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1

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

PubMed

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

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

2013-01-01

2

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

NASA Technical Reports Server (NTRS)

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

Farbman, G. H.

1976-01-01

3

Are fire, soil fertility and toxicity, water availability, plant functional diversity, and litter decomposition related in a Neotropical savanna?  

PubMed

Understanding how biodiversity and ecosystem functioning respond to changes in the environment is fundamental to the maintenance of ecosystem function. In realistic scenarios, the biodiversity-ecosystem functioning path may account for only a small share of all factors determining ecosystem function. Here, we investigated the strength to which variations in environmental characteristics in a Neotropical savanna affected functional diversity and decomposition. We sought an integrative approach, testing a number of pairwise hypotheses about how the environment, biodiversity, and functioning were linked. We used structural equation modelling to connect fire frequency, soil fertility, exchangeable Al, water availability, functional diversity of woody plants, tree density, tree height, and litter decomposition rates in a causal chain. We found significant effects of soil nutrients, water availability, and Al on functional diversity and litter decomposition. Fire did not have a significant direct effect on functional diversity or litter decomposition. However, fire was connected to both variables through soil fertility. Functional diversity did not influence rates of litter decomposition. The mediated effects that emerged from pairwise interactions are encouraging not only for predicting the functional consequences of changes in environmental variables and biodiversity, but also to caution against predictions based on only environmental or only biodiversity change. PMID:24748157

Carvalho, Gustavo Henrique; Batalha, Marco Antônio; Silva, Igor Aurélio; Cianciaruso, Marcus Vinicius; Petchey, Owen L

2014-07-01

4

Thermochemical water decomposition processes  

NASA Technical Reports Server (NTRS)

Thermochemical processes which lead to the production of hydrogen and oxygen from water without the consumption of any other material have a number of advantages when compared to other processes such as water electrolysis. It is possible to operate a sequence of chemical steps with net work requirements equal to zero at temperatures well below the temperature required for water dissociation in a single step. Various types of procedures are discussed, giving attention to halide processes, reverse Deacon processes, iron oxide and carbon oxide processes, and metal and alkali metal processes. Economical questions are also considered.

Chao, R. E.

1974-01-01

5

Phlogopite Decomposition, Water, and Venus  

NASA Technical Reports Server (NTRS)

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.

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

2005-01-01

6

Proximate nutritive value changes during decomposition of salt marsh plants  

Microsoft Academic Search

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

Armando A. Cruz

1975-01-01

7

Decomposition of water hyacinth detritus in eutrophic lake water  

Microsoft Academic Search

A study was conducted to determine the seasonal production of detritus by water hyacinths [Eichhornia crassipes (Mart.) Sohns] cultured in eutrophic Lake Apopka water, and the decomposition of detritus in situ and under laboratory conditions. Annual averages for C, N and P deposited through detritus production at the sediment-water interface were 2870, 176 and 19 kg ha-1 yr-1, respectively.

K. R. Reddy; W. F. DeBusk

1991-01-01

8

Plant Identity Influences Decomposition through More Than One Mechanism  

PubMed Central

Plant litter decomposition is a critical ecosystem process representing a major pathway for carbon flux, but little is known about how it is affected by changes in plant composition and diversity. Single plant functional groups (graminoids, legumes, non-leguminous forbs) were removed from a grassland in northern Canada to examine the impacts of functional group identity on decomposition. Removals were conducted within two different environmental contexts (fertilization and fungicide application) to examine the context-dependency of these identity effects. We examined two different mechanisms by which the loss of plant functional groups may impact decomposition: effects of the living plant community on the decomposition microenvironment, and changes in the species composition of the decomposing litter, as well as the interaction between these mechanisms. We show that the identity of the plant functional group removed affects decomposition through both mechanisms. Removal of both graminoids and forbs slowed decomposition through changes in the decomposition microenvironment. We found non-additive effects of litter mixing, with both the direction and identity of the functional group responsible depending on year; in 2004 graminoids positively influenced decomposition whereas in 2006 forbs negatively influenced decomposition rate. Although these two mechanisms act independently, their effects may be additive if both mechanisms are considered simultaneously. It is essential to understand the variety of mechanisms through which even a single ecosystem property is affected if we are to predict the future consequences of biodiversity loss. PMID:21858210

McLaren, Jennie R.; Turkington, Roy

2011-01-01

9

Effect of water level drawdown on decomposition in boreal peatlands  

NASA Astrophysics Data System (ADS)

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.

Straková, Petra; Penttilä, Timo; Laiho, Raija

2010-05-01

10

Tremolite Decomposition and Water on Venus  

NASA Technical Reports Server (NTRS)

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.

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

2000-01-01

11

Elevated atmospheric carbon dioxide effects on cotton plant residue decomposition  

SciTech Connect

Assessing the impact of elevated atmospheric CO{sub 2} concentration on the global environment is hampered due to a lack of understanding of global C cycling. Carbon fixed within plant biomass ultimately enters the soil via plant residues, but the effects of elevated-CO{sub 2}-grown plant material on decomposition rates and long-term soil C storage are unknown. The objective of this study was to determine the decomposition rate of plant residues grown under an elevated CO{sub 2} environment as affected by soil type. Cotton (Gossypium hirsutum L. `Delta Pine 77`) samples were collected from a free-air CO{sub 2} enrichment (550 {mu}L L{sup -1}) experiment. The plant residues were incubated under ambient CO{sub 2} conditions to determine decomposition rates of leaves, stems, and roots and potential N and P mineralization-immobilization in three soil series. No significant difference was observed between plant residue grown under CO{sub 2} enrichment vs. ambient CO{sub 2} conditions for soil respiration or P mineralization-immobilization. Significantly greater net N immobilization was observed during the incubation in all soil types for plant residue grown at elevated CO{sub 2}. These results indicate that while decomposition of plant residue may not be reduced by CO{sub 2} enrichment, N dynamics may be markedly changed. 32 refs., 5 figs., 3 tabs.

Torbert, H.A. [USDA-ARS Blackland, Temple. TX (United States); Prior, S.A.; Rogers, H.H. [USDA-ARS National Soil Dynamics Lab., Auburn, AL (United States)

1995-09-01

12

Theoretical study of water cluster catalyzed decomposition of formic acid.  

PubMed

We have performed a number of quantum chemical simulations to examine water cluster catalyzed decomposition of formic acid. The decomposition of formic acid consists of two competing pathways, dehydration, and decarboxylation. We use the Gaussian 4 method of the Gaussian09 software to locate and optimize a transition state of the decomposition reaction and obtain the activation energy. The decomposition starts by transferring a proton of a formic acid to a water molecule. The de Broglie wavelength of a proton is similar to the width of the potential barrier of the decomposition reaction at low temperature. The tunneling, in which a proton penetrates the potential barrier, enhances the decomposition rate. Water molecules serve as the catalyst in the decomposition and reduce the activation energy. The relay of a proton from a water molecule to a neighboring water molecule is accomplished with little change of the geometry of a molecule, resulting in the reduction of the activation energy. Two water molecules are actively involved in the decomposition reaction to reduce the activation energy. We have also examined the effect of water clusters with three, four, and five water molecules on the decomposition reaction. The noncovalent distance between a hydrogen atom of a water molecule and an oxygen atom of a neighboring water molecule decreases in a water cluster due to the cooperative many-body interactions. A water molecule in a water cluster becomes a better proton donor as well as a better proton acceptor. The activation energy of the decomposition is further decreased by the catalytic effect of a water cluster. We calculate the reaction rate using the transition state theory corrected by the tunneling effect of a proton. The calculated reaction rate of the decarboxylation is smaller than that of the dehydration when less than three water molecules are included in the simulation. However, the major product of the decomposition of a formic acid becomes carbon dioxide and hydrogen molecule formed by the decarboxylation when a water cluster with more than four water molecules serves as catalyst in the decomposition of formic acid. PMID:24735438

Inaba, Satoshi

2014-04-24

13

Elevated atmospheric carbon dioxide effects on cotton plant residue decomposition  

Microsoft Academic Search

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

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

1995-01-01

14

Fear of predation slows plant-litter decomposition.  

PubMed

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

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

2012-06-15

15

Plant Water Relations  

NSDL National Science Digital Library

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

Bidlack, Jim

16

Decomposition of Plant Debris by the Nematophagous Fungus ARF.  

PubMed

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

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

2004-09-01

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

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

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

1996-01-01

18

Hydrogen peroxide deposition and decomposition in rain and dew waters  

NASA Astrophysics Data System (ADS)

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

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

19

Kinetics of the pyrolytic and hydrothermal decomposition of water hyacinth.  

PubMed

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

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

2011-07-01

20

Black carbon decomposition under varying water regimes  

Microsoft Academic Search

The stability of biomass-derived black carbon (BC) or biochar as a slow cycling pool in the global C cycle is an important property and is likely governed by environmental conditions. This study investigated the effects of water regimes (saturated, unsaturated and alternating saturated–unsaturated conditions) and differences in BC materials, produced by carbonizing corn residues and oak wood at two temperatures

Binh Thanh Nguyen; Johannes Lehmann

2009-01-01

21

Water Desalination Plant  

NSDL National Science Digital Library

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

Integrated Teaching And Learning Program

22

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

Microsoft Academic Search

Worldwide decomposition rates depend both on climate and the legacy of plant functional traits as litter quality. To quantify the degree to which functional differentiation among species affects their litter decomposition rates, we brought together leaf trait and litter mass loss data for 818 species from 66 decomposition experiments on six continents. We show that: (i) the magnitude of species-driven

William K. Cornwell; Johannes H. C. Cornelissen; K. Amatangalo; Ellen Dorrepaal; Valerie T. Eviner; Oscar Godoy; S. E. Hobbir; Bart Hoorens; Hiroko Kurokawa; N. Perez-Harguindeguy; Helen M. Quested; Louis S. Santiago; David A. Wardle; Ian J. Wright; Rien Aerts; Steven D. Allison; Bodegom van P. M; Victor Brovkin; Alex Chatain; Terry V. Callaghan; S. Diaz; Eric Garnier; Diego E. Gurvich; Elena Kazakou; Julia A. Klein; Jenny Read; Peter B. Reich; Nadejda A. Soudzilovskaia; M. Victoria Vaieretti; Mark Westoby

2008-01-01

23

Decomposition  

USGS Publications Warehouse

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.

Middleton, Beth A.

2014-01-01

24

Plant Water Relations.  

ERIC Educational Resources Information Center

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

Tomley, David

1982-01-01

25

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

NASA Astrophysics Data System (ADS)

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.

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

2012-12-01

26

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

PubMed

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

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

2001-03-19

27

[Decomposition interaction of mixed litter between Chinese fir and various accompanying plant species].  

PubMed

Studies on the decomposition of mixed litter between Chinese fir and 8 accompanying plant species showed that the decomposition of Chinese fir litter was promoted to different degrees by 8 mixed plant species, in which Angiopteris fokiensis had the greatest effect, while Schima superba had certain promotion first, but then, weak inhibition. The order of promotion was Angiopteris fokiensis > Maesa japonica > Ficus simplicissima > Woodwardia japonica > Boehmeria nivea > Castanopsis fargesii > Castanopsis fissa > Dicranopteris dicotoma. Chinese fir litter had a certain inhibition to litter decomposition of Schima superba and Castanopsis fissa, and certain promotion to litter decomposition of Castanopsis fargesii, but the interactions were not significant. There existed an interaction between Chinese fir and some plant species in the course of mixed decomposition. Therefore, rational protection and restoration of understory plant was important to fasten nutrient cycling of Chinese fir plantation ecosystem and to maintain soil fertility. PMID:11758404

Lin, K; Hong, W; Yu, X; Huang, B

2001-06-01

28

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

SciTech Connect

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

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

2010-01-01

29

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

30

Kinetic study of pyrolysis of waste water treatment plant sludge  

Microsoft Academic Search

Activated sewage sludge samples obtained from two different waste water treatment plants were investigated by thermogravimetric\\u000a analysis. Due to a very high content of water in the sludge samples, these had to be dried at 160°C in an electrical oven\\u000a in order to remove all adsorbed water. To ensure pyrolysis conditions, nitrogen atmosphere was applied. The pyrolysis decomposition\\u000a process was

LukᚠGašparovi?; Ivan Hrablay; Zuzana Vojteková; ?udovít Jelemenský

2011-01-01

31

Inorganic fertilizer enrichment of soil: effect on decomposition of plant litter under subhumid tropical conditions  

Microsoft Academic Search

Litter decomposition is controlled by many factors, including the quality of the litter and conditions within the soil environment.\\u000a The decomposition and N and P release from prunings of three agroforestry plant species (Sesbania sesban, Croton megalocarpus, and Calliandra calothyrsus) were evaluated on field plots which were amended with: (1) no fertilizer (control), (2) 120 kg N ha–1 applied as

A. B. Kwabiah; R. P. Voroney; C. A. Palm; N. C. Stoskopf

1999-01-01

32

Initial impacts of altered UVB radiation on plant growth and decomposition in shortgrass steppe  

Microsoft Academic Search

We initiated a study in winter 2000 in a Colorado shortgrass steppe to investigate effects of altered ultraviolet-B (UVB) radiation and altered precipitation on plant growth, plant tissue decomposition, and litter faunal activity. In the field, open-air structures were constructed of solid plastic sheet material that either passed all wavelengths of solar radiation or passed only wavelengths greater than 400

Jennifer Y. King; Daniel G. Milchunas; Arvin R. Mosier; John C. Moore; Meghan H. Quirk; Jack A. Morgan; James R. Slusser

2003-01-01

33

Above and belowground controls on litter decomposition in semiarid ecosystems: effects of solar radiation, water availability and litter quality  

NASA Astrophysics Data System (ADS)

The integrated controls on soil organic matter formation in arid and semiarid ecosystems are not well understood and appear to stem from a number of interacting controls affecting above- and belowground carbon turnover. While solar radiation has recently been shown to have an important direct effect on carbon loss in semiarid ecosystems as a result of photochemical mineralization of aboveground plant material, the mechanistic basis for photodegradative losses is poorly understood. In addition, there are large potential differences in major controls on above- and belowground decomposition in low rainfall ecosystems. We report on a mesocosm and field study designed to examine the relative importance of different wavelengths of solar radiation, water availability, position of senescent material above- and belowground and the importance of carbon litter quality in determining rates of abiotic and biotic decomposition. In a factorial experiment of mesocosms, we incubated leaf and root litter simultaneously above- and belowground and manipulated water availability with large and small pulses. Significant interactions between position-litter type and position-pulse sizes demonstrated interactive controls on organic mass loss. Aboveground decomposition showed no response to pulse size or litter type, as roots and leaves decomposed equally rapidly under all circumstances. In contrast, belowground decomposition was significantly altered by litter type and water pulses, with roots decomposing significantly slower and small water pulses reducing belowground decomposition. In the field site, using plastic filters which attenuated different wavelengths of natural solar radiation, we found a highly significant effect of radiation exclusion on mass loss and demonstrated that both UV-A and short-wave visible light can have important impacts on photodegradative carbon losses. The combination of position and litter quality effects on litter decomposition appear to be critical for the formation of soil organic matter and an integration of the relative importance of these processes could provide in the potential for carbon sequestration in arid and semiarid ecosystems.

Austin, A. T.; Araujo, P. I.; Leva, P. E.; Ballare, C. L.

2008-12-01

34

North City Water Reclamation Plant  

E-print Network

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

Prevedouros, Panos D.

35

Decomposition and nitrogen release of understorey plant residues in biological and integrated apple orchards under field conditions in New Zealand  

Microsoft Academic Search

In grassed-down apple orchards in New Zealand, the understorey vegetation is usually mown and the plant residues are returned to the orchard floors as a source of nutrients. It is, therefore, important to determine the decomposition pattern and the rate of N release from understorey plant residues. In this study, the decomposition and N release of surface-placed understorey plant residues

Shane S. Tutua; Kuan M. Goh; Mike J. Daly

2002-01-01

36

In situ monitoring of the effects of water quality on benthic detrital decomposition  

Microsoft Academic Search

Detrital decomposition is an important marine benthic process which contributes to the fertility of seas, particularly in estuarian and coastal waters. The process involves a complex community of microorganisms and small animals which interact with each other in a manner similar to that which occurs in forest litter and in composts. Plastic chambers for measuring decomposition rates of Spartina alterniflora

J. J. Lee; C. Mastropaolo; M. McEnery; J. H. Tietjen; J. Garrison

1978-01-01

37

Interactions among fungal community structure, litter decomposition and depth of water table in a cutover peatland.  

PubMed

Peatlands are important reservoirs of carbon (C) but our understanding of C cycling on cutover peatlands is limited. We investigated the decomposition over 18 months of five types of plant litter (Calluna vulgaris, Eriophorum angustifolium, Eriophorum vaginatum, Picea sitchensis and Sphagnum auriculatum) at a cutover peatland in Scotland, at three water tables. We measured changes in C, nitrogen (N) and phosphorus (P) in the litter and used denaturing gradient gel electrophoresis to investigate changes in fungal community composition. The C content of S. auriculatum litter did not change throughout the incubation period whereas vascular plant litters lost 30-40% of their initial C. There were no differences in C losses between low and medium water tables, but losses were always significantly less at the high water table. Most litters accumulated N and E. angustifolium accumulated significant quantities of P. C, N and P were significant explanatory variables in determining changes in fungal community composition but explained <25% of the variation. Litter type was always a stronger factor than water table in determining either fungal community composition or turnover of C, N and P in litter. The results have implications for the ways restoration programmes and global climate change may impact upon nutrient cycling in cutover peatlands. PMID:18430005

Trinder, Clare J; Johnson, David; Artz, Rebekka R E

2008-06-01

38

In Situ Monitoring of the Effects of Water Quality on Benthic Detrital Decomposition.  

National Technical Information Service (NTIS)

Detrital decomposition is an important marine benthic process which contributes to the fertility of seas, particularly in estuarian and coastal waters. The process involves a complex community of microorganisms and small animals which interact with each o...

J. J. Lee, C. Mastropaolo, M. McEnery, J. H. Tietjen, J. Garrison

1978-01-01

39

Biogeochemistry of Decomposition and Detrital Processing  

Microsoft Academic Search

Decomposition is a key ecological process that roughly balances net primary production in terrestrial ecosystems and is an essential process in resupplying nutrients to the plant community. Decomposition consists of three concurrent processes: communition or fragmentation, leaching of water-soluble compounds, and microbial catabolism. Decomposition can also be viewed as a sequential process, what Eijsackers and Zehnder (1990) compare to a

J. Sanderman; R. Amundson

2003-01-01

40

Plant Leaf Residue Decomposition, Nutrient Release and Soil Enzyme Activity  

Microsoft Academic Search

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

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

41

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

Microsoft Academic Search

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

E. Kristensen

1994-01-01

42

A unified Smith predictor based on the spectral decomposition of the plant  

Microsoft Academic Search

We point out a numerical problem in the well-known modified Smith predictor and propose a unified Smith predictor (USP) which overcomes this problem. The proposed USP combines the classical Smith predictor with the modified one, after a spectral decomposition of the plant. We then derive an equivalent representation of the original delay system, together with the USP. Based on this

Qing-Chang Zhong; George Weiss

2004-01-01

43

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.

44

Water Filtration Using Plant Xylem  

PubMed Central

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

Chambers, Valerie; Venkatesh, Varsha; Karnik, Rohit

2014-01-01

45

A Modal Decomposition of the Rotating Shallow Water Equations  

NASA Astrophysics Data System (ADS)

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

Poulin, Francis; Waite, Michael; Greig, Daniel

2013-04-01

46

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

E-print Network

. 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

Cai, Xiao-Chuan

47

Mechanisms of Decomposition of Organic Compounds by Water Plasmas at Atmospheric Pressure  

NASA Astrophysics Data System (ADS)

The decomposition of acetone, methanol, and ethanol by water plasmas at atmospheric pressure has been investigated using a direct current (DC) discharge. At torch powers of 910-1050 W and organic compound concentrations of 1-10 mol %, the decomposition rate of methanol was over 99.99%, while those of acetone and/or ethanol was 96-99%. The concentrations of H2 obtained were 65-71% in the effluent gas and the removal efficiencies of 90-95% for total organic carbon (TOC) were achieved in liquid effluent for any compounds by pyrolysis. Over 50 wt % carbon in acetone or ethanol fed as the plasma supporting gas was transformed into soot, while the soot formation was negligible during methanol decomposition. On the basis of the experimental results, the mechanisms of decomposition of organic compounds in water plasmas were proposed and the mechanism of soot formation was clarified for the first time.

Narengerile; Nishioka, Hiroshi; Watanabe, Takayuki

2011-08-01

48

Water Filtration Using Plant Xylem  

E-print Network

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, ...

Boutilier, Michael Stephen Ha

49

Plant transpiration distillation of water  

SciTech Connect

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

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

1986-01-01

50

Waste Water Plant Operators Manual.  

ERIC Educational Resources Information Center

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

Washington State Coordinating Council for Occupational Education, Olympia.

51

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

SciTech Connect

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

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

1999-08-01

52

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

PubMed

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

Schweizer; Fear; Cadisch

1999-07-01

53

Dual role of lignin in plant litter decomposition in terrestrial ecosystems  

PubMed Central

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

Austin, Amy T.; Ballare, Carlos L.

2010-01-01

54

Temperature and plant species control over litter decomposition in Alaskan tundra  

SciTech Connect

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

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

1996-11-01

55

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

DOEpatents

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

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

1983-02-08

56

Economic comparison of hydrogen production using sulfuric acid electrolysis and sulfur cycle water decomposition. Final report  

Microsoft Academic Search

An evaluation of the relative economics of hydrogen production using two advanced techniques was performed. The hydrogen production systems considered were the Westinghouse Sulfur Cycle Water Decomposition System and a water electrolysis system employing a sulfuric acid electrolyte. The former is a hybrid system in which hydrogen is produced in an electrolyzer which uses sulfur dioxide to depolarize the anode.

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

1978-01-01

57

WATER ANALYSIS WITH THE HELP OF TENSOR CANONICAL DECOMPOSITIONS J.-P. Royer  

E-print Network

precisely heavy metals like Pb, As and Co for example). Since january 2009, water samples have beenWATER ANALYSIS WITH THE HELP OF TENSOR CANONICAL DECOMPOSITIONS J.-P. Royer , P. Comon UniversitH, temperature, concentration of ions and heavy metals. Funded by a PhD support delivered by the University

Paris-Sud XI, Université de

58

Noise Decomposition in Boiling Water Reactors with Application to Stability Monitoring  

E-print Network

Noise Decomposition in Boiling Water Reactors with Application to Stability Monitoring J. Karlsson* and I. Pázsit Chalmers University of Technology, Department of Reactor Physics S-412 96 Göteborg, Sweden in boiling water reactor (BWR) noise measure- ments, based on flux factorization techniques (i.e., using

Pázsit, Imre

59

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

PubMed

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. PMID:20827492

Bengtsson, Jan; Janion, Charlene; Chown, Steven L; Leinaas, Hans Petter

2011-01-01

60

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

PubMed Central

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

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

2010-01-01

61

Effect of silver and copper ions on the decomposition of ozone in water  

NASA Astrophysics Data System (ADS)

Features of the kinetics of ozone decomposition in water at pH 2 are studied depending on the concentration of silver and copper ions that are present. The existence of a critical concentration of metal ions (˜3-6 × 10-6 M) is established, below which ions slow the rate of ozone decomposition and above which the accelerate the process. It is concluded that the first region is due to the capture of hydroxyl and other radicals by metal ions, inhibiting the chain of ozone decomposition in water. A further increase in the concentration of ions leads to dominance of their direct interaction with molecules of ozone. A mechanism for the process is proposed and the rate constants of reaction of ozone with silver ions and copper are calculated (0.033 and 0.06 M-1 s-1, respectively).

Ershov, B. G.; Morozov, P. A.; Gordeeev, A. V.

2012-12-01

62

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

PubMed

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

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

2013-06-01

63

Plant Responses to Water Stress  

PubMed Central

This Special Issue comprises a series of papers that develops the theme of plant responses to water stress, encompassing recent developments at the molecular level, through responses of photosynthesis and metabolism, to their application in crop selection and yield. The consideration of water deficits is particularly timely, given the huge developments in this area in the past decade. This issue specifically sets out to place molecular and physiological processes and their agronomic applications in an environmental context. PMID:12102505

GRIFFITHS, H.; PARRY, M. A. J.

2002-01-01

64

Modeling water use at thermoelectric power plants  

E-print Network

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

Rutberg, Michael J. (Michael Jacob)

2012-01-01

65

Carbon isotopic fractionation during decomposition of plant materials of different quality  

NASA Astrophysics Data System (ADS)

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

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

2003-09-01

66

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

E-print Network

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

Roca, Rémy

67

Decomposition and plant-available nitrogen in biosolids: laboratory studies, field studies, and computer simulation.  

PubMed

This research combines laboratory and field studies with computer simulation to characterize the amount of plant-available nitrogen (PAN) released when municipal biosolids are land-applied to agronomic crops. In the laboratory studies, biosolids were incubated in or on soil from the land application sites. Mean biosolids total C, organic N, and C to N ratio were 292 g kg(-1), 41.7 g kg(-1), and 7.5, respectively. Based on CO2 evolution at 25 degrees C and optimum soil moisture, 27 of the 37 biosolids-soil combinations had two decomposition phases. The mean rapid and slow fraction rate constants were 0.021 and 0.0015 d(-1), respectively, and the rapid fraction contained 23% of the total C assuming sequential decomposition. Where only one decomposition phase existed, the mean first order rate constant was 0.0046 d(-1). The mean rate constant for biosolids stored in lagoons for an extended time was 0.00097 d(-1). The only treatment process that was related to biosolids treatment was stabilization by storage in a lagoon. Biosolids addition rates (dry basis) ranged from 1.3 to 33.8 Mg ha(-1) with a mean value of 10.6 Mg ha(-1). A relationship between fertilizer N rate and crop response was used to estimate observed PAN at each site. Mean observed PAN during the growing season was 18.9 kg N Mg(-1) or 37% of the biosolids total N. Observed PAN was linearly related to biosolids total N. Predicted PAN using the computer model Decomposition, actual growing-season weather, actual analytical data, and laboratory decomposition kinetics compared well with observed PAN. The mean computer model prediction of growing-season PAN was 19.2 kg N Mg(-1) and the slope of the regression between predicted and observed PAN was not significantly different from unity. Predicted PAN obtained using mean decomposition kinetics was related to predicted PAN using actual decomposition kinetics suggesting that mean rate constants, actual weather, and actual analytical data could be used in estimation of PAN. There was a linear relationship between predicted N mineralization for the growing season and for the first year. For this study, the mean values for the growing season and year were 27 and 37% of the organic N, respectively. PMID:12931907

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

2003-01-01

68

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

PubMed

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

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

2014-10-01

69

Genotypic diversity of an invasive plant species promotes litter decomposition and associated processes.  

PubMed

Following studies that showed negative effects of species loss on ecosystem functioning, newer studies have started to investigate if similar consequences could result from reductions of genetic diversity within species. We tested the influence of genotypic richness and dissimilarity (plots containing one, three, six or 12 genotypes) in stands of the invasive plant Solidago canadensis in China on the decomposition of its leaf litter and associated soil animals over five monthly time intervals. We found that the logarithm of genotypic richness was positively linearly related to mass loss of C, N and P from the litter and to richness and abundance of soil animals on the litter samples. The mixing proportion of litter from two sites, but not genotypic dissimilarity of mixtures, had additional effects on measured variables. The litter diversity effects on soil animals were particularly strong under the most stressful conditions of hot weather in July: at this time richness and abundance of soil animals were higher in 12-genotype litter mixtures than even in the highest corresponding one-genotype litter. The litter diversity effects on decomposition were in part mediated by soil animals: the abundance of Acarina, when used as covariate in the analysis, fully explained the litter diversity effects on mass loss of N and P. Overall, our study shows that high genotypic richness of S. canadensis leaf litter positively affects richness and abundance of soil animals, which in turn accelerate litter decomposition and P release from litter. PMID:24276771

Wang, Xiao-Yan; Miao, Yuan; Yu, Shuo; Chen, Xiao-Yong; Schmid, Bernhard

2014-03-01

70

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

PubMed Central

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

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

2013-01-01

71

Method of generating hydrogen by catalytic decomposition of water  

DOEpatents

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

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

2002-01-01

72

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

NASA Astrophysics Data System (ADS)

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

Dijkstra, F. A.; Cheng, W.

2005-12-01

73

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

E-print Network

and colonization patterns ofcarrion in contrasting habitats, with important implications for forensic entomology. KEY WORDS carrion, decomposition, Calliphoridae, forensic entomology THE LARGE BODY of literatureSeasonal Colonization and Decomposition of Rat Carrion in Water and on Land in an Open Field

Tomberlin, Jeff

74

Decomposition of environmentally persistent perfluorooctanoic acid in water by photochemical approaches.  

PubMed

The decomposition of persistent and bioaccumulative perfluorooctanoic acid (PFOA) in water by UV-visible light irradiation, by H202 with UV-visible light irradiation, and by a tungstic heteropolyacid photocatalyst was examined to develop a technique to counteract stationary sources of PFOA. Direct photolysis proceeded slowly to produce CO2, F-, and short-chain perfluorocarboxylic acids. Compared to the direct photolysis, H2O2 was less effective in PFOA decomposition. On the other hand, the heteropolyacid photocatalyst led to efficient PFOA decomposition and the production of F- ions and CO2. The photocatalyst also suppressed the accumulation of short-chain perfluorocarboxylic acids in the reaction solution. PFOA in the concentrations of 0.34-3.35 mM, typical of those in wastewaters after an emulsifying process in fluoropolymer manufacture, was completely decomposed by the catalyst within 24 h of irradiation from a 200-W xenon-mercury lamp, with no accompanying catalyst degradation, permitting the catalyst to be reused in consecutive runs. Gas chromatography/mass spectrometry (GC/MS) measurements showed no trace of environmentally undesirable species such as CF4, which has a very high global-warming potential. When the (initial PFOA)/(initial catalyst) molar ratio was 10: 1, the turnover number for PFOA decomposition reached 4.33 over 24 h of irradiation. PMID:15573615

Hori, Hisao; Hayakawa, Etsuko; Einaga, Hisahiro; Kutsuna, Shuzo; Koike, Kazuhide; Ibusuki, Takashi; Kiatagawa, Hiroshi; Arakawa, Ryuichi

2004-11-15

75

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

PubMed

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

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

2011-10-01

76

MINI PILOT PLANT FOR DRINKING WATER RESEARCH  

EPA Science Inventory

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

77

Plant responses to water stress  

PubMed Central

Terrestrial plants most often encounter drought stress because of erratic rainfall which has become compounded due to present climatic changes.Responses of plants to water stress may be assigned as either injurious change or tolerance index. One of the primary and cardinal changes in response to drought stress is the generation of reactive oxygen species (ROS), which is being considered as the cause of cellular damage. However, recently a signaling role of such ROS in triggering the ROS scavenging system that may confer protection or tolerance against stress is emerging. Such scavenging system consists of antioxidant enzymes like SOD, catalase and peroxidases, and antioxidant compounds like ascorbate, reduced glutathione; a balance between ROS generation and scavenging ultimately determines the oxidative load. As revealed in case of defence against pathogen, signaling via ROS is initiated by NADPH oxidase-catalyzed superoxide generation in the apoplastic space (cell wall) followed by conversion to hydrogen peroxide by the activity of cell wall-localized SOD. Wall peroxidase may also play role in ROS generation for signaling. Hydrogen peroxide may use Ca2+ and MAPK pathway as downstream signaling cascade. Plant hormones associated with stress responses like ABA and ethylene play their role possibly via a cross talk with ROS towards stress tolerance, thus projecting a dual role of ROS under drought stress. PMID:22057331

Kar, Rup Kumar

2011-01-01

78

Behavior of microcystins and its decomposition product in water treatment process  

Microsoft Academic Search

Microcystins are well known as a liver tumor promotors. Recently, we identified (2S, 3S, 8S)-3-amino-2,6,8-trimethyl-10-phenyldeca-4E, 6E-dienoic acid (DmADDA) as the decomposition product of microcystins by iron(III) chloride in vitro. Therefore, we measured the level of microcystins and DmADDA in the water purification facility for a year. DmADDA was not only detected in the surface water without toxic blue-green algae, but

Shigeyuki Takenaka; Yoshito Tanaka

1995-01-01

79

DFT Study of Water Adsorption and Decomposition on a Ga-Rich GaP(001)(24) Surface  

E-print Network

DFT Study of Water Adsorption and Decomposition on a Ga-Rich GaP(001)(2Ã?4) Surface Seokmin Jeon investigate the adsorption and decomposition states of a water molecule on a Ga-rich GaP(001)(2Ã?4) surface using the PBE flavor of density functional theory (DFT). We selected the GaP(001)(2Ã?4) mixed dimer

Atwater, Harry

80

Thermal decomposition of zirconium-yttrium citric complexes prepared in ethylene glycol and water media  

SciTech Connect

The thermal decomposition of Y-Zr citric complexes prepared in ethylene glycol or in water medium is studied. The compositions of 'aqueous' Y-, Zr- and YZr complexes are determined and the corresponding IR spectra are analyzed. Proofs are put in concerning the mixed-metal nature of the complexes. Based on TG, DTG and DTA analyses as well as on some intermediates identified, certain schemes are proposed concerning the processes involved in the thermal decomposition of the complexes studied. The crystal structure, crystallites size, specific surface area and the morphology of the final yttria stabilized zirconia are determined; the influences of the preparation mode and of the precursors calcination temperature on the characteristics mentioned are studied.

Petrova, Nikolina [University of Sofia, Faculty of Chemistry, 1, J. Bourchier Blvd., Sofia 1164 (Bulgaria)]. E-mail: nhnp@wmail.chem.uni-sofia.bg; Todorovsky, Dimitar [University of Sofia, Faculty of Chemistry, 1, J. Bourchier Blvd., Sofia 1164 (Bulgaria)

2006-03-09

81

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...

82

Modelling Water in Crops and Plant Ecosystems  

Microsoft Academic Search

A water submodel is described that is specifically designed for use with plant growth simulators that represent internal plant substrates and variable shoot:root partitioning. The model calculates water flow from soil to root, root to shoot, and shoot to the atmosphere, for a closed-canopy situation. As presented here, the model has three state variables: the masses of water in the

J. H. M. THORNLEY

1996-01-01

83

Water Balance in Terrestrial PlantsWater Balance in Terrestrial Plants Water Regulation on LandWater Regulation on Land --PlantsPlants WWipip= W= Wrr + W+ Waa --WWtt --WWss  

E-print Network

1 Water Balance in Terrestrial PlantsWater Balance in Terrestrial Plants Water Regulation on LandWater waters internal water WWrr =Roots=Roots WWaa = Air= Air WWtt = Transpiration= Transpiration WWss = Secretions= Secretions Water Regulation on Land - Plants Water Balance in Terrestrial PlantsWater Balance

Cochran-Stafira, D. Liane

84

n Body Decomposition Approach to the Calculation of Interaction Energies of Water Clusters  

Microsoft Academic Search

A new methodology is proposed in which large basis set MP2-level calculations can be extended\\u000a to water clusters with as many as 50 monomers. The computationally prohibitive scaling of traditional\\u000a MP2 calculations is avoided by the use of an n-body decomposition\\u000a (NBD) description of the cluster binding energy. The computational efficiency of the NBD approach\\u000a is demonstrated by the application of the

R. A. Christie; K. D. Jordan

85

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

PubMed Central

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

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

2011-01-01

86

Water protection in coke-plant design  

SciTech Connect

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

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

2009-07-15

87

Controls on organic carbon preservation: The use of stratified water bodies to compare intrinsic rates of decomposition in oxic and anoxic systems  

Microsoft Academic Search

The relation between productivity, O 2 and organic carbon preservation has been the subject of great controversy. One theory has been that anoxic decomposition of organic matter is intrinsically slower than oxic decomposition and thus results in the accumulation of organic carbon in anoxic sediments and waters. However, several past studies suggest that differences in the intrinsic rates of decomposition

Cindy Lee

1992-01-01

88

Regulation of Water in Plant Cells  

ERIC Educational Resources Information Center

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

Kowles, Richard V.

2010-01-01

89

Find Out How Plants Use Water  

NSDL National Science Digital Library

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.

Dynamo

2012-01-01

90

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

SciTech Connect

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.

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

1982-05-01

91

Effects of Acid on Plant Litter Decomposition in an Arctic Lake  

PubMed Central

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

McKinley, Vicky L.; Vestal, J. Robie

1982-01-01

92

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

PubMed Central

Background and Aims Fine root decomposition is an important determinant of nutrient and carbon cycling in grasslands; however, little is known about the factors controlling root decomposition among species. Our aim was to investigate whether interspecific variation in the potential decomposition rate of fine roots could be accounted for by root chemical and morphological traits, life history and taxonomic affiliation. We also investigated the co-ordinated variation in root and leaf traits and potential decomposition rates. Methods We analysed potential decomposition rates and the chemical and morphological traits of fine roots on 18 Mediterranean herbaceous species grown in controlled conditions. The results were compared with those obtained for leaves in a previous study conducted on similar species. Key Results Differences in the potential decomposition rates of fine roots between species were accounted for by root chemical composition, but not by morphological traits. The root potential decomposition rate varied with taxonomy, but not with life history. Poaceae, with high cellulose concentration and low concentrations of soluble compounds and phosphorus, decomposed more slowly than Asteraceae and Fabaceae. Patterns of root traits, including decomposition rate, mirrored those of leaf traits, resulting in a similar species clustering. Conclusions The highly co-ordinated variation of roots and leaves in terms of traits and potential decomposition rate suggests that changes in the functional composition of communities in response to anthropogenic changes will strongly affect biogeochemical cycles at the ecosystem level. PMID:22143881

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

2012-01-01

93

Modified QR decomposition to avoid non-uniqueness in water supply networks with extension to adjoint calculus  

Microsoft Academic Search

The dynamic simulation and optimization of water supply networks contains various difficulties. One of them is that a classical modelling may yield singularities in the form of non-unique solutions. In , the application of singular value decomposition (SVD) is proposed in the context of water supply networks. Since the SVD of a matrix is computationally very expensive, we introduce an approach

Oliver Kolb; Pia Domschke; Jens Lang

2010-01-01

94

Effects of polyacrylamide, biopolymer, and biochar on decomposition of soil organic matter and 14C-labeled plant residues as determined by enzyme activities  

NASA Astrophysics Data System (ADS)

Application of polymers for the improvement of aggregate structure and reduction of soil erosion may alter the availability and decomposition of plant residues. In this study, we assessed the effects of anionic polyacrylamide (PAM), synthesized biopolymer (BP), and biochar (BC) on the decomposition of 14C-labeled maize residue in sandy and sandy loam soils. Specifically, PAM and BP with or without 14C-labeled plant residue were applied at 400 kg ha-1, whereas BC was applied at 5000 kg ha-1, after which the soils were incubated for 80 days at 22 oC. Initially, plant residue decomposition was much higher in untreated sandy loam soil than in sandy soil. Nevertheless, the stimulating effects of BP and BC on the decomposition of plant residue were more pronounced in sandy soil, where it accounted for 13.4% and 23.4% of 14C input, respectively, whereas in sandy loam soil, the acceleration of plant residue decomposition by BP and BC did not exceed 2.6% and 14.1%, respectively, compared to untreated soil with plant residue. The stimulating effects of BP and BC on the decomposition of plant residue were confirmed based on activities of ?-cellobiohydrolase, ?-glucosidase, and chitinase in both soils. In contrast to BC and BP, PAM did not increase the decomposition of native or added C in both soils.

Mahmoud Awad, Yasser; Ok, Young Sik; Kuzyakov, Yakov

2014-05-01

95

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

Microsoft Academic Search

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

Wolfgang Kundt; Eva Gruber

2006-01-01

96

A Trip to the Water Plant.  

ERIC Educational Resources Information Center

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…

Laskey, Marilyn

97

Influence of water potential on decomposition of soil organic matter in high elevation meadows  

NASA Astrophysics Data System (ADS)

High elevation meadows of the Sierra Nevada, California are defined by the presence of a high water table throughout the growing season. This definition takes into account the natural drawdown of most meadow systems during the summer months to within a few feet of the surface. The cyclic drawdown/recharge of the meadow water table, as well as local hydrologic gradient that exists in most meadow systems (ranging from xeric to hydric) impose important controls on organic matter storage and decomposition in these systems. In this study we incubated soils from the xeric, mesic and hydric regions of a subalpine Sierra Nevada meadow at five different water potentials and measured the CO2 flux at intervals over one year. We found that the cumulative carbon mineralization was greatest at the lowest (0.1 bar) and highest (4 bar) water potentials, across all regions of the meadow, suggesting a microbial response threshold that is reached as the soil dries. Soils from the hydric meadow regions showed the largest response to extreme drying of the soil. These results highlight the importance of soil moisture in regulating soil respiration in these systems and different levels of microbial activity when these soils are wet vs. dry. While normal conditions in these systems keep water potentials low (< 0.2 bar), future drought conditions can potentially increase the level of dryness in the meadows to the point where rapid carbon loss can be expected.

Arnold, C. L.; Ghezzehei, T. A.; Berhe, A.

2013-12-01

98

Production of hydrogen by direct thermal decomposition of water - Preliminary investigations  

NASA Astrophysics Data System (ADS)

Preliminary results from examinations of two techniques to effect solar thermal decomposition of water and then prevent recombination, as part of the French PIRDES program, are reported. A solar furnace simulator was fabricated with a 4 kW lamp shining light on elliptic mirrors which redirected the light to a focus to produce temperatures of 3000 K. Reaction studies have shown that significant hydrogen evolution occurs only at temperatures above 2000 K. Water injected into a zirconia nozzle at the focus rose to 2300 K and began dissociating within 0.001-0.01 sec. One experiment comprised water vapor with argon gas, pure water, and two types of nozzles (one perforated). Evolved hydrogen increased with increased stirring of the water feed, but decreased with increasing flow rate. Use of membrane semipermeable to oxygen around the zirconia nozzle demonstrated that the hydrogen flow rate depended on the electrical characteristics of the membrane. Good agreement was found between theoretical predictions and the hydrogen evolution rates in all the configurations.

Lede, J.; Lapicque, F.; Villermaux, J.; Cales, B.; Ounalli, A.; Baumard, J. F.; Anthony, A. M.

99

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

PubMed

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

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

2003-01-15

100

Plant to buy solar-heated water  

SciTech Connect

An investor-owned solar-energy company, Solar King, will sell hot water to a Wisconsin plant at a price guaranteed at 20% below the plant's cost to heat its own water with gas or No. 6 fuel oil. After 10 years, the plant may purchase the equipment which Solar King installed adjacent to the plant, or it may either extend or terminate the contract. The system includes the 900 32-square-foot collectors, three storage tanks with a combined 80,000-gallon capacity, a heat exchanger, pumps which are automatically activated, and a pumphouse. The arrangement with Solar King eliminates the need for front-end investment. (DCK)

Galvin, C.

1983-01-24

101

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

Microsoft Academic Search

The cultivation of genetically modified Bt maize has raised environmental concerns, as large amounts of plant residues remain in the field and may negatively impact\\u000a the soil ecosystem. In a field experiment, decomposition of leaf residues from three genetically modified (two expressing\\u000a the Cry1Ab, one the Cry3Bb1 protein) and six non-transgenic hybrids (the three corresponding non-transformed near-isolines\\u000a and three conventional

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

2010-01-01

102

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

Microsoft Academic Search

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

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

2007-01-01

103

Hydroelectric plant integrated with foul waters  

NASA Astrophysics Data System (ADS)

The foul water plant, the object of this work, involves the energy exploitation of the waters from two torrents and the foul water of a town in Southern Italy. The plant layout is such that it enables, moreover, the use of the same hydraulic works to supply irrigation water in the summer to farmers who work near the proposed mini-power station. With the aim of also carrying out an economic financial evaluation, the technical choices have been economically quantified and the outcome of these analyses have provided positive indications.

Fragiacomo, P.; Scornaienchi, N. M.

2005-09-01

104

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

NASA Astrophysics Data System (ADS)

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

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

2014-03-01

105

Water/Wastewater Treatment Plant Operator Qualifications.  

ERIC Educational Resources Information Center

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)

Water and Sewage Works, 1979

1979-01-01

106

Understanding Beijing's water challenge: a decomposition analysis of changes in Beijing's water footprint between 1997 and 2007.  

PubMed

Beijing has been experiencing increasing water shortage alongside its astonishing economic growth over the past decades. This study conducts a quasi-dynamic input-output (IO) analysis to investigate changes in Beijing's water footprint (WF) and decompose the effects of contributing factors to the changes during 1997-2007. The analysis distinguishes "internal" and "external" WF to depict connections of Beijing's water use with outside. The results show an increase in Beijing's WF from 4342 million m(3) in 1997 to 5748 million m(3) in 2007. Almost all the increase was attributable to the expansion of the external WF, while the internal WF only changed slightly, indicating a growing dependence of Beijing on external water resources. The decomposition analysis reveals that the technological effect was the principal contributor to offset the WF increase and the structural effect stemmed from the shift of demand toward products of the tertiary industries also contributed to reducing the WF. However, these effects were not sufficient to reverse the expansion of Beijing's WF resulted from the scale effect induced by expansion of final demand and the economic system efficiency effect associated with the growth of trade between Beijing and outside. The study provides insights into Beijing's water challenge and sheds lights on the combating strategies for the future. It is also an endeavor to enhance the policy relevance of the WF studies. PMID:23127171

Zhang, Zhuoying; Shi, Minjun; Yang, Hong

2012-11-20

107

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

NASA Astrophysics Data System (ADS)

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

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

2011-12-01

108

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

EPA Science Inventory

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

109

Water management and productivity in planted forests  

NASA Astrophysics Data System (ADS)

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

Nettles, J. E.

2014-09-01

110

Microbiological quality of drinking water at eight water treatment plants  

Microsoft Academic Search

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°C,

Gamila E. El-Taweel; Ahmad M. Shaban

2001-01-01

111

Synergistic effect of plasmacatalyst and ozone in a pulsed corona discharge reactor on the decomposition of organic pollutants in water  

Microsoft Academic Search

Plasmacatalytic effects of ?-alumina, ?-alumina, and silica gel in a pulsed corona discharge (PCD) reactor on the decomposition of aqueous methylene blue are described. Methylene blue concentration in the effluent was reduced to 23% of the inlet concentration by PCDs in water. Under the same experimental conditions, addition of ?-alumina further reduced it to 8%, ?-alumina to 4%, and silica

Muhammad Arif Malik

2003-01-01

112

Generalized k-space decomposition with chemical shift correction for non-Cartesian water-fat imaging.  

PubMed

Chemical-shift artifacts associated with non-Cartesian imaging are more complex to model and less clinically acceptable than the bulk fat shift that occurs with conventional spin-warp Cartesian imaging. A novel k-space based iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL) approach is introduced that decomposes multiple species while simultaneously correcting distortion of off-resonant species. The new signal model accounts for the additional phase accumulated by off-resonant spins at each point in the k-space acquisition trajectory. This phase can then be corrected by adjusting the decomposition matrix for each k-space point during the final IDEAL processing step with little increase in reconstruction time. The technique is demonstrated with water-fat decomposition using projection reconstruction (PR)/radial, spiral, and Cartesian spin-warp imaging of phantoms and human subjects, in each case achieving substantial correction of chemical-shift artifacts. Simulations of the point-spread-function (PSF) for off-resonant spins are examined to show the nature of the chemical-shift distortion for each acquisition. Also introduced is an approach to improve the signal model for species which have multiple resonant peaks. Many chemical species, including fat, have multiple resonant peaks, although such species are often approximated as a single peak. The improved multipeak decomposition is demonstrated with water-fat imaging, showing a substantial improvement in water-fat separation. PMID:18429018

Brodsky, Ethan K; Holmes, James H; Yu, Huanzhou; Reeder, Scott B

2008-05-01

113

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

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

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

2000-01-01

114

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

NASA Astrophysics Data System (ADS)

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

Biswas, Rajib; Furtado, Jonathan; Bagchi, Biman

2013-10-01

115

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

E-print Network

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.

Wolfgang Kundt; Eva Gruber

2006-03-17

116

Effect of Adsorbed Water on the Catalytic Decomposition of Hydrocarbons (by a Molecular Beam Method)  

Microsoft Academic Search

BY using true molecular beams of various hydrocarbons projected on to a platinum filament (4 mm.2 heated area) of known and controllable temperature, we have studied the primary decompositions instantaneously by pressure variations in the filament chamber, which is large compared with the filament. Similar decompositions at a carbon surface have also been studied, the carbon surface consisting of a

Otto Beeck

1935-01-01

117

[Purification of eutrophicated water by aquatic plant].  

PubMed

In this study, aquatic plants were used to control the pollution of eutrophicated water. The results showed that aquatic plants had a higher ability to remove total nitrogen (TN), total phosphorus (TP) and nitrate nitrogen. Among them, foxtail alga (Myriophyllum verticillatum) and grain leaf pondweed (Potamogeton maackianus) could effectively remove TN (83.84% and 77.54%), TP (91.3%) and nitrate nitrogen (95.85% and 90.65%), but had no significant effect on removing ammonia nitrogen (only 14% to 70%). Sediment shielded by plastic could prolong the release of the nutrients from it for 15 to 20 days, and show the compensation effect later. The results also showed that aquatic plants could greatly improve the transparency of water, but could not improve the COD and DO of water effectively. PMID:15574005

Tong, Chanhua; Yang, Xiao'e; Pu, Peimin

2004-08-01

118

Decomposition of litter produced under elevated CO 2 : Dependence on plant species and nutrient supply  

Microsoft Academic Search

We investigated the effect of CO2 concentration and soilnutrient availability during growth on the subsequent decomposition andnitrogen (N) release from litter of four annual grasses that differ inresource requirements and native habitat. Vulpia microstachys isa native grass found on California serpentine soils, whereas Avenafatua, Bromus hordaceus, and Lolium multiflorum areintroduced grasses restricted to more fertile sandstone soils (Hobbs & Mooney

VALERIE M. FRANCK; BRUCE A. HUNGATE; F. STUART CHAPIN; CHRISTOPHER B. FIELD

1997-01-01

119

Beneath the Arctic Green: Have recent increases in plant production been offset by increases in soil decomposition?  

NASA Astrophysics Data System (ADS)

Observational and modeling studies suggest that boreal vegetation has undergone an increase in plant production and C uptake in recent decades, coincident with increases in regional air temperatures, atmospheric CO2 concentration, and fire/successional dynamics. In the North American boreal forest, wildfires have increased in extent, season length, and depth of burn, driving higher C emission from black spruce ecosystems. Meanwhile, responses in soil systems that dictate the net ecosystem carbon (C) balance are less well known, in part owing to problems with elucidating the relatively small signals of organic matter decomposition from the large C fluxes of gross primary production and ecosystem respiration. Here, we measured net C accumulation in soils from Interior Alaska using radiocarbon (14C), lead isotopes (210Pb), cesium isotopes (137Cs), and time sequences of forest regeneration (fire and thaw chronosequences). We use soil 14C and non-steady-state models to estimate turnover times for soil organic C. Over the past century, rates of soil C uptake based on upland chronosequences ranged from -20 to -30 g C/m2/yr, but regionally likely shifted toward a reduced sink or source of - 20 to + 10 g C/m2/yr in recent decades due to increased combustion losses and deep C mobilization associated with permafrost thaw. C accumulation rates in lowland thermokarst chronosequences suggest a mixed sink/source effect, with post-thaw increases in surface accumulation potentially offset by decomposition at depth, or enhanced initial decomposition of C from previously frozen soils, followed by long-term net uptake of post-thaw peat. Large uncertainties remain regarding the turnover of soil organic C in boreal soil, yet enhanced decomposition has likely offset the increase in NPP, resulting in a reduced sink activity relative to pre1960s.

Harden, J. W.; O'Donnell, J.; Fuller, C.; Sierra, C. A.; Johnson, K. D.; Manies, K.; Jorgenson, T.; Jones, M.; Ewing, S. A.; Yue, C.; Turetsky, M.

2013-12-01

120

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

SciTech Connect

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.

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

1985-11-21

121

Streambank plants vital to water quality  

SciTech Connect

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

Sherman, H.

1989-08-01

122

Nonadditive effects of litter mixtures on decomposition and correlation with initial litter N and P concentrations in grassland plant species of northern China  

Microsoft Academic Search

We studied the occurrence of nonadditive effects of litter mixtures on the decomposition (the deviation of decomposition rate\\u000a of litter mixtures from the expected values based on the arithmetic means of individual litter types) of litters from three\\u000a plant species (i.e., Stipa krylovii Roshev., Artemisia frigida Willd., and Allium bidentatum Fisch. ex Prokh. & Ikonn.-Gal.) endemic to the grassland ecosystems

Ping Liu; Osbert J. Sun; Jianhui Huang; Linghao Li; Xingguo Han

2007-01-01

123

Water Movement in Vascular Plants: A Primer  

E-print Network

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

Sane, Sanjay P

2011-01-01

124

Moisture drives surface decomposition in thawing tundra  

NASA Astrophysics Data System (ADS)

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.

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

2013-07-01

125

CHEMICAL DOSER FOR AGUACLARA WATER TREATMENT PLANTS  

EPA Science Inventory

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

126

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.

127

ASSESSING POWER PLANT COOLING WATER INTAKE SYSTEM  

E-print Network

ASSESSING POWER PLANT COOLING WATER INTAKE SYSTEM ENTRAINMENT IMPACTS Prepared For: California that the uses of this information will not infringe upon privately owned rights. This report has not been and recognizing the importance of publishing this work so it could be used by other researchers and decision

128

WATER REUSE IN A PAPER REPROCESSING PLANT  

EPA Science Inventory

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

129

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...

130

K-Reactor water plant analysis  

Microsoft Academic Search

The reliability of the K-Reactor water plants has been reviewed by Research and Engineering personnel; this study augments a brief analysis of the KW generator failures incident given in my letter of October 6, 1958. Our attention has been directed largely to ascertaining the requirements of the system, the consequences of possible component failures, giving general assessment of the primary

Dickeman

1958-01-01

131

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

Microsoft Academic Search

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

V. L. McKinley; J. R. Vestal

1982-01-01

132

Synergistic effect of plasmacatalyst and ozone in a pulsed corona discharge reactor on the decomposition of organic pollutants in water  

Microsoft Academic Search

Plasmacatalytic effects of alpha-alumina, gamma-alumina, and silica gel in a pulsed corona discharge (PCD) reactor on the decomposition of aqueous methylene blue are described. Methylene blue concentration in the effluent was reduced to 23% of the inlet concentration by PCDs in water. Under the same experimental conditions, addition of alpha-alumina further reduced it to 8%, gamma-alumina to 4%, and silica

Muhammad Arif Malik

2003-01-01

133

Mobile water treatment plant special study  

SciTech Connect

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

Not Available

1992-12-01

134

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

PubMed

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

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

2013-04-01

135

Decomposition analysis of water footprint changes in a water-limited river basin: a case study of the Haihe River basin, China  

NASA Astrophysics Data System (ADS)

Decomposition analysis of water footprint (WF) changes, or assessing the changes in WF and identifying the contributions of factors leading to the changes, is important to water resource management. Instead of focusing on WF from the perspective of administrative regions, we built a framework in which the input-output (IO) model, the structural decomposition analysis (SDA) model and the generating regional IO tables (GRIT) method are combined to implement decomposition analysis for WF in a river basin. This framework is illustrated in the WF in Haihe River basin (HRB) from 2002 to 2007, which is a typical water-limited river basin. It shows that the total WF in the HRB increased from 4.3 × 1010 m3 in 2002 to 5.6 × 1010 m3 in 2007, and the agriculture sector makes the dominant contribution to the increase. Both the WF of domestic products (internal) and the WF of imported products (external) increased, and the proportion of external WF rose from 29.1 to 34.4%. The technological effect was the dominant contributor to offsetting the increase of WF. However, the growth of WF caused by the economic structural effect and the scale effect was greater, so the total WF increased. This study provides insights about water challenges in the HRB and proposes possible strategies for the future, and serves as a reference for WF management and policy-making in other water-limited river basins.

Zhi, Y.; Yang, Z. F.; Yin, X. A.

2014-05-01

136

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

PubMed

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

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

2008-03-01

137

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

PubMed

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

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

2014-11-01

138

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

SciTech Connect

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

Matsumura, Yukihiko; Nuessle, F.W.; Antal, M.J. Jr. [Univ. of Hawaii at Manoa, Honolulu, HI (United States)

1996-12-31

139

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

Microsoft Academic Search

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

Haruo Shindo

1991-01-01

140

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

Microsoft Academic Search

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

Todd E. Dawson

1993-01-01

141

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

E-print Network

for harvesting most of the soil water, which then flows within the plant vascular system up to the leaves whereOnset of water stress, hysteresis in plant conductance, and hydraulic lift: Scaling soil water] Estimation of water uptake by plants and subsequent water stress are complicated by the need to resolve

Katul, Gabriel

142

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

SciTech Connect

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

Matsumura, Yukihiko; Nuessle, F.W.; Antal, M.J. Jr. [Univ. of Hawaii at Manoa, Honolulu, HI (United States)

1996-10-01

143

Silicon Improves Water Use Efficiency in Maize Plants  

Microsoft Academic Search

The influence of silicon (Si) on water use efficiency (WUE) in maize plants (Zea mays L. cv. Nongda108) was investigated and the results showed that plants treated with 2 mmol L silicic acid (Si) had 20% higher WUE than that of plants without Si application. The WUE was increased up to 35% when the plants were exposed to water stress and this

Xiaopeng Gao; Chunqin Zou; Lijun Wang; Fusuo Zhang

2005-01-01

144

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

E-print Network

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

Vallino, Joseph J.

145

The effect of salinity on plant available water  

Microsoft Academic Search

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,

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

146

Performance Evaluation of a Water Treatment Plant (Case Study)  

Microsoft Academic Search

For providing continuous and good quality of water to all the regions in Maharashtra through out the year, Govt. of Maharashtra has constructed new water treatment plants during the past few years. Performance of these plants is an essential parameter to be monitored and evaluated for the better understanding of design and operating difficulties in water treatment plants. The conclusions

A. N. Burile; P. B. Nagarnaik

2010-01-01

147

Synergistic effect of plasmacatalyst and ozone in a pulsed corona discharge reactor on the decomposition of organic pollutants in water  

NASA Astrophysics Data System (ADS)

Plasmacatalytic effects of alpha-alumina, gamma-alumina, and silica gel in a pulsed corona discharge (PCD) reactor on the decomposition of aqueous methylene blue are described. Methylene blue concentration in the effluent was reduced to 23% of the inlet concentration by PCDs in water. Under the same experimental conditions, addition of alpha-alumina further reduced it to 8%, gamma-alumina to 4%, and silica gel to below the detection limits. PCDs with silica gel were run for >100 h in a continuous flow reactor and methylene blue in the effluent remained below the detection limit. A hybrid system of plasmacatalysis and ozonation is also described. Phenol concentration in the effluent was reduced to 84% of the inlet concentration by PCDs in water. Under the same experimental conditions, addition of either silica gel or ozone further reduced it to around 35%, and simultaneous addition of silica gel and ozone to 14% of inlet concentration. Decolourization of pre-adsorbed methylene blue on silica gel has been demonstrated. Adsorption and stabilization of the chemically active species on silica gel was indicated by experimental evidence. A significant improvement in the rate of decomposition of organic pollutants in water has been realized by hybridizing plasmacatalysis and ozonation in a PCD reactor.

Arif Malik, Muhammad

2003-11-01

148

Optimization of Energy and Water Consumption in Cornbased Ethanol Plants  

E-print Network

and water consumption in corn­based ethanol plants. The goal is to reduce the freshwater consumption and waste water discharge. We consider the corn-based ethanol plant reported in Karuppiah et al. (2008 water consumption. As a result, freshwater use is reduced to 1.17 gal water /gal ethanol, revealing

Grossmann, Ignacio E.

149

Estimating winter wheat plant water content using red edge parameters  

Microsoft Academic Search

Remote sensing of plant water content is difficult because the absorption band sensitive to foliar liquid water is also sensitive to the atmospheric vapour. A method using non-water-absorption spectral parameters to evaluate plant water content (PWC) would be valuable. In our experiment, canopy spectra of 48 winter wheat treatments with different varieties, different fertilization and irrigation levels were measured by

Liangyun Liu; Jihua Wang; Wenjiang Huang; Chunjiang Zhao; Bing Zhang; Qingxi Tong

2004-01-01

150

RECIRCULATION PROCESS OF DEMINERALIZATION WATER TREATMENT PLANT TO REDUCE CONDUCTIVITY LEVEL OF WATER  

E-print Network

Demineralization Water Treatment Plant serves to treat water that has been filtered at the Water Treatment Plant to be "good quality water " with the process of reverse osmosis. The initial design of Demineralization Water Treatment Plant in Pemaron – Bali Gas Turbine is to produce water that have conductivity level in 15 microsimens / cm, which is used for gas turbine cooling water system. At the moment we are planning to install Hydrogen Plant, it turns out this equipment takes raw water with a maximum conductivity of 5 microsimens / cm. So the product of Demineralization Water Treatment Plant is unable. Do a little innovation in production process of Demineralization Water Treatment Plant, namely recirculation, so that it can reduce the value conductivity to below 5 microsimens / cm. From result of laboratory test, it can be concluded that conductivity water after recirculation process is 2 microsimens / cm, thus meet requirement and can be used as raw water for Hydrogen Plant

Kukuh Pambudi; Widi Nurcahyo; K. Adi Dharma; W Tantrawan

151

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

Microsoft Academic Search

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

M. K. Chaturvedi; J. K. Bassin

2010-01-01

152

Decomposition analysis of water footprint changes in a water-limited river basin: a case study of the Haihe River Basin, China  

NASA Astrophysics Data System (ADS)

Decomposition analysis of water footprint (WF) changes, or assessing the changes in WF and identifying the contributions of factors leading to the changes, is important to water resource management. However, conventional studies focus on WF from the perspective of administrative region rather than river basin. Decomposition analysis of WF changes from the perspective of the river basin is more scientific. To address this perspective, we built a framework in which the input-output (IO) model and the Structural Decomposition Analysis (SDA) model for WF could be implemented in a river basin by computing IO data for the river basin with the Generating Regional IO Tables (GRIT) method. This framework is illustrated in the Haihe River Basin (HRB), which is a typical water-limited river basin. It shows that the total WF in the HRB increased from 4.3 × 1010 m3 in 2002 to 5.6 × 1010 m3 in 2007, and the agriculture sector makes the dominant contribution to the increase. Both the WF of domestic products (internal) and the WF of imported products (external) increased, and the proportion of external WF rose from 29.1% to 34.4%. The technological effect was the dominant contributor to offsetting the increase of WF; however, the growth of WF caused by the economic structural effect and the scale effect was greater, so the total WF increased. This study provides insights about water challenges in the HRB and proposes possible strategies for the future, and serves as a reference for WF management and policy making in other water-limited river basins.

Zhi, Y.; Yang, Z. F.; Yin, X. A.

2013-12-01

153

A theoretical study of water adsorption and decomposition on low-index spinel ZnGa2O4 surfaces: correlation between surface structure and photocatalytic properties.  

PubMed

Water adsorption and decomposition on stoichiometrically perfect and oxygen vacancy containing ZnGa2O4 (100), (110), and (111) surfaces were investigated through periodic density functional theory (DFT) calculations. The results demonstrated that water adsorption and decomposition are surface-structure-sensitive processes. On a stoichiometrically perfect surface, the most stable molecular adsorption that could take place involved the generation of hydrogen bonds. For dissociative adsorption, the adsorption energy of the (111) surface was more than 4 times the energies of the other two surfaces, indicating it to be the best surface for water decomposition. A detailed comparison of these three surfaces showed that the primary reason for this observation was the special electronic state of the (111) surface. When water dissociated on the (111) surface, the special Ga3c-4s and 4p hybridization states at the Fermi level had an obvious downshift to the lower energies. This large energy gain greatly promoted the dissociation of water. Because the generation of O(3c) vacancy defects on the (100) and (110) surfaces could increase the stability of the dissociative adsorption states with few changes to the energy barrier, this type of defect would make the decomposition of water molecules more favorable. However, for the (111) surface, the generation of vacancy defects could decrease the stability of the dissociative adsorption states and significantly increase their energy barriers. Therefore, the decomposition of water molecules on the oxygen vacancy defective (111) surface would be less favorable than the perfect (111) surface. These findings on the decomposition of H2O on the ZnGa2O4 surfaces can be used toward the synthesis of water-splitting catalysts. PMID:23682995

Jia, Chuanyi; Fan, Weiliu; Yang, Fei; Zhao, Xian; Sun, Honggang; Li, Pan; Liu, Li

2013-06-11

154

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

155

BARIUM AND RADIUM IN WATER TREATMENT PLANT WASTES  

EPA Science Inventory

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

156

The importance of native and exotic plant identity and dominance on decomposition patterns in mountain woodlands of central Argentina  

NASA Astrophysics Data System (ADS)

Exotic species can have a strong influence on ecosystem processes, especially when exotic invaders differ from natives in key morpho-functional features. We explored whether exotic species, especially those forming monospecific patches in Chaco montane woodlands, differ from natives in leaf attributes and decomposability. We then evaluated how exotic monospecific patches in that region alter litter decomposability, by weighting leaf trait values and decomposability by species abundance in the communities. In general, native and exotic species from Córdoba Chaco montane woodlands did not differ in leaf attributes (specific leaf area, leaf toughness, and leaf water content), or decomposability. Because of similar trait values and decomposability, we expected to find no differences in litter decomposability between plots dominated by exotic species and those of Native woodland. However, individual species decomposability weighted by species abundance in the communities showed that litter from exotic monospecific plots had slower decomposition than native ones. This pattern was confirmed by the higher decomposability and higher quality of the naturally mixed litter collected from native plots, compared to those collected from exotic plots. Despite the general similarities between most native and exotic species inhabiting Chaco montane woodlands, the overwhelming dominance of some exotic invaders in monospecific stands (and the consequent weight of their attributes on the litter each woodland produces) might be driving differences in decomposition patterns between woodland types. Our results indicate that when estimating the impact of exotic species on ecosystem processes, we should include their relative abundance in the community, as well as the relevance of the traits influencing those processes. Otherwise, we may draw erroneous conclusions.

Furey, Carolina; Tecco, Paula A.; Perez-Harguindeguy, Natalia; Giorgis, Melisa A.; Grossi, Mariana

2014-01-01

157

Water quality transformations during soil aquifer treatment at the Mesa Northwest Water Reclamation Plant, USA  

Microsoft Academic Search

Water quality transformations during soil aquifer treatment at the Mesa Northwest Water Reclamation Plant (NWWRP) were evaluated by sampling a network of groundwater monitoring wells located within the reclaimed water plume. The Mesa Northwest Water Reclamation Plant has used soil aquifer treatment (SAT) since it began operation in 1990 and the recovery of reclaimed water from the impacted groundwater has

P. Fox; K. Narayanaswamy; A. Gen; J. E. Drewes

158

Response of plants to CO 2 under water limited conditions  

Microsoft Academic Search

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

J. I. L. Morison; H. Lambers

1993-01-01

159

Metabolic responses of mesophytes to plant water deficits  

SciTech Connect

The metabolic responses of mesophytic plant to dehydration are surveyed and discussed. Whole-plant water relations, variations in CO/sub 2/, 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.

Hanson, A.D.; Hitz, W.D.

1982-01-01

160

Optimal design of an electrodialysis brackish water desalination plant  

Microsoft Academic Search

This paper considers the optimal design and operation of electrodialysis (ED) desalination plants. In general an ED plant aims to produce potable water from a high salinity source, like brackish water or high salinity water. The system is modelled mathematically as mixed-integer non-linear programming (MINLP) optimization problem, determining the number of desalination stages, the membrane area, the total required energy

Panagiotis Tsiakis; Lazaros G. Papageorgiou

2005-01-01

161

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

SciTech Connect

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

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

2007-09-17

162

Arbuscular mycorrhizae and soil\\/plant water relations  

Microsoft Academic Search

Augé, R. M. 2004. Arbuscular mycorrhizae and soil\\/plant water relations. Can. J. Soil Sci. 84: 373-381. The water relations of arbuscular mycorrhizal (AM) plants have been compared often. However, virtually nothing is known about the comparative water relations of AM and nonAM soils or about the relative influence of AM colonization of soil vs. AM colonization of plants on host

Robert M. Augé

163

Stable isotope composition of water in desert plants  

Microsoft Academic Search

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

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

2007-01-01

164

DECOMPOSITION AND REGENERATION OF NITROGENOUS ORGANIC MATTER IN SEA WATER.* VI. THE EFFECT OF ENZYME POISONS  

Microsoft Academic Search

When organic matter, in the form of natural marine plankton, is allowed to de compose in sea water in the dark under laboratory conditions ammonia is first found in the water, followed by nitrite, and later by nitrate, in amounts corresponding to the nitrogen which disappears from the suspended particulate matter. When, in the last stage, the water is inoculated

NORRIS W. RAKESTRAW; THEODOR VON BRAND

165

Detailed modeling of the evaporation and thermal decomposition of urea-water-solution in SCR systems  

E-print Network

-water-solution (UWS) is sprayed into the hot engine exhaust upstream of the SCR catalyst. It is commonly believed of urea concentration inside the droplet during the evaporation process. The effects of solute droplets (composed of water and zirconium acetate) axially injected into plasma. As water evaporates

Boyer, Edmond

166

Carbon Assimilation Pathways, Water Relationships and Plant Ecology.  

ERIC Educational Resources Information Center

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

Etherington, John R.

1988-01-01

167

Mechanistic insights into the dissociation and decomposition of carbonic acid in water via the hydroxide route: an ab initio metadynamics study.  

PubMed

The dissociation and decomposition of carbonic acid (H2CO3) in water are important reactions in the pH regulation in blood, CO2 transport in biological systems, and the global carbon cycle. H2CO3 is known to have three conformers [cis-cis (CC), cis-trans (CT), and trans-trans (TT)], but their individual reaction dynamics in water has not been probed experimentally. In this paper, we have investigated the energetics and mechanisms of the conformational changes, dissociation (H2CO3 -->/<-- HCO3(-) + H(+)), and decomposition via the hydroxide route (HCO3(-) --> CO2+OH(-)) of all three conformers of H2CO3 in water using Car-Parrinello molecular dynamics (CPMD) in conjunction with metadynamics. It was found that, unlike in the gas phase, the interconversion between the various conformers occurs via two different pathways, one involving a change in one of the two dihedral angles (O=C-O-H) and the other a proton transfer through a hydrogen-bond wire. The free energy barriers/changes for the various conformational changes via the first pathway were calculated and contrasted with the previously calculated values for the gas phase. The CT and TT conformers were found to undergo decomposition in water via a two-step process: first, the dissociation and then the decomposition of HCO3(-) into CO2 and OH(-). The CC conformer does not directly decompose but first undergoes a conformational change to CT or TT prior to decomposition. This is in contrast with the concerted mechanism proposed for the gas phase, which involves a dehydroxylation of one of the OH groups and a simultaneous deprotonation of the other OH group to yield CO2 and H2O. The dissociation in water was seen to involve the repeated formation and breakage of a hydrogen-bond wire with neighboring water molecules, whereas the decomposition is initiated by the diffusion of H(+) away from HCO3(-); this decomposition mechanism differs from that proposed for the water route dehydration (HCO3(-) + H3O(+) --> CO2 + H2O), which involves the participation of a nearbyH3O(+) ion.Our calculated pKa values and decomposition free energy barriers for the CT and TT conformers are consistent with the overall experimental values of 3.45 and 22.28 kcal/mol, respectively, suggesting that the dynamics of the various conformers should be taken into account for a better understanding of aqueous H2CO3 chemistry. PMID:22053746

Galib, Mirza; Hanna, Gabriel

2011-12-22

168

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

PubMed Central

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

Zhu, Jianxiao; Yang, Wanqin; He, Xinhua

2013-01-01

169

AQUATIC PLANTS FOR BIOREMEDIATION OF WASTE WATER  

Microsoft Academic Search

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

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

170

Plant Anatomy and Reproduction Plants have three main parts Absorb water  

E-print Network

; it usually leaves via the stoma on the leaf underside. After the water evaporates it leaves a "space" to be filled, which is done by water in the xylem tubes. This leaves a "space" in the xylem tube, which1 Plant Anatomy and Reproduction Plants have three main parts Absorb water and nutrients support

Brown, Christopher A.

171

RO membrane autopsy of Zarzis brackish water desalination plant  

Microsoft Academic Search

Tunisia, located in a semi-arid zone, has limited water resources. The shortage of good water quality in particular at the south regions required a brackish water desalination to supply these regions with potable water. Zarzis desalination plant, working since 1999, has revealed difficulties related to the loss of membrane performances. In the aim to determine the reason of membrane fouling,

Mohamed Karime; S. Bouguecha; B. Hamrouni

2008-01-01

172

Agar-Block Microcosms for Controlled Plant Tissue Decomposition by Aerobic Fungi  

PubMed Central

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

Schilling, Jonathan S.

2011-01-01

173

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

PubMed

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

Schilling, Jonathan S; Jacobson, K Brook

2011-01-01

174

A micropump based on water potential difference in plants  

Microsoft Academic Search

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

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

175

Optimization of a Chilled Water Plant Using a Forward Plant Model  

E-print Network

This paper introduces a forward chilled water plant model to optimize the setpoints of continuous controlled variables in a chiller plant without storage and controlled by supervisory control. It can also be used to estimate the savings potential...

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

2010-01-01

176

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

NASA Astrophysics Data System (ADS)

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.

Katayanagi, Hitoshi; Miki, Norihisa

177

Air-cooled condensers eliminate plant water use  

Microsoft Academic Search

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

W. Wurtz; R. Peltier

2008-01-01

178

Optimization of Water Consumption in Second Generation Bioethanol Plants  

E-print Network

1 Optimization of Water Consumption in Second Generation Bioethanol Plants Mariano Martína optimization of second generation bioethanol production plants from lignocellulosic switchgrass when using. The design of water networks can be performed using two different approaches: (a) conceptual engineering app

Grossmann, Ignacio E.

179

BENEFICIAL DISPOSAL OF WATER PURIFICATION PLANT SLUDGES IN WASTEWATER TREATMENT  

EPA Science Inventory

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

180

Air-cooled condensers eliminate plant water use  

SciTech Connect

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

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

2008-09-15

181

Foothills: A State-of-the-Art Water Treatment Plant  

Microsoft Academic Search

After three years of operation, the showcase Foothills water treatment plant, serving the base needs of the Denver, Colo., metropolitan area, has been performing at, or above, expectations. Taking hydraulic advantage of its location above the city, the plant's pumping costs are minimal and the plant's hydro turbine generates enough power to operate the facilities and sell excess electricity. A

Robert K. Weir; Robert L. Chapman

1987-01-01

182

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 ...

183

Water Conservation with Urban Landscape Plants  

E-print Network

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...

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

184

Plant experience with temporary reverse osmosis makeup water systems  

SciTech Connect

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.

Polidoroff, C.

1986-01-01

185

Regularized Statistical Material Decomposition in Medical Imaging  

E-print Network

. . . . . . . . . . . . . . . . . . . . . . . . . 27 5. Water-Fat Decomposition from MR k-space Data using Regularized Field Map . . . . . . . . . . . . . . . . . . 12 4. Water-Fat Decomposition with Regularized Field Map Estimation . . 14 4.1 Introduction. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.1 Water-Fat Decomposition

Fessler, Jeffrey A.

186

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

USGS Publications Warehouse

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

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

1933-01-01

187

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

Microsoft Academic Search

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

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

2003-01-01

188

Decomposition of river water nitrate time-series — comparing agricultural and urban signals  

Microsoft Academic Search

This article explores the combined effects of agricultural and urban influences on the time-series of the nitrate concentration in river water. The temporal and spatial variation of the river water signal for nitrate are examined using time-series analysis. The catchment chosen for this study was the River Wansbeck in south-east Northumberland where a distinct agricultural to urban gradient exists down

F Worrall; T. P Burt

1998-01-01

189

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

PubMed

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

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

2012-11-30

190

Quantifying root water extraction by rangeland plants through soil water modeling  

Microsoft Academic Search

We used soil water modeling as a tool to quantify water use of non-cultivated plant communities based on easily measured field\\u000a data of soil water contents, soil hydraulic properties, and leaf area index. The model was applied in the mixed-grass prairie,\\u000a considering a dynamic and non-uniform root distribution, the effect of soil water stress on plant water uptake, as well

Xuejun Dong; Bob D. Patton; Anne C. Nyren; Paul E. Nyren; Lyle D. Prunty

2010-01-01

191

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

E-print Network

with and without the influence of atmospheric carbon dioxide based upon Buch's tables on the carbon dioxide and boric acid system in sea water are compared with exper- imental data obtained by the method of Mitchell and Rakestraw(1933) and Stoddard (1952... Mixtures of weak acids and their salts or of weak bases and their sa3ts are called buffer solutions, since they resist a change in pH upon addit1on oi' sli~ht amounts oi' acid or bases (Kolthoff', 1949). Sea water contairs carbonic and boric acids...

Park, Kilho

2012-06-07

192

ENERGY AND WATER OPTIMIZATION IN BIOFUEL PLANTS Ignacio E. Grossmann*  

E-print Network

1 ENERGY AND WATER OPTIMIZATION IN BIOFUEL PLANTS Ignacio E. Grossmann* , Mariano Martín Center amount of water consumption [18]. 2nd generation biofuels try to overcome these problems by using non to develop sustainable biofuel processes by means of a two-stage approach. 2 STRATEGY FOR ENERGY AND WATER

Grossmann, Ignacio E.

193

Improving Water Quality by Coordinating Industries Schedules and Treatment Plants  

Microsoft Academic Search

Having a proper waste water treatment system is crucial for making a good use of water resources. Current regulations enforce some restrictions to the industries producing waste, according to the capacities of waste water treatment plants. However, these are usually not sufficient to ensure that these capacities are not exceeded. In this paper we present a co- ordination system that

Víctor Muñoz; Javier Murillo; Dídac Busquets; Beatriz López

2007-01-01

194

Water treatment plant intelligent monitoring in large gas refinery  

Microsoft Academic Search

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

Amir Firoozshahi; Li Mengyang

2010-01-01

195

Temperature and water relation patterns in subalpine understory plants  

Microsoft Academic Search

The daily temperature and water relations of 7 perennial subalpine, understory species (1 shrub, 1 subshrub, 5 herbs) were compared in the Rocky Mountains of southeastern Wyoming with an emphasis on the effects of natural sun and shade exposure. Field measurements of rainfall; leaf, air, and soil temperatures; stomatal conductance to water vapor diffusion; and plant and soil water potentials

W. K. Smith

1981-01-01

196

Hydraulic redistribution may stimulate decomposition  

Microsoft Academic Search

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

Zachary T. Aanderud; James H. Richards

2009-01-01

197

Using biochemically purified water at coke plants  

Microsoft Academic Search

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

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

2008-01-01

198

LU Decomposition  

NSDL National Science Digital Library

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

Fitchett, Stephanie; Smith, David

2010-06-07

199

Water recovery using waste heat from coal fired power plants.  

SciTech Connect

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.

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

2011-01-01

200

Use of reclaimed water for power plant cooling.  

SciTech Connect

Freshwater demands are steadily increasing throughout the United States. As its population increases, more water is needed for domestic use (drinking, cooking, cleaning, etc.) and to supply power and food. In arid parts of the country, existing freshwater supplies are not able to meet the increasing demands for water. New water users are often forced to look to alternative sources of water to meet their needs. Over the past few years, utilities in many locations, including parts of the country not traditionally water-poor (e.g., Georgia, Maryland, Massachusetts, New York, and North Carolina) have needed to reevaluate the availability of water to meet their cooling needs. This trend will only become more extreme with time. Other trends are likely to increase pressure on freshwater supplies, too. For example, as populations increase, they will require more food. This in turn will likely increase demands for water by the agricultural sector. Another example is the recent increased interest in producing biofuels. Additional water will be required to grow more crops to serve as the raw materials for biofuels and to process the raw materials into biofuels. This report provides information about an opportunity to reuse an abundant water source -- treated municipal wastewater, also known as 'reclaimed water' -- for cooling and process water in electric generating facilities. The report was funded by the U.S. Department of Energy's (DOE's) National Energy Technology Laboratory (NETL) Innovations for Existing Plants research program (Feeley 2005). This program initiated an energy-water research effort in 2003 that includes the availability and use of 'nontraditional sources' of water for use at power plants. This report represents a unique reference for information on the use of reclaimed water for power plant cooling. In particular, the database of reclaimed water user facilities described in Chapter 2 is the first comprehensive national effort to identify and catalog those plants that are using reclaimed water for cooling.

Veil, J. A.; Environmental Science Division

2007-10-16

201

Semipermeable Membrane System for Subjecting Plants to Water Stress  

PubMed Central

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-vermiculite mass, and then placed into nutrient solutions to which various amounts of polyethylene glycol (PEG) 20M were added to control solution water potential. The membrane (Spectrapor 1) had a minimum molecular weight cutoff that excluded the PEG 20M. The plants equilibrated with the nutrient solution within 1 to 4 days, and exhibited normal diurnal water relations. Use of the semipermeable membrane system to induce water stress reduces many of the problems associated with hydroponic media. PMID:16660044

Tingey, David T.; Stockwell, Cynthia

1977-01-01

202

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

Federal Register 2010, 2011, 2012, 2013

...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...

2013-06-12

203

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

Federal Register 2010, 2011, 2012, 2013

...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...

2012-12-07

204

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

205

COMPUTER COST MODELS FOR POTABLE WATER TREATMENT PLANTS  

EPA Science Inventory

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

206

MICROORGANISMS AND HIGHER PLANTS FOR WASTE WATER TREATMENT  

EPA Science Inventory

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

207

Water Pinch Success Story at Solutia's Krummrich Plant  

E-print Network

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...

Kumana, J. D.

208

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

EPA Science Inventory

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

209

Optimisation of complex water supply systems with water quality, hydraulic and treatment plant aspects  

Microsoft Academic Search

A model for optimal operation of a complex water supply system for drinking water and with water quality, hydraulic and desalination treatment plants developed by Cohen and others has been applied to a realistic regional network, in which water quality is defined by salinity, magnesium and sulphur. The model considers the hydraulics of the network, including pump stations, boosters and

Dani Cohen; Uri Shamir; Gideon Sinai

2009-01-01

210

Cogen/chilled-water plant heats, cools, electrifies campus  

SciTech Connect

This article describes replacement of the University of California at Los Angeles' aging boiler and refrigeration equipment with a central chiller/combined-cycle cogeneration plant. The topics of the article include the work scope, the chilled water plant including absorption and steam turbine driven centrifugal chillers, and the cogeneration plant including two packaged combustion turbines, two heat-recovery steam generators and one steam turbogenerator.

Johnson, D.N. (Univ. of California, Los Angeles (United States)); Bakker, V.

1993-04-01

211

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

212

DECOMPOSITION IN FRESHWATER ECOSYSTEMS  

Microsoft Academic Search

This review examines the sources and composition of organic matter and the decomposition of particulate and dissolved organic matter (POM and DOM) in freshwater ecosystems. The main points to emerge from the review are listed below.1. Terrestrial plant material is an important source of allochthonous POM in lotlc systems.2. In lentic systems important autochthonous sources of DOM are the algae

R. D. Robarts

1986-01-01

213

Global distribution of plant-extractable water capacity of soil  

USGS Publications Warehouse

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.

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

1996-01-01

214

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

Microsoft Academic Search

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

Walter Schüssler

1998-01-01

215

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

PubMed

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

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

2012-03-01

216

IStreambank Plants Vital to Water Quality  

E-print Network

streambanks sends sediment down to clog drinking water reservoirs, reduce fish populations, and block hydro electric dams, one of the region's main sources of power. "Before we can reduce this type of damage, we

217

Plants reverse warming effect on ecosystem water balance  

E-print Network

that global warming may increase aridity in water- limited ecosystems by accelerating evapotranspiration. WePlants reverse warming effect on ecosystem water balance Erika S. Zavaleta* , Brian D. Thomas show that interactions between warming and the dominant biota in a grassland ecosystem produced

Zavaleta, Erika

218

ARSENIC REMOVAL FROM DRINKING WATER BY IRON REMOVAL PLANTS  

EPA Science Inventory

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

219

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

E-print Network

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

Migliaccio, Kati White

220

Investigating water transport through the xylem network in vascular plants.  

PubMed

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

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

2014-04-01

221

Plants for water recycling, oxygen regeneration and food production  

NASA Technical Reports Server (NTRS)

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.

Bubenheim, D. L.

1991-01-01

222

USE of mine pool water for power plant cooling.  

SciTech Connect

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

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

2006-11-27

223

Will rising atmospheric CO 2 affect leaf litter quality and in situ decomposition rates in native plant communities?  

Microsoft Academic Search

Though field data for naturally senesced leaf litter are rare, it is commonly assumed that rising atmospheric CO2 concentrations will reduce leaf litter quality and decomposition rates in terrestrial ecosystems and that this will lead\\u000a to decreased rates of nutrient cycling and increased carbon sequestration in native ecosystems. We generally found that the\\u000a quality of?naturally senesced leaf litter (i.e. concentrations

G. Hirschel; C. Körner

1997-01-01

224

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

PubMed Central

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

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

2013-01-01

225

Improving the water consumption system in industrial plants  

Microsoft Academic Search

The annual demand for watet by plants of this branch exceeds 450 million m 3. And, although during the last ten years the specific water demand has been reduced by 10-15%, the total amount of water needed has remained high, in connection with the considerable rise is man-made fibre production. Further assurance of water for the man-made fibre industry is

V. V. Shibalina; V. V. Shmatova

1989-01-01

226

Water vulnerabilities for existing coal-fired power plants.  

SciTech Connect

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

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

2010-08-19

227

Water transport in plant cuticles: an update  

Microsoft Academic Search

The scale, mechanism, and physiological importance of cuticular transpiration were last reviewed in this journal 5 and 10 years ago. Progress in our basic understanding of the underlying processes and their physiological and structural determinants has re- mained frustratingly slow ever since. There have been major advances in the quantification of cuticular water permeability of stomata-bearing leaf and fruit surfaces

Gerhard Kerstiens

2006-01-01

228

Wetlands: Water, Wildlife, Plants, and People.  

ERIC Educational Resources Information Center

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

Vandas, Steve

1992-01-01

229

Does pre-dawn water potential reflect conditions of equilibrium in plant and soil water status?  

NASA Astrophysics Data System (ADS)

Variation in base water potential ( ?b, a daily maximum level of plant water potential, which is presumed to correspond to the equilibrium between soil and plant water potentials) was examined in shoots of Picea abies and Vaccinium myrtillus with respect to soil (available water storage, water potential, temperature) and atmospheric (temperature, relative humidity, vapour pressure deficit) conditions. The available soil water storage (W tr) accounted for 77% of the dynamics of ?b, while the influence of atmospheric factors became evident under high evaporative demand. ?b was not always observable immediately before dawn, but on 30% of observation days, the recovery continued up to an hour or two after dawn. Full equilibrium between soil and plant water potentials in P. abies in northern conditions is rather improbable by dawn in summer-time, because of the shortness of the dark period and probable night-time transpiration in the case of high atmospheric vapour pressure deficit.

Sellin, Arne

1999-02-01

230

Plants Clean Air and Water for Indoor Environments  

NASA Technical Reports Server (NTRS)

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

2007-01-01

231

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

Microsoft Academic Search

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

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

2011-01-01

232

Decomposition techniques  

USGS Publications Warehouse

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.

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

1992-01-01

233

Warm water aquaculture using waste heat and water from zero discharge power plants in the Great Basin  

Microsoft Academic Search

Two series of experiments were completed to determine (a) toxicity of waste water from power plants on warm water fish and (b) multiple use of waste heat and water for aquatic animal and plant production. All three types of waste water from a typical coal-fired power plant are acceptable for growing catfish and tilapia following aeration. This growth was compared

R. A. Heckmann; R. N. Winget; R. C. Infanger; R. W. Mickelsen; J. M. Hendersen

1984-01-01

234

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

SciTech Connect

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

Ehleringer, J.R.

1992-11-17

235

Water use, productivity and interactions among desert plants  

SciTech Connect

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

Ehleringer, J.R.

1992-11-17

236

Animal or Plant: Which Is the Better Fog Water Collector?  

PubMed Central

Occasional fog is a critical water source utilised by plants and animals in the Namib Desert. Fog basking beetles (Onymacris unguicularis, Tenebrionidae) and Namib dune bushman grass (Stipagrostris sabulicola, Poaceae) collect water directly from the fog. While the beetles position themselves optimally for fog water collection on dune ridges, the grass occurs predominantly at the dune base where less fog water is available. Differences in the fog-water collecting abilities in animals and plants have never been addressed. Here we place beetles and grass side-by-side in a fog chamber and measure the amount of water they collect over time. Based on the accumulated amount of water over a two hour period, grass is the better fog collector. However, in contrast to the episodic cascading water run-off from the grass, the beetles obtain water in a steady flow from their elytra. This steady trickle from the beetles' elytra to their mouth could ensure that even short periods of fog basking – while exposed to predators – will yield water. Up to now there is no indication of specialised surface properties on the grass leafs, but the steady run-off from the beetles could point to specific property adaptations of their elytra surface. PMID:22509331

N?rgaard, Thomas; Ebner, Martin; Dacke, Marie

2012-01-01

237

Macroscopic modeling of plant water uptake: soil and root resistances  

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

238

Plant Response to Differential Soil Water Content and Salinity  

NASA Astrophysics Data System (ADS)

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.

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

2011-12-01

239

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

Microsoft Academic Search

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

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

2001-01-01

240

Filtration demonstration plant as reverse osmosis pretreatment in an industrial water treatment plant  

Microsoft Academic Search

Reverse osmosis (RO) has emerged as an alternative treatment in industrial water production. However, RO systems need suitable pretreatment to avoid membranes fouling. A demonstration study was conducted to assess improvements to RO pretreatment in the water treatment plant of a steel factory. Various pretreatment options, resulting from the combination of the existing treatment with different filtration stages, were tested.

Noelia Quevedo; Joan Sanz; Amaya Lobo; Javier Temprano; Iñaki Tejero

241

Metabolites from soil bacteria affect plant water relations  

Microsoft Academic Search

Water-soluble compounds move naturally in soil moisture toward roots of transpiring plants. To test for effects of rhizosphere food-web molecules on plants, low concentrations of common microbial products were supplied to bean (Phaseolus vulgaris L.) roots. Stomatal conductance and transpiration increased significantly (+20 to +30%, P ? 0.05) 42 h after 10 nM homoserine lactone (HL) was supplied to roots. Because transpiration

2003-01-01

242

Water, plants, and early human habitats in eastern Africa  

PubMed Central

Water and its influence on plants likely exerted strong adaptive pressures in human evolution. Understanding relationships among water, plants, and early humans is limited both by incomplete terrestrial records of environmental change and by indirect proxy data for water availability. Here we present a continuous record of stable hydrogen-isotope compositions (expressed as ?D values) for lipid biomarkers preserved in lake sediments from an early Pleistocene archaeological site in eastern Africa—Olduvai Gorge. We convert sedimentary leaf- and algal-lipid ?D values into estimates for ancient source-water ?D values by accounting for biochemical, physiological, and environmental influences on isotopic fractionation via published water–lipid enrichment factors for living plants, algae, and recent sediments. Reconstructed precipitation and lake-water ?D values, respectively, are consistent with modern isotopic hydrology and reveal that dramatic fluctuations in water availability accompanied ecosystem changes. Drier conditions, indicated by less negative ?D values, occur in association with stable carbon-isotopic evidence for open, C4-dominated grassland ecosystems. Wetter conditions, indicated by lower ?D values, are associated with expanded woody cover across the ancient landscape. Estimates for ancient precipitation amounts, based on reconstructed precipitation ?D values, range between approximately 250 and 700 mm·y?1 and are consistent with modern precipitation data for eastern Africa. We conclude that freshwater availability exerted a substantial influence on eastern African ecosystems and, by extension, was central to early human proliferation during periods of rapid climate change. PMID:23267102

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

2013-01-01

243

Do rock fragments participate to plant water and mineral nutrition?  

NASA Astrophysics Data System (ADS)

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

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

2010-05-01

244

A one-dimensional model of water flow in soil-plant systems based on plant architecture  

Microsoft Academic Search

The estimation of root water uptake and water flow in plants is crucial to quantify transpiration and hence the water exchange\\u000a between land surface and atmosphere. In particular the soil water extraction by plant roots which provides the water supply\\u000a of plants is a highly dynamic and non-linear process interacting with soil transport processes that are mainly determined\\u000a by the

Michael Janott; Sebastian Gayler; Arthur Gessler; Mathieu Javaux; Christine Klier; Eckart Priesack

2011-01-01

245

Biogeochemistry of Decomposition and Detrital Processing  

NASA Astrophysics Data System (ADS)

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

Sanderman, J.; Amundson, R.

2003-12-01

246

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

NASA Astrophysics Data System (ADS)

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

Pichat, S.; Fekiacova, Z.

2013-12-01

247

Effects of water stress on male gametophyte development in plants  

Microsoft Academic Search

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

Hargurdeep S. Saini

1997-01-01

248

Long-term performance of an industrial water desalination plant  

Microsoft Academic Search

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

Nader Al-Bastaki; Abderrahim Abbas

2004-01-01

249

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

Microsoft Academic Search

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

Derek Wolf; Jeremy T. Lundholm

2008-01-01

250

Optimal plant water-use strategies under stochastic rainfall  

NASA Astrophysics Data System (ADS)

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

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

2014-07-01

251

Integrated operation of drinking water treatment plant at Amsterdam water supply  

Microsoft Academic Search

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

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

252

Mathematics for Water and Wastewater Treatment Plant Operators. Water and Wastewater Training Program.  

ERIC Educational Resources Information Center

This booklet is intended to aid the prospective waste treatment plant operator or drinking water plant operator in learning to solve mathematical problems, which is necessary for Class I certification. It deals with the basic mathematics which a Class I operator may require in accomplishing day-to-day tasks. The book also progresses into problems…

South Dakota Dept. of Environmental Protection, Pierre.

253

An Interpretation of Some Whole Plant Water Transport Phenomena  

PubMed Central

A treatment of water flow into and through plants to the evaporating surface of the leaves is presented. The model is driven by evaporation from the cell wall matrix of the leaves. The adsorptive and pressure components of the cell wall matric potential are analyzed and the continuity between the pressure component and the liquid tension in the xylem established. Continuity of these potential components allows linking of a root transport function, driven by the tension in the xylem, to the leaf water potential. The root component of the overall model allows for the solvent-solute interactions characteristic of a membrane-bound system and discussion of the interactions of environmental variables such as root temperature and soil water potentials. A partition function is developed from data in the literature which describes how water absorbed by the plant might be divided between transpiration and leaf growth over a range of leaf water potentials. Relationships between the overall system conductance and the conductance coefficients of the various plant parts (roots, xylem, leaf matrix) are established and the influence of each of these discussed. The whole plant flow model coupled to the partition function is used to simulate several possible relationships between leaf water potential and transpiration rate. The effects of changing some of the partition function coefficients, as well as the root medium water potential on these simulations is illustrated. In addition to the general usefulness of the model and its ability to describe a wide range of situations, we conclude that the relationships used, dealing with bulk fluid flow, diffusion, and solute transport, are adequate to describe the system and that analogically based theoretical systems, such as the Ohm's law analogy, probably ought to be abandoned for this purpose. PMID:16662912

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

1983-01-01

254

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

255

Treatment of waste water from marine products processing plants  

Microsoft Academic Search

Different types of pollutants produced as by?products in various marine product processing plants are described. A detailed discussion on the effects of these polluting materials on the environment follows. Various technologies available for treating waste water contaminated with the above are introduced. Methods are described for evaluating various processing methods and choosing a method that meets individual processing requirements based

Kazuo Sano

1988-01-01

256

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

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

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

257

Current focuses in woody plant water relations and drought resistance  

E-print Network

Current focuses in woody plant water relations and drought resistance T.M. Hinckley1 R. Ceulemans2, such as drought, affects physio- logical processes and is the result of one or a combination of environmental and experimental relevance. Drought stress may be induced by environmental (e.g., low precipitation, low humidity

Boyer, Edmond

258

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

Microsoft Academic Search

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

Aleksandra Kosti?-Pulek; Svetlana Popov

259

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...

260

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...

261

Dynamic modelling of water demand, water availability and adaptation strategies for power plants to global change  

Microsoft Academic Search

According to the latest IPCC reports, the frequency of hot and dry periods will increase in many regions of the world in the future. For power plant operators, the increasing possibility of water shortages is an important challenge that they have to face. Shortages of electricity due to water shortages could have an influence on industries as well as on

Hagen Koch; Stefan Vögele

2009-01-01

262

Heat and Mass Transfer in Quenching the Reaction of Thermal Decomposition of a Forest Combustible Material with a Group of Water Drops  

NASA Astrophysics Data System (ADS)

We have carried out computational investigations of the processes of heat and mass transfer in quenching the reaction of thermal decomposition of the typical forest combustible materials (birch leaves and pine and fir needles) with a group of water drops. It has been established that the termination time of pyrolysis is influenced by the integral parameter characterizing the relative position of drops and the temperature of the vapor-gas mixture over the forest combustible material. The thicknesses of layers providing termination of pyrolysis of evaporated liquid materials for a group of drops have been determined.

Kuznetsov, G. V.; Strizhak, P. A.

2014-05-01

263

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

E-print Network

-largest city in Texas and the #26;#19;th-largest in the United States,? Michelsen said. El Paso landscape perspective Researchers study water conservation, plant-tolerance, and water reuse 16 tx H2O Summer 2011 El Paso landscape perspective Continued... the sustainability of the region.? Home landscape water conservation Dr. Genhua Niu, associate professor at the El Paso center, focuses her research on identifying drought-, salt-, and heat-tolerant plants that are be#14;er suited for this environment. ?#29;ere...

Kalisek, Danielle

2011-01-01

264

Performance evaluation of water treatment ultrafiltration pilot plants treating algae-rich reservoir water  

Microsoft Academic Search

Three different water treatment ultrafiltration (UF) pilot plants were investigated to treat algae-rich reservoir water. Coagulation, coagulation–sedimentation and coagulation–sedimentation–filtration were applied prior to UF respectively. Based on the permeate water quality and the specific flux of UF, coagulation\\/settling process was selected as the best pretreatment method for UF membrane. Filter played a negative role in pretreatment for UF membrane fouling

Heng Liang; Weijia Gong; Guibai Li

2008-01-01

265

Study on the TOC concentration in raw water and HAAs in Tehran's water treatment plant outlet  

PubMed Central

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

2013-01-01

266

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

PubMed

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

Ghoochani, Mahboobeh; Rastkari, Noushin; Nabizadeh Nodehi, Ramin; Mahvi, Amir Hossein; Nasseri, Simin; Nazmara, Shahrokh

2013-01-01

267

Karst features and plant water sources in Yucatan, Mexico  

NASA Astrophysics Data System (ADS)

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.

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

2008-05-01

268

Developmental changes in plant resistance to water flow in Pisum sativum (L.)  

Microsoft Academic Search

Soil and plant resistance to water flow under field conditions in pea (Pisum sativum L.) plants were measured at six ages. Transpiration flux, leaf and soil water potentials were used to calculate the total resistance to water flow using the Ohm's law analogy. Plant resistance was estimated from the slope of the water potential difference (??) vs. transpiration (Q) relationship.

Celestino Ruggiero; Stefania De Pascale; Giovanna Angelino; Albino Maggio

2003-01-01

269

Diverting water at dams during construction of hydro plants  

SciTech Connect

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 dam. To do this, however, typically requires a temporary shutdown of the outlet works during construction. Since most dam owners are required to discharge a minimum flow of water through the outlet works to meet water quality standards, some type of temporary diversion scheme is essential. The Incorporated County of Los Alamos, New Mexico, was recently faced with this situation when constructing a hydroelectric project at an existing US Army Corps of Engineers' dam. The county hired Tudor Engineering Company in Oakland, California, to perform the design for the hydro project, including a water diversion system that temporarily conveyed reservoir discharges over the dam to the river downstream. The diversion was necessary so modifications could be made to the outlet works of the dam where the county was building its 13-MW plant. This system, comprised of pumps mounted on a floating barge in the reservoir, allowed the Corps of Engineers to maintain required instream flows while the outlet works were being modified.

Kneitz, P.R. (Tudor Engineering Company, Oakland, CA (United States))

1991-04-01

270

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

Microsoft Academic Search

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

M. Hangos

271

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

NASA Astrophysics Data System (ADS)

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.

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

2014-09-01

272

Warm water aquaculture using waste heat and water from zero discharge power plants in the Great Basin  

SciTech Connect

Two series of experiments were completed to determine (a) toxicity of waste water from power plants on warm water fish and (b) multiple use of waste heat and water for aquatic animal and plant production. All three types of waste water from a typical coal-fired power plant are acceptable for growing catfish and tilapia following aeration. This growth was compared with fish raised in spring water. Closed, recirculating polyculture systems using evaporation pond water operated efficiently for plant (duckweed) and animal (fish and freshwater prawns) production. Duckweed is an excellent supplement for fish feed. Tilapia and freshwater prawns grew rapidly in the tanks containing duckweed only. 10 references, 13 tables.

Heckmann, R.A.; Winget, R.N.; Infanger, R.C.; Mickelsen, R.W.; Hendersen, J.M.

1984-01-31

273

Significance of Plant Root Microorganisms in Reclaiming Water in CELSS  

NASA Technical Reports Server (NTRS)

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.

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

1996-01-01

274

Planted floating bed performance in treatment of eutrophic river water.  

PubMed

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

Bu, Faping; Xu, Xiaoyi

2013-11-01

275

Accident source terms for light-water nuclear power plants  

Microsoft Academic Search

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

Soffer

1993-01-01

276

Characteristics of RO foulants in a brackish water desalination plant  

Microsoft Academic Search

This study identified the membrane fouling of a two-stage RO process of the Bai-sha brackish water desalination plant facing serious fouling problems. Two membrane modules, one from each stage, were autopsied and diagnosed for the cause for the failure of the RO system. Different morphologies were exhibited on the fouled membrane. Results suggested that the fouling on the first-stage membrane

Hui Ling Yang; Chihpin Huang; Jill R. Pan

2008-01-01

277

Nitrogen Removal from Eutrophicated Water by Aquatic Plants  

Microsoft Academic Search

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

Olga Babourina; Zed Rengel

278

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

SciTech Connect

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

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

2008-01-01

279

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

PubMed

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

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

2014-01-01

280

Biotic vs. Abiotic Control of Decomposition: A Comparison of the Effects of Simulated Extinctions and Changes in Temperature  

PubMed Central

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

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

2014-01-01

281

Plant Responses of Drip Irrigated Trees to Climate and Water Stress  

E-print Network

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

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

282

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

Microsoft Academic Search

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

Henk Van As; Carel W. Windt

2008-01-01

283

Innovative Fresh Water Production Process for Fossil Fuel Plants  

SciTech Connect

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

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

2005-09-01

284

Temporal patterns of litter production by vascular plants and its decomposition rate in cut-over peatlands  

Microsoft Academic Search

Peatlands are an important carbon (C) store but many have been drained and damaged by mechanical harvesting. Little is known\\u000a about ecological processes on abandoned peatlands that have recolonized naturally nor the impact of plants on C balance of\\u000a these sites. Over the course of 13 months, we measured amounts of litter falling from three different species colonizing an\\u000a abandoned

Clare J. Trinder; Rebekka R. E. Artz; David Johnson

2008-01-01

285

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

PubMed Central

Spectral reflectance indices can be used to estimate the water status of plants in a rapid, non-destructive manner. Water spectral indices were measured on wheat under a range of water-deficit conditions in field-based yield trials to establish their relationship with water relations parameters as well as available volumetric soil water (AVSW) to indicate soil water extraction patterns. Three types of wheat germplasm were studied which showed a range of drought adaptation; near-isomorphic sister lines from an elite/elite cross, advanced breeding lines, and lines derived from interspecific hybridization with wild relatives (synthetic derivative lines). Five water spectral indices (one water index and four normalized water indices) based on near infrared wavelengths were determined under field conditions between the booting and grain-filling stages of crop development. Among all water spectral indices, one in particular, which was denominated as NWI-3, showed the most consistent associations with water relations parameters and demonstrated the strongest associations in all three germplasm sets. NWI-3 showed a strong linear relationship (r2 >0.6–0.8) with leaf water potential (?leaf) across a broad range of values (–2.0 to –4.0 MPa) that were determined by natural variation in the environment associated with intra- and inter-seasonal affects. Association observed between NWI-3 and canopy temperature (CT) was consistent with the idea that genotypes with a better hydration status have a larger water flux (increased stomatal conductance) during the day. NWI-3 was also related to soil water potential (?soil) and AVSW, indicating that drought-adapted lines could extract more water from deeper soil profiles to maintain favourable water relations. NWI-3 was sufficiently sensitive to detect genotypic differences (indicated by phenotypic and genetic correlations) in water status at the canopy and soil levels indicating its potential application in precision phenotyping. PMID:20639342

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

2010-01-01

286

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

Microsoft Academic Search

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

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

2006-01-01

287

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

Microsoft Academic Search

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

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

2002-01-01

288

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

289

Spatial and temporal variability of soil water in drylands: plant water potential as a diagnostic tool  

Microsoft Academic Search

Arid and semi-arid regions are characterized by low rainfall and high potential evaporative demand. Here, water is the major\\u000a limiting factor for plant growth and productivity. Soil and surface hydrology properties (e.g. field capacity, infiltration\\u000a rates) effectively control the water re-distribution in the ecosystem, a fact that is aggravated in arid environments. Information\\u000a of the spatial and temporal accessibility of

Maik Veste; Markus Staudinger; Manfred Küppers

2008-01-01

290

An ASAE/CSAE Meeting Presentation Paper Number: 043065 Estimating Water Stress in Plants Using  

E-print Network

An ASAE/CSAE Meeting Presentation Paper Number: 043065 Estimating Water Stress in Plants Using 2004 Abstract. The ability to estimate plant water content may provide valuable information plant species (corn, spinach and snap beans) grown in a greenhouse and subjected to different watering

Jones, Carol

291

Towards an ontology of waste water treatment plants: the identification phase  

Microsoft Academic Search

Water pollution in Mexico is an important issue in spite of the benefits obtained by current waste water treatment plants; more heuristic knowledge is required to adequately design and operate new plants. This paper discusses the role of the identification phase in the attainment of a knowledge base to obtain a domain ontology of waste water treatment plants. Two examples

Octavio Cabezut-boo; Antonio Sánchez-aguilar

1999-01-01

292

Reconstructing plant root area and water uptake profiles Kiona Ogle1  

E-print Network

. However, current methods for inferring plant water sources based on stable isotopes ("simple linear mixing and least destructive methods for elucidating plant-soil interactions. Plant roots obtain water from various of three (e.g., surface, intermediate, deep soil water); estimation of additional sources leads

West, Mike

293

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

Microsoft Academic Search

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

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

2006-01-01

294

Macroinvertebrates Associated With Emergent Macrophyte Decomposition in a Constructed Wetland.  

NASA Astrophysics Data System (ADS)

This study took place at the San Jacinto constructed wetland in California. Wetland water is supplied to irrigators in this cooperative venture between Reclamation and the Eastern Municipal Water District. One of the problems at this highly productive site is that plant litter accumulates to where it needs to be managed by taking the wetland off-line, thus impacting O&M costs and water delivery schedules for extended periods. Information on decomposition rates and conditions needed to encourage invertebrate decomposers was required to improve wetland reliability and decrease biomass management costs. Standing dead culms of bulrush (Schoenoplectus) were collected and air-dried to constant weight. Twenty-gram culm packs were placed in the wetland and then collected at two month intervals. Comparisons between fine-mesh and coarse-mesh packs demonstrated that exclusion of aquatic invertebrates decreased processing. This was also demonstrated in laboratory studies. It also appeared that culm pack decomposition rate varied with the macroinvertebrate community, and that community distribution was influenced by water quality. Study results confirm the importance of vegetation management through water management and wetland design. Maintaining healthy, sustainable ecosystems will help to encourage natural decomposition processes and maintain better water quality.

Nelson, M.; Thullen, J.; Sartoris, J.

2005-05-01

295

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

ERIC Educational Resources Information Center

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…

South Dakota Dept. of Environmental Protection, Pierre.

296

Hydroxyl radical formation during methane oxidation and water decomposition on Pt measured by laser-induced fluorescence  

SciTech Connect

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.

Mooney, C.E.; Anderson, L.C.; Lunsford, J.H. (Texas A and M Univ., College Station (United States))

1991-08-08

297

Biochemical and molecular responses to water stress in resurrection plants.  

PubMed

A small group of angiosperms, known as resurrection plants, can tolerate extreme dehydration. They survive in arid environments because they are able to dehydrate, remain quiescent during long periods of drought, and then resurrect upon rehydration. Dehydration induces the expression of a large number of transcripts in resurrection plants. Gene products with a putative protective function such as LEA proteins have been identified; they are expressed at high levels in the cytoplasm or in chloroplasts upon dehydration and/or ABA treatment of vegetative tissue. An increase in sugar concentration is usually observed at the onset of desiccation in vegetative tissue of resurrection plants. These sugars may be effective in osmotic adjustment or they may stabilize membrane structures and proteins. Regulatory genes such as a protein translation initiation factor, homeodomain-leucine zipper genes and a gene probably working as a regulatory RNA have been isolated and characterized. The knowledge of the biochemical and molecular responses that occur during the onset of drought may help to improve water stress tolerance in plants of agronomic importance. PMID:15153183

Bernacchia, Giovanni; Furini, Antonella

2004-06-01

298

Fast Approximate Convex Decomposition  

E-print Network

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...

Ghosh, Mukulika

2012-10-19

299

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

PubMed

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

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

2014-06-17

300

Removal of fluoride from water by five submerged plants.  

PubMed

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

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

2012-08-01

301

Photosynthesis, plant growth and dry matter distribution in kiwifruit as influenced by water deficits  

Microsoft Academic Search

The effects of water deficits on photosynthesis, plant growth and dry matter accumulation and distribution in the kiwifruit, cv Hayward, grown under controlled conditions in the glasshouse were studied. Water stress was imposed by irrigating the plants with 100%, 85%, 65% and 40% of water needed to reach pot capacity in the soil. Water deficits reduced the rate of photosynthesis

K. Chartzoulakis; B. Noitsakis; I. Therios

1993-01-01

302

Analysis of an RO plant to remedy the water shortage in the rural area of damascus  

Microsoft Academic Search

Water situation of the rural area of Damascus has been investigated in details including water resources, consumption, shortage and quality. Due to the shortage of potable water, a suitable RO plant was suggested. Full details of its design including its needed pretreatment are presented. Water production cost methodology has been surveyed and applied for the suggested plant.

S. Suleiman; F. Kroma; J. Momjian

2005-01-01

303

Isoprenoids content and photosynthetic limitations in rosemary and spearmint plants under water stress  

Microsoft Academic Search

Water scarcity is one of the most detrimental effects on crop yield. We studied the effect of water stress on carbon acquisition and allocation to monoterpenes of commercial importance in spearmint and rosemary plants. Increasing levels of water stress reduced photosynthesis and plant biomass. Under increasing water-stress levels photosynthesis was limited by low CO2 availability due to reduced stomatal and

S. Delfine; F. Loreto; P. Pinelli; R. Tognetti; A. Alvino

2005-01-01

304

18 CFR 420.51 - Hydroelectric power plant water use charges.  

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...

2014-04-01

305

18 CFR 420.51 - Hydroelectric power plant water use charges.  

Code of Federal Regulations, 2013 CFR

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

2013-04-01

306

18 CFR 420.51 - Hydroelectric power plant water use charges.  

Code of Federal Regulations, 2011 CFR

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...

2011-04-01

307

18 CFR 420.51 - Hydroelectric power plant water use charges.  

Code of Federal Regulations, 2012 CFR

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...

2012-04-01

308

Effects of planting densities on water quality improvements and Pontederia cordata's physiology.  

PubMed

Various planting densities (5, 10, or 20 plants per tank) of Pontederia cordata were water-cultivated in purifying tanks to treat polluted water. Seasonal effects of the planting densities on the water quality improvement and the morphology and physiology of the plant were analyzed. Results indicated that planting densities affected the nitrogen and phosphorus removal of water, and the morphology and physiology of plants, including activity of peroxidise and catalase, content of chlorophyll and soluble protein (SP), the length of root, stem and leaf, tiller number and root density. When planting density increased from 10 to 20 plants per tank, the morphology and physiology of plants, and the nitrogen and phosphorus removal by plants improved slowly, but caused a tiller number decline in individual plants. This variation was significant in autumn, and associated with seasonal variations of plant physiology. During autumn, there were 26 tillers in each plant with 10 plants per tank, compared to 14 tillers per plant with 20 plants per tank. Increase in the nitrogen and phosphorus contents of the plants for 5-10 plants per tank was 5.41 and 0.79 g kg(-1), compared to 1.17 and 0.12 g kg(-1) for 10-20 plants per tank, respectively. PMID:24912229

Lu, Xiao-Ming; Lu, Peng-Zhen; Chen, Jian-Jun

2014-01-01

309

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

Microsoft Academic Search

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

Anita Roth-Nebelsick

310

Stable Carbon Isotopes As Indicators of Plant Water Use Efficiency  

NASA Astrophysics Data System (ADS)

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.

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

2007-12-01

311

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

SciTech Connect

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

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

1999-10-01

312

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

PubMed

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

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

2014-02-01

313

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

SciTech Connect

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

Sokolov, A. S. [JSC 'B. E. Vedeneev All-Russia Research Institute of Hydraulic Engineering (VNIIG)' (Russian Federation)] [JSC 'B. E. Vedeneev All-Russia Research Institute of Hydraulic Engineering (VNIIG)' (Russian Federation)

2013-07-15

314

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

NASA Astrophysics Data System (ADS)

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

Tardieu, F.

2012-04-01

315

Developments in high recovery brackish water desalination plants as part of the solution to water quantity problems  

Microsoft Academic Search

This paper reviews three ways in which existing brackish water reverse osmosis (BWRO) desalination plants can be modified to increase overall water recovery from the 70–75% range to the 90–95% range. The three techniques used to increase plant recovery are: (i) seawater reverse osmosis (SWRO) for water recovery on the BWRO brine stream; (ii) ZeeWeed® ultrafiltration immersed membranes for water

Asam Almulla; Mohamed Eid; Pierre Côté; John Coburn

2003-01-01

316

Phenol Decomposition Process by Pulsed-discharge Plasma above a Water Surface in Oxygen and Argon Atmosphere  

NASA Astrophysics Data System (ADS)

By-products from phenol by the exposure of pulsed-discharge plasma above a phenol aqueous solution are investigated by gas chromatography mass spectrometry, and the decomposition process of phenol is deduced. When Ar is used as a background gas, catechol, hydroquinone and 4-hydroxy-2-cyclohexene-1-on are produced, and no O3 is detected; therefore, active species such as OH, O, HO2, H2O2, which are produced from H2O in the discharge, can convert phenol into those by-products. When O2 is used as a background gas, formic acid, maleic acid, succinic acid and 4,6-dihydroxy-2,4-hexadienoic acid are produced in addition to catechol and hydroquinone. O3 is produced in the discharge plasma, so that phenol is probably decomposed into 4,6-dihydroxy-2,4-hexadienoic acid by 1,3-dipolar addition reaction with O3, and then 4,6-dihydroxy-2,4-hexadienoic acid can be decomposed into formic acid, maleic acid and succinic acid by 1,3-dipolar addition reaction with O3.

Shiota, Haruki; Itabashi, Hideyuki; Satoh, Kohki; Itoh, Hidenori

317

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...

318

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...

319

Quantitative assessment of water consumption for manufacturing packaged drinking water at Rail Neer Plant -A case study  

Microsoft Academic Search

Case study is based on total production and cumulative water consumption of various water treatment units used in water treatment at Rail Neer Plant, Nangloi, Delhi to meet Bureau of Indian Standards specification for packaged drinking water (IS:14543: 2004) and various amendments incorporated till February 2006. The treatment system comprises of chlorination, activated carbon filtration, pesticide removing system, softener, ultrafiltration,

Brajesh K Shrivastava; Masood Alam

320

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

USGS Publications Warehouse

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

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

2001-01-01

321

Efficient taste and odour removal by water treatment plants around the Han River water supply system.  

PubMed

Seven major water treatment plants in Seoul Metropolitan Area, which are under Korea Water Resources Corporation (KOWACO)'s management, take water from the Paldang Reservoir in the Han River System for drinking water supply. There are taste and odour (T&O) problems in the finished water because the conventional treatment processes do not efficiently remove the T&O compounds. This study evaluated T&O removal by ozonation, granular activated carbon (GAC) treatment, powder activated carbon (PAC) and an advanced oxidation process in a pilot-scale treatment plant and bench-scale laboratory experiments. During T&O episodes, PAC alone was not adequate, but as a pretreatment together with GAC it could be a useful option. The optimal range of ozone dose was 1 to 2 mg/L at a contact time of 10 min. However, with ozone alone it was difficult to meet the T&O target of 3 TON and 15 ng/L of MIB or geosmin. The GAC adsorption capacity for DOC in the three GAC systems (F/A, GAC and O3 + GAC) at an EBCT of 14 min is mostly exhausted after 9 months. However, substantial TON removal continued for more than 2 years (>90,000 bed volumes). GAC was found to be effective for T&O control and the main removal mechanisms were adsorption capacity and biodegradation. PMID:17489399

Ahn, H; Chae, S; Kim, S; Wang, C; Summers, R S

2007-01-01

322

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

SciTech Connect

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

NONE

1997-05-01

323

Treating secondary sewage for water use at an air-cooled power plant  

Microsoft Academic Search

The 330MW Wyodak Plant near Gillette, Wyo. is the world's largest air-cooled power plant and the largest plant to use secondary sewage treatment effluent as the primary source of water for all uses except domestic supply. These uses include ash sluicing, fire protection, auxiliary cooling, and boiler cycle makeup, with each use requiring different treatments. The water treatments used to

H. Bydalek; J. F. Kroon; A. H. Seekamp

1977-01-01

324

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

E-print Network

Plant-wide Control for Better De-oiling of Produced Water in Offshore Oil & Gas Production Zhenyu of plant-wide control philosophy to enhance the performance and capacity of the Produced Water Treatment: Large-scale complex systems, plant-wide control, bifurcation, Oil & gas production 1. INTRODUCTION

Yang, Zhenyu

325

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

SciTech Connect

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

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

2009-04-03

326

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

PubMed Central

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

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

2012-01-01

327

Mathematical modelling of plant water and nutrient uptake  

NASA Astrophysics Data System (ADS)

In this presentation I will describe a model of plant water and nutrient uptake and how to translate this model and experimental data from the single root scale to the root branching structure scale. The model starts at the single root scale and describes the water and nutrient movement in the soil using Richards' equation (water uptake) and diffusion-convection equation (nutrient uptake). The water and nutrient uptake in the single root scale model is represented by boundary conditions. In the case of nutrient uptake this has the form of a non-linear Michaelis-Menten uptake law and in the case of water this is given by a soil-xylem pressure difference boundary condition. The flow of water in the xylem is modeled as Poiseuille flow. We solve the single root scale models using the analytic approximate technique of asymptotic expansions similar to Oseen expansions known from fluid dynamics. We will then discuss how to use the analytic expression to estimate the water and nutrient uptake by growing root branching systems. We model the growth of the root system using a dynamic population model to describe the branching and elongation of roots in the branching system. This root branching population model results in a hyperbolic equation similar to age dependent population models and it can be solved fully analytically using the method of characteristics. Thus we have a fully analytic description of the root branching system evolution. We use this branching model to estimate the nutrient uptake in a scenario when the competition between subbranches is small, i.e., as it is in the case of phosphate, potassium and arsenic. We compare our approximate analytic model to a full 3d simulation of the root system phosphate uptake and find that the analytic model almost perfectly reproduces the 3d numerical model. In addition the analytic model can be included in larger field/catchment/climate scale models something which is not practically possible with the numerical simulations due to their high computational burden. As a further development of the analytic model we extend it to take into account more details about the root morphology, such as the branching angle between roots, to calculate the evolution of the soil moisture and nutrient concentration profiles due to surface fertilisation and rainfall events. Using this model we are able to determine the relationship between the rainfall events and fertiliser movement into the soil profile. We find that there is a critical rate of rainfall below which the fertilizer (or pollutant) movement into the deeper layers of the soil is impeded due to the development of a slowly varying fluid saturation profile.

Roose, Tiina

2010-05-01

328

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

Microsoft Academic Search

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

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

329

Predawn disequilibrium between plant and soil water potentials in two cold-desert shrubs  

Microsoft Academic Search

Classical water relations theory predicts that predawn plant water potential should be in equilibrium with soil water potential\\u000a (soil ?w) around roots, and many interpretations of plant water status in natural populations are based on this expectation. We examined\\u000a this expectation for two salt-tolerant, cold-desert shrub species in glasshouse experiments where frequent watering assured\\u000a homogeneity in soil ?w and soil-root

L. A. Donovan; D. J. Grisé; J. B. West; R. A. Pappert; N. N. Alder; J. H. Richards

1999-01-01

330

Natural selection on the plant-water relations of Cleome serrulata growing along natural moisture gradients  

Microsoft Academic Search

I investigated the extent and adaptive importance of genetically-based variation in plant water relations in two populations of the annual plant Cleome serrulata found growing along relatively short (Plant in May and June of 1984; differences up to 0.9 MPa were seen along the gradients. Seeds were collected from maternal plants growing along the moisture gradients and then grown under

M. A. Farris

1987-01-01

331

Partitioning mycorrhizal influence on water relations of Phaseolus vulgaris into soil and plant components  

Microsoft Academic Search

There is growing appreciation of arbuscular mycorrhizal effects on soil properties and their potential conse- quences on plant behavior. We examined the possibility that mycorrhizal soil may directly influence plant water rela- tions. Using wild-type and noncolonizing bean mutants planted into soils previously produced using mycorrhizal or nonmycorrhizal sorghum plants, we partitioned mycorrhizal influence on stomatal conductance and drought resistance

Robert M. Augé; David M. Sylvia; Soon Park; Brian R. Buttery; Arnold M. Saxton; Jennifer L. Moore; Keunho Cho

2004-01-01

332

2006 Nature Publishing Group Plants are a rich source of nutrients and water for  

E-print Network

© 2006 Nature Publishing Group Plants are a rich source of nutrients and water for microbes, insects or cultivation practices. They enter plant tissues either by wounds or through natural openings plant tissues or the xylem. Plant-pathogenic members of the Proteobacteria cause diverse disease

Pawlowski, Wojtek

333

Studies on water-steam Rankine-cycle solar central receiver power plants. Final report  

Microsoft Academic Search

Cost estimates are provided for four 150 MWe solar hybrid central receiver power plants, based on the updating of conceptual designs developed in a previous EPRI solar hybrid power plant cost study, Water\\/Steam Rankine Cycle Solar Central Receiver Power Plant Cost Estimates. The power plants are hybrid in that main steam is generated in a central receiver and a conventional

J. R. Darnell; R. L. Lessley; J. A. Paffenbarger; A. A. Agur

1985-01-01

334

Optimization of Energy and Water Consumption in Corn-Based Ethanol Plants  

Microsoft Academic Search

In this paper we study the simultaneous energy and water consumption in corn-based ethanol plants. The goal is to reduce the freshwater consumption and waste water discharge. We consider the corn-based ethanol plant reported in Karuppiah et al. (2008). First, we review the major alternatives in the optimization of energy consumption and its impact in water consumption. Next, for each

Elvis Ahmetovic?; Mariano Marti?n; Ignacio E. Grossmann

2010-01-01

335

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

Microsoft Academic Search

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

J. S. Sperry; U. G. Hacke

2002-01-01

336

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

Microsoft Academic Search

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

S. Knoblauch

2009-01-01

337

Water minimization in process industries: case study in beet sugar plant  

Microsoft Academic Search

In this article, an extended and combined systematic approach for water minimization in process industries is presented. Environmental, organizational and economic aspects of water minimization were taken into consideration. Systematic approach was developed and tested with the water minimization project in a sugar plant. A detailed survey of water and wastewater streams was carried out and several options for water

L. Žbontar Zver; P. Glavi?

2005-01-01

338

Techniques and experimental approaches for the measurement of plant water status  

Microsoft Academic Search

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

Neil C. Turner

1981-01-01

339

Optimal Water Network with Zero Wastewater Discharge in an Alumina Plant  

Microsoft Academic Search

Zero wastewater discharge has been the ultimate goal of green water utilization in process industries. To make the water network with zero wastewater discharge economically beneficial, the system should be optimized. Alumina industry is a heavy water consumption industry, hence studying water re-use and zero wastewater discharge (ZWD) for water system in alumina plants is very important. This paper analyzes

CHUN DENG; XIAO FENG

2009-01-01

340

Spatial decomposition and assignment of infrared spectra of simple ions in water from mid-infrared to THz frequencies: Li(+)(aq) and F(-)(aq).  

PubMed

Ionic hydration is of fundamental relevance from chemical reactivity in aqueous solution to biomolecular function at physiological conditions. Vibrational spectroscopy belongs to the most widely used experimental methods in studies of solvation phenomena. There is, however, still limited molecular understanding as to how the vibrational response of solutions is modulated by the presence of solvation shells around solutes, i.e., by interfacial water. Liquid-state THz spectroscopy has been demonstrated to be able to detect even small solute-induced changes of the hydrogen bond dynamics at the solute-water interface. In many cases it reveals rather long-ranged dynamical correlations around solutes, involving many solvent molecules, that can be tackled theoretically by analyzing vibrational spectra in a distance-resolved manner. Here, several spatial decomposition schemes for infrared spectra are used to reveal the distinct distance- and frequency-dependent contributions of the solvation shells to the spectral response in aqueous solutions of Li(+) and F(-). The importance of an explicit representation of the solute's electronic structure for the proper description of solute-solvent polarization effects is demonstrated. The solvent's response to the presence of the solute is systematically disentangled and reveals important differences between the spectral responses due to intra- and intermolecular motion as probed in the mid- and far-infrared spectral windows, respectively. PMID:23822313

Smiechowski, Maciej; Forbert, Harald; Marx, Dominik

2013-07-01

341

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

PubMed Central

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

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

2014-01-01

342

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

PubMed

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

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

2014-01-01

343

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

Federal Register 2010, 2011, 2012, 2013

...Knowledge and Abilities Catalog for Nuclear Power Plant Operators: Advanced Boiling Water Reactors AGENCY: Nuclear Regulatory Commission. ACTION...Knowledge and Abilities Catalog for Nuclear Power Plant Operators: Advanced...

2012-01-20

344

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

USGS Publications Warehouse

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.

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

1997-01-01

345

An integrated performance assessment framework for water treatment plants.  

PubMed

An innovative framework for the performance assessment of a traditional water treatment plant (WTP) is presented that integrates the concepts of reliability, robustness, and Quantitative Microbial Risk Assessment (QMRA). Performance assessment for a WTP comprised of three units (i.e., unit 1: Coagulation/Flocculation and Sedimentation; unit 2: Filtration, and unit 3: Disinfection) was conducted. Performance functions for units 1, 2, and units 1 and 2 combined, were constructed by integrating turbidity robustness indices. Performance function for chlorine disinfection was developed based on the difference between achieved and required CT values. A health-based performance function was developed by comparing the target daily infection rate to the site-specific infection rate. It was used to identify whether the health-based target was met during the failures of units 1 to 3. Results obtained from the proposed performance functions can be used by operators to ensure that multiple barriers perform successfully under variable conditions. PMID:22244994

Zhang, Kejiang; Achari, Gopal; Sadiq, Rehan; Langford, Cooper H; Dore, Mohammed H I

2012-04-15

346

Water quality investigation of Kingston Fossil Plant dry ash stacking  

SciTech Connect

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

Bohac, C.E.

1990-04-01

347

Basic Study on Estimating Water Stress of a Plant Using Vibration Measurement of Leaf  

NASA Astrophysics Data System (ADS)

A new noninvasive method for estimating the water stress of a plant was proposed. In order to investigate this method, we first examined the characteristic frequency of an individual leaf picked from the plant, and obtained the result that its characteristic frequency decreased in proportion to the reduction in the water content of the leaf. Next, we applied this method to a leaf on a branch and confirmed the same tendency when the water stress was increased by stopping the water supply of a plant cultured in water. From these results, it was suggested that the water stress of the plant could be estimated from the vibration measurement of the leaf. Lastly, the relationship between the water potential of the leaf and its elastic constant was discussed with the soil-plant-atmosphere-continuum model (SPAC model), and Young's modulus of a tomato leaf was roughly estimated.

Sano, Motoaki; Sugimoto, Tsuneyoshi; Hosoya, Hiroshi; Ohaba, Motoyoshi; Shibusawa, Sakae

2013-07-01

348

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

NASA Astrophysics Data System (ADS)

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.

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

2005-12-01

349

Effects of climate change on water demand and water availability for power plants - examples for the German capital Berlin  

NASA Astrophysics Data System (ADS)

Effects of climate change on water demand and water availability for power plants - examples for the German capital Berlin Stefan Vögelea, Hagen Kochb&c, Uwe Grünewaldb a Forschungszentrum Jülich, Institute of Energy Research - Systems Analysis and Technology Evaluation, D-52425 Jülich, Germany b Brandenburg University of Technology Cottbus, Chair Hydrology and Water Resources Management, P.O. Box. 101 344, D-03013 Cottbus, Germany c Potsdam Institute for Climate Impact Research, Research Domain Climate Impacts and Vulnerabilities, P.O. Box 601203, D-14412 Potsdam, Germany Numerous power plants in Europe had to be throttled in the summer months of the years 2003 and 2006 due to water shortages and high water temperatures. Therefore, the effects of climate change on water availability and water temperature, and their effects on electric power generation in power plants have received much attention in the last years. The water demand of a power plant for cooling depends on the temperature of the surface waters from which the cooling water is withdrawn. Furthermore, air temperature and air humidity influence the water demand if a cooling tower is used. Beside climatic parameters, the demand for water depends on economic and technological factors as well as on the electricity demand and the socio-political framework. Since the different systems are connected with certain levels of uncertainty, scenarios of socio-economic development and climate change should be used in analyses of climate change on power plants and to identify adaptation measures. In this presentation the effects of global change, comprising technological, socio-economic and climate change, and adaptation options to water shortages for power plants in the German capital Berlin in the short- and long-term are analysed. The interconnection between power plants, i.e. water demand, and water resources management, i.e. water availability, is described in detail. By changing the cooling system of power plants from once-through system to closed circuit cooling systems and/or increasing their efficiency the vulnerability of power plants can be reduced considerably. So the electricity production becomes much more robust against effects of climate change and declining streamflows due to human activities in the basin under study. Notwithstanding of the adaptation options analysed for power plants in Berlin economic costs are expected due to declining streamflows and higher water temperatures.

Voegele, Stefan; Koch, Hagen; Grünewald, Uwe

2010-05-01

350

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

SciTech Connect

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

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

1998-01-29

351

Dioecy Impacts on Plant Water Fluxes in Riparian Ecosystems  

NASA Astrophysics Data System (ADS)

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.

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

2005-12-01

352

Changes in Resistance to Flow of Water through a Soil-Plant System.  

National Technical Information Service (NTIS)

A method employing the use of both a hanging water column and a field type thermocouple psychrometer was developed to control and measure water potential gradients in pepper plants with confined root systems. Small soil containers were constructed with Mi...

B. E. Janes, G. W. Gee

1970-01-01

353

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

SciTech Connect

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

Not Available

2002-12-01

354

Management regimes affect woody plant productivity and water use efficiency in an urban desert ecosystem  

Microsoft Academic Search

Woody plant productivity and water use were evaluated under various management regimes in the Central Arizona Phoenix Long\\u000a Term Ecological Research study area during 1999–2003. Management was defined as alteration of plant density, irrigation of\\u000a plants, and removal of plant biomass via pruning. In a ground survey of 204 randomly chosen sites woody plant canopy area\\u000a (CA) was higher in

L. Brooke Stabler

2008-01-01

355

Comparison of Austenite Decomposition Models During Finite Element Simulation of Water Quenching and Air Cooling of AISI 4140 Steel  

NASA Astrophysics Data System (ADS)

An indigenous, non-linear, and coupled finite element (FE) program has been developed to predict the temperature field and phase evolution during heat treatment of steels. The diffusional transformations during continuous cooling of steels were modeled using Johnson-Mehl-Avrami-Komogorov equation, and the non-diffusion transformation was modeled using Koistinen-Marburger equation. Cylindrical quench probes made of AISI 4140 steel of 20-mm diameter and 50-mm long were heated to 1123 K (850 °C), quenched in water, and cooled in air. The temperature history during continuous cooling was recorded at the selected interior locations of the quench probes. The probes were then sectioned at the mid plane and resultant microstructures were observed. The process of water quenching and air cooling of AISI 4140 steel probes was simulated with the heat flux boundary condition in the FE program. The heat flux for air cooling process was calculated through the inverse heat conduction method using the cooling curve measured during air cooling of a stainless steel 304L probe as an input. The heat flux for the water quenching process was calculated from a surface heat flux model proposed for quenching simulations. The isothermal transformation start and finish times of different phases were taken from the published TTT data and were also calculated using Kirkaldy model and Li model and used in the FE program. The simulated cooling curves and phases using the published TTT data had a good agreement with the experimentally measured values. The computation results revealed that the use of published TTT data was more reliable in predicting the phase transformation during heat treatment of low alloy steels than the use of the Kirkaldy or Li model.

Babu, K.; Prasanna Kumar, T. S.

2014-08-01

356

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

NASA Astrophysics Data System (ADS)

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).

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

2008-12-01

357

Plants water status of the shelterbelt along the Tarim Desert Highway  

Microsoft Academic Search

The plant water consumption and irrigation management are the core issue of the sustainable growing of the Tarim Desert Highway\\u000a shelterbelt in the hyperaride Taklimakan Desert. The stem sap flow, water status and water consumption of shelterbelt plants\\u000a were studied, then, the issue of the water save in the process of shelterbelt irrigation management was discussed by measuring\\u000a the sap

Hao Xu; XiMing Zhang; HaiLong Yan; ShaoMin Liang; LiShan Shan

2008-01-01

358

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

PubMed

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

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

2006-04-01

359

Hydraulics of Asteroxylon mackei, an early Devonian vascular plant, and the early evolution of water transport tissue in terrestrial plants.  

PubMed

The core of plant physiology is a set of functional solutions to a tradeoff between CO(2) acquisition and water loss. To provide an important evolutionary perspective on how the earliest land plants met this tradeoff, we constructed a mathematical model (constrained geometrically with measurements of fossils) of the hydraulic resistance of Asteroxylon, an Early Devonian plant. The model results illuminate the water transport physiology of one of the earliest vascular plants. Results show that Asteroxylon's vascular system contains cells with low hydraulic resistances; these resistances are low because cells were covered by scalariform pits, elliptical structures that permit individual cells to have large areas for water to pass from one cell to another. Asteroxylon could move a large amount of water quickly given its large pit areas; however, this would have left these plants particularly vulnerable to damage from excessive evapotranspiration. These results highlight a repeated pattern in plant evolution, wherein the evolution of highly conductive vascular tissue precedes the appearance of adaptations to increase water transport safety. Quantitative insight into the vascular transport of Asteroxylon also allows us to reflect on the quality of CO(2) proxy estimates based on early land plant fossils. Because Asteroxylon's vascular tissue lacked any safety features to prevent permanent damage, it probably used stomatal abundance and behavior to prevent desiccation. If correct, low stomatal frequencies in Asteroxylon reflect the need to limit evapotranspiration, rather than adaptation to high CO(2) concentrations in the atmosphere. More broadly, methods to reveal and understand water transport in extinct plants have a clear use in testing and bolstering fossil plant-based paleoclimate proxies. PMID:21244621

Wilson, J P; Fischer, W W

2011-03-01

360

Water use at pulverized coal power plants with postcombustion carbon capture and storage.  

PubMed

Coal-fired power plants account for nearly 50% of U.S. electricity supply and about a third of U.S. emissions of CO(2), the major greenhouse gas (GHG) associated with global climate change. Thermal power plants also account for 39% of all freshwater withdrawals in the U.S. To reduce GHG emissions from coal-fired plants, postcombustion carbon capture and storage (CCS) systems are receiving considerable attention. Current commercial amine-based capture systems require water for cooling and other operations that add to power plant water requirements. This paper characterizes and quantifies water use at coal-burning power plants with and without CCS and investigates key parameters that influence water consumption. Analytical models are presented to quantify water use for major unit operations. Case study results show that, for power plants with conventional wet cooling towers, approximately 80% of total plant water withdrawals and 86% of plant water consumption is for cooling. The addition of an amine-based CCS system would approximately double the consumptive water use of the plant. Replacing wet towers with air-cooled condensers for dry cooling would reduce plant water use by about 80% (without CCS) to about 40% (with CCS). However, the cooling system capital cost would approximately triple, although costs are highly dependent on site-specific characteristics. The potential for water use reductions with CCS is explored via sensitivity analyses of plant efficiency and other key design parameters that affect water resource management for the electric power industry. PMID:21329343

Zhai, Haibo; Rubin, Edward S; Versteeg, Peter L

2011-03-15

361

100 kW CC-OTEC Plant and Deep Ocean water Applications  

E-print Network

. / 1st Power Generation Test Succeeded Surface Water: 23.5 oC, 330t/h Deep Water: 9.3 oC, 250t/h Power100 kW CC-OTEC Plant and Deep Ocean water Applications in Kumejima, Okinawa, Japan Katsuya Furugen in Kumejima (Okinawa) Okinawa Prefectural Deep Sea Water Research Center, since 2000 OTEC Demonstration

362

A process integration approach to industrial water conservation: A case study for a Chinese steel plant  

Microsoft Academic Search

A systematic approach to optimizing water network has traditionally been utilized to exam and plan water conservation in industrial processes. In the present case study, water-pinch technology was used to analyze and optimize the water network of a steel plant near China's Zhangjiakou city. A system design was developed and a limiting constraint (Cl? concentration) was identified based on investigations

J. R. Tian; P. J. Zhou; B. Lv

2008-01-01

363

Percolated water can leach undesirable chemical compounds below the rooting zone of plants and  

E-print Network

) An introduction to global fresh water issues. In: Gleick PH (ed.) Water in Crisis: A Guide to the World's Fresh some societies to subsist in semiarid and arid areas where other sources of fresh water (e.g., riversPercolated water can leach undesirable chemical compounds below the rooting zone of plants

364

Design and Economical Performance of Gray Water Treatment Plant in Rural Region  

Microsoft Academic Search

In India, the quarrel between the budding human populace and the planet's unchanging supply of freshwater and falling water tables has strained attention the reuse of gray water as an alternative water resource in rural development. This paper present the finest design of laboratory scale gray water treatment plant, which is a combination of natural and physical operations such as

Bhausaheb L. Pangarkar; Saroj B. Parjane; M. G. Sane

2010-01-01

365

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. REEVES, Passed Aahfant Engineer U: S.Navy. .Freshwater supply.-The water for the fresh-water aquaria was supplied from one of the water mains under the aquarium building at an average pressure of about 60 pounds

366

Water relations of four perennial plant species at the southern periphery of the Taklimakan desert  

Microsoft Academic Search

The investigations started from the assumption that perennial plants in the foreland of river oases in the Taklimakan desert are able to take up water from soils of low water content and low water potential during long drought periods. In order to check this assumption, P-V curves were established and selected water relation parameters were derived. Alhagi sparsifolia, Calligonum caput-medusae,

XiangYi Li; LiSha Lin; FanJiang Zeng; XiMing Zhang

2011-01-01

367

Importance of permafrost as a source of water for plants in east Siberian taiga  

Microsoft Academic Search

Stable oxygen isotope ratios of plant water (sap water) were observed at Spasskaya Pad experimental forest near Yakutsk, Russia in 1997–1999. The ? 18O of sap water in larch trees ( Larix gmelinii) decreased soon after leaf unfolding every year, indicating that snowmelt water was used in the beginning of summer. During mid to late summer, a clear difference in

Atsuko Sugimoto; Nao Yanagisawa; Daisuke Naito; Noboru Fujita; Trofim C. Maximov

2002-01-01

368

Improvement of chemical control in the water-steam cycle of thermal power plants  

Microsoft Academic Search

A more effective chemical control in the water-steam cycle (WSC) of thermal power plants (TPP) is proposed in this paper. Minimization of corrosion effects by the production of ultra pure water and its strict control is the basis of all the investigated processes. The research involved the analysis of water samples in the WSC through key water quality parameters and

Vladana N. Rajakovi?-Ognjanovi?; Dragana Z. Živojinovic; Branimir N. Grgur; Ljubinka V. Rajakovi?

2011-01-01

369

Effect of residual distillation water of 15 plants and three plant hormones on Scotch spearmint ( Mentha × gracilis Sole)  

Microsoft Academic Search

Distillation waste water is a byproduct from steam distillation of aromatic crops, and is currently discharged into streams and rivers. We evaluated distillation waste water (extract) from 15 essential oil crops plus three plant hormones (methyl jasmonate, MJ; gibberellic acid, GA3; and salicylic acid, SA) as foliar spray for Scotch spearmint (Mentha×gracilis Sole). GA3 and Achillea millefolium extract decreased essential

Valtcho D. Zheljazkov; Tess Astatkie

2011-01-01

370

Hydrogen iodide decomposition  

DOEpatents

Liquid hydrogen iodide is decomposed to form hydrogen and iodine in the presence of water using a soluble catalyst. Decomposition is carried out at a temperature between about 350.degree. K. and about 525.degree. K. and at a corresponding pressure between about 25 and about 300 atmospheres in the presence of an aqueous solution which acts as a carrier for the homogeneous catalyst. Various halides of the platinum group metals, particularly Pd, Rh and Pt, are used, particularly the chlorides and iodides which exhibit good solubility. After separation of the H.sub.2, the stream from the decomposer is countercurrently extracted with nearly dry HI to remove I.sub.2. The wet phase contains most of the catalyst and is recycled directly to the decomposition step. The catalyst in the remaining almost dry HI-I.sub.2 phase is then extracted into a wet phase which is also recycled. The catalyst-free HI-I.sub.2 phase is finally distilled to separate the HI and I.sub.2. The HI is recycled to the reactor; the I.sub.2 is returned to a reactor operating in accordance with the Bunsen equation to create more HI.

O'Keefe, Dennis R. (San Diego, CA); Norman, John H. (San Diego, CA)

1983-01-01

371

Hydrogen iodide decomposition  

SciTech Connect

Liquid hydrogen iodide is decomposed to form hydrogen and iodine in the presence of water using a soluble catalyst. Decomposition is carried out at a temperature between about 350/sup 0/ K. and about 525/sup 0/ K. and at a corresponding pressure between about 25 and about 300 atmospheres in the presence of an aqueous solution which acts as a carrier for the homogeneous catalyst. Various halides of the platinum group metals, particularly Pd, Rh and Pt, are used, particularly the chlorides and iodides which exhibit good solubility. After separation of the H/sub 2/, the stream from the decomposer is countercurrently extracted with nearly dry HI to remove I/sub 2/. The wet phase contains most of the catalyst and is recycled directly to the decomposition step. The catalyst in the remaining almost dry HI-I/sub 2/ phase is then extracted into a wet phase which is also recycled. The catalyst-free HI-I/sub 2/ phase is finally distilled to separate the HI and I/sub 2/. The HI is recycled to the reactor; the I/sub 2/ is returned to a reactor operating in accordance with the Bunsen equation to create more HI.

O'Keefe, D.R.; Norman, J.H.

1983-10-18

372

Management intensity alters decomposition via biological pathways  

USGS Publications Warehouse

Current conceptual models predict that changes in plant litter chemistry during decomposition are primarily regulated by both initial litter chemistry and the stage-or extent-of mass loss. Far less is known about how variations in decomposer community structure (e.g., resulting from different ecosystem management types) could influence litter chemistry during decomposition. Given the recent agricultural intensification occurring globally and the importance of litter chemistry in regulating soil organic matter storage, our objectives were to determine the potential effects of agricultural management on plant litter chemistry and decomposition rates, and to investigate possible links between ecosystem management, litter chemistry and decomposition, and decomposer community composition and activity. We measured decomposition rates, changes in litter chemistry, extracellular enzyme activity, microarthropod communities, and bacterial versus fungal relative abundance in replicated conventional-till, no-till, and old field agricultural sites for both corn and grass litter. After one growing season, litter decomposition under conventional-till was 20% greater than in old field communities. However, decomposition rates in no-till were not significantly different from those in old field or conventional-till sites. After decomposition, grass residue in both conventional- and no-till systems was enriched in total polysaccharides relative to initial litter, while grass litter decomposed in old fields was enriched in nitrogen-bearing compounds and lipids. These differences corresponded with differences in decomposer communities, which also exhibited strong responses to both litter and management type. Overall, our results indicate that agricultural intensification can increase litter decomposition rates, alter decomposer communities, and influence litter chemistry in ways that could have important and long-term effects on soil organic matter dynamics. We suggest that future efforts to more accurately predict soil carbon dynamics under different management regimes may need to explicitly consider how changes in litter chemistry during decomposition are influenced by the specific metabolic capabilities of the extant decomposer communities.

Wickings, Kyle; Grandy, A. Stuart; Reed, Sasha; Cleveland, Cory

2011-01-01

373

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

PubMed

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

Stillwell, Ashlynn S; Webber, Michael E

2014-04-15

374

The Impact of Soil Water Repellency on Hydrological Properties of Soil, the Plant Growing Environment, Irrigation Efficiency and Water Consumption  

NASA Astrophysics Data System (ADS)

Soil water repellency causes at least temporal changes in the hydrological properties of a soil. These changes, among other things, often result in suboptimal growing conditions, reduced crop performance, and/or increased irrigation requirements. Water repellency in soil is more wide spread than previously thought and has been identified in many soil types under a wide array of climatic conditions and cropping systems worldwide. (Dekker et al., 2005) The reduction or loss of soil wettability caused by soil water repellency leads to drastically different hydrological behavior (Dekker et al. 2009), and reduces the ability of the soil to function as expected. Consequences of soil water repellency include increased runoff and preferential flow, reduced plant available water, reduced irrigation efficiency, suboptimal crop performance, increased requirement for water and other inputs, and increased potential for non-point source pollution. (Dekker et al., 2001) This presentation consolidates information on basic hydrological and soil system functions as they relate to the plant growth environment, irrigation efficiency and water conservation, and shows the differences between what happens in soils affected by varying levels of soil water repellency compared to wettable soils or soils where soil surfactants have been used to restore/optimize wettability. The impact on irrigation efficiency and the plant growth environment is also discussed. The conclusion is that the impact of soil water repellency compromises hydrological properties and the plant growth environment in a wider range of conditions than previously recognized and, therefore, deserves consideration in the management of soil and water in crop systems.

Moore, Demie; Kostka, Stanley; Boerth, Thomas; McMillan, Mica; Ritsema, Coen; Dekker, Louis; Oostindie, Klaas; Stoof, Cathelijne; Wesseling, Jan

2010-05-01

375

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

PubMed Central

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

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

2014-01-01

376

Model-Free Based Water Level Control for Hydroelectric Power Plants  

E-print Network

Model-Free Based Water Level Control for Hydroelectric Power Plants Cédric JOIN Gérard ROBERT polytechnique, 91128 Palaiseau, France (e-mail: Michel.Fliess@polytechnique.edu) Abstract: Automatic water level for hydroelectric run-of-the river power plants. To modulate power generation, a level trajectory is planned

Paris-Sud XI, Université de

377

Sustainable Use of Resources Recycling of Sewage Treatment Plant Water in Concrete  

E-print Network

Sustainable Use of Resources ­ Recycling of Sewage Treatment Plant Water in Concrete Marcia Silva1, especially partially processed sewage treatment plant water in concrete. On the basis of identified knowledge. The concrete industry is a significant contributor to air pollution and also a consumer of vast quantities

Wisconsin-Milwaukee, University of

378

Vascular plants for water pollution control and renewable sources of energy  

Microsoft Academic Search

Vascular aquatic plants have demonstrated their ability to remove pollutants from domestic and chemical wastewaters. Plants such as the water hyacinth (Eichhornia crassipes), duckweed (Lemna sp., Spirodela sp., and Wolffia sp.), and cattail (Typha sp.) thrive in nutrient-rich waters and produce tremendous quantities of biomass under favorable climatic conditions. This method of wastewater treatment is currently being used exclusively at

B. C. Wolverton; R. C. McDonald

1980-01-01

379

Intensive or extensive use of soil moisture: Plant strategies to cope with stochastic water availability  

NASA Astrophysics Data System (ADS)

Some plants rely on a dependable winter recharge, as opposed to others that quickly respond to the intermittent and uncertain rainfall during the growing season. Using a stochastic model for the soil moisture process and a quantitative measure of plant water stress, we find climate, soil, and vegetation characteristics leading to the dominance or possible coexistence of these two strategies of water use.

Rodriguez-Iturbe, Ignacio; Porporato, Amilcare; Laio, Francesco; Ridolfi, Luca

380

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

Microsoft Academic Search

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.

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

1987-01-01

381

Ecological Survey of Coastal I Water Adjacent to Nuclear Power I Plants in Taiwan  

Microsoft Academic Search

A total of six nuclear reactors installed in three power plants, two along the northern and one along the southern coasts of Taiwan, started their operations one after another since October 1977. Owing to the large quantities of cooling water intake into and discharge from the plants, some environmental factors such as water temperature, chlorine, environmental radioactivity and nearshore currents

Tsu-Chang Hung; Che-Chung Huang; Kwang-Tsao Shao

1998-01-01

382

Measuring yield-reducing plant water potential depressions in wheat by infrared thermometry  

Microsoft Academic Search

Measurements of foliage and air wet- and dry-bulb temperatures were made over six differentially irrigated plots of Produra wheat grown at Phoenix, Arizona, in the spring of 1976. These data were used to evaluate a newly developed plant water stress index each day from the initiation of heading to the commencement of senescence. Daily measurements on total plant water potential

S. B. Idso; R. J. Reginato; R. D. Jackson; P. J. Pinter

1981-01-01

383

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

PubMed

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

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

2014-01-01

384

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

NASA Astrophysics Data System (ADS)

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.

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

2014-10-01

385

A novel modelling and decomposition strategy for overall refinery optimisation  

Microsoft Academic Search

In this paper, a novel decomposition strategy is presented to tackle large-scale overall refinery optimisation problems. This decomposition approach is derived from analysis of the mathematical structure of a general overall plant model, which contains common elements and independent elements. This understanding forms the basis for decomposing the overall plant model into two levels, namely a site level (master model),

N. Zhang; X. X. Zhu

2000-01-01

386

Effects of Static versus Flowing Water on Aquatic Plant Preferences of Triploid Grass Carp  

Microsoft Academic Search

Triploid grass carp Ctenopharyngodon idella were presented with three aquatic plant species (sago pondweed Potamogeton pectinatus, Eurasian watermilfoil Myriophyllum spicatum, and American pondweed P. nodosus) in outdoor canals with static and flowing water in winter, spring, and summer. Plant consumption by triploid grass carp in winter was low but increased dramatically in spring and summer. Based on plant shoot lengths,

Robert T. Pine; Lars W. J. Anderson; Silas S. O. Hung

1989-01-01

387

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

Microsoft Academic Search

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

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

1998-01-01

388

MAGNITUDE AND MECHANISMS OF DISEQUILIBRIUM BETWEEN PREDAWN PLANT AND SOIL WATER POTENTIALS  

Microsoft Academic Search

Predawn plant water potential (Cw, measured with leaf psychrometers) and surrogate measurements made with the pressure chamber (termed Cpc here) are used to infer comparative ecological performance, based on the expectation that these plant po- tentials reflect the wettest soil Cw accessed by roots. There is growing evidence, however, that some species exhibit substantial predawn disequilibrium (PDD), defined as plant

Lisa A. Donovan; James H. Richards; Matthew J. Linton

2003-01-01

389

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

EPA Science Inventory

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

390

Water uptake, water use efficiency, plant growth and ionic balance of wheat, barley, canola and chickpea plants on a sodic vertosol with variable subsoil NaCl salinity  

Microsoft Academic Search

Salinity in topsoil and subsoil is one of the major abiotic environmental stresses to crop production. To investigate the comparative tolerance ability of wheat, barley, canola and chickpea to subsoil NaCl salinity and its impact on water uptake, water use efficiency, plant growth and ionic balance, a pot experiment was conducted on a heavy texture soil (sodic vertosol) having 20

Harsharn Singh Grewal

2010-01-01

391

The effects of power plant effluents on the growth of phytoplankton in adjacent estuarine waters  

E-print Network

Bayou that is caused by the power plant's operation may transfer polluted water from the Houston Ship Channel to Trinity Bay. Also, Johnson (1973) stated that a United States Steel Company's plant is dis- charging a heated effluent through natural... productivity difference. The rates of phytoplankton photosynthesis were used by Morgan and Stress (1969) to evaluate the response of phytoplankton which passed through the cooling system of a power plant utilizing Chesapeake Bay water. They found...

Shieh, Dah-Wen

2012-06-07

392

Effect of transpiration rate on internal plant resistance to water flow  

E-print Network

of the literatures an Ohm's law analogy seems applicable in the liquid phase of water transpor t in plants Exper iments to verify this views that the internal plant resistance to water flow in southern peas (Vigna sinensis L ~ Endl. var ~ Burgundy) does... AND DISCUSSION Transpiration Rate and Internal Plant Resistance for Southern Peas Leaf Diffusion Resistances. Leaf Temperatures and Stem Diameter ~ Total Resistance to Vapor Diffusion from Leaf to Air ~ ~ Engineering Application of Results V SUMMARY...

Hailey, James Lester

2012-06-07

393

Effects of Salinity on Growth, Ionic Content, and Plant–Water Status of Aeluropus lagopoides  

Microsoft Academic Search

The effect of sodium chloride (NaCl) in the external medium upon the growth, plant–water status, and ionic content of Aeluropus lagopoides was studied. Plants grown in non-saline and 200 mM NaCl had the greatest fresh and dry weights. Increasing salinity (400 to 1000 mol m NaCl) caused a decrease in fresh and dry weights of plants. The water potential and osmotic potential of

Salman Gulzar; M. Ajmal Khan; Irwin A. Ungar

2003-01-01

394

The use of soil electrical resistivity to monitor plant and soil water relationships in vineyards  

NASA Astrophysics Data System (ADS)

Soil water availability deeply affects plant physiology. In viticulture it is considered as a major contributor to the "terroir" expression. The assessment of soil water in field conditions is a difficult task especially over large surfaces. New techniques, are therefore required to better explore variations of soil water content in space and time with low disturbance and with great precision. Electrical Resistivity Tomography (ERT) meets these requirements, for applications in plant sciences, agriculture and ecology. In this paper, possible techniques to develop models that allow the use of ERT to spatialise soil water available to plants are reviewed. An application of soil water monitoring using ERT in a grapevine plot in Burgundy (north-east of France) during the vintage 2013 is presented. We observed the lateral heterogeneity of ERT derived Fraction of Transpirable Soil Water (FTSW) variations, and differences in water uptake depending on grapevine water status (leaf water potentials measured both at predawn and at solar noon and contemporary to ERT monitoring). Active zones in soils for water movements were identified. The use of ERT in ecophysiological studies, with parallel monitoring of plant water status, is still rare. These methods are promising because they have the potential to reveal a hidden part of a major function of plant development: the capacity to extract water from the soil.

Brillante, L.; Mathieu, O.; Bois, B.; van Leeuwen, C.; Lévêque, J.

2014-10-01

395

Prevention and mitigation of steam-generator water-hammer events in PWR plants  

SciTech Connect

Water hammer in nuclear power plants is an unresolved safety issue under study at the NRC (USI A-1). One of the identified safety concerns is steam generator water hammer (SGWH) in pressurized-water reactor (PWR) plants. This report presents a summary of: (1) the causes of SGWH; (2) various fixes employed to prevent or mitigate SGWH; and (3) the nature and status of modifications that have been made at each operating PWR plant. The NRC staff considers that the issue of SGWH in top feedring designs has been technically resolved. This report does not address technical findings relevant to water hammer in preheat type steam generators. 10 figures, 2 tables.

Han, J.T.; Anderson, N.

1982-11-01

396

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

NASA Astrophysics Data System (ADS)

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.

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

2013-12-01

397

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

PubMed

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

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

2010-12-01

398

Study of the ionome and uptake fluxes in cherry tomato plants under moderate water stress conditions  

Microsoft Academic Search

Nutritional imbalance under water-deficit conditions depresses plant growth by affecting nutrient uptake, transport, and distribution.\\u000a The present work analyses the variations in the foliar concentrations of macro- and micronutrients as well as the transport\\u000a of these nutrients in five cherry tomato cultivars under well-watered and moderately water-stressed conditions with the aim\\u000a of establishing whether the ionome of the plants is

Eva Sánchez-Rodríguez; Maria del Mar Rubio-Wilhelmi; Luis Miguel Cervilla; Begoña Blasco; Juan Jose Rios; Rocio Leyva; Luis Romero; Juan Manuel Ruiz

2010-01-01

399

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

Microsoft Academic Search

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

Hans-Holger Liste; Jason C. White

2008-01-01

400

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

Microsoft Academic Search

\\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

Juan Manuel Ruiz-Lozano; Ricardo Aroca

401

WATER REUSE IN A WET PROCESS HARDBOARD MANUFACTURING PLANT  

EPA Science Inventory

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

402

Basic dye decomposition kinetics in a photocatalytic slurry reactor.  

PubMed

Wastewater effluent from textile plants using various dyes is one of the major water pollutants to the environment. Traditional chemical, physical and biological processes for treating textile dye wastewaters have disadvantages such as high cost, energy waste and generating secondary pollution during the treatment process. The photocatalytic process using TiO2 semiconductor particles under UV light illumination has been shown to be potentially advantageous and applicable in the treatment of wastewater pollutants. In this study, the dye decomposition kinetics by nano-size TiO2 suspension at natural solution pH was experimentally studied by varying the agitation speed (50-200 rpm), TiO2 suspension concentration (0.25-1.71 g/L), initial dye concentration (10-50 ppm), temperature (10-50 degrees C), and UV power intensity (0-96 W). The experimental results show the agitation speed, varying from 50 to 200 rpm, has a slight influence on the dye decomposition rate and the pH history; the dye decomposition rate increases with the TiO2 suspension concentration up to 0.98 g/L, then decrease with increasing TiO2 suspension concentration; the initial dye decomposition rate increases with the initial dye concentration up to a certain value depending upon the temperature, then decreases with increasing initial dye concentration; the dye decomposition rate increases with the UV power intensity up to 64 W to reach a plateau. Kinetic models have been developed to fit the experimental kinetic data well. PMID:16563618

Wu, Chun-Hsing; Chang, Hung-Wei; Chern, Jia-Ming

2006-09-01

403

Depletion of heavy isotopes of oxygen and hydrogen in tissue water of intertidal plants: implications for water economy  

Microsoft Academic Search

Stable oxygen and hydrogen isotope ratios of leaf and thallus water of the intertidal seagrasses Phyllospadix scouleri and P. torreyi and the marine algae Egregia menziesii, Gelidium coulteri, and Corallina vancouverensis from three locations in California, USA, were determined in 1987. Compared with subtidal seawater, most plant-water samples were depleted in the heavy isotopes 18O and deuterium. Depletion of heavy

L. W. Cooper; M. J. DeNiro

1989-01-01

404

Heat recovery from waste water by energy-saving heat pump systems in connection with water treatment plants  

Microsoft Academic Search

The advantages of waste water recovery as an energy source were investigated. It was found that heat pump systems reach the highest performance coefficients and their primary energy ratios are competitive with conventional heating systems. It is concluded that the utilization of waste water treatment plants by large heat pump systems provides a considerable annual energy saving of light oil.

U. Wiedmann; R. Flohrschuetz

1980-01-01

405

Impacts of oil sands process water on fen plants: implications for plant selection in required reclamation projects.  

PubMed

Fen plant growth in peat contaminated with groundwater discharges of oil sands process water (OSPW) was assessed in a greenhouse over two growing seasons. Three treatments (non-diluted OSPW, diluted OSPW and rainwater) were tested on five vascular plants and four mosses. All vascular plants tested can grow in salinity and naphthenic acids levels currently produced by oil sands activity in northwestern Canada. No stress sign was observed after both seasons. Because of plant characteristics, Carex species (C. atherodes and C. utriculata) and Triglochin maritima would be more useful for rapidly restoring vegetation and creating a new peat-accumulating system. Groundwater discharge of OSPW proved detrimental to mosses under dry conditions and ensuring adequate water levels would be crucial in fen creation following oil sands exploitation. Campylium stellatum would be the best choice to grow in contaminated areas and Bryum pseudotriquetrum might be interesting as it has spontaneously regenerated in all treatments. PMID:22575093

Pouliot, Rémy; Rochefort, Line; Graf, Martha D

2012-08-01

406

Water Impacts of CO2 Emission Performance Standards for Fossil Fuel-fired Power Plants.  

PubMed

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

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

2014-10-21

407

COMMUNITY RESPIRATION OF DECOMPOSING PLANTS IN OREGON ESTUARINE MARSHES  

EPA Science Inventory

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

408

Coupled Soil-Plant Water Dynamics During Drought-Rewetting Transitions  

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

409

The lipid bilayer and aquaporins: parallel pathways for water movement into plant cells  

Microsoft Academic Search

The plant plasma membrane is the the major barrier to water flow between cells and their surroundings. Water movement across roots involves pathways comprising many cells and their walls. There are three possible pathways which water can follow, (i) a trans-cellular pathway, which involves serial movement into and out from radial files of cells, (ii) a symplasmic pathway through the

Micaela Carvajal; David T. Cooke; David T. Clarkson

1998-01-01

410

A simulation model of plant water relations and production in the alpine tundra, Colorado  

Microsoft Academic Search

A model to predict the daily courses of leaf resistance, leaf water potential, transpiration, leaf temperature and net photosynthesis based on soil-plant-atmosphere continuum and energy budget concepts is presented. The principle water relations parameters required by the model are the minimum leaf resistance, the response curves of leaf resistance to light, temperature, and leaf water potential, and the relationship between

James R. Ehleringer; Philip C. Miller

1975-01-01

411

Water relations and photosynthesis of a desert CAM plant, Agave deserti  

Microsoft Academic Search

The water relations and photosynthesis of Agave deserti Engelm., a plant exhibiting Crassulacean acid metabolism, were measured in the Colorado desert. Although no natural stomatal opening of A. deserti occurred in the summer of 1975, it could be induced by watering. The resistance for water vapor diffusion from a leaf (R\\/sub wv\\/) became less than 20 sec cm⁻¹ when the

P. S. Nobel

1976-01-01

412

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

Microsoft Academic Search

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

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

2010-01-01

413

Making the most of increased water flow: Expanding the Devil Canyon hydro plant  

Microsoft Academic Search

Amidst the longest California drought on record, work is proceeding to bring additional water to the southern part of the state. With extra water comes an opportunity for increasing hydro - one project is underway to add 160 MW of power to an existing 120-MW plant. The California State Department of Water Resources (DWR) completed the initial phase of its

B. E. DePuy; R. C. Butler

1992-01-01

414

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

EPA Science Inventory

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

415

A New algorithm for radioisotope concentration monitoring in cooling water outlet of nuclear power plant  

Microsoft Academic Search

In the nuclear power plant (NPP), cooling water is continuously sampled through a small pipe at the outlet before flowing back to the ocean for the purpose of radioactivity concentration monitoring in water. We propose a new algorithm to identify the artificial radioisotopes probably produced in the NPP and released into the cooling water which can be added to the

M. Sohelur Rahman; Gyuseong Cho; Sungho Chang; Jeong Hyun Shin; Junho Lee; Yun Goo Kim; Ki Hyun Park

2007-01-01

416

Influence of paclobutrazol on water consumption and plant performance of Arbutus unedo seedlings  

Microsoft Academic Search

The purpose of this study was to examine the effect of paclobutrazol on the water consumption, plant water relations, gas exchange and development of strawberry tree seedlings (Arbutus unedo L.), to evaluate water resource management. Seedlings (8cm in height) were subjected to a single drench of 60 or 100mg of paclobutrazol and pot-grown in a greenhouse for 4 months. Untreated

Alejandra Navarro; M Sánchez-Blanco; Sebastián Bañon

2007-01-01

417

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

SciTech Connect

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

Not Available

1989-01-01

418

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

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

419

Upgrading and capacity extension of old brackish water desalination plants  

Microsoft Academic Search

In some cases upgrading and extension of old BWRO plants is far more economic in comparison with the development of new plants. This is especially true at sites where expenses related to the infrastructure are high and increase the cost of new installations.Another aspect is technological - usually the operation in the old systems requires excessive energy due to the

P. Glueckstern; M. Priel

2009-01-01

420

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

PubMed

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

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

2010-01-01

421

Ozone decomposition in water solutions  

E-print Network

/R term for pH 8 is -8480. 0 K. Stumm (18) showed. that his experimental data for the pH range of '7. 6 to 10. 4 were characterized by a first order reaction. However, he was the only in- vestigator to reach this conclusion. Sennewald (17) showed.../R term for pH 8 is -8480. 0 K. Stumm (18) showed. that his experimental data for the pH range of '7. 6 to 10. 4 were characterized by a first order reaction. However, he was the only in- vestigator to reach this conclusion. Sennewald (17) showed...

Hewes, Cecil Grayson

2012-06-07

422

Variations in water status, gas exchange, and growth in Rosmarinus officinalis plants infected with Glomus deserticola under drought conditions.  

PubMed

The influence of the arbuscular mycorrhizal fungus Glomus deserticola on the water relations, gas exchange parameters, and vegetative growth of Rosmarinus officinalis plants under water stress was studied. Plants were grown with and without the mycorrhizal fungus under glasshouse conditions and subjected to water stress by withholding irrigation water for 14 days. Along the experimental period, a significant effect of the fungus on the plant growth was observed, and under water stress, mycorrhizal plants showed an increase in aerial and root biomass compared to non-mycorrhizal plants. The decrease in the soil water potential generated a decrease in leaf water potential (psi(l)) and stem water potential (psi(x)) of mycorrhizal and non-mycorrhizal plants, with this decrease being lower in mycorrhizal water-stressed plants. Mycorrhization also had positive effects on the root hydraulic conductivity (Lp) of water stressed plants. Furthermore, mycorrhizal-stressed plants showed a more important decrease in osmotic potential at full turgor (psi(os)) than did non-mycorrhizal-stressed plants, indicating the capacity of osmotic adjustment. Mycorrhizal infection also improved photosynthetic activity (Pn) and stomatal conductance (g(s)) in plants under water stress compared to the non-mycorrhizal-stressed plants. A similar behaviour was observed in the photochemical efficiency of PSII (Fv/Fm) with this parameter being lower in non-mycorrhizal plants than in mycorrhizal plants under water stress conditions. In the same way, under water restriction, mycorrhizal plants showed higher values of chlorophyll content than did non-mycorrhizal plants. Thus, the results obtained indicated that the mycorrhizal symbiosis had a beneficial effect on the water status and growth of Rosmarinus officinalis plants under water-stress conditions. PMID:15266714

Sánchez-Blanco, Ma Jesús; Ferrández, Trinitario; Morales, Ma Angeles; Morte, Asunción; Alarcón, Juan José

2004-06-01

423

Geratology and decomposition of Spartina versicolor in a brackish Mediterranean marsh  

NASA Astrophysics Data System (ADS)

Most studies on plant decomposition in salt marshes have been carried out in Spartina-dominated marshes in North America. In contrast, few have focused on marshes in Mediterranean systems. Moreover, research into litter decay in estuarine systems has been conducted with plant material collected before natural senescence and death. Here we followed the growth, senescence, leaf fall, and nutrient dynamics of Spartina versicolor to examine litter decay in a Mediterranean coastal system. We studied the dynamics of fungi, meiofauna and algae associated with detached S. versicolor litter, and the effect of the microenvironment (above and underneath wracks of dead Spartina) on decomposition. The exponential decay coefficient rate ( k, day -1) was higher for leaves attached to standing plants (0.0019) than after leaf abscission (0.0002-0.001). The decomposition rate of detached leaves was highly variable and depended on the position of the litter. The large differences in decomposition rates between the two experimental conditions indicate that the microenvironment affected the associated litter community during the initial phase of decay. Water availability and high temperatures over the sediment surface increased the density of meiofauna and epiphyton and decreased fungal biomass during the first 20 days of the experiment. Fungal biomass was at the lower end of reported values, probably as a result of the drier conditions and high salinity in the Mediterranean marsh. Spartina versicolor detritus acted as a nutrient sink by immobilizing large amounts of N and P for at least one year.

Menéndez, Margarita; Sanmartí, Neus

2007-08-01

424

CASE STUDY - KRANJI HIGH GRADE WATER RECLAMATION PLANT, SINGAPORE  

Microsoft Academic Search

Increased water demand from population and economic growth, environmental needs, change in rainfall, flood contamination of good quality wate r and over abstraction of groundwater are all factors that continue to create water shortage problems. These changes combined with new legislation are encouraging the development of sustainable water resource strategies. Many national policies now include the promotion of wastewater reuse.

M. Thompson; D. Powell

425

Drought effects on plant water uptake and water use as well as soil carbon dynamics in Swiss grassland systems under changing climate  

E-print Network

Seite 4/7 Drought effects on plant water uptake and water use as well as soil carbon dynamics to drought? Do plants in grassland systems shift to different water sources and use water more efficiently under prolonged drought conditions? How does drought affect soil CO2 losses, organic matter

Richner, Heinz

426

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

SciTech Connect

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

Elcock, D. (Environmental Science Division)

2011-05-09

427

Predictive Modeling of Large-Scale Commercial Water Desalination Plants: Data-Based Neural Network and Model-Based Process  

E-print Network

predictive models of large-scale commercial water desalination plants by (1) a data- based approach usingPredictive Modeling of Large-Scale Commercial Water Desalination Plants: Data-Based Neural Network for developing predictive models for large-scale commercial water desalination plants by (1) a data

Liu, Y. A.

428

Water use efficiency and carbon isotope composition of plants in a cold desert environment  

Microsoft Academic Search

The effects of the availabilities of water and nitrogen on water use efficiency (WUE) of plants were investigated in a sagebrush steppe. The four species studied wereArtemisia tridentata (shrub),Ceratoides lanata (suffrutescent shrub),Elymus lanceolatus (rhizomatous grass), andElymus elymoides (tussock grass). Water and nitrogen levels were manipulated in a two-by-two factorial design resulting in four treatments: control (no additions), added water, added

Nancee L. Toft; Jay E. Anderson; Robert S. Nowak

1989-01-01

429

Optimum operation of desalination plant to minimize power consumption and water shortage risks in Okinawa, Japan  

Microsoft Academic Search

Okinawa Island is located in the southern region of Japan and has a population of 1.22 million. Okinawa Prefectural Enterprise Bureau (OPEB) supplies 410,000?m\\/d of water to 24 municipalities. Although OPEB uses multiple water resources including dam reservoirs and groundwater, increased water demand resulted in occasional water shortages until a seawater desalination plant (40,000?m\\/d) started operations in 1997. In this

Takuya Ishida; Satoshi Takizawa; Naoko Watanabe; Michio Murakami; Hiroshi Sakai; Kumiko Oguma

2012-01-01

430

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

USGS Publications Warehouse

Estimates of water use at thermoelectric plants were developed by the U.S. Geological Survey based on linked heat and water budgets, and complement reported thermoelectric water withdrawals and consumption. The heat- and water-budget models produced withdrawal and consumption estimates, including thermodynamically plausible ranges of minimum and maximum withdrawal and consumption, for 1,290 water-using plants in the United States for 2010. Total estimated withdrawal for 2010 was about 129 billion gallons per day (Bgal/d), and total estimated consumption was about 3.5 Bgal/d. In contrast, total withdrawal reported by the U.S. Department of Energy, Energy Information Administration (EIA), was about 24 percent higher than the modeled estimates, and total EIA-reported consumption was about 8 percent lower. Most thermoelectric generation in 2010 was not associated with thermodynamically plausible EIA-reported values of both withdrawal and consumption. 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.

Diehl, Timothy H.; Harris, Melissa A.

2014-01-01

431

Research Article Kinetic Study of Epoxy Resin Decomposition  

E-print Network

ether type epoxy resin from bisphenol A, E-51, was cured by methyl- hexahydrophthalic anhydride (MeResearch Article Kinetic Study of Epoxy Resin Decomposition in Near-Critical Water A diglycidyl to the saturated water vapor pressure. The kinetics study of the epoxy decomposition was also carried out

Guo, John Zhanhu

432

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

NASA Technical Reports Server (NTRS)

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

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

1987-01-01

433

Impact of storm water runoff on efficiency of the effluent treatment plant - a case study  

SciTech Connect

This paper evaluates the impact of storm water runoff on an existing sewage treatment plant situated in an industrial township. Significant dilution effect is observed during the monsoon period (June-September) in the influent and effluent characteristics of sewage. The estimated excess runoff water during these months is mainly due to the rainfall in the region and due to the absence of proper control or design for the collection of storm water, thereby avoiding the discharge of the storm water into the treatment plant. This has resulted in the reduction of BOD, COD, total nitrogen and total phosphorus, thus decreasing the efficiency of gas generation. 7 refs., 5 figs., 5 tabs.

Suresh, I.V.; Murthy, M.V.R.L.; Sanghi, S.K.; Yadava, R.N. [Regional Research Lab. (CSIR), Bhopal (India); Wanganeo, A. [Barkatullah Univ., Bhopal (India)

1996-04-01

434

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

E-print Network

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

El-Magboub, Sadek Abdulhafid.

435

Water/Wastewater Treatment Plant Field Device Wiring Method Decision Analysis  

E-print Network

The choice of field device wiring method for water and wastewater treatment plant design is extremely complex and contains many variables. The choice not only affects short-term startup and equipment costs, but also long-term operations...

Dicus, Scott C.

2011-12-16

436

Water Treatment Plant Sludges--An Update of the State of the Art: Part 2.  

ERIC Educational Resources Information Center

This report outlines the state of the art with respect to nonmechanical and mechanical methods of dewatering <