Different cultivation methods to acclimatise ammonia-tolerant methanogenic consortia.

Science.gov (United States)

Tian, Hailin; Fotidis, Ioannis A; Mancini, Enrico; Angelidaki, Irini

2017-05-01

Bioaugmentation with ammonia tolerant-methanogenic consortia was proposed as a solution to overcome ammonia inhibition during anaerobic digestion process recently. However, appropriate technology to generate ammonia tolerant methanogenic consortia is still lacking. In this study, three basic reactors (i.e. batch, fed-batch and continuous stirred-tank reactors (CSTR)) operated at mesophilic (37°C) and thermophilic (55°C) conditions were assessed, based on methane production efficiency, incubation time, TAN/FAN (total ammonium nitrogen/free ammonia nitrogen) levels and maximum methanogenic activity. Overall, fed-batch cultivation was clearly the most efficient method compared to batch and CSTR. Specifically, by saving incubation time up to 150%, fed-batch reactors were acclimatised to nearly 2-fold higher FAN levels with a 37%-153% methanogenic activity improvement, compared to batch method. Meanwhile, CSTR reactors were inhibited at lower ammonia levels. Finally, specific methanogenic activity test showed that hydrogenotrophic methanogens were more active than aceticlastic methanogens in all FAN levels above 540mgNH 3 -NL -1 . Copyright © 2017 Elsevier Ltd. All rights reserved.

Method for application of nitrogen-15-labeled anhydrous ammonia to small plots

International Nuclear Information System (INIS)

Sanchez, C.A.; Blackmer, A.M.

1987-01-01

A method is described that permits precise application of anhydrous ammonia in bands to plots of the size often used in 15 N-tracer studies. This method involves placing a stainless-steel capillary tube in the soil where the ammonia is to be banded, attaching this tube to a cylinder of ammonia, and then pulling the tube through the soil with deposition of ammonia as an even band. The procedure has marked advantages over previously described methods because it can be used with mixtures of anhydrous ammonia and nitrification inhibitors and because the soil environment at the point of application is representative of the soil environment found when a conventional applicator is used

Assessment of research and development (R and D) needs in ammonia safety and environmental control

Energy Technology Data Exchange (ETDEWEB)

Brenchley, D.L.; Athey, G.F.; Bomelburg, H.J.

1981-09-01

This report characterizes the ammonia industry operations, reviews current knowledge of ammonia release and subsequent impacts, summarizes the status of release prevention and control methods and identify research and development needs for safety and environmental control. Appendices include: accidental spills and human exposure; adiabatic mixing of liquid nitrogen and air; fire and explosion hazards; and environmental impact rating tables. (PSB)

Method for the Determination of Ammonia in Mainstream Cigarette Smoke Using Ion Chromatography.

Directory of Open Access Journals (Sweden)

Christina Vaughan Watson

Full Text Available Ammonia in mainstream smoke is present in both the particulate and vapor phases. The presence of ammonia in the cigarette filler material and smoke is of significance because of the potential role ammonia could have in raising the "smoke pH." An increased smoke pH could shift a fraction of total nicotine to free-base nicotine, which is reportedly more rapidly absorbed by the smoker. Methods measuring ammonia in smoke typically employ acid filled impingers to trap the smoke. We developed a fast, reliable method to measure ammonia in mainstream smoke without the use of costly and time consuming impingers to examine differences in ammonia delivery. The method uses both a Cambridge filter pad and a Tedlar bag to capture particulate and vapor phases of the smoke. We quantified ammonia levels in the mainstream smoke of 50 cigarette brands from 5 manufacturers. Ammonia levels ranged from approximately 1μg to 23μg per cigarette for ISO smoking conditions and 38μg to 67μg per cigarette for Canadian intense smoking conditions and statistically significance differences were observed between brands and manufacturers. Our findings suggest that ammonia levels vary by brand and are higher under Canadian intense smoking conditions.

Surface - atmosphere exchange of ammonia over grazed pasture

NARCIS (Netherlands)

Plantaz, M.A.H.G.

1998-01-01

This thesis deals with the exchange of ammonia between the atmosphere and grazed pasture in an area of intensive livestock breeding. The term exchange is used because gaseous ammonia can be taken up (dry deposition) as well as released (emission) by this type of surface.
Ammonia exchange

Resveratrol prevents ammonia toxicity in astroglial cells.

Directory of Open Access Journals (Sweden)

Larissa Daniele Bobermin

Full Text Available Ammonia is implicated as a neurotoxin in brain metabolic disorders associated with hyperammonemia. Acute ammonia toxicity can be mediated by an excitotoxic mechanism, oxidative stress and nitric oxide (NO production. Astrocytes interact with neurons, providing metabolic support and protecting against oxidative stress and excitotoxicity. Astrocytes also convert excess ammonia and glutamate into glutamine via glutamine synthetase (GS. Resveratrol, a polyphenol found in grapes and red wines, exhibits antioxidant and anti-inflammatory properties and modulates glial functions, such as glutamate metabolism. We investigated the effect of resveratrol on the production of reactive oxygen species (ROS, GS activity, S100B secretion, TNF-α, IL-1β and IL-6 levels in astroglial cells exposed to ammonia. Ammonia induced oxidative stress, decreased GS activity and increased cytokines release, probably by a mechanism dependent on protein kinase A (PKA and extracellular signal-regulated kinase (ERK pathways. Resveratrol prevented ammonia toxicity by modulating oxidative stress, glial and inflammatory responses. The ERK and nuclear factor-κB (NF-κB are involved in the protective effect of resveratrol on cytokines proinflammatory release. In contrast, other antioxidants (e.g., ascorbic acid and trolox were not effective against hyperammonemia. Thus, resveratrol could be used to protect against ammonia-induced neurotoxicity.

Resveratrol Prevents Ammonia Toxicity in Astroglial Cells

Science.gov (United States)

Guerra, Maria Cristina; Leite, Marina Concli; Souza, Diogo Onofre; Gonçalves, Carlos-Alberto; Gottfried, Carmem

2012-01-01

Ammonia is implicated as a neurotoxin in brain metabolic disorders associated with hyperammonemia. Acute ammonia toxicity can be mediated by an excitotoxic mechanism, oxidative stress and nitric oxide (NO) production. Astrocytes interact with neurons, providing metabolic support and protecting against oxidative stress and excitotoxicity. Astrocytes also convert excess ammonia and glutamate into glutamine via glutamine synthetase (GS). Resveratrol, a polyphenol found in grapes and red wines, exhibits antioxidant and anti-inflammatory properties and modulates glial functions, such as glutamate metabolism. We investigated the effect of resveratrol on the production of reactive oxygen species (ROS), GS activity, S100B secretion, TNF-α, IL-1β and IL-6 levels in astroglial cells exposed to ammonia. Ammonia induced oxidative stress, decreased GS activity and increased cytokines release, probably by a mechanism dependent on protein kinase A (PKA) and extracellular signal-regulated kinase (ERK) pathways. Resveratrol prevented ammonia toxicity by modulating oxidative stress, glial and inflammatory responses. The ERK and nuclear factor-κB (NF-κB) are involved in the protective effect of resveratrol on cytokines proinflammatory release. In contrast, other antioxidants (e.g., ascorbic acid and trolox) were not effective against hyperammonemia. Thus, resveratrol could be used to protect against ammonia-induced neurotoxicity. PMID:23284918

Ammonia-free chemical bath method for deposition of microcrystalline cadmium selenide films

International Nuclear Information System (INIS)

Lokhande, C.D.; Lee, Eun-Ho; Jung, Kwang-Deog; Joo, Oh-Shim

2005-01-01

Chemical deposition of cadmium selenide (CdSe) films has been carried out from alkaline aqueous solution containing Cd 2+ and Se 2- ions. In general, the alkaline pH of the CdSe deposition bath has been adjusted by addition of liquid ammonia. However, the use of ammonia in large-scale chemical deposition method represents an environmental problem due to its volatility and toxicity. The volatility of ammonia changes the pH of deposition bath and results into irreproducible film properties. In the present paper, ammonia-free and weak alkaline (pH < 9.0) chemical method for cadmium selenide film has been developed. The cadmium selenide films are microcrystalline (grain size 0.5-0.7 μm) with hexagonal crystal structure. These films are photoactive and therefore, useful in photo conversion of light into electrical power

Ammonia removal from an aqueous solution and method for the production of a fertilizer material

NARCIS (Netherlands)

Kelder, E.M.; Ursem, W.N.J.; Roos, R.A.; Marijnissen, J.C.M.

2011-01-01

The invention provides method for the removal of ammonia from air and converting the ammonia in a fertilizer material, comprising (a) contacting at least part of the air with an aqueous liquid, wherein the aqueous liquid is a solvent for ammonia, to provide an ammonia containing aqueous

Applicability of Zeolite Based Systems for Ammonia Removal and Recovery From Wastewater.

Science.gov (United States)

Das, Pallabi; Prasad, Bably; Singh, Krishna Kant Kumar

2017-09-01

  Ammonia discharged in industrial effluents bears deleterious effects and necessitates remediation. Integrated systems devoted to recovery of ammonia in a useful form and remediation of the same addresses the challenges of waste management and its utilization. A comparative performance evaluation study was undertaken to access the suitability of different zeolite based systems (commercial zeolites and zeolites synthesized from fly ash) for removal of ammonia followed by its subsequent release. Four main parameters which were studied to evaluate the applicability of such systems for large scale usage are cost-effectiveness, ammonia removal efficiency, performance on regeneration, and ammonia release percentage. The results indicated that synthetic zeolites outperformed zeolites synthesized from fly ash, although the later proved to be more efficient in terms of total cost incurred. Process technology development in this direction will be a trade-of between cost and ammonia removal and release efficiencies.

Development of analytical method used for the estimation of potassium amide in liquid ammonia at HWP (Tuticorin)

International Nuclear Information System (INIS)

Ramanathan, A.V.

2007-01-01

Potassium amide in liquid ammonia is used as a homogeneous catalyst in mono-thermal ammonia-hydrogen isotopic chemical exchange process employed for the manufacture of heavy water. Estimation of concentration of potassium amide in liquid ammonia is vital for checking whether it is sufficient for catalysis in isotopic exchange towers or for purification in purifiers in the Heavy Water Plants. This estimation was carried out earlier by the conventional method involving evaporation of ammonia, decomposition of potassium amide with water and titration of liberated ammonia with sulphuric acid. This method has been replaced by a newly developed method involving direct titration of potassium amide in ammonia with ammonium bromide. This new method is based on the principle that ammonium bromide and potassium amide act as acid and base respectively in the non-aqueous solvent medium, liquid ammonia. This method has not only proved to be an alternative method of estimation of potassium amide in liquid ammonia but also has been serving as a developed analytical method, because it is faster (with fewer steps), more accurate, safer (as it excludes the use of corrosive sulphuric acid needed for the conventional method) and more convenient (as it doesn't need specially designed apparatus and inert gas like dry nitrogen used in the conventional method). (author)

Removal of ammonia from tarry water using a tubular furnace

Energy Technology Data Exchange (ETDEWEB)

V.V. Grabko; V.A. Kofanova; V.M. Li; M.A. Solov' ev [Giprokoks, the State Institute for the Design of Coke-Industry Enterprises, Kharkov (Ukraine)

2009-07-15

An ammonia-processing system without the use of live steam from OAO Alchevskkoks plant's supply network is considered. Steam obtained from the wastewater that leaves the ammonia column is used to process the excess tarry water, with the release of volatile ammonia.

Different cultivation methods to acclimatise ammonia-tolerant methanogenic consortia

DEFF Research Database (Denmark)

Tian, Hailin; Fotidis, Ioannis; Mancini, Enrico

2017-01-01

reactors (i.e. batch, fed-batch and continuous stirred-tank reactors (CSTR)) operated at mesophilic (37°C) and thermophilic (55°C) conditions were assessed, based on methane production efficiency, incubation time, TAN/FAN (total ammonium nitrogen/free ammonia nitrogen) levels and maximum methanogenic...... activity. Overall, fed-batch cultivation was clearly the most efficient method compared to batch and CSTR. Specifically, by saving incubation time up to 150%, fed-batch reactors were acclimatised to nearly 2-fold higher FAN levels with a 37%-153% methanogenic activity improvement, compared to batch method....... Meanwhile, CSTR reactors were inhibited at lower ammonia levels. Finally, specific methanogenic activity test showed that hydrogenotrophic methanogens were more active than aceticlastic methanogens in all FAN levels above 540 mg NH3-N L-1....

Treatment of reactive process wastewater with high-level ammonia by blow-off method

International Nuclear Information System (INIS)

Chen Xiaotong; Quan Ying; Wang Yang; Fu Genna; Liu Bing; Tang Yaping

2012-01-01

The ceramic UO 2 kernels for nuclear fuel elements of high temperature gas cooled reactors were prepared through sol-gel process with uranyl nitrate, which produces process wastewater containing high-level ammonia and uranium. The blow-off method on a bench scale was investigated to remove ammonia from reactive wastewater. Under the optimized operating conditions, the ammonia can be removed by more than 95%, with little reactive uranium distilled. The effects of pH, heating temperature and stripping time were studied. Static tests with ion-exchange resin indicate that ammonia removal treatment increases uranium accumulation in anion exchange resin. (authors)

Ammonia Released by Streptomyces aburaviensis Induces Droplet Formation in Streptomyces violaceoruber.

Science.gov (United States)

Schmidt, Kathrin; Spiteller, Dieter

2017-08-01

Streptomyces violaceoruber grown in co-culture with Streptomyces aburaviensis produces an about 17-fold higher volume of droplets on its aerial mycelium than in single-culture. Physical separation of the Streptomyces strains by either a plastic barrier or by a dialysis membrane, which allowed communication only by the exchange of volatile compounds or diffusible compounds in the medium, respectively, still resulted in enhanced droplet formation. The application of molecular sieves to bioassays resulted in the attenuation of the droplet-inducing effect of S. aburaviensis indicating the absorption of the compound. 1 H-NMR analysis of molecular-sieve extracts and the selective indophenol-blue reaction revealed that the volatile droplet-inducing compound is ammonia. The external supply of ammonia in biologically relevant concentrations of ≥8 mM enhanced droplet formation in S. violaceoruber in a similar way to S. aburaviensis. Ammonia appears to trigger droplet production in many Streptomyces strains because four out of six Streptomyces strains exposed to ammonia exhibited induced droplet production.

Gut does not contribute to systemic ammonia release in humans without portosystemic shunting

NARCIS (Netherlands)

van de Poll, Marcel C. G.; Ligthart-Melis, Gerdien C.; Damink, Steven W. M. Olde; van Leeuwen, Paul A. M.; Beets-Tan, Regina G. H.; Deutz, Nicolaas E. P.; Wigmore, Stephen J.; Soeters, Peter B.; Dejong, Cornelis H. C.

2008-01-01

The gut is classically seen as the main source of circulating ammonia. However, the contribution of the intestines to systemic ammonia production may be limited by hepatic extraction of portal-derived ammonia. Recent data suggest that the kidney may be more important than the gut for systemic

Ammonia Monitor

Science.gov (United States)

Sauer, Richard L. (Inventor); Akse, James R. (Inventor); Thompson, John O. (Inventor); Atwater, James E. (Inventor)

1999-01-01

Ammonia monitor and method of use are disclosed. A continuous, real-time determination of the concentration of ammonia in an aqueous process stream is possible over a wide dynamic range of concentrations. No reagents are required because pH is controlled by an in-line solid-phase base. Ammonia is selectively transported across a membrane from the process stream to an analytical stream to an analytical stream under pH control. The specific electrical conductance of the analytical stream is measured and used to determine the concentration of ammonia.

Ammonia causes decreased brain monoamines in fathead minnows (Pimephales promelas)

Science.gov (United States)

Ronan, Patrick J.; Gaikowski, Mark P.; Hamilton, Steven J.; Buhl, Kevin J.; Summers, Cliff H.

2007-01-01

Hyperammonemia, arising from variety of disorders, leads to severe neurological dysfunction. The mechanisms of ammonia toxicity in brain are not completely understood. This study investigated the effects of ammonia on monoaminergic systems in brains of fathead minnows (Pimephales promelas). Fish serve as a good model system to investigate hyperammonemic effects on brain function since no liver manipulations are necessary to increase endogenous ammonia concentrations. Using high performance liquid chromatography with electrochemical detection, monoamines and some associated metabolites were measured from whole brain homogenate. Adult males were exposed for 48 h to six different concentrations of ammonia (0.01–2.36 mg/l unionized) which bracketed the 96-h LC50 for this species. Ammonia concentration-dependent decreases were found for the catecholamines (norepinephrine and dopamine) and the indoleamine serotonin (5-HT). After an initial increase in the 5-HT precursor 5-hydroxytryptophan it too decreased with increasing ammonia concentrations. There were also significant increases in the 5-HIAA/5-HT and DOPAC/DA ratios, often used as measures of turnover. There were no changes in epinephrine (Epi) or monoamine catabolites (DOPAC, 5-HIAA) at any ammonia concentrations tested. Results suggest that ammonia causes decreased synthesis while also causing increased release and degradation. Increased release may underlie behavioral reactions to ammonia exposure in fish. This study adds weight to a growing body of evidence demonstrating that ammonia leads to dysfunctional monoaminergic systems in brain which may underlie neurological symptoms associated with human disorders such as hepatic encephalopathy.

Numerical Simulations of Airflow and Droplet Dispersion in a Horizontal Ammonia Scrubber

DEFF Research Database (Denmark)

Liu, Li; Nielsen, Peter Vilhelm; Heiselberg, Per Kvols

2015-01-01

Ammonia released in pig production industries can lead to eutrophication of surface waters, soil acidification, fertilization of vegetation and changes in ecosystems, etc. Air scrubbers with spray of aerosolized sulphur solution were used to remove the ammonia mixed in the airflow ventilated out...... plate or a flow straightener were tested. Impact of nozzle velocity and droplet residue size were analysed. It is found that additional input on the pump pressure to increase the injection velocity may not cause any more benefit in our cases, and the ammonia removal efficiency of the horizontal scrubber...... from a piggery. In this study, numerical method were used to investigate airflow pattern, droplet dispersion, ammonia absorption at droplet surface and overall removal efficiency in an air cleaner. Droplet trajectories and elapsed time in air were adopted to characterize the absorption efficiency...

Comparison of ammonia emissions determined using different sampling methods

Science.gov (United States)

Dynamic, flow-through flux chambers are sometimes used to estimate ammonia emissions from livestock operations; however, ammonia emissions from the surfaces are affected by many factors which can be affected by the chamber. Ammonia emissions estimated using environmental flow-through chambers may be...

AMMONIA IN THE EARLY SOLAR SYSTEM: AN ACCOUNT FROM CARBONACEOUS METEORITES

International Nuclear Information System (INIS)

Pizzarello, S.; Williams, L. B.

2012-01-01

This study presents a survey of abundance distribution and isotopic composition of the ammonia found incorporated in the kerogen-like insoluble material of selected carbonaceous chondrite meteorites; the ammonia was released upon hydrothermal treatment at 300°C and 100 MPa. With the exception of Allende, a metamorphosed and highly altered stone, all the insoluble organic materials (IOM) of the meteorites analyzed released significant amounts of ammonia, which varied from over 4 μg mg –1 for the Orgueil IOM to 0.5 μg mg –1 for that of Tagish Lake; the IOM of the pristine Antarctica find GRA95229 remains the most rich in freeable ammonia with 10 μg mg –1 . While the amounts of IOM bound ammonia do not appear to vary between meteorites with a recognizable trend, a possible consequence of long terrestrial exposure of some of the stones, we found that the δ 15 N composition of the ammonia-carrying materials is clearly distinctive of meteorite types and may reflect a preservation of the original 15 N distribution of pre- and proto-solar materials.

Ammonia in the Early Solar System: An Account from Carbonaceous Meteorites

Science.gov (United States)

Pizzarello, S.; Williams, L. B.

2012-04-01

This study presents a survey of abundance distribution and isotopic composition of the ammonia found incorporated in the kerogen-like insoluble material of selected carbonaceous chondrite meteorites; the ammonia was released upon hydrothermal treatment at 300°C and 100 MPa. With the exception of Allende, a metamorphosed and highly altered stone, all the insoluble organic materials (IOM) of the meteorites analyzed released significant amounts of ammonia, which varied from over 4 μg mg-1 for the Orgueil IOM to 0.5 μg mg-1 for that of Tagish Lake; the IOM of the pristine Antarctica find GRA95229 remains the most rich in freeable ammonia with 10 μg mg-1. While the amounts of IOM bound ammonia do not appear to vary between meteorites with a recognizable trend, a possible consequence of long terrestrial exposure of some of the stones, we found that the δ15N composition of the ammonia-carrying materials is clearly distinctive of meteorite types and may reflect a preservation of the original 15N distribution of pre- and proto-solar materials.

A simple and rapid visual method for the determination of ammonia nitrogen in environmental waters using thymol

Energy Technology Data Exchange (ETDEWEB)

Okumura, M.; Fujinaga, K.; Seike, Y.; Honda, S. [Dept. of Material Science, Interdisciplinary Faculty of Science and Engineering, Shimane University, Matsue (Japan)

1999-11-01

Simple visual and spectrophotometric methods for the determination of ammonia nitrogen in water are proposed, based on the color development of indothymol blue formed between ammonia and thymol. The color development was accelerated by nitroprusside to complete in 3 min. This color development is remarkably rapid compared with that of the other conventional methods with indothymol blue and indophenol blue. The concentration range of ammonia nitrogen spectrophotometrically determined was 0.04-1.2 mg/L NH{sub 4}-N. The absorbance per 1 {mu}g NH{sub 4}-N was 0.0215 (molar absorptivity = 1.51 x 10{sup 4}) at 690 nm. The visual method not using any instrument as an in situ method in field works was developed based on the optimum conditions for the established spectrophotometric method. This visual method was successfully applied to the determination of ammonia nitrogen in environmental waters. (orig.)

Ammonia complexes of metals in aqueous solutions with high concentrations of ammonia

International Nuclear Information System (INIS)

Padar, T.G.; Novikov, L.K.; Stupko, T.V.; Isaev, I.D.; Pashkov, G.L.; Mironov, V.E.

1991-01-01

Potentiometric method, glass electrodes and Bierrum function were used to study the formation of ammonia complexes of magnesium, calcium, cadmium, zinc, copper(2) and silver in 2.0 mol/dm 3 aqueous solutions of ammonia nitrate with 0-18 mol/dm 3 ammonia concentrations at 25.0 deg C. Step constants of stability of studied complexes were calculated and their compositions were determined with account of nonideal character of aqueous-salt solutions with ammonia concentrations above 1.0 mol/dm 3 . Values of correction effects on salting out ammonia action for Bierrum function in solutions with 1.0-18 mol/dm 3 ammonia concentrations were found

Use of zeolite for removing ammonia and ammonia-caused toxicity in marine toxicity identification evaluations.

Science.gov (United States)

Burgess, R M; Perron, M M; Cantwell, M G; Ho, K T; Serbst, J R; Pelletier, M C

2004-11-01

Ammonia occurs in marine waters including effluents, receiving waters, and sediment interstitial waters. At sufficiently high concentrations, ammonia can be toxic to aquatic species. Toxicity identification evaluation (TIE) methods provide researchers with tools for identifying aquatic toxicants. For identifying ammonia toxicity, there are several possible methods including pH alteration and volatilization, Ulva lactuca addition, microbial degradation, and zeolite addition. Zeolite addition has been used successfully in freshwater systems to decrease ammonia concentrations and toxicity for several decades. However, zeolite in marine systems has been used less because ions in the seawater interfere with zeolite's ability to adsorb ammonia. The objective of this study was to develop a zeolite method for removing ammonia from marine waters. To accomplish this objective, we performed a series of zeolite slurry and column chromatography studies to determine uptake rate and capacity and to evaluate the effects of salinity and pH on ammonia removal. We also assessed the interaction of zeolite with several toxic metals. Success of the methods was also evaluated by measuring toxicity to two marine species: the mysid Americamysis bahia and the amphipod Ampelisca abdita. Column chromatography proved to be effective at removing a wide range of ammonia concentrations under several experimental conditions. Conversely, the slurry method was inconsistent and variable in its overall performance in removing ammonia and cannot be recommended. The metals copper, lead, and zinc were removed by zeolite in both the slurry and column treatments. The zeolite column was successful in removing ammonia toxicity for both the mysid and the amphipod, whereas the slurry was less effective. This study demonstrated that zeolite column chromatography is a useful tool for conducting marine water TIEs to decrease ammonia concentrations and characterize toxicity.

[Study on Ammonia Emission Rules in a Dairy Feedlot Based on Laser Spectroscopy Detection Method].

Science.gov (United States)

He, Ying; Zhang, Yu-jun; You, Kun; Wang, Li-ming; Gao, Yan-wei; Xu, Jin-feng; Gao, Zhi-ling; Ma, Wen-qi

2016-03-01

It needs on-line monitoring of ammonia concentration on dairy feedlot to disclose ammonia emissions characteristics accurately for reducing ammonia emissions and improving the ecological environment. The on-line monitoring system for ammonia concentration has been designed based on Tunable Diode Laser Absorption Spectroscopy (TDLAS) technology combining with long open-path technology, then the study has been carried out with inverse dispersion technique and the system. The ammonia concentration in-situ has been detected and ammonia emission rules have been analyzed on a dairy feedlot in Baoding in autumn and winter of 2013. The monitoring indicated that the peak of ammonia concentration was 6.11 x 10(-6) in autumn, and that was 6.56 x 10(-6) in winter. The concentration results show that the variation of ammonia concentration had an obvious diurnal periodicity, and the general characteristic of diurnal variation was that the concentration was low in the daytime and was high at night. The ammonia emissions characteristic was obtained with inverse dispersion model that the peak of ammonia emissions velocity appeared at noon. The emission velocity was from 1.48 kg/head/hr to 130.6 kg/head/hr in autumn, and it was from 0.004 5 kg/head/hr to 43.32 kg/head/hr in winter which was lower than that in autumn. The results demonstrated ammonia emissions had certain seasonal differences in dairy feedlot scale. In conclusion, the ammonia concentration was detected with optical technology, and the ammonia emissions results were acquired by inverse dispersion model analysis with large range, high sensitivity, quick response without gas sampling. Thus, it's an effective method for ammonia emissions monitoring in dairy feedlot that provides technical support for scientific breeding.

Mathematical Model of Ammonia Handling in the Rat Renal Medulla

Science.gov (United States)

Noiret, Lorette; Baigent, Stephen; Jalan, Rajiv; Thomas, S. Randall

2015-01-01

The kidney is one of the main organs that produces ammonia and release it into the circulation. Under normal conditions, between 30 and 50% of the ammonia produced in the kidney is excreted in the urine, the rest being absorbed into the systemic circulation via the renal vein. In acidosis and in some pathological conditions, the proportion of urinary excretion can increase to 70% of the ammonia produced in the kidney. Mechanisms regulating the balance between urinary excretion and renal vein release are not fully understood. We developed a mathematical model that reflects current thinking about renal ammonia handling in order to investigate the role of each tubular segment and identify some of the components which might control this balance. The model treats the movements of water, sodium chloride, urea, NH3 and NH4+, and non-reabsorbable solute in an idealized renal medulla of the rat at steady state. A parameter study was performed to identify the transport parameters and microenvironmental conditions that most affect the rate of urinary ammonia excretion. Our results suggest that urinary ammonia excretion is mainly determined by those parameters that affect ammonia recycling in the loops of Henle. In particular, our results suggest a critical role for interstitial pH in the outer medulla and for luminal pH along the inner medullary collecting ducts. PMID:26280830

AMMONIA IN THE EARLY SOLAR SYSTEM: AN ACCOUNT FROM CARBONACEOUS METEORITES

Energy Technology Data Exchange (ETDEWEB)

Pizzarello, S. [Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ 85287-1604 (United States); Williams, L. B., E-mail: pizzar@asu.edu [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287-1404 (United States)

2012-04-20

This study presents a survey of abundance distribution and isotopic composition of the ammonia found incorporated in the kerogen-like insoluble material of selected carbonaceous chondrite meteorites; the ammonia was released upon hydrothermal treatment at 300 Degree-Sign C and 100 MPa. With the exception of Allende, a metamorphosed and highly altered stone, all the insoluble organic materials (IOM) of the meteorites analyzed released significant amounts of ammonia, which varied from over 4 {mu}g mg{sup -1} for the Orgueil IOM to 0.5 {mu}g mg{sup -1} for that of Tagish Lake; the IOM of the pristine Antarctica find GRA95229 remains the most rich in freeable ammonia with 10 {mu}g mg{sup -1}. While the amounts of IOM bound ammonia do not appear to vary between meteorites with a recognizable trend, a possible consequence of long terrestrial exposure of some of the stones, we found that the {delta}{sup 15}N composition of the ammonia-carrying materials is clearly distinctive of meteorite types and may reflect a preservation of the original {sup 15}N distribution of pre- and proto-solar materials.

Wastewater Treatment with Ammonia Recovery System

OpenAIRE

M. Örvös; T. Balázs; K. F. Both

2008-01-01

From environmental aspect purification of ammonia containing wastewater is expected. High efficiency ammonia desorption can be done from the water by air on proper temperature. After the desorption process, ammonia can be recovered and used in another technology. The calculation method described below give some methods to find either the minimum column height or ammonia rich solution of the effluent.

Safety assessment of ammonia as a transport fuel

Energy Technology Data Exchange (ETDEWEB)

Duijm, N.J.; Markert, F.; Lundtang paulsen, Jette

2005-02-01

This report describes the safety study performed as part of the EU supported project 'Ammonia Cracking for Clean Electric Power Technology' The study addresses the following activities: safety of operation of the ammonia-powered vehicle under normal and accident (collision) conditions, safety of transport of ammonia to the refuelling stations and safety of the activities at the refuelling station (unloading and refuelling). Comparisons are made between the safety of using ammonia and the safety of other existing or alternative fuels. The conclusion is that the hazards in relation to ammonia need to be controlled by a combination of technical and regulatory measures. The most important requirements are: - Advanced safety systems in the vehicle - Additional technical measures and regulations are required to avoid releases in maintenance workshops and unauthorised maintenance on the fuel system - Road transport of ammonia to refuelling stations in refrigerated form - Sufficient safety zones between refuelling stations and residential or otherwise public areas. When these measures are applied, the use of ammonia as a transport fuel wouldnt cause more risks than currently used fuels (using current practice). (au)

The Ability of the FTC Method to Quantify Nicotine as a Function of Ammonia in Mainstream Smoke

Directory of Open Access Journals (Sweden)

Callicutt CH

2014-12-01

Full Text Available Whether ammonia-forming ingredients added to tobacco and ammonia in smoke affect the ability of the Cambridge filter pad to trap nicotine in the Federal Trade Commission (FTC method was examined. Three commercial cigarettes, two industry reference cigarettes, and four specially designed test cigarettes were used in this study to represent cigarettes with different construction and mainstream (MS smoke yield characteristics. One of the commercial cigarettes, a US 1998 Marlboro Lights¯ King Size cigarette, was used as a control cigarette for the four experimental test cigarettes. The test cigarettes differed from the control cigarette as follows: first, a reduction in ammonia-forming ingredients added to the reconstituted tobaccos; second, no ammonia-forming ingredients added to the reconstituted tobacco; third, no ingredients at all added to the reconstituted tobaccos; and fourth, no ingredients at all added to the entire tobacco blend. An XAD-4 tube was placed downstream of the standard Cambridge filter pad in the FTC method to trap the gas-vapor phase nicotine for subsequent analysis. The Cambridge filter pad used in the FTC method was determined to provide greater than 99% trapping efficiency for MS smoke nicotine from cigarettes with widely different soluble ammonia levels in filler and MS smoke ammonia yields.

A method for the determination of volatile ammonia in air, using a nitrogen-cooled trap and fluorometric detection

NARCIS (Netherlands)

Westra, H.G.; Tigchelaar, R.G.; Berden, J.A.

2001-01-01

A quick, cheap, and accurate method for the determination of ammonia in air is described. Ammonia and water vapor are trapped simultaneously in a gas sampling tube cooled in liquid nitrogen. Subsequently ammonia is derivatized with o-phthaldialdehyde and determined using fluorescence detection. The

Procedure for the in vitro determination of ammonia in blood

International Nuclear Information System (INIS)

Jung, K.; Faust, H.

1985-01-01

The invention has been aimed at a procedure for the in vitro determination of ammonia in blood based on microdiffusion and isotope dilution analysis. A definite quantity of blood serum has been mixed with a definite quantity of ammonium chloride labelled with the stable isotope 15 N. The mixture has been subjected to the microdiffusion (K 2 CO 3 additives and absorption of released ammonia in sulphuric acid). The ammonia bound in sulphuric acid has been devoted to a isotope analysis and the ammonia concentration of blood has been determined according to the isotope dilution analysis equation

Catalyst for Ammonia Oxidation

DEFF Research Database (Denmark)

2015-01-01

The present invention relates to a bimetallic catalyst for ammonia oxidation, a method for producing a bimetallic catalyst for ammonia oxidation and a method for tuning the catalytic activity of a transition metal. By depositing an overlayer of less catalytic active metal onto a more catalytic...

Ammonia modifies enteric neuromuscular transmission through glial γ-aminobutyric acid signaling.

Science.gov (United States)

Fried, David E; Watson, Ralph E; Robson, Simon C; Gulbransen, Brian D

2017-12-01

Impaired gut motility may contribute, at least in part, to the development of systemic hyperammonemia and systemic neurological disorders in inherited metabolic disorders, or in severe liver and renal disease. It is not known whether enteric neurotransmission regulates intestinal luminal and hence systemic ammonia levels by induced changes in motility. Here, we propose and test the hypothesis that ammonia acts through specific enteric circuits to influence gut motility. We tested our hypothesis by recording the effects of ammonia on neuromuscular transmission in tissue samples from mice, pigs, and humans and investigated specific mechanisms using novel mutant mice, selective drugs, cellular imaging, and enzyme-linked immunosorbent assays. Exogenous ammonia increased neurogenic contractions and decreased neurogenic relaxations in segments of mouse, pig, and human intestine. Enteric glial cells responded to ammonia with intracellular Ca 2+ responses. Inhibition of glutamine synthetase and the deletion of glial connexin-43 channels in hGFAP :: Cre ER T2+/- /connexin43 f/f mice potentiated the effects of ammonia on neuromuscular transmission. The effects of ammonia on neuromuscular transmission were blocked by GABA A receptor antagonists, and ammonia drove substantive GABA release as did the selective pharmacological activation of enteric glia in GFAP::hM3Dq transgenic mice. We propose a novel mechanism whereby local ammonia is operational through GABAergic glial signaling to influence enteric neuromuscular circuits that regulate intestinal motility. Therapeutic manipulation of these mechanisms may benefit a number of neurological, hepatic, and renal disorders manifesting hyperammonemia. NEW & NOTEWORTHY We propose that local circuits in the enteric nervous system sense and regulate intestinal ammonia. We show that ammonia modifies enteric neuromuscular transmission to increase motility in human, pig, and mouse intestine model systems. The mechanisms underlying the

Is there in vivo evidence for amino acid shuttles carrying ammonia from neurons to astrocytes?

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Rothman, Douglas L; De Feyter, Henk M; Maciejewski, Paul K; Behar, Kevin L

2012-11-01

The high in vivo flux of the glutamate/glutamine cycle puts a strong demand on the return of ammonia released by phosphate activated glutaminase from the neurons to the astrocytes in order to maintain nitrogen balance. In this paper we review several amino acid shuttles that have been proposed for balancing the nitrogen flows between neurons and astrocytes in the glutamate/glutamine cycle. All of these cycles depend on the directionality of glutamate dehydrogenase, catalyzing reductive glutamate synthesis (forward reaction) in the neuron in order to capture the ammonia released by phosphate activated glutaminase, while catalyzing oxidative deamination of glutamate (reverse reaction) in the astrocytes to release ammonia for glutamine synthesis. Reanalysis of results from in vivo experiments using (13)N and (15)N labeled ammonia and (15)N leucine in rats suggests that the maximum flux of the alanine/lactate or branched chain amino acid/branched chain amino acid transaminase shuttles between neurons and astrocytes are approximately 3-5 times lower than would be required to account for the ammonia transfer from neurons to astrocytes needed for glutamine synthesis (amide nitrogen) to sustain the glutamate/glutamine cycle. However, in the rat brain both the total ammonia fixation rate by glutamate dehydrogenase and the total branched chain amino acid transaminase activity are sufficient to support a branched chain amino acid/branched chain keto acid shuttle, as proposed by Hutson and coworkers, which would support the de novo synthesis of glutamine in the astrocyte to replace the ~20 % of neurotransmitter glutamate that is oxidized. A higher fraction of the nitrogen needs of total glutamate neurotransmitter cycling could be supported by hybrid cycles in which glutamate and tricarboxylic acid cycle intermediates act as a nitrogen shuttle. A limitation of all in vivo studies in animals conducted to date is that none have shown transfer of nitrogen for glutamine amide

Synthesis of ammonia using sodium melt.

Science.gov (United States)

Kawamura, Fumio; Taniguchi, Takashi

2017-09-14

Research into inexpensive ammonia synthesis has increased recently because ammonia can be used as a hydrogen carrier or as a next generation fuel which does not emit CO 2 . Furthermore, improving the efficiency of ammonia synthesis is necessary, because current synthesis methods emit significant amounts of CO 2 . To achieve these goals, catalysts that can effectively reduce the synthesis temperature and pressure, relative to those required in the Haber-Bosch process, are required. Although several catalysts and novel ammonia synthesis methods have been developed previously, expensive materials or low conversion efficiency have prevented the displacement of the Haber-Bosch process. Herein, we present novel ammonia synthesis route using a Na-melt as a catalyst. Using this route, ammonia can be synthesized using a simple process in which H 2 -N 2 mixed gas passes through the Na-melt at 500-590 °C under atmospheric pressure. Nitrogen molecules dissociated by reaction with sodium then react with hydrogen, resulting in the formation of ammonia. Because of the high catalytic efficiency and low-cost of this molten-Na catalyst, it provides new opportunities for the inexpensive synthesis of ammonia and the utilization of ammonia as an energy carrier and next generation fuel.

Enrichment of ammonia concentration from aqua-ammonia vapors by using 3A molecular sieve

International Nuclear Information System (INIS)

Chiou, J.S.; Lin, T.M.; She, K.Y.; Chen, W.M.

2009-01-01

In aqua-ammonia refrigeration systems, the ammonia is the refrigerant and the water is the absorbent, the vapor produced in the generator always contains a small fraction of water. The removed of this residual water is a crucial issue in order to guarantee a reliable and efficient operation of these systems. Currently, the thermal distillation methods (via a rectifier and/or an analyzer) are used to further separate the water from aqua-ammonia mixtures. In this study, a molecular sieve module is used for ammonia purification. A thermal system with a 3A molecular sieve module was set up, and the conditions of working fluid entering into the sieve module is similar to that entering into the rectifier tower of a typical aqua-ammonia absorption system. Results from ammonia enrichment tests indicate the concentration of ammonia can be raised from about 80% up to about 99% if siever installation was properly arranged.

Sizing of an Ammonia Discharge Tank

Directory of Open Access Journals (Sweden)

Tuliagenda Beckfords

2011-01-01

Full Text Available Phosphate companies use well-stirred tanks to regulate the concentration of ammonia they discharge via their wastewater, preventing ammonia spikes from exceeding the cap set by the Environmental Protection Agency. This report discusses the methods used to determine the minimum possible volume of the tank required to regulate wastewater discharge. With this information, it was determined that the use of a stirring tank is an efficient and cost effective way to regulate ammonia discharge. Based on these results many other companies may use this method to decrease the negative effects of ammonia on the environment.

Preparation of Sm3H7 nanoparticles and their application in ammonia synthesis

International Nuclear Information System (INIS)

Liu Tong; Zhang Yaohua; Li Xingguo

2006-01-01

Sm 3 H 7 nanoparticles have been successfully produced by hydrogen plasma-metal reaction (HPMR) method, and then used to synthesize ammonia at 298 K and 1 atm. The morphologies of the Sm 3 H 7 nanoparticles before and after reaction were investigated by transmission electron microscopy, and the crystal structures at different steps by X-ray diffraction. Nessler's test was adopted to detect ammonia. It was found that the passivated Sm 3 H 7 nanoparticles possess polyhedron shape and smooth surface, with the average size of about 50 nm and the specific surface area 11.2 m 2 g -1 . It was proposed that Sm 3 H 7 nanoparticles react with oxygen and nitrogen to form ammonia, but ammonia production is not observable in the case of coarse particles. After ammonia synthesis, the morphology of Sm 3 H 7 nanoparticles changes into spongy surface and the mean particle size and specific surface area increase to 100 nm and 28.6 m 2 g -1 , respectively, due to the release of hydrogen. The hydrogen conversion percentage from samarium hydride is estimated to be 1.5%. Without O 2 , Sm 3 H 7 nanoparticles cannot react with N 2 or N 2 + H 2 at 298 K and 1 atm

Accelerated in-vitro release testing methods for extended-release parenteral dosage forms.

Science.gov (United States)

Shen, Jie; Burgess, Diane J

2012-07-01

This review highlights current methods and strategies for accelerated in-vitro drug release testing of extended-release parenteral dosage forms such as polymeric microparticulate systems, lipid microparticulate systems, in-situ depot-forming systems and implants. Extended-release parenteral dosage forms are typically designed to maintain the effective drug concentration over periods of weeks, months or even years. Consequently, 'real-time' in-vitro release tests for these dosage forms are often run over a long time period. Accelerated in-vitro release methods can provide rapid evaluation and therefore are desirable for quality control purposes. To this end, different accelerated in-vitro release methods using United States Pharmacopeia (USP) apparatus have been developed. Different mechanisms of accelerating drug release from extended-release parenteral dosage forms, along with the accelerated in-vitro release testing methods currently employed are discussed. Accelerated in-vitro release testing methods with good discriminatory ability are critical for quality control of extended-release parenteral products. Methods that can be used in the development of in-vitro-in-vivo correlation (IVIVC) are desirable; however, for complex parenteral products this may not always be achievable. © 2012 The Authors. JPP © 2012 Royal Pharmaceutical Society.

Accelerated in vitro release testing methods for extended release parenteral dosage forms

Science.gov (United States)

Shen, Jie; Burgess, Diane J.

2012-01-01

Objectives This review highlights current methods and strategies for accelerated in vitro drug release testing of extended release parenteral dosage forms such as polymeric microparticulate systems, lipid microparticulate systems, in situ depot-forming systems, and implants. Key findings Extended release parenteral dosage forms are typically designed to maintain the effective drug concentration over periods of weeks, months or even years. Consequently, “real-time” in vitro release tests for these dosage forms are often run over a long time period. Accelerated in vitro release methods can provide rapid evaluation and therefore are desirable for quality control purposes. To this end, different accelerated in vitro release methods using United States Pharmacopoeia (USP) apparatus have been developed. Different mechanisms of accelerating drug release from extended release parenteral dosage forms, along with the accelerated in vitro release testing methods currently employed are discussed. Conclusions Accelerated in vitro release testing methods with good discriminatory ability are critical for quality control of extended release parenteral products. Methods that can be used in the development of in vitro-in vivo correlation (IVIVC) are desirable, however for complex parenteral products this may not always be achievable. PMID:22686344

Optimization of an auto-thermal ammonia synthesis reactor using cyclic coordinate method

Science.gov (United States)

A-N Nguyen, T.; Nguyen, T.-A.; Vu, T.-D.; Nguyen, K.-T.; K-T Dao, T.; P-H Huynh, K.

2017-06-01

The ammonia synthesis system is an important chemical process used in the manufacture of fertilizers, chemicals, explosives, fibers, plastics, refrigeration. In the literature, many works approaching the modeling, simulation and optimization of an auto-thermal ammonia synthesis reactor can be found. However, they just focus on the optimization of the reactor length while keeping the others parameters constant. In this study, the other parameters are also considered in the optimization problem such as the temperature of feed gas enters the catalyst zone, the initial nitrogen proportion. The optimal problem requires the maximization of an objective function which is multivariable function and subject to a number of equality constraints involving the solution of coupled differential equations and also inequality constraint. The cyclic coordinate search was applied to solve the multivariable-optimization problem. In each coordinate, the golden section method was applied to find the maximum value. The inequality constraints were treated using penalty method. The coupled differential equations system was solved using Runge-Kutta 4th order method. The results obtained from this study are also compared to the results from the literature.

Environmental burden by nitrogen from agriculture in the Netherlands. Outline of effects of manure and ammonia measures

International Nuclear Information System (INIS)

Kros, J.; De Vries, W.; Oenema, O.

2004-01-01

The nitrogen emission ceiling has been introduced to be able to assess the effectiveness of measures to control manure and ammonia. This integral method shows the effects of several policy options on the release of nitrogen from the agricultural sector into the environment on a regional scale [nl

Exergy analysis of industrial ammonia synthesis

International Nuclear Information System (INIS)

Kirova-Yordanova, Zornitza

2004-01-01

Exergy consumption of ammonia production plants depends strongly on the ammonia synthesis loop design. Due to the thermodynamically limited low degree of conversion of hydrogen-nitrogen mixture to ammonia, industrial ammonia synthesis is implemented as recycle process (so-called 'ammonia synthesis loop'). Significant quantities of reactants are recycled back to reactor, after the removal of ammonia at low temperatures. Modern ammonia synthesis plants use well-developed heat- and cold recovery to improve the reaction heat utilisation and to reduce the refrigeration costs. In this work, the exergy method is applied to estimate the effect of the most important process parameters on the exergy efficiency of industrial ammonia synthesis. A specific approach, including suitable definitions of the system boundaries and process parameters, is proposed. Exergy efficiency indexes are discussed in order to make the results applicable to ammonia synthesis loops of various designs. The dependence of the exergy losses on properly selected independent process parameters is studied. Some results from detailed exergy analysis of the most commonly used ammonia synthesis loop design configurations at a wide range of selected parameters values are shown

Pretreatment of Biomass by Aqueous Ammonia for Bioethanol Production

Science.gov (United States)

Kim, Tae Hyun; Gupta, Rajesh; Lee, Y. Y.

The methods of pretreatment of lignocellulosic biomass using aqueous ammonia are described. The main effect of ammonia treatment of biomass is delignification without significantly affecting the carbohydrate contents. It is a very effective pretreatment method especially for substrates that have low lignin contents such as agricultural residues and herbaceous feedstock. The ammonia-based pretreatment is well suited for simultaneous saccharification and co-fermentation (SSCF) because the treated biomass retains cellulose as well as hemicellulose. It has been demonstrated that overall ethanol yield above 75% of the theoretical maximum on the basis of total carbohydrate is achievable from corn stover pretreated with aqueous ammonia by way of SSCF. There are two different types of pretreatment methods based on aqueous ammonia: (1) high severity, low contact time process (ammonia recycle percolation; ARP), (2) low severity, high treatment time process (soaking in aqueous ammonia; SAA). Both of these methods are described and discussed for their features and effectiveness.

New method for the temperature-programmed desorption (TPD) of ammonia experiment for characterization of zeolite acidity: a review.

Science.gov (United States)

Niwa, Miki; Katada, Naonobu

2013-10-01

In this review, a method for the temperature-programmed desorption (TPD) of ammonia experiment for the characterization of zeolite acidity and its improvement by simultaneous IR measurement and DFT calculation are described. First, various methods of ammonia TPD are explained, since the measurements have been conducted under the concepts of kinetics, equilibrium, or diffusion control. It is however emphasized that the ubiquitous TPD experiment is governed by the equilibrium between ammonia molecules in the gas phase and on the surface. Therefore, a method to measure quantitatively the strength of the acid site (∆H upon ammonia desorption) under equilibrium-controlled conditions is elucidated. Then, a quantitative relationship between ∆H and H0 function is proposed, based on which the acid strength ∆H can be converted into the H0 function. The identification of the desorption peaks and the quantitative measurement of the number of acid sites are then explained. In order to overcome a serious disadvantage of the method (i.e., no information is provided about the structure of acid sites), the simultaneous measurement of IR spectroscopy with ammonia TPD, named IRMS-TPD (infrared spectroscopy/mass spectrometry-temperature-programmed desorption), is proposed. Based on this improved measurement, Brønsted and Lewis acid sites were differentiated and the distribution of Brønsted OH was revealed. The acidity characterized by IRMS-TPD was further supported by the theoretical DFT calculation. Thus, the advanced study of zeolite acidity at the molecular level was made possible. Advantages and disadvantages of the ammonia TPD experiment are discussed, and understanding of the catalytic cracking activity based on the derived acidic profile is explained. Copyright © 2013 The Chemical Society of Japan and Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Numerical Study of Ammonia Leak and Dispersion in the International Space Station

Science.gov (United States)

Son, Chang H.

2012-01-01

Release of ammonia into the International Space Station (ISS) cabin atmosphere can occur if the water/ammonia barrier breach of the active thermal control system (ATCS) interface heat exchanger (IFHX) happens. After IFHX breach liquid ammonia is introduced into the water-filled internal thermal control system (ITCS) and then to the cabin environment through a ruptured gas trap. Once the liquid water/ammonia mixture exits ITCS, it instantly vaporizes and mixes with the U.S. Laboratory cabin air that results in rapid deterioration of the cabin conditions. The goal of the study is to assess ammonia propagation in the Station after IFHX breach to plan the operation procedure. A Computational Fluid Dynamics (CFD) model for accurate prediction of airflow and ammonia transport within each of the modules in the ISS cabin was developed. CFD data on ammonia content in the cabin aisle way of the ISS and, in particular, in the Russian On- Orbit Segment during the period of 15 minutes after gas trap rupture are presented for four scenarios of rupture response. Localized effects of ammonia dispersion and risk mitigation are discussed.

A process to remove ammonia from PUREX plant effluents

International Nuclear Information System (INIS)

Moore, J.D.

1990-01-01

Zirconium-clad nuclear fuel from the Hanford N-Reactor is reprocessed in the PUREX (Plutonium Uranium Extraction) Plant operated by the Westinghouse Hanford Comapny. Before dissolution, cladding is chemically removed from the fuel elements with a solution of ammonium fluoride-ammonium nitrate (AFAN). a solution batch with an ammonia equivalent of about 1,100 kg is added to each fuel batch of 10 metric tons. This paper reports on this decladding process, know as the 'Zirflex' process which produces waste streams containing ammonia and ammonium slats. Waste stream treatment, includes ammonia scrubbing, scrub solution evaporation, residual solids dissolution, and chemical neutralization. These processes produce secondary liquid and gaseous waste streams containing varying concentrations of ammonia and low-level concentrations of radionuclides. Until legislative restrictions were imposed in 1987, these secondary streams were released to the soil in a liquid disposal 'crib' and to the atmosphere

Footprints on Ammonia Concentrations from Environmental Regulations

DEFF Research Database (Denmark)

Skjøth, Carsten Ambelas; Ellermann, Thomas; Hertel, Ole

2008-01-01

Releases of ammonia (NH3) to the atmosphere contribute significantly to the desposition of nitrogen to both terrestrial and aquatic ecosystems. This is the background for the national NH3 emission ceilings in Europe. However, in some countries the national legislation aims not only to meet theese...

USE OF ZEOLITE FOR REMOVING AMMONIA AND AMMONIA-CAUSED TOXCITY IN MARINE TOXICITY IDENTIFCATION EVALUATIONS (TIES)

Science.gov (United States)

Ammonia occurs in marine waters including effluents, receiving waters, and sediment interstitial waters. At sufficiently high concentrations, ammonia can be toxic to aquatic species. Toxicity identification evaluation (TIE) methods provide researchers with tools for identifyi...

Ammonia Generation via a Graphene-Coated Nickel Catalyst

Directory of Open Access Journals (Sweden)

Fei Lu

2017-05-01

Full Text Available A novel graphene-coated Ni electrode was developed in this investigation to improve corrosion resistance while unexpectedly enhancing the ammonia generation rate in the electrochemically induced urea to ammonia (eU2A process, which is an electrochemical onsite ammonia generation method. The development of the electrode is crucial for the eU2A reactions since in the ammonia generation process, the concentration of ammonia is inevitably high on the surface of the electrode, leading to severe corrosion of the electrode and the loss of generated ammonia as well. In this paper, the graphene was derived from raw coal by using the chemical vapor deposition method and self-lifted onto a Ni electrode to form a protective layer for corrosion prevention. Transmission electron microscopy showed the synthesized graphene had few-layers and Raman spectroscopy indicated that the coating of graphene was stable during the eU2A reaction. As a result, the ammonia corrosion of the Ni electrode was dramatically reduced by ~20 times with the graphene coating method. More importantly, a higher ammonia generation rate (~2 times was achieved using the graphene-coated Ni working electrode compared to a bare Ni electrode in the eU2A process.

Final Report for the DOE-BES Program Mechanistic Studies of Activated Hydrogen Release from Amine-Boranes

Energy Technology Data Exchange (ETDEWEB)

Larry G. Sneddon; R. Thomas Baker

2013-01-13

Effective storage of hydrogen presents one of the most significant technical gaps to successful implementation of the hydrogen economy, particularly for transportation applications. Amine boranes, such as ammonia borane H3NBH3 and ammonia triborane H3NB3H7, have been identified as promising, high-capacity chemical hydrogen storage media containing potentially readily released protic (N-H) and hydridic (B-H) hydrogens. At the outset of our studies, dehydrogenation of ammonia borane had been studied primarily in the solid state, but our DOE sponsored work clearly demonstrated that ionic liquids, base-initiators and/or metal-catalysts can each significantly increase both the rate and extent of hydrogen release from amine boranes under moderate conditions. Our studies also showed that depending upon the activation method, hydrogen release from amine boranes can occur by very different mechanistic steps and yield different types of spent-fuel materials. The fundamental understanding that was developed during this grant of the pathways and controlling factors for each of these hydrogen-release mechanisms is now enabling continuing discovery and optimization of new chemical-hydride based hydrogen storage systems.

Ammonia and carbon dioxide emissions by stabilized conventional nitrogen fertilizers and controlled release in corn crop

Directory of Open Access Journals (Sweden)

Taylor Lima de Souza

Full Text Available ABSTRACT The market of stabilized, slow and controlled release nitrogen (N fertilizers represents 1% of the world fertilizer consumption. On the other hand, the increase in availability, innovation and application of these technologies could lead to the improvement of N use efficiency in agroecossystems and to the reduction of environmental impacts. The objective of this study was to quantify agronomic efficiency relative index, ammonia volatilization, and CO2 emissions from conventional, stabilized and controlled release N fertilizers in corn summer crop. The experiment was carried out in a corn crop area located in Lavras, state of Minas Gerais, Brazil, without irrigation. All treatments were applied in topdressing at rate of 150 kg ha-1 N. N-NH3 losses from N fertilizers were: Granular urea (39% of the applied N = prilled urea (38% > urea coated with 16% S0 (32% = blend of urea + 7.9% S0 + polymers + conventional urea (32% > prilled urea incorporated at 0.02 m depth (24% > urea + 530 mg kg-1 of NBPT (8% = Hydrolyzed leather (9% > urea + thermoplastic resin (3% = ammonium sulfate (1% = ammonium nitrate (0.7%. Thermoplastic resin coated urea, ammonium nitrate and ammonium sulfate presented low values of cumulative CO2 emissions in corn crop. On the other hand, hydrolyzed leather promoted greater C-CO2 emission, when compared with other nitrogen fertilizers.

Evaluation of ammonia metabolism in the skeletal muscles of patients with cirrhosis using N-13 ammonia PET

International Nuclear Information System (INIS)

Susumu Shiomi; Etsushi Kawamura; Takehiro Hayashi; Ai Oe; Jin Kotani; Hirotaka Ishizu; Kenji Torii; Joji Kawabe; Akihiro Tamori; Daiki Habu; Tadashi Takeda; Shuhei Nishiguchi

2004-01-01

Purpose: Hepatic encephalopathy is one of the causes of death of patients with liver cirrhosis, and treatment of this encephalopathy is important for patients with liver cirrhosis. Ammonia plays a major role in the pathogenesis of hepatic encephalopathy. Ammonia is mainly generated in vivo by deamination of amino acids in proteins ingested as food, but some is produced by intestinal bacteria. The generated ammonia reaches the liver through the portal vein, is converted to urea by means of the urea cycle and excreted from the kidney. In patients with decreased hepatic functional reserve or those with porto-systemic shunt, ammonia level in the blood rises. The excessive ammonia in such cases is mainly metabolized in skeletal muscles, However, skeletal muscles have no urea cycle, and therefore metabolize ammonia by producing glutamine from glutamate. Branched-chain amino acids (BCAA) is required for this reaction. Ammonia is considered the major pathogenetic factor of hepatic encephalopathy. It has been reported in animal experiments that skeletal muscles compensate for the decreased ammonia metabolism in cirrhotic liver. Positron emission tomography (PET) with N-13 ammonia has been widely used for the evaluation of myocardial perfusion. We examined ammonia metabolism in the skeletal muscles in patients with liver cirrhosis before and after administration of BCAA using N-13 ammonia PET.. Methods: The subjects were patients with cirrhosis underlying hepatitis C virus infection. Case 1 was a 68-year-old man diagnosed with compensated liver cirrhosis. Both ascites and encephalopathy were absent. The red blood cell count was 365 X 10 4 /ml, the platelet count was 14.6 serum albumin concentration was 4.2 g/dl, the cholinesterase activity was 396 IU/l, the total bi concentration was 0.6 mg/dl, the blood ammonia was 52 g/dl, the prothrombin time was 150%, and branched-chain amino acid and tyrosin ratio (BTR) was 6.60. Case 2 was a 69-year-old woman diagnosed with

Ammonia blood test

Science.gov (United States)

... page: //medlineplus.gov/ency/article/003506.htm Ammonia blood test To use the sharing features on this page, ... Encephalopathy - ammonia; Cirrhosis - ammonia; Liver failure - ammonia Images Blood test References Chernecky CC, Berger BJ. Ammonia (NH3) - blood ...

Synthesis of ammonia using sodium melt

OpenAIRE

Kawamura, Fumio; Taniguchi, Takashi

2017-01-01

Research into inexpensive ammonia synthesis has increased recently because ammonia can be used as a hydrogen carrier or as a next generation fuel which does not emit CO2. Furthermore, improving the efficiency of ammonia synthesis is necessary, because current synthesis methods emit significant amounts of CO2. To achieve these goals, catalysts that can effectively reduce the synthesis temperature and pressure, relative to those required in the Haber-Bosch process, are required. Although severa...

Effects of diurnal emission patterns and sampling frequency on precision of measurement methods for daily ammonia emissions from animal houses

NARCIS (Netherlands)

Estelles, F.; Calvet, S.; Ogink, N.W.M.

2010-01-01

Ammonia concentrations and airflow rates are the main parameters needed to determine ammonia emissions from animal houses. It is possible to classify their measurement methods into two main groups according to the sampling frequency: semi-continuous and daily average measurements. In the first

Advances in Support of the CMAQ Bidirectional Science Option for the Estimation of Ammonia Flux from Agricultural cropland

Science.gov (United States)

Proposed Session: Emissions Inventories, Models and processes: Last year a new CMAQ bidirectional option for the estimation of ammonia flux (emission and deposition) was released. This option essentially replaces NEI crop ammonia emissions with emissions calculated dynamically...

Fate of Ammonia in the Atmosphere - A Review for Applicability to Hazardous Releases

National Research Council Canada - National Science Library

Renard, Jean

2004-01-01

.... Capture by atmospheric moisture (clouds, rain, fog), surface waters (rivers, lakes, seas), and deposition on vegetation and soil constitute the main pathways for ammonia removal from the troposphere...

Regeneration of ammonia borane from polyborazylene

Science.gov (United States)

Sutton, Andrew; Gordon, John C; Ott, Kevin C; Burrell, Anthony K

2013-02-05

Method of producing ammonia borane, comprising providing a reagent comprising a dehydrogenated material in a suitable solvent; and combining the reagent with a reducing agent comprising hydrazine, a hydrazine derivative, or combinations thereof, in a reaction which produces a mixture comprising ammonia borane.

Ammonia intoxication

International Nuclear Information System (INIS)

Bessman, S.P.; Pal, N.

1982-01-01

Data is presented which shows that there is a relation between ammonia concentration in the blood and state of consciousness. The concentrations of GTP and ATP also relate both to the ammonia concentration in blood and the state of consciousness. The rate of protein synthesis in the brain as measured by the percent of intracellular counts that are incorporated into protein is also related to ammonia concentration. These findings of energy depletion and depressed synthesis resulting from energy depletion suggest that the primary lesion in ammonia intoxication involves the Krebs cycle. The greater effect of ammonia on GTP than on ATP metabolism supports the view that the primary site of action of ammonia is at the glutamate dehydrogenase-ketoglutarate reduction step - and is consistent with previous work on this subject. (H.K.)

Impact Assessment and Environmental Evaluation of Various Ammonia Production Processes

Science.gov (United States)

Bicer, Yusuf; Dincer, Ibrahim; Vezina, Greg; Raso, Frank

2017-05-01

In the current study, conventional resources-based ammonia generation routes are comparatively studied through a comprehensive life cycle assessment. The selected ammonia generation options range from mostly used steam methane reforming to partial oxidation of heavy oil. The chosen ammonia synthesis process is the most common commercially available Haber-Bosch process. The essential energy input for the methods are used from various conventional resources such as coal, nuclear, natural gas and heavy oil. Using the life cycle assessment methodology, the environmental impacts of selected methods are identified and quantified from cradle to gate. The life cycle assessment outcomes of the conventional resources based ammonia production routes show that nuclear electrolysis-based ammonia generation method yields the lowest global warming and climate change impacts while the coal-based electrolysis options bring higher environmental problems. The calculated greenhouse gas emission from nuclear-based electrolysis is 0.48 kg CO2 equivalent while it is 13.6 kg CO2 per kg of ammonia for coal-based electrolysis method.

Ethylene and ammonia traces measurements from the patients' breath with renal failure via LPAS method

Science.gov (United States)

Popa, C.; Dutu, D. C. A.; Cernat, R.; Matei, C.; Bratu, A. M.; Banita, S.; Dumitras, D. C.

2011-11-01

The application of laser photoacoustic spectroscopy (LPAS) for fast and precise measurements of breath biomarkers has opened up new promises for monitoring and diagnostics in recent years, especially because breath test is a non-invasive method, safe, rapid and acceptable to patients. Our study involved assessment of breath ethylene and breath ammonia levels in patients with renal failure receiving haemodialysis (HD) treatment. Breath samples from healthy subjects and from patients with renal failure were collected using chemically inert aluminized bags and were subsequently analyzed using the LPAS technique. We have found out that the composition of exhaled breath in patients with renal failure contains not only ethylene, but also ammonia and gives valuable information for determining efficacy and endpoint of HD. Analysis of ethylene and ammonia traces from the human breath may provide insight into severity of oxidative stress and metabolic disturbances and may ensure optimal therapy and prevention of pathology at patients on continuous HD.

The re-assimilation of ammonia produced by photorespiration and the nitrogen economy of C3 higher plants.

Science.gov (United States)

Keys, Alfred J

2006-02-01

Photorespiration involves the conversion of glycine to serine with the release of ammonia and CO(2). In C(3) terrestrial higher plants the flux through glycine and serine is so large that it results in the production of ammonia at a rate far exceeding that from reduction of new nitrogen entering the plant. The photorespiratory nitrogen cycle re-assimilates this ammonia using the enzymes glutamine synthetase and glutamine:2-oxoglutarateaminotransferase.

Effects of end-stage renal disease and dialysis modalities on blood ammonia level.

Science.gov (United States)

Vaziri, Nosratola D; Khazaeli, Mahyar; Nunes, Ane C F; Harley, Kevin T; Said, Hyder; Alipour, Omeed; Lau, Wei Ling; Pahl, Madeleine V

2017-07-01

Uremia results in a characteristic breath odor (uremic fetor) which is largely due to its high ammonia content. Earlier studies have shown a strong correlation between breath ammonia and blood urea levels and a 10-fold reduction in breath ammonia after hemodialysis in patients with chronic kidney disease. Potential sources of breath ammonia include: (i) local ammonia production from hydrolysis of urea in the oropharyngeal and respiratory tracts by bacterial flora, and (ii) release of circulating blood ammonia by the lungs. While the effects of uremia and hemodialysis on breath ammonia are well known their effects on blood ammonia are unknown and were explored here. Blood samples were obtained from 23 hemodialysis patients (immediately before and after dialysis), 14 peritoneal dialysis patients, and 10 healthy controls. Blood levels of ammonia, creatinine, urea, and electrolytes were measured. No significant difference was found in baseline blood ammonia between hemodialysis, peritoneal dialysis and control groups. Hemodialysis procedure led to a significant reduction in urea concentration (P ammonia level in 10 of the 23 patients studied. Change in blood ammonia pre- and post-hemodialysis correlated with change in serum bicarbonate levels (r = 0.61, P ammonia levels after dialysis, there was a strong correlation with drop in mean arterial pressure (r = 0.88, P ammonia compared to the patients who manifested a fall in blood ammonia (124 ± 8 vs. 136 ± 6 mmHg respectively, P = 0.27). Fall in blood urea following hemodialysis in ESRD patients was paradoxically accompanied by a modest rise in blood ammonia levels in 43% of the patients studied, contrasting prior reported effects of hemodialysis on breath ammonia. In this subgroup of patients, changes in blood ammonia during hemodialysis correlated with rise in blood bicarbonate and fall in mean arterial blood pressure. © 2016 International Society for Hemodialysis.

IRIS Toxicological Review of Ammonia (Revised External Review Draft)

Science.gov (United States)

In August 2013, EPA submitted a revised draft IRIS assessment of ammonia to the agency's Science Advisory Board (SAB) and posted this draft on the IRIS website. EPA had previously released a draft of the assessment for public comment, held a public meeting about the draft, and ...

Investigation into ammonia stress on Cyperus alternifolius and its impact on nutrient removal in microcosm experiments.

Science.gov (United States)

Tao, Wendong; Han, Jianqiu; Li, Hanyan

2015-11-01

Ammonia stress on plants has been investigated at discrete ammonia concentrations in constructed wetlands. This study introduced a Gaussian model to simulate the kinetics of ammonia stress and investigated reversible and irreversible ammonia stress on Cyperus alternifolius in wetland-like microcosms. Ammonia stress on plant weight increase and oxygen release potential started at weekly ammonia concentrations of 27 and 28 mg N/L, reached 50% inhibition at 178 and 158 mg N/L, and resulted in lethal effects at 311 and 303 mg N/L, respectively. The stress of one-time ammonia concentrations up to 400 mg N/L could be reversible. Ammonia concentrations constantly above 219 mg N/L exerted irreversible stress. In the microcosms with ammonia concentrations above the 50% inhibition levels, plants played a minor role in nitrogen removal. Nitrogen removal performance was not affected considerably by ammonia stress. Orthophosphate removal was suppressed by ammonia stress due to less plant uptake. Design and operation of constructed wetlands should consider wastewater ammonia concentration so that the integrity of constructed wetland ecosystems can be maintained. Copyright © 2015 Elsevier Ltd. All rights reserved.

Porous Materials for Hydrolytic Dehydrogenation of Ammonia Borane

Directory of Open Access Journals (Sweden)

Tetsuo Umegaki

2015-07-01

Full Text Available Hydrogen storage is still one of the most significant issues hindering the development of a “hydrogen energy economy”. Ammonia borane is notable for its high hydrogen densities. For the material, one of the main challenges is to release efficiently the maximum amount of the stored hydrogen. Hydrolysis reaction is a promising process by which hydrogen can be easily generated from this compound. High purity hydrogen from this compound can be evolved in the presence of solid acid or metal based catalyst. The reaction performance depends on the morphology and/or structure of these materials. In this review, we survey the research on nanostructured materials, especially porous materials for hydrogen generation from hydrolysis of ammonia borane.

Porous Materials for Hydrolytic Dehydrogenation of Ammonia Borane.

Science.gov (United States)

Umegaki, Tetsuo; Xu, Qiang; Kojima, Yoshiyuki

2015-07-21

Hydrogen storage is still one of the most significant issues hindering the development of a "hydrogen energy economy". Ammonia borane is notable for its high hydrogen densities. For the material, one of the main challenges is to release efficiently the maximum amount of the stored hydrogen. Hydrolysis reaction is a promising process by which hydrogen can be easily generated from this compound. High purity hydrogen from this compound can be evolved in the presence of solid acid or metal based catalyst. The reaction performance depends on the morphology and/or structure of these materials. In this review, we survey the research on nanostructured materials, especially porous materials for hydrogen generation from hydrolysis of ammonia borane.

Ammonia Sensor Using Wavelength Modulation Spectroscopy

KAUST Repository

Farooq, Aamir; Owen, Kyle

2015-01-01

An ammonia sensor can include a laser detector configured to provide stable sample readings. The sensor can implement a method including processing the recorded intensity of the laser beam to determine a first harmonic component and a second harmonic component and the amount of ammonia in the sample.

Ammonia Sensor Using Wavelength Modulation Spectroscopy

KAUST Repository

Farooq, Aamir

2015-09-01

An ammonia sensor can include a laser detector configured to provide stable sample readings. The sensor can implement a method including processing the recorded intensity of the laser beam to determine a first harmonic component and a second harmonic component and the amount of ammonia in the sample.

Techniques for measuring ammonia in fly ash, mortar, and concrete

Energy Technology Data Exchange (ETDEWEB)

Rathbone, R.F. [Kentucky Univ., Lexington, KY (United States). Center for Applied Energy Reseach; Majors, R.K. [Boral Material Technologies, Inc., San Antonio, TX (United States). Engineered Materials

2003-12-01

The presence of ammonia in fly ash that is to be used in mortar and concrete is of increasing concern in the U.S., mainly due to the installation of selective catalytic reduction (SCR) DeNOx systems. When the SCR catalyst is new, contamination of the fly ash with ammonia is generally not a concern. However, as the catalyst in the SCR ages and becomes less efficient, the ammonia slip increases and results in a greater amount of ammonium salt being precipitated on the fly ash. The increase in ammonia concentration is compounded by variability that can occur on a day-to-day basis. When marketing ammonia-laden fly ash for use in mortar and concrete it is imperative that the concentration of ammonia is known. However, there currently is no widely accepted or ''standard'' method for ammonia measurement in fly ash. This paper describes two methods that have been developed and used by the University of Kentucky Center for Applied Energy Research and Boral Material Technologies, Inc. One of the methods uses gas detection tubes and can provide an accurate determination within five to ten minutes. Thus it is suitable as a rapid field technique. The other method employs a gas-sensing electrode and requires a longer period of time to complete the measurement. However, this second method can also be used to determine the quantity of ammonia in fresh mortar and concrete. (orig.)

Impact Assessment and Environmental Evaluation of Various Ammonia Production Processes.

Science.gov (United States)

Bicer, Yusuf; Dincer, Ibrahim; Vezina, Greg; Raso, Frank

2017-05-01

In the current study, conventional resources-based ammonia generation routes are comparatively studied through a comprehensive life cycle assessment. The selected ammonia generation options range from mostly used steam methane reforming to partial oxidation of heavy oil. The chosen ammonia synthesis process is the most common commercially available Haber-Bosch process. The essential energy input for the methods are used from various conventional resources such as coal, nuclear, natural gas and heavy oil. Using the life cycle assessment methodology, the environmental impacts of selected methods are identified and quantified from cradle to gate. The life cycle assessment outcomes of the conventional resources based ammonia production routes show that nuclear electrolysis-based ammonia generation method yields the lowest global warming and climate change impacts while the coal-based electrolysis options bring higher environmental problems. The calculated greenhouse gas emission from nuclear-based electrolysis is 0.48 kg CO 2 equivalent while it is 13.6 kg CO 2 per kg of ammonia for coal-based electrolysis method.

Experimental Setup for Determining Ammonia-Salt Adsorption and Desorption Behavior Under Typical Heat Pump Conditions. Experimental Results

Energy Technology Data Exchange (ETDEWEB)

Van der Pal, M.; De Boer, R.; Veldhuis, J.B.J. [ECN Biomass and Energy Efficiency, Petten (Netherlands)

2013-09-15

For the aim of obtaining a better understanding of the performance of a salt-ammonia sorption reactor/heat exchanger a new test-rig was developed. This test-rig enables the measurement of the performance in adsorption and desorption mode of different sorption reactor designs. It measures the speed of uptake and release of ammonia gas of various salt-ammonia reactions under well-controlled and well-monitored process conditions, similar to the heat pump conditions. The test-rig measures the ammonia uptake and release under controlled pressure and temperature conditions. Temperatures of the salt reactor can be varied from ambient temperature up to 200{sup o}C and the ammonia pressure can be varied between 0.02 to 2 MPa. These conditions can be set independently and repeated at regular time-intervals. Besides NH3-mass-flow meters, pressure and temperature sensors, the setup also contains an endoscope to observe any macroscopic structural changes in the material during uptake and release of ammonia. Measurements so far have shown a liquid phase of LiCl.3NH3 at pressures of 0.5 MPa and temperatures exceeding 90{sup o}C. Voilent foaming is observed at 120{sup o}C resulting in salt losses. A correlation was determined between the reaction rate of MgCl{sub 2}(2-6)NH3 and the relative pressure gradient yielding a reaction time of about 1500 seconds for a relative pressure difference of 1. Multiple sorption cycles of the CaCl{sub 2}(2-4)NH3 reaction, showed a reduced activity from 85% of the theoretical maximum sorbed mass at the first sorption cycle, to 15% after 300+ cycles.

Monitoring the ammonia loading of zeolite-based ammonia SCR catalysts by a microwave method

Energy Technology Data Exchange (ETDEWEB)

Reiss, S.; Schoenauer, D.; Hagen, G.; Moos, R. [University of Bayreuth, Department of Functional Materials, Bayreuth (Germany); Fischerauer, G. [University of Bayreuth, Department of Metrology and Control, Bayreuth (Germany)

2011-05-15

Exhaust gas aftertreatment systems, which reduce nitrogen oxide emissions of heavy-duty diesel engines, commonly use a selective catalytic reduction (SCR) catalyst. Currently, emissions are controlled by evaluating NO{sub x} or NH{sub 3} in the gas phase downstream the catalyst and calculating the NH{sub 3} loading via a chemical storage model. Here, a microwave-cavity perturbation method is proposed in which electromagnetic waves are excited by probe feeds and the reflected signals are measured. At distinct resonance frequencies, the reflection coefficient shows a pronounced minimum. These resonance frequencies depend almost linearly on the NH{sub 3} loading of a zeolite-based SCR catalyst. Since the NH{sub 3} loading-dependent electrical properties of the catalyst material itself are measured, the amount of stored ammonia can be determined directly and in situ. The cross-sensitivity towards water can be reduced almost completely by selecting an appropriate frequency range. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Procedures for the synthesis of ethylenediamine bisborane and ammonia borane

Science.gov (United States)

Ramachandran, Padi Veeraraghavan; Gagare, Pravin D.; Mistry, Hitesh; Biswas, Bidyut

2017-01-03

A method for synthesizing ammonia borane includes (a) preparing a reaction mixture in one or more solvents, the reaction mixture containing sodium borohydride, at least one ammonium salt, and ammonia; and (b) incubating the reaction mixture at temperatures between about 0.degree. C. to about room temperature in an ambient air environment under conditions sufficient to form ammonia borane. Methods for synthesizing ethylenediamine bisborane, and methods for dehydrogenation of ethylenediamine bisborane are also described.

Submersible microbial desalination cell for simultaneous ammonia recovery and electricity production from anaerobic reactors containing high levels of ammonia.

Science.gov (United States)

Zhang, Yifeng; Angelidaki, Irini

2015-02-01

High ammonia concentration in anaerobic reactors can seriously inhibit the anaerobic digestion process. In this study, a submersible microbial desalination cell (SMDC) was developed as an innovative method to lower the ammonia level in a continuous stirred tank reactor (CSTR) by in situ ammonia recovery and electricity production. In batch experiment, the ammonia concentration in the CSTR decreased from 6 to 0.7 g-N/L during 30 days, resulting in an average recovery rate of 80 g-N/m(2)/d. Meanwhile, a maximum power density of 0.71±0.5 W/m(2) was generated at 2.85 A/m(2). Both current driven NH4(+) migration and free NH3 diffusion were identified as the mechanisms responsible for the ammonia transportation. With an increase in initial ammonia concentration and a decrease in external resistance, the SMDC performance was enhanced. In addition, the coexistence of other cations in CSTR or cathode had no negative effect on the ammonia transportation. Copyright © 2014 Elsevier Ltd. All rights reserved.

System and method for determining an ammonia generation rate in a three-way catalyst

Science.gov (United States)

Sun, Min; Perry, Kevin L; Kim, Chang H

2014-12-30

A system according to the principles of the present disclosure includes a rate determination module, a storage level determination module, and an air/fuel ratio control module. The rate determination module determines an ammonia generation rate in a three-way catalyst based on a reaction efficiency and a reactant level. The storage level determination module determines an ammonia storage level in a selective catalytic reduction (SCR) catalyst positioned downstream from the three-way catalyst based on the ammonia generation rate. The air/fuel ratio control module controls an air/fuel ratio of an engine based on the ammonia storage level.

Submersible microbial desalination cell for simultaneous ammonia recovery and electricity production from anaerobic reactors containing high levels of ammonia

DEFF Research Database (Denmark)

Zhang, Yifeng; Angelidaki, Irini

2015-01-01

High ammonia concentration in anaerobic reactors can seriously inhibit the anaerobic digestion process. In this study, a submersible microbial desalination cell (SMDC) was developed as an innovative method to lower the ammonia level in a continuous stirred tank reactor (CSTR) by in situ ammonia...... recovery and electricity production. In batch experiment, the ammonia concentration in the CSTR decreased from 6 to 0.7g-N/L during 30days, resulting in an average recovery rate of 80g-N/m2/d. Meanwhile, a maximum power density of 0.71±0.5W/m2 was generated at 2.85A/m2. Both current driven NH4+ migration...... and free NH3 diffusion were identified as the mechanisms responsible for the ammonia transportation. With an increase in initial ammonia concentration and a decrease in external resistance, the SMDC performance was enhanced. In addition, the coexistence of other cations in CSTR or cathode had no negative...

Ammonia volatilization from crop residues and frozen green manure crops

Science.gov (United States)

de Ruijter, F. J.; Huijsmans, J. F. M.; Rutgers, B.

2010-09-01

Agricultural systems can lose substantial amounts of nitrogen (N). To protect the environment, the European Union (EU) has adopted several directives that set goals to limit N losses. National Emission Ceilings (NEC) are prescribed in the NEC directive for nitrogen oxides and ammonia. Crop residues may contribute to ammonia volatilization, but sufficient information on their contribution to the national ammonia volatilization is lacking. Experiments were carried out with the aim to assess the ammonia volatilization of crop residues left on the soil surface or incorporated into the soil under the conditions met in practice in the Netherlands during late autumn and winter. Ammonia emission from residues of broccoli, leek, sugar beet, cut grass, fodder radish (fresh and frozen) and yellow mustard (frozen) was studied during two winter seasons using volatilization chambers. Residues were either placed on top of soil or mixed with soil. Mixing residues with soil gave insignificant ammonia volatilization, whereas volatilization was 5-16 percent of the N content of residues when placed on top of soil. Ammonia volatilization started after at least 4 days. Total ammonia volatilization was related to C/N-ratio and N concentration of the plant material. After 37 days, cumulative ammonia volatilization was negligible from plant material with N concentration below 2 percent, and was 10 percent of the N content of plant material with 4 percent N. These observations can be explained by decomposition of plant material by micro-organisms. After an initial built up of the microbial population, NH 4+ that is not needed for their own growth is released and can easily emit as NH 3 at the soil surface. The results of the experiments were used to estimate the contribution of crop residues to ammonia volatilization in the Netherlands. Crop residues of arable crops and residues of pasture topping may contribute more than 3 million kg NH 3-N to the national ammonia volatilization of the

IRIS Toxicological Review of Ammonia Noncancer Inhalation (Interagency Science Discussion Draft)

Science.gov (United States)

In September 2016, EPA finalized the IRIS assessment of Ammonia (Noncancer Inhalation). The Toxicological Review was reviewed internally by EPA and by other federal agencies and White House Offices before public release in June 2016. Consistent with the May 2009 IRIS assessment d...

Respiratory ammonia output and blood ammonia concentration during incremental exercise

NARCIS (Netherlands)

Ament, W; Huizenga, [No Value; Kort, E; van der Mark, TW; Grevink, RG; Verkerke, GJ

The aim of this study was to investigate whether the increase of ammonia concentration and lactate concentration in blood was accompanied by an increased expiration of ammonia during graded exercise. Eleven healthy subjects performed an incremental cycle ergometer test. Blood ammonia, blood lactate

Birth control - slow release methods

Science.gov (United States)

Contraception - slow-release hormonal methods; Progestin implants; Progestin injections; Skin patch; Vaginal ring ... might want to consider a different birth control method. SKIN PATCH The skin patch is placed on ...

The role of ammonia in the chemistry of atmospheric aerosols

International Nuclear Information System (INIS)

Brosset, C.

1979-01-01

Data is presented on the concentrations of hydrogen and ammonium ions in aerosol samples taken under various meteorological conditions in different areas of Sweden, and implications for the atmospheric chemistry of aerosols are discussed. Particle compositions at coastal and inland stations were determined during situations when particle concentrations increased as much as a hundred times due to atmospheric transport from Europe or air movements from the east or west. Analysis of particle compositions during both types of particle episodes reveals variations in the H(+)/NH4(+) ratio which indicate that particles present over agricultural areas take up ammonia from the ground and release it over a forest district with acid lakes. The ratio is found to be dependent on the atmospheric partial pressure of ammonia at equilibrium, with the flow of ammonia to or from the ground and transport conditions also likely to influence the ratio

Review of Options for Ammonia/Ammonium Management

Energy Technology Data Exchange (ETDEWEB)

Nash, C. A. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2016-05-06

This report is a review of literature supporting practical ammonia/ammonium destruction processes. Melter research supporting Hanford Low Activity Waste (LAW) glass production has shown that significant amounts of ammonia will be in the melter offgas condensate. Further work with secondary waste forms indicates the potential need to remove the ammonia, perhaps by an oxidative process. This review finds likely practical chemical methods to oxidize ammonia in aqueous solution at moderate temperatures and atmospheric pressure, using easily obtained reagents. Leading candidates include nitrite oxidation to produce nitrogen gas, various peroxide oxidative processes, and air stripping. This work reviews many other processes and provides reasoning to not consider those processes further for this application.

Converting Wind Energy to Ammonia at Lower Pressure

International Nuclear Information System (INIS)

Malmali, Mahdi; Reese, Michael; McCormick, Alon V.; Cussler, E. L.

2017-01-01

Renewable wind energy can be used to make ammonia. However, wind-generated ammonia costs about twice that made from a traditional fossil-fuel driven process. To reduce the production cost, we replace the conventional ammonia condensation with a selective absorber containing metal halides, e.g., calcium chloride, operating at near synthesis temperatures. With this reaction-absorption process, ammonia can be synthesized at 20 bar from air, water, and wind-generated electricity, with rates comparable to the conventional process running at 150–300 bar. In our reaction-absorption process, the rate of ammonia synthesis is now controlled not by the chemical reaction but largely by the pump used to recycle the unreacted gases. The results suggest an alternative route to distributed ammonia manufacture which can locally supply nitrogen fertilizer and also a method to capture stranded wind energy as a carbon-neutral liquid fuel.

Factors affecting the removal of ammonia from air on carbonaceous materials: Investigation of reactive adsorption mechanism

Science.gov (United States)

Petit, Camille

Air pollution related to the release of industrial toxic gases, represents one of the main concerns of our modern world owing to its detrimental effect on the environment. To tackle this growing issue, efficient ways to reduce/control the release of pollutants are required. Adsorption of gases on porous materials appears as a potential solution. However, the physisorption of small molecules of gases such as ammonia is limited at ambient conditions. For their removal, adsorbents providing strong adsorption forces must be used/developed. In this study, new carbon-based materials are prepared and tested for ammonia adsorption at ambient conditions. Characterization of the adsorbents' texture and surface chemistry is performed before and after exposure to ammonia to identify the features responsible for high adsorption capacity and for controlling the mechanisms of retention. The characterization techniques include: nitrogen adsorption, thermal analysis, potentiometric titration, FT-IR spectroscopy, X-ray diffraction, Energy Dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy and Electron Microscopy. The results obtained indicate that ammonia removal is governed by the adsorbent's surface chemistry. On the contrary, porosity (and thus physisorption) plays a secondary role in this process, unless strong dispersive forces are provided by the adsorbent. The surface chemistry features responsible for the enhanced ammonia adsorption include the presence of oxygen-(carboxyl, hydroxyl, epoxy) and sulfur- (sulfonic) containing groups. Metallic species improve the breakthrough capacity as well as they lead to the formation of Lewis acid-base interactions, hydrogen-bonding or complexation. In addition to the latter three mechanisms, ammonia is retained on the adsorbent surface via Bronsted acid-base interactions or via specific reactions with the adsorbent's functionalities leading to the incorporation of ammonia into the adsorbent's matrix. Another mechanism

Experimental study of mixed additive of Ni(II) and piperazine on ammonia escape in CO2 capture using ammonia solution

International Nuclear Information System (INIS)

Ma, Shuangchen; Chen, Gongda; Zhu, Sijie; Wen, Jiaqi; Gao, Ran; Ma, Lan; Chai, Jin

2016-01-01

Highlights: • Compound additive was used to obtain high CO 2 absorption efficiency and low NH 3 escape. • Both organic material and metal ion were applied as compound additive. • Influences of additives on CO 2 absorption and NH 3 escape were investigated. • Possible mechanism and products were analyzed by XRD and UV–visible spectrophotometer. - Abstract: In order to obtain high CO 2 absorption efficiency and low ammonia escape rate, mixed additives of piperazine and Ni(II) were used as absorbent in bubbling reactor. The effects of mixed additive on CO 2 absorption efficiency and ammonia escape rate were investigated; the performances of mixed additive in removal process were compared with that of pure ammonia solution. The proposed mechanism was analyzed by XRD and UV–visible spectrophotometer. The mixed additive has well effect on CO 2 absorption efficiency and ammonia escape reduction. The CO 2 absorption efficiency was 72% when 2 wt% ammonia solution mixed with 0.025 mol/L piperazine and 0.05 mol/L Ni(II), higher than that achieved by 3 wt% ammonia solution without additive, and the amount of ammonia loss was nearly 1/3 compared with 3 wt% pure ammonia solution. This paper provided one feasible method which is beneficial to the balance between CO 2 absorption and ammonia escape in CO 2 capture process.

Nitrocarburizing in ammonia-hydrocarbon gas mixtures

DEFF Research Database (Denmark)

Pedersen, Hanne; Christiansen, Thomas; Somers, Marcel A. J.

2011-01-01

The present work investigates the possibility of nitrocarburising in ammonia-acetylene-hydrogen and ammonia-propene-hydrogen gas mixtures, where unsaturated hydrocarbon gas is the carbon source during nitrocarburising. Consequently, nitrocarburising is carried out in a reducing atmosphere...... microscopy and X-ray diffraction analysis. It is shown that the use of unsaturated hydrocarbon gas in nitrocarburising processes is a viable alternative to traditional nitrocarburising methods....

Decreased astrocytic thrombospondin-1 secretion after chronic ammonia treatment reduces the level of synaptic proteins: in vitro and in vivo studies.

Science.gov (United States)

Jayakumar, Arumugam R; Tong, Xiao Y; Curtis, Kevin M; Ruiz-Cordero, Roberto; Shamaladevi, Nagarajarao; Abuzamel, Missa; Johnstone, Joshua; Gaidosh, Gabriel; Rama Rao, Kakulavarapu V; Norenberg, Michael D

2014-11-01

Chronic hepatic encephalopathy (CHE) is a major complication in patients with severe liver disease. Elevated blood and brain ammonia levels have been implicated in its pathogenesis, and astrocytes are the principal neural cells involved in this disorder. Since defective synthesis and release of astrocytic factors have been shown to impair synaptic integrity in other neurological conditions, we examined whether thrombospondin-1 (TSP-1), an astrocytic factor involved in the maintenance of synaptic integrity, is also altered in CHE. Cultured astrocytes were exposed to ammonia (NH₄Cl, 0.5-2.5 mM) for 1-10 days, and TSP-1 content was measured in cell extracts and culture media. Astrocytes exposed to ammonia exhibited a reduction in intra- and extracellular TSP-1 levels. Exposure of cultured neurons to conditioned media from ammonia-treated astrocytes showed a decrease in synaptophysin, PSD95, and synaptotagmin levels. Conditioned media from TSP-1 over-expressing astrocytes that were treated with ammonia, when added to cultured neurons, reversed the decline in synaptic proteins. Recombinant TSP-1 similarly reversed the decrease in synaptic proteins. Metformin, an agent known to increase TSP-1 synthesis in other cell types, also reversed the ammonia-induced TSP-1 reduction. Likewise, we found a significant decline in TSP-1 level in cortical astrocytes, as well as a reduction in synaptophysin content in vivo in a rat model of CHE. These findings suggest that TSP-1 may represent an important therapeutic target for CHE. Defective release of astrocytic factors may impair synaptic integrity in chronic hepatic encephalopathy. We found a reduction in the release of the astrocytic matricellular proteins thrombospondin-1 (TSP-1) in ammonia-treated astrocytes; such reduction was associated with a decrease in synaptic proteins caused by conditioned media from ammonia-treated astrocytes. Exposure of neurons to CM from ammonia-treated astrocytes, in which TSP-1 is over

U.S. broiler housing ammonia emissions inventory

Science.gov (United States)

Gates, R. S.; Casey, K. D.; Wheeler, E. F.; Xin, H.; Pescatore, A. J.

Using recently published baseline ammonia emissions data for U.S. broiler chicken housing, we present a method of estimating their contribution to an annual ammonia budget that is different from that used by USEPA. Emission rate increases in a linear relationship with flock age from near zero at the start of the flock to a maximum at the end of the flock, 28-65 days later. Market weight of chickens raised for meat varies from "broilers" weighing about 2 kg to "roasters" weighing about 3 kg. Multiple flocks of birds are grown in a single house annually, with variable downtime to prepare the house between flocks. The method takes into account weight and number of chickens marketed. Uncertainty in baseline emissions estimates is used so that inventory estimates are provided with error estimates. The method also incorporates the condition of litter that birds are raised upon and the varying market weight of birds grown. Using 2003 USDA data on broiler production numbers, broiler housing is estimated to contribute 8.8-11.7 kT ammonia for new and built-up litter, respectively, in Kentucky and 240-324 kT ammonia for new and built-up litter, respectively, nationally. Results suggest that a 10% uncertainty in annual emission rate is expected for the market weight categories of broilers, heavy broilers, and roasters. A 27-47% reduction in annual housing emission rate is predicted if new rather than built-up litter were used for every flock. The estimating method can be adapted to other meat bird building emissions and future ammonia emission strategies, with suitable insertion of an age-dependent emission factor or slope into a predictive model equation. The method can be readily applied and is an alternative to that used by USEPA.

Basics of ammonia slip measurement at the flue gas exit of boilers; Grundlagen zur Ammoniak-Schlupfmessung am Kesselende

Energy Technology Data Exchange (ETDEWEB)

Krueger, Sascha [IBK-Verfahrenstechnik, Bad Berka (Germany); Krueger, Joerg [VWT Ing.-Buero, Schwandorf (Germany); Karau, Friedrich [Industrieberatung Karau, Wetzlar (Germany)

2013-09-01

When using SNCR in WtE-, biomass- and RDF combustion plants, it is not only the reduction rate of nitrogen oxide in the flue gas which is important to control but also the adherence to the limiting values for ammonia slip. Ammonia concentration in the flue gas upstream of stack is of course always in the operators' focus as limiting values have to be hold. Measuring ammonia in the flue gas downstream of boiler is not trivial due to behaviour of ammonia which occurs in bonded state (compounds) in significant amounts also at flue gas temperatures above 400 C. Ammonia compounds can occur on one hand as chemical compounds e.g. to chlorine as ammonium chlorine (chemical bonding) and on the other hand they can occur bonded to surfaces (physically adsorbed). Basic additives of the dry and quasi dry flue gas treatment cause the fractional release of bounded ammonia, therefore, after flue gas treatment, the ammonia slip can be partially measured. (orig.)

Lignin solubilisation and gentle fractionation in liquid ammonia

NARCIS (Netherlands)

Strassberger, Z.; Prinsen, P.; Klis, van der F.; Es, van D.S.; Tanase, S.; Rothenberg, G.

2015-01-01

We present a simple method for solubilising lignin using liquid ammonia. Unlike water, which requires harsh conditions, ammonia can solubilise technical lignins, in particular kraft lignin. A commercial pine wood Kraft lignin (Indulin AT) was solubilized instantaneously at room temperature and 7–11

Characterizing the Performance of Gas-Permeable Membranes as an Ammonia Recovery Strategy from Anaerobically Digested Dairy Manure.

Science.gov (United States)

Fillingham, Melanie; VanderZaag, Andrew; Singh, Jessica; Burtt, Stephen; Crolla, Anna; Kinsley, Chris; MacDonald, J Douglas

2017-10-07

Capturing ammonia from anaerobically digested manure could simultaneously decrease the adverse effects of ammonia inhibition on biogas production, reduce reactive nitrogen (N) loss to the environment, and produce mineral N fertilizer as a by-product. In this study, gas permeable membranes (GPM) were used to capture ammonia from dairy manure and digestate by the diffusion of gaseous ammonia across the membrane where ammonia is captured by diluted acid, forming an aqueous ammonium salt. A lab-scale prototype using tubular expanded polytetrafluoroethylene (ePTFE) GPM was used to (1) characterize the effect of total ammonium nitrogen (TAN) concentration, temperature, and pH on the ammonia capture rate using GPM, and (2) to evaluate the performance of a GPM system in conditions similar to a mesophilic anaerobic digester. The GPM captured ammonia at a rate between 2.2 to 6.3% of gaseous ammonia in the donor solution per day. Capture rate was faster in anaerobic digestate than raw manure. The ammonia capture rate could be predicted using non-linear regression based on the factors of total ammonium nitrogen concentration, temperature, and pH. This use of membranes shows promise in reducing the deleterious impacts of ammonia on both the efficiency of biogas production and the release of reactive N to the environment.

Evaluation of ammonia-borane as a laser-fusion-target material. Final progress report, March 1, 1978-May 31, 1978

International Nuclear Information System (INIS)

Geanangel, R.A.

1978-01-01

Significant results from the previous three quarterly reports are reviewed. Ammonia-borane should be zone sublimed prior to use in fabrication experiments because it is found to undergo an unspecified decomposition which lowers the melting point but does not release significant amounts of hydrogen. Ammonia-borane microballoons, formed by the liquid droplet method, were mounted on glass stalks using epoxy cement and inspected by optical and electron microscopy. Microballoons which had been gold-coated showed expansion and severe surface cracking not visible in optical micrographs or in electron micrographs of uncoated shells. Heating from gold deposition is believed to be responsible for the degradation. Several good quality microballoons were observed. Uncoated, these showed no expansion or surface cracking in the vacuum of the SEM

Transcriptional Response of the Archaeal Ammonia Oxidizer Nitrosopumilus maritimus to Low and Environmentally Relevant Ammonia Concentrations

Science.gov (United States)

Stahl, David A.

2013-01-01

The ability of chemoautotrophic ammonia-oxidizing archaea to compete for ammonia among marine microorganisms at low ambient concentrations has been in part attributed to their extremely high affinity for ammonia, but as yet there is no mechanistic understanding of supporting metabolism. We examined transcription of selected genes for anabolic functions (CO2 fixation, ammonia transport, and cell wall synthesis) and a central catabolic function (ammonia oxidation) in the thaumarchaeon Nitrosopumilus maritimus SCM1 growing at two ammonia concentrations, as measured by combined ammonia and ammonium, one well above the Km for ammonia oxidation (∼500 μM) and the other well below the Km (ammonia-replete to ammonia-limiting conditions. Transcript levels for ammonia oxidation, CO2 fixation, and one of the ammonia transport genes were approximately the same at high and low ammonia availability. Transcripts for all analyzed genes decreased with time in the complete absence of ammonia, but with various rates of decay. The new steady-state mRNA levels established are presumably more reflective of the natural physiological state of ammonia-oxidizing archaea and offer a reference for interpreting message abundance patterns in the natural environment. PMID:23995944

Moderating effect of ammonia on particle growth and stability of quasi-monodisperse silver nanoparticles synthesized by the Turkevich method.

Science.gov (United States)

Gorup, Luiz F; Longo, Elson; Leite, Edson R; Camargo, Emerson R

2011-08-15

A new method to stabilize silver nanoparticles by the addition of ammonia is proposed. Colloidal dispersions of silver nanoparticles were synthesized by the Turkevich method using sodium citrate to reduce silver nitrate at high pH and at 90 °C. After approximately 12 min, a diluted ammonia solution was added to the reaction flask to form soluble diamine silver (I) complexes that played an important growth moderating role, making it possible to stabilize metallic silver nanoparticles with sizes as small as 1.6 nm after 17 min of reaction. Colloidal dispersions were characterized by UV-visible absorption spectroscopy, X-ray diffraction, and transmission electronic microscopy. Copyright © 2011 Elsevier Inc. All rights reserved.

Properties and possibilities to use by-product from e-beam installations for partial recycling of ammonia

Energy Technology Data Exchange (ETDEWEB)

Pelovski, Y. [University of Chemical Technology and Metallurgy, Sofia (Bulgaria)

2011-07-01

Generated by-products from E-beam cleaning systems of industrial waste gases have been studied using different techniques like TG-DTA systems, Electron Microscopy, X-Ray diffraction and IR spectroscopy methods. On the base of the investigations it was found that the composition of the by-product varies depending on the content of pollutants in the waste gases and technological parameters during cleaning process. Size of particles and thermal stability of the by product were determined. Content of ammonium sulphate as a main component, ammonium nitrate and heavy metals content is also determined and discussed. During thermal treatment of the by-product at temperature range 543-663K half of the ammonia is released in the gas phase. Kinetic parameters of the thermal decomposition are determined and it is confirmed that for waste gases containing mainly SO{sub x} as a pollutants they are very close to the pure ammonium sulphate. By-product from demonstration E-beam installation at Maritsa-East -2 TPP is used to produce mixed fertilisers using milled Tunisia phosphorites or tribo-activated mixtures of the by-product, Tunisia phosphorite, potassium sulphate and aches from electrostatic precipitators of TPP. It was found that during thermo-tribochemical treatment of selected mixtures different type of fertilisers could be produced, where the soluble forms of Phosphorous may vary, depending on the conditions. During thermal treatment about half of ammonia is released in the gas phase opening a way for partial recycling of ammonia to the cleaning process. Agrochemical tests of the fertilisers on the base of by-product confirm their efficiency. (author)

Properties and possibilities to use by-product from e-beam installations for partial recycling of ammonia

International Nuclear Information System (INIS)

Pelovski, Y.

2011-01-01

Generated by-products from E-beam cleaning systems of industrial waste gases have been studied using different techniques like TG-DTA systems, Electron Microscopy, X-Ray diffraction and IR spectroscopy methods. On the base of the investigations it was found that the composition of the by-product varies depending on the content of pollutants in the waste gases and technological parameters during cleaning process. Size of particles and thermal stability of the by product were determined. Content of ammonium sulphate as a main component, ammonium nitrate and heavy metals content is also determined and discussed. During thermal treatment of the by-product at temperature range 543-663K half of the ammonia is released in the gas phase. Kinetic parameters of the thermal decomposition are determined and it is confirmed that for waste gases containing mainly SO x as a pollutants they are very close to the pure ammonium sulphate. By-product from demonstration E-beam installation at Maritsa-East -2 TPP is used to produce mixed fertilisers using milled Tunisia phosphorites or tribo-activated mixtures of the by-product, Tunisia phosphorite, potassium sulphate and aches from electrostatic precipitators of TPP. It was found that during thermo-tribochemical treatment of selected mixtures different type of fertilisers could be produced, where the soluble forms of Phosphorous may vary, depending on the conditions. During thermal treatment about half of ammonia is released in the gas phase opening a way for partial recycling of ammonia to the cleaning process. Agrochemical tests of the fertilisers on the base of by-product confirm their efficiency. (author)

Ammonia chemistry at SMART

International Nuclear Information System (INIS)

Na, J. W.; Seong, G. W.; Lee, E. H.; Kim, W. C.; Choi, B. S.; Kim, J. P.; Lee, D. J.

1999-01-01

Ammonia is used as the pH control agent of primary water at SMART (System-integrated Modular Advanced ReacTor). Some of this ammonia is decomposed to hydrogen and nitrogen by radiation in the reactor core. The produced hydrogen gas is used for the removal of dissolved oxygen in the coolant. Some of nitrogen gas in pressurizer is dissolved into the primary water. Because ammonia, hydrogen and nitrogen which is produced by ammonia radiolysis are exist in the coolant at SMART, ammonia chemistry at SMART is different with lithium-boron chemistry at commercial PWR. In this study, the pH characteristics of ammonia and the solubility characteristics of hydrogen and nytrogen were analyzed for the management of primary water chemistry at SMART

A study on synthetic method and material characteristics of magnesium ammine chloride as ammonia transport materials for solid SCR

Energy Technology Data Exchange (ETDEWEB)

Shin, Jong Kook; Yoon, Cheon Seog [Dept. of Mechanical Engineering, Hannam University, Daejeon (Korea, Republic of); Kim, Hong Suk [Engine Research Center, Korea Institute of Machinery and Materials, Daejeon (Korea, Republic of)

2015-11-15

Among various ammonium salts and metal ammine chlorides used as solid materials for the sources of ammonia with solid SCR for lean NOx reduction, magnesium ammine chloride was taken up for study in this paper because of its ease of handling and safety. Lab-scale synthetic method of magnesium ammine chloride were studied for different durations, temperatures, and pressures with proper ammonia gas charged, as a respect of ammonia gas adsorption rate(%). To understand material characteristics for lab-made magnesium ammine chloride, DA, IC, FT-IR, XRD and SDT analyses were performed using the published data available in literature. From the analytical results, the water content in the lab-made magnesium ammine chloride can be determined. A new test procedure for water removal was proposed, by which the adsorption rate of lab-made sample was found to be approximately 100%.

A study on synthetic method and material characteristics of magnesium ammine chloride as ammonia transport materials for solid SCR

International Nuclear Information System (INIS)

Shin, Jong Kook; Yoon, Cheon Seog; Kim, Hong Suk

2015-01-01

Among various ammonium salts and metal ammine chlorides used as solid materials for the sources of ammonia with solid SCR for lean NOx reduction, magnesium ammine chloride was taken up for study in this paper because of its ease of handling and safety. Lab-scale synthetic method of magnesium ammine chloride were studied for different durations, temperatures, and pressures with proper ammonia gas charged, as a respect of ammonia gas adsorption rate(%). To understand material characteristics for lab-made magnesium ammine chloride, DA, IC, FT-IR, XRD and SDT analyses were performed using the published data available in literature. From the analytical results, the water content in the lab-made magnesium ammine chloride can be determined. A new test procedure for water removal was proposed, by which the adsorption rate of lab-made sample was found to be approximately 100%

The acute effect of cannabis on plasma, liver and brain ammonia dynamics, a translational study.

Science.gov (United States)

Abulseoud, Osama A; Zuccoli, Maria Laura; Zhang, Lifeng; Barnes, Allan; Huestis, Marilyn A; Lin, Da-Ting

2017-07-01

Recent reports of ammonia released during cannabis smoking raise concerns about putative neurotoxic effects. Cannabis (54mg) was administered in a double-blind, placebo-controlled design to healthy cannabis users (n=15) either orally, or through smoking (6.9%THC cigarette) or inhalation of vaporized cannabis (Volcano®). Serial assay of plasma ammonia concentrations at 0, 2, 4, 6, 8, 10, 15, 30, and 90min from onset of cannabis administration showed significant time (P=0.016), and treatment (P=0.0004) effects with robust differences between placebo and edible at 30 (P=0.002), and 90min (P=0.007) and between placebo and vaporized (P=0.02) and smoking routes (P=0.01) at 90min. Furthermore, plasma ammonia positively correlated with blood THC concentrations (P=0.03). To test the hypothesis that this delayed increase in plasma ammonia originates from the brain we administered THC (3 and 10mg/kg) to mice and measured plasma, liver, and brain ammonia concentrations at 1, 3, 5 and 30min post-injection. Administration of THC to mice did not cause significant change in plasma ammonia concentrations within the first 5min, but significantly reduced striatal glutamine-synthetase (GS) activity (P=0.046) and increased striatal ammonia concentration (P=0.016). Furthermore, plasma THC correlated positively with striatal ammonia concentration (Pcannabis intake caused time and route-dependent increases in plasma ammonia concentrations in human cannabis users and reduced brain GS activity and increased brain and plasma ammonia concentrations in mice. Published by Elsevier B.V.

The effect of gaseous ammonia on cobalt perrhenate

International Nuclear Information System (INIS)

Maslov, L.P.; Men'shikov, O.D.; Borisov, V.V.; Sorokin, S.I.; Krutovertsev, S.A.; Kharkevich, S.I.; Ivanova, O.M.

1994-01-01

The influence of humid air ammonia mixture on crystal pentahydrate of cobalt(2) perrhenate has been studied by the methods of PES, IR spectroscopy thermal analysis and electrophysical measurements. It is shown that with an increase in ammonia content in gaseous phase cobalt perrhenate successively transforms into diaquodiammine-, tetrammine- and μ-dioxo-bis-(tetrammine) derivatives of cobalt. Reversibility of dioxocomplex formation and a correlation between the change in electrophysical properties of crystal sample and change in ammonia content in gaseous phase are pointed out. 16 refs.; 4 figs.; 1 tab

Evaluation of a third party enzymatic ammonia method for use on the Roche Cobas 6000 (c501) automated platform.

Science.gov (United States)

Seiden-Long, Isolde; Schnabl, Kareena; Skoropadyk, Wendy; Lennon, Nola; McKeage, Arlayne

2014-08-01

Adaptation of the Randox Enzymatic Manual UV Ammonia method to be used on the Roche Cobas 6000 (c501) automated analyzer platform. The Randox ammonia reagent was evaluated for precision, linearity, accuracy and interference from hemolysis, icterus and lipemia on the Roche c501 analyzer. Comparison studies were conducted for the Randox reagent between Roche c501, Siemens Vista, Ortho Vitros 250, and Beckman DxC methods. The Randox reagent demonstrates acceptable within-run (L1=65 μmol/L, CV 3.4% L2=168 μmol/L, CV 1.9%) and between-run precision (L1=29 μmol/L, CV 7.3% L2=102 μmol/L, CV 3.0%), Analytical Measurement Range (7-940 μmol/L), and accuracy. The method interference profile is superior for the Randox method (hemolysis index up to 600, icteric index up to 60, lipemic index up to 100) as compared to the Roche method (hemolysis index up to 200, icteric index up to 10, lipemic index up to 50). Comparison was very good between the Randox reagent and two other wet chemistry platforms. The Randox Enzymatic Manual UV Ammonia reagent is an available alternative to the Roche Cobas c501 reagent. The method is more robust to endogenous interferences and less prone to instrument error flags, thus allowing the majority of clinical specimens to be reported without additional sample handling at our institution. Copyright © 2014 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

AMINA-chip : a miniaturized measurement system for ambient ammonia

NARCIS (Netherlands)

Timmer, Björn Herman

2004-01-01

The development of a miniaturized and integrated measurement system for gaseous ammonia is described in this thesis. The measuring principle, ¿AMINA¿, is an indirect method for selectively measuring ammonia that makes use of pH-transitions, electrolyte conductivity detection and phaseseparating

Treating electrolytic manganese residue with alkaline additives for stabilizing manganese and removing ammonia

Energy Technology Data Exchange (ETDEWEB)

Zhou, Changbo; Wang, Jiwei [Chinese Research Academy of Environmental Sciences, Beijing (China); Wang, Nanfang [Hunan Institute of Engineering, Xiangtan (China)

2013-11-15

Electrolytic manganese residue (EMR) from the electrolytic manganese industry is a solid waste containing mainly calcium sulfate dihydrate and quartzite. It is impossible to directly use the EMR as a building material due to some contaminants such as soluble manganese, ammonia nitrogen and other toxic substances. To immobilize the contaminants and reduce their release into the environment, treating EMR using alkaline additives for stabilizing manganese and removing ammonia was investigated. The physical and chemical characteristics of the original EMR were characterized by XRFS, XRD, and SEM. Leaching test of the original EMR shows that the risks to the environment are the high content of soluble manganese and ammonia nitrogen. The influence of various alkaline additives, solidifying reaction time, and other solidifying reaction conditions such as outdoor ventilation and sunlight, and rain flow on the efficiencies of Mn{sup 2+} solidification and ammonia nitrogen removal was investigated. The results show that with mass ratio of CaO to residue 1 : 8, when the solidifying reaction was carried out indoors for 4 h with no rain flow, the highest efficiencies of Mn{sup 2+} solidification and ammonia nitrogen removal (99.98% and 99.21%) are obtained. Leaching test shows that the concentration and emission of manganese and ammonia nitrogen of the treated EMR meets the requirements of the Chinese government legislation (GB8978-1996)

Treating electrolytic manganese residue with alkaline additives for stabilizing manganese and removing ammonia

International Nuclear Information System (INIS)

Zhou, Changbo; Wang, Jiwei; Wang, Nanfang

2013-01-01

Electrolytic manganese residue (EMR) from the electrolytic manganese industry is a solid waste containing mainly calcium sulfate dihydrate and quartzite. It is impossible to directly use the EMR as a building material due to some contaminants such as soluble manganese, ammonia nitrogen and other toxic substances. To immobilize the contaminants and reduce their release into the environment, treating EMR using alkaline additives for stabilizing manganese and removing ammonia was investigated. The physical and chemical characteristics of the original EMR were characterized by XRFS, XRD, and SEM. Leaching test of the original EMR shows that the risks to the environment are the high content of soluble manganese and ammonia nitrogen. The influence of various alkaline additives, solidifying reaction time, and other solidifying reaction conditions such as outdoor ventilation and sunlight, and rain flow on the efficiencies of Mn"2"+ solidification and ammonia nitrogen removal was investigated. The results show that with mass ratio of CaO to residue 1 : 8, when the solidifying reaction was carried out indoors for 4 h with no rain flow, the highest efficiencies of Mn"2"+ solidification and ammonia nitrogen removal (99.98% and 99.21%) are obtained. Leaching test shows that the concentration and emission of manganese and ammonia nitrogen of the treated EMR meets the requirements of the Chinese government legislation (GB8978-1996)

Ammonia release from heated "street" cannabis leaf and its potential toxic effects on cannabis users

Czech Academy of Sciences Publication Activity Database

Bloor, R.; Wang, T. S.; Španěl, Patrik; Smith, D.

2008-01-01

Roč. 103, č. 10 (2008), s. 1671-1677 ISSN 0965-2140 Institutional research plan: CEZ:AV0Z40400503 Keywords : ammonia * cannabis * respiratory Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.244, year: 2008

Ammonia concentrations in canine whole blood, EDTA-anticoagulated whole blood, and plasma measured by use of a point-of-care ammonia meter.

Science.gov (United States)

Odunayo, Adesola; Tobias, Karen M; Okafor, Chika C; Flatland, Bente

2017-11-01

OBJECTIVE To investigate the use of canine whole blood (WB) for measurement of ammonia concentration by use of a point-of-care ammonia meter and to compare results of measuring ammonia concentrations in WB, EDTA-anticoagulated WB, and plasma. ANIMALS 40 client-owned dogs. PROCEDURES A blood sample (2 mL) was obtained from each dog. One drop of WB was immediately applied to a test strip for evaluation with an ammonia meter. The remainder of the blood sample was placed in an EDTA-containing tube, and 1 drop of EDTA-anticoagulated WB was applied to a test strip. The remaining EDTA-anticoagulated WB sample was centrifuged, and the plasma was harvested and placed on ice. One drop of plasma was applied to a test strip; the remainder of the plasma sample was transported on ice and used for ammonia measurement with a reference laboratory instrument. All samples were tested within 1 hour after sample collection. Results were evaluated to detect significant differences in ammonia concentration. RESULTS Ammonia concentrations did not differ significantly between WB and EDTA-anticoagulated WB and between plasma samples measured with the meter and reference laboratory instrument. However, median ammonia concentration was significantly higher in plasma than in WB or EDTA-anti-coagulated WB. CONCLUSIONS AND CLINICAL RELEVANCE Anticoagulant-free WB was a valid sample for measurement by use of the ammonia meter. Plasma samples had higher ammonia concentrations than did WB samples. Results for each sample type should be interpreted by use of specimen- and method-specific reference intervals.

Hydration of ammonia, methylamine, and methanol in amorphous solid water

Science.gov (United States)

Souda, Ryutaro

2016-02-01

Interactions of polar protic molecules with amorphous solid water (ASW) have been investigated using temperature-programmed desorption and time-of-flight secondary ion mass spectrometry. The ammonia and methylamine are incorporated into the interior of porous ASW films. They are caged by water molecules and are released during water crystallization. In contrast, the methanol-water interaction is not influenced by pores of ASW. The methanol additives tend to survive water crystallization and are released during ASW film evaporation. The hydration of n-hexane in ASW is influenced significantly by methanol additives because n-hexane is accommodated in a methanol-induced hydration shell.

Dihydrogen Phosphate Stabilized Ruthenium(0 Nanoparticles: Efficient Nanocatalyst for The Hydrolysis of Ammonia-Borane at Room Temperature

Directory of Open Access Journals (Sweden)

Feyyaz Durap

2015-07-01

Full Text Available Intensive efforts have been devoted to the development of new materials for safe and efficient hydrogen storage. Among them, ammonia-borane appears to be a promising candidate due to its high gravimetric hydrogen storage capacity. Ammonia-borane can release hydrogen on hydrolysis in aqueous solution under mild conditions in the presence of a suitable catalyst. Herein, we report the synthesis of ruthenium(0 nanoparticles stabilized by dihydrogenphosphate anions with an average particle size of 2.9 ± 0.9 nm acting as a water-dispersible nanocatalyst in the hydrolysis of ammonia-borane. They provide an initial turnover frequency (TOF value of 80 min−1 in hydrogen generation from the hydrolysis of ammonia-borane at room temperature. Moreover, the high stability of these ruthenium(0 nanoparticles makes them long-lived and reusable nanocatalysts for the hydrolysis of ammonia-borane. They provide 56,800 total turnovers and retain ~80% of their initial activity even at the fifth catalytic run in the hydrolysis of ammonia-borane at room temperature.

Dihydrogen Phosphate Stabilized Ruthenium(0) Nanoparticles: Efficient Nanocatalyst for The Hydrolysis of Ammonia-Borane at Room Temperature

Science.gov (United States)

Durap, Feyyaz; Caliskan, Salim; Özkar, Saim; Karakas, Kadir; Zahmakiran, Mehmet

2015-01-01

Intensive efforts have been devoted to the development of new materials for safe and efficient hydrogen storage. Among them, ammonia-borane appears to be a promising candidate due to its high gravimetric hydrogen storage capacity. Ammonia-borane can release hydrogen on hydrolysis in aqueous solution under mild conditions in the presence of a suitable catalyst. Herein, we report the synthesis of ruthenium(0) nanoparticles stabilized by dihydrogenphosphate anions with an average particle size of 2.9 ± 0.9 nm acting as a water-dispersible nanocatalyst in the hydrolysis of ammonia-borane. They provide an initial turnover frequency (TOF) value of 80 min−1 in hydrogen generation from the hydrolysis of ammonia-borane at room temperature. Moreover, the high stability of these ruthenium(0) nanoparticles makes them long-lived and reusable nanocatalysts for the hydrolysis of ammonia-borane. They provide 56,800 total turnovers and retain ~80% of their initial activity even at the fifth catalytic run in the hydrolysis of ammonia-borane at room temperature. PMID:28793435

Haber Process for Ammonia Synthesis

Indian Academy of Sciences (India)

and production methods for large-scale production of ammonia. The collaborative ... temperature also causes the equilibrium position to move to the right .... From the equilibrium data measured it was obvious ... ity, performance and lifetime.

Clinical utility of breath ammonia for evaluation of ammonia physiology in healthy and cirrhotic adults

Science.gov (United States)

Spacek, Lisa A; Mudalel, Matthew; Tittel, Frank; Risby, Terence H; Solga, Steven F

2016-01-01

Blood ammonia is routinely used in clinical settings to assess systemic ammonia in hepatic encephalopathy and urea cycle disorders. Despite its drawbacks, blood measurement is often used as a comparator in breath studies because it is a standard clinical test. We sought to evaluate sources of measurement error and potential clinical utility of breath ammonia compared to blood ammonia. We measured breath ammonia in real time by quartz enhanced photoacoustic spectrometry and blood ammonia in 10 healthy and 10 cirrhotic participants. Each participant contributed 5 breath samples and blood for ammonia measurement within 1 h. We calculated the coefficient of variation (CV) for 5 breath ammonia values, reported medians of healthy and cirrhotic participants, and used scatterplots to display breath and blood ammonia. For healthy participants, mean age was 22 years (±4), 70% were men, and body mass index (BMI) was 27 (±5). For cirrhotic participants, mean age was 61 years (±8), 60% were men, and BMI was 31 (±7). Median blood ammonia for healthy participants was within normal range, 10 μmol L−1 (interquartile range (IQR), 3–18) versus 46 μmol L−1 (IQR, 23–66) for cirrhotic participants. Median breath ammonia was 379 pmol mL−1 CO2 (IQR, 265–765) for healthy versus 350 pmol mL−1 CO2 (IQR, 180–1013) for cirrhotic participants. CV was 17 ± 6%. There remains an important unmet need in the evaluation of systemic ammonia, and breath measurement continues to demonstrate promise to fulfill this need. Given the many differences between breath and blood ammonia measurement, we examined biological explanations for our findings in healthy and cirrhotic participants. We conclude that based upon these preliminary data breath may offer clinically important information this is not provided by blood ammonia. PMID:26658550

REMOVAL OF AMMONIA TOXCITY IN MARINE SEDIMENT TIES: A COMPARISON OF ULVA LACTUCA, ZEOLITE AND AREATION METHODS

Science.gov (United States)

Ammonia is suspected of causing some of the toxicity observed in marine sediment toxicity tests because it is sometimes found at elevated concentrations in marine interstitial waters. In marine waters, ammonia exists as un-ionized ammonia (NH3) and ammonium (NH4+) which combine ...

Effects of chronic ammonia exposure on ammonia metabolism and excretion in marine medaka Oryzias melastigma.

Science.gov (United States)

Gao, Na; Zhu, Limei; Guo, Zhiqiang; Yi, Meisheng; Zhang, Li

2017-06-01

Ammonia is highly toxic to aquatic organisms, but whether ammonia excretion or ammonia metabolism to less toxic compounds is the major strategy for detoxification in marine fish against chronic ammonia exposure is unclear to date. In this study, we investigated the metabolism and excretion of ammonia in marine medaka Oryzias melastigma during chronic ammonia exposure. The fish were exposed to 0, 0.1, 0.3, 0.6, and 1.1 mmol l -1  NH 4 Cl spiked seawater for 8 weeks. Exposure of 0.3-1.1 mmol l -1  NH 4 Cl had deleterious effects on the fish, including significant reductions in growth, feed intake, and total protein content. However, the fish could take strategies to detoxify ammonia. The tissue ammonia (T Amm ) in the 0.3-1.1 mmol l -1  NH 4 Cl treatments was significantly higher than those in the 0 and 0.1 mmol l -1  NH 4 Cl treatments after 2 weeks of exposure, but it recovered with prolonged exposure time, ultimately reaching the control level after 8 weeks. The amino acid catabolic rate decreased to reduce the gross ammonia production with the increasing ambient ammonia concentration. The concentrations of most metabolites remained constant in the 0-0.6 mmol l -1  NH 4 Cl treatments, whereas 5 amino acids and 3 energy metabolism-related metabolites decreased in the 1.1 mmol l -1  NH 4 Cl treatment. J Amm steadily increased in ambient ammonia from 0 to 0.6 mmol l -1 and slightly decreased when the ambient ammonia concentration increased to 1.1 mmol l -1 . Overall, marine medaka cope with sublethal ammonia environment by regulating the tissue T Amm via reducing the ammonia production and increasing ammonia excretion. Copyright © 2017 Elsevier Ltd. All rights reserved.

DETERMINATION OF AMMONIA IN EAR-LOBE CAPILLARY BLOOD IS AN ALTERNATIVE TO ARTERIAL BLOOD AMMONIA

NARCIS (Netherlands)

HUIZENGA, [No Value; GIPS, CH; CONN, HO; JANSEN, PLM

1995-01-01

Blood ammonia determination is a laboratory test to diagnose hepatic encephalopathy. Arterial blood is superior to peripheral venous blood ammonia because of ammonia metabolism in muscle. We have compared capillary with arterial whole blood ammonia as capillary sampling is an attractive alternative.

Determination of ammonia in ear-lobe capillary blood is an alternative to arterial blood ammonia

NARCIS (Netherlands)

Huizenga, J. R.; Gips, C. H.; Conn, H. O.; Jansen, P. L.

1995-01-01

Blood ammonia determination is a laboratory test to diagnose hepatic encephalopathy. Arterial blood is superior to peripheral venous blood ammonia because of ammonia metabolism in muscle. We have compared capillary with arterial whole blood ammonia as capillary sampling is an attractive alternative.

Exploring FeSe-based superconductors by liquid ammonia method

International Nuclear Information System (INIS)

Ying Tian-Ping; Wang Gang; Jin Shi-Feng; Shen Shi-Jie; Zhang Han; Zhou Ting-Ting; Lai Xiao-Fang; Wang Wan-Yan; Chen Xiao-Long

2013-01-01

Our recent progress on the preparation of a series of new FeSe-based superconductors and the clarification of SC phases in potassium-intercalated iron selenides are reviewed here. By the liquid ammonia method, metals Li, Na, Ca, Sr, Ba, Eu, and Yb are intercalated in between FeSe layers and form superconductors with transition temperatures of 30 K∼46 K, which cannot be obtained by high-temperature routes. In the potassium-intercalated iron selenides, we demonstrate that at least two SC phases exist, K x Fe 2 Se 2 (NH 3 ) y (x ≈ 0.3 and 0.6), determined mainly by the concentration of potassium. NH 3 has little, if any, effect on superconductivity, but plays an important role in stabilizing the structures. All these results provide a new starting point for studying the intrinsic properties of this family of superconductors, especially for their particular electronic structures. (topical review - iron-based high temperature superconductors)

Pilot-scale field study for ammonia removal from lagoon biogas using an acid wet scrubber.

Science.gov (United States)

Lin, Hongjian; Wu, Xiao; Miller, Curtis; Zhu, Jun; Hadlocon, Lara Jane; Manuzon, Roderick; Zhao, Lingying

2014-01-01

The anaerobic activities in swine slurry storage and treatment generate biogas containing gaseous ammonia component which is a chemical agent that can cause adverse environmental impacts when released to the atmosphere. The aim of this pilot plant study was to remove ammonia from biogas generated in a covered lagoon, using a sulfuric acid wet scrubber. The data showed that, on average, the biogas contained 43.7 ppm of ammonia and its concentration was found to be exponentially related to the air temperature inside the lagoon. When the air temperature rose to 35°C and the biogas ammonia concentration reached 90 ppm, the mass transfer of ammonia/ammonium from the deeper liquid body to the interface between the air and liquid became a limiting factor. The biogas velocity was critical in affecting ammonia removal efficiency of the wet scrubber. A biogas flow velocity of 8 to 12 mm s(-1) was recommended to achieve a removal efficiency of greater than 60%. Stepwise regression revealed that the biogas velocity and air temperature, not the inlet ammonia concentration in biogas, affected the ammonia removal efficiency. Overall, when 73 g L(-1) (or 0.75 M) sulfuric acid solution was used as the scrubber solution, removal efficiencies varied from 0% to 100% with an average of 55% over a 40-d measurement period. Mass balance calculation based on ammonium-nitrogen concentration in final scrubber liquid showed that about 21.3 g of ammonia was collected from a total volume of 1169 m(3) of biogas, while the scrubber solution should still maintain its ammonia absorbing ability until its concentration reaches up to 1 M. These results showed promising use of sulfuric acid wet scrubber for ammonia removal in the digester biogas.

BLOOD AMMONIA AND GLUTAMINE AS PREDICTORS OF HYPERAMMONEMIC CRISES IN UREA CYCLE DISORDER PATIENTS

Science.gov (United States)

Lee, Brendan; Diaz, George A.; Rhead, William; Lichter-Konecki, U.; Feigenbaum, Annette; Berry, Susan A.; Le Mons, C.; Bartley, James A; Longo, Nicola; Nagamani, Sandesh C.; Berquist, William; Gallagher, Renata; Bartholomew, Dennis; Harding, Cary O.; Korson, Mark S.; McCandless, Shawn E.; Smith, Wendy; Cederbaum, Stephen; Wong, Derek; Merritt, J. Lawrence; Schulze, A.; Vockley, Gerard.; Kronn, David; Zori, Roberto; Summar, Marshall; Milikien, D.A.; Marino, M.; Coakley, D.F.; Mokhtarani, M.; Scharschmidt, B.F.

2014-01-01

Purpose To examine predictors of ammonia exposure and hyperammonemic crises (HAC) in patients with urea cycle disorders (UCDs). Methods The relationships between fasting ammonia, daily ammonia exposure, and HACs were analyzed in >100 UCD patients. Results Fasting ammonia correlated strongly with daily ammonia exposure (r=0.764, p200% (purea nitrogen. Fasting glutamine correlated weakly with AUC0-24 and was not a significant predictor of HACs. Conclusions Fasting ammonia correlates strongly and positively with daily ammonia exposure and with the risk and rate of HACs, suggesting that UCD patients may benefit from tight ammonia control. PMID:25503497

Fabrication of optical chemical ammonia sensors using anodized alumina supports and sol-gel method.

Science.gov (United States)

Markovics, Akos; Kovács, Barna

2013-05-15

In this comparative study, the fabrication and the sensing properties of various reflectometric optical ammonia gas sensors are described. In the first set of experiments the role of the support material was investigated on four different sensor membranes. Two of them were prepared by the adsorption of bromocresol green indicator on anodized aluminum plates. The applied anodizing voltages were 12 V and 24 V, which resulted in different dynamic ranges and response times for gaseous ammonia. The sol-gel method was used for the preparation of the other batch of sensors. These layers were coated on anodized aluminum plates (24 V) and on standard microscope cover glasses. In spite of the identical sensing chemistry, slightly different response times were measured merely because of the aluminum surface porosity. Gas molecules can remain entrapped in the pores, which results in delayed recovery time. On the other hand, the porous oxide film provides excellent adhesion, making the anodized aluminum an attractive support for the sol-gel layer. Copyright © 2013 Elsevier B.V. All rights reserved.

Bioaugmentation as a solution to increase methane production from an ammonia-rich substrate.

Science.gov (United States)

Fotidis, Ioannis A; Wang, Han; Fiedel, Nicolai R; Luo, Gang; Karakashev, Dimitar B; Angelidaki, Irini

2014-07-01

Ammonia-rich substrates inhibit the anaerobic digestion (AD) process and constitute the main reason for low energy recovery in full-scale reactors. It is estimated that many full-scale AD reactors are operating in ammonia induced "inhibited steady-state" with significant losses of the potential biogas production yield. To date there are not any reliable methods to alleviate the ammonia toxicity effect or to efficiently digest ammonia-rich waste. In the current study, bioaugmentation as a possible method to alleviate ammonia toxicity effect in a mesophilic continuously stirred-tank reactor (CSTR) operating under "inhibited steady state" was tested. A fast growing hydrogenotrophic methanogen (i.e., Methanoculleus bourgensis MS2(T)) was bioaugmented in the CSTR reactor at high ammonia levels (5 g NH4(+)-N L(-1)). A second CSTR reactor was used as control with no bioaugmentation. The results derived from this study clearly demonstrated a 31.3% increase in methane production yield in the CSTR reactor, at steady-state, after bioaugmentation. Additionally, high-throughput 16S rRNA gene sequencing analysis showed a 5-fold increase in relative abundance of Methanoculleus spp. after bioaugmentation. On the contrary to all methods used today to alleviate ammonia toxicity effect, the tested bioaugmentation process performed without interrupting the continuous operation of the reactor and without replacing the ammonia-rich feedstock.

Porous Materials for Hydrolytic Dehydrogenation of Ammonia Borane

OpenAIRE

Umegaki, Tetsuo; Xu, Qiang; Kojima, Yoshiyuki

2015-01-01

Hydrogen storage is still one of the most significant issues hindering the development of a “hydrogen energy economy”. Ammonia borane is notable for its high hydrogen densities. For the material, one of the main challenges is to release efficiently the maximum amount of the stored hydrogen. Hydrolysis reaction is a promising process by which hydrogen can be easily generated from this compound. High purity hydrogen from this compound can be evolved in the presence of solid acid or metal based ...

Pharmacological experiment of 13N-ammonia as PET imaging agent

International Nuclear Information System (INIS)

Wang Mingfang; Tang Ganghua; Gao Xiao; Li Zhi; Wu Hubing; Huang Zuhan; Jiang Hong; Zhong Jinmei; Wang Quanshi

2002-01-01

Objective: To study the pharmacological characteristics of 13 N-ammonia, the clinical PET imaging methods of 13 N-ammonia, and its application in myocardial blood flow perfusion. Methods: The uptakes of 13 N-ammonia in the myocardium and other organs in dogs were measured by whole body scanning and chest dynamic PET scanning. The regional myocardial blood flow (rMBF) in healthy volunteers was also measured by the dynamic and static PET imaging following intravenous bolus administration of 13 N-ammonia. Results: The heart and lungs were the first-pass organs that was found out by PET imaging with 13 N-ammonia in dogs and human volunteers, the highest uptake of 13 N-ammonia in the myocardium was also observed. At 30 s after injection the radioactivity in the blood pool of left and right ventricles reached its peak, at 1 min it began to drop, and at 4-20 min after injection the lower radioactivity was kept on. Regional analysis of PET imaging showed that the myocardial uptake of 13 N-ammonia began at 10 s after injection, and the uptake in the septum wall was higher than that in the lateral wall; but in the septum wall was slightly higher than in the lateral wall at 2 min after injection. The radioactivity in the liver and lungs reached its peak at 30 s and was sharply declined hereafter. The uptake of 13 N-ammonia in the liver and lungs remained at the lower levels and the heart-to-blood, heart-to-liver and heart-to-lung ratios were above 2.0 after 5 min. Whole-body PET scanning for dogs showed that 13 N-ammonia was distributed primarily in the organs with rich blood flow and its clearance was observed in the kidney. The images of regional myocardial blood flow (rMBF) acquired from the dynamic or static PET imaging following intravenous bolus administration of 13 N-ammonia were of no difference. Conclusions: The analysis of distribution of 13 N-ammonia indicates that the heart-to-blood, heart-to-liver and heat-to-lung ratios were high and the PET images were clear

Accelerated in vitro release testing method for naltrexone loaded PLGA microspheres.

Science.gov (United States)

Andhariya, Janki V; Choi, Stephanie; Wang, Yan; Zou, Yuan; Burgess, Diane J; Shen, Jie

2017-03-30

The objective of the present study was to develop a discriminatory and reproducible accelerated release testing method for naltrexone loaded parenteral polymeric microspheres. The commercially available naltrexone microsphere product (Vivitrol ® ) was used as the testing formulation in the in vitro release method development, and both sample-and-separate and USP apparatus 4 methods were investigated. Following an in vitro drug stability study, frequent media replacement and addition of anti-oxidant in the release medium were used to prevent degradation of naltrexone during release testing at "real-time" (37°C) and "accelerated" (45°C), respectively. The USP apparatus 4 method was more reproducible than the sample-and-separate method. In addition, the accelerated release profile obtained using USP apparatus 4 had a shortened release duration (within seven days), and good correlation with the "real-time" release profile. Lastly, the discriminatory ability of the developed accelerated release method was assessed using compositionally equivalent naltrexone microspheres with different release characteristics. The developed accelerated USP apparatus 4 release method was able to detect differences in the release characteristics of the prepared naltrexone microspheres. Moreover, a linear correlation was observed between the "real-time" and accelerated release profiles of all the formulations investigated, suggesting that the release mechanism(s) may be similar under both conditions. These results indicate that the developed accelerated USP apparatus 4 method has the potential to be an appropriate fast quality control tool for long-acting naltrexone PLGA microspheres. Copyright © 2017 Elsevier B.V. All rights reserved.

Assessment of regional myocardial blood flow with N-13 ammonia PET

International Nuclear Information System (INIS)

Himi, Toshiharu

1992-01-01

Regional myocardial blood flow (RMBF) has been assessed with O-15 water, O-15 CO 2 and N-13 ammonia in Japan, and O-15 water has been used most commonly for quantitative measurement of RMBF with Iida's method. Though myocardial image quality with N-13 ammonia is superior to that with O-15 water or that with O-15 CO 2 , RMBF was not assessed quantitatively with N-13 ammonia. We have attempted to assess RMBF non-invasively with N-13 ammonia and dynamic PET. Yoshida et. al applied the first-pass flow model to N-13 ammonia dynamic PET for measurement of RMBF. We could measure RMBF of the patients with hypertrophic cardiomyopathy (HCM) and could assess effects of vaso-dilating agents on RMBF non-invasively with this method. But this method dose not take account of cross-contamination of recorded counts between myocardium and surrounding tissues, and hence we have applied factor analysis to dynamic PET for correction of that. It was suggested that cross-contamination in normal cases could be corrected by the factor analysis and there were few cross-contamination in the patients with HCM. (author)

Removal of ammonia nitrogen in wastewater by microwave radiation: A pilot-scale study

International Nuclear Information System (INIS)

Lin Li; Chen Jing; Xu Zuqun; Yuan Songhu; Cao Menghua; Liu Huangcheng; Lu Xiaohua

2009-01-01

A large removal of ammonia nitrogen in wastewater has been achieved by microwave (MW) radiation in our previous bench-scale study. This study developed a continuous pilot-scale MW system to remove ammonia nitrogen in real wastewater. A typical high concentration of ammonia nitrogen contaminated wastewater, the coke-plant wastewater from a Coke company, was treated. The output power of the microwave reactor was 4.8 kW and the handling capacity of the reactor was about 5 m 3 per day. The ammonia removal efficiencies under four operating conditions, including ambient temperature, wastewater flow rate, aeration conditions and initial concentration were evaluated in the pilot-scale experiments. The ammonia removal could reach about 80% for the real coke-plant wastewater with ammonia nitrogen concentrations of 2400-11000 mg/L. The running cost of the MW technique was a little lower than the conventional steam-stripping method. The continuous microwave system showed the potential as an effective method for ammonia nitrogen removal in coke-plant water treatment. It is proposed that this process is suitable for the treatment of toxic wastewater containing high concentrations of ammonia nitrogen.

Innovative bioelectrochemical-anaerobic-digestion integrated system for ammonia recovery and bioenergy production from ammonia-rich residues

DEFF Research Database (Denmark)

Zhang, Yifeng; Angelidaki, Irini

2015-01-01

(SMRC) and a continuous stirred tank reactor (CSTR), to prevent ammonia toxicity during anaerobic digestion by in-situ ammonia recovery and electricity production (Figure 1). In batch experiment, the ammonia concentration in the CSTR decreased from 6 to 0.7 g-N/L with an average recovery rate of 0.18 g-N/L(CSTR...... performance was enhanced. In addition, the coexistence of other cations in CSTR or cathode had no negative effect on the ammonia transportation. In continuous reactor operation, 112% extra biogas production was achieved due to ammonia recovery. High-throughput molecular sequencing analysis showed an impact...... of ammonia recovery on the microbial community composition in the integrated system. Results clearly indicate the great potential of the SMRC-CSTR-coupled system for efficient and cost-effective ammonia recovery, energy production and treatment of ammonia-rich residues....

Preparation and Sintering Behaviour of Alumina Powder by Ammonia Precipitation Method

Directory of Open Access Journals (Sweden)

Wang Liuyan

2017-01-01

Full Text Available In this paper, alumina precursor was prepared by the ammonia precipitation method which used Al (NO3 3 9H2O as aluminum source and NH4OH as a precipitator, adding a small amount of PEG4000 as the surface active agent. Finally γ-Al2O3 was obtained at 900° for 2h. The stable alumina crystal form of α-Al2O3 was got at 1100° for 2h. The influence of precipitation agent on the precursor was studied by means of TG / DTA and Tem, XRD etc. The effects of the synthesis temperature and time on the phase composition and morphology of the alumina powder were also analysed.

Modelling of Ammonia Heat Pump Desuperheaters

DEFF Research Database (Denmark)

Christensen, Stefan Wuust; Elmegaard, Brian; Markussen, Wiebke Brix

2015-01-01

This paper presents a study of modelling desuperheating in ammonia heat pumps. Focus is on the temperature profile of the superheated refrigerant. Typically, the surface area of a heat exchanger is estimated using the Log Mean Temperature Difference (LMTD) method. The assumption of this method...... is that the specific heat is constant throughout the temperature glide of the refrigerant in the heat exchanger. However, considering ammonia as refrigerant, the LMTD method does not give accurate results due to significant variations of the specific heat. By comparing the actual temperature profiles from a one....... The area of the heat exchanger can be increased or the condensation temperature can be raised to achieve the same temperature difference for the discretized model as for the LMTD. This would affect the compressor work, hence the COP of the system. Furthermore, for higher condenser pressure, and thus higher...

RESULTS OF INITIAL AMMONIA OXIDATION TESTING

Energy Technology Data Exchange (ETDEWEB)

Nash, C. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Fowley, M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2016-12-30

This memo presents an experimental survey of aqueous phase chemical processes to remove aqueous ammonia from waste process streams. Ammonia is generated in both the current Hanford waste flowsheet and in future waste processing. Much ammonia will be generated in the Low Activity Waste (LAW) melters.i Testing with simulants in glass melters at Catholic University has demonstrated the significant ammonia production.ii The primary reaction there is the reducing action of sugar on nitrate in the melter cold cap. Ammonia has been found to be a problem in secondary waste stabilization. Ammonia vapors are noxious and destruction of ammonia could reduce hazards to waste treatment process personnel. It is easily evolved especially when ammonia-bearing solutions are adjusted to high pH.

Ammonia, hydrogen sulfide, carbon dioxide and particulate matter emissions from California high-rise layer houses

Science.gov (United States)

Lin, X.-J.; Cortus, E. L.; Zhang, R.; Jiang, S.; Heber, A. J.

2012-01-01

Ammonia and hydrogen sulfide are hazardous substances that are regulated by the U.S. Environmental Protection Agency through community right-to-know legislation (EPCRA, EPA, 2011). The emissions of ammonia and hydrogen sulfide from large commercial layer facilities are of concern to legislators and nearby neighbors. Particulate matter (PM 10 and PM 2.5) released from layer houses are two of seven criteria pollutants for which EPA has set National Ambient Air Quality Standards as required by the Clean Air Act. Therefore, it is important to quantify the baseline emissions of these pollutants. The emissions of ammonia, hydrogen sulfide, carbon dioxide and PM from two California high-rise layer houses were monitored for two years from October 2007 to October 2009. Each house had 32,500 caged laying hens. The monitoring site was setup in compliance with a U.S. EPA-approved quality assurance project plan. The results showed the average daily mean emission rates of ammonia, hydrogen sulfide and carbon dioxide were 0.95 ± 0.67 (standard deviation) g d -1 bird -1, 1.27 ± 0.78 mg d -1 bird -1 and 91.4 ± 16.5 g d -1 bird -1, respectively. The average daily mean emission rates of PM 2.5, PM 10 and total suspended particulate (TSP) were 5.9 ± 12.6, 33.4 ± 27.4, and 78.0 ± 42.7 mg d -1 bird -1, respectively. It was observed that ammonia emission rates in summer were lower than in winter because the high airflow stabilized the manure by drying it. The reductions due to lower moisture content were greater than the increases due to higher temperature. However, PM 10 emission rates in summer were higher than in winter because the drier conditions coupled with higher internal air velocities increased PM 10 release from feathers, feed and manure.

Clinical utility of breath ammonia for evaluation of ammonia physiology in healthy and cirrhotic adults

OpenAIRE

Spacek, Lisa A; Mudalel, Matthew; Tittel, Frank; Risby, Terence H; Solga, Steven F

2015-01-01

Blood ammonia is routinely used in clinical settings to assess systemic ammonia in hepatic encephalopathy and urea cycle disorders. Despite its drawbacks, blood measurement is often used as a comparator in breath studies because it is a standard clinical test. We sought to evaluate sources of measurement error and potential clinical utility of breath ammonia compared to blood ammonia.

Recycling of Ammonia Wastewater During Vanadium Extraction from Shale

Science.gov (United States)

Shi, Qihua; Zhang, Yimin; Liu, Tao; Huang, Jing

2018-03-01

In the vanadium metallurgical industry, massive amounts of ammonia hydroxide or ammonia salt are added during the precipitation process to obtain V2O5; therefore, wastewater containing a high level of NH4 + is generated, which poses a serious threat to environmental and hydrologic safety. In this article, a novel process was developed to recycle ammonia wastewater based on a combination of ammonia wastewater leaching and crystallization during vanadium extraction from shale. The effects of the NH4 + concentration, temperature, time and liquid-to-solid ratio on the leaching efficiencies of vanadium, aluminum and potassium were investigated, and the results showed that 93.2% of vanadium, 86.3% of aluminum and 96.8% of potassium can be leached from sulfation-roasted shale. Subsequently, 80.6% of NH4 + was separated from the leaching solution via cooling crystallization. Vanadium was recovered via a combined method of solvent extraction, precipitation and calcination. Therefore, ammonia wastewater was successfully recycled during vanadium extraction from shale.

Transcriptional Response of the Archaeal Ammonia Oxidizer Nitrosopumilus maritimus to Low and Environmentally Relevant Ammonia Concentrations

OpenAIRE

Nakagawa, Tatsunori; Stahl, David A.

2013-01-01

The ability of chemoautotrophic ammonia-oxidizing archaea to compete for ammonia among marine microorganisms at low ambient concentrations has been in part attributed to their extremely high affinity for ammonia, but as yet there is no mechanistic understanding of supporting metabolism. We examined transcription of selected genes for anabolic functions (CO2 fixation, ammonia transport, and cell wall synthesis) and a central catabolic function (ammonia oxidation) in the thaumarchaeon Nitrosopu...

Regeneration of ammonia borane from spent fuel materials.

Science.gov (United States)

Summerscales, Owen T; Gordon, John C

2013-07-28

A shift to the hydrogen economy requires the development of an effective hydrogen fuel carrier with high volumetric and gravimetric storage capacity. Ammonia borane (AB) has emerged as a leading candidate due to its light weight and multiple protic (N-H) and hydridic (B-H) hydrogens. As a consequence, much work has been directed towards fine tuning the release of H2 from AB, in addition to its regeneration from the dehydrogenated "spent fuel" materials. This review summarizes the development of these regeneration methodologies.

Renal Ammonia Metabolism and Transport

Science.gov (United States)

Weiner, I. David; Verlander, Jill W.

2015-01-01

Renal ammonia metabolism and transport mediates a central role in acid-base homeostasis. In contrast to most renal solutes, the majority of renal ammonia excretion derives from intrarenal production, not from glomerular filtration. Renal ammoniagenesis predominantly results from glutamine metabolism, which produces 2 NH4+ and 2 HCO3− for each glutamine metabolized. The proximal tubule is the primary site for ammoniagenesis, but there is evidence for ammoniagenesis by most renal epithelial cells. Ammonia produced in the kidney is either excreted into the urine or returned to the systemic circulation through the renal veins. Ammonia excreted in the urine promotes acid excretion; ammonia returned to the systemic circulation is metabolized in the liver in a HCO3−-consuming process, resulting in no net benefit to acid-base homeostasis. Highly regulated ammonia transport by renal epithelial cells determines the proportion of ammonia excreted in the urine versus returned to the systemic circulation. The traditional paradigm of ammonia transport involving passive NH3 diffusion, protonation in the lumen and NH4+ trapping due to an inability to cross plasma membranes is being replaced by the recognition of limited plasma membrane NH3 permeability in combination with the presence of specific NH3-transporting and NH4+-transporting proteins in specific renal epithelial cells. Ammonia production and transport are regulated by a variety of factors, including extracellular pH and K+, and by several hormones, such as mineralocorticoids, glucocorticoids and angiotensin II. This coordinated process of regulated ammonia production and transport is critical for the effective maintenance of acid-base homeostasis. PMID:23720285

Nitrogen removal from digested slurries using a simplified ammonia stripping technique.

Science.gov (United States)

Provolo, Giorgio; Perazzolo, Francesca; Mattachini, Gabriele; Finzi, Alberto; Naldi, Ezio; Riva, Elisabetta

2017-11-01

This study assessed a novel technique for removing nitrogen from digested organic waste based on a slow release of ammonia that was promoted by continuous mixing of the digestate and delivering a continuous air stream across the surface of the liquid. Three 10-day experiments were conducted using two 50-L reactors. In the first two, nitrogen removal efficiencies were evaluated from identical digestates maintained at different temperatures (30°C and 40°C). At the start of the first experiment, the digestates were adjusted to pH 9 using sodium hydroxide, while in the second experiment pH was not adjusted. The highest ammonia removal efficiency (87%) was obtained at 40°C with pH adjustment. However at 40°C without pH adjustment, removal efficiencies of 69% for ammonia and 47% for total nitrogen were obtained. In the third experiment two different digestates were tested at 50°C without pH adjustment. Although the initial chemical characteristics of the digestates were different in this experiment, the ammonia removal efficiencies were very similar (approximately 85%). Despite ammonia removal, the pH increased in all experiments, most likely due to carbon dioxide stripping that was promoted by temperature and mixing. The technique proved to be suitable for removing nitrogen following anaerobic digestion of livestock manure because effective removal was obtained at natural pH (≈8) and 40°C, common operating conditions at typical biogas plants that process manure. Furthermore, the electrical energy requirement to operate the process is limited (estimated to be 3.8kWhm -3 digestate). Further improvements may increase the efficiency and reduce the processing time of this treatment technique. Even without these advances slow-rate air stripping of ammonia is a viable option for reducing the environmental impact associated with animal manure management. Copyright © 2017 Elsevier Ltd. All rights reserved.

IRIS Assessment Plan for Ammonia and Ammonium Salts Noncancer Oral (Scoping and Problem Formulation Materials)

Science.gov (United States)

In April 2018, EPA released the draft IRIS Assessment Plan for Ammonia and Ammonium Salts Noncancer Oral. The IAP communicates to the public the plan for assessing each individual chemical and includes summary information on the IRIS Program’s scoping and initial proble...

IRIS Assessment Plan for Ammonia and Ammonium Salts Noncancer Oral (Scoping and Problem Formulation Materials)

Science.gov (United States)

In April 2018, EPA released the draft IRIS Assessment Plan for Ammonia and Ammonium Salts Noncancer Oral. An IRIS Assessment Plan (IAP) communicates to the public the plan for assessing each individual chemical and includes summary information on the IRIS Program’s sco...

Ammonia treated Mo/AC catalysts for CO hydrogenation with ...

Indian Academy of Sciences (India)

A series of ammonia treated Mo/Activated Carbon (AC) catalysts were synthesized by wet impregnation method by nominal incorporation of 5, 10 and 15 wt% of molybdenum. The calcined catalysts (500◦C, 4 h, N₂ flow) were subjected to a stepwise ammonia treatment at temperatures from 25 up to 700◦C. This work ...

Dynamics of nitrification and denitrification in root- oxygenated sediments and adaptation of ammonia-oxidizing bacteria to low-oxygen or anoxic habitats

NARCIS (Netherlands)

Bodelier, P.L.E.; Libochant, J.A.; Blom, C.W.P.M.; Laanbroek, H.J.

1996-01-01

Oxygen-releasing plants may provide aerobic niches in anoxic sediments and soils for ammonia-oxidizing bacteria, The oxygen- releasing, aerenchymatous emergent macrophyte Glycerin maxima had a strong positive effect on numbers and activities of the nitrifying bacteria in its root zone in spring and

Dynamics of nitrification and denitrification in root- oxygenated sediments and adaptation of ammonia-oxidizing bacteria to low-oxygen or anoxic habitats

NARCIS (Netherlands)

Bodelier, P.L.E.; Libochant, J.A.; Blom, C.W.P.M.; Laanbroek, H.J.

1996-01-01

Oxygen-releasing plants may provide aerobic niches in anoxic sediments and soils for ammonia-oxidizing bacteria. The oxygen-releasing, aerenchymatous emergent macrophyte Glyceria maxima had a strong positive effect on numbers and activities of the nitrifying bacteria in its root zone in spring and

Ammonia toxicity: from head to toe?

Science.gov (United States)

Dasarathy, Srinivasan; Mookerjee, Rajeshwar P; Rackayova, Veronika; Rangroo Thrane, Vinita; Vairappan, Balasubramaniyan; Ott, Peter; Rose, Christopher F

2017-04-01

Ammonia is diffused and transported across all plasma membranes. This entails that hyperammonemia leads to an increase in ammonia in all organs and tissues. It is known that the toxic ramifications of ammonia primarily touch the brain and cause neurological impairment. However, the deleterious effects of ammonia are not specific to the brain, as the direct effect of increased ammonia (change in pH, membrane potential, metabolism) can occur in any type of cell. Therefore, in the setting of chronic liver disease where multi-organ dysfunction is common, the role of ammonia, only as neurotoxin, is challenged. This review provides insights and evidence that increased ammonia can disturb many organ and cell types and hence lead to dysfunction.

Determination of Ammonia in Household Cleaners: An Instrumental Analysis Experiment.

Science.gov (United States)

Graham, Richard C.; DePew, Steven

1983-01-01

Briefly discusses three techniques for assessing amount of ammonia present in household cleaners. Because of disadvantages with these methods, the thermometric titration technique is suggested in which students judge the best buy based on relative cost of ammonia present in samples. Laboratory procedures, typical results, and reactions involved…

Measuring ammonia concentrations and emissions from agricultural land and liquid surfaces: a review.

Science.gov (United States)

Shah, Sanjay B; Westerman, Philip W; Arogo, Jactone

2006-07-01

Aerial ammonia concentrations (Cg) are measured using acid scrubbers, filter packs, denuders, or optical methods. Using Cg and wind speed or airflow rate, ammonia emission rate or flux can be directly estimated using enclosures or micrometeorological methods. Using nitrogen (N) recovery is not recommended, mainly because the different gaseous N components cannot be separated. Although low cost and replicable, chambers modify environmental conditions and are suitable only for comparing treatments. Wind tunnels do not modify environmental conditions as much as chambers, but they may not be appropriate for determining ammonia fluxes; however, they can be used to compare emissions and test models. Larger wind tunnels that also simulate natural wind profiles may be more useful for comparing treatments than micrometeorological methods because the latter require larger plots and are, thus, difficult to replicate. For determining absolute ammonia flux, the micrometeorological methods are the most suitable because they are nonintrusive. For use with micrometeorological methods, both the passive denuders and optical methods give comparable accuracies, although the latter give real-time Cg but at a higher cost. The passive denuder is wind weighted and also costs less than forced-air Cg measurement methods, but it requires calibration. When ammonia contamination during sample preparation and handling is a concern and separating the gas-phase ammonia and aerosol ammonium is not required, the scrubber is preferred over the passive denuder. The photothermal interferometer, because of its low detection limit and robustness, may hold potential for use in agriculture, but it requires evaluation. With its simpler theoretical basis and fewer restrictions, the integrated horizontal flux (IHF) method is preferable over other micrometeorological methods, particularly for lagoons, where berms and land-lagoon boundaries modify wind flow and flux gradients. With uniform wind flow, the ZINST

Continuous determination of gaseous ammonia in the ambient atmosphere using fluorescence derivatization

Science.gov (United States)

Abbas, Rana; Tanner, Roger L.

A method for continuous determination of ambient ammonia levels employing o-phthalaldehyde fluorescence derivatization is described. A simplified Venturi scrubber and gas-liquid separator have been employed for reproducible measurements of ⩾ 0.1 ppb ambient ammonia with less than 2 min time resolution. The scrubbing efficiency of the ammonia gas collection system was determined to be 29 ± 1 %. During 4 d in August 1979 ambient ammonia levels at the Brookhaven National Laboratory site averaged about 1.5 ± 1.1 ppb during afternoon daylight hours.

Abiotic nitrogen fixation on terrestrial planets: reduction of NO to ammonia by FeS.

Science.gov (United States)

Summers, David P; Basa, Ranor C B; Khare, Bishun; Rodoni, David

2012-02-01

Understanding the abiotic fixation of nitrogen and how such fixation can be a supply of prebiotic nitrogen is critical for understanding both the planetary evolution of, and the potential origin of life on, terrestrial planets. As nitrogen is a biochemically essential element, sources of biochemically accessible nitrogen, especially reduced nitrogen, are critical to prebiotic chemistry and the origin of life. Loss of atmospheric nitrogen can result in loss of the ability to sustain liquid water on a planetary surface, which would impact planetary habitability and hydrological processes that shape the surface. It is known that NO can be photochemically converted through a chain of reactions to form nitrate and nitrite, which can be subsequently reduced to ammonia. Here, we show that NO can also be directly reduced, by FeS, to ammonia. In addition to removing nitrogen from the atmosphere, this reaction is particularly important as a source of reduced nitrogen on an early terrestrial planet. By converting NO directly to ammonia in a single step, ammonia is formed with a higher product yield (~50%) than would be possible through the formation of nitrate/nitrite and subsequent conversion to ammonia. In conjunction with the reduction of NO, there is also a catalytic disproportionation at the mineral surface that converts NO to NO₂ and N₂O. The NO₂ is then converted to ammonia, while the N₂O is released back in the gas phase, which provides an abiotic source of nitrous oxide.

Ammonia Leak Locator Study

Science.gov (United States)

Dodge, Franklin T.; Wuest, Martin P.; Deffenbaugh, Danny M.

1995-01-01

The thermal control system of International Space Station Alpha will use liquid ammonia as the heat exchange fluid. It is expected that small leaks (of the order perhaps of one pound of ammonia per day) may develop in the lines transporting the ammonia to the various facilities as well as in the heat exchange equipment. Such leaks must be detected and located before the supply of ammonia becomes critically low. For that reason, NASA-JSC has a program underway to evaluate instruments that can detect and locate ultra-small concentrations of ammonia in a high vacuum environment. To be useful, the instrument must be portable and small enough that an astronaut can easily handle it during extravehicular activity. An additional complication in the design of the instrument is that the environment immediately surrounding ISSA will contain small concentrations of many other gases from venting of onboard experiments as well as from other kinds of leaks. These other vapors include water, cabin air, CO2, CO, argon, N2, and ethylene glycol. Altogether, this local environment might have a pressure of the order of 10(exp -7) to 10(exp -6) torr. Southwest Research Institute (SwRI) was contracted by NASA-JSC to provide support to NASA-JSC and its prime contractors in evaluating ammonia-location instruments and to make a preliminary trade study of the advantages and limitations of potential instruments. The present effort builds upon an earlier SwRI study to evaluate ammonia leak detection instruments [Jolly and Deffenbaugh]. The objectives of the present effort include: (1) Estimate the characteristics of representative ammonia leaks; (2) Evaluate the baseline instrument in the light of the estimated ammonia leak characteristics; (3) Propose alternative instrument concepts; and (4) Conduct a trade study of the proposed alternative concepts and recommend promising instruments. The baseline leak-location instrument selected by NASA-JSC was an ion gauge.

Basic Physical Properties of Ammonia-Rich Ice

Science.gov (United States)

Shandera, S. E.; Lorenz, R. D.

2000-10-01

We report simple measurements of the thermal conductivity, mechanical strength and microwave absorptivity of ammonia hydrate ices, which are likely to be abundant in the Saturnian system. Understanding the dielectric properties of ammonia ice could play an important role in interpreting data from the Cassini spacecraft, which will image Titan's surface by radar in 2004. Thermal conductivity measurements were made by freezing a thin copper wire in the center of ice samples. The wire acted as both heater and temperature sensor, calibrated by a thermocouple also frozen in the sample. Ices with concentrations of 5- 30% ammonia were compared to pure water ice and ices containing salts. Thermal conductivity was found to decrease with increasing concentration of ammonia - a factor of 3 or 4 less than pure water ice for the 30% peritectic composition. Microwave absorptivity was measured by placing insulated ice samples and calibration materials in a conventional microwave oven. The microwave absorptivity was found to increase with increasing concentration of ammonia, although the effect is strongly temperature dependent, and heat leak from the room made quantitative measurement difficult. Mechanical strength was estimated using a ball bearing/accelerometer indentation method. For temperatures 100-150K, ammonia-rich ice has a Young's modulus about 10x smaller than pure ice. These properties affect tidal dissipation and the likelihood and style of cryovolcanism on (and the radar appearance of) the icy satellites and Titan. This work was supported by the Cassini RADAR team and the Arizona Space Grant Consortium.

Rectal administration of 13N-ammonia in the study of ammonia metabolism

International Nuclear Information System (INIS)

Koen, Hirofumi

1980-01-01

13 N-ammonia produced by the cyclotron was instilled intrarectally in patients with liver diseases for the study of the turnover of rectally absorbed 13 N-ammonia. A positron camera connected to an on-line computer system was used for imaging of the liver and heart; 13 N-activity over the head was also recorded. Sequential changes of 13 N-activity in blood was measured, and chromatographic analysis of 13 N-labeled substances in blood was carried out using a Dowex 50W x 8 column. In the control, 13 N-ammonia was absorbed quickly into blood visualizing the liver shortly after administration, and hepatic uptake of 13 N-ammonia reached a plateau in 10 -- 15 min, whereas in patients with cirrhosis, the lung and heart were visualized in 5 min when the liver image was still faint. 13 N-activity over the head was apparently higher in the cirrhotic group. It was suggested that a large proportion of absorbed 13 N-ammonia bypassed liver cells and reached peripheral tissues. The heart/liver ratio of 13 N and 13 N over the head were closely correlated with various indices of portal hypertension. The relative proportion of 13 N-metabolites in blood was lower at 5 min and 15 min after administration in cirrhosis, suggesting a reduced capacity of the liver to remove and metabolize ammonia. (author)

Ammonia Emissions from Agriculture in China

Science.gov (United States)

Chen, Y.; Zhang, L.; Zhao, Y.; Huang, B.

2016-12-01

Ammonia (NH3) is an important alkaline pollutant in the atmosphere and it has various environmental and climatic effects. We will present an improved bottom-up estimate of ammonia emissions from agriculture in China at 0.5°×0.5° horizontal resolution and monthly variability. Ammonia emissions from fertilizer use are derived using data of crop planting area, fertilizer application time and rate for 18 main crops. Ammonia emission factors from fertilizer use are estimated as a function of soil properties such as soil pH, cation exchange capacity (CEC), and agricultural activity information such as crop type, fertilizer type, and application mode. We further consider ambient temperature and wind speed to account for the meteorological influences on ammonia emission factors of fertilizer use. We also estimate the ammonia emission from livestock over China using the mass-flow methodology. The derived ammonia emissions in China for the year 2005 are 4.55 Tg NH3 from fertilizer use and 6.96 Tg from livestock. Henan and Jiangsu provinces are the two largest emitting areas for ammonia from fertilizer use (470 Gg NH3 and 365 Gg NH3). Henan (621 Gg NH3) and Shandong (533 Gg NH3) have the largest ammonia emissions from livestock. Both ammonia emissions from fertilizer use and livestock have distinct seasonal variations; peaking in June for fertilizer use (822 Gg NH3) and in July for livestock (1244 Gg NH3), and are both lowest in January (80 Gg and 241 Gg, respectively). Combining with other ammonia source (eg. human waste and transport) estimates from the REAS v2.1 emission inventory, we show that total ammonia emissions in China for the year 2005 are 14.0 Tg NH3 a-1. Comparisons with satellite measurements of ammonia columns will also be presented.

Kinetics of the ammonia synthesis at low temperatures. II. Sources of discrepancies

International Nuclear Information System (INIS)

Kuchaev, V.L.; Shapatina, E.N.; Temkin, M.I.

1988-01-01

A method is developed for calculating the degree of conversion during the synthesis of ammonia in a continuous flow, tubular reactor, taking longitudinal diffusion into account. Such a calculation shows that the available data in the literature on the rate of ammonia synthesis at low temperatures in a tubular reactor agree with the rate equation based on the idea that the predominant intermediate substance is adsorbed ammonia (and not imide). The seeming conflict between this idea and the ratio of the rates of synthesis of ammonia and deuteroammonia at low temperatures is explained

Final Report UCLA-Thermochemical Storage with Anhydrous Ammonia

Energy Technology Data Exchange (ETDEWEB)

Lavine, Adrienne [Univ. of California, Los Angeles, CA (United States)

2018-02-05

In ammonia-based thermochemical energy storage (TCES), ammonia is dissociated endothermically as it absorbs solar energy during the daytime. When energy is required, the reverse reaction releases energy to heat a working fluid such as steam, to produce electricity. Ammonia-based TCES has great advantages of simplicity, low cost reactants, and a strong industrial base in the conventional ammonia industry. The concept has been demonstrated over three decades of research at Australian National University, achieving a 24-hour demonstration of a complete system. At the start of this project, three challenges were identified that would have to be addressed to show that the system is technically and economically viable for incorporation into a CSP plant with an advanced, high temperature power block. All three of these challenges have now been addressed: 1. The ammonia synthesis reaction had not, to our knowledge, been carried out at temperatures consistent with modern power blocks (i.e., ~650°C). The technical feasibility of operating a reactor under high-temperature, near-equilibrium conditions was an unknown, and was therefore a technical risk. The project has successfully demonstrated steam heating to 650°C and energy recovery to steam at the 5 kWt level. 2. The ammonia system has a relatively low enthalpy of reaction combined with gas phase reactants. This is not a direct disadvantage since the reactants themselves are low cost. The challenge lies in storing the required volume of reactants cost effectively. Therefore, a second key goal was to show, through techno-economic analysis, that underground storage technologies can be used to store the energy-rich gas at a cost that is consistent with the SunShot cost goal. We have identified two promising technologies for gas storage: storage in salt caverns has an estimated cost of 1(USD)/kWht and storage in drilled shafts could be on the order of 7(USD)/kWht. Together these two options answer the technical challenge

Defences against ammonia toxicity in tropical air-breathing fishes exposed to high concentrations of environmental ammonia: a review.

Science.gov (United States)

Ip, Y K; Chew, S F; Wilson, J M; Randall, D J

2004-10-01

In the tropics, air-breathing fishes can be exposed to environmental ammonia when stranded in puddles of water during the dry season, during a stay inside a burrow, or after agricultural fertilization. At low concentrations of environmental ammonia, NH(3) excretion is impeded, as in aerial exposure, leading to the accumulation of endogenous ammonia. At high concentrations of environmental ammonia, which results in a reversed NH(3) partial pressure gradient (DeltaP(NH3)), there is retention of endogenous ammonia and uptake of exogenous ammonia. In this review, several tropical air-breathing fishes (giant mudskipper, African catfish, oriental weatherloach, swamp eel, four-eyed sleeper, abehaze and slender African lungfish), which can tolerate high environmental ammonia exposure, are used as examples to demonstrate how eight different adaptations can be involved in defence against ammonia toxicity. Four of these adaptations deal with ammonia toxicity at branchial and/or epithelial surfaces: (1) active excretion of NH(4)(+); (2) lowering of environmental pH; (3) low NH(3) permeability of epithelial surfaces; and (4) volatilization of NH(3), while another four adaptations ameliorate ammonia toxicity at the cellular and subcellular levels: (5) high tolerance of ammonia at the cellular and subcellular levels; (6) reduction in ammonia production; (7) glutamine synthesis; and (8) urea synthesis. The responses of tropical air-breathing fishes to high environmental ammonia are determined apparently by behavioural adaptations and the nature of their natural environments.

Ammonia and ammonium over the southern Baltic Sea. Part 1. Preparation of aerosol and air samples for the determination of ammonia by the indophenol method

Directory of Open Access Journals (Sweden)

Lucyna Falkowska

2004-06-01

Full Text Available 1997 saw the start of a study into the spatial and temporal changes in the chemical composition of the atmosphere over the littoral and offshore waters of the Baltic Sea. Collection of samples and their subsequent chemical analysis was preceded by meticulous laboratory experiments concerning the validation and adaptation of the analytical procedures. The colorimetric indophenol blue technique was used to analyse the aerosol samples for the concentration of ammonium ions and the air samples for their gaseous ammonia. The samples were collected with PTFE-filters and Whatman 41 filters coated with 5% orthophosphoric acid. This acid enhances the aerosol sampling efficacy but reduces the pH of the reaction in which indophenol is formed. The pH of the aerosol samples thus had to be raised, and this in turn required an alteration to the original procedure prior to ammonia determination. It was demonstrated that the addition of 0.1 N KOH to the filters coated with H3PO4 increases the pH of the reaction medium to the required level of pH = 8-11.5 and does not substantially influence the precision of the determination; the error of the modified procedure was of the order of 5.2%.      Air samples for the determination of gaseous ammonia were collected with annular denuders. Oxalic acid and citric acid are the usual impregnating agents. In the present experiments oxalic acid was used for denuder impregnation; it turned out to be more effective than citric acid under the conditions of the southern Baltic Sea.      The detection limit of the indophenol blue method in these laboratory experiments was 0.045 mmol dm-3. The respective relative standard deviations (RSD within the range of higher and lower concentrations were 0.64% and 4.53%.

Directional passive ambient air monitoring of ammonia for fugitive source attribution; a field trial with wind tunnel characteristics

Science.gov (United States)

Solera García, M. A.; Timmis, R. J.; Van Dijk, N.; Whyatt, J. D.; Leith, I. D.; Leeson, S. R.; Braban, C. F.; Sheppard, L. J.; Sutton, M. A.; Tang, Y. S.

2017-10-01

Atmospheric ammonia is a precursor for secondary particulate matter formation, which harms human health and contributes to acidification and eutrophication. Under the 2012 Gothenburg Protocol, 2005 emissions must be cut by 6% by 2020. In the UK, 83% of total emissions originate from agricultural practices such as fertilizer use and rearing of livestock, with emissions that are spatially extensive and variable in nature. Such fugitive emissions make resolving and tracking of individual site performance challenging. The Directional Passive Air quality Sampler (DPAS) was trialled at Whim Bog, an experimental site with a wind-controlled artificial release of ammonia, in combination with CEH-developed ammonia samplers. Whilst saturation issues were identified, two DPAS-MANDE (Mini Annular Denuder) systems, when deployed in parallel, displayed an average relative deviation of 15% (2-54%) across all 12 directions, with the directions exposed to the ammonia source showing ∼5% difference. The DPAS-MANDE has shown great potential for directional discrimination and can contribute to the understanding and management of fugitive ammonia sources from intensive agriculture sites.

Carbon-dependent alleviation of ammonia toxicity for algae cultivation and associated mechanisms exploration.

Science.gov (United States)

Lu, Qian; Chen, Paul; Addy, Min; Zhang, Renchuan; Deng, Xiangyuan; Ma, Yiwei; Cheng, Yanling; Hussain, Fida; Chen, Chi; Liu, Yuhuan; Ruan, Roger

2018-02-01

Ammonia toxicity in wastewater is one of the factors that limit the application of algae technology in wastewater treatment. This work explored the correlation between carbon sources and ammonia assimilation and applied a glucose-assisted nitrogen starvation method to alleviate ammonia toxicity. In this study, ammonia toxicity to Chlorella sp. was observed when NH 3 -N concentration reached 28.03mM in artificial wastewater. Addition of alpha-ketoglutarate in wastewater promoted ammonia assimilation, but low utilization efficiency and high cost of alpha-ketoglutarate limits its application in wastewater treatment. Comparison of three common carbon sources, glucose, citric acid, and sodium bicarbonate, indicates that in terms of ammonia assimilation, glucose is the best carbon source. Experimental results suggest that organic carbon with good ability of generating energy and hydride donor may be critical to ammonia assimilation. Nitrogen starvation treatment assisted by glucose increased ammonia removal efficiencies and algal viabilities. Copyright © 2017 Elsevier Ltd. All rights reserved.

A fast and effective method for N-doping TiO2 by post treatment with liquid ammonia: visible light photocatalysis

International Nuclear Information System (INIS)

Powell, Michael J.; Palgrave, Robert G.; Dunnill, Charles W.; Parkin, Ivan P.

2014-01-01

TiO 2 thin films prepared by sol–gel synthesis were N-doped by post treating with liquid ammonia and annealing at 500 °C. Characterisation by X-ray diffraction and Raman spectroscopy confirmed that the anatase crystal type was retained and present in all samples. Scanning electron microscopy showed that treatment with liquid ammonia had no significant effect on the film morphology. Functional testing under filtered while light conditions involving water contact angle, and the photo destruction of both Resazurin and Stearic acid showed the ammonia treated samples to be active visible light photocatalysts in contrast to the pure TiO 2 and the blank controls. X-ray Photoelectron Spectroscopy studies indicate the presence of interstitial nitrogen (N 1s = 400 eV) suggesting that the origin of the enhanced photocatalytic activity is most likely due to oxygen vacancies created by the interstitial nitrogen incorporation. This synthesis method utilises a simple, inexpensive and highly effective post treatment route to N-dope TiO 2 and produces visible light photocatalysts with potential applications in self-cleaning and healthcare environments. - Highlights: • Synthesis and characterisation of N-doped TiO 2 thin films • N-doping by a post treatment with liquid ammonia • Enhanced photocatalytic activity • Easy enhancement of current TiO 2 based technologies

An engineered pathway for glyoxylate metabolism in tobacco plants aimed to avoid the release of ammonia in photorespiration

Directory of Open Access Journals (Sweden)

Carvalho Josirley de FC

2011-11-01

Full Text Available Abstract Background The photorespiratory nitrogen cycle in C3 plants involves an extensive diversion of carbon and nitrogen away from the direct pathways of assimilation. The liberated ammonia is re-assimilated, but up to 25% of the carbon may be released into the atmosphere as CO2. Because of the loss of CO2 and high energy costs, there has been considerable interest in attempts to decrease the flux through the cycle in C3 plants. Transgenic tobacco plants were generated that contained the genes gcl and hyi from E. coli encoding glyoxylate carboligase (EC 4.1.1.47 and hydroxypyruvate isomerase (EC 5.3.1.22 respectively, targeted to the peroxisomes. It was presumed that the two enzymes could work together and compete with the aminotransferases that convert glyoxylate to glycine, thus avoiding ammonia production in the photorespiratory nitrogen cycle. Results When grown in ambient air, but not in elevated CO2, the transgenic tobacco lines had a distinctive phenotype of necrotic lesions on the leaves. Three of the six lines chosen for a detailed study contained single copies of the gcl gene, two contained single copies of both the gcl and hyi genes and one line contained multiple copies of both gcl and hyi genes. The gcl protein was detected in the five transgenic lines containing single copies of the gcl gene but hyi protein was not detected in any of the transgenic lines. The content of soluble amino acids including glycine and serine, was generally increased in the transgenic lines growing in air, when compared to the wild type. The content of soluble sugars, glucose, fructose and sucrose in the shoot was decreased in transgenic lines growing in air, consistent with decreased carbon assimilation. Conclusions Tobacco plants have been generated that produce bacterial glyoxylate carboligase but not hydroxypyruvate isomerase. The transgenic plants exhibit a stress response when exposed to air, suggesting that some glyoxylate is diverted away from

21 CFR 862.1065 - Ammonia test system.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ammonia test system. 862.1065 Section 862.1065....1065 Ammonia test system. (a) Identification. An ammonia test system is a device intended to measure ammonia levels in blood, serum, and plasma, Ammonia measurements are used in the diagnosis and treatment...

ThermoEnergy Ammonia Recovery Process for Municipal and Agricultural Wastes

Directory of Open Access Journals (Sweden)

Alex G. Fassbender

2001-01-01

Full Text Available The Ammonia Recovery Process (ARP is an award-winning, low-cost, environmentally responsible method of recovering nitrogen, in the form of ammonia, from various dilute waste streams and converting it into concentrated ammonium sulfate. The ThermoEnergy Biogas System utilizes the new chemisorption-based ARP to recover ammonia from anaerobically digested wastes. The process provides for optimal biogas production and significantly reduced nitrogen levels in the treated water discharge. Process flows for the ammonia recovery and ThermoEnergy biogas processes are presented and discussed. A comparison with other techniques such as biological nitrogen removal is made. The ARP technology uses reversible chemisorption and double salt crystal precipitation to recover and concentrate the ammonia. The ARP technology was successfully proven in a recent large-scale field demonstration at New York City’s Oakwood Beach Wastewater Treatment Plant, located on Staten Island. This project was a joint effort with Foster Wheeler Environmental Corporation, the Civil Engineering Research Foundation, and New York City Department of Environmental Protection. Independent validated plant data show that ARP consistently recovers up to 99.9% of the ammonia from the city’s centrate waste stream (derived from dewatering of sewage sludge, as ammonium sulfate. ARP technology can reduce the nitrogen (ammonia discharged daily into local bodies of water by municipalities, concentrated animal farming operations, and industry. Recent advances to ARP enhance its performance and economic competitiveness in comparison to stripping or ammonia destruction technologies.

Electrolytic synthesis of ammonia in molten salts under atmospheric pressure.

Science.gov (United States)

Murakami, Tsuyoshi; Nishikiori, Tokujiro; Nohira, Toshiyuki; Ito, Yasuhiko

2003-01-15

Ammonia was successfully synthesized by using a new electrochemical reaction with high current efficiency at atmospheric pressure and at lower temperatures than the Haber-Bosch process. In this method, nitride ion (N3-), which is produced by the reduction from nitrogen gas at the cathode, is anodically oxidized and reacts with hydrogen to produce ammonia at the anode.

Ammonia threshold for inhibition of anaerobic digestion of thin stillage and the importance of organic loading rate.

Science.gov (United States)

Moestedt, Jan; Müller, Bettina; Westerholm, Maria; Schnürer, Anna

2016-03-01

Biogas production from nitrogen-rich feedstock results in release of ammonia (NH3), causing inhibition of the microbial process. The reported threshold ammonia value for stable biogas production varies greatly between studies, probably because of differences in operating conditions. Moreover, it is often difficult to separate the effect of ammonia inhibition from that of organic loading rate (OLR), as these two factors are often interrelated. This study attempted to distinguish the effects of ammonia and OLR by analysis of two laboratory-scale biogas reactors operating with thin stillage and subjected to an increase in free ammonia (from 0.30 to 1.1 g L(-1)) either by addition of an external nitrogen source (urea) or by increasing the OLR (3.2-6.0 g volatile solids L(-1) d(-1)). The results showed that ammonia concentration was detrimental for process performance, with the threshold for stability in both processes identified as being about 1 g NH3-N L(-1), irrespective of OLR. Analysis of the methanogenic community showed limited differences between the two reactors on order level and a clear increase in the abundance of Methanomicrobiales, particularly Methanoculleus sp., in response to increasing ammonia concentration. Further comprehensive molecular analysis revealed that diverse Methanoculleus species dominated in the reactors at a given ammonia level at different OLR. The acetogenic community was clearly affected by both ammonia concentration and OLR, suggesting that the volatile fatty acid load in relation to the higher OLR was important for the dynamics of this community. © 2015 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

Aquatic Life Criteria - Ammonia

Science.gov (United States)

Documents related to EPA's final 2013 Aquatic Life Ambient Water Quality Criteria for Ammonia (Freshwater). These documents pertain to the safe levels of Ammonia in water that should protect to the majority of species.

Computational Search for Improved Ammonia Storage Materials

DEFF Research Database (Denmark)

Jensen, Peter Bjerre; Lysgaard, Steen; Vegge, Tejs

Metal halide ammines, e.g. Mg(NH3)6Cl2 and Sr(NH3)8Cl2, can reversibly store ammonia, with high volumetric hydrogen storage capacities. The storage in the halide ammines is very safe, and the salts are therefore highly relevant as a carbon-free energy carrier in future transportation infrastructure...... selection. The GA is evolving from an initial (random) population and selecting those with highest fitness, a function based on e.g. stability, release temperature, storage capacity and the price of the elements. The search space includes all alkaline earth, 3d and 4d metals in combination with chloride......, bromide or iodide, and mixtures thereof. In total the search space consists of thousands of combinations, which makes a GA ideal, to reduce the number of necessary calculations. We are screening for a one step release from either a hexa or octa ammine, and we have found promising candidates, which...

Cylinder supplied ammonia scrubber testing in IDMS

International Nuclear Information System (INIS)

Lambert, D.P.

1994-01-01

This report summarizes the results of the off-line testing the Integrated DWPF Melter System (IDMS) ammonia scrubbers using ammonia supplied from cylinders. Three additional tests with ammonia are planned to verify the data collected during off-line testing. Operation of the ammonia scrubber during IDMS SRAT and SME processing will be completed during the next IDMS run. The Sludge Receipt and Adjustment Tank (SRAT) and Slurry Mix Evaporator (SME) scrubbers were successful in removing ammonia from the vapor stream to achieve ammonia vapor concentrations far below the 10 ppM vapor exit design basis. In most of the tests, the ammonia concentration in the vapor exit was lower than the detection limit of the analyzers so results are generally reported as <0.05 parts per million (ppM). During SRAT scrubber testing, the ammonia concentration was no higher than 2 ppM and during SME testing the ammonia concentration was no higher than 0.05 m

Study on treatment of distilled ammonia waste water from coke plant with activated carbon-NaClO catalytic oxidation method

Energy Technology Data Exchange (ETDEWEB)

Luo, D.; Yi, P.; Liu, J.; Chen, A. [Xiangtan Polytechnic University, Xiangtan (China). Dept. of Chemical Enginering

2001-12-01

Catalytic oxidation method for the treatment of distilled ammonia waste water from coke plant was investigated using activated carbon as catalyst and NaClO as oxidant. The influences of main factors, such as NaClO, activated carbon, pH and reactionary time were discussed. The results showed that under the conditions of 25{degree}C, NaClO/CODO=1.5, carbon/NaClO=0.6 and pH=3.0, the reaction completed within 120 minutes with 99.5% of phenol removal and 75.8% of COD removal when the distilled ammonia waste water from coke plant which containing phenol 510 mg/L and CODO 8420 mg/L was treated. 13 refs., 4 figs.

Improved [13N]ammonia yield from the proton irradiation of water using methane gas

International Nuclear Information System (INIS)

Krasikova, R.N.; Fedorova, O.S.; Korsakov, M.V.; Landmeier Bennington, B.; Berridge, M.S.

1999-01-01

Production of N-13 ammonia directly in the cyclotron target has previously been accomplished by use of hydrogen pressurization or by addition of organic compounds, chiefly ethanol. All methods enjoy limited success and then either fail to produce ammonia at high beam dose, or require very high pressures to maintain ammonia production. We report that low-pressure methane gas in the target results in production of radiochemically pure ammonia throughout the feasible range of target irradiation conditions

CADDIS Volume 2. Sources, Stressors and Responses: Ammonia

Science.gov (United States)

Introduction to the ammonia module, when to list ammonia as a candidate cause, ways to measure ammonia, simple and detailed conceptual diagrams for ammonia, literature reviews and references for the ammonia module.

Counteracting ammonia inhibition during anaerobic digestion by recovery using submersible microbial desalination cell.

Science.gov (United States)

Zhang, Yifeng; Angelidaki, Irini

2015-07-01

Ammonia inhibition is one of the most frequent and serious problems in biogas plants. In this study, a novel hybrid system consisting of a submersible microbial desalination cell (SMDC) and a continuous stirred tank reactor (CSTR) was developed for counteracting ammonia inhibition during anaerobic digestion (AD) with simultaneous in situ ammonia recovery and electricity production. The SMDC was powered by acetate in a buffer solution, while synthetic ammonia-rich wastewater was used as the feeding of the CSTR. Under continuous operation, ammonia recovery rate of 86 g-N/m(2) /day and current density of 4.33 A/m(2) were achieved at steady-state condition. As a result, 112% extra biogas was produced due to ammonia recovery by the SMDC. High-throughput sequencing showed that ammonia recovery had an impact on the microbial community structures in the SMDC and CSTR. Considering the additional economic benefits of biogas enhancement and possible wastewater treatment, the SMDC may represent a cost-effective and environmentally friendly method for waste resources recovery and biomethanation of ammonia-rich residues. © 2015 Wiley Periodicals, Inc.

Ammonia-based quantum computer

International Nuclear Information System (INIS)

Ferguson, Andrew J.; Cain, Paul A.; Williams, David A.; Briggs, G. Andrew D.

2002-01-01

We propose a scheme for quantum computation using two eigenstates of ammonia or similar molecules. Individual ammonia molecules are confined inside fullerenes and used as two-level qubit systems. Interaction between these ammonia qubits takes place via the electric dipole moments, and in particular we show how a controlled-NOT gate could be implemented. After computation the qubit is measured with a single-electron electrometer sensitive enough to differentiate between the dipole moments of different states. We also discuss a possible implementation based on a quantum cellular automaton

ENGINEERING DESIGN CONFIGURATIONS FOR BIOLOGICAL AMMONIA REMOVAL

Science.gov (United States)

Many regions in the United States have excessive levels of nutrients including ammonia in their source waters. For example, farming and agricultural sources of ammonia in the Midwest contribute to relatively high levels of ammonia in many ground waters. Although ammonia in water ...

Hydrogen bonding-mediated dehydrogenation in the ammonia borane combined graphene oxide systems

Science.gov (United States)

Kuang, Anlong; Liu, Taijuan; Kuang, Minquan; Yang, Ruifeng; Huang, Rui; Wang, Guangzhao; Yuan, Hongkuan; Chen, Hong; Yang, Xiaolan

2018-03-01

The dehydrogenation of ammonia borane (AB) adsorbed on three different graphene oxide (GO) sheets is investigated within the ab initio density functional theory. The energy barriers to direct combination the hydrogens of hydroxyl groups and the hydridic hydrogens of AB to release H2 are relatively high, indicating that the process is energetically unfavorable. Our theoretical study demonstrates that the dehydrogenation mechanism of the AB-GO systems has undergone two critical steps, first, there is the formation of the hydrogen bond (O-H-O) between two hydroxyl groups, and then, the hydrogen bond further react with the hydridic hydrogens of AB to release H2 with low reaction barriers.

Rectal administration of /sup 13/N-ammonia in the study of ammonia metabolism

Energy Technology Data Exchange (ETDEWEB)

Koen, H [Chiba Univ. (Japan). School of Medicine

1980-08-01

/sup 13/N-ammonia produced by the cyclotron was instilled intrarectally in patients with liver diseases for the study of the turnover of rectally absorbed /sup 13/N-ammonia. A positron camera connected to an on-line computer system was used for imaging of the liver and heart; /sup 13/N-activity over the head was also recorded. Sequential changes of /sup 13/N-activity in blood was measured, and chromatographic analysis of /sup 13/N-labeled substances in blood was carried out using a Dowex 50W x 8 column. In the control, /sup 13/N-ammonia was absorbed quickly into blood visualizing the liver shortly after administration, and hepatic uptake of /sup 13/N-ammonia reached a plateau in 10 -- 15 min, whereas in patients with cirrhosis, the lung and heart were visualized in 5 min when the liver image was still faint. /sup 13/N-activity over the head was apparently higher in the cirrhotic group. It was suggested that a large proportion of absorbed /sup 13/N-ammonia bypassed liver cells and reached peripheral tissues. The heart/liver ratio of /sup 13/N and /sup 13/N over the head were closely correlated with various indices of portal hypertension. The relative proportion of /sup 13/N-metabolites in blood was lower at 5 min and 15 min after administration in cirrhosis, suggesting a reduced capacity of the liver to remove and metabolize ammonia.

Ammonia Synthesis at Low Pressure.

Science.gov (United States)

Cussler, Edward; McCormick, Alon; Reese, Michael; Malmali, Mahdi

2017-08-23

Ammonia can be synthesized at low pressure by the use of an ammonia selective absorbent. The process can be driven with wind energy, available locally in areas requiring ammonia for synthetic fertilizer. Such wind energy is often called "stranded," because it is only available far from population centers where it can be directly used. In the proposed low pressure process, nitrogen is made from air using pressure swing absorption, and hydrogen is produced by electrolysis of water. While these gases can react at approximately 400 °C in the presence of a promoted conventional catalyst, the conversion is often limited by the reverse reaction, which makes this reaction only feasible at high pressures. This limitation can be removed by absorption on an ammine-like calcium or magnesium chloride. Such alkaline metal halides can effectively remove ammonia, thus suppressing the equilibrium constraints of the reaction. In the proposed absorption-enhanced ammonia synthesis process, the rate of reaction may then be controlled not by the chemical kinetics nor the absorption rates, but by the rate of the recycle of unreacted gases. The results compare favorably with ammonia made from a conventional small scale Haber-Bosch process.

Ammonia for hydrogen storage: challenges and opportunities

DEFF Research Database (Denmark)

Klerke, Asbjørn; Christensen, Claus H.; Nørskov, Jens Kehlet

2008-01-01

The possibility of using ammonia as a hydrogen carrier is discussed. Compared to other hydrogen storage materials, ammonia has the advantages of a high hydrogen density, a well-developed technology for synthesis and distribution, and easy catalytic decomposition. Compared to hydrocarbons...... and alcohols, it has the advantage that there is no CO2 emission at the end user. The drawbacks are mainly the toxicity of liquid ammonia and the problems related to trace amounts of ammonia in the hydrogen after decomposition. Storage of ammonia in metal ammine salts is discussed, and it is shown...... that this maintains the high volumetric hydrogen density while alleviating the problems of handling the ammonia. Some of the remaining challenges for research in ammonia as a hydrogen carrier are outlined....

Tetraammineplatinum(II dichloride ammonia tetrasolvate

Directory of Open Access Journals (Sweden)

Tobias Grassl

2014-07-01

Full Text Available The title compound, [Pt(NH34]Cl2·4NH3, was crystallized in liquid ammonia from the salt PtCl2. The platinum cation is coordinated by four ammonia molecules, forming a square-planar complex. The chloride anions are surrounded by nine ammonia molecules, either bound within the platinum complex or solvent molecules. The solvent ammonia molecules are packed in such a way that an extended network of N—H...N and N—H...Cl hydrogen bonds is formed. The structure is isotypic with [Pd(NH34]Cl2·4NH3 [Grassl & Korber (2014. Acta Cryst. E70, i32].

Doppler spectroscopy of hydrogen Balmer lines in a hollow cathode glow discharge in ammonia and argon-ammonia mixture

International Nuclear Information System (INIS)

Sisovic, N. M.; Konjevic, N.

2008-01-01

The results of Doppler spectroscopy of hydrogen Balmer lines from a stainless steel (SS) and copper (Cu) hollow cathode (HC) glow discharge in ammonia and argon-ammonia mixture are reported. The experimental profiles in ammonia discharge are fitted well by superposing three Gaussian profiles. The half widths, in energy units, of narrow and medium Gaussians are in the ranges 0.3-0.4 eV and 3-4 eV, respectively, for both hollow cathodes what is expected on the basis of earlier electron beam→NH 3 experiments. The half widths of the largest Gaussian in ammonia are 46 and 55 eV for SS and Cu HC, respectively. In argon-ammonia discharge, three Gaussians are also required to fit experimental profiles. While half widths of narrow and medium Gaussians are similar to those in ammonia, the half widths of the largest Gaussians are 35 and 42 eV for SS and Cu HC, respectively. The half widths of the largest Gaussians in ammonia and in argon-ammonia mixture indicate the presence of excessive Doppler broadening.

Detoxification of ammonia in mouse cortical GABAergic cell cultures increases neuronal oxidative metabolism and reveals an emerging role for release of glucose-derived alanine

DEFF Research Database (Denmark)

Leke, Renata; Bak, Lasse Kristoffer; Anker, Malene

2011-01-01

Cerebral hyperammonemia is believed to play a pivotal role in the development of hepatic encephalopathy (HE), a debilitating condition arising due to acute or chronic liver disease. In the brain, ammonia is thought to be detoxified via the activity of glutamine synthetase, an astrocytic enzyme....... Moreover, it has been suggested that cerebral tricarboxylic acid (TCA) cycle metabolism is inhibited and glycolysis enhanced during hyperammonemia. The aim of this study was to characterize the ammonia-detoxifying mechanisms as well as the effects of ammonia on energy-generating metabolic pathways...... in a mouse neuronal-astrocytic co-culture model of the GABAergic system. We found that 5 mM ammonium chloride affected energy metabolism by increasing the neuronal TCA cycle activity and switching the astrocytic TCA cycle toward synthesis of substrate for glutamine synthesis. Furthermore, ammonia exposure...

A fast and effective method for N-doping TiO{sub 2} by post treatment with liquid ammonia: visible light photocatalysis

Energy Technology Data Exchange (ETDEWEB)

Powell, Michael J.; Palgrave, Robert G.; Dunnill, Charles W.; Parkin, Ivan P.

2014-07-01

TiO{sub 2} thin films prepared by sol–gel synthesis were N-doped by post treating with liquid ammonia and annealing at 500 °C. Characterisation by X-ray diffraction and Raman spectroscopy confirmed that the anatase crystal type was retained and present in all samples. Scanning electron microscopy showed that treatment with liquid ammonia had no significant effect on the film morphology. Functional testing under filtered while light conditions involving water contact angle, and the photo destruction of both Resazurin and Stearic acid showed the ammonia treated samples to be active visible light photocatalysts in contrast to the pure TiO{sub 2} and the blank controls. X-ray Photoelectron Spectroscopy studies indicate the presence of interstitial nitrogen (N{sub 1s} = 400 eV) suggesting that the origin of the enhanced photocatalytic activity is most likely due to oxygen vacancies created by the interstitial nitrogen incorporation. This synthesis method utilises a simple, inexpensive and highly effective post treatment route to N-dope TiO{sub 2} and produces visible light photocatalysts with potential applications in self-cleaning and healthcare environments. - Highlights: • Synthesis and characterisation of N-doped TiO{sub 2} thin films • N-doping by a post treatment with liquid ammonia • Enhanced photocatalytic activity • Easy enhancement of current TiO{sub 2} based technologies.

Ammonia as a Suitable Fuel for Fuel Cells

International Nuclear Information System (INIS)

Lan, Rong; Tao, Shanwen

2014-01-01

Ammonia, an important basic chemical, is produced at a scale of 150 million tons per year. Half of hydrogen produced in chemical industry is used for ammonia production. Ammonia containing 17.5 wt% hydrogen is an ideal carbon-free fuel for fuel cells. Compared to hydrogen, ammonia has many advantages. In this mini-review, the suitability of ammonia as fuel for fuel cells, the development of different types of fuel cells using ammonia as the fuel and the potential applications of ammonia fuel cells are briefly reviewed.

Tritiated ammonia formation

International Nuclear Information System (INIS)

Heung, L.K.

1995-01-01

When nitrogen was selected as the glovebox atmosphere for the Replacement Tritium Facility (RTF) at the Savannah River Site (SRS), a concern was raised as to the possibility of tritiated ammonia formation in the gloveboxes. Experimental data were produced to study the tritiated ammonia formation rate in a tritium and nitrogen mixture. A rate equation that closely simulates the experimental data was developed. This rate equation can be used to calculate the formation of tritiated ammonia from different concentrations of tritium and nitrogen. The reaction of T 2 and N 2 to form NT 3 is a slow process, particularly when the tritium concentration is low. The reaction requires weeks or months to reach radiochemical equilibrium dependent on the concentrations of the reactants. 4 refs., 6 figs., 1 tab

(Bio)electrochemical ammonia recovery

NARCIS (Netherlands)

Kuntke, P.; Sleutels, T.H.J.A.; Rodríguez Arredondo, M.; Georg, S.; Barbosa, S.G.; Heijne, Ter A.; Hamelers, Hubertus V.M.; Buisman, C.J.N.

2018-01-01

In recent years, (bio)electrochemical systems (B)ES have emerged as an energy efficient alternative for the recovery of TAN (total ammonia nitrogen, including ammonia and ammonium) from wastewater. In these systems, TAN is removed or concentrated from the wastewater under the influence of an

Ammonia vapor sensing properties of polyaniline-titanium(IV)phosphate cation exchange nanocomposite.

Science.gov (United States)

Khan, Asif Ali; Baig, Umair; Khalid, Mohd

2011-02-28

In this study, the electrically conducting polyaniline-titanium(IV)phosphate (PANI-TiP) cation exchange nanocomposite was synthesized by sol-gel method. The cation exchange nanocomposite based sensor for detection of ammonia vapors was developed at room temperature. It was revealed that the sensor showed good reversible response towards ammonia vapors ranging from 3 to 6%. It was found that the sensor with p-toluene sulphonic acid (p-TSA) doped exhibited higher sensing response than hydrochloric acid doped. This sensor has detection limit ≤1% ammonia. The response of resistivity changes of the cation exchange nanocomposite on exposure to different concentrations of ammonia vapors shows its utility as a sensing material. These studies suggest that the cation exchange nanocomposite could be a good material for ammonia sensor at room temperature. Copyright © 2010 Elsevier B.V. All rights reserved.

Bioaugmentation as a solution to increase methane production from an ammonia-rich substrate

DEFF Research Database (Denmark)

Fotidis, Ioannis; Wang, Han; Fiedel, Nicolai Russell

2014-01-01

production yield. To date there are not any reliable methods to alleviate the ammonia toxicity effect and/or to efficiently digest ammonia-rich waste. In the current study, bioaugmentation as a possible method to alleviate ammonia toxicity effect in a mesophilic continuously stirred-tank reactor (CSTR......) operating under “inhibited steady state” was tested. A fast growing hydrogenotrophic methanogen (i.e. Methanoculleus bourgensis MS2T) was bioaugmented in the CSTR reactor at high ammonia levels (5 g NH4+-N L-1). A second CSTR reactor used as control with no bioaugmentation. The results derived from...... this study clearly demonstrated a 31.3% increase in methane production yield in the CSTR reactor, at steady-state, after bioaugmentation. Additionally, high-throughput 16S rRNA gene sequencing analysis showed a fivefold increase in relative abundance of Methanoculleus spp. after bioaugmentation. On contrary...

Ammonia as a suitable fuel for fuel cells

Directory of Open Access Journals (Sweden)

Rong eLan

2014-08-01

Full Text Available Ammonia, an important basic chemical, is produced at a scale of 150 million tons per year. Half of hydrogen produced in chemical industry is used for ammonia production. Ammonia containing 17.5wt% hydrogen is an ideal carbon-free fuel for fuel cells. Compared to hydrogen, ammonia has many advantages. In this mini-review, the suitability of ammonia as fuel for fuel cells, the development of different types of fuel cells using ammonia as the fuel and the potential applications of ammonia fuel cells are briefly reviewed.

Ammonia slip measurements on ships with NO{sub x} converters. A study of different techniques

Energy Technology Data Exchange (ETDEWEB)

Fridell, Erik; Steen, Erica (IVL, Goeteborg (SE))

2007-12-15

A number of techniques to measure the concentration of ammonia in exhaust gas have been evaluated. The objective is to obtain reliable methods for measuring ammonia slip from ships equipped with SCR systems for cleaning of nitrogen oxide emissions. The methods tested are FTIR, laser absorption, a wet chemical method and a method where ammonia is oxidised into NO{sub x} over a catalyst. The laser method is an in-situ technique, where the transmitter and receiver are positioned on opposite flanges at the exhaust channel, while the other methods are ex-situ, i. e., a probe volume of gas is taken from the exhaust channel into the instrumentation. The laser method worked well in the field studies and gave results with high sensitivity and good time resolution. FTIR did not work well for low concentrations. The time resolution is good but with a delay. In cases with an uneven distribution of ammonia throughout the exhaust channel, the concentration will vary depending on the location of the probe. A strong influence of the oxygen concentration on the observed ammonia concentration was found in the laboratory study. The wet chemical method gave reliable results. The time resolution is poor and the method is sensitive to uneven distribution in the exhaust channel. The method with the oxidation catalyst worked well in the lab but not in field where the catalyst was deactivated, probably by sulphur

Method for Bacterial Growth and Ammonia Production and Effect of Inhibitory Substances in Disposable Absorbent Hygiene Products.

Science.gov (United States)

Forsgren-Brusk, Ulla; Yhlen, Birgitta; Blomqvist, Marie; Larsson, Peter

The purpose of this study was to evaluate a pragmatic laboratory method to provide a technique for developing incontinence products better able to reduce malodor when used in the clinical setting. Bacterial growth and bacterially formed ammonia in disposable absorbent incontinence products was measured by adding synthetic urine inoculated with bacteria to test samples cut from the crotch area of the product. The inhibitory effect's of low pH (4.5 and 4.9) and 3 antimicrobial substances-chlorhexidine, polyhexamethylene biguanide (PHMB), and thymol-at 2 concentrations each, were studied. From the initial inocula of 3.3 log colony-forming units per milliliter (cfu/mL) at baseline, the bacterial growth of the references increased to 5.0 to 6.0 log cfu/mL at 6 hours for Escherichia coli, Proteus mirabilis, and Enterococcus faecalis. At 12 hours there was a further increase to 7.0 to 8.9 log cfu/mL. Adjusting the pH of the superabsorbent in the incontinence product from 6.0 to pH 4.5 and pH 4.9 significantly (P disposable absorbent products to inhibit bacterial growth and ammonia production. This technique, we describe, provides a pragmatic method for assessing the odor-inhibiting capacity of specific incontinence products.

Ammonia tolerant enriched methanogenic cultures as bioaugmentation inocula to alleviate ammonia inhibition in continuous anaerobic reactors

DEFF Research Database (Denmark)

Fotidis, Ioannis; Wang, Han; Angelidaki, Irini

Ammonia is the most common inhibitor of anaerobic digestion (AD) process, resulting in suboptimal exploitation of the biogas potential of the feedstocks, causing significant economic losses to the biogas plants. Ammonia is mainly inhibiting the aceticlastic methanogens, while the hydrogenotrophic...... methanogens are more robust to ammonia toxicity effect. It has been shown that bioaugmentation of a pure strain of a hydrogenotrophic methanogen (i.e. Methanoculleus bourgensis) in an ammonia inhibited continuous anaerobic reactor can improve methane production more than 30%. Nevertheless, cultivation...... tolerant methanogenic culture as potential bioaugmentation inoculum in a continuous stirred tank reactor (CSTR) operating under “inhibited steady-state”, triggered by high ammonia levels (5 g NH4+-N L-1). The results of the current study established for the first time that bioaugmentation of an enriched...

Tetraamminepalladium(II dichloride ammonia tetrasolvate

Directory of Open Access Journals (Sweden)

Tobias Grassl

2014-07-01

Full Text Available The title compound, [Pd(NH34]Cl2·4NH3, was crystallized in liquid ammonia from the salt Pd(enCl2 (en is ethylenediamine and is isotypic with [Pt(NH34]Cl2·4NH3 [Grassl & Korber (2014. Acta Cryst. E70, i31]. The Pd2+ cation is coordinated by four ammonia molecules, exhibiting a square-planar geometry. The chloride anions are surrounded by nine ammonia molecules. These are either bound in the palladium complex or solvent molecules. The packing of the ammonia solvent molecules enables the formation of an extended network of N—H...N and N—H...Cl interactions with nearly ideal hydrogen-bonding geometry.

Synthesis of ammonia directly from air and water at ambient temperature and pressure

Science.gov (United States)

Lan, Rong; Irvine, John T. S.; Tao, Shanwen

2013-01-01

The N≡N bond (225 kcal mol−1) in dinitrogen is one of the strongest bonds in chemistry therefore artificial synthesis of ammonia under mild conditions is a significant challenge. Based on current knowledge, only bacteria and some plants can synthesise ammonia from air and water at ambient temperature and pressure. Here, for the first time, we report artificial ammonia synthesis bypassing N2 separation and H2 production stages. A maximum ammonia production rate of 1.14 × 10−5 mol m−2 s−1 has been achieved when a voltage of 1.6 V was applied. Potentially this can provide an alternative route for the mass production of the basic chemical ammonia under mild conditions. Considering climate change and the depletion of fossil fuels used for synthesis of ammonia by conventional methods, this is a renewable and sustainable chemical synthesis process for future. PMID:23362454

Synthesis of ammonia directly from air and water at ambient temperature and pressure.

Science.gov (United States)

Lan, Rong; Irvine, John T S; Tao, Shanwen

2013-01-01

The N≡N bond (225 kcal mol⁻¹) in dinitrogen is one of the strongest bonds in chemistry therefore artificial synthesis of ammonia under mild conditions is a significant challenge. Based on current knowledge, only bacteria and some plants can synthesise ammonia from air and water at ambient temperature and pressure. Here, for the first time, we report artificial ammonia synthesis bypassing N₂ separation and H₂ production stages. A maximum ammonia production rate of 1.14 × 10⁻⁵ mol m⁻² s⁻¹ has been achieved when a voltage of 1.6 V was applied. Potentially this can provide an alternative route for the mass production of the basic chemical ammonia under mild conditions. Considering climate change and the depletion of fossil fuels used for synthesis of ammonia by conventional methods, this is a renewable and sustainable chemical synthesis process for future.

Dynamic study of ammonia metabolism after rectal administration of /sup 13/N-ammonia

Energy Technology Data Exchange (ETDEWEB)

Koen, H; Arimizu, N; Musha, H; Okuda, K; Tateno, Y [Chiba Univ. (Japan). School of Medicine

1980-01-01

/sup 13/N-ammonia produced by cyclotron, short lived positron emitter (Tl/2 10 min) was instilled intrarectally in a dose of 15 - 30 mCi with liver disease, in order to study the dynamic metabolism of rectally absorbed /sup 13/N-ammonia. A NIRS positron camera connected with an on-line computer system was used for imaging of the liver and heart. /sup 13/N-activity over the head was recorded by detectors used in renography. Sequential changes of /sup 13/N-activity in blood was measured, and chromatographic analysis of /sup 13/N-labeled substances in blood was performed using Dowex 50 W x 8. In the control, /sup 13/N-ammonia was absorbed quickly into blood visualizing the liver shortly after administration, and hepatic uptake of /sup 13/N-ammonia reached a plateau in 10 - 15 min, whereas in patients with cirrhosis, the lung and heart were visualized in 5 min when the liver image was still faint. /sup 13/N-activity over the head was apparently higher in the cirrhotic group compared with the control. It was suggested that a large proportion of injected /sup 13/N-ammonia bypassed liver cells and reached peripheral tissues. We determined the heart/liver activity ratio and this ratio at 15 min was found to be closely correlated with various indices of portal hypertension. The percentages of /sup 13/N-metabolite in blood at 5 min and 15 min were lower in the cirrhotic, suggesting reduced capacity of the liver to remove /sup 13/N-ammonia in cirrhosis.

Ammonia chemistry in a flameless jet

Energy Technology Data Exchange (ETDEWEB)

Zieba, Mariusz; Schuster, Anja; Scheffknecht, Guenter [Institute of Process Engineering and Power Plant Technology, University of Stuttgart, Pfaffenwaldring 23, D-70569 Stuttgart (Germany); Brink, Anders; Hupa, Mikko [Process Chemistry Centre, Aabo Akademi University, Biskopsgatan 8, 20500 Aabo (Finland)

2009-10-15

In this paper, the nitrogen chemistry in an ammonia (NH{sub 3}) doped flameless jet is investigated using a kinetic reactor network model. The reactor network model is used to explain the main differences in ammonia chemistry for methane (CH{sub 4})-containing fuels and methane-free fuels. The chemical pathways of nitrogen oxides (NO{sub x}) formation and destruction are identified using rate-of-production analysis. The results show that in the case of natural gas, ammonia reacts relatively late at fuel lean condition leading to high NO{sub x} emissions. In the pre-ignition zone, the ammonia chemistry is blocked due to the absence of free radicals which are consumed by methane-methyl radical (CH{sub 3}) conversion. In the case of methane-free gas, the ammonia reacted very rapidly and complete decomposition was reached in the fuel rich region of the jet. In this case the necessary radicals for the ammonia conversion are generated from hydrogen (H{sub 2}) oxidation. (author)

The obtaining of iron acetate from processed iron comprising catalyst of ammonia synthesis

International Nuclear Information System (INIS)

Mansurov, M.M.; Lugovenko, A.N.; Mirzoeva, M.M.

1993-01-01

Present article is devoted to obtaining of iron acetate from processed iron comprising catalyst of ammonia synthesis. The method of synthesis of iron acetate from processed iron comprising catalyst of ammonia synthesis was elaborated. The structure of complex was determined.

Ammonia excretion in Caenorhabditis elegans: mechanism and evidence of ammonia transport of the Rhesus protein CeRhr-1

Science.gov (United States)

Adlimoghaddam, Aida; Boeckstaens, Mélanie; Marini, Anna-Maria; Treberg, Jason R.; Brassinga, Ann-Karen C.; Weihrauch, Dirk

2015-01-01

ABSTRACT The soil-dwelling nematode Caenorhabditis elegans is a bacteriovorous animal, excreting the vast majority of its nitrogenous waste as ammonia (25.3±1.2 µmol gFW−1 day−1) and very little urea (0.21±0.004 µmol gFW−1 day−1). Although these roundworms have been used for decades as genetic model systems, very little is known about their strategy to eliminate the toxic waste product ammonia from their bodies into the environment. The current study provides evidence that ammonia is at least partially excreted via the hypodermis. Starvation reduced the ammonia excretion rates by more than half, whereas mRNA expression levels of the Rhesus protein CeRhr-2, V-type H+-ATPase (subunit A) and Na+/K+-ATPase (α-subunit) decreased correspondingly. Moreover, ammonia excretion rates were enhanced in media buffered to pH 5 and decreased at pH 9.5. Inhibitor experiments, combined with enzyme activity measurements and mRNA expression analyses, further suggested that the excretion mechanism involves the participation of the V-type H+-ATPase, carbonic anhydrase, Na+/K+-ATPase, and a functional microtubule network. These findings indicate that ammonia is excreted, not only by apical ammonia trapping, but also via vesicular transport and exocytosis. Exposure to 1 mmol l−1 NH4Cl caused a 10-fold increase in body ammonia and a tripling of ammonia excretion rates. Gene expression levels of CeRhr-1 and CeRhr-2, V-ATPase and Na+/K+-ATPase also increased significantly in response to 1 mmol l−1 NH4Cl. Importantly, a functional expression analysis showed, for the first time, ammonia transport capabilities for CeRhr-1 in a phylogenetically ancient invertebrate system, identifying these proteins as potential functional precursors to the vertebrate ammonia-transporting Rh-glycoproteins. PMID:25740900

46 CFR 154.1760 - Liquid ammonia.

Science.gov (United States)

2010-10-01

... 46 Shipping 5 2010-10-01 2010-10-01 false Liquid ammonia. 154.1760 Section 154.1760 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR....1760 Liquid ammonia. The master shall ensure that no person sprays liquid ammonia into a cargo tank...

Stabilities of protonated water-ammonia clusters

Science.gov (United States)

Sundén, A. E. K.; Støchkel, K.; Hvelplund, P.; Brøndsted Nielsen, S.; Dynefors, B.; Hansen, K.

2018-05-01

Branching ratios of water and ammonia evaporation have been measured for spontaneous evaporation from protonated mixed clusters H+(H2O)n(NH3)m in the size range 0 ≤ n ≤ 11 and 0 ≤ m ≤ 7. Mixed clusters evaporate water except for clusters containing six or more ammonia molecules, indicating the formation of a stable core of one ammonium ion surrounded by four ammonia molecules and a second shell consisting predominantly of water. We relate evaporative branching ratios to free energy differences between the products of competing channels and determine the free energy differences for clusters with up to seven ammonia molecules. Clusters containing up to five ammonia molecules show a very strong scaling of these free energy differences.

Ammonia sensing properties of silver nanocomposite with polypyrrole

Science.gov (United States)

Karmakar, N. S.; Kothari, D. C.; Bhat, N. V.

2013-02-01

Silver-polypyrrole nanocomposite thin film was prepared by a novel method. UV-Vis spectroscopic studies confirmed the presence of silver nanoparticles and also polymerization of pyrrole surrounding the silver nanoparticles. All the important X-ray diffraction peaks corresponding to silver were present in the composites. The silver nanoparticles and its composites with polypyrrole were observed by SEM and TEM. Electrical conductivity measurements were carried out using two probe method and it was found that the conductivity of nanocomposites is 10-5 S/cm. It was found that functionalized silver nanoparticles can act as efficient gas sensor for ammonia. The present result of the increase in conductivity with ammonia exposure is in contrast with the previously reported results of the decrease in conductivity.

Titan's Ammonia Feature

Science.gov (United States)

Smythe, W.; Nelson, R.; Boryta, M.; Choukroun, M.

2011-01-01

NH3 has long been considered an important component in the formation and evolution of the outer planet satellites. NH3 is particularly important for Titan, since it may serve as the reservoir for atmospheric nitrogen. A brightening seen on Titan starting in 2004 may arise from a transient low-lying fog or surface coating of ammonia. The spectral shape suggests the ammonia is anhydrous, a molecule that hydrates quickly in the presence of water.

27 CFR 21.96 - Ammonia, aqueous.

Science.gov (United States)

2010-04-01

... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Ammonia, aqueous. 21.96 Section 21.96 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT... Ammonia, aqueous. (a) Alkalinity. Strongly alkaline to litmus. (b) Ammonia content. 27 to 30 percent by...

Mobility Spectrometer Studies on Hydrazine and Ammonia Detection

Science.gov (United States)

Niu, William; Eiceman, Gary; Szumlas, Andrew; Lewis, John

2011-01-01

An airborne vapor analyzer for detecting sub- to low- parts-per-million (ppm) hydrazine in the presence of higher concentration levels of ammonia has been under development for the Orion program. The detector is based on ambient pressure ionization and ion mobility characterization. The detector encompasses: 1) a membrane inlet to exclude particulate and aerosols from the analyzer inlet; 2) a method to separate hydrazine from ammonia which would otherwise lead to loss of calibration and quantitative accuracy for the hydrazine determination; and 3) response and quantitative determinations for both hydrazine and ammonia. Laboratory studies were made to explore some of these features including mobility measurements mindful of power, size, and weight issues. The study recommended the use of a mobility spectrometer of traditional design with a reagent gas and equipped with an inlet transfer line of bonded phase fused silica tube. The inlet transfer line provided gas phase separation of neutrals of ammonia from hydrazine at 50 C simplifying significantly the ionization chemistry that underlies response in a mobility spectrometer. Performance of the analyzer was acceptable between ranges of 30 to 80 C for both the pre-fractionation column and the drift tube. An inlet comprised of a combined membrane with valve-less injector allowed high speed quantitative determination of ammonia and hydrazine without cross reactivity from common metabolites such as alcohols, esters, and aldehydes. Preliminary test results and some of the design features are discussed.

Ammonia-oxidizing Bacteria and Archaea in the Rhizosphere of Freshwater Macrophytes

DEFF Research Database (Denmark)

Herrmann, Martina; Schramm, Andreas

2007-01-01

AMMONIA-OXIDIZING ARCHAEA AND BACTERIA IN THE RHIZOSPHERE OF FRESHWATER MACROPHYTES Martina Herrmann and Andreas Schramm Department of Biological Sciences, Microbiology, University of Aarhus, Denmark Aquatic macrophytes such as Littorella uniflora and Lobelia dortmanna release oxygen from...... their roots and thereby stimulate nitrification and coupled nitrification-denitrification in their rhizosphere. However, oxygen release and inorganic nitrogen concentrations differ markedly between macrophyte species. We therefore propose (i) that the rhizosphere of freshwater macrophytes harbours a species......-specific microbial community distinct from that of unvegetated sediment and (ii) that aquatic macrophytes have an impact on abundance and activity of nitrifying and denitrifying bacteria in freshwater sediment. The goal of this study was to test these hypotheses for the key functional group for coupled nitrification...

Do freshwater macrophytes influence the community structure of ammonia-oxidizing and denitrifying bacteria in the rhizospere?

DEFF Research Database (Denmark)

Herrmann, Martina; Schramm, Andreas

2006-01-01

to unvegetated sediment, especially with respect to the availability of oxygen, organic carbon, and inorganic nitrogen. We hypothesize that macrophyte species create specific niches for ammonia oxidizing and nitrate-reducing bacteria in their rhizosphere, leading to plant-dependant differences in abundance...... dortmanna have been shown to release oxygen from their roots and to stimulate nitrification and coupled nitrification-denitrification in the rhizosphere. Together with the excretion of root exudates, this effect leads to strongly modified microenvironments at the root surface and in the rhizosphere compared......-denitrification using the 15N isotope pairing technique. Ammonia-oxidizing and nitrate-reducing populations are analyzed based on the ammonia monooxygenase gene (amoA) and the nitrate reductase gene (narG) as functional markers. Preliminary data indicate that there in fact exist differences in the community composition...

Efficient regeneration of partially spent ammonia borane fuel

International Nuclear Information System (INIS)

Davis, Benjamin Lee; Gordon, John C.; Stephens, Frances; Dixon, David A.; Matus, Myrna H.

2008-01-01

A necessary target in realizing a hydrogen (H 2 ) economy, especially for the transportation sector, is its storage for controlled delivery, presumably to an energy producing fuel cell. In this vein, the U.S. Department of Energy's (DOE) Centers of Excellence (CoE) in Hydrogen Storage have pursued different methodologies, including metal hydrides, chemical hydrides, and sorbents, for the expressed purpose of supplanting gasoline's current > 300 mile driving range. Chemical hydrogen storage has been dominated by one appealing material, ammonia borane (H 3 B-NH 3 , AB), due to its high gravimetric capacity of hydrogen (19.6 wt %) and low molecular weight (30.7 g mol -1 ). In addition, AB has both hydridic and protic moieties, yielding a material from which H2 can be readily released. As such, a number of publications have described H 2 release from amine boranes, yielding various rates depending on the method applied. Even though the viability of any chemical hydrogen storage system is critically dependent on efficient recyclability, reports on the latter subject are sparse, invoke the use of high energy reducing agents, and suffer from low yields. For example, the DOE recently decided to no longer pursue the use of NaBH 4 as a H 2 storage material, in part because of inefficient regeneration. We thus endeavored to find an energy efficient regeneration process for the spent fuel from H 2 depleted AB with a minimum number of steps.

Ammonia control and neurocognitive outcome among urea cycle disorder patients treated with glycerol phenylbutyrate.

Science.gov (United States)

Diaz, George A; Krivitzky, Lauren S; Mokhtarani, Masoud; Rhead, William; Bartley, James; Feigenbaum, Annette; Longo, Nicola; Berquist, William; Berry, Susan A; Gallagher, Renata; Lichter-Konecki, Uta; Bartholomew, Dennis; Harding, Cary O; Cederbaum, Stephen; McCandless, Shawn E; Smith, Wendy; Vockley, Gerald; Bart, Stephen A; Korson, Mark S; Kronn, David; Zori, Roberto; Merritt, J Lawrence; C S Nagamani, Sandesh; Mauney, Joseph; Lemons, Cynthia; Dickinson, Klara; Moors, Tristen L; Coakley, Dion F; Scharschmidt, Bruce F; Lee, Brendan

2013-06-01

Glycerol phenylbutyrate is under development for treatment of urea cycle disorders (UCDs), rare inherited metabolic disorders manifested by hyperammonemia and neurological impairment. We report the results of a pivotal Phase 3, randomized, double-blind, crossover trial comparing ammonia control, assessed as 24-hour area under the curve (NH3 -AUC0-24hr ), and pharmacokinetics during treatment with glycerol phenylbutyrate versus sodium phenylbutyrate (NaPBA) in adult UCD patients and the combined results of four studies involving short- and long-term glycerol phenylbutyrate treatment of UCD patients ages 6 and above. Glycerol phenylbutyrate was noninferior to NaPBA with respect to ammonia control in the pivotal study, with mean (standard deviation, SD) NH3 -AUC0-24hr of 866 (661) versus 977 (865) μmol·h/L for glycerol phenylbutyrate and NaPBA, respectively. Among 65 adult and pediatric patients completing three similarly designed short-term comparisons of glycerol phenylbutyrate versus NaPBA, NH3 -AUC0-24hr was directionally lower on glycerol phenylbutyrate in each study, similar among all subgroups, and significantly lower (P < 0.05) in the pooled analysis, as was plasma glutamine. The 24-hour ammonia profiles were consistent with the slow-release behavior of glycerol phenylbutyrate and better overnight ammonia control. During 12 months of open-label glycerol phenylbutyrate treatment, average ammonia was normal in adult and pediatric patients and executive function among pediatric patients, including behavioral regulation, goal setting, planning, and self-monitoring, was significantly improved. Glycerol phenylbutyrate exhibits favorable pharmacokinetics and ammonia control relative to NaPBA in UCD patients, and long-term glycerol phenylbutyrate treatment in pediatric UCD patients was associated with improved executive function (ClinicalTrials.gov NCT00551200, NCT00947544, NCT00992459, NCT00947297). (HEPATOLOGY 2012). Copyright © 2012 American Association for the

Statistical sampling method for releasing decontaminated vehicles

International Nuclear Information System (INIS)

Lively, J.W.; Ware, J.A.

1996-01-01

Earth moving vehicles (e.g., dump trucks, belly dumps) commonly haul radiologically contaminated materials from a site being remediated to a disposal site. Traditionally, each vehicle must be surveyed before being released. The logistical difficulties of implementing the traditional approach on a large scale demand that an alternative be devised. A statistical method (MIL-STD-105E, open-quotes Sampling Procedures and Tables for Inspection by Attributesclose quotes) for assessing product quality from a continuous process was adapted to the vehicle decontamination process. This method produced a sampling scheme that automatically compensates and accommodates fluctuating batch sizes and changing conditions without the need to modify or rectify the sampling scheme in the field. Vehicles are randomly selected (sampled) upon completion of the decontamination process to be surveyed for residual radioactive surface contamination. The frequency of sampling is based on the expected number of vehicles passing through the decontamination process in a given period and the confidence level desired. This process has been successfully used for 1 year at the former uranium mill site in Monticello, Utah (a CERCLA regulated clean-up site). The method forces improvement in the quality of the decontamination process and results in a lower likelihood that vehicles exceeding the surface contamination standards are offered for survey. Implementation of this statistical sampling method on Monticello Projects has resulted in more efficient processing of vehicles through decontamination and radiological release, saved hundreds of hours of processing time, provided a high level of confidence that release limits are met, and improved the radiological cleanliness of vehicles leaving the controlled site

Heavy water production by the method of ammonia rectification with heat pump. Experience of starting of industrial installation

International Nuclear Information System (INIS)

Rozen, A.M.

1995-01-01

Basic results of the start-up in 1955 of a facility for heavy water production by ammonia refining are presented to substantiate its economic profitability. The description of the facility is given, data on the materials corrosion resistance, efficiency of the operation of the trays and pumps are provided. It is shown that the mentioned method of heavy water production in terms of economic indices is similar to highly efficient methods, namely: refining of liquid hydrogen and water-hydrogen sulfide two-temperature isotopic exchange. 14 refs., 14 figs., 2 tabs

Process for synthesis of ammonia borane for bulk hydrogen storage

Science.gov (United States)

Autrey, S Thomas [West Richland, WA; Heldebrant, David J [Richland, WA; Linehan, John C [Richland, WA; Karkamkar, Abhijeet J [Richland, WA; Zheng, Feng [Richland, WA

2011-03-01

The present invention discloses new methods for synthesizing ammonia borane (NH.sub.3BH.sub.3, or AB). Ammonium borohydride (NH.sub.4BH.sub.4) is formed from the reaction of borohydride salts and ammonium salts in liquid ammonia. Ammonium borohydride is decomposed in an ether-based solvent that yields AB at a near quantitative yield. The AB product shows promise as a chemical hydrogen storage material for fuel cell powered applications.

A study on a real-time leak detection method for pressurized liquid refrigerant pipeline based on pressure and flow rate

International Nuclear Information System (INIS)

Tian, Shen; Du, Juanli; Shao, Shuangquan; Xu, Hongbo; Tian, Changqing

2016-01-01

Highlights: • A real-time leak detection method is developed for ammonia pipeline in cold storage. • A locating algorithm based on pressure difference profile is provided. • This method is validated by R22 and ammonia leak experiments. • The minimum detectable leak ratio is 1% for R22 and 4% for ammonia. • The location estimating errors are −27% ~ 17% for R22 and −27% ~ 27% for ammonia. - Graphical Abstract: - Abstract: Leakage from pressurized liquid ammonia pipeline has been a serious problem in large commercial cold storages because it might release large amount of liquid ammonia and without safety supervision in daily operations. The present paper shows a detection method for a pressurized liquid ammonia pipeline with a leak. The variations of pressure, flow rate and pressure difference profile are studied. A leak indicator (σ), proposed with the one-dimensional steady-state flow model, is used to detect the leak occurrence by comparing it with a threshold value (σ Le ). A locating algorithm based on pressure difference profile along the pipeline is also proposed, which has considered the effect of the static pressure increase at the leak point. Experiments on different leak positions and ratios from liquid R22 and ammonia pipelines are carried out to validate this method. It is found that, with a relatively low false alarm rate (as three percent), the minimum detectable leak ratio reached 1% for the R22 pipeline and 4% for the ammonia pipeline. The locating errors are between −27% ~ 17% for R22 pipeline and −27% ~ 27% for ammonia pipeline.

Modeling and simulation of ammonia removal from purge gases of ammonia plants using a catalytic Pd-Ag membrane reactor

International Nuclear Information System (INIS)

Rahimpour, M.R.; Asgari, A.

2008-01-01

In this work, the removal of ammonia from synthesis purge gas of an ammonia plant has been investigated. Since the ammonia decomposition is thermodynamically limited, a membrane reactor is used for complete decomposition. A double pipe catalytic membrane reactor is used to remove ammonia from purge gas. The purge gas is flowing in the reaction side and is converted to hydrogen and nitrogen over nickel-alumina catalyst. The hydrogen is transferred through the Pd-Ag membrane of tube side to the shell side. A mathematical model including conservation of mass in the tube and shell side of reactor is proposed. The proposed model was solved numerically and the effects of different parameters on the rector performance were investigated. The effects of pressure, temperature, flow rate (sweep ratio), membrane thickness and reactor diameter have been investigated in the present study. Increasing ammonia conversion was observed by raising the temperature, sweep ratio and reducing membrane thickness. When the pressure increases, the decomposition is gone toward completion but, at low pressure the ammonia conversion in the outset of reactor is higher than other pressures, but complete destruction of the ammonia cannot be achieved. The proposed model can be used for design of an industrial catalytic membrane reactor for removal of ammonia from ammonia plant and reducing NO x emissions

Effects of land-applied ammonia scrubber solutions on yield, nitrogen uptake, soil test phosphorus and phosphorus runoff

Science.gov (United States)

Ammonia (NH3) scrubbers reduce amounts of NH3 and dust released from animal rearing facilities, while generating nitrogen (N) rich solutions, which may be used as fertilizer. The objective of this study was to determine the effects of various NH3 scrubber solutions on yields, N uptake by forage, so...

Manufacture of a Polyaniline Nanofiber Ammonia Sensor Integrated with a Readout Circuit Using the CMOS-MEMS Technique

Directory of Open Access Journals (Sweden)

Chyan-Chyi Wu

2009-02-01

Full Text Available This study presents the fabrication of a polyaniline nanofiber ammonia sensor integrated with a readout circuit on a chip using the commercial 0.35 mm complementary metal oxide semiconductor (CMOS process and a post-process. The micro ammonia sensor consists of a sensing resistor and an ammonia sensing film. Polyaniline prepared by a chemical polymerization method was adopted as the ammonia sensing film. The fabrication of the ammonia sensor needs a post-process to etch the sacrificial layers and to expose the sensing resistor, and then the ammonia sensing film is coated on the sensing resistor. The ammonia sensor, which is of resistive type, changes its resistance when the sensing film adsorbs or desorbs ammonia gas. A readout circuit is employed to convert the resistance of the ammonia sensor into the voltage output. Experimental results show that the sensitivity of the ammonia sensor is about 0.88 mV/ppm at room temperature

Theoretical study of Moessbauer hyperfine parameters of Fe bound to ammonia

International Nuclear Information System (INIS)

Terra, J.; Guenzburger, D.

1995-01-01

The first-principles Discrete Variational method was employed to study the species formed by the interaction of an Fe atom and ammonia. Total energy calculations were performed for several configurations. The hyperfine parameters isomer shift, quadrupole splitting and magnetic hyperfine were calculated for the ground state found, and compared to reported experimental values obtained by Moessbauer spectroscopy in frozen ammonia. (author). 14 refs, 1 tab

Manure application and ammonia volatilization

NARCIS (Netherlands)

Huijsmans, J.F.M.

2003-01-01

Keywords: manure application, ammonia volatilization, environmental conditions, application technique, incorporation technique, draught force, work organization, costs Livestock manure applied on farmland is an important source of ammonia (NH3) volatilization, and NH3 is a major atmospheric

Synthesis of ammonia with microwave plasma

International Nuclear Information System (INIS)

Xu Wenguo; Yu Aimin; Liu Jun; Jin Qinhan

1991-01-01

THe synthesis of ammonia absorbed on 13X zeolite with the aid of microwave plasma is described. The ammonia molecule absorbed on 13X zeolite as ammonium ions were detected by IR spectroscopy. The results obtained show that the ammonia synthesis is facilitated by the surface reactions of NH x (x = 1, 2) radicals adsorbed on zeolite with hydrogen atoms

Peripheral Ammonia as a Mediator of Methamphetamine Neurotoxicity

Science.gov (United States)

Halpin, Laura E.; Yamamoto, Bryan K.

2012-01-01

Ammonia is metabolized by the liver and has established neurological effects. The current study examined the possibility that ammonia contributes to the neurotoxic effects of methamphetamine (METH). The results show that a binge dosing regimen of METH to the rat increased plasma and brain ammonia concentrations that were paralleled by evidence of hepatotoxicity. The role of peripheral ammonia in the neurotoxic effects of METH was further substantiated by the demonstration that the enhancement of peripheral ammonia excretion blocked the increases in brain and plasma ammonia and attenuated the long term depletions of dopamine and serotonin typically produced by METH. Conversely, the localized perfusion of ammonia in combination with METH, but not METH alone or ammonia alone, into the striatum recapitulated the neuronal damage produced by the systemic administration of METH. Furthermore, this damage produced by the local administration of ammonia and METH was blocked by the GYKI 52466, an AMPA receptor antagonist. These findings highlight the importance of ammonia derived from the periphery as a small molecule mediator of METH neurotoxicity and more broadly emphasize the importance of peripheral organ damage as a possible mechanism that mediates the neuropathology produced by drugs of abuse and other neuroactive molecules. PMID:22993432

Ammonia gas permeability of meat packaging materials.

Science.gov (United States)

Karim, Faris; Hijaz, Faraj; Kastner, Curtis L; Smith, J Scott

2011-03-01

Meat products are packaged in polymer films designed to protect the product from exterior contaminants such as light, humidity, and harmful chemicals. Unfortunately, there is almost no data on ammonia permeability of packaging films. We investigated ammonia permeability of common meat packaging films: low-density polyethylene (LDPE; 2.2 mil), multilayer polyolefin (MLP; 3 mil), and vacuum (V-PA/PE; 3 mil, 0.6 mil polyamide/2.4 mil polyethylene). The films were fabricated into 10 × 5 cm pouches and filled with 50 mL deionized water. Pouches were placed in a plexiglass enclosure in a freezer and exposed to 50, 100, 250, or 500 ppm ammonia gas for 6, 12, 24, and 48 h at -17 ± 3 °C and 21 ± 3 °C. At freezing temperatures, no ammonia residues were detected and no differences in pH were found in the water. At room temperature, ammonia levels and pH of the water increased significantly (P packaging materials have low ammonia permeability and protect meat products exposed to ammonia leaks during frozen storage.

A porous SiC ammonia sensor

NARCIS (Netherlands)

Connolly, E.J.; Timmer, B.H.; Pham, H.T.M.; Groeneweg, J.; Sarro, P.M.; Olthuis, Wouter; French, P.J.

2005-01-01

When used as the dielectric in a capacitive sensing arrangement, porous SiC has been found to be extremely sensitive to the presence of ammonia (NH3) gas. The exact sensing method is still not clear, but NH3 levels as low as 0.5 ppm could be detected. We report the fabrication and preliminary

Cerebral ammonia metabolism in hyperammonemic rats

Energy Technology Data Exchange (ETDEWEB)

Cooper, A J; Mora, S N; Cruz, N F; Gelbard, A S

1985-06-01

The short-term metabolic fate of blood-borne (/sup 13/N)ammonia was determined in the brains of chronically (8- or 14-week portacaval-shunted rats) or acutely (urease-treated) hyperammonemic rats. Using a freeze-blowing technique it was shown that the overwhelming route for metabolism of blood-borne (/sup 13/N)ammonia in normal, chronically hyperammonemic and acutely hyperammonemic rat brain was incorporation into glutamine (amide). However, the rate of turnover of (/sup 13/N)ammonia to L-(amide-/sup 13/N)glutamine was slower in the hyperammonemic rat brain than in the normal rat brain. The activities of several enzymes involved in cerebral ammonia and glutamate metabolism were also measured in the brains of 14-week portacaval-shunted rats. The rat brain appears to have little capacity to adapt to chronic hyperammonemia because there were no differences in activity compared with those of weight-matched controls for the following brain enzymes involved in glutamate/ammonia metabolism: glutamine synthetase, glutamate dehydrogenase, aspartate aminotransferase, glutamine transaminase, glutaminase, and glutamate decarboxylase. The present findings are discussed in the context of the known deleterious effects on the CNS of high ammonia levels in a variety of diseases.

Ammonia stress under high environmental ammonia induces Hsp70 and Hsp90 in the mud eel, Monopterus cuchia.

Science.gov (United States)

Hangzo, Hnunlalliani; Banerjee, Bodhisattwa; Saha, Shrabani; Saha, Nirmalendu

2017-02-01

The obligatory air-breathing mud eel (Monopterus cuchia) is frequently being challenged with high environmental ammonia (HEA) exposure in its natural habitats. The present study investigated the possible induction of heat shock protein 70 and 90 (hsp70, hsc70, hsp90α and hsp90β) genes and more expression of Hsp70 and Hsp90 proteins under ammonia stress in different tissues of the mud eel after exposure to HEA (50 mM NH 4 Cl) for 14 days. HEA resulted in significant accumulation of toxic ammonia in different body tissues and plasma, which was accompanied with the stimulation of oxidative stress in the mud eel as evidenced by more accumulation of malondialdehyde (MDA) and hydrogen peroxide (H 2 O 2 ) during exposure to HEA. Further, hyper-ammonia stress led to significant increase in the levels of mRNA transcripts for inducible hsp70 and hsp90α genes and also their translated proteins in different tissues probably as a consequence of induction of hsp70 and hsp90α genes in the mud eel. However, hyper-ammonia stress was neither associated with any significant alterations in the levels of mRNA transcripts for constitutive hsc70 and hsp90β genes nor their translated proteins in any of the tissues studied. More abundance of Hsp70 and Hsp90α proteins might be one of the strategies adopted by the mud eel to defend itself from the ammonia-induced cellular damages under ammonia stress. Further, this is the first report of ammonia-induced induction of hsp70 and hsp90α genes under hyper-ammonia stress in any freshwater air-breathing teleost.

Ammonia and ammonium hydroxide sensors for ammonia/water absorption machines: Literature review and data compilation

Energy Technology Data Exchange (ETDEWEB)

Anheier, N.C. Jr.; McDonald, C.E.; Cuta, J.M.; Cuta, F.M.; Olsen, K.B.

1995-05-01

This report describes an evaluation of various sensing techniques for determining the ammonia concentration in the working fluid of ammonia/water absorption cycle systems. The purpose of this work was to determine if any existing sensor technology or instrumentation could provide an accurate, reliable, and cost-effective continuous measure of ammonia concentration in water. The resulting information will be used for design optimization and cycle control in an ammonia-absorption heat pump. PNL researchers evaluated each sensing technology against a set of general requirements characterizing the potential operating conditions within the absorption cycle. The criteria included the physical constraints for in situ operation, sensor characteristics, and sensor application. PNL performed an extensive literature search, which uncovered several promising sensing technologies that might be applicable to this problem. Sixty-two references were investigated, and 33 commercial vendors were identified as having ammonia sensors. The technologies for ammonia sensing are acoustic wave, refractive index, electrode, thermal, ion-selective field-effect transistor (ISFET), electrical conductivity, pH/colormetric, and optical absorption. Based on information acquired in the literature search, PNL recommends that follow-on activities focus on ISFET devices and a fiber optic evanescent sensor with a colormetric indicator. The ISFET and fiber optic evanescent sensor are inherently microminiature and capable of in situ measurements. Further, both techniques have been demonstrated selective to the ammonium ion (NH{sub 4}{sup +}). The primary issue remaining is how to make the sensors sufficiently corrosion-resistant to be useful in practice.

New findings on cerebral ammonia uptake in HE using functional (13)N-ammonia PET

DEFF Research Database (Denmark)

Sørensen, Michael; Keiding, Susanne

2007-01-01

PET is a functional imaging technique suitable for studies of brain ammonia metabolism. Dynamic (13)N-ammonia PET yields time-courses of radioactivity concentrations in brain (PET camera) and blood (samples). Ahl et al. (Hepatology 40:73-79, 2004) and Keiding et al. (Hepatology 43:42-50, 2006...

Ammonia synthesis from N2 and H2O using a lithium cycling electrification strategy at atmospheric pressure

DEFF Research Database (Denmark)

McEnaney, Joshua M.; Singh, Aayush R.; Schwalbe, Jay A.

2017-01-01

Ammonia production is imperative to providing food for a growing world population. However, the primary method of synthetic ammonia production, the Haber Bosch process, is resource demanding and unsustainable. Here we report a novel ammonia production strategy, exemplified in an electrochemical...... lithium cycling process, which provides a pathway to sustainable ammonia synthesis via the ability to directly couple to renewable sources of electricity and can facilitate localized production. Whereas traditional aqueous electrochemical approaches are typically dominated by the hydrogen evolution...... reaction (HER), we are able to circumvent the HER by using a stepwise approach which separates the reduction of N2 from subsequent protonation to NH3, thus our synthesis method is predominantly selective for ammonia production. Density functional theory calculations for thermodynamic and diffusion energy...

Flexible ammonia handling strategies using both cutaneous and branchial epithelia in the highly ammonia-tolerant Pacific hagfish.

Science.gov (United States)

Clifford, Alexander M; Weinrauch, Alyssa M; Edwards, Susan L; Wilkie, Michael P; Goss, Greg G

2017-08-01

Hagfish consume carrion, potentially exposing them to hypoxia, hypercapnia, and high environmental ammonia (HEA). We investigated branchial and cutaneous ammonia handling strategies by which Pacific hagfish ( Eptatretus stoutii ) tolerate and recover from high ammonia loading. Hagfish were exposed to HEA (20 mmol/l) for 48 h to elevate plasma total ammonia (T Amm ) levels before placement into divided chambers for a 4-h recovery period in ammonia-free seawater where ammonia excretion ( J Amm ) was measured independently in the anterior and posterior compartments. Localized HEA exposures were also conducted by subjecting hagfish to HEA in either the anterior or posterior compartments. During recovery, HEA-exposed animals increased J Amm in both compartments, with the posterior compartment comprising ~20% of the total J Amm compared with ~11% in non-HEA-exposed fish. Plasma T Amm increased substantially when whole hagfish and the posterior regions were exposed to HEA. Alternatively, plasma T Amm did not elevate after anterior localized HEA exposure. J Amm was concentration dependent (0.05-5 mmol/l) across excised skin patches at up to eightfold greater rates than in skin sections that were excised from HEA-exposed hagfish. Skin excised from more posterior regions displayed greater J Amm than those from more anterior regions. Immunohistochemistry with hagfish-specific anti-rhesus glycoprotein type c (α-hRhcg; ammonia transporter) antibody was characterized by staining on the basal aspect of hagfish epidermis while Western blotting demonstrated greater expression of Rhcg in more posterior skin sections. We conclude that cutaneous Rhcg proteins are involved in cutaneous ammonia excretion by Pacific hagfish and that this mechanism could be particularly important during feeding. Copyright © 2017 the American Physiological Society.

A Zinc Oxide Nanorod Ammonia Microsensor Integrated with a Readout Circuit on-a-Chip

Directory of Open Access Journals (Sweden)

Chyan-Chyi Wu

2011-11-01

Full Text Available A zinc oxide nanorod ammonia microsensor integrated with a readout circuit on-a-chip fabricated using the commercial 0.35 mm complementary metal oxide semiconductor (CMOS process was investigated. The structure of the ammonia sensor is composed of a sensitive film and polysilicon electrodes. The ammonia sensor requires a post-process to etch the sacrificial layer, and to coat the sensitive film on the polysilicon electrodes. The sensitive film that is prepared by a hydrothermal method is made of zinc oxide. The sensor resistance changes when the sensitive film adsorbs or desorbs ammonia gas. The readout circuit is used to convert the sensor resistance into the voltage output. Experiments show that the ammonia sensor has a sensitivity of about 1.5 mV/ppm at room temperature.

A reproducible accelerated in vitro release testing method for PLGA microspheres.

Science.gov (United States)

Shen, Jie; Lee, Kyulim; Choi, Stephanie; Qu, Wen; Wang, Yan; Burgess, Diane J

2016-02-10

The objective of the present study was to develop a discriminatory and reproducible accelerated in vitro release method for long-acting PLGA microspheres with inner structure/porosity differences. Risperidone was chosen as a model drug. Qualitatively and quantitatively equivalent PLGA microspheres with different inner structure/porosity were obtained using different manufacturing processes. Physicochemical properties as well as degradation profiles of the prepared microspheres were investigated. Furthermore, in vitro release testing of the prepared risperidone microspheres was performed using the most common in vitro release methods (i.e., sample-and-separate and flow through) for this type of product. The obtained compositionally equivalent risperidone microspheres had similar drug loading but different inner structure/porosity. When microsphere particle size appeared similar, porous risperidone microspheres showed faster microsphere degradation and drug release compared with less porous microspheres. Both in vitro release methods investigated were able to differentiate risperidone microsphere formulations with differences in porosity under real-time (37 °C) and accelerated (45 °C) testing conditions. Notably, only the accelerated USP apparatus 4 method showed good reproducibility for highly porous risperidone microspheres. These results indicated that the accelerated USP apparatus 4 method is an appropriate fast quality control tool for long-acting PLGA microspheres (even with porous structures). Copyright © 2015 Elsevier B.V. All rights reserved.

Chirality dependent interaction of ammonia with carbon nanotubes

Science.gov (United States)

Talukdar, Keka; Shantappa, Anil

2018-04-01

For the specific structure and extraordinary properties, carbon nanotubes (CNTs) have many applications in diversified fields. The interaction of CNTs with ammonia is a very interesting matter to study as it is related to the application of CNTs as ammonia sensor. Here the interaction of single walled zigzag, armchair and chiral carbon nanotubes is studied in respect of the change in energies before and after binding with ammonia by molecular dynamics simulation. Their deformation after simulation is modeled. The change of thermal conductivity of the CNTs is also found by simulation. The potential energy before and after absorption of ammonia gives useful information of the system. Thermal conductivities of the ammonia bound CNTs are changed considerably. It is observed that the potential energy and thermal conductivity both are changing for the interaction with ammonia and hence they are sensitive to ammonia binding.

The environmental risk prediction for Odessa city in the case of ammonia emissions from Odessa Port Plant

Directory of Open Access Journals (Sweden)

Sergiy V. Melnik

2015-06-01

Full Text Available In this paper, we consider the environmental risk prediction for Odessa's citizens in the case of ammonia emissions from Odessa Port Plant. The potential risk of ammonia emission can be calculated by multiplying the probability of an accident and the probability of human health damage. One of the steps in the quantitative risk assessment is the analysis of weather conditions such as wind direction. From 1899 wind-rose analysis shows an increasing the frequency of winds direction which is dangerous for the city. The ammonia concentration in the city can be calculated by the TOXI ver.2.2 method, based on the Gaussian dispersion model for pollutants in the atmosphere. The magnitude of risk was assessed by two methods: the US EPA method, and Integrated Hygienic Method, based on normal probability distribution. The results of the risk assessment for the two methods showed an acceptable risk for Odessa's citizens in the case of ammonia emissions into the atmosphere.

Observations of atmospheric ammonia from TANSO-FTS/GOSAT

Science.gov (United States)

Someya, Yu; Imasu, Ryoichi; Saitoh, Naoko; Shiomi, Kei

2017-04-01

Atmospheric ammonia has large impacts on the nitrogen cycles or atmospheric environment such as nucleation of PM2.5 particles. It is reported that ammonia in the atmosphere has been increasing rapidly with the growth of population globally and this trend must continue in the future. Satellite observation is an effective approach to get to know the global perspectives of the gas. Atmospheric ammonia is observable using the thermal infrared (TIR) spectra, and IASI, TES and CrIS had been revealed those distributions. GOSAT also has TIR band including the ammonia absorption bands. GOSAT has the shorter revisit cycle than that of the other hyper-spectral TIR sounders mentioned above, therefore, the shorter time-scale events can be represented. In addition to the importance of the impacts of ammonia itself, the concentration ratio between ammonia and the other trace gases such as CO which is one of the main targets of the GOSAT-2 project is useful as the indicator of their emission sources. In this study, we introduce an algorithm to retrieve the column amount of atmospheric ammonia based on non-linear optimal estimation (Rogers, 2000) from GOSAT spectra in the ammonia absorption band between 960 - 970 cm-1. Temperature and water vapor profiles are estimated in advance of the ammonia retrieval. The preliminary results showed significant high concentrations of ammonia in the Northern India and the Eastern China as pointed out in the previous researches. We will discuss the global distribution of ammonia in the presentation.

Effect of dietary protein restriction on renal ammonia metabolism

Science.gov (United States)

Lee, Hyun-Wook; Osis, Gunars; Handlogten, Mary E.; Guo, Hui; Verlander, Jill W.

2015-01-01

Dietary protein restriction has multiple benefits in kidney disease. Because protein intake is a major determinant of endogenous acid production, it is important that net acid excretion change in parallel during protein restriction. Ammonia is the primary component of net acid excretion, and inappropriate ammonia excretion can lead to negative nitrogen balance. Accordingly, we examined ammonia excretion in response to protein restriction and then we determined the molecular mechanism of the changes observed. Wild-type C57Bl/6 mice fed a 20% protein diet and then changed to 6% protein developed an 85% reduction in ammonia excretion within 2 days, which persisted during a 10-day study. The expression of multiple proteins involved in renal ammonia metabolism was altered, including the ammonia-generating enzymes phosphate-dependent glutaminase (PDG) and phosphoenolpyruvate carboxykinase (PEPCK) and the ammonia-metabolizing enzyme glutamine synthetase. Rhbg, an ammonia transporter, increased in expression in the inner stripe of outer medullary collecting duct intercalated cell (OMCDis-IC). However, collecting duct-specific Rhbg deletion did not alter the response to protein restriction. Rhcg deletion did not alter ammonia excretion in response to dietary protein restriction. These results indicate 1) dietary protein restriction decreases renal ammonia excretion through coordinated regulation of multiple components of ammonia metabolism; 2) increased Rhbg expression in the OMCDis-IC may indicate a biological role in addition to ammonia transport; and 3) Rhcg expression is not necessary to decrease ammonia excretion during dietary protein restriction. PMID:25925252

MEASUREMENT OF AMMONIA EMISSIONS FROM MECHANICALLY VENTILATED POULTRY HOUSES USING MULTIPATH TUNABLE DIODE LASER SPECTROSCOPY

Science.gov (United States)

Ammonia emissions from mechanically ventilated poultry operations are an important environmental concern. Open Path Tunable Diode Laser Absorption Spectroscopy has emerged as a robust real-time method for gas phase measurement of ammonia concentrations in agricultural settings. ...

Comparative study of ZnSe thin films deposited from modified chemical bath solutions with ammonia-containing and ammonia-free precursors

International Nuclear Information System (INIS)

Chen Liangyan; Zhang Daoli; Zhai Guangmei; Zhang Jianbing

2010-01-01

Ammonia is one of the complexing agents which are the most commonly used in the precursors of ZnSe thin films by chemical bath deposition, but its high volatility may be harmful to human beings and environments. In our experiments, ZnSe films were obtained from modified chemical solutions with ammonia-containing and ammonia-free precursors. X-ray diffraction, field-emission scanning electron microscope (FSEM), and absorption spectrum were applied to investigate the microstructure, morphology and optical properties of the samples obtained from both growth conditions, which were investigated in this work. The ammonia-free chemical bath deposited ZnSe films showed comparable properties with the ammonia-containing ones, indicating that ZnSe films from ammonia-free chemical solution may be preferred buffer layer in thin film solar cells with less environmental contamination.

Ammonia Uptake and Release in the MnX2–NH3 (X = Cl, Br Systems and Structure of the Mn(NH3nX2 (n = 6, 2 Ammines

Directory of Open Access Journals (Sweden)

Duncan H. Gregory

2012-04-01

Full Text Available Hexa-ammine complexes, Mn(NH36X2 (X = Cl, Br, have been synthesized by ammoniation of the corresponding transition metal halide and characterized by Powder X-ray diffraction (PXRD and Raman spectroscopy. The hexa-ammine complexes are isostructural (Cubic, Fm-3m, Z = 4; a = 10.2742(6 Å and 10.527(1 Å for X = Cl, Br respectively. Temperature programmed desorption (TPD demonstrated that ammonia release from Mn(NH36X2 complexes occurred in three stages corresponding to the release of 4, 1 and 1 NH3 equivalents respectively. The chloride and bromide both exhibit a deammoniation onset temperature below 323 K. The di-ammoniates from the first desorption step were isolated during TPD measurements and their crystal structures determined by Rietveld refinement against PXRD data (X = Cl: orthorhombic Cmmm, a = 8.1991(9 Å, b = 8.2498(7 Å, c = 3.8212(4 Å, Z = 2; X = Br: orthorhombic Pbam, a = 6.0109(5 Å, b = 12.022(1 Å, c = 4.0230(2 Å, Z = 2.

Ammonia synthesis. Ammonia synthesis by N₂ and steam electrolysis in molten hydroxide suspensions of nanoscale Fe₂O₃.

Science.gov (United States)

Licht, Stuart; Cui, Baochen; Wang, Baohui; Li, Fang-Fang; Lau, Jason; Liu, Shuzhi

2014-08-08

The Haber-Bosch process to produce ammonia for fertilizer currently relies on carbon-intensive steam reforming of methane as a hydrogen source. We present an electrochemical pathway in which ammonia is produced by electrolysis of air and steam in a molten hydroxide suspension of nano-Fe2O3. At 200°C in an electrolyte with a molar ratio of 0.5 NaOH/0.5 KOH, ammonia is produced at 1.2 volts (V) under 2 milliamperes per centimeter squared (mA cm(-2)) of applied current at coulombic efficiency of 35% (35% of the applied current results in the six-electron conversion of N2 and water to ammonia, and excess H2 is cogenerated with the ammonia). At 250°C and 25 bar of steam pressure, the electrolysis voltage necessary for 2 mA cm(-2) current density decreased to 1.0 V. Copyright © 2014, American Association for the Advancement of Science.

Optimization of biomethanation focusing on high ammonia loaded processes

DEFF Research Database (Denmark)

Wang, Han

, could theoretically mitigate the ammonia inhibition problem (Angelidaki et al., 1999). Therefore, the effect of co-digestion of cattle manure with lipids (i.e. glycerol trioleate (GTO)) under high ammonia levels (5 g NH4+-N·L-1) in anaerobic continuous stirred tank (CSTR) reactors (RGTO) was assessed....... Additionally, for comparison purposes, a soluble carbohydrate (i.e. glucose) was also used as a co-substrate in an identical CSTR reactor (RGLU). At 5 g NH4+-N·L-1, relative methane production of RGTO and RGLU, was 10.5% and 41% compared to the expected uninhibited production, respectively. At the same time....... The results derived from this study clearly demonstrated a 31.3% increase in methane production yield in the CSTR reactor, at steady-state, after bioaugmentation. It indicated that this new solution to counteract ammonia inhibition was more practical and effective compared with other methods applied today...

Artificial intelligent methods for thermodynamic evaluation of ammonia-water refrigeration systems

International Nuclear Information System (INIS)

Sencan, Arzu

2006-01-01

In this paper, Linear Regression and M5'Rules models within Data Mining Process and Artificial Neural Network (ANN) model for thermodynamic evaluation of ammonia-water absorption refrigeration systems was carried out. A new formulation based on ANN model is presented for the analysis of ammonia-water absorption refrigeration systems (AWRS) because the optimal result was obtained by using ANN Model. Thermodynamic analysis of the AWRS is very complex because of analytic functions used for calculating the properties of fluid couples and simulation programs. Therefore, it is extremely difficult to perform analysis of this system. COP and f are estimated depending on the temperatures of system component and concentration values. Using the weights obtained from the trained network a new formulation is presented for the calculation of the COP and f; the use of ANN is proliferating with high speed in simulation. The R 2 -values obtained when unknown data were used to the networks was 0.9996 and 0.9873 for the circulation ratio and COP respectively which is very satisfactory. The use of this new formulation, which can be employed with any programming language or spreadsheet program for the estimation of the circulation ratio and COP of AWRS, as described in this paper, may make the use of dedicated ANN software unnecessary

Hydrothermal Synthesis of PbTiO3 Nanocrystals with a pH-Adjusting Agent of Ammonia Solution

Science.gov (United States)

Li, Xinyi; Huang, Zhixiong; Zhang, Lianmeng; Guo, Dongyun

2018-05-01

The PbTiO3 nanocrystals were synthesized by a hydrothermal method, and ammonia solution was firstly used as a pH-adjusting agent. The effect of ammonia concentration on formation and morphologies of PbTiO3 nanocrystals was investigated. At low ammonia concentration (0-2.2 mol/L), no perovskite PbTiO3 phase was formed. When the ammonia concentration was 4.4 mol/L, the rod-like PbTiO3 nanocrystals with highly crystalline were successfully synthesized. As the ammonia concentration further increased to 13.2 mol/L, the flake-like PbTiO3 nanocrystals were formed.

Biotreatment of ammonia- and butanal-containing waste gases.

Science.gov (United States)

Weckhuysen, B; Vriens, L; Verachtert, H

1994-10-01

The biological removal of ammonia and butanal in contaminated air was investigated by using, respectively, a laboratory-scale filter and a scrubber-filter combination. It was shown that ammonia can be removed with an elimination efficiency of 83% at a volumetric load of 100 m3.m-2.h-1 with 4-16 ppm of ammonia. During the experiment percolates were analysed for nitrate, nitrite, ammonium and pH. It was found that the nitrification in the biofilter could deteriorate due to an inhibition of Nitrobacter species, when the free ammonia concentration was rising in the percolate. It should be easy to control such inhibition through periodic analysis of the liquid phase by using a filter-scrubber combination. Such a combination was studied for butanal removal. Butanal was removed with an elimination efficiency of 80% by a scrubber-filter combination at a volumetric load of 100 m3.m-2.h-1 and a high butanal input concentration. Mixing the filter material with CaCO3 and pH control of the liquid in the scrubber resulted in an increase of the elimination efficiency. These results, combined with previous results on the biofiltration of butanal and butyric acid, allow us to discuss the influence of odour compounds on the removal efficiency of such systems and methods for control. The results were used to construct a full-size system, which is described.

Purification of ammonia-containing trap waters from atomic power plant by ozone treatment

International Nuclear Information System (INIS)

Grachok, M.A.; Prokudina, S.A.; Shulyat'ev, M.I.

1990-01-01

The aim of research was to study the process of ozonation of ammonia-containing trap waters from the Kursk Atomic Power Plant both on the model solutions and on real ones. Different factors (pH of the medium, temperature, concentration of the initial substances) have been studied for their effect on ozonation of aqueous ammonia solutions, model solutions of trap waters from the Kursk Atomic Power Plant as well as ammonia-containing trap waters and liquid radioactive wastes delivered to special water treatment at the Kursk Atomic Power Plant. It is shown that in all the cases the highest rate of ammonia oxidation by ozone is observed in the alkaline medium (pH 1.4-11.0) and at 55 deg C. The obtained results have shown that a method of ozonation followed by evaporation of water to be purified can be used to treat ammonia-containing waters from atomic power plant

Ammonia in simulated Hanford double-shell tank wastes: Solubility and effects on surface tension

International Nuclear Information System (INIS)

Norton, J.D.; Pederson, L.R.

1994-09-01

Radioactive and wastes left from defense materials production activities are temporarily stored in large underground tanks at the Hanford Site in south central Washington State (Tank Waste Science Panel 1991). Some of these wastes are in the form of a thick slurry (''double-shell slurry'') containing sodium nitrate, sodium nitrite, sodium aluminate, sodium hydroxide, sodium carbonate, organic complexants and buffering agents, complexant fragments and other minor components (Herting et al. 1992a; Herting et al. 1992b; Campbell et al. 1994). As a result of thermal and radiolytic processes, a number of gases are known to be produced by some of these stored wastes, including ammonia, nitrous oxide, nitrogen, hydrogen, and methane (Babad et al. 1991; Ashby et al. 1992; Meisel et al. 1993; Ashby et al. 1993; Ashby et al. 1994; Bryan et al. 1993; US Department of Energy 1994). Before the emplacement of a mixer pump, these gases were retained in and periodically released from Tank 241-SY-101, a double-shell tank at the Hanford Site (Babad et al. 1992; US Department of Energy 1994). Gases are believed to be retained primarily in the form of bubbles attached to solid particles (Bryan, Pederson, and Scheele 1992), with very little actually dissolved in the liquid. Ammonia is an exception. The relation between the concentration of aqueous ammonia in such concentrated, caustic mixtures and the ammonia partial pressure is not well known, however

H$_2$ Production via Ammonia Decomposition Using Non-Noble Metal Catalysts: A Review

OpenAIRE

Bell, Tamsin; Torrente-Murciano, L

2016-01-01

The wide-spread implementation of the so-called hydrogen economy is currently partially limited by an economically feasible way of storing hydrogen. In this context, ammonia has been commonly presented as a viable option for chemical storage due its high hydrogen content (17.6 wt%). However, its use as an energy carrier requires the development of catalytic systems capable of releasing hydrogen at adequate rates and conditions. At the moment, the most active catalytic systems for the decompos...

Ammonia IR Absorbance Measurements with an Equilibrium Vapor Cell

National Research Council Canada - National Science Library

Field, Paul

2004-01-01

Infrared (IR) absorbance spectra were acquired for 18 ammonia vapor pressures. The vapor pressures were generated with 15 gravimetrically prepared aqueous solutions and three commercial aqueous solutions using a dynamic method I.E...

Ammonia production, excretion, toxicity, and defense in fish: A Review

Directory of Open Access Journals (Sweden)

Alex Y K Ip

2010-10-01

Full Text Available Many fishes are ammonotelic but some species can detoxify ammonia to glutamine or urea. Certain fish species can accumulate high levels of ammonia in the brain or defense against ammonia toxicity by enhancing the effectiveness of ammonia excretion through active NH4+ transport, manipulation of ambient pH, or reduction in ammonia permeability through the branchial and cutaneous epithelia. Recent reports on ammonia toxicity in mammalian brain reveal the importance of permeation of ammonia through the blood-brain barrier and passages of ammonia and water through transporters in the plasmalemma of brain cells. Additionally, brain ammonia toxicity could be related to the passage of glutamine through the mitochondrial membranes into the mitochondrial matrix. On the other hand, recent reports on ammonia excretion in fish confirm the involvement of Rhesus glycoproteins in the branchial and cutaneous epithelia. Therefore, this review focuses on both the earlier literature and the up-to-date information on the problems and mechanisms concerning the permeation of ammonia, as NH3, NH4+ or proton-neutral nitrogenous compounds, across mitochondrial membranes, the blood-brain barrier, the plasmalemma of neurons, and the branchial and cutaneous epithelia of fish. It also addresses how certain fishes with high ammonia tolerance defend against ammonia toxicity through the regulation of the permeation of ammonia and related nitrogenous compounds through various types of membranes. It is hoped that this review would revive the interests in investigations on the passage of ammonia through the mitochondrial membranes and the blood-brain barrier of ammonotelic fishes and fishes with high brain ammonia-tolerance, respectively.

Ammonia transport in the kidney by Rhesus glycoproteins

Science.gov (United States)

Verlander, Jill W.

2014-01-01

Renal ammonia metabolism is a fundamental element of acid-base homeostasis, comprising a major component of both basal and physiologically altered renal net acid excretion. Over the past several years, a fundamental change in our understanding of the mechanisms of renal epithelial cell ammonia transport has occurred, replacing the previous model which was based upon diffusion equilibrium for NH3 and trapping of NH4+ with a new model in which specific and regulated transport of both NH3 and NH4+ across renal epithelial cell membranes via specific membrane proteins is required for normal ammonia metabolism. A major advance has been the recognition that members of a recently recognized transporter family, the Rhesus glycoprotein family, mediate critical roles in renal and extrarenal ammonia transport. The erythroid-specific Rhesus glycoprotein, Rh A Glycoprotein (Rhag), was the first Rhesus glycoprotein recognized as an ammonia-specific transporter. Subsequently, the nonerythroid Rh glycoproteins, Rh B Glycoprotein (Rhbg) and Rh C Glycoprotein (Rhcg), were cloned and identified as ammonia transporters. They are expressed in specific cell populations and membrane domains in distal renal epithelial cells, where they facilitate ammonia secretion. In this review, we discuss the distribution of Rhbg and Rhcg in the kidney, the regulation of their expression and activity in physiological disturbances, the effects of genetic deletion on renal ammonia metabolism, and the molecular mechanisms of Rh glycoprotein-mediated ammonia transport. PMID:24647713

Nitrocarburising in ammonia-hydrocarbon gas mixtures

DEFF Research Database (Denmark)

Pedersen, Hanne; Christiansen, Thomas; Somers, Marcel A. J.

2010-01-01

The present work investigates the possibility of nitrocarburising in ammonia-acetylene-hydrogen and ammoniapropene- hydrogen gas mixtures, where unsaturated hydrocarbon gas is the carbon source during nitrocarburising. Consequently, nitrocarburising is carried out in a reducing atmosphere...... microscopy and X-ray diffraction analysis. It is shown that the use of unsaturated hydrocarbon gas in nitrocarburising processes is a viable alternative to traditional nitrocarburising methods....

Carbon-free H2 production from ammonia triggered at room temperature with an acidic RuO2/γ-Al2O3 catalyst.

Science.gov (United States)

Nagaoka, Katsutoshi; Eboshi, Takaaki; Takeishi, Yuma; Tasaki, Ryo; Honda, Kyoko; Imamura, Kazuya; Sato, Katsutoshi

2017-04-01

Ammonia has been suggested as a carbon-free hydrogen source, but a convenient method for producing hydrogen from ammonia with rapid initiation has not been developed. Ideally, this method would require no external energy input. We demonstrate hydrogen production by exposing ammonia and O 2 at room temperature to an acidic RuO 2 /γ-Al 2 O 3 catalyst. Because adsorption of ammonia onto the catalyst is exothermic, the catalyst bed is rapidly heated to the catalytic ammonia autoignition temperature, and subsequent oxidative decomposition of ammonia produces hydrogen. A differential calorimeter combined with a volumetric gas adsorption analyzer revealed a large quantity of heat evolved both with chemisorption of ammonia onto RuO 2 and acidic sites on the γ-Al 2 O 3 and with physisorption of multiple ammonia molecules.

Fabrication of interdigitated electrodes by inkjet printing technology for apllication in ammonia sensing

International Nuclear Information System (INIS)

Le, Duy Dam; Nguyen, Thi Ngoc Nhien; Doan, Duc Chanh Tin; Dang, Thi My Dung; Dang, Mau Chien

2016-01-01

In this paper interdigitated electrodes for gas sensors were fabricated by inkjet printing technology. Silver electrodes were inkjet printed on Si/SiO 2 substrates instead of traditional photolithography method. The inkjet printing parameters to obtain desired dimensions, thickness of the electrodes and distance between the interdigitated electrodes were optimized in this study. The fabricated interdigitated silver electrodes were tested for application in ammonia gas sensors. Conductive polyaniline (PANI) layer was coated on the silver interdigitated electrodes by drop-coating. Ammonia detection of the PANI-coated chips was characterized with a gas measurement system in which humidity and ammonia concentrations were well-controlled. The electrical conductivity of the PANI films coated on the electrodes was measured when the PANI films were exposed to nitrogen and ammonia. The conductivity of the PANI films decreased significantly due to the deprotonation process of PANI upon ammonia expodure. The recovery time was about 15 min by heating up the polymer chip at 60 °C. The results showed that the silver electrodes fabricated by inkjet printing technique could be used as a sensor platform for ammonia detection. (paper)

Study on Characteristics of Co-firing Ammonia/Methane Fuels under Oxygen Enriched Combustion Conditions

Science.gov (United States)

Xiao, Hua; Wang, Zhaolin; Valera-Medina, Agustin; Bowen, Philip J.

2018-06-01

Having a background of utilising ammonia as an alternative fuel for power generation, exploring the feasibility of co-firing ammonia with methane is proposed to use ammonia to substitute conventional natural gas. However, improvement of the combustion of such fuels can be achieved using conditions that enable an increase of oxygenation, thus fomenting the combustion process of a slower reactive molecule as ammonia. Therefore, the present study looks at oxygen enriched combustion technologies, a proposed concept to improve the performance of ammonia/methane combustion. To investigate the characteristics of ammonia/methane combustion under oxygen enriched conditions, adiabatic burning velocity and burner stabilized laminar flame emissions were studied. Simulation results show that the oxygen enriched method can help to significantly enhance the propagation of ammonia/methane combustion without changing the emission level, which would be quite promising for the design of systems using this fuel for practical applications. Furthermore, to produce low computational-cost flame chemistry for detailed numerical analyses for future combustion studies, three reduced combustion mechanisms of the well-known Konnov's mechanism were compared in ammonia/methane flame simulations under practical gas turbine combustor conditions. Results show that the reduced reaction mechanisms can provide good results for further analyses of oxygen enriched combustion of ammonia/methane. The results obtained in this study also allow gas turbine designers and modellers to choose the most suitable mechanism for further combustion studies and development.

Comparison of steam and ammonia pretreatment for enzymatic hydrolysis of cellulose

Energy Technology Data Exchange (ETDEWEB)

Mes-Hartree, M.; Dale, B.E.; Craig, W.K.

1988-11-01

Aspenwood, wheat straw, wheat chaff and alfalfa stems were treated under pressure with either steam or ammonia. The material was then water or methanol/water extracted. The extent of enzymatic hydrolysis of the cellulose portion of the treated substrates was compared using two different cellulases, a commercial preparation, Celluclast, and those from the fungus Trichoderma harzianum. Both steam and ammonia treatment enhanced the accessibility of the cellulose as measured by hydrolysis. Methanol extraction of steamed material generally reduced the access of the enzyme to the cellulose, whereas methanol extraction of ammonia-treated material increased accessibility. The optimum combinations of pretreatment and extraction method depended on the substrate and on the enzyme system; no treatment suitable for all situations could be selected.

Ammonia Test

Science.gov (United States)

... of Conditions Not Listed? Not Listed? Acidosis and Alkalosis Adrenal Insufficiency and Addison Disease Alcoholism Allergies Alzheimer ... ammonia, but both can damage the eyes, skin, respiratory tract, and, if swallowed, the mouth, throat, and ...

Upwind impacts of ammonia from an intensive poultry unit

International Nuclear Information System (INIS)

Jones, L.; Nizam, M.S.; Reynolds, B.; Bareham, S.; Oxley, E.R.B.

2013-01-01

This study investigated potential ammonia impacts on a sand dune nature reserve 600 m upwind of an intensive poultry unit. Ammonia concentrations and total nitrogen deposition were measured over a calendar year. A series of ammonia and nitrogen exposure experiments using dune grassland species were conducted in controlled manipulations and in the field. Ammonia emissions from the intensive poultry unit were detected up to 2.8 km upwind, contributing to exceedance of critical levels of ammonia 800 m upwind and exceedance of critical loads of nitrogen 2.8 km upwind. Emissions contributed 30% of the total N load in parts of the upwind conservation site. In the nitrogen exposure experiments, plants showed elevated tissue nitrogen contents, and responded to ammonia concentrations and nitrogen deposition loads observed in the conservation site by increasing biomass. Estimated long-term impacts suggest an increase in the soil carbon pool of 9% over a 50-year timescale. -- Highlights: •Ammonia from a poultry unit can be detected 2.8 km upwind. •Ammonia caused exceedance of critical levels 800 m and critical loads 2.8 km upwind. •Dune grassland species utilised ammonia as a nutrient source. •Plant biomass increased at low levels of ammonia and total nitrogen deposition. •Soil C pools are predicted to increase by 9% over 50 years due to the excess ammonia. -- Ammonia from a poultry unit has upwind impacts, exceeding critical levels 800 m and critical loads 2.8 km upwind, and increasing biomass and tissue N of dune grassland species

Staging properties of potassium-ammonia ternary graphite intercalation compounds at high ammonia pressure

Science.gov (United States)

Qian, X. W.; Solin, S. A.

1989-04-01

The pressure dependence of the (00l) x-ray diffraction patterns of the ternary graphite intercalation compound K(NH3)xC24 has been studied in the range 0.5-11 kbar (for which x~4.5) using a diamond anvil cell. A special apparatus for loading the cell with liquid ammonia at room temperature has been constructed and is briefly described. In these experiments, the pressure-transmitting fluid was also an intercalant, namely ammonia. Therefore, the chemical potential of this species was linearly coupled to the applied pressure in contrast to the usual case where the pressure-transmitting fluid is chemically passive. The pressure dependences of the basal spacings and of the relative intensities of key reflections have been measured, as have the compressibilities of the stage-1 and stage-2 components of the two-phase system. Basal-spacing anomalies and anomalies in the relative intensities occur at pressures of ~3.5 and 8.0 kbar and are tentatively attributed to in-plane coordination changes in the potassium-ammonia ratio. Using thermodynamic arguments and Le Chatelier's principle we show quantitatively that a staging phase transition from pure stage-1 phase to an admixture of stage-1 and stage-2 is expected with increased pressure above 10 bar in agreement with experiment. The saturation ammonia compositions (x values) of the admixed stages are found to be 4.5 and 5.4 for the stage-1 and -2 components, respectively. This result is interpreted as evidence that the composition is not sterically limited but is determined by the binding energy of ammonia for potassium and by the perturbation to this energy from the guest-host interaction.

A New Drug Release Method in Early Development of Transdermal Drug Delivery Systems

Directory of Open Access Journals (Sweden)

Bing Cai

2012-01-01

Full Text Available In vitro drug release tests are a widely used tool to measure the variance between transdermal product performances and required by many authorities. However, the result cannot provide a good estimation of the in vivo drug release. In the present work, a new method for measuring drug release from patches has been explored and compared with the conventional USP apparatus 2 and 5 methods. Durogesic patches, here used as a model patch, were placed on synthetic skin simulator and three moisture levels (29, 57, 198 μL cm−2 were evaluated. The synthetic skin simulators were collected after 1, 2, 3, 4, 6, and 24 hours and extracted with pH 1.0 hydrochloric acid solution. The drug concentrations in the extractions were measured by isocratic reverse phase high-pressure liquid chromatography. The results showed that, with the increasing moisture level on the synthetic skin simulator, the drug release rate increased. In comparison with the conventional USP method, the drug release results performed by the new method were in more correlation to the release rate claimed in the product label. This new method could help to differentiate the drug release rates among assorted formulations of transdermal drug delivery systems in the early stage of development.

Mechanism of ammonia excretion in the freshwater leech Nephelopsis obscura: characterization of a primitive Rh protein and effects of high environmental ammonia

Science.gov (United States)

Quijada-Rodriguez, Alex R.; Treberg, Jason R.

2015-01-01

Remarkably little is known about nitrogenous excretion in freshwater invertebrates. In the current study, the nitrogen excretion mechanism in the carnivorous ribbon leech, Nephelopsis obscura, was investigated. Excretion experiments showed that the ribbon leech is ammonotelic, excreting 166.0 ± 8.6 nmol·grams fresh weight (gFW)−1·h−1 ammonia and 14.7 ± 1.9 nmol·gFW−1·h−1 urea. Exposure to high and low pH hampered and enhanced, respectively, ammonia excretion rates, indicating an acid-linked ammonia trapping mechanism across the skin epithelia. Accordingly, compared with body tissues, the skin exhibited elevated mRNA expression levels of a newly identified Rhesus protein and at least in tendency the Na+/K+-ATPase. Pharmacological experiments and enzyme assays suggested an ammonia excretion mechanism that involves the V-ATPase, Na+/K+-ATPase, and carbonic anhydrase, but not necessarily a functional microtubule system. Most importantly, functional expression studies of the identified Rh protein cloned from leech skin tissue revealed an ammonia transport capability of this protein when expressed in yeast. The leech Rh-ammonia transporter (NoRhp) is a member of the primitive Rh protein family, which is a sister group to the common ancestor of vertebrate ammonia-transporting Rh proteins. Exposure to high environmental ammonia (HEA) caused a new adjustment of body ammonia, accompanied with a decrease in NoRhp and Na+/K+-ATPase mRNA levels, but unaltered ammonia excretion rates. To our knowledge, this is only the second comprehensive study regarding the ammonia excretion mechanisms in a freshwater invertebrate, but our results show that basic processes of ammonia excretion appear to also be comparable to those found in freshwater fish, suggesting an early evolution of ionoregulatory mechanisms in freshwater organisms. PMID:26180186

Study of Ammonia Emissions in a Ventilated Pig Pen

DEFF Research Database (Denmark)

Rong, Li

Pig productions cause a wide emission of odors, such as ammonia (NH3), hydrogen sulfide (H2S), and methane (CH4). Ammonia is one of the most important emissions for evaluating the air quality either in animal buildings or atmospheric environment. In studies of ammonia emission from animal buildings...... emission rate was measured in a wind tunnel under different airflow and ammonium solution temperatures. This investigation provides a general understanding for the influence of velocity, turbulence intensity and temperature on the ammonia emissions. The relationship between ammonia emissions and boundary...... through the air-liquid interface is suggested from vapor-liquid equilibrium properties of ammonia water. Furthermore, the effects of airflow and temperature on ammonia mass transfer coefficient are also analyzed under different concentration boundary conditions determined by various Henry’s law constant...

Glycopyrrolate in toxic exposure to ammonia gas

Directory of Open Access Journals (Sweden)

Bhalla A

2011-01-01

Full Text Available Ammonia (NH 3 is a highly water-soluble, colorless, irritant gas with a unique pungent odor. Liquid ammonia stored under high pressure is still widely used for refrigeration in cold stores used for storing grains. Severe toxicity may occur following accidental exposure. We report an interesting case of accidental exposure to ammonia treated with glycopyrrolate along with other supportive measures.

Acidifier application rate impacts on ammonia emissions from US roaster chicken houses

Science.gov (United States)

Shah, Sanjay B.; Grimes, Jesse L.; Oviedo-Rondón, Edgar O.; Westerman, Philip W.

2014-08-01

Due to its potential environmental and public health impacts, emissions of ammonia (NH3) as well as several other gases from US livestock farms may be regulated. Broiler houses are important sources of NH3 emissions. However, there are no emissions data from roaster (8-12 wk old broilers, ˜4 kg ea.) houses. Producers treat the litter in broiler houses with acidifiers, such as sodium bisulfate (SBS, NaHSO4) to reduce ammonia production and protect bird health. However, there is very little data on the effect of acidifiers, particularly at high application rates on ammonia emissions. The impact of different SBS application rates [High (0.95-1.46 kg m-2, whole house), Medium (0.73 kg m-2, whole house), Low (0.37-0.49 kg m-2, whole house), and Control (0.37-0.49 kg m-2, brood chamber)] on ammonia emissions was evaluated in commercial roaster houses over 22 months spanning eight flocks. Ammonia emission from each fan was measured with an acid scrubber that operated only when the fan operated. Emissions were calculated using >95% measured data with the rest being estimated using robust methods. Exhaust ammonia-N concentrations were inversely correlated with the SBS application rates. Emission rates on animal unit (AU, where 1 AU = 500 kg live-mass) basis (ER, g d-1 AU-1) were reduced by 27, 13, and 5%, respectively, in the High, Medium, and Low treatments vs. the Control treatment (mean: 100 g d-1 AU-1, range: 86-114 g d-1 AU-1). Emission rates for the Control treatment measured in this study on roasters were mostly higher than ERs in the literature. Differences in ERs are not only due to diet, environmental and management conditions, but also due to measurement methods.

The use in grass production of clinoptilolite as an ammonia adsorbent and a nitrogen carrier

Directory of Open Access Journals (Sweden)

Milovanović Jelena

2015-01-01

Full Text Available The clinoptilolite-rich tuff (NZ from Zlatokop deposit (Vranjska Banja, Serbia has been studied as a nitrogen carrier for grass production. Mechanism of binding ammonium cations present in water solutions by NZ has been examined as well as possibility of adsorption of ammonia released in fresh cattle manure during its fermentation. The NH4+ binding from solutions proceeds via an ion-exchange process which follows the pseudo-second-order kinetics. Adsorption isotherms studied at 298-318 K follow the Freundlich isotherm equation. The NZ readily adsorbs ammonia liberated from manure and an addition of 10 wt.% of NZ to manure can preserve up to 90% of ammonia. The potential benefit of this effect has been examined in greenhouse pot experiments with the Italian ryegrass (Lolium multiflorum, var. Macho using three different types of soil (silty, clayey and sandy. The zeta potential measurements show that stability of their colloidal dispersions differs mutually and that addition of the NZ differently affects the stability and nitrogen cycling. All results indicate that NZ can be applied in grass production. [Projekat Ministarstva nauke Republike Srbije, br. 172018 and Norwegian Programme in Higher Education, Research and Development HERD

A non-destructive ammonium detection method as indicator for freshness for packed fish: Application on cod

NARCIS (Netherlands)

Heising, J.K.; Dekker, M.; Bartels, P.V.; Boekel, van M.A.J.S.

2012-01-01

This paper introduces a non-destructive method for monitoring headspace ammonium as an indicator for changes in the freshness status of packed fish. Electrodes in an aqueous phase in the package monitor changes in the concentration of ammonia produced in/on the packed fish and released in the

Ammonia formation by a thiolate-bridged diiron amide complex as a nitrogenase mimic

Science.gov (United States)

Li, Yang; Li, Ying; Wang, Baomin; Luo, Yi; Yang, Dawei; Tong, Peng; Zhao, Jinfeng; Luo, Lun; Zhou, Yuhan; Chen, Si; Cheng, Fang; Qu, Jingping

2013-04-01

Although nitrogenase enzymes routinely convert molecular nitrogen into ammonia under ambient temperature and pressure, this reaction is currently carried out industrially using the Haber-Bosch process, which requires extreme temperatures and pressures to activate dinitrogen. Biological fixation occurs through dinitrogen and reduced NxHy species at multi-iron centres of compounds bearing sulfur ligands, but it is difficult to elucidate the mechanistic details and to obtain stable model intermediate complexes for further investigation. Metal-based synthetic models have been applied to reveal partial details, although most models involve a mononuclear system. Here, we report a diiron complex bridged by a bidentate thiolate ligand that can accommodate HN=NH. Following reductions and protonations, HN=NH is converted to NH3 through pivotal intermediate complexes bridged by N2H3- and NH2- species. Notably, the final ammonia release was effected with water as the proton source. Density functional theory calculations were carried out, and a pathway of biological nitrogen fixation is proposed.

The importance of the ammonia purification process in ammonia-water absorption systems

International Nuclear Information System (INIS)

Fernandez-Seara, Jose; Sieres, Jaime

2006-01-01

Practical experience in working with ammonia-water absorption systems shows that the ammonia purification process is a crucial issue in order to obtain an efficient and reliable system. In this paper, the detrimental effects of the residual water content in the vapour refrigerant are described and quantified based on the system design variables that determine the effectiveness of the purification process. The study has been performed considering a single stage system with a distillation column with complete condensation. The ammonia purification effectiveness of the column is analysed in terms of the efficiencies in the stripping and rectifying sections and the reflux ratio. By varying the efficiencies from 0 to 1, systems with neither the rectifying nor stripping section, with either the rectifying or stripping section, or with both sections can be considered. The impact of the ammonia purification process on the absorption system performance is studied based on the column efficiencies and reflux ratio; and its effects on refrigerant concentration, system COP, system pressures and main system mass flow rates and concentrations are analysed. When the highest efficiency rectifying sections are used a combination of generation temperature and reflux ratio which leads to optimum COP values is found. The analysis covers different operating conditions with air and water cooled systems from refrigeration to air conditioning applications by changing the evaporation temperature. The importance of rectification in each kind of application is evaluated

Chronic toxicity of copper and ammonia to juvenile freshwater mussels (Unionidae)

Science.gov (United States)

Wang, N.; Ingersoll, C.G.; Greer, I.E.; Hardesty, D.K.; Ivey, C.D.; Kunz, J.L.; Brumbaugh, W.G.; Dwyer, F.J.; Roberts, A.D.; Augspurger, T.; Kane, C.M.; Neves, R.J.; Barnhart, M.C.

2007-01-01

The objectives of the present study were to develop methods for conducting chronic toxicity tests with juvenile mussels under flow-through conditions and to determine the chronic toxicity of copper and ammonia to juvenile mussels using these methods. In two feeding tests, two-month-old fatmucket (Lampsilis siliquoidea) and rainbow mussel (Villosa iris) were fed various live algae or nonviable algal mixture for 28 d. The algal mixture was the best food resulting in high survival (???90%) and growth. Multiple copper and ammonia toxicity tests were conducted for 28 d starting with two-month-old mussels. Six toxicity tests using the algal mixture were successfully completed with a control survival of 88 to 100%. Among copper tests with rainbow mussel, fatmucket, and oyster mussel (Epioblasma capsaeformis), chronic value ([ChV], geometric mean of the no-observed-effect concentration and the lowest-observed-effect concentration) ranged from 8.5 to 9.8 ??g Cu/L for survival and from 4.6 to 8.5 ??g Cu/L for growth. Among ammonia tests with rainbow mussel, fatmucket, and wavy-rayed lampmussel (L. fasciola), the ChV ranged from 0.37 to 1.2 mg total ammonia N/L for survival and from 0.37 to 0.67 mg N/L for growth. These ChVs were below the U.S. Environmental Protection Agency 1996 chronic water quality criterion (WQC) for copper (15 ??g/L; hardness 170 mg/L) and 1999 WQC for total ammonia (1.26 mg N/L; pH 8.2 and 20??C). Results indicate that toxicity tests with two-month-old mussels can be conducted for 28 d with >80% control survival; growth was frequently a more sensitive endpoint compared to survival; and the 1996 chronic WQC for copper and the 1999 chronic WQC for total ammonia might not be adequately protective of the mussel species tested. However, a recently revised 2007 chronic WQC for copper based on the biotic ligand model may be more protective in the water tested. ?? 2007 SETAC.

Ammonia Affects Astroglial Proliferation in Culture

Science.gov (United States)

Bodega, Guillermo; Segura, Berta; Ciordia, Sergio; Mena, María del Carmen; López-Fernández, Luis Andrés; García, María Isabel; Trabado, Isabel; Suárez, Isabel

2015-01-01

Primary cultures of rat astroglial cells were exposed to 1, 3 and 5 mM NH4Cl for up to 10 days. Dose- and time-dependent reductions in cell numbers were seen, plus an increase in the proportion of cells in the S phase. The DNA content was reduced in the treated cells, and BrdU incorporation diminished. However, neither ammonia nor ammonia plus glutamine had any effect on DNA polymerase activity. iTRAQ analysis showed that exposure to ammonia induced a significant reduction in histone and heterochromatin protein 1 expression. A reduction in cell viability was also noted. The ammonia-induced reduction of proliferative activity in these cultured astroglial cells seems to be due to a delay in the completion of the S phase provoked by the inhibition of chromatin protein synthesis. PMID:26421615

Ammonia Affects Astroglial Proliferation in Culture.

Directory of Open Access Journals (Sweden)

Guillermo Bodega

Full Text Available Primary cultures of rat astroglial cells were exposed to 1, 3 and 5 mM NH4Cl for up to 10 days. Dose- and time-dependent reductions in cell numbers were seen, plus an increase in the proportion of cells in the S phase. The DNA content was reduced in the treated cells, and BrdU incorporation diminished. However, neither ammonia nor ammonia plus glutamine had any effect on DNA polymerase activity. iTRAQ analysis showed that exposure to ammonia induced a significant reduction in histone and heterochromatin protein 1 expression. A reduction in cell viability was also noted. The ammonia-induced reduction of proliferative activity in these cultured astroglial cells seems to be due to a delay in the completion of the S phase provoked by the inhibition of chromatin protein synthesis.

Ammonium recruitment and ammonia transport by E. coli ammonia channel AmtB

DEFF Research Database (Denmark)

Nygaard, Thomas Pedersen; Rovira, C.; Peters, Günther H.j.

2006-01-01

To investigate substrate recruitment and transport across the Escherichia coli Ammonia transporter B (AmtB) protein, we performed molecular dynamics simulations of the AmtB trimer. We have identified residues important in recruitment of ammonium and intraluminal binding sites selective of ammonium......, which provide a means of cation selectivity. Our results indicate that A162 guides translocation of an extraluminal ammonium into the pore lumen. We propose a mechanism for transporting the intraluminally recruited proton back to periplasm. Our mechanism conforms to net transport of ammonia and can...

Airborne reduced nitrogen: ammonia emissions from agriculture and other sources.

Science.gov (United States)

Anderson, Natalie; Strader, Ross; Davidson, Cliff

2003-06-01

Ammonia is a basic gas and one of the most abundant nitrogen-containing compounds in the atmosphere. When emitted, ammonia reacts with oxides of nitrogen and sulfur to form particles, typically in the fine particle size range. Roughly half of the PM(2.5) mass in eastern United States is ammonium sulfate, according to the US EPA. Results from recent studies of PM(2.5) show that these fine particles are typically deposited deep in the lungs and may lead to increased morbidity and/or mortality. Also, these particles are in the size range that will degrade visibility. Ammonia emission inventories are usually constructed by multiplying an activity level by an experimentally determined emission factor for each source category. Typical sources of ammonia include livestock, fertilizer, soils, forest fires and slash burning, industry, vehicles, the oceans, humans, pets, wild animals, and waste disposal and recycling activities. Livestock is the largest source category in the United States, with waste from livestock responsible for about 3x10(9) kg of ammonia in 1995. Volatilization of ammonia from livestock waste is dependent on many parameters, and thus emission factors are difficult to predict. Despite a seasonal variation in these values, the emission factors for general livestock categories are usually annually averaged in current inventories. Activity levels for livestock are from the USDA Census of Agriculture, which does not give information about animal raising practices such as housing types and grazing times, waste handling systems, and approximate animal slurry spreading times or methods. Ammonia emissions in the United States in 1995 from sources other than livestock are much lower; for example, annual emissions are roughly 8x10(8) kg from fertilizer, 7x10(7) kg from industry, 5x10(7) kg from vehicles and 1x10(8) kg from humans. There is considerable uncertainty in the emissions from soil and vegetation, although this category may also be significant

Designing mixed metal halide ammines for ammonia storage using density functional theory and genetic algorithms.

Science.gov (United States)

Jensen, Peter Bjerre; Lysgaard, Steen; Quaade, Ulrich J; Vegge, Tejs

2014-09-28

Metal halide ammines have great potential as a future, high-density energy carrier in vehicles. So far known materials, e.g. Mg(NH3)6Cl2 and Sr(NH3)8Cl2, are not suitable for automotive, fuel cell applications, because the release of ammonia is a multi-step reaction, requiring too much heat to be supplied, making the total efficiency lower. Here, we apply density functional theory (DFT) calculations to predict new mixed metal halide ammines with improved storage capacities and the ability to release the stored ammonia in one step, at temperatures suitable for system integration with polymer electrolyte membrane fuel cells (PEMFC). We use genetic algorithms (GAs) to search for materials containing up to three different metals (alkaline-earth, 3d and 4d) and two different halides (Cl, Br and I) - almost 27,000 combinations, and have identified novel mixtures, with significantly improved storage capacities. The size of the search space and the chosen fitness function make it possible to verify that the found candidates are the best possible candidates in the search space, proving that the GA implementation is ideal for this kind of computational materials design, requiring calculations on less than two percent of the candidates to identify the global optimum.

Changes of ammonia, urea contents and transaminase activity in the body during aerial exposure and ammonia loading in Chinese loach Paramisgurnus dabryanus.

Science.gov (United States)

Zhang, Yun-Long; Zhang, Hai-Long; Wang, Ling-Yu; Gu, Bei-Yi; Fan, Qi-Xue

2017-04-01

The Paramisgurnus dabryanus was exposed to 30 mmol L -1 NH 4 Cl solution and air to assessing the change of body ammonia and urea contents and the activities of alanine aminotransferase (ALT) and aspartate transaminase (AST). After 48 h of ammonia exposure, ammonia concentration in the plasma, brain, liver and muscle were 3.3-fold, 5.6-fold, 3.5-fold and 4.2-fold, respectively, those of the control values. Plasma, brain, liver and muscle ammonia concentrations increased to 2.2-fold, 3.3-fold, 2.5-fold and 2.9-fold, respectively, those of control values in response to 48 h of aerial exposure. Within the given treatment (ammonia or aerial exposure), there was no change in plasma, brain and liver urea concentrations between exposure durations. The plasma ALT activity was significantly affected by exposure time during aerial exposure, while the liver ALT activity was not affected by ammonia or aerial exposure. Exposure to NH 4 Cl or air had no effect on either plasma or liver AST activity. Our results suggested that P. dabryanus could accumulate quite high level of internal ammonia because of the high ammonia tolerance in its cells and tissues, and NH 3 volatilization would be a possible ammonia detoxification strategy in P. dabryanus. Urea synthesis was not an effective mechanism to deal with environmental or internal ammonia problem. The significant increase of ALT activity in plasma during aerial exposure, indicating that alanine synthesis through certain amino acid catabolism may be subsistent in P. dabryanus.

CADDIS Volume 2. Sources, Stressors and Responses: Ammonia - Simple Conceptual Diagram

Science.gov (United States)

Introduction to the ammonia module, when to list ammonia as a candidate cause, ways to measure ammonia, simple and detailed conceptual diagrams for ammonia, literature reviews and references for the ammonia module.

CADDIS Volume 2. Sources, Stressors and Responses: Ammonia - Detailed Conceptual Diagram

Science.gov (United States)

Introduction to the ammonia module, when to list ammonia as a candidate cause, ways to measure ammonia, simple and detailed conceptual diagrams for ammonia, literature reviews and references for the ammonia module.

Hydrolysis of solid ammonia borane

Energy Technology Data Exchange (ETDEWEB)

Demirci, Umit B.; Miele, Philippe [Universite Lyon 1, CNRS, UMR 5615, Laboratoire des Multimateriaux et Interfaces, 43 boulevard du 11 Novembre 1918, F-69622 Villeurbanne (France)

2010-07-01

Ammonia borane NH{sub 3}BH{sub 3} is a promising hydrogen storage material by virtue of a theoretical gravimetric hydrogen storage capacity (GHSC) of 19.5 wt%. However, stored hydrogen has to be effectively released, one way of recovering this hydrogen being the metal-catalyzed hydrolysis. The present study focuses on CoCl{sub 2}-catalyzed hydrolysis of NH{sub 3}BH{sub 3} with the concern of improving the effective GHSC of the system NH{sub 3}BH{sub 3}-H{sub 2}O. For that, NH{sub 3}BH{sub 3} is stored as a solid and H{sub 2}O is provided in stoichiometric amount. By this way, an effective GHSC of 7.8 wt% has been reached at 25 C. To our knowledge, it is the highest value ever reported. Besides, one of the highest hydrogen generation rates (HGRs, 21 ml(H{sub 2}) min{sup -1}) has been found. In parallel, the increases of the water amount and temperature have been studied and the reaction kinetics has been determined. Finally, it has been observed that some NH{sub 3} release, what is detrimental for a fuel cell. To summarize, high performances in terms of GHSCs and HGRs can be reached with NH{sub 3}BH{sub 3} and since research devoted to this boron hydride is at the beginning we may be confident in making it viable in a near future. (author)

Hydrothermal oxidation of ammonia/organic waste mixtures

International Nuclear Information System (INIS)

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

1997-01-01

Hydrothermal oxidation is a promising new technology for the treatment of radioactive contaminated hazardous organic wastes. Los Alamos National Laboratory is currently evaluating this technology for the U. S. Department of Energy. In this paper, we present experimental results from the study of the hydrothermal oxidation of an ammonia/alcohol/uranium waste mixture. The use of a co-oxidant system consisting of hydrogen peroxide combined with nitrate is discussed. Experiments demonstrate near complete destruction of ammonia and organic compounds at 500 degrees C, 38 MPa, and 50 seconds reaction time. The ammonia and total organic carbon (TOC) concentrations in a waste simulant is reduced from 8,500 mg/L of ammonia and 12,500 mg/L TOC to 30 mg/L ammonia and less than 10 mg/L TOC. The major reaction products are CO 2 , N 2 , and a small amount of N 2 O. Comparison experiments with nitrate and hydrogen peroxide used individually show the advantage of the co-oxidant system

Improving The Efficiency Of Ammonia Electrolysis For Hydrogen Production

Science.gov (United States)

Palaniappan, Ramasamy

Given the abundance of ammonia in domestic and industrial wastes, ammonia electrolysis is a promising technology for remediation and distributed power generation in a clean and safe manner. Efficiency has been identified as one of the key issues that require improvement in order for the technology to enter the market phase. Therefore, this research was performed with the aim of improving the efficiency of hydrogen production by finding alternative materials for the cathode and electrolyte. 1. In the presence of ammonia the activity for hydrogen evolution reaction (HER) followed the trend Rh>Pt>Ru>Ni. The addition of ammonia resulted in lower rates for HER for Pt, Ru, and Ni, which have been attributed to competition from the ammonia adsorption reaction. 2. The addition of ammonia offers insight into the role of metal-hydrogen underpotential deposition (M-Hupd) on HER kinetics. In addition to offering competition via ammonia adsorption it resulted in fewer and weaker M-Hupd bonds for all metals. This finding substantiates the theory that M-Hupd bonds favor HER on Pt electrocatalyst. However, for Rh results suggest that M-Hupd bond may hinder the HER. In addition, the presence of unpaired valence shell electrons is suggested to provide higher activity for HER in the presence of ammonia. 3. Bimetals PtxM1-x (M = Ir, Ru, Rh, and Ni) offered lower overpotentials for HER compared to the unalloyed metals in the presence of ammonia. The activity of HER in the presence of ammonia follows the trend Pt-Ir>Pt-Rh>Pt-Ru>Pt-Ni. The higher activity of HER is attributed to the synergistic effect of the alloy, where ammonia adsorbs onto the more electropositive alloying metal leaving Pt available for Hupd formation and HER to take place. Additionally, this supports the theory that the presence of a higher number of unpaired electrons favors the HER in the presence of ammonia. 4. Potassium polyacrylate (PAA-K) was successfully used as a substitute for aqueous KOH for ammonia

Inventory of LCIA selection methods for assessing toxic releases. Methods and typology report part B

DEFF Research Database (Denmark)

Larsen, Henrik Fred; Birkved, Morten; Hauschild, Michael Zwicky

method(s) in Work package 8 (WP8) of the OMNIITOX project. The selection methods and the other CRS methods are described in detail, a set of evaluation criteria are developed and the methods are evaluated against these criteria. This report (Deliverable 11B (D11B)) gives the results from task 7.1d, 7.1e......This report describes an inventory of Life Cycle Impact Assessment (LCIA) selection methods for assessing toxic releases. It consists of an inventory of current selection methods and other Chemical Ranking and Scoring (CRS) methods assessed to be relevant for the development of (a) new selection...... and 7.1f of WP 7 for selection methods. The other part of D11 (D11A) is reported in another report and deals with characterisation methods. A selection method is a method for prioritising chemical emissions to be included in an LCIA characterisation of toxic releases, i.e. calculating indicator scores...

Study on Release Characteristics and Recovery of Nitrogen and Phosphorus during the Anaerobic Fermentation of Excess Sludge

Science.gov (United States)

Qin, Yuqian; Hu, Shulong

2018-01-01

Ammonia nitrogen and phosphate are produced from activated excess sludge under anaerobic conditions,and will cause eutrophication upon release to the environment. A study of sludge from a eutrophication was carried out, to obtain knowledge of the nitrogen and phosphorus release patterns of the excess sludge during anaerobic fermentation and the recycling efficiency of both nitrogen and phosphorus, by adding magnesium salt and alkali solution to the supernatant liquors. The results showed that the concentration of ammonia nitrogen and phosphate of the supernatant liquors continued to increase during the process of anaerobic digestion, and both reached a maximum in 12 days, at 41.56mg / L and 47.02 mg / L respectively. By adding magnesium salt to the supernatant with c(Mg): c(P) = 1.1:1, adjusting pH value to 9.0 ∼ 9.5, phosphorus recovery rate reached up to 95.0%, while the recovery rate of ammonia was 47.4%, resulting in the formation of a sediment of magnesium ammonium phosphate, or MAP, which may he used as a high-quality fertilizer.

Potential for visible plume formation at a coal-fired boiler using ammonia injection for non-catalytic NOx control

International Nuclear Information System (INIS)

Hess, T.

1993-01-01

Circulating fluidized bed boilers utilizing ammonia injection for non-catalytic NO x reduction have been highly successful in reducing NO x emissions to very low levels. However, one limitation on this technology is the potential for the formation of visible plumes. One plant, with uncontrolled NO x of about 190 ppm, reduces NO x concentrations to the 20-25 ppm range by injecting ammonia in the boiler's cyclones. However, infrequent, short-lived, white, detached plumes have been noted extending for short distances downwind of the stack. Because unreacted ammonia is present in the flue gas along with HCl from coal combustion, the formation of solid NH 4 Cl in the atmosphere was suspected to be the most likely cause of the visible plume. Simple thermodynamic calculations predict the formation of solid ammonium chloride very soon after the flue gas mixes with cooler ambient air and plume optical density calculations are in reasonable agreement with observed plume density. Stack testing and other tests have been conducted during both plume and non-plume events to confirm that NH 4 Cl formation is the most likely cause of the capacity. As presented in this paper, the test data and theoretical calculations indicate that a visible plume may be expected when as little as 5 ppm of ammonia and HCl are present in the flue gas, depending on observation conditions. Analyses of fuel samples taken during stack tests show about 40% of the chlorine in the low chloride coal fired, typically less than 0.04%, is released from the stack as HCl. Ammonia slip is somewhat variable depending on combustion conditions in the boiler and the temperature at the ammonia injection points

The effect of ammonia intercalation on the superconducting ...

African Journals Online (AJOL)

A theoretical investigation of the electronic properties of the relatively high-Tc alkali-metal doped superconducting fullerides when they are further exposed to ammonia molecules as dopants is presented. Our numerical method relies on a group theoretical technique for the formation of molecular orbitals (MO's) for the solid ...

Extracellular ammonia at sites of pulmonary infection with Coccidioides posadasii contributes to severity of the respiratory disease.

Science.gov (United States)

Wise, Hua Zhang; Hung, Chiung-Yu; Whiston, Emily; Taylor, John W; Cole, Garry T

2013-01-01

Coccidioides is the causative agent of a potentially life-threatening respiratory disease of humans. A feature of this mycosis is that pH measurements of the microenvironment of pulmonary abscesses are consistently alkaline due to ammonia production during the parasitic cycle. We previously showed that enzymatically active urease is partly responsible for elevated concentrations of extracellular ammonia at sites of lung infection and contributes to both localized host tissue damage and exacerbation of the respiratory disease in BALB/c mice. Disruption of the urease gene (URE) of Coccidioides posadasii only partially reduced the amount of ammonia detected during in vitro growth of the parasitic phase, suggesting that other ammonia-producing pathways exist that may also contribute to the virulence of this pathogen. Ureidoglycolate hydrolase (Ugh) expressed by bacteria, fungi and higher plants catalyzes the hydrolysis of ureidoglycolate to yield glyoxylate and the release CO2 and ammonia. This enzymatic pathway is absent in mice and humans. Ureidoglycolate hydrolase gene deletions were conducted in a wild type (WT) isolate of C. posadasii as well as the previously generated Δure knock-out strain. Restorations of UGH in the mutant stains were performed to generate and evaluate the respective revertants. The double mutant revealed a marked decrease in the amount of extracellular ammonia without loss of reproductive competence in vitro compared to both the WT and Δure parental strains. BALB/c mice challenged intranasally with the Δugh/Δure mutant showed 90% survival after 30 days, decreased fungal burden, and well-organized pulmonary granulomas. We conclude that loss of both Ugh and Ure activity significantly reduced the virulence of this fungal pathogen. Copyright © 2013 Elsevier Ltd. All rights reserved.

Treatment of ammonia in waste air using packed column coupling with chemical reaction

Directory of Open Access Journals (Sweden)

Thepchai, R.

2007-05-01

Full Text Available Ammonia is a common chemical used in various industries. Emission of air contaminated with ammonia to the atmosphere without any treatment causes several effects on human health and environment.A high efficiency method for ammonia removal from waste air is then necessary. In this research, an absorption coupling with chemical reaction was investigated for ammonia removal from waste air using a packedcolumn. The packed column of 10 cm diameter and 200 cm height was packed with 1.4x1.4 cm Raschig rings. Three liquids including water, NaOCl and H2SO4 solution were used as an absorbent for the investigation.The objectives of this research were to determine a suitable absorbent and the optimum condition for ammonia removal from waste air. The packed column was operated at room temperature and atmosphericpressure. The tested conditions were as follows: the gas to liquid ratio (G:L ratio was 35-90 m3 gas/m3 liquid, the inlet concentration of ammonia was 150-500 ppm and the air flow rate was 18 m3/h. The results showedthat the ammonia removal efficiency depends on type of the absorbent and the operating condition. The efficiencies increased with decreasing of G:L ratio and with increasing absorbent concentration. They were70%, 80-92%, and 95-100% for pure water, sodium hypochlorite solution and sulphuric acid solution, respectively. The efficiency decreased with time when water was used as an absorbent while it was almostconstant when NaOCl and H2SO4 solution were applied. The ammonia removal efficiency when using H2SO4 as the absorbent was not dependent on G:L ratio and inlet ammonia concentration, in the range used in thisinvestigation. Since H2SO4 solution gave the highest removal efficiency and can reduce ammonia concentration in waste air to levels which meet the TLV-TWA standard, it is recommended as an absorbent solution forammonia removal from waste air.

POSTEROLATERAL DEFECT OF THE NORMAL HUMAN HEART INVESTIGATED WITH NITROGEN-13-AMMONIA AND DYNAMIC PET

NARCIS (Netherlands)

DEJONG, RM; BLANKSMA, PK; WILLEMSEN, ATM; ANTHONIO, RL; MEEDER, JG; PRUIM, J; VAALBURG, W; LIE, KI

The posterolateral defect is a common artifact seen when static N-13-ammonia imaging with PET is used to assess myocardial perfusion. The aim of this study was to compare dynamic and static N-13-ammonia PET and to obtain more insight into the cause of the posterolateral defect. Methods: Dynamic

Steady Modeling for an Ammonia Synthesis Reactor Based on a Novel CDEAS-LS-SVM Model

Directory of Open Access Journals (Sweden)

Zhuoqian Liu

2014-01-01

Full Text Available A steady-state mathematical model is built in order to represent plant behavior under stationary operating conditions. A novel modeling using LS-SVR based on Cultural Differential Evolution with Ant Search is proposed. LS-SVM is adopted to establish the model of the net value of ammonia. The modeling method has fast convergence speed and good global adaptability for identification of the ammonia synthesis process. The LS-SVR model was established using the above-mentioned method. Simulation results verify the validity of the method.

Power-to-ammonia: rethinking the role of ammonia – from a value product to a flexible energy carrier (FlexNH3)

NARCIS (Netherlands)

Bennani, Yasmina; Perl, Andras; Patil, Anish; van Someren, Christian; Heijne, Leo; van Steenis, Machiel

2016-01-01

This report focuses on the feasibility of the power-to-ammonia concept. Power-to-ammonia uses produced excess renewable electricity to electrolyze water, and then to react the obtained hydrogen with nitrogen, which is obtained through air separation, to produce ammonia. This process may be used as a

Theoretical investigation of reactions between ammonia and precursors from the ozonolysis of ethene

Energy Technology Data Exchange (ETDEWEB)

Jorgensen, Solvejg, E-mail: solvejg@kemi.ku.dk [Copenhagen Center of Atmospheric Research, Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen O (Denmark); Gross, Allan, E-mail: agr@dmi.dk [Research Department, Danish Meteorological Institute, Lyngbyvej 100, DK-2100 Copenhagen O (Denmark)

2009-07-30

The reaction mechanisms between ammonia and two secondary organic aerosol (SOA) precursors from ozonolysis of alkenes - namely the secondary ozonide (SOZ) and hydroxyl substituted ester (HSE) have been investigated using quantum mechanics calculations. For the reaction between ammonia and SOZ, three reaction channels were found (i) an aldehyde, a hydrogen peroxide and an imine, (ii) two aldehydes and a hydroxylamine, (iii) a hydroxyalkyl hydroperoxide and an imine. For the reaction involving the HSE the reaction products are an aldehyde, carboxylic acid and ammonia. The B3LYP method with 6-311++G(2d,2p) basis set was employed for the geometry optimisation of the stationary points. Gaussian 2 and Gaussian 3 levels of theory have been used to optimise and refine the energy. From an energetic point of view, it is concluded that the reaction between ammonia and HSE is in favour compared to the one with the SOZ.

SiO2 sol-gel films after ammonia and heat two-step treatments

International Nuclear Information System (INIS)

Zhang Chunlai; Wang Biyi; Tian Dongbin; Yin Wei; Jiang Xiaodong; Yuan Xiaodong; Yan Lianghong; Zhang Hongliang; Zhao Songnan; Lv Haibing

2008-01-01

SiO 2 thin films were deposited using tetraethoxylsilane as precursor, ammonia as catalyst on K9 glass by sol-gel method. These films were post-treated by ammonia and heat. The properties of the coatings were characterized by ellipsometer, UV-vis spectrophotometry, FTIR-spectroscopy, scanning probe microscope and contact angle measurement apparatus. The resuits indicate that the thickness of the films with ammonia and heat treatment tend to decrease. Both the refractive index and water contact angle increase after ammonia treatment. However, they both decrease after heat treatment. The former increases by 0.236 for the first step, then decreases by 0.202 for the second. The latter increases to 58.92 degree, then decreases to 38.07 degree. The transmittance of the coatings turn to be better and continuously shift to short wave by UV-vis spectrophotometry. The surface becomes smoother by AFM after the two-step treatment. (authors)

System and method for controlling an engine based on ammonia storage in multiple selective catalytic reduction catalysts

Science.gov (United States)

Sun, MIn; Perry, Kevin L.

2015-11-20

A system according to the principles of the present disclosure includes a storage estimation module and an air/fuel ratio control module. The storage estimation module estimates a first amount of ammonia stored in a first selective catalytic reduction (SCR) catalyst and estimates a second amount of ammonia stored in a second SCR catalyst. The air/fuel ratio control module controls an air/fuel ratio of an engine based on the first amount, the second amount, and a temperature of a substrate disposed in the second SCR catalyst.

Nitrogen metabolism and kinetics of ammonia-oxidizing archaea.

Science.gov (United States)

Martens-Habbena, Willm; Stahl, David A

2011-01-01

The discovery of ammonia-oxidizing mesophilic and thermophilic Group I archaea changed the century-old paradigm that aerobic ammonia oxidation is solely mediated by two small clades of Beta- and Gammaproteobacteria. Group I archaea are extremely diverse and ubiquitous in marine and terrestrial environments, accounting for 20-30% of the microbial plankton in the global oceans. Recent studies indicated that many of these organisms carry putative ammonia monooxygenase genes and are more abundant than ammonia-oxidizing bacteria in most natural environments suggesting a potentially significant role in the nitrogen cycle. The isolation of Nitrosopumilus maritimus strain SCM1 provided the first direct evidence that Group I archaea indeed gain energy from ammonia oxidation. To characterize the physiology of this archaeal nitrifier, we developed a respirometry setup particularly suited for activity measurements in dilute microbial cultures with extremely low oxygen uptake rates. Here, we describe the setup and review the kinetic experiments conducted with N. maritimus and other nitrifying microorganisms. These experiments demonstrated that N. maritimus is adapted to grow on ammonia concentrations found in oligotrophic open ocean environments, far below the survival threshold of ammonia-oxidizing bacteria. The described setup and experimental procedures should facilitate physiological studies on other nitrifying archaea and oligotrophic microorganisms in general. Copyright © 2011 Elsevier Inc. All rights reserved.

Study on adsorption mechanism of ammonia nitrogen in wastewater by natural heulandite

Directory of Open Access Journals (Sweden)

Xuekai JIN

2018-02-01

Full Text Available In order to explore the adsorption mechanism and optimal regeneration method of natural heulandite to high ammonia nitrogen wastewater, the natural heulandite from Hebei Province is selected as the research object. The adsorption kinetics, adsorption isotherms and adsorption thermodynamics are studied by single factor test. The results show that the adsorption process of ammonia nitrogen on heulandite with particle size range of 50~600 μm complies with the quasi-second order kinetic equation with ammonia nitrogen concentration of 500 mg/L at temperature of 25 ℃. Particle diffusion and liquid film diffusion are the dominated process of the adsorption. The adsorption capacity of heulandite is 7.81 mg/g at temperature of 45 ℃. The adsorption isotherm of ammonia nitrogen on the experimental heulandite is fitted well with Freundlich model. Gibbs free energy ΔG is calculated to be less than zero, indicating that the adsorption of ammonia nitrogen on the experimental heulandite is a spontaneous endothermic reaction. Additionally, the adsorption capacity of heulandite increases with appropriate increaseing in temperature. The optimal regeneration solvent of the saturated heulandite is 0.1 mol/L of NaCl, with which the desorption rate increases to 79%, and the times of elution and regeneration are more than 5. The results of this study can improve the economic benefits and environmental value of heulandite in the treatment of ammonia nitrogen wastewater. It can be seen that heulandite in the industrial wastewater treatment has broad prospects for application.

The diagnostic value of 13N-ammonia PET in ischemic cerebrovascular disorders

International Nuclear Information System (INIS)

Qiao Shuixian; Tang Anwu; Wang Lijuan; Liu Xintong; Yuan Yanbo; Chen Liguang; Luo Yaowu; Zhang Xiangsong; Wang Shuxia; Liu Bin; Xu Weiping

2002-01-01

Objective: To evaluate the feasibility of 13 N-ammonia PET in diagnosing ischemic cerebrovascular disorders. Methods: A total of 25 subjects were investigated. Five healthy volunteers served as normal control. Twenty patients included 13 with transient ischemic attack (TIA), 6 with brain infarction and 1 with moyamoya disease. 740-925 MBq of 13 N-ammonia was injected intravenously, 3-5 min later, PET imaging was performed with T + E 2D acquisition with Siemens ECAT EXACT HR + PET scanner. Image analysis was done by visual and semiquantitative estimating. Standardized uptake value (SUV) was measured in mirror regions of cerebrum with autocopy methods. Nine patients underwent drug stress with oral acetazolamide (ACZ). Images were compared before and after oral ACZ intervention. Results: Physiological brain uptake with SUV ratio of 0.99 +- 0.15 (n=5, left/right) was observed in healthy volunteers. L/N 13 N-ammonia as radioactive tracer was a safe and noninvasive, sensitive and accurate functional imaging modality for brain perfusion. The oral ACZ stress is a safe, simple and reliable diagnostic method for ischemic cerebrovascular disorders. It is of important uses in detecting the potential reserve of cerebral blood flow

The origin of mouth-exhaled ammonia.

Science.gov (United States)

Chen, W; Metsälä, M; Vaittinen, O; Halonen, L

2014-09-01

It is known that the oral cavity is a production site for mouth-exhaled NH3. However, the mechanism of NH3 production in the oral cavity has been unclear. Since bacterial urease in the oral cavity has been found to produce ammonia from oral fluid urea, we hypothesize that oral fluid urea is the origin of mouth-exhaled NH3. Our results show that under certain conditions a strong correlation exists between oral fluid urea and oral fluid ammonia (NH4(+)+NH3) (rs = 0.77, p oral fluid NH3 and mouth-exhaled NH3 (rs = 0.81, p oral fluid pH. Bacterial urease catalyses the hydrolysis of oral fluid urea to ammonia (NH4(+)+NH3). Oral fluid ammonia (NH4(+)+NH3) and pH determine the concentration of oral fluid NH3, which evaporates from oral fluid into gas phase and turns to mouth-exhaled NH3.

15N-enrichments of ammonia and glutamine in blood after infusion of 15N-ammonia in chickens fed low or high protein diet

International Nuclear Information System (INIS)

Karasawa, Yutaka; Koh, Katsuki

1985-01-01

In this experment, the blood ammonia and glutamine amide came from infused ammonia were determined when N-15 labeled ammonium acetate was intraportally infused into the chickens fed 5 or 20 % protein diet. The data obtained indicated that the infused ammonia was taken into blood glutamine amide, and also accumulated in blood as it is, in both dietary groups. 10 to 12 months old White Leghorn male birds were used. The experimental diet was fed once a day for 5 days to the birds weighting about 1.2 kg by 35 g per kg body weight. The experimental diet was consumed within 40 min in all cases. Cardiac and portal catheterization were performed for blood collection and ammonia infusion, respectively. After finishing the infusion, blood samples were taken to analyze the ammonia and glutamine contents and their N-15 enrichment. Statistical difference was not observed in the appearance of N-15 in ammonia and glutamine amide between two dietary groups. The N-15 enrichment in blood ammonia and the amide of plasma glutamine, and the calculated exogenous nitrogen in the ammonia and glutamine amide tended to be more in the 5 % protein diet group than the other. (Kako, I.)

Growth of ammonia-oxidizing archaea and bacteria in cattle manure compost under various temperatures and ammonia concentrations.

Science.gov (United States)

Oishi, Ryu; Tada, Chika; Asano, Ryoki; Yamamoto, Nozomi; Suyama, Yoshihisa; Nakai, Yutaka

2012-05-01

A recent study showed that ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) coexist in the process of cattle manure composting. To investigate their physiological characteristics, liquid cultures seeded with fermenting cattle manure compost were incubated at various temperatures (37°C, 46°C, or 60°C) and ammonium concentrations (0.5, 1, 4, or 10 mM NH (4) (+) -N). The growth rates of the AOB and AOA were monitored using real-time polymerase chain reaction analysis targeting the bacterial and archaeal ammonia monooxygenase subunit A genes. AOB grew at 37°C and 4 or 10 mM NH (4) (+) -N, whereas AOA grew at 46°C and 10 mM NH (4) (+) -N. Incubation with allylthiourea indicated that the AOB and AOA grew by oxidizing ammonia. Denaturing gradient gel electrophoresis and subsequent sequencing analyses revealed that a bacterium related to Nitrosomonas halophila and an archaeon related to Candidatus Nitrososphaera gargensis were the predominant AOB and AOA, respectively, in the seed compost and in cultures after incubation. This is the first report to demonstrate that the predominant AOA in cattle manure compost can grow and can probably oxidize ammonia under moderately thermophilic conditions.

Ammonia as a respiratory gas in water and air-breathing fishes.

Science.gov (United States)

Randall, David J; Ip, Yuen K

2006-11-01

Ammonia is produced in the liver and excreted as NH(3) by diffusion across the gills. Elevated ammonia results in an increase in gill ventilation, perhaps via stimulation of gill oxygen chemo-receptors. Acidification of the water around the fish by carbon dioxide and acid excretion enhances ammonia excretion and constitutes "environmental ammonia detoxification". Fish have difficulties in excreting ammonia in alkaline water or high concentrations of environmental ammonia, or when out of water. The mudskipper, Periphthalmodon schlosseri, is capable of active NH(4)(+) transport, maintaining low internal levels of ammonia. To prevent a back flux of NH(3), these air-breathing fish can increase gill acid excretion and reduce the membrane NH(3) permeability by modifying the phospholipid and cholesterol compositions of their skin. Several air-breathing fish species can excrete ammonia into air through NH(3) volatilization. Some fish detoxify ammonia to glutamine or urea. The brains of some fish can tolerate much higher levels of ammonia than other animals. Studies of these fish may offer insights into the nature of ammonia toxicity in general.

Operational experience in mitigating flammable gas releases from Hanford Site Tank 241-SY-101

International Nuclear Information System (INIS)

Lentsch, J.W.; Babad, H.; Kirch, N.W.

1995-01-01

Flammable gases consisting of hydrogen, nitrous oxide, ammonia, and methane are periodically released from Hanford Site waste tank 241-SY-101 at concentrations above the flammable limit. A large mixer pump installed in the tank in 1993 has effectively mitigated this problem by continuously releasing small amounts of the flammable gases at the rate they are generated. Tank 241-SY-101 is also equipped with multiple high-sensitivity gas monitoring systems and level detection systems to measure the quantity of gas that is retained in and released from the waste

Role of In Vitro Release Methods in Liposomal Formulation Development: Challenges and Regulatory Perspective.

Science.gov (United States)

Solomon, Deepak; Gupta, Nilesh; Mulla, Nihal S; Shukla, Snehal; Guerrero, Yadir A; Gupta, Vivek

2017-11-01

In the past few years, measurement of drug release from pharmaceutical dosage forms has been a focus of extensive research because the release profile obtained in vitro can give an indication of the drug's performance in vivo. Currently, there are no compendial in vitro release methods designed for liposomes owing to a range of experimental challenges, which has created a major hurdle for both development and regulatory acceptance of liposome-based drug products. In this paper, we review the current techniques that are most often used to assess in vitro drug release from liposomal products; these include the membrane diffusion techniques (dialysis, reverse dialysis, fractional dialysis, and microdialysis), the sample-and-separate approach, the in situ method, the continuous flow, and the modified United States Pharmacopeia methods (USP I and USP IV). We discuss the principles behind each of the methods and the criteria that assist in choosing the most appropriate method for studying drug release from a liposomal formulation. Also, we have included information concerning the current regulatory requirements for liposomal drug products in the United States and in Europe. In light of increasing costs of preclinical and clinical trials, applying a reliable in vitro release method could serve as a proxy to expensive in vivo bioavailability studies. Graphical Abstract Appropriate in-vitro drug release test from liposomal products is important to predict the in-vivo performance.

Atmospheric behaviour of ammonia and ammonium

NARCIS (Netherlands)

Asman, W.A.H.

1987-01-01

1.4.1 Scope of this thesis

A few models for ammonia and ammonium exist. Russell et al. (1983) made a multi-layer Lagrangian transport model describing the transport and formation of ammonium nitrate aerosol for California. They did not take reactions of ammonia and sulphuric acid

Heat release from wood wall assemblies using oxygen consumption method

Science.gov (United States)

Hao C. Tran; Robert E. White

1990-01-01

The concept of heat release rate is gaining acceptance in the evaluation of fire performance of materials and assemblies. However, this concept has not been incorporated into fire endurance testing such as the ASTM E-119 test method. Heat release rate of assemblies can be useful in determining the time at which the assemblies start to contribute to the controlled fire...

46 CFR 151.50-32 - Ammonia, anhydrous.

Science.gov (United States)

2010-10-01

... enclosed anhydrous ammonia tanks complies with the following chemical and physical properties: (1) Boiling... requirements of § 151.50-30 for compressed gases are also applicable to the shipment of anhydrous ammonia...

A high-performance liquid chromatography method for the serotonin release assay is equivalent to the radioactive method.

Science.gov (United States)

Sono-Koree, N K; Crist, R A; Frank, E L; Rodgers, G M; Smock, K J

2016-02-01

The serotonin release assay (SRA) is considered the gold standard laboratory test for heparin-induced thrombocytopenia (HIT). The historic SRA method uses platelets loaded with radiolabeled serotonin to evaluate platelet activation by HIT immune complexes. However, a nonradioactive method is desirable. We report the performance characteristics of a high-performance liquid chromatography (HPLC) SRA method. We validated the performance characteristics of an HPLC-SRA method, including correlation with a reference laboratory using the radioactive method. Serotonin released from reagent platelets was quantified by HPLC using fluorescent detection. Results were expressed as % release and classified as positive, negative, or indeterminate based on previously published cutoffs. Serum samples from 250 subjects with suspected HIT were tested in the HPLC-SRA and with the radioactive method. Concordant classifications were observed in 230 samples (92%). Sera from 41 healthy individuals tested negative. Between-run imprecision studies showed standard deviation of performance characteristics, equivalent to the historic radioactive method, but avoids the complexities of working with radioactivity. © 2015 John Wiley & Sons Ltd.

Effects of different fertilizers on the abundance and community structure of ammonia oxidizers in a yellow clay soil.

Science.gov (United States)

Yao, Huaiying; Huang, Sha; Qiu, Qiongfen; Li, Yaying; Wu, Lianghuan; Mi, Wenhai; Dai, Feng

2016-08-01

Yellow clay paddy soil (Oxisols) is a typical soil with low productivity in southern China. Nitrification inhibitors and slow release fertilizers have been used to improve nitrogen fertilizer utilization and reduce environmental impaction of the paddy soil. However, their effects on ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) in paddy soil have rarely been investigated. In the present work, we compared the influences of several slow release fertilizers and nitrification inhibitors on the community structure and activities of the ammonia oxidizers in yellow clay soil. The abundances and community compositions of AOA and AOB were determined with qPCR, terminal restriction fragment length polymorphism (T-RFLP), and clone library approaches. Our results indicated that the potential nitrification rate (PNR) of the soil was significantly related to the abundances of both AOA and AOB. Nitrogen fertilizer application stimulated the growth of AOA and AOB, and the combinations of nitrapyrin with urea (NPU) and urea-formaldehyde (UF) inhibited the growth of AOA and AOB, respectively. Compared with other treatments, the applications of NPU and UF also led to significant shifts in the community compositions of AOA and AOB, respectively. NPU showed an inhibitory effect on AOA T-RF 166 bp that belonged to Nitrosotalea. UF had a negative effect on AOB T-RF 62 bp that was assigned to Nitrosospira. These results suggested that NPU inhibited PNR and increased nitrogen use efficiency (NUE) by inhibiting the growth of AOA and altering AOA community. UF showed no effect on NUE but decreased AOB abundance and shifted AOB community.

Gas sensors for ammonia detection based on polyaniline-coated multi-wall carbon nanotubes

International Nuclear Information System (INIS)

He Lifang; Jia Yong; Meng Fanli; Li Minqiang; Liu Jinhuai

2009-01-01

Polyaniline-coated multi-wall carbon nanotubes (PANI-coated MWNTs) were prepared by in situ polymerization method. Field emission scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, and thermogravimetric analysis were used to characterize the as-prepared PANI-coated MWNTs. Obtained results indicated that PANI was uniformly coated on MWNTs, and the thickness of the coatings can be controlled by changing the weight ratios of aniline monomer and MWNTs in the polymerization process. Sensors were fabricated by spin-coating onto pre-patterned electrodes, and ammonia gas sensing properties of the as-prepared PANI-coated MWNTs were studied. The results showed a good response and reproducibility towards ammonia at room temperature. In addition, PANI-coated MWNTs exhibited a linear response to ammonia in the range of 0.2-15 ppm. The effects of the thickness of PANI coatings on the gas sensing properties were also investigated in detail. The results suggest a potential application of PANI-coated MWNTs in gas sensor for detecting ammonia.

Green synthesis of biopolymer-silver nanoparticle nanocomposite: an optical sensor for ammonia detection.

Science.gov (United States)

Pandey, Sadanand; Goswami, Gopal K; Nanda, Karuna K

2012-11-01

Biopolymer used for the production of nanoparticles (NPs) has attracted increasing attention. In the presence article we use aqueous solution of polysaccharide Cyamopsis tetragonaloba commonly known as guar gum (GG), from plants. GG acts as reductive preparation of silver nanoparticles which are found to be powder X-ray diffraction technique. Aqueous ammonia sensing study of polymer/silver nanoparticles nanocomposite (GG/AgNPs NC) was performed by optical method based on surface plasmon resonance (SPR). The performances of optical sensor were investigated which provide the excellent result. The response time of 2-3 s and the detection limit of ammonia solution, 1 ppm were found at room temperature. Thus, in future this room temperature optical ammonia sensor can be used for clinical and medical diagnosis for detecting low ammonia level in biological fluids, such as plasma, sweat, saliva, cerebrospinal liquid or biological samples in general for various biomedical applications in human. Copyright © 2012 Elsevier B.V. All rights reserved.

Carboxymethylguargum-silver nanocomposite: green synthesis, characterization and an optical sensor for ammonia detection

International Nuclear Information System (INIS)

Gupta, Anek Pal; Verma, Devendra Kumar

2014-01-01

This work describes the preparation of new carboxymethyl guar gum-silver nanocomposite (CMGG/Ag NC) by green synthesis method. For this carboxymethyl guar gum was used as a reducing agent as well as stabilizer. The silver nanoparticles obtained were characterized by field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), UV–vis spectroscopy, Fourier transform infrared (FTIR) and energy dispersive x-ray analysis (EDX). The average size of the silver nanoparticles was found of ∼6 nm. Thus, the obtained CMGG/AgNPs NC was examined for optical sensing property for detection of ammonia in aqueous medium. The response time and the detection limit of ammonia in aqueous solution were detected at room temperature. It was concluded that in the future, at this room temperature optical ammonia sensor may be used for medical diagnosis and clinically for detecting low ammonia level (up to 1 ppm) in biological samples for various biomedical applications. (paper)

Thiourea-treated graphene aerogel as a highly selective gas sensor for sensing of trace level of ammonia

Energy Technology Data Exchange (ETDEWEB)

Alizadeh, Taher, E-mail: talizadeh@ut.ac.ir [Department of Analytical Chemistry, Faculty of Chemistry, University College of Science, University of Tehran, P.O. Box 14155-6455, Tehran (Iran, Islamic Republic of); Ahmadian, Farzaneh [Department of Applied Chemistry, Faculty of Science, University of Mohaghegh Ardabili, Daneshgah Street, P.B179, 56199-11367 Ardabil (Iran, Islamic Republic of)

2015-10-15

As a result of this study, a new and simple method was proposed for the fabrication of an ultra sensitive, robust and reversible ammonia gas sensor. The sensing mechanism was based upon the change in electrical resistance of a graphene aerogel as a result of sensor exposing to ammonia. Three-dimensional graphene hydrogel was first synthesized via hydrothermal method in the absence or presence of various amounts of thiourea. The obtained material was heated to obtain aerogel and then it was used as ammonia gas sensor. The materials obtained were characterized using different techniques such as Fourier transform infrared spectroscopy (FT-IR), thermal gravimetric analysis (TGA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). The thiourea-treated graphene aerogel was more porous (389 m{sup 2} g{sup −1}) and thermally unstable and exhibited higher sensitivity, shorter response time and better selectivity toward ammonia gas, compared to the aerogel produced in the absence of thiourea. Thiourea amount, involved in the hydrogel synthesis step, was found to be highly effective factor in the sensing properties of finally obtained aerogel. The sensor response time to ammonia was short (100 s) and completely reversible (recovery time of about 500 s) in ambient temperature. The sensor response to ammonia was linear between 0.02 and 85 ppm and its detection limit was found to be 10 ppb (3S/N). - Highlights: • An ammonia gas sensor with ppb level determination capability was proposed. • A new procedure has been introduced for gas sensor fabrication by graphene hydrogel. • Thiourea-treated graphene aerogel was used as excellent ammonia gas sensor.

Heat-equilibrium low-temperature plasma decay in synthesis of ammonia via transient components N2H6

International Nuclear Information System (INIS)

Cao Guobin; Song Youqun; Chen Qing; Zhou Qiulan; Cao Yun; Wang Chunhe

2001-01-01

The author introduced a new method of heat-equilibrium low-temperature plasma in ammonia synthesis and a technique of continuous real-time inlet sampling mass-spectrometry to detect the reaction channel and step of the decay of transient component N 2 H 6 into ammonia. The experimental results indicated that in the process of ammonia synthesis by discharge of N 2 and H 2 mixture, the transient component N 2 H 6 is a necessary step

Impaired cerebral microcirculation induced by ammonium chloride in rats is due to cortical adenosine release

DEFF Research Database (Denmark)

Bjerring, Peter Nissen; Bjerrum, Esben Jannik; Larsen, Fin Stolze

2018-01-01

BACKGROUND: Liver failure results in hyperammonaemia, impaired regulation of cerebral microcirculation, encephalopathy and death. However, the key mediator that alters cerebral microcirculation remains unidentified. In this study we show that topical ammonium significantly increases periarteriolar......: In patients with liver failure disturbances in the brain function is caused in part by ammonia toxicity. In our project we have studied how ammonia, through adenosine release, affects the blood flow in the brain of rats. In our experimental model we demonstrated that the detrimental effect of ammonia on blood...... flow regulation was counteracted by blocking the adenosine receptors in the brain. With this observation we have identified a novel potential treatment target. If we can confirm our findings in a future clinical study it might help patients suffering from liver failure and the severe condition called...

Ammonia modification for flotation separation of polycarbonate and polystyrene waste plastics.

Science.gov (United States)

Wang, Chong-Qing; Wang, Hui; Gu, Guo-Hua; Lin, Qing-Quan; Zhang, Ling-Ling; Huang, Luo-Luo; Zhao, Jun-Yao

2016-05-01

A promising method, ammonia modification, was developed for flotation separation of polycarbonate (PC) and polystyrene (PS) waste plastics. Ammonia modification has little effect on flotation behavior of PS, while it changes significantly that of PC. The PC recovery in the floated product drops from 100% to 3.17% when modification time is 13min and then rises to 100% after longer modification. The mechanism of ammonia modification was studied by contact angle, and Fourier transform infrared (FT-IR) and X-ray photoelectron spectroscopy (XPS) measurements. Contact angle of PC indicates the decline of PC recovery in the floated product is ascribed to an increase in surface wettability. FT-IR and XPS spectra suggest that ammonia modification causes chemical reactions occurred on PC surface. Flotation behavior of ammonia-modified PC and PS was investigated with respect to flotation time, frother concentration and particle sizes. Flotation separation of PC and PS waste plastics was conducted based on the flotation behavior of single plastic. PC and PS mixtures with different particle sizes are separated efficiently, implying that the technology possesses superior applicability to particle sizes of plastics. The purity of PS and PC is up to 99.53% and 98.21%, respectively, and the recovery of PS and PC is larger than 92.06%. A reliable, cheap and effective process is proposed for separation of PC and PS waste plastics. Copyright © 2016 Elsevier Ltd. All rights reserved.

46 CFR 98.25-5 - How anhydrous ammonia may be carried.

Science.gov (United States)

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false How anhydrous ammonia may be carried. 98.25-5 Section 98... Anhydrous Ammonia in Bulk § 98.25-5 How anhydrous ammonia may be carried. (a) Anhydrous ammonia shall be..., except as otherwise provided in paragraph (b) of this section. (b) When anhydrous ammonia is to be...

Ammonia-water Rankine cycle

International Nuclear Information System (INIS)

Bo Hanliang; Ma Changwen; Wu Shaorong

1997-01-01

On characteristics of heating source and cooling source in nuclear heating reactor cooperation, the authors advance a new kind of power cycle in which a multicomponent mixture as the work fluid, ammonia-water Rankine cycle, describe its running principle, and compare it with steam Rankine cycle in the same situation. The result is that: the new kind of power cycle, ammonia-water Rankine cycle has higher electricity efficiency; it suits for the situation of heating source and cooling source which offered by nuclear heating reactor cooperation. For low temperature heating source, it maybe has a widely application

Method and apparatus for releasably connecting first and second objects

Science.gov (United States)

Monford, Leo G., Jr. (Inventor)

1991-01-01

The apparatus and method are disclosed for releasably connecting first and second objects, where a magnetic end effector may include at least one elongated pin number, a proximal end of which is connected to the first object and the distal end of which may be inserted into a receiving portion in the second object. Latch members are carried by the pin member for radial movement between retracted and expanded positions for releasing and locking, respectively, first and second objects. A plunger member carried by the pin member is axially moveable between first and second positions. In the first plunger position, the latch members are located in the expanded (locked) position and in the second plunger position the latch members are released for movement to retracted or unlocked position. The magnetic end effector is provided for releasable attachment to the first object and for moving the plunger member to the second position, releasing the first object.

Excretion of amine nitrogen and ammonia in urine of pregnant women with type 1 diabetes mellitus

Directory of Open Access Journals (Sweden)

Zulfiya Raisovna Alimetova

2010-12-01

Full Text Available Aim. To study excretion of amine nitrogen and ammonia in urine of pregnant women with type 1 diabetes mellitus depending on gestational ageand albuminuria level. Materials and methods. A total of 60 pregnant women with type 1 diabetes mellitus were examined. Proximal and distal tubular function was estimatedfrom daily excretion of amine nitrogen and ammonia respectively. Results. Daily excretion of amine nitrogen and ammonia in urine of pregnant women with type 1 diabetes mellitus was lower than in healthycontrols in the 2nd trimester regardless of albuminuria and in the 3rd trimester in patients with microalbuminuria (MAU and proteinuria (PU.Ammonia excretion was twice lower than normal in the 2nd trimester in women with MAU and PU, and in the 3rd trimester in patients with PU.Healthy pregnant women showed significant correlation between ammonia and amine nitrogen excretion throughout pregnancy (r?0.833,p

Effect of competing ions and causticization on the ammonia adsorption by a novel poly ligand exchanger (PLE) ammonia adsorption reagent.

Science.gov (United States)

Chen, Quanzhou; Zhou, Kanggen; Hu, Yuanjuan; Liu, Fang; Wang, Aihe

2017-03-01

In this paper, a poly ligand exchanger, Cu(II)-loaded chelating resin named ammonia adsorption reagent (AMAR), bearing the functional group of weak iminodiacetate acid, was prepared to efficiently remove ammonia from solutions. Batch adsorption equilibrium experiments were conducted under a range of conditions. The effects of pH on the removal of ammonia by AMAR were investigated at 25 °C. The copper loaded on the resin forms a complex with NH 3 in solution under alkaline condition. The effect of alkaline dosage (AD) on the ammonia adsorption was investigated. The maximum breakthrough bed volumes were obtained when the AD was set as 0.75 mmol OH - /mL. The higher AD did not guarantee the better ammonia removal efficiency due to the forming of Cu(OH) 2 precipitate between OH - in solutions and Cu(II) on the resin. The effect of competing ions on the adsorption breakthrough curve of virgin AMAR and causticized AMAR was also investigated. The results demonstrated that the existence of competing ions had a negative impact on the adsorption capacity for both virgin AMAR and causticized AMAR. After causticization, the AMAR was more resistant to the competing ions comparing with virgin AMAR. The bivalent Ca 2+ affects the ammonia adsorption more than does the monovalent Na + .

Lipopolysaccharide impairs hepatocyte ureagenesis from ammonia: involvement of mitochondrial aquaporin-8.

Science.gov (United States)

Soria, Leandro R; Marrone, Julieta; Molinas, Sara M; Lehmann, Guillermo L; Calamita, Giuseppe; Marinelli, Raúl A

2014-05-02

We recently reported that hepatocyte mitochondrial aquaporin-8 (mtAQP8) channels facilitate the uptake of ammonia and its metabolism into urea. Here we studied the effect of bacterial lipopolysaccharides (LPS) on ammonia-derived ureagenesis. In LPS-treated rats, hepatic mtAQP8 protein expression and diffusional ammonia permeability (measured utilizing ammonia analogues) of liver inner mitochondrial membranes were downregulated. NMR studies using 15N-labeled ammonia indicated that basal and glucagon-induced ureagenesis from ammonia were significantly reduced in hepatocytes from LPS-treated rats. Our data suggest that hepatocyte mtAQP8-mediated ammonia removal via ureagenesis is impaired by LPS, a mechanism potentially relevant to the molecular pathogenesis of defective hepatic ammonia detoxification in sepsis. Copyright © 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

Simultaneous removal of ammonia and N-nitrosamine precursors from high ammonia water by zeolite and powdered activated carbon.

Science.gov (United States)

Xue, Runmiao; Donovan, Ariel; Zhang, Haiting; Ma, Yinfa; Adams, Craig; Yang, John; Hua, Bin; Inniss, Enos; Eichholz, Todd; Shi, Honglan

2018-02-01

When adding sufficient chlorine to achieve breakpoint chlorination to source water containing high concentration of ammonia during drinking water treatment, high concentrations of disinfection by-products (DBPs) may form. If N-nitrosamine precursors are present, highly toxic N-nitrosamines, primarily N-nitrosodimethylamine (NDMA), may also form. Removing their precursors before disinfection should be a more effective way to minimize these DBPs formation. In this study, zeolites and activated carbon were examined for ammonia and N-nitrosamine precursor removal when incorporated into drinking water treatment processes. The test results indicate that Mordenite zeolite can remove ammonia and five of seven N-nitrosamine precursors efficiently by single step adsorption test. The practical applicability was evaluated by simulation of typical drinking water treatment processes using six-gang stirring system. The Mordenite zeolite was applied at the steps of lime softening, alum coagulation, and alum coagulation with powdered activated carbon (PAC) sorption. While the lime softening process resulted in poor zeolite performance, alum coagulation did not impact ammonia and N-nitrosamine precursor removal. During alum coagulation, more than 67% ammonia and 70%-100% N-nitrosamine precursors were removed by Mordenite zeolite (except 3-(dimethylaminomethyl)indole (DMAI) and 4-dimethylaminoantipyrine (DMAP)). PAC effectively removed DMAI and DMAP when added during alum coagulation. A combination of the zeolite and PAC selected efficiently removed ammonia and all tested seven N-nitrosamine precursors (dimethylamine (DMA), ethylmethylamine (EMA), diethylamine (DEA), dipropylamine (DPA), trimethylamine (TMA), DMAP, and DMAI) during the alum coagulation process. Copyright © 2017. Published by Elsevier B.V.

Inhibition of Direct Electrolytic Ammonia Oxidation Due to a Change in Local pH

International Nuclear Information System (INIS)

Zöllig, Hanspeter; Morgenroth, Eberhard; Udert, Kai M.

2015-01-01

Electrochemical ammonia oxidation has gained a lot of attention recently as an efficient method for ammonia removal from wastewater, for the use in ammonia-based fuel cells and the production of high purity hydrogen. Thermally decomposed iridium oxide films (TDIROF) have been shown to be catalytically active for direct ammonia oxidation in aqueous solutions if NH 3 is present. However, the process was reported to be rapidly inhibited on TDIROF. Herein, we show that this fast inhibition of direct ammonia oxidation does not result from surface poisoning by adsorbed elemental nitrogen (N ads ). Instead, we propose that direct ammonia oxidation and oxygen evolution can lead to a drop of the local pH at the electrode resulting in a low availability of the actual reactant, NH 3 . The hypothesis was tested with cyclic voltammetry (CV) experiments on stagnant and rotating disk electrodes (RDE). The CV experiments on the stagnant electrode revealed that the decrease of the ammonia oxidation peaks was considerably reduced by introducing an idle phase at open circuit potential between subsequent scans. Furthermore, the polarization of the TDIROF electrode into the hydrogen evolution region (HER) resulted in increased ammonia oxidation peaks in the following anodic scans which can be explained with an increased local pH after the consumption of protons in the HER. On the RDE, the ammonia oxidation peaks did not decrease in immediately consecutive scans. These findings would not be expected if surface poisoning was responsible for the fast inhibition but they are in good agreement with the proposed mechanism of pH induced limitation by the reactant, NH 3 . The plausibility of the mechanism was also supported by our numerical simulations of the processes in the Nernstian diffusion layer. The knowledge about this inhibition mechanism of direct ammonia oxidation is especially important for the design of electrochemical cells for wastewater treatment. The mechanism is not only

Effect of gas release in hot molding on flexural strength of composite friction brake

Science.gov (United States)

Rusdja, Andy Permana; Surojo, Eko; Muhayat, Nurul; Raharjo, Wijang Wisnu

2018-02-01

Composite friction brake is a vital part of braking system which serves to reduce the speed of vehicle. To fulfill the requirement of brake performance, composite friction brake must have friction and mechanical characteristic as required. The characteristics of composite friction brake are affected by brake material formulation and manufacturing parameter. In the beginning of hot molding, intermittent hot pressing was carried out to release the gases that consist of ammonia gas and water vapor. In composite friction brake, phenolic resin containing hexamethylenetetramine (HMTA) is often used as a binder. During hot molding, the reaction of phenolic resin and HMTA forms ammonia gas. Hot molding also generates water vapor because raw materials absorb moisture from environment when they are placed in storage. The gas release in hot molding is supposed affecting mechanical properties because it avoid entrapped gas in composite, so that this research investigated effect of gas release on flexural strength. Manufacturing of composite specimen was carried out as follow: mixing of raw materials, cold molding, and hot molding. In this research, duration of intermittent hot pressing and number of gas release were varied. The flexural strength of specimen was measured using three point bending test. The results showed that flexural strength specimens that were manufactured without gas release, using 4 times gas release with intermittent hot pressing for 5 and 10 seconds were not remarkably different. Conversely, hot molding using 4 times gas release with intermittent hot pressing for 15 seconds decreased flexural strength of composite. Hot molding using 2, 4, and 8 times gas release with intermittent hot pressing for 10 seconds also had no effect on increasing flexural strength. Increasing of flexural strength of composite was obtained only by using 6 times gas release with intermittent hot pressing for 10 seconds.

Development and evaluation of accelerated drug release testing methods for a matrix-type intravaginal ring.

Science.gov (United States)

Externbrink, Anna; Eggenreich, Karin; Eder, Simone; Mohr, Stefan; Nickisch, Klaus; Klein, Sandra

2017-01-01

Accelerated drug release testing is a valuable quality control tool for long-acting non-oral extended release formulations. Currently, several intravaginal ring candidates designed for the long-term delivery of steroids or anti-infective drugs are being in the developing pipeline. The present article addresses the demand for accelerated drug release methods for these formulations. We describe the development and evaluation of accelerated release methods for a steroid releasing matrix-type intravaginal ring. The drug release properties of the formulation were evaluated under real-time and accelerated test conditions. Under real-time test conditions drug release from the intravaginal ring was strongly affected by the steroid solubility in the release medium. Under sufficient sink conditions that were provided in release media containing surfactants drug release was Fickian diffusion driven. Both temperature and hydro-organic dissolution media were successfully employed to accelerate drug release from the formulation. Drug release could be further increased by combining the temperature effect with the application of a hydro-organic release medium. The formulation continued to exhibit a diffusion controlled release kinetic under the investigated accelerated conditions. Moreover, the accelerated methods were able to differentiate between different prototypes of the intravaginal ring that exhibited different release profiles under real-time test conditions. Overall, the results of the present study indicate that both temperature and hydro-organic release media are valid parameters for accelerating drug release from the intravaginal ring. Variation of either a single or both parameters yielded release profiles that correlated well with real-time release. Copyright © 2016 Elsevier B.V. All rights reserved.

Ammonia pollution characteristics of centralized drinking water sources in China.

Science.gov (United States)

Fu, Qing; Zheng, Binghui; Zhao, Xingru; Wang, Lijing; Liu, Changming

2012-01-01

The characteristics of ammonia in drinking water sources in China were evaluated during 2005-2009. The spatial distribution and seasonal changes of ammonia in different types of drinking water sources of 22 provinces, 5 autonomous regions and 4 municipalities were investigated. The levels of ammonia in drinking water sources follow the order of river > lake/reservoir > groundwater. The levels of ammonia concentration in river sources gradually decreased from 2005 to 2008, while no obvious change was observed in the lakes/reservoirs and groundwater drinking water sources. The proportion of the type of drinking water sources is different in different regions. In river drinking water sources, the ammonia level was varied in different regions and changed seasonally. The highest value and wide range of annual ammonia was found in South East region, while the lowest value was found in Southwest region. In lake/reservoir drinking water sources, the ammonia levels were not varied obviously in different regions. In underground drinking water sources, the ammonia levels were varied obviously in different regions due to the geological permeability and the natural features of regions. In the drinking water sources with higher ammonia levels, there are enterprises and wastewater drainages in the protected areas of the drinking water sources.

Electrochemical Synthesis of Ammonia in Solid Electrolyte Cells

Directory of Open Access Journals (Sweden)

Ioannis eGaragounis

2014-01-01

Full Text Available Developed in the early 1900's, the Haber-Bosch synthesis is the dominant NH3 synthesis process. Parallel to catalyst optimization, current research efforts are also focused on the investigation of new methods for ammonia synthesis, including the electrochemical synthesis with the use of solid electrolyte cells. Since the first report on Solid State Ammonia Synthesis (SSAS, more than 30 solid electrolyte materials were tested and at least 15 catalysts were used as working electrodes. Thus far, the highest rate of ammonia formation reported is 1.13×10−8 mol s−1 cm−2, obtained at 80°C with a Nafion solid electrolyte and a mixed oxide, SmFe0.7Cu0.1Ni0.2O3, cathode. At high temperatures (>500oC the maximum rate was 9.5*10-9 mol s−1 cm−2 using Ce0.8Y0.2O2-δ -[Ca3(PO42 -K3PO4] as electrolyte and Ag-Pd as cathode. In this paper, the advantages and the disadvantages of SSAS vs the conventional process and the requirements that must be met in order to promote the electrochemical process into an industrial level, are discussed.

Electrochemical Synthesis of Ammonia in Solid Electrolyte Cells

International Nuclear Information System (INIS)

Garagounis, Ioannis; Kyriakou, Vasileios; Skodra, Aglaia; Vasileiou, Eirini; Stoukides, Michael

2014-01-01

Developed in the early 1900s, the “Haber–Bosch” synthesis is the dominant NH 3 synthesis process. Parallel to catalyst optimization, current research efforts are also focused on the investigation of new methods for ammonia synthesis, including the electrochemical synthesis with the use of solid electrolyte cells. Since the first report on Solid State Ammonia Synthesis (SSAS), more than 30 solid electrolyte materials were tested and at least 15 catalysts were used as working electrodes. Thus far, the highest rate of ammonia formation reported is 1.13 × 10 -8 mol s -1 cm -2 , obtained at 80°C with a Nafion solid electrolyte and a mixed oxide, SmFe 0.7 Cu 0.1 Ni 0.2 O 3 , cathode. At high temperatures (>500°C), the maximum rate was 9.5 × 10 −9 mol s -1 cm -2 using Ce 0.8 Y 0.2 O 2-δ –[Ca 3 (PO 4 ) 2 –K 3 PO 4 ] as electrolyte and Ag–Pd as cathode. In this paper, the advantages and the disadvantages of SSAS vs. the conventional process and the requirements that must be met in order to promote the electrochemical process into an industrial level are discussed.

Ammonia and nitrite oxidation in the Eastern Tropical North Pacific

Science.gov (United States)

Peng, Xuefeng; Fuchsman, Clara A.; Jayakumar, Amal; Oleynik, Sergey; Martens-Habbena, Willm; Devol, Allan H.; Ward, Bess B.

2015-12-01

Nitrification plays a key role in the marine nitrogen (N) cycle, including in oceanic oxygen minimum zones (OMZs), which are hot spots for denitrification and anaerobic ammonia oxidation (anammox). Recent evidence suggests that nitrification links the source (remineralized organic matter) and sink (denitrification and anammox) of fixed N directly in the steep oxycline in the OMZs. We performed shipboard incubations with 15N tracers to characterize the depth distribution of nitrification in the Eastern Tropical North Pacific (ETNP). Additional experiments were conducted to investigate photoinhibition. Allylthiourea (ATU) was used to distinguish the contribution of archaeal and bacterial ammonia oxidation. The abundance of archaeal and β-proteobacterial ammonia monooxygenase gene subunit A (amoA) was determined by quantitative polymerase chain reaction. The rates of ammonia and nitrite oxidation showed distinct subsurface maxima, with the latter slightly deeper than the former. The ammonia oxidation maximum coincided with the primary nitrite concentration maximum, archaeal amoA gene maximum, and the subsurface nitrous oxide maximum. Negligible rates of ammonia oxidation were found at anoxic depths, where high rates of nitrite oxidation were measured. Archaeal amoA gene abundance was generally 1 to 2 orders of magnitude higher than bacterial amoA gene abundance, and inhibition of ammonia-oxidizing bacteria with 10 μM ATU did not affect ammonia oxidation rates, indicating the dominance of archaea in ammonia oxidation. These results depict highly dynamic activities of ammonia and nitrite oxidation in the oxycline of the ETNP OMZ.

The effect of climate and climate change on ammonia emissions in Europe

DEFF Research Database (Denmark)

Skjøth, Carsten Ambelas; Geels, Camilla

2013-01-01

Abstract. We present here a dynamical method for modelling temporal and geographical variations in ammonia emissions in regional-scale chemistry transport models (CTMs) and chemistry climate models (CCMs). The method is based on the meteorology in the models and gridded inventories. We use...... to a standard Danish pig stable with 1000 animals and display how emissions from this source would vary geographically throughout central and northern Europe and from year to year. In view of future climate changes, we also evaluate the potential future changes in emission by including temperature projections....... Finally, the climate penalty on ammonia emissions should be taken into account at the policy level such as the NEC and IPPC directives....

Radiological decontamination, survey, and statistical release method for vehicles

International Nuclear Information System (INIS)

Goodwill, M.E.; Lively, J.W.; Morris, R.L.

1996-06-01

Earth-moving vehicles (e.g., dump trucks, belly dumps) commonly haul radiologically contaminated materials from a site being remediated to a disposal site. Traditionally, each vehicle must be surveyed before being released. The logistical difficulties of implementing the traditional approach on a large scale demand that an alternative be devised. A statistical method for assessing product quality from a continuous process was adapted to the vehicle decontamination process. This method produced a sampling scheme that automatically compensates and accommodates fluctuating batch sizes and changing conditions without the need to modify or rectify the sampling scheme in the field. Vehicles are randomly selected (sampled) upon completion of the decontamination process to be surveyed for residual radioactive surface contamination. The frequency of sampling is based on the expected number of vehicles passing through the decontamination process in a given period and the confidence level desired. This process has been successfully used for 1 year at the former uranium millsite in Monticello, Utah (a cleanup site regulated under the Comprehensive Environmental Response, Compensation, and Liability Act). The method forces improvement in the quality of the decontamination process and results in a lower likelihood that vehicles exceeding the surface contamination standards are offered for survey. Implementation of this statistical sampling method on Monticello projects has resulted in more efficient processing of vehicles through decontamination and radiological release, saved hundreds of hours of processing time, provided a high level of confidence that release limits are met, and improved the radiological cleanliness of vehicles leaving the controlled site

Nitrite as a stimulus for ammonia-starved Nitrosomonas europaea

NARCIS (Netherlands)

Laanbroek, H.J.; Bär-Gilissen, M.J.; Hoogveld, H.L.

2002-01-01

Ammonia-starved cells of Nitrosomonas europaea are able to preserve a high level of ammonia-oxidizing activity in the absence of ammonium. However, when the nitrite-oxidizing cells that form part of the natural nitrifying community do not keep pace with the ammonia-oxidizing cells, nitrite

Ammonia-based feedforward and feedback aeration control in activated sludge processes.

Science.gov (United States)

Rieger, Leiv; Jones, Richard M; Dold, Peter L; Bott, Charles B

2014-01-01

Aeration control at wastewater treatment plants based on ammonia as the controlled variable is applied for one of two reasons: (1) to reduce aeration costs, or (2) to reduce peaks in effluent ammonia. Aeration limitation has proven to result in significant energy savings, may reduce external carbon addition, and can improve denitrification and biological phosphorus (bio-P) performance. Ammonia control for limiting aeration has been based mainly on feedback control to constrain complete nitrification by maintaining approximately one to two milligrams of nitrogen per liter of ammonia in the effluent. Increased attention has been given to feedforward ammonia control, where aeration control is based on monitoring influent ammonia load. Typically, the intent is to anticipate the impact of sudden load changes, and thereby reduce effluent ammonia peaks. This paper evaluates the fundamentals of ammonia control with a primary focus on feedforward control concepts. A case study discussion is presented that reviews different ammonia-based control approaches. In most instances, feedback control meets the objectives for both aeration limitation and containment of effluent ammonia peaks. Feedforward control, applied specifically for switching aeration on or off in swing zones, can be beneficial when the plant encounters particularly unusual influent disturbances.

ORTHO-TO-PARA ABUNDANCE RATIO (OPR) OF AMMONIA IN 15 COMETS: OPRs OF AMMONIA VERSUS 14N/15N RATIOS IN CN

International Nuclear Information System (INIS)

Shinnaka, Yoshiharu; Kawakita, Hideyo; Kobayashi, Hitomi; Jehin, Emmanuel; Manfroid, Jean; Hutsemekers, Damien; Arpigny, Claude

2011-01-01

The ortho-to-para abundance ratio (OPR) of cometary molecules is considered to be one of the primordial characteristics of cometary ices. We present OPRs of ammonia (NH 3 ) in 15 comets based on optical high-dispersion spectroscopic observations of NH 2 , which is a photodissociation product of ammonia in the gaseous coma. The observations were mainly carried out with the VLT/UVES. The OPR of ammonia is estimated from the OPR of NH 2 based on the observations of the NH 2 (0, 9, 0) vibronic band. The absorption lines by the telluric atmosphere are corrected and the cometary C 2 emission lines blended with NH 2 lines are removed in our analysis. The ammonia OPRs show a cluster between 1.1 and 1.2 (this corresponds to a nuclear spin temperature of ∼30 K) for all comets in our sample except for 73P/Schwassmann-Wachmann 3 (73P/SW3). Comet 73P/SW3 (both B- and C-fragments) shows the OPR of ammonia consistent with nuclear spin statistical weight ratio (1.0) that indicates a high-temperature limit as nuclear spin temperature. We compared the ammonia OPRs with other properties ( 14 N/ 15 N ratios in CN, D/H ratios of water, and mixing ratios of volatiles). Comet 73P/SW3 is clearly different from the other comets in the plot of ammonia OPRs versus 14 N/ 15 N ratios in CN. The ammonia OPRs of 1.0 and lower 15 N-fractionation of CN in comet 73P/SW3 imply that icy materials in this comet formed under warmer conditions than other comets. Comets may be classified into two groups in the plot of ammonia OPRs against 14 N/ 15 N ratios in CN.

Excretory nitrogen metabolism and defence against ammonia toxicity in air-breathing fishes.

Science.gov (United States)

Chew, S F; Ip, Y K

2014-03-01

With the development of air-breathing capabilities, some fishes can emerge from water, make excursions onto land or even burrow into mud during droughts. Air-breathing fishes have modified gill morphology and morphometry and accessory breathing organs, which would tend to reduce branchial ammonia excretion. As ammonia is toxic, air-breathing fishes, especially amphibious ones, are equipped with various strategies to ameliorate ammonia toxicity during emersion or ammonia exposure. These strategies can be categorized into (1) enhancement of ammonia excretion and reduction of ammonia entry, (2) conversion of ammonia to a less toxic product for accumulation and subsequent excretion, (3) reduction of ammonia production and avoidance of ammonia accumulation and (4) tolerance of ammonia at cellular and tissue levels. Active ammonia excretion, operating in conjunction with lowering of ambient pH and reduction in branchial and cutaneous NH₃ permeability, is theoretically the most effective strategy to maintain low internal ammonia concentrations. NH₃ volatilization involves the alkalization of certain epithelial surfaces and requires mechanisms to prevent NH₃ back flux. Urea synthesis is an energy-intensive process and hence uncommon among air-breathing teleosts. Aestivating African lungfishes detoxify ammonia to urea and the accumulated urea is excreted following arousal. Reduction in ammonia production is achieved in some air-breathing fishes through suppression of amino acid catabolism and proteolysis, or through partial amino acid catabolism leading to alanine formation. Others can slow down ammonia accumulation through increased glutamine synthesis in the liver and muscle. Yet, some others develop high tolerance of ammonia at cellular and tissue levels, including tissues in the brain. In summary, the responses of air-breathing fishes to ameliorate ammonia toxicity are many and varied, determined by the behaviour of the species and the nature of the environment in

Tuneable diode laser spectroscopy correction factor investigation on ammonia measurement

Science.gov (United States)

Li, Nilton; El-Hamalawi, Ashraf; Baxter, Jim; Barrett, Richard; Wheatley, Andrew

2018-01-01

Current diesel engine aftertreatment systems, such as Selective Catalyst Reduction (SCR) use ammonia (NH3) to reduce Nitrogen Oxides (NOx) into Nitrogen (N2) and water (H2O). However, if the reaction between NH3 and NOx is unbalanced, it can lead either NH3 or NOx being released into the environment. As NH3 is classified as a dangerous compound in the environment, its accurate measurement is essential. Tuneable Diode Laser (TDL) spectroscopy is one of the methods used to measure raw emissions inside engine exhaust pipes, especially NH3. This instrument requires a real-time exhaust temperature, pressure and other interference compounds in order to adjust itself to reduce the error in NH3 readings. Most researchers believed that exhaust temperature and pressure were the most influential factors in TDL when measuring NH3 inside exhaust pipes. The aim of this paper was to quantify these interference effects on TDL when undertaking NH3 measurement. Surprisingly, the results show that pressure was the least influential factor when compared to temperature, H2O, CO2 and O2 when undertaking NH3 measurement using TDL.

Synthesis of p-Phenylenediamine (PPD) using Supercritical Ammonia

International Nuclear Information System (INIS)

Cho, Hang-Kyu; Lim, Jong Sung

2015-01-01

In this study, investigated the synthesis method of p-Phenylenediamine (PPD) by amination of p-Diiodobenzene (PDIB) under supercritical ammonia and CuI catalyst conditions. We examined the effects of various process variables (e.g., reaction temperature, pressure, amount of ammonia inserted, amount of catalyst inserted, and reaction time) on the production yield of PPD by analyzing the Gas Chromatography (GC). The experimental results demonstrated that PPD was not produced under non-catalyst conditions, and PPD production yield increased with increasing temperature, pressure, amount of catalyst inserted, and reaction time. However, for the reaction temperature case, it was found that 200 .deg. C was the optimal temperature, because thermal degradation of PPD occurred above 250 .deg. C. In addition, we confirmed the structure of PPD and the bonding characteristics of the amine group via FT-IR and H-NMR analysis

Synthesis of p-Phenylenediamine (PPD) using Supercritical Ammonia

Energy Technology Data Exchange (ETDEWEB)

Cho, Hang-Kyu; Lim, Jong Sung [Sogang University, Seoul (Korea, Republic of)

2015-02-15

In this study, investigated the synthesis method of p-Phenylenediamine (PPD) by amination of p-Diiodobenzene (PDIB) under supercritical ammonia and CuI catalyst conditions. We examined the effects of various process variables (e.g., reaction temperature, pressure, amount of ammonia inserted, amount of catalyst inserted, and reaction time) on the production yield of PPD by analyzing the Gas Chromatography (GC). The experimental results demonstrated that PPD was not produced under non-catalyst conditions, and PPD production yield increased with increasing temperature, pressure, amount of catalyst inserted, and reaction time. However, for the reaction temperature case, it was found that 200 .deg. C was the optimal temperature, because thermal degradation of PPD occurred above 250 .deg. C. In addition, we confirmed the structure of PPD and the bonding characteristics of the amine group via FT-IR and H-NMR analysis.

Silica Gel Coated Spherical Micro resonator for Ultra-High Sensitivity Detection of Ammonia Gas Concentration in Air.

Science.gov (United States)

Mallik, Arun Kumar; Farrell, Gerald; Liu, Dejun; Kavungal, Vishnu; Wu, Qiang; Semenova, Yuliya

2018-01-26

A silica gel coated microsphere resonator is proposed and experimentally demonstrated for measurements of ammonia (NH 3 ) concentration in air with ultra-high sensitivity. The optical properties of the porous silica gel layer change when it is exposed to low (parts per million (ppm)) and even ultra-low (parts per billion (ppb)) concentrations of ammonia vapor, leading to a spectral shift of the WGM resonances in the transmission spectrum of the fiber taper. The experimentally demonstrated sensitivity of the proposed sensor to ammonia is estimated as 34.46 pm/ppm in the low ammonia concentrations range from 4 ppm to 30 ppm using an optical spectrum analyser (OSA), and as 800 pm/ppm in the ultra-low range of ammonia concentrations from 2.5 ppb to 12 ppb using the frequency detuning method, resulting in the lowest detection limit (by two orders of magnitude) reported to date equal to 0.16 ppb of ammonia in air. In addition, the sensor exhibits excellent selectivity to ammonia and very fast response and recovery times measured at 1.5 and 3.6 seconds, respectively. Other attractive features of the proposed sensor are its compact nature, simplicity of fabrication.

[Characteristic of ammonia nitrogen adsorption on karst underground river sediments].

Science.gov (United States)

Guo, Fang; Chen, Kun-Kun; Jiang, Guang-Hui

2011-02-01

Karst aquifers are one of the most important aquifers in Southwestern China. One of the characteristics of karst aquifers is the enhanced permeability permits high flow velocities are capable of transporting suspended and bedload sediments. Mobile sediment in karst may act as a vector for the transport of contaminates. 14 sediment samples were collected from two underground rivers in two typical karst areas in Liuzhou city, Guangxi Autonomous Region, China. According to simulated experiment methods, characteristic of adsorption of ammonia nitrogen on sediment was studied. The results of ammonia nitrogen adsorption dynamics on sediments showed that the maximum adsorption velocity was less than 2 h. The adsorption balance quantity in 5 h accounted for 71% - 98% of the maximum adsorption quantity. The maximum adsorption quantity of ammonia nitrogen was 385.5 mg/kg, which was sediment from a cave in the middle areas of Guancun underground river system. The study of isotherm adsorption indicated adsorption quantity of NH4+ increase followed by incremental balance concentration of NH4+ in the aquatic phase. Adsorption quantity of ammonia nitrogen in sediments has a relative linear relationship with adsorption balance concentrations. Adsorption-desorption balance concentrations were all low, indicating sediments from underground rivers have great adsorption potential. Under the condition of low and high concentrations of ammonia nitrogen in overlying water, Langmuir and Tempkin couldn't simulate or simulate results couldn't reach remarkable level, whilst Linear and Freundlich models could simulate well. Research on different type sediments, sampling times and depths from two underground rivers shows characteristic of ammonia nitrogen adsorption on karst underground river sediments doesn't have good correspondence with the type of sediments. One of the reasons is there is no big difference between sediments in the development of climate, geology, hydrological conditions

Ammonia in the environment: From ancient times to the present

International Nuclear Information System (INIS)

Sutton, Mark A.; Erisman, Jan Willem; Dentener, Frank; Moeller, Detlev

2008-01-01

Recent research on atmospheric ammonia has made good progress in quantifying sources/sinks and environmental impacts. This paper reviews the achievements and places them in their historical context. It considers the role of ammonia in the development of agricultural science and air chemistry, showing how these arose out of foundations in 18th century chemistry and medieval alchemy, and then identifies the original environmental sources from which the ancients obtained ammonia. Ammonia is revealed as a compound of key human interest through the centuries, with a central role played by sal ammoniac in alchemy and the emergence of modern science. The review highlights how recent environmental research has emphasized volatilization sources of ammonia. Conversely, the historical records emphasize the role of high-temperature sources, including dung burning, coal burning, naturally burning coal seams and volcanoes. Present estimates of ammonia emissions from these sources are based on few measurements, which should be a future priority. - Past ammonia applications reveal new emphases in biospheric transformations

Ammonia Induces Autophagy through Dopamine Receptor D3 and MTOR

Science.gov (United States)

Li, Zhiyuan; Ji, Xinmiao; Wang, Wenchao; Liu, Juanjuan; Liang, Xiaofei; Wu, Hong; Liu, Jing; Eggert, Ulrike S.; Liu, Qingsong

2016-01-01

Hyperammonemia is frequently seen in tumor microenvironments as well as in liver diseases where it can lead to severe brain damage or death. Ammonia induces autophagy, a mechanism that tumor cells may use to protect themselves from external stresses. However, how cells sense ammonia has been unclear. Here we show that culture medium alone containing Glutamine can generate milimolar of ammonia at 37 degrees in the absence of cells. In addition, we reveal that ammonia acts through the G protein-coupled receptor DRD3 (Dopamine receptor D3) to induce autophagy. At the same time, ammonia induces DRD3 degradation, which involves PIK3C3/VPS34-dependent pathways. Ammonia inhibits MTOR (mechanistic target of Rapamycin) activity and localization in cells, which is mediated by DRD3. Therefore, ammonia has dual roles in autophagy: one to induce autophagy through DRD3 and MTOR, the other to increase autophagosomal pH to inhibit autophagic flux. Our study not only adds a new sensing and output pathway for DRD3 that bridges ammonia sensing and autophagy induction, but also provides potential mechanisms for the clinical consequences of hyperammonemia in brain damage, neurodegenerative diseases and tumors. PMID:27077655

Closing CO2 Loop in Biogas Production: Recycling Ammonia As Fertilizer.

Science.gov (United States)

He, Qingyao; Yu, Ge; Tu, Te; Yan, Shuiping; Zhang, Yanlin; Zhao, Shuaifei

2017-08-01

We propose and demonstrate a novel system for simultaneous ammonia recovery, carbon capture, biogas upgrading, and fertilizer production in biogas production. Biogas slurry pretreatment (adjusting the solution pH, turbidity, and chemical oxygen demand) plays an important role in the system as it significantly affects the performance of ammonia recovery. Vacuum membrane distillation is used to recover ammonia from biogas slurry at various conditions. The ammonia removal efficiency in vacuum membrane distillation is around 75% regardless of the ammonia concentration of the biogas slurry. The recovered ammonia is used for CO 2 absorption to realize simultaneous biogas upgrading and fertilizer generation. CO 2 absorption performance of the recovered ammonia (absorption capacity and rate) is compared with a conventional model absorbent. Theoretical results on biogas upgrading are also provided. After ammonia recovery, the treated biogas slurry has significantly reduced phytotoxicity, improving the applicability for agricultural irrigation. The novel concept demonstrated in this study shows great potential in closing the CO 2 loop in biogas production by recycling ammonia as an absorbent for CO 2 absorption associated with producing fertilizers.

Roles of renal ammonia metabolism other than in acid-base homeostasis.

Science.gov (United States)

Weiner, I David

2017-06-01

The importance of renal ammonia metabolism in acid-base homeostasis is well known. However, the effects of renal ammonia metabolism other than in acid-base homeostasis are not as widely recognized. First, ammonia differs from almost all other solutes in the urine in that it does not result from arterial delivery. Instead, ammonia is produced by the kidney, and only a portion of the ammonia produced is excreted in the urine, with the remainder returned to the systemic circulation through the renal veins. In normal individuals, systemic ammonia addition is metabolized efficiently by the liver, but in patients with either acute or chronic liver disease, conditions that increase the addition of ammonia of renal origin to the systemic circulation can result in precipitation and/or worsening of hyperammonemia. Second, ammonia appears to serve as an intrarenal paracrine signaling molecule. Hypokalemia increases proximal tubule ammonia production and secretion as well as reabsorption in the thick ascending limb of the loop of Henle, thereby increasing delivery to the renal interstitium and the collecting duct. In the collecting duct, ammonia decreases potassium secretion and stimulates potassium reabsorption, thereby decreasing urinary potassium excretion and enabling feedback correction of the initiating hypokalemia. Finally, the stimulation of renal ammonia metabolism by hypokalemia may contribute to the development of metabolic alkalosis, which in turn can stimulate NaCl reabsorption and contribute to the intravascular volume expansion, increased blood pressure and diuretic resistance that can develop with hypokalemia. The evidence supporting these novel non-acid-base roles of renal ammonia metabolism is discussed in this review.

Experimental determination of methane hydrate formation in the presence of ammonia

Energy Technology Data Exchange (ETDEWEB)

Dong, T.B.; Wang, L.Y.; Liu, A.X.; Guo, X.Q.; Chen, G.J.; Ma, Q.L.; Li, G.W. [China Univ. of Petroleum, Beijng (China). State Key Laboratory of Heavy Oil Processing

2008-07-01

Gas hydrates are non-stoichiometric inclusion compounds that are created by a lattice of water molecules. The host molecule has a strong hydrogen bond and encages low molecular weight gases or volatile liquids. The guest molecules favor hydrate formation. Historically, gas hydrates have been thought to be problematic during natural gas transportation because the formed solid hydrate can block pipelines and cause tubing and casing collapse. However, the discovery of huge deposits of gas hydrates in deep-sea sediments and in permafrost has renewed interest in gas hydrates as a new energy resource. This paper discussed a study that is a part of an ongoing experimental and computational program dealing with the thermodynamics of gas hydrate formation in ammonia-water systems. The purpose of the study was to develop a new method to separate and recycle the vent gas of ammonia synthesis by forming or dissociating hydrate. The hydrate-forming conditions of methane in ammonia and water system were studied and reported in this paper with reference to the experimental apparatus and procedure. The materials and preparation of samples were also explained. The experimental results showed that the ammonia had an inhibitive effect on the hydrate formation. 26 refs., 2 tabs., 3 figs.

Environmental burden by nitrogen from agriculture in the Netherlands. Outline of effects of manure and ammonia measures; Milieubelasting door stikstof uit de Nederlandse landbouw. Verkenning effecten mest- en ammoniakmaatregelen

Energy Technology Data Exchange (ETDEWEB)

Kros, J.; De Vries, W.; Oenema, O. [Divisie Bodem, Alterra, Wageningen Universiteit en Research Centrum, Wageningen (Netherlands)

2004-03-01

The nitrogen emission ceiling has been introduced to be able to assess the effectiveness of measures to control manure and ammonia. This integral method shows the effects of several policy options on the release of nitrogen from the agricultural sector into the environment on a regional scale. [Dutch] Het stikstofplafond is geintroduceerd om de effectiviteit van mest- en ammoniak-maatregelen te beoordelen. Deze integrale methodiek laat op een transparante en samenhangende wijze zien wat de effecten zijn van diverse mogelijke (beleids)maatregelen op de stikstofverliezen uit de landbouw naar het milieu op regionale schaal.

Ammonia emissions in Europe

DEFF Research Database (Denmark)

Jacobsen, Brian H.

2012-01-01

The NEC (National Emission Ceiling) directive has set targets for the 2010 ammonia emissions from a number of European countries. The target will be reached by most EU-countries and the total emission for EU-27 has been reduced by 22% from 1990 to 2007. Denmark is one of the countries with the la......The NEC (National Emission Ceiling) directive has set targets for the 2010 ammonia emissions from a number of European countries. The target will be reached by most EU-countries and the total emission for EU-27 has been reduced by 22% from 1990 to 2007. Denmark is one of the countries...

A Pervaporation Study of Ammonia Solutions Using Molecular Sieve Silica Membranes

Directory of Open Access Journals (Sweden)

Xing Yang

2014-02-01

Full Text Available An innovative concept is proposed to recover ammonia from industrial wastewater using a molecular sieve silica membrane in pervaporation (PV, benchmarked against vacuum membrane distillation (VMD. Cobalt and iron doped molecular sieve silica-based ceramic membranes were evaluated based on the ammonia concentration factor downstream and long-term performance. A modified low-temperature membrane evaluation system was utilized, featuring the ability to capture and measure ammonia in the permeate. It was found that the silica membrane with confirmed molecular sieving features had higher water selectivity over ammonia. This was due to a size selectivity mechanism that favoured water, but blocked ammonia. However, a cobalt doped silica membrane previously treated with high temperature water solutions demonstrated extraordinary preference towards ammonia by achieving up to a 50,000 mg/L ammonia concentration (a reusable concentration level measured in the permeate when fed with 800 mg/L of ammonia solution. This exceeded the concentration factor expected by the benchmark VMD process by four-fold, suspected to be due to the competitive adsorption of ammonia over water into the silica structure with pores now large enough to accommodate ammonia. However, this membrane showed a gradual decline in selectivity, suspected to be due to the degradation of the silica material/pore structure after several hours of operation.

Tools for determining critical levels of atmospheric ammonia under the influence of multiple disturbances

International Nuclear Information System (INIS)

Pinho, P.; Llop, E.; Ribeiro, M.C.; Cruz, C.; Soares, A.; Pereira, M.J.; Branquinho, C.

2014-01-01

Critical levels (CLEs) of atmospheric ammonia based on biodiversity changes have been mostly calculated using small-scale single-source approaches, to avoid interference by other factors, which also influence biodiversity. Thus, it is questionable whether these CLEs are valid at larger spatial scales, in a multi- disturbances context. To test so, we sampled lichen diversity and ammonia at 80 sites across a region with a complex land-cover including industrial and urban areas. At a regional scale, confounding factors such as industrial pollutants prevailed, masking the CLEs. We propose and use a new tool to calculate CLEs by stratifying ammonia concentrations into classes, and focusing on the highest diversity values. Based on the significant correlations between ammonia and biodiversity, we found the CLE of ammonia for Mediterranean evergreen woodlands to be 0.69 μg m −3 , below the previously accepted value of 1.9 μg m −3 , and below the currently accepted pan-European CLE of 1.0 μg m −3 . - Highlights: • Biodiversity responds to multiple disturbances. • This prevents calculation regional critical levels of atmospheric ammonia. • We propose a tool to overcome that, based on the maximum biodiversity observed. • Critical level for Mediterranean evergreen woodlands was revised down to 0.69 μg m −3 . - Critical levels of atmospheric ammonia have not been calculated at a regional scale. Using a new method, we revised down the current Mediterranean evergreen woodlands critical level to 0.69 μg m −3

Bulk-scaffolded hydrogen storage and releasing materials and methods for preparing and using same

Science.gov (United States)

Autrey, S Thomas [West Richland, WA; Karkamkar, Abhijeet J [Richland, WA; Gutowska, Anna [Richland, WA; Li, Liyu [Richland, WA; Li, Xiaohong S [Richland, WA; Shin, Yongsoon [Richland, WA

2011-06-21

Compositions are disclosed for storing and releasing hydrogen and methods for preparing and using same. These hydrogen storage and releasing materials exhibit fast release rates at low release temperatures without unwanted side reactions, thus preserving desired levels of purity and enabling applications in combustion and fuel cell applications.

Arthroscopic release using F and C method versus conventional open release method in the treatment of gluteal muscle contracture: a comparative study.

Science.gov (United States)

Rai, Saroj; Jin, Shengyang; Meng, Chunqing; Chaudhary, Nabin; Tamang, Nira; Wang, Xiaohong; Liu, Xianzhe; Wang, Hong; Yang, Shuhua

2017-03-16

Gluteal muscle contracture (GMC), a debilitating disease, usually starts in early childhood after variable dose of injections around the buttock, if left untreated it worsens gradually and persists throughout the life. Because the disease mostly affects adolescents and adults, there is always an aesthetic concerns. Purposeof the study was to introduce the arthroscopic F and C method of GMC release, and to compare its clinical efficiency with conventional open surgery in terms of clinical outcome, rate of complications, patient's satisfactions, and recurrence. Between Jan 2013 and July 2015, 75 patients received an arthroscopic release with F and C release method and 71 patients received conventional open release of GMC. Primary surgeries in 16 years or older patients were included in the study. Two groups were compared clinically using Hip Outcome Scores - Activities of Daily Living Subscale (HOS-ADL), Hip Outcome Scores - Sports Subscale (HOS-Sports), Visual Analogue Scale (VAS), and Ye et al. evaluation criteria. No statistically significant differences were observed in Hip Outcome Scores - Activities of Daily Living Subscale (HOS-ADL) (P = 0.078), Hip Outcome Scores - Sports Subscale (HOS-Sports) (P = 0.340), and Visual Analogue Scale (VAS) (P = 0.524) between the two groups. 74 (98.7%) patients in the arthroscopic surgery group had good to excellent results, whereas 69 (97.1%) patients in the conventional open surgery group had good to excellent results (P = 0.727). No statistically significant difference was observed in recurrence rate (P = 0.612). Statistically significant differences were observed in incision length, use of post-operative analgesia, post-operative off-bed activity, and hospital stay. Complications were significantly higher in the conventional open surgery group (n = 21) than in the arthroscopic surgery group (n = 10) (P = 0.016). More importantly, cosmetic satisfaction was 100% in arthroscopic release group

Operation experience with elevated ammonia

International Nuclear Information System (INIS)

Vankova, Katerina; Kysela, Jan; Malac, Miroslav; Petrecky, Igor; Svarc, Vladimir

2011-01-01

The 10 VVER units in the Czech and Slovak Republics are all in very good water chemistry and radiation condition, yet questions have arisen regarding the optimization of cycle chemistry and improved operation in these units. To address these issues, a comprehensive experimental program for different water chemistries of the primary circuit was carried out at the Rez Nuclear Research Institute, Czech Republic, with the goal of judging the influence of various water chemistries on radiation build-up. Four types of water chemistries were compared: standard VVER water chemistry (in common use), direct hydrogen dosing without ammonia, standard VVER water chemistry with elevated ammonia levels, and zinc dosing to standard VVER water chemistry. The test results showed that the types of water chemistry other than the common one have benefits for the operation of the nuclear power plant (NPP) primary circuit. Operation experience with elevated ammonia at NPP Dukovany Units 3 and 4 is presented which validates the experimental results, demonstrating improved corrosion product volume activity. (orig.)

Ammonia transformation in a biotrickling air filter

DEFF Research Database (Denmark)

Nielsen, Lars Peter; Nielsen, Marie Louise; Andersen, Mathias

2007-01-01

A simple, tubular biotrickling filter was designed for optimal removal of ammonia and odour in ventilation air from a pig house. The removal and transformation of ammonia was studied in detail by analysis and modelling of chemical gradients through the filter. Good correspondence between measurem...

Effects of ammonia concentration on the thermodynamic performances of ammonia–water based power cycles

International Nuclear Information System (INIS)

Kim, Kyoung Hoon; Han, Chul Ho; Kim, Kyoungjin

2012-01-01

The power generation systems using a binary working fluid such as ammonia–water mixture are proven to be the feasible method for utilizing a low-temperature waste heat source. In this work, ammonia–water based Rankine (AWR) regenerative Rankine (AWRR) power generation cycles are comparatively analyzed by investigating the effects of ammonia mass concentration in the working fluid on the thermodynamic performances of systems. Temperature distributions of fluid streams in the heat exchanging devices are closely examined at different levels of ammonia concentration and they might be the most important design consideration in optimizing the power systems using a binary working fluid. The analysis shows that the lower limit of workable ammonia concentration decreases with increasing turbine inlet pressure. Results also show that both the thermal and exergy efficiencies of AWRR system are generally better than those of AWR system, and can have peaks at the minimum allowable ammonia concentrations in the working range of system operation.

A new sensor for ammonia based on cyanidin-sensitized titanium dioxide film operating at room temperature

Energy Technology Data Exchange (ETDEWEB)

Xiao-wei, Huang [School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, 212013 Zhenjiang, Jiangsu (China); Xiao-bo, Zou, E-mail: zou_xiaobo@ujs.edu.cn [School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, 212013 Zhenjiang, Jiangsu (China); Key Laboratory of Modern Agricultural Equipment and Technology, 301 Xuefu Road, 212013 Zhenjiang, Jiangsu (China); Ji-yong, Shi; Jie-wen, Zhao; Yanxiao, Li [School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, 212013 Zhenjiang, Jiangsu (China); Limin, Hao; Jianchun, Zhang [The Research Center of China Hemp Materials, Beijing (China)

2013-07-17

Graphical abstract: -- Highlights: •TiO{sub 2} was prepared by sol–gel method film and then functionalized with the cyanidin dye. •The morphology and the absorption spectra of films were examined. •The hybrid organic–inorganic formed film here can detect ammonia reversibly at room temperature. •The low humidity could promote the sensitivity of the sensors. -- Abstract: Design and fabrication of an ammonia sensor operating at room temperature based on pigment-sensitized TiO{sub 2} films was described. TiO{sub 2} was prepared by sol–gel method and deposited on glass slides containing gold electrodes. Then, the film immersed in a 2.5 × 10{sup −4} M ethanol solution of cyanidin to absorb the pigment. The hybrid organic–inorganic formed film here can detect ammonia reversibly at room temperature. The relative change resistance of the films at a potential difference of 1.5 V is determined when the films are exposed to atmospheres containing ammonia vapors with concentrations over the range 10–50 ppm. The relative change resistance, S, of the films increased almost linearly with increasing concentrations of ammonia (r = 0.92). The response time to increasing concentrations of the ammonia is about 180–220 s, and the corresponding values for decreasing concentrations 240–270 s. At low humidity, ammonia could be ionized by the cyanidin on the TiO{sub 2} film and thereby decrease in the proton concentration at the surface. Consequently, more positively charged holes at the surface of the TiO{sub 2} have to be extracted to neutralize the adsorbed cyanidin and water film. The resistance response to ammonia of the sensors was nearly independent on temperature from 10 to 50 °C. These results are not actually as good as those reported in the literature, but this preliminary work proposes simpler and cheaper processes to realize NH{sub 3} sensor for room temperature applications.

Immobilization of ammonia-oxidizing bacteria by polyvinyl alcohol and sodium alginate.

Science.gov (United States)

Dong, Yuwei; Zhang, Yanqiu; Tu, Baojun

Ammonia-oxidizing bacteria were immobilized by polyvinyl alcohol (PVA) and sodium alginate. The immobilization conditions and ammonia oxidation ability of the immobilized bacteria were investigated. The following immobilization conditions were observed to be optimal: PVA, 12%; sodium alginate, 1.1%; calcium chloride, 1.0%; inoculum concentration, 1.3 immobilized balls/mL of immobilized medium; pH, 10; and temperature, 30°C. The immobilized ammonia-oxidizing bacteria exhibited strong ammonia oxidation ability even after being recycled four times. The ammonia nitrogen removal rate of the immobilized ammonia-oxidizing bacteria reached 90.30% under the optimal immobilization conditions. When compared with ammonia-oxidizing bacteria immobilized by sodium alginate alone, the bacteria immobilized by PVA and sodium alginate were superior with respect to pH resistance, the number of reuses, material cost, heat resistance, and ammonia oxidation ability. Copyright © 2017 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

SIRT5 regulation of ammonia-induced autophagy and mitophagy

Science.gov (United States)

Polletta, Lucia; Vernucci, Enza; Carnevale, Ilaria; Arcangeli, Tania; Rotili, Dante; Palmerio, Silvia; Steegborn, Clemens; Nowak, Theresa; Schutkowski, Mike; Pellegrini, Laura; Sansone, Luigi; Villanova, Lidia; Runci, Alessandra; Pucci, Bruna; Morgante, Emanuela; Fini, Massimo; Mai, Antonello; Russo, Matteo A; Tafani, Marco

2015-01-01

In liver the mitochondrial sirtuin, SIRT5, controls ammonia detoxification by regulating CPS1, the first enzyme of the urea cycle. However, while SIRT5 is ubiquitously expressed, urea cycle and CPS1 are only present in the liver and, to a minor extent, in the kidney. To address the possibility that SIRT5 is involved in ammonia production also in nonliver cells, clones of human breast cancer cell lines MDA-MB-231 and mouse myoblast C2C12, overexpressing or silenced for SIRT5 were produced. Our results show that ammonia production increased in SIRT5-silenced and decreased in SIRT5-overexpressing cells. We also obtained the same ammonia increase when using a new specific inhibitor of SIRT5 called MC3482. SIRT5 regulates ammonia production by controlling glutamine metabolism. In fact, in the mitochondria, glutamine is transformed in glutamate by the enzyme glutaminase, a reaction producing ammonia. We found that SIRT5 and glutaminase coimmunoprecipitated and that SIRT5 inhibition resulted in an increased succinylation of glutaminase. We next determined that autophagy and mitophagy were increased by ammonia by measuring autophagic proteolysis of long-lived proteins, increase of autophagy markers MAP1LC3B, GABARAP, and GABARAPL2, mitophagy markers BNIP3 and the PINK1-PARK2 system as well as mitochondrial morphology and dynamics. We observed that autophagy and mitophagy increased in SIRT5-silenced cells and in WT cells treated with MC3482 and decreased in SIRT5-overexpressing cells. Moreover, glutaminase inhibition or glutamine withdrawal completely prevented autophagy. In conclusion we propose that the role of SIRT5 in nonliver cells is to regulate ammonia production and ammonia-induced autophagy by regulating glutamine metabolism. PMID:25700560

Radiation Chemistry in Ammonia-Water Ices

Science.gov (United States)

Loeffler, M. J.; Raut, U.; Baragiola, R. A.

2010-01-01

We studied the effects of 100 keV proton irradiation on films of ammonia-water mixtures between 20 and 120 K. Irradiation destroys ammonia, leading to the formation and trapping of H2, N2 NO, and N2O, the formation of cavities containing radiolytic gases, and ejection of molecules by sputtering. Using infrared spectroscopy, we show that at all temperatures the destruction of ammonia is substantial, but at higher temperatures (120 K), it is nearly complete (approximately 97% destroyed) after a fluence of 10(exp 16) ions per square centimeter. Using mass spectroscopy and microbalance gravimetry, we measure the sputtering yield of our sample and the main components of the sputtered flux. We find that the sputtering yield depends on fluence. At low temperatures, the yield is very low initially and increases quadratically with fluence, while at 120 K the yield is constant and higher initially. The increase in the sputtering yield with fluence is explained by the formation and trapping of the ammonia decay products, N2 and H2 which are seen to be ejected from the ice at all temperatures.

Investigation of Pristine Graphite Oxide as Room-Temperature Chemiresistive Ammonia Gas Sensing Material

Directory of Open Access Journals (Sweden)

Alexander G. Bannov

2017-02-01

Full Text Available Graphite oxide has been investigated as a possible room-temperature chemiresistive sensor of ammonia in a gas phase. Graphite oxide was synthesized from high purity graphite using the modified Hummers method. The graphite oxide sample was investigated using scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, thermogravimetry and differential scanning calorimetry. Sensing properties were tested in a wide range of ammonia concentrations in air (10–1000 ppm and under different relative humidity levels (3%–65%. It was concluded that the graphite oxide–based sensor possessed a good response to NH3 in dry synthetic air (ΔR/R0 ranged from 2.5% to 7.4% for concentrations of 100–500 ppm and 3% relative humidity with negligible cross-sensitivity towards H2 and CH4. It was determined that the sensor recovery rate was improved with ammonia concentration growth. Increasing the ambient relative humidity led to an increase of the sensor response. The highest response of 22.2% for 100 ppm of ammonia was achieved at a 65% relative humidity level.

Electrochemical monitoring of ammonia during anaerobic digestion

DEFF Research Database (Denmark)

Zhao, Nannan; Angelidaki, Irini; Zhang, Yifeng

Ammonia is known as key inhibitor to methanogens in anaerobic digestion (AD) process. It’s of importance to develop efficient tool for ammonia monitoring. In this study, an electrolysis cell (EC) coupled with a complete nitrification reactor was developed as sensor for real time and online monito...

Catalytic Organometallic Reactions of Ammonia

Science.gov (United States)

Klinkenberg, Jessica L.

2012-01-01

Until recently, ammonia had rarely succumbed to catalytic transformations with homogeneous catalysts, and the development of such reactions that are selective for the formation of single products under mild conditions has encountered numerous challenges. However, recently developed catalysts have allowed several classes of reactions to create products with nitrogen-containing functional groups from ammonia. These reactions include hydroaminomethylation, reductive amination, alkylation, allylic substitution, hydroamination, and cross-coupling. This Minireview describes examples of these processes and the factors that control catalyst activity and selectivity. PMID:20857466

Removal of ammonia solutions used in catalytic wet oxidation processes.

Science.gov (United States)

Hung, Chang Mao; Lou, Jie Chung; Lin, Chia Hua

2003-08-01

Ammonia (NH(3)) is an important product used in the chemical industry, and is common place in industrial wastewater. Industrial wastewater containing ammonia is generally either toxic or has concentrations or temperatures such that direct biological treatment is unfeasible. This investigation used aqueous solutions containing more of ammonia for catalytic liquid-phase oxidation in a trickle-bed reactor (TBR) based on Cu/La/Ce composite catalysts, prepared by co-precipitation of Cu(NO(3))(2), La(NO(3))(2), and Ce(NO(3))(3) at 7:2:1 molar concentrations. The experimental results indicated that the ammonia conversion of the wet oxidation in the presence of the Cu/La/Ce composite catalysts was determined by the Cu/La/Ce catalyst. Minimal ammonia was removed from the solution by the wet oxidation in the absence of any catalyst, while approximately 91% ammonia removal was achieved by wet oxidation over the Cu/La/Ce catalyst at 230 degrees C with oxygen partial pressure of 2.0 MPa. Furthermore, the effluent streams were conducted at a liquid hourly space velocity of under 9 h(-1) in the wet catalytic processes, and a reaction pathway was found linking the oxidizing ammonia to nitric oxide, nitrogen and water. The solution contained by-products, including nitrates and nitrites. Nitrite selectivity was minimized and ammonia removal maximized when the feed ammonia solution had a pH of around 12.0.

Ammonia removal via microbial fuel cell (MFC) dynamic reactor

Science.gov (United States)

Alabiad, I.; Ali, U. F. M.; Zakarya, I. A.; Ibrahim, N.; Radzi, R. W.; Zulkurnai, N. Z.; Azmi, N. H.

2017-06-01

Landfill leachate is generally known as high-strength wastewater that is difficult to handle and contains dissolved extracts and suspended matter. Microbial fuel cells (MFCs) were designed to treat landfill leachate while continuously producing power (voltage output). Three different anodes were tested in MFC reactors: carbon black, activated carbon, and zinc electrodes. Movements in the MFC reactor during treatment were also a key factor for testing. Results showed a difference in ammonia levels in the three anodes used. The study compared the efficiency of static and dynamic modes of MFC in removing ammonia. Continual leachate movement in the reactor could increase the rate of removal of the ammonia components. The setup provided a viable condition for maximum removal because the reactor movement caused the sludge to disintegrate, which allowed ammonia to separate easily from the parent leachate. Ammonia removal also resulted from the transfer of ammonium through the membrane or from ammonia loss. Constant exchange of ionic content benefited the MFC performance by increasing power production and decreasing internal electrode material resistance. This paper presents the results of the analyses of leachate treatment from the solid waste landfill located in Padang Siding Landfill, Perlis. The performance of ammonia removal was enhanced using different types of electrodes. In both modes, activated carbon performed better than black carbon and zinc. The respective percentages of ammonia removal for activated carbon of dynamic over static were 96.6%, 66.6%, and 92.8% for activated carbon, zinc, and black carbon. The results provide further information on the possibility of using MFCs in landfill leachate treatment systems.

Adsorption of Ammonia on Regenerable Carbon Sorbents

Science.gov (United States)

Wójtowicz, Marek A.; Cosgrove, Jesph E.; Serio, Michael A..; Wilburn, Monique

2015-01-01

Results are presented on the development of reversible sorbents for the combined carbon dioxide, moisture, and trace-contaminant (TC) removal for use in Extravehicular Activities (EVAs), and more specifically in the Primary Life Support System (PLSS). The currently available life support systems use separate units for carbon dioxide, trace contaminants, and moisture control, and the long-term objective is to replace the above three modules with a single one. Data on sorption and desorption of ammonia, which is a major TC of concern, are presented in this paper. The current TC-control technology involves the use of a packed bed of acid-impregnated granular charcoal, which is non-regenerable, and the carbon-based sorbent under development in this project can be regenerated by exposure to vacuum at room temperature. In this study, several carbon sorbents were fabricated and tested for ammonia sorption. Ammonia-sorption capacity was related to carbon pore structure characteristics, and the temperature of oxidative carbon-surface treatment was optimized for enhanced ammonia-sorption performance.

Mass transfer of ammonia escape and CO2 absorption in CO2 capture using ammonia solution in bubbling reactor

International Nuclear Information System (INIS)

Ma, Shuangchen; Chen, Gongda; Zhu, Sijie; Han, Tingting; Yu, Weijing

2016-01-01

Highlights: • Mass transfer coefficient models of ammonia escape were built. • Influences of temperature, inlet CO 2 and ammonia concentration were studied. • Mass transfer coefficients of ammonia escape and CO 2 absorption were obtained. • Studies can provide the basic data as a reference guideline for process application. - Abstract: The mass transfer of CO 2 capture using ammonia solution in the bubbling reactor was studied; according to double film theory, the mass transfer coefficient models and interface area model were built. Through our experiments, the overall volumetric mass transfer coefficients were obtained, while the interface areas in unit volume were estimated. The volumetric mass transfer coefficients of ammonia escaping during the experiment were 1.39 × 10 −5 –4.34 × 10 −5 mol/(m 3 s Pa), and the volumetric mass transfer coefficients of CO 2 absorption were 2.86 × 10 −5 –17.9 × 10 −5 mol/(m 3 s Pa). The estimated interface area of unit volume in the bubbling reactor ranged from 75.19 to 256.41 m 2 /m 3 , making the bubbling reactor a viable choice to obtain higher mass transfer performance than the packed tower or spraying tower.

Ammonia from manure slurry and measures for its reduction - in particular in connection with fermentation

International Nuclear Information System (INIS)

Hersener, J.-L.; Meier, U.; Dinkel, F.

2002-01-01

This report for the Swiss Federal Office of Energy (SFOE) presents the results of a study made to demonstrate the potential of reducing ammonia emissions from manure slurries in connection with anaerobic digestion. The various methods of treatment that were assessed, including digestion, aeration, separation of the liquid phase, additives, acidification, flocculation, precipitation and stripping are discussed. The findings on the effectiveness of the different treatment methods are compared with normal slurry storage and distribution methods (open pits for storage, distribution by splash plate). Recommendations on convenient methods for reducing ammonia losses are made, whereby the authors state their opinion that digestion is not to be recommended and that separation is practical and can be realised rapidly

New efficient catalyst for ammonia synthesis: barium-promoted cobalt on carbon

DEFF Research Database (Denmark)

Hagen, Stefan; Barfod, Rasmus; Fehrmann, Rasmus

2002-01-01

Barium-promoted cobalt catalysts supported on carbon exhibit higher ammonia activities at synthesis temperatures than the commercial, multipromoted iron catalyst and also a lower ammonia......Barium-promoted cobalt catalysts supported on carbon exhibit higher ammonia activities at synthesis temperatures than the commercial, multipromoted iron catalyst and also a lower ammonia...

Cerebral ammonia uptake and accumulation during prolonged exercise in humans

DEFF Research Database (Denmark)

Nybo, Lars; Dalsgaard, Mads K.; Steensberg, Adam

2005-01-01

We evaluated whether peripheral ammonia production during prolonged exercise enhances the uptake and subsequent accumulation of ammonia within the brain. Two studies determined the cerebral uptake of ammonia (arterial and jugular venous blood sampling combined with Kety-Schmidt-determined cerebral...... blood flow; n = 5) and the ammonia concentration in the cerebrospinal fluid (CSF; n = 8) at rest and immediately following prolonged exercise either with or without glucose supplementation. There was a net balance of ammonia across the brain at rest and at 30 min of exercise, whereas 3 h of exercise...... exercise with glucose, and further to 16.1 ± 3.3 µM after the placebo trial (P

A continuous-flow denuder for the measurement of ambient concentrations and surface-exchange fluxes of ammonia

Science.gov (United States)

Wyers, G. P.; Otjes, R. P.; Slanina, J.

A new diffusion denuder is described for the continuous measurement of atmospheric ammonia. Ammonia is collected in an absorption solution in a rotating denuder, separated from interfering compounds by diffusion through a semi-permeable membrane and detected by conductometry. The method is free from interferences by other atmospheric gases, with the exception of volatile amines. The detection limit is 6 ng m -3 for a 30-min integration time. This compact instrument is fully automated and suited for routine deployment in field studies. The precision is sufficiently high for micrometeorological studies of air-surface exchange of ammonia.

Hygroscopicity and ammonia volatilization losses from nitrogen sources in coated urea

Directory of Open Access Journals (Sweden)

Letícia de Abreu Faria

2014-06-01

Full Text Available Hygroscopic fertilizers tend to absorb moisture from the air and may have undesirable characteristics such as moistness, clumping and lower fluidity, hampering the application. The increasing use of urea is due to its numerous advantages, although this nitrogen (N source is highly susceptible to volatilization losses, particularly when applied to the soil surface of management systems with conservation of crop residues. The volatilization losses can be minimized by slow or controlled-release fertilizers, with controlled water solubility of the urea-coating materials; and by stabilized fertilizers, which prolong the period during which N remains in the amide or ammonia forms by urease inhibitors. This study evaluated the hygroscopicity of and ammonia volatilization from urea coated with boric acid and copper sulfate or with sulfur. The hygroscopicity of the sources was evaluated over time after exposure to five levels of relative humidity (RH and volatilization evaluated after application to the soil surface covered with sugarcane trash. Ammonium nitrate has a low potential for volatilization losses, but is highly hygroscopic. Although coating with boric acid and copper sulfate or elemental sulfur reduced the critical humidity level of urea, the delay in the volatilization process is a potential positive factor.

Application of tumbling melt granulation (TMG) method to prepare controlled-release fine granules.

Science.gov (United States)

Maejima, T; Kubo, M; Osawa, T; Nakajima, K; Kobayashi, M

1998-03-01

The tumbling melt granulation (TMG) method was applied to prepare controlled-release fine granules of diltiazem hydrochloride (DH). The entire process, from the preparation of the cores by the adherence of DH to the sucrose crystal to the subsequent coating of the controlled-release layer, was performed without using any solvent. A mixture of meltable material, talc, and ethylcellulose was used for the controlled-release layer and controlled-release fine granules approximately 400 microns in diameter were obtained with excellent producibility. The dissolution rate of DH from these fine granules was similar to that of a once-a-day dosage form obtained in the market; further, the dependency of the dissolution profile on pH of the media was less. Thus, it was concluded that this TMG method was very useful for preparing not only controlled-release beads of granule size (usually 500 to 1400 microns) but also fine granules.

40 CFR 418.20 - Applicability; description of the ammonia subcategory.

Science.gov (United States)

2010-07-01

... ammonia subcategory. 418.20 Section 418.20 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS FERTILIZER MANUFACTURING POINT SOURCE CATEGORY Ammonia Subcategory § 418.20 Applicability; description of the ammonia subcategory. The provisions of this subpart are...

Ammonia levels and the severity of hepatic encephalopathy

International Nuclear Information System (INIS)

Qureshi, M.O.; Khokhar, N.; Shafqat, F.

2014-01-01

Objective: To evaluate the correlation between ammonia levels with the severity of HE in patients coming to the tertiary care hospital with liver cirrhosis and hepatic encephalopathy (HE). Study Design: Descriptive, analytical study. Place and Duration of Study: Shifa International Hospital, Islamabad, from January 2011 to February 2012. Methodology: A total of 135 patients with liver cirrhosis and HE had serum ammonia levels measured on admission. The diagnosis of HE was based on clinical criteria, and its severity was graded according to the West Haven Criteria for grading of mental status. Ammonia levels were correlated with the severity of HE using Spearman rank correlation. Results: Out of 20 patients with normal ammonia levels, 13 (65%) were in HE I-II, 6 (30%) were in grade-III, while 1 (5%) patient was in grade-IV HE. Out of 45 patients with mild hyperammonemia, 27 (60%) were in grade I-II, 12 (26%) were in grade-III and 6 (13%) were in grade-IV HE. Out of 34 patients with moderate hyperammonemia, 9 (26%) were in grade I-II, 18 (53%) were in grade-III, and 7 (20%) were in grade-IV HE. Out of 36 patients with severe hyperammonemia, 31 (86%) patients were in grade-IV HE (p < 0.001). Conclusion: Ammonia levels correlated with the severity of hepatic encephalopathy. Greater the ammonia level, severe is the grade of hepatic encephalopathy. (author)

Thermodynamic Model for the Ammonia-Water System

DEFF Research Database (Denmark)

Thomsen, Kaj; Rasmussen, Peter

2000-01-01

The ammonia-water system is described by the Extended UNIQUAC model, which is an electrolyte model, formed by combining the original UNIQUAC model, the Debye-Hückel law and the Soave-Redlich-Kwong equation of state. The model is limited to temperatures below the critical temperature of ammonia. V...

Chilled ammonia process for CO2 capture

DEFF Research Database (Denmark)

Darde, Victor Camille Alfred; Thomsen, Kaj; van Well, Willy J. M

2009-01-01

The chilled ammonia process absorbs the CO2 at low temperature (2-10 degrees C). The heat of absorption of carbon dioxide by ammonia is significantly lower than for amines. In addition, degradation problems can be avoided and a high carbon dioxide capacity is achieved. Hence, this process shows...

Ammonia Concentrations in Different Aquaculture Holding Tanks ...

African Journals Online (AJOL)

High unionized ammonia recorded in the collapsible and concrete ponds was from excretion of high protein rich feed, decomposition of uneaten feed, high stocking density, low water exchange rates, water source and the alkaline medium of the systems. Low unionized ammonia in earthen pond and natural pond was ...

Discussion on the methods for calculation release limits for low-level radioactive waste

International Nuclear Information System (INIS)

Cao Fengbo; Liu Xiaochao

2012-01-01

The release request for low-level radioactive waste are briefly described in this paper. Associating with the conditions of low-level radioactive waste of some radioactive waste processing station, the methods and gist for calculating release limits for low-level radioactive waste with national release limits and annual effective dose limit for the public or the occupation are discussed. Then release limits for the low-level radioactive waste are also proposed. (authors)

Metabolic recycling of ammonia via glutamate dehydrogenase supports breast cancer biomass.

Science.gov (United States)

Spinelli, Jessica B; Yoon, Haejin; Ringel, Alison E; Jeanfavre, Sarah; Clish, Clary B; Haigis, Marcia C

2017-11-17

Ammonia is a ubiquitous by-product of cellular metabolism; however, the biological consequences of ammonia production are not fully understood, especially in cancer. We found that ammonia is not merely a toxic waste product but is recycled into central amino acid metabolism to maximize nitrogen utilization. In our experiments, human breast cancer cells primarily assimilated ammonia through reductive amination catalyzed by glutamate dehydrogenase (GDH); secondary reactions enabled other amino acids, such as proline and aspartate, to directly acquire this nitrogen. Metabolic recycling of ammonia accelerated proliferation of breast cancer. In mice, ammonia accumulated in the tumor microenvironment and was used directly to generate amino acids through GDH activity. These data show that ammonia is not only a secreted waste product but also a fundamental nitrogen source that can support tumor biomass. Copyright © 2017, American Association for the Advancement of Science.

Adsorption study of Ammonia Nitrogen by watermelon rind

Science.gov (United States)

Ibrahim, A.; Yusof, L.; Beddu, N. S.; Galasin, N.; Lee, P. Y.; Lee, R. N. S.; Zahrim, A. Y.

2016-06-01

The utilization of fruit waste for low-cost adsorbents as a replacement for costly conventional methods of removing ammonia nitrogen from wastewater has been reviewed. The adsorption studies were conducted as a function of contact time and adsorbent dosage and it were carried out on four different adsorbents; fresh watermelon rind and modified watermelon rind with sodium hydroxide (NaOH), potassium hydroxide (KOH) and sulphuric acid (H2SO4). Adsorbents were tested for characterization by using zeta potential test and all samples shows negative values thus makes it favourable for the adsorption process. The batch experimental result showed that adsorption process is rapid and equilibrium was established within 40 minutes of contact time. The ammonia nitrogen removal rate amounted in range of 96% to 99%, and the adsorption capacities were in range of 1.21 to 1.24 mg/g for all four different types of adsorbents used.

Ammonia removal in electrochemical oxidation: Mechanism and pseudo-kinetics

International Nuclear Information System (INIS)

Li Liang; Liu Yan

2009-01-01

This paper investigated the mechanism and pseudo-kinetics for removal of ammonia by electrochemical oxidation with RuO 2 /Ti anode using batch tests. The results show that the ammonia oxidation rates resulted from direct oxidation at electrode-liquid interfaces of the anode by stepwise dehydrogenation, and from indirect oxidation by hydroxyl radicals were so slow that their contribution to ammonia removal was negligible under the condition with Cl - . The oxidation rates of ammonia ranged from 1.0 to 12.3 mg N L -1 h -1 and efficiency reached nearly 100%, primarily due to the indirect oxidation of HOCl, and followed pseudo zero-order kinetics in electrochemical oxidation with Cl - . About 88% ammonia was removed from the solution. The removed one was subsequently found in the form of N 2 in the produced gas. The rate at which Cl - lost electrons at the anode was a major factor in the overall ammonia oxidation. Current density and Cl - concentration affected the constant of the pseudo zero-order kinetics, expressed by k = 0.0024[Cl - ] x j. The ammonia was reduced to less than 0.5 mg N L -1 after 2 h of electrochemical oxidation for the effluent from aerobic or anaerobic reactors which treated municipal wastewater. This result was in line with the strict discharge requirements

Electrochemical Synthesis of Ammonia in Solid Electrolyte Cells

Energy Technology Data Exchange (ETDEWEB)

Garagounis, Ioannis; Kyriakou, Vasileios [Department of Chemical Engineering, Aristotle University of Thessaloniki, Thessaloniki (Greece); Chemical Processes and Energy Resources Institute, Center for Research and Technology Hellas, Thessaloniki (Greece); Skodra, Aglaia [Chemical Processes and Energy Resources Institute, Center for Research and Technology Hellas, Thessaloniki (Greece); Vasileiou, Eirini; Stoukides, Michael, E-mail: stoukidi@cperi.certh.gr [Department of Chemical Engineering, Aristotle University of Thessaloniki, Thessaloniki (Greece); Chemical Processes and Energy Resources Institute, Center for Research and Technology Hellas, Thessaloniki (Greece)

2014-01-17

Developed in the early 1900s, the “Haber–Bosch” synthesis is the dominant NH{sub 3} synthesis process. Parallel to catalyst optimization, current research efforts are also focused on the investigation of new methods for ammonia synthesis, including the electrochemical synthesis with the use of solid electrolyte cells. Since the first report on Solid State Ammonia Synthesis (SSAS), more than 30 solid electrolyte materials were tested and at least 15 catalysts were used as working electrodes. Thus far, the highest rate of ammonia formation reported is 1.13 × 10{sup -8} mol s{sup -1} cm{sup -2}, obtained at 80°C with a Nafion solid electrolyte and a mixed oxide, SmFe{sub 0.7}Cu{sub 0.1}Ni{sub 0.2}O{sub 3}, cathode. At high temperatures (>500°C), the maximum rate was 9.5 × 10{sup −9} mol s{sup -1} cm{sup -2} using Ce{sub 0.8}Y{sub 0.2}O{sub 2-δ}–[Ca{sub 3}(PO{sub 4}){sub 2}–K{sub 3}PO{sub 4}] as electrolyte and Ag–Pd as cathode. In this paper, the advantages and the disadvantages of SSAS vs. the conventional process and the requirements that must be met in order to promote the electrochemical process into an industrial level are discussed.

Ammonia synthesis at low temperatures

DEFF Research Database (Denmark)

Rod, Thomas Holm; Logadottir, Ashildur; Nørskov, Jens Kehlet

2000-01-01

have been carried out to evaluate its feasibility. The calculations suggest that it might be possible to catalytically produce ammonia from molecular nitrogen at low temperatures and pressures, in particular if energy is fed into the process electrochemically. (C) 2000 American Institute of Physics.......Density functional theory (DFT) calculations of reaction paths and energies for the industrial and the biological catalytic ammonia synthesis processes are compared. The industrial catalyst is modeled by a ruthenium surface, while the active part of the enzyme is modeled by a MoFe6S9 complex...

Nitrogen fate model for gas-phase ammonia-enhanced in situ bioventing

International Nuclear Information System (INIS)

Marshall, T.R.

1995-01-01

Subsurface bioremediation of contaminants is sometimes limited by the availability of nitrogen. Introduction of gaseous ammonia to the subsurface is a feasible and economical approach to enhance biodegradation in some environments. A gaseous nutrient source may be a practical option for sites where surface application of liquid nutrients is not possible, such as sites with shallow groundwater or sites with surface operations. A conceptual nitrogen fate model was developed to provide remediation scientists and engineers with some practical guidelines in the use of ammonia-enhanced bioventing. Ammonia supplied to the subsurface dissolves readily in soil moisture and sorbs strongly to soil particles. The ammonium ion is the preferred nutrient form of many microorganisms. Some of the ammonia will be converted to nitrate by ammonia-oxidizing organisms. Field monitoring data from an operating ammonia-enhanced bioventing remediation site for diesel fuel contamination are presented. Conservative additions of ammonia promoted appreciable increases in evolved carbon dioxide and rate of oxygen utilization. An overabundance of added ammonia promoted formation of methane from likely anaerobic hydrocarbon degradation in the presence of nitrate as the electron acceptor

Advances in ammonia metabolism and hepatic encephalopathy

International Nuclear Information System (INIS)

Soeters, P.B.; Wilson, J.H.P.; Meijer, A.J.; Holm, E.

1988-01-01

There are four main 'parts' within the book: the first is devoted to peripheral and hepatic ammonia metabolism, the urea cycle, acid base status and its regulation; part two addresses animal models in liver failure, GABA-ergic neurotransmission and its relevance in hepatic failure; a third part concerns neurochemistry including brain ammonia metabolism, serotonin metabolism and energy status, in vivo evaluated with modern techniques like infusion of compounds labeled with stable or radioactive isotopes and with NMR, while the last section provides a description of the determination of ammonia and the treatment of encephalopathy with established but also with experimental techniques. refs.; figs.; tabs

Mydriatics release from solid and semi-solid ophthalmic formulations using different in vitro methods.

Science.gov (United States)

Pescina, Silvia; Macaluso, Claudio; Gioia, Gloria Antonia; Padula, Cristina; Santi, Patrizia; Nicoli, Sara

2017-09-01

The aim of the present paper was the development of semi-solid (hydrogels) and solid (film) ophthalmic formulations for the controlled release of two mydriatics: phenylephrine and tropicamide. The formulations - based on polyvinylalcohol and hyaluronic acid - were characterized, and release studies were performed with three different in vitro set-ups, i.e. Franz-type diffusion cell, vial method and inclined plane; for comparison, a solution and a commercial insert, both clinically used to induce mydriasis, were evaluated. Both gels and film allowed for a controlled release of drugs, appearing a useful alternative for mydriatics administration. However, the release kinetic was significantly influenced by the method used, highlighting the need for optimization and standardization of in vitro models for the evaluation of drug release from ophthalmic dosage forms.

Ice nucleation of ammonia gas exposed montmorillonite mineral dust particles

Directory of Open Access Journals (Sweden)

A. Salam

2007-07-01

Full Text Available The ice nucleation characteristics of montmorillonite mineral dust aerosols with and without exposure to ammonia gas were measured at different atmospheric temperatures and relative humidities with a continuous flow diffusion chamber. The montmorillonite particles were exposed to pure (100% and diluted ammonia gas (25 ppm at room temperature in a stainless steel chamber. There was no significant change in the mineral dust particle size distribution due to the ammonia gas exposure. 100% pure ammonia gas exposure enhanced the ice nucleating fraction of montmorillonite mineral dust particles 3 to 8 times at 90% relative humidity with respect to water (RHw and 5 to 8 times at 100% RHw for 120 min exposure time compared to unexposed montmorillonite within our experimental conditions. The percentages of active ice nuclei were 2 to 8 times higher at 90% RHw and 2 to 7 times higher at 100% RHw in 25 ppm ammonia exposed montmorillonite compared to unexposed montmorillonite. All montmorillonite particles are more efficient as ice nuclei with increasing relative humidities and decreasing temperatures. The activation temperature of montmorillonite exposed to 100% pure ammonia was 15°C higher than for unexposed montmorillonite particles at 90% RHw. In the 25 ppm ammonia exposed montmorillonite experiments, the activation temperature was 10°C warmer than unexposed montmorillonite at 90% RHw. Degassing does not reverse the ice nucleating ability of ammonia exposed montmorillonite mineral dust particles suggesting that the ammonia is chemically bound to the montmorillonite particle. This is the first experimental evidence that ammonia gas exposed montmorillonite mineral dust particles can enhance its activation as ice nuclei and that the activation can occur at temperatures warmer than –10°C where natural atmospheric ice nuclei are very scarce.

Colorimetric detection of ammonia using smartphones based on localized surface plasmon resonance of silver nanoparticles.

Science.gov (United States)

Amirjani, Amirmostafa; Fatmehsari, Davoud Haghshenas

2018-01-01

In this work, a rapid and straightforward method was developed for colorimetric determination of ammonia using smartphones. The mechanisms is based on the manipulation of the surface plasmon band of silver nanoparticles (AgNPs) via the formation of Ag (NH 3 ) 2 + complex. This complex decreases the amount of AgNPs in the solution and consequently, the color intensity of the colloidal system decreases. Not only the variation in color intensity of the solution can be tracked by a UV-vis spectrophotometer, but also a smartphone can be employed to monitor the color intensity variation by RGB analysis. Ammonia, in the concentration range of 10-1000mgL -1 , was successfully measured spectrophotometrically (UV-vis spectrophotometer) and colorimetrically (RGB measurement) with the detection limit of 180 and 200mgL -1 , respectively. Linear relationships were also developed for both methods. Also, the response time of the developed colorimetric sensor was around 20s. Both of the colorimetric and spectrophotometric methods showed a reliable performance for determination of ammonia in the real samples. Copyright © 2017 Elsevier B.V. All rights reserved.

Chilled Ammonia Process for CO2 Capture

DEFF Research Database (Denmark)

Darde, Victor Camille Alfred; Thomsen, Kaj; Well, Willy J.M. van

2010-01-01

The chilled ammonia process absorbs the CO2 at low temperature (2–10°C). The heat of absorption of carbon dioxide by ammonia is significantly lower than for amines. In addition, degradation problems can be avoided and a high carbon dioxide capacity is achieved. Hence, this process shows good...

Neutralization method for a hydrofluoric acid release

International Nuclear Information System (INIS)

Williams, D.L.; Deacon, L.E.

1976-01-01

A laboratory investigation of methods for neutralizing a release at the hydrofluoric acid tank farm at the Portsmouth Gaseous Diffusion Plant has revealed that the best neutralization method incorporates the use of a lime/water slurry. In this method, settling of suspended solids in the liquid is enhanced by the application of sodium dodecyl sulfate, which causes immediate flocculation and settling. Dilution and expulsion of the supernatant liquid above the flocculated solids result in an effluent which meets the one part per million fluoride limit established by the U.S. Environmental Protection Agency. A fluoride specific ion electrode is used to determine fluoride concentration. This method presently is being adapted for use in the hydrofluoric acid tank farm and is being considered for use at the plant's fluorine generation facility. It could be adapted for use in any facility that contains fluoride in aqueous solution

CuO mesostructures as ammonia sensors

Science.gov (United States)

Bhuvaneshwari, S.; Gopalakrishnan, N.

2018-04-01

The emission threshold of NH3 in air is 1000 kg/yr which is now about 20 Tg/yr according to environmental protection agencies. Hence, there is a rapid increase in need of NH3 sensors to timely detect and control NH3 emissions. Metal oxide nanostructures such as CuO with special features are potential candidates for NH3 sensing. In the present study, morphology controlled 3-dimensional CuO mesostructures were synthesized by surfactant-free hydrothermal method. A modified approach using a mixture of water and ethylene glycol (EG) was used as solvent to control the growth process. Hierarchical mesostructures namely, hollow-sphere-like and urchin-like feature with particle dimensions ranging from 0.3-1 µm were obtained by varying water/EG ratio. The room temperature ammonia sensing behavior of all samples was studied using an indigenous gas sensing set-up. It was found that hollow-sphere like CuO nanostructures showed a maximum response of 2 towards 300 ppm ammonia with a response and recovery time of 5 and 15 min. The hydrothermal synthesis strategy reported here has the advantage of producing shape controlled hierarchical materials are highly suitable for various technological applications.

Calcium in the Mechanism of Ammonia-Induced Astrocyte Swelling

Science.gov (United States)

Jayakumar, A.R.; Rao, K.V. Rama; Tong, X.Y; Norenberg, M.D.

2016-01-01

Brain edema, due largely to astrocyte swelling, is an important clinical problem in patients with acute liver failure. While mechanisms underlying astrocyte swelling in this condition are not fully understood, ammonia and associated oxidative/nitrosative stress (ONS) appear to be involved. Mechanisms responsible for the increase in reactive oxygen/nitrogen species (RONS) and their role in ammonia-induced astrocyte swelling, however, are poorly understood. Recent studies have demonstrated a transient increase in intracellular Ca2+ in cultured astrocytes exposed to ammonia. As Ca2+ is a known inducer of RONS, we investigated potential mechanisms by which Ca2+ may be responsible for the production of RONS and cell swelling in cultured astrocytes after treatment with ammonia. Exposure of cultured astrocytes to ammonia (5 mM) increased the formation of free radicals, including nitric oxide, and such increase was significantly diminished by treatment with the Ca2+ chelator BAPTA-AM. We then examined the activity of Ca2+-dependent enzymes that are known to generate RONS and found that ammonia significantly increased the activities of NADPH oxidase (NOX), constitutive nitric oxide synthase (cNOS) and phospholipase A2 (PLA2) and such increases in activity were significantly diminished by BAPTA. Pretreatment of cultures with 7-nitroindazole, apocyanin and quinacrine, respective inhibitors of cNOS, NOX and PLA2, all significantly diminished RONS production. Additionally, treatment of cultures with BAPTA or with inhibitors of cNOS, NOX and PLA2 reduced ammonia-induced astrocyte swelling. These studies suggest that the ammonia-induced rise in intracellular Ca2+ activates free radical producing enzymes that ultimately contribute to the mechanism of astrocyte swelling. PMID:19393035

Removal of Hg, As in FGD gypsum by different aqueous ammonia (amines) during CO2 sequestration.

Science.gov (United States)

Wenyi, Tan; Wenhui, Fan; Hongyi, Li; Zixin, Zhang; Yunkun, Zhu

2017-12-01

CO 2 sequestration by flue gas desulfurization gypsum (FGDG) has become a promising FGDG disposal technology due to simultaneous CO 2 emission reduction and FGDG conversion into calcium carbonate. In this paper, another merit of the novel technology, i.e., the removal of toxic elements (e.g., Hg and As) in FGDG, will be addressed for the first time. In three different aqueous ammonia (or amines) media, removal efficiencies of Hg and As in FGDG samples were evaluated during CO 2 sequestration. Higher than 90% and 20% removal efficiencies, respectively, for Hg and As are achieved at 40°C in aqueous ammonia media, but they decrease at elevated temperatures. Ammonia loss takes place at 80°C and pH varies greatly with temperatures in aqueous ammonia. This is disadvantageous for the formation of Hg-ammonia complexes and for the yield of carbonates, which are responsible for Hg or As re-adsorption. The sequential chemical extraction method suggests that the speciation changes of Hg are induced by FGDG carbonation, and that unstable Hg speciation in triethanolamine increases at elevated temperatures.

Surface Acoustic WaveAmmonia Sensors Based on ST-cut Quartz under Periodic Al Structure

Directory of Open Access Journals (Sweden)

Ming-Yau Su

2009-02-01

Full Text Available Surface acoustic wave (SAW devices are key components for sensing applications. SAW propagation under a periodic grating was investigated in this work. The theoretical method used here is the space harmonic method. We also applied the results of SAW propagation studied in this work to design a two-port resonator with an Al grating on ST-cut quartz. The measured frequency responses of the resonator were similar to the simulation ones. Then, the chemical interface of polyaniline/WO3 composites was coated on the SAW sensor for ammonia detection. The SAW sensor responded to ammonia gas and could be regenerated using dry nitrogen.

Novel ammonia sensor based on polyaniline/polylactic acid composite films

International Nuclear Information System (INIS)

Sotirov, S; Bodurov, I; Marudova, M

2017-01-01

We propose a new type of ammonia sensor based on composite film between polyaniline (emeraldine base) dissolved in dimethylformamide, and poly(DL-lactic) acid dissolved in chloroform. The two solutions were mixed in weight ratio of the components 1:1 and cast on Al 2 O 3 substrate, on which silver electrodes were deposited previously. The active layer structure and morphology were examined by atomic force microscopy. The sensor resistance at constant humidity and different ammonia concentrations was measured. It was found that an increase in the ammonia concentration leads to resistance increase. This result is explained in the terms of ionic interactions between the polyaniline and the ammonia, which change the permittivity of the sensor active media. A response between 2% and 590% was shown depending on the ammonia concentration. The sensor is reversible and possesses response time of typically 100 s. Based on the changes of the sensor resistance, ammonia concentration from 10 ppm to 1000 ppm could be detected. (paper)

Novel ammonia sensor based on polyaniline/polylactic acid composite films

Science.gov (United States)

Sotirov, S.; Bodurov, I.; Marudova, M.

2017-01-01

We propose a new type of ammonia sensor based on composite film between polyaniline (emeraldine base) dissolved in dimethylformamide, and poly(DL-lactic) acid dissolved in chloroform. The two solutions were mixed in weight ratio of the components 1:1 and cast on Al2O3 substrate, on which silver electrodes were deposited previously. The active layer structure and morphology were examined by atomic force microscopy. The sensor resistance at constant humidity and different ammonia concentrations was measured. It was found that an increase in the ammonia concentration leads to resistance increase. This result is explained in the terms of ionic interactions between the polyaniline and the ammonia, which change the permittivity of the sensor active media. A response between 2% and 590% was shown depending on the ammonia concentration. The sensor is reversible and possesses response time of typically 100 s. Based on the changes of the sensor resistance, ammonia concentration from 10 ppm to 1000 ppm could be detected.

Development of an Automated Diffusion Scrubber-Conductometry System for Measuring Atmospheric Ammonia

International Nuclear Information System (INIS)

Lee, Bok Young; Lee, Chong Keun; Lee, Dong Soo

2011-01-01

A semi-continuous and automated method for quantifying atmospheric ammonia at the parts per billion level has been developed. The instrument consists of a high efficiency diffusion scrubber, an electrolytic on-line anion exchange device, and a conductivity detector. Water soluble gases in sampled air diffuse through the porous membrane and are absorbed in an absorbing solution. Interferences are eliminated by using an anion exchange devises. The electrical conductivity of the solution is measured without chromatographic separation. The collection efficiency was over 99%. Over the 0-200 ppbv concentration range, the calibration was linear with r"2 = 0.99. The lower limit of detection was 0.09 ppbv. A parallel analysis of Seoul air over several days using this method and a diffusion scrubber coupled to an ion chromatography system showed acceptable agreement, r"2 = 0.940 (n = 686). This method can be applied for ambient air monitoring of ammonia

Ammonia nanotubes and their interactions with coinage metals

Energy Technology Data Exchange (ETDEWEB)

Mohajeri, Afshan, E-mail: amohajeri@shirazu.ac.ir; Bozorgizadeh, Tahereh

2014-09-30

Highlights: • The possibility of building ammonia nanotubes (ANTs) is explored. • Six ANTs formed by the stacks of 4- and 5-membered ammonia rings have been studied. • The interactions between the ANTs and coinage metals are investigated. • The nature of nitrogen–metal bonds is unveiled by quantum chemical approaches. - Abstract: The hydrogen bond networks of finite ammonia molecules are considered to explore the possibility of building ammonia nanotubes (ANTs). Six ANTs formed by the stacks of 4- and 5-membered ammonia rings have been studied. The calculated stabilization energies indicate considerable stability for ANTs. In the second part, the interactions between the constructed ANTs and coinage metals (M = Cu, Ag, and Au) are investigated with a focus on the nature of nitrogen…metal bonds. The changes in binding energies from copper to gold reveal that the three metals have almost similar tendency for the interaction with ANTs and the interaction strength is governed by the structure of ANT. Furthermore, the electronic and structural properties of the resulting complexes have been unveiled by means of the quantum chemical analyses. The N…M bonds are found to have partially covalent and partially electrostatic nature.

Free ammonia offers algal crop protection from predators in dairy wastewater and ammonium-rich media.

Science.gov (United States)

Thomas, Patrick K; Dunn, Gary P; Passero, Maxine; Feris, Kevin P

2017-11-01

Cost-effective methods for protecting crops from grazing organisms like rotifers are needed to reduce the risk of pond crashes in mass algal cultures. We present a novel strategy to optimize the exposure time to free ammonia, via control of media pH, in both defined media and dairy anaerobic digester effluent to suppress rotifers and maintain algal productivity. We tested five different free ammonia exposure times (0, 1, 2, 6, and 12h) and found a significant nonlinear effect of exposure time (p0.9) on rotifer survival. In both media types, 6-12h of elevated free ammonia significantly reduced Brachionus plicatilis rotifer survival with no negative effects on Nannochloropsis oculata, while shorter exposure times were insufficient to inhibit rotifers, leading to severe algal culture crashes. These results suggest that algal crops can be protected from rotifers, without productivity loss, by elevating free ammonia for 6 or more hours. Copyright © 2017 Elsevier Ltd. All rights reserved.

A novel XRF method to measure environmental release of copper and zinc from antifouling paints.

Science.gov (United States)

Ytreberg, Erik; Lagerström, Maria; Holmqvist, Albin; Eklund, Britta; Elwing, Hans; Dahlström, Magnus; Dahl, Peter; Dahlström, Mia

2017-06-01

The release of copper (Cu) and zinc (Zn) from vessels and leisure crafts coated with antifouling paints can pose a threat to water quality in semi-enclosed areas such as harbors and marinas as well as to coastal archipelagos. However, no reliable, practical and low-cost method exists to measure the direct release of metals from antifouling paints. Therefore, the paint industry and regulatory authorities are obliged to use release rate measurements derived from either mathematical models or from laboratory studies. To bridge this gap, we have developed a novel method using a handheld X-Ray Fluorescence spectrometer (XRF) to determine the cumulative release of Cu and Zn from antifouling paints. The results showed a strong linear relationship between XRF K α net intensities and metal concentrations, as determined by ICP-MS. The release of Cu and Zn were determined for coated panels exposed in harbors located in the Baltic Sea and in Kattegat. The field study showed salinity to have a strong impact on the release of Cu, i.e. the release increased with salinity. Contrary, the effect of salinity on Zn was not as evident. As exemplified in this work, the XRF method also makes it possible to identify the governing parameters to the release of Cu and Zn, e.g. salinity and type of paint formulation. Thus, the XRF method can be used to measure environmentally relevant releases of metallic compounds to design more efficient and optimized antifouling coatings. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Does ammonia trigger hyperventilation in the elasmobranch, Squalus acanthias suckleyi?

Science.gov (United States)

De Boeck, Gudrun; Wood, Chris M

2015-01-15

We examined the ventilatory response of the spiny dogfish, to elevated internal or environmental ammonia. Sharks were injected via arterial catheters with ammonia solutions or their Na salt equivalents sufficient to increase plasma total ammonia concentration [TAmm]a by 3-5 fold from 145±21μM to 447±150μM using NH4HCO3 and a maximum of 766±100μM using (NH4)2SO4. (NH4)2SO4 caused a small increase in ventilation frequency (+14%) and a large increase in amplitude (+69%), while Na2SO4 did not. However, CO2 partial pressure (PaCO2) also increased and arterial pHa and plasma bicarbonate concentration ([HCO3(-)]a) decreased. NH4HCO3 caused a smaller increase in plasma ammonia resulting in a smaller but significant, short lived increases in ventilation frequency (+6%) and amplitude (36%), together with a rise in PaCO2 and [HCO3(-)]a. Injection with NaHCO3 which increased pHa and [HCO3(-)]a did not change ventilation. Plasma ammonia concentration correlated significantly with ventilation amplitude, while ventilation frequency showed a (negative) correlation with pHa. Exposure to high environmental ammonia (1500μM NH4HCO3) did not induce changes in ventilation until plasma [TAmm]a increased and ventilation amplitude (but not frequency) increased in parallel. We conclude that internal ammonia stimulates ventilation in spiny dogfish, especially amplitude or stroke volume, while environmental ammonia only stimulates ventilation after ammonia diffuses into the bloodstream. Copyright © 2014 Elsevier B.V. All rights reserved.

Sustainable Ammonia Synthesis – Exploring the scientific challenges associated with discovering alternative, sustainable processes for ammonia production

Energy Technology Data Exchange (ETDEWEB)

Nørskov, Jens [Stanford Univ., CA (United States); ; SLAC National Accelerator Lab., Menlo Park, CA (United States); Chen, Jingguang [Columbia Univ., New York, NY (United States); Brookhaven National Lab. (BNL), Upton, NY (United States); Miranda, Raul [Dept. of Energy (DOE), Washington DC (United States). Office of Science; Fitzsimmons, Tim [Dept. of Energy (DOE), Washington DC (United States). Office of Science; Stack, Robert [Dept. of Energy (DOE), Washington DC (United States). Office of Science

2016-02-18

Ammonia (NH₃) is essential to all life on our planet. Until about 100 years ago, NH₃ produced by reduction of dinitrogen (N₂) in air came almost exclusively from bacteria containing the enzyme nitrogenase.. DOE convened a roundtable of experts on February 18, 2016. Participants in the Roundtable discussions concluded that the scientific basis for sustainable processes for ammonia synthesis is currently lacking, and it needs to be enhanced substantially before it can form the foundation for alternative processes. The Roundtable Panel identified an overarching grand challenge and several additional scientific grand challenges and research opportunities: -Discovery of active, selective, scalable, long-lived catalysts for sustainable ammonia synthesis. -Development of relatively low pressure (<10 atm) and relatively low temperature (<200 C) thermal processes. -Integration of knowledge from nature (enzyme catalysis), molecular/homogeneous and heterogeneous catalysis. -Development of electrochemical and photochemical routes for N₂ reduction based on proton and electron transfer -Development of biochemical routes to N₂ reduction -Development of chemical looping (solar thermochemical) approaches -Identification of descriptors of catalytic activity using a combination of theory and experiments -Characterization of surface adsorbates and catalyst structures (chemical, physical and electronic) under conditions relevant to ammonia synthesis.

Biotreatment of ammonia and butanal containing waste gases

OpenAIRE

Weckhuysen, B.M.; Vriens, L.; Verachtert, H.

1994-01-01

Abstract The biological removal of ammonia and butanal in contaminated air was investigated by using, respectively, a laboratory-scale filter and a scrubber-filter combination. It was shown that ammonia can be removed with an elimination efficiency of 83% at a volumetric load of 100 m3·m–2·h–1 with 4–16 ppm of ammonia. During the experiment percolates were analysed for nitrate, nitrite, ammonium and pH. It was found that the nitrification in the biofilter could deteriorate due to an inhibitio...

Catalytic synthesis of ammonia using vibrationally excited nitrogen

DEFF Research Database (Denmark)

Henriksen, Niels Engholm; Billing, Gert D.; Hansen, Flemming Yssing

1992-01-01

In a previous study we have considered the catalytic synthesis of ammonia in the presence of vibrationally excited nitrogen. The distribution over vibrational states was assumed to be maintained during the reaction, and it was shown that the yield of ammonia increased considerably compared...... to that from conventional synthesis. In the present study the nitrogen molecules are only excited at the inlet of a plug flow reactor, and the importance of vibrational relaxation is investigated. We show that vibrational excitation can give an enhanced yield of ammonia also in the situation where vibrational...

Ammonia concentration modeling based on retained gas sampler data

International Nuclear Information System (INIS)

Terrones, G.; Palmer, B.J.; Cuta, J.M.

1997-09-01

The vertical ammonia concentration distributions determined by the retained gas sampler (RGS) apparatus were modeled for double-shell tanks (DSTs) AW-101, AN-103, AN-104, and AN-105 and single-shell tanks (SSTs) A-101, S-106, and U-103. One the vertical transport of ammonia in the tanks were used for the modeling. Transport in the non-convective settled solids and floating solids layers is assumed to occur primarily via some type of diffusion process, while transport in the convective liquid layers is incorporated into the model via mass transfer coefficients based on empirical correlations. Mass transfer between the top of the waste and the tank headspace and the effects of ventilation of the headspace are also included in the models. The resulting models contain a large number of parameters, but many of them can be determined from known properties of the waste configuration or can be estimated within reasonable bounds from data on the waste samples themselves. The models are used to extract effective diffusion coefficients for transport in the nonconvective layers based on the measured values of ammonia from the RGS apparatus. The modeling indicates that the higher concentrations of ammonia seen in bubbles trapped inside the waste relative to the ammonia concentrations in the tank headspace can be explained by a combination of slow transport of ammonia via diffusion in the nonconvective layers and ventilation of the tank headspace by either passive or active means. Slow transport by diffusion causes a higher concentration of ammonia to build up deep within the waste until the concentration gradients between the interior and top of the waste are sufficient to allow ammonia to escape at the same rate at which it is being generated in the waste

Ammonia abundances in comets

Science.gov (United States)

Wyckoff, S.; Tegler, S.; Engel, L.

The emission band strengths of the NH2 bands of Comets Halley, Hartley-Good, Thiele, and Borrelly were measured to determine the NH2 column densities for the comets. Production rates obtained using the Haser and vectorial models are in agreement within the observational errors, suggesting that a simple two-step decay model may be used to approximate the NH2 distribution in a comet's coma. Ammonia-to-water abundance ratios from 0.01 to 0.4 percent were found for the four comets. The ratio in Comet Halley is found to be Q(NH3)/Q(H2O) = 0.002 + or - 0.001. No significant difference in the ammonia abundance was found before or after perihelion in Comet Halley.

Ammonia synthesis from first principles calculations

DEFF Research Database (Denmark)

Honkala, Johanna Karoliina; Hellman, Anders; Remediakis, Ioannis

2005-01-01

. When the size distribution of ruthenium particles measured by transmission electron microscopy was used as the [ink between the catalyst material and the theoretical treatment, the calculated rate was within a factor of 3 to 20 of the experimental rate. This offers hope for computer-based methods......The rate of ammonia synthesis over a nanoparticle ruthenium catalyst can be calculated directly on the basis of a quantum chemical treatment of the problem using density functional theory. We compared the results to measured rates over a ruthenium catalyst supported on magnesium aluminum spinet...

γ-irradiation induced zinc ferrites and their enhanced room-temperature ammonia gas sensing properties

Science.gov (United States)

Raut, S. D.; Awasarmol, V. V.; Ghule, B. G.; Shaikh, S. F.; Gore, S. K.; Sharma, R. P.; Pawar, P. P.; Mane, R. S.

2018-03-01

Zinc ferrite (ZnFe2O4) nanoparticles (NPs), synthesized using a facile and cost-effective sol-gel auto-combustion method, were irradiated with 2 and 5 kGy γ-doses using 60Co as a radioactive source. Effect of γ-irradiation on the structure, morphology, pore-size and pore-volume and room-temperature (300 K) gas sensor performance has been measured and reported. Both as-synthesized and γ-irradiated ZnFe2O4 NPs reveal remarkable gas sensor activity to ammonia in contrast to methanol, ethanol, acetone and toluene volatile organic gases. The responses of pristine, 2 and 5 kGy γ-irradiated ZnFe2O4 NPs are respectively 55%, 66% and 81% @100 ppm concentration of ammonia, signifying an importance of γ-irradiation for enhancing the sensitivity, selectivity and stability of ZnFe2O4 NPs as ammonia gas sensors. Thereby, due to increase in surface area and crystallinity on γ-doses, the γ-irradiation improves the room-temperature ammonia gas sensing performance of ZnFe2O4.

Metabolic fate of 13N-labeled ammonia in rat brain

International Nuclear Information System (INIS)

Cooper, A.J.L.; McDonald, J.M.; Gelbard, A.S.; Gledhill, R.F.; Duffy, T.E.

1979-01-01

After infusion of physiological concentrations of [ 13 N]ammonia for 10 min via one internal carotid artery, the relative specific activities of glutamate, glutamine (α-amino), and glutamine (amide) in rat brain were approximately 1:5:400, respectively. Analysis of metabolites, after infusion of [ 13 N]ammonia into one lateral cerebral ventricle, indicated that ammonia entering the brain from the cerebrospinal fluid is also metabolized in a small glutamate pool. Pretreatment with methionine sulfoximine led to a decrease in the label present in brain glutamine following carotid artery infusion of [ 13 N]ammonia. 13 N activity in brain glutamate was greater than in the α-amino group of glutamine. The amount of label recovered in the right cerebral hemisphere, 5 s after a rapid bolus injection of [ 13 N]ammonia via the right common carotid artery, was independent of concentration within the bolus over a 1000-fold range indicating that ammonia enters the brain largely by diffusion. In normal rats approximately 60% of the label recovered in brain was incorporated into glutamine, indicating that the t 1 /sub// 2 for conversion of ammonia to glutamine in the small pool is in the range of 1 to 3 s or less. The data emphasize the importance of the small pool glutamine synthetase as a metabolic trap for the detoxification of blood-borne and endogenously produced brain ammonia. The possibility that the astrocytes represent the anatomical site of the small pool is considered

EMRP JRP MetNH3: Towards a Consistent Metrological Infrastructure for Ammonia Measurements in Ambient Air

Science.gov (United States)

Leuenberger, Daiana; Balslev-Harder, David; Braban, Christine F.; Ebert, Volker; Ferracci, Valerio; Gieseking, Bjoern; Hieta, Tuomas; Martin, Nicholas A.; Pascale, Céline; Pogány, Andrea; Tiebe, Carlo; Twigg, Marsailidh M.; Vaittinen, Olavi; van Wijk, Janneke; Wirtz, Klaus; Niederhauser, Bernhard

2016-04-01

Measuring ammonia in ambient air is a sensitive and priority issue due to its harmful effects on human health and ecosystems. In addition to its acidifying effect on natural waters and soils and to the additional nitrogen input to ecosystems, ammonia is an important precursor for secondary aerosol formation in the atmosphere. The European Directive 2001/81/EC on "National Emission Ceilings for Certain Atmospheric Pollutants (NEC)" regulates ammonia emissions in the member states. However, there is a lack of regulation regarding certified reference material (CRM), applicable analytical methods, measurement uncertainty, quality assurance and quality control (QC/QA) procedures as well as in the infrastructure to attain metrological traceability. As shown in a key comparison in 2007, there are even discrepancies between reference materials provided by European National Metrology Institutes (NMIs) at amount fraction levels up to three orders of magnitude higher than ambient air levels. MetNH3 (Metrology for ammonia in ambient air), a three-year project that started in June 2014 in the framework of the European Metrology Research Programme (EMRP), aims to reduce the gap between requirements set by the European emission regulations and state-of-the-art of analytical methods and reference materials. The overarching objective of the JRP is to achieve metrological traceability for ammonia measurements in ambient air from primary certified reference material CRM and instrumental standards to the field level. This requires the successful completion of the three main goals, which have been assigned to three technical work packages: To develop improved reference gas mixtures by static and dynamic gravimetric generation methods Realisation and characterisation of traceable preparative calibration standards (in pressurised cylinders as well as mobile generators) of ammonia amount fractions similar to those in ambient air based on existing methods for other reactive analytes. The

Proximal tubule-specific glutamine synthetase deletion alters basal and acidosis-stimulated ammonia metabolism

Science.gov (United States)

Lee, Hyun-Wook; Osis, Gunars; Handlogten, Mary E.; Lamers, Wouter H.; Chaudhry, Farrukh A.; Verlander, Jill W.

2016-01-01

Glutamine synthetase (GS) catalyzes the recycling of NH4+ with glutamate to form glutamine. GS is highly expressed in the renal proximal tubule (PT), suggesting ammonia recycling via GS could decrease net ammoniagenesis and thereby limit ammonia available for net acid excretion. The purpose of the present study was to determine the role of PT GS in ammonia metabolism under basal conditions and during metabolic acidosis. We generated mice with PT-specific GS deletion (PT-GS-KO) using Cre-loxP techniques. Under basal conditions, PT-GS-KO increased urinary ammonia excretion significantly. Increased ammonia excretion occurred despite decreased expression of key proteins involved in renal ammonia generation. After the induction of metabolic acidosis, the ability to increase ammonia excretion was impaired significantly by PT-GS-KO. The blunted increase in ammonia excretion occurred despite greater expression of multiple components of ammonia generation, including SN1 (Slc38a3), phosphate-dependent glutaminase, phosphoenolpyruvate carboxykinase, and Na+-coupled electrogenic bicarbonate cotransporter. We conclude that 1) GS-mediated ammonia recycling in the PT contributes to both basal and acidosis-stimulated ammonia metabolism and 2) adaptive changes in other proteins involved in ammonia metabolism occur in response to PT-GS-KO and cause an underestimation of the role of PT GS expression. PMID:27009341

Digital processing method for monitoring the radioactivity of stack releases

International Nuclear Information System (INIS)