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1

[Effects of aquatic plants during their decay and decomposition on water quality].  

PubMed

Taking 6 aquatic plant species as test objects, a 64-day decomposition experiment was conducted to study the temporal variation patterns of nutrient concentration in water body during the process of the aquatic plant decomposition. There existed greater differences in the decomposition rates between the 6 species. Floating-leaved plants had the highest decomposition rate, followed by submerged plants, and emerged plants. The effects of the aquatic plant species during their decomposition on water quality differed, which was related to the plant biomass density. During the decomposition of Phragmites australis, water body had the lowest concentrations of chemical oxygen demand, total nitrogen, and total phosphorus. In the late decomposition period of Zizania latifolia, the concentrations of water body chemical oxygen demand and total nitrogen increased, resulting in the deterioration of water quality. In the decomposition processes of Nymphoides peltatum and Nelumbo nucifera, the concentrations of water body chemical oxygen demand and total nitrogen were higher than those during the decomposition of other test plants. In contrast, during the decomposition of Potamogeton crispus and Myriophyllum verticillatum, water body had the highest concentrations of ammonium, nitrate, and total phosphorus. For a given plant species, the main water quality indices had the similar variation trends under different biomass densities. It was suggested that the existence of moderate plant residues could effectively promote the nitrogen and phosphorus cycles in water body, reduce its nitrate concentration to some extent, and decrease the water body nitrogen load. PMID:23717994

Tang, Jin-Yan; Cao, Pei-Pei; Xu, Chi; Liu, Mao-Song

2013-01-01

2

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...

3

Fast Construction of Plant Architectural Models Based on Substructure Decomposition  

Microsoft Academic Search

Plant structure, representing the physical link among different organs, includes many similar substructures. In this paper, a new method is presented to construct plant architectural models of most plant species. The plant structure is decomposed into a stem, a set of lateral substructures and a terminal substructure, which is called substructure decomposition; then based on substructure decomposition, the plant structures

Hongping Yan; Philippe De Reffye; Chunhong Pan; Bao-gang Hu

2003-01-01

4

Proximate nutritive value changes during decomposition of salt marsh plants  

Microsoft Academic Search

Recognition of salt marsh plant detritus as a nutritious source of food for estuarine consumers prompted investigation of in situ decomposition and proximate nutritive values of three plants and their detritus namely: Spartina cynosuroides and Distichlis spicata (Gramineae) and Scirpus americanus (Cyperaceae) growing abundantly in Mississippi tidal marshes. During decomposition to particulate detritus, these plants retain 60–70% organic content and

Armando A. Cruz

1975-01-01

5

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

PubMed

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

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

6

Decomposition dynamic of higher plant pigments by HPLC analysis.  

PubMed

The fate of the litter of dominant vegetation(willows and reeds) is one of the aspects studied in the frame of the project "Onderzoek Milieu Effecten Sigmaplan". One of the questions to be considered is how long the litter stays within the estuary. In this paper, the time the leaf litter (Salix triandra and Phragmites australis) stayed in the Schelde estuary was studied by using plant pigment as biomarkers with HPLC application. After analyzing the original data from the incubation experiment described by Dubuison and Geers (1999), the decomposition dynamics patterns of pigments were analyzed and described, and these decomposition dynamics patterns were used as calibration patterns. By using Spearman Rank Order Correlation, the calibration patterns of the pigments which were significant (p < 0.05) were grouped. In this way, several groups of the calibration patterns of pigment decomposition were achieved. The presence or absence of these groups of pigments (whether they can be detected or not from HPLC) was shown to be useful in determining the time the litter has stayed in the water. Combining data of DW and POC, more precise timing can be obtained. PMID:15559826

Luo, Yi; Zhang, Ting-Zhou; Zhou, Qi-Xing; Mao, Da-Qing; Wan, Dong-Mei

2004-01-01

7

Highly consistent effects of plant litter identity and functional traits on decomposition across a latitudinal gradient.  

PubMed

Plant litter decomposition is a key process in terrestrial carbon cycling, yet the relative importance of various control factors remains ambiguous at a global scale. A full reciprocal litter transplant study with 16 litter species that varied widely in traits and originated from four forest sites covering a large latitudinal gradient (subarctic to tropics) showed a consistent interspecific ranking of decomposition rates. At a global scale, variation in decomposition was driven by a small subset of litter traits (water saturation capacity and concentrations of magnesium and condensed tannins). These consistent findings, that were largely independent of the varying local decomposer communities, suggest that decomposer communities show little specialisation and high metabolic flexibility in processing plant litter, irrespective of litter origin. Our results provide strong support for using trait-based approaches in modelling the global decomposition component of biosphere-atmosphere carbon fluxes. PMID:22732002

Makkonen, Marika; Berg, Matty P; Handa, I Tanya; Hättenschwiler, Stephan; van Ruijven, Jasper; van Bodegom, Peter M; Aerts, Rien

2012-06-26

8

Algebraic Decomposition of Fat and Water in MRI  

Microsoft Academic Search

The decomposition of MRI data to generate water and fat images has several applications in medical imaging, including fat suppression and quantification of visceral fat. We introduce a novel algorithm to overcome some of the problems associated with current analytical and iterative decomposition schemes. In contrast to traditional analytical schemes, our approach is general enough to accommodate any uniform echo-

Mathews Jacob; Bradley P. Sutton

2009-01-01

9

Plant Water Relations  

NSDL National Science Digital Library

Plant water relations are presented in this learning activity to help participants understand the components of water potential, explain how water moves through plants, provide examples of plant adaptations to water stress, and have a general understanding of how water potential can be measured.

Bidlack, Jim

10

Elevated atmospheric carbon dioxide effects on cotton plant residue decomposition  

Microsoft Academic Search

Assessing the impact of elevated atmospheric COâ concentration on the global environment is hampered due to a lack of understanding of global C cycling. Carbon fixed within plant biomass ultimately enters the soil via plant residues, but the effects of elevated-COâ-grown plant material on decomposition rates and long-term soil C storage are unknown. The objective of this study was to

H. A. Torbert; S. A. Prior; H. H. Rogers

1995-01-01

11

Fear of predation slows plant-litter decomposition.  

PubMed

Aboveground consumers are believed to affect ecosystem functioning by regulating the quantity and quality of plant litter entering the soil. We uncovered a pathway whereby terrestrial predators regulate ecosystem processes via indirect control over soil community function. Grasshopper herbivores stressed by spider predators have a higher body carbon-to-nitrogen ratio than do grasshoppers raised without spiders. This change in elemental content does not slow grasshopper decomposition but perturbs belowground community function, decelerating the subsequent decomposition of plant litter. This legacy effect of predation on soil community function appears to be regulated by the amount of herbivore protein entering the soil. PMID:22700928

Hawlena, Dror; Strickland, Michael S; Bradford, Mark A; Schmitz, Oswald J

2012-06-15

12

MASCOT - A bench-scale plant for producing hydrogen by the UT3 thermochemical decomposition cycle  

Microsoft Academic Search

A bench-scale plant for producing hydrogen has been constructed on the basis of the thermochemical water-decomposition process, UT-3, consisting of Br, Ca and Fe compounds. This plant is named MASCOT (Model Apparatus for Studying Cyclic Operation in Tokyo) and is designed to be capable of producing 3 1\\/h of gaseous hydrogen at standard conditions. During several test runs, the continuous

T. Nakayama; H. Yoshioka; H. Furutani; H. Kameyama; K. Yoshida

1984-01-01

13

Dynamics of alpine plant litter decomposition in a changing climate  

Microsoft Academic Search

Climatic changes resulting from anthropogenic activities over the passed century are repeatedly reported to alter the functioning\\u000a of pristine ecosystems worldwide, and especially those in cold biomes. Available literature on the process of plant leaf litter\\u000a decomposition in the temperate Alpine zone is reviewed here, with emphasis on both direct and indirect effects of climate\\u000a change phenomena on rates of

Konstantin S. Gavazov

2010-01-01

14

Plant decomposition and soil respiration in terrestrial ecosystems  

Microsoft Academic Search

Summary  This review deals with methodological approaches, measured rates, and environmental control of two major interdependent processes\\u000a regulating the structure and function of terrestrial ecosystems, viz., plant decomposition and soil respiration.\\u000a \\u000a Both these processes have been evaluated through indirect assessments as well as through direct measurements under the field\\u000a conditions. The techniques used suffer in general from difficulties in creating conditions

J. S. Singh; S. R. Gupta

1977-01-01

15

Metal-induced decomposition of perchlorate in pressurized hot water.  

PubMed

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

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

2012-07-27

16

Adiabatic calorimetric decomposition studies of 50 wt.% hydroxylamine\\/water  

Microsoft Academic Search

Calorimetric data can provide a basis for determining potential hazards in reactions, storage, and transportation of process chemicals. This work provides calorimetric data for the thermal decomposition behavior in air of 50wt.% hydroxylamine\\/water (HA), both with and without added stabilizers, which was measured in closed cells with an automatic pressure tracking adiabatic calorimeter (APTAC). Among the data provided are onset

Lizbeth O Cisneros; William J Rogers; M. Sam Mannan

2001-01-01

17

Water Desalination Plant  

NSDL National Science Digital Library

Students use a thermal process approach to design, build and test a small-scale desalination plant that is capable of significantly removing the salt content from a saltwater solution. Students use a saltwater circuit to test the efficiency of their model desalination plant and learn how the water cycle is the basis for the thermal processes that drive their desalination plant.

Integrated Teaching And Learning Program

18

Heterogeneous Sensitized Decomposition of Water with Sunlight.  

National Technical Information Service (NTIS)

The goal of the program is to demonstrate that an inexpensive heterogeneous photocatalyst may efficiently decompose water to hydrogen and oxygen (or H2O2) with sunlight. The research is specifically focused on sensitization of known photocatalysts to the ...

A. K. Ghosh H. P. Maruska

1976-01-01

19

Heterogeneous Sensitized Decomposition of Water with Sunlight.  

National Technical Information Service (NTIS)

The goal of the program is to demonstrate that an inexpensive heterogeneous photocatalyst may efficiently decompose water to hydrogen and oxygen (or H2O2) with sunlight. The research is specifically focused on sensitization of known photocatalysts to the ...

A. K. Ghosh H. P. Maruska

1975-01-01

20

Heterogeneous Sensitized Decomposition of Water with Sunlight.  

National Technical Information Service (NTIS)

Studies of the sensitization of TiO2 electrodes to visible light to achieve the photoelectrolysis of water with sunlight have been undertaken. Sensitization has been accomplished by: (1) impurity doping; (2) dye sensitization; and (3) heterojunction forma...

A. K. Ghosh H. P. Maruska

1976-01-01

21

Kinetics of the pyrolytic and hydrothermal decomposition of water hyacinth.  

PubMed

The kinetics of water hyacinth decomposition using pyrolysis and hydrothermal treatment was compared. With pyrolysis, initial vaporization occurred at 453 K as determined by thermogravimetric analysis, while initial solubilisation occurred at 433 K with subcritical hydrothermal treatment. The "kinetic triplet" was determined for the ranges of 423-483 K (range I) and 473-553 K (range II) using the Coats-Redfern method for both treatments. The calculated activation energies for ranges I and II were 110 and 116 kJ/mol for conventional pyrolysis and 145 and 90 kJ/mol for hydrothermal treatment. The similar activation energies for the two temperature ranges observed for pyrolysis implied that only hemicellulose decomposition occurred. For hydrothermal treatment, both hemicellulose and cellulose decomposition occurred in temperature range II, in which a notable lower activation energy was observed. This implied hydrothermal treatment was more suitable for conversion lignocellulosic biomass under these conditions. PMID:21558054

Luo, Guang'en; Strong, P James; Wang, Hailong; Ni, Wuzhong; Shi, Weiyong

2011-04-21

22

Decomposition and Terapascal Phases of Water Ice  

NASA Astrophysics Data System (ADS)

Computational searches for stable and metastable structures of water ice and other H:O compositions at TPa pressures have led us to predict that H2O decomposes into H2O2 and a hydrogen-rich phase at pressures of a little over 5 TPa. The hydrogen-rich phase is stable over a wide range of hydrogen contents, and it might play a role in the erosion of the icy component of the cores of gas giants as H2O comes into contact with hydrogen. Metallization of H2O is predicted at a higher pressure of just over 6 TPa, and therefore H2O does not have a thermodynamically stable low-temperature metallic form. We have also found a new and rich mineralogy of complicated water ice phases that are more stable in the pressure range 0.8-2 TPa than any predicted previously.

Pickard, Chris J.; Martinez-Canales, Miguel; Needs, Richard J.

2013-06-01

23

Water vapor decomposition reaction on ZrNi alloy  

Microsoft Academic Search

To develop a method for decomposing hydrogen compounds and for extracting hydrogen in only the chemical form of hydrogen molecules, a zirconium nickel (ZrNi) alloy was used to decompose water vapor. Inspection of alloy samples using X-ray diffraction spectra taken before use, midway through decomposition, and after use revealed that the ZrNi was gradually consumed and that ZrO2 and pure

Takao Kawano

2006-01-01

24

Plant Water Relations.  

ERIC Educational Resources Information Center

|Some simple field investigations on plant water relations are described which demonstrate links between physiological and external environmental factors. In this way, a more complex picture of a plant and how it functions within its habitat and the effects the environment has on it can be built up. (Author/JN)|

Tomley, David

1982-01-01

25

Adiabatic calorimetric decomposition studies of 50 wt.% hydroxylamine/water.  

PubMed

Calorimetric data can provide a basis for determining potential hazards in reactions, storage, and transportation of process chemicals. This work provides calorimetric data for the thermal decomposition behavior in air of 50wt.% hydroxylamine/water (HA), both with and without added stabilizers, which was measured in closed cells with an automatic pressure tracking adiabatic calorimeter (APTAC). Among the data provided are onset temperatures, reaction order, activation energies, pressures of noncondensable products, thermal stability at 100 degrees C, and the effect of HA storage time. Discussed also are the catalytic effects of carbon steel, stainless steel, stainless steel with silica coating, inconel, titanium, and titanium with silica coating on the reaction self-heat rates and onset temperatures. In borosilicate glass cells, HA was relatively stable at temperatures up to 133 degrees C, where the HA decomposition self-heat rate reached 0.05 degrees C/min. The added stabilizers appeared to reduce HA decomposition rates in glass cells and at ambient temperatures. The tested metals and metal surfaces coated with silica acted as catalysts to lower the onset temperatures and increase the self-heat rates. PMID:11165058

Cisneros, L O; Rogers, W J; Mannan, M S

2001-03-19

26

Decomposition of Volatile Organic Compounds and Environmental Hazardous Substances in Water using Discharge Plasma  

NASA Astrophysics Data System (ADS)

Recent works for the decomposition of gaseous volatile organic compounds (VOCs) and environmental hazardous substances in water using discharge plasma are encapsulated. The kinds of reactors used for the decomposition of VOCs, the decomposition characteristics of VOCs by the reactors and the effects of the discharge type, applied voltage, etc. on VOCs decomposition are briefly described. Further, the detailed investigation of by-products from benzene, toluene and xylene and the estimation of decomposition path of acetone by discharge plasma treatment are introduced as works which contribute to the design of VOC-decomposition reactors and to assuring the safety of VOCs decomposition by the discharge plasma. For the decomposition of environmental hazardous substances in water by discharge plasma, the treatment of aqueous phenol solution and organic dyes are focused. The effects of sparging gas, the conductivity of the solution, background-gas composition, etc. on phenol decomposition rate are described, and the mechanism that the species contributing phenol decomposition change with the background-gas composition is illustrated in detail. Recent works to clarify the by-products of phenol are also introduced. For the decomposition rate of organic dyes, the effects of pH of solution, background-gas composition, etc. on the decomposition rate and the species contributing the decomposition are shown. Further, the efficiency difference for organic-dye decomposition due to the kinds of discharge plasma reactor is introduced.

Satoh, Kohki

27

Stoichiometry of Microbial Decomposition Priming in Plant Litter and Soil  

NASA Astrophysics Data System (ADS)

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. .

Schaefer, D.; Qiao, N.

2011-12-01

28

Continuous and selective determination of water vapor evolved during thermal decomposition reactions  

Microsoft Academic Search

A method suitable for the continuous and selective determination of water vapor evolved during thermal decomposition processes is described. The water detector can be connected to thermoanalytical equipment of controlled gas atmosphere without any difficulty. Water vapor, together with other gaseous decomposition products, is collected by the carrier gas and transported through a glass reaction vessel containing the measuring and

J. Kristóf; J. Inczédy; J. Paulik; R Paulik

1991-01-01

29

Elevated CO2 and plant species diversity interact to slow root decomposition  

SciTech Connect

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.

De Graaff, Marie-Anne [ORNL; Schadt, Christopher Warren [ORNL; Rula, Kelly L [ORNL; Six, Johan W U A [University of California, Davis; Schweitzer, Jennifer A [ORNL; Classen, Aimee T [University of Tennessee, Knoxville (UTK)

2011-01-01

30

Early diagenesis of vascular plant tissues: Lignin and cutin decomposition and biogeochemical implications  

Microsoft Academic Search

Long-term subaqueous decomposition patterns of five different vascular plant tissues including mangrove leaves and wood (Avicennia germinans), cypress needles and wood (Taxodium distichum) and smooth cordgrass (Spartina alternifora) were followed for a period of 4.0 years, representing the longest litter bag decomposition study to date. All tissues decomposed under identical conditions and final mass losses were 97, 68, 86, 39,

Stephen Opsahl; Ronald Benner

1995-01-01

31

Plant Hormones and Water Stress  

Microsoft Academic Search

In recent years, the involvement of plant hormones has become a subject of interest in plant water relations. The interest was initially stimulated by research into leaf ageing and plant senescence and the role of cytokinins in these processes. Plant water stress and some other stresses enhance senescence. They also bring about reduction in the levels of endogenous cytokinins. Exogenous

Y. Vaadia

1976-01-01

32

Atmospheric water vapor as driver of litter decomposition during rainless seasons  

NASA Astrophysics Data System (ADS)

Litter production in many drought-affected ecosystems coincides with the beginning of an extended season of no or limited rainfall. Because of lack of moisture litter decomposition during such periods has been largely ignored so far, despite potential importance for the overall decay process in such ecosystems. To determine drivers and extent of litter decay in rainless periods a litterbag study was conducted in Mediterranean shrublands, dwarf shrublands and grasslands. Heterogeneous local and common straw litter was left to decompose in open and shaded patches of various field sites in two study regions. Fresh local litter lost 4-18% of its initial mass over about 4 months without rainfall, which amounted to 15-50% of total annual decomposition. Lab incubations and changes in chemical composition suggested that litter was degraded by microbial activity, enabled by absorption of water vapor from the atmosphere. High mean relative humidity of 85% was measured during 8-9 h of most nights, but the possibility of fog deposition or dew formation at the soil surface was excluded. Over 95% of the variation in mass loss and changes in litter nitrogen were explained by characteristics of water-vapor uptake by litter. Photodegradation induced by the intense solar radiation was an additional mechanism of litter decomposition as indicated by lignin dynamics. Lignin loss from litter increased with exposure to ultraviolet radiation and with initial lignin concentration, together explaining 90-97% of the variation in lignin mass change. Results indicate that water vapor is a driver of litter decay which has been ignored so far. Water-vapor absorption presumably enables microbial degradation, which, together with solar radiation and litter quality, controls decomposition and changes in litter chemistry during rainless seasons. Warmer and drier conditions as a consequence of climate change will result in enhanced drying of litter layers also outside currently classified drylands. In addition, land-use change, e.g. logging, and fire open up plant canopies and significantly enhance dehydration of litter. With a large part of the land area affected by climate change, land-use change and/or fire, drying of litter layers is probably already a common phenomenon and might be more so in the future. Therefore, absorption of water vapor might play a role in decomposition and nutrient cycling in an increasing number of ecosystems.

Dirks, I.; Navon, Y.; Kanas, D.; Dumbur, R.; Grünzweig, José

2010-05-01

33

Influence of non-cellulose structural carbohydrate composition on plant material decomposition in soil  

Microsoft Academic Search

The C mineralisation pattern during the early stage of decomposition of plant materials is largely determined by their content\\u000a of different carbohydrates. This study investigated whether detailed plant analysis could provide a better prediction of C\\u000a mineralisation during decomposition than proximate analysis [neutral detergent solution (NDF)\\/acid detergent solution (ADF)].\\u000a The detailed analysis included sugars, fructans, starch, pectin, cellulose, lignin and

Sophie Gunnarsson; Håkan Marstorp; A Sigrun Dahlin; Ernst Witter

2008-01-01

34

Economic Comparison of Hydrogen Production Using Sulfuric Acid Electrolysis and Sulfur Cycle Water Decomposition. Final Report.  

National Technical Information Service (NTIS)

An evaluation of the relative economics of hydrogen production using two advanced techniques was performed. The hydrogen production systems considered were the Westinghouse Sulfur Cycle Water Decomposition System and a water electrolysis system employing ...

G. H. Farbman B. R. Krasicki C. C. Hardman S. S. Lin G. H. Parker

1978-01-01

35

[Characteristics of the biochemical composition of plant litter at different stages of decomposition (according to thermal analysis data)].  

PubMed

The composition of samples of needles, leaves, sheaved cottongrass (Eriophorum vaginatum) tissues, and the L horizon of the forest floor of different degree of decomposition, isolated from the plant litter in southern taiga ecosystems, was studied by thermal analysis. It was established that plant litter decomposition is accompanied by structural changes in celluloses and that the decomposition rates of hemicellulose and structured cellulose vary at different stages of decomposition. The structural specificity and incongruent thermal decomposition of grass lignocellulose were observed in all samples of plant material. The rates at which the content of components of the plant litter decreased depended on the type and stage of decomposition of plant material. The decomposition rate of biochemical components tended to increase in better drained soils. PMID:18491564

Kosheleva, Iu P; Trofimov, S Ia

36

Researching power plant water recovery  

SciTech Connect

A range of projects supported by NETl under the Innovations for Existing Plant Program are investigating modifications to power plant cooling systems for reducing water loss, and recovering water from the flue gas and the cooling tower. This paper discusses two technologies showing particular promise condense water that is typically lost to evaporation, SPX technologies' Air2Air{sup trademark} condenses water from a cooling tower, while Lehigh University's process condenses water and acid in flue gas. 3 figs.

NONE

2008-04-01

37

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

SciTech Connect

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.

De Graaff, Marie-Anne [ORNL; Classen, Aimee T [University of Tennessee, Knoxville (UTK); Castro Gonzalez, Hector F [ORNL; Schadt, Christopher Warren [ORNL

2010-01-01

38

Soil animals alter plant litter diversity effects on decomposition.  

PubMed

Most of the terrestrial net primary production enters the decomposer system as dead organic matter, and the subsequent recycling of C and nutrients are key processes for the functioning of ecosystems and the delivery of ecosystem goods and services. Although climatic and substrate quality controls are reasonably well understood, the functional role of biodiversity for biogeochemical cycles remains elusive. Here we ask how altering litter species diversity affects species-specific decomposition rates and whether large litter-feeding soil animals control the litter diversity-function relationship in a temperate forest ecosystem. We found that decomposition of a given litter species changed greatly in the presence of litters from other cooccurring species despite unaltered climatic conditions and litter chemistry. Most importantly, soil fauna determined the magnitude and direction of litter diversity effects. Our data show that litter species richness and soil fauna interactively determine rates of decomposition in a temperate forest, suggesting a combination of bottom-up and top-down controls of litter diversity effects on ecosystem C and nutrient cycling. These results provide evidence that, in ecosystems supporting a well developed soil macrofauna community, animal activity plays a fundamental role for altered decomposition in response to changing litter diversity, which in turn has important implications for biogeochemical cycles and the long-term functioning of ecosystems with ongoing biodiversity loss. PMID:15671172

Hättenschwiler, Stephan; Gasser, Patrick

2005-01-25

39

Estimation of hydrogen peroxide decomposition rates in the boiling water reactor primary coolant circuit  

SciTech Connect

In a boiling water reactor primary coolant circuit, the coolant flow velocities and volume-to-surface ratios at various locations are taken into account for the estimation of the decomposition rate of hydrogen peroxide in the system. The decomposition half-times are estimated ranging from a few seconds in the core region to a few minutes in the recirculation piping system.

Lin, Chien C. (GE Nuclear Energy, Pleasanton, CA (United States). Vallecitos Nuclear Center.)

1993-08-01

40

Estimation of hydrogen peroxide decomposition rates in the boiling water reactor primary coolant circuit  

Microsoft Academic Search

In a boiling water reactor primary coolant circuit, the coolant flow velocities and volume-to-surface ratios at various locations are taken into account for the estimation of the decomposition rate of hydrogen peroxide in the system. The decomposition half-times are estimated ranging from a few seconds in the core region to a few minutes in the recirculation piping system.

Lin; Chien C

1993-01-01

41

Interactions between decomposition of plant residues and nitrogen cycling in soil  

Microsoft Academic Search

The processes of N mineralization and immobilization which can occur in agricultural soils during decomposition of plant residues are briefly reviewed in this paper. Results from different incubation studies have indicated that the amounts of N immobilized can be very important and that the intensity and kinetics of N immobilization and subsequent remineralization depend on the nature of plant residues

B. Mary; S. Recous; D. Darwis; D. Robin

1996-01-01

42

Enzyme activities during litter decomposition of two exotic and two native plant species in hardwood forests of New Jersey  

Microsoft Academic Search

Invasions by exotic plant species can alter ecosystem properties, including important soil functions and characteristics. As a result, decomposition of litter from the exotic, as well as native plants, can also be altered, leading to more profound changes in ecosystem functioning. We present here a study of eight enzyme activities during the decomposition of litter from four plant species, two

P. S Kourtev; J. G Ehrenfeld; W. Z Huang

2002-01-01

43

Biogeochemistry of Decomposition and Detrital Processing  

Microsoft Academic Search

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

J. Sanderman; R. Amundson

2003-01-01

44

Water Treatment Plant  

NSDL National Science Digital Library

In most parts of the United States, getting clean, safe water is as easy as turning on a faucet. Generally, this water comes from either groundwater or nearby streams and reservoirs. What most of us never see or have to worry about are the steps required to make this water drinkable. This video segment, adapted from a ZOOM television broadcast, shows how a water treatment facility in Cambridge, Massachusetts purifies its city's water. The segment is two minutes twenty seconds in length.

45

A Modal Decomposition of the Rotating Shallow Water Equations  

NASA Astrophysics Data System (ADS)

The dynamics of the atmosphere and oceans are complicated because of the vast range of length and time scales involved. Understanding how energy cascades from the large to small scales is an outstanding problem in the field and of great interest. In any attempt to do this it is always necessary to specify the physical structure of the basis functions. Perhaps the most popular choice are Fourier modes, which are desirable because they 1) can form a complete basis; 2) are well understood because of the richness of Fourier analysis; and 3) are a basis for high-order spectral methods. This is a convenient choice but numerous other possibilities exist, such as polynomials and wavelets. All of these choices are generic in that they do not arise from the underlying physics of the waves and can usually be applied to virtually any problem. The motivation for this work stems from the idea that a better choice for basis functions should be dictated by the model equations. One relatively simple model that has often been used to looked at energy transfers between different length and time scales is the Rotating Shallow Water model (RSW). It is restrictive in that it only describes homogeneous fluids, however, because it can contain both fast gravity and slow Rossby waves it is a useful paradigm to study energy transfers between waves with vastly different scales. The pioneering work of Leith (1980) investigated the decomposition of the RSW into its linear modes and subsequently others have built on this to understand the modal structure of stratified flows. In these works the emphasis has been on f-plane and therefore the slow component was a vortical mode that does not propagate. In his original paper Leith points out that it would be interesting to extend his methodology to a beta-plane and in this talk we present results from our preliminary work to do just that. This is done numerically using spectral methods to find the most accurate solutions possible for a given number of degrees of freedom. First, we determine the structure of the linear RSW modes on a beta-plane in meridional channel. In the continuous limit these waves form a complete basis and are a natural set of basis functions to study in this model and have extensions in other models. Second, we present results from a series of numerical experiments of both freely-evolving and forced flows, to address how energy is transferred between the linear waves. This will consist of wave-wave interactions as well as geostrophic turbulent flows.

Poulin, Francis; Waite, Michael; Greig, Daniel

2013-04-01

46

The Role of Soil Fauna for Decomposition of Plant Residues  

Microsoft Academic Search

\\u000a The organic remains of plants and animals on the soil surface or in the soil are termed litter. This includes leaves, twigs,\\u000a fruits, fructescences, bracts, scales of buds, bark flakes and even whole trees, dead roots, carrion and other resource types.\\u000a Dead materials still attached to the living plants are distinguished from litter as ‘standing dead’. Comprehensive reviews\\u000a of plant

M. Schaefer; S. Migge-Kleian; S. Scheu

47

Monitoring power plant water chemistry  

Microsoft Academic Search

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.

Pocock

1981-01-01

48

Plant Leaf Residue Decomposition, Nutrient Release and Soil Enzyme Activity  

Microsoft Academic Search

We studied the impact of plant leaf residue decompo sition and nutrient release of nitrogen and phosphorus of two weed species - Imperata cylindrica and Chromolaena odorata - and one native forest species - Phyllanthus discoideus - on soil enzyme activities in a pot experiment in the humid tropics of central Cameroon. We tested th e impact of plant leaf

Julia Dux; Lindsey Norgrove; Stefan Hauser; Barbara Wick; Ronald Kühne

49

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

Microsoft Academic Search

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),

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

2007-01-01

50

Decomposition of macroalgae, vascular plants and sediment detritus in seawater: Use of stepwise thermogravimetry  

Microsoft Academic Search

The applicability of a recently presented method (Stepwise Thermogravimetry, STG) to characterize biogenic organic matter (Kristensen 1990) was tested in comparative decomposition experiments. The initial microbial decay of pre-dried, fresh detritus from 6 different plant materials (2 macroalgae, 2 seagrasses, and 2 tree leaves) was examined for 70 days in aerobic seawater slurries. In addition, slurries of sediment detritus of

E. Kristensen

1994-01-01

51

Dynamics of the Methanogenic Archaeal Community during Plant Residue Decomposition in an Anoxic Rice Field Soil  

Microsoft Academic Search

Incorporation of plant residues strongly enhances the methane production and emission from flooded rice fields. Temperature and residue type are important factors that regulate residue decomposition and CH4 production. However, the response of the methanogenic archaeal community to these factors in rice field soil is not well understood. In the present experiment, the structure of the archaeal community was determined

Jingjing Peng; Zhe Lu; Junpeng Rui; Yahai Lu

2008-01-01

52

Waste Water Plant Operators Manual.  

ERIC Educational Resources Information Center

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…

Washington State Coordinating Council for Occupational Education, Olympia.

53

Plant controls on decomposition rates: the benefits of restoring abandoned agricultural lands with native prairie grasses  

Microsoft Academic Search

Plant species can both directly and indirectly affect soil processes in various ways, including through functional traits\\u000a related to the quantity and chemistry of biomass produced. Understanding how functional traits affect soil processes may be\\u000a particularly important in restorations that specifically select a target plant community. In this study, I examined how species\\u000a differing in litter traits alter decomposition, both

Wendy M. Mahaney

2010-01-01

54

Decomposition of two haloacetic acids in water using UV radiation, ozone and advanced oxidation processes  

Microsoft Academic Search

The decomposition of two haloacetic acids (HAAs), dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA), from water was studied by means of single oxidants: ozone, UV radiation; and by the advanced oxidation processes (AOPs) constituted by combinations of O3\\/UV radiation, H2O2\\/UV radiation, O3\\/H2O2, O3\\/H2O2\\/UV radiation. The concentrations of HAAs were analyzed at specified time intervals to elucidate the decomposition of HAAs.

Kunping Wang; Jinsong Guo; Min Yang; Hirotsuji Junji; Rongsen Deng

2009-01-01

55

Effect of air in the thermal decomposition of 50 mass% hydroxylamine\\/water  

Microsoft Academic Search

This paper presents experimental measurements of 50mass% hydroxylamine (HA)\\/water thermal decomposition in air and vacuum environments using an automatic pressure tracking adiabatic calorimeter (APTAC). Overall kinetics, onset temperatures, non-condensable pressures, times to maximum rate, heat and pressure rates versus temperature, and mixture vapor pressures for the experiments in vacuum were similar when compared to the corresponding data for HA decomposition

Lizbeth O Cisneros; William J Rogers; M. S Mannan

2002-01-01

56

Effect of supercritical water density on the rate constant of aliphatic nitrocompounds decomposition  

Microsoft Academic Search

It was shown experimentally that the rate of aliphatic nitrocompounds decomposition in supercritical water (SCW) depends on pressure\\/density at constant temperature. The SCW density dependence of the apparent rate constant of decomposition for each of three compounds under consideration (nitromethane, nitroethane and 1-nitropropane) was found to correlate with the density dependence of the H3O+ concentration in dissociated SCW. The rate

V. I. Anikeev; A. Yermakova; V. A. Semikolenov; M. Goto

2005-01-01

57

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

SciTech Connect

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.

Kabyemela, B.M.; Adschiri, T.; Malaluan, R.M.; Arai, K. [Tohoku Univ., Sendai (Japan). Dept. of Chemical Engineering

1999-08-01

58

Transpiration: Water Movement Through Plants  

NSDL National Science Digital Library

Learn the basics of transpiration -- the transportation of water through plants from soil to leaves to atmosphere -- with this playful animation created by weed physiologist Tracy Sterling and animator Matt Byrnes. Interactive features allow you to explore the process including how changing environmental conditions can impact how fast water moves.

Tracy Sterling (New Mexico State University;)

2005-09-23

59

New tantalate photocatalysts for water decomposition into H 2 and O 2  

Microsoft Academic Search

Photocatalytic activities for the decomposition of distilled water into H2 and O2 were investigated on various tantalates. In the alkali and alkaline earth tantalates, LiTaO3, NaTaO3, KTaO3, MgTa2O6, and BaTa2O6 showed photocatalytic activities for water decomposition without co-catalysts. Among them, BaTa2O6 in the orthorhombic phase was the most active. The addition of a small amount of Ba(OH)2 into the water

Hideki Kato; Akihiko Kudo

1998-01-01

60

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

DOEpatents

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.

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

1983-02-08

61

Use of solar energy for direct and two-step water decomposition cycles  

Microsoft Academic Search

The feasibility of using concentrated solar energy at high temperatures to decompose water is experimentally demonstrated. Preliminary studies show that direct decomposition of water at 2000-2500 C is possible and that the main development should be directed toward reactor design and the separation of product gases. On the other hand, it is shown that two-step thermochemical cycles for hydrogen production

E. Bilgen; M. Ducarroir; M. Foex; F. Sibieude; F. Trombe

1977-01-01

62

Water quality time series for Big Melen stream (Turkey): its decomposition analysis and comparison to upstream  

Microsoft Academic Search

Big Melen stream is one of the major water resources providing 268 km3 year???1 of drinking and municipal water for Istanbul. Monthly time series data between 1991 and 2004 for 25 chemical, biological,\\u000a and physical water properties of Big Melen stream were separated into linear trend, seasonality, and error components using\\u000a additive decomposition models. Water quality index (WQI) derived from 17

N. Karakaya; F. Evrendilek

2010-01-01

63

Water quality time series for Big Melen stream (Turkey): its decomposition analysis and comparison to upstream.  

PubMed

Big Melen stream is one of the major water resources providing 0.268 [corrected] km(3) year(-1) of drinking and municipal water for Istanbul. Monthly time series data between 1991 and 2004 for 25 chemical, biological, and physical water properties of Big Melen stream were separated into linear trend, seasonality, and error components using additive decomposition models. Water quality index (WQI) derived from 17 water quality variables were used to compare Aksu upstream and Big Melen downstream water quality. Twenty-six additive decomposition models of water quality time series data including WQI had R (2) values ranging from 88% for log(water temperature) (P < or = 0.001) to 3% for log(total dissolved solids) (P < or = 0.026). Linear trend models revealed that total hardness, calcium concentration, and log(nitrite concentration) had the highest rate of increase over time. Tukey's multiple comparison pointed to significant decreases in 17 water quality variables including WQI of Big Melen downstream relative to those of Aksu upstream (P < or = 0.001). Monitoring changes in water quality on the basis of watersheds through WQI and decomposition analysis of time series data paves the way for an adaptive management process of water resources that can be tailored in response to effectiveness and dynamics of management practices. PMID:19444637

Karakaya, N; Evrendilek, F

2009-05-12

64

Dual role of lignin in plant litter decomposition in terrestrial ecosystems  

PubMed Central

Plant litter decomposition is a critical step in the formation of soil organic matter, the mineralization of organic nutrients, and the carbon balance in terrestrial ecosystems. Biotic decomposition in mesic ecosystems is generally negatively correlated with the concentration of lignin, a group of complex aromatic polymers present in plant cell walls that is recalcitrant to enzymatic degradation and serves as a structural barrier impeding microbial access to labile carbon compounds. Although photochemical mineralization of carbon has recently been shown to be important in semiarid ecosystems, litter chemistry controls on photodegradative losses are not understood. We evaluated the importance of litter chemistry on photodegradation of grass litter and cellulose substrates with varying levels of lignin [cellulose-lignin (CL) substrates] under field conditions. Using wavelength-specific light attenuation filters, we found that light-driven mass loss was promoted by both UV and visible radiation. The spectral dependence of photodegradation correlated with the absorption spectrum of lignin but not of cellulose. Field incubations demonstrated that increasing lignin concentration reduced biotic decomposition, as expected, but linearly increased photodegradation. In addition, lignin content in CL substrates consistently decreased in photodegradative incubations. We conclude that lignin has a dual role affecting litter decomposition, depending on the dominant driver (biotic or abiotic) controlling carbon turnover. Under photodegradative conditions, lignin is preferentially degraded because it acts as an effective light-absorbing compound over a wide range of wavelengths. This mechanistic understanding of the role of lignin in plant litter decomposition will allow for more accurate predictions of carbon dynamics in terrestrial ecosystems.

Austin, Amy T.; Ballare, Carlos L.

2010-01-01

65

Dual role of lignin in plant litter decomposition in terrestrial ecosystems.  

PubMed

Plant litter decomposition is a critical step in the formation of soil organic matter, the mineralization of organic nutrients, and the carbon balance in terrestrial ecosystems. Biotic decomposition in mesic ecosystems is generally negatively correlated with the concentration of lignin, a group of complex aromatic polymers present in plant cell walls that is recalcitrant to enzymatic degradation and serves as a structural barrier impeding microbial access to labile carbon compounds. Although photochemical mineralization of carbon has recently been shown to be important in semiarid ecosystems, litter chemistry controls on photodegradative losses are not understood. We evaluated the importance of litter chemistry on photodegradation of grass litter and cellulose substrates with varying levels of lignin [cellulose-lignin (CL) substrates] under field conditions. Using wavelength-specific light attenuation filters, we found that light-driven mass loss was promoted by both UV and visible radiation. The spectral dependence of photodegradation correlated with the absorption spectrum of lignin but not of cellulose. Field incubations demonstrated that increasing lignin concentration reduced biotic decomposition, as expected, but linearly increased photodegradation. In addition, lignin content in CL substrates consistently decreased in photodegradative incubations. We conclude that lignin has a dual role affecting litter decomposition, depending on the dominant driver (biotic or abiotic) controlling carbon turnover. Under photodegradative conditions, lignin is preferentially degraded because it acts as an effective light-absorbing compound over a wide range of wavelengths. This mechanistic understanding of the role of lignin in plant litter decomposition will allow for more accurate predictions of carbon dynamics in terrestrial ecosystems. PMID:20176940

Austin, Amy T; Ballaré, Carlos L

2010-02-22

66

Temperature and plant species control over litter decomposition in Alaskan tundra  

SciTech Connect

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.

Hobbie, S.E. [Univ. of California, Berkeley, CA (United States)

1996-11-01

67

Decomposition of water-insoluble organic waste by water plasma at atmospheric pressure  

NASA Astrophysics Data System (ADS)

The water plasma was generated in atmospheric pressure with the emulsion state of 1-decanol which is a source of soil and ground water pollution. In order to investigate effects of operating conditions on the decomposition of 1-decanol, generated gas and liquid from the water plasma treatment were analysed in different arc current and 1-decanol concentration. The 1-decanol was completely decomposed generating hydrogen, carbon monoxide, carbon dioxide, methane, treated liquid and solid carbon in all experimental conditions. The feeding rate of 1- decanol emulsion was increased with increasing the arc current in virtue of enhanced input power. The generation rate of gas and the ratio of carbon dioxide to carbon monoxide were increased in the high arc current, while the generation rate of solid carbon was decreased due to enhanced oxygen radicals in the high input power. Generation rates of gas and solid carbon were increased at the same time with increasing the concentration of 1-decanol, because carbon radicals were increased without enhancement of oxygen radicals in a constant power level. In addition, the ratio of carbon dioxide to carbon monoxide was increased along with the concentration of 1-decanol due to enhanced carbon radicals in the water plasma flame.

Choi, S.; Watanabe, T.

2012-12-01

68

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

PubMed

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

Dresbøll, Dorte Bodin; Magid, Jakob

2005-06-28

69

[Influence of decomposition of Cladophora sp. on phosphorus concentrations and forms in the overlying water].  

PubMed

Sediments were sampled in the dominated zone of Cladophora sp. in Rongcheng Swan Lake, and cultivated with algae in the laboratory to reveal the influence of Cladophora decomposition on concentrations and forms of phosphorus in the overlying water. Concentrations of total phosphorus (TP), dissolved total phosphorus (DTP), soluble reactive phosphorus (SRP), particulate phosphorus (PP) and dissolved organic phosphorus (DOP) in overlying water were investigated, and some physicochemical parameters, such as dissolved oxygen (DO), pH and conductivity were monitored during the experiment. In addition, the influence of algae decomposition on P release from sediments was analyzed. Due to the decomposition of Cladophora, DO concentration in the overlying water declined remarkably and reached the anoxic condition (0-0.17 mg x L(-1)). The pH value of different treatments also decreased, and treatments with algae reduced by about 1 unit. Concentrations of TP and different P forms all increased obviously, and the increasing extent was larger with the adding algae amount. TP concentrations of different treatments varied from 0.04 mg x L(-1) to 1.34 mg x L(-1). DOP and PP were the main P forms in the overlying water in algae without sediments treatments, but SRP concentrations became much higher in algae with sediments treatments. The result showed that P forms released from decomposing Cladophora were mainly DOP and PP, and the Cladophora decomposition could also promote the sediments to release P into the overlying water. PMID:23947031

Hou, Jin-Zhi; Wei, Quan; Gao, Li; Sun, Wei-Ming

2013-06-01

70

Seasonal variation in nitrogen isotopic composition of bog plant litter during 3 years of field decomposition  

Microsoft Academic Search

In this study, we describe the seasonal variation in 15N abundance in the litter of two Sphagnum species and four vascular plant species during 3 years of field decomposition in an Italian Alpine bog. Litter bags were\\u000a periodically retrieved at the end of summer and winter periods, and the ?15N in residual litter was related to mass loss, litter chemistry, and

Luca Bragazza; Paola Iacumin; Chiara Siffi; Renato Gerdol

2010-01-01

71

Seasonal variation in carbon isotopic composition of bog plant litter during 3 years of field decomposition  

Microsoft Academic Search

In this study, we describe the seasonal variation in 13C abundance in the litter of two Sphagnum species and four vascular plant species during 3 years of field decomposition in an Italian alpine bog. Litter bags were\\u000a periodically retrieved at the end of summer and winter periods, and the ?13C in residual litter was related to mass loss, litter chemistry, and

Luca Bragazza; Paola Iacumin

2009-01-01

72

Decomposition of cellulose, soil organic matter and plant litter in a temperate grassland soil  

Microsoft Academic Search

The formation of mor humus in an experimental grassland plot, which has been acidified by long-term fertiliser treatment,\\u000a has been studied by comparing the rates of cellulose, soil organic matter and plant litter decay with those in an adjacent\\u000a plot with near-neutral pH and mull humus. The decomposition of cellulose filter paper in litter bags of 5 mm, 1-mm and

D. W. Hopkins; D. M. Ibrahim; A. G. O'donnell; R. S. Shiel

1990-01-01

73

Decomposition in soil of soluble, insoluble and lignin-rich fractions of plant material from tobacco with genetic modifications to lignin biosynthesis  

Microsoft Academic Search

The decomposition in soil of pieces of stem and different fractions of stems from uniformly-grown tobacco plants with genetic modifications to lignin biosynthesis was investigated by measuring CO2 production over 74d. The fractions used were intact stems, the insoluble fraction obtained by washing the stems with water, the lignin-rich fraction obtained by dissecting away the epidermis and cortex from the

E. A. Webster; C. Halpin; J. A. Chudek; E. L. Tilston; D. W. Hopkins

2005-01-01

74

Decomposition of Phenol in Water by Gas Phase Pulse Discharge Plasma  

Microsoft Academic Search

This paper introduced a pulse discharge reactor with a novel electrode configuration for decomposition of phenol in water. A tungsten wire in the middle of the porous ceramic tube and a stainless steel mesh outside the ceramic tube attached to the inner wall of the reactor vessel were constructed as discharge electrode and ground electrode, respectively. The porous ceramic tube

Yan Wu; Jie Li; Guo-Feng Li; Nan Li; Guang-Zhou Qu; Chang-Hai Sun; Masayuki Sato

2009-01-01

75

Oxidative decomposition of vitamin C in drinking water.  

PubMed

We have previously shown that vitamin C (ascorbic acid) can initiate hydroxyl radical formation in copper contaminated household drinking water. In the present study, we have examined the stability of vitamin C in copper and bicarbonate containing household drinking water. In drinking water samples, contaminated with copper from the pipes and buffered with bicarbonate, 35% of the added vitamin C was oxidized to dehydroascorbic acid within 15 min. After 3h incubation at room temperature, 93% of the added (2 mM) ascorbic acid had been oxidized. The dehydroascorbic acid formed was further decomposed to oxalic acid and threonic acid by the hydrogen peroxide generated from the copper (I) autooxidation in the presence of oxygen. A very modest oxidation of vitamin C occurred in Milli-Q water and in household water samples not contaminated by copper ions. Moreover, addition of vitamin C to commercially sold domestic bottled water samples did not result in vitamin C oxidation. Our results demonstrate that ascorbic acid is rapidly oxidized to dehydroascorbic acid and further decomposed to oxalic- and threonic acid in copper contaminated household tap water that is buffered with bicarbonate. The impact of consuming ascorbic acid together with copper and bicarbonate containing drinking water on human health is discussed. PMID:15493459

Jansson, Patric J; Jung, Hye R; Lindqvist, Christer; Nordström, Tommy

2004-08-01

76

Carbon isotopic fractionation during decomposition of plant materials of different quality  

NASA Astrophysics Data System (ADS)

Changes in isotopic 13C composition of solid residues and CO2 evolved during decomposition of C3 and C4 plant materials were monitored over 10 months to determine carbon isotopic fractionation at successive stages of biodegradation. We selected plant materials of different chemical quality, e.g., Zea mays (leaves, stems, coarse roots, and fine roots), Lolium perenne (leaves and roots), Pinus pinaster (needles), and Cocos nucifera (coconut shell) and also characterized these by solid-state 13C NMR. Roots were more lignified than aerial parts of the same species. Lignin was always depleted in 13C (up to 5.2‰) as compared with cellulose from the same sample. Proteins were enriched in 13C in C3 plants but depleted in maize. Cumulative CO2 evolved fitted a double-exponential model with two C pools of different lability. During early stages of decomposition, the CO2-C released was usually 13C depleted as compared with the initial substrate but enriched at posterior stages. Consequently, with ongoing decomposition, the solid residue became 13C depleted, which could only partly be explained by an accumulation of lignin-C. The extension of the initial 13C depleted CO2-C phase was significantly correlated with the labile substrate C content, acid-detergent soluble fraction, and total N, pointing to a direct influence of plant quality on C isotopic dynamics during early stages of biodegradation. This isotopic fractionation can also lead to an underestimation of the contribution of plant residues to CO2-C when incubated in soils. We discuss possible implications of these mechanisms of 13C fractionation in ecosystems.

Fernandez, I.; Mahieu, N.; Cadisch, G.

2003-09-01

77

Methane–ethane and methane–propane hydrate formation and decomposition on water droplets  

Microsoft Academic Search

Gas hydrate formation and decomposition on water droplets using an 89.4% methane—10.6% ethane mixture, and a 90.1% methane—9.9% propane mixture were carried out in a new apparatus suitable for morphology studies. As expected the induction time was found to be much shorter when the water had hydrate memory. All droplets nucleated simultaneously and the droplet size and shape had no

Ju Dong Lee; Robin Susilo; Peter Englezos

2005-01-01

78

PLANT WATER STATUS INFLUENCES OZONE SENSITIVITY OF BEAN PLANTS  

EPA Science Inventory

Studies were conducted in a controlled environment chamber to determine the association between plant water status and ozone sensitivity. Bean plants were subjected to various water stress regimes for 4 to 10 days using a semipermeable membrane system which controlled plant water...

79

Theoretical study of the decomposition of formamide in the presence of water molecules.  

PubMed

Formamide (NH2CHO, FM) has been considered an active key precursor in prebiotic chemistry on early Earth. Under certain conditions such as dry lagoons, FM can decompose to produce reactants that lead to formation of more complex biomolecules. Specifically, FM decomposition follows many reactive channels producing small molecules such as H2, CO, H2O, HCN, HNC, NH3, and HNCO with comparable energy barriers in the range of 73-82 kcal/mol. Due to the likely presence of water on prebiotic Earth and the intrinsic presence of water following FM decomposition, we explore the effects of water oligomers, (H2O)n with n = 1-3, on its dehydration, dehydrogenation, and decarbonylation reactions using quantum chemical computations. Geometries are optimized using MP2/aug-cc-pVxZ calculations (x = D,T), and relative energies are evaluated using coupled-cluster theory CCSD(T) with the aug-cc-pVxZ basis sets (x = D, T, Q). Where possible the coupled-cluster energies are extrapolated to the complete basis set limit (CBS). Water classically acts as an efficient bifunctional catalyst for decomposition. With the presence of one water molecule, the dehydration pathway leading to HCN is favored. When two and three water molecules are involved, dehydration remains energetically favored over other channels and attains an energy barrier of ~30 kcal/mol. PMID:23461351

Nguyen, Vinh Son; Orlando, Thomas M; Leszczynski, Jerzy; Nguyen, Minh Tho

2013-03-18

80

Novel Catalytic Behavior of Water in High Explosive Decomposition  

NASA Astrophysics Data System (ADS)

Water under conditions of extremely high pressure and temperature is known to exhibit fascinating physical behaviors. Its remarkable structural and phase complexity strongly suggests that its chemical properties, which are largely unstudied, may be unusual as well. Detonations of high explosives containing oxygen and hydrogen provide unique systems for exploring the chemistry of ``extreme water,'' because detonations form water at conditions similar to those of giant planetary interiors. Contrary to the current view of water as a stable final product, we show here that water plays an unexpected role in catalyzing complex explosive reactions. From first-principles atomistic simulations of the high explosive pentaerythritol tetranitrate (PETN), we discovered that H2O (source), H (reducer) and OH (oxidizer) act as a dynamic team that transports oxygen between reactive centers. Our finding suggests that H2O may catalyze reactions in other explosives and in planetary interiors. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

Fried, Laurence; Wu, Christine; Yang, Lin; Goldman, Nir; Bastea, Sorin

2009-06-01

81

Microscopic properties of liquid water from combined ab initio molecular dynamics and energy decomposition studies.  

PubMed

The application of newly developed first-principle modeling techniques to liquid water deepens our understanding of the microscopic origins of its unusual macroscopic properties and behaviour. Here, we review two novel ab initio computational methods: second-generation Car-Parrinello molecular dynamics and decomposition analysis based on absolutely localized molecular orbitals. We show that these two methods in combination not only enable ab initio molecular dynamics simulations on previously inaccessible time and length scales, but also provide unprecedented insights into the nature of hydrogen bonding between water molecules. We discuss recent applications of these methods to water clusters and bulk water. PMID:23928575

Khaliullin, Rustam Z; Kühne, Thomas D

2013-08-09

82

Plant-driven variation in decomposition rates improves projections of global litter stock distribution  

NASA Astrophysics Data System (ADS)

Plant litter stocks are critical, regionally for their role in fueling fire regimes and controlling soil fertility, and globally through their feedback to atmospheric CO2 and climate. Here we employ two global databases linking plant functional types to decomposition rates of wood and leaf litter (Cornwell et al., 2008; Weedon et al., 2009) to improve future projections of climate and carbon cycle using an intermediate complexity Earth system model. Implementing separate wood and leaf litter decomposabilities and their temperature sensitivities for a range of plant functional types yielded a more realistic distribution of litter stocks in all present biomes with except of boreal forests and projects a strong increase in global litter stocks and a concomitant small decrease in atmospheric CO2 by the end of this century. Despite a relatively strong increase in litter stocks, the modified parameterization results in less elevated wildfire emissions because of litter redistribution towards more humid regions.

Brovkin, V.; van Bodegom, P. M.; Kleinen, T.; Wirth, C.; Cornwell, W.; Cornelissen, J. H. C.; Kattge, J.

2011-08-01

83

Influence of soil temperature and water tension on the decomposition rate of ¹⁴Ca labeled herbage  

Microsoft Academic Search

The relation of decomposition rate of carbon-14 labeled blue grama (Bouteloua gracilis) to soil water content and temperature was examined in laboratory studies. Soil samples amended with ground herbage were incubated at various temperatures (3, 10, 25, 40, 50, and 60°C and water contents (.009, .03, .06, .60, 5.8, and 113 atm water tension). The oxygen concentrations in the decomposition

J. W. NYHAN

1976-01-01

84

Role of iron surface oxidation layers in decomposition of azo-dye water pollutants in weak acidic solutions  

Microsoft Academic Search

While decomposition of water pollutants in the presence of metallic iron can be strongly influenced by the nature and structure of the iron surface layer, the composition and structure of the layer produced and transformed in the decomposition process, have been meagerly investigated. The studies presented here establish strong relationships between the composition and structure of the iron oxidized surface

Jerzy A. Mielczarski; Gonzalo Montes Atenas; Ela Mielczarski

2005-01-01

85

High sensitivity of peat decomposition to climate change through water-table feedback  

NASA Astrophysics Data System (ADS)

Historically, northern peatlands have functioned as a carbon sink, sequestering large amounts of soil organic carbon, mainly due to low decomposition in cold, largely waterlogged soils. The water table, an essential determinant of soil-organic-carbon dynamics, interacts with soil organic carbon. Because of the high water-holding capacity of peat and its low hydraulic conductivity, accumulation of soil organic carbon raises the water table, which lowers decomposition rates of soil organic carbon in a positive feedback loop. This two-way interaction between hydrology and biogeochemistry has been noted, but is not reproduced in process-based simulations. Here we present simulations with a coupled physical-biogeochemical soil model with peat depths that are continuously updated from the dynamic balance of soil organic carbon. Our model reproduces dynamics of shallow and deep peatlands in northern Manitoba, Canada, on both short and longer timescales. We find that the feedback between the water table and peat depth increases the sensitivity of peat decomposition to temperature, and intensifies the loss of soil organic carbon in a changing climate. In our long-term simulation, an experimental warming of 4?C causes a 40% loss of soil organic carbon from the shallow peat and 86% from the deep peat. We conclude that peatlands will quickly respond to the expected warming in this century by losing labile soil organic carbon during dry periods.

Ise, Takeshi; Dunn, Allison L.; Wofsy, Steven C.; Moorcroft, Paul R.

2008-11-01

86

Method of generating hydrogen by catalytic decomposition of water  

DOEpatents

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.

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

87

Water Treatment Technology - General Plant Operation.  

ERIC Educational Resources Information Center

One of twelve water treatment technology units, this student manual on general plant operations provides instructional materials for seven competencies. (The twelve units are designed for a continuing education training course for public water supply operators.) The competencies focus on the following areas: water supply regulations, water plant…

Ross-Harrington, Melinda; Kincaid, G. David

88

Early diagenesis of vascular plant tissues: Lignin and cutin decomposition and biogeochemical implications  

NASA Astrophysics Data System (ADS)

Long-term subaqueous decomposition patterns of five different vascular plant tissues including mangrove leaves and wood ( Avicennia germinans ), cypress needles and wood ( Taxodium distichum ) and smooth cordgrass ( Spartina alternifora ) were followed for a period of 4.0 years, representing the longest litter bag decomposition study to date. All tissues decomposed under identical conditions and final mass losses were 97, 68, 86, 39, and 93%, respectively. Analysis of the lignin component of herbaceous tissues using alkaline CuO oxidation was complicated by the presence of a substantial ester-bound phenol component composed primarily of cinnamyl phenols. To overcome this problem, we introduce a new parameter to represent lignin, 6 . 6 is comprised only of the six syringyl and vanillyl phenols and was found to be much less sensitive to diagenetic variation than the commonly used parameter , which includes the cinnamyl phenols. Patterns of change in lignin content were strongly dependent on tissue type, ranging from 77% enrichment in smooth cordgrass to 6% depletion in cypress needles. In contrast, depletion of cutin was extensive (65-99%) in all herbaceous tissues. Despite these differences in the overall reactivity of lignin and cutin, both macromolecules were extensively degraded during the decomposition period. The long-term decomposition series also provided very useful information about the compositional parameters which are derived from the specific oxidation products of both lignin and cutin. The relative lability of ester-bound cinnamyl phenols compromised their use in parameters to distinguish woody from herbaceous plant debris. The dimer to monomer ratios of lignin-derived phenols indicated that most intermonomeric linkages in lignin degraded at similar rates. Acid to aldehyde ratios of vanillyl and syringyl phenols became elevated, particularly during the latter stages of decomposition supporting the use of these parameters as indicators of diagenetic alteration. Given the observation that cutin-derived source indicator parameters were generally more sensitive to diagenetic alteration than those of lignin, we suggest the distributional patterns of cutin-derived acids and their associated positional isomers may be most useful for tissue-specific distinctions complementing the general categorical information obtained from lignin phenol analysis alone.

Opsahl, Stephen; Benner, Ronald

1995-12-01

89

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

PubMed

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

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

2006-06-30

90

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

PubMed

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

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

2013-06-20

91

Carbon dioxide enrichment and nitrogen fertilization effects on cotton (Gossypium hirsutum L.) plant residue chemistry and decomposition  

Microsoft Academic Search

Increased atmospheric carbon dioxide (CO2) concentration will likely cause changes in plant productivity and composition that might affect soil decomposition processes.\\u000a The objective of this study was to test to what extent elevated CO2 and N fertility-induced changes in residue quality controlled decomposition rates. Cotton (Gossypium hirsutum L.) was grown in 8-l pots and exposed to two concentrations of CO2

Fitzgerald L. Booker; Steven R. Shafer; Cai-Miao Wei; Stephanie J. Horton

2000-01-01

92

Decomposition dynamics and structural plant components of genetically modified Bt maize leaves do not differ from leaves of conventional hybrids.  

PubMed

The cultivation of genetically modified Bt maize has raised environmental concerns, as large amounts of plant residues remain in the field and may negatively impact the soil ecosystem. In a field experiment, decomposition of leaf residues from three genetically modified (two expressing the Cry1Ab, one the Cry3Bb1 protein) and six non-transgenic hybrids (the three corresponding non-transformed near-isolines and three conventional hybrids) was investigated using litterbags. To elucidate the mechanisms that cause differences in plant decomposition, structural plant components (i.e., C:N ratio, lignin, cellulose, hemicellulose) were examined. Furthermore, Cry1Ab and Cry3Bb1 protein concentrations in maize leaf residues were measured from harvest to the next growing season. While leaf residue decomposition in transgenic and non-transgenic plants was similar, differences among conventional cultivars were evident. Similarly, plant components among conventional hybrids differed more than between transgenic and non-transgenic hybrids. Moreover, differences in senescent plant material collected directly from plants were larger than after exposure to soil for 5 months. While the concentration of Cry3Bb1 was higher in senescent maize leaves than that of Cry1Ab, degradation was faster, indicating that Cry3Bb1 has a shorter persistence in plant residues. As decomposition patterns of Bt-transgenic maize were shown to be well within the range of common conventional hybrids, there is no indication of ecologically relevant, adverse effects on the activity of the decomposer community. PMID:19609704

Zurbrügg, Corinne; Hönemann, Linda; Meissle, Michael; Romeis, Jörg; Nentwig, Wolfgang

2009-07-17

93

The Presence of Plants Alters the Effect of Soil Moisture on Soil C Decomposition in Two Different Soil Types  

NASA Astrophysics Data System (ADS)

While it is well known that soil moisture directly affects microbial activity and soil C decomposition, it is unclear if the presence of plants alters these effects through rhizosphere processes. We studied soil moisture effects on soil C decomposition with and without sunflower and soybean. Plants were grown in two different soil types with soil moisture contents of 45 and 85% of field capacity in a greenhouse experiment. We continuously labeled plants with depleted 13C, which allowed us to separate plant-derived CO2-C from original soil-derived CO2-C in soil respiration measurements. We observed an overall increase in soil-derived CO2-C efflux in the presence of plants (priming effect) in both soils with on average a greater priming effect in the high soil moisture treatment (60% increase in soil-derived CO2-C compared to control) than in the low soil moisture treatment (37% increase). Greater plant biomass in the high soil moisture treatment contributed to greater priming effects, but priming effects remained significantly higher after correcting for plant biomass. Possibly, root exudation of labile C may have increased more than plant biomass and may have become more effective in stimulating microbial decomposition in the higher soil moisture treatment. Our results indicate that changing soil moisture conditions can significantly alter rhizosphere effects on soil C decomposition.

Dijkstra, F. A.; Cheng, W.

2005-12-01

94

Photocatalytic decomposition of water over NiO-KâNbâOââ catalyst  

Microsoft Academic Search

Photocatalytic decomposition of HâO to form Hâ and Oâ over NiO-KâNbâOââ powder (1-10 ..mu..m, band gap = 3.3 eV), which is an ion-exchange layered compound, proceeds steadily more than 50 h under the bandgap irradiation. Maximum activity was obtained when the reaction was carried out in distilled water where the pH was ca. 11 by elution of K\\/sup +\\/ and

A. Kudo; A. Tanaka; K. Domen; K. Maruya; K. Aika; T. Onishi

1988-01-01

95

Iterative decomposition of water and fat with echo asymmetry and least square estimation  

US Patent & Trademark Office Database

A method of separating signals from water and lipid in a body using spin-echo magnetic resonance imaging comprising steps of acquiring image signals at three acquisition times asymmetrically positioned with respect to a spin-echo time, the three acquisition times being separated by 2.pi./3 and the middle signal acquisition is centered at .pi./2+.pi.k where k is an integer, and combining the plurality of image signals iterative using a least squares decomposition method.

2007-02-13

96

Hydrothermal decomposition of pentachlorophenol in subcritical and supercritical water with sodium hydroxide addition  

Microsoft Academic Search

Hydrothermal decomposition of pentachlorophenol (PCP, C6HCl5O), as the probable human carcinogen, was investigated in a tubular reactor under subcritical and supercritical water with sodium hydroxide (NaOH) addition. The experiments were conducted at a temperature range of 300–420°C and a fixed pressure of 25 MPa, with a residence time that ranged from 10 s to 70 s. Under the reaction conditions,

Benedictus PRABOWO; Bambang VERIANSYAH; Jae-Duck KIM

2007-01-01

97

Fructose decomposition kinetics in organic acids-enriched high temperature liquid water  

Microsoft Academic Search

Biomass continues to be an important candidate as a renewable resource for energy, chemicals, and feedstock. Decomposition of biomass in high temperature liquid water is a promising technique for producing industrially important chemicals such as 5-hydroxymethylfurfural (5-HMF), furfural, levulinic acid with high efficiency. Hexose, which is the hydrolysis product of cellulose, will be one of the most important starting chemicals in the

Yinghua Li; Xiuyang Lu; Lei Yuan; Xin Liu

2009-01-01

98

Photoassisted decomposition of water over doped rutile electrodes  

NASA Astrophysics Data System (ADS)

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.

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

99

Modeling macrophyte decompositions in Lake Baiyangdian, China  

NASA Astrophysics Data System (ADS)

Detritus decomposition is a critical process in eutrophic shallow lakes, since it can influence accumulation of the sediment layer at lake bottoms and regulate lake terrestrialization in the long run. However, characteristics of macrophyte decomposition in nutrient enriched aquatic ecosystems have not yet been well explored. In order to better understand how plant detritus decomposition would respond to nutrient increase in eutrophic shallow lakes, a process based ecosystem model has built to simulate major macrophyte decompositions in Lake Baiyangdian based on our field works. The model is composed of four components, including hydrology, plant physiology, water chemistry, and sediment biochemistry. In the model, the sediment biochemistry considers nutrient and carbon dynamics as well as detritus accumulation from macrophytes decomposition. Effects of both abiotic factors and biotic factors controlling detritus decomposition were simulated and tested. Calibration and validation of the model were performed using observed data in the lake. Multi-variate sensitivity analysis was used to identify the dominant factors controlling decompositions. Results of this study demonstrate that the model is able to reconstruct decomposition process in the lake. The detritus decomposition processes are sensitive to the phosphorus (P) and nitrogen (N) contents in detritus. Furthermore, the model was employed to predict the long-term effects of water nutrients increase. Enriched water nutrients will greatly enhance plant growth and alter detritus accumulation at the lake bottom. This study may provide some insights for management practices aiming to protect the functioning and structure of the lake ecosystem.

Li, X.; Cui, B.; Tian, H.; Yang, Q.; Chen, G.

2011-12-01

100

Plant responses to water stress  

PubMed Central

Terrestrial plants most often encounter drought stress because of erratic rainfall which has become compounded due to present climatic changes.Responses of plants to water stress may be assigned as either injurious change or tolerance index. One of the primary and cardinal changes in response to drought stress is the generation of reactive oxygen species (ROS), which is being considered as the cause of cellular damage. However, recently a signaling role of such ROS in triggering the ROS scavenging system that may confer protection or tolerance against stress is emerging. Such scavenging system consists of antioxidant enzymes like SOD, catalase and peroxidases, and antioxidant compounds like ascorbate, reduced glutathione; a balance between ROS generation and scavenging ultimately determines the oxidative load. As revealed in case of defence against pathogen, signaling via ROS is initiated by NADPH oxidase-catalyzed superoxide generation in the apoplastic space (cell wall) followed by conversion to hydrogen peroxide by the activity of cell wall-localized SOD. Wall peroxidase may also play role in ROS generation for signaling. Hydrogen peroxide may use Ca2+ and MAPK pathway as downstream signaling cascade. Plant hormones associated with stress responses like ABA and ethylene play their role possibly via a cross talk with ROS towards stress tolerance, thus projecting a dual role of ROS under drought stress.

Kar, Rup Kumar

2011-01-01

101

Efficient decomposition of environmentally persistent perfluorooctanesulfonate and related fluorochemicals using zerovalent iron in subcritical water.  

PubMed

Decomposition of perfluorooctanesulfonate (PFOS) and related chemicals in subcritical water was investigated. Although PFOS demonstrated little reactivity in pure subcritical water, addition of zerovalent metals to the reaction system enhanced the PFOS decomposition to form F-ions, with an increasing order of activity of no metal approximately equal Al < Cu < Zn < Fe. Use of iron led to the most efficient PFOS decomposition: When iron powder was added to an aqueous solution of PFOS (93-372 microM) and the mixture was heated at 350 degrees C for 6 h, PFOS concentration in the reaction solution fell below 2.2 microM (detection limit of HPLC with conductometric detection), with formation of F-ions with yields [i.e., (moles of F- formed)/(moles of fluorine content in initial PFOS) x 100] of 46.2-51.4% and without any formation of perfluorocarboxylic acids. A small amount of CHF3 was detected in the gas phase with a yield [i.e., (moles of CHF3)/(moles of carbon content in initial PFOS) x 100] of 0.7%, after the reaction of PFOS (372 microM) with iron at 350 degree C for 6 h. Spectroscopic measurements indicated that PFOS in water markedly adsorbed on the iron surface even at room temperature, and the adsorbed fluorinated species on the iron surface decomposed with rising temperature, with prominent release of F- ions to the solution phase above 250 degrees C. This method was also effective in decomposing other perfluoroalkylsulfonates bearing shorter chain (C2-C6) perfluoroalkyl groups and was successfully applied to the decomposition of PFOS contained in an antireflective coating agent used in semiconductor manufacturing. PMID:16509356

Hori, Hisao; Nagaoka, Yumiko; Yamamoto, Ari; Sano, Taizo; Yamashita, Nobuyoshi; Taniyasu, Sachi; Kutsuna, Shuzo; Osaka, Issey; Arakawa, Ryuichi

2006-02-01

102

Solar radiation influence on the decomposition process of diclofenac in surface waters.  

PubMed

Diclofenac can be detected in surface water of many rivers with human impacts worldwide. The observed decrease of the diclofenac concentration in waters and the formation of its photochemical transformation products under the impact of natural irradiation during one to 16 days are explained in this article. In semi-natural laboratory tests and in a field experiment it could be shown, that sunlight stimulates the decomposition of diclofenac in surface waters. During one day intensive solar radiation in middle European summer diclofenac decomposes in the surface layer of the water (0 to 5 cm) up to 83%, determined in laboratory exposition experiments. After two weeks in a field experiment, the diclofenac was not detectable anymore in the water surface layer (limit of quantification: 5 ng/L). At a water depth of 50 cm, within two weeks 96% of the initial concentration was degraded, while in 100 cm depth 2/3 of the initial diclofenac concentration remained. With the decomposition, stable and meta-stable photolysis products were formed and observed by UV detection. Beyond that the chemical structure of these products were determined. Three transformation products, that were not described in the literature so far, were identified and quantified with GC-MS. PMID:17258294

Bartels, Peter; von Tümpling, Wolf

2007-01-25

103

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

PubMed

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

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

2011-07-16

104

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...

105

Low temperature water gas shift: the link between the catalysis of WGS and formic acid decomposition over Pt\\/ceria  

Microsoft Academic Search

Partial reduction of the ceria surface leads to the formation of bridging Type II OH groups, as reported previously. These were found to react with formic acid to yield bidentate formate and water, or with CO directly to form bidentate formate. In both WGS and formic acid decomposition via dehydrogenation whereby a high water\\/CO or water\\/formic acid ratio was utilized,

Gary Jacobs; Patricia M. Patterson; Uschi M. Graham; Adam C. Crawford; Burtron H. Davis

2005-01-01

106

Efficient decomposition of perfluorocarboxylic acids and alternative fluorochemical surfactants in hot water.  

PubMed

Decomposition of C5-C9 perfluorocarboxylic acids (PFCAs) and perfluoroether carboxylic acids (alternatives to PFCA-based surfactants) in hot water in a sealed reactor was investigated. Although PFCAs showed almost no decomposition in hot water at 80 degrees C in the absence of persulfate (S2O8(2-)), the addition of S2O8(2-) to the reaction system led to efficient decomposition, even at this relatively low temperature. The major products in the aqueous and gas phases were F- ions and CO2, respectively, and short-chain PFCAs were also detected in the aqueous phase. For example, when an aqueous solution containing perfluorooctanoic acid (PFOA, 374 microM) and S2O8(2-) (50.0 mM) was heated at 80 degrees C for 6 h, PFOA concentration in the aqueous phase fell below 1.52 microM (detection limit of HPLC with conductometric detection), and the yields of F- ions [i.e., (moles of F- formed) /(moles of fluorine content in initial PFOA)] and CO2 [i.e, (moles of CO2 formed) /(moles of carbon content in initial PFOA)] were 77.5% and 70.2%, respectively. This method was also effective in decomposing perfluoroether carboxylic acids, such as CF3OC2F4OCF2COOH, CF3OC2F4OC2F4OCF2COOH, and C2F5OC2F4OCF2COOH, which are alternatives to PFCA-based surfactants, producing F- and CO2 with yields of 82.9-88.9% and 87.7-100%, respectively, after reactions at 80 degrees C for 6 h. In addition, the method was successfully used to decompose perfluorononanoic acid in a floor wax solution. When PFOAwastreated at a higher temperature (150 degrees C), other decomposition reactions occurred: the formation of F- and CO2 was dramatically decreased, and 1H-perfluoroalkanes (C(n)F(2n+1)H, n = 4-7) formed in large amounts. This result clearly indicates that treatment with high-temperature water was not suitable for the decomposition of PFCAs to F-: surprisingly, the relatively low temperature of 80 degrees C was preferable. PMID:18939583

Hori, Hisao; Nagaoka, Yumiko; Murayama, Misako; Kutsuna, Shuzo

2008-10-01

107

Adsorption and decomposition of water-dissolved ozone on high silica zeolites.  

PubMed

The adsorption properties of water-dissolved ozone on high silica zeolites were investigated. Adsorbed ozone was desorbed almost reversibly. The adsorption equilibrium relations were described by a linear expression written as q=betaC, where q is the amount adsorbed, C is the equilibrium concentration and beta is the equilibrium constant. Also, the beta values were strongly dependent on the SiO(2)/Al(2)O(3) ratio (mol/mol) and on the pore structure of the high silica zeolites. The larger the SiO(2)/Al(2)O(3) ratio, the larger the value of beta. ZSM-5 (SiO(2)/Al(2)O(3) ratio: 3000), which gave the highest adsorption capacity of water-dissolved ozone, was able to highly concentrate water-dissolved ozone on the adsorbent. The decomposition behavior of adsorbed ozone was also investigated. Ozone adsorbed on high silica zeolite was observed to be a little more stable than ozone existing in bulk water. The decomposition rate was independent of SiO(2)/Al(2)O(3) ratios in the range of 30-3000 or a solution pH in the range of 4-6. PMID:14630113

Fujita, Hirotaka; Izumi, Jun; Sagehashi, Masaki; Fujii, Takao; Sakoda, Akiyoshi

2004-01-01

108

Chemical additives enhance power plant water treatment  

Microsoft Academic Search

This paper discusses the importance of control systems in power plant water systems. An upgrading of a system in Portland is described. The author presents an artificial intelligence based water chemistry diagnostic system.

Rittenhouse

1989-01-01

109

Water protection in coke-plant design  

SciTech Connect

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.

G.I. Alekseev [Giprokoks, the State Institute for the Design of Coke-Industry Enterprises, Kharkov (Ukraine)

2009-07-15

110

Photocatalytic decomposition of a perfluoroether carboxylic acid by tungstic heteropolyacids in water  

Microsoft Academic Search

The photochemical decomposition of perfluoroether carboxylic acid C2F5OC2F4OCF2COOH (EEA), which is being introduced in industry as a surfactant alternative to environmentally persistent and bioaccumulative perfluorocarboxylic acids, was investigated by use of water-soluble tungstic heteropolyacids H3PW12O40 and H4SiW12O40, and the results were compared with those of conventional techniques, UV–visible light irradiation in the presence of H2O2, treatment with Fenton's reagent, and

Hisao Hori; Ari Yamamoto; Kazuhide Koike; Shuzo Kutsuna; Misako Murayama; Arifumi Yoshimoto; Ryuichi Arakawa

2008-01-01

111

Decomposition of water by a CaTiO{sub 3} photocatalyst under UV light irradiation  

SciTech Connect

Platinized CaTiO{sub 3} powder (band gap 3.5 eV) had a high photocatalytic activity of decomposing water into H{sub 2} and O{sub 2} under the irradiation of UV light, especially with photon energies above 3.8 eV. The existence of this photocatalytic activity is further supported on electrochemical grounds in that the photoinduced current spectrum measured between a CaTiO{sub 3} single crystal and a Pt electrode without applied voltage in water showed a maximum near 4.1 eV. This result indicates that the direct measurement of the spectrum corresponding to the efficiency of water decomposition is an effective method to survey photocatalytic activities of materials.

Mizoguchi, Hiroshi; Ueda, Kazushige; Orita, Masahiro; Moon, Sang-Chul; Kajihara, Koichi; Hirano, Masahiro; Hosono, Hideo

2002-12-01

112

Search for memory effects in methane hydrate: Structure of water before hydrate formation and after hydrate decomposition  

Microsoft Academic Search

Neutron diffraction with H\\/D isotope substitution has been used to study the formation and decomposition of the methane clathrate hydrate. Using this atomistic technique coupled with simultaneous gas consumption measurements, we have successfully tracked the formation of the sI methane hydrate from a water\\/gas mixture and then the subsequent decomposition of the hydrate from initiation to completion. These studies demonstrate

Piers Buchanan; Alan K. Soper; Helen Thompson; Robin E. Westacott; Jefferson L. Creek; Greg Hobson; Carolyn A. Koh

2005-01-01

113

A Fast Iterated Conditional Modes Algorithm for Water-Fat Decomposition in MRI  

PubMed Central

Decomposition of water and fat in Magnetic Resonance Imaging (MRI) is important for biomedical research and clinical applications. In this paper, we propose a two-phased approach for the three-point water-fat decomposition problem. Our contribution consists of two components: (1) a background-masked Markov Random Field (MRF) energy model to formulate the local smoothness of field inhomogeneity; (2) a new Iterated Conditional Modes (ICM) algorithm accounting for high-performance optimization of the MRF energy model. The MRF energy model is integrated with background masking to prevent error propagation of background estimates as well as improve efficiency. The central component of our new ICM algorithm is the Stability Tracking (ST) mechanism intended to dynamically track iterative stability on pixels so that computation per iteration is performed only on instable pixels. The ST mechanism significantly improves the efficiency of ICM. We also develop a median-based initialization algorithm to provide good initial guesses for ICM iterations, and an adaptive gradient-based scheme for parametric configuration of the MRF model. We evaluate the robust of our approach with high-resolution mouse datasets acquired from 7-Tesla MRI.

Huang, Fangping; Narayan, Sreenath; Wilson, David; Johnson, David; Zhang, Guo-Qiang

2013-01-01

114

Localized corrosion of 316L stainless steel in tritiated water containing aggressive radiolytic and decomposition products at different temperatures  

Microsoft Academic Search

Tritium is one of the more important radionuclides used in nuclear industry as plutonium and uranium. The tritium in tritiated water always causes difficulties in nuclear installations, including equipment corrosion. Moreover, with tritiated water there are, in addition, the radiolytic and decomposition products such as hydrogen peroxide formed during decay, chloride ions produced by degradation of organic seals and oils

G. Bellanger

2008-01-01

115

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

PubMed

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

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

2011-03-10

116

The Dynamics of Plant Cell-Wall Polysaccharide Decomposition in Leaf-Cutting Ant Fungus Gardens  

PubMed Central

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.

Harholt, Jesper; Willats, William G. T.; Boomsma, Jacobus J.

2011-01-01

117

Dynamics of microbial communities during decomposition of litter from pioneering plants in initial soil ecosystems  

NASA Astrophysics Data System (ADS)

In initial ecosystems concentrations of all macro- and micronutrients can be considered as extremely low. Plant litter therefore strongly influences the development of a degraders' food web and is an important source for C and N input into soil in such ecosystems. In the present study, a 13C litter decomposition field experiment was performed for 30 weeks in initial soils from a post-mining area near the city of Cottbus (Germany). Two of this regions' dominant but contrasting pioneering plant species (Lotus corniculatus L. and Calamagrostis epigejos L.) were chosen to investigate the effects of litter quality on the litter decomposing microbial food web in initially nutrient-poor substrates. The results clearly indicate the importance of litter quality, mainly the amount of N stored in the litter material and its bioavailability for the degradation process and the development of microbial communities in the detritusphere and bulk soil. Whereas the degradation process of the L. corniculatus litter which had a low C/N ratio was fast and most pronounced changes in the microbial community structure were observed 1-4 weeks after litter addition, the degradation of the C. epigejos litter material was slow and microbial community changes mainly occurred at between 4 and 30 weeks after litter addition to the soil. However for both litter materials a clear indication for the importance of fungi for the degradation process was observed both on the abundance level as well as on the level of 13C incorporation (activity).

Esperschütz, J.; Zimmermann, C.; Dümig, A.; Welzl, G.; Buegger, F.; Elmer, M.; Munch, J. C.; Schloter, M.

2012-10-01

118

Decomposition behavior of hemicellulose and lignin in the step-change flow rate liquid hot water.  

PubMed

Hemicellulose and lignin are the main factors limiting accessibility of hydrolytic enzymes besides the crystallinity of cellulose. The decomposition behavior of hemicellulose and lignin in the step-change flow rate hot water system was investigated. Xylan removal increased from 64.53% for batch system (solid concentration 4.25% w/v, 18 min, 184°C) to 83.78% at high flow rates of 30 ml/min for 8 min, and then 10 ml/min for 10 min. Most of them (80-90%) were recovered as oligosaccharide. It was hypothesized that the flowing water could enhance the mass transfer to improve the sugars recovery. In addition, the solubilization mechanism of lignin in the liquid hot water was proposed according to the results of Fourier transform-infrared spectroscopy and scanning electron microscopy of the water-insoluble fraction and gas chromatography-mass spectrometry of the water-soluble fraction. It was proposed that lignin in the liquid hot water first migrated out of the cell wall in the form of molten bodies, and then flushed out of the reactor. A small quantity of them was further degraded into monomeric products such as vanillin, syringe aldehyde, coniferyl aldehyde, ferulic acid, and p-hydroxy-cinnamic acid. All of these observations would provide important information for the downstream processing, such as purification and concentration of sugars and the enzymatic digestion of residual solid. PMID:22270547

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

2012-01-22

119

Effects of natural water constituents on the photo-decomposition of methylmercury and the role of hydroxyl radical.  

PubMed

Photo-decomposition of methylmercury (MeHg) in surface water is thought to be an important process that reduces the bioavailability of mercury (Hg) to aquatic organisms. In this study, photo-initiated decomposition of MeHg was investigated under UVA irradiation in the presence of natural water constituents including NO3(-), Fe(3+), and HCO3(-) ions, and dissolved organic matter such as humic and fulvic acid. MeHg degradation followed the pseudo-first-order kinetics; the rate constant increased with increasing UVA intensity (0.3 to 3.0 mW cm(-2)). In the presence of NO3(-), Fe(3+), and fulvic acid, the decomposition rate of MeHg increased significantly due to photosensitization by reactive species such as hydroxyl radical. The presence of humic acid and HCO3(-) ions lowered the degradation rate through a radical scavenging effect. Increasing the pH of the solution increased the degradation rate constant by enhancing the generation of hydroxyl radicals. Hydroxyl radicals play an important role in the photo-decomposition of MeHg in water, and natural constituents in water can affect the photo-decomposition of MeHg by changing radical production and inhibition. PMID:23416204

Kim, Moon-Kyung; Zoh, Kyung-Duk

2013-02-13

120

Phase transition and chemical decomposition of hydrogen peroxide and its water mixtures under high pressures  

NASA Astrophysics Data System (ADS)

We have studied the pressure-induced phase transition and chemical decomposition of hydrogen peroxide and its mixtures with water to 50 GPa, using confocal micro-Raman and synchrotron x-ray diffractions. The x-ray results indicate that pure hydrogen peroxide crystallizes into a tetragonal structure (P41212), the same structure previously found in 82.7% H2O2 at high pressures and in pure H2O2 at low temperatures. The tetragonal phase (H2O2-I) is stable to 15 GPa, above which transforms into an orthorhombic structure (H2O2-II) over a relatively large pressure range between 13 and 18 GPa. Inferring from the splitting of the ?s(O-O) stretching mode, the phase I-to-II transition pressure decreases in diluted H2O2 to around 7 GPa for the 41.7% H2O2 and 3 GPa for the 9.5%. Above 18 GPa H2O2-II gradually decomposes to a mixture of H2O and O2, which completes at around 40 GPa for pure and 45 GPa for the 9.5% H2O2. Upon pressure unloading, H2O2 also decomposes to H2O and O2 mixtures across the melts, occurring at 2.5 GPa for pure and 1.5 GPa for the 9.5% mixture. At H2O2 concentrations below 20%, decomposed mixtures form oxygen hydrate clathrates at around 0.8 GPa-just after H2O melts. The compression data of pure H2O2 and the stability data of the mixtures seem to indicate that the high-pressure decomposition is likely due to the pressure-induced densification, whereas the low-pressure decomposition is related to the heterogeneous nucleation process associated with H2O2 melting.

Chen, Jing-Yin; Kim, Minseob; Yoo, Choong-Shik; Dattelbaum, Dana M.; Sheffield, Stephen

2010-06-01

121

Water Needs of Landscape Plants  

Microsoft Academic Search

Following years of below-average rainfall and very low snowmelt runoff in California, landscape managers, maintenance gardeners, and homeowners in most areas of California are now facing mandatory or voluntary water conservation targets. Water purveyors, local governments, landscape architects, and landscape management professionals are adopting the use of reference evapotranspiration (ETo) estimates to determine precise landscape water budgets and irrigation schedules.

Dennis Pittenger; Mike Henry; David Shaw

122

Effects of nitrogen and phosphorus availability on the decomposition of aquatic plants  

Microsoft Academic Search

The responses of decomposition to nitrogen (N) and phosphorus (P) supply were investigated in three leaf species: Eichhornia crassipes, Vallisneria natans, and Potamogeton maackianus. Decomposition was fastest in E. crassipes (0.047–0.099day?1), intermediate in V. natans (about 0.030day?1), and slowest in P. maackianus (about 0.010day?1). Increase in P-availability increased the decomposition rate of E. crassipes by 68–87%, whereas the impact of

Yonghong Xie; Dan Yu; Bo Ren

2004-01-01

123

Plant traits and decomposition: are the relationships for roots comparable to those for leaves?  

PubMed Central

Background and Aims Fine root decomposition is an important determinant of nutrient and carbon cycling in grasslands; however, little is known about the factors controlling root decomposition among species. Our aim was to investigate whether interspecific variation in the potential decomposition rate of fine roots could be accounted for by root chemical and morphological traits, life history and taxonomic affiliation. We also investigated the co-ordinated variation in root and leaf traits and potential decomposition rates. Methods We analysed potential decomposition rates and the chemical and morphological traits of fine roots on 18 Mediterranean herbaceous species grown in controlled conditions. The results were compared with those obtained for leaves in a previous study conducted on similar species. Key Results Differences in the potential decomposition rates of fine roots between species were accounted for by root chemical composition, but not by morphological traits. The root potential decomposition rate varied with taxonomy, but not with life history. Poaceae, with high cellulose concentration and low concentrations of soluble compounds and phosphorus, decomposed more slowly than Asteraceae and Fabaceae. Patterns of root traits, including decomposition rate, mirrored those of leaf traits, resulting in a similar species clustering. Conclusions The highly co-ordinated variation of roots and leaves in terms of traits and potential decomposition rate suggests that changes in the functional composition of communities in response to anthropogenic changes will strongly affect biogeochemical cycles at the ecosystem level.

Birouste, Marine; Kazakou, Elena; Blanchard, Alain; Roumet, Catherine

2012-01-01

124

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

SciTech Connect

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.

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

2007-03-01

125

Tomato plant-water uptake and plant-water relationships under saline growth conditions  

Microsoft Academic Search

Growth and water uptake both decreases when tomato plants are irrigated with saline water. To determine the relative contribution of physiological traits to these decreases plant fresh and dry weight, leaf area, leaf water (?w) and osmotic (??) potentials, gas exchange parameters, stomatal density, leaf chlorophyll and Na content were investigated in the tomato (Lycopersicon esculentum) cultivars, Daniela and Moneymaker.

R Romero-Aranda; T Soria; J Cuartero

2001-01-01

126

Decomposition of polyurethane in a garbage landfill leakage water and by soil microorganisms  

Microsoft Academic Search

The decomposition of polyurethane, measured gravimetrially or using infrared spectrophotometry, was found to be more complete in polyurethane based on polyester and only very small in polyurethane based on polyether. In the presence of clay minerals the decomposition was inhibited. If positive, the decomposition of polyurethane followed the sequence: remaining free isocyanates?urea and amide groups?urethane groups?isocyanuric acid rings.

Z. Filip

1978-01-01

127

Internal Water Status of Plants.  

National Technical Information Service (NTIS)

Sorghum (Sorghum bicolor (L.) Moench) is a crop known for its ability to persist under heat and moisture stress and often to make productive economic recovery once stresses are alleviated. The mechanisms permitting sorghum and other plants to exist under ...

J. D. Eastin C. Y. Sullivan E. J. Kinbacher

1969-01-01

128

An experimental comparison of chemical traits and litter decomposition rates in a diverse range of subarctic bryophyte, lichen and vascular plant species  

Microsoft Academic Search

P1. Climate change in the subarctic is expected to influence vegetation composition, specifically bryophyte and lichen communities, thereby modifying litter decomposition rates and carbon (C) dynamics of these systems with possible feedbacks to climate. 2. In a 2-year experiment, we investigated decomposition rates and chemical traits of 27 bryophytes, 17 lichens and 5 vascular plants in litter beds in subarctic

Simone I. Lang; Johannes H. C. Cornelissen; Thorsten Klahn; Richard S. P. van Logtestijn; Rob Broekman; Wenka Schweikert; Rien Aerts

2009-01-01

129

EVAPOTRANSPIRATION, CANOPY TEMPERATURE, AND PLANT WATER RELATIONS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Because elevated concentrations of CO2 cause partial stomatal closure, transpiration from plant leaves is reduced, which has many ramifications for plant water relations. First, the reduction in leaf transpiration reduces evaporative cooling with a consequential rise in canopy temperatures. Increa...

130

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

NASA Astrophysics Data System (ADS)

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.

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

131

Spinodal decomposition of a three-component water-in-oil microemulsion system  

SciTech Connect

We have performed a series of spinodal decomposition measurements of a three-component microemulsion system made of a surfactant Aerosol OT, water, and decane. The measurements were made by a temperature jump from a one-phase droplet microemulsion to a two-phase droplet microemulsion along the critical isovolume fraction line (10%) using a time resolved light scattering intensity measurement technique. All three stages of the evolution were studied. Time evolution of intensities for the initial stage follows closely the linearized theory. On the other hand, time evolution of the characteristic wave vector, the maximum scattering intensity, and the intensity distributions in the intermediate and late stages are in good agreement with recent dynamic scaling theories.

Mallamace, F.; Micali, N.; Trusso, S.; Chen, S.H. [Department of Physics, University of Messina, Vill. S. Agata, C.P. 55, 98166 Messina (Italy)]|[Institute of Spectroscopic Techniques, Consiglio Nazionale delle Ricerche, Vill. S. Agata, Salita Sperone 31, 98166 Messina (Italy)]|[Department of Nuclear Engineering, 24-209, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

1995-06-01

132

Effects of enhanced ultraviolet-B radiation on plant nutrients and decomposition of spring wheat under field conditions  

Microsoft Academic Search

Spring wheat (Triticum aestivum) was grown in the field under ambient and supplemental levels of ultraviolet-B (UV-B, 280–315 nm) radiation to determine the potential for alteration in plant nutrients, decomposition, leaf quality and dry matter yield. Supplemental UV-B radiation simulating a 12, 20 and 25% stratospheric ozone depletion significantly decreased dry matter yield, but had no significant impact on harvest

Ming Yue; Yuan Li; Xunling Wang

1998-01-01

133

Experimental Treatment of Lake Erie Water, Erie, Pennsylvania, Water Plant.  

National Technical Information Service (NTIS)

The study resulted from a discussion with representatives of the Bureau of Water for Erie, PA., concerning various possible approaches for expansion of their municipal water plants. The study was designed to check the influence of high-rate and dual-media...

K. A. Dostal G. G. Robeck

1966-01-01

134

Seasonal colonization and decomposition of rat carrion in water and on land in an open field in South Carolina.  

PubMed

Decomposition and insect colonization of rat, Rattus rattus L., carrion on land and in water were compared during summer and winter in a plowed field in northwestern South Carolina. During winter, carcasses on land reached the dried-remains stage of decomposition, whereas carcasses in water reached the early-floating stage. During summer, carcasses in both habitats entered the final-remains stage of decomposition in 1-2 wk. Fewer than 30 species of carrion insects were recorded from the carcasses over the duration of the study, probably reflecting the small size of the carcasses and the depauperate fauna of the habitat. Three species of blow flies--Cynomyopsis cadaverina (Robineau-Desvoidy), Calliphora vicina Robineau-Desvoidy, and Lucilia illustris (Meigen)--colonized carrion on land during winter, but no insects colonized carrion in water during winter. Two species of blow flies, Cochliomyia macellaria (F.) and Phaenicia sericata (Meigen), and 1 species of flesh fly, Sarcophaga bullata Parker, colonized the carrion on land and in water during summer; the blow fly, Phormia regina (Meigen), colonized only the carrion on land. This study demonstrated seasonal variation in decomposition and colonization patterns of carrion in contrasting habitats, with important implications for forensic entomology. PMID:9775597

Tomberlin, J K; Adler, P H

1998-09-01

135

A graph decomposition-based approach for water distribution network optimization  

NASA Astrophysics Data System (ADS)

A novel optimization approach for water distribution network design is proposed in this paper. Using graph theory algorithms, a full water network is first decomposed into different subnetworks based on the connectivity of the network's components. The original whole network is simplified to a directed augmented tree, in which the subnetworks are substituted by augmented nodes and directed links are created to connect them. Differential evolution (DE) is then employed to optimize each subnetwork based on the sequence specified by the assigned directed links in the augmented tree. Rather than optimizing the original network as a whole, the subnetworks are sequentially optimized by the DE algorithm. A solution choice table is established for each subnetwork (except for the subnetwork that includes a supply node) and the optimal solution of the original whole network is finally obtained by use of the solution choice tables. Furthermore, a preconditioning algorithm is applied to the subnetworks to produce an approximately optimal solution for the original whole network. This solution specifies promising regions for the final optimization algorithm to further optimize the subnetworks. Five water network case studies are used to demonstrate the effectiveness of the proposed optimization method. A standard DE algorithm (SDE) and a genetic algorithm (GA) are applied to each case study without network decomposition to enable a comparison with the proposed method. The results show that the proposed method consistently outperforms the SDE and GA (both with tuned parameters) in terms of both the solution quality and efficiency.

Zheng, Feifei; Simpson, Angus R.; Zecchin, Aaron C.; Deuerlein, Jochen W.

2013-04-01

136

Continuous monitoring of plant water potential.  

PubMed

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

Schaefer, N L; Trickett, E S; Ceresa, A; Barrs, H D

1986-05-01

137

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

ScienceCinema

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.

138

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

Microsoft Academic Search

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

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

2011-01-01

139

Water permeability of plant cuticles  

Microsoft Academic Search

Using the system vapor\\/membrane\\/liquid, permeability coefficients of cuticular transpiration (Pct) were determined as functions of water activity in the vapor (awv). Enzymatically isolated cuticular membranes (CM) of Citrus aurantium L. and nonisolated CM of onion bulb scales and eggplant fruits were investigated. Pct of Citrus and eggplant CM decreased with decreasing awv, while permeability coefficients of CM of onion were

J. Schönherr; H. W. Schmidt

1979-01-01

140

Plant growth with limited water.  

National Technical Information Service (NTIS)

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 c...

1991-01-01

141

Formation and decomposition of hydrogen peroxide during UV-radiation, ozonization, and O 3 \\/UV treatment of river water  

Microsoft Academic Search

We have studied the kinetics of the formation of hydrogen peroxide during UV-radiation, ozonization, and O3\\/UV treatment of water of the Dnieper River and model solutions of fulvic acids. We have also investigated decomposition of\\u000a added hydrogen peroxide at the indicated methods of treating river and model waters and the impact of H2O2 on the concentration of dissolved ozone.

V. V. Goncharuk; V. F. Vakulenko; Yu. O. Shvadchina; A. N. Sova; T. N. Sitnichenko; I. E. Kalinichenko

2008-01-01

142

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...

143

Study of the photocatalytic decomposition of water vapor over a NiO-SrTiO/sub 3/ catalyst  

SciTech Connect

Photocatalytic decomposition of H/sub 2/O vapor (and liquid) on SrTiO/sub 3/ powder impregnated with NiO was studied by using a closed gas circulation system and infrared spectroscopy. The activity for the photodecomposition of H/sub 2/O was increased by the pretreatments of reduction of the catalyst by hydrogen, and reoxidation by oxygen before the reaction. The dependence of H/sub 2/O decomposition upon H/sub 2/O vapor pressure indicated that an adsorbed water molecule is necessary for the evolutions of H/sub 2/ and O/sub 2/. A plausible mechanism of photocatalytic decomposition of H/sub 2/O vapor is proposed. 7 figures, 1 table.

Domen, K. (Univ. of Tokyo, Japan); Naito, S.; Onishi, T.; Tamaru, K.; Soma, M.

1982-09-02

144

Water vulnerabilities for existing coal-fired power plants  

Microsoft Academic Search

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

D. Elcock; J. Kuiper

2010-01-01

145

Optimal reliable design and operation of water distribution systems through decomposition  

NASA Astrophysics Data System (ADS)

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.

Ostfeld, Avi

2012-10-01

146

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...

147

2. Water treatment plant entrance, view to W Fort ...  

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

2. Water treatment plant entrance, view to W - Fort Benton Water Treatment Plant, Filtration Plant, Lots 9-13 of Block 7, Fort Benton Original Townsite at Missouri River, Fort Benton, Chouteau County, MT

148

8. Water treatment plant, view to SE, berm in foreground ...  

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

8. Water treatment plant, view to SE, berm in foreground covering settling tank - Fort Benton Water Treatment Plant, Filtration Plant, Lots 9-13 of Block 7, Fort Benton Original Townsite at Missouri River, Fort Benton, Chouteau County, MT

149

3. Water treatment plant, view to W, detail of door ...  

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

3. Water treatment plant, view to W, detail of door area - Fort Benton Water Treatment Plant, Filtration Plant, Lots 9-13 of Block 7, Fort Benton Original Townsite at Missouri River, Fort Benton, Chouteau County, MT

150

10. Water treatment plant, view to S. 1965 addition is ...  

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

10. Water treatment plant, view to S. 1965 addition is in the foreground - Fort Benton Water Treatment Plant, Filtration Plant, Lots 9-13 of Block 7, Fort Benton Original Townsite at Missouri River, Fort Benton, Chouteau County, MT

151

13. Water treatment plant interior view of tanks in control ...  

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

13. Water treatment plant interior view of tanks in control room. View to SW - Fort Benton Water Treatment Plant, Filtration Plant, Lots 9-13 of Block 7, Fort Benton Original Townsite at Missouri River, Fort Benton, Chouteau County, MT

152

4. Water treatment plant, view to NW, berm in foreground ...  

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

4. Water treatment plant, view to NW, berm in foreground - Fort Benton Water Treatment Plant, Filtration Plant, Lots 9-13 of Block 7, Fort Benton Original Townsite at Missouri River, Fort Benton, Chouteau County, MT

153

14. Water treatment plant interior view of chlorination room. View ...  

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

14. Water treatment plant interior view of chlorination room. View to N - Fort Benton Water Treatment Plant, Filtration Plant, Lots 9-13 of Block 7, Fort Benton Original Townsite at Missouri River, Fort Benton, Chouteau County, MT

154

7. Water treatment plant, view to E, berm in foreground ...  

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

7. Water treatment plant, view to E, berm in foreground covering settling tank - Fort Benton Water Treatment Plant, Filtration Plant, Lots 9-13 of Block 7, Fort Benton Original Townsite at Missouri River, Fort Benton, Chouteau County, MT

155

6. Water treatment plant, view NE, berm in foreground ...  

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

6. Water treatment plant, view NE, berm in foreground - Fort Benton Water Treatment Plant, Filtration Plant, Lots 9-13 of Block 7, Fort Benton Original Townsite at Missouri River, Fort Benton, Chouteau County, MT

156

5. Water treatment plant, view to N, berm in foreground ...  

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

5. Water treatment plant, view to N, berm in foreground - Fort Benton Water Treatment Plant, Filtration Plant, Lots 9-13 of Block 7, Fort Benton Original Townsite at Missouri River, Fort Benton, Chouteau County, MT

157

Thiocyanate decomposition under aerobic and oxygen-free conditions by the aboriginal bacterial community isolated from the waste water of a metallurgical works  

Microsoft Academic Search

A mesophilic alkalitolerant aboriginal bacterial community capable of autotrophic thiocyanate decomposition under aerobic\\u000a and oxygen-free conditions was isolated from reused water of a metallurgical works. The growth of the aboriginal bacterial\\u000a community was optimal at pH 9.0. Ammonium and sulfate were the end products of thiocyanate decomposition under both aerobic\\u000a and oxygen-free conditions. Under oxygen-free conditions, thiocyanate decomposition occurred in

N. V. Grigor’eva; Yu. V. Smirnova; L. E. Dulov

2009-01-01

158

Layerwise decomposition of water dynamics in reverse micelles: A simulation study of two-dimensional infrared spectrum  

NASA Astrophysics Data System (ADS)

We present computer simulation study of two-dimensional infrared spectroscopy (2D-IR) of water confined in reverse micelles (RMs) of various sizes. The present study is motivated by the need to understand the altered dynamics of confined water by performing layerwise decomposition of water, with an aim to quantify the relative contributions of different layers water molecules to the calculated 2D-IR spectrum. The 0-1 transition spectra clearly show substantial elongation, due to inhomogeneous broadening and incomplete spectral diffusion, along the diagonal in the surface water layer of different sized RMs. Fitting of the frequency fluctuation correlation functions reveal that the motion of the surface water molecules is sub-diffusive and indicate the constrained nature of their dynamics. This is further supported by two peak nature of the angular analogue of van Hove correlation function. With increasing system size, the water molecules become more diffusive in nature and spectral diffusion almost completes in the central layer of the larger size RMs. Comparisons between experiments and simulations establish the correspondence between the spectral decomposition available in experiments with the spatial decomposition available in simulations. Simulations also allow a quantitative exploration of the relative role of water, sodium ions, and sulfonate head groups in vibrational dephasing. Interestingly, the negative cross correlation between force on oxygen and hydrogen of O-H bond in bulk water significantly decreases in the surface layer of each RM. This negative cross correlation gradually increases in the central water pool with increasing RMs size and this is found to be partly responsible for the faster relaxation rate of water in the central pool.

Biswas, Rajib; Furtado, Jonathan; Bagchi, Biman

2013-10-01

159

Layerwise decomposition of water dynamics in reverse micelles: A simulation study of two-dimensional infrared spectrum.  

PubMed

We present computer simulation study of two-dimensional infrared spectroscopy (2D-IR) of water confined in reverse micelles (RMs) of various sizes. The present study is motivated by the need to understand the altered dynamics of confined water by performing layerwise decomposition of water, with an aim to quantify the relative contributions of different layers water molecules to the calculated 2D-IR spectrum. The 0-1 transition spectra clearly show substantial elongation, due to inhomogeneous broadening and incomplete spectral diffusion, along the diagonal in the surface water layer of different sized RMs. Fitting of the frequency fluctuation correlation functions reveal that the motion of the surface water molecules is sub-diffusive and indicate the constrained nature of their dynamics. This is further supported by two peak nature of the angular analogue of van Hove correlation function. With increasing system size, the water molecules become more diffusive in nature and spectral diffusion almost completes in the central layer of the larger size RMs. Comparisons between experiments and simulations establish the correspondence between the spectral decomposition available in experiments with the spatial decomposition available in simulations. Simulations also allow a quantitative exploration of the relative role of water, sodium ions, and sulfonate head groups in vibrational dephasing. Interestingly, the negative cross correlation between force on oxygen and hydrogen of O-H bond in bulk water significantly decreases in the surface layer of each RM. This negative cross correlation gradually increases in the central water pool with increasing RMs size and this is found to be partly responsible for the faster relaxation rate of water in the central pool. PMID:24116645

Biswas, Rajib; Furtado, Jonathan; Bagchi, Biman

2013-10-14

160

Heavy water physical verification in power plants  

SciTech Connect

This paper is a report on the Agency experience in verifying heavy water inventories in power plants. The safeguards objectives and goals for such activities are defined in the paper. The heavy water is stratified according to the flow within the power plant, including upgraders. A safeguards scheme based on a combination of records auditing, comparing records and reports, and physical verification has been developed. This scheme has elevated the status of heavy water safeguards to a level comparable to nuclear material safeguards in bulk facilities. It leads to attribute and variable verification of the heavy water inventory in the different system components and in the store. The verification methods include volume and weight determination, sampling and analysis, non-destructive assay (NDA), and criticality check. The analysis of the different measurement methods and their limits of accuracy are discussed in the paper.

Morsy, S.; Schuricht, V.; Beetle, T.; Szabo, E.

1986-01-01

161

Nitrogen Addition Reduces Decomposition of Native Recalcitrant Soil Carbon Under Plants With High Root Lignin and Low Cell Soluble Content  

NASA Astrophysics Data System (ADS)

The effect of increased atmospheric nitrogen (N) deposition on long-term soil carbon (C) storage remains unclear. Both enhanced and retarded decomposition of lignin and other recalcitrant C substrates in the soil have been reported with N addition. We examined the effect of N addition on soil C pools under 12 different grassland species planted as monoculture plots treated with 560 ppm atmospheric CO2 concentrations, and 0 and 4 g N fertilizer m-2 yr-1 in Minnesota, USA. After 5 years of treatment we separated soil C into light and heavy fractions and used the distinct 13C isotopic signature of C3 plants in elevated CO2 plots to separate the more recalcitrant native or pre-treatment C from newly formed C. As fertilizer N was labeled with 15N, we also calculated the amount of N fertilizer retained in the soil. Nitrogen addition significantly increased the pre-treatment C pool of the light soil fraction by 18% compared to plots receiving no N addition, suggesting reduced decomposition of C with added N. Added N did not affect the more stable heavy soil C fraction. In plots with added N, the pre-treatment C pool of the light fraction was especially high for plants that produced roots high in lignin and low in cell soluble content. These results suggest that high lignin content interacted with high levels of N to stimulate chemical stabilization of native soil C. The amount of fertilizer N retained in the light fraction was significantly positively related to pre-treatment soil C content, further evidence that N fertilization promoted stabilization of pre-treatment C. We conclude that plant species composition (via its effects on root lignin concentrations) determines the influence of atmospheric N deposition on the decomposition of soil organic matter under elevated CO2.

Dijkstra, F. A.; Hobbie, S. E.; Knops, J. M.; Reich, P. B.

2003-12-01

162

regulating plant water status by stomatal control  

Microsoft Academic Search

The regulation of gas exchange at the leaf level is a key factor for plant survival under a fluctuating environment (Buckley,\\u000a 2005). In this context, control of stomatal opening and closure is the evolutionary solution to balance water loss with CO2 uptake and yield. A decrease in leaf\\/root water potential resulting from soil drought is typically accompanied by an elevated

Laury Chaerle; DOMINIQUE VAN DER STRAETEN

163

Streambank plants vital to water quality  

SciTech Connect

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.

Sherman, H.

1989-08-01

164

Kinetics of electron-induced decomposition of CF2Cl2 coadsorbed with water (ice): a comparison with CCl4.  

PubMed

The kinetics of decomposition and subsequent chemistry of adsorbed CF(2)Cl(2), activated by low-energy electron irradiation, have been examined and compared with CCl(4). These molecules have been adsorbed alone and coadsorbed with water ice films of different thicknesses on metal surfaces (Ru; Au) at low temperatures (25 K; 100 K). The studies have been performed with temperature programmed desorption (TPD), reflection absorption infrared spectroscopy (RAIRS), and x-ray photoelectron spectroscopy (XPS). TPD data reveal the efficient decomposition of both halocarbon molecules under electron bombardment, which proceeds via dissociative electron attachment (DEA) of low-energy secondary electrons. The rates of CF(2)Cl(2) and CCl(4) dissociation increase in an H(2)O (D(2)O) environment (2-3x), but the increase is smaller than that reported in recent literature. The highest initial cross sections for halocarbon decomposition coadsorbed with H(2)O, using 180 eV incident electrons, are measured (using TPD) to be 1.0+/-0.2 x 10(-15) cm(2) for CF(2)Cl(2) and 2.5+/-0.2 x 10(-15) cm(2) for CCl(4). RAIRS and XPS studies confirm the decomposition of halocarbon molecules codeposited with water molecules, and provide insights into the irradiation products. Electron-induced generation of Cl(-) and F(-) anions in the halocarbon/water films and production of H(3)O(+), CO(2), and intermediate compounds COF(2) (for CF(2)Cl(2)) and COCl(2), C(2)Cl(4) (for CCl(4)) under electron irradiation have been detected using XPS, TPD, and RAIRS. The products and the decomposition kinetics are similar to those observed in our recent experiments involving x-ray photons as the source of ionizing irradiation. PMID:15511180

Faradzhev, N S; Perry, C C; Kusmierek, D O; Fairbrother, D H; Madey, T E

2004-11-01

165

Labile compounds in plant litter reduce the sensitivity of decomposition to warming and altered precipitation.  

PubMed

Together, climate and litter quality strongly regulate decomposition rates. Although 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 3 yr, we studied the effects of warming and altered precipitation on mass loss and compound-specific decomposition using two litter types that possessed similar heteropolymer chemistry, but different proportions of labile and recalcitrant compounds. Climate treatments immediately affected the mass loss of the more recalcitrant litter, but affected the more labile litter only after 2 yr. After 3 yr, although both litter types had lost similar amounts of mass, warming (c. 4°C) and supplemental precipitation (150% of ambient) together accelerated the 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. Our finding that labile compounds in litter reduce the climate sensitivity of mass loss and the decomposition of recalcitrant matrix is novel. Our results highlight the potential for litter quality to regulate the effect of climatic changes on the sequestration of litter-derived carbon. PMID:23822593

Suseela, Vidya; Tharayil, Nishanth; Xing, Baoshan; Dukes, Jeffrey S

2013-07-04

166

Microbiological quality of drinking water at eight water treatment plants.  

PubMed

Eight drinking water treatment plants were sampled monthly during one year to evaluate the removal of bacterial indicators, new indicators and some pathogenic bacteria. Six plants are allocated along the Nile River at Cairo segment and the two others on Ismailia Canal. In this study many parameters were determined; the classical bacterial indicators (total bacterial counts at 22 and 37 degrees C, total coliforms, faecal coliforms and faecal streptococci) show the same trend in all plant intakes except faecal streptococci parameter. The numbers of faecal streptococci in plant intakes on the main stream of Nile River ranged from 8 to 250 MPN/100 ml, but the others ranged from 80 to 2700 MPN/100 ml. With regard to new indicators; total yeasts, Candida albicans, Aeromonas hydrophlia and total staphylococci ranged from 10(1) to 10(5), 10(2) to 10(5), 10(2) to 10(5) and 10(2) to 10(3) cfu/100 ml, respectively. In case of pathogens, salmonellae ranged between 10(2) and 10(3) cfu/100 ml, total vibrios varied between 10(2) and 10(4) and the Listeria group ranged from 10(2) to 10(5) cfu/100 ml from the intake samples. All tested samples from the outlet of water treatment plants, which produce drinking water, were free of classical bacterial indicators. So the produced water has a good quality from the bacteriological point, according to national and international regulations. On the other hand, the drinking water from some tested plants had one or more positive parameters of new indicators and pathogenic bacteria. PMID:11798415

El-Taweel, G E; Shaban, A M

2001-11-01

167

Experimental burial inhibits methanogenesis and anaerobic decomposition in water-saturated peats.  

PubMed

A mechanistic understanding of carbon (C) sequestration and methane (CH(4)) production is of great interest due to the importance of these processes for the global C budget. Here we demonstrate experimentally, by means of column experiments, that burial of water saturated, anoxic bog peat leads to inactivation of anaerobic respiration and methanogenesis. This effect can be related to the slowness of diffusive transport of solutes and evolving energetic constraints on anaerobic respiration. Burial lowered decomposition constants in homogenized peat sand mixtures from about 10(-5) to 10(-7) yr(-1), which is considerably slower than previously assumed, and methanogenesis slowed down in a similar manner. The latter effect could be related to acetoclastic methanogenesis approaching a minimum energy quantum of -25 kJ mol(-1) (CH(4)). Given the robustness of hydraulic properties that locate the oxic-anoxic boundary near the peatland surface and constrain solute transport deeper into the peat, this effect has likely been critical for building the peatland C store and will continue supporting long-term C sequestration in northern peatlands even under moderately changing climatic conditions. PMID:21958021

Blodau, Christian; Siems, Melanie; Beer, Julia

2011-11-02

168

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...

169

Preliminary treatment of dairy plant waste water  

Microsoft Academic Search

The quality of a dairy plant wastewater that had been discharged in a ditch and then into a small stream was evaluated over a three?year period. The wastewater was released to the ditch, where after traversing a distance of approximately 100 meters, it entered a snail moving stream of water. Vegetation in the ditch served as a biofilter for the

R. H. Gough; P. McGrew

1993-01-01

170

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...

171

Decomposition of 13C-labelled standard plant material in a latitudinal transect of European coniferous forests: Differential impact of climate on the decomposition of soil organic matter compartments  

Microsoft Academic Search

13C labelled plant material was incubated in situ over 2 to 3 years in 8 conifer forest soils located on acid and limestone parent material along a north-south climatic transect from boreal to dry Mediterranean regions in western Europe. The objectives of the experiment were to evaluate the effects of climate and the soil environment on decomposition and soil organic

Marie-Madeleine Coûteaux; Pierre Bottner; Jonathan M. Anderson; Björn Berg; Thomas Bolger; Pere Casals; Joan Romanyà; Jean M. Thiéry; V. Ramon Vallejo

2001-01-01

172

Mobile water treatment plant special study  

SciTech Connect

Characterization of the level and extent of groundwater contamination in the vicinity of Title I mill sites began during the surface remedial action stage (Phase 1) of the Uranium Mill Tailings Remedial Action (UMTRA) Project. Some of the contamination in the aquifer(s) at the abandoned sites is attributable to milling activities during the years the mills were in operation. To begin implementation of Phase 11 groundwater remediation, the US Department of Energy (DOE) requested that (1) the Technical Assistance Contractor (TAC) conduct a study to provide for the design of a mobile water treatment plant to treat groundwater extracted during site characterization studies at completed Phase I UMTRA sites, and (2) the results of the TAC investigations be documented in a special study report. This special study develops the design criteria for a water treatment plant that can be readily transported from one UMTRA site to another and operated as a complete treatment system. The 1991 study provides the basis for selecting a mobile water treatment system to meet the operating requirements recommended in this special study. The scope of work includes the following: Determining contaminants, flows, and loadings. Setting effluent quality criteria. Sizing water treatment unit(s). Evaluating non-monetary aspects of alternate treatment processes. Comparing costs of alternate treatment processes. Recommending the mobile water treatment plant design criteria.

Not Available

1992-12-01

173

The interaction between decomposition, net N and P mineralization and their mobilization to the surface water in fens.  

PubMed

Worldwide, fens and peat lakes that used to be peat-forming systems have become a significant source of C, N and P due to increased peat decomposition. To test the hypothesis that net nutrient mineralization rates may be uncoupled from decomposition rates, we investigated decomposition and net mineralization rates of nutrients in relation to sediment and pore water characteristics. We incubated 28 non-calcareous peat sediments and floating fen soils under aerobic and anaerobic conditions. We also tried to find a simple indicator to estimate the potential nutrient mobilization rates from peat sediments to the water layer by studying their relation with sediment and pore water characteristics in 44 Dutch non-calcareous peat lakes and ditches. Decomposition rates were primarily determined by the organic matter content, and were higher under aerobic conditions. However, highly decomposed peat sediments with low C:P and C:N ratios still showed high net nutrient mineralization rates. At Fe:PO(4) ratios below 1molmol(-1), PO(4) mobilization from the sediment to the water layer was considerable and linearly related to the pore water PO(4) concentration. At higher ratios, there was a strong linear correlation between the Fe:PO(4) ratio and PO(4) mobilization. Hence, measuring Fe and PO(4) in anaerobic sediment pore water provides a powerful tool for a quick assessment of internal PO(4) fluxes. Mobilization of mineral N was largely determined by diffusion. Total sediment Fe:S ratios gave an important indication of the amount of Fe that is available to immobilize PO(4). Pore water Fe concentrations decreased at ratios <1molmol(-1), whereas pore water PO(4) concentrations and PO(4) mobilization to the water layer increased. As PO(4) mobilization rates from the sediment to the water layer contribute to almost half of the total P load in Dutch peat lakes and fens, it is of pivotal importance to examine the magnitude of internal fluxes. Dredging of the nutrient-rich upper sediment layer will only be a useful restoration measure if both the influx of P-rich water and its internal mobilization from the newly exposed, potentially more reactive peat layer are sufficiently low. PMID:20392472

Geurts, Jeroen J M; Smolders, Alfons J P; Banach, Artur M; van de Graaf, Jan P M; Roelofs, Jan G M; Lamers, Leon P M

2010-03-27

174

Effects of high and low fertility plant species on dead root decomposition and nitrogen mineralisation  

Microsoft Academic Search

The influence of growing grass species Holcus lanatus and Festuca ovina on the decomposition of dead roots of H. lanatus, F. rubra and F. ovina and on the nitrogen (N) mineralisation from these residues was studied in a greenhouse experiment. H. lanatus, F. rubra and F. ovina are typical of soils with high, intermediate and low fertility, respectively. Dead roots

T. A. J van der Krift; P. Gioacchini; P. J. Kuikman; F. Berendse

2001-01-01

175

Sonochemistry of alcohol-water mixtures: Spin-trapping evidence for thermal decomposition and isotope-exchange reactions  

Microsoft Academic Search

The sonochemistry of argon-saturated water-alcohol mixtures has been studied by ESR and spin trapping with 3,5-dibromo-4-nitrosobenzenesulfonate. Free-radical intermediates induced by 50-kHz ultrasound in aqueous solutions of ethanol, 1-propanol, 2-propanol, and 2-methyl-2-propanol were identified. Spin adducts typical of thermal decomposition of the alcohols and of H- and OH-induced abstraction reactions were observed. In the sonolysis of mixed-isotope systems of the type

C. Murali Krishna; Takashi Kondo; Peter Riesz

1989-01-01

176

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

Microsoft Academic Search

NCEP\\/GFS analysis is used to investigate the scale dependence and the interplay between the terms of the atmospheric water\\u000a budget over West Africa using a dedicated decomposition methodology. The focus is on a 2-month period within the active monsoon\\u000a period of 2006. Results show that the dominant scales of seasonal mean precipitation and moisture flux divergence over West\\u000a Africa during

Soline Bielli; Remy Roca

2010-01-01

177

Atomic decomposition of the protein solvation free energy and its application to amyloid-beta protein in water  

NASA Astrophysics Data System (ADS)

We report the development of an atomic decomposition method of the protein solvation free energy in water, which ascribes global change in the solvation free energy to local changes in protein conformation as well as in hydration structure. So far, empirical decomposition analyses based on simple continuum solvation models have prevailed in the study of protein-protein interactions, protein-ligand interactions, as well as in developing scoring functions for computer-aided drug design. However, the use of continuum solvation model suffers serious drawbacks since it yields the protein free energy landscape which is quite different from that of the explicit solvent model and since it does not properly account for the non-polar hydrophobic effects which play a crucial role in biological processes in water. Herein, we develop an exact and general decomposition method of the solvation free energy that overcomes these hindrances. We then apply this method to elucidate the molecular origin for the solvation free energy change upon the conformational transitions of 42-residue amyloid-beta protein (A?42) in water, whose aggregation has been implicated as a primary cause of Alzheimer's disease. We address why A?42 protein exhibits a great propensity to aggregate when transferred from organic phase to aqueous phase.

Chong, Song-Ho; Ham, Sihyun

2011-07-01

178

Effects of residue quality and climate on plant residue decomposition and nutrient release along the transect from humid forest to Sahel of West Africa  

Microsoft Academic Search

Field litterbag studies were conducted in the 2000 rainy season and the 2000\\/2001 dry season along the transect of West African\\u000a major agroecological zones (agroeco-zones) to measure the decomposition of, and N and P release from 5 plant residues (leaves\\u000a of woody species) with increasing quality: Dactyladenia barteri, Pterocarpus santalinoides, Alchornea cordifolia, Senna siamea and Gliricidia sepium. The decomposition rate constant (wk?1) ranged from

G. Tian; M. A. Badejo; A. I. Okoh; F. Ishida; G. O. Kolawole; Y. Hayashi; F. K. Salako

2007-01-01

179

System analysis of coking plant water  

SciTech Connect

A potentiometric method has been developed to measure the concentration of S/sup 2 -/, CN/sup -/, free NH/sub 3/, HCO/sub 3//sup -/ and organic bases found in coking plant waste water. The method can be performed rapidly. The determination is not hindered by the presence of SCN/sup -/, Cl, SO/sub 4//sup 2 -/, NH/sub 4//sup -/. The method is economical, and requires no sample preparation, expensive or inaccessible reagents, electrodes or instruments and is easily performed under the conditions of the plant laboratory. 19 references, 4 figures, 1 table.

Dyatel, S.G.; Teikhrib, T.K.

1983-01-01

180

Investigation on optimization of conventional drinking water treatment plant  

Microsoft Academic Search

Conventional drinking water treatment plant consists of coagulation, flocculation, sedimentation, and filtration and disinfection units. Depending on water quality influent, each unit can be optimized to achieve the desired water quality effluent, both in design and operation stages. A typical water treatment plant has the combination of processes needed to treat the contaminants in the source water treated by the

I. Piri; I. Homayoonnezhad; P. Amirian

2010-01-01

181

Characteristics, Residue Decomposition, and Carbon Mineralization of Leguminous and Spontaneous Plants in Coffee Systems  

Microsoft Academic Search

We investigated the chemical and biochemical composition, residue decomposition, and mineralization rate of leguminous (Cajanus cajan, Crotalaria spectabilis, and Lablab purpureus) and spontaneous vegetation in two experimental coffee systems in southeast Brazil. The nitrogen (N) content of the shoot biomass varied from 19.3 to 45.7 g kg, and phosphorus (P) content ranged from 1.6 to 3.8 g kg. C. cajan

Eduardo da Silva Matos; Irene Maria Cardoso; Renata Lúcia Souto; Paulo César de Lima; Eduardo de Sá Mendonça

2011-01-01

182

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

SciTech Connect

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.

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

2008-04-01

183

Hydraulic lift and water use by plants: implications for water balance, performance and plant-plant interactions  

Microsoft Academic Search

During drought periods, sugar maple (Acer saccharum) demonstrates “hydraulic lift”; nocturnal uptake of water by roots from deep soil layers that is released from shallow roots into upper soil layers. Using standard water relations methods and stable hydrogen isotope analysis of both source-water and plant-water, I investigated (1) the magnitude and radial extent of hydraulic lift by mature, relatively open-grown

Todd E. Dawson

1993-01-01

184

The Microbial Efficiency-Matrix Stabilization (MEMS) framework integrates plant litter decomposition with soil organic matter stabilization: do labile plant inputs form stable soil organic matter?  

PubMed

The decomposition and transformation of above- and below-ground plant detritus (litter) is the main process by which soil organic matter (SOM) is formed. Yet, research on litter decay and SOM formation has been largely uncoupled, failing to provide an effective nexus between these two fundamental processes for carbon (C) and nitrogen (N) cycling and storage. We present the current understanding of the importance of microbial substrate use efficiency and C and N allocation in controlling the proportion of plant-derived C and N that is incorporated into SOM, and of soil matrix interactions in controlling SOM stabilization. We synthesize this understanding into the Microbial Efficiency-Matrix Stabilization (MEMS) framework. This framework leads to the hypothesis that labile plant constituents are the dominant source of microbial products, relative to input rates, because they are utilized more efficiently by microbes. These microbial products of decomposition would thus become the main precursors of stable SOM by promoting aggregation and through strong chemical bonding to the mineral soil matrix. PMID:23504877

Cotrufo, M Francesca; Wallenstein, Matthew D; Boot, Claudia M; Denef, Karolien; Paul, Eldor

2013-02-05

185

Decomposition of soil and plant carbon from pasture systems after 9 years of exposure to elevated CO2: impact on C cycling and modeling  

Microsoft Academic Search

Elevated atmospheric CO2 may alter decomposition rates through changes in plant material quality and through its impact on soil microbial activity. This study examines whether plant material produced under elevated CO2 decomposes differently from plant material produced under ambient CO2. Moreover, a long-term experiment offered a unique opportunity to evaluate assumptions about C cycling under elevated CO2 made in coupled

Graaff de M. A; Johan Six; David Harris; H. Blums; Chris van Kessel

2004-01-01

186

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

PubMed

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

Poulette, Megan M; Arthur, Mary A

2012-03-01

187

Effect of water vapor on the thermal decomposition process of zinc hydroxide chloride and crystal growth of zinc oxide  

NASA Astrophysics Data System (ADS)

Thermal decomposition process of zinc hydroxide chloride (ZHC), Zn5(OH)8Cl2·H2O, prepared by a hydrothermal slow-cooling method has been investigated by simultaneous X-ray diffractometry and differential scanning calorimetry (XRD-DSC) and thermogravimetric-differential thermal analysis (TG-DTA) in a humidity-controlled atmosphere. ZHC was decomposed to ZnO through ?-Zn(OH)Cl as the intermediate phase, leaving amorphous hydrated ZnCl2. In humid N2 with P=4.5 and 10 kPa, the hydrolysis of residual ZnCl2 was accelerated and the theoretical amount of ZnO was obtained at lower temperatures than in dry N2, whereas significant weight loss was caused by vaporization of residual ZnCl2 in dry N2. ZnO formed by calcinations in a stagnant air atmosphere had the same morphology of the original ZHC crystals and consisted of the c-axis oriented column-like particle arrays. On the other hand, preferred orientation of ZnO was inhibited in the case of calcinations in 100% water vapor. A detailed thermal decomposition process of ZHC and the effect of water vapor on the crystal growth of ZnO are discussed.Graphical abstractThermal decomposition process of zinc hydroxide chloride (ZHC), Zn5(OH)8Cl2·H2O, has been investigated by novel thermal analyses with three different water vapor partial pressures. In the water vapor atmosphere, the formation of ZnO was completed at lower temperatures than in dry.

Kozawa, Takahiro; Onda, Ayumu; Yanagisawa, Kazumichi; Kishi, Akira; Masuda, Yasuaki

2011-03-01

188

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

NASA Astrophysics Data System (ADS)

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\\Ncy 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.

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

189

Litter stoichiometric traits of plant species of high-latitude ecosystems show high responsiveness to global change without causing strong variation in litter decomposition.  

PubMed

• High-latitude ecosystems are important carbon accumulators, mainly as a result of low decomposition rates of litter and soil organic matter. We investigated whether global change impacts on litter decomposition rates are constrained by litter stoichiometry. • Thereto, we investigated the interspecific natural variation in litter stoichiometric traits (LSTs) in high-latitude ecosystems, and compared it with climate change-induced LST variation measured in the Meeting of Litters (MOL) experiment. This experiment includes leaf litters originating from 33 circumpolar and high-altitude global change experiments. Two-year decomposition rates of litters from these experiments were measured earlier in two common litter beds in sub-Arctic Sweden. • Response ratios of LSTs in plants of high-latitude ecosystems in the global change treatments showed a three-fold variation, and this was in the same range as the natural variation among species. However, response ratios of decomposition were about an order of magnitude lower than those of litter carbon/nitrogen ratios. • This implies that litter stoichiometry does not constrain the response of plant litter decomposition to global change. We suggest that responsiveness is rather constrained by the less responsive traits of the Plant Economics Spectrum of litter decomposability, such as lignin and dry matter content and specific leaf area. PMID:22889103

Aerts, R; van Bodegom, P M; Cornelissen, J H C

2012-08-13

190

Assessing the water quality index of water treatment plant and bore wells, in Delhi, India  

Microsoft Academic Search

Water quality monitoring exercise was carried out with water quality index (WQI) method by using water characteristics data\\u000a for bore wells and a water treatment plant in Delhi city from December 2006 to August 2007. The water treatment plant received\\u000a surface water as raw water, and product water is supplied after treatment. The WQI is used to classify water quality

M. K. Chaturvedi; J. K. Bassin

2010-01-01

191

Problems of Terminology in the Teaching of Plant Water Relations  

ERIC Educational Resources Information Center

|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)|

Bradbeer, Philip A.; And Others

1976-01-01

192

Problems of Terminology in the Teaching of Plant Water Relations  

ERIC Educational Resources Information Center

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)

Bradbeer, Philip A.; And Others

1976-01-01

193

WSU-TFREC Orchard Calculator: Estimating Water Use by Plants  

NSDL National Science Digital Library

The Washington State University Tree Fruit Research and Extension Center provides a calculator for estimating water use by plants or pET (potential evapotranspiration). Water use varies widely from plant to plant, so estimates are usually first derived for a single situation, such as grass, and then adapted for other plants. The calculator uses the Penman method to estimate daily pET in inches of water. It requires average daily values of four measurements: sunlight, wind, temperature, and humidity.

1996-05-29

194

Elementary composition, humus composition, and decomposition in soil of charred grassland plants  

Microsoft Academic Search

Charred plant residues collected after the burning of grassland vegetation in which Susuki plants predominated (Eulalia, Miscanthus sinensis A.), were divided into 5 particle size fractions of >2, 1-2, 0.5-1.0, 0.25-0.5, and <0.25 mm using sieves. 1) The percentage distribution of organic matter in the charred plant residues was higher in the larger particle size fractions, and the reverse was

Haruo Shindo

1991-01-01

195

Use of 13C-labelled plant materials and ergosterol, PLFA and NLFA analyses to investigate organic matter decomposition in Antarctic soil  

Microsoft Academic Search

The relationship between organic matter decomposition and changes in microbial community structure were investigated in Antarctic soils using 13C-labelled plant materials. Soils with and without labelled Deschampsia antarctica (a native Antarctic grass) were incubated for 42 days and sampled at 0, 7, 14, 21, 28 and 42 days. Changes in microbial community structure were assessed using phospholipid fatty acid analysis

Elaine Malosso; Lorna English; David W. Hopkins; Anthony G. O'Donnell

2004-01-01

196

11. Water treatment plant interior view of pipes, stairs, and ...  

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

11. Water treatment plant interior view of pipes, stairs, and pump in pump room. View to SW - Fort Benton Water Treatment Plant, Filtration Plant, Lots 9-13 of Block 7, Fort Benton Original Townsite at Missouri River, Fort Benton, Chouteau County, MT

197

12. Water treatment plant interior view of pipes and pump ...  

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

12. Water treatment plant interior view of pipes and pump in heater room. View to W - Fort Benton Water Treatment Plant, Filtration Plant, Lots 9-13 of Block 7, Fort Benton Original Townsite at Missouri River, Fort Benton, Chouteau County, MT

198

Plant water uptake and water use efficiency of greenhouse tomato cultivars irrigated with saline water  

Microsoft Academic Search

Effects of salinity on tomato (Lycopersicon esculentum Mill.) fruit yield, plant water uptake and water use efficiency (WUE) have been quantified in experiments carried out under greenhouse and soil-less cultivation with four cultivars (Floradade, L1, L5 and L9) and four salinity levels (0, 25, 50, and 75mM NaCl). Fruit represented 70% of plant fresh weight while leaves and stems represented

A. Reina-Sánchez; R. Romero-Aranda; J. Cuartero

2005-01-01

199

Response of plants to CO 2 under water limited conditions  

Microsoft Academic Search

The influence of inefeased atmospheric CO2 on the interaction between plant growth and water use is proving to be one of the most profound impacts of the anthropogenic ‘Greenhouse Effect’. This paper illustrates the interaction between CO2 and water in plant growth at a range of scales. Most published work has concentrated on water use efficiency, especially at shorter time

J. I. L. Morison; H. Lambers

1993-01-01

200

Multipathway health risk assessment of power plant water discharges  

Microsoft Academic Search

The chemicals released with water discharges from a fossil-fueled power plant may present health risks through a variety of exposure pathways including ingestion of drinking water, fish consumption and dermal absorption while swimming. The Total Risk of Utility Emissions (TRUE) model provides a framework that allows one to assess the multipathway health risks associated with water discharges from power plants.

C. Seigneur; E. Constantinou; L. Levin

1996-01-01

201

Instrumentation handbook for integrated power plant water management: Final report  

Microsoft Academic Search

Diminishing water resources and stringent environmental regulations are strong motivations for power plants to incorporate well-defined and closely monitoring instruments can greatly aid in this effort. A handbook discussing the primary measuring elements normally used in an integrated water management system has been developed. This handbook includes a section on typical power plant water management systems, as well as separate

M. T. Irani; R. D. Geist; R. Murphy

1988-01-01

202

Metabolic responses of mesophytes to plant water deficits  

Microsoft Academic Search

The metabolic responses of mesophytic plant to dehydration are surveyed and discussed. Whole-plant water relations, variations in COâ, water and solute traffic, photosynthesis, respiration, and nitrogen metabolism are discussed in relation to the experience of water deprivation. The adaptive significance of these metabolic responses is discussed.

A. D. Hanson; W. D. Hitz

1982-01-01

203

Control of Water Environment of Plants using Waste Biomass  

Microsoft Academic Search

This paper describes new methods to plant and grow young crops in arid zones by controlling the water environment of plant using waste biomass. One method is to cover plant leaves by fibrous membrane made of waste paper. Fine fiber coating was made by spraying the starch glue and then dusting the fine paper fibers on the plant leaves. The

Osamu Kitani; Kingshuk Roy; Mizuho Yoshida; Ryosuke Endo

204

Impacts of acid precipitation on decomposition and plant communities in lakes  

Microsoft Academic Search

Over the past few decades the acidity of lakes and rivers has been increasing in several areas of the world. In southern Norway, western Sweden, the Canadian Shield, and the northeastern United States, acidification of fresh waters has become a major environmental problem. It has been clearly established that acid precipitation is the cause of decreasing pH levels in waters

G. R. Hendrey; F. W. Barvenik

1978-01-01

205

Decomposition of prepolymers and molding materials of phenol resin in subcritical and supercritical water under an Ar atmosphere  

SciTech Connect

Seven prepolymers of phenol resin were decomposed into their monomers such as phenol, cresols, and p-isopropylphenol by reactions at 523--703 K under an Ar atmosphere in subcritical and supercritical water. The total yield of identified products depended on the kind of prepolymers, and the maximum yield reached 78% in the reaction at 703 K for 0.5 h. The decomposition reactions were accelerated by the addition of Na{sub 2}CO{sub 3}, and the yields of identified monomers reached more than 90%. Two kinds of molding materials of phenol resin whose content of phenol resin was less than 50% were also decomposed mainly into phenol and cresols by the reaction in supercritical water.

Suzuki, Yuichi; Tagaya, Hideyuki; Kadokawa, Junichi; Chiba, Koji [Yamagata Univ., Yonezawa, Yamagata (Japan). Dept. of Materials Science and Engineering; Asou, Tetsuo [Sumitomo Bakelite Co. Ltd., Fujieda, Shizuoka (Japan)

1999-04-01

206

Influence of process parameters on the hydrothermal decomposition and oxidation of glucose in sub- and supercritical water  

Microsoft Academic Search

Supercritical water oxidation (SCWO) of wet waste biomass for energy recovery could be an advantageous alternative to conventional combustion with preceding drying. Therefore the reactions of glucose as a model substance for cellulosic biomass were investigated in sub- and supercritical water. The results of hydrothermal and oxidative experiments carried out in a continuous high-pressure plant with a feed solution of

D. Klingler; H. Vogel

2010-01-01

207

27. CUSHMAN POWER PLANT NO. 1, WATER CURVE SPILLWAY ...  

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

27. CUSHMAN POWER PLANT NO. 1, WATER CURVE - SPILLWAY OVERFLOW CHANNEL. July 1928. Reference BT-109 - Cushman No. 1 Hydroelectric Power Plant, Spillway, North Fork of Skokomish River, 5 miles West of Hood Canal, Hoodsport, Mason County, WA

208

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

NASA Astrophysics Data System (ADS)

NCEP/GFS analysis is used to investigate the scale dependence and the interplay between the terms of the atmospheric water budget over West Africa using a dedicated decomposition methodology. The focus is on a 2-month period within the active monsoon period of 2006. Results show that the dominant scales of seasonal mean precipitation and moisture flux divergence over West Africa during the monsoon period are large scales (greater than 1,400 km) except over topography, where mean values of small scales (smaller than 900 km) are strong. Correlations between moisture flux divergences in monsoon and African Easterly Jet layers and precipitation indicate that precipitation is strongly correlated to moisture flux divergence via both large-scale and small-scale processes, but the correlation signal is quite different depending on the region and vertical layer considered. The analysis of the scales associated with the rainfall and the local evaporation over 3 different regions shows that positive correlation exists over the ocean between precipitation and evaporation especially at large scale. Over the continent south of the Sahel, the correlation is negative and driven by large scale. Over the northern part of Sahel, positive correlation is found, only at small scales during the active monsoon period. Lag correlation reveals that the maximum evaporation over the Sahel occurs 1-3 days after the maximum precipitation with maximum contribution from small-scale processes during the first day. This study shows that NCEP/GFS reproduces well the known atmospheric water budget features. It also reveals a new scale dependence of the relative role of each term of the atmospheric water budget. This indicates that such scale decomposition approach is helpful to clarify the functioning of the water cycle embedded in the monsoon system.

Bielli, Soline; Roca, Remy

2010-07-01

209

Position of water in vitrified plants visualised by NMR imaging  

Microsoft Academic Search

Summary Vitrification of plants in vitro is a physiological abnormality of tissue-cultured plants which causes significant losses in the micropropagation industry. Vitrified plants are waterlogged but the position of water within plants has not been identified. Nuclear magnetic resonance (NMR) imaging of normal tissue-cultured, vitrified tissue-cultured, and glasshouse-grown leaves ofGypsophila paniculata showed the distribution of water within the leaves. Normal

K. Gribble; J. Tingle; V. Sarafis; A. Heaton; P. Holford

1998-01-01

210

Photoactivity of carbon-coated anatase for decomposition of iminoctadine triacetate in water  

Microsoft Academic Search

Carbon-coated TiO2 were prepared by a simple heat treatment of the powder mixtures of anatase-type TiO2 (ST-01) with poly(vinyl alcohol) (PVA) at a temperature from 700 to 900°C. Carbon-coated anatase TiO2 showed high photoactivity for the decomposition of iminoctadine triacetae (IT) in its dilute solution under UV irradiation. For all carbon-coated TiO2, the relation between relative concentration of IT in

M. Toyoda; Y. Yoshikawa; T. Tsumura; M. Inagaki

2005-01-01

211

Stable isotope composition of water in desert plants  

Microsoft Academic Search

A survey of the stable isotope content of tissue waters of plants from the Negev desert was conducted. Large differences were\\u000a observed in the extent of enrichment of the heavy isotopes in leaf water relative to local precipitation among different plants.\\u000a This is apparently caused by the species-dependent stratagems adopted by the plants to cope with water stress, primarily by

J. R. Gat; D. Yakir; G. Goodfriend; P. Fritz; P. Trimborn; J. Lipp; I. Gev; E. Adar; Y. Waisel

2007-01-01

212

Cadaver decomposition in terrestrial ecosystems  

NASA Astrophysics Data System (ADS)

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.

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

2007-01-01

213

SIMPLIFIED METHODS FOR ESTIMATING EMISSIONS FROM WASTE WATER TREATMENT PLANTS, BASED ON APPLICATION OF WATER9 TO MODEL PLANTS  

EPA Science Inventory

A set of model waste water treatment plant designs, estimates of their air emissions, and advice for selecting a model plant and scaling it up or down to represent a real plant. This will save much of the analytical work needed to fully model a particular plant using the complet...

214

Variable neighborhood decomposition search for the optimization of power plant cable layout  

Microsoft Academic Search

This paper deals with the optimization of cable layout, which is a problem encountered by Electricité de France (EDF) in power plant design. The problem consists in finding optimized cable routes connecting a set of pairs of facilities, respecting shelves' capacities and a number of other constraints. We show that the problem is equivalent to optimizing the cost of multiple

M.-C. Costa; F.-R. Monclar; M. Zrikem

2002-01-01

215

Decomposition and Plant-Available Nitrogen in Biosolids: Laboratory Studies, Field Studies, and Computer Simulation  

Microsoft Academic Search

1 and the slope of the mares (1992) reported that plant N uptake in a pot study regression between predicted and observed PAN was not significantly was best related to N extracted by pepsin and the C to different from unity. Predicted PAN obtained using mean decomposi- N ratio of the biosolids. Hattori and Mukai (1986) re- tion kinetics was

John T. Gilmour; Craig G. Cogger; Lee W. Jacobs; Gregory K. Evanylo; Dan M. Sullivan

216

The structure of micromycete communities and their synecologic interactions with basidiomycetes during plant debris decomposition  

Microsoft Academic Search

We investigated the interactions between micromycetes and basidiomycete mycelium on plant substrates in the course of their 3-year incubation in the litter of ecologically intact spruce forests of the Central Forest State Biosphere Reservoir (Nelidovo district, Tver oblast). Only 40–60% of the micromycetes were involved in direct antagonistic interactions with basidiomycetous fungi. In terms of the ratio between physiologically active

V. A. Terekhova; T. A. Semenova

2005-01-01

217

Multiunit water resource systems management by decomposition, optimization and emulated evolution  

Microsoft Academic Search

Being one of the essential elements of almost any water resource system, reservoirs are indispensable in our struggle to harness, utilize and manage natural water resources. Consequently, the derivation of appropriate reservoir operating strategies draws significant attention in water resources planning and management. These operational issues become even more important with the ever increasing scale and complexity of water resource

D. Milutin

1998-01-01

218

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

SciTech Connect

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.

Ishijima, T.; Hotta, H.; Sugai, H.; Sato, M. [Plasma Nanotechnology Research Center, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603 (Japan); Honda Electronics Corporation, 20 Oyamazuka, Oiwa-cho, Toyohashi 441-3193 (Japan)

2007-09-17

219

Carbon Assimilation Pathways, Water Relationships and Plant Ecology.  

ERIC Educational Resources Information Center

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)

Etherington, John R.

1988-01-01

220

Carbon Assimilation Pathways, Water Relationships and Plant Ecology.  

ERIC Educational Resources Information Center

|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)|

Etherington, John R.

1988-01-01

221

Effects of land abandonment on plant litter decomposition in a Montado system: relation to litter chemistry and community functional parameters  

Microsoft Academic Search

Changes in land use and subsequent shifts in vegetation can influence decomposition through changes in litter quality (chemistry\\u000a and structure) and alterations of soil temperature and moisture. Our aim was to study the effects of land abandonment on litter\\u000a decomposition in a Mediterranean area of Montado, South Portugal. We tested the hypothesis that decomposition tends to slow\\u000a down with abandonment,

Helena Castro; Claire Fortunel; Helena Freitas

2010-01-01

222

The Effect of Soil Temperature and Moisture on Organic Matter Decomposition and Plant Growth  

Microsoft Academic Search

The effect of soil temperature and moisture on plant growth and mineralisation of organic residues was investigated using N-labelled soybean residues and temperature-controlled tanks in the glasshouse. Treatments were arranged in a factorial design with: three soil temperatures (20, 26 and 30°C), two soil moisture regimes (8% (–800 Kpa) or 12% (–100 Kpa)), soybean residues added (enriched at 1.82 atom

R. C. Hood

2001-01-01

223

Product: 546 - Plants and Plant Parts, Algae, Fresh Water ...  

Center for Biologics Evaluation and Research (CBER)

Text Version... Liberty, MO (Lic. No. 468, STN No. 102223) 9/9/2011 Page 3 of 17 Page 4. 549 - Plants and Plant Parts, Cotton Linters Product: ... More results from www.fda.gov/downloads/biologicsbloodvaccines/allergenics

224

A micropump based on water potential difference in plants  

Microsoft Academic Search

In land plants, water vapor diffuses into the air through the stomata. The loss of water vapor creates a water potential difference\\u000a between the leaf and the soil, which draws the water upward. Quantitatively, the water potential difference is 1–2 MPa which\\u000a can support a water column of 100–200 m. Here we present the design and operation of a biomimetic micropump. The

Jing Min Li; Chong Liu; Kai Ping Zhang; Xue Ke; Zheng Xu; Chun Yu Li; Li Ding Wang

225

Drought perception by plants Do cells of droughted plants experience water stress?  

Microsoft Academic Search

Because of regulations at the whole-plant level, cells of droughted plants do not necessarily experience dehydration. In fact, recent data suggest that they usually do not in the range of water deficits compatible with agriculture. In this range, leaf water potential and cell turgor are frequently maintained at high values in spite of decreasing soil water status. As a consequence,

François Tardieu

1996-01-01

226

The potential of dual-energy computed tomography for quantitative decomposition of soft tissues to water, protein and lipid in brachytherapy  

NASA Astrophysics Data System (ADS)

Dosimetric accuracy of radiation treatment planning in brachytherapy depends on knowledge of tissue composition. It has been speculated that soft tissues can be decomposed to water, lipid and protein. The aim of our work is to evaluate the accuracy of such tissue decomposition. Selected abdominal soft tissues, whose average elemental compositions were taken from literature, were decomposed using dual energy computed tomography to water, lipid and protein via the three-material decomposition method. The quality of the decomposition was assessed using relative differences between (i) mass energy absorption and (ii) mass energy attenuation coefficients of the analyzed and approximated tissues. It was found that the relative differences were less than 2% for photon energies larger than 10 keV. The differences were notably smaller than the ones for water as the transport and dose scoring medium. The choice of the water, protein and lipid triplet resulted in negative elemental mass fractions for some analyzed tissues. As negative elemental mass fractions cannot be used in general purpose particle transport computer codes using the Monte Carlo method, other triplets should be used for the decomposition. These triplets may further improve the accuracy of the approximation as the differences were mainly caused by the lack of high-Z materials in the water, protein and lipid triplet.

Malusek, A.; Karlsson, M.; Magnusson, M.; Alm Carlsson, G.

2013-02-01

227

The potential of dual-energy computed tomography for quantitative decomposition of soft tissues to water, protein and lipid in brachytherapy.  

PubMed

Dosimetric accuracy of radiation treatment planning in brachytherapy depends on knowledge of tissue composition. It has been speculated that soft tissues can be decomposed to water, lipid and protein. The aim of our work is to evaluate the accuracy of such tissue decomposition. Selected abdominal soft tissues, whose average elemental compositions were taken from literature, were decomposed using dual energy computed tomography to water, lipid and protein via the three-material decomposition method. The quality of the decomposition was assessed using relative differences between (i) mass energy absorption and (ii) mass energy attenuation coefficients of the analyzed and approximated tissues. It was found that the relative differences were less than 2% for photon energies larger than 10 keV. The differences were notably smaller than the ones for water as the transport and dose scoring medium. The choice of the water, protein and lipid triplet resulted in negative elemental mass fractions for some analyzed tissues. As negative elemental mass fractions cannot be used in general purpose particle transport computer codes using the Monte Carlo method, other triplets should be used for the decomposition. These triplets may further improve the accuracy of the approximation as the differences were mainly caused by the lack of high-Z materials in the water, protein and lipid triplet. PMID:23322084

Malusek, A; Karlsson, M; Magnusson, M; Carlsson, G Alm

2013-01-16

228

Bamboo-shaped carbon nanotubes generated by methane thermal decomposition using Ni nanoparticles synthesized in water-oil emulsions.  

PubMed

Ni nanoparticles were synthesized using two water-in-oil emulsions formulated with different surfactants and using n-heptane as the organic phase and aqueous nickel acetate as the catalytic metallic precursor. Characterization by transmission electron microscopy showed that the Ni nanoparticles have diameters ranging from 3 to 12 nm, and that the surface is lightly oxidized. The decomposition of diluted methane catalyzed by the as-prepared Ni nanoparticles was studied in a thermogravimetric analyzer (TGA), operated in the 25-930°C range. The weight gains measured during the analysis showed that the Ni nanoparticles decomposed methane above 480°C, producing similar g.C/g.cat ratios (6-7) at the end of the tests. High resolution transmission electron microscopy (HRTEM) confirmed that the carbons collected at 930°C were bamboo-shaped carbon nanotubes (BSCNTs) with well defined conical compartments. The average outside diameter of the tubes was between 30 and 60 nm. PMID:21700468

González, Ismael; De Jesus, Juan; Cañizales, Edgar

2011-06-06

229

Combination of a Pumped Water Power Plant with a Storage Gas Electric Power Plant.  

National Technical Information Service (NTIS)

The possibility of building a storage gas power plant combined with a pumped water power plant was investigated. The combination would offer various cost and construction advantages and the combination compares favorably with conventional thermal electric...

J. Vivod

1974-01-01

230

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...

231

Distribution of volatile organohalogen compounds in petrochemical plant water streams  

Microsoft Academic Search

The study assesses halogenated volatile organic compound concentrations in the water and wastewater streams of a petrochemical plant. Water samples were collected at 11 sampling points during 5 sampling campaigns. The samples were collected from the oil dewaxing unit and in the wastewater treatment plant. Dichloromethane and 1,2-dichloroethane were the most frequently determined compounds. Tetrachloroethene was also detected at the

Marek Tobiszewski; Jacek Namie?nik

2012-01-01

232

A Mathematical Description of Water Flow through Plant Tissues  

Microsoft Academic Search

Non-steady-state flow of water through plant tissues is a complex process to study because of the number of hydraulic parameters involved and the geometric intricacy of the tissues. The importance of understanding water flow through plants together with the increasing power of computers and numerical solution methods have suggested revisiting earlier mathematical approaches to the transport process. In this paper,

Paul J. Schulte; David G. Costa

1996-01-01

233

Measuring Plant Water Status: A Simple Method for Investigative Laboratories.  

ERIC Educational Resources Information Center

|Describes a method suitable for quantitative studies of plant water status conducted by high school or college students and the calculation of the relative water content (RWC) of a plant. Materials, methods, procedures, and results are discussed, with sample data figures provided. (CS)|

Mansfield, Donald H.; Anderson, Jay E.

1980-01-01

234

Air-cooled condensers eliminate plant water use  

SciTech Connect

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.

Wurtz, W.; Peltier, R. [SPX Cooling Technologies Inc. (United States)

2008-09-15

235

Sustainability assessment of desalination plants for water production  

Microsoft Academic Search

The paper presents an attempt to assess sustainability of desalination plants for water production based on resource, environmental and economic indicators. Four types of desalination plants are taken into a consideration: single MSF, dual purpose MSF, RO with local energy consumption and RO with PV electric energy production. The analysis is based on data from desalination plants in Gulf countries.

Naim H. Afgan; Mohammad Darwish; Maria G. Carvalho

1999-01-01

236

Alicante University, closed water cycle, reverse osmosis and water treatment plants  

Microsoft Academic Search

In this paper we will explain the major features which have been considered for the design of a brackish water reverse osmosis plant being constructed in Alicante, in the southeast of Spain. This plant will form part of an integral system cycle that will try to utilize and optimize the water resources of this area. The plant will have the

D. Prats; M. F. Chillón; M. Rubio; J. A. Reverter

1997-01-01

237

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

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.

Zhu, Jianxiao; Yang, Wanqin; He, Xinhua

2013-01-01

238

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

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

Zhu, Jianxiao; Yang, Wanqin; He, Xinhua

2013-04-19

239

Water resource management planning guide for Savannah River Plant  

SciTech Connect

The Water Resource Management Planning Guide provides an outline for the development of a Savannah River Plant Water Resource Management Plan (WRMP) to protect, manage, and monitor the site's water resources. The management plan is based on three principle elements: (1) protection of the water quality, (2) management of the water quantity, and (3) monitoring of the water quality and quantity. The plan will assure that changes in water quality and quantity are identified and that corrective action is implemented as needed. In addition, water management activities within and between Savannah River Plant (SRP) organizations and departments will be coordinated to ensure the proper management of water resources. This document is intended as a guide to suggest goals and objectives that will provide a basis for the development of a water resource plan for SRP. Planning should be flexible rather than rigid, and the plan outlines in this document was prepared to be modified or updated as conditions necessitate. 16 refs., 12 figs.

Hubbard, J.E.; Stephenson, D.E.; Steele, J.L. (Du Pont de Nemours (E.I.) and Co., Aiken, SC (USA). Savannah River Lab.); Gordon, D.E. (Du Pont de Nemours (E.I.) and Co., Aiken, SC (USA). Savannah River Plant)

1988-10-01

240

Foliar water uptake: a common water acquisition strategy for plants of the redwood forest  

Microsoft Academic Search

Evaluations of plant water use in ecosystems around the world reveal a shared capacity by many different species to absorb\\u000a rain, dew, or fog water directly into their leaves or plant crowns. This mode of water uptake provides an important water\\u000a subsidy that relieves foliar water stress. Our study provides the first comparative evaluation of foliar uptake capacity among\\u000a the

Emily Burns Limm; Kevin A. Simonin; Aron G. Bothman; Todd E. Dawson

2009-01-01

241

Survey of All Water Treatment Plant Operators Who Fluoridate Drinking Water in Ohio1  

Microsoft Academic Search

Ohio like several other states in the US is mandated by law to optimally fluoridate all public water systems serving over 5000 people. The purpose of this study was three-fold: 1) to determine if Ohioans on public water supplies are receiving optimally fluoridated water, 2) to determine the knowl- edge level of water treatment plant operators who fluoridate drinking water,

JAMES A. LALUMANOIER; LEONOR C. HERNANDEZ; ANA B. LOCCI

242

Novel Catalytic Behavior of Dense Hot Water in PETN Decomposition Reactions  

Microsoft Academic Search

Under extreme conditions, water is known to exhibit fascinating physical behaviors. Its remarkable structural and phase complexity strongly suggests that its chemical properties may be unusual as well, which have remained largely unrevealed. Using ab inito molecular dynamics simulations, we have recently discovered that water plays an unexpected role in catalyzing complex reactions of a high explosive pentaerythritol tetranitrate (PETN).

Christine Wu; Laurence Fried; Lin Yang; Nir Goldman; Sorin Bastea

2009-01-01

243

Decomposition of chloroform and trichloroethylene in deionized water with the use of low voltage electron beam  

Microsoft Academic Search

Paper presents the experimental setup and the results of the laboratory scale experiment concerning a water purification by electron beam irradiation. The setup was designed to use the circulation water flow in order to control (by the time of circulation) the absorbed dose of radiation. The electron beam was generated in vacuum p=10-5 Torr, and accelerated using the voltage within

Piotr Lubicki; Janes D. Cross; S. Jayaram

1996-01-01

244

An ab initio molecular orbital study of the mechanism for the gas-phase water-mediated decomposition and the formation of hydrates of peroxyacetyl nitrate (PAN).  

PubMed

There is uncertainty in the mechanism for the hydrolysis of peroxyacetyl nitrate (PAN), and experimental attempts to detect products of the direct reaction have been unsuccessful. Ab initio calculations are used to examine the energetics of water-mediated decomposition of gas-phase PAN into acetic acid and peroxynitric acid. On the basis of ab initio calculations, an alternative reaction mechanism for the decomposition of PAN is proposed. The calculations indicate that the barrier for one water addition to PAN is large. However, including additional water molecules reveals a substantially lower energy route. The calculations suggest that the formation of PAN hydrate complexes are energetically favorable and stable. Additional waters are increasingly efficient at stabilizing hydrated PAN. PMID:16117557

Li, Yumin; Francisco, Joseph S

2005-08-31

245

Novel Catalytic Behavior of Dense Hot Water in PETN Decomposition Reactions  

NASA Astrophysics Data System (ADS)

Under extreme conditions, water is known to exhibit fascinating physical behaviors. Its remarkable structural and phase complexity strongly suggests that its chemical properties may be unusual as well, which have remained largely unrevealed. Using ab inito molecular dynamics simulations, we have recently discovered that water plays an unexpected role in catalyzing complex reactions of a high explosive pentaerythritol tetranitrate (PETN). This finding is in contrary to the current view of water as a stable final product of high explosive reactions, and has possible implications in geochemistry, such as reactions in planetary interiors.

Wu, Christine; Fried, Laurence; Yang, Lin; Goldman, Nir; Bastea, Sorin

2009-03-01

246

Physical and Chemical Water Quality of Ilam Water Treatment Plant  

Microsoft Academic Search

4 Abstract: Water usually has some dissolved elements such as solids and gasses. Existences of some elements in water are necessary for human health, but deficiency of many them can cause problems. At this research chemical and physical parameters of produced water in Ilam Water Treatment has determined and compared with Iran and world health organization (WHO) standards. In this

Sajad Mazloomi; Mohammad Hadi Dehghani; Mehdi Norouzi; Mehdi Fazlzadeh Davil

247

Water treatment plant intelligent monitoring in large gas refinery  

Microsoft Academic Search

Water treatment plants have to provide good water quality and at the same time low operational costs. Owing to various physical, chemical and biological interactions water treatment processes are often difficult to handle and reliable predictions for the course of processes are difficult to obtain. Developing monitoring in Automation Control System is a major industrial concern since those systems are

Amir Firoozshahi; Li Mengyang

2010-01-01

248

Energy requirement of water production in dual-purpose plants  

Microsoft Academic Search

In dual-purpose plants (DPPs) producing electricity and water, a realistic estimate for the energy requirement of water production is important since the cost of energy can be combined with equipment, operation and maintenance costs to arrive at the total cost of water production. In a multi-stage flash desalination system, the kind of technology currently being used in most of the

G. P. Maheshwari; M. Al-Ramadhan; M. Al-Abdulhadi

1995-01-01

249

MODELLING OF COAGULANT DOSAGE IN A WATER TREATMENT PLANT  

Microsoft Academic Search

Artificial Neural Network (ANN) techniques are applied to the control of coagulant dosing in a drinking water treatment plant. Coagulant dosing rate is non-linearly correlated to raw water parameters such as turbidity, conductivity, pH, temperature, etc. An important requirement of the application is robustness of the system against erroneous sensor measurements or unusual water characteristics. The hybrid system developed includes

N. Valentin; T. Denoeux; F. Fotoohi

250

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

USGS Publications Warehouse

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.

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

1933-01-01

251

Agar-block microcosms for controlled plant tissue decomposition by aerobic fungi.  

PubMed

The two principal methods for studying fungal biodegradation of lignocellulosic plant tissues were developed for wood preservative testing (soil-block; agar-block). It is well-accepted that soil-block microcosms yield higher decay rates, fewer moisture issues, lower variability among studies, and higher thresholds of preservative toxicity. Soil-block testing is thus the more utilized technique and has been standardized by American Society for Testing and Materials (ASTM) (method D 1413-07). The soil-block design has drawbacks, however, using locally-variable soil sources and in limiting the control of nutrients external (exogenous) to the decaying tissues. These drawbacks have emerged as a problem in applying this method to other, increasingly popular research aims. These modern aims include degrading lignocellulosics for bioenergy research, testing bioremediation of co-metabolized toxics, evaluating oxidative mechanisms, and tracking translocated elements along hyphal networks. Soil-blocks do not lend enough control in these applications. A refined agar-block approach is necessary. Here, we use the brown rot wood-degrading fungus Serpula lacrymans to degrade wood in agar-block microcosms, using deep Petri dishes with low-calcium agar. We test the role of exogenous gypsum on decay in a time-series, to demonstrate the utility and expected variability. Blocks from a single board rip (longitudinal cut) are conditioned, weighed, autoclaved, and introduced aseptically atop plastic mesh. Fungal inoculations are at each block face, with exogenous gypsum added at interfaces. Harvests are aseptic until the final destructive harvest. These microcosms are designed to avoid block contact with agar or Petri dish walls. Condensation is minimized during plate pours and during incubation. Finally, inoculum/gypsum/wood spacing is minimized but without allowing contact. These less technical aspects of agar-block design are also the most common causes of failure and the key source of variability among studies. Video publication is therefore useful in this case, and we demonstrate low-variability, high-quality results. PMID:21339715

Schilling, Jonathan S; Jacobson, K Brook

2011-02-03

252

Electrochemical continuous decomposition of chloroform and other volatile chlorinated hydrocarbons in water using a column type metal impregnated carbon fiber electrode  

Microsoft Academic Search

Trihalomethane and other chlorinated hydrocarbons are known to be toxic to human health. However, removal of these compounds from water is not easy. The authors attempted continuous electrochemical decomposition of chloroform that is the main compound of trihalomethanes and some toxic chlorinated hydrocarbons in water using a metal-impregnated CFE, concentration of chloroform in 0.5 M KâSOâ (the supporting electrolyte) solution

Noriyuki Sonoyama; Tadayoshi Sakata

1999-01-01

253

Photochemical decomposition of pentafluoropropionic acid to fluoride ions with a water-soluble heteropolyacid photocatalyst  

Microsoft Academic Search

Pentafluoropropionic acid (CF3CF2COOH; PFPA) was decomposed to F? and CO2 with a water-soluble homogeneous photocatalyst, H3PW12O40. This is the first example of a photocatalytic system for C?F bond cleavage in a perfluorinated acid compound having both CF3? and ?CF2? units. The catalytic reaction proceeds in water at room temperature under irradiation with UV-Vis light in the presence of oxygen. Gas

Hisao Hori; Yuko Takano; Kazuhide Koike; Shuzo Kutsuna; Hisahiro Einaga; Takashi Ibusuki

2003-01-01

254

A theoretical study on decomposition of formic acid in sub- and supercritical water  

Microsoft Academic Search

The mechanisms of the dissociation of formic acid in subcritical and supercritical water are investigated theoretically. In this dissociation, water molecules around a formic acid play a role of a catalyst by transferring a proton along their locally formed hydrogen bond network. There are two channels of the dissociation, that is, the dehydration (HCOOH-->CO+H2O) starting from the trans-formed formic acid

Takuma Yagasaki; Shinji Saito; Iwao Ohmine

2002-01-01

255

Costly Mistakes In Water Treatment Plant Design For Power Plant Projects  

Microsoft Academic Search

Water treatment cost is a relatively small slice of the operating budget in a typical power plant, generally less than 2 % of the total cost of operation. However, its impact on the plant heat rate, net capacity factor and project profitability can range from significant to disproportionately high. One area of particular concern is the high-purity water requirement in

Luis Carvalho

256

Water Hammer in Nuclear Power Plants.  

National Technical Information Service (NTIS)

The staff reviewed information on water hammer events obtained primarily from Licensee Event Reports and information requests to licensees. Approximately 30 fluid systems in each of four light water reactor designs were also reviewed to determine the pote...

1979-01-01

257

Municipal Waste Water as a Source of Cooling Water for California Electric Power Plants.  

National Technical Information Service (NTIS)

The results of an investigation of sources of municipal waste water for potential use as cooling water in California power plants and the major factors which affect this practice are presented. Municipal treatment facilities in California with discharge v...

T. McDonald

1980-01-01

258

Using biochemically purified water at coke plants  

Microsoft Academic Search

The use of biochemically purified water in place of industrial-grade water for the exhaust-gas scrubbers in the drying department\\u000a of the coal-enrichment shop and for irrigation of the cyclone washers in the coke shops at OAO ZSMK is considered. It is found\\u000a that biochemically purified water may be used for 100% of the water needs in coke production. Using biochemically

L. B. Pavlovich; N. N. Nazarov; V. P. Dolgopolov; A. V. Kalinina; T. A. Bulis; D. V. Bal’tser; V. P. Konstantinov

2008-01-01

259

Aquaporins and water homeostasis in plants  

Microsoft Academic Search

Aquaporins are water channel proteins of vacuolar and plasma membranes. When opened they facilitate the passive movement of water molecules down a water potential gradient. In Arabidopsis, 30 genes have been found that code for aquaporin homologues. Some of these genes code for highly abundant constitutively expressed proteins and some are known to be temporally and spatially regulated during development

Per Kjellbom; Christer Larsson; Ingela Johansson; Maria Karlsson; Urban Johanson

1999-01-01

260

Lowered water table level decreases boreal mire NECB - a question of increased decomposition or decreased photosynthesis?  

NASA Astrophysics Data System (ADS)

The fundamental prerequisite for development and maintenance of mire ecosystems is a positive water balance maintaining a water table level close to the soil surface. One potential effect of climate change at higher latitudes is decreased positive water balance, i.e. increased evapotranspiration and/or decreased precipitation during the growing season leading to a lowered water table level. A lowered water table level is well known to reduce both the net ecosystem exchange (NEE) and most likely also the Net Ecosystem Balance (NECB). Most commonly a reduced NEE is interpreted as resulting from increased respiration. Therefore, a water table draw down is often viewed as a severe threat to the large long-term carbon stores occurring in high latitude peatlands. We used eddy covariance derived data on NEE from a high latitude mire in Northern Sweden during a year with severe drought during the growing season to separate the effects between photosynthesis and ecosystem respiration. The long term annual average NEE at the site is ~59 g C m-2 yr-1 which during the year with summer drought was reduced to 17 g C m-2 yr-1 resulting in a NECB not different from zero. Detailed analyses of the diurnal variation in NEE as well as ordinary NEE-partitioning into gross photosynthesis and respiration respectively revealed a drastic decrease in daytime CO2 uptake while the nighttime CO2 emission hardly was affected at all. Thus, for this widespread type of mire the most significant direct effect of severe droughts is reduced photosynthesis rather then increased respiration.

Nilsson, Mats; Peichl, Matthias; Sagerfors, Jörgen; Ottosson-Lofvenius, Mikaell

2013-04-01

261

Kinetic analysis for ammonia decomposition in supercritical water oxidation of sewage sludge  

SciTech Connect

Supercritical water oxidation was applied to the destruction of municipal excess sewage sludge. The reaction was carried out in a batch reactor with hydrogen peroxide as an oxidant in the temperature range of 723--823 K. Ammonia and acetic acid are found to be refractory intermediates in supercritical water oxidation of organic wastes. Ammonia concentration produced during the reaction was measured as a function of reaction time. The dynamic data were analyzed by a first-order kinetics. The reaction rate constant coincides with those reported in the literature.

Goto, Motonobu; Shiramizu, Daisuke; Kodama, Akio; Hirose, Tsutomu

1999-11-01

262

Decomposition of water with industrial oxygen sensor used as electrolysis cell  

SciTech Connect

Industrial solid state oxygen sensors, using fully stabilized zirconia as electrolyte, were modified and used to split water vapor, mixed with inert gas. Such conditions were chosen for simulating the tritium removal from the ceramic breeder materials in solid blanket fusion reactors. The single cell performances were investigated at 973 K and 200 cm{sup 3}/min flow rate using argon/water vapor mixtures ranging from 100 to 700 vpm. The splitting efficiency was evaluated at 80%; steady state conditions were reached in a few minutes. 14 refs., 4 figs., 1 tab.

Carconi, P.L.; Casadio, S.; Moauro, A.; Petrucci, L. [ENEA C.R. Casaccia, Rome (Italy); Mari, C.M. [Univ. of Milan (Italy)

1995-10-01

263

Sinodal Decomposition and Order Disorder Transformation in a Water Quenched U-6wt%Nb Alloy.  

National Technical Information Service (NTIS)

A combinative approach of microhardness testing, tensile testing, and TEM microstructural analysis has been employed to study phase stability and aging mechanisms of a water-quenched U-6wt%Nb (WQU6Nb) alloy subjected to different aging schedules that incl...

L. Hsiung J. Zhou

2006-01-01

264

Decomposition of polyethylene in radio-frequency nitrogen and water steam plasmas under reduced pressures  

Microsoft Academic Search

The possibility of radio-frequency (RF) nitrogen and water steam plasmas under reduced pressures for gasification of plastic waste as a thermal recycling method has been investigated in order to develop an innovative method for directly recycling plastic waste to hydrogen, synthesis gases or fuels. The products of pyrolysis were analyzed and classified into gaseous fraction and solid soot; and analytical

L. Tang; H. Huang

2007-01-01

265

Reduction of the CO sub 2 decomposition in the transversely excited atmospheric CO sub 2 laser discharge plasma by a very small amount of the water vapor  

SciTech Connect

Using a comprehensive theoretical model, we have theoretically clarified for the first time that the homogeneous catalytic reaction caused by a very small amount of water vapor ({lt}100 ppm) in the closed-cycle, transversely excited atmospheric (TEA) CO{sub 2} laser discharge plasma could considerably reduce the saturation value of the CO{sub 2} molecules decomposition. Effects of the water vapor at this concentration level have been overlooked in the previous investigations. A small concentration variation of the residual water vapor in the experimental laser chambers is thought to be one of the reasons for the considerable disagreements among the published data about the CO{sub 2} equilibrium decomposition level.

Hokazono, H.; Obara, M. (Department of Electrical Engineering, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223 (Japan))

1990-07-02

266

Plant metabolomics: resolution and quantification of elusive peaks in liquid chromatography-mass spectrometry profiles of complex plant extracts using multi-way decomposition methods.  

PubMed

Previous studies on LC-MS metabolomic profiling of 127 F2 Barbarea vulgaris plants derived from a cross of parental glabrous (G) and pubescent (P) type, revealed four triterpenoid saponins (hederagenin cellobioside, oleanolic acid cellobioside, epihederagenin cellobioside, and gypsogenin cellobioside) that correlated with resistance of plants against the insect herbivore, Phyllotreta nemorum. In this study, for the first time, we demonstrate the efficiency of the multi-way decomposition method PARAllel FACtor analysis 2 (PARAFAC2) for exploring complex LC-MS data. PARAFAC2 enabled automated resolution and quantification of several elusive chromatographic peaks (e.g. overlapped, elution time shifted and low s/n ratio), which could not be detected and quantified by conventional chromatographic data analysis. Raw LC-MS data of 127 F2 B. vulgaris plants were arranged in a three-way array (elution time point×mass spectra×samples), divided into 17 different chromatographic intervals and each interval were individually modeled by PARAFAC2. Three main outputs of the PARAFAC2 models described: (1) elution time profile, (2) relative abundance, and (3) pure mass spectra of the resolved peaks modeled from each interval of the chromatographic data. PARAFAC2 scores corresponding to relative abundances of the resolved peaks were extracted and further used for correlation and partial least squares (PLS) analysis. A total of 71 PARAFAC2 components (which correspond to actual peaks, baselines and tails of neighboring peaks) were modeled from 17 different chromatographic retention time intervals of the LC-MS data. In addition to four previously known saponins, correlation- and PLS-analysis resolved five unknown saponin-like compounds that were significantly correlated with insect resistance. The method also enabled a good separation between resistant and susceptible F2 plants. PARAFAC2 spectral loadings corresponding to the pure mass spectra of chromatographic peaks matched well with experimentally recorded mass spectra (correlation based similarity >95%). This enabled to extract pure mass spectra of highly overlapped and low s/n ratio peaks. PMID:23107118

Khakimov, Bekzod; Amigo, José Manuel; Bak, Søren; Engelsen, Søren Balling

2012-10-16

267

PLAYING CATCH-UP WITH CATCHMENT WATER QUALITY THE VAALKOP WATER TREATMENT PLANT UPGRADE CASE STUDY  

Microsoft Academic Search

The first phase of the Vaalkop water treatment plant was commissioned more than 30 years ago soon after the Vaalkop Dam was constructed. The quality of the water abstracted from the Vaalkop Dam was such that a conventional water treatment train utilizing flocculation, settling, sand filtration and disinfection was sufficient to treat the water to potable standards. However, many changes

JJ van der Walt; CJ van der Walt

268

Strategies for Water and Waste Reduction in Dairy Food Plants.  

National Technical Information Service (NTIS)

A study was undertaken to reduce water and waste discharges in a complex, multiproduct dairy food plant through management control and modifications of equipment and processes. The objectives were to develop approaches that would be broadly applicable thr...

I. A. Igbeka M. E. Parkin R. A. M. Delaney W. E. Schiffermiller W. J. Harper

1985-01-01

269

Sacramento River Water Treatment Plant Intake Pier & Access Bridge, ...  

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

Sacramento River Water Treatment Plant Intake Pier & Access Bridge, Spanning Sacramento River approximately 175 feet west of eastern levee on river; roughly .5 mile downstream from confluence of Sacramento & American Rivers, Sacramento, Sacramento County, CA

270

Fluoride Analysis of Water-Treatment-Plant Sludges.  

National Technical Information Service (NTIS)

A method for fluoride analysis of sludges was developed and verified using laboratory-prepared alum sludge. The developed method was then used to measure fluoride concentrations in sludges from selected water treatment plants. Initially, three methods of ...

W. H. Duke

1974-01-01

271

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...

272

Microorganisms and Higher Plants for Waste Water Treatment.  

National Technical Information Service (NTIS)

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 mul...

B. C. Wolverton R. C. McDonald W. R. Duffer

1983-01-01

273

Pollution of Irrigation Reuse Water by Plant Pathogens.  

National Technical Information Service (NTIS)

Systematic sampling of irrigation runoff and reuse systems in Nebraska demonstrated contamination of the water with plant pathogenic fungi and bacteria. In designed reuse systems, nearly 60% of corn fields showing symptoms of Goss's bacterial wilt (Coryne...

J. R. Steadman

1979-01-01

274

An anti-corrosive reactor for the decomposition of halogenated hydrocarbons with supercritical water oxidation  

Microsoft Academic Search

An anti-corrosive reactor was studied, which decomposes halogenated organic compounds by way of supercritical water oxidation (SCWO). Two different types of SCWO reactor were used: a floating type reactor using a non-porous ceramic tube and a transpiring wall-type SCWO reactor using a porous ceramic tube. Reactor configurations were evaluated to protect a SCWO system from corrosion, due to halogenated hydrocarbon

Hyeon-Cheol Lee; Jung-Hyun In; Sang-Young Lee; Jong-Hwa Kim; Chang-Ha Lee

2005-01-01

275

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

NASA Astrophysics Data System (ADS)

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.

Nose, Taisuke; Yokoyama, Yuzo; Minamitani, Yasushi

276

Phytoaccumulation of trace elements by wetland plants. 2: Water hyacinth  

Microsoft Academic Search

Wetland plants are being used successfully for the phytoremediation of trace elements in natural and constructed wetlands. This study demonstrates the potential of water hyacinth (Eichhornia crassipes), an aquatic floating plant, for the phytoremediation of six trace elements. The ability of water hyacinth to take up and translocate six trace elements--As(V), Cd(II), Cr(VI), Cu(II), Ni(II), and Se(VI)--was studied under controlled

Y. L. Zhu; A. M. Zayed; J. H. Qian; M. de Souza; N. Terry

2009-01-01

277

Simulation and analysis of an industrial water desalination plant  

Microsoft Academic Search

In this paper, an industrial medium-scale brackish water reverse osmosis plant based on Dow\\/FilmTec BW30-400 spiral-wound membrane modules was simulated and its performance investigated. Actual operating data is used to validate the computer package. The semi-rigorous model was found to represent the plant with good accuracy; the relative errors in the overall water recovery and salt rejection were 0.37 and

Abderrahim Abbas

2005-01-01

278

Within- and Across-Species Responses of Plant Traits and Litter Decomposition to Elevation across Contrasting Vegetation Types in Subarctic Tundra  

PubMed Central

Elevational gradients are increasingly recognized as a valuable tool for understanding how community and ecosystem properties respond to climatic factors, but little is known about how plant traits and their effects on ecosystem processes respond to elevation. We studied the response of plant leaf and litter traits, and litter decomposability across a gradient of elevation, and thus temperature, in subarctic tundra in northern Sweden for each of two contrasting vegetation types, heath and meadow, dominated by dwarf shrubs and herbaceous plants respectively. This was done at each of three levels; across species, within individual species, and the plant community using a community weighted average approach. Several leaf and litter traits shifted with increasing elevation in a manner consistent with greater conservation of nutrients at all three levels, and the most consistent response was an increase in tissue N to P ratio. However, litter decomposition was less directly responsive to elevation because the leaf and litter traits which were most responsive to elevation were not necessarily those responsible for driving decomposition. At the community level, the response to elevation of foliar and litter traits, and decomposability, varied greatly among the two vegetation types, highlighting the importance of vegetation type in determining ecological responses to climatic factors such as temperature. Finally our results highlight how understanding the responses of leaf and litter characteristics of functionally distinct vegetation types, and the processes that they drive, to temperature helps provide insights about how future climate change could affect tundra ecosystems.

Sundqvist, Maja K.; Giesler, Reiner; Wardle, David A.

2011-01-01

279

Pure oxygen treatment of pesticide plant waste water  

Microsoft Academic Search

Chemagro's waste water treatment plant, which includes pH control, solids removal, equalization, biological treatment (UNOX) and sludge dewatering process units, and which reduces COD by 50.4%, BOD by 92.8%, and phenols by 76.9% is discussed, including the operating problems, operating experience with both the cyrogenic air separation plant and the UNOX system, and advantages.

Pallanich

1978-01-01

280

Water Recovery Using Waste Heat from Coal Fired Power Plants.  

National Technical Information Service (NTIS)

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 plan...

B. P. Dwyer C. W. Morrow S. J. Altman S. W. Webb

2011-01-01

281

Meeting the challenge of power plant water treatment  

Microsoft Academic Search

Biofouling and corrosion control, special situations in cycling units, and water treatment system retrofitting and plant life extension are among the many requirements and problem areas being dealt with by powerplant managers. Specific problems and solutions are offered for the following areas of concern: dechlorination, alternatives to chlorine use, zero discharge requirements, corrosion control, brine concentrators, demineralization, plant life extension,

Rittenhouse

1984-01-01

282

Passive cooling means for water cooled nuclear reactor plants  

Microsoft Academic Search

This patent describes a water cooled, nuclear fission reactor plant having an improved auxiliary passive cooling system for dissipating heat produced during periods of other than normal operation, the nuclear fission reactor plant. It comprises the combination of: a reactor pressure vessel containing a core of heat producing fissionable fuel material provided with reciprocally removable fission control rods and having

D. M. Gluntz; W. J. Oosterkamp; R. M. van Kuijk

1992-01-01

283

Nuclear plant service water system aging degradation assessment: Phase 1  

Microsoft Academic Search

The initial phase of an aging assessment of nuclear power plant service water systems (SWSs) was performed by the Pacific Northwest Laboratory to support the Nuclear Regulatory Commission Nuclear Plant Aging Research (NPAR) program. The SWS was selected for study because of its essential role in the mitigation of and recovery from accident scenarios involving the potential for core-melt. The

D. B. Jarrell; A. B. Jr. Johnson; P. W. Zimmerman; M. L. Gore

1989-01-01

284

Optical fluorescence biosensor for plant water stress detection  

NASA Astrophysics Data System (ADS)

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.

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

2007-06-01

285

Municipal waste water as a source of cooling water for California electric power plants  

Microsoft Academic Search

The results of an investigation of sources of municipal waste water for potential use as cooling water in California power plants and the major factors which affect this practice are presented. Municipal treatment facilities in California with discharge volumes deemed adequate to supply new power plants are identified. Also included is a summary of the experiences of several utilities in

1980-01-01

286

Surface water pollution by herbicides from effluents of waste water treatment plants  

Microsoft Academic Search

Herbicide loads of urban and rural waste water treatment plant effluents were calculated over a one-year period by measuring the herbicide concentrations in 14-day mixed samples. More than three quarters of the total herbicide load of the effluent of the rural waste water treatment plant consists of isoproturon. Particularly large amounts of this substance contribute to the total herbicide load

Walter Schüssler

1998-01-01

287

Iowa's first electrodialysis reversal water treatment plant  

Microsoft Academic Search

In 1979 the City of Washington was notified by the Iowa Department of Natural Resources (IDNR) that the City was in violation of the radium standard for drinking water. The City of Washington authorized an engineering study to determine the most cost-effective and practical way to remove radium and, at the same time, improve overall water quality. Several possible treatment

John Hays

2000-01-01

288

Hydrogen production from water decomposition by redox of Fe2O3 modified with single- or double-metal additives  

NASA Astrophysics Data System (ADS)

Iron oxide modified with single- or double-metal additives (Cr, Ni, Zr, Ag, Mo, Mo-Cr, Mo-Ni, Mo-Zr and Mo-Ag), which can store and supply pure hydrogen by reduction of iron oxide with hydrogen and subsequent oxidation of reduced iron oxide with steam (Fe3O4 (initial Fe2O3)+4H2?3Fe+4H2O), were prepared by impregnation. Effects of various metal additives in the samples on hydrogen production were investigated by the above-repeated redox. All the samples with Mo additive exhibited a better redox performance than those without Mo, and the Mo-Zr additive in iron oxide was the best effective one enhancing hydrogen production from water decomposition. For Fe2O3-Mo-Zr, the average H2 production temperature could be significantly decreased to 276 °C, the average H2 formation rate could be increased to 360.9-461.1 ?mol min-1 Fe-g-1 at operating temperature of 300 °C and the average storage capacity was up to 4.73 wt% in four cycles, an amount close to the IEA target.

Liu, Xiaojie; Wang, Hui

2010-05-01

289

18 CFR 420.51 - Hydroelectric power plant water use charges.  

Code of Federal Regulations, 2010 CFR

...2009-04-01 2009-04-01 false Hydroelectric power plant water use charges. 420...REGULATIONS-WATER SUPPLY CHARGES Hydroelectric Power Water Use Charges § 420.51 Hydroelectric power plant water use charges....

2009-04-01

290

18 CFR 420.51 - Hydroelectric power plant water use charges.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Hydroelectric power plant water use charges. 420...REGULATIONS-WATER SUPPLY CHARGES Hydroelectric Power Water Use Charges § 420.51 Hydroelectric power plant water use charges....

2010-04-01

291

LU Decomposition  

NSDL National Science Digital Library

Created by Stephanie Fitchett and David Smith for the Connected Curriculum Project, the purpose of this module is to examine LU decompositions of matrices and to see how an LU decomposition can improve computational efficiency in solving matrix equations. This is part of a larger collection of learning modules hosted by Duke University.

Smith, David; Fitchett, Stephanie

2010-06-07

292

Effects of water quality on silica fouling of desalination plants  

Microsoft Academic Search

Laboratory tests with simulated waters in the range of those in a prospective desalination plant were carried out to determine the water quality effects on silica precipitation both in batch and dynamic tests using RO membranes. In this study the effect of cations on silica polymerization was investigated. Previous investigations established that the best operating pH range is below 6.5,

R. Sheikholeslami; S. Tan

1999-01-01

293

Monitoring of drinking water treatment plants using ICP?MS  

Microsoft Academic Search

More than sixty inorganic parameters were monitored in the Ter and Llobregat Drinking Water Treatment Plants (DWTPs) using ICP?MS. Both DWTPs supply approximately four million inhabitants with water in Barcelona and neighbouring areas (NE Spain). The profile of inorganic parameters throughout the treatment process is similar in the Ter and Llobregat DWTPs. Sodium, K, Mg, Ca, Si, Cl, SO4 ,

J. F. Llorens; A. Roig; M. Carnicero; F. Valero

2000-01-01

294

Methods for plant water stress evaluation of soybean canopy  

Microsoft Academic Search

It is known that the proline content in the plant leaves increases several times under soil moisture and humidity deficit. This allows us to use it for water stress indicator. Some stress factors as temperature, water deficit etc. lead to increasing of the passive ions current, because the membrane wholeness is decreasing. This can express on the base of the

Vera Tzenova; Yordanka Kirkova; Georgi Stoimenov

2008-01-01

295

Case history advanced coatings for water treatment plant components  

SciTech Connect

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.

Stephenson, L.D.; Kumar, A.

2008-12-15

296

Water release through plant roots: new insights into its consequences at the plant and ecosystem level.  

PubMed

Hydraulic redistribution (HR) is the passive movement of water between different soil parts via plant root systems, driven by water potential gradients in the soil-plant interface. New data suggest that HR is a heterogeneous and patchy process. In this review we examine the main biophysical and environmental factors controlling HR and its main implications at the plant, community and ecosystem levels. Experimental evidence and the use of novel modelling approaches suggest that HR may have important implications at the community scale, affecting net primary productivity as well as water and vegetation dynamics. Globally, HR may influence hydrological and biogeochemical cycles and, ultimately, climate. PMID:22250761

Prieto, Iván; Armas, Cristina; Pugnaire, Francisco I

2012-01-17

297

Leaf Decomposition in a Tropical Rainforest Stream.  

National Technical Information Service (NTIS)

Fungi play an important part in leaf litter decomposition in terrestrial ecosystems in both temperate and tropical regions. There are few published reports dealing with decomposition in running waters, and no work has been done in tropical streams. Result...

D. E. Padgett

1975-01-01

298

USE of mine pool water for power plant cooling.  

SciTech Connect

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.

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

2006-11-27

299

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

NASA Astrophysics Data System (ADS)

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.

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

2011-12-01

300

Plants for water recycling, oxygen regeneration and food production.  

PubMed

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. PMID:11537696

Bubenheim, D L

1991-10-01

301

Photochemical decomposition of oxalic, glyoxalic and pyruvic acid catalysed by iron in atmospheric waters  

NASA Astrophysics Data System (ADS)

Kinetics of the iron(III) catalysed photochemical degradation of oxalic, glyoxalic and pyruvic acids has been investigated under conditions representative of atmospheric waters. Degradation rates for the organic acids are proportional to the concentration of iron (III)-substrate complexes and sunlight intensity. Under September noon sunlight irradiation (0.65m Einstein m -2s -1), 1 ?M dissolved iron(III) has a potential to catalyse the degradation of oxalic acid at a rate of 10 ± 1 nM s -1; of glyoxalic acid, 7 ± 1 nM s -1; and of pyruvic acid, 8 ± 1 nM s -1. The half life for the photolysis of oxalic acid and ?-keto acids catalysed by iron(III) is in the order of a few minutes whenever the concentration of dissolved iron(III) is comparable to that of the organic acids. A detailed reaction mechanism has been proposed in which the complex formation between iron(III) and the substrate is a key step. The evidence, that such an iron(III) catalysed photochemical process serves as a major removal pathway for atmospheric oxalic and ?-keto acids, has also been discussed.

Zuo, Yuegang; Hoigné, Jürg

302

Water vulnerabilities for existing coal-fired power plants.  

SciTech Connect

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

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

2010-08-19

303

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...

304

Foliar water uptake: a common water acquisition strategy for plants of the redwood forest.  

PubMed

Evaluations of plant water use in ecosystems around the world reveal a shared capacity by many different species to absorb rain, dew, or fog water directly into their leaves or plant crowns. This mode of water uptake provides an important water subsidy that relieves foliar water stress. Our study provides the first comparative evaluation of foliar uptake capacity among the dominant plant taxa from the coast redwood ecosystem of California where crown-wetting events by summertime fog frequently occur during an otherwise drought-prone season. Previous research demonstrated that the dominant overstory tree species, Sequoia sempervirens, takes up fog water by both its roots (via drip from the crown to the soil) and directly through its leaf surfaces. The present study adds to these early findings and shows that 80% of the dominant species from the redwood forest exhibit this foliar uptake water acquisition strategy. The plants studied include canopy trees, understory ferns, and shrubs. Our results also show that foliar uptake provides direct hydration to leaves, increasing leaf water content by 2-11%. In addition, 60% of redwood forest species investigated demonstrate nocturnal stomatal conductance to water vapor. Such findings indicate that even species unable to absorb water directly into their foliage may still receive indirect benefits from nocturnal leaf wetting through suppressed transpiration. For these species, leaf-wetting events enhance the efficacy of nighttime re-equilibration with available soil water and therefore also increase pre-dawn leaf water potentials. PMID:19585154

Limm, Emily Burns; Simonin, Kevin A; Bothman, Aron G; Dawson, Todd E

2009-07-08

305

Management of power-plant water and wastewater in water-short regions. [Conference paper  

Microsoft Academic Search

The water management program for the Arizona Nuclear Power Project (ANPP) project starts by utilizing a source considered by most users as a waste product. This recovered waste stream meets more than 95% of the plant water needs. Through a relatively extensive treatment system, the quality of this wastewater is upgraded so the water can be concentrated to 15 times

A. C. Rogers; J. W. Kluesener; C. V. Jensen

1980-01-01

306

Energy from fresh and brackish water aquatic plants  

SciTech Connect

Aquatic plants can achieve relatively high biomass productivities when compared to terrestrial plants because they need not be water-stressed and can be optimally supplied with nutrients. Based on literature reports, productivities in southern US regions of about 40 to 60 t/ha-yr (dry weight basis) can be predicted for green algae or marsh plants and about 80 t/ha-yr for water hyacinth. Higher productivities may be possible in exceptionally favorable locations by assuming development of advanced cultivation technologies and genetic selection of improved strains. The lack of established cultivation systems and low-cost harvesting processes imposes great uncertainties on the cost of biomass production by aquatic plants. Three potentially practical aquatic biomass energy systems are chemicals production from microalgae, alcohol production from marsh plants, and methane production from water hyacinths. At present, aquatic plants are not being used commercially as a fuel source any place in the world. Nevertheless, it is clear that aquatic plants have potentially high biomass productivities and, specifically for the case of microalgae, could produce a high-quality, high-value biomass suitable for conversion to fuels and extraction of other products. A list of the relative advantages and disadvantages of aquatic plant energy systems in comparison with the concepts of terrestrial tree or herbaceous plant energy farming is given. Three favorable aspects of aquatic plant biomass systems should be stressed - the relative short-term research and development effort that will be required to determine the practical feasibility of such systems, the continuous production nature of such systems, and the relative independence of aquatic biomass systems from soil characteristics and weather fluctuations. The fast generation times of most aquatic plants allow rapid data acquisition, as compared to even short-rotation trees.

Benemann, J.R.

1981-01-01

307

Decomposition of Carboxylic Acids in Water by O3, O3\\/H2O2, and O3\\/Catalyst  

Microsoft Academic Search

This paper studies the decomposition of formic, oxalic and maleic acids by O3, O3\\/catalyst, and O3\\/H2O2. The catalytic effect of Co, Ni, Cu, Mn, Zn, Cr, and Fe ions is investigated. The results showed that—Co and Mn have the highest catalytic activity for the decomposition of oxalic acid while the catalytic effect of the studied ions is insignificant on the

Ahmed A. Abd El-Raady; Tsuyoshi Nakajima

2005-01-01

308

Soluble arsenic removal at water treatment plants  

SciTech Connect

Arsenic profiles were obtained from full-scale conventional treatment (coagulation, Fe-Mn oxidation, or softening) plants, facilitating testing of theories regarding arsenic removal. Soluble As(V) removal efficiency was controlled primarily by pH during coagulation, be Fe{sup +2} oxidation and Fe(OH){sub 3} precipitation during Fe-Mn oxidation, and by Mg(OH){sub 2} formation during softening. Insignificant soluble As(V) removal occurred during calcite precipitation at softening plants or during Mn{sup +2} oxidation-precipitation at Fe-Mn oxidation plants. The extent of soluble As(V) removal during coagulation and softening treatments was lower than expected. Somewhat surprisingly, during coagulation As(V) removal efficiencies were limited by particulate aluminum formation and removal, because much of the added coagulant was not removed by 0.45-{mu}m-pore-size filters. At one utility, reducing the coagulation pH from 7.4 to 6.8 (at constant alum dose) improved removal of particulate aluminum, thereby enhancing soluble As(V) removal during treatment.

McNeill, L.S.; Edwards, M. [Univ. of Colorado, Boulder, CO (United States). Dept. of Civil Engineering

1995-04-01

309

Tips for Teaching Plant Water Relations.  

ERIC Educational Resources Information Center

|Presents two techniques involving simple and inexpensive demonstrations: (1) explains how pressure inside cells gives them mechanical strength, and (2) shows how water can be pulled up stems. Both can be adapted to suit a variety of levels of instruction. (PR)|

Berg, Virginia

1993-01-01

310

Thermal power plant water treatment process  

Microsoft Academic Search

The requirements and treatment costs of water used in a fossil fuel fired power station are reduced by a process which employs multiple reverse osmosis stages. This process also employs station waste heat to concentrate solid waste material to facilitate disposal thereof.

H. Ludwig; K. Marquardt

1982-01-01

311

Review: plant life in extremely acidic waters  

Microsoft Academic Search

In acidic waters, a variety of autotrophic organisms are found including phototrophic bacteria, phytoplankton, filamentous- and micro-benthic algae and macrophytes. To explain the occurrence and distribution of primary producers we must answer the following question. What is acidity and where and how does it influence autotrophic metabolism in aquatic ecosystems? The very low pH per se will have profound effects

B Nixdorf; A Fyson; H Krumbeck

2001-01-01

312

Wetlands: Water, Wildlife, Plants, and People.  

ERIC Educational Resources Information Center

|Describes wetlands and explains their importance to man and ecology. Delineates the role of water in wetlands. Describes how wetlands are classified: estuarine, riverine, lacustrine, palustrine, and marine. Accompanying article is a large, color poster on wetlands. Describes an activity where metaphors are used to explore the functions of…

Vandas, Steve

1992-01-01

313

Performance of a hotel chilled water plant with cool storage  

SciTech Connect

A comprehensive monitoring suite was installed at a large convention hotel located in San Francisco, CA. The instrumentation was used for a research project to evaluate the effectiveness of electricity price based controls that automate response to real time pricing and to characterize the operation and performance of the hotel's chilled water plant that included a newly installed ice cool storage system. The hotel operates under real-time electricity rates. To date, over four years of data have been collected. Data included electricity use for all chillers, secondary coolant, chilled water, condenser pumps, and the cooling tower fans. Thermal flow data were also collected for the storage system, ice chiller, direct cooling chillers, and chilled water load loops. This paper (1) describes the chilled water plant, (2) defines the performance measurement objectives for the project, (3) discusses operational experience with the plant, focusing on the cool storage system, (4) analyzes chilled water plant and cool storage system operation by examining the charge/discharge heat flow data, and (5) evaluates how well the plant as a whole and the cool storage system specifically met cooling loads of the facility, and how this affected their use.

Gillespie, K.L.; Blanc, S.L.; Parker, S.

1999-07-01

314

Strategies of Plant Water Use under Stochastic Hydrologic Conditions  

NASA Astrophysics Data System (ADS)

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

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

2003-12-01

315

Plant growth promoting bacteria enhance water stress resistance in green gram plants  

Microsoft Academic Search

Plant growth promoting bacterial (PGPB) strains Pseudomonas fluorescens Pf1 and endophytic Bacillus subtilis EPB5, EPB22, EPB 31 were tested for their capacity to induce water stress related proteins and enzymes in green gram (Vigna radiata) plants. Among the different bacteria used, P. fluorescens Pf1 increased the vigour index, fresh weight and dry weight of green gram seedlings in vitro. Quantitative

D. Saravanakumar; M. Kavino; T. Raguchander; P. Subbian; R. Samiyappan

2011-01-01

316

Predawn plant water potential does not necessarily equilibrate with soil water potential under well-watered conditions  

Microsoft Academic Search

Predawn leaf water potential (Ow) and xylem pressure potential (Op) are expected to be in equilibrium with the soil water potential (soil Ow) around roots of well-watered plants. We surveyed 21 plant species (desert, chaparral, and coastal salt marsh species, as well as two temperate tree and two crop species) for departures from this expectation and for two potential mechanisms

L. A. Donovan; M. J. Linton; J. H. Richards

2001-01-01

317

Institutional impediments to using alternative water sources in thermoelectric power plants  

Microsoft Academic Search

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

Elcock

2011-01-01

318

WATER TREATMENT PLANT OPTIMIZATION BY CONTROLLING THE SUSPENDED SOLIDS PHYSICOCHEMICAL ENVIRONMENT  

Microsoft Academic Search

Optimizing water treatment plant operation is a concept should be applied to all plants because some operational improvements can always be made. Optimization at a water treatment plant can be considered achieved when certain goals are being met to attain the most efficient use of the water treatment plant facilities. The most important goals are to reduce the water wastes,

Kamal El-Nahhas

319

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

SciTech Connect

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.

Ehleringer, J.R.

1992-11-17

320

Water use, productivity and interactions among desert plants  

SciTech Connect

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.

Ehleringer, J.R.

1992-11-17

321

The role of planted forests in urban water budgets (Invited)  

NASA Astrophysics Data System (ADS)

In arid regions which are not naturally forested, urban trees are sustained through the redistribution of water resources as irrigation. Assessments of outdoor water use in Southwestern US cities have shown that not only is 30-75% of residential water use expended on outdoor landscapes, but that irrigation is frequently in excess of estimated plant demand. Thus, there is a need to understand the factors which influence the magnitude and variability of water use of urban trees. A complicating factor in assessing urban tree water use is the widely recognized heterogeneity of urban environments. Human choices and decision-making result in a landscape with significant variability in water and nutrient inputs, microclimate, biotic inputs and vegetation composition. In order to quantify urban tree water use and explain variation in water use resulting from variability in resource availability and species composition, we have conducted a combination of sapflux, growth and isotopic studies on more than 35 common (primarily non-native) tree species in the Los Angeles basin. The objective of these studies was to determine how much variability in water use and water use efficiency exists within and between commonly planted urban tree species, and what factors explain or can be used to predict this variability. Through these studies we have found considerable differences (up to two fold) in tree transpiration within a given species, attributable to differences in water and nutrient availability and tree planting density. Additionally, we have found substantial variation in the water use of different species: at typical urban planting densities, peak transpiration rates can be more than ten times greater for high transpiring trees than low transpiring trees. Finally, we found whole tree water use efficiency to vary across species by a factor of up to a hundred, explained to a large degree by the climate conditions (especially vapor pressure deficit) in the native ranges of these non-native trees. On the scale of the entire city of Los Angeles, we estimate that the urban forest could use as much as 50% of the total municipal water use. Overall, we have found that urban trees can use substantial quantities of water, and that species choice matters greatly in determining urban landscape water use.

McCarthy, H. R.; Pataki, D. E.; Litvak, E.

2009-12-01

322

Vascular aquatic plants for mineral nutrient removal from polluted waters  

Microsoft Academic Search

Aquatic plants have potential as feedstuffs in certain nations, but the economics of harvesting and processing would prohibit\\u000a their direct utilization as a forage in technologically advanced nations. However, nutrient pollution is accelerating rates\\u000a of eutrophication of natural waters in many areas. Aquatic plants produce large standing crops and accumulate large amounts\\u000a of nutrients. Systems based on the harvest of

Claude E. Boyd

1970-01-01

323

Response of floodplain grassland plant communities to altered water regimes  

Microsoft Academic Search

Floodplain grasslands are often composed of a mosaic of plant communities controlled by hydrological regime. This article\\u000a examines the sensitivity of floodplain grassland plant communities to water regime using reciprocal transplantation of an\\u000a inundation grassland and a flood-meadow within an English floodplain. Experimental treatments comprised control, transplanted\\u000a and lifted plots; the last treatment, in order to elucidate any disturbance effects

Sarah E. Toogood; Chris B. Joyce; Stephen Waite

2008-01-01

324

Water, plants, and early human habitats in eastern Africa  

PubMed Central

Water and its influence on plants likely exerted strong adaptive pressures in human evolution. Understanding relationships among water, plants, and early humans is limited both by incomplete terrestrial records of environmental change and by indirect proxy data for water availability. Here we present a continuous record of stable hydrogen-isotope compositions (expressed as ?D values) for lipid biomarkers preserved in lake sediments from an early Pleistocene archaeological site in eastern Africa—Olduvai Gorge. We convert sedimentary leaf- and algal-lipid ?D values into estimates for ancient source-water ?D values by accounting for biochemical, physiological, and environmental influences on isotopic fractionation via published water–lipid enrichment factors for living plants, algae, and recent sediments. Reconstructed precipitation and lake-water ?D values, respectively, are consistent with modern isotopic hydrology and reveal that dramatic fluctuations in water availability accompanied ecosystem changes. Drier conditions, indicated by less negative ?D values, occur in association with stable carbon-isotopic evidence for open, C4-dominated grassland ecosystems. Wetter conditions, indicated by lower ?D values, are associated with expanded woody cover across the ancient landscape. Estimates for ancient precipitation amounts, based on reconstructed precipitation ?D values, range between approximately 250 and 700 mm·y?1 and are consistent with modern precipitation data for eastern Africa. We conclude that freshwater availability exerted a substantial influence on eastern African ecosystems and, by extension, was central to early human proliferation during periods of rapid climate change.

Magill, Clayton R.; Ashley, Gail M.; Freeman, Katherine H.

2013-01-01

325

Treating waste water from heat and electrical power plants and state regional power plants  

Microsoft Academic Search

Water is often contaminated with oil and other petroleum products when used by local and regional power plants. This article outlines the various methods of treating oil contaminated water and removing emulsions. Coagulation and flocculation are commonly used methods of treatment, but there are other means including flotation and electrochemical methods. Ammonium nitrite was used to accelerates the oil removal

1995-01-01

326

Pilot plant comparison study of two commercial nanofiltration membranes in a drinking water treatment plant  

Microsoft Academic Search

A wide range of commercial membranes were tested and compared at laboratory scale in order to select the most appropriate for improving the final water quality of a real drinking water treatment plant (DWTP). Most of the membranes tested showed a reduction of trihalomethanes formation potential (THMFP) higher than 90%. In this work, several NF membranes were tested at laboratory

Gemma Ribera; Laia Llenas; Miquel Rovira; Joan de Pablo; Xavier Martinez-Llado

2012-01-01

327

Assessing the water quality index of water treatment plant and bore wells, in Delhi, India.  

PubMed

Water quality monitoring exercise was carried out with water quality index (WQI) method by using water characteristics data for bore wells and a water treatment plant in Delhi city from December 2006 to August 2007. The water treatment plant received surface water as raw water, and product water is supplied after treatment. The WQI is used to classify water quality as excellent, good, medium, bad, and very bad. The National Sanitation Foundation WQI procedure was used to calculate the WQI. The index ranges from 0 to 100, where 100 represents an excellent water quality condition. Water samples were collected monthly from a bore well in Nehru Camp (site 1), a bore well in Sanjay Gandhi pumping station (site 2), and water treatment plant in Haiderpur (site 3). Five parameters were analyzed, namely, nitrate, pH, total dissolved solids, turbidity, and temperature. We found that the WQI was around 73-80 in site 3, which corresponds to "good," and it decreased to 54.32-60.19 and 59.93-70.63 in site 1 and site 2, respectively, indicating that these bore wells were classified as "medium" quality. PMID:19343515

Chaturvedi, M K; Bassin, J K

2009-04-03

328

Spinodal Decomposition and Order-Disorder Transformation in a Water-Quenched U-6wt%Nb Alloy  

SciTech Connect

A combinative approach of microhardness testing, tensile testing, and TEM microstructural analysis has been employed to study phase stability and aging mechanisms of a water-quenched U-6wt%Nb (WQU6Nb) alloy subjected to different aging schedules that include artificial aging of WQ-U6Nb at 200 C, natural aging of WQ-U6Nb at ambient temperatures for 15 to18 years, and accelerative aging of the naturally aged (NA) alloy at 200 C. During the early stages of artificial aging at 200 C, the microhardness values continuously increase as a result of the development of a fine-scale compositional modulation (wavelength: 3 nm) caused by spinodal decomposition. Coarsening of the modulated structure occurs after prolonged aging of WQ-U6Nb at 200 C for 16 hours, which leads to a decrease of microhardness. Phase instability has also been found to occur in the NA alloy, in which the formation of partially ordered phase domains resulting from an atomic-scale spinodal modulation (wavelength: 0.5 nm) renders the appearance of antiphase domain boundaries (APBs) in TEM images. Although 18-year natural aging does not cause a significant change in hardness, it affects dramatically the aging mechanism of WQ-U6Nb subjected to the accelerative aging at 200 C. The result of microhardness measurement shows that the hardness values continuously increase until after aging for 239 hours, and the total hardness increment is twice in magnitude than that in the case of the artificial aging of water-quenched alloy at 200 C. The anomalous increment of hardness for the accelerative aging of NA alloy can be attributed to the precipitation of an ordered U{sub 3}Nb phase. It is accordingly concluded that the long-term natural aging at ambient temperatures can detour the transformation pathway of WQ U-6Nb alloy; it leads to the order-disorder transformation and precipitation of ordered phase in the alloy.

Hsiung, L; Zhou, J

2006-09-12

329

Mixing effects of understory plant litter on decomposition and nutrient release of tree litter in two plantations in northeast china.  

PubMed

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

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

2013-10-15

330

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

PubMed Central

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.

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

2013-01-01

331

Some effects of changing soil chemistry on decomposition of plant litters and cellulose on a Scottish moor  

Microsoft Academic Search

Summary  Nitrogen (N), phosphorus (P), calcium (Ca) and soluble carbohydrates (CHO) were each added at three levels to a moorland podzol,\\u000a and the decomposition of three constrasting untreated substrates (Calluna vulgaris stems,Molinia caerulea leaves, and cotton strips) compared between treated and untreated plots. All soil treatments increased decay rates of all\\u000a three substrates, except for the highest levels of P and

D. D. French

1988-01-01

332

Do rock fragments participate to plant water and mineral nutrition?  

NASA Astrophysics Data System (ADS)

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.

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

2010-05-01

333

Comparing actual evapotranspiration and plant water potential on a vineyard  

NASA Astrophysics Data System (ADS)

Agricultural water requirement in arid and semi-arid environments represents an important fraction of the total water consumption, suggesting the need of appropriate water management practices to sparingly use the resource. Furthermore the quality and quantity of some crops products, such as grape, is improved under a controlled amount of water stress. The latter is related, on a side to actual evapotranspiration (ET) through water demand, on the other side to plant water content through leaf water potential. Residual energy balance approaches based on remote sensing allow to estimate the spatial distribution of daily actual ET at plant scale, representing an useful tool to detect its spatial variability across different cultivars and even within each parcel. Moreover, the connection between actual ET and leaf water potential is still not well assessed, especially under water stress conditions, even if farmers use leaf water potential to plan irrigation. However residual energy balance methods are based on the hypothesis that storage terms are negligible, at least during the remote sensor overpass. Indeed, energy balance approaches estimate daily actual ET from the instantaneous value at the overpass time using a daily integration method. The paper first verifies this latter assumption using field data acquired by a flux tower on a whole phenological period. Then, the actual ET values measured by eddy covariance tower were analyzed together with water potential measured using a Scholander chamber; the analysis highlights that, under water stress conditions, daily actual ET is inversely linearly related with water potential. These results suggest the possibility to use remote sensing-based ET as support for irrigation management at plot scale.

Maltese, Antonino; Cammalleri, Carmelo; Capodici, Fulvio; Ciraolo, Giuseppe; Colletti, Francesco; La Loggia, Goffredo; Santangelo, Tanino

2011-10-01

334

Water uptake in green roof microcosms: Effects of plant species and water availability  

Microsoft Academic Search

Green roofs are engineered ecosystems that rely on vegetation to provide services such as reduction of roof temperatures. Drought resistance is critical for plant survival on shallow-substrate green roofs, but potential trade-offs exist between water-use efficiency and ecosystem functions like transpirative cooling. Water loss from simulated green roof systems (microcosms) each containing 1 of 14 plant species belonging to 4

Derek Wolf; Jeremy T. Lundholm

2008-01-01

335

Long-term performance of an industrial water desalination plant  

Microsoft Academic Search

The long-term performance of a medium-scale industrial spiral wound reverse osmosis (RO) water desalination plant was studied. Operational data were analysed for a period of 1500 days as a basis for evaluating the performance variation with time. A theoretical model based on the solution-diffusion mass-transfer theory and concentration polarization was employed to extract the water and salt permeability coefficients. The

Nader Al-Bastaki; Abderrahim Abbas

2004-01-01

336

Water transport in plants: Role of the apoplast  

Microsoft Academic Search

The present state of modelling of water transport across plant tissue is reviewed. A mathematical model is presented which incorporates the cell-to-cell (protoplastic) and the parallel apoplastic path. It is shown that hydraulic and osmotic properties of the apoplast may contribute substantially to the overall hydraulic conductivity of tissues (Lpr) and reflection coefficients (67-1). The model shows how water and

Ernst Steudle; Jiargen Frensch

1996-01-01

337

Effects of water stress on male gametophyte development in plants  

Microsoft Academic Search

Male reproductive development in plants is highly sensitive to water deficit during meiosis in the microspore mother cells.\\u000a Water deficit during this stage inhibits further development of microspores or pollen grains, causing male sterility. Female\\u000a fertility, in contrast, is quite immune to stress. The injury is apparently not caused by desiccation of the reproductive\\u000a tissue, but is an indirect consequence

Hargurdeep S. Saini

1997-01-01

338

Water transport in plant cuticles: an update.  

PubMed

The scale, mechanism, and physiological importance of cuticular transpiration were last reviewed in this journal 5 and 10 years ago. Progress in our basic understanding of the underlying processes and their physiological and structural determinants has remained frustratingly slow ever since. There have been major advances in the quantification of cuticular water permeability of stomata-bearing leaf and fruit surfaces and its dependence on leaf temperature in astomatous surfaces, as well as in our understanding of the respective roles of epicuticular and intracuticular waxes and molecular-scale aqueous pores in its physical control. However, understanding the properties that determine the thousand-fold differences between permeabilities of different cuticles remains a huge challenge. Molecular biology offers unique opportunities to elucidate the relationships between cuticular permeability and structure and chemical composition of cuticles, provided care is taken to quantify the effects of genetic manipulation on cuticular permeability by reliable experimental approaches. PMID:16822810

Kerstiens, Gerhard

2006-07-05

339

Integrated operation of drinking water treatment plant at Amsterdam water supply  

Microsoft Academic Search

Water treatment plants are in general robust and designs are based on the performance of individual processes with pre-set boundary conditions. It is assumed that an integral approach of the entire treatment plant can lead to more efficient operation. Taking into account the developments in sensoring, automation and computation, it is a challenge to improve quality and reliability of the

G. J. Bosklopper; L. C. Rietveld; R. Babuska; B. Smaal; J. Timmer

340

Stomatal Behavior and Water Relations of Waterlogged Tomato Plants  

PubMed Central

The effects of waterlogging the soil on leaf water potential, leaf epidermal conductance, transpiration, root conductance to water flow, and petiole epinasty have been examined in the tomato (Lycopersicon esculentum Mill.). Stomatal conductance and transpiration are reduced by 30% to 40% after approximately 24 hours of soil flooding. This is not due to a transient water deficit, as leaf water potential is unchanged, even though root conductance is decreased by the stress. The stomatal response apparently prevents any reduction in leaf water potential. Experiments with varied time of flooding, root excision, and stem girdling provide indirect evidence for an influence of roots in maintaining stomatal opening potential. This root-effect cannot be entirely accounted for by alterations in source-sink relationships. Although 1-aminocyclopropane-1-carboxylic acid, the immediate precursor of ethylene, is transported from the roots to the shoots of waterlogged tomato plants, it has no direct effect on stomatal conductance. Ethylene-induced petiole epinasty develops coincident with partial stomatal closure in waterlogged plants. Leaf epinasty may have beneficial effects on plant water balance by reducing light interception.

Bradford, Kent J.; Hsiao, Theodore C.

1982-01-01

341

A faster plant stem-water extraction method.  

PubMed

Oxygen and hydrogen isotope ratios of stem water have been used by several studies which relate the ecophysiology of plants to their water source. Undoubtedly, there are several other applications and research areas which could use this type of analysis. However, the most often used methods of extracting stem water are slow, limiting the rate of sampling and consequently preventing a deeper understanding of spatial and temporal plant water source use. We have developed a faster batch method of stem-water extraction and compare it with the most commonly used online method of stem-water extraction. Samples are sealed in 18 cm long ampoules having their extremities placed sample end in a heating block and the condensing end in a cooling block, and allowed to distill overnight. Up to 72 samples can be distilled overnight and sealed the next morning. The isotope ratios of water distilled by the batch method introduced here compared with those from the online method were in excellent agreement. In addition to being faster, this method does not need the monitoring of hot water baths and liquid nitrogen traps during distillation and does not require a complex vacuum system. PMID:17154343

Vendramini, Patricia F; Sternberg, Leonel da S L

2007-01-01

342

Desert Emergency - Lack of Water - How to Find and Collect Water. Plants and Human Survival in the Desert.  

National Technical Information Service (NTIS)

This study concentrated on the plant and environmental factors which influence the yield of water transpiration which can be collected from 2 widespread plant species, Retama raetam and Phragmites australis; the latter plant gives a much higher yield. Thi...

Y. Gutterman

1985-01-01

343

Tragedy of the commons in plant water use  

NASA Astrophysics Data System (ADS)

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.

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

2006-06-01

344

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

Microsoft Academic Search

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

T. A. Kimmell; J. A. Veil

2009-01-01

345

An Interpretation of Some Whole Plant Water Transport Phenomena  

PubMed Central

A treatment of water flow into and through plants to the evaporating surface of the leaves is presented. The model is driven by evaporation from the cell wall matrix of the leaves. The adsorptive and pressure components of the cell wall matric potential are analyzed and the continuity between the pressure component and the liquid tension in the xylem established. Continuity of these potential components allows linking of a root transport function, driven by the tension in the xylem, to the leaf water potential. The root component of the overall model allows for the solvent-solute interactions characteristic of a membrane-bound system and discussion of the interactions of environmental variables such as root temperature and soil water potentials. A partition function is developed from data in the literature which describes how water absorbed by the plant might be divided between transpiration and leaf growth over a range of leaf water potentials. Relationships between the overall system conductance and the conductance coefficients of the various plant parts (roots, xylem, leaf matrix) are established and the influence of each of these discussed. The whole plant flow model coupled to the partition function is used to simulate several possible relationships between leaf water potential and transpiration rate. The effects of changing some of the partition function coefficients, as well as the root medium water potential on these simulations is illustrated. In addition to the general usefulness of the model and its ability to describe a wide range of situations, we conclude that the relationships used, dealing with bulk fluid flow, diffusion, and solute transport, are adequate to describe the system and that analogically based theoretical systems, such as the Ohm's law analogy, probably ought to be abandoned for this purpose.

Fiscus, Edwin L.; Klute, Arnold; Kaufmann, Merrill R.

1983-01-01

346

Measurement of plant water status by the pressure chamber technique  

Microsoft Academic Search

The pressure chamber has been widely used in the measurement of total water potential and pressure-volume relations of leaves, twigs and, to a lesser extent, roots. Some of the benefits and precautions in its use in these studies are reviewed and discussed. The pressure chamber has also been used to determine hydraulic resistances of plants, to collect xylem sap, to

Neil C. Turner

1988-01-01

347

STRATEGIES FOR WATER AND WASTE REDUCTION IN DAIRY FOOD PLANTS  

EPA Science Inventory

A study was undertaken to reduce water and waste discharges in a complex, multiproduct dairy food plant through management control and modifications of equipment and processes. The objectives were to develop approaches that would be broadly applicable throughout the dairy industr...

348

Fetal loss and work in a waste water treatment plant  

Microsoft Academic Search

We investigated pregnancy outcomes in 101 wives of workers employed in a waste water treatment plant (WWTP), and verified fetal losses by hospital records. Paternal work histories were compiled and each of the 210 pregnancies was assigned a paternal exposure category. The relative risk of fetal loss was increased when paternal exposure to the WWTP occurred around the time of

R. W. Morgan; L. Kheifets; D. L. Obrinsky; M. D. Whorton; D. E. Foliart

1984-01-01

349

A PNEUMATIC WEIGHING DEVICE FOR PLANT WATER USE DETERMINATIONS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Direct gravimetric determinations of whole plant water use in pot studies can be time consuming due to the tremendous labor required to physically lift containers for placement on weighing scales. Our objective was to design and construct a container weighing system that could be rapidly deployed a...

350

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...

351

WATER BASED MAGNETIC FLUID IMPACT ON YOUNG PLANTS GROWING  

Microsoft Academic Search

The effect of a water-based magnetic fluid was tested on two plant species (pumpkin and maize) in their very early ontogenetic stages. The magnetic fluid biocompatibility was assured by the ferrophase structure (magnetite) as well as by its coating molecules (citric acid) - these molecules being well tolerated by living bodies. The magnetic fluid volume fractions used in experiment were

ZENOVIA OLTEANU; Lucian Blaga; I. Cuz

352

Phosphorus nutrition and water stress tolerance in wheat plants  

Microsoft Academic Search

The effect of phosphorus (P) nutrition and soil water availability (W) on the growth of wheat (Triticum aestivum L.) plants was studied in two pot experiments. Several levels of P supply were applied once before sowing. Before seedling establishment, the pots were kept near 100% of field capacity (FC). Afterwards, half of the pots were maintained between 60–70% FC. Control

D. Rodriguez; J. Goudriaan; M. Oyarzabal; M. C. Pomar

1996-01-01

353

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...

354

Water permeability of plant cuticles: permeance, diffusion and partition coefficients  

Microsoft Academic Search

Using isolated cuticular membranes from ten woody and herbaceous plant species, permeance and diffusion coefficients for water were measured, and partition coefficients were calculated. The cuticular membranes of fruit had much higher permeance and diffusion coefficients than leaf cuticular membranes from either trees or herbs. Both diffusion and partition coefficients increased with increasing membrane thickness. Thin cuticles, therefore, tend to

Matthias Becker; Gerhard Kerstiens; Jörg Schönherr

1986-01-01

355

Water quality investigation of Kingston Fossil Plant dry ash stacking  

Microsoft Academic Search

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

Bohac

1990-01-01

356

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

357

Wastewater minimisation using central reusable water storage in batch plants  

Microsoft Academic Search

This paper presents a continuous-time mathematical formulation for freshwater and wastewater minimisation in multipurpose batch plants with and without a central reusable water storage facility. The minimisation of wastewater is achieved through the exploitation of recycle and reuse opportunities. A superstructure that entails all the possible recycle and reuse possibilities is used as the basis for the formulation. Initia lly,

Thokozani Majozi

2005-01-01

358

Diurnal Water Table Fluctuations: An Underutilized Indicator of Ground-water Consumption by Plants  

Microsoft Academic Search

Hydrographs from shallow wells in areas with phreatophytes frequently display a distinctive pattern of diurnal fluctuations. Although first linked to variations in plant water use early in the last century, these diurnal fluctuations have received relatively little attention in the ecohydrology literature. In particular, little attention has been given to exploiting the information embedded in the water-level data to improve

J. P. Bauer; J. Shea; J. Keller; J. J. Butler; G. Kluitenberg; D. O. Whittemore

2005-01-01

359

Biogeochemistry of Decomposition and Detrital Processing  

NASA Astrophysics Data System (ADS)

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

Sanderman, J.; Amundson, R.

2003-12-01

360

Assessment of drinking water quality of Borg el-Arab water purification plant.  

PubMed

Borg El-Arab drinking water purification plant takes its raw water from El-Noubaria Canal at the kilometer 95. EI-Noubaria canal gets its water from the Nile at two points. The main bulk of water comes from El-Riah El-Behiery, while the second source of water coming from El-Riah El-Nassery. There are four agricultural drains at the kilometer 53.0, 66.0, 71.9 and 85.4 which return back to the canal and represent the sources of pollution of the canal. Chemical, physical and trace elements analysis were carried out for raw and treated water of Borg El-Arab drinking water purification plant. It was found that the quality of treated water for the different parameter, are in agreement with the Ministry of Health Decree No 108/1995 for drinking water. Regarding total dissolved solids level, the quality of water was fair during Autumn and Summer as its value was 876.7 mg/l and 701.2 mg/l respectively, it was poor during spring as it reached 1113 mg/l, while during winter it was unacceptable (1312.7 mg/l) which exceed the higher permissible limit of the Ministry of Health Decree No 108/1995. This high TDS values make objectionable tastes in the public water supplied to Borg El-Arab city and the North West coast summer resorts. This taste of water provides no assurance to the public that such water is free of pathogens or toxic inorganic chemicals. So, we recommend El-Hager canal as new intake source for providing Borg El-Arab drinking water purification plant with raw water free from pollutants and low in total dissolved solids concentration. PMID:17216986

Mohamed, M G

2001-01-01

361

Plant Morphological and Biochemical Responses to Field Water Deficits  

PubMed Central

Activity of glutathione reductase has been related to stress tolerance; however, these enzyme assays are generally conducted at 25°C. Foliage temperature varies greatly in the field in response to soil water availability and ambient conditions and this may affect enzyme response. This study was conducted to determine the effect of changing foliage temperature on glutathione reductase activity of wheat under field conditions. Wheat leaf glutathione reductase was purified and the temperature response of the enzyme was determined at 2.5°C intervals between 12.5 and 45°C. These data, in conjunction with continuous measurements of field-grown wheat foliage temperatures, were used to compare the temperature-related changes in potential glutathione reductase activities in water stressed and control plants. Assuming saturating substrate levels, the results indicate that early in the season the daily potential enzyme activity of the irrigated and stressed plants could never have reached the daily activity predicted from the 25°C (room temperature) measurements. Later in the season, the daily potential activity of the irrigated plants was lower, and the daily potential activity of the stressed plants was higher, than the activities predicted from the 25°C determinations. These results suggest that a better understanding of the regulation of plant metabolism will be obtained by linking continuous temperature measurements of plant foliage with enzyme responses to temperature.

Burke, John J.; Hatfield, Jerry L.

1987-01-01

362

Ethylene plant steam strips waste water to recover benzene  

SciTech Connect

Du Pont's Sabine River Works' ethylene plant in Orange, Tex., has selected a steam stripping process to remove benzene from its waste water stream. Timely completion of the project plan diverted a possible cleanup cost in excess of $100 million. The Du Pont plant was constructed in 1967 to crack feedstocks ranging from 50% ethane/50% propane to purity ethane. The plant is currently cracking purity ethane in the presence of dilution steam to produce ethylene and various byproducts. The dilution steam is added to improve selectivity and reduce fouling in the heater coils. The cracked gas exists the heaters and goes to the quench tower, where the steam and a portion of the heavier hydrocarbons such as benzene, toulene, and styrene are condensed. After the cracked gas is cooled in the quench tower, it is compressed and then separated into the various products in the distillation train. The condensed steam and hydrocarbons are separated in the quench settler. The hydrocarbons are sent to the heavy aromatic distillate (HAD) storage for sale. The condensed steam, with dissolved hydrocarbons, combines with the effluent from the API separator and goes to the dissolved gas flotation (DGF) unit, which was installed in 1988. When the plant was started up, the quench water was recycled, to make dilution steam. However, this system was plagued by plugging problems, and the quench water was rerouted to the biponds. The API separator is the collection point for all of the oil and water blowdowns in the ethylene plant. In addition to the blowdowns, large quantities of rainwater go to the API separator. The hydrocarbons leaving the DGF go to HAD storage, and the water goes to the bioponds.

Taylor, M.A. (E.I. du Pont de Nemours and Co. Inc., Orange, TX (US))

1991-05-27

363

Occurrence of Giardia cysts and Cryptosporidium oocysts in raw and treated water from two water treatment plants in Selangor, Malaysia  

Microsoft Academic Search

The occurrence of Giardia cysts and Cryptosporidium oocysts was determined both in the raw water and the treated waters from two water treatment plants in Selangor, Malaysia between July 1994 and January 1995. At each treatment plant, raw and treated water samples were collected fortnightly on 10 separate occasions. Physical parameters, including dissolved oxygen, pH, temperature, conductivity, turbidity and free

R. A. Ahmad; E. Lee; I. T. L. Tan; A. G. Mohamad-Kamel

1997-01-01

364

INNOVATIVE FRESH WATER PRODUCTION PROCESS FOR FOSSIL FUEL PLANTS  

SciTech Connect

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.

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

2003-09-01

365

Long-Distance Water Transport in Aquatic Plants.  

PubMed

Acropetal mass flow of water is demonstrated in two submerged angiosperms, Lobelia dortmanna L. and Sparganium emersum Rehman by means of guttation measurements. Transpiration is absent in truly submerged plants, but the presence of guttation verifies that long-distance water transport takes place. Use of tritiated water showed that the water current arises from the roots, and the main flow of water is channeled to the youngest leaves. This was confirmed by measurement of guttation, which showed the highest rates in young leaves. Guttation rates were 10-fold larger in the youngest leaf of S. emersum (2.1 [mu]L leaf-1 h-1) compared with the youngest leaf of L. dortmanna (0.2 [mu]L leaf-1 h-1). This is probably due to profound species differences in the hydraulic conductance (2.7 x 10-17 m4 Pa-1 s-1 for S. emersum and 1.4 x 10-19 m4 Pa-1 s-1 for L. dortmanna). Estimates derived from the modified Hagen-Poiseuille equation showed that the maximum flow velocity in xylem vessels was 23 to 84 cm h-1, and the required root pressure to drive the flow was small compared to that commonly found in terrestrial plants. In S. emersum long-distance transport of water was shown to be dependent on energy conversion in the roots. The leaves ceased to guttate when the roots were cooled to 4[deg]C from the acclimatization level at 15[deg]C, whereas the guttation was stimulated when the temperature was increased to 25[deg]C. Also, the guttation rate decreased significantly when vanadate was added to the root medium. The observed water transport is probably a general phenomenon in submerged plants, where it can act as a translocation system for nutrients taken up from the rich root medium and thereby assure maximum growth. PMID:12232030

Pedersen, O.

1993-12-01

366

Multifarious Power Plant Water Intake Structure (MWIS). A Design Concept to Reduce the Environmental Effects of Cooling Water Intake Structures.  

National Technical Information Service (NTIS)

The design for the Multifarious Power Plant Water Intake Structure (MWIS) was developed to reduce the entrainment and impingement of aquatic organisms in water intakes requiring large volumes of cooling water. Its uniqueness is based upon the operation of...

B. Chezar

1976-01-01

367

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

PubMed

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

Assouline, Shmuel; Or, Dani

2013-07-02

368

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

NASA Astrophysics Data System (ADS)

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.

Cortis, C.; Montaldo, N.

2009-12-01

369

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

NASA Astrophysics Data System (ADS)

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.

Cortis, C.; Montaldo, N.

2009-04-01

370

Identification of the primary circuit dynamics in a pressurized water nuclear power plant  

Microsoft Academic Search

This paper presents the results of the parameter estimation procedure for the primary circuit dynamics of a VVER-type nuclear power plant. The model structure is a low dimensional lumped nonlinear model published previously in Fazekas et al. (2007a). The parameter estimation method uses the modular decomposition of the system model for obtaining physically meaningful initial parameter estimates. The final parameter

M. Hangos

371

INNOVATIVE FRESH WATER PRODUCTION PROCESS FOR FOSSIL FUEL PLANTS  

SciTech Connect

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.

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

2004-09-01

372

Planted floating bed performance in treatment of eutrophic river water.  

PubMed

The objective of the study was to treat eutrophic river water using floating beds and to identify ideal plant species for design of floating beds. Four parallel pilot-scale units were established and vegetated with Canna indica (U1), Accords calamus (U2), Cyperus alternifolius (U3), and Vetiveria zizanioides (U4), respectively, to treat eutrophic river water. The floating bed was made of polyethylene foam, and plants were vegetated on it. Results suggest that the floating bed is a viable alternative for treating eutrophic river water, especially for inhibiting algae growth. When the influent chemical oxygen demand (COD) varied from 6.53 to 18.45 mg/L, total nitrogen (TN) from 6.82 to 12.25 mg/L, total phosphorus (TP) from 0.65 to 1.64 mg/L, and Chla from 6.22 to 66.46 g/m(3), the removal of COD, TN, TP, and Chla was 15.3 %-38.4 %, 25.4 %-48.4 %, 16.1 %-42.1 %, and 29.9 %-88.1 %, respectively. Ranked by removal performance, U1 was best, followed by U2, U3, and U4. In the floating bed, more than 60 % TN and TP were removed by sedimentation; plant uptake was quantitatively of low importance with an average removal of 20.2 % of TN and 29.4 % of TP removed. The loss of TN (TP) was of the least importance. Compared with the other three, U1 exhibited better dissolved oxygen (DO) gradient distributions, higher DO levels, higher hydraulic efficiency, and a higher percentage of nutrient removal attributable to plant uptake; in addition, plant development and the volume of nutrient storage in the C. indica tissues outperformed the other three species. C. indica thus could be selected when designing floating beds for the Three Gorges Reservoir region of P. R. China. PMID:23737127

Bu, Faping; Xu, Xiaoyi

2013-06-05

373

Recycling of filter backwash water and alum sludge for reuse in water treatment plants. Technical report  

SciTech Connect

The feasibility of recycling backwash water and alum sludge generated from water-purification plants has been investigated. The waste recycle system presented here consists of (a) recycling the filter backwash water to the intake system for reproduction of potable water, (b) dividing the combined sludge into two fractions for alum solubilization, respectively, in an acid reactor and an alkaline reactor, (c) centrifugal filtering the inert silts from alum solutions by two separate water-solid separators for ultimate disposal, and (d) returning the solubilized alums from the two separate water-solid separators in proper proportions for reuse as flocculant(s). The proposed recycle process was designed to provide a cost-effective system for achieving zero water discharge and alum recovery from a water-purification plant. Recommended process-design parameters necessary to achieve the above stated goals were established. Experimental results tend to suggest that practical designs based on the proposed water recycle, sludge thickening, and alum recovery (STAR) system are both technically and economically feasible.

Krofta, M.; Wang, L.K.

1988-06-15

374

Growing potato plants by the water culture technique  

Microsoft Academic Search

A water culture technique was developed for the study of the nutrient requirements of the potato plant. Tuber formation was\\u000a avoided by pinching off the stolons as they developed and hence vegetative growth could be studied without the complication\\u000a of abnormal tuber formation in the culture solution. The K deficiency symptoms obtained by this method were essentially the\\u000a same as

Kwok H. Fong; Albert Ulrich

1969-01-01

375

Combined water and power plant (CWPP) — a novel desalination technology  

Microsoft Academic Search

In recent years, an enormous increase of fuel cost and greater demand for fresh water have imposed tremendous challenges for researchers to pursue a drive towards more energy-efficient desalination technology. In the search for a more energy-efficient desalination process, the next generation plants will use a combination of membrane processes with multi-stage flash (MSF)\\/multi-effect distillation (MED) thermal processes to harness

Fazle Mahbub; M. N. A. Hawlader; A. S. Mujumdar

2009-01-01

376

Water reuse in a paper reprocessing plant. Final report  

Microsoft Academic Search

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\\/sec (125 gpm). Normal operation is now zero discharge with approximately 0.76 1\\/sec (12 gpm) fresh

L. E. Streebin; G. W. Reid; P. Law; C. Hogan

1976-01-01

377

Nitrogen Removal from Eutrophicated Water by Aquatic Plants  

Microsoft Academic Search

\\u000a Increased N concentration in an aquatic ecosystem is one of important causes of eutrophication. Aquatic higher plants in eutrophic\\u000a water bodies can remove N by direct uptake and by being a carbon source and a surface substrate for microorganisms and algae,\\u000a which also use N as a nutrient and can transform N into gaseous forms that escape from the ecosystem.

Olga Babourina; Zed Rengel

378

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

National Technical Information Service (NTIS)

The validity and practical implications are discussed of the proposition that CO2 enrichment of the leaf environment enhances plant growth and, simultaneously, decreases plant water use. A theoretical analysis of the water and carbon dioxide balance of pl...

C. H. M. Van Bravel

1972-01-01

379

Magnetic Resonance Imaging of Plants: Water Balance and Water Transport in Relation to Photosynthetic Activity  

Microsoft Academic Search

Nuclear magnetic resonance (NMR) and nuclear magnetic resonance imaging (MRI) techniques are described in relation to applications\\u000a on intact plants. These techniques are non-destructive and non-invasive and can be used to study the dynamics of plant water\\u000a relations and water transport, e.g., as a function of environmental (stress) conditions. Non-spatially resolved NMR as well\\u000a as two-dimensional or even three-dimensional imaging

Henk Van As; Carel W. Windt

2008-01-01

380

Association of water spectral indices with plant and soil water relations in contrasting wheat genotypes  

PubMed Central

Spectral reflectance indices can be used to estimate the water status of plants in a rapid, non-destructive manner. Water spectral indices were measured on wheat under a range of water-deficit conditions in field-based yield trials to establish their relationship with water relations parameters as well as available volumetric soil water (AVSW) to indicate soil water extraction patterns. Three types of wheat germplasm were studied which showed a range of drought adaptation; near-isomorphic sister lines from an elite/elite cross, advanced breeding lines, and lines derived from interspecific hybridization with wild relatives (synthetic derivative lines). Five water spectral indices (one water index and four normalized water indices) based on near infrared wavelengths were determined under field conditions between the booting and grain-filling stages of crop development. Among all water spectral indices, one in particular, which was denominated as NWI-3, showed the most consistent associations with water relations parameters and demonstrated the strongest associations in all three germplasm sets. NWI-3 showed a strong linear relationship (r2 >0.6–0.8) with leaf water potential (?leaf) across a broad range of values (–2.0 to –4.0 MPa) that were determined by natural variation in the environment associated with intra- and inter-seasonal affects. Association observed between NWI-3 and canopy temperature (CT) was consistent with the idea that genotypes with a better hydration status have a larger water flux (increased stomatal conductance) during the day. NWI-3 was also related to soil water potential (?soil) and AVSW, indicating that drought-adapted lines could extract more water from deeper soil profiles to maintain favourable water relations. NWI-3 was sufficiently sensitive to detect genotypic differences (indicated by phenotypic and genetic correlations) in water status at the canopy and soil levels indicating its potential application in precision phenotyping.

Gutierrez, Mario; Reynolds, Matthew P.; Klatt, Arthur R.

2010-01-01

381

Association of water spectral indices with plant and soil water relations in contrasting wheat genotypes.  

PubMed

Spectral reflectance indices can be used to estimate the water status of plants in a rapid, non-destructive manner. Water spectral indices were measured on wheat under a range of water-deficit conditions in field-based yield trials to establish their relationship with water relations parameters as well as available volumetric soil water (AVSW) to indicate soil water extraction patterns. Three types of wheat germplasm were studied which showed a range of drought adaptation; near-isomorphic sister lines from an elite/elite cross, advanced breeding lines, and lines derived from interspecific hybridization with wild relatives (synthetic derivative lines). Five water spectral indices (one water index and four normalized water indices) based on near infrared wavelengths were determined under field conditions between the booting and grain-filling stages of crop development. Among all water spectral indices, one in particular, which was denominated as NWI-3, showed the most consistent associations with water relations parameters and demonstrated the strongest associations in all three germplasm sets. NWI-3 showed a strong linear relationship (r(2) >0.6-0.8) with leaf water potential (psi(leaf)) across a broad range of values (-2.0 to -4.0 MPa) that were determined by natural variation in the environment associated with intra- and inter-seasonal affects. Association observed between NWI-3 and canopy temperature (CT) was consistent with the idea that genotypes with a better hydration status have a larger water flux (increased stomatal conductance) during the day. NWI-3 was also related to soil water potential (psi(soil)) and AVSW, indicating that drought-adapted lines could extract more water from deeper soil profiles to maintain favourable water relations. NWI-3 was sufficiently sensitive to detect genotypic differences (indicated by phenotypic and genetic correlations) in water status at the canopy and soil levels indicating its potential application in precision phenotyping. PMID:20639342

Gutierrez, Mario; Reynolds, Matthew P; Klatt, Arthur R

2010-07-01

382

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

SciTech Connect

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.

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

2008-01-01

383

Innovative Fresh Water Production Process for Fossil Fuel Plants  

SciTech Connect

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.

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

2005-09-01

384

IRRIGATION WATER SALINITY EFFECTS ON SOME SOIL WATER CONSTANTS AND PLANT  

Microsoft Academic Search

Germination and pot experiment was conducted under green house conditions to study the influence of irrigation water salinity on yield and chemical composition of wheat (Triticum vulgare L. cv Sakha 8) plant grown in sandy and calcareous soil. Irrigation water salinity levels were, 0.43 (control), 4.85, 6.60 and 8.86 dS m-1, S1, S2, S3 and S4, respectively. Results concluded that,

A. A. M. M. Ragab; F. A. Hellal; M. Abd

2008-01-01

385

Water and plant cells: Notes on a teaching scheme for 0-level  

Microsoft Academic Search

Suggestions are offered for teaching some aspects of water economy in plant cells. These include diffusion and osmosis, transport of water within plants, the part played by turgor in structural support and its implications for plant organs or whole plants. Wherever possible the degree of sophistication thought desirable at this level is indicated. Some appropriate practical demonstrations are referred to.

H. W. Grenville

1983-01-01

386

Common mycorrhizal networks provide a potential pathway for the transfer of hydraulically lifted water between plants  

Microsoft Academic Search

Plant roots may be linked by shared or common mycorrhizal networks (CMNs) that constitute pathways for the transfer of resources among plants. The potential for water transfer by such networks was examined by manipulating CMNs independently of plant roots in order to isolate the role(s) of ectomycor- rhizal (EM) and arbuscular mycorrhizal fungal (AMF) networks in the plant water balance

Louise M. Egerton-Warburton; JoseIgnacio Querejeta; Michael F. Allen

2007-01-01

387

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

Microsoft Academic Search

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

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

2006-01-01

388

Performance evaluation of ten years operation experience of brackish water RO desalination in Manfouha plants, Riyadh  

Microsoft Academic Search

There are two sources that provide Riyadh City with potable water: 1. Desalinated seawater from Al Jubail plants pumped from Saudi Arabia's East Coast. (represents about 60%). 2. Brackish water from deep and shallow wells, which are primarily treated by eight plants of which six are, followed by reverse osmosis desalination plants. (represents about 40%).Among the six RO plants supplying

Raed I. S. Al Mudaiheem; Sami O. A. Al Yousef; Tamer Sharif; A. K. M. Amirul Islam

1998-01-01

389

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...

390

Mercury Bioaccumulation Potential from Wastewater Treatment Plants in Receiving Waters  

NASA Astrophysics Data System (ADS)

In early 2007, the Water Environment Research Foundation (WERF) mercury bioavailability project was initiated in response to the establishment of mercury Total Maximum Daily Load (TMDL) criteria around the country. While many TMDLs recognize that point sources typically constitute a small fraction of the mercury load to a water body, the question was raised concerning the relative bioavailablity of mercury coming from various sources. For instance, is the mercury discharged from a wastewater treatment plant more or less bioavailable than mercury contributed from other sources? This talk will focus on the results of a study investigating approaches to the estimation of bioavailability and potential bioaccumulation of mercury from wastewater treatment plants and other sources in receiving waters. From the outset, a working definition of bioavailability was developed which included not only methylmercury, the form that readily bioaccumulates in aquatic food chains, but also bioavailable inorganic mercury species that could be converted to methylmercury within a scientifically reasonable time frame. Factors that enhance or mitigate the transformation of inorganic mercury to methylmercury and its subsequent bioaccumulation were identified. Profiles were developed for various sources of mercury in watersheds, including wastewater treatment plants, with regard to methylmercury and inorganic bioavailable mercury, and the key factors that enhance or mitigate mercury bioavailability. Technologies that remove mercury from wastewater were reviewed and evaluated for their effect on bioavailability. A screening procedure was developed for making preliminary estimates of bioavailable mercury concentrations and fluxes in wastewater effluents and in fresh, estuarine and marine receiving waters. The procedure was validated using several diverse river and reservoir data sets. A "Bioavailability Tool" was developed which allows a user to estimate the bioavailability of an effluent and compare it to another, and to mix an effluent in a receiving water to estimate bioavailability in the near- and far-field. As part of this project, a study was undertaken to evaluate methylmercury and reactive mercury in wastewater effluents. Effluent samples from 7 municipal wastewater plants from around the Unites States were collected weekly over a ten week period from late June through August of 2008. These data represent the first comprehensive study of bioavailable mercury in wastewater effluents and have not been published elsewhere. Initial data suggest that bioavailable (methyl plus reactive) mercury is less than 30 percent of total unfiltered mercury. Reactive mercury percentages (relative to dissolved total mercury) are somewhat higher than were initially predicted from theoretical calculations. This presentation will overview the project as a whole with a focus on the bioavailability study of these 7 wastewater plants.

Dean, J. D.; Mason, R. P.

2008-12-01

391

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

SciTech Connect

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.

Grimvall, A.; Jonsson, S.; Karlsson, S.; Savenhed, R.; Boren, H. (Dept. of Water and Environmental Studies, Linkoping Univ., S-58183 Linkoping (SE))

1991-05-01

392

Control of small reverse osmosis desalination plants with feed water bypass  

Microsoft Academic Search

Small reverse osmosis desalination plants without pH control normally use a feed water bypass to modify the permeate conductivity by mixing a little amount of feed water with the permeate. Plants with this characteristic have a different system configuration and the conductivity is usually not controlled. In this contribution, small plants with feed water bypass are studied from the dynamic

A. Gambier; E. Badreddin

2009-01-01

393

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...

394

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...

395

Impact of plant density and microbial composition on water quality from a free water surface constructed wetland  

Microsoft Academic Search

Aims: To correlate microbial community composition and water quality chan- ges within wetland cells containing varying plant densities and composition in a free water surface (FWS) constructed wetland. Methods and Results: Water chemistry was monitored weekly for nitrate, orthophosphate, and suspended solids, at various sites throughout the wetland for 6 months. Treatment ponds with 50% plant cover had about a

A. M. Ibekwe; S. R. Lyon; M. Leddy; M. Jacobson-Meyers

2006-01-01

396

Cadaver decomposition in terrestrial ecosystems  

Microsoft Academic Search

A dead mammal (i.e. cadaver) is a high quality resource (narrow carbon:nitrogen ratio, high water content) that releases an\\u000a intense, localised pulse of carbon and nutrients into the soil upon decomposition. Despite the fact that as much as 5,000 kg\\u000a of cadaver can be introduced to a square kilometre of terrestrial ecosystem each year, cadaver decomposition remains a neglected\\u000a microsere. Here

David O. Carter; David Yellowlees; Mark Tibbett

2007-01-01

397

Water permeability of plant cuticles: The effect of temperature on diffusion of water  

Microsoft Academic Search

The effect of temperature on water permeability of plant cuticles (astomatous Citrus leaf cuticles) has been investigated. The Arrhenius plot (logarithm of the permeability coefficient vs. 1\\/temperature) has two linear portions that intersect at 44° C. Evidence is presented to show that this intersection represents the solid\\/liquid phase transition of cuticular lipids. As the Arrhenius plot has only one phase

J. Schönherr; K. Eckl; H. Gruler

1979-01-01

398

Soil water content and water supply of plants in the southern Crimea  

NASA Astrophysics Data System (ADS)

In cinnamonic soils of the Nikitsky Botanical Garden (Crimea), the average productive water reserves (WR) under different plants in 1981-1990 exhibited close correlation with the field water capacity (FC) and the productive moisture range, which is equal to the difference between the FC and the permanent wilting point (WP). The soil water content (SWC) regularly increased with the depth. An 8-year-long variation cycle of the meteorological conditions and the WR was revealed. A correlation between the WR and the precipitation was noted. The relationship of the occurrence frequencies of the FC and WR with their values was analogous to the Maxwell distribution close to the normal (Gaussian) distribution.

Sudnitsyn, I. I.

2008-01-01

399

Diurnal Water Table Fluctuations: An Underutilized Indicator of Ground-water Consumption by Plants  

NASA Astrophysics Data System (ADS)

Hydrographs from shallow wells in areas with phreatophytes frequently display a distinctive pattern of diurnal fluctuations. Although first linked to variations in plant water use early in the last century, these diurnal fluctuations have received relatively little attention in the ecohydrology literature. In particular, little attention has been given to exploiting the information embedded in the water-level data to improve understanding of plant water use. Results from two field sites in western Kansas will be presented to demonstrate the insights that can be gleaned from these fluctuations. At one site the vegetation is representative of the native riparian-zone assemblage found over much of the Great Plains (major phreatophyte is the cottonwood [ Populus spp.]), whereas at the other site the vegetation is dominated by invasive species (salt cedar [ Tamarix spp.] and Russian olive [ Elaeagnus angustifoli]). Both sites have a network of shallow wells and neutron probe access tubes for monitoring water-table position and moisture content, respectively. The onset and termination of ground-water use by plants during the growing season is readily identifiable at both sites. Data from the first site show that the maximum depth from which phreatophytes can draw water depends on the previous hydrologic conditions experienced at the site, and not the physiological limits of the plant. Phreatophyte control actions (mulch cutting and chemical treatment) have recently been applied in a sequential fashion to a portion of the second site. The initial impact of those actions on ground-water consumption was not as large as expected, suggesting that forbs and grasses, which were not significantly impacted by these actions, also use substantial amounts of ground water. The magnitude of the diurnal fluctuations ranges appreciably between the sites, and even between wells at the same site. A portion of this difference can be attributed to variations in plant water uptake across a site. Often, however, a more important factor is variation in the specific yield of the sediments in the vicinity of the water table. Thus, the hydrogeology of the shallow subsurface cannot be ignored in interpretations of the fluctuations.

Bauer, J. P.; Shea, J.; Keller, J.; Butler, J. J.; Kluitenberg, G.; Whittemore, D. O.

2005-12-01

400

The decomposition of windrowed, chipped logging slash and tree seedling response: A plant growth and nuclear magnetic resonance spectroscopy study  

Microsoft Academic Search

Forest management practices historically have reduced the mass of logging slash to facilitate planting and reduce fire risk. However, coarse woody debris (CWD) is considered an important component of unmanaged forests of western and coastal North America. An experiment was established in northern California using chipped logging slash concentrated in windrows to emulate large fallen logs to determine the effects

Caroline M. Preston; Ronald J. Smernik; Robert F. Powers; John G. McColl; Therese M. McBeath

2011-01-01

401

A global experiment suggests climate warming will not accelerate litter decomposition in streams but might reduce carbon sequestration.  

PubMed

The decomposition of plant litter is one of the most important ecosystem processes in the biosphere and is particularly sensitive to climate warming. Aquatic ecosystems are well suited to studying warming effects on decomposition because the otherwise confounding influence of moisture is constant. By using a latitudinal temperature gradient in an unprecedented global experiment in streams, we found that climate warming will likely hasten microbial litter decomposition and produce an equivalent decline in detritivore-mediated decomposition rates. As a result, overall decomposition rates should remain unchanged. Nevertheless, the process would be profoundly altered, because the shift in importance from detritivores to microbes in warm climates would likely increase CO(2) production and decrease the generation and sequestration of recalcitrant organic particles. In view of recent estimates showing that inland waters are a significant component of the global carbon cycle, this implies consequences for global biogeochemistry and a possible positive climate feedback. PMID:21299824

Boyero, Luz; Pearson, Richard G; Gessner, Mark O; Barmuta, Leon A; Ferreira, Verónica; Graça, Manuel A S; Dudgeon, David; Boulton, Andrew J; Callisto, Marcos; Chauvet, Eric; Helson, Julie E; Bruder, Andreas; Albariño, Ricardo J; Yule, Catherine M; Arunachalam, Muthukumarasamy; Davies, Judy N; Figueroa, Ricardo; Flecker, Alexander S; Ramírez, Alonso; Death, Russell G; Iwata, Tomoya; Mathooko, Jude M; Mathuriau, Catherine; Gonçalves, José F; Moretti, Marcelo S; Jinggut, Tajang; Lamothe, Sylvain; M'Erimba, Charles; Ratnarajah, Lavenia; Schindler, Markus H; Castela, José; Buria, Leonardo M; Cornejo, Aydeé; Villanueva, Verónica D; West, Derek C

2011-02-08

402

18 CFR 420.51 - Hydroelectric power plant water use charges.  

Code of Federal Regulations, 2013 CFR

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...

2013-04-01

403

Removal of fluoride from water by five submerged plants.  

PubMed

Studies were conducted on the bioconcentration of fluoride (F(-)) in five submerged plants species. Ceratophyllum demersum, Hydrilla verticillata, Potamogeton malaianus, Myriophyllum verticillatum and Elodea nuttallii were all able to remove F(-) from water to some degree of efficiencies. At 5-20 mg F(-)/L culture solution, C. demersum had the best F(-)-removal performance, E. nuttallii had the poorest F(-)-removal performance among these plants. The relative growth rate (RGR) of the five species varied in different concentrations of F(-), of which C. demersum had the highest RGR. Its RGR decreased by 26.3 %, 63.2 % and 73.7 % from controls at 5, 10 and 20 mg F/L, respectively. PMID:22722597

Zhou, Jun; Gao, Jingqing; Liu, Yang; Ba, Kun; Chen, Shaohua; Zhang, Rinqin

2012-06-22

404

Life Cycle Assesment of Daugavgriva Waste Water Treatment Plant  

NASA Astrophysics Data System (ADS)

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.

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

2009-01-01

405

Energy conservation in water treatment: A study of four water treatment plants in Phoenix, Arizona  

SciTech Connect

The total annual energy cost for water supply in the city of Phoenix for the fiscal year 1980-81 was $7 million. Of this, energy costs for water treatment for the four water treatment plants serving the city was over 1 Million dollars. The study and research performed under this grant focuses on the energy cost saving opportunities in water treatment. Elements of major energy consuming functions in water treatment include electric motor-driven raw water pumps and treated water booster pumps, and electrical energy consumption from lighting, heating, ventilation, air conditioning and power driven process equipment. The objective of this project was to study the process and equipment used in water treatment, exclusive of booster pumping, and to identify cost saving alternatives. Both the analytical approaches as well as results are transferable to other urban areas. The research plan included the identification and analysis of existing water treatment methods and equipment for possible energy savings. It also included energy audits of building heating, ventilating and air-conditioning (HVAC) and lighting systems to identify energy conservation measures (ECM's). 8 figs., 20 tabs.

Not Available

1983-02-01

406

Decomposition in northern Minnesota peatlands  

SciTech Connect

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.

Farrish, K.W.

1985-01-01

407

Human pharmaceuticals, antioxidants, and plasticizers in wastewater treatment plant and water reclamation plant effluents.  

PubMed

The primary objective of this study was to determine the presence of unregulated organic chemicals in reclaimed water using complementary targeted and broad spectrum approaches. Eleven of 12 targeted human pharmaceuticals, antioxidants, and plasticizers, and 27 tentatively identified non-target organic chemicals, were present in secondary effluent entering tertiary treatment trains at a wastewater treatment plant and two water reclamation facilities. The removal of these compounds by three different tertiary treatment trains was investigated: coagulant-assisted granular media filtration (California Title-22 water, 22 CCR 60301-60357; Barclay [2006]), lime clarification/reverse osmosis (lime/ RO), and microfiltration-reverse osmosis (MF/RO). Carbamazepine, clofibric acid, gemfibrozil, ibuprofen, p-toluenesulfonamide, caffeine, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), and N-butyl benzenesulfonamide (N-BBSA) were present at low to high nanogram-per-liter levels in Title 22 water. The lime/RO product waters contained lower concentrations of clofibric acid, ibuprofen, caffeine, BHA, and N-BBSA (<10 to 71 ng/L) than their Title 22 counterparts. The MF/RO treatment reduced concentrations to levels below their detection limits, although BHT was present in MF/RO product water from one facility. The presence of the target analytes in two surface waters used as raw drinking water sources and a recharged groundwater was also examined. Surface waters used as raw drinking water sources contained caffeine, BHA, BHT, and N-BBSA, while recharged groundwater contained BHT, BHA, and N-BBSA. Nontarget compounds in recharged groundwater appeared to be attenuated with increased residence time in the aquifer. PMID:17370841

Soliman, Mary A; Pedersen, Joel A; Park, Heesu; Castaneda-Jimenez, Angelica; Stenstrom, Michael K; Suffet, I H Mel

2007-02-01

408

Purification of fuel and nitrate contaminated ground water using a free water surface constructed wetland plant  

SciTech Connect

Contaminated ground water from a former coke plant site was purified in a free water surface (FWS) constructed wetland plant during a 3-mo short-term experiment. The pilot plant (total surface area 27 m{sup 2}) was filled with a 1 m thick lava-gravel substrate planted with cattail (Typha spp.) and bulrush (Scirpus lacustrls). Major contaminants were low to moderate concentrations of polycyclic aromatic hydrocarbons, BTEX, nitrate, and nitrite. The wetland was dosed at hydraulic loading rates of q{sub A} = 4.8 and 9.6 cm d{sup {minus}1} with a hydraulic residence time (HRT) of 13.7 and 6.8 d. The surface removal rates of PAH were between 98.8 and 1914 mg m{sup {minus}2} d{sup {minus}1}. Efficiency was always {gt}99%. Extraction of lava gravel showed that approx. 0.4% of the applied PAH were retained on the substratum. The ratio of {Sigma}2,3-ring PAH and {Sigma}4,5,6-ring PAH showed a shift from 1:0.11 in water to 1:2.5 in lava. The removal of BTEX was {gt}99%, but might be in part due to volatilization. The efficiency in the removal of nitrate was 91% and of nitrite was 97%. Purification performance was not influenced by hydraulic loading rates or after die-back of the macrophytes.

Machate, T.; Heuermann, E.; Schramm, K.W.; Kettrup, A.

1999-10-01

409

Utilization of water hyacinths to upgrade heavily loaded waste-water treatment-plant effuents  

SciTech Connect

In recent years, considerable attention has been focused on the use of aquatic plants of various types to treat municipal wastewaters. While several species of plants have been found to be useful in this regard, water hyacinths appear to offer the most promise in areas where the climate is mild enough for them to flourish during most of the year. Accordingly, the primary purpose of this research was to test the acceptability of such systems for use in Southern States such as Alabama. A wastewater treatment plant located at Union Springs, Alabama was selected as the site for this study. The experimental water hyacinth system was configured as a set of two treatment trains with two growth channels in series for each train. One train was harvested and the other was not. Each growth channel was constructed of 3/4-inch marine plywood and was 8 feet wide, 2 feet deep and 32 feet long. The system was operated from May 1986 to October 1987. Observations from this study indicate that a water hyacinth treatment system can be a reliable method for upgrading secondary effluents to advance secondary levels in central Alabama. The reliable treatment period will extend from about May through December with no plant protection (possibly longer in Southern Alabama.)

McAnally, A.S.

1989-01-01

410

Onset of water stress, hysteresis in plant conductance, and hydraulic lift: Scaling soil water dynamics from millimeters to meters  

Microsoft Academic Search

Estimation of water uptake by plants and subsequent water stress are complicated by the need to resolve the soil-plant hydrodynamics at scales ranging from millimeters to meters. Using a simplified homogenization technique, the three-dimensional (3-D) soil water movement dynamics can be reduced to solving two 1-D coupled Richards' equations, one for the radial water movement toward rootlets (mesoscale, important for

Mario Siqueira; Gabriel Katul; Amilcare Porporato

2008-01-01

411

The effect of pH on plant litter decomposition and metal cycling in wetland mesocosms supplied with mine drainage  

Microsoft Academic Search

The long term effectiveness of compost-based wetland systems treating net-acidic mine waters is reliant upon a continuing supply of decomposed organic matter which provides the basic foodstock for sulphate reducing bacteria. The annual turnover of wetland vegetation within these systems has been suggested to be the primary source for this material once the original substrate has been consumed. This study

Lesley C. Batty; Paul L. Younger

2007-01-01

412

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

NASA Astrophysics Data System (ADS)

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.

Tardieu, F.

2012-04-01

413

Effect of water and salt stresses on the growth, gas exchange and water relations in Argyranthemum coronopifolium plants  

Microsoft Academic Search

Plants of Argyranthemum coronopifolium were submitted to water stress (preconditioned by watering every 3 days, two dry–wet cycles were imposed) and salt stress (15 days of exposure to 140 mm NaCl followed by a recovery period of 11 days), independently. Effects of water and salt stresses on gas exchange, water relations and growth parameters were investigated in order to know

F. De Herralde; C. Biel; R. Savé; M. A. Morales; A. Torrecillas; J. J. Alarcón; M. J. Sánchez-Blanco

1998-01-01

414

Parallel and serial applications of the RETRAN-03 power plant simulation code using domain decomposition and Krylov subspace methods  

Microsoft Academic Search

High-fidelity simulation of nuclear reactor accidents such as the rupture of a main steam line in a pressurized water reactor (PWR) requires three-dimensional core hydrodynamics modeling because of the strong effect channel cross flow has on reactor kinetics. A parallel nested Krylov linear solver was developed and implemented in the RETRAN-03 reactor systems analysis code to make such high-fidelity core

T. J. Downar; J. Y. Wu; J. Steill; R. Janardhan

1997-01-01

415

Effect of textile waste water on tomato plant, Lycopersicon esculentum.  

PubMed

In this study Sanganer town, Jaipur was selected as study area. The plants of Lycopersicon esculentum var. K 21(Tomato) treated with 20 and 30% textile wastewater were analyzed for metal accumulation, growth and biochemical parameters at per, peak and post flowering stages. Findings of the study revealed that chlorophyll content was most severely affected with the increase in metal concentration. Total chlorophyll content showed a reduction of 72.44% while carbohydrate, protein and nitrogen content showed a reduction of 46.83, 71.65 and 71.65% respectively. With the increase in waste water treatment the root and shoot length, root and shoot dry weight and total dry weight were reduced to 50.55, 52.06, 69.93, 72.42, 72.10% respectively. After crop harvesting, the fruit samples of the plants treated with highest concentration of textile waste water contained 2.570 mg g(-1)d.wt. of Zn, 0.800 mg g(-1) d.wt. Cu, 1.520 mg g(-1) d.wt. Cr and 2.010 mg g(-1) d.wt. Pb. PMID:23734449

Marwari, Richa; Khan, T I

2012-09-01

416

Decomposition Studies of Tertiarybutyldimethylantimony.  

National Technical Information Service (NTIS)

The vapor pressure, decomposition temperature, decomposition products, and decomposition reaction order are reported for a novel organometallic vapor-phase epitaxy (OMVPE) Sb precursor, tertiarybutyldimethylantimony (TBDMSb, C4H9(CH3)2Sb). The TBDMSb vapo...

C. H. Chen C. W. Hill D. S. Cao G. B. Stringfellow S. H. Li

1992-01-01

417

Growth stimulation of gram (Cicer arietinum) plant by water soluble carbon nanotubes.  

PubMed

Water soluble carbon nanotubes (wsCNTs) show enhancement of the growth rate of common gram (Cicer arietinum) plants. Treating plants with up to 6.0 ?g mL(-1) of wsCNT shows an increased growth rate in every part of the plant including the roots, shoots and also in branching. The noticeable difference between the wsCNT treated and controlled gram is the water uptake; in the former it is dramatically enhanced, suggesting better water absorption and retention related to enhanced growth. This work shows that unlike CNTs, wsCNTs are non-toxic to plant cells that conserve water transport in plants. PMID:21253651

Tripathi, Shweta; Sonkar, Sumit Kumar; Sarkar, Sabyasachi

2011-01-21

418

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

SciTech Connect

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.

NONE

1997-05-01

419

Translocation and metabolism of glycine betaine by barley plants in relation to water stress  

Microsoft Academic Search

The glycine betaine which accumulated in shoots of young barley plants (Hordeum vulgare L.) during an episode of water stress did not undergo net destruction upon relief of stress, but its distribution among plant organs changed. During stress, betaine accumulated primarily in mature leaves, whereas it was found mainly in young leaves after rewatering. Well-watered, stressed, and stressed-rewatered plants were

Juanita A. R. Ladyman; William D. Hitz; Andrew D. Hanson

1980-01-01

420

Plant response to the soil environment: An analytical model integrating yield, water, soil type, and salinity  

Microsoft Academic Search

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

Uri Shani; Alon Ben-Gal; Effi Tripler; Lynn M. Dudley

2007-01-01

421

N?Carboxymethylchitosan: Uptake and effect on chlorophyll production, water potential and biomass in tomato plants  

Microsoft Academic Search

Uptake and effects of water solutions of N?carboxymethylchitosan (NCMC) were determined in tomato plants under greenhouse conditions. Rapid uptake of NCMC occurred during the initial 12 hours of treatment and there was an increase of chlorophyl content in leaves of NCMC?treated plants. However, neither the water potential nor the biomass of test plants was influenced by NCMC treatments.

R. G. Cuero; G. Osuji; E. Duffus

1991-01-01

422

Capital cost functions of a surface water treatment plant and its components  

Microsoft Academic Search

The capital cost function of a surface water treatment plant has been estimated in a few past studies, of which the best known are a study by Orlob and Lindorf and another by Koenig. The present study presents an estimate of the capital cost function of a surface water treatment plant and estimates of the plant's major components which have

Hirohide Hinomoto

1977-01-01

423

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

ERIC Educational Resources Information Center

|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)|

Grenville, H. W.

1983-01-01

424

Mechanisms underlying plant resilience to water deficits: prospects for water-saving agriculture.  

PubMed

Drought is one of the greatest limitations to crop expansion outside the present-day agricultural areas. It will become increasingly important in regions of the globe where, in the past, the problem was negligible, due to the recognized changes in global climate. Today the concern is with improving cultural practices and crop genotypes for drought-prone areas; therefore, understanding the mechanisms behind drought resistance and the efficient use of water by the plants is fundamental for the achievement of those goals. In this paper, the major constraints to carbon assimilation and the metabolic regulations that play a role in plant responses to water deficits, acting in isolation or in conjunction with other stresses, is reviewed. The effects on carbon assimilation include increased resistance to diffusion by stomata and the mesophyll, as well as biochemical and photochemical adjustments. Oxidative stress is critical for crops that experience drought episodes. The role of detoxifying systems in preventing irreversible damage to photosynthetic machinery and of redox molecules as local or systemic signals is revised. Plant capacity to avoid or repair membrane damage during dehydration and rehydration processes is pivotal for the maintenance of membrane integrity, especially for those that embed functional proteins. Among such proteins are water transporters, whose role in the regulation of plant water status and transport of other metabolites is the subject of intense investigation. Long-distance chemical signalling, as an early response to drought, started to be unravelled more than a decade ago. The effects of those signals on carbon assimilation and partitioning of assimilates between reproductive and non-reproductive structures are revised and discussed in the context of novel management techniques. These applications are designed to combine increased crop water-use efficiency with sustained yield and improved quality of the products. Through an understanding of the mechanisms leading to successful adaptation to dehydration and rehydration, it has already been possible to identify key genes able to alter metabolism and increase plant tolerance to drought. An overview of the most important data on this topic, including engineering for osmotic adjustment or protection, water transporters, and C4 traits is presented in this paper. Emphasis is given to the most successful or promising cases of genetic engineering in crops, using functional or regulatory genes. as well as to promising technologies, such as the transfer of transcription factors. PMID:15475377

Chaves, M M; Oliveira, M M

2004-10-08

425

Water use and reuse opportunities and costs at oil shale plants. Volume 2  

SciTech Connect

Mining and processing of oil shale into fuels will consume large amounts of water and will vary from plant to plant. Variations in types of resources and the products produced will lead to a variety of mining and processing schemes each with their own water use patterns. This report describes several of these schemes, as well as their water use and waste water production patterns, water treatment plant designs, water costs, and opportunities for internal water reuse and recycling. This diversity leads to many waste water streams and a variety of opportunities for using low grade waters. This project analyzed the ways that water will be used, and may be reused in oil shale plants located in the Upper Colorado River Basin.

Heim, W.P.; Miller, C.

1983-09-20

426

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

SciTech Connect

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.

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

2009-04-03

427

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...

428

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...

429

Techniques and experimental approaches for the measurement of plant water status  

Microsoft Academic Search

Living cells need to be more or less saturated with water to function normally, but they are usually incomplete in this desirable condition. The two basic parameters which describe the degree of unsaturation, i.e. the plant water deficit are (i) the water content and (ii) the energy status of the water in the cell. The water content is usually expressed

Neil C. Turner

1981-01-01

430

Desert shrub water relations with respect to soil characteristics and plant functional type  

Microsoft Academic Search

Summary 1. Soil characteristics influence plant communities in part through water relations. Hypothetically, finer textured soils in arid climates should be associated with more negative plant and soil water potentials during drought, greater resistance of xylem to cavitation, and shallower root systems than coarse soils. 2. These hypotheses were tested by comparing the water relations of Great Basin shrubs growing

J. S. Sperry; U. G. Hacke

2002-01-01

431

Plant performance and water use of peppermint treated with methanol and glycine  

Microsoft Academic Search

Methanol applied to foliage has been reported to reduce water use of C3 crops. Two field experiments on peppermint measured both plant performance and soil water depletion for methanol, glycine, and an untreated control. No differences were found in dry matter yield, oil yield, plant height, leaf weight, or water use. Preliminary phytotoxicity studies showed no toxicity or necrosis at

Alan R. Mitchell; Fred J. Crowe; Marvin D. Butler

1994-01-01

432

Water use and reuse opportunities and costs at oil shale plants. Volume 2  

Microsoft Academic Search

Mining and processing of oil shale into fuels will consume large amounts of water and will vary from plant to plant. Variations in types of resources and the products produced will lead to a variety of mining and processing schemes each with their own water use patterns. This report describes several of these schemes, as well as their water use

W. P. Heim; C. Miller

1983-01-01

433

Operation, Maintenance and Performance Evaluation of the Potomac Estuary Experimental Water Treatment Plant. Main Volume.  

National Technical Information Service (NTIS)

The investigation evaluated the water quality produced by a 1.0 MGD demonstration water treatment plant (EEWTP), which was located adjacent to the Estuary at the Blue Plains WPCP (Water Pollution Control Plant), Washington, D.C. Based on certain hydrologi...

J. M. Montgomery

1983-01-01

434

Determination of threshold value of soil water content for field and vegetable plants with lysimeter measurements  

Microsoft Academic Search

Both the potential water consumption of plants and their ability to withdraw soil water are necessary in order to estimate actual evapotranspiration and to predict irrigation timing and amount. In relating to root water uptake the threshold value at which plants reducing evapotranspiration is an important parameter. Since transpiration is linearly correlated to dry matter production, under the condition that

S. Knoblauch

2009-01-01

435

[Effects of strip planting and fallow rotation on the soil and water loss and water use efficiency of slope farmland].  

PubMed

In order to enhance the soil water-retaining capacity of slope farmland and reduce its soil and water loss, a field study was conducted in 2007-2010 to examine the effects of strip planting and fallow rotation on the soil water regime, soil and water loss characteristics, and water use efficiency of a 10 degrees-15 degrees slope farmland in the arid area of southern Ningxia, Northwest China. Compared with the traditional no-strip planting, strip planting and fallow rotation increased the soil water content in 0-200 cm layer significantly, with an increment of 4.9% -7.0%. Strip planting and fallow rotation pattern could also effectively conserve the soil water in rain season, and obviously improve the soil water regime at crops early growth stages. As compared to no-strip planting, strip planting and fallow rotation increased the soil water content in 0-200 cm layer by 5.4%-8.5%, decreased the surface runoff by 0.7-3.2 m3 x hm(-2), sediment runoff by 0.2-1.9 t x hm(-2), and soil total N loss by 42.1% -73.3%, while improved the crop water use efficiency by 6.1% -24.9% and the precipitation use efficiency by 6.3% -15.3%. PMID:23189698

Hou, Xian-Qing; Li, Rong; Han, Qing-Fang; Jia, Zhi-Kuan; Wang, Wei; Yan, Bo; Yang, Bao-Ping

2012-08-01

436

Science Shorts: Gourd-ous Decomposition  

NSDL National Science Digital Library

While pumpkins are an iconic symbol in the classroom that represent fall, harvest time, and Halloween, they are also an ideal subject for teaching elementary students the fundamentals of scientific inquiry and plant decomposition. In a second-grade classr

Rubenstein, Amy; Siry, Christina; Cleary, Stacey

2009-09-01

437

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

PubMed Central

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.

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

2012-01-01

438

Mechanism of Cu(II)-catalyzed monochloramine decomposition in aqueous solution.  

PubMed

The decomposition of monochloramine, which is commonly used as a secondary disinfectant at water treatment plants to reduce the formation of disinfection byproducts, always occurs in water and can be accelerated by certain catalytic substances. This work was to investigate the mechanism of monochloramine decomposition catalyzed by Cu(II) in aqueous solution. Ultraviolet (UV) spectral results showed that either Cu(II) addition or pH decrease would significantly promote the transformation of monochloramine to dichloramine. A copper intermediate, Cu(I), was extracted from the NH(2)Cl-Cu(II) solution by solid-phase extraction and identified by X-ray photoelectron spectroscopy (XPS). Electron spin resonance (ESR) results showed that hydroxyl radical (.OH) and amidogen radical (.NH(2)) were generated in the reaction between monochloramine and Cu(II). These radical intermediates also contributed to monochloramine decomposition. Based on the experimental results, the reaction mechanism for Cu(II)-catalyzed monochloramine decomposition was proposed which consisted of two pathways: 1) direct catalysis in which Cu(II) acts as a Lewis acid to accelerate monochloramine decomposition to dichloramine (major pathway); and 2) indirect catalysis in which the active radical intermediates (.OH and .NH(2)) react with monochloramine and lead to its decomposition (minor pathway). PMID:19345982

Fu, Jun; Qu, Jiuhui; Liu, Ruiping; Qiang, Zhimin; Zhao, Xu; Liu, Huijuan

2009-04-05

439

WATER NUTRIENTS, PLANT NUTRIENTS, AND INDICATORS OF BIOLOGICAL CONTROL IN WATERHYACINTH AT TEXAS FIELD SITES.  

Technology Transfer Automated Retrieval System (TEKTRAN)

Interactions occur under controlled conditions between the nutrient content of floating waterhyacinth plants (Eichhornia crassipes) and reporduction of waterhyacinth weevils (Neochetina bruchi and N. eichhorniae) introduced for biocontrol. Few studies have linked water nutrition, plant nutrition, a...

440

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 ...

441

Plant species distribution in relation to water-table depth and soil ...  

Treesearch

International Institute of Tropical Forestry ... Title: Plant species distribution in relation to water-table depth and soil redox potential in ... riparian plant communities¡ªdefined as wet, moist, and dry meadow¡ªalong short topographic gradients.

442

Effects of NaCl salinity and water stress on growth and leaf water relations of Asteriscus maritimus plants  

Microsoft Academic Search

Potted plants of Asteriscus maritimus (L.) Less were submitted to water stress (during two consecutive cycles, irrigation water was withheld for 5 days followed by a recovery period of 25 days) and saline stress (150 days of exposure to 0, 70 and 140mM NaCl daily irrigation) in order to assess the effect on leaf water relations and growth parameters. Plants

P. Rodr??guez; A. Torrecillas; M. A. Morales; M. F. Ortuño; M. J. Sánchez-Blanco

2005-01-01

443

SOLAR CONVERSION AND ENERGY STORAGE BY THE CHLOROPHYLL A DIHYDRATE PHOTOCATALYTIC DECOMPOSITION OF WATER AND REDUCTION OF CARBON-DIOXIDE  

Microsoft Academic Search

In this work the photoconversion and storage of visible light energy based on the half-cell reactions of water photolysis by crystalline chlorophyll a dihydrate is described. The role of water on the photochemical activity of chlorophyll a is examined by a study of a photogalvanic cell consisting of a Pt\\/Chl a photocathode and a Chl a-free anode. The production of

DANIEL RAY FRUGE

1980-01-01

444

Photocatalytic decomposition of water–methanol solution over metal-doped layered perovskites under visible light irradiation  

Microsoft Academic Search

In search for efficient photocatalysts for water splitting under visible light, the effect of cation substitution on a layered perovskite, La2Ti2O7 has been studied. Among various types of dopants, only Cr and Fe showed intense absorption in the visible light region (?>420nm), over which H2 was produced photocatalytically from water–methanol solution. XPS measurements indicated that the oxidation state of doped

Dong Won Hwang; Hyun Gyu Kim; Jum Suk Jang; Sang Won Bae; Sang Min Ji; Jae Sung Lee

2004-01-01

445

Effects of potassium deficiency on water relations and photosynthesis of the tomato plant  

Microsoft Academic Search

Potassium deficient (?K) and potassium sufficient (+K) plants were exposed to four days of water stress. Well watered ?K and\\u000a +K plants had comparable rates of transpiration. But +K plants had a larger leaf area and depleted the soil moisture to a\\u000a greater extent on day 1 of stress. For days 2 and 3 their transpiration rate, leaf water potential

M. H. Behboudian; D. R. Anderson

1990-01-01

446

Field validation of isotopic procedures for determining sources of water used by plants in a semi-arid environment  

Microsoft Academic Search

Methods for using stable isotopes of water (2H, 18O) for determining the sources of water transpired by plants in a semi-arid field situation are validated. A comparison of the isotopic composition of the soil water in zones of high soil water potential (and hence high plant water availability) with that in plants shows that the overall approach is subject to

Jean-Pierre Brunel; Glen R. Walker; Ashleigh K. Kennett-Smith

1995-01-01

447

Corrosion of thermal power plant chemical water treatment equipment under conditions of physical-chemical tertiary treatment of municipal wastewater  

Microsoft Academic Search

Steam power plants are among the largest users of fresh water. Therefore, the use of treated municipal water is of great importance. One of the primary factors to be considered in determining the feasibility of using municipal water at a thermal power plant is the rate of corrosion. The water leaving the municipal treatment plant differs from naturally occurring water

K. M. Abdullaev; I. A. Malakhov; M. S. Trifel; A. K. Khachaturov; B. S. Azimov

1982-01-01

448

Water quality investigation of Kingston Fossil Plant dry ash stacking  

SciTech Connect

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.

Bohac, C.E.

1990-04-01

449

Spatial decomposition and assignment of infrared spectra of simple ions in water from mid-infrared to THz frequencies: Li(+)(aq) and F(-)(aq).  

PubMed

Ionic hydration is of fundamental relevance from chemical reactivity in aqueous solution to biomolecular function at physiological conditions. Vibrational spectroscopy belongs to the most widely used experimental methods in studies of solvation phenomena. There is, however, still limited molecular understanding as to how the vibrational response of solutions is modulated by the presence of solvation shells around solutes, i.e., by interfacial water. Liquid-state THz spectroscopy has been demonstrated to be able to detect even small solute-induced changes of the hydrogen bond dynamics at the solute-water interface. In many cases it reveals rather long-ranged dynamical correlations around solutes, involving many solvent molecules, that can be tackled theoretically by analyzing vibrational spectra in a distance-resolved manner. Here, several spatial decomposition schemes for infrared spectra are used to reveal the distinct distance- and frequency-dependent contributions of the solvation shells to the spectral response in aqueous solutions of Li(+) and F(-). The importance of an explicit representation of the solute's electronic structure for the proper description of solute-solvent polarization effects is demonstrated. The solvent's response to the presence of the solute is systematically disentangled and reveals important differences between the spectral responses due to intra- and intermolecular motion as probed in the mid- and far-infrared spectral windows, respectively. PMID:23822313

Smiechowski, Maciej; Forbert, Harald; Marx, Dominik

2013-07-01

450

Spatial decomposition and assignment of infrared spectra of simple ions in water from mid-infrared to THz frequencies: Li+(aq) and F-(aq)  

NASA Astrophysics Data System (ADS)

Ionic hydration is of fundamental relevance from chemical reactivity in aqueous solution to biomolecular function at physiological conditions. Vibrational spectroscopy belongs to the most widely used experimental methods in studies of solvation phenomena. There is, however, still limited molecular understanding as to how the vibrational response of solutions is modulated by the presence of solvation shells around solutes, i.e., by interfacial water. Liquid-state THz spectroscopy has been demonstrated to be able to detect even small solute-induced changes of the hydrogen bond dynamics at the solute-water interface. In many cases it reveals rather long-ranged dynamical correlations around solutes, involving many solvent molecules, that can be tackled theoretically by analyzing vibrational spectra in a distance-resolved manner. Here, several spatial decomposition schemes for infrared spectra are used to reveal the distinct distance- and frequ