Total Protein Content Determination of Microalgal Biomass by Elemental Nitrogen Analysis and a Dedicated Nitrogen-to-Protein Conversion Factor

Energy Technology Data Exchange (ETDEWEB)

Laurens, Lieve M [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Olstad-Thompson, Jessica L [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Templeton, David W [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

2018-04-02

Accurately determining protein content is important in the valorization of algal biomass in food, feed, and fuel markets, where these values are used for component balance calculations. Conversion of elemental nitrogen to protein is a well-accepted and widely practiced method, but depends on developing an applicable nitrogen-to-protein conversion factor. The methodology reported here covers the quantitative assessment of the total nitrogen content of algal biomass and a description of the methodology that underpins the accurate de novo calculation of a dedicated nitrogen-to-protein conversion factor.

Nuclear method for determination of nitrogen depth distributions in single seeds. [/sup 14/N tracer technique

Energy Technology Data Exchange (ETDEWEB)

Sundqvist, B; Gonczi, L; Koersner, I; Bergman, R; Lindh, U

1974-01-01

(d,p) reactions in /sup 14/N were used for probing single kernels of seed for nitrogen content and nitrogen depth distributions. Comparison with the Kjeldahl method was made on individual peas and beans. The results were found to be strongly correlated. The technique to obtain depth distributions of nitrogen was also used on high- and low-lysine varieties of barley for which large differences in nitrogen distributions were found.

Radioactivation method for simultaneous determination of nitrogen, phosphorus and potassium content in plants and fertilizers

International Nuclear Information System (INIS)

Kovtun, J.L.; Miroshnikova, N.N.; Saveliev, I.B.; Sidorov, A.V.; Srapeniants, R.A.; Tsagolov, K.S.

1981-01-01

According to the invention, the radioactivation method for simultaneous determination of the nitrogen, phosphorus and potassium content in plants and fertilizers consists in exposing samples to be analyzed and standard samples to neutron irradiation and recording the spectra of the gamma radiation induced in said samples, whereupon the samples are laid aside for a period of time determined by the half-life of the interfering isotope. This is followed by again recording the spectra of the samples being analyzed and of the standard samples and superposing the first and second spectra of the samples being analyzed and of the standard samples. These spectra are then shifted relative to each other along the energy axis, and the contents of the elements being analyzed are determined by thus comparing the spectra of the samples being analyzed and of the standard samples

Continuous determination of nitric oxide and nitrogen dioxide in the atmosphere

Energy Technology Data Exchange (ETDEWEB)

Yanagisawa, S; Yamate, N; Mitsuzawa, S; Mori, M

1966-10-01

Continuous determinations of nitric oxide and nitrogen dioxide in that atmospheric air by the use of a modified Saltzman reagent is described. Measurement was made intermittently, once every 30 min., by an automatic continuous analyzer equipped with a single-path colorimeter. The response of the analyzer was obtained as an average of the concentration of nitrogen oxides over a period of 25 min. Two bubblers were used for absorbing nitrogen oxides into the modified Saltzman reagent, whose transmittance was measured for the determination. One bubbler was designed to absorb nitrogen dioxide, and the other, nitric oxide plus nitrogen dioxide after the oxidation of the nitric oxide by permanganate. The oxidizing efficiency of the permanganate was 96-100%. The acetic acid in the Saltzman reagent was replaced with n-propyl alcohol in the modified Saltzman reagent; the spontaneous coloration and corrosive quality of the reagent was decreased by this substitution. The concentration of nitric oxide was obtained from the difference between the two responses of the analyzer, while the concentration of nitrogen dioxide could be read directly from the indication of the recorder. The transmittance ratio method was applied to the measurements, accurate determinations were possible, even at high blank values. Therefore, the reagent was used repeatedly by cycling it on the basis of measuring the difference in the coloration of the reagent before and after the absorption of nitrogen oxides. The analyzer could be used for a long period without changing the reagent.

Utilization of tritiated water dilution technique in determination of nitrogen partitioning in cashmere goats

International Nuclear Information System (INIS)

Wang Linfeng; Yang Gaiqing; Liu Ping; Zhang Shijun

2010-01-01

In order to investigate nitrogen partitioning in local cashmere goats, six Inner Mogolia White Cashmere goats between 2 to 2.5 years old were used to determine the nitrogen partitioning in cashmere goats. The total retained nitrogen (TN) in body, distribution of body nitrgen and hair nitrogen were measured by general digestive and metabolism method combined with tritiated water dilution technique. Results showed that the combined methods were ideal for determining body nitrgen (BN) and hair nitrogen (fur nitrogen, FN) of Cashmere goats. There were obvious significance between BN and FN in different seasons. In telogen, BN and FN partitioning was 75.7% ± 0.62% and 24.3% ± 0.62%, respectively. Whereas, it changed to 66.6% ± 2.2% and 33.4% ± 2.2% in anagen. BN partitioning decreased when the season changed from telogen to anagen, while FN partitioning increased, which indicated that more nitrogen substance was partitioned to body growth in telogen, and more nitrogen substance was distribute to cashmere growth in anagen. These transformation were related to the changing of photoperiod and some hormones, such as melatonin (MT), prolactin (PRL) and IGF-I. It could be concluded that tritiated water dilution technique can be used to detect body protein content as well as BN, combining general digestive and metabolism experiment, FN partitoning can be determined. BN and FN partitoning varied with the season in cashmere goats because of hormones changing. (authors)

Nitrogen determination on tomato ( Lycopersicon esculentum Mill ...

African Journals Online (AJOL)

In order to investigate the effectiveness of a new method based on color image analysis and the Minolta SPAD-502 chlorophyll meter for the diagnosis of nitrogen deficiencies of tomato seedlings, a field experiment was conducted. In this study, five levels of nitrogen fertilization were established so as to induce nitrogen ...

Determination of nitrite, nitrate and total nitrogen in vegetable samples

Directory of Open Access Journals (Sweden)

Manas Kanti Deb

2007-04-01

Full Text Available Yellow diazonium cation formed by reaction of nitrite with 6-amino-1-naphthol-3-sulphonic acid is coupled with β-naphthol in strong alkaline medium to yield a pink coloured azo dye. The azo-dyes shows absorption maximum at 510 nm with molar absorptivity of 2.5 ×104 M-1 cm-1. The dye product obeys Beer's law (correlation coefficient = 0.997, in terms of nitrite concentration, up to 2.7 μg NO2 mL-1. The above colour reaction system has been applied successfully for the determination of nitrite, nitrate and total nitrogen in vegetable samples. Unreduced samples give direct measure for nitrite whilst reduction of samples by copperized-cadmium column gives total nitrogen content and their difference shows nitrate content in the samples. Variety of vegetables have been tested for their N-content (NO2-/NO3-/total-N with % RSD ranging between 1.5 to 2.5 % for nitrite determination. The effects of foreign ions in the determination of the nitrite, nitrate, and total nitrogen have been studied. Statistical comparison of the results with those of reported method shows good agreement and indicates no significant difference in precision.

On the problem of activation determination of nitrogen in petroleum

International Nuclear Information System (INIS)

Botvina, A.Ya.; Kazachevskij, I.V.; Sokol'skij, V.V.

1974-01-01

The determination of nitrogen in individual hydrocarbon feedstocks and petroleums by irradiation with fast neutrons was discussed, and the N content of 12 Kazakh petroleums was determined by this method, ranging from 0.062% in Martyshi petroleum to 0.173% in Kumsai P 1 petroelum. The amount of 13 N formed in secondary reactions with protons, designated ''false'' N, was shown to depend linearly on Wsub(C)Wsub(H)Rsub(p), where Wsub(H) and Wsub(C) are the relative weight contents of H and C in a given substance respectively, and Rsub(p) is the proton path. The amounts of ''false'' N were determined by the method of A. Botvina et al (1971), and were tabulated along with values of Rsub(p) and Wsub(C)Wsub(H)Rsub(p) for 5 materials. The simultaneous determination of C, N, and O, proposed by T. Blankova and V. Rusyaev (1971) was not considered worthwhile because C and H could be determined only within 10-15% by the method

Determination of carbon and nitrogen in silicon and germanium

International Nuclear Information System (INIS)

Gebauhr, W.; Martin, J.

1975-01-01

The essential aim of this study is to examine the various technical and economic problems encountered in the determination of carbon and nitrogen in silicon and germanium, for this is in a way an extension of the discussion concerning the presence of oxygen in these two elements. The greater part of the study is aimed at drawing up a catalogue of the methods of analysis used and of the results obtained so far

A new method for the determination of the nitrogen content of nitrocellulose based on the molar ratio of nitrite-to-nitrate ions released after alkaline hydrolysis

Energy Technology Data Exchange (ETDEWEB)

Alinat, Elodie, E-mail: elodie.alinat@chimie-paristech.fr [PSL Research University, Chimie ParisTech, Laboratory of Physicochemistry of Electrolytes, Colloids and Analytical Sciences (PECSA), 11 rue Pierre et Marie Curie, 75005 Paris (France); Central Laboratory of Police Prefecture (LCPP), 39 bis rue de Dantzig, 75015 Paris (France); CNRS, UMR 7195 PECSA, 11 rue Pierre et Marie Curie, 75005 Paris (France); Sorbonne Universités, UPMC Univ Paris 06, LBM, 4 place Jussieu, F-75005 Paris (France); Delaunay, Nathalie, E-mail: nathalie.delaunay@espci.fr [PSL Research University, Chimie ParisTech, Laboratory of Physicochemistry of Electrolytes, Colloids and Analytical Sciences (PECSA), 11 rue Pierre et Marie Curie, 75005 Paris (France); CNRS, UMR 7195 PECSA, 11 rue Pierre et Marie Curie, 75005 Paris (France); Sorbonne Universités, UPMC Univ Paris 06, LBM, 4 place Jussieu, F-75005 Paris (France); Archer, Xavier, E-mail: xavier.archer@interieur.gouv.fr [Central Laboratory of Police Prefecture (LCPP), 39 bis rue de Dantzig, 75015 Paris (France); Mallet, Jean-Maurice, E-mail: jean-maurice.mallet@es.fr [École Normale Supérieure-PSL Research University, Département de Chimie, 24 rue Lhomond, 75005 Paris (France); Sorbonne Universités, UPMC Univ Paris 06, LBM, 4 place Jussieu, F-75005 Paris (France); CNRS, UMR 7203 LBM, F-75005 Paris (France); Gareil, Pierre, E-mail: pierre.gareil@chimie-paristech.fr [PSL Research University, Chimie ParisTech, Laboratory of Physicochemistry of Electrolytes, Colloids and Analytical Sciences (PECSA), 11 rue Pierre et Marie Curie, 75005 Paris (France); CNRS, UMR 7195 PECSA, 11 rue Pierre et Marie Curie, 75005 Paris (France); Sorbonne Universités, UPMC Univ Paris 06, LBM, 4 place Jussieu, F-75005 Paris (France)

2015-04-09

Highlights: • New insights into the nitrocellulose alkaline denitration mechanism. • Linear correlation for molar ratio of nitrite-to-nitrate ions and nitrogen content. • Capillary electrophoresis monitoring of nitrite and nitrate ions. • Applications to explosive and non-explosive nitrocellulose-containing samples. • Improved performances (including safety) over classical methods. - Abstract: A new method was proposed to determine the nitrogen content of nitrocelluloses (NCs). It is based on the finding of a linear relationship between the nitrogen content and the molar ratio of nitrite-to-nitrate ions released after alkaline hydrolysis. Capillary electrophoresis was used to monitor the concentration of nitrite and nitrate ions. The influences of hydrolysis time and molar mass of NC on the molar ratio of nitrite-to-nitrate ions were investigated, and new insights into the understanding of the alkaline denitration mechanism of NCs, underlying this analytical strategy is provided. The method was then tested successfully with various explosive and non-explosive NC-containing samples such as various daily products and smokeless gunpowders. Inherently to its principle exploiting a concentration ratio, this method shows very good repeatability in the determination of nitrogen content in real samples with relative standard deviation (n = 3) inferior to 1.5%, and also provides very significant advantages with respect to sample extraction, analysis time (1 h for alkaline hydrolysis, 3 min for electrophoretic separation), which was about 5 times shorter than for the classical Devarda's method, currently used in industry, and safety conditions (no need for preliminary drying NC samples, mild hydrolysis conditions with 1 M sodium hydroxide for 1 h at 60 °C)

A new method for the determination of the nitrogen content of nitrocellulose based on the molar ratio of nitrite-to-nitrate ions released after alkaline hydrolysis

International Nuclear Information System (INIS)

Alinat, Elodie; Delaunay, Nathalie; Archer, Xavier; Mallet, Jean-Maurice; Gareil, Pierre

2015-01-01

Highlights: • New insights into the nitrocellulose alkaline denitration mechanism. • Linear correlation for molar ratio of nitrite-to-nitrate ions and nitrogen content. • Capillary electrophoresis monitoring of nitrite and nitrate ions. • Applications to explosive and non-explosive nitrocellulose-containing samples. • Improved performances (including safety) over classical methods. - Abstract: A new method was proposed to determine the nitrogen content of nitrocelluloses (NCs). It is based on the finding of a linear relationship between the nitrogen content and the molar ratio of nitrite-to-nitrate ions released after alkaline hydrolysis. Capillary electrophoresis was used to monitor the concentration of nitrite and nitrate ions. The influences of hydrolysis time and molar mass of NC on the molar ratio of nitrite-to-nitrate ions were investigated, and new insights into the understanding of the alkaline denitration mechanism of NCs, underlying this analytical strategy is provided. The method was then tested successfully with various explosive and non-explosive NC-containing samples such as various daily products and smokeless gunpowders. Inherently to its principle exploiting a concentration ratio, this method shows very good repeatability in the determination of nitrogen content in real samples with relative standard deviation (n = 3) inferior to 1.5%, and also provides very significant advantages with respect to sample extraction, analysis time (1 h for alkaline hydrolysis, 3 min for electrophoretic separation), which was about 5 times shorter than for the classical Devarda's method, currently used in industry, and safety conditions (no need for preliminary drying NC samples, mild hydrolysis conditions with 1 M sodium hydroxide for 1 h at 60 °C)

14 MeV INAA nitrogen determination in coal conversion liquids

International Nuclear Information System (INIS)

Ehmann, W.D.; Khalil, S.R.

1980-01-01

Fast neutron activation analysis has been used for the direct determination of nitrogen in coal conversion liqui-ds. In our previous work on coals, solid standards such as N-1-napthylacetamide, NBS SRM 912 urea and NBS SRM 148 nicotinic acid were used for nitrogen determinations. In this work, a set of organic liquids was selected and evaluated for use as nitrogen standards in the analysis of coal-derived liquids. The use of the liquid standards minimizes problems associated with maintaining uniform irradation and counting geometries and self absorption differences related to varying matrix densities. The standard liquids were selected using criteria of high boiling point, well-defined stoichiometry, high-purity, non-hygroscopic nature and simple C-H-N elemental compositions. Excellent agreement between the 14 MeV INAA data and calculated stoichiometric values has been demonstrated for liquids with nitrogen contents from 1.89 to 39.95%. The liquid standards have been used to determine nitrogen in a set of typical coal conversion liquids and several international standards. (author)

Determination of isotopic identity of nitrogen fixed by Frankia associated with the genus Alnus

International Nuclear Information System (INIS)

Kurdali, F.; Domenach, A.M.; Daniere, C.; Bardin, R.

1988-01-01

To use the 15 N natural abundance method to evaluate the symbiotic nitrogen fixation by actinorhizal trees, it is necessary to determine the isotopic identity of assimilated nitrogen from two sources: the soil and the air. This study reports an isotopic value of fixed nitrogen by two alder species (Alnus Incana(L.) Moench and Alnus glutinosa(L.) Gaertn.) growing on nitrogen-free medium in greenhouse experiments. The δ 15 N value of the aerial parts was -2. This value was stable with time and did not depend on the Frankia strains used. This value could be used to estimate the nitrogen fixation in the natural ecosystem. Other parameters such as the mobilization of nitrogen reserves and the choice of the reference plant must be investigated to apply this method. The nodules of these two alder species were enriched in 15 N relative to the rest of the plant but there was no relationship between symbiotic effectiveness of Frankia strains and 15 N enrichment of nodules. On the other hand, for naturally growing trees, an enrichment in 15 N was found primarily in the vesicles of nodules that are the sites of nitrogen fixation. 37 refs., 4 figs., 3 tabs. (author)

A sensitive spectrophotometric determination of nitrogen dioxide in the working atmosphere

Directory of Open Access Journals (Sweden)

Prachi Parmar

2009-12-01

Full Text Available In the present investigation, a simple and sensitive spectrophotometric method for the determination of nitrogen dioxide in various environmental samples is described. Nitrogen dioxide in air was fixed as nitrite ion in alkaline sodium arsenite absorbing solution. The nitrite formed was diazotized with p−aminoacetophenone in acidic medium which was subsequently coupled with phloroglucinol to give yellow−orange dye in alkaline medium having an absorption maximum at 420 nm. Beer’s law was obeyed in the range of 0.008 − 0.12 μg mL-1 of nitrogen dioxide and has a molar absorptivity of 2.875 x 105 L mol-1 cm-1. Optimum reaction conditions for diazotization, full colour development and the effect of variables like temperature, time and pH have been studied. Detailed studies to check the collection efficiency and NO2:NO2- stoichiometric ratio has been carried out. The reaction has been successfully applied for the detection of nitrogen dioxide in cigarette smoke, scooter exhaust, and workroom air.

Determining pomegranate water and nitrogen requirements with drip irrigation

Science.gov (United States)

Despite being an ancient crop there is limited knowledge on the water and nitrogen (N) requirements of pomegranate. We conducted research at the University of California, Kearney Agricultural Research and Extension Center (KARE) to determine the water and nitrogen requirements of a developing pomegr...

Determination of daminozide residues in apples using gas chromatography with nitrogen-phosphorus detection

NARCIS (Netherlands)

Brinkman, J.H.W.; Dijk, A.G. van; Wagenaar, R.; Quirijns, J.K.

1996-01-01

A method was developed for the determination of daminozide in apples using gas chromatography (GC) with nitrogen-phosphorus detection (NPD). Daminozide is hydrolysed to 1,1-dimethylhydrazine (UDMH) by alkaline digestion. The UDMH generated is distilled from the apple matrix, derivatized with

Synthesis of nitrogen-doped graphene via solid microwave method

Energy Technology Data Exchange (ETDEWEB)

Zhang, Li, E-mail: zhangli379@sohu.com [School of Electrical Engineering, Dalian University of Technology, Dalian, Liaoning 116024 (China); Ji, Bingcheng, E-mail: debbo.jee@outlook.com [School of Electrical Engineering, Dalian University of Technology, Dalian, Liaoning 116024 (China); Wang, Kai [School of Electrical Engineering, Dalian University of Technology, Dalian, Liaoning 116024 (China); Song, Jinyan [School of Information Engineering, Dalian Ocean University, Dalian, Liaoning 116024 (China)

2014-07-01

Graphical abstract: - Highlights: • A direct solid microwave method is developed to prepare nitrogen-doped graphene. • The method consists of two steps, namely the functionalization and microwave irradiation. • Melamine can serve as not only functionalizing agent but also nitrogen source. - Abstract: In this paper, we propose a solid microwave-mediated method for scalable production of nitrogen-doped graphene sheets (NGS) using low-cost industrial material melamine as functionalizing agent and nitrogen source. The strong interaction of microwaves with graphene oxide has been fully utilized to generate in situ heating that induces the decompose melamine and nitrogen doping of graphene. The morphology, structure, and components of the as-produced nitrogen-doped graphene are characterized by scanning electron microscopy (SEM), transmission electron microscope (TEM), Brunauer–Emmett–Teller (BET), pore-size distribution (PSD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectra (XPS), X-ray diffraction (XRD), and Raman spectroscopy. The results show NGS can be successfully synthesized via this strategy.

Synthesis of nitrogen-doped graphene via solid microwave method

International Nuclear Information System (INIS)

Zhang, Li; Ji, Bingcheng; Wang, Kai; Song, Jinyan

2014-01-01

Graphical abstract: - Highlights: • A direct solid microwave method is developed to prepare nitrogen-doped graphene. • The method consists of two steps, namely the functionalization and microwave irradiation. • Melamine can serve as not only functionalizing agent but also nitrogen source. - Abstract: In this paper, we propose a solid microwave-mediated method for scalable production of nitrogen-doped graphene sheets (NGS) using low-cost industrial material melamine as functionalizing agent and nitrogen source. The strong interaction of microwaves with graphene oxide has been fully utilized to generate in situ heating that induces the decompose melamine and nitrogen doping of graphene. The morphology, structure, and components of the as-produced nitrogen-doped graphene are characterized by scanning electron microscopy (SEM), transmission electron microscope (TEM), Brunauer–Emmett–Teller (BET), pore-size distribution (PSD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectra (XPS), X-ray diffraction (XRD), and Raman spectroscopy. The results show NGS can be successfully synthesized via this strategy

Determination of nitrogen in food stuffs using 14-MeV neutrons

International Nuclear Information System (INIS)

Shaddad, I.; Habbani, F.

1994-03-01

The neutron activation method was used for the determination of nitrogen in local food stuffs ( sorghum, grains, beans, nuts, wheat and sesame ). The 14 N(n,2n) 13 N reaction was used in this analysis. The protein content obtained ranged from 8% to 50%. The results of these measurements were compared with others obtained for the same samples using Kjeldahl chemical method. The comparison showed that the two measurements were in good agreement. An effort was also made to optimise the method with regard to sample irradiation and measurement acquisition times. (author). tabs

An efficient absorbing system for spectrophotometric determination of nitrogen dioxide

Science.gov (United States)

Kaveeshwar, Rachana; Amlathe, Sulbha; Gupta, V. K.

A simple and sensitive spectrophotometric method for determination of atmospheric nitrogen dioxide using o-nitroaniline as an efficient absorbing, as well as diazotizing, reagent is described. o-Nitroaniline present in the absorbing medium is diazotized by the absorbed nitrite ion to form diazonium compound. This is later coupled with 1-amino-2-naphthalene sulphonic acid (ANSA) in acidic medium to give red-violet-coloured dye,having λmax = 545 nm. The isoamyl extract of the red azo dye has λmax = 530 nm. The proposed reagents has ≈ 100% collection efficiency and the stoichiometric ratio of NO 2:NO 2- is 0.74. The other important analytical parameters have been investigated. By employing solvent extraction the sensitivity of the reaction was increased and up to 0.03 mg m -3 nitrogen dioxide could be estimated.

Determination of the concentration dependent diffusion coefficient of nitrogen in expanded austenite

DEFF Research Database (Denmark)

Christiansen, Thomas; Somers, Marcel A. J.

2008-01-01

The concentration dependent diffusion coefficient of nitrogen in expanded austenite was determined from of the rate of retracting nitrogen from thin initially N-saturated coupons. Nitrogen saturated homogeneous foils of expanded austenite were obtained by nitriding AISI 304 and AISI 316 in pure...... in the composition range where nitrogen can be extracted by hydrogen gas at the diffusion temperature. Numerical simulation of the denitriding experiments shows that the thus determined concentration dependent diffusion coefficients are an accurate approximation of the actual diffusivity of nitrogen in expanded...... ammonia at 693 K and 718 K. Denitriding experiments were performed by equilibrating the foils with a successively lower nitrogen activity, as imposed by a gas mixture of ammonia and hydrogen. The concentration dependent diffusion coefficient of nitrogen in expanded austenite was approximated...

Method for optical 15N analysis of small amounts of nitrogen gas released from an automatic nitrogen analyzer

International Nuclear Information System (INIS)

Arima, Yasuhiro

1981-01-01

A method of optical 15 N analysis is proposed for application to small amounts of nitrogen gas released from an automatic nitrogen analyzer (model ANA-1300, Carlo Erba, Milano) subjected to certain set modifications. The ANA-1300 was combined with a vacuum line attached by a molecular sieve 13X column. The nitrogen gas released from the ANA-1300 was introduced with a carrier gas of helium into the molecular sieve column which was pre-evacuated at 10 -4 Torr and cooled with outer liquid nitrogen. After removal of the helium by evacuation, the nitrogen gas fixed on the molecular sieve was released by warming the column, and then, it was sealed into pre-evacuated pyrex glass tubes at 4.5 - 5.0 Torr. In the preparation of discharge tubes, contamination of unlabelled nitrogen occurred from the carrier gas of standard grade helium, and the relative lowering of the 15 N value by it was estimated to be less than 1% when over 700 μg nitrogen was charged on the ANA-1300; when 200 μg nitrogen was charged, it was about 3.5%. However, the effect of the contamination could be corrected for by knowing the amount of contaminant nitrogen. In the analysis of plant materials by the proposed method, the coefficient of variation was less than 2%, and no significant difference was observed between results given by the present method and by the ordinary method in which samples were directly pyrolyzed in the discharge tubes by the Dumas method. The present method revealed about 1.5 μg of cross-contaminated nitrogen and was applicable to more than 200 μg of sample nitrogen. (author)

Determination of Meteorite Porosity Using Liquid Nitrogen

Science.gov (United States)

Kohout, T.; Kletetschka, G.; Pesonen, L. J.; Wasilewski, P. J.

2005-01-01

We introduce a new harmless method for porosity measurement suitable for meteorite samples. The method is a modification of the traditional Archimedean method based on immersion of the samples in a liquid medium like water or organic liquids. In our case we used liquid nitrogen for its chemically inert characteristics.

Evaluation of Image Processing Technique for Measuring of Nitrogen and Yield in Paddy Rice and Comparing it with Standard Methods

Directory of Open Access Journals (Sweden)

M.R Larijani

2011-09-01

Full Text Available In order to use new and low cost methods in precision agriculture, nitrogen should be supplied for plants on time and precisely. For determining the required nitrogen of paddy rice in the clustering stage, a series of experiments were conducted using three different methods of: image processing, kjeldahl and chlorophyll meter set (SPAD-502, in a randomized complete block design with three replications during 2010 at Rice Research Center of Tonekabon, Iran. Four experimental treatments were different level of fertilizer (Urea with 46% nitrogen. In the clustering stage, some images from rice plants were taken vertically by a digital camera and were analyzed using image processing technique. Simultaneously the chlorophyll index of plants was measured by SPAD-502 chlorophyll meter set and the percentage amount of nitrogen was measured using of the so called kjeldahl laboratory method. The results showed that the three methods of determining nitrogen of rice plant were highly correlated. Moreover, the correlation among the three methods and crop yield were almost the same. In general, the method of image processing could have a high potential for nitrogen management in the field, while this method was low-cost, faster and also nondestructive in comparison to the other methods.

Semi-microdetermination of nitrogen in actinide compounds by Dumas method

International Nuclear Information System (INIS)

Nagar, M.S.; Ruikar, P.B.; Subramanian, M.S.

1986-01-01

This report describes the application of the Dumas method for the semi-micro determination of nitrogen in actinide compounds and actinide complexes with organic ligands. The usual set up has been modified to make it adaptable for glove box operations. The carbon dioxide generator and nitrometer assemblies were located outside the glove box while the reaction tube and combustion furnaces were housed inside. The nitrogen gas collected in the nitrometer was read with the help of a travelling microscope with a vernier attachment fitted in front of the nitrometer burette. The set up was standardised using acetanilide and employed for the determination of nirtogen in various substances such as uranium nitride, and a variety of substituted quinoline and pyrazolone derivatives of actinides as well as some ternary uranium-PMBR-sulphoxide complexes. Full details of the technique and the analytical data obtained are contained in this report. (author)

Technical Note: Comparison between a direct and the standard, indirect method for dissolved organic nitrogen determination in freshwater environments with high dissolved inorganic nitrogen concentrations

DEFF Research Database (Denmark)

Graeber, Daniel; Gelbrecht, Jörg; Kronvang, Brian

2012-01-01

Research on dissolved organic nitrogen (DON) in aquatic systems with high dissolved inorganic nitrogen (DIN, the sum of NO3–, NO2– and NH4+) concentrations is often hampered by high uncertainties regarding the determined DON concentration. The reason is that DON is determined indirectly...... accuracy at high DIN : TDN ratios, we investigated the DON measurement accuracy of this standard approach according to the DIN : TDN ratio and compared it to the direct measurement of DON by size-exclusion chromatography (SEC) for freshwater systems. For this, we used standard compounds and natural samples...... separation of DON from DIN. For SEC, DON recovery rates were 91–108% for five pure standard compounds and 89–103% for two standard compounds, enriched with DIN. Moreover, SEC resulted in 93–108% recovery rates for DON concentrations of natural samples at a DIN : TDN ratio of 0.8 and the technique...

Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory : evaluation of alkaline persulfate digestion as an alternative to Kjeldahl digestion for determination of total and dissolved nitrogen and phosphorus in water

Science.gov (United States)

Patton, Charles J.; Kryskalla, Jennifer R.

2003-01-01

Alkaline persulfate digestion was evaluated and validated as a more sensitive, accurate, and less toxic alternative to Kjeldahl digestion for routine determination of nitrogen and phosphorus in surface- and ground-water samples in a large-scale and geographically diverse study conducted by U.S. Geological Survey (USGS) between October 1, 2001, and September 30, 2002. Data for this study were obtained from about 2,100 surface- and ground-water samples that were analyzed for Kjeldahl nitrogen and Kjeldahl phosphorus in the course of routine operations at the USGS National Water Quality Laboratory (NWQL). These samples were analyzed independently for total nitrogen and total phosphorus using an alkaline persulfate digestion method developed by the NWQL Methods Research and Development Program. About half of these samples were collected during nominally high-flow (April-June) conditions and the other half were collected during nominally low-flow (August-September) conditions. The number of filtered and whole-water samples analyzed from each flow regime was about equal.By operational definition, Kjeldahl nitrogen (ammonium + organic nitrogen) and alkaline persulfate digestion total nitrogen (ammonium + nitrite + nitrate + organic nitrogen) are not equivalent. It was necessary, therefore, to reconcile this operational difference by subtracting nitrate + nitrite concentra-tions from alkaline persulfate dissolved and total nitrogen concentrations prior to graphical and statistical comparisons with dissolved and total Kjeldahl nitrogen concentrations. On the basis of two-population paired t-test statistics, the means of all nitrate-corrected alkaline persulfate nitrogen and Kjeldahl nitrogen concentrations (2,066 paired results) were significantly different from zero at the p = 0.05 level. Statistically, the means of Kjeldahl nitrogen concentrations were greater than those of nitrate-corrected alkaline persulfate nitrogen concentrations. Experimental evidence strongly

A simple and rapid gas chromatographic method for the determination of dissolved deuterium and nitrogen in heavy water coolant of a nuclear reactor

International Nuclear Information System (INIS)

Nair, B.K.S.

1976-01-01

A known volume of a heavy water sample is equilibrated with a known volume of pure helium gas at atmospheric pressure in a sample tube. The dissolved gases evolve into the helium and distribute themselves between the gaseous and liquid phases according to their equilibrium partial pressures. These partial pressures of the gases in the equilibrium gas mixture are determined by analysing it gas-chromatographically. From these analytical data and the absorption coefficients of deuterium and nitrogen, their original concentrations in heavy water are calculated. Corrections for the increase in the total pressure of the gaseous phase owing to evolved gases are calculated and found to be negligible. Air contamination during sampling and analysis can be detected by the presence of the oxygen peak in the chromatogram and corrected for. The calculation is facilitated by programming it on an electronic calculator. The method is much simpler and faster than the vacuum method usually applied for this analysis. One determination can be completed in about an hour. The average deviation and standard deviation have been estimated at 0.19 ml/litre heavy water and 0.25 ml/litre heavy water respectively in deuterium, and 0.36 and 0.68 ml/litre in nitrogen. (author)

Carbon and nitrogen determination in Zr by photon or proton activation analysis. Comparison between the results obtained by this method and other analytical techniques

International Nuclear Information System (INIS)

Petit, J.; Gosset, J.; Engelmann, C.

1977-01-01

Carbon and nitrogen are determined by the following nuclear reactions: 12 C(γ,n) 11 C and 14 N(p,α) 11 C. The performances of the method and the main interferences are considered. The process developed for the separation of carbon-11 from zirconium is described and its efficiency evaluated. The results obtained are compared with those given by different laboratories using various analytical techniques [fr

Determination of nitrogen absorption and endogenous nitrogen secretion in the digestive tract of pigs fed with nitrogen-15-labelled dried whey

International Nuclear Information System (INIS)

Gebhardt, G.; Souffrant, W.; Koehler, R.; Zebrowska, T.

1977-01-01

Two fistulated pigs weighing between 15kg and 54kg were given experimental diets containing 15 N-labelled dried whey. The labelled experimental diets were given once only. Samples of the digesta were taken from the duodenum and terminal ileum at various intervals of time up to 48h after feeding the labelled protein feed. The digesta were separated into the four following fractions: Residue on centrifugation, proteins, peptides and free amino acids. The secretion of endogenous nitrogen in the duodenum was 12.5g/24h in pigs having a live weight of 50kg. The endogenous nitrogen was found to be relatively uniformly distributed among the four fractions. The rate of secretion of endogenous nitrogen showed a continuous decrease during 24h. The secretion of endogenous nitrogen in the terminal ileum was 54 to 60mg of nitrogen per kilogram live weight. After passage through the small intestine the greater part of the free amino acids in digesta was of exogenous origin. In the protein fraction most came from endogenous proteins. A true absorption of 17% of nitrogen was determined in the duodenum. The amount of nitrogen absorbed in the terminal part of the small intestine was, on average, 90% relative to the nitrogen intake. The true digestibility calculated with the amount of 15 N in food and faeces was 98%. (author)

Studies on the determination of trace amounts of nitrogen along with alkali and alkaline earth elements in uranium based samples by ion-chromatography (IC)

International Nuclear Information System (INIS)

Verma, Poonam; Rastogi, R.K.; Ramakumar, K.L.

2006-12-01

Present report describes an ion chromatography (IC) method with suppressed conductivity detection for the determination of traces of nitrogen along with alkali and alkaline earth elements in uranium based nuclear fuels. Method was developed to determine nitrogen as NH 4 + along with alkali and alkaline earth cations by IC using a cation exchange column. (author)

Zeolite Soil Application Method Affects Inorganic Nitrogen, Moisture, and Corn Growth

Science.gov (United States)

Adoption of new management techniques which improve soil water storage and soil nitrogen plant availability yet limit nitrogen leaching may help improve environmental quality. A benchtop study was conducted to determine the influence of a single urea fertilizer rate (224 kilograms of Nitrogen per ...

STUDIES OF METHOD FOR DETERMINING THE PROTEIN CONCENTRATION OF "MALEIN PPD" BY THE KJELDAHL METHOD

Directory of Open Access Journals (Sweden)

Ciuca, V

2017-06-01

Full Text Available Glanders is a contagious and fatal disease of horses, donkeys, and mules, caused by infection with the bacterium Burkholderia mallei. The pathogen causes nodules and ulcerations in the upper respiratory tract and lungs. Glanders is transmissible to humans by direct contact with diseased animals or with infected or contaminated material. In the untreated acute disease, the mortality rate can reach 95% within 3 weeks Malein PPD - the diagnostic product contain max 2mg/ml Burkholderia mallei. The amount of protein in the biological product "Malein PPD" is measured as nitrogen from protein molecule, applying the Kjeldahl (method determination of nitrogen by sulphuric acid digestion. The validation study aims to demonstrate the determination of the protein of the Malein PPD, by sulphuric acid digestion, it is an appropriate analytical method, reproducible and meets the quality requirements of diagnostic reagents. The paper establishes the performance characteristics of the method considered and identify the factors that influence these characteristics. The method for determining the concentration of protein, by the Kjeldahl method is considered valid if the results obtained for each validation parameter are within the admissibility criteria.The validation procedure includes details on protocol working to determine the protein of the Malein PPD, validation criteria, experimental results, mathematical calculations.

DETERMINATION OF HEAT TRANSFER COEFFICIENTS FOR FRENCH PLASTIC SEMEN STRAW SUSPENDED IN STATIC NITROGEN VAPOR OVER LIQUID NITROGEN.

Science.gov (United States)

Santo, M V; Sansinena, M; Chirife, J; Zaritzky, N

2015-01-01

The use of mathematical models describing heat transfer during the freezing process is useful for the improvement of cryopreservation protocols. A widespread practice for cryopreservation of spermatozoa of domestic animal species consists of suspending plastic straws in nitrogen vapor before plunging into liquid nitrogen. Knowledge of surface heat transfer coefficient (h) is mandatory for computational modelling; however, h values for nitrogen vapor are not available. In the present study, surface heat transfer coefficients for plastic French straws immersed in nitrogen vapor over liquid nitrogen was determined; vertical and horizontal positions were considered. Heat transfer coefficients were determined from the measurement of time-temperature curves and from numerical solution of heat transfer partial differential equation under transient conditions using finite elements. The h values experimentally obtained for horizontal and vertically placed straws were compared to those calculated using correlations based on the Nusselt number for natural convection. For horizontal straws the average obtained value was h=12.5 ± 1.2 W m(2) K and in the case of vertical straws h=16 ± 2.48 W m(2) K. The numerical simulation validated against experimental measurements, combined with accurate h values provides a reliable tool for the prediction of freezing curves of semen-filled straws immersed in nitrogen vapor. The present study contributes to the understanding of the cryopreservation techniques for sperm freezing based on engineering concepts, improving the cooling protocols and the manipulation of the straws.

Methods of clinical chemistry and isotopic technique for investigation of the nitrogen metabolism in man using 15N

International Nuclear Information System (INIS)

Faust, H.; Bornhak, H.; Hirschberg, K.; Jung, K.; Junghans, P.; Krumbiegel, P.; Reinhardt, R.

1981-03-01

The present manual is a catalogue of methods representing theoretical and practical aspects of application of the stable isotope 15 N in medicine as well as a reference book for users of 15 N techniques in life sciences. Special emphasis is given to the planning of 15 N tracer experiments and their interpretation, sources of error and standard values of nitrogen compounds, information on sampling of medical materials, methods of separation and determination of proteins and non-protein nitrogen compounds in serum and urine, and details of the isotopic analysis of nitrogen by emission and mass spectrometry. (author)

Spectrometric determination of ammonium-nitrogen with quinol in ...

African Journals Online (AJOL)

Quinol is proposed as a reagent for the spectrometric determination of ammonium-nitrogen (NH4+-N) in aqueous medium. Quinol forms a pink complex with ammonium salt in aqueous medium. Hydrogen peroxide is needed for colour accentuation. The quinol/ammonium charge transfer complex has absorption maximum ...

Blank evaluation in nitrogen determination in seed grains by 14 MeV neutron activation analysis

International Nuclear Information System (INIS)

Wasek, M.; Sterlinski, S.

1987-01-01

In this work the term 'blank' signifies total radiation of the sample analyzed except that the element to be determined (analyte) is absent. On the basis of the evaluation of the blank components (nuclear and spectral interferences, air-nitrogen between grains, etc.), a semiempirical formula for calculating the nitrogen content in plant grain samples is proposed. The reliability of the results obtained with the use of this formula was demonstrated for five sorts of seeds (rye, wheat, barley, broad bean and soybean) which were analyzed by the Kjeldahl method and 14 MeV neutron activation analysis, respectively. (author)

The effect of the rate and method of nitrogen application on nitrogen uptake and utilization by broccoli (Brassica oleracea var. italica)

NARCIS (Netherlands)

Everaarts, A.P.; Willigen, de P.

1999-01-01

The effect of the rate and method of nitrogen application on nitrogen uptake and utilization by broccoli (Brassica oleracea var. italica) was studied in four field experiments. The methods of application were broadcast application vs band placement and split application. Maximum uptake of nitrogen

Simulation methods of rocket fuel refrigerating with liquid nitrogen and intermediate heat carrier

Directory of Open Access Journals (Sweden)

O. E. Denisov

2014-01-01

Full Text Available Temperature preparation of liquid propellant components (LPC before fueling the tanks of rocket and space technology is the one of the operations performed by ground technological complexes on cosmodromes. Refrigeration of high-boiling LPC is needed to increase its density and to create cold reserve for compensation of heat flows existing during fueling and prelaunch operations of space rockets.The method and results of simulation of LPC refrigeration in the recuperative heat exchangers with heat carrier which is refrigerated by-turn with liquid nitrogen sparging. The refrigerating system consists of two tanks (for the chilled coolant and LPC, LPC and heat carrier circulation loops with heat exchanger and system of heat carrier refrigeration in its tank with bubbler. Application of intermediate heat carrier between LPC and liquid nitrogen allows to avoid LPC crystallization on cold surfaces of the heat exchanger.Simulation of such systems performance is necessary to determine its basic design and functional parameters ensuring effective refrigerating of liquid propellant components, time and the amount of liquid nitrogen spent on refrigeration operation. Creating a simulator is quite complicated because of the need to take into consideration many different heat exchange processes occurring in the system. Also, to determine the influence of various parameters on occurring processes it is necessary to take into consideration the dependence of all heat exchange parameters on each other: heat emission coefficients, heat transfer coefficients, heat flow amounts, etc.The paper offers an overview of 10 references to foreign and Russian publications on separate issues and processes occurring in liquids refrigerating, including LPC refrigeration with liquid nitrogen. Concluded the need to define the LPC refrigerating conditions to minimize cost of liquid nitrogen. The experimental data presented in these publications is conformed with the application of

Determination of ifosfamide, 2-and 3-dechloroethyifosfamide using gas chromatography with nitrogen-phosphorus or mass spectrometry detection

NARCIS (Netherlands)

Kerbusch, T; Jeuken, MJ; Derraz, J; van Putten, JWG; Huitema, ADR; Beijnen, JH

2000-01-01

A comparison was made between methods for determining ifosfamide (IF), 2- (2DCE) and 3-dechloroethylifosfamide (3DCE) using gas chromatography with nitrogen-phosphorus detection (GC-NPD) versus positive ion electron-impact ion-trap mass spectrometry (GC-MS'). Sample pretreatment involved

Contribution to the simultaneous determination of several light elements in alkalin metals by gamma photon and charged particle activation. Application to carbon and nitrogen determination in sodium

International Nuclear Information System (INIS)

Bock, Patrice.

1976-10-01

A new γ activation method for the simultaneous determination of carbon and nitrogen in sodium is described. It makes use of the nuclear reactions: 12 C(γ,n) 11 C and 14 N(γ,n) 13 N. The process used to separate carbone-11 and nitrogen-13 from sodium with a view to their radio-activity determination is based on vacuum dissolution of the sample in a mixture of oxidizing and acid fused salts. The oxidized carbon is trapped as CO 2 on soda asbestos and the nitrogen as N 2 on molecular sieve at -196 deg C. The efficiency of the technique is estimated by means of tracer tests and by proton activation. The relative influence of competitive nuclear reactions on elements close to the above two impurities, or even on the matrix itself, is examined. The method described has a theoretical detection limit of some 10 -8 g.g -1 for the two elements in question and mean concentrations of 0.3+-0.1x10 -6 g.g -1 carbon and 1.0+-0.5x10 -6 g.g -1 nitrogen have in fact been measured in a batch of 0.5 g sodium samples [fr

Determination of nitrogen in UO2 pellets by hot extraction-TCD method without using flux material and evaluation of associated measurement uncertainties

International Nuclear Information System (INIS)

Begum, Zahida; Balaji Rao, Y.; Subba Rao, Y.

2015-01-01

Presence of non metallic impurity elements like nitrogen above the specified limit of 75 ppm (max.) in fuel pellets affects the sintered density of fuel and also effect the Zircaloy fuel clad by forming brittle nitride phase. Hence, estimation of nitrogen plays an important role in qualifying the fuel material. Conventionally, Kjeldahl steam distillation followed by UV-Visible Spectro-photometric method has been widely employed for the estimation of nitrogen in UO 2 pellets. However, inherent chemical treatment processes causes the blank variations and provides the scope for uncertainty in measurements apart from being time consuming method. This makes Kjeldahl method as an un-attractive choice for any industrial lab where high analytical loads usually exist to meet the production targets and also where urgency for quick analytical feedback is an issue. In view of this, a simple, rapid and reliable method using A LECO Model TN- 600 Nitrogen analyzer based on Hot Extraction (HT) without adding any flux material followed by Thermal Conductivity Detection (TCD) has been developed for routine analysis. Several flux materials like Pt or Ni are used to bring down the temperature of extraction due to formation of stable uranium nitrides and temperatures of 2500°C is maintained for quantitative extraction. However usage of flux materials leads to several practical problems in analysis like deposition of uranium carbide dust onto the upper electrode requiring tedious cleaning and even sometimes causing the breakage of crucibles during the analysis. Thus an attempt has been made to increase the temperatures closer to 3000°C without using flux. Working temperature of 2900°C was arrived by plotting quantity of nitrogen extracted with temperature of extraction and flattening of plot took place at 2900°C

Flow analysis methods for the direct ultra-violet spectrophotometric measurement of nitrate and total nitrogen in freshwaters

Energy Technology Data Exchange (ETDEWEB)

Gentle, Brady S.; Ellis, Peter S.; Grace, Michael R. [Water Studies Centre, School of Chemistry, Monash University, Victoria 3800 (Australia); McKelvie, Ian D., E-mail: iandm@unimelb.edu.au [School of Chemistry, University of Melbourne, Victoria 3010 (Australia); School of Geography, Earth and Environmental Sciences, University of Plymouth, Drake Circus, Plymouth PL4 8AA (United Kingdom)

2011-10-17

Highlights: {yields} Second derivative UV spectrophotometry has been used to determine nitrate and total N using flow analysis techniques. {yields} A simple flow system with a single-reflection flow-through cell was used for the UV measurement of nitrate. {yields} Total N was determined after on-line UV photooxidation with alkaline peroxodisulfate. {yields} Analyses carried out using the developed flow systems show a high degree of agreement with comparative analyses. {yields} This method requires no colorimetric reagents and eliminates the requirement for a toxic cadmium reduction column. - Abstract: Second derivative ultra-violet spectrophotometric methods are described for the measurement of nitrate and total nitrogen in freshwaters using flow analysis techniques. A simple flow system consisting of a peristaltic pump and a single-reflection flow-through cell was used for the measurement of nitrate. Quantification of total nitrogen using alkaline peroxodisulfate photo-digestion was achieved by incorporating an ultra-violet photo-reactor, a hollow-fibre filter and a debubbler into the flow system. The nitrate system featured a limit of detection of 0.04 mg N L{sup -1}, 0.4%RSD (1 mg N L{sup -1} as nitrate, n = 10), a coefficient of determination (R{sup 2}) of 0.9995 over the calibration range 0.0-2.0 mg N L{sup -1}, and a data acquisition time of 1.5 s per spectrum. The total nitrogen system featured a limit of detection of 0.05 mg N L{sup -1}, 1%RSD (1 mg N L{sup -1} as ammonium chloride, n = 10), a coefficient of determination of 0.9989 over the calibration range 0.0-2.0 mg N L{sup -1}, and a throughput of 5 sample h{sup -1} measured in triplicate. Digestions of five model nitrogen compounds returned recoveries of >88%. Determinations carried out using the developed systems show a high degree of agreement with data obtained using reference methods. These methods require no colorimetric reagents and eliminate the requirement for a toxic cadmium reduction column

Flow analysis methods for the direct ultra-violet spectrophotometric measurement of nitrate and total nitrogen in freshwaters

International Nuclear Information System (INIS)

Gentle, Brady S.; Ellis, Peter S.; Grace, Michael R.; McKelvie, Ian D.

2011-01-01

Highlights: → Second derivative UV spectrophotometry has been used to determine nitrate and total N using flow analysis techniques. → A simple flow system with a single-reflection flow-through cell was used for the UV measurement of nitrate. → Total N was determined after on-line UV photooxidation with alkaline peroxodisulfate. → Analyses carried out using the developed flow systems show a high degree of agreement with comparative analyses. → This method requires no colorimetric reagents and eliminates the requirement for a toxic cadmium reduction column. - Abstract: Second derivative ultra-violet spectrophotometric methods are described for the measurement of nitrate and total nitrogen in freshwaters using flow analysis techniques. A simple flow system consisting of a peristaltic pump and a single-reflection flow-through cell was used for the measurement of nitrate. Quantification of total nitrogen using alkaline peroxodisulfate photo-digestion was achieved by incorporating an ultra-violet photo-reactor, a hollow-fibre filter and a debubbler into the flow system. The nitrate system featured a limit of detection of 0.04 mg N L -1 , 0.4%RSD (1 mg N L -1 as nitrate, n = 10), a coefficient of determination (R 2 ) of 0.9995 over the calibration range 0.0-2.0 mg N L -1 , and a data acquisition time of 1.5 s per spectrum. The total nitrogen system featured a limit of detection of 0.05 mg N L -1 , 1%RSD (1 mg N L -1 as ammonium chloride, n = 10), a coefficient of determination of 0.9989 over the calibration range 0.0-2.0 mg N L -1 , and a throughput of 5 sample h -1 measured in triplicate. Digestions of five model nitrogen compounds returned recoveries of >88%. Determinations carried out using the developed systems show a high degree of agreement with data obtained using reference methods. These methods require no colorimetric reagents and eliminate the requirement for a toxic cadmium reduction column. The overlap of chloride and nitrate spectra in seawater is

Distribution of nitrogen in nature and its separation

International Nuclear Information System (INIS)

Nitzsche, H.M.; Haendel, D.; Muehle, K.

1981-01-01

Proceeding from a survey on nitrogen in the atmosphere, biosphere, hydrosphere, and lithosphere and nitrogen determination methods, a detailed review is given of procedures that allow to transform any nitrogen-containing starting material into molecular nitrogen for mass spectroscopic isotope analysis

Determination of the ''1''4N to ''1''5N ratio in nitrogen-containing samples

International Nuclear Information System (INIS)

Aidarhanova, G.; Baktybaev, D.T.; Burtebaeva, N.; Burtebaev, N.; Djazairov-Kakhramanov, V.; Zazulin, D.M.; Urazaliev, R.U.; Ramazanova, S.B.; Baimaganova, G.Sh.; Ramazanova, R.H.

2001-01-01

It is known that nitrogen nutrition plays very important role in increase of plant crop and the albumin content in food rural cultures. Producers widely use nitrogen fertilizers. Their non-controlled or too extensive use can lead to contamination of air and water , resulting in hazardous sequences for human health and environment. The studies related to determination of nitrogen nutrition efficiency are based on utilization of the ''1''5N isotope, in view of determination of the best forms, time and place for introduction of nitrogen fertilizers, in order to provide the most reasonable nitrogen consumption by plants, avoiding waste and reducing the nitrogen fertilizer volumes required for obtaining a desired level of crop. In the course of natural experiments, scientists of various countries studied the processes of nitrogen consumption by plants from fertilizers, the processes responsible for nitrogen fixing in soil, nitrogen losses in a gaseous form or in liquids, in a form of solutions with ground water. The studies have shown that a fresh organic mass (manure) introduced to soil causes acceleration of decomposition of organic substance and renewal of the humus composition in soil. These phenomena can be detected by means of radioactive or stable isotopes

Application of titration methods for measuring the contents of ammonium nitrogen and volatile fatty acids in agricultural biogas plants.

Science.gov (United States)

Piątek, Michał; Lisowski, Aleksander; Lisowska, Barbara

2017-12-20

The aim of our research was to assess a relatively new method of estimating ammonium nitrogen concentration in anaerobic digestion of plant substrates. We analysed our own data, received from the anaerobic digestion of maize silage (PM), as well as data published by Purser et al. (2014) who measured energy crops and slurry (ECS), and food waste (FW). In our study, the process was monitored for VFA content that was determined by gas chromatography, and for the content of ammonium nitrogen determined using the HACH LANGE LCK 303 cuvette test. We created polynomial regression models that bind the content of ammonium nitrogen with the volume of H 2 SO 4 used to titrate the sample from initial pH to pH 5. To estimate parameters of model, the PM dataset was used. The obtained models were positively validated using ECS and FW datasets. Our results confirmed the effectiveness of the Purser et al. method with an average absolute error of less than 223mgl -1 of the VFA concentration, which was approximately 20-times less than the level that caused inhibition. In conclusion, we can affirm the suitability of using titration methods to assess the ammonium nitrogen content of bioreactors with a stable composition. Copyright © 2017 Elsevier B.V. All rights reserved.

Method of removing nitrogen monoxide from a nitrogen monoxide-containing gas using a water-soluble iron ion-dithiocarbamate, xanthate or thioxanthate

Science.gov (United States)

Liu, D. Kwok-Keung; Chang, Shih-Ger

1987-08-25

The present invention relates to a method of removing of nitrogen monoxide from a nitrogen monoxide-containing gas which method comprises contacting a nitrogen oxide-containing gas with an aqueous solution of water soluble organic compound-iron ion chelate complex. The NO absorption efficiency of ferrous urea-dithiocarbamate and ferrous diethanolamine-xanthate as a function of time, oxygen content and solution ph is presented. 3 figs., 1 tab.

Method for determining the concentration of adsorbed protein and cell biomass in cellulose fermentations

Energy Technology Data Exchange (ETDEWEB)

Moreira, A R; Phillips, J A; Humphrey, A E

1978-09-01

The method presented is based on the determination of the total Lowry protein of the solids and the total Kjeldahl nitrogen of the solids. Experimental data proving the validity of the method are reported. (JSR)

Nitrogen-Doped Carbon Dots as A New Substrate for Sensitive Glucose Determination

Directory of Open Access Journals (Sweden)

Hanxu Ji

2016-05-01

Full Text Available Nitrogen-doped carbon dots are introduced as a novel substrate suitable for enzyme immobilization in electrochemical detection metods. Nitrogen-doped carbon dots are easily synthesised from polyacrylamide in just one step. With the help of the amino group on chitosan, glucose oxidase is immobilized on nitrogen-doped carbon dots-modified carbon glassy electrodes by amino-carboxyl reactions. The nitrogen-induced charge delocalization at nitrogen-doped carbon dots can enhance the electrocatalytic activity toward the reduction of O2. The specific amino-carboxyl reaction provides strong and stable immobilization of GOx on electrodes. The developed biosensor responds efficiently to the presence of glucose in serum samples over the concentration range from 1 to 12 mM with a detection limit of 0.25 mM. This novel biosensor has good reproducibility and stability, and is highly selective for glucose determination under physiological conditions. These results indicate that N-doped quantum dots represent a novel candidate material for the construction of electrochemical biosensors.

Signatures of nitrogen stable isotope and determination of organic food authentication

International Nuclear Information System (INIS)

Yuan Yuwei; Zhang Zhiheng; Yang Guiling; Wang Qiang

2009-01-01

Chemical fertilizers were not permitted to be applied in organic agricultural production, so fertilizer as one of agricultural inputs is an important regulatory aspect in the organic food accreditation. Natural stable isotope abundances δ 15 N from different nitrogenous fertilizers are different, the same as in the agricultural products. Natural abundances δ 15 N in the agricultural products using organic fertilizer is higher than those in the products without using any fertilizer, while it is the lowest in the products using chemical nitrogenous fertilizer. Natural abundances δ 15 N are also affected by the ways of fertilizer treatment, the types of the crops and the growth stages as well as the different parts of crops. Generally, natural abundances of δ 15 N are preferred to trace nitrogenous fertilizer for the vegetables with shorter growing period, but not for the crops with longer growing period or nitrogen fixation. The techniques to trace the nitrogen abundances of δ 15 N in the crops play a positive role, which is useful for the determination of organic food authentication, perfecting the system of quality and supervision and protecting public health, therefore it has a theoretical and applied value. (authors)

Nitrogen in Chinese coals

Science.gov (United States)

Wu, D.; Lei, J.; Zheng, B.; Tang, X.; Wang, M.; Hu, Jiawen; Li, S.; Wang, B.; Finkelman, R.B.

2011-01-01

Three hundred and six coal samples were taken from main coal mines of twenty-six provinces, autonomous regions, and municipalities in China, according to the resource distribution and coal-forming periods as well as the coal ranks and coal yields. Nitrogen was determined by using the Kjeldahl method at U. S. Geological Survey (USGS), which exhibit a normal frequency distribution. The nitrogen contents of over 90% Chinese coal vary from 0.52% to 1.41% and the average nitrogen content is recommended to be 0.98%. Nitrogen in coal exists primarily in organic form. There is a slight positive relationship between nitrogen content and coal ranking. ?? 2011 Science Press, Institute of Geochemistry, CAS and Springer Berlin Heidelberg.

Molecular nitrogen fixation and nitrogen cycle in nature

Energy Technology Data Exchange (ETDEWEB)

Virtanen, A I

1952-01-01

The origin of nitrogen oxides in the atmosphere is discussed. Evidently only a small proportion of the nitrate-and nitrite-nitrogen found in the precipitation is formed through electric discharges from molecular nitrogen, photochemical nitrogen fixation being probably of greater importance. Formation of nitrate nitrogen through atmospheric oxidation of nitrous oxide (N/sub 2/O) evaporating from the soil is also considered likely. Determination of nitrogen compounds at different altitudes is indispensable for gaining information of the N/sub 2/-fixation in the atmosphere and, in general, of the origin of nitrogen oxides and their decomposition. International cooperation is needed for this as well as for the quantitative determination of the nitrogen compounds removed from the soil by leaching and brought by waters into the seas.

Nitrogen determination in pepper (Capsicum frutescens L.) plants by ...

African Journals Online (AJOL)

use

2011-12-05

Dec 5, 2011 ... significant negative relations between G/(R+G+B) ratio of coverage image and the indexes of pepper nitrogen status in this experiment. Hence, the suitable index of assessing pepper N status by color image analysis was discussed. MATERIALS AND METHODS. Experimental design. Experiment was made ...

Determination of atmospheric nitrogen dioxide by sampling with impregnated filters

International Nuclear Information System (INIS)

Galiano, J.A.; Palomares, F.

1978-01-01

The performance of filters impregnated with triethanolamine for the collection and subsequent determination of atmospheric nitrogen dioxide is studied taking into account the influence of several parameters: storage of filters, reagents, elapsed time, sampling efficiency, etc. The results obtained for sampling times of 24 hours are satisfactory. (author) [es

Determination of biological nitrogen fixation capacities of winter and spring lentil varieties by using ''1''5N methodology

International Nuclear Information System (INIS)

Akin, A.

2001-01-01

In order to determine the biological nitrogen fixation capacities of winter and spring varieties of lentil which have of agronomic importance under the Central Anatolia region, the field experiments (winter and spring) were carried out. In both experiments, the effects of two different iconoclasts and different harvesting times on the biological nitrogen fixation capacities of lentil varieties, were investigated. The field experiments were conducted using by randomized block design as split-split plot for 4 replications. Barley was selected as the reference crop and 20 cm row spacing were used for lentil and barley. Inoculations were done immediately before sowing. 10.0 kg N/ ha for lentil varieties as 10.0 % ''1''5N atom excess and 40.0 kg N/ ha for barley (reference crop) as 2.0 % ''1''5N atom excess ammonium sulphate fertilizer were applied. In addition, 60.0 kgP 2 O 5 / ha were applied as triple superphosphate for all treatments. Plants were harvested at the different growth stages and than plant materials prepared for the analysis. Total nitrogen and % ''1''5N atom excess analysis were done by Kjeldahl method and Emission spectrometer, respectively. The amount of nitrogen fixation capacities of winter and spring lentil varieties were calculated according to the A-Value method (IAEA 1990). The results showed us that the winter varieties of lentil had higher dry matter yields and nitrogen fixation capacities than the spring varieties. Inoculation treatments had no statistically significant effects on the percentage of nitrogen derived from atmosphere (% Ndfa) and the amount of fixed nitrogen (kg N/ ha) for both experiments. In comparison between the harvesting times, the highest amount of fixed nitrogen was found at the pod formation stage for all cultivars. The average amounts of % Ndfa and fixed nitrogen (kg N/ ha) were 75.0 and 70.0 for winter cultivars, 70.0 and 45.0 for spring cultivars, respectively

A calorimetric method to determine water activity.

Science.gov (United States)

Björklund, Sebastian; Wadsö, Lars

2011-11-01

A calorimetric method to determine water activity covering the full range of the water activity scale is presented. A dry stream of nitrogen gas is passed either over the solution whose activity should be determined or left dry before it is saturated by bubbling through water in an isothermal calorimeter. The unknown activity is in principle determined by comparing the thermal power of vaporization related to the gas stream with unknown activity to that with zero activity. Except for three minor corrections (for pressure drop, non-perfect humidification, and evaporative cooling) the unknown water activity is calculated solely based on the water activity end-points zero and unity. Thus, there is no need for calibration with references with known water activities. The method has been evaluated at 30 °C by measuring the water activity of seven aqueous sodium chloride solutions ranging from 0.1 mol kg(-1) to 3 mol kg(-1) and seven saturated aqueous salt solutions (LiCl, MgCl(2), NaBr, NaCl, KCl, KNO(3), and K(2)SO(4)) with known water activities. The performance of the method was adequate over the complete water activity scale. At high water activities the performance was excellent, which is encouraging as many other methods used for water activity determination have limited performance at high water activities. © 2011 American Institute of Physics

Assessing total nitrogen in surface-water samples--precision and bias of analytical and computational methods

Science.gov (United States)

Rus, David L.; Patton, Charles J.; Mueller, David K.; Crawford, Charles G.

2013-01-01

The characterization of total-nitrogen (TN) concentrations is an important component of many surface-water-quality programs. However, three widely used methods for the determination of total nitrogen—(1) derived from the alkaline-persulfate digestion of whole-water samples (TN-A); (2) calculated as the sum of total Kjeldahl nitrogen and dissolved nitrate plus nitrite (TN-K); and (3) calculated as the sum of dissolved nitrogen and particulate nitrogen (TN-C)—all include inherent limitations. A digestion process is intended to convert multiple species of nitrogen that are present in the sample into one measureable species, but this process may introduce bias. TN-A results can be negatively biased in the presence of suspended sediment, and TN-K data can be positively biased in the presence of elevated nitrate because some nitrate is reduced to ammonia and is therefore counted twice in the computation of total nitrogen. Furthermore, TN-C may not be subject to bias but is comparatively imprecise. In this study, the effects of suspended-sediment and nitrate concentrations on the performance of these TN methods were assessed using synthetic samples developed in a laboratory as well as a series of stream samples. A 2007 laboratory experiment measured TN-A and TN-K in nutrient-fortified solutions that had been mixed with varying amounts of sediment-reference materials. This experiment identified a connection between suspended sediment and negative bias in TN-A and detected positive bias in TN-K in the presence of elevated nitrate. A 2009–10 synoptic-field study used samples from 77 stream-sampling sites to confirm that these biases were present in the field samples and evaluated the precision and bias of TN methods. The precision of TN-C and TN-K depended on the precision and relative amounts of the TN-component species used in their respective TN computations. Particulate nitrogen had an average variability (as determined by the relative standard deviation) of 13

Non-destructive determination of nitrogen in malting barleys by instrumental photon activation analysis and its comparison with the Dumas method

Czech Academy of Sciences Publication Activity Database

Krausová, Ivana; Mizera, Jiří; Dostálek, P.; Řanda, Zdeněk

2018-01-01

Roč. 124, č. 1 (2018), s. 4-8 ISSN 0046-9750 R&D Projects: GA ČR(CZ) GBP108/12/G108 Institutional support: RVO:61389005 Keywords : nitrogen * instrumental photon activation analysis * Dumas method * malting barley Subject RIV: GM - Food Processing OBOR OECD: Food and beverages Impact factor: 0.859, year: 2016

Control of the nitrogen concentration in liquid lithium by the hot trap method

International Nuclear Information System (INIS)

Sakurai, Toshiharu; Yoneoka, Toshiaki; Tanaka, Satoru; Suzuki, Akihiro; Muroga, Takeo

2002-01-01

The nitrogen concentration in liquid lithium was controlled by the hot-trap method. Titanium, vanadium and a V-Ti alloy were used as nitrogen gettering materials. Gettering experiments were conducted at 673, 773 and 823 K for 0.4-2.8 Ms. After immersion, the nitrogen concentration increased in titanium and V-Ti were tested at 823 K. Especially the nitrogen gettering effect by the V-10at.%Ti alloy was found to be large. Nitrogen was considered to exist mainly as solid solution in the V-10at.%Ti alloy. The decrease of the nitrogen concentration in liquid lithium by the V-Ti gettering was also confirmed

Determination of nitrogen in wheat flour through Activation analysis using Fast neutron flux of a Thermal nuclear reactor

International Nuclear Information System (INIS)

Ramirez G, T.

1976-01-01

In this work is done a technical study for determining Nitrogen (protein) and other elements in wheat flour Activation analysis, with Fast neutrons from a Thermal nuclear reactor. Initially it is given an introduction about the basic principles of the methods of analysis. Equipment used in Activation analysis and a brief description of the neutron source (Thermal nuclear reactor). The realized experiments for determining the flux form in the irradiation site, the half life of N-13 and the interferences due to the sample composition are included too. Finally, the obtained results by Activation and the Kjeldahl method are tabulated. (Author)

On nitrogen condensation in hypersonic nozzle flows: Numerical method and parametric study

KAUST Repository

Lin, Longyuan

2013-12-17

A numerical method for calculating two-dimensional planar and axisymmetric hypersonic nozzle flows with nitrogen condensation is developed. The classical nucleation theory with an empirical correction function and the modified Gyarmathy model are used to describe the nucleation rate and the droplet growth, respectively. The conservation of the liquid phase is described by a finite number of moments of the size distribution function. The moment equations are then combined with the Euler equations and are solved by the finite-volume method. The numerical method is first validated by comparing its prediction with experimental results from the literature. The effects of nitrogen condensation on hypersonic nozzle flows are then numerically examined. The parameters at the nozzle exit under the conditions of condensation and no-condensation are evaluated. For the condensation case, the static pressure, the static temperature, and the amount of condensed fluid at the nozzle exit decrease with the increase of the total temperature. Compared with the no-condensation case, both the static pressure and temperature at the nozzle exit increase, and the Mach number decreases due to the nitrogen condensation. It is also indicated that preheating the nitrogen gas is necessary to avoid the nitrogen condensation even for a hypersonic nozzle with a Mach number of 5 operating at room temperatures. © 2013 Springer-Verlag Berlin Heidelberg.

Uptake of fertilizer nitrogen and soil nitrogen by rice using 15N-labelled nitrogen fertilizer

International Nuclear Information System (INIS)

Reddy, K.R.; Patrick, W.H. Jr.

1980-01-01

Data from five field experiments using labelled nitrogen fertilizer were used to determine the relative effects of soil nitrogen and fertilizer nitrogen on rice yield. Yield of grain was closely correlated with total aboveground nitrogen uptake (soil + fertilizer), less closely correlated with soil nitrogen uptake and not significantly correlated with fertilizer nitrogen uptake. When yield increase rather than yield was correlated with fertilizer nitrogen uptake, the correlation coefficient was statistically significant. (orig.)

Effects of nitrogen application method and weed control on corn yield and yield components.

Science.gov (United States)

Sepahvand, Pariya; Sajedi, Nurali; Mousavi, Seyed Karim; Ghiasvand, Mohsen

2014-04-01

The effects of nitrogen fertilizer application and different methods for weed control on yield and yield components of corn was evaluated in Khorramabad in 2011. The experiment was conducted as a split plot based on randomized complete block design in 3 replications. Nitrogen application was as main plot in 4 levels (no nitrogen, broadcasting nitrogen, banding nitrogen and sprayed nitrogen) and methods of weed control were in 4 levels (non-control weeds, application Equip herbicide, once hand control of weeds and application Equip herbicide+once time weeding) was as subplots. Result illustrated that effects of nitrogen fertilizer application were significant on grain and forage yield, 100 seeds weight, harvest index, grain number per row and cob weight per plant. Grain yield increased by 91.4 and 3.9% in application banding and broadcasting for nitrogen fertilizer, respectively, compared to the no fertilizer treatment. The results show improved efficiency of nitrogen utilization by banding application. Grain yield, harvest index, seed rows per cob, seeds per row and cob weight were increased by weed control. In the application of Equip herbicide+ hand weeding treatment corn grain yield was increased 126% in comparison to weedy control. It represents of the intense affects of weed competition with corn. The highest corn grain yield (6758 kg h(-1)) was related to the application banding of nitrogen fertilizer and Equip herbicide+once hand weeding.

Nitrogen and protein contents in some aquatic plant species

Directory of Open Access Journals (Sweden)

Krystyna Bytniewska

2015-01-01

Full Text Available Nitrogen and protein contents in higher aquatic plants deriving from a natural habitat were determined. The following plants were examined: Spirodela polyrrhiza (L. Schleid., Elodea canadensis Rich., Riccia fluitans L. Total nitrogen and nitrogen of respective fractions were determined by the Kjeldahl method. Nitrogen compounds were fractionated according to Thimann et al. Protein was extracted after Fletcher and Osborne and fractionated after Osborne. It was found, that total protein content in the plants under examination constitutes 18 to 25%o of dry matter. Albumins and glutelins are the most abundant protein fractions.

Nitrogen determination in wheat by neutron activation analysis using fast neutron flux from a thermal nuclear reactor

International Nuclear Information System (INIS)

Ramirez G, T.

1976-01-01

This is a study of the technique for the determination of nitrogen and other elements in wheat flour through activation analysis with fast neutrons from a thermal nuclear reactor. The study begins with an introduction about the basis of the analytical methods, the equipment used in activation analysis and a brief description of the neutrons source. In the study are included the experiments carried out in order to determine the flux form in the site of irradiation, the N-13 half life and the interference due to the sample composition. (author)

Nitrogen studies for achieving the whole-year harvest

International Nuclear Information System (INIS)

Boven, G.D.; Danso, K.A.

1987-01-01

The IAEA activity in solving the problems related to recovery of productivity of soils subjected to erosion in tropical regions using nitrogen-fixator plants which include pasture bean crops and trees, is considered. The IAEA activity covers development of appropriate methods of changing fixed nitrogen in perennial plants, determination of practical ways of increasing nitrogen fixation and development of reliable and high-productivity systems of bean-herb pastures. The main attention is paid to methods of farming and selection. Favourable effect of forest planting on recovery and preservation of soil productivity and important role of isotopic and nuclear methods (using 15 N) in care for trees and nitrogen fixation improvement are underlined

Review of methods for determination of ammonia volatilization in farmland

Science.gov (United States)

Yang, J.; Jiao, Y.; Yang, W. Z.; Gu, P.; Bai, S. G.; Liu, L. J.

2018-02-01

Ammonia is one of the most abundant alkaline trace gases in the atmosphere, which is one of the important factors affecting atmospheric quality. Excessive application of nitrogen fertilizer is the main source of global ammonia emissions, which not only exacerbate greenhouse gas emissions, but also leads to eutrophication of water bodies. In this paper, the basic principle, the operation process, the advantages and disadvantages, and the previous research results of the method are summarized in detail, including the enclosure method, the venting method, the continuous airflow enclosure method, the wind tunnel method and the micro-meteorological method. So as to provide a theoretical basis for selecting the appropriate method for determination of ammonia volatilization.

[Simultaneous determination of four common nonprotein nitrogen substances in urine by high performance liquid chromatography].

Science.gov (United States)

Ma, Yuhua; Huang, Dongqun; Zhang, Rui; Xu, Shiru; Feng, Shun

2013-11-01

A high performance liquid chromatographic (HPLC) method was proposed to simultaneously determine four common nonprotein nitrogen substances, including creatine (Cr), creatinine (Cn), uric acid (Ua) and pseudouridine (Pu) in urine. After proteins being removed by acetone precipitation method, freeze drying and redissolving, the urine samples were analyzed by HPLC. Chromatographic separation was performed on a Waters RP18 Column (150 mm x 4.60 mm, 3.5 microm) in gradient elution mode using 10.0 mmol/L KH2PO4 solution (pH 4.78) and acetonitrile as mobile phases at a flow rate of 0.8 mL/min. The samples were detected at 220 nm. Rapid separation was achieved within 7 min. Under the optimized conditions, good linearities of four common nonprotein nitrogen substances were obtained in the range of 0.1-250 mg/L. The detection limits were 9.31 (Cr), 26.19 (Cn), 4.70 (Ua), an 6.30 (Pu) microg/L and the recoveries were in the range of 81%-111% with the relative standar deviations of 0.23%-2.78% (n = 3). The results demonstrate that this method is simple, rapid and accurate with good reproducibility, and can provide early diagnosis and preliminary judgment for type 2 diabetes mellitus (T2DM) patients with renal damage.

Method for combined removal of mercury and nitrogen oxides from off-gas streams

Science.gov (United States)

Mendelsohn, Marshall H [Downers Grove, IL; Livengood, C David [Lockport, IL

2006-10-10

A method for removing elemental Hg and nitric oxide simultaneously from a gas stream is provided whereby the gas stream is reacted with gaseous chlorinated compound to convert the elemental mercury to soluble mercury compounds and the nitric oxide to nitrogen dioxide. The method works to remove either mercury or nitrogen oxide in the absence or presence of each other.

Root distribution pattern and nitrogen uptake of some wheat and triticale germplasms in relation to rates and methods of nitrogen application

International Nuclear Information System (INIS)

Meena, N.L.; Seth, Jagdish

1975-01-01

A field experiment was conducted under irrigated conditions with four germplasms viz. Triticale(70-2), and wheat varieties HD 4502(durum), Kalyan Sona and Moti (aestivums) at the Indian Agricultural Research Institute Farm, New Delhi, during rabi season of 1972-73. The treatments comprised of three rates of nitrogen viz. 0,60 and 120 kg/ha and two methods of nitrogen application viz. (1) soil + foliar and (2) soil. The root distribution of the four germplasms, studied by 32 P injection technique was increased both vertically and horizontally with the addition of nitrogen. Root distribution of triticale was observed to be deep and spreading in habit, while durum proved to be shallow rooted and compact in nature. The total uptake of nitrogen was significantly increased with higher rates of nitrogen in all the germplasms. The maximum uptake of nitrogen was observed in the durum wheat. (author)

Glove box adaptation of oxygen, nitrogen and hydrogen determinator

International Nuclear Information System (INIS)

Ramanjaneyulu, P.S.; Phanindra Kumar, M.; Kulkarni, A.S.; Revathi, R.; Saxena, M.K.; Tomar, B.S.

2017-01-01

Radioanalytical Chemistry Division (RACD) is involved in chemical quality assurance (CQA) of various nuclear fuels and materials related to various DAE projects including FBTR and PFBR. Determination of oxygen, nitrogen and hydrogen in these fuels is one of the important steps in the CQA of material. For this purpose, O, N and H determinator was indigenously designed, fabricated and commissioned with the help of M/s Chromatography and Instruments Company Ltd., Vadodara, India. The present article describes about glove box adaptation of this instrument and various safety features incorporated in the glove box and instrument at Lab. C-25, RACD, as per the recommendations of the plant level safety committee

Measurement of nitrogen dioxide in the air

Energy Technology Data Exchange (ETDEWEB)

Monteriolo, S C; Bertolaccini, M A

1973-01-01

A comparative study of automatic analytical methods for the monitoring of nitric oxide and nitrogen dioxide in the air indicates the need for a correct chemical conversion of the nonmeasurable species into the measurable species to obtain dependable results. The automatic colorimetric and chemiluminescent methods were compared to the manual colorimeter, and the electrochemical method was compared to chemiluminescence. Average, minimum, and maximum values are given for each comparison. All three methods are equally valid, in response linearity, sensitivity, and concentration limit, for the determination of nitric oxide, the measurable species. The determination of nitrogen dioxide, however, is strictly dependent on the efficiency of the conversion of the non-measurable species into the measurable form.

Performance evaluation of nitrogen isotope ratio determination in marine and lacustrine sediments: An inter-laboratory comparison

NARCIS (Netherlands)

Bahlmann, E.; Bernasconi, S.M.; Bouillon, S.; Houtekamer, M.J.; Korntheuer, M.; Langenberg, F.; Mayr, C.; Metzke, M.; Middelburg, J.J.; Nagel, B.; Struck, U.; Voß, M.; Emeis, K.C.

2010-01-01

Nitrogen isotopes of organic matter are increasingly studied in marine biogeochemistry and geology, plant and animal ecology, and paleoceanography. Here, we present results of an inter-laboratory test on determination of nitrogen isotope ratios in marine and lacustrine sediments. Six different

Conductometric titration to determine total volatile basic nitrogen (TVB-N) for post-mortem interval (PMI).

Science.gov (United States)

Xia, Zhiyuan; Zhai, Xiandun; Liu, Beibei; Mo, Yaonan

2016-11-01

Precise measurement of cadaver decomposition rate is the basis to accurate post-mortem interval (PMI) estimation. There are many approaches explored in recent years, however, it is still unsolved completely. Total volatile basic nitrogen (TVB-N), which is an important index to predict meat freshness and shelf life in food science, could serve as an indicator for measuring PMI associated decomposition rate of cadavers. The aim of this work was to establish a practical method to determine TVB-N in cadaver soft tissues (mainly skeletal muscle) for measuring decomposition rate. Determination of TVB-N in the simulation and animal experiments was conducted by steam distillation and conductometric titration using Kjeldahl distillation unit and conductivity meter. In simulation, standard concentrations of ammonium were used as TVB analogies, TVB-N contents were determined and the recovery rates of nitrogen were calculated. In animal experiment, TVB-N in skeletal muscle of forty-two rats was determined at different PMIs for 312 h at 24 °C ± 1 °C. The relationship between PMI and TVB-N was investigated also. The method showed high precision with 99%-100% recovery rates. TVB-N in skeletal muscle changed significantly with PMI especially after 24 h, and the data fit well to y = 3.35 E -5 x 3 -2.17 E -2 x 2 +6.13x-85.82 (adj. R 2  = 0.985). EC i (initial electrical conductivity in the samples just before titration) had positive linear relationship to final measured TVB-N values, y = 1.98x+16.16 (adj. R 2  = 0.985). The overall results demonstrated that the method is accurate, rapid and flexible, which could be expected as a basic technique for measuring decomposition rate in later PMI-estimation researches. Further studies are needed to validate our findings. Copyright © 2016 Elsevier Ltd and Faculty of Forensic and Legal Medicine. All rights reserved.

Feasibility study of using PET to determine nitrogen concentration after high energy photon irradiation

International Nuclear Information System (INIS)

Alghamdi, A.A.; Spyrou, N.M.; Al-Mokhlef, J.; Alhaj, A.

2007-01-01

The technique of photon activation analysis (PAA) is widely employed in many fields as an effective non-invasive tool for measuring elemental compositions and concentrations. In recent years there has been a revival and growing interest of PAA in general and for medical applications in particular. The feasibility of using a PET scanner (Ecat Exact 931) to determine nitrogen concentration in a dead rabbit is described. This method is based on the photon activation of 14 N(γ,n) 13 N (T 1/2 = 9.9 min) using an 18 MV photon beam Medical Linear Accelerator (Varian 2300EX). (author)

Nitrogen solubility in nickel base multicomponent melts

International Nuclear Information System (INIS)

Bol'shov, L.A.; Stomakhin, A.Ya.; Sokolov, V.M.; Teterin, V.G.

1984-01-01

Applicability of various methods for calculation of nitrogen solubility in high-alloyed nickel base alloys, containing Cr, Fe, W, Mo, Ti, Nb, has been estimated. A possibility is shown to use the formUla, derived for the calculation of nitrogen solubility in iron on the basis of statistical theory for a grid model of solution which does not require limitations for the content of a solvent component. The calculation method has been used for nickel alloys, with the concentration of solvent, iron, being accepted equal to zero, and employing parameters of nitrogen interaction as determined for iron-base alloys

Determination of nitrogen reduction levels necessary to reach groundwater quality targets in Slovenia.

Science.gov (United States)

Andelov, Miso; Kunkel, Ralf; Uhan, Jože; Wendland, Frank

2014-09-01

Within a collaborative project between Slovenian Environment Agency (ARSO) and Research Center Jülich (FZJ), nitrogen reduction levels necessary to reach groundwater quality targets in Slovenia were assessed. For this purpose the hydrological model GROWA-DENUZ was coupled with agricultural N balances and applied consistently to the whole territory of Slovenia in a spatial resolution of 100×100m. GROWA was used to determine the water balance in Slovenia for the hydrologic period 1971-2000. Simultaneously, the displaceable N load in soil was assessed from agricultural Slovenian N surpluses for 2011 and the atmospheric N deposition. Subsequently, the DENUZ model was used to assess the nitrate degradation in soil and, in combination with the percolation water rates from the GROWA model, to determine nitrate concentration in the leachate. The areas showing predicted nitrate concentrations in the leachate above the EU groundwater quality standard of 50mg NO3(-)/L have been identified as priority areas for implementing nitrogen reduction measures. For these "hot spot" areas DENUZ was used in a backward mode to quantify the maximal permissible nitrogen surplus levels in agriculture to guarantee a nitrate concentration in percolation water below 50mg NO3(-)/L. Model results indicate that additional N reduction measures should be implemented in priority areas rather than area-covering. Research work will directly support the implementation of the European Union Water Framework Directive in Slovenia, e.g., by using the maximal permissible nitrogen surplus levels as a framework for the derivation of regionally adapted and hence effective nitrogen reduction measures. Copyright © 2014. Published by Elsevier B.V.

Changes in the content of total nitrogen and mineral nitrogen in the basil herb depending on the cultivar and nitrogen nutrition

Directory of Open Access Journals (Sweden)

Katarzyna Dzida

2013-04-01

Full Text Available Among fundamental nutrients, nitrogen fertilization is considered one of the most effective factors affecting both the yield and the quality of plant material. Nitrogen form used for fertilizing is also of great importance. The aim of this study was to investigate the impact of nitrogen nutrition (calcium nitrate, ammonium nitrate, and urea as well as (green, purple, and‘Fino Verde’ on the chemical composition and yielding of basil (Ocimum basilicumL.. After drying the plant material at a temperature of 60°C and milling, total nitrogen was determined by means of Kjeldahl method, while mineral nitrogen content (N-NH 4, N-NO 3 was analyzed in 2% acetic acid extract. Yield of fresh basil matter depended significantly on the variety grown. The highest yields were obtained from a cultivar of ‘Fino Verde’ fertilized with ammonium nitrate. The purple variety plants fertilized with urea were characterized by a largest amount of total nitrogen. The‘Fino Verde’cultivar fertilized with urea accumulated the least quantities of nitrates in the basil herb.

Non liquid nitrogen-based-method for isolation of DNA from ...

African Journals Online (AJOL)

A simple, efficient, reliable and cost-effective method for isolation of total genomic DNA from fungi, suitable for polymerase chain reaction (PCR) amplification and other molecular applications was described. The main advantages of the method are: (1) does not require the use of liquid nitrogen for preparation of fungi DNA; ...

Temperature dependence of nitrogen solubility in iron base multicomponent melts

International Nuclear Information System (INIS)

Sokolov, V.M.; Koval'chuk, L.A.

1986-01-01

Method for calculating temperature dependence of nitrogen solubility in iron base multicomponent melts is suggested. Application areas of existing methods were determined and advantages of the new method for calculating nitrogen solubility in multicomponent-doped iron melts (Fe-Ni-Cr-Mo, Fe-Ni-Cr-Mn, Fe-Mo-V) at 1773-2073 K are shown

Estimation of nitrogen fixation in Saccharum spp. by 15N dilution method

International Nuclear Information System (INIS)

Singh, Mohan

1994-01-01

The amount of nitrogen fixed by bacteria associated with the roots of Saccharum spontaneum, S. sinense, and S. barberi has been estimated by 15 N-isotope dilution method using Sclerotachya fusca as a non-fixing control. S. spontaneum produced highest shoot dry weight among the species tested but maximum nitrogen was accumulated by S. barberi. Highest dilution in the 15 N-enrichment was observed in S. spontaneum followed by S. sinense and S. barberi in comparison to the control plant of Sclerotchya fusca. S. spontaneum derived 60 per cent followed by S. sinense 54 per cent and S. barberi 35 per cent of their total nitrogen requirement through fixation of nitrogen by diazotrophic bacteria associated with their roots. (author). 11 refs., 2 tabs

Combination of inoculation methods of Azospirilum brasilense with broadcasting of nitrogen fertilizer increases corn yield

Directory of Open Access Journals (Sweden)

Tânia Maria Müller

2015-01-01

Full Text Available Nitrogen (N is the most limiting nutrient for corn production. Thereby, the goal of the paper was to evaluate inoculation methods of Azospirillum brasilense in order to partially supply N required by the crop. The experiment was carried out in Guarapuava, PR, Brasil, in 2011/2012 growing season. Randomized blocks with factorial 3 inoculation methods (seed treatment, planting furrow and non-inoculated control x 5 doses of nitrogen (0, 75, 150, 225 and 300kg ha-1 x 8 replications was used as the experimental design. Leaf are index, foliar nitrogen content, total chlorophyll, grains per ear and yield were evaluated. There was significant interaction between inoculation methods and nitrogen fertilization to leaf area index, but not for yield. Inoculation with the diazotrophic bacteria provided yield increase of 702kg ha-1 for inoculation in seeding furrow and 432kg ha-1 for inoculation in seed treatment compared to the control, but both treatments did not differ between each other. Furthermore, total chlorophyll, grains per ear and yield were positively affected, with quadratic response, by the nitrogen fertilization in broadcasting

Effect of weed management methods and nitrogen fertilizer rates on ...

African Journals Online (AJOL)

Inefficient weed management practices and the use of inappropriate nitrogen fertilizer rates are the major causes of low yield of wheat in Ethiopia. Therefore, field experiments were conducted at Bobicho and Faate in southern Ethiopia to determine the effect of weed management practices and N fertilizer rates on grain yield ...

Development of a technique using MCNPX code for determination of nitrogen content of explosive materials using prompt gamma neutron activation analysis method

Energy Technology Data Exchange (ETDEWEB)

Nasrabadi, M.N., E-mail: mnnasrabadi@ast.ui.ac.ir [Department of Nuclear Engineering, Faculty of Advanced Sciences and Technologies, University of Isfahan, Isfahan 81746-73441 (Iran, Islamic Republic of); Bakhshi, F.; Jalali, M.; Mohammadi, A. [Department of Nuclear Engineering, Faculty of Advanced Sciences and Technologies, University of Isfahan, Isfahan 81746-73441 (Iran, Islamic Republic of)

2011-12-11

Nuclear-based explosive detection methods can detect explosives by identifying their elemental components, especially nitrogen. Thermal neutron capture reactions have been used for detecting prompt gamma 10.8 MeV following radioactive neutron capture by {sup 14}N nuclei. We aimed to study the feasibility of using field-portable prompt gamma neutron activation analysis (PGNAA) along with improved nuclear equipment to detect and identify explosives, illicit substances or landmines. A {sup 252}Cf radio-isotopic source was embedded in a cylinder made of high-density polyethylene (HDPE) and the cylinder was then placed in another cylindrical container filled with water. Measurements were performed on high nitrogen content compounds such as melamine (C{sub 3}H{sub 6}N{sub 6}). Melamine powder in a HDPE bottle was placed underneath the vessel containing water and the neutron source. Gamma rays were detected using two NaI(Tl) crystals. The results were simulated with MCNP4c code calculations. The theoretical calculations and experimental measurements were in good agreement indicating that this method can be used for detection of explosives and illicit drugs.

Integrated method for the measurement of trace nitrogenous atmospheric bases

Directory of Open Access Journals (Sweden)

D. Key

2011-12-01

Full Text Available Nitrogenous atmospheric bases are thought to play a key role in the global nitrogen cycle, but their sources, transport, and sinks remain poorly understood. Of the many methods available to measure such compounds in ambient air, few meet the current need of being applicable to the complete range of potential analytes and fewer still are convenient to implement using instrumentation that is standard to most laboratories. In this work, an integrated approach to measuring trace, atmospheric, gaseous nitrogenous bases has been developed and validated. The method uses a simple acid scrubbing step to capture and concentrate the bases as their phosphite salts, which then are derivatized and analyzed using GC/MS and/or LC/MS. The advantages of both techniques in the context of the present measurements are discussed. The approach is sensitive, selective, reproducible, as well as convenient to implement and has been validated for different sampling strategies. The limits of detection for the families of tested compounds are suitable for ambient measurement applications (e.g., methylamine, 1 pptv; ethylamine, 2 pptv; morpholine, 1 pptv; aniline, 1 pptv; hydrazine, 0.1 pptv; methylhydrazine, 2 pptv, as supported by field measurements in an urban park and in the exhaust of on-road vehicles.

Separation of ammonium and hydroxylamine nitrogen for the 15N determination

International Nuclear Information System (INIS)

Russow, R.

1990-01-01

After preseparation of the nitrogen compounds derived from microbial nitrification on a strong basic anion exchanger it is found hydroxylamine together with ammonium in one fraction. The nitrogen of this two compounds can be separated for the emission spectrometric 15 N analysis by the selective oxidation of the hydroxylamine to nitrite/nitrate using an iodine solution. Thus the hydroxylamine is protected against disproportionation during the following ammonium isolation by means of steam disillation in an alkaline medium. After that the nitrite/nitrate is reduced to ammonium using ferrous hydroxide and can than be librated by steam distillation. The performance of the method under discussion will be demonstrated by analysing solutions with known ammonium and hydroxylamine contents. (author)

Determinação das formas de nitrogênio e nitrogênio total em rochas-reservatório de petróleo por destilação com arraste de vapor e método do indofenol Determination of nitrogen forms and total nitrogen in petroleum reservoir rocks by steam distillation and the indophenol method

Directory of Open Access Journals (Sweden)

Lílian Irene Dias da Silva

2006-02-01

Full Text Available Several extraction procedures are described for the determination of exchangeable and fixed ammonium, nitrate + nitrite, total exchangeable nitrogen and total nitrogen in certified reference soils and petroleum reservoir rock samples by steam distillation and indophenol method. After improvement of the original distillation system, an increase in worker safety, a reduction in time consumption, a decrease of 73% in blank value and an analysis without ammonia loss, which could possibly occur, were achieved. The precision (RSD < 8%, n = 3 and the detection limit (9 mg kg-1 NH4+-N are better than those of published procedures.

Attempt at estimating the rate of symbiotic fixation of nitrogen in the Lupine by natural isotopic tracing (/sup 15/N)

Energy Technology Data Exchange (ETDEWEB)

Amarger, Noelle [INRA Centre de Recherches de Dijon, 21 (France). Lab. de Microbiologie des Sols; Mariotti, Andre; Mariotti, Francoise [Paris-6 Univ., 75 (France)

1977-06-06

The rate of nitrogen fixation by a Rhizobium-Leguminous plant pair has been determined by natural isotopic tracing (/sup 15/N). After determining the isotopic fractionation coefficients between atmospheric nitrogen and plant nitrogen on the one hand (epsilon=-0.9) and nitrogen of the substrate and plant nitrogen on the other hand (epsilon=-1.1), the rate of nitrogen fixation by way of mixed nutrition cultures was calculated. The method is more accurate than standard methods.

Assessment of nitrogen oxide emission for designing boilers fired with coal dust

Energy Technology Data Exchange (ETDEWEB)

Kotler, V.R.; Gusev, L.N.; Babii, V.I.

1983-09-01

A method for forecasting emission of nitrogen oxides from steam boilers fired with coal is described. The method produces accurate results when nitrogen oxide emission from furnaces with straight-flow burners and turbulent-type burners fired with coal dusts is forecast. Oxides formed by decomposition of chemical compounds in coal (so-called 'fuel' nitrogen oxides) and nitrogen oxides formed by oxidation of molecular nitrogen by atomic oxygen (so-called 'thermal' nitrogen oxides) are evaluated. Zones in which the two types of nitrogen oxide are formed in flames are characterized. Factors which influence formation of nitrogen oxides in a furnace are evaluated: excess air, flue gas recirculation, design of a furnace and burners, movement of air and coal dust mixture in a furnace, temperature, methods for coal dust preparation, coal dust properties. Equations for forecasting emission of nitrogen oxides from furnaces are derived. Nomograms for easy calculation of emission are also given. Examples of using the method for forecasting emission of nitrogen oxides from furnaces fired with coal from the Kuzbass, the Donbass and Ehkibastuz are discussed. Comparisons of emission of nitrogen oxides calculated on the basis of the method and emission determined experimentally show that forecasting accuracy is high and errors do not exceed 10%. 5 references.

Balance sheet method assessment for nitrogen fertilization in bread wheat: I. yield and quality

Directory of Open Access Journals (Sweden)

Maria Corbellini

2006-09-01

Full Text Available In the European Union the production of high quality wheat is mainly located in the Mediterranean regions where the climatic conditions positively affect protein concentration in the grain. High quality wheat calls for proper management of nitrogen fertilization, thus there is a need to verify whether the limitations imposed by local governments on maximum rate of nitrogen fertilization admitted may affect bread making quality. Trials were conducted in fourteen environments (E to study the effects of different nitrogen fertilizations on eight cultivars (C, belonging to four quality grades (Q. Nitrogen (N was applied to crops according to three rates/modalities: N1 corresponding to the maximum rate admitted calculated according to a balance sheet method and distributed at the stage of spike initiation; N2 with 50 kg ha-1 of nitrogen more than N1, also distributed at the stage of spike initiation; N3 with 50 kg ha-1 of nitrogen more than N1 but distributed at the stage of flag leaf appearance. The effects of environment, nitrogen and cultivar were significant for grain yield, test weight, 1000 kernel weight, heading time, plant height and for quality traits (protein content and alveograph indices. The existence of variability among cultivars and quality grades in the response to rate and timing of nitrogen fertilization was demonstrated by the significance of NxC and NxQ interactions. Dry matter and nitrogen contents of plant at anthesis and at harvest were significantly affected by the main sources of variation. High quality cultivars yielded more grain of better quality with higher N rates (N2 and N3 as compared to the maximum rate of nitrogen admitted by the local government (N1. These results demonstrated that the adopted balance sheet method for the calculation of N requirements of wheat crop adversely affects the full potential expression of the cultivars belonging to superior bread making quality grades.

Balance sheet method assessment for nitrogen fertilization in bread wheat: I. yield and quality

Directory of Open Access Journals (Sweden)

Mario Monotti

2011-02-01

Full Text Available In the European Union the production of high quality wheat is mainly located in the Mediterranean regions where the climatic conditions positively affect protein concentration in the grain. High quality wheat calls for proper management of nitrogen fertilization, thus there is a need to verify whether the limitations imposed by local governments on maximum rate of nitrogen fertilization admitted may affect bread making quality. Trials were conducted in fourteen environments (E to study the effects of different nitrogen fertilizations on eight cultivars (C, belonging to four quality grades (Q. Nitrogen (N was applied to crops according to three rates/modalities: N1 corresponding to the maximum rate admitted calculated according to a balance sheet method and distributed at the stage of spike initiation; N2 with 50 kg ha-1 of nitrogen more than N1, also distributed at the stage of spike initiation; N3 with 50 kg ha-1 of nitrogen more than N1 but distributed at the stage of flag leaf appearance. The effects of environment, nitrogen and cultivar were significant for grain yield, test weight, 1000 kernel weight, heading time, plant height and for quality traits (protein content and alveograph indices. The existence of variability among cultivars and quality grades in the response to rate and timing of nitrogen fertilization was demonstrated by the significance of NxC and NxQ interactions. Dry matter and nitrogen contents of plant at anthesis and at harvest were significantly affected by the main sources of variation. High quality cultivars yielded more grain of better quality with higher N rates (N2 and N3 as compared to the maximum rate of nitrogen admitted by the local government (N1. These results demonstrated that the adopted balance sheet method for the calculation of N requirements of wheat crop adversely affects the full potential expression of the cultivars belonging to superior bread making quality grades.

Nitrogen use efficiency evaluation of aerobic rice under field capacity water potential using 15N isotopic tracer technique

International Nuclear Information System (INIS)

Wahid, Ahmad Nazrul Abd; Rahim, Sahibin Abd; Rahim, Khairuddin Abdul; Harun, Abdul Rahim

2015-01-01

This study was carried out to evaluate the efficiency use of the nitrogen fertilizer on aerobic rice varieties MR219-4 and MR219-9 which were grown aerobically under field capacity water potential at the controlled environment area or shield house. Direct 15 N isotope tracer method was used in this study, whereby the 15 N isotope was utilized as a tracer for nitrogen nutrient uptake. 15 N isotope presence in the samples is determined by using emission spectrometer analysis and percentage of total nitrogen is determined by using Kjeldahl method. 15 N atom access value contained in the sample will be used in determining the effectiveness of the use of nitrogen in fertilizers through the specific calculation formulas. In this work, the data several data of nitrogen derived from fertilizer (Ndff), total nitrogen, nitrogen uptake and nitrogen use efficiency was obtained

Cattle slurry on grassland - application methods and nitrogen use efficiency

NARCIS (Netherlands)

Lalor, S.T.J.

2014-01-01

Cattle slurry represents a significant resource on grassland-based farming systems. The objective of this thesis was to investigate and devise cattle slurry application methods and strategies that can be implemented on grassland farms to improve the efficiency with which nitrogen (N) in

Characterisation and quantification of organic phosphorus and organic nitrogen components in aquatic systems: A Review

Energy Technology Data Exchange (ETDEWEB)

Worsfold, Paul J. [School of Earth, Ocean and Environmental Sciences, University of Plymouth, Drake Circus, Plymouth PL48AA (United Kingdom)], E-mail: pworsfold@plymouth.ac.uk; Monbet, Philippe [School of Earth, Ocean and Environmental Sciences, University of Plymouth, Drake Circus, Plymouth PL48AA (United Kingdom); Water Studies Centre, School of Chemistry, Monash University, Clayton 3800, Victoria (Australia); Tappin, Alan D.; Fitzsimons, Mark F.; Stiles, David A. [School of Earth, Ocean and Environmental Sciences, University of Plymouth, Drake Circus, Plymouth PL48AA (United Kingdom); McKelvie, Ian D. [Water Studies Centre, School of Chemistry, Monash University, Clayton 3800, Victoria (Australia)

2008-08-22

This review provides a critical assessment of knowledge regarding the determination of organic phosphorus (OP) and organic nitrogen (ON) in aquatic systems, with an emphasis on biogeochemical considerations and analytical challenges. A general background on organic phosphorus and organic nitrogen precedes a discussion of sample collection, extraction, treatment/conditioning and preconcentration of organic phosphorus/nitrogen from sediments, including suspended particulate matter, and waters, including sediment porewaters. This is followed by sections on the determination of organic phosphorus/nitrogen components. Key techniques covered for organic phosphorus components are molecular spectrometry, atomic spectrometry and enzymatic methods. For nitrogen the focus is on the measurement of total organic nitrogen concentrations by carbon hydrogen nitrogen analysis and high temperature combustion, and organic nitrogen components by gas chromatography, high-performance liquid chromatography, gel electrophoresis, mass spectrometry, nuclear magnetic resonance spectrometry, X-ray techniques and enzymatic methods. Finally future trends and needs are discussed and recommendations made.

Rapid synthesis of nitrogen doped titania with mixed crystal lattice via microwave-assisted hydrothermal method

International Nuclear Information System (INIS)

Zhang Peilin; Liu Bin; Yin Shu; Wang Yuhua; Petrykin, Valery; Kakihana, Masato; Sato, Tsugio

2009-01-01

A microwave-assisted hydrothermal method was employed to synthesize nitrogen doped titania nanoparticles. Due to the high heating efficiency of microwave, rapid synthesis could be achieved in comparison with the conventional oven. Mixed crystal lattice was found existing in the obtained product, and the phase transformation behaviour under calcination was studied by XRD measurement together with Raman spectroscopy in details. The obtained nitrogen doped titania showed high specific surface area, about 300 m 2 g -1 . Photocatalytic activity in destructing NO x gas by the prepared sample exceeded that of commercial titania (P 25) or nitrogen doped titania synthesized by conventional hydrothermal method, under both visible-light and ultraviolet-light irradiation.

Genetics parameters and association of NUE methods in maize under different nitrogen levels

Directory of Open Access Journals (Sweden)

Edmar Vinícius de Carvalho

2016-03-01

Full Text Available This work aimed to study the association of four nitrogen use efficiency (NUE methods and the genetic parameters of grain weight in two groups of maize genotypes, under different levels of nitrogen supply, in the season 2012/13. 16 field experiments were carried out in the city of Gurupi, Tocantins, Brazil. Each genotype group was evaluated in different seeding date, and each one was tested with different levels of nitrogen supply. In all experiments the experimental design was completely randomized blocks with three repetitions. The following trait was evaluated after stage R6: grain yield (GY, and after, four indices of efficiency/stress to nitrogen were estimated. The Pearson correlation coefficients, estimated among the indices, were all significant (P < 0.01. Among the seeding dates, the average heritability of GY was 54.4% and among the levels of nitrogen supply, the following values were observed: 60.4% (low N; 50.9% (medium N; 51.2% (high N. There is the possibility of the use of environments with lower nitrogen supply in the search for superior and more efficient genotypes for the GY, and based on our results, the Low N index is more adequate.

Organic carbon and nitrogen availability determine bacterial community composition in paddy fields of the Indo-Gangetic plain.

Science.gov (United States)

Kumar, Arvind; Rai, Lal Chand

2017-07-01

Soil quality is an important factor and maintained by inhabited microorganisms. Soil physicochemical characteristics determine indigenous microbial population and rice provides food security to major population of the world. Therefore, this study aimed to assess the impact of physicochemical variables on bacterial community composition and diversity in conventional paddy fields which could reflect a real picture of the bacterial communities operating in the paddy agro-ecosystem. To fulfill the objective; soil physicochemical characterization, bacterial community composition and diversity analysis was carried out using culture-independent PCR-DGGE method from twenty soils distributed across eight districts. Bacterial communities were grouped into three clusters based on UPGMA cluster analysis of DGGE banding pattern. The linkage of measured physicochemical variables with bacterial community composition was analyzed by canonical correspondence analysis (CCA). CCA ordination biplot results were similar to UPGMA cluster analysis. High levels of species-environment correlations (0.989 and 0.959) were observed and the largest proportion of species data variability was explained by total organic carbon (TOC), available nitrogen, total nitrogen and pH. Thus, results suggest that TOC and nitrogen are key regulators of bacterial community composition in the conventional paddy fields. Further, high diversity indices and evenness values demonstrated heterogeneity and co-abundance of the bacterial communities.

Use of nitrogen cryogun for separating duct tape and recovery of latent fingerprints with a powder suspension method.

Science.gov (United States)

Bailey, James A; Crane, Jonathan Stuart

2011-07-15

Duct tape is sometimes recovered as physical evidence in crimes. The purpose of this study was to determine the quality of latent prints on the adhesive and non-adhesive surfaces of duct tape samples that were separated using three methods. Three hundred donor fingerprint impressions were deposited on duct tape. Sections of duct tape were affixed to sections of cardboard and a fingerprint placed on the non-adhesive surface of the tape. A second layer of duct tape was prepared and a fingerprint placed on the adhesive side of the tape and then the tape was affixed to the piece of tape on the cardboard. After a 24-h period, the samples were separated using gradual force, liquid nitrogen applied with a cryogun and an adhesive neutralizer to separate the layers of tape. The recovered fingerprints were processed with a fingerprint powder suspension method. The recovered fingerprint images were evaluated and rated as +1, +2, or +3. The liquid nitrogen spray separation method yielded the highest number of +3 prints. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Dissolved organic nitrogen recalcitrance and bioavailable nitrogen quantification for effluents from advanced nitrogen removal wastewater treatment facilities

International Nuclear Information System (INIS)

Fan, Lu; Brett, Michael T.; Jiang, Wenju; Li, Bo

2017-01-01

The objective of this study was to determine the composition of nitrogen (N) in the effluents of advanced N removal (ANR) wastewater treatment plants (WWTPs). This study also tested two different experimental protocols for determining dissolved N recalcitrance. An analysis of 15 effluent samples from five WWTPs, showed effluent concentrations and especially effluent composition varied greatly from one system to the other, with total nitrogen (TN) ranging between 1.05 and 8.10 mg L −1 . Nitrate (NO 3 − ) accounted for between 38 ± 32% of TN, and ammonium accounted for a further 29 ± 28%. All of these samples were dominated by dissolved inorganic nitrogen (DIN; NO 3 −  + NH 4 + ), and uptake experiments indicated the DIN fraction was as expected highly bioavailable. Dissolved organic N (DON) accounted for 20 ± 11% for the total dissolved N in these effluents, and uptake experiments indicated the bioavailability of this fraction varied between 27 ± 26% depending on the WWTP assessed. These results indicate near complete DIN removal should be the primary goal of ANR treatment systems. The comparison of bioavailable nitrogen (BAN) quantification protocols showed that the dissolved nitrogen uptake bioassay approach was clearly a more reliable way to determine BAN concentrations compared to the conventional cell yield protocol. Moreover, because the nitrogen uptake experiment was much more sensitive, this protocol made it easier to detect extrinsic factors (such as biological contamination or toxicity) that could affect the accuracy of these bioassays. Based on these results, we recommend the nitrogen uptake bioassay using filtered and autoclaved samples to quantify BAN concentrations. However, for effluent samples indicating toxicity, algal bioassays will not accurately quantify BAN. - Highlights: • DIN was the dominated N pool for most of the tested effluent samples. • DON bioavailability considerably varied depending on the WWTP assessed. �

Isotopic-spectral determination of hydrogen, nitrogen, oxygen and carbon in semiconductor materials

International Nuclear Information System (INIS)

Dudich, G.K.; Eremeev, V.A.; Li, V.N.; Nemets, V.M.

1981-01-01

Techniques of low-temperature isotopic-spectral determination of impurities of hydrogen, nitrogen, oxygen and carbon in semiconductor materials Bi, Ge, Pb tellurides are developed. The techniques include selection into special vessel with the known volume (exchanger) of sample analyzed, dosed introduction into exchanger of rare isotope of the element determined ( 2 H, 15 N, 18 O, 13 C) in the form of isotope-containing gas, balancing of the determined element isotopes in the system sample-isotope, containing gas, spectroscopic, determination of its isotope composition in gaseous phase of the system and calculation of the amount of the element determined in the sample. The lower boundaries of the amounts determined constitute 10 -7 , 10 -7 , 10 -6 and 10 -5 mass % respectively when sample of 20 g are used [ru

Nitrogen content determinations in different stages of thermal treatment involved in conversion of ammonium diuranate to uranium metal

International Nuclear Information System (INIS)

Shrivastava, K.C.; Shelke, G.P.

2017-01-01

Determination of nitrogen content in the uranium metal and uranium oxide based reactor fuels is important to meet the requirement of specifications given by fuel designer. Therefore, a systematic study was carried out to determine the variations in nitrogen content during the conversion of ammonium diuranate (ADU) to uranium oxides (UO 3 and UO 2 ), and finally to uranium metal by inert gas fusion-thermal conductivity detection (IGF-TCD) technique. To understand the measured nitrogen content variations, the thermal decomposition study of ADU was carried out using thermogravimetry (TG)/differential thermogravimetry (DTG) and differential thermal analysis (DTA) in the temperature range of 25-1073 K. Powder X-ray diffraction (XRD) technique was used to confirm the formation of uranium oxide precursors at different temperature. (author)

Nitrogen removal from wastewater by a catalytic oxidation method.

Science.gov (United States)

Huang, T L; Macinnes, J M; Cliffe, K R

2001-06-01

The ammonia-containing waste produced in industries is usually characterized by high concentration and high temperature, and is not treatable by biological methods directly. In this study, a hydrophobic Pt/SDB catalyst was first used in a trickle-bed reactor to remove ammonia from wastewater. In the reactor, both stripping and catalytic oxidation occur simultaneously. It was found that higher temperature and higher oxygen partial pressure enhanced the ammonia removal. A reaction pathway, which involves oxidizing ammonia to nitric oxide, which then further reacts with ammonia to produce nitrogen and water, was confirmed. Small amounts of by-products, nitrites and nitrates were also detected in the resultant reaction solution. These compounds came from the absorption of nitrogen oxides. Both the minimum NO2- selectivity and maximum ammonia removal were achieved when the resultant pH of treated water was near 7.5 for a feed of unbuffered ammonia solution.

Use of 15N dilution method for screening soybean lines with high yield and high nitrogen fixation ability

International Nuclear Information System (INIS)

Li Haixian; Li Xinmin; Danso, S.K.A.

1998-01-01

15 N dilution method was used for screening soybean lines with high nitrogen fixation ability. Screened lines 1005, 8502, 2096, 943, 1454 and Dongnong-42 have high nitrogen fixation ability with their % Ndfa of about 70%. 1454 and 1555 are both high yield and high nitrogen fixation lines. The ability of nitrogen fixation was not related to the yield, but related to maturing time. The cultivars with different maturing time have different levels of nitrogen fixation ability. The longer the maturing period is, the greater the ability of nitrogen fixation it has. There were ten cultivars or lines used in the test of 1992 and 1994. Although the weather condition were greatly different between the two years the results of seven cultivars or lines were the same, indicating that nitrogen fixation ability of the soybean is stable with years. Using 15 N dilution method to estimate nitrogen fixation ability of soybean is reliable, however, the % Ndfa of lines 8502 and 2096 increased by 19% in 1994, a rainy year, indicating that a change in % Ndfa with a few varieties maybe caused by weather

The role of char and tar in determining the gas-phase partitioning of nitrogen during biomass gasification

International Nuclear Information System (INIS)

Broer, Karl M.; Brown, Robert C.

2015-01-01

Highlights: • Switchgrass was gasified at an equivalence ratio of zero and 650–850 °C. • Short residence times were employed to minimize secondary reactions. • Char- and tar-bound nitrogen, NH_3, HCN, and N_2 were all significant products. • Increasing temperature leads to increased release of gaseous nitrogen compounds. • Kinetic models of gasification should include nitrogen release from char and tar. - Abstract: Gasification is an attractive option for converting biomass into fuels and chemicals. Most biomass contains significant amounts of fuel-bound nitrogen (FBN), which partially converts into ammonia (NH_3) and hydrogen cyanide (HCN) during gasification. These nitrogen compounds are problematic as they can lead to NO_X emissions or catalyst poisoning in downstream applications of syngas. FBN can convert to other products as well, including diatomic nitrogen (N_2), char-bound nitrogen (char-N), and tar-bound nitrogen (tar-N). Efforts to predict concentrations of NH_3 and HCN have been hindered by a lack of accurate, comprehensive measurements of nitrogen partitioning among gasification products. The present study gasified switchgrass under allothermal, short residence time conditions and measured NH_3, HCN, char-N, and tar-N as a function of temperature in the range of 650–850 °C with diatomic nitrogen determined by difference. It was found that a major portion of FBN was retained in the char and tar products. As temperature was increased, char and tar were consumed, releasing nitrogen as gaseous NH_3 and HCN. This increase in undesirable nitrogen compounds is contrary to the predictions of most gasification models, which overlook the presence of significant nitrogen in char and tar even if they include tar cracking and char gasification reactions. The results of this study demonstrate that gas-phase reactions alone are not sufficient to predict the fate of nitrogen during gasification. In order for modeling efforts to obtain more accurate

Nitrogen use efficiency evaluation of aerobic rice under field capacity water potential using {sup 15}N isotopic tracer technique

Energy Technology Data Exchange (ETDEWEB)

Wahid, Ahmad Nazrul Abd, E-mail: a-nazrul@nuclearmalaysia.gov.my [Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, 43600, Selangor (Malaysia); Malaysian Nuclear Agency, Bangi, 43000 Kajang, Selangor (Malaysia); Rahim, Sahibin Abd, E-mail: haiyan@ukm.edu.my [Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, 43600, Selangor (Malaysia); Rahim, Khairuddin Abdul; Harun, Abdul Rahim [Malaysian Nuclear Agency, Bangi, 43000 Kajang, Selangor (Malaysia)

2015-09-25

This study was carried out to evaluate the efficiency use of the nitrogen fertilizer on aerobic rice varieties MR219-4 and MR219-9 which were grown aerobically under field capacity water potential at the controlled environment area or shield house. Direct {sup 15}N isotope tracer method was used in this study, whereby the {sup 15}N isotope was utilized as a tracer for nitrogen nutrient uptake. {sup 15}N isotope presence in the samples is determined by using emission spectrometer analysis and percentage of total nitrogen is determined by using Kjeldahl method. {sup 15}N atom access value contained in the sample will be used in determining the effectiveness of the use of nitrogen in fertilizers through the specific calculation formulas. In this work, the data several data of nitrogen derived from fertilizer (Ndff), total nitrogen, nitrogen uptake and nitrogen use efficiency was obtained.

Design of a nitrogen purification system with cryogenic method for neutrino detection.

Science.gov (United States)

Peng, Zhang; Zhongjun, Hu; Bingming, Wang; Qing, Li

2018-04-04

In order to detect the neutrino with liquid scintillation detector, high-purity nitrogen is essential for gas stripping in this detector. Therefore, it is necessary to design a purification system for the detector to purify nitrogen. Using the method of low temperature adsorption for the purification system, the key designs including the flow path, the adsorber and the selection of activated carbon, are introduced in this study. In these designs, the selection of activated carbon is the most important because the adsorption characteristic of the carbon is related to the performance of the purification system. The method of grand canonical ensemble Monte Carlo is adopted to simulate the adsorption of radon by the activated carbon with its slit pore model. Using this method, the working temperature and the key characteristic of the activated carbon are obtained. Copyright © 2018 Elsevier Ltd. All rights reserved.

On nitrogen condensation in hypersonic nozzle flows: Numerical method and parametric study

KAUST Repository

Lin, Longyuan; Cheng, Wan; Luo, Xisheng; Qin, Fenghua

2013-01-01

A numerical method for calculating two-dimensional planar and axisymmetric hypersonic nozzle flows with nitrogen condensation is developed. The classical nucleation theory with an empirical correction function and the modified Gyarmathy model

Electrodeposited nitrogen-doped graphene/carbon nanotubes nanocomposite as enhancer for simultaneous and sensitive voltammetric determination of caffeine and vanillin

Energy Technology Data Exchange (ETDEWEB)

Jiang, Lin; Ding, Yaping, E-mail: wdingyp@sina.com; Jiang, Feng; Li, Li; Mo, Fan

2014-06-23

Graphical abstract: A nanocomposite of nitrogen-doped graphene (NGR) and nitrogen-doped carbon nanotubes (NCNTs) was first modified onto an electrode through electrodeposition method and employed to sensitively detect caffeine and vanillin simultaneously for the first time. - Highlights: • The first electrochemical sensor for caffeine (CAF) and vanillin (VAN). • NGR–NCNTs was modified through electrodeposition for the first time. • The sensor was qualified for real sample determination with satisfactory results. - Abstract: A nitrogen-doped graphene/carbon nanotubes (NGR–NCNTs) nanocomposite was employed into the study of the electrochemical sensor via electrodeposition for the first time. The morphology and structure of NGR–NCNTs nanocomposite were investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), respectively. Meanwhile, the electrochemical performance of the glassy carbon electrode (GCE) modified with electrodeposited NGR–NCNTs (ENGR–NCNTs/GCE) towards caffeine (CAF) and vanillin (VAN) determination was demonstrated by cyclic voltammetry (CV) and square wave voltammetry (SWV). Under optimal condition, ENGR–NCNTs/GCE exhibited a wide linearity of 0.06–50 μM for CAF and 0.01–10 μM for VAN with detection limits of 0.02 μM and 3.3 × 10{sup −3} μM, respectively. Furthermore, the application of the proposed sensor in food products was proven to be practical and reliable. The desirable results show that the ENGR–NCNTs nanocomposite has promising potential in electrocatalytic biosensor application.

Electrodeposited nitrogen-doped graphene/carbon nanotubes nanocomposite as enhancer for simultaneous and sensitive voltammetric determination of caffeine and vanillin

International Nuclear Information System (INIS)

Jiang, Lin; Ding, Yaping; Jiang, Feng; Li, Li; Mo, Fan

2014-01-01

Graphical abstract: A nanocomposite of nitrogen-doped graphene (NGR) and nitrogen-doped carbon nanotubes (NCNTs) was first modified onto an electrode through electrodeposition method and employed to sensitively detect caffeine and vanillin simultaneously for the first time. - Highlights: • The first electrochemical sensor for caffeine (CAF) and vanillin (VAN). • NGR–NCNTs was modified through electrodeposition for the first time. • The sensor was qualified for real sample determination with satisfactory results. - Abstract: A nitrogen-doped graphene/carbon nanotubes (NGR–NCNTs) nanocomposite was employed into the study of the electrochemical sensor via electrodeposition for the first time. The morphology and structure of NGR–NCNTs nanocomposite were investigated by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), respectively. Meanwhile, the electrochemical performance of the glassy carbon electrode (GCE) modified with electrodeposited NGR–NCNTs (ENGR–NCNTs/GCE) towards caffeine (CAF) and vanillin (VAN) determination was demonstrated by cyclic voltammetry (CV) and square wave voltammetry (SWV). Under optimal condition, ENGR–NCNTs/GCE exhibited a wide linearity of 0.06–50 μM for CAF and 0.01–10 μM for VAN with detection limits of 0.02 μM and 3.3 × 10 −3 μM, respectively. Furthermore, the application of the proposed sensor in food products was proven to be practical and reliable. The desirable results show that the ENGR–NCNTs nanocomposite has promising potential in electrocatalytic biosensor application

Potential for chlorate interference in ion chromatographic determination of total nitrogen in natural waters following alkaline persulfate digestion.

Science.gov (United States)

Halstead, J A; Edwards, J; Soracco, R J; Armstrong, R W

1999-10-01

Determination of total nitrogen in aqueous samples after thermal potassium peroxydisulfate (persulfate) digestion is a commonly used alternative to the tedious Kjeldahl procedure. When ion chromatography is used to quantify the nitrate formed during digestion, there is a potential for interference from a chlorate peak if the digested sample initially contained chloride in concentrations close to or greater than the concentration of nitrogen. It was determined that this interference can be avoided either by using chromatographic conditions which cleanly resolve the nitrate and chlorate peaks (e.g., the Dionex AG9-HG column) or by using digestion reagent concentrations chosen to maintain a high pH throughout the digestion. The second alternative is not a viable option for investigators using a single digestion for both total nitrogen (TN) and total phosphorus (TP) analysis.

Nitrogen cycling in a forest stream determined by a 15N tracer addition

Science.gov (United States)

Patrick J. Mullholland; Jennifer L. Tank; Diane M. Sanzone; Wilfred M. Wollheim; Bruce J. Peterson; Jackson R. Webster; Judy L. Meyer

2000-01-01

Nitrogen uptake and cycling was examined using a six-week tracer addition of 15N-labeled ammonium in early spring in Waer Branch, a first-order deciduous forest stream in eastern Tennessee. Prior to the 15N addition, standing stocks of N were determined for the major biomass compartments. During and after the addition,

Determination of heat transfer coefficients in plastic French straws plunged in liquid nitrogen.

Science.gov (United States)

Santos, M Victoria; Sansinena, M; Chirife, J; Zaritzky, N

2014-12-01

The knowledge of the thermodynamic process during the cooling of reproductive biological systems is important to assess and optimize the cryopreservation procedures. The time-temperature curve of a sample immersed in liquid nitrogen enables the calculation of cooling rates and helps to determine whether it is vitrified or undergoes phase change transition. When dealing with cryogenic liquids, the temperature difference between the solid and the sample is high enough to cause boiling of the liquid, and the sample can undergo different regimes such as film and/or nucleate pool boiling. In the present work, the surface heat transfer coefficients (h) for plastic French straws plunged in liquid nitrogen were determined using the measurement of time-temperature curves. When straws filled with ice were used the cooling curve showed an abrupt slope change which was attributed to the transition of film into nucleate pool boiling regime. The h value that fitted each stage of the cooling process was calculated using a numerical finite element program that solves the heat transfer partial differential equation under transient conditions. In the cooling process corresponding to film boiling regime, the h that best fitted experimental results was h=148.12±5.4 W/m(2) K and for nucleate-boiling h=1355±51 W/m(2) K. These values were further validated by predicting the time-temperature curve for French straws filled with a biological fluid system (bovine semen-extender) which undergoes freezing. Good agreement was obtained between the experimental and predicted temperature profiles, further confirming the accuracy of the h values previously determined for the ice-filled straw. These coefficients were corroborated using literature correlations. The determination of the boiling regimes that govern the cooling process when plunging straws in liquid nitrogen constitutes an important issue when trying to optimize cryopreservation procedures. Furthermore, this information can lead to

Round Robin test for the determination of nitrogen concentration in solid Lithium

International Nuclear Information System (INIS)

Favuzza, P.; Antonelli, A.; Furukawa, T.; Groeschel, F.; Hedinger, R.; Higashi, T.; Hirakawa, Y.; Iijima, M.; Ito, Y.; Kanemura, T.; Knaster, J.; Kondo, H.; Miccichè, G.; Nitti, F.S.; Ohira, S.; Severi, M.; Sugimoto, M.; Suzuki, A.; Traversi, R.; Wakai, E.

2016-01-01

Highlights: • Nitrogen contained in solid Lithium is converted into Ammonium ion. • Ammonium ion is suitably quantified by ionic chromatograph or by Ammonia sensor. • Good agreement of the partner’s results has been achieved. • Maximum operative reproducibility and blank subtraction are necessary. - Abstract: Three different partners, ENEA, JAEA ed University of Tokyo, have been involved during 2014–2015 in the Round Robin experimentation for the assessment of the soundness of the analitycal procedure for the determination of the Nitrogen impurities contained inside a solid Lithium sample. Two different kinds of Lithium samples, differing by about an order of magnitude in Nitrogen concentration (∼230 wppm; ∼20–30 wppm), have been selected for this cross analysis. The agreement of the achieved results appears very good for what concerns the most concentrated Lithium and indicates each partner’s procedure is appropriate and intrinsecally able to lead to meaningful values, characterized by a relative uncertainty of just few %. The smaller agreement in the case of the less concentrated Lithium anyway points out that particular attention must be paid to reduce as much as possible any source of external contamination and highlights the importance of the proper blank subtraction.

Round Robin test for the determination of nitrogen concentration in solid Lithium

Energy Technology Data Exchange (ETDEWEB)

Favuzza, P., E-mail: paolo.favuzza@enea.it [ENEA Center, Via Madonna del Piano 10, 50019 Sesto Fiorentino (Italy); Antonelli, A. [ENEA Research Center, Brasimone, 40035, Camugnano (Italy); Furukawa, T. [JAEA Research Center, Tokai-mura, Ibaraki (Japan); Groeschel, F. [KIT Research Center, Hermann-von-Helmholtz-Platz 1,76344 Eggenstein-Leopoldshafen (Germany); Hedinger, R. [F4E Research Center, Boltzmannstraße 2, 85748 Garching (Germany); Higashi, T. [University of Tokyo (Japan); Hirakawa, Y.; Iijima, M.; Ito, Y.; Kanemura, T. [JAEA Research Center, Tokai-mura, Ibaraki (Japan); Knaster, J. [IFMIF-EVEDA Project Team, Rokkasho (Japan); Kondo, H. [JAEA Research Center, Tokai-mura, Ibaraki (Japan); Miccichè, G.; Nitti, F.S. [ENEA Research Center, Brasimone, 40035, Camugnano (Italy); Ohira, S. [JAEA Research Center, Tokai-mura, Ibaraki (Japan); Severi, M. [University of Firenze, Via della Lastruccia 3, 50019 Sesto Fiorentino (Italy); Sugimoto, M. [JAEA Research Center, Rokkasho (Japan); Suzuki, A. [University of Tokyo (Japan); Traversi, R. [University of Firenze, Via della Lastruccia 3, 50019 Sesto Fiorentino (Italy); Wakai, E. [JAEA Research Center, Tokai-mura, Ibaraki (Japan)

2016-06-15

Highlights: • Nitrogen contained in solid Lithium is converted into Ammonium ion. • Ammonium ion is suitably quantified by ionic chromatograph or by Ammonia sensor. • Good agreement of the partner’s results has been achieved. • Maximum operative reproducibility and blank subtraction are necessary. - Abstract: Three different partners, ENEA, JAEA ed University of Tokyo, have been involved during 2014–2015 in the Round Robin experimentation for the assessment of the soundness of the analitycal procedure for the determination of the Nitrogen impurities contained inside a solid Lithium sample. Two different kinds of Lithium samples, differing by about an order of magnitude in Nitrogen concentration (∼230 wppm; ∼20–30 wppm), have been selected for this cross analysis. The agreement of the achieved results appears very good for what concerns the most concentrated Lithium and indicates each partner’s procedure is appropriate and intrinsecally able to lead to meaningful values, characterized by a relative uncertainty of just few %. The smaller agreement in the case of the less concentrated Lithium anyway points out that particular attention must be paid to reduce as much as possible any source of external contamination and highlights the importance of the proper blank subtraction.

Evaluation of the recycle of nitrogen in a succession bean - corn -bean By means of the isotopic method

International Nuclear Information System (INIS)

Duennas Graciela; Munniz, Olegario; Sanchez, Tamara; Gomez, Luis

1999-01-01

To determine the recycle of Nitrogen in a succession bean - corn - bean a was developed I experience under field conditions, on Red Ferralitic soils (Rhodic Ferrasols) with the one I use of the stable isotope 15 Nitrogen

Fertilizer nitrogen leaching in relation to water regime and the fertilizer placement method

International Nuclear Information System (INIS)

Moustafa, A.T.A.; Khadr, M.S.

1983-01-01

A field experiment was conducted at the farm of Sids Experimental Station, Ministry of Agriculture, Middle Egypt, to evaluate the effect of the water regime and fertilizer placement method on the leaching of urea fertilizer under field conditions. Ordinary and heavy irrigations were the water regimes, while side-banding and surface broadcasting were the fertilizer placement methods. Wheat (Giza 158, local variety) was planted, and urea labelled with 15 N at the rate of 100 kg N/ha was added at planting. The data obtained showed that in general the leaching process of urea fertilizer, as evaluated from the amounts of fertilizer nitrogen residues, is not uniform even within replicates. This is despite the fact that the average total amount of fertilizer nitrogen residues in the soil profile to a depth of 125 cm is almost the same in the different treatments. Data also show that the bulk of fertilizer nitrogen residues is accumulated in the surface soil layers, especially at 0-25 cm. Only 10% of the fertilizer nitrogen is detected below 75 cm and up to 125 cm depth of the soil profile. It could be concluded that urea leaching (amount and depth) under these conditions is affected mainly by the soil characteristics, namely soil pores. This is in addition to some other factors that cause variable concentrations in the soil solution leaving the root zone. (author)

A genome-wide identification of chromosomal regions determining nitrogen use efficiency components in wheat (Triticum aestivum L.).

Science.gov (United States)

Cormier, Fabien; Le Gouis, Jacques; Dubreuil, Pierre; Lafarge, Stéphane; Praud, Sébastien

2014-12-01

This study identified 333 genomic regions associated to 28 traits related to nitrogen use efficiency in European winter wheat using genome-wide association in a 214-varieties panel experimented in eight environments. Improving nitrogen use efficiency is a key factor to sustainably ensure global production increase. However, while high-throughput screening methods remain at a developmental stage, genetic progress may be mainly driven by marker-assisted selection. The objective of this study was to identify chromosomal regions associated with nitrogen use efficiency-related traits in bread wheat (Triticum aestivum L.) using a genome-wide association approach. Two hundred and fourteen European elite varieties were characterised for 28 traits related to nitrogen use efficiency in eight environments in which two different nitrogen fertilisation levels were tested. The genome-wide association study was carried out using 23,603 SNP with a mixed model for taking into account parentage relationships among varieties. We identified 1,010 significantly associated SNP which defined 333 chromosomal regions associated with at least one trait and found colocalisations for 39 % of these chromosomal regions. A method based on linkage disequilibrium to define the associated region was suggested and discussed with reference to false positive rate. Through a network approach, colocalisations were analysed and highlighted the impact of genomic regions controlling nitrogen status at flowering, precocity, and nitrogen utilisation on global agronomic performance. We were able to explain 40 ± 10 % of the total genetic variation. Numerous colocalisations with previously published genomic regions were observed with such candidate genes as Ppd-D1, Rht-D1, NADH-Gogat, and GSe. We highlighted selection pressure on yield and nitrogen utilisation discussing allele frequencies in associated regions.

Space-resolved characterization of high frequency atmospheric-pressure plasma in nitrogen, applying optical emission spectroscopy and numerical simulation

International Nuclear Information System (INIS)

Rajasekaran, Priyadarshini; Ruhrmann, Cornelia; Bibinov, Nikita; Awakowicz, Peter

2011-01-01

Averaged plasma parameters such as electron distribution function and electron density are determined by characterization of high frequency (2.4 GHz) nitrogen plasma using both experimental methods, namely optical emission spectroscopy (OES) and microphotography, and numerical simulation. Both direct and step-wise electron-impact excitation of nitrogen emissions are considered. The determination of space-resolved electron distribution function, electron density, rate constant for electron-impact dissociation of nitrogen molecule and the production of nitrogen atoms, applying the same methods, is discussed. Spatial distribution of intensities of neutral nitrogen molecule and nitrogen molecular ion from the microplasma is imaged by a CCD camera. The CCD images are calibrated using the corresponding emissions measured by absolutely calibrated OES, and are then subjected to inverse Abel transformation to determine space-resolved intensities and other parameters. The space-resolved parameters are compared, respectively, with the averaged parameters, and an agreement between them is established. (paper)

INFLUENCE OF MANAGEMENT SYSTEMS ON THE NITROGEN MINERALIZATION AND FERTILIZATION OF SUGARCANE

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Oscar Mauricio Delgado Restrepo

2016-01-01

Full Text Available In Colombia, nitrogen fertilizer recommendations for sugarcane are based on data obtained with the Walkey & Black method, but they do not always result in the best yield. In this sense, the present study aimed to compare the results of the determination of fast mineralizable nitrogen (amino sugars, performed with the Illinois Soil Nitrogen test (ISNT and Direct Steam Distillation method (DSD for nitrogen recommendations for crops. A complete randomized block design was used with six treatments, adding nitrogen through urea and compost to Pachic haplustoll soils in Valle del Cauca with organic and conventional production systems that were evaluated from 2011 to 2013. The results showed that higher nitrogen mineralization was estimated using ISNT and DSD methodologies than with the Walkley-Black method, and that its content was different depending on the operating system. The best methodology The best methodology that quantified mineralization was Direct Steam Distillation (DSD; however for conventional systems sugarcane was Illinois Soil Nitrogen Test (ISNT, showing differences for the variables associated with the production and yield between the tested systems.

Studies of the efficiency of nitrogen placement methods and slow release nitrogen fertilizers for rice and wheat, using N-15 labelled fertilizers

International Nuclear Information System (INIS)

Shaukat, A.

1979-12-01

A series of experiments with rice and wheat were carried out to study the efficiency of nitrogen placement methods and slow-release nitrogen fertilizers for these two crops using N-15-labelled fertilizer. The results show that (1) reduced N levels, of the order of 75 percent of the full recommended dose, are equally efficient as the full dose for wheat. The yield of rice grain increased with the increased dose of nitrogen; (2) Point placement of fertilizers for rice was superior to broadcast application in terms of uptake and yield. For optimum yield of wheat grain, urea should perferably be applied as a single dose banded between the rows at 5 cm depth or by broadcasting and incorporation in the soil at the time of sowing; (3) Sulphur-coated urea (SCU) at a comparable dose and mode of application gave better yields of rice grain than the application of urea and IBDU (Isobutylidine Diurea); (4) More nitrogen was taken up by wheat when SCU was applied. The best uptake was when it was applied half at sowing and half at tillering. The nitrogen uptake from the SCU by point placement was better for rice plants than broadcast application and was higher in magnitude than the IBDU

Dissolved organic nitrogen recalcitrance and bioavailable nitrogen quantification for effluents from advanced nitrogen removal wastewater treatment facilities.

Science.gov (United States)

Fan, Lu; Brett, Michael T; Jiang, Wenju; Li, Bo

2017-10-01

The objective of this study was to determine the composition of nitrogen (N) in the effluents of advanced N removal (ANR) wastewater treatment plants (WWTPs). This study also tested two different experimental protocols for determining dissolved N recalcitrance. An analysis of 15 effluent samples from five WWTPs, showed effluent concentrations and especially effluent composition varied greatly from one system to the other, with total nitrogen (TN) ranging between 1.05 and 8.10 mg L -1 . Nitrate (NO 3 - ) accounted for between 38 ± 32% of TN, and ammonium accounted for a further 29 ± 28%. All of these samples were dominated by dissolved inorganic nitrogen (DIN; NO 3 -  + NH 4 + ), and uptake experiments indicated the DIN fraction was as expected highly bioavailable. Dissolved organic N (DON) accounted for 20 ± 11% for the total dissolved N in these effluents, and uptake experiments indicated the bioavailability of this fraction varied between 27 ± 26% depending on the WWTP assessed. These results indicate near complete DIN removal should be the primary goal of ANR treatment systems. The comparison of bioavailable nitrogen (BAN) quantification protocols showed that the dissolved nitrogen uptake bioassay approach was clearly a more reliable way to determine BAN concentrations compared to the conventional cell yield protocol. Moreover, because the nitrogen uptake experiment was much more sensitive, this protocol made it easier to detect extrinsic factors (such as biological contamination or toxicity) that could affect the accuracy of these bioassays. Based on these results, we recommend the nitrogen uptake bioassay using filtered and autoclaved samples to quantify BAN concentrations. However, for effluent samples indicating toxicity, algal bioassays will not accurately quantify BAN. Copyright © 2017 Elsevier Ltd. All rights reserved.

The nitrogen footprint tool network: a multi-institution program to reduce nitrogen pollution

Science.gov (United States)

Anthropogenic sources of reactive nitrogen have local and global impacts on air and water quality and detrimental effects on human and ecosystem health. This paper uses the nitrogen footprint tool (NFT) to determine the amount of nitrogen (N) released as a result of institutional...

Evaluation of Kjeldahl digestion method

International Nuclear Information System (INIS)

Amin, M.; Flowers, T.H.

2004-01-01

The evaluation of the Kjeldahl digestion method was investigated by comparing measured values of total nitrogen, phosphorus and potassium using three salt and catalyst mixture in Standard Kjeldahl digestion method and Salicyclic acid Modification method with certified values of plant material as well as comparison was made for determination of total nitrogen from steam distillation method verses the Technicon Auto-analyzer, and phosphorus Ascorbic acid/Molybdate method verses Molybdate/ Metavanadate method on the Technicon Auto-Analyzer. The 1 g salt/catalyst mixture recovered less nitrogen than the 2.5 g in the standard Kjeldahl method due to the lower temperature and incomplete digestion in both plant and soil samples. The 2.5 g catalyst mixture partially recovered nitrate in the standard Kjeldahl method and the salicylic acid modification fail to recover all over nitrate in plant material. Use of 2.5 g salt catalyst mixture and selenium appears to promote nitrogen losses in salicylic acid modification method but not in the standard Kjeldahl method of digestion for soil samples. No interference of selenium or copper was observed in Nitrogen and Phosphorus on calorimetric determination. The standard Kjeldahl method with 2.5 g of salt/catalyst mixture of sodium sulphate copper sulphate (10:1) in 5 ml sulfuric acid were found suitable for determination of total Nitrogen, phosphorus and potassium. The steam distillation and the Technicon Auto-Analyzer technique measure similar amounts of ammonium nitrogen. However, the Technicon Auto analyzer technique is easier, rapid, higher degree of reproducibility, precise, accurate, reliable and free from human error. The amount of phosphorus measured by the Ascorbic acid/Molybdate method was more accurate than by the Molybdate/Metavanadate method on Technicon Auto-Analyzer. (author)

Ammonia Nitrogen Added to Diets Deficient in Dispensable Amino Acid Nitrogen Is Poorly Utilized for Urea Production in Growing Pigs.

Science.gov (United States)

Mansilla, Wilfredo D; Silva, Kayla E; Zhu, Cuilan L; Nyachoti, Charles M; Htoo, John K; Cant, John P; de Lange, Cornelis Fm

2017-12-01

Background: Including ammonia in low-crude protein (CP) diets deficient in dispensable amino acid (DAAs) increases nitrogen retention in growing pigs. Objective: We investigated the absorption and metabolism of dietary ammonia nitrogen in the portal-drained viscera (PDV) and liver of pigs fed a diet deficient in DAA nitrogen. Methods: Eight pigs with an initial mean ± SD body weight (BW) of 26.5 ± 1.4 kg were surgically fitted with 4 catheters each (portal, hepatic and mesenteric veins, and carotid artery). The pigs were fed (2.8 × 191 kcal/kg BW 0.60 ), for 7 d and every 8 h, a diet deficient in DAA nitrogen supplemented with increasing amounts of ammonia nitrogen (CP: 7.76%, 9.27%, and 10.77%; indispensable amino acid nitrogen:total nitrogen ratio: 0.71, 0.59, and 0.50 for control and low- and high-ammonia diets, respectively). The treatment sequence was based on a Latin square design with 3 consecutive periods. On the last day of each period, blood flows in the portal and hepatic veins were determined with a continuous infusion of ρ-amino hippuric acid into the mesenteric vein. Serial blood samples were taken to determine ammonia and urea nitrogen concentration. Net balances of ammonia and urea nitrogen were calculated for the PDV and liver. Results: Cumulative (8 h) ammonia nitrogen appearance in the portal vein increased ( P ≤ 0.05) with ammonia intake (433, 958, and 1629 ± 60 mg ammonia nitrogen/meal for control and low- and high-ammonia diets, respectively). The cumulative hepatic uptake of ammonia nitrogen increased ( P ≤ 0.05) with ammonia nitrogen supply. The cumulative urea nitrogen appearance in the hepatic vein tended to increase ( P ≤ 0.10) only in high-ammonia treatment (-92.5, -59.4, and 209.7 ± 92 mg urea nitrogen/meal for control and low- and high-ammonia diets, respectively) and, relative to the control diet, represented -6.0% and 11% of ammonia nitrogen intake. Conclusion: Dietary ammonia nitrogen is poorly utilized for urea

System and method for controlling ammonia levels in a selective catalytic reduction catalyst using a nitrogen oxide sensor

Science.gov (United States)

None

2017-07-25

A system according to the principles of the present disclosure includes an air/fuel ratio determination module and an emission level determination module. The air/fuel ratio determination module determines an air/fuel ratio based on input from an air/fuel ratio sensor positioned downstream from a three-way catalyst that is positioned upstream from a selective catalytic reduction (SCR) catalyst. The emission level determination module selects one of a predetermined value and an input based on the air/fuel ratio. The input is received from a nitrogen oxide sensor positioned downstream from the three-way catalyst. The emission level determination module determines an ammonia level based on the one of the predetermined value and the input received from the nitrogen oxide sensor.

Rapid estimation of organic nitrogen in oil shale waste waters

Energy Technology Data Exchange (ETDEWEB)

Jones, B.M.; Daughton, C.G.; Harris, G.J.

1984-04-01

Many of the characteristics of oil shale process waste waters (e.g., malodors, color, and resistance to biotreatment) are imparted by numerous nitrogenous heterocycles and aromatic amines. For the frequent performance assessment of waste treatment processes designed to remove these nitrogenous organic compounds, a rapid and colligative measurement of organic nitrogen is essential. Quantification of organic nitrogen in biological and agricultural samples is usually accomplished using the time-consuming, wet-chemical Kjeldahl method. For oil shale waste waters, whose primary inorganic nitorgen constituent is amonia, organic Kjeldahl nitrogen (OKN) is determined by first eliminating the endogenous ammonia by distillation and then digesting the sample in boiling H/sub 2/SO/sub 4/. The organic material is oxidized, and most forms of organically bound nitrogen are released as ammonium ion. After the addition of base, the ammonia is separated from the digestate by distillation and quantified by acidimetric titrimetry or colorimetry. The major failings of this method are the loss of volatile species such as aliphatic amines (during predistillation) and the inability to completely recover nitrogen from many nitrogenous heterocycles (during digestion). Within the last decade, a new approach has been developed for the quantification of total nitrogen (TN). The sample is first combusted, a

Development of a new microextraction method based on elevated temperature dispersive liquid-liquid microextraction for determination of triazole pesticides residues in honey by gas chromatography-nitrogen phosphorus detection.

Science.gov (United States)

Farajzadeh, Mir Ali; Mogaddam, Mohammad Reza Afshar; Ghorbanpour, Houshang

2014-06-20

In the present study, a rapid, highly efficient, and reliable sample preparation method named "elevated temperature dispersive liquid-liquid microextraction" followed by gas chromatography-nitrogen-phosphorus detection was developed for the extraction, preconcentration, and determination of five triazole pesticides (penconazole, hexaconazole, diniconazole, tebuconazole, and difenoconazole) in honey samples. In this method the temperature of high-volume aqueous phase was adjusted at an elevated temperature and then a disperser solvent containing an extraction solvent was rapidly injected into the aqueous phase. After cooling to room temperature, the phase separation was accelerated by centrifugation. Various parameters affecting the extraction efficiency such as type and volume of the extraction and disperser solvents, temperature, salt addition, and pH were evaluated. Under the optimum extraction conditions, the method resulted in low limits of detection and quantification within the range 0.05-0.21ngg(-1) in honey (15-70ngL(-1) in solution) and 0.15-1.1ngg(-1) in honey (45-210ngL(-1) in solution), respectively. Enrichment factors and extraction recoveries were in the ranges of 1943-1994 and 97-100%, respectively. The method precision was evaluated at 1.5ngg(-1) of each analyte, and the relative standard deviations were found to be less than 4% for intra-day (n=6) and less than 6% for inter-days. The method was successfully applied to the analysis of honey samples and difenoconazole was determined at ngg(-1) levels. Copyright © 2014 Elsevier B.V. All rights reserved.

Simple, sensitive nitrogen analyzer based on pulsed miniplasma source emission spectrometry

International Nuclear Information System (INIS)

Jin Zhe; Duan Yixiang

2003-01-01

The development of pulsed miniplasma source emission spectrometry for trace nitrogen determination in inert gases is described in this article. The instrument consists of a pulsed miniplasma source generated by an in-house fabricated portable high-voltage supply, an optical beam collection system, an integrated small spectrometer with a charge-coupled-device detector, an interface card, and a notebook computer for controlling spectrometer parameters and signal processing. Trace nitrogen in the inert gases, such as helium and argon, was determined by monitoring the emission intensities from nitrogen molecules at 357 and 337 nm. The analytical performance was examined under various experimental conditions. The system has a detection limit of about 15 ppb (v/v) for nitrogen in helium with a relative standard deviation of 1.5%. The newly developed instrument offers a simple, low-cost, and sensitive method for continuously monitoring trace nitrogen in high-purity inert gases

Synthesis of nitrogen-doped and amino acid-functionalized graphene quantum dots from glycine, and their application to the fluorometric determination of ferric ion

International Nuclear Information System (INIS)

Li, Linbo; Li, Lin; Wang, Chao; Liu, Kangyu; Zhu, Ruohua; Qiang, Hong; Lin, Yuqing

2015-01-01

We report on a single-step thermolysis strategy to prepare highly luminescent nitrogen-doped and amino acid-functionalized graphene quantum dots (NA-GQDs) by using glycine as both carbon and nitrogen source. The NA-GQDs display an excitation wavelength-dependent fluorescence with maximum excitation and emission wavelengths of 380 and 450 nm, respectively, and a quantum yield of ∼16 %. Fluorescence is quenched by Fe(III) and Hg(II), and the effect was used to develop a method for the determination of Fe(III). Quenching by Fe(III) is attributed to its higher thermodynamic affinity (compared to other transition-metal ions) for the ligands on the GQDs in which nitrogen atoms mainly act as the chelating atoms. A linear relationship was observed between fluorescence intensity and the concentration of Fe(III) over the 0.5 μM to 0.5 mM range. The detection limit is 0.1 μM. (author)

Simultaneous determination of boron, carbon and nitrogen in silicon by deuteron activation analysis

International Nuclear Information System (INIS)

He, Shiyu; Wang, Yinsong; Jin, Baikang; Hua, Zhifen; Zhao, Kaihua

1984-01-01

The paper describes simultaneous determination of trace quantities of B, C and N in semiconductor silicon by nuclear reaction of 10 B(d, n) 11 C(T 1/2 = 20.3 min), 11 B(d, 2n) 11 C, 12 C(d, n) 13 N(T 1/2 = 9.96 min) and 14 N(d, n) 15 O(T 1/2 = 2.03 min) with deuterons from a 1.2 m cyclotron in our institute. An inert-gas fusion technique is adopted for rapid radiochemical separation after irradiation of the samples. 11 C, 13 N and 15 O are absorbed in ascarite 5A molecular sieve cooled in liquid nitrogen and Hopcalite reagent at a temperature of 650 deg C respectively. Positron Annihilation events of each produced nucleus are counted by a γ - γ coincidence measuring system. B, C and N contents of about several ten parts per billion in silicon are then calculated simultaneously by a relatively quantitative method. Relative standard deviation for C, B and N are less than +-50% respectively. This method is simple, rapid and sensitive for estimating light element content in silicon material. (author)

Determination of Optimum Nitrogen and Potassium Levels for potato Production in Central high lands of Ethiopia

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Shunka Egata

2017-02-01

Full Text Available To determine the required levels of nitrogen and potassium, an experiment was conducted at Holetta Agricultural Research Center and Jeldu sub Center from 2014-2015 using three factors (Jalenie, Gudenie and Belete potato varies; 87, 110, 133kg/ha nitrogen rates and 0, 34.5, 69, 103.5kg/ha potassium in the form of K2O levels and as a completely randomized block design arrangement with three replications. In each location every year the 36 treatments (4 potassium oxide levels x 3 nitrogen levels x 3 varieties were assigned in random combinations to 36 plots of one block in a random case which was replicated in to two additional blocks of different randomizations in order to make total of three replications/blocks. Data were analyzed by SAS software Version 9.2. Potassium rates significantly affected the total yield and marketable yield as compared to the control treatment. Application of potassium at 103.5 kg/ha produced significantly a higher marketable yield than all rates. As compared to Jeldu, the Holetta location produced the maximum highly significant yield and yield component. Interaction of potassium and nitrogen fertilizers affected marketable tuber numbers and plant height significantly. In 2014, Belete produced the highest (27.31 ton/ha marketable yield at an application of 34.5 kg/ha potassium and 110 kg/ha nitrogen while Gudenie produced the highest (30.53 ton/ha marketable yield at an application of 69 kg/ ha potassium and 110 kg/ha nitrogen rates in 2015. It is better to apply 69 kg/ha potassium and 110 kg/ha nitrogen to potato production for reasonable yield at sites similar to experimental locations. It can be concluded that, interaction of nitrogen and potassium rates significantly affected plant height and marketable tuber numbers.

Effects of nitrogen rate and application method on early production and fruit quality in highbush blueberry

Science.gov (United States)

A field study was conducted to examine the effects of nitrogen (N) rate and method of N fertilizer application on growth, yield, and fruit quality in highbush blueberry (Vaccinium corymbosum L.) during the first 4 years after planting in south-coastal BC. Nitrogen was applied at 0-150% of current pr...

Nitrogen doped silicon-carbon multilayer protective coatings on carbon obtained by TVA method

Science.gov (United States)

Ciupina, Victor; Vasile, Eugeniu; Porosnicu, Corneliu; Lungu, Cristian P.; Vladoiu, Rodica; Jepu, Ionut; Mandes, Aurelia; Dinca, Virginia; Caraiane, Aureliana; Nicolescu, Virginia; Cupsa, Ovidiu; Dinca, Paul; Zaharia, Agripina

2017-08-01

Protective nitrogen doped Si-C multilayer coatings on carbon, used to improve the oxidation resistance of carbon, were obtained by Thermionic Vacuum Arc (TVA) method. The initial carbon layer having a thickness of 100nm has been deposed on a silicon substrate in the absence of nitrogen, and then a 3nm Si thin film to cover carbon layer was deposed. Further, seven Si and C layers were alternatively deposed in the presence of nitrogen ions, each having a thickness of 40nm. In order to form silicon carbide at the interface between silicon and carbon layers, all carbon, silicon and nitrogen ions energy has increased up to 150eV . The characterization of microstructure and electrical properties of as-prepared N-Si-C multilayer structures were done using Transmission Electron Microscopy (TEM, STEM) techniques, Thermal Desorption Spectroscopy (TDS) and electrical measurements. Oxidation protection of carbon is based on the reaction between oxygen and silicon carbide, resulting in SiO2, SiO and CO2, and also by reaction involving N, O and Si, resulting in silicon oxynitride (SiNxOy) with a continuously variable composition, and on the other hand, since nitrogen acts as a trapping barrier for oxygen. To perform electrical measurements, 80% silver filled two-component epoxy-based glue ohmic contacts were attached on the N-Si-C samples. Electrical conductivity was measured in constant current mode. The experimental data show the increase of conductivity with the increase of the nitrogen content. To explain the temperature behavior of electrical conductivity we assumed a thermally activated electric transport mechanism.

The Effects of Source and Rate of Nitrogen Fertilizer and Irrigation on Nitrogen Uptake of Silage Corn and Residual Soil Nitrate

Directory of Open Access Journals (Sweden)

M. A. Khodshenas

2016-09-01

oven at 70ºC for at least 3 days before weighting. Total N concentration in the plant samples were determined using kjeldahl method. Nitrogen uptake by plants was calculated based on the total N concentration in plants multiplied by dry matter. Residual nitrate concentrations were determined in soil samples (0-30 and 30-60 cm depths by diazo method. Combined analysis of variance was accomplished using the MSTAT-C software. Mean comparisons were done using Duncan multiple rang test (DMRT. Results: The results showed that the main effect of water stress on dry matter yield was negative and significant (P

Characterization of transient discharges under atmospheric-pressure conditions applying nitrogen photoemission and current measurements

International Nuclear Information System (INIS)

Keller, Sandra; Rajasekaran, Priyadarshini; Bibinov, Nikita; Awakowicz, Peter

2012-01-01

The plasma parameters such as electron distribution function and electron density of three atmospheric-pressure transient discharges namely filamentary and homogeneous dielectric barrier discharges in air, and the spark discharge of an argon plasma coagulation (APC) system are determined. A combination of numerical simulation as well as diagnostic methods including current measurement and optical emission spectroscopy (OES) based on nitrogen emissions is used. The applied methods supplement each other and resolve problems, which arise when these methods are used individually. Nitrogen is used as a sensor gas and is admixed in low amount to argon for characterizing the APC discharge. Both direct and stepwise electron-impact excitation of nitrogen emissions are included in the plasma-chemical model applied for characterization of these transient discharges using OES where ambiguity arises in the determination of plasma parameters under specific discharge conditions. It is shown that the measured current solves this problem by providing additional information useful for the determination of discharge-specific plasma parameters. (paper)

Determination of symbiotic nitrogen fixation by labelling the soil atmosphere with sup(15)N sub(2) at low isotope enrichment

International Nuclear Information System (INIS)

Trivelin, P.C.O.

1982-01-01

A direct method to determine the total symbiotic nitrogen fixation during the leguminous plants cycles has been, developed, by labelling the soil atmosphere with sup(15)N sub(2) at low isotope enrichment, of about 1 atom % excess. The soil explored by the root system of leguminous plants was confined by means of a chamber in the field and by sealed pots in greenhouse experiments in order to maintain the soil air labelled with sup(15)N sub(2). The average sup(15)N concentration in the soil atmosphere, necessary to calculate dinitrogen fixation, was obtained by integration of the exponential functions of isotope dilution. Those functions were obtained by periodic sampling and analysis of the N sub(2) in the soil atmosphere. The field experiment with labelled atmosphere was carried out from the 22 sup(nd) to the 31 sup(st) day of the bean crop cycle and 5.5 mg N/plant (24% of total plant N) was derived from fixation. In pot experiments, under greenhouse conditions, integrated determination of fixation was made in Phaseolus beans (from the 19 sup(th) to the 67 sup(th) day from planting) and in soybeans (from the 24 sup(th) to the 70 sup(th) day from planting). The soil atmosphere was labelled with sup(15)N sub(2) in both cases. Average fixation obtained for Phaseolus beans was 80 mg N/plant (65% of total plant N) and for soybeans 265 mg N/plant (71% of total plant N). Evaluation of the basic concept of the isotope dilution method to determine nitrogen fixation in pots experiments, as proposed by Fried and Middelboe (1977) has also been made in the present paper. Simultaneous determinations of fixation in soybeans, using the isotope dilution method of Fried and Middelboe, natural variation of the sup(15)N/ sup(14)N ratios, and total-N differences, indicated the same results for pot experiments, harvested at the end of the plant cycle. (author)

Growth and yield of cucumber as influenced by compost and nitrogen fertilizer in sandy soils using the nuclear technique for determination of nitrogen

International Nuclear Information System (INIS)

El-Sherif, M.F.A.

2005-01-01

this study was carried out during the period from 2002 to 2003 seasons, at the department of plant research, Nuclear Research Center (NRC,) Atomic Energy Authority (AEA), Egypt, on cucumber plants c.v. dp007 F1 (wafer). the main objective of this work was to study the effect of compost type, application level and nitrogen rate on vegetative growth, chemical composition, early and total yield and to determine the fertilizer nitrogen uptake and utilization by the cucumber plant and its parts, i.e., shoots and fruits . results revealed that the sugar cane bagasse compost (SC) gave a significantly higher response with most vegetative growth expressed as plant length, leaf number and dry weight of cucumber plant, compared with beet compost (BC). the application of compost from 2 up to 6 ton/fed

Method of removing oxides of sulfur and oxides of nitrogen from exhaust gases

Science.gov (United States)

Walker, Richard J.

1986-01-01

A continuous method is presented for removing both oxides of sulfur and oxides of nitrogen from combustion or exhaust gases with the regeneration of the absorbent. Exhaust gas is cleaned of particulates and HCl by a water scrub prior to contact with a liquid absorbent that includes an aqueous solution of bisulfite and sulfite ions along with a metal chelate, such as, an iron or zinc aminopolycarboxylic acid. Following contact with the combustion gases the spent absorbent is subjected to electrodialysis to transfer bisulfite ions into a sulfuric acid solution while splitting water with hydroxide and hydrogen ion migration to equalize electrical charge. The electrodialysis stack includes alternate layers of anion selective and bipolar membranes. Oxides of nitrogen are removed from the liquid absorbent by air stripping at an elevated temperature and the regenerated liquid absorbent is returned to contact with exhaust gases for removal of sulfur oxides and nitrogen oxides.

Reference material certification of chinese cabbage composition for selenium, nitrogen, phosphorus and potassium content

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D. A. Chupakhin

2016-01-01

Full Text Available Rationale. The reference material of composition with the established metrological characteristics including a certified value and an expanded uncertainty is necessary to ensure an effective accuracy and precision control of results of element composition determination in food ingredients and products. This paper represents the development of a reference material of food crop composition for selenium, nitrogen, phosphorus and potassium content. Methods. To identify the selenium the hybrid atomic absorption method was used, to identify the nitrogen and phosphorus the photometric method was used, to determine the potassium flame-photometric method was used. When determining the metrological characteristics of the reference material the Russian national instructions and recommendations MI 3174-2009 and P 50.2.058-2007 were applied. Results. Based on the research findings the reference material of Chinese cabbage composition with a certified value and an expanded uncertainty was developed: for selenium 0.044 ± 0.017 mg/kg; for nitrogen 4.09 ± 0.27 %; for phosphorus 0.69 ± 0.14 %; for potassium 2.87 ± 0.22 %.

Determination of prilocaine HCl in bulk drug and pharmaceutical formulation by GC-NPD method

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Atila Alptug

2013-01-01

Full Text Available The novel analytical method was developed and validated for determination of prilocaine HCl in bulk drug and pharmaceutical formulation by gas chromatography-nitrogen phosphorus detection (GC-NPD. The chromatographic separation was performed using a HP-5MS column. The calibration curve was linear over the concentration range of 40-1000 ng ml-1 with a correlation coefficient of 0.9998. The limits of detection (LOD and quantification (LOQ of method were 10 ng ml-1 and 35 ng ml-1, respectively. The within-day and between-day precision, expressed as the percent relative standard deviation (RSD% was less than 5.0%, and accuracy (percent relative error was better than 4.0%. The developed method can be directly and easily applied for determination of prilocaine HCl in bulk drug and pharmaceutical formulation using internal standard methodology.

Effect of nitrogen source and acclimatization on specific growth rates of microalgae determined by a high-throughput in vivo microplate autofluorescence method

DEFF Research Database (Denmark)

Podevin, Mike; De Francisci, Davide; Holdt, Susan Løvstad

2015-01-01

SGRs of the second and third cultivations. ANOVA of SGRs in the acclimatized second and third cultivations revealed preferences for nitrogen sources among most of the algae; C. vulgaris preferred sodiumnitrate over other nitrogen sources, A. protothecoides adapted to urea after no growth in the first...

A novel method for observation by unaided eyes of nitrogen ion tracks and angular distribution in a plasma focus device using 50 Hz–HV electrochemically-etched polycarbonate detectors

International Nuclear Information System (INIS)

Sohrabi, M.; Habibi, M.; Roshani, G.H.; Ramezani, V.

2012-01-01

A novel ion detection method has been developed and studied in this paper for the first time to detect and observe tracks of nitrogen ions and their angular distribution by unaided eyes in the Amirkabir 4 kJ plasma focus device (PFD). The method is based on electrochemical etching (ECE) of nitrogen ion tracks in 1 mm thick large area polycarbonate (PC) detectors. The ECE method employed a specially designed and constructed large area ECE chamber by applying a 50 Hz–high voltage (HV) generator under optimized ECE conditions. The nitrogen ion tracks and angular distribution were efficiently (constructed for this study) amplified to a point observable by the unaided eyes. The beam profile and angular distribution of nitrogen ion tracks in the central axes of the beam and two- and three-dimensional iso-ion track density distributions showing micro-beam spots were determined. The distribution of ion track density along the central axes versus angular position shows double humps around a dip at the 0° angular positions. The method introduced in this paper proved to be quite efficient for ion beam profile and characteristic studies in PFDs with potential for ion detection studies and other relevant dosimetry applications.

Methods for determination of biomethane potential of feedstocks: a review

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Raphael Muzondiwa Jingura

2017-06-01

Full Text Available Biogas produced during anaerobic digestion (AD of biodegradable organic materials. AD is a series of biochemical reactions in which microorganisms degrade organic matter under anaerobic conditions. There are many biomass resources that can be degraded by AD to produce biogas. Biogas consists of methane, carbon dioxide, and trace amounts of other gases. The gamut of feedstocks used in AD includes animal manure, municipal solid waste, sewage sludge, and various crops. Several factors affect the potential of feedstocks for biomethane production. The factors include nutrient content, total and volatile solids (VS content, chemical and biological oxygen demand, carbon/nitrogen ratio, and presence of inhibitory substances. The biochemical methane potential (BMP, often defined as the maximum volume of methane produced per g of VS substrate provides an indication of the biodegradability of a substrate and its potential to produce methane via AD. The BMP test is a method of establishing a baseline for performance of AD. BMP data are useful for designing AD parameters in order to optimise methane production. Several methods which include experimental and theoretical methods can be used to determine BMP. The objective of this paper is to review several methods with a special focus on their advantages and disadvantages. The review shows that experimental methods, mainly the BMP test are widely used. The BMP test is credited for its reliability and validity. There are variants of BMP assays as well. Theoretical models are alternative methods to estimate BMP. They are credited for being fast and easy to use. Spectroscopy has emerged as a new experimental tool to determine BMP. Each method has its own advantages and disadvantages with reference to efficacy, time, and ease of use. Choosing a method to use depends on various exigencies. More work needs to be continuously done in order to improve the various methods used to determine BMP.

Nitrogen concentration estimation with hyperspectral LiDAR

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O. Nevalainen

2013-10-01

Full Text Available Agricultural lands have strong impact on global carbon dynamics and nitrogen availability. Monitoring changes in agricultural lands require more efficient and accurate methods. The first prototype of a full waveform hyperspectral Light Detection and Ranging (LiDAR instrument has been developed at the Finnish Geodetic Institute (FGI. The instrument efficiently combines the benefits of passive and active remote sensing sensors. It is able to produce 3D point clouds with spectral information included for every point which offers great potential in the field of remote sensing of environment. This study investigates the performance of the hyperspectral LiDAR instrument in nitrogen estimation. The investigation was conducted by finding vegetation indices sensitive to nitrogen concentration using hyperspectral LiDAR data and validating their performance in nitrogen estimation. The nitrogen estimation was performed by calculating 28 published vegetation indices to ten oat samples grown in different fertilization conditions. Reference data was acquired by laboratory nitrogen concentration analysis. The performance of the indices in nitrogen estimation was determined by linear regression and leave-one-out cross-validation. The results indicate that the hyperspectral LiDAR instrument holds a good capability to estimate plant biochemical parameters such as nitrogen concentration. The instrument holds much potential in various environmental applications and provides a significant improvement to the remote sensing of environment.

DATING: A computer code for determining allowable temperatures for dry storage of spent fuel in inert and nitrogen gases

International Nuclear Information System (INIS)

Simonen, E.P.; Gilbert, E.R.

1988-12-01

The DATING (Determining Allowable Temperatures in Inert and Nitrogen Gases) code can be used to calculate allowable initial temperatures for dry storage of light-water-reactor spent fuel. The calculations are based on the life fraction rule using both measured data and mechanistic equations as reported by Chin et al. (1986). The code is written in FORTRAN and utilizes an efficient numerical integration method for rapid calculations on IBM-compatible personal computers. This report documents the technical basis for the DATING calculations, describes the computational method and code statements, and includes a user's guide with examples. The software for the DATING code is available through the National Energy Software Center operated by Argonne National Laboratory, Argonne, Illinois 60439. 5 refs., 8 figs., 5 tabs

Isotopic dilution methods to determine the gross transformation rates of nitrogen, phosphorus, and sulfur in soil: a review of the theory, methodologies, and limitations

International Nuclear Information System (INIS)

Di, H. J.; Cameron, K. C.; McLaren, R. G.

2000-01-01

The rates at which nutrients are released to, and removed from, the mineral nutrient pool are important in regulating the nutrient supply to plants. These nutrient transformation rates need to be taken into account when developing nutrient management strategies for economical and sustainable production. A method that is gaining popularity for determining the gross transformation rates of nutrients in the soil is the isotopic dilution technique. The technique involves labelling a soil mineral nutrient pool, e.g. NH 4 + , NO 3 - , PO 4 3- , or SO 4 2- , and monitoring the changes with time of the size of the labelled nutrient pool and the excess tracer abundance (atom %, if stable isotope tracer is used) or specific activity (if radioisotope is used) in the nutrient pool. Because of the complexity of the concepts and procedures involved, the method has sometimes been used incorrectly, and results misinterpreted. This paper discusses the isotopic dilution technique, including the theoretical background, the methodologies to determine the gross flux rates of nitrogen, phosphorus, and sulfur, and the limitations of the technique. The assumptions, conceptual models, experimental procedures, and compounding factors are discussed. Possible effects on the results by factors such as the uniformity of tracer distribution in the soil, changes in soil moisture content, substrate concentration, and aeration status, and duration of the experiment are also discussed. The influx and out-flux transformation rates derived from this technique are often contributed by several processes simultaneously, and thus cannot always be attributed to a particular nutrient transformation process. Despite the various constraints or possible compounding factors, the technique is a valuable tool that can provide important quantitative information on nutrient dynamics in the soil-plant system. Copyright (2000) CSIRO Publishing

Nitrogen concentrations in mosses indicate the spatial distribution of atmospheric nitrogen deposition in Europe

International Nuclear Information System (INIS)

Harmens, H.; Norris, D.A.; Cooper, D.M.; Mills, G.; Steinnes, E.; Kubin, E.; Thoeni, L.; Aboal, J.R.; Alber, R.; Carballeira, A.; Coskun, M.; De Temmerman, L.; Frolova, M.; Gonzalez-Miqueo, L.

2011-01-01

In 2005/6, nearly 3000 moss samples from (semi-)natural location across 16 European countries were collected for nitrogen analysis. The lowest total nitrogen concentrations in mosses ( 2 = 0.91) linear relationship was found between the total nitrogen concentration in mosses and measured site-specific bulk nitrogen deposition rates. The total nitrogen concentrations in mosses complement deposition measurements, helping to identify areas in Europe at risk from high nitrogen deposition at a high spatial resolution. - Highlights: → Nitrogen concentrations in mosses were determined at ca. 3000 sites across Europe. → Moss concentrations were compared with EMEP modelled nitrogen deposition. → The asymptotic relationship for Europe showed saturation at ca. 15 kg N ha -1 y -1 . → Linear relationships were found with measured nitrogen deposition in some countries. → Moss concentrations complement deposition measurements at high spatial resolution. - Mosses as biomonitors of atmospheric nitrogen deposition in Europe.

Measurement of nitrogen dioxide in the air

Energy Technology Data Exchange (ETDEWEB)

Shaw, J T

1967-01-01

The Hersch electrolytic nitrogen dioxide generator has been used to provide accurately known weights of nitrogen dioxide and hence to evaluate a calibration factor for the colorimetric reagent described by Saltaman for the determination of this gas. A method of testing whether the electrolytic generator was giving a quantitative output of NO/sub 2/ is described. The work has confirmed Saltman's value of 0.72 for the calibration factor. An assertion that the calibration factor is dependent on the concentration of nitrogen dioxide sampled, is re-examined and dismissed, the observations being re-interpreted on a simple basis. A tentative suggestion is made as to why, in recent work by Stratmann and Buck, a calibration factor equal to unity has been found. 8 references, 4 figures, 1 table.

A method for measuring element fluxes in an undisturbed soil: nitrogen and carbon from earthworms

International Nuclear Information System (INIS)

Bouche, M.B.

1984-01-01

Data on chemical cycles, as nitrogen or carbon cycles, are extrapolated to the fields or ecosystems without the possibility for checking conclusions; i.e. from scientific knowledge (para-ecology). A new method, by natural introduction of an earthworm compartment into an undisturbed soil, with earthworms labelled both by isotopes ( 15 N, 14 C) and by staining is described. This method allows us to measure fluxes of chemicals. The first results, gathered during the improvement of the method in partly artificial conditions, are cross-checked with other data given by direct observation in the field. Measured flux (2.2 mg N/g fresh mass empty gut/day/15 0 C) is far more important than para-ecological estimations; animal metabolism plays directly an important role in nitrogen and carbon cycles. (author)

Microbial incorporation of nitrogen in stream detritus

Science.gov (United States)

Diane M. Sanzone; Jennifer L. Tank; Judy L. Meyer; Patrick J. Mulholland; Stuart E.G. Findlay

2001-01-01

We adapted the chloroform fumigation method to determine microbial nitrogen (N) and microbial incorporation of 15N on three common substrates [leaves, wood and fine benthic organic matter (FBOM)] in three forest streams. We compared microbial N and 15 content of samples collected during a 6-week15N-NH...

Problems of Nitrogen at Central Municipal Water Works in Ostrava

Directory of Open Access Journals (Sweden)

Praus Petr

2003-09-01

Full Text Available Nitrogen is very important nutrient and must be removed during wastewater treatment process. The presented article describes the situation of nitrogen removal at the Central Municipal Water Works in Ostrava. At present, this biological sewage plant operates with only 45% nitrogen removal efficiency. The current three corridor denitrification-nitrification (D-N system is planed to be reconstructed. One of several solution is modification of the activation tank into four step D-N system that could be completed by postdenitrification in the redundant clarifiers.In this paper the analytical methods, used for determination of nitrogen compounds in waste waters, are described as well. Only sufficiently precise and accurate methods must be selected and that is why the standardized or fully validated procedures are preferred. Laboratory results are used for monitoring of treatment process and for making of important technological decisions. For this purpose, introduction of the quality control and quality assurance system into laboratory practise is desired.

Method for the production of nitrogen and hydrogen in a fuel cell

NARCIS (Netherlands)

Hemmes, K.

2007-01-01

The invention relates to a method for the production of nitrogen and hydrogen in a fuel cell with an anode and a cathode, comprising the steps of inducing a combustion in a fuel cell, wherein a fuel is supplied to the anode, and air is supplied to the cathode, and with oxygen in the air being

The study on effect of zeolite on nitrogen use efficiency of corn by 15N-isotope dilution method

International Nuclear Information System (INIS)

Li Changhong; Li Huaxing; Zhang Xinming; Liu Yuanjin

2002-01-01

A pot experiment was carried out to study the effect of natural zeolite on nitrogen use efficiency of corn by using 15 N-isotope dilution method. The results showed that application of zeolite could improve the corn growth and enhance the biomass of the corn seedling. By using zeolite, nitrogen use efficiency (NUE) of corn was increased by 23.2%-33.1% as compared with no-zeolite treatment; and the residual nitrogen has no significant difference between zeolite treatment and no-zeolite treatment

An electrochemical procedure coupled with a Schiff base method; application to electroorganic synthesis of new nitrogen-containing heterocycles

International Nuclear Information System (INIS)

Dowlati, Bahram; Othman, Mohamed Rozali

2013-01-01

The synthesis of Nitrogen-containing heterocycles has been achieved using chemical and electrochemical methods, respectively. The direct chemical synthesis of nucleophiles proceeds through the Schiff base chemical reaction. This procedure offers an alternate reaction between dicarbonyl compounds and diamines leads to the formation of products. The results indicate that the Schiff base chemical method for synthesis of the product has successfully performed in excellent overall yield. In the electrochemical step, a series of Nitrogen-containing compounds were electrosynthesized. Various parameters such as the applied potential, pH of the electrolytic solution, cell configuration and also purification techniques, were carried out to optimize the yields of corresponding products. New Nitrogen-containing heterocycle derivatives were synthesized using an electrochemical procedure coupled with a Schiff base as a facile, efficient and practical method. The products have been characterized after purification by IR, 1 H NMR, 13 C NMR and ESI-MS 2

Effect of different form of mineral nitrogen fertilizer and organic fertilization with compost on yield and quality of various field-grown vegetable crops (radish, carrot, spinach and tubers celery). Quality investigation through electrochemical method and the determination of p-value

International Nuclear Information System (INIS)

El-Sherbiny, M.

1998-10-01

This study was conducted to determine the effect of nitrogen form (calcium-nitrate, nitramoncal, ammonsulfate and urea) and the compost fertilization on yield and quality of different vegetable crops, which were grown under field condition at the same nitrogen fertilizer levels. In addition to evaluate the yield, the nitrate contents and p-value have been tested to determine the quality. Following results have been found: yield: the mineral nitrogen form had no significant effect on yield by radish, carrot, and celery. Spinach is positive responded by a different form of nitrogen fertilizer. The same yield results were nearly obtained by the use of compost, compared to another nitrogen fertilizer. Nitrate content: the nitrate content is investigated in edible plant parts. The nitrogen forms have been effected nitrate contents on researched vegetable crops. Generally, the minimum nitrate content is found in control variant and by use of compost, and too by ammonsulfate or urea fertilizer. The maximum nitrate content is reached by use of calcium-nitrate and nitramoncal fertilizer. Spinach leaves had less nitrate contents than stalks. P-value: results of examination shows a major relation between nitrogen fertilizer form and p-value. With the exception of carrot, had compost and control variants of radish, spinach and celery the highest significant p-value in comparison with another nitrogen fertilizer. The lowest p-value is obtained by application of calcium-nitrate and nitramoncal fertilizer, also for a better quality. (author)

Evaluation of body composition and nitrogen content of renal patients on chronic dialysis as determined by total body neutron activation

International Nuclear Information System (INIS)

Cohn, S.H.; Brennan, B.L.; Yasumura, S.; Vartsky, D.; Vaswani, A.N.; Ellis, K.J.

1983-01-01

Total body protein (nitrogen), body cell mass (potassium), fat, and water were measured in 15 renal patients on maintenance hemodialysis (MHD). Total body nitrogen was measured by means of prompt γ neutron activation analysis; total body water was determined with tritium labeled water; total body potassium was measured by whole body counting. The extracellular water was determined by a technique utilizing the measurement of total body chloride and plasma chloride. When compared with corresponding values of a control group of the same age, sex, and height, the protein content, body cell mass, and total body fat of the MHD patients were within the normal range. The only significant change was an increase in the extracellular water/body cell mass ratio in the male MHD patients compared to the control. The lack of significant difference of the nitrogen values of the MHD patients compared to matched controls suggests that dialysis minimizes any residual effects of uremic toxicity or protein-calorie malnutrition. These findings further suggest that there is a need to reevaluate the traditional anthropometric and biochemical standards of nutritional status for MHD patients. It was concluded that it is particularly important to measure protein stores of MHD patients with low protein intake to ascertain nutritional status. Finally, in vivo measurement of total body nitrogen and potassium for determination of body composition provides a simple, direct, and accurate assessment of the nutritional status of MHD patients

New method of reducing emission of nitrogen oxides at coal-dust burning thermal power plants in Japan

Energy Technology Data Exchange (ETDEWEB)

Kotler, V.R.

1987-05-01

New method of suppressing nitrogen oxide formation in the combustion process makes use of SGR- or PM-burners in the combustion chamber, augmented with auxiliary burners positioned higher in the chamber for secondary fuel with insufficient air and nozzles above the latter for tertiary air. A description of laboratory experiments on the reduction of nitrogen oxides using the above burner configuration as well as a description of the reaction process taking place during combustion are presented. Results of industrial testing of the three-stage combustion of high-nitrogen Australian black coal in a cylindrical combustion chamber developed by Hitachi-Zosen are presented.

Improved generation of single nitrogen-vacancy centers in diamond by ion implantation

Energy Technology Data Exchange (ETDEWEB)

Naydenov, Boris; Beck, Johannes; Steiner, Matthias; Balasubramanian, Gopalakrishnan; Jelezko, Fedor; Wrachtrup, Joerg [3. Institute of Physics, University of Stuttgart (Germany); Richter, Vladimir; Kalish, Rafi [Solid State Institute, Technion City, Haifa (Israel); Achard, Jocelyn [Laboratoire d' Ingenieurie des Materiaux et des Hautes Pressions, CNRS, Villetaneuse (France)

2010-07-01

Nitrogen-vacancy (NV) centers in diamond have recently attracted the attention of many research groups due to their possible application as quantum bits (qubits), ultra low magnetic field sensors and single photon sources. These color centers can be produced by nitrogen ion implantation, although the yield is usually below 5 % at low ion energies. Here we report an increase of the NV production efficiency by subsequently implanting carbon ions in the area of implanted nitrogen ions. This method improves the production yield by more than 50 %. We also show that very low nitrogen concentration (below 0.1 ppb) in diamond can be determined by converting the intrinsic nitrogen atoms to single NV centers and detecting the latter using a confocal microscope.

Validation of histamine determination Method in yoghurt using High Performance Liquid Chromatography

Directory of Open Access Journals (Sweden)

M Jahedinia

2014-02-01

Full Text Available Biogenic amines are organic, basic nitrogenous compounds of low molecular weight that are mainly generated by the enzymatic decarboxylation of amino acids by microorganisms. Dairy products are among the foods with the highest amine content. A wide variety of methods and procedures for determination of histamine and biogenic amines have been established. Amongst, HPLC method is considered as reference method. The aim of this study was to validate Reversed Phase HPLC method determination of histamine in yoghurt. The mobile phase consisted of acetonitrile/water (18:88 v/v and the flow rate was set at 0.5 ml/min using isocratic HPLC. Detection was carried out at 254 nm using UV-detector. Calibration curve that was constructed using peak area of standards was linear and value of correlation coefficient (r2 was estimated at 0.998. Good recoveries were observed for histamine under investigation at all spiking levels and average of recoveries was 84%. The RSD% value from repeatability test was found to be %4.4. Limit of detection and limit of quantitation were 0.14 and 0.42 µ/ml, respectively. The results of validation tests showed that the method is reliable and rapid for quantification of histamine in yoghurt.

Chitin: 'Forgotten' Source of Nitrogen: From Modern Chitin to Thermally Mature Kerogen: Lessons from Nitrogen Isotope Ratios

Science.gov (United States)

Schimmelmann, A.; Wintsch, R.P.; Lewan, M.D.; DeNiro, M.J.

1998-01-01

Chitinous biomass represents a major pool of organic nitrogen in living biota and is likely to have contributed some of the fossil organic nitrogen in kerogen. We review the nitrogen isotope biogeochemistry of chitin and present preliminary results suggesting interaction between kerogen and ammonium during thermal maturation. Modern arthropod chitin may shift its nitrogen isotope ratio by a few per mil depending on the chemical method of chitin preparation, mostly because N-containing non-amino-sugar components in chemically complex chitin cannot be removed quantitatively. Acid hydrolysis of chemically complex chitin and subsequent ion-chromatographic purification of the "deacetylated chitin-monomer" D-glucosamine (in hydrochloride form) provides a chemically well-defined, pure amino-sugar substrate for reproducible, high-precision determination of ??15N values in chitin. ??15N values of chitin exhibited a variability of about one per mil within an individual's exoskeleton. The nitrogen isotope ratio differed between old and new exoskeletons by up to 4 per mil. A strong dietary influence on the ??15N value of chitin is indicated by the observation of increasing ??15N values of chitin from marine crustaceans with increasing trophic level. Partial biodegradation of exoskeletons does not significantly influence ??15N values of remaining, chemically preserved amino sugar in chitin. Diagenesis and increasing thermal maturity of sedimentary organic matter, including chitin-derived nitrogen-rich moieties, result in humic compounds much different from chitin and may significantly change bulk ??15N values. Hydrous pyrolysis of immature source rocks at 330??C in contact with 15N-enriched NH4Cl, under conditions of artificial oil generation, demonstrates the abiogenic incorporation of inorganic nitrogen into carbon-bound nitrogen in kerogen. Not all organic nitrogen in natural, thermally mature kerogen is therefore necessarily derived from original organic matter, but may

Locations of oxygen, nitrogen and carbon atoms in vanadium determined by neutron diffraction

International Nuclear Information System (INIS)

Hiraga, K.; Onozuka, T.; Hirabayashi, M.

1977-01-01

The occupation sites of oxygen, nitrogen, and carbon atoms dissolved interstitially in vanadium have been determined by means of neutron diffraction with use of single crystals of VOsub(0.032), VNsub(0.013) and VCsub(0.006). It is revealed that the interstitial atoms occupy, randomly, the octahedral sites in the b.c.c. host lattice of the three crystals. Neutron diffraction is advantageous for the present purpose, since the coherent scattering amplitudes of the solute atoms are much larger than that of the vanadium atom. (Auth.)

Protein determination in single corns

International Nuclear Information System (INIS)

Knorr, J.; Schiekel, M.; Franke, W.; Focke, F.

1994-01-01

Determination of protein content in food materials is usually done by analyzing the nitrogen amount by wet chemical Kjeldahl method. An improved accuracy accompanied by smaller analyzing intervals can be achieved using nondestructive neutron activation. Analyses have been performed using 14 MeV neutrons to determine the content of N and P in single wheat corns. Irradiation parameters have been optimized to prevent serious radiation damage in grains. About 200 single corns have been investigated with total net weights ranging from 30 to 70 mg. The tested arrangement allows determination of nitrogen amount in a single corn down to 0.3 mg with an accuracy of better than 4 %. Mean nitrogen concentrations in the range from 9 to 19% per corn have been detected. (author) 5 refs.; 6 figs

A comparison between isotopic and different methods for determining urea fertilizer use efficiency under trickle figuration on tomato

International Nuclear Information System (INIS)

Mousavi Shalmani, M.A.; Sagheb, N.; Rafii, H.; Hobbi, M.S.; Khorosani, A.

2002-01-01

In order to study the fertilizer use efficiency by two different methods, an experimental design was conducted in Randomized Complete Block (RBC) with four replications and treatments in the plots with 35 square meter, area. 1200 seedlings of tomato (variety of early Urbana V.F.) were planted on June 3. 1996 at the distances of 50 cm apart. Fertilization and irrigation were performed by two fertilizer pumps (one for P and K and the other for N). The treatments of N 0 , N 1 , N 2 and N 3 received 0, 287.5, 575 and 862.5 kg N/ha respectively. The 14 N/ 15 N isotopic ratio of nitrogen gas was determined by the use of emission spectrometer and the fertilizer use efficiency was determined by using nuclear chemical equations. Because of the shortage of micro nutrients in soil and unbalanced quantity of N,P and K as fertilizers the results have shown a large amount of free radicals (NH 4 , NO 3 ) remained in the soil. This disturbed the balance between absorption of nitrogen from its different sources in the soil. Therefor, the share of fertilizer increased and in this condition, the priming effects were seen and different methods showed lower amounts of fertilizer use efficiency in comparison with the isotopic method

Development and evaluation of a gas chromatographic method for the determination of triazine herbicides in natural water samples

Science.gov (United States)

Steinheimer, T.R.; Brooks, M.G.

1984-01-01

A multi-residue method is described for the determination of triazine herbicides in natural water samples. The technique uses solvent extraction followed by gas chromatographic separation and detection employing nitrogen-selective devices. Seven compounds can be determined simultaneously at a nominal detection limit of 0.1 ??g/L in a 1-litre sample. Three different natural water samples were used for error analysis via evaluation of recovery efficiencies and estimation of overall method precision. As an alternative to liquid-liquid partition (solvent extraction) for removal of compounds of interest from water, solid-phase extraction (SPE) techniques employing chromatographic grade silicas with chemically modified surfaces have been examined. SPE is found to provide rapid and efficient concentration with quantitative recovery of some triazine herbicides from natural water samples. Concentration factors of 500 to 1000 times are obtained readily by the SPE technique.A multi-residue method is described for the determination of triazine herbicides in natural water samples. The technique uses solvent extraction followed by gas chromatographic separation and detection employing nitrogen-selective devices. Seven compounds can be determined simultaneously at a nominal detection limit of 0. 1 mu g/L in a 1-litre sample. As an alternative to liquid-liquid partition (solvent extraction) for removal of compounds of interest from water, solid-phase extraction (SPE) techniques employing chromatographic grade silicas with chemically modified surfaces have been examined. SPE is found to provide rapid and efficient concentration with quantitative recovery of some triazine herbicides from natural water samples. Concentration factors of 500 to 1000 times are obtained readily by the SPE technique.

The transport parameters of an electron swarm in nitrogen at elevated E/N

International Nuclear Information System (INIS)

Blevin, H.A.; Fletcher, J.; Reid, I.D.

1980-06-01

Values of the electron drift velocity, the longitudonal diffusion coefficient and the transverse diffusion coefficient for electron swarms in nitrogen over the range 50 Td <= E/N <500 Td have been determined by a method of counting and analysing the photons produced by such an electron swarm in a drift tube. A measure of the Nitrogen E state deactivation rate is presented

Foliage nitrogen turnover: differences among nitrogen absorbed at different times by Quercus serrata saplings

Science.gov (United States)

Ueda, Miki U.; Mizumachi, Eri; Tokuchi, Naoko

2011-01-01

Background and Aims Nitrogen turnover within plants has been intensively studied to better understand nitrogen use strategies. However, differences among the nitrogen absorbed at different times are not completely understood and the fate of nitrogen absorbed during winter is largely uncharacterized. In the present study, nitrogen absorbed at different times of the year (growing season, winter and previous growing season) was traced, and the within-leaf nitrogen turnover of a temperate deciduous oak Quercus serrata was investigated. Methods The contributions of nitrogen absorbed at the three different times to leaf construction, translocation during the growing season, and the leaf-level resorption efficiency during leaf senescence were compared using 15N. Key Results Winter- and previous growing season-absorbed nitrogen significantly contributed to leaf construction, although the contribution was smaller than that of growing season-absorbed nitrogen. On the other hand, the leaf-level resorption efficiency of winter- and previous growing season-absorbed nitrogen was higher than that of growing season-absorbed nitrogen, suggesting that older nitrogen is better retained in leaves than recently absorbed nitrogen. Conclusions The results demonstrate that nitrogen turnover in leaves varies with nitrogen absorption times. These findings are important for understanding plant nitrogen use strategies and nitrogen cycles in forest ecosystems. PMID:21515608

Nitrogen doped silicon-carbon multilayer protective coatings on carbon obtained by thermionic vacuum arc (TVA) method

Science.gov (United States)

Ciupinǎ, Victor; Vasile, Eugeniu; Porosnicu, Corneliu; Vladoiu, Rodica; Mandes, Aurelia; Dinca, Virginia; Nicolescu, Virginia; Manu, Radu; Dinca, Paul; Zaharia, Agripina

2018-02-01

To obtain protective nitrogen doped Si-C multilayer coatings on carbon, used to improve the oxidation resistance of carbon, was used TVA method. The initial carbon layer has been deposed on a silicon substrate in the absence of nitrogen, and then a 3nm Si thin film to cover carbon layer was deposed. Further, seven Si and C layers were alternatively deposed in the presence of nitrogen ions. In order to form silicon carbide at the interface between silicon and carbon layers, all carbon, silicon and nitrogen ions energy has increased up to 150eV. The characterization of microstructure and electrical properties of as-prepared N-Si-C multilayer structures were done using Transmission Electron Microscopy (TEM, STEM) techniques, Thermal Desorption Spectroscopy (TDS) and electrical measurements. The retention of oxygen in the protective layer of N-Si-C is due to the following phenomena: (a) The reaction between oxygen and silicon carbide resulting in silicon oxide and carbon dioxide; (b) The reaction involving oxygen, nitrogen and silicon resulting silicon oxinitride with a variable composition; (c) Nitrogen acts as a trapping barrier for oxygen. To perform electrical measurements, ohmic contacts were attached on the N-Si-C samples. Electrical conductivity was measured in constant current mode. To explain the temperature behavior of electrical conductivity we assumed a thermally activated electric transport mechanism.

Effects of nitrogen applocation on yield and nitrogen accumulation in soybean

International Nuclear Information System (INIS)

Di Wei; Jin Xijun; Ma Chunmei; Dong Shoukun; Gong Zhenping; Zhang Lei

2010-01-01

Methods of sand cultre and 15 N tracing were used to study the effects of nitrogen application on yield and nitrogen accumulation in soybean variety SN 14 . The results showed as follows: accumulated nitrogen in the whole plant, petiole, pod shell and seed increased at the beginning and then decreased with the increase of nitrogen levels; Nitrogen accumulation in leaf and stem increased in 3 and 5 times for N 150 than that of N 0 , which indicated that high nitrogen levels promoted the nitrogen accumulation in leaf and stem, however compared with N 0 , nitrogen accumulation in root, Nodulation-N accumulated in the whole plant and seed of N 150 decreased by 60.3%, 74. 9% and 85.7% respectively, and Fertilizer-N harvest index of N 150 decreased, which was 19.8% lower than that of N 50 , as well as Nodulation-N harvest index 25.5% lower than that of N 50 . The nitrogen levels of soybean yield also firstly increased and then decreased; Compared with N 0 , plant height, pod height and lowest pod nodes of soybean treated with N 150 increased by 55.2%, 199.7% and 142.9% respectively, while no effects were found on node number. (authors)

Determination of internal controls for quantitative gene expression of Isochrysis zhangjiangensis at nitrogen stress condition

Science.gov (United States)

Wu, Shuang; Zhou, Jiannan; Cao, Xupeng; Xue, Song

2016-02-01

Isochrysis zhangjiangensis is a potential marine microalga for biodiesel production, which accumulates lipid under nitrogen limitation conditions, but the mechanism on molecular level is veiled. Quantitative real-time polymerase chain reaction (qPCR) provides the possibility to investigate the gene expression levels, and a valid reference for data normalization is an essential prerequisite for firing up the analysis. In this study, five housekeeping genes, actin (ACT), α-tubulin (TUA), ß-tubulin (TUB), ubiquitin (UBI), 18S rRNA (18S) and one target gene, diacylglycerol acyltransferase (DGAT), were used for determining the reference. By analyzing the stabilities based on calculation of the stability index and on operating the two types of software, geNorm and bestkeeper, it showed that the reference genes widely used in higher plant and microalgae, such as UBI, TUA and 18S, were not the most stable ones in nitrogen-stressed I. zhangjiangensis, and thus are not suitable for exploring the mRNA expression levels under these experimental conditions. Our results show that ACT together with TUB is the most feasible internal control for investigating gene expression under nitrogen-stressed conditions. Our findings will contribute not only to future qPCR studies of I. zhangjiangensis, but also to verification of comparative transcriptomics studies of the microalgae under similar conditions.

A Simple and Rapid Method to Evaluate Potentially Mineralizable Nitrogen in Sewage Sludge Amended Calcareous Soils

Directory of Open Access Journals (Sweden)

Yazdan Lotfi

2005-06-01

Full Text Available Potentially mineralizable nitrogen (PMN can be usually considered as labile nitrogen. Measurement of PMN is expensive and time consuming; therefore, a simpler and more rapid alternative may facilitate routine laboratory analysis. The objective of this study was to determine the relationship between PMN and biological index of nitrogen availability (BINA. The studied soil was previously treated with 0, 25, and 100 tons ha-1 of sewage sludge with 0, 1, 2 and 3 consecutive years of application. Soil samples were taken 6 months after the latest application. PMN was measured according to Stanford and Smith procedure (20 weeks of aerobic incubation with 2 weeks leaching intervals and BINA measured as described by Bundy and Meisinger (7 days of anaerobic incubation at 40˚ C followed by extraction of NH4+. Results showed that PMN was significantly correlated with BINA (r = 0.938, P

Nitrogen concentrations in mosses indicate the spatial distribution of atmospheric nitrogen deposition in Europe

Energy Technology Data Exchange (ETDEWEB)

Harmens, H., E-mail: hh@ceh.ac.uk [Centre for Ecology and Hydrology, Environment Centre Wales, Deiniol Road, Bangor, Gwynedd LL57 2UW (United Kingdom); Norris, D.A., E-mail: danor@ceh.ac.uk [Centre for Ecology and Hydrology, Environment Centre Wales, Deiniol Road, Bangor, Gwynedd LL57 2UW (United Kingdom); Cooper, D.M., E-mail: cooper@ceh.ac.uk [Centre for Ecology and Hydrology, Environment Centre Wales, Deiniol Road, Bangor, Gwynedd LL57 2UW (United Kingdom); Mills, G., E-mail: gmi@ceh.ac.uk [Centre for Ecology and Hydrology, Environment Centre Wales, Deiniol Road, Bangor, Gwynedd LL57 2UW (United Kingdom); Steinnes, E., E-mail: Eiliv.Steinnes@chem.ntnu.no [Department of Chemistry, Norwegian University of Science and Technology, 7491 Trondheim (Norway); Kubin, E., E-mail: Eero.Kubin@metla.fi [Finnish Forest Research Institute, Kirkkosaarentie 7, 91500 Muhos (Finland); Thoeni, L., E-mail: lotti.thoeni@fub-ag.ch [FUB-Research Group for Environmental Monitoring, Alte Jonastrasse 83, 8640 Rapperswil (Switzerland); Aboal, J.R., E-mail: jesusramon.aboal@usc.es [University of Santiago de Compostela, Faculty of Biology, Department of Ecology, 15782 Santiago de Compostela (Spain); Alber, R., E-mail: Renate.Alber@provinz.bz.it [Environmental Agency of Bolzano, 39055 Laives (Italy); Carballeira, A., E-mail: alejo.carballeira@usc.es [University of Santiago de Compostela, Faculty of Biology, Department of Ecology, 15782 Santiago de Compostela (Spain); Coskun, M., E-mail: coskunafm@yahoo.com [Canakkale Onsekiz Mart University, Faculty of Medicine, Department of Medical Biology, 17100 Canakkale (Turkey); De Temmerman, L., E-mail: ludet@var.fgov.be [Veterinary and Agrochemical Research Centre, Tervuren (Belgium); Frolova, M., E-mail: marina.frolova@lvgma.gov.lv [Latvian Environment, Geology and Meteorology Agency, Riga (Latvia); Gonzalez-Miqueo, L., E-mail: lgonzale2@alumni.unav.es [Univ. of Navarra, Irunlarrea No 1, 31008 Pamplona (Spain)

2011-10-15

In 2005/6, nearly 3000 moss samples from (semi-)natural location across 16 European countries were collected for nitrogen analysis. The lowest total nitrogen concentrations in mosses (<0.8%) were observed in northern Finland and northern UK. The highest concentrations ({>=}1.6%) were found in parts of Belgium, France, Germany, Slovakia, Slovenia and Bulgaria. The asymptotic relationship between the nitrogen concentrations in mosses and EMEP modelled nitrogen deposition (averaged per 50 km x 50 km grid) across Europe showed less scatter when there were at least five moss sampling sites per grid. Factors potentially contributing to the scatter are discussed. In Switzerland, a strong (r{sup 2} = 0.91) linear relationship was found between the total nitrogen concentration in mosses and measured site-specific bulk nitrogen deposition rates. The total nitrogen concentrations in mosses complement deposition measurements, helping to identify areas in Europe at risk from high nitrogen deposition at a high spatial resolution. - Highlights: > Nitrogen concentrations in mosses were determined at ca. 3000 sites across Europe. > Moss concentrations were compared with EMEP modelled nitrogen deposition. > The asymptotic relationship for Europe showed saturation at ca. 15 kg N ha{sup -1} y{sup -1}. > Linear relationships were found with measured nitrogen deposition in some countries. > Moss concentrations complement deposition measurements at high spatial resolution. - Mosses as biomonitors of atmospheric nitrogen deposition in Europe.

Nitrogen-doped graphene: effect of graphite oxide precursors and nitrogen content on the electrochemical sensing properties.

Science.gov (United States)

Megawati, Monica; Chua, Chun Kiang; Sofer, Zdenek; Klímová, Kateřina; Pumera, Martin

2017-06-21

Graphene, produced via chemical methods, has been widely applied for electrochemical sensing due to its structural and electrochemical properties as well as its ease of production in large quantity. While nitrogen-doped graphenes are widely studied materials, the literature showing an effect of graphene oxide preparation methods on nitrogen quantity and chemical states as well as on defects and, in turn, on electrochemical sensing is non-existent. In this study, the properties of nitrogen-doped graphene materials, prepared via hydrothermal synthesis using graphite oxide produced by various classical methods using permanganate or chlorate oxidants Staudenmaier, Hummers, Hofmann and Brodie oxidation methods, were studied; the resulting nitrogen-doped graphene oxides were labeled as ST-GO, HU-GO, HO-GO and BR-GO, respectively. The electrochemical oxidation of biomolecules, such as ascorbic acid, uric acid, dopamine, nicotinamide adenine nucleotide and DNA free bases, was carried out using cyclic voltammetry and differential pulse voltammetry techniques. The nitrogen content in doped graphene oxides increased in the order ST-GO graphene followed this trend, as shown in the cyclic voltammograms. This is a very important finding that provides insight into the electrocatalytic effect of N-doped graphene. The nitrogen-doped graphene materials exhibited improved sensitivity over bare glassy carbon for ascorbic acid, uric acid and dopamine detection. These studies will enhance our understanding of the effects of graphite oxide precursors on the electrochemical sensing properties of nitrogen-doped graphene materials.

Symbiosome-like intracellular colonization of cereals and other crop plants by nitrogen-fixing bacteria for reduced inputs of synthetic nitrogen fertilizers.

Science.gov (United States)

Cocking, Edward C; Stone, Philip J; Davey, Michael R

2005-09-01

It has been forecast that the challenge of meeting increased food demand and protecting environmental quality will be won or lost in maize, rice and wheat cropping systems, and that the problem of environmental nitrogen enrichment is most likely to be solved by substituting synthetic nitrogen fertilizers by the creation of cereal crops that are able to fix nitrogen symbiotically as legumes do. In legumes, rhizobia present intracellularly in membrane-bound vesicular compartments in the cytoplasm of nodule cells fix nitrogen endosymbiotically. Within these symbiosomes, membrane-bound vesicular compartments, rhizobia are supplied with energy derived from plant photosynthates and in return supply the plant with biologically fixed nitrogen, usually as ammonia. This minimizes or eliminates the need for inputs of synthetic nitrogen fertilizers. Recently we have demonstrated, using novel inoculation conditions with very low numbers of bacteria, that cells of root meristems of maize, rice, wheat and other major non-legume crops, such as oilseed rape and tomato, can be intracellularly colonized by the non-rhizobial, non-nodulating, nitrogen fixing bacterium,Gluconacetobacter diazotrophicus that naturally occurs in sugarcane.G. diazotrophicus expressing nitrogen fixing (nifH) genes is present in symbiosome-like compartments in the cytoplasm of cells of the root meristems of the target cereals and non-legume crop species, somewhat similar to the intracellular symbiosome colonization of legume nodule cells by rhizobia. To obtain an indication of the likelihood of adequate growth and yield, of maize for example, with reduced inputs of synthetic nitrogen fertilizers, we are currently determining the extent to which nitrogen fixation, as assessed using various methods, is correlated with the extent of systemic intracellular colonization byG. diazotrophicus, with minimal or zero inputs.

Chemical characterization of 4140 steel implanted by nitrogen ions

Energy Technology Data Exchange (ETDEWEB)

Nino, Ely Dannier V.; Duran, Fernando [Grupo de Investigacion en Tecnologia del Plasma (GINTEP), Departamento de Ciencias Basicas, Universidad Pontificia Bolivariana, Bucaramanga (Colombia); Pinto, Jose L.C. [Grupo de Investigacion en Quimica Estructural (GIQUE), Universidad Industrial de Santander, Bucaramanga (Colombia); Dugar-Zhabon, V.; Garnica, Hernan [Grupo de Fisica y Tecnologia del Plasma (FITEK), Universidad Industrial de Santander, Bucaramanga (Colombia)

2010-07-01

AISI-SAE 4140 sample surfaces of different roughness which are implanted by nitrogen ions of 20 keV and 30 keV at a dose of 10{sup 17} ions/cm{sup 2} through a three dimensional ion implantation technique are studied. Crystal phases of nitrogen compositions of the implanted samples, obtained with help of an x-ray diffraction method, are confronted with the data reported by the International Centre for Diffraction Data (ICDD), PDF-2. It is observed that the implanted into the metal nitrogen atoms produce changes in orientation of crystal planes that is manifested as variations of the intensity of the refracted rays and of cell dimensions (a displacement of 2 theta of the maximum intensity position). An analysis for determining nitrogen atoms implanted by high-voltage pulsed discharges at low pressures in the crystal structure of the solid surface was carried out by X-Ray Diffraction due to this technique permits to assess the possibility of formation of new compounds. (author)

Chemical characterization of 4140 steel implanted by nitrogen ions

International Nuclear Information System (INIS)

Nino, Ely Dannier V.; Duran, Fernando; Pinto, Jose L.C.; Dugar-Zhabon, V.; Garnica, Hernan

2010-01-01

AISI-SAE 4140 sample surfaces of different roughness which are implanted by nitrogen ions of 20 keV and 30 keV at a dose of 10"1"7 ions/cm"2 through a three dimensional ion implantation technique are studied. Crystal phases of nitrogen compositions of the implanted samples, obtained with help of an x-ray diffraction method, are confronted with the data reported by the International Centre for Diffraction Data (ICDD), PDF-2. It is observed that the implanted into the metal nitrogen atoms produce changes in orientation of crystal planes that is manifested as variations of the intensity of the refracted rays and of cell dimensions (a displacement of 2 theta of the maximum intensity position). An analysis for determining nitrogen atoms implanted by high-voltage pulsed discharges at low pressures in the crystal structure of the solid surface was carried out by X-Ray Diffraction due to this technique permits to assess the possibility of formation of new compounds. (author)

Comparing Mass Balance and Adjoint-Based 4D-VAR Methods for Inverse Modeling of Nitrogen Dioxide Columns for Nitrogen Oxide Emissions

Science.gov (United States)

Cooper, M.; Martin, R.; Henze, D. K.

2016-12-01

Nitrogen oxide (NOx ≡ NO + NO2) emission inventories can be improved through top-down constraints provided by inverse modeling of observed nitrogen dioxide (NO2) columns. Here we compare two methods of inverse modeling for emissions of NOx from synthetic NO2 columns generated from known emissions using the GEOS-Chem chemical transport model and its adjoint. We treat the adjoint-based 4D-VAR approach for estimating top-down emissions as a benchmark against which to evaluate variations on the mass balance method. We find that the standard mass balance algorithm can be improved by using an iterative process and using finite difference to calculate the local sensitivity of a change in NO2 columns to a change in emissions, resulting in a factor of two reduction in inversion error. In a simplified case study to recover local emission perturbations, horizontal smearing effects due to NOx transport were better resolved by the adjoint-based approach than by mass balance. For more complex emission changes that reflect real world scenarios, the iterative finite difference mass balance and adjoint methods produce similar top-down inventories when inverting hourly synthetic observations, both reducing the a priori error by factors of 3-4. Inversions of data sets that simulate satellite observations from low Earth and geostationary orbits also indicate that both the mass balance and adjoint inversions produce similar results, reducing a priori error by a factor of 3. As the iterative finite difference mass balance method provides similar accuracy as the adjoint-based 4D-VAR method, it offers the ability to efficiently estimate top-down emissions using models that do not have an adjoint.

Difficulties in preparing a standard sample of uranium metal having traces of nitrogen

International Nuclear Information System (INIS)

Toteja, R.S.D.; Jangida, B.L.; Sundaresan, M.

1991-01-01

Normally in the analysis of uranium for nitrogen, the nitrides are hydrolysed to give NH 3 and that for standardisation purposes to approximate the closest conditions of analysis of ammonia, NH 4 Cl is added to the sample and the recovery is tested. An appropriate method will be to have a standard sample of uranium with known amounts of nitrogen to be used as reference sample. The present work describes the efforts made in the preparation of such a reference sample and a general assessment of such methods available. In present work, known microamounts of nitrogen in an enclosed volume were allowed to react at a temperature of 773 K with a fixed amount of uranium metal of nitrogen content determined chemically. As the reaction of nitrogen with uranium is essentially a surface reaction, a sample had to be homogenised by allowing the nitrided sample to melt at about 1500 K and allow the nitrogen to diffuse through so that the concentration gradient along the profile will disappear. Attempts were made to prepare such samples in the range to 40 to 100 ppm of nitrogen. The density differences of uranium nitride and uranium metal made this diffusion and homogenisation process difficult. The prepared samples were analysed by the micro-kjeldahl's method and the recoveries tested. The equipment used for the preparation of the nitrided samples, for homogenisation and analysis of the results obtained are detailed in the paper together with the assessment of the general methods. (author). 2 refs., 1 fig., 1 tab

40 CFR Appendix G to Part 75 - Determination of CO2 Emissions

Science.gov (United States)

2010-07-01

..., CO2 emissions from sorbent used in a wet flue gas desulfurization control system, fluidized bed boiler... Methods for Instrumental Determination of Carbon, Hydrogen, and Nitrogen in Petroleum Products and... Instrumental Determination of Carbon, Hydrogen, and Nitrogen in Laboratory Samples of Coal and Coke...

Experimental method to determine the role of helium in neutron-induced microstructural evolution

International Nuclear Information System (INIS)

Gelles, D.S.; Garner, F.A.

1978-12-01

A method is presented which allows the determination of the role of helium on microstructural evolution in complex alloys and which avoids many of the problems associated with other simulation experiments. It involves a direct comparison of the materials' response to a primary difference in fission and fusion environments, namely the rate of helium generation. This is accomplished by irradiating specimens in a fission reactor and conducting microstructural analyses which concentrate on alloy matrix regions adjacent to precipitates rich in boron or nitrogen. Procedures are outlined for calculation of background and injected helium levels as well as displacement doses generated by neutrons and alpha particles. An example of the analysis method is shown for an experimental austenitic stainless steel containing boride particles and irradiated to 3 and 7 x 10 22 n/cm 2

Relationship of Nitrogen Use Efficiency with the Activities of Enzymes Involved in Nitrogen Uptake and Assimilation of Finger Millet Genotypes Grown under Different Nitrogen Inputs

Directory of Open Access Journals (Sweden)

Nidhi Gupta

2012-01-01

Full Text Available Nitrogen responsiveness of three-finger millet genotypes (differing in their seed coat colour PRM-1 (brown, PRM-701 (golden, and PRM-801 (white grown under different nitrogen doses was determined by analyzing the growth, yield parameters and activities of nitrate reductase (NR, glutamine synthetase (GS, glutamate synthase; GOGAT, and glutamate dehydrogenase (GDH at different developmental stages. High nitrogen use efficiency and nitrogen utilization efficiency were observed in PRM-1 genotype, whereas high nitrogen uptake efficiency was observed in PRM-801 genotype. At grain filling nitrogen uptake efficiency in PRM-1 negatively correlated with NR, GS, GOGAT activities whereas it was positively correlated in PRM-701 and PRM-801, however, GDH showed a negative correlation. Growth and yield parameters indicated that PRM-1 responds well at high nitrogen conditions while PRM-701 and PRM-801 respond well at normal and low nitrogen conditions respectively. The study indicates that PRM-1 is high nitrogen responsive and has high nitrogen use efficiency, whereas golden PRM-701 and white PRM-801 are low nitrogen responsive genotypes and have low nitrogen use efficiency. However, the crude grain protein content was higher in PRM-801 genotype followed by PRM-701 and PRM-1, indicating negative correlation of nitrogen use efficiency with source to sink relationship in terms of seed protein content.

[Assimilation of biological nitrogen by European beaver].

Science.gov (United States)

Vecherskiĭ, M V; Naumova, E I; Kostina, N V; Umarov, M M

2009-01-01

Nitrogenase activity, the abundance of diazotrophic bacteria, the structure and functional characteristics of the complex of microorganisms, and the content of nitrogen and carbon were determined in the contents of the gastrointestinal tract of the European beaver. A high nitrogen-fixing activity in the large intestine correlated with an increase in nitrogen content in the chyme upon its transfer over the gastrointestinal tract. It is assumed that microbial nitrogen fixation plays a major role in nitrogen nutrition of the European beaver.

Glutamine nitrogen and ammonium nitrogen supplied as a nitrogen source is not converted into nitrate nitrogen of plant tissues of hydroponically grown pak-choi (Brassica chinensis L.).

Science.gov (United States)

Wang, H-J; Wu, L-H; Tao, Q-N; Miller, D D; Welch, R M

2009-03-01

Many vegetables, especially leafy vegetables, accumulate NO(-) (3)-N in their edible portions. High nitrate levels in vegetables constitute a health hazard, such as cancers and blue baby syndrome. The aim of this study was to determine if (1) ammonium nitrogen (NH(+) (4)-N) and glutamine-nitrogen (Gln-N) absorbed by plant roots is converted into nitrate-nitrogen of pak-choi (Brassica chinensis L.) tissues, and (2) if nitrate-nitrogen (NO(-) (3)-N) accumulation and concentration of pak-choi tissues linearly increase with increasing NO(-) (3)-N supply when grown in nutrient solution. In experiment 1, 4 different nitrogen treatments (no nitrogen, NH(+) (4)-N, Gln-N, and NO(-) (3)-N) with equal total N concentrations in treatments with added N were applied under sterile nutrient medium culture conditions. In experiment 2, 5 concentrations of N (from 0 to 48 mM), supplied as NO(-) (3)-N in the nutrient solution, were tested. The results showed that Gln-N and NH(+) (4)-N added to the nutrient media were not converted into nitrate-nitrogen of plant tissues. Also, NO(-) (3)-N accumulation in the pak-choi tissues was the highest when plants were supplied 24 mM NO(-) (3)-N in the media. The NO(-) (3)-N concentration in plant tissues was quadratically correlated to the NO(-) (3)-N concentration supplied in the nutrient solution.

The determination of surface of powders by BET method using nitrogen and krypton with computer calculation of the results

International Nuclear Information System (INIS)

Dembinski, W.; Zlotowski, T.

1973-01-01

A computer program written in FORTRAN language for calculations of final results of specific surface analysis based on BET theory has been described. Two gases - nitrogen and krypton were used. A technical description of measuring apparaturs is presented as well as theoretical basis of the calculations together with statistical analysis of the results for uranium compounds powders. (author)

Nuclear techniques for the determination of protein content in plant material

International Nuclear Information System (INIS)

Niemann, E.G.

1980-01-01

Elemental analysis for nitrogen has gained in importance over the last decade, as protein improvement and protein control in food and feed has come to be recognized as one of the most promising ways of overcoming deficiencies in food production and distribution. The need for fast and reliable screening methods has stimulated the improvement and automation of classic chemical methods for protein and nitrogen determination and, on the other hand, the development and adaptation of physical and nuclear analysis procedures. After about ten years of work this process has come to a stage where a critical evaluation of the existing methods seems necessary and justified. The present review describes and compares nuclear techniques for nitrogen determination in plant material. These include activation analysis techniques, based on various nuclear reactions, initiated by fast and thermal neutrons, energetic photons, protons, deuterons and α-particles. Other nuclear methods have been applied for nitrogen or protein determination, like ESCA, PIXE, NMR, NQR and Moessbauer spectroscopy, some of which possess good potential as screening methods. Depending on the needs, such as sample size, analysis rate and postulated accuracy, different nuclear techniques may be selected today for nitrogen screening. Some of the techniques discussed have additional potential for carbon or oxygen determination, for measuring depth or lateral N distribution, or for the recognition of the type of chemical N binding. Though most if not all techniques need further development for routine application, they are able to compete with chemical techniques in cost, rate and accuracy. (author)

Stannous ion determination in99mTc - radiopharmaceutical kits

International Nuclear Information System (INIS)

Almeida, M.A.T.M. de; Silva, C.P.G. da.

1989-10-01

Two simple and selective methods for determination of stannous ion in radiopharmaceutical kits are proposed. One of this permits the estimation of stannic ion. The first method used is a potentiometric tiration of Sn +2 in HCl medium using KIO 3 solution under nitrogen gas and a redox platinum electrode. The second method consist of a compleximetric tiration of tin (Sn +2 and Sn +4 ) using EDTA standart solution at pH 5.5-5.6 without use of nitrogen gas. The employed procedures indicates that both the methods can be used for routine quantitative determination of tin in most labeled radiopharmaceuticals. (author) [pt

Effect of residual nitrogen and fertilizer nitrogen on sugar beet production in Finland

Directory of Open Access Journals (Sweden)

Veikko Brummer

1974-09-01

Full Text Available Preliminary determinations for NO3- and NH4-N in topsoil from nitrogen field experiments are discussed. The amounts of residual nitrogen as well as the dates and depth for sampling are considerd in order to investigate the need of fertilizer-N for continuous sugar beet. Tops ploughed down as manure increased the available soil nitrogen by about 50 kg/ha. In practice nitrogen from fertilizer and farmyard manure given to previous beet crops seems to accumulate in the beet soils of Finland. The concentrations of nitrate and ammonium nitrogen in topsoil were low in the spring of 1972 and 1973. NO3-N increased in topsoil during the early summer, and the highest concentrations were found at the beginning of July. Starting from the middle of July the amount of NH4-N began to increase both in topsoil and in subsoil. With increasing amounts of nitrogen in the topsoil the sugar content decreases continuously. Also the α-amio N content of beets correlates with the soil nitrogen. There is experimental evidence that 150 180 kg/ha nitrate nitrogen in topsoil (residual + fertilizer N in early July gives the best economic result. The effects of fertilizer and accumulated soil nitrogen on the sugar beet quality together with som other experimental data have been statistically analysed. Regression coefficients indicated that both forms of nitrogen affected the suger content, the α-amino N concentration and clear juice purity, in a similar way.

Determination of desipramine in biological samples using liquid-liquid-liquid microextraction combined with in-syringe derivatization, gas chromatography, and nitrogen/phosphorus detection.

Science.gov (United States)

Saraji, Mohammad; Mehrafza, Narges; Bidgoli, Ali Akbar Hajialiakbari; Jafari, Mohammad Taghi

2012-10-01

A method was established for the determination of desipramine in biological samples using liquid-liquid-liquid microextraction followed by in-syringe derivatization and gas chromatography-nitrogen phosphorus detection. The extraction method was based on the use of two immiscible organic solvents. n-Dodecane was impregnated in the pores of the hollow fiber and methanol was placed inside the lumen of the fiber as the acceptor phase. Acetic anhydride was used as the reagent for the derivatization of the analyte inside the syringe barrel. Parameters that affect the extraction efficiency (composition of donor and acceptor phase, ionic strength, sample temperature, and extraction time) as well as derivatization efficiency (amount of acetic anhydride and reaction time and temperature) were investigated. The limit of detection was 0.02 μg/L with intra and interday RSDs of 2.6 and 7.7%, respectively. The linearity of the method was in the range of 0.2-20 μg/L (r(2) = 0.9986). The method was successfully applied to determine desipramine in human plasma and urine. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Assessment of external heat transfer coefficient during oocyte vitrification in liquid and slush nitrogen using numerical simulations to determine cooling rates.

Science.gov (United States)

Santos, M V; Sansinena, M; Zaritzky, N; Chirife, J

2012-01-01

In oocyte vitrification, plunging directly into liquid nitrogen favor film boiling and strong nitrogen vaporization. A survey of literature values of heat transfer coefficients (h) for film boiling of small metal objects with different geometries plunged in liquid nitrogen revealed values between 125 to 1000 W per per square m per K. These h values were used in a numerical simulation of cooling rates of two oocyte vitrification devices (open-pulled straw and Cryotop), plunged in liquid and slush nitrogen conditions. Heat conduction equation with convective boundary condition was considered a linear mathematical problem and was solved using the finite element method applying the variational formulation. COMSOL Multiphysics was used to simulate the cooling process of the systems. Predicted cooling rates for OPS and Cryotop when cooled at -196 degree C (liquid nitrogen) or -207 degree C (average for slush nitrogen) for heat transfer coefficients estimated to be representative of film boiling, indicated lowering the cooling temperature produces only a maximum 10 percent increase in cooling rates; confirming the main benefit of plunging in slush over liquid nitrogen does not arise from their temperature difference. Numerical simulations also demonstrated that a hypothetical four-fold increase in the cooling rate of vitrification devices when plunging in slush nitrogen would be explained by an increase in heat transfer coefficient. This improvement in heat transfer (i.e., high cooling rates) in slush nitrogen is attributed to less or null film boiling when a sample is placed in slush (mixture of liquid and solid nitrogen) because it first melts the solid nitrogen before causing the liquid to boil and form a film.

Pressure-volume-temperature gauging method experiment using liquid nitrogen under microgravity condition of parabolic flight

Energy Technology Data Exchange (ETDEWEB)

Seo, Man Su; Park, Hana; Yoo, Don Gyu; Jeong, Sang Kwon [Cryogenic Engineering Laboratory, Department of Mechanical Engineering, KAIST, Daejeon (Korea, Republic of); Jung, Young Suk [Launcher Systems Development Team, Korea Aerospace Research Institute, Daejeon (Korea, Republic of)

2014-06-15

Measuring an exact amount of remaining cryogenic liquid propellant under microgravity condition is one of the important issues of rocket vehicle. A Pressure-Volume-Temperature (PVT) gauging method is attractive due to its minimal additional hardware and simple gauging process. In this paper, PVT gauging method using liquid nitrogen is investigated under microgravity condition with parabolic flight. A 9.2 litre metal cryogenic liquid storage tank containing approximately 30% of liquid nitrogen is pressurized by ambient temperature helium gas. During microgravity condition, the inside of the liquid tank becomes near-isothermal condition within 1 K difference indicated by 6 silicon diode sensors vertically distributed in the middle of the liquid tank. Helium injection with higher mass flow rate after 10 seconds of the waiting time results in successful measurements of helium partial pressure in the tank. Average liquid volume measurement error is within 11% of the whole liquid tank volume and standard deviation of errors is 11.9. As a result, the applicability of PVT gauging method to liquid.

Pressure-volume-temperature gauging method experiment using liquid nitrogen under microgravity condition of parabolic flight

International Nuclear Information System (INIS)

Seo, Man Su; Park, Hana; Yoo, Don Gyu; Jeong, Sang Kwon; Jung, Young Suk

2014-01-01

Measuring an exact amount of remaining cryogenic liquid propellant under microgravity condition is one of the important issues of rocket vehicle. A Pressure-Volume-Temperature (PVT) gauging method is attractive due to its minimal additional hardware and simple gauging process. In this paper, PVT gauging method using liquid nitrogen is investigated under microgravity condition with parabolic flight. A 9.2 litre metal cryogenic liquid storage tank containing approximately 30% of liquid nitrogen is pressurized by ambient temperature helium gas. During microgravity condition, the inside of the liquid tank becomes near-isothermal condition within 1 K difference indicated by 6 silicon diode sensors vertically distributed in the middle of the liquid tank. Helium injection with higher mass flow rate after 10 seconds of the waiting time results in successful measurements of helium partial pressure in the tank. Average liquid volume measurement error is within 11% of the whole liquid tank volume and standard deviation of errors is 11.9. As a result, the applicability of PVT gauging method to liquid

Deposition of reactive nitrogen during the Rocky Mountain Airborne Nitrogen and Sulfur (RoMANS) study

International Nuclear Information System (INIS)

Beem, Katherine B.; Raja, Suresh; Schwandner, Florian M.; Taylor, Courtney; Lee, Taehyoung; Sullivan, Amy P.; Carrico, Christian M.; McMeeking, Gavin R.; Day, Derek; Levin, Ezra; Hand, Jenny; Kreidenweis, Sonia M.; Schichtel, Bret; Malm, William C.; Collett, Jeffrey L.

2010-01-01

Increases in reactive nitrogen deposition are a growing concern in the U.S. Rocky Mountain west. The Rocky Mountain Airborne Nitrogen and Sulfur (RoMANS) study was designed to improve understanding of the species and pathways that contribute to nitrogen deposition in Rocky Mountain National Park (RMNP). During two 5-week field campaigns in spring and summer of 2006, the largest contributor to reactive nitrogen deposition in RMNP was found to be wet deposition of ammonium (34% spring and summer), followed by wet deposition of nitrate (24% spring, 28% summer). The third and fourth most important reactive nitrogen deposition pathways were found to be wet deposition of organic nitrogen (17%, 12%) and dry deposition of ammonia (14%, 16%), neither of which is routinely measured by air quality/deposition networks operating in the region. Total reactive nitrogen deposition during the spring campaign was determined to be 0.45 kg ha -1 and more than doubled to 0.95 kg ha -1 during the summer campaign. - The reactive nitrogen deposition budget for Rocky Mountain National Park.

Nitrogen deposition's role in determining forest photosynthetic capacity; a FLUXNET synthesis

Science.gov (United States)

Fleischer, K.; Rebel, K.; van der Molen, M.; Erisman, J.; Wassen, M.; Dolman, H.

2011-12-01

There is growing evidence that nitrogen (N) deposition stimulates forest growth, as many forest ecosystems are N-limited. However, the significance of N deposition in determining the strength of the present and future terrestrial carbon sink is strongly debated. We investigated and quantified the effect of N deposition on ecosystem photosynthetic capacity (Amax) with the FLUXNET database, including 80 forest sites, covering the major forest types and climates of the world. The relative effect of climate and N deposition on photosynthesis was assessed with regression models. We found a significant positive correlation of Amax and N deposition for evergreen needleleaf forests in our dataset. We further found indications that foliar N and LAI scale positively with N deposition, reflecting the 2 mechanisms at which N is believed to cause an increase in carbon gain. We can support the hypothesis that foliar N is the principal scaling factor for canopy Amax across all forest types. Deciduous forests are less diverse in terms of climate and nutritional conditions for the included sites and these forests exhibited weak to no correlations with the included climate and N predictor variables. Quantifying the effect of N deposition on photosynthetic rates at the canopy level is an essential step for quantifying its contribution to the terrestrial carbon sink and for predicting vegetation response to N fertilization and global change in the future. The approach shows that eddy-covariance measurements of carbon fluxes at the canopy scale allow us to test hypotheses with respect to the expected nitrogen-photosynthesis relationships at the canopy scale.

Export of nitrogen from catchments: A worldwide analysis

International Nuclear Information System (INIS)

Alvarez-Cobelas, M.; Angeler, D.G.; Sanchez-Carrillo, S.

2008-01-01

This study reviews nitrogen export rates from 946 rivers of the world to determine the influence of quantitative (runoff, rainfall, inhabitant density, catchment area, percentage of land use cover, airborne deposition, fertilizer input) and qualitative (dominant type of forest, occurrence of stagnant waterbodies, dominant land use, occurrence of point sources, runoff type) environmental factors on nitrogen fluxes. All fractions (total, nitrate, ammonia, dissolved organic and particulate organic) of nitrogen export showed a left-skewed distribution, which suggests a relatively pristine condition for most systems. Total nitrogen export showed the highest variability whereas total organic nitrogen export comprised the dominant fraction of export. Nitrogen export rates were only weakly explained by our qualitative and quantitative environmental variables. Our study suggests that the consideration of spatial and temporal scales is important for predicting nitrogen export rates using simple and easy-to-get environmental variables. Regionally based modelling approaches prove more useful than global-scale analyses. - Spatial and temporal scales are important determinants for nitrogen export from catchments and emphasis should be put on regional approaches

Evaluation of the Impact of Alveolar Nitrogen Excretion on Indices Derived from Multiple Breath Nitrogen Washout

Science.gov (United States)

Nielsen, Niklas; Nielsen, Jorgen G.; Horsley, Alex R.

2013-01-01

Background A large body of evidence has now accumulated describing the advantages of multiple breath washout tests over conventional spirometry in cystic fibrosis (CF). Although the majority of studies have used exogenous sulphur hexafluoride (SF6) as the tracer gas this has also led to an increased interest in nitrogen washout tests, despite the differences between these methods. The impact of body nitrogen excreted across the alveoli has previously been ignored. Methods A two-compartment lung model was developed that included ventilation heterogeneity and dead space (DS) effects, but also incorporated experimental data on nitrogen excretion. The model was used to assess the impact of nitrogen excretion on washout progress and accuracy of functional residual capacity (FRC) and lung clearance index (LCI) measurements. Results Excreted nitrogen had a small effect on accuracy of FRC (1.8%) in the healthy adult model. The error in LCI calculated with true FRC was greater (6.3%), and excreted nitrogen contributed 21% of the total nitrogen concentration at the end of the washout. Increasing DS and ventilation heterogeneity both caused further increase in measurement error. LCI was increased by 6–13% in a CF child model, and excreted nitrogen increased the end of washout nitrogen concentration by 24–49%. Conclusions Excreted nitrogen appears to have complex but clinically significant effects on washout progress, particularly in the presence of abnormal gas mixing. This may explain much of the previously described differences in washout outcomes between SF6 and nitrogen. PMID:24039916

Determination method of radiostrontium

International Nuclear Information System (INIS)

1984-01-01

This manual provides determination methods of strontium-90 and strontium-89 in the environment released from nuclear facilities, and it is a revised edition of the previous manual published in 1974. As for the preparation method of radiation counting sample, ion exchange method, oxalate separation method and solvent extraction method were adopted in addition to the method of fuming nitric acid separation adopted in the previous edition. Strontium-90 is determined by the separation and radioactivity determination of yttrium-90 in radioequilibrium with strontium-90. Strontium-89 is determined by subtraction of radioactivity of strontium-90 plus yttrium-90 from gross radioactivity of isolated strontium carbonate. Radioactivity determination should be carried out with a low-background 2 π-gas-flow counting system for the mounted sample on a filter having a chemical form of ferric hydroxide, yttrium oxalate or strontium carbonate. This manual describes sample preparation procedures as well as radioactivity counting procedures for environmental samples of precipitates as rain or snow, airborne dust, fresh water, sea water and soil, and also for ash sample made from biological or food samples such as grains, vegetables, tea leaves, pine needle, milk, marine organisms, and total diet, by employing a method of fuming nitric acid separation, ion exchange separation, oxalate precipitate separation or solvent extraction separation (only for an ash sample). Procedures for reagent chemicals preparation is also attached to this manual. (Takagi, S.)

Single gas chromatography method with nitrogen phosphorus detector for urinary cotinine determination in passive and active smokers

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Lusiane Malafatti

2010-12-01

Full Text Available Nicotine is a major addictive compound in cigarettes and is rapidly and extensively metabolized to several metabolites in humans, including urinary cotinine, considered a biomarker due to its high concentration compared to other metabolites. The aim of this study was to develop a single method for determination of urinary cotinine, in active and passive smokers, by gas chromatography with a nitrogen phosphorus detector (GC-NPD. Urine (5.0 mL was extracted with 1.0 mL of sodium hydroxide 5 mol L-1, 5.0 mL of chloroform, and lidocaine used as the internal standard. Injection volume was 1 μL in GC-NPD. Limit of quantification was 10 ng mL-1. Linearity was evaluated in the ranges 10-1000 ng mL-1 and 500-6000 ng mL-1, with determination coefficients of 0.9986 and 0.9952, respectively. Intra- and inter-assay standard relative deviations were lower than 14.2 %, while inaccuracy (bias was less than +11.9%. The efficiency of extraction was greater than 88.5%. Ruggedness was verified, according to Youden's test. Means of cotinine concentrations observed were 2,980 ng mL-1 for active smokers and 132 ng mL-1, for passive smokers. The results revealed that satisfactory chromatographic separation between the analyte and interferents was obtained with a ZB-1 column. This method is reliable, precise, linear and presented ruggedness in the range evaluated. The results suggest that it can be applied in routine analysis for passive and active smokers, since it is able to quantify a wide range of cotinine concentrations in urine.A nicotina é uma substância presente no cigarro capaz de causar dependência, sendo biotransformada em vários metabólitos nos seres humanos, dentre eles a cotinina urinária, que é considerada um indicador biológico de exposição à nicotina, devido a suas altas concentrações, comparado a outras matrizes. Assim, o objetivo deste estudo foi desenvolver um único método para determinação de cotinina urinária, em amostras de

Calorimetry by immersion into liquid nitrogen and liquid argon: a better way to determine the internal surface area of micropores.

Science.gov (United States)

Navarrete, Ricardo; Llewellyn, Philip; Rouquerol, Françoise; Denoyel, Renaud; Rouquerol, Jean

2004-09-15

The aim of this work is to assess the internal surface area of a set of samples (either carbons or oxides, either porous or nonporous, either microporous or mesoporous) by microcalorimetry via immersion into liquid nitrogen or argon. We have made use of an isothermal, heat-flux microcalorimeter, initially designed and built in our laboratory for the sake of gas adsorption experiments at 77 or 87 K. It seems that immersion calorimetry into liquid nitrogen and argon makes it possible to go one step further in the determination of the internal surface area of micropores.

Measurement of nitrogen fixation in beam (Phaseolus vulgaris L.) cv. carioca, using a 15N2 low enrichment method

International Nuclear Information System (INIS)

Trivelin, P.C.O.; Matsui, E.; Saito, S.M.T.; Libardi, P.L.; Salati, E.

1984-01-01

A experimental work under field conditions to develop a method to measure atmospheric N 2 -fixation by leguminous plants, using a low enrichment 15 N 2 technique, is carried out. The experiment was developed using a N 2 -fixation measuring chamber on Terra Roxa Estruturada. The beam plants had their aereal part under normal conditions and the rooting system confined, through which a mixture of Ar, O 2 and N 2 labelled with 15 N (1.9% atom excess) was circulated from the 22nd to the 31st day from planting. Samples of the gaseous Ar, O 2 and N 2 mixture were analysed by mass spectrometry to determine 15 N concentrations and O 2 and CO 2 contents. The N 2 -fixed was measured by determination of total-N and isotopic concentration of nitrogen in the plants. (M.A.C.) [pt

Ultrafast absorption of intense x rays by nitrogen molecules

Energy Technology Data Exchange (ETDEWEB)

Buth, Christian [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany); PULSE Institute for Ultrafast Energy Science, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803 (United States); Argonne National Laboratory, Argonne, Illinois 60439 (United States); Liu Jicai [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, 69117 Heidelberg (Germany); Department of Mathematics and Physics, North China Electric Power University, 102206 Beijing (China); Chen, Mau Hsiung [Physics Division, Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Cryan, James P. [PULSE Institute for Ultrafast Energy Science, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Department of Physics, Stanford University, Stanford, California 94305 (United States); Fang Li; Hoener, Matthias; Berrah, Nora [Department of Physics, Western Michigan University, Kalamazoo, Michigan 49008 (United States); Glownia, James M. [PULSE Institute for Ultrafast Energy Science, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Department of Applied Physics, Stanford University, Stanford, California 94305 (United States); Coffee, Ryan N. [PULSE Institute for Ultrafast Energy Science, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States); Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States)

2012-06-07

We devise a theoretical description for the response of nitrogen molecules (N{sub 2}) to ultrashort and intense x rays from the free electron laser Linac Coherent Light Source (LCLS). We set out from a rate-equation description for the x-ray absorption by a nitrogen atom. The equations are formulated using all one-x-ray-photon absorption cross sections and the Auger and radiative decay widths of multiply-ionized nitrogen atoms. Cross sections are obtained with a one-electron theory and decay widths are determined from ab initio computations using the Dirac-Hartree-Slater (DHS) method. We also calculate all binding and transition energies of nitrogen atoms in all charge states with the DHS method as the difference of two self-consistent field (SCF) calculations ({Delta}SCF method). To describe the interaction with N{sub 2}, a detailed investigation of intense x-ray-induced ionization and molecular fragmentation are carried out. As a figure of merit, we calculate ion yields and the average charge state measured in recent experiments at the LCLS. We use a series of phenomenological models of increasing sophistication to unravel the mechanisms of the interaction of x rays with N{sub 2}: a single atom, a symmetric-sharing model, and a fragmentation-matrix model are developed. The role of the formation and decay of single and double core holes, the metastable states of N{sub 2}{sup 2+}, and molecular fragmentation are explained.

Nitrogen-doped carbon aerogels for electrical energy storage

Science.gov (United States)

Campbell, Patrick; Montalvo, Elizabeth; Baumann, Theodore F.; Biener, Juergen; Merrill, Matthew; Reed, Eric W.; Worsley, Marcus A.

2017-10-03

Disclosed here is a method for making a nitrogen-doped carbon aerogel, comprising: preparing a reaction mixture comprising formaldehyde, at least one nitrogen-containing resorcinol analog, at least one catalyst, and at least one solvent; curing the reaction mixture to produce a wet gel; drying the wet gel to produce a dry gel; and thermally annealing the dry gel to produce the nitrogen-doped carbon aerogel. Also disclosed is a nitrogen-doped carbon aerogel obtained according to the method and a supercapacitor comprising the nitrogen-doped carbon aerogel.

Gradual combustion - method for nitrogen oxide suppression during brown coal combustion

Energy Technology Data Exchange (ETDEWEB)

Kotler, V.P.; Verzakov, V.N.; Lobov, T.V.

1990-10-01

Discusses combustion of brown coal in BKZ-500-140-1 boilers and factors that influence emission of nitrogen oxides. Temperature distribution in the furnace was evaluated. Effects of burner position, burner number and burner type as well as air excess ratio on chemical reactions during brown coal combustion, formation of nitrogen oxides and their emission were comparatively evaluated. Analyses showed that by optimum arrangement of burners and selecting the optimum air excess ratio a part of nitrogen oxides formed during the initial phase of combustion was reduced to molecular nitrogen in the second phase. On the basis of evaluations the following recommendations for furnace design are made: use of straight-flow burners characterized by a reduced mixing ratio with secondary air, parallel arrangement of burners which guarantees mixing of the combustion products from the burners with stable and unstable combustion (products of incomplete coal combustion), reducing the air excess ratio to below 1.0. 5 refs.

Nitrogen uptake and fertilizer nitrogen use efficiency of wheat under different soil water conditions

International Nuclear Information System (INIS)

Wang Baiqun; Zhang Wei; Yu Cunzu

1999-01-01

The pot experiment was conducted to study the effects of soil water regime and fertilizer nitrogen rate on the yields, nitrogen uptake and fertilizer nitrogen utilization of wheat by using 15 N tracer method. The results showed that the aboveground biomass, stem yield and grain yield increased with the increase of soil moisture in the fertilizer nitrogen treatments. All the yield increased with the increase of the fertilizer nitrogen rate in the soil water treatments. It was found that both soil water regime and fertilizer nitrogen rate significantly influenced the amount of nitrogen uptake by wheat according to the variance analysis. The amount of nitrogen uptake increased with the rise of the soil moisture in fertilizer nitrogen treatments and the amount also increased with the increase of the urea nitrogen rate in the soil water regime. Soil water regimes not only had an impact on nitrogen uptake but also had a close relationship with soil nitrogen supply and fertilizer nitrogen use efficiency. The soil A values decreased in urea treatment and increased with the rise of the soil moisture in the combination treatment of urea with pig manure. The fertilizer nitrogen use efficiency rose with the rise of the soil moisture in the same fertilizer nitrogen treatment. The fertilizer nitrogen use efficiency of the urea treatment was 13.3%, 27.9% and 32.3% in the soils with 50%, 70% and 90% of the field water capacity, respectively. The fertilizer nitrogen use efficiency in the combination treatment of urea with pig manure was 20.0%, 29.9% and 34.4% in the soils of above three levels, respectively. It was concluded that the low soil moisture restricted urea nitrogen use efficiency (UNUE) and the UNUE could be raised by combination treatment of urea with manure in the soil of enough moisture

Nitrogen and water regime effects on corn yields determined by N-15 methodology

International Nuclear Information System (INIS)

Halitligil, M.B.; Akin, A.

2002-01-01

This investigation was carried out to determine the relationships between fertilizer N leaching and N fertilizer application time, method and irrigation rate by using 15 N methodology. Therefore, in the field experiments, the effects of three factors namely a) Irrigation rate (optimum 240 mm, high 360 mm), b) N application time (All at planting, 1/2 at planting and 1/2 after planting when plant heights were 50 cm), c) N application method (side dress and broadcast) were investigated. The field experiments were conducted using randomized block design as split-split plot and 4 replications. As the test plant hybrid corn was selected and at planting row spaces were arranged as 0.80 m x 0.25 m. Nitrogen was applied 120 kg N/ha to the all treatments as urea fertilizer (46 % N). In addition, to the sub-plots (which received half of N at planting and the other half when plant heights were 50 cm) 15 N labelled urea (2.63 % 15 N a.e. as 120 kg N/ha) was applied. After harvesting, total N and 15 N analyses were done for plant and soil samples. The results showed that the seed and total yields were increased with higher (360 mm) irrigation. When N application was side dressed the availability of N was increased, and also its loss by leaching from the active root zone was decreased. In conclusion, it was observed that at high irrigation rate was saved about 84 kg N/ha by side dressing rather than broadcasting of the applied N fertilizer

Nitrogen Research Programme STOP

International Nuclear Information System (INIS)

Erisman, J.W.; Van der Eerden, L.

2000-01-01

Nitrogen pollution is one of the main threats to the environment now in the Netherlands as well as other parts of Europe. In order to address the main gaps on the issues of nitrogen pollution related to the local scale, the Ministries of Housing, Physical Planning and Environment (VROM) and of Agriculture, Nature Management and Fisheries (LNV) have initiated a research programme, the Dutch Nitrogen Research Programme (STOP), which aims to provide a scientific basis to develop and implement policy on a local scale for the realisation and conservation of the EHS ('Dutch Mainframe of Natural Landscapes'). The results of the programme show that the description of emissions from manure in the field is difficult to describe and show large uncertainties. On the contrary, emissions from housings could be modelled well, if local actual data were available. The OPS model to describe the dispersion and deposition was evaluated with the measurements and the limitations were quantified. It appears that the model works well on the long term, whereas on the short term (hours) and short distance (tenths of meters) there is large uncertainty, especially in complex terrain. Critical loads for nitrogen for ecosystems were evaluated. Furthermore, the effect of management options was quantified. A method to determine critical loads as a function of soil conditions, such as acidification and water availability was derived. This resulted in a combination of the soil model SMART and the so-called 'nature planner' (Natuurplanner). It was concluded that the combination of SMART, the nature planner and OPS provide a good tool to develop and support policy on the local scale. 4 refs

Nitrogen-doped carbon monolith for alkaline supercapacitors and understanding nitrogen-induced redox transitions.

Science.gov (United States)

Wang, Da-Wei; Li, Feng; Yin, Li-Chang; Lu, Xu; Chen, Zhi-Gang; Gentle, Ian R; Lu, Gao Qing; Cheng, Hui-Ming

2012-04-23

A nitrogen-doped porous carbon monolith was synthesized as a pseudo-capacitive electrode for use in alkaline supercapacitors. Ammonia-assisted carbonization was used to dope the surface with nitrogen heteroatoms in a way that replaced carbon atoms but kept the oxygen content constant. Ammonia treatment expanded the micropore size-distributions and increased the specific surface area from 383 m(2) g(-1) to 679 m(2) g(-1). The nitrogen-containing porous carbon material showed a higher capacitance (246 F g(-1)) in comparison with the nitrogen-free one (186 F g(-1)). Ex situ electrochemical spectroscopy was used to investigate the evolution of the nitrogen-containing functional groups on the surface of the N-doped carbon electrodes in a three-electrode cell. In addition, first-principles calculations were explored regarding the electronic structures of different nitrogen groups to determine their relative redox potentials. We proposed possible redox reaction pathways based on the calculated redox affinity of different groups and surface analysis, which involved the reversible attachment/detachment of hydroxy groups between pyridone and pyridine. The oxidation of nitrogen atoms in pyridine was also suggested as a possible reaction pathway. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Exploring the nitrogen ingestion of aphids--a new method using electrical penetration graph and (15N labelling.

Directory of Open Access Journals (Sweden)

Franziska Kuhlmann

Full Text Available Studying plant-aphid interactions is challenging as aphid feeding is a complex process hidden in the plant tissue. Here we propose a combination of two well established methods to study nutrient acquisition by aphids focusing on the uptake of isotopically labelled nitrogen ((15N. We combined the Electrical Penetration Graph (EPG technique that allows detailed recording of aphid feeding behaviour and stable isotope ratio mass spectrometry (IRMS to precisely measure the uptake of nitrogen. Bird cherry-oat aphids Rhopalosiphum padi L. (Hemiptera, Aphididae fed for 24 h on barley plants (Hordeum vulgare L., cultivar Lina, Poaceae that were cultivated with a (15N enriched nutrient solution. The time aphids fed in the phloem was strongly positive correlated with their (15N uptake. All other single behavioural phases were not correlated with (15N enrichment in the aphids, which corroborates their classification as non-feeding EPG phases. In addition, phloem-feeding and (15N enrichment of aphids was divided into two groups. One group spent only short time in the phloem phase and was unsuccessful in nitrogen acquisition, while the other group displayed longer phloem-feeding phases and was successful in nitrogen acquisition. This suggests that several factors such as the right feeding site, time span of feeding and individual conditions play a role for the aphids to acquire nutrients successfully. The power of this combination of methods for studying plant-aphid interactions is discussed.

Effect of Different Planting Methods of Onion (Allium cepa L. and Nitrogen Rate on Onion Growth Pattern under Interference with Purple Nutsedge (Cyperus rotundus

Directory of Open Access Journals (Sweden)

N Karimi Arpnahy

2016-07-01

Full Text Available Introduction Human always has looked for improving food production through increasing crops yield. In this path, weeds through competition with crop for environmental factors and inputs have reduced the quantity and quality of crop products. Competition for nitrogen absorption not only is the most common form of intra-specific competition amongst crop plants, but also is the most popular form of inter-specific competition in the system of weed-crop interference. Therefore, understanding the method of nitrogen absorption and its allocation in competing plants, will be a key tool to improve weed management strategies. Materials and Methods In order to study the effect of sowing method and nitrogen rate on the growth pattern of onion under interference with purple nutsedge, a factorial experiment based on a randomized complete block design was conducted with three replications at the Research Greenhouse of University of Birjand in 2013. The first factor included three sowing methods of onion (seed sowing, onion set and transplanting and the second factor consisted of three levels of nitrogen (50, 100 and 150 kg N ha-1, equivalent of 25, 50 and 75 mg N kg-1 soil that urea fertilizer with a purity of 46% was used for this purpose. Results and Discussion The results of the analysis of variance showed that nitrogen levels had significant effects on plant height, leaf area index as well as aboveground and bulb dry weights. Furthermore, sowing methods revealed significant effects on plant height, leaf number, leaf area index as well as aboveground and bulb dry weights. Moreover, the interaction between sowing methods and levels of nitrogen had a significant effect on plant height, leaf area index and aboveground dry weight, while it had no significant effect on leaf number and bulb dry weight. The results of the comparisons of the means of onion planting methods and nitrogen levels interactions confirmed that the superiority of the influence of onion set

Multivariate analysis and determination of the best indirect selection criteria to genetic improvement the biological nitrogen fixation ability in common bean genotypes (Phaseolus vulgaris L.

Directory of Open Access Journals (Sweden)

Golparvar Reza Ahmad

2012-01-01

Full Text Available In order to determine the best indirect selection criteria for genetic improvement of biological nitrogen fixation, sixty four common bean genotypes were cultivated in two randomized complete block design. Genotypes were inoculated with bacteria Rhizobium legominosarum biovar Phaseoli isolate L-109 only in one of the experiments. The second experiment was considered as check for the first. Correlation analysis showed positive and highly significant correlation of majority of the traits with percent of nitrogen fixation. Step-wise regression designated that traits percent of total nitrogen of shoot, number of nodule per plant and biological yield accounted for 92.3 percent of variation exist in percent of nitrogen fixation. Path analysis indicated that these traits have direct and positive effect on percent of nitrogen fixation. Hence, these traits are promising indirect selection criteria for genetic improvement of nitrogen fixation capability in common bean genotypes especially in early generations.

Growth versus metabolic tissue replacement in mouse tissues determined by stable carbon and nitrogen isotope analysis

Science.gov (United States)

Macavoy, S. E.; Jamil, T.; Macko, S. A.; Arneson, L. S.

2003-12-01

Stable isotope analysis is becoming an extensively used tool in animal ecology. The isotopes most commonly used for analysis in terrestrial systems are those of carbon and nitrogen, due to differential carbon fractionation in C3 and C4 plants, and the approximately 3‰ enrichment in 15N per trophic level. Although isotope signatures in animal tissues presumably reflect the local food web, analysis is often complicated by differential nutrient routing and fractionation by tissues, and by the possibility that large organisms are not in isotopic equilibrium with the foods available in their immediate environment. Additionally, the rate at which organisms incorporate the isotope signature of a food through both growth and metabolic tissue replacement is largely unknown. In this study we have assessed the rate of carbon and nitrogen isotopic turnover in liver, muscle and blood in mice following a diet change. By determining growth rates, we were able to determine the proportion of tissue turnover caused by growth versus that caused by metabolic tissue replacement. Growth was found to account for approximately 10% of observed tissue turnover in sexually mature mice (Mus musculus). Blood carbon was found to have the shortest half-life (16.9 days), followed by muscle (24.7 days). Liver carbon turnover was not as well described by the exponential decay equations as other tissues. However, substantial liver carbon turnover was observed by the 28th day after diet switch. Surprisingly, these tissues primarily reflect the carbon signature of the protein, rather than carbohydrate, source in their diet. The nitrogen signature in all tissues was enriched by 3 - 5‰ over their dietary protein source, depending on tissue type, and the isotopic turnover rates were comparable to those observed in carbon.

Effects of euthanasia method on stable-carbon and stable-nitrogen isotope analysis for an ectothermic vertebrate.

Science.gov (United States)

Atwood, Meredith A

2013-04-30

Stable isotope analysis is a critical tool for understanding ecological food webs; however, results can be sensitive to sample preparation methods. To limit the possibility of sample contamination, freezing is commonly used to euthanize invertebrates and preserve non-lethal samples from vertebrates. For destructive sampling of vertebrates, more humane euthanasia methods are preferred to freezing and it is essential to evaluate how these euthanasia methods affect stable isotope results. Stable isotope ratios and elemental composition of carbon and nitrogen were used to evaluate whether the euthanasia method compromised the integrity of the sample for analysis. Specifically, the stable isotope and C:N ratios were compared for larval wood frogs (Rana sylvatica  =  Lithobates sylvaticus), an ectothermic vertebrate, that had been euthanized by freezing with four different humane euthanasia methods: CO2, benzocaine, MS-222 (tricaine methanesulfonate), and 70% ethanol. The euthanasia method was not related to the δ(13)C or δ(15)N values and the comparisons revealed no differences between freezing and any of the other treatments. However, there were slight (non-significant) differences in the isotope ratios of benzocaine and CO2 when each was compared with freezing. The elemental composition was altered by the euthanasia method employed. The percentage nitrogen was higher in CO2 treatments than in freezing, and similar (non-significant) trends were seen for ethanol treatments relative to freezing. The resulting C:N ratios were higher for benzocaine treatments than for both CO2 and ethanol. Similar (non-significant) trends suggested that the C:N ratios were also higher for animals euthanized by freezing than for both CO2 and ethanol euthanasia methods. The euthanasia method had a larger effect on elemental composition than stable isotope ratios. The percentage nitrogen and the subsequent C:N ratios were most affected by the CO2 and ethanol euthanasia methods, whereas

Nitrogen Use Efficiency and Carbon Isotope Discrimination Study on NMR151 and NMR152 Mutant Lines Rice at Field Under Different Nitrogen Rates and Water Potentials

International Nuclear Information System (INIS)

Ahmad Nazrul Abdul Wahid; Shyful Azizi Abdul Rahman; Abdul Rahim Harun; Latiffah Nordin; Abdul Razak Ruslan; Hazlina Abdullah; Khairuddin Abdul Rahim

2016-01-01

This study was conducted to evaluate the nitrogen use efficiency and "1"3C isotope discrimination of rice mutant lines viz. NMR151 and NMR152. Both cultivars are developed under rice radiation mutagenesis programme for adaptability to aerobic conditions. In the present study, NMR151 and NMR152 were grown under conditions of varying water potentials and nitrogen levels in a field. Two water potentials and three nitrogen rates in a completely randomized design with three replications were carried out. The rice mutants were grown for 110 days under two water potentials, (i) Field capacity from 0 to 110 DAS [FC], and (ii) Field capacity from 0 to 40 DAS and 30 % dry of field capacity from 41 to 110 DAS [SS] and three nitrogen rates, (i) 0 kg N/ ha (0N), (ii) 60 kg N/ ha (60N), and (iii) 120 kg N/ ha (120N). "1"5N isotopic tracer technique was used in this study, whereby the "1"5N labeled urea fertilizer 5.20 % atom excess (a.e) was utilized as a tracer for nitrogen use efficiency (NUE) study. "1"5N isotope presence in the samples was determined using emission spectrometry and percentage of total nitrogen was determined by the Kjeldahl method. "1"5N a.e values of the samples were used in the determination of the NUE. The value of "1"3C isotope discrimination (Δ"1"3C) in the sample was determined using isotope ratio mass spectrometry (IRMS). The "1"3C isotope discrimination technique was used as a tool to identify drought resistance rice cultivars with improves water use efficiency. The growth and agronomy data, viz. plant height, number of tillers, grain yield, straw yield, and 1000 grain weight also were recorded. Results from this study showed nitrogen rates imparted significant effects on yield (grain and straw) plant height, number of tillers and 1000 grain weight. Water potentials had significant effects only on 1000 grain weight and Δ"1"3C. The NUE for both mutant lines rice showed no significant different between treatments. Both Rice mutant lines rice NMR151

Calibration of Soil Available Nitrogen and Water Content with Grain Yield of Dry land Wheat

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V. Feiziasl

2017-01-01

Full Text Available Introduction: Nitrogen (N is one of the most important growth-limiting nutrients for dryland wheat. Mineral nitrogen or ammonium (NH4+ and nitrate (NO3− are two common forms of inorganic nitrogen that can serve as limiting factors for plant growth. Nitrogen fertilization in dryland area can increase the use of soil moisture, and improve wheat yields to some extent. Many researchers have been confirmed interactions between water stress and nitrogen fertilizers on wheat, especially under field conditions. Because of water stress affects forms of nitrogen uptake that leads to disorder in plant metabolism, reduction in grain yield and crop quality in dryland condition. On the other hand, use of suitable methods for determining nitrogen requirement can increase dryland wheat production. However, nitrogen recommendations should be based on soil profile content or precipitation. An efficient method for nitrogen fertilizer recommendation involves choosing an effective soil extractant and calibrating soil nitrogen (Total N, NO3− andNH4+ tests against yield responses to applied nitrogen in field experiments. Soil testing enables initial N supply to be measured and N supply throughout the season due to mineralization to be estimated. This study was carried out to establish relationship between nitrogen forms (Total N, NO3− andNH4+ in soil and soil profile water content with plant response for recommendation of nitrogen fertilizer. Materials and Methods: This study was carried out in split-split plot in a RCBD in Dryland Agricultural Research Institute (DARI, Maragheh, Iranwhere N application times (fall, 2/3 in fall and 1/3 in spring were assigned to the main plots, N rates to sub plot (0, 30, 60 and 90 kg/ha, and 7 dryland wheat genotypes to sub-sub plots (Azar2, Ohadi, Rasad and 1-4 other genotypes in three replications in 2010-2011. Soil samples were collected from 0-20, 20-40, 40-60 and 60-80 cm in sub-sub plots in shooting stage (ZGS32. Ammonium

Nitrogen nutrition of the grape-vine (Vitis vinifera spp)

International Nuclear Information System (INIS)

Conradie, W.J.

1985-12-01

A thorough knowledge concerning the nitrogen relationship in the grape-vine is essential in order to appreciate how different patterns of uptake, assimilation, storage and utilisation of nitrogen might be advantageous in particular environmental situations. The 15 N-isotope technique has been used to determine the uptake and distribution of nitrogen absorbed during early spring, early summer and autumn. Apart from the total N fraction, protein N and soluble N were determined as well. The utilisation of labelled N applied in the field, was determined for vineyards on heavier and lighter soils

Particulate carbon and nitrogen determinations in tracer studies: The neglected variables

International Nuclear Information System (INIS)

Collos, Yves; Jauzein, Cécile; Hatey, Elise

2014-01-01

We address two issues in the determination of particulate carbon and nitrogen in suspended matter of aquatic environments. One is the adsorption of dissolved organic matter on filters, leading to overestimate particulate matter. The second is the material loss during filtration due to fragile algal cells breaking up. Examples from both laboratory cultures and natural samples are presented. We recommend using stacked filters in order to estimate the first and filtering different volumes of water in order to evaluate the second. - Highlights: • Adsorption of dissolved organic matter on GF/F filters saturates below 1 ml. • Such adsorption can overestimate (up to 5 fold at low volumes) particulate matter. • Plankton breakage during filtration underestimates (up to 3 fold) particulate matter. • Different volumes should be filtered to detect biases in PC and PN concentrations. • Adsorbed organic carbon is higher in surface ocean than in mid-waters

DETERMINING THE OPTIMAL AMOUNT OF NITROGEN TO APPLY TO CORN USING THE BOX-COX FUNCTIONAL FORM

OpenAIRE

Tauer, Loren W.

2000-01-01

A Box-Cox functional form was estimated from corn-nitrogen data previously used to report optimal nitrogen use from a quadratic production function. Results suggest that less nitrogen should be app1ie.d than recommended using the quadratic function, but with more nitrogen being applied if poor growing conditions are expected.

Rapid analysis of fertilizers by the direct-reading thermometric method.

Science.gov (United States)

Sajó, I; Sipos, B

1972-05-01

The authors have developed rapid methods for the determination of the main components of fertilizers, namely phosphate, potassium and nitrogen fixed in various forms. In the absence of magnesium ions phosphate is precipitated with magnesia mixture; in the presence of magnesium ions ammonium phosphomolybdate is precipitated and the excess of molybdate is reacted with hydrogen peroxide. Potassium is determined by precipitation with silico-fluoride. For nitrogen fixed as ammonium salts the ammonium ions are condensed in a basic solution with formalin to hexamethylenetetramine; for nitrogen fixed as carbamide the latter is decomposed with sodium nitrite; for nitrogen fixed as nitrate the latter is reduced with titanium(III). In each case the temperature change of the test solution is measured. Practically all essential components of fertilizers may be determined by direct-reading thermometry; with this method and special apparatus the time of analysis is reduced to at most about 15 min for any determination.

Understanding Nitrogen Fixation

Energy Technology Data Exchange (ETDEWEB)

Paul J. Chirik

2012-05-25

The purpose of our program is to explore fundamental chemistry relevant to the discovery of energy efficient methods for the conversion of atmospheric nitrogen (N{sub 2}) into more value-added nitrogen-containing organic molecules. Such transformations are key for domestic energy security and the reduction of fossil fuel dependencies. With DOE support, we have synthesized families of zirconium and hafnium dinitrogen complexes with elongated and activated N-N bonds that exhibit rich N{sub 2} functionalization chemistry. Having elucidated new methods for N-H bond formation from dihydrogen, C-H bonds and Broensted acids, we have since turned our attention to N-C bond construction. These reactions are particularly important for the synthesis of amines, heterocycles and hydrazines with a range of applications in the fine and commodity chemicals industries and as fuels. One recent highlight was the discovery of a new N{sub 2} cleavage reaction upon addition of carbon monoxide which resulted in the synthesis of an important fertilizer, oxamide, from the diatomics with the two strongest bonds in chemistry. Nitrogen-carbon bonds form the backbone of many important organic molecules, especially those used in the fertilizer and pharamaceutical industries. During the past year, we have continued our work in the synthesis of hydrazines of various substitution patterns, many of which are important precursors for heterocycles. In most instances, the direct functionalization of N{sub 2} offers a more efficient synthetic route than traditional organic methods. In addition, we have also discovered a unique CO-induced N{sub 2} bond cleavage reaction that simultaneously cleaves the N-N bond of the metal dinitrogen compound and assembles new C-C bond and two new N-C bonds. Treatment of the CO-functionalized core with weak Broensted acids liberated oxamide, H{sub 2}NC(O)C(O)NH{sub 2}, an important slow release fertilizer that is of interest to replace urea in many applications. The

Nitrogen availability is a primary determinant of conifer mycorrhizas across complex environmental gradients

Science.gov (United States)

Filipa Cox; Nadia Barsoum; Erik A. Lilleskov; Martin I. Bidartondo

2010-01-01

Global environmental change has serious implications for functional biodiversity in temperate and boreal forests. Trees depend on mycorrhizal fungi for nutrient uptake, but predicted increases in nitrogen availability may alter fungal communities. To address a knowledge gap regarding the effects of nitrogen availability on mycorrhizal communities at large scales, we...

40 CFR Appendix B to Part 76 - Procedures and Methods for Estimating Costs of Nitrogen Oxides Controls Applied to Group 1, Boilers

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 16 2010-07-01 2010-07-01 false Procedures and Methods for Estimating Costs of Nitrogen Oxides Controls Applied to Group 1, Boilers B Appendix B to Part 76 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) ACID RAIN NITROGEN OXIDES...

Rate and time of nitrogen fertilizer application on the growth, nitrogen remobilization and yield of soyabean (Glycine max(L) Merrill)

International Nuclear Information System (INIS)

Bebeley, J. F.; Sarkodie-Addo; Duku, S.

2015-01-01

Two field experiments were conducted in 2012 at the plantation Crop section of the Department of Crop and Soil Sciences, Kwame Nkrumah University of Science and Technology, to investigate the effect N availability on nodulation, nitrogen fixation, N remobilization and grain yield of soybean. The design used in both studies was a 3 x 4 factorial arranged in randomized complete block design. Each treatment was replicated three times. The factors studied were rate and time of N fertilizer application. The N rate were 0, 20, 40 and 60kg N/ha and the time of application were early vegetative and early flowering phases. Anidaso, an improved soybean variety of 110 days maturity was used. Following land preparation, seeds were planted at the beginning of the rains at a spacing of 50 x 5cm. All required cultural practices were observed. Data collected were nodule number per plant and nodule dry weight, number of pods per plant, number of seeds per pod, 100 seeds weight, total nitrogen fixed, harvest index, grain yield and remobilized N. The total nitrogen difference method was used in determining the amount of N 2 fixed by the soybean and the micro kjeldahl method was used in determining the total plant N. The results indicated that nodulation was not significantly (p>0.05) affected by N rate and time of N application. However Nitrogen fixation was significantly (p<0.05 in affected time of N application in the minor season. Harvest index was significantly affected time of N application in the major season. Grain yield was also significantly affected by time of N application in both seasons. The results indicate that if farmers would apply N fertilizer to soybean at the vegetative growth phase, there would be increase in yield. The study also demonstrate that N remobilization occurs in soybean during grain filling although rate and time of application used did not significantly (p>0.05) affect N remobilization. (au)

Kinetics of irreversible thermal decomposition of dissociating nitrogen dioxide with nitrogen oxide or oxygen additions

International Nuclear Information System (INIS)

Gvozdev, A.A.

1987-01-01

The effect of NO or O 2 admixtures on kinetics of the irreversible thermal decomposition of nitrogen dioxide at temperatures 460-520 deg C and pressures 4-7 MPa has been studied. It follows from experimental data that the rate of N 2 O 4 formation reduces with the increase of partial pressure of oxygen or decrease of partial pressure of nitrogen oxide. The same regularity is seen for the rate of nitrogen formation. The rate constants of N 2 O formation in dissociating nitrogen tetroxide with oxygen or nitrogen oxide additions agree satisfactorily with previously published results, obtained in stoichiometric mixtures. The appreciable discrepancy at 520 deg C is bind with considerable degree of nitrogen oxide transformation which constitutes approximately 14%. It is determined that the kinetics of formation of the products of irreversible N 2 O and N 2 decomposition in stoichiometric and non-stoichiometric 2NO 2 ↔ 2NO+O 2 mixtures is described by identical 3NO → N 2 O+NO 2 and N 2 O+NO → N 2 +NO 2 reactions

Inorganic nitrogen in precipitation and atmospheric sediments

Energy Technology Data Exchange (ETDEWEB)

Matheson, D H

1951-01-01

In an investigation covering 18 months, daily determinations were made of the inorganic nitrogen contained in precipitation and atmospheric sediments collected at Hamilton, Ont. The nitrogen fall for the whole period averaged 5.8 lb. N per acre per year. Sixty-one per cent of the total nitrogen was collected on 25% of the days when precipitation occurred. The balance, occurring on days without precipitation, is attributable solely to the sedimentation of dust. Ammonia nitrogen averaged 56% of the total, but the proportion for individual days varied widely.

Exhaustive Conversion of Inorganic Nitrogen to Nitrogen Gas Based on a Photoelectro-Chlorine Cycle Reaction and a Highly Selective Nitrogen Gas Generation Cathode.

Science.gov (United States)

Zhang, Yan; Li, Jinhua; Bai, Jing; Shen, Zhaoxi; Li, Linsen; Xia, Ligang; Chen, Shuai; Zhou, Baoxue

2018-02-06

A novel method for the exhaustive conversion of inorganic nitrogen to nitrogen gas is proposed in this paper. The key properties of the system design included an exhaustive photoelectrochemical cycle reaction in the presence of Cl - , in which Cl· generated from oxidation of Cl - by photoholes selectively converted NH 4 + to nitrogen gas and some NO 3 - or NO 2 - . The NO 3 - or NO 2 - was finally reduced to nitrogen gas on a highly selective Pd-Cu-modified Ni foam (Pd-Cu/NF) cathode to achieve exhaustive conversion of inorganic nitrogen to nitrogen gas. The results indicated total nitrogen removal efficiencies of 30 mg L -1 inorganic nitrogen (NO 3 - , NH 4 + , NO 3 - /NH 4 + = 1:1 and NO 2 - /NO 3 - /NH 4 + = 1:1:1) in 90 min were 98.2%, 97.4%, 93.1%, and 98.4%, respectively, and the remaining nitrogen was completely removed by prolonging the reaction time. The rapid reduction of nitrate was ascribed to the capacitor characteristics of Pd-Cu/NF that promoted nitrate adsorption in the presence of an electric double layer, eliminating repulsion between the cathode and the anion. Nitrate was effectively removed with a rate constant of 0.050 min -1 , which was 33 times larger than that of Pt cathode. This system shows great potential for inorganic nitrogen treatment due to the high rate, low cost, and clean energy source.

Study of plasma characteristics in the cathode regime of a nitrogen glow discharge

International Nuclear Information System (INIS)

Margulis, Alvaro

1987-01-01

This research thesis reports the study of the cathode region, cathodic sheath and negative glow, of a nitrogen glow discharge. The author first presents general data regarding glow discharges, a description of the experimental installation, and measurements of discharge balancing. In the next part, he precisely describes spectroscopic methods, and the implementation of diagnoses from an experimental point of view as well as in terms of space resolution. Results are then presented and interpreted. Measurements concern space distributions of excited species, the determination of axial and radial concentrations of nitrogen ions, axial variations of rotational temperatures of the different species and variations of nitrogen ion vibrational temperature. The laser optogalvanic effect on the nitrogen molecular ion is resolved in time, and compared with the result of a theoretical model based on the mobility difference between the different nitrogen ions. Finally, the author compares experimental results on ion profiles along the discharge axis with results obtained with theoretical models [fr

The effect of different levels of fertilizer on nitrogen nutrient of pasture using 15N-isotope dilution method

International Nuclear Information System (INIS)

Wei Dongpu; Bai Lingyu; Hua Luo; Yao Yunyin

2000-01-01

A pot experiment was carried out to study the effect of different levels of fertilizer on N% of ryegrass in monoculture or mixed culture with white clover and symbiotic dinitrogen fixation of white clover by using 15 N-isotope dilution method. It showed that (1) N% of ryegrass in monoculture or mixed culture was the highest at 67 days after fertilizing (DAF) and decreased with time; (2) N% of white clover was the greatest at 67 DAF, slightly decreased at 92 DAF, and then increased at 137 DAF, related to the increasing of nitrogen fixation by white clover; (3) At 164 kg 15 NH 4 SO 4 /hm 2 , N% of ryegrass in mixed culture at different cutting time was greater than that in monoculture. It obviously occurred that fixed nitrogen was transferred from white clover to ryegrass in mixed; (4) During the whole growth period, the main nitrogen resource of white clover was symbiotic dinitrogen fixation and that of ryegrass was soil nitrogen; (5) Effect of different levels of applied N on N% of ryegrass and white clover was significant

Evaluating the Effect of Onion (Allium cepa L. Sowing Methods on Growth Characteristics of Purple Nutsedge (Cyperus rotundus L. under Different Levels of Nitrogen Fertilizer

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Nosratollah Karimi Arpnahy

2017-03-01

Full Text Available Introduction: Increasing crop competitive ability is an important part of integrated weed management (IWM. In this regard, identifying weeds reaction to soil fertility status for developing fertilizing methods, as components of IWM programs, is a necessity. Materials and Methods: In order to evaluate the growth characteristics of purple nutsedge under the conditions of interference with onion, a factorial experiment based on randomized complete block design was conducted with three replications at the Research Greenhouse of University of Birjand in 2013. The first factor included three sowing methods of onion (seed sowing, onion set and transplanting and the second factor included three levels of nitrogen (50, 100 and 150 kg N ha-1, equivalent to 25, 50 and 75 mg N kg-1 soil, urea fertilizer with a purity of 46% was used for this purpose. Results and Discussion: The results of analysis of variance showed that sowing method and nitrogen levels had significant effects on plant height, leaf area, aboveground dry weight as well as tuber number and underground dry weights. Moreover, the interaction between sowing methods and nitrogen levels had a significant effect on plant height, leaf area, aboveground dry weight as well as tuber number and underground dry weights. The results of the comparisons of the mean for the interaction of planting methods and different levels of nitrogen indicated an increased weeds growth in direct seeding method and high levels of nitrogen in weed height trait, so that the greatest nutsedge height during the growing season (92.33 cm was obtained at direct seeding method and high nitrogen levels . Moreover, the lowest weed height during the growing season was obtained at onion set planting method and 50 kg ha-1 nitrogen. The highest leaf area of purple nutsedge at ten weeks after planting (446.65 cm2, was obtained in direct seeding method and high levels of nitrogen, and the lowest value for this trait (203.38 cm2, was

Evaluation of early nodulation and Nitrogen fixation a number of Bradyrhizobium Japonicum strains to increase nitrogen fixation ability of soybean cultivars ars by using the A-value (N-15) method

International Nuclear Information System (INIS)

Piervali-Bieranvand, N.; Teimori, S.; Khorasani, A.

2004-01-01

To date significant contribution of atmospheric N fixation to soybean nutrition and growth, is approved. Nevertheless several studies have demonstrated that effectiveness of soybean -rhizobium symbiosis is medium compared with other legumes. The time course study of biological nitrogen fixation in soybean under field conditions has been shown that soybean has limited initial fixation and fixes substantially atmospheric nitrogen just during the reproductive periods (R1 until R 5).So there is the possibility of enhancing nitrogen fixation in soybean during vegetation growth. This could be done by improving inoculation methods or breeding for early nodulation. Hence, the present study was conducted to examine the effect of some Bradyrhizobium japonicum strains on early nodulation and biological nitrogen fixation three soybean cultivars by using a-value method. The experiment, was a factorial on randomized complete block design with three replications under proper glass house condition. Treatments were harvesting times(one , two and three weeks after flowering, respectively.)soybean cultivars(Chippewa, M 112 and clay )and Bradyrhizobium japonicum strains(J 1, J 3 and J 43). Ninety-plastic pots were filled with 1.5 kg of a compound of sand and soil(1:3). Rhizobial inoculation was performed by mixing 10 ml of a suspension(Yeast extract Manitol Broth) containing about 9X10 8 cells per ml to the soil of mixing pots were kept weed-free and watered with demineralized water as well as have received every two weeks 5 ml of a solution containing all the necessary nutrients except nitrogen. For measuring biological nitrogen fixation using a-value approach, two solutions of N-15 enriched ammonium sulfate containing 10.16 and %2 N-15 atom excess in amount of 5 and 25 mg N/Kg soil were mixed with soils in each pot containing fixing and reference plants, respectively. A non-nodulation isoline of soybean C v. M 129 for the all cultivars was used as a reference crop. First harvest was

Nitrogen inputs by precipitation in the Nigerian Savanna | Adeniyi ...

African Journals Online (AJOL)

Inorganic nitrogen input via direct bulk precipitation was measured, and the relation between the different nitrogen species and rainfall characteristics determined over three rainy seasons at Shagunu, a remote, sparsely populated, non-industrialized site in the northern Guinea savanna of Nigeria. Nitrogen concentration per ...

Leaf nitrogen remobilisation for plant development and grain filling.

Science.gov (United States)

Masclaux-Daubresse, C; Reisdorf-Cren, M; Orsel, M

2008-09-01

A major challenge of modern agriculture is to reduce the excessive input of fertilisers and, at the same time, to improve grain quality without affecting yield. One way to achieve this goal is to improve plant nitrogen economy through manipulating nitrogen recycling, and especially nitrogen remobilisation, from senescing plant organs. In this review, the contribution of nitrogen remobilisation efficiency (NRE) to global nitrogen use efficiency (NUE), and tools dedicated to the determination of NRE are described. An overall examination of the physiological, metabolic and genetic aspects of nitrogen remobilisation is presented.

Nitrogen Control in VIM Melts

Science.gov (United States)

Jablonski, P. D.; Hawk, J. A.

NETL has developed a design and control philosophy for the addition of nitrogen to austenitic and ferritic steels. The design approach uses CALPHAD as the centerpiece to predict the level to which nitrogen is soluble in both the melt and the solid. Applications of this technique have revealed regions of "exclusion" in which the alloy, while within specification limits of prescribed, cannot be made by conventional melt processing. Furthermore, other investigations have found that substantial retrograde solubility of nitrogen exists, which can become problematic during subsequent melt processing and/or other finishing operations such as welding. Additionally, the CALPHAD method has been used to adjust primary melt conditions. To that end, nitrogen additions have been made using chrome nitride, silicon nitride, high-nitrogen ferrochrome as well as nitrogen gas. The advantages and disadvantages of each approach will be discussed and NETL experience in this area will be summarized with respect to steel structure.

Free amino nitrogen concentration correlates to total yeast assimilable nitrogen concentration in apple juice

OpenAIRE

Boudreau, Thomas F.; Peck, Gregory M.; O'Keefe, Sean F.; Stewart, Amanda C.

2017-01-01

Abstract Yeast assimilable nitrogen (YAN) is essential for yeast growth and metabolism during apple (Malus x domestica Borkh.) cider fermentation. YAN concentration and composition can impact cider fermentation kinetics and the formation of volatile aroma compounds by yeast. The YAN concentration and composition of apples grown in Virginia, USA over the course of two seasons was determined through analysis of both free amino nitrogen (FAN) and ammonium ion concentration. FAN was the largest f...

Cyclic variations in nitrogen uptake rate of soybean plants: ammonium as a nitrogen source

Science.gov (United States)

Henry, L. T.; Raper, C. D. Jr

1989-01-01

When NO3- is the sole nitrogen source in flowing solution culture, the net rate of nitrogen uptake by nonnodulated soybean (Glycine max L. Merr. cv Ransom) plants cycles between maxima and minima with a periodicity of oscillation that corresponds with the interval of leaf emergence. Since soybean plants accumulate similar quantities of nitrogen when either NH4+ or NO3- is the sole source in solution culture controlled at pH 6.0, an experiment was conducted to determine if the oscillations in net rate of nitrogen uptake also occur when NH4+ is the nitrogen source. During a 21-day period of vegetative development, net uptake of NH4+ was measured daily by ion chromatography as depletion of NH4+ from a replenished nutrient solution containing 1.0 millimolar NH4+. The net rate of NH4+ uptake oscillated with a periodicity that was similar to the interval of leaf emergence. Instances of negative net rates of uptake indicate that the transition between maxima and minima involved changes in influx and efflux components of net NH4+ uptake.

Effect of Plant Density, Rate and Split Application of Nitrogen Fertilizer on Quality Characteristics and Nitrogen Use Efficiency of Safflower under Weed Competition

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M Fuladvand

2015-09-01

Full Text Available In order to evaluation of plant density, rate and method of nitrogen fertilizer split application on quality characteristics and nitrogen use efficiency of safflower (Sofeh variety under weed competition a field experiment was carried out in field research Yasouj University in 2013. This experiment was a factorial based on randomized complete block design with three replications. First factor was a two levels plant density (20 and 40 plants m-2 and second factor was nitrogen rate application on nine levels. That included; non nitrogen application and 75 and 150 kgN ha-1 nitrogen application that both used with four split method. Split methods were included; S1 (%50 in pre planting stage - %50 in stem elongation stage, S2 (%25 in pre planting stage - %75 in stem elongation stage, S3 (%25 in pre planting stage - %50 in stem elongation stage -%25 in flowering stage and S4 (%25 in pre planting stage - %25 in stem elongation stage - %25 in flowering stage. Also in this experiment, weed did not control. Results showed that whit increasing crop density, oil yield and protein grain yield increased by 20 percent and nitrogen utilization efficiency increased by 10 percent. The highest oil yield (50.25 g m-2 was obtained from 75 kg ha-1 nitrogen with three-stage split application (S4. Finally, results showed that increasing nitrogen fertilizer application decreased nitrogen utilization efficiency but three-stage split method application increased this trait.

Nitrogen-containing steels and thermomechanical treatment

International Nuclear Information System (INIS)

Kaputkina, L.; Prokoshkina, V.G.; Svyazhin, G.

2004-01-01

The strengthening of nitrogen-containing corrosion-resistant steels resulting from alloying and thermomechanical treatment have been investigated using X-ray diffraction analysis, light microscopy, hardness measurements and tensile testing. Combined data have been obtained for nitrogen interaction with alloying elements , peculiarities of deformed structure and short-range of nitrogen-containing steels of various structural classes. The higher nitrogen and total alloying element contents, the higher deformation strengthening. Prospects of use the steels with not high nitrogen content and methods of their thermomechanical strengthening are shown. High temperature thermomechanical treatment (HTMT) is very effective for obtaining high and thermally stable constructional strength of nitrogen-containing steels of all classes. The HTMT is most effective if used in a combination with dispersion hardening for aging steels or in the case of mechanically unstable austenitic steels. (author)

Biological nitrogen fixation in Crotalaria species estimated using the 15N isotope dilution method

International Nuclear Information System (INIS)

Samba, R.T.; Neyra, M.; Gueye, M.; Sylla, S.N.; Ndoye, I.; Dreyfus, B.

2002-01-01

Growing in Senegal by using 15 N direct isotope dilution technique. Two non-fixing plants, Senna obtusifolia and Senna occidentalis served as reference plants. The amount of nitrogen fixed two months after planting was obtained using the average of the two reference plants. The atom % 15 N excess in the Crotalaria species was significantly lower than that of the reference plants, indicating that significant nitrogen fixation occurred in the three plants. Significant differences were observed between the Crotalaria species; C. ochroleuca yielded more dry matter weight and total nitrogen than did C. perrottetti and C. retusa. The % nitrogen derived from atmosphere (%Ndfa) in leaves and stems was also higher in C. ochroleuca. There was no significant difference in %Ndfa in the whole plant between the three Crotalaria species (47% to 53%). In contrast, interspecific variability was observed based on the %Ndfa. C. ochroleuca significantly exhibited the higher amount of total nitrogen fixed, equivalent to 83 kg of nitrogen fixed per hectare. Based on these data, it was concluded that C. ochroleuca could be used in multiple cropping systems in Senegal for making more nitrogen available to other plants. (author)

Nitrogen metabolism in a grapevine in vitro system

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Nuria Llorens

2002-09-01

Full Text Available Ammonium, nitrate, nitrite, protein and individual and total amino acid contents were determined in grapevine (cv Sauvignon cultured in vitro. The enzyme activities of nitrate and nitrite reductases, glutamine synthetase, glutamate synthetase and dehydrogenase were also determined. The nitrogen taken up by the plants was 70% of the total nitrogen in the medium after 75 days of in vitro culture. Most of the nitrogen taken up was recovered in the leaves, yet only ammonia and amino acid concentrations were significantly higher in leaves. In roots, glutamine was the most abundant amino acid. In leaves, the most abundant amino acids were aspartate, glutamate, glutamine, alanine, arginine and g-aminobutirate. All enzyme activities were higher in roots than in leaves. These results suggest that both roots and leaves incorporate inorganic nitrogen into organic forms.

Immunological methods for gentamicin determination

International Nuclear Information System (INIS)

Krugers Dagneauz, P.G.L.C.; Olthuis, F.M.F.G.

1979-01-01

For immunoassay, an antibody against the substance to the determined, the pure substance itself, and a labelled form or derivative of the substance are required. The principles and problems of the preparation of antibodies are discussed, some methods for the preparation of derivatives labelled with radioactive tracers or enzymes are reviewed, and homologous enzyme-immunological determination of gentamicin is discussed in detail. A comparison is mae of three radio-immunological determination methods, and the most suitable radio-immunological method is compared with two microbiological techniques. The results are found to be comparable. (Auth.)

Effects of Controlled-Release Urea on Grain Yield of Spring Maize, Nitrogen Use Efficiency and Nitrogen Balance

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JI Jing-hong

2017-03-01

Full Text Available The effects of mixing controlled-released urea (CRU (release period of resin coated urea is 90 days and urea (U on maize yield, nitrogen use efficiency and nitrogen balance were studied by 4 plot experiments (site:Shuangcheng, Binxian, Harbin and Zhaoyuan in two years (from year 2011 to 2012 to clarify the effect of controlled release urea on spring maize and soil nitrogen balance. Results were as follow:Spring maize yield and nitrogen absorption were increased with the increasing nitrogen fertilizer. Compared with applying urea treatment, applying CRU could increase yield, nitrogen absorption, nitrogen use efficiency, agriculture efficiency of nitrogen and nitrogen contribution rate. Under the same amount of nitrogen (100%, 75%, 50%, compared with 100% U as basic fertilizer treatment, maize yield of 100% CRU treatment increased 391, 427, 291 kg·hm-2, nitrogen use efficiency increased by 5.9%,4.9% and 5.1%, agriculture efficiency of nitrogen increased 2.0, 2.6, 2.6 kg·kg-1, and nitrogen contribution rate increased 2.7%, 3.1% and 2.4%, respectively. The value of maize yield, nitrogen absorption, nitrogen use efficiency and agriculture efficiency of nitrogen between the treatment four (40% urea as basic fertilizer+60% urea as topdressing and treatment five (40% urea plus 60% controlled release urea as basic fertilizer were similar. Apparent profit and loss of nitrogen decreased with the increase of nitrogen nitrogen fertilizer. Nitrogen apparent loss by applying 100% controlled release urea was reduced of 15.0 kg·hm-2 than applying 100% U treatment;Nitrogen apparent loss amount was decreased of 23.9 kg·hm-2 under treatment five. The method of mixing 40% urea and 60% controlled release urea should be applied in maize production in Heilongjiang Province.

Isotopic composition of skeleton-bound organic nitrogen in reef-building symbiotic corals: A new method and proxy evaluation at Bermuda

Science.gov (United States)

Wang, X. T.; Sigman, D. M.; Cohen, A. L.; Sinclair, D. J.; Sherrell, R. M.; Weigand, M. A.; Erler, D. V.; Ren, H.

2015-01-01

The skeleton-bound organic nitrogen in reef-building symbiotic corals may be a high-resolution archive of ocean nitrogen cycle dynamics and a tool for understanding coral biogeochemistry and physiological processes. However, the existing methods for measuring the isotopic composition of coral skeleton-bound organic nitrogen (hereafter, CS-δ15N) either require too much skeleton material or have low precision, limiting the applications of this relatively new proxy. In addition, the controlling factors on CS-δ15N remain poorly understood: the δ15N of source nitrogen and the internal nitrogen cycle of the coral/zooxanthellae symbiosis may both be important. Here, we describe a new ("persulfate/denitrifier"-based) method for measuring CS-δ15N, requiring only 5 mg of skeleton material and yielding a long-term precision better than 0.2‰ (1σ). Using this new method, we investigate CS-δ15N at Bermuda. Ten modern Diploria labyrinthiformis coral cores/colonies from 4 sampling sites were measured for CS-δ15N. Nitrogen concentrations (nitrate + nitrite, ammonium, and dissolved organic nitrogen) and δ15N of plankton were also measured at these coral sites. Among the 4 sampling sites, CS-δ15N shows an increase with proximity to the island, from ∼3.8‰ to ∼6.8‰ vs. atmospheric N2, with the northern offshore site having a CS-δ15N 1-2‰ higher than the δ15N of thermocline nitrate in the surrounding Sargasso Sea. Two annually resolved CS-δ15N time series suggest that the offshore-inshore CS-δ15N gradient has persisted since at least the 1970s. Plankton δ15N among these 4 sites also has an inshore increase, but of only ∼1‰. Coral physiological change must explain the remaining (∼2‰) inshore increase in CS-δ15N, and previous work points to the coral/zooxanthellae N cycle as a control on host tissue (and thus carbonate skeletal) δ15N. The CS-δ15N gradient is hypothesized to result mainly from varying efficiency in the internal nitrogen recycling of the

Nitrogen balance of healthy Dutch women before and during pregnancy

NARCIS (Netherlands)

Mojtahedi, M.; Groot, de C.P.G.M.; Boekholt, H.A.; Raaij, van J.M.A.

2002-01-01

Background: Experimental studies including longitudinal nitrogen balance studies could provide insight into protein metabolism in pregnancy. Objective: Our aim was to determine the development of nitrogen balance during pregnancy compared with nitrogen balance before pregnancy in women consuming

Gas phase adsorption technology for nitrogen isotope separation and its feasibility for highly enriched nitrogen gas production

International Nuclear Information System (INIS)

Inoue, Masaki; Asaga, Takeo

2000-04-01

Highly enriched nitrogen-15 gas is favorable to reduce radioactive carbon-14 production in reactor. The cost of highly enriched nitrogen-15 gas in mass production is one of the most important subject in nitride fuel option in 'Feasibility Study for FBR and Related Fuel Cycle'. In this work gas phase adsorption technology was verified to be applicable for nitrogen isotope separation and feasible to produce highly enriched nitrogen-15 gas in commercial. Nitrogen isotopes were separated while ammonia gas flows through sodium-A type zeolite column using pressure swing adsorption process. The isotopic ratio of eight samples were measured by high resolution mass spectrometry and Fourier transform microwave spectroscopy. Gas phase adsorption technology was verified to be applicable for nitrogen isotope separation, since the isotopic ratio of nitrogen-15 and nitrogen-14 in samples were more than six times as high as in natural. The cost of highly enriched nitrogen-15 gas in mass production were estimated by the factor method. It revealed that highly enriched nitrogen-15 gas could be supplied in a few hundred yen per gram in mass production. (author)

Nitrogen isotope tracing of dissolved inorganic nitrogen behaviour in tidal estuaries

NARCIS (Netherlands)

Middelburg, J.J.; Nieuwenhuize, J.

2001-01-01

Concentration versus salinity diagrams are the most widely used method to derive estuarine sources and sinks of nitrogen. This method can not distinguish conservative mixing due to a lack of activity, from that due to an approximate balance of sources and sinks. The combined study of concentration

Determination production costs using PBC method

Directory of Open Access Journals (Sweden)

Todić Vladimir V.

2014-01-01

Full Text Available Basic characteristics of modern markets make requirements in quality increasing, decreasing prices and shortening delivery of products. In the middle of this requirements are production costs for whose determination are developed many traditional and alternative methods including PBC method (Process Based Costing. This method enables precisely locating and calculating indirect production costs, and with determined direct costs enables determination of total production costs. This paper shows usage of PBC method for determination production costs for three forms of processing cutting tools.

Production of nitrogen oxides in air pulse-periodic discharge with apokamp

Science.gov (United States)

Panarin, Victor A.; Skakun, Victor S.; Sosnin, Eduard A.; Tarasenko, Victor F.

2018-05-01

The decomposition products of pulse-periodic discharge atmospheric pressure plasma in apokamp, diffuse and corona modes were determined by optical and chemical methods. It is shown that apokamp discharge formation starts at a critical value of dissipation power in a discharge channel. Simultaneously, due to the thermochemical reactions, plasma starts to efficiently produce nitrogen oxides.

Determining water and nitrogen balances for beneficial management practices using lysimeters at Wagna test site (Austria).

Science.gov (United States)

Klammler, Gernot; Fank, Johann

2014-11-15

The shallow Murtal aquifer south of Graz, Austria, provides easily withdrawable groundwater, which is supplied as drinking water without any chemical treatment. The aquifer is also used intensively by agriculture. Common agricultural management practices are the main source for diffuse nitrogen leaching and high groundwater nitrate concentrations. To safeguard the coexisting use of these two important resources, lysimeters are operated at the agricultural test site Wagna, Austria, and the influence of two beneficial management practices--low nitrogen input and organic farming--on nitrogen leaching towards groundwater is investigated. The technical lysimeter design as presented here consists of: (1) high-resolution weighing cells, (2) a suction controlled lower boundary condition for sucking off seepage water, thus emulating undisturbed field conditions, (3) comparative soil temperature, water content and matrix potential measurements inside and outside the lysimeter at different depths, (4) an installation of the lysimeters directly into test plots and (5) a removable upper lysimeter ring enabling machinery soil tillage. Our results indicate that oasis effects or fringe effects of the lysimeter cylinder on unsaturated water flow did not occur. Another lysimeter cultivated with lawn is operated for observing grass-reference evapotranspiration, which resulted in good agreement with calculated grass-reference evapotranspiration according to the FAO-Penman-Monteith method. We conclude that lysimeters installed at Wagna test site did not show any fringe effects and, thus, are appropriate tools for measuring water balance elements and nitrogen leaching of arable and grass land at point scale. Furthermore, our results for the period of 2005 to 2011 show that beneficial management practices reduced nitrate leaching and, hence, may allow for a sustainable coexistence of drinking water supply and agriculture in the Murtal aquifer. Copyright © 2014 Elsevier B.V. All rights

Evaluation of weed control methods on sugar beet (Beta vulgaris L. yield at different levels of nitrogen

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AliAsghar Chitband

2017-03-01

Full Text Available Introduction: Weed competition is one of the major factors which limit sugar beet production in the world. Weed – crop interactions are based on competition for water, nutrients and light and allelopathic effects may also play a small role. In sugar beet weed interference, all these factors are important too, but the light is of prime importance. Due to the fact that a lot of weeds can grow above the sugar beet canopy and reduce the amount of photosynthetic radiation reaching the crop, these weeds are stronger competitors compared to smaller weeds. In much sugar beet growing areas dicot weeds of the families Chenopodiaceae, Asteraceae, Brassicaceae and Polygonaceae are of major importance. The monocots are less important compared to dicot weeds. Competition from uncontrolled annual weeds that emerge within 8 weeks of sowing or within 4 weeks of the crop reaching the two-leaf stage can reduce root yields by 26–100% .Weeds that emerge 8 weeks after sowing, and particularly after the sugar beet plants have eight or more leaves, are less likely to affect yield. Although tractor hoeing and hand labour are still used in many production areas, herbicides have been the primary method of weed control in sugar beet. The effectiveness of pre-emergence residual herbicides decreases with reductions in rainfall or soil wet content. Therefore, less than 10 % of the total sugar beet crop is treated with pre-emergence herbicides. The remaining 90 % depends solely on a selection of post-emergence herbicides to maintain season-long weed control. The major herbicides are phenmedipham, chloridazon, metamitron. Mixtures of post-emergence, broad spectrum herbicides have to be applied to control the wide range of weed species in sugar beet crops. Materials and Methods: To study the effects of weeds control by hand weeding and herbicides combination with two selective herbicides at different levels of nitrogen application on sugar beet yield and quality

Spectroscopic Investigation of Nitrogen Loaded ECR Plasmas

CERN Document Server

Ullmann, F; Zschornack, G; Küchler, D; Ovsyannikov, V P

1999-01-01

Energy dispersive X-ray spectroscopy on ions in the plasma and magnetic q/A-analysis of the extracted ions were used to determine the plasmaproperties of nitrogen loaded ECR plasmas.As the beam expands from a limited plasma region and the ion extraction process alters the plasma properties in the extraction meniscus thebeam composition does not correspond to the bulk plasma composition. The analysis of measured spectra of characteristic X-rays delivers a method to determine the ion charge state distribution and the electron energy distribution inside the plasma and does not alter the plasma anddoes not depend on the extraction and transmission properties of the ion extraction and transport system. Hence this method seems to be moreaccurate than the traditional magnetic analysis and allows to analyse different plasma regions.A comparison between ion charge state distributions determined from X-ray spectra and such from q/A-analysis shows significant differencesfor the mean ion charge states in the source plasm...

Modeling nitrogen fluxes in Germany - where does the nitrogen go?

Science.gov (United States)

Klement, Laura; Bach, Martin; Breuer, Lutz

2016-04-01

According to the latest inventory of the EU Water Framework Directive, 26.3% of German groundwater bodies are in a poor chemical state regarding nitrate. Additionally, the EU initiated infringement proceedings against Germany for not meeting the quality standards of the EU Nitrate Directive. Agriculture has been determined as the main source of nitrate pollution due to over-fertilization and regionally high density of livestock farming. The nitrogen balance surplus is commonly used as an indicator characterizing the potential of nitrate leaching into groundwater bodies and thus also serves as a foundation to introduce legislative restrictions or to monitor the success of mitigation measures. Currently, there is an ongoing discussion which measures are suitable for reducing the risk of nitrate leaching and also to what extent. However, there is still uncertainty about just how much the nitrogen surplus has to be reduced to meet the groundwater quality standards nationwide. Therefore, the aims of our study were firstly to determine the level of the nitrogen surplus that would be acceptable at the utmost and secondly whether the currently discussed target value of 30 kg N per hectare agricultural land for the soil surface nitrogen balance would be sufficient. The models MONERIS (Modeling Nutrient Emissions in River System) and MoRE (Modelling of Regionalized Emissions), the latter based on the first, are commonly used for estimating nitrogen loads into the river system in Germany at the mesoscale, as well as the effect of mitigation measures in the context of the EU directive 2008/105/EC (Environmental quality standards applicable to surface water). We used MoRE to calculate nitrate concentration for 2759 analytical units in Germany. Main factors are the surplus of the soil surface nitrogen balance, the percolation rate and an exponent representing the denitrification in the vadose zone. The modeled groundwater nitrate concentrations did not correspond to the regional

Cascading costs: an economic nitrogen cycle.

Science.gov (United States)

Moomaw, William R; Birch, Melissa B L

2005-09-01

The chemical nitrogen cycle is becoming better characterized in terms of fluxes and reservoirs on a variety of scales. Galloway has demonstrated that reactive nitrogen can cascade through multiple ecosystems causing environmental damage at each stage before being denitrified to N(2). We propose to construct a parallel economic nitrogen cascade (ENC) in which economic impacts of nitrogen fluxes can be estimated by the costs associated with each stage of the chemical cascade. Using economic data for the benefits of damage avoided and costs of mitigation in the Chesapeake Bay basin, we have constructed an economic nitrogen cascade for the region. Since a single ton of nitrogen can cascade through the system, the costs also cascade. Therefore evaluating the benefits of mitigating a ton of reactive nitrogen released needs to consider the damage avoided in all of the ecosystems through which that ton would cascade. The analysis reveals that it is most cost effective to remove a ton of nitrogen coming from combustion since it has the greatest impact on human health and creates cascading damage through the atmospheric, terrestrial, aquatic and coastal ecosystems. We will discuss the implications of this analysis for determining the most cost effective policy option for achieving environmental quality goals.

21 CFR 862.1515 - Nitrogen (amino-nitrogen) test system.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Nitrogen (amino-nitrogen) test system. 862.1515... Systems § 862.1515 Nitrogen (amino-nitrogen) test system. (a) Identification. A nitrogen (amino-nitrogen) test system is a device intended to measure amino acid nitrogen levels in serum, plasma, and urine...

Effects of Salinity and Nitrogen Application Methods on Yield and Yield Components of Wheat (Triticum aestivum L.

Directory of Open Access Journals (Sweden)

R Farshid

2012-07-01

Full Text Available To evaluate interaction of salinity stress and nitrogen use methods on yield and yield components, in experiment was conducted in split plot in randomized complete block with 3 replications. Treatments included: salinity of irrigation water levels 1.5, 4.4 and 7.9 ds/m as main plots, and nitrogen treatments 1. using N fertilizer at 3 stage in soil, 2. using two third N fertilizer in soil at planting and tillering and heading and one third in form of foliar application of N at tillering, 4. using and one third in form of foliar application at heading, 3. Using two third of N fertilizer in soil at planting one third of N fertilizer in soil at planting and two third in form of foliar application at tillering and heading, as sub plots. Results this study showed that increased in salt stress significant decreased total yield components such that showed decrease 41/5 kg/h in yield with increase in per unite salinity. Also methods of nitrogen application in salinity condition, have significant effects on total yield components. At the tillering, one stage of foliar with soil application of urea could increase spike no. m-2 and kernels of spike compared with other treatments. Foliar application of urea at heading stage increased kernels weight.

Combined method for reducing emission of sulfur dioxide and nitrogen oxides from thermal power plants

Energy Technology Data Exchange (ETDEWEB)

Kotler, V.R.; Grachev, S.P.

1991-11-01

Discusses the method developed by the Fossil Energy Research Corp. in the USA for combined desulfurization and denitrification of flue gases from coal-fired power plants. The method combines two methods tested on a commercial scale: the dry additive method for suppression of sulfur dioxide and the selective noncatalytic reduction of nitrogen oxides using urea (the NOXOUT process). The following aspects of joint flue gas desulfurization and denitrification are analyzed: flowsheets of the system, chemical reactions and reaction products, laboratory tests of the method and its efficiency, temperature effects on desulfurization and denitrification of flue gases, effects of reagent consumption rates, operating cost, efficiency of the combined method compared to other conventional methods of separate flue gas desulfurization and denitrification, economic aspects of flue gas denitrification and desulfurization. 4 refs.

Structure of inorganic phosphorus-nitrogen tetrahedral compounds

International Nuclear Information System (INIS)

Vitola, A.; Ronis, J.; Avotins, V.; Millers, T.

1997-01-01

The structure analysis of phosphorus-nitrogen compounds has shown the possibility of the P(O,N) 4 tetrahedra to form various kinds of structures. The wide spectrum of the properties determined by the diversity of structures marks the considerable promise to the future application of phosphorus-nitrogen compounds

Separation of isotopes of nitrogen and oxygen by low temperature distillation of nitrogen oxide

Energy Technology Data Exchange (ETDEWEB)

Isomura, Shohei; Tonooka, Yasuhiko; Kaetsu, Hayato

1987-02-01

In general, the distillation parameters, such as the number of theoretical plate (NTP) and the height equivalent to a theoretical plate (HETP), can be obtained from the operation at the steady state. However, it is time-consuming to achieve the steady state especially in the case of isotope separation. In this paper, with the purpose of simultaneous separation of isotopes of nitrogen and oxygen by NO distillation, we tried to determine the distillation parameters by an analytical method through the transient-state operation. It was confirmed that the results from the analysis were in good agreement with those observed for the operation at the steady state. Enrichment of the isotopes was carried out using a distillation column with a height of 1 m and inside diameter of 12 mm. The dependence of HETP on liquid flow rate was measured by the proposed method. The obtained HETP values were from 2 to 4 cm. The operation time of about 5 h was found to be long enough to determine the distillation parameters.

Separation of isotopes of nitrogen and oxygen by low temperature distillation of nitrogen oxide

International Nuclear Information System (INIS)

Isomura, Shohei; Tonooka, Yasuhiko; Kaetsu, Hayato

1987-01-01

In general, the distillation parameters, such as the number of theoretical plate (NTP) and the height equivalent to a theoretical plate (HETP), can be obtained from the operation at the steady state. However, it is time-consuming to achieve the steady state especially in the case of isotope separation. In this paper, with the purpose of simultaneous separation of isotopes of nitrogen and oxygen by NO distillation, we tried to determine the distillation parameters by an analytical method through the transient-state operation. It was confirmed that the results from the analysis were in good agreement with those observed for the operation at the steady state. Enrichment of the isotopes was carried out using a distillation column with a height of 1 m and inside diameter of 12 mm. The dependence of HETP on liquid flow rate was measured by the proposed method. The obtained HETP values were from 2 to 4 cm. The operation time of about 5 h was found to be long enough to determine the distillation parameters. (author)

Determination of critical nitrogen dilution curve based on stem dry matter in rice.

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Syed Tahir Ata-Ul-Karim

Full Text Available Plant analysis is a very promising diagnostic tool for assessment of crop nitrogen (N requirements in perspectives of cost effective and environment friendly agriculture. Diagnosing N nutritional status of rice crop through plant analysis will give insights into optimizing N requirements of future crops. The present study was aimed to develop a new methodology for determining the critical nitrogen (Nc dilution curve based on stem dry matter (SDM and to assess its suitability to estimate the level of N nutrition for rice (Oryza sativa L. in east China. Three field experiments with varied N rates (0-360 kg N ha(-1 using three Japonica rice hybrids, Lingxiangyou-18, Wuxiangjing-14 and Wuyunjing were conducted in Jiangsu province of east China. SDM and stem N concentration (SNC were determined during vegetative stage for growth analysis. A Nc dilution curve based on SDM was described by the equation (Nc = 2.17W(-0.27 with W being SDM in t ha(-1, when SDM ranged from 0.88 to 7.94 t ha(-1. However, for SDM < 0.88 t ha(-1, the constant critical value Nc = 1.76% SDM was applied. The curve was dually validated for N-limiting and non-N-limiting growth conditions. The N nutrition index (NNI and accumulated N deficit (Nand of stem ranged from 0.57 to 1.06 and 51.1 to -7.07 kg N ha(-1, respectively, during key growth stages under varied N rates in 2010 and 2011. The values of ΔN derived from either NNI or Nand could be used as references for N dressing management during rice growth. Our results demonstrated that the present curve well differentiated the conditions of limiting and non-limiting N nutrition in rice crop. The SDM based Nc dilution curve can be adopted as an alternate and novel approach for evaluating plant N status to support N fertilization decision during the vegetative growth of Japonica rice in east China.

Determining concentrations of 2-bromoallyl alcohol and dibromopropene in ground water using quantitative methods

Science.gov (United States)

Panshin, Sandra Y.

1997-01-01

A method for determining levels of 2-bromoallyl alcohol and 2,3-dibromopropene from ground-water samples using liquid/liquid extraction followed by gas chromatography/mass spectrometry is described. Analytes were extracted from the water using three aliquots of dichloromethane. The aliquots were combined and reduced in volume by rotary evaporation followed by evaporation using a nitrogen stream. The extracts were analyzed by capillary-column gas chromatography/mass spectrometry in the full-scan mode. Estimated method detection limits were 30 nanograms per liter for 2-bromoallyl alcohol and 10 nanograms per liter for 2,3-dibromopropene. Recoveries were determined by spiking three matrices at two concentration levels (0.540 and 5.40 micrograms per liter for 2-bromoallyl alcohol; and 0.534 and 5.34micro-grams per liter for dibromopropene). For seven replicates of each matrix at the high concentration level, the mean percent recoveries ranged from 43.9 to 64.9 percent for 2-bromoallyl alcohol, and from 87.5 to 99.3 percent for dibromopropene. At the low concentration level, the mean percent recoveries ranged from 43.8 to 95.2 percent for 2-bromoallyl alcohol, and from 71.3 to 84.9 percent for dibromopropene.

Method of determining local distribution of water or aqueous solutions penetrated into plastics

International Nuclear Information System (INIS)

Krejci, M.; Joks, Z.

1983-01-01

Penetrating water is labelled with tritium and the distribution is autoradiographically monitored. The discovery consists in that the plastic with the penetrating water or aqueous solution is cooled with liquid nitrogen and under the stream of liquid nitrogen the plastic is cut and exposed on the autoradiographic film in the freezer at temperatures from -15 to -30 degC. The autoradiogram will show the distribution of water in the whole area of the section. The described method may be used to detect water distribution also in filled plastics. (J.P.)

Growing media constituents determine the microbial nitrogen conversions in organic growing media for horticulture.

Science.gov (United States)

Grunert, Oliver; Reheul, Dirk; Van Labeke, Marie-Christine; Perneel, Maaike; Hernandez-Sanabria, Emma; Vlaeminck, Siegfried E; Boon, Nico

2016-05-01

Vegetables and fruits are an important part of a healthy food diet, however, the eco-sustainability of the production of these can still be significantly improved. European farmers and consumers spend an estimated €15.5 billion per year on inorganic fertilizers and the production of N-fertilizers results in a high carbon footprint. We investigated if fertilizer type and medium constituents determine microbial nitrogen conversions in organic growing media and can be used as a next step towards a more sustainable horticulture. We demonstrated that growing media constituents showed differences in urea hydrolysis, ammonia and nitrite oxidation and in carbon dioxide respiration rate. Interestingly, mixing of the growing media constituents resulted in a stimulation of the function of the microorganisms. The use of organic fertilizer resulted in an increase in amoA gene copy number by factor 100 compared to inorganic fertilizers. Our results support our hypothesis that the activity of the functional microbial community with respect to nitrogen turnover in an organic growing medium can be improved by selecting and mixing the appropriate growing media components with each other. These findings contribute to the understanding of the functional microbial community in growing media and its potential role towards a more responsible horticulture. © 2016 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

Crystalline amino acids and nitrogen emission

NARCIS (Netherlands)

Verstegen, M.W.A.; Jongbloed, A.W.

2003-01-01

Reductions in dietary protein level and supplementation with certain crystalline amino acids is a well-established method of formulating diets to achieve a more ideal amino acid pattern and to reduce nitrogen excretion. Up to 35% reduction in nitrogen excretion may be achieved by supplementing pig

Nitrogen requirements of commercial wine yeast strains during fermentation of a synthetic grape must.

Science.gov (United States)

Gutiérrez, Alicia; Chiva, Rosana; Sancho, Marta; Beltran, Gemma; Arroyo-López, Francisco Noé; Guillamon, José Manuel

2012-08-01

Nitrogen deficiencies in grape musts are one of the main causes of stuck or sluggish wine fermentations. Currently, the most common method for dealing with nitrogen-deficient fermentations is adding supplementary nitrogen (usually ammonium phosphate). However, it is important to know the specific nitrogen requirement of each strain, to avoid excessive addition that can lead to microbial instability and ethyl carbamate accumulation. In this study, we aimed to determine the effect of increasing nitrogen concentrations of three different nitrogen sources on growth and fermentation performance in four industrial wine yeast strains. This task was carried out using statistical modeling techniques. The strains PDM and RVA showed higher growth-rate and maximum population size and consumed nitrogen much more quickly than strains ARM and TTA. Likewise, the strains PDM and RVA were also the greatest nitrogen demanders. Thus, we can conclude that these differences in nitrogen demand positively correlated with higher growth rate and higher nitrogen uptake rate. The most direct effect of employing an adequate nitrogen concentration is the increase in biomass, which involves a higher fermentation rate. However, the impact of nitrogen on fermentation rate is not exclusively due to the increase in biomass because the strain TTA, which showed the worst growth behavior, had the best fermentation activity. Some strains may adapt a strategy whereby fewer cells with higher metabolic activity are produced. Regarding the nitrogen source used, all the strains showed the better and worse fermentation performance with arginine and ammonium, respectively. Copyright © 2012 Elsevier Ltd. All rights reserved.

Efficiency of Different Nitrogen Forms in Buckwheat (Fagopyrum esculentum Moench

Directory of Open Access Journals (Sweden)

Burhan Kara

2016-06-01

Full Text Available The research was carried out with aim to determination the efficient of nitrogen forms (ammonium sulfate, ammonium nitrate and urea on nitrogen use efficient for buckwheat in Isparta during 2014 and 2015 years. All the examined characteristics were determined higher values in applied nitrogen forms according to non-nitrogen parcel. In compared to nitrogen forms, the highest grain yield (1456 and 1325 kg ha-1, biological yield (4873 and 4512 kg ha-1, 1000 grain weight (24.9 and 24.8 g, agronomic efficient (24.96% and 24.25%, recycling efficient (0.24% and 0.22% and utilization efficient (0.25% and 0.18% were obtained from ammonium sulfate, the highest protein content (11.37% and 12.44% and agro-physiological efficient (0.27% and 0.24% from ammonium nitrate in both years. Among the nitrogen forms weren’t significant differently in physiological efficient in both years, recycling and utilization efficient in the first year. The mineral nutrient content varied according to nitrogen forms. Generally, ammonium sulfate was positive effect to yield and some quality parameters.

Hierarchically structured, nitrogen-doped carbon membranes

KAUST Repository

Wang, Hong

2017-08-03

The present invention is a structure, method of making and method of use for a novel macroscopic hierarchically structured, nitrogen-doped, nano-porous carbon membrane (HNDCMs) with asymmetric and hierarchical pore architecture that can be produced on a large-scale approach. The unique HNDCM holds great promise as components in separation and advanced carbon devices because they could offer unconventional fluidic transport phenomena on the nanoscale. Overall, the invention set forth herein covers a hierarchically structured, nitrogen-doped carbon membranes and methods of making and using such a membranes.

The determination of carbon, nitrogen and oxygen in TiCsub(x)Nsub(y)Osub(z) with the Auger electron spectroscopy (AES)

International Nuclear Information System (INIS)

Schneider, H.; Nold, E.; Miller, H.T.

1980-01-01

The possibility of determining the carbon, nitrogen and oxygen contents in TiCsub(x)Nsub(y)Osub(z) with the Auger-electron-spectroscopy (AES) is discussed. As an example the concentration dependence over the cross section of 1 μm thick TiN-layers is presented. (orig.)

Nitrate and Nitrogen Oxides: Sources, Health Effects and Their Remediation.

Science.gov (United States)

Hakeem, Khalid Rehman; Sabir, Muhammad; Ozturk, Munir; Akhtar, Mohd Sayeed; Ibrahim, Faridah Hanum

methods used to determine nitrogen use efficincy (NUE), determine NUE for the major cereals grown across large agroclimatic regions, determine the key factors that control NUE, and finally analyze various strategies available to improve the use efficiency of fertilizer nitrogen.

Isotopic and non-isotopic estimations of fertilizer nitrogen uptake by wheat

International Nuclear Information System (INIS)

Hamid, A.; Ahmad, M.

1990-01-01

Recoveries of fertilizer N in wheat (MexiPak-65) grown in a field experiment were calculated by difference methods including linear regression of total nitrogen in wheat plant, nitrogen 15 method and linear regression of fertilizer. The difference method overestimated recoveries of applied fertilizer at the rates of application when compared to the nitrogen 15 method. Similarly linear regression of total N in wheat on rates of N over estimated recoveries by 25% at the three rates. The difference method of calculating the recoveries of fertilizer N in wheat could give values similar to those calculated by nitrogen 15 method when the minimal N treatment was used as a base instead of zero-N. (orig./A.B.)

Soil-N tagging - a method for measurement of biological nitrogen fixation in cereal-legume intercropping system

International Nuclear Information System (INIS)

Patra, D.D.; Subbiah, B.V.; Sachdev, M.S.

1985-01-01

The quantitative estimates of atmospheric dinitrogen fixed by the legume crop and transferred to the associated cereal in cereal-legume intercropping system of maize-cowpea and wheat-gram using soil and fertilizer nitrogen labelling with 15 N have been reported. The estimates of N-fixation have been compared with the similar data from A-value method. Under field conditions sole cropped cowpea fixed 53.7 per cent of its total N uptake while as intercrop with maize fixed 43.5 per cent. Maize crop got 27.6 per cent of its total N uptake by transference of the nitrogen fixed by the intercropped cowpea. In the wheat-gram intercropping system the corresponding values under greenhouse conditions were 35.0, 44.8 and 20.2 per cent, respectively. (author)

Nitrogen in rock: Occurrences and biogeochemical implications

Science.gov (United States)

Holloway, J.M.; Dahlgren, R.A.

2002-01-01

There is a growing interest in the role of bedrock in global nitrogen cycling and potential for increased ecosystem sensitivity to human impacts in terrains with elevated background nitrogen concentrations. Nitrogen-bearing rocks are globally distributed and comprise a potentially large pool of nitrogen in nutrient cycling that is frequently neglected because of a lack of routine analytical methods for quantification. Nitrogen in rock originates as organically bound nitrogen associated with sediment, or in thermal waters representing a mixture of sedimentary, mantle, and meteoric sources of nitrogen. Rock nitrogen concentrations range from trace levels (>200 mg N kg -1) in granites to ecologically significant concentrations exceeding 1000 mg N kg -1 in some sedimentary and metasedimentary rocks. Nitrate deposits accumulated in arid and semi-arid regions are also a large potential pool. Nitrogen in rock has a potentially significant impact on localized nitrogen cycles. Elevated nitrogen concentrations in water and soil have been attributed to weathering of bedrock nitrogen. In some environments, nitrogen released from bedrock may contribute to nitrogen saturation of terrestrial ecosystems (more nitrogen available than required by biota). Nitrogen saturation results in leaching of nitrate to surface and groundwaters, and, where soils are formed from ammonium-rich bedrock, the oxidation of ammonium to nitrate may result in soil acidification, inhibiting revegetation in certain ecosystems. Collectively, studies presented in this article reveal that geologic nitrogen may be a large and reactive pool with potential for amplification of human impacts on nitrogen cycling in terrestrial and aquatic ecosystems.

Simultaneous cardiac output and regional myocardial perfusion determination with PET and nitrogen 13 ammonia

DEFF Research Database (Denmark)

Hove, Jens D; Kofoed, Klaus F; Wu, Hsiao M

2003-01-01

The purpose of this study was to evaluate the possibility of measuring cardiac output during positron emission tomography (PET) examination of myocardial perfusion with nitrogen 13 ammonia.......The purpose of this study was to evaluate the possibility of measuring cardiac output during positron emission tomography (PET) examination of myocardial perfusion with nitrogen 13 ammonia....

Staged combustion - main method for suppressing nitrogen oxides in pulverized-coal fired boilers

Energy Technology Data Exchange (ETDEWEB)

Kotler, V.R. (Vsesoyuznyi Teplotekhnicheskii Institut (USSR))

1989-08-01

Describes principles behind staged combustion, which is based on organizing furnace operations so that only part of the air from the fuel is taken into the furnace. The remaining air, which is needed for combustion, is fed as a tertiary blast jet into the intermediate flame zone. Following inflammation and combustion of the volatile matter, the oxygen concentration in the flame drops sharply causing a retardation of the oxidation reactions forming NO and an intensification of the reactions causing the nitrogen-containing radicals NH{sub i} and CN to be converted into N{sub 2}. When the reducing agents CO, H{sub 2} and CH{sub 4} are present in certain flame zones, even the nitrogen oxide is reduced to N{sub 2}. The NO concentrations in the flame are reduced until the jet of tertiary air is introduced. Discusses with reference to practice in the USA and Western Europe how to achieve maximum effect of this method for different types of boiler and presents the results of observations of the introduction of staged combustion to the BKZ-210-140 boiler burning Kuznetsk gassy coal. 5 refs.

Nitrogen concentration profiles in oxy-nitrited high-speed steel

International Nuclear Information System (INIS)

Barcz, A.; Turos, A.; Wielunski, L.

1976-01-01

Nuclear microanalysis has been applied for the determination of in-depth concentration profiles of nitrogen in oxy-nitrided high-speed steel. The concentration profiles were deduced from measurements of the nitrogen content, determined by means of the 14 N(d,α) 12 C reaction for the set of initially identical samples after the removal of surface layers of sequentially increasing thicknesses. The 1.2 MeV deuterons were obtained from the Institute of Nuclear Research Van de Graaf accelerator LECH. The α-particles produced in the 14 N(d,α) 12 C reaction were detected by means of silicon surface barrier detector mounted at 150 deg C. Strong blocking of the nitrogen diffusion due to the presence of oxygen has been observed. The accuracy of nitrogen detection is of the order of 5% for nitrogen-rich regions and 10% for the matrix. However, the local non-uniformity of the steel may cause a spread of about 20% of the measured values. (T.G.)

Method of molybdenum kinetic determination

International Nuclear Information System (INIS)

Krejngol'd, S.U.; Dzotsenidze, N.E.; Ruseishviyai, T.G.; Nelen', I.M.

1980-01-01

The method molybdenum kinetic determination according to oxidation of pyrogallol with bromate in the medium of 0.05-0.15 M perchloric or sulphuric acids is presented. 1 mg of Ni, Co, Mn, Mg, Zn, Cr(3); 100 μg of Ca, Al, Cu, 10 μg of Cr(4), W; 10 μg of Fe in the presence of 22x10 - 4 M solution of EDTA, as well as 10 - 4 M solutions of chlorides and fluorides, 10 - 5 M solutions of bromides do not interfere with molybdenum determination using the given method. The method is rather simple, it takes 30 min to carry out the analysis. Determination limit of molybdenum constitutes 0.01 μg/ml

Determination of N-containing halogenated natural products using gas chromatography in combination of a nitrogen-phosphorus-detector

Energy Technology Data Exchange (ETDEWEB)

Melcher, J.; Vetter, W. [Hohenheim Univ., Stuttgart (Germany). Inst. fuer Lebensmittelchemie

2004-09-15

In the last few years several nonpolar halogenated natural products (HNPs) such as Q1, MHC-1, BC-2, BC-3, BC-10 were detected at elevated concentrations in marine biota samples. In addition, there are still some abundant peaks of halogenated compounds frequently found in the gas chromatograms of many marine samples which have not yet been identified. Some of the known halogenated natural products (Q1, HDBPs including BC-10, bromoindoles) contain N-heterocyclic backbones. Since nitrogen is scarcely found in anthropogenic halogenated compounds, the detection of N-containing halogenated substances may be used as a first indicator for the presence of HNPs in a sample extract. In the presented method we studied the suitability of a nitrogen phosphorous detector (NPD) for quantification of Q1 and the detection of Ncontaining compounds in marine biota. Analyses were accompanied with GC/ECD analyses.

Nitrate signals determine the sensing of nitrogen through differential expression of genes involved in nitrogen uptake and assimilation in finger millet.

Science.gov (United States)

Gupta, Alok Kumar; Gaur, Vikram Singh; Gupta, Sanjay; Kumar, Anil

2013-06-01

In order to understand the molecular basis of high nitrogen use efficiency of finger millet, five genes (EcHNRT2, EcLNRT1, EcNADH-NR, EcGS, and EcFd-GOGAT) involved in nitrate uptake and assimilation were isolated using conserved primer approaches. Expression profiles of these five genes along with the previously isolated EcDof1 was studied under increased KNO3 concentrations (0.15 to 1,500 μM) for 2 h as well as at 1.5 μM for 24 h in the roots and shoots of 25 days old nitrogen deprived two contrasting finger millet genotypes (GE-3885 and GE-1437) differing in grain protein content (13.76 and 6.15 %, respectively). Time kinetics experiment revealed that, all the five genes except EcHNRT2 in the leaves of GE-3885 were induced within 30 min of nitrate exposure indicating that there might be a greater nitrogen deficit in leaves and therefore quick transportation of nitrate signals to the leaves. Exposing the plants to increasing nitrate concentrations for 2 h showed that in roots of GE-3885, NR was strongly induced while GS was repressed; however, the pattern was found to be reversed in leaves of GE-1437 indicating that in GE-3885, most of the nitrate might be reduced in the roots but assimilated in leaves and vice-versa. Furthermore, compared with the low-protein genotype, expression of HNRT2 was strongly induced in both roots and shoots of high-protein genotype at the least nitrate concentration supplied. This further indicates that GE-3885 is a quick sensor of nitrogen compared with the low-protein genotype. Furthermore, expression of EcDof1 was also found to overlap the expression of NR, GS, and GOGAT indicating that Dof1 probably regulates the expression of these genes under different conditions by sensing the nitrogen fluctuations around the root zone.

Fluxes of oxidised and reduced nitrogen above a mixed coniferous forest exposed to various nitrogen emission sources

International Nuclear Information System (INIS)

Neirynck, J.; Kowalski, A.S.; Carrara, A.; Genouw, G.; Berghmans, P.; Ceulemans, R.

2007-01-01

Concentrations of nitrogen gases (NH 3 , NO 2 , NO, HONO and HNO 3 ) and particles (pNH 4 and pNO 3 ) were measured over a mixed coniferous forest impacted by high nitrogen loads. Nitrogen dioxide (NO 2 ) represented the main nitrogen form, followed by nitric oxide (NO) and ammonia (NH 3 ). A combination of gradient method (NH 3 and NO x ) and resistance modelling techniques (HNO 3 , HONO, pNH 4 and pNO 3 ) was used to calculate dry deposition of nitrogen compounds. Net flux of NH 3 amounted to -64 ng N m -2 s -1 over the measuring period. Net fluxes of NO x were upward (8.5 ng N m -2 s -1 ) with highest emission in the morning. Fluxes of other gases or aerosols substantially contributed to dry deposition. Total nitrogen deposition was estimated at -48 kg N ha -1 yr -1 and consisted for almost 80% of NH x . Comparison of throughfall nitrogen with total deposition suggested substantial uptake of reduced N (±15 kg N ha -1 yr -1 ) within the canopy. - Reduced nitrogen was found to be the main contributor to total deposition which was predominantly governed by dry deposition

Nitrogen and triple oxygen isotopes in near-road air samples using chemical conversion and thermal decomposition.

Science.gov (United States)

Smirnoff, Anna; Savard, Martine M; Vet, Robert; Simard, Marie-Christine

2012-12-15

The determination of triple oxygen (δ(18)O and δ(17)O) and nitrogen isotopes (δ(15)N) is important when investigating the sources and atmospheric paths of nitrate and nitrite. To fully understand the atmospheric contribution into the terrestrial nitrogen cycle, it is crucial to determine the δ(15)N values of oxidised and reduced nitrogen species in precipitation and dry deposition. In an attempt to further develop non-biotic methods and avoid expensive modifications of the gas-equilibration system, we have combined and modified sample preparation procedures and analytical setups used by other researchers. We first chemically converted NO(3)(-) and NH(4)(+) into NO(2)(-) and then into N(2)O. Subsequently, the resulting gas was decomposed into N(2) and O(2) and analyzed by isotope ratio mass spectrometry (IRMS) using a pre-concentration system equipped with a gold reduction furnace. The δ(17)O, δ(18)O and δ(15)N values of nitrate and nitrite samples were acquired simultaneously in one run using a single analytical system. Most importantly, the entire spectrum of δ(17)O, δ(18)O and/or δ(15)N values was determined from atmospheric nitrate, nitric oxide, ammonia and ammonium. The obtained isotopic values for air and precipitation samples were in good agreement with those from previous studies. We have further advanced chemical approaches to sample preparation and isotope analyses of nitrogen-bearing compounds. The proposed methods are inexpensive and easily adaptable to a wide range of laboratory conditions. This will substantially contribute to further studies on sources and pathways of nitrate, nitrite and ammonium in terrestrial nitrogen cycling. Copyright © 2012 Crown in the right of Canada. Published by John Wiley & Sons, Ltd.

Phosphorus determination by various substoichiometric methods

International Nuclear Information System (INIS)

Shigematsu, Toshio; Kudo, Kiyoshi

1981-01-01

Various substoichiometric methods have been classified from a view point of the substoichiometric separation. Based upon the substoichiometric separation, phosphorus was determined substoichiometrically by a direct method, a method of carrier amount variation and a comparison method for the irradiated sample. The direct method was applied to the determination of phosphorus in orchard leaves (SRM-1571). The analytical value was 0.23 +- 0.01%. Phosphorus in orchard leaves and spinach (SRM-1570) was determined by an ordinary method which devided the sample into equal parts in the method of carrier amount variation. Analytical values of orchard leaves and spinach were 0.22 +- 0.02% and 0.56 +- 0.04%, respectively. Moreover, a new modification of the method of carrier amount variation was studied by the use of various standard samples such as red phosphorus, spinach and orchard leaves. These standard samples were also employed for the determination of phosphorus in orchard leaves and 0.21 +- 0.01% was obtained. All these results are in good agreement with the value reported by NBS. The comparison method was applied to the determination of phosphorus in a semiconductor silicon single crystal. As a result of the correction of 32 P activity induced by the secondary nuclear reaction of 30 Si, 7.9 ppb and 3.1 ppb were obtained for the phosphorus concentrations in the single crystal silicon. (author)

Modified Extraction-Free Ion-Pair Methods for the Determination of Flunarizine Dihydrochloride in Bulk Drug, Tablets, and Human Urine

Science.gov (United States)

Prashanth, K. N.; Basavaiah, K.

2018-01-01

Two simple and sensitive extraction-free spectrophotometric methods are described for the determination of flunarizine dihydrochloride. The methods are based on the ion-pair complex formation between the nitrogenous compound flunarizine (FNZ), converted from flunarizine dihydrochloride (FNH), and the acidic dye phenol red (PR), in which experimental variables were circumvented. The first method (method A) is based on the formation of a yellow-colored ion-pair complex (1:1 drug:dye) between FNZ and PR in chloroform, which is measured at 415 nm. In the second method (method B), the formed drug-dye ion-pair complex is treated with ethanolic potassium hydroxide in an ethanolic medium, and the resulting base form of the dye is measured at 580 nm. The stoichiometry of the formed ion-pair complex between the drug and dye (1:1) is determined by Job's continuous variations method, and the stability constant of the complex is also calculated. These methods quantify FNZ over the concentration ranges 5.0-70.0 in method A and 0.5-7.0 μg/mL in method B. The calculated molar absorptivities are 6.17 × 103 and 5.5 × 104 L/mol·cm-1 for method A and method B, respectively, with corresponding Sandell sensitivity values of 0.0655 and 0.0074 μg/cm2. The methods are applied to the determination of FNZ in pure drug and human urine.

Nitrogen

Science.gov (United States)

Apodaca, Lori E.

2013-01-01

The article presents an overview of the nitrogen chemical market as of July 2013, including the production of ammonia compounds. Industrial uses for ammonia include fertilizers, explosives, and plastics. Other topics include industrial capacity of U.S. ammonia producers CF Industries Holdings Inc., Koch Nitrogen Co., PCS Nitrogen, Inc., and Agrium Inc., the impact of natural gas prices on the nitrogen industry, and demand for corn crops for ethanol production.

Nitrogen diffusion in zirconium nitride

International Nuclear Information System (INIS)

Desmaison, J.G.; Smeltzer, W.W.

1977-01-01

Nitrogen diffusion in polycrystalline ZrN/sub 0.71-0.79/ spheres, 60 and 90 μm diameter, was studied by the gas-solid exchange technique using 15 N as a tracer at a nitrogen pressure of 220 torr and 1000 to 1200 0 C. These specimens were characterized by chemical analyses, density, lattice parameter, and structural measurements. The tracer diffusion coefficient can be expressed as D* (cm 2 /S) = 3.0 x 10 -10 exp (-23,000/RT). This result, when compared to a previous determination obtained in the same conditions with 254 μm thick plates, confirms that nitrogen transport in this polycrystalline solid at temperatures less than 1200 0 C is associated with a short-circuit diffusion mechanism

Nitrogen emissions from broilers measured by mass balance over eighteen consecutive flocks.

Science.gov (United States)

Coufal, C D; Chavez, C; Niemeyer, P R; Carey, J B

2006-03-01

Emission of nitrogen in the form of ammonia from poultry rearing facilities has been an important topic for the poultry industry because of concerns regarding the effects of ammonia on the environment. Sound scientific data is needed to accurately estimate air emissions from poultry operations. Many factors, such as season of the year, ambient temperature and humidity, bird health, and management practices can influence ammonia volatilization from broiler rearing facilities. Precise results are often difficult to attain from commercial facilities, particularly over long periods of time. Therefore, an experiment was conducted to determine nitrogen loss from broilers in a research facility under conditions simulating commercial production for 18 consecutive flocks. Broilers were reared to 40 to 42 d of age and fed diets obtained from a commercial broiler integrator. New rice hulls were used for litter for the first flock, and the same litter was recycled for all subsequent flocks with caked litter removed between flocks. All birds, feeds, and litter materials entering and leaving the facility were quantified, sampled, and analyzed for total nitrogen content. Nitrogen loss was calculated by the mass balance method in which loss was equal to the difference between the nitrogen inputs and the nitrogen outputs. Nitrogen partitioning as a percentage of inputs averaged 15.29, 6.84, 55.52, 1.27, and 21.08% for litter, caked litter, broiler carcasses, mortalities, and nitrogen loss, respectively, over all eighteen flocks. During the production of 18 flocks of broilers on the same recycled litter, the average nitrogen emission rate was calculated to range from 4.13 to 19.74 g of N/ kg of marketed broiler (grams of nitrogen per kilogram) and averaged 11.07 g of N/kg. Nitrogen loss was significantly (P broiler grow-out facilities varies significantly on a flock-to-flock basis.

Determining distances using asteroseismic methods

DEFF Research Database (Denmark)

Aguirre, Victor Silva; Casagrande, L.; Basu, Sarbina

2013-01-01

Asteroseismology has been extremely successful in determining the properties of stars in different evolutionary stages with a remarkable level of precision. However, to fully exploit its potential, robust methods for estimating stellar parameters are required and independent verification of the r......Asteroseismology has been extremely successful in determining the properties of stars in different evolutionary stages with a remarkable level of precision. However, to fully exploit its potential, robust methods for estimating stellar parameters are required and independent verification...... fluxes, and thus distances for field stars in a self-consistent manner. Applying our method to a sample of solar-like oscillators in the {\\it Kepler} field that have accurate {\\it Hipparcos} parallaxes, we find agreement in our distance determinations to better than 5%. Comparison with measurements...

Shock velocity in weakly ionized nitrogen, air, and argon

International Nuclear Information System (INIS)

Siefert, Nicholas S.

2007-01-01

The goal of this research was to determine the principal mechanism(s) for the shock velocity increase in weakly ionized gases. This paper reports experimental data on the propagation of spark-generated shock waves (1< Mach<3) into weakly ionized nitrogen, air, and argon glow discharges (1 < p<20 Torr). In order to distinguish between effects due solely to the presence of electrons and effects due to heating of the background gas via elastic collisions with electrons, the weakly ionized discharge was pulsed on/off. Laser deflection methods determined the shock velocity, and the electron number density was collected using a microwave hairpin resonator. In the afterglow of nitrogen, air, and argon discharges, the shock velocity first decreased, not at the characteristic time for electrons to diffuse to the walls, but rather at the characteristic time for the centerline gas temperature to equilibrate with the wall temperature. These data support the conclusion that the principal mechanism for the increase in shock velocity in weakly ionized gases is thermal heating of the neutral gas species via elastic collisions with electrons

Determination of aluminum by four analytical methods

International Nuclear Information System (INIS)

Hanson, T.J.; Smetana, K.M.

1975-11-01

Four procedures have been developed for determining the aluminum concentration in basic matrices. Atomic Absorption Spectroscopy (AAS) was the routine method of analysis. Citrate was required to complex the aluminum and eliminate matrix effects. AAS was the least accurate of the four methods studied and was adversely affected by high aluminum concentrations. The Fluoride Electrode Method was the most accurate and precise of the four methods. A Gran's Plot determination was used to determine the end point and average standard recovery was 100% +- 2%. The Thermometric Titration Method was the fastest method for determining aluminum and could also determine hydroxide concentration at the same time. Standard recoveries were 100% +- 5%. The pH Electrode Method also measures aluminum and hydroxide content simultaneously, but is less accurate and more time consuming that the thermal titration. Samples were analyzed using all four methods and results were compared to determine the strengths and weaknesses of each. On the basis of these comparisons, conclusions were drawn concerning the application of each method to our laboratory needs

Selenium determination by fluorimetric method

International Nuclear Information System (INIS)

Lavorenti, A.

1981-01-01

A fluorimetric method to determine selenium both in vegetable samples and blood serum is developed. The method consists of a radioisotope 75 Se initially in order to optimize the determination of analytical conditions. Three samples digestion processes and also some factors related to methodology is studied. The nitric-percloric digestion process for 40 samples and the analytical process is shown. (M.J.C.) [pt

Modelling nitrogen transformation and removal in mara river basin wetlands upstream of lake Victoria

Science.gov (United States)

Mayo, Aloyce W.; Muraza, Marwa; Norbert, Joel

2018-06-01

Lake Victoria, the largest lake in Africa, is a resource of social-economic potential in East Africa. This lake receives water from numerous tributaries including Mara River, which contributes about 4.8% of the total Lake water inflow. Unfortunately, Mara River basin faces environmental problems because of intensive settlement, agriculture, overgrazing in the basin and mining activities, which has lead to water pollution in the river, soil erosion and degradation, decreased soil fertility, loss of vegetation cover, decreased water infiltration capacity and increased sedimentation. One of the pollutants carried by the river includes nitrogen, which has contributed to ecological degradation of the Lake Victoria. Therefore this research work was intended to determine the effectiveness of Mara River wetland for removal of nitrogen and to establish nitrogen removal mechanisms in the wetland. To predict nitrogen removal in the wetland, the dynamics of nitrogen transformation was studied using a conceptual numerical model that takes into account of various processes in the system using STELLA II version 9.0®2006 software. Samples of model input from water, plants and sediments were taken for 45 days and were analyzed for pH, temperature, and DO in situ and chemical parameters such as NH3-N, Org-N, NO2-N, and NO3-N were analyzed in the laboratory in accordance with Standard methods. For plants, the density, dominance, biomass productivity and TN were determined and for sediments TN was analyzed. Inflow into the wetland was determined using stage-discharge relationship and was found to be 734,400 m3/day and the average wetland volume was 1,113,500 m3. Data collected by this study were used for model calibration of nitrogen transformation in this wetland while data from another wetland were used for model validation. It was found that about 37.8% of total nitrogen was removed by the wetland system largely through sedimentation (26.6%), plant uptake (6.6%) and

On the nature of the fast depolarization of muons in condensed nitrogen

International Nuclear Information System (INIS)

Duginov, V.N.; Grebinnik, V.G.; Kirillov, B.F.

1990-01-01

Temperature dependences of the depolarization rate, the muon precession initial amplitude and phase in liquid and crystalline nitrogen with the oxygen content of 10 -6 have been measured. It has been shown that muon spin relaxation parameters in nitrogen do not change at the reduction of the oxygen impurity content from 0.7x10 -4 to 10 -6 . The fast depolarization of muons in condensed nitrogen is apparently due to the formation of muonium atoms. The muon precession initial phase has been measured as a function of the perpendicular magnetic field to determine the state of short-lived muonium in nitrogen. It has been determined that muonium in nitrogen is in an excited state. 14 refs.; 3 figs

Formation of Nitrogen Bubbles During Solidification of Duplex Stainless Steels

Science.gov (United States)

Dai, Kaiju; Wang, Bo; Xue, Fei; Liu, Shanshan; Huang, Junkai; Zhang, Jieyu

2018-04-01

The nucleation and growth of nitrogen bubbles for duplex stainless steels are of great significance for the formation mechanism of bubbles during solidification. In the current study, numerical method and theoretical analysis of formula derivation were used to study the formation of nitrogen bubbles during solidification. The critical sizes of the bubble for homogeneous nucleation and heterogeneous nucleation at the solid-liquid interface during solidification were derived theoretically by the classical nucleation theory. The results show that the calculated values for the solubility of nitrogen in duplex stainless steel are in good agreement with the experimental values which are quoted by references: for example, when the temperature T = 1823 K and the nitrogen partial pressure P_{{N2 }} = 40P^{Θ} , the calculated value (0.8042 wt pct) for the solubility of Fe-12Cr alloy nitrogen in molten steel is close to the experimental value (0.780 wt pct). Moreover, the critical radii for homogeneous nucleation and heterogeneous nucleation are identical during solidification. On the one hand, with the increasing temperature or the melt depth, the critical nucleation radius of bubbles at the solid-liquid interface increases, but the bubble growth rate decreases. On the other hand, with the decreasing initial content of nitrogen or the cooling rate, the critical nucleation radius of bubbles at the solid-liquid interface increases, but the bubble growth rate decreases. Furthermore, when the melt depth is greater than the critical depth, which is determined by the technological conditions, the change in the Gibbs free energy for the nucleation is not conducive enough to form new bubbles.

Enhancement of periodate-hydrogen peroxide chemiluminescence by nitrogen doped carbon dots and its application for the determination of pyrogallol and gallic acid.

Science.gov (United States)

Shah, Syed Niaz Ali; Li, Haifang; Lin, Jin-Ming

2016-06-01

A new sensitized chemiluminescence (CL) was developed to broaden the analytical application of KIO4-H2O2 system. The nitrogen doped carbon dots (N-CDs) dramatically boosted the CL intensity of KIO4-H2O2 system which was further enriched by basic medium. In light of EPR analysis, free radical scavenging studies and CL spectra the detail mechanism for the enhancement was conferred in the presence of N-CDs and NaOH. The results suggested that CL of KIO4-H2O2 system in the presence and absence of N-CDs and NaOH proceeds via radical pathway. The enhanced CL was used for the determination of pyrogallol and gallic acid in range of 1.0×10(-4)-1.0×10(-7)M with 4.6×10(-8) and 6.1×10(-8)M limit of detection respectively. The relative standard deviation (RSD) at a concentration of 10(-5) for gallic acid and pyrogallol was 1.4% and 2.3% respectively (n=11). The attained results unveil that the present method is sensitive, faster, simpler and less costly compared to other methods and could be applied to determine polyphenols in real samples. Copyright © 2016 Elsevier B.V. All rights reserved.

Strengthening Hadfield steel welds by nitrogen alloying

International Nuclear Information System (INIS)

Efstathiou, C.; Sehitoglu, H.

2009-01-01

Strengthening Hadfield steel weld repairs by introducing nitrogen into the weld region was proven to be feasible via two welding techniques. The first technique required a pure Hadfield steel filler material to be diffusion treated in a high pressure nitrogen gas environment, and subsequently used during tungsten inert gas welding with a pure argon shielding gas. The second technique used a Hadfield steel filler material, and a 10% nitrogen containing argon shielding gas during tungsten inert gas welding. Both techniques increased the yield strength, the hardening rate, and the ultimate strength of the weld region. Using optical microscopy, scanning electron microscopy, and Auger spectroscopy, we determined that the increased strength of the weld region resulted from a combination of nitrogen alloying and microstructural refinement

Isotope investigation of nitrogen in the hydrosphere

International Nuclear Information System (INIS)

Heaton, T.H.E.

1985-01-01

Compounds of nitrogen are essential, often limiting nutrients, and the nitrogen cycle is therefore one of the most important of the earth's major elements cycles. Of all the cycles, however, the nitrogen cycle is also probably the one most influenced by human activity. This activity has resulted in the increase in reactive nitrogen compounds to such an extent that they now present major forms of pollution. Any strategies aimed at counteracting these disturbances require a better understanding of the sources and reaction processes for nitrogen compounds, and studies of natural variations in 15 N/ 14 N ratio are now being used for this purpose in all parts of the hydrosphere. This paper reviews the isotopic method for tracing sources of nitrate in ground and surface waters

Corn yield and economic return with nitrogen applied through drip tubing

Science.gov (United States)

A two year project was established to determine corn (Zea mays, L) yield response to subsurface (SSDI) and surface (SDI) drip irrigation systems at various nitrogen fertilizer rates. Nitrogen was applied through the drip system at two nitrogen levels in three split applications. Supplemental dry N ...

Distribution of total nitrogen and N-15 labelled nitrogen applied to apple trees

International Nuclear Information System (INIS)

Calvache, Marcelo.

1990-01-01

The efficiency of nitrogen fertilization from one year's application was studied in apple trees. Urea enriched with 1,5% N-15 a.e. was applied to 2 years old apple trees. Two irrigation treatments were studied, Al approx. 200mm/week and A2 approx. 100 mm/week. The distribution of N in the different parts of the trees was determined after 2 months of fertilization and after the experimental trees were excavated. The recovery of labelled fertilizer N was different in the trees in both treatments (Al = 1,2% and A2 = 3,1%). However, the distribution in the tree's parts was similar: 46% in leaves, 34% in branches and 20% in roots. We also determined that sampling only 20% of leaves at the beginning and the end of the experiment it is possible to know the quantity of nitrogen from fertilizer, without the excavation trees

Remarkable activity of nitrogen-doped hollow carbon spheres encapsulated Cu on synthesis of dimethyl carbonate: Role of effective nitrogen

Science.gov (United States)

Li, Haixia; Zhao, Jinxian; Shi, Ruina; Hao, Panpan; Liu, Shusen; Li, Zhong; Ren, Jun

2018-04-01

A critical aspect in the improvement of the catalytic performance of Cu-based catalysts for the synthesis of dimethyl carbonate (DMC) is the development of an appropriate support. In this work, nitrogen-doped hollow carbon spheres (NHCSs), with 240 nm average diameter, 17 nm shell thickness, uniform mesoporous structure and a specific surface area of 611 m2 g-1, were prepared via a two-step Stӧber method. By varying the quantity of nitrogen-containing phenols used in the preparation it has been possible to control the nitrogen content and, consequently, the sphericity of the NHCSs. It was found that perfect spheres were obtained for nitrogen contents below 5.4 wt.%. The catalysts (Cu@NHCSs) were prepared by the hydrothermal impregnation method. The catalytic activity towards DMC synthesis was notably enhanced due to the immobilization effect on Cu particles and the enhanced electron transfer effect exercised by the effective nitrogen species, including pyridinic-N and graphitic-N. When the average size of the copper nanoparticles was 7.4 nm and the nitrogen content was 4.0 wt.%, the values of space-time yield of DMC and of turnover frequency (TOF) reached 1528 mg/(g h) and 11.0 h-1, respectively. The TOF value of Cu@NHCSs was 6 times higher than non-doped Cu@Carbon (2.1 h-1). The present work introduces the potential application of nitrogen-doped carbon materials and presents a novel procedure for the preparation of catalysts for DMC synthesis.

Simple method of preparing nitrogen - doped nanosized TiO2 powders of high photocatalytic activity under visible light

International Nuclear Information System (INIS)

Nguyen Van Hung; Dang Thi Thanh Le

2014-01-01

Nitrogen-doped nanosized TiO 2 powders were prepared by a simple thermal treatment method of the mixture of titanium dioxide and urea. The prepared products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), UV-Vis diffuse reflectance spectra (UV-Vis-DRS) and Fourier transform infrared (FT-IR) spectroscopy. The results showed that the crystal structure of N-TiO 2 was a mixture of anatase and rutile phases, and the average particle size was 31 nm calculated from XRD results. The UV-vis spectra indicate an increase in absorption of visible light when compared to undoped TiO 2 . The photocatalytic activity of nitrogen-doped TiO 2 powder was evaluated by the decomposition of methylene blue under visible light irradiation. And it was found that nitrogen-doped TiO 2 powders exhibited much higher photocatalytic activity than undoped TiO 2 . Moreover, the study also showed that, the doping N atoms improve the growth of the TiO 2 crystal and phase transformation. (author)

Determination of the Fate of Dissolved Organic Nitrogen in the Three Wastewater Treatment Plants, Jordan

Science.gov (United States)

Wedyan, Mohammed; Al Harahsheh, Ahmed; Qnaisb, Esam

2016-01-01

This research aimed to assess the composition of total dissolved nitrogen (TDN) species, particularly dissolved organic nitrogen (DON), over the traditional wastewater treatment operations in three biological nutrient removal (BNR) wastewater treatment plants (WWTPs) in Jordan. It had been found that the DON percentage was up to 30% of TDN within…

Purine nitrogen index, potentially a new parameter for rapid feed evaluation in ruminants

International Nuclear Information System (INIS)

Chen, X.B.; Oerskov, E.R.; Subba, D.B.; Jayasuriya, M.C.N.

1999-01-01

The concept of a new parameter 'Purine Nitrogen Index (PNI)' for feed evaluation in ruminants is discussed. PNI refers to the ratio of purine derivative (PD) nitrogen to total nitrogen in urine. It is suggested that PNI can potentially be used as an indicator of the efficiency with which degradable dietary nitrogen is converted to microbial protein in the rumen. The excretion of PD in the urine provides an estimation of the intestinal flow of microbial protein, and therefore, PNI effectively corresponds to the amount of microbial protein produced in the rumen relative to the nitrogen loss in the urine. If a diet or a dietary regime has a high conversion efficiency, proportionally more rumen degradable nitrogen is converted to microbial protein and less nitrogen is excreted in the urine, resulting in a high PNI. Conversely, if a diet has a poor conversion efficiency, proportionally less dietary nitrogen is converted to microbial protein and more is excreted in the urine, resulting in a low PNI. Preliminary data from six experiments involving 34 sheep confirmed a positive correlation between PNI and the nitrogen conversion efficiency, and suggested that a dietary regime with a PNI lower than 0.08 for sheep appeared to be a less efficient in the production of microbial protein and have a greater loss of nitrogen in the urine. PNI can theoretically be determined in spot urine samples, and has the potential to serve as a 'dipstick' method for the rapid evaluation of ruminant feeds. However, more research with a mathematical modelling approach is required to evaluate and develop the concept further. (author)

Purine nitrogen index, potentially a new parameter for rapid feed evaluation in ruminants

Energy Technology Data Exchange (ETDEWEB)

Chen, X B; Oerskov, E R [Rowett Research Institute, Bucksburn, Aberdeen (United Kingdom); Subba, D B [Pakhribas Agricultural Centre, Dhankuta, Kathmandu (Nepal); Jayasuriya, M C.N. [International Atomic Energy Agency, Animal Production and Health Section, Vienna (Austria)

1999-06-01

The concept of a new parameter `Purine Nitrogen Index (PNI)` for feed evaluation in ruminants is discussed. PNI refers to the ratio of purine derivative (PD) nitrogen to total nitrogen in urine. It is suggested that PNI can potentially be used as an indicator of the efficiency with which degradable dietary nitrogen is converted to microbial protein in the rumen. The excretion of PD in the urine provides an estimation of the intestinal flow of microbial protein, and therefore, PNI effectively corresponds to the amount of microbial protein produced in the rumen relative to the nitrogen loss in the urine. If a diet or a dietary regime has a high conversion efficiency, proportionally more rumen degradable nitrogen is converted to microbial protein and less nitrogen is excreted in the urine, resulting in a high PNI. Conversely, if a diet has a poor conversion efficiency, proportionally less dietary nitrogen is converted to microbial protein and more is excreted in the urine, resulting in a low PNI. Preliminary data from six experiments involving 34 sheep confirmed a positive correlation between PNI and the nitrogen conversion efficiency, and suggested that a dietary regime with a PNI lower than 0.08 for sheep appeared to be a less efficient in the production of microbial protein and have a greater loss of nitrogen in the urine. PNI can theoretically be determined in spot urine samples, and has the potential to serve as a `dipstick` method for the rapid evaluation of ruminant feeds. However, more research with a mathematical modelling approach is required to evaluate and develop the concept further. (author) 15 refs, 5 figs, 4 tabs

Stable nitrogen isotopes in coastal macroalgae: geographic and anthropogenic variability.

Science.gov (United States)

Viana, Inés G; Bode, Antonio

2013-01-15

Growing human population adds to the natural nitrogen loads to coastal waters. Both anthropogenic and natural nitrogen is readily incorporated in new biomass, and these different nitrogen sources may be traced by the measurement of the ratio of stable nitrogen isotopes (δ(15)N). In this study δ(15)N was determined in two species of macroalgae (Ascophyllum nodosum and Fucus vesiculosus), and in nitrate and ammonium to determine the relative importance of anthropogenic versus natural sources of nitrogen along the coast of NW Spain. Both algal species and nitrogen sources showed similar isotopic enrichment for a given site, but algal δ(15)N was not related to either inorganic nitrogen concentrations or δ(15)N in the water samples. The latter suggests that inorganic nitrogen inputs are variable and do not always leave an isotopic trace in macroalgae. However, a significant linear decrease in macroalgal δ(15)N along the coast is consistent with the differential effect of upwelling. Besides this geographic variability, the influence of anthropogenic nitrogen sources is evidenced by higher δ(15)N in macroalgae from rias and estuaries compared to those from open coastal areas and in areas with more than 15×10(3) inhabitants in the watershed. These results indicate that, in contrast with other studies, macroalgal δ(15)N is not simply related to either inorganic nitrogen concentrations or human population size but depends on other factors as the upwelling or the efficiency of local waste treatment systems. Copyright © 2012 Elsevier B.V. All rights reserved.

15-30 Effect of Weed Management Methods and Nitrogen Fertilizer

African Journals Online (AJOL)

tosheba

Nitrogen Use Efficiency of Bread Wheat (Triticum aestivum L.) in Southern Ethiopia. Tamado Tana1*, Dawit ... in Ethiopia, dominating food habits and dietary practices, and is known .... Nationalities and People's Regional State. 2.6. ..... Page 7 ...

Identifying organic nitrogen compounds in Rocky Mountain National Park aerosols

Science.gov (United States)

Beem, K. B.; Desyaterik, Y.; Ozel, M. Z.; Hamilton, J. F.; Collett, J. L.

2010-12-01

Nitrogen deposition is an important issue in Rocky Mountain National Park (RMNP). While inorganic nitrogen contributions to the ecosystems in this area have been studied, the sources of organic nitrogen are still largely unknown. To better understand the potential sources of organic nitrogen, filter samples were collected and analyzed for organic nitrogen species. Samples were collected in RMNP using a Thermo Fisher Scientific TSP (total suspended particulate) high-volume sampler with a PM2.5 impactor plate from April - November of 2008. The samples presented the opportunity to compare two different methods for identification of individual organic nitrogen species. The first type of analysis was performed with a comprehensive two dimensional gas chromatography (GCxGC) system using a nitrogen chemiluminescence detector (NCD). The filter samples were spiked with propanil in dichloromethane to use as an internal standard and were then extracted in water followed by solid phase extraction. The GCxGC system was comprised of a volatility based separation (DB5 column) followed by a polarity based separation (RXI-17 column). A NCD was used to specifically detect nitrogen compounds and remove the complex background matrix. Individual standards were used to identify peaks by comparing retention times. This method has the added benefit of an equimolar response for nitrogen so only a single calibration is needed for all species. In the second analysis, a portion of the same filter samples were extracted in DI water and analyzed with liquid chromatography coupled with mass spectroscopy (LC/MS). The separation was performed using a C18 column and a water-methanol gradient elution. Electrospray ionization into a time of flight mass spectrometer was used for detection. High accuracy mass measurement allowed unambiguous assignments of elemental composition of resulting ions. Positive and negative polarities were used since amines tend to show up in positive mode and nitrates in

Determination of nitrogen in zirconium by charged-particle activation analysis

Energy Technology Data Exchange (ETDEWEB)

Strijckmans, K; Mortier, R; Vandecasteele, C; Hoste, J [Ghent Rijksuniversiteit (Belgium)

1982-01-01

The determination of nitrogen in zirconium by charged-particle activation analysis is described. The /sup 14/N(..cap alpha.., ..cap alpha..n)/sup 13/N and the /sup 14/N(p, ..cap alpha..)/sup 11/C reactions were used. The /sup 13/N activity was separated from matrix activity as ammonia by steam-distillation after dissolution of the sample in dilute hydrofluoric acid.The /sup 11/C activity was separated as carbon dioxide by dissolution of the sample in a mixture of concentrated sulphuric acid, sodium fluoride and potassium periodate, followed by oxidation of the evolved gases with a copper oxide-iron oxide-kaolin mixture and trapping of the carbon dioxide in dilute sodium hydroxide solution. The chemical yield of both separations was investigated. The nuclear interference of boron can be neglected, in view of the low boron content. Alpha- and protonactivation yielded the following results for BCR reference materials (alpha-activation results first): CRM 21: 24.6 +- 3.3 and 25.9 +- 0.8 ..mu..g/g (certified value: 26.4 +- 2.5 ..mu..g/g);CRM 56: 12.0 +- 1.1 and 10.5 +- 0.3 ..mu..g/g (certified value: 11.7 +- 1.7 ..mu..g/g); CRM 57: 11.2 +- 0.3 ..mu..g/g (alpha/activation) (certified value: 11.9 +- 1.8 ..mu..g/g).

Forest fuel reduces the nitrogen load - calculations of nitrogen flows

International Nuclear Information System (INIS)

Burstroem, F.; Johansson, Jan.

1995-12-01

Nitrogen deposition in Sweden has increased strongly during recent decades, particularly in southern Sweden. Nitrogen appears to be largely accumulated in biomass and in the soil. It is therefore desirable to check the accumulation of nitrogen in the forest. The most suitable way of doing this is to remove more nitrogen-rich biomass from the forest, i.e., increase the removal of felling residues from final fellings and cleanings. An ecological condition for intensive removal of fuel is that the ashes are returned. The critical load for nitrogen, CL(N), indicates the level of nitrogen deposition that the forest can withstand without leading to ecological changes. Today, nitrogen deposition is higher than the CL(N) in almost all of Sweden. CL(N) is calculated in such a manner that nitrogen deposition should largely be balanced by nitrogen losses through harvesting during a forest rotation. The value of CL(N) thus largely depends on how much nitrogen is removed with the harvested biomass. When both stems and felling residues are harvested, the CL(N) is about three times higher than in conventional forestry. The increase is directly related to the amount of nitrogen in the removed biofuel. Use of biofuel also causes a certain amount of nitrogen emissions. From the environmental viewpoint there is no difference between the sources of the nitrogen compounds. An analysis of the entire fuel chain shows that, compared with the amount of nitrogen removed from the forest with the fuel, about 5 % will be emitted as nitrogen oxides or ammonia during combustion, and a further ca 5 % during handling and transports. A net amount of about 90 % of biomass nitrogen is removed from the system and becomes inert nitrogen (N 2 ). 60 refs, 3 figs, 4 tabs, 11 appendices

Nitrogen Isotope Evidence for a Shift in Eastern Beringian Nitrogen Cycle after the Terminal Pleistocene

Science.gov (United States)

Tahmasebi, F.; Longstaffe, F. J.; Zazula, G.

2016-12-01

The loess deposits of eastern Beringia, a region in North America between 60° and 70°N latitude and bounded by Chukchi Sea to the west and the Mackenzie River to the east, are a magnificent repository of Late Pleistocene megafauna fossils. The stable carbon and nitrogen isotope compositions of these fossils are measured to determine the paleodiet of these animals, and hence the paleoenvironment of this ecosystem during the Quaternary. For this approach to be most successful, however, requires consideration of possible changes in nutrient cycling and hence the carbon and nitrogen isotopic compositions of vegetation in this ecosystem. To test for such a shift following the terminal Pleistocene, we analyzed the stable carbon and nitrogen isotope compositions of modern plants and bone collagen of Arctic ground squirrels from Yukon Territory, and fossil plants and bones recovered from Late Pleistocene fossil Arctic ground squirrel nests. The data for modern samples provided a measure of the isotopic fractionation between ground squirrel bone collagen and their diet. The over-wintering isotopic effect of decay on typical forage grasses was also measured to evaluate its role in determining fossil plant isotopic compositions. The grasses showed only a minor change ( 0-1 ‰) in carbon isotope composition, but a major change ( 2-10 ‰) in nitrogen isotope composition over the 317-day experiment. Based on the modern carbon isotope fractionation between ground squirrel bone collagen and their diet, the modern vegetation carbon isotopic baseline provides a suitable proxy for the Late Pleistocene of eastern Beringia, after accounting for the Suess effect. However, the predicted nitrogen isotope composition of vegetation comprising the diet of fossil ground squirrels remains 2.5 ‰ higher than modern grasslands in this area, even after accounting for possible N-15 enrichment during decay. This result suggests a change in N cycling in this region since the Late Pleistocene.

Estimating Canopy Nitrogen Concentration in Sugarcane Using Field Imaging Spectroscopy

Directory of Open Access Journals (Sweden)

Marc Souris

2012-06-01

Full Text Available The retrieval of nutrient concentration in sugarcane through hyperspectral remote sensing is widely known to be affected by canopy architecture. The goal of this research was to develop an estimation model that could explain the nitrogen variations in sugarcane with combined cultivars. Reflectance spectra were measured over the sugarcane canopy using a field spectroradiometer. The models were calibrated by a vegetation index and multiple linear regression. The original reflectance was transformed into a First-Derivative Spectrum (FDS and two absorption features. The results indicated that the sensitive spectral wavelengths for quantifying nitrogen content existed mainly in the visible, red edge and far near-infrared regions of the electromagnetic spectrum. Normalized Differential Index (NDI based on FDS_(750/700 and Ratio Spectral Index (RVI based on FDS_(724/700 are best suited for characterizing the nitrogen concentration. The modified estimation model, generated by the Stepwise Multiple Linear Regression (SMLR technique from FDS centered at 410, 426, 720, 754, and 1,216 nm, yielded the highest correlation coefficient value of 0.86 and Root Mean Square Error of the Estimate (RMSE value of 0.033%N (n = 90 with nitrogen concentration in sugarcane. The results of this research demonstrated that the estimation model developed by SMLR yielded a higher correlation coefficient with nitrogen content than the model computed by narrow vegetation indices. The strong correlation between measured and estimated nitrogen concentration indicated that the methods proposed in this study could be used for the reliable diagnosis of nitrogen quantity in sugarcane. Finally, the success of the field spectroscopy used for estimating the nutrient quality of sugarcane allowed an additional experiment using the polar orbiting hyperspectral data for the timely determination of crop nutrient status in rangelands without any requirement of prior

Nitrogen turnover of three different agricultural soils determined by 15N triple labelling

Science.gov (United States)

Fiedler, Sebastian R.; Kleineidam, Kristina; Strasilla, Nicol; Schlüter, Steffen; Reent Köster, Jan; Well, Reinhard; Müller, Christoph; Wrage-Mönnig, Nicole

2017-04-01

To meet the demand for data to improve existing N turnover models and to evaluate the effect of different soil physical properties on gross nitrogen (N) transformation rates, we investigated two arable soils and a grassland soil after addition of ammonium nitrate (NH4NO3), where either ammonium (NH4+), or nitrate (NO3-), or both pools have been labelled with 15N at 60 atom% excess (triple 15N tracing method). Besides NH4+, NO3- and nitrite (NO2-) contents with their respective 15N enrichment, nitrous oxide (N2O) and dinitrogen (N2) fluxes have been determined. Each soil was adjusted to 60 % of maximum water holding capacity and pre-incubated at 20˚ C for two weeks. After application of the differently labelled N fertilizer, the soils were further incubated at 20˚ C under aerobic conditions in a He-N2-O2 atmosphere (21 % O2, 76 He, 2% N2) to increase the sensitivity of N2 rates via the 15N gas flux method. Over a 2 week period soil N pools were quantified by 2 M KCl extraction (adjusted to pH 7 to prevent nitrite losses) (Stevens and Laughlin, 1995) and N gas fluxes were measured by gas chromatography in combination with IRMS. Here, we present the pool sizes and fluxes as well as the 15N enrichments during the study. Results are discussed in light of the soil differences that were responsible for the difference in gross N dynamics quantified by the 15N tracing model Ntrace (Müller et al., 2007). References Müller, C., T. Rütting, J. Kattge, R.J. Laughlin, and R.J. Stevens, (2007) Estimation of parameters in complex 15N tracing models by Monte Carlo sampling. Soil Biology & Biochemistry. 39(3): p. 715-726. Stevens, R.J. and R.J. Laughlin, (1995) Nitrite transformations during soil extraction with potassium chloride. Soil Science Society of America Journal. 59(3): p. 933-938.

Specific cooling capacity of liquid nitrogen

Science.gov (United States)

Kilgore, R. A.; Adcock, J. B.

1977-01-01

The assumed cooling process and the method used to calculate the specific cooling capacity of liquid nitrogen are described, and the simple equation fitted to the calculated specific cooling capacity data, together with the graphical form calculated values of the specific cooling capacity of nitrogen for stagnation temperatures from saturation to 350 K and stagnation pressures from 1 to 10 atmospheres, are given.

Cycling of grain legume residue nitrogen

DEFF Research Database (Denmark)

Jensen, E.S.

1995-01-01

Symbiotic nitrogen fixation by legumes is the main input of nitrogen in ecological agriculture. The cycling of N-15-labelled mature pea (Pisum sativum L.) residues was studied during three years in small field plots and lysimeters. The residual organic labelled N declined rapidly during the initial...... management methods in order to conserve grain legume residue N sources within the soil-plant system....

A Generalizable Top-Down Nanostructuring Method of Bulk Oxides: Sequential Oxygen-Nitrogen Exchange Reaction.

Science.gov (United States)

Lee, Lanlee; Kang, Byungwuk; Han, Suyoung; Kim, Hee-Eun; Lee, Moo Dong; Bang, Jin Ho

2018-05-27

A thermal reaction route that induces grain fracture instead of grain growth is devised and developed as a top-down approach to prepare nanostructured oxides from bulk solids. This novel synthesis approach, referred to as the sequential oxygen-nitrogen exchange (SONE) reaction, exploits the reversible anion exchange between oxygen and nitrogen in oxides that is driven by a simple two-step thermal treatment in ammonia and air. Internal stress developed by significant structural rearrangement via the formation of (oxy)nitride and the creation of oxygen vacancies and their subsequent combination into nanopores transforms bulk solid oxides into nanostructured oxides. The SONE reaction can be applicable to most transition metal oxides, and when utilized in a lithium-ion battery, the produced nanostructured materials are superior to their bulk counterparts and even comparable to those produced by conventional bottom-up approaches. Given its simplicity and scalability, this synthesis method could open a new avenue to the development of high-performance nanostructured electrode materials that can meet the industrial demand of cost-effectiveness for mass production. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Species ecology determines the role of nitrogen nutrition in the frost tolerance of pine seedlings.

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Toca, Andrei; Oliet, Juan A; Villar-Salvador, Pedro; Maroto, Judit; Jacobs, Douglass F

2018-01-01

Frost determines the evolution and distribution of plants in temperate and cold regions. Several environmental factors can influence frost acclimation of woody plants but the magnitude and direction of the effect of nitrogen (N) availability is controversial. We studied the effect of N availability on root and shoot frost tolerance in mid-fall and in winter in seedlings of four pines of contrasting ecology: Pinus nigra J.F. Arnold, P. pinaster Ait., P. pinea L. and P. halepensis Mill.. Organ N and soluble sugar concentration, and timing of cessation of shoot elongation were measured to assess the physiological mechanisms underlying frost acclimation. Nitrogen was supplied at high and low rates only during the pre-hardening period and at a moderate N rate during hardening in the fall. Shoot frost tolerance increased over winter while root frost tolerance did not change in any species. Pre-hardening N availability affected the frost tolerance of both roots and shoots, although the effect was species-specific: high N reduced the overall root and shoot frost tolerance in P. pinea and P. halepensis, and increased the frost tolerance in P. nigra, but had no effect in P. pinaster. Nitrogen supply in the fall consistently increased frost tolerance in all species. Differences in frost tolerance among species and N treatments were not explained by variations in organ N or soluble carbohydrate concentration, nor by timing of cessation of shoot elongation; however, the most frost tolerant species ceased elongation earlier than the least frost tolerant species. Despite the close phylogenetic relatedness of the studied species, the effect of N availability on seedling frost tolerance differed among species, indicating that species ecology (especially frost acclimation physiology) and timing of N supply drives the effect of N availability on frost tolerance of pine species. © The Author(s) 2017. Published by Oxford University Press. All rights reserved. For Permissions, please

A case study of the relative effects of power plant nitrogen oxides and sulfur dioxide emission reductions on atmospheric nitrogen deposition.

Science.gov (United States)

Vijayaraghavan, Krish; Seigneur, Christian; Bronson, Rochelle; Chen, Shu-Yun; Karamchandani, Prakash; Walters, Justin T; Jansen, John J; Brandmeyer, Jo Ellen; Knipping, Eladio M

2010-03-01

The contrasting effects of point source nitrogen oxides (NOx) and sulfur dioxide (SO2) air emission reductions on regional atmospheric nitrogen deposition are analyzed for the case study of a coal-fired power plant in the southeastern United States. The effect of potential emission reductions at the plant on nitrogen deposition to Escambia Bay and its watershed on the Florida-Alabama border is simulated using the three-dimensional Eulerian Community Multiscale Air Quality (CMAQ) model. A method to quantify the relative and individual effects of NOx versus SO2 controls on nitrogen deposition using air quality modeling results obtained from the simultaneous application of NOx and SO2 emission controls is presented and discussed using the results from CMAQ simulations conducted with NOx-only and SO2-only emission reductions; the method applies only to cases in which ambient inorganic nitrate is present mostly in the gas phase; that is, in the form of gaseous nitric acid (HNO3). In such instances, the individual effects of NOx and SO2 controls on nitrogen deposition can be approximated by the effects of combined NOx + SO2 controls on the deposition of NOy, (the sum of oxidized nitrogen species) and reduced nitrogen species (NHx), respectively. The benefit of controls at the plant in terms of the decrease in nitrogen deposition to Escambia Bay and watershed is less than 6% of the overall benefit due to regional Clean Air Interstate Rule (CAIR) controls.

Carbon and nitrogen isotopic signatures and nitrogen profile to identify adulteration in organic fertilizers.

Science.gov (United States)

Verenitch, Sergei; Mazumder, Asit

2012-08-29

Recently it has been shown that stable isotopes of nitrogen can be used to discriminate between organic and synthetic fertilizers, but the robustness of the approach is questionable. This work developed a comprehensive method that is far more robust in identifying an adulteration of organic nitrogen fertilizers. Organic fertilizers of various types (manures, composts, blood meal, bone meal, fish meal, products of poultry and plant productions, molasses and seaweed based, and others) available on the North American market were analyzed to reveal the most sensitive criteria as well as their quantitative ranges, which can be used in their authentication. Organic nitrogen fertilizers of known origins with a wide δ(15)N range between -0.55 and 28.85‰ (n = 1258) were characterized for C and N content, δ(13)C, δ(15)N, viscosity, pH, and nitrogen profile (urea, ammonia, organic N, water insoluble N, and NO3). A statistically significant data set of characterized unique organic nitrogen fertilizers (n = 335) of various known origins has been assembled. Deliberately adulterated samples of different types of organic fertilizers mixed with synthetic fertilizers at a wide range of proportions have been used to develop the quantitative critical characteristics of organic fertilizers as the key indicators of their adulteration. Statistical analysis based on the discriminant functions of the quantitative critical characteristics of organic nitrogen fertilizers from 14 different source materials revealed a very high average rate of correct classification. The developed methodology has been successfully used as a source identification tool for numerous commercial nitrogen fertilizers available on the North American market.

Short-term experiments for determination of the relative phytotoxicity of nitrogen dioxide

Energy Technology Data Exchange (ETDEWEB)

van Haut, H.

1975-01-01

In short-term experiments, the relative phytotoxicity of nitrogen dioxide was determined for 60 types of plants by comparing it with that of sulfur dioxide. The plants, which included crop and garden plants such as alfalfa, clover, barley, lettuce, carrots, parsley, radishes, onions, beans, and tobacco; ornamental plants, such as roses, dahlias, and gladioli; and coniferous and deciduous trees, such as pines, spruces, birches, and maples, were exposed to the two gases in parallel experiments. The exposure concentrations were 5 to 20 mg NO/sub 2/ cu/m air and 1.5 to 4 mg SO/sub 2//cu m air. Taking the average concentration ratio of SO/sub 2/ to NO/sub 2/ of 1/3.5 and an SO/sub 2/ long-term value of 0.1 mg SO/sub 2//cu m, an average value of 0.35 mg NO/sub 2//cu m of air was obtained for the vegetation half-year. The average value obtained for a 30-min period was 0.80 mg NO/sub 2//cu m of air.

Economic Tools for Managing Nitrogen in Coastal Watersheds ...

Science.gov (United States)

Watershed managers are interested in using economics to communicate the value of estuarine resources to the wider community, determine the most cost-effective means to reduce nitrogen pollution, and evaluate the benefits of taking action to improve coastal ecosystems. We spoke to coastal watershed managers who had commissioned economic studies and found that they were largely satisfied with the information and their ability to communicate the importance of coastal ecosystems. However, while managers were able to use these studies as communication tools, methods used in some studies were inconsistent with what some economists consider best practices. In addition, many watershed managers are grappling with how to implement nitrogen management activities in a way that is both cost-effective and achieves environmental goals, while maintaining public support. These and other issues led to this project. Our intent is to provide information to watershed managers and others interested in watershed management – such as National Estuary Programs, local governments, or nongovernmental organizations – on economic tools for managing nitrogen in coastal watersheds, and to economists and other analysts who are interested in assisting them in meeting their needs. Watershed management requires balancing scientific, political, and social issues to solve environmental problems. This document summarizes questions that watershed managers have about using economic analysis, and g

Fluxes of oxidised and reduced nitrogen above a mixed coniferous forest exposed to various nitrogen emission sources

Energy Technology Data Exchange (ETDEWEB)

Neirynck, J. [Research Institute for Nature and Forest, Gaverstraat 4, B-9500 Geraardsbergen (Belgium)]. E-mail: johan.neirynck@inbo.be; Kowalski, A.S. [Departamento de Fisica Aplicida, Facultad de Ciencias, Universidad de Granada, Calle Fuentenueva, SP-18071 Granada (Spain); Carrara, A. [Fundacion CEAM, Parque Technologico, Calle Charles H. Darwin 14, SP-46980 Paterna (Valencia) (Spain); Genouw, G. [Research Institute for Nature and Forest, Gaverstraat 4, B-9500 Geraardsbergen (Belgium); Berghmans, P. [Flemish Institute for Technological Research, Boeretang 200, B-2400 Mol (Belgium); Ceulemans, R. [Department of Biology, University of Antwerp, Universiteitsplein 1, B-2610 Wilrijk (Antwerp) (Belgium)

2007-09-15

Concentrations of nitrogen gases (NH{sub 3}, NO{sub 2}, NO, HONO and HNO{sub 3}) and particles (pNH{sub 4} and pNO{sub 3}) were measured over a mixed coniferous forest impacted by high nitrogen loads. Nitrogen dioxide (NO{sub 2}) represented the main nitrogen form, followed by nitric oxide (NO) and ammonia (NH{sub 3}). A combination of gradient method (NH{sub 3} and NO {sub x} ) and resistance modelling techniques (HNO{sub 3}, HONO, pNH{sub 4} and pNO{sub 3}) was used to calculate dry deposition of nitrogen compounds. Net flux of NH{sub 3} amounted to -64 ng N m{sup -2} s{sup -1} over the measuring period. Net fluxes of NO {sub x} were upward (8.5 ng N m{sup -2} s{sup -1}) with highest emission in the morning. Fluxes of other gases or aerosols substantially contributed to dry deposition. Total nitrogen deposition was estimated at -48 kg N ha{sup -1} yr{sup -1} and consisted for almost 80% of NH {sub x} . Comparison of throughfall nitrogen with total deposition suggested substantial uptake of reduced N ({+-}15 kg N ha{sup -1} yr{sup -1}) within the canopy. - Reduced nitrogen was found to be the main contributor to total deposition which was predominantly governed by dry deposition.

A method for the determination of potassium concentration in organic tissue samples

International Nuclear Information System (INIS)

Maciel, A.C.A.

1976-12-01

An original method has been developed to detect small variations of potassium in several samples of organic tissue. These variations are relative to elements that are biologically representative, such as carbon, oxygen, and nitrogen. The samples are irradiated with a beam of protons from a Van de Graaff accelerator (4MV). Vacancies are created in the K-shell of potassium, and x-rays are emitted when these vacancies are filled with outer electrons. These X-rays and the protons elastically scattered by the nuclei of carbon, nitrogen and oxygen are detected and their energy spectra are analysed by computer programs especially elaborated for this purpose. A technique for routine preparation of samples in the laboratory was developed including the production of aluminum support layers, and the preparation of organic tissue samples with a low temperature microtome. The unique features of this method are that it does not destroy the tissue, permitting further analysis with the microscope, and the normalization of the amount of potassium using other elements (C,O,N) instead of the total mass of the sample. (Author) [pt

Protein Losses and Urea Nitrogen Underestimate Total Nitrogen Losses in Peritoneal Dialysis and Hemodialysis Patients.

Science.gov (United States)

Salame, Clara; Eaton, Simon; Grimble, George; Davenport, Andrew

2018-04-28

Muscle wasting is associated with increased mortality and is commonly reported in dialysis patients. Hemodialysis (HD) and peritoneal dialysis (PD) treatments lead to protein losses in effluent dialysate. We wished to determine whether changes in current dialysis practice had increased therapy-associated nitrogen losses. Cross-sectional cohort study. Measurement of total protein, urea and total nitrogen in effluent dialysate from 24-hour collections from PD patients, and during haemodiafiltration (HDF) and haemodialysis (HD) sessions. One hundred eight adult dialysis patients. Peritoneal dialysis, high-flux haemodialysis and haemodiafiltration. Total nitrogen and protein losses. Dialysate protein losses were measured in 68 PD and 40 HD patients. Sessional losses of urea (13.9 [9.2-21.1] vs. 4.8 [2.8-7.8] g); protein (8.6 [7.2-11.1] vs. 6.7 [3.9-11.1] g); and nitrogen (11.5 [8.7-17.7] vs. 4.9 [2.6-9.5] g) were all greater for HD than PD, P losses were lower with HD 25.9 (21.5-33.4) versus 46.6 (27-77.6) g/week, but nitrogen losses were similar. We found no difference between high-flux HD and HDF: urea (13.5 [8.8-20.6] vs. 15.3 [10.5-25.5] g); protein (8.8 [7.3-12.2] vs. 7.6 [5.8-9.0] g); and total nitrogen (11.6 [8.3-17.3] vs. 10.8 [8.9-22.5] g). Urea nitrogen (UN) only accounted for 45.1 (38.3-51.0)% PD and 63.0 (55.3-62.4)% HD of total nitrogen losses. Although sessional losses of protein and UN were greater with HD, weekly losses were similar between modalities. We found no differences between HD and HDF. However, total nitrogen losses were much greater than the combination of protein and UN, suggesting greater nutritional losses with dialysis than previously reported. Copyright © 2018 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

Coupled effects of light and nitrogen source on the urea cycle and nitrogen metabolism over a diel cycle in the marine diatom Thalassiosira pseudonana.

Science.gov (United States)

Bender, Sara J; Parker, Micaela S; Armbrust, E Virginia

2012-03-01

Diatoms are photoautotrophic organisms capable of growing on a variety of inorganic and organic nitrogen sources. Discovery of a complete urea cycle in diatoms was surprising, as this pathway commonly functions in heterotrophic organisms to rid cells of waste nitrogen. To determine how the urea cycle is integrated into cellular nitrogen metabolism and energy management, the centric diatom Thalassiosira pseudonana was maintained in semi-continuous batch cultures on nitrate, ammonium, or urea as the sole nitrogen source, under a 16: 8 light: dark cycle and at light intensities that were low, saturating, or high for growth. Steady-state transcript levels were determined for genes encoding enzymes linked to the urea cycle, urea hydrolysis, glutamine synthesis, pyrimidine synthesis, photorespiration, and energy storage. Transcript abundances were significantly affected by nitrogen source, light intensity and a diel cycle. The impact of N source on differential transcript accumulation was most apparent under the highest light intensity. Models of cellular metabolism under high light were developed based on changes in transcript abundance and predicted enzyme localizations. We hypothesize that the urea cycle is integrated into nitrogen metabolism through its connection to glutamine and in the eventual production of urea. These findings have important implications for nitrogen flow in the cell over diel cycles at surface ocean irradiances. Copyright © 2011 Elsevier GmbH. All rights reserved.

Nitrogen balance in grasses of the genus Brachiaria

International Nuclear Information System (INIS)

Loureiro, M. de F.

1985-01-01

A 15 N aided nitrogen balance experiment was performed in posts in the greenhouse to quantify the contribution of biological nitrogen fixation to four species of Brachiaria grow in two soils. The effects of adding molybdenum to the pots was also investigated. Among various methods for the analysis of total nitrogen in plant material and soil, a technique utilizing a pre-digestion with Devarda's alloy was found to be most efficient. In the nitrogen analyses the sample size and particle size were found to be factors limiting the precision of the analyses. In an analysis of the sources of error, the sampling of the soil was found to be the greatest source of variation on the nitrogen balance. (author)

A comparative evaluation of nitrogen compounds in petroleum distillates

Energy Technology Data Exchange (ETDEWEB)

Singh, Dheer; Chopra, Anju; Patel, Mitra Bhanu; Sarpal, Amarjit Singh [Indian Oil Corporation Limited, Faridabad (India). Research and Development Centre

2011-07-15

Although the concentration of nitrogen compounds in crude oil is relatively low, they can become more concentrated in petroleum distillates and poison the catalysts used in refining processes. They cause undesirable deposits, color formation and odor in products; they also contribute to air pollution and some are highly carcinogenic. The poisoned catalyst becomes deactivated for hydrodesulfurization and unable to remove sulfur from middle distillates. In order to understand the effect on catalytic processes, it is desirable to identify the nitrogen compounds in various petroleum distillates. This paper compares the nitrogen species profiles in different petroleum distillates using a nitrogen chemiluminescence detector. In addition, four different petroleum distillate samples from different refineries were analyzed to find the variation in their nitrogen profiles. The nitrogen compounds in petroleum distillate samples were identified as anilines, quinolines, indoles, and carbazoles and their alkyl derivatives. Quantitation was carried out against known reference standards. The quantitative data were compared to the total nitrogen content determined by elemental analysis. (orig.)

Stable nitrogen isotopes in coastal macroalgae: Geographic and anthropogenic variability

International Nuclear Information System (INIS)

Viana, Inés G.; Bode, Antonio

2013-01-01

Growing human population adds to the natural nitrogen loads to coastal waters. Both anthropogenic and natural nitrogen is readily incorporated in new biomass, and these different nitrogen sources may be traced by the measurement of the ratio of stable nitrogen isotopes (δ 15 N). In this study δ 15 N was determined in two species of macroalgae (Ascophyllum nodosum and Fucus vesiculosus), and in nitrate and ammonium to determine the relative importance of anthropogenic versus natural sources of nitrogen along the coast of NW Spain. Both algal species and nitrogen sources showed similar isotopic enrichment for a given site, but algal δ 15 N was not related to either inorganic nitrogen concentrations or δ 15 N in the water samples. The latter suggests that inorganic nitrogen inputs are variable and do not always leave an isotopic trace in macroalgae. However, a significant linear decrease in macroalgal δ 15 N along the coast is consistent with the differential effect of upwelling. Besides this geographic variability, the influence of anthropogenic nitrogen sources is evidenced by higher δ 15 N in macroalgae from rias and estuaries compared to those from open coastal areas and in areas with more than 15 × 10 3 inhabitants in the watershed. These results indicate that, in contrast with other studies, macroalgal δ 15 N is not simply related to either inorganic nitrogen concentrations or human population size but depends on other factors as the upwelling or the efficiency of local waste treatment systems. - Highlights: ► Anthropogenic versus upwelling nitrogen effect on macroalgal δ 15 N was studied. ► The influence of populations and upwelling has not been made before on macroalgal δ 15 N. ► Natural variability has not been taken into account in most biomonitoring studies. ► Upwelling explains most of the variability in δ 15 N in macroalgae

A comparison of total bound nitrogen with the sum of inorganic nitrogen in the present partice in the German Water Regulation Act for monitoring of nitrogen compounds; Ein Vergleich des gesamten gebundenen Stickstoffs mit der Summe des anorganischen Stickstoffs in der derzeitigen Gesetzespraxis zur Ueberwachung auf Stickstoffverbindungen

Energy Technology Data Exchange (ETDEWEB)

Rinne, D.; Seckert-Knopp, W. [Landesamt fuer Wasserwirtschaft Rheinland-Pfalz, Mainz (Germany)

1997-11-01

The results of the analysis of nitrate, nitrite, ammonia, and total bound nitrogen (TN{sub b}) from 331 samples of municipal and 322 samples of industrial waste water effluents were compiled in the years 1990 to 1994. These data were evaluated due to - the comparison of the sum of inorganic nitrogen ({Sigma} N{sub anorg.}) of nitrate, nitrite, and ammonia to TN{sub b} in view of a planned exchange in the German Waste Water Regulation Act - the calculation of organic bound nitrogen (N{sub org.}) - the usefulness to generate sufficient data for balancing the `content of nitrogen` in water systems. The results of our investigations are: The analytical results from the sum of inorganic nitrogen and TN{sub b} are in very good agreement. In most cases the TN{sub b} values were higher than those of {Sigma} N{sub anorg.} This is plausible because most samples contain a certain amount of organic bound nitrogen. Therefore the differences between the results of this two analytical parameters should express the term `organic bound nitrogen` (N{sub org.}). This substraction is an excellent method to estimate this value without a further analytical procedure. The data from our investigation underline this quite clearly. In contrary to the determination of the single compounds ammonia, nitrate, and nitrite the TN{sub b} as a sum parameter is fast, instrument based, can be automated and shows a sufficient limit of determination. This method allows the evaluation of a high data density for water monitoring and balancing the `content of nitrogen` in water systems. A further advantage is the minimizing of errors when applying only one analytical method instead of three. (orig.) [Deutsch] Die Analysenergebnisse der Parameter Nitrit, Nitrat, Ammonium sowie die davon abgeleiteten Parameter `Summe anorganischer Stickstoff` ({Sigma} N{sub anorg.}) und `gesamter gebundener Stickstoff` (TN{sub b}) wurden fuer 331 Proben kommunaler und 322 Proben industrieller Abwasseranlagen aus den Jahren

Do lichens have "memory" of their native nitrogen environment?

Science.gov (United States)

Munzi, Silvana; Loppi, Stefano; Cruz, Cristina; Branquinho, Cristina

2011-02-01

This study aimed to deepen the knowledge about intraspecific mechanisms regulating nitrogen tolerance in lichens to wet nitrogen deposition. Thalli of the nitrophilous lichen Xanthoria parietina were collected from environments with different nitrogen availabilities and immersed in 80 mL of ammonium sulphate (NH₄)₂SO₄ solutions with distinct concentrations (0, 0.025, 0.05 and 0.25 M) for 5 h per day during 3 days in a week. After each soaking event, lichens were air dried. After each treatment, maximal PSII efficiency, localization of ammonium ions, concentrations of K+ and Mg²+ and thalli buffer capacity were determined. Our results show that lichens are marked by their native nitrogen environment, since there were important differences between the physiological responses of X. parietina thalli previously grown in an area with high nitrogen deposition (nitrogen emissions of ca. 13,000 t/year) and those previously grown in an unpolluted area (nitrogen emissions of ca. 500 t/year). Greater N availability seems to enable X. parietina to cope better with the effects of nitrogen pollution.

Calculation methods for determining dose equivalent

International Nuclear Information System (INIS)

Endres, G.W.R.; Tanner, J.E.; Scherpelz, R.I.; Hadlock, D.E.

1987-11-01

A series of calculations of neutron fluence as a function of energy in an anthropomorphic phantom was performed to develop a system for determining effective dose equivalent for external radiation sources. Critical organ dose equivalents are calculated and effective dose equivalents are determined using ICRP-26 [1] methods. Quality factors based on both present definitions and ICRP-40 definitions are used in the analysis. The results of these calculations are presented and discussed. The effective dose equivalent determined using ICRP-26 methods is significantly smaller than the dose equivalent determined by traditional methods. No existing personnel dosimeter or health physics instrument can determine effective dose equivalent. At the present time, the conversion of dosimeter response to dose equivalent is based on calculations for maximal or ''cap'' values using homogeneous spherical or cylindrical phantoms. The evaluated dose equivalent is, therefore, a poor approximation of the effective dose equivalent as defined by ICRP Publication 26. 3 refs., 2 figs., 1 tab

Comparison of 14 MeV neutron activation analysis and competitive methods for determination of oxygen, nitrogen, silicon, fluorine and other elements

International Nuclear Information System (INIS)

Bild, R.W.

1986-01-01

14 MeV neutron activation analysis (14 MeV NAA) makes use of small particle accelerators to produce 14 MeV neutrons from the D-T reaction. The neutrons produce radioactive isotopes in samples by the reactions (n,p), (n,2n) and (n,α). Gamma rays emitted are counted to determine the amount of the target element present. Major applications have been determination of total O, N or Si in solid and liquid matrices, but the technique can also be applied to determine concentrations of about 30 other elements including F, Cl, Al, P and Mg. Detection limits are a few micrograms in the best cases and milligrams for most others. The method has advantages of being nondestructive, fast and insensitive to sample inhomogeneities. It lends itself especially well to sequential analysis of the same sample by several techniques and to samples that are difficult to dissolve. Portable generators have been applied to industrial situations and to well logging. Major disadvantages are the necessity to house a radiation producing instrument, the cost of the equipment and the lack of useful neutron reactions for some important elements. Accuracy (typically +-7 to 10% relative) and precision (+-1 to 5% relative) are comparable to competing techniques. For determination of low levels of O and N in most metals inert gas fusion is more rapid and sensitive; elemental analyzer is more sensitive for O and N in organics. Wet chemical methods rarely have any advantage over 14 MeV NAA for solid samples when concentrations are in the detection limit range of the 14 MeV NAA methods. Future developments in the field will come in the areas of simpler, more portable and higher neutron output generator designs. 66 refs

Transgenic plants that exhibit enhanced nitrogen assimilation

Science.gov (United States)

Coruzzi, Gloria M.; Brears, Timothy

1999-01-01

The present invention relates to a method for producing plants with improved agronomic and nutritional traits. Such traits include enhanced nitrogen assimilatory and utilization capacities, faster and more vigorous growth, greater vegetative and reproductive yields, and enriched or altered nitrogen content in vegetative and reproductive parts. More particularly, the invention relates to the engineering of plants modified to have altered expression of key enzymes in the nitrogen assimilation and utilization pathways. In one embodiment of the present invention, the desired altered expression is accomplished by engineering the plant for ectopic overexpression of one of more the native or modified nitrogen assimilatory enzymes. The invention also has a number of other embodiments, all of which are disclosed herein.

Phosphorus and nitrogen in the eutrophication of waters

International Nuclear Information System (INIS)

Salonen, S.; Frisk, T.; Kaermeniemi, T.; Niemi, J.; Pitkaenen, H.; Silvo, K.; Vuoristo, H.

1992-01-01

This report is a summary of the contribution of nitrogen and phosphorus in the eutrophication process of inland and coastal waters. Special attention was paid to the mechanisms of these nutrients in regulating biological processes and to the methods available in estimating their effects in the eutrophication of water bodies. The report includes five chapters which are entitled: Introduction, which is a general background to the subject with special attention to the requirements of the Finnish Water Act. Phosphorus and nitrogen as factors regulating biological processes. The topics included are: definition of eutrophication, forms of phosphorus and nitrogen and their sources to inland and coastal waters, effects of these nutrients as growth factors of phytoplankton and macrophytes and consequences of eutrophication. Estimation of the effects of phosphorus and nitrogen. The topics discussed from the point of view of the tasks of the National Board of Waters and the Environment are: estimation of the effects of phosphorus and nitrogen in the planning and supervision of industry, fish farming, peat production, municipalities, agriculture and forestry. A brief state-of-the art of the research carried out in the National Board of Waters and the Environment is given. Methods of estimating the effects of phosphorus and nitrogen loading in waters. The topics are: relationships between phosphorus and nitrogen concentrations in waters, material balances, water quality models, classification of waters and different groups of organisms as indicators of water quality. Conclusions for the estimation of the effects of phosphorus and nitrogen in receiving waters

Liquid absorbent solutions for separating nitrogen from natural gas

Science.gov (United States)

Friesen, Dwayne T.; Babcock, Walter C.; Edlund, David J.; Lyon, David K.; Miller, Warren K.

2000-01-01

Nitrogen-absorbing and -desorbing compositions, novel ligands and transition metal complexes, and methods of using the same, which are useful for the selective separation of nitrogen from other gases, especially natural gas.

Nitrogen Oxygen Recharge System for the International Space Station

Science.gov (United States)

Williams, David E.; Dick, Brandon; Cook, Tony; Leonard, Dan

2009-01-01

The International Space Station (ISS) requires stores of Oxygen (O2) and Nitrogen (N2) to provide for atmosphere replenishment, direct crew member usage, and payload operations. Currently, supplies of N2/O2 are maintained by transfer from the Space Shuttle. Following Space Shuttle is retirement in 2010, an alternate means of resupplying N2/O2 to the ISS is needed. The National Aeronautics and Space Administration (NASA) has determined that the optimal method of supplying the ISS with O2/N2 is using tanks of high pressure N2/O2 carried to the station by a cargo vehicle capable of docking with the ISS. This paper will outline the architecture of the system selected by NASA and will discuss some of the design challenges associated with this use of high pressure oxygen and nitrogen in the human spaceflight environment.

Implications of selection in common bean lines in contrasting environments concerning nitrogen levels

Directory of Open Access Journals (Sweden)

Isabela Volpi Furtini

2014-10-01

Full Text Available Grain productivities of 100 bean lines were evaluated in the presence and absence of nitrogen fertilizer in order to identify those with high nitrogen use efficiency (NUE and to determine the correlated response observed in a stressed environment following selection in a non-stressed environment. The genetic and phenotypic characteristics of the lines, as well as the response index to applied nitrogen, were determined. The average grain productivities at both locations were 39.5% higher in the presence of nitrogen fertilizer, with 8.3 kg of grain being produced per kg of nitrogen applied. NUE varied greatly between lines. Lines BP-16, CVII-85-11, BP-24, Ouro Negro and MA-IV-15-203 were the most efficient and responsive. The results showed that it is possible to select bean lines in stressed and non-stressed environments. It was inferred that common bean lines for environments with low nitrogen availability should preferably be selected under nitrogen stress.

Analysis of nitrogen species in titanium oxynitride ALD films

Energy Technology Data Exchange (ETDEWEB)

Sowińska, Małgorzata, E-mail: Malgorzata.Sowinska@b-tu.de [Brandenburgische Technische Universität Cottbus-Senftenberg, Angewandte Physik-Sensorik, Konrad-Wachsmann-Allee 17, 03046 Cottbus (Germany); Brizzi, Simone; Das, Chittaranjan [Brandenburgische Technische Universität Cottbus-Senftenberg, Angewandte Physik-Sensorik, Konrad-Wachsmann-Allee 17, 03046 Cottbus (Germany); Kärkkänen, Irina; Schneidewind, Jessica; Naumann, Franziska; Gargouri, Hassan [SENTECH Instruments GmbH, Schwarzschildstraße 2, 12489 Berlin (Germany); Henkel, Karsten; Schmeißer, Dieter [Brandenburgische Technische Universität Cottbus-Senftenberg, Angewandte Physik-Sensorik, Konrad-Wachsmann-Allee 17, 03046 Cottbus (Germany)

2016-09-15

Titanium oxynitride films are prepared by plasma enhanced atomic layer deposition method using two different precursors and nitrogen sources. Synchrotron radiation-based X-ray photoelectron spectroscopy and X-ray absorption spectroscopy are used to characterize the nitrogen species incorporated within these films depending on the deposition parameters. It is found that nitrogen atoms in these films are differently bonded. In particular, it can be distinguished between Ti−ON and Ti−N bonding configurations and molecular nitrogen species caused by precursor fragments.

The determination of nitrogen in zirconium by charged-particle activation analysis

International Nuclear Information System (INIS)

Strijckmans, K.; Mortier, R.; Vandecasteele, C.; Hoste, J.

1982-01-01

The determination of nitrogen in zirconium by charged-particle activation analysis is described. The 14 N(α, αn) 13 N and the 14 N(p, α) 11 C reactions were used. The 13 N activity was separated from matrix activity as ammonia by steam-distillation after dissolution of the sample in dilute hydrofluoric acid.The 11 C activity was separated as carbon dioxide by dissolution of the sample in a mixture of concentrated sulphuric acid, sodium fluoride and potassium periodate, followed by oxidation of the evolved gases with a copper oxide-iron oxide-kaolin mixture and trapping of the carbon dioxide in dilute sodium hydroxide solution. The chemical yield of both separations was investigated. The nuclear interference of boron can be neglected, in view of the low boron content. Alpha- and protonactivation yielded the following results for BCR reference materials (alpha-activation results first): CRM 21: 24.6 +- 3.3 and 25.9 +- 0.8 μg/g (certified value: 26.4 +- 2.5 μg/g);CRM 56: 12.0 +- 1.1 and 10.5 +- 0.3 μg/g (certified value: 11.7 +- 1.7 μg/g); CRM 57: 11.2 +- 0.3 μg/g (alpha/activation) (certified value: 11.9 +- 1.8 μg/g). (Author)

Evaluation of the Effect of Split application of Urea on Nitrogen Losses in Furrow Fertigation

Directory of Open Access Journals (Sweden)

farid feizolahpour

2017-01-01

Full Text Available Introduction: Broadcast fertilization method increases fertilizer losses while results in lower nutrient absorption by plant roots. Fertigation is an effective method to increase water and fertilizer efficiency and to reduce the losses of nitrogen. Moreover, it allows farmers to apply the nutrients in splits and few amounts in response to crop needs. In the present study, a field experiment was conducted to investigate the effects of split application of fertilizer in furrow fertigation on nitrogen losses and corn yield. Materials and Methods: Field experiments were carried out factorially in a randomized complete block design with four replicates. Experimental treatments were consisted of three fertilizer splits (two, three, and four splits and three levels of urea fertilizer (60, 80 and 100% of required urea fertilizer, which compared with the common method (broadcasting fertilizer as used by farmers in the fields. Experiments were conducted on a one hectare field in 120 meter long and open end furrows. During the crop season, Irrigation water was applied in the same way for all fertigation treatments and the third type of the WSC flumes was used to measure the amount of input and output water in irrigation events. Moreover, for determining the indexes of uniformity of water distribution in carrying out fertigation experiments, the amount of infiltration into the soil was calculated using the Kostiakov-Louis equation. The parameters of this equation were determined using the water volume balance method. Injection of Urea fertilizer was done by using 40-liter barrels were placed at the beginning of Furrows. In this study, the injection of fertilizers was applied in the last 10 to 20 minutes of irrigation time. Results and Discussions: Results showed that water distribution uniformities of low quarter and low half in all tests were very high. Such that the water low quarter distribution uniformities for all treatments were between 90.5 to 98

Nitrogen-15 recovery fraction in flooded tropical rice as affected by Added Nitrogen Interaction

International Nuclear Information System (INIS)

Schnier, H.F.

1994-01-01

The application of N fertilizer has been shown to cause an apparent increase in the uptake of native soil N via an effect termed ‘Added nitrogen interaction’ (ANI). This ANI caused by pool-substitution, can affect the 'IN-recovery fraction (NRF) by plants as calculated by the isotope-dilution method. The ANI effect was studied in a field experiment with transplanted and direct seeded flooded rice, comparing three methods of N-application (broadcast and incorporation of prilled urea ; band placement of urea solution ; and point placement of urea supergranules). ANI's for broadcast and incorporation treatments were generally greater than those for band and point placement treatments. The values for NRF calculated by the isotope-dilution method were lower than those of the apparent N-recovery fracton (ARF) as calculated by the difference method. Most of the discrepancy between plant nitrogen recoveries estimated by the isotope-dilution and the difference method could be explained by fertilizer losses and by pool-substitution, which means that fertilizer N stands proxy for soil N. (author)

Recent Nitrogen Deposition In Poland Monitored With The Moss Pleurozium Schreberi

Directory of Open Access Journals (Sweden)

Kapusta Paweł

2014-07-01

Full Text Available In this study, atmospheric deposition of nitrogen was determined for Poland by moss biomonitoring. Nitrogen content was measured in the moss Pleurozium schreberi (Willd. ex Brid. Mitt. sampled in 2010 from 320 sites evenly distributed throughout the country. Mosses (green parts contained an average 1.56% nitrogen. The result places Poland among the European countries most polluted by airborne nitrogen. The highest nitrogen concentrations were found in mosses from the central and southern parts of the country, and the lowest in samples from some eastern and northern regions. Multiple regression showed that this variability was due mostly to nitrogen emissions from agricultural and industrial areas (moss nitrogen was positively associated with the consumption of mineral nitrogen fertilizers and the magnitude of particulate pollution. Some details of the spatial variability of the nitrogen data indicate that local and regional point sources of pollution (e.g., chemical plants played an important role in shaping the nitrogen deposition pattern

Clinoptilolite zeolite influence on nitrogen in a manure-amended sandy agricultural soil

Science.gov (United States)

Development of best management practices can help improve inorganic nitrogen (N) availability to plants and reduce nitrate-nitrogen (NO3-N) leaching in soils. This study was conducted to determine the influence of the zeolite mineral clinoptilolite (CL) additions on NO3-N and ammonium-nitrogen (NH4-...

Nitrogen transformations in stratified aquatic microbial ecosystems

DEFF Research Database (Denmark)

Revsbech, Niels Peter; Risgaard-Petersen, N.; Schramm, Andreas

2006-01-01

Abstract  New analytical methods such as advanced molecular techniques and microsensors have resulted in new insights about how nitrogen transformations in stratified microbial systems such as sediments and biofilms are regulated at a µm-mm scale. A large and ever-expanding knowledge base about n...... performing dissimilatory reduction of nitrate to ammonium have given new dimensions to the understanding of nitrogen cycling in nature, and the occurrence of these organisms and processes in stratified microbial communities will be described in detail.......Abstract  New analytical methods such as advanced molecular techniques and microsensors have resulted in new insights about how nitrogen transformations in stratified microbial systems such as sediments and biofilms are regulated at a µm-mm scale. A large and ever-expanding knowledge base about...... nitrogen fixation, nitrification, denitrification, and dissimilatory reduction of nitrate to ammonium, and about the microorganisms performing the processes, has been produced by use of these techniques. During the last decade the discovery of anammmox bacteria and migrating, nitrate accumulating bacteria...

SPECTROPHOTOMETRIC DETERMINATION OF NITRITE BY ITS ...

African Journals Online (AJOL)

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sources of nitrite include intensive use of chemical nitrogenous fertilizers, ... The current paper describes another kinetic spectrophotometric method for determination of ... s at λmax = 570 nm (allowing a lag time of 5 s) against water as reference. ... samples and the total amount of the analyte was estimated by applying the ...

Comparison of sampling methods for animal manure

NARCIS (Netherlands)

Derikx, P.J.L.; Ogink, N.W.M.; Hoeksma, P.

1997-01-01

Currently available and recently developed sampling methods for slurry and solid manure were tested for bias and reproducibility in the determination of total phosphorus and nitrogen content of samples. Sampling methods were based on techniques in which samples were taken either during loading from

Determination of nitrogen in wheat flour through Activation analysis using Fast neutron flux of a Thermal nuclear reactor; Determinacion de nitrogeno en harina de trigo mediante analisis por activacion empleando el flujo de neutrones rapidos de un reactor nuclear termico

Energy Technology Data Exchange (ETDEWEB)

Ramirez G, T

1976-07-01

In this work is done a technical study for determining Nitrogen (protein) and other elements in wheat flour Activation analysis, with Fast neutrons from a Thermal nuclear reactor. Initially it is given an introduction about the basic principles of the methods of analysis. Equipment used in Activation analysis and a brief description of the neutron source (Thermal nuclear reactor). The realized experiments for determining the flux form in the irradiation site, the half life of N-13 and the interferences due to the sample composition are included too. Finally, the obtained results by Activation and the Kjeldahl method are tabulated. (Author)

A meta-analysis of leaf nitrogen distribution within plant canopies

NARCIS (Netherlands)

Hikosaka, Kouki; Anten, Niels P.R.; Borjigidai, Almaz; Kamiyama, Chiho; Sakai, Hidemitsu; Hasegawa, Toshihiro; Oikawa, Shimpei; Iio, Atsuhiro; Watanabe, Makoto; Koike, Takayoshi; Nishina, Kazuya; Ito, Akihiko

2016-01-01

Background and aims Leaf nitrogen distribution in the plant canopy is an important determinant for canopy photosynthesis. Although the gradient of leaf nitrogen is formed along light gradients in the canopy, its quantitative variations among species and environmental responses remain unknown.

Calculation of the vibrational linewidth and line shape of Raman spectra using the relaxation function : I. method and application to nitrogen

NARCIS (Netherlands)

Kooi, M.E.; Smit, F.; Michels, J.P.J.; Schouten, J.A.

2000-01-01

The spectral line shape of the fundamental vibration of nitrogen is calculated from molecular dynamics simulations by determining the Fourier transform of the relaxation function. It has been applied to the fluid phase at various pressures and temperatures, and to solid d-N2. The validity of the

Nitrogen availability for nitrogen fixing cyanobacteria upon growth ...

African Journals Online (AJOL)

The filamentous cyanobacterium Nostoc PCC 7120 is able to convert dinitrogen to ammonia in the absence of combined nitrogen. The expression of 20% of coding sequences from all major metabolic categories was examined in nitrogen fixing and non-nitrogen fixing growth conditions. The expression data were correlated ...

Hierarchically structured, nitrogen-doped carbon membranes

KAUST Repository

Wang, Hong; Wu, Tao

2017-01-01

The present invention is a structure, method of making and method of use for a novel macroscopic hierarchically structured, nitrogen-doped, nano-porous carbon membrane (HNDCMs) with asymmetric and hierarchical pore architecture that can be produced

Spectrophotometric Methods for the Determination of Ketoconazole ...

African Journals Online (AJOL)

Spectrophotometric Methods for the Determination of Ketoconazole in Pharmaceutical Dosage Forms. ... Tropical Journal of Pharmaceutical Research ... Methods: The first method (A) was based on the oxidation of the studied drug by a known excess of cerium (IV) as an oxidizing agent and subsequent determination of ...

Experimental identification of nitrogen-vacancy complexes in nitrogen implanted silicon

Science.gov (United States)

Adam, Lahir Shaik; Law, Mark E.; Szpala, Stanislaw; Simpson, P. J.; Lawther, Derek; Dokumaci, Omer; Hegde, Suri

2001-07-01

Nitrogen implantation is commonly used in multigate oxide thickness processing for mixed signal complementary metal-oxide-semiconductor and System on a Chip technologies. Current experiments and diffusion models indicate that upon annealing, implanted nitrogen diffuses towards the surface. The mechanism proposed for nitrogen diffusion is the formation of nitrogen-vacancy complexes in silicon, as indicated by ab initio studies by J. S. Nelson, P. A. Schultz, and A. F. Wright [Appl. Phys. Lett. 73, 247 (1998)]. However, to date, there does not exist any experimental evidence of nitrogen-vacancy formation in silicon. This letter provides experimental evidence through positron annihilation spectroscopy that nitrogen-vacancy complexes indeed form in nitrogen implanted silicon, and compares the experimental results to the ab initio studies, providing qualitative support for the same.

Nitrogen nutrition effects on development, growth and nitrogen accumulation of vegetables

NARCIS (Netherlands)

Biemond, H.

1995-01-01

In order to be able to match nitrogen supply and nitrogen requirement of vegetable crops, insight is necessary in the responses to nitrogen of important processes of growth and development. This study focused on effects of amount of nitrogen applied and fractionation of nitrogen supply on

Fertilizer nitrogen fixation in plants and its transmutation in soils in case of annual application

International Nuclear Information System (INIS)

Shilova, E.I.; Smirnov, P.M.; Khon, N.I.

1974-01-01

Using certain combinations of 15 N labeled and unlabeled nitrogen-containing fertilizers data were obtained for direct determination of nitrogen balance in the year of fertilization and subsequently. Annual and total (for 3 years) increment in utilization of soil nitrogen resulting from repeated fertilization was also determined. Coefficient of nitrogen utilization by barley decreased over the 3-year period after additional application of ammonium sulfate while biological immobilization of nitrogen tended to increase. Application of straw during the first year of the experiment did not significantly affect the nitrogen balance in the following years. The total coefficient of nitrogen utilization for the 2 to 3-year period was higher than that of the first year while biological immobilization was relatively lower. Additional utilization of soil nitrogen as compared to the control was the same over the whole 3-year period; additional mobilization (annual and total) was relatively higher due to lower removal of soil nitrogen in the subsequent years. Utilization of previously immobilized nitrogen was higher in the case of repeated fertilization than without application of nitrogen fertilizers. The content of newly immobilized nitrogen during 3 years in the hydrolyzable undistilable fraction (nitrogen of bounded amino acids) was relatively lower and this was accompanied by the growth of hydrolyzable distilable and unhydrolyzable nitrogen

Using nitrogen concentration and isotopic composition in lichens to spatially assess the relative contribution of atmospheric nitrogen sources in complex landscapes

International Nuclear Information System (INIS)

Pinho, P.; Barros, C.; Augusto, S.; Pereira, M.J.

2017-01-01

Reactive nitrogen (Nr) is an important driver of global change, causing alterations in ecosystem biodiversity and functionality. Environmental assessments require monitoring the emission and deposition of both the amount and types of Nr. This is especially important in heterogeneous landscapes, as different land-cover types emit particular forms of Nr to the atmosphere, which can impact ecosystems distinctively. Such assessments require high spatial resolution maps that also integrate temporal variations, and can only be feasibly achieved by using ecological indicators. Our aim was to rank land-cover types according to the amount and form of emitted atmospheric Nr in a complex landscape with multiple sources of N. To do so, we measured and mapped nitrogen concentration and isotopic composition in lichen thalli, which we then related to land-cover data. Results suggested that, at the landscape scale, intensive agriculture and urban areas were the most important sources of Nr to the atmosphere. Additionally, the ocean greatly influences Nr in land, by providing air with low Nr concentration and a unique isotopic composition. These results have important consequences for managing air pollution at the regional level, as they provide critical information for modeling Nr emission and deposition across regional as well as continental scales. - Highlights: • Which land-cover types are reactive nitrogen sources or sinks at a landscape level? • Nitrogen concentration and isotopic composition were analyzed in lichens. • This allowed determination of the main nitrogen sources: agricultural and urban areas. • Marine sources provided persistent low concentrations of reactive nitrogen. • The typical signature of each source was also determined. - Reactive-nitrogen concentration and isotopic composition in lichens were used to rank Nr sources at a landscape level.

The Effect of Percentage of Nitrogen in Plasma Gas on Nitrogen ...

African Journals Online (AJOL)

Increase in nitrogen percent in the plasma gas results in increased content of dissociated nitrogen and molecular nitrogen possessing excess vibrational energy and therefore the increased solution of nitrogen in the liquid iron. It would appear that above 35% nitrogen in the plasma gas, frequency of collisions of species in ...

Preparation of nitrogen-doped carbon tubes

Science.gov (United States)

Chung, Hoon Taek; Zelenay, Piotr

2015-12-22

A method for synthesizing nitrogen-doped carbon tubes involves preparing a solution of cyanamide and a suitable transition metal-containing salt in a solvent, evaporating the solvent to form a solid, and pyrolyzing the solid under an inert atmosphere under conditions suitable for the production of nitrogen-doped carbon tubes from the solid. Pyrolyzing for a shorter period of time followed by rapid cooling resulted in a tubes with a narrower average diameter.

Stable nitrogen isotopes in coastal macroalgae: Geographic and anthropogenic variability

Energy Technology Data Exchange (ETDEWEB)

Viana, Inés G., E-mail: ines.gonzalez@co.ieo.es; Bode, Antonio

2013-01-15

Growing human population adds to the natural nitrogen loads to coastal waters. Both anthropogenic and natural nitrogen is readily incorporated in new biomass, and these different nitrogen sources may be traced by the measurement of the ratio of stable nitrogen isotopes (δ{sup 15}N). In this study δ{sup 15}N was determined in two species of macroalgae (Ascophyllum nodosum and Fucus vesiculosus), and in nitrate and ammonium to determine the relative importance of anthropogenic versus natural sources of nitrogen along the coast of NW Spain. Both algal species and nitrogen sources showed similar isotopic enrichment for a given site, but algal δ{sup 15}N was not related to either inorganic nitrogen concentrations or δ{sup 15}N in the water samples. The latter suggests that inorganic nitrogen inputs are variable and do not always leave an isotopic trace in macroalgae. However, a significant linear decrease in macroalgal δ{sup 15}N along the coast is consistent with the differential effect of upwelling. Besides this geographic variability, the influence of anthropogenic nitrogen sources is evidenced by higher δ{sup 15}N in macroalgae from rias and estuaries compared to those from open coastal areas and in areas with more than 15 × 10{sup 3} inhabitants in the watershed. These results indicate that, in contrast with other studies, macroalgal δ{sup 15}N is not simply related to either inorganic nitrogen concentrations or human population size but depends on other factors as the upwelling or the efficiency of local waste treatment systems. - Highlights: ► Anthropogenic versus upwelling nitrogen effect on macroalgal δ{sup 15}N was studied. ► The influence of populations and upwelling has not been made before on macroalgal δ{sup 15}N. ► Natural variability has not been taken into account in most biomonitoring studies. ► Upwelling explains most of the variability in δ{sup 15}N in macroalgae.

Replaceable liquid nitrogen piping

International Nuclear Information System (INIS)

Yasujima, Yasuo; Sato, Kiyoshi; Sato, Masataka; Hongo, Toshio

1982-01-01

This liquid nitrogen piping with total length of about 50 m was made and installed to supply the liquid nitrogen for heat insulating shield to three superconducting magnets for deflection and large super-conducting magnet for detection in the π-meson beam line used for high energy physics experiment in the National Laboratory for High Energy Physics. The points considered in the design and manufacture stages are reported. In order to minimize the consumption of liquid nitrogen during transport, vacuum heat insulation method was adopted. The construction period and cost were reduced by the standardization of the components, the improvement of welding works and the elimination of ineffective works. For simplifying the maintenance, spare parts are always prepared. The construction and the procedure of assembling of the liquid nitrogen piping are described. The piping is of double-walled construction, and its low temperature part was made of SUS 316L. The super-insulation by aluminum vacuum evaporation and active carbon were attached on the external surface of the internal pipe. The final leak test and the heating degassing were performed. The tests on evacuation, transport capacity and heat entry are reported. By making the internal pipe into smaller size, the piping may be more efficient. (Kako, I.)

Nitrogen concentrations and loads for the Connecticut River at Middle Haddam, Connecticut, computed with the use of autosampling and continuous measurements of water quality for water years 2009 to 2014

Science.gov (United States)

Mullaney, John R.; Martin, Joseph W.; Morrison, Jonathan

2018-03-20

The daily and annual loads of nitrate plus nitrite and total nitrogen for the Connecticut River at Middle Haddam, Connecticut, were determined for water years 2009 to 2014. The analysis was done with a combination of methods, which included a predefined rating curve method for nitrate plus nitrite and total nitrogen for water years 2009 to 2011 and a custom rating curve method that included sensor measurements of nitrate plus nitrite nitrogen concentration and turbidity along with mean daily flow to determine total nitrogen loads for water years 2011 to 2014. Instantaneous concentrations of total nitrogen were estimated through the use of a regression model based on sensor measurements at 15-minute intervals of nitrate plus nitrite nitrogen and turbidity for water years 2011 to 2014.Annual total nitrogen loads at the Connecticut River at Middle Haddam ranged from 12,900 to 19,200 metric tons, of which about 42 to 49 percent was in the form of nitrate plus nitrite. The mean 95-percent prediction intervals on daily total nitrogen load estimates were smaller from the custom model, which used sensor data, than those calculated by the predefined model.Annual total nitrogen load estimates at the Connecticut River at Middle Haddam were compared with the upstream load estimates at the Connecticut River at Thompsonville, Conn. Annual gains in total nitrogen loads between the two stations ranged from 3,430 to 6,660 metric tons. These increases between the two stations were attributed to the effects of increased urbanization and to combined annual discharges of 1,540 to 2,090 metric tons of nitrogen from 24 wastewater treatment facilities in the drainage area between the two stations. The contribution of total nitrogen from wastewater discharge between the two stations had declined substantially before the beginning of this study and accounted for from 31 to 52 percent of the gain in nitrogen load between the Thompsonville and Middle Haddam sites.

Nitrogen dioxide exposures inside ice skating rinks.

Science.gov (United States)

Brauer, M; Spengler, J D

1994-01-01

OBJECTIVES. The common operation of fuel-powered resurfacing equipment in enclosed ice skating rinks has the potential for producing high concentrations of carbon monoxide and nitrogen dioxide. Exposures to these gaseous combustion products may adversely affect the health of those inside the rink. Little information is available on pollutant concentrations under normal operating conditions. METHODS. One-week average nitrogen dioxide concentrations in 70 northeastern US rinks were measured with passive samplers during normal winter season conditions. RESULTS. The median nitrogen dioxide level inside rinks was 180 ppb, more than 10 times higher than the median outdoor concentration. One-week average nitrogen dioxide concentrations above 1000 ppb were measured in 10% of the rinks. CONCLUSIONS. Considering that short-term peak concentrations were likely to have reached two to five times the measured 1-week averages, our results suggest that nitrogen dioxide levels were well above short-term air quality guidelines and constitute a public health concern of considerable magnitude. PMID:8129060

Nitrogen metabolism in the ruminant

International Nuclear Information System (INIS)

Buttery, P.J.; Lewis, D.

1976-01-01

Selected aspects of nitrogen metabolism in the ruminant are discussed. Particular attention is paid to the effect of rumen ammonia concentration on protein synthesis in the rumen. In order to judge the suitability of microbial protein as a source of protein for the ruminant, it is necessary to be able to assess the amino-acid requirements of the ruminant accurately. Several methods of doing this are discussed. Available data would indicate that under many conditions methionine is the first limiting amino acid. Possible ways of increasing the supply of methionine at the duodenum are discussed. When the amino-acid requirements are fully met, it is to be expected that protein synthesis in the tissues will proceed at its maximal rate. Ways of determining the extent of tissue protein synthesis in vivo are briefly discussed. (author)

The investigation of the n-#betta#-radiolysis of nitrogen tetroxide under super-critical conditions

International Nuclear Information System (INIS)

Nesterenko, V.B.; Gvozdev, A.A.; Doroshkevich, V.N.; Nichipor, G.V.; Trubnikov, V.P.

1983-01-01

The yield of the 'irreversible' products of nitrogen tetroxide radiolysis has been determined in stainless steel ampoules in the field of the reactor mixed radiation; Radiolysis has been investigated in the range of temperatures 200 to 350 deg C, pressures 7.8 to 15.7 MPa and dose rates 48 and 162 W/kg. The measured primary yield of nitrogen atoms under nitrogen dioxide radiolysis is equal to 0.28 + 0.02 at/100 eV at 250 deg C. It is shown that in the investigated range of temperatures and pressures the yield of the 'irreversible' radiolysis products can be determined using the known kinetic data on the reactions of nitrogen atoms with molecules and assuming the primary yield of nitrogen atoms from nitrogen dioxide and nitric oxide equal to 0.28 and 4.5 at/100 eV respectively. (author)

(15)N in tree rings as a bio-indicator of changing nitrogen cycling in tropical forests: an evaluation at three sites using two sampling methods.

Science.gov (United States)

van der Sleen, Peter; Vlam, Mart; Groenendijk, Peter; Anten, Niels P R; Bongers, Frans; Bunyavejchewin, Sarayudh; Hietz, Peter; Pons, Thijs L; Zuidema, Pieter A

2015-01-01

Anthropogenic nitrogen deposition is currently causing a more than twofold increase of reactive nitrogen input over large areas in the tropics. Elevated (15)N abundance (δ(15)N) in the growth rings of some tropical trees has been hypothesized to reflect an increased leaching of (15)N-depleted nitrate from the soil, following anthropogenic nitrogen deposition over the last decades. To find further evidence for altered nitrogen cycling in tropical forests, we measured long-term δ(15)N values in trees from Bolivia, Cameroon, and Thailand. We used two different sampling methods. In the first, wood samples were taken in a conventional way: from the pith to the bark across the stem of 28 large trees (the "radial" method). In the second, δ(15)N values were compared across a fixed diameter (the "fixed-diameter" method). We sampled 400 trees that differed widely in size, but measured δ(15)N in the stem around the same diameter (20 cm dbh) in all trees. As a result, the growth rings formed around this diameter differed in age and allowed a comparison of δ(15)N values over time with an explicit control for potential size-effects on δ(15)N values. We found a significant increase of tree-ring δ(15)N across the stem radius of large trees from Bolivia and Cameroon, but no change in tree-ring δ(15)N values over time was found in any of the study sites when controlling for tree size. This suggests that radial trends of δ(15)N values within trees reflect tree ontogeny (size development). However, for the trees from Cameroon and Thailand, a low statistical power in the fixed-diameter method prevents to conclude this with high certainty. For the trees from Bolivia, statistical power in the fixed-diameter method was high, showing that the temporal trend in tree-ring δ(15)N values in the radial method is primarily caused by tree ontogeny and unlikely by a change in nitrogen cycling. We therefore stress to account for tree size before tree-ring δ(15)N values can be properly

15N in tree rings as a bio-indicator of changing nitrogen cycling in tropical forests: an evaluation at three sites using two sampling methods

Directory of Open Access Journals (Sweden)

Peter evan der Sleen

2015-04-01

Full Text Available Anthropogenic nitrogen deposition is currently causing a more than twofold increase of reactive nitrogen input over large areas in the tropics. Elevated 15N abundance (δ15N in the growth rings of some tropical trees has been hypothesized to reflect an increased leaching of 15N-depleted nitrate from the soil following anthropogenic nitrogen deposition over the last decades. To find further evidence for altered nitrogen cycling in tropical forests we measured long-term δ15N values in trees from Bolivia, Cameroon and Thailand. We used two different sampling methods. In the first, wood samples were taken in a conventional way: from the pit to the bark across the stem of 28 large trees (the ‘radial’ method. In the second, δ15N values were compared across a fixed diameter (the ‘fixed-diameter’ method. We sampled 400 trees that differed widely in size, but measured δ15N in the stem around the same diameter (20 cm dbh in all trees. As a result, the growth rings formed around this diameter differed in age and allowed a comparison of δ15N values over time with an explicit control for the potential size-effects on δ15N values. We found a significant increase of tree-ring δ15N across the stem radius of large trees from Bolivia and Cameroon, but no change in tree-ring δ15N values over time was found in any of the study sites when controlling for tree size. This suggests that radial trends of δ15N values within trees reflect tree ontogeny (size development. However, for the trees from Cameroon and Thailand, a low statistical power in the fixed-diameter method prevents to conclude this with high certainty. For the trees from Bolivia, statistical power in the fixed-diameter method was high, showing that the temporal trend in tree-ring δ15N values in the radial method is primarily caused by tree ontogeny and unlikely by a change in nitrogen cycling. We therefore stress to account for tree size before tree-ring δ15N values can be properly

Toward a mechanistic modeling of nitrogen limitation for photosynthesis

Science.gov (United States)

Xu, C.; Fisher, R. A.; Travis, B. J.; Wilson, C. J.; McDowell, N. G.

2011-12-01

The nitrogen limitation is an important regulator for vegetation growth and global carbon cycle. Most current ecosystem process models simulate nitrogen effects on photosynthesis based on a prescribed relationship between leaf nitrogen and photosynthesis; however, there is a large amount of variability in this relationship with different light, temperature, nitrogen availability and CO2 conditions, which can affect the reliability of photosynthesis prediction under future climate conditions. To account for the variability in nitrogen-photosynthesis relationship under different environmental conditions, in this study, we developed a mechanistic model of nitrogen limitation for photosynthesis based on nitrogen trade-offs among light absorption, electron transport, carboxylization and carbon sink. Our model shows that strategies of nitrogen storage allocation as determined by tradeoff among growth and persistence is a key factor contributing to the variability in relationship between leaf nitrogen and photosynthesis. Nitrogen fertilization substantially increases the proportion of nitrogen in storage for coniferous trees but much less for deciduous trees, suggesting that coniferous trees allocate more nitrogen toward persistence compared to deciduous trees. The CO2 fertilization will cause lower nitrogen allocation for carboxylization but higher nitrogen allocation for storage, which leads to a weaker relationship between leaf nitrogen and maximum photosynthesis rate. Lower radiation will cause higher nitrogen allocation for light absorption and electron transport but less nitrogen allocation for carboxylyzation and storage, which also leads to weaker relationship between leaf nitrogen and maximum photosynthesis rate. At the same time, lower growing temperature will cause higher nitrogen allocation for carboxylyzation but lower allocation for light absorption, electron transport and storage, which leads to a stronger relationship between leaf nitrogen and maximum

The determination of nitrogen dioxide in ambient air with free hanging filters as passive samplers, and a new calibration method using fritted bubblers

NARCIS (Netherlands)

Heeres, P.; Setiawan, R.; Krol, M.C.; Adema, E.H.

2009-01-01

This paper describes two new methods for the determination of NO2 in the ambient air. The first method consists of free hanging filters with a diameter of 2.5 cm as passive samplers. The filters are impregnated with triethanolamine to bind NO2. With standard colorimetrical analysis, the amount of

Clinoptilolite zeolite influence on inorganic nitrogen in silt loam and sandy agricultural soils

Science.gov (United States)

Development of best management practices can help improve inorganic nitrogen (N) availability to plants and reduce nitrate-nitrogen (NO3-N) leaching in soils. This study was conducted to determine the influence of the zeolite mineral Clinoptilolite (CL) additions on NO3-N and ammonium-nitrogen (NH4...

Efficiency of nitrogen fertilizer in rice culture production

International Nuclear Information System (INIS)

Romero, M.R.; Perez, C.; Sosa, J.L.

1990-01-01

Using the isotopic tracer technique with 15 urea, the efficiency of three ways of nitrogen fertilizer splitting in rice was determined. Fractioning at three moments, initial tilloring, active tile ring and primordial change, allowed a better assimilation of nitrogen by the grain and the rest of the plant. The optimum moment for the application of the fertilizer was at primordial change, while the highest took place at seeding

Use of 15N methodology to assess biological nitrogen fixation

International Nuclear Information System (INIS)

Hardarson, G.

1990-01-01

One of the most important characteristics of legumes are their ability in symbiosis with Rhizobium bacteria to fix atmospheric nitrogen for growth. For proper management and a full realization of the benefits of this plant-microbial association, it is necessary to estimate how much nitrogen is fixed under different conditions in the field. It is only after this is known that various factors can be manipulated so as to increase the amount and proportion of N a plant derives from biological fixation. A suitable method for accurately measuring the amount of N crops derive from fixation is therefore an important requirement in any programme aimed at maximizing biological nitrogen fixation. There are several methods available to measure N 2 fixation (Bergersen, 1980) based on (1) increment in N yield and plant growth, (2) nitrogen balance (3) acetylene reduction and (4) the use of isotopes of N. Only isotopic methods will be illustrated here. 20 refs, 2 figs, 9 tabs

Effect of Nitrogen Foliar Application on Canola Yield (Brassica napus L. and Nitrogen Efficiency across Different Sowing Dates

Directory of Open Access Journals (Sweden)

S Doori

2016-12-01

Full Text Available Introduction Between oil seeds, from the quality, quantity and nutrition index point of view, canola has the top level . Because of the solubility of N fertilizers, the time of urea application, is very important and one of the main reasons of the reduction in N application efficiency is utilization of urea in an inappropriate time. By precisely foliar application of nitrogen, the efficiency of nitrogen transformation to the grain will be very high because in this method the leaf is considered the main organ of nitrogen uptake and a low amount of absorbed nitrogen was transferred to the root and entered the soil. The more division of N application in growth stages and in accordance with plant need and foliar application result in increasing nitrogen use efficiency. The delay in sowing will result in the reduction of yield and this is due to low LAI, and thus low radiation absorb in vegetable phase and shorter reproductive phase with high temperature in flowering and subsequent stages that result in low prolific silique and make disorder in transferring stored material to grain. In this experiment using N foliar application to decrease the adverse effect of delay in sowing is objective. Materials and Methods The experiment was conducted in 2013-2014 in Ramin Agriculture and Natural Resource University of Khuzestan. Experiment was conducted as split plots in a randomized complete blocks design with three replications. In this experiment sowing date]optimum sowing (27 November, 17 December and late sowing (30 December [were assigned to main plots and several time of N-foliar application with 5 percent density from urea (20 liter per ha, ]TO (control, T1 (foliar N application in rosette stage, T2 (foliar N application in budding stage, T3 (foliar N application in flowering stage[ were placed in sub-plots in randomized way. Fertilizing was based on the results of soil examination. Therefore, 162 kg ha-1 of pure nitrogen (from resource urea in the way

Nitrogen-doping effects on the growth, structure and electrical performance of carbon nanotubes obtained by spray pyrolysis method

Energy Technology Data Exchange (ETDEWEB)

Ionescu, Mihnea Ioan; Zhang Yong; Li Ruying [Department of Mechanical and Materials Engineering, University of Western Ontario, London, ON N6A 5B9 (Canada); Abou-Rachid, Hakima [Defense Research and Development Canada - Valcartier, 2459 Boulevard PieXI Nord, Quebec, QC G3J 1X5 (Canada); Sun Xueliang, E-mail: xsun@eng.uwo.ca [Department of Mechanical and Materials Engineering, University of Western Ontario, London, ON N6A 5B9 (Canada)

2012-03-01

Vertically aligned nitrogen-doped carbon nanotubes (CNTs) with modulated nitrogen content have been synthesized in a large scale by using spray pyrolysis chemical vapor deposition technique. The effects of nitrogen doping on the growth, structure and electrical performance of carbon nanotubes have been systematically examined. Field emission scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and Raman techniques have been employed to characterize the morphology, composition, and vibrational properties of nanotubes. The results indicate that the nitrogen incorporation significantly influences the growth rate, morphology, size and structure of nanotubes. Electrical measurement investigation of the nanotubes indicates that the change in electrical resistance increases with temperature and pressure as the nitrogen concentration increases inside the tubes. This work presents a versatile, safe, and easy way to scale up route of growing carbon nanotubes with controlled nitrogen content and modulated structure, and may provide an insight in developing various nitrogen-doped carbon-based nanodevices.

The 14N(d,0)15N nuclear reaction method for nitrogen depth distribution measurements in wheat and barley

International Nuclear Information System (INIS)

Goenczi, L.; Didriksson, R.; Berggren, H.; Sundqvist, B.; Lindh, U.; Awal, M.A.

1980-01-01

The 14 N(d,p 0 ) 15 N reaction has been used to measure nitrogen depth distributions in single grains of wheat and barley. With the beam energy used (6 MeV) a depth of 225 μm was reached. In order to test the applicability of the method for plant breeding purposes we have studied 1000 grains of wheat and grains of barley, which are part of a larger material of about 50 000 grains grown and harvested under controlled biological conditions. The measured nitrogen distributions in wheat show striking correlations with parameters describing the nitrogen level of fertilizer, the time of harvesting, the grain position in a head and the analyzed variety of wheat. Contributions to the spectra from silicon in the hull of barley are demonstrated. Contributions from interfering elements in the aleuron layer in wheat placed a limit of 120 μm to the depth region analyzed. The importance of effects like pileup, heating of the grains by the beam and grain asymmetries were studied in detail. The possibility to use the technique for selection purposes in plant breeding will be discussed. (author)

Deposition of inorganic particulate aerosols to vegetation - a new method of estimating

International Nuclear Information System (INIS)

Kwiecien, M.

1997-01-01

A new, direct method was developed for quantifying inorganic particulate aerosols trapped by the forest canopy, and for determining the resulting input of elements to a forest ecosystem. The method is based on direct measurements of only six parameters. Using this method, it is possible to determine the load of aerosols trapped by the forest canopy and deposited to leaves, as well as the load of aerosols falling to the forest floor by impaction on plants. It is also possible to estimate the aerosol input of soluble and insoluble elements to an ecosystem. With this new method it was found that the load of aerosols trapped by the canopy of a mixed forest locate din the Rybnik Coal Basin averaged 189.0 kg x ha -1 x growing season or 39.3% of the total inorganic particles reaching the ecosystem. The trapped aerosols provided 13.4 kg x ha -1 of soluble nitrogen and 0.91 kg x ha -1 of insoluble nitrogen over the growing season. At the same time, the input of soluble nitrogen from the atmosphere with rainfall to an open area averaged 13.9 kg x ha -1 , and the input of insoluble nitrogen with inorganic dusts averaged 1.4. kg x ha -1

Thermal and chemical durability of nitrogen-doped carbon nanotubes

International Nuclear Information System (INIS)

Liu Hao; Zhang Yong; Li Ruying; Sun Xueliang; Abou-Rachid, Hakima

2012-01-01

Nitrogen-doped carbon nanotubes (CN x tubes) with nitrogen content of 7.6 at.% are synthesized on carbon papers. Thermal and chemical stability of the nanotubes are investigated by thermogravimetric analysis, differential scanning calorimetry and X-ray photoelectron spectroscopy techniques. The results indicate that the nitrogen can be firmly kept in the nanotubes after annealing at 300 °C in air. Under an argon atmosphere, the nitrogen would not release until 670 °C, and half of the nitrogen incorporated is released after annealing at 700 °C for 30 min. Chemical stability investigation indicates that the nitrogen incorporated in the nanotubes is very stable under the thermal and acid environment comparable to working condition of proton exchange membrane (PEM) fuel cells. Profile of the nitrogen species inside the nanotubes reveals that graphite-like nitrogen releases slower than any other kind of nitrogen in the nanotubes during the chemical stability measurement. These CN x tubes synthesized by this simple chemical vapor deposition method are expected to be suitable for many applications, such as PEM fuel cells that work under both thermal and corrosive conditions and some other mild thermal environments.

Zirconium determination in refractories (gravimetric method)

International Nuclear Information System (INIS)

Capiotto, N.; Narahashi, Y.; Perish, C.G.; Souza, J.R.

1991-01-01

The zirconium determination in refractories is described, consisting in two separation methods for eliminating the interferences. The formatted product is calcined at 1100 0 C and determined gravimetrically as Zr P z 07. (author)

Effect of nitrogen doping on the thermal conductivity of GeTe thin films

Energy Technology Data Exchange (ETDEWEB)

Fallica, Roberto; Longo, Massimo; Wiemer, Claudia [Laboratorio MDM, IMM-CNR, Agrate Brianza (Italy); Varesi, Enrico; Fumagalli, Luca; Spadoni, Simona [Micron Semiconductor Italia, Agrate Brianza (Italy)

2013-12-15

The 3{omega} method was employed to determine the effect of nitrogen doping (5 at.%) on the thermal conductivity of sputtered thin films of stoichiometric GeTe (a material of interest for phase change memories). It was found that nitrogen doping has a detrimental effect on the thermal conductivity of GeTe in both phases, but less markedly in the amorphous (-25%) than in the crystalline one (-40%). On the opposite, no effect could be detected on the measured thermal boundary resistance between these films and SiO{sub 2}, within the experimental error. Our results agree with those obtained by molecular dynamic simulation of amorphous GeTe. (copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Cycle length and COD/N ratio determine properties of aerobic granules treating high-nitrogen wastewater.

Science.gov (United States)

Cydzik-Kwiatkowska, Agnieszka; Bernat, Katarzyna; Zielińska, Magdalena; Wojnowska-Baryła, Irena

2014-07-01

Aerobic granule characteristic in sequencing batch reactors treating high-nitrogen digester supernatant was investigated at cycle lengths (t) of 6, 8 and 12 h with the COD/N ratios in the influent of 4.5 and 2.3. The biomass production (Y obs) correlated with the extracellular polymeric substances (EPS) in grams per COD removed. Denitrification efficiency significantly decreased as the amount of EPS in biomass increased, suggesting that organic assimilation in EPS hampers nitrogen removal. Granule hydrophobicity was highest at t of 8 h; the t has to be long enough to remove pollutants, but not so long that excessive biomass starvation causes extracellular protein consumption that decreases hydrophobicity. At a given t, reducing the COD/N ratio improved hydrophobicity that stimulates cell aggregation. At t of 6 h and the COD/N ratio of 2.3, the dominance of 0.5-1.0 mm granules favored simultaneous nitrification and denitrification and resulted in the highest nitrogen removal.

Validation of nitrogen-nitrate analysis by the chromotropic acid method

Energy Technology Data Exchange (ETDEWEB)

Santos, Ana Claudia O.; Matoso, Erika, E-mail: anaclaudia.oliveira@marinha.mil.br [Centro Tecnológico da Marinha em São Paulo (CTMSP/CEA), Iperó, SP (Brazil). Centro Experimental ARAMAR

2017-07-01

The problems caused by contamination of water bodies demand strict control of disposal in rivers, seas and oceans. Nitrate ion is present in agricultural inputs, which are applied to the soil to boost plant growth. However, excess or indiscriminate use of these products contaminates water bodies, triggering eutrophication of the aquatic ecosystems. Furthermore, due to diseases that can be caused by the ingestion of high levels of nitrate, such as methaemoglobinaemia, nitrate levels should be controlled in drinking waters and effluents. There are several methods for the determination of nitrate, being the chromotropic acid method a simple and low-cost solution. This method consists of acid addition into the sample in the presence of H{sub 2}SO{sub 4}. The absorbance related to the produced yellow color can be measured by a UV-Vis spectrophotometer at 410 nm. In a modified form, this method can be applied to different aqueous matrices by use of other reagents that eliminate interferences. The aim of this study was to validate the nitrate determination method in waters using chromotropic acid. This method is used in Laboratório Radioecológico (LARE) to analyze effluent to comply with Wastewater Controlling Program of Centro Tecnológico da Marinha em São Paulo – Centro Experimental ARAMAR (CTMSP-CEA). The correlation coefficient for the linearity test was 0.9997. The evaluated detection limit was relatively high (LD = 0.045 mgN/L), if compared to ion chromatography, for example, but enough to determine the presence of this ion, considering the maximum limit proposed by the current legislation. The chromotropic acid method showed to be a robust, accurate and precise method, according the parameters used in this work. (author)

Validation of nitrogen-nitrate analysis by the chromotropic acid method

International Nuclear Information System (INIS)

Santos, Ana Claudia O.; Matoso, Erika

2017-01-01

The problems caused by contamination of water bodies demand strict control of disposal in rivers, seas and oceans. Nitrate ion is present in agricultural inputs, which are applied to the soil to boost plant growth. However, excess or indiscriminate use of these products contaminates water bodies, triggering eutrophication of the aquatic ecosystems. Furthermore, due to diseases that can be caused by the ingestion of high levels of nitrate, such as methaemoglobinaemia, nitrate levels should be controlled in drinking waters and effluents. There are several methods for the determination of nitrate, being the chromotropic acid method a simple and low-cost solution. This method consists of acid addition into the sample in the presence of H 2 SO 4 . The absorbance related to the produced yellow color can be measured by a UV-Vis spectrophotometer at 410 nm. In a modified form, this method can be applied to different aqueous matrices by use of other reagents that eliminate interferences. The aim of this study was to validate the nitrate determination method in waters using chromotropic acid. This method is used in Laboratório Radioecológico (LARE) to analyze effluent to comply with Wastewater Controlling Program of Centro Tecnológico da Marinha em São Paulo – Centro Experimental ARAMAR (CTMSP-CEA). The correlation coefficient for the linearity test was 0.9997. The evaluated detection limit was relatively high (LD = 0.045 mgN/L), if compared to ion chromatography, for example, but enough to determine the presence of this ion, considering the maximum limit proposed by the current legislation. The chromotropic acid method showed to be a robust, accurate and precise method, according the parameters used in this work. (author)

Econometric Analysis of Effects of Nitrogenous Fertilizer Usage on Tomato Yield in Tokat, Turkey

Directory of Open Access Journals (Sweden)

Bilge Gözener

2017-04-01

Full Text Available This study aims to investigate the effects of nitrogen fertilizer application on tomato yield by using econometric models. The data obtained by questionnaire from 53 farmers who produce tomatoes in Tokat province constitute the main material of the study. The Simple Random Sampling Method was used to determine the sample size with a 90% confidence interval and 10% margin of error. Nine models were tried to determine the best model to explain the effect of nitrogenous fertilizer usage in tomato cultivation. The data in the models were used to calculate the growers’ optimal fertilizer amount of use (physical optimum and economical optimum values were calculated and the results were compared to the ones suggested by the experts. As a result, through the statistical studies, quadratic model was found to be the most suitable one. It has been determined that tomato farmers use less (10.54 kg da-1 or excess (23.48 kg da-1 N fertilizer than the level at which economic optimum is achieved.

Energy transfers between N_2(A"3Σ) nitrogen metastable molecules and oxygen atoms and molecules

International Nuclear Information System (INIS)

De Souza, Antonio Rogerio

1985-01-01

This research thesis aims at determining reaction coefficients for energy transfers between nitrogen in its metastable status and oxygen atoms and molecules, the variation of these coefficients with respect to temperature (mainly in the 200-400 K range), products formed and more particularly branching rates of O("1S) oxygen and of NO_2. Reaction coefficients are experimentally determined by using the technique of post-discharge in flow. The experimental set-up is described and the study of the best operating conditions is reported. In the next part, the author reports the study of the energy transfer between nitrogen in its metastable status N_2(A) and oxygen molecules. Reaction coefficients are determined for the first three vibrational levels. The author then reports the study of the transfer of N_2(A) molecules on oxygen atoms in their fundamental status. Reactions coefficients and their variations are determined for the three first vibrational levels. The author describes the dissociation method and the method of detection of atomic oxygen. A kinetic model is proposed for the analysis of formed products during a post-discharge in flow, and the branching rate for the formation of O("1S) oxygen between 190 and 365 K is determined. The author finally discusses publications on the role of these reactions in the interpretation of some atmospheric phenomena