Sample records for water decomposition plant

  1. Nuclear driven water decomposition plant for hydrogen production

    NASA Technical Reports Server (NTRS)

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

    1976-01-01

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

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

    PubMed

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

    2013-01-01

    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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  4. Phlogopite Decomposition, Water, and Venus

    NASA Technical Reports Server (NTRS)

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

    2005-01-01

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

  5. Fast Construction of Plant Architectural Models Based on Substructure Decomposition

    Microsoft Academic Search

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

    2003-01-01

    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

  6. Ozone decomposition in water solutions 

    E-print Network

    Hewes, Cecil Grayson

    1969-01-01

    . . . . . . . . . . . . . 75 III. CBI. iiICAT, OXYGEN DEMAND TEST. . IV. OIONE DECOI'IPOSITION DATA. . . . . V. COD DATA FOH THE CONTINUOUS ABSOHBER- REACTION SYSTEM VITA 78 8$ LIST OF TABLES TABI E PAGE I. OZONE DECOMPOSITION IN MATER SOLUTIONS. . . g4 Il. REACTION...ATER SOLUTIONS OF pH 8. XIII. REACTION RATE CONSTANTS FOR THE D'COMPOSITION OF OZONE IN INTER SOLUTIONS OF pH 8. XIV COD REMOVAL BY OZONE XV. OZONIZATION OF MATER CONTAINIiNG RESIDUAL AMINE. 57 60 LIST OF FIGURES FIGURE 1. FIOW DIAGRAM OF THZ...

  7. Proximate nutritive value changes during decomposition of salt marsh plants

    Microsoft Academic Search

    Armando A. Cruz

    1975-01-01

    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

  8. Plant Water Relations

    NSDL National Science Digital Library

    Jim Bidlack

    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.

  9. Hydrogen production by the decomposition of water

    SciTech Connect

    Bowman, M.G.; Hollabaugh, C.M.

    1981-01-13

    How to produce hydrogen from water was a problem addressed by this invention. The solution employs a combined electrolyticalthermochemical sulfuric acid process. Additionally, high purity sulfuric acid can be produced in the process. Water and SO2 react in electrolyzer (12) so that hydrogen is produced at the cathode and sulfuric acid is produced at the anode. Then the sulfuric acid is reacted with a particular compound mrxs so as to form at least one water insoluble sulfate and at least one water insoluble oxide of molybdenum, tungsten, or boron. Water is removed by filtration; and the sulfate is decomposed in the presence of the oxide in sulfate decomposition zone (21), thus forming SO3 and reforming mrxs. The mrxs is recycled to sulfate formation zone (16). If desired, the SO3 can be decomposed to SO2 and O2; and the SO2 can be recycled to electrolyzer (12) to provide a cycle for producing hydrogen.

  10. Effect of water level drawdown on decomposition in boreal peatlands

    NASA Astrophysics Data System (ADS)

    Straková, Petra; Penttilä, Timo; Laiho, Raija

    2010-05-01

    Plant litter production and decomposition are key processes in element cycling in most ecosystems. In peatlands, there has been a long-term imbalance between litter production and decay caused by high water levels (WL) and consequent anoxia. This has resulted in peatlands being a significant sink of carbon (C) from the atmosphere. However, peatlands are experiencing both "natural" (global climate change) and anthropogenic (ditching) changes that threaten their ability to retain this ecosystem identity and function. Many of these alterations can be traced back to WL drawdown, which can cause increased aeration, higher acidity, falling temperatures, and a greater probability of drought. Such changes are also associated with an increasing decomposition rate, and therefore a greater amount of C released back to the atmosphere. Yet studies about how the overall C balance of peatlands will be affected have come up with conflicting conclusions, demonstrating that the C store could increase, decrease, or remain static. A factor that has been largely overlooked is the change in litter type composition following persistent WL drawdown. It is the aim of our study, then, to help to resolve this issue. We studied the effects of short-term (ca. 4 years) and long-term (ca. 40 years) persistent WL drawdown on the decomposition of numerous types of above-ground and below-ground plant litters at three boreal peatland sites: bog, oligotrophic fen and mesotrophic fen. We thus believe that enough permutations have been created to obtain a good assessment of how each factor, site nutrient level, WL regime, and litter type composition, influences decomposition. We used the litter bag method to measure the decomposition rates: placed measured amounts of plant litter, or cellulose strips as a control, into closed mesh bags, and installed the bags in the natural environment for decomposition for each litter type for varying amounts of time. Following litter bag recovery, the litter was cleaned of excess debris and analyzed for changes in mass, enzyme activity, mesofauna presence, and microbial community composition, among other things. The experiment has a run-time of ten years, the results from the first two years are presented in the poster.

  11. Tremolite Decomposition and Water on Venus

    NASA Technical Reports Server (NTRS)

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

    2000-01-01

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

  12. Decomposition of petroleum products in our natural waters

    Microsoft Academic Search

    L. R. Brown; R. G. Tischer

    1969-01-01

    The overall objective of this investigation was to study the decomposition of crude and refined petroleum products in our natural waters. More specifically, the aims of this proposal were (1) to investigate the physical, chemical, and microbiological changes that occur in fresh and brackish water environments during the decomposition of crude and refined petroleum products and (2) to investigate the

  13. Water Desalination Plant

    NSDL National Science Digital Library

    Integrated Teaching and Learning Program,

    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.

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

    E-print Network

    Tennessee, University of

    is an important driver of carbon and nutrient cycling, and is either directly or indirectly controlledWhat drives plant litter decomposition globally? Ecological Monographs? Carri J. LeRoy1,2,3 , Dylan and Evolutionary Biology, University of Tennessee, Knoxville, TN 37996 #12;Abstract - 268 Global leaf

  15. Plant Water Relations.

    ERIC Educational Resources Information Center

    Tomley, David

    1982-01-01

    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)

  16. Does accelerated soil organic matter decomposition in the presence of plants increase plant N availability?

    Microsoft Academic Search

    Feike A. Dijkstra; Nicholas E. Bader; Dale W. Johnson; Weixin Cheng

    2009-01-01

    Plant roots can increase microbial activity and soil organic matter (SOM) decomposition via rhizosphere priming effects. It is virtually unknown how differences in the priming effect among plant species and soil type affect N mineralization and plant uptake. In a greenhouse experiment, we tested whether priming effects caused by Fremont cottonwood (Populus fremontii) and Ponderosa pine (Pinus ponderosa) grown in

  17. Effect of salinity and plant species on CO 2 flux and leaching of dissolved organic carbon during decomposition of plant residue

    Microsoft Academic Search

    M. W. Olsen; R. J. Frye; E. P. Glenn

    1996-01-01

    Mitigation of increased concentrations of CO2 in the atmosphere by plants may be more efficient in saline systems with soils lower in organic matter than in other freshwater systems. In saline systems, decomposition rates may be lower and potential soil carbon storage higher than in fresh water systems. The effects of salinity, plant species and time on CO2 surface flux

  18. Decomposition of Carex and Nuphar plants in a subalpine marsh

    Microsoft Academic Search

    Jae Geun Kim

    2001-01-01

    To assess the effect of water depth on the decomposition process, I measured the losses in dry mass of the above- and belowground\\u000a materials ofCarex utriculata andNuphar luteum ssp.potysepalum as well as cellulose (Whatman filter paper) in the top 10 cm of sediment\\/soil in a subalpine marsh. Samples were examined\\u000a by the litter bag technique at three flooding levels (0

  19. Decomposition of Plant Debris by the Nematophagous Fungus ARF

    PubMed Central

    Wang, Kening; Riggs, R. D.; Crippen, Devany

    2004-01-01

    In the study of the biological control of plant-parasitic nematodes, knowledge of the saprophytic ability of a nematophagous fungus is necessary to understand its establishment and survival in the soil. The objectives of this study were (i) to determine if the nematophagous fungus ARF (Arkansas Fungus) shows differential use of plant residues; and (ii) to determine if ARF still existed in the soil of a field in which ARF was found originally and in which the population level of Heterodera glycines had remained very low, despite 15 years of continuous, susceptible soybean. Laboratory studies of the decomposition of wheat straw or soybean root by ARF were conducted in two separate experiments, using a CO? collection apparatus, where CO?-free air was passed through sterilized cotton to remove the microorganisms in the air and then was passed over the samples, and evolved CO? was trapped by KOH. Milligrams of C as CO? was used to calculate the percentage decomposition of the plant debris by ARF. Data indicated ARF decomposed 11.7% of total organic carbon of the wheat straw and 20.1% of the soybean roots in 6 weeks. In the field soil study, 21 soil samples were taken randomly from the field. Only 3 months after the infestation of the soil with H. glycines, the percentage of parasitized eggs of H. glycines reached 64 ± 19%, and ARF was isolated from most parasitized eggs of H. glycines. Research results indicated ARF could use plant residues to survive. PMID:19262814

  20. Photocatalytic decomposition of water on spontaneously hydrated layered perovskites

    Microsoft Academic Search

    Tsuyoshi Takata; Yoko Furumi; Michikazu Hara; Akira Tanaka; Junko N. Kondo; Kazunari Domen

    1997-01-01

    The photocatalytic decomposition of water was achieved on ion-exchangeable layered perovskites. Photons are absorbed in the perovskite layers containing Ti{sup 4+}\\/Nb{sup 5+} cations to generate photoexcited conduction electrons and valence holes. These electrons and holes reduce HâO into Hâ and oxidize into Oâ, respectively. 15 refs., 2 figs., 1 tab.

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

    Microsoft Academic Search

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

    2001-01-01

    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

  2. Plant Hormones and Water Stress

    Microsoft Academic Search

    Y. Vaadia

    1976-01-01

    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

  3. Kinetics of the pyrolytic and hydrothermal decomposition of water hyacinth.

    PubMed

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

    2011-07-01

    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

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

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

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

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

    Microsoft Academic Search

    Bernard M. Kabyemela; Tadafumi Adschiri; Roberto M. Malaluan; Kunio Arai

    1999-01-01

    The authors are developing a new catalyst-free process of cellulose decomposition in supercritical water. In their initial study on the cellulose decomposition in supercritical water, the main products of cellulose decomposition were found to be oligomers of glucose (cellobiose, cellotriose, etc.) and glucose at short residence times (400 C, 25 MPa, 0.05 s). The kinetics of glucose at these conditions

  6. Researching power plant water recovery

    SciTech Connect

    NONE

    2008-04-01

    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.

  7. North City Water Reclamation Plant

    E-print Network

    Prevedouros, Panos D.

    North City Water Reclamation Plant Maja Caroee Diana Lee Niko Salvador #12;What is Water Reclamation? Water Reclamation is the process of treating wastewater to be suitable for reuse Not Suitable Planning for Water Reclamation ProgramPlanning for Water Reclamation Program Late 1980's Construction began

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

    PubMed

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

    2001-03-19

    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

  9. Decomposition of Glycerine by Water Plasmas at Atmospheric Pressure

    NASA Astrophysics Data System (ADS)

    Takayuki, Watanabe; Narengerile

    2013-04-01

    High concentration of aqueous glycerine was decomposed using a direct current (DC) plasma torch at atmospheric pressure. The torch can generate the plasma with water as the plasma-supporting gas in the absence of any additional gas supply system and cooling devices. The results indicated that 5 mol% glycerine was completely decomposed by water plasmas at arc powers of 0.55~1.05 kW. The major products in the effluent gas were H2 (68.9%~71.1%), CO2 (18.9%~23.0%), and CO (0.2%~0.6%). However, trace levels of formic acid (HCOOH) and formaldehyde (HCHO) were observed in the liquid effluent. The results indicated that the water plasma waste treatment process is capable of being an alternative green technology for organic waste decomposition.

  10. Kinetics of Heterogeneous Catalytic Ozone Decomposition in Water on an Activated Carbon

    Microsoft Academic Search

    Fernando J. Beltrán; J. Rivas; P. Álvarez; R. Montero-de-Espinosa

    2002-01-01

    Ozone decomposition in water in the presence of an activated carbon has been studied. Variables investigated were agitation speed, carbon particle size, temperature and pH. In all cases, the presence of activated carbon improved the ozone decomposition rate. Between pH 2 and 7 the ozone decomposition rate due to both the homogeneous and heterogeneous mechanisms hardly varied while a significant

  11. Ozone decomposition and benzene oxidation catalysts based on iron and manganese oxides as industrial wastes from water decontamination by ozone treatment

    Microsoft Academic Search

    L. A. Zaloznaya; S. N. Tkachenko; G. V. Egorova; I. S. Tkachenko; A. V. Sobolev; E. Z. Golosman; V. A. Troshina; V. V. Lunin

    2009-01-01

    Effective ozone decomposition catalysts were created on the basis of iron oxides as side products from natural water treated\\u000a with ozone at water treatment plants. Iron oxide catalysts doped with manganese oxide are by 40% more active in benzene oxidation.\\u000a These iron-manganese catalysts can be recommended for industrial manufacture by the designed technologies and application\\u000a in ozone decomposition and benzene

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

    PubMed

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

    2015-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

  14. Water Filtration Using Plant Xylem

    E-print Network

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

    2013-01-01

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

  15. Water Filtration Using Plant Xylem

    PubMed Central

    Chambers, Valerie; Venkatesh, Varsha; Karnik, Rohit

    2014-01-01

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

  16. Predictive control of water supply plant

    Microsoft Academic Search

    Boris AzeniC; Nedjeljko PeriC; D. Sliskovic

    2002-01-01

    This paper deals with the possibility of applying predictive control for water level control in tanks of water supply plants. The proposed control system includes a ground water intake plant; water treatment plant and water tanks. Since predictive controllers are based on mathematical models of controlled processes, the mathematical model of a water supply plant has been created for the

  17. Decomposition

    USGS Publications Warehouse

    Middleton, Beth A.

    2014-01-01

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

  18. Improve plant water quality

    Microsoft Academic Search

    1983-01-01

    Producing high quality water for various inplant usages reliably and cost efficiently is of prime concern. DuPont's Beaumont Works is no exception. The production of ammonia, aniline, acrylonitrile, methanol, tetraethyl lead, and various proprietary products requires high quality water for boiler water makeup, cooling tower makeup, and various process systems. In addition, potable water is produced. For the past nine

  19. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  1. Water Filtration Using Plant Xylem

    E-print Network

    Boutilier, Michael Stephen Ha

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

  2. Power Plant Water Intake Assessment.

    ERIC Educational Resources Information Center

    Zeitoun, Ibrahim H.; And Others

    1980-01-01

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

  3. Transpiration - Water Movement through Plants

    NSDL National Science Digital Library

    This lesson and its animation follows the journey of water through a plant from its uptake by roots to its evaporation from the leaf surface. How this journey is altered by plant characteristics such as stomata and cuticles as well as by changes in the environment will be described.

  4. Transpiration: Water Movement Through Plants

    NSDL National Science Digital Library

    Tracy Sterling (New Mexico State University; )

    2005-09-23

    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.

  5. Interactions between decomposition of plant residues and nitrogen cycling in soil

    Microsoft Academic Search

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

    1996-01-01

    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

  6. Soil animals alter plant litter diversity effects on decomposition

    PubMed Central

    Hättenschwiler, Stephan; Gasser, Patrick

    2005-01-01

    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

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

    Microsoft Academic Search

    F. A. Dijkstra; W. Cheng

    2005-01-01

    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

  8. 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...

  9. Seasonal decomposition of Typha latifolia in a free-water surface constructed wetland

    Microsoft Academic Search

    Juan A. Álvarez; Eloy Bécares

    2006-01-01

    Litter decomposition has important consequences on constructed wetlands because it is related to the autochthonous production of organic matter, clogging rates in surface-flow wetlands, and terrestrialization in free-water surface wetlands. Decomposition rates of Typha latifolia were quantified during both winter and summer in a free-water surface constructed wetland using the litter bag technique. Air-dried leaves and stems of Typha were

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

    Microsoft Academic Search

    E. Kristensen

    1994-01-01

    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

  11. The effect of living plants on root decomposition of four grass species

    Microsoft Academic Search

    Krift van der T. A. J; Peter J. Kuikman; Frank Berendse

    2002-01-01

    We tested whether living plant roots of Holcus lanatus and Festuca ovina can affect the decomposition rate of dead roots of Holcus lanatus, Festuca rubra, Anthoxanthum odoratum and Festuca ovina. Moreover, we investigated whether this effect is dependent on the decomposing root species or the nitrogen supply during the growth of the roots. The selected perennial grass species are typical

  12. Plant Leaf Residue Decomposition, Nutrient Release and Soil Enzyme Activity

    Microsoft Academic Search

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

    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

  13. Effect of submerged plant Potamogeton crispus on the concentrations of phosphorus fractions in overlying water

    Microsoft Academic Search

    Lizhi Wang; Guoxiang Wang; Zhenfei Yu; Xiankun Gu; Qiumin Chen

    2010-01-01

    The effect of submerged plant P. crispus on the concentrations of phosphorus (P) fractions in overlying water and seasonal variation were investigated under simulating condition. The growth and decomposition of P. crispus were discussed. The mechanism of the P exchange at sediment-water interface in shallow lake was elucidated ulteriorly. The results indicated that dissolved total P (DTP) was the dominated

  14. Effect of Water Vapor on Benzene Decomposition Using a Nonthermal-Discharge Plasma Reactor

    Microsoft Academic Search

    Atsushi Ogata; Noboru Shintani; Kazushi Yamanouchi; Koichi Mizuno; Satoshi Kushiyama; Toshiaki Yamamoto

    2000-01-01

    The effect of water vapor on benzene decomposition in air was investigatedusing a nonthermal-discharge plasma reactor packed with ferroelectricmaterials. The conversion of benzene was found to decrease with an increaseof water concentration. On the other hand, the selectivity to CO2 in thedecomposition products increased with an increase of water concentration. Acomparison between the benzene conversion to CO and CO2 suggested

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

    E-print Network

    Cai, Xiao-Chuan

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

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

    E-print Network

    Pázsit, Imre

    Noise Decomposition in Boiling Water Reactors with Application to Stability Monitoring J. Karlsson in boiling water reactor (BWR) noise measure- ments, based on flux factorization techniques (i.e., using reactors4 or flux oscillations in boiling water reactors5,6 ~BWRs!. In these cases the different modes have

  17. On the thermal decomposition and residue formation of plant oils

    SciTech Connect

    Goettler, H.J.; Harwood, R.F.; Ziejewski, M.; Klosterman, H.J.

    1986-01-01

    Plant oils are considered viable replacement fuels for diesel engines. However, in order to become successful, diesel fuel substitutes, problems associated with the formation of lacquer and carbon deposits on engine components must be resolved, else truly long-term engine reliability will not be possible. This paper reports some basic experiments into the formation of residues due to liquid phase reactions of a number of plant oils as a function of temperature.

  18. Quality assessment of plant transpiration water

    NASA Technical Reports Server (NTRS)

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

    1990-01-01

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

  19. Water Treatment Technology - General Plant Operation.

    ERIC Educational Resources Information Center

    Ross-Harrington, Melinda; Kincaid, G. David

    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…

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

    NASA Astrophysics Data System (ADS)

    Gill, A. L.; Finzi, A.

    2014-12-01

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

  1. A Modal Decomposition of the Rotating Shallow Water Equations

    NASA Astrophysics Data System (ADS)

    Poulin, Francis; Waite, Michael; Greig, Daniel

    2013-04-01

    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.

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

    DOEpatents

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

    1983-02-08

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

  3. Variation in decomposition rates in the fynbos biome, South Africa: the role of plant species and plant stoichiometry

    PubMed Central

    Janion, Charlene; Chown, Steven L.; Leinaas, Hans Petter

    2010-01-01

    Previous studies in the fynbos biome of the Western Cape, South Africa, have suggested that biological decomposition rates in the fynbos vegetation type, on poor soils, may be so low that fire is the main factor contributing to litter breakdown and nutrient release. However, the fynbos biome also comprises vegetation types on more fertile soils, such as the renosterveld. The latter is defined by the shrub Elytropappus rhinocerotis, while the shrub Galenia africana may become dominant in overgrazed areas. We examined decomposition of litter of these two species and the geophyte Watsonia borbonica in patches of renosterveld in an agricultural landscape. In particular, we sought to understand how plant species identity affects litter decomposition rates, especially through variation in litter stoichiometry. Decomposition (organic matter mass loss) varied greatly among the species, and was related to litter N and P content. G. africana, with highest nutrient content, lost 65% of its original mass after 180 days, while E. rhinocerotis had lost ca. 30%, and the very nutrient poor W. borbonica <10%. Litter placed under G. africana decomposed slightly faster than when placed under E. rhinocerotis. Over the course of the experiment, G. africana and E. rhinocerotis lost N and P, while W. borbonica showed strong accumulation of these elements. Decomposition rates of G. africana and E. rhinocerotis were substantially higher than those previously reported from fynbos vegetation, and variation among the species investigated was considerable. Our results suggest that fire may not always be the main factor contributing to litter breakdown and nutrient release in the fynbos biome. Thus, biological decomposition has likely been underestimated and, along with small-scale variation in ecosystem processes, would repay further study. Electronic supplementary material The online version of this article (doi:10.1007/s00442-010-1753-7) contains supplementary material, which is available to authorized users. PMID:20827492

  4. 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...

  5. Response of plants to water stress

    PubMed Central

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

    2014-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Choi, S.; Watanabe, T.

    2012-12-01

    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.

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

    PubMed

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

    2013-06-01

    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

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

    E-print Network

    Roca, Rémy

    Scale decomposition of atmospheric water budget over West Africa during the monsoon 2006 from NCEP the terms of the atmospheric water budget over West Africa using a dedicated decomposition methodology scales of seasonal mean precipitation and moisture flux divergence over West Africa during the monsoon

  9. Water protection in coke-plant design

    SciTech Connect

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

    2009-07-15

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

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

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

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

  11. Hydroxide decomposition of dimethylsulfoniopropionate to form dimethylsulfide. [in sea water

    NASA Technical Reports Server (NTRS)

    Dacey, John W. H.; Blough, Neil V.

    1987-01-01

    The kinetics of DMS production resulting from reaction of OH(-) with DMSP were investigated as a function of hydroxide concentration and temperature. The reaction was first-order with respect to DMSP and OH(-). The second order rate constant at 20+/-1 C is 0.0044/M/sec. The activation energy for this reaction is 14.4 kcal/mode. The investigation indicates that the rate of reaction of DMSP with OH(-) is very slow at the pH of seawater, suggesting that DMSP, which may be a major precursor of DMS in seawater, decomposes in the ocean by other mechanisms. A bacterium which produces DMS from DMSP quantitatively at rates many orders of magnitude higher than indicated by OH(-1) decomposition has been cultured, suggesting that enzymatic processes accelerate the production of DMS from DMSP in seawater.

  12. A Two-Phase Decomposition Method for Optimal Design of Looped Water Distribution Networks

    Microsoft Academic Search

    Okitsugu Fujiwara; Do Ba Khang

    1990-01-01

    A two-phase decomposition method is proposed for the optimal design of new looped water distribution networks as well as for the parallel expansion of existing ones. The main feature of the method is that it generates a sequence of improving local optimal solutions. The first phase of the method takes a gradient approach with the flow distribution and pumping heads

  13. Find Out How Plants Use Water

    NSDL National Science Digital Library

    2013-04-10

    In this activity, learners investigate how plants use water. By making the flowers change color, learners see how water moves up the stem to the leaves and the flowers. Use this activity to discuss the structure of plants and the nutrients they need to survive. Safety note: young learners should get an adult to help them trim the stems of the flowers.

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

    NASA Technical Reports Server (NTRS)

    Funk, J. E.

    1977-01-01

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

  15. Decomposition of cellulose to produce 5-hydroxymethyl-furaldehyde in subcritical water

    Microsoft Academic Search

    Huisheng Lü; Xiangke Li; Minhua Zhang

    2008-01-01

    A method for decomposition of cellulose to produce 5-hydroxymethyl-furaldehyde (5-HMF) in subcritical water-carbon dioxide\\u000a binary system was proposed. A series of experiments were performed in a batch reaction vessel. Main products of the decomposition\\u000a of cellulose are 5-HMF, furfural, levulinic acid and 1, 2, 4-benzenetriol. The optimum condition for the preparation of 5-HMF\\u000a was found as 523.15 K, 5.0% carbon

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

    PubMed Central

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

    2014-01-01

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

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

    PubMed

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

    2013-03-28

    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

  18. New aspects of heterogeneous photocatalysts for water decomposition

    Microsoft Academic Search

    Kazunari Domen; Michikazu Hara; Junko N. Kondo; Tsuyoshi Takata; Akihiko Kudo; Hisayoshi Kobayashi; Yasunobu Inoue

    2001-01-01

    Several new photocatalysts for overall water splitting are described. Under UV light irradiation (270 nm), La-doped NaTaO3 modified with NiO decomposed water into H2 and O2 with extremely high quantum efficiency. Under an optimized condition, the apparent quantum efficiency, which was estimated\\u000a with numbers of irradiated photons and evolved H2 molecules, reached 56%. New stable photocatalytic materials containing elements with

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

    NASA Astrophysics Data System (ADS)

    Opsahl, Stephen; Benner, Ronald

    1995-12-01

    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.

  20. Role of Plants in Water Filtration

    NSDL National Science Digital Library

    This experiment will help students to understand the role of plants in filtering the water moving through a watershed. Students will discover that soil and plants have something of a dual role in this process and, depending on whether materials are dissolved or suspended in the water, soils and plant roots can remove some or all of this material as the water moves down through soil. They also learn that most suspended materials will adhere to the soil and these may then be broken down and used as food by the plants. This experiment is a very simplified way to show whether plants will take up certain kinds of materials from water moving relatively quickly through their root systems.

  1. A Trip to the Water Plant.

    ERIC Educational Resources Information Center

    Laskey, Marilyn

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

  2. Water retention capacity of tissue cultured plants

    Microsoft Academic Search

    Klerk de G. J. M; F. Wijnhoven

    2005-01-01

    Leaves rapidly close their stomata after detachment resulting in a strong reduction of water loss. It has been reported that detached leaves of in vitro produced plants show continuous water loss indicating that they are unable to close the stomata properly and\\/or that their cuticle is malfunctioning. We examined the water retention capacity (WRC) of detached primary leaves of in

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

    Microsoft Academic Search

    Wolfgang Kundt; Eva Gruber

    2006-01-01

    There is a correspondence between the circulation of blood in all higher animals and the circulation of sap in all higher plants - up to heights h of 140 m - through the xylem and phloem vessels. Plants suck in water from the soil, osmotically through the roothair zone, and subsequently lift it osmotically again, and by capillary suction (via

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

    PubMed Central

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

    2013-01-01

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

  5. Synthesis of water-dispersible silver nanoparticles by thermal decomposition of water-soluble silver oxalate precursors.

    PubMed

    Togashi, Takanari; Saito, Kota; Matsuda, Yukiko; Sato, Ibuki; Kon, Hiroki; Uruma, Keirei; Ishizaki, Manabu; Kanaizuka, Katsuhiko; Sakamoto, Masatomi; Ohya, Norimasa; Kurihara, Masato

    2014-08-01

    Silver oxalate, one of the coordination polymer crystals, is a promising synthetic precursor for transformation into Ag nanoparticles without any reducing chemicals via thermal decomposition of the oxalate ions. However, its insoluble nature in solvents has been a great disadvantage, especially for systematic control of crystal growth of the Ag nanoparticles, while such control of inorganic nanoparticles has been generally performed using soluble precursors in homogeneous solutions. In this paper, we document our discovery of water-soluble species from the reaction between the insoluble silver oxalate and N,N-dimethyl-1,3-diaminopropane. The water-soluble species underwent low-temperature thermal decomposition of the oxalate ions at 30 °C with evolution of CO2 to reduce Ag+ to Ag0. Water-dispersible Ag nanoparticles have been successfully synthesized from the water-soluble species in the presence of gelatin via similar thermal decomposition at 100 °C. The gelatin-protected and water-dispersible Ag nanoparticles with a mean diameter of 25.1 nm appeared. In addition, antibacterial activity of the prepared water-dispersible Ag nanoparticles has been preliminarily investigated. PMID:25936049

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

    Microsoft Academic Search

    J. W. NYHAN

    1976-01-01

    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

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

    Microsoft Academic Search

    Jerzy A. Mielczarski; Gonzalo Montes Atenas; Ela Mielczarski

    2005-01-01

    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

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

    NASA Astrophysics Data System (ADS)

    Han, Zhen; Cui, Baoshan; Zhang, Yongtao

    2015-02-01

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

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

    Microsoft Academic Search

    R Romero-Aranda; T Soria; J Cuartero

    2001-01-01

    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.

  10. Water/Wastewater Treatment Plant Operator Qualifications.

    ERIC Educational Resources Information Center

    Water and Sewage Works, 1979

    1979-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Pausch, Johanna; Zhu, Biao; Cheng, Weixin

    2015-04-01

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

  12. PERFORMANCE CHARACTERISTICS OF PACKAGE WATER TREATMENT PLANTS

    EPA Science Inventory

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

  13. Method of generating hydrogen by catalytic decomposition of water

    DOEpatents

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

    2002-01-01

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

  14. Kinetics of cellobiose decomposition under subcritical and supercritical water in continuous flow system

    Microsoft Academic Search

    Jung Hoon Park; Sang Do Park

    2002-01-01

    The effects of reaction temperature, pressure and residence time were investigated with a flow apparatus. Cellobiose decomposition\\u000a kinetics and products in suband supercritical water were examined at temperatures from 320 to 420 °C at pressures from 25\\u000a to 40 MPa, and at residence times within 3 sec. Cellobiose was found to decompose via hydrolysis and pyrolysis. The yield\\u000a of desired

  15. A method to determine plant water source using transpired water

    NASA Astrophysics Data System (ADS)

    Menchaca, L. B.; Smith, B. M.; Connolly, J.; Conrad, M.; Emmett, B.

    2007-04-01

    A method to determine the stable isotope ratio of a plant's water source using the plant's transpired water is proposed as an alternative to standard xylem extraction methods. The method consists of periodically sampling transpired waters from shoots or leaves enclosed in sealed, transparent bags which create a saturated environment, preclude further evaporation and allow the progressive mixing of evaporated transpired water and un-evaporated xylem water. The method was applied on trees and shrubs coexisting in a non-irrigated area where stable isotope ratios of local environmental waters are well characterized. The results show Eucalyptus globulus (tree) and Genista monspessulana (shrub) using water sources of different isotopic ratios congruent with groundwater and soil water respectively. In addition, tritium concentrations indicate that pine trees (Pinus sylvestris) switch water source from soil water in the winter to groundwater in the summer. The method proposed is particularly useful in remote or protected areas and in large scale studies related to water management, environmental compliance and surveillance, because it eliminates the need for destructive sampling and greatly reduces costs associated with laboratory extraction of xylem waters from plant tissues for isotopic analyses.

  16. Water Conservation with Urban Landscape Plants 

    E-print Network

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

    1983-01-01

    levels and two replications of each plant type. There was no difference in water use by St. Augustine grass and buffalo grass during the year of establishment. Daily water use ranged from 0.49 to 0.08 cm per day but was generally 50% class A pan...

  17. Water vapor recovery from plant growth chambers

    NASA Technical Reports Server (NTRS)

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

    1991-01-01

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

  18. 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

  19. 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

  20. 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

  1. 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

  2. 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

  3. 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

  4. 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

  5. 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

  6. 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

  7. 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

  8. Water treatment plants assessment at Talkha power plant.

    PubMed

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

    2002-01-01

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

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

    E-print Network

    Wolfgang Kundt; Eva Gruber

    2006-03-17

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

  10. Adaptive phenotypic plasticity and plant water use

    Microsoft Academic Search

    Adrienne B. NicotraA; Amy DavidsonA

    2010-01-01

    The emergence of new techniques in plant science, including molecular and phenomic tools, presents a novel opportunitytore-evaluatethewayweexaminethephenotype.Ourincreasingcapacityforphenotypingmeansthatnotonly canweconsiderincreasingnumbersofspeciesorvarieties,butalsothatwecaneffectivelyquantifythephenotypesofthese differentgenotypesunderarangeofenvironmentalconditions.Thephenotypicplasticityofagivengenotype,ortherangeof phenotypes, that can be expressed dependent upon environment becomes something we can feasibly assess. Of particular importance is phenotypic variation that increases fitness or survival - adaptive phenotypic plasticity. Here, we examine the case of adaptive phenotypic plasticity in plant water

  11. Water relations of riparian plants from warm desert regions

    Microsoft Academic Search

    Stanley D. Smith; Dale A. Devitt; Anna Sala; James R. Cleverly; David E. Busch

    1998-01-01

    Riparian plants have been classified as “drought avoiders” due to their access to an abundant subsurface water supply. Recent\\u000a water-relations research that tracks water sources of riparian plants using the stable isotopes of water suggests that many\\u000a plants of the riparian zone use ground water rather than stream water, and not all riparian plants are obligate phreatophytes\\u000a (dependent on ground

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

    PubMed

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

    2011-01-01

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

  13. regulating plant water status by stomatal control

    Microsoft Academic Search

    Laury Chaerle; DOMINIQUE VAN DER STRAETEN

    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

  14. NRES 725 PLANT PHYSIOLOGICAL ECOLOGY Reading List Water Balance of Plants

    E-print Network

    Nowak, Robert S.

    1 NRES 725 ­ PLANT PHYSIOLOGICAL ECOLOGY Fall 2008 Reading List ­ Water Balance of Plants I) Water Balance of Plants A) Water potential B) Soil, plant, air continuum C) Physiological control 1) Roots and water uptake 2) Hydraulic conductivity 3) Stomatal conductance and transpiration Recommended Kirkham (05

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

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

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

  16. Enhancement of gas–liquid mass transfer during the unsteady-state catalytic decomposition of ozone in water

    Microsoft Academic Search

    R. Rosal; A. Rodríguez; M. Zerhouni

    2006-01-01

    Unsteady mass transfer and kinetic experiments were conducted in a gas–liquid reactor to study the catalytic and non-catalytic decomposition of ozone in water. In the absence of catalyst, first-order decomposition constants and volumetric mass transfer coefficients were determined at temperatures between 20°C and 30°C. Catalytic runs were performed on fumed colloidal TiO2, which primary particles had an average diameter of

  17. Effects of Water Pollution on Plants

    NSDL National Science Digital Library

    This is an inquiry activity that, while based on a local area (the San Francisco Bay), could be adapted to the teacher's/student's local area. Students perform an experiment in which they observe how water pollution is absorbed into plants. The site contains a teacher's guide and printable student worksheet.

  18. 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...

  19. Monitoring cycle water chemistry in fossil plants

    Microsoft Academic Search

    A. F. Aschoff; D. M. Sopocy; D. T. Eglar; O. Jonas; J. K. Rice; C. C. Stauffer; W. E. Allmon

    1991-01-01

    EPRI report CS-4629, published in 1986, contains operating cycle chemistry guidelines to assist utilities in reducing water and steam contamination and resulting corrosion, scaling, and deposition. These guidelines were based on consensus opinion utilizing information then available and were not validated through actual plant testing. The objectives of this project are: to monitor the major parameters of cycle chemistry in

  20. Microbiological quality of drinking water at eight water treatment plants.

    PubMed

    El-Taweel, G E; Shaban, A M

    2001-11-01

    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

  1. Effects of acid on plant litter decomposition in an arctic lake. [Carex aquatilis

    SciTech Connect

    McKinley, V.L.; Vestal, J.R.

    1982-05-01

    The effects of acid on the microbial decomposition of the dominant aquatic macrophyte (Carex sp.) in Toolik Lake, Alaska were studied in microcosms during the ice-free season of 1980. Toolik Lake is slightly buffered, deep, and very oligotrophic. Microbial activities, as determined by /sup 14/C-acetate incorporation into extractable lipids, associated with Carex litter were signficantly (P < 0.01) reduced within 2 days at pHs of 3.0 and 4.0, but not 5.0, 5.5 or 6.0, as compared with ambient controls (pH 7.4). ATP levels were signficantly reduced at pH 3.0 but not at the other pHs tested. After 18 days, microbial activity signficantly correlated with weight loss (P < 0.05), nitrogen content (P < 0.01), and C/N ratios (P < 0.01) of the liter, but did not correlate with ATP levels. Scanning electron microscopy of the litter surface revealed that the fungi present at ambient pH did not become domimant at pHs below 5.5, diatoms were absent below pH 4.0, and bacterial numbers and extracellular slime were greatly reduced at pH 4.0 and below. Mineralization of Carex /sup 14/C-lignin-labeled or /sup 14/C-cellulose-labeled ligno-cellulose was reduced at pH 2.0, but not at pH 4.0, 5.0, or 6.0, compared with controls (pH '). We concluded that if the pH of the water from this slightly buffered lake was sufficiently reduced, rates of litter decomposition would be significantly reduced.

  2. Effects of Acid on Plant Litter Decomposition in an Arctic Lake

    PubMed Central

    McKinley, Vicky L.; Vestal, J. Robie

    1982-01-01

    The effects of acid on the microbial decomposition of the dominant aquatic macrophyte (Carex sp.) in Toolik Lake, Alaska were studied in microcosms during the ice-free season of 1980. Toolik Lake is slightly buffered, deep, and very oligotrophic. Microbial activities, as determined by 14C-acetate incorporation into extractable lipids, associated with Carex litter were significantly (P < 0.01) reduced within 2 days at pHs of 3.0 and 4.0, but not 5.0, 5.5, or 6.0, as compared with ambient controls (pH 7.4). ATP levels were significantly reduced at pH 3.0, but not at the other pHs tested. After 18 days, microbial activity significantly correlated with weight loss (P < 0.05), nitrogen content (P < 0.01), and C/N ratios (P < 0.01) of the litter, but did not correlate with ATP levels. Scanning electron microscopy of the litter surface revealed that the fungi present at ambient pH did not become dominant at pHs below 5.5, diatoms were absent below pH 4.0, and bacterial numbers and extracellular slime were greatly reduced at pH 4.0 and below. Mineralization of Carex14C-lignin-labeled or 14C-cellulose-labeled lignocellulose was reduced at pH 2.0, but not at pH 4.0, 5.0, or 6.0, compared with controls (pH 7). We concluded that if the pH of the water from this slightly buffered lake was sufficiently reduced, rates of litter decomposition would be significantly reduced. Images PMID:16346015

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

    PubMed Central

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

    2013-01-01

    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. PMID:21402510

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

    PubMed

    Romero-Aranda, R; Soria, T; Cuartero, J

    2001-01-01

    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 (Psi(w)) and osmotic (Psi(Pi)) potentials, gas exchange parameters, stomatal density, leaf chlorophyll and Na content were investigated in the tomato (Lycopersicon esculentum) cultivars, Daniela and Moneymaker. Plants were grown in greenhouse, in sand culture, and irrigated with a complete nutrient solution supplied with 0 (control), 35 and 70 mM NaCl over a period of 2 months. Salinity reduced plant dry weight, height and number of leaves even at 35 mM NaCl. Leaf Psi(w) and Psi(Pi) decreased with salinity but leaf turgor pressures were significantly higher in salinised than in control plants which suggests that bulk tissue turgor did not limit growth under the saline conditions tested. Increasing salinity in the irrigation solution led to both morphological changes [(reduction of plant leaf area and stomatal density) and physiological changes [reduction of stomatal conductance, transpiration, and net CO(2) assimilation (A(CO(2)))] Plant water uptake, measured as the difference between volume of nutrient solution supplied and drainage collected, was closely related to transpiration, stomatal conductance, and stomatal density. Chlorophyll content per unit of leaf area increased with salinity. Reduction of net A(CO(2)) with salinity was explained in higher degree by stomatal conductance and stomatal density than by Na accumulation in the leaves. Although plant water uptake was similar for the two cultivars, Daniela transported, per unit of water uptake, more Na to the leaves than did Moneymaker. However, Daniela reduced leaf area less than did Moneymaker. Water use efficiency, calculated either as the ratio between total plant dry matter and total plant water uptake, or as the ratio between net A(CO(2)) and transpiration, did not change under our saline growth conditions. The contribution of the observed salt-responses to reduction in shoot water loss, plant water uptake and salt loading, while keeping water use efficiency, is discussed in relation to salt tolerance. Because some of these salt-responses take a long time to develop, growing seedlings in seedbeds with saline media could be of interest to better tolerate further salty conditions in the field or greenhouse. PMID:11164598

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

    Microsoft Academic Search

    Yonghong Xie; Dan Yu; Bo Ren

    2004-01-01

    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

  6. Investigation on optimization of conventional drinking water treatment plant

    Microsoft Academic Search

    I. Piri; I. Homayoonnezhad; P. Amirian

    2010-01-01

    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

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

    Microsoft Academic Search

    Ming Yue; Yuan Li; Xunling Wang

    1998-01-01

    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

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

    SciTech Connect

    Brodie, Eoin [Berkeley Lab

    2013-03-01

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

  9. A decomposition approach for the scheduling of a steel plant production

    Microsoft Academic Search

    Iiro Harjunkoski; Ignacio E. Grossmann

    2001-01-01

    In this paper we present a decomposition strategy for solving large scheduling problems using mathematical programming methods. Instead of formulating one huge and unsolvable MILP problem, we propose a decomposition scheme that generates smaller programs that can often be solved to global optimality. The original problem is split into subproblems in a natural way using the special features of steel

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

    Microsoft Academic Search

    Todd E. Dawson

    1993-01-01

    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

  11. The design of water-using systems in petroleum refining using a water-pinch decomposition

    Microsoft Academic Search

    Alberto Alva-Argáez; Antonis C. Kokossis; Robin Smith

    2007-01-01

    Water reuse and recycling offer substantial potential for savings in petroleum refining, as the water volumes processed are large. Presently, there is a lack of methods to systematically screen and analyze design alternatives using a total systems approach. Such an approach would consider effluent treatment, recycle of treated water and freshwater distribution simultaneously. The paper contributes with a systematic methodology

  12. The effect of salinity on plant available water

    Microsoft Academic Search

    Anna Sheldon; Neal W. Menzies; H. Bing So; Ram Dalal

    Salinity acts to inhibit plant access to soil water by increasing the osmotic strength of the soil solution. As the soil dries, the soil solution becomes increasingly concentrated, further limiting plant access to soil water. An experiment was conducted to examine the effect of salt on plant available water in a heavy clay soil, using a relatively salt tolerant species,

  13. A nuclear magnetic resonance study of plant-water relationships

    Microsoft Academic Search

    J. E. A. Reinders

    1987-01-01

    Water is one of the most important constituents of a plant. It is the medium in which many biological reactions take place and nutrients are transported throughout the plant in aqueous solutions. Because it serves as a hydrogen donor In photosynthesis water can be considered as one of the building blocks of the plant structure. Water plays an essential role

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

    Microsoft Academic Search

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

    1996-01-01

    Recently, carbonaceous materials including activated carbon were proven to be effective catalysts for hazardous waste gasification in supercritical water. Using coconut shell activated carbon catalyst, complete decomposition of industrial organic wastes including methanol and acetic acid was achieved. During this process, the total mass of the activated carbon catalyst changes by two competing processes: a decrease in weight via gasification

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

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

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

  16. Effect of Gas Pressure on Decomposition of Indigo Carmine in Water Subjected to Reciprocal Traveling Wave Voltage Pulse

    Microsoft Academic Search

    K. Kadowaki; T. Sone; H. Nishiyama; I. Kitani

    2006-01-01

    This paper describes experimental results of decomposition of an organic material in water using repetitive surface discharges produced by reciprocal traveling wave voltage pulse. A point electrode with a CR high-pass-filter at one end of a long coaxial cable was faced on a surface of 3 mm thick water layer on the grounded-plate in a low-pressure chamber. When the cable

  17. Decomposition of duckweed (Lemna gibba) under axenic and microbial [-2pt] conditions: flux of nutrients between litter water and sediment, the impact of leaching and microbial degradation

    Microsoft Academic Search

    Sándor Szabó; Mihály Braun; Péter Nagy; Sándor Balázsy; Otto Reisinger

    2000-01-01

    The decomposition of axenic Lemna gibba has been studied over a 200 day period under laboratory conditions in the presence and absence of wastewater micro-organisms. The residual mass of plant litter in the decomposition vessels decreased three times more rapidly under biotic than abiotic conditions. The organic matter in the duckweed litter lost about half its weight within 67.9 days

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

    SciTech Connect

    Kozawa, Takahiro; Onda, Ayumu [Research Laboratory of Hydrothermal Chemistry, Faculty of Science, Kochi University, 2-5-1 Akebono-cho, Kochi 780-8520 (Japan); Yanagisawa, Kazumichi, E-mail: yanagi@kochi-u.ac.j [Research Laboratory of Hydrothermal Chemistry, Faculty of Science, Kochi University, 2-5-1 Akebono-cho, Kochi 780-8520 (Japan); Kishi, Akira; Masuda, Yasuaki [Rigaku Corporation, 3-9-12 Matsubara-cho, Akishima-shi, Tokyo 196-8666 (Japan)

    2011-03-15

    Thermal decomposition process of zinc hydroxide chloride (ZHC), Zn{sub 5}(OH){sub 8}Cl{sub 2}.H{sub 2}O, 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 {beta}-Zn(OH)Cl as the intermediate phase, leaving amorphous hydrated ZnCl{sub 2}. In humid N{sub 2} with P{sub H{sub 2O}}=4.5 and 10 kPa, the hydrolysis of residual ZnCl{sub 2} was accelerated and the theoretical amount of ZnO was obtained at lower temperatures than in dry N{sub 2}, whereas significant weight loss was caused by vaporization of residual ZnCl{sub 2} in dry N{sub 2}. 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 abstract: Thermal decomposition process of zinc hydroxide chloride (ZHC), Zn{sub 5}(OH){sub 8}Cl{sub 2}.H{sub 2}O, 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. Display Omitted highlights: > We examine the thermal decomposition of zinc hydroxide chloride in water vapor. > Water vapor had no effects on its thermal decomposition up to 230 {sup o}C. > Water vapor accelerated the decomposition of the residual ZnCl{sub 2} in ZnO. > Without water vapor, a large amount of ZnCl{sub 2} evaporated to form the c-axis oriented ZnO.

  19. 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

  20. 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

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

    NASA Astrophysics Data System (ADS)

    Biswas, Rajib; Furtado, Jonathan; Bagchi, Biman

    2013-10-01

    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.

  2. Metabolic responses of mesophytes to plant water deficits

    Microsoft Academic Search

    A. D. Hanson; W. D. Hitz

    1982-01-01

    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.

  3. 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

    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

    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

  4. 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...

  5. Spatial Patterns in Water Quality Associated with Submersed Plant Beds

    Microsoft Academic Search

    Renee K. Gruber; Deborah C. Hinkle; W. Michael Kemp

    2011-01-01

    This study describes the influence of submersed plant beds on spatial distributions of key water quality variables. An on-board\\u000a flow-through water sampling system was used to investigate patterns in turbidity, chlorophyll-a, temperature, dissolved oxygen, and pH across a robust stand of the submersed plant Stuckenia pectinata. Spatially interpolated maps show that water quality conditions were significantly altered within this plant

  6. Plant species and nutritional-mediated control over rhizodeposition and root decomposition

    Microsoft Academic Search

    Tanja A. J. Van der Krift; Peter J. Kuikman; Frans Möller; Frank Berendse

    2001-01-01

    This study focuses on the influence of nitrogen (N) availability and species on rhizodeposition and on decomposition of rhizodeposits, roots and soil organic matter. Four perennial grass species were studied that are characteristic of grassland habitats that differ in nutrient availability. These perennial grass species, Holcus lanatus L., Festuca rubra L., Anthoxanthum odoratum L. and Festuca ovina L., were homogeneously

  7. Aquaporins: highly regulated channels controlling plant water relations.

    PubMed

    Chaumont, François; Tyerman, Stephen D

    2014-04-01

    Plant growth and development are dependent on tight regulation of water movement. Water diffusion across cell membranes is facilitated by aquaporins that provide plants with the means to rapidly and reversibly modify water permeability. This is done by changing aquaporin density and activity in the membrane, including posttranslational modifications and protein interaction that act on their trafficking and gating. At the whole organ level aquaporins modify water conductance and gradients at key "gatekeeper" cell layers that impact on whole plant water flow and plant water potential. In this way they may act in concert with stomatal regulation to determine the degree of isohydry/anisohydry. Molecular, physiological, and biophysical approaches have demonstrated that variations in root and leaf hydraulic conductivity can be accounted for by aquaporins but this must be integrated with anatomical considerations. This Update integrates these data and emphasizes the central role played by aquaporins in regulating plant water relations. PMID:24449709

  8. Moisture drives surface decomposition in thawing tundra

    NASA Astrophysics Data System (ADS)

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

    2013-07-01

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

  9. Survival strategies of plants during water stress

    SciTech Connect

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

    1989-04-01

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

  10. Thin-film semiconducting TiO2 combined with ferroelectrics for photoassisted water decomposition

    SciTech Connect

    Inoue, Y.; Okamura, M.; Sato, K.

    1985-11-21

    A thin-film semiconducting TiO2 was deposited by a reactive-evaporation method on ferroelectric substrates possessing a polarization vector and was examined, after Pt deposition, for water decomposition in the liquid and gas phases by illumination with an Xe lamp. The TiO2 films were in the thickness range 20-200 nm and were obtained in slightly oxygen-deficient states. The ferroelectrics employed were poled single crystals of LiTaO3 with the polarization vector perpendicular to the surface (exposing either a positive or negative polar surface) and a poled single crystal of LiNbO3 with the polarization vector parallel to the surface. For comparison, an -Al2O3 single crystal was also used. The photocatalytic activity differed depending on the substrate. From the TiO2-thickness dependence upon H2 evolution, it is shown that the ferroelectric polarization field, in particular the perpendicular polarization, works to enhance remarkably the photocatalytic activity of the combined semiconducting TiO2 films. The polarization effect is discussed. 20 references, 5 figures, 1 table.

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

    ERIC Educational Resources Information Center

    Etherington, John R.

    1988-01-01

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

  12. Reuse of waste water from ready-mixed concrete plants

    Microsoft Academic Search

    Stamatis Tsimas; Monika Zervaki

    2011-01-01

    Purpose – The purpose of this study is the examination of the properties of waste water obtained from a ready-mixed concrete plant and its utilization potential as mixing water for concrete production. Design\\/methodology\\/approach – Samples of waste water from several points of a water recycling process from a ready-mixed concrete plant were examined for their chemical properties (Cl-, SO42-, alkalies,

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

    PubMed

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

    2015-08-01

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

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

    Microsoft Academic Search

    Yu-ichi Suzuki; Hideyuki Tagaya; Junichi Kadokawa; Koji Chiba; Tetsuo Asou

    1999-01-01

    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

  15. Effects of acid on plant litter decomposition in an arctic lake. [Carex aquatilis

    Microsoft Academic Search

    V. L. McKinley; J. R. Vestal

    1982-01-01

    The effects of acid on the microbial decomposition of the dominant aquatic macrophyte (Carex sp.) in Toolik Lake, Alaska were studied in microcosms during the ice-free season of 1980. Toolik Lake is slightly buffered, deep, and very oligotrophic. Microbial activities, as determined by ¹⁴C-acetate incorporation into extractable lipids, associated with Carex litter were signficantly (P < 0.01) reduced within 2

  16. A micropump based on water potential difference in plants

    Microsoft Academic Search

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

    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

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

    NASA Astrophysics Data System (ADS)

    Katayanagi, Hitoshi; Miki, Norihisa

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

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

    NASA Technical Reports Server (NTRS)

    Walker, R. D., Jr.

    1973-01-01

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

  19. Simulation of Water Transport in the Soil-Plant - System.

    NASA Astrophysics Data System (ADS)

    Guo, Yimei

    1992-01-01

    The objective of this dissertation is to develop a mechanistic model of water transport in the soil-plant -atmosphere system that describes the plant's physical expression of water stress to study the effects of environmental factors, and plant hydraulic and physical properties on plant water transport. The model includes soil moisture uptake, soil heat and water transfer, evapotranspiration, and energy partitioning in the canopy and at the soil surface. The model inputs are: daily weather data (air temperature, dew point temperature, wind speed, and solar radiation); initial soil moisture and temperature profiles; plant characteristics; root density; and soil hydraulic properties. The model user may select from a number of outputs. Principal outputs include: leaf resistance, leaf temperature, soil moisture profile and evapotranspiration rate. The model describes a feedback mechanism by which transpiration controls leaf water potential, leaf water potential influences leaf resistance, and leaf resistance which, in turn, controls transpiration. The simulation runs represented the energy partitioning in the canopy and at the soil surface, and the diurnal variation of temperatures and vapor pressures of the leaf, the canopy air, and the soil surface. The relationships of leaf water potential to soil water potential, leaf resistance and transpiration were also presented. In addition, results show that root water extraction is related to the root length density profile and the soil moisture profile. The model mechanistically describes the water transport in the soil-plant-atmosphere system. The results of model validation indicated that the model is capable of simulating plant water transport under natural conditions with reasonable accuracy. Results show that the model simulates the basic features of the system including feedback processes. The sensitivity studies show that the model may be used to study plant water response to environmental factors and plant properties. The model is also useful for estimating evapotranspiration and the soil moisture profile and may provide information for irrigation and soil water management. (Abstract shortened with permission of author.).

  20. AQUATIC PLANTS FOR BIOREMEDIATION OF WASTE WATER

    Microsoft Academic Search

    Assia A. El Falaky; S. A. Aboulroos; A. A. Saoud; M. A. Ali

    The ability of aquatic plants to accumulate heavy metals was examined in Bahr in El Bakar drain as one of the first sized drains in Egypt heavily polluted with heavy metals. Metal enrichment was found to be dependent on the plant species and metal type. The most efficient plant species in accumulating heavy metals were Eichhornia crassipes (floating plant), Ceratophyllum

  1. STEAM GENERATOR WATER LEVEL CONTROL OF A NUCLEAR POWER PLANT

    Microsoft Academic Search

    PETRU MAIOR

    Poor control of the steam generator water level in the secondary circuit of a nuclear power plant can lead to frequent reactor shutdowns. These shutdowns are caused by violation of safety limits on the water level and are common at low operating power where the plant exhibits strong non-minimum phase characteristics and flow measurements are unreliable. This work presents a

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

    ERIC Educational Resources Information Center

    Mansfield, Donald H.; Anderson, Jay E.

    1980-01-01

    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)

  3. Air-cooled condensers eliminate plant water use

    SciTech Connect

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

    2008-09-15

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

  4. Costs and water quality effects of wastewater treatment plant centralization

    SciTech Connect

    Macal, C.M.; Broomfield, B.J.

    1980-01-01

    The costs and water quality impacts of two regional configurations of municipal wastewater treatment plants in Northeastern Illinois are compared. In one configuration, several small treatment plants are consolidated into a smaller number of regional facilities. In the other, the smaller plants continue to operate. Costs for modifying the plants to obtain various levels of pollutant removal are estimated using a simulation model that considers the type of equipment existing at the plants and the costs of modifying that equipment to obtain a range of effluent levels for various pollutants. A dynamic water-quality/hydrology simulation model is used to determine the water quality effects of the various treatment technologies and pollutant levels. Cost and water quality data are combined and the cost-effectiveness of the two treatment configurations is compared. The regionalized treatment-plant configuration is found to be the more cost-effective.

  5. INTEGRATED STEEL PLANT POLLUTION STUDY FOR TOTAL RECYCLE OF WATER

    EPA Science Inventory

    The report gives results of an engineering study of five integrated U.S. steel plants to determine how each might ultimately achieve total recycle of water. The plants represent a broad cross section of plant-specific factors (e.g., size, age, location, and available space) that ...

  6. Development of a Heavy Water Detritiation Plant for PIK Reactor

    SciTech Connect

    Alekseev, I.A.; Bondarenko, S.D.; Fedorchenko, O.A.; Konoplev, K.A.; Vasyanina, T.V.; Arkhipov, E.A.; Uborsky, V.V

    2005-07-15

    The research reactor PIK should be supplied with a Detritiation Plant (DP) to remove tritium from heavy water in order to reduce operator radiation dose and tritium emissions. The original design of the reactor PIK Detritiation Plant was completed several years ago. A number of investigations have been made to obtain data for the DP design. Nowadays the design of the DP is being revised on a basis of our investigations. The Combined Electrolysis and Catalytic Exchange (CECE) process will be used at the Detritiation Plant instead of Vapor Phase Catalytic Exchange. The experimental industrial plant for hydrogen isotope separation on the basis of the CECE process is under operation in Petersburg Nuclear Physics Institute. The plant was updated to provide a means for heavy water detritiation. Very high detritiation factors have been achieved in the plant. The use of the CECE process will allow the development of a more compact and less expensive detritiation plant for heavy water reactor PIK.

  7. Plant experience with temporary reverse osmosis makeup water systems

    SciTech Connect

    Polidoroff, C.

    1986-01-01

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

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

    PubMed Central

    Bains, William; Xiao, Yao; Yu, Changyong

    2015-01-01

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

  9. Boiling water reactor plant analyzer development at Brookhaven National Laboratory

    Microsoft Academic Search

    H. S. Cheng; W. Wulff; A. N. Mallen; S. V. LeKach; A. Stritar; R. J. Cerbone

    1986-01-01

    Advanced technology for high-speed interactive nuclear power plant simulations is of great value for timely resolution of safety issues, for plant monitoring, and for computer-aided emergency responses to an accident. Presented is the methodology employed at Brookhaven National Laboratory to develop a boiling water reactor (BWR) plant analyzer capable of simulating severe plant transients at much faster than real-time process

  10. Water Conservation with Urban Landscape Plants

    E-print Network

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

    Water shortages are a common problem in much of the southwest. Increasing urbanization and increasing population places greater demands on dwindling water supplies. Over half of the water used in urban areas of the southwest is used...

  11. MODELLING OF COAGULANT DOSAGE IN A WATER TREATMENT PLANT

    Microsoft Academic Search

    N. Valentin; T. Denoeux; F. Fotoohi

    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

  12. Plant-water relations and adaptation to stress

    Microsoft Academic Search

    Neil C. Turner; John E. Begg

    1981-01-01

    Many of the effects of water deficits on the growth and yield of plants are clearly evident throughout arid and semi-arid regions of the world. The dramatic increases in yields of cereals during the past 40 years in regions where a regular supply of water is assured through rainfall or irrigation, and the smaller increases where water supply is limited,

  13. 77 FR 73056 - Initial Test Programs for Water-Cooled Nuclear Power Plants

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-07

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

  14. 78 FR 35330 - Initial Test Programs for Water-Cooled Nuclear Power Plants

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-12

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

  15. Economic Comparison of Waste Water Cleaning for Central Waste Water Treatment Plant and Decentralised System with Smaller Waste Water Treatment Plants

    Microsoft Academic Search

    J. ZORKO; D. GORICANEC

    In presented paper two economic analysis of investments for integrated waste water collection and treatment in selected area are presented. The methods of Net present value (NPV) and Capitalised costs (CC) have been used to compare economic efficiency of construction central waste water treatment plant with collecting system and construction of decentralised waste water treatment plants with belonging collecting system

  16. Water use, productivity and interactions among desert plants

    SciTech Connect

    Ehleringer, J.R.

    1992-11-17

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

  17. Green Roof Water Harvesting and Recycling Effects on Soil and Water Chemistry and Plant Physiology 

    E-print Network

    Laminack, Kirk Dickison

    2014-04-17

    on each green roof. Plant water potential, specific leaf area and rates of photosynthesis, transpiration, and conductivity were not significantly different between roofs which helped to further conclude that water quality parameters remained within...

  18. FEATURES OF WASTE WATER QUALITY IN ZONGGUAN WATER PLANT

    Microsoft Academic Search

    Hadi Naba Shakir

    This paper takes waste water from Zongguan waterworks as a research object. The waste water was monitored consecutively and found that: the SS of waste water was more than 90 times of which in original water, COD was more than 30 times, and Fe was 58 times. The SS and turbidness showed no linear relation except when they were lower.

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

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

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

    SciTech Connect

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

    2011-01-01

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

  1. Atlantic White Cedar swamp: Effects of temperature and water table position on decomposition

    E-print Network

    Vallino, Joseph J.

    warming potential for various scenarios. The largest global warming potential was calculated for the wet and warm scenario. This data has large implications for global warming and decomposition of the peat within warming potential, global warming Introduction: Atlantic White Cedar swamps are a rare species that often

  2. 77 FR 3009 - Knowledge and Abilities Catalog for Nuclear Power Plant Operators: Advanced Boiling Water Reactors

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-20

    ...Abilities Catalog for Nuclear Power Plant Operators: Advanced Boiling Water Reactors AGENCY: Nuclear Regulatory Commission...Abilities Catalog for Nuclear Power Plant Operators: Advanced Boiling Water Reactors.'' DATES:...

  3. 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

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

    PubMed Central

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

    2014-01-01

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

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

    E-print Network

    Kumana, J. D.

    2000-01-01

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

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

    EPA Science Inventory

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

  7. WATER-INK LANDSCAPE PAINTINGS WITH PLANT COMMUNITIES

    Microsoft Academic Search

    Philip C. Hsu; Sue-Kai Yang

    2007-01-01

    A Chinese water-ink landscape painting doesn't interest in the realistic rendering. Nevertheless, it much more focuses on artistic inner-mind and esthetic expression using hairy brush stroke and ink dispersion. This paper developed a tree planting system. We transformed a real world's terrain geometrical model into a water-ink styled painting, and rendered the plant communities in the terrain as well. This

  8. Nuclear plant service water system aging degradation assessment: Phase 1

    Microsoft Academic Search

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

    1989-01-01

    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

  9. Irrigation of pepper plant ( Capsicum sp.) with water containing acrolein

    Microsoft Academic Search

    Hugo A. Caldironi; Diego J. Bentivegna; Miles R. Rhea

    2004-01-01

    MAGNACIDE® H herbicide (a.i. acrolein (2-propenal)) is an aquatic herbicide applied through underwater injection into agricultural irrigation canals for the control of submerged aquatic weeds. In support of the products national registration in Argentina, additional information was required pertaining to the potential persistence of acrolein residuals in plants irrigated with water treated with this herbicide. Pepper plants (Capsicum sp.) were

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

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

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

  11. Chemical Control of Water Loss in Growing Plants

    Microsoft Academic Search

    E. M. Stoddard; P. M. Miller

    1962-01-01

    Immersing the roots of growing strawberry plants in aqueous solutions of 8-hydroxyquinoline sulfate closes the stomata, reduces water loss, and increases the time before complete wilting under drought conditions. Under such drought conditions plant survival and vigor are increased. Prolonged closing of the stomata seems to be the principal mode of action of the chemical.

  12. South Florida ornamental plant grower perspectives: water conservation management practices 1

    E-print Network

    Migliaccio, Kati White

    ABE 369 South Florida ornamental plant grower perspectives: water conservation management practices ornamental plant grower perspectives: water conservation management.... 2 water quantity and quality historically experienced periods of extended droughts which threaten production capabilities thus making water

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

    USGS Publications Warehouse

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

    1996-01-01

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

  14. Optical fluorescence biosensor for plant water stress detection

    NASA Astrophysics Data System (ADS)

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

    2007-05-01

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

  15. A new look at water transport regulation in plants.

    PubMed

    Martínez-Vilalta, Jordi; Poyatos, Rafael; Aguadé, David; Retana, Javier; Mencuccini, Maurizio

    2014-10-01

    Plant function requires effective mechanisms to regulate water transport at a variety of scales. Here, we develop a new theoretical framework describing plant responses to drying soil, based on the relationship between midday and predawn leaf water potentials. The intercept of the relationship (?) characterizes the maximum transpiration rate per unit of hydraulic transport capacity, whereas the slope (?) measures the relative sensitivity of the transpiration rate and plant hydraulic conductance to declining water availability. This framework was applied to a newly compiled global database of leaf water potentials to estimate the values of ? and ? for 102 plant species. Our results show that our characterization of drought responses is largely consistent within species, and that the parameters ? and ? show meaningful associations with climate across species. Parameter ? was ?1 in most species, indicating a tight coordination between the gas and liquid phases of water transport, in which canopy transpiration tended to decline faster than hydraulic conductance during drought, thus reducing the pressure drop through the plant. The quantitative framework presented here offers a new way of characterizing water transport regulation in plants that can be used to assess their vulnerability to drought under current and future climatic conditions. PMID:24985503

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

    PubMed

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

    2012-03-01

    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

  17. Manganese cluster in photosynthesis: Where plants oxidize water to dioxygen

    Microsoft Academic Search

    Vittal K. Yachandra; M. P. Klein; K. Sauer

    1996-01-01

    The essential involvement of manganese in photosynthetic water oxidation was implicit in the observation by Pirson in 1937 that plants and algae deprived of Mn in their growth medium lost the ability to evolve Oâ. Addition of this essential element to the growth medium resulted in the restoration of water oxidation within 30 min. There is increased interest in the

  18. Econometric Approach to Water Use Estimation in Power Plants

    Microsoft Academic Search

    Perini Praveena Sri

    2010-01-01

    The purpose of this paper is to examine water use estimation in hydel and thermal electric power plants in selected regions i.e. Coastal, Rayalaseema and Telangana regions of Andhra Pradesh. The study primarily focuses on the realistic fundamental premise thatthermal electric and hydro electric energy generation is responsible for the largest monthly volume of water withdrawals in four seasons (i.e.

  19. Econometric Approach to Water Use Estimation in Power Plants

    Microsoft Academic Search

    Perini Praveena Sri

    2010-01-01

    The purpose of this paper is to examine water use estimation in hydel and thermal electric power plants in selected regions i.e. Coastal, Rayalaseema and Telangana regions of Andhra Pradesh. The study primarily focuses on the realistic fundamental premise that thermal electric and hydro electric energy generation is responsible for the largest monthly volume of water withdrawals in four seasons

  20. INORGANIC CHEMICAL CHARACTERIZATION OF WATER TREATMENT PLANT RESIDUALS

    EPA Science Inventory

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

  1. Effects of water quality on silica fouling of desalination plants

    Microsoft Academic Search

    R. Sheikholeslami; S. Tan

    1999-01-01

    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,

  2. ENGINEERING EVALUATION STUDIES HEAVY WATER MODERATED POWER REACTOR PLANTS

    Microsoft Academic Search

    W. A. Chittenden; G. F. Hoveke

    1961-01-01

    Engineering evaluation studies focused on heavy water moderated power ; reactor technology are discussed. Stainless steel, carbon steel, and Zircaloy-2 ; corrosion data are presented. Water treatment and corrosion product deposition ; are described. A study aimed at evaluating the effect of incorporating alternate ; low cost materials into a full-scale boiling DâO direct cycle power reactor ; plant was

  3. REGULAR ARTICLE Small-scale variability in water storage and plant available

    E-print Network

    Schwinning, Susan - Department of Biology, Texas State University

    REGULAR ARTICLE Small-scale variability in water storage and plant available water in shallow in water storage and plant access to water in the rocky soils of a karst savanna dominated by Ashe juniper used to infer recharge and plant uptake of soil water. Predawn water potentials of trees were sampled

  4. Monitoring cycle water chemistry in fossil plants

    Microsoft Academic Search

    1992-01-01

    This report presents a survey of foreign water treatment practices and experience in 12 countries together with the results of cycle water and steam chemistry monitoring from 29 units in nine countries andnine different organizations. With data from the open literature, over 40 drum and 30 once-through boiler units are included. The report covers drum boilers using phosphate, phosphate plus

  5. The evolution of water transport in plants: an integrated approach.

    PubMed

    Pittermann, J

    2010-03-01

    This review examines the evolution of the plant vascular system from its beginnings in the green algae to modern arborescent plants, highlighting the recent advances in developmental, organismal, geochemical and climatological research that have contributed to our understanding of the evolution of xylem. Hydraulic trade-offs in vascular structure-function are discussed in the context of canopy support and drought and freeze-thaw stress resistance. This qualitative and quantitative neontological approach to palaeobotany may be useful for interpreting the water-transport efficiencies and hydraulic limits in fossil plants. Large variations in atmospheric carbon dioxide levels are recorded in leaf stomatal densities, and may have had profound impacts on the water conservation strategies of ancient plants. A hypothesis that links vascular function with stomatal density is presented and examined in the context of the evolution of wood and/or vessels. A discussion of the broader impacts of plant transport on hydrology and climate concludes this review. PMID:20156293

  6. Investigating water transport through the xylem network in vascular plants.

    PubMed

    Kim, Hae Koo; Park, Joonghyuk; Hwang, Ildoo

    2014-04-01

    Our understanding of physical and physiological mechanisms depends on the development of advanced technologies and tools to prove or re-evaluate established theories, and test new hypotheses. Water flow in land plants is a fascinating phenomenon, a vital component of the water cycle, and essential for life on Earth. The cohesion-tension theory (CTT), formulated more than a century ago and based on the physical properties of water, laid the foundation for our understanding of water transport in vascular plants. Numerous experimental tools have since been developed to evaluate various aspects of the CTT, such as the existence of negative hydrostatic pressure. This review focuses on the evolution of the experimental methods used to study water transport in plants, and summarizes the different ways to investigate the diversity of the xylem network structure and sap flow dynamics in various species. As water transport is documented at different scales, from the level of single conduits to entire plants, it is critical that new results be subjected to systematic cross-validation and that findings based on different organs be integrated at the whole-plant level. We also discuss the functional trade-offs between optimizing hydraulic efficiency and maintaining the safety of the entire transport system. Furthermore, we evaluate future directions in sap flow research and highlight the importance of integrating the combined effects of various levels of hydraulic regulation. PMID:24609652

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

    NASA Technical Reports Server (NTRS)

    Bubenheim, D. L.

    1991-01-01

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

  8. Water relations of riparian plants from warm desert regions

    USGS Publications Warehouse

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

    1998-01-01

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

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

    SciTech Connect

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

    2010-08-19

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

  10. DOSE CONTROLLER FOR AGUACLARA WATER TREATMENT PLANTS

    EPA Science Inventory

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

  11. Energy from fresh and brackish water aquatic plants

    SciTech Connect

    Benemann, J.R.

    1981-01-01

    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.

  12. Optimization of a Chilled Water Plant Using a Forward Plant Model 

    E-print Network

    Zhang, Z.; Turner, W. D.; Chen, Q.; Xu, C.; Deng, S.

    2010-01-01

    problem and can be solved with the generalized reduced gradient nonlinear solver. The application of this model is illustrated with a practical chilled water system. INTRODUCTION A chiller plant produces chilled water (ChW) and transports... it to end users, such as air handling units, through piping. Ever since 1990, traditional ChW plant design has begun utilizing a primary- secondary loop configuration. The imbalance in flow between the primary and secondary circuits results in flow...

  13. Cadaver decomposition in terrestrial ecosystems.

    PubMed

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

    2007-01-01

    A dead mammal (i.e. cadaver) is a high quality resource (narrow carbon:nitrogen ratio, high water content) that releases an intense, localised pulse of carbon and nutrients into the soil upon decomposition. Despite the fact that as much as 5,000 kg of cadaver can be introduced to a square kilometre of terrestrial ecosystem each year, cadaver decomposition remains a neglected microsere. Here we review the processes associated with the introduction of cadaver-derived carbon and nutrients into soil from forensic and ecological settings to show that cadaver decomposition can have a greater, albeit localised, effect on belowground ecology than plant and faecal resources. Cadaveric materials are rapidly introduced to belowground floral and faunal communities, which results in the formation of a highly concentrated island of fertility, or cadaver decomposition island (CDI). CDIs are associated with increased soil microbial biomass, microbial activity (C mineralisation) and nematode abundance. Each CDI is an ephemeral natural disturbance that, in addition to releasing energy and nutrients to the wider ecosystem, acts as a hub by receiving these materials in the form of dead insects, exuvia and puparia, faecal matter (from scavengers, grazers and predators) and feathers (from avian scavengers and predators). As such, CDIs contribute to landscape heterogeneity. Furthermore, CDIs are a specialised habitat for a number of flies, beetles and pioneer vegetation, which enhances biodiversity in terrestrial ecosystems. PMID:17091303

  14. WATER TREATMENT PLANT OPTIMIZATION BY CONTROLLING THE SUSPENDED SOLIDS PHYSICOCHEMICAL ENVIRONMENT

    Microsoft Academic Search

    Kamal El-Nahhas

    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,

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

    PubMed

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

    2009-09-01

    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

  16. Non-Additive Effects on Decomposition from Mixing Litter of the Invasive Mikania micrantha H.B.K. with Native Plants

    PubMed Central

    Chen, Bao-Ming; Peng, Shao-Lin; D’Antonio, Carla M.; Li, Dai-Jiang; Ren, Wen-Tao

    2013-01-01

    A common hypothesis to explain the effect of litter mixing is based on the difference in litter N content between mixed species. Although many studies have shown that litter of invasive non-native plants typically has higher N content than that of native plants in the communities they invade, there has been surprisingly little study of mixing effects during plant invasions. We address this question in south China where Mikania micrantha H.B.K., a non-native vine, with high litter N content, has invaded many forested ecosystems. We were specifically interested in whether this invader accelerated decomposition and how the strength of the litter mixing effect changes with the degree of invasion and over time during litter decomposition. Using litterbags, we evaluated the effect of mixing litter of M. micrantha with the litter of 7 native resident plants, at 3 ratios: M1 (1?4,?=?exotic:native litter), M2 (1?1) and M3 (4?1,?=?exotic:native litter) over three incubation periods. We compared mixed litter with unmixed litter of the native species to identify if a non-additive effect of mixing litter existed. We found that there were positive significant non-additive effects of litter mixing on both mass loss and nutrient release. These effects changed with native species identity, mixture ratio and decay times. Overall the greatest accelerations of mixture decay and N release tended to be in the highest degree of invasion (mix ratio M3) and during the middle and final measured stages of decomposition. Contrary to expectations, the initial difference in litter N did not explain species differences in the effect of mixing but overall it appears that invasion by M. micrantha is accelerating the decomposition of native species litter. This effect on a fundamental ecosystem process could contribute to higher rates of nutrient turnover in invaded ecosystems. PMID:23840435

  17. Soluble arsenic removal at water treatment plants

    SciTech Connect

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

    1995-04-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

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

    Microsoft Academic Search

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

    2001-01-01

    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

  20. 1985 fossil plant water chemistry symposium: Proceedings

    Microsoft Academic Search

    1986-01-01

    A three day EPRI Symposium devoted to water chemistry, corrosion, and scale control in fossil utility steam cycles was held June 11-13, 1985 in Atlanta, Georgia. The purpose of the Symposium was to review and discuss US and foreign practices, corrosion control requirements for boilers, turbines, and other cycle components, sampling and instrumentation, and problems with cycling units. After the

  1. Wetlands: Water, Wildlife, Plants, and People.

    ERIC Educational Resources Information Center

    Vandas, Steve

    1992-01-01

    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…

  2. Plant Response to Differential Soil Water Content and Salinity

    NASA Astrophysics Data System (ADS)

    Moradi, A. B.; Dara, A.; Kamai, T.; Ngo, A.; Walker, R.; Hopmans, J. W.

    2011-12-01

    Root-zone soil water content is extremely dynamic, governed by complex and coupled processes such as root uptake, irrigation, evaporation, and leaching. Root uptake of water and nutrients is influenced by these conditions and the processes involved. Plant roots are living and functioning in a dynamic environment that is subjected to extreme changes over relatively short time and small distances. In order to better manage our agricultural resources and cope with increasing constraints of water limitation, environmental concerns and climate change, it is vital to understand plants responses to these changes in their environment. We grew chick pea (Cicer arietinum) plants, in boxes of 30 x 25 x 1 cm dimensions filled with fine sand. Layers of coarse sand (1.5 cm thick) were embedded in the fine-sand media to divide the root growth environment into sections that were hydraulically disconnected from each other. This way, each section could be independently treated with differential levels of water and salinity. The root growth and distribution in the soil was monitored on daily bases using neutron radiography. Daily water uptake was measured by weighing the containers. Changes of soil water content in each section of the containers were calculated from the neutron radiographs. Plants that part of their root system was stressed with drought or salinity showed no change in their daily water uptake rate. The roots in the stressed sections stayed turgid during the stress period and looked healthy in the neutron images. However the uptake rate was severely affected when the soil in the non-stressed section started to dry. The plants were then fully irrigated with water and the water uptake rate recovered to its initial rate shortly after irrigation. The neutron radiographs clearly illustrated the shrinkage and recovery of the roots under stress and the subsequent relief. This cycle was repeated a few times and the same trend could be reproduced. Our results show that plants' response to water- or salinity-stress ranges from full compensation to severe reduction in transpiration, depending on the availability of water in their surrounding soil. Results of applying different treatments of salinity and drought will be shown. Available models of root water uptake will be employed to simulate the obtained results.

  3. To prevent the occurrence of black water agglomerate through delaying decomposition of cyanobacterial bloom biomass by sediment microbial fuel cell.

    PubMed

    Zhou, Yan-Li; Jiang, He-Long; Cai, Hai-Yuan

    2015-04-28

    Settlement of cyanobacterial bloom biomass (CBB) into sediments in eutrophic lakes often induced the occurrence of black water agglomerate and then water quality deterioration. This study investigated the effect of sediment microbial fuel cell (SMFC) on CBB removal in sediments and related water pollution. Sediment bulking and subsequent black water from decomposition of settled CBB happened without SMFC, but were not observed over 100-day experiments with SMFC employment. While CBB in sediments improved power production from SMFC, the removal efficiency of organic matters in CBB-amended sediments with SMFC was significantly lower than that without SMFC. Pyrosequencing analysis showed higher abundances of the fermentative Clostridium and acetoclastic methanogen in CBB-amended bulk sediments without SMFC than with SMFC at the end of experiments. Obviously, SMFC operation changed the microbial community in CBB-amended sediments, and delayed the CBB degradation against sediment bulking. Thus, SMFC could be potentially applied as pollution prevention in CBB-settled and sensitive zones in shallow lakes. PMID:25621829

  4. Water, plants, and early human habitats in eastern Africa

    PubMed Central

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

    2013-01-01

    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. PMID:23267102

  5. Visible light-induced decomposition of a fluorotelomer unsaturated carboxylic acid in water with a combination of tungsten trioxide and persulfate.

    PubMed

    Hori, Hisao; Ishiguro, Atsushi; Nakajima, Kohei; Sano, Taizo; Kutsuna, Shuzo; Koike, Kazuhide

    2013-11-01

    Photochemical decomposition of a fluorotelomer unsaturated carboxylic acid, C3F7CFCHCOOH (1), in the presence of WO3 and an electron acceptor (S2O8(2-) or H2O2) in water under visible-light irradiation was investigated. Under an O2 atmosphere, 1 was not decomposed either by TiO2 (P25) or WO3 alone. A combination of WO3 and H2O2 also resulted in almost no decomposition of 1. In contrast, irradiation in the presence of a combination of WO3 and S2O8(2-) (potassium salt) efficiently decomposed 1 to F(-), CO2, C3F7COOH, and C2F5COOH. The decomposition of 1 was affected by the counter cation of S2O8(2-): the decomposition extent was higher with K2S2O8 than with (NH4)2S2O8. The decomposition of 1 was further enhanced when the reaction in the presence of WO3 and K2S2O8 was carried out under an argon atmosphere. Under O2, the amount of H2O2 formed in the reaction solution was an order of magnitude higher than the amount formed under argon. This fact suggests that the decrease in the decomposition of 1 under O2 can be ascribed to the formation of H2O2, which consumed S2O8(2-) and SO4(-). PMID:24112660

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

    NASA Astrophysics Data System (ADS)

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

    2010-05-01

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

  7. Survival strategies of plants during water stress

    Microsoft Academic Search

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

    1989-01-01

    Fluorescence and gas exchange of bean, maize, sunflower and wooly foxglove were simultaneously measured at 250 μmol quanta\\/m²\\/s. Under severe water stresses conditions about 40% of the photochemical energy was converted to heat at PS II. This is interpreted as a protective mechanism against photoinhibitory damage when net COâ uptake is reduced by about 70%. After ¹⁴COâ gas exchange, only

  8. Comparing actual evapotranspiration and plant water potential on a vineyard

    NASA Astrophysics Data System (ADS)

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

    2011-11-01

    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.

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

    PubMed

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

    2012-11-30

    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

  10. Differential decomposition of arbuscular mycorrhizal fungal hyphae and glomalin

    Microsoft Academic Search

    Peter D Steinberg; Matthias C Rillig

    2003-01-01

    Arbuscular mycorrhizal fungi (AMF) are obligate symbionts of most higher plants. In addition to being a major component of soil microbial biomass, AMF hyphae produce glomalin, a recalcitrant glycoproteinaceous substance highly correlated with soil aggregate water stability. This study addresses the lack of knowledge concerning the decomposition of hyphae and glomalin. We used an experimental design that exploited the lack

  11. Integrated operation of drinking water treatment plant at Amsterdam water supply

    Microsoft Academic Search

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

    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

  12. Stomatal behavior and water relations of waterlogged tomato plants.

    PubMed

    Bradford, K J; Hsiao, T C

    1982-11-01

    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. PMID:16662706

  13. Stomatal Behavior and Water Relations of Waterlogged Tomato Plants

    PubMed Central

    Bradford, Kent J.; Hsiao, Theodore C.

    1982-01-01

    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. PMID:16662706

  14. The rate of carbonic acid decomposition in sea water and its oceanographic significance 

    E-print Network

    Park, Kilho

    1957-01-01

    , The role of boron in the buffer mechanism of sea water was dis- cussed by Revelle and Moberg (1934). For borate ion in sea water, the following relatio~ existsc 22 2t3 2 3 2332 + 32 (17) where ZH3BO3 ? CHpO t CH 3B03. From equation (17...) it is feasible to calcu ate the concentration of borate ion at various pH values, and further, its role on the buffer system in sea water, Als2, from equation (17) it is noticed that any variation of the total boron concentration in sea water changes...

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

    Microsoft Academic Search

    T. A. Kimmell; J. A. Veil

    2009-01-01

    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

  16. Department of Mechanical and Nuclear Engineering Spring 2012 Automatic Plant Watering System

    E-print Network

    Demirel, Melik C.

    PENNSTATE Department of Mechanical and Nuclear Engineering Spring 2012 Automatic Plant Watering System Overview The goal of this project was to design an automatic plant watering system for commercial in the soil of household plants and delivery water to those plants on a need-only basis. The overall design

  17. Tragedy of the commons in plant water use

    NASA Astrophysics Data System (ADS)

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

    2006-06-01

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

  18. 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...

  19. 7. VIEW OF WATER TREATMENT PLANT, ADJACENT TO THE COAL ...

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

    7. VIEW OF WATER TREATMENT PLANT, ADJACENT TO THE COAL CONVEYOR; IN THE DISTANCE IS THE FREQUENCY CHANGER HOUSE, WHICH IS ATTACHED TO SWITCH HOUSE NO. 1; LOOKING WEST. - Commonwealth Electric Company, Fisk Street Electrical Generating Station, 1111 West Cermak Avenue, Chicago, Cook County, IL

  20. Application of fuzzy causal networks to waste water treatment plants

    Microsoft Academic Search

    Y. C. Huang; X. Z. Wang

    1999-01-01

    A graphical model, the extended fuzzy causal network is introduced and applied to a case study of waste water treatment plants. The structure of the network is developed using parameter sensitivity studies and the relationships between connected parameters are obtained using a learning approach adapted from fuzzy neural networks. The graphical model is shown to be able to translate the

  1. Fetal loss and work in a waste water treatment plant

    Microsoft Academic Search

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

    1984-01-01

    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

  2. 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...

  3. Solidification\\/Stabilization of Power Plants Wastes Potential Water Pollutants

    Microsoft Academic Search

    Aleksandra Kosti?-Pulek; Svetlana Popov

    The intensive firing of coal in power plants can harm the environment. The problems are caused by the emission of solid particles, sulphur oxides, nitrogen oxides, carbon monoxide, carbon dioxide to the atmosphere, as well as by pollution of the surrounding waters and the degradation of the land due to the disposition of the solid wastes: fly ash, bottom ash

  4. PILOT PLANT PROJECT FOR REMOVING ORGANIC SUBSTANCES FROM DRINKING WATER

    EPA Science Inventory

    This report describes research on the European practice of preozonation of water to modify naturally occurring organics, followed by bacteria activated carbon (BAC) adsorption to remove trihalomethane precursors. A 100-gal/min pilot plant was designed, constructed and operated to...

  5. Performance of a hotel chilled water plant with cool storage

    Microsoft Academic Search

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

    1999-01-01

    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

  6. Measurement of plant water status by the pressure chamber technique

    Microsoft Academic Search

    Neil C. Turner

    1988-01-01

    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

  7. Operational margin monitoring system for boiling water reactor power plants

    Microsoft Academic Search

    S. Fukutomi; Y. Takigawa; H. Namba

    1992-01-01

    This paper reports on an on-line operational margin monitoring system which has been developed for boiling water reactor power plants to improve safety, reliability, and quality of reactor operation. The system consists of a steady-state core status prediction module, a transient analysis module, a stability analysis module, and an evaluation and guidance module. This system quantitatively evaluates the thermal margin

  8. Energy efficient water utilization systems in process plants

    Microsoft Academic Search

    Miguel Bagajewicz; Hernán Rodera; Mariano Savelski

    2002-01-01

    This paper introduces a new approach for the design of water utilization networks featuring minimum freshwater usage and minimum utility consumption in process plants. The procedure is confined to treat the single pollutant case, and it is based on a linear programming formulation that relies on necessary conditions of optimality and a heat transshipment model. An LP model is first

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

    SciTech Connect

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

    2006-06-30

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

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

    PubMed Central

    Assouline, Shmuel; Or, Dani

    2013-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2008-05-01

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

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

    E-print Network

    Florida, University of

    , GRAETZ, AND K. R. REDDY2 ABSTRACT Using water hyacinth [Eichhornia crassipes (Mart.) Solms water hyacinth biomass,with either low or high N tissue con- tent, were added to soil to evaluate C that have received critical evaluation include aquatic plants such as water hyacinth (Eichhornia crassipes

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

    SciTech Connect

    Beigel`drud, G.M.

    1995-03-01

    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 with an electrochemical method, which was chosen as the most efficient path towards removal.

  14. Two-point Dixon technique for water-fat signal decomposition with B0 inhomogeneity correction.

    PubMed

    Coombs, B D; Szumowski, J; Coshow, W

    1997-12-01

    To separate water and lipid resonance signals by phase-sensitive MRI, a two-point Dixon (2PD) reconstruction is presented in which phase-unwrapping is used to obtain an inhomogeneity map based on only in-phase and out-of-phase image data. Two relaxation-weighted images, a "water image" and a "fat image," representing a two-resonance peak model of proton density, are output. The method is designed for T1- or density-weighted spin-echo imaging; a double-echo scheme is more appropriate for T2-weighted spin-echo imaging. The technique is more time-efficient for clinical fat-water imaging than 3PD schemes, while still correcting for field inhomogeneity. PMID:9402188

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

    NASA Astrophysics Data System (ADS)

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

    2013-04-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-09-01

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

  17. Catalytic Links Among the Water-Gas shift, Water-Assisted Formic Acid Decomposition, and Methanol Steam Reforming Reactions over Pt PromotedTthoria

    SciTech Connect

    Jacobs,G.; Patterson, P.; Graham, U.; Crawford, A.; Dozier, A.; Davis, B.

    2005-01-01

    Implied in the proposed water-gas shift (WGS) mechanisms for Pt/ceria and Pt/thoria catalysts is the presumption that reduced defect centers are formed on the surface. This X-ray absorption near-edge spectroscopy study provides direct results indicating that Pt facilitates reduction in the surface shell of thoria. Mechanistic arguments from in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) are provided suggesting that the active sites for WGS, water-assisted formic acid decomposition, and methanol steam reforming are associated with oxygen-deficient centers. In all cases, a high H{sub 2}O/reactant (i.e., carbon monoxide, formic acid, or methanol) ratio was used. For WGS, CO reacted with type II bridging OH groups at reduced centers to generate surface formate intermediates, the decomposition of which is suggested to be the rate-limiting step by the observation of a normal kinetic isotope effect (NKIE) associated with the formate coverage as monitored by DRIFTS under steady-state conditions using CO + H{sub 2}O and CO + D{sub 2}O feeds. The same NKIE was observed in steady-state reaction tests. Formic acid dissociated on the surface of thoria to yield the same surface formate species as observed when CO adsorbs. An identical NKIE associated with formate decomposition was observed when switching from a feed containing HCOOH + H{sub 2}O and DCOOH + H{sub 2}O, establishing two important commonalities: (1) similarity in the mechanistic pathway and (2) importance of the role of type II bridging OH groups at reduced centers in the catalysis. Methanol steam reforming likely proceeded through a mechanism involving adsorption at reduced centers to generate type II methoxy species, with subsequent conversion to formate, unidentate carbonate, and finally CO{sub 2}. The higher NKIE when switching between H-labeled and D-labeled feeds suggests that conversion of methoxy species to formate may be the rate-limiting step. The methanol steam reforming reaction was selective to CO{sub 2} at low conversion, but CO selectivity increased at higher conversions, suggesting competition with the secondary reaction of reverse WGS at higher temperature. Pt/thoria was more selective at higher conversion for CO{sub 2} than a similarly loaded Pt/ceria catalyst. These results suggest that from a mechanistic standpoint, the two materials are virtually analogs of one another.

  18. 78 FR 64493 - Notice of Complaint; Frankfort Electric and Water Plant Board; Cities of Barbourville, Bardstown...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-29

    ...consolidated)] Notice of Complaint; Frankfort Electric and Water Plant Board; Cities of Barbourville, Bardstown, Bardwell...Procedure, 18 CFR 385.206, Frankfort Electric and Water Plant Board and the Cities of Barbourville, Bardstown,...

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

    E-print Network

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

    1982-01-01

    , measurements of plant water stress are fundamental in understanding how the environment affects plant performance. This in turn will facilitate the irrigator to have very precise water control and to determine optimum irrigation quantities. This research...

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

    NASA Technical Reports Server (NTRS)

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

    1996-01-01

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

  1. Hydraulic redistribution may stimulate decomposition

    Microsoft Academic Search

    Zachary T. Aanderud; James H. Richards

    2009-01-01

    Roots influence root litter decomposition through multiple belowground processes. Hydraulic lift or redistribution (HR) by\\u000a plants is one such process that creates diel drying–rewetting cycles in soil. However, it is unclear if this phenomenon influences\\u000a decomposition. Since decomposition in deserts is constrained by low soil moisture and is stimulated when dry soils are rewetted,\\u000a we hypothesized that diel drying–rewetting, via

  2. LEA proteins during water stress: not just for plants anymore.

    PubMed

    Hand, Steven C; Menze, Michael A; Toner, Mehmet; Boswell, Leaf; Moore, Daniel

    2011-01-01

    Late embryogenesis abundant (LEA) proteins are extremely hydrophilic proteins that were first identified in land plants. Intracellular accumulation is tightly correlated with acquisition of desiccation tolerance, and data support their capacity to stabilize other proteins and membranes during drying, especially in the presence of sugars like trehalose. Exciting reports now show that LEA proteins are not restricted to plants; multiple forms are expressed in desiccation-tolerant animals from at least four phyla. We evaluate here the expression, subcellular localization, biochemical properties, and potential functions of LEA proteins in animal species during water stress. LEA proteins are intrinsically unstructured in aqueous solution, but surprisingly, many assume their native conformation during drying. They are targeted to multiple cellular locations, including mitochondria, and evidence supports that LEA proteins stabilize vitrified sugar glasses thought to be important in the dried state. More in vivo experimentation will be necessary to fully unravel the multiple functional properties of these macromolecules during water stress. PMID:21034219

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

    E-print Network

    Kalisek, Danielle

    2011-01-01

    water of El Paso can be a landscaper?s nightmare. But scientists at the Texas AgriLife Research and Extension Center at El Paso are researching plant and turf tolerance to be#14;er adapt to this climate and saline water situation. In addition..., reclaimed wastewater is being used on larger public areas as a way to reuse water resources and conserve potable, or drinkable, freshwater supplies. Dr. Ari Michelsen, El Paso center director, recognizes the importance of water as well as managing...

  4. Photocatalytic decomposition of azo-dye acid black 1 in water over modified titanium dioxide

    Microsoft Academic Search

    Joanna Grzechulska; Antoni Waldemar Morawski

    2002-01-01

    The photocatalytic oxidation of an azo-dye acid black 1 (AB1) in water has been investigated over modified titanium dioxide (Tytanpol A11, “Police” Chemical Factory, Poland). The effect of operational parameters, i.e. pH of the solution, photocatalyst content, initial dye concentration on the photocatalytic process has been examined. It can be stated that the complete removal of color, after selection of

  5. Water Detoxification: Photocatalytic Decomposition of Phenol on Au\\/TiO 2

    Microsoft Academic Search

    Anna Dobosz; Andrzej Sobczy?ski

    2001-01-01

    Summary.  ?Photodeposition of gold on TiO2 was conducted in situ in the photoreactor used for the reaction of phenol photodestruction. The Au\\/TiO2 system shows better photocatalytic properties in the destruction of phenol contaminants in water than pure TiO2. The gold cocatalyst prevents also the decrease of the rate of the photocatalytic reaction at higher phenol concentration\\u000a observed for pure TiO2. Hydroquinone,

  6. Effect of Ultrasound on Sludge from Water Treatment Plant

    NASA Astrophysics Data System (ADS)

    Kim, Young U.; Ha, Junsoo; Yoon, Ki Yong; Lee, Seung-Hyun

    2004-10-01

    In this study, we investigated the effect of ultrasound on the reduction in the amount of heavy metals and the dewaterability of sludge from a water treatment plant. The investigation involved laboratory experiments, which were conducted under different conditions, including the energy levels of ultrasonic waves and treatment time. Results of the study show that ultrasound reduces the amount of heavy metals and enhances the dewaterability of sludge significantly. The degree of enhancement varies with ultrasonic energy and treatment time.

  7. Nitrogen Removal from Eutrophicated Water by Aquatic Plants

    Microsoft Academic Search

    Olga Babourina; Zed Rengel

    \\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.

  8. Accident source terms for light-water nuclear power plants

    Microsoft Academic Search

    Soffer

    1993-01-01

    This paper presents a discussion of current U.S. Nuclear Regulatory Commission (NRC) activities regarding the proposed revision of accident source terms for light-water nuclear power plants, particularly since the issuance of draft revised source terms in July 1992. The NRC's current reactor site criteria require that an accident fission product release within containment, or [open quotes]source term,[close quotes] be postulated

  9. Water treatment plant simulation program, version 1. 21, user's manual

    SciTech Connect

    Not Available

    1992-06-01

    The User's Manual for Version 1.21 of the Water Treatment Plant Simulation Program has been prepared to provide a basic understanding of (1) how to operate the program, and (2) the underlying assumptions and equations that are used to calculate the removal of natural organic matter and the formation of disinfection by-products. The manual represents the first public release of the program.

  10. Analysis of Piping Systems for Life Extension of Heavy Water Plants in India

    Microsoft Academic Search

    Rajesh K. Mishra; R. S. Soni; H. S. Kushwaha; V. Venkat Raj

    2002-01-01

    Heavy water production in India has achieved many milestones in the past. Two of the successfully running heavy water plants are on the verge of completion of their design life in the near future. One of these two plants, situated at Kota, is a hydrogen sulfide based plant and the other one at Tuticorin is an ammonia-based plant. Various exercises

  11. 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...

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

    Microsoft Academic Search

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

    2007-01-01

    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

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

    Microsoft Academic Search

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

    2006-01-01

    Increased livestock densities near artificial watering sites create disturbance gradients called piospheres. We studied responses of alien and native annual plants and native perennial plants within 9 piospheres in the Mojave Desert of North America. Absolute and proportional cover of alien annual plants increased with proximity to watering sites, whereas cover and species richness of native annual plants decreased. Not

  14. Protecting against water loss: analysis of the barrier properties of plant cuticles

    Microsoft Academic Search

    Markus Riederer; Lukas Schreiber

    2001-01-01

    The cuticle is the major barrier against uncontrolled water loss from leaves, fruits and other primary parts of higher plants. More than 100 mean values for water permeabilities determined with isolated leaf and fruit cuticles from 61 plant species are compiled and discussed in relation to plant organ, natural habitat and morphology. The maximum barrier prop- erties of plant cuticles

  15. Benchmarking of municipal waste water treatment plants (an Austrian project).

    PubMed

    Lindtner, S; Kroiss, H; Nowak, O

    2004-01-01

    An Austrian research project focused on the development of process indicators for treatment plants with different process and operation modes. The whole treatment scheme was subdivided into four processes, i.e. mechanical pretreatment (Process 1), mechanical-biological waste water treatment (Process 2), sludge thickening and stabilisation (Process 3) and further sludge treatment and disposal (Process 4). In order to get comparable process indicators it was necessary to subdivide the sample of 76 individual treatment plants all over Austria into five groups according to their mean organic load (COD) in the influent. The specific total yearly costs, the yearly operating costs and the yearly capital costs of the four processes have been related to the yearly average of the measured organic load expressed in COD (110 g COD/pe/d). The specific investment costs for the whole treatment plant and for Process 2 have been related to a calculated standard design capacity of the mechanical-biological part of the treatment plant expressed in COD. The capital costs of processes 1, 3 and 4 have been related to the design capacity of the treatment plant. For each group (related to the size of the plant) a benchmark band has been defined for the total yearly costs, the total yearly operational costs and the total yearly capital costs. For the operational costs of the Processes 1 to 4 one benchmark ([see symbol in text] per pe/year) has been defined for each group. In addition a theoretical cost reduction potential has been calculated. The cost efficiency in regard to water protection and some special sub-processes such as aeration and sludge dewatering has been analysed. PMID:15553485

  16. Role of chromatin in water stress responses in plants

    PubMed Central

    Han, Soon-Ki; Wagner, Doris

    2014-01-01

    As sessile organisms, plants are exposed to environmental stresses throughout their life. They have developed survival strategies such as developmental and morphological adaptations, as well as physiological responses, to protect themselves from adverse environments. In addition, stress sensing triggers large-scale transcriptional reprogramming directed at minimizing the deleterious effect of water stress on plant cells. Here, we review recent findings that reveal a role of chromatin in water stress responses. In addition, we discuss data in support of the idea that chromatin remodelling and modifying enzymes may be direct targets of stress signalling pathways. Modulation of chromatin regulator activity by these signaling pathways may be critical in minimizing potential trade-offs between growth and stress responses. Alterations in the chromatin organization and/or in the activity of chromatin remodelling and modifying enzymes may furthermore contribute to stress memory. Mechanistic insight into these phenomena derived from studies in model plant systems should allow future engineering of broadly drought-tolerant crop plants that do not incur unnecessary losses in yield or growth. PMID:24302754

  17. 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...

  18. Exotic plant communities shift water-use timing in a shrub-steppe ecosystem

    Microsoft Academic Search

    Andrew Kulmatiski; Karen H. Beard; John M. Stark

    2006-01-01

    Semiarid areas in the US have realized extensive and persistent exotic plant invasions. Exotics may succeed in arid regions by extracting soil water at different times or from different depths than native plants, but little data is available to test this hypothesis. Using estimates of root mass, gravimetric soil water, soil-water potential, and stable isotope ratios in soil and plant

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

    E-print Network

    Frandsen, Jannette B.

    A Cold Water Pipe for an OTEC Pilot Plant: Design Considerations Kara Silver Abstract Ocean Thermal (HDPE) Cold Water Pipe (CWP) for a floating OTEC pilot plant, presumably in Hawaiian waters to develop this technology, pilot plants are needed to gather operational data, reduce engineering risks

  20. Reconstructing plant root area and water uptake profiles Kiona Ogle1

    E-print Network

    West, Mike

    Reconstructing plant root area and water uptake profiles by Kiona Ogle1 , Robert L. Wolpert2 Abstract A major challenge in plant ecology is quantifying how roots interact with the soil to obtain water and nutrients. Stable isotope analysis of hydrogen and oxygen bound in plant and soil water is one of the best

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

    PubMed

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

    2015-01-01

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

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

    SciTech Connect

    Krofta, M.; Wang, L.K.

    1988-06-15

    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.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  4. Co-variations in litter decomposition, leaf traits and plant growth in species from a Mediterranean old-field succession

    Microsoft Academic Search

    E. KAZAKOU; D. VILE; B. SHIPLEY; C. GALLET; E. GARNIER

    2006-01-01

    Summary 1. A growing consensus is developing that the impact of species on ecosystem properties is mediated, at least partially, by the traits of their component species. A previous study demonstrated that the field decomposition of complex litters produced by different communities of a Mediterranean successional sere was related to the average trait value of these communities. Here we scale

  5. Emergent plant decomposition and sedimentation: response to sediments varying in texture, phosphorus content and frequency of deposition

    Microsoft Academic Search

    Sharon M Vargo; Robert K Neely; Stephen M. Kirkwood

    1998-01-01

    The impact of sedimentation on the decay of Typha latifolia, Typha angustifolia and Sparganium eurycarpum litter was evaluated in two Michigan wetlands. In one wetland, T. latifolia decay was studied among replicates of three treatments (unsedimented treatment, one-time sediment application (sandy loam) and multiple sediment applications). In the second wetland, decomposition of T. angustifolia and S. eurycarpum, exposed to phosphorus-enriched

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

    PubMed

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

    2010-07-01

    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

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

    PubMed Central

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

    2010-01-01

    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. PMID:20639342

  8. Mercury Bioaccumulation Potential from Wastewater Treatment Plants in Receiving Waters

    NASA Astrophysics Data System (ADS)

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

    2008-12-01

    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.

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

    Microsoft Academic Search

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

    2006-01-01

    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

  10. Water Transport in Crop Plants with Special Reference to Rice: Key to Crop Production Under Global Water Crisis

    Microsoft Academic Search

    Sanjay Singh; T. N. Singh; J. S. Chauhan

    2009-01-01

    The knowledge of water flow in agricultural plant species is vital for successful crop production and its management; therefore, investigations were carried out on water transport in rice, one of the most important cereal crops of the world. In these studies, five distinct pieces of evidence of the existence of, at whole-plant level, a previously unappreciated mechanism of water transport

  11. Polyfluorinated compounds in waste water treatment plant effluents and surface waters along the River Elbe, Germany

    Microsoft Academic Search

    Lutz Ahrens; Sebastian Felizeter; Renate Sturm; Zhiyong Xie; Ralf Ebinghaus

    2009-01-01

    Polyfluorinated compounds (PFCs) were investigated in waste water treatment plant (WWTP) effluents and surface waters of the River Elbe from samples collected in 2007. Concentrations of various PFCs, including C4–C8 perfluorinated sulfonates (PFSAs), C6 and C8 perfluorinated sulfinates, 6:2 fluorotelomer sulfonate, C5–C13 perfluorinated carboxylic acids (PFCAs), C4 and C8 perfluoroalkyl sulfonamides and 6:2, 8:2 and 10:2 unsaturated fluorotelomercarboxylic acids were

  12. Enhanced photocatalytic activity of TiO 2 nanofibers and their flexible composite films: Decomposition of organic dyes and efficient H 2 generation from ethanol-water mixtures

    Microsoft Academic Search

    Ming-Chung Wu; András Sápi; Anna Avila; Mária Szabó; Jussi Hiltunen; Mika Huuhtanen; Géza Tóth; Ákos Kukovecz; Zoltán Kónya; Riitta Keiski; Wei-Fang Su; Heli Jantunen; Krisztián Kordás

    2011-01-01

    TiO2 nanofibers decorated with Pt and Pd nanoparticles have been synthesized and studied in various photocatalytic processes.\\u000a Excellent photocatalytic behavior in the decomposition of organic dyes in water, degradation of organic stains on the surface\\u000a of flexible freestanding cellulose\\/catalyst composite films and in generation of hydrogen from ethanol using both suspended\\u000a and immobilized catalysts are demonstrated. The performance of the

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

    SciTech Connect

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

    1991-05-01

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

  14. Comparative Resistance of the Soil and the Plant to Water Transport 1

    PubMed Central

    Blizzard, Wayne E.; Boyer, John S.

    1980-01-01

    The resistances to liquid water transport in the soil and plant were determined directly and simultaneously from measurements of soil, root, and leaf water potentials and the flux of water through the soil-plant system to the sites of evaporation in the leaf. For soybean (Merr.) transporting water at a steady rate, water potential differences between soil and root were smaller than between root and leaf over the range of soil water potentials from ?0.2 to ?11 bars. As soil water was depleted, water flow through the soil and plant decreased to one-tenth the maximum rate, but both the soil resistance and plant resistance increased. The plant resistance remained larger than the soil resistance over the entire range of soil water availability. Previous suggestions that the soil is the major resistance have ignored the increase in plant resistance and/or assumed root densities that were too low. PMID:16661531

  15. Integrated optimization of a waste water treatment plant using statistical analysis

    Microsoft Academic Search

    Frank Halters; Edwin Zondervan; Andre de Haan

    2010-01-01

    In this research, a waste water treatment plant is systematically optimized. The waste water treatment plant is used to remove aluminium from waste water using precipitation, flocculation and flotation. In total 40 variables influence the combined unit. After systematic selection, the number of variables was reduced to six: the waste water flow, pH, agitation velocity, amount of poly-electrolyte, amount of

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

    ERIC Educational Resources Information Center

    South Dakota Dept. of Environmental Protection, Pierre.

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

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

    NASA Astrophysics Data System (ADS)

    Sudnitsyn, I. I.

    2008-01-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2005-12-01

    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.

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

    Code of Federal Regulations, 2010 CFR

    2010-04-01

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

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

    Code of Federal Regulations, 2012 CFR

    2012-04-01

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

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

    Code of Federal Regulations, 2011 CFR

    2011-04-01

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

  2. 18 CFR 420.51 - Hydroelectric power plant water use charges.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

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

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

    Code of Federal Regulations, 2014 CFR

    2014-04-01

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

  4. Lignocellulose decomposition by microbial secretions

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  5. Comparison of trace metals in intake and discharge waters of power plants using clean techniques

    SciTech Connect

    Salvito, D.T. [Public Service Electric and Gas Co., Maplewood, NJ (United States). Maplewood Testing Services; Allen, H.E. [Univ. of Delaware, Newark, DE (United States). Dept. of Civil Engineering

    1995-12-31

    In order to determine the impact to receiving waters of trace metals potentially discharged from a once-through, non-contact cooling water system from a power plant, a study was conducted utilizing clean sampling and analytical techniques for a series of metals. Once-through, non-contact cooling water at power plants is frequently discharged back to the fresh or saline waterbody utilized for its intake water. This water is used to cool plant condensers. Intake and discharge data were collected and evaluated using paired t-tests. Study results indicate that there is no measurable contribution of metals from non-contact cooling water from this power plant.

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

    Microsoft Academic Search

    D. D. French

    1988-01-01

    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

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

    PubMed Central

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

    2013-01-01

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

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

    SciTech Connect

    Waewcharoen, Sribudh; Boonyapibanwong, Supachai; Koonprasert, Sanoe [Department of Mathematics, King Mongkut's University of Technology, North Bangkok (Thailand)

    2008-09-01

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

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

    PubMed

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

    2014-06-17

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

  10. Rapid In Situ Identification of Source Water and Leaf Water in a Variety of Plant Species and Functional Types

    NASA Astrophysics Data System (ADS)

    Still, C. J.; Hu, J.; Berkelhammer, M. B.; Barnard, H. R.; Rahn, T.; Hsiao, G.; Raudzens Bailey, A.; Noone, D. C.

    2011-12-01

    Plant rooting distributions and use of soil water resources are important determinants of ecological and hydrological function. The isotope composition of plant xylem water can be used to infer soil water source variations, in particular differences among species and plant functional types. We report here on dynamics in the oxygen and hydrogen isotope composition of plant and soil water pools and fluxes within the Manitou Experimental Forest in the Colorado Rockies. For this work, we used multiple in situ laser-based spectroscopic analyzers to collect isotope data on soil water, leaf water, stem water, transpiration water, and canopy vapor from multiple heights in the canopy. Using an Induction Module - Cavity Ring-Down Spectroscopy system, which extracts and analyzes soil and plant samples in a few minutes, we measured soil and plant water isotopic composition from multiple soil depths and plant species at several points throughout the growing season. Stem (source) water isotopic composition varied greatly among the various plant species and functional types (pine trees, shrubs, forbs, grasses), broadly in agreement with expected plant rooting depths. The steady-state isotopic composition of leaf transpiration, another proxy of source water, was also consistent with this variation by plant functional type and rooting depth. Leaf water generally followed these patterns, but pine needles exhibited dramatic isotopic gradients along the needle length, with hydrogen isotope gradients of close to 100 per mil from leaf base to tip. We also introduced an isotopic label in two pines of different sizes (that were previously instrumented with sapflow probes and dendrometers) to further identify the pathways and pace of water flow though the trees. These results demonstrate the complex interactions between multiple source and fluxes of water, and that simple ecosystem isotope models, while generally valid, require careful evaluation as high-frequency and in situ isotopic data become more widely available.

  11. Pull, Push and Evaporate: The Role of Surfaces in Plant Water Transport

    Microsoft Academic Search

    Anita Roth-Nebelsick

    Water is of fundamental significance for plant life. One fundamental aspect is that water represents an important environmental\\u000a factor. Rain, fog and mist affect irradiation absorbed by a plant and the environmental temperature. Water is therefore a\\u000a climate-related parameter. It also acts as a factor which influences the immediate surroundings of a plant. For example, plants\\u000a which live in swamp

  12. Influence of decomposition on chemical properties of plant- and manure-derived dissolved organic matter and sorption to goethite.

    PubMed

    Hunt, James F; Ohno, Tsutomu; He, Zhongqi; Honeycutt, C Wayne; Dail, D Bryan

    2007-01-01

    Sorption of dissolved organic matter (DOM) plays an important role in maintaining the fertility and quality of soils in agricultural ecosystems. Few studies have examined the effects of decomposition on DOM sorption and chemical characteristics. This study investigated the sorption to goethite (alpha-FeOOH) of fresh and decomposed hydrophilic (HPL) and hydrophobic (HPB) DOM fractions extracted from the shoots and roots of crimson clover (Trifolium incarnatum L.), corn (Zea mays L.), soybean [Glycine max (L.) Merr.], hairy vetch (Vicia villosa L.), and dairy and poultry manures. Sorption was positively related to apparent molecular weight (MWAP), aromaticity as measured by absorptivity at 280 nm, and phenolic acid content. A 10-d laboratory microbial decomposition of the source organic matter generally increased the sorption of the extracted DOM onto goethite. The decomposition effect on sorption was greater for the HPL fractions than for the HPB fractions. There was a decrease in the MWAP values of the DOM samples following sorption to goethite. In many cases the reduction in MWAP was large, indicating a strong preference by goethite for the higher MWAP DOM fractions. The results of this laboratory-based research demonstrate that microbial processes affect the chemical characteristics of DOM which may affect the distribution of soil organic C pools. PMID:17215221

  13. Decomposition of sinigrin by methanol\\/ammonia\\/water treatment in model systems and mustard ( Brassica nigra L.) seed meal

    Microsoft Academic Search

    Radomír Pechá?ek; Jan Velíšek; Ji?í Davídek

    2000-01-01

    Sinigrin (allylglucosinolate) was stored at 20??°C, 40??°C, and 60??°C in solutions containing 10% ammonia in 95% methanol\\u000a (CH3OH\\/NH3\\/H2O). The individual samples were analyzed for their contents of sinigrin, its decomposition product allyl isothiocyanate (AITC)\\u000a and other reaction products. The major reaction products were allyl thiourea, methyl ester of N-allyl thiocarbamoyl acid and allyl cyanide. A newly identified decomposition product of

  14. Removal of fluoride from water by five submerged plants.

    PubMed

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

    2012-08-01

    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

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

    SciTech Connect

    Not Available

    1990-01-01

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

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

    NASA Astrophysics Data System (ADS)

    Tardieu, F.

    2012-04-01

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

  17. LU Decomposition

    NSDL National Science Digital Library

    Fitchett, Stephanie

    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.

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

    SciTech Connect

    McAnally, A.S.

    1989-01-01

    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.)

  19. Stable Carbon Isotopes As Indicators of Plant Water Use Efficiency

    NASA Astrophysics Data System (ADS)

    Powers, E. M.; Marshall, J. D.; Ubierna Lopez, N.

    2007-12-01

    Stable carbon isotopes have been utilized to better understand how environmental variables influence the efficiency of photosynthesis, specifically what factors limit the uptake and absorption of CO2 during photosynthesis. An understanding of the controls over both gas exchange and stomatal conductance can provide an explanation for the possible environmental influences on plant WUE. The ?13C of extractive-free wood was used as an index of plant water use efficiency at Mica Creek Experimental Watershed, Shoshone County, ID. The ?13C values of tree rings were used to determine the effects of clear cut and partial cut harvesting practices, the effect of elevation, and species differences in intrinsic water use efficiency (WUE) among coniferous species including: Thuja plicata, Larix occidentalis, Picea engelmannii, Pseudotsuga menziesii, Abies lasiocarpa, and Abies grandis. We found significant effects of harvest treatments (p=0.0197), elevation (p= 0.0268), and species (p<0.001) on tree ?13C. The significantly more enriched isotopic signatures observed in Thuja plicata (?13C = -23.37 ±0.17‰), indicate that it is a more water use efficient species compared to Larix occidentalis (?13C = -25.66 ±0.43‰), and Abies grandis (?13C = -25.83 ±0.15‰). There was also an overall trend of ?13C enrichment with elevation. The isotopic composition of tree rings has been estimated to increase by 0.003 ‰ per meter of elevation gain, which may be related to a decrease in soil moisture with elevation. Finally, the mean ?13C values observed on partial cut (?13C = -24.73 ±0.10‰) and clear cut treatments (?13C = -24.45 ±0.29‰) were significantly more enriched than the mean value for the control treatment (?13C = -25.25 ±0.19‰). The more enriched isotopic signatures observed on the harvested treatments indicate that the trees are more water use efficient, which may be a result of increased photosynthetic capacity with an increase in the availability of water, foliar nitrogen, and light to individual trees on the harvested treatments. The reduction of stand density through harvesting may reduce the transpirational water losses on a stand level, thus increasing the water availability for individual trees.

  20. Macroalgal-mediated transfers of water column nitrogen to intertidal sediments and salt marsh plants

    E-print Network

    Boyer, Katharyn

    in the subtidal zone of estuaries. For example, phytoplankton and macro- algae suspended in the water column algae. In the 6-week experiment, macroalgal biomass increased from initial levels in the lower density treatments but all algae lost N mass, probably through both leakage and decomposition. With all densities

  1. Assessment of the suitability of agricultural waste water for geothermal power plant cooling in the Imperial Valley. 1: Water quality

    Microsoft Academic Search

    W. F. Morris; L. P. Rigdon

    1981-01-01

    Evaluation of the quality of agricultural waste water is the first step in assessing the suitability of agricultural waste water for geothermal power plant cooling. Samples of agricultural waste water from the New and Alamo rivers located in the Imperial Valley of California were analyzed. Determinations of standard water quality parameters, solids content, and inorganic compositions of the solids were

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

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

    ERIC Educational Resources Information Center

    Grenville, H. W.

    1983-01-01

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

  4. Unravelling the molecular cues of plant adaptation or survival to water deficit

    Microsoft Academic Search

    A. Ambrosone; A. Costa; L. Frusciante; L. Monti; A. Leone; S. Grillo

    When experiencing water deficit, glycophyte plants undergo physiological and biochemical changes aimed at limiting cellular damages and rescuing a new cellular homeostasis. Discriminate irreversible cell injury from adaptive rearrangements to water stress, is quite critical since only the latter plant response is compatible with active growth and development sustaining, ultimately, plant yield. An up-dated view of the molecular basis of

  5. Toxicity reduction evaluation at the Patapsco Waste Water Treatment plant. Final report, April 1986September 1987

    Microsoft Academic Search

    J. A. Botts; J. W. Braswell; E. C. Sullivan; W. L. Goodfellow; B. D. Sklar

    1988-01-01

    The EPA and the City of Baltimore (City) entered into a cooperative agreement to perform a TRE research study at the City's Patapsco Waste Water Treatment Plant (Patapsco WWTP). The Patapsco WWTP TRE represents one of the first case histories of a toxics management program at a municipal waste-water treatment plant. The study characterized treatment plant influent and operations data

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

    NASA Astrophysics Data System (ADS)

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

    2012-04-01

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

  7. [Characteristics of dissolved organic carbon release under inundation from typical grass plants in the water-level fluctuation zone of the Three Gorges Reservoir area].

    PubMed

    Tan, Qiu-Xia; Zhu, Boi; Hua, Ke-Ke

    2013-08-01

    The water-level fluctuation zone of the Three Gorges Reservoir (TGR) exposes in spring and summer, then, green plants especially herbaceous plants grow vigorously. In the late of September, water-level fluctuation zone of TGR goes to inundation. Meanwhile, annually accumulated biomass of plant will be submerged for decaying, resulting in organism decomposition and release a large amount of dissolved organic carbon (DOC). This may lead to negative impacts on water environment of TGR. The typical herbaceous plants from water-level fluctuation zone were collected and inundated in the laboratory for dynamic measurements of DOC concentration of overlying water. According to the determination, the DOC release rates and fluxes have been calculated. Results showed that the release process of DOC variation fitted in a parabolic curve. The peak DOC concentrations emerge averagely in the 15th day of inundation, indicating that DOC released quickly with organism decay of herbaceous plant. The release process of DOC could be described by the logarithm equation. There are significant differences between the concentration of DOC (the maximum DOC concentration is 486.88 mg x L(-1) +/- 35.97 mg x L(-1) for Centaurea picris, the minimum is 4.18 mg x L(-1) +/- 1.07 mg x L(-1) for Echinochloacrus galli) and the release amount of DOC (the maximum is 50.54 mg x g(-1) for Centaurea picris, the minimum is 6.51 mg x g(-1) for Polygonum hydropiper) due to different characteristics of plants, especially, the values of C/N of herbaceous plants. The cumulative DOC release quantities during the whole inundation period were significantly correlated with plants' C/N values in linear equations. PMID:24191546

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

    SciTech Connect

    none,

    1981-05-01

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

  9. Water Relations in Soils as Related to Plant Communities in Ruby Valley, Nevada

    Microsoft Academic Search

    R. F. MILLER; F. A. BRANSON; I. S. MCQUEEN; C. T. SNYDER

    Distinct patterns of vegetation on ancient lake sediments in Ruby Valley, Nev., define differences in soil-water-plant relations resulting either from differences in depth to ground water or from differences in water-retention capacities of soils deriving water only from precipitation. In order of increasing depth to ground water, dominant plant species are Juncus balticus, Distichlis stricta, Potentilla fruticosa, Elymus cinereus, Sarcobatus

  10. Broccoli Plant Nitrogen, Phosphorus, and Water Relations at Field Scale and in Various Growth Media

    Microsoft Academic Search

    Hong Li; Humin Jiang; Tingxian Li

    2011-01-01

    High-value broccoli (Brassica oleracea var. italica L.) plant nutrition and water relations are not well understood. Our objectives were to examine the relations of plant nitrogen (N) and phosphorus (P) translocation and water holding in direct-seeded broccoli (cv. Everest) under different postseeding N treatments at field scale and with different growth media types and water supply levels under greenhouse conditions.

  11. Kinetics of electron-induced decomposition of CF{sub 2}Cl{sub 2} coadsorbed with water (ice): A comparison with CCl{sub 4}

    SciTech Connect

    Faradzhev, N.S.; Perry, C.C.; Kusmierek, D.O.; Fairbrother, D.H.; Madey, T.E. [Department of Physics and Astronomy, and Laboratory for Surface Modification, Rutgers, State University of New Jersey, Piscataway, New Jersey 08854-8019 (United States); Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218 (United States); Department of Physics and Astronomy, and Laboratory for Surface Modification, Rutgers, State University of New Jersey, Piscataway, New Jersey 08854-8019 (United States); Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218 (United States); Department of Physics and Astronomy, and Laboratory for Surface Modification, Rutgers, State University of New Jersey, Piscataway, New Jersey 08854-8019 (United States)

    2004-11-01

    The kinetics of decomposition and subsequent chemistry of adsorbed CF{sub 2}Cl{sub 2}, activated by low-energy electron irradiation, have been examined and compared with CCl{sub 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{sub 2}Cl{sub 2} and CCl{sub 4} dissociation increase in an H{sub 2}O (D{sub 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{sub 2}O, using 180 eV incident electrons, are measured (using TPD) to be 1.0{+-}0.2x10{sup -15} cm{sup 2} for CF{sub 2}Cl{sub 2} and 2.5{+-}0.2x10{sup -15} cm{sup 2} for CCl{sub 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{sup -} and F{sup -} anions in the halocarbon/water films and production of H{sub 3}O{sup +}, CO{sub 2}, and intermediate compounds COF{sub 2} (for CF{sub 2}Cl{sub 2}) and COCl{sub 2}, C{sub 2}Cl{sub 4} (for CCl{sub 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.

  12. A Case Study of the DAF-based Drinking Water Treatment Plant in Korea

    Microsoft Academic Search

    Byeong-Yong Sohn; Tae-Joon Park; Byung Soo Oh; Soon-Buhm Kwon; Joon-Wun Kang

    2008-01-01

    Since 2003, a full-scale dissolved air flotation (DAF) process has been operated by the Korea Water Resources Corporation (K-Water) in the Songjeon drinking water treatment plant (SWTP). The SWPT was designed with an adaptable operation mode so that it is able to produce safe and stable drinking water, even when the raw water is in very poor condition. The adaptable

  13. Techniques and experimental approaches for the measurement of plant water status

    Microsoft Academic Search

    Neil C. Turner

    1981-01-01

    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

  14. Turion morphological responses to water nutrient concentrations and plant density in the submerged macrophyte Potamogeton crispus.

    PubMed

    Qian, Chang; You, Wenhua; Xie, Dong; Yu, Dan

    2014-01-01

    Asexual propagules are the dominant means of propagation in most submerged macrophytes. To improve the understanding of how water nutrient concentrations and population density influence the turion production of Potamogeton crispus L., the turions were planted in mesocosms with three water nutrient conditions (ambient lake water, high P and high N) and two plant density levels (4 and 15?turions m(-2)). After a 9-month experiment, the +P in the water column significantly increased the total turion number per plant under both of the plant density treatments. However, the +N in the water column did not affect the turion number per plant under low plant density. The +P in the water and high plant density significantly reduced the turion individual biomass. An examination of 3210 turion individuals from all treatments revealed that the increased water nutrient concentrations and plant density impacted the turion size by producing different stem diameters of individual turions. Most of the scale leaf morphological traits of the turions were significantly increased under higher water nutrients, but these traits were similar between the different plant density treatments. These results demonstrate that the water P concentration interacts with plant density, affecting both the production and traits of turions. PMID:25399866

  15. Tomato Plants Ectopically Expressing Arabidopsis CBF1 Show Enhanced Resistance to Water Deficit Stress1

    PubMed Central

    Hsieh, Tsai-Hung; Lee, Jent-turn; Charng, Yee-yung; Chan, Ming-Tsair

    2002-01-01

    A DNA cassette containing an Arabidopsis C repeat/dehydration-responsive element binding factor 1 (CBF1) cDNA and a nos terminator, driven by a cauliflower mosaic virus 35S promoter, was transformed into the tomato (Lycopersicon esculentum) genome. These transgenic tomato plants were more resistant to water deficit stress than the wild-type plants. The transgenic plants exhibited growth retardation by showing dwarf phenotype, and the fruit and seed numbers and fresh weight of the transgenic tomato plants were apparently less than those of the wild-type plants. Exogenous gibberellic acid treatment reversed the growth retardation and enhanced growth of transgenic tomato plants, but did not affect the level of water deficit resistance. The stomata of the transgenic CBF1 tomato plants closed more rapidly than the wild type after water deficit treatment with or without gibberellic acid pretreatment. The transgenic tomato plants contained higher levels of Pro than those of the wild-type plants under normal or water deficit conditions. Subtractive hybridization was used to isolate the responsive genes to heterologous CBF1 in transgenic tomato plants and the CAT1 (CATALASE1) was characterized. Catalase activity increased, and hydrogen peroxide concentration decreased in transgenic tomato plants compared with the wild-type plants with or without water deficit stress. These results indicated that the heterologous Arabidopsis CBF1 can confer water deficit resistance in transgenic tomato plants. PMID:12376629

  16. 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...

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

    NASA Astrophysics Data System (ADS)

    Caldeira, Ken; Cao, Long

    2015-04-01

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

  18. The use of plant-transpired water to monitor subsurface tritium contamination

    SciTech Connect

    Monheit, S.G. [Univ. of San Francisco, CA (United States)

    1995-12-31

    The experimental technique of sampling plant-transpired water to detect and monitor subsurface tritium contamination in soil water and groundwater was implemented in an area surrounding the National Tritium Labeling Facility (NTLF) at Lawrence Berkeley National Laboratory (LBNL). Data collected using the transpiration technique were compared with data collected by conventional soil water and groundwater sampling methods, to evaluate its application as an environmental monitoring tool. Tritium activity in the different ecological waters were compared for thirteen delineated areas. For statistical analysis of spatial and temporal trends, plant sampling stations were categorized as either deep or shallow rooted. Plant-transpired water samples were found to have consistently higher tritium activity than soil water or groundwater in leach localized area. Tritium activity in plant-transpired water diminished with distance from the emission source. Wet season plant-transpired water samples registered statistically significantly higher tritium activity than dry season samples, with the greatest variation from shallow rooted plants. The results of this study indicate that plant-transpired water sampling is a valuable tool in environmental monitoring and may be more sensitive in the detection of subsurface tritium contamination than conventional lysimeter or monitoring well sampling. Plant-transpired water sampling is a promising tool for investigating tritium distribution and concentration in contaminated soil water and groundwater.

  19. A quantitative application of the thermoelectric method for measuring water uptake by cotton plants 

    E-print Network

    Naghshineh-Pour, Bahman

    1965-01-01

    to exchange gases in photosynthesis without losing water. However, according to Meyer and Anderson (22), the fundamental effects of transpiration upon the plant are not to be sought in any hypo- thetical "advantages" of the process to the plant, but in its..., there was no, injury to. the plant and repeated measurements could be made on the same plant. The effect of soil and air temperature, air humidity, wind velocity, light intensity, rain showers, soil moisture conditions, irrigation water quality, and action...

  20. Effects of potassium deficiency on water relations and photosynthesis of the tomato plant

    Microsoft Academic Search

    M. H. Behboudian; D. R. Anderson

    1990-01-01

    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

  1. Plant response to environmental conditions: assessing potential production, water demand, and negative effects of water deficit

    PubMed Central

    Tardieu, François

    2013-01-01

    This paper reviews methods for analyzing plant performance and its genetic variability under a range of environmental conditions. Biomass accumulation is linked every day to available light in the photosynthetically active radiation (PAR) domain, multiplied by the proportion of light intercepted by plants and by the radiation use efficiency. Total biomass is cumulated over the duration of the considered phase (e.g., plant cycle or vegetative phase). These durations are essentially constant for a given genotype provided that time is corrected for temperature (thermal time). Several ways of expressing thermal time are reviewed. Two alternative equations are presented, based either on the effect of transpiration, or on yield components. Their comparative interests and drawbacks are discussed. The genetic variability of each term of considered equations affects yield under water deficit, via mechanisms at different scales of plant organization and time. The effect of any physiological mechanism on yield of stressed plants acts via one of these terms, although the link is not always straightforward. Finally, I propose practical ways to compare the productivity of genotypes in field environments, and a “minimum dataset” of environmental data and traits that should be recorded for that. PMID:23423357

  2. Belowground Water Dynamics Under Contrasting Annual and Perennial Plant Communities in an Agriculturally-Dominated Landscape

    NASA Astrophysics Data System (ADS)

    Mora, G.; Asbjornsen, H.; Helmers, M. J.; Shepherd, G. W.

    2005-12-01

    The conversion from grasslands and forests to row-crops in the Midwest has affected soil water cycling because plant characteristics are one of the main parameters determining soil storage capacity, infiltration rates, and surface runoff. Little is known, however, about the extent of modification of soil water dynamics under different plant communities. To address this important issue, we are documenting soil water dynamics under contrasting perennial and annual plant communities in an agriculturally-dominated landscape. Measurements of soil moisture and depths of uptake of source water were obtained for six vegetative cover types (corn and soybean field, brome pasture, degraded savanna, restored savanna, and restored prairie) at the Neal Smith National Wildlife Refuge in Prairie City, Iowa. The depths of uptake of soil water were determined on the basis of oxygen isotope composition of soil water and stem water. Measurements were performed once a month during an entire growing season. Preliminary results indicate that soil water present under the different vegetation types show similar profiles with depth during the dry months. Soil water in the upper 5 cm is enriched in oxygen-18 by about 5 per mil relative to soil water at 100 cm. Our preliminary results also indicate that the isotopic composition of stem water from annual plants is typically higher by about 2 per mil relative to that of stem water from perennial plants during the dry period. Whereas the oxygen isotopic composition for corn stem water is -5.49 per mil, that for elm and oak stem water is -7.62 and -7.51 per mil, respectively. The higher isotope values for corn suggest that annual crop plants are withdrawing water from shallower soil horizons relative to perennial plants. Moreover, our preliminary data suggest lower moisture content in soil under annual plant cover. We propose that the presence of deeper roots in the perennial vegetation allows these plants to tap into deeper water sources when soil moisture is low at shallow depths.

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

    PubMed

    Teerarak, Montinee; Laosinwattana, Chamroon; Charoenying, Patchanee

    2010-07-01

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

  4. Ozone decomposition.

    PubMed

    Batakliev, Todor; Georgiev, Vladimir; Anachkov, Metody; Rakovsky, Slavcho; Zaikov, Gennadi E

    2014-06-01

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

  5. Ozone decomposition

    PubMed Central

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

    2014-01-01

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

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

    PubMed Central

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

    2014-01-01

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

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

    SciTech Connect

    Bohac, C.E.

    1990-04-01

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

  8. Oxygen plants for coal gasification: Experience at the Cool Water GCC (gasification combined cycle) Power Plant: Final report

    SciTech Connect

    Petras, R.A.; Mostello, R.A.; Ko, A.P.

    1987-09-01

    This report presents the results of a study conducted by Airco-BOC for EPRI to assess performance of the Cool Water Oxygen Plant as it relates to the Cool Water Coal Gasification Program's requirements and evaluate alternate supply arrangements for future larger gasifier based combined cycle power plants. The Cool Water Oxygen Plant is the first application of a dedicated oxygen plant to a commercial sized gasifier based combined cycle power generating facility. Performance of the installation has exceeded the requirements of the Cool Water Program. Performance of the entire oxygen facility is presented at various loadings. Operating ranges of system components are discussed. The oxygen plant back-up system is described and subsequent performance noted. Load following tests were conducted by Airco-BOC and the Cool Water Program to determine the entire facility's operating flexibility. Operating ramp rates achievable on the oxygen plant have exceeded the requirements of the coal gasification facility. The oxygen plant's load-following system is described and results of load-following tests conducted are presented. A supplemental study was conducted to determine alternative oxygen generating facilities to support a nominal 600 MW Texaco gasifier based combined cycle power generation facility. The results of this section of the study are presented. 8 refs., 33 figs., 10 tabs.

  9. [Purification effects of large-area planting water hyacinth on water environment of Zhushan Bay, Lake Taihu].

    PubMed

    Liu, Guo-feng; Zhang, Zhi-yong; Yan, Shao-hua; Zhang, Ying-ying; Liu, Hai-qin; Fan, Cheng-xin

    2011-05-01

    Using water hyacinth and other fast-growing and high biomass of floating plants to purify polluted water has become an efficient and effective ecological restoration method at present. Effects of nutrients adsorption and water purification of planting water hyacinth on water quality in Zhushan Bay were studied. The results indicated that no anoxia was observed in water hyacinth planting areas because of wave disturbance and strong water exchange. Concentrations of TN and TP in water hyacinth planting areas were higher than that in the outside of stocking area (the content ranged 3.03-7.45 mg/L and 0.15-0.38 mg/L, respectively), and the content changes ranged 3.37-8.02 mg/L and 0.15-0.36 mg/L,respectively. The higher concentration of TN and TP in water indicated the water body was heavily polluted. Water hyacinth roots have a strong ability to adsorb suspended solids and algae cells, the concentration of Chl-a in stocking areas was higher than that in stocking fringe and outside, the maximum Chlorophyll in the stocking region in August was 177.01 mg/m3, and at the same time the concentrations in planting fringe and outside were 101.53 mg/m3 and 76.96 mg/m, respectively. Higher Chl-a content on water hyacinth roots indicated that water hyacinth had strong blocking effects on algae cells, and demonstrated it had a great purification effects on eutrophicated water, and it also provides a basis for the larger polluted water bodies purification in using water hyacinth. PMID:21780583

  10. Short Communication Differential decomposition of arbuscular mycorrhizal fungal hyphae and glomalin

    Microsoft Academic Search

    Peter D. Steinberg; Matthias C. Rillig

    Arbuscular mycorrhizal fungi (AMF) are obligate symbionts of most higher plants. In addition to being a major component of soil microbial biomass, AMF hyphae produce glomalin, a recalcitrant glycoproteinaceous substance highly correlated with soil aggregate water stability. This study addresses the lack of knowledge concerning the decomposition of hyphae and glomalin. We used an experimental design that exploited the lack

  11. Coupled Oxygen and Hydrogen Isotope Analysis of Water Along the Soil-Plant- Atmosphere Continuum

    NASA Astrophysics Data System (ADS)

    Huang, Z.; Webb, E. A.; Longstaffe, F. J.

    2008-12-01

    The oxygen and hydrogen isotope compositions of water within a plant vary with transpiration rates and the isotopic composition of soil water. Both of these parameters are affected by temperature and relative humidity. A controlled-temperature, growth-chamber experiment was conducted to determine the relationships among temperature, relative humidity, soil water evaporation and plant-water isotope composition in cattails and horsetails. Typha, a cattail species that grows in wetland conditions, and Equisetum, a horsetail species that prefers dry soils, were each grown in four chambers at 15, 20, 25 and 30 degrees Celsius. The oxygen and hydrogen isotope compositions of watering water, soil water, vapour in the growth chambers and plant water from the leaves and stems were analyzed throughout the eight-month long artificial growing season. Although the oxygen isotope composition of the watering water remained constant, the soil water, atmospheric vapour and plant water were progressively enriched in oxygen-18 and deuterium in each of the four chambers from low to high temperatures as a result of increasing evaporation. The oxygen isotope composition of plant water along the length of a single stem or leaf was increasingly enriched in the heavier isotopes towards the apex. There was no significant difference in the magnitude of this trend between species. These results indicate that the isotopic composition of plant water is primarily controlled by environmental conditions. The oxygen isotope composition of the water vapour in the growing chamber increased with temperature, consistent with equilibration between the vapour and the oxygen-18 enriched soil and plant water reservoirs. The magnitude and interaction of these variables, as measured for these modern samples of cattails and horsetails, should be useful in calibrating paleoclimate proxies based on fossilized plant materials (e.g., cellulose, phytoliths).

  12. Decomposition techniques

    USGS Publications Warehouse

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

    1992-01-01

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

  13. [Pilot-scale study on riparian mixed plant zones treating polluted river water].

    PubMed

    Li, Rui-hua; Guan, Yun-tao; He, Miao; Hu, Hong-yin; Jiang, Zhan-peng

    2006-04-01

    The polluted river water is treated with pilot-scale riparian zones of no aquatic plant, Vetiveria zizanioides + submerged plants, and weed+ Typha angustifolia L. + Phragmites communis. It is shown that the vegetation water zones are better than the no vegetation water zone and Vetiveria zizanioides + submerged plants zone is the best in improving water quality. The average removals of the Vetiveria zizanioides + submerged plant zone is 43.5% COD, 71.1% ammonia and 69.3% total phosphorus respectively. The dissolved oxygen (DO) and temperature of effluents from the three water zones are also investigated. It shows that DO of effluent from the vegetation zones are more stable than that of effluent from the no vegetation zone, and the temperature of the effluent from the vegetation zones are lower than that from the no vegetation zones. The submerged plants have special role in water quality improvement, and should be studied further. PMID:16767981

  14. Dioecy Impacts on Plant Water Fluxes in Riparian Ecosystems

    NASA Astrophysics Data System (ADS)

    Hultine, K. R.; Bush, S. E.; West, A. G.; Ehleringer, J. R.

    2005-12-01

    Dioecious plants are frequently associated with different spatial distributions of the two sexes across resource gradients. Segregation between sexes might be expected to occur if the cost of reproduction is greater in females than in males. If so, females would be under stronger selection to increase rates of resource uptake. Acer negundo is a dioecious riparian tree species that show spatial segregation among sexes: females are typically more common along streamside (high resource) environments than males. The spatial segregation of the sexes leads to the hypothesis that male and female individuals have varying influence on ecohydrological processes. To address this, we measured sap flux, water relations and hydraulic architecture of mature streamside (less than 1 m from stream channel) male and female Acer negundo trees occurring near Salt Lake City, Utah, USA during the 2004 growing season. Despite similar predawn and midday leaf water potentials, sap flux density ( Js) was 40 percent higher in female trees than in male trees during the 2004 growing season (n = 42 days, F = 73.56, P < 0.0001). Both genders showed a similar relationship between conducting sapwood area to stem diameter ratio suggesting that differences in Js scale to the whole tree level. Sap flux data from Acer negundo trees was compared to five other co-occurring riparian tree species. Female Acer negundo trees showed the highest Js among all species while Js in male Acer negundo trees was lower than all other species except one ( Acer grandidentatum). These data demonstrate that individual female Acer negundo trees have the capacity remove water at higher rates than males in high resource environments. The spatial segregation of the sexes along streamside environments may therefore have profound impacts on ecohydrological processes such as stream discharge, groundwater recharge, and nutrient cycling.

  15. Membrane integrity — direct turbidity measurement of filtrate from MF membrane modules at an operating potable water treatment plant

    Microsoft Academic Search

    James Naismith

    2005-01-01

    The San Patricio Municipal Water District is a wholesale supplier of water to cities and industry in south Texas, USA, with nine municipal and six major industrial customers. It operates three water treatment plants. The newest, Plant “C”, is an MF plant rated at 7.8 mgd using Pall\\/Asahi PVDF membrane modules. The plant has been in continuous operation since January

  16. Comprehensive cooling water study annual report. Volume V: wetland plant communities, Savannah River Plant

    SciTech Connect

    Gladden, J.B.; Lower, M.W.; Mackey, H.E.; Specht, W.L.; Wilde, E.W.

    1985-07-01

    Wetlands cover approximately 4% of the entire Savannah River watershed. The SRP contains 15,885 ha of wetlands of which 12,722 ha are bottomland hardwood and cypress-tupelo forest, predominantly along streams and in the Savannah River floodplain. The most obvious effect of cooling water releases on wetland plant communities is canopy loss by wetland tree species. About 770 ha of wetland tree canopy exhibits degree of alteration as a result of cooling water releases. Canopy loss continues at a rate of 10.5 to 11 ha/yr in river swamp areas associated with streams that currently receive reactor effluents (Pen Branch and Four Mile Creek). Closed canopy forest is replaced by a mixture of algal mat, thermally tolerant herbaceous, and scrub-shrub communities in the thermal streams and deltas. Following cessation of reactor effluent discharges, stream and delta areas are recolonized by a variety of herbaceous and scrub-shrub species, including many species that occur in the thermal deltas. Successional processes in the post-thermal areas result in a shift from herb dominated to shrub dominated communities. Limited data on primary production indicate that community biomass production rates recover to predistribution levels much faster than community structural parameters. Bald cypress trees in the nonthermal swamp areas do not appear to be replacing themselves, while water tupelo appears to be experiencing adequate regeneration. 65 refs., 52 figs., 45 tabs.

  17. Evaluation of coal-gasification - combustion-turbine power plants emphasizing low water consumption

    SciTech Connect

    Cavazo, R.; Clemmer, A.B.; de la Mora, J.A.; Grisso, J.R.; Klumpe, H.W.; Meissner, R.E.; Musso, A.; Roszkowski, T.R.

    1982-01-01

    A cost and performance study was made of several integrated power plants using coal gasification technology now in advanced development and combustion turbines for power generation. The principal emphasis was placed on studying plants using air cooling and comparing costs and performance of those plants with water-cooled coal gasification-combined-cycle (GCC) and conventional coal-fired power plants. The major objective was to determine whether cost and performance penalties would be prohibitive for air-cooled plants that use yet-to-be-developed coal gasifiers and commercially available combustion turbines for topping cycle power. The results indicate the following: air-cooled GCC plants using conceptual designs of either the Texaco or the British Gas Corporation (BGC) slaging gasifier could have coal-to-net electric power efficiencies equivalent to that of a water-cooled conventional coal-fired plant; the air-cooled GCC plants could produce electricity at busbar cost 1 to 3 mills per kWh (1980 dollars) less than busbar cost in a water-cooled conventional plant and only up to 2 mills per kWh higher than busbar cost in a water-cooled Texaco GCC plant; and even a simple-cycle regenerative combustion turbine plant fueled with gas from the BGC gasifier could have a coal-to-net electric power efficiency of over 30% and a busbar cost competitive with that in a water cooled conventional plant. The principal reason that air-cooled power plants using combustion turbines could be competitive with conventional water-cooled, coal-fired steam plants is that a majority of net power is produced by the combustion turbines, which require no cooling water. This, in turn, leads to a reduced cost and performance penalty when bottoming steam-cycle condensers are air-cooled.

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

    PubMed

    Stillwell, Ashlynn S; Webber, Michael E

    2014-04-15

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

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  20. Using Impinging Stream to Kill Algae, Fungi and Bacteria in Cooling Water of Thermal Power Plants

    Microsoft Academic Search

    Xia Yang; Jia Guo; Yu-xin Zhou; Yuan Wu; Hong-qiang Zhang; Lin Zhang

    2011-01-01

    The growth of living organism like algae, fungi and bacteria in the cooling-water system of thermal power plants may cause biological fouling. In this paper, a novel method using impinging stream was proposed to kill algae, fungi and bacteria in cooling water of thermal power plants. Using yeast cells as an example, the method of yeast cell disruption by a

  1. Soil and plant water relations in a crested wheatgrass pasture: response to spring grazing by cattle

    Microsoft Academic Search

    J. M. Wraith; D. A. Johnson; R. J. Hanks; D. V. Sisson

    1987-01-01

    Few field studies have attempted to relate effects of actual livestock grazing on soil and plant water status. The present study was initiated to determine the effects of periodic defoliations by cattle during spring on soil moisture and plant water status in a crested wheatgrass (Agropyron cristatum (L.) Gaertn. and A. desertorum (Fisch. ex Link) Schult.) pasture in central Utah.

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

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

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

  3. Estimating plant available water for general crop simulations in ALMANAC/APEX/EPIC/SWAT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Process-based simulation models ALMANAC/APEX/EPIC/SWAT contain generalized plant growth subroutines to predict biomass and crop yield. Environmental constraints typically restrict plant growth and yield. Water stress is often an important limiting factor; it is calculated as the sum of water use f...

  4. International Association for Ecology Partitioning of Water Resources among Plants of a Lowland Tropical Forest

    E-print Network

    Holbrook, N. Michele

    International Association for Ecology Partitioning of Water Resources among Plants of a Lowland of a lowland tropical forest Received: 9 May 1994 / Accepted: 26 August 1994 Abstract Source water used by plants of several species in a semi-evergreen lowland tropical forest on Barro Colorado Island, Panama

  5. The Diffusion of Biological Waste-Water Treatment Plants in the Dutch Food and Beverage Industry

    Microsoft Academic Search

    René Kemp

    1998-01-01

    This article develops an economic model of environmental technology adoption decisions. The model is applied econometrically to the diffusion of biological waste-water treatment plants in the Dutch food and beverage industry. It shows that it is possible to explain the overall diffusion pattern of biological waste-water treatment plants in terms of a rational choice model in which prospective adopters trade

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

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

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

  7. Water use in four model tropical plant associations established in the lowlands of Costa Rica

    Microsoft Academic Search

    Marco V. Gutiérrez-Soto; John J. Ewel

    2008-01-01

    We examined soil water use patterns of four model plant associations established in the North Caribbean lowlands of Costa Rica by comparing the stable hydrogen isotope composition, ?D, in xylem sap and in soil water at different depths, under rainy and dry conditions. Four 5-year-old model plant associations composed of 2 tree species (Hyeronima alchorneoides and Cedrela odorata) having different

  8. Influence of water solubility of granular zinc fertilizers on plant uptake and growth

    Microsoft Academic Search

    M. Amrani; D. G. Westfall; G. A. Peterson

    1999-01-01

    Zinc (Zn) fertilizer application has increased during the past three decades. This increase has created the need for more information regarding the availability and agronomic effectiveness of Zn containing fertilizers because differences of opinions exist relating the relationships between Zn water solubility and plant availability. Plant availability of eight commercialized Zn fertilizer materials having different water solubilities was measured under

  9. Ground performance of air conditioning and water recycle system for a space plant box

    NASA Astrophysics Data System (ADS)

    Tani, A.; Okuma, T.; Goto, E.; Kitaya, Y.; Saito, T.; Takahashi, H.

    Researchers from 5 Japanese universities have developed a plant growth facility (Space Plant Box) for seed to seed experiments under microgravity. The breadboard model of the Space Plant Box was fabricated by assembling subsystems developed for microgravity. The subsystems include air conditioning and water recycle system, air circulation system, water and nutrient delivery system, lighting system and plant monitoring system. The air conditioning and water recycle system is simply composed of a single heat exchanger, two fans and hydrophilic fibrous strings. The strings allow water movement from the cooler fin in the Cooling Box to root supporting materials in the Plant Growth Chamber driven by water potential deficit. Relative humidity in the Plant Growth Chamber can be changed over a wide range by controlling the ratio of latent heat exchange to sensible heat exchange on the cooling fin of the heat exchanger. The transpiration rate was successfully measured by circulating air inside the Plant Growth Chamber only. Most water was recycled and a small amount of water needed to be added from the outside. The simple, air conditioning and water recycle system for the Space Plant Box showed good performance through a barley ( Hordeum vulgare L.) growth experiment.

  10. Sap flow in the stem of water stressed soybean and maize plants

    Microsoft Academic Search

    Y. Cohen; M. G. Huck; J. D. Hesketh; J. R. Frederick

    1990-01-01

    Water stress was imposed upon soybean [Glyxine max (L.) Merr. cv. Williams] and maize [Zea mays (L.) cv. Pioneer 3377] plants grown under controlled-environment conditions during a growing period of several irrigation cycles. Transpiration rates of individual plants were measured with a calibrated heat-pulse method and correlated to the rate of water loss obtained from successive weighings of the pots

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

    PubMed Central

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

    2014-01-01

    Understanding water uptake and transport through the soil-plant continuum is vital for ecosystem management and agricultural water use. Plant water uptake under natural conditions is a non-steady transient flow controlled by root distribution, plant configuration, soil hydraulics, and climatic conditions. Despite significant progress in model development, a mechanistic description of transient water uptake has not been developed or remains incomplete. Here, based on advanced electrical network theory (RLC circuit theory), we developed a non-steady state biophysical model to mechanistically analyze the fluctuations of uptake rates in response to water stress. We found that the non-steady-state model captures the nature of instantaneity and hysteresis of plant water uptake due to the considerations of water storage in plant xylem and coarse roots (capacitance effect), hydraulic architecture of leaf system (inductance effect), and soil-root contact (fuse effect). The model provides insights into the important role of plant configuration and hydraulic heterogeneity in helping plants survive an adverse environment. Our tests against field data suggest that the non-steady-state model has great potential for being used to interpret the smart water strategy of plants, which is intrinsically determined by stem size, leaf size/thickness and distribution, root system architecture, and the ratio of fine-to-coarse root lengths. PMID:25335512

  12. A series RCL circuit theory for analyzing non-steady-state water uptake of maize plants.

    PubMed

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

    2014-01-01

    Understanding water uptake and transport through the soil-plant continuum is vital for ecosystem management and agricultural water use. Plant water uptake under natural conditions is a non-steady transient flow controlled by root distribution, plant configuration, soil hydraulics, and climatic conditions. Despite significant progress in model development, a mechanistic description of transient water uptake has not been developed or remains incomplete. Here, based on advanced electrical network theory (RLC circuit theory), we developed a non-steady state biophysical model to mechanistically analyze the fluctuations of uptake rates in response to water stress. We found that the non-steady-state model captures the nature of instantaneity and hysteresis of plant water uptake due to the considerations of water storage in plant xylem and coarse roots (capacitance effect), hydraulic architecture of leaf system (inductance effect), and soil-root contact (fuse effect). The model provides insights into the important role of plant configuration and hydraulic heterogeneity in helping plants survive an adverse environment. Our tests against field data suggest that the non-steady-state model has great potential for being used to interpret the smart water strategy of plants, which is intrinsically determined by stem size, leaf size/thickness and distribution, root system architecture, and the ratio of fine-to-coarse root lengths. PMID:25335512

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

    PubMed Central

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

    2014-01-01

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

  14. Chlorophyll fluorescence as an indicator of plant water status in cotton

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Various methods exist for the measurement of plant water status. Plant breeders value methods that are fast and inexpensive lending themselves to the efficient evaluation of large segregating populations. Chlorophyll fluorescence is a parameter commonly measured by plant physiologists when studying ...

  15. PEM water electrolysers: evidence for membrane failure in 100kW demonstration plants

    Microsoft Academic Search

    S. Stucki; G. G. Scherer; S. Schlagowski; E. Fischer

    1998-01-01

    The long term behaviour of two 100kW proton exchange membrane (PEM) water electrolyser plants is analysed. The systems had to be shut down due to problems with excessive levels of hydrogen in the oxygen product stream. The time to breakdown was different by a factor of nearly 10 from plant to plant. Post mortem analysis of the cell stacks revealed

  16. Model-Free Based Water Level Control for Hydroelectric Power Plants

    E-print Network

    Paris-Sud XI, Université de

    Model-Free Based Water Level Control for Hydroelectric Power Plants Cédric JOIN Gérard ROBERT for hydroelectric run-of-the river power plants. To modulate power generation, a level trajectory is planned, the set-point is followed even in severe operating conditions. Keywords: Hydroelectric power plants

  17. Carbohydrate partitioning in relation to whole plant production and water use of Vigna unguiculata (L.) Walp

    Microsoft Academic Search

    E. D. Schulze; K. Schilling; S. Nagarajah

    1983-01-01

    Increases in plant biomass are mainly a balance between growth of new leaves and growth of new roots, the new leaves having positive feedback upon the production process and the new roots having positive feedback upon the plant water status. Control of both opposing processes with respect to biomass production may be considered optimal whenever biomass of the plant reaches

  18. Research on Steam Generator Water Level Control System Based on Nuclear Power Plant Simulator

    Microsoft Academic Search

    Jianghua Guo

    \\u000a Steam generator (SG) is one of the most important equipments in nuclear power plants. The water level of SG must be kept in\\u000a a certain range to ensure the plants operate safely, reliably and economically. Nowadays, most SG water levels are controlled\\u000a by PID in PWR plants. In this paper, the mathematical models of SG level control system are built

  19. Plant viruses in aqueous environment - survival, water mediated transmission and detection.

    PubMed

    Mehle, Nataša; Ravnikar, Maja

    2012-10-15

    The presence of plant viruses outside their plant host or insect vectors has not been studied intensively. This is due, in part, to the lack of effective detection methods that would enable their detection in difficult matrixes and in low titres, and support the search for unknown viruses. Recently, new and sensitive methods for detecting viruses have resulted in a deeper insight into plant virus movement through, and transmission between, plants. In this review, we have focused on plant viruses found in environmental waters and their detection. Infectious plant pathogenic viruses from at least 7 different genera have been found in aqueous environment. The majority of the plant pathogenic viruses so far recovered from environmental waters are very stable, they can infect plants via the roots without the aid of a vector and often have a wide host range. The release of such viruses from plants can lead to their dissemination in streams, lakes, and rivers, thereby ensuring the long-distance spread of viruses that otherwise, under natural conditions, would remain restricted to limited areas. The possible sources and survival of plant viruses in waters are therefore discussed. Due to the widespread use of hydroponic systems and intensive irrigation in horticulture, the review is focused on the possibility and importance of spreading viral infection by water, together with measures for preventing the spread of viruses. The development of new methods for detecting multiple plant viruses at the same time, like microarrays or new generation sequencing, will facilitate the monitoring of environmental waters and waters used for irrigation and in hydroponic systems. It is reasonable to expect that the list of plant viruses found in waters will thereby be expanded considerably. This will emphasize the need for further studies to determine the biological significance of water-mediated transport. PMID:22871317

  20. Foliar absorption of intercepted rainfall improves woody plant water status most during drought.

    PubMed

    Breshears, David D; McDowell, Nathan G; Goddard, Kelly L; Dayem, Katherine E; Martens, Scott N; Meyer, Clifton W; Brown, Karen M

    2008-01-01

    A large proportion of rainfall in dryland ecosystems is intercepted by plant foliage and is generally assumed to evaporate to the atmosphere or drip onto the soil surface without being absorbed. We demonstrate foliar absorption of intercepted rainfall in a widely distributed, continental dryland, woody-plant genus: Juniperus. We observed substantial improvement in plant water status, exceeding 1.0 MPa water potential for drought-stressed plants, following precipitation on an experimental plot that excluded soil water infiltration. Experiments that wetted shoots with unlabeled and with isotopically labeled water confirmed that water potential responded substantially to foliar wetting, that these responses were not attributable to re-equilibration with other portions of the xylem, and that magnitude of response increased with water stress. Foliar absorption is not included in most ecological, hydrological, and atmospheric models; has implications for interpreting plant isotopic signatures; and not only supplements water acquisition associated with increases in soil moisture that follow large or repeated precipitation events, but also enables plants to bypass soil water uptake and benefit from the majority of precipitation events, which wet foliage but do not increase soil moisture substantially. Foliar absorption of intercepted water could be more important than previously appreciated, especially during drought when water stress is greatest. PMID:18376545

  1. Aquaporin structure-function relationships: water flow through plant living cells.

    PubMed

    Zhao, Chang-Xing; Shao, Hong-Bo; Chu, Li-Ye

    2008-04-01

    Plant aquaporins play an important role in water uptake and movement-an aquaporin that opens and closes a gate that regulates water movement in and out of cells. Some plant aquaporins also play an important role in response to water stress. Since their discovery, advancing knowledge of their structures and properties led to an understanding of the basic features of the water transport mechanism and increased illumination to water relations. Meanwhile, molecular and functional characterization of aquaporins has revealed the significance of their regulation in response to the adverse environments such as salinity and drought. This paper reviews the structure, species diversity, physiology function, regulation of plant aquaporins, and the relations between environmental factors and plant aquaporins. Complete understanding of aquaporin function and regulation is to integrate those mechanisms in time and space and to well regulate the permeation of water across biological membranes under changing environmental and developmental conditions. PMID:18063350

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

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

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

  3. [Effects of large-area planting water hyacinth on macro-benthos community structure and biomass].

    PubMed

    Liu, Guo-Feng; Liu, Hai-Qin; Zhang, Zhi-Yong; Zhang, Ying-Ying; Yan, Shao-Hua; Zhong, Ji-Cheng; Fan, Cheng-Xin

    2010-12-01

    The effects on macro-benthos and benthos environment of planting 200 hm2 water hyacinth (E. crassipens) in Zhushan Bay, Lake Taihu, were studied during 8-10 months consecutive surveys. Results indicated that average densities of mollusca (the main species were Bellamya aeruginosa) in far-planting, near-planting and planting area were 276.67, 371.11 and 440.00 ind/m2, respectively, and biomass were 373.15, 486.57 and 672.54 g/m2, respectively, showed that average density and biomass of planting area's were higher than those of others. However, the average density and biomass of Oligochaeta (the main species was Limodrilus hoffmeisteri) and Chironomidae in planting area were lower than that of outside planting area. The density and biomass of three dominant species of benthic animal increased quickly during 8-9 months, decreased quickly in October inside and outside water hyacinth planting area. The reason of this phenomenon could be possible that lots of cyanobacteria cells died and consumed dissolve oxygen in proceed decomposing. Algae cells released lots of phosphorus and nitrogen simultaneously, so macro-benthos died in this environment. The indexes of Shannon-Weaver and Simpson indicated that water environment was in moderate polluted state. On the basis of the survey results, the large-area and high-density planting water hyacinth haven't demonstrated a great impact on macrobenthos and benthos environment in short planting time (about 6 months planting time). PMID:21360881

  4. Host Response to Osmotic Stresses: Stomatal Behaviour and Water Use Efficiency of Arbuscular Mycorrhizal Plants

    Microsoft Academic Search

    Juan Manuel Ruiz-Lozano; Ricardo Aroca

    \\u000a Arbuscular mycorrhizal (AM) symbiosis can protect the host plants against the detrimental effects of the water deficit caused\\u000a by osmotic stresses such as drought and salinity. Stomatal conductance (gs) and water use efficiency (WUE) are among the most studied water relations parameters in the mycorrhizal literature, since\\u000a they are considered critical to the long-term performance of host plants in semiarid

  5. Solute accumulation in leaves and roots of woody plants subjected to water stress

    Microsoft Academic Search

    O. Osonubi; W. J. Davies

    1978-01-01

    Young seedlings of English Oak, Quercus robur L., and Silver Birch, Betula verrucosa Ehrl., were subjected to a number of consecutive periods during which water was withheld. During one 14-day period leaf-and soil-water potentials and leaf- and root-solute potentials of two groups of plants were sampled at noon of each day. One group of plants was watered every day while

  6. Plant hydraulic lift of soil water – implications for crop production and land restoration

    Microsoft Academic Search

    Hans-Holger Liste; Jason C. White

    2008-01-01

    Water more than other factors limits growth and productivity of terrestrial plants. Strategies of plants to cope with soil\\u000a drought include hydraulic redistribution of water via roots from moist to dry soil. During periods of drought, water may be\\u000a transported upward through root systems from moister subsurface to dry surface soil by a process known as “hydraulic lift”\\u000a (HL). On

  7. Water resource partitioning, stem xylem hydraulic properties, and plant water use strategies in a seasonally dry riparian tropical rainforest.

    PubMed

    Drake, P L; Franks, P J

    2003-11-01

    This study investigated seasonal variation in the origin of water used by plants in a riparian tropical rainforest community and explored linkages between plant water source, plant xylem hydraulic conductivity and response to the onset of dry conditions. The study focused on five co-dominant canopy species, comprising three tree species ( Doryphora aromatica, Argyrodendron trifoliolatum, Castanospora alphandii) and two climbing palms ( Calamus australis and Calamus caryotoides). Stable isotope ratios of oxygen in water (delta(18)O) from soil, groundwater, stream water and plant xylem measured in the wet season and the subsequent dry season revealed water resource partitioning between species in the dry season. Measurement of stem-area-specific hydraulic conductivity ( K(S)) in the wet season and subsequent dry season showed a significant dry-season loss of K(S) in three of the five species ( Castanospora alphandii, Calamus australis and C. caryotoides) and a decrease in mean K(S) for all species. This loss of hydraulic conductivity was positively correlated with the difference between wet-season and dry-season midday leaf water potentials and with leaf carbon isotope discrimination, indicating that plants that were less susceptible to loss of conductivity had greater control over transpiration rate and were more water-use efficient. PMID:12883990

  8. Water conservation and reuse in poultry processing plant—A case study

    Microsoft Academic Search

    E. M. Matsumura; J. C. Mierzwa

    2008-01-01

    Water conservation and water reuse concepts in food industry are presented in this paper. The developed study was in poultry processing plant, which focused water reuse evaluation for only non-potable applications. Although potable water reuse is allowed in some countries and there are international regulations about this practice [Environmental Protection Agency (EPA). Guidelines for Water Reuse; 2004. http:\\/\\/www.epa.gov\\/nrmrl\\/pubs\\/625r04108\\/625r04108.htm], this issue

  9. Beyond hypoxia: occurrence and characteristics of black blooms due to the decomposition of the submerged plant Potamogeton crispus in a shallow lake.

    PubMed

    Shen, Qiushi; Zhou, Qilin; Shang, Jingge; Shao, Shiguang; Zhang, Lei; Fan, Chengxin

    2014-02-01

    Organic matter-induced black blooms (hypoxia and an offensive odor) are a serious ecosystem disasters that have occurred in some large eutrophic shallow lakes in China. In this study, we investigated two separate black blooms that were induced by Potamogeton crispus in Lake Taihu, China. The main physical and chemical characteristics, including color- and odor-related substances, of the black blooms were analyzed. The black blooms were characterized by low dissolved oxygen concentration (close to 0 mg/L), low oxidation-reduction potential, and relatively low pH of overlying water. Notably higher Fe2+ and sigmaS(2-) were found in the black-bloom waters than in waters not affected by black blooms. The black color of the water may be attributable to the high concentration of these elements, as black FeS was considered to be the main substance causing the black color of blooms in freshwater lakes. Volatile organic sulfur compounds, including dimethyl sulfide, dimethyl disulfide, and dimethyl trisulfide, were very abundant in the black-bloom waters. The massive anoxic degradation of dead Potamogeton crispus plants released dimethyl sulfide, dimethyl disulfide, and dimethyl trisulfide, which were the main odor-causing compounds in the black blooms. The black blooms also induced an increase in ammonium nitrogen and soluble reactive phosphorus levels in the overlying waters. This extreme phenomenon not only heavily influenced the original lake ecosystem but also greatly changed the cycling of Fe, S, and nutrients in the water column. PMID:25076519

  10. Diverting water at dams during construction of hydro plants

    Microsoft Academic Search

    Kneitz

    1991-01-01

    The Federal Energy Regulatory Commission (FERC) estimates that hydropower could contribute another 24,000 MW of electricity to the US power supply by building new plants at existing dams. (Conventional hydro currently contributes about 71,800 MW of electricity.) When installing a plant at an existing dam, it is often feasible to connect the plant to the existing outlet works of the

  11. Litter decomposition of a tropical understory species ( Ctenanthe lubbersiana) grown under ambient and elevated CO 2

    NASA Astrophysics Data System (ADS)

    Nussbaumer, U.; Ascher, J.; Kraft, A.; Insam, H.

    A CO 2 evolution and a dissolved organic carbon (DOC)-die-away test were used to determine the inherent decomposability of plant litter of Ctenanthe lubbersiana grown under ambient (340 ppm) and elevated CO 2 (610 ppm). The CO 2 evolution of leaf litter in a 10 day decomposition assay was retarded by 7% (P=0.046). In the DOC-die-away test, the decomposition of a leaf litter hot water extract was retarded by 8% (P=0.039). The decomposition of the solid litter fraction was retarded by 16% (P=0.101). The decomposition rate of petioles was not affected by elevated CO 2. Despite the differences were small, the results suggest possible effects on ecosystem C cycling.

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

    USGS Publications Warehouse

    Diehl, Timothy H.; Harris, Melissa A.

    2014-01-01

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

  13. Wheat streak mosaic: A classic case of plant disease impact on soil water content and crop water-use efficiency

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this article, we describe the relationship between wheat streak mosaic (WSM) severity and soil water content as a prime example of the effect of a plant disease on soil water status and its implications for irrigated agriculture. The present study was part of a larger investigation which included...

  14. Wheat Streak Mosaic: A classic case of plant disease impact on soil water content and crop water-use efficiency

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this article, we describe the relationship between wheat streak mosaic (WSM) severity and soil water content as a prime example of the effect of a plant disease on soil water status and its implications for irrigated agriculture. The present study was part of a larger investigation which included...

  15. Stomatal Responses to Water Stress and to Abscisic Acid in Phosphorus-Deficient Cotton Plants

    PubMed Central

    Radin, John W.

    1984-01-01

    Cotton (Gossypium hirsutum L.) plants were grown in sand culture on nutrient solution containing adequate or growth-limiting levels of P. When water was withheld from the pots, stomata of the most recently expanded leaf closed at leaf water potentials of approximately ?16 and ?12 bars in the normal and P-deficient plants, respectively. Pressure-volume curves showed that the stomata of P-deficient plants closed when there was still significant turgor in the leaf mesophyll. Leaves of P-deficient plants accumulated more abscisic acid (ABA) in response to water stress, but the difference was evident only at low water potentials, after initiation of stomatal closure. In leaves excised from unstressed plants, P deficiency greatly increased stomatal response to ABA applied through the transpiration stream. Kinetin blocked most of this increase in apparent sensitivity to ABA. The effect of P nutrition on stomatal behavior may be related to alterations of the balance between ABA and cytokinins. PMID:16663851

  16. Stomatal responses to water stress and to abscisic Acid in phosphorus-deficient cotton plants.

    PubMed

    Radin, J W

    1984-10-01

    Cotton (Gossypium hirsutum L.) plants were grown in sand culture on nutrient solution containing adequate or growth-limiting levels of P. When water was withheld from the pots, stomata of the most recently expanded leaf closed at leaf water potentials of approximately -16 and -12 bars in the normal and P-deficient plants, respectively. Pressure-volume curves showed that the stomata of P-deficient plants closed when there was still significant turgor in the leaf mesophyll. Leaves of P-deficient plants accumulated more abscisic acid (ABA) in response to water stress, but the difference was evident only at low water potentials, after initiation of stomatal closure. In leaves excised from unstressed plants, P deficiency greatly increased stomatal response to ABA applied through the transpiration stream. Kinetin blocked most of this increase in apparent sensitivity to ABA. The effect of P nutrition on stomatal behavior may be related to alterations of the balance between ABA and cytokinins. PMID:16663851

  17. Water impacts of CO2 emission performance standards for fossil fuel-fired power plants.

    PubMed

    Talati, Shuchi; Zhai, Haibo; Morgan, M Granger

    2014-10-21

    We employ an integrated systems modeling tool to assess the water impacts of the new source performance standards recently proposed by the U.S. Environmental Protection Agency for limiting CO2 emissions from coal- and gas-fired power plants. The implementation of amine-based carbon capture and storage (CCS) for 40% CO2 capture to meet the current proposal will increase plant water use by roughly 30% in supercritical pulverized coal-fired power plants. The specific amount of added water use varies with power plant and CCS designs. More stringent emission standards than the current proposal would require CO2 emission reductions for natural gas combined-cycle (NGCC) plants via CCS, which would also increase plant water use. When examined over a range of possible future emission standards from 1100 to 300 lb CO2/MWh gross, new baseload NGCC plants consume roughly 60-70% less water than coal-fired plants. A series of adaptation approaches to secure low-carbon energy production and improve the electric power industry's water management in the face of future policy constraints are discussed both quantitatively and qualitatively. PMID:25229670

  18. DESCRIPTION OF THE FRESH AND SALT WATER SUPPLY AND PUMPING PLANTS USED FOR THE AQUARIUM.

    E-print Network

    DESCRIPTION OF THE FRESH AND SALT WATER SUPPLY AND PUMPING PLANTS USED FOR THE AQUARIUM. BY I. S. K was supplied from one of the water mains under the aquarium building at an average pressure of about 60 pounds per square inch, and before passing into the supply pipes erected over the aquarium this water

  19. Hydrogeophysical Monitoring of Water Uptake in Root Zones of Small Plants

    Microsoft Academic Search

    S. Al Hagrey; U. Werban; R. Meissner; A. Ismaeil; W. Rabbel

    2005-01-01

    We have monitored the water content in root zones in hydrogeophysical experiments and studied daily and seasonal variations of water uptake. Plants grew in plastic pots filled with fine sand. The surface of the pots was isolated to minimize evaporation, i.e., most water is consumed for transpiration. We installed geoelectric surface and subsurface profiles (electrode interval = 1.5 cm), and

  20. Effects of greywater irrigation on plant growth, water use and soil properties

    Microsoft Academic Search

    U. Pinto; B. L. Maheshwari; H. S. Grewal

    2010-01-01

    Glasshouse experiments were conducted to examine the effects of greywater irrigation on the growth of silverbeet plants, their water use and changes in soil properties. The experimental treatments included in the study were: irrigating with 100% potable water (control, treatment T0), irrigating with 100% greywater (treatment T1), irrigating with a mixture of greywater and potable water in 1:1 ratio (treatment

  1. Infield monitoring of cleaning efficiency in waste water treatment plants using two phenol-sensitive biosensors

    Microsoft Academic Search

    Catalin Nistor; Andreas Rose; Marinella Farré; Leonard Stoica; Ulla Wollenberger; Tautgirdas Ruzgas; Dorothea Pfeiffer; Damià Barceló; Lo Gorton; Jenny Emnéus

    2002-01-01

    Two amperometric biosensors based on the enzymes cellobiose dehydrogenase (CDH) and quinoprotein-dependent glucose dehydrogenase (GDH), have been applied for monitoring the phenolic content in water samples, collected at different stages of a waste water treatment process, thus representing different cleaning levels of two waste water treatment plants (WWTPs). The biosensor measurements were performed in-field, compared with the results obtained by

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

    ERIC Educational Resources Information Center

    Domenghini, Jacob Cody

    2012-01-01

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

  3. Computers and Chemical Engineering 26 (2002) 5979 Energy efficient water utilization systems in process plants

    E-print Network

    Savelski, Mariano J.

    2002-01-01

    Computers and Chemical Engineering 26 (2002) 59­79 Energy efficient water utilization systems. Once the energy and water targets have been identified, an MILP model is generated. This model, which. Keywords: Water utilization networks; Process plants; Energy minimization; Wastewater minimization

  4. Assessment of cooling water supply in the United States. [Thermal power plants

    Microsoft Academic Search

    D. E. Peterson; J. C. Jr. Sonnichsen

    1977-01-01

    Consistent with the Water Pollution Act of 1965 the Clear Water Restoration Act of 1966, and the Federal Water Pollution Act Amendment of 1972, and realizing the importance of long-range planning, studies were performed to examine the effect of the legislation on the methods of waste management for thermal power plants. Streams in eight major drainage areas in the United

  5. Advanced Power Plant Modeling with Applications to an Advanced Boiling Water

    E-print Network

    Mitchell, John E.

    Advanced Power Plant Modeling with Applications to an Advanced Boiling Water Reactor and a Heat and an Advanced Boiling Water Reactor (ABWR). The continuity wave equa- tions for single and two-phase flow advanced method, are shown. These both are applied to a simplified model of the Advanced Boil- ing Water

  6. Implementation of small water power plants regarding future virtual power plants

    Microsoft Academic Search

    S. Stepanescu; C. Rehtanz; S. Arad; I. Fotau; M. Marcu; F. Popescu

    2011-01-01

    The paper studies the possibilities to implement small hydro power plants in a valley from Romania using hydrographical data. These power plants are combined to form a virtual power plant. The purpose is the study of the behavior of the distribution grid in a consideration of virtual power plant concept. The loading and the voltage of the lines are the

  7. Water temperature differences by plant community and location in re-established wetlands in the Sacramento-San Joaquin Delta, California, July 2005 to February 2008

    USGS Publications Warehouse

    Crepeau, Kathryn L.; Miller, Robin L.

    2014-01-01

    Rates of carbon storage in wetlands are determined by the balance of its inputs and losses, both of which are affected by environmental factors such as water temperature and depth. In the autumn of 1997, the U.S. Geological Survey re-established two wetlands with different shallow water depths—about 25 and 55 centimeters deep—to investigate the potential to reverse subsidence of delta islands by preserving and accumulating organic substrates derived from plant biomass inputs over time. Because cooler water temperatures can slow decomposition rates and increase accretion of plant biomass, water temperature was recorded from July 2005 to February 2008 in the deeper of the two wetlands, where areas of emergent and submerged vegetation persisted throughout the study, to assess differences in water temperature between the two vegetation types. Water temperature was compared at three depths in the water column between areas of emergent and submerged vegetation and between areas near the water inflow and in the wetland interior in both vegetation types. The latter comparison was a way of evaluating the effect of the length of time water had resided in the wetland on water temperatures. There were statistically significant differences in water temperature at all depths between the two vegetation types. Overall, in areas of emergent marsh vegetation, the mean water temperature at the surface was 1.4 degrees Celsius (°C) less than it was in areas of submerged vegetation; however, when analyses accounted for the changes in temperature due to seasonal and diurnal cycles, differences in the mean water temperature between the vegetation types were even greater than this. For example, in the spring, the mean temperatures in areas of emergent marsh vegetation at the surface, mid-point, and near the sediment in the water column were 2.0, 2.3, and 2.1 °C less, respectively, than water temperatures in areas of submerged vegetation. When diurnal changes in temperature were accounted for by comparing temperatures in mid-afternoon (at 3 p.m.), water-temperature differences were even greater than the seasonal means indicated. In areas of emergent vegetation, the mean temperatures were cooler than temperatures in areas of submerged vegetation at the surface, the mid-point, and near the sediment in the water column by 3.9, 3.6, and 2.3 °C, respectively. Furthermore, from July 2005 through December 2006, water temperatures at the surface in the interior of the wetland were significantly cooler than in areas near the inflow supplying water from the San Joaquin River by 1.0 °C in areas of submerged vegetation and by 1.1 °C in areas of emergent vegetation.

  8. [Interference of allelopathic rice cultivars on barnyardgrass under different water irrigation and rice plant density].

    PubMed

    Xu, Zhenghao; He, Yong; Wang, Yiping; Yu, Gusong

    2004-09-01

    Pot culture experiments were conducted to examine the effects of water irrigation and rice plant density on the interference of allelopathic rice on barnyardgrass (Echinochloa crus-galli). The results showed that under water irrigations, allelopathic rice cultivars Xiayitiao, Gumei 2 and Zhong 156 significantly reduced the plant height of barnyardgrass than non-allelopathic rice cultivars Xiushui 63 and Chunjiang 11. Barnyardgrass plants grew shorter as rice plant density increased. Allelopathic rice cultivars Jizaoxian and Gumei 2 interfered with barnyardgrass, even at their densities as low as 4 plants per pot, and the interference reduced plant height of barnyardgrass significantly compared with the non-rice control. Allelopathic rice cultivars Xiayitiao, Jizaoxian, PI312777, TN1, Gumei 2 and Zhong 156 at 32 rice plants per pot inhibited the growth of barnyardgrass significantly than Chunjiang 11. PMID:15669488

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

    PubMed Central

    2013-01-01

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

  10. Summary Plant tissues shrink and swell in response to changes in water pressure. These strains can be easily mea-

    E-print Network

    Podgornik, Rudolf

    Summary Plant tissues shrink and swell in response to changes in water pressure. These strains can be easily mea- sured, e.g., at the surface of tree stems, to obtain indirect infor- mation about plant water factor. Introduction Water inside terrestrial plants is generally in a state of tension, i.e., negative

  11. Transpiration, Water Absorption, and Internal Water Balance of Cotton Plants as Affected by Light and Changes in Saturation Deficit 1

    PubMed Central

    Ehrler, W. L.; van Bavel, C. H. M.; Nakayama, F. S.

    1966-01-01

    In controlled environment studies of cotton plants (Gossypium barbadense L.) a light-induced acceleration of transpiration upset the water balance established in the dark because of a lag in water absorption. A plant-water deficit could be generated either by sudden illumination at a given saturation deficit (sd) of the air, or by raising the sd in conjunction with illumination, without different effects. Direct water balance measurements were confirmed in every experiment by beta ray gauge detection of changes in leaf-water content resulting from unequal gain and loss of water by the whole plant. Recovery from the initial loss of turgidity always was faster and more complete at the higher than at the lower values of sd. Recovery occurred even in the light at the higher values of sd, but was enhanced by return to darkness and a lower sd, which at times resulted in superhydration. Rehydration in the light could be attributed to at least 2 processes: A) a diminished transpiration rate if earlier water loss was sufficient to induce stomatal closure, and B) an increased rate of water absorption. The data suggest that a water deficit, temporary or persisting, does not cause a significantly lowered transpiration rate; thus, recovery must depend on increased absorption. The communicative link between the 2 processes appears weak, transmitting strong signals only. PMID:16656235

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

    PubMed

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

    2010-01-01

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

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

    PubMed

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

    2008-09-01

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

  14. Generalized water-table and water-level data at the US Air Force plant 42 and vicinity, Palmdale, California, March-April, 1997

    USGS Publications Warehouse

    Christensen, Allen H.

    1999-01-01

    The U.S. Air Force Plant 42 (Plant 42) which is in the Antelope Valley about 1.5 miles northeast of Palmdale and 3 miles southeast of Lancaster in Los Angeles County. Historically, ground water has been the primary source of water owing, in large part, to the scarcity of surface water in the region. Since 1972, supplemental surface water has been imported from the California Water Project to help meet the demand for water. Despite the importation of surface water, ground-water withdrawal for both municipal and agricultural uses is affecting ground-water levels in the vicinity of Plant 42. To better understand the effects of ground-water withdrawal on ground-water levels and movement in the area, the U.S. Geological Survey (USGS), in cooperation with the U.S. Air Force, constructed a generalized water-table-contour map of the aquifer system underlying Plant 42 and the surrounding area.

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

    PubMed

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

    2004-12-01

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

  16. Hydroxyl radical formation during methane oxidation and water decomposition on Pt measured by laser-induced fluorescence

    SciTech Connect

    Mooney, C.E.; Anderson, L.C.; Lunsford, J.H. (Texas A and M Univ., College Station (United States))

    1991-08-08

    The hydroxyl radical is one of the most important radicals involved in catalyzed chemical reaction and combustion processes. Laser-induced fluorescence (LIF) was used to monitor the formation and desorption of OH{sup {sm bullet}} radicals over a Pt wire during the catalyzed oxidation of methane. As in the pt-catalyzed oxidation of hydrogen, the apparent activation energy of OH{sup {sm bullet}} desorption, E{sub a}, depends strongly on the fuel-to-oxygen ratio, varying from {approximately}33 kcal/mol at high O{sub 2}/CHH{sub 4} values to {approximately}56 kcal/mol at low O{sub 2}/CH{sub 4} ratios. The reaction of surface oxygen with D{sub 2} during the decomposition of H{sub 2}O on Pt shows that the surface oxygen concentration influences E{sub a} for OH{sup {sm bullet}} desorption on platinum.

  17. A laser-induced fluorescence study of OH desorption from Pt(111) during oxidation of hydrogen in O2 and decomposition of water

    NASA Astrophysics Data System (ADS)

    Fridell, Erik; Elg, Alf-Peter; Rosén, Arne; Kasemo, Bengt

    1995-04-01

    The desorption of OH radicals from Pt(111) at high temperature, ?1000 K, during the water formation (H2+1/2 O2?H2O) and water decomposition reactions, respectively, was investigated using the laser-induced fluorescence technique. The results are compared with corresponding data from our laboratory for polycrystalline Pt. The OH desorption rate in H2+O2 at 1-100 mTorr total pressure has its maximum at 8%-9% relative H2 concentration for surface temperatures between 1100 and 1400 K. With H2 replaced by D2, the OD desorption rate maximizes at somewhat higher relative hydrogen content. The apparent activation energy for OH desorption increases from about 1.4 eV at low relative hydrogen concentration to about 2.0 eV at hydrogen contents of 25% or more. For the water decomposition reaction, the apparent activation energy for OH desorption was found to be 1.7±0.2 eV at 0.5 Torr and 1.9±0.2 eV at 1 Torr. These differences in apparent activation energies are primarily due to kinetic effects. The results are analyzed within a kinetic model previously developed by Hellsing et al. [J. Catal. 132, 210 (1991)], and are also compared with previous data for polycrystalline Pt. The kinetic model calculations give good overall agreement with the measured OH desorption rates as functions of temperature, H2/O2 mixture and H2O pressure, respectively. A nonuniqueness problem, with respect to the choice of kinetic parameters, is encountered in the simulation of the measured data; quite different sets of two of the kinetic constants, namely the activation energy for water formation (via OH+H?H2O) and the activation energy for OH desorption can reproduce the data as long as their difference is constant. This nonuniqueness problem, which is a consequence of the steady-state nature of the measurements, is analyzed and discussed in some detail, as are some apparent contradictions in the absolute values of reported kinetic constants in the literature. From this analysis two important conclusions are drawn. (i) The apparent contradictions in the literature about absolute values of activation energies for the water formation reaction and for OH-desorption may be less severe than believed or nonexistent. (ii) Coverage dependent activation energies must be considered and experimental exploration of such coverage dependencies are needed to create a firmer base for the kinetic modeling of the H2/O2 reaction on Pt.

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

    PubMed Central

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

    2015-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2007-12-01

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

  20. Decomposition in northern Minnesota peatlands

    SciTech Connect

    Farrish, K.W.

    1985-01-01

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

  1. Plant and water-level dynamics in an east texas shrub\\/hardwood bottomland wetland

    Microsoft Academic Search

    Milton W. Weller

    1989-01-01

    Plant distribution and layering were analyzed from four line transects across aninehectare shrub swamp and adjacent hardwood\\u000a bottomlands, and water fluctuations and hydroperiod were assessed via six wells and staff gauges. Vegetational transition\\u000a from deep to shallow water was buttonbushCephalanthus occidentalis, water elmPlanera aquatica, overcup oakQuercus lyrata, water oakQ. nigra, willow oakQ. phellos, and several other hardwoods intermixed at less

  2. Plant water use in a greenhouse: theory and measurements 

    E-print Network

    Shaer, Yacoub Adib

    1981-01-01

    related to plant height, explaining the effect of plant growth on evapotranspiration. Hanan (1972) also reported a strong positive correlation of EI' with radiation inside the greenhouse. Lake et al. (1966) found that the proportion of solar radiation.... . . . . . . . . . . . , . . . . . Input Data Sets. . . . . . . . , . . . . . . . . , . . . . . . . . . . . Correction of the Dew Cell Data. . . . . . . . Calculation of Infiltration Rate. . . . . . . Modification of the SG79 Model. Calculation of Sky Radiation...

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

    NASA Astrophysics Data System (ADS)

    Debaere, P.

    2014-12-01

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

  4. New coal plant technologies will demand more water

    SciTech Connect

    Peltier, R.; Shuster, E.; McNemar, A.; Stiegel, G.J.; Murphy, J.

    2008-04-15

    Population shifts, growing electricity demand, and greater competition for water resources have heightened interest in the link between energy and water. The US Energy Information Administration projects a 22% increase in US installed generating capacity by 2030. Of the 259 GE of new capacity expected to have come on-line by then, more than 192 GW will be thermoelectric and thus require some water for cooling. Our challenge will become balancing people's needs for power and for water. 1 ref., 7 figs.

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

    SciTech Connect

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

    1991-01-01

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

  6. Ozonation at the 900 cfs Los Angeles Water Purification Plant

    Microsoft Academic Search

    Paul W. Prendiville

    1986-01-01

    In 1979. the California Safe Drinking Water Act established a new turbidity limit of 0.5 turbidity unit for drinking waters. To meet this new standard at the Owens River Aqueductplantin Los Angelesi aprocessinvolvingpreozonation and direct filtration was tested and selected. In addition to providing water which meets the required turbidity standard, the ozone process reduces THM levels by about 50%,

  7. Put mycorrhizae to use: The natural fungi can greatly improve plants’ nutrient and water uptake

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mycorrhizal fungi are beneficial root-inhabiting organisms that can increase nutrient and water uptake by plants and decrease disease susceptibility. Inoculum of mycorrhizal fungi is commercially available; however, the theoretical benefits of inoculation during nursery production are sometimes not ...

  8. Ultrasound acoustic emission in water-stressed plants of Picea abies Karst.

    E-print Network

    Paris-Sud XI, Université de

    Ultrasound acoustic emission in water-stressed plants of Picea abies Karst. M. Borghetti1 A. Raschi acoustic emissions from the stems of potted saplings of Picea abies Karst. during the summer, relating

  9. Water Treatment Plant Sludges--An Update of the State of the Art: Part 2.

    ERIC Educational Resources Information Center

    American Water Works Association Journal, 1978

    1978-01-01

    This report outlines the state of the art with respect to nonmechanical and mechanical methods of dewatering water treatment plant sludge, ultimate solids disposal, and research and development needs. (CS)

  10. Water/Wastewater Treatment Plant Field Device Wiring Method Decision Analysis

    E-print Network

    Dicus, Scott C.

    2011-12-16

    The choice of field device wiring method for water and wastewater treatment plant design is extremely complex and contains many variables. The choice not only affects short-term startup and equipment costs, but also ...

  11. COMETABOLISM OF TRIHALOMETHANES BY NITRIFYING BIOFILTERS UNDER DRINKING WATER TREATMENT PLANT CONDITIONS

    EPA Science Inventory

    EPA Identifier: FP916412 Title: Cometabolism of Trihalomethanes by Nitrifying Biofilters Under Drinking Water Treatment Plant Conditions Fellow (Principal Investigator): David G. Wahman Institution: University of Texas at Austin EPA ...

  12. Electrophysiological assessment of water stress in fruit-bearing woody plants.

    PubMed

    Ríos-Rojas, Liliana; Tapia, Franco; Gurovich, Luis A

    2014-06-15

    Development and evaluation of a real-time plant water stress sensor, based on the electrophysiological behavior of fruit-bearing woody plants is presented. Continuous electric potentials are measured in tree trunks for different irrigation schedules, inducing variable water stress conditions; results are discussed in relation to soil water content and micro-atmospheric evaporative demand, determined continuously by conventional sensors, correlating this information with tree electric potential measurements. Systematic and differentiable patterns of electric potentials for water-stressed and no-stressed trees in 2 fruit species are presented. Early detection and recovery dynamics of water stress conditions can also be monitored with these electrophysiology sensors, which enable continuous and non-destructive measurements for efficient irrigation scheduling throughout the year. The experiment is developed under controlled conditions, in Faraday cages located at a greenhouse area, both in Persea americana and Prunus domestica plants. Soil moisture evolution is controlled using capacitance sensors and solar radiation, temperature, relative humidity, wind intensity and direction are continuously registered with accurate weather sensors, in a micro-agrometeorological automatic station located at the experimental site. The electrophysiological sensor has two stainless steel electrodes (measuring/reference), inserted on the stem; a high precision Keithley 2701 digital multimeter is used to measure plant electrical signals; an algorithm written in MatLab(®), allows correlating the signal to environmental variables. An electric cyclic behavior is observed (circadian cycle) in the experimental plants. For non-irrigated plants, the electrical signal shows a time positive slope and then, a negative slope after restarting irrigation throughout a rather extended recovery process, before reaching a stable electrical signal with zero slope. Well-watered plants presented a continuous signal with daily maximum and a minimum EP of similar magnitude in time, with zero slope. This plant electrical behavior is proposed for the development of a sensor measuring real-time plant water status. PMID:24877671

  13. COOLING WATER ISSUES AND OPPORTUNITIES AT U.S. NUCLEAR POWER PLANTS

    SciTech Connect

    Gary Vine

    2010-12-01

    This report has been prepared for the Department of Energy, Office of Nuclear Energy (DOE-NE), for the purpose of providing a status report on the challenges and opportunities facing the U.S. commercial nuclear energy industry in the area of plant cooling water supply. The report was prompted in part by recent Second Circuit and Supreme Court decisions regarding cooling water system designs at existing thermo-electric power generating facilities in the U.S. (primarily fossil and nuclear plants). At issue in the courts have been Environmental Protection Agency regulations that define what constitutes “Best Technology Available” for intake structures that withdraw cooling water that is used to transfer and reject heat from the plant’s steam turbine via cooling water systems, while minimizing environmental impacts on aquatic life in nearby water bodies used to supply that cooling water. The report was also prompted by a growing recognition that cooling water availability and societal use conflicts are emerging as strategic energy and environmental issues, and that research and development (R&D) solutions to emerging water shortage issues are needed. In particular, cooling water availability is an important consideration in siting decisions for new nuclear power plants, and is an under-acknowledged issue in evaluating the pros and cons of retrofitting cooling towers at existing nuclear plants. Because of the significant ongoing research on water issues already being performed by industry, the national laboratories and other entities, this report relies heavily on ongoing work. In particular, this report has relied on collaboration with the Electric Power Research Institute (EPRI), including its recent work in the area of EPA regulations governing intake structures in thermoelectric cooling water systems.

  14. Applications of convex optimization in plant-wide control of Membrane Distillation BioReactor (MDBR) water recycling plant

    Microsoft Academic Search

    Avinash Vijay; Keck Voon Ling; Anthony Gordon Fane

    2010-01-01

    The objective is to develop a control system that will enable the Membrane Distillation Bio-Reactor (MDBR) water recycling plant to become self sufficient and fully automatic. In order to ensure continuous operation, the control system must maintain conditions required for the micro-organisms to survive. These requirements need to be met even when solar radiation and weather conditions are not conducive

  15. 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...

  16. 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...

  17. Influence of temperature and process technology on the occurrence of Aeromonas species and hygienic indicator organisms in drinking water production plants.

    PubMed

    Kersters, I; Van Vooren, L; Huys, G; Janssen, P; Kersters, K; Verstraet, W

    1995-09-01

    The occurrence of Aeromonas spp. and hygienic indicator organisms in raw and treated waters of five drinking water production plants in Flanders (Belgium) was surveyed over a period of 17 months. Aeromonads were isolated on ampicillin-dextrin agar (ADA) and further identified by gas-liquid chromatographic analysis of their cellular fatty acid methyl ester (FAME) content. ADA medium was found to be highly specific for the enumeration of Aeromonas spp. In general, Aeromonas counts were very low in untreated groundwater but numbered 10(4)-10(6) colony-forming units per liter in open storage reservoirs for surface water. Aeromonas spp. were seasonally distributed with maximal densities occurring during the summer. The ecology of Aeromonas in the different waters was studied in relation to the physical, chemical, and microbiological water characteristics. Strongly positive correlations were observed between Aeromonas densities and heterotrophic plate counts, whereas a clearly negative relationship was found with dissolved oxygen. On average, 99.7% of the aeromonads were removed by flocculation-decantation followed by breakpoint chlorination, whereas 98.9% were removed by slow sand filtration. Flocculation-decantation without breakpoint chlorination did not reduce the microbial numbers. At three of four drinking water production plants tested, rapid sand filtration decreased the number of aeromonads and hygienic indicator organisms. At one plant, however, the numbers of Aeromonas and hygienic indicator organisms were high in the sand filter effluents. Increased numbers of aeromonads were also counted in the effluent of the activated carbon filters. Hence, inactivation of Aeromonas spp. by the current process technology appears not sufficient to exclude postchlorination. The survival of aeromonads in certain filter systems may be due to the growth of these bacteria on biodegradable organic material, provided by the decomposition from bacteria, algae, or other sources. PMID:24185486

  18. Dynamic modelling of waste-water treatment plants based on Lemna gibba

    Microsoft Academic Search

    G. Vatta; R. Rota; N. Boniardi; G. Nano

    1995-01-01

    In this paper, a comprehensive process model able to simulate the behaviour of a waste-water treatment plant based on Lemna gibba has been developed. This model accounts for the main chemical and biochemical phenomena involved in a natural waste-water treatment system. Several comparisons with experimental data obtained both in mini-ponds and in realsize plants have confirmed the reliability of the

  19. Industrial extraction pilot plant for stripping H 2S gas from Black Sea water

    Microsoft Academic Search

    S. A. Naman; I. Engin Ture; T. Nejat Veziroglu

    2008-01-01

    The results from the laboratory-scale extraction pilot plant unit for the separation of H2S from Black Sea water lead us to build a novel industrial extraction pilot plant to concentrate H2S from 10ppm to above 10000ppm. The processing of 109m3 of water containing 10ppm will produce 0.833tons of hydrogen and therefore a technology for extraction and concentration of H2S is

  20. The influence of water level and salinity on plant assemblages of a seasonally flooded Mediterranean wetland

    Microsoft Academic Search

    S. C. L. Watt; E. García-Berthou; L. Vilar

    2007-01-01

    We studied the key environmental variables shaping plant assemblages in Mediterranean abandoned ricefields with contrasting\\u000a freshwater inputs over saline sediments. Plant species cover, water levels and soil variables were studied following a stratified\\u000a random sampling design. Multivariate analysis identified water regime, particularly summer and autumn irrigation, as the most\\u000a important environmental variable associated with vegetation composition. Distribution of annual and

  1. Improvement of water treatment pilot plant with Moringa oleifera extract as flocculant agent

    Microsoft Academic Search

    2009-01-01

    Moringa oleifera extract is a high?capacity flocculant agent for turbidity removal in surface water treatment. A complete study of a pilot?plant installation has been carried out. Because of flocculent sedimentability of treated water, a residual turbidity occured in the pilot plant (around 30 NTU), which could not be reduced just by a coagulation?flocculation?sedimentation process. Because of this limitation, the pilot

  2. Total energy concept at the joint water pollution control plant. [Carson, CA

    Microsoft Academic Search

    G. M. Adams; J. D. Eppich; W. E. Garrison; J. C. Gratteau

    1980-01-01

    The proposed total-energy facilities at the Joint Water Pollution Control Plant (Carson, Calif.) are designed to maximize electrical power production to meet significant increases in demands resulting from secondary treatment, and to minimize dependence on public utilities for natural gas and water by reusing waste heat and plant effluent. The generator prime-mover selection process includes analyses of reciprocating engines, simple-cycle

  3. Review: mechanisms for boron deficiency-mediated changes in plant water relations.

    PubMed

    Wimmer, Monika A; Eichert, Thomas

    2013-04-01

    Boron (B) is an essential microelement for plants and is constantly needed throughout the plant life due to its function as a structural element of the plant cell wall. B deficiency is a wide-spread problem in agricultural areas world-wide, and management of B nutrition is challenged by sudden occurrences of B deficiency or inconsistent effects of foliar B application. The effects of insufficient B supply on different structures relevant for the plant water status have been heavily researched, but the resulting conclusions are contradictory and no clear picture has so far emerged that fully explains the inconsistencies. B deficiency can affect water uptake by inhibition of root and shoot growth and by upregulation of water channels. Structural damage to xylem vessels can limit water transport to arial plant parts, while water loss can be altered by impaired barrier functions of leaf surfaces and reduced photosynthesis. In consequence of all these effects, transpiration is reduced in B-deficient plants under well-watered conditions. Under drought conditions, the responsiveness of stomata is impaired. Possible consequences of damaged vasculature for plant B nutrition include the reduced effectiveness of foliar B fertilization, especially in species with high B phloem mobility. Changes in leaf surface properties can further reduce B uptake after foliar application. In species with low B phloem mobility, weakened xylem vessels may not be able to supply sufficient B to arial parts under conditions of increased B demand, such as during bud development of trees. Since structural damage to vessels is hardly reversible, these effects could be permanent, even if B deficiency was only transient. Another consequence of reduced water status is the higher susceptibility of B-deficient plants to other abiotic stresses, which also impair water relations, especially drought. Since damage to vasculature can occur before visible symptoms of B deficiency appear in shoots, the importance to develop reliable diagnostic tools for detection of sub-acute B deficiency is highlighted. PMID:23415325

  4. A co-beneficial system using aquatic plants: bioethanol production from free-floating aquatic plants used for water purification.

    PubMed

    Soda, S; Mishima, D; Inoue, D; Ike, M

    2013-01-01

    A co-beneficial system using constructed wetlands (CWs) planted with aquatic plants is proposed for bioethanol production and nutrient removal from wastewater. The potential for bioethanol production from aquatic plant biomass was experimentally evaluated. Water hyacinth and water lettuce were selected because of their high growth rates and easy harvestability attributable to their free-floating vegetation form. The alkaline/oxidative pretreatment was selected for improving enzymatic hydrolysis of the aquatic plants. Ethanol was produced with yields of 0.14-0.17 g-ethanol/ g-biomass in a simultaneous saccharification and fermentation mode using a recombinant Escherichia coli strain or a typical yeast strain Saccharomyces cerevisiae. Subsequently, the combined benefits of the CWs planted with the aquatic plants for bioethanol production and nutrient removal were theoretically estimated. For treating domestic wastewater at 1,100 m(3)/d, it was inferred that the anoxic-oxic activated sludge process consumes energy at 3,200 MJ/d, whereas the conventional activated sludge process followed by the CW consumes only 1,800 MJ/d with ethanol production at 115 MJ/d. PMID:23752400

  5. Optimizing Cooling Tower Performance Refrigeration Systems, Chemical Plants, and Power Plants All Have A Resource Quietly Awaiting Exploitation-Cold Water!! 

    E-print Network

    Burger, R.

    1991-01-01

    OPTIMIZING COOLING TOWER PERFOnMANCE REFnIGERATION SYSTEMS, CHEMICAL PLANTS, AND POWER PLANTS ALL HAVE A RESOURCE QUIETLY AWAITING EXPLOITATION - COLD WATER!! ROBERT BURGER President Burger and Associates. Inc Dallas, Texas Cooling towers... 62 OPTIMIZING COOLING TOWER PERFOflMANCE REFflIGERATION SYSTEMS, CHEMICAL PLANTS, AND POWER PLANTS ALL HAVE A flESOURCE QUIETLY AWAITING EXPLOITATION COLD WATER!! ROBERT BURGER President Burger and Associates. DaBas, Texas Inc pretty well convinced...

  6. Pathogenicity to Ornamental Plants of Some Existing Species and New Taxa of Phytophthora from Irrigation Water

    Microsoft Academic Search

    Chuanxue Hong; Patricia A. Richardson; Ping Kong

    2008-01-01

    Hong, C., Richardson, P. A., and Kong, P. 2008. Pathogenicity to ornamental plants of some existing species and new taxa of Phytophthora from irrigation water. Plant Dis. 92:1201-1207. Eighteen isolates from 12 species of Phytophthora, including several new taxa, were tested for pathogenicity to six ornamental and four vegetable species. The following three inoculation methods were used depending on infection

  7. Investigation of an automatic control system of an atomic energy plant with boiling-water reactor

    Microsoft Academic Search

    V. I. Gritskov; V. A. Afanas'ev; G. A. Sankovskii; R. A. Shugam; I. N. Sokolov; Yu. A. Solov'ev

    1968-01-01

    Conclusions The experimental investigations of the dynamics of the atomic electric power plant with boiling water vessel reactor and natural circulation and automatic control system have shown that:-1)The pressure and level in the reactor, the level in the steam generators, and the preturbine pressure must be regarded as the main regulated parameters of the plant.2)When changes are made in the

  8. The determination of boron in soil extracts, plant materials, composts, manures, water and nutrient solutions

    Microsoft Academic Search

    Benjamin Wolf

    1971-01-01

    A rapid colorimetric method for the determination of boron in soil extracts, plant materials, composts, manures, water and nutrient solution is proposed. The method is rapid, reliable and carried out in aqueous solution. A marked advantage is that boron can be determined in the same soil extract or plant material digest used for determination of other elements.

  9. Method of water level control for a combined cycle power plant and control system therefor

    Microsoft Academic Search

    1982-01-01

    A method and system for controlling water level of a drum of a heat recovery steam generator for a combined cycle power plant is provided. The combined cycle power plant includes gas and steam turbines and the steam generator for recovering heat in exhaust gases from the gas turbine and for using the recovered heat to produce and supply steam

  10. GEOGRAPHIC VARIATION IN NUTRIENT AVAILABILITY, STOICHIOMETRY, AND METAL CONCENTRATIONS OF PLANTS AND PORE-WATER IN

    E-print Network

    Gotelli, Nicholas J.

    AND PORE-WATER IN OMBROTROPHIC BOGS IN NEW ENGLAND, USA Nicholas J. Gotelli1 , Paula J. Mouser2 , Stephen P of nutrient limitation and broad-scale anthropogenic inputs. In 24 rain-fed (ombrotrophic) peatland bogs of three common bog plant genera ­ leather leaf (Chamaedaphne calyculata), northern pitcher plant

  11. Optimal supervisory control of a central chilled water plant with heuristic search sequential quadratic programming

    Microsoft Academic Search

    Jian Sun

    2010-01-01

    A new methodology for adapting rigorous simulation programs to optimal supervisory control of a central chilled water plant is proposed in this article, which solves plant operation mode optimization and set points optimization by combining heuristic search with sequential quadratic programming. The mathematical basis of this algorithm is developed. A new derivative calculation strategy is introduced in set points optimization.

  12. Enterococcus faecalis Gene Transfer under Natural Conditions in Municipal Sewage Water Treatment Plants

    Microsoft Academic Search

    HERBERT MARCINEK; REINHARD WIRTH; ALBRECHT MUSCHOLL-SILBERHORN; MATTHIAS GAUER

    1998-01-01

    Received 2 October 1997\\/Accepted 12 November 1997 The ability of Enterococcus faecalis to transfer various genetic elements under natural conditions was tested in two municipal sewage water treatment plants. Experiments in activated sludge basins of the plants were performed in a microcosm which allowed us to work under sterile conditions; experiments in anoxic sludge digestors were performed in dialysis bags.

  13. Simulation in Aspen Plus of Power Plant's Circulating Water Waste Heat Recovery System

    Microsoft Academic Search

    Bi Qingsheng; Ma Yanliang; Bai Zhang

    2010-01-01

    Power Plant Circulating Water (PPCW) waste heat recycling is an important way of increasing a power plant's primary energy ratio. According to the PPCW waste heat regenerative thermal system, the authors propose two modes of heat pump heat regenerative of the system, ASPEN PLUS, one of the most famous softwares of chemical engineering,was used to stimulatethe process. The measures to

  14. Energy conservation and resource utilisation in waste-water treatment plants

    Microsoft Academic Search

    S. A. Tassou

    1988-01-01

    The operation of waste-water treatment plants is to a large extent energy-dependent. This paper examines the energy requirements of these plants and explores ways of conserving energy through electrical and thermal load management and resource recovery and utilisation. The gas produced during the process of anaerobic digestion can be used to drive packaged CHP systems for local heat and power

  15. Hepatitis A among workers from a waste water treatment plant during a small community outbreak

    Microsoft Academic Search

    G De Serres; D Laliberté

    1997-01-01

    OBJECTIVE: This is a case report describing the occurrence of hepatitis A in three workers at a waste water treatment plant during a small community outbreak involving 16 cases. CASE REPORT: The first case was a 26 year old operator who had worked in the plant for two years, the second was a 23 year old employee hired to add

  16. Effects of water pulsing on individual performance and competitive hierarchies in plants

    E-print Network

    Novoplansky, Ariel

    Effects of water pulsing on individual performance and competitive hierarchies in plants and there were significant hierarchies of competitive ability. Under frequent pulses, the fast-growing species plants and ability to tolerate the presence of neighbors. However, under infrequent pulses, the slowest

  17. Effect of plant uptake strategy on the water?optimal root depth

    Microsoft Academic Search

    A. J. Guswa

    2010-01-01

    The depth of plant roots depends on a variety of conditions, including soil properties, vegetation type, nutrient availability, and climate. A water-optimal root depth is determined by equating the marginal carbon cost of deeper roots with the benefit of those roots to continued transpiration. This work compares the effect of two bounding strategies of plant uptake, conservative and intensive, on

  18. Plant-Water Relations in Seasonally Dry Tropical Montane Cloud Forests

    E-print Network

    Goldsmith, Gregory Rubin

    2012-01-01

    role in determining plant survival-mortality dynamics in aavailability may alter plant survival-mortality dynamics andplant and soil water relations in and around a forest gap in West Africa during the dry season may influence seedling establishment and survival.

  19. Modeling plant-atmosphere carbon and water fluxes along a CO2 gradient

    Technology Transfer Automated Retrieval System (TEKTRAN)

    At short time scales (hourly to daily), plant photosynthesis and transpiration respond nonlinearly to atmospheric CO2 concentration and vapor pressure deficit, depending on plant water status and thus soil moisture. Modeling vegetation and soil responses to different values of CO2 at multiple time s...

  20. Plant responses, climate pivot points, and trade-offs in water-limited ecosystems

    USGS Publications Warehouse

    Munson, Seth M.

    2013-01-01

    Plant species in dryland ecosystems are limited by water availability and may be vulnerable to increases in aridity. Methods are needed to monitor and assess the rate of change in plant abundance and composition in relation to climate, understand the potential for degradation in dryland ecosystems, and forecast future changes in plant species assemblages. I employ nearly a century of vegetation monitoring data from three North American deserts to demonstrate an approach to determine plant species responses to climate and critical points over a range of climatic conditions at which plant species shift from increases to decreases in abundance (climate pivot points). I assess these metrics from a site to regional scale and highlight how these indicators of plant performance can be modified by the physical and biotic environment. For example, shrubs were more responsive to drought and high temperatures on shallow soils with limited capacity to store water and fine-textured soils with slow percolation rates, whereas perennial grasses were more responsive to precipitation in sparse shrublands than in relatively dense grasslands and shrublands, where competition for water is likely more intense. The responses and associated climate pivot points of plant species aligned with their lifespan and structural characteristics, and the relationship between responses and climate pivot points provides evidence of the trade-off between the capacity of a plant species to increase in abundance when water is available and its drought resistance.

  1. The role of aquaporins in cellular and whole plant water balance

    Microsoft Academic Search

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

    2000-01-01

    Aquaporins are water channel proteins belonging to the major intrinsic protein (MIP) superfamily of membrane proteins. More than 150 MIPs have been identified in organisms ranging from bacteria to animals and plants. In plants, aquaporins are present in the plasma membrane and in the vacuolar membrane where they are abundant constituents. Functional studies of aquaporins have hitherto mainly been performed

  2. Applying DDC and VFD to Central Chilled Water Plants for Profits 

    E-print Network

    Utesch, A. L.

    1985-01-01

    The Central Utility Plant (CUP) at D/FW Airport is a facility that was first placed in operation during the Fall of 1973 and has continuously operated since that time. The original plant produced steam for heating and for chilled water generation...

  3. ACCEPTED BY WATER ENVIRONMENT RESEARCH ODOR AND VOC REMOVAL FROM WASTEWATER TREATMENT PLANT

    E-print Network

    ACCEPTED BY WATER ENVIRONMENT RESEARCH _______ ODOR AND VOC REMOVAL FROM WASTEWATER TREATMENT PLANT of biofilters for sequential removal of H2S and VOCs from wastewater treatment plant waste air. The biofilter volatile organic compounds (VOCs) and toxic air pollutants emitted from wastewater and solids handling

  4. Cadmium movement and accumulation in a sediment-water-plant system. [Myriophyllum spicatum L

    Microsoft Academic Search

    Peverly

    1988-01-01

    Studies in 1986 of cadmium (Cd) mobilization from dosed pond sediments after inputs stopped in 1983 indicated that Cd may be absorbed by rooted aquatic plants and thus returned to the aquatic food chain. The limits of this process were studied in 1987. Cd in plants, water, and sediments was determined and characterized in replicated, outdoor aquaria after single acute

  5. Plant hormones regulate fast shoot elongation under water: From genes to communities

    Microsoft Academic Search

    L. A. C. J. Voesenek; J. H. G. M. Rijnders; A. J. M. Peeters; H. M. V. van de Steeg; J. C. J. M. de Kroon

    2004-01-01

    Flooding affects the abundance and distribution of plant species worldwide. Many plants are damaged or even killed by flooding events, due to the associated oxygen deprivation in cells. Stimulated shoot elongation is an important adaptive mode that can restore contact of leaves with the atmosphere above the water surface. This strongly improves inward diffusion of oxygen and the rate of

  6. Nitrogen limitation of microbial decomposition in a grassland under elevated CO2

    NASA Astrophysics Data System (ADS)

    Hu, S.; Chapin, F. S.; Firestone, M. K.; Field, C. B.; Chiariello, N. R.

    2001-01-01

    Carbon accumulation in the terrestrial biosphere could partially offset the effects of anthropogenic CO2 emissions on atmospheric CO 2 (refs 1, 2). The net impact of increased CO2 on the carbon balance of terrestrial ecosystems is unclear, however, because elevated CO2 effects on carbon input to soils and plant use of water and nutrients often have contrasting effects on microbial processes. Here we show suppression of microbial decomposition in an annual grassland after continuous exposure to increased CO2 for five growing seasons. The increased CO 2 enhanced plant nitrogen uptake, microbial biomass carbon, and available carbon for microbes. But it reduced available soil nitrogen, exacerbated nitrogen constraints on microbes, and reduced microbial respiration per unit biomass. These results indicate that increased CO2 can alter the interaction between plants and microbes in favour of plant utilization of nitrogen, thereby slowing microbial decomposition and increasing ecosystem carbon accumulation.

  7. Is water immersion useful for analyzing gravity resistance responses in terrestrial plants?

    PubMed

    Ooume, Kentaro; Soga, Kouichi; Wakabayashi, Kazuyuki; Hoson, Takayuki

    2004-11-01

    Water immersion has been used as a simulator of microgravity for analyzing gravity responses in semiaquatic plants such as rice. To examine whether or not water immersion for a short experimental period is a useful microgravity simulator even in terrestrial plants, we analyzed effects of water immersion on the cell wall rigidity and metabolisms of its constituents in azuki bean epicotyls. The cell wall rigidity of epicotyls grown underwater was significantly lower than that in the control. Water immersion also caused a decrease in molecular mass of xyloglucans as well as the thinning of the cell wall. Such changes in the mechanical and chemical properties of the cell wall underwater were similar to those observed in microgravity conditions in space. These results suggest that water immersion for a short period is a useful system for analyzing gravity resistance responses even in terrestrial plants. PMID:15858369

  8. Metal biomonitoring in water resources of Eastern Ghats, Koraput (Orissa), India by aquatic plants.

    PubMed

    Rai, U N; Sinha, S; Chandra, P

    1996-11-01

    Biomonitoring of toxic metals in the water resources used by indigenous tribal communities in Koraput district, Orissa, India was carried out under the National Technology Mission Project. Most of the water bodies catering for the day-to-day needs of the local inhabitants were found to contain high concentrations of Fe and Mn in addition to Cr, Cd, Pb and Cu. The water bodies supported by a great number of phytodiversity and the plants growing therein accumulated significantly high amounts of these toxic metals, submerged plants being more efficient than floating ones. The species like Chara corallina and Spirogyra spp. showed significant potential to magnify Cd and Pb in their tissue several times more than the concentrations in surrounding water. The levels of metals in the plants occurring at places where the metal content is very high could be used for indicating the status of water. PMID:24193821

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

    USGS Publications Warehouse

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

    1997-01-01

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

  10. No evidence of complementary water use along a plant species richness gradient in temperate experimental grasslands.

    PubMed

    Bachmann, Dörte; Gockele, Annette; Ravenek, Janneke M; Roscher, Christiane; Strecker, Tanja; Weigelt, Alexandra; Buchmann, Nina

    2015-01-01

    Niche complementarity in resource use has been proposed as a key mechanism to explain the positive effects of increasing plant species richness on ecosystem processes, in particular on primary productivity. Since hardly any information is available for niche complementarity in water use, we tested the effects of plant diversity on spatial and temporal complementarity in water uptake in experimental grasslands by using stable water isotopes. We hypothesized that water uptake from deeper soil depths increases in more diverse compared to low diverse plant species mixtures. We labeled soil water in 8 cm (with 18O) and 28 cm depth (with ²H) three times during the 2011 growing season in 40 temperate grassland communities of varying species richness (2, 4, 8 and 16 species) and functional group number and composition (legumes, grasses, tall herbs, small herbs). Stable isotope analyses of xylem and soil water allowed identifying the preferential depth of water uptake. Higher enrichment in 18O of xylem water than in ²H suggested that the main water uptake was in the upper soil layer. Furthermore, our results revealed no differences in root water uptake among communities with different species richness, different number of functional groups or with time. Thus, our results do not support the hypothesis of increased complementarity in water use in more diverse than in less diverse communities of temperate grassland species. PMID:25587998

  11. Self-generation of Control Rules Using Hierarchical and Nonhierarchical Clustering for Coagulant Control of Water Treatment Plants

    Microsoft Academic Search

    Hyeon Bae; Sungshin Kim; Yejin Kim; Chang-Won Kim

    2005-01-01

    \\u000a In coagulant control of water treatment plants, rule extraction, one of datamining categories, was performed for coagulant\\u000a control of a water treatment plant. Clustering methods were applied to extract control rules from data. These control rules\\u000a can be used for fully automation of water treatment plants instead of operator’s knowledge for plant control. In this study,\\u000a statistical indices were used

  12. Determination of arsenic species in water, soils and plants

    Microsoft Academic Search

    J. Mattusch; R. Wennrich; A.-C. Schmidt; W. Reisser

    2000-01-01

    Ion chromatographic separation coupled with ICP-MS was used to determine arsenic species in plant and soil extracts. A scheme\\u000a for growth, harvesting, sample pre-treatment and analysis was developed for the arsenic species to enable determination. Preliminary\\u000a results obtained with ten herb plants grown on arsenic-contaminated soil compared to non-contaminated soil show a heterogeneous\\u000a pattern of accumulation rate, metabolization and detoxification

  13. Watering converts a CAM plant to daytime CO2 uptake

    Microsoft Academic Search

    Terry L. Hartsock; Park S. Nobel

    1976-01-01

    THREE different photosynthetic options have been identified in plants1,2: (1) most plants have the reductive pentose phosphate or C3 pathway, where CO2 is incorporated into ribulose-1,5-diphosphate (RuDP) to yield two molecules of 3-phosphoglyceric acid, a three-carbon compound; (2) the C4 mode, where the first photosynthetic products are four-carbon dicarboxylic acids like oxaloacetate and malate formed following CO2 incorporation into phosphoenolpyruvate

  14. Modelling of coagulant dosage in a water treatment plant

    Microsoft Academic Search

    Claude Gagnon; Bernard P. A. Grandjean; Jules Thibault

    1997-01-01

    The coagulation-flocculation is a major step in the drinkable water treatment process allowing the removal of colloidal particles. The water treatment facilities of the City of Sainte-Foy have been well instrumented and process variables such as temperature, pH, turbidity, conductivity of raw and treated water along with actual coagulant dosage available have been measured and stored each 5 min for

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

    EPA Science Inventory

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

  16. Fast Approximate Convex Decomposition 

    E-print Network

    Ghosh, Mukulika

    2012-10-19

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

  17. Reflectance of vegetation, soil, and water. [effects of measurable plant parameters on multispectral signal variations

    NASA Technical Reports Server (NTRS)

    Wiegand, C. L. (principal investigator)

    1974-01-01

    The author has identified the following significant results. Reflectance of crop residues, that are important in reducing wind and water erosion, was more often different from bare soil in band 4 than in bands 5, 6, or 7. The plant parameters leaf area index, plant population, plant cover, and plant height explained 95.9 percent of the variation in band 7 (reflective infrared) digital counts for cotton and 78.2 percent of the variation in digital counts for the combined crops sorghum and corn; hence, measurable plant parameters explain most of the signal variation recorded for corpland. Leaf area index and plant population are both highly correlated with crop yields; since plant population can be readily measured (or possibly inferred from seeding rates), it is useful measurement for calibrating ERTS-type MSS digital data in terms of yield.

  18. Water use in four model tropical plant associations established in the lowlands of Costa Rica.

    PubMed

    Gutiérrez-Soto, Marco V; Ewel, John J

    2008-12-01

    We examined soil water use patterns of four model plant associations established in the North Caribbean lowlands of Costa Rica by comparing the stable hydrogen isotope composition, deltaD, in xylem sap and in soil water at different depths, under rainy and dry conditions. Four 5-year-old model plant associations composed of 2 tree species (Hyeronima alchorneoides and Cedrela odorata) having different architecture and phenology were studied. Average tree height was 8.9 and 7.6 m, respectively. Each tree species was grown in monoculture and in polyculture with 2 perennial monocotyledons (Euterpe oleracea and Heliconia imbricata). Maximum rooting depth at the time of 6D determination was approximately 2 m for almost all species. Most roots of all species were concentrated in the upper soil layers. Stomatal conductance to water vapor (gS) was higher in the deciduous C. odorata than in the evergreen H. alchorneoides; within each species, g, did not differ when the trees were grown in mono or in polyculture. During the rainy season, gradients in soil water 6D were not observed. Average rainy season xylem sap deltaD did not differ among members of the plant combinations tested (-30% per thousand), and was more similar to deltaD values of shallow soil water. Under dry conditions, volumetric soil water content declined from 50 to approximately 35%, and modest gradients in soil water deltaD were observed. Xylem sap deltaD obtained during dry conditions was significantly lower than rainy season values. Xylem sap deltaD of plants growing in the four associations varied between -9 and -22% per hundred, indicating that shallow water was predominantly absorbed during the dry period too. Differences in xylem sap deltaD of trees and monocots were also detected, but no significant patterns emerged. The results suggest that: (a) the plant associations examined extracted water predominantly from shallow soil layers (<1 m), (b) the natural isotopic variation in soil and plant water at the study site was low, and (c) the plant mixes obtain water from more than a single soil layer simultaneously. Temporal factors were important in determining the competition and complementary relations observed among the trees and the perennial monocots. Under the prevailing environmental conditions, water use in these plant associations was determined largely by species-specific attributes such as biomass allocation to fine roots, phenology, and canopy architecture, and to a lesser extent by water limitations. PMID:19419093

  19. PRODUCTION AND RELEASE OF PLANT MATERIAL IN BRACKISH AND FRESHWATER WETLANDS

    EPA Science Inventory

    Production, decomposition, and transport of detritus were investigated in the fresh-water and brackish water wetlands of the Altamaha River Delta, Georgia from April 17, 1978-April 1979. Maximum live standing crop biomass of Spartina cynosuroides, a brackish water marsh plant, wa...

  20. Monitoring of the water reservoir of the water-power-plant ``Zarnowiec'' applying RTK-GPS measurements preliminary results

    Microsoft Academic Search

    R. Szpunar; A. Pachuta; J. Walo; T. Olszak

    2003-01-01

    Control measurements of the Water-Power-Plant ``Zarnowiec'' applying GPS and terrestrial geodetic methods have been carried out since the half of nineties last century. Repeated measurements proved short-period variation of the position of control-points on the level of 2 cm resulting from the changes of the water-level in the reservoir. Such results have caused the authors to make attempts at periodical

  1. A MultiChannel Continuous Water Toxicity Monitoring System: Its Evaluation and Application to Water Discharged from a Power Plant

    Microsoft Academic Search

    Byoung Chan Kim; Man Bock Gu

    2005-01-01

    A multi-channel continuous water toxicity monitoring system was, after confirming the systems' performance, implemented to samples of water discharged from power plants to detect and classify their toxicity using several recombinant bioluminescent bacteria. Each channel of the system is composed of a series of two mini-bioreactors to enable a continuous operation, i.e., without system interruption due to highly toxic samples.

  2. Adaptive Neuro-Fuzzy Inference System PID controller for SG water level of nuclear power plant

    Microsoft Academic Search

    Xue-Kui Wang; Xu-Hong Yang; Gang Liu; Hong Qian

    2009-01-01

    In a nuclear power plant, the water level in the steam generator (SG) is one of main causes that shutdown the reactor, this problem has been of great concern for many years as the SG is a highly nonlinear system showing inverse response dynamics. For controlling the SG water level at a certain range, adaptive neuro-fuzzy inference system (ANFIS) PID

  3. Performance assessment for the water level control system in steam generator of the nuclear power plant

    Microsoft Academic Search

    Zhi Zhang; Lisheng Hu

    2011-01-01

    Steam generator water level control system is the most important components of the nuclear power plant. The operating steam generator water level controller is increasingly recognized as a capital asset that should be maintained and monitored routinely. However, this issue as the control loop performance assessment problem is still open. Considering this issue, a major contribution of this paper is

  4. Plant physiology Role of awns in ear water-use efficiency

    E-print Network

    Paris-Sud XI, Université de

    Plant physiology Role of awns in ear water-use efficiency and grain weight in barley J Bort net photosynthesis and water-use efficiency (WUE: net photosynthesis/transpiration) of ears and flag photosynthesis of awned ears was markedly higher than that of awnless ears, until 3 weeks after anthesis

  5. SEATTLE DISTRIBUTION SYSTEM CORROSION CONTROL STUDY. VOLUME 2. TOLT RIVER WATER PILOT PLANT STUDY

    EPA Science Inventory

    For 6 months, the Seattle Water Department conducted a corrosion treatment pilot plant study, obtaining data on the treatment of Tolt River water with lime/sodium carbonate, lime/sodium bicarbonate, and lime/bicarbonate/silicate. Continuous-flow pipe coupon tests were conducted t...

  6. Water Treatment Plant Operation. Volume II. A Field Study Training Program.

    ERIC Educational Resources Information Center

    California State Univ., Sacramento. School of Engineering.

    The purpose of this water treatment field study training program is to: (1) develop new qualified water treatment plant operators; (2) expand the abilities of existing operators, permitting better service both to employers and public; and (3) prepare operators for civil service and certification examinations (examinations administered by…

  7. Water Treatment Plant Operation Volume 2. A Field Study Training Program. Revised.

    ERIC Educational Resources Information Center

    California State Univ., Sacramento. School of Engineering.

    The purpose of this water treatment field study training program is to: (1) develop new qualified water treatment plant operators; (2) expand the abilities of existing operators, permitting better service both to employers and public; and (3) prepare operators for civil service and certification examinations (examinations administered by…

  8. Comprehensive Cooling Water Study: Volume 6, Federally endangered species, Savannah River Plant: Final report

    Microsoft Academic Search

    1987-01-01

    The Comprehensive Cooling Water Study (CCWS) was initiated in 1983 to evaluate the environmental effects of the intake and release of cooling water on the structure and function of aquatic ecosystems at the Savannah River Plant. The initial report described the results from the first year of the study. This document is the final report and concludes the program. The

  9. Hydro energy potential of cooling water at the thermal power plant

    Microsoft Academic Search

    Vladimir D. Stevanovic; Aleksandar Gajic; Ljubodrag Savic; Vladan Kuzmanovic; Dusan Arnautovic; Tina Dasic; Blazenka Maslovaric; Sanja Prica; Bojan Milovanovic

    2011-01-01

    The hydro energy of the gravity water flow from the coal-fired thermal power plant units to the river in an open cooling system of turbine condensers is determined. On the basis of statistical data for a long time period, the water net head duration curve due to the river annual level change, as well as the reduction of the hydro

  10. Water Treatment Plant Operation. Volume I. A Field Study Training Program.

    ERIC Educational Resources Information Center

    California State Univ., Sacramento. School of Engineering.

    The purpose of this water treatment field study training program is to: (1) develop new qualified water treatment plant operators; (2) expand the abilities of existing operators, permitting better service both to employers and public; and (3) prepare operators for civil service and certification examinations (examinations administered by…

  11. Existing reactor water plant study -- B, C, D, DR, F and H reactors interim report

    Microsoft Academic Search

    1959-01-01

    The five year forecast for operation of the HAPO reactors calls for the achievement of increased process water flows in B, C, D, DR, F and H reactors. The Process Design Operation has initiated a study in support of this forecast whose objectives are: to determine present water plant and effluent system flow capabilities; to provide basic data for determining

  12. Improving the efficiency of water use by plant breeding and molecular biology

    Microsoft Academic Search

    R. A. Richards; C. López-Castañeda; H. Gomez-Macpherson; A. G. Condon

    1993-01-01

    Plant breeding over the last century has indirectly increased water use efficiency of the major grain crops because yield has increased with no additional water use. These increases have been substantial in all major food crops. Improved varieties have come from conventional breeding programs where selection has been for yield. Although these increases are likely to continue, they may not

  13. PACKAGE PLANTS: A COST-EFFECTIVE SOLUTION TO SMALL WATER SYSTEM TREATMENT NEEDS

    EPA Science Inventory

    Many small and rural water systems have both cost and quality problems. As drinking water quality standards become more stringent, costs will increase and both problems will be compounded. One economical alternative to conventional treatment is the package plant - a self containe...

  14. Application of two real-time toxicity tests to monitor Rocky Flats Plant water quality

    Microsoft Academic Search

    H. Wolaver; S. Spence; I. Paton

    1993-01-01

    Rocky Flats Plant (RFP) is part of the Department of Energy (DOE) nuclear weapons complex and fabricated weapon components for the DOE from 1952 to 1989. Like other industrial facilities, RFP is subject to Clean Water Act (CWA) regulations that require surface water discharge monitoring. Unlike most industrial facilities, RFP is also regulated under a Federal Facility Compliance Agreement (FFCA)

  15. Separating soil and leaf water 18O isotopic signals in plant stem cellulose

    Microsoft Academic Search

    Leonel da Silveira Lobo Sternberg; William T. Anderson; Kanema Morrison

    2003-01-01

    The oxygen-18 signal of soil and leaf water are both recorded in heterotrophically synthesized plant stem cellulose. Presently, these signals can only be teased apart with modeling and assumptions on the nature of the isotopic enrichment of leaf water. A method by which these two signals are chemically separated and analyzed is tested here. Heterotrophically synthesized cellulose from germinating seeds

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Waterhyacinth (Eichhornia crassipes (Mart.) Solms) can take up water nutrients sufficient for growth under highly variable conditions. Few studies have linked water and plant nutrients to measures of biological control in field populations. Fifteen sites in coastal Texas were sampled in 2003 and 2...

  17. Optimization of Water Consumption in Second Generation Bioethanol Plants

    E-print Network

    Grossmann, Ignacio E.

    looses by evaporation and drift in the cooling tower. Next, a number of technologies are considered the cooling needs and reducing the water loss by evaporation and drift in the cooling tower as shown recently is optimized in the production processes, which reduces the cooling needs of the processes and thus, the water

  18. Assessing Waste Water Treatment Plant Effluent for Thyroid Hormone Disruption

    EPA Science Inventory

    Much information has been coming to light on the estrogenic and androgenic activity of chemicals present in the waste water stream and in surface waters, but much less is known about the presence of chemicals with thyroid activity. To address this issue, we have utilized two assa...

  19. Innovative Fresh Water Production Process for Fossil Fuel Plants

    SciTech Connect

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

    2006-09-29

    This project concerns a diffusion driven desalination (DDD) process where warm water is evaporated into a low humidity air stream, and the vapor is condensed out to produce distilled water. Although the process has a low fresh water to feed water conversion efficiency, it has been demonstrated that this process can potentially produce low cost distilled water when driven by low grade waste heat. This report summarizes the progress made in the development and analysis of a Diffusion Driven Desalination (DDD) system. Detailed heat and mass transfer analyses required to size and analyze the diffusion tower using a heated water input are described. The analyses agree quite well with the current data and the information available in the literature. The direct contact condenser has also been thoroughly analyzed and the system performance at optimal operating conditions has been considered using a heated water/ambient air input to the diffusion tower. The diffusion tower has also been analyzed using a heated air input. The DDD laboratory facility has successfully been modified to include an air heating section. Experiments have been conducted over a range of parameters for two different cases: heated air/heated water and heated air/ambient water. A theoretical heat and mass transfer model has been examined for both of these cases and agreement between the experimental and theoretical data is good. A parametric study reveals that for every liquid mass flux there is an air mass flux value where the diffusion tower energy consumption is minimal and an air mass flux where the fresh water production flux is maximized. A study was also performed to compare the DDD process with different inlet operating conditions as well as different packing. It is shown that the heated air/heated water case is more capable of greater fresh water production with the same energy consumption than the ambient air/heated water process at high liquid mass flux. It is also shown that there can be significant advantage when using the heated air/heated water process with a less dense less specific surface area packed bed. Use of one configuration over the other depends upon the environment and the desired operating conditions.

  20. [Water treatment efficiency of constructed wetland plant-bed/ditch systems].

    PubMed

    Wang, Zhong-Qiong; Zhang, Rong-Bin; Chen, Qing-Hua; Wei, Hong-Bin; Wang, Wei-Dong

    2012-11-01

    Shijiuyang constructed wetland (SJY-CW) in Jiaxing City adopted plant-bed/ditch systems originated from the natural landscape as its major functioning unit. The constructed root channel technology (CRCT) is the core technique applied within the plant-bed/ditch systems. Monitoring results demonstrated that the wetland had the capability of improving water quality indexes by one rank grade according to the national environmental quality standards for surface water (GB 3838-2002). In order to optimize the water quality improvement function of plant-bed/ditch systems and CRCT, a pilot project in SJY-CW was constructed from May to October, 2010. The project contained 16 independent experimental cells. Orthogonal test design was applied to probe into the effects of constructed root channel layers, plant species combination, and reinforced physical substrates on promoting the water quality amelioration efficiency of the plant-bed/ditch systems. Comprehensively considering water treatment effects, construction difficulty, and construction and maintenance cost, the recommended optimal ways are as follows. Plant straws were preferably paved under subsurface zones by two layers with a gap of 20-30 cm. The preferable plant combination was reed (Phragmites australis) plus wild rice (Zizania caduciflora). Calcite might be applied as alternative reinforced media in some suitable sites of plant-bed/ditch systems. Water treatment effects were compared between pilot project and the whole wetland area of SJY-CW. The results showed that the reinforced pilot project exhibited higher treatment efficiency for nutrients than SJY-CW itself. The removal rates of total nitrogen, total phosphorus, and ammonia nitrogen were increased by about 20% - 40% in the pilot project. This suggested that SJY-CW could release its vast water treatment potential by means of increasing water flux through the subsurface root channel zones of plant beds. Therefore, some adjustment and control measures could be proposed to maintain the tradeoff balance between the potential release and maximization of wetland treatment efficiency and the treated water amount, such as constructing or modifying the hydraulic structures to regulate flow amount through large ditch, redistributing water flow and increasing the water head difference between the two sides of alternate small ditches. PMID:23323409