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Sample records for circulating nitrated n-telopeptide

  1. Nitrate in groundwater and N circulation in eastern Botswana

    Science.gov (United States)

    Lagerstedt, E.; Jacks, G.; Sefe, F.

    1994-02-01

    Nitrate pollution due to deep leaching from pit latrines has caused water supply wells in eastern Botswana to exceed health limits concerning nitrate. It was deduced from the estimated intake of salt and protein by the population that, as an average, about 10 percent of the human nitrogen excretion is leached to the groundwater. This fraction was also found in southern India, where on-the-ground excretion is customary. The nitrogen circulation in general in the savanna ecosystem is not appreciably affected in spite of a large livestock density. Overall nitrate leaching is in the order of 1.5 kg N/ha/y, similar to that in another semiarid area in southern India. However, in India, there seems to be a more diffuse areal leaching from agriculture as well as from villages. Measures to minimize the nitrate leaching could be to plant deep-rooted trees adjacent to pit latrines or to use latrines that separate the urine from the faces for a more near-surface infiltration facilitating plant uptake. Measures to minimize leaching will also lessen the rick for bacterial pollution of the groundwater.

  2. Urinary excretion of type I collagen cross-linked N-telopeptides, bone mass and related lifestyle in middle-aged women.

    Directory of Open Access Journals (Sweden)

    Masatomi C

    1999-06-01

    Full Text Available The relationship between past and present lifestyle and urinary excretion of type I collagen cross-linked N-telopeptides (NTx was studied in 61 Japanese females aged 34-59, with a view toward using NTx excretion rates as a predictor of future osteoporosis. Bone mineral density (BMD of the lumbar spine, the speed of sound (SOS and broadband ultrasound attenuation (BUA of the os calcis, urinary NTx, serum osteocalcin (BGP and bone-specific alkaline phosphatase (BAP were measured. Stiffness index (stiffness was calculated from SOS and BUA. The subjects were asked whether they took regular exercise in their childhood and teen years (in elementary, junior-high, senior-high school and college, the past (20-40 years of age and present adulthood. Regular calcium intake, smoking habits, alcohol and other beverage consumption and milk consumption were also covered in the questionnaire. The mean NTx values of premenopausal and postmenopausal group were 22.2 and 56.0 nM bone collagen equivalents (BCE/mM urinary creatinine (Cr, respectively. The group which did not exercise regularly between the ages of 20 and 40 had a higher mean NTx value (40.9 nMBCE/mMCr than the group which did exercise regularly (22.7 nMBCE/mMCr. In multiple regression analyses, age, stiffness and exercise in past adulthood could explain 43.5% of the NTx variance. For prevention of bone metabolic increases around menopause, habitual exercise in early adulthood seems to be effective.

  3. Nitrated type III collagen as a biological marker of nitric oxide-mediated synovial tissue metabolism in osteoarthritis

    DEFF Research Database (Denmark)

    Richardot, P; Charni-Ben Tabassi, N; Toh, L;

    2009-01-01

    OBJECTIVES: Nitric oxide (NO) is a major mediator of joint tissue inflammation and damage in osteoarthritis (OA) and mediates the nitration of tyrosine (Y*) residues in proteins. We investigated the nitration of type III collagen, a major constituent of synovial membrane, in knee OA. METHODS: A...... polyclonal antibody directed against the nitrated QY*DSY*DVKSG sequence from type III collagen N-telopeptide was generated. Synovial tissues from patients with knee OA (n=4) and rheumatoid arthritis (RA, n=4) were analyzed by immunohistochemistry for IIINys. Serum IIINys levels were measured by enzyme......-linked immunosorbent assay in 87 patients with painful knee OA (mean age: 63.0+/-8.0 years, Kellgren-Lawrence score II-III) and in 40 sex and age-matched healthy controls. RESULTS: Competition experiments using various nitrated and un-nitrated type III collagen and derived sequences, showed that the antibody was...

  4. TMSR硝酸盐自然循环回路控制系统设计%Design of nitrate natural circulation loop control system in TMSR

    Institute of Scientific and Technical Information of China (English)

    张宁; 郭冰; 韩立欣; 周大勇

    2015-01-01

    Background: Nitrate natural circulation loop (NNCL) is one of experimental platform in thorium-based molten salt reactor (TMSR), which was designed to study the heat transfer behavior and corrosion behavior of direct reactor auxiliary cooling system (DRACS).Purpose: This study aims to implement a distributed control system (DCS) with functionalities of system control, online state monitor and experimental data acquisition in NNCL. Methods: An experimental physics and industrial control system (EPICS) based distributed control system was designed for this project. An optimized support module structure was designed for I/O operation with low-level PLCs to improve the performance of input/output controller (IOC) runtime database, and a PostgreSQL database was employed for data archive by RDB ChannelArchiver. A control system studio (CSS) interface and MATLAB was implemented in operator interface (OPI) computers, for visual operation and experimental data calculation.Results: Testing for online operation and history data acquisition in OPI interface proved that the control system satisfied all requirements of NNCL control and state monitor with long-term effective.Conclusion: The system could provide efficient and reliable routine for online operation and would well support advanced study of DRACS on this NNCL platform.%为了对硝酸盐自然循环回路(Nitrate Natural Circulation Loop, NNCL)的各子系统及设备的运行状态进行在线监测及远程控制,设计并实现了具有分布式结构的控制系统,并根据工程实际对其软件模块进行了改进。主要包括对过程控制软件包进行结构优化,以提高多通道模式下数据传输效率;使用PostgreSQL关系型数据库取代本地数据存储方式进行数据存档管理和和查询;在操作员计算机中更新人机界面软件以获得更好的界面效果,配置MATLAB在线驱动接口用于数据在线处理。经过运行测试表明,此系统可长期有

  5. Fetal Circulation

    Science.gov (United States)

    ... Pressure High Blood Pressure Tools & Resources Stroke More Fetal Circulation Updated:Jul 8,2016 click to enlarge The ... fetal heart. These two bypass pathways in the fetal circulation make it possible for most fetuses to survive ...

  6. Modeled Wet Nitrate Deposition

    Data.gov (United States)

    U.S. Environmental Protection Agency — Modeled data on nitrate wet deposition was obtained from Dr. Jeff Grimm at Penn State Univ. Nitrate wet depostion causes acidification and eutrophication of surface...

  7. Nitrate accumulation in spinach

    NARCIS (Netherlands)

    Steingröver, Eveliene Geertruda

    1986-01-01

    Leafy vegetables, like spinach, may contain high concentrations of nitrate. In the Netherlands, about 75% of mean daily intake of nitrate orginates from the consumption of vegatables. Hazards to human health are associated with the reduction of nitrate to nitrite. Acute nitrite poisoning causes meth

  8. Nearshore circulation

    NARCIS (Netherlands)

    Battjes, J.A.; Sobey, R.J.; Stive, M.J.F.

    1990-01-01

    Shelf circulation is driven primarily by wind- and tide-induced forces. It is laterally only weakly constrained so that the geostrophic (Coriolis) acceleration is manifest in the response. Nearshore circulation on the other hand is dominated by wave-induced forces associated with shallow-water. wave

  9. 33 CFR 126.28 - Ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate...

    Science.gov (United States)

    2010-07-01

    ... nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate; general provisions. 126.28 Section 126..., ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo nitrate; general provisions. (a) When any item of ammonium nitrate, ammonium nitrate fertilizers, fertilizer mixtures, or nitro carbo...

  10. Preformed Nitrate in the Glacial North Atlantic

    Science.gov (United States)

    Homola, K.; Spivack, A. J.; D'Hondt, S.; Estes, E. R.; Insua, T. L.; McKinley, C. C.; Murray, R. W.; Pockalny, R. A.; Robinson, R. S.; Sauvage, J.

    2015-12-01

    Atmospheric CO2 abundances are highly correlated with global temperature variations over the past 800,000 years. Consequently, understanding the feedbacks between climate and CO2 is important for predictions of future climate. Leading hypotheses to explain this feedback invoke changes in ocean biology, circulation, chemistry, and/or gas exchange rates to trap CO2 in the deep ocean, thereby reducing the greenhouse effect of CO2 in the atmosphere. To test these hypotheses, we use sediment pore water profiles of dissolved nitrate and oxygen to reconstruct paleo-preformed nitrate concentrations at two deep-water sites in the western North Atlantic (23°N 57°W, 5557 m water depth; 30°N 58°W, 5367 m water depth). Preformed nitrate increases down-core to 22.7 μM (25.6 m core depth) at the northern site, and to 28.5 μM (27.8 m core depth) at the southern site. The large preformed nitrate gradient between these sites reveals a paleo-boundary between a southern water source high in preformed nitrate and a northern water source with lower concentrations, similar to today's ocean. However, the boundary between these water masses occurs north of where their modern counterparts meet, indicating that Antarctic Bottom Water (AABW) extended farther north during the Last Glacial Maximum (LGM). In addition, the southern source had a higher preformed nitrate concentration than today's AABW (25 μM), contradicting hypotheses that nutrient utilization was more efficient in the Southern Ocean deep-water formation regions during the LGM. Comparison to our previous Pacific data reveals that the average preformed nitrate concentration of the deep ocean was slightly higher during the LGM than today. This result implies that the CO2-climate feedback was not principally due to more efficient nitrate utilization.

  11. Field determination of nitrate using nitrate reductase

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, E.R.; Corrigan, J.S.; Campbell, W.H. [Nitrate Elimination Co., Inc., Lake Linden, MI (United States)

    1997-12-31

    Nitrate is routinely measured in a variety of substrates - water, tissues, soils, and foods - both in the field and in laboratory settings. The most commonly used nitrate test methods involve the reduction of nitrate to nitrite via a copper-cadmium reagent, followed by reaction of the nitrite with the Griess dye reagents. The resulting color is translated into a nitrate concentration by comparison with a calibrated color chart or comparator, or by reading the absorbance in a spectrophotometer. This basic method is reliable and sufficiently sensitive for many applications. However, the cadmium reagent is quite toxic. The trend today is for continued increase in concern for worker health and safety; in addition, there are increasing costs and logistical problems associated with regulatory constraints on transport and disposal of hazardous materials. Some suppliers have substituted a zinc-based reagent powder for the cadmium in an effort to reduce toxicity. We describe here an enzyme-based nitrate detection method as an improvement on the basic Griess method that demonstrates equal or superior sensitivity, superior selectivity, and is more environmentally benign. Comparisons between the enzyme-based method and some standard field test kits being used today are made.

  12. Agricultural nitrate pollution

    DEFF Research Database (Denmark)

    Anker, Helle Tegner

    2015-01-01

    Despite the passing of almost 25 years since the adoption of the EU Nitrates Directive, agricultural nitrate pollution remains a major concern in most EU Member States. This is also the case in Denmark, although a fairly strict regulatory regime has resulted in almost a 50 per cent reduction...

  13. Circulation economics

    DEFF Research Database (Denmark)

    Ingebrigtsen, Stig; Jakobsen, Ove

    2006-01-01

    presupposes a perspective integrating economic, natural and cultural values. Third, to organize the interplay between all stakeholders we introduce an arena for communicative cooperation. Originality/value - The paper concludes that circulation economics presupposes a change in paradigm, from a mechanistic...

  14. Protein tyrosine nitration

    Science.gov (United States)

    Chaki, Mounira; Leterrier, Marina; Barroso, Juan B

    2009-01-01

    Nitric oxide metabolism in plant cells has a relative short history. Nitration is a chemical process which consists of introducing a nitro group (-NO2) into a chemical compound. in biological systems, this process has been found in different molecules such as proteins, lipids and nucleic acids that can affect its function. This mini-review offers an overview of this process with special emphasis on protein tyrosine nitration in plants and its involvement in the process of nitrosative stress. PMID:19826215

  15. Thermochemical nitrate reduction

    International Nuclear Information System (INIS)

    A series of preliminary experiments was conducted directed at thermochemically converting nitrate to nitrogen and water. Nitrates are a major constituent of the waste stored in the underground tanks on the Hanford Site, and the characteristics and effects of nitrate compounds on stabilization techniques must be considered before permanent disposal operations begin. For the thermochemical reduction experiments, six reducing agents (ammonia, formate, urea, glucose, methane, and hydrogen) were mixed separately with ∼3 wt% NO3- solutions in a buffered aqueous solution at high pH (13); ammonia and formate were also mixed at low pH (4). Reactions were conducted in an aqueous solution in a batch reactor at temperatures of 200 degrees C to 350 degrees C and pressures of 600 to 2800 psig. Both gas and liquid samples were analyzed. The specific components analyzed were nitrate, nitrite, nitrous oxide, nitrogen, and ammonia. Results of experimental runs showed the following order of nitrate reduction of the six reducing agents in basic solution: formate > glucose > urea > hydrogen > ammonia ∼ methane. Airnmonia was more effective under acidic conditions than basic conditions. Formate was also effective under acidic conditions. A more thorough, fundamental study appears warranted to provide additional data on the mechanism of nitrate reduction. Furthermore, an expanded data base and engineering feasibility study could be used to evaluate conversion conditions for promising reducing agents in more detail and identify new reducing agents with improved performance characteristics

  16. Nitrates and nitrites intoxications’ management

    OpenAIRE

    Alexandra Trif

    2007-01-01

    The study pointed out the major sources for clinical and subclinical intoxications with nitrates/nitrites (drinking water and nitrates containing fertilizers), circumstances that determine fertilizers to became sources of intoxication (excessive fertilization/consecutive high level of nitrates in fodders, free access of animals to the fertilizers, administration into the diet instead of natrium chloride), factors that determine high nitrates accumulation in fodders despite optimal fertilizati...

  17. Nitrate in drinking water

    DEFF Research Database (Denmark)

    Schullehner, Jörg; Hansen, Birgitte; Sigsgaard, Torben

    Annual nationwide exposure maps for nitrate in drinking water in Denmark from the 1970s until today will be presented based on the findings in Schullehner & Hansen (2014) and additional work on addressing the issue of private well users and estimating missing data. Drinking water supply in Denmark...... is highly decentralized and fully relying on simple treated groundwater. At the same time, Denmark has an intensive agriculture, making groundwater resources prone to nitrate pollution. Drinking water quality data covering the entire country for over 35 years are registered in the public database Jupiter....... In order to create annual maps of drinking water quality, these data had to be linked to 2,852 water supply areas, which were for the first time digitized, collected in one dataset and connected to the Jupiter database. Analyses of the drinking water quality maps showed that public water supplies...

  18. Potential of dietary nitrate in angiogenesis

    Institute of Scientific and Technical Information of China (English)

    Christos; Rammos; Peter; Luedike; Ulrike; Hendgen-Cotta; Tienush; Rassaf

    2015-01-01

    Endothelial dysfunction with impaired bioavailability of nitric oxide(NO) is the hallmark in the development of cardiovascular disease. Endothelial dysfunction leads to atherosclerosis, characterized by chronic inflammation of the arterial wall and stepwise narrowing of the vessel lumen. Atherosclerosis causes deprivation of adequate tissue blood flow with compromised oxygen supply. To overcome this undersupply, remodeling of the vascular network is necessary to reconstitute and sustain tissue viability. This physiological response is often not sufficient and therapeutic angiogenesis remains an unmet medical need in critical limb ischemia or coronary artery disease. Feasible approaches to promote blood vessel formation are sparse. Administration of pro-angiogenic factors, gene therapy, or targeting of micro RNAs has not yet entered the daily practice. Nitric oxide is an important mediator of angiogenesis that becomes limited under ischemic conditions and the maintenance of NO availability might constitute an attractive therapeutic target. Until recently it was unknown how the organism provides NO under ischemia. In recent years it could be demonstrated that NO can be formed independently of its enzymatic synthesis in the endothelium by reduction of inorganic nitrite under hypoxic conditions. Circulating nitrite derives from oxidation of NO or reduction of inorganic nitrate by commensal bacteria in the oral cavity. Intriguingly, nitrate is a common constituent of our everyday diet and particularly high concentrations are found in leafy green vegetables such as spinach, lettuce, or beetroot. Evidence suggests that dietary nitrate supplementation increases the regenerative capacity of ischemic tissue and that this effect may offer an attractive nutrition-based strategy to improve ischemia-induced revascularization. We here summarize and discuss the regenerative capacity of dietary nitrate on the vascular system.

  19. Nitrates and nitrites intoxications’ management

    Directory of Open Access Journals (Sweden)

    Alexandra Trif

    2007-12-01

    Full Text Available The study pointed out the major sources for clinical and subclinical intoxications with nitrates/nitrites (drinking water and nitrates containing fertilizers, circumstances that determine fertilizers to became sources of intoxication (excessive fertilization/consecutive high level of nitrates in fodders, free access of animals to the fertilizers, administration into the diet instead of natrium chloride, factors that determine high nitrates accumulation in fodders despite optimal fertilization (factors related to the plants, soil, clime, harvest methods, storage, agrotechnical measures, nitrates/nitrites toxicity (over 45 ppm nitrates in drinking water, over 0.5 g nitrate/100 g D.M fodder/diet, the factors that influence nitrates/nitrites toxicity ( species, age, rate of feeding, diet balance especially energetically, pathological effects and symptoms (irritation and congestions on digestive tract, resulting diarrhoea, transformation of hemoglobin into methemoglobin determining severe respiratory insufficiency, vascular collapse, low blood pressure inthe acute nitrates intoxication; hypotiroidism, hypovitaminosis A, reproductive disturbances(abortion, low rate of fertility, dead born offspring, diarrhoea and/or respiratory insufficiency in new born e.g. calves, immunosuppression, decrease of milk production in chronic intoxication. There were presented some suggestions concerning management practices to limit nitrate intoxication (analyze of nitrates/nitrites in water and fodders, good management of the situation of risk ,e .g. dilution of the diet with low nitrate content fodders, feeding with balanced diet in energy, protein, minerals and vitamins, accommodation to high nitrate level diet, avoid grazing one week after a frost period, avoid feeding chop green fodders stored a couple of days, monitoring of health status of animals fed with fodders containing nitrates at risk level, a.o..

  20. Stability and Reproducibility of the Measurement of Plasma Nitrate in Large Epidemiologic Studies.

    Science.gov (United States)

    Wang, Yushan; Townsend, Mary K; Eliassen, A Heather; Wu, Tianying

    2013-04-01

    Inorganic nitrate has emerged as a therapeutic agent for cardiovascular disease; however, nitrate can also metabolize to carcinogenic nitrosamines under pathologic conditions. Few large epidemiologic studies have examined circulating levels of nitrate in relation to cardiovascular disease and cancer. Data on the validity of nitrate measurement in blood samples collected in typical epidemiologic settings are needed before nitrate can be evaluated as an exposure in large epidemiologic studies. We measured plasma levels of nitrate in three pilot studies to evaluate its laboratory variability, stability with delayed processing, and reproducibility over time among women from the Nurses' Health Study and healthy female volunteers. Laboratory variability of nitrate levels was fairly low, with a coefficient variation (CV) of 7%. Plasma nitrate levels in samples stored as whole blood on ice for up to 48 hrs before processing were very stable; the overall intra-class correlation (ICC) from 0 to 48 hours was 0.89 (95%CI, 0.70-0.97). The within-person reproducibility over a one-year period was modest, with an ICC of 0.49 (95% CI, 0.33- 0.94). Our results indicate that measurement of nitrate in plasma is reliable and stable in blood samples with delayed processing up to 48 hours. Within-person reproducibility was modest but data from this study can be used for measurement error correction in subsequent analyses. The measurement of nitrate cannot be widely used in epidemiologic research without the documentation of its stability and reproducibility. PMID:24244804

  1. Plasma levels of N-telopeptide of Type I collagen in periodontal health, disease and after treatment

    Directory of Open Access Journals (Sweden)

    Ganganna Aruna

    2016-01-01

    Conclusion: Within the limits of this study, it may be suggested that plasma NTx levels may provide distinguishing data between periodontally healthy diseased sites and after nonsurgical therapy of diseased sites.

  2. Deep ocean biogeochemistry of silicic acid and nitrate

    Science.gov (United States)

    Sarmiento, J. L.; Simeon, J.; Gnanadesikan, A.; Gruber, N.; Key, R. M.; Schlitzer, R.

    2007-03-01

    Observations of silicic acid and nitrate along the lower branch of the global conveyor belt circulation show that silicic acid accumulation by diatom opal dissolution occurs at 6.4 times the rate of nitrate addition by organic matter remineralization. The export of opal and organic matter from the surface ocean occurs at a Si:N mole ratio that is much smaller than this almost everywhere (cf. Sarmiento et al., 2004). The preferential increase of silicic acid over nitrate as the deep circulation progresses from the North Atlantic to the North Pacific is generally interpreted as requiring deep dissolution of opal together with shallow remineralization of organic matter (Broecker, 1991). However, Sarmiento et al. (2004) showed that the primary reason for the low silicic acid concentration of the upper ocean is that the waters feeding the main thermocline from the surface Southern Ocean are depleted in silicic acid relative to nitrate. By implication, the same Southern Ocean processes that deplete the silicic acid in the surface Southern Ocean must also be responsible for the enhanced silicic acid concentration of the deep ocean. We use observations and results from an updated version of the adjoint model of Schlitzer (2000) to confirm that this indeed the case.

  3. Bone turnover and mineral density in adult thalassemic patients: relationships with growth hormone secretory status and circulating somatomedins.

    Science.gov (United States)

    Scacchi, Massimo; Danesi, Leila; Cattaneo, Agnese; Sciortino, Giovanna; Radin, Raffaella; Ambrogio, Alberto Giacinto; Vitale, Giovanni; D'Angelo, Emanuela; Mirra, Nadia; Zanaboni, Laura; Arvigo, Marica; Boschetti, Mara; Ferone, Diego; Marzullo, Paolo; Baldini, Marina; Cassinerio, Elena; Cappellini, Maria Domenica; Persani, Luca; Cavagnini, Francesco

    2016-08-01

    Previous evidence supports a role for growth hormone (GH)-insulin-like growth factor (IGF)-I deficiency in the pathophysiology of osteopenia/osteoporosis in adult thalassemia. Moreover, serum IGF-II has never been studied in this clinical condition. Thus, we elected to study the GH secretory status and the levels of circulating somatomedins, correlating these parameters with bone mineral density (BMD) and biochemical markers of bone turnover. A hundred and thirty-nine normal weight adult thalassemic patients (72 men and 67 women) were studied. Lumbar and femoral neck BMD were measured in 106/139 patients. Sixty-eight patients underwent growth hormone releasing hormone plus arginine testing. Measurement of baseline IGF-I and IGF-II was performed in all patients, while osteocalcin, C-terminal telopeptide of type I collagen (CTx), and urinary cross-linked N-telopeptides of type I collagen (NTx) were assayed in 95 of them. Femoral and lumbar osteoporosis/Z score below the expected range for age were documented in 61.3 and in 56.6 % of patients, respectively. Severe GH deficiency (GHD) was demonstrated in 27.9 % of cases, whereas IGF-I SDS was low in 86.3 %. No thalassemic patients displayed circulating levels of IGF-II below the reference range. GH peaks were positively correlated with femoral, but not lumbar, Z score. No correlations were found between GH peaks and osteocalcin, CTx and NTx. GH peaks were positively correlated with IGF-I values, which in their turn displayed a positive correlation with osteocalcin, CTx, and NTx. No correlations emerged between IGF-I values and either femoral or lumbar Z scores. No correlations were found between IGF-II and any of the following parameters: GH peaks, osteocalcin, CTx, NTx, femoral Z score, and lumbar Z score. Our study, besides providing for the first time evidence of a normal IGF-II production in thalassemia, contributes to a better understanding of the involvement of the somatotropin-somatomedin axis in the

  4. Nitrate storage and dissimilatory nitrate reduction by eukaryotic microbes

    DEFF Research Database (Denmark)

    Kamp, Anja; Høgslund, Signe; Risgaard-Petersen, Nils;

    2015-01-01

    The microbial nitrogen cycle is one of the most complex and environmentally important element cycles on Earth and has long been thought to be mediated exclusively by prokaryotic microbes. Rather recently, it was discovered that certain eukaryotic microbes are able to store nitrate intracellularly...... and use it for dissimilatory nitrate reduction in the absence of oxygen. The paradigm shift that this entailed is ecologically significant because the eukaryotes in question comprise global players like diatoms, foraminifers, and fungi. This review article provides an unprecedented overview of nitrate...... storage and dissimilatory nitrate reduction by diverse marine eukaryotes placed into an eco-physiological context. The advantage of intracellular nitrate storage for anaerobic energy conservation in oxygen-depleted habitats is explained and the life style enabled by this metabolic trait is described...

  5. Simultaneous nitrification and denitrification based on internal circulation baffled reactor

    Directory of Open Access Journals (Sweden)

    LU Xiaoya

    2014-06-01

    Full Text Available Nitrogen removal experiments were carried out by using an internal circulation baffled bioreactor (ICBBR. Nitrate, nitrite and ammonia were used as N source for nitrogen removal experiments. The ICBBR has high nitrogen removal capacity. The removal rates of total nitrogen, nitrate, and nitrite are almost the same. When nitrate and nitrite were used as N sources their kinetic orders were 0.88. When ammonia was used as N source simultaneous nitrification and denitrification (SND was realized in ICBBR and ammonia removal fitted also 0.88 order kinetics, but total nitrogen removal fitted third-order kinetics. Nitrate and nitrite removal rates were faster than ammonia removal rate under the same C/N ratio, and total nitrogen removal rate increased with increasing C/N ratio.

  6. Evaluation of nitrate destruction methods

    International Nuclear Information System (INIS)

    A wide variety of high nitrate-concentration aqueous mixed [radioactive and Resource Conservation and Recovery Act (RCRA) hazardous] wastes are stored at various US Department of Energy (DOE) facilities. These wastes will ultimately be solidified for final disposal, although the waste acceptance criteria for the final waste form is still being determined. Because the nitrates in the wastes will normally increase the volume or reduce the integrity of all of the waste forms under consideration for final disposal, nitrate destruction before solidification of the waste will generally be beneficial. This report describes and evaluates various technologies that could be used to destroy the nitrates in the stored wastes. This work was funded by the Department of Energy's Office of Technology Development, through the Chemical/Physical Technology Support Group of the Mixed Waste Integrated Program. All the nitrate destruction technologies will require further development work before a facility could be designed and built to treat the majority of the stored wastes. Several of the technologies have particularly attractive features: the nitrate to ammonia and ceramic (NAC) process produces an insoluble waste form with a significant volume reduction, electrochemical reduction destroys nitrates without any chemical addition, and the hydrothermal process can simultaneously treat nitrates and organics in both acidic and alkaline wastes. These three technologies have been tested using lab-scale equipment and surrogate solutions. At their current state of development, it is not possible to predict which process will be the most beneficial for a particular waste stream

  7. [1-(Carboxymethylcyclohexyl]methanaminium nitrate

    Directory of Open Access Journals (Sweden)

    Elise J. C. de Vries

    2011-02-01

    Full Text Available The title compound, C9H18NO2+·NO3−, is an anhydrous nitrate salt of gabapentin, which is formed serendipitously in the presence of selected non-coordinating metals. The crystal structure involves extensive hydrogen bonding between the –NH3+ and –COOH groups and the nitrate anion.

  8. Excess nitrate loads to coastal waters reduces nitrate removal efficiency

    DEFF Research Database (Denmark)

    Lunau, Mirko; Voss, Maren; Erickson, Matthew;

    2013-01-01

    Terrestrial ecosystems are becoming increasingly nitrogen-saturated due to anthropogenic activities, such as agricultural loading with artificial fertilizer. Thus, more and more reactive nitrogen is entering streams and rivers, primarily as nitrate, where it is eventually transported towards the ...

  9. Microwave circulator design

    CERN Document Server

    Linkhart, Douglas K

    2014-01-01

    Circulator design has advanced significantly since the first edition of this book was published 25 years ago. The objective of this second edition is to present theory, information, and design procedures that will enable microwave engineers and technicians to design and build circulators successfully. This resource contains a discussion of the various units used in the circulator design computations, as well as covers the theory of operation. This book presents numerous applications, giving microwave engineers new ideas about how to solve problems using circulators. Design examples are provided, which demonstrate how to apply the information to real-world design tasks.

  10. Catalyzed reduction of nitrate in aqueous solutions

    International Nuclear Information System (INIS)

    Sodium nitrate and other nitrate salts in wastes is a major source of difficulty for permanent disposal. Reduction of nitrate using aluminum metal has been demonstrated, but NH3, hydrazine, or organic compounds containing oxygen would be advantageous for reduction of nitrate in sodium nitrate solutions. Objective of this seed money study was to determine minimum conditions for reduction. Proposed procedure was batchwise heating of aqueous solutions in closed vessels with monitoring of temperatures and pressures. A simple, convenient apparatus and procedure were demonstrated for observing formation of gaseous products and collecting samples for analyses. The test conditions were 250 degree C and 1000 psi max. Any useful reduction of sodium nitrate to sodium hydroxide as the primary product was not found. The nitrate present at pHs 3 or NH4NO3 is easily decomposed, and the effect of nitromethane at these low pHs was confirmed. When acetic acid or formic acid was added, 21 to 56% of the nitrate in sodium nitrate solutions was reduced by methanol or formaldehyde. With hydrazine and acetic acid, 73 % of the nitrate was decomposed to convert NaNO3 to sodium acetate. With hydrazine and formic acid, 36% of the nitrate was decomposed. If these products are more acceptable for final disposal than sodium nitrate, the reagents are cheap and the conversion conditions would be practical for easy use. Ammonium acetate or formate salts did not significantly reduce nitrate in sodium nitrate solutions

  11. Impacts of Human Activities on the Occurrence of Groundwater Nitrate in an Alluvial Plain: A Multiple Isotopic Tracers Approach

    Institute of Scientific and Technical Information of China (English)

    Zhonghe Pang; Lijuan Yuan; Tianming Huang; Yanlong Kong; Jilai Liu; Yiman Li

    2013-01-01

    Nitrate pollution is a severe problem in areas with intensive agricultural activities.This study focuses on nitrate occurrence and its constraints in a selected alluvial fan using chemical data combined with environmental isotopic tracers (18O,3H,and 15N).Results show that groundwater nitrate in the study area is as high as 258.0 mg/L (hereafter NO3-) with an average of 86.8 mg/L against national drinking water limit of 45 mg/L and a regional baseline value of 14.4 mg/L.Outside of the riparian zone,nitrate occurrence is closely related to groundwater circulation and application of chemical fertilizer.High groundwater nitrate is found in the recharge area,where nitrate enters into groundwater through vertical infiltration,corresponding to high 3H and enriched 18O in the water.In the riparian zone,on the contrary,the fate of groundwater nitrate is strongly affected by groundwater level.Based on two sampling transects perpendicular to the riverbank,we found that the high level of nitrate corresponds to the deeper water table (25 m) near the urban center,where groundwater is heavily extracted.Groundwater nitrate is much lower (<12.4 mg/L) at localities with a shallow water table (5 m),which is likely caused by denitrification in the aquifer.

  12. Mountains and Tropical Circulation

    Science.gov (United States)

    Naiman, Z.; Goodman, P. J.; Krasting, J. P.; Malyshev, S.; Russell, J. L.; Stouffer, R. J.

    2015-12-01

    Observed tropical convection exhibits zonal asymmetries that strongly influence spatial precipitation patterns. The drivers of changes to this zonally-asymmetric Walker circulation on decadal and longer timescales have been the focus of significant recent research. Here we use two state-of-the-art earth system models to explore the impact of earth's mountains on the Walker circulation. When all land-surface topography is removed, the Walker circulation weakens by 33-59%. There is a ~30% decrease in global, large-scale upward vertical wind velocities in the middle of the troposphere, but only minor changes in global average convective mass flux, precipitation, surface and sea-surface temperatures. The zonally symmetric Hadley circulation is also largely unchanged. Following the spatial pattern of changes to large-scale vertical wind velocities, precipitation becomes less focused over the tropics. The weakening of the Walker circulation, but not the Hadley circulation, is similar to the behavior of climate models during radiative forcing experiments: in our simulations, the weakening is associated with changes in vertical wind velocities, rather than the hydrologic cycle. These results indicate suggest that mountain heights may significantly influence the Walker circulation on geologic time scales, and observed changes in tropical precipitation over millions of years may have been forced by changes in tropical orography.

  13. A biological source of oceanic alkyl nitrates

    Science.gov (United States)

    Dahl, E. E.; Lewis, C. B.; Velasco, F. L.; Escobar, C.; Kellogg, D.; Velcamp, M.

    2013-12-01

    Alkyl nitrates are an important component of reactive nitrogen in the troposphere. The oceans are a source of alkyl nitrates to the atmosphere, however the source of alkyl nitrates in the oceans is unknown. It has been demonstrated that the reaction of alkyl peroxy radicals (ROO) with nitric oxide (NO) produces alkyl nitrates in the aqueous phase. We hypothesize that alkyl nitrates may be formed by organisms through the same reaction and therefore biological production could be a source of alkyl nitrates to the troposphere. This work focuses on the production of alkyl nitrates by the diatoms Chaetoceros muelleri and Thalassiosira weisfloggi. Using chemostats, we measure alkyl nitrates formed under nitrate limited conditions. We also use triggers and inhibitors of nitric oxide formation to determine if alkyl nitrate formation is affected by changes in NO production. To date, the rates of production of alkyl nitrates in our cultures, lead us to estimate a production rate on the order of femtomolar/day for C1-C3 alkyl nitrates by diatom species in the equatorial Pacific Ocean. This suggests that diatoms may contribute to the overall ocean source of alkyl nitrates; however, it is possible that other types of phytoplankton, such as cyanobacteria, that are more abundant in the open ocean, may contribute to a greater extent.

  14. Short-Term Effects of a High Nitrate Diet on Nitrate Metabolism in Healthy Individuals

    Directory of Open Access Journals (Sweden)

    Catherine P. Bondonno

    2015-03-01

    Full Text Available Dietary nitrate, through the enterosalivary nitrate-nitrite-NO pathway, can improve blood pressure and arterial stiffness. How long systemic nitrate and nitrite remain elevated following cessation of high nitrate intake is unknown. In 19 healthy men and women, the time for salivary and plasma nitrate and nitrite to return to baseline after 7 days increased nitrate intake from green leafy vegetables was determined. Salivary and plasma nitrate and nitrite was measured at baseline [D0], end of high nitrate diet [D7], day 9 [+2D], day 14 [+7D] and day 21 [+14D]. Urinary nitrite and nitrate was assessed at D7 and +14D. Increased dietary nitrate for 7 days resulted in a more than fourfold increase in saliva and plasma nitrate and nitrite (p < 0.001 measured at [D7]. At [+2D] plasma nitrite and nitrate had returned to baseline while saliva nitrate and nitrite were more than 1.5 times higher than at baseline levels. By [+7D] all metabolites had returned to baseline levels. The pattern of response was similar between men and women. Urinary nitrate and nitrate was sevenfold higher at D7 compared to +14D. These results suggest that daily ingestion of nitrate may be required to maintain the physiological changes associated with high nitrate intake.

  15. Tradeoffs between Maize Silage Yield and Nitrate Leaching in a Mediterranean Nitrate-Vulnerable Zone under Current and Projected Climate Scenarios

    Science.gov (United States)

    Basso, Bruno; Giola, Pietro; Dumont, Benjamin; Migliorati, Massimiliano De Antoni; Cammarano, Davide; Pruneddu, Giovanni; Giunta, Francesco

    2016-01-01

    Future climatic changes may have profound impacts on cropping systems and affect the agronomic and environmental sustainability of current N management practices. The objectives of this work were to i) evaluate the ability of the SALUS crop model to reproduce experimental crop yield and soil nitrate dynamics results under different N fertilizer treatments in a farmer’s field, ii) use the SALUS model to estimate the impacts of different N fertilizer treatments on NO3- leaching under future climate scenarios generated by twenty nine different global circulation models, and iii) identify the management system that best minimizes NO3- leaching and maximizes yield under projected future climate conditions. A field experiment (maize-triticale rotation) was conducted in a nitrate vulnerable zone on the west coast of Sardinia, Italy to evaluate N management strategies that include urea fertilization (NMIN), conventional fertilization with dairy slurry and urea (CONV), and no fertilization (N0). An ensemble of 29 global circulation models (GCM) was used to simulate different climate scenarios for two Representative Circulation Pathways (RCP6.0 and RCP8.5) and evaluate potential nitrate leaching and biomass production in this region over the next 50 years. Data collected from two growing seasons showed that the SALUS model adequately simulated both nitrate leaching and crop yield, with a relative error that ranged between 0.4% and 13%. Nitrate losses under RCP8.5 were lower than under RCP6.0 only for NMIN. Accordingly, levels of plant N uptake, N use efficiency and biomass production were higher under RCP8.5 than RCP6.0. Simulations under both RCP scenarios indicated that the NMIN treatment demonstrated both the highest biomass production and NO3- losses. The newly proposed best management practice (BMP), developed from crop N uptake data, was identified as the optimal N fertilizer management practice since it minimized NO3- leaching and maximized biomass production over

  16. Metal nitrate conversion method, patent application

    NARCIS (Netherlands)

    2008-01-01

    A method for converting a supported metal nitrate into the corresponding supported metal comprises heating the metal nitrate to effect its decomposition under a gas mixture that contains nitric oxide and has an oxygen content of

  17. A Novel Chemical Nitrate Destruction Process

    Energy Technology Data Exchange (ETDEWEB)

    Dziewinski, J.; Marczak, S.

    1999-03-01

    Nitrates represent one of the most significant pollutant discharged to the Baltic Sea by the Sliiamae hydrometallurgical plant. This article contains a brief overview of the existing nitrate destruction technologies followed by the description of a new process developed by the authors. The new chemical process for nitrate destruction is cost effective and simple to operate. It converts the nitrate to nitrogen gas which goes to the atmosphere.

  18. 21 CFR 172.170 - Sodium nitrate.

    Science.gov (United States)

    2010-04-01

    ... Preservatives § 172.170 Sodium nitrate. The food additive sodium nitrate may be safely used in or on specified... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sodium nitrate. 172.170 Section 172.170 Food and... follows: (1) As a preservative and color fixative, with or without sodium nitrite, in smoked,...

  19. Nitrate metabolism in the gromiid microbial universe

    DEFF Research Database (Denmark)

    Høgslund, Signe; Risgaard-Petersen, Nils; Cedhagen, Tomas

    to the findings of eukaryotic mediated nitrate reduction in some foraminifera and diatoms, nitrate respiration in gromiids seems to be mediated by bacterial endosymbionts. The role of endobionts in nitrate accumulating eukaryotes is of fundamental importance for understanding the evolutionary path...

  20. 21 CFR 172.160 - Potassium nitrate.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Potassium nitrate. 172.160 Section 172.160 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Preservatives § 172.160 Potassium nitrate. The food additive potassium nitrate may be safely used as a...

  1. High temperature interaction studies on equimolar nitrate mixture of uranyl nitrate hexahydrate and gadolinium nitrate hexahydrate

    International Nuclear Information System (INIS)

    Rare earths including gadolinium form a sizeable fraction of the fission products in the nuclear fission of fissile material in the reactor. These fission products can interact with uranium dioxide fuel and can form various compounds which can alter the thermal behavior of the fuel. The mixed oxide formed due to the high temperature interactions of mixture of uranyl nitrate hexahydrate (UNH) and gadolinium nitrate hexahydrate (GdNH) has been studied using thermal and X- ray diffraction techniques. The equimolar mixture of UNH and GdNH was prepared by mixing the weighed amount of individual nitrates and grinding gently with mortar and pestle. Thermogravimetry (TG) measurements were carried out by separately heating 100 mg of mixture and individual nitrates at heating rate of 10°C min-1 using Netzsch thermal analyzer (Model No.: STA 409 PC Luxx) in high purity nitrogen atmosphere with a flow rate of 120 mL min-1. The XRD measurement was carried out on a Philips X-ray diffractometer (Model PW1710) using nickel-filtered Cu-Kα radiation

  2. Nitrate Uptake, Nitrate Reductase Distribution and their Relation to Proton Release in Five Nodulated Grain Legumes

    OpenAIRE

    Fan, X. H.; Tang, C; RENGEL, Z.

    2002-01-01

    Nitrate uptake, nitrate reductase activity (NRA) and net proton release were compared in five grain legumes grown at 0·2 and 2 mm nitrate in nutrient solution. Nitrate treatments, imposed on 22‐d‐old, fully nodulated plants, lasted for 21 d. Increasing nitrate supply did not significantly influence the growth of any of the species during the treatment, but yellow lupin (Lupinus luteus) had a higher growth rate than the other species examined. At 0·2 mm nitrate supply, nitrate uptake rates ran...

  3. Nitration of naphthalene and remarks on the mechanism of electrophilic aromatic nitration*

    OpenAIRE

    Olah, George A.; Narang, Subhash C.; Olah, Judith A.

    1981-01-01

    Naphthalene was nitrated with a variety of nitrating agents. Comparison of data with Perrin's electrochemical nitration [Perrin, C. L. (1977) J. Am. Chem. Soc. 99, 5516-5518] shows that nitration of naphthalene gives an α-nitronaphthalene to β-nitronaphthalene ratio that varies between 9 and 29 and is thus not constant. Perrin's data, therefore, are considered to be inconclusive evidence for the proposed one-electron transfer mechanism for the nitration of naphthalene and other reactive aroma...

  4. Gaussian Fibonacci Circulant Type Matrices

    Directory of Open Access Journals (Sweden)

    Zhaolin Jiang

    2014-01-01

    Full Text Available Circulant matrices have become important tools in solving integrable system, Hamiltonian structure, and integral equations. In this paper, we prove that Gaussian Fibonacci circulant type matrices are invertible matrices for n>2 and give the explicit determinants and the inverse matrices. Furthermore, the upper bounds for the spread on Gaussian Fibonacci circulant and left circulant matrices are presented, respectively.

  5. Phase diagram of ammonium nitrate

    Science.gov (United States)

    Dunuwille, M.; Yoo, C. S.

    2014-05-01

    Ammonium Nitrate (AN) has often subjected to uses in improvised explosive devices, due to its wide availability as a fertilizer and its capability of becoming explosive with slight additions of organic and inorganic compounds. Yet, the origin of enhanced energetic properties of impure AN (or AN mixtures) is neither chemically unique nor well understood -resulting in rather catastrophic disasters in the past1 and thereby a significant burden on safety in using ammonium nitrates even today. To remedy this situation, we have carried out an extensive study to investigate the phase stability of AN at high pressure and temperature, using diamond anvil cells and micro-Raman spectroscopy. The present results confirm the recently proposed phase IV-to-IV' transition above 17 GPa2 and provide new constraints for the melting and phase diagram of AN to 40 GPa and 400 °C.

  6. Phase diagram of ammonium nitrate

    International Nuclear Information System (INIS)

    Ammonium Nitrate (AN) has often subjected to uses in improvised explosive devices, due to its wide availability as a fertilizer and its capability of becoming explosive with slight additions of organic and inorganic compounds. Yet, the origin of enhanced energetic properties of impure AN (or AN mixtures) is neither chemically unique nor well understood -resulting in rather catastrophic disasters in the past1 and thereby a significant burden on safety in using ammonium nitrates even today. To remedy this situation, we have carried out an extensive study to investigate the phase stability of AN at high pressure and temperature, using diamond anvil cells and micro-Raman spectroscopy. The present results confirm the recently proposed phase IV-to-IV' transition above 17 GPa2 and provide new constraints for the melting and phase diagram of AN to 40 GPa and 400 °C.

  7. Nitrative Stress Participates in Endothelial Progenitor Cell Injury in Hyperhomocysteinemia

    Science.gov (United States)

    Dong, Yu; Sun, Qi; Liu, Teng; Wang, Huanyuan; Jiao, Kun; Xu, Jiahui; Liu, Xin; Liu, Huirong; Wang, Wen

    2016-01-01

    In order to investigate the role of nitrative stress in vascular endothelial injury in hyperhomocysteinemia (HHcy), thirty healthy adult female Wistar rats were randomly divided into three groups: control, hyperhomocysteinemia model, and hyperhomocysteinemia with FeTMPyP (peroxynitrite scavenger) treatment. The endothelium-dependent dilatation of thoracic aorta in vitro was determined by response to acetylcholine (ACh). The histological changes in endothelium were assessed by HE staining and scanning electron microscopy (SEM). The expression of 3-nitrotyrosine (NT) in thoracic aorta was demonstrated by immunohistochemistry and immunofluorescence, and the number of circulating endothelial progenitor cells (EPCs) was quantified by flow cytometry. Hyperhomocysteinemia caused significant endothelial injury and dysfunction including vasodilative and histologic changes, associated with higher expression of NT in thoracic aorta. FeTMPyP treatment reversed these injuries significantly. Further, the effect of nitrative stress on cultured EPCs in vitro was investigated by administering peroxynitrite donor (3-morpholino-sydnonimine, SIN-1) and peroxynitrite scavenger (FeTMPyP). The roles of nitrative stress on cell viability, necrosis and apoptosis were evaluated with 3-(4,5-dimethylthiazol)-2,5-diphenyl tetrazolium (MTT) assay, lactate dehydrogenase (LDH) release assay and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay, respectively. Also, the phospho-eNOS expression and tube formation in Matrigel of cultured EPCs was detected. Our data showed that the survival of EPCs was much lower in SIN-1 group than in vehicle group, both the apoptosis and necrosis of EPCs were much more severe, and the p-eNOS expression and tube formation in Matrigel were obviously declined. Subsequent pretreatment with FeTMPyP reversed these changes. Further, pretreatment with FeTMPyP reversed homocysteine-induced EPC injury. In conclusion, this study indicates that

  8. Nitrative Stress Participates in Endothelial Progenitor Cell Injury in Hyperhomocysteinemia.

    Science.gov (United States)

    Dong, Yu; Sun, Qi; Liu, Teng; Wang, Huanyuan; Jiao, Kun; Xu, Jiahui; Liu, Xin; Liu, Huirong; Wang, Wen

    2016-01-01

    In order to investigate the role of nitrative stress in vascular endothelial injury in hyperhomocysteinemia (HHcy), thirty healthy adult female Wistar rats were randomly divided into three groups: control, hyperhomocysteinemia model, and hyperhomocysteinemia with FeTMPyP (peroxynitrite scavenger) treatment. The endothelium-dependent dilatation of thoracic aorta in vitro was determined by response to acetylcholine (ACh). The histological changes in endothelium were assessed by HE staining and scanning electron microscopy (SEM). The expression of 3-nitrotyrosine (NT) in thoracic aorta was demonstrated by immunohistochemistry and immunofluorescence, and the number of circulating endothelial progenitor cells (EPCs) was quantified by flow cytometry. Hyperhomocysteinemia caused significant endothelial injury and dysfunction including vasodilative and histologic changes, associated with higher expression of NT in thoracic aorta. FeTMPyP treatment reversed these injuries significantly. Further, the effect of nitrative stress on cultured EPCs in vitro was investigated by administering peroxynitrite donor (3-morpholino-sydnonimine, SIN-1) and peroxynitrite scavenger (FeTMPyP). The roles of nitrative stress on cell viability, necrosis and apoptosis were evaluated with 3-(4,5-dimethylthiazol)-2,5-diphenyl tetrazolium (MTT) assay, lactate dehydrogenase (LDH) release assay and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay, respectively. Also, the phospho-eNOS expression and tube formation in Matrigel of cultured EPCs was detected. Our data showed that the survival of EPCs was much lower in SIN-1 group than in vehicle group, both the apoptosis and necrosis of EPCs were much more severe, and the p-eNOS expression and tube formation in Matrigel were obviously declined. Subsequent pretreatment with FeTMPyP reversed these changes. Further, pretreatment with FeTMPyP reversed homocysteine-induced EPC injury. In conclusion, this study indicates that

  9. Collection of Nitrate in a Denuder

    Directory of Open Access Journals (Sweden)

    Hannah Feig

    2008-01-01

    Full Text Available Data are given for aerosol nitrate (NO3- size distributions in the atmosphere as recorded by a cascade impactor and by an annular denuder. Using this data, our goal is to find the percent of nitrate in the atmosphere that the denuder is able to detect. This requires that we find the size distribution of nitrate that enters the denuder. From these data and calculations, we find that 32.8% of nitrate in the atmosphere can be detected by the denuder. Nitrate was measured to study its affects on seagrass in the Tampa Bay and to compare nitrate levels with seagrass growth and decline. Using a denuder for routine measurements will not allow scientists to accurately compare nitrate data to seagrass levels.

  10. 2-Amino-5-chloropyridinium nitrate

    Directory of Open Access Journals (Sweden)

    Donia Zaouali Zgolli

    2009-11-01

    Full Text Available The title structure, C5H6ClN2+·NO3−, is held together by extensive hydrogen bonding between the NO3− ions and 2-amino-5-chloropyridinium H atoms. The cation–anion N—H...O hydrogen bonds link the ions into a zigzag- chain which develops parallel to the b axis. The structure may be compared with that of the related 2-amino-5-cyanopyridinium nitrate.

  11. Electrolytic production of uranous nitrate

    International Nuclear Information System (INIS)

    Efficient production of uranous nitrate is important in nuclear fuel reprocessing because U(IV) acts as a plutonium reductant in solvent extraction and can be coprecipitated with plutonium and/or throium as oxalates during fuel reprocessing. Experimental conditions are described for the efficient electrolytic production of uranous nitrate for use as a reductant in the SRP Purex process. The bench-scale, continuous-flow, electrolysis cell exhibits a current efficiency approaching 100% in combination with high conversion rates of U(VI) to U(IV) in simulated and actual SRP Purex solutions. High current efficiency is achieved with a voltage-controlled mercury-plated platinum electrode and the use of hydrazine as a nitrite scavenger. Conversion of U(VI) to U(IV) proceeds at 100% efficiency. Cathodic gas generation is minimal. The low rate of gas generation permits a long residence time within the cathode, a necessary condition for high conversions on a continuous basis. Design proposals are given for a plant-scale, continuous-flow unit to meet SRP production requirements. Results from the bench-scale tests indicate that an 8-kW unit can supply sufficient uranous nitrate reductant to meet the needs of the Purex process at SRP

  12. 49 CFR 176.415 - Permit requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers.

    Science.gov (United States)

    2010-10-01

    ... nitrates, and certain ammonium nitrate fertilizers. 176.415 Section 176.415 Transportation Other... requirements for Division 1.5, ammonium nitrates, and certain ammonium nitrate fertilizers. (a) Except as... Captain of the Port (COTP). (1) Ammonium nitrate UN1942, ammonium nitrate fertilizers containing more...

  13. Circulant Double Coverings of a Circulant Graph of Valency Five

    Institute of Scientific and Technical Information of China (English)

    Rong Quan FENG; Jin Ho KWAK

    2007-01-01

    Enumerating the isomorphism classes of several types of graph covering projections is one of the central research topics in enumerative topological graph theory. A covering of G is called circulant if its covering graph is circulant. Recently, the authors [Discrete Math., 277, 73-85 (2004)]enumerated the isomorphism classes of circulant double coverings of a certain type, called a typicalcovering, and showed that no double covering of a circulant graph of valency three is circulant. Also, in [Graphs and Combinatorics, 21, 386-400 (2005)], the isomorphism classes of circulant double coverings of a circulant graph of valency four are enumerated. In this paper, the isomorphism classes of circulant double coverings of a circulant graph of valency five are enumerated.

  14. Sensitivity of nitrate aerosols to ammonia emissions and to nitrate chemistry: implications for present and future nitrate optical depth

    Directory of Open Access Journals (Sweden)

    F. Paulot

    2015-09-01

    Full Text Available We update and evaluate the treatment of nitrate aerosols in the Geophysical Fluid Dynamics Laboratory (GFDL atmospheric model (AM3. Accounting for the radiative effects of nitrate aerosols generally improves the simulated aerosol optical depth, although nitrate concentrations at the surface are biased high. This bias can be reduced by increasing the deposition of nitrate to account for the near-surface volatilization of ammonium nitrate or by neglecting the heterogeneous production of nitric acid to account for the inhibition of N2O5 reactive uptake at high nitrate concentrations. Globally, uncertainties in these processes can impact the simulated nitrate optical depth by up to 25 %, much more than the impact of uncertainties in the seasonality of ammonia emissions (6 % or in the uptake of nitric acid on dust (13 %. Our best estimate for present-day fine nitrate optical depth at 550 nm is 0.006 (0.005–0.008. We only find a modest increase of nitrate optical depth (2 (−40 % and ammonia (+38 % from 2010 to 2050. Nitrate burden is projected to increase in the tropics and in the free troposphere, but to decrease at the surface in the midlatitudes because of lower nitric acid concentrations. Our results suggest that better constraints on the heterogeneous chemistry of nitric acid on dust, on tropical ammonia emissions, and on the transport of ammonia to the free troposphere are needed to improve projections of aerosol optical depth.

  15. PULMONARY CIRCULATION AT EXERCISE

    OpenAIRE

    R. Naeije; CHESLER, N

    2012-01-01

    The pulmonary circulation is a high flow and low pressure circuit, with an average resistance of 1 mmHg.min.L−1 in young adults, increasing to 2.5 mmHg.min.L−1 over 4–6 decades of life. Pulmonary vascular mechanics at exercise are best described by distensible models. Exercise does not appear to affect the time constant of the pulmonary circulation or the longitudinal distribution of resistances. Very high flows are associated with high capillary pressures, up to a 20–25 mmHg threshold associ...

  16. Sensitivity of nitrate aerosols to ammonia emissions and to nitrate chemistry: implications for present and future nitrate optical depth

    Science.gov (United States)

    Paulot, F.; Ginoux, P.; Cooke, W. F.; Donner, L. J.; Fan, S.; Lin, M.-Y.; Mao, J.; Naik, V.; Horowitz, L. W.

    2016-02-01

    We update and evaluate the treatment of nitrate aerosols in the Geophysical Fluid Dynamics Laboratory (GFDL) atmospheric model (AM3). Accounting for the radiative effects of nitrate aerosols generally improves the simulated aerosol optical depth, although nitrate concentrations at the surface are biased high. This bias can be reduced by increasing the deposition of nitrate to account for the near-surface volatilization of ammonium nitrate or by neglecting the heterogeneous production of nitric acid to account for the inhibition of N2O5 reactive uptake at high nitrate concentrations. Globally, uncertainties in these processes can impact the simulated nitrate optical depth by up to 25 %, much more than the impact of uncertainties in the seasonality of ammonia emissions (6 %) or in the uptake of nitric acid on dust (13 %). Our best estimate for fine nitrate optical depth at 550 nm in 2010 is 0.006 (0.005-0.008). In wintertime, nitrate aerosols are simulated to account for over 30 % of the aerosol optical depth over western Europe and North America. Simulated nitrate optical depth increases by less than 30 % (0.0061-0.010) in response to projected changes in anthropogenic emissions from 2010 to 2050 (e.g., -40 % for SO2 and +38 % for ammonia). This increase is primarily driven by greater concentrations of nitrate in the free troposphere, while surface nitrate concentrations decrease in the midlatitudes following lower concentrations of nitric acid. With the projected increase of ammonia emissions, we show that better constraints on the vertical distribution of ammonia (e.g., convective transport and biomass burning injection) and on the sources and sinks of nitric acid (e.g., heterogeneous reaction on dust) are needed to improve estimates of future nitrate optical depth.

  17. Prospective study of meat intake and dietary nitrates, nitrites, and nitrosamines and risk of adult glioma123

    OpenAIRE

    Michaud, Dominique S.; Holick, Crystal N.; Batchelor, Tracy T.; Giovannucci, Edward; Hunter, David J.

    2009-01-01

    Background: The hypothesis that nitrosamine exposure may increase the risk of glioma has been circulating for several decades, but testing it has been difficult because of the ubiquitous nature of nitrosamine exposure. Diet has been the focus of many studies because it can substantially influence nitrosamine exposure, mostly from the endogenous formation of nitrosamines based on intake of nitrite and nitrate.

  18. Nitrate contamination of groundwater and its countermeasures

    International Nuclear Information System (INIS)

    The inevitable increases of food production and energy consumption with an increase in world population become main causes of an increase of nitrate load to the environment. Although nitrogen is essential for the growth of animal and plant as a constituent element of protein, excessive nitrate load to the environment contaminates groundwater resources used as drinking water and leads to seriously adverse effects on the health of man and livestock. In order to clarify the problem of nitrate contamination of groundwater and search a new trend of technology development from the viewpoint of environment remediation and protection, the present paper has reviewed adverse effects of nitrate on human health, the actual state of nitrogen cycle, several kinds of nitrate sources, measures for reducing nitrate level, etc. (author)

  19. Nitrate contamination of groundwater and its countermeasures

    Energy Technology Data Exchange (ETDEWEB)

    Mitamura, Hisayoshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2003-03-01

    The inevitable increases of food production and energy consumption with an increase in world population become main causes of an increase of nitrate load to the environment. Although nitrogen is essential for the growth of animal and plant as a constituent element of protein, excessive nitrate load to the environment contaminates groundwater resources used as drinking water and leads to seriously adverse effects on the health of man and livestock. In order to clarify the problem of nitrate contamination of groundwater and search a new trend of technology development from the viewpoint of environment remediation and protection, the present paper has reviewed adverse effects of nitrate on human health, the actual state of nitrogen cycle, several kinds of nitrate sources, measures for reducing nitrate level, etc. (author)

  20. Variability of nitrate and phosphate

    Digital Repository Service at National Institute of Oceanography (India)

    Sardessai, S.; Sundar, D.

    as shown in the schedule in table 5.1. Samples were taken at seven stations (M1?M7) in the Mandovi and at five stations in Zuari (Z1?Z5) (Map B). The locations covered a stretch of about 50km in the Mandovi and 52km in the Zuari. Samples were also taken... mangroves, which harbour sediments rich in organic matter (Wafar 1987). Wafar et al. (1997) noted that the dissolved organic nitrates (DON) and dissolved organic phosphates (DOP) Table 5.1 Schedule of sample collection in the Mandovi and Zuari estuaries...

  1. Water Pollution with Nitrates from Agricultural Sources

    OpenAIRE

    FLESERIU A.; OROIAN I.

    2010-01-01

    One of the biggest water pollution problem is created by nitrates resulted from agriculture. This paper is areview aimin to emphasiz the main water pollution problems produced by nitrates in Romania and EU. The excessnitrates can accumulate in soil in several ways. First, manure effluents containing both ammonia and organic forms ofnitrogen. Organic nitrogen can be converted to ammonia in the soil. The ammonia, together with any ammoniafertilizer applied, is converted to nitrate by soil bacte...

  2. Bacterially mediated removal of phosphorus and cycling of nitrate and sulfate in the waste stream of a "zero-discharge" recirculating mariculture system

    OpenAIRE

    M. D. Krom; A. Ben David; E. D. Ingall; Liane G. Benning; S. Clerici; S. Bottrell; C. Davies; N. J. Potts; R. J. G. Mortimer; J. van Rijn

    2014-01-01

    Simultaneous removal of nitrogen and phosphorus by microbial biofilters has been used in a variety of water treatment systems including treatment systems in aquaculture. In this study, phosphorus, nitrate and sulfate cycling in the anaerobic loop of a zero-discharge, recirculating mariculture system was investigated using detailed geochemical measurements in the sludge layer of the digestion basin. High concentrations of nitrate and sulfate, circulating in the overlying water (∼15 mM), were r...

  3. In adenosine A2B knockouts acute treatment with inorganic nitrate improves glucose disposal, oxidative stress and AMPK signaling in the liver

    Directory of Open Access Journals (Sweden)

    Maria ePeleli

    2015-08-01

    Full Text Available Rationale: Accumulating studies suggest that nitric oxide (NO deficiency and oxidative stress are central pathological mechanisms in type 2 diabetes. Recent findings demonstrate therapeutic effects by boosting a nitrate-nitrite-NO pathway, an alternative pathway for NO formation. This study aimed at investigating the acute effects of inorganic nitrate on glucose and insulin signaling in adenosine A2B receptor knockout mice (A2B-/-, a genetic model of impaired metabolic regulation.Methods: Acute effects of nitrate treatment were investigated in aged wild-type (WT and A2B-/- mice. One hour after injection with nitrate or placebo, metabolic regulation was evaluated by glucose and insulin tolerance tests. NADPH oxidase-mediated superoxide production and AMPK phosphorylation were measured in livers obtained from non-treated or glucose-treated mice, with or without prior nitrate injection. Plasma was used to determine insulin resistance (HOMA-IR and NO signaling.Results: A2B-/- displayed increased body weight, reduced glucose clearance and attenuated overall insulin responses compared with age-matched WT. Nitrate treatment increased circulating levels of nitrate, nitrite and cGMP in A2B-/-, and improved glucose clearance. In WT mice, however, nitrate treatment did not influence glucose clearance. HOMA-IR increased following glucose injection in A2B-/-, but remained at basal levels in mice pretreated with nitrate. NADPH oxidase activity in livers from A2B-/-, but not WT mice, was reduced by nitrate. Livers from A2B-/- displayed reduced AMPK phosphorylation compared with WT mice, and this was increased by nitrate treatment. Injection with the anti-diabetic agent metformin induced similar therapeutic effects in the A2B-/- as observed with nitrate. Conclusion: The A2B-/- mouse is a genetic model of metabolic syndrome. Acute treatment with nitrate improved the metabolic profile, at least partly via reduction in oxidative stress and improved AMPK signaling

  4. Trend Analyses of Nitrate in Danish Groundwater

    Science.gov (United States)

    Hansen, B.; Thorling, L.; Dalgaard, T.; Erlandsen, M.

    2012-04-01

    This presentation assesses the long-term development in the oxic groundwater nitrate concentration and nitrogen (N) loss due to intensive farming in Denmark. Firstly, up to 20-year time-series from the national groundwater monitoring network enable a statistically systematic analysis of distribution, trends and trend reversals in the groundwater nitrate concentration. Secondly, knowledge about the N surplus in Danish agriculture since 1950 is used as an indicator of the potential loss of N. Thirdly, groundwater recharge CFC (Chlorofluorocarbon) age determination allows linking of the first two dataset. The development in the nitrate concentration of oxic groundwater clearly mirrors the development in the national agricultural N surplus, and a corresponding trend reversal is found in groundwater. Regulation and technical improvements in the intensive farming in Denmark have succeeded in decreasing the N surplus by 40% since the mid 1980s while at the same time maintaining crop yields and increasing the animal production of especially pigs. Trend analyses prove that the youngest (0-15 years old) oxic groundwater shows more pronounced significant downward nitrate trends (44%) than the oldest (25-50 years old) oxic groundwater (9%). This amounts to clear evidence of the effect of reduced nitrate leaching on groundwater nitrate concentrations in Denmark. Are the Danish groundwater monitoring strategy obtimal for detection of nitrate trends? Will the nitrate concentrations in Danish groundwater continue to decrease or are the Danish nitrate concentration levels now appropriate according to the Water Framework Directive?

  5. Denitration of Uranyl Nitrate Using Tridodecyl Amine

    International Nuclear Information System (INIS)

    Nitrate extraction from uranyl nitrate using extractant tridodecyl amine and paraffin has been carried out. The aim of this research was to prepare uranyl nitrate with low nitrate content (acid deficiency uranyl nitrate/ADUN). ADUN is a raw material for making kernels uranium oxide in a spherical from which cannot easily be broken/cracked. This ADUN was prepared by extracting nitric acid in uranyl nitrate solution with tridodecyl amine (TDA) and paraffin. Nitric acid in uranyl nitrate solution moved into organic phase due to the complex formation with TDA. The aqueous phase was ADUN, it was than analyzed its nitric and uranium contents using titration method. Tree variables were observed, i.e. uranium contents (80-125 g/l), process temperature (50-100 oC) and TDA/Nitrate molar ratio (0.5-1). Experiment results showed that optimum condition accurate at uranium content of 100 g/l, temperature extraction 60-70 oC and TDA to Nitrate molar ratio 0.75-0.80 with an efficiency of 77 %. (author)

  6. Water Pollution with Nitrates from Agricultural Sources

    Directory of Open Access Journals (Sweden)

    FLESERIU A.

    2010-08-01

    Full Text Available One of the biggest water pollution problem is created by nitrates resulted from agriculture. This paper is areview aimin to emphasiz the main water pollution problems produced by nitrates in Romania and EU. The excessnitrates can accumulate in soil in several ways. First, manure effluents containing both ammonia and organic forms ofnitrogen. Organic nitrogen can be converted to ammonia in the soil. The ammonia, together with any ammoniafertilizer applied, is converted to nitrate by soil bacteria in a process called nitrification. Nitrification is importantbecause plants can only use nitrogen as nitrate. It is equally harmful in both, animals and humans.

  7. Nitration of Phenol Catalyzed by Horseradish Peroxidase

    Institute of Scientific and Technical Information of China (English)

    DAI Rong-ji; HUANG Hui; TONG Bin; XIAO Sheng-yuan

    2007-01-01

    Horseradish peroxidase, an acidic peroxidase from the horseradish, is one of the most important enzymes as analytical reagent.The enzymatic nitration of phenol by oxidation of nitrite was studied using horseradish peroxidase in the presence of H2O2.The results showed that nitration occur at 2- and 4- positions of phenol.There were also minor products of hydroquinone and catechol.The influence of various reaction parameters, including pH, organic solvent, and concentration of H2O2, on nitration products were discussed.The best nitration pH was 7.0, and H2O2 should be added to the reaction mixture slowly.

  8. Measurement of isoprene nitrates by GCMS

    Science.gov (United States)

    Mills, Graham P.; Hiatt-Gipson, Glyn D.; Bew, Sean P.; Reeves, Claire E.

    2016-09-01

    According to atmospheric chemistry models, isoprene nitrates play an important role in determining the ozone production efficiency of isoprene; however this is very poorly constrained through observations as isoprene nitrates have not been widely measured. Measurements have been severely restricted largely due to a limited ability to measure individual isoprene nitrate isomers. An instrument based on gas chromatography/mass spectrometry (GCMS) and the associated calibration methods are described for the speciated measurements of individual isoprene nitrate isomers. Five of the primary isoprene nitrates which formed in the presence of NOx by reaction of isoprene with the hydroxyl radical (OH) in the Master Chemical Mechanism are identified using known isomers on two column phases and are fully separated on the Rtx-200 column. Three primary isoprene nitrates from the reaction of isoprene with the nitrate radical (NO3) are identified after synthesis from the already identified analogous hydroxy nitrate. A Tenax adsorbent-based trapping system allows the analysis of the majority of the known hydroxy and carbonyl primary isoprene nitrates, although not the (1,2)-IN isomer, under field-like levels of humidity and showed no impact from typical ambient concentrations of NOx and ozone.

  9. Photochemistry of Nitrate Adsorbed on Mineral Dust

    Science.gov (United States)

    Gankanda, A.; Grassian, V. H.

    2013-12-01

    Mineral dust particles in the atmosphere are often associated with adsorbed nitrate from heterogeneous reactions with nitrogen oxides including HNO3 and NO2. Although nitrate ion is a well-studied chromophore in natural waters, the photochemistry of adsorbed nitrate on mineral dust particles is yet to be fully explored. In this study, wavelength dependence of the photochemistry of adsorbed nitrate on different model components of mineral dust aerosol has been investigated using transmission FTIR spectroscopy. Al2O3, TiO2 and NaY zeolite were used as model systems to represent non-photoactive oxides, photoactive semiconductor oxides and porous materials respectively, present in mineral dust aerosol. In this study, adsorbed nitrate is irradiated with 254 nm, 310 nm and 350 nm narrow band light. In the irradiation with narrow band light, NO2 is the only detectable gas-phase product formed from nitrate adsorbed on Al2O3 and TiO2. The NO2 yield is highest at 310 nm for both Al2O3 and TiO2. Unlike Al2O3 and TiO2, in zeolite, adsorbed nitrate photolysis to nitrite is observed only at 310 nm during narrow band irradiation. Moreover gas phase products were not detected during nitrate photolysis in zeolite at all three wavelengths. The significance of these differences as related to nitrate photochemistry on different mineral dust components will be highlighted.

  10. INTERNAL CIRCULATION ENVELOPES

    CERN Multimedia

    Mail Office

    2001-01-01

    Internal mail envelopes often finish up in large piles in certain offices, thus creating a shortage for other users of the mail service, who would be grateful if everyone with an unused stock could deposit them in their mail box, after attaching them together with an elastic band or a piece of string. The messengers will then collect them so that the Mail Office can put them back in circulation. Thank you for your understanding and collaboration.

  11. Evaluation of nitrates in albanian wines

    Directory of Open Access Journals (Sweden)

    Ariola Morina

    2013-05-01

    Full Text Available Nitrates are important compounds in nature but not desirable if they are present in wine at increased amount. The high level of nitrate is attributed to the use of nitrogen fertilizers in the vineyards. Method of the reactive Gries I and Gries II was used for the determination of nitrates in wine. There were analyzed 45 white wines and 55 red wines produced in 2008 – 2010, as well as wines produced from Albanian grape varieties Shesh i Bardhë and Shesh i Zi in 2009 and 2010, as an authentic wines evidence with denominated origin. From the results of analyses was observed that, in 51 % of white wines was found that the content of nitrates were less than 5 mg/l, in 46% of them the nitrates level goes up to 10 mg/l and only in 3 % of them the amount of nitrates is up to 12 mg/l. None of white wine samples have the content of nitrates over 20 mg/l. In this case there is no doubt for water addition during wine preparation. In regards of red wines, in 34% of them the amount of nitrates is up to 5 mg/l, in 30% of them up to 10 mg/l, while in 26% of them the amount of nitrates is 20 mg/l. Only 10 % of red wines have nitrates content over 20 mg/l which raise dubiety for falsified wines where water and sugar is added in the red marc. The level of nitrates in wines with denominated origin was under 20 mg/L.

  12. Nitrate pollution of a karstic groundwater system

    International Nuclear Information System (INIS)

    The Bohemian karst, an extensive karst area formed by Devonian and Silurian limestone, is located SW of Prague. The largest of the karstic springs discharges in the village of Svaty Jan pod Skalou. With about 19 L/s of average discharge, the spring was formerly an important source of good quality drinking water in the ares. Because of increasing agricultural activity after World War II, both shallow and deep water resources, including the karstic systems, have been contaminated by infiltrating nitrates. The nitrate content of the Svaty Jan spring now varies from 40 mg/L to 60 mg/L. To specify the sources of nitrate pollution and collect sufficient data for possible prediction of future development, an extensive study of the spring was initiated in 1994. Flow dynamics, chemical, and isotopic composition (δ18O in water, δ15N in nitrate) are monitored in the spring and precipitation in the recharge area together with possible sources of nitrates (fertilizers, solutes in soil profile). The spring discharge responds to precipitation events very quickly but with a small amplitude and a low variability in δ18O (∼2 per mille). This reflects the large volume of the karstic system that dumps infiltrating precipitation and the low contribution of the direct discharge component. Even more contrasting is the relation between the low variability of nitrate content and periodic changes in δ15N of nitrate (from 5 per mille to 2 per mille). With regard to the specifics of the karstic groundwater system (piston-like flow) two alternative hypotheses of nitrate generation are suggested: (1) different rates of nitrate production in the recharge area and (2) different sources of nitrate localized along the recharge area. To verify the hypotheses, the record of fertilizer applied in the recharge area was studied together with actual nitrate content and its isotopic composition in deep soil profiles. (author)

  13. Nitrate uptake, nitrate reductase distribution and their relation to proton release in five nodulated grain legumes.

    Science.gov (United States)

    Fan, X H; Tang, C; Rengel, Z

    2002-09-01

    Nitrate uptake, nitrate reductase activity (NRA) and net proton release were compared in five grain legumes grown at 0.2 and 2 mM nitrate in nutrient solution. Nitrate treatments, imposed on 22-d-old, fully nodulated plants, lasted for 21 d. Increasing nitrate supply did not significantly influence the growth of any of the species during the treatment, but yellow lupin (Lupinus luteus) had a higher growth rate than the other species examined. At 0.2 mM nitrate supply, nitrate uptake rates ranged from 0.6 to 1.5 mg N g(-1) d(-1) in the order: yellow lupin > field pea (Pisum sativum) > chickpea (Cicer arietinum) > narrow-leafed lupin (L angustifolius) > white lupin (L albus). At 2 mM nitrate supply, nitrate uptake ranged from 1.7 to 8.2 mg N g(-1) d(-1) in the order: field pea > chickpea > white lupin > yellow lupin > narrow-leafed lupin. Nitrate reductase activity increased with increased nitrate supply, with the majority of NRA being present in shoots. Field pea and chickpea had much higher shoot NRA than the three lupin species. When 0.2 mM nitrate was supplied, narrow-leafed lupinreleased the most H+ per unit root biomass per day, followed by yellow lupin, white lupin, field pea and chickpea. At 2 mM nitrate, narrow-leafed lupin and yellow lupin showed net proton release, whereas the other species, especially field pea, showed net OH- release. Irrespective of legume species and nitrate supply, proton release was negatively correlated with nitrate uptake and NRA in shoots, but not with NRA in roots. PMID:12234143

  14. Dietary Nitrate, Nitric Oxide, and Cardiovascular Health.

    Science.gov (United States)

    Bondonno, Catherine P; Croft, Kevin D; Hodgson, Jonathan M

    2016-09-01

    Emerging evidence strongly suggests that dietary nitrate, derived in the diet primarily from vegetables, could contribute to cardiovascular health via effects on nitric oxide (NO) status. NO plays an essential role in cardiovascular health. It is produced via the classical L-arginine-NO-synthase pathway and the recently discovered enterosalivary nitrate-nitrite-NO pathway. The discovery of this alternate pathway has highlighted dietary nitrate as a candidate for the cardioprotective effect of a diet rich in fruit and vegetables. Clinical trials with dietary nitrate have observed improvements in blood pressure, endothelial function, ischemia-reperfusion injury, arterial stiffness, platelet function, and exercise performance with a concomitant augmentation of markers of NO status. While these results are indicative of cardiovascular benefits with dietary nitrate intake, there is still a lingering concern about nitrate in relation to methemoglobinemia, cancer, and cardiovascular disease. It is the purpose of this review to present an overview of NO and its critical role in cardiovascular health; to detail the observed vascular benefits of dietary nitrate intake through effects on NO status as well as to discuss the controversy surrounding the possible toxic effects of nitrate.

  15. Intravesical silver nitrate for refractory hemorrhagic cystitis

    Science.gov (United States)

    Montgomery, Brian D.; Boorjian, Stephen A.; Ziegelmann, Matthew J.; Joyce, Daniel D.; Linder, Brian J.

    2016-01-01

    Objective Hemorrhagic cystitis is a challenging clinical entity with limited evidence available to guide treatment. The use of intravesical silver nitrate has been reported, though supporting literature is sparse. Here, we sought to assess outcomes of patients treated with intravesical silver nitrate for refractory hemorrhagic cystitis. Material and methods We identified nine patients with refractory hemorrhagic cystitis treated at our institution with intravesical silver nitrate between 2000–2015. All patients had failed previous continuous bladder irrigation with normal saline and clot evacuation. Treatment success was defined as requiring no additional therapy beyond normal saline irrigation after silver nitrate instillation prior to hospital discharge. Results Median patient age was 80 years (IQR 73, 82). Radiation was the most common etiology for hemorrhagic cystitis 89% (8/9). Two patients underwent high dose (0.1%–0.4%) silver nitrate under anesthesia, while the remaining seven were treated with doses from 0.01% to 0.1% via continuous bladder irrigation for a median of 3 days (range 2–4). All nine patients (100%) had persistent hematuria despite intravesical silver nitrate therapy, requiring additional interventions and red blood cell transfusion during the hospitalization. There were no identified complications related to intravesical silver nitrate instillation. Conclusion Although well tolerated, we found that intravesical silver nitrate was ineffective for bleeding control, suggesting a limited role for this agent in the management of patients with hemorrhagic cystitis. PMID:27635296

  16. Dietary Nitrate, Nitric Oxide, and Cardiovascular Health.

    Science.gov (United States)

    Bondonno, Catherine P; Croft, Kevin D; Hodgson, Jonathan M

    2016-09-01

    Emerging evidence strongly suggests that dietary nitrate, derived in the diet primarily from vegetables, could contribute to cardiovascular health via effects on nitric oxide (NO) status. NO plays an essential role in cardiovascular health. It is produced via the classical L-arginine-NO-synthase pathway and the recently discovered enterosalivary nitrate-nitrite-NO pathway. The discovery of this alternate pathway has highlighted dietary nitrate as a candidate for the cardioprotective effect of a diet rich in fruit and vegetables. Clinical trials with dietary nitrate have observed improvements in blood pressure, endothelial function, ischemia-reperfusion injury, arterial stiffness, platelet function, and exercise performance with a concomitant augmentation of markers of NO status. While these results are indicative of cardiovascular benefits with dietary nitrate intake, there is still a lingering concern about nitrate in relation to methemoglobinemia, cancer, and cardiovascular disease. It is the purpose of this review to present an overview of NO and its critical role in cardiovascular health; to detail the observed vascular benefits of dietary nitrate intake through effects on NO status as well as to discuss the controversy surrounding the possible toxic effects of nitrate. PMID:25976309

  17. Effect of ammonium nutrition on the nitrate utilization, nitrate reductase actvity and growth of Spirodela polyrrhiza

    Directory of Open Access Journals (Sweden)

    Ewa Tatkowska

    2014-02-01

    Full Text Available The influence of NH4+ ions on nitrate assimilation and growth of sterile Spirodela polyrrhiza cultures was investigated. S. polyrrhiza utilises both the nitrate and the ammonium form of nitrogen, it prefers, however, NH4+. Ammonium ions present in the nitrate medium inhibit the activity of nitrate reductase (NR, but they do not affect enzyme 'induction and only slightly reduce N03- uptake. These results sugest that the inhibitory effect of NH4+ on the NR activity is the main cause of the decrease in N03- assimilation by S. polyrrhiza cultures growing in nitrate-ammonium medium.

  18. Modelled Circulation In Storfjorden

    Science.gov (United States)

    Skogseth, R.; Asplin, L.

    The model area Storfjorden is situated between the islands Spitsbergen, Barentsöya and Edgeöya at the Svalbard Archipelago. The entrance of Storfjorden is defined by a shallow bank Storfjordbanken and some small islands Tusenöyane in southeast, and by an 115m deep sill at about 76 45' N in the south. Maximum depth in Storfjorden is 190m, which is surrounded by gradually shallower shelves in the north, the east and southeast. A steep bottom slope is present on the western side of Storfjorden. He- leysundet and Freemansundet, two sounds between respectively Spitsbergen and Bar- entsöya, and Barentsöya and Edgeöya, define two narrow and shallow entrances in the north and northeast connecting Storfjorden with the northwestern Barents Sea. Strong tidal currents exist in Heleysundet (4-5ms-1) and Freemansundet (2-3ms-1), but the general circulation in Storfjorden is not well known. The coastal current in Storfjor- den is cyclonic directed into Storfjorden south of Edgeöya from the East Spitsbergen Current and out of Storfjorden south of Spitsbergen where it is called Sørkappstrøm- men. A three-dimensional sigma layered numerical ocean model called Bergen Ocean Model (BOM) was used to simulate the circulation in Storfjorden with Freemansundet opened. Two simulations were carried out, one with heat flux (100 Wm-2) and one without heat flux from the ocean to the atmosphere. The heat flux was applied only in the proper fjord area north of the sill and not outside as a crude approximation of the effects of a polynya in the sea ice cover during winter. Both simulations had a 4km horizontal resolution and 21 sigma layers. The model is forced by winds (from the NCEP reanalyzed fields) and tides. Initial fields are from the DNMI/IMR climatol- ogy. The model simulation without heat flux gave a circulation heavily dependent on tidal forcing, showing strong tidal currents up to 2ms-1 in Freemansundet, between Tusenöyane and on Storfjordbanken southwest of Edgeöya. Earlier

  19. Resolvability in Circulant Graphs

    Institute of Scientific and Technical Information of China (English)

    Muhammad SALMAN; Imran JAVAID; Muhammad Anwar CHAUDHRY

    2012-01-01

    A set W of the vertices of a connected graph G is called a resolving set for G if for every two distinct vertices u,v ∈ V(G) there is a vertex w ∈ W such that d(u,w) ≠ d(v,w).A resolving set of minimum cardinality is called a metric basis for G and the number of vertices in a metric basis is called the metric dimension of G,denoted by dim(G).For a vertex u of G and a subset S of V(G),the distance between u and S is the number mins∈s d(u,s).A k-partition H ={S1,S2,...,Sk} of V(G) is called a resolving partition if for every two distinct vertices u,v ∈ V(G) there is a set Si in Π such that d(u,Si) ≠ d(v,Si).The minimum k for which there is a resolving k-partition of V(G) is called the partition dimension of G,denoted by pd(G).The circulant graph is a graph with vertex set Zn,an additive group ofintegers modulo n,and two vertices labeled i and j adjacent if and only if i - j (mod n) ∈ C,where C C Zn has the property that C =-C and 0(∈) C.The circulant graph is denoted by Xn,△ where A =|C|.In this paper,we study the metric dimension of a family of circulant graphs Xn,3 with connection set C ={1,-n/2,n - 1} and prove that dim(Xn,3) is independent of choice of n by showing that 3 for all n =0 (mod 4),dim(X,n,3) ={ 4 for all n =2 (mod 4).We also study the partition dimension of a family of circulant graphs Xn,4 with connection set C ={±1,±2} and prove that pd(Xn,4) is independent of choice of n and show that pd(X5,4) =5 and 3 forall odd n≥9,pd(Xn,4) ={ 4 for all even n ≥ 6 and n =7.

  20. Nitrate and inhibition of ruminal methanogenesis: microbial ecology, obstacles and opportunities for lowering methane emissions from ruminant livestock

    Directory of Open Access Journals (Sweden)

    Chengjian eYang

    2016-02-01

    Full Text Available Ruminal methane production is among the main targets for greenhouse gas (GHG mitigation for the animal agriculture industry. Many compounds have been evaluated for their efficacy to suppress enteric methane production by ruminal microorganisms. Of these, nitrate as an alternative hydrogen sink has been among the most promising, but it suffers from variability in efficacy for reasons that are not understood. The accumulation of nitrite, which is poisonous when absorbed into the animal’s circulation, is also variable and poorly understood. This review identifies large gaps in our knowledge of rumen microbial ecology that handicap the further development and safety of nitrate as a dietary additive. Three main bacterial species have been associated historically with ruminal nitrate reduction, namely Wolinella succinogenes, Veillonella parvula and Selenomonas ruminantium, but others almost certainly exist in the largely uncultivated ruminal microbiota. Indications are strong that ciliate protozoa can reduce nitrate, but the significance of their role relative to bacteria is not known. The metabolic fate of the reduced nitrate has not been studied in detail. It is important to be sure that nitrate metabolism and efforts to enhance rates of nitrite reduction do not lead to the evolution of the much more potent GHG, nitrous oxide. The relative importance of direct inhibition of archaeal methanogenic enzymes by nitrite or the efficiency of capture of hydrogen by nitrate reduction in lowering methane production is also not known, nor are nitrite effects on other members of the microbiota. How effective would combining mitigation methods be, based on our understanding of the effects of nitrate and nitrite on the microbiome? Answering these fundamental microbiological questions is essential in assessing the potential of dietary nitrate to limit methane emissions from ruminant livestock.

  1. Nitrate and Inhibition of Ruminal Methanogenesis: Microbial Ecology, Obstacles, and Opportunities for Lowering Methane Emissions from Ruminant Livestock.

    Science.gov (United States)

    Yang, Chengjian; Rooke, John A; Cabeza, Irene; Wallace, Robert J

    2016-01-01

    Ruminal methane production is among the main targets for greenhouse gas (GHG) mitigation for the animal agriculture industry. Many compounds have been evaluated for their efficacy to suppress enteric methane production by ruminal microorganisms. Of these, nitrate as an alternative hydrogen sink has been among the most promising, but it suffers from variability in efficacy for reasons that are not understood. The accumulation of nitrite, which is poisonous when absorbed into the animal's circulation, is also variable and poorly understood. This review identifies large gaps in our knowledge of rumen microbial ecology that handicap the further development and safety of nitrate as a dietary additive. Three main bacterial species have been associated historically with ruminal nitrate reduction, namely Wolinella succinogenes, Veillonella parvula, and Selenomonas ruminantium, but others almost certainly exist in the largely uncultivated ruminal microbiota. Indications are strong that ciliate protozoa can reduce nitrate, but the significance of their role relative to bacteria is not known. The metabolic fate of the reduced nitrate has not been studied in detail. It is important to be sure that nitrate metabolism and efforts to enhance rates of nitrite reduction do not lead to the evolution of the much more potent GHG, nitrous oxide. The relative importance of direct inhibition of archaeal methanogenic enzymes by nitrite or the efficiency of capture of hydrogen by nitrate reduction in lowering methane production is also not known, nor are nitrite effects on other members of the microbiota. How effective would combining mitigation methods be, based on our understanding of the effects of nitrate and nitrite on the microbiome? Answering these fundamental microbiological questions is essential in assessing the potential of dietary nitrate to limit methane emissions from ruminant livestock. PMID:26904008

  2. North Atlantic Circulation

    Science.gov (United States)

    Molinari, R.; Bryan, K.; Schott, F.

    The intensity of the North Atlantic winddriven and thermohaline circulation and the close proximity of many oceanographic installations make the North Atlantic a particularly favored region of the world ocean from the standpoint of research in ocean circulation. Recent increases in available data and advances in numerical modeling techniques served as the impetus to convene a joint workshop of modelers and observers working on the North Atlantic with the Scientific Committee on Oceanic Research (SCOR) Working Group (WG) 68 (“North Atlantic Circulation”). Goals of the workshop were to provide an update on data sets and models and to discuss the poleward heat flux problem and possible monitoring strategies. The joint Workshop/SCOR WG-68 meeting was convened by F. Schott (chairman of the working group; Rosenstiel School of Marine and Atmospheric Science, Miami, Fla.), K. Bryan (National Oceanic and Atmospheric Administration/ Geophysical Fluid Dynamics Laboratory (NOAA/GFDL)), and R. Molinari (NOAA/Atlantic Oceanographic and Meteorological Laboratory (NOAA/AOML)).

  3. Circulation of Stars

    Science.gov (United States)

    Boitani, P.

    2016-01-01

    Since the dawn of man, contemplation of the stars has been a primary impulse in human beings, who proliferated their knowledge of the stars all over the world. Aristotle sees this as the product of primeval and perennial “wonder” which gives rise to what we call science, philosophy, and poetry. Astronomy, astrology, and star art (painting, architecture, literature, and music) go hand in hand through millennia in all cultures of the planet (and all use catasterisms to explain certain phenomena). Some of these developments are independent of each other, i.e., they take place in one culture independently of others. Some, on the other hand, are the product of the “circulation of stars.” There are two ways of looking at this. One seeks out forms, the other concentrates on the passing of specific lore from one area to another through time. The former relies on archetypes (for instance, with catasterism), the latter constitutes a historical process. In this paper I present some of the surprising ways in which the circulation of stars has occurred—from East to West, from East to the Far East, and from West to East, at times simultaneously.

  4. Comparative evaluation of nitrate removal technologies

    International Nuclear Information System (INIS)

    Due to the extensive application of artificial nitrogen-based fertilizers and animal manure on land, many water agencies face problems of increasing concentrations of nitrate in groundwater. The contamination of groundwater by nitrate may pose a significant public health problem. The threat of methemoglobinemia is well documented and reflected in the U.S. drinking water standard of 10 mg/L as nitrate-nitrogen. Approximately 45% of Saskatchewan's population use groundwater for drinking purposes, out of which, approximately 23% (230,000) are rural residents. The water used is made available from over 48,000 privately owned wells in regions where there is an extensive application of chemical fertilizers. Biological denitrification, ion exchange and reveres osmosis (RO) processes were selected for further study. Field studies were conducted on these processes. The sulfur/limestone autotrophic denitrification (SLAD) process was selected to achieve biological removal of nitrate from groundwater. The feasibility of the system was evaluated under anaerobic conditions. An ion exchange study was conducted using Ionac A554 which is strong anion exchange resins. In the case of groundwater containing low sulfate concentrations, A554 offered high nitrate removal. However, the disposal of regenerant brine can be a problem. A reverse osmosis unit with Filmtec membrane elements (FT30-Element Family) was used in the study on nitrate removal. The unit effluent average nitrate concentration was less than the maximum allowable concentration. (author)

  5. Microbiological analysis of the in situ bitumen-nitrate-Opalinus clay interaction

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. Clay formations like the Opalinus Clay are foreseen to serve as the host rock for geological disposal of high and intermediate-level long-lived radioactive waste in several countries, because of their favourable properties to delay the migration of radionuclides over time. However, bituminized intermediate-level long-lived radioactive waste may physico-chemically perturb the clay barrier properties because in time it will leach substantial amounts of nitrate and organic bitumen degradation products (BDP). To study the physico-chemical impact of intermediate-level radioactive waste containing bitumen and nitrate, an in situ experiment in the Opalinus Clay (Saint Ursanne, Switzerland) named the Bitumen-Nitrate- Clay interaction (BN) experiment, is being performed at the Mont Terri Rock Laboratory. The in situ equipment of the BN-experiment consists of three separate packed-off intervals, supplied with a filter screen. Each interval is equipped with its own stainless steel water circulation unit. Such water circulation unit contains water sampling containers, circulation pumps and flow meters. One of the circulation units is equipped with an on-line UV spectrophotometer and pH electrode intervals, allowing a continuous monitoring of nitrate, nitrite concentrations, organic carbon level and pH. In a first series of tests, the microbial and biogeochemical effect of a nitrate and/or acetate perturbation is studied. Acetate is used as it a good representation of BDP. Hereto, nitrate was injected in interval 1 while a mixture of nitrate and acetate is injected in interval 2. As an active microbial community can have a significant impact on the physical and (geo)chemical conditions of the clay surrounding the disposal gallery, microbial analyses were performed on samples taken from the interval solutions before, during and after this first series of tests. Our microbial investigations which included Scanning Electron

  6. Ocean General Circulation Models

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Jin-Ho; Ma, Po-Lun

    2012-09-30

    1. Definition of Subject The purpose of this text is to provide an introduction to aspects of oceanic general circulation models (OGCMs), an important component of Climate System or Earth System Model (ESM). The role of the ocean in ESMs is described in Chapter XX (EDITOR: PLEASE FIND THE COUPLED CLIMATE or EARTH SYSTEM MODELING CHAPTERS). The emerging need for understanding the Earth’s climate system and especially projecting its future evolution has encouraged scientists to explore the dynamical, physical, and biogeochemical processes in the ocean. Understanding the role of these processes in the climate system is an interesting and challenging scientific subject. For example, a research question how much extra heat or CO2 generated by anthropogenic activities can be stored in the deep ocean is not only scientifically interesting but also important in projecting future climate of the earth. Thus, OGCMs have been developed and applied to investigate the various oceanic processes and their role in the climate system.

  7. Percutaneous interventions in Fontan circulation

    Directory of Open Access Journals (Sweden)

    Eduardo Franco

    2015-09-01

    Conclusions: Interventional catheterization procedures are often necessary to reach and maintain the fragile Fontan circulation, mainly in patients with right morphology systemic ventricles and fenestrated Fontan conduits.

  8. ROE Wet Nitrate Deposition 1989-1991

    Data.gov (United States)

    U.S. Environmental Protection Agency — The raster data represent the amount of wet nitrate deposition in kilograms per hectare from 1989 to 1991. Summary data in this indicator were provided by EPA’s...

  9. ROE Wet Nitrate Deposition 2011-2013

    Data.gov (United States)

    U.S. Environmental Protection Agency — The raster data represent the amount of wet nitrate deposition in kilograms per hectare from 2011 to 2013. Summary data in this indicator were provided by EPA’s...

  10. Historic nitrate storage in groundwater system - a non-negligible process in nitrate water pollution management

    OpenAIRE

    Wang, Lei; Ward, Robert; Stuart, Marianne

    2014-01-01

    Nitrate water pollution is not only an environmental issue but also a threat to the economy and human health. It remains an international problem and has been identified as a major threat to water quality and the delivery of the EU Water Framework and Nitrates Directives targets. It could take decades for nitrate derived from historic fertiliser application, which leaches into groundwater, to travel through thick unsaturated zones (UZs) and saturated zones, and arrive at rivers and boreho...

  11. Synthesis of a new energetic nitrate ester

    Energy Technology Data Exchange (ETDEWEB)

    Chavez, David E [Los Alamos National Laboratory

    2008-01-01

    Nitrate esters have been known as useful energetic materials since the discovery of nitroglycerin by Ascanio Sobrero in 1846. The development of methods to increase the safety and utility of nitroglycerin by Alfred Nobel led to the revolutionary improvement in the utility of nitroglycerin in explosive applications in the form of dynamite. Since then, many nitrate esters have been prepared and incorporated into military applications such as double-based propellants, detonators and as energetic plasticizers. Nitrate esters have also been shown to have vasodilatory effects in humans and thus have been studied and used for treatments of ailments such as angina. The mechanism of the biological response towards nitrate esters has been elucidated recently. Interestingly, many of the nitrate esters used for military purposes are liquids (ethylene glycol dinitrate, propylene glycol dinitrate, etc). Pentaerythritol tetranitrate (PETN) is one of the only solid nitrate esters, besides nitrocellulose, that is used in any application. Unfortunately, PETN melting point is above 100 {sup o}C, and thus must be pressed as a solid for detonator applications. A more practical material would be a melt-castable explosive, for potential simplification of manufacturing processes. Herein we describe the synthesis of a new energetic nitrate ester (1) that is a solid at ambient temperatures, has a melting point of 85-86 {sup o}C and has the highest density of any known nitrate ester composed only of carbon, hydrogen, nitrogen and oxygen. We also describe the chemical, thermal and sensitivity properties of 1 as well as some preliminary explosive performance data.

  12. Nitrate Adsorption on Clay Kaolin: Batch Tests

    OpenAIRE

    Morteza Mohsenipour; Shamsuddin Shahid; Kumars Ebrahimi

    2015-01-01

    Soils possessing kaolin, gibbsite, goethite, and hematite particles have been found to have a natural capacity to attenuate pollution in aqueous phase. On the other hand, the hydroxyl group in soil increases anion exchange capacity under a low pH condition. The main objective of this paper was to evaluate effects of kaolin on nitrate reduction under acidic condition. In order to analyze the kaolin adsorption behaviour under various conditions, four different concentrations of nitrate, 45, 112...

  13. Nitrate concentrations in the Morestead borehole, Twyford

    OpenAIRE

    Stuart, M.E.; Chilton, P J; Newell, A. J.; Butcher, A.S.

    2008-01-01

    This report describes work carried out at Morestead, Twyford as part of a BGS research project “Nitrate Mass Balance in the Saturated Zone”. The project aimed to evaluate the role of the diffusive exchange of nitrate between fracture water and porewater in the saturated zone of the aquifer. The approach adopted attempted to obtain a mass balance for the catchment to a public supply borehole by comparing nitrogen released from the soil with nitrogen held in the aquifer and nitro...

  14. European Community Measures to Reduce Nitrate Pollution

    OpenAIRE

    Al-hedny, Suhad

    2010-01-01

    Water protection proves to be a difficult task, whether it is dealt with through legislation or the implementation of a process to reduce further pollution. This study considers how the issue of water pollution from nitrates in agricultural practices has become better understood through the reforms of the common agriculture policy (CAP) and the enactment of various regulations and directives by EU. The implementation of the EC Nitrate Directive is a main focus of this study because it was a m...

  15. Phase relations in the lanthanum nitrate (copper nitrate) - poly(vinylpyrrolidone) - water systems

    International Nuclear Information System (INIS)

    Room-temperature isothermal sections of the phase diagrams of lanthanum nitrate-poly(vinylpyrrolidone)-water and copper nitrate-poly(vinylpyrrolidone)-water systems were studied. The following features were found: a wide region of homogeneous water-polymer solutions, liquid-liquid phase separation field, and a three-phase region in which two liquids coexist with salt crystals. In the lanthanum nitrate system, liquid-liquid phase separation has a lower critical solution point (polythermal sections were studied); in the copper nitrate system, it has an upper critical solution point. The type of diagram for unstudied systems is predicted based on the analysis of polymer-salt phase diagrams

  16. The Arabidopsis ATNRT2.7 nitrate transporter controls nitrate content in seeds.

    Science.gov (United States)

    Chopin, Franck; Orsel, Mathilde; Dorbe, Marie-France; Chardon, Fabien; Truong, Hoai-Nam; Miller, Anthony J; Krapp, Anne; Daniel-Vedele, Françoise

    2007-05-01

    In higher plants, nitrate is taken up by root cells where Arabidopsis thaliana NITRATE TRANSPORTER2.1 (ATNRT2.1) chiefly acts as the high-affinity nitrate uptake system. Nitrate taken up by the roots can then be translocated from the root to the leaves and the seeds. In this work, the function of the ATNRT2.7 gene, one of the seven members of the NRT2 family in Arabidopsis, was investigated. High expression of the gene was detected in reproductive organs and peaked in dry seeds. beta-Glucuronidase or green fluorescent protein reporter gene expression driven by the ATNRT2.7 promoter confirmed this organ specificity. We assessed the capacity of ATNRT2.7 to transport nitrate in Xenopus laevis oocytes or when it is expressed ectopically in mutant plants deficient in nitrate transport. We measured the impact of an ATNRT2.7 mutation and found no difference from the wild type during vegetative development. By contrast, seed nitrate content was affected by overexpression of ATNRT2.7 or a mutation in the gene. Finally, we showed that this nitrate transporter protein was localized to the vacuolar membrane. Our results demonstrate that ATNRT2.7 plays a specific role in nitrate accumulation in the seed.

  17. Nitrate Adsorption on Clay Kaolin: Batch Tests

    Directory of Open Access Journals (Sweden)

    Morteza Mohsenipour

    2015-01-01

    Full Text Available Soils possessing kaolin, gibbsite, goethite, and hematite particles have been found to have a natural capacity to attenuate pollution in aqueous phase. On the other hand, the hydroxyl group in soil increases anion exchange capacity under a low pH condition. The main objective of this paper was to evaluate effects of kaolin on nitrate reduction under acidic condition. In order to analyze the kaolin adsorption behaviour under various conditions, four different concentrations of nitrate, 45, 112.5, 225, and 450 mgNO3-/L, with a constant pH equal to 2, constant temperature equal to 25°C, and exposure period varying from 0 to 150 minutes were considered. The capacity of nitrate adsorption on kaolin has also been studied involving two well-known adsorption isotherm models, namely, Freundlich and Longmuir. The results revealed that approximately 25% of the nitrate present in the solution was adsorbed on clay kaolin. The laboratory experimental data revealed that Freundlich adsorption isotherm model was more accurate than Longmuir adsorption model in predicting of nitrate adsorption. Furthermore, the retardation factor of nitrate pollution in saturated zone has been found to be approximately 4 in presence of kaolin, which indicated that kaolin can be used for natural scavenger of pollution in the environment.

  18. Stimulating nitrate removal processes of restored wetlands.

    Science.gov (United States)

    Ballantine, Kate A; Groffman, Peter M; Lehmann, Johannes; Schneider, Rebecca L

    2014-07-01

    The environmental and health effects caused by nitrate contamination of aquatic systems are a serious problem throughout the world. A strategy proposed to address nitrate pollution is the restoration of wetlands. However, although natural wetlands often remove nitrate via high rates of denitrification, wetlands restored for water quality functions often fall below expectations. This may be in part because key drivers for denitrification, in particular soil carbon, are slow to develop in restored wetlands. We added organic soil amendments that range along a gradient of carbon lability to four newly restored wetlands in western New York to investigate the effect of carbon additions on denitrification and other processes of the nitrogen cycle. Soil carbon increased by 12.67-63.30% with the use of soil amendments (p ≤ 0.0001). Soil nitrate, the carbon to nitrogen ratio, and microbial biomass nitrogen were the most significant predictors of denitrification potential. Denitrification potential, potential net nitrogen nitrification and mineralization, and soil nitrate and ammonium, were highest in topsoil-amended plots, with increases in denitrification potential of 161.27% over control plots. While amendment with topsoil more than doubled several key nitrogen cycling processes, more research is required to determine what type and level of amendment application are most effective for stimulating removal of exogenous nitrate and meeting functional goals within an acceptable time frame. PMID:24915604

  19. Sino-Danish Brain Circulation

    DEFF Research Database (Denmark)

    Bertelsen, Rasmus Gjedssø; Du, Xiangyun; Søndergaard, Morten Karnøe

    2014-01-01

    China is faced with urgent needs to develop an economically and environmentally sustainable economy based on innovation and knowledge. Brain circulation and research and business investments from the outside are central for this development. Sino-American brain circulation and research...... and investment by overseas researchers and entrepreneurs are well described. In that case, the US is the center of global R&D and S&T. However, the brain circulation and research and investments between a small open Scandinavian economy, such as Denmark, and the huge developing economy of China are not well...... understood. In this case, Denmark is very highly developed, but a satellite in the global R&D and S&T system. With time and the growth of China as a R&D and S&T power house, both Denmark and China will benefit from brain circulation between them. Such brain circulation is likely to play a key role in flows...

  20. TROPICAL METEOROLOGY & Climate: Hadley Circulation

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Jian; Vecchi, Gabriel A.

    2015-01-30

    The Hadley circulation, a prominent circulation feature characterized by rising air near the Equator and sinking air in the subtropics, defines the position of dry subtropical areas and is a fundamental regulator of the earth’s energy and momentum budgets. The character of the Hadley circulation, and its related precipitation regimes, exhibits variation and change in response to both climate variability and radiative forcing changes. The strength and position of the Hadley circulation change from year to year paced by El Niño and La Niña events. Over the last few decades of the twentieth century, the Hadley cell has expanded poleward in both hemispheres, with changes in atmospheric composition (including stratospheric ozone depletion and greenhouse gas increases) thought to have contributed to its expansion. This article introduces the basic phenomenology and driving mechanism of the Hadley circulation and discusses its variations under both natural and anthropogenic climate forcings.

  1. A regional survey on nitrate contamination of the Po valley alluvial aquifer (Northern Italy)

    International Nuclear Information System (INIS)

    The origin, distribution and abatement of nitrate contamination in surface and groundwater are traced by hydrochemical and stable isotope analyses. The studied sector of the Po Valley is approximately 3,600 km2 wide, extending from the Alps to the Apennine along a N-S transect. The phreatic aquifer is fed by local infiltration and by streams and irrigation channels, while the Po river represents the major discharge axis. The main diffuse source of nitrates is from synthetic fertilisers, exceedingly used for crop raising. Peak concentrations are instead associated to local leakage from sewage network. The distribution of groundwater contamination is closely related to the hydraulic characteristics of the unsaturated zone, to agricultural input and irrigation practices. Denitrification is observed along major draining rivers and below rice fields. Results are interpreted in terms of aquifer vulnerability, groundwater circulation and land use. (author)

  2. A regional survey on nitrate contamination of the Po Valley Alluvial Aquifer (Northern Italy)

    International Nuclear Information System (INIS)

    The origin, distribution and abatement of nitrate contamination in surface and groundwater are traced by hydrochemical and stable isotope analyses. The studied sector of the Po Valley is approximately 3 600 km2 wide, extending from the Alps to the Apennine along a N-S transect. The phreatic aquifer is fed by local infiltration and by streams and irrigation channels, while the Po river represents the major discharge axis. The main diffuse source of nitrates is from synthetic fertilisers, exceedingly used for crop raising. Peak concentrations are instead associated to local leakage from the sewage network.The distribution of groundwater contamination is closely related to the hydraulic characteristics of the unsaturated zone, to agricultural input and irrigation practices. Denitrification is observed along major draining rivers and below rice fields. Results are interpreted in terms of aquifer vulnerability, groundwater circulation and land use. (author)

  3. Historical Tracking of Nitrate in Contrasting Vineyard Using Water Isotopes and Nitrate Depth Profiles

    Science.gov (United States)

    Sprenger, M.; Erhardt, M.; Riedel, M.; Weiler, M.

    2015-12-01

    The European Water Framework Directive (EWFD) aims to achieve a good chemical status for the groundwater bodies in Europe by the year 2015. Despite the effort to reduce the nitrate pollution from agriculture within the last two decades, there are still many groundwater aquifers that exceed nitrate concentrations above the EWFD threshold of 50 mg/l. Viticulture is seen as a major contributor of nitrate leaching and sowing of a green cover was shown to have a positive effect on lowering the nitrate loads in the upper 90 cm of the soil. However, the consequences for nitrate leaching into the subsoil were not yet tested. We analyzed the nitrate concentrations and pore water stable isotope composition to a depth of 380 cm in soil profiles under an old vineyard and a young vineyard with either soil tillage or permanent green cover in between the grapevines. The pore water stable isotopes were used to calibrate a soil physical model, which was then used to infer the age of the soil water at different depths. This way, we could relate elevated nitrate concentrations below an old vineyard to tillage processes that took place during the winter two years before the sampling. We further showed that the elevated nitrate concentration in the subsoil of a young vineyard can be related to the soil tillage prior to the planting of the new vineyard. If the soil is kept bare due to tillage, a nitrate concentration of 200 kg NO3--N/ha is found in 290 to 380 cm depth 2.5 years after the installation of the vineyard. The amount of nitrate leaching is considerably reduced due to a seeded green cover between the grapevines that takes up a high share of the mobilized nitrate reducing a potential contamination of the groundwater.

  4. Nitrate ammonification in mangrove soils: A hidden source of nitrite?

    OpenAIRE

    Balk, Melike; Anniet M Laverman; Keuskamp, Joost A.; Laanbroek, Hendrikus J.

    2015-01-01

    Nitrate reduction is considered to be a minor microbial pathway in the oxidation of mangrove-derived organic matter due to a limited supply of nitrate in mangrove soils. At a limited availability of this electron acceptor compared to the supply of degradable carbon, nitrate ammonification is thought to be the preferential pathway of nitrate reduction. Mangrove forest mutually differ in their productivity, which may lead to different available carbon to nitrate ratios in their soil. Hence, nit...

  5. Containerized Wetland Bioreactor Evaluated for Perchlorate and Nitrate Degradation

    Energy Technology Data Exchange (ETDEWEB)

    Dibley, V R; Krauter, P W

    2004-12-02

    The U.S. Department of Energy (DOE) and Lawrence Livermore Laboratory (LLNL) designed and constructed an innovative containerized wetlands (bioreactor) system that began operation in November 2000 to biologically degrade perchlorate and nitrate under relatively low-flow conditions at a remote location at Site 300 known as Building 854. Since initial start-up, the system has processed over 3,463,000 liters of ground water and treated over 38 grams of perchlorate and 148 kilograms of nitrate. Site 300 is operated by the University of California as a high-explosives and materials testing facility supporting nuclear weapons research. The 11-square mile site located in northern California was added to the NPL in 1990 primarily due to the presence of elevated concentrations of volatile organic compounds (VOCs) in ground water. At the urging of the regulatory agencies, perchlorate was looked for and detected in the ground water in 1999. VOCs, nitrate and perchlorate were released into the soil and ground water in the Building 854 area as the result of accidental leaks during stability testing of weapons or from waste discharge practices that are no longer permitted at Site 300. Design of the wetland bioreactors was based on earlier studies showing that indigenous chlorate-respiring bacteria could effectively degrade perchlorate into nontoxic concentrations of chlorate, chlorite, oxygen, and chloride. Studies also showed that the addition of organic carbon would enhance microbial denitrification. Early onsite testing showed acetic acid to be a more effective carbon source than dried leaf matter, dried algae, or milk replacement starter; a nutrient and carbon source used in a Department of Defense phytoremediation demonstration. No inocula were added to the system. Groundwater was allowed to circulate through the bioreactor for three weeks to acclimate the wetland plants and to build a biofilm from indigenous flora. Using solar energy, ground water is pumped into granular

  6. Nitrate in aquifers beneath agricultural systems

    Science.gov (United States)

    Burkart, M.R.; Stoner, J.D.; ,

    2007-01-01

    Research from several regions of the world provides spatially anecdotal evidence to hypothesize which hydrologic and agricultural factors contribute to groundwater vulnerability to nitrate contamination. Analysis of nationally consistent measurements from the U.S. Geological Survey's NAWQA program confirms these hypotheses for a substantial range of agricultural systems. Shallow unconfined aquifers are most susceptible to nitrate contamination associated with agricultural systems. Alluvial and other unconsolidated aquifers are the most vulnerable and also shallow carbonate aquifers that provide a substantial but smaller contamination risk. Where any of these aquifers are overlain by permeable soils the risk of contamination is larger. Irrigated systems can compound this vulnerability by increasing leaching facilitated by additional recharge and additional nutrient applications. The system of corn, soybean, and hogs produced significantly larger concentrations of groundwater nitrate than all other agricultural systems because this system imports the largest amount of N-fertilizer per unit production area. Mean nitrate under dairy, poultry, horticulture, and cattle and grains systems were similar. If trends in the relation between increased fertilizer use and groundwater nitrate in the United States are repeated in other regions of the world, Asia may experience increasing problems because of recent increases in fertilizer use. Groundwater monitoring in Western and Eastern Europe as well as Russia over the next decade may provide data to determine if the trend in increased nitrate contamination can be reversed. If the concentrated livestock trend in the United States is global, it may be accompanied by increasing nitrogen contamination in groundwater. Concentrated livestock provide both point sources in the confinement area and intense non-point sources as fields close to facilities are used for manure disposal. Regions where irrigated cropland is expanding, such as

  7. Nitration of naphthalene and remarks on the mechanism of electrophilic aromatic nitration*

    Science.gov (United States)

    Olah, George A.; Narang, Subhash C.; Olah, Judith A.

    1981-01-01

    Naphthalene was nitrated with a variety of nitrating agents. Comparison of data with Perrin's electrochemical nitration [Perrin, C. L. (1977) J. Am. Chem. Soc. 99, 5516-5518] shows that nitration of naphthalene gives an α-nitronaphthalene to β-nitronaphthalene ratio that varies between 9 and 29 and is thus not constant. Perrin's data, therefore, are considered to be inconclusive evidence for the proposed one-electron transfer mechanism for the nitration of naphthalene and other reactive aromatics. Moodie and Schoefield [Hoggett, J. G., Moodie, R. B., Penton, J. R. & Schoefield, K. (1971) Nitration and Aromatic Reactivity (Cambridge Univ. Press, London)], as well as Perrin, independently concluded that, in the general scheme of nitration of reactive aromatics, there is the necessity to introduce into the classical Ingold mechanism an additional step involving a distinct intermediate preceding the formation of the Wheland intermediate (σ complexes). This view coincides with our two-step mechanistic picture [Kuhn, S. J. & Olah, G. A. (1961) J. Am. Chem. Soc. 83, 4564-4571] of the nitronium salt nitration of aromatic hydrocarbons (including benzene and toluene), in which low substrate selectivity but high positional selectivity was found, indicating the independence of substrate from positional selectivity. PMID:16593026

  8. Nitration of naphthalene and remarks on the mechanism of electrophilic aromatic nitration.

    Science.gov (United States)

    Olah, G A; Narang, S C; Olah, J A

    1981-06-01

    Naphthalene was nitrated with a variety of nitrating agents. Comparison of data with Perrin's electrochemical nitration [Perrin, C. L. (1977) J. Am. Chem. Soc. 99, 5516-5518] shows that nitration of naphthalene gives an alpha-nitronaphthalene to beta-nitronaphthalene ratio that varies between 9 and 29 and is thus not constant. Perrin's data, therefore, are considered to be inconclusive evidence for the proposed one-electron transfer mechanism for the nitration of naphthalene and other reactive aromatics. Moodie and Schoefield [Hoggett, J. G., Moodie, R. B., Penton, J. R. & Schoefield, K. (1971) Nitration and Aromatic Reactivity (Cambridge Univ. Press, London)], as well as Perrin, independently concluded that, in the general scheme of nitration of reactive aromatics, there is the necessity to introduce into the classical Ingold mechanism an additional step involving a distinct intermediate preceding the formation of the Wheland intermediate (sigma complexes). This view coincides with our two-step mechanistic picture [Kuhn, S. J. & Olah, G. A. (1961) J. Am. Chem. Soc. 83, 4564-4571] of the nitronium salt nitration of aromatic hydrocarbons (including benzene and toluene), in which low substrate selectivity but high positional selectivity was found, indicating the independence of substrate from positional selectivity. PMID:16593026

  9. Imbalance between vertical nitrate flux and nitrate assimilation on a continental shelf: Implications of nitrification

    Science.gov (United States)

    Shiozaki, Takuhei; Furuya, Ken; Kurotori, Hiroyuki; Kodama, Taketoshi; Takeda, Shigenobu; Endoh, Takahiro; Yoshikawa, Yutaka; Ishizaka, Joji; Matsuno, Takeshi

    2011-10-01

    The nitrate assimilation rate and diapycnal nitrate flux were simultaneously determined on the continental shelf of the East China Sea (ECS). Further, the archaeal amoA gene was quantified to examine the potential distribution of nitrification activity. Nitrate assimilation rates and distribution of the archaeal amoA gene were also investigated in the Philippine Sea and in the Kuroshio Current. At all the stations, while the surface nitrate was depleted (amoA was observed at shallower light depths, namely at or above 10% light depth, in the ECS than in other regions, suggesting that nitrification occurred within the euphotic zone in the ECS, especially on the shelf. Moreover, a station on the continental shelf of the ECS exhibited a considerable discrepancy between the nitrate assimilation rate (1500 μmolN m-2 d-1) and vertical nitrate flux (98 μmolN m-2 d-1). Here, 6.7 ± 3.1 × 103 and 2.5 ± 0.7 × 105 copies mL-1 of archaeal amoA were detected at 10% and 1% light depths relative to the surface, respectively. Thus nitrification within the euphotic zone would be attributed at least in part to the observed discrepancy between nitrate assimilation and vertical flux. These observations imply that the assumption of a direct relationship between new production, export production, and measured nitrate assimilation is misplaced, particularly regarding the continental shelf of the ECS.

  10. In situ analysis of microbial reduction of a nitrate plume in Opalinus clay

    International Nuclear Information System (INIS)

    Document available in extended abstract form only. In several countries, such as Belgium, France and Switzerland, clay formations are foreseen as the host rock for geological disposal of bituminized low-level and intermediate-level long-lived radioactive waste. Suitable clay formations exhibit favorable hydro-mechanical and geochemical characteristics, which are expected to retard the migration of leached radionuclides. Along with radionuclides, certain classes of bituminized radioactive waste may also contain high concentrations of NaNO3, dispersed into the hydrophobic bitumen matrix used to stabilize the waste. During and after saturation of the disposal gallery, this bituminized waste will start to take up water due to osmosis, resulting in the leaching of significant amounts of NaNO3 and soluble organic bitumen degradation products (BDP) into the clay pore water. This nitrate plume could cause several geochemical and biochemical processes in the clay surrounding the waste disposal gallery, potentially affecting the barrier function of the host rock. To study these processes, an in situ experiment in the Opalinus Clay, named the Bitumen-Nitrate-Clay interaction (BN) experiment, is being performed at the Mont Terri Rock Laboratory (CH). The experiment consists of a vertical borehole rigged with a downhole equipment containing three packed-off intervals, each lined with a cylindrical sintered stainless steel filter screen to allow contact with the surrounding clay. Prior to the start of the tests, the intervals were injected with an artificial Opalinus Clay pore water, containing all major ions at pore water concentrations at Mont Terri, but no organic matter, and were equilibrated with the surrounding clay for ∼8 months. To ensure a continuous water flow during the tests, each interval is connected to a stainless steel water circulation unit, equipped with water sampling containers, circulation pumps and flow meters. In addition, to continuously monitor the

  11. Ion Pairing in Alkali Nitrate Electrolyte Solutions.

    Science.gov (United States)

    Xie, Wen Jun; Zhang, Zhen; Gao, Yi Qin

    2016-03-10

    In this study, we investigate the thermodynamics of alkali nitrate salt solutions, especially the formation of contact ion pairs between alkali cation and nitrate anion. The ion-pairing propensity shows an order of LiNO3 law of matching water affinity" is followed by these alkali nitrate salt solutions. The spatial patterns of contact ion pairs are different in the three salt solutions studied here: Li(+) forms the contact ion pair with only one oxygen of the nitrate while Na(+) and K(+) can also be shared by two oxygens of the nitrate. In reproducing the salt activity coefficient using Kirkwood-Buff theory, we find that it is essential to include electronic polarization for Li(+) which has a high charge density. The electronic continuum correction for nonpolarizable force field significantly improves the agreement between the calculated activity coefficients and their experimental values. This approach also improves the performance of the force field on salt solubility. From these two aspects, this study suggests that electronic continuum correction can be a promising approach to force-field development for ions with high charge densities. PMID:26901167

  12. Ion Pairing in Alkali Nitrate Electrolyte Solutions.

    Science.gov (United States)

    Xie, Wen Jun; Zhang, Zhen; Gao, Yi Qin

    2016-03-10

    In this study, we investigate the thermodynamics of alkali nitrate salt solutions, especially the formation of contact ion pairs between alkali cation and nitrate anion. The ion-pairing propensity shows an order of LiNO3 activity coefficients and suggest that the empirical "law of matching water affinity" is followed by these alkali nitrate salt solutions. The spatial patterns of contact ion pairs are different in the three salt solutions studied here: Li(+) forms the contact ion pair with only one oxygen of the nitrate while Na(+) and K(+) can also be shared by two oxygens of the nitrate. In reproducing the salt activity coefficient using Kirkwood-Buff theory, we find that it is essential to include electronic polarization for Li(+) which has a high charge density. The electronic continuum correction for nonpolarizable force field significantly improves the agreement between the calculated activity coefficients and their experimental values. This approach also improves the performance of the force field on salt solubility. From these two aspects, this study suggests that electronic continuum correction can be a promising approach to force-field development for ions with high charge densities.

  13. Microbial Reduction of Chromate in the presence of Nitrate by Three Nitrate Respiring Organisms.

    Directory of Open Access Journals (Sweden)

    Peter eChovanec

    2012-12-01

    Full Text Available A major challenge for the bioremediation of toxic metals is the co-occurrence of nitrate, as it can inhibit metal transformation. Geobacter metallireducens, Desulfovibrio desulfuricans, and Sulfurospirillum barnesii are three soil bacteria that can reduce chromate (Cr(VI and nitrate, and may be beneficial for developing bioremediation strategies. All three organisms respire through dissimilatory nitrate reduction to ammonia (DNRA, employing different nitrate reductases but similar nitrite reductase (Nrf. G. metallireducens reduces nitrate to nitrite via the membrane bound nitrate reductase (Nar, while S. barnesii and D. desulfuricans strain 27774 have slightly different forms of periplasmic nitrate reductase (Nap. We investigated the effect of DNRA growth in the presence of Cr(VI in these three organisms and the ability of each to reduce Cr(VI to Cr(III, and each organisms responded differently. Growth of G. metallireducens on nitrate was completely inhibited by Cr(VI. Cultures of D. desulfuricans on nitrate media was initially delayed (48 h in the presence of Cr(VI, but ultimately reached comparable cell yields to the non-treated control. This prolonged lag phase accompanied the transformation of Cr(VI to Cr(III. Viable G. metallireducens cells could reduce Cr(VI, whereas Cr(VI reduction by D. desulfuricans during growth, was mediated by a filterable and heat stable extracellular metabolite. S. barnesii growth on nitrate was not affected by Cr(VI, and Cr(VI was reduced to Cr(III. However, Cr(VI reduction activity in S. barnesii, was detected in both the cell free spent medium and cells, indicating both extracellular and cell associated mechanisms. Taken together, these results have demonstrated that Cr(VI affects DNRA in the three organisms differently, and that each have a unique mechanism for Cr(VI reduction.

  14. The influence of Glyceria maxima and nitrate input on the composition and nitrate metabolism of the dissimilatory nitrate-reducing bacterial community

    NARCIS (Netherlands)

    Nijburg, J.W.; Laanbroek, H.J.

    1997-01-01

    The influence of nitrate addition and the presence of Glyceria maxima (reed sweetgrass) on the composition and nitrate metabolism of the dissimilatory nitrate-reducing bacterial community was investigated. Anoxic freshwater sediment was incubated in pots with or without G. maxima and with or without

  15. The circulation physiology of agroecosystems

    Institute of Scientific and Technical Information of China (English)

    Cao Zhiping; Richard Dawson

    2007-01-01

    This paper represents an effort to enlarge the understanding of the biophysical foundation of agroecosystems by using an analogy with the circulation of the blood in the human body. The circulation function in the human body can be represented as arterial pressure. The factors affecting arterial pressure in the human body have direct counterparts in the cultivation-husbandry system. The relationship between circulation pressure and the factors affecting that pressure in the cultivation-husbandry system are similar to the relationship between the arterial pressure and factors affecting arterial pressure in the human body. Furthermore, circulation resistance in the cultivation-husbandry system can be shown to be analogous to the calculation of peripheral resistance in the human body by Poiseuille's formula.

  16. Atmospheric Circulation of Terrestrial Exoplanets

    OpenAIRE

    Showman, Adam P.; Wordsworth, Robin D.; Merlis, Timothy M.; Kaspi, Yohai

    2013-01-01

    The investigation of planets around other stars began with the study of gas giants, but is now extending to the discovery and characterization of super-Earths and terrestrial planets. Motivated by this observational tide, we survey the basic dynamical principles governing the atmospheric circulation of terrestrial exoplanets, and discuss the interaction of their circulation with the hydrological cycle and global-scale climate feedbacks. Terrestrial exoplanets occupy a wide range of physical a...

  17. Trend Analyses of Nitrate in Danish Groundwater

    DEFF Research Database (Denmark)

    Hansen, B.; Thorling, L.; Dalgaard, Tommy;

    2012-01-01

    This presentation assesses the long-term development in the oxic groundwater nitrate concentration and nitrogen (N) loss due to intensive farming in Denmark. Firstly, up to 20-year time-series from the national groundwater monitoring network enable a statistically systematic analysis...... two dataset. The development in the nitrate concentration of oxic groundwater clearly mirrors the development in the national agricultural N surplus, and a corresponding trend reversal is found in groundwater. Regulation and technical improvements in the intensive farming in Denmark have succeeded...... in decreasing the N surplus by 40% since the mid 1980s while at the same time maintaining crop yields and increasing the animal production of especially pigs. Trend analyses prove that the youngest (0-15 years old) oxic groundwater shows more pronounced significant downward nitrate trends (44%) than the oldest...

  18. Nitrate isotope fractionations during biological nitrate reduction: Insights from first principles theoretical modeling

    Science.gov (United States)

    Guo, W.; Granger, J.; Sigman, D. M.

    2010-12-01

    Coupled fractionations of N and O isotopes during biological nitrate reduction provide important constraints on the marine nitrogen cycle at present and in the geologic past. Recent laboratory experiments with mono-cultures of nitrate-assimilative algae and plankton, and denitrifying bacteria demonstrate that N and O isotopic compositions of the residual nitrate co-vary linearly with a constant ratio (i.e., Δδ18O: Δδ15N) of ~1 or ~0.6 [1]. These systematic variations have been inferred to derive from the kinetic isotope fractionations associated with nitrate reductases. The isotope fractionation mechanisms at the enzymatic level, however, remain elusive. Here we present models of isotope fractionations accompanying the nitrate reduction (NO3-→NO2-) by three functional types of nitrate reductases, using techniques from ab initio, transition state and statistical thermodynamic theory. We consider three types of nitrate reductases: eukNR (eukaryotic assimilatory nitrate reductase), NAR (prokaryotic respiratory nitrate reductase) and Nap (prokaryotic periplasmic nitrate reductase). All are penta- or hexa-coordinated molybdo-enzymes, but bear considerable differences in protein geometry among functional types. Our models, based on the simplified structures of their active sites, predict N and O isotope effects (15ɛ and 18ɛ) ranging from 32.7 to 36.6‰ and from 33.5 to 34.8‰, respectively, at 300K with 18ɛ:15ɛ ratios of 0.9-1.1. The predicted amplitudes of N and O isotope fractionations are in the range measured for eukNR in vitro (~27‰, Karsh et al. in prep), and also correspond to the upper amplitudes observed for denitrifiers in vivo (~25‰, [1]). Moreover, the computed 18ɛ:15ɛ ratios corroborate the consistent relationships of ~1 observed experimentally for eukNR and the respiratory NAR. These findings indicate the enzymatic reduction is likely the rate-limiting step in most biological nitrate reductions. In addition, the predicted similarity of 18

  19. Efficient syntheses of climate relevant isoprene nitrates and (1R,5S)-(−)-myrtenol nitrate

    Science.gov (United States)

    Hiatt-Gipson, Glyn D; Mills, Graham P; Reeves, Claire E

    2016-01-01

    Summary Here we report the chemoselective synthesis of several important, climate relevant isoprene nitrates using silver nitrate to mediate a ’halide for nitrate’ substitution. Employing readily available starting materials, reagents and Horner–Wadsworth–Emmons chemistry the synthesis of easily separable, synthetically versatile ‘key building blocks’ (E)- and (Z)-3-methyl-4-chlorobut-2-en-1-ol as well as (E)- and (Z)-1-((2-methyl-4-bromobut-2-enyloxy)methyl)-4-methoxybenzene has been achieved using cheap, ’off the shelf’ materials. Exploiting their reactivity we have studied their ability to undergo an ‘allylic halide for allylic nitrate’ substitution reaction which we demonstrate generates (E)- and (Z)-3-methyl-4-hydroxybut-2-enyl nitrate, and (E)- and (Z)-2-methyl-4-hydroxybut-2-enyl nitrates (‘isoprene nitrates’) in 66–80% overall yields. Using NOESY experiments the elucidation of the carbon–carbon double bond configuration within the purified isoprene nitrates has been established. Further exemplifying our ‘halide for nitrate’ substitution chemistry we outline the straightforward transformation of (1R,2S)-(−)-myrtenol bromide into the previously unknown monoterpene nitrate (1R,2S)-(−)-myrtenol nitrate. PMID:27340495

  20. Determination of the total nitrate content of thorium nitrate solution with a selective electrode

    International Nuclear Information System (INIS)

    The nitrate content of thorium nitrate solutions is determined with a liquid membrane nitrate selective electrode utilizing the known addition method in 0.1 M potassium fluoride medium as ionic strength adjustor. It is studied the influence of pH and the presence of chloride, sulphate, phosphate, meta-silicate, thorium, rare earths, iron, titanium, uranium and zirconium at the same concentrations as for the aqueous feed solutions in the thorium purification process. The method is tested in synthetic samples and in samples proceeding from nitric dissolutions of thorium hidroxide and thorium oxicarbonate utilized as thorium concentrates to be purified

  1. Impact of Sulfide on Nitrate Conversion in Eutrophic Nitrate-Rich Marine Sludge

    DEFF Research Database (Denmark)

    Schwermer, Carsten U.; Krieger, Bärbel; Lavik, Gaute;

    2006-01-01

    IMPACT OF SULFIDE ON NITRATE CONVERSION IN EUTROPHIC NITRATE-RICH MARINE SLUDGE C.U. Schwermer 1, B.U. Krieger 2, G. Lavik 1, A. Schramm 3, J. van Rijn 4, D. de Beer 1, D. Minz 5, E. Cytryn 4, M. Kuypers 1, A. Gieseke 1 1 Max Planck Institute for Marine Microbiology, Bremen, Germany; 2 Dept...... and Environmental Sciences, Volcani Research Center, Bet-Dagan, Israel Multiple anaerobic processes are responsible for carbon mineralization in eutrophic nitrate-rich marine environments (e.g., upwelling areas, estuaries, and aquacultures), involving electron acceptors from both the nitrogen and sulfur cycle...

  2. Effect of betaine supplementation on plasma nitrate/nitrite in exercise-trained men

    Directory of Open Access Journals (Sweden)

    McCarthy Cameron G

    2011-03-01

    Full Text Available Abstract Background Betaine, beetroot juice, and supplemental nitrate have recently been reported to improve certain aspects of exercise performance, which may be mechanistically linked to increased nitric oxide. The purpose of the present study was to investigate the effect of betaine supplementation on plasma nitrate/nitrite, a surrogate marker or nitric oxide, in exercise-trained men. Methods We used three different study designs (acute intake of betaine at 1.25 and 5.00 grams, chronic intake of betaine at 2.5 grams per day for 14 days, and chronic [6 grams of betaine per day for 7 days] followed by acute intake [6 grams], all involving exercise-trained men, to investigate the effects of orally ingested betaine on plasma nitrate/nitrite. Blood samples were collected before and at 30, 60, 90, and 120 min after ingestion of 1.25 and 5.00 grams of betaine (Study 1; before and after 14 days of betaine supplementation at a dosage of 2.5 grams (Study 2; and before and after 7 days of betaine supplementation at a dosage of 6 grams, followed by acute ingestion of 6 grams and blood measures at 30 and 60 min post ingestion (Study 3. Results In Study 1, nitrate/nitrite was relatively unaffected and no statistically significant interaction (p = 0.99, dosage (p = 0.69, or time (p = 0.91 effects were noted. Similar findings were noted in Study 2, with no statistically significant interaction (p = 0.57, condition (p = 0.98, or pre/post intervention (p = 0.17 effects noted for nitrate/nitrite. In Study 3, no statistically significant changes were noted in nitrate/nitrite between collection times (p = 0.97. Conclusion Our data indicate that acute or chronic ingestion of betaine by healthy, exercise-trained men does not impact plasma nitrate/nitrite. These findings suggest that other mechanisms aside from increasing circulating nitric oxide are likely responsible for any performance enhancing effect of betaine supplementation.

  3. Seasonal overturning circulation in the Red Sea: 2. Winter circulation

    KAUST Repository

    Yao, Fengchao

    2014-04-01

    The shallow winter overturning circulation in the Red Sea is studied using a 50 year high-resolution MITgcm (MIT general circulation model) simulation with realistic atmospheric forcing. The overturning circulation for a typical year, represented by 1980, and the climatological mean are analyzed using model output to delineate the three-dimensional structure and to investigate the underlying dynamical mechanisms. The horizontal model circulation in the winter of 1980 is dominated by energetic eddies. The climatological model mean results suggest that the surface inflow intensifies in a western boundary current in the southern Red Sea that switches to an eastern boundary current north of 24N. The overturning is accomplished through a cyclonic recirculation and a cross-basin overturning circulation in the northern Red Sea, with major sinking occurring along a narrow band of width about 20 km along the eastern boundary and weaker upwelling along the western boundary. The northward pressure gradient force, strong vertical mixing, and horizontal mixing near the boundary are the essential dynamical components in the model\\'s winter overturning circulation. The simulated water exchange is not hydraulically controlled in the Strait of Bab el Mandeb; instead, the exchange is limited by bottom and lateral boundary friction and, to a lesser extent, by interfacial friction due to the vertical viscosity at the interface between the inflow and the outflow. Key Points Sinking occurs in a narrow boundary layer along the eastern boundary Surface western boundary current switches into an eastern boundary current Water exchange in the Strait of Bab el Mandeb is not hydraulically controlled © 2014. American Geophysical Union. All Rights Reserved.

  4. Denitration of High Nitrate Salts Using Reductants

    Energy Technology Data Exchange (ETDEWEB)

    HD Smith; EO Jones; AJ Schmidt; AH Zacher; MD Brown; MR Elmore; SR Gano

    1999-05-03

    This report describes work conducted by Pacific Northwest National Laboratory (PNNL), in conjunction with Idaho National Engineering and Environmental Laboratory (INEEL), to remove nitrates in simulated low-activity waste (LAW). The major objective of this work was to provide data for identifying and demonstrating a technically viable and cost-effective approach to condition LAW for immobilization (grout).

  5. Reinforced Sisal Fiber with Ferric Nitrate Composites

    Directory of Open Access Journals (Sweden)

    Asif Jehan

    2015-06-01

    Full Text Available Ferric oxide synthesized through annealing route. The present research work deals with ferrite composite prepared using chemical reactions. Ferric nitrates and ammonium chloride doped with sisal fiber has been prepared. The structural behavior of aluminum oxide was studied in XRD, SEM, TEM, FTIR & dielectric measurement. This behavior showed ferrite nature of the sample.

  6. 76 FR 47238 - Ammonium Nitrate From Russia

    Science.gov (United States)

    2011-08-04

    ...)). Background The Commission instituted this review on March 1, 2011 (76 FR 11273) and determined on June 6, 2011 that it would conduct an expedited review (76 FR 34749, June 14, 2011). The Commission transmitted... COMMISSION Ammonium Nitrate From Russia Determination On the basis of the record \\1\\ developed in the...

  7. 76 FR 11273 - Ammonium Nitrate From Russia

    Science.gov (United States)

    2011-03-01

    ... nitrate from Russia (71 FR 17080). The Commission is now conducting a second review to determine whether... recently amended at 74 FR 2847 (January 16, 2009). \\1\\ No response to this request for information is... (65 FR 37759, June 16, 2000). Following five-year reviews by Commerce and the Commission,...

  8. Enzyme catalytic nitration of aromatic compounds.

    Science.gov (United States)

    Kong, Mingming; Wang, Kun; Dong, Runan; Gao, Haijun

    2015-06-01

    Nitroaromatic compounds are important intermediates in organic synthesis. The classic method used to synthesize them is chemical nitration, which involves the use of nitric acid diluted in water or acetic acid, both harmful to the environment. With the development of green chemistry, environmental friendly enzyme catalysis is increasingly employed in chemical processes. In this work, we adopted a non-aqueous horseradish peroxidase (HRP)/NaNO2/H2O2 reaction system to study the structural characteristics of aromatic compounds potentially nitrated by enzyme catalysis, as well as the relationship between the charges on carbon atoms in benzene ring and the nitro product distribution. Investigation of various reaction parameters showed that mild reaction conditions (ambient temperature and neutral pH), plus appropriate use of H2O2 and NaNO2 could prevent inactivation of HRP and polymerization of the substrates. Compared to aqueous-organic co-solvent reaction media, the aqueous-organic two-liquid phase system had great advantages in increasing the dissolved concentration of substrate and alleviating substrate inhibition. Analysis of the aromatic compounds' structural characteristics indicated that substrates containing substituents of NH2 or OH were readily catalyzed. Furthermore, analysis of the relationship between natural bond orbital (NBO) charges on carbon atoms in benzene ring, as calculated by the density functional method, and the nitro product distribution characteristics, demonstrated that the favored nitration sites were the ortho and para positions of substituents in benzene ring, similar to the selectivity of chemical nitration.

  9. Background-like nitrate in desert air

    Science.gov (United States)

    Wu, Feng; Zhang, Daizhou; Cao, Junji; Zhang, Ting; An, Zhisheng

    2014-02-01

    The atmospheric nitrogen cycle is a key process driving the earth's environmental evolution. Current model studies require knowledge of NOx soil emissions from various land types, but desert emissions remain unquantified or are not addressed with high confidence. Our measurements at two observatories in Taklimakan desert during a dust episode showed an approximately stable and dust-independent nitrate in the air. Its concentration estimated from PM2.5, PM10 and TSP samples under non-dust, floating dust and dust storm conditions was 3.81 ± 1.24 μg m-3, 2.95 ± 0.69 μg m-3, 4.99 ± 1.71 μg m-3, respectively, despite the more-than-one-order difference of dust loading. This concentration was much larger than that in remote marine and tropical forest air. Comprehensive investigation revealed a similar presence of nitrate in other desert air. The nitrate was hypothesized to be the consequence of the conversion of NOx released from desert soils. These results indicate a background-like nitrate and active reactions of nitrogen compounds in desert air.

  10. Detonation characteristics of ammonium nitrate products

    NARCIS (Netherlands)

    Kersten, R.J.A.; Hengel, E.I.V. van den; Steen, A.C. van der

    2006-01-01

    The detonation properties of ammonium nitrate (AN) products depend on many factors and are therefore, despite the large amount of information on this topic, difficult to assess. In order to further improve the understanding of the safety properties of AN, the European Fertilizer Manufacturers Associ

  11. The Path to Nitrate Salt Disposition

    Energy Technology Data Exchange (ETDEWEB)

    Funk, David John [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-03-16

    The topic is presented in a series of slides arranged according to the following outline: LANL nitrate salt incident as thermal runaway (thermally sensitive surrogates, full-scale tests), temperature control for processing, treatment options and down selection, assessment of engineering options, anticipated control set for treatment, and summary of the overall steps for RNS.

  12. 76 FR 46907 - Ammonium Nitrate Security Program

    Science.gov (United States)

    2011-08-03

    ... comments. SUMMARY: This proposed rule would implement anti-terrorism measures to better secure the homeland... purpose of preventing the use of ammonium nitrate in an act of terrorism. This proposed rule seeks comment... Administration POC Point of Contact QATT Qualified Anti-Terrorism Technology RFA Regulatory Flexibility...

  13. Nitrate Salt Surrogate Blending Scoping Test Plan

    Energy Technology Data Exchange (ETDEWEB)

    Anast, Kurt Roy [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-11-13

    Test blending equipment identified in the “Engineering Options Assessment Report: Nitrate Salt Waste Stream Processing”. Determine if the equipment will provide adequate mixing of zeolite and surrogate salt/Swheat stream; optimize equipment type and operational sequencing; impact of baffles and inserts on mixing performance; and means of validating mixing performance

  14. Nitrates, Nitrites, and Health. Bulletin 750.

    Science.gov (United States)

    Deeb, Barbara S.; Sloan, Kenneth W.

    This review is intended to assess available literature in order to define the range of nitrate/nitrite effects on animals. Though the literature deals primarily with livestock and experimental animals, much of the contemporary research is concerned with human nitrite intoxication. Thus, the effects on man are discussed where appropriate. Some of…

  15. The Invertibility, Explicit Determinants, and Inverses of Circulant and Left Circulant and g-Circulant Matrices Involving Any Continuous Fibonacci and Lucas Numbers

    Directory of Open Access Journals (Sweden)

    Zhaolin Jiang

    2014-01-01

    Full Text Available Circulant matrices play an important role in solving delay differential equations. In this paper, circulant type matrices including the circulant and left circulant and g-circulant matrices with any continuous Fibonacci and Lucas numbers are considered. Firstly, the invertibility of the circulant matrix is discussed and the explicit determinant and the inverse matrices by constructing the transformation matrices are presented. Furthermore, the invertibility of the left circulant and g-circulant matrices is also studied. We obtain the explicit determinants and the inverse matrices of the left circulant and g-circulant matrices by utilizing the relationship between left circulant, g-circulant matrices and circulant matrix, respectively.

  16. Gastric S-nitrosothiol formation drives the antihypertensive effects of oral sodium nitrite and nitrate in a rat model of renovascular hypertension.

    Science.gov (United States)

    Pinheiro, Lucas C; Amaral, Jefferson H; Ferreira, Graziele C; Portella, Rafael L; Ceron, Carla S; Montenegro, Marcelo F; Toledo, Jose Carlos; Tanus-Santos, Jose E

    2015-10-01

    Many effects of nitrite and nitrate are attributed to increased circulating concentrations of nitrite, ultimately converted into nitric oxide (NO(•)) in the circulation or in tissues by mechanisms associated with nitrite reductase activity. However, nitrite generates NO(•) , nitrous anhydride, and other nitrosating species at low pH, and these reactions promote S-nitrosothiol formation when nitrites are in the stomach. We hypothesized that the antihypertensive effects of orally administered nitrite or nitrate involve the formation of S-nitrosothiols, and that those effects depend on gastric pH. The chronic effects of oral nitrite or nitrate were studied in two-kidney, one-clip (2K1C) hypertensive rats treated with omeprazole (or vehicle). Oral nitrite lowered blood pressure and increased plasma S-nitrosothiol concentrations independently of circulating nitrite levels. Increasing gastric pH with omeprazole did not affect the increases in plasma nitrite and nitrate levels found after treatment with nitrite. However, treatment with omeprazole severely attenuated the increases in plasma S-nitrosothiol concentrations and completely blunted the antihypertensive effects of nitrite. Confirming these findings, very similar results were found with oral nitrate. To further confirm the role of gastric S-nitrosothiol formation, we studied the effects of oral nitrite in hypertensive rats treated with the glutathione synthase inhibitor buthionine sulfoximine (BSO) to induce partial thiol depletion. BSO treatment attenuated the increases in S-nitrosothiol concentrations and antihypertensive effects of oral nitrite. These data show that gastric S-nitrosothiol formation drives the antihypertensive effects of oral nitrite or nitrate and has major implications, particularly to patients taking proton pump inhibitors. PMID:26159506

  17. NITRATE DESTRUCTION LITERATURE SURVEY AND EVALUATION CRITERIA

    Energy Technology Data Exchange (ETDEWEB)

    Steimke, J.

    2011-02-01

    This report satisfies the initial phase of Task WP-2.3.4 Alternative Sodium Recovery Technology, Subtask 1; Develop Near-Tank Nitrate/Nitrite Destruction Technology. Some of the more common anions in carbon steel waste tanks at SRS and Hanford Site are nitrate which is corrosive, and nitrite and hydroxide which are corrosion inhibitors. At present it is necessary to periodically add large quantities of 50 wt% caustic to waste tanks. There are three primary reasons for this addition. First, when the contents of salt tanks are dissolved, sodium hydroxide preferentially dissolves and is removed. During the dissolution process the concentration of free hydroxide in the tank liquid can decrease from 9 M to less than 0.2 M. As a result, roughly half way through the dissolution process large quantities of sodium hydroxide must be added to the tank to comply with requirements for corrosion control. Second, hydroxide is continuously consumed by reaction with carbon dioxide which occurs naturally in purge air used to prevent buildup of hydrogen gas inside the tanks. The hydrogen is generated by radiolysis of water. Third, increasing the concentration of hydroxide increases solubility of some aluminum compounds, which is desirable in processing waste. A process that converts nitrate and nitrite to hydroxide would reduce certain costs. (1) Less caustic would be purchased. (2) Some of the aluminum solid compounds in the waste tanks would become more soluble so less mass of solids would be sent to High Level Vitrification and therefore it would be not be necessary to make as much expensive high level vitrified product. (3) Less mass of sodium would be fed to Saltstone at SRS or Low Level Vitrification at Hanford Site so it would not be necessary to make as much low level product. (4) At SRS less nitrite and nitrate would be sent to Defense Waste Processing Facility (DWPF) so less formic acid would be consumed there and less hydrogen gas would be generated. This task involves

  18. Evidence for a plasma-membrane-bound nitrate reductase involved in nitrate uptake of Chlorella sorokiniana

    Science.gov (United States)

    Tischner, R.; Ward, M. R.; Huffaker, R. C.

    1989-01-01

    Anti-nitrate-reductase (NR) immunoglobulin-G (IgG) fragments inhibited nitrate uptake into Chlorella cells but had no affect on nitrate uptake. Intact anti-NR serum and preimmune IgG fragments had no affect on nitrate uptake. Membrane-associated NR was detected in plasma-membrane (PM) fractions isolated by aqueous two-phase partitioning. The PM-associated NR was not removed by sonicating PM vesicles in 500 mM NaCl and 1 mM ethylenediaminetetraacetic acid and represented up to 0.8% of the total Chlorella NR activity. The PM NR was solubilized by Triton X-100 and inactivated by Chlorella NR antiserum. Plasma-membrane NR was present in ammonium-grown Chlorella cells that completely lacked soluble NR activity. The subunit sizes of the PM and soluble NRs were 60 and 95 kDa, respectively, as determined by sodium-dodecyl-sulfate electrophoresis and western blotting.

  19. Heating efficiency of microwave heating direct denitration of a mixture of uranyl nitrate and plutonium nitrate

    International Nuclear Information System (INIS)

    A mixture of plutonium nitrate and uranyl nitrate is co-converted to MOX powder by the microwave heating method developed by JAEA. The heating efficiency is very important for improving the energy-saving performance in this conversion process. In this study, the heating efficiency was measured using both experimental and engineering-scale microwave ovens in water, nitric acid and a mixture of plutonium nitrate and uranyl nitrate as a function of distance between the specimen and the base of the oven. In addition, the distribution of electromagnetic field strength and its absorption concentration in the solution were numerically evaluated by an electromagnetic field analysis code, MWS 2009. The experimental results could almost be explained by the numerical analysis results. When the distance of the specimen and the base of the oven was beyond 1/4 wavelength, the efficiency became constant because the influence disappeared. (author)

  20. Electrochemical processing of nitrate waste solutions

    International Nuclear Information System (INIS)

    The second phase of research performed at The Electrosynthesis Co., Inc. has demonstrated the successful removal of nitrite and nitrate from a synthetic effluent stream via a direct electrochemical reduction at a cathode. It was shown that direct reduction occurs at good current efficiencies in 1,000 hour studies. The membrane separation process is not readily achievable for the removal of nitrites and nitrates due to poor current efficiencies and membrane stability problems. A direct reduction process was studied at various cathode materials in a flow cell using the complete synthetic mix. Lead was found to be the cathode material of choice, displaying good current efficiencies and stability in short and long term tests under conditions of high temperature and high current density. Several anode materials were studied in both undivided and divided cell configurations. A divided cell configuration was preferable because it would prevent re-oxidation of nitrite by the anode. The technical objective of eliminating electrode fouling and solids formation was achieved although anode materials which had demonstrated good stability in short term divided cell tests corroded in 1,000 hour experiments. The cause for corrosion is thought to be F- ions from the synthetic mix migrating across the cation exchange membrane and forming HF in the acid anolyte. Other possibilities for anode materials were explored. A membrane separation process was investigated which employs an anion and cation exchange membrane to remove nitrite and nitrate, recovering caustic and nitric acid. Present research has shown poor current efficiencies for nitrite and nitrate transport across the anion exchange membrane due to co-migration of hydroxide anions. Precipitates form within the anion exchange membranes which would eventually result in the failure of the membranes. Electrochemical processing offers a highly promising and viable method for the treatment of nitrate waste solutions

  1. Spatial assessment of animal manure spreading and groundwater nitrate pollution

    OpenAIRE

    Roberta Infascelli; Raffaele Pelorosso; Lorenzo Boccia

    2009-01-01

    Nitrate concentration in groundwater has frequently been linked to non-point pollution. At the same time the existence of intensive agriculture and extremely intensive livestock activity increases the potential for nitrate pollution in shallow groundwater. Nitrate used in agriculture could cause adverse effects on human and animal health. In order to evaluate the groundwater nitrate pollution, and how it might evolve in time, it is essential to develop control systems and to improve policies ...

  2. Nitrate mass balance in the Padež stream watershed

    OpenAIRE

    Česnik, Katarina

    2014-01-01

    Graduation thesis analyzes changes in nitrate mass balance in a forested watersheds. The nitrate mass balance changes occur manly because of hydrological and biogeochemical mechanisms. The studied area, the Padež stream watershed, is mainly covered with forest. Between years 2006 and 2007 the hydrometeorological conditions and streamwater chemistry of Padež stream were continuously monitored. The differences in streamwater nitrate concentrations and nitrate concentrations in precipitations an...

  3. Amperometric nitrate biosensor based on Carbon nanotube/Polypyrrole/Nitrate reductase biofilm electrode

    Energy Technology Data Exchange (ETDEWEB)

    Can, Faruk; Korkut Ozoner, Seyda; Ergenekon, Pinar; Erhan, Elif, E-mail: e.erhan@gyte.edu.tr

    2012-01-01

    This study describes the construction and characterization of an amperometric nitrate biosensor based on the Polypyrrole (PPy)/Carbon nanotubes (CNTs) film. Nitrate reductase (NR) was both entrapped into the growing PPy film and chemically immobilized via the carboxyl groups of CNTs to the CNT/PPy film electrode. The optimum amperometric response for nitrate was obtained in 0.1 M phosphate buffer solution (PBS), pH 7.5 including 0.1 M lithium chloride and 7 mM potassium ferricyanide with an applied potential of 0.13 V (vs. Ag/AgCl, 3 M NaCl). Sensitivity was found to be 300 nA/mM in a linear range of 0.44-1.45 mM with a regression coefficient of 0.97. The biosensor response showed a higher linear range in comparison to standard nitrate analysis methods which were tested in this study and NADH based nitrate biosensors. A minimum detectable concentration of 0.17 mM (S/N = 3) with a relative standard deviation (RSD) of 5.4% (n = 7) was obtained for the biosensor. Phenol and glucose inhibit the electrochemical reaction strictly at a concentration of 1 {mu}g/L and 20 mg/L, respectively. The biosensor response retained 70% of its initial response over 10 day usage period when used everyday. - Highlights: Black-Right-Pointing-Pointer K{sub 3}Fe(CN){sub 6} has been used for the first time as mediator for nitrate reductase. Black-Right-Pointing-Pointer Better performance was obtained in comparison to other nitrate biosensor studies operated with various mediators. Black-Right-Pointing-Pointer Analytical parameters were better than standard nitrate analysis methods.

  4. Amperometric nitrate biosensor based on Carbon nanotube/Polypyrrole/Nitrate reductase biofilm electrode

    International Nuclear Information System (INIS)

    This study describes the construction and characterization of an amperometric nitrate biosensor based on the Polypyrrole (PPy)/Carbon nanotubes (CNTs) film. Nitrate reductase (NR) was both entrapped into the growing PPy film and chemically immobilized via the carboxyl groups of CNTs to the CNT/PPy film electrode. The optimum amperometric response for nitrate was obtained in 0.1 M phosphate buffer solution (PBS), pH 7.5 including 0.1 M lithium chloride and 7 mM potassium ferricyanide with an applied potential of 0.13 V (vs. Ag/AgCl, 3 M NaCl). Sensitivity was found to be 300 nA/mM in a linear range of 0.44–1.45 mM with a regression coefficient of 0.97. The biosensor response showed a higher linear range in comparison to standard nitrate analysis methods which were tested in this study and NADH based nitrate biosensors. A minimum detectable concentration of 0.17 mM (S/N = 3) with a relative standard deviation (RSD) of 5.4% (n = 7) was obtained for the biosensor. Phenol and glucose inhibit the electrochemical reaction strictly at a concentration of 1 μg/L and 20 mg/L, respectively. The biosensor response retained 70% of its initial response over 10 day usage period when used everyday. - Highlights: ► K3Fe(CN)6 has been used for the first time as mediator for nitrate reductase. ► Better performance was obtained in comparison to other nitrate biosensor studies operated with various mediators. ► Analytical parameters were better than standard nitrate analysis methods.

  5. [Circulating nucleic acids and infertility].

    Science.gov (United States)

    Scalici, E; Mullet, T; Ferrières Hoa, A; Gala, A; Loup, V; Anahory, T; Belloc, S; Hamamah, S

    2015-09-01

    Circulating nucleic acids (cell-free DNA and microRNAs) have for particularity to be easily detectable in the biological fluids of the body. Therefore, they constitute biomarkers of interest in female and male infertility care. Indeed, in female, they can be used to detect ovarian reserve disorders (polycystic ovary syndrome and low functional ovarian reserve) as well as to assess follicular microenvironment quality. Moreover, in men, their expression levels can vary in case of spermatogenesis abnormalities. Finally, circulating nucleic acids have also the ability to predict successfully the quality of in vitro embryo development. Their multiple contributions during assisted reproductive technology (ART) make of them biomarkers of interest, for the development of new diagnostic and/or prognostic tests, applied to our specialty. Circulating nucleic acids would so offer the possibility of personalized medical care for infertile couples in ART. PMID:26298813

  6. Atmospheric Circulation of Terrestrial Exoplanets

    CERN Document Server

    Showman, Adam P; Merlis, Timothy M; Kaspi, Yohai

    2013-01-01

    The investigation of planets around other stars began with the study of gas giants, but is now extending to the discovery and characterization of super-Earths and terrestrial planets. Motivated by this observational tide, we survey the basic dynamical principles governing the atmospheric circulation of terrestrial exoplanets, and discuss the interaction of their circulation with the hydrological cycle and global-scale climate feedbacks. Terrestrial exoplanets occupy a wide range of physical and dynamical conditions, only a small fraction of which have yet been explored in detail. Our approach is to lay out the fundamental dynamical principles governing the atmospheric circulation on terrestrial planets--broadly defined--and show how they can provide a foundation for understanding the atmospheric behavior of these worlds. We first survey basic atmospheric dynamics, including the role of geostrophy, baroclinic instabilities, and jets in the strongly rotating regime (the "extratropics") and the role of the Hadle...

  7. Extraction of nitric acid, uranyl nitrate, and bismuth nitrate from aqueous nitric acid solutions with CMPO

    Energy Technology Data Exchange (ETDEWEB)

    Spencer, B.B.

    1995-08-01

    DOE sponsored development of the transuranium extraction (TRUEX) process for removing actinides from radioactive wastes. The solvent is a mixture of CMPO and TBP. Since the extraction characteristics of CMPO are not as well understood as those of TBP, the extraction of nitric acid, uranyl nitrate, and bismuth nitrate with CMPO (dissolved in n-dodecane) were studied. Results indicate that CMPO extracts nitric acid with a 1:1 stoichiometry; equilibrium constant is 2. 660{plus_minus}0.092 at 25 C, and extraction enthalpy is -5. 46{plus_minus}0.46 kcal/mol. Slope analysis indicates that uranyl nitrate extracts with a mixed equilibria of 1:1 and 2:1 stoichiometries in nearly equal proportion. Equil. constant of the 2: 1 extraction was 1.213 {times} 10{sup 6}{plus_minus}3.56 {times} 10{sup 4} at 25 C; reaction enthalpy was -9.610{plus_minus}0.594 kcal/mol. Nitration complexation constant is 8.412{plus_minus}0.579, with an enthalpy of -10.72{plus_minus}1.87 kcal/mol. Bismuth nitrate also extracts with a mixed equilibria of (perhaps) 1:1 and 2:1 stoichiometries. A 2:1 extraction equilibrium and a nitrate complexation adequately model the data. Kinetics and enthalpies were also measured.

  8. Extraction of nitric acid, uranyl nitrate, and bismuth nitrate from aqueous nitric acid solutions with CMPO

    International Nuclear Information System (INIS)

    DOE sponsored development of the transuranium extraction (TRUEX) process for removing actinides from radioactive wastes. The solvent is a mixture of CMPO and TBP. Since the extraction characteristics of CMPO are not as well understood as those of TBP, the extraction of nitric acid, uranyl nitrate, and bismuth nitrate with CMPO (dissolved in n-dodecane) were studied. Results indicate that CMPO extracts nitric acid with a 1:1 stoichiometry; equilibrium constant is 2. 660±0.092 at 25 C, and extraction enthalpy is -5. 46±0.46 kcal/mol. Slope analysis indicates that uranyl nitrate extracts with a mixed equilibria of 1:1 and 2:1 stoichiometries in nearly equal proportion. Equil. constant of the 2: 1 extraction was 1.213 x 106±3.56 x 104 at 25 C; reaction enthalpy was -9.610±0.594 kcal/mol. Nitration complexation constant is 8.412±0.579, with an enthalpy of -10.72±1.87 kcal/mol. Bismuth nitrate also extracts with a mixed equilibria of (perhaps) 1:1 and 2:1 stoichiometries. A 2:1 extraction equilibrium and a nitrate complexation adequately model the data. Kinetics and enthalpies were also measured

  9. Disposable nitrate-selective optical sensor based on fluorescent dye

    Science.gov (United States)

    A simple, disposable thin-film optical nitrate sensor was developed. The sensor was fabricated by applying a nitrate-selective polymer membrane on the surface of a thin polyester film. The membrane was composed of polyvinylchloride (PVC), plasticizer, fluorescent dye, and nitrate-selective ionophore...

  10. Nitrate ammonification in mangrove soils: A hidden source of nitrite?

    NARCIS (Netherlands)

    Balk, Melike; Laverman, A.M.; Keuskamp, Joost A.; Laanbroek, Hendrikus J.

    2015-01-01

    Nitrate reduction is considered to be a minor microbial pathway in the oxidation of mangrove-derived organic matter due to a limited supply of nitrate in mangrove soils. At a limited availability of this electron acceptor compared to the supply of degradable carbon, nitrate ammonification is thought

  11. 21 CFR 176.320 - Sodium nitrate-urea complex.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sodium nitrate-urea complex. 176.320 Section 176... Substances for Use Only as Components of Paper and Paperboard § 176.320 Sodium nitrate-urea complex. Sodium nitrate-urea complex may be safely used as a component of articles intended for use in...

  12. Nitrate to ammonia ceramic (NAC) bench scale stabilization study

    Energy Technology Data Exchange (ETDEWEB)

    Caime, W.J.; Hoeffner, S.L. [RUST - Clemson Technical Center, Anderson, SC (United States)

    1995-10-01

    Department of Energy (DOE) sites such as the Hanford site, Idaho National Engineering Laboratory (INEL), Savannah River site, Oak Ridge National Laboratory (ORNL) have large quantities of sodium-nitrate based liquid wastes. A process to reduce the nitrates to ammonia has been developed at ORNL. This technology creates a sludge lower in nitrates. This report describes stabilization possibilities of the sludge.

  13. 9 CFR 319.2 - Products and nitrates and nitrites.

    Science.gov (United States)

    2010-01-01

    ... standard in this part and to which nitrate or nitrite is permitted or required to be added, may be prepared without nitrate or nitrite and labeled with such standard name when immediately preceded with the term... to such product as commonly prepared with nitrate and nitrite: And provided further, That...

  14. Experimental and theoretical studies in Molten Salt Natural Circulation Loop (MSNCL)

    International Nuclear Information System (INIS)

    High Temperature Reactors (HTR) and solar thermal power plants use molten salt as a coolant, as it has low melting point and high boiling point, enabling us to operate the system at low pressure. Molten fluoride salt and molten nitrate salt are proposed as a candidate coolant for High Temperature Reactors (HTR) and solar power plant respectively. BARC is developing a 600 MWth pebble bed high temperature reactor, cooled by natural circulation of fluoride salt and capable of supplying process heat at 1000°C to facilitate hydrogen production by splitting water. Beside this, BARC is also developing a 2MWe solar power tower system using molten nitrate salt. With these requirements, a Molten Salt Natural Circulation Loop (MSNCL) has been designed, fabricated, installed and commissioned in Hall-7, BARC for thermal hydraulic, instrumentation development and material compatibility related studies. Steady state natural circulation experiments with molten nitrate salt (mixture of NaNO3 and KNO3 in 60:40 ratio) have been carried out in the loop at different power level. Various transients viz. startup of natural circulation, step power change, loss of heat sink and heater trip has also been studied in the loop. A well known steady state correlation given by Vijayan et. al. has been compared with experimental data. In-house developed code LeBENC has also been validated against all steady state and transient experimental results. The detailed description of MSNCL, steady state and transient experimental results and validation of in-house developed code LeBENC have been described in this report. (author)

  15. Proper Sizing of Circulation Pumps

    DEFF Research Database (Denmark)

    Tommerup, Henrik M.; Nørgaard, Jørgen

    2007-01-01

    , but the results can be applied to Europe in general. Despite the small sample of houses involved in the test, 15 houses, some rather safe conclusions can be drawn from the results, which showed that newly developed pumps with power consumption around 5-8 W, can perform the task of circulating the water...... as well as their pollution during operation. Policy measures are proposed of how to ensure that in the future only such energy saving pumps are installed. Furthermore, on the basis of the historic experiences with circulation pumps some con¬clusions are drawn on how to investigate, develop and market new...

  16. Laboratory study of nitrate photolysis in Antarctic snow

    DEFF Research Database (Denmark)

    Berhanu, Tesfaye A.; Meusinger, Carl; Erbland, Joseph;

    2014-01-01

    in Antarctic snow. I. Observed quantum yield, domain of photolysis, and secondary chemistry," J. Chem. Phys. 140, 244305 (2014)]) is to characterize nitrate photochemistry and improve the interpretation of the nitrate ice core record. Naturally occurring stable isotopes in nitrate (15N, 17O, and 18O) provide......Atmospheric nitrate is preserved in Antarctic snow firn and ice. However, at low snow accumulation sites, post-depositional processes induced by sunlight obscure its interpretation. The goal of these studies (see also Paper I by Meusinger et al. [" Laboratory study of nitrate photolysis...

  17. Catalytic hydrogenation of uranyl nitrate - engineering scale studies

    International Nuclear Information System (INIS)

    Uranous nitrate is employed as partitioning agent for the separation of plutonium from uranium in PUREX process, the conventional process for the reprocessing of spent nuclear fuel. It is currently produced from uranyl nitrate solution by the electrochemical route. Since the conversion is only 50%, an innovative method based on catalytic hydrogenation has been developed. Parametric studies have been carried out on 5 L scale using natural uranyl nitrate solution as fed. Based on these studies, number of runs were carried out on engineering scale using contaminated uranyl nitrate solution. More than 100 kg of uranous nitrate has been made. Performance of the reduction process is described in detail. (author)

  18. Conservation of Circulation in Magnetohydrodynamics

    CERN Document Server

    Bekenstein, J D; Bekenstein, Jacob D.; Oron, Asaf

    2000-01-01

    We demonstrate, both at the Newtonian and (general) relativistic levels, theexistence of a generalization of Kelvin's circulation theorem (for pure fluids)which is applicable to perfect magnetohydrodynamics. The argument is based onthe least action principle for magnetohydrodynamic flow. Examples of the newconservation law are furnished. The new theorem should be helpful inidentifying new kinds of vortex phenomena distinct from magnetic ropes or fluidvortices.

  19. Neural Control of the Circulation

    Science.gov (United States)

    Thomas, Gail D.

    2011-01-01

    The purpose of this brief review is to highlight key concepts about the neural control of the circulation that graduate and medical students should be expected to incorporate into their general knowledge of human physiology. The focus is largely on the sympathetic nerves, which have a dominant role in cardiovascular control due to their effects to…

  20. VanderLaan Circulant Type Matrices

    Directory of Open Access Journals (Sweden)

    Hongyan Pan

    2015-01-01

    Full Text Available Circulant matrices have become a satisfactory tools in control methods for modern complex systems. In the paper, VanderLaan circulant type matrices are presented, which include VanderLaan circulant, left circulant, and g-circulant matrices. The nonsingularity of these special matrices is discussed by the surprising properties of VanderLaan numbers. The exact determinants of VanderLaan circulant type matrices are given by structuring transformation matrices, determinants of well-known tridiagonal matrices, and tridiagonal-like matrices. The explicit inverse matrices of these special matrices are obtained by structuring transformation matrices, inverses of known tridiagonal matrices, and quasi-tridiagonal matrices. Three kinds of norms and lower bound for the spread of VanderLaan circulant and left circulant matrix are given separately. And we gain the spectral norm of VanderLaan g-circulant matrix.

  1. Nitrate reduction in an unconfined sandy aquifer

    DEFF Research Database (Denmark)

    Postma, Diederik Jan; Boesen, Carsten; Kristiansen, Henning;

    1991-01-01

    in the reduced zone of the aquifer are organic matter, present as reworked brown coal fragments from the underlying Miocene, and small amounts of pyrite at an average concentration of 3.6 mmol/kg. Electron balances across the redoxcline, based on concentrations of O2, NO3-, SO4(2-) and total inorganic carbon......Nitrate distribution and reduction processes were investigated in an unconfined sandy aquifer of Quaternary age. Groundwater chemistry was studied in a series of eight multilevel samplers along a flow line, deriving water from both arable and forested land. Results show that plumes of nitrate......-contaminated groundwater emanate from the agricultural areas and spread through the aquifer. The aquifer can be subdivided into an upper 10- to 15-m thick oxic zone that contains O2 and NO3-, and a lower anoxic zone characterized by Fe2+-rich waters. The redox boundary is very sharp, which suggests that reduction...

  2. Nitrate intake from drinking water on Tenerife island (Spain).

    Science.gov (United States)

    Caballero Mesa, J M; Rubio Armendáriz, C; Hardisson de la Torre, A

    2003-01-20

    Although meat and vegetable products contain higher concentrations of nitrate, drinking water is the fastest and most direct form of nitrate consumption by the population. It becomes contaminated with nitrates when sea water infiltrates fresh water aquifers and when rain and irrigation water wash through soils that have been excessively treated with nitrated fertilizers. Nitrates are of great toxicological interest as they are involved in the origin of nitrites and nitrosamines and the development of metahaemoglobinaemia in infants. The objective of this study was to determine the quantities of NO(3)(-) in the water supply of each of the Island's municipalities and in the leading brands of bottled waters consumed by the population of Tenerife. This parameter is necessary for the determination of Acceptable Daily Intake (A.D.I.) of nitrates from drinking water. With one unremarkable exception, the nitrate levels found in the water analyzed were optimum for human consumption and amply complied with current European Legislation.

  3. Nitrates - loss processes in raw water

    OpenAIRE

    Hall, G. H.

    1988-01-01

    This project investigated the production of nitrate (nitrification) by bacteria in lakes. The work was undertaken as nitrification is a key process in the nitrogen cycle and previous estimates of rates of nitrification were unreliable. When different methods were used to estimate rates of nitrification within sediment deposits different results were obtained. Investigation' of specific aspects of these methodologies has allowed some rationalization of these observations and also enabled compa...

  4. Genetic basis for nitrate resistance in Desulfovibrio strains

    Directory of Open Access Journals (Sweden)

    Hannah eKorte

    2014-04-01

    Full Text Available Nitrate is an inhibitor of sulfate-reducing bacteria (SRB. In petroleum production sites, amendments of nitrate and nitrite are used to prevent SRB production of sulfide that causes souring of oil wells. A better understanding of nitrate stress responses in the model SRB, Desulfovibrio vulgaris Hildenborough and Desulfovibrio alaskensis G20, will strengthen predictions of environmental outcomes. Nitrate inhibition of SRB has historically been considered to result from the generation of small amounts of nitrite, to which SRB are quite sensitive. Here we explored the possibility that nitrate might inhibit SRB by a mechanism other than through nitrite inhibition. We found that nitrate-stressed D. vulgaris cultures grown in lactate-sulfate conditions eventually grew in the presence of high concentrations of nitrate, and their resistance continued through several subcultures. Nitrate consumption was not detected over the course of the experiment, suggesting adaptation to nitrate. With high-throughput genetic approaches employing TnLE-seq for D. vulgaris and a pooled mutant library of D. alaskensis, we determined the fitness of many transposon mutants of both organisms in nitrate stress conditions. We found that several mutants, including homologs present in both strains, had a greatly increased ability to grow in the presence of nitrate but not nitrite. The mutated genes conferring nitrate resistance included the gene encoding the putative Rex transcriptional regulator (DVU0916/Dde_2702, as well as a cluster of genes (DVU0251-DVU0245/Dde_0597-Dde_0605 that is poorly annotated. Follow-up studies with individual D. vulgaris transposon and deletion mutants confirmed high-throughput results. We conclude that, in D. vulgaris and D. alaskensis, nitrate resistance in wild-type cultures is likely conferred by spontaneous mutations. Furthermore, the mechanisms that confer nitrate resistance may be different from those that confer nitrite resistance.

  5. Organic Nitrates: A Complex Family of Atmospheric Trace Constituents

    Science.gov (United States)

    Ballschmiter, K.; Fischer, R. G.; Grünert, A.; Kastler, J.; Schneider, M.; Woidich, S.

    2003-04-01

    Biogenic and geogenic hydrocarbons are the precursors of organic nitrates that are formed as tropospheric photo-oxidation products in the presence of NOx. Air chemistry leads to a very complex pattern of nitric acid esters: alkyl nitrates, aryl-alkyl nitrates, and bifunctional nitrates like alkyl dinitrates, hydroxy alkyl nitrates and carbonyl alkyl nitrates. We have analyzed the pattern of organic nitrates in air samples after adsorption/thermal desorption (low volume sampling-LVS) or adsorption/solvent desorption (high volume sampling-HVS) by capillary gas chromatography with electron capture (ECD) and mass spectrometric detection (MSD) using air aliquotes of 100 up to 3000 liters on column. The complexity of the organic nitrates found in air requires a group pre-separation by normal phase liquid chromatography. A detection limit per compound of 0.005 ppt(v) is achieved by our approach. We have synthesized a broad spectrum of organic nitrates as reference compounds. Air samples were taken from central Europe, the US West (Utah, Nevada, California), and the North- and South Atlantic including Antarctica. Levels and patterns of the regional and global occurrence of the various groups of C1-C12 organic nitrates including dinitrates and hydroxy nitrates and nitrates of isoprene (2-methylbutadiene) are presented. Werner G., J. Kastler, R. Looser, K. Ballschmiter: "Organic nitrates of isoprene as atmospheric trace compounds" Angewandte Chemie - International Edition (1999) 38: 1634-1637. Woidich S., O. Froescheis, O. Luxenhofer, K. Ballschmiter: "EI- and NCI-mass spectrometry of arylalkyl nitrates and their occurrence in urban air" Fresenius J. Anal. Chem. (1999) 364 : 91-99. Kastler, J; Jarman, W; Ballschmiter, K.: "Multifunctional organic nitrates as constituents in European and US urban photo-smog" Fresenius J. Anal. Chem. (2000) 368:244-249. Schneider M., K. Ballschmiter: "C3-C14 alkyl nitrates in remote South Atlantic air" Chemosphere (1999) 38: 233-244. Fischer

  6. Amperometric nitrate biosensor based on Carbon nanotube/Polypyrrole/Nitrate reductase biofilm electrode.

    Science.gov (United States)

    Can, Faruk; Korkut Ozoner, Seyda; Ergenekon, Pinar; Erhan, Elif

    2012-01-01

    This study describes the construction and characterization of an amperometric nitrate biosensor based on the Polypyrrole (PPy)/Carbon nanotubes (CNTs) film. Nitrate reductase (NR) was both entrapped into the growing PPy film and chemically immobilized via the carboxyl groups of CNTs to the CNT/PPy film electrode. The optimum amperometric response for nitrate was obtained in 0.1 M phosphate buffer solution (PBS), pH 7.5 including 0.1 M lithium chloride and 7 mM potassium ferricyanide with an applied potential of 0.13 V (vs. Ag/AgCl, 3 M NaCl). Sensitivity was found to be 300 nA/mM in a linear range of 0.44-1.45 mM with a regression coefficient of 0.97. The biosensor response showed a higher linear range in comparison to standard nitrate analysis methods which were tested in this study and NADH based nitrate biosensors. A minimum detectable concentration of 0.17 mM (S/N=3) with a relative standard deviation (RSD) of 5.4% (n=7) was obtained for the biosensor. Phenol and glucose inhibit the electrochemical reaction strictly at a concentration of 1 μg/L and 20 mg/L, respectively. The biosensor response retained 70% of its initial response over 10 day usage period when used everyday. PMID:23177766

  7. Radioisotopic evaluation of portal circulation

    International Nuclear Information System (INIS)

    The use of a radio-tracer of portal circulation through the intestine, should prevent cruel punctures in the portal-vein or spleen as it is usually the case with traditional methods in the study of portal-system. The absorption of I-131 and Tc-99m, previously cheked in rabbits presented similar results in dogs. The time of circulation between terminal large-intestine and the liver (t-RF) was determined by external counting at hepatic level by recording radioactivity variation-time. In healthy animals the t-RF was from 20to 60 seconds, with average time of 42 seconds. In 2 animals with partial binding of portal-vein the t-RF went up to 110 and 120 seconds. (Author)

  8. Journalism as Cultures of Circulation

    DEFF Research Database (Denmark)

    Bødker, Henrik

    2013-01-01

    The universe of journalism has always consisted of interspersed texts, meanings and practices. Yet, much journalism research has often isolated either texts and/or contexts and as such assumed relations between professional practices, informed (rational) readers and (conceived) core texts...... of journalism. It is, however, more important than ever to shift attention away from texts to the processes through which they are circulated. This is partly because the many cultural forms of journalism (textual, institutional, technological, material, behavioural and imagined) are undergoing significant......, likes, comments, searches, journalist roles, writing and reading positions and identities etc. Such forms will be traced within the mediation of a specific event with the overall aim of beginning a theorization of the landscape of journalism as highly interrelated cultures of circulation....

  9. Ocean circulation generated magnetic signals

    DEFF Research Database (Denmark)

    Manoj, C.; Kuvshinov, A.; Maus, S.;

    2006-01-01

    Conducting ocean water, as it flows through the Earth's magnetic field, generates secondary electric and magnetic fields. An assessment of the ocean-generated magnetic fields and their detectability may be of importance for geomagnetism and oceanography. Motivated by the clear identification...... of ocean tidal signatures in the CHAMP magnetic field data we estimate the ocean magnetic signals of steady flow using a global 3-D EM numerical solution. The required velocity data are from the ECCO ocean circulation experiment and alternatively from the OCCAM model for higher resolution. We assume...... of the magnetic field, as compared to the ECCO simulation. Besides the expected signatures of the global circulation patterns, we find significant seasonal variability of ocean magnetic signals in the Indian and Western Pacific Oceans. Compared to seasonal variation, interannual variations produce weaker signals....

  10. Reductive denitrification of nitrate by scrap iron filings

    Institute of Scientific and Technical Information of China (English)

    HAO Zhi-wei; XU Xin-hua; WANG Da-hui

    2005-01-01

    Reduction of nitrate by zero-valent iron is a highly exergonic reaction that has long been known to occur. Use of scrap iron filings (SIF) as the PRB (Permeable Reactive Barrier) material can be used to recycle certain by-products, and identify cheaper replacements for expensive conventional PRB materials, especially pure metallic iron. The feasibility of reductive denitrification of nitrate by SIF was studied by batch experiments. Operational parameters such as pH value, SIF dosage and initial concentration of nitrate were investigated. The removal efficiency of nitrate reached 80% under the conditions of pH of 2.5, nitrate initial concentration of 45 mg/L and SIF dosage of 100 g/L within 4 h. Results indicated that nitrate removal is inversely related to pH. Low pH value condition favors for the nitrate transformation. Different from the results of others who studied nitrate reduction using iron powder, we found that there was a lag time before nitrate reduction occurs, even at low pH. Finally, the possible mechanism of nitrate reduction by Fe0 is discussed.

  11. Conservation of circulation in magnetohydrodynamics

    Science.gov (United States)

    Bekenstein; Oron

    2000-10-01

    We demonstrate at both the Newtonian and (general) relativistic levels the existence of a generalization of Kelvin's circulation theorem (for pure fluids) that is applicable to perfect magnetohydrodynamics. The argument is based on the least action principle for magnetohydrodynamic flow. Examples of the new conservation law are furnished. The new theorem should be helpful in identifying new kinds of vortex phenomena distinct from magnetic ropes or fluid vortices. PMID:11089118

  12. Electronic circulation of accounting documents

    OpenAIRE

    Kremláčková, Kateřina

    2014-01-01

    This thesis describes a circulation of accounting documents in an accounting entity, deals with legal requirements of the entire process and discusses it as a part of an internal control system of the entity. In connection with the theme of the work there are also defined legislative conditions for using information and communication technologies and introduced possibilities of involving these technologies in the process of processing of the accounting documents. Above all the electronic data...

  13. Natural circulation systems: advantages and challenges

    International Nuclear Information System (INIS)

    This lecture briefly explains the principle of working of a natural circulation system, its various advantages and applications in nuclear and other industries. The major challenges to be overcome before the wide acceptance of natural circulation as the normal mode of coolant circulation in nuclear power reactors are briefly described. Classification of NCSs and the terminologies commonly encountered in natural circulation literature are also briefly explained. (author)

  14. Nitrate ammonification in mangrove soils: A hidden source of nitrite?

    Directory of Open Access Journals (Sweden)

    Melike eBalk

    2015-03-01

    Full Text Available Nitrate reduction is considered to be a minor microbial pathway in the oxidation of mangrove-derived organic matter due to a limited supply of nitrate in mangrove soils. At a limited availability of this electron acceptor compared to the supply of degradable carbon, nitrate ammonification is thought to be the preferential pathway of nitrate reduction. Mangrove forest mutually differ in their productivity, which may lead to different available carbon to nitrate ratios in their soil. Hence, nitrate ammonification is expected to be of more importance in high- compared to low-productive forests.The hypothesis was tested in flow-through reactors that contain undisturbed mangrove soils from high-productive Avicennia germinans and Rhizophora mangle forests in Florida and low-productive Avicennia marina forests in Saudi Arabia. Nitrate was undetectable in the soils from both regions. It was assumed that a legacy of nitrate ammonification would be reflected by a higher ammonium production from these soils upon the addition of nitrate. Unexpectedly, the soils from the low-productive forests in Saudi Arabia produced considerably more ammonium than the soils from the high-productive forests in Florida. Hence, other environmental factors than productivity must govern the selection of nitrate ammonification or denitrification. A rather intriguing observation was the 1:1 production of nitrite and ammonium during the consumption of nitrate, more or less independent from sampling region, location, sampling depth, mangrove species and from the absence or presence of additional degradable carbon. This 1:1 ratio points to a coupled production of ammonium and nitrite by one group of nitrate-reducing microorganisms. Such a production of nitrite will be hidden under the nitrate-limited conditions of most mangrove forest soils.

  15. Nitrate ammonification in mangrove soils: a hidden source of nitrite?

    KAUST Repository

    Balk, Melike

    2015-03-02

    Nitrate reduction is considered to be a minor microbial pathway in the oxidation of mangrove-derived organic matter due to a limited supply of nitrate in mangrove soils. At a limited availability of this electron acceptor compared to the supply of degradable carbon, nitrate ammonification is thought to be the preferential pathway of nitrate reduction. Mangrove forest mutually differ in their productivity, which may lead to different available carbon to nitrate ratios in their soil. Hence, nitrate ammonification is expected to be of more importance in high- compared to low-productive forests. The hypothesis was tested in flow-through reactors that contain undisturbed mangrove soils from high-productive Avicennia germinans and Rhizophora mangle forests in Florida and low-productive Avicennia marina forests in Saudi Arabia. Nitrate was undetectable in the soils from both regions. It was assumed that a legacy of nitrate ammonification would be reflected by a higher ammonium production from these soils upon the addition of nitrate. Unexpectedly, the soils from the low-productive forests in Saudi Arabia produced considerably more ammonium than the soils from the high-productive forests in Florida. Hence, other environmental factors than productivity must govern the selection of nitrate ammonification or denitrification. A rather intriguing observation was the 1:1 production of nitrite and ammonium during the consumption of nitrate, more or less independent from sampling region, location, sampling depth, mangrove species and from the absence or presence of additional degradable carbon. This 1:1 ratio points to a coupled production of ammonium and nitrite by one group of nitrate-reducing microorganisms. Such a production of nitrite will be hidden by the presence of active nitrite-reducing microorganisms under the nitrate-limited conditions of most mangrove forest soils.

  16. Nitrate ammonification in mangrove soils: a hidden source of nitrite?

    Science.gov (United States)

    Balk, Melike; Laverman, Anniet M; Keuskamp, Joost A; Laanbroek, Hendrikus J

    2015-01-01

    Nitrate reduction is considered to be a minor microbial pathway in the oxidation of mangrove-derived organic matter due to a limited supply of nitrate in mangrove soils. At a limited availability of this electron acceptor compared to the supply of degradable carbon, nitrate ammonification is thought to be the preferential pathway of nitrate reduction. Mangrove forest mutually differ in their productivity, which may lead to different available carbon to nitrate ratios in their soil. Hence, nitrate ammonification is expected to be of more importance in high- compared to low-productive forests. The hypothesis was tested in flow-through reactors that contain undisturbed mangrove soils from high-productive Avicennia germinans and Rhizophora mangle forests in Florida and low-productive Avicennia marina forests in Saudi Arabia. Nitrate was undetectable in the soils from both regions. It was assumed that a legacy of nitrate ammonification would be reflected by a higher ammonium production from these soils upon the addition of nitrate. Unexpectedly, the soils from the low-productive forests in Saudi Arabia produced considerably more ammonium than the soils from the high-productive forests in Florida. Hence, other environmental factors than productivity must govern the selection of nitrate ammonification or denitrification. A rather intriguing observation was the 1:1 production of nitrite and ammonium during the consumption of nitrate, more or less independent from sampling region, location, sampling depth, mangrove species and from the absence or presence of additional degradable carbon. This 1:1 ratio points to a coupled production of ammonium and nitrite by one group of nitrate-reducing microorganisms. Such a production of nitrite will be hidden by the presence of active nitrite-reducing microorganisms under the nitrate-limited conditions of most mangrove forest soils. PMID:25784903

  17. Protein nitration in biological aging: proteomic and tandem mass spectrometric characterization of nitrated sites.

    Science.gov (United States)

    Kanski, Jaroslaw; Schöneich, Christian

    2005-01-01

    Proteomic techniques for the identification of 3-nitrotyrosine-containing proteins in various biological systems are described with emphasis on the direct mass spectrometric detection and sequencing of 3-nitrotyrosine-containing peptides. Strengths and weaknesses of various separation and mass spectrometric techniques are discussed. Some examples for the MS/MS analysis of nitrated peptides obtained from aging rat heart and skeletal muscle are provided, such as nitration of Tyr105 of the mitochondrial electron-transfer flavoprotein and Tyr14 of creatine kinase.

  18. Nitrate Destruction Literature Survey And Evaluation Criteria

    International Nuclear Information System (INIS)

    This report satisfies the initial phase of Task WP-2.3.4 Alternative Sodium Recovery Technology, Subtask 1; Develop Near-Tank Nitrate/Nitrite Destruction Technology. Some of the more common anions in carbon steel waste tanks at SRS and Hanford Site are nitrate which is corrosive, and nitrite and hydroxide which are corrosion inhibitors. At present it is necessary to periodically add large quantities of 50 wt% caustic to waste tanks. There are three primary reasons for this addition. First, when the contents of salt tanks are dissolved, sodium hydroxide preferentially dissolves and is removed. During the dissolution process the concentration of free hydroxide in the tank liquid can decrease from 9 M to less than 0.2 M. As a result, roughly half way through the dissolution process large quantities of sodium hydroxide must be added to the tank to comply with requirements for corrosion control. Second, hydroxide is continuously consumed by reaction with carbon dioxide which occurs naturally in purge air used to prevent buildup of hydrogen gas inside the tanks. The hydrogen is generated by radiolysis of water. Third, increasing the concentration of hydroxide increases solubility of some aluminum compounds, which is desirable in processing waste. A process that converts nitrate and nitrite to hydroxide would reduce certain costs. (1) Less caustic would be purchased. (2) Some of the aluminum solid compounds in the waste tanks would become more soluble so less mass of solids would be sent to High Level Vitrification and therefore it would be not be necessary to make as much expensive high level vitrified product. (3) Less mass of sodium would be fed to Saltstone at SRS or Low Level Vitrification at Hanford Site so it would not be necessary to make as much low level product. (4) At SRS less nitrite and nitrate would be sent to Defense Waste Processing Facility (DWPF) so less formic acid would be consumed there and less hydrogen gas would be generated. This task involves

  19. NITRATE DESTRUCTION LITERATURE SURVEY AND EVALUATION CRITERIA

    Energy Technology Data Exchange (ETDEWEB)

    Steimke, J.

    2011-02-01

    This report satisfies the initial phase of Task WP-2.3.4 Alternative Sodium Recovery Technology, Subtask 1; Develop Near-Tank Nitrate/Nitrite Destruction Technology. Some of the more common anions in carbon steel waste tanks at SRS and Hanford Site are nitrate which is corrosive, and nitrite and hydroxide which are corrosion inhibitors. At present it is necessary to periodically add large quantities of 50 wt% caustic to waste tanks. There are three primary reasons for this addition. First, when the contents of salt tanks are dissolved, sodium hydroxide preferentially dissolves and is removed. During the dissolution process the concentration of free hydroxide in the tank liquid can decrease from 9 M to less than 0.2 M. As a result, roughly half way through the dissolution process large quantities of sodium hydroxide must be added to the tank to comply with requirements for corrosion control. Second, hydroxide is continuously consumed by reaction with carbon dioxide which occurs naturally in purge air used to prevent buildup of hydrogen gas inside the tanks. The hydrogen is generated by radiolysis of water. Third, increasing the concentration of hydroxide increases solubility of some aluminum compounds, which is desirable in processing waste. A process that converts nitrate and nitrite to hydroxide would reduce certain costs. (1) Less caustic would be purchased. (2) Some of the aluminum solid compounds in the waste tanks would become more soluble so less mass of solids would be sent to High Level Vitrification and therefore it would be not be necessary to make as much expensive high level vitrified product. (3) Less mass of sodium would be fed to Saltstone at SRS or Low Level Vitrification at Hanford Site so it would not be necessary to make as much low level product. (4) At SRS less nitrite and nitrate would be sent to Defense Waste Processing Facility (DWPF) so less formic acid would be consumed there and less hydrogen gas would be generated. This task involves

  20. Internal variability of the thermohaline ocean circulation

    NARCIS (Netherlands)

    Raa, Lianke Alinda te

    2003-01-01

    Variations in the ocean circulation can strongly influence climate due to the large heat transport by the ocean currents. Variability of the thermohaline ocean circulation, the part of the ocean circulation driven by density gradients, occurs typically on (inter)decadal and longer time scales and is

  1. Evaluating Ecosystem Services for Reducing Groundwater Nitrate Contamination: Nitrate Attenuation in the Unsaturated and Saturated Zones

    Science.gov (United States)

    Wang, J.

    2013-12-01

    Nitrates are the most common type of groundwater contamination in agricultural regions. Environmental policies targeting nitrates have focused on input control (e.g., restricted fertilizer application), intermediate loads control (e.g., reduce nitrate leached from crop fields), and final loads control (e.g., reduce catchment nitrate loads). Nitrate loads can be affected by hydrological processes in both unsaturated and saturated zones. Although many of these processes have been extensively investigated in literature, they are commonly modeled as exogenous to farm management. A couple of recent studies by scientists from the Lawrence Livermore National Laboratory show that in some situations nitrate attenuation processes in the unsaturated/saturated zone, particularly denitrification, can be intensified by certain management practices to mitigate nitrate loads. Therefore, these nitrate attenuation processes can be regarded as a set of ecosystem services that farmers can take advantage of to reduce their cost of complying with environmental policies. In this paper, a representative California dairy farm is used as a case study to show how such ecosystem attenuation services can be framed within the farm owner's decision-making framework as an option for reducing groundwater nitrate contamination. I develop an integrated dynamic model, where the farmer maximizes discounted net farm profit over multiple periods subject to environmental regulations. The model consists of three submodels: animal-waste-crop, hydrologic, and economic model. In addition to common choice variables such as irrigation, fertilization, and waste disposal options, the farmer can also endogenously choose from three water sources: surface water, deep groundwater (old groundwater in the deep aquifer that is not affected by farm effluent in the short term), and shallow groundwater (drainage water that can be recycled via capture wells at the downstream end of the farm). The capture wells not only

  2. Accumulation of Nitrate in Vegetables and Its Possible Implications to Human Health

    Institute of Scientific and Technical Information of China (English)

    DU Shao-ting; ZHANG Yong-song; LIN Xian-yong

    2007-01-01

    In recent times, there are two kinds of completely opposite viewpoints about the impacts of nitrate on human health. To further objectively understand the effects of nitrate on human health, both of harmfulness and possible benefits of nitrate to human body, it is discussed in this review from the aspects of nitrate accumulation in vegetables, the source of nitrate ingested into human body, and the transformation of nitrate in human body, as well as the pathogenesis and physiological functions of nitrate metabolism.

  3. Impact of weather variability on nitrate leaching

    Science.gov (United States)

    Richards, Karl; Premrov, Alina; Hackett, Richard; Coxon, Catherine

    2016-04-01

    The loss of nitrate (NO3 - N) to water via leaching and overland flow contributes to eutrophication of freshwaters, transitional and near coastal waters with agriculture contributing significantly to nitrogen (N) loading to these water. Environmental regulations, such as the Nitrates and Water Framework Directives, have increased constraints on farmers to improve N management in regions at risk of NO3--N loss to water. In addition, farmers also have to manage their systems within a changing climate as the imapcts of climate change begin to impact resulting in more frequent extreme events such as floods and droughts. The objective of this study was to investigate the link between weather volatility and the concentration of leached NO3--N spring barley. Leaching was quantified under spring barley grown on a well-drained, gravelly sandy soil using ceramic cup samplers over 6 drainage years under the same farming practices and treatments. Soil solution NO3--N concentrations under spring barley grown by conventional inversion ploughing and reduced tillage were compared to weather parameters over the period. Weather was recorded at a national Met Eireann weather station on site. Soil solution NO3--N varied significantly between years. Within individual years NO3--N concentrations varied over the drainage season, with peak concentrations generally observed in the autumn time, decreasing thereafter. Under both treatments there was a three-fold difference in mean annual soil solution NO3--N concentration over the 6 years with no change in the agronomic practices (crop type, tillage type and fertiliser input). Soil solution nitrate concentrations were significantly influenced by weather parameters such as rainfall, effective drainage and soil moisture deficit. The impact of climate change in Ireland could lead to increased NO3--N loss to water further exacerbating eutrophication of sensitive estuaries. The increased impact on eutrophication of waters, related to climatic

  4. Sustainability of natural attenuation of nitrate in agricultural aquifers

    Science.gov (United States)

    Green, Christopher T.; Bekins, Barbara A.

    2010-01-01

    Increased concentrations of nitrate in groundwater in agricultural areas, coinciding with increased use of chemical and organic fertilizers, have raised concern because of risks to environmental and human health. At some sites, these problems are mitigated by natural attenuation of nitrate as a result of microbially mediated reactions. Results from U.S. Geological Survey (USGS) research under the National Water-Quality Assessment (NAWQA) program show that reactions of dissolved nitrate with solid aquifer minerals and organic carbon help lower nitrate concentrations in groundwater beneath agricultural fields. However, increased fluxes of nitrate cause ongoing depletion of the finite pool of solid reactants. Consumption of the solid reactants diminishes the capacity of the aquifer to remove nitrate, calling into question the long-term sustainability of these natural attenuation processes.

  5. Periplasmic nitrate reductases: structural and spectroscopic studies

    OpenAIRE

    Javier Gonzalez, Pablo

    2006-01-01

    Dissertação apresentada para obtenção do grau de Doutor em Bioquímica, especialidade Bioquímica-Física, pela Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa Nitrate reduction occurs in the cell in order to incorporate nitrogen into biomolecules(assimilatory ammonification), as the final electron acceptor when bacteria are grown in anaerobic conditions (denitrification/dissimilatory ammonification) and to eliminate energy excess generated by the cell metabolism (dissimi...

  6. Electrospun cellulose nitrate and polycaprolactone blended nanofibers

    Science.gov (United States)

    Nartker, Steven; Hassan, Mohamed; Stogsdill, Michael

    2015-03-01

    Pure cellulose nitrate (CN) and blends of CN and polycaprolactone were electrospun to form nonwoven mats. Polymers were dissolved in a mixed solvent system of tetrahydrofuran and N,N-dimethylformamide. The concentrations were varied to obtain sub-micron and nanoscale fiber mats. Fiber mats were analyzed using scanning electron microscopy, contact angle analysis, Fourier transform infrared spectroscopy and thermal gravimetric analysis. The fiber morphology, surface chemistry and contact angle data show that these electrospun materials are suitable for applications including biosensing, biomedical and tissue engineering.

  7. Biological denitrification of nitrate waste solutions

    International Nuclear Information System (INIS)

    The studies leading to the design of the Oak Ridge Y-12 plant biological denitrification system are briefly described. The system uses a flow-through stirred-bed reactor. Methanol and lime-neutralized acetic acid were evaluated as C sources. The acetic acid was selected because the calcium carbonate generated in the process is needed for neutralization of the acid wastes. Excess organic will be used to ensure maximum amount of nitrate destroyed. The system will generate solids in the form of calcium carbonate, aluminum hydroxide, and organic carbon and N2 and CO2 gases. (JSR)

  8. Nitrate reduction in geologically heterogeneous catchments

    DEFF Research Database (Denmark)

    Refsgaard, Jens Christian; Auken, Esben; Bamberg, C.A.;

    2014-01-01

    and for assessing at which spatial scales modelling tools have predictive capabilities. A new instrument has been developed for airborne geophysical measurements, Mini-SkyTEM, dedicated to identifying geological structures and heterogeneities with horizontal and lateral resolutions of 30–50 m and 2 m, respectively...... the entire catchment. However, as distributed models often do not include local scale hydrogeological heterogeneities, they are typically not able to make accurate predictions at scales smaller than they are calibrated. We present a framework for assessing nitrate reduction in the subsurface...

  9. Simple approximation of nitrate diffusion from saltstone

    International Nuclear Information System (INIS)

    This report describes: (1) The justification for using one dimensional semi-infinite solid, with zero surface concentration, as an adequate model for saltstone leaching. (2) A simplified model involving leaching from a monolith into a well stirred tank to describe the transient salt concentration in the soil as the water in it migrates toward the saturated zone. (3) The effect, on the flux of sodium nitrate into the soil, of a slab of material such as clay or cement, placed between the saltstone and soil. It is assumed that the material in intermediate between that of the saltstone and soil

  10. Nitrate pollution in groundwater: source identification using isotope ratio

    International Nuclear Information System (INIS)

    Isotope ratios for identification of pollutant source is an emerging scientific tool. An investigation was carried out to find out the origin of nitrate in groundwater in an area which receives pollutant of different origin like inorganic fertilizers, organic manures besides urban wastes. The δ15N values of nitrate clearly indicated the possibility of groundwater pollution by nitrate originating from human and animal wastes. (author)

  11. Effects of long-term dietary nitrate supplementation in mice

    OpenAIRE

    Hezel, Michael P.; Ming Liu; Tomas A. Schiffer; Larsen, Filip J.; Antonio Checa; Wheelock, Craig E; Mattias Carlström; Lundberg, Jon O.; Eddie Weitzberg

    2015-01-01

    Background: Inorganic nitrate (NO3-) is a precursor of nitric oxide (NO) in the body and a large number of short-term studies with dietary nitrate supplementation in animals and humans show beneficial effects on cardiovascular health, exercise efficiency, host defense and ischemia reperfusion injury. In contrast, there is a long withstanding concern regarding the putative adverse effects of chronic nitrate exposure related to cancer and adverse hormonal effects. To address these concerns we p...

  12. Nitrate paradigm does not hold up for sugarcane.

    Directory of Open Access Journals (Sweden)

    Nicole Robinson

    Full Text Available Modern agriculture is based on the notion that nitrate is the main source of nitrogen (N for crops, but nitrate is also the most mobile form of N and easily lost from soil. Efficient acquisition of nitrate by crops is therefore a prerequisite for avoiding off-site N pollution. Sugarcane is considered the most suitable tropical crop for biofuel production, but surprisingly high N fertilizer applications in main producer countries raise doubt about the sustainability of production and are at odds with a carbon-based crop. Examining reasons for the inefficient use of N fertilizer, we hypothesized that sugarcane resembles other giant tropical grasses which inhibit the production of nitrate in soil and differ from related grain crops with a confirmed ability to use nitrate. The results of our study support the hypothesis that N-replete sugarcane and ancestral species in the Andropogoneae supertribe strongly prefer ammonium over nitrate. Sugarcane differs from grain crops, sorghum and maize, which acquired both N sources equally well, while giant grass, Erianthus, displayed an intermediate ability to use nitrate. We conclude that discrimination against nitrate and a low capacity to store nitrate in shoots prevents commercial sugarcane varieties from taking advantage of the high nitrate concentrations in fertilized soils in the first three months of the growing season, leaving nitrate vulnerable to loss. Our study addresses a major caveat of sugarcane production and affords a strong basis for improvement through breeding cultivars with enhanced capacity to use nitrate as well as through agronomic measures that reduce nitrification in soil.

  13. Nitrate paradigm does not hold up for sugarcane.

    Science.gov (United States)

    Robinson, Nicole; Brackin, Richard; Vinall, Kerry; Soper, Fiona; Holst, Jirko; Gamage, Harshi; Paungfoo-Lonhienne, Chanyarat; Rennenberg, Heinz; Lakshmanan, Prakash; Schmidt, Susanne

    2011-01-01

    Modern agriculture is based on the notion that nitrate is the main source of nitrogen (N) for crops, but nitrate is also the most mobile form of N and easily lost from soil. Efficient acquisition of nitrate by crops is therefore a prerequisite for avoiding off-site N pollution. Sugarcane is considered the most suitable tropical crop for biofuel production, but surprisingly high N fertilizer applications in main producer countries raise doubt about the sustainability of production and are at odds with a carbon-based crop. Examining reasons for the inefficient use of N fertilizer, we hypothesized that sugarcane resembles other giant tropical grasses which inhibit the production of nitrate in soil and differ from related grain crops with a confirmed ability to use nitrate. The results of our study support the hypothesis that N-replete sugarcane and ancestral species in the Andropogoneae supertribe strongly prefer ammonium over nitrate. Sugarcane differs from grain crops, sorghum and maize, which acquired both N sources equally well, while giant grass, Erianthus, displayed an intermediate ability to use nitrate. We conclude that discrimination against nitrate and a low capacity to store nitrate in shoots prevents commercial sugarcane varieties from taking advantage of the high nitrate concentrations in fertilized soils in the first three months of the growing season, leaving nitrate vulnerable to loss. Our study addresses a major caveat of sugarcane production and affords a strong basis for improvement through breeding cultivars with enhanced capacity to use nitrate as well as through agronomic measures that reduce nitrification in soil. PMID:21552564

  14. A nitrate sensitive planar optode; performance and interferences

    DEFF Research Database (Denmark)

    Pedersen, Lasse; Dechesne, Arnaud; Smets, Barth F.

    2015-01-01

    We present a newly developed nitrate sensitive planar optode. It exhibits a linear response to nitrate from 1 to 50 mM at pH 8.0, a fast response time below 10 s and a good lifetime, allowing for fast two dimensional nitrate measurements over long periods of time. Interference from nitrite, chlor......, chloride and thiocyanate, however, limits the optode's application in environments where these are encountered, notably seawater with its high chloride content....

  15. NITRATE AND NITRITE CONCENTRATION IN VEGETABLES GRAWING AROUND ISFAHAN CITY

    OpenAIRE

    R.A JAFARI; A AZIZ ZADEH; A FARZAN

    2001-01-01

    Introduction: The improper and excess use of chemical fertilizers by the farmers special in "urea" form may cause the commulation of nitrates and nitrites in vegetables and fruits. This investigation has been done to determine the concentration of nitrates and nitrites in some vegetables growing around Isfahan. Methods: One hundred and thirteen random samples from 15 different kinds of green lest tuber vegetables were measured by Cadmium Column Procedure for nitrates and nitrites. R...

  16. Impacts of drainage water management on subsurface drain flow, nitrate concentration, and nitrate loads in Indiana

    Science.gov (United States)

    Drainage water management is a conservation practice that has the potential to reduce drainage outflow and nitrate (NO3) loss from agricultural fields while maintaining or improving crop yields. The goal of this study was to quantify the impact of drainage water management on dra...

  17. Circulating follistatin in relation to energy metabolism.

    Science.gov (United States)

    Hansen, Jakob Schiøler; Plomgaard, Peter

    2016-09-15

    Recently, substantial evidence has emerged that the liver contributes significantly to the circulating levels of follistatin and that circulating follistatin is tightly regulated by the glucagon-to-insulin ratio. Both observations are based on investigations of healthy subjects. These novel findings challenge the present view of circulating follistatin in human physiology, being that circulating follistatin is a result of spill-over from para/autocrine actions in various tissues and cells. Follistatin as a liver-derived protein under the regulation of glucagon-to-insulin ratio suggests a relation to energy metabolism. In this narrative review, we attempt to reconcile the existing findings on circulating follistatin with the novel concept that circulating follistatin is a liver-derived molecule regulated by the glucagon-to-insulin ratio. The picture emerging is that conditions associated with elevated levels of circulating follistatin have a metabolic denominator with decreased insulin sensitivity and/or hyperglucagoneimia. PMID:27264073

  18. Regioselective nitration of aromatic substrates in zeolite cages

    Indian Academy of Sciences (India)

    T Esakkidurai; M Kumarraja; K Pitchumani

    2003-04-01

    Phenol is nitrated regioselectively by fuming nitric acid inside the cages of faujasite zeolites (dependent on the loading level) and a remarkable orthoselectivity is observed in solid state nitration. Toluene and chlorobenzene also containing ortho-/para-orienting substituents, undergo faster nitration, though the regioselectivity is less significant in zeolite media. The results are explained on the basis of diffusion and binding of phenol inside zeolite, which facilitate regioselectivity (and which is absent in toluene and chlorobenzene). Other advantages of employing zeolites as media for mild and selective nitration are also highlighted.

  19. Anoxic Activated Sludge Monitoring with Combined Nitrate and Titrimetric Measurements

    DEFF Research Database (Denmark)

    Petersen, B.; Gernaey, Krist; Vanrolleghem, P.A.

    2002-01-01

    An experimental procedure for anoxic activated sludge monitoring with combined nitrate and titrimetric measurements is proposed and evaluated successfully with two known carbon sources, (-)acetate and dextrose. For nitrate measurements an ion-selective nitrate electrode is applied to allow...... was with the carbon source in excess, since excess nitrate provoked nitrite build-up thereby complicating the data interpretation. A conceptual model could quantitatively describe the experimental observations and thus link the experimentally measured proton production with the consumption of electron acceptor...... and carbon source during denitrification....

  20. Development of technology for ammonium nitrate dissociation process

    International Nuclear Information System (INIS)

    Ammonia and ammonium carbonate are frequently used as reagents in fuel production and processing of liquid radioactive wastes. In particular, liquid radioactive wastes that contain ammonium nitrate are generated during operations of metal precipitation. In closed vessels at elevated temperature, for example in evaporators or deposits in tubing, ammonium nitrate may explode due to generation of gaseous nitrogen oxides [2]. In this connection, steps have to be taken to rule out conditions that result in explosion. To do that, ammonium nitrate should be removed even prior to the initial stage of its formation. This report gives results of development of a method of dissociating ammonium nitrate

  1. Significant accumulation of nitrate in Chinese semi-humid croplands

    Science.gov (United States)

    Zhou, Junyu; Gu, Baojing; Schlesinger, William H.; Ju, Xiaotang

    2016-04-01

    Soil nitrate is important for crop growth, but it can also leach to groundwater causing nitrate contamination, a threat to human health. Here, we report a significant accumulation of soil nitrate in Chinese semi-humid croplands based upon more than 7000 samples from 141 sites collected from 1994 to 2015. In the 0-4 meters depth of soil, total nitrate accumulation reaches 453 ± 39, 749 ± 75, 1191 ± 89, 1269 ± 114, 2155 ± 330 kg N ha-1 on average in wheat, maize, open-field vegetables (OFV), solar plastic-roofed greenhouse vegetables (GHV) and orchard fields, respectively. Surprisingly, there is also a comparable amount of nitrate accumulated in the vadose-zone deeper than 4 meters. Over-use of N fertilizer (and/or manure) and a declining groundwater table are the major causes for this huge nitrate reservoir in the vadose-zone of semi-humid croplands, where the nitrate cannot be denitrified due to the presence of oxygen and lack of carbon sources. Future climatic change with more extreme rainfall events would increase the risk of accumulated nitrate moving downwards and threatening groundwater nitrate contamination.

  2. Hydrothermal oxidation of organic wastes using reclaimed ammonium nitrate

    Energy Technology Data Exchange (ETDEWEB)

    Proesmans, P.I.; Luan, L.; Buelow, S.J.

    1996-04-01

    Ammonium nitrate is being studied as an alternative for ammonium perchlorate as an oxidizing agent in Department of Defense 1.1 and 1.3 rocket propellants. Use of ammonium nitrate would eliminate the HCl produced by ammonium perchlorate upon thermal decomposition. To stabilize the ammonium nitrate, which suffers from phase instability, potassium dinitramide (KDN) is added. This increased use of ammonium nitrate will ultimately create a need for environmentally responsible processes to reuse ammonium nitrate extracted from demilitarized rocket motors. Ammonium Nitrate was investigated as an oxidizing agent for methanol, acetic acid and phenol. High removal of organic, ammonia and nitrate was achieved at stoichiometric concentrations. The oxidation of ammonia by nitrate was much faster than the oxidation of either methanol or acetic acid. Phenol, however, was in strong competition with ammonia for the oxidizer (nitrate). Nitrogen products included N{sub 2}, N{sub 2}O, NO{sub 2{sup {minus}}} as well as toxic NO and trace amounts of NO{sub 2}. Carbon products were CO{sub 2}, HCO{sub 3{sup {minus}}}, CO{sub 3}{sup 2{minus}}, and CO.

  3. Thermal decomposition of supported lithium nitrate catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz, Maria Lucia [INTEQUI (CONICET-UNSL), 25 de Mayo 384, V. Mercedes, 5730, San Luis (Argentina); Lick, Ileana Daniela [CINDECA (CONICET-UNLP), Calle 47 No 257, La Plata, 1900, Buenos Aires (Argentina); Ponzi, Marta Isabel [INTEQUI (CONICET-UNSL), 25 de Mayo 384, V. Mercedes, 5730, San Luis (Argentina); Castellon, Enrique Rodriguez; Jimenez-Lopez, Antonio [Departamento de Quimica Inorganica, Cristalografia y Mineralogia. Facultad de Ciencias, Universidad de Malaga, Campus de Teatinos, 29071 Malaga (Spain); Ponzi, Esther Natalia, E-mail: eponzi@quimica.unlp.edu.ar [CINDECA (CONICET-UNLP), Calle 47 No 257, La Plata, 1900, Buenos Aires (Argentina)

    2010-02-20

    New catalysts for soot combustion were prepared by impregnation of different supports (SiO{sub 2}, ZrO{sub 2} and ZrO{sub 2}.nH{sub 2}O) with a LiNO{sub 3} solution and then characterized by means of FTIR, XPS, TGA and UV-vis spectroscopy, whereby the presence of lithium nitrate in the prepared catalysts was identified and quantified. The soot combustion rate using this series of catalysts (LiNO{sub 3}/support) was compared with the activity of a series of impregnated catalysts prepared using LiOH (Li{sub 2}O/supports). Catalysts prepared using LiNO{sub 3} are found to be more active than those prepared using LiOH. The catalytic performance was also studied with a NO/O{sub 2} mixture in the feed, demonstrating that NO increases the combustion rate of soot, probably as a consequence of lithium oxide forming an 'in situ' nitrate ion.

  4. New infrared spectroscopic database for bromine nitrate

    Science.gov (United States)

    Wagner, Georg; Birk, Manfred

    2016-08-01

    Fourier transform infrared measurements of bromine nitrate have been performed in the spectral region 675-1400 cm-1 at 0.014 cm-1 spectral resolution. Absorption cross sections were derived from 38 spectra covering the temperature range from 203 to 296 K and air pressure range from 0 to 190 mbar. For line-by-line analysis, further spectra were recorded at 0.00094 cm-1 spectral resolution at 223 and 293 K. The sample was synthesized from ClONO2 and Br2. Band strengths of the bands ν3 around 803 cm-1 and ν2 around 1286 cm-1 were determined from three pure BrONO2 measurements at different temperatures and pressures. Number densities in the absorption cell were derived from pressure measurements of the purified sample taking into account small amounts of impurities determined spectroscopically. Resulting band strengths are Sν3 = 2.872(52) × 10-17 cm2 molec-1 cm-1 and Sν2 = 3.63(15) × 10-17 cm2 molec-1 cm-1. Absorption cross sections of all measurements were scaled to these band strengths. Further data reduction was achieved with an interpolation scheme based on two-dimensional polynomials in ln(pressure) and temperature. The database is well-suited for remote-sensing application and should reduce the atmospheric bromine nitrate error budget substantially.

  5. Cement encapsulation of uranyl nitrate waste

    International Nuclear Information System (INIS)

    During decontamination of the former nuclear fuel reprocessing plant at West Valley, New York, low-level radioactive waste streams are being identified which require disposal in an environmentally acceptable manner. One such waste stream, consisting essentially of uranyl nitrate, has been located in one of the processing cells. A study was conducted on this waste stream to determine if it could be stably encapsulated in cement. First, a recipe was developed for cement-encapsulating this highly acidic waste. Samples were then made to perform waste qualification testing as described in the NRC Branch Technical Position-Waste Form to determine the stability of this waste form. The testing showed that the waste form had a compressive strength much greater than the 345 kPA (50 psi) minimum guideline after room-temperature cure, irradiation, thermal cycling, immersion, and biodegradation. In addition, the encapsulated waste had uranium and cerium leachability index values greater than six, which is the minimum recommended by the NRC position paper. The cement-encapsulated uranyl nitrate waste thus met the NRC stability guidelines for the disposal of Class B and Class C radioactive wastes

  6. A modified procedure for measuring oxygen-18 content of nitrate

    Science.gov (United States)

    Ahmed, M. A.; Aly, A. I. M.; Abdel Monem, N.; Hanafy, M.; Gomaa, H. E.

    2012-11-01

    SummaryMass spectrometric analysis of O-isotopic composition of nitrate has many potential applications in studies of environmental processes. Through this work, rapid, reliable, precise, broadly applicable, catalyst-free, low-priced and less labor intensive procedure for measuring δ18O of nitrate using Isotope Ratio Mass Spectrometer has been developed and implemented. The conditions necessary to effect complete nitrate recovery and complete removal of other oxygen containing anions and dissolved organic carbon (DOC) without scarifying the isotopic signature of nitrate were investigated. The developed procedure consists of two main parts: (1) wet chemistry train for extraction and purification of nitrate from the liquid matrix; (2) off-line pyrolysis of extracted nitrate salt with activated graphite at 550 °C for 30 min. The conditions necessary to effect complete nitrate recovery and complete removal of other oxygen containing compounds were investigated. Dramatic reduction in processing times needed for analysis of δ18O of nitrate at natural abundance level was achieved. Preservation experiments revealed that chloroform (99.8%) is an effective preservative. Isotopic contents of some selected nitrate salts were measured using the modified procedure and some other well established methods at two laboratories in Egypt and Germany. Performance assessment of the whole developed analytical train was made using internationally distributed nitrate isotopes reference materials and real world sample of initial zero-nitrate content. The uncertainty budget was evaluated using the graphical nested hierarchal approach. The obtained results proved the suitability for handling samples of complicated matrices. Reduction of consumables cost by about 80% was achieved.

  7. Heat transfer behavior of molten nitrate salt

    Science.gov (United States)

    Das, Apurba K.; Clark, Michael M.; Teigen, Bard C.; Fiveland, Woodrow A.; Anderson, Mark H.

    2016-05-01

    The usage of molten nitrate salt as heat transfer fluid and thermal storage medium decouples the generation of electricity from the variable nature of the solar resource, allowing CSP plants to avoid curtailment and match production with demand. This however brings some unique challenges for the design of the molten salt central receiver (MSCR). An aspect critical to the use of molten nitrate (60wt%/40wt% - NaNO3/KNO3) salt as heat transfer fluid in the MSCR is to understand its heat transfer behavior. Alstom collaborated with the University of Wisconsin to conduct a series of experiments and experimentally determined the heat transfer coefficients of molten nitrate salt up to high Reynolds number (Re > 2.0E5) and heat flux (q″ > 1000 kW/m2), conditions heretofore not reported in the literature. A cartridge heater instrumented with thermocouples was installed inside a stainless steel pipe to form an annular test section. The test section was installed in the molten salt flow loop at the University of Wisconsin facility, and operated over a range of test conditions to determine heat transfer data that covered the expected operating regime of a practical molten salt receiver. Heat transfer data were compared to widely accepted correlations found in heat transfer literature, including that of Gnielinski. At lower Reynolds number conditions, the results from this work concurred with the molten salt heat transfer data reported in literature and followed the aforementioned correlations. However, in the region of interest for practical receiver design, the correlations did not accurately model the experimentally determined heat transfer data. Two major effects were observed: (i) all other factors remaining constant, the Nusselt numbers gradually plateaued at higher Reynolds number; and (ii) at higher Reynolds number a positive interaction of heat flux on Nusselt number was noted. These effects are definitely not modeled by the existing correlations. In this paper a new

  8. Spatial assessment of animal manure spreading and groundwater nitrate pollution

    Directory of Open Access Journals (Sweden)

    Roberta Infascelli

    2009-11-01

    Full Text Available Nitrate concentration in groundwater has frequently been linked to non-point pollution. At the same time the existence of intensive agriculture and extremely intensive livestock activity increases the potential for nitrate pollution in shallow groundwater. Nitrate used in agriculture could cause adverse effects on human and animal health. In order to evaluate the groundwater nitrate pollution, and how it might evolve in time, it is essential to develop control systems and to improve policies and incentives aimed at controlling the amount of nitrate entering downstream water systems. The province of Caserta in southern Italy is characterized by high levels of animal manure loading. A comparison between manure nitrogen production and nitrate concentration in groundwater was carried out in this area, using geostatistical tools and spatial statistics. The results show a discrepancy between modelling of nitrate leaching and monitoring of the groundwater and, moreover, no spatial correlation between nitrogen production in livestock farms and nitrate concentration in groundwater, suggesting that producers are not following the regulatory procedures for the agronomic use of manure. The methodology developed in this paper could be applied also in other regions in which European Union fertilization plans are not adequately followed.

  9. Iron-mediated effects on nitrate reductase in marine phytoplankton

    NARCIS (Netherlands)

    Timmermans, K.R.; Stolte, W.; Baar, H.J.W. de

    1994-01-01

    The potential activity of nitrate reductase was determined in uni-algal cultures in the laboratory and in natural marine phytoplankton assemblages. In the laboratory bioassays, distinct differences in nitrate reductase activity were observed in iron replete versus depleted cultures for Emiliania hux

  10. Nitrate sorption and desorption in biochars from fast pyrolysis

    Science.gov (United States)

    Increasing the nitrate (NO3-) sorption capacity of Midwestern US soils has the potential to reduce nitrate leaching to ground water and reduce the extent of the hypoxia zone in the Gulf of Mexico. The objective of this study was to determine the sorption and desorption capacity of non-activated and ...

  11. Is nitrate an endocrine active compound in fish?

    DEFF Research Database (Denmark)

    Mose, M. P.; Kinnberg, Karin Lund; Bjerregaard, Poul;

    concentrations around or below the limits for drinking water). Nitrate concentrations in streams may be elevated due to releases from agricultural practices. The effects of nitrate and nitrite on endocrine relevant endpoints were investigated in zebrafish (Danio rerio) and brown trout (Salmo trutta). Zebrafish...

  12. Predicting SOA from organic nitrates in the southeastern United States

    Science.gov (United States)

    Organic nitrates have been identified as an important component of ambient aerosol in the Southeast United States. In this work, we use the Community Multiscale Air Quality (CMAQ) model to explore the relationship between gas-phase production of organic nitrates and their subsequ...

  13. Distribution and Sources of Nitrate-Nitrogen in Kansas Groundwater

    Directory of Open Access Journals (Sweden)

    Margaret A. Townsend

    2001-01-01

    Full Text Available Kansas is primarily an agricultural state. Irrigation water and fertilizer use data show long- term increasing trends. Similarly, nitrate-N concentrations in groundwater show long-term increases and exceed the drinking-water standard of 10 mg/l in many areas. A statistical analysis of nitrate-N data collected for local and regional studies in Kansas from 1990 to 1998 (747 samples found significant relationships between nitrate-N concentration with depth, age, and geographic location of wells. Sources of nitrate-N have been identified for 297 water samples by using nitrogen stable isotopes. Of these samples, 48% showed fertilizer sources (+2 to +8 and 34% showed either animal waste sources (+10 to +15 with nitrate-N greater than 10 mg/l or indication that enrichment processes had occurred (+10 or above with variable nitrate-N or both. Ultimate sources for nitrate include nonpoint sources associated with past farming and fertilization practices, and point sources such as animal feed lots, septic systems, and commercial fertilizer storage units. Detection of nitrate from various sources in aquifers of different depths in geographically varied areas of the state indicates that nonpoint and point sources currently impact and will continue to impact groundwater under current land uses.

  14. Evaluation of nitrate and nitrite destruction/separation technologies

    Energy Technology Data Exchange (ETDEWEB)

    Hobbs, D.T.

    1997-08-29

    This report describes and evaluates four types of nitrate and nitrite destruction and separation technologies that could be used to treat the aqueous, alkaline, nitrate-bearing mixed waste that is generated by the In-Tank Precipitation (ITP) process at the Savannah River Site (SRS). The technologies considered in this report include thermal, hydrothermal, chemical, and electrochemical technologies.

  15. Nitrate leaching and pesticide use in energy crops

    DEFF Research Database (Denmark)

    Jørgensen, Uffe

    2006-01-01

    Nitrate leaching measured below willow and miscanthus is very low from the established crops. Pesticide use in energy crops is low as well.......Nitrate leaching measured below willow and miscanthus is very low from the established crops. Pesticide use in energy crops is low as well....

  16. CU(II): catalyzed hydrazine reduction of ferric nitrate

    International Nuclear Information System (INIS)

    A method is described for producing ferrous nitrate solutions by the cupric ion-catalyzed reduction of ferric nitrate with hydrazine. The reaction is complete in about 1.5 hours at 400C. Hydrazoic acid is also produced in substantial quantities as a reaction byproduct

  17. NITRITE AND NITRATE DETERMINATIONS IN PLASMA - A CRITICAL-EVALUATION

    NARCIS (Netherlands)

    MOSHAGE, H; KOK, B; HUIZENGA, [No Value; JANSEN, PLM

    1995-01-01

    Plasma nitrite and nitrate determinations are increasingly being used in clinical chemistry as markers for the activity of nitric oxide synthase and the production of nitric oxide radicals. However, a systematic evaluation of the determination of nitrite and nitrate in plasma has not been performed.

  18. Effects of sludge disposal on groundwater nitrate concentrations

    Science.gov (United States)

    Spalding, R. F.; Exner, M. E.; Martin, G. E.; Snow, D. D.

    1993-02-01

    More than 100 groundwater samples were collectd and analyzed for nitrate-nitrogen, δ 15N of the nitrate, dissolved organic carbon (DOC), and chloride. Multilevel samplers and nested monitoring wells were located beneath and down-gradient from an irrigated cornfield on which human waste sludge was injected. The sampling delineated a 1.3km× 0.3km plume of nitrate contamination. Both the nitrate-nitrogen concentrations and the δ 15N values within the plume's centroid were homogeneous. The levels were 34 ± 3mg1 -1 and + 13.4 ± 1.2%, respectively. A retarding zone of clayey silt split the plume and separated the oxic water from the deeper anoxic water. Nitrate levels were lower in the anoxic water and declined rapidly with depth. The significant association ( r = - 0.91) between increasing δ 15N values and decreasing nitrate concentrations indicated that the nitrate was denitrified. High chloride concentrations in the anoxic zone beneath the retarding layer are thought to originate from the sludge storage lagoon and/or the sludge compost piles. Tritium and atrazine levels confirm that this is recent recharge water. Denitrification has utilized most of the original nitrate and DOC in the plume.

  19. Removal of Nitrate From Aqueous Solution Using Rice Chaff

    Directory of Open Access Journals (Sweden)

    Dehghani

    2015-09-01

    Full Text Available Background Nitrate is largely dissolved in the surface and ground water, due to its high solubility. Continual uptake of nitrite through drinking water can lead to problems and diseases (such as blue baby for humans, especially children. Objectives The aim of this study was to develop a new and inexpensive method for the removal of nitrate from water. In this regard, the possibility of using chaff for removal of nitrate from aqueous solutions was studied and the optimum operating conditions of nitrate removal was determined. Materials and Methods This is a cross-sectional study conducted in laboratory scale. The UV spectrophotometer at a wavelength of maximum absorbance (220 nm was used to determine the nitrate concentration. The effect of pH, amount of chaff, temperature, and contact time were investigated. Results The result of this study revealed that chaff as an absorbent could remove nitrate from solutions, and the efficiency of adsorption increased as contact time increased from 5 to 30 minutes, amount of chaff increased from 1 to 3 g, temperature increased in a range of 300 - 400°C and the amount of pH decreased from 10 to 3. The maximum adsorption rate was around pH 3 (53.14%. Conclusions It was shown that the removal efficiency of nitrate was directly proportional to the amount of chaff, temperature, and contact time but inversely to the pH. This study showed that nitrate removal by chaff is a promising technique.

  20. Nitrate decontamination through functionalized chitosan in brackish water.

    Science.gov (United States)

    Appunni, Sowmya; Rajesh, Mathur P; Prabhakar, Sivaraman

    2016-08-20

    N, N, N-Triethyl ammonium functionalized cross-linked chitosan beads (TEACCB) was prepared by alkylation of glutaraldehyde cross-linked chitosan beads to remove nitrate from brackish water. Physico-chemical characteristics of TEACCB were analyzed using FTIR, SEM, EDAX, TGA, DTA, BET surface area, swelling ratio and pHzpc. The maximum nitrate removal capacity of TEACCB was 2.26meq/g and is higher than other reported chitosan based adsorbents. Nitrate removal ratio in the presence and absence of common anions like chloride and sulphate demonstrated the selectively of TEACCB towards nitrate. The kinetic data of nitrate removal fitted well with the pseudo-second-order kinetic model. The thermodynamic parameters indicated that nitrate removal could be spontaneous and exothermic in nature. TEACCB was reused with 100% efficiency after regenerating with 0.05N HCl. Column study was carried out to remove nitrate from brackish water. These results are very significant to develop TEACCB based nitrate removal technology with great efficiency. PMID:27178960

  1. Nitration of the tyrosine residues of porcine pancreatic colipase with tetranitromethane, and properties of the nitrated derivatives.

    Science.gov (United States)

    De Caro, J D; Behnke, W D; Bonicel, J J; Desnuelle, P A; Rovery, M

    1983-09-28

    The nitration of the long form (N-terminal valine) of porcine pancreatic colipase with tetranitromethane was investigated under a variety of conditions. Fractionation of the nitrated monomers on DE-cellulose led to well-defined derivatives containing one, two and three nitrotyrosines per mol. Automated Edman degradation of the nitrated peptides, especially that of the staphylococcal proteinase peptide (49-64) showed that Tyr-54 was nitrated very fast under all conditions. This residue was the only one to be nitrated in water. Partial nitration of Tyr-59 was induced by bile salt micelles, while both Tyr-59 and Tyr-58 reacted extensively in the presence of lysophosphatidylcholine micelles (in which tetranitromethane is concentrated 150-fold compared to water) or of a liquid tetranitromethane-water interface. The strong negative Cotton effect at 410 nm which has already been observed using unfractionated preparations of nitrated colipase (Behnke W.D. (1982) Biochim. Biophys. Acta 708, 118-123) is linked with the nitration of Tyr-59 and it is markedly reduced by taurodeoxycholate micelles, suggesting a conformational change induced by the micelles in the tyrosine region. Moreover, the pKa of the nitrotyrosine residues in nitrated colipase is the same as that of free nitrotyrosine (pKa = 6.8) and it is shifted to 7.6 in the presence of taurodeoxycholate micelles. Micelles protected colipase against polymerization during nitration. These data suggest that Tyr-58 and Tyr-59 are part of the interface recognition site of colipase. The participation of Tyr-55 in binding is not excluded. The upwards nitrotyrosine pKa shift in the colipase micelle complex may explain why nitrated colipase can reactivate lipase in a triacylglycerol-taurodeoxycholate system at pH 7.5. PMID:6615844

  2. A blood circulation model for reference man

    Energy Technology Data Exchange (ETDEWEB)

    Leggett, R.W.; Eckerman, K.F. [Oak Ridge National Lab., TN (United States). Health Sciences Research Div.; Williams, L.R. [Indiana Univ., South Bend, IN (United States). Div. of Liberal Arts and Sciences

    1999-01-01

    This paper describes a dynamic blood circulation model that predicts the movement and gradual dispersal of a bolus of material in the circulation after its intravascular injection into an adult human. The main purpose of the model is to improve the dosimetry of internally deposited radionuclides that decay in the circulation to a significant extent. The total blood volume is partitioned into the blood contents of 24 separate organs or tissues, right heart chambers, left heart chambers, pulmonary circulation, arterial outflow to the systemic tissues (aorta and large arteries), and venous return from the systemic tissues (large veins). As a compromise between physical reality and computational simplicity, the circulation of blood is viewed as a system of first-order transfers between blood pools, with the delay time depending on the mean transit time across the pool. The model allows consideration of incomplete, tissue-dependent extraction of material during passage through the circulation and return of material from tissues to plasma.

  3. Circulation of Venus upper mesosphere.

    Science.gov (United States)

    Zasova, Ludmila; Gorinov, Dmitry; Shakun, Alexey; Altieri, Francesca; Migliorini, Alessandra; Piccioni, Giuseppe; Drossart, Pierre

    2014-05-01

    Observation of the O2 1.27 μm airglow intensity distribution on the night side of Venus is one of the methods of study of the circulation in upper mesosphere 90-100 km. VIRTIS-M on board Venus Express made these observations in nadir and limb modes in Southern and Northern hemispheres respectively. Global map of the O2 night glow is published (Piccioni et al. 2009). In this work we use for analysis only data, obtained with exposure > 3 s to avoid high noisy data. It was found that intensity of emission decreases to poles and to terminators (similar to Piccioni et al.2009) in both hemispheres, which gives evidence for existence of SS-AS circulation with transport of the air masses through poles and terminators with ascending/descending flows at SS/AS areas. However, asymmetry of distribution of intensity of airglow is observed in both hemispheres. Global map for southern hemisphere (from nadir data) has good statistics at φ > 10-20° S and pretty poor at low latitude. Maximum emission is shifted from midnight by 1 - 2 hours to the evening (22-23h) and deep minimum of emission is found at LT=2-4 h at φ > 20° S. This asymmetry is extended up to equatorial region, however statistic is poor there. No evident indication for existence of the Retrograde Zonal Superrotation (RZS) is found: maximum emission in this case, which is resulting from downwards flow, should be shifted to the morning. The thermal tides, gravity waves are evidently influence on the night airglow distribution. VIRTIS limb observations cover the low northern latitudes and they are more sparse at higher latitudes. Intensity of airglow at φ = 0 - 20° N shows wide maximum, which is shifted by 1- 2 h from midnight to morning terminator. This obviously indicates that observed O2 night glow distribution in low North latitudes is explained by a superposition of SS-AS flow and RZS circulation at 95-100 km. This behavior is similar to the NO intensity distribution, obtained by SPICAV.

  4. Thermal Decomposition of Nitrated Tributyl Phosphate

    International Nuclear Information System (INIS)

    Contact between tributyl phosphate and aqueous solutions of nitric acid and/or heavy metal nitrate salts at elevated temperatures can lead to exothermic reactions of explosive violence. Even though such operations have been routinely performed safely for decades as an intrinsic part of the Purex separation processes, several so-called ''red oil'' explosions are known to have occurred in the United States, Canada, and the former Soviet Union. The most recent red oil explosion occurred at the Tomsk-7 separations facility in Siberia, in April 1993. That explosion destroyed part of the unreinforced masonry walls of the canyon-type building in which the process was housed, and allowed the release of a significant quantity of radioactive material

  5. Removal of gadolinium nitrate from heavy water

    Energy Technology Data Exchange (ETDEWEB)

    Wilde, E.W.

    2000-03-22

    Work was conducted to develop a cost-effective process to purify 181 55-gallon drums containing spent heavy water moderator (D2O) contaminated with high concentrations of gadolinium nitrate, a chemical used as a neutron poison during former nuclear reactor operations at the Savannah River Site (SRS). These drums also contain low level radioactive contamination, including tritium, which complicates treatment options. Presently, the drums of degraded moderator are being stored on site. It was suggested that a process utilizing biological mechanisms could potentially lower the total cost of heavy water purification by allowing the use of smaller equipment with less product loss and a reduction in the quantity of secondary waste materials produced by the current baseline process (ion exchange).

  6. Registration probability of alphas in cellulose nitrate

    International Nuclear Information System (INIS)

    Registration 'thresholds' of alpha particles in cellulose nitrate plastic present a statistical behaviour. The effect depends on etching conditions. It is particularly large in strong etching conditions, in which registration is transposed to high energies: up to 7.7 MeV for the conditions and energies studied. 'Registration probability' expresses more adequately the effect of registration constraints. The study of registration probability indicates that the 'target theory' can describe the effect. The parameters of target theory, m (number of targets) and D0 (the equivalent of biological dose D37) were found to be: m = 5 and D0 = 3 x 107 erg cm-3. Dose distribution around the trajectory of alphas of various energies is estimated. It is also deduced that track development takes place when the required dose for registration is deposited at a distance r >= 20 A from particle trajectory. (author)

  7. Electrolytic denitrification of alkaline nitrate and nitrite solution

    International Nuclear Information System (INIS)

    Processing of high-level waste at the Savannah River Plant (SRP) will produce a low-level alkaline salt solution, containing approximately 17% sodium nitrate and sodium nitrite. This solution will be incorporated into a cement wasteform, saltstone, and placed in an engineered landfill. Laboratory experiments have demonstrated the technical feasibility of electrochemically reducing the nitrate and nitrite in a synthetic, nonradioactive salt solution similar in composition to that expected to be produced at SRP. Greater than ninety-five percent of the sodium nitrate and sodium nitrite can be reduced electrolytically, producing ammonia, nitrogen, oxygen, and sodium hydroxide. Reduction of the nitrate and nitrite will reduce the leaching of nitrate and nitrite from the saltstone monolith. In addition, significant reductions in the volume of saltstone may be realized if the sodium hydroxide produced by electrolysis can be recycled

  8. Electrochemical processing of alkaline nitrate and nitrite solutions

    International Nuclear Information System (INIS)

    Processing of high-level waste at the Savannah River Plant (SRP) will produce, as a by product, a low- level, alkaline salt solution containing approximately 17% sodium nitrate and sodium nitrite. This solution will be incorporated into a cement formulation, saltstone, and placed in an engineered landfill. Electrochemical methods have been investigated to decrease the nitrate and nitrite in this solution in order to lower the leaching of nitrate and nitrite from saltstone and to reduce the volume of saltstone. Laboratory experiments have demonstrated the technical feasibility of electrolytically reducing the nitrate and nitrite in a synthetic salt solution similar in composition to that expected to be produced at SRP. Greater than 99% of the sodium nitrate and sodium nitrite can be reduced, producing ammonia, nitrogen, oxygen, and sodium hydroxide. In addition, significant reductions in the volume of saltstone may be realized if the sodium hydroxide produced by electrolysis can be recycled

  9. The effect of nitrate on ethylene biofiltration

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang-Hun, E-mail: lee323@alumni.purdue.edu [Department of Agricultural and Biological Engineering, Purdue University, 225 South University St., West Lafayette, 47907-2093 IN (United States); Li, Congna; Heber, Albert J. [Department of Agricultural and Biological Engineering, Purdue University, 225 South University St., West Lafayette, 47907-2093 IN (United States)

    2012-11-30

    Highlights: Black-Right-Pointing-Pointer Ethylene biofiltration strongly depends on nitrate concentrations and media types. Black-Right-Pointing-Pointer We examine reduced N supply can increase ethylene removals in biofilters. Black-Right-Pointing-Pointer Perlite medium is better for ethylene biofiltration than activated carbon medium. - Abstract: This study investigated the effects of filter media types and nitrate (NO{sub 3}{sup -}) concentrations in nutrient solutions on C{sub 2}H{sub 4} biofiltration. A new nutrient solution with zero NO{sub 3}{sup -} concentration was supplied to two perlite-bed biotrickling filters, two perlite-bed biofilters, and two GAC (Granular Activated Carbon)-bed biofilters, while the other with 2 g L{sup -1} of NO{sub 3}{sup -} was used for the other two GAC biofilters. All reactors underwent a total test duration of over 175 days with an EBRT (Empty Bed Residence Time) of 30 s, inlet gas flow rate of 7 L min{sup -1}, and inlet C{sub 2}H{sub 4} concentrations of 20-30 mg m{sup -3}. NO{sub 3}{sup -} concentration and media type significantly affected the C{sub 2}H{sub 4} removal efficiencies in all types of biofiltration. The perlite media with no NO{sub 3}{sup -} achieved C{sub 2}H{sub 4} removal efficiencies 10-50% higher than the others. A NO{sub 3}{sup -} concentration as high as 2 g L{sup -1} in the original nutrient solution may act as an inhibitor that suppresses the growth or activity of C{sub 2}H{sub 4} degraders. In addition, the perlite media resulted in higher C{sub 2}H{sub 4} removal efficiencies than GAC media, because the hydrophilic surface of the perlite leads to a higher moisture content and thus to favorable microbial growth.

  10. ARRAYS OF BOTTLES OF PLUTONIUM NITRATE SOLUTION

    Energy Technology Data Exchange (ETDEWEB)

    Margaret A. Marshall

    2012-09-01

    In October and November of 1981 thirteen approaches-to-critical were performed on a remote split table machine (RSTM) in the Critical Mass Laboratory of Pacific Northwest Laboratory (PNL) in Richland, Washington using planar arrays of polyethylene bottles filled with plutonium (Pu) nitrate solution. Arrays of up to sixteen bottles were used to measure the critical number of bottles and critical array spacing with a tight fitting Plexiglas® reflector on all sides of the arrays except the top. Some experiments used Plexiglas shells fitted around each bottles to determine the effect of moderation on criticality. Each bottle contained approximately 2.4 L of Pu(NO3)4 solution with a Pu content of 105 g Pu/L and a free acid molarity H+ of 5.1. The plutonium was of low 240Pu (2.9 wt.%) content. These experiments were sponsored by Rockwell Hanford Operations because of the lack of experimental data on the criticality of arrays of bottles of Pu solution such as might be found in storage and handling at the Purex Facility at Hanford. The results of these experiments were used “to provide benchmark data to validate calculational codes used in criticality safety assessments of [the] plant configurations” (Ref. 1). Data for this evaluation were collected from the published report (Ref. 1), the approach to critical logbook, the experimenter’s logbook, and communication with the primary experimenter, B. Michael Durst. Of the 13 experiments preformed 10 were evaluated. One of the experiments was not evaluated because it had been thrown out by the experimenter, one was not evaluated because it was a repeat of another experiment and the third was not evaluated because it reported the critical number of bottles as being greater than 25. Seven of the thirteen evaluated experiments were determined to be acceptable benchmark experiments. A similar experiment using uranyl nitrate was benchmarked as U233-SOL-THERM-014.

  11. Linear thermal circulator based on Coriolis forces.

    Science.gov (United States)

    Li, Huanan; Kottos, Tsampikos

    2015-02-01

    We show that the presence of a Coriolis force in a rotating linear lattice imposes a nonreciprocal propagation of the phononic heat carriers. Using this effect we propose the concept of Coriolis linear thermal circulator which can control the circulation of a heat current. A simple model of three coupled harmonic masses on a rotating platform permits us to demonstrate giant circulating rectification effects for moderate values of the angular velocities of the platform.

  12. The Ten Relationships in Rural Land Circulation

    OpenAIRE

    Cai, Zhirong; Ren, Shuo; Zhang, Zhigang

    2009-01-01

    The ten relationships during land circulation are discussed. Among them, the relationship between peasant household and government indicates that government should only carry out its service and regulatory functions and farmers should be the main body of land circulation, because peasants usually have no discourse power during land circulation. In the relationship between land ownership and contracting management right, we mainly discuss the transfer of land contracting management right and p...

  13. Water rotational jump driven large amplitude molecular motions of nitrate ions in aqueous potassium nitrate solution

    CERN Document Server

    Banerjee, Puja; Bagchi, Biman

    2016-01-01

    Molecular dynamics simulations of aqueous potassium nitrate solution reveal a highly complex rotational dynamics of nitrate ions where, superimposed on the expected continuous Brownian motion, are large amplitude angular jumps that are coupled to and at least partly driven by similar large amplitude jump motions in water molecules which are associated with change in the hydrogen bonded water molecule. These jumps contribute significantly to rotational and translational motions of these ions. We explore the detailed mechanism of these correlated (or, coupled) jumps and introduce a new time correlation function to decompose the coupled orientational- jump dynamics of solvent and solute in the aqueous electrolytic solution. Time correlation function provides for the unequivocal determination of the time constant involved in orientational dynamics originating from making and breaking of hydrogen bonds. We discover two distinct mechanisms-both are coupled to density fluctuation but are of different types.

  14. Green and controllable metal-free nitrification and nitration of arylboronic acids

    Institute of Scientific and Technical Information of China (English)

    Shuai Wang; Chun Chun Shu; Tao Wang; Jian Yu; Guo Bing Yan

    2012-01-01

    A novel and green nitrating reagent has been developed for the nitrification and nitration of arylboronic acids,which can be controlled by the reaction conditions.The process provides an attractive alternative to the traditional nitration protocols.

  15. Effects of mineral dust on global atmospheric nitrate concentrations

    Science.gov (United States)

    Karydis, V. A.; Tsimpidi, A. P.; Pozzer, A.; Astitha, M.; Lelieveld, J.

    2016-02-01

    This study assesses the chemical composition and global aerosol load of the major inorganic aerosol components, focusing on mineral dust and aerosol nitrate. The mineral dust aerosol components (i.e., Ca2+, Mg2+, K+, Na+) and their emissions are included in the ECHAM5/MESSy Atmospheric Chemistry model (EMAC). Gas/aerosol partitioning is simulated using the ISORROPIA-II thermodynamic equilibrium model that considers K+, Ca2+, Mg2+, NH4+, Na+, SO42-, NO3-, Cl-, and H2O aerosol components. Emissions of mineral dust are calculated online by taking into account the soil particle size distribution and chemical composition of different deserts worldwide. Presence of metallic ions can substantially affect the nitrate partitioning into the aerosol phase due to thermodynamic interactions. The model simulates highest fine aerosol nitrate concentration over urban and industrialized areas (1-3 µg m-3), while coarse aerosol nitrate is highest close to deserts (1-4 µg m-3). The influence of mineral dust on nitrate formation extends across southern Europe, western USA, and northeastern China. The tropospheric burden of aerosol nitrate increases by 44 % when considering interactions of nitrate with mineral dust. The calculated global average nitrate aerosol concentration near the surface increases by 36 %, while the coarse- and fine-mode concentrations of nitrate increase by 53 and 21 %, respectively. Other inorganic aerosol components are affected by reactive dust components as well (e.g., the tropospheric burden of chloride increases by 9 %, ammonium decreases by 41 %, and sulfate increases by 7 %). Sensitivity tests show that nitrate aerosol is most sensitive to the chemical composition of the emitted mineral dust, followed by the soil size distribution of dust particles, the magnitude of the mineral dust emissions, and the aerosol state assumption.

  16. The aerodynamics of circulation control

    Science.gov (United States)

    Wood, N. J.

    1981-01-01

    Two dimensional subsonic wind tunnel tests were conducted on a 20% thickness: chord ratio circulation controlled elliptic aerofoil section equipped with forward and reverse blowing slots. Overall performance measurements were made over a range of trailing edge blowing momentum coefficients from 0 to 0.04; some included the effect of leading edge blowing. A detailed investigation of the trailing edge wall jet, using split film probes, hot wire probes and total head tubes, provided measurements of mean velocity components, Reynolds normal and shear stresses, and radial static pressure. The closure of the two dimensional angular momentum and continuity equations was examined using the measured data, with and without correction, and the difficulty of obtaining a satisfactory solution illustrated. Suggestions regarding the nature of the flow field which should aid the understanding of Coanda effect and the theoretical solution of highly curved wall jet flows are presented.

  17. Irregular Labellings of Circulant Graphs

    OpenAIRE

    Anholcer, Marcin

    2011-01-01

    We investigate the \\textit{irregularity strength} ($s(G)$) and \\textit{total vertex irregularity strength} ($tvs(G)$) of circulant graphs $Ci_n(1,2,...,k)$ and prove that $tvs(Ci_n(1,2,...,k))=\\lceil\\frac{n+2k}{2k+1}\\rceil$, while $s(Ci_n(1,2,...,k))=\\lceil\\frac{n+2k-1}{2k}\\rceil$ except the case when $(n \\bmod 4k = 2k+1 \\wedge k\\bmod 2=1) \\vee n=2k+1$ and $s(Ci_n(1,2,...,k))=\\lceil\\frac{n+2k-1}{2k}\\rceil+1$.

  18. Inflammatory response and extracorporeal circulation.

    Science.gov (United States)

    Kraft, Florian; Schmidt, Christoph; Van Aken, Hugo; Zarbock, Alexander

    2015-06-01

    Patients undergoing cardiac surgery with extracorporeal circulation (EC) frequently develop a systemic inflammatory response syndrome. Surgical trauma, ischaemia-reperfusion injury, endotoxaemia and blood contact to nonendothelial circuit compounds promote the activation of coagulation pathways, complement factors and a cellular immune response. This review discusses the multiple pathways leading to endothelial cell activation, neutrophil recruitment and production of reactive oxygen species and nitric oxide. All these factors may induce cellular damage and subsequent organ injury. Multiple organ dysfunction after cardiac surgery with EC is associated with an increased morbidity and mortality. In addition to the pathogenesis of organ dysfunction after EC, this review deals with different therapeutic interventions aiming to alleviate the inflammatory response and consequently multiple organ dysfunction after cardiac surgery. PMID:26060024

  19. Role of Circulating Fibrocytes in Cardiac Fibrosis

    Institute of Scientific and Technical Information of China (English)

    Rong-Jie Lin; Zi-Zhuo Su; Shu-Min Liang; Yu-Yang Chen; Xiao-Rong Shu; Ru-Qiong Nie; Jing-Feng Wang

    2016-01-01

    Objective: It is revealed that circulating fibrocytes are elevated in patients/animals with cardiac fibrosis, and this review aims to provide an introduction to circulating fibrocytes and their role in cardiac fibrosis.Data Sources: This review is based on the data from 1994 to present obtained from PubMed.The search terms were "circulating fibrocytes" and "cardiac fibrosis".Study Selection: Articles and critical reviews, which are related to circulating fibrocytes and cardiac fibrosis, were selected.Results: Circulating fibrocytes, which are derived from hematopoietic stem cells, represent a subset of peripheral blood mononuclear cells exhibiting mixed morphological and molecular characteristics ofhematopoietic and mesenchymal cells (CD34+/CD45+/collagen I+).They can produce extracellular matrix and many cytokines.It is shown that circulating fibrocytes participate in many fibrotic diseases, including cardiac fibrosis.Evidence accumulated in recent years shows that aging individuals and patients with hypertension, heart failure, coronary heart disease, and atrial fibrillation have more circulating fibrocytes in peripheral blood and/or heart tissue, and this elevation of circulating fibrocytes is correlated with the degree of fibrosis in the hearts.Conclusions: Circulating fibrocytes are effector cells in cardiac fibrosis.

  20. The Rank of Integral Circulant Graphs

    Institute of Scientific and Technical Information of China (English)

    ZHOU Hou-qing

    2014-01-01

    A graph is called an integral graph if it has an integral spectrum i.e., all eigen-values are integers. A graph is called circulant graph if it is Cayley graph on the circulant group, i.e., its adjacency matrix is circulant. The rank of a graph is defined to be the rank of its adjacency matrix. This importance of the rank, due to applications in physics, chemistry and combinatorics. In this paper, using Ramanujan sums, we study the rank of integral circulant graphs and gave some simple computational formulas for the rank and provide an example which shows the formula is sharp.

  1. A brief etymology of the collateral circulation.

    Science.gov (United States)

    Faber, James E; Chilian, William M; Deindl, Elisabeth; van Royen, Niels; Simons, Michael

    2014-09-01

    It is well known that the protective capacity of the collateral circulation falls short in many individuals with ischemic disease of the heart, brain, and lower extremities. In the past 15 years, opportunities created by molecular and genetic tools, together with disappointing outcomes in many angiogenic trials, have led to a significant increase in the number of studies that focus on: understanding the basic biology of the collateral circulation; identifying the mechanisms that limit the collateral circulation's capacity in many individuals; devising methods to measure collateral extent, which has been found to vary widely among individuals; and developing treatments to increase collateral blood flow in obstructive disease. Unfortunately, accompanying this increase in reports has been a proliferation of vague terms used to describe the disposition and behavior of this unique circulation, as well as the increasing misuse of well-ensconced ones by new (and old) students of collateral circulation. With this in mind, we provide a brief glossary of readily understandable terms to denote the formation, adaptive growth, and maladaptive rarefaction of collateral circulation. We also propose terminology for several newly discovered processes that occur in the collateral circulation. Finally, we include terms used to describe vessels that are sometimes confused with collaterals, as well as terms describing processes active in the general arterial-venous circulation when ischemic conditions engage the collateral circulation. We hope this brief review will help unify the terminology used in collateral research.

  2. Improvement of Classification of Enterprise Circulating Funds

    Directory of Open Access Journals (Sweden)

    Rohanova Hanna O.

    2014-02-01

    Full Text Available The goal of the article lies in revelation of possibilities of increase of efficiency of managing enterprise circulating funds by means of improvement of their classification features. Having analysed approaches of many economists to classification of enterprise circulating funds, systemised and supplementing them, the article offers grouping classification features of enterprise circulating funds. In the result of the study the article offers an expanded classification of circulating funds, which clearly shows the role of circulating funds in managing enterprise finance and economy in general. The article supplements and groups classification features of enterprise circulating funds by: the organisation level, functioning character, sources of formation and their cost, and level of management efficiency. The article shows that the provided grouping of classification features of circulating funds allows exerting all-sided and purposeful influence upon indicators of efficiency of circulating funds functioning and facilitates their rational management in general. The prospect of further studies in this direction is identification of the level of attraction of loan resources by production enterprises for financing circulating funds.

  3. Circulating omentin concentration increases after weight loss

    Directory of Open Access Journals (Sweden)

    Ricart Wifredo

    2010-04-01

    Full Text Available Abstract Background Omentin-1 is a novel adipokine expressed in visceral adipose tissue and negatively associated with insulin resistance and obesity. We aimed to study the effects of weight loss-induced improved insulin sensitivity on circulating omentin concentrations. Methods Circulating omentin-1 (ELISA concentration in association with metabolic variables was measured in 35 obese subjects (18 men, 17 women before and after hypocaloric weight loss. Results Baseline circulating omentin-1 concentrations correlated negatively with BMI (r = -0.58, p Conclusion As previously described with adiponectin, circulating omentin-1 concentrations increase after weight loss-induced improvement of insulin sensitivity.

  4. Acute effect of nitric oxide supplement on blood nitrate/nitrite and hemodynamic variables in resistance trained men.

    Science.gov (United States)

    Bloomer, Richard J; Williams, Sara A; Canale, Robert E; Farney, Tyler M; Kabir, Mohammad M

    2010-10-01

    Nitric oxide dietary supplements are extremely popular within the sport and bodybuilding community. Most products contain l-arginine, for which there is no direct evidence that oral L-arginine increases circulating nitric oxide or blood flow. A new molecule (2-[nitrooxy]thyl 2-amino-3-methylbutanoate) is being marketed as a sport supplement for purposes of delivering "real nitric oxide" to the circulation. In the present study, we measured the acute effects of this supplement on blood nitrate/nitrite and hemodynamic variables. Ten resistance trained men (26 ± 4 years old; 8 ± 6 years of resistance exercise training) reported to the laboratory in random order after a 10-hour overnight fast on 2 occasions separated by 1 week and were provided the supplement (2-[nitrooxy]ethyl 2-amino-3-methylbutanoate) or placebo. Heart rate and blood pressure were recorded, and venous blood samples were collected before and at 5, 15, 30, and 60 minutes after complete breakdown of the supplement (5 minutes post intake) or placebo. Blood samples were assayed for plasma nitrate/nitrite. No interaction (p = 0.99), condition (p = 0.18), or time (p = 0.98) effects were noted for plasma nitrate/nitrite, with values remaining nearly identical across time for placebo (∼27 μmol·L(-1)) and increasing a maximum of ∼6.7% (from 32.9 to 35.1 μmol·L(-1)) at the 15-minute collection period for the supplement. In regards to hemodynamic variables, no interaction, condition, or time effects were noted for heart rate, systolic, or diastolic blood pressure (p > 0.05), with values near identical between conditions and virtually unchanged across time. These findings indicate that 2-(nitrooxy)ethyl 2-amino-3-methylbutanoate has a small effect on increasing circulating nitrate/nitrite and does not cause any change in hemodynamic variables within the 1 hour postingestion period in a sample of resistance trained men.

  5. Effects of Amino Acids Replacing Nitrate on Growth, Nitrate Accumulation, and Macroelement Concentrations in Pak-choi (Brassica chinensis L.)

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A hydroponic experiment was carried out to determine the influence of replacing 20% of nitrate-N in nutrient solutions with 20 individual amino acids on growth, nitrate accumulation, and concentrations of nitrogen (N), phosphorus (P), and potassium (K) in pak-choi (Brassica chinensis L.) shoots. When 20% of nitrate-N was replaced with arginine (Arg)compared to the full nitrate treatment, pak-choi shoot fresh and dry weights increased significantly (P ≤ 0.05), but when 20% of nitrate-N was replaced with alanine (Ala), valine (Val), leucine (Leu), isoleucine (Ile), proline (Pro), phenylalanine (Phe), methionine (Met), aspartic acid (Asp), glutamic acid (Glu), lysine (Lys), glycine (Gly), serine (Ser), threonine(Thr), cysteine (Cys), and tyrosine (Tyr), shoot fresh and dry weights decreased significantly (P ≤ 0.05). After replacing 20% of nitrate-N with asparagine (Asn) and glutamine (Gln), shoot fresh and dry weights were unaffected. Compared to the full nitrate treatment, amino acid replacement treatments, except for Cys, Gly, histidine (His), and Arg, significantly reduced (P ≤ 0.05) nitrate concentrations in plant shoots. Except for Cys, Leu, Pro, and Met, total N concentrations in plant tissues of the other amino acid treatments significantly increased (P ≤ 0.05). Amino acids also affected total P and K concentrations, but the effects differed depending on individual amino acids. To improve pak-choi shoot quality, Gln and Asn, due to their insignificant effects on pak-choi growth, their significant reduction in nitrate concentrations, and their increase in macroelement content in plants, may be used to partially replace nitrate-N.

  6. Nitrate contamination of groundwater: A conceptual management framework

    International Nuclear Information System (INIS)

    In many countries, public concern over the deterioration of groundwater quality from nitrate contamination has grown significantly in recent years. This concern has focused increasingly on anthropogenic sources as the potential cause of the problem. Evidence indicates that the nitrate (NO3) levels routinely exceed the maximum contaminant level (MCL) of 10 mg/l NO3-N in many aquifer systems that underlie agriculture-dominated watersheds. Degradation of groundwater quality due to nitrate pollution along with the increasing demand for potable water has motivated the adoption of restoration actions of the contaminated aquifers. Restoration efforts have intensified the dire need for developing protection alternatives and management options such that the ultimate nitrate concentrations at the critical receptors are below the MCL. This paper presents a general conceptual framework for the management of groundwater contamination from nitrate. The management framework utilizes models of nitrate fate and transport in the unsaturated and saturated zones to simulate nitrate concentration at the critical receptors. To study the impact of different management options considering both environmental and economic aspects, the proposed framework incorporates a component of a multi-criteria decision analysis. To enhance spatiality in model development along with the management options, the utilization of a land use map is depicted for the allocation and computation of on-ground nitrogen loadings from the different sources

  7. Isoprene nitrates: preparation, separation, identification, yields, and atmospheric chemistry

    Directory of Open Access Journals (Sweden)

    A. L. Lockwood

    2010-07-01

    Full Text Available Isoprene is an important atmospheric volatile organic compound involved in ozone production and NOx (NO+NO2 sequestration and transport. Isoprene reaction with OH in the presence of NO can form either isoprene hydroxy nitrates ("isoprene nitrates" or convert NO to NO2 which can photolyze to form ozone. While it has been shown that isoprene nitrate production can represent an important sink for NOx in forest impacted environments, there is little experimental knowledge of the relative importance of the individual isoprene nitrate isomers, each of which has a different fate and reactivity. In this work, we have identified the 8 individual isomers and determined their total and individual production yields. The overall yield of isoprene nitrates at atmospheric pressure and 295 K was found to be 0.070(+0.025/−0.015. Three isomers, representing nitrates resulting from OH addition to a terminal carbon, represent 90% of the total IN yield. We also determined the ozone rate constants for three of the isomers, and have calculated their atmospheric lifetimes, which range from ~1–2 h, making their oxidation products likely more important as atmospheric organic nitrates and sinks for nitrogen.

  8. Implementation of the eu nitrates directive in Turkey

    Directory of Open Access Journals (Sweden)

    Hatice BİLGİN YILDIRIM

    2012-06-01

    Full Text Available The EU Nitrates Directive is of a prime importance in respect of sustaining the natural resources for the reduction and prevention of nitrate pollution resulting from agricultural activities, and it constitutes an integral part of the EU Water Framework Directive. Accepted by the European Council in 1991, the directive entered into force being published in Official Gazette in 2004 in Turkey as “Regulation on the Protection of Waters against Pollution Caused by Nitrates from Agricultural Sources.” As of this date, works on harmonization have been intensely continued. The works brought together multiple organizations that are notable in terms of waterworks and ensured informatory exchange through the contributions of the EU member states. Approaching to the finalization of its harmonization process, Turkey will proclaim its country either a “border to border nitrate-sensitive zone” or “nitrate vulnerable zone” in order to issue the secondary legislations required by the Nitrates Directive in accordance with these approaches. This paper covers the current works conducted with regard to the implementation of the Nitrates Directive and it has been prepared aiming at inviting attentions to the current and possible complications in the implementation process.

  9. Waste generation reduction: nitrates. FY 1984 status report

    International Nuclear Information System (INIS)

    A study was initiated at Rocky Flats Plant (RFP) to develop and demonstrate technology to eliminate nitrates in low-level waste streams without generating objectionable oxides of nitrogen. Various chemical and thermal methods of denitrification were investigated earlier in this program. Work in FY 1984 was conducted on the Thagard High Temperature Fluid Wall Reactor (HTFWR) and on an aqueous two-step process. Preliminary tests were conducted on a plasma torch system. Testing was completed with actual RFP nitrate wastes on an aqueous process consisting of formic and sulfuric acid reflux, followed by evaporation of the liquid to dryness. Results from this process show promising nitrate destruction, but with production of some NO/sub x/ in the off-gas. Also completed in aqueous testing were laser excitation techniques, indicating that the high activation energy of the nitrate ion can be overcome with a simpler chemical reaction with additional energy applied. Experiments were conducted using an HTFWR to determine its nitrate/nitrite destruction efficiency on simulated RFP and Savannah River Plant waste streams. These streams included nitrate-contaminated soils and feeds containing surrogate fission products. Various additives were tested to enhance nitrate destruction, reduce NO/sub x/ off-gas generation, and produce an acceptable final waste form

  10. Agricultural Impact on Groundwater Vulnerability to Nitrate in Northern Croatia

    Directory of Open Access Journals (Sweden)

    Marina Bubalo

    2014-05-01

    Full Text Available There is noticeable negative impact on soil and water quality caused by nutrient leaching, especially nitrate. Five regions in Croatia are preliminary delineated as nitrate vulnerable zones, including potentially vulnerable zones (PVZ and vulnerable zones (VZ, one of them being Varaždin County. Agricultural land spreads on 59% of its total area. The survey was carried out to analyze two available land use databases, ARKOD and CLC 2006, to determine relation between land use and vulnerability to nitrate. Results of on-going groundwater, soil and percolate research (nitrate concentrations in the same area are used for more precise nitrate vulnerability determination. Database analysis revealed no significant difference in land use within VZ and PVZ. Groundwater monitoring shows no consistency between nitrate concentrations and PVZ/VZ designation. Furthermore, the difference in the amount of residual soil nitrogen in two years of research was determined. Results of lysimeter study show that up to 32% of applied nitrogen is percolated to deeper soil layers indicating high agricultural impact on groundwater vulnerability to nitrate.

  11. Agricultural Impact on Groundwater Vulnerability to Nitrate in Northern Croatia

    Directory of Open Access Journals (Sweden)

    Marina Bubalo

    2014-03-01

    Full Text Available There is noticeable negative impact on soil and water quality caused by nutrient leaching, especially nitrate. Five regions in Croatia are preliminary delineated as nitrate vulnerable zones, including potentially vulnerable zones (PVZ and vulnerable zones (VZ, one of them being Varaždin County. Agricultural land spreads on 59% of its total area. The survey was carried out to analyze two available land use databases, ARKOD and CLC 2006, to determine relation between land use and vulnerability to nitrate. Results of on-going groundwater, soil and percolate research (nitrate concentrations in the same area are used for more precise nitrate vulnerability determination. Database analysis revealed no significant difference in land use within VZ and PVZ. Groundwater monitoring shows no consistency between nitrate concentrations and PVZ/VZ designation. Furthermore, the difference in the amount of residual soil nitrogen in two years of research was determined. Results of lysimeter study show that up to 32% of applied nitrogen is percolated to deeper soil layers indicating high agricultural impact on groundwater vulnerability to nitrate.

  12. NITRATE AND NITRITE CONCENTRATION IN VEGETABLES GRAWING AROUND ISFAHAN CITY

    Directory of Open Access Journals (Sweden)

    R.A JAFARI

    2001-06-01

    Full Text Available Introduction: The improper and excess use of chemical fertilizers by the farmers special in "urea" form may cause the commulation of nitrates and nitrites in vegetables and fruits. This investigation has been done to determine the concentration of nitrates and nitrites in some vegetables growing around Isfahan. Methods: One hundred and thirteen random samples from 15 different kinds of green lest tuber vegetables were measured by Cadmium Column Procedure for nitrates and nitrites. Results: The mean of the nitrates level in green leaf and tuber-vegetables was 287.9 and 76.3 mg/kg, respectively. These amounts were more higher than standard value (67 mg/kg in the basis of wet material, significantly. The mean of the nitrite level in green leaf and tuber vegetables were 1.7 and 1 mg/kg, repectively, which were more higher than standard value (zero mg/kg in the basis of wet matrial. The most high concentration of nitrites and nitrates was seen in commondill and leek, repectively. Discussion: Amounts of nitrites and nitrates in our analysed samples exceeded the perimissible limits. The comulation of nitrates in some of the vegetables depend on the application of chemical fertilizers, temprature and wether, but the nitrites in vegetables is unusual in normal condition and the unsuitable storage of them causes it"s expansion.

  13. Kelvin's Canonical Circulation Theorem in Hall Magnetohydrodynamics

    CERN Document Server

    Shivamoggi, B K

    2016-01-01

    The purpose of this paper is to show that, thanks to the restoration of the legitimate connection between the current density and the plasma flow velocity in Hall magnetohydrodynamics (MHD), Kelvin's Circulation Theorem becomes valid in Hall MHD. The ion-flow velocity in the usual circulation integral is now replaced by the canonical ion-flow velocity.

  14. On So's conjecture for integral circulant graphs

    Directory of Open Access Journals (Sweden)

    J.W. Sander

    2015-04-01

    According to a conjecture of {\\sc So} two integral circulant graphs are isomorphic if and only if they are isospectral, i.e. they have the same eigenvalues (counted with multiplicities. We prove a weaker form of this conjecture, namely, that two integral circulant graphs with multiplicative divisor sets are isomorphic if and only if their spectral vectors coincide.

  15. Electrolytic Removal of Nitrate From CELSS Crop Residues

    Science.gov (United States)

    Colon, Guillermo; Sager, John

    1996-01-01

    The controlled ecological life support system (CELSS) resource recovery system is a waste processing system using aerobic and anaerobic bioreactors to recover plant nutrients and secondary foods from inedible biomass. Crop residues contain significant amounts of nitrate which presents two problems: (1) both CELSS biomass production and resource recovery consume large quantities of nitric acid, (2) nitrate causes a variety of problems in both aerobic and anaerobic bioreactors. A technique was proposed to remove the nitrate from potato inedible biomass leachate and to satisfy the nitric acid demand using a four compartment electrolytic cell.

  16. Effect of Ammonium Nitrate on Nanoparticle Size Reduction

    Directory of Open Access Journals (Sweden)

    Kalyana C. Pingali

    2008-01-01

    Full Text Available Ammonium nitrate was added to the spraying solution as a foaming agent to reduce the particle size of nanoparticles synthesized in the spray-pyrolysis process. Ammonium nitrate was effective in breaking the aerosol droplet size and generating nanoparticles that were of approximately one order-of-magnitude (from 200 to 20 nm smaller diameter than those created in the absence of ammonium nitrate in the feed solution. This technique makes it possible to control the particle diameter of metallic nanoparticles below 20 nm.

  17. Numerical Modeling of Ocean Circulation

    Science.gov (United States)

    Miller, Robert N.

    2007-01-01

    The modelling of ocean circulation is important not only for its own sake, but also in terms of the prediction of weather patterns and the effects of climate change. This book introduces the basic computational techniques necessary for all models of the ocean and atmosphere, and the conditions they must satisfy. It describes the workings of ocean models, the problems that must be solved in their construction, and how to evaluate computational results. Major emphasis is placed on examining ocean models critically, and determining what they do well and what they do poorly. Numerical analysis is introduced as needed, and exercises are included to illustrate major points. Developed from notes for a course taught in physical oceanography at the College of Oceanic and Atmospheric Sciences at Oregon State University, this book is ideal for graduate students of oceanography, geophysics, climatology and atmospheric science, and researchers in oceanography and atmospheric science. Features examples and critical examination of ocean modelling and results Demonstrates the strengths and weaknesses of different approaches Includes exercises to illustrate major points and supplement mathematical and physical details

  18. Inorganic nitrate promotes the browning of white adipose tissue through the nitrate-nitrite-nitric oxide pathway.

    Science.gov (United States)

    Roberts, Lee D; Ashmore, Tom; Kotwica, Aleksandra O; Murfitt, Steven A; Fernandez, Bernadette O; Feelisch, Martin; Murray, Andrew J; Griffin, Julian L

    2015-02-01

    Inorganic nitrate was once considered an oxidation end product of nitric oxide metabolism with little biological activity. However, recent studies have demonstrated that dietary nitrate can modulate mitochondrial function in man and is effective in reversing features of the metabolic syndrome in mice. Using a combined histological, metabolomics, and transcriptional and protein analysis approach, we mechanistically defined that nitrate not only increases the expression of thermogenic genes in brown adipose tissue but also induces the expression of brown adipocyte-specific genes and proteins in white adipose tissue, substantially increasing oxygen consumption and fatty acid β-oxidation in adipocytes. Nitrate induces these phenotypic changes through a mechanism distinct from known physiological small molecule activators of browning, the recently identified nitrate-nitrite-nitric oxide pathway. The nitrate-induced browning effect was enhanced in hypoxia, a serious comorbidity affecting white adipose tissue in obese individuals, and corrected impaired brown adipocyte-specific gene expression in white adipose tissue in a murine model of obesity. Because resulting beige/brite cells exhibit antiobesity and antidiabetic effects, nitrate may be an effective means of inducing the browning response in adipose tissue to treat the metabolic syndrome.

  19. The effect of peroxynitrite decomposition catalyst MnTBAP on aldehyde dehydrogenase-2 nitration by organic nitrates: role in nitrate tolerance.

    Science.gov (United States)

    Mollace, Vincenzo; Muscoli, Carolina; Dagostino, Concetta; Giancotti, Luigino Antonio; Gliozzi, Micaela; Sacco, Iolanda; Visalli, Valeria; Gratteri, Santo; Palma, Ernesto; Malara, Natalia; Musolino, Vincenzo; Carresi, Cristina; Muscoli, Saverio; Vitale, Cristiana; Salvemini, Daniela; Romeo, Francesco

    2014-11-01

    Bioconversion of glyceryl trinitrate (GTN) into nitric oxide (NO) by aldehyde dehydrogenase-2 (ALDH-2) is a crucial mechanism which drives vasodilatory and antiplatelet effect of organic nitrates in vitro and in vivo. Oxidative stress generated by overproduction of free radical species, mostly superoxide anions and NO-derived peroxynitrite, has been suggested to play a pivotal role in the development of nitrate tolerance, though the mechanism still remains unclear. Here we studied the free radical-dependent impairment of ALDH-2 in platelets as well as vascular tissues undergoing organic nitrate ester tolerance and potential benefit when using the selective peroxynitrite decomposition catalyst Mn(III) tetrakis (4-Benzoic acid) porphyrin (MnTBAP). Washed human platelets were made tolerant to nitrates via incubation with GTN for 4h. This was expressed by attenuation of platelet aggregation induced by thrombin (40U/mL), an effect accompanied by GTN-related induction of cGMP levels in platelets undergoing thrombin-induced aggregation. Both effects were associated to attenuated GTN-induced nitrite formation in platelets supernatants and to prominent nitration of ALDH-2, the GTN to NO metabolizing enzyme, suggesting that GTN tolerance was associated to reduced NO formation via impairment of ALDH-2. These effects were all antagonized by co-incubation of platelets with MnTBAP, which restored GTN-induced responses in tolerant platelets. Comparable effect was found under in in vivo settings. Indeed, MnTBAP (10mg/kg, i.p.) significantly restored the hypotensive effect of bolus injection of GTN in rats made tolerants to organic nitrates via chronic administration of isosorbide-5-mononitrate (IS-5-MN), thus confirming the role of peroxynitrite overproduction in the development of tolerance to vascular responses induced by organic nitrates. In conclusion, oxidative stress subsequent to prolonged use of organic nitrates, which occurs via nitration of ALDH-2, represents a key event

  20. Thorium Nitrate Stockpile Drum Characterization Report

    International Nuclear Information System (INIS)

    Thorium nitrate (ThN) has been stored at depots for several decades and the Defense National Stockpile Center (DNSC) has evaluated options for its disposition. In support of this project, Oak Ridge National Laboratory (ORNL) has directed a characterization campaign for the ThN. The analytical results lead to the following conclusions: the ThN could be classified as LSA-1; the ThN does not contain hazardous contaminants at concentrations that would cause it to be categorized as a mixed waste if were declared to be a waste; the ThN is not required to be classfied as a Division 5.1 oxidizer per the US Dept. of Transportation definition; and, the disposal of the ThN would not be regulated by the Resource Conservation and Recovery Act and thus it could be accepted for disposal at the Nevada Test Site. This report disucsses the regulatory requirements involved with the packaging, transportation, and disposal of the ThN stockpile at the NTS. It also provides background information about the ThN stockpile, the current packaging configurations, and the current storage arrangements. The reader is also provided a description of the ThN and headspace gas sampling activities that wer conducted in 2002 and 2003 respectively. The basis for using ISO containers to transport and dispose of the ThN is discussed

  1. Ammonium nitrate: a promising rocket propellant oxidizer

    Science.gov (United States)

    Oommen; Jain

    1999-06-30

    Ammonium nitrate (AN) is extensively used in the area of fertilizers and explosives. It is present as the major component in most industrial explosives. Its use as an oxidizer in the area of propellants, however, is not as extensive as in explosive compositions or gas generators. With the growing demand for environmental friendly chlorine free propellants, many attempts have been made of late to investigate oxidizers producing innocuous combustion products. AN, unlike the widely used ammonium perchlorate, produces completely ecofriendly smokeless products. Besides, it is one of the cheapest and easily available compounds. However, its use in large rocket motors is restricted due to some of its adverse characteristics like hygroscopicity, near room temperature phase transformation involving a volume change, and low burning rate (BR) and energetics. The review is an attempt to consolidate the information available on the various issues pertaining to its use as a solid propellant oxidizer. Detailed discussions on the aspects relating to phase modifications, decomposition chemistry, and BR and energetics of AN-based propellants, are presented. To make the review more comprehensive brief descriptions of the history, manufacture, safety, physical and chemical properties and various other applications of the salt are also included. Copyright 1999 Elsevier Science B.V.

  2. Oxidative and nitrative stress in neurodegeneration.

    Science.gov (United States)

    Cobb, Catherine A; Cole, Marsha P

    2015-12-01

    Aerobes require oxygen for metabolism and normal free radical formation. As a result, maintaining the redox homeostasis is essential for brain cell survival due to their high metabolic energy requirement to sustain electrochemical gradients, neurotransmitter release, and membrane lipid stability. Further, brain antioxidant levels are limited compared to other organs and less able to compensate for reactive oxygen and nitrogen species (ROS/RNS) generation which contribute oxidative/nitrative stress (OS/NS). Antioxidant treatments such as vitamin E, minocycline, and resveratrol mediate neuroprotection by prolonging the incidence of or reversing OS and NS conditions. Redox imbalance occurs when the antioxidant capacity is overwhelmed, consequently leading to activation of alternate pathways that remain quiescent under normal conditions. If OS/NS fails to lead to adaptation, tissue damage and injury ensue, resulting in cell death and/or disease. The progression of OS/NS-mediated neurodegeneration along with contributions from microglial activation, dopamine metabolism, and diabetes comprise a detailed interconnected pathway. This review proposes a significant role for OS/NS and more specifically, lipid peroxidation (LPO) and other lipid modifications, by triggering microglial activation to elicit a neuroinflammatory state potentiated by diabetes or abnormal dopamine metabolism. Subsequently, sustained stress in the neuroinflammatory state overwhelms cellular defenses and prompts neurotoxicity resulting in the onset or amplification of brain damage. PMID:26024962

  3. Reaction of lanthanide nitrates with macrocyclic amidoacylhydrazones

    Energy Technology Data Exchange (ETDEWEB)

    Malinka, E.V.; Bondarev, M.L.; Bel' tyukova, S.V.; Poleuktov, N.S.; Nazarenko, N.A.

    1987-09-01

    This paper deals with a study of the reaction of neodymium and europium nitrates with 3,5,14,16-tetraazasubstituted dibenzo (d,j) (1,2,6,9,13,14) hexaazahexadeca-2,4,10,12-tetraene-7,8,15,16-tetraones. The authors carried out the investigations by means of conductimetry, UV luminescence, IR spectroscopy, and mass spectroscopy. Conductimetric titrations of the neodymium complexes were carried out on an OK-102/1 conductimeter. The luminescence spectra of the europium ion in the region of the /sup 5/D/sub 0/ ..-->.. /sup 7/F/sub 1/ and /sup 5/D/sub 0/ ..-->.. /sup 7/F/sub 2/ transitions (550-620 nm) were recorded on an ISP-51 spectrograph with an FEP-1 photoelectric attachment, using excitation by an SVD-120A mercury quartz lamp. The UV spectra of solutions of the compounds and the IR spectra of the solid substances in KBr disks were recorded on SpecordUViS and UR-20 spectrophotometers, respectively, and the mass spectra on a Varian Mat-112 spectrometer.

  4. Nitration of Polystyrene Part-I Effect of Molecular Weight of Polymer on Nitration

    Directory of Open Access Journals (Sweden)

    I. Bajaj

    1967-01-01

    Full Text Available Polystyrene in the molecular weight range, 3.67*10/Sup4 to 47.86*10/Sup10 has been nitrated in fuming nitric acid at 50 Degree C and degree of substitution of nitro group per monomeric unit in the polymer chains varying from 1.03 to 1.11 has been obtained. Molecular weight of the initial polymers have been found no appreciable effect on the degree of substitution. Degradation of the polymer chain is, however, found to be more pronounced in high molecular weight polymers.

  5. Deprotection of oximes using urea nitrate under microwave irradiation

    Indian Academy of Sciences (India)

    P T Perumal; M Anniyappan; D Muralidharan

    2004-08-01

    A new mild and efficient method for the cleavage of oximes to carbonyl compounds using readily available urea nitrate in acetonitrile-water (95 : 5), under microwave irradiation within 2 min, in good yields is reported.

  6. Thioploca spp: filamentous sulfur bacteria with nitrate vacuoles

    DEFF Research Database (Denmark)

    Jørgensen, BB; Gallardo, VA

    1999-01-01

    Thioploca spp. are multicellular, filamentous, colorless sulfur bacteria inhabiting freshwater and marine sediments. They have elemental sulfur inclusions similar to the phylogenetically closely related Beggiatoa, but in contrast to these they live in bundles surrounded by a common sheath. Vast...... communities of large Thioploca species live along the Pacific coast of South America and in other upwelling areas of high organic matter sedimentation with bottom waters poor in oxygen and rich in nitrate. Each cell of these thioplocas harbors a large liquid vacuole which is used as a storage for nitrate...... with a concentration of lip to 506 mM. The nitrate is used as an electron acceptor for sulfide oxidation and the bacteria may grow autotrophically or mixotrophically using acetate or other organic molecules as carbon source. The filaments stretch up into the overlying seawater, from which they take up nitrate...

  7. Dietary nitrate and nitrite: Benefits, risks, and evolving perceptions.

    Science.gov (United States)

    Bedale, Wendy; Sindelar, Jeffrey J; Milkowski, Andrew L

    2016-10-01

    Consumers have an illogical relationship with nitrite (and its precursor, nitrate) in food. Despite a long history of use, nitrite was nearly banned from use in foods in the 1970s due to health concerns related to the potential for carcinogenic nitrosamine formation. Changes in meat processing methods reduced those potential risks, and nitrite continued to be used in foods. Since then, two opposing movements continue to shape how consumers view dietary nitrate and nitrite. The discovery of the profound physiological importance of nitric oxide led to the realization that dietary nitrate contributes significantly to the nitrogen reservoir for nitric oxide formation. Numerous clinical studies have also demonstrated beneficial effects from dietary nitrate consumption, especially in vascular and metabolic health. However, the latest wave of consumer sentiment against food additives, the clean-label movement, has renewed consumer fear and avoidance of preservatives, including nitrite. Education is necessary but may not be sufficient to resolve this disconnect in consumer perception. PMID:26994928

  8. Nitrates in the human diet - good or bad?

    OpenAIRE

    Benjamin, Nigel

    2000-01-01

    Les nitrates dans l'alimentation humaine : une bonne ou une mauvaise chose ? Bien que les nitrates soient connus depuis des siècles, c'est seulement depuis peu qu'il a été découvert que les nitrates sont synthétisés chez les mammifères à partir du monoxyde d'azote, et que les nitrates formés ont la capacité de tuer les bactéries présentes dans les aliments consommés. Les mécanismes par lesquels le monoxyde d'azote et d'autres oxydes d'azote manifestent une toxicité sélective vis-à-vis de bact...

  9. Interannual variability of the Adriatic Sea circulation

    Science.gov (United States)

    Beg Paklar, Gordana; Sepic, Jadranka; Grbec, Branka; Dzoic, Tomislav; Kovac, Zarko; Ivatek-Sahdan, Stjepan

    2016-04-01

    The Regional Ocean Modeling System (ROMS) was implemented in order to reproduce interannual variability of the Adriatic Sea circulation. Simulations and model result analysis were performed for a three-year period from 1st January 2011 to 31st December 2013. ROMS model run was forced with realistic atmospheric fields obtained from meteorological model Aladin, climatological river discharges, tides and Mediterranean circulation imposed at the southern open boundary. Atmospheric forcing included momentum, heat and water fluxes calculated interactively from the Aladin surface fields during ROMS model simulations. Model results were compared with available CTD and ADCP measurements and discussed in the light of the climatological circulation and thermohaline properties of the Adriatic Sea and its coastal areas. Interannual variability in the Adriatic circulation is related to the prevailing atmospheric conditions, changes in the hydrological conditions and water mass exchange at the Otranto Strait. Basic features of the Adriatic circulation - basin-wide cyclonic circulation with several embedded smaller cyclonic gyres around main pits - are well reproduced by ROMS model. Modelled temperatures and salinities are within corresponding seasonal intervals, although measured profiles generally indicate stronger stratification than modelled ones. Summer circulation in 2011 with current reversal obtained along the eastern Adriatic coast was related to the sampling results of the early fish stages as well as to ARGO drifter movements. Simulated fields from the Adriatic scale model were used to prescribe the initial and open boundary conditions for the interannual simulation in the middle Adriatic coastal domain.

  10. Nitrate leaching from short-hydroperiod floodplain soils

    Directory of Open Access Journals (Sweden)

    B. Huber

    2012-05-01

    Full Text Available Numerous studies have shown the importance of riparian zones to reduce nitrate (NO3 contamination coming from adjacent agricultural land. Much less is known about nitrogen (N transformations and nitrate fluxes in riparian soils with short hydroperiods (1–3 days of inundation and there is no study that could show whether these soils are a N sink or source.

    Within a restored section of the Thur River in NE Switzerland, we measured nitrate concentrations in soil solutions as an indicator of the net nitrate production. Samples were collected along a quasi-successional gradient from frequently inundated gravel bars to an alluvial forest, at three different depths (10, 50 and 100 cm over a one-year period. Along this gradient we quantified N input (atmospheric deposition and sedimentation and N output (leaching to create a nitrogen balance and assess the risk of nitrate leaching from the unsaturated soil to the groundwater.

    Overall, the main factor explaining the differences in nitrate concentrations was the variability in soil texture and volumetric water content (VWC at field capacity (FC. In subsoils with high VWC at FC and VWC near 100 % FC, high nitrate concentrations were observed, often exceeding the Swiss and EU groundwater quality criterions of 400 and 800 μmol l−1, respectively. High sedimentation rates of river-derived nitrogen led to apparent N retention up to 200 kg N ha−1 yr−1 in the frequently inundated zones. By contrast, in the mature alluvial forest, nitrate leaching exceeded total N input most of the time. As a result of the large soil N pools, high amounts of nitrate were produced by nitrification and up to 94 kg N-NO3 ha−1 yr−1 were leached into the groundwater. Thus, during flooding when water fluxes are high, nitrate from soils can contribute up to 11 % to the total nitrate load in groundwater.

  11. Nitrate leaching from short-hydroperiod floodplain soils

    Directory of Open Access Journals (Sweden)

    B. Huber

    2012-11-01

    Full Text Available Numerous studies have shown the importance of riparian zones to reduce nitrate (NO3 contamination coming from adjacent agricultural land. Much less is known about nitrogen (N transformations and nitrate fluxes in riparian soils with short hydroperiods (1–3 days of inundation and there is no study that could show whether these soils are a N sink or source. Within a restored section of the Thur River in NE Switzerland, we measured nitrate concentrations in soil solutions as an indicator of the net nitrate production. Samples were collected along a quasi-successional gradient from frequently inundated gravel bars to an alluvial forest, at three different depths (10, 50 and 100 cm over a one-year period. Along this gradient we quantified N input (atmospheric deposition and sedimentation and N output (leaching to create a nitrogen balance and assess the risk of nitrate leaching from the unsaturated soil to the groundwater. Overall, the main factor explaining the differences in nitrate concentrations was the field capacity (FC. In subsoils with high FCs and VWC near FC, high nitrate concentrations were observed, often exceeding the Swiss and EU groundwater quality criterions of 400 and 800 μmol L−1, respectively. High sedimentation rates of river-derived nitrogen led to apparent N retention up to 200 kg N ha−1 yr−1 in the frequently inundated zones. By contrast, in the mature alluvial forest, nitrate leaching exceeded total N input most of the time. As a result of the large soil N pools, high amounts of nitrate were produced by nitrification and up to 94 kg N-NO3 ha−1 yr−1 were leached into the groundwater. Thus, during flooding when water fluxes are high, nitrate from soils can contribute up to 11% to the total nitrate load in groundwater.

  12. Multiparameter emergency-situation evaluation system for nitration processes

    Energy Technology Data Exchange (ETDEWEB)

    Sakhnenko, V.I.; Serov, Y.V.; Ulanov, V.N. [Technological Inst., St. Petersburg (Russian Federation)] [and others

    1992-08-10

    Nitration is widely used in making drugs, vitamins, dyes, perfumery components, corrosion inhibitors to be added to engine fuels, and additives for fuels to raise the cetane numbers. In nitration systems, emergency control measures may be based on majority-logic processing (two out of three), which improves the probability of fault-free operation in the protection system. The theoretical concepts are supported by experiments and calculations. 18 refs., 5 figs., 1 tab.

  13. REMEDIATION OF NITRATE-CONTAMINATED GROUNDWATER USING A BIOBARRIER

    Energy Technology Data Exchange (ETDEWEB)

    B. STRIETELMEIER; M. ESPINOSA

    2001-01-01

    A biobarrier system has been developed for use in remediating shallow alluvial groundwater. This barrier is made from highly porous materials that are relatively long-lasting, carbon-based (to supply a limiting nutrient in nitrate destruction, in most cases), extremely inexpensive, and easy to replace. In a series of laboratory studies, we have determined the effectiveness of this barrier at destroying nitrate and perchlorate in groundwater from Mortandad Canyon at Los Alamos National Laboratory (LANL). This groundwater was obtained from a monitoring well, MCO-5, which is located in the flowpath of the discharge waters from the LANL Radioactive Liquid Waste Treatment Facility (RLWTF). Water with elevated nitrate levels was discharged from this plant for many years. Recently, the nitrate levels have been brought under the discharge limits. However, the historical discharge has resulted in a nitrate plume in the alluvial groundwater in this canyon. The LANL Multi-Barrier project was initiated in 1999 to develop a system of barriers that would prevent the transport of radionuclides, metals, colloids and other contaminants, including nitrate and perchlorate, further down the canyon in order to protect populations down-gradient. The biobarrier will be part of this Multi-Barrier system. We have demonstrated the destruction of nitrate at levels up to 6.5-9.7 mM nitrate (400-600 mg/L), and that of perchlorate at levels of about 4.3 {micro}M perchlorate (350 ppb). We have quantified the populations of microorganisms present in the biofilm that develops on the biobarrier. The results of this research will be discussed along with other potential applications of this system.

  14. REMEDIATION OF NITRATE-CONTAMINATED GROUNDWATER USING A BIOBARRIER

    Energy Technology Data Exchange (ETDEWEB)

    B. STRIETELMEIR; ET AL

    2000-12-01

    A biobarrier system has been developed for use in remediating shallow alluvial groundwater. This barrier is made from highly porous materials that are relatively long-lasting, carbon-based (to supply a limiting nutrient in nitrate destruction, in most cases), and extremely inexpensive and easy to emplace. In a series of laboratory studies, we have determined the effectiveness of this barrier at destroying nitrate and perchlorate in groundwater from Mortandad Canyon at Los Alamos National Laboratory (LANL). This groundwater was obtained from a monitoring well, MCO-5, which is located in the flowpath of the discharge waters from the LANL Radioactive Liquid Waste Treatment Facility (RLWTF). Water with elevated nitrate levels has been discharged from this plant for many years, until recently when the nitrate levels have been brought under the discharge limits. However, the historical discharge has resulted in a nitrate plume in the alluvial groundwater in this canyon. The LANL Multi-Barrier project was initiated this past year to develop a system of barriers that would prevent the transport of radionuclides, metals, colloids and other contaminants, including nitrate and perchlorate, further down the canyon in order to protect populations down-gradient. The biobarrier. will be part of this Multi-Barrier system. We have demonstrated the destruction of nitrate at levels up to 6.5-9.7 mhl nitrate (400-600 mg/L), and that of perchlorate at levels of about 4.3 {micro}M perchlorate (350 ppb). We have quantified the populations of microorganisms present in the biofilm that develops on the biobarrier. The results of this research will be discussed along with other potential applications of this system.

  15. Determination of nitrate by anion exchange with ultraviolet detection

    Energy Technology Data Exchange (ETDEWEB)

    McComas, J.G.

    1976-01-01

    A weak base anion exchange resin is synthesized by surface bonding 3-aminopropyltriethoxysilane to silica gel. This silylated silica gel is used to separate nitrate from interferences. The nitrate is then determined by measuring its absorbance at 220 nm. An interference study was performed and no anions commonly found in potable water interferes. A comparison of this method was made with the brucine method on real samples and satisfactory agreement was obtained between the two methods.

  16. Low serum total nitrite and nitrate levels in severe leptospirosis

    OpenAIRE

    Kalugalage, Thilini; Rodrigo, Chaturaka; Vithanage, Thamal; Somaratne, Pranitha; de Silva, H. Janaka; Handunnetti, Shiroma; Rajapakse, Senaka

    2013-01-01

    Background The relationship between inducible nitric oxide synthatase activity and disease severity in leptospirosis is unclear. Nitric oxide is converted to nitrites and nitrates, thus nitrite and nitrate levels (NOx) in serum are considered surrogate markers for nitric oxide. NOx are excreted through the kidneys, and elimination is diminished in renal impairment. We assessed the correlation of NOx with disease severity in patients with leptospirosis, compared with healthy controls and non-l...

  17. Radiolysis studies of uranyl nitrate solution in nitric acid medium

    International Nuclear Information System (INIS)

    The radiolysis of acidic uranyl nitrate solutions was investigated using Co-60 gamma radiation. Hydrogen peroxide was determined as a function of increasing dose. The UV-vis absorption spectra of the irradiated solutions were measured and the spectral changes were analyzed. The increasing dose increases the absorbance intensities, possibly by an increment in nitrate concentration produced by radiolysis, which can originate the formation of different uranyl complexes in solution. (author)

  18. Occurrence of nitrate in Tanzanian groundwater aquifers: A review

    Science.gov (United States)

    Elisante, Eliapenda; Muzuka, Alfred N. N.

    2015-03-01

    More than 25 % of Tanzanian depends on groundwater as the main source of water for drinking, irrigation and industrial activities. The current trend of land use may lead to groundwater contamination and thus increasing risks associated with the usage of contaminated water. Nitrate is one of the contaminants resulting largely from anthropogenic activities that may find its way to the aquifers and thus threatening the quality of groundwater. Elevated levels of nitrate in groundwater may lead to human health and environmental problems. The current trend of land use in Tanzania associated with high population growth, poor sanitation facilities and fertilizer usage may lead to nitrate contamination of groundwater. This paper therefore aimed at providing an overview of to what extent human activities have altered the concentration of nitrate in groundwater aquifers in Tanzania. The concentration of nitrate in Tanzanian groundwater is variable with highest values observable in Dar es Salaam (up to 477.6 mg/l), Dodoma (up to 441.1 mg/l), Tanga (above 100 mg/l) and Manyara (180 mg/l). Such high values can be attributed to various human activities including onsite sanitation in urban centres and agricultural activities in rural areas. Furthermore, there are some signs of increasing concentration of nitrate in groundwater with time in some areas in response to increased human activities. However, reports on levels and trends of nitrate in groundwater in many regions of the country are lacking. For Tanzania to appropriately address the issue of groundwater contamination, a deliberate move to determine nitrate concentration in groundwater is required, as well as protection of recharge basins and improvement of onsite sanitation systems.

  19. Nitrates and Nitrites in the Treatment of Ischemic Cardiac Disease

    OpenAIRE

    Nossaman, Vaughn E.; Nossaman, Bobby D.; Kadowitz, Philip J.

    2010-01-01

    The organic nitrite, amyl of nitrite, was initially used as a therapeutic agent in the treatment of angina pectoris in 1867, but was replaced over a decade later by the organic nitrate, nitroglycerin (NTG), due to the ease of administration and longer duration of action. The administration of organic nitrate esters, such as NTG, continues to be used in the treatment of angina pectoris and heart failure during the birth of modern pharmacology. The clinical effectiveness is due to vasodilator a...

  20. Development of CO2 circulators

    International Nuclear Information System (INIS)

    The development of the basic machine types we have supplied has not been without problems. The Windscale AGR (the prototype AGR) was a small 1.2 MW vertically up circulator with an inlet temperature of 237 deg. C (459 deg. F). Oil leakage problems occurred and were cured in the works test facility and the machine went into service with no other problems. The Horizontal 5 MW machines for Hinkley/Hunterston were not so fortunate with vibration problems, interface corrosion problems (effecting the whole reactor) and material dimensional stability problems. Oil ingress problems did not show up in test work but were later reported from site. These reports were initially exagerated due to the measuring techniques which took the operators some time to resolve. In the vertical 5 MW machines for Hartlepool and Heysham 1 there are two interesting factors, firstly a spar failure and secondly shaft axial stability. Many of the problems were due to modifications at site or our inability to model all aspects of site installation from which lessons for the future can be learned. The latest stations Torness and Heysham II incorporate these lessons. The machines have been designed with so much margin that during the resolution of the reactor control rod gag problems the machines were run continuously at 20% overload (6.3 MW). From an initial accident case of 350 deg. C inlet temperature, this increased to 458 deg. C and now stands at 585 deg. C. No modifications to the impeller were required. The site experience to date is good with no operational problems reported. (author). 4 figs

  1. Circulating miRNA and cancer diagnosis

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    miRNAs are a class of small RNA molecules with regulatory function, and play an important role in tumor development and progression. It has been demonstrated that tumor-derived miRNAs exist in the circulating nucleic acids of cancer patients. This phenomenon implies that detection of the circulating miRNA may be an effective method for non-invasive diagnosis of cancer. In this review, we summarize the applications of the circulating miRNA as biomarkers in cancer diagnosis, as well as the latest research progress in this area.

  2. Natural Circulation Performance in Nuclear Power Plants

    International Nuclear Information System (INIS)

    The present paper deals with a study of natural circulation in PWR systems, The study consists of two parts: in the first one, natural circulation in experimental facilities simulating PWR plants was analyzed. This made it possible to gather a broad data base which was assumed as a reference for the subsequent part of the research. Seven Nuclear Power Plants nodalizations and additional experimental data from ''non-PWR'' facilities have been considered in the second part of the paper. Conclusions are drawn about natural circulation capabilities derived for the seven Nuclear Power Plants nodalizations and from data base pertinent to three ''non-PWR'' facilities. (author)

  3. Nitrate-transformations during simulated drought on a restored floodplain

    Science.gov (United States)

    Hoagland, B.; Russo, T. A.; Schmidt, C. M.; Tran, D.

    2015-12-01

    Water resources in the California Central Valley face challenges due to recurring drought, aging levee systems, and nitrate contamination. As decisions are made to restore floodplain connectivity, soil microbial metabolic pathways such as denitrification, anaerobic ammonium oxidation (anammox), and dissimilatory nitrate reduction to ammonium (DNRA) transform nitrate under saturated soil conditions and may each affect downstream water quality. However, few studies have quantified the contribution of all three pathways to nitrate retention in freshwater systems, and specifically in restored floodplains. Additionally, no former studies quantify the rates of these microbial nitrate transformations during floods after prolonged periods of drought. To test how flood duration impacts nitrogen cycling we added 15N-enriched tracer to soil mesocosms to measure denitrification, anammox, and DNRA transformation rates. In July 2015, we extracted seven soil mesocosms from the floodplain and riverbed of the Lower Cosumnes River in the San Joaquin Basin of California. Cosumnes River water enriched with 15N-NO3- tracer was pumped into each mesocosm at a constant rate simulating flood durations of 20 h, 30 h, and 96 h. Samples were collected from the surface water, soil pore water, drain water, and sediment for measurements of NO3-, NO2-, NH4+, gas isotopes, and DNA extraction. This study aims to demonstrate the relevance of anammox and DNRA to total nitrate retention and characterize the hydrologic conditions most favorable to each pathway.

  4. Effect of nitrate poisoning on some biochemical parameters in rats

    Directory of Open Access Journals (Sweden)

    M. B. Mahmood

    2011-01-01

    Full Text Available The present study was conducted to investigate the toxicity of potassium nitrate on glucose, cholesterol, alanine aminotransferase (ALT, aspartate aminotransferase (AST, and the possible ameliorative effect of ascorbic acid (Vitamin C. Male Wister rats are used as experimental model divided into three groups (each of 6-8 rats and treated for six weeks as follows: Group 1: served as control; Group 2: received 2 % potassium nitrate added to the forage and Group 3: received 2 % potassium nitrate together with 1 % ascorbic acid added to rat's forage. Nitrate treatment in group 2 leads to high significant increase levels of glucose in 3rd, 4th, and 5th weeks, cholesterol level increased significantly in both 4th and 5th weeks, while ALT levels increased in the 4th, 5th and 6th weeks, and AST increased significantly in the 5th and 6th weeks. Addition of ascorbic acid with potassium nitrate, lead to reverse all the parameters nearly to normal. It was concluded that potassium nitrate causes significant toxic effect on some biochemical parameters which was ameliorated by ascorbic acid.

  5. Bifunctional alkyl nitrates - trace constituents of the atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Kastler, J. [Department of Analytical and Environmental Chemistry, University of Ulm (Germany); Ballschmiter, K. [Center of Technology Assessment in Baden-Wuerttemberg, Stuttgart (Germany)

    1998-04-01

    Mono- and multifunctional esters of nitric acid (alkyl nitrates or organonitrates) form very complex mixtures of organic trace constituents in air. An analytical method was developed which combines selectivity in separation and detection in order to simplify this complexity in analytical terms. Mononitrates, dinitrates, keto nitrates, hydroxy nitrates of alkanes and alkenes, respecitvely, and bifunctional terpene nitrates were synthesized as reference substances. A specially developed new HPLC stationary phase (organonitrate phase) allows a group separation of mono-, di-, and hydroxy nitrates. After the HPLC preseparation the single components were finally separated by capillary HRGC-ECD and HRGC-MSD on polar and non-polar stationary phases. Mass spectrometric detection in the selected-ion-mode using the highly selective NO{sub 2}{sup +} fragment (m/z = 46 amu) led to very good selectivities for the nitric acid ester moiety. The analysis of a 100 m{sup 3} ambient air sample using this new analytical protocol allowed the identification of seven hydroxy nitrates and 24 dinitrates ranging from C2 to C7, 22 of them for the first time ever. (orig.) With 3 figs., 3 tabs., 20 refs.

  6. Denitrifying Bioreactors for Nitrate Removal: A Meta-Analysis.

    Science.gov (United States)

    Addy, Kelly; Gold, Arthur J; Christianson, Laura E; David, Mark B; Schipper, Louis A; Ratigan, Nicole A

    2016-05-01

    Meta-analysis approaches were used in this first quantitative synthesis of denitrifying woodchip bioreactors. Nitrate removal across environmental and design conditions was assessed from 26 published studies, representing 57 separate bioreactor units (i.e., walls, beds, and laboratory columns). Effect size calculations weighted the data based on variance and number of measurements for each bioreactor unit. Nitrate removal rates in bed and column studies were not significantly different, but both were significantly higher than wall studies. In denitrifying beds, wood source did not significantly affect nitrate removal rates. Nitrate removal (mass per volume) was significantly lower in beds with effects with bed temperature; a of 2.15 was quite similar to other studies. Lessons from this meta-analysis can be incorporated into bed designs, especially extending hydraulic retention times to increase nitrate removal under low temperature and high flow conditions. Additional column studies are warranted for comparative assessments, as are field-based studies for assessing in situ conditions, especially in aging beds, with careful collection and reporting of design and environmental data. Future assessment of these systems might take a holistic view, reviewing nitrate removal in conjunction with other processes, including greenhouse gas and other unfavorable by-product production. PMID:27136153

  7. Tidal pumping facilitates dissimilatory nitrate reduction in intertidal marshes

    Science.gov (United States)

    Zheng, Yanling; Hou, Lijun; Liu, Min; Liu, Zhanfei; Li, Xiaofei; Lin, Xianbiao; Yin, Guoyu; Gao, Juan; Yu, Chendi; Wang, Rong; Jiang, Xiaofen

    2016-02-01

    Intertidal marshes are alternately exposed and submerged due to periodic ebb and flood tides. The tidal cycle is important in controlling the biogeochemical processes of these ecosystems. Intertidal sediments are important hotspots of dissimilatory nitrate reduction and interacting nitrogen cycling microorganisms, but the effect of tides on dissimilatory nitrate reduction, including denitrification, anaerobic ammonium oxidation and dissimilatory nitrate reduction to ammonium, remains unexplored in these habitats. Here, we use isotope-tracing and molecular approaches simultaneously to show that both nitrate-reduction activities and associated functional bacterial abundances are enhanced at the sediment-tidal water interface and at the tide-induced groundwater fluctuating layer. This pattern suggests that tidal pumping may sustain dissimilatory nitrate reduction in intertidal zones. The tidal effect is supported further by nutrient profiles, fluctuations in nitrogen components over flood-ebb tidal cycles, and tidal simulation experiments. This study demonstrates the importance of tides in regulating the dynamics of dissimilatory nitrate-reducing pathways and thus provides new insights into the biogeochemical cycles of nitrogen and other elements in intertidal marshes.

  8. Groundwater head controls nitrate export from an agricultural lowland catchment

    Science.gov (United States)

    Musolff, Andreas; Schmidt, Christian; Rode, Michael; Lischeid, Gunnar; Weise, Stephan M.; Fleckenstein, Jan H.

    2016-10-01

    Solute concentration variability is of fundamental importance for the chemical and ecological state of streams. It is often closely related to discharge variability and can be characterized in terms of a solute export regime. Previous studies, especially in lowland catchments, report that nitrate is often exported with an accretion pattern of increasing concentrations with increasing discharge. Several modeling approaches exist to predict the export regime of solutes from the spatial relationship of discharge generating zones with solute availability in the catchment. For a small agriculturally managed lowland catchment in central Germany, we show that this relationship is controlled by the depth to groundwater table and its temporal dynamics. Principal component analysis of groundwater level time series from wells distributed throughout the catchment allowed derivation of a representative groundwater level time series that explained most of the discharge variability. Groundwater sampling revealed consistently decreasing nitrate concentrations with an increasing thickness of the unsaturated zone. The relationships of depth to groundwater table to discharge and to nitrate concentration were parameterized and integrated to successfully model catchment discharge and nitrate export on the basis of groundwater level variations alone. This study shows that intensive and uniform agricultural land use likely results in a clear and consistent concentration-depth relationship of nitrate, which can be utilized in simple approaches to predict stream nitrate export dynamics at the catchment scale.

  9. 77 FR 65532 - Solid Fertilizer Grade Ammonium Nitrate From the Russian Federation: Notice of Rescission of...

    Science.gov (United States)

    2012-10-29

    ... International Trade Administration Solid Fertilizer Grade Ammonium Nitrate From the Russian Federation: Notice... the antidumping duty order on solid fertilizer grade ammonium nitrate (ammonium nitrate) from the... Nitrate from Russia: Correction to Notice of Opportunity to Request Administrative Review, 77 FR...

  10. Test/QA Plan for Verification of Nitrate Sensors for Groundwater Remediation Monitoring

    Science.gov (United States)

    A submersible nitrate sensor is capable of collecting in-situ measurements of dissolved nitrate concentrations in groundwater. Although several types of nitrate sensors currently exist, this verification test will focus on submersible sensors equipped with a nitrate-specific ion...

  11. Sucrose mimics the light induction of Arabidopsis nitrate reductase gene transcription

    DEFF Research Database (Denmark)

    Cheng, Chi-Lien; Acedo, Gregoria N; Kristensen, Michael;

    1992-01-01

    Nitrate reductase, the first enzyme in nitrate assimilation, is located at the crossroad of two energy-consuming pathways: nitrate assimilation and carbon fixation. Light, which regulates the expression of many higher-plant carbon fixation genes, also regulates nitrate reductase gene expression. ...

  12. Monitoring of nitrate content of vegetable crops in Uzhgorod district

    Directory of Open Access Journals (Sweden)

    I.I. Mykaylo

    2013-09-01

    Full Text Available The aim of our research was to conduct a monitoring study of nitrate content in plant products of Uzhgorod district and to accomplish comparative analysis of the survey results in different periods of crop ripening. Selection of vegetable samples was carried out in Uzhgorod district in the early spring and summer periods. Determination of the nitrate content was performed using an ion-selective method at the Chemical and Toxicological Department of the Regional State Veterinary Medicine Laboratory in the Transcarpathian region of Ukraine. Vegetables were tested for nitrate content using the ion-selective method with the laboratory ion meter AI-123. Core investigation samples were crushed and homogenized. A 10.0 g weight of the investigated product, which was prepared according to MIR № 5048-89, was placed in a flat-bottomed or a conical flask, which was then filled with 50 cm3 potassium alumens solution and shaken in a shaking-machine for 5 minutes and then transferred into a measuring glass. The nitrate weight fraction in milligrams per kilogram was obtained together with the weight concentration value of nitrate ions in solution. For our study we selected vegetables grown in both public and private gardens of Uzhgorod district, namely: common onions, radishes, garden parsley, cucumbers, tomatoes, bell peppers, white cabbages, carrots and table beets. 25 samples were selected for each type of vegetable. Nitrate content was determined in the early spring growing period (from February 9 to May 27, 2011 and in the summer growing period (from June 3 to September 28, 2011, because in these particular periods we recorded the most frequent cases of food poisoning from nitrates among the population of the region. A clear trend has been traced towards increasing the nitrate content in food plant production, at levels which exceed the maximum permissible concentration (MPC. The results of our research demonstrate that the nitrate content exceeded the

  13. Global warming and changes in ocean circulation

    Energy Technology Data Exchange (ETDEWEB)

    Duffy, P.B.; Caldeira, K.C.

    1998-02-01

    This final report provides an overview of the goals and accomplishments of this project. Modeling and observational work has raised the possibility that global warming may cause changes in the circulation of the ocean. If such changes would occur they could have important climatic consequences. The first technical goal of this project was to investigate some of these possible changes in ocean circulation in a quantitative way, using a state-of -the-art numerical model of the ocean. Another goal was to develop our ocean model, a detailed three-dimensional numerical model of the ocean circulation and ocean carbon cycles. A major non-technical goal was to establish LLNL as a center of excellence in modelling the ocean circulation and carbon cycle.

  14. EOP MIT General Circulation Model (MITgcm)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data contains a regional implementation of the Massachusetts Institute of Technology general circulation model (MITgcm) at a 1-km spatial resolution for the...

  15. Sedimentary response to ocean gateway circulation changes

    Science.gov (United States)

    Heinze, Christoph; Crowley, Thomas J.

    1997-12-01

    Previous modeling studies suggested that changes in ocean gateways may have exerted a dramatic influence on the ocean circulation. In this pilot study we extend those results to examining the potential ramifications of circulation changes on the sedimentary record. A version of the Hamburg carbon cycle/sediment model is used in these sensitivity experiments. Results indicate that internal reorganization of the ocean circulation can potentially cause very large regional changes in lysocline depth (1500-3000 m) and opal deposition. These shifts are sometimes comparable in magnitude to those imposed by changes in external forcing (e.g., climate, sea level, and weathering). Comparisons of the model response with the geologic record indicate some significant levels of first-order agreement. This exercise suggests that opportunities now exist for physically based modeling of past sediment responses to circulation and climate changes.

  16. Aerosol nitrate from lightning - from sources to impacts

    Science.gov (United States)

    Tost, Holger

    2016-04-01

    Particulate nitrate is a key component on the inorganic atmospheric aerosol composition. Due to its semi-volatility, an accurate description of the budget and the impacts of nitrate aerosol are still somewhat uncertain. To address some of the impacts of nitrate, in this study we explicitly analyse the impact of aerosol nitrate from a natural source, namely lightning. As the lightning NOx emissions are only a contribution to the total NOx emissions, this example does not resemble a typical annihilation scenario, which might substantially misjudge the effect of aerosol nitrate due to the high non-linearity in the nitrate budget, but also other directly connected compounds, but tries to shed light onto the sensitivity of aerosol nitrate and its effects. On the other hand, lightning represents an emission source of NOx, which is partly injected directly in the upper troposphere, where due to its longer lifetime and the temperature dependent stability of NH4NO3 aerosol nitrate can form much easier and has a longer lifetime against decomposition. This study uses a comprehensive chemistry climate model to track the evolution of aerosol nitrate from the lightning NOx emission, via chemical processing and gas-aerosol partitioning, aerosol microphyiscal processes down to the climatic impacts of the nitrate aerosol particles via direct aerosol-radiation and aerosol-cloud interactions. All of these processes are explicitly considered with the help of state-of-the-art (parameterisation) schemes, including a comprehensive multi-phase chemistry configuration, a microphysical and chemical composition aerosol model, aerosol optical properties and a two-moment cloud microphysical scheme with explicit activation of aerosol particles into cloud droplets and the consideration of aerosol particles in ice formation processes. Furthermore, some uncertainty with respect to cloud droplet formation has been considered by using two different aerosol activation schemes. To estimate the

  17. Functional complementation of a nitrate reductase defective mutant of a green alga Dunaliella viridis by introducing the nitrate reductase gene.

    Science.gov (United States)

    Sun, Yu; Gao, Xiaoshu; Li, Qiyun; Zhang, Qingqi; Xu, Zhengkai

    2006-08-01

    Nitrate reductase (NR) catalyzes NAD (P) H dependent reduction of nitrate to nitrite. Transformation systems have been established in several species of green algae by nitrate reductase gene functional complementation. In this report, an endogenous NR cDNA (3.4 kb) and a genomic fragment (14.6 kb) containing the NR gene (DvNIA1) were isolated from the D. viridis cDNA and genomic libraries respectively. Southern blot and Northern blot analyses showed that this gene exists as a single copy in D. viridis and is induced by nitrate. To obtain a NR defective mutant as a recipient strain, D. viridis cells were treated with a chemical mutagen and then cultured on a chlorate-containing plate to enrich chlorate tolerant mutants. Southern analysis showed that one isolate, B14, had a deletion in the DvNIA1 gene region. Using electroporation conditions determined in this laboratory, plasmid pDVNR containing the intact DvNIA1 gene has been electroporated into the defective mutant B14. Strains retaining a nitrate assimilation phenotype were obtained from nitrate plates after spreading the electroporated cells. In some individual strains, transcription of the introduced gene was detected. NR activity in these strains was slightly higher than that in the defective B14 cell, but excretion of nitrite into culture media was almost as high as that of the wild-type cell. Possible episomal presence of the introduced DNA in D. viridis is discussed. PMID:16797881

  18. Physiology and interaction of nitrate and nitrite reduction in Staphylococcus carnosus.

    OpenAIRE

    Neubauer, H.; Götz, F

    1996-01-01

    Staphylococcus carnosus reduces nitrate to ammonia in two steps. (i) Nitrate was taken up and reduced to nitrite, and nitrite was subsequently excreted. (ii) After depletion of nitrate, the accumulated nitrite was imported and reduced to ammonia, which again accumulated in the medium. The localization, energy gain, and induction of the nitrate and nitrite reductases in S. carnosus were characterized. Nitrate reductase seems to be a membrane-bound enzyme involved in respiratory energy conserva...

  19. The Nordic Seas circulation and exchanges.

    OpenAIRE

    Hawker, E.J.

    2005-01-01

    The Nordic Seas provide the main oceanic connection between the Arctic and the deep global oceans via dense overflows between Greenland and Scotland, into the North Atlantic. An understanding of the circulation and exchanges of this region is vital for any consideration of the implications of high latitude climate change to variability in the Atlantic thermohaline circulation and consequences for regional (European) climate. This thesis makes use of a unique data set of near synoptic hyd...

  20. Efficient Circulation of Railway Rolling Stock

    OpenAIRE

    Alfieri, Arianna; Groot, Rutger; Kroon, Leo; Schrijver, Lex

    2002-01-01

    textabstractRailway rolling stock (locomotives, carriages, and train units) is one of the most significant cost sources for operatorsof passenger trains, both public and private. Rolling stock costsare due to material acquisition, power supply, and material maintenance. The efficient circulation of rolling stock material is therefore one of the objectives pursued. In this paper we focus on the circulation of train units on a single line. In order to utilize the train units on this line in an ...

  1. An online educational atmospheric global circulation model

    Science.gov (United States)

    Navarro, T.; Schott, C.; Forget, F.

    2015-10-01

    As part of online courses on exoplanets of Observatoire de Paris, an online tool designed to vizualise outputs of the Laboratoire de Métérologie Dynamique (LMD) Global Circulation Model (GCM) for various atmospheric circulation regimes has been developed. It includes the possibility for students to visualize 1D and 2D plots along with animations of atmospheric quantities such as temperature, winds, surface pressure, mass flux, etc... from a state-of-the-art model.

  2. STRUCTURES OF CIRCULANT INVERSE M-MATRICES

    Institute of Scientific and Technical Information of China (English)

    Yurui Lin; Linzhang Lu

    2007-01-01

    In this paper,we present a useful result on the structures of circulant inverse Mis not a positive matrix and not equal to c0I,then A is an inverse M-matrix if and only if there exists a positive integer k,which is a proper factor of n,such that cjk>0 for The result is then extended to the so-called generalized circulant inverse M-matrices.

  3. Influence of organic carbon sources and isotope exchange processes between water and nitrate on the fractionation of the stable isotopes 15N/14N and 18O/16O in dissolved nitrate during microbial dentrification in groundwater

    International Nuclear Information System (INIS)

    Stable isotopes of nitrate are commonly used to determine sources and degradation of nitrate. In this study, nitrite oxidizing bacteria were found to promote an oxygen isotope exchange between water and nitrate under anoxic conditions. Also, different carbon sources were found to influence the enrichment of stable isotopes in nitrate during microbial denitrification. Both results refine the stable isotope model of nitrate in respect to nitrate source determination and microbial nitrate reduction.

  4. Microbial response to nitrate treatment in offshore oil fields

    Energy Technology Data Exchange (ETDEWEB)

    Boedtker, Gunhild

    2009-07-01

    North Sea oil reservoirs are often injected with deaerated sea water in order to enhance oil recovery. The high sulphate content of sea water combined with the anoxic conditions stimulates growth of sulphate-reducing bacteria (SRB) in the water injection system and the reservoir. SRB produce the highly toxic and corrosive gas hydrogen sulphide (HZS) during anaerobic respiration with sulphate. Accumulation of HZS leads to corrosion and reservoir souring, which may result in reduced gas quality, separation problems and increased maintenance costs. Biocides have traditionally been used to prevent SRB activity in North Sea oil fields. During the last decade, however, the environmentally sound method of nitrate treatment has replaced biocides on several fields. The method is based on shifting the microbial activity from sulphate reduction to nitrate reduction by introducing nitrate as an alternative electron acceptor for anaerobic respiration. Results presented in the current thesis show that nitrate treatment has resulted in long-term inhibition of SRB activity and a reduction in corrosion of up to 40% in sea water injection systems at the Veslefrikk and Gullfaks oil fields. Molecular analysis (PCR-DGGE) of pipeline biofilm from Veslefrikk showed that sulphide-oxidizing nitrate-reducing bacteria (NR-SOB) constituted the major metabolic group during nitrate treatment, and that the bacterial community composition remained stable during years. Reduction in sulphide produced from the Gullfaks field showed that nitrate treatment was effective also at reservoir level. Analysis of back flowed injection water from a nitrate-treated Statfjord reservoir showed that heterotrophic nitrate-reducing bacteria (hNRB) constituted the major metabolic group, and that the in situ HZS level was 10 fold lower than experienced during biocides treatment and 100 fold lower than experienced during produced water reinjection (PWRI). At the Norne oil field oxic sea water is injected along with

  5. Surgical myocardial revascularization without extracorporeal circulation

    Directory of Open Access Journals (Sweden)

    Salomón Soriano Ordinola Rojas

    2003-05-01

    Full Text Available OBJECTIVE: To assess the immediate postoperative period of patients undergoing myocardial revascularization without extracorporeal circulation with different types of grafts. METHODS: One hundred and twelve patients, 89 (79.5% of whom were males, were revascularized without extracorporeal circulation. Their ages ranged from 39 to 85 years. The criteria for indicating myocardial revascularization without extracorporeal circulation were as follows: revascularized coronary artery caliber > 1.5 mm, lack of intramyocardial trajectory on coronary angiography, noncalcified coronary arteries, and tolerance of the heart to the different rotation maneuvers. RESULTS: Myocardial revascularization without extracorporeal circulation was performed in 112 patients. Three were converted to extracorporeal circulation, which required a longer hospital stay but did not impact mortality. During the procedure, the following events were observed: atrial fibrillation in 10 patients, ventricular fibrillation in 4, total transient atrioventricular block in 2, ventricular extrasystoles in 58, use of a device to retrieve red blood cells in 53, blood transfusion in 8, and arterial hypotension in 89 patients. Coronary angiography was performed in 20 patients on the seventh postoperative day when the grafts were patent. CONCLUSION: Myocardial revascularization without extracorporeal circulation is a reproducible technique that is an alternative for treating ischemic heart disease.

  6. Southern Meridional Atmospheric Circulation Associated with IOD

    Institute of Scientific and Technical Information of China (English)

    LIU Na; CHEN Hongxia

    2006-01-01

    Using the monthly wind and sea surface temperature (SST) data, southern meridional atmospheric circulation cells associated with the Indian Ocean Dipole Mode (IOD) events in the Indian Ocean are for the first time described and examined. The divergent wind and pressure vertical velocity are employed for the identification of atmospheric circulation cells. During the four different phases of the positive IOD events, the anomalous meridional Hadley circulation over the western Indian Ocean shows that the air rises in the tropics, flows poleward in the upper troposphere, sinks in the subtropics, and returns back to the tropics in the lower troposphere. The anomalous Hadley circulation over the eastern Indian Ocean is opposite to that over the western Indian Ocean. During positive IOD events, the meridional Hadley circulation over the eastern Indian Ocean is weakened while it is strengthened over the western Indian Ocean. Correlation analysis between the IOD index and the indices of the Hadley cells also proves that, the atmospheric circulation patterns are evident in every IOD event over the period of record.

  7. Global climate and ocean circulation on an aquaplanet ocean-atmosphere general circulation model

    OpenAIRE

    Smith, R.; Dubois, C.; Marotzke, J.

    2006-01-01

    A low-resolution coupled ocean–atmosphere general circulation model (OAGCM) is used to study the characteristics of the large-scale ocean circulation and its climatic impacts in a series of global coupled aquaplanet experiments. Three configurations, designed to produce fundamentally different ocean circulation regimes, are considered. The first has no obstruction to zonal flow, the second contains a low barrier that blocks zonal flow in the ocean at all latitudes, creating a single enclosed ...

  8. Nitrate transport and its regulation by O2 in Pseudomonas aeruginosa.

    Science.gov (United States)

    Hernandez, D; Dias, F M; Rowe, J J

    1991-04-01

    Pseudomonas aeruginosa is an obligate respirer which can utilize nitrate as a terminal electron acceptor under anaerobic conditions (denitrification). Immediate, transient regulation of nitrate respiration is mediated by oxygen through the inhibition of nitrate uptake. In order to gain an understanding of the bioenergetics of nitrate transport and its regulation by oxygen, the effects of various metabolic inhibitors on the uptake process and on oxygen regulation were investigated. Nitrate uptake was stimulated by the protonophores carbonyl cyanide m-chlorophenylhydrazone and 2,4-dinitrophenol, indicating that nitrate uptake is not strictly energized by, but may be affected by the proton motive force. Oxygen regulation of nitrate uptake might in part be through redox-sensitive thiol groups since N-ethylmaleimide at high concentrations decreased the rate of nitrate transport. Cells grown with tungstate (deficient in nitrate reductase activity) and azide-treated cells transported nitrate at significantly lower rates than untreated cells, indicating that physiological rates of nitrate transport are dependent on nitrate reduction. Furthermore, tungstate grown cells transported nitrate only in the presence of nitrite, lending support to the nitrate/nitrite antiport model for transport. Oxygen regulation of nitrate transport was relieved (10% that of typical anaerobic rates) by the cytochrome oxygen reductase inhibitors carbon monoxide and cyanide. PMID:1910283

  9. Difficulties in the Nitrates Directive Implementation in Romania

    Directory of Open Access Journals (Sweden)

    MIHĂIESCU Tania

    2010-12-01

    Full Text Available The EU Nitrates Directive (Council Directive 91/676/EEC forms an integrate part of the Water FrameworkDirective and is one of the key instruments in the protection of waters against agricultural pressures [6]. The NitratesDirective aims to protect water quality across Europe by reducing water pollution caused or induced by nitrates fromagricultural sources and by promoting the use of good agricultural practices. Implementation of this directive hasproved to be a major challenge for Member States, demanding vast technical resources for the characterization and riskassessments and for developing and operating the associated monitoring programmes, in order to quantify the efficiencyof the implemented measures. The 2010 EC's report on the implementation of the Nitrates Directive shows that thepressure from agriculture with respect to surface and groundwater nitrate pollution has decreased in many MemberStates, although still, agriculture contributes largely to nitrogen loads to surface and ground waters [7]. However,despite these encouraging trends, the report reveals a number of regions where nitrate levels, according to monitoringdata, are worrying; one among them is also the southern part of Romania. Although major pollutant sources such aslarge intensive rearing of poultry and pig farms ceased or conformed to the IPPC directive, achievement of the Nitratesdirective goals is still far away from realization due to livestock husbandry farms bad waste management and due to thelack of waste water treatment stations in rural settlements. Accomplishment of the nitrates directive demands has to berealized, in the case of Romania, by a concertated array of measures aimed at reducing pollution both at major and lessimportant sources [9], [10].

  10. Analytical Characterization of the Thorium Nitrate Stockpile

    Energy Technology Data Exchange (ETDEWEB)

    Mattus, CH

    2003-12-30

    For several years, Oak Ridge National Laboratory (ORNL) has been supporting the Defense Logistics Agency-Defense National Stockpile Center with stewardship of a thorium nitrate (ThN) stockpile. The effort for fiscal year 2002 was to prepare a sampling and analysis plan and to use the activities developed in the plan to characterize the ThN stockpile. The sampling was performed in June and July 2002 by RWE NUKEM with oversight by ORNL personnel. The analysis was performed by Southwest Research Institute of San Antonio, Texas, and data validation was performed by NFT, Inc., of Oak Ridge, Tennessee. Of the {approx} 21,000 drums in the stockpile, 99 were sampled and 53 were analyzed for total metals composition, radiological constituents (using alpha and gamma spectrometry), and oxidizing characteristics. Each lot at the Curtis Bay Depot was sampled. Several of the samples were also analyzed for density. The average density of the domestic ThN was found to be 1.89 {+-} 0.08 g/cm{sup 3}. The oxidizer test was performed following procedures issued by the United Nations in 1999. Test results indicated that none of the samples tested was a Division 5.1 oxidizer per Department of Transportation definition. The samples were analyzed for total metals following the U.S. Environmental Protection Agency methods SW-846-6010B and 6020 (EPA 2003) using a combination of inductively coupled plasma--atomic emission spectroscopy and inductively coupled plasma--mass spectroscopy techniques. The results were used to compare the composition of the eight Resource Conservation and Recovery Act metals present in the sample (arsenic, barium, cadmium, chromium, lead, mercury, selenium, and silver) to regulatory limits. None of the samples was found to be hazardous for toxicity characteristics. The radiological analyses confirmed, when possible, the results obtained by the inductively coupled plasma analyses. These results--combined with the historical process knowledge acquired on the material

  11. Circulation model for water circulation and purification in a water Cerenkov detector

    Institute of Scientific and Technical Information of China (English)

    LU Hao-Qi; YANG Chang-Gen; WANG Ling-Yu; XU Ji-Lei; WANG aui-Guang; WANG Zhi-Min; WANG Yi-Fang

    2009-01-01

    Owing to its low cost and good transparency, highly purified water is widely used as a medium in large water Cerenkov detector experiments. The water circulation and purification system is usually needed to keep the water in good quality. In this work, a practical circulation model is built to describe the variation of the water resistivity in the circulation process and compared with the data obtained from a prototype experiment. The successful test of the model makes it useful in the future design and optimization of the circulation/purification system.

  12. Experimental and numerical investigation of natural circulation phenomena in a rectangular natural circulation loop

    International Nuclear Information System (INIS)

    Natural circulation is the key phenomena in the passive cooling systems. Thus, it is important to study the flow characteristics and heat transfer behavior in natural circulation. The natural circulation phenomena in steady state and transient form is investigated using 3D CFD simulations, carried out using OpenFoam 2.2.0. The first part consists of a steady-state study, in which the results are validated by data available from a set of experiments conducted over a range of heater power (130W-360W). The second part consists of a transient study of flow development and establishment of natural circulation within this loop. (author)

  13. Production of organic nitrates from hydroxyl and nitrate radical reaction with propylene

    Energy Technology Data Exchange (ETDEWEB)

    Shepson, P.B.; Edney, E.O.; Kleindienst, T.E.; Pittman, J.H.; Namie, G.R.; Cupitt, L.T.

    1985-09-01

    Measurements of the gas-phase production rates of ..cap alpha..-(nitrooxy)acetone, propylene glycol dinitrate (PGDN), 2-hydroxypropyl nitrate (2-HPN), and 2-nitrooxy)propyl alcohol (2-NPA) in a C/sub 3/H/sub 6//N/sub 2/O/sup 5//air dark reaction and a C/sub 3/H/sub 6//NO/sub x/ air irradiation are reported. The probable operative reaction mechanisms are discussed, and the branching ratios for peroxy radical reaction with NO via RO/sub 2/ + NO ..-->.. RONO/sub 2/ vs. RO/sub 2/ + NO ..-->.. RO + NO/sub 2/ are estimated for CH/sub 3/CH(OO)CH/sub 2/OH and CH/sub 3/CH(OH)C-H/sub 2/OO radicals.

  14. Investigating the Effect of Three Nitrate Fertilizers on Nitrate Leaching under the Root Zone in Clay Loam Soil

    Directory of Open Access Journals (Sweden)

    Thamer A. Mohammed

    2009-01-01

    Full Text Available Problem statement: Nitrogen fertilizer is recognized as an important factor in crop’s yield level, however more application of N fertilizers in the soil have some adverse effects on environment and especially on ground water contamination. Perception and recognition the factors influencing nitrate transport through soil profile is helpful for fertilizer management to minimize adverse impacts on environment and nitrate leaching below the root zone. Approach: In this study, 9 large cylindrical lysimeters with 1 m height and 0.5 m diameter were filled with clay loam soil and planted with maize to investigate nitrate leaching under different types of N-fertilizer, chemical fertilizer, activated sludge and organic manure. Nitrate concentration in the soil and drainage water samples were analyzed by spectrophotometer method and the mass of nitrate was calculated in soil and drainage water. Crop productions for different treatments were compared too. Results: Results showed that cumulative mass of nitrate leaching from organic fertilizer was greater than the other treatments (229 kg ha-1. Organic manure had the greatest nitrate accumulation in soil (15.17 mg kg-1, which was significantly greater than chemical fertilizer. Conclusions/Recommendations: experimental results showed that manure application could result in NO3--N accumulation increase in the deeper soil profiles compared with activated sludge. Results showed that maize production was significantly higher under activated sludge fertilizer. Observations made in the current study suggested activated sludge fertilizer due to a higher crop production with same level of ground water contamination, especially in clay loam soils.

  15. Summary of Remediated Nitrate Salt Surrogate Formulation and Testing

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Geoffrey Wayne [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Leonard, Philip [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hartline, Ernest Leon [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Tian, Hongzhao [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-05-05

    High Explosives Science and Technology (M-7) completed all required formulation and testing of Remediated Nitrate Salt (RNS) surrogates on April 27, 2016 as specified in PLAN-TA9-2443 Rev B, "Remediated Nitrate Salt (RNS) Surrogate Formulation and Testing Standard Procedure", released February 16, 2016. This report summarizes the results of the work and also includes additional documentation required in that test plan. All formulation and testing was carried out according to PLAN-TA9-2443 Rev B. The work was carried out in three rounds, with the full matrix of samples formulated and tested in each round. Results from the first round of formulation and testing were documented in memorandum M7-J6-6042, " Results from First Round of Remediated Nitrate Salt Surrogate Formulation and Testing." Results from the second round of formulation and testing were documented in M7-16-6053 , "Results from the Second Round of Remediated Nitrate Salt Surrogate Formulation and Testing." Initial results from the third round were documented in M7-16-6057, "Initial Results from the Third Round of Remediated Nitrate Salt Formulation and Testing."

  16. Nitrate and ammonia as nitrogen sources for deep subsurface microorganisms

    Directory of Open Access Journals (Sweden)

    Heini eKutvonen

    2015-10-01

    Full Text Available We investigated the N-utilizing bacterial community in anoxic brackish groundwater of the low and intermediate level nuclear waste repository cave in Olkiluoto, Finland, at 100 m depth using 15N-based stable isotope probing (SIP and enrichment with 14/15N-ammonium or 14/15N-nitrate complemented with methane. 28 days of incubation at 12°C increased the concentration of bacterial 16S rRNA and nitrate reductase (narG gene copies in the substrate amended microcosms simultaneously with a radical drop in the overall bacterial diversity and OTU richness. Hydrogenophaga/Malikia were enriched in all substrate amended microcosms and Methylobacter in the ammonium and ammonium+methane supplemented microcosms. Sulfuricurvum was especially abundant in the nitrate+methane treatment and the unamended incubation control. Membrane-bound nitrate reductase genes (narG from Polarimonas sp. were detected in the original groundwater, while Burkholderia, Methylibium and Pseudomonas narG genes were enriched due to substrate supplements. Identified amoA genes belonged to Nitrosomonas sp. 15N-SIP revealed that Burkholderiales and Rhizobiales clades belonging to the minority groups in the original groundwater used 15N from ammonium and nitrate as N source indicating an important ecological function of these bacteria, despite their low number, in the groundwater N cycle in Olkiluoto bedrock system.

  17. Nitrate and ammonia as nitrogen sources for deep subsurface microorganisms

    Science.gov (United States)

    Kutvonen, Heini; Rajala, Pauliina; Carpén, Leena; Bomberg, Malin

    2015-01-01

    We investigated the N-utilizing bacterial community in anoxic brackish groundwater of the low and intermediate level nuclear waste repository cave in Olkiluoto, Finland, at 100 m depth using 15N-based stable isotope probing (SIP) and enrichment with 14∕15N-ammonium or 14∕15N-nitrate complemented with methane. Twenty-eight days of incubation at 12°C increased the concentration of bacterial 16S rRNA and nitrate reductase (narG) gene copies in the substrate amended microcosms simultaneously with a radical drop in the overall bacterial diversity and OTU richness. Hydrogenophaga/Malikia were enriched in all substrate amended microcosms and Methylobacter in the ammonium and ammonium+methane supplemented microcosms. Sulfuricurvum was especially abundant in the nitrate+methane treatment and the unamended incubation control. Membrane-bound nitrate reductase genes (narG) from Polarimonas sp. were detected in the original groundwater, while Burkholderia, Methylibium, and Pseudomonas narG genes were enriched due to substrate supplements. Identified amoA genes belonged to Nitrosomonas sp. 15N-SIP revealed that Burkholderiales and Rhizobiales clades belonging to the minority groups in the original groundwater used 15N from ammonium and nitrate as N source indicating an important ecological function of these bacteria, despite their low number, in the groundwater N cycle in Olkiluoto bedrock system. PMID:26528251

  18. Hydrogen anode for nitrate waste destruction. Revision 2

    International Nuclear Information System (INIS)

    Large quantities of radioactive and hazardous wastes have been generated from nuclear materials production during the past fifty years. Processes are under evaluation to separate the high level radioactive species from the waste and store them permanently in the form of durable solids. The schemes proposed will separate the high level radioactive components, cesium-137 and strontium-90, into a small volume for incorporation into a glass wasteform. The remaining low-level radioactive waste contain species such as nitrites and nitrates that are capable of contaminating ground water. Electrochemical destruction of the nitrate and nitrite before permanent storage has been proposed. Not only will the electrochemical processing destroy these species, the volume of the waste could also be reduced. The use of a hydrogen gas-fed anode and an acid anolyte in an electrochemical cell used to destroy nitrate was demonstrated. A mixed Na2SO4/H2SO4 anolyte was shown to favor the nitrate cell performance, and the generation of a higher hydroxide ion concentration in the catholyte. The suggested scheme is an apparent method of sodium sulfate disposal and a possible means through which ammonia (to ammonium sulfate, fertilizer) and hydrogen gas could be recycled through the anode side of the reactor. This could result in a substantial savings in the operation of a nitrate destruction cell

  19. Sensitive Immunoassays of Nitrated Fibrinogen in Human Biofluids

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Zhiwen; Wu, Hong; Du, Dan; Wang, Jun; Wang, Hua; Qian, Weijun; Bigelow, Diana J.; Pounds, Joel G.; Smith, Richard D.; Lin, Yuehe

    2010-05-05

    Three new sandwich immunoassays for detection of nitrated biomarker have been established with potential applications in biomedical studies and clinical practice. In this study, nitrated human fibrinogen, a potential oxidative stress biomarker for several pathologies, was chosen as the target. To improve the sensitivity and overcome the interference caused by the complexity of human biofluids, we developed three sandwich strategies using various combinations of primary antibody and secondary antibody. All three strategies demonstrated high sensitivity and selectivity towards nitrated forms of fibrinogen in buffer, but their performances were dramatically reduced when tested with human plasma and serum samples. Systematically optimizations were carried out to investigate the effects of numerous factors, including sampling, coating, blocking, and immunoreactions. Our final optimization results indicate that two of these strategies retain sufficient sensitivity and selectivity for use as assays in human physiological samples. Specifically, detection limits reached the pM level and the linear response ranges were up to nM level with a correlation coefficient > 0.99. To our best knowledge, this is the first example of using an electrochemical immunoassay for a nitrated biomarker in a physiological fluid. This novel approach provides a rapid, sensitive, selective, cost efficient and robust bioassay for detection of oxidative stress in pathology and for clinical applications. Moreover, the sandwich strategies developed in this paper can be readily used to establish effective methods targeting other nitration biomarkers.

  20. Isoprene nitrates: preparation, separation, identification, yields, and atmospheric chemistry

    Directory of Open Access Journals (Sweden)

    A. L. Lockwood

    2010-04-01

    Full Text Available Isoprene is an important atmospheric volatile organic compound involved in ozone production and NOx (NO+NO2 sequestration and transport. Isoprene reaction with OH in the presence of NO can form either isoprene nitrates or convert NO to NO2 which can photolyze to form ozone. While it has been shown that isoprene nitrate production can represent an important sink for NOx in forest impacted environments, there is little experimental knowledge of the relative importance of the individual isoprene nitrate isomers, each of which has a different fate and reactivity. In this work, we have identified the 8 individual isomers and determined their total and individual production yields. The overall yield of isoprene nitrates at atmospheric pressure and 295 K was found to be 0.070(+0.025/–0.015. Three isomers, the (4,3-IN, (1,2-IN and Z-(4,1-IN represent 90% of the total IN yield. We also determined the ozone rate constants for three of the isomers, and have calculated their atmospheric lifetimes, which range from ~1–2 h, making their oxidation products likely more important as atmospheric organic nitrates and sinks for nitrogen.

  1. Reduction of nitrate from groundwater: powder catalysts and catalytic membrane

    Institute of Scientific and Technical Information of China (English)

    CHEN Ying-xu; ZHANG Yan; LIU Hong-yuan

    2003-01-01

    The reduction of nitrate contaminant in groundwater has gained renewed and intensive attention due to the environmental problems and health risks. Catalytic denetrification presents one of the most promising approaches for the removal of nitrate from water. Catalytic nitrate reduction from water by powder catalysts and catalytic membrane in a batch reactor was studied. And the effects of the initial concentration, the amounts of catalyst, and the flux H2 on the nitrate reduction were also discussed. The results demonstrated that nitrate reduction activity and the selectivity to nitrogen gas were mainly controlled by diffusion limitations and the mass transfer of the reactants. The selectivity can improved while retaining a high catalytic activity under controlled diffusion condition or the intensification of the mass transfer, and a good reaction condition. The total nitrogen removal efficiency reached above 80%. Moreover, catalytic membrane can create a high effective gas/liquid/solid interface, and show a good selectivity to nitrogen in comparative with the powder catalyst, the selectivity to nitrogen was improved from 73.4% to 89.4%.

  2. Sulfide elimination by intermittent nitrate dosing in sewer sediments

    Institute of Scientific and Technical Information of China (English)

    Yanchen Liu; Chen Wu; Xiaohong Zhou; David Z.Zhu; Hanchang Shi

    2015-01-01

    The formation of hydrogen sulfide in biofilms and sediments in sewer systems can cause severe pipe corrosions and health hazards,and requires expensive programs for its prevention.The aim of this study is to propose a new control strategy and the optimal condition for sulfide elimination by intermittent nitrate dosing in sewer sediments.The study was carried out based on lab-scale experiments and batch tests using real sewer sediments.The intermittent nitrate dosing mode and the optimal control condition were investigated.The results indicated that the sulfide-intermittent-elimination strategy by nitrate dosing is advantageous for controlling sulfide accumulation in sewer sediment.The oxidation-reduction potential is a sensitive indicator parameter that can reflect the control effect and the minimum N/S (nitrate/sulfide)ratio with slight excess nitrate is necessary for optimal conditions ofefficient sulfide control with lower carbon source loss.The opth-nal control condition is feasible for the sulfide elimination in sewer systems.

  3. Engineered bioretention for removal of nitrate from stormwater runoff.

    Science.gov (United States)

    Kim, Hunho; Seagren, Eric A; Davis, Allen P

    2003-01-01

    A bioretention unit is a simple, plant- and soil-based, low-impact treatment and infiltration facility for treating stormwater runoff in developed areas. Nitrate, however, is not attenuated in conventional bioretention facilities. Thus, this study systematically evaluated a reengineered concept of bioretention for nitrate removal via microbial denitrification, which incorporates a continuously submerged anoxic zone with an overdrain. Experimental studies were performed in four phases. In the first two phases, column studies demonstrated that, overall, newspaper is the best solid-phase electron-donor substrate for denitrification out of the set studied (alfalfa, leaf mulch compost, newspaper, sawdust, wheat straw, wood chips, and elemental sulfur) based on superior nitrate removal and effluent water quality. The nitrate loading and hydraulic loading studies in the second phase provided design information. In the third phase, system viability after 30- and 84-day dormant periods was evaluated in column studies, demonstrating that newspaper-supported biological denitrification should be effective under conditions of intermittent loadings. Finally, in the fourth phase, pilot-scale bioretention studies demonstrated the effectiveness of the proposed design, showing nitrate plus nitrite mass removals of up to 80%. These results indicate that engineered bioretention for the removal of nitrogen from stormwater runoff has the potential for successful application as an urban stormwater treatment practice.

  4. Effects of mineral dust on global atmospheric nitrate concentrations

    Science.gov (United States)

    Karydis, Vlassis; Tsimpidi, Alexandra; Astitha, Marina; Lelieveld, Jos

    2014-05-01

    Inorganic particulate nitrate contributes significantly to the total aerosol mass. While nitrate is predominantly present in the submicron mode, coarse mode aerosol nitrate can also be produced by adsorption of nitric acid onto soil particles. Naturally emitted particles affect the phase partitioning of nitrate, especially in areas where dust comprises a significant portion of total particulate matter, and the simulation of these effects can considerably improve model predictions. However, most thermodynamic models used in global studies lack a realistic treatment of crustal species. This work aims to improve the representation of nitrate aerosols in the global chemistry climate model EMAC, and addresses the shortcomings of previous models. EMAC calculates the aerosol microphysics and gas/aerosol partitioning by using the GMXe aerosol module. The aerosol size distribution is described by 7 interacting lognormal modes (4 hydrophilic and 3 hydrophobic modes). An advanced dust emission module also accounts for the soil particle size distribution of different deserts worldwide. Gas/aerosol partitioning is simulated using the ISORROPIA-II thermodynamic equilibrium model which considers the interaction of K(+), Ca(+2), Mg(+2), NH4(+), Na(+), SO4(-2), NO3(-), Cl(-), H2O aerosol components. The EMAC model is tested in long-term simulations covering the years 2005-2008. Model predictions are compared with data from the European network EMEP, the IMPROVE network in North America, and the EANET Network in East Asia.

  5. Organic nitrate aerosol formation via NO3 + BVOC in the Southeastern US

    Science.gov (United States)

    Ayres, B. R.; Allen, H. M.; Draper, D. C.; Brown, S. S.; Wild, R. J.; Jimenez, J. L.; Day, D. A.; Campuzano-Jost, P.; Hu, W.; de Gouw, J.; Koss, A.; Cohen, R. C.; Duffey, K. C.; Romer, P.; Baumann, K.; Edgerton, E.; Takahama, S.; Thornton, J. A.; Lee, B. H.; Lopez-Hilfiker, F. D.; Mohr, C.; Goldstein, A. H.; Olson, K.; Fry, J. L.

    2015-06-01

    Gas- and aerosol-phase measurements of oxidants, biogenic volatile organic compounds (BVOC) and organic nitrates made during the Southern Oxidant and Aerosol Study (SOAS campaign, Summer 2013) in central Alabama show that nitrate radical (NO3) reaction with monoterpenes leads to significant secondary aerosol formation. Cumulative losses of NO3 to terpenes are calculated and correlated to gas and aerosol organic nitrate concentrations made during the campaign. Correlation of NO3 radical consumption to organic nitrate aerosol as measured by Aerosol Mass Spectrometry (AMS) and Thermal Dissociation - Laser Induced Fluorescence (TD-LIF) suggests a range of molar yield of aerosol phase monoterpene nitrates of 23-44 %. Compounds observed via chemical ionization mass spectrometry (CIMS) are correlated to predicted nitrate loss to terpenes and show C10H17NO5, likely a hydroperoxy nitrate, is a major nitrate oxidized terpene product being incorporated into aerosols. The comparable isoprene product C5H9NO5 was observed to contribute less than 0.5 % of the total organic nitrate in the aerosol-phase and correlations show that it is principally a gas-phase product from nitrate oxidation of isoprene. Organic nitrates comprise between 30 and 45 % of the NOy budget during SOAS. Inorganic nitrates were also monitored and showed that during incidents of increased coarse-mode mineral dust, HNO3 uptake produced nitrate aerosol mass loading comparable to that of organic nitrate produced via NO3 + BVOC.

  6. Organic nitrate aerosol formation via NO3 + biogenic volatile organic compounds in the southeastern United States

    Science.gov (United States)

    Ayres, B. R.; Allen, H. M.; Draper, D. C.; Brown, S. S.; Wild, R. J.; Jimenez, J. L.; Day, D. A.; Campuzano-Jost, P.; Hu, W.; de Gouw, J.; Koss, A.; Cohen, R. C.; Duffey, K. C.; Romer, P.; Baumann, K.; Edgerton, E.; Takahama, S.; Thornton, J. A.; Lee, B. H.; Lopez-Hilfiker, F. D.; Mohr, C.; Wennberg, P. O.; Nguyen, T. B.; Teng, A.; Goldstein, A. H.; Olson, K.; Fry, J. L.

    2015-12-01

    Gas- and aerosol-phase measurements of oxidants, biogenic volatile organic compounds (BVOCs) and organic nitrates made during the Southern Oxidant and Aerosol Study (SOAS campaign, Summer 2013) in central Alabama show that a nitrate radical (NO3) reaction with monoterpenes leads to significant secondary aerosol formation. Cumulative losses of NO3 to terpenes are correlated with increase in gas- and aerosol-organic nitrate concentrations made during the campaign. Correlation of NO3 radical consumption to organic nitrate aerosol formation as measured by aerosol mass spectrometry and thermal dissociation laser-induced fluorescence suggests a molar yield of aerosol-phase monoterpene nitrates of 23-44 %. Compounds observed via chemical ionization mass spectrometry (CIMS) are correlated to predicted nitrate loss to BVOCs and show C10H17NO5, likely a hydroperoxy nitrate, is a major nitrate-oxidized terpene product being incorporated into aerosols. The comparable isoprene product C5H9NO5 was observed to contribute less than 1 % of the total organic nitrate in the aerosol phase and correlations show that it is principally a gas-phase product from nitrate oxidation of isoprene. Organic nitrates comprise between 30 and 45 % of the NOy budget during SOAS. Inorganic nitrates were also monitored and showed that during incidents of increased coarse-mode mineral dust, HNO3 uptake produced nitrate aerosol mass loading at a rate comparable to that of organic nitrate produced via NO3 + BVOCs.

  7. Organic nitrate aerosol formation via NO3 + BVOC in the Southeastern US

    Directory of Open Access Journals (Sweden)

    B. R. Ayres

    2015-06-01

    Full Text Available Gas- and aerosol-phase measurements of oxidants, biogenic volatile organic compounds (BVOC and organic nitrates made during the Southern Oxidant and Aerosol Study (SOAS campaign, Summer 2013 in central Alabama show that nitrate radical (NO3 reaction with monoterpenes leads to significant secondary aerosol formation. Cumulative losses of NO3 to terpenes are calculated and correlated to gas and aerosol organic nitrate concentrations made during the campaign. Correlation of NO3 radical consumption to organic nitrate aerosol as measured by Aerosol Mass Spectrometry (AMS and Thermal Dissociation – Laser Induced Fluorescence (TD-LIF suggests a range of molar yield of aerosol phase monoterpene nitrates of 23–44 %. Compounds observed via chemical ionization mass spectrometry (CIMS are correlated to predicted nitrate loss to terpenes and show C10H17NO5, likely a hydroperoxy nitrate, is a major nitrate oxidized terpene product being incorporated into aerosols. The comparable isoprene product C5H9NO5 was observed to contribute less than 0.5 % of the total organic nitrate in the aerosol-phase and correlations show that it is principally a gas-phase product from nitrate oxidation of isoprene. Organic nitrates comprise between 30 and 45 % of the NOy budget during SOAS. Inorganic nitrates were also monitored and showed that during incidents of increased coarse-mode mineral dust, HNO3 uptake produced nitrate aerosol mass loading comparable to that of organic nitrate produced via NO3 + BVOC.

  8. Nitrate in Danish groundwater during the last 60 years

    DEFF Research Database (Denmark)

    Hansen, B; Thorling, L; Dalgaard, Tommy;

    This presentation assesses the long-term development in the oxic groundwater nitrate concentration and nitrogen (N) loss due to intensive farming in Denmark. Firstly, up to 20-year time-series from the national groundwater monitoring network enable a statistically systematic analysis...... two dataset. The development in the nitrate concentration of oxic groundwater clearly mirrors the development in the national agricultural N surplus, and a corresponding trend reversal is found in groundwater (see Figure 1). Regulation and technical improvements in the intensive farming in Denmark...... have succeeded in decreasing the N surplus by 40% since the mid 1980s while at the same time maintaining crop yields and increasing the animal production of especially pigs. Trend analyses prove that the youngest (0-15 years old) oxic groundwater shows more pronounced significant downward nitrate...

  9. Mass-balance model for predicting nitrate in ground water

    Science.gov (United States)

    Frimpter, Michael H.; Donohue, John J.; Rapacz, Michael V.

    1990-01-01

    A mass-balance accounting model can be used to guide the management of septic systems and fertilizers to control the degradation of ground-water quality in zones of an aquifer that contribute water to public-supply wells. The nitrate concentration of the mixture in the well can be predicted for steady-state conditions by calculating the concentration that results from the total weight of nitrogen and total volume of water entering the zone of contribution to the well. These calculations will allow water-quality managers to predict the nitrate concentrations that would be produced by different types and levels of development, and to plan development accordingly. Computations for different development schemes provide a technical basis for planners and managers to compare water-quality effects and to select alternatives that limit nitrate concentration in wells.

  10. Handling of Ammonium Nitrate Mother-Liquid Radiochemical Production - 13089

    International Nuclear Information System (INIS)

    The aim of the work is to develop a basic technology of decomposition of ammonium nitrate stock solutions produced in radiochemical enterprises engaged in the reprocessing of irradiated nuclear fuel and fabrication of fresh fuel. It was necessary to work out how to conduct a one-step thermal decomposition of ammonium nitrate, select and test the catalysts for this process and to prepare proposals for recycling condensation. Necessary accessories were added to a laboratory equipment installation decomposition of ammonium nitrate. It is tested several types of reducing agents and two types of catalyst to neutralize the nitrogen oxides. It is conducted testing of modes of the process to produce condensation, suitable for use in the conversion of a new technological scheme of production. It is studied the structure of the catalysts before and after their use in a laboratory setting. It is tested the selected catalyst in the optimal range for 48 hours of continuous operation. (authors)

  11. Agriculture causes nitrate fertilization of remote alpine lakes

    Science.gov (United States)

    Hundey, E. J.; Russell, S. D.; Longstaffe, F. J.; Moser, K. A.

    2016-02-01

    Humans have altered Earth's nitrogen cycle so dramatically that reactive nitrogen (Nr) has doubled. This has increased Nr in aquatic ecosystems, which can lead to reduced water quality and ecosystem health. Apportioning sources of Nr to specific ecosystems, however, continues to be challenging, despite this knowledge being critical for mitigation and protection of water resources. Here we use Δ17O, δ18O and δ15N from Uinta Mountain (Utah, USA) snow, inflow and lake nitrate in combination with a Bayesian-based stable isotope mixing model, to show that at least 70% of nitrates in aquatic systems are anthropogenic and arrive via the atmosphere. Moreover, agricultural activities, specifically nitrate- and ammonium-based fertilizer use, are contributing most (~60%) Nr, and data from other North American alpine lakes suggest this is a widespread phenomenon. Our findings offer a pathway towards more effective mitigation, but point to challenges in balancing food production with protection of important water resources.

  12. Assessing bottled water nitrate concentrations to evaluate total drinking water nitrate exposure and risk of birth defects

    Science.gov (United States)

    Weyer, Peter J.; Brender, Jean D.; Romitti, Paul A.; Kantamneni, Jiji R.; Crawford, David; Sharkey, Joseph R.; Shinde, Mayura; Horel, Scott A.; Vuong, Ann M.; Langlois, Peter H.

    2016-01-01

    Previous epidemiologic studies of maternal exposure to drinking water nitrate did not account for bottled water consumption. The objective of this National Birth Defects Prevention Study (NBDPS) (USA) analysis was to assess the impact of bottled water use on the relation between maternal exposure to drinking water nitrate and selected birth defects in infants born during 1997–2005. Prenatal residences of 1,410 mothers reporting exclusive bottled water use were geocoded and mapped; 326 bottled water samples were collected and analyzed using Environmental Protection Agency Method 300.0. Median bottled water nitrate concentrations were assigned by community; mothers’ overall intake of nitrate in mg/day from drinking water was calculated. Odds ratios for neural tube defects, limb deficiencies, oral cleft defects, and heart defects were estimated using mixed-effects models for logistic regression. Odds ratios (95% CIs) for the highest exposure group in offspring of mothers reporting exclusive use of bottled water were: neural tube defects [1.42 (0.51, 3.99)], limb deficiencies [1.86 (0.51, 6.80)], oral clefts [1.43 (0.61, 3.31)], and heart defects [2.13, (0.87, 5.17)]. Bottled water nitrate had no appreciable impact on risk for birth defects in the NBDPS. PMID:25473985

  13. Isotopic compositions of sulphates and nitrates from the Chilean nitrate deposits, evidence for concentration and fractionation of parental brines

    International Nuclear Information System (INIS)

    Isotopic compositions of nitrates (δ15N and δ18O) in caliche samples from the Chilean nitrate deposits are similar to recent values reported for nitrate associated to atmospheric N deposition. δ34S and δ18O of sulphate minerals present in the nitrate ores show similar values to those of continental evaporites in the area of Atacama, which suggest volcanic and hydrothermal sources. The sulphate isotope compositions display positive correlation trends (between δ34S and δ18OSO4) reflecting a reservoir effect due to fractionation related to precipitation. This effect has been clearly observed for sulphur and oxygen from sedimentary to bedrock caliche samples. Ore-grade bedrock caliche (mostly nitratine-halite mixtures filling veins) shows lower δ34S and δ18O values than sedimentary caliche (acting as wall rock). This suggests the concentration and fractionation of brines by repeated processes of evaporation and precipitation. Saline compounds of different origins present in the Neogene Atacama Desert were transported by the hydrological system towards the lower endorheic areas. As a result, saline minerals (mostly nitrates, chlorides and sulphates) precipitated filling the porosity and fractures of previous rocks (author)

  14. Distribution of Land Use to Purify Contaminated Groundwater by Nitrate

    Science.gov (United States)

    Iizumi, Y.; Tanaka, T.; Kinouchi, T.; Tase, N.; Fukami, K.

    2006-12-01

    Groundwater contamination by nitrate results from over-fertilizing and/or inadequate disposal of livestock excreta has been large-scale problem in agricultural area. Because nitrate is primarily transported to streams via ground water flow, explaining actual condition of groundwater is needed to propose an effective measure for the conservation and restoration of sound nitrogen cycle in agricultural river catchments. The purpose of this research was to clarify a triangular relationship between the groundwater quality and flow system, river water quality and land use. The experimental field is located on a slope from Tsukuba tableland to bottomland, which is a part of Nishi- Yata River watershed in Ibaraki Prefecture, Japan. The site area is about 0.0675 square kilometers and the altitude varies from 24 m to 19 m. Land use of tableland, bottomland and intermediate between them are forestland, paddy field and cropland, respectively. Groundwater quality and level were monitored for the year 2004. During the study period significant differences were not observed in groundwater ionic concentrations. Relative high concentrations of dissolved nitrate were detected in cropland (3 - 43 mg/l) and forestland (74 - 179 mg/l). It revealed that there was a purification zone in the paddy field and the area around its 2-4m and denitrification eliminates nitrate-nitrogen. The pressure head converted into hydraulics head, and the groundwater flow were calculated. According to the results, it seems that groundwater flow from tableland to the riverbed through bottomland. It is presumed that groundwater cultivated in cropland with chemical fertilizer pass through the purification zone of nitrate. On the other hand, it is assumed that groundwater containing nitrate originated from inadequate disposal of livestock excreta discharge from forestland does not pass through the depth of this spot. It is suggested that considering flow system of groundwater to manage distribution of land use

  15. Optimization of a uranyl nitrate passive neutron counter

    Energy Technology Data Exchange (ETDEWEB)

    Rauch, Eric Benton [Los Alamos National Laboratory; Bracken, David [Los Alamos National Laboratory; West, James [Los Alamos National Laboratory; Freeman, Corey [Los Alamos National Laboratory; Newell, Matthew R [Los Alamos National Laboratory; Bourret, Steven C [Los Alamos National Laboratory; Rothrock, Richard B [Los Alamos National Laboratory; Ladd - Lively, Jennifer L [ORNL; Schuh, Denise [ORNL

    2010-01-01

    Safeguarding natural uranium as it enters the fuel cycle has become a priority for the safeguards community in recent years. Uranyl nitrate is a material of interest in this endeavor because it is normally a step in the process from converting uranium ores to more concentrated forms like UO{sub 2} and U{sub 3}O{sub 8}. This paper will detail the improvements and design optimizations made for a uranyl nitrate neutron detector. The original design of the detector was based on standard neutron counter designs and featured 2 rings of He-3 tubes fully moderated and shielded from background. Several areas for enhancement were identified after months of testing in three different locations. An operating uranyl nitrate facility was included as one of the test locations. Three significant upgrades to the counter addressed in the redesign were: real time background detection, counter reliability improvements, and optimization of the detector design for the detection of neutrons emitted by the uranyl nitrate flowing through the monitored process pipe. The optimized detector design includes significant electronics upgrades, the ability to detect neutrons (background and signal) with 36 degree spatial resolution around the process pipe for signal and 45 degree spatial resolution for background, inner and outer rings of He-3 tubes for real time background corrections, and notably more reliable cabling. Monte Carlo N-Particle (MCNP) modeling was used to optimize the signal (neutrons from uranyl nitrate in the monitored process pipe) to noise (background neutrons from all sources) ratio of the inner ring of He-3 tubes. Additionally, MCNP modeling maximized noise to signal on the outer ring of He-3 tubes. Details of the detector optimization as well as all the additional detector enhancements will be discussed. The neutron counter will be field tested on the Uranyl Nitrate Calibration Loop Equipment (UNCLE) facility at Oak Ridge National Laboratory (ORNL).

  16. NAO-ocean circulation interactions in a coupled general circulation model

    Energy Technology Data Exchange (ETDEWEB)

    Bellucci, A. [Centro Euro-Mediterraneo per i Cambiamenti Climatici, Bologna (Italy); Gualdi, S.; Navarra, A. [Centro Euro-Mediterraneo per i Cambiamenti Climatici, Bologna (Italy); Istituto Nazionale di Geofisica e Vulcanologia, Bologna (Italy); Scoccimarro, E. [Istituto Nazionale di Geofisica e Vulcanologia, Bologna (Italy)

    2008-12-15

    The interplay between the North Atlantic Oscillation (NAO) and the large scale ocean circulation is inspected in a twentieth century simulation conducted with a state-of-the-art coupled general circulation model. Significant lead-lag covariance between oceanic and tropospheric variables suggests that the system supports a damped oscillatory mode involving an active ocean-atmosphere coupling, with a typical NAO-like space structure and a 5 years timescale, qualitatively consistent with a mid-latitude delayed oscillator paradigm. The two essential processes governing the oscillation are (1) a negative feedback between ocean gyre circulation and the high latitude SST meridional gradient and (2) a positive feedback between SST and the NAO. The atmospheric NAO pattern appears to have a weaker projection on the ocean meridional overturning, compared to the gyre circulation, which leads to a secondary role for the thermohaline circulation in driving the meridional heat transport, and thus the oscillatory mode. (orig.)

  17. Method of processing radioactive liquid waste containing soduium nitrate

    International Nuclear Information System (INIS)

    Sulfuric acid is added to radioactive liquid wastes containing sodium nitrate and heated to convert sodium nitrate into sodium sulfate and remove nitric acid as fumes. Then, calcium oxide or calcium hydroxide is added to the resultant liquid wastes containing sodium sulfate into a solution of calcium sulfate and sodium hydroxide. Then, solid-liquid separation is applied to take out, as a solid, calcium sulfate containing most portion of radioactive materials. Since no burnable materials such as asphalt are not used as in the prior art method, it is possible, according to the present invention, to reduce the fire hazard and remarkably decrease the formation of solidification products. (S.T.)

  18. Effect of vanadium on nitrate reductase activity in tomato leaves

    OpenAIRE

    J. Buczek

    2015-01-01

    The activity of nitrate reductase in cell-free extracts from tomato leaves is completely inhibited by 100 μM NaVO3 or VOCl2. In experiments in vivo vanadium ions inhibit the activity of the enzyme in 50 to 60 per cent. Addition of l mM vanadium to the medium on which tomato seedlings are grown causes after 24 h almost complete inhibition of nitrate reductase activity in cell-free extracts of the enzyme. Inhibition with vanadium may be abolished in experiments in vitro if the extract is treate...

  19. Transport of nitrate from a large cement based waste form

    International Nuclear Information System (INIS)

    A finite-element model is used to calculate the time-dependent transport of nitrate from a cement-based (saltstone) monolith with and without a clay cap. Model predictions agree well with data from two lysimeter field experiments begun in 1984. The clay cap effectively reduces the flux of nitrate from the monolith. Predictions for a landfill monolith design show a peak concentration occurring within 25 years; however, the drinking water guideline is exceeded for 1200 years. Alternate designs and various restrictive liners are being considered

  20. Conversion of uranium oxide into nitrate with nitrogen dioxide

    International Nuclear Information System (INIS)

    In order to decrease the amount of aqueous liquid waste discharged from nuclear fuel reprocessing, the conversion of uranium dioxide into its nitrate using liquefied nitrogen dioxide was studied. Uranium dioxide powder was immersed in liquefied nitrogen dioxide at 313 K after a pretreatment by the oxidation of the uranium dioxide with nitrogen dioxide and air at 523 K. Seventy-nine % of the uranium dioxide, whose initial feed amount was 0.3 g, was converted into a water soluble compound. Based on an XRD analysis, uranyl nitrate trihydrate (UO2(NO3)2)·3H2O) was confirmed as the product. (author)

  1. Estimated Dietary Intake of Nitrite and Nitrate in Swedish Children

    OpenAIRE

    Larsson, Kristin Anna; Darnerud, Per Ola; Ilbäck, Nils-Gunnar; Merino, Leonardo

    2011-01-01

    Abstract This study examined the intake of nitrate and nitrite in Swedish children. Daily intake estimates were based on a nationwide food consumption survey (4-day food diary) and nitrite/nitrate content in vegetables, fruit, cured meat and water. The mean intake of nitrite from cured meat among 2259 children studied was 0.013, 0.010 and 0.007 mg kg-1 body weight day-1 in age groups 4, 8-9 and 11-12, respectively. Among these age groups, three individuals (0.1% of the studied chil...

  2. Circulating Endothelial Microparticles in Diabetes Mellitus

    Directory of Open Access Journals (Sweden)

    A. F. Tramontano

    2010-01-01

    Full Text Available Background. Endothelial Microparticles (EMPs are small vesicles shed from activated or apoptotic endothelial cells and involved in cellular cross-talk. Whether EMP immunophenotypes vary according to stimulus in Diabetes Mellitus (DM is not known. We studied the cellular adhesion molecule (CAM profile of circulating EMPs in patients with and without Diabetes Mellitus type 2, who were undergoing elective cardiac catheterization. Methods and Results. EMPs were analyzed by flow cytometry. The absolute median number of EMPs (EMPs/L specific for CD31, CD105, and CD106 was significantly increased in the DM population. The ratio of CD62E/CD31 EMP populations reflected an apoptotic process. Conclusion. Circulating CD31+, CD105+, and CD106+ EMPs were significantly elevated in patients with DM. EMPs were the only independent predictors of DM in our study cohort. In addition, the EMP immunophenotype reflected an apoptotic process. Circulating EMPs may provide new options for risk assessment.

  3. Walker circulation in a transient climate

    Science.gov (United States)

    Plesca, Elina; Grützun, Verena; Buehler, Stefan A.

    2016-04-01

    The tropical overturning circulations modulate the heat exchange across the tropics and between the tropics and the poles. The anthropogenic influence on the climate system will affect these circulations, impacting the dynamics of the Earth system. In this work we focus on the Walker circulation. We investigate its temporal and spatial dynamical changes and their link to other climate features, such as surface and sea-surface temperature patterns, El-Niño Southern Oscillation (ENSO), and ocean heat-uptake, both at global and regional scale. In order to determine the impact of anthropogenic climate change on the tropical circulation, we analyze the outputs of 28 general circulation models (GCMs) from the CMIP5 project. We use the experiment with 1% year-1 increase in CO2 concentration from pre-industrial levels to quadrupling of the concentration. Consistent with previous studies (ex. Ma and Xie 2013), we find that for this experiment most GCMs associate a weakening Walker circulation to a warming transient climate. Due to the role of the Walker Pacific cell in the meridional heat and moisture transport across the tropical Pacific and also the connection to ENSO, we find that a weakened Walker circulation correlates with more extreme El-Niño events, although without a change in their frequency. The spatial analysis of the Pacific Walker cell suggests an eastward displacement of the ascending branch, which is consistent with positive SST anomalies over the tropical Pacific and the link of the Pacific Walker cell to ENSO. Recent studies (ex. England et al. 2014) have linked a strengthened Walker circulation to stronger ocean heat uptake, especially in the western Pacific. The inter-model comparison of the correlation between Walker circulation intensity and ocean heat uptake does not convey a robust response for the investigated experiment. However, there is some evidence that a stronger weakening of the Walker circulation is linked to a higher transient climate

  4. Tropical convective transport and the Walker circulation

    Directory of Open Access Journals (Sweden)

    J. S. Hosking

    2012-05-01

    Full Text Available We introduce a methodology to visualise rapid vertical and zonal tropical transport pathways. Using prescribed sea-surface temperatures in four monthly model integrations for 2005, preferred transport routes from the troposphere to the stratosphere are found in the model over the Maritime Continent (MC in November and February, i.e., boreal winter. In these months, the ascending branch of the Walker Circulation over the MC is formed in conjunction with strong deep convection, allowing fast transport into the stratosphere. At the same time, the downwelling branch of the Walker Circulation is enhanced over the East Pacific, compared to other months in 2005, reducing locally the upward transport from emissions below. We conclude that the Walker circulation plays an important role in the seasonality of fast tropical transport from the troposphere to the stratosphere and so impacts at the same time the potential supply of surface emissions.

  5. Experimental study of natural circulation circuit

    Energy Technology Data Exchange (ETDEWEB)

    Lemos, Wanderley F.; Su, Jian, E-mail: wlemos@lasme.coppe.ufrj.br, E-mail: sujian@lasme.coppe.ufrj.br [Coordenacao dos Programas de Pos-Graduacao de Engenharia (LASME/COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Lab. de Simulacao e Metodos Numericos; Faccini, Jose L.H., E-mail: faccini@ien.gov.br [Instituto de Engenharia Nuclear (LTE/IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil). Lab. de Termo-Hidraulica Experimental

    2011-07-01

    This work presents an experimental study about fluid flows behavior in natural circulation, under conditions of single-phase flow. The experiment was performed through experimental thermal-hydraulic circuit built at IEN. This test equipment has performance similar to passive system of residual heat removal present in Advanced Pressurized Water Reactors (APWR). This experimental study aims to observing and analyzing the natural circulation phenomenon, using this experimental circuit that was dimensioned and built based on concepts of similarity and scale. This philosophy allows the analysis of natural circulation behavior in single-phase flow conditions proportionally to the functioning real conditions of a nuclear reactor. The experiment was performed through procedures to initialization of hydraulic feeding of primary and secondary circuits and electrical energizing of resistors installed inside heater. Power controller has availability to adjust values of electrical power to feeding resistors, in order to portray several conditions of energy decay of nuclear reactor in a steady state. Data acquisition system allows the measurement and monitoring of the evolution of the temperature in various points through thermocouples installed in strategic points along hydraulic circuit. The behavior of the natural circulation phenomenon was monitored by graphical interface on computer screen, showing the temperature evolutions of measuring points and results stored in digital spreadsheets. The results stored in digital spreadsheets allowed the getting of data to graphic construction and discussion about natural circulation phenomenon. Finally, the calculus of Reynolds number allowed the establishment for a correlation of friction in function of geometric scales of length, heights and cross section of tubing, considering a natural circulation flow throughout in the region of hot leg. (author)

  6. First circulating beam in the AA

    CERN Multimedia

    1980-01-01

    On 3 July 1980, two years after project authorization, beam circulated for the first time in the AA. It was a 3.56 GeV/c proton test beam. We see an expecting crowd, minutes before the happy event. The persons are too numerous to name them all, but the 3 most prominent ones are at the centre (left to right): Roy Billinge (Joint AA Project Leader, with his hand on the control box), Eifionydd Jones (white shirt), Simon van der Meer (spiritus rector and Joint AA Project Leader). The first antiprotons were injected, made to circulate and cooled soon after, on 14 July 1980.

  7. Blowing Circulation Control on a Seaplane Airfoil

    Science.gov (United States)

    Guo, B. D.; Liu, P. Q.; Qu, Q. L.

    2011-09-01

    RANS simulations are presented for blowing circulation control on a seaplane airfoil. Realizable k-epsilon turbulent model and pressure-based coupled algorithm with second-order discretization were adopted to simulate the compressible flow. Both clear and simple flap configuration were simulated with blowing momentum coefficient Cμ = 0, 0.15 and 0.30. The results show that blowing near the airfoil trailing edge could enhance the Coanda effect, delay the flow separation, and increase the lift coefficient dramatically. The blowing circulation control is promising to apply to taking off and landing of an amphibious aircraft or seaplane.

  8. Quenching phenomena in natural circulation loop

    Energy Technology Data Exchange (ETDEWEB)

    Umekawa, Hisashi; Ozawa, Mamoru [Kansai Univ., Osaka (Japan); Ishida, Naoki [Daihatsu Motor Company, Osaka (Japan)

    1995-09-01

    Quenching phenomena has been investigated experimentally using circulation loop of liquid nitrogen. During the quenching under natural circulation, the heat transfer mode changes from film boiling to nucleate boiling, and at the same time flux changes with time depending on the vapor generation rate and related two-phase flow characteristics. Moreover, density wave oscillations occur under a certain operating condition, which is closely related to the dynamic behavior of the cooling curve. The experimental results indicates that the occurrence of the density wave oscillation induces the deterioration of effective cooling of the heat surface in the film and the transition boiling regions, which results in the decrease in the quenching velocity.

  9. Applications of Circulation Control, Yesterday and Today

    OpenAIRE

    Jonathan Kweder; Chad C. Panthe; James E. Smit

    2010-01-01

    Circulation control, an aerodynamic method of changing the properties of an airfoil, such as lift, camber and angle of attack, has been used in several unique ways since its inception, as an enhancement to fixed wing aircraft, in the 1960’s. Early in the research venture, this technology was used on the main wing of an aircraft in conjunction with a Coandă surface, such as a rounded trailing edge or a deployable flap. Research during this time proved to be the foundation of the circulation co...

  10. Applications of Circulation Control, Yesterday and Today

    Directory of Open Access Journals (Sweden)

    Jonathan Kweder

    2010-12-01

    Full Text Available Circulation control, an aerodynamic method of changing the properties of an airfoil, such as lift, camber and angle of attack, has been used in several unique ways since its inception, as an enhancement to fixed wing aircraft, in the 1960’s. Early in the research venture, this technology was used on the main wing of an aircraft in conjunction with a Coandă surface, such as a rounded trailing edge or a deployable flap. Research during this time proved to be the foundation of the circulation control technology and showed that small amounts of exit jet velocity could have a large impact on the aerodynamics of an airfoil. In the 1970’s the inspirations that drove circulation control research changed from design work to optimization of the parameters which were found to have the most effect on circulation control. These studies included slot placement, favorable momentum coefficient, and pressurization benefits and determents. This research period also allowed for expansion of the uses of circulation control to submarine/hydrodynamic and rotary wing applications. Newest research has brought on several propeller driven applications and the recent push for efficient renewable research has allowed circulation control research technologies to evolve into use in wind turbine and water turbine applications. The idea being that with circulation control the turbine can adapt easier to the changing wind velocity and direction and ultimately capture more power than an un-augmented turbine. As with most new and novel technologies there is a process and time delay associated with their development and ultimate application. For some technologies the market, or the supporting hardware, are lacking and sometimes the technology has strong advocacies for yet to be fulfilled expectations. In most of these cases a strong idea will re-surface repeatedly until the art has matured, or the better solution is found. This paper will focus on the previously developed

  11. Effect of nitrate, organic carbon, and temperature on potential denitrification rates in nitrate-rich riverbed sediments

    Science.gov (United States)

    Pfenning, K.S.; McMahon, P.B.

    1997-01-01

    A study conducted in 1994 as part of the US Geological Survey's National Water-Quality Assessment Program, South Platte River Basin investigation, examined the effect of certain environmental factors on potential denitrification rates in nitrate-rich riverbed sediments. The acetylene block technique was used to measure nitrous oxide (N2O) production rates in laboratory incubations of riverbed sediments to evaluate the effect of varying nitrate concentrations, organic carbon concentrations and type, and water temperature on potential denitrification rates. Sediment incubations amended with nitrate, at concentrations ranging from 357 to 2142 ??mol l-1 (as measured in the field), produced no significant increase (P > 0.05) in N2O production rates, indicating that the denitrification potential in these sediments was not nitrate limited. In contrast, incubations amended with acetate as a source of organic carbon, at concentrations ranging from 0 to 624 ??mol l-1, produced significant increases (P organic carbon concentration, indicating that the denitrification potential in these sediments was organic carbon limited. Furthermore, N2O production rates also were affected by the type of organic carbon available as an electron donor. Acetate and surface-water-derived fulvic acid supported higher N2O production rates than groundwater-derived fulvic acid or sedimentary organic carbon. Lowering incubation temperatures from 22 to 4??C resulted in about a 77% decrease in the N2O production rates. These results help to explain findings from previous studies indicating that only 15-30% of nitrate in groundwater was denitrified before discharging to the South Platte River and that nitrate concentrations in the river generally were higher in winter than in summer.

  12. Nitrate pollution and its distribution in the groundwater of Srikakulam district, Andhra Pradesh, India

    Science.gov (United States)

    Rao, Nagireddi Srinivasa

    2006-12-01

    The complex depositional pattern of clay and sand in most of the areas controlled the vertical and lateral movement of nitrate in groundwater. The variation of nitrate concentration at different groundwater levels and the lateral distribution of nitrate in the groundwater at two sites indicated the filtration of nitrate by clayey formations. A rural agricultural district located in the Vamsadhara river basin, India was selected for studying the lateral and vertical distribution of nitrate in the groundwater and the association of nitrate with other chemical constituents. The nitrate concentrations in the groundwater are observed to vary between below detectable limit and 450 mg NO3/L. The sources for nitrate are mainly point sources (poultry farms, cattleshed and leakages from septic tanks) and non-point sources (nitrogenous fertilisers). The nitrate concentrations are increased after fertiliser applications. However, very high concentrations of nitrate are derived from animal wastes. Relatively better correlations between nitrate and potassium are observed ( R = 0.74 to 0.82). The better relationship between these two chemical constituents in the groundwater may be due to the release of potassium and nitrate from both point and non-point sources. The nitrate and potassium concentrations are high in the groundwater from clayey formations.

  13. Uranous nitrate production for Purex process applications using PtO2 catalyst and hydrazine nitrate as reductant

    International Nuclear Information System (INIS)

    In spent fuel reprocessing by Purex process uranium and plutonium are extracted together in the solvent 30% TBP-dodecane to effect decontamination from fission products and trivalent actinides. In a subsequent partition step, uranium and plutonium are separated from each other by selectively reducing Pu(IV) to Pu(III) in which valency it is least extractable in the above solvent. The reduction of Pu(IV) to Pu(III) is accomplished with the reducing agent uranous nitrate, which is produced conventionally by electrolytic reduction of U(VI) with hydrazine nitrate as uranous nitrate stabilizer. In this method of reduction the percentage conversion attainable is only 50 to 60%. The use of this solution as partitioning agent leads not only to the dilution of the plutonium product but also to increase in uranium processing load by each externally fed uranous nitrate batch. Also the oxide coating of the anode, TSIA (Titanium Substrate Insoluble Anode) wears out after a certain period of operation. This necessitates recoating which is quite cumbersome considering the amount of the decontamination involved. So an alternative to the conventional electrolytic method has been explored in the laboratory at FRD. It is observed that quantitative reduction of uranyl nitrate to uranous nitrate can be achieved with hydrazine nitrate as reductant in presence of PtO2 catalyst. Extensive laboratory scale studies were carried out to optimize the various parameters for quantitative reduction. The optimum parameters for the reduction of 4 grams of uranyl ions as a single batch (20 ml) with a catalyst amount of 320 milligrams are H+ 1 M, N2H2+ = 1.0 M and temperature = 60 degC and the time for quantitative reduction under these optimized conditions was 60 minutes. These studies were then extended to pilot plant scale and the catalyst amount used in these in studies was 80 grams. When the column was operated under the optimized conditions, the uranous production per single batch (10 litres

  14. Influence of external circulation on sludge characteristics during start-up of internal circulation reactor

    Institute of Scientific and Technical Information of China (English)

    DING Jian-nan; WANG Dian-zuo

    2005-01-01

    The start-up of external circulation-added internal circulation(IC) reactor was finished in 26 d, 32 d fewer than that of IC reactor. To evaluate the influence of the added external circulation on the development of granular sludge, the characteristics of the granular sludge taken from the two tested laboratory-scale reactors during start-up were studied. The results show that the added external circulation can enhance biomass granulation, accelerate granule development and improve sludge characteristics. At the end of start-up, the granular size of sludge in external circulation-added IC reactor greatly increases with a size distribution much better than that of sludge in IC reactor. The granular sludge originated from external circulation-added IC reactor contains more extracellular polymers and has a greater settling velocity than that from IC reactor. Methanogenic activity of the granular sludge from the external circulation-added IC reactor started 26 d ago reaches 358.23 mL·g-1·d-1, 1.66 and 1.20 times as great as that of the sludge from the IC reactor started 26 d and 58 d ago respectively.

  15. Identification and structure of the nasR gene encoding a nitrate- and nitrite-responsive positive regulator of nasFEDCBA (nitrate assimilation) operon expression in Klebsiella pneumoniae M5al.

    OpenAIRE

    Goldman, B. S.; Lin, J. T.; Stewart, V

    1994-01-01

    Klebsiella pneumoniae can use nitrate and nitrite as sole nitrogen sources through the nitrate assimilatory pathway. The structural genes for assimilatory nitrate and nitrite reductases together with genes necessary for nitrate transport form an operon, nasFEDCBA. Expression of the nasF operon is regulated both by general nitrogen control and also by nitrate or nitrite induction. We have identified a gene, nasR, that is necessary for nitrate and nitrite induction. The nasR gene, located immed...

  16. Abuse of silver-nitrate solution for planing periorbital folds.

    Science.gov (United States)

    Schepler, Hadrian; Kessler, Jens; Hartmann, Bernd

    2002-02-01

    When using a Hollensteinstift to treat periorbital folds a 28-year-old female patient perceived a chemical burn of the lower lids and the periorbital regions. The initial treatment was frequent washing with soap solution and topical panthenol ointment. This unusual case is demonstrated to show the risks of improper use of silver-nitrate solution and to discuss therapeutic options. PMID:11834338

  17. Electrocatalytic reduction of nitrate and selenate by NapAB.

    Science.gov (United States)

    Gates, Andrew J; Butler, Clive S; Richardson, David J; Butt, Julea N

    2011-01-01

    Bacterial cellular metabolism is renowned for its metabolic diversity and adaptability. However, certain environments present particular challenges. Aerobic metabolism of highly reduced carbon substrates by soil bacteria such as Paracoccus pantotrophus presents one such challenge since it may result in excessive electron delivery to the respiratory redox chain when compared with the availability of terminal oxidant, O2. The level of a periplasmic ubiquinol-dependent nitrate reductase, NAP, is up-regulated in the presence of highly reduced carbon substrates. NAP oxidizes ubiquinol at the periplasmic face of the cytoplasmic membrane and reduces nitrate in the periplasm. Thus its activity counteracts the accumulation of excess reducing equivalents in ubiquinol, thereby maintaining the redox poise of the ubiquinone/ubiquinol pool without contributing to the protonmotive force across the cytoplasmic membrane. Although P. pantotrophus NapAB shows a high level of substrate specificity towards nitrate, the enzyme has also been reported to reduce selenate in spectrophotometric solution assays. This transaction draws on our current knowledge concerning the bacterial respiratory nitrate reductases and extends the application of PFE (protein film electrochemistry) to resolve and quantify the selenate reductase activity of NapAB. PMID:21265780

  18. electrocatalytic nitrate reduction on palladium based catalysts activated with germanium

    NARCIS (Netherlands)

    Gootzen, J.F.E.; Lefferts, L.; Veen, van J.A.R.

    1999-01-01

    The electrocatalytic reduction of nitrate has been studied with electrochemical methods on palladium and palladium–platinum electrodes activated with germanium. The formation of a palladium–germanium alloy that occurs at germanium coverage above 0.2 has a strong enhancing effect on the rate of nitra

  19. Improving N credit predictions to reduce residual nitrate

    Science.gov (United States)

    The potential to increase farm profitability and reduce nitrate leaching in Minnesota are huge if the alfalfa N credit was better understood and applied to first-year corn. If the N credit (150 lb/N/ac) were applied to the nearly 250,000 acres of corn following alfalfa in Minnesota each year, 19,000...

  20. Pollution par les nitrates: quels remèdes?

    OpenAIRE

    Zilliox, Lothaire; Schenck, Charles; Kobus, Helmut; Huwe, Bernd

    1990-01-01

    Au cours des dix dernières années, la pollution des eaux souterraines par les nitrates n'a cessé d'augmenter. Principale accussée: l'agriculture, l'application de méthodes de techniques culturales devrait permettre une meilleure gestion des engrais azotés.

  1. Role Playing and Mind Mapping Issues on Nitrate Contamination.

    Science.gov (United States)

    Pan, W. L.

    1996-01-01

    Presents mind-mapping and role-playing exercises designed to guide students in the exploration, expression, and integration of varying viewpoints and opinions of a controversial topic (nitrate contamination of water supply); illustrate the importance of applying soil fertility principles to environmental and agronomic management; and encourage…

  2. Denitrifying bioreactors for nitrate removal from tile drained cropland

    Science.gov (United States)

    Denitrification bioreactors are a promising technology for mitigation of nitrate-nitrogen (NO3-N) losses in subsurface drainage water. Bioreactors are constructed with carbon substrates, typically wood chips, to provide a substrate for denitrifying microorganisms. Researchers in Iowa found that for ...

  3. URBAN STREAM BURIAL INCREASES WATERSHED-SCALE NITRATE EXPORT

    Science.gov (United States)

    Nitrogen (N) uptake in streams is an important ecosystem service that may be affected by the widespread burial of streams in stormwater pipes in urban watersheds. We predicted that stream burial reduces the capacity of streams to remove nitrate (NO3-) from the water column by in...

  4. Radiation chemical dosimetry by means of nitrate-nitrite

    International Nuclear Information System (INIS)

    The different chemical systems used in dosimetry and the selection criteria for them are described. The general topics in dosimetry with alkali nitrates as well as the phenomena occurring in their radiolysis are also treated. The possibility of application in dosimetric areas useful in radiosterilization and industrial processes is studied too. (Author) 22 refs

  5. Nitrate Uptake into Barley (Hordeum vulgare) Plants 1

    Science.gov (United States)

    Deane-Drummond, Celia E.; Glass, Anthony D. M.

    1982-01-01

    Evidence is presented that chlorate is an extremely good analog for nitrate during nitrate uptake by intact barley (Hordeum vulgare cv. Fergus) roots. The depletion of ClO3− or NO3− from uptake media over 2 to 6 hours by seedlings was found to be dependent on combined NO3− plus ClO3− concentrations, and total anion uptake was equivalent at different NO3−/ClO3− ratios. After loading barley seedlings with 36ClO3− for 6 hours, kinetic parameters were derived from the analysis of efflux of [36Cl] chlorate into unlabeled solution. On the basis of this analysis, the half times for exchange for the cytoplasmic and vacuolar phases were 17 minutes and 20 hours, respectively. Data pooled from a number of different experiments were used to calculate kinetic constants (Km and Vmax) for 36ClO3− influx into barley roots at different external ClO3−/NO3− ratios, using short (10 minutes) influx times. There appeared to be no discrimination by the root cells between ClO3− and NO3−. Lineweaver-Burk analysis of the interaction between nitrate and chlorate were characteristic of competitive inhibition at low nitrate concentrations (0-0.5 mm). At higher concentrations, in the range of >1 mm, similar interactions between these ions were evident. PMID:16662478

  6. Bone and lung tumor response following inhalation of transuranic nitrates

    International Nuclear Information System (INIS)

    Eight-hundred five rats exposed to transuranic nitrate aerosols developed 111 lung tumors and 24 bone tumors. Results for 239Pu(NO3)4, 238Pu(NO3)4, and 253Es(NO3)3 were similar, and comparable to what has been shown for the more refractory transuranic oxides

  7. Identifying Efficient Nitrate Reduction Strategies in the Upper Danube

    Directory of Open Access Journals (Sweden)

    Angel Udias

    2016-08-01

    Full Text Available Nitrogen losses in the form of Nitrate (N-NO3 from point and diffuse sources of pollution are recognized to be the leading cause of water body impairment throughout Europe. Implementation of conservation programs is perceived as being crucial for restoring and protecting the good ecological status of freshwater bodies. The success of conservation programs depends on the efficient identification of management solutions with respect to the envisaged environmental and economic objectives. This is a complex task, especially considering that costs and effectiveness of conservation strategies depend on their locations. We applied a multi-objective, spatially explicit analysis tool, the R-SWAT-DM framework, to search for efficient, spatially-targeted solution of Nitrate abatement in the Upper Danube Basin. The Soil Water Assessment Tool (SWAT model served as the nonpoint source pollution estimator for current conditions as well as for scenarios with modified agricultural practices and waste water treatment upgrading. A spatially explicit optimization analysis that considered point and diffuse sources of Nitrate was performed to search for strategies that could achieve largest pollution abatement at minimum cost. The set of optimal spatial conservation strategies identified in the Basin indicated that it could be possible to reduce Nitrate loads by more than 50% while simultaneously provide a higher income.

  8. Aqueous Nitrate Recovery Line at Los Alamos National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Finstad, Casey Charles [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-06-15

    This powerpoint is part of the ADPSM Plutonium Engineering Lecture Series, which is an opportunity for new hires at LANL to get an overview of work done at TA55. It goes into detail about the aqueous nitrate recovery line at Los Alamos National Laboratory.

  9. Water flow and nitrate leaching in a layered silt loam

    NARCIS (Netherlands)

    Vos, J.A.; Hesterberg, D.L.R.; Raats, P.A.C.

    2000-01-01

    Nitrate (NO3) leaching was studied for a winter leaching period in a layered calcareous silt loam with tile-drains at about 1-m depth and 12-m spacing. Groundwater levels, drain discharge rates, and NO3 concentrations in the drainage water were monitored, and the soil hydraulic characteristics were

  10. Increase of water resistance of ammonium nitrate explosives

    Directory of Open Access Journals (Sweden)

    Zulkhair Mansurov

    2012-03-01

    Full Text Available Developed a method of kapsulating of ammonium nitrate with liquid paraffin increase finding explosives in water for 60 minutes. Placing explosives in the plastic shell, the explosive was, as in standing or running water during the day. When conducting field tests failures were absent.

  11. Profiling the origin of ammonium nitrate: proof-of-principle

    NARCIS (Netherlands)

    Carol-Visser, J.; Farmache, M.A.; Heijden, A.E.D.M. van der

    2011-01-01

    In many Improvised Explosive Devices (IEDs) the main charge consists of ammonium nitrate (AN). For forensic reasons, screening for the origin of AN is of importance. By assessing specifi c characteristics, diff erent AN batches can be profi led, in this way providing extra information which could le

  12. Nitrite-Responsive Activation of the Nitrate Assimilation Operon in Cyanobacteria Plays an Essential Role in Up-Regulation of Nitrate Assimilation Activities under Nitrate-Limited Growth Conditions

    OpenAIRE

    Aichi, Makiko; Maeda, Shin-Ichi; Ichikawa, Kazuhiro; Omata, Tatsuo

    2004-01-01

    NtcB of the cyanobacterium Synechococcus elongatus strain PCC 7942 is a LysR family protein that enhances expression of the nitrate assimilation operon (nirA operon) in response to the presence of nitrite, an intermediate of assimilatory nitrate reduction. Inactivation of ntcB in this cyanobacterium specifically abolishes the nitrite responsiveness of nirA operon expression, but under nitrate-replete conditions (wherein negative feedback by intracellularly generated ammonium prevails over the...

  13. Redefining circulating tumor cells by image processing

    NARCIS (Netherlands)

    Ligthart, S.T.

    2012-01-01

    Circulating tumor cells (CTC) in the blood of patients with metastatic carcinomas are associated with poor survival and can be used to guide therapy. However, CTC are very heterogeneous in size and shape, and are present at very low frequencies. Missing or misjudging a few events may have great cons

  14. On Pareto theory of circulation of elites

    OpenAIRE

    Ricardo P\\'erez-Marco

    2014-01-01

    We prove that Pareto theory of circulation of elites results from our wealth evolution model, Kelly criterion for optimal betting and Keynes' observation of "animal spirits" that drive the economy and cause that human financial decisions are prone to excess risk-taking.

  15. A Circulation Model for Busy Public Libraries.

    Science.gov (United States)

    Bagust, A.

    1983-01-01

    Develops stochastic model of library borrowing using Negative Binomial distribution applied to circulation data obtained from Huddersfield Public Library. Evidence concerning process of popularity decay is presented and method is given by which relegation tests can be constructed to maintain optimum turnover. Eight references and statistical…

  16. [Circulating "tumor markers" in gastrointestinal tumors].

    Science.gov (United States)

    Borlinghaus, P; Lamerz, R

    1991-09-01

    Tumor markers (TM) of the neoplastic cell can be divided into non-shedded substances and antigens shedded in blood, urine or other body fluids. For clinicians circulating TM are more important. All relevant circulating TM are not useful in screening of asymptomatic patients because of insufficient sensitivity and specificity. With caution they are useful in the observation of risk groups. Circulating TM have their main significance as additional parameters in monitoring symptomatic patients with malignancies. Several follow up determinations are more important than one single measurement. During follow up of tumor patients TM should not be checked automatically if there are no diagnostic or therapeutical consequences. The clinically most important circulating TM in non-hormone secreting tumors of the gastrointestinal tract are the oncofetal antigens CEA and AFP and antigens defined by monoclonal antibodies e. g. CA 19-9 and CA 72-4. AFP is the primary TM in hepatocellular carcinoma, often elevated in hepatoblastoma and always normal in cholangiocellular carcinoma. CEA is the TM of first choice in patients with colorectal carcinomas and liver metastasis. CA 19-9 is TM of first choice in pancreatic carcinoma and additionally of diagnostic value in cholangiocellular carcinoma and tumors of the bile ducts. In cancer of the stomach CA 19-9 and CEA are secondary TM in combination with CA 72-4 as primary TM. Care should be taken that slight and moderate elevations of TM can be observed in benign diseases of liver, pancreas and bowel.

  17. Detecting Holocene changes in thermohaline circulation

    OpenAIRE

    Keigwin, L. D.; Boyle, E.A.

    2000-01-01

    Throughout the last glacial cycle, reorganizations of deep ocean water masses were coincident with rapid millennial-scale changes in climate. Climate changes have been less severe during the present interglacial, but evidence for concurrent deep ocean circulation change is ambiguous.

  18. Detecting holocene changes in thermohaline circulation.

    Science.gov (United States)

    Keigwin, L D; Boyle, E A

    2000-02-15

    Throughout the last glacial cycle, reorganizations of deep ocean water masses were coincident with rapid millennial-scale changes in climate. Climate changes have been less severe during the present interglacial, but evidence for concurrent deep ocean circulation change is ambiguous. PMID:10677463

  19. Unsteady flow about a circulation control airfoil

    Institute of Scientific and Technical Information of China (English)

    刘晶昌; 孙茂; 吴礼义

    1996-01-01

    The unsteady flow around a circulation control (CC) airfoil was investigated with Navier-Stokes method,which includes the flow around CC airfoil with pulsating jet,the flow around oscillating CC airfoil,and the flow around oscillating CC airfoil with pulsating jet.Dynamic properties of the flow and the aerodynamic forces were rewaled.

  20. Ubiquity of organic nitrates from nighttime chemistry in the European submicron aerosol

    Science.gov (United States)

    Kiendler-Scharr, A.; Mensah, A. A.; Friese, E.; Topping, D.; Nemitz, E.; Prevot, A. S. H.; ńijälä, M.; Allan, J.; Canonaco, F.; Canagaratna, M.; Carbone, S.; Crippa, M.; Dall Osto, M.; Day, D. A.; De Carlo, P.; Di Marco, C. F.; Elbern, H.; Eriksson, A.; Freney, E.; Hao, L.; Herrmann, H.; Hildebrandt, L.; Hillamo, R.; Jimenez, J. L.; Laaksonen, A.; McFiggans, G.; Mohr, C.; O'Dowd, C.; Otjes, R.; Ovadnevaite, J.; Pandis, S. N.; Poulain, L.; Schlag, P.; Sellegri, K.; Swietlicki, E.; Tiitta, P.; Vermeulen, A.; Wahner, A.; Worsnop, D.; Wu, H.-C.

    2016-07-01

    In the atmosphere nighttime removal of volatile organic compounds is initiated to a large extent by reaction with the nitrate radical (NO3) forming organic nitrates which partition between gas and particulate phase. Here we show based on particle phase measurements performed at a suburban site in the Netherlands that organic nitrates contribute substantially to particulate nitrate and organic mass. Comparisons with a chemistry transport model indicate that most of the measured particulate organic nitrates are formed by NO3 oxidation. Using aerosol composition data from three intensive observation periods at numerous measurement sites across Europe, we conclude that organic nitrates are a considerable fraction of fine particulate matter (PM1) at the continental scale. Organic nitrates represent 34% to 44% of measured submicron aerosol nitrate and are found at all urban and rural sites, implying a substantial potential of PM reduction by NOx emission control.

  1. Development of a low cost, low environmental impact process for disposal of nitrate wastes

    International Nuclear Information System (INIS)

    A uranium recycle process in the Y-12 Plant generates nitrate ions which must be discarded. Scrap enriched uranium is dissolved in nitric acid and solvent extracted to remove impurities from the uranium. Aluminum nitrate is also used in the process to remove the purified uranium from the solvent extraction process. Dilute nitric acid, aluminum nitrate, and metallic impurities must be discarded from this process. A program was started to develop a low cost, low environmental impact process for disposal of these nitrate wastes. Several disposal methods were considered. A process was selected which included: distillation and recycle of nitric acid; crystallization and recycle of aluminum nitrate; and biodegradation of the remaining nitrate waste solutions. For this presentation, only the biodegradation process will be discussed. A colony of Pseudomonas stutzeri, which is capable of using the nitrate ion as the oxygen supply, was used. An excess of organic material was used to insure that the maximum amount of nitrate was destroyed

  2. Separation and recovery of sodium nitrate from low-level radioactive liquid waste by electrodialysis

    International Nuclear Information System (INIS)

    An advanced method, in which electrodialysis separation of sodium nitrate and decomposition of nitrate ion are combined, has been developed to remove nitrate ion from low-level radioactive liquid wastes including nitrate salts of high concentration. In the electrodialysis separation, the sodium nitrate was recovered as nitric acid and sodium hydroxide. When they are reused, it is necessary to reduce the quantity of impurities getting mixed with them from the waste fluid as much as possible. In this study, therefore, a cation exchange membrane with permselectivity for sodium ion and an anion exchange membrane with permselectivity for monovalent anion were employed. Using these membranes sodium and nitrate ions were effectively removed form a sodium nitrate solution of high concentration. And also it was confirmed that sodium ion was successfully separated from cesium and strontium ions and that nitrate ion was separated from sulfate and phosphate ions. (author)

  3. Influence of nitrate ions on the physicochemical behavior of neptunium

    International Nuclear Information System (INIS)

    The aim of this work was to acquire data on Np(VI) nitrate-complexes, particularly concerning their stability in nitric acid media, to gain a closer understanding of neptunium behavior in the PUREX process used for spent nuclear fuel reprocessing. Due to their very poor stability and the importance of physico-chemical mechanisms in concentrated solutions (media effects), the published data concerning these complexes are subject to considerable debate. A visible and near-infrared spectrophotometric study of Np(VI) nitrate-complexes was therefore undertaken to observe and quantify the influence of nitrate ions on the physicochemical behavior of neptunium, and to estimate the magnitude of the media effects in order to propose a constant of complexation by nitrate ions that is independent of the composition of the reaction medium (i.e. a thermodynamic constant). In the absence of reliable spectra for neptunium in nitric acid media, the spectrophotometric data were processed by principal components analysis and factor analysis mathematical method. The ionic strength of the solutions was adjusted by adding perchlorate salts (perchlorate ions were considered to have little or no complexing properties). The influence of the type of cation (H+, Li+, Na+, Ba2+, Mg2+) and the perchlorate ion concentration was observed on the neptunium(VI) spectra in nitric and perchloric media. In the presence of nitrate ions, the spectrum modifications in case of substitution of one cation by another were comparable to those observed for major nitrate ion concentration variations. Similarly, the extent of the spectrum modifications for the same nitrate ion concentration variation depended on the proton concentration. Weak spectrum modifications were also observed when the perchlorate ion concentration varied. They were quantified by a 'perturbation constant' β* calculated in the same way as a complexation constant (β* = 0.023 in the molal scale). To limit the disturbances responsible for

  4. Spectrophotometric study of neptunium (VI) complexation by nitrate ions

    International Nuclear Information System (INIS)

    Neptunium(VI) complexation by nitrate ions was investigated by visible and near-infrared spectrophotometry, a technique suitable for observing the appearance and evolution of the species in solution. In the absence of reference spectra for Np(VI) nitrate- complexes, mathematical (factor analysis) tools were used to interpret the spectra. These chemo-metric techniques were first tested and validated on a simpler chemical system: Np(VI)complexation by the SiW11O398- anion. The test media used to investigate Np(VI) nitrate- complexes generally contain nitrate and perchlorate salts at high concentrations (high ionic strength). Media effects arising from the presence of cations, acidity or the perchlorate ion concentration are therefore significant, and no doubt account for the scattered values of the complexation constants published in the literature. The evolution of the neptunium spectra according to the parameters of the reaction medium illustrated these effects and allowed them to be quantified by a global 'perturbation constant'. In order to minimize the spectrum modifications due to media effects, the neptunium nitrate-complexes were studied at constant ionic strength in weak acidic media (2 mol.kg-1H2O) in the presence of sodium salts. The bulk formation constants and the spectrum of the NpO2(NO3)+ complex were determined for ionic strength values of 2.2, 4, 6 and 8 mol.kg-1H2O. The constants remained on the same order of magnitude regardless of the ionic strength; the thermodynamic constant β10 determined from them according to specific interaction theory is thus probably of little significance. Conversely, the bulk constants can be corrected for the effects of the perchlorate ions by taking the global 'perturbation constant' into account. (author)

  5. Experimental evaluation of cement materials for solidifying sodium nitrate

    International Nuclear Information System (INIS)

    Low-level liquid waste containing sodium nitrate is planned to be transformed to salt block by evaporation with sodium borate in the Low-level Waste Treatment Facility (LWTF), then salt block will be stored temporally. It should be important to investigate the method how to treat these liquid waste suitable to final disposal criteria that will be settled in future. Cement solidification is one of promising candidates because it has been achieved as the solidification material for the shallow land disposal. The research was conducted to evaluate applicability of various cement materials to solidification of sodium nitrate. The following cements were tested. Ordinary Portland Cement (OPC). Portland Blast-furnace Slag Cement; C type (PBFSC). Alkali Activated Slag Cement (AASC, supplied by JGC). The test results are as follows; (1) AASC is characterized by a high sodium nitrate loading (-70 wt%) compared with other types of cement material. High fluidity of the cement paste, high strength after solidification, and minimization of free water on the cement paste are achieved under all test conditions. (2) OOPC and PBFSC produced free water on the cement paste in the early days and delayed the hardening period. 3 or more days are required to harden evan with 30 wt% content of sodium nitrate. (3) Though PBFSC contains blast furnace slag similar to AASC, there is no advantage prior to OPC. To design an ideal cement conditioning system for sodium nitrate liquid waste in the LWTF, the further studies are necessary such as the simulated waste test, Kd test, pilot test, and layout design. (author)

  6. Scaleable Nitrate Microsensors in the Form of a Plant Root

    Science.gov (United States)

    Harmon, T. C.; Jurisch, N. L.; Davidson, M. J.; Haux, J. E.

    2004-12-01

    This work describes the development of flexible, miniature and inexpensive nitrate sensors by electropolymerizing pyrrole onto carbon fiber substrates, using nitrate as a dopant. Carbon microfibers were found to be an excellent substitute to expensive conductive materials, such as glassy carbon or platinum. The electrodes with a 3-5 micron layer of NO3 -doped polypyrrole (PPy) exhibited a promising lifetime (at least 2 month without changes in sensitivity and linear response), fast response times (seconds), and sensitivity competitive to commercial nitrate ISE. Nernstian sensor response slopes of 54 to 58 mV/(decade concentration) for single filament have been observed, with a linear response to nitrate concentrations spanning three orders of magnitude (0.1 - 10-4 M or 6200 - 6.2 ppm of NO3-), and a detection limit of (3 ± 1) x 10-5 M (1.25-2.5 ppm). An advantage of using the carbon fibers as a substrate for pyrrole polymerization process is that these fibers are relatively easy to manipulate, lending themselves to root-like electrode designs which may be ideal for observing the water chemistry of soil moisture. Using prototypical PPy-coated microfibers, we have been able to directly measure nitrate concentrations in residual soil water contents as low as 8 percent by weight for a medium sand. Results for model soils and field samples are presented in which direct measurements with the microsensors compare reasonably well with a more conventional analytical method entailing soil extraction and analysis by the Griess-Romijn method.

  7. Circulation factors affecting precipitation over Bulgaria

    Science.gov (United States)

    Nojarov, Peter

    2015-09-01

    The objective of this paper is to determine the influence of circulation factors on precipitation in Bulgaria. The study succeeds investigation on the influence of circulation factors on air temperatures in Bulgaria, as the focus here is directed toward precipitation amounts. Circulation factors are represented through two circulation indices, showing west-east or south-north transport of air masses over Bulgaria and four teleconnection indices (patterns)—North Atlantic Oscillation, East Atlantic, East Atlantic/Western Russia, and Scandinavian. Omega values at 700-hPa level show vertical motions in the atmosphere. Annual precipitation trends are mixed and not statistically significant. A significant decrease of precipitation in Bulgaria is observed in November due to the strengthening of the eastward transport of air masses (strengthening of EA teleconnection pattern) and anticyclonal weather (increase of descending motions in the atmosphere). There is also a precipitation decrease in May and June due to the growing influence of the Azores High. An increase of precipitation happens in September. All this leads to a redistribution of annual precipitation course, but annual precipitation amounts remain the same. However, this redistribution has a negative impact on agriculture and winter ski tourism. Zonal circulation has a larger influence on precipitation in Bulgaria compared to meridional. Eastward transport throughout the year leads to lower than the normal precipitation, and vice versa. With regard to the four teleconnection patterns, winter precipitation in Bulgaria is determined mainly by EA/WR teleconnection pattern, spring and autumn by EA teleconnection pattern, and summer by SCAND teleconnection pattern.

  8. Decontamination of CAGR gas circulator components

    International Nuclear Information System (INIS)

    This paper describes the development and full-scale trial of two methods for removal of radioactive contamination on the surfaces of CAGR gas circulator components. The two methods described are a particle impact cleaning (PIC) decontamination technique and an electrochemical technique, 'electro-swabbing', which is based on the principle of decontamination by electro-polishing. In developing these techniques it was necessary to take account of the physical and chemical nature of the surface deposits on the gas circulator components; these were shown to consist of magnetite-type oxide and carbonaceous material. In order to follow the progress of the decontamination it was also necessary to develop a surface sampling technique which was effective and precise under these conditions; an electrochemical technique, employing similar principles to the electro-swabbing process, was developed for this purpose. The full-scale trial of the PIC decontamination technique was carried out on an inlet guide vane (IGV) assembly, this having been identified as the component from the gas circulator which contributes most to the radiation dose accumulated during routine circulator maintenance. The technique was shown to be practically viable and some 99% of the radioactive contamination was readily removed from the treated surfaces with only negligible surface damage being caused. The full-scale trial of the electro-swabbing decontamination technique was carried out on a gas circulator impeller. High decontamination factors were again achieved with ≥ 99% of the radioactive contamination being removed from the treated surfaces. The technique has practical limitations in terms of handling and treatment of waste-arisings. However, the use of specially-designed swabbing electrodes may allow the treatment of constricted geometries inaccessible to techniques such as PIC. The technique is also highly suitable for the treatment of soft-finish materials and of components fabricated from a

  9. Effects of Microtopography on Overmarsh Circulation

    Science.gov (United States)

    Sullivan, J. C.; Torres, R.; Garrett, A.

    2013-12-01

    Authors: J.C. Sullivan, R. Torres, A.J. Garrett In this study we systematically degrade a high-resolution, high precision salt marsh DEM and characterize the effects of DEM smoothing on overmarsh circulation. The question driving this effort is: How much topographic detail is needed to accurately simulate salt marsh circulation? The hydrodynamic model Delft3D was applied to data from a previous dye-tracer study in a 2 km2 semi-enclosed salt marsh basin at Skidaway Institute of Oceanography near Savannah, Georgia, USA. Overmarsh circulation was simulated for each smoothed DEM over a 5 day period corresponding to spring tide conditions. Results show that flood and ebb pathways differ significantly, but this effect is less apparent as the DEM is smoothed. Also, the flushing time (Tf) decreases with smoothing leading to greater dilution of a dye tracer with each tidal cycle. Observations at the macro, meso and micro scale show that flood and ebb flows become stronger through a consistent set of flow paths, including intertidal creeks, and differences in overmarsh circulation are more apparent in low marsh and channel head areas. This work shows that accurate representation of overmarsh circulation requires that the DEM resolve creek and low lying marsh structures at a spatial scale of 2-4m, but not necessarily the smallest tidal creeks (< 1m in width and depth). The next phase of this work will be to incorporate spatial variations in vegetation cover using RULLI (Remote Ultra Low-Light Imaging) remote sensing technology developed by the Department of Energy.

  10. Observations of the summer Red Sea circulation

    Science.gov (United States)

    Sofianos, Sarantis S.; Johns, William E.

    2007-06-01

    Aiming at exploring and understanding the summer circulation in the Red Sea, a cruise was conducted in the basin during the summer of 2001 involving hydrographic, meteorological, and direct current observations. The most prominent feature, characteristic of the summer circulation and exchange with the Indian Ocean, is a temperature, salinity, and oxygen minimum located around a depth of 75 m at the southern end of the basin, associated with Gulf of Aden Intermediate Water inflowing from the Gulf of Aden during the summer season as an intruding subsurface layer. Stirring and mixing with ambient waters lead to marked increases in temperature (from 16.5 to almost 33°C) and salinity (from 35.7 to more than 38 psu) in this layer by the time it reaches midbasin. The observed circulation presents a very vigorous pattern with strong variability and intense features that extend the width of the basin. A permanent cyclone, detected in the northern Red Sea, verifies previous observations and modeling studies, while in the central sector of the basin a series of very strong anticyclones were observed with maximum velocities exceeding 1 m/s. The three-layer flow pattern, representative of the summer exchange between the Red Sea and the Gulf of Aden, is observed in the strait of Bab el Mandeb. In the southern part of the basin the layer flow is characterized by strong banking of the inflows and outflows against the coasts. Both surface and intermediate water masses involved in the summer Red Sea circulation present prominent spatial variability in their characteristics, indicating that the eddy field and mixing processes play an important role in the summer Red Sea circulation.

  11. Nitrate groundwater pollution and aquifer vulnerability: the case of the Osona region

    OpenAIRE

    Boy Roura, Mercè

    2013-01-01

    Nitrate groundwater pollution in the Osona region is a persistent and widespread problem. Nitrate concentrations are commonly above the drinking water threshold of 50 mg/L in wells and springs. ANOVA and logistic regression analyses showed that nitrate concentration is more dependent on land use than on the geological setting of springs. Nitrate content presented stationary values in most of the springs over time, while discharge and electrical conductivity evolution depends on the geological...

  12. Nitrate absorption and strontium accumulation. Final report, 1 August 1973--31 December 1976

    International Nuclear Information System (INIS)

    Two basic objectives of this study to determine how strontium translocation, and discrimination between strontium and calcium in plants are influenced by nitrate uptake, assimilation, and translocation, and to characterize the relationships between nitrate uptake, nitrate assimilation, and nitrate translocation. Results are reported from studies using maize seedlings in which 85Sr and 45Ca were used as tracers. A list is included of publications that report the results of related studies

  13. Artificial electron donors for nitrate and nitrite reductases usable as mediators in amperometric biosensors

    Energy Technology Data Exchange (ETDEWEB)

    Strehlitz, B. (Umweltforschungszentrum Leipzig-Halle GmbH, Leipzig (Germany)); Gruendig, B. (Institut fuer Chemo- und Biosensorik, Muenster-Roxel (Germany)); Vorlop, K.D. (Bundesforschungsanstalt fuer Landwirtschaft, Braunschweig (Germany). Inst. fuer Technologie); Bartholmes, P. (Witten-Herdecke Univ., Witten (Germany). Inst. fuer Biochemie); Kotte, H. (Umweltforschungszentrum Leipzig-Halle GmbH, Leipzig (Germany)); Stottmeister, U. (Umweltforschungszentrum Leipzig-Halle GmbH, Leipzig (Germany))

    1994-07-01

    Various nitrate and nitrite reductases are capable of accepting electrons from artificial donors. Combining these redox active donors with an amperometric redox electrode which is covered with an immobilized layer of such a nitrate or nitrite reductase, new enzyme sensors can be created for the detection of nitrate or nitrite, respectively. A range of suitable electron donors for nitrate reductases and nitrite reductase from different sources have been selected and characterized by electrochemical methods. (orig.)

  14. Study on the nitrite and nitrate levels changes by drying and frying processing in vegetables

    OpenAIRE

    Sadeghi, E; K Sharafi; A Almasi; M Dayhim; E Azizi; M Ghayebzadeh

    2014-01-01

    Background and objectives: Nitrate and nitrite threaten the human health. According to recent research works, one of the great sources of exposure to nitrate and nitrite in human diet is vegetables. The aim of this study is to determine the effect of drying and frying processes on nitrate and nitrite levels in abundant vegetables. Materials and methods: In this descriptive – analytical study, 180 vegetable samples were taken randomly from Kermanshah markets. Nitrite and nitrate concentrati...

  15. Soil nitrate reducing processes – drivers, mechanisms for spatial variation, and significance for nitrous oxide production

    OpenAIRE

    Giles, Madeline; Morley, Nicholas; Baggs, Elizabeth M; Daniell, Tim J.

    2012-01-01

    The microbial processes of denitrification and dissimilatory nitrate reduction to ammonium (DNRA) are two important nitrate reducing mechanisms in soil, which are responsible for the loss of nitrate ( NO 3 − ) and production of the potent greenhouse gas, nitrous oxide (N2O). A number of factors are known to control these processes, including O2 concentrations and moisture content, N, C, pH, and the size and community structure of nitrate reducing organisms responsible for the processes. There...

  16. Soil nitrate reducing processes – drivers, mechanisms for spatial variation and significance for nitrous oxide production

    OpenAIRE

    TimJohnDaniell; MadelineEleanoreGiles

    2012-01-01

    The microbial processes of denitrification and dissimilatory nitrate reduction to ammonium (DNRA) are two important nitrate reducing mechanisms in soil, which are responsible for the loss of nitrate (NO3-¬) and production of the potent greenhouse gas, nitrous oxide (N2O). A number of factors are known to control these processes, including O2 concentrations and moisture content, N, C, pH and the size and community structure of nitrate reducing organisms responsible for the processes. Ther...

  17. Nitrate Enhanced Microbial Cr(VI) Reduction-Final Report

    Energy Technology Data Exchange (ETDEWEB)

    John F. Stolz

    2011-06-15

    A major challenge for the bioremediation of radionuclides (i.e., uranium, technetium) and metals (i.e., Cr(VI), Hg) is the co-occurrence of nitrate as it can inhibit metal transformation. Denitrification (nitrate reduction to dinitrogen gas) is considered the most important ecological process. For many metal and metalloid reducing bacteria, however, ammonia is the end product through respiratory nitrate reduction (RNRA). The focus of this work was to determine how RNRA impacts Cr(VI) transformation. The goal was to elucidate the specific mechanism(s) that limits Cr(VI) reduction in the presence of nitrate and to use this information to develop strategies that enhance Cr(VI) reduction (and thus detoxification). Our central hypothesis is that nitrate impacts the biotransformation of metals and metalloids in three ways 1) as a competitive alternative electron acceptor (inhibiting transformation), 2) as a co-metabolite (i.e., concomitant reduction, stimulating transformation), and 3) as an inducer of specific proteins and pathways involved in oxidation/reduction reactions (stimulating transformation). We have identified three model organisms, Geobacter metallireducens (mechanism 1), Sulfurospirillum barnesii, (mechasism 2), and Desulfovibrio desulfuricans (mechanisms 3). Our specific aims were to 1) investigate the role of Cr(VI) concentration on the kinetics of both growth and reduction of nitrate, nitrite, and Cr(VI) in these three organisms; 2) develop a profile of bacterial enzymes involved in nitrate transformation (e.g., oxidoreductases) using a proteomic approach; 3) investigate the function of periplasmic nitrite reductase (Nrf) as a chromate reductase; and 4) develop a strategy to maximize microbial chromium reduction in the presence of nitrate. We found that growth on nitrate by G. metallireducens was inhibited by Cr(VI). Over 240 proteins were identified by LC/MS-MS. Redox active proteins, outer membrane heavy metal efflux proteins, and chemotaxis sensory

  18. Development Strategies for Rural Key Circulation Service Network

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    The rural key circulation service network is an important channel for ensuring agricultural products’entry to market and urban industrial products’entry to rural areas.Through in-depth survey and research,we took a look at development changes and current situations of three circulation service networks,namely,circulation of nondurable consumer goods,circulation of agricultural means of production,and circulation of agricultural products.Based on several key problems in rural circulation service network,such as logistics problem,delivery problem,backward transaction mode,and the last kilometer information,we put forward corresponding development countermeasures.

  19. Identification and quantification of a novel nitrate-reducing community in sediments of Suquia River basin along a nitrate gradient

    Energy Technology Data Exchange (ETDEWEB)

    Reyna, Luciana; Wunderlin, Daniel Alberto [Universidad Nacional de Cordoba-CONICET, Facultad de Ciencias Quimicas, Departamento de Bioquimica Clinica-CIBICI, Haya de la Torre y Medina Allende, Ciudad Universitaria, 5000 Cordoba (Argentina); Genti-Raimondi, Susana, E-mail: sgenti@fcq.unc.edu.a [Universidad Nacional de Cordoba-CONICET, Facultad de Ciencias Quimicas, Departamento de Bioquimica Clinica-CIBICI, Haya de la Torre y Medina Allende, Ciudad Universitaria, 5000 Cordoba (Argentina)

    2010-05-15

    We evaluated the molecular diversity of narG gene from Suquia River sediments to assess the impact of the nitrate concentration and water quality on the composition and structure of the nitrate-reducing bacterial community. To this aim, a library of one of the six monitoring stations corresponding to the highest nitrate concentration was constructed and 118 narG clones were screened. Nucleotide sequences were associated to narG gene from alpha-, beta-, delta-, gammaproteobacteria and Thermus thermophilus. Remarkably, 18% of clones contained narG genes with less than 69% similarity to narG sequences available in databases. Thus, indicating the presence of nitrate-reducing bacteria with novel narG genes, which were quantified by real-time PCR. Results show a variable number of narG copies, ranging from less than 1.0 x 10{sup 2} to 5.0 x 10{sup 4} copies per ng of DNA, which were associated with a decreased water quality index monitored along the basin at different times. - A novel narG community present in Suquia River sediments was quantified; values were in line with the water quality index.

  20. The histone deacetylase inhibitor SAHA induces HSP60 nitration and its extracellular release by exosomal vesicles in human lung-derived carcinoma cells.

    Science.gov (United States)

    Campanella, Claudia; D'Anneo, Antonella; Marino Gammazza, Antonella; Caruso Bavisotto, Celeste; Barone, Rosario; Emanuele, Sonia; Lo Cascio, Filippa; Mocciaro, Emanuele; Fais, Stefano; Conway De Macario, Everly; Macario, Alberto J L; Cappello, Francesco; Lauricella, Marianna

    2016-05-17

    HSP60 undergoes changes in quantity and distribution in some types of tumors suggesting a participation of the chaperonin in the mechanism of transformation and cancer progression. Suberoylanilide hydroxamic acid (SAHA), a member of a family of histone deacetylase inhibitors (HDACi), has anti-cancer potential but its interaction, if any, with HSP60 has not been elucidated. We investigated the effects of SAHA in a human lung-derived carcinoma cell line (H292). We analysed cell viability and cycle; oxidative stress markers; mitochondrial integrity; HSP60 protein and mRNA levels; and HSP60 post-translational modifications, and its secretion. We found that SAHA is cytotoxic for H292 cells, interrupting the cycle at the G2/M phase, which is followed by death; cytotoxicity is associated with oxidative stress, mitochondrial damage, and diminution of intracellular levels of HSP60; HSP60 undergoes a post-translational modification and becomes nitrated; and nitrated HSP60 is exported via exosomes. We propose that SAHA causes ROS overproduction and mitochondrial dysfunction, which leads to HSP60 nitration and release into the intercellular space and circulation to interact with the immune system. These successive steps might constitute the mechanism of the anti-tumor action of SAHA and provide a basis to design supplementary therapeutic strategies targeting HSP60, which would be more efficacious than the compound alone.

  1. Nitrate sensing by the maize root apex transition zone: a merged transcriptomic and proteomic survey.

    Science.gov (United States)

    Trevisan, Sara; Manoli, Alessandro; Ravazzolo, Laura; Botton, Alessandro; Pivato, Micaela; Masi, Antonio; Quaggiotti, Silvia

    2015-07-01

    Nitrate is an essential nutrient for plants, and crops depend on its availability for growth and development, but its presence in agricultural soils is far from stable. In order to overcome nitrate fluctuations in soil, plants have developed adaptive mechanisms allowing them to grow despite changes in external nitrate availability. Nitrate can act as both nutrient and signal, regulating global gene expression in plants, and the root tip has been proposed as the sensory organ. A set of genome-wide studies has demonstrated several nitrate-regulated genes in the roots of many plants, although only a few studies have been carried out on distinct root zones. To unravel new details of the transcriptomic and proteomic responses to nitrate availability in a major food crop, a double untargeted approach was conducted on a transition zone-enriched root portion of maize seedlings subjected to differing nitrate supplies. The results highlighted a complex transcriptomic and proteomic reprogramming that occurs in response to nitrate, emphasizing the role of this root zone in sensing and transducing nitrate signal. Our findings indicated a relationship of nitrate with biosynthesis and signalling of several phytohormones, such as auxin, strigolactones, and brassinosteroids. Moreover, the already hypothesized involvement of nitric oxide in the early response to nitrate was confirmed with the use of nitric oxide inhibitors. Our results also suggested that cytoskeleton activation and cell wall modification occurred in response to nitrate provision in the transition zone.

  2. 76 FR 49449 - Continuation of Antidumping Duty Order on Solid Fertilizer Grade Ammonium Nitrate From the...

    Science.gov (United States)

    2011-08-10

    ... International Trade Administration Continuation of Antidumping Duty Order on Solid Fertilizer Grade Ammonium... duty investigation on solid fertilizer grade ammonium nitrate (``ammonium nitrate'') from the Russian... Initiation of Five-Year (``Sunset'') Review, 76 FR 11202 (March 1, 2011) and Ammonium Nitrate from...

  3. 76 FR 39847 - Solid Fertilizer Grade Ammonium Nitrate From the Russian Federation; Final Results of the...

    Science.gov (United States)

    2011-07-07

    ...: Solid Fertilizer Grade Ammonium Nitrate From the Russian Federation, 64 FR 45236 (August 19, 1999). On... Fertilizer Grade Ammonium Nitrate From the Russian Federation, 65 FR 42669 (July 11, 2000) (``Final... International Trade Administration Solid Fertilizer Grade Ammonium Nitrate From the Russian Federation;...

  4. Leaching of nitrate from agriculture to groundwater: the effect of policies and measures in the Netherlands

    NARCIS (Netherlands)

    Oenema, O.; Boers, P.C.M.; Eerdt, van M.M.; Fraters, B.; Meer, van der H.G.; Roest, C.W.J.; Schröder, J.J.; Willems, W.J.

    1998-01-01

    Nitrate concentrations in groundwater are correlated with the nitrogen surpluses at the soil surface. In the Netherlands, both nitrogen surpluses of agricultural land and nitrate concentrations in the groundwater of sandy soils are high. At present, nitrate concentrations in the groundwater of sandy

  5. A Convenient Method for Preparation of Pure Standards of Peroxyacetyl Nitrate for Atmospheric Analyses

    DEFF Research Database (Denmark)

    Nielsen, Torben; Hansen, A. M.; Lund Thomsen, E.

    1982-01-01

    Peroxyacetyl nitrate (PAN) is synthesized by nitration of peracetic acid (1.2 M), extracted by n- heptane, and purified with normal-phase high-performance liquid chromatography. The purified PAN solution is free of acetyl nitrate. The content of PAN is determined by means of hydrolysis of PAN int...

  6. 75 FR 29534 - Inorganic Nitrates-Nitrite, Carbon and Carbon Dioxide, and Sulfur Registration Review; Draft...

    Science.gov (United States)

    2010-05-26

    ... AGENCY Inorganic Nitrates-Nitrite, Carbon and Carbon Dioxide, and Sulfur Registration Review; Draft... draft ecological risk assessment for the registration review of inorganic nitrates - nitrites, carbon... occur for all inorganic nitrates- nitrites, carbon and carbon dioxide uses, as well as gas...

  7. Combined ion exchange/biological denitrification for nitrate removal from ground water.

    NARCIS (Netherlands)

    Hoek, van der J.P.

    1988-01-01

    This thesis deals with the development of a new process for nitrate removal from ground water. High nitrate concentrations in ground water are a result of fertilization in agriculture. According to a directive of the European Community the maximum admissible concentration of nitrate in drinking wate

  8. Nitrate retention in riparian ground water at natural and elevated nitrate levels in North Central Minnesota

    Science.gov (United States)

    Duff, J.H.; Jackman, A.P.; Triska, F.J.; Sheibley, R.W.; Avanzino, R.J.

    2007-01-01

    The relationship between local ground water flows and NO3- transport to the channel was examined in three well transects from a natural, wooded riparian zone adjacent to the Shingobee River, MN. The hillslope ground water originated as recharge from intermittently grazed pasture up slope of the site. In the hillslope transect perpendicular to the stream, ground water NO3- concentrations decreased from ???3 mg N L-1 beneath the ridge (80 m from the channel) to 0.01 to 1.0 mg N L-1 at wells 1 to 3 m from the channel. The Cl- concentrations and NO3/Cl ratios decreased toward the channel indicating NO3- dilution and biotic retention. In the bankside well transect parallel to the stream, two distinct ground water environments were observed: an alluvial environment upstream of a relict beaver dam influenced by stream water and a hillslope environment downstream of the relict beaver dam. Nitrate was elevated to levels representative of agricultural runoff in a third well transect looted ???5 m from the stream to assess the effectiveness of the riparian zone as a NO3- sink. Subsurface NO3- injections revealed transport of up to 15 mg N L-1 was nearly conservative in the alluvial riparian environment. Addition of glucose stimulated dissolved oxygen uptake and promoted NO3- retention under both background and elevated NO 3- levels in summer and winter. Disappearance of added NO3- was followed by transient NO2- formation and, in the presence of C2H2, by N2O formation, demonstrating potential denitrification. Under current land use, most NO3- associated with local ground water is biotically retained or diluted before reaching the channel. However, elevating NO 3- levels through agricultural cultivation would likely result in increased NO3- transport to the channel. ?? ASA, CSSA, SSSA.

  9. Effect of nitrate on activities and transcript levels of nitrate reductase and glutamine synthetase in rice

    Institute of Scientific and Technical Information of China (English)

    CAO Yun; FAN Xiao-Rong; SUN Shu-Bin; XU Guo-Hua; HU Jiang; SHEN Qi-Rong

    2008-01-01

    Real-time polymerase chain reaction analysis was used to compare the effect of NO-3 on the activities of nitrate reductase (NR) and glutamine synthetase (GS),and the transcript levels of two NR genes,OsNia1 and OsNia2,two cytceolic GS1 genes,OsGln1;1 and OsGln1;2,and one plastid GS2 gene OsGln2,in two rice (Oryza sativa L.) cultivars Nanguang (NG) and Yunjing (YJ).Both cultivars achieved greater biomass and higher total N concentration when grown in a mixed N supply than in sole NH+ nutrition.Supply of NO-3 increased NR activity in both leaves and roots.Expression of both NR genes was also substantially enhanced and transcript levels of OsNia2 were significantly higher than those of OsNia1.NO-3 also caused an increase in GS activity,but had a complex effect on the expression of the three GS genes.In roots,the OsGln1;1 transcript increased,but OsGln1;2 decreased.In leaves,NO-3 had no effect on the GS1 expression,but the transcript for OsGln2 increased both in the leaves and roots of rice with a mixed supply of N.These results suggested that the increase in GS activity might be a result of the complicated regulation of the various GS genes.In addition,the NO-3 induced increase of biomass,NR activity,GS activity,and the transcript levels of NR and GS genes were proportionally higher in NG than in YJ,indicating a stronger response of NG to NO-3 nutrition than YJ.

  10. Comparative induction of nitrate reductase by nitrate and nitrite in barley leaves

    Science.gov (United States)

    Aslam, M.; Rosichan, J. L.; Huffaker, R. C.

    1987-01-01

    The comparative induction of nitrate reductase (NR) by ambient NO3- and NO2- as a function of influx, reduction (as NR was induced) and accumulation in detached leaves of 8-day-old barley (Hordeum vulgare L.) seedlings was determined. The dynamic interaction of NO3- influx, reduction and accumulation on NR induction was shown. The activity of NR, as it was induced, influenced its further induction by affecting the internal concentration of NO3-. As the ambient concentration of NO3- increased, the relative influences imposed by influx and reduction on NO3- accumulation changed with influx becoming a more predominant regulant. Significant levels of NO3- accumulated in NO2(-)-fed leaves. When the leaves were supplied cycloheximide or tungstate along with NO2-, about 60% more NO3- accumulated in the leaves than in the absence of the inhibitors. In NO3(-)-supplied leaves NR induction was observed at an ambient concentration of as low as 0.02 mM. No NR induction occurred in leaves supplied with NO2- until the ambient NO2- concentration was 0.5 mM. In fact, NR induction from NO2- solutions was not seen until NO3- was detected in the leaves. The amount of NO3- accumulating in NO2(-)-fed leaves induced similar levels of NR as did equivalent amounts of NO3- accumulating from NO3(-)-fed leaves. In all cases the internal concentration of NO3-, but not NO2-, was highly correlated with the amount of NR induced. The evidence indicated that NO3- was a more likely inducer of NR than was NO2-.

  11. Organic Nitrates and Nitrate Resistance in Diabetes: The Role of Vascular Dysfunction and Oxidative Stress with Emphasis on Antioxidant Properties of Pentaerithrityl Tetranitrate

    Directory of Open Access Journals (Sweden)

    Matthias Oelze

    2010-01-01

    Full Text Available Organic nitrates represent a class of drugs which are clinically used for treatment of ischemic symptoms of angina as well as for congestive heart failure based on the idea to overcome the impaired NO bioavailability by “NO” replacement therapy. The present paper is focused on parallels between diabetes mellitus and nitrate tolerance, and aims to discuss the mechanisms underlying nitrate resistance in the setting of diabetes. Since oxidative stress was identified as an important factor in the development of tolerance to organic nitrates, but also represents a hallmark of diabetic complications, this may represent a common principle for both disorders where therapeutic intervention should start. This paper examines the evidence supporting the hypothesis that pentaerithrityl tetranitrate may represent a nitrate for treatment of ischemia in diabetic patients. This evidence is based on the considerations of parallels between diabetes mellitus and nitrate tolerance as well as on preliminary data from experimental diabetes studies.

  12. Warm World Ocean Thermohaline Circulation Model

    Science.gov (United States)

    Zimov, N.; Zimov, S. A.

    2014-12-01

    Modern day ocean circulation is dominated by thermal convection with cold waters subsiding in the Northern Atlantic, filling the ocean interior with cold and heavy water. However, ocean circulation diminished during the last glaciation and consequently the downwelling of the cold. Therefore interior ocean water temperatures must have been affected by other mechanisms which are negligible in the current state. We propose that the submergence of highly saline water from warm seas with high rates of evaporation (like the Red or Mediterranean Sea) was a major factor controlling ocean circulation during the last glaciation. Even today, waters in these poorly connected seas are the heaviest waters in the World ocean (1.029 g/cm3). The second mechanism affecting ocean temperature is the geothermal heat flux. With no heat exchange between the atmosphere and the ocean, geothermal heat flux through the ocean floor is capable of increasing ocean temperature by tens of degrees C over a 100 thousand year glacial cycle. To support these hypotheses we present an ocean box model that describes thermohaline circulation in the World Ocean. According to the model parameters, all water circulation is driven by the water density gradient. Boxes include high-latitude seas, high salinity seas, surface ocean, glaciers, and rift and lateral zones of the ocean interior. External heat sources are radiative forcing, affected by Milankovich cycles, and geothermal heat flux. Additionally this model accounts for the heat produced by organic rain decay. Taking all input parameters close to currently observed values, the model manages to recreate the glacial-interglacial cycles. During the glacial periods only haline circulation takes place, the ocean is strongly stratified, and the interior ocean accumulates heat while high-latitudes accumulate ice. 112,000 years after glaciation starts, water density on the ocean bottom becomes equal to the density of water in high-latitude seas, strong thermal

  13. Nitrate and nitrite-mediated transcription antitermination control of nasF (nitrate assimilation) operon expression in Klebsiella pheumoniae M5al.

    Science.gov (United States)

    Lin, J T; Stewart, V

    1996-03-01

    Klebsiella pneumoniae can use nitrate and nitrite as sole nitrogen sources during aerobic growth. Nitrate is converted through nitrite to ammonium by assimilatory nitrate and nitrite reductase, respectively. Enzymes required for nitrate assimilation are encoded by the nasFEDCBA operon of K. pneumoniae; nasF operon expression is subject to both general nitrogen control and pathway-specific nitrate/nitrite induction, mediated by the NtrC and NasR proteins, respectively. Sequence inspection revealed a presumptive sigmaN (sigma54)-dependent promoter as well as two presumptive upstream NtrC protein binding sites. Site-specific mutational and primer extension analyses confirmed the identity of the sigmaN-dependent promoter. Deletions removing the apparent NtrC protein binding sites greatly reduced NtrC-dependent regulation, indicating that these sites are involved in general nitrogen control. However, deletions removing most of the sequence upstream of the promoter had little effect on nitrate/nitrite regulation, suggesting that the nasF leader region is involved in nitrate/nitrite regulation. The 119 nucleotide long transcribed leader region contains an apparent factor-independent transcription terminator. Promoter replacement experiments demonstrated that the leader region is involved in nitrate/nitrite regulation of nasF operon expression. Deletions removing the transcription terminator structure resulted in a nitrate-blind constitutive phenotype, indicating that the transcription terminator structure serves a negative function. Other deletions, removing proximal portions of the leader region, resulted in an uninducible phenotype, indicating that this region serves a positive function. These results indicate that nitrate/nitrite regulation of nasF operon expression is determined by a transcription attenuation mechanism. We hypothesize that in the absence of nitrate or nitrite, the terminator structure abrogates transcription readthrough into the nasF operon. In the

  14. Silent Circulation of Ross River Virus in French Polynesia

    Directory of Open Access Journals (Sweden)

    Maite Aubry

    2015-08-01

    Discussion: Our results support the existence of autochthonous RRV transmission and suggest that this pathogen has silently circulated in French Polynesia. These findings raise the question of possible undetected circulation of RRV in other Pacific Island Countries and Territories.

  15. Anti-cyclonic circulation driven by the estuarine circulation in a gulf type ROFI

    Science.gov (United States)

    Fujiwara, T.; Sanford, L. P.; Nakatsuji, K.; Sugiyama, Y.

    1997-08-01

    Baroclinic residual circulation processes are examined in gulf type Regions Of Freshwater Influence (ROFIs), which have large rivers discharging into a rounded head wider than the Rossby internal deformation radius. Theoretical and observational investigations concentrate on Ise Bay, Japan, with supporting data from Osaka Bay and Tokyo Bay. Simplified analytical solutions are derived to describe the primary features of the circulation. Three dimensional residual current data collected using moored current meters and shipboard acoustic doppler current profilers (ADCPs), satellite imagery and density structure data observed using STDs, are presented for comparison to the theoretical predictions. There are three key points to understanding the resulting circulation in gulf type ROFIs. First, there are likely to be three distinct water masses: the river plume, a brackish upper layer, and a higher salinity lower layer. Second, baroclinic processes in gulf type ROFIs are influenced by the Earth's rotation at first order. Residual currents are quasi-geostrophic and potential vorticity is approximately conserved. Third, the combined effects of a classical longitudinal estuarine circulation and the Earth's rotation are both necessary to produce the resulting circulation. Anti-cyclonic vorticity is generated in the upper layer by the horizontal divergence associated with upward entrainment, which is part of the estuarine circulation. The interaction between anti-cyclonic vorticity and horizontal divergence results in two regions of qualitatively different circulation, with gyre-like circulation near the bay head and uniformly seaward anti-cyclonicly sheared flow further towards the mouth. The stagnation point separating the two regions is closer to (further away from) the bay head for stronger (weaker) horizontal divergence, respectively. The vorticity and spin-up time of this circulation are-(ƒ-ω 1)/2 and h/2w 0, respectively, where ƒ is the Coriolis parameter, ω 1 is

  16. Observations of total peroxy nitrates and total alkyl nitrates during the OP3 campaign: isoprene nitrate chemistry above a south-east Asian tropical rain forest

    Directory of Open Access Journals (Sweden)

    E. Aruffo

    2012-02-01

    Full Text Available Measurements of total peroxy nitrates (ΣRO2NO2, ΣPNs, total alkyl nitrates (ΣRONO2, ΣANs and nitrogen dioxide (NO2 were made above the surface of a Malaysian tropical rain forest in Borneo, using a laser-induced fluorescence instrument developed at the University of L'Aquila (Italy. This new instrument uses the direct excitation of NO2 at 532 nm in order to measure its concentrations detecting by the NO2 fluorescence at wavelengths longer than 610 nm. ΣPNs and ΣANs are indirectly measured after their thermal dissociation into NO2. Observations showed enhanced levels of NO2 during nighttime, an increase of ΣPNs during the afternoon and almost no evident diurnal cycle of ΣANs. The diurnal maximums of 200 pptv for ΣPNs and ΣANs are well below the peaks reported in other forest sites. A box model constrained with measured species, reproduces well the observed ΣPNs, but overestimates ΣANs concentrations. The reason of this model-observation discrepancy could be a wrong parameterization in the isoprene nitrates (INs chemistry mechanism. Sensitivity tests show that: (1 reducing the yield of INs from the reaction of peroxy nitrates with NO to almost the lowest values reported in literature (5%, (2 reducing the INs recycling to 70% and (3 keeping the INs dry deposition at 4 cm s−1, improve the agreement between modelled and measured ΣANs of 20% on average. These results imply that in the tropical rain forest, even if ΣPNs and ΣANs concentrations are lower than those observed in other North American forests, the yield and dry deposition of INs are similar. Another comparable result is that in the INs oxidation its recycling dominates with only a 30% release of NO2, which has implications on tropospheric ozone production and aerosol budget.

  17. Formation and plasma circulation of solar prominences

    CERN Document Server

    Xia, Chun

    2016-01-01

    Solar prominences are long-lived cool and dense plasma curtains in the hot and rarefied outer solar atmosphere or corona. The physical mechanism responsible for their formation and especially for their internal plasma circulation has been uncertain for decades. The observed ubiquitous down flows in quiescent prominences are difficult to interpret as plasma with high conductivity seems to move across horizontal magnetic field lines. Here we present three-dimensional numerical simulations of prominence formation and evolution in an elongated magnetic flux rope as a result of in-situ plasma condensations fueled by continuous plasma evaporation from the solar chromosphere. The prominence is born and maintained in a fragmented, highly dynamic state with continuous reappearance of multiple blobs and thread structures that move mainly downward dragging along mass-loaded field lines. The prominence plasma circulation is characterized by the dynamic balance between the drainage of prominence plasma back to the chromos...

  18. [William Harvey, discoverer of the blood circulation].

    Science.gov (United States)

    v Mühlendahl, K E

    2007-06-01

    William Harvey (1578-1657), living at the turn to modern times, scientifically speaking, was an eminent physician and scientist. He developed the concept of the circulation of the blood and his findings have proved to be correct in nearly all details to this day. He published his physiological findings and interpretations in a small, albeit epoch-making, volume: Exercitatio anatomica de motu cordis et sanguinis in animalibus, published in Frankfurt in 1628. On the occasion of the 350th anniversary of his death on June 3, 2007, this essay commemorates the work of this important physician, illustrating his brilliant conception of the blood circulation by quoting passages from De motu cordis et sanguinis.

  19. Modeling mesoscale circulation of the Black Sea

    Science.gov (United States)

    Korotenko, K. A.

    2015-11-01

    An eddy-resolving (1/30)° version of the DieCAST low-dissipative model, adapted to the Black Sea circulation, is presented. Under mean climatological forcing, the model realistically reproduces major dominant large-scale and mesoscale structures of seasonal sea circulation, including the Rim Current, coastal anticyclonic eddies, mushroom currents, etc. Due to its extremely low dissipation and high resolution, the model makes it possible to trace the development of the baroclinic instability along the Turkish and Caucasian coasts, reproduce mesoscale structures generated by this mechanism, and assess the scales of these structures. The model also realistically reproduces short-term effects of bora winds on the evolution of subsurface layer structures.

  20. Meridional circulation in turbulent protoplanetary disks

    CERN Document Server

    Fromang, Sebastien; Masset, Frederic

    2011-01-01

    Based on viscous disk theory, a number of recent studies have suggested the existence of a large scale meridional circulation in protoplanetary disks. Such a flow could account for the presence of crystalline silicates, among which Calcium and Aluminium-rich Inclusions (CAIs), at large distances from the sun. This paper aims at examining whether such large scale flows exist in turbulent protoplanetary disks. High resolution global hydrodynamical and magnetohydrodynamical numerical simulations of turbulent protoplanetary disks are used to infer the properties of the flow in such disks. By performing hydrodynamic simulations using explicit viscosity, we demonstrate that our numerical setup does not suffer from any numerical artifact. The aforementioned meridional circulation is readily recovered in viscous and laminar disks. In MHD simulations, the magneto-rotational instability drives turbulence in the disks. Averaging out the turbulent fluctuations over long timescale, the results fail to show any large scale...

  1. Circulation control STOL aircraft design aspects

    Science.gov (United States)

    Loth, John L.

    1987-01-01

    Since Davidson patented Circulation Control Airfoils in 1960, there have been only 2 aircraft designed and flown with circulation control (CC). Designing with CC is complex for the following reasons: the relation between lift increase and blowing momentum is nonlinear; for good cruise performance one must change the wing geometry in flight from a round to a sharp trailing edge. The bleed air from the propulsion engines or an auxiliary compressor, must be used efficiently. In designing with CC, the propulsion and control aspects are just as important as aerodynamics. These design aspects were examined and linearized equations are presented in order to facilitate a preliminary analysis of the performance potential of CC. The thrust and lift requirements for takeoff make the calculated runway length very sensitive to the bleed air ratio. Thrust vectoring improves performance and can offset nose down pitching moments. The choice of blowing jet to free stream velocity ratio determines the efficiency of applying bleed air power.

  2. The design of large natural circulation BWR's

    International Nuclear Information System (INIS)

    Boiling water reactors (BWR) with natural circulation are applied for capacities up to 60 MWe. Based on scale studies, however, it appears that larger production units are more efficient. It is recommended to investigate the bottlenecks in realizing larger reactors (>1000 MWe). The aim of the study on the title subject is to study to what extent the production capacity of BWRs with natural circulation can be increased. Based on data from the literature a simple analytic method has been chosen and existing BWR designs were compared. Capacities of 1300 MWe appear to be possible. These reactors will have a smaller pin diameter and a lower water supply temperature. Also steam separators with a minor pressure reduction must be available. The reliability of the stability measurement must be increased. Based on the results of this investigation the priorities for research on the design of future BWRs have been determined

  3. Genetically Encoded Voltage Indicators in Circulation Research.

    Science.gov (United States)

    Kaestner, Lars; Tian, Qinghai; Kaiser, Elisabeth; Xian, Wenying; Müller, Andreas; Oberhofer, Martin; Ruppenthal, Sandra; Sinnecker, Daniel; Tsutsui, Hidekazu; Miyawaki, Atsushi; Moretti, Alessandra; Lipp, Peter

    2015-09-08

    Membrane potentials display the cellular status of non-excitable cells and mediate communication between excitable cells via action potentials. The use of genetically encoded biosensors employing fluorescent proteins allows a non-invasive biocompatible way to read out the membrane potential in cardiac myocytes and other cells of the circulation system. Although the approaches to design such biosensors date back to the time when the first fluorescent-protein based Förster Resonance Energy Transfer (FRET) sensors were constructed, it took 15 years before reliable sensors became readily available. Here, we review different developments of genetically encoded membrane potential sensors. Furthermore, it is shown how such sensors can be used in pharmacological screening applications as well as in circulation related basic biomedical research. Potentials and limitations will be discussed and perspectives of possible future developments will be provided.

  4. Posterior circulation revascularization to manage vertebrobasilar occlusion

    Directory of Open Access Journals (Sweden)

    SHANG Yan-guo

    2012-06-01

    Full Text Available Objective To discuss the technique and effect of posterior circulation revascularization to manage vertebrobasilar occlusion. Methods Nine patients with vertebrobasilar occlusion were treated by using occipital artery-posterior inferior cerebellar artery bypass, superficial temporal artery-superior cerebellar artery bypass, superficial temporal artery-posterior cerebral artery bypass and occipital artery-vertebral artery bypass with radial artery graft. Results Intraoperative indocyanine green angiography showed all the bypass arteries were patent. Postoperative DSA or CTA showed bypass arteries patent in 8 patients, among whom seven patients got obvious improvement on MR or CT perfusion. One patient died of heart failure on the 15th day postoperative. During the follow-up of eight patients, no stroke reoccurred, four patients got back to nearly normal life. Conclusion Most of the patients with vertebrobasilar occlusion could benefit from the posterior circulation revascularization, which should be confirmed by randomized controlled clinical trials in the future.

  5. Effect of nitrate on activity and community structure of a sulfidogenic wastewater biofilm

    DEFF Research Database (Denmark)

    Kofoed, Michael Vedel Wegener; Mohanakrishnan, Janani; Schramm, Andreas;

    to the reactor for 10 days. Gradients of nitrate and sulfide were recorded with microsensors before and after the addition of nitrate, and changes in community composition and biofilm activity were monitored on DNA and RNA level by denaturing gradient gel electrophoresis of 16S rRNA, sulfite reductase......-like SRB to Desulfomicrobium-like species. Fluoresence in situ hybridization of SRB confirmed the shift and furthermore demonstrated that SRB, after nitrate addition, were overgrown by other, presumably nitrate reducing bacteria. Genes and transcripts of the periplasmic nitrate reductase could only...

  6. Cluster Dynamics in a Circulating Fluidized Bed

    Energy Technology Data Exchange (ETDEWEB)

    Guenther, C.P.; Breault, R.W.

    2006-11-01

    A common hydrodynamic feature in industrial scale circulating fluidized beds is the presence of clusters. The continuous formation and destruction of clusters strongly influences particle hold-up, pressure drop, heat transfer at the wall, and mixing. In this paper fiber optic data is analyzed using discrete wavelet analysis to characterize the dynamic behavior of clusters. Five radial positions at three different axial locations under five different operating were analyzed using discrete wavelets. Results are summarized with respect to cluster size and frequency.

  7. First circulating beam in the AA

    CERN Multimedia

    1980-01-01

    On 3 July 1980, two years after project authorization, beam circulated for the first time in the AA. It was a 3.5 GeV/c proton test beam. We see an expecting crowd, minutes before the happy event. The persons are to numerous to name them all. Heribert Koziol, apparently asleep, is answering the call from an impatient director. See also 8007094.

  8. Water circulation forecasting in Spanish harbours

    OpenAIRE

    Grifoll, Manel; Jordá, Gabriel; Sotillo, Marcos G.; Ferrer, Luis; Espino, Manuel; Sánchez-Arcilla, Agustín; Álvarez-Fanjul, Enrique

    2012-01-01

    This paper describes the first harbour circulation forecasting system implemented in Spain. The configuration design was based on previous analyses of the morphologic and hydrodynamic behaviour of three harbours: Barcelona, Tarragona and Bilbao. A nested system of oceanic models was implemented, with a scope ranging from the regional scale (with a mean horizontal resolution of 5 km) to the harbour scale (with a mean horizontal resolution of 40 m). A set of sensitivity tests was carried out in...

  9. The creation and circulation of public geographies

    OpenAIRE

    Kitchin, Rob; Linehan, Denis; O'Callaghan, Cian; Lawton, Philip

    2013-01-01

    In response to the commentaries, we discuss further how social media disrupts and remakes the creation and circulation of geographical knowledges and potentially reconfigures the moral economy of the social sciences. In particular, we examine questions of what is meant by public geography, the publics which such geographies serve, alternative and complementary approaches to social media, the politics of authorship within collective blogs, the politics and mechanisms of knowledge c...

  10. Parallel Computing of Ocean General Circulation Model

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    This paper discusses the parallel computing of the thirdgeneration Ocea n General Circulation Model (OGCM) from the State Key Laboratory of Numerical Mo deling for Atmospheric Science and Geophysical Fluid Dynamics(LASG),Institute of Atmosphere Physics(IAP). Meanwhile, several optimization strategies for paralle l computing of OGCM (POGCM) on Scalable Shared Memory Multiprocessor (S2MP) are presented. Using Message Passing Interface (MPI), we obtain super linear speedup on SGI Origin 2000 for parallel OGCM(POGCM) after optimization.

  11. Circulating fluidized bed boilers design and operations

    CERN Document Server

    Basu, Prabir

    1991-01-01

    This book provides practicing engineers and students with insight into the design and operation of circulating fluidized bed (CFB) boilers. Through a combination of theoretical concepts and practical experience, this book gives the reader a basic understanding of the many aspects of this subject.Important environmental considerations, including solid waste disposal and predicted emissions, are addressed individually in separate chapters. This book places an emphasis on combustion, hydrodynamics, heat transfer, and material issues, and illustrates these concepts with numerous examples of pres

  12. Circulating somatostatin. Physiological regulator of pancreatic function?

    OpenAIRE

    Gyr, K; Beglinger, C; Köhler, E; Trautzl, U; Keller, U.; Bloom, S R

    1987-01-01

    The present study was designed to determine whether somatostatin is released into the circulation in sufficient amounts to regulate exocrine and endocrine pancreatic function and to evaluate the possible role of somatostatin as a hormonal regulator of the pancreas. Mean plasma somatostatin levels (SLI) increased from 11 +/- 2 pmol liter-1 to peak concentrations of 18 +/- 2 in six healthy male volunteers after a steak meal (P less than 0.05). Infusion of somatostatin inhibited hormone-induced ...

  13. When Prostate Cancer Circulates in the Bloodstream

    Directory of Open Access Journals (Sweden)

    Virginie Vlaeminck-Guillem

    2015-10-01

    Full Text Available Management of patients with prostate cancer is currently based on imperfect clinical, biological, radiological and pathological evaluation. Prostate cancer aggressiveness, including metastatic potential, remains difficult to accurately estimate. In an attempt to better adapt therapeutics to an individual (personalized medicine, reliable evaluation of the intrinsic molecular biology of the tumor is warranted, and particularly for all tumor sites (primary tumors and secondary sites at any time of the disease progression. As a consequence of their natural tendency to grow (passive invasion or as a consequence of an active blood vessel invasion by metastase-initiating cells, tumors shed various materials into the bloodstream. Major efforts have been recently made to develop powerful and accurate methods able to detect, quantify and/or analyze all these circulating tumor materials: circulating tumors cells, disseminating tumor cells, extracellular vesicles (including exosomes, nucleic acids, etc. The aim of this review is to summarize current knowledge about these circulating tumor materials and their applications in translational research.

  14. Acoustic streaming and Sun's meridional circulation

    Science.gov (United States)

    Valverde, Jose Manuel

    2016-09-01

    A vast number of physical processes involving oscillations of a bounded viscous fluid are relevantly influenced by acoustic streaming. When this happens a steady circulation of fluid develops in a thin boundary adjacent to the interface. Some examples are refracted sound waves, a fluid inside a spherical cavity undergoing torsional oscillations or a pulsating liquid droplet. Steady streaming around circular interfaces consists of a hemispherically symmetric recirculation of fluid from the equatorial plane to the polar axes closely resembling the meridional circulation pattern observed in the Sun's convection zone that determines the solar cycle. In this paper, it is argued that the acoustic pulsations exhibited by the Sun would lead to acoustic streaming in the boundary of the convection zone. A simple estimation using a typical dominant frequency of 3 mHz and the observed surface oscillation amplitude yields a steady streaming velocity us ∼ 10 m s‑1, which is on the order of the meridional circulation velocity observed in the Sun's convection zone.

  15. Circulation in a Short Cylindrical Couette System

    Energy Technology Data Exchange (ETDEWEB)

    Akira Kageyama; Hantao Ji; Jeremy Goodman

    2003-07-08

    In preparation for an experimental study of magnetorotational instability (MRI) in liquid metal, we explore Couette flows having height comparable to the gap between cylinders, centrifugally stable rotation, and high Reynolds number. Experiments in water are compared with numerical simulations. The flow is very different from that of an ideal, infinitely long Couette system. Simulations show that endcaps co-rotating with the outer cylinder drive a strong poloidal circulation that redistributes angular momentum. Predicted toroidal flow profiles agree well with experimental measurements. Spin-down times scale with Reynolds number as expected for laminar Ekman circulation; extrapolation from two-dimensional simulations at Re less than or equal to 3200 agrees remarkably well with experiment at Re approximately equal to 106. This suggests that turbulence does not dominate the effective viscosity. Further detailed numerical studies reveal a strong radially inward flow near both endcaps. After turning vertically along the inner cylinder, these flows converge at the midplane and depart the boundary in a radial jet. To minimize this circulation in the MRI experiment, endcaps consisting of multiple, differentially rotating rings are proposed. Simulations predict that an adequate approximation to the ideal Couette profile can be obtained with a few rings.

  16. Elevated circulating somatostatin levels in acromegaly.

    Science.gov (United States)

    Arosio, M; Porretti, S; Epaminonda, P; Giavoli, C; Gebbia, C; Penati, C; Beck-Peccoz, P; Peracchi, M

    2003-06-01

    GH increases hypothalamic somatostatin (SS) synthesis and secretion but it is unknown if chronic GH excess, as found in acromegaly, may influence circulating SS levels, that are mainly of enteropancreatic source and affect several gastrointestinal functions, including motility. Circulating SS occurs in several post-translational forms including somatostatin-14 (SS-14), somatostatin-28 (SS-28) and other small peptides. The aim of the present study was to characterize the fasting and postprandial pattern of plasma circulating somatostatin in normal subjects and patients with acromegaly. Fasting total SS and SS-28 levels were measured in 32 subjects, 16 acromegalic patients with a new diagnosis (A) (8 F, 8 M, median age 48) and 16 matched healthy volunteers (C) (8 F, 8 M, median age 45). SS was also determined after a standard solid-liquid meal (550 kCal) in 24 of the subjects (12 C and 12 A). Fasting SS and SS-28 were significantly higher in acromegalic patients as compared to healthy subjects. In the former, a positive correlation was found between IGF-I and SS levels (r = 0.525 p acromegaly. Excess GH/IGF-I could be a causal factor in somatostatin hypersecretion. Conceivably this abnormality might play a role in some alterations of gastrointestinal function of acromegalic patients such as prolonged bowel transit.

  17. The protein corona of circulating PEGylated liposomes.

    Science.gov (United States)

    Palchetti, Sara; Colapicchioni, Valentina; Digiacomo, Luca; Caracciolo, Giulio; Pozzi, Daniela; Capriotti, Anna Laura; La Barbera, Giorgia; Laganà, Aldo

    2016-02-01

    Following systemic administration, liposomes are covered by a 'corona' of proteins, and preserving the surface functionality is challenging. Coating the liposome surface with polyethylene glycol (PEG) is the most widely used anti-opsonization strategy, but it cannot fully preclude protein adsorption. To date, protein binding has been studied following in vitro incubation to predict the fate of liposomes in vivo, while dynamic incubation mimicking in vivo conditions remains largely unexplored. The main aim of this investigation was to determine whether shear stress, produced by physiologically relevant dynamic flow, could influence the liposome-protein corona. The corona of circulating PEGylated liposome was thoroughly compared with that formed by incubation in vitro. Systematic comparison in terms of size, surface charge and quantitative composition was made by dynamic light scattering, microelectrophoresis and nano-liquid chromatography tandem mass spectrometry (nanoLC-MS/MS). Size of coronas formed under static vs. dynamic incubation did not appreciably differ from each other. On the other side, the corona of circulating liposomes was more negatively charged than its static counterpart. Of note, the variety of protein species in the corona formed in a dynamic flow was significantly wider. Collectively, these results demonstrated that the corona of circulating PEGylated liposomes can be considerably different from that formed in a static fluid. This seems to be a key factor to predict the biological activity of a liposomal formulation in a physiological environment.

  18. Tropical convective transport and the Walker circulation

    Directory of Open Access Journals (Sweden)

    J. S. Hosking

    2012-10-01

    Full Text Available We introduce a methodology to visualise rapid vertical and zonal tropical transport pathways. Using prescribed sea-surface temperatures in four monthly model integrations for 2005, we characterise preferred transport routes from the troposphere to the stratosphere in a high resolution climate model. Most efficient transport is modelled over the Maritime Continent (MC in November and February, i.e., boreal winter. In these months, the ascending branch of the Walker Circulation over the MC is formed in conjunction with strong deep convection, allowing fast transport into the stratosphere. In the model the upper tropospheric zonal winds associated with the Walker Circulation are also greatest in these months in agreement with ERA-Interim reanalysis data. We conclude that the Walker circulation plays an important role in the seasonality of fast tropical transport from the lower and middle troposphere to the upper troposphere and so impacts at the same time the potential supply of surface emissions to the tropical tropopause layer (TTL and subsequently to the stratosphere.

  19. Influence of macrophytes on nitrate removal in wetlands

    Energy Technology Data Exchange (ETDEWEB)

    Weisner, S.E.B.; Eriksson, Peder G.; Graneli, W.; Leonardson, L. (Lund Univ. (Sweden). Dept. of Ecology)

    1994-01-01

    Efficient nitrate removal from wetlands depends on denitrification. Macrophytes support denitrification by supplying organic carbon. Organic carbon available to denitrifying bacteria is released from plant litter and from living macrophytes. Macrophytes offer attachment surfaces for epiphytes, also producing organic matter, and for denitrifying bacteria. Emergent macrophytes are generally more productive than submerged macrophytes, but submerged macrophytes have more epiphytes and offer a larger attachment area in the water column for denitrifying bacteria. Emergent and submerged vegetation differ in their seasonal patterns of release of organic carbon. We conclude that a mixture of emergent and submerged macrophytes may be beneficial for nitrogen removal in wetlands with a surface-flow of nitrate-rich water. The influence of vegetation on wetland hydraulics must also be considered. A wetland design with deeper parts favoring submerged macrophytes alternating, along the water flow, with shallower parts covered by emergent macrophytes, may promote denitrification processes and distribution of water flow. 41 refs, 5 figs

  20. Nuclear microprobe imaging of gallium nitrate in cancer cells

    Science.gov (United States)

    Ortega, Richard; Suda, Asami; Devès, Guillaume

    2003-09-01

    Gallium nitrate is used in clinical oncology as treatment for hypercalcemia and for cancer that has spread to the bone. Its mechanism of antitumor action has not been fully elucidated yet. The knowledge of the intracellular distribution of anticancer drugs is of particular interest in oncology to better understand their cellular pharmacology. In addition, most metal-based anticancer compounds interact with endogenous trace elements in cells, altering their metabolism. The purpose of this experiment was to examine, by use of nuclear microprobe analysis, the cellular distribution of gallium and endogenous trace elements within cancer cells exposed to gallium nitrate. In a majority of cellular analyses, gallium was found homogeneously distributed in cells following the distribution of carbon. In a smaller number of cells, however, gallium appeared concentrated together with P, Ca and Fe within round structures of about 2-5 μm diameter located in the perinuclear region. These intracellular structures are typical of lysosomial material.

  1. Engineering Options Assessment Report. Nitrate Salt Waste Stream Processing

    Energy Technology Data Exchange (ETDEWEB)

    Anast, Kurt Roy [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-11-13

    This report examines and assesses the available systems and facilities considered for carrying out remediation activities on remediated nitrate salt (RNS) and unremediated nitrate salt (UNS) waste containers at Los Alamos National Laboratory (LANL). The assessment includes a review of the waste streams consisting of 60 RNS, 29 above-ground UNS, and 79 candidate below-ground UNS containers that may need remediation. The waste stream characteristics were examined along with the proposed treatment options identified in the Options Assessment Report . Two primary approaches were identified in the five candidate treatment options discussed in the Options Assessment Report: zeolite blending and cementation. Systems that could be used at LANL were examined for housing processing operations to remediate the RNS and UNS containers and for their viability to provide repackaging support for remaining LANL legacy waste.

  2. Engineering Options Assessment Report: Nitrate Salt Waste Stream Processing

    Energy Technology Data Exchange (ETDEWEB)

    Anast, Kurt Roy [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-11-18

    This report examines and assesses the available systems and facilities considered for carrying out remediation activities on remediated nitrate salt (RNS) and unremediated nitrate salt (UNS) waste containers at Los Alamos National Laboratory (LANL). The assessment includes a review of the waste streams consisting of 60 RNS, 29 aboveground UNS, and 79 candidate belowground UNS containers that may need remediation. The waste stream characteristics were examined along with the proposed treatment options identified in the Options Assessment Report . Two primary approaches were identified in the five candidate treatment options discussed in the Options Assessment Report: zeolite blending and cementation. Systems that could be used at LANL were examined for housing processing operations to remediate the RNS and UNS containers and for their viability to provide repackaging support for remaining LANL legacy waste.

  3. Nuclear microprobe imaging of gallium nitrate in cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Ortega, Richard E-mail: ortega@cenbg.in2p3.fr; Suda, Asami; Deves, Guillaume

    2003-09-01

    Gallium nitrate is used in clinical oncology as treatment for hypercalcemia and for cancer that has spread to the bone. Its mechanism of antitumor action has not been fully elucidated yet. The knowledge of the intracellular distribution of anticancer drugs is of particular interest in oncology to better understand their cellular pharmacology. In addition, most metal-based anticancer compounds interact with endogenous trace elements in cells, altering their metabolism. The purpose of this experiment was to examine, by use of nuclear microprobe analysis, the cellular distribution of gallium and endogenous trace elements within cancer cells exposed to gallium nitrate. In a majority of cellular analyses, gallium was found homogeneously distributed in cells following the distribution of carbon. In a smaller number of cells, however, gallium appeared concentrated together with P, Ca and Fe within round structures of about 2-5 {mu}m diameter located in the perinuclear region. These intracellular structures are typical of lysosomial material.

  4. Dynamic Changes of Nitrate Reductase Activity within 24 Hours

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    [Objective] The research aimed to study the circadian rhythm of nitrate re- ductase activity (NRA) in plant. [Method] The wheat plants at heading stage were used as the materials for the measurement of dynamic changes of nitrate reductase activity (NRA) within 24 h under the conditions of constant high temperature. [Resulti The fluctuation of NRA in wheat changed greatly from 20:00 pm to 11:00 am. The enzyme activity remained constant, but at 14:00 the enzyme activity was the high- est, higher than all the other time points except the enzyme activity measured at11:00. The enzyme activity was the lowest of 17:00, which was lower than all the other time points except the enzyme activity measured at 2:00. [Conclusion] There were autonomous rhythm changes of NRA in wheat in a certain degree.

  5. Nitrate and Perchlorate removal from groundwater by ion exchange

    Energy Technology Data Exchange (ETDEWEB)

    Burge, S; Halden, R

    1999-09-15

    This study was conducted to evaluate the performance of a small scale ion exchange unit (Krudico, Inc of Auborn, IA) for removal of nitrate and perchlorate from groundwater at Lawrence Livermore National Laboratory's Site 300. The unit was able to treat 3,600 gallons of Site 300 groundwater, at an average influent concentration of 100 mg/L NO{sub 3}{sup -} before breakthrough occurred. The unit contained 2.5 ft{sup 3} of Sybron SR-7 resin. Seventy gallons of regeneration waste were generated (water treated to waste ratio of 51:1). The effluent concentration was about 20 mg/L NO{sub 3}{sup -}, which is equivalent to a treatment efficiency of at least 80%. There are several options for implementing this technology at Site 300. A target well, in the 817 area, has been selected. It has a 3 to 4 gpm flow rate, and concentrations of 90 mg/L NO{sub 3}{sup -} and 40 {micro}g/L perchlorate. The different treatment options include ion exchange treatment of nitrate only, nitrate and perchlorate, or perchlorate only. Option 1: For the treatment of nitrate only, this unit will be able to treat 3,700 gallons of water before regeneration is required. If both columns of the ion exchange unit are used, 7,400 gallons could be treated before the columns will need to be regenerated (producing 140 gallons of waste, per cycle or every 1.5 days). The effluent nitrate concentration is expected to be about 17 mg/L. Annual operation and maintenance costs are estimated to be $0.14 per gallon of water treated. Option 2: If only perchlorate is to be removed with ion exchange at the 817 area, a smaller unit should be considered. A 55 gallon canister filled with ion exchange resin should be able to reduce perchlorate concentrations in the groundwater from 40 {micro}g/L to non-detect levels for three years before the resin would need to be replaced. The contaminant-laden resin would be disposed of as hazardous waste. It is not practical to regenerate the resin because of the extreme

  6. Design and evaluation of liposomal formulation of pilocarpine nitrate

    Directory of Open Access Journals (Sweden)

    Rathod S

    2010-01-01

    Full Text Available Prolonged release drug delivery system of pilocarpine nitrate was made by optimizing thin layer film hydration method. Egg phosphatidylcholine and cholesterol were used to make multilamellar vesicles. Effects of charges over the vesicles were studied by incorporating dicetylphosphate and stearylamine. Various factors, which may affect the size, shape, encapsulation efficiency and release rate, were studied. Liposomes in the size range 0.2 to 1 ΅m were obtained by optimizing the process. Encapsulation efficiency of neutral, positive and negatively charged liposomes were found to be 32.5, 35.4 and 34.2 percent, respectively. In vitro drug release rate was studied on specially designed model. Biological response in terms of reduction in intraocular pressure was observed on rabbit eyes. Pilocarpine nitrate liposomes were lyophilized and stability studies were conducted.

  7. Thermal stability assessment of anti-explosive ammonium nitrate

    Institute of Scientific and Technical Information of China (English)

    Lijin Shen; Xuguang Wang

    2005-01-01

    The explosivity experiment of anti-explosive ammonium nitrate (AEAN) shows that the explosive characteristic of AEAN is eliminated. The adiabatic decompositions of ammonium nitrate and AEAN were investigated with an accelerating rate calorimeter (ARC). The curves of thermal decomposition temperature and pressure versus time, self-heating rate and pressure versus temperature for two systems were obtained. The kinetic parameters such as apparent activation energy and pre-exponential factor were calculated.The safety of AEAN was analyzed. It was indicated that AEAN has a higher thermal stability than AN. At the same time, it can be shown that the elimination of its explosive characteristic is due to the improvement on the thermal stability of AEAN.

  8. Engineering Options Assessment Report. Nitrate Salt Waste Stream Processing

    International Nuclear Information System (INIS)

    This report examines and assesses the available systems and facilities considered for carrying out remediation activities on remediated nitrate salt (RNS) and unremediated nitrate salt (UNS) waste containers at Los Alamos National Laboratory (LANL). The assessment includes a review of the waste streams consisting of 60 RNS, 29 above-ground UNS, and 79 candidate below-ground UNS containers that may need remediation. The waste stream characteristics were examined along with the proposed treatment options identified in the Options Assessment Report . Two primary approaches were identified in the five candidate treatment options discussed in the Options Assessment Report: zeolite blending and cementation. Systems that could be used at LANL were examined for housing processing operations to remediate the RNS and UNS containers and for their viability to provide repackaging support for remaining LANL legacy waste.

  9. Isopiestic density law of actinide nitrates applied to criticality calculations

    International Nuclear Information System (INIS)

    Up to now, criticality safety experts used density laws fitted on experimental data and applied them in and outside the measurement range. Depending on the case, such an approach could be wrong for nitrate solutions. Seven components are concerned: UO2(NO3)2, U(NO3)4, Pu(NO3)4, Pu(NO3)3, Th(NO3)4, Am(NO3)3 and HNO3. To get rid of this problem, a new methodology based on the thermodynamic concept of binary electrolytes solutions mixtures at constant water activity, so called 'isopiestic' solutions, has been developed by IRSN to calculate the nitrate solutions density. This article shortly presents the theoretical aspects of the method, its qualification using benchmarks and its implementation in IRSN graphical user interface. (author)

  10. Hydroxylamine nitrate self-catalytic kinetics study with adiabatic calorimetry.

    Science.gov (United States)

    Liu, Lijun; Wei, Chunyang; Guo, Yuyan; Rogers, William J; Sam Mannan, M

    2009-03-15

    Hydroxylamine nitrate (HAN) is an important member of the hydroxylamine compound family with applications that include equipment decontamination in the nuclear industry and aqueous or solid propellants. Due to its instability and autocatalytic behavior, HAN has been involved in several incidents at the Hanford and Savannah River Site (SRS) [Technical Report on Hydroxylamine Nitrate, US Department of Energy, 1998]. Much research has been conducted on HAN in different areas, such as combustion mechanism, decomposition mechanism, and runaway behavior. However, the autocatalytic decomposition behavior of HAN at runaway stage has not been fully addressed due to its highly exothermic and rapid decomposition behavior. This work is focused on extracting HAN autocatalytic kinetics and analyzing HAN critical behavior from adiabatic calorimetry measurements. A lumped autocatalytic kinetic model for HAN and associated model parameters are determined. Also the storage and handling critical conditions of diluted HAN solution without metal presence are quantified.

  11. Hormones and nitrate: a two-way connection.

    Science.gov (United States)

    Krouk, Gabriel

    2016-08-01

    During their sessile mode of life, plants need to endure variations in their environment such as a drastic variability in the nutrient concentration in soil solution. It is almost trivial to say that such fluctuations in the soil modify plant growth, development and phase transitions. However, the signaling pathways underlying the connections between nitrogen related signaling and hormonal signaling controlling growth are still poorly documented. This review is meant to present how nitrate/nitrogen controls hormonal pathways. Furthermore, it is very interesting to highlight the increasing evidence that the hormonal signaling pathways themselves seem to feed back control of the nitrate/nitrogen transport and assimilation to adapt nutrition to growth. This thus defines a feed-forward cycle that finely coordinates plant growth and nutrition. PMID:27003907

  12. Surface chemistry of electrospun cellulose nitrate nanofiber membranes.

    Science.gov (United States)

    Nartker, Steven; Askeland, Per; Wiederoder, Sara; Drzal, Lawrence T

    2011-02-01

    Electrospinning is a rapidly developing technology that provides a unique way to produce novel polymer nanofibers with controllable diameters. Cellulose nitrate non-woven mats of submicron-sized fibers with diameters of 100-1200 nm were prepared. The effects of processing equipment collector design void gap, and steel drum coated with polyvinylidene dichloride (PVDC) were investigated. The PVDC layer applied to the rotating drum aided in fiber harvesting. Electron microscopy (FESEM and ESEM) studies of as-spun fibers revealed that the morphology of cellulose nitrate fibers depended on the collector type and solution viscosity. When a rotating steel drum was employed a random morphology was observed, while the void gap collector produced aligned fiber mats. Increases in viscosity lead to larger diameter fibers. The fibers collected were free from all residual solvents and could undergo oxygen plasma treatment to increase the hydropholicity. PMID:21456166

  13. Contrasting nitrate adsorption in Andisols of two coffee plantations in Costa Rica.

    Science.gov (United States)

    Ryan, M C; Graham, G R; Rudolph, D L

    2001-01-01

    Fertilizer use in coffee plantations is a suspected cause of rising ground water nitrate concentrations in the ground water-dependent Central Valley of Costa Rica. Nitrate adsorption was evaluated beneath two coffee (Coffea arabica L.) plantations in the Central Valley. Previous work at one site had identified unsaturated zone nitrate retardation relative to a tritium tracer. Differences in nitrate adsorption were assessed in cores to 4 m depth in Andisols at this and one other plantation using differences in KCl- and water-extractable nitrate as an index. Significant adsorption was confirmed at the site of the previous tracer test, but not at the second site. Anion exchange capacity, X-ray diffraction data, extractable Al and Si, and soil pH in NaF corroborated that differences in adsorption characteristics were related to subtle differences in clay mineralogy. Soils at the site with significant nitrate adsorption showed an Al-rich allophane clay content compared with a more weathered, Si-rich allophane and halloysite clay mineral content at the site with negligible adsorption. At the site with significant nitrate adsorption, nitrate occupied less than 10% of the total anion adsorption capacity, suggesting that adsorption may provide long-term potential for mitigation or delay of nitrate leaching. Evaluation of nitrate sorption potential of soil at local and landscape scales would be useful in development of nitrogen management practices to reduce nitrate leaching to ground water.

  14. Formation of germline chimera Gaok chicken used circulation primordial germ cells (circulation PGCs fresh and thawed

    Directory of Open Access Journals (Sweden)

    Kostaman T

    2014-03-01

    Full Text Available Formation of germline chimeras by transfer of chicken primordial germ cells (PGCs is one of the effective techniques for preservation and regeneration of genetic resources in chickens. This study attempted to form germline chimeras of Gaok chicken buy purifying circulated PGCs of donor embryo before it is transferred to the recipient (White Leghorn chickens=WL and studied the ability of recipient embryo on survival in incubators, and hatchability. This study used 200 fertile eggs of Gaok and 90 fertile WL breed all of the eggs was incubated at 380C and 60% humidity in a portable incubator. PGCs-circulation of the blood collected Gaok embryos at stage 14-16 were taken from the dorsal aorta, and then purified by centrifugation method using nycodenz. PGCs-circulation results further purification frozen in liquid nitrogen before being transferred to the recipient embryo. The results showed that for the development of embryos transferred to the fresh circulation of PGCs-circulation as many as 25 cells can survive up to day 14, while one of the transferred of 50 and 100 cells into recipient embryos was hatched (10%. On the contrari recipient embryos that are transferred to the frozen PGCs-circulation the embryos development was shorter, and only survived until day 10th (treatment 25 cells, day 14th (treatment of 50 cells and day 17th (treatment of 100 cells. It is concluded that the amount of PGCs-circulation embryos transferred to the recipient is one factor that influence the success of the development germline chimeras.

  15. 19 CFR 207.63 - Circulation of draft questionnaires.

    Science.gov (United States)

    2010-04-01

    ... 19 Customs Duties 3 2010-04-01 2010-04-01 false Circulation of draft questionnaires. 207.63... SUBSIDIZED EXPORTS TO THE UNITED STATES Five-Year Reviews § 207.63 Circulation of draft questionnaires. (a) The Director shall circulate draft questionnaires to the parties for comment in each full review....

  16. Algorithms for Finding the Inverses of Factor Block Circulant Matrices

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    In this paper, algorithms for finding the inverse of a factor block circulant matrix,a factor block retrocirculant matrix and partitioned matrix with factor block circulant blocks over the complex field are presented respectively. In addition, two algorithms for the inverse of a factor block circulant matrix over the quaternion division algebra are proposed.

  17. Bacterially mediated removal of phosphorus and cycling of nitrate and sulfate in the waste stream of a "zero-discharge" recirculating mariculture system.

    Science.gov (United States)

    Krom, M D; Ben David, A; Ingall, E D; Benning, L G; Clerici, S; Bottrell, S; Davies, C; Potts, N J; Mortimer, R J G; van Rijn, J

    2014-06-01

    Simultaneous removal of nitrogen and phosphorus by microbial biofilters has been used in a variety of water treatment systems including treatment systems in aquaculture. In this study, phosphorus, nitrate and sulfate cycling in the anaerobic loop of a zero-discharge, recirculating mariculture system was investigated using detailed geochemical measurements in the sludge layer of the digestion basin. High concentrations of nitrate and sulfate, circulating in the overlying water (∼15 mM), were removed by microbial respiration in the sludge resulting in a sulfide accumulation of up to 3 mM. Modelling of the observed S and O isotopic ratios in the surface sludge suggested that, with time, major respiration processes shifted from heterotrophic nitrate and sulfate reduction to autotrophic nitrate reduction. The much higher inorganic P content of the sludge relative to the fish feces is attributed to conversion of organic P to authigenic apatite. This conclusion is supported by: (a) X-ray diffraction analyses, which pointed to an accumulation of a calcium phosphate mineral phase that was different from P phases found in the feces, (b) the calculation that the pore waters of the sludge were highly oversaturated with respect to hydroxyapatite (saturation index = 4.87) and (c) there was a decrease in phosphate (and in the Ca/Na molar ratio) in the pore waters simultaneous with an increase in ammonia showing there had to be an additional P removal process at the same time as the heterotrophic breakdown of organic matter. PMID:24657541

  18. Characteristics of nitrate horizontal transport in a paddy field of the Tai Lake region, China.

    Science.gov (United States)

    Chen, X M; Shen, Q R; Pan, G X; Liu, Z P

    2003-02-01

    The characteristics of nitrate horizontal transport in a major paddy soil, Wu Shan soil in the Tai Lake region, were studied. The concentration of nitrate during horizontal movement decreased with the increasing in distance from the tracer source, the change following a logarithmic function. The concentration of the nitrate was strongly correlated with the soil moisture content, as an exponential function. The horizontal transport velocity of nitrate was significantly correlated with the distance of the tracer source as power function. Therefore, the velocity of nitrate horizontal transport was controlled by the concentration gradient of nitrate, and soil water potential gradient from beginning to the 20 cm mark in the horizontal column. However, the velocity of nitrate horizontal was stable beyond 20 cm, where it was controlled by soil matric potential. PMID:12688479

  19. Investigation of processes leading to nitrate enrichment in soils in the Kalahari Region, Botswana

    Science.gov (United States)

    Schwiede, M.; Duijnisveld, W. H. M.; Böttcher, J.

    In Southern Africa elevated nitrate concentrations are observed in mostly uninhabited semi-arid areas. In the Kalahari of Botswana groundwater locally exhibits concentrations up to 600 mg/l. It is assumed, that nitrate found in the groundwater originates mainly from nitrogen input and transformations in the soils. Our investigations in the Kalahari between Serowe and Orapa show that cattle raising is an important source for enhanced nitrate concentrations in the soils (Arenosols). But also in termite mounds very high nitrate stocks were found, and under natural vegetation (acacia trees and shrubs) nitrate concentrations were mostly unexpectedly high. This nitrate enrichment in the soils poses a serious threat to the groundwater quality. However, calculated soil water age distributions in the unsaturated zone clearly show that today’s nitrate pollution of the groundwater below the investigation area could originate from natural sources, but cannot be caused by the current land use for cattle raising.

  20. Long-term fate of nitrate fertilizer in agricultural soils.

    Science.gov (United States)

    Sebilo, Mathieu; Mayer, Bernhard; Nicolardot, Bernard; Pinay, Gilles; Mariotti, André

    2013-11-01

    Increasing diffuse nitrate loading of surface waters and groundwater has emerged as a major problem in many agricultural areas of the world, resulting in contamination of drinking water resources in aquifers as well as eutrophication of freshwaters and coastal marine ecosystems. Although empirical correlations between application rates of N fertilizers to agricultural soils and nitrate contamination of adjacent hydrological systems have been demonstrated, the transit times of fertilizer N in the pedosphere-hydrosphere system are poorly understood. We investigated the fate of isotopically labeled nitrogen fertilizers in a three-decade-long in situ tracer experiment that quantified not only fertilizer N uptake by plants and retention in soils, but also determined to which extent and over which time periods fertilizer N stored in soil organic matter is rereleased for either uptake in crops or export into the hydrosphere. We found that 61-65% of the applied fertilizers N were taken up by plants, whereas 12-15% of the labeled fertilizer N were still residing in the soil organic matter more than a quarter century after tracer application. Between 8-12% of the applied fertilizer had leaked toward the hydrosphere during the 30-y observation period. We predict that additional exports of (15)N-labeled nitrate from the tracer application in 1982 toward the hydrosphere will continue for at least another five decades. Therefore, attempts to reduce agricultural nitrate contamination of aquatic systems must consider the long-term legacy of past applications of synthetic fertilizers in agricultural systems and the nitrogen retention capacity of agricultural soils.

  1. Nitrate contamination risk assessment in groundwater at regional scale

    Science.gov (United States)

    Daniela, Ducci

    2016-04-01

    Nitrate groundwater contamination is widespread in the world, due to the intensive use of fertilizers, to the leaking from the sewage network and to the presence of old septic systems. This research presents a methodology for groundwater contamination risk assessment using thematic maps derived mainly from the land-use map and from statistical data available at the national institutes of statistic (especially demographic and environmental data). The potential nitrate contamination is considered as deriving from three sources: agricultural, urban and periurban. The first one is related to the use of fertilizers. For this reason the land-use map is re-classified on the basis of the crop requirements in terms of fertilizers. The urban source is the possibility of leaks from the sewage network and, consequently, is linked to the anthropogenic pressure, expressed by the population density, weighted on the basis of the mapped urbanized areas of the municipality. The periurban sources include the un-sewered areas, especially present in the periurban context, where illegal sewage connections coexist with on-site sewage disposal (cesspools, septic tanks and pit latrines). The potential nitrate contamination map is produced by overlaying the agricultural, urban and periurban maps. The map combination process is very easy, being an algebraic combination: the output values are the arithmetic average of the input values. The groundwater vulnerability to contamination can be assessed using parametric methods, like DRASTIC or easier, like AVI (that involves a limited numbers of parameters). In most of cases, previous documents produced at regional level can be used. The pollution risk map is obtained by combining the thematic maps of the potential nitrate contamination map and the groundwater contamination vulnerability map. The criterion for the linkages of the different GIS layers is very easy, corresponding to an algebraic combination. The methodology has been successfully

  2. Observation of nitrate coatings on atmospheric mineral dust particles

    Directory of Open Access Journals (Sweden)

    W. J. Li

    2008-11-01

    Full Text Available Nitrate compounds have recently received much attention because of their ability to alter the hygroscopic properties and cloud condensation nuclei (CCN activity of mineral dust particles in the atmosphere. However, very little is known about specific characteristics of nitrate-coated mineral particles in an individual particle scale in field study. The sample collection was conducted during brown haze and dust episodes occurred between 24 May and 21 June 2007 in Beijing, northern China. The sizes, morphologies, and compositions of mineral dust particles together with their coatings were analyzed using transmission electron microscopy (TEM. 92% of the internally mixed mineral particles analyzed are covered with Ca-, Mg-, and Na-rich coatings, and 8% are associated with K- and S-rich coatings. The major coatings contain Ca, Mg, O, and N with minor amounts of S and Cl, suggesting that they are possibly nitrates mixed with less sulfates and chlorides. These nitrate coatings strongly relate with the presence of alkaline mineral components (e.g., calcite and dolomite within individual mineral particles. Calcium sulfate particles with the diameter from 10 to 500 nm were also detected within Ca(NO32 and Mg(NO32 coatings. Our results indicate that mineral particles in brown haze episodes were involved in atmospheric heterogeneous reactions with two or more acidic gases (e.g., SO2, NO2, HCl, and HNO3. Mineral particles that acquire hygroscopic coatings tend to be more spherical and larger. Such changes enhance their light scattering and CCN activity, both of which have cooling effects on the climate.

  3. Groundwater quality in Maharashtra, India: focus on nitrate pollution.

    Science.gov (United States)

    Gupta, Indrani; Salunkhe, Abhaysinh; Rohra, Nanda; Kumar, Rakesh

    2011-10-01

    Groundwater Survey and Development Agency (GSDA), Central Ground Water Board (CGWB) and Maharashtra Pollution Control Board (MPCB) have been carrying out groundwater quality monitoring at about 1407 monitoring locations in various districts of Maharashtra state in India. The groundwater quality data for pH, TDS, total hardness, sulphate, flouride and nitrate were compared with BIS: 10500:2004-2005 standards for drinking purpose. The results show that nitrate pollution is becoming more prevalent in groundwater of Maharashtra. Water quality data during the period 2007-2009 show that 544 locations out of 1407 locations exceeded 45 mgl(-1), the allowable NO3 level for drinking water. About 227 locations exceeded nitrate level beyond 100 mgl(-1). At 87 talukas in 23 districts of Maharashtra the NO3 levels exceeded the standard in all samples monitored during 2007-2009. The Buldana district with highest locations (27) had nitrate above 100 mgl(-1) followed by Amravati (24) and Akola (20) districts. At 7 talukas in 4 districts, fluoride was found above permissible limit of 1.5 mgl(-1), 100% of the time. 2 talukas in 2 districts of Maharashtra showed 100% non compliance of pH as per BIS standard of 6.5-8.5 mgl(-1). The districts having good to excellent quality of groundwater were Bhandara, Gondia, Kolhapur, Mumbai city, Mumbai Suburban, Nandurbar, Raigad, Ratnagiri, Satara, Sindhudurg, Thane and Washim. Vaijapur taluka in Aurangabad, Sinnar in Nashik and Kalambh taluka in Osmanabad have very poor water quality. Paithan taluka in Aurangabad, Shegaon taluka at Buldhana district, Amolner taluka at Jalgaon district and Jafrabad in Jalna district have water unsuitable for drinking.

  4. The Mechanism of Nitrate Pollution in Soil and Groundwater

    Institute of Scientific and Technical Information of China (English)

    王志敏; 诸葛敏; 杨玉峥

    2013-01-01

    Soil and groundwater which are important natural resources are closely related with human health.It will be hard to recover,if it is polluted.Nitrate has become one of the most serious harmful substances contaminated in soil and groundwater.A large number of studies have shown that high fertilizer and irrigation was the main reason of soil and groundwater pollution.Pollution is mainly concentrated in agricultural developed area.

  5. Transport of nitrated albumin across continuous vascular endothelium

    OpenAIRE

    Predescu, Dan; Predescu, Sanda; Malik, Asrar B.

    2002-01-01

    Because modification of plasma albumin on tyrosine residues generates nitrated albumin (NOA) that may function as a mechanism of nitrogen monoxide clearance from microcirculation, we investigated biochemicaly and morphologically the cell surface binding and the transendothelial transport of NOA. An electron microscopic study was carried out with mouse lungs and hearts perfused in situ with NOA and NOA-Au complexes. The results indicate that NOA-Au can bind to the endothelial cell surface, and...

  6. Nitrates in drinking water: relation with intensive livestock production

    OpenAIRE

    GIAMMARINO, M.; Quatto, P

    2015-01-01

    Summary Introduction. An excess of nitrates causes environmental pollution in receiving water bodies and health risk for human, if contaminated water is source of drinking water. The directive 91/676/ CEE [1] aims to reduce the nitrogen pressure in Europe from agriculture sources and identifies the livestock population as one of the predominant sources of surplus of nutrients that could be released in water and air. Directive is concerned about cattle, sheep, pigs and poultry and their territ...

  7. Nitrate leaching: comparing conventional, integrated and organic agricultural production systems

    OpenAIRE

    Haas, Guido; Berg, Martin; Köpke, Ulrich

    2002-01-01

    The impact of conventional, integrated and organic practices on groundwater quality were studied in northwestern Germany. Between 1993 and 1997 nitrogen budgets and the nitrate content of the unsaturated zone (soil sampling and porous suction cups) were measured in two field trials located on a clayey loam and a loamy sand, respectively. In each year of investigation three main crops per farming system were compared according to the defined site(soil)-adapted crop rotation. There was little d...

  8. Blood pressure, sodium intake, insulin resistance, and urinary nitrate excretion.

    Science.gov (United States)

    Facchini, F S; DoNascimento, C; Reaven, G M; Yip, J W; Ni, X P; Humphreys, M H

    1999-04-01

    The objective of this study was to investigate the relationships among various humoral factors thought to be involved in the regulation of blood pressure during high NaCl intake. Nineteen healthy subjects underwent sequential 5-day periods ingesting a low-sodium (25 mmol/d) or high-sodium (200 mmol/d) diet. Insulin resistance was assessed by the steady-state plasma glucose concentration at the end of a 3-hour insulin suppression test. Insulin resistance correlated inversely with natriuresis (P=0.04) and directly with increase in weight (P=0.03). The increase in mean arterial pressure associated with the high-sodium diet correlated directly with the gain in weight (P<0.05) and inversely with the increase in urinary nitrate excretion (P<0.0001). In a multiple regression model, more than 2/3 of the variance in mean arterial pressure was accounted for by the gain in weight and change in urinary nitrate excretion. The steady-state plasma glucose concentrations obtained with the 2 diets were similar, indicating that insulin resistance was unaffected by sodium intake. During high sodium intake, plasma renin activity and aldosterone decreased and plasma atrial natriuretic peptide increased; these changes did not correlate with the change in mean arterial pressure, insulin resistance, or change in urinary nitrate excretion. To the extent that urinary nitrate excretion reflects activity of the endogenous nitric oxide system, these results suggest that the salt sensitivity of mean arterial pressure may be related to blunted generation of endogenous nitric oxide. The results also demonstrate that insulin-resistant individuals have an impaired natriuretic response to high sodium intake. PMID:10205239

  9. Management options to limit nitrate leaching from grassland

    Science.gov (United States)

    Cuttle, S. P.; Scholefield, D.

    1995-12-01

    Nitrate leaching can be reduced by the adoption of less intensive grassland systems which, though requiring a greater land area to achieve the same agricultural output, result in less nitrate leaching per unit of production than do intensively managed grasslands. The economic penalties associated with reductions in output can be partly offset by greater reliance on symbiotic nitrogen fixation and the use of clover-based swards in place of synthetic N fertilisers. Alternatively, specific measures can be adopted to improve the efficiency of nitrogen use in intensively managed systems in order to maintain high outputs but with reduced losses. Controls should take account of other forms of loss and flows of nitrogen between grassland and other components of the whole-farm system and, in most instances, should result in an overall reduction in nitrogen inputs. Removing stock from the fields earlier in the grazing season will reduce the accumulation of high concentrations of potentially leachable nitrate in the soil of grazed pastures but will increase the quantity of manure produced by housed animals and the need to recycle this effectively. Supplementing grass diets with low-nitrogen forages such as maize silage will reduce the quantity of nitrogen excreted by livestock but may increase the potential for nitrate leaching elsewhere on the farm if changes to cropping patterns involve more frequent cultivation of grassland. Improved utilisation by the sward of nitrogen in animal excreta and manures and released by mineralisation of soil organic matter will permit equivalent reductions to be made in fertiliser inputs, provided that adequate information is available about the supply of nitrogen from these non-fertiliser sources.

  10. Nitrite and Nitrate Removal Efficiencies of Soil Aquifer Treatment Columns

    OpenAIRE

    GÜNGÖR, Kerem; ÜNLÜ, Kahraman

    2005-01-01

    Bench-scale soil column experiments were performed to examine the effects of soil type and infiltration conditions on the removal efficiencies of wastewater nitrites and nitrates during the biological ripening phase of soil aquifer treatment (SAT) columns. SAT was simulated in three 1-m-high soil columns packed with 3 different natural agricultural soils having sandy clay loam (SCL), loamy sand (LS) and sandy loam (SL) textures. All columns were equipped with tensiometers and soil-wa...

  11. Nitrate contamination of groundwater as a factor of atmospheric pollution

    International Nuclear Information System (INIS)

    High nitrate concentrations of ground water in agricultural regions not only enhance denitrification in gravel pit lakes but also increase the proportion of nitrous oxide (N2O) in the gaseous products released to the atmosphere. Thereby they contribute to the greenhouse effect and destruction of the stratospheric ozone layer. However, due to the present small area of the lakes, their effect may be considered as important at the global scale

  12. Corrosion performance of several metals in plutonium nitrate solution

    International Nuclear Information System (INIS)

    Corrosion behavior of several metals exposed in plutonium nitrate solution was studied. Plutonium nitrate solution with the plutonium concentration ranging from 0.01 to 300 g/l was used as a corrosive medium. Specimens tested were type 304 ULC (304 ULC) stainless steel, type 310 Nb (310 Nb) stainless steel, titanium (Ti), titanium-5% tantalum alloy (Ti-5Ta), and zirconium (Zr). Corrosion behavior of these metals in plutonium nitrate solution was evaluated through examining electrochemical characteristics and corrosion rates obtained by weight loss measurement. From the results of the corrosion tests, it was found that the corrosion rate of stainless steels i.e. 304 ULC and 310 Nb, increases by the presence of plutonium in nitric acid solution. The corrosion potential of the stainless steels shifted linearly towards the noble direction as the concentration of plutonium increases. It is thought that the shifts in corrosion potential of the stainless steels to the noble direction results an increase in anodic current and, hence, corrosion rate. Valve metals, i.e. Ti, Ti-5Ta and Zr, showed good corrosion resistance over the whole range of plutonium concentration examined here. (author)

  13. Groundwater pollution by nitrates in irrigated areas with drainage

    International Nuclear Information System (INIS)

    Field studies were conducted at three selected sites in irrigated areas of Pakistan to assess magnitude and severity of groundwater pollution by nitrates. The results of these studies indicate that concentration of nitrates in most of the samples collected from irrigated areas having drainage facility is much lower than threshold limit. The nitrate-nitrogen level within drainage projects ranges from 0.01-9.00 mg/l and in the area without drainage system ranges from 10.1-12.5 mg/l. The mineral fertilizers though are making contribution of NO3-N to the groundwater sources but that is much lower than threshold limits. The presence of septic tanks or farmyard manure dumps is also significant contributors of NO3-N to the groundwater. Thus drinking water sources near these polluting points are probable danger to human health. It is, therefore, concluded that still there is a lot of potential for fertilizer use in the agriculture but proper drainage facilities should be provided to minimize the potential threat of NO/sub 3/ pollution. (author)

  14. Optimisation of nitrate reductase enzyme activity to synthesise silver nanoparticles.

    Science.gov (United States)

    Khodashenas, Bahareh; Ghorbani, Hamid Reza

    2016-06-01

    Today, the synthesis of silver nanoparticles (Ag NPs) is very common since it has many applications in different areas. The synthesis of these nanoparticles is done by means of physical, chemical, or biological methods. However, due to its inexpensive and environmentally friendly features, the biological method is more preferable. In the present study, using nitrate reductase enzyme available in the Escherichia coli (E. coli) bacterium, the biosynthesis of Ag NPs was investigated. In addition, the activity of the nitrate reductase enzyme was optimised by changing its cultural conditions, and the effects of silver nitrate (AgNO3) concentration and enzyme amount on nanoparticles synthesis were studied. Finally, the produced nanoparticles were studied using ultraviolet -visible (UV-Vis) spectrophotometer, dynamic light scattering technique, and transmission electron microscopy. UV-Visible spectrophotometric study showed the characteristic peak for Ag NPs at wavelength 405-420 nm for 1 mM metal precursor solution (AgNO3) with 1, 5, 10, and 20 cc supernatant and 435 nm for 0.01M AgNO3 with 20 cc supernatant. In this study, it was found that there is a direct relationship between the AgNO3 concentration and the size of produced Ag NPs. PMID:27256897

  15. Studies on catalytic reduction of nitrate in groundwater

    Institute of Scientific and Technical Information of China (English)

    GENG Bing; ZHU Yanfang; JIN Zhaohui; LI Tielong; KANG Haiyan; WANG Shuaima

    2007-01-01

    Catalytic reduction of nitrate in groundwater by sodium formate over the catalyst was investigated.Pd-Cu/γ-Al2O3 catalyst was prepared by impregnation and characterized by brunauer-emmett-teller (BET),inductive coupled plasma (ICP),X-ray diffraction (XRD),transmission electron microscopy (TEM) and energy dispersive X-ray (EDX).It was found that total nitrogen was effectively removed from the nitrate solution (100 mg/L) and the removal efficiency was 87%.The catalytic activity was affected by pH,catalyst amount used,concentration of sodium formate,and initial concentration of nitrate.As sodium formate was used as reductant,precise control in the initial pH was needed.Excessively high or low initial pH (7.0 or 3.0) reduced catalytic activity.At initial pH of 4.5,catalytic activity was enhanced by reducing the amount of catalyst,while concentrations of sodium formate increased with a considerable decrease in N2 selectivity.In which case,catalytic reduction followed the first order kinetics.

  16. Precipitation of nitrate-cancrinite in Hanford Tank Sludge.

    Science.gov (United States)

    Buck, E C; McNamara, B K

    2004-08-15

    The chemistry of underground storage tanks containing high-level waste at the Hanford Site in Washington State is an area of continued research interest. Thermodynamic models have predicted the formation of analcime and clinoptilolite in Hanford tanks, rather than cancrinite; however, these predictions were based on carbonate-cancrinite. We report the first observation of a nitrate-cancrinite [possibly Na8(K,Cs)(AlSiO4)6(NO3)2 x nH2O] extracted from a Hanford tank 241-AP-101 sample that was evaporated to 6, 8, and 10 M NaOH concentrations. The nitrate-cancrinite phase formed spherical aggregates (4 microm in diameter) that consisted of platy hexagonal crystals (approximately 0.2 microm thick). Cesium-137 was concentrated in these aluminosilicate structures. These phases possessed a morphology identical to that of nitrate-cancrinite synthesized using simulant tests of nonradioactive tank waste, supporting the contention that it is possible to develop nonradioactive artificial sludges. This investigation points to the continued importance of understanding the solubility of NO3-cancrinite and related phases. Knowledge of the detailed structure of actual phases in the tank waste helps with thermodynamic modeling of tank conditions and waste processing. PMID:15382874

  17. Transition Metal Carbohydrazide Nitrates: Burn-rate Modifiers for Propellants

    Directory of Open Access Journals (Sweden)

    S. H. Sonawane

    2006-07-01

    Full Text Available This paper discusses the synthesis and characterisation of cobalt (Co, nickel (Ni andcopper (Cu carbohydrazide nitrates. In differential scanning calorimetry (DSC, the complexesexhibited exothermic decomposition indicating their energetic nature. The commencement ofdecomposition was observed at 220 °C for Ni complex, and at 160 °C for Co complex whereasthat of Cu complex occurred at 75 °C. In view of the better thermal stability, Ni and Co complexeswere selected for further study. The activation energy of decomposition of Ni and Co complexeswere found to be 47 kcal/mol and 60 kcal/mol respectively. Impact and friction sensitivity testresults revealed relatively lower vulnerability of carbohydrazide cobalt nitrate. Its incorporationin an ammonium perchlorate (AP-based composite propellant led to 9-19 per cent enhancementwhereas that of carbohydrazide nickel nitrate resulted in 28-74 per cent enhancement in burningrates in the pressure range 1.9 MPa to 8.8 MPa. Exothermic decomposition of the coordinationcomplexes on propellant surface and involvement of metal at molecular level formed ondecomposition of the complexes in combustion environment of composite propellant may beattributed to the catalytic effect of this class of compounds on the lines of reported literature.

  18. Biosensors Used for Quantification of Nitrates in Plants

    Directory of Open Access Journals (Sweden)

    Romero-Galindo Raul

    2016-01-01

    Full Text Available Nitrogen is essential for the plant because it is used for the production of chlorophyll, proteins, nucleic acids, amino acids, and other cellular compounds; nitrogen is available in two forms: ammonium and nitrate. Several tools have been used to quantify nitrates in plants such as the Kjeldahl method and Dumas combustion digestion; however, they are destructive and long time-consuming methods. To solve these disadvantages, methods such as selective electrodes, optical sensors, reflectometers, and images based sensors have been developed; nonetheless, all these techniques show interference when carrying out measurements. Currently, biosensors based on genetic constructions, based on the response of promoter gene fused to Gene Fluorescent Protein (GFP, are gaining popularity, because they improve the accuracy of measurements of nitrate by avoiding the interference of carriers ion, high salt conditions, and other factors. The present review shows the different methods to quantify the nitrogen in plants; later, a biosensors perspective is presented, mainly focused on biosensors based on organism genetically modified. The review presents a list of promoter and reporter genes that could be used to develop different kind of sensors, and a perspective of sensors to measure quantitatively the nitrogen is presented.

  19. Tandem electrochemical desalination-potentiometric nitrate sensing for seawater analysis.

    Science.gov (United States)

    Cuartero, Maria; Crespo, Gastón A; Bakker, Eric

    2015-08-18

    We report on a methodology for the direct potentiometric determination of nitrate in seawater by in-line coupling to an electrochemical desalination module. A microfluidic custom-fabricated thin layer flat cell allows one to electrochemically reduce the chloride concentration of seawater more than 100-fold, from 600 mM down to ∼2.8 mM. The desalinator operates by the exhaustive electrochemical plating of the halides from the thin layer sample onto a silver element as silver chloride, which is coupled to the transfer of the counter cations across a permselective ion-exchange membrane to an outer solution. As a consequence of suppressing the major interference of an ion-exchanger based membrane, the 80 μL desalinated sample plug is passed to a potentiometric flow cell of 13 μL volume. The potentiometric sensor is composed of an all-solid-state nitrate selective electrode based on lipophilic carbon nanotubes (f-MWCNTs) as an ion-to-electron transducer (slope of -58.9 mV dec(-1), limit of detection of 5 × 10(-7) M, and response time of 5 s in batch mode) and a miniaturized reference electrode. Nitrate is successfully determined in desalinated seawater using ion chromatography as the reference method. It is anticipated that this concept may form an attractive platform for in situ environmental analysis of a variety of ions that normally suffer from interference by the high saline level of seawater. PMID:26201537

  20. Design of one evaporation system for uranyl nitrate solution

    International Nuclear Information System (INIS)

    The authors propose an instant evaporation system with recirculation of the concentrated solution to raise the concentration from 50 to 1500 g of uranium per litre of solution. The capacity of the plant is to be 14.1 kg of uranium per hour. The main equipment used in the system is as follows: 1. Ring-type heat exchanger, for increasing the temperature of the mixture of fresh and recirculated solution from 80 to 1150C; 2. Separation tank, in which instant evaporation is carried out. The absolute pressure inside the tank will be 500 mmHg, with steam separation from a concentrated (78.5 wt.%) uranyl nitrate solution; 3. Desuperheater-condenser of horizontal tubular type for condensing water vapour and recovering any uranyl nitrate that may have been entrained; 4. Storage tank for the concentrate, with a capacity for one day's normal operation, and a heating coil to prevent crystallization of the concentrated solution; 5. Two storage tanks for feed and condensate with capacity for one day's normal operation; 6. Supporting structure for the above components. Virtually all equipment in contact with the uranyl nitrate solution will be made of 304 stainless steel. Saturated steam at 143.30C will be required. The cost of the proposed system is $543 030.00. (author)

  1. Neurobehavioral Assessment of Rats Exposed to Yttrium Nitrate during Development

    Institute of Scientific and Technical Information of China (English)

    LI Chen Xi; MA Chuan; FANG Hai Qin; ZHI Yuan; YU Zhou; XU Hai Bin; JIA Xu Dong

    2015-01-01

    Objective The aim of this study was to assess the effects of yttrium nitrate on neurobehavioral development in Sprague-Dawley rats. Methods Dams were orally exposed to 0, 5, 15, or 45 mg/kg daily of yttrium nitrate from gestation day (GD) 6 to postnatal day (PND) 21. Body weight and food consumption were monitored weekly. Neurobehavior was assessed by developmental landmarks and reflexes, motor activity, hot plate, Rota-rod and cognitive tests. Additionally, brain weights were measured on PND 21 and 70. Results No significant difference was noted among all groups for maternal body weight and food consumption. All yttrium-exposed offspring showed an increase in body weight on PND 21;however, no significant difference in body weight for exposed pups versus controls was observed 2 weeks or more after the yttrium solution was discontinued. The groups given 5 mg/kg daily decreased significantly in the duration of female forelime grip strength and ambulation on PND 13. There was no significant difference between yttrium-exposed offspring and controls with respect to other behavioral ontogeny parameters and postnatal behavioral test results. Conclusion Exposure of rats to yttrium nitrate in concentrations up to 45 mg/kg daily had no adverse effects on their neurobehavioral development.

  2. Laboratory studies of nitrate radical chemistry - application to atmospheric processes

    Energy Technology Data Exchange (ETDEWEB)

    Noremsaune, Ingse

    1997-12-31

    This thesis studies atmospheric chemistry and tries in particular to fill gaps in the data base of atmospheric reactions. It studies the nitrate radical reactions with chloroethenes and with but-2-yne (2-butyne). The mechanisms and rate coefficients for the NO{sub 3}-initiated degradation of the chloroethenes and 2-butyne were investigated by means of the static reaction chamber and the fast flow-discharge technique. The reactions between the nitrate radical and the chloroethenes were studied at atmospheric pressure in a reaction chamber with synthetic air as bath gas. FTIR (Fourier Transform InfraRed spectroscopy) spectroscopy was used to follow the reactions and to identify the products. Products were observed for the reactions with (E)-1,2-dichloroethene and tetrachloroethene, although the absorption bands are weak. The alkyl peroxynitrate and nitrate compounds form very strong and characteristic absorption bands. The rate coefficients for the reactions between NO{sub 3} and the chloroethenes were investigated at room temperature by three different methods. The results are given in tables. 132 refs., 44 figs., 21 tabs.

  3. Lightweight Magnetic Cooler With a Reversible Circulator

    Science.gov (United States)

    Chen, Weibo; McCormick, John

    2011-01-01

    A design of a highly efficient and lightweight space magnetic cooler has been developed that can continuously provide remote/distributed cooling at temperatures in the range of 2 K with a heat sink at about 15 K. The innovative design uses a cryogenic circulator that enables the cooler to operate at a high cycle frequency to achieve a large cooling capacity. The ability to provide remote/distributed cooling not only allows flexible integration with a payload and spacecraft, but also reduces the mass of the magnetic shields needed. The active magnetic regenerative refrigerator (AMRR) system is shown in the figure. This design mainly consists of two identical magnetic regenerators surrounded by their superconducting magnets and a reversible circulator. Each regenerator also has a heat exchanger at its warm end to reject the magnetization heat to the heat sink, and the two regenerators share a cold-end heat exchanger to absorb heat from a cooling target. The circulator controls the flow direction, which cycles in concert with the magnetic fields, to facilitate heat transfer. Helium enters the hot end of the demagnetized column, is cooled by the refrigerant, and passes into the cold-end heat exchanger to absorb heat. The helium then enters the cold end of the magnetized column, absorbing heat from the refrigerant, and enters the hot-end heat exchanger to reject the magnetization heat. The efficient heat transfer in the AMRR allows the system to operate at a relatively short cycle period to achieve a large cooling power. The key mechanical components in the magnetic cooler are the reversible circulator and the magnetic regenerators. The circulator uses non-contacting, self-acting gas bearings and clearance seals to achieve long life and vibration- free operation. There are no valves or mechanical wear in this circulator, so the reliability is predicted to be very high. The magnetic regenerator employs a structured bed configuration. The core consists of a stack of thin

  4. The stability of the thermohaline circulation in a coupled ocean-atmosphere general circulation model

    Energy Technology Data Exchange (ETDEWEB)

    Schiller, A. [Max-Planck-Institut fuer Meteorologie, Hamburg (Germany); Mikolajewicz, U. [Max-Planck-Institut fuer Meteorologie, Hamburg (Germany); Voss, R. [Deutsches Klimarechenzentrum (DKRZ), Hamburg (Germany)

    1996-02-01

    The stability of the Atlantic thermohaline circulation against meltwater input is investigated in a coupled ocean-atmosphere general circulation model. The meltwater input to the Labrador Sea is increased linearly for 250 years to a maximum input of 0.625 Sv and then reduced again to 0 (both instantaneously and slowly decreasing over 250 years). The resulting freshening forces a shutdown of the formation of North Atlantic deepwater and a subsequent reversal of the thermohaline circulation of the Atlantic, filling the deep Atlantic with Antarctic bottom water. The change in the overturning pattern causes a drastic reduction of the Atlantic northward heat transport, resulting in a strong cooling with maximum amplitude over the northern North Atlantic and a southward shift of the sea-ice margin in the Atlantic. Due to the increased meridional temperature gradient, the Atlantic intertropical convergence zone is displaced southward and the westerlies in the northern hemisphere gain strength. We identify four main feedbacks affecting the stability of the thermohaline circulation: the change in the overturning circulation of the Atlantic leads to longer residence times of the surface waters in high northern latitudes, which allows them to accumulate more precipitation and runoff from the continents, which results in an increased stability in the North Atlantic.

  5. Seasonal overturning circulation in the Red Sea: 1. Model validation and summer circulation

    KAUST Repository

    Yao, Fengchao

    2014-04-01

    The overturning circulation in the Red Sea exhibits a distinct seasonally reversing pattern and is studied using high-resolution MIT general circulation model simulations. In the first part of this study, the vertical and horizontal structure of the summer overturning circulation and its dynamical mechanisms are presented from the model results. The seasonal water exchange in the Strait of Bab el Mandeb is successfully simulated, and the structures of the intruding subsurface Gulf of Aden intermediate water are in good agreement with summer observations in 2011. The model results suggest that the summer overturning circulation is driven by the combined effect of the shoaling of the thermocline in the Gulf of Aden resulting from remote winds in the Arabian Sea and an upward surface slope from the Red Sea to the Gulf of Aden set up by local surface winds in the Red Sea. In addition, during late summer two processes associated, respectively, with latitudinally differential heating and increased salinity in the southern Red Sea act together to cause the reversal of the contrast of the vertical density structure and the cessation of the summer overturning circulation. Dynamically, the subsurface northward pressure gradient force is mainly balanced by vertical viscosity resulting from the vertical shear and boundary friction in the Strait of Bab el Mandeb. Unlike some previous studies, the three-layer summer exchange flows in the Strait of Bab el Mandeb do not appear to be hydraulically controlled.

  6. Explicit Determinants of the RFPrLrR Circulant and RLPrFrL Circulant Matrices Involving Some Famous Numbers

    Directory of Open Access Journals (Sweden)

    Tingting Xu

    2014-01-01

    Full Text Available Circulant matrices may play a crucial role in solving various differential equations. In this paper, the techniques used herein are based on the inverse factorization of polynomial. We give the explicit determinants of the RFPrLrR circulant matrices and RLPrFrL circulant matrices involving Fibonacci, Lucas, Pell, and Pell-Lucas number, respectively.

  7. Observation of nitrate coatings on atmospheric mineral dust particles

    Directory of Open Access Journals (Sweden)

    W. J. Li

    2009-03-01

    Full Text Available Nitrate compounds have received much attention because of their ability to alter the hygroscopic properties and cloud condensation nuclei (CCN activity of mineral dust particles in the atmosphere. However, very little is known about specific characteristics of ambient nitrate-coated mineral particles on an individual particle scale. In this study, sample collection was conducted during brown haze and dust episodes between 24 May and 21 June 2007 in Beijing, northern China. Sizes, morphologies, and compositions of 332 mineral dust particles together with their coatings were analyzed using transmission electron microscopy (TEM coupled with energy-dispersive X-ray (EDX microanalyses. Structures of some mineral particles were verified using selected-area electron diffraction (SAED. TEM observation indicates that approximately 90% of the collected mineral particles are covered by visible coatings in haze samples whereas only 5% are coated in the dust sample. 92% of the analyzed mineral particles are covered with Ca-, Mg-, and Na-rich coatings, and 8% are associated with K- and S-rich coatings. The majority of coatings contain Ca, Mg, O, and N with minor amounts of S and Cl, suggesting that they are possibly nitrates mixed with small amounts of sulfates and chlorides. These nitrate coatings are strongly correlated with the presence of alkaline mineral components (e.g., calcite and dolomite. CaSO4 particles with diameters from 10 to 500 nm were also detected in the coatings including Ca(NO32 and Mg(NO32. Our results indicate that mineral particles in brown haze episodes were involved in atmospheric heterogeneous reactions with two or more acidic gases (e.g., SO2, NO2, HCl, and HNO3. Mineral particles that acquire hygroscopic nitrate coatings tend to be more spherical and larger, enhancing their light scattering and CCN activity, both of which have cooling effects on

  8. Nitrate source apportionment in a subtropical watershed using Bayesian model

    International Nuclear Information System (INIS)

    Nitrate (NO3−) pollution in aquatic system is a worldwide problem. The temporal distribution pattern and sources of nitrate are of great concern for water quality. The nitrogen (N) cycling processes in a subtropical watershed located in Changxing County, Zhejiang Province, China were greatly influenced by the temporal variations of precipitation and temperature during the study period (September 2011 to July 2012). The highest NO3− concentration in water was in May (wet season, mean ± SD = 17.45 ± 9.50 mg L−1) and the lowest concentration occurred in December (dry season, mean ± SD = 10.54 ± 6.28 mg L−1). Nevertheless, no water sample in the study area exceeds the WHO drinking water limit of 50 mg L−1 NO3−. Four sources of NO3− (atmospheric deposition, AD; soil N, SN; synthetic fertilizer, SF; manure and sewage, M and S) were identified using both hydrochemical characteristics [Cl−, NO3−, HCO3−, SO42−, Ca2+, K+, Mg2+, Na+, dissolved oxygen (DO)] and dual isotope approach (δ15N–NO3− and δ18O–NO3−). Both chemical and isotopic characteristics indicated that denitrification was not the main N cycling process in the study area. Using a Bayesian model (stable isotope analysis in R, SIAR), the contribution of each source was apportioned. Source apportionment results showed that source contributions differed significantly between the dry and wet season, AD and M and S contributed more in December than in May. In contrast, SN and SF contributed more NO3− to water in May than that in December. M and S and SF were the major contributors in December and May, respectively. Moreover, the shortcomings and uncertainties of SIAR were discussed to provide implications for future works. With the assessment of temporal variation and sources of NO3−, better agricultural management practices and sewage disposal programs can be implemented to sustain water quality in subtropical watersheds. - Highlights: • Nitrate concentration in water displayed

  9. Effect of vegetation on the Late Miocene ocean circulation

    Directory of Open Access Journals (Sweden)

    G. Lohmann

    2006-08-01

    Full Text Available A weak and shallow thermohaline circulation in the North Atlantic Ocean is related to an open Central American gateway and exchange with fresh Pacific waters. We estimate the effect of vegetation on the ocean general circulation using the atmospheric circulation model simulations for the Late Miocene climate. Caused by an increase in net evaporation in the Miocene North Atlantic, the North Atlantic water becomes more saline which enhances the overturning circulation and thus the northward heat transport. This effect reveals a potentially important feedback between the ocean circulation, the hydrological cycle and the land surface cover for Cenozoic climate evolution.

  10. Foliar Application of Potassium Nitrate Affects the Growth and Nitrate Reductase Activity in Sunflower and Safflower Leaves under Salinity

    Directory of Open Access Journals (Sweden)

    Nusrat JABEEN

    2011-11-01

    Full Text Available Effect of foliar application of KNO3 on growth and the activity of nitrate reductase were studied in the leaves of sunflower (Helianthus annuus L. and safflower (Carthamus tinctorius L. plants growing under different levels of salinity. The seeds were sown in pots under non saline condition and saline water irrigation was started at three leaf stage after germination. Different concentration of saline water (i.e. 0.3% and 0.6%, equivalent to an EC of 4.8 and 8.6 dS/m respectively were made by dissolving sea salt per litre of tap water. Nutrient solution of KNO3 was sprayed at the rate of 250 ppm. The concentration of Na+ and Cl- rapidly increased in the leaves of both the plants under salinity stress. In contrast the nitrate (NO3- and soluble protein concentration were decreased with the increasing salinity. Salinity reduced leaf area, its fresh and dry weight per plant and also inhibited the activity of Nitrate reductase (NRA enzyme. The application of KNO3 significantly reduced the increasing tendency of Na+ and Cl- and increased leaf area, its fresh and dry weight per plant, NO3- and soluble protein concentration and NR activity in leaves irrespective to the growth of plant under non saline or saline conditions.

  11. The Extraction of Uranium as Uranyl Nitrate Complex in The Nitrate Acid Solution by Liquid Membrane Emulsion Technique

    International Nuclear Information System (INIS)

    The extraction of uranium as uranyl nitrate complex in the nitrate acid solution has been carried out using a liquid membrane emulsion technique. The liquid membrane phase is in form of emulsion that consists of kerosene as the solvent, sorbitan monooleat (span-80) as the surfactant, di-2 ethyl phosphoric acids (D2EHPA) as the carrier agent, and phosphoric acids as the internal phase. The optimum conditions for the extraction of uranium as uranyl nitrate complex have been obtained as the following: the organic phase (O) and the water or internal liquid phase (W) ratio in the liquid membrane phase (O/W) was 1, the concentration of nitric acid in the external phase was 3M, the D2EHPH concentration was 10% (v/v), the extraction time was 5 minutes and the agitation speed to achieve a membrane emulsion was 7500 rpm. At this condition the extraction efficiency obtained was 94.24%. The experiments also showed that the amount of extracted uranium by the liquid. membrane emulsion was limited

  12. 'Low-acid' sulfide oxidation using nitrate-enriched groundwater

    Science.gov (United States)

    Donn, Michael; Boxall, Naomi; Reid, Nathan; Meakin, Rebecca; Gray, David; Kaksonen, Anna; Robson, Thomas; Shiers, Denis

    2016-04-01

    Acid drainage (AMD/ARD) is undoubtedly one of the largest environmental, legislative and economic challenges facing the mining industry. In Australia alone, at least 60m is spent on AMD related issues annually, and the global cost is estimated to be in the order of tens of billions US. Furthermore, the challenge of safely and economically storing or treating sulfidic wastes will likely intensify because of the trend towards larger mines that process increasingly higher volumes of lower grade ores and the associated sulfidic wastes and lower profit margins. While the challenge of managing potentially acid forming (PAF) wastes will likely intensify, the industrial approaches to preventing acid production or ameliorating the effects has stagnated for decades. Conventionally, PAF waste is segregated and encapsulated in non-PAF tips to limit access to atmospheric oxygen. Two key limitations of the 'cap and cover' approach are: 1) the hazard (PAF) is not actually removed; only the pollutant linkage is severed; and, 2) these engineered structures are susceptible to physical failure in short-to-medium term, potentially re-establishing that pollutant linkage. In an effort to address these concerns, CSIRO is investigating a passive, 'low-acid' oxidation mechanism for sulfide treatment, which can potentially produce one quarter as much acidity compared with pyrite oxidation under atmospheric oxygen. This 'low-acid' mechanism relies on nitrate, rather than oxygen, as the primary electron accepter and the activity of specifically cultured chemolithoautotrophic bacteria and archaea communities. This research was prompted by the observation that, in deeply weathered terrains of Australia, shallow (oxic to sub-oxic) groundwater contacting weathering sulfides are commonly inconsistent with the geochemical conditions produced by ARD. One key characteristic of these aquifers is the natural abundance of nitrate on a regional scale, which becomes depleted around the sulfide bodies, and

  13. An 15N study of the effects of nitrate, ammonium, and nitrate + ammonium nutrition on nitrogen assimilation in Zea mays L

    International Nuclear Information System (INIS)

    A brief review of the literature on the effects of nitrate and ammonium nitrogen sources on plant growth, and the assimilation of those nitrogen sources, has been presented. It was concluded that ammonium nutrition produces optimum growth, with nitrate + ammonium being a better nitrogen source than only nitrate. Leaf blade nitrate reductase activity exceeded that of the root in nitrate-fed plants, suggesting that the shoot is the major region of nitrate assimilation. This is further supported by the results of xylem exudate analysis, where 93% of the newly-absorbed nitrogen exported by the roots was detected as nitrate. Evidence in support of this hypothesis was also obtained by studying the distribution of 15N in the various nitrogenous compounds. The effects of nitrogen source on plant growth, organic nitrogen and inorganic nitrogen contents, and the rates of incorporation into nitrogenous compounds were studied. The observed differences were explained with reference to the effects of the various nitrogen sources on the physiology of the plants. The experimental techniques included assays of the enzymes nitrate reductase and glutamine synthetase, whole plant growth studies, and the analysis of nitrogenous compounds of xylem exudate and those extracted from the leaf blade, leaf base, and root regions of maize plants after feeding with a nutrient solution containing nitrogen as 15N

  14. DROUGHT-INDUCED EFFECTS AND RECOVERY OF NITRATE ASSIMILATION AND NODULE ACTIVITY IN COWPEA PLANTS INOCULATED WITH BRADYRHIZOBIUM SPP. UNDER MODERATE NITRATE LEVEL

    Directory of Open Access Journals (Sweden)

    Silveira Joaquim Albenísio Gomes da

    2001-01-01

    Full Text Available This study was carried out to establish comparative effects of drought and recovery on the nitrate assimilation and nodule activity related to N2 fixation in cowpea plants [Vigna unguiculata L. (Walp.] previously inoculated with Bradyrhizobium spp. BR-3256 (CB-756 strain in the presence of 5 mol m-3 NO-3. Twenty-eight-day-old nodulated plants were submitted to water deprivation during 4 consecutive days and afterwards resupplied with nutrient solution during 2 days. The water deprivation caused a rapid increase in the nitrate content in root and a marked reduction in leaf nitrate reductase (NR activity. In contrast nodule NR activity was slightly increased by water deprivation. Concomitantly, in nodules of water stressed plants, leghemoglobin and glutamine synthetase (GS activity declined and a progressive reduction in ureide-N concentration in xylem sap was observed. Leaf-NR activity increased rapidly after rehydration while leaf nitrate content declined. In contrast both GS activity and soluble protein content in the nodule continued to decline in rewatered plants. In addition the concentration of leghemoglobin recovered well, while the xylem ureide-N content experienced a slight increase after rehydration. Despite the nitrate assimilation in leaves and the nodule activity had been both severely affected by water stress, the rapid recovery of nitrate reductase activity suggests that the nitrate assimilation process is less sensitive to drought/rehydration cycle when cowpea plants are nodulated in presence of moderate nitrate level.

  15. Elevated CO2-induced production of nitric oxide (NO) by NO synthase differentially affects nitrate reductase activity in Arabidopsis plants under different nitrate supplies.

    Science.gov (United States)

    Du, Shaoting; Zhang, Ranran; Zhang, Peng; Liu, Huijun; Yan, Minggang; Chen, Ni; Xie, Huaqiang; Ke, Shouwei

    2016-02-01

    CO2 elevation often alters the plant's nitrate reductase (NR) activity, the first enzyme acting in the nitrate assimilation pathway. However, the mechanism underlying this process remains unknown. The association between elevated CO2-induced alterations of NR activity and nitric oxide (NO) was examined in Col-0 Arabidopsis fed with 0.2-10 mM nitrate, using NO donors, NO scavenger, and NO synthase (NOS) inhibitor. The noa1 mutant, in which most NOS activity was lost, and the NR activity-null mutant nia1 nia2 were also used to examine the above association. In response to CO2 elevation, NR activity increased in low-nitrate Col-0 plants but was inhibited in high-nitrate Col-0 plants. NO scavenger and NOS inhibitor could eliminate these two responses, whereas the application of NO donors mimicked these distinct responses in ambient CO2-grown Col-0 plants. Furthermore, in both low- and high-nitrate conditions, elevated CO2 increased NOS activity and NO levels in Col-0 and nia1 nia2 plants but had little effect on NO level and NR activity in noa1 plants. Considering all of these findings, this study concluded that, in response to CO2 elevation, either the NR activity induction in low-nitrate plants or the NR activity inhibition in high-nitrate plants is regulated by NOS-generated NO. PMID:26608644

  16. Nitrate Did Wait. And It Looks Fabulous. The Nitrate Picture Show at the George Eastman House (Rochester, NY; May 1-3 2015

    Directory of Open Access Journals (Sweden)

    Sabrina Negri

    2015-07-01

    Full Text Available During The Nitrate Picture Show, nitrate prints were projected for an audience of archivists, scholars and cinephiles. This review will provide an account of the festival screenings, and will discuss the value of a festival of film conservation in the contemporary digital media landscape. 

  17. Gas cooled fast breeder reactor design for a circulator test facility (modified HTGR circulator test facility)

    Energy Technology Data Exchange (ETDEWEB)

    1979-10-01

    A GCFR helium circulator test facility sized for full design conditions is proposed for meeting the above requirements. The circulator will be mounted in a large vessel containing high pressure helium which will permit testing at the same power, speed, pressure, temperature and flow conditions intended in the demonstration plant. The electric drive motor for the circulator will obtain its power from an electric supply and distribution system in which electric power will be taken from a local utility. The conceptual design decribed in this report is the result of close interaction between the General Atomic Company (GA), designer of the GCFR, and The Ralph M. Parson Company, architect/engineer for the test facility. A realistic estimate of total project cost is presented, together with a schedule for design, procurement, construction, and inspection.

  18. Gas cooled fast breeder reactor design for a circulator test facility (modified HTGR circulator test facility)

    International Nuclear Information System (INIS)

    A GCFR helium circulator test facility sized for full design conditions is proposed for meeting the above requirements. The circulator will be mounted in a large vessel containing high pressure helium which will permit testing at the same power, speed, pressure, temperature and flow conditions intended in the demonstration plant. The electric drive motor for the circulator will obtain its power from an electric supply and distribution system in which electric power will be taken from a local utility. The conceptual design decribed in this report is the result of close interaction between the General Atomic Company (GA), designer of the GCFR, and The Ralph M. Parson Company, architect/engineer for the test facility. A realistic estimate of total project cost is presented, together with a schedule for design, procurement, construction, and inspection

  19. Atmospheric General Circulation Changes under Global Warming

    Science.gov (United States)

    Palipane, Erool

    The work in this thesis is mainly two-fold. First we study the internal variability of the general circulation and focus our study on the annular modes and how important it is to simulate the subsynoptic scales in the circulation. In the next major section we will try to understand the mechanisms of the forced response and the mechanisms leading towards the jet shift from transient evolution in Atmospheric general circulation models. In the first part, in an attempt to assess the benefit of resolving the sub-synoptic to mesoscale processes, the spatial and temporal characteristics of the Annular Modes (AMs), in particular those related to the troposphere-stratosphere interaction, are evaluated for moderate- and high-horizontal resolution simulations with a global atmospheric general circulation model (AGCM), in comparison with the ERA40 re- analysis. Relative to the CMIP-type climate models, the IFS AGCM demonstrates notable improvement in capturing the key characteristics of the AMs. Notably, the performance with the high horizontal resolution version of the model is systematically superior to the moderate resolution on all metrics examined, including the variance of the AMs at different seasons of the year, the intrinsic e-folding time scales of the AMs, and the downward influence from the stratosphere to troposphere in the AMs. Moreover, the high-resolution simulation with a greater persistence in the intrinsic variability of the SAM projects an appreciably larger shift of the surface westerly wind during the Southern Hemisphere summer under climate change. In the second part, the response of the atmospheric circulation to greenhouse gas-induced SST warming is investigated using large ensemble experiments with two AGCMs, with a focus on the robust feature of the poleward shift of the eddy driven jet. In these experiments, large ensembles of simulations are conducted by abruptly switching the SST forcing on from January 1st to focus on the wintertime circulation

  20. Interdependence of two NarK domains in a fused nitrate/nitrite transporter.

    Science.gov (United States)

    Goddard, Alan D; Moir, James W B; Richardson, David J; Ferguson, Stuart J

    2008-11-01

    Nitrate uptake is essential for various bacterial processes and combines with nitrite export to form the usual initial steps of denitrification, a process that reduces nitrate to dinitrogen gas. Although many bacterial species contain NarK-like transporters that are proposed to function as either nitrate/proton symporters or nitrate/nitrite antiporters based on sequence homology, these transporters remain, in general, poorly characterized. Several bacteria appear to contain a transporter that is a fusion of two NarK-like proteins, although the significance of this arrangement remains elusive. We demonstrate that NarK from Paracoccus denitrificans is expressed as a fusion of two NarK-like transporters. NarK1 and NarK2 are separately capable of supporting anaerobic denitrifying growth but with growth defects that are partially mitigated by coexpression of the two domains. NarK1 appears to be a nitrate/proton symporter with high affinity for nitrate and NarK2 a nitrate/nitrite antiporter with lower affinity for nitrate. Each transporter requires two conserved arginine residues for activity. A transporter consisting of inactivated NarK1 fused to active NarK2 has a dramatically increased affinity for nitrate compared with NarK2 alone, implying a functional interaction between the two domains. A potential model for nitrate and nitrite transport in P. denitrificans is proposed. PMID:18823285