Activity of Cu-activated carbon fiber catalyst in wet oxidation of ammonia solution

International Nuclear Information System (INIS)

Hung, Chang-Mao

2009-01-01

Aqueous solutions of 200-1000 mg/L of ammonia were oxidized in a trickle-bed reactor using Cu-activated carbon fiber (ACF) catalysts, which were prepared by incipient wet impregnation with aqueous solutions of copper nitrate that was deposited on ACF substrates. The results reveal that the conversion of ammonia by wet oxidation in the presence of Cu-ACF catalysts was a function of the metal loading weight ratio of the catalyst. The total conversion efficiency of ammonia was 95% during wet oxidation over the catalyst at 463 K at an oxygen partial pressure of 3.0 MPa. Moreover, the effect of the initial concentration of ammonia and the reaction temperature on the removal of ammonia from the effluent streams was also studied at a liquid space velocity of less than 3.0 h -1 .

[INVITED] Porphyrin-nanoassembled fiber-optic gas sensor fabrication: Optimization of parameters for sensitive ammonia gas detection

Science.gov (United States)

Korposh, Sergiy; Kodaira, Suguru; Selyanchyn, Roman; Ledezma, Francisco H.; James, Stephen W.; Lee, Seung-Woo

2018-05-01

Highly sensitive fiber-optic ammonia gas sensors were fabricated via layer-by-layer deposition of poly(diallyldimethylammonium chloride) (PDDA) and tetrakis(4-sulfophenyl)porphine (TSPP) onto the surface of the core of a hard-clad multimode fiber that was stripped of its polymer cladding. The effects of film thickness, length of sensing area, and depth of evanescent wave penetration were investigated to clearly understand the sensor performance. The sensitivity of the fiber-optic sensor to ammonia was linear in the concentration range of 0.5-50 ppm and the response and recovery times were less than 3 min, with a limit of detection of 0.5 ppm, when a ten-cycle PDDA/TSPP film was assembled on the surface of the core along a 1 cm-long stripped section of the fiber. The sensor's response towards ammonia was also checked under different relative humidity conditions and a simple statistical data treatment approach, principal component analysis, demonstrated the feasibility of ammonia sensing in environmental relative humidity ranging from dry 7% to highly saturated 80%. Penetration depths of the evanescent wave for the optimal sensor configuration were estimated to be 30 and 33 nm at wavelengths of 420 and 706 nm, which are in a good agreement with the thickness of the 10-cycle deposited film (ca. 30 nm).

Activity of Cu-activated carbon fiber catalyst in wet oxidation of ammonia solution

Energy Technology Data Exchange (ETDEWEB)

Hung, Chang-Mao, E-mail: hungcm1031@gmail.com [Department of Industry Engineering and Management, Yung-Ta Institute of Technology and Commerce, 316 Chung-shan Road, Linlo, Pingtung 909, Taiwan (China)

2009-07-30

Aqueous solutions of 200-1000 mg/L of ammonia were oxidized in a trickle-bed reactor using Cu-activated carbon fiber (ACF) catalysts, which were prepared by incipient wet impregnation with aqueous solutions of copper nitrate that was deposited on ACF substrates. The results reveal that the conversion of ammonia by wet oxidation in the presence of Cu-ACF catalysts was a function of the metal loading weight ratio of the catalyst. The total conversion efficiency of ammonia was 95% during wet oxidation over the catalyst at 463 K at an oxygen partial pressure of 3.0 MPa. Moreover, the effect of the initial concentration of ammonia and the reaction temperature on the removal of ammonia from the effluent streams was also studied at a liquid space velocity of less than 3.0 h{sup -1}.

Effect of Aqueous Ammonia Soaking on the methane yield and composition of digested manure fibers applying different ammonia concentrations and treatment durations

DEFF Research Database (Denmark)

Mirtsou-Xanthopoulou, Chrysoula; Jurado, Esperanza; Skiadas, Ioannis

2014-01-01

, their economical profitable operation relies on increasing the methane yield from manure, and especially of its solid fraction which is not so easily degradable. In the present study, Aqueous Ammonia Soaking (AAS) in six different concentrations in ammonia (5%, 10%, 15%, 20%, 25% and 32%) and for 1, 3 and 5 days...... at 22°C was applied on digested fibers separated from the effluent of a manure-fed, full-scale anaerobic digester. A methane yield increase from 76% to 104% was achieved during the first series of experiments, while the difference in reagent concentration did not considerably affect the methane yield...... is a very promising treatment resulting to an overall increase of the methane yield of digested manure fibers from 76 to 265% depending on the conditions and the batch of digested fibers used (an even higher increase of 190-265% was achieved during the 2nd series of experiments, where different AAS...

Effects of aqueous ammonia treatment on fiber’s surface morphology and enzymatic digestibility of empty fruit bunch fiber (EFBF)

International Nuclear Information System (INIS)

Ling, Tang Pei; Hassan, Osman

2013-01-01

This study was conducted to investigate the effects of aqueous ammonia reflux and soaked treatment on the fiber’s surface morphology and enzymatic digestibility of empty fruit bunch fiber (EFBF). The surface morphological changes of the fiber after aqueous ammonia treatment was linked to the sugars yield by enzymatic hydrolysis. The effectiveness of 6.25% aqueous ammonia treatment in improving enzymatic digestibility of EFBF was initially studied in reflux system and by soaking. The results showed that soaked treatment was more effective than reflux system. Further study on soaked treatment of EFBF was carried out by increasing the ammonia concentration to 12.50%. Soaking in aqueous ammonia was conducted at 30°C and 50°C for 24 hours. The results of enzymatic hydrolysis showed that sugar yield from EFBF soaked in 12.50% aqueous ammonia at 50°C was the highest. Approximately 242.91±15.50 mg/g EFBF of xylose and 320.49±28.31 mg/g EFBF of glucose were produced by the action of enzyme Cellic Ctec 2. Results of scanning electron microscopic showed that aqueous ammonia treatment by soaking had caused a more severe structural distortion on the fiber’s surface and higher removal of silica bodies that embedded on the fiber than those in reflux system. The changes on the fiber’s surface morphology were believed is the contributing factor that improved the enzymatic digestibility of EFBF after aqueous ammonia treatment

Effects of aqueous ammonia treatment on fiber’s surface morphology and enzymatic digestibility of empty fruit bunch fiber (EFBF)

Energy Technology Data Exchange (ETDEWEB)

Ling, Tang Pei; Hassan, Osman [Department of Food Science, School of Chemical Science and Food Technology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi UKM, Selangor (Malaysia)

2013-11-27

This study was conducted to investigate the effects of aqueous ammonia reflux and soaked treatment on the fiber’s surface morphology and enzymatic digestibility of empty fruit bunch fiber (EFBF). The surface morphological changes of the fiber after aqueous ammonia treatment was linked to the sugars yield by enzymatic hydrolysis. The effectiveness of 6.25% aqueous ammonia treatment in improving enzymatic digestibility of EFBF was initially studied in reflux system and by soaking. The results showed that soaked treatment was more effective than reflux system. Further study on soaked treatment of EFBF was carried out by increasing the ammonia concentration to 12.50%. Soaking in aqueous ammonia was conducted at 30°C and 50°C for 24 hours. The results of enzymatic hydrolysis showed that sugar yield from EFBF soaked in 12.50% aqueous ammonia at 50°C was the highest. Approximately 242.91±15.50 mg/g EFBF of xylose and 320.49±28.31 mg/g EFBF of glucose were produced by the action of enzyme Cellic Ctec 2. Results of scanning electron microscopic showed that aqueous ammonia treatment by soaking had caused a more severe structural distortion on the fiber’s surface and higher removal of silica bodies that embedded on the fiber than those in reflux system. The changes on the fiber’s surface morphology were believed is the contributing factor that improved the enzymatic digestibility of EFBF after aqueous ammonia treatment.

ADM1-based modeling of anaerobic digestion of swine manure fibers pretreated with aqueous ammonia soaking

DEFF Research Database (Denmark)

Jurado, Esperanza; Gavala, Hariklia N.; Skiadas, Ioannis

2012-01-01

fibers. In the present study, mesophilic anaerobic digestion of AAS pretreated manure fibers was tested in CSTR-type digesters fed with swine manure and/or a mixture of swine manure and AAS pretreated manure fibers. The Anaerobic Digestion Model No.1 (ADM1) was used for the prediction of the effect......Anaerobic digestion of manure fibers present challenges due to their low biodegradability. Aqueous ammonia soaking (AAS) and subsequent ammonia removal has been tested as a simple and cheap method to disrupt the lignocellulose and increase the methane potential and the biogas productivity of manure...... that the AAS had on the efficiency of the anaerobic digestion of manure. Kinetic parameters were estimated by fitting of the model to data from manure fed digesters. The model was able to satisfactorily simulate the behaviour of digesters fed with manure. However, the model predictions were poorer...

Decreasing ammonia inhibition in thermophilic methanogenic bioreactors using carbon fiber textiles.

Science.gov (United States)

Sasaki, Kengo; Morita, Masahiko; Hirano, Shin-ichi; Ohmura, Naoya; Igarashi, Yasuo

2011-05-01

Ammonia accumulation is one of the main causes of the loss of methane production observed during fermentation. We investigated the effect of addition of carbon fiber textiles (CFT) to thermophilic methanogenic bioreactors with respect to ammonia tolerance during the process of degradation of artificial garbage slurry, by comparing the performance of the reactors containing CFT with the performance of reactors without CFT. Under total ammonia-N concentrations of 3,000 mg L(-1), the reactors containing CFT were found to mediate stable removal of organic compounds and methane production. Under these conditions, high levels of methanogenic archaea were retained at the CFT, as determined by 16S rRNA gene analysis for methanogenic archaea. In addition, Methanobacterium sp. was found to be dominant in the suspended fraction, and Methanosarcina sp. was dominant in the retained fraction of the reactors with CFT. However, the reactors without CFT had lower rates of removal of organic compounds and production of methane under total ammonia-N concentrations of 1,500 mg L(-1). Under this ammonia concentration, a significant accumulation of acetate was observed in the reactors without CFT (130.0 mM), relative to the reactors with CFT (4.2 mM). Only Methanobacterium sp. was identified in the reactors without CFT. These results suggest that CFT enables stable proliferation of aceticlastic methanogens by preventing ammonia inhibition. This improves the process of stable garbage degradation and production of methane in thermophilic bioreactors that include high levels of ammonia.

Strength behaviour of kerosene coated coir fiber-reinforced expansive soil

OpenAIRE

Ramasubbarao Godavarthi Venkata

2014-01-01

Coir fibers are extracted from the husks surrounding the coconut. Coir fibers can be effectively used as reinforcing material but it has less durability and hence coir fiber coated with kerosene is used as reinforcement in the present study. The objective of the present investigation is to study the strength behavior of expansive soil reinforced with 5mm long randomly distributed kerosene coated coir fibers in 0% (unreinforced), 0.5%, 1% and 1.5% by dry wei...

Transverse thermal expansion of carbon fiber/epoxy matrix composites

Science.gov (United States)

Helmer, J. F.; Diefendorf, R. J.

1983-01-01

Thermal expansion coefficients and moduli of elasticity have been determined experimentally for a series of epoxy-matrix composites reinforced with carbon and Kevlar fibers. It is found that in the transverse direction the difference between the properties of the fiber and the matrix is not as pronounced as in the longitudinal direction, where the composite properties are fiber-dominated. Therefore, the pattern of fiber packing tends to affect transverse composite properties. The transverse properties of the composites tested are examined from the standpoint of the concept of homogeneity defined as the variation of packing (or lack thereof) throughout a sample.

Effects of fibers on expansive shotcrete mixtures consisting of calcium sulfoaluminate cement, ordinary Portland cement, and calcium sulfate

Directory of Open Access Journals (Sweden)

H. Yu

2018-04-01

Full Text Available The mining industry often uses shotcrete for ground stabilization. However, cracking within shotcrete is commonly observed, which delays production schedules and increases maintenance costs. A possible crack reduction method is using expansive shotcrete mixture consisting of calcium sulfoaluminate cement (CSA, ordinary Portland cement (OPC, and calcium sulfate (CS to reduce shrinkage. Furthermore, fibers can be added to the mixture to restrain expansion and impede cracking. The objective of this paper is to study the effects of nylon fiber, glass fiber, and steel fiber on an expansive shotcrete mixture that can better resist cracking. In this study, parameters such as density, water absorption, volume of permeable voids, unconfined compressive strength (UCS, splitting tensile strength (STS, and volume change of fiber-added expansive mixtures were determined at different time periods (i.e. the strengths on the 28th day, and the volume changes on the 1st, 7th, 14th, 21st, and 28th days. The results show that addition of fibers can improve mixture durability, in the form of decreased water absorption and reduced permeable pore space content. Moreover, the expansion of the CSA-OPC-CS mixture was restrained up to 50% by glass fiber, up to 43% by nylon fiber, and up to 28% by steel fiber. The results show that the STS was improved by 57% with glass fiber addition, 43% with steel fiber addition, and 38% with nylon fiber addition. The UCS was also increased by 31% after steel fiber addition, 26% after nylon fiber addition, and 16% after glass fiber addition. These results suggest that fiber additions to the expansive shotcrete mixtures can improve durability and strengths while controlling expansion. Keywords: Shotcrete, Restrained expansion, Fibers, Calcium sulfoaluminate cement (CSA, Ordinary Portland cement (OPC, Calcium sulfate (CS

Fiber Optic Microcantilever Sensor Coupled with Reactive Polymers for Vapor Phase Detection of Ammonia, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Luna Innovations proposes to adapt its current aqueous-based, fiber-optic microcantilever sensor technology for real-time, monitoring of ammonia in air. Phase I...

Ammonia gas sensing property of gadolinium oxide using fiber optic gas sensor

Science.gov (United States)

Kumar, J. Santhosh; Ranganathan, B.; Sastikumar, D.

2017-05-01

The design of fiber optic sensor is based on a cladding modification methodology. A fiber-optic chemical sensor is developed by replacing a certain portion of the original cladding with a chemically sensitive material, specifically, calcinated gadolinium oxide (Gd2O3).Both the light absorption co-efficient and refractive index change upon exposure to chemical vapours of volatile organic compounds (VOCs) such as ammonia (NH3), ethanol (CH3CH2OH), and methanol (CH3OH). The spectral characteristics of the sensor were studied for different concentrations ranging from 0-500 ppm. These changes induced the optical intensity modulation of the transmitted optical signal. During interaction between the sensing material and VOCs, the output intensity is taken into account to detect the toxic VOCs present in the environment. This was systematically investigated by X-ray diffractometer (XRD) and SEM. The XRD analysis indicated that the calcinated Gd2O3 was formed in cubic structure with the crystallite size of 13 nm. The Gd2O3 nanorods with thickness ranging from 80 to 120 nm were confirmed from SEM. The ammonia gas response of the Gd2O3 sensor is presented. A model is proposed for understanding the spectral intensity variations.

Adsorption of sulfur dioxide on ammonia-treated activated carbon fibers

Science.gov (United States)

Mangun, C.L.; DeBarr, J.A.; Economy, J.

2001-01-01

A series of activated carbon fibers (ACFs) and ammonia-treated ACFs prepared from phenolic fiber precursors have been studied to elucidate the role of pore size, pore volume, and pore surface chemistry on adsorption of sulfur dioxide and its catalytic conversion to sulfuric acid. As expected, the incorporation of basic functional groups into the ACFs was shown as an effective method for increasing adsorption of sulfur dioxide. The adsorption capacity for dry SO2 did not follow specific trends; however the adsorption energies calculated from the DR equation were found to increase linearly with nitrogen content for each series of ACFs. Much higher adsorption capacities were achieved for SO2 in the presence of oxygen and water due to its catalytic conversion to H2SO4. The dominant factor for increasing adsorption of SO2 from simulated flue gas for each series of fibers studied was the weight percent of basic nitrogen groups present. In addition, the adsorption energies calculated for dry SO2 were shown to be linearly related to the adsorption capacity of H2SO4 from this flue gas for all fibers. It was shown that optimization of this parameter along with the pore volume results in higher adsorption capacities for removal of SO2 from flue gases. ?? 2001 Elsevier Science Ltd. All rights reserved.

Optimization of Aqueous Ammonia Soaking of manure fibers by Response Surface Methodology for unlocking the methane potential of swine manure

DEFF Research Database (Denmark)

Lymperatou, Anna; Gavala, Hariklia N.; Skiadas, Ioannis

2017-01-01

Swine manure mono-digestion often results to economically non-feasible processes, due to the high dilution and ammonia concentration together with the low degradation rates it presents. The effects of different parameters of Aqueous Ammonia Soaking (AAS) as a pretreatment for improving...... to be optimal (7% w/w NH3, 96 hours, and 0.16 kg/l) in combination to a significant increase of the short term CH4 yield (244% in 17 days), make this pretreatment a promising solution for improving swine manure mono-digestion. Furthermore, compositional analysis of the manure fibers revealed significant...... the digestion of manure fibers when coupled to an ammonia removal step were investigated in this study. Response Surface Methodology was followed and the influence and interactions of the following AAS parameters were studied: NH3 concentration, duration and solid-to-liquid ratio. The mild conditions found...

Brillouin Corrosion Expansion Sensors for Steel Reinforced Concrete Structures Using a Fiber Optic Coil Winding Method

Directory of Open Access Journals (Sweden)

Xingjun Lv

2011-11-01

Full Text Available In this paper, a novel kind of method to monitor corrosion expansion of steel rebars in steel reinforced concrete structures named fiber optic coil winding method is proposed, discussed and tested. It is based on the fiber optical Brillouin sensing technique. Firstly, a strain calibration experiment is designed and conducted to obtain the strain coefficient of single mode fiber optics. Results have shown that there is a good linear relationship between Brillouin frequency and applied strain. Then, three kinds of novel fiber optical Brillouin corrosion expansion sensors with different fiber optic coil winding packaging schemes are designed. Sensors were embedded into concrete specimens to monitor expansion strain caused by steel rebar corrosion, and their performance was studied in a designed electrochemical corrosion acceleration experiment. Experimental results have shown that expansion strain along the fiber optic coil winding area can be detected and measured by the three kinds of sensors with different measurement range during development the corrosion. With the assumption of uniform corrosion, diameters of corrosion steel rebars were obtained using calculated average strains. A maximum expansion strain of 6,738 με was monitored. Furthermore, the uniform corrosion analysis model was established and the evaluation formula to evaluate mass loss rate of steel rebar under a given corrosion rust expansion rate was derived. The research has shown that three kinds of Brillouin sensors can be used to monitor the steel rebar corrosion expansion of reinforced concrete structures with good sensitivity, accuracy and monitoring range, and can be applied to monitor different levels of corrosion. By means of this kind of monitoring technique, quantitative corrosion expansion monitoring can be carried out, with the virtues of long durability, real-time monitoring and quasi-distribution monitoring.

Brillouin corrosion expansion sensors for steel reinforced concrete structures using a fiber optic coil winding method.

Science.gov (United States)

Zhao, Xuefeng; Gong, Peng; Qiao, Guofu; Lu, Jie; Lv, Xingjun; Ou, Jinping

2011-01-01

In this paper, a novel kind of method to monitor corrosion expansion of steel rebars in steel reinforced concrete structures named fiber optic coil winding method is proposed, discussed and tested. It is based on the fiber optical Brillouin sensing technique. Firstly, a strain calibration experiment is designed and conducted to obtain the strain coefficient of single mode fiber optics. Results have shown that there is a good linear relationship between Brillouin frequency and applied strain. Then, three kinds of novel fiber optical Brillouin corrosion expansion sensors with different fiber optic coil winding packaging schemes are designed. Sensors were embedded into concrete specimens to monitor expansion strain caused by steel rebar corrosion, and their performance was studied in a designed electrochemical corrosion acceleration experiment. Experimental results have shown that expansion strain along the fiber optic coil winding area can be detected and measured by the three kinds of sensors with different measurement range during development the corrosion. With the assumption of uniform corrosion, diameters of corrosion steel rebars were obtained using calculated average strains. A maximum expansion strain of 6,738 με was monitored. Furthermore, the uniform corrosion analysis model was established and the evaluation formula to evaluate mass loss rate of steel rebar under a given corrosion rust expansion rate was derived. The research has shown that three kinds of Brillouin sensors can be used to monitor the steel rebar corrosion expansion of reinforced concrete structures with good sensitivity, accuracy and monitoring range, and can be applied to monitor different levels of corrosion. By means of this kind of monitoring technique, quantitative corrosion expansion monitoring can be carried out, with the virtues of long durability, real-time monitoring and quasi-distribution monitoring.

Enhanced methane productivity from swine manure fibers by aqueous ammonia soaking pretreatment

DEFF Research Database (Denmark)

Jurado, Esperanza; Skiadas, Ioannis; Gavala, Hariklia N.

2011-01-01

The necessity of increasing the methane productivity of manure based biogas plants has triggered the development of new separation technologies for being applied before anaerobic digestion of the manure. Thus, manure solid and liquid fractions could be used to centralized biogas plants for methane...... production and as fertilizer on the farm, respectively. One of the challenges of this approach is that the solid fraction of manure contains lignocellulosic fibers, which are difficult to digest and thus make anaerobic digestion process slow and economically unfavourable. In the present study, aqueous...... ammonia soaking (AAS) was investigated as a pretreatment method to disrupt lignocellulosic structure and increase methane potential of swine manure fibers. It was proven that AAS broke down the lignocellulosic structure dissolving approximately the 35% of lignin and maintaining cellulose...

A fiber optic ammonia sensor using a universal pH indicator

OpenAIRE

Rodríguez Rodríguez, Adolfo Josué; Domínguez Cruz, Rene F.; May Arrioja, Daniel A.; Ruiz Zamarreño, Carlos; Matías Maestro, Ignacio; Arregui San Martín, Francisco Javier

2014-01-01

A universal pH indicator is used to fabricate a fiber optic ammonia sensor. The advantage of this pH indicator is that it exhibits sensitivity toammonia over a broad wavelength range. This provides a differential response, with a valley around 500 nm and a peak around 650 nm, which allows us to perform ratiometric measurements. The ratiometric measurements provide not only an enhanced signal, but can also eliminate any external disturbance due to humidity or temperature fluctuations. In addit...

Optimization of Aqueous Ammonia Soaking of manure fibers by Response Surface Methodology for unlocking the methane potential of swine manure.

Science.gov (United States)

Lymperatou, Anna; Gavala, Hariklia N; Skiadas, Ioannis V

2017-11-01

Swine manure mono-digestion often results to economically non-feasible processes, due to the high dilution and ammonia concentration together with the low degradation rates it presents. The effects of different parameters of Aqueous Ammonia Soaking (AAS) as a pretreatment for improving the digestion of manure fibers when coupled to an ammonia removal step were investigated in this study. Response Surface Methodology was followed and the influence and interactions of the following AAS parameters were studied: NH 3 concentration, duration and solid-to-liquid ratio. The mild conditions found to be optimal (7%w/w NH 3 , 96h, and 0.16kg/L) in combination to a significant increase of the short term CH 4 yield (244% in 17days), make this pretreatment a promising solution for improving swine manure mono-digestion. Furthermore, compositional analysis of the manure fibers revealed significant solubilization of hemicellulose, while no lignin removal or loss of cellulose occurred under optimal conditions. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Optical Fiber Sensors For Monitoring Joint Articulation And Chest Expansion Of A Human Body

Science.gov (United States)

Muhs, Jeffrey D.; Allison, Stephen W.

1997-12-23

Fiber-optic sensors employing optical fibers of elastomeric material are incorporated in devices adapted to be worn by human beings in joint and chest regions for the purpose of monitoring and measuring the extent of joint articulation and chest expansion especially with respect to time.

On the effect of aqueous ammonia soaking pretreatment on batch and continuous anaerobic digestion of digested swine manure fibers

DEFF Research Database (Denmark)

Mirtsou Xanthopoulou, Chrysoula; Jurado, Esperanza; Skiadas, Ioannis

2012-01-01

, their economical profitable operation relies on increasing the methane yield from manure, and especially of its solid fraction which is not so easily degradable. Aqueous Ammonia Soaking (AAS) has been successfully applied on digested fibers separated from the effluent of a manure-fed, full-scale anaerobic digester......-pretreated digested manure fibers on the kinetics of anaerobic digestion process. It was found that AAS treatment had a profound effect mainly on the hydrolysis rate of particulate carbohydrates....

Continuous anaerobic digestion of swine manure: ADM1-based modelling and effect of addition of swine manure fibers pretreated with aqueous ammonia soaking

OpenAIRE

Jurado, E.; Antonopoulou, G.; Lyberatos, G.; Gavala, Hariklia N.; Skiadas, Ioannis V.

2016-01-01

Anaerobic digestion of manure fibers presents challenges due to their low biodegradability. Aqueous ammonia soaking (AAS) has been tested as a simple method to disrupt the lignocellulose and increase the methane yield of manure fibers. In the present study, mesophilic anaerobic digestion of AAS pretreated manure fibers was performed in CSTR-type digesters, fed with swine manure and/or a mixtureof swine manure and AAS pretreated manure fibers (at a total solids based ratio of 0.52 manure per0....

Fiber Optic Detection of Ammonia Gas

Directory of Open Access Journals (Sweden)

L. Kalvoda

2006-01-01

Full Text Available Bathochromic shifts accompanying the formation of several bivalent metallic complexes containing 5-(4’-dimethylaminophenylimino quinolin-8-one (L1, and 7-chlore-5(4’-diethylamino-2-methylphenylimino quinolin-8-one (L2 ligands in ethanol solutions were evaluated by VIS-NIR spectroscopy. The [L1-Cu-L1] sulphide complex was selected as a reagent for further tests on optical fibres. Samples of multimode siloxane-clad fused-silica fibre were sensitized by diffusing an ethanol/chloroform solution of the dye into the cladding polymer, and tested by VIS-NIR optical spectroscopy (12 cm long fibre sections, and optical time domain reflectometry (OTDR; 20 ns laser pulses, wavelength 850 nm, 120 m long fibre sensitized within the interval 104–110 m. A well-resolved absorption band of the reagent could be identified in the absorption spectra of the fibres. After exposure to dry ammonia/nitrogen gas with increasing ammonia concentration (0–4000 ppm, the short fibre samples showed subsequent decay of NIR optical absorption; saturation was observed for higher ammonia levels. The concentration resolution r ? 50 ppm and forward response time t90 ? 30 sec were obtained within the interval 0–1000 ppm. The OTDR courses showed an enhancement of the back-scattered light intensity coming from the sensitized region after diffusion of the initial reagent, and decay after exposure to concentrated ammonia/nitrogen gas (10000 ppm.

Mutation types and aging differently affect revertant fiber expansion in dystrophic mdx and mdx52 mice.

Directory of Open Access Journals (Sweden)

Yusuke Echigoya

Full Text Available Duchenne muscular dystrophy (DMD, one of the most common and lethal genetic disorders, and the mdx mouse myopathies are caused by a lack of dystrophin protein. These dystrophic muscles contain sporadic clusters of dystrophin-expressing revertant fibers (RFs, as detected by immunohistochemistry. RFs are known to arise from muscle precursor cells with spontaneous exon skipping (alternative splicing and clonally expand in size with increasing age through the process of muscle degeneration/regeneration. The expansion of revertant clusters is thought to represent the cumulative history of muscle regeneration and proliferation of such precursor cells. However, the precise mechanisms by which RFs arise and expand are poorly understood. Here, to test the effects of mutation types and aging on RF expansion and muscle regeneration, we examined the number of RFs in mdx mice (containing a nonsense mutation in exon 23 and mdx52 mice (containing deletion mutation of exon 52 with the same C57BL/6 background at 2, 6, 12, and 18months of age. Mdx mice displayed a significantly higher number of RFs compared to mdx52 mice in all age groups, suggesting that revertant fiber expansion largely depends on the type of mutation and/or location in the gene. A significant increase in the expression and clustering levels of RFs was found beginning at 6months of age in mdx mice compared with mdx52 mice. In contrast to the significant expansion of RFs with increasing age, the number of centrally nucleated fibers and embryonic myosin heavy chain-positive fibers (indicative of cumulative and current muscle regeneration, respectively decreased with age in both mouse strains. These results suggest that mutation types and aging differently affect revertant fiber expansion in mdx and mdx52 mice.

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.

Continuous anaerobic digestion of swine manure: ADM1-based modelling and effect of addition of swine manure fibers pretreated with aqueous ammonia soaking

International Nuclear Information System (INIS)

Jurado, E.; Antonopoulou, G.; Lyberatos, G.; Gavala, H.N.; Skiadas, I.V.

2016-01-01

Highlights: • Aqueous ammonia soaking (AAS) effect on methane yield: verification in continuously fed digesters. • AAS resulted in 98% increase of the methane yield of swine manure fibers in continuously fed digesters. • ADM1 was successfully adapted to simulating anaerobic digestion of swine manure. • Modification of hydrolysis kinetics was necessary for an adequate simulation of the digestion of AAS-treated fibers. - Abstract: Anaerobic digestion of manure fibers presents challenges due to their low biodegradability. Aqueous ammonia soaking (AAS) has been tested as a simple method to disrupt the lignocellulose and increase the methane yield of manure fibers. In the present study, mesophilic anaerobic digestion of AAS pretreated manure fibers was performed in CSTR-type digesters, fed with swine manure and/or a mixture of swine manure and AAS pretreated manure fibers (at a total solids based ratio of 0.52 manure per 0.48 fibers). Two different simulations were performed. In the first place, the Anaerobic Digestion Model 1 (ADM1) was fitted to a manure-fed, CSTR-type digester and validated by simulating the performance of a second reactor digesting manure. It was shown that disintegration and hydrolysis of the solid matter of manure was such a slow process that the organic particulate matter did not significantly contribute to the methane production. In the second place, ADM1 was used to describe biogas production from the codigestion of manure and AAS pretreated manure fibers. The model predictions regarding biogas production and methane content were in good agreement with the experimental data. It was shown that, AAS treatment significantly increased the disintegration and hydrolysis rate of the carbohydrate compounds of the fibers. The effect of the addition of AAS treated fibers on the kinetics of the conversion of other key compounds such as volatile fatty acids was negligible.

Kinetics of the Reduction of Cadmium Sulfate by Thiourea Dioxide in an Aqueous Ammonia Solution upon the Metallization of Carbon Fiber

Science.gov (United States)

Polenov, Yu. V.; Egorova, E. V.; Shestakov, G. A.

2018-01-01

The kinetics of the decomposition of thiourea dioxide and the reduction of cadmium cations by thiourea dioxide in an aqueous ammonia solution are studied. The kinetic parameters of these reactions are calculated using experimental data, allowing us to adjust conditions for the synthesis of cadmium coatings on carbon fiber of grade UKN-M-12K. The presence of the metal crystalline phase on the fiber is confirmed by means of X-ray diffraction, and its amount is measured via atomic absorption spectroscopy.

Efficiency of deodorant materials for ammonia reduction in indoor air

DEFF Research Database (Denmark)

Bivolarova, Mariya Petrova; Mizutani, Chiyomi; Melikov, Arsen Krikor

2014-01-01

A comparative study about the removability of ammonia gas in the air by activated carbon fiber (ACF) felt chemically treated with acid and a cotton fabric processed with iron phthalocyanine with copper (Cu) was performed in small-scale experiments. The test rig consisted of a heated plate and its...... proved activated carbon fiber felt with acid to be highly efficient in removing ammonia gas. Air temperature did not have profound effect on ACF performance. However, efficiency of the carbon fiber felt decreased when relative humidity was raised from 20 to 80%....

Planar optical waveguide sensor of ammonia

Science.gov (United States)

Sarkisov, Sergey S.; Curley, Michael J.; Boykin, Courtney; Diggs, Darnell E.; Grote, James G.; Hopkins, Frank K.

2004-12-01

We describe a novel sensor of ammonia based on a planar optical waveguide made of a thin film of polymer polyimide doped with indicator dye bromocresol purple. The film of dye-doped polyimide demonstrated reversible increase of absorption with a peak near 600 nm in response to presence of ammonia in ambient air. Coupling of input and output optic fibers with the waveguide was done by means of coupling prisms or coupling grooves. The latter configuration has the advantage of low cost, less sensitivity to temperature variation, and the possibility of coupling from both sides of the waveguide. Special experimental setup was built to test the sensor. It included test gas chamber with sealed optic fiber feed-throughs, gas filling line, laser source, photodetector, and signal processing hardware and software. The sensor was capable of detecting 100 ppm of ammonia in air within 8 seconds. Further increase of sensitivity can be achieved by adding more dye dopant to the polymer, increase of the length of the waveguide, and suppression of noise. Overexposure of the sensor to more than 5000 ppm of ammonia led to the saturation of the polymer film and, as a result, significant decrease of sensitivity and increase of the response time. The sensor can be used as low cost component of a distributed optical network of chemical sensors for monitoring presence of hazardous industrial pollutants in air.

Continuous anaerobic digestion of swine manure: ADM1-based modelling and effect of addition of swine manure fibers pretreated with aqueous ammonia soaking

DEFF Research Database (Denmark)

Jurado, E.; Antonopoulou, G.; Lyberatos, G.

2016-01-01

pretreated manure fibers was performed in CSTR-type digesters, fed with swine manure and/or a mixtureof swine manure and AAS pretreated manure fibers (at a total solids based ratio of 0.52 manure per0.48 fibers). Two different simulations were performed. In the first place, the Anaerobic Digestion Model 1......Anaerobic digestion of manure fibers presents challenges due to their low biodegradability. Aqueous ammonia soaking (AAS) has been tested as a simple method to disrupt the lignocellulose and increase the methane yield of manure fibers. In the present study, mesophilic anaerobic digestion of AAS...... (ADM1) was fitted to a manure-fed, CSTR-type digester and validated by simulating the performance of a second reactor digesting manure. It was shown that disintegration and hydrolysis of the solid matter of manure was such a slow process that the organic particulate matter did not significantly...

Cell fiber-based three-dimensional culture system for highly efficient expansion of human induced pluripotent stem cells.

Science.gov (United States)

Ikeda, Kazuhiro; Nagata, Shogo; Okitsu, Teru; Takeuchi, Shoji

2017-06-06

Human pluripotent stem cells are a potentially powerful cellular resource for application in regenerative medicine. Because such applications require large numbers of human pluripotent stem cell-derived cells, a scalable culture system of human pluripotent stem cell needs to be developed. Several suspension culture systems for human pluripotent stem cell expansion exist; however, it is difficult to control the thickness of cell aggregations in these systems, leading to increased cell death likely caused by limited diffusion of gases and nutrients into the aggregations. Here, we describe a scalable culture system using the cell fiber technology for the expansion of human induced pluripotent stem (iPS) cells. The cells were encapsulated and cultured within the core region of core-shell hydrogel microfibers, resulting in the formation of rod-shaped or fiber-shaped cell aggregations with sustained thickness and high viability. By encapsulating the cells with type I collagen, we demonstrated a long-term culture of the cells by serial passaging at a high expansion rate (14-fold in four days) while retaining its pluripotency. Therefore, our culture system could be used for large-scale expansion of human pluripotent stem cells for use in regenerative medicine.

Long-term ammonia removal in a coconut fiber-packed biofilter: analysis of N fractionation and reactor performance under steady-state and transient conditions.

Science.gov (United States)

Baquerizo, Guillermo; Maestre, Juan P; Machado, Vinicius C; Gamisans, Xavier; Gabriel, David

2009-05-01

A comprehensive study of long-term ammonia removal in a biofilter packed with coconut fiber is presented under both steady-state and transient conditions. Low and high ammonia loads were applied to the reactor by varying the inlet ammonia concentration from 90 to 260 ppm(v) and gas contact times ranging from 20 to 36 s. Gas samples and leachate measurements were periodically analyzed and used for characterizing biofilter performance in terms of removal efficiency (RE) and elimination capacity (EC). Also, N fractions in the leachate were quantified to both identify the experimental rates of nitritation and nitratation and to determine the N leachate distribution. Results showed stratification in the biofilter activity and, thus, most of the NH(3) removal was performed in the lower part of the reactor. An average EC of 0.5 kg N-NH(3)m(-3)d(-1) was obtained for the whole reactor with a maximum local average EC of 1.7 kg N-NH(3)m(-3)d(-1). Leachate analyses showed that a ratio of 1:1 of ammonium and nitrate ions in the leachate was obtained throughout steady-state operation at low ammonia loads with similar values for nitritation and nitratation rates. Low nitratation rates during high ammonia load periods occurred because large amounts of ammonium and nitrite accumulated in the packed bed, thus causing inhibition episodes on nitrite-oxidizing bacteria due to free ammonia accumulation. Mass balances showed that 50% of the ammonia fed to the reactor was oxidized to either nitrite or nitrate and the rest was recovered as ammonium indicating that sorption processes play a fundamental role in the treatment of ammonia by biofiltration.

Development and evaluation of optical fiber NH3 sensors for application in air quality monitoring

Science.gov (United States)

Huang, Yu; Wieck, Lucas; Tao, Shiquan

2013-02-01

Ammonia is a major air pollutant emitted from agricultural practices. Sources of ammonia include manure from animal feeding operations and fertilizer from cropping systems. Sensor technologies with capability of continuous real time monitoring of ammonia concentration in air are needed to qualify ammonia emissions from agricultural activities and further evaluate human and animal health effects, study ammonia environmental chemistry, and provide baseline data for air quality standard. We have developed fiber optic ammonia sensors using different sensing reagents and different polymers for immobilizing sensing reagents. The reversible fiber optic sensors have detection limits down to low ppbv levels. The response time of these sensors ranges from seconds to tens minutes depending on transducer design. In this paper, we report our results in the development and evaluation of fiber optic sensor technologies for air quality monitoring. The effect of change of temperature, humidity and carbon dioxide concentration on fiber optic ammonia sensors has been investigated. Carbon dioxide in air was found not interfere the fiber optic sensors for monitoring NH3. However, the change of humidity can cause interferences to some fiber optic NH3 sensors depending on the sensor's transducer design. The sensitivity of fiber optic NH3 sensors was found depends on temperature. Methods and techniques for eliminating these interferences have been proposed.

An evaluation of dilute acid and ammonia fiber explosion pretreatment for cellulosic ethanol production.

Science.gov (United States)

Mathew, Anil Kuruvilla; Parameshwaran, Binod; Sukumaran, Rajeev Kumar; Pandey, Ashok

2016-01-01

The challenge associated with cellulosic ethanol production is maximizing sugar yield at low cost. Current research is being focused to develop a pretreatment method to overcome biomass recalcitrance in an efficient way. This review is focused on two major pretreatments: dilute acid (DA) and ammonia fiber explosion (AFEX) pretreatment of corn stover and how these pretreatment cause morphological and chemical changes to corn stover in order to overcome the biomass recalcitrance. This review highlights the key differences of these two pretreatments based on compositional analysis, cellulose and its crystallinity, morphological changes, structural changes to lignin, enzymatic reactivity and enzyme adsorption onto pretreated solids and finally cellulosic ethanol production from the hydrolysate of DA and AFEX treated corn stover. Each stage of the process, AFEX pretreated corn stover was superior to DA treated corn stover. Copyright © 2015 Elsevier Ltd. All rights reserved.

Nanocrystalline samarium oxide coated fiber optic gas sensor

International Nuclear Information System (INIS)

Renganathan, B.; Sastikumar, D.; Srinivasan, R.; Ganesan, A.R.

2014-01-01

Highlights: • This fiber optic gas sensor works at room temperature. • As-prepared and annealed Sm 2 O 3 nanoparticles are act as sensor materials. • Sm 2 O 3 clad modified fiber detect the ammonia, ethanol and methanol gases. • The response of evanescent wave loss has been studied for different concentrations. - Abstract: Nanocrystalline Sm 2 O 3 coated fiber optic sensor is proposed for detecting toxic gases such as ammonia, methanol and ethanol vapors. Sm 2 O 3 in the as prepared form as well as annealed form have been used as gas sensing materials, by making them as cladding of a PMMA fiber. The spectral characteristics of the Sm 2 O 3 gas sensor are presented for ammonia, methanol and ethanol gases with different concentrations ranging from 0 to 500 ppm. The sensor exhibits a linear variation in the output light intensity with the concentration. The enhanced gas sensitivity and selectivity of the sensor for ethanol is discussed briefly

Methods of ammonia removal in anaerobic digestion: a review.

Science.gov (United States)

Krakat, Niclas; Demirel, Burak; Anjum, Reshma; Dietz, Donna

2017-10-01

The anaerobic digestion of substrates with high ammonia content has always been a bottleneck in the methanisation process of biomasses. Since microbial communities in anaerobic digesters are sensitive to free ammonia at certain conditions, the digestion of nitrogen-rich substrates such as livestock wastes may result in inhibition/toxicity eventually leading to process failures, unless appropriate engineering precautions are taken. There are many different options reported in literature to remove ammonia from anaerobic digesters to achieve a safe and stable process so that along with high methane yields, a good quality of effluents can also be obtained. Conventional techniques to remove ammonia include physical/chemical methods, immobilization and adaptation of microorganisms, while novel methods include ultrasonication, microwave, hollow fiber membranes and microbial fuel cell applications. This paper discusses conventional and novel methods of ammonia removal from anaerobic digesters using nitrogen-rich substrates, with particular focus on recent literature available about this topic.

Ion exchange fiber prepared by radiation grafting, (2)

International Nuclear Information System (INIS)

Sekiguchi, Hideaki; Fujiwara, Kunio; Fujii, Toshiaki; Takai, Takeshi; Kobayashi, Atsushi

1991-01-01

Ion exchange fiber prepared by radiation grafting has the capabilities for wide application as high performance materials. Extensive studies were made to evaluate the ion exchange fiber prepared by radiation grafting for removing some toxic or malodorous gases, continuing from the previous work (presented in Ebara Engng. Review, No. 146), in which the ability of removing ammonia with cation exchange fiber was investigated. The results of this study can be summarized by the following conclusions: (1) Methods of evaluating the ability of removing ammonia, acetaldehyde, and some lower fatty acids in low concentration were established, (2) Besides being effective for the removal of acidic or basic gases, neutral gas such as acetaldehyde can also be removed by adding some functional compounds to the ion exchange fiber, and (3) Ion exchange fiber prepared by radiation grafting is effective as a deodorizing filter. (author)

Plasma expansion: fundamentals and applications

International Nuclear Information System (INIS)

Engeln, R; Mazouffre, S; Vankan, P; Bakker, I; Schram, D C

2002-01-01

The study of plasma expansion is interesting from a fundamental point of view as well as from a more applied point of view. We here give a short overview of the way properties like density, velocity and temperature behave in an expanding thermal plasma. Experimental data show that the basic phenomena of plasma expansion are to some extent similar to those of the expansion of a hot neutral gas. From the application point of view, we present first results on the use of an expanding thermal plasma in the plasma-activated catalysis of ammonia, from N 2 -H 2 mixtures

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.

Ammonia toroid aligned perpendicular to the HH 1 and HH 2 bipolar outflow

International Nuclear Information System (INIS)

Torrelles, J.M.; Canto, J.; Rodriguez, L.F.; Ho, P.T.P.; Moran, J.M.; Universidad Nacional Autonoma de Mexico, Mexico City)

1985-01-01

The ammonia emission from the region containing the Herbig-Haro objects 1 and 2, which mark the presence of a bipolar outflow, was mapped. The ammonia observations delineate an elongated structure aligned perpendicular to the bipolar outflow. This ammonia condensation is centered between HH 1 and HH 2 and coincides with the recently discovered central radio continuum source. This continuum source has no optical counterpart. The ammonia spectrum at the position of the continuum source shows a remarkable splitting. Based on the orientation of the bipolar outflow, which is known to be oriented nearly perpendicular to the line of sight, and on theoretical considerations, it is concluded that the ammonia source is part of a toroid, viewed edge-on, in slow expansion driven by the wind pressure of the central source. This toroid may be the focusing mechanism for the bipolar outflow. Searches for ammonia condensations in the vicinity of other HH objects may help localize the energy sources of these systems. 26 references

Thermal expansion model for multiphase electronic packaging materials

International Nuclear Information System (INIS)

Allred, B.E.; Warren, W.E.

1991-01-01

Control of thermal expansion is often necessary in the design and selection of electronic packages. In some instances, it is desirable to have a coefficient of thermal expansion intermediate between values readily attainable with single or two phase materials. The addition of a third phase in the form of fillers, whiskers, or fibers can be used to attain intermediate expansions. To help design the thermal expansion of multiphase materials for specific applications, a closed form model has been developed that accurately predicts the effective elastic properties of isotropic filled materials and transversely isotropic lamina. Properties of filled matrix materials are used as inputs to the lamina model to obtain the composite elastic properties as a function of the volume fraction of each phase. Hybrid composites with two or more fiber types are easily handled with this model. This paper reports that results for glass, quartz, and Kevlar fibers with beta-eucryptite filled polymer matrices show good agreement with experimental results for X, Y, and Z thermal expansion coefficients

Measurement of thermal expansion coefficient of graphene diaphragm using optical fiber Fabry–Perot interference

International Nuclear Information System (INIS)

Li, Cheng; Liu, Qianwen; Peng, Xiaobin; Fan, Shangchun

2016-01-01

Application of the Fabry–Perot (FP) interference method for determining the coefficient of thermal expansion (CTE) of a graphene diaphragm is investigated in this paper. A miniature extrinsic FP interferometric (EFPI) sensor was fabricated by using an approximate 8-layer graphene diaphragm. The extremely thin diaphragm was transferred onto the endface of a ferrule with an inner diameter of 125 μ m, and van der Waals interactions between the graphene diaphragm and its substrate created a low finesse FP interferometer with a cavity length of 36.13 μ m. Double reference FP cavities using two cleaved optical fibers as reflectors were also constructed to differentially cancel the thermal expansion effects of the trapped gas and adhesive material. A temperature test demonstrated an approximate cavity length change of 166.1 nm °C −1 caused by film thermal expansion in the range of 20–60 °C. Then along with the established thermal deformation model of the suspended circular diaphragm, the calculated CTE ranging from  −9.98  ×  10 −6 K −1 to  −2.09  ×  10 −6 K −1 conformed well to the previously measured results. The proposed method would be applicable in other types of elastic materials as the sensitive diaphragm of an EFPI sensor over a wide temperature range. (paper)

Thermal Expansion Behavior of Hot-Pressed Engineered Matrices

Science.gov (United States)

Raj, S. V.

2016-01-01

Advanced engineered matrix composites (EMCs) require that the coefficient of thermal expansion (CTE) of the engineered matrix (EM) matches those of the fiber reinforcements as closely as possible in order to reduce thermal compatibility strains during heating and cooling of the composites. The present paper proposes a general concept for designing suitable matrices for long fiber reinforced composites using a rule of mixtures (ROM) approach to minimize the global differences in the thermal expansion mismatches between the fibers and the engineered matrix. Proof-of-concept studies were conducted to demonstrate the validity of the concept.

Effect of irradiation on thermal expansion of SiCf/SiC composites

International Nuclear Information System (INIS)

Senor, D.J.; Trimble, D.J.; Woods, J.J.

1996-06-01

Linear thermal expansion was measured on five different SiC-fiber-reinforced/SiC-matrix (SiC f /SiC) composite types in the unirradiated and irradiated conditions. Two matrices were studied in combination with Nicalon CG reinforcement and a 150 nm PyC fiber/matrix interface: chemical vapor infiltrated (CVI) SiC and liquid-phase polymer impregnated precursor (PIP) SiC. Composites of PIP SiC with Tyranno and HPZ fiber reinforcement and a 150 nm PyC interface were also tested, as were PIP SiC composites with Nicalon CG reinforcement and a 150 nm BN fiber/matrix interface. The irradiation was conducted in the Experimental Breeder Reactor-II at a nominal temperature of 1,000 C to doses of either 33 or 43 dpa-SiC. Irradiation caused complete fiber/matrix debonding in the CVI SiC composites due to a dimensional stability mismatch between fiber and matrix, while the PIP SiC composites partially retained their fiber/matrix interface after irradiation. However, the thermal expansion of all the materials tested was found to be primarily dependent on the matrix and independent of either the fiber or the fiber/matrix interface. Further, irradiation had no significant effect on thermal expansion for either the CVI SiC or PIP SiC composites. In general, the thermal expansion of the CVI SiC composites exceeded that of the PIP SiC composites, particularly at elevated temperatures, but the expansion of both matrix types was less than chemical vapor deposited (CVD) β-SiC at all temperatures

COMPACT ATHERMAL OPTICAL WAVEGUIDE USING THERMAL EXPANSION AMPLIFICATION

DEFF Research Database (Denmark)

2001-01-01

A method of temperature stabilising optical waveguides having positive thermal optical path length expansion, in particular fiber Bragg gratings or optical fiber DFB lasers or optical fiber DBR lasers, comprising affixing the optical waveguide to at least two points of a negative expanding fixture...

Fiber-Based Adsorbents Tailored for PLSS Ammonia and Formaldehyde Removal, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — Development of advanced lightweight Trace Contaminant Control (TCC) filters plays an important role in removing ammonia and formaldehyde contaminants?both those...

A Portable Array-Type Optical Fiber Sensing Instrument for Real-Time Gas Detection

Directory of Open Access Journals (Sweden)

San-Shan Hung

2016-12-01

Full Text Available A novel optical fiber array-type of sensing instrument with temperature compensation for real-time detection was developed to measure oxygen, carbon dioxide, and ammonia simultaneously. The proposed instrument is multi-sensing array integrated with real-time measurement module for portable applications. The sensing optical fibers were etched and polished before coating to increase sensitivities. The ammonia and temperature sensors were each composed of a dye-coated single-mode fiber with constructing a fiber Bragg grating and a long-period filter grating for detecting light intensity. Both carbon dioxide and oxygen sensing structures use multimode fibers where 1-hydroxy-3,6,8-pyrene trisulfonic acid trisodium salt is coated for carbon dioxide sensing and Tris(2,2′-bipyridyl dichlororuthenium(II hexahydrate and Tris(bipyridineruthenium(II chloride are coated for oxygen sensing. Gas-induced fluorescent light intensity variation was applied to detect gas concentration. The portable gas sensing array was set up by integrating with photo-electronic measurement modules and a human-machine interface to detect gases in real time. The measured data have been processed using piecewise-linear method. The sensitivity of the oxygen sensor were 1.54%/V and 9.62%/V for concentrations less than 1.5% and for concentrations between 1.5% and 6%, respectively. The sensitivity of the carbon dioxide sensor were 8.33%/V and 9.62%/V for concentrations less than 2% and for concentrations between 2% and 5%, respectively. For the ammonia sensor, the sensitivity was 27.78%/V, while ammonia concentration was less than 2%.

A Portable Array-Type Optical Fiber Sensing Instrument for Real-Time Gas Detection.

Science.gov (United States)

Hung, San-Shan; Chang, Hsing-Cheng; Chang, I-Nan

2016-12-08

A novel optical fiber array-type of sensing instrument with temperature compensation for real-time detection was developed to measure oxygen, carbon dioxide, and ammonia simultaneously. The proposed instrument is multi-sensing array integrated with real-time measurement module for portable applications. The sensing optical fibers were etched and polished before coating to increase sensitivities. The ammonia and temperature sensors were each composed of a dye-coated single-mode fiber with constructing a fiber Bragg grating and a long-period filter grating for detecting light intensity. Both carbon dioxide and oxygen sensing structures use multimode fibers where 1-hydroxy-3,6,8-pyrene trisulfonic acid trisodium salt is coated for carbon dioxide sensing and Tris(2,2'-bipyridyl) dichlororuthenium(II) hexahydrate and Tris(bipyridine)ruthenium(II) chloride are coated for oxygen sensing. Gas-induced fluorescent light intensity variation was applied to detect gas concentration. The portable gas sensing array was set up by integrating with photo-electronic measurement modules and a human-machine interface to detect gases in real time. The measured data have been processed using piecewise-linear method. The sensitivity of the oxygen sensor were 1.54%/V and 9.62%/V for concentrations less than 1.5% and for concentrations between 1.5% and 6%, respectively. The sensitivity of the carbon dioxide sensor were 8.33%/V and 9.62%/V for concentrations less than 2% and for concentrations between 2% and 5%, respectively. For the ammonia sensor, the sensitivity was 27.78%/V, while ammonia concentration was less than 2%.

Ammonia lowering reverses sarcopenia of cirrhosis by restoring skeletal muscle proteostasis.

Science.gov (United States)

Kumar, Avinash; Davuluri, Gangarao; Silva, Rafaella Nascimento E; Engelen, Marielle P K J; Ten Have, Gabrie A M; Prayson, Richard; Deutz, Nicolaas E P; Dasarathy, Srinivasan

2017-06-01

Sarcopenia or skeletal muscle loss is a frequent, potentially reversible complication in cirrhosis that adversely affects clinical outcomes. Hyperammonemia is a consistent abnormality in cirrhosis that results in impaired skeletal muscle protein synthesis and breakdown (proteostasis). Despite the availability of effective ammonia-lowering therapies, whether lowering ammonia restores proteostasis and increases muscle mass is unknown. Myotube diameter, protein synthesis, and molecular responses in C2C12 murine myotubes to withdrawal of ammonium acetate following 24-hour exposure to 10 mM ammonium acetate were complemented by in vivo studies in the hyperammonemic portacaval anastomosis rat and sham-operated, pair-fed Sprague-Dawley rats treated with ammonia-lowering therapy by l-ornithine l-aspartate and rifaximin orally for 4 weeks. We observed reduced myotube diameter, impaired protein synthesis, and increased autophagy flux in response to hyperammonemia, which were partially reversed following 24-hour and 48-hour withdrawal of ammonium acetate. Consistently, 4 weeks of ammonia-lowering therapy resulted in significant lowering of blood and skeletal muscle ammonia, increase in lean body mass, improved grip strength, higher skeletal muscle mass and diameter, and an increase in type 2 fibers in treated compared to untreated portacaval anastomosis rats. The increased skeletal muscle myostatin expression, reduced mammalian target of rapamycin complex 1 function, and hyperammonemic stress response including autophagy markers normally found in portacaval anastomosis rats were reversed by treatment with ammonia-lowering therapy. Despite significant improvement, molecular and functional readouts were not completely reversed by ammonia-lowering measures. Ammonia-lowering therapy results in improvement in skeletal muscle phenotype and function and molecular perturbations of hyperammonemia; these preclinical studies complement previous studies on ammonia-induced skeletal muscle

Emergency membrane contactor based absorption system for ammonia leaks in water treatment plants.

Science.gov (United States)

Shao, Jiahui; Fang, Xuliang; He, Yiliang; Jin, Qiang

2008-01-01

Abstract Because of the suspected health risks of trihalomethanes (THMs), more and more water treatment plants have replaced traditional chlorine disinfection process with chloramines but often without the proper absorption system installed in the case of ammonia leaks in the storage room. A pilot plant membrane absorption system was developed and installed in a water treatment plant for this purpose. Experimentally determined contact angle, surface tension, and corrosion tests indicated that the sulfuric acid was the proper choice as the absorbent for leaking ammonia using polypropylene hollow fiber membrane contactor. Effects of several operating conditions on the mass transfer coefficient, ammonia absorption, and removal efficiency were examined, including the liquid concentration, liquid velocity, and feed gas concentration. Under the operation conditions investigated, the gas absorption efficiency over 99.9% was achieved. This indicated that the designed pilot plant membrane absorption system was effective to absorb the leaking ammonia in the model storage room. The removal rate of the ammonia in the model storage room was also experimentally and theoretically found to be primarily determined by the ammonia suction flow rate from the ammonia storage room to the membrane contactor. The ammonia removal rate of 99.9% was expected to be achieved within 1.3 h at the ammonia gas flow rate of 500 m3/h. The success of the pilot plant membrane absorption system developed in this study illustrated the potential of this technology for ammonia leaks in water treatment plant, also paved the way towards a larger scale application.

Cryogenic fiber optic temperature sensor and method of manufacturing the same

Science.gov (United States)

Kochergin, Vladimir (Inventor)

2012-01-01

This invention teaches the fiber optic sensors temperature sensors for cryogenic temperature range with improved sensitivity and resolution, and method of making said sensors. In more detail, the present invention is related to enhancement of temperature sensitivity of fiber optic temperature sensors at cryogenic temperatures by utilizing nanomaterials with a thermal expansion coefficient that is smaller than the thermal expansion coefficient of the optical fiber but larger in absolute value than the thermal expansion coefficient of the optical fiber at least over a range of temperatures.

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 ...

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.)

Chitosan fibers with improved biological and mechanical properties for tissue engineering applications.

Science.gov (United States)

Albanna, Mohammad Z; Bou-Akl, Therese H; Blowytsky, Oksana; Walters, Henry L; Matthew, Howard W T

2013-04-01

The low mechanical properties of hydrogel materials such as chitosan hinder their broad utility for tissue engineering applications. Previous research efforts improved the mechanical properties of chitosan fiber through chemical and physical modifications; however, unfavorable toxicity effects on cells were reported. In this paper, we report the preparation of chitosan fibers with improved mechanical and biocompatibility properties. The structure-property relationships of extruded chitosan fibers were explored by varying acetic acid (AA) concentration, ammonia concentration, annealing temperature and degree of heparin crosslinking. Results showed that optimizing AA concentration to 2vol% improved fiber strength and stiffness by 2-fold. Extruding chitosan solution into 25wt% of ammonia solution reduced fiber diameters and improved fiber strength by 2-fold and stiffness by 3-fold, due to an increase in crystallinity as confirmed by XRD. Fiber annealing further reduced fiber diameter and improved fiber strength and stiffness as temperature increased. Chitosan fibers crosslinked with heparin had increased diameter but lower strength and stiffness properties and higher breaking strain values. When individual parameters were combined, further improvement in fiber mechanical properties was achieved. All mechanically improved fibers and heparin crosslinked fibers promoted valvular interstitial cells (VIC) attachment and growth over 10 day cultures. Our results demonstrate the ability to substantially improve the mechanical properties of chitosan fibers without adversely affecting their biological properties. The investigated treatments offer numerous advantages over previous physical/chemical modifications and thus are expected to expand the utility of chitosan fibers with tunable mechanical properties in various tissue engineering applications. Copyright © 2012 Elsevier Ltd. All rights reserved.

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.

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.

Comparative study of irreversibilities in an aqua-ammonia absorption refrigeration system

Energy Technology Data Exchange (ETDEWEB)

Ataer, O E [Gazi Univ., Ankara (TR). Mechanical Engineering Dept.; Gogus, Y [Middle East Technical Univ., Ankara (Turkey)

1991-03-01

Irreversibilities in components of an aqua-ammonia absorption refrigeration system (ARS) have been determined by second law analysis. The components of the ARS are as follows: condenser, evaporator, absorber, generator, pump, expansion valves, mixture heat exchanger and refrigerant heat exchanger. It is assumed that the ammonia concentration at the generator exit is, independent of the other parameters, equal to 0.999 and at the evaporator exit the gas is saturated vapour. Pressure losses between the generator and condenser, and the evaporator and absorber are taken into consideration. In the results the dimensionless exergy loss of each component, the exergetic coefficient of performance, the coefficient of performance and the circulation ratio are given graphically for each different generator, evaporator, condenser and absorber temperature. (author).

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

A volatile-solvent gas fiber sensor based on polyaniline film coated on superstructure fiber Bragg gratings

International Nuclear Information System (INIS)

Ai, L; Chen, T C; Su, W K; Mau, J C; Liu, W F

2008-01-01

A fiber sensor based on a polyaniline (PANI) film that is coated on the surface of an etched superstructure fiber grating to detect volatile solvent vapors is experimentally demonstrated. This sensing mechanism is based on the interaction of the testing gas with the polyaniline coating film, which changes the film index, resulting in a shift in the Bragg wavelength. The sensitivity of this sensor to ammonia (NH 3 ) gas is about 0.073 pm ppm −1 , which depends on the optical characteristics of the fiber grating, the diameter of the fiber cladding and the constituents of the sensing film. Methanol concentrations can also be measured using this sensing scheme. The sensitivity of this sensor must be improved to provide a simple, reliable, repeatable and non-destructive method for sensing various chemical gases. (technical design note)

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

Optimization of Pt-Ir on carbon fiber paper for the electro-oxidation of ammonia in alkaline media

International Nuclear Information System (INIS)

Boggs, Bryan K.; Botte, Gerardine G.

2010-01-01

Plating bath concentrations of Pt(IV) and Ir(III) have been optimized as well as the total catalytic loading of bimetallic Pt-Ir alloy for the electro-oxidation of ammonia in alkaline media at standard conditions. This was accomplished using cyclic voltammetry, scanning electron microscopy (SEM), energy dispersive X-ray (EDX), and statistical optimization tools. Concentrations of Pt(IV) and Ir(III) of the plating bath strongly influence electrode surface atomic compositions of the Pt-Ir alloy directly affecting the electro-oxidation behavior of ammonia. Several anode materials were studied using cyclic voltammetry, which demonstrated that Pt-Ir was the most active catalyst for the electro-oxidation of ammonia. Criteria for optimization were minimizing the climatic oxidation overpotential for ammonia and maximizing the exchange current density. Optimized bath composition was found to be 8.844 ± 0.001 g L -1 Pt(IV) and 4.112 ± 0.001 g L -1 Ir(III) based on electrochemical techniques. Physical characterization of the electrodes by SEM indicates that the plating bath concentrations of Pt and Ir influence the growth and deposition behavior of the alloy.

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

Reversible intercalation of ammonia molecules into a layered double hydroxide structure without exchanging nitrate counter-ions

International Nuclear Information System (INIS)

Carbajal Arizaga, Gregorio Guadalupe; Wypych, Fernando; Castillon Barraza, Felipe; Contreras Lopez, Oscar Edel

2010-01-01

A zinc/aluminum LDH was precipitated with recycled ammonia from a chemical vapor deposition reaction. The LDH presented a crystalline phase with basal distance of 8.9 A, typical for nitrate-containing LDHs, and another phase with a basal distance of 13.9 A. Thermal treatment at 150 o C eliminated the phase with the bigger basal distance leaving only the anhydrous nitrate-intercalated LDH structure with 8.9 A. Intense N-H stretching modes in the FTIR spectra suggested that the expansion was due to intercalation of ammonia in the form of [NH 4 (NH 3 ) n ] + species. When additional samples were precipitated with pure ammonia, the conventional LDH nitrate structure was obtained (8.9 A basal distance) at pH=7, as well as a pure crystalline phase with 13.9 A basal distance at pH=10 due to ammonia intercalation that can be removed by heating at 150 o C or by stirring in acetone, confirming a unusual sensu stricto intercalation process into a LDH without exchanging nitrate ions. - Graphical abstract: LDH-nitrate precipitated with ammonia expands the interlayer space if ammonia is bubbled up to pH 10. The basal distance decreased when the compound was heated at 150 o C or stirred in acetone. Nitrate ions are not exchanged.

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

A treatment of expansive soil using different additives

Directory of Open Access Journals (Sweden)

Bestun J. Nareeman

2010-11-01

Full Text Available There are many factors that govern the expansion behavior of soil. The primary factors are a change in water contentand the amount and type of clay size particles in the soil. Other important factors affecting the expansion behavior include the typeof soil (natural or fill, condition of the soil in terms of dry density and moisture content, magnitude of the surcharge pressure,and amount of no expansive material such as gravel or cobble size particles.In this paper, a swelling soil from the site Hamamuk earth dam, which is located in Koya town north of Iraq, is treated by fourtypes of additives; cement, steel fibers, gasoline fuel and injection by cement grout.The treatment of the expansive soil with 5 % of cement or steel fibers or the injection with cement grout revealed a betterimprovement while 4 % of gasoline oil is sufficient to reveal the optimum treatment by this material. The angle of internal friction is notaffected by the treatment while the cohesion between particles is slightly affected by these additives due to a change in the adhesionbetween the additive and soil particles.

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

Identification of Important Process Variables for Fiber Spinning of Protein Nanotubes Generated from Waste Materials

Science.gov (United States)

2012-01-11

PEEK Polyether ether ketone POM Polarized optical microscopy PT Phosphate-Tris (spinning buffer) SDS-PAGE Sodium dodecyl sulfate...the form of a gas such as water, ammonia, carbon monoxide, hydrogen cyanide , carbon dioxide and nitrogen. Carbonization is carried out at... steel . Therefore, spider silk fibers possess the desirable mechanical properties for lightweight, high-performance fiber, and composite applications

Liberation of ammonia by cyanobacteria

Energy Technology Data Exchange (ETDEWEB)

Newton, J.W.

1986-04-01

Photoheterotrophic nitrogen-fixing cyanobacteria release ammonia when treated with methionine sulfoximine (MSX) to inhibit nitrogen incorporation into protein. This released ammonia can be derived from recently fixed nitrogen (nitrogen atmosphere) or endogenous reserves (argon atmosphere). Anaerobic ammonia release requires light and is stimulated by the photosystem II herbicides DCMU and Atrazine, regardless of the source of ammonia. As much as one quarter of the total cellular nitrogen can be released as ammonia by cyanbacteria treated with MSX and DCMU under argon in light. Chromatography of cell extracts indicates that virtually all cellular proteins are degraded. DCMU and Atrazine, at very low concentration, inhibit sustained uptake of the ammonia analog /sup 14/C methylamine. These data indicate that the herbicides interrupt ammonia uptake and retention by the cells, and support a role for photosystem II in ammonia metabolism.

Liberation of ammonia by cyanobacteria

International Nuclear Information System (INIS)

Newton, J.W.

1986-01-01

Photoheterotrophic nitrogen-fixing cyanobacteria release ammonia when treated with methionine sulfoximine (MSX) to inhibit nitrogen incorporation into protein. This released ammonia can be derived from recently fixed nitrogen (nitrogen atmosphere) or endogenous reserves (argon atmosphere). Anaerobic ammonia release requires light and is stimulated by the photosystem II herbicides DCMU and Atrazine, regardless of the source of ammonia. As much as one quarter of the total cellular nitrogen can be released as ammonia by cyanbacteria treated with MSX and DCMU under argon in light. Chromatography of cell extracts indicates that virtually all cellular proteins are degraded. DCMU and Atrazine, at very low concentration, inhibit sustained uptake of the ammonia analog 14 C methylamine. These data indicate that the herbicides interrupt ammonia uptake and retention by the cells, and support a role for photosystem II in ammonia metabolism

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

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.

Interactions between ammonia and nitrite oxidizing bacteria in co-cultures: Is there evidence for mutualism, commensalism, or competition?

Energy Technology Data Exchange (ETDEWEB)

Sayavedra-Soto, Luis [Oregon State Univ., Corvallis, OR (United States); Arp, Daniel [Oregon State Univ., Corvallis, OR (United States)

2017-08-01

Nitrification is a two-step environmental microbial process in the nitrogen cycle in which ammonia is oxidized to nitrate. Ammonia-oxidizing bacteria and archaea oxidize ammonia to nitrite and nitrite is oxidized to nitrate by nitrite-oxidizing bacteria. These microorganisms, which likely act in concert in a microbial community, play critical roles in the movement of inorganic N in soils, sediments and waters and are essential to the balance of the nitrogen cycle. Anthropogenic activity has altered the balance of the nitrogen cycle through agriculture practices and organic waste byproducts. Through their influence on available N for plant growth, nitrifying microorganisms influence plant productivity for food and fiber production and the associated carbon sequestration. N Fertilizer production, primarily as ammonia, requires large inputs of natural gas and hydrogen. In croplands fertilized with ammonia-based fertilizers, nitrifiers contribute to the mobilization of this N by producing nitrate (NO3-), wasting the energy used in the production and application of ammonia-based fertilizer. The resulting nitrate is readily leached from these soils, oxidized to gaseous N oxides (greenhouse gases), and denitrified to N2 (which is no longer available as a plant N source). Still, ammonia oxidizers are beneficial in the treatment of wastewater and they also show potential to contribute to microbial bioremediation strategies for clean up of environments contaminated with chlorinated hydrocarbons. Mitigation of the negative effects and exploitation of the beneficial effects of nitrifiers will be facilitated by a systems-level understanding of the interactions of ammonia-oxidizing bacteria and nitrite-oxidizing bacteria with the environment and with each other.

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.

Fiber optic muzzle brake tip for reducing fiber burnback and stone retropulsion during thulium fiber laser lithotripsy

Science.gov (United States)

Hutchens, Thomas C.; Gonzalez, David A.; Irby, Pierce B.; Fried, Nathaniel M.

2017-01-01

The experimental thulium fiber laser (TFL) is being explored as an alternative to the current clinical gold standard Holmium:YAG laser for lithotripsy. The near single-mode TFL beam allows coupling of higher power into smaller optical fibers than the multimode Holmium laser beam profile, without proximal fiber tip degradation. A smaller fiber is desirable because it provides more space in the ureteroscope working channel for increased saline irrigation rates and allows maximum ureteroscope deflection. However, distal fiber tip burnback increases as fiber diameter decreases. Previous studies utilizing hollow steel sheaths around recessed distal fiber tips reduced fiber burnback but increased stone retropulsion. A "fiber muzzle brake" was tested for reducing both fiber burnback and stone retropulsion by manipulating vapor bubble expansion. TFL lithotripsy studies were performed at 1908 nm, 35 mJ, 500 μs, and 300 Hz using a 100-μm-core fiber. The optimal stainless steel muzzle brake tip tested consisted of a 1-cm-long, 560-μm-outer-diameter, 360-μm-inner-diameter tube with a 275-μm-diameter through hole located 250 μm from the distal end. The fiber tip was recessed a distance of 500 μm. Stone phantom retropulsion, fiber tip burnback, and calcium oxalate stone ablation studies were performed ex vivo. Small stones with a mass of 40±4 mg and 4-mm-diameter were ablated over a 1.5-mm sieve in 25±4 s (n=10) without visible distal fiber tip burnback. Reduction in stone phantom retropulsion distance by 50% and 85% was observed when using muzzle brake tips versus 100-μm-core bare fibers and hollow steel tip fibers, respectively. The muzzle brake fiber tip simultaneously provided efficient stone ablation, reduced stone retropulsion, and minimal fiber degradation during TFL lithotripsy.

ZnO nanoparticles based fiber optic gas sensor

Energy Technology Data Exchange (ETDEWEB)

Narasimman, S.; Sivacoumar, R.; Alex, Z. C. [MEMS and Sensor Division, School of Electronics Engineering, VIT University, Vellore 632 014 (India); Balakrishnan, L., E-mail: bslv85@gmail.com; Meher, S. R. [Materials Physics Division, School of Advanced Sciences, VIT University, Vellore 632 014 (India)

2016-05-23

In this work, ZnO nanoparticles were synthesized by simple aqueous chemical route method. The synthesized ZnO nanoparticles were characterized by X-ray diffraction and scanning electron microscope. The sensitivity of the nanoparticles was studied for different gases like acetone, ammonia and ethanol in terms of variation in spectral light intensity. The XRD and SEM analysis confirms the formation of hexagonal wurtzite structure with the grain size of 11.2 nm. The small cladding region of the optical fiber was replaced with the synthesized nanoparticles. The light spectrum was recorded for different gas concentrations. The synthesized nanoparticles showed high sensitivity towards ammonia in low ppm level and acetone in high ppm level.

Sensing application of an optical fiber dip coated with L-Cystein ethyl ester hydrochloride capped ZnTe quantum dots

Directory of Open Access Journals (Sweden)

Sundaray Madhulita

2016-09-01

Full Text Available Optical fiber in conjunction with ZnTe quantum dots (QDs is investigated for sensing application. ZnTe QDs, are synthesized by a simple chemical bottom up approach. Quantum dots are capped with L-Cystein ethyl ester hydrochloride (LEEH, to increase their stability. Then LEEH capped ZnTe QDs, whose size is estimated as 2.29 nm by effective mass approximation (EMA, are dip-coated on a cladding removed optical fiber. Different concentrations of alcohol and ammonia are used to investigate the sensing behavior. It is found that sensitivity of the sensor increases with the use of QDs for both alcohol and ammonia.

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....

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.

Influence of Hybridizing Flax and Hemp-Agave Fibers with Glass Fiber as Reinforcement in a Polyurethane Composite

Directory of Open Access Journals (Sweden)

Pankaj Pandey

2016-05-01

Full Text Available In this study, six combinations of flax, hemp, and glass fiber were investigated for a hybrid reinforcement system in a polyurethane (PU composite. The natural fibers were combined with glass fibers in a PU composite in order to achieve a better mechanical reinforcement in the composite material. The effect of fiber hybridization in PU composites was evaluated through physical and mechanical properties such as water absorption (WA, specific gravity (SG, coefficient of linear thermal expansion (CLTE, flexural and compression properties, and hardness. The mechanical properties of hybridized samples showed mixed trends compared to the unhybridized samples, but hybridization with glass fiber reduced water absorption by 37% and 43% for flax and hemp-agave PU composites respectively.

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.

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

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...

Multiscale characterization of chemical–mechanical interactions between polymer fibers and cementitious matrix

Energy Technology Data Exchange (ETDEWEB)

Hernández-Cruz, Daniel; Hargis, Craig W.; Bae, Sungchul; Itty, Pierre A.; Meral, Cagla; Dominowski, Jolee; Radler, Michael J.; Kilcoyne, David A.; Monteiro, Paulo J. M.

2014-04-01

Together with a series of mechanical tests, the interactions and potential bonding between polymeric fibers and cementitious materials were studied using scanning transmission X-ray microscopy (STXM) and microtomography (lCT). Experimental results showed that these techniques have great potential to characterize the polymer fiber-hydrated cement-paste matrix interface, as well as differentiating the chemistry of the two components of a bi-polymer (hybrid) fiber the polypropylene core and the ethylene acrylic acid copolymer sheath. Similarly, chemical interactions between the hybrid fiber and the cement hydration products were observed, indicating the chemical bonding between the sheath and the hardened cement paste matrix. Microtomography allowed visualization of the performance of the samples, and the distribution and orientation of the two types of fiber in mortar. Beam flexure tests confirmed improved tensile strength of mixes containing hybrid fibers, and expansion bar tests showed similar reductions in expansion for the polypropylene and hybrid fiber mortar bars.

Optical fiber sensors for harsh environments

Science.gov (United States)

Xu, Juncheng; Wang, Anbo

2007-02-06

A diaphragm optic sensor comprises a ferrule including a bore having an optical fiber disposed therein and a diaphragm attached to the ferrule, the diaphragm being spaced apart from the ferrule to form a Fabry-Perot cavity. The cavity is formed by creating a pit in the ferrule or in the diaphragm. The components of the sensor are preferably welded together, preferably by laser welding. In some embodiments, the entire ferrule is bonded to the fiber along the entire length of the fiber within the ferrule; in other embodiments, only a portion of the ferrule is welded to the fiber. A partial vacuum is preferably formed in the pit. A small piece of optical fiber with a coefficient of thermal expansion chosen to compensate for mismatches between the main fiber and ferrule may be spliced to the end of the fiber.

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

Production of activated carbon by using pyrolysis process in an ammonia atmosphere

Science.gov (United States)

Indayaningsih, N.; Destyorini, F.; Purawiardi, R. I.; Insiyanda, D. R.; Widodo, H.

2017-04-01

Activated carbon is materials that have wide applications, including supercapacitor materials, absorbent in chemical industry, and absorbent material in the chemical industry. This study has carried out for the manufacturing of activated carbon from inexpensive materials through efficient processes. Carbon material was made from coconut fibers through pyrolysis process at temperature of 650, 700, 750 and 800°C. Aim of this study was to obtain carbon material that has a large surface area. Pyrolysis process is carried out in an inert atmosphere (N2 gas) at a temperature of 450°C for 30 minutes, followed by pyrolysis process in an ammonia atmosphere at 800°C for 2 hours. The pyrolysis results showed that the etching process in ammonia is occurred; as it obtained some greater surface area when compared with the pyrolisis process in an atmosphere by inert gas only. The resulted activated carbon also showed to have good properties in surface area and total pore volume.

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.

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.

Infrared observations of circumstellar ammonia in OH/IR supergiants

International Nuclear Information System (INIS)

McLaren, R.A.; Betz, A.L.

1980-01-01

Ammonia has been detected in the circumstellar envelopes of VY Canis Majoris, VX Sagittarii, and IRC+10420 by means of several absorption lines in the ν 2 vibration-rotation band near 950 cm -1 . The line profiles are well resolved (0.2 km s -1 resolution) and show the gas being accelerated to terminal expansion velocities near 30 km s -1 . The observations reveal a method for determining the position of the central star on VLBI maps of OH maser emission to an accuracy of approx.0''.2. A firm lower limit of 2 x 10 15 cm -2 is obtained for the NH 3 column density in VY Canis Majoris

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.

Fiber optic assembly and method of making same

Energy Technology Data Exchange (ETDEWEB)

Kramer, D.P.; Beckman, T.M.

1995-12-31

There is provided an assembly having a light guiding medium sealed to a holder. Preferably the holder is a metal shell and a light guiding medium is an optical fiber of glass or sapphire whisker. The assembly includes a sealing medium which sealingly engages the metal holder to the fiber. In the formation of the assembly, the seal is essentially hermetic having a capability of minimizing leakage having a helium leak rate of less than 1 {times} 10{sup {minus}8} cubic centimeters per second and high strength having a capability of withstanding pressures of 100,000 psi or greater. The features of the assembly are obtained by a specific preparation method and by selection of specific starting materials. The fiber is selected to have a sufficiently high coefficient of thermal expansion which minimizes strains in the component during fabrication, as a result of fabrication, and during use. The other components are selected to be of a material having compatible coefficients of thermal expansion (TEC) where the TEC of the holder is greater than or equal to the TEC of the sealing material. The TEC of the sealing material is in turn greater than or equal to the TEC of the fiber. It is preferred that the materials be selected so that their respective coefficients of thermal expansion are close as possible to one another and they may all be equal.

Nanomechanics of electrospun phospholipid fiber

Energy Technology Data Exchange (ETDEWEB)

Mendes, Ana C., E-mail: anac@food.dtu.dk, E-mail: ioach@food.dtu.dk; Chronakis, Ioannis S., E-mail: anac@food.dtu.dk, E-mail: ioach@food.dtu.dk [Technical University of Denmark, DTU-Food, Søltofts Plads B227, DK-2800, Kgs. Lyngby (Denmark); Nikogeorgos, Nikolaos; Lee, Seunghwan [Department of Mechanical Engineering, Technical University of Denmark, DK-2800 Kgs. Lyngby (Denmark)

2015-06-01

Electrospun asolectin phospholipid fibers were prepared using isooctane as a solvent and had an average diameter of 6.1 ± 2.7 μm. Their mechanical properties were evaluated by nanoindentation using Atomic Force Microscopy, and their elastic modulus was found to be approximately 17.2 ± 1 MPa. At a cycle of piezo expansion-retraction (loading-unloading) of a silicon tip on a fiber, relatively high adhesion was observed during unloading. It is proposed that this was primarily due to molecular rearrangements at the utmost layers of the fiber caused by the indentation of the hydrophilic tip. The phospholipid fibers were shown to be stable in ambient conditions, preserving the modulus of elasticity up to 24 h.

Nanomechanics of electrospun phospholipid fiber

DEFF Research Database (Denmark)

Mendes, Ana Carina Loureiro; Nikogeorgos, Nikolaos; Lee, Seunghwan

2015-01-01

Electrospun asolectin phospholipid fibers were prepared using isooctane as a solvent and had an average diameter of 6.1 +/- 2.7 mu m. Their mechanical properties were evaluated by nanoindentation using Atomic Force Microscopy, and their elastic modulus was found to be approximately 17.2 +/- 1MPa....... At a cycle of piezo expansion-retraction (loading-unloading) of a silicon tip on a fiber, relatively high adhesion was observed during unloading. It is proposed that this was primarily due to molecular rearrangements at the utmost layers of the fiber caused by the indentation of the hydrophilic tip....... The phospholipid fibers were shown to be stable in ambient conditions, preserving the modulus of elasticity up to 24 h. (c) 2015 AIP Publishing LLC....

An FBG Optical Approach to Thermal Expansion Measurements under Hydrostatic Pressure.

Science.gov (United States)

Rosa, Priscila F S; Thomas, Sean M; Balakirev, Fedor F; Betts, Jon; Seo, Soonbeom; Bauer, Eric D; Thompson, Joe D; Jaime, Marcelo

2017-11-04

We report on an optical technique for measuring thermal expansion and magnetostriction at cryogenic temperatures and under applied hydrostatic pressures of 2.0 GPa. Optical fiber Bragg gratings inside a clamp-type pressure chamber are used to measure the strain in a millimeter-sized sample of CeRhIn₅. We describe the simultaneous measurement of two Bragg gratings in a single optical fiber using an optical sensing instrument capable of resolving changes in length [dL/L = (L- L₀)/L₀] on the order of 10 -7 . Our results demonstrate the possibility of performing high-resolution thermal expansion measurements under hydrostatic pressure, a capability previously hindered by the small working volumes typical of pressure cells.

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.

Expansion and functional properties of extruded snacks enriched with nutrition sources from food processing by-products.

Science.gov (United States)

Korkerd, Sopida; Wanlapa, Sorada; Puttanlek, Chureerat; Uttapap, Dudsadee; Rungsardthong, Vilai

2016-01-01

Rich sources of protein and dietary fiber from food processing by-products, defatted soybean meal, germinated brown rice meal, and mango peel fiber, were added to corn grit at 20 % (w/w) to produce fortified extruded snacks. Increase of total dietary fiber from 4.82 % (wb) to 5.92-17.80 % (wb) and protein from 5.03 % (wb) to 5.46-13.34 % were observed. The product indicated high expansion and good acceptance tested by sensory panels. There were 22.33-33.53 and 5.30-11.53 fold increase in the phenolics and antioxidant activity in the enriched snack products. The effects of feed moisture content, screw speed, and barrel temperature on expansion and nutritional properties of the extruded products were investigated by using response surface methodology. Regression equations describing the effect of each variable on the product responses were obtained. The snacks extruded with feed moisture 13-15 % (wb) and extrusion temperature at 160-180 °C indicated the products with high preference in terms of expansion ratio between insoluble dietary fiber and soluble dietary fiber balance. The results showed that the by-products could be successfully used for nutritional supplemented expanded snacks.

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.

Mechanical and physical properties of carbon-graphite fiber-reinforced polymers intended for implant suprastructures.

Science.gov (United States)

Segerström, Susanna; Ruyter, I Eystein

2007-09-01

Mechanical properties and quality of fiber/matrix adhesion of poly(methyl methacrylate) (PMMA)-based materials, reinforced with carbon-graphite (CG) fibers that are able to remain in a plastic state until polymerization, were examined. Tubes of cleaned braided CG fibers were treated with a sizing resin. Two resin mixtures, resin A and resin B, stable in the fluid state and containing different cross-linking agents, were reinforced with CG fiber loadings of 24, 36, and 47 wt% (20, 29, and 38 vol.%). In addition, resin B was reinforced with 58 wt% (47 vol.%). After heat-polymerization, flexural strength and modulus were evaluated, both dry and after water storage. Coefficient of thermal expansion, longitudinally and in the transverse direction of the specimens, was determined. Adhesion between fibers and matrix was evaluated with scanning electron microscopy (SEM). Flexural properties and linear coefficient of thermal expansion were similar for both fiber composites. With increased fiber loading, flexural properties increased. For 47 wt% fibers in polymer A the flexural strength was 547.7 (28.12) MPa and for polymer B 563.3 (89.24) MPa when water saturated. Linear coefficient of thermal expansion was for 47 wt% CG fiber-reinforced polymers; -2.5 x 10(-6) degrees C-1 longitudinally and 62.4 x 10(-6) degrees C-1 in the transverse direction of the specimens. SEM revealed good adhesion between fibers and matrix. More porosity was observed with fiber loading of 58 wt%. The fiber treatment and the developed resin matrices resulted in good adhesion between CG fibers and matrix. The properties observed indicate a potential for implant-retained prostheses.

A high selective methanol gas sensor based on molecular imprinted Ag-LaFeO3 fibers.

Science.gov (United States)

Rong, Qian; Zhang, Yumin; Wang, Chao; Zhu, Zhongqi; Zhang, Jin; Liu, Qingju

2017-09-21

Ag-LaFeO 3 molecularly imprinted polymers (ALMIPs) were fabricated, which provided special recognition sites to methanol. Then ALMIPs fiber 1, fiber 2 and fiber 3 were prepared using filter paper, silk and carbon fibers template, respectively. Based on the observation of X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), and Nitrogen adsorption surface area analyzer (BET), the structure, morphology and surface area of the fibers were characterized. The ALMIPs fibers (fiber 1, fiber 2 and fiber 3) show excellent selectivity and good response to methanol. The responses to 5 ppm methanol and the optimal operating temperature of ALMIPs fibers are 23.5 and 175 °C (fiber 1), 19.67 and 125 °C (fiber 2), 17.59 and 125 °C (fiber 3), and a lower response (≤10, 3, 2) to other test gases including formaldehyde, acetone, ethanol, ammonia, gasoline and benzene was measured, respectively.

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.

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...

New approach for high reliability, low loss splicing between silica and ZBLAN fibers

Science.gov (United States)

Carbonnier, Robin; Zheng, Wenxin

2018-02-01

In the past decade, ZBLAN (ZrF4-BaF2-LaF3-NaF) fibers have drawn increasing interest for laser operations at wavelengths where Fused Silica-based (SiO2) fibers do not perform well. One limitation to the expansion of ZBLAN fiber lasers today is the difficulty to efficiently inject and extract light in/from the guiding medium using SiO2 fibers. Although free space and butt coupling have provided acceptable results, consistent and long lasting physical joints between SiO2 and ZBLAN fibers will allow smaller, cheaper, and more robust component manufacturing. While low loss splices have been reported using a traditional splicing approach, the very low mechanical strength of the joint makes it difficult to scale. Difficulties in achieving a strong bond are mainly due to the large difference of transition temperature between ZBLAN and SiO2 fibers ( 260°C vs 1175°C). This paper presents results obtained by using the high thermal expansion coefficient of the ZBLAN fiber to encapsulate a smaller SiO2 fiber. A CO2 laser glass processing system was used to control the expansion and contraction of the ZBLAN material during the splicing process for optimum reliability. This method produced splices between 125μm ZBLAN to 80μm SiO2 fibers with average transmission loss of 0.225dB (measured at 1550nm) and average ultimate tension strength of 121.4gf. The Resulting splices can be durably packaged without excessive care. Other combinations using 125μm SiO2 fibers tapered to 80μm are also discussed.

Electron emission mechanism of carbon fiber cathode

International Nuclear Information System (INIS)

Liu Lie; Li Limin; Wen Jianchun; Wan Hong

2005-01-01

Models of electron emission mechanism are established concerning metal and carbon fiber cathodes. Correctness of the electron emission mechanism was proved according to micro-photos and electron scanning photos of cathodes respectively. The experimental results and analysis show that the surface flashover induces the electron emission of carbon fiber cathode and there are electron emission phenomena from the top of the carbon and also from its side surface. In addition, compared with the case of the stainless steel cathode, the plasma expansion velocity for the carbon fiber cathode is slower and the pulse duration of output microwave can be widened by using the carbon fiber cathode. (authors)

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.

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.

Application of the finite-element method and the eigenmode expansion method to investigate the periodic and spectral characteristic of discrete phase-shift fiber Bragg grating

Science.gov (United States)

He, Yue-Jing; Hung, Wei-Chih; Syu, Cheng-Jyun

2017-12-01

The finite-element method (FEM) and eigenmode expansion method (EEM) were adopted to analyze the guided modes and spectrum of phase-shift fiber Bragg grating at five phase-shift degrees (including zero, 1/4π, 1/2π, 3/4π, and π). In previous studies on optical fiber grating, conventional coupled-mode theory was crucial. This theory contains abstruse knowledge about physics and complex computational processes, and thus is challenging for users. Therefore, a numerical simulation method was coupled with a simple and rigorous design procedure to help beginners and users to overcome difficulty in entering the field; in addition, graphical simulation results were presented. To reduce the difference between the simulated context and the actual context, a perfectly matched layer and perfectly reflecting boundary were added to the FEM and the EEM. When the FEM was used for grid cutting, the object meshing method and the boundary meshing method proposed in this study were used to effectively enhance computational accuracy and substantially reduce the time required for simulation. In summary, users can use the simulation results in this study to easily and rapidly design an optical fiber communication system and optical sensors with spectral characteristics.

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

Infrared observations of circumstellar ammonia in OH/IR supergiants

Science.gov (United States)

Mclaren, R. A.; Betz, A. L.

1980-01-01

Ammonia has been detected in the circumstellar envelopes of VY Canis Majoris, VX Sagittarii, and IRC +10420 by means of several absorption lines in the nu-2 vibration-rotation band near 950 kaysers. The line profiles are well resolved (0.2 km/sec resolution) and show the gas being accelerated to terminal expansion velocities near 30 km/sec. The observations reveal a method for determining the position of the central star on VLBI maps of OH maser emission to an accuracy of approximately 0.2 arcsec. A firm lower limit of 2 x 10 to the 15th/sq cm is obtained for the NH3 column density in VY Canis Majoris.

Band gap of two-dimensional fiber-air photonic crystals

Energy Technology Data Exchange (ETDEWEB)

Yang, Shu, E-mail: yangshu5678@163.com; Li, Masha

2016-04-15

A two-dimensional photonic crystal (PC) composed of textile fiber and air is initially discussed in this paper. Textile materials are so called soft materials, which are different from the previous PCs composed of rigid materials. The plain wave expansion method is used to calculate band structure of different PCs by altering component properties or structural parameters. Results show that the dielectric constant of textile fibers, fiber filling ratio and lattice arrangement are effective factors which influence PCs' band gap. Yet lattice constant and fiber diameter make inconspicuous influence on the band gap feature.

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.

Critical review of pH sensing with optical fibers

Science.gov (United States)

Baldini, Francesco

1999-02-01

The chemical parameter most investigated with optical fibers is doubtless pH. The first pH optical fiber sensor was described in 1980. Since then, more than one hundred and twenty original papers describing different pH sensors have been published, based on absorption-based indicators on fluorophores. Such interest is perfectly justified, since pH detection is essential in many fields of application, ranging from the environment and medicine to industry and process control. Moreover, pH transduction can be used for measuring different chemical species, such as carbon dioxide, ammonia and pesticides. Notwithstanding the great number of prototypes realized in different laboratories all over the world, only a few products are available on the market. A critical analysis of the state of art in pH sensing using optical fibers is described, outlining the advantages and disadvantages of an optical approach.

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 ...

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.

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.

Effects of fiber ellipticity and orientation on dynamic stress concentrations in porous fiber-reinforced composites

Science.gov (United States)

Hasheminejad, Seyyed M.; Sanaei, Roozbeh

2007-11-01

Interaction of time harmonic fast longitudinal and shear incident plane waves with an elliptical fiber embedded in a porous elastic matrix is studied. The novel features of Biot dynamic theory of poroelasticity along with the classical method of eigen-function expansion and the pertinent boundary conditions are employed to develop a closed form series solution involving Mathieu and modified Mathieu functions of complex arguments. The complications arising due to the non-orthogonality of angular Mathieu functions corresponding to distinct wave numbers in addition to the problems associated with appearance of additional angular dependent terms in the boundary conditions are all avoided by expansion of the angular Mathieu functions in terms of transcendental functions and subsequent integration, leading to a linear set of independent equations in terms of the unknown scattering coefficients. A MATHEMATICA code is developed for computing the Mathieu functions in terms of complex Fourier coefficients which are themselves calculated by numerically solving appropriate sets of eigen-systems. The analytical results are illustrated with numerical examples in which an elastic fiber of elliptic cross section is insonified by a plane fast compressional or shear wave at normal incidence. The effects of fiber cross sectional ellipticity, angle of incidence (fiber two-dimensional orientation), and incident wave polarization (P, SV, SH) on dynamic stress concentrations are studied in a relatively wide frequency range. Limiting cases are considered and fair agreements with well-known solutions are established.

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

Nanomechanical Optical Fiber with Embedded Electrodes Actuated by Joule Heating.

Science.gov (United States)

Lian, Zhenggang; Segura, Martha; Podoliak, Nina; Feng, Xian; White, Nicholas; Horak, Peter

2014-07-31

Nanomechanical optical fibers with metal electrodes embedded in the jacket were fabricated by a multi-material co-draw technique. At the center of the fibers, two glass cores suspended by thin membranes and surrounded by air form a directional coupler that is highly temperature-dependent. We demonstrate optical switching between the two fiber cores by Joule heating of the electrodes with as little as 0.4 W electrical power, thereby demonstrating an electrically actuated all-fiber microelectromechanical system (MEMS). Simulations show that the main mechanism for optical switching is the transverse thermal expansion of the fiber structure.

Nanomechanical Optical Fiber with Embedded Electrodes Actuated by Joule Heating

Science.gov (United States)

Lian, Zhenggang; Segura, Martha; Podoliak, Nina; Feng, Xian; White, Nicholas; Horak, Peter

2014-01-01

Nanomechanical optical fibers with metal electrodes embedded in the jacket were fabricated by a multi-material co-draw technique. At the center of the fibers, two glass cores suspended by thin membranes and surrounded by air form a directional coupler that is highly temperature-dependent. We demonstrate optical switching between the two fiber cores by Joule heating of the electrodes with as little as 0.4 W electrical power, thereby demonstrating an electrically actuated all-fiber microelectromechanical system (MEMS). Simulations show that the main mechanism for optical switching is the transverse thermal expansion of the fiber structure. PMID:28788148

(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

A study on thermal residual stresses in the matrix and fiber of a misoriented short fiber composite

International Nuclear Information System (INIS)

Son, Bong Jin; Lee, Joon Hyun

1994-01-01

An elastic model is developed to predict the average thermal residual stresses in the matrix and fiber of a misoriented short fiber composite. The thermal residual stresses are induced by the mismatch in the coefficient of the thermal expansion of the matrix and fiber when the composite is subjected to a uniform temperature change. The model considers two special cases of fiber misorientation; two-dimensional in-plane and three-dimensional axisymmetric. The analytical formulation of the model is based on Eshelby's equivalent inclusion method and is unique in that it is able to account for interactions among fibers. The model is more general than past models and it is able to treat prior analyses of the simpler composite systems as extream cases. The present model is to investigate the effects of fiber volume fraction, distribution type, distribution cut-off angle, and aspect ratio on thermal residual stress for both in-plane and axisymmetric fiber misorientation. Fiber volume fraction, aspect ratio, and disturbution cut-off angle are shown to have more significant effects on the magnitude of the thermal residual stresses than fiber distrubution type for both in-plane and axisymmetric misorientation.

Controlling thermal deformation by using composite materials having variable fiber volume fraction

International Nuclear Information System (INIS)

Bouremana, M.; Tounsi, A.; Kaci, A.; Mechab, I.

2009-01-01

In application, many thin structural components such as beams, plates and shells experience a through-thickness temperature variation. This temperature variation can produce both an in-plane expansion and an out-of-plane (bending) curvature. Given that these thin components interact with or connect to other components, we often wish to minimize the thermal deformation or match the thermal deformation of another component. This is accomplished by using a composite whose fibers have a negative axial thermal expansion coefficient. By varying the fiber volume fraction within a symmetric laminated beam to create a functionally graded material (FGM), certain thermal deformations can be controlled or tailored. Specifically, a beam can be designed which does not curve under a steady-state through-thickness temperature variation. Continuous gradation of the fiber volume fraction in the FGM layer is modelled in the form of a mth power polynomial of the coordinate axis in thickness direction of the beam. The beam results are independent of the actual temperature values, within the limitations of steady-state heat transfer and constant material properties. The influence of volume fiber fraction distributions are studied to match or eliminate an in-plane expansion coefficient, or to match a desired axial stiffness. Combining two fiber types to create a hybrid FGM can offer desirable increase in axial and bending stiffness while still retaining the useful thermal deformation behavior.

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.

Thermal expansion and phase transformations of nitrogen-expanded austenite studied with in situ synchrotron X-ray diffraction

DEFF Research Database (Denmark)

Brink, Bastian; Ståhl, Kenny; Christiansen, Thomas Lundin

2014-01-01

Nitrogen-expanded austenite, _N, with high and low nitrogen contents was produced from AISI 316 grade stainless steel powder by gaseous nitriding in ammonia/hydrogen gas mixtures. In situ synchrotron X-ray diffraction was applied to investigate the thermal expansion and thermal stability...... as a fitting parameter. The stacking fault density is constant for temperatures up to 680 K, whereafter it decreases to nil. Surprisingly, a transition phase with composition M4N (M = Fe, Cr, Ni, Mo) appears for temperatures above 770 K. The linear coefficient of thermal expansion depends on the nitrogen...

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.

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.

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 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)

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.

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...

Preparation and properties of hexagonal boron nitride fibers used as high temperature membrane filter

Energy Technology Data Exchange (ETDEWEB)

Hou, Xinmei, E-mail: houxinmei@ustb.edu.cn; Yu, Ziyou; Li, Yang; Chou, Kuo-Chih

2014-01-01

Graphical abstract: - Highlights: • h-BN fibers were successfully fabricated using H{sub 3}BO{sub 3} and C{sub 3}H{sub 6}N{sub 6} as raw materials. • The obtained BN fibers were polycrystalline and uniform in morphology. • It exhibited good oxidation resistance and low thermal expansion coefficient. - Abstract: Hexagonal boron nitride fibers were synthesized via polymeric precursor method using boric acid (H{sub 3}BO{sub 3}) and melamine (C{sub 3}H{sub 6}N{sub 6}) as raw materials. The precursor fibers were synthesized by water bath and BN fibers were prepared from the precursor at 1873 K for 3 h in flowing nitrogen atmosphere. The crystalline phase and microstructures of BN fibers were examined by X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy and high resolution electron microscopy. The results showed that h-BN fibers with uniform morphology were successfully fabricated. The well-synthesized BN fibers were polycrystalline with 0.4–1.5 μm in diameter and 200–500 μm in length. The as-prepared samples exhibited good oxidation resistance and low thermal expansion coefficient at high temperature.

Fiber Bragg Grating sensors for structural health monitoring of Tsing Ma bridge: background and experimental observation

NARCIS (Netherlands)

Chan, T.H.T.; Yu, L.; Tam, H.Y.; Ni, Y.Q.; Liu, S.Y.; Chung, W.H.; Cheng, L.K.

2006-01-01

The rapid expansion of the optical fiber telecommunication industry due to the explosion of the Internet has substantially driven down the cost of optical components, making fiber optic sensors more economically viable. In addition, the rapid development of fiber-optic sensors, particularly the

Ammonia synthesis using magnetic induction method (MIM)

Science.gov (United States)

Puspitasari, P.; Razak, J. Abd; Yahya, N.

2012-09-01

The most challenging issues for ammonia synthesis is to get the high yield. New approach of ammonia synthesis by using Magnetic Induction Method (MIM) and the Helmholtz Coils has been proposed. The ammonia detection was done by using Kjeldahl Method and FTIR. The system was designed by using Autocad software. The magnetic field of MIM was vary from 100mT-200mT and the magnetic field for the Helmholtz coils was 14mT. The FTIR result shows that ammonia has been successfully formed at stretching peaks 1097,1119,1162,1236, 1377, and 1464 cm-1. UV-VIS result shows the ammonia bond at 195nm of wavelength. The ammonia yield was increase to 244.72μmole/g.h by using the MIM and six pairs of Helmholtz coils. Therefore this new method will be a new promising method to achieve the high yield ammonia at ambient condition (at 25δC and 1atm), under the Magnetic Induction Method (MIM).

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

Fiber Fabry-Perot interferometer with controllable temperature sensitivity.

Science.gov (United States)

Zhang, Xinpu; Peng, Wei; Zhang, Yang

2015-12-01

We proposed a fiber taper based on the Fabry-Perot (FP) interferometer structure with controllable temperature sensitivity. The FP interferometer is formed by inserting a segment of tapered fiber tip into the capillary and subsequently splicing the other end of the capillary to a single-mode fiber (SMF), the tapered fiber endface, and the spliced face form the FP cavity. Through controlling the inserted tapered fiber length, a series of FP interferometers were made. Because the inserted taper tip has the degree of freedom along the fiber axial, when the FP interferometer is subjected to temperature variation, the thermal expansion of the fiber taper tip will resist the FP cavity length change caused by the evolution of capillary length, and we can control the temperature sensitivity by adjusting the inserted taper length. In this structure, the equivalent thermal expansion coefficient of the FP interferometer can be defined; it was used to evaluate the temperature sensitivity of the FP interferometer, which provides an effective method to eliminate the temperature effect and to enhance other measurement accuracy. We fabricated the FP interferometers and calibrated their temperature characters by measuring the wavelength shift of the resonance dips in the reflection spectrum. In a temperature range of 50°C to 150°C, the corresponding temperature sensitivities can be controlled between 0 and 1.97 pm/°C when the inserted taper is between 75 and 160 μm. Because of its controllable temperature sensitivity, ease of fabrication, and low cost, this FP interferometer can meet different temperature sensitivity requirements in various application areas, especially in the fields which need temperature insensitivity.

Method for forming ammonia

Science.gov (United States)

Kong, Peter C.; Pink, Robert J.; Zuck, Larry D.

2008-08-19

A method for forming ammonia is disclosed and which includes the steps of forming a plasma; providing a source of metal particles, and supplying the metal particles to the plasma to form metal nitride particles; and providing a substance, and reacting the metal nitride particles with the substance to produce ammonia, and an oxide byproduct.

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.

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

Sensing characteristics of nanocrystalline bismuth oxide clad-modified fiber optic gas sensor

Science.gov (United States)

Manjula, M.; Karthikeyan, B.; Sastikumar, D.

2017-08-01

Gas sensing properties of nanocrystalline bismuth oxide clad - modified fiber optic sensor is reported for ammonia, ethanol, methanol and acetone gasses at room temperature. The output of sensor increases or decreases for certain gasses when the concentration of the gas is increased. The sensor exhibits high response and good selectivity to methanol gas. Time response characteristics of the sensor are also reported.

Plasma plume expansion dynamics in nanosecond Nd:YAG laserosteotome

Science.gov (United States)

Abbasi, Hamed; Rauter, Georg; Guzman, Raphael; Cattin, Philippe C.; Zam, Azhar

2018-02-01

In minimal invasive laser osteotomy precise information about the ablation process can be obtained with LIBS in order to avoid carbonization, or cutting of wrong types of tissue. Therefore, the collecting fiber for LIBS needs to be optimally placed in narrow cavities in the endoscope. To determine this optimal placement, the plasma plume expansion dynamics in ablation of bone tissue by the second harmonic of a nanosecond Nd:YAG laser at 532 nm has been studied. The laserinduced plasma plume was monitored in different time delays, from one nanosecond up to one hundred microseconds. Measurements were performed using high-speed gated illumination imaging. The expansion features were studied using illumination of the overall visible emission by using a gated intensified charged coupled device (ICCD). The camera was capable of having a minimum gate width (Optical FWHM) of 3 ns and the timing resolution (minimum temporal shift of the gate) of 10 ps. The imaging data were used to generate position-time data of the luminous plasma-front. Moreover, the velocity of the plasma plume expansion was studied based on the time-resolved intensity data. By knowing the plasma plume profile over time, the optimum position (axial distance from the laser spot) of the collecting fiber and optimal time delay (to have the best signal to noise ratio) in spatial-resolved and time-resolved laser-induced breakdown spectroscopy (LIBS) can be determined. Additionally, the function of plasma plume expansion could be used to study the shock wave of the plasma plume.

Enhanced electrochemical activity using vertically aligned carbon nanotube electrodes grown on carbon fiber

Directory of Open Access Journals (Sweden)

Evandro Augusto de Morais

2011-09-01

Full Text Available Vertically aligned carbon nanotubes were successfully grown on flexible carbon fibers by plasma enhanced chemical vapor deposition. The diameter of the CNT is controllable by adjusting the thickness of the catalyst Ni layer deposited on the fiber. Vertically aligned nanotubes were grown in a Plasma Enhanced Chemical Deposition system (PECVD at a temperature of 630 ºC, d.c. bias of -600 V and 160 and 68 sccm flow of ammonia and acetylene, respectively. Using cyclic voltammetry measurements, an increase of the surface area of our electrodes, up to 50 times higher, was observed in our samples with CNT. The combination of VACNTs with flexible carbon fibers can have a significant impact on applications ranging from sensors to electrodes for fuel cells.

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

Nutritive value of wheat straw treated with gaseous or liquid ammonia trough nylon bag and in vitro gas production techniques

Directory of Open Access Journals (Sweden)

Samad Sadeghi

2016-04-01

increased and their neutral detergent fiber (NDF and acid detergent fiber (ADF contents reduced significantly (P< 0.05 with increasing the level of ammonia in both gaseous or liquid forms, although, the 6% level was more affective. There were no significant differences between the experimental treatments in organic matter, ether extract and ash contents. Crude protein content increased from 3.71% in untreated wheat straw to 13.41% in treated straw with 6% ammonia in liquid form. The chemical composition measurements revealed that ammonia treatment in liquid form was more effective in comparison with the gaseous form. The increase in CP content of the treated wheat straw was in agreement with data reported by other workers. The lower levels of NDF and ADF of the straw due to ammonia treatments appear to be due to solubiliziation of hemicellulose component. The nylon bag measurements showed that soluble fraction (a and b, rate of degradation of fraction b (r, potential degradability (PD and effective degradability (ED were all associated with the level of applied ammonia. Dry matter disappearance significantly (P< 0.05 increased with increasing the level of ammonia mainly in gaseous form. For all the in situ parameters the most effective level of ammonia was 6%. Total produced gas after 24 hrs of incubation confirmed that the highest level of ammonia (6% had the greatest effects on a, c, ME, NEL, OMD and SCFA parameters. Conclusion The overall results showed that wheat straw treatment with 6% ammonia in either gaseous or liquid forms could improve its feeding value for ruminants significantly (P< 0.05. Straw treatment with ammonia in liquid form was totally more effective than the other form (gaseous. It seems that ammonia fixation in treated wheat straw with liquid ammonia has been related to the moisture content rather than its forms. In farm and commercial scales handling and application of large amount and liquid ammonia and treating straw is inapplicable. It was

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.

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.

Respiratory monitoring system based on fiber optic macro bending

Science.gov (United States)

Purnamaningsih, Retno Wigajatri; Widyakinanti, Astari; Dhia, Arika; Gumelar, Muhammad Raditya; Widianto, Arif; Randy, Muhammad; Soedibyo, Harry

2018-02-01

We proposed a respiratory monitoring system for living activities in human body based on fiber optic macro-bending for laboratory scale. The respiration sensor consists of a single-mode optical fiber and operating on a wavelength at around 1550 nm. The fiber optic was integrated into an elastic fabric placed on the chest and stomach of the monitored human subject. Deformations of the flexible textile involving deformations of the fiber optic bending curvature, which was proportional to the chest and stomach expansion. The deformation of the fiber was detected using photodetector and processed using microcontroller PIC18F14K50. The results showed that this system able to display various respiration pattern and rate for sleeping, and after walking and running activities in real time.

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.

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.

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...

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.

Research on corrosion detection for steel reinforced concrete structures using the fiber optical white light interferometer sensing technique

International Nuclear Information System (INIS)

Zhao, Xuefeng; Cui, Yanjun; Kong, Xianglong; Wei, Heming; Zhang, Pinglei; Sun, Changsen

2013-01-01

In this paper, a novel kind of steel rebar corrosion monitoring technique for steel reinforced concrete structures is proposed, designed, and tested. The technique is based on the fiber optical white light interferometer (WLI) sensing technique. Firstly, a feasibility test was carried out using an equal-strength beam for comparison of strain sensing ability between the WLI and a fiber Bragg grating (FBG). The comparison results showed that the sensitivity of the WLI is sufficient for corrosion expansion strain monitoring. Then, two WLI corrosion sensors (WLI-CSs) were designed, fabricated, and embedded into concrete specimens to monitor expansion strain caused by steel rebar corrosion. Their performance was studied in an accelerated electrochemical corrosion test. Experimental results show that expansion strain along the fiber optical coil winding area can be detected and measured accurately by the proposed sensor. The advantages of the proposed monitoring technique allow for quantitative corrosion expansion monitoring to be executed in real time for reinforced concrete structures and with low cost. (paper)

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.

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.

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.

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

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 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.

Compositional changes in swine manure fibers treated with aqueous ammonia soaking (AAS) resulting in increased methane potential

DEFF Research Database (Denmark)

Jurado, Esperanza; Hansen, Mads A.T.; Gavala, Hariklia N.

2013-01-01

and accessible during subsequent anaerobic digestion. This finding has confirmed earlier experimental results, showing that delignification was not necessarily the limiting factor during conversion of manure fibers into methane while cellulose accessibility during digestion seemed more crucial.......AAS treatment is a very efficient method to increase the methane potential of manure fibers. The chemical composition and supramolecular structures of swine manure fibers before and after AAS treatment was investigated in this study. Composition analyses, atomic force microscopy (AFM), scanning...

Biodegradable foams based on starch, polyvinyl alcohol, chitosan and sugarcane fibers obtained by extrusion

Directory of Open Access Journals (Sweden)

Flávia Debiagi

2011-10-01

Full Text Available Biodegradable foams made from cassava starch, polyvinyl alcohol (PVA, sugarcane bagasse fibers and chitosan were obtained by extrusion. The composites were prepared with formulations determined by a constrained ternary mixtures experimental design, using as variables: (X1 starch / PVA (100 - 70%, (X2 chitosan (0 - 2% and (X3 fibers from sugar cane (0 - 28%. The effects of varying proportions of these three components on foam properties were studied, as well the relationship between their properties and foam microstructure. The addition of starch/PVA in high proportions increased the expansion index and mechanical resistance of studied foams. Fibers addition improved the expansion and mechanical properties of the foams. There was a trend of red and yellow colors when the composites were produced with the highest proportions of fibers and chitosan, respectively. All the formulations were resistant to moisture content increase until 75% relative humidity of storage.

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...

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...

Squid pen-inspired chitinous functional materials: Hierarchical chitin fibers by centrifugal jet-spinning and transparent chitin fiber-reinforced composite

Science.gov (United States)

Jeong, Seung-Hwan; Kim, Joong-Kwon; Lim, Young-Woo; Hwang, Hyun-Bin; Kwon, Hee-Young; Bae, Byeong-Soo; Jin, Jungho

2018-01-01

Here, inspired by the fibrous composite structure of a squid pen, we introduce hierarchical chitin fibers (herein, termed "Chiber") and their transparent composites and demonstrate the potential of these chitinous functional materials as a sustainable separation-membrane and reinforcing filler for composites. We employ a centrifugal jet-spinning process to fabricate Chiber with aligned chitin nanofibrillar architectures, for which we discuss the processing-morphology relationship. A nonwoven fiber-mat made of Chiber exhibits excellent adsorbing performance for a toxic ionic dye (Congo Red), and has a low coefficient of thermal expansion comparable to that of glass fibers. Finally, we demonstrate a squid pen-mimetic transparent composite using Chiber and investigate its optical property.

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...

Improvement of anaerobic digestion performance by continuous nitrogen removal with a membrane contactor treating a substrate rich in ammonia and sulfide.

Science.gov (United States)

Lauterböck, B; Nikolausz, M; Lv, Z; Baumgartner, M; Liebhard, G; Fuchs, W

2014-04-01

The effect of reduced ammonia levels on anaerobic digestion was investigated. Two reactors were fed with slaughterhouse waste, one with a hollow fiber membrane contractor for ammonia removal and one without. Different organic loading rates (OLR) and free ammonia and sulfide concentrations were investigated. In the reactor with the membrane contactor, the NH4-N concentration was reduced threefold. At a moderate OLR (3.1 kg chemical oxygen demand - COD/m(3)/d), this reactor performed significantly better than the reference reactor. At high OLR (4.2 kg COD/m(3)/d), the reference reactor almost stopped producing methane (0.01 Nl/gCOD). The membrane reactor also showed a stable process with a methane yield of 0.23 Nl/g COD was achieved. Both reactors had predominantly a hydrogenotrophic microbial consortium, however in the membrane reactor the genus Methanosaeta (acetoclastic) was also detected. In general, all relevant parameters and the methanogenic consortium indicated improved anaerobic digestion of the reactor with the membrane. Copyright © 2014 Elsevier Ltd. All rights reserved.

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

Measurements of print-through in graphite fiber epoxy composites

Science.gov (United States)

Jaworske, Donald A.; Jeunnette, Timothy T.; Anzic, Judith M.

1989-01-01

High-reflectance accurate-contour mirrors are needed for solar dynamic space power systems. Graphite fiber epoxy composites are attractive candidates for such applications owing to their high modulus, near-zero coefficient of thermal expansion, and low mass. However, mirrors prepared from graphite fiber epoxy composite substrates often exhibit print-through, a distortion of the surface, which causes a loss in solar specular reflectance. Efforts to develop mirror substrates without print-through distortion require a means of quantifying print-through. Methods have been developed to quantify the degree of print-through in graphite fiber epoxy composite specimens using surface profilometry.

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

Maximum speed of dewetting on a fiber

NARCIS (Netherlands)

Chan, Tak Shing; Gueudre, Thomas; Snoeijer, Jacobus Hendrikus

2011-01-01

A solid object can be coated by a nonwetting liquid since a receding contact line cannot exceed a critical speed. We theoretically investigate this forced wetting transition for axisymmetric menisci on fibers of varying radii. First, we use a matched asymptotic expansion and derive the maximum speed

[Local application of bFGF and sucralfate during continuous tissue expansion].

Science.gov (United States)

Hu, Ya-lan; Guo, Shu-zhong; Lu, Kai-hua; Han, Yan; Lei, Yong-hong; Song, Bao-qiang; Pan, Yong

2003-01-01

To investigate the effect of local application of bFGF and sucralfate during continuous tissue expansion (CTE). CTE combined with local administration of bFGF and sucralfate was used in twelve patients with scar and nasal tip defects. Twenty three expanders were placed in the subcutaneous pockets through intralesion short incisions. Continuous expansion began at 1-3 days after expander implantation. The histomorphological changes and epidermal cell proliferation were observed. The clinical results were investigated. The average inflation time was 8.9 days. The average interval of the two operations was 13.5 days. The average hospitalization was 28.4 days. The average immediate stretch-back rate of the expanded skin was 25.7%. The clinical results were satisfactory without any complications. Histological examinations showed that the epidermal, granular and spinous layer became thicker. The basal cells increased significantly. The dermis thinned slightly and the collagen fibers became thicker. The elastic fiber regenerated significantly. Fibroblast and capillary density increased obviously. The immunohistochemistry analysis showed that the proliferation of epidemic basal cells was significant postoperatively. Local application of exogenous bFGF and sucralfate during CTE was feasible in patients. It could accelerate tissue expansion and improve the quality of expanded skin flap.

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.

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

Micromechanical Analysis of Crack Closure Mechanism for Intelligent Material Containing TiNi Fibers

Science.gov (United States)

Araki, Shigetoshi; Ono, Hiroyuki; Saito, Kenji

In our previous study, the micromechanical modeling of an intelligent material containing TiNi fibers was performed and the stress intensity factor KI at the tip of the crack in the material was expressed in terms of the magnitude of the shape memory shrinkage of the fibers and the thermal expansion strain in the material. In this study, the value of KI at the tip of the crack in the TiNi/epoxy material is calculated numerically by using analytical expressions obtained in our first report. As a result, we find that the KI value decreases with increasing shrink strain of the fibers, and this tendency agrees with that of the experimental result obtained by Shimamoto etal.(Trans. Jpn. Soc. Mech. Eng., Vol. 65, No. 634 (1999), pp. 1282-1286). Moreover, there exists an optimal value of the shrink strain of the fibers to make the KI value zero. The change in KI with temperature during the heating process from the reference temperature to the inverse austenitic finishing temperature of TiNi fiber is also consistent with the experimental result. These results can be explained by the changes in the shrink strain, the thermal expansion strain, and the elastic moduli of TiNi fiber with temperature. These results may be useful in designing intelligent materials containing TiNi fibers from the viewpoint of crack closure.

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.

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)

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.

Ion exchange fiber by radiation grafting, 1

International Nuclear Information System (INIS)

Fujiwara, Kunio

1990-01-01

Radiation grafting is gaining attention as a method for producing high performance materials. This method can be applied to add functions to existing polymer plastics. The author participated in the research program on the production of ion exchange fiber by radiation grafting and its applicability at the Japan Atomic Energy Research Institute, Takasaki Radiation Chemistry Research Establishment. Consequently, it was clarified that it was possible to introduce the cation exchange group, represented by sulfonic and carboxyl groups, and the anion exchange group, represented by the quarternary ammonium group, to polypropylene fiber available on the market. The ion exchange capacity was able to be controlled by the degree of grafting, i.e. approximately up to 3 meq/g in both strong acid and strong base and approximately up to 5 meq/g in weak acid were obtained. The adsorption performance of ammonia, a representative malodorous substance, was also studied using test cation exchange fiber. The adsorption rate of H type strong acid cation exchange fiber was great, due to the H type having neutral reaction, and the adsorption capacity matched the ion exchange capacity. Although the Cu and Ni types features coordinated adsorption and their adsorption rates were from 1/2 to 1/3 of that of the H type, their adsorption capacities showed increase along with the metal adsorbed. (author)

The decrease in technogenic load on the environment during the process of absorption of ammonia in soda industry

Directory of Open Access Journals (Sweden)

V. F. Moiseev

2016-12-01

Full Text Available The article studies the effectiveness of implementation of existing equipment of soda production absorbers for ammonia cleaning from gas emissions. It identifies the major sources of ammonia emissions in the soda ash production and the limitations of the existing equipment. Protection of air basin from pollution by industrial emissions is one of the most important problems of our time, which covers in one way or another almost all countries, regardless of their level of industrial development. It does not recognize territorial boundaries. Therefore, the creation of new designs of equipment for cleaning, improvement of the existing gascleaning equipment is the only way of increasing volumes of economic activities and expansion of production. The article analysis of equipment and performance of the absorption apparatus andmotivatethe creation a new design of a vortex apparatus with improved cleaning efficiency, reduced the production areaenergy costs of the cleaning process.

Superconducting properties and uniaxial strain characteristics of Nb3Sn fiber-reinforced superconductors with tantalum reinforcement fibers

International Nuclear Information System (INIS)

Arai, Kazuaki; Umeda, Masaichi; Agatsuma, Koh; Tateishi, Hiroshi

1998-01-01

We have been developing fiber-reinforced superconductors (FRS) for high-field and large-scale magnets. Tungsten fibers have been selected as the reinforcement fiber for FRS so far because tungsten has the highest elastic modulus of approximately 400 GPa which can minimize the strain from electromagnetic force. The preparation process of FRS consists of sputtering deposition and heat treatment because it may be difficult to apply drawing methods to materials of high-elastic modulus such as tungsten. Tantalum has high elastic modulus of 178 GPa and its thermal expansion coefficient that is closer to that of Nb 3 Sn than tungsten's, which means prestrain in Nb 3 Sn in FRS is reduced by adopting tantalum fibers. Tantalum has been used as barriers between bronze and copper in conventional Nb 3 Sn superconductors which are usually prepared with drawing process despite of the tantalum's high elastic modulus. That implies drawing process may be applied to prepare FRS with tantalum reinforcement fibers. In this paper, FRS using tantalum fibers prepared with sputtering process are described with making comparison with FRS of tungsten to clarify the basic properties of FRS using tantalum fibers. Depth profiles in Nb 3 Sn layer in FRS were measured to examine reaction between superconducting layers and reinforcement fibers. Superconducting properties including strain and stress characteristics were shown. Those data will contribute to design of FRS using tantalum reinforcement fibers with adopts the drawing processes. (author)

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

Release of ammonia from HAN-type PHA

International Nuclear Information System (INIS)

Zamecnik, J.R.

1992-01-01

A preliminary design basis for ammonia scrubbers in the DWPF has been issued. This design basis is based on a theoretical model of ammonia evolution from the SRAT, SME and RCT. It is desirable to acquire actual process data on ammonia evolution prior to performing detailed design of scrubbers for DWPF. The evolution of ammonia from the SRAT and SME in the Integrated DWPF Melter System (IDMS) was investigated during the HM4 run. In this run, Precipitate Hydrolysis Aqueous (PHA), which was made in the Precipitate Hydrolysis Experimental Facility (PHEF) using the HAN (hydroxylamine nitrate) process was used, thus resulting in PHA with a high concentration of ammonium ion

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.

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...

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.

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.

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

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.

Polymer fiber detectors for photoacoustic imaging

Science.gov (United States)

Grün, Hubert; Berer, Thomas; Pühringer, Karoline; Nuster, Robert; Paltauf, Günther; Burgholzer, Peter

2010-02-01

Photoacoustic imaging is a novel imaging method for medical and biological applications, combining the advantages of Diffuse Optical Imaging (high contrast) and Ultrasonic Imaging (high spatial resolution). A short laser pulse hits the sample. The absorbed energy causes a thermoelastic expansion and thereby launches a broadband ultrasonic wave (photoacoustic signal). The distribution of absorbed energy density is reconstructed from measurements of the photoacoustic signals around the sample. For collecting photoacoustic signals either point like or extended, integrating detectors can be used. The latter integrate the pressure at least in one dimension, e.g. along a line. Thereby, the three dimensional imaging problem is reduced to a two dimensional problem. For a tomography device consisting of a scanning line detector and a rotating sample, fiber-based detectors made of polymer have been recently introduced. Fiber-based detectors are easy to use and possess a constant, high spatial resolution over their entire active length. Polymer fibers provide a better impedance matching and a better handling compared with glass fibers which were our first approach. First measurement results using polymer fiber detectors and some approaches for improving the performance are presented.

Research on fiber-optic cantilever-enhanced photoacoustic spectroscopy for trace gas detection

Science.gov (United States)

Chen, Ke; Zhou, Xinlei; Gong, Zhenfeng; Yu, Shaochen; Qu, Chao; Guo, Min; Yu, Qingxu

2018-01-01

We demonstrate a new scheme of cantilever-enhanced photoacoustic spectroscopy, combining a sensitivity-improved fiber-optic cantilever acoustic sensor with a tunable high-power fiber laser, for trace gas detection. The Fabry-Perot interferometer based cantilever acoustic sensor has advantages such as high sensitivity, small size, easy to install and immune to electromagnetic. Tunable erbium-doped fiber ring laser with an erbium-doped fiber amplifier is used as the light source for acoustic excitation. In order to improve the sensitivity for photoacoustic signal detection, a first-order longitudinal resonant photoacoustic cell with the resonant frequency of 1624 Hz and a large size cantilever with the first resonant frequency of 1687 Hz are designed. The size of the cantilever is 2.1 mm×1 mm, and the thickness is 10 μm. With the wavelength modulation spectrum and second-harmonic detection methods, trace ammonia (NH3) has been measured. The gas detection limits (signal-to-noise ratio = 1) near the wavelength of 1522.5 nm is achieved to be 3 ppb.

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.

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

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.

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

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.

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.

A Feasibility Study of Ammonia Recovery from Coking Wastewater by Coupled Operation of a Membrane Contactor and Membrane Distillation

Directory of Open Access Journals (Sweden)

Po-Hsun Lin

2018-03-01

Full Text Available More than 80% of ammonia (NH3 in the steel manufacturing process wastewater is contributed from the coking wastewater, which is usually treated by biological processes. However, the NH3 in the coking wastewater is typically too high for biological treatment due to its inhibitory concentration. Therefore, a two-stage process including a hollow fiber membrane contactor (HFMC and a modified membrane distillation (MD system was developed and applied to reduce and recover NH3 from coking wastewater. The objectives of this paper are to evaluate different membrane materials, receiving solutions, and operation parameters for the system, remove NH3 from the coking wastewater to less than 300 mg N/L, which is amenable to the biological process, and recover ammonia solution for reuse. As a result, the polytetrafluoroethylene (PTFE HFMC using sulfuric acid as a receiving solution can achieve a maximum NH3-N transmembrane flux of 1.67 g N/m2·h at pH of 11.5 and reduce NH3 in the coking wastewater to less than 300 mg N/L. The NH3 in the converted ammonium sulfate ((NH42SO4 was then recovered by the modified MD using ice water as the receiving solution to produce ≥3% of ammonia solution for reuse.

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.

Gas sensing based on detection of light radiation from a region of modified cladding (nanocrystalline ZnO) of an optical fiber

Science.gov (United States)

Devendiran, S.; Sastikumar, D.

2017-03-01

A new type of fiber optic gas sensor is proposed by detecting a light radiated from a region of cladding modified with metal oxide (nanocrystalline ZnO). The intensity of radiated light is found to vary with different gasses and concentrations. Sensing characteristics are studied for ammonia, methanol, ethanol and acetone gasses. Gas sensitivity of the proposed sensor is compared with clad-modified fiber optic gas sensor. The new sensor exhibits enhanced sensitivity. Time response characteristics of the sensor are reported.

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.

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

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 solar absorption refrigeration system operating with the mixture ammonia-lithium nitrate

Energy Technology Data Exchange (ETDEWEB)

Rivera, W.; Martinez, F.; Garcia-Valladares, O. [Centro de Investigacion en Energia de la Univ. Nacional Autonoma de Mexico, Mor (Mexico); Rivera, C.O. [Univ. Veracruzana, Campus Coatzacoalcos (Mexico)

2007-07-01

An intermittent solar absorption refrigeration system for ice production operating with the ammonia-lithium nitrate mixture has been developed in the Centro de Investigacion en Energia of the Universidad Nacional Autonoma de Mexico. The system consists basically of a compound parabolic concentrator (CPC), a generator-absorber, a condenser, a condensate tank, an expansion valve and an evaporator. The system was evaluated in sunny days with insolations above 20 MJ/m{sup 2}-day at different condenser temperatures. The generator temperatures varied from 108 to 121 C and the evaporator temperatures inside the camera from -8 to 0 C. The coefficients of performance (COP) varied from 0.13 to 0.26 depending of the operating temperatures of the system and the solar irradiation. (orig.)

Multivariable optimization of an auto-thermal ammonia synthesis reactor using genetic algorithm

Science.gov (United States)

Anh-Nga, Nguyen T.; Tuan-Anh, Nguyen; Tien-Dung, Vu; Kim-Trung, Nguyen

2017-09-01

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 optimal problem requires the maximization of a multivariable objective function which subjects to a number of equality constraints involving the solution of coupled differential equations and also inequality constraints. The solution of an optimization problem can be found through, among others, deterministic or stochastic approaches. The stochastic methods, such as evolutionary algorithm (EA), which is based on natural phenomenon, can overcome the drawbacks such as the requirement of the derivatives of the objective function and/or constraints, or being not efficient in non-differentiable or discontinuous problems. Genetic algorithm (GA) which is a class of EA, exceptionally simple, robust at numerical optimization and is more likely to find a true global optimum. In this study, the genetic algorithm is employed to find the optimum profit of the process. The inequality constraints were treated using penalty method. The coupled differential equations system was solved using Runge-Kutta 4th order method. The results showed that the presented numerical method could be applied to model the ammonia synthesis reactor. The optimum economic profit obtained from this study are also compared to the results from the literature. It suggests that the process should be operated at higher temperature of feed gas in catalyst zone and the reactor length is slightly longer.

Fiber Optic Sensors For Detection of Toxic and Biological Threats

Directory of Open Access Journals (Sweden)

Jianming Yuan

2007-12-01

Full Text Available Protection of public and military personnel from chemical and biological warfareagents is an urgent and growing national security need. Along with this idea, we havedeveloped a novel class of fiber optic chemical sensors, for detection of toxic and biologicalmaterials. The design of these fiber optic sensors is based on a cladding modificationapproach. The original passive cladding of the fiber, in a small section, was removed and thefiber core was coated with a chemical sensitive material. Any change in the opticalproperties of the modified cladding material, due to the presence of a specific chemicalvapor, changes the transmission properties of the fiber and result in modal powerredistribution in multimode fibers. Both total intensity and modal power distribution (MPDmeasurements were used to detect the output power change through the sensing fibers. TheMPD technique measures the power changes in the far field pattern, i.e. spatial intensitymodulation in two dimensions. Conducting polymers, such as polyaniline and polypyrrole,have been reported to undergo a reversible change in conductivity upon exposure tochemical vapors. It is found that the conductivity change is accompanied by optical propertychange in the material. Therefore, polyaniline and polypyrrole were selected as the modifiedcladding material for the detection of hydrochloride (HCl, ammonia (NH3, hydrazine(H4N2, and dimethyl-methl-phosphonate (DMMP {a nerve agent, sarin stimulant},respectively. Several sensors were prepared and successfully tested. The results showeddramatic improvement in the sensor sensitivity, when the MPD method was applied. In thispaper, an overview on the developed class of fiber optic sensors is presented and supportedwith successful achieved results.

Faraday rotation influence factors in tellurite-based glass and fibers

Energy Technology Data Exchange (ETDEWEB)

Chen, Qiuling; Wang, Qingwei [Henan University of Technology, School of Materials Science and Engineering, Zhengzhou, Henan (China); Wang, Hui; Chen, Qiuping [Politecnico di Torino, Department of Applied Science and Technology, Turin (Italy)

2015-09-15

The Faraday rotation influence factors in tellurite-based glass and fibers were studied by experiments and simulations. TeO{sub 2}-ZnO-Na{sub 2}O-BaO glass family was fabricated and characterized in terms of the thermal and magneto-optical properties. Two core-cladding pairs for two fibers were selected from fabricated glasses. The Verdet constants of the glasses and fibers were measured at different wavelengths using a homemade optical bench, and the Verdet constant of fiber was close to that of the bulk glass. The influence from external factors (wavelength, laser power and magnetic field) and internal factors (thermal expansion coefficient difference, refractive index and Verdet constant of core and cladding) on Faraday rotation in fibers was investigated and discussed, and the purpose of this study is to improve the Faraday rotation in tellurite fibers for MO device applications both from internal material property match and external parameter configuration in measurement. (orig.)

Faraday rotation influence factors in tellurite-based glass and fibers

International Nuclear Information System (INIS)

Chen, Qiuling; Wang, Qingwei; Wang, Hui; Chen, Qiuping

2015-01-01

The Faraday rotation influence factors in tellurite-based glass and fibers were studied by experiments and simulations. TeO 2 -ZnO-Na 2 O-BaO glass family was fabricated and characterized in terms of the thermal and magneto-optical properties. Two core-cladding pairs for two fibers were selected from fabricated glasses. The Verdet constants of the glasses and fibers were measured at different wavelengths using a homemade optical bench, and the Verdet constant of fiber was close to that of the bulk glass. The influence from external factors (wavelength, laser power and magnetic field) and internal factors (thermal expansion coefficient difference, refractive index and Verdet constant of core and cladding) on Faraday rotation in fibers was investigated and discussed, and the purpose of this study is to improve the Faraday rotation in tellurite fibers for MO device applications both from internal material property match and external parameter configuration in measurement. (orig.)

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...

Expansion and functional properties of extruded snacks enriched with nutrition sources from food processing by-products

OpenAIRE

Korkerd, Sopida; Wanlapa, Sorada; Puttanlek, Chureerat; Uttapap, Dudsadee; Rungsardthong, Vilai

2015-01-01

Rich sources of protein and dietary fiber from food processing by-products, defatted soybean meal, germinated brown rice meal, and mango peel fiber, were added to corn grit at 20 % (w/w) to produce fortified extruded snacks. Increase of total dietary fiber from 4.82 % (wb) to 5.92–17.80 % (wb) and protein from 5.03 % (wb) to 5.46–13.34 % were observed. The product indicated high expansion and good acceptance tested by sensory panels. There were 22.33–33.53 and 5.30–11.53 fold increase in the ...

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

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.

Carbon Fiber Mirror for a CubeSat Telescope

Science.gov (United States)

Kim, Young-Soo; Jang, Jeong Gyun; Kim, Jihun; Nam, Uk Won

2017-08-01

Telescope mirrors made by carbon fibers have been increasingly used especially for space applications, and they may replace the traditional glass mirrors. Glass mirrors are easy to fabricate, but needed to be carefully handled as they are brittle. Other materials have also been considered for telescope mirrors, such as metals, plastics, and liquids even. However glass and glass ceramics are still commonly and dominantly used.Carbon fiber has mainly been used for mechanical supports like truss structure and telescope tubes, as it is stiff and light-weight. It can also be a good material for telescope mirrors, as it has additional merits of non-brittle and very low thermal expansion. Therefore, carbon fiber mirror would be suitable for space telescopes which should endure the harsh vibration conditions during launch.A light-weight telescope made by carbon fiber has been designed for a small satellite which would have much less weight than conventional ones. In this poster, mirror materials are reviewed, and a design of carbon fiber telescope is presented and discussed.

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.

Compositional changes in swine manure fibers treated with aqueous ammonia soaking (AAS) resulting in increased methane potential

OpenAIRE

Jurado, Esperanza; Hansen, Mads A.T.; Gavala, Hariklia N.; Skiadas, Ioannis

2013-01-01

AAS treatment is a very efficient method to increase the methane potential of manure fibers. The chemical composition and supramolecular structures of swine manure fibers before and after AAS treatment was investigated in this study. Composition analyses, atomic force microscopy (AFM), scanning electron microscopy (SEM), and chemical surface composition by Attenuated Total Reflectance–Fourier Transform Infrared (ATR–FTIR) showed that no delignification of the lignocellulose took place during ...

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.

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.

Strain and temperature measurement in pultrusion processes by fiber Bragg grating sensors

Science.gov (United States)

Tucci, Fausto; Rubino, Felice; Carlone, Pierpaolo

2018-05-01

Injection Pultrusion (IP) is one of the most effective processes, in terms of productivity and costs, to manufacture fiber reinforced polymers. In IP roving of fiber are driven through an injection chamber in which they are impregnated by the resin and then formed in a shaped die. The die is heated in order to cure the resin. Pultruded products are in most cases characterized by constant cross-section profile, whereas unidirectional long fibers are mainly used as reinforcing material. Two relevant phenomena occur within the injection chamber and the heated die, namely the impregnation of the fibers and the polymerization of the resin. Furthermore, thermal expansion, resin chemical shrinkage and the interaction between the die and the impregnated fibers strongly influence the process [1]. Clearly, thermal and mechanical fields significantly impact on these strictly chained behaviours. The use of thermocouples to evaluate temperature within pultrusion die is already widespread, but they are not capable to acquire any information concerning stress-strain levels. In the present work Fibers Bragg Gratings (FBG) sensors were used to measure thermal and strain profiles in selected material location within the injection chamber and the curing die. Being the differences among the spectres transmitted and received are related to the variations in both temperature and strain, commercial FBG sensors were opportunely modified and calibrated. The optical fibers were hooked to the fibers entering into the injection pultrusion die. Taking the pulling speed into account, each waveform acquired was correlated to a position within the die. Obtained data highlight the effect of the heat generation due to resin reaction as well as longitudinal strains related to the pulling force, the thermal expansion and the chemical shrinkage of the resin system.

Fused-fiber-based 3-dB mode insensitive power splitters for few-mode optical fiber networks

Science.gov (United States)

Ren, Fang; Huang, Xiaoshan; Wang, Jianping

2017-11-01

We propose a 3-dB mode insensitive power splitter (MIPS) capable of broadcasting and combining optical signals. It is fabricated with two identical few-mode fibers (FMFs) by a heating and pulling technique. The mode-dependent power transfer characteristic as a function of pulling length is investigated. For exploiting its application, we experimentally demonstrate both FMF-based transmissive and reflective star couplers consisting of multiple 3-dB mode insensitive power splitters, which perform broadcasting and routing signals in few-mode optical fiber networks such as mode-division multiplexing (MDM) local area networks using star topology. For experimental demonstration, optical on-off keying signals at 10 Gb/s carried on three spatial modes are successfully processed with open and clear eye diagrams. Measured bit error ratio results show reasonable power penalties. It is found that a reflective star coupler in MDM networks can reduce half of the total amount of required fibers comparing to that of a transmissive star coupler. This MIPS is more efficient, more reliable, more flexible, and more cost-effective for future expansion and application in few-mode optical fiber networks.

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.

Influence of thermal cycling on flexural properties of composites reinforced with unidirectional silica-glass fibers.

Science.gov (United States)

Meriç, Gökçe; Ruyter, I Eystein

2008-08-01

The purpose was to investigate the effect of water storage and thermal cycling on the flexural properties of differently sized unidirectional fiber-reinforced composites (FRCs) containing different quantities of fibers. The effect of fiber orientation on the thermal expansion of FRCs as well as how the stresses in the composites can be affected was considered. An experimental polymeric base material was reinforced with silica-glass fibers. The cleaned and silanized fibers were sized with either linear PBMA-size or crosslinked PMMA-size. For the determination of flexural properties and water uptake, specimens were processed with various quantities of differently sized unidirectional fibers. Water uptake of FRC was measured. Water immersed specimens were thermally cycled for 500 and 12,000 cycles (5 degrees C/55 degrees C). Flexural properties of "dry" and wet specimens with and without thermal cycling were determined by a three-point bending test. The linear coefficients of thermal expansion (LCTE) for FRC samples with different fiber orientations were determined using a thermomechanical analyzer. Water uptake of the FRC specimens increased with a decrease in fiber content of the FRC. Flexural properties of FRCs improved with increasing fiber content, whereas the flexural properties were not influenced significantly by water and thermal cycling. Fiber orientation had different effects on LCTE of FRCs. Unidirectional FRCs had two different LCTE in longitudinal and transverse directions whereas bidirectional FRCs had similar LCTE in two directions and a higher one in the third direction. The results of the study suggest that the surface-treated unidirectional silica-glass FRC can be used for long-term clinical applications in the oral cavity.

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

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.

Effect of a high-protein, high-fiber diet plus supplementation with branched-chain amino acids on the nutritional status of patients with cirrhosis

Directory of Open Access Journals (Sweden)

A. Ruiz-Margáin

2018-01-01

Conclusion: Supplementation with branched-chain amino acids plus a high-fiber, high-protein diet is a safe intervention in patients with cirrhosis. It helps increase muscle mass and does not raise the levels of ammonia or glucose, nor is it associated with the development of hepatic encephalopathy.

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...

Ytterbium-Phosphate Glass for Microstructured Fiber Laser

Directory of Open Access Journals (Sweden)

Ryszard Stępień

2014-06-01

Full Text Available In the paper, we report on the development of a synthesis and melting method of phosphate glasses designed for active microstructured fiber manufacturing. Non-doped glass synthesized in a P2O5-Al2O3-BaO-ZnO-MgO-Na2O oxide system served as the matrix material; meanwhile, the glass was doped with 6 mol% (18 wt% of Yb2O3, as fiber core. The glasses were well-fitted in relation to optical (refractive index and thermal proprieties (thermal expansion coefficient, rheology. The fiber with the Yb3+-doped core, with a wide internal photonic microstructure for a laser pump, as well as with a high relative hole size in the photonic outer air-cladding, was produced. The laser built on the basis of this fiber enabled achieving 8.07 W of output power with 20.5% slope efficiency against the launched pump power, in single-mode operation M2 = 1.59, from a 53 cm-long cavity.

Photonic crystal fiber sensing characteristics research based on alcohol asymmetry filling

Science.gov (United States)

Shi, Fu-quan; Luo, Yan; Li, Hai-tao; Peng, Bao-jin

2018-02-01

A new type of Sagnac fiber temperature sensor based on alcohol asymmetric filling photonic crystal fiber is proposed. First, the corrosion of photonic crystal fiber and the treatment of air hole collapse are carried out. Then, the asymmetric structure of photonic crystal fiber is filled with alcohol, and then the structure is connected to the Sagnac interference ring. When the temperature changes, the thermal expansion effect of filling alcohol will lead to the change of birefringence of photonic crystal fiber, so that the interference spectrum of the sensor will drift along with the change of temperature. The experimental results show that the interference red shift will occur with the increase of temperature, and the temperature sensitivity is 0.1864nm/ °C. The sensor has high sensitivity to temperature. At the same time, the structure has the advantages of high stability, anti electromagnetic interference and easy to build. It provides a new method for obtaining birefringence in ordinary photonic crystal fibers.

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.

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.

Plasmophore sensitized imaging of ammonia release from biological tissues using optodes

International Nuclear Information System (INIS)

Stroemberg, Niklas; Hakonen, Aron

2011-01-01

Highlights: → A plasmophore sensitized optode for imaging ammonia (NH 3 ) concentrations in muscle tissues was developed. → Ammonia concentrations ranging from 10 nM and upwards can be quantified reversibly with an optical resolution of 127 μm. → The general sensing scheme offers new possibilities for the development of artificial optical noses and tongues. - Abstract: A plasmophore sensitized optode was developed for imaging ammonia (NH 3 ) concentrations in muscle tissues. The developed ammonia sensor and an equivalent non plasmophore version of the sensor were tested side by side to compare their limit of detection, dynamic range, reversibility and overall imaging quality. Bio-degradation patterns of ammonia release from lean porcine skeletal muscle were studied over a period of 11 days. We demonstrate that ammonia concentrations ranging from 10 nM can be quantified reversibly with an optical resolution of 127 μm in a sample area of 25 mm x 35 mm. The plasmophore ammonia optode showed improved reversibility, less false pixels and a 2 nM ammonia detection limit compared to 200 nM for the non-plasmophore sensor. Main principles of the sensing mechanism include ammonia transfer over a gas permeable film, ammonia protonation, nonactin facilitated merocyanine-ammonium coextraction and plasmophore enhancement. The vast signal improvement is suggested to rely on solvatochroism, nanoparticle scattering and plasmonic interactions that are utilized constructively in a fluorescence ratio. In addition to fundamental medicinal and biological research applications in tissue physiology, reversible ammonia quantification will be possible for a majority of demanding imaging and non imaging applications such as monitoring of low ammonia background concentrations in air and non-invasive medicinal diagnosis through medical breath or saliva analysis. The nanoparticle doped sensor constitutes a highly competitive technique for ammonia sensing in complex matrixes and the

Carbon Fiber Reinforced Carbon Composites Rotary Valves for Internal Combustion Engines

Science.gov (United States)

Northam, G. Burton (Inventor); Ransone, Philip O. (Inventor); Rivers, H. Kevin (Inventor)

1999-01-01

Carbon fiber reinforced carbon composite rotary, sleeve, and disc valves for internal combustion engines and the like are disclosed. The valves are formed from knitted or braided or warp-locked carbon fiber shapes. Also disclosed are valves fabricated from woven carbon fibers and from molded carbon matrix material. The valves of the present invention with their very low coefficient of thermal expansion and excellent thermal and self-lubrication properties, do not present the sealing and lubrication problems that have prevented rotary, sleeve, and disc valves from operating efficiently and reliably in the past. Also disclosed are a sealing tang to further improve sealing capabilities and anti-oxidation treatments.

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.)

Method for releasing hydrogen from ammonia borane

Science.gov (United States)

Varma, Arvind; Diwan, Moiz; Shafirovich, Evgeny; Hwang, Hyun-Tae; Al-Kukhun, Ahmad

2013-02-19

A method of releasing hydrogen from ammonia borane is disclosed. The method comprises heating an aqueous ammonia borane solution to between about 80-135.degree. C. at between about 14.7 and 200 pounds per square inch absolute (psia) to release hydrogen by hydrothermolysis.

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...

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

REDUCING AMMONIA CONCENTRATIONS IN ATMOSPHERE AFTER ITS UNPLANNED RELEASE

Directory of Open Access Journals (Sweden)

L. V. Amelina

2017-08-01

Full Text Available Purpose. The aim of this work is development of numerical model, which allows to calculate the efficiency of neutralizer supply for reduction of air pollution in case of unplanned ammonia emission at the territory of ammonia pump station. The numerical model should allow fast calculating, taking into account the meteorological parameters and buildings situated near the source of toxic chemical emission and equipment for neutralizer supply. Methodology. The developed model is based on the equation for potential flow and equation of pollutant dispersion. To simulate the chemical interaction between ammonia and neutralizer the stoichiometry equation is used. Equation of potential flow is used to compute flow pattern among buildings. To solve the equation for potential flow the Samarskii implicit difference scheme is used. The implicit change-triangle difference scheme is used to solve equation of mass transfer. While for the numerical integration the authors use the rectangular difference grid. Method of porosity technique («markers method» is applied to create the form of comprehensive computational region. Emission of ammonia is modeled using Delta function for point source. Findings. Developed numerical model belongs to the class of «diagnostic models». This model takes into account the main physical factors affecting the process of dispersion of ammonia and neutralizer in the atmosphere, as well as the influence of buildings on admixture dispersion. On the basis of the developed numerical models the authors carried out a computational experiment to estimate the efficiency of neutralizer supply for reduction of air pollution in case of unplanned ammonia release at ammonia pump station. Originality. Developed numerical model allows calculating the flow pattern among buildings and estimating the efficiency of neutralizer supply for reduction of air pollution in the case unplanned ammonia release. Practical value. Model allows performing fast

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.

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.

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....

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.

[Application of Raman spectroscopy to investigation of CVD-SIC fiber].

Science.gov (United States)

Liu, Bin; Yang, Yan-Qing; Luo, Xian; Huang, Bin

2011-11-01

The CVD-SiC fiber was studied by using laser Raman spectra. It was found that the sharp TO peak exists in the first SiC deposit layer, indicating the larger SiC grains. But the second SiC deposit layer is with small grains. Raman peak of carbon and silicon was detected respectively in the first and second layer. Compared with that of the single SiC fiber, the TO peaks move to the high wave number for the SiC fiber in SiC(f)/Ti-6Al-4V composite. It indicates that the compressive thermal residual stress is present in the SiC fiber during the fabrication of the composite because of the mismatched coefficient of thermal expansion between Ti-6Al-4V matrix and SiC fiber. The average thermal residual stress of the SiC fiber in SiC(f)/Ti-6Al-4V composite was calculated to be 318 MPa and the residual stress in first deposit layer is 436 MPa which is much higher than that in the second layer.

Thermal stress control using waste steel fibers in massive concretes

Science.gov (United States)

Sarabi, Sahar; Bakhshi, Hossein; Sarkardeh, Hamed; Nikoo, Hamed Safaye

2017-11-01

One of the important subjects in massive concrete structures is the control of the generated heat of hydration and consequently the potential of cracking due to the thermal stress expansion. In the present study, using the waste turnery steel fibers in the massive concretes, the amount of used cement was reduced without changing the compressive strength. By substituting a part of the cement with waste steel fibers, the costs and the generated hydration heat were reduced and the tensile strength was increased. The results showed that by using 0.5% turnery waste steel fibers and consequently, reducing to 32% the cement content, the hydration heat reduced to 23.4% without changing the compressive strength. Moreover, the maximum heat gradient reduced from 18.5% in the plain concrete sample to 12% in the fiber-reinforced concrete sample.

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.

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

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 ...

Calculation notes in support of ammonia releases from waste tank ventilation systems

International Nuclear Information System (INIS)

Wojdac, L.F.

1996-01-01

Ammonia is generated in waste tanks via the degradation of nitrogen compounds. The ammonia is released from the liquids by a mechanism which is dependent on temperature, pH, ionic strength and ammonia concentration. The release of ammonia to the environment occurs via diffusion of ammonia through a stagnant air mass and into the ventilation system

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.

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

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.

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

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

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

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.

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

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...

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 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.

Evaluation of the potential for significant ammonia releases from Hanford waste tanks

International Nuclear Information System (INIS)

Palmer, B.J.; Anderson, C.M.; Chen, G.; Cuta, J.M.; Ferryman, T.A.; Terrones, G.

1996-07-01

Ammonia is ubiquitous as a component of the waste stored in the Hanford Site single-shell tanks (SSTs) and double-shell tanks (DSTs). Because ammonia is both flammable and toxic, concerns have been raised about the amount of ammonia stored in the tanks and the possible mechanisms by which it could be released from the waste into the head space inside the tanks as well as into the surrounding atmosphere. Ammonia is a safety issue for three reasons. As already mentioned, ammonia is a flammable gas and may contribute to a flammability hazard either directly, if it reaches a high enough concentration in the tank head space, or by contributing to the flammability of other flammable gases such as hydrogen (LANL 1994). Ammonia is also toxic and at relatively low concentrations presents a hazard to human health. The level at which ammonia is considered Immediately Dangerous to Life or Health (IDLH) is 300 ppm (WHC 1993, 1995). Ammonia concentrations at or above this level have been measured inside the head space in a number of SSTs. Finally, unlike hydrogen and nitrous oxide, ammonia is highly soluble in aqueous solutions, and large amounts of ammonia can be stored in the waste as dissolved gas. Because of its high solubility, ammonia behaves in a qualitatively different manner from hydrogen or other insoluble gases. A broader range of scenarios must be considered in modeling ammonia storage and release

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.

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.

Carbon Fiber Reinforced Carbon Composite Rotary Valve for an Internal Combustion Engine

Science.gov (United States)

Northam, G.Burton (Inventor); Ransone, Philip O. (Inventor); Rivers, H. Kevin (Inventor)

2000-01-01

Carbon fiber reinforced carbon composite rotary sleeve, and disc valves for internal combustion engines and the like are disclosed. The valves are formed from knitted or braided or wrap-locked carbon fiber shapes. Also disclosed are valves fabricated from woven carbon fibers and from molded carbon matrix material. The valves of the present invention with their very low coefficient of thermal expansion and excellent thermal and self-lubrication properties do not present the sealing and lubrication problems that have prevented rotary sleeve and disc valves from operating efficiently and reliably in the past. Also disclosed are a sealing tang to further improve sealing capabilities and anti-oxidation treatments.

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.

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...

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

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...

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.

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.

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.

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.)

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

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

Ammonia Release on ISS

Science.gov (United States)

Macatangay, Ariel

2009-01-01

Crew: Approximately 53% metabolic load Product of protein metabolism Limit production of ammonia by external regulation NOT possbile Payloads Potential source Scientific experiments Thorough safety review ensures sufficient levels of containment

A study on ammonia removal properties using clinoptilolite Part 1 : characterization of clinoptilolite and ammonia removal properties in batch reactor

Energy Technology Data Exchange (ETDEWEB)

Moon, Jeong Min; Chung, Jong Shik [Dept. of Chemical Engineering/School of Environment Engineering, Pohang University of Science and Technology, Pohang (Korea); Sun, De Shi [Dept. of Applied Chemistry, Harbin Institute of Techonology (China)

2000-04-01

A natural zeolite, deposit located at Guryongpo, Young-il bay, was found to be clinoptilolite containing impurities of heulandite and mordenite. Cation exchange capacity(CEC) for ammonia was about 1.41 meq/g from Na{sup +}-form of the zeolite. In batch experiment, removal efficiency of ammonia was increased as particle size of zeolite and initial concentration of Na{sup +} were decreased and SR(Stoichiometric Ratio), time, and initial concentration of ammonia increased. More than 70% aluminum ion could be removed from water having 3 ppm ammonia and 0.7 ppm Al{sup 3+} by the batch adsorption(ion exchange) experiment. Regeneration of used zeolite with NaCl solution of pH=12 has shown more than 95% of regeneration efficiency when SR'(ratio of the amount of NaCl solution employed actually to the amount in a stoichiometric quantity) was equal to 2.0. 19 refs., 10 figs., 1 tab.

Atmospheric Fate and Transport of Agricultural Dust and Ammonia

Science.gov (United States)

Hiranuma, N.; Brooks, S. D.; Thornton, D. C.; Auvermann, B. W.; Fitz, D. R.

2008-12-01

Agricultural fugitive dust and odor are significant sources of localized air pollution in the semi-arid southern Great Plains. Daily episodes of ground-level fugitive dust emissions from the cattle feedlots associated with increased cattle activity in the early evenings are routinely observed, while consistently high ammonia is observed throughout the day. Here we present measurements of aerosol size distributions and concentrations of gas and particulate phase ammonia species collected at a feedlot in Texas during summers of 2006, 2007 and 2008. A GRIMM sequential mobility particle sizer and GRIMM 1.108 aerosol spectrometer were used to determine aerosol size distributions in the range of 10 nm to 20 µm aerodynamic diameter at the downwind and upwind edges of the facility. Using aqueous scrubbers, simultaneous measurements of both gas phase and total ammonia species present in the gas and particle phases were also collected. In addition to the continuous measurements at the edges of the facility, coincident aerosol and ammonia measurements were obtain at an additional site further downwind (~3.5 km). Taken together our measurements will be used to quantify aerosol and ammonia dispersion and transport. Relationships between the fate and transport of the aerosols and ammonia will be discussed.

Investigations of blood ammonia analysis: Test matrices, storage, and stability.

Science.gov (United States)

Goldstein, Brittany N; Wesler, Jordan; Nowacki, Amy S; Reineks, Edmunds; Natowicz, Marvin R

2017-06-01

An assessment of blood ammonia concentration is common medical practice in the evaluation of an individual with an unexplained mental status change or coma. The determination of a blood ammonia level is most commonly done using a glutamate dehydrogenase (GLDH)-based assay, although there are many potential sources of artifact and the literature is inconsistent regarding key preanalytic issues. Using a GLDH-based assay, we first investigated matrix effects using three anticoagulants: heparin, EDTA and oxalate. Heparin-anticoagulated plasma was substantially less precise than EDTA- and oxalate-anticoagulated plasma. Oxalate-anticoagulated plasma showed a greater baseline of apparent ammonia than either heparin- or EDTA-derived plasma, presumably due to interferants. We then evaluated the stability of EDTA-anticoagulated plasma for assessment of ammonia when stored at 4°C,-14°C or -70°C. There was a linear increase of ammonia with storage at both 4°C and -14°C. Plasma kept at -70°C for up to three weeks showed no change in measured ammonia relative to the baseline determination. This work clarifies preanalytic conditions for which a precise determination of ammonia can be accomplished using a GLDH-based assay. Copyright © 2017 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

Statistics of Microstructure, Peak Stress and Interface Damage in Fiber Reinforced Composites

DEFF Research Database (Denmark)

Kushch, Volodymyr I.; Shmegera, Sergii V.; Mishnaevsky, Leon

2009-01-01

This paper addresses an effect of the fiber arrangement and interactions on the peak interface stress statistics in a fiber reinforced composite material (FRC). The method we apply combines the multipole expansion technique with the representative unit cell model of composite bulk, which is able...... to simulate both the uniform and clustered random fiber arrangements. By averaging over a number of numerical tests, the empirical probability functions have been obtained for the nearest neighbor distance and the peak interface stress. It is shown that the considered statistical parameters are rather...... sensitive to the fiber arrangement, particularly cluster formation. An explicit correspondence between them has been established and an analytical formula linking the microstructure and peak stress statistics in FRCs has been suggested. Application of the statistical theory of extreme values to the local...

The production of ammonia by multiheme cytochromes C.

Science.gov (United States)

Simon, Jörg; Kroneck, Peter M H

2014-01-01

The global biogeochemical nitrogen cycle is essential for life on Earth. Many of the underlying biotic reactions are catalyzed by a multitude of prokaryotic and eukaryotic life forms whereas others are exclusively carried out by microorganisms. The last century has seen the rise of a dramatic imbalance in the global nitrogen cycle due to human behavior that was mainly caused by the invention of the Haber-Bosch process. Its main product, ammonia, is a chemically reactive and biotically favorable form of bound nitrogen. The anthropogenic supply of reduced nitrogen to the biosphere in the form of ammonia, for example during environmental fertilization, livestock farming, and industrial processes, is mandatory in feeding an increasing world population. In this chapter, environmental ammonia pollution is linked to the activity of microbial metalloenzymes involved in respiratory energy metabolism and bioenergetics. Ammonia-producing multiheme cytochromes c are discussed as paradigm enzymes.

Flexible concrete link slabs used as expansion joints in bridge decks

DEFF Research Database (Denmark)

Lárusson, Lárus Helgi; Fischer, Gregor

2011-01-01

of water through the expansion joint and subsequent corrosion of girders and girder bearings. Investigations on joint-less superstructures using conventional steel reinforcement in so-called concrete link slabs indicate improved performance and economic feasibility. However, this concept requires...... relatively large amounts of steel reinforcement for crack control purposes and consequently provides a relatively large flexural stiffness and negative moment capacity at the joint between the spans. These contradicting requirements and effects in existing replacement concepts for damaged mechanical bridge...... joints are currently unresolved. In the proposed system described in this paper, a ductile cement-based composite section reinforced with Glass Fiber Reinforced Polymers (GFRP) replaces the damaged expansion joint. The combination of this ductile concrete together with corrosion resistant GFRP...

Ammonia production from amino acid-based biomass-like sources by engineered Escherichia coli.

Science.gov (United States)

Mikami, Yosuke; Yoneda, Hisanari; Tatsukami, Yohei; Aoki, Wataru; Ueda, Mitsuyoshi

2017-12-01

The demand for ammonia is expected to increase in the future because of its importance in agriculture, industry, and hydrogen transportation. Although the Haber-Bosch process is known as an effective way to produce ammonia, the process is energy-intensive. Thus, an environmentally friendly ammonia production process is desired. In this study, we aimed to produce ammonia from amino acids and amino acid-based biomass-like resources by modifying the metabolism of Escherichia coli. By engineering metabolic flux to promote ammonia production using the overexpression of the ketoisovalerate decarboxylase gene (kivd), derived from Lactococcus lactis, ammonia production from amino acids was 351 mg/L (36.6% yield). Furthermore, we deleted the glnA gene, responsible for ammonia assimilation. Using yeast extract as the sole source of carbon and nitrogen, the resultant strain produced 458 mg/L of ammonia (47.8% yield) from an amino acid-based biomass-like material. The ammonia production yields obtained are the highest reported to date. This study suggests that it will be possible to produce ammonia from waste biomass in an environmentally friendly process.

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.

AMMONOX

DEFF Research Database (Denmark)

Lymperatou, Anna; Gavala, Hariklia N.; Esbensen, Kim Harry

2015-01-01

Laboratory experiments have shown that Aqueous Ammonia Soaking (AAS) is a very promising treatment for increasing the methane yield of the solid fraction of manure (fibers). AMMONOX is a new concept based on the sustainable use of ammonia for enhancing biogas production at biogas plants digesting...... manure. The proposed process is based on an optimized AAS treatment of manure fibers in combination with an efficient ammonia recovery step. The enhancement of biogas production is achieved by enriching manure with AAS-treated fibers or other lignocellulosic residues while the ammonia recovered can...... be used for fulfilling the needs of the treatment. Furthermore, excess of ammonia could be produced when ammonia is recovered from both the treated fibers and the digester effluent, which could be used for the reduction of NOx when the biogas produced is used for electricity generation by gas engines...

Stepwise dehydrogenation of ammonia on Fcc-Co surfaces: A DFT study

Energy Technology Data Exchange (ETDEWEB)

Ma, F.F.; Ma, S.H., E-mail: mash.phy@htu.edu.cn; Jiao, Z.Y.; Dai, X.Q.

2017-05-31

Highlights: • On Co surfaces, oxygen atom not only strengthens ammonia-substrate interaction but also facilitates ammonia dissociation on the Co surfaces. • Pre-adsorbed O atom significantly promotes the stepwise dehydrogenation of ammonia on Co(110), giving rise to N atom strongly binding with the surface. • The dissociation of NH appears to be the rate-determining step on O-covered Co(111) and Co(100) surfaces. • The species N and NH produced in ammonia dehydrogenation are likely responsible for cobalt catalyst deactivation in the excess of oxygen atom. - Abstract: The stepwise dehydrogenation of ammonia on clean and O-covered Co surfaces have been studied by performing density functional theory (DFT) calculations. It is found that the interaction of species NH{sub x} (x = 0–3) with the Co surfaces become stronger with its further dehydrogenation, and oxygen atom not only strengthens ammonia-substrate interaction but also facilitates ammonia dissociation. Specifically, pre-adsorbed O atom significantly promotes the stepwise dehydrogenation of ammonia on Co(110), giving rise to N atom strongly binding with the surface. In contrast, the dissociation of NH appears to be the rate-determining step on O-covered Co(111) and Co(100) surfaces, due to the high energy barriers. And present results demonstrate that the species N and NH produced in ammonia dehydrogenation are likely responsible for cobalt catalyst deactivation in the excess of oxygen atom.

Stepwise dehydrogenation of ammonia on Fcc-Co surfaces: A DFT study

International Nuclear Information System (INIS)

Ma, F.F.; Ma, S.H.; Jiao, Z.Y.; Dai, X.Q.

2017-01-01

Highlights: • On Co surfaces, oxygen atom not only strengthens ammonia-substrate interaction but also facilitates ammonia dissociation on the Co surfaces. • Pre-adsorbed O atom significantly promotes the stepwise dehydrogenation of ammonia on Co(110), giving rise to N atom strongly binding with the surface. • The dissociation of NH appears to be the rate-determining step on O-covered Co(111) and Co(100) surfaces. • The species N and NH produced in ammonia dehydrogenation are likely responsible for cobalt catalyst deactivation in the excess of oxygen atom. - Abstract: The stepwise dehydrogenation of ammonia on clean and O-covered Co surfaces have been studied by performing density functional theory (DFT) calculations. It is found that the interaction of species NH x (x = 0–3) with the Co surfaces become stronger with its further dehydrogenation, and oxygen atom not only strengthens ammonia-substrate interaction but also facilitates ammonia dissociation. Specifically, pre-adsorbed O atom significantly promotes the stepwise dehydrogenation of ammonia on Co(110), giving rise to N atom strongly binding with the surface. In contrast, the dissociation of NH appears to be the rate-determining step on O-covered Co(111) and Co(100) surfaces, due to the high energy barriers. And present results demonstrate that the species N and NH produced in ammonia dehydrogenation are likely responsible for cobalt catalyst deactivation in the excess of oxygen atom.

Thermomechanical analyses of phenolic foam reinforced with glass fiber mat

International Nuclear Information System (INIS)

Zhou, Jintang; Yao, Zhengjun; Chen, Yongxin; Wei, Dongbo; Wu, Yibing

2013-01-01

Highlights: • Over 10% glass fiber was used to reinforce phenolic foam in the shape of glass fiber mat. • Nucleating agents were used together with glass fiber mat and improved tensile strength of phenolic foam by 215.6%. • Nucleating agents lead to a smaller bubble size of phenolic foam. • The glass transition temperature of phenolic foam remained unchanged during the reinforcement. - Abstract: In this paper, thermomechanical analysis (TMA) and dynamic mechanical analysis were employed to study the properties of phenolic foam reinforced with glass fiber mat. Unreinforced phenolic foam was taken as the control sample. Mechanical tests and scanning electron microscopy were performed to confirm the results of TMA. The results show that glass fiber mat reinforcement improves the mechanical performance of phenolic foam, and nucleating agents improve it further. Phenolic foam reinforced with glass fiber mat has a smaller thermal expansion coefficient compared with unreinforced foam. The storage modulus of the reinforced phenolic foam is also higher than that in unreinforced foam, whereas the loss modulus of the former is lower than that of the latter. The glass transition temperature of the phenolic foam matrix remains unchanged during the reinforcement

Anaerobic ammonia removal in presence of organic matter: A novel route

International Nuclear Information System (INIS)

Sabumon, P.C.

2007-01-01

This study describes the feasibility of anaerobic ammonia removal process in presence of organic matter. Different sources of biomass collected from diverse eco-systems containing ammonia and organic matter (OM) were screened for potential anaerobic ammonia removal. Sequential batch studies confirmed the possibility of anaerobic ammonia removal in presence of OM, but ammonia was oxidized anoxically to nitrate (at oxidation reduction potential; ORP -248 ± 25 mV) by an unknown mechanism unlike in the reported anammox process. The oxygen required for oxidation of ammonia might have been generated through catalase enzymatic activity of facultative anaerobes in mixed culture. The oxygen generation possibility by catalase enzyme route was demonstrated. Among the inorganic electron acceptors (NO 2 - , NO 3 - and SO 4 2- ) studied, NO 2 - was found to be most effective in total nitrogen removal. Denitrification by the developed culture was much effective and faster compared to ammonia oxidation. The results of this study show that anaerobic ammonia removal is feasible in presence of OM. The novel nitrogen removal route is hypothesized as enzymatic anoxic oxidation of NH 4 + to NO 3 - , followed by denitrification via autotrophic and/or heterotrophic routes. The results of batch study were confirmed in continuous reactor operation

On the effect of aqueous ammonia soaking pretreatment on batch and continuous anaerobic digestion of digested swine manure fibers

OpenAIRE

Mirtsou Xanthopoulou, Chrysoula; Jurado, Esperanza; Skiadas, Ioannis; Gavala, Hariklia N.

2012-01-01

The continuously increasing demand for renewable energy sources renders anaerobic digestion to one of the most promising technologies for renewable energy production. Due to the animal production intensification, manure is being used as the primary feedstock for most of the biogas plants. Thus, their economical profitable operation relies on increasing the methane yield from manure, and especially of its solid fraction which is not so easily degradable. Aqueous Ammonia Soaking (AAS) has been ...

On the stability of the disordered molecular alloy phase of ammonia hemihydrate

International Nuclear Information System (INIS)

Wilson, C. W.; Bull, C. L.; Stinton, G. W.; Amos, D. M.; Donnelly, M.-E.; Loveday, J. S.

2015-01-01

The disordered-molecular-alloy phase (DMA) of ammonia hydrates [J. S. Loveday and R. J. Nelmes, Phys. Rev. Lett. 83, 4329 (1999)] is unique in that it has substitutional disorder of ammonia and water over the molecular sites of a body centred cubic lattice. Whilst this structure has been observed in ammonia di- and mono-hydrate compositions, it has not been conclusively observed in the ammonia hemihydrate system. This work presents investigations of the structural behaviour of ammonia hemihydrate as a function of P and T. The indications of earlier studies [Ma et al. RSC Adv. 2, 4290 (2012)] that the DMA structure could be produced by compression of ammonia hemihydrate above 20 GPa at ambient temperature are confirmed. In addition, the DMA structure was found to form reversibly both from the melt, and on warming of ammonia hemihydrate phase-II, in the pressure range between 4 and 8 GPa. The route used to make the DMA structure from ammonia mono- and di-hydrates—compression at 170 K to 6 GPa followed by warming to ambient temperature—was found not to produce the DMA structure for ammonia hemihydrate. These results provide the first strong evidence that DMA is a thermodynamically stable form. A high-pressure phase diagram for ammonia hemihydrate is proposed which has importance for planetary modelling

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

46 CFR 111.105-32 - Bulk liquefied flammable gas and ammonia carriers.

Science.gov (United States)

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Bulk liquefied flammable gas and ammonia carriers. 111... gas and ammonia carriers. (a) Each vessel that carries bulk liquefied flammable gases or ammonia as a.... (2) The term “gas-dangerous” does not include the weather deck of an ammonia carrier. (c) Each...

ISS Ammonia Leak Detection Through X-Ray Fluorescence

Science.gov (United States)

Camp, Jordan; Barthelmy, Scott; Skinner, Gerry

2013-01-01

Ammonia leaks are a significant concern for the International Space Station (ISS). The ISS has external transport lines that direct liquid ammonia to radiator panels where the ammonia is cooled and then brought back to thermal control units. These transport lines and radiator panels are subject to stress from micrometeorites and temperature variations, and have developed small leaks. The ISS can accommodate these leaks at their present rate, but if the rate increased by a factor of ten, it could potentially deplete the ammonia supply and impact the proper functioning of the ISS thermal control system, causing a serious safety risk. A proposed ISS astrophysics instrument, the Lobster X-Ray Monitor, can be used to detect and localize ISS ammonia leaks. Based on the optical design of the eye of its namesake crustacean, the Lobster detector gives simultaneously large field of view and good position resolution. The leak detection principle is that the nitrogen in the leaking ammonia will be ionized by X-rays from the Sun, and then emit its own characteristic Xray signal. The Lobster instrument, nominally facing zenith for its astrophysics observations, can be periodically pointed towards the ISS radiator panels and some sections of the transport lines to detect and localize the characteristic X-rays from the ammonia leaks. Another possibility is to use the ISS robot arm to grab the Lobster instrument and scan it across the transport lines and radiator panels. In this case the leak detection can be made more sensitive by including a focused 100-microampere electron beam to stimulate X-ray emission from the leaking nitrogen. Laboratory studies have shown that either approach can be used to locate ammonia leaks at the level of 0.1 kg/day, a threshold rate of concern for the ISS. The Lobster instrument uses two main components: (1) a microchannel plate optic (also known as a Lobster optic) that focuses the X-rays and directs them to the focal plane, and (2) a CCD (charge

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

Synthesis, characterization and thermal expansion studies on thorium-praseodymium mixed oxide solid solutions

International Nuclear Information System (INIS)

Panneerselvam, G.; Antony, M.P.; Srinivasan, T.G.; Vasudeva Rao, P.R.

2010-01-01

Full text: Thorium-praseodymium mixed oxide solid solutions containing 15, 25, 40 and 55 mole percent of praseodymia were synthesized by mixing the solutions of thorium nitrate in water and praseodymium oxide (Pr 6 O 11 ) in conc. HNO 3 . Subsequently, their hydroxides were co-precipitated by the addition of aqueous ammonia. Further the precipitate was dried at 50 deg C, calcined at 600 deg C for 4 hours and sintered at 1200 deg C for 6 h in air. X-ray diffraction measurements were performed for phase identification and lattice parameter derivation. Single-phase fluorite structure was observed for all the compositions. Bulk and theoretical densities of solid solutions were also determined by immersion and X-ray techniques. Thermal expansion coefficients and percentage linear thermal expansion of the solid solutions were determined using high temperature X-ray diffraction technique in the temperature range 300 to 1700 K for the first time. The room temperature lattice constants estimated for above compositions are 0.5578, 0.5565, 0.5545 and 0.5526 nm, respectively. The mean linear thermal expansion coefficients for the solid solutions are 15.48 x 10 -6 K -1 , 18.35 x 10 -6 K -1 , 22.65 x 10 -6 K -1 and 26.95 x 10 -6 K -1 , respectively. The percentage linear thermal expansions in this temperature range are 1.68, 1.89, 2.21 and 2.51 respectively. It is seen that the solid solutions are stable up to 1700 K. It is also seen that the effect and nature of the dopant are the important parameters influencing the thermal expansion of the ThO 2 . The lattice parameter of the solid solutions exhibited a decreasing trend with respect to praseodymia addition. The percentage linear thermal expansion of the solid solutions increases steadily with increasing temperature

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

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.

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.

Anaerobic digestion of swine manure: Inhibition by ammonia

DEFF Research Database (Denmark)

Hansen, Kaare Hvid; Angelidaki, Irini; Ahring, Birgitte Kiær

1998-01-01

A stable anaerobic degradation of swine manure with ammonia concentration of 6 g-N/litre was obtained in continuously stirred tank reactors with a hydraulic retention time of 15 days, at Four different temperatures. Methane yields of 188, 141, 67 and 22 ml-CH4/g-VS were obtained at 37, 45, 55...... and 60 degrees C, respectively. The yields were significantly lower than the potential biogas yield of the swine manure used (300 ml-CH4/g-VS). A free ammonia concentration of 1.1 g-N/litre or more was found to cause inhibition in batch cultures at pH 8.0 (reactor pH), and higher free ammonia...... concentrations resulted in a decreased apparent specific growth rate. Batch experiments with various mixtures of swine and cattle manure showed that the biogas process was inhibited when the swine-to-cattle manure ratio was higher than 25:75, corresponding to a free ammonia concentration of approximately 1.1 g...

Serial ammonia measurement in patients poisoned with glufosinate ammonium herbicide.

Science.gov (United States)

Moon, J M; Chun, B J

2016-05-01

This study investigated whether ammonia concentrations can predict delayed neurotoxicity development and neurotoxicity latency in glufosinate ammonium (GLA) herbicide-poisoned patients presenting with an alert mental state and stable hemodynamics. This retrospective observational case study included 26 patients divided into 2 groups: neurotoxicity during hospitalization (complicated group) and without neurotoxicity (noncomplicated group). Thirteen patients (50.0%) experienced neurotoxicity at 16 h post-ingestion. Although ammonia concentrations at presentation did not differ significantly between the two groups, the ammonia level in the complicated group increased significantly at the next measurement and remained significantly higher than that in the noncomplicated group until 48 h after ingestion. The peak ammonia concentration before neurotoxicity development was an independent predictor of neurotoxicity (odds ratio: 1.047, 95% confidence interval: 1.010-1.087, p value = 0.014), and the optimal cutoff value of peak ammonia concentration for predicting neurotoxicity was 101.5 μg/dL. The rate of ammonia increase was not associated with the time latency from ingestion to neurotoxicity development. This study showed that serial ammonia measurements in GLA-poisoned patients may identify those who are at high risk of developing neurotoxicity. However, as this study enrolled few patients, further qualified trials are required to confirm our results and to reveal the etiology of hyperammonemia and its causality in neurotoxicity. © The Author(s) 2015.

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

Effects of gaseous ammonia direct injection on performance characteristics of a spark-ignition engine

International Nuclear Information System (INIS)

Ryu, Kyunghyun; Zacharakis-Jutz, George E.; Kong, Song-Charng

2014-01-01

Highlights: • This is the very first study in utilizing direct injection of gaseous ammonia in an SI engine. • Engine combustion using direct injection of gaseous ammonia is proven feasible. • Energy efficiency using ammonia is comparable to that using gasoline. • CO emissions are decreased but emissions of NOx and HC are increased when ammonia is used. - Abstract: The effects of direct injection of gaseous ammonia on the combustion characteristics and exhaust emissions of a spark-ignition engine were investigated. Port-injection gasoline was used to enhance the burning of ammonia that was directly injected into the engine cylinder. Appropriate direct injection strategies were developed to allow ammonia to be used in spark-ignition engines without sacrifice of volumetric efficiency. Experimental results show that with gasoline providing the baseline power of 0.6 kW, total engine power could increase to 2.7 kW when the injection timing of ammonia was advanced to 370 BTDC with injection duration of 22 ms. Engine performance with use of gasoline–ammonia was compared to that with gasoline alone. For operations using gasoline–ammonia, with baseline power from gasoline at 0.6 kW the appropriate ammonia injection timing was found to range from 320 to 370 BTDC for producing 1.5–2.7 kW. The peak pressures were slightly lower than those using gasoline alone because of the lower flame of ammonia, resulting in reduction of cylinder pressure. The brake specific energy consumption (BSEC) with gasoline–ammonia was very similar to that with gasoline alone. Ammonia direct injection caused slight reductions of BSCO for all the loads studied but significantly increased BSHC because of the reduced combustion temperature of ammonia combustion. The use of ammonia resulted in increased NOx emissions because of formation of fuel NOx. Ammonia slip was also detected in the engine exhaust because of incomplete combustion

Dynamic Model of an Ammonia Synthesis Reactor Based on Open Information

OpenAIRE

Jinasena, Asanthi; Lie, Bernt; Glemmestad, Bjørn

2016-01-01

Ammonia is a widely used chemical, hence the ammonia manufacturing process has become a standard case study in the scientific community. In the field of mathematical modeling of the dynamics of ammonia synthesis reactors, there is a lack of complete and well documented models. Therefore, the main aim of this work is to develop a complete and well documented mathematical model for observing the dynamic behavior of an industrial ammonia synthesis reactor system. The model is complete enough to ...

Coupling Solid Oxide Electrolyser (SOE) and ammonia production plant

International Nuclear Information System (INIS)

Cinti, Giovanni; Frattini, Domenico; Jannelli, Elio; Desideri, Umberto; Bidini, Gianni

2017-01-01

Highlights: • An innovative NH 3 production plant was designed. • CO 2 emissions and energy consumption are studied in three different designs. • High temperature electrolysis allows to achieve high efficiency and heat recovery. • The coupling permits storage of electricity into a liquid carbon free chemical. - Abstract: Ammonia is one of the most produced chemicals worldwide and is currently synthesized using nitrogen separated from air and hydrogen from natural gas reforming with consequent high consumption of fossil fuel and high emission of CO 2 . A renewable path for ammonia production is desirable considering the potential development of ammonia as energy carrier. This study reports design and analysis of an innovative system for the production of green ammonia using electricity from renewable energy sources. This concept couples Solid Oxide Electrolysis (SOE), for the production of hydrogen, with an improved Haber Bosch Reactor (HBR), for ammonia synthesis. An air separator is also introduced to supply pure nitrogen. SOE operates with extremely high efficiency recovering high temperature heat from the Haber-Bosch reactor. Aspen was used to develop a model to study the performance of the plant. Both the SOE and the HBR operate at 650 °C. Ammonia production with zero emission of CO 2 can be obtained with a reduction of 40% of power input compared to equivalent plants.

THEORETICAL EVALUATION OF NONLINEAR EFFECTS ON OPTICAL WDM NETWORKS WITH VARIOUS FIBER TYPES

Directory of Open Access Journals (Sweden)

YASIN M. KARFAA

2010-09-01

Full Text Available A theoretical study is carried out to evaluate the performance of an opticalwavelength division multiplexing (WDM network transmission system in the presenceof crosstalk due to optical fiber nonlinearities. The most significant nonlinear effects inthe optical fiber which are Cross-Phase Modulation (XPM, Four-Wave Mixing (FWM,and Stimulated Raman Scattering (SRS are investigated. Four types of optical fiber areincluded in the analysis; these are: single-mode fiber (SMF, dispersion compensationfiber (DCF, non-zero dispersion fiber (NZDF, and non-zero dispersion shifted fiber(NZDSF. The results represent the standard deviation of nonlinearity induced crosstalknoise power due to FWM and SRS, XPM power penalty for SMF, DCF, NZDF, andNZDSF types of fiber, besides the Bit Error Rate (BER for the three nonlinear effectsusing standard fiber type (SMF. It is concluded that three significant fiber nonlinearitiesare making huge limitations against increasing the launched power which is desired,otherwise, lower values of launched power limit network expansion including length,distance, covered areas, and number of users accessing the WDM network, unlesssuitable precautions are taken to neutralize the nonlinear effects. Besides, various fibertypes are not behaving similarly towards network parameters.

Orion Ammonia Boiler System Preflight Test Preparations

Science.gov (United States)

Levitt, Julia L.

2017-01-01

The Environmental Controls and Life Support Systems (ECLSS) branch at Kennedy Space Center (KSC) is currently undergoing preparations for ground testing of the Orion Multi-Purpose Crew Vehicle (MPCV) to prepare its subsystems for EM-1 (Exploration Mission-1). EM-1, Orions second unmanned flight, is a three-week long lunar mission during which the vehicle will complete a 6-day retrograde lunar orbit before returning to Earth. This paper focuses on the work done during the authors 16-week internship with the Mechanical Engineering Branch of KSCs Engineering Directorate. The authors project involved assisting with the preparations for testing the Orion MPCVs ammonia boiler system. The purpose of the ammonia boiler system is to keep the spacecraft sufficiently cool during the reentry portion of its mission, from service module (SM) separation to post-landing. This system is critical for keeping both the spacecraft (avionics and electronics) and crew alive during reentry, thus a successful test of the system is essential to the success of EM-1. XXXX The author was able to draft a detailed outline of the procedure for the ammonia system functional test. More work will need to be done on the vehicle power-up and power-down portions of the procedure, but the ammonia system testing portion of the procedure is thorough and includes vehicle test configurations, vehicle commands, and GSE. The author was able to compile a substantial list of questions regarding the ammonia system functional test with the help of her mentors. A significant number of these questions were answered in the teleconferences with Lockheed Martin.

On-board ammonia generation and exhaust after treatment system using same

Science.gov (United States)

Driscoll, Josh; Robel, Wade J.; Brown, Cory A.; Urven, Jr., Roger L.

2010-03-30

Often NOx selective catalysts that use ammonia to reduce NOx within exhaust to a harmless gas require on-board storage of ammonia which can be hazardous and inconvenient. In order to generate ammonia in exhaust, the present disclosure increases a NOx concentration in exhaust from at least one combustion chamber, at least in part, by injecting fuel in a predetermined increased NOx generation sequence that includes a first injection during non-auto ignition conditions and a second injection during auto ignition conditions. At least a portion of the NOx is converted to ammonia by passing at least a portion of the exhaust with the increased NOx concentration over an ammonia-producing catalyst.

Power cycles with ammonia-water mixtures as working fluid

Energy Technology Data Exchange (ETDEWEB)

Thorin, Eva

2000-05-01

It is of great interest to improve the efficiency of power generating processes, i.e. to convert more of the energy in the heat source to power. This is favorable from an environmental point of view and can also be an economic advantage. To use an ammonia-water mixture instead of water as working fluid is a possible way to improve the efficiency of steam turbine processes. This thesis includes studies of power cycles with ammonia-water mixtures as working fluid utilizing different kinds of heat sources for power and heat generation. The thermophysical properties of the mixture are also studied. They play an important role in the calculations of the process performance and for the design of its components, such as heat exchangers. The studies concern thermodynamic simulations of processes in applications suitable for Swedish conditions. Available correlations for the thermophysical properties are compared and their influence on simulations and heat exchanger area predictions is investigated. Measurements of ammonia-water mixture viscosities using a vibrating wire viscometer are also described. The studies performed show that power cycles with ammonia-water mixtures as the working fluid are well suited for utilization of waste heat from industry and from gas engines. The ammonia-water power cycles can give up to 32 % more power in the industrial waste heat application and up to 54 % more power in the gas engine bottoming cycle application compared to a conventional Rankine steam cycle. However, ammonia-water power cycles in small direct-fired biomass-fueled cogeneration plants do not show better performance than a conventional Rankine steam cycle. When different correlations for the thermodynamic properties are used in simulations of a simple ammonia-water power cycle the difference in efficiency is not larger than 4 %, corresponding to about 1.3 percentage points. The differences in saturation properties between the correlations are, however, considerable at high

Effect of ammonia on the anaerobic hydrolysis of cellulose and tributyrin

NARCIS (Netherlands)

Vasconcelos Fernandes, T.; Keesman, K.J.; Zeeman, G.; Lier, van J.B.

2012-01-01

Ammonia nitrogen is one of the most common inhibitors in the anaerobic digestion of complex wastes containing high concentrations of ammonia like animal manures, blackwater and waste oil from gastronomy. The inhibiting effect of ammonia on methanogenesis has been well established. In contrast, the

Abatement of ammonia emissions from digested manure using gas-permeable membranes

Science.gov (United States)

A new strategy to avoid ammonia emissions from anaerobically digested swine manure was tested using the gas-permeable membrane process. Evaluation of the efficiency of ammonia recovery from digestate as well as mitigation of ammonia emissions to the atmosphere were carried out. Digestate was colle...

The Full-Scale Implementation of an Innovative Biological Ammonia Treatment Process

Science.gov (United States)

Across the United States, high levels of ammonia in drinking water sources can be found, including small communities like Palo, Iowa (approximate population of 1,026). Although ammonia in water does not pose a direct health concern, ammonia nitrification can cause a number of iss...

Decreased STAT3 Phosphorylation Mediates Cell Swelling in Ammonia-Treated Astrocyte Cultures

Directory of Open Access Journals (Sweden)

Arumugam R. Jayakumar

2016-12-01

Full Text Available Brain edema, due largely to astrocyte swelling, and the subsequent increase in intracranial pressure and brain herniation, are major complications of acute liver failure (ALF. Elevated level of brain ammonia has been strongly implicated in the development of astrocyte swelling associated with ALF. The means by which ammonia brings about astrocyte swelling, however, is incompletely understood. Recently, oxidative/nitrosative stress and associated signaling events, including activation of mitogen-activated protein kinases (MAPKs, as well as activation of the transcription factor, nuclear factor-kappaB (NF-κB, have been implicated in the mechanism of ammonia-induced astrocyte swelling. Since these signaling events are known to be regulated by the transcription factor, signal transducer and activator of transcription 3 (STAT3, we examined the state of STAT3 activation in ammonia-treated cultured astrocytes, and determined whether altered STAT3 activation and/or protein expression contribute to the ammonia-induced astrocyte swelling. STAT3 was found to be dephosphorylated (inactivated at Tyrosine705 in ammonia-treated cultured astrocytes. Total STAT3 protein level was also reduced in ammonia-treated astrocytes. We also found a significant increase in protein tyrosine phosphatase receptor type-1 (PTPRT-1 protein expression in ammonia-treated cultured astrocytes, and that inhibition of PTPRT-1 enhanced the phosphorylation of STAT3 after ammonia treatment. Additionally, exposure of cultured astrocytes to inhibitors of protein tyrosine phosphatases diminished the ammonia-induced cell swelling, while cultured astrocytes over-expressing STAT3 showed a reduction in the astrocyte swelling induced by ammonia. Collectively, these studies strongly suggest that inactivation of STAT3 represents a critical event in the mechanism of the astrocyte swelling associated with acute liver failure.

Ammonia Levels and Hepatic Encephalopathy in Patients with Known Chronic Liver Disease.

Science.gov (United States)

Ninan, Jacob; Feldman, Leonard

2017-08-01

Ammonia is predominantly generated in the gut by intestinal bacteria and enzymes and detoxified primarily in the liver. Since the 1930s, ammonia has been identified as the principal culprit in hepatic encephalopathy (HE). Many physicians utilize serum ammonia to diagnose, assess severity, and determine the resolution of HE in patients with chronic liver disease (CLD) despite research showing that ammonia levels are unhelpful in all of these clinical circumstances. HE in patients with CLD is a clinical diagnosis of exclusion that should not be based on ammonia levels. © 2017 Society of Hospital Medicine.

Visible bands of ammonia: band strengths, curves of growth, and the spatial distribution of ammonia on Jupiter

International Nuclear Information System (INIS)

Lutz, B.L.; Owen, T.

1980-01-01

We report room-temperature laboratory studies of the 5520 A (6ν 1 ) and 6475 A (5ν 1 ) bands of self-broadened ammonia at column densities ranging from 1.7--435.7 meter-amagats (m-am). Detailed equivalent-width measurements at 24 different pressure-pathlength combinations corresponding to four pressures between 44 and 689 torr and pathlengths between 32 and 512 m are used to determin curves of growth and integrated band strengths. The band strengths for the 6ν 1 and 5ν 1 overtones are 5520 A: S=0.096 +- 0.005 cm -1 (m-am) -1 and 6475 A: S=0.63 +- 0.03 cm -1 (m-am) -1 , respectively.Using these band strengths and curves of growth, we analyze new spatially resolved spectra of Jupiter showing a nonhomogeneous distribution of ammonia in the Jovian atmosphere. The observed variations in the CH 4 /NH 3 mixing ratio are interpreted as evidence of altitude-dependent depletion of ammonia in the atmosphere

Ammonia-water exchange front end process for ammonia-hydrogen heavy water plants (Preprint No. PD-1)

International Nuclear Information System (INIS)

Sadhukhan, H.K.; Varadarajan, T.G.; Nair, N.K.; Das, S.K.; Nath, G.K.

1989-04-01

The ammonia-hydrogen exchange process, which utilizes the deutrium exchange between liquid ammonia and gaseous hydrogen is a parasitic process and the heavy water plants (HWP) based on this process has to be linked with the fertilizer plant (FP) for its enormous requirements of hydrogen (synthesis gas, N 2 +3H 2 ). This dependence of HWP on FP gives rise to certain constraints which are listed. These deficiencies of the ammonia-hydrogen process can be overcome to a great extent by delinking the HWP from FP by incorporating NH 3 -H 2 O exchange as the front end step. In addition to the elimination of the above limitations, by employing water as the ultimate feed for the HWP, the plant capacity can be increased substantially and this would go a long way in achieving economies of the large capacity plants. A schematic diagram of this integrated plant is given. Some of the results of developmental efforts and feasibility studies of this NH 3 -H 2 O exchange are briefly reviewed. (author). 4 figs

Enrichment of high ammonia tolerant methanogenic culture

DEFF Research Database (Denmark)

Fotidis, Ioannis; Karakashev, Dimitar Borisov; Proietti, Nicolas

Ammonia is the major toxicant in full scale anaerobic digesters of animal wastes which are rich in proteins and/or urea, such as pig or poultry wastes. Ammonia inhibition decreases methane production rates, increases volatile fatty acids concentration and leads to economic losses for the biogas...... was derived from a full scale biogas reactor (Hashøj, Denmark), fed with 75% animal manure and 25% food industries organic waste. Basal anaerobic medium was used for the enrichment along with sodium acetate (1 g HAc L-1) as a carbon source. Fluorescence insitu hybridization (FISH) was used to determine...... exclusively to strict aceticlastic methanogens. Results obtained in this study, demonstrated for the first time that strictly aceticlastic methanogens, derived from an enriched culture, can efficiently produce methane under high ammonia levels....

Phase 2 comparison of a novel ammonia scavenging agent with sodium phenylbutyrate in patients with urea cycle disorders: safety, pharmacokinetics and ammonia control.

Science.gov (United States)

Lee, Brendan; Rhead, William; Diaz, George A; Scharschmidt, Bruce F; Mian, Asad; Shchelochkov, Oleg; Marier, J F; Beliveau, Martin; Mauney, Joseph; Dickinson, Klara; Martinez, Antonia; Gargosky, Sharron; Mokhtarani, Masoud; Berry, Susan A

2010-07-01

Glycerol phenylbutyrate (glyceryl tri (4-phenylbutyrate)) (GPB) is being studied as an alternative to sodium phenylbutyrate (NaPBA) for the treatment of urea cycle disorders (UCDs). This phase 2 study explored the hypothesis that GPB offers similar safety and ammonia control as NaPBA, which is currently approved as adjunctive therapy in the chronic management of UCDs, and examined correlates of 24-h blood ammonia. An open-label, fixed sequence switch-over study was conducted in adult UCD patients taking maintenance NaPBA. Blood ammonia and blood and urine metabolites were compared after 7 days (steady state) of TID dosing on either drug, both dosed to deliver the same amount of phenylbutyric acid (PBA). Ten subjects completed the study. Adverse events were comparable for the two drugs; 2 subjects experienced hyperammonemic events on NaPBA while none occurred on GPB. Ammonia values on GPB were approximately 30% lower than on NaPBA (time-normalized AUC=26.2 vs. 38.4 micromol/L; Cmax=56.3 vs. 79.1 micromol/L; not statistically significant), and GPB achieved non-inferiority to NaPBA with respect to ammonia (time-normalized AUC) by post hoc analysis. Systemic exposure (AUC(0-24)) to PBA on GPB was 27% lower than on NaPBA (540 vs. 739 microgh/mL), whereas exposure to phenylacetic acid (PAA) (575 vs. 596 microg h/mL) and phenylacetylglutamine (PAGN) (1098 vs. 1133 microg h/mL) were similar. Urinary PAGN excretion accounted for approximately 54% of PBA administered for both NaPBA and GPB; other metabolites accounted for <1%. Intact GPB was generally undetectable in blood and urine. Blood ammonia correlated strongly and inversely with urinary PAGN (r=-0.82; p<0.0001) but weakly or not at all with blood metabolite levels. Safety and ammonia control with GPB appear at least equal to NaPBA. Urinary PAGN, which is stoichiometrically related to nitrogen scavenging, may be a useful biomarker for both dose selection and adjustment for optimal control of venous ammonia. Copyright

Expansive soil stabilization with coir waste and lime for flexible pavement subgrade

Science.gov (United States)

Narendra Goud, G.; Hyma, A.; Shiva Chandra, V.; Sandhya Rani, R.

2018-03-01

Expansive soil properties can be improved by various methods to make it suitable for construction of flexible pavement. The coir pith is the by-product (bio-waste) generated from coir industry during extraction of coir fiber from coconut husk. Openly disposed coir pith can make the surrounding areas unhygienic. This bio-waste can be one of the potential materials to stabilize the expansive soils. In the present study coir pith and lime are used as stabilizers. Different combinations of coir pith contents (1%, 2% and 3%) and lime contents (2%, 3% and 4%)are used to study the behavior of expansive soil. Unconfined compressive strength (UCS) of unstabilized and stabilized soils was determined. Optimum content of coir pith and lime are determined based on UCS of the soil. California bearing ratio of soil determined at optimum contents of coir pith and lime. Flexible pavement layer compositions for two levels of traffic using stabilized soil subgrade.

Ammonia loss, ammonium and nitrate accumulation from mixing ...

African Journals Online (AJOL)

Ammonia loss from urea significantly hinders efficient use of urea in agriculture. In order to reduce ammonia loss and, at the same time, improve beneficial accumulation of soil exchangeable ammonium and nitrate for efficient utilization by plants, this laboratory study was conducted to determine the effect of mixing urea with ...

Valorization of guayule as a feedstock for lignocellulosic biorefineries using ammonia fiber expansion (AFEX) pretreatment

Science.gov (United States)

Natural rubber latex extraction from guayule leaves behind greater than 80% (by weight) of agricultural residue as a feedstock suitable for conversion to biofuels via a thermochemical or biochemical route. Untreated guayule shrub and bagasse (after latex extraction) has shown to be very recalcitrant...

Stabilization of ammonia-rich hydrate inside icy planets.

Science.gov (United States)

Naden Robinson, Victor; Wang, Yanchao; Ma, Yanming; Hermann, Andreas

2017-08-22

The interior structure of the giant ice planets Uranus and Neptune, but also of newly discovered exoplanets, is loosely constrained, because limited observational data can be satisfied with various interior models. Although it is known that their mantles comprise large amounts of water, ammonia, and methane ices, it is unclear how these organize themselves within the planets-as homogeneous mixtures, with continuous concentration gradients, or as well-separated layers of specific composition. While individual ices have been studied in great detail under pressure, the properties of their mixtures are much less explored. We show here, using first-principles calculations, that the 2:1 ammonia hydrate, (H 2 O)(NH 3 ) 2 , is stabilized at icy planet mantle conditions due to a remarkable structural evolution. Above 65 GPa, we predict it will transform from a hydrogen-bonded molecular solid into a fully ionic phase O 2- ([Formula: see text]) 2 , where all water molecules are completely deprotonated, an unexpected bonding phenomenon not seen before. Ammonia hemihydrate is stable in a sequence of ionic phases up to 500 GPa, pressures found deep within Neptune-like planets, and thus at higher pressures than any other ammonia-water mixture. This suggests it precipitates out of any ammonia-water mixture at sufficiently high pressures and thus forms an important component of icy planets.

Exhaust purification with on-board ammonia production

Science.gov (United States)

Robel, Wade J [Peoria, IL; Driscoll, James Joshua [Dunlap, IL; Coleman, Gerald N [Peterborough, GB

2008-05-13

A system of ammonia production for a selective catalytic reduction system is provided. The system includes producing an exhaust gas stream within a cylinder group, wherein the first exhaust gas stream includes NOx. The exhaust gas stream may be supplied to an exhaust passage and cooled to a predetermined temperature range, and at least a portion of the NOx within the exhaust gas stream may be converted into ammonia.

Arterial ammonia levels in the management of fulminant liver failure

Directory of Open Access Journals (Sweden)

Curry S

2011-06-01

Full Text Available Previous studies have suggested that an arterial ammonia level greater than 150 mmol/L is highly sensitive for predicting subsequent development of cerebral edema in patients with fulminant liver failure. We performed a prospective cohort study to confirm this relationship. We enrolled 22 consecutive patients who presented to our transplant hepatology service with grade 3-4 encephalopathy associated with fulminant liver failure. All patients underwent placement of an intraparenchymal ICP monitor, and every 12 hourly arterial ammonia levels. The prevalence of intracranial hypertension (IHTN in our population was 95% (21/22 patients, with 82 discrete episodes recorded. The sensitivity of arterial ammonia levels to predict the onset of IHTN was 62% (95% CI: 40.8 to 79.3 at a cut point of 150 mmol/L. Arterial ammonia levels preceding the first intracranial hypertension event were less than 150 mmol/L in 8 of 21 patients (39%. Fifty nine of 82 episodes of IHTN (73% occurred when arterial ammonia levels were less than 150 mmol/L. We conclude that the arterial ammonia level is not useful in making decisions regarding management related to cerebral edema in patients with fulminant liver failure. In fact, since almost all our study patients with grade III or IV encephalopathy secondary to fulminant liver failure went on to develop intracranial hypertension, our study supports the contention that all such patients might benefit from ICP monitoring regardless of arterial ammonia levels.

Measurement of spatial refractive index distributions of fusion spliced optical fibers by digital holographic microtomography

Science.gov (United States)

Pan, Feng; Deng, Yating; Ma, Xichao; Xiao, Wen

2017-11-01

Digital holographic microtomography is improved and applied to the measurements of three-dimensional refractive index distributions of fusion spliced optical fibers. Tomographic images are reconstructed from full-angle phase projection images obtained with a setup-rotation approach, in which the laser source, the optical system and the image sensor are arranged on an optical breadboard and synchronously rotated around the fixed object. For retrieving high-quality tomographic images, a numerical method is proposed to compensate the unwanted movements of the object in the lateral, axial and vertical directions during rotation. The compensation is implemented on the two-dimensional phase images instead of the sinogram. The experimental results exhibit distinctly the internal structures of fusion splices between a single-mode fiber and other fibers, including a multi-mode fiber, a panda polarization maintaining fiber, a bow-tie polarization maintaining fiber and a photonic crystal fiber. In particular, the internal structure distortion in the fusion areas can be intuitively observed, such as the expansion of the stress zones of polarization maintaining fibers, the collapse of the air holes of photonic crystal fibers, etc.

Effects of high-speed homogenization and high-pressure homogenization on structure of tomato residue fibers.

Science.gov (United States)

Hua, Xiao; Xu, Shanan; Wang, Mingming; Chen, Ying; Yang, Hui; Yang, Ruijin

2017-10-01

Tomato residue fibers obtained after derosination and deproteinization were processed by high-speed homogenization (HSH) and high-pressure homogenization (HPH), and their effects on fiber structure was investigated, respectively. Characterizations including particle size distribution, SEM, TEM and XRD were performed. HSH could break raw fibers to small particles of around 60μm, while HPH could reshape fibers to build network structure. Microfibrils were released and their nanostructure consisting of elementary fibrils was observed by TEM. XRD patterns indicated both HSH and HPH could hardly alter the nanostructure of the fibers. Physicochemical properties including expansibility, WHC and OHC were determined. Both HSH and HPH could increase the soluble fiber content by about 8%, but HSH-HPH combined processing did not show better result. Acid (4mol/L HCl) was used in replacement of water medium and the acidic degradation of fibers could be promoted by high speed shearing or high pressure processing. Copyright © 2017 Elsevier Ltd. All rights reserved.

Mesoporous coaxial titanium nitride-vanadium nitride fibers of core-shell structures for high-performance supercapacitors.

Science.gov (United States)

Zhou, Xinhong; Shang, Chaoqun; Gu, Lin; Dong, Shanmu; Chen, Xiao; Han, Pengxian; Li, Lanfeng; Yao, Jianhua; Liu, Zhihong; Xu, Hongxia; Zhu, Yuwei; Cui, Guanglei

2011-08-01

In this study, titanium nitride-vanadium nitride fibers of core-shell structures were prepared by the coaxial electrospinning, and subsequently annealed in the ammonia for supercapacitor applications. These core-shell (TiN-VN) fibers incorporated mesoporous structure into high electronic conducting transition nitride hybrids, which combined higher specific capacitance of VN and better rate capability of TiN. These hybrids exhibited higher specific capacitance (2 mV s(-1), 247.5 F g(-1)) and better rate capability (50 mV s(-1), 160.8 F g(-1)), which promise a good candidate for high-performance supercapacitors. It was also revealed by electrochemical impedance spectroscopy (EIS) and X-ray photoelectron spectroscopy (XPS) characterization that the minor capacitance fade originated from the surface oxidation of VN and TiN.

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.

Effect of fiber source on cecal fermentation and nitrogen recycled through cecotrophy in rabbits.

Science.gov (United States)

García, J; Carabaño, R; Pérez-Alba, L; de Blas, J C

2000-03-01

The influence of fiber source on fiber digestion in rabbits was investigated. Six fibrous feedstuffs with wide differences in chemical composition and particle size were selected: paprika meal, olive leaves, alfalfa hay, soybean hulls, sodium hydroxide-treated barley straw, and sunflower hulls. Six diets were formulated to contain one of these ingredients as the sole source of fiber. To avoid nutrient imbalances, fiber sources were supplemented with different proportions of a fiber-free concentrate, based on soy protein isolate, wheat flour, lard, and a vitamin and mineral mix, to obtain diets containing at least 3% nitrogen and 5% starch. Daily soft feces excretion, and its NDF, and total and microbial nitrogen content were determined in 60 fattening rabbits (10 per diet). Seven days after the last cecotrophy control, the same animals were used to determine weight of stomach, cecum and their contents, and cecal fermentation traits (pH, VFA and ammonia concentrations, and buffer properties of cecal contents). Stepwise regression analysis showed a positive effect (P 1.25 mm). Degree of lignification of NDF decreased total nitrogen concentration in soft feces and cecal VFA concentration (P lignification of NDF, and base-buffering capacity of dry cecal contents (r = -.52, -.37, and -.49, respectively). From these results, we conclude that pectic constituent concentration, degree of lignification of NDF, and particle size are the variables that best characterize the influence of the source of fiber on soft feces excretion and cecal fermentation traits in rabbits.

Ammonia nitrogen removal from aqueous solution by local agricultural wastes

Science.gov (United States)

Azreen, I.; Lija, Y.; Zahrim, A. Y.

2017-06-01

Excess ammonia nitrogen in the waterways causes serious distortion to environment such as eutrophication and toxicity to aquatic organisms. Ammonia nitrogen removal from synthetic solution was investigated by using 40 local agricultural wastes as potential low cost adsorbent. Some of the adsorbent were able to remove ammonia nitrogen with adsorption capacity ranging from 0.58 mg/g to 3.58 mg/g. The highest adsorption capacity was recorded by Langsat peels with 3.58 mg/g followed by Jackfruit seeds and Moringa peels with 3.37 mg/g and 2.64 mg/g respectively. This experimental results show that the agricultural wastes can be utilized as biosorbent for ammonia nitrogen removal. The effect of initial ammonia nitrogen concentration, pH and stirring rate on the adsorption process were studied in batch experiment. The adsorption capacity reached maximum value at pH 7 with initial concentration of 500 mg/L and the removal rate decreased as stirring rate was applied.

Predicting catalysis: Understanding ammonia synthesis from first-principles calculations

DEFF Research Database (Denmark)

Hellmann, A.; Baerends, E.J.; Biczysko, M.

2006-01-01

. Furthermore, our studies provide new insight into several related fields, for instance, gas-phase and electrochemical ammonia synthesis. The success of predicting the outcome of a catalytic reaction from first-principles calculations supports our point of view that, in the future, theory will be a fully......Here, we give a full account of a large collaborative effort toward an atomic-scale understanding of modern industrial ammonia production over ruthenium catalysts. We show that overall rates of ammonia production can be determined by applying various levels of theory (including transition state...... for any given point along an industrial reactor, and the kinetic results can be integrated over the catalyst bed to determine the industrial reactor yield. We find that, given the present uncertainties, the rate of ammonia production is well-determined directly from our atomic-scale calculations...

Process for producing 13N-ammonia and device therefor

International Nuclear Information System (INIS)

Tanaka, Akira; Suzuki, Hirofumi.

1997-01-01

Ethanol or hydrogen is added to purified water or distilled water for injection, they are filled into a target vessel, and proton beams are irradiated to produce 13N-ammonia in the target vessel. A target liquid containing the resultant is introduced to a heat-reaction vessel. A slight amount of weak alkali solution is added to the target liquid in the heat-reaction vessel. The reaction vessel is heated to evaporate water and 13N-ammonia, and they are transferred to a vial. In this case, nitrogen gas as a gas to be entrained is supplied. 13N-ammonia is subjected to bubbling into the distilled water for injection or physiological saline water and recovered into the vial. 13N-ammonia is thus separated and purified as an injection which is a medical labelled compound. (I.N.)

Ammonia abundances in four comets

International Nuclear Information System (INIS)

Wickoff, S.; Tegler, S.C.; Engel, L.

1991-01-01

NH2 emission band strengths were measured in four comets and the NH2 column densities were determined in order to measure the ammonia content of the comets. The mean ammonia/water abundance ratio derived for the four comets is found to be 0.13 + or - 0.06 percent, with no significant variation among the comets. The uniformity of this abundance attests to a remarkable degree of chemical homogeneity over large scales in the comet-forming region of the primordial solar nebula, and contrasts with the CO abundance variations found previously in comets. The N2 and NH3 abundances indicate a condensation temperature in the range 20-160 K, consistent with virtually all comet formation hypotheses. 64 refs

Artificial muscles made of chiral two-way shape memory polymer fibers

Science.gov (United States)

Yang, Qianxi; Fan, Jizhou; Li, Guoqiang

2016-10-01

In this work, we demonstrate the unusual improvement of the tensile actuation of hierarchically chiral structured artificial muscle made of two-way shape memory polymer (2W-SMP) fiber. Experimental results show that the chemically cross-linked poly(ethylene-co-vinyl acetate) 2W-SMP fibers possess an average negative coefficient of thermal expansion (NCTE) that is at least one order higher than that of the polyethylene fiber used previously. As expected, the increase in axial thermal contraction of the precursor fiber leads to an increase in the recovered torque ( 4.4 Nmm ) of the chiral fiber and eventually in the tensile actuation of the twisted-then-coiled artificial muscle ( 67.81 ±1.82 % ). A mechanical model based on Castigliano's second theorem is proposed, and the calculated result is consistent with the experimental result (64.17% tensile stroke). The model proves the significance of the NCTE and the recovered torque on tensile actuation of the artificial muscle and can be used as a guidance for the future design.

[An optical-fiber-sensor-based spectrophotometer for soil non-metallic nutrient determination].

Science.gov (United States)

He, Dong-xian; Hu, Juan-xiu; Lu, Shao-kun; He, Hou-yong

2012-01-01

In order to achieve rapid, convenient and efficient soil nutrient determination in soil testing and fertilizer recommendation, a portable optical-fiber-sensor-based spectrophotometer including immersed fiber sensor, flat field holographic concave grating, and diode array detector was developed for soil non-metallic nutrient determination. According to national standard of ultraviolet and visible spectrophotometer with JJG 178-2007, the wavelength accuracy and repeatability, baseline stability, transmittance accuracy and repeatability measured by the prototype instrument were satisfied with the national standard of III level; minimum spectral bandwidth, noise and excursion, and stray light were satisfied with the national standard of IV level. Significant linear relationships with slope of closing to 1 were found between the soil available nutrient contents including soil nitrate nitrogen, ammonia nitrogen, available phosphorus, available sulfur, available boron, and organic matter measured by the prototype instrument compared with that measured by two commercial single-beam-based and dual-beam-based spectrophotometers. No significant differences were revealed from the above comparison data. Therefore, the optical-fiber-sensor-based spectrophotometer can be used for rapid soil non-metallic nutrient determination with a high accuracy.

Reactor for removing ammonia

Science.gov (United States)

Luo, Weifang [Livermore, CA; Stewart, Kenneth D [Valley Springs, CA

2009-11-17

Disclosed is a device for removing trace amounts of ammonia from a stream of gas, particularly hydrogen gas, prepared by a reformation apparatus. The apparatus is used to prevent PEM "poisoning" in a fuel cell receiving the incoming hydrogen stream.

Biotreatment of ammonia and butanal containing waste gases

NARCIS (Netherlands)

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

Urea and Ammonia Metabolism and the Control of Renal Nitrogen Excretion

Science.gov (United States)

Mitch, William E.; Sands, Jeff M.

2015-01-01

Renal nitrogen metabolism primarily involves urea and ammonia metabolism, and is essential to normal health. Urea is the largest circulating pool of nitrogen, excluding nitrogen in circulating proteins, and its production changes in parallel to the degradation of dietary and endogenous proteins. In addition to serving as a way to excrete nitrogen, urea transport, mediated through specific urea transport proteins, mediates a central role in the urine concentrating mechanism. Renal ammonia excretion, although often considered only in the context of acid-base homeostasis, accounts for approximately 10% of total renal nitrogen excretion under basal conditions, but can increase substantially in a variety of clinical conditions. Because renal ammonia metabolism requires intrarenal ammoniagenesis from glutamine, changes in factors regulating renal ammonia metabolism can have important effects on glutamine in addition to nitrogen balance. This review covers aspects of protein metabolism and the control of the two major molecules involved in renal nitrogen excretion: urea and ammonia. Both urea and ammonia transport can be altered by glucocorticoids and hypokalemia, two conditions that also affect protein metabolism. Clinical conditions associated with altered urine concentrating ability or water homeostasis can result in changes in urea excretion and urea transporters. Clinical conditions associated with altered ammonia excretion can have important effects on nitrogen balance. PMID:25078422

Frozen ammonia micropellet generator for Baseball II-T

International Nuclear Information System (INIS)

Denhoy, B.S.

1975-01-01

A ''startup'' plasma at the center of the Baseball II-T magnet was studied. This startup plasma will be used as a target for high energy neutral beams to achieve the required build-up. The target plasma will be created by irradiating a solid pellet with a laser beam. Although a deuterium pellet would be superior because of purity, the development of an ammonia pellet was undertaken because it requires a simpler technology. The ammonia target plasma is physically acceptable for the initial experiment. A frozen ammonia pellet, about 100 μm in diameter, will be irradiated with 300-J CO 2 laser, to produce a density of about 10 13 cm -3 and about 1 kV temperature

Studies on Preparation and Characterization of Aluminum Nitride-Coated Carbon Fibers and Thermal Conductivity of Epoxy Matrix Composites

Directory of Open Access Journals (Sweden)

Hyeon-Hye Kim

2017-08-01

Full Text Available In this work; the effects of an aluminum nitride (AlN ceramic coating on the thermal conductivity of carbon fiber-reinforced composites were studied. AlN were synthesized by a wet-thermal treatment (WTT method in the presence of copper catalysts. The WTT method was carried out in a horizontal tube furnace at above 1500 °C under an ammonia (NH3 gas atmosphere balanced by a nitrogen using aluminum chloride as a precursor. Copper catalysts pre-doped enhance the interfacial bonding of the AlN with the carbon fiber surfaces. They also help to introduce AlN bonds by interrupting aluminum oxide (Al2O3 formation in combination with oxygen. Scanning electron microscopy (SEM; Transmission electron microscopy (TEM; and X-ray diffraction (XRD were used to analyze the carbon fiber surfaces and structures at each step (copper-coating step and AlN formation step. In conclusion; we have demonstrated a synthesis route for preparing an AlN coating on the carbon fiber surfaces in the presence of a metallic catalyst.

On the design of thermally loaded fiber optics feedthroughs

Directory of Open Access Journals (Sweden)

Marinković Dragan Z.

2016-01-01

Full Text Available Thermo-mechanical design aspects of various structures exposed to cyclic thermal loading have a crucial impact on their lifetime. This is particularly valid for fiber optics feedthroughs that involve several materials with significantly different thermal expansion ratios. Thermal loading in such structures may give rise to non-trivial thermally induced deformations and therewith stresses, which can be adequately predicted and assessed only by a detailed 3-D numerical simulation. This paper considers a couple of design solutions of fiber optics feedthroughs, which have exhibited certain weaknesses in their application. Numerical simulation by means of the finite element method has been conducted to reveal the weak points of the design.

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.

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.

Effective fiber hypertrophy in satellite cell-depleted skeletal muscle

Science.gov (United States)

McCarthy, John J.; Mula, Jyothi; Miyazaki, Mitsunori; Erfani, Rod; Garrison, Kelcye; Farooqui, Amreen B.; Srikuea, Ratchakrit; Lawson, Benjamin A.; Grimes, Barry; Keller, Charles; Van Zant, Gary; Campbell, Kenneth S.; Esser, Karyn A.; Dupont-Versteegden, Esther E.; Peterson, Charlotte A.

2011-01-01

An important unresolved question in skeletal muscle plasticity is whether satellite cells are necessary for muscle fiber hypertrophy. To address this issue, a novel mouse strain (Pax7-DTA) was created which enabled the conditional ablation of >90% of satellite cells in mature skeletal muscle following tamoxifen administration. To test the hypothesis that satellite cells are necessary for skeletal muscle hypertrophy, the plantaris muscle of adult Pax7-DTA mice was subjected to mechanical overload by surgical removal of the synergist muscle. Following two weeks of overload, satellite cell-depleted muscle showed the same increases in muscle mass (approximately twofold) and fiber cross-sectional area with hypertrophy as observed in the vehicle-treated group. The typical increase in myonuclei with hypertrophy was absent in satellite cell-depleted fibers, resulting in expansion of the myonuclear domain. Consistent with lack of nuclear addition to enlarged fibers, long-term BrdU labeling showed a significant reduction in the number of BrdU-positive myonuclei in satellite cell-depleted muscle compared with vehicle-treated muscle. Single fiber functional analyses showed no difference in specific force, Ca2+ sensitivity, rate of cross-bridge cycling and cooperativity between hypertrophied fibers from vehicle and tamoxifen-treated groups. Although a small component of the hypertrophic response, both fiber hyperplasia and regeneration were significantly blunted following satellite cell depletion, indicating a distinct requirement for satellite cells during these processes. These results provide convincing evidence that skeletal muscle fibers are capable of mounting a robust hypertrophic response to mechanical overload that is not dependent on satellite cells. PMID:21828094

Blood ammonia and glutamine as predictors of hyperammonemic crises in patients with urea cycle disorder.

Science.gov (United States)

Lee, Brendan; Diaz, George A; Rhead, William; Lichter-Konecki, Uta; Feigenbaum, Annette; Berry, Susan A; Le Mons, Cindy; 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, Andreas; Vockley, Jerry; Vockley, Gerard; Kronn, David; Zori, Roberto; Summar, Marshall; Milikien, Douglas A; Marino, Miguel; Coakley, Dion F; Mokhtarani, Masoud; Scharschmidt, Bruce F

2015-07-01

The aim of this study was to examine predictors of ammonia exposure and hyperammonemic crises in patients with urea cycle disorders. The relationships between fasting ammonia, daily ammonia exposure, and hyperammonemic crises were analyzed in >100 patients with urea cycle disorders. Fasting ammonia correlated strongly with daily ammonia exposure (r = 0.764; P 200% (P urea cycle disorder subtype, dietary protein intake, or blood urea nitrogen. Fasting glutamine correlated weakly with daily ammonia exposure assessed as 24-hour area under the curve and was not a significant predictor of hyperammonemic crisis. Fasting ammonia correlates strongly and positively with daily ammonia exposure and with the risk and rate of hyperammonemic crises, suggesting that patients with urea cycle disorder may benefit from tight ammonia control.

Recovery of gold from solutions with ammonia and thiosulfate using activated carbon

OpenAIRE

Vargas, C.; Navarro, Patricio; Araya, Eyleen; Pávez, F.; Alguacil, Francisco José

2006-01-01

The recovery of gold from solutions containing thiosulfate and ammonia using granular activated carbon was studied, evaluating the adsorption and elution stages. The influence of ammonia and thiosulfate concentration and the presence of impurities such as copper and zinc were also evaluated. In the presence of ammonia there was a concentration which maximized the adsorption of gold, while thiosulfate and impurities presence was harmful for the adsorption of gold. During elution, ammonia and t...

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

Applicability of Ammonia Sensors for Controlling Environmental Parameters in Accommodations for Lamb Fattening

Directory of Open Access Journals (Sweden)

F. Javier García-Ramos

2018-01-01

Full Text Available Electrochemical ammonia sensors were used to analyse the existing relationship between the ammonia concentration and ambient levels of both temperature and relative humidity in commercial lamb fattening housing equipped with mechanical ventilation and straw-bedded pens. In the first stage of the experiment, sensors were placed over straw beds covered in lamb urine and analysed under laboratory conditions in order to determine ammonia emission evolution over time; three control temperatures (25, 35, and 50°C were used. A HOBO H8 temperature and relative humidity logger and a Dräger NH3LC-6809680 electrochemical ammonia sensor placed in a Dräger Polytron 7000 gas detector were utilized as sensors. A positive correlation was established between both ammonia emission time and emitted amount with temperature. Additionally, tests were performed in a commercial lamb housing to determine ammonia concentration variation with respect to height from the ground; three ammonia sensors placed at 50, 90, and 135 cm above the ground were used simultaneously. The ammonia concentration significantly decreased as height increased. A 90 cm height was selected, and three ammonia probes were placed in three different pens inside the livestock housing, along with temperature and relative humidity sensors; four different housing ventilation rates were then tested under real conditions over a time period of 4 months. An adjustment polynomial equation between the housing ambient temperature and the ammonia concentration was obtained with R2 = 0.632. In conclusion, a relationship can be established between temperature and ammonia concentration in commercial lamb housing under certain handling conditions, which in turn allows for estimating the ammonia concentration adequately based on the ambient internal temperature.

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.

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

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.

High Ph, Ammonia Toxicity, and the Search for Life on the Jovian Planets

Science.gov (United States)

Deal, P. H.; Souza, K. A.; Mack, H. M.

1975-01-01

The effects of pH and ammonia concentration were studied separately, where possible, on a variety of organisms, including some isolated from natural environments of high pH and/or ammonia concentration. Escherichia coli and Bacillus subtilis are both extremely sensitive to ammonia. An aerobic organism (growth up to pH 11.4) from an alkaline spring is more resistant, but exhibits a toxic response to ammonia at a pH much lower than its maximum for growth. The greatest ammonia resistance has been found in an unidentified organism growing at near neutral pH. Even in this case, however, urvival at ammonia concentrations reasonably expected on the Jovian planets is measured in hours. This is two to three orders of magnitude longer than for E. coli. Results support the tentative conclusion that contamination of the Jovian planets with terrestrial organisms that can grow is unlikely. However, the range of toxic response noted, coupled with the observation that terrestrial life has not been exposed to high ammonia concentrations for millions of years, suggests that adaptation to greater ammonia tolerance may be possible.

Fiber-optical sensor with intensity compensation model in college teaching of physics experiment

Science.gov (United States)

Su, Liping; Zhang, Yang; Li, Kun; Zhang, Yu

2017-08-01

Optical fiber sensor technology is one of the main contents of modern information technology, which has a very important position in modern science and technology. Fiber optic sensor experiment can improve students' enthusiasm and broaden their horizons in college physics experiment. In this paper the main structure and working principle of fiberoptical sensor with intensity compensation model are introduced. And thus fiber-optical sensor with intensity compensation model is applied to measure micro displacement of Young's modulus measurement experiment and metal linear expansion coefficient measurement experiment in the college physics experiment. Results indicate that the measurement accuracy of micro displacement is higher than that of the traditional methods using fiber-optical sensor with intensity compensation model. Meanwhile this measurement method makes the students understand on the optical fiber, sensor and nature of micro displacement measurement method and makes each experiment strengthen relationship and compatibility, which provides a new idea for the reform of experimental teaching.

Oxidative destruction of ammonia for restoration of uranium solution mining sites

International Nuclear Information System (INIS)

Humenick, M.J.; Garwacka, K.

1984-01-01

A laboratory experimental research project was conducted to evaluate the use of chlorine for the oxidative destruction of residual ammonia that may remain in ground water after in-situ uranium solution mining operations. The work tested the idea of injecting high strength calcium hypochlorite solution into the mining zone to convert ammonia to nitrogen gas as a final cleanup process for ammonia removal from the ground water system. This paper details ammonia removal efficiency as a function of chlorine dose, reactant, and product material balances, and how the concept may be used as a final ground water restoration process

Oxidative destruction of ammonia for restoration of uranium solution mining sites

Energy Technology Data Exchange (ETDEWEB)

Humenick, M.J.; Garwacka, K.

1984-02-01

A laboratory experimental research project was conducted to evaluate the use of chlorine for the oxidative destruction of residual ammonia that may remain in ground water after in-situ uranium solution mining operations. The work tested the idea of injecting high strength calcium hypochlorite solution into the mining zone to convert ammonia to nitrogen gas as a final cleanup process for ammonia removal from the ground water system. This paper details ammonia removal efficiency as a function of chlorine dose, reactant, and product material balances, and how the concept may be used as a final ground water restoration process.

Oxidative destruction of ammonia for restoration of uranium solution mining sites

Energy Technology Data Exchange (ETDEWEB)

Humenick, M.J.; Garwacka, K.

1984-01-01

A laboratory experimental research project was conducted to evaluate the use of chlorine for the oxidative destruction of residual ammonia that may remain in ground water after in-situ uranium solution mining operations. The work tested the idea of injecting high strength calcium hypochlorite solution into the mining zone to convert ammonia to nitrogen gas as a final cleanup process for ammonia removal from the ground water system. This paper details ammonia removal efficiency as a function of chlorine dose, reactant, and product material balances, and how the concept may be used as a final ground water restoration process.

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.

Ammonia-hydrogen bromide and ammonia-hydrogen iodide complexes: anion photoelectron and ab initio studies.

Science.gov (United States)

Eustis, S N; Whiteside, A; Wang, D; Gutowski, M; Bowen, K H

2010-01-28

The ammonia-hydrogen bromide and ammonia-hydrogen iodide, anionic heterodimers were studied by anion photoelectron spectroscopy. In complementary studies, these anions and their neutral counterparts were also investigated via ab initio theory at the coupled cluster level. In both systems, neutral NH(3)...HX dimers were predicted to be linear, hydrogen-bonded complexes, whereas their anionic dimers were found to be proton-transferred species of the form, (NH(4)(+)X(-))(-). Both experimentally measured and theoretically predicted vertical detachment energies (VDE) are in excellent agreement for both systems, with values for (NH(4)(+)Br(-))(-) being 0.65 and 0.67 eV, respectively, and values for (NH(4)(+)I(-))(-) being 0.77 and 0.81 eV, respectively. These systems are discussed in terms of our previous study of (NH(4)(+)Cl(-))(-).

Ammonia effect on hydrogenotrophic methanogens and syntrophic acetate oxidizing bacteria

DEFF Research Database (Denmark)

Wang, Han; Fotidis, Ioannis; Angelidaki, Irini

Substrates that contain high ammonia levels can cause inhibition on anaerobic digestion process and unstable biogas production. The aim of the current study was to assess the effects of different ammonia levels on pure strains of (syntrophic acetate oxidizing) SAO bacteria and hydrogenotrophic...... methanogens. Two pure strains of hydrogenotrophic methanogens (i.e: Methanoculleus bourgensis and Methanoculleus thermophiles) and two pure strains of SAO bacteria (i.e: Tepidanaerobacter acetatoxydans and Thermacetogenium phaeum) were inoculated under four different ammonia (0.26, 3, 5 and 7g NH4+-N......, the total incubation periods of hydrogenotrophic methanogens were significantly shorter compared to the SAO bacteria incubation periods. Thus, it seems that hydrogenotrophic methanogens could be equally, if not more, tolerant to high ammonia levels compared to SAO bacteria....

Ammonia scrubber testing during IDMS SRAT and SME processing. Revision 1

International Nuclear Information System (INIS)

Lambert, D.P.

1995-01-01

This report summarizes results of the Integrated DWPF (Defense Waste Processing Facility) Melter System (IDMS) ammonia scrubber testing during the PX-7 run (the 7th IDMS run with a Purex type sludge). Operation of the ammonia scrubber during IDMS Sludge Receipt and Adjustment Tank (SRAT) and Slurry Mix Evaporator (SME) processing has been completed. The ammonia scrubber was successful in removing ammonia from the vapor stream to achieve NH3 concentrations far below the 10 ppM vapor exist design basis during SRAT processing. However, during SME processing, vapor NH3 concentrations as high as 450 ppM were measured exiting the scrubber. Problems during the SRAT and SME testing were vapor bypassing the scrubber and inefficient scrubbing of the ammonia at the end of the SME cycle (50% removal efficiency; 99.9% is design basis efficiency)

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

DEFF Research Database (Denmark)

Zhang, Yifeng; Angelidaki, Irini

2015-01-01

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/m2 /day and current density...... of 4.33 A/m2 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...

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.

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.

Recovery of gold from solutions with ammonia and thiosulfate using activated carbon

International Nuclear Information System (INIS)

Vargas, C.; Navarro, P.; Araya, E.; Pavez, F.; Alguacil, F. J.

2006-01-01

The recovery of gold from solutions containing thiosulfate and ammonia using granular activated carbon was studied,evaluating the adsorption and elution stages. The influence of ammonia and thiosulfate concentration and the presence of impurities such as copper and zinc were also evaluated. In the presence of ammonia there was a concentration which maximized the adsorption of gold, while thiosulfate and impurities presence was harmful for the adsorption of gold. during elution, ammonia and thiosulfate concentration, pH regulator and temperature were evaluated. Ammonia favored the process as long as thiosulfate showed a maximum starting from which the elution diminishes. The effect of the pH regulator was very important; If was revealed that when the pH was regulated with caustic ammonia, a synergic effect appeared which favored the elution. Temperature favored the elution process, with activation energy of 9.13 kJ/mol. (Author) 25 refs

Emission of ammonia from indoor concrete wall and assessment of human exposure.

Science.gov (United States)

Bai, Z; Dong, Y; Wang, Z; Zhu, T

2006-04-01

Addition of urea-based antifreeze admixtures during cement mixing can make it possible to produce concrete cement in construction of buildings in cold weather; this, however, has led to increasing indoor air pollution due to continuous transformation and emission from urea to gaseous ammonia in indoor concrete wall. It is believed that ammonia is harmful to human body and exposure to ammonia can cause some serious symptoms such as headaches, burns, and even permanent damage to the eyes and lungs. In order to understand the emission of ammonia from indoor concrete wall in civil building and assess the health risk of people living in these buildings, the experimental pieces of concrete wall were first prepared by concreting cement and urea-based antifreeze admixtures to simulate the indoor wall in civil building in this work. Then environmental chamber was adopted for studying the effect of temperature, relative humility and air exchange rate on emission of ammonia from experimental pieces of concrete wall. Also the field experiment was made at selected rooms in given civil buildings. Exposure and potential dose of adult and children exposed to indoor/outdoor ammonia in summer and in winter are calculated and evaluated by using Scenario Evaluation Approach. The results indicated that high air exchange rate leads to decreased ammonia concentration, and elevation of temperature causes increasing ammonia concentration and volatilizing rate in chamber. The complete emission of ammonia from the wall containing urea-based antifreeze admixtures needs more than 10 years in general. Ventilating or improving air exchange can play a significant role in reducing ammonia concentration in actual rooms in field experiments. Urea-based antifreeze admixtures in concrete wall can give rise to high exposure and potential dose, especially in summer. Generally, adults have a high potential dose than children, while children have personal average dose rate beyond adults in the same

Ammonia corrodes solar modules; Salmiakgeist greift Module an

Energy Technology Data Exchange (ETDEWEB)

Petzold, Katrin

2011-07-01

Ammonia is an aggressive gas produced in animal shelters, which may cause corrosion of solar modules. Various institutions, e.g. DLG and TUeV Rheinland, therefore offer an ammonia test for solar modules. The TUeV Rheinland recently commissioned a walk-in test chamber and now issues an official seal of approval, while the DLG doubts the practical value of the test.

Modelling agro-forestry scenarios for ammonia abatement in the landscape

International Nuclear Information System (INIS)

Bealey, W J; Braban, C F; Famulari, D; Theobald, M R; Reis, S; Sutton, M A; Loubet, B; Reay, D S

2014-01-01

Ammonia emissions from livestock production can have negative impacts on nearby protected sites and ecosystems that are sensitive to eutrophication and acidification. Trees are effective scavengers of both gaseous and particulate pollutants from the atmosphere making tree belts potentially effective landscape features to support strategies aiming to reduce ammonia impacts. This research used the MODDAS-THETIS a coupled turbulence and deposition turbulence model, to examine the relationships between tree canopy structure and ammonia capture for three source types—animal housing, slurry lagoon, and livestock under a tree canopy. By altering the canopy length, leaf area index, leaf area density, and height of the canopy in the model the capture efficiencies varied substantially. A maximum of 27% of the emitted ammonia was captured by tree canopy for the animal housing source, for the slurry lagoon the maximum was 19%, while the livestock under trees attained a maximum of 60% recapture. Using agro-forestry systems of differing tree structures near ‘hot spots’ of ammonia in the landscape could provide an effective abatement option for the livestock industry that complements existing source reduction measures. (paper)

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

Gold cementation with zinc powder from leaching solutions with ammonia-thiosulphate

International Nuclear Information System (INIS)

Navarro, P.; Vargas, C.; Alvarez, R.; Alguacil, F. J.

2005-01-01

The cementation of gold with powder of zinc, from solutions with thiosulphate and ammonia, was studied. the variables evaluated were: thiosulphate concentration, ammonia concentration, pH, copper concentration and zinc concentration. the results have revealed the great importance of ammonia/thiosulphate relationship in this process and that the impurities presence like copper and zinc will to inhibit the cementation process. (Author) 16 refs

Refractive Index Measurement of Fibers Through Fizeau Interferometry

Science.gov (United States)

2013-08-01

Ottawa, Canada) Infinity3-1 Strip heaters McMaster -Carr (Chicago, IL) 35475K722 Temperature controller Glas-Col, LLC (Terre-Haute, IN) DigiTrol II...optic coefficient was also measured for representative samples of both the PP monofilament and nylon ribbon fibers. The undrawn PP monofilament...nylon, the coefficient of thermal expansion of polymers can often be used to estimate their respective dn/dT (13). Using this method, the expected