physiological processes of plant water acquisition, and the transpiration from plant leaves under changing environmental conditions. Combining approaches from the disciplines of plant ecophysiology and soil and isotope hydrology, this work aims to fill this gap by quantitatively characterizing the interaction between plant water use - as affected by rooting patterns and ecophysiology of different plant functional groups - and the water balance of variably complex ecosystems with emphasis on drought and rewetting phases. Results from artificial drought and subsequent rewetting in field experiments using isotopically and dye (Brilliant Blue FCF) labeled water conducted on plots of various surface cover (bare soil, grass, beech, oak, vine) established on luvisol on loess in southwestern Germany are presented. Detailed spatiotemporal insights into the coupled short-term (hours to days) dynamics of soil and plant water during the experiments is facilitated by the application of newly developed techniques for high-frequency in-situ monitoring of stable isotope signatures in both pore water and transpired water using commercial laser-based spectrometers in conjunction with plant ecophysiological, soil physical state, and dye staining observations. On the one hand, the spatiotemporal patterns of plant water uptake are assessed and related to morphological and physiological traits driving plant water uptake, functional adaptations of plants to changes of soil water availability, and intra- and interspecies competition for water resources access. On the other hand, the effects of vegetation cover on infiltration, preferential flow paths characteristics, and soil water storage in the rooted soil horizons are investigated. The results of the experiments and the developed methodology will contribute to an improved understanding of ecosystem response and adaptation to drought and short-term changes in environmental conditions.

  10. Plant water relations as affected by heavy metal stress: A review

    SciTech Connect

    Barcelo, J.; Poschenrieder, C. )

    1990-01-01

    Metal toxicity causes multiple direct and indirect effects in plants which concern practically all physiological functions. In this review the effects of excess heavy metals and aluminum on those functions which will alter plant water relations are considered. After a brief comment on the metal effects in cell walls and plasma-lemma, and their consequences for cell expansion growth, the influences of high meal availability on the factors which regulate water entry and water exit in plants are considered. Emphasis is placed on the importance of distinguishing between low water availability in mine and serpentine soils and toxicity effects in plants which may impair the ability of a plant to regulate water uptake. Examples on water relations of both plants grown on metalliferous soil and hydroponics are presented, and the effects of metal toxicity on root growth, water transport and transpiration are considered. It is concluded that future research has to focus on the mechanisms of metal-induced inhibition of both root elongation and morphogenetic processes within roots. In order to understand the relation between metal tolerance and drought resistance better, further studies into metal tolerance mechanisms at the cell wall, membrane and vacuolar level, as well as into the mechanisms of drought resistance of plants adapted to metalliferous soils are required. 135 refs., 7 figs., 6 tabs.

  11. Water deficit stress - host plant nutrient accumulations and associations with phytophagous arthropods

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In addition to making otherwise arable regions less, or nonarable, from lack of life-sustaining water, water deficit also affects the extent to which crops are afflicted by arthropod pests. This chapter focuses on the effects of water deficit stress on physical and nutritional aspects of host plants...

  12. Water Use and Drought Resistance of Turfgrass and Ornamental Landscape Plant Species

    ERIC Educational Resources Information Center

    Domenghini, Jacob Cody

    2012-01-01

    In 2005, turfgrass was estimated to cover approximately 20 million ha of urbanized land. That area is increasing with rapid urbanization, stressing the importance of water conservation in the lawn and landscape industry. Turfgrasses have been identified for replacement by presumably more water-efficient ornamental plant species to conserve water.…

  13. WATER CONSUMPTION AND COSTS FOR VARIOUS STEAM ELECTRIC POWER PLANT COOLING SYSTEMS

    EPA Science Inventory

    The report gives results of a state-of-the-art study, addressing consumptive water use and related costs of various steam electric power plant cooling systems, the availability of water for all uses by area, and the impact of legal constraints on water use in the U.S.

  14. RESIDUE COMPOSITION AND DECOMPOSITION OF SHOOT AND ROOTS AMONG C3 AND C4 SPECIES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Understanding decomposition of plant residue is vital to understanding C and N cycling, both in terms of plant nutrient needs and global C balance. The rate of residue decomposition reflects decomposition of the degrading substrates. Roots typically constitute less than half the total plant biomass,...

  15. Biotic vs. Abiotic Control of Decomposition: A Comparison of the Effects of Simulated Extinctions and

    E-print Network

    Cardinale, Bradley J.

    . It is crucial to understand what factors affect the rate of plant litter decomposition and the relative temperature of 5uC and loss of detritivorous invertebrate and plant litter species affect decomposition rates concurrently to determine their relative impacts on key ecosystem processes such as plant litter decomposition

  16. WATER REUSE IN A WET PROCESS HARDBOARD MANUFACTURING PLANT

    EPA Science Inventory

    Superior Fiber Products, Inc., a manufacturer of smooth on one side wet process hardboard, undertook a project to eliminate any discharge of process water through a program of increasing process water reuse. All but wash up water and some pump seal leak water discharges were elim...

  17. The incidence and implications of clouds for cloud forest plant water relations.

    PubMed

    Goldsmith, Gregory R; Matzke, Nicholas J; Dawson, Todd E

    2013-03-01

    Although clouds are the most recognisable and defining feature of tropical montane cloud forests, little research has focussed on how clouds affect plant functioning. We used satellite and ground-based observations to study cloud and leaf wetting patterns in contrasting tropical montane and pre-montane cloud forests. We then studied the consequences of leaf wetting for the direct uptake of water accumulated on leaf surfaces into the leaves themselves. During the dry season, the montane forest experienced higher precipitation, cloud cover and leaf wetting events of longer duration than the pre-montane forest. Leaf wetting events resulted in foliar water uptake in all species studied. The capacity for foliar water uptake differed significantly between the montane and pre-montane forest plant communities, as well as among species within a forest. Our results indicate that foliar water uptake is common in these forest plants and improves plant water status during the dry season. PMID:23216898

  18. Alternative schemes for production of chilled water and cogeneration of electricity at Ashley Plant

    SciTech Connect

    Not Available

    1989-01-01

    William Tao Associates, Inc. (TAO) evaluated alternative systems for the generation of Chilled Water at Ashley Plant. The generation of chilled water is necessary for several reason; initially as a source of revenue for St. Louis Thermal Energy Corporation (SLTEC), but more importantly as a necessary component of the Trash-to-Energy Plant proposed north of Ashley Plant. The chilled water system provides a base load for steam generated by the Trash-to-Energy Plant. The benefits include reduced tip-fees to the City of St. Louis, lower cost of energy to customers of both the district steam system and the proposed chilled water system, and will result in lower energy and operating costs for the system than if individual services are provided. This symbiotic relationship is main advantage of the Trash-to-Energy system. TAO provided preliminary engineering of the chilled water line route. The basic assumptions of an initial load of 10,000 tons with an ultimate load of 20,000 tons at a temperature difference of 16{degree}F remain. The findings of the pipeline study, although not incorporated into this document, remain valid. Assumptions include the following: An initial design load of 6000 tons which has the capability of growing to 20,000 tons; Incremental costs of steam generated by Ashley Plant and the Trash-to-Energy plant; The turbine room at Ashley Plant is suitable for gut rehab except for turbines No. 7 and No. 9 which should remain operational; and Daily chilled water flow and annual load profile. The paper describes the findings on 8 alternative chiller systems. Additional studies were performed on the following: chilled water storage; low-pressure absorption chiller for balancing plant steam loads; economizer cycle for chiller system; auxiliary equipment energy source; variable flow water pumps; and comparison to satellite chilled water plant study.

  19. The decomposition of the Faroe-Shetland Channel water masses using Parametric Optimum Multi-Parameter analysis

    NASA Astrophysics Data System (ADS)

    McKenna, C.; Berx, B.; Austin, W. E. N.

    2016-01-01

    The Faroe-Shetland Channel (FSC) is an important conduit for the poleward flow of Atlantic water towards the Nordic Seas and, as such, it plays an integral part in the Atlantic's thermohaline circulation. Mixing processes in the FSC are thought to result in an exchange of properties between the channel's inflow and outflow, with wider implications for this circulation; the nature of this mixing in the FSC is, however, uncertain. To constrain this uncertainty, we used a novel empirical method known as Parametric Optimum Multi-Parameter (POMP) analysis to objectively quantify the distribution of water masses in the channel in May 2013. This was achieved by using a combination of temperature and salinity measurements, as well as recently available nutrient and ?18O measurements. The outcomes of POMP analysis are in good agreement with established literature and demonstrate the benefits of representing all five water masses in the FSC. In particular, our results show the recirculation of Modified North Atlantic Water in the surface layers, and the pathways of Norwegian Sea Arctic Intermediate Water and Norwegian Sea Deep Water from north to south for the first time. In a final step, we apply the mixing fractions from POMP analysis to decompose the volume transport through the FSC by water mass. Despite a number of caveats, our study suggests that improved estimates of the volume transport of Atlantic inflow towards the Arctic and, thus, the associated poleward fluxes of salt and heat are possible. A new prospect to more accurately monitor the strength of the FSC branch of the thermohaline circulation emerges from this study.

  20. Study on the TOC concentration in raw water and HAAs in Tehran’s water treatment plant outlet

    PubMed Central

    2013-01-01

    A sampling has been undertaken to investigate the variation of haloacetic acids formation and nature organic matter through 81 samples were collected from three water treatment plant and three major rivers of Tehran Iran. Changes in the total organic matter (TOC), ultraviolet absorbance (UV254), specific ultraviolet absorbance (SUVA) were measured in raw water samples. Haloacetic acids concentrations were monitored using a new static headspace GC-ECD method without a manual pre-concentration in three water treatment plants. The average concentration of TOC and HAAs in three rivers and three water treatment plants in spring, summer and fall, were 4, 2.41 and 4.03 mg/L and 48.75, 43.79 and 51.07 ?g/L respectively. Seasonal variation indicated that HAAs levels were much higher in spring and fall. PMID:24283403

  1. Transport Membrane Condenser for Water and Energy Recovery from Power Plant Flue Gas

    SciTech Connect

    Dexin Wang

    2012-03-31

    The new waste heat and water recovery technology based on a nanoporous ceramic membrane vapor separation mechanism has been developed for power plant flue gas application. The recovered water vapor and its latent heat from the flue gas can increase the power plant boiler efficiency and reduce water consumption. This report describes the development of the Transport Membrane Condenser (TMC) technology in details for power plant flue gas application. The two-stage TMC design can achieve maximum heat and water recovery based on practical power plant flue gas and cooling water stream conditions. And the report includes: Two-stage TMC water and heat recovery system design based on potential host power plant coal fired flue gas conditions; Membrane performance optimization process based on the flue gas conditions, heat sink conditions, and water and heat transport rate requirement; Pilot-Scale Unit design, fabrication and performance validation test results. Laboratory test results showed the TMC system can exact significant amount of vapor and heat from the flue gases. The recovered water has been tested and proved of good quality, and the impact of SO{sub 2} in the flue gas on the membrane has been evaluated. The TMC pilot-scale system has been field tested with a slip stream of flue gas in a power plant to prove its long term real world operation performance. A TMC scale-up design approach has been investigated and an economic analysis of applying the technology has been performed.

  2. Water uptake efficiency of a maize plant - A simulation case study

    NASA Astrophysics Data System (ADS)

    Meunier, Félicien; Leitner, Daniel; Bodner, Gernot; Javaux, Mathieu; Schnepf, Andrea

    2014-05-01

    Water uptake by plant roots is a complex mechanism controlled by biological and physical properties of the soil-plant-atmosphere system and affects a major component of the water cycle, transpiration. This uptake of water by plants is one of the major factors of plant development. Since water uptake occurs at the roots, root architecture and hydraulic properties both play a crucial role in plant productivity. A fundamental understanding of the main processes of water uptake will enable better breeding of drought resistant plants and the improvement of irrigation strategies. In this work we analyzed the differences of root water uptake between idealized genotypes of a plant using mathematical modelling The numerical simulations were performed by the R-SWMS software (Javaux et al., 2008). The model describes 3-D water movement in soil by solving Richard's equation with a sink term representing root uptake. Water flow within the root xylem network and between soil and root is modelled based on water pressure gradients and calculated according to Doussan's model. The sink term is calculated by integration of local uptakes within rooted representative elementary volumes of soil. The plant water demand is described by a boundary condition at the base of the shoot. We compare the water uptake efficiency of three types of root system architectures of a maize plant. Two are actual architectures from genotypes showing significant differences regarding the internodal distance, the root growth rate and the insertion angle of their primary roots. The third one is an ideotype according to Lynch of the maize plant designed to perform better in one dry environment. We generated with RootBox five repetitions of these three root systems with the same total root volume and simulated two drought scenarios at the flowering stage (lack of water at the top or at the bottom of the soil domain). We did these simulations for two distinct distributions of local conductivities of root segments based on literature values. This numerical experiment shows significantly different behaviors of the root systems in terms of dynamics of the water uptake, duration of the water stress or cumulative transpiration. The ranking of the maize architectures varied according to the considered drought scenario. The performance of a root system depends on the environment and on its hydraulic architecture suggesting that we always need to take the genotype-environment interaction into account for recommending breeding options. This study also shows that an ideotype must be built for one specific environment: the one we created experienced difficulties to transpire when placed in different conditions it has been designed for. By mathematical simulation we increased the understanding of the most important underlying processes governing water uptake in a root system.

  3. COMMUNITY RESPIRATION OF DECOMPOSING PLANTS IN OREGON ESTUARINE MARSHES

    EPA Science Inventory

    Community respiration rates in air and water were measured as indicators of the decomposition rate of dead plant tissue from nine stands of plants in two Oregon estuarine marshes. Respiration rates were low and relatively constant from November to February; during warmer periods ...

  4. Plant water use efficiency over geological time--evolution of leaf stomata configurations affecting plant gas exchange.

    PubMed

    Assouline, Shmuel; Or, Dani

    2013-01-01

    Plant gas exchange is a key process shaping global hydrological and carbon cycles and is often characterized by plant water use efficiency (WUE - the ratio of CO2 gain to water vapor loss). Plant fossil record suggests that plant adaptation to changing atmospheric CO2 involved correlated evolution of stomata density (d) and size (s), and related maximal aperture, amax . We interpreted the fossil record of s and d correlated evolution during the Phanerozoic to quantify impacts on gas conductance affecting plant transpiration, E, and CO2 uptake, A, independently, and consequently, on plant WUE. A shift in stomata configuration from large s-low d to small s-high d in response to decreasing atmospheric CO2 resulted in large changes in plant gas exchange characteristics. The relationships between gas conductance, gws , A and E and maximal relative transpiring leaf area, (amax ?d), exhibited hysteretic-like behavior. The new WUE trend derived from independent estimates of A and E differs from established WUE-CO2 trends for atmospheric CO2 concentrations exceeding 1,200 ppm. In contrast with a nearly-linear decrease in WUE with decreasing CO2 obtained by standard methods, the newly estimated WUE trend exhibits remarkably stable values for an extended geologic period during which atmospheric CO2 dropped from 3,500 to 1,200 ppm. Pending additional tests, the findings may affect projected impacts of increased atmospheric CO2 on components of the global hydrological cycle. PMID:23844085

  5. [Coordination effect between vapor water loss through plant stomata and liquid water supply in soil-plant-atmosphere continuum (SPAC): a review].

    PubMed

    Liu, Li-Min; Qi, Hua; Luo, Xin-Lan; Zhang, Xuan

    2008-09-01

    Some important phenomena and behaviors concerned with the coordination effect between vapor water loss through plant stomata and liquid water supply in SPAC were discussed in this paper. A large amount of research results showed that plants show isohydric behavior when the plant hydraulic and chemical signals cooperate to promote the stomatal regulation of leaf water potential. The feedback response of stomata to the change of environmental humidity could be used to explain the midday depression of stomatal conductance and photosynthesis under drought condition, and also, to interpret the correlation between stomatal conductance and hydraulic conductance. The feed-forward response of stomata to the change of environmental humidity could be used to explain the hysteresis response of stomatal conductance to leaf-atmosphere vapor pressure deficit. The strategy for getting the most of xylem transport requires the rapid stomatal responses to avoid excess cavitation and the corresponding mechanisms for reversal of cavitation in short time. PMID:19102325

  6. Operating boundaries of full-scale advanced water reuse treatment plants: many lessons learned from pilot plant experience.

    PubMed

    Bele, C; Kumar, Y; Walker, T; Poussade, Y; Zavlanos, V

    2010-01-01

    Three Advanced Water Treatment Plants (AWTP) have recently been built in South East Queensland as part of the Western Corridor Recycled Water Project (WCRWP) producing Purified Recycled Water from secondary treated waste water for the purpose of indirect potable reuse. At Luggage Point, a demonstration plant was primarily operated by the design team for design verification. The investigation program was then extended so that the operating team could investigate possible process optimisation, and operation flexibility. Extending the demonstration plant investigation program enabled monitoring of the long term performance of the microfiltration and reverse osmosis membranes, which did not appear to foul even after more than a year of operation. The investigation primarily identified several ways to optimise the process. It highlighted areas of risk for treated water quality, such as total nitrogen. Ample and rapid swings of salinity from 850 to 3,000 mg/l-TDS were predicted to affect the RO process day-to-day operation and monitoring. Most of the setpoints used for monitoring under HACCP were determined during the pilot plant trials. PMID:20935373

  7. On the flow and water quality in the Tokyo Bay including effect of cooling water for the Power Generating Plant

    NASA Astrophysics Data System (ADS)

    Kitahara, Kouichi; Wada, Akira; Uehara, Yoshikazu; Fukuoka, Ippei; Kawanaga, Mitsuhito; Takano, Tairyu

    Driving forces of seawater current in the Tokyo Bay have several factors including the tide, the density structure, the river inflow and others. On the other hand, many power plants of total output of 185.4 MW (as of 1995) are located along the coast of the bay, together with a large number of factors which load the sea area with cooling water and heat. Although these facilities might be considered to affect water current in the bay, few studies have been made on the effects which these artificial inputs may exert on water current. The present study reports computation results, using a 3-dimentional current model on effects of water intake and effluent by a possibly increasing number of power plants on the current in the bay. It was concluded that an additional power plant output of 103.1 MW (corresponding to increase of cooling water by 30% and of heat load by 20% from the present levels) might bring about only slight changes except for altered water current and temperature in the vicinities of power plants of which power output were increased. Average temperature rise of 0.1 °C was also predicted in the surface water throughout the bay.

  8. Aalborg Universitet Plant-wide Control for Better De-oiling of Produced Water in Offshore Oil & Gas

    E-print Network

    Yang, Zhenyu

    Aalborg Universitet Plant-wide Control for Better De-oiling of Produced Water in Offshore Oil &, B. (2013). Plant-wide Control for Better De-oiling of Produced Water in Offshore Oil & Gas.aau.dk on: juli 07, 2015 #12;Plant-wide Control for Better De-oiling of Produced Water in Offshore Oil & Gas

  9. Paraheliotropism can protect water-stressed bean (Phaseolus vulgaris L.) plants against photoinhibition.

    PubMed

    Pastenes, Claudio; Porter, Victor; Baginsky, Cecilia; Horton, Peter; González, Javiera

    2004-12-01

    In order to estimate the importance of leaf movements on photosynthesis in well-watered and water-stressed field grown bean cultivars (Arroz Tuscola (AT), Orfeo INIA (OI), Bayos Titan (BT), and Hallados Dorado (HD)), CO2 assimilation, leaf temperature, and capacity for the maximum quantum yield recovery, measured as Fv/Fm, were assessed. Leaf water potential was lower in water-stressed compared to control plants throughout the day. Water status determined a decrease in the CO2 assimilation and stomatal conductance as light intensity and temperature increased up to maximal intensities at midday. Both parameters were lower in stressed compared to control plants. Even though high light intensity and water-stress induced stomatal closure is regarded as a photoinhibitory condition, the recovery of variable to maximal fluorescence (Fv/Fm) after 30min of darkness was nearly constant in both water regimes. In fact, higher values were observed in OI and AT when under stress. Photochemical and non-photochemical fluorescence quenching resulted in minor changes during the day and were similar between watered and stressed plants. It is concluded that paraheliotropism, present in the four bean cultivars, efficiently protects stressed plants from photoinhibition in the field and helps maintain leaf temperatures far below the ambient temperatures, however, it may also be responsible for low CO2 assimilation rates in watered plants. PMID:15658802

  10. Reducing water freshwater consumption at coal-fired power plants : approaches used outside the United States.

    SciTech Connect

    Elcock, D.

    2011-05-09

    Coal-fired power plants consume huge quantities of water, and in some water-stressed areas, power plants compete with other users for limited supplies. Extensive use of coal to generate electricity is projected to continue for many years. Faced with increasing power demands and questionable future supplies, industries and governments are seeking ways to reduce freshwater consumption at coal-fired power plants. As the United States investigates various freshwater savings approaches (e.g., the use of alternative water sources), other countries are also researching and implementing approaches to address similar - and in many cases, more challenging - water supply and demand issues. Information about these non-U.S. approaches can be used to help direct near- and mid-term water-consumption research and development (R&D) activities in the United States. This report summarizes the research, development, and deployment (RD&D) status of several approaches used for reducing freshwater consumption by coal-fired power plants in other countries, many of which could be applied, or applied more aggressively, at coal-fired power plants in the United States. Information contained in this report is derived from literature and Internet searches, in some cases supplemented by communication with the researchers, authors, or equipment providers. Because there are few technical, peer-reviewed articles on this topic, much of the information in this report comes from the trade press and other non-peer-reviewed references. Reducing freshwater consumption at coal-fired power plants can occur directly or indirectly. Direct approaches are aimed specifically at reducing water consumption, and they include dry cooling, dry bottom ash handling, low-water-consuming emissions-control technologies, water metering and monitoring, reclaiming water from in-plant operations (e.g., recovery of cooling tower water for boiler makeup water, reclaiming water from flue gas desulfurization [FGD] systems), and desalination. Some of the direct approaches, such as dry air cooling, desalination, and recovery of cooling tower water for boiler makeup water, are costly and are deployed primarily in countries with severe water shortages, such as China, Australia, and South Africa. Table 1 shows drivers and approaches for reducing freshwater consumption in several countries outside the United States. Indirect approaches reduce water consumption while meeting other objectives, such as improving plant efficiency. Plants with higher efficiencies use less energy to produce electricity, and because the greater the energy production, the greater the cooling water needs, increased efficiency will help reduce water consumption. Approaches for improving efficiency (and for indirectly reducing water consumption) include increasing the operating steam parameters (temperature and pressure); using more efficient coal-fired technologies such as cogeneration, IGCC, and direct firing of gas turbines with coal; replacing or retrofitting existing inefficient plants to make them more efficient; installing high-performance monitoring and process controls; and coal drying. The motivations for increasing power plant efficiency outside the United States (and indirectly reducing water consumption) include the following: (1) countries that agreed to reduce carbon emissions (by ratifying the Kyoto protocol) find that one of the most effective ways to do so is to improve plant efficiency; (2) countries that import fuel (e.g., Japan) need highly efficient plants to compensate for higher coal costs; (3) countries with particularly large and growing energy demands, such as China and India, need large, efficient plants; (4) countries with large supplies of low-rank coals, such as Germany, need efficient processes to use such low-energy coals. Some countries have policies that encourage or mandate reduced water consumption - either directly or indirectly. For example, the European Union encourages increased efficiency through its cogeneration directive, which requires member states to assess their

  11. Modeling terrestrial carbon and water dynamics across climatic gradients: does plant trait diversity matter?

    PubMed

    Pappas, Christoforos; Fatichi, Simone; Burlando, Paolo

    2016-01-01

    Plant trait diversity in many vegetation models is crudely represented using a discrete classification of a handful of 'plant types' (named plant functional types; PFTs). The parameterization of PFTs reflects mean properties of observed plant traits over broad categories ignoring most of the inter- and intraspecific plant trait variability. Taking advantage of a multivariate leaf-trait distribution (leaf economics spectrum), as well as documented plant drought strategies, we generate an ensemble of hypothetical species with coordinated attributes, rather than using few PFTs. The behavior of these proxy species is tested using a mechanistic ecohydrological model that translates plant traits into plant performance. Simulations are carried out for a range of climates representative of different elevations and wetness conditions in the European Alps. Using this framework we investigate the sensitivity of ecosystem response to plant trait diversity and compare it with the sensitivity to climate variability. Plant trait diversity leads to highly divergent vegetation carbon dynamics (fluxes and pools) and to a lesser extent water fluxes (transpiration). Abiotic variables, such as soil water content and evaporation, are only marginally affected. These results highlight the need for revising the representation of plant attributes in vegetation models. Probabilistic approaches, based on observed multivariate whole-plant trait distributions, provide a viable alternative. PMID:26389742

  12. Water balance altered in cucumber plants infected with Fusarium oxysporum f. sp. cucumerinum

    PubMed Central

    Wang, Min; Sun, Yuming; Sun, Guomei; Liu, Xiaokang; Zhai, Luchong; Shen, Qirong; Guo, Shiwei

    2015-01-01

    Fusarium wilt is caused by the infection and growth of the fungus Fusarium oxysporum in the xylem of host plants. The physiological responses of cucumbers that are infected with Fusarium oxysporum f. sp. cucumerinum (FOC) was studied in pot and hydroponic experiments in a greenhouse. The results showed that although water absorption and stem hydraulic conductance decreased markedly in infected plants, large amounts of red ink accumulated in the leaves of infected cucumber plants. The transpiration rate (E) and stomatal conductance (gs) of the infected plants were significantly reduced, but the E/gs was higher than healthy plants. We further found that there was a positive correlation between leaf membrane injury and E/gs, indicating that the leaf cell membrane injury increased the non-stomatal water loss from infected plants. The fusaric acid (FA), which was detected in the infected plant, resulted in damage to the leaf cell membranes and an increase in E/gs, suggesting that FA plays an important role in non-stomatal water loss. In conclusion, leaf cell membrane injury in the soil-borne Fusarium wilt of cucumber plants induced uncontrolled water loss from damaged cells. FA plays a critical role in accelerating the development of Fusarium wilt in cucumber plants. PMID:25579504

  13. Water balance altered in cucumber plants infected with Fusarium oxysporum f. sp. cucumerinum.

    PubMed

    Wang, Min; Sun, Yuming; Sun, Guomei; Liu, Xiaokang; Zhai, Luchong; Shen, Qirong; Guo, Shiwei

    2015-01-01

    Fusarium wilt is caused by the infection and growth of the fungus Fusarium oxysporum in the xylem of host plants. The physiological responses of cucumbers that are infected with Fusarium oxysporum f. sp. cucumerinum (FOC) was studied in pot and hydroponic experiments in a greenhouse. The results showed that although water absorption and stem hydraulic conductance decreased markedly in infected plants, large amounts of red ink accumulated in the leaves of infected cucumber plants. The transpiration rate (E) and stomatal conductance (gs) of the infected plants were significantly reduced, but the E/gs was higher than healthy plants. We further found that there was a positive correlation between leaf membrane injury and E/gs, indicating that the leaf cell membrane injury increased the non-stomatal water loss from infected plants. The fusaric acid (FA), which was detected in the infected plant, resulted in damage to the leaf cell membranes and an increase in E/gs, suggesting that FA plays an important role in non-stomatal water loss. In conclusion, leaf cell membrane injury in the soil-borne Fusarium wilt of cucumber plants induced uncontrolled water loss from damaged cells. FA plays a critical role in accelerating the development of Fusarium wilt in cucumber plants. PMID:25579504

  14. INVESTIGATIONS INTO THE GC/MS DECOMPOSITION OF TRIBROMONITROMETHANE IN DRINKING WATER DISINFECTION BY-PRODUCT ANALYSIS

    EPA Science Inventory

    Tribromonitromethane (bromopicrin) has been found to be a disinfection by-product (DBP) in
    chlorinated1 and ozonated2 drinking water, and is structurally similar to dibromonitromethane,
    which has been indicated through structural analysis to be a possible carcinogen. Bromop...

  15. Physiological, anatomical and leaf hydraulic effects on leaf water ?18O enrichment in different plant species

    NASA Astrophysics Data System (ADS)

    Kahmen, A.; Arndt, S. K.; Dawson, T. E.

    2007-12-01

    Stable oxygen isotope ratios (?18O) of plant and source waters are valuable tools in the analysis of water and carbon fluxes at leaf, plant, and ecosystem scales. Recent improvements in mechanistic models have significantly advanced the understanding of isotopic leaf water enrichment, which is an important source of ?18O variability in plants and ecosystems. However, the marked variability in leaf water ?18O values that have been reported for different plant species hampers efforts to interpret and then apply data on leaf water ?18O values for studies conducted at the ecosystem scale. To improve the understanding and application of ?18O values in leaf water, we tested the interplay of physiological, morphological, anatomical and leaf hydraulic properties as drivers of leaf water ?18O values across 17 Eucalyptus species growing in a common garden. We observed large differences in leaf water ?18O across the 17 species. These differences were only partly driven by physiological and leaf morphological differences across species. A sensitivity analysis using state-of-the-art leaf water enrichment models showed that the parameter - effective path length - (L) is of critical importance for the variability of leaf water ?18O across different species. The data show that L can be related to a suite of leaf properties that include physiology, anatomy and hydraulics. Consequently, consideration of leaf properties will significantly improve the interpretation of ?18O values in leaf water across different plant species and will therefore help in the application of ?18O values in carbon and water cycle assessments at both the plant and the ecosystem scale.

  16. Newly observed several peroxides from the gas phase ozonolysis of isoprene using a flow tube reactor and the water vapor effect on their formation and decomposition

    NASA Astrophysics Data System (ADS)

    Huang, D.; Chen, Z.; Zhao, Y.

    2012-12-01

    In recent years, one has been paying more and more attention to the formation of hydrogen peroxide and organic peroxides in the oxidation of volatile organic compounds (VOCs) because peroxides play important roles, such as reservoir of OH, HO2 and RO2 radicals, intermediate of Criegee radical chemistry and contributor to secondary organic aerosol. However, to the best of our knowledge, in the reaction of ozone with VOCs, only several small peroxides such as hydrogen peroxide (H2O2), hydroxymethyl hydroperoxide (HMHP), and methyl hydroperoxide (MHP) were separately identified, and their yields varied widely between different studies. Moreover, the information on the formation mechanism of peroxides in the ozonolysis of VOCs was mostly from a speculation rather than experimental evidence. Notably, a static chamber was employed in most of the previous studies, potentially resulting in the decomposition and heterogeneous reaction of peroxides on the chamber walls within an experiment time of tens of minutes to several hours, and possibly missing the details about the generation of peroxides. In the present study, we have used a flow quartz tube reactor to investigate the formation of peroxides in the ozonolysis of isoprene at various relative humidities (RH). A variety of peroxides have been detected on the tens of seconds of time scale using an online high performance liquid chromatography coupled with post-column derivatization using p-hydroxyphenylacetic acid and fluorescence detection. Our experimental results show that in addition to the three peroxides mentioned previously, more four ones, those are peroxyacetic acid (PAA) and three unknown peroxides, have been found. Furthermore, the total yield of the three small peroxides (H2O2, HMHP and MHP) is found to be similar to the result of literature; while for PAA and three unknown peroxides, they highlight a combined molar yield, for example, ~ 40% at 5% RH, much higher than that of the three small peroxides. Opposite to the previous conclusion that the peroxide yield would be positively correlated with RH, the yields of PAA and three unknown peroxides detected in the present study decreased with the RH increase. We tentatively assign these unknown peroxides to be hydroxyl hydroperoxides, which are produced by the reaction of different Criegee radicals with water. We used a box model coupled with the MCM v3.2 mechanism to simulate the reaction processes of the ozone-initiated oxidation of isoprene, adding the reaction between the gaseous water (and water dimer) and Criegee radicals and the decomposition of water-assisted hydroxyl hydroperoxides. We find that this modified mechanism would better explain the variation of peroxides with the RH increase, implying that molecular water and water cluster should be involved in the production and removal of peroxides in the future model.

  17. Toxicity tests of effluents with marsh plants in water and sediment

    SciTech Connect

    Walsh, G.E.; Weber, D.E.; Simon, T.L.; Brashers, L.K.

    1991-01-01

    Methods are described for toxicity testing of water and sediment with two varieties of the freshwater marsh plant Echinochloa crusgalli (Linneaus) Palisot de Beauvois (Poaceae), and complex effluents. Two tests are described: a seed germination and early seedling growth test in water, and a survival and seedling growth test in natural and synthetic sediments. Effects of effluents from a sewage treatment plant, tannery, textile mill, pulp and paper mill, coking plant and sewage treatment plant included inhibition of germination, chlorophyll synthesis and growth. The tests with rooted marsh plants were sensitive to pollutants and detected toxicity of a range of pollutants in water and sediment. Synthetic sediments similar to natural sediments allowed toxicity tests to be done under carefully controlled conditions of particle size distribution, organic content, pH, electrode potential (Eh) and cation exchange capacity (CEC).

  18. Seismicity and seismic response of the Soviet-designed VVER (Water-cooled, Water moderated Energy Reactor) reactor plants

    SciTech Connect

    Ma, D.C.; Gvildys, J.; Wang, C.Y.; Spencer, B.W.; Sienicki, J.J.; Seidensticker, R.W.; Purvis, E.E. III

    1989-01-01

    On March 4, 1977, a strong earthquake occurred at Vrancea, Romania, about 350 km from the Kozloduy plant in Bulgaria. Subsequent to this event, construction of the unit 2 of the Armenia plant was delayed over two years while seismic features were added. On December 7, 1988, another strong earthquake struck northwest Armenia about 90 km north of the Armenia plant. Extensive damage of residential and industrial facilities occurred in the vicinity of the epicenter. The earthquake did not damage the Armenia plant. Following this event, the Soviet government announced that the plant would be shutdown permanently by March 18, 1989, and the station converted to a fossil-fired plant. This paper presents the results of the seismic analyses of the Soviet-designed VVER (Water-cooled, Water moderated Energy Reactor) plants. Also presented is the information concerning seismicity in the regions where VVERs are located and information on seismic design of VVERs. The reference units are the VVER-440 model V230 (similar to the two units of the Armenia plant) and the VVER-1000 model V320 units at Kozloduy in Bulgaria. This document provides an initial basis for understanding the seismicity and seismic response of VVERs under seismic events. 1 ref., 9 figs., 3 tabs.

  19. Water management requirements for animal and plant maintenance on the Space Station

    NASA Technical Reports Server (NTRS)

    Johnson, C. C.; Rasmussen, D.; Curran, G.

    1987-01-01

    Long-duration Space Station experiments that use animals and plants as test specimens will require increased automation and advanced technologies for water management in order to free scientist-astronauts from routine but time-consuming housekeeping tasks. The three areas that have been identified as requiring water management and that are discusseed are: (1) drinking water and humidity condensate of the animals, (2) nutrient solution and transpired water of the plants, and (3) habitat cleaning methods. Automation potential, technology assessment, crew time savings, and resupply penalties are also discussed.

  20. Assessment of light water reactor power plant cost and ultra-acceleration depreciation financing

    E-print Network

    El-Magboub, Sadek Abdulhafid.

    Although in many regions of the U.S. the least expensive electricity is generated from light-water reactor (LWR) plants, the fixed (capital plus operation and maintenance) cost has increased to the level where the cost ...

  1. COMETABOLISM OF TRIHALOMETHANES BY NITRIFYING BIOFILTERS UNDER DRINKING WATER TREATMENT PLANT CONDITIONS

    EPA Science Inventory

    EPA Identifier: FP916412
    Title: Cometabolism of Trihalomethanes by Nitrifying Biofilters Under Drinking Water Treatment Plant Conditions
    Fellow (Principal Investigator): David G. Wahman
    Institution: University of Texas at Austin
    EPA ...

  2. Water Treatment Plant Sludges--An Update of the State of the Art: Part 2.

    ERIC Educational Resources Information Center

    American Water Works Association Journal, 1978

    1978-01-01

    This report outlines the state of the art with respect to nonmechanical and mechanical methods of dewatering water treatment plant sludge, ultimate solids disposal, and research and development needs. (CS)

  3. Water/Wastewater Treatment Plant Field Device Wiring Method Decision Analysis

    E-print Network

    Dicus, Scott C.

    2011-12-16

    The choice of field device wiring method for water and wastewater treatment plant design is extremely complex and contains many variables. The choice not only affects short-term startup and equipment costs, but also long-term operations...

  4. Removal of hormones and pharmaceuticals in the Advanced Water Recycling Demonstration Plant in Queensland, Australia 

    E-print Network

    Khan, S.J.; Wintgens, T.; Sherman, P.; Zaricky, J.; Schäfer, Andrea

    2004-01-01

    An advanced water recycling demonstration plant was employed to investigate the effectiveness of a number of treatment technologies in the removal of some residuals of commonly prescribed pharmaceuticals as well as ...

  5. Institutional impediments to using alternative water sources in thermoelectric power plants.

    SciTech Connect

    Elcock, D.

    2011-08-03

    This report was funded by the U.S. Department of Energy's (DOE's) National Energy Technology Laboratory (NETL) Existing Plants Research Program, which has an energy-water research effort that focuses on water use at power plants. This study complements the Existing Plants Research Program's overall research effort by evaluating water issues that could impact power plants. Obtaining adequate water supplies for cooling and other operations at a reasonable cost is a key factor in siting new and maintaining existing thermoelectric power plant operations. One way to reduce freshwater consumption is to use alternative water sources such as reclaimed (or recycled) water, mine pool water, and other nontraditional sources. The use of these alternative sources can pose institutional challenges that can cause schedule delays, increase costs, or even require plants to abandon their plans to use alternative sources. This report identifies and describes a variety of institutional challenges experienced by power plant owners and operators across the country, and for many of these challenges it identifies potential mitigating approaches. The information comes from publically available sources and from conversations with power plant owners/operators familiar with using alternative sources. Institutional challenges identified in this investigation include, but are not limited to, the following: (1) Institutional actions and decisions that are beyond the control of the power plant. Such actions can include changes in local administrative policies that can affect the use of reclaimed water, inaccurate growth projections regarding the amount of water that will be available when needed, and agency workloads and other priorities that can cause delays in the permitting and approval processes. (2) Developing, cultivating, and maintaining institutional relationships with the purveyor(s) of the alternative water source, typically a municipal wastewater treatment plant (WWTP), and with the local political organizations that can influence decisions regarding the use of the alternative source. Often a plan to use reclaimed water will work only if local politics and power plant goals converge. Even then, lengthy negotiations are often needed for the plans to come to fruition. (3) Regulatory requirements for planning and developing associated infrastructure such as pipelines, storage facilities, and back-up supplies that can require numerous approvals, permits, and public participation, all of which can create delays and increased costs. (4) Permitting requirements that may be difficult to meet, such as load-based discharge limits for wastewater or air emissions limitations for particulate matter (which will be in the mist of cooling towers that use reclaimed water high in dissolved solids). (5) Finding discharge options for cooling tower blowdown of reclaimed water that are acceptable to permitting authorities. Constituents in this wastewater can limit options for discharge. For example, discharge to rivers requires National Pollutant Discharge Elimination System (NPDES) permits whose limits may be difficult to meet, and underground injection can be limited because many potential injection sites have already been claimed for disposal of produced waters from oil and gas wells or waters associated with gas shale extraction. (6) Potential liabilities associated with using alternative sources. A power plant can be liable for damages associated with leaks from reclaimed water conveyance systems or storage areas, or with mine water that has been contaminated by unscrupulous drillers that is subsequently discharged by the power plant. (7) Community concerns that include, but are not limited to, increased saltwater drift on farmers fields; the possibility that the reclaimed water will contaminate local drinking water aquifers; determining the 'best' use of WWTP effluent; and potential health concerns associated with emissions from the cooling towers that use recycled water. (8) Interveners that raise public concerns about the potential for emissions of emergi

  6. Electrophysiological assessment of water stress in fruit-bearing woody plants.

    PubMed

    Ríos-Rojas, Liliana; Tapia, Franco; Gurovich, Luis A

    2014-06-15

    Development and evaluation of a real-time plant water stress sensor, based on the electrophysiological behavior of fruit-bearing woody plants is presented. Continuous electric potentials are measured in tree trunks for different irrigation schedules, inducing variable water stress conditions; results are discussed in relation to soil water content and micro-atmospheric evaporative demand, determined continuously by conventional sensors, correlating this information with tree electric potential measurements. Systematic and differentiable patterns of electric potentials for water-stressed and no-stressed trees in 2 fruit species are presented. Early detection and recovery dynamics of water stress conditions can also be monitored with these electrophysiology sensors, which enable continuous and non-destructive measurements for efficient irrigation scheduling throughout the year. The experiment is developed under controlled conditions, in Faraday cages located at a greenhouse area, both in Persea americana and Prunus domestica plants. Soil moisture evolution is controlled using capacitance sensors and solar radiation, temperature, relative humidity, wind intensity and direction are continuously registered with accurate weather sensors, in a micro-agrometeorological automatic station located at the experimental site. The electrophysiological sensor has two stainless steel electrodes (measuring/reference), inserted on the stem; a high precision Keithley 2701 digital multimeter is used to measure plant electrical signals; an algorithm written in MatLab(®), allows correlating the signal to environmental variables. An electric cyclic behavior is observed (circadian cycle) in the experimental plants. For non-irrigated plants, the electrical signal shows a time positive slope and then, a negative slope after restarting irrigation throughout a rather extended recovery process, before reaching a stable electrical signal with zero slope. Well-watered plants presented a continuous signal with daily maximum and a minimum EP of similar magnitude in time, with zero slope. This plant electrical behavior is proposed for the development of a sensor measuring real-time plant water status. PMID:24877671

  7. IMPACTS OF COAL-FIRED POWER PLANTS ON LOCAL GROUND-WATER SYSTEMS: WISCONSIN POWER PLANT IMPACT STUDY

    EPA Science Inventory

    Quantitative techniques for simulating the impacts of a coal-fired power plant on the ground-water system of a river flood-plain wetland were developed and tested. Effects related to the construction and operation of the cooling lake and ashpit had the greatest impact. Ground-wat...

  8. The impact of extreme precipitation on plant growth and water relations

    NASA Astrophysics Data System (ADS)

    Zeppel, M.; Lehmann, C.; Lewis, J. D.; Medlyn, B. E.

    2012-12-01

    Background The global hydrological cycle is predicted to become more intense, or extreme in future climates, with both larger precipitation events and longer times between events. The resulting wide fluctuations in soil water content (long droughts followed by flooding) may dramatically affect terrestrial ecosystems. Although effects of drought are well studied, tree responses to changed timing of precipitation are mostly unknown. Further, in future extreme precipitation is likely to occur in conjunction with elevated atmospheric CO2 concentrations [CO2]. We tested the impact of extreme precipitation and elevated [CO2] on plant growth and water relations. Methods/results Ten Acacia auriculiformis and Eucalyptus tetradonta saplings were grown in glasshouses, with ambient (380 p.p.m.) and elevated (600 p.p.m.) [CO2] and subject to ambient (1L weekly) and extreme (2L fortnightly) watering conditions (four treatments). We tested whether: (1) plants would show differential water stress and growth under extreme precipitation compared with ambient water treatments; and (2) plants would show differential water stress and growth responses under elevated compared with ambient [CO2] treatments. We found that the extreme precipitation, compared to ambient precipitation, lead to more water stressed plants, with more negative leaf water potential and lower stomatal conductance in both species. Further, plants experiencing extreme precipitation had a higher proportion of root volume at depth within the Eucalyptus. In contrast, the root depth of Acacia was similar across all treatments. Leaf area was smaller in extreme precipitation compared with ambient for Acacias, whereas leaf area was comparable across watering treatments in Eucalypts. Elevated CO2 had no impact on leaf water potential, stomatal conductance during the day or proportion of root depth. The Acacia, from tropical dry forest ecosystems, showed more signs of water stress (more negative leaf water potential and lower stomatal conductance) than the Eucalyptus, from savanna ecosystems. This suggests Eucalyptus saplings may tolerate water stress imposed by extreme precipitation better than Acacias, perhaps influencing community structure in tropical ecosystems.

  9. COOLING WATER ISSUES AND OPPORTUNITIES AT U.S. NUCLEAR POWER PLANTS

    SciTech Connect

    Gary Vine

    2010-12-01

    This report has been prepared for the Department of Energy, Office of Nuclear Energy (DOE-NE), for the purpose of providing a status report on the challenges and opportunities facing the U.S. commercial nuclear energy industry in the area of plant cooling water supply. The report was prompted in part by recent Second Circuit and Supreme Court decisions regarding cooling water system designs at existing thermo-electric power generating facilities in the U.S. (primarily fossil and nuclear plants). At issue in the courts have been Environmental Protection Agency regulations that define what constitutes “Best Technology Available” for intake structures that withdraw cooling water that is used to transfer and reject heat from the plant’s steam turbine via cooling water systems, while minimizing environmental impacts on aquatic life in nearby water bodies used to supply that cooling water. The report was also prompted by a growing recognition that cooling water availability and societal use conflicts are emerging as strategic energy and environmental issues, and that research and development (R&D) solutions to emerging water shortage issues are needed. In particular, cooling water availability is an important consideration in siting decisions for new nuclear power plants, and is an under-acknowledged issue in evaluating the pros and cons of retrofitting cooling towers at existing nuclear plants. Because of the significant ongoing research on water issues already being performed by industry, the national laboratories and other entities, this report relies heavily on ongoing work. In particular, this report has relied on collaboration with the Electric Power Research Institute (EPRI), including its recent work in the area of EPA regulations governing intake structures in thermoelectric cooling water systems.

  10. Reuse of process water in a waste-to-energy plant: An Italian case of study.

    PubMed

    Gardoni, Davide; Catenacci, Arianna; Antonelli, Manuela

    2015-09-01

    The minimisation of water consumption in waste-to-energy (WtE) plants is an outstanding issue, especially in those regions where water supply is critical and withdrawals come from municipal waterworks. Among the various possible solutions, the most general, simple and effective one is the reuse of process water. This paper discusses the effectiveness of two different reuse options in an Italian WtE plant, starting from the analytical characterisation and the flow-rate measurement of fresh water and process water flows derived from each utility internal to the WtE plant (e.g. cooling, bottom ash quenching, flue gas wet scrubbing). This census allowed identifying the possible direct connections that optimise the reuse scheme, avoiding additional water treatments. The effluent of the physical-chemical wastewater treatment plant (WWTP), located in the WtE plant, was considered not adequate to be directly reused because of the possible deposition of mineral salts and clogging potential associated to residual suspended solids. Nevertheless, to obtain high reduction in water consumption, reverse osmosis should be installed to remove non-metallic ions (Cl(-), SO4(2-)) and residual organic and inorganic pollutants. Two efficient solutions were identified. The first, a simple reuse scheme based on a cascade configuration, allowed 45% reduction in water consumption (from 1.81 to 0.99m(3)tMSW(-1), MSW: Municipal Solid Waste) without specific water treatments. The second solution, a cascade configuration with a recycle based on a reverse osmosis process, allowed 74% reduction in water consumption (from 1.81 to 0.46m(3)tMSW(-1)). The results of the present work show that it is possible to reduce the water consumption, and in turn the wastewater production, reducing at the same time the operating cost of the WtE plant. PMID:26028558

  11. Effects of water pulsing on individual performance and competitive hierarchies in plants

    E-print Network

    Novoplansky, Ariel

    Effects of water pulsing on individual performance and competitive hierarchies in plants and there were significant hierarchies of competitive ability. Under frequent pulses, the fast-growing species plants and ability to tolerate the presence of neighbors. However, under infrequent pulses, the slowest

  12. Nitrogen and water affect direct and indirect plant systemic induced defense in cotton

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We tested the affects of nitrogen levels and water availability on the ability of cotton plants to deter feeding by Spodoptera exigua larvae through induction of anti-feedant chemicals by the cotton plant, and to attract the biological control agent, Micropitis crociepes through induction of chemica...

  13. Limitations to postfire seedling establishment: the role of seeding technology, water availability, and invasive plant abundance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Seeding rangeland following wildfire is a central tool managers use to stabilize soils and inhibit the spread of invasive plants. Rates of successful seeding on arid rangeland, however, are low. The objective of this study was to determine the degree to which water availability, invasive plant abund...

  14. ACCEPTED BY WATER ENVIRONMENT RESEARCH ODOR AND VOC REMOVAL FROM WASTEWATER TREATMENT PLANT

    E-print Network

    ACCEPTED BY WATER ENVIRONMENT RESEARCH _______ ODOR AND VOC REMOVAL FROM WASTEWATER TREATMENT PLANT of biofilters for sequential removal of H2S and VOCs from wastewater treatment plant waste air. The biofilter volatile organic compounds (VOCs) and toxic air pollutants emitted from wastewater and solids handling

  15. Percolated water can leach undesirable chemical compounds below the rooting zone of plants and

    E-print Network

    Percolated water can leach undesirable chemical compounds below the rooting zone of plants for salts and pollutants, the contamination of streams, rivers, lakes, and groundwater resources poses a great threat to plant and animal health, the environment, the economy, and civilization. Further Reading

  16. Influence of Planting Date and Water Management on Reniform Nematode Populations in Cotton

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Planting dates and water management practices were examined for potential impact on reniform nematode (Rotylenchulus reniformis) populations in cotton (Gossypium hirsutum). A field trial conducted in 2005 and 2006 in Stoneville, MS examined the influence of early (April 1) or normal (May 1) planting...

  17. Modeling plant-atmosphere carbon and water fluxes along a CO2 gradient

    Technology Transfer Automated Retrieval System (TEKTRAN)

    At short time scales (hourly to daily), plant photosynthesis and transpiration respond nonlinearly to atmospheric CO2 concentration and vapor pressure deficit, depending on plant water status and thus soil moisture. Modeling vegetation and soil responses to different values of CO2 at multiple time s...

  18. INFLUENCE OF PEROXYACETYL NITRATE (PAN) ON WATER STRESS IN BEAN PLANTS

    EPA Science Inventory

    Bean plants (Phaseolus vulgaris) were exposed to 395 micrograms/cu m (0.08 ppm) peroxyacetyl nitrate (PAN) for 0.5 hr and subjected to drought stress following exposure. PAN influenced the plant water potential of PAN-sensitive 'Provider' resulting in visible wilting and reduced ...

  19. GEOGRAPHIC VARIATION IN NUTRIENT AVAILABILITY, STOICHIOMETRY, AND METAL CONCENTRATIONS OF PLANTS AND PORE-WATER IN

    E-print Network

    Gotelli, Nicholas J.

    AND PORE-WATER IN OMBROTROPHIC BOGS IN NEW ENGLAND, USA Nicholas J. Gotelli1 , Paula J. Mouser2 , Stephen P of nutrient limitation and broad-scale anthropogenic inputs. In 24 rain-fed (ombrotrophic) peatland bogs of three common bog plant genera ­ leather leaf (Chamaedaphne calyculata), northern pitcher plant

  20. WATER RELATIONS OF OBLIGATE RIPARIAN PLANTS AS A FUNCTION OF STREAMFLOW DIVERSION ON THE BISHOP CREEK WATERSHED1

    E-print Network

    Sierra Nevada. Ri- parian plants on diverted reaches had reduced stomatal conductance and water potential on diverted reaches had reduced stomatal conductance and lower midday water potentials relative to surrounding and seasonal patterns of plant water potential, stomatal conductance and transpirational water loss of adults

  1. Responses of wetland plants to effluents in water and sediment

    SciTech Connect

    Walsh, G.E.; Weber, D.E.; Nguyen, M.T.; Esry, L.K.

    1991-01-01

    Responses of two wetland vascular plants, Echinochloa crusgalli and Sesbania macrocarpa, exposed to effluents from a coke plant, a pulp mill, a wastewater treatment plant, and the herbicide, hexazinone, were measured in three types of tests: seed germination and early growth, seedling survival and growth in hydroponic culture, and seedling survival and growth in sand and synthetic sediments with clay, silt, and sand, 3, 5, 7.5, or 10% organic contents. There was no effect of effluents or herbicide on germination and survival was affected only by the herbicide. When compared to controls, growth rates were reduced significantly in all tests except for E. crusgalli exposed to effluent from a wastewater treatment plant. There, the effluent stimulated growth in sediments. Increasing concentrations of organic matter in sediments had little effect on toxicity of effluents, but did cause reduced effects of hexazinone.

  2. Temperature, oxygen, and vegetation controls on decomposition in a James Bay peatland

    NASA Astrophysics Data System (ADS)

    Philben, Michael; Holmquist, James; MacDonald, Glen; Duan, Dandan; Kaiser, Karl; Benner, Ronald

    2015-06-01

    The biochemical composition of a peat core from James Bay Lowland, Canada, was used to assess the extent of peat decomposition and diagenetic alteration. Our goal was to identify environmental controls on peat decomposition, particularly its sensitivity to naturally occurring changes in temperature, oxygen exposure time, and vegetation. All three varied substantially during the last 7000 years, providing a natural experiment for evaluating their effects on decomposition. The bottom 50 cm of the core formed during the Holocene Climatic Optimum (~7000-4000 years B.P.), when mean annual air temperature was likely 1-2°C warmer than present. A reconstruction of the water table level using testate amoebae indicated oxygen exposure time was highest in the subsequent upper portion of the core between 150 and 225 cm depth (from ~2560 to 4210 years B.P.) and the plant community shifted from mostly Sphagnum to vascular plant dominance. Several independent biochemical indices indicated that decomposition was greatest in this interval. Hydrolysable amino acid yields, hydroxyproline yields, and acid:aldehyde ratios of syringyl lignin phenols were higher, while hydrolysable neutral sugar yields and carbon:nitrogen ratios were lower in this zone of both vascular plant vegetation and elevated oxygen exposure time. Thus, peat formed during the Holocene Climatic Optimum did not appear to be more extensively decomposed than peat formed during subsequent cooler periods. Comparison with a core from the West Siberian Lowland, Russia, indicates that oxygen exposure time and vegetation are both important controls on decomposition, while temperature appears to be of secondary importance. The low apparent sensitivity of decomposition to temperature is consistent with recent observations of a positive correlation between peat accumulation rates and mean annual temperature, suggesting that contemporary warming could enhance peatland carbon sequestration, although this could be offset by an increasing contribution of vascular plants to the vegetation.

  3. Plant water use efficiency shapes co-evolution of stomata size and density over geologic time

    NASA Astrophysics Data System (ADS)

    Assouline, S.; Or, D.

    2010-12-01

    The appearance of stomata and formation of impervious leaf cuticle are key elements in terrestrial plant evolution allowing plants to control gaseous diffusion and regulate water loss during simultaneous carbon dioxide uptake. An important plant gaseous diffusion adaptation was achieved by co-evolution of stomata density (D) and maximum aperture size (S), whose product ?=S.D defines the evaporating fraction of the leaf surface and determines gaseous conductance. The plant leaf fossil record reveals significant variations in D and S over the 400 Myrs of the Phanerozoic eon, whose impact on gas-exchange capacity and on plant evolution are not fully understood. Characteristics of evaporation suppression from perforated diffusion barriers deduced from plant fossil record delineate the evolution of ? as atmospheric CO2 declined from 4000 ppm to present day values. Surprisingly, despite non monotonous variations in ? during plant evolution, plant water use efficiency (WUE) has improved systematically during the decrease in atmospheric CO2 over the Phanerozoic, at variance with conventional predictions. The new WUE trend is based on physical relations between ? and evaporation suppression by perforated diffusion barriers, providing new insights on the dominance of water related regulatory function and on consequences of future CO2 enriched atmosphere on plant function and hydrologic cycle such as continental runoff scenarios.

  4. Model development for prediction of soil water dynamics in plant production.

    PubMed

    Hu, Zhengfeng; Jin, Huixia; Zhang, Kefeng

    2015-09-01

    Optimizing water use in agriculture and medicinal plants is crucially important worldwide. Soil sensor-controlled irrigation systems are increasingly becoming available. However it is questionable whether irrigation scheduling based on soil measurements in the top soil could make best use of water for deep-rooted crops. In this study a mechanistic model was employed to investigate water extraction by a deep-rooted cabbage crop from the soil profile throughout crop growth. The model accounts all key processes governing water dynamics in the soil-plant-atmosphere system. Results show that the subsoil provides a significant proportion of the seasonal transpiration, about a third of water transpired over the whole growing season. This suggests that soil water in the entire root zone should be taken into consideration in irrigation scheduling, and for sensor-controlled irrigation systems sensors in the subsoil are essential for detecting soil water status for deep-rooted crops. PMID:26525032

  5. Comparison of trace metals in the intake and discharge water of power plants using "clean" techniques.

    PubMed

    Salvito, D T; Allen, H E; Parkhurst, B R; Warren-Hicks, W J

    2001-01-01

    Once-through, noncontact condenser cooling water at power plants is frequently discharged back to the fresh or saline water body used for its intake water. This study evaluated the potential effect that trace metals, collected using "clean" sampling and analytical techniques and discharged from a once-through, noncontact cooling water system from a power plant, have on receiving water bodies. A paired t-test was used to compare the intake and discharge concentrations of the metals. The metals analyzed were antimony, arsenic, barium, beryllium, boron, cadmium, chromium, copper, lead, mercury, nickel, selenium, silver, thallium, and zinc. "Clean" is a term applied to field and analytical procedures that are designed to reduce or eliminate ubiquitous metal contamination from samples collected for environmental monitoring. Study results indicate that there is no measurable difference between intake and discharge samples from a noncontact cooling water system, and, therefore, there is no net contribution of metals to receiving water bodies from this system. PMID:11558298

  6. Water Source Utilization of Hammock and Pine Rockland Plant Communities in the Everglades, USA.

    NASA Astrophysics Data System (ADS)

    Saha, A. K.; Sternberg, L.; Miralles-Wilhelm, F.

    2007-12-01

    South Florida has a mosaic of plant communities resulting from topographical differences, spatially varying hydroperiods and fire. The only plant communities not flooded in the wet season are hardwood hammocks and often pine rocklands. Natural fires burn off litter accumulated in pine rocklands, with the exception of organic matter in sinkholes in the limestone bedrock. This relative lack of soil is thought to constrain pineland plants in the Everglades to depend upon groundwater that is typically low in nutrients. In contrast, adjoining hardwood hammocks have accumulated an organic soil layer that traps rainwater and nutrients. Plants in hammocks may be able to utilize this water and thereby access nutrients present in the litter. Hammocks are thus viewed as localized areas of high nutrients and instances of vegetation feedback upon the oligotrophic everglades landscape enabling establishment and survival of flood-intolerant tropical hardwood species. This study examines water source use and couples it to foliar nutrient concentrations of plants found in hammocks and pinelands. We examined the ?2H and ?18O of stem waters in plants in Everglades National Park and compared those with the ?2H and ?18O of potential water sources. In the wet season hammock plants accessed both groundwater and water in the surface organic soil layer while in the dry season they relied more on groundwater. A similar seasonal shift was observed in pineland plants; however groundwater constituted a much higher proportion of total water uptake throughout the year under observation. Concomitant with differential water utilization by hammock and pineland plant communities, we observed hammock plants having a significantly higher annual mean foliar N and P concentration than pineland plants. Most hammock species are intolerant of flooded soils and are thus constrained by the high water table in the wet season, yet access the lowered groundwater table in the dry season due to drying up of surface soilwater. This dependence on a relatively narrow seasonal range of water table depth has important implications for South Florida water resource management that can affect these ecologically important upland communities in the Everglades. Being the only emergent areas in the wet season, hammocks provide habitat for a wide range of flora and fauna.

  7. Occurrence and elimination of cyanobacterial toxins in drinking water treatment plants

    SciTech Connect

    Hoeger, Stefan J.; Hitzfeld, Bettina C.; Dietrich, Daniel R

    2005-03-15

    Toxin-producing cyanobacteria (blue-green algae) are abundant in surface waters used as drinking water resources. The toxicity of one group of these toxins, the microcystins, and their presence in surface waters used for drinking water production has prompted the World Health Organization (WHO) to publish a provisional guideline value of 1.0 {mu}g microcystin (MC)-LR/l drinking water. To verify the efficiency of two different water treatment systems with respect to reduction of cyanobacterial toxins, the concentrations of MC in water samples from surface waters and their associated water treatment plants in Switzerland and Germany were investigated. Toxin concentrations in samples from drinking water treatment plants ranged from below 1.0 {mu}g MC-LR equiv./l to more than 8.0 {mu}g/l in raw water and were distinctly below 1.0 {mu}g/l after treatment. In addition, data to the worldwide occurrence of cyanobacteria in raw and final water of water works and the corresponding guidelines for cyanobacterial toxins in drinking water worldwide are summarized.

  8. No Evidence of Complementary Water Use along a Plant Species Richness Gradient in Temperate Experimental Grasslands

    PubMed Central

    Bachmann, Dörte; Gockele, Annette; Ravenek, Janneke M.; Roscher, Christiane; Strecker, Tanja; Weigelt, Alexandra; Buchmann, Nina

    2015-01-01

    Niche complementarity in resource use has been proposed as a key mechanism to explain the positive effects of increasing plant species richness on ecosystem processes, in particular on primary productivity. Since hardly any information is available for niche complementarity in water use, we tested the effects of plant diversity on spatial and temporal complementarity in water uptake in experimental grasslands by using stable water isotopes. We hypothesized that water uptake from deeper soil depths increases in more diverse compared to low diverse plant species mixtures. We labeled soil water in 8 cm (with 18O) and 28 cm depth (with ²H) three times during the 2011 growing season in 40 temperate grassland communities of varying species richness (2, 4, 8 and 16 species) and functional group number and composition (legumes, grasses, tall herbs, small herbs). Stable isotope analyses of xylem and soil water allowed identifying the preferential depth of water uptake. Higher enrichment in 18O of xylem water than in ²H suggested that the main water uptake was in the upper soil layer. Furthermore, our results revealed no differences in root water uptake among communities with different species richness, different number of functional groups or with time. Thus, our results do not support the hypothesis of increased complementarity in water use in more diverse than in less diverse communities of temperate grassland species. PMID:25587998

  9. Storm water pollution prevention plan for the Oak Ridge Y-12 Plant

    SciTech Connect

    1995-09-01

    The Environmental Protection Agency (EPA) published the final storm water regulation on November 16, 1990. The storm water regulation is included in the National Pollutant Discharge Elimination System (NPDES) regulations. An NPDES permit was issued for the Y-12 Plant on April 28, 1995, and was effective on July 1, 1995. The permit requires that a Storm Water Pollution Prevention Plan (SWP3) be developed by December 28, 1995, and be fully implemented by July 1, 1996; this plan has been developed to fulfill that requirement. The outfalls and monitoring points described in this plan contain storm water discharges associated with industrial activities as defined in the NPDES regulations. For storm water discharges associated with industrial activity, including storm water discharges associated with construction activity, that are not specifically monitored or limited in this permit, Y-12 Plant personnel will meet conditions of the General Storm Water Rule 1200-4-10. This document presents the programs and physical controls that are in place to achieve the following objectives: ensure compliance with Section 1200-4-10-.04(5) of the TDEC Water Quality Control Regulations and Part 4 of the Y-12 Plant NPDES Permit (TN0002968); provide operating personnel with guidance relevant to storm water pollution prevention and control requirements for their facility and/or project; and prevent or reduce pollutant discharge to the environment, in accordance with the Clean Water Act (CWA) and the Tennessee Water Quality Control Act.

  10. No evidence of complementary water use along a plant species richness gradient in temperate experimental grasslands.

    PubMed

    Bachmann, Dörte; Gockele, Annette; Ravenek, Janneke M; Roscher, Christiane; Strecker, Tanja; Weigelt, Alexandra; Buchmann, Nina

    2015-01-01

    Niche complementarity in resource use has been proposed as a key mechanism to explain the positive effects of increasing plant species richness on ecosystem processes, in particular on primary productivity. Since hardly any information is available for niche complementarity in water use, we tested the effects of plant diversity on spatial and temporal complementarity in water uptake in experimental grasslands by using stable water isotopes. We hypothesized that water uptake from deeper soil depths increases in more diverse compared to low diverse plant species mixtures. We labeled soil water in 8 cm (with 18O) and 28 cm depth (with ²H) three times during the 2011 growing season in 40 temperate grassland communities of varying species richness (2, 4, 8 and 16 species) and functional group number and composition (legumes, grasses, tall herbs, small herbs). Stable isotope analyses of xylem and soil water allowed identifying the preferential depth of water uptake. Higher enrichment in 18O of xylem water than in ²H suggested that the main water uptake was in the upper soil layer. Furthermore, our results revealed no differences in root water uptake among communities with different species richness, different number of functional groups or with time. Thus, our results do not support the hypothesis of increased complementarity in water use in more diverse than in less diverse communities of temperate grassland species. PMID:25587998

  11. Research papers Does hyperaccumulated nickel affect leaf decomposition?

    E-print Network

    Boyd, Robert S.

    factors affect the decomposition rate of plant litter (Aerts 2006): 1) climate, 2) the nature of the soilResearch papers Does hyperaccumulated nickel affect leaf decomposition? A field test using Senecio Herbarium, School of Animal and Plant Sciences, University of the Witwatersrand, Private Bag 3, WITS 2050

  12. Reflectance of vegetation, soil, and water. [effects of measurable plant parameters on multispectral signal variations

    NASA Technical Reports Server (NTRS)

    Wiegand, C. L. (principal investigator)

    1974-01-01

    The author has identified the following significant results. Reflectance of crop residues, that are important in reducing wind and water erosion, was more often different from bare soil in band 4 than in bands 5, 6, or 7. The plant parameters leaf area index, plant population, plant cover, and plant height explained 95.9 percent of the variation in band 7 (reflective infrared) digital counts for cotton and 78.2 percent of the variation in digital counts for the combined crops sorghum and corn; hence, measurable plant parameters explain most of the signal variation recorded for corpland. Leaf area index and plant population are both highly correlated with crop yields; since plant population can be readily measured (or possibly inferred from seeding rates), it is useful measurement for calibrating ERTS-type MSS digital data in terms of yield.

  13. Processing Woman Creek runoff water by reverse osmosis. [From Rocky Flats oil shale plant

    SciTech Connect

    Plock, C.E.; Travis, T.N.; Dickman, A.A.; Marshall, S.C.; Esquibel, N.S.

    1981-12-14

    A mobil reverse osmosis pilot plant facility was used to evaluate cleanup of surface runoff water from the Rocky Flats Plant. The ability of the reverse osmosis process had been tested previously for removal of chemical of radionuclide contamination that could be picked up in water impounded from flood conditions at the Plant. The objective of the work was to evaluate the ability of pretreatment equipment to remove silt and colloids and to determine if membrane scaling would result. Membrane scaling did take place, and modifications will be needed to improve the pretreatment equipment.

  14. TECHNOLOGY TRANSFER HANDBOOK: MANAGEMENT OF WATER TREATMENT PLANT RESIDUALS

    EPA Science Inventory

    Potable water treatment processes produce safe drinking water and generate a wide variety of waste products known as residuals, including organic and inorganic compounds in liquid, solid, and gaseous forms. In the current regulatory climate, a complete management program for a w...

  15. Assessing Waste Water Treatment Plant Effluent for Thyroid Hormone Disruption

    EPA Science Inventory

    Much information has been coming to light on the estrogenic and androgenic activity of chemicals present in the waste water stream and in surface waters, but much less is known about the presence of chemicals with thyroid activity. To address this issue, we have utilized two assa...

  16. Innovative Fresh Water Production Process for Fossil Fuel Plants

    SciTech Connect

    James F. Klausner; Renwei Mei; Yi Li; Jessica Knight

    2006-09-29

    This project concerns a diffusion driven desalination (DDD) process where warm water is evaporated into a low humidity air stream, and the vapor is condensed out to produce distilled water. Although the process has a low fresh water to feed water conversion efficiency, it has been demonstrated that this process can potentially produce low cost distilled water when driven by low grade waste heat. This report summarizes the progress made in the development and analysis of a Diffusion Driven Desalination (DDD) system. Detailed heat and mass transfer analyses required to size and analyze the diffusion tower using a heated water input are described. The analyses agree quite well with the current data and the information available in the literature. The direct contact condenser has also been thoroughly analyzed and the system performance at optimal operating conditions has been considered using a heated water/ambient air input to the diffusion tower. The diffusion tower has also been analyzed using a heated air input. The DDD laboratory facility has successfully been modified to include an air heating section. Experiments have been conducted over a range of parameters for two different cases: heated air/heated water and heated air/ambient water. A theoretical heat and mass transfer model has been examined for both of these cases and agreement between the experimental and theoretical data is good. A parametric study reveals that for every liquid mass flux there is an air mass flux value where the diffusion tower energy consumption is minimal and an air mass flux where the fresh water production flux is maximized. A study was also performed to compare the DDD process with different inlet operating conditions as well as different packing. It is shown that the heated air/heated water case is more capable of greater fresh water production with the same energy consumption than the ambient air/heated water process at high liquid mass flux. It is also shown that there can be significant advantage when using the heated air/heated water process with a less dense less specific surface area packed bed. Use of one configuration over the other depends upon the environment and the desired operating conditions.

  17. Water Treatment Plant Operation. Volume I. A Field Study Training Program.

    ERIC Educational Resources Information Center

    California State Univ., Sacramento. School of Engineering.

    The purpose of this water treatment field study training program is to: (1) develop new qualified water treatment plant operators; (2) expand the abilities of existing operators, permitting better service both to employers and public; and (3) prepare operators for civil service and certification examinations (examinations administered by…

  18. 18 CFR 420.51 - Hydroelectric power plant water use charges.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... shall be charged one mill per kilowatt-hour of energy produced. (2) Owners of hydroelectric power plants... 18 Conservation of Power and Water Resources 2 2013-04-01 2012-04-01 true Hydroelectric power... BASIN COMMISSION ADMINISTRATIVE MANUAL BASIN REGULATIONS-WATER SUPPLY CHARGES Hydroelectric Power...

  19. 18 CFR 420.51 - Hydroelectric power plant water use charges.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... shall be charged one mill per kilowatt-hour of energy produced. (2) Owners of hydroelectric power plants... 18 Conservation of Power and Water Resources 2 2014-04-01 2014-04-01 false Hydroelectric power... BASIN COMMISSION ADMINISTRATIVE MANUAL BASIN REGULATIONS-WATER SUPPLY CHARGES Hydroelectric Power...

  20. 18 CFR 420.51 - Hydroelectric power plant water use charges.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... shall be charged one mill per kilowatt-hour of energy produced. (2) Owners of hydroelectric power plants... 18 Conservation of Power and Water Resources 2 2012-04-01 2012-04-01 false Hydroelectric power... BASIN COMMISSION ADMINISTRATIVE MANUAL BASIN REGULATIONS-WATER SUPPLY CHARGES Hydroelectric Power...

  1. 18 CFR 420.51 - Hydroelectric power plant water use charges.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... shall be charged one mill per kilowatt-hour of energy produced. (2) Owners of hydroelectric power plants... 18 Conservation of Power and Water Resources 2 2011-04-01 2011-04-01 false Hydroelectric power... BASIN COMMISSION ADMINISTRATIVE MANUAL BASIN REGULATIONS-WATER SUPPLY CHARGES Hydroelectric Power...

  2. SEATTLE DISTRIBUTION SYSTEM CORROSION CONTROL STUDY. VOLUME 2. TOLT RIVER WATER PILOT PLANT STUDY

    EPA Science Inventory

    For 6 months, the Seattle Water Department conducted a corrosion treatment pilot plant study, obtaining data on the treatment of Tolt River water with lime/sodium carbonate, lime/sodium bicarbonate, and lime/bicarbonate/silicate. Continuous-flow pipe coupon tests were conducted t...

  3. Effect of tephra deposition and planting treatment on soil oxygen levels and water relations of newly planted seedlings

    SciTech Connect

    Schulte, P.J.; Teskey, R.O.; Hinckley, T.M.; Stevens, R.G.; Leslie, D.A.

    1985-03-01

    Seedlings planted in late June 1980 near Mount St. Helens, following the May 18 and 25 eruptions, continuously lost vigor. Studies on seedlings planted in April 1981 were conducted in 1981-82 on sites covered with 10 to 35 cm of tephra. Soil oxygen levels measured at 10 and 20 cm depths below the tephra surface decreased with increasing tephra thickness, tephra moisture, and sampling depth in the tephra. In addition, the method of planting appeared to affect soil oxygen levels. Holes dug into the tephra for planting seedlings in the mineral soil allowed water and fine particles to collect and possibly interfere with soil gas exchange. However, oxygen levels were never less than 11 percent and generally about 14 percent. Levels were never low enough to result in a root oxygen stress. Measurement of the oxygen diffusion coefficient in tephra and the physical characterization of the tephra failed to demonstrate the existence of any unusual features that might lead to the development of an oxygen stress. A controlled environment study was conducted to observe seedlings under conditions of tephra coverage of the soil. The water relations of these seedlings indicated no response due to a root oxygen stress. The lack of oxygen stress in the field corresponded with the maintenance of high vigor in seedlings planted in 1981.

  4. Thermoeconomic optimization of OC-OTEC electricity and water production plants

    SciTech Connect

    Block, D.L.; Valenzuela, J.A.

    1985-05-01

    The study on the thermoeconomic evaluation of open-cycle ocean thermal energy conversion (OC-OTEC) objectives were to assess the economic and technical viability of OC-OTEC for the production of electricity and fresh water based on the current state-of-the-art; develop conceptual designs of optimized OC-OTEC plants that produce electricity and fresh water for plant sizes that are economically attractive; and identify the research issues that must be resolved before a commercial plant can be built. Oceanographic data for six potential sites were evaluated and ''generic'' site characteristics were developed. Current and projected prices and requirements for electricity and water at potential sites were obtained. The state-of-the-art of components comprising the OC-OTEC plant was reviewed. The highest performing, least costly, and least technically uncertain design for each component was selected. Component cost and performance models were then developed and integrated into thermoeconomic system models for single- and double-stage OC-OTEC plants that produced electricity and fresh water. A computerized optimization procedure was developed to obtain optimal plant configurations for the production of electricity and fresh water. Small-scale OC-OTEC appears economically and technologically feasible for many potential sites. OC-OTEC may represent a technology with tremendous near-term potential. It is recommended that it be aggressively pursued.

  5. Management intensity alters decomposition via biological pathways

    USGS Publications Warehouse

    Wickings, Kyle; Grandy, A. Stuart; Reed, Sasha; Cleveland, Cory

    2011-01-01

    Current conceptual models predict that changes in plant litter chemistry during decomposition are primarily regulated by both initial litter chemistry and the stage-or extent-of mass loss. Far less is known about how variations in decomposer community structure (e.g., resulting from different ecosystem management types) could influence litter chemistry during decomposition. Given the recent agricultural intensification occurring globally and the importance of litter chemistry in regulating soil organic matter storage, our objectives were to determine the potential effects of agricultural management on plant litter chemistry and decomposition rates, and to investigate possible links between ecosystem management, litter chemistry and decomposition, and decomposer community composition and activity. We measured decomposition rates, changes in litter chemistry, extracellular enzyme activity, microarthropod communities, and bacterial versus fungal relative abundance in replicated conventional-till, no-till, and old field agricultural sites for both corn and grass litter. After one growing season, litter decomposition under conventional-till was 20% greater than in old field communities. However, decomposition rates in no-till were not significantly different from those in old field or conventional-till sites. After decomposition, grass residue in both conventional- and no-till systems was enriched in total polysaccharides relative to initial litter, while grass litter decomposed in old fields was enriched in nitrogen-bearing compounds and lipids. These differences corresponded with differences in decomposer communities, which also exhibited strong responses to both litter and management type. Overall, our results indicate that agricultural intensification can increase litter decomposition rates, alter decomposer communities, and influence litter chemistry in ways that could have important and long-term effects on soil organic matter dynamics. We suggest that future efforts to more accurately predict soil carbon dynamics under different management regimes may need to explicitly consider how changes in litter chemistry during decomposition are influenced by the specific metabolic capabilities of the extant decomposer communities.

  6. Modeling climate change impacts on maize growth with the focus on plant internal water transport

    NASA Astrophysics Data System (ADS)

    Heinlein, Florian; Biernath, Christian; Klein, Christian; Thieme, Christoph; Priesack, Eckart

    2015-04-01

    Based on climate change experiments in chambers and on field measurements, the scientific community expects regional and global changes of crop biomass production and yields. In central Europe one major aspect of climate change is the shift of precipitation towards winter months and the increase of extreme events, e.g. heat stress and heavy precipitation, during the main growing season in summer. To understand water uptake, water use, and transpiration rates by plants numerous crop models were developed. We tested the ability of two existing canopy models (CERES-Maize and SPASS) embedded in the model environment Expert-N5.0 to simulate the water balance, water use efficiency and crop growth. Additionally, sap flow was measured using heat-ratio measurement devices at the stem base of individual plants. The models were tested against data on soil water contents, as well as on evaporation and transpiration rates of Maize plants, which were grown on lysimeters at Helmholtz Zentrum München and in the field at the research station Scheyern, Germany, in summer 2013 and 2014. We present the simulation results and discuss observed shortcomings of the models. CERES-Maize and SPASS could simulate the measured dynamics of xylem sap flow. However, these models oversimplify plant water transport, and thus, cannot explain the underlying mechanisms. Therefore, to overcome these shortcomings, we additionally propose a new model, which is based on two coupled 1-D Richards equations, describing explicitly the plant and soil water transport. This model, which has previously successfully been applied to simulate water flux of 94 individual beech trees of an old-grown forest, will lead to a more mechanistic representation of the soil-plant-water-flow-continuum. This xylem water flux model was now implemented into the crop model SPASS and adjusted to simulate water flux of single maize plants. The modified version is presented and explained. Basic model input requirements are the plant above- and below-ground architectures. Shoot architectures were derived from terrestrial laser scanning. Root architectures of Maize plants were generated using a simple L-system. Preliminary results will be presented together with simulation results by CERES-Maize and SPASS.

  7. Tea plant uptake and translocation of polycyclic aromatic hydrocarbons from water and around air.

    PubMed

    Lin, Daohui; Zhu, Lizhong; He, Wei; Tu, Youying

    2006-05-17

    This study, which aimed to investigate the capacity of tea plant uptake and translocation of polycyclic aromatic hydrocarbons (PAHs), was divided into two sections. One was to study tea plant root uptake of PAHs from water and translocation to leaves. The other was to research tea plant leaf uptake of PAHs from air. It was observed that tea plant roots and leaves could strongly accumulate PAHs from around the environment. The capacity of tea plant uptake and translocation of PAHs were found to be closely relative to the physical-chemical properties of PAHs. With the increase of IgK(ow) (octanol-water partition coefficient) of the PAHs, both root concentration factors and leaf concentration factors increased exponentially, while translocation factors from roots to leaves decreased exponentially. PMID:19127741

  8. Simultaneous production of desalinated water and power using a hybrid-cycle OTEC plant

    SciTech Connect

    Panchal, C.B.; Bell, K.J.

    1987-05-01

    A systems study for simultaneous production of desalinated water and electric power using the hybrid-cycle OTEC system was carried out. The hybrid cycle is a combination of open and closed-cycle OTEC systems. A 10 MWe shore-based hybrid-cycle OTEC plant is discussed and corresponding operating parameters are presented. Design and plant operating criteria for adjusting the ratio of water production to power generation are described and their effects on the total system were evaluated. The systems study showed technical advantages of the hybrid-cycle power system as compared to other leading OTEC systems for simultaneous production of desalinated water and electric power generation.

  9. Plant Pathogen-Induced Water-Soaking Promotes Salmonella enterica Growth on Tomato Leaves.

    PubMed

    Potnis, Neha; Colee, James; Jones, Jeffrey B; Barak, Jeri D

    2015-12-01

    Plant pathogen infection is a critical factor for the persistence of Salmonella enterica on plants. We investigated the mechanisms responsible for the persistence of S. enterica on diseased tomato plants by using four diverse bacterial spot Xanthomonas species that differ in disease severities. Xanthomonas euvesicatoria and X. gardneri infection fostered S. enterica growth, while X. perforans infection did not induce growth but supported the persistence of S. enterica. X. vesicatoria-infected leaves harbored S. enterica populations similar to those on healthy leaves. Growth of S. enterica was associated with extensive water-soaking and necrosis in X. euvesicatoria- and X. gardneri-infected plants. The contribution of water-soaking to the growth of S. enterica was corroborated by an increased growth of populations on water-saturated leaves in the absence of a plant pathogen. S. enterica aggregates were observed with bacterial spot lesions caused by either X. euvesicatoria or X. vesicatoria; however, more S. enterica aggregates formed on X. euvesicatoria-infected leaves as a result of larger lesion sizes per leaf area and extensive water-soaking. Sparsely distributed lesions caused by X. vesicatoria infection do not support the overall growth of S. enterica or aggregates in areas without lesions or water-soaking; S. enterica was observed as single cells and not aggregates. Thus, pathogen-induced water-soaking and necrosis allow S. enterica to replicate and proliferate on tomato leaves. The finding that the pathogen-induced virulence phenotype affects the fate of S. enterica populations in diseased plants suggests that targeting of plant pathogen disease is important in controlling S. enterica populations on plants. PMID:26386057

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

    SciTech Connect

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

    2005-01-15

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

  11. Characterization of plutonium in ground water near the idaho chemical processing plant

    USGS Publications Warehouse

    Cleveland, J.M.

    1982-01-01

    Plutonium is present in very low concentrations in ground water near the disposal well at the Idaho Chemical Processing Plant but was not detected in waters at greater distances. Because of the absence of strong complexing agents, the plutonium is present as an uncomplexed (perhaps hydrolyzed) tetravalent species, which is readily precipitated or sorbed by basalt or sediments along the ground-water flow path.

  12. Modelling the influence of plants on the spatial heterogeneity of soil water

    NASA Astrophysics Data System (ADS)

    Malchow, Melanie; van Schaik, Loes; Tietjen, Britta

    2015-04-01

    Plants are sessile organisms and as such depend on sufficient local water supply. At the same time, plants themselves directly influence the spatial water distribution in the soil. Thus, plants partly regulate their own water supply. Current ecohydrological models apply simplified approaches to assess infiltration and the spatial distribution of water. They often neglect the influence of the vegetation the spatial heterogeneity in soil water. For example, the shape of the leafage and the rooting system strongly impact the amount of water that reaches the soil and how it is spatially distributed. If rainfall hits the leafage only a fraction of the water falls trough directly. The remaining fraction is intercepted and firstly accumulates on the leaves. This water either runs down the stem (stem flow) or evaporates directly. As a result, more water is received in the local environment of the stem than under the remaining canopy. The rooting system additionally influences the amount of infiltrated water and its distribution in the soil: Roots lead to preferential flow paths and form small caverns that increase the water storage capacity. In our work we developed a simulation model (using Netlogo) to track the path of rainfall from its first contact with the leafage to its storage in the soil. Our model structure supports simulations for different morphological plant types that allow us to evaluate the effect of branch structure, leaf density and the rooting system on water fluxes and thus local availability. The parameterization of morphological traits is based on 2-D profiles derived by simple image processing of pictures. This provides a highly flexible framework to evaluate different scenarios, which we aim to couple with a dynamic vegetation model in the future.

  13. Design solutions for water treatment plants constructed on the basis of membrane technologies

    NASA Astrophysics Data System (ADS)

    Panteleev, A. A.; Ryabchikov, B. E.; Zhadan, A. V.; Khoruzhii, O. V.

    2012-07-01

    Two process circuits for demineralizing makeup water for power units at thermal power stations are considered. One of them is constructed on the basis of a combined plant comprising reverse-osmosis and ion-exchange apparatuses and the other comprises reverse-osmosis and electric deionization apparatuses. The considered circuits are analyzed by way of comparing them with the traditional chemical water demineralization system. Advantages and drawbacks of the new technologies for treating natural water are pointed out.

  14. Predictive Modeling of Large-Scale Commercial Water Desalination Plants: Data-Based Neural Network and Model-Based Process

    E-print Network

    Liu, Y. A.

    Predictive Modeling of Large-Scale Commercial Water Desalination Plants: Data-Based Neural Network for developing predictive models for large-scale commercial water desalination plants by (1) a data (MSF) and reverse osmosis (RO) desalination plants in the world. Our resulting neural network

  15. Summary Plant tissues shrink and swell in response to changes in water pressure. These strains can be easily mea-

    E-print Network

    Podgornik, Rudolf

    pressure is transmitted to cell walls and causes shrinkage of plant tissues, particularly in the case. Water is also closely bonded to plant cell walls, so that the water tension is, at least partly). The transmission of pressure from a fluid through solid cell walls also causes shrinkage and swelling of plant

  16. Interactive effects of elevated CO{sub 2}, drought and high temperature on plant water use efficiency

    SciTech Connect

    Theodore C. Hsiao

    1998-08-01

    Water use efficiency (WUE) by plants is a key determinant of productivity and survival of plants under water limiting or drought conditions. The aim of this project was to develop a mechanistic basis for predicting WUE without the prohibitive task of studying every plant species under a range of environmental conditions.

  17. Estimating spatially distributed soil water content at small watershed scales based on decomposition of temporal anomaly and time stability analysis

    NASA Astrophysics Data System (ADS)

    Hu, W.; Si, B. C.

    2015-07-01

    Soil water content (SWC) at watershed scales is crucial to rainfall-runoff response. A model was used to decompose spatiotemporal SWC into time-stable pattern (i.e., temporal mean), space-invariant temporal anomaly, and space-variant temporal anomaly. This model was compared with a previous model that decomposes spatiotemporal SWC into spatial mean and spatial anomaly. The space-variant temporal anomaly or spatial anomaly was further decomposed using the empirical orthogonal function for estimating spatially distributed SWC. These two models are termed temporal anomaly (TA) model and spatial anomaly (SA) model, respectively. We aimed to test the hypothesis that underlying (i.e., time-invariant) spatial patterns exist in the space-variant temporal anomaly at the small watershed scale, and to examine the advantages of the TA model over the SA model in terms of estimation of spatially distributed SWC. For this purpose, a SWC dataset of near surface (0-0.2 m) and root zone (0-1.0 m) from a small watershed scale in the Canadian prairies was analyzed. Results showed that underlying spatial patterns exist in the space-variant temporal anomaly because of the permanent controls of "static" factors such as depth to the CaCO3 layer and organic carbon content. Combined with time stability analysis, the TA model improved estimation of spatially distributed SWC over the SA model because the latter failed to capture the space-variant temporal anomaly which accounted for non-negligible amounts of spatial variance in SWC. The outperformance was greater when SWC deviated from intermediate conditions, especially for dry conditions. Therefore, the TA model has potential to construct a spatially distributed SWC at watershed scales from remote sensed SWC.

  18. Making the most of increased water flow: Expanding the Devil Canyon hydro plant

    SciTech Connect

    DePuy, B.E.; Butler, R.C. )

    1992-04-01

    Amidst the longest California drought on record, work is proceeding to bring additional water to the southern part of the state. With extra water comes an opportunity for increasing hydro - one project is underway to add 160 MW of power to an existing 120-MW plant. The California State Department of Water Resources (DWR) completed the initial phase of its State Water Project 20 years ago. However, the state designed into the system provisions for future enlargement to meet anticipated increased water demands. Growth in southern California during the last ten years has been unprecedented. To meet demands for additional water supplies, in 1986 DWR and several of its water contractors signed water contract agreements to enlarge part of the California Aqueduct. This enlargement meant that increased flows would be available to the 120-MW Devil Canyon hydroelectric facility, the southernmost plant along the aqueduct. As a result, DWR is expanding Devil Canyon. The project expansion includes: enlargement of the powerhouse to allow room for two new units of 80 MW each; addition of a second penstock; and the addition of a second, larger afterbay. More than 15 primary contractors have worked on or are working on project contracts totaling more than $82.5 million. When water begins passing through the completed power plant in April 1992, Devil Canyon will be capable of producing an additional 160 MW of electricity.

  19. Effect of top soil wettability on water evaporation and plant growth.

    PubMed

    Gupta, Bharat; Shah, D O; Mishra, Brijesh; Joshi, P A; Gandhi, Vimal G; Fougat, R S

    2015-07-01

    In general, agricultural soil surfaces being hydrophilic in nature get easily wetted by water. The water beneath the soil moves through capillary effect and comes to the surface of the soil and thereafter evaporates into the surrounding air due to atmospheric conditions such as sunlight, wind current, temperature and relative humidity. To lower the water loss from soil, an experiment was designed in which a layer of hydrophobic soil was laid on the surface of ordinary hydrophilic soil. This technique strikingly decreased loss of water from the soil. The results indicated that the evaporation rate significantly decreased and 90% of water was retained in the soil in 83 h by the hydrophobic layer of 2 cm thickness. A theoretical calculation based on diffusion of water vapour (gas phase) through hydrophobic capillaries provide a meaningful explanation of experimental results. A greater retention of water in the soil by this approach can promote the growth of plants, which was confirmed by growing chick pea (Cicer arietinum) plants and it was found that the length of roots, height of shoot, number of branches, number of leaves, number of secondary roots, biomass etc. were significantly increased upon covering the surface with hydrophobic soil in comparison to uncovered ordinary hydrophilic soil of identical depth. Such approach can also decrease the water consumption by the plants particularly grown indoors in residential premises, green houses and poly-houses etc. and also can be very useful to prevent water loss and enhance growth of vegetation in semi-arid regions. PMID:25801650

  20. Water Status of Arctic Tundra Plants During the Winter-Spring Transition

    NASA Astrophysics Data System (ADS)

    Oberbauer, S. F.; Olivas, P. C.; Moser, J.; Starr, G.; Mortazavi, B.

    2012-12-01

    The arctic winter-spring transition when full snow cover rapidly changes to snow-free conditions potentially represents a time of physiological stress for tundra plants. Plants that have been subjected to freezing temperatures for several months over winter are suddenly exposed to high radiation loads from clear skies and reflection from unmelted snow. Water uptake at this time may be limited by low stem temperatures and cold or even frozen soils. Because of these potential stresses it may be advantageous for plants to delay photosynthetic activity and water loss until soils are warmer. However, given the short length of the growing season, the optimal strategy for plants may be to maximize carbon uptake and begin photosynthesis and growth as soon as possible after snowmelt. Some tundra evergreens even photosynthesize under snow cover. To test the hypothesis that plant water stress increases immediately following loss of snow cover, we investigated xylem and leaf osmotic potentials of evergreen tundra species before and immediately after snowmelt. We also compared these measurements with summer and winter measurements. Our study was conducted in moist acidic tundra near Toolik Field Station in the northern foothills of the Brooks Range, Alaska. Xylem water potentials were measured by Scholander pressure chamber and osmotic potentials by psychrometry of cell sap expressed from frozen (-80 °C) leaf tissue. Xylem water potentials under snow were generally higher than those of plants recently released from snow. Osmotic potentials measured before and after snowmelt did not show evidence of strong changes. Some species, such as Ledum palustre, maintained high water potentials both under snow and shortly after snow melt. With only a few exceptions, water potentials just after melt out were generally higher than those after soils had warmed and plants had greened up. Low water potentials (< -3 MPa) were most commonly found in Cassiope tetragona, a snowbed-associated species that showed noticeable shoot mortality in two of the three sample years. Winter measurements revealed low water potentials in some samples of Cassiope tetragona, Empetrum nigrum, and Vaccinium vitis-ideae. However, considerable variation in water potentials was found under both snow-covered and snow-free conditions and among the three sample years, likely as a result of differences in winter temperature regimes and snow cover properties. Changes in winter temperature and snow cover regimes will likely have important consequences for plant water status and shoot mortality during winter and the spring thaw.

  1. Hydrogen iodide decomposition

    DOEpatents

    O'Keefe, Dennis R. (San Diego, CA); Norman, John H. (San Diego, CA)

    1983-01-01

    Liquid hydrogen iodide is decomposed to form hydrogen and iodine in the presence of water using a soluble catalyst. Decomposition is carried out at a temperature between about 350.degree. K. and about 525.degree. K. and at a corresponding pressure between about 25 and about 300 atmospheres in the presence of an aqueous solution which acts as a carrier for the homogeneous catalyst. Various halides of the platinum group metals, particularly Pd, Rh and Pt, are used, particularly the chlorides and iodides which exhibit good solubility. After separation of the H.sub.2, the stream from the decomposer is countercurrently extracted with nearly dry HI to remove I.sub.2. The wet phase contains most of the catalyst and is recycled directly to the decomposition step. The catalyst in the remaining almost dry HI-I.sub.2 phase is then extracted into a wet phase which is also recycled. The catalyst-free HI-I.sub.2 phase is finally distilled to separate the HI and I.sub.2. The HI is recycled to the reactor; the I.sub.2 is returned to a reactor operating in accordance with the Bunsen equation to create more HI.

  2. Computing Cylindrical Algebraic Decomposition via Triangular Decomposition

    E-print Network

    Moreno Maza, Marc

    Computing Cylindrical Algebraic Decomposition via Triangular Decomposition Changbo Chen1 , Marc University, Beijing, China 3 East China Normal University, Shanghai, China Overview Cylindrical algebraic Cylindrical:we transform the initial partition and obtain an- other partition of C n into disjoint

  3. Worldwide assessment of steam-generator problems in pressurized-water-reactor nuclear power plants

    SciTech Connect

    Woo, H.H.; Lu, S.C.

    1981-09-15

    Objective is to assess the reliability of steam generators of pressurized water reactor (PWR) power plants in the United States and abroad. The assessment is based on operation experience of both domestic and foreign PWR plants. The approach taken is to collect and review papers and reports available from the literature as well as information obtained by contacting research institutes both here and abroad. This report presents the results of the assessment. It contains a general background of PWR plant operations, plant types, and materials used in PWR plants. A review of the worldwide distribution of PWR plants is also given. The report describes in detail the degradation problems discovered in PWR steam generators: their causes, their impacts on the performance of steam generators, and the actions to mitigate and avoid them. One chapter is devoted to operating experience of PWR steam generators in foreign countries. Another discusses the improvements in future steam generator design.

  4. A Model of Water Resources & Thermoelectric Plant Productivity Considering Changing Climates & Environmental Policy

    NASA Astrophysics Data System (ADS)

    Miara, A.; Vorosmarty, C. J.; Stewart, R. J.; Wollheim, W. M.; Rosenzweig, B.

    2012-12-01

    In the Northeast US, approximately 80% of the available capacity of thermoelectric plants is dependent on the constant availability of water for cooling. Cooling is a necessary process whereby the waste thermal load of a power plant is released and the working fluid (typically steam) condensed to allow the continuation of the thermodynamic cycle and the extraction of electrical power through the action of turbines. Power plants rely on a minimum flow at a certain temperature, determined by the individual plant engineering design, to be sufficiently low for their cooling. Any change in quantity or temperature of water could reduce thermal efficiencies. As a result of the cooling process, power plants emit thermal pollution into receiving waters, which is harmful to freshwater aquatic ecosystems including its resident life forms and their biodiversity. The Clean Water Act of 1972 (CWA) was established to limit thermal pollution, particularly when rivers reach high temperatures. When river temperatures approach the threshold limit, the power plants that use freshwater for cooling are forced to reduce their thermal load and thus their output to comply with the regulations. Here we describe a model that quantifies, in a regional context, thermal pollution and estimates efficiency losses as a result of fluctuating river temperatures and flow. It does this using available data, standard engineering equations describing the heat cycle of power plants and their water use, and assumptions about the operations of the plant. In this presentation, we demonstrate the model by analyzing contrasting climates with and without the CWA, focusing on the productivity of 366 thermoelectric plants that rely on water for cooling in the Northeast between the years 2000-2010. When the CWA was imposed on all simulated power plants, the model shows that during the average winter and summer, 94% and 71% of required generation was met from the power plants, respectively. This suggests that if all power plants were to comply with the CWA and if temperatures do increase in the future as is expected under greenhouse warming, electric power generation in the Northeast may become limited, particularly in the summer. To avoid a potential energy gap, back-up generators and other electric infrastructure, such as hydropower, may have to come online in order to meet the total electric demand. Furthermore, it is clear that the methodology and steps taken in the model are required to more accurately understand, estimate and evaluate the relationship between energy production, environmental and energy policy and biodiversity under forecasted and historic climate conditions. Our ongoing work uses this model to explore various future scenarios of policy, climate and natural resource management in the Northeastern US for the period 2010-2100.

  5. Geratology and decomposition of Spartina versicolor in a brackish Mediterranean marsh

    NASA Astrophysics Data System (ADS)

    Menéndez, Margarita; Sanmartí, Neus

    2007-08-01

    Most studies on plant decomposition in salt marshes have been carried out in Spartina-dominated marshes in North America. In contrast, few have focused on marshes in Mediterranean systems. Moreover, research into litter decay in estuarine systems has been conducted with plant material collected before natural senescence and death. Here we followed the growth, senescence, leaf fall, and nutrient dynamics of Spartina versicolor to examine litter decay in a Mediterranean coastal system. We studied the dynamics of fungi, meiofauna and algae associated with detached S. versicolor litter, and the effect of the microenvironment (above and underneath wracks of dead Spartina) on decomposition. The exponential decay coefficient rate ( k, day -1) was higher for leaves attached to standing plants (0.0019) than after leaf abscission (0.0002-0.001). The decomposition rate of detached leaves was highly variable and depended on the position of the litter. The large differences in decomposition rates between the two experimental conditions indicate that the microenvironment affected the associated litter community during the initial phase of decay. Water availability and high temperatures over the sediment surface increased the density of meiofauna and epiphyton and decreased fungal biomass during the first 20 days of the experiment. Fungal biomass was at the lower end of reported values, probably as a result of the drier conditions and high salinity in the Mediterranean marsh. Spartina versicolor detritus acted as a nutrient sink by immobilizing large amounts of N and P for at least one year.

  6. Plant Water Use and Environmental Stress on Two Opposite Slopes: from Water and Carbon Stable Isotopic Perspective

    NASA Astrophysics Data System (ADS)

    Guan, H.; Xu, X.; Skrzypek, G.; Simmons, C. T.

    2014-12-01

    Climate-soil-vegetation dynamics are among key research focuses in the emerging ecohydrology discipline. Topographic relieves on landscapes provide various hydroclimatic conditions to examine vegetation functions and its responses to climate variation and changes in a short distance. In this study, we investigate ecohydrologic processes on two slopes of contrasting orientation and soil conditions in a native vegetation catchment with mean annual precipitation of 716 mm in South Australia, using water and carbon stable isotopes. Throughfall, soil water, twig water, and groundwater stable isotopes were measured and integrated into an isotope incorporated soil-plant-atmosphere model to examine different plant water use patterns on two slopes with different environmental conditions. The focuses are on how ecosystems on the two slopes receive, store, and use soil moisture in different manners. On these two slopes, trees are under different water stresses. Both leaf and soil 13C/12C ratio were measured for the two slopes to examine if ?13C can be used as an water stress indicator in this small catchment, and if the potential difference in ?13C can be observed in the soil organic matter. We monitored one-year leaf ?13C of two tree species, Eucalyptus leucoxylon and Acacia pycnantha. Our results indicate that leaf ?13C reflects different water stress conditions between slopes, seasons, and different locations on the slopes.

  7. Determination of the ?2H and ?18O of soil water and water in plant matter; RSIL lab code 1700

    USGS Publications Warehouse

    Revesz, Kinga M.; Buck, Bryan; Coplen, Tyler B.

    2012-01-01

    The purpose of the Reston Stable Isotope Laboratory lab code 1700 is to determine the ?2H/1H), abbreviated as ?2H, and the ?18O/16O), abbreviated as ?18O, of soil water and water in plant matter. This method is based on the observation that water and toluene form an azeotropic mixture at 84.1 °C. This temperature is substantially lower than the boiling points of water (100 °C) and toluene (110 °C), but water and toluene are immiscible at ambient temperature. The water content of a soil or plant is determined by weighing, drying, and reweighing a small amount of sample. Sufficient sample to collect 3 to 5 milliliters of water after distillation is loaded into a distillation flask. Sufficient toluene is added so that the sample is immersed throughout the entire distillation to minimize evaporation of water, which would affect the ?2H and ?18O values. The mixture of sample and toluene is heated in a flask to its boiling point (84.1 °C) so that water from the sample and toluene can distill together into a specially designed collection funnel. The temperature of 84.1 °C is maintained until the water has been quantitatively transferred to the collection funnel, at which time the temperature is raised to the boiling point of the remaining component (toluene, 110 °C). The collection funnel is maintained at ambient temperature so that the sample water and toluene can be separated physically. After separation, the sample water is purified by addition of paraffin wax to the container with the sample water, capping the container, and heating to approximately 60 °C to melt the wax. Trace amounts of toluene will dissolve in the wax, purifying the sample water for isotopic analysis. The isotopic composition of the purified water is then determined by equilibration with gaseous hydrogen or carbon dioxide, followed by dual-inlet isotope-ratio mass spectrometry. Because laser-absorption spectrometry is sensitive to organic compounds, such as trace toluene remaining in water samples, water samples should be analyzed for isotopic composition only by mass spectrometry and not by laser-absorption spectrometry.

  8. Air radon concentration decrease in a waste water treatment plant.

    PubMed

    Juste, B; Ortiz, J; Verdú, G; Martorell, S

    2015-06-01

    (222)Rn is a naturally occurring gas created from the decay of (226)Ra. The long-term health risk of breathing radon is lung cancer. One particular place where indoor radon concentrations can exceed national guidelines is in wastewater treatment plants (WWTPs) where treatment processes may contribute to ambient airborne concentrations. The aim of this paper was to study the radon concentration decrease after the application of corrective measures in a Spanish WWTP. According to first measures, air radon concentration exceeded International Commission Radiologica1 Protection (ICRP) normative (recommends intervention between 400 and 1000 Bq m(-3)). Therefore, the WWTP improved mechanical forced ventilation to lower occupational exposure. This measure allowed to increase the administrative controls, since the limitation of workers access to the plant changed from 2 h d(-1) (considering a maximum permissible dose of 20 mSv y(-1) averaged over 5 y) to 7 h d(-1). PMID:25971342

  9. Changes in plant water use efficiency over the recent past reconstructed using palaeo plant records from the boreal forest

    NASA Astrophysics Data System (ADS)

    Gagen, M.; Finsinger, W.; McCarroll, D.; Wagner, F.

    2009-04-01

    The Boreal forests contains 33% of the earth's forest cover and are located at the latitude where most of the estimated global warming is predicted to occur. Warming as a consequence of rising carbon dioxide will affect evapotranspiration within the biome, with significant consequences given that water vapour is an important greenhouse gas. However, there is also a physiological forcing associated with the effects of rising carbon dioxide on plants. Higher atmospheric carbon dioxide will reduce evapotraspiration because tree stomata tend to close under elevated carbon dioxide. The warming associated with reduced evapotranspiration is known as carbon dioxide physiological forcing and it is not well constrained. Here we suggest that future predictions of evapotranspiration flux within the Boreal forest zone might be more accurately gauged by taking account of palaeo evidence of changing plant water use efficiency and stomatal density in the two most important Boreal plant species: Pinus sylvestris and Betula nana. Stable carbon isotope ratios in tree ring cellulose and stomatal density measurements, from preserved leaves falling on the forest floor, hold a record of the plant physiological changes associated with adjustment to rising carbon dioxide. We present evidence that, rather than plants simply closing their stomatal apertures under recent elevated carbon dioxide, over the last 150 years reduced evapotranspiration in the northern Boreal forest has been associated with a powerful plastic response including reductions in stomatal conductance via changes in stomatal density and pore length. Furthermore we present evidence that trees may be reaching the limits of their ability to respond plastically to rising carbon dioxide by increasing their water use efficiency.

  10. Occurrence of selected pharmaceuticals at drinking water purification plants in Japan and implications for human health.

    PubMed

    Simazaki, Dai; Kubota, Reiji; Suzuki, Toshinari; Akiba, Michihiro; Nishimura, Tetsuji; Kunikane, Shoichi

    2015-06-01

    The present study was performed to determine the occurrence of 64 pharmaceuticals and metabolites in source water and finished water at 6 drinking water purification plants and 2 industrial water purification plants across Japan. The analytical methods employed were sample concentration using solid-phase extraction cartridges and instrumental analysis by liquid chromatography with tandem mass spectrometry (LC-MS/MS), liquid chromatography with mass spectrometry (LC/MS), or trimethylsilyl derivatization followed by gas chromatography with mass spectrometry (GC/MS). Thirty-seven of the 64 target substances were detected in the source water samples. The maximum concentrations in the source water were mostly below 50 ng/L except for 13 substances. In particular, residual concentrations of iopamidol (contrast agent) exceeded 1000 ng/L at most facilities. Most of the residual pharmaceuticals and metabolites in the source water samples were removed in the course of conventional and/or advanced drinking water treatments, except for 7 pharmaceuticals and 1 metabolite, i.e., amantadine, carbamazepine, diclofenac, epinastine, fenofibrate, ibuprofen, iopamidol, and oseltamivir acid. The removal ratios of the advanced water treatment processes including ozonation and granular activated carbon filtration were typically much higher than those of the conventional treatment processes. The margins of exposure estimated by the ratio of daily minimum therapeutic dose to daily intake via drinking water were substantial, and therefore the pharmacological and physiological impacts of ingesting those residual substances via drinking water would be negligible. PMID:25835589

  11. WATER RECYCLE/REUSE ALTERNATIVES IN COAL-FIRED STEAM-ELECTRIC POWER PLANTS: VOLUME I. PLANT STUDIES AND GENERAL IMPLEMENTATION PLANS

    EPA Science Inventory

    The report gives results of an investigation of water recycle/treatment/reuse alternatives in coal-fired power plants. Five power plants from representative U.S. regions were studied. The major water systems encountered were cooling, ash sluicing, and SO2/particulate scrubbers. R...

  12. The synthesis, activity, stability and the charge transfer identification of Ag:AgBr/?-Al2O3 photocatalyst for organic pollutant decomposition in water

    NASA Astrophysics Data System (ADS)

    Huang, Shan; Si, Zhichun; Weng, Duan

    2015-12-01

    Highly stable Ag:AgBr/?-Al2O3 photo-catalyst was obtained by dispersing AgBr sol on hollow ?-Al2O3 microsphere. Metallic Ag nanoparticles were in situ generated on AgBr crystals by a photo-reduction method. The activity of catalyst was characterized by MO and phenol decomposition. The light irradiation response, the life times of the photo-induced charges, and the charge separation and transition were determined by the UV-vis diffuse reflection spectra, open circuit voltage decay spectra and transient photocurrent responses. The as-prepared Ag:AgBr/?-Al2O3 catalyst can response to visible light irradiation. Charge separation was clarified to correlate with electrons transferring from Ag to AgBr surface and the consequent reaction with ads-O2 to generate rad O2- species. It was found that the rad O2- rather than rad OH played a dominant role in the photocatalytic oxidation of MO and phenol in water. However, the electrons trended to transfer from AgBr to Ag intrinsically without light irradiation. Therefore, the electron transfer between Ag and AgBr reaching the dynamic equilibrium was the key factor for obtaining a high stable Ag/AgBr catalyst which can be obtained by optimizing the Ag:AgBr ratio. Loading amount of Ag:AgBr on ?-Al2O3 was optimized to 30 wt.% and the metallic Ag content was stabilized at 9 wt.% of Ag:AgBr catalyst.

  13. 76 FR 66779 - Endangered and Threatened Wildlife and Plants; Removal of the Concho Water Snake From the Federal...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-27

    ...Wildlife and Plants; Removal of the Concho Water Snake From the Federal List of Endangered...Wildlife and Plants; Removal of the Concho Water Snake From the Federal List of Endangered...commercial data indicate that the Concho water snake (Nerodia paucimaculata), a...

  14. SEMANTICBASED DECOMPOSITION OF

    E-print Network

    Ray, Indrakshi

    1 SEMANTIC­BASED DECOMPOSITION OF TRANSACTIONS Paul Ammann, Sushil Jajodia, Indrakshi Ray Center on providing algorithms necessary to implement a decomposition supplied by the database application developer and pays relatively little attention to what constitutes a desirable decomposition or how the developer

  15. Relational decomposition Lennart Beringer

    E-print Network

    Singh, Jaswinder Pal

    Relational decomposition Lennart Beringer Department of Computer Science, Princeton University, 35 decomposition, a technique for formally re- ducing termination-insensitive relational program logics to unary decomposition is applica- ble across heterogeneous pairs of transition systems. We apply our approach to justify

  16. Best Management Practices (BMP) plan for potable water discharges Y-12 Plant

    SciTech Connect

    Wiest, M.C. Jr.

    1995-07-01

    This plan provides guidance to minimize the environmental effects from discharges of chlorinated waters, including: Flushing of potable water lines; Releases from fire hydrants during testing and maintenance of fire protection systems; Releases from sprinkler systems for maintenance or testing purposes; and Other significant releases of chlorinated water. This BMP plan is intended to meet the Y-12 Plant National Pollutant Discharge Elimination System (NPDES) permit condition, requiring that BWs be used for flushing potable water lines and similar activities. Close adherence to the steps provided in this plan will help prevent the discharge of chlorinated waters ``in concentrations sufficient to be hazardous or otherwise detrimental to humans, livestock, wildlife, plant life, or fish and aquatic life in the receiving stream``.

  17. Effect of Industrial Effluents of Zob-Ahan on Soil, Water and Vegetable Plants

    NASA Astrophysics Data System (ADS)

    Rahmani, Hamid Reza; Rezaei, Mosleheddin

    Monitoring harmful chemicals especially heavy metals in industrial effluent for prevention and degradation of natural resources are required. The Effluent Water (EW) of Zob-Ahan (steel industrial complex), were seasonally collected, three times during 48 h period. The soils, well-water and vegetable plant samples were collected in land irrigated with EW and soil in adjacent virgin lands. The EW EC, TDS, BOD, COD, sulfate, chloride, bicarbonate and N-NO3 and of Cd, Co and Cr were above permissible limit, wells-water for in the down side of evaporation ponds EC, TDS, N-NO3, sulfate, chloride, bicarbonate and concentration of Cu, Co, Fe and Cr were above permissible limit and the soils treated with EW Zn, Mn and Cd concentration were in critical range. Soils irrigated with EW had higher OC content and available concentration of Cd, Fe, Cu, Mn, Zn and Pb compared to control sample (adjacent virgin land). In vegetable plants, all measured heavy metals concentration (except Cu content in Taree Irani that was in critical rang) was in normal range. The heavy metals concentration in unwashed plant samples were higher than washed ones. The results showed that Zob-Ahan EW has limitation for application as irrigation water, discharge into surface and subsurface water. Therefore, the EW, should properly be treated before discharging into environment. The heavy metals in soil and well-water affected by EW and irrigated plants with EW should regularly and closely be monitored.

  18. Response of Thematic Mapper bands to plant water stress

    NASA Technical Reports Server (NTRS)

    Cibula, W. G.; Zetka, E. F.; Rickman, D. L.

    1992-01-01

    Changes in leaf reflectance as water content decreases have been hypothesized to occur in the 1.55-1.75 and 2.08-2.35 micron wavelength regions. To evaluate this hypothesis, studies were conducted on ryegrass (Lolium multiflorum Lam.) and oats (Avena sativa L.), which were grown in a controlled, outdoor situation. Both fully-watered control beds and water-stressed beds were periodically examined with a spectroradiometer calibrated against a reflectance reference of polytetrafluoroethylene. The observed changes correspond to those predicted by stochastic leaf models employed by other investigators (leaf reflection increases in the 1.55-1.75 micron region as leaf water content decreases). Although the percentage changes in TM bands 1-3 are nearly as great as those found in TM bands 5 and 7, the absolute values of reflectance change are much lower. It is believed that these patterns are probably characteristic of a broad range of vegetation types. In terms of phenomena detection, these patterns should be considered in any practical remote sensing sensor scenario.

  19. Water Savings in Food Processing Plants - Potentials and Case Studies 

    E-print Network

    Trueblood, A; Ritchie, M.; Chow, S.; Ganji, A.

    2015-01-01

    the sequencing schedule of their grape presses, minimized the number of presses that operate per day, reducing total washdown water. ESL-IE-15-06-25 Proceedings of the Thrity-Seventh Industrial Energy Technology Conference New Orleans, LA. June 2-4, 2015 Case...

  20. Effects of Produced Water on Soil Characteristics, Plant Biomass, and Secondary Metabolites.

    PubMed

    Burkhardt, Andy; Gawde, Archana; Cantrell, Charles L; Baxter, Holly L; Joyce, Blake L; Stewart, C Neal; Zheljazkov, Valtcho D

    2015-11-01

    The Powder River Basin in Wyoming and Montana contains the United States' largest coal reserve. The area produces large amounts of natural gas through extraction from water-saturated coalbeds. Determining the impacts of coalbed natural gas-produced efflux water on crops is important when considering its potential use as supplemental irrigation water. We hypothesized that coalbed natural gas water, because of its high salinity and sodicity, would affect plant secondary metabolism (essential oils) and biomass accumulation. A 2-yr field study was conducted in Wyoming to investigate the effects of produced water on two traditional bioenergy feedstocks-corn ( L.) and switchgrass ( L.)-and four novel biofuel feedstock species-spearmint ( L.), Japanese cornmint ( L.), lemongrass [ (Nees ex Steud.) J.F. Watson]), and common wormwood ( L.). The four nontraditional feedstock species were chosen because they contain high-value plant chemicals that can offset production costs. Essential oil content was significantly affected by coalbed natural gas water in lemongrass and spearmint. Oil content differences between two spearmint harvests in the same year indicated that there were significant changes between the growth stage of the plant and essential oil content; the first harvest averaged 0.42 g of oil per 100 g biomass while the second harvest (harvested before flowering) yielded only 0.19 g oil per 100 g dry biomass. Results indicated that produced water can be used for short-period (2 yr) irrigation of crops. However, prolonged use of untreated produced water for irrigation would likely have deleterious long-term effects on the soil and plants unless the water was treated or diluted (mixed) with good-quality water. PMID:26641346

  1. Where do roots take up water? Neutron radiography of water flow into the roots of transpiring plants growing in soil.

    PubMed

    Zarebanadkouki, Mohsen; Kim, Yangmin X; Carminati, Andrea

    2013-09-01

    Where and how fast does water flow from soil into roots? The answer to this question requires direct and in situ measurement of local flow of water into roots of transpiring plants growing in soil. We used neutron radiography to trace the transport of deuterated water (D?O) in lupin (Lupinus albus) roots. Lupins were grown in aluminum containers (30 × 25 × 1 cm) filled with sandy soil. D?O was injected in different soil regions and its transport in soil and roots was monitored by neutron radiography. The transport of water into roots was then quantified using a convection-diffusion model of D?O transport into roots. The results showed that water uptake was not uniform along roots. Water uptake was higher in the upper soil layers than in the lower ones. Along an individual root, the radial flux was higher in the proximal segments than in the distal segments. In lupins, most of the water uptake occurred in lateral roots. The function of the taproot was to collect water from laterals and transport it to the shoot. This function is ensured by a low radial conductivity and a high axial conductivity. Lupin root architecture seems well designed to take up water from deep soil layers. PMID:23692148

  2. Reducing water use and wastewater in food processing plants: How one company cut costs

    SciTech Connect

    Carawan, R.E.; Waynick, J.B.

    1991-12-31

    Many food processing plants today are literaly washing profits down the drain. This industry typically uses a large volume of water to process food products and clean plant equipment, yielding large amounts of wastewater that must be treated. This publication discusses how one food processing company became aware of its wastewater problems and reduced costly waste with assistance from the North Carolina Cooperative Extension Service and the North Carolina Pollution Prevention Program.

  3. Land disposal of water treatment plant sludge -- A feasibility analysis

    SciTech Connect

    Viraraghavan, T.; Multon, L.M.; Wasylenchuk, E.J.

    1998-07-01

    In this study, the following alternative disposal methods for the Buffalo Pound Water Treatment Sludge were evaluated: landfilling, discharge into sanitary sewers, long-term lagooning, use in manufacturing, co-composting, alum recovery and land application. Land application was chosen at the best disposal alternative. Preliminary design resulted in a 1% dry alum sludge loading rate (25 tonnes/ha), requiring 35 ha over a nine-year period and a phosphorus fertilizer supplement of about 50kg/ha.

  4. Engineering plants to reflect light: strategies for engineering water-efficient plants to adapt to a changing climate.

    PubMed

    Zamft, Bradley M; Conrado, Robert J

    2015-09-01

    Population growth and globally increasing standards of living have put a significant strain on the energy-food-water nexus. Limited water availability particularly affects agriculture, as it accounts for over 70% of global freshwater withdrawals (Aquastat). This study outlines the fundamental nature of plant water consumption and suggests a >50% reduction in renewable freshwater demand is possible by engineering more reflective crops. Furthermore, the decreased radiative forcing resulting from the greater reflectivity of crops would be equivalent to removing 10-50 ppm CO2 from the atmosphere. Recent advances in engineering optical devices and a greater understanding of the mechanisms of biological reflectance suggest such a strategy may now be viable. Here we outline the challenges involved in such an effort and suggest three potential approaches that could enable its implementation. While the local benefits may be straightforward, determining the global externalities will require careful modelling efforts and gradually scaled field trials. PMID:25923193

  5. Emergency membrane contactor based absorption system for ammonia leaks in water treatment plants.

    PubMed

    Shao, Jiahui; Fang, Xuliang; He, Yiliang; Jin, Qiang

    2008-01-01

    Abstract Because of the suspected health risks of trihalomethanes (THMs), more and more water treatment plants have replaced traditional chlorine disinfection process with chloramines but often without the proper absorption system installed in the case of ammonia leaks in the storage room. A pilot plant membrane absorption system was developed and installed in a water treatment plant for this purpose. Experimentally determined contact angle, surface tension, and corrosion tests indicated that the sulfuric acid was the proper choice as the absorbent for leaking ammonia using polypropylene hollow fiber membrane contactor. Effects of several operating conditions on the mass transfer coefficient, ammonia absorption, and removal efficiency were examined, including the liquid concentration, liquid velocity, and feed gas concentration. Under the operation conditions investigated, the gas absorption efficiency over 99.9% was achieved. This indicated that the designed pilot plant membrane absorption system was effective to absorb the leaking ammonia in the model storage room. The removal rate of the ammonia in the model storage room was also experimentally and theoretically found to be primarily determined by the ammonia suction flow rate from the ammonia storage room to the membrane contactor. The ammonia removal rate of 99.9% was expected to be achieved within 1.3 h at the ammonia gas flow rate of 500 m3/h. The success of the pilot plant membrane absorption system developed in this study illustrated the potential of this technology for ammonia leaks in water treatment plant, also paved the way towards a larger scale application. PMID:19143342

  6. Plant response to the soil environment: An analytical model integrating yield, water, soil type, and salinity

    NASA Astrophysics Data System (ADS)

    Shani, Uri; Ben-Gal, Alon; Tripler, Effi; Dudley, Lynn M.

    2007-08-01

    An accessible solution capable of reliably predicting plant-environmental interrelationships for variable species, climates, soils, and management options is a necessary tool for creating sustainable agriculture and environmental preservation. A mechanism-based analytical solution, the first of its kind that considers multiple environmental variables and their combined effects on plant response, was developed and tested. Water uptake by plants, water and salt leakage below the roots, and yield are calculated by solving for transpiration in a single mathematical expression according to limitations imposed by root zone salinity and water status. Input variables include the quantity and salinity of applied water, terms for plant sensitivity to salinity and to water stress, potential evapotranspiration, and soil hydraulic parameters. Where water was not limiting, regression of predicted versus measured data resulted in r2 = 0.96 with slope of 0.937 and intercept of 0.033 (not different from 1 and 0 at 99% confidence), where irrigation varied and salinity was not limiting the r2 = 0.94 with slope of 0.906 and intercept of 0.044 (not different from 1 and 0 at 99% confidence), where both salinity and water levels varied r2 = 0.94 with slope of 0.966 and intercept of 0.033 (not different from 1 and 0 at 99% confidence). Application of the model for agricultural and environmental management and economic analysis is discussed. For example, a farmer in the Arava in Israel where irrigation water salinity is high (electrical conductivity of 3 dS m-1) cannot expect to reach greater than 70% of the potential yield for a pepper crop with any amount of irrigation. By choosing melon, the farmer can achieve 90% of potential yield with the same quality and quantity of water.

  7. Use of Gold Nanoparticles to Detect Water Uptake in Vascular Plants

    PubMed Central

    Hwang, Bae Geun; Ahn, Sungsook; Lee, Sang Joon

    2014-01-01

    Direct visualization of water-conducting pathways and sap flows in xylem vessels is important for understanding the physiology of vascular plants and their sap ascent. Gold nanoparticles (AuNPs) combined with synchrotron X-ray imaging technique is a new promising tool for investigating plant hydraulics in opaque xylem vessels of vascular plants. However, in practical applications of AuNPs for real-time quantitative visualization of sap flows, their interaction with a vascular network needs to be verified in advance. In this study, the effect of AuNPs on the water-refilling function of xylem vessels is experimentally investigated with three monocot species. Discrepancy in the water uptakes starts to appear at about 20 min to 40 min after the supply of AuNP solution to the test plant by the possible gradual accumulation of AuNPs on the internal structures of vasculature. However conclusively, it is observed that the water-refilling speeds in individual xylem vessels are virtually unaffected by hydrophilically surface-modified AuNPs (diameter ?20 nm). Therefore, the AuNPs can be effectively used as flow tracers in the xylem vessels in the first 20?30 min without any physiological barrier. As a result, AuNPs are found to be useful for visualizing various fluid dynamic phenomena occurring in vascular plants. PMID:25502567

  8. Minimal watering regime impacts on desert adapted green roof plant performance

    NASA Astrophysics Data System (ADS)

    Kovachich, S.; Pavao-Zuckerman, M.; Templer, S.; Livingston, M.; Stoltz, R.; Smith, S.

    2011-12-01

    Roof tops can cover one-fifth of urban areas and can greatly alter the movement of matter and energy in cities. With traditional roofing methods and materials, roof tops readily absorb heat and as a result, buildings and the surrounding urban area heat to unnaturally high temperatures. It is hypothesized that extensive green roofs would have wide-ranging benefits for arid environments. However, little is known about the cost of water use associated with green roof installations and how to balance energy reduction needs with water costs in this water limited environment. We are conducting a pilot study to test whether a) green roofs with native plants and environmentally-responsible watering regimes will prove successful in arid environments and if b) green roofs provide ecosystem services with responsible water application. Three species of Sonoran Desert natives, Dyssodia pentachaeta (groundcover), Calliandra eriophylla (shrub), and Hesperaloe parviflora (succulent) have been planted in experimental plots [1 m2 model houses and roofs, replicated in triplicate] with two sandy, rocky desert soil mixtures (light mix: 60% expanded shale and heavy mix: organic and sandy mix with 50% shale) at the Biosphere 2 campus near Oracle, Az. The green roofs are watered by two different techniques. The first technique provides "smart watering", the minimal amount of water needed by green roof plants based on precipitation and historical data. The second watering technique is considered heavy and does not take into account environmental conditions. Preliminary data from the experimental plots shows a 30% decrease in daytime roof top temperatures on green roofs and a 10% decrease in interior temperatures in buildings with green roofs. This trend occurs with both watering regimes (heavy and light). This finding suggests that additional irrigation yields no extra heat reduction and energy savings. In order to explain this phenomenon more clearly, we use co-located temperature and soil moisture readings on each green roof to analyze the spatial and temporal covariance of water and temperature. We link these patterns in soil moisture to measures of plant performance with weekly hyperspectral images (NDVI - Normalized Difference Vegetation Index) of each green roof. The data will allow us to determine the minimal amount of water use required for successful green roofs and healthy green roof plants. Preliminary data from a five week pilot study in the 2011 summer monsoon has shown a variation in NDVI by species. H. parviflora displayed the highest NDVI values, while D. pentachaeta and C. eriophylla shared similar, lower NDVI values. In general, the comparison of soil moisture and NDVI values expressed a very weak positive relationship but stronger species specific responses. D. pentachaeta demonstrated the strongest response to soil water and H. parviflora displayed the weakest response.

  9. IMPROVING PLANT'S TOLERANCE TO WATER STRESS BY MOLECULAR PLANT BREEDING AND GENETIC TRANSFORMATION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil flooding affects plant growth and productivity. Flooding causes premature sensecence: leaf chlorosis, necrosis, defoliation, cessation of growth and reduced yield. This study was conducted to identify quantitative trait loci (QTL) associated with tolerance of soybean to soil waterlogging. Two r...

  10. Water soluble carbon nano-onions from wood wool as growth promoters for gram plants

    NASA Astrophysics Data System (ADS)

    Sonkar, Sumit Kumar; Roy, Manas; Babar, Dipak Gorakh; Sarkar, Sabyasachi

    2012-11-01

    Water-soluble carbon nano-onions (wsCNOs) isolated from wood wool--a wood-based pyrolysis waste product of wood, can enhance the overall growth rate of gram (Cicer arietinum) plants. Treatment of plants with upto 30 ?g mL-1 of wsCNOs for an initial 10 day period in laboratory conditions led to an increase in the overall growth of the plant biomass. In order to examine the growth stimulating effects of wsCNOs under natural conditions, 10 day-old plants treated with and without wsCNOs were transplanted into soil of standard carbon and nitrogen composition. We observed an enhanced growth rate of the wsCNOs pre-treated plants in soil, which finally led to an increased productivity of plants in terms of a larger number of grams. On analyzing the carbon, hydrogen, and nitrogen (CHN) content for the shoot and fruit sections of the plants treated with and without wsCNOs, only a minor difference in the composition was noticed. However, a slight increase in the percentage of carbon and hydrogen in shoots reflects the synthesis of more organic biomass in the case of treated plants. This work shows that wsCNOs are non-toxic to plant cells and can act as efficient growth stimulants which can be used as benign growth promoters.

  11. A novel system for spatial and temporal imaging of intrinsic plant water use efficiency.

    PubMed

    McAusland, L; Davey, P A; Kanwal, N; Baker, N R; Lawson, T

    2013-11-01

    Instrumentation and methods for rapid screening and selection of plants with improved water use efficiency are essential to address current issues of global food and fuel security. A new imaging system that combines chlorophyll fluorescence and thermal imaging has been developed to generate images of assimilation rate (A), stomatal conductance (gs), and intrinsic water use efficiency (WUEi) from whole plants or leaves under controlled environmental conditions. This is the first demonstration of the production of images of WUEi and the first to determine images of g s from themography at the whole-plant scale. Data are presented illustrating the use of this system for rapidly and non-destructively screening plants for alterations in WUEi by comparing Arabidopsis thaliana mutants (OST1-1) that have altered WUEi driven by open stomata, with wild-type plants. This novel instrument not only provides the potential to monitor multiple plants simultaneously, but enables intra- and interspecies variation to be taken into account both spatially and temporally. The ability to measure A, gs, and WUEi progressively was developed to facilitate and encourage the development of new dynamic protocols. Images illustrating the instrument's dynamic capabilities are demonstrated by analysing plant responses to changing photosynthetic photon flux density (PPFD). Applications of this system will augment the research community's need for novel screening methods to identify rapidly novel lines, cultivars, or species with improved A and WUEi in order to meet the current demands on modern agriculture and food production. PMID:24043857

  12. A novel system for spatial and temporal imaging of intrinsic plant water use efficiency

    PubMed Central

    Lawson, T.

    2013-01-01

    Instrumentation and methods for rapid screening and selection of plants with improved water use efficiency are essential to address current issues of global food and fuel security. A new imaging system that combines chlorophyll fluorescence and thermal imaging has been developed to generate images of assimilation rate (A), stomatal conductance (g s), and intrinsic water use efficiency (WUEi) from whole plants or leaves under controlled environmental conditions. This is the first demonstration of the production of images of WUEi and the first to determine images of g s from themography at the whole-plant scale. Data are presented illustrating the use of this system for rapidly and non-destructively screening plants for alterations in WUEi by comparing Arabidopsis thaliana mutants (OST1-1) that have altered WUEi driven by open stomata, with wild-type plants. This novel instrument not only provides the potential to monitor multiple plants simultaneously, but enables intra- and interspecies variation to be taken into account both spatially and temporally. The ability to measure A, g s, and WUEi progressively was developed to facilitate and encourage the development of new dynamic protocols. Images illustrating the instrument’s dynamic capabilities are demonstrated by analysing plant responses to changing photosynthetic photon flux density (PPFD). Applications of this system will augment the research community’s need for novel screening methods to identify rapidly novel lines, cultivars, or species with improved A and WUEi in order to meet the current demands on modern agriculture and food production. PMID:24043857

  13. Agrochemical control of plant water use using engineered abscisic acid receptors.

    PubMed

    Park, Sang-Youl; Peterson, Francis C; Mosquna, Assaf; Yao, Jin; Volkman, Brian F; Cutler, Sean R

    2015-04-23

    Rising temperatures and lessening fresh water supplies are threatening agricultural productivity and have motivated efforts to improve plant water use and drought tolerance. During water deficit, plants produce elevated levels of abscisic acid (ABA), which improves water consumption and stress tolerance by controlling guard cell aperture and other protective responses. One attractive strategy for controlling water use is to develop compounds that activate ABA receptors, but agonists approved for use have yet to be developed. In principle, an engineered ABA receptor that can be activated by an existing agrochemical could achieve this goal. Here we describe a variant of the ABA receptor PYRABACTIN RESISTANCE 1 (PYR1) that possesses nanomolar sensitivity to the agrochemical mandipropamid and demonstrate its efficacy for controlling ABA responses and drought tolerance in transgenic plants. Furthermore, crystallographic studies provide a mechanistic basis for its activity and demonstrate the relative ease with which the PYR1 ligand-binding pocket can be altered to accommodate new ligands. Thus, we have successfully repurposed an agrochemical for a new application using receptor engineering. We anticipate that this strategy will be applied to other plant receptors and represents a new avenue for crop improvement. PMID:25652827

  14. Meta-Analysis of the Copper, Zinc, and Cadmium Absorption Capacities of Aquatic Plants in Heavy Metal-Polluted Water

    PubMed Central

    Li, Jing; Yu, Haixin; Luan, Yaning

    2015-01-01

    The use of aquatic plants for phytoremediation is an important method for restoring polluted ecosystems. We sought to analyze the capacity of different aquatic plant species to absorb heavy metals and to summarize available relevant scientific data on this topic. We present a meta-analysis of Cu, Zn, and Cd absorption capacities of aquatic plants to provide a scientific basis for the selection of aquatic plants suitable for remediation of heavy-metal pollution. Plants from the Gramineae, Pontederiaceae, Ceratophyllaceae, Typhaceae and Haloragaceae showed relatively strong abilities to absorb these metals. The ability of a particular plant species to absorb a given metal was strongly correlated with its ability to absorb the other metals. However, the absorption abilities varied with the plant organ, with the following trend: roots > stems > leaves. The pH of the water and the life habits of aquatic plants (submerged and emerged) also affect the plant’s ability to absorb elements. Acidic water aids the uptake of heavy metals by plants. The correlation observed between element concentrations in plants with different aquatic life habits suggested that the enrichment mechanism is related to the surface area of the plant exposed to water. We argue that this meta-analysis would aid the selection of aquatic plants suitable for heavy-metal absorption from polluted waters. PMID:26703632

  15. Water and Heat Balance Model for Predicting Drainage Below the Plant Root Zone

    Energy Science and Technology Software Center (ESTSC)

    1989-11-01

    UNSAT-H Version 2.0 is a one-dimensional model that simulates the dynamic processes of infiltration, drainage, redistribution, surface evaporation, and the uptake of water from soil by plants. The model was developed for assessing the water dynamics of arid sites used or proposed for near-surface waste disposal. In particular, the model is used for simulating the water balance of cover systems over buried waste and for estimating the recharge rate (i.e., the drainage rate beneath themore »plant root zone when a sizable vadose zone is present). The mathematical base of the model are Richards'' equation for water flow, Ficks'' law for vapor diffusion, and Fouriers law for heat flow. The simulated profile can be homogeneous or layered. The boundary conditions can be controlled as either constant (potential or temperature) or flux conditions to reflect actual conditions at a given site.« less

  16. Bivalve fouling of nuclear power plant service-water systems. Volume 1. Correlation of bivalve biological characteristics and raw-water system design

    SciTech Connect

    Neitzel, D.A.; Johnson, K.I.; Page, T.L.; Young, J.S.; Daling, P.M.

    1984-12-01

    Fouling of raw-water systems in nuclear power plants in the US can affect the safe operation of a power plant. This report describes correlations between the biology of bivalve organisms and the design and operation of power plants that allow bivalves to enter and reside in nuclear power plants. Discussions are focused on safety-related raw-water systems subject to fouling by the Asiatic clam (Corbicula fluminea), the blue mussel (Mytilus edulis), and the American oyster (Crassostrea virginica). Score sheets to rate fouling potential of power plant systems and components are provided.

  17. Evaluation of Impacts on Energy and Plant Profitability of Responses to Water Curtailment 

    E-print Network

    Ferland, K.

    2015-01-01

    for process cooling in cooling tower over 12 month period with no curtailment defines Business as Usual (BAU) and sets the baseline for plant net profitability, water use and energy use. Basis of calculating Monthly Average Water Use. • Curtailment limits... scenario, expenses also include the annualized equipment cost, as well as operational costs associated with the technology (pump and fan electricity). For any scenario which resulted in a reduction in production from BAU, a penalty of 10% of cost...

  18. Water filtration problems at the Idaho Chemical Processing Plant Fuel Storage Area

    SciTech Connect

    Christensen, A.B.; Childs, K.F.; Wolfram, J.H.

    1988-01-01

    The new fuel storage area (FSA) began operation at the Idaho Chemical Processing Plant in mid-1984. The FSA water treatment system is designed to provide a high standard of purity to the storage pool water. The filters, which are an important part of this system, have shown a tendency to foul during the last 4 yr. The cause of the filter fouling and the steps taken to prevent it are described in this paper.

  19. Invertebrate grazers affect metal/metalloid fixation during litter decomposition.

    PubMed

    Schaller, Jörg; Brackhage, Carsten

    2015-01-01

    Plant litter and organic sediments are main sinks for metals and metalloids in aquatic ecosystems. The effect of invertebrates as key species in aquatic litter decomposition on metal/metalloid fixation by organic matter is described only for shredders, but for grazers as another important animal group less is known. Consequently, a laboratory batch experiment was conducted to examine the effect of invertebrate grazers (Lymnaea stagnalis L.) on metal/metalloid fixation/remobilization during aquatic litter decomposition. It could be shown that invertebrate grazers facilitate significantly the formation of smaller sizes of particulate organic matter (POM), as shown previously for invertebrate shredders. The metal/metalloid binding capacity of these smaller particles of POM is higher compared to leaf litter residuals. But element enrichment is not as high as shown previously for the effect by invertebrate shredders. Invertebrate grazers enhance also the mobilization of selected elements to the water, in the range also proven for invertebrate shredders but different for the different elements. Nonetheless invertebrate grazers activity during aquatic litter decomposition leads to a metal/metalloid fixation into leaf litter as part of sediment organic matter. Hence, the effect of invertebrate grazers on metal/metalloid fixation/remobilization contrasts partly with former assessments revealing the possibility of an enhanced metal/metalloid fixation. PMID:25063962

  20. The avoidance strategy of environmental constraints by an aquatic plant Potamogeton alpinus in running waters

    PubMed Central

    Robionek, Alicja; Bana?, Krzysztof; Chmara, Rafa?; Szmeja, Józef

    2015-01-01

    Aquatic plants anchored in streams are under pressure from various constraints linked to the water flow and display strategies to prevent their damage or destruction. We assume that the responses of aquatic plants to fast-water flow are a manifestation of a trade-off consisting in either maximizing the resistance to damage (tolerance strategy) in minimizing the hydrodynamic forces (avoidance strategy), or both. Our main hypothesis was that Potamogeton alpinus demonstrate the avoidance strategy. We analyzed architecture traits of the modules of this clonal plant from slow- and fast-flowing streams. In fast-flowing waters, the avoidance strategy of P. alpinus is reflected by the following: (1) the presence of floating leaves that stabilize the vertical position of the stem and protect the inflorescence against immersion; (2) elongation of submerged leaves (weakens the pressure of water); and (3) shoot diameter reduction and increase in shoot density (weakens the pressure of water, increases shoot elasticity), and by contrast in slow-water flow include the following: (4) the absence of floating leaves in high intensity of light (avoiding unnecessary outlays on a redundant organ); (5) the presence of floating leaves in low intensity of light (avoidance of stress caused by an insufficient assimilation area of submerged leaves). PMID:26380667

  1. The avoidance strategy of environmental constraints by an aquatic plant Potamogeton alpinus in running waters.

    PubMed

    Robionek, Alicja; Bana?, Krzysztof; Chmara, Rafa?; Szmeja, Józef

    2015-08-01

    Aquatic plants anchored in streams are under pressure from various constraints linked to the water flow and display strategies to prevent their damage or destruction. We assume that the responses of aquatic plants to fast-water flow are a manifestation of a trade-off consisting in either maximizing the resistance to damage (tolerance strategy) in minimizing the hydrodynamic forces (avoidance strategy), or both. Our main hypothesis was that Potamogeton alpinus demonstrate the avoidance strategy. We analyzed architecture traits of the modules of this clonal plant from slow- and fast-flowing streams. In fast-flowing waters, the avoidance strategy of P. alpinus is reflected by the following: (1) the presence of floating leaves that stabilize the vertical position of the stem and protect the inflorescence against immersion; (2) elongation of submerged leaves (weakens the pressure of water); and (3) shoot diameter reduction and increase in shoot density (weakens the pressure of water, increases shoot elasticity), and by contrast in slow-water flow include the following: (4) the absence of floating leaves in high intensity of light (avoiding unnecessary outlays on a redundant organ); (5) the presence of floating leaves in low intensity of light (avoidance of stress caused by an insufficient assimilation area of submerged leaves). PMID:26380667

  2. Water use in the development and operation of geothermal power plants.

    SciTech Connect

    Clark, C. E.; Harto, C. B.; Sullivan, J. L.; Wang, M. Q.

    2010-09-17

    Geothermal energy is increasingly recognized for its potential to reduce carbon emissions and U.S. dependence on foreign oil. Energy and environmental analyses are critical to developing a robust set of geothermal energy technologies. This report summarizes what is currently known about the life cycle water requirements of geothermal electric power-generating systems and the water quality of geothermal waters. It is part of a larger effort to compare the life cycle impacts of large-scale geothermal electricity generation with other power generation technologies. The results of the life cycle analysis are summarized in a companion report, Life Cycle Analysis Results of Geothermal Systems in Comparison to Other Power Systems. This report is divided into six chapters. Chapter 1 gives the background of the project and its purpose, which is to inform power plant design and operations. Chapter 2 summarizes the geothermal electricity generation technologies evaluated in this study, which include conventional hydrothermal flash and binary systems, as well as enhanced geothermal systems (EGS) that rely on engineering a productive reservoir where heat exists but water availability or permeability may be limited. Chapter 3 describes the methods and approach to this work and identifies the four power plant scenarios evaluated: a 20-MW EGS plant, a 50-MW EGS plant, a 10-MW binary plant, and a 50-MW flash plant. The two EGS scenarios include hydraulic stimulation activities within the construction stage of the life cycle and assume binary power generation during operations. The EGS and binary scenarios are assumed to be air-cooled power plants, whereas the flash plant is assumed to rely on evaporative cooling. The well field and power plant design for the scenario were based on simulations using DOE's Geothermal Economic Technology Evaluation Model (GETEM). Chapter 4 presents the water requirements for the power plant life cycle for the scenarios evaluated. Geology, reservoir characteristics, and local climate have various effects on elements such as drilling rate, the number of production wells, and production flow rates. Over the life cycle of a geothermal power plant, from construction through 30 years of operation, plant operations is where the vast majority of water consumption occurs. Water consumption refers to the water that is withdrawn from a resource such as a river, lake, or non-geothermal aquifer that is not returned to that resource. For the EGS scenarios, plant operations consume between 0.29 and 0.72 gal/kWh. The binary plant experiences similar operational consumption, at 0.27 gal/kWh. Far less water, just 0.01 gal/kWh, is consumed during operations of the flash plant because geofluid is used for cooling and is not replaced. While the makeup water requirements are far less for a hydrothermal flash plant, the long-term sustainability of the reservoir is less certain due to estimated evaporative losses of 14.5-33% of produced geofluid at operating flash plants. For the hydrothermal flash scenario, the average loss of geofluid due to evaporation, drift, and blowdown is 2.7 gal/kWh. The construction stage requires considerably less water: 0.001 gal/kWh for both the binary and flash plant scenarios and 0.01 gal/kWh for the EGS scenarios. The additional water requirements for the EGS scenarios are caused by a combination of factors, including lower flow rates per well, which increases the total number of wells needed per plant, the assumed well depths, and the hydraulic stimulation required to engineer the reservoir. Water quality results are presented in Chapter 5. The chemical composition of geofluid has important implications for plant operations and the potential environmental impacts of geothermal energy production. An extensive dataset containing more than 53,000 geothermal geochemical data points was compiled and analyzed for general trends and statistics for typical geofluids. Geofluid composition was found to vary significantly both among and within geothermal fields. Seven main chemical constituents were found to

  3. Water availability and the competitive effect of a columnar cactus on its nurse plant

    NASA Astrophysics Data System (ADS)

    Flores-Martínez, Arturo; Ezcurra, Exequiel; Sánchez-Colón, Salvador

    1998-02-01

    A field study was conducted in a semi-arid tropical ecosystem in Mexico to test whether competition for soil water is the causal mechanism underlying the negative effect of the columnar cactus Neobuxbaumia tetetzo on its nurse plant Mimosa luisana and to examine how this relationship varies over time. The effect of irrigation was evaluated by recording the production of leaves, modules (i.e. internodes with an axillary bud), inflorescences and fruits in shrubs growing either isolated or associated with juvenile or adult columnar cacti. 4 001 of water, in five doses of 801 each every 15 d, were added to the treatment plants; no water other than rainfall was added to control plants. Additionally, to evaluate how the effect of the columnar cacti on the shrubs may vary among years we made a comparison of the production of plant structures between 2 years of contrasting rainfall. The irrigation treatment increased the production of modules, inflorescences and fruits, but not of leaves. Shrub response to watering was also dependent on class of association: those associated with juvenile cacti showed a higher response to irrigation than any other treatment. Our results show that water addition increases the production of structures and partially reduces the negative effect of the cactus on nurse shrub, thus supporting the hypothesis of competition for water. The negative effect of the cacti on their nurse plants was present during both years of observations, but the intensity of the negative effect varies from relatively wet to dry years. The results are discussed in relation to how temporal changes in resource availability affect the results of competitive interactions and the importance of this mechanism in the structure and dynamics of this dryland community.

  4. Effect of plant water deficit on the deoxynivalenol concentration in Fusarium-infected maize kernels.

    PubMed

    Oldenburg, Elisabeth; Schittenhelm, Siegfried

    2012-11-01

    In current climate change scenarios, mean air temperatures and summer droughts are expected to increase over the long-term average in large parts of Europe. These changes will strongly affect the growth and health of cultivated plants. In a field experiment in 2009 and 2010 in rain-out shelters, the consequences of plant water availability under three water regimes on the severity of Fusarium ear rot, deoxynivalenol (DON) contamination and yield of maize were investigated. Water was provided exclusively to the plants by a mobile sprinkler system installed in the rain-out shelter. Three maize cultivars were supplied with 50, 75, and 125% of the long-term average monthly precipitation of the experimental site. In 2009, Fusarium graminearum-infected oat kernels were placed on the soil surrounding maize plants to promote ear infection, whereas in 2010, the maize silks were directly inoculated with suspensions of F. graminearum conidia. Heavy drought stress in the 50% water regime was reflected in the average ear yield of the three maize cultivars of 75 dt ha(-1) compared with 192 dt ha(-1) at 125% water. In this comparison, the DON concentrations in the kernels were fivefold higher at 50% water than at the high water regime: 380 compared with 75 ?g DON kg(-1) DM. In 2010, the drought stress symptoms were less pronounced than in 2009, and a much lower ear yield loss from 128 to 108 dt DM ha(-1) was observed with decreasing water supply. The DON contamination of the kernels was at a higher level than in 2009, but a similar upward trend from 330 ?g kg(-1) DM at 125% water supply to about 3.5-fold higher DON levels at 75 and 50% water supply was observed. These different yield responses presumably resulted from variable climatic conditions at the experimental site in the 2 years. The results of this study suggest that the risk of DON contamination of maize kernels increases when plants are grown under conditions of long-term water deficit. PMID:23606194

  5. Potential of using plant extracts for purification of shallow well water in Malawi

    NASA Astrophysics Data System (ADS)

    Pritchard, M.; Mkandawire, T.; Edmondson, A.; O'Neill, J. G.; Kululanga, G.

    There has been very little scientific research work into the use of plant extracts to purify groundwater. Research studies on the purification of groundwater have mainly been carried out in developed countries and have focused on water purification systems using aluminium sulphate (a coagulant) and chlorine (a disinfectant). Such systems are expensive and not viable for rural communities due to abject poverty. Shallow well water, which is commonly available throughout Africa, is often grossly contaminated and usually consumed untreated. As a result, water-related diseases kill more than 5 million people every year worldwide. This research was aimed at examining natural plant extracts in order to develop inexpensive ways for rural communities to purify their groundwater. The study involved creating an inventory of plant extracts that have been used for water and wastewater purification. A prioritisation system was derived to select the most suitable extracts, which took into account criteria such as availability, purification potential, yield and cost of extraction. Laboratory trials were undertaken on the most promising plant extracts, namely: Moringa oleifera, Jatropha curcas and Guar gum. The extracts were added to water samples obtained from five shallow wells in Malawi. The trials consisted of jar tests to assess the coagulation potential and the resulting effect on physico-chemical and microbiological parameters such as temperature, pH, turbidity and coliforms. The results showed that the addition of M. oleifera, J. curcas and Guar gum can considerably improve the quality of shallow well water. Turbidity reduction was higher for more turbid water. A reduction efficiency exceeding 90% was achieved by all three extracts on shallow well water that had a turbidity of 49 NTU. A reduction in coliforms was about 80% for all extracts. The pH of the water samples increased with dosage, but remained within acceptable levels for drinking water for all the extracts. Overall, M. oleifera powder produced superior results, followed by Guar gum and lastly J. curcas. There is a need to carry out further more detailed tests, which include toxicity to guarantee the safety of using plant extracts as a coagulant in the purification of drinking water for human consumption.

  6. Meta-Analysis of the Copper, Zinc, and Cadmium Absorption Capacities of Aquatic Plants in Heavy Metal-Polluted Water.

    PubMed

    Li, Jing; Yu, Haixin; Luan, Yaning

    2015-01-01

    The use of aquatic plants for phytoremediation is an important method for restoring polluted ecosystems. We sought to analyze the capacity of different aquatic plant species to absorb heavy metals and to summarize available relevant scientific data on this topic. We present a meta-analysis of Cu, Zn, and Cd absorption capacities of aquatic plants to provide a scientific basis for the selection of aquatic plants suitable for remediation of heavy-metal pollution. Plants from the Gramineae, Pontederiaceae, Ceratophyllaceae, Typhaceae and Haloragaceae showed relatively strong abilities to absorb these metals. The ability of a particular plant species to absorb a given metal was strongly correlated with its ability to absorb the other metals. However, the absorption abilities varied with the plant organ, with the following trend: roots > stems > leaves. The pH of the water and the life habits of aquatic plants (submerged and emerged) also affect the plant's ability to absorb elements. Acidic water aids the uptake of heavy metals by plants. The correlation observed between element concentrations in plants with different aquatic life habits suggested that the enrichment mechanism is related to the surface area of the plant exposed to water. We argue that this meta-analysis would aid the selection of aquatic plants suitable for heavy-metal absorption from polluted waters. PMID:26703632

  7. Plant Water Stress Detection Using Radar: The Influence Of Water Stress On Leaf Dielectric Properties

    NASA Astrophysics Data System (ADS)

    van Emmerik, Tim; Steele-Dunne, Susan; Judge, Jasmeet; van de Giesen, Nick

    2015-04-01

    Recent research on an agricultural maize canopy has demonstrated that leaf water content can change considerably during the day and in response to water stress. Model simulations suggest that these changes have a significant impact on radar backscatter, particularly in times of water stress. Radar is already used for several vegetation and soil monitoring applications, and might be used for water stress detection in agricultural canopies. Radar observations of the land surface are sensitive because it results in two-way attenuation of the reflected signal from the soil surface, and vegetation contributes to total backscatter from the canopy itself. An important driver that determines the impact of vegetation on backscatter is the dielectric constant of the leaves, which is primarily a function of their moisture content. Understanding the effects of water stress on the dynamics of leaf dielectric properties might shed light on how radar can be used to detect vegetation water stress. Previous studies have investigated the dielectric properties of vegetation. However, this has mainly been done using destructive sampling or in-vivo measurements of tree trunks. Unfortunately, few in-vivo measurements of leaf dielectric properties exist. This study presents datasets of in-vivo dielectric measurements of maize leaves, taken during two field experiments. One experiment was done using was done during a period of water stress, the other during a period without. Field measurements revealed a different vertical profile in dielectric properties for the period with and without water stress. During a period of increased water stress, the diurnal dynamics of leaves at different heights responded differently to a decrease in bulk moisture content. This study provides insight in the effect of water stress on leaf dielectric properties and water content, and highlights the potential use of radar for water stress detection in agricultural canopies.

  8. Ozone sensitivity in sweet corn (Zea mays L. ) plants: a possible relationship to water balance

    SciTech Connect

    Harris, M.J.; Heath, R.L.

    1981-10-01

    Stomatal characteristics affecting gas exchange were compared in two sweet corn hybrids (var. Bonanza and Monarch Advance) which differ in foliar ozone sensitivity. No significant differences were observed in stomatal frequencies, guard cell lengths, or conductances to water vapor diffusion. When plant water status was compared, leaf-water potentials for the ozone-resistant cultivar, Bonanza, were lower. A comparison of the relationship between soil- and leaf-water potential indicated that the leaf-water potential of Bonanza was more sensitive to declines in soil-water potential. Additionally, a comparison of stomatal conductance to water vapor diffusion as soil moisture declined and following root detachment indicated that stomata of Bonanza were, likewise, more sensitive to increasing water stress. Data suggest that these differences are attributable to a greater shoot-to-root fresh weight ratio and higher resistance to water movement in the water-conducting tissues for Bonanza. Our observations suggest that root and water delivery system characteristics play a major contributory role in the determination of foliar ozone sensitivity in this species.

  9. Ultraviolet-B radiation effects on water relations, leaf development, and photosynthesis in droughted pea plants

    PubMed

    Nogues; Allen; Morison; Baker

    1998-05-01

    The effects of ultraviolet-B (UV-B) radiation on water relations, leaf development, and gas-exchange characteristics in pea (Pisum sativum L. cv Meteor) plants subjected to drought were investigated. Plants grown throughout their development under a high irradiance of UV-B radiation (0.63 W m-2) were compared with those grown without UV-B radiation, and after 12 d one-half of the plants were subjected to 24 d of drought that resulted in mild water stress. UV-B radiation resulted in a decrease of adaxial stomatal conductance by approximately 65%, increasing stomatal limitation of CO2 uptake by 10 to 15%. However, there was no loss of mesophyll light-saturated photosynthetic activity. Growth in UV-B radiation resulted in large reductions of leaf area and plant biomass, which were associated with a decline in leaf cell numbers and cell division. UV-B radiation also inhibited epidermal cell expansion of the exposed surface of leaves. There was an interaction between UV-B radiation and drought treatments: UV-B radiation both delayed and reduced the severity of drought stress through reductions in plant water-loss rates, stomatal conductance, and leaf area. PMID:9576786

  10. WATER CONSTRAINTS IN POWER-PLANT SITING AND OPERATION: WISCONSIN POWER PLANT IMPACT STUDY

    EPA Science Inventory

    A conceptual study of water quality in the Wisconsin River between Wisconsin Dells and Lake Wisconsin was performed to determine the range of choices that might be available for determining the trade-off between organic waste discharges and heat assimilation from possible power p...

  11. Yield and water use of Siberian wildrye with ridge and furrow planting in northern China

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ridge and furrow planting (RFP) is an in-situ rainwater harvesting system that improves yield and water use efficiency (WUE) of alfalfa (Medicago sativa L.) and other crops. However, insufficient and erratic precipitation limit yield in semiarid northern China. We studied the effects of RFP under no...

  12. Soil-moisture limits on plant uptake: An upscaled relationship for water-limited ecosystems

    E-print Network

    Guswa, Andrew J.

    February 2005 Abstract Transpiration in water-limited ecosystems is controlled by the availability of soil are scaled up. This work proposes a simple multi-valued relationship between plant transpiration and average of daily transpiration from an upscaled model that uses this relationship match closely those from

  13. Selenium in water, sediment, plants, invertebrates, and fish in the Blackfoot River drainage

    USGS Publications Warehouse

    Hamilton, S.J.; Buhl, K.J.

    2004-01-01

    Nine stream sites in the Blackfoot River watershed in southeastern Idaho were sampled in September 2000 for water, surficial sediment, aquatic plants, aquatic invertebrates, and fish. Selenium was measured in these aquatic ecosystem components, and a hazard assessment was performed on the data. Water quality characteristics such as pH, hardness, and specific conductance were relatively uniform among the nine sites examined. Selenium was elevated in water, sediment, aquatic plants, aquatic invertebrates, and fish from several sites suggesting deposition in sediments and food web cycling through plants and invertebrates. Selenium was elevated to concentrations of concern in water at eight sites (>5 ??g/L), sediment at three sites (>2 ??g/g), aquatic plants at four sites (>4 ??g/g), aquatic invertebrates at five sites (>3 ??g/g), and fish at seven sites (>4 ??g/g in whole body). The hazard assessment of selenium in the aquatic environment suggested low hazard at Sheep Creek, moderate hazard at Trail Creek, upper Slug Creek, lower Slug Creek, and lower Blackfoot River, and high hazard at Angus Creek, upper East Mill Creek, lower East Mill Creek, and Dry Valley Creek. The results of this study are consistent with results of a previous investigation and indicate that selenium concentrations from the phosphate mining area of southeastern Idaho were sufficiently elevated in several ecosystem components to cause adverse effects to aquatic resources in the Blackfoot River watershed. ?? 2004 Kluwer Academic Publishers.

  14. ARSENIC REMOVAL FROM DRINKING WATER BY ION EXCHANGE AND ACTIVATED ALUMINA PLANTS

    EPA Science Inventory

    This report documents a long term performance study of two ion exchange (IE) and two activated alumina (AA) treatment plants to remove arsenic from drinking water. Performance information was collected on these systems that are located in the northeast for one full year. The stud...

  15. Improvement of PNPI experimental industrial plant based on CECE process for heavy water detritiation

    SciTech Connect

    Bondarenko, S. D.; Alekseev, I. A.; Fedorchenko, O. A.; Vasyanina, T. V.; Konoplev, K. A.; Arkhipov, E. A.; Uborsky, V. V.

    2008-07-15

    An updated experimental industrial plant of PNPI for the development of CECE technology is described. Experimental results for heavy water detritiation in different operating modes are shown. The effect of pressure, temperatures and gas flow rate on the detritiation factor for the CECE process is presented. (authors)

  16. A DEMONSTRATION OF BENEFICIAL USES OF WARM WATER FROM CONDENSERS OF ELECTRIC GENERATING PLANTS

    EPA Science Inventory

    The report gives results of a project to demonstrate that warmed cooling water from condensers of electric generating plants can effectively and economically heat greenhouses. The 0.2-hectare demonstration greenhouse, at Northern States Power Co.'s Sherburne County (Sherco) Gener...

  17. Implications of elevated atmospheric CO2 on plant growth and water relations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Empirical records provide incontestable evidence for the global rise in CO2 concentration in the earth’s atmosphere. Plant growth can be stimulated by elevation of CO2; photosynthesis increases and economic yield is often enhanced. The application of more CO2 can result in less water use. Competitio...

  18. Removal of two antibacterial compounds triclocarban and triclosan in a waste water treatment plant

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study investigates the fate of Triclocarban (TCC) and Triclosan (TCS) in a waste water treatment plant (WWTP). Our goal was to identify the most effective removal step and to determine the amount on the solid phase versus degraded. Our influent contained higher TCS than TCC concentrations (8....

  19. From air to land: understanding water resources through plant-based multidisciplinary research.

    PubMed

    Silva, Lucas C R

    2015-07-01

    Current global challenges require solutions that cannot be delivered by any one field alone. New developments in the analysis and interpretation of plant-derived climatic records bridge traditional disciplines, advancing understanding of phenomena of great ecological and societal significance, specifically, those related to changes in the terrestrial water cycle. PMID:26152736

  20. Water Requirements of Young Blueberry Plants Irrigated by Sprinklers, Microsprays, and Drip

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A study was done to determine the effects of irrigation method on water use by young northern highbush blueberry (Vaccinium corymbosum L. 'Elliott'). Plants were irrigated by overhead sprinkler, microspray, or drip at 50, 100, and 150% of the estimated crop evapotranspiration (ETc) requirement. Du...

  1. WET/DRY COOLING SYSTEMS FOR FOSSIL-FUELED POWER PLANTS: WATER CONSERVATION AND PLUME ABATEMENT

    EPA Science Inventory

    The report gives results of a study of technical and economic feasibilities of wet/dry cooling towers for water conservation and vapor plume abatement. Results of cost optimizations of wet/dry cooling for 1000-MWe fossil-fueled power plants are presented. Five sites in the wester...

  2. High-density grass carp stocking effects on a reservoir invasive plant and water quality

    USGS Publications Warehouse

    Garner, A. Brad; Kwak, Thomas J.; Manuel, Kenneth L.; Barwick, D. Hugh

    2013-01-01

    Stocking grass carp [Ctenopharyngodon idella (Valenciennes)] is a commonly applied technique to control nuisance aquatic vegetation in reservoirs. Factors that influence the degree of aquatic vegetation control are fish stocking density, regional climate, abundance and species composition of the aquatic plant community, and relative grass carp feeding preferences for plant species. We evaluated high-density grass carp stocking in a southeastern U.S. reservoir for control of parrot-feather [Myriophyllum aquaticum (Vell) Verdc.], an invasive aquatic plant that is not preferentially consumed by grass carp and the associated effects on water quality. Lookout Shoals Lake, a 528-ha piedmont North Carolina reservoir, was stocked with triploid grass carp at a density of 100 fish per vegetated hectare. Parrot-feather biomass in the lake was significantly reduced three months after grass carp stocking, compared to biomass in in-situ exclosures. During the second year after grass carp stocking, parrot-feather biomass in the lake compared to biomass in in-situ exclosures indicated continued control, but unexplained lack of growth within most experimental exclosures precluded biomass analyses. Increases in ambient water chlorophyll a, reactive phosphorus, and nitrate-nitrite concentrations were measured after grass carp stocking. The biological significance of observed changes in water chemistry and long-term effects on lake biota remain undetermined. Our results demonstrate that intensive grass carp stocking can control an invasive aquatic plant that is not preferentially consumed by grass carp and reveal associated changes in water quality.

  3. Evaluating Energy and Water Saving Opportunities in SAGD Oil Sands Plants via Process Integration

    E-print Network

    Ahrendt, Wolfgang

    Evaluating Energy and Water Saving Opportunities in SAGD Oil Sands Plants via Process Integration to situations where the savings are limited or where a reduction on a performance metric (e.g., energy savings [4]. [1] http://www.energy.alberta.ca/org/pdfs/Alberta_Energy_Overview.pdf [2]http

  4. PLANT INOCULATION WITH OBLIGATE ENDOPHYTES FROM ARID RANGELAND GRASSES: IMPLICATIONS FOR WATER USAGE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Endophytic inoculation of grasses can result in significant agronomic advantages including increased drought tolerance and disease resistance as well as enhanced water and nutrient uptake. While some endophytes can increase plant toxicity, others are thought to be strictly beneficial. New attempts...

  5. Role of soil adsorption and microbial degradation on dissipation of mesotrione in plant available soil water

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mesotrione is a carotenoid biosynthesis-inhibiting herbicide labeled for pre-emergence and post emergent weed control in corn production. Understanding the factors that influence the dissipation of mesotrione in soil and in the plant available water (PAW) is important for both the environmental fat...

  6. Characterization of light gluten and light steep water from a corn wet milling plant

    E-print Network

    Characterization of light gluten and light steep water from a corn wet milling plant K.D. Rausch March 2003; accepted 10 March 2003 Abstract The primary commodity of corn wet milling is starch, but two coproducts (corn gluten feed, CGF and corn gluten meal, CGM) also are produced. CGM and CGF are marketed

  7. LETTER The incidence and implications of clouds for cloud forest plant water relations

    E-print Network

    Goldsmith, Greg

    satellite and ground-based observa- tions to study cloud and leaf wetting patterns in contrasting tropical land and sea sur- face temperatures will affect cloud patterns (Pounds et al. 1999; Still et al. 1999LETTER The incidence and implications of clouds for cloud forest plant water relations Gregory R

  8. Advanced Power Plant Modeling with Applications to an Advanced Boiling Water

    E-print Network

    Mitchell, John E.

    Advanced Power Plant Modeling with Applications to an Advanced Boiling Water Reactor and a Heat heat transfer. 2. the exact solution of differential equations analytically first through heat transfer, the less computing time advan- tage is not gained because of the additional

  9. OIL IN THE OPEN WATER microscopic plants and animals that form the

    E-print Network

    OIL IN THE OPEN WATER microscopic plants and animals that form the basis of the oceanic food web. The eggs and and recreationally important species are at risk, and ocean-going birds. Far beneath the oil does hit land, it can severely impact stands, and sandy beaches. Organisms that use these habitats

  10. SEASONAL SOIL MOISTURE PREDICTION USING A CLIMATE-PLANT-SOIL COUPLED AGROECOSYSTEM WATER MANAGEMENT MODEL

    E-print Network

    Takle, Eugene S.

    3.13 SEASONAL SOIL MOISTURE PREDICTION USING A CLIMATE-PLANT-SOIL COUPLED AGROECOSYSTEM WATER of soil moisture is given at grid resolution that is too coarse to resolve prominent weather systems on a quasi real-time basis, forecasting soil moisture, precipitation, temperature, and other variables

  11. Tracking the diurnal signal of plant water uptake through the hydrologic system

    NASA Astrophysics Data System (ADS)

    Blume, Theresa; Hassler, Sibylle; Heidbüchel, Ingo; Weiler, Markus; Simard, Sonia; Güntner, Andreas; Heinrich, Ingo

    2015-04-01

    Plant water uptake during summer is characterized by strong diurnal fluctuations. As a result a diurnal sink term is imposed on catchment storage, affecting the unsaturated zone, sometimes the saturated zone and even streamflow. Detecting this signal and understanding its propagation through the hydrological system may help to better quantify eco-hydrological connectivity. The extent and strength of the propagation of this signal from plant to soil to ground- and stream water was investigated with a unique setup of 46 field sites in Luxemburg and 15 field sites in Germany. These sites cover a range of geologies, soils, topographies and types of vegetation. Vegetation types include grassland, pine forest (young and old) and different deciduous forest stands. Available data at all sites includes information at high temporal resolution from 3-5 soil moisture profiles, matrix potential, piezometers and sapflow sensors (as proxy for plant water uptake) as well as standard climate data. At sites with access to a stream, discharge or water level is also recorded. Signal strength (amplitude of diurnal fluctuations) can thus be traced through the system and gives an indication of the physical sphere of influence of plant water uptake i.e. the "eco-hydro-connectivity". Temporal dynamics of signal strength furthermore suggest a shifting spatial distribution of root water uptake with time. The analysis of time lags (or phase shifts) between daily fluctuations in temperature, radiation, sapflow, soil water, groundwater and streamflow gives further insights into the processes driving and propagating these signals and inter-site comparison allows for the investigation of local controls.

  12. Knowledge and abilities catalog for nuclear power plant operators: Boiling water reactors, Revision 1

    SciTech Connect

    1995-08-01

    The Knowledge and Abilities Catalog for Nuclear Power Plant Operators: Boiling-Water Reactors (BWRs) (NUREG-1123, Revision 1) provides the basis for the development of content-valid licensing examinations for reactor operators (ROs) and senior reactor operators (SROs). The examinations developed using the BWR Catalog along with the Operator Licensing Examiner Standards (NUREG-1021) and the Examiner`s Handbook for Developing Operator Licensing Written Examinations (NUREG/BR-0122), will cover the topics listed under Title 10, Code of Federal Regulations, Part 55 (10 CFR 55). The BWR Catalog contains approximately 7,000 knowledge and ability (K/A) statements for ROs and SROs at BWRs. The catalog is organized into six major sections: Organization of the Catalog, Generic Knowledge and Ability Statements, Plant Systems grouped by Safety Functions, Emergency and Abnormal Plant Evolutions, Components, and Theory. Revision 1 to the BWR Catalog represents a modification in form and content of the original catalog. The K/As were linked to their applicable 10 CFR 55 item numbers. SRO level K/As were identified by 10 CFR 55.43 item numbers. The plant-wide generic and system generic K/As were combined in one section with approximately one hundred new K/As. Component Cooling Water and Instrument Air Systems were added to the Systems Section. Finally, High Containment Hydrogen Concentration and Plant Fire On Site evolutions added to the Emergency and Abnormal Plant Evolutions section.

  13. The effect of soil hydrology on the oxygen and hydrogen isotopic compositions of plants' source water

    NASA Astrophysics Data System (ADS)

    Tang, Kuilian; Feng, Xiahong

    2001-02-01

    Many studies have demonstrated that the isotopic composition of plants' source water is the main factor affecting the isotopic composition of tree rings. Because of soil hydrological processes, soil water as the source water for plants may isotopically differ from precipitation that contains climatic information (such as surface temperature). This study addresses the effects of soil hydrological processes on the isotopic compositions of soil water and discusses how these effects affect interpretations of tree ring data in isotopic dendroclimatology. We collected precipitation, soil gas at two depths (20 and 50 cm), and twigs from a maple tree ( Acer saccharum) on a biweekly basis during the growing season in 1997-1999 at Hanover, NH, USA. Water was extracted from the twig samples by vacuum distillation. All water samples were analyzed for both ?D and ? 18O. Soil CO 2 was extracted from soil gas and measured for the ? 18O values, and using the soil temperature and assuming isotopic equilibrium between CO 2 and H 2O, we calculated the ? 18O values of soil water. Comparisons among the isotopic time series of each type of sample indicate the following. (1) The isotopic composition of soil water is much less variable than that of precipitation, suggesting isotopic mixing between waters of different precipitation events. (2) In early spring, soil water at all depths is isotopically similar to winter precipitation, but with time the surface soil water becomes progressively enriched in deuterium and 18O due to infiltration of summer rain and enrichment through soil water evaporation. (3) The influence of summer precipitation decreases with increasing depth, and soil at 50 cm can only receive water from large storms. (4) Replacement of old soil water with new infiltrating water is dependent upon frequency and intensity of growing season precipitation, and it is generally more efficient in a wet year than in a dry year. (5) The tree we studied uses water mainly from near-surface soil layers. (6) The ?D-? 18O relationship in twig water indicates that soil water has experienced isotopic enrichment by evaporation. These results have important implications for selecting sites for paleoclimatic studies using isotopic data of tree rings.

  14. Control of water and nutrients using a porous tube - A method for growing plants in space

    NASA Technical Reports Server (NTRS)

    Dreschel, Thomas W.; Sager, John C.

    1989-01-01

    A plant nutrient delivery system that uses a microporous, hydrophilic tube was developed with potential application for crop production in the microgravity of space. The tube contains a nutrient solution and delivers it to the roots. Pumps attached to the tubing create a very small suction that holds the solution within the tube. This system was used to grow wheat for 107 d in a controlled environment at suctions of 0.40, 1.48, or 2.58 kPa. The water absorbed through the pores of the tube by baby diaper sections decreased as suction increased. Correspondingly, final plant biomass, seed number, and spikelet number also tended to decrease as suction increased. The reduced yield at higher suction suggests that the plants experienced water stress, although all suctions were below those typical of soils at field capacity.

  15. Water uptake by plant roots — A simulation model, I. Conceptual model

    NASA Astrophysics Data System (ADS)

    Perrochet, P.

    1987-11-01

    A new attempt to define the volumetric sink term added to the continuity equation for soil-water flow and describing plant water uptake by roots is proposed here. This sink function allows the introduction of plant parameters and the calculation of the actual transpiration rate as a function of time given a pedologic, climatic and cultural situation. This new definition considers physical principles that let us describe a given soil-plant system with more parameters. Apart from the analysis of irrigation problems and devices for which this model is designed, one can easily use it to approach other problems related to the unsaturated zone like natural or artificial recharge of the groundwater table and its relations with the vegetation.

  16. Unit III-3 -Singular value decomposition 1 Singular value decomposition

    E-print Network

    Birkett, Stephen

    Unit III-3 - Singular value decomposition 1 Unit III-3 Singular value decomposition Unit III-3 - Singular value decomposition 2 Eigenvalue decomposition re-visited · for a square matrix A the eigenvalue decomposition (EVD) can be written AU = DU ..... · ..... but only for some matrices as A = UDU-1 · what about

  17. Drip irrigation management in different chufa planting strategies: yield and irrigation water use efficiency

    NASA Astrophysics Data System (ADS)

    Pascual-Seva, Nuria; San Bautista, Alberto; López-Galarza, Salvador; Maroto, José Vicente; Pascual, Bernardo

    2013-04-01

    In a study presented in the EGU assembly 2012, it was analysed how yield and irrigation water use efficiency (IWUE) in chufa (Cyperus esculentus L. var. sativus), crop, were affected by planting strategy (ridges and flat raised beds, with two and three plant rows along them) and irrigation system [furrow (FI) and drip irrigation (DI)]. Each irrigation session started when the Volumetric Soil Water Content (VSWC) in ridges dropped to 80% of field capacity; beds were irrigated simultaneously with ridges and with the same irrigation duration. R produced lower yield than the two types of beds, and yields in DI were higher than those FI. Ridges led to the highest IWUE with DI, and to the lowest with FI. Then, it was decided to analyse, in DI, how yield and IWUE responded to start each irrigation session when the VSWC in the central point of different planting strategies [ridges (R), and flat raised beds with two (b) and three (B) plant rows along them] dropped to 80% of field capacity. In R and b, plants were irrigated by a single dripline per plant row, while in B two irrigation layouts were assayed: a single dripline per plant row (B3) and two driplines per bed (B2), placing each dripline between two planting rows. Irrigation session stop was also automated as a function of the VSWC. Results show that yield was affected (P˜0.01) by planting strategy; the greatest yield was obtained in b (2.4 kgm-2), differing (P˜0.05) from that obtained in R (2.1 kgm-2), with intermediate yields in B2 (2.3 kgm-2) and B3 (2.3 kgm-2). Yield was not affected (P˜0.05) by the utilisation of two or three driplines in B. Considerably less irrigation water was applied (IWA) in R (376 mm) than in B3 (465 mm), B2 (475 mm) and b (502 mm). This automatic irrigation management, as a function of the VSWC in each planting strategy, lead to adjust the IWA to the plant water requirements, which were similar in all three flat raised beds, since they correspond to the same planting density, that was, in turn, higher than in R. IWUE was affected (P˜0.01) by the planting strategy, obtaining greater (P˜0.05) values in R (5.54 kgm-3) than in B3 (4.84 kgm-3), B2 (4.76 kgm-3), and b (4.73 kgm-3). With the herein presented irrigation management, IWUE in flat raised beds considerably increased in relation to the previous experiments (automated as a function of the VSWC in R), although they resulted in lower values (P˜0.05) than in R. When comparing the different planting rows, neither the yield nor the average tuber weight was affected by their position. b leaded to the highest yield, while R resulted in the lowest yield, but with the highest IWUE. Considering the current prices of both tubers and irrigation water, the profit obtained by the increase in yield reached with b is greater than the cost that supposes its greater IWA. Nevertheless, if there were water delivery restrictions or price increases, R would represent a recommendable strategy.

  18. Neutron radiography and modelling of water flow and D2O transport in soil and plants

    NASA Astrophysics Data System (ADS)

    Zare, Mohsen; Carminati, Andrea; Kröner, Eva

    2014-05-01

    Our understanding of soil and plant water relations is currently limited by the lack of experimental methods to measure the water fluxes in soil and plants. Our study aimed to develop a new non-destructive method to measure the local fluxes of water into roots of plants growing in soil. We injected deuterated water (D2O) near the roots of lupines growing in sandy soils, and we used neutron radiography to image the transport of D2O through the root system. The experiments were performed during day, when plants were transpiring, and at night, when transpiration was reduced. The radiographs showed that: 1) the radial transport of D2O from soil and roots depended similarly from diffusion and convection; and 2) the axial transport of D2O along the root xylem was largely dominated by convection. To determine the convective fluxes from the radiographs, we simulated the D2O transport in soils and roots. A dual porosity model was used to describe the apoplastic and symplastic pathways of water across the root tissue. Other features as the endodermis and the xylem were also included in the model. The D2O transport was modelled solving a convection-diffusion numerical model in soil and plants. The diffusion coefficients of the root tissues were inversely estimated by simulating the experiments at night under the assumption that at night the convective fluxes were negligible. Inverse modelling of the experiment at day gave the profile of water fluxes into the roots, as well as the ration between the apoplastic and symplastic flow. For 24 day-old lupine grown in a sandy soil with uniform water content, our modelling results showed that root water uptake was higher at the proximal parts of the roots near soil surface and it decreased toward the distal parts. The results indicated the water crossed the root cortex mainly through the apoplastic pathway. The method allows the quantification of the root properties and the regions of root water uptake along root systems growing in soils.

  19. [Effects of waste water sediments on the levels of heavy metals ion the soil and plants].

    PubMed

    Siniagina, N A; Sul'din, B V; Tumanov, A N; Chetvergov, E V

    2004-01-01

    Field small-plot experiments studied the effects of sediments of waste water from Saransk disposal systems. The content of toxic heavy metals (lead, arsenic, and cadmium) in the waste-water sediments, was shown to be not greater than their maximum permissible concentrations (32, 2, and 10 mg per kg of dried soil, respectively). With the use of waste-water sediments, the content of manganese, copper, tin, nickel, vanadium, beryllium, cobalt, iron, and chromium was found to correspond to their baseline level in the soil and plants. PMID:15141618

  20. Modeling of underground thermal behavior of solar hot water during treatment of harmful plants

    SciTech Connect

    Eltez, M.

    1998-04-01

    Annihilation of harmful plants among vegetables by solar hot-water injection into the roots is an alternative to chemical treatment methods. A three-dimensional solution of the heat diffusion equation between the treated region and the vegetable root is presented with related boundary conditions. Soil properties and dimensional characteristics are important for obtaining safety limitations of the treatment. A mathematical model with suitable outputs gives practical results for correct application of solar hot water. Critical distances between overheating of vegetable roots and useful irrigation water effects are distinguished.