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Sample records for nitrogen fluorescence emissions

  1. Nitrogen fluorescence in air for observing extensive air showers

    CERN Document Server

    Keilhauer, B; Fraga, M; Matthews, J; Sakaki, N; Tameda, Y; Tsunesada, Y; Ulrich, A

    2012-01-01

    Extensive air showers initiate the fluorescence emissions from nitrogen molecules in air. The UV-light is emitted isotropically and can be used for observing the longitudinal development of extensive air showers in the atmosphere over tenth of kilometers. This measurement technique is well-established since it is exploited for many decades by several cosmic ray experiments. However, a fundamental aspect of the air shower analyses is the description of the fluorescence emission in dependence on varying atmospheric conditions. Different fluorescence yields affect directly the energy scaling of air shower reconstruction. In order to explore the various details of the nitrogen fluorescence emission in air, a few experimental groups have been performing dedicated measurements over the last decade. Most of the measurements are now finished. These experimental groups have been discussing their techniques and results in a series of \\emph{Air Fluorescence Workshops} commenced in 2002. At the 8$^{\\rm{th}}$ Air Fluoresc...

  2. One-pot and ultrafast synthesis of nitrogen and phosphorus co-doped carbon dots possessing bright dual wavelength fluorescence emission

    Science.gov (United States)

    Sun, Xiangcheng; Brückner, Christian; Lei, Yu

    2015-10-01

    Very brief microwave heating of aniline, ethylene diamine, and phosphoric acid in water at ambient pressure generated nitrogen and phosphorus co-doped carbon dots (N,P-CDs) that exhibit bright dual blue (centred at 450 nm; 51% quantum yield) and green (centred at 510 nm, 38% quantum yield) fluorescence emission bands. The N,P-CDs were characterized using TEM, XRD, XPS, IR, UV-vis, and fluorescence spectroscopy, demonstrating their partially crystalline carbon, partially amorphous structures, and the incorporation of O, N, and P into the carbogenic scaffold. The N,P-CDs demonstrated excitation-dependent and nearly pH-independent emission properties. The unique dual emission properties lay the foundation for the use of N,P-CDs in ratiometric sensing applications.Very brief microwave heating of aniline, ethylene diamine, and phosphoric acid in water at ambient pressure generated nitrogen and phosphorus co-doped carbon dots (N,P-CDs) that exhibit bright dual blue (centred at 450 nm; 51% quantum yield) and green (centred at 510 nm, 38% quantum yield) fluorescence emission bands. The N,P-CDs were characterized using TEM, XRD, XPS, IR, UV-vis, and fluorescence spectroscopy, demonstrating their partially crystalline carbon, partially amorphous structures, and the incorporation of O, N, and P into the carbogenic scaffold. The N,P-CDs demonstrated excitation-dependent and nearly pH-independent emission properties. The unique dual emission properties lay the foundation for the use of N,P-CDs in ratiometric sensing applications. Electronic supplementary information (ESI) available: Detailed experimental section, XRD, FTIR, explosive sensing and the applications results. See DOI: 10.1039/c5nr05549k

  3. Effect of carbon and nitrogen assimilation on chlorophyll fluorescence emission by the cyanobacterium Anacystis nidulans

    Energy Technology Data Exchange (ETDEWEB)

    Romero, J.M.; Lara, C. (Instituto de Bioquimica Vegetal y Fotosintesis, Univ. de Sevilla y CSIC, Sevilla (ES)); Sivak, M.N. (Dept. of Biochemistry, Michigan State Univ., East Lansing (US))

    1992-01-01

    O{sub 2} evolution and chlorophyll A fluorescence emission have been monitored in intact cells of the cyanobacterium Anacystis nidulans 1402-1 to study the influence of carbon and nitrogen assimilation on the operation of the photosynthetic apparatus. The pattern of fluorescence induction in dark-adapted cyanobacterial cells was different from that of higher plants. Cyanobacteria undergo large, rapid state transitions upon illumination, which lead to marked changes in the fluorescence yield, complicating the estimation of quenching coefficients. The Kautsky effect was not evident, although it could be masked by a state II-state I transition, upon illumination with actinic light. The use of inhibitors of carbon assimilation such as D,L-glyceraldehyde or iodoacetamide allowed us to relate changes in variable fluorescence to active CO{sub 2} fixation. Ammonium, but not nitrate, induced non-photochemical fluorescence quenching, in agreement with a previous report on green algae, indicative of an ammonium-induced state i transition. (au).

  4. Graphitic Nitrogen Triggers Red Fluorescence in Carbon Dots.

    Science.gov (United States)

    Holá, Kateřina; Sudolská, Mária; Kalytchuk, Sergii; Nachtigallová, Dana; Rogach, Andrey L; Otyepka, Michal; Zbořil, Radek

    2017-12-26

    Carbon dots (CDs) are a stable and highly biocompatible fluorescent material offering great application potential in cell labeling, optical imaging, LED diodes, and optoelectronic technologies. Because their emission wavelengths provide the best tissue penetration, red-emitting CDs are of particular interest for applications in biomedical technologies. Current synthetic strategies enabling red-shifted emission include increasing the CD particle size (sp 2 domain) by a proper synthetic strategy and tuning the surface chemistry of CDs with suitable functional groups (e.g., carboxyl). Here we present an elegant route for preparing full-color CDs with well-controllable fluorescence at blue, green, yellow, or red wavelengths. The two-step procedure involves the synthesis of a full-color-emitting mixture of CDs from citric acid and urea in formamide followed by separation of the individual fluorescent fractions by column chromatography based on differences in CD charge. Red-emitting CDs, which had the most negative charge, were separated as the last fraction. The trend in the separation, surface charge, and red-shift of photoluminescence was caused by increasing amount of graphitic nitrogen in the CD structure, as was clearly proved by XPS, FT-IR, Raman spectroscopy, and DFT calculations. Importantly, graphitic nitrogen generates midgap states within the HOMO-LUMO gap of the undoped systems, resulting in significantly red-shifted light absorption that in turn gives rise to fluorescence at the low-energy end of the visible spectrum. The presented findings identify graphitic nitrogen as another crucial factor that can red-shift the CD photoluminescence.

  5. Foliar Reflectance and Fluorescence Responses for Corn and Soybean Plants Under Nitrogen Stress

    Science.gov (United States)

    Middleton, E. M.; Campbell, P. K. Entcheva; Corp, L. A.; Butcher, L. M.; McMurtrey, J. E.

    2003-01-01

    We are investigating the use of spectral indices derived from actively induced fluorescence spectra and passive optical spectra. We examined the influence of photosynthetic pigment, carbon (C) and nitrogen (N) content on the spectral fluorescence and passive optical property characteristics of mature, upper leaves from plants provided different N fertilizer application rates: 20%, 50%, 100% and 150% of recommended N levels. A suite of optical, fluorescence, and biophysical measurements were collected on leaves from field grown corn (Zea mays L.) and soybean plants (Glycine max L.) grown in pots (greenhouse + ambient sunlight. Steady state laser-induced fluorescence emission spectra (5 nm resolution) were obtained from adaxial and abaxial surfaces resulting from excitation at single wavelengths (280, 380 or 360, and 532 nm). For emission spectra produced by each of these excitation wavelengths, ratios of emission peaks were calculated, including the red far-red chlorophyll fluorescence (ChlF) ratio (F685/F740) and the far-red/green (F740/F525) ratio. High resolution (treatment groups was possible with specific fluorescence band ratios (e.g., F740/F525 obtained with 380 nm excitation). Higher ChlF and blue-green emissions were measured from the abaxial leaf surfaces. Abaxial surfaces also produced higher reflectances, in general, in the 400-800 nm spectrum.

  6. Quenching of the OH and nitrogen molecular emission by methane addition in an Ar capacitively coupled plasma to remove spectral interference in lead determination by atomic fluorescence spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Frentiu, T., E-mail: ftibi@chem.ubbcluj.r [Faculty of Chemistry and Chemical Engineering, Babes-Bolyai University, Arany Janos 11, 400028 Cluj-Napoca (Romania); Ponta, M., E-mail: mponta@chem.ubbcluj.r [Faculty of Chemistry and Chemical Engineering, Babes-Bolyai University, Arany Janos 11, 400028 Cluj-Napoca (Romania); Mihaltan, A.I., E-mail: alinblaj2005@yahoo.co [National Institute for Research and Development of Optoelectronics Bucharest - Research Institute for Analytical Instrumentation, Donath 67, 400293 Cluj-Napoca (Romania); Darvasi, E., E-mail: edarvasi@chem.ubbcluj.r [Faculty of Chemistry and Chemical Engineering, Babes-Bolyai University, Arany Janos 11, 400028 Cluj-Napoca (Romania); Frentiu, M., E-mail: frentiu.maria@yahoo.co [National Institute for Research and Development of Optoelectronics Bucharest - Research Institute for Analytical Instrumentation, Donath 67, 400293 Cluj-Napoca (Romania); Cordos, E., E-mail: emilcordos@gmail.co [National Institute for Research and Development of Optoelectronics Bucharest - Research Institute for Analytical Instrumentation, Donath 67, 400293 Cluj-Napoca (Romania)

    2010-07-15

    A new method is proposed to remove the spectral interference on elements in atomic fluorescence spectrometry by quenching of the molecular emission of the OH radical (A{sup 2{Sigma}+} {yields} X{sup 2{Pi}}) and N{sub 2} second positive system (C{sup 3{Pi}}{sub u} {yields} B{sup 3{Sigma}}{sub g}) in the background spectrum of medium power Ar plasmas. The experiments were carried out in a radiofrequency capacitively coupled plasma (275 W, 27.12 MHz) by CH{sub 4} addition. The quenching is the result of the high affinity of OH radical for a hydrogen atom from the CH{sub 4} molecule and the collisions of the second kind between nitrogen excited molecules and CH{sub 4}, respectively. The decrease of the emission of N{sub 2} second positive system in the presence of CH{sub 4} is also the result of the deactivation of the metastable argon atoms that could excite the nitrogen molecules. For flow rates of 0.7 l min{sup -1} Ar with addition of 7.5 ml min{sup -1} CH{sub 4}, the molecular emission of OH and N{sub 2} was completely removed from the plasma jet spectrum at viewing heights above 60 mm. The molecular emission associated to CH and CH{sub 2} species was not observed in the emission spectrum of Ar/CH{sub 4} plasma in the ultraviolet range. The method was experimented for the determination of Pb at 283.31 nm by atomic fluorescence spectrometry with electrodeless discharge lamp and a multichannel microspectrometer. The detection limit was 35 ng ml{sup -1}, 2-3 times better than in atomic emission spectrometry using the same plasma source, and similar to that in hollow cathode lamp microwave plasma torch atomic fluorescence spectrometry.

  7. Excitation-emission spectra and fluorescence quantum yields for fresh and aged biogenic secondary organic aerosols

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hyun Ji; Laskin, Alexander; Laskin, Julia; Nizkorodov, Sergey A.

    2013-05-10

    Certain biogenic secondary organic aerosols (SOA) become absorbent and fluorescent when exposed to reduced nitrogen compounds such as ammonia, amines and their salts. Fluorescent SOA may potentially be mistaken for biological particles by detection methods relying on fluorescence. This work quantifies the spectral distribution and effective quantum yields of fluorescence of SOA generated from two monoterpenes, limonene and a-pinene, and two different oxidants, ozone (O3) and hydroxyl radical (OH). The SOA was generated in a smog chamber, collected on substrates, and aged by exposure to ~100 ppb ammonia vapor in air saturated with water vapor. Absorption and excitation-emission matrix (EEM) spectra of aqueous extracts of aged and control SOA samples were measured, and the effective absorption coefficients and fluorescence quantum yields (~0.005 for 349 nm excitation) were determined from the data. The strongest fluorescence for the limonene-derived SOA was observed for excitation = 420+- 50 nm and emission = 475 +- 38 nm. The window of the strongest fluorescence shifted to excitation = 320 +- 25 nm and emission = 425 +- 38 nm for the a-pinene-derived SOA. Both regions overlap with the excitation-emission matrix (EEM) spectra of some of the fluorophores found in primary biological aerosols. Our study suggests that, despite the low quantum yield, the aged SOA particles should have sufficient fluorescence intensities to interfere with the fluorescence detection of common bioaerosols.

  8. The role of secondary electrons in some experiments determining fluorescence emission from nitrogen C3Πu levels

    International Nuclear Information System (INIS)

    Blanco, F.; Arqueros, F.

    2005-01-01

    The processes involved in fluorescence emission from C 3 Π u levels of N 2 molecule by electron impact are studied. Secondary electrons are shown to play an important role in typical experiments for the measurement of emission cross sections and fluorescence yields, dominating at high impact energies. A simple model is proposed which accounts for fluorescence measurements in a wide range of experimental conditions, and in particular for some recent results up to 1 GeV energies

  9. Foliar Reflectance and Fluorescence Responses for Corn and Soybean Plants Under Nitrogen Stress

    Science.gov (United States)

    Middleton, E. M.; Campbell, P. K. Entcheva; Corp, L. A.; Butcher, L. M.; McMurtrey, J. E.

    2003-01-01

    We are investigating the use of spectral indices derived from actively induced fluorescence spectra and passive optical spectra. We examined the influence of photosynthetic pigment, carbon (C) and nitrogen (N) content on the spectral fluorescence and passive optical property characteristics of mature, upper leaves from plants provided different N fertilizer application rates: 20%, 50%, 100% and 150% of recommended N levels. A suite of optical, fluorescence, and biophysical measurements were collected on leaves from field grown corn (Zea mays L.) and soybean plants (Glycine max L.) grown in pots (greenhouse + ambient sunlight. Steady state laser-induced fluorescence emission spectra (5 nm resolution) were obtained from adaxial and abaxial surfaces resulting from excitation at single wavelengths (280, 380 or 360, and 532 nm). For emission spectra produced by each of these excitation wavelengths, ratios of emission peaks were calculated, including the red far-red chlorophyll fluorescence (ChlF) ratio (F685/F740) and the far-red/green (F740/F525) ratio. High resolution (< 3 nm) optical spectra (350-2500 nm) of reflectance, transmittance, and absorptance were also acquired for both adaxial and abaxial leaf surfaces. Species differences were demonstrated for several optical parameters. A 'red edge' derivative ratio determined from transmittance spectra [as the maximum first deivative, between 650-750 nm, normalized to the value at 744 nm, or Dmax/D744], was strongly associated with the C/N ratio (r(exp 2) = 0.90, P +/- 0.001). This ratio, calculated from reflectance spectra, was inversely related to chlorophyll b content (r(exp 2) = 0.91, P +/- 0.001) as was the ChlF (F685/F740) ratio obtained with 532 nm excitation (r(exp 2) = 0.76, P +/- 0.01). Discrimination of N treatment groups was possible with specific fluorescence band ratios (e.g., F740/F525 obtained with 380 nm excitation). Higher ChlF and blue-green emissions were measured from the abaxial leaf surfaces

  10. Optimal Fluorescence Waveband Determination for Detecting Defective Cherry Tomatoes Using a Fluorescence Excitation-Emission Matrix

    Directory of Open Access Journals (Sweden)

    In-Suck Baek

    2014-11-01

    Full Text Available A multi-spectral fluorescence imaging technique was used to detect defective cherry tomatoes. The fluorescence excitation and emission matrix was used to measure for defects, sound surface and stem areas to determine the optimal fluorescence excitation and emission wavelengths for discrimination. Two-way ANOVA revealed the optimal excitation wavelength for detecting defect areas was 410 nm. Principal component analysis (PCA was applied to the fluorescence emission spectra of all regions at 410 nm excitation to determine the emission wavelengths for defect detection. The major emission wavelengths were 688 nm and 506 nm for the detection. Fluorescence images combined with the determined emission wavebands demonstrated the feasibility of detecting defective cherry tomatoes with >98% accuracy. Multi-spectral fluorescence imaging has potential utility in non-destructive quality sorting of cherry tomatoes.

  11. Metal-enhanced fluorescence exciplex emission.

    Science.gov (United States)

    Zhang, Yongxia; Mali, Buddha L; Geddes, Chris D

    2012-01-01

    In this letter, we report the first observation of metal-enhanced exciplex fluorescence, observed from anthracene in the presence of diethylaniline. Anthracene in the presence of diethylaniline in close proximity to Silver Island Films (SIFs) shows enhanced monomer and exciplex emission as compared to a non-silvered control sample containing no silver nanoparticles. Our findings suggest two complementary methods for the enhancement: (i) surface plasmons can radiate coupled monomer and exciplex fluorescence efficiently, and (ii) enhanced absorption (enhanced electric near-field) further facilitates enhanced emission. Our exciplex studies help us to further understand the complex photophysics of the metal-enhanced fluorescence technology. Copyright © 2011 Elsevier B.V. All rights reserved.

  12. Graphitic Nitrogen Triggers Red Fluorescence in Carbon Dots

    Czech Academy of Sciences Publication Activity Database

    Holá, K.; Sudolská, M.; Kalytchuk, S.; Nachtigallová, Dana; Rogach, A. L.; Otyepka, M.; Zbořil, R.

    2017-01-01

    Roč. 11, č. 12 (2017), s. 12402-12410 ISSN 1936-0851 R&D Projects: GA ČR(CZ) GBP208/12/G016 Institutional support: RVO:61388963 Keywords : nitrogen-doped * graphene dots * red fluorescence * fluorescence mechanism * band-gap tuning Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 13.942, year: 2016

  13. Optical Reflectance and Fluorescence for Detecting Nitrogen Needs in Zea mays L.

    Science.gov (United States)

    McMurtrey, J. E.; Middleton, E. M.; Corp. L. A.; Campbell, P. K. Entcheva; Butcher, L. M.; Daughtry, C. S. T.

    2003-01-01

    Nitrogen (N) status in field grown corn (Zea mays L.) was assessed using spectral techniques. Passive reflectance remote sensing and, both passive and active fluorescence sensing methods were investigated. Reflectance and fluorescence methods are reported to detect changes in the primary plant pigments (chlorophylls a and b; carotenoids) in higher plant species. As a general rule, foliar chlorophyll a (Chl a) and chlorophyll b (Chl b) usually exist in approx.3:l ratio. In plants under stress, Chl b content is affected before Chl a reductions occur. For reflectance, a version of the chlorophyll absorption in reflectance index (CARI) method was tested with narrow bands from the Airborne Imaging Spectroradiometer for Applications (ASIA). CARI minimizes the effects of soil background on the signal from green canopies. A modified CARI (MCARI) was used to track total Chl a levels in the red dip of the spectrum from the corn canopy. A second MCARI was used to track the auxiliary plant pigments (Chl b and the carotenoids) in the yellow/orange/red edge part of the reflectance spectrum. The difference between these two MCARI indices detected variations in N levels across the field plot canopies using ASIA data. At the leaf level, ratios of fluorescence emissions in the blue, green, red and far-red wavelengths sensed responses that were associated with the plant pigments, and were indicative of energy transfer in the photosynthetic process. N stressed corn stands could be distinguish from those with optimally applied N with fluorescence emission spectra obtained from individual corn leaves. Both reflectance and fluorescence methods are sensitive in detecting corn N needs and may be especially powerful in monitoring crop conditions if both types of information can be combined.

  14. Measuring reactive oxygen and nitrogen species with fluorescent probes: challenges and limitations

    Science.gov (United States)

    Kalyanaraman, Balaraman; Darley-Usmar, Victor; Davies, Kelvin J.A.; Dennery, Phyllis A.; Forman, Henry Jay; Grisham, Matthew B.; Mann, Giovanni E.; Moore, Kevin; Roberts, L. Jackson; Ischiropoulos, Harry

    2013-01-01

    The purpose of this position paper is to present a critical analysis of the challenges and limitations of the most widely used fluorescent probes for detecting and measuring reactive oxygen and nitrogen species. Where feasible, we have made recommendations for the use of alternate probes and appropriate analytical techniques that measure the specific products formed from the reactions between fluorescent probes and reactive oxygen and nitrogen species. We have proposed guidelines that will help present and future researchers with regard to the optimal use of selected fluorescent probes and interpretation of results. PMID:22027063

  15. Foliar Reflectance and Fluorescence Responses for Plants Under Nitrogen Stress Determined with Active and Passive Systems

    Science.gov (United States)

    Middleton, E. M.; McMurtrey, J. E.; Campbell, P. K. Entcheva; Corp, L. A.; Butcher, L. M.; Chappelle, E. W.

    2003-01-01

    Vegetation productivity is driven by nitrogen (N) availability in soils. Both excessive and low soil N induce physiological changes in plant foliage. In 2001, we examined the use of spectral fluorescence and reflectance measurements to discriminate among plants provided different N fertilizer application rates: 20%, 50%, 100% and 150% of optimal N levels. A suite of optical, fluorescence, and biophysical measurements were collected on leaves from field grown corn (Zea mays L.) and soybean plants (Glycine max L.) grown in pots (greenhouse + ambient sunlight daily). Three types of steady state laser-induced fluorescence measurements were made on adaxial and abaxial surfaces: 1) fluorescence images in four 10 nm bands (blue, green, red, far-red) resulting from broad irradiance excitation; 2) emission spectra (5 nm resolution) produced by excitation at single wavelengths (280,380 or 360, and 532 nm); and 3) excitation spectra (2 nm resolution), with emission wavelengths fixed at wavelengths centered on selected solar Fraunhofer lines (532,607,677 and 745 nm). Two complementary sets of high resolution (less than 2 nm) optical spectra were acquired for both adaxial and abaxial leaf surfaces: 1) optical properties (350-2500 nm) for reflectance, transmittance, and absorptance; and 2) reflectance spectra (500-1000 nm) acquired with and without a short pass filter at 665 nm to determine the fluorescence contribution to apparent reflectance in the 650-750 spectrum, especially at the 685 and 740 nm chlorophyll fluorescence (ChIF) peaks. The strongest relationships between foliar chemistry and optical properties were demonstrated for C/N content and two optical parameters associated with the red edge inflection point. Select optical properties and ChIF parameters were highly correlated for both species. A significant contribution of ChIF to apparent reflectance was observed, averaging 10-25% at 685 nm and 2 - 6% at 740 nm over all N treatments. Discrimination of N treatment

  16. Energy transfer in Anabaena variabilis filaments adapted to nitrogen-depleted and nitrogen-enriched conditions studied by time-resolved fluorescence.

    Science.gov (United States)

    Onishi, Aya; Aikawa, Shimpei; Kondo, Akihiko; Akimoto, Seiji

    2017-09-01

    Nitrogen is among the most important nutritious elements for photosynthetic organisms such as plants, algae, and cyanobacteria. Therefore, nitrogen depletion severely compromises the growth, development, and photosynthesis of these organisms. To preserve their integrity under nitrogen-depleted conditions, filamentous nitrogen-fixing cyanobacteria reduce atmospheric nitrogen to ammonia, and self-adapt by regulating their light-harvesting and excitation energy-transfer processes. To investigate the changes in the primary processes of photosynthesis, we measured the steady-state absorption and fluorescence spectra and time-resolved fluorescence spectra (TRFS) of whole filaments of the nitrogen-fixing cyanobacterium Anabaena variabilis at 77 K. The filaments were grown in standard and nitrogen-free media for 6 months. The TRFS were measured with a picosecond time-correlated single photon counting system. Despite the phycobilisome degradation, the energy-transfer paths within phycobilisome and from phycobilisome to both photosystems were maintained. However, the energy transfer from photosystem II to photosystem I was suppressed and a specific red chlorophyll band appeared under the nitrogen-depleted condition.

  17. [Interactions of straw, nitrogen fertilizer and bacterivorous nematodes on soil labile carbon and nitrogen and greenhouse gas emissions].

    Science.gov (United States)

    Zhang, Teng-Hao; Wang, Nan; Liu, Man-Qiang; Li, Fang-Hui; Zhu, Kang-Li; Li, Hui-Xin; Hu, Feng

    2014-11-01

    A 3 x 2 factorial design of microcosm experiment was conducted to investigate the interactive effects of straw, nitrogen fertilizer and bacterivorous nematodes on soil microbial biomass carbon (C(mic)) and nitrogen (N(mic)), dissolved organic carbon (DOC) and nitrogen (DON), mineral nitrogen (NH(4+)-N and NO(3-)-N), and greenhouse gas (CO2, N2O and CH4) emissions. Results showed that straw amendment remarkably increased the numbers of bacterivorous nematodes and the contents of Cmic and Nmic, but Cmic and Nmic decreased with the increasing dose of nitrogen fertilization. The effects of bacterivorous nematodes strongly depended on either straw or nitrogen fertilization. The interactions of straw, nitrogen fertilization and bacterivorous nematodes on soil DOC, DON and mineral nitrogen were strong. Straw and nitrogen fertilization increased DOC and mineral nitrogen contents, but their influences on DON depended on the bacterivorous nematodes. The DOC and mineral nitrogen were negatively and positively influenced by the bacterivorous nematodes, re- spectively. Straw significantly promoted CO2 and N2O emissions but inhibited CH4 emission, while interactions between nematodes and nitrogen fertilization on emissions of greenhouse gases were obvious. In the presence of straw, nematodes increased cumulative CO2 emissions with low nitrogen fertilization, but decreased CO2 and N2O emissions with high nitrogen fertilization on the 56th day after incubation. In summary, mechanical understanding the soil ecological process would inevitably needs to consider the roles of soil microfauna.

  18. Assisted Interpretation of Laser-Induced Fluorescence Spectra of Egg-Based Binding Media Using Total Emission Fluorescence Spectroscopy

    International Nuclear Information System (INIS)

    Anglos, D.; Nevin, A.

    2006-01-01

    Laser-induced fluorescence (LIF) spectroscopy can provide nondestructive, qualitative analysis of protein-based binding media found in artworks. Fluorescence emissions from proteins in egg yolk and egg white are due to auto fluorescent aromatic amino acids as well as other native and age-related fluorophores, but the potential of fluorescence spectroscopy for the differentiation between binding media is dependent on the choice of a suitable excitation wavelength and limited by problems in interpretation. However, a better understanding of emission spectra associated with LIF can be achieved following comparisons with total emission fluorescence spectra where a series of consecutive emission spectra are recorded over a specific range. Results using nanosecond UV laser sources for LIF of egg-based binding media are presented which are rationalised following comparisons with total emission spectra. Specifically, fluorescence is assigned to tryptophan and oxidation products of amino acids; in the case of egg yolk, fatty-acid polymerisation and age-related degradation products account for the formation of fluorophores.

  19. Effect of reaction temperature on structure and fluorescence properties of nitrogen-doped carbon dots

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yi [Key Laboratory of Interface Science and Engineering in Advanced Materials (Taiyuan University of Technology), Ministry of Education, Taiyuan 030024 (China); College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Department of Chemistry and Chemical Engineering, Lyuliang University, Lyuliang 033001 (China); Research Center on Advanced Materials Science and Technology, Taiyuan University of Technology, Taiyuan 030024 (China); Wang, Yaling [Key Laboratory of Interface Science and Engineering in Advanced Materials (Taiyuan University of Technology), Ministry of Education, Taiyuan 030024 (China); Research Center on Advanced Materials Science and Technology, Taiyuan University of Technology, Taiyuan 030024 (China); Feng, Xiaoting [Key Laboratory of Interface Science and Engineering in Advanced Materials (Taiyuan University of Technology), Ministry of Education, Taiyuan 030024 (China); College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Zhang, Feng [Key Laboratory of Interface Science and Engineering in Advanced Materials (Taiyuan University of Technology), Ministry of Education, Taiyuan 030024 (China); Research Center on Advanced Materials Science and Technology, Taiyuan University of Technology, Taiyuan 030024 (China); Yang, Yongzhen, E-mail: yyztyut@126.com [Key Laboratory of Interface Science and Engineering in Advanced Materials (Taiyuan University of Technology), Ministry of Education, Taiyuan 030024 (China); Research Center on Advanced Materials Science and Technology, Taiyuan University of Technology, Taiyuan 030024 (China); Liu, Xuguang, E-mail: liuxuguang@tyut.edu.cn [Key Laboratory of Interface Science and Engineering in Advanced Materials (Taiyuan University of Technology), Ministry of Education, Taiyuan 030024 (China); College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan 030024 (China)

    2016-11-30

    Highlights: • Nitrogen-doped carbon dots (NCDs) from ammonia solution and citric acid were synthesized at different temperatures. • Quantum yield (QY) of NCDs depends largely on the amount of fluorescent polymer chains (FPC), more FPC gives higher QY. • The law of QY of NCDs first increase and then decrease with the reaction temperature increased is found and explained. • Nitrogen doping plays significant role in getting increased UV–vis absorption and QY. - Abstract: To investigate the effect of reaction temperature and nitrogen doping on the structure and fluorescence properties of carbon dots (CDs), six kinds of nitrogen-doped CDs (NCDs) were synthesized at reaction temperatures of 120, 140, 160, 180, 200 and 220 °C, separately, by using citric acid as carbon source and ammonia solution as nitrogen source. Nitrogen-free CDs (N-free CDs-180) was also prepared at 180 °C by using citric acid as the only carbon source for comparison. Results show that reaction temperature has obvious effect on carbonization degree, quantum yield (QY), ultraviolet-visible (UV–vis) absorption and photoluminescence (PL) spectra but less effect on functional groups, nitrogen doping degree and fluorescence lifetime of NCDs. Compared with N-free CDs-180, NCDs-180 possesses enchanced QY and longer fluorescence lifetime. Doping nitrogen has obvious effect on UV–vis absorption and PL spectra but less effect on particles sizes and carbonization degree. The formation mechanism of NCDs is explored: QY of NCDs depends largely on the number of fluorescent polymer chains (FPC), the competition between FPC formation on the surface of NCDs and carbon core growth leads to the change in number of FPC, and consequently to the NCDs with highest QY at appropriate hydrothermal temperature.

  20. Bright and photostable nitrogen-vacancy fluorescence from unprocessed detonation nanodiamond.

    Science.gov (United States)

    Reineck, P; Capelli, M; Lau, D W M; Jeske, J; Field, M R; Ohshima, T; Greentree, A D; Gibson, B C

    2017-01-05

    Bright and photostable fluorescence from nitrogen-vacancy (NV) centers is demonstrated in unprocessed detonation nanodiamond particle aggregates. The optical properties of these particles is analyzed using confocal fluorescence microscopy and spectroscopy, time resolved fluorescence decay measurements, and optically detected magnetic resonance experiments. Two particle populations with distinct optical properties are identified and compared to high-pressure high-temperature (HPHT) fluorescent nanodiamonds. We find that the brightness of one detonation nanodiamond particle population is on the same order as that of highly processed fluorescent 100 nm HPHT nanodiamonds. Our results may open the path to a simple and up-scalable route for the production of fluorescent NV nanodiamonds for use in bioimaging applications.

  1. 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.

  2. Photoacoustic emission from fluorescent nanodiamonds enhanced with gold nanoparticles

    Science.gov (United States)

    Zhang, Bailin; Fang, Chia-Yi; Chang, Cheng-Chun; Peterson, Ralph; Maswadi, Saher; Glickman, Randolph D.; Chang, Huan-Cheng; Ye, Jing Yong

    2012-01-01

    Fluorescent nanodiamonds (FNDs) have drawn much attention in recent years for biomedical imaging applications due to their desired physical properties including excellent photostability, high biocompatibility, extended far-red fluorescence emission, and ease of surface functionalization. Here we explore a new feature of FNDs, i.e. their photoacoustic emission capability, which may lead to potential applications of using FNDs as a dual imaging contrast agent for combined fluorescence and photoacoustic imaging modalities. We observed significant enhancement of photoacoustic emission from FNDs when they were conjugated with gold nanoparticles (GNPs). PMID:22808436

  3. Photoacoustic emission from fluorescent nanodiamonds enhanced with gold nanoparticles.

    Science.gov (United States)

    Zhang, Bailin; Fang, Chia-Yi; Chang, Cheng-Chun; Peterson, Ralph; Maswadi, Saher; Glickman, Randolph D; Chang, Huan-Cheng; Ye, Jing Yong

    2012-07-01

    Fluorescent nanodiamonds (FNDs) have drawn much attention in recent years for biomedical imaging applications due to their desired physical properties including excellent photostability, high biocompatibility, extended far-red fluorescence emission, and ease of surface functionalization. Here we explore a new feature of FNDs, i.e. their photoacoustic emission capability, which may lead to potential applications of using FNDs as a dual imaging contrast agent for combined fluorescence and photoacoustic imaging modalities. We observed significant enhancement of photoacoustic emission from FNDs when they were conjugated with gold nanoparticles (GNPs).

  4. Photoacoustic emission from fluorescent nanodiamonds enhanced with gold nanoparticles

    OpenAIRE

    Zhang, Bailin; Fang, Chia-Yi; Chang, Cheng-Chun; Peterson, Ralph; Maswadi, Saher; Glickman, Randolph D.; Chang, Huan-Cheng; Ye, Jing Yong

    2012-01-01

    Fluorescent nanodiamonds (FNDs) have drawn much attention in recent years for biomedical imaging applications due to their desired physical properties including excellent photostability, high biocompatibility, extended far-red fluorescence emission, and ease of surface functionalization. Here we explore a new feature of FNDs, i.e. their photoacoustic emission capability, which may lead to potential applications of using FNDs as a dual imaging contrast agent for combined fluorescence and photo...

  5. Soil biochemical properties of grassland ecosystems under anthropogenic emission of nitrogen compounds

    Science.gov (United States)

    Kudrevatykh, Irina; Ivashchenko, Kristina; Ananyeva, Nadezhda

    2016-04-01

    Inflow of pollutants in terrestrial ecosystems nowadays increases dramatically, that might be led to disturbance of natural biogeochemical cycles and landscapes structure. Production of nitrogen fertilizers is one of the air pollution sources, namely by nitrogen compounds (NH4+, NO3-, NO2-). Air pollution by nitrogen compounds of terrestrial ecosystems might be affected on soil biochemical properties, which results increasing mineral nitrogen content in soil, changing soil P/N and Al/Ca ratios, and, finally, the deterioration of soil microbial community functioning. The research is focused on the assessment of anthropogenic emission of nitrogen compounds on soil properties of grassland ecosystems in European Russia. Soil samples (Voronic Chernozem Pachic, upper 10 cm mineral layer, totally 10) were taken from grassland ecosystem: near (5-10 m) nitrogen fertilizer factory (NFF), and far from it (20-30 km, served as a control) in Tula region. In soil samples the NH4+ and NO3- (Kudeyarov's photocolorimetric method), P, Ca, Al (X-ray fluorescence method) contents were measured. Soil microbial biomass carbon (Cmic) was analyzed by substrate-induced respiration method. Soil microbial respiration (MR) was assessed by CO2 rate production. Soil microbial metabolic quotient (qCO2) was calculated as MR/Cmic ratio. Near NFF the soil ammonium and nitrate nitrogen contents were a strongly varied, variation coefficient (CV) was 42 and 86This study was supported by Russian Foundation of Basic Research Grant No. 14-04-00098, 15-44-03220, 15-04-00915.

  6. Advances in Fluorescence Sensing Systems for the Remote Assessment of Nitrogen Supply in Field Corn

    Science.gov (United States)

    Corp, L. A.; Chappelle, E. W.; McMurtrey, J. E.; Daughtry, C. S. T.; Kim, M. S.

    2000-01-01

    The studies described herein were conducted to better define changes in fluorescence properties of leaves from field grown corn (Zea mays L.) as they relate to varying levels of nitrogen (N) fertilization. This research was directed toward: 1) providing a remote non-destructive sensing technique to aid in the determination of optimal rates of N fertilization in corn crops and, 2) defining parameters for further development of fluorescence instrumentation to be operated remotely at field canopy levels. Fluorescence imaging bands centered in the blue (450 nm), green (525 nm), red (680 nm), and far-red (740 nm) and ratios of these bands were compared with the following plant parameters: rates of photosynthesis, N:C ratio, pigment concentrations, and grain yields. Both the fluorescence and physiological measures exhibited similar curvilinear responses to N fertilization level while significant linear correlations were obtained among fluorescence bands and band ratios to certain physiological measures of plant productivity. The red / blue, red / green, far-red / blue, far-red /green fluorescence ratios are well suited for remote observation and provided high correlations to grain yield, LAI, N:C, and chlorophyll contents. The results from this investigation indicate that fluorescence technology could aid in the determination of N fertilization requirements for corn. This discussion will also address design concepts and preliminary field trials of a mobile field-based Laser Induced Fluorescence Imaging System (LIFIS) capable of simultaneously acquiring images of four fluorescence emission bands from areas of plant canopies equaling 1 sq m and greater without interference of ambient solar radiation.

  7. Cysteine detection using a high-fluorescence sensor based on a nitrogen-doped graphene quantum dot–mercury(II) system

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Zhenzhen; Gong, Yan; Fan, Zhefeng, E-mail: zhefengfan@126.com

    2016-07-15

    A novel and highly sensitive fluorescence sensor, which was based on the recovered fluorescence of a nitrogen-doped graphene quantum dot–Hg(II) system, was developed for cysteine detection. An easy, green, one-pot synthesis of nitrogen-doped graphene quantum dots was established by using citric acid and urea as carbon and nitrogen sources, respectively. The fluorescence of nitrogen-doped graphene quantum dots was significantly quenched by Hg(II) because of the efficient electron transfer between nitrogen-doped graphene quantum dots and Hg(II). Subsequently, fluorescence was recovered gradually upon cysteine addition to form a stable complex with Hg(II). The fluorescence sensor showed a response to cysteine within a wide concentration range of 0.05–30 μmol L{sup −1}, with a detection limit of 1.3 nmol L{sup −1}. The sensor was successfully applied to detect cysteine in honey and beer samples, with a recovery range of 98–105%.

  8. Cysteine detection using a high-fluorescence sensor based on a nitrogen-doped graphene quantum dot–mercury(II) system

    International Nuclear Information System (INIS)

    Liu, Zhenzhen; Gong, Yan; Fan, Zhefeng

    2016-01-01

    A novel and highly sensitive fluorescence sensor, which was based on the recovered fluorescence of a nitrogen-doped graphene quantum dot–Hg(II) system, was developed for cysteine detection. An easy, green, one-pot synthesis of nitrogen-doped graphene quantum dots was established by using citric acid and urea as carbon and nitrogen sources, respectively. The fluorescence of nitrogen-doped graphene quantum dots was significantly quenched by Hg(II) because of the efficient electron transfer between nitrogen-doped graphene quantum dots and Hg(II). Subsequently, fluorescence was recovered gradually upon cysteine addition to form a stable complex with Hg(II). The fluorescence sensor showed a response to cysteine within a wide concentration range of 0.05–30 μmol L −1 , with a detection limit of 1.3 nmol L −1 . The sensor was successfully applied to detect cysteine in honey and beer samples, with a recovery range of 98–105%.

  9. Effects of nitrogen loading on greenhouse gas emissions in salt marshes

    Science.gov (United States)

    Tang, J.; Moseman-Valtierra, S.; Kroeger, K. D.; Morkeski, K.; Mora, J.; Chen, X.; Carey, J.

    2014-12-01

    Salt marshes play an important role in global and regional carbon and nitrogen cycling. We tested the hypothesis that anthropogenic nitrogen loading alters greenhouse gas (GHG, including CO2, CH4, and N2O) emissions and carbon sequestration in salt marshes. We measured GHG emissions biweekly for two growing seasons across a nitrogen-loading gradient of four Spartina salt marshes in Waquoit Bay, Massachusetts. In addition, we conducted nitrogen addition experiments in a pristine marsh by adding low and high nitrate to triplicate plots bi-weekly during the summer. The GHG flux measurements were made in situ with a state-of-the-art mobile gas measurement system using the cavity ring down technology that consists of a CO2/CH4 analyzer (Picarro) and an N2O/CO analyzer (Los Gatos). We observed strong seasonal variations in greenhouse gas emissions. The differences in gas emissions across the nitrogen gradient were not significant, but strong pulse emissions of N2O were observed after nitrogen was artificially added to the marsh. Our results will facilitate model development to simulate GHG emissions in coastal wetlands and support methodology development to assess carbon credits in preserving and restoring coastal wetlands.

  10. Greenhouse gas emissions from nitrogen fertilizer use in China

    International Nuclear Information System (INIS)

    Kahrl, Fredrich; Li, Yunju; Su, Yufang; Tennigkeit, Timm; Wilkes, Andreas; Xu, Jianchu

    2010-01-01

    The use of synthetic nitrogen (N) fertilizers is an important driver of energy use and greenhouse gas (GHG) emissions in China. This paper develops a GHG emission factor for synthetic N fertilizer application in China. Using this emission factor, we estimate the scale of GHG emissions from synthetic nitrogen fertilizer use in Chinese agriculture and explore the potential for GHG emission reductions from efficiency improvements in N fertilizer production and use. The paper concludes with a discussion on costs and financing for a large-scale fertilizer efficiency improvement program in China, and how a GHG mitigation framework might contribute to program design.

  11. Nitrogen Oxide Emission, Economic Growth and Urbanization in China: a Spatial Econometric Analysis

    Science.gov (United States)

    Zhou, Zhimin; Zhou, Yanli; Ge, Xiangyu

    2018-01-01

    This research studies the nexus of nitrogen oxide emissions and economic development/urbanization. Under the environmental Kuznets curve (EKC) hypothesis, we apply the analysis technique of spatial panel data in the STIRPAT framework, and thus obtain the estimated impacts of income/urbanization on nitrogen oxide emission systematically. The empirical findings suggest that spatial dependence on nitrogen oxide emission distribution exist at provincial level, and the inverse N-shape EKC describes both income-nitrogen oxide and urbanization-nitrogen oxide nexuses. In addition, some well-directed policy advices are made to reduce the nitrogen oxide emission in future.

  12. Fluorescence Indices for the Proximal Sensing of Powdery Mildew, Nitrogen Supply and Water Deficit in Sugar Beet Leaves

    Directory of Open Access Journals (Sweden)

    Georg Leufen

    2014-03-01

    Full Text Available Using potted sugar beet plants we aimed to investigate the suitability of four fluorescence indices to detect and differentiate the impact of nitrogen supply, water deficit and powdery mildew in two sugar beet cultivars (Beta vulgaris L.. Plants were grown inside a polytunnel under two nitrogen levels combined with water deficit or full irrigation. Changes in plant physiology were recorded at two physiological stages with a multiparametric handheld fluorescence sensor and a fluorescence imaging system. The analysis of chlorophyll content and osmotic potential served as reference. Based on our results, the fluorescence indices “Nitrogen Balance Index” and “Simple Fluorescence Ratio” responded quite sensitively to drought stress and mildew infection. Moreover, the blue-to-far-red fluorescence ratio revealed significant stress-induced alterations in the plant physiology. In all, fluorescence indices might be used as single or combined indices for successful stress sensing. However, a robust stress differentiation by using only one fluorescence ratio could not be accomplished.

  13. Environmental consequences from emission of nitrogen oxides and ammonia

    International Nuclear Information System (INIS)

    Iverfeldt, Aa.; Pleijel, H.; Klemedtsson, L.; Loevblad, G.; Omstedt, G.

    1995-02-01

    The aim of this study have been to compare environmental problems pertaining to nitrogen containing pollutants from power generation from biomass fuels. Local effects of NO x and NH 3 in air are normally small. Emission of NO x add plant toxic ozone, which is not the case at emission of NH 3 and N 2 O. The problem is slightly greater when siting in southern Sweden. The total emission of ammonium and nitrates are of major importance for acidification and nitrogen saturation. The largest contribution to the greenhouse effect comes from direct emission of nitrous oxide. The emission of N 2 O does not influence the siting aspects of the power plant, because of the global implications of this substance. 21 refs, 9 figs, 14 tabs

  14. Volatile organic compounds and oxides of nitrogen. Further emission reductions

    Energy Technology Data Exchange (ETDEWEB)

    Froste, H [comp.

    1997-12-31

    This report presents the current status in relation to achievement of the Swedish Environmental target set by Parliament to reduce emission of volatile organic compounds by 50 per cent between 1988 and 2000. It also instructed the Agency to formulate proposed measures to achieve a 50 per cent reduction of emission of nitrogen oxides between 1985 and 2005. The report presents an overall account of emission trends for volatile organic compounds (from all sectors) and nitrogen oxides (from the industry sector) and steps proposed to achieve further emission reductions. 43 refs

  15. Volatile organic compounds and oxides of nitrogen. Further emission reductions

    Energy Technology Data Exchange (ETDEWEB)

    Froste, H. [comp.

    1996-12-31

    This report presents the current status in relation to achievement of the Swedish Environmental target set by Parliament to reduce emission of volatile organic compounds by 50 per cent between 1988 and 2000. It also instructed the Agency to formulate proposed measures to achieve a 50 per cent reduction of emission of nitrogen oxides between 1985 and 2005. The report presents an overall account of emission trends for volatile organic compounds (from all sectors) and nitrogen oxides (from the industry sector) and steps proposed to achieve further emission reductions. 43 refs

  16. Background information on a multimedia nitrogen emission reduction strategy; Hintergrundpapier zu einer multimedialen Stickstoffemissionsminderungsstrategie

    Energy Technology Data Exchange (ETDEWEB)

    Geupel; Jering; Frey (and others)

    2009-04-15

    The background information report on a multimedia nitrogen reduction strategy covers the following chapters: 1. Introduction: the nitrogen cascade and the anthropogenic influence, environmental impact of increased nitrogen emissions and effects on human health. 2. Sources and balancing of anthropogenic nitrogen emissions in Germany. 3. Environmental quality targets, activity goals of environmental measures and instruments of an integrated nitrogen reduction strategy. 4. Conclusions and perspectives. The attachments include emission sources, nitrogen release and nitrogen transport in Germany; catalogue of measures and instruments according the criteria efficiency and cost-efficacy.

  17. Legislative measures for suppressing emission of nitrogen oxides from thermal power stations

    Energy Technology Data Exchange (ETDEWEB)

    Kotler, V.R.

    1987-11-01

    Reviews measures taken by some countries to control emission of nitrogen oxides from thermal power stations run on solid fuels, mazout and gas. Refers to maximum permissible concentrations of nitrogen oxides in USA (100 mg/m/sup 3/), Canada (460 mg/m/sup 3/), Japan (41-62 mg/m/sup 3/) and several European countries. Discusses legislative measures in FRG (Federal Regulations BImSchG), particularly Instruction No. 13 BImSchV concerning large boilers run on solid fuels or mazout (continuous monitoring of nitrogen oxide emission into atmosphere, equipping old boilers with means of reducing nitrogen oxide emission, reduction of acid rain). Gives maximum permissible concentrations of nitrogen oxides for new boilers agreed by various countries. 5 refs.

  18. Experimental assessment of fluorescence microscopy signal enhancement by stimulated emission

    Science.gov (United States)

    Dake, Fumihiro; Yazawa, Hiroki

    2017-10-01

    The quantity of photons generated during fluorescence microscopy is principally determined by the quantum yield of the fluorescence dyes and the optical power of the excitation beam. However, even though low quantum yields can produce poor images, it is challenging to tune this parameter, while increasing the power of the excitation beam often results in photodamage. Here, we propose the use of stimulated emission (SE) as a means of enhancing both the signal intensity and signal-to-noise ratio during confocal fluorescence microscopy. This work experimentally confirmed that both these factors can be enhanced by SE radiation, through generating a greater number of photons than are associated with the standard fluorescence signal. We also propose the concept of stimulated emission enhancing fluorescence (SEEF) microscopy, which employs both the SE and fluorescence signals, and demonstrate that the intensity of an SEEF signal is greater than those of the individual SE and fluorescence signals.

  19. Effects of nitrogen fertilizer application on greenhouse gas emissions and economics of corn production.

    Science.gov (United States)

    Kim, Seungdo; Dale, Bruce E

    2008-08-15

    Nitrogen fertilizer plays an important role in corn cultivation in terms of both economic and environmental aspects. Nitrogen fertilizer positively affects corn yield and the soil organic carbon level, but it also has negative environmental effects through nitrogen-related emissions from soil (e.g., N20, NOx, NO3(-) leaching, etc.). Effects of nitrogen fertilizer on greenhouse gas emissions associated with corn grain are investigated via life cycle assessment. Ecoefficiency analysis is also used to determine an economically and environmentally optimal nitrogen application rate (NAR). The ecoefficiency index in this study is defined as the ratio of economic return due to nitrogen fertilizer to the greenhouse gas emissions of corn cultivation. Greenhouse gas emissions associated with corn grain decrease as NAR increases at a lower NAR until a minimum greenhouse gas emission level is reached because corn yield and soil organic carbon level increase with NAR. Further increasing NAR after a minimum greenhouse gas emission level raises greenhouse gas emissions associated with corn grain. Increased greenhouse gas emissions of corn grain due to nitrous oxide emissions from soil are much higher than reductions of greenhouse gas emissions of corn grain due to corn yield and changes in soil organic carbon levels at a higher NAR. Thus, there exists an environmentally optimal NAR in terms of greenhouse gas emissions. The trends of the ecoefficiency index are similar to those of economic return to nitrogen and greenhouse gas emissions associated with corn grain. Therefore, an appropriate NAR could enhance profitability as well as reduce greenhouse gas emissions associated with corn grain.

  20. Blue-green fluorescence and visible-infrared reflectance of corn (Zea mays L.) grain for in situ field detection of nitrogen supply

    International Nuclear Information System (INIS)

    McMurtrey, J.E. III; Chappelle, E.W.; Kim, M.S.; Corp, L.A.; Daughtry, C.S.T.

    1996-01-01

    The sensing of spectral attributes of corn (Zea mays L.) grain from site specific areas of the field during the harvest process may be useful in managing agronomic inputs and production practices on those areas of the field in subsequent growing seasons. Eight levels of nitrogen (N) fertilization were applied to field grown corn at Beltsville, Maryland. These N treatments produced a range of chlorophyll levels, biomass and physiological condition in the live plant canopies. After harvest, spectra were obtained in the laboratory on whole grain samples. Fluorescence emissions were acquired from 400 to 600 nm and percent reflectance were measured in the visible (VIS) near infrared (NIR) and mid-infrared (MIR) regions from 400 nm to 2400 nm. A ultraviolet (UV) excitation band centered at 385 nm was the most effective in producing fluorescence emission differences in the blue-green region of the fluorescence spectrum with maxima centered from 430-470nm in the blue and with an intense shoulder centered at around 530-560 nm in the green region. Reflectance showed the most spectral differences in the NIR and MIR (970-2330 nm) regions

  1. Quantifying the Global Marine Biogenic Nitrogen Oxides Emissions

    Science.gov (United States)

    Su, H.; Wang, S.; Lin, J.; Hao, N.; Poeschl, U.; Cheng, Y.

    2017-12-01

    Nitrogen oxides (NOx) are among the most important molecules in atmospheric chemistry and nitrogen cycle. The NOx over the ocean areas are traditionally believed to originate from the continental outflows or the inter-continental shipping emissions. By comparing the satellite observations (OMI) and global chemical transport model simulation (GEOS-Chem), we suggest that the underestimated modeled atmospheric NO2 columns over biogenic active ocean areas can be possibly attributed to the biogenic source. Nitrification and denitrification in the ocean water produces nitrites which can be further reduced to NO through microbiological processes. We further report global distributions of marine biogenic NO emissions. The new added emissions improve the agreement between satellite observations and model simulations over large areas. Our model simulations manifest that the marine biogenic NO emissions increase the atmospheric oxidative capacity and aerosol formation rate, providing a closer link between atmospheric chemistry and ocean microbiology.

  2. Enhanced solid state emission of quinoline derivatives for fluorescent sensors

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyong-Jun, E-mail: hkim@kongju.ac.kr

    2016-08-15

    Excited-state intramolecular proton transfer (ESIPT) molecules are of utmost interest in the fields of organic light emitting diode, photo-patterning, chemosensor, proton transfer laser, and photostabilizer. Fine control of the functional substituents as well as the molecular structure of core ESIPT unit is primarily demanded for specific applications. Here, the photophysics of quinoline derivatives of 2-quinolin-2-yl-phenol and 2-(8-chloroquinolin-2-yl)phenol is explored. Straightening the twist between the hydroxyphenyl and the quinoline moieties with the aid of the hydrogen bonding promoted the excited energy to flow through a radiative decay pathway via proton transfer to the nitrogen. Furthermore, close molecular packing of J-aggregates and thus resulted vibration restriction in a dense matter opens an ESIPT corridor and is characterized to show enhanced emission. The mechanism is applied to the selective Cu{sup 2+} or Fe{sup 2+} cation detection and further immunofluorescence labeling using avidin–biotin protein specific binding is demonstrated with the aid of nano self-assembly technique. - Highlights: • New orange fluorescent hydroxyphenylquinoline derivative was synthesized. • Molecular structure planarization induced enhanced fluorescence with large Stokes' shift. • Selective solution phase cation detection and solid state bio-sensing were demonstrated successfully.

  3. [Vermicomposting of different organic materials and three-dimensional excitation emission matrix fluorescence spectroscopic characterization of their dissolved organic matter].

    Science.gov (United States)

    Yang, Wei; Wang, Dong-sheng; Liu, Man-qiang; Hu, Feng; Li, Hui-xin; Huang, Zhong-yang; Chang, Yi-jun; Jiao, Jia-guo

    2015-10-01

    In this experiment, different proportions of the cattle manure, tea-leaf, herb and mushroom residues, were used as food for earthworm (Eisenia fetida) to study the growth of the earth-worm. Then the characteristics and transformation of nutrient content and three-dimensional excitation emission matrix fluorescence (3DEEM) of dissolved organic matter (DOM) during vermistabilization were investigated by means of chemical and spectroscopic methods. The result showed that the mixture of different ratios of cattle manure with herb residue, and cattle manure with tea-leaf were conducive to the growth of earthworm, while the materials compounded with mushroom residue inhibited the growth of earthworm. With the increasing time of verimcomposting, the pH in vermicompost tended to be circumneutral and weakly acidic, and there were increases in electrical conductivity, and the contents of total nitrogen, total phosphorus, available nitrogen, and available phosphorus, while the total potassium and available potassium increased first and then decreased, and the organic matter content decreased. 3DEEM and fluorescence regional integration results indicated that, the fluorescence of protein-like fluorescence peaks declined significantly, while the intensity of humic-like fluorescence peak increased significantly in DOM. Vermicomposting process might change the compositions of DOM with elevated concentrations of humic acid and fulvic acid in the organics. In all, this study suggested the suitability of 3DEEM for monitoring the organics transformation and assessing the maturity in the vermicomposting.

  4. Fluorescence Indices for the Proximal Sensing of Powdery Mildew, Nitrogen Supply and Water Deficit in Sugar Beet Leaves

    OpenAIRE

    Leufen, Georg; Noga, Georg; Hunsche, Mauricio

    2014-01-01

    Using potted sugar beet plants we aimed to investigate the suitability of four fluorescence indices to detect and differentiate the impact of nitrogen supply, water deficit and powdery mildew in two sugar beet cultivars (Beta vulgaris L.). Plants were grown inside a polytunnel under two nitrogen levels combined with water deficit or full irrigation. Changes in plant physiology were recorded at two physiological stages with a multiparametric handheld fluorescence sensor and a fluorescence ima...

  5. Fluorescence spectral studies of Gum Arabic: Multi-emission of Gum Arabic in aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Dhenadhayalan, Namasivayam, E-mail: ndhena@gmail.com [Department of Chemistry, National Taiwan University, Taipei, Taiwan (China); Mythily, Rajan, E-mail: rajanmythily@gmail.com [Department of Chemistry, Dwaraka Doss Goverdhan Doss Vaishnav College (Autonomous), 833, Gokul Bagh, E.V.R. Periyar Road, Arumbakkam, Chennai 600 106 (India); Kumaran, Rajendran, E-mail: kumaranwau@rediffmail.com [Department of Chemistry, Dwaraka Doss Goverdhan Doss Vaishnav College (Autonomous), 833, Gokul Bagh, E.V.R. Periyar Road, Arumbakkam, Chennai 600 106 (India)

    2014-11-15

    Gum Arabic (GA), a food hydrocolloid is a natural composite obtained from the stems and branches of Acacia Senegal and Acacia Seyal trees. GA structure is made up of highly branched arabinogalactan polysaccharides. Steady-state absorption, fluorescence, and time-resolved fluorescence spectral studies of acid hydrolyzed GA solutions were carried out at various pH conditions. The fluorescence in GA is predominantly attributed to the presence of tyrosine and phenylalanine amino acids. The presence of multi-emissive peaks at different pH condition is attributed to the exposure of the fluorescing amino acids to the aqueous phase, which contains several sugar units, hydrophilic and hydrophobic moieties. Time-resolved fluorescence studies of GA exhibits a multi-exponential decay with different fluorescence lifetime of varying amplitude which confirms that tyrosine is confined to a heterogeneous microenvironment. The existence of multi-emissive peaks with large variation in the fluorescence intensities were established by 3D emission contour spectral studies. The probable location of the fluorophore in a heterogeneous environment was further ascertained by constructing a time-resolved emission spectrum (TRES) and time-resolved area normalized emission spectrum (TRANES) plots. Fluorescence spectral technique is used as an analytical tool in understanding the photophysical properties of a water soluble complex food hydrocolloid containing an intrinsic fluorophore located in a multiple environment is illustrated. - Highlights: • The Manuscript deals with the steady state absorption, emission, fluorescence lifetime and time-resolved emission spectrum studies of Gum Arabic in aqueous medium at various pH conditions. • The fluorescence emanates from the tyrosine amino acid present in GA. • Change in pH results in marked variation in the fluorescence spectral properties of tyrosine. • Fluorescence spectral techniques are employed as a tool in establishing the

  6. Two-photon excited fluorescence emission from hemoglobin

    Science.gov (United States)

    Sun, Qiqi; Zeng, Yan; Zhang, Wei; Zheng, Wei; Luo, Yi; Qu, Jianan Y.

    2015-03-01

    Hemoglobin, one of the most important proteins in blood, is responsible for oxygen transportation in almost all vertebrates. Recently, we discovered two-photon excited hemoglobin fluorescence and achieved label-free microvascular imaging based on the hemoglobin fluorescence. However, the mechanism of its fluorescence emission still remains unknown. In this work, we studied the two-photon excited fluorescence properties of the hemoglobin subunits, heme/hemin (iron (II)/(III) protoporphyrin IX) and globin. We first studied the properties of heme and the similar spectral and temporal characteristics of heme and hemoglobin fluorescence provide strong evidence that heme is the fluorophore in hemoglobin. Then we studied the fluorescence properties of hemin, globin and methemoglobin, and found that the hemin may have the main effect on the methemoglobin fluorescence and that globin has tryptophan fluorescence like other proteins. Finally, since heme is a centrosymmetric molecule, that the Soret band fluorescence of heme and hemoglobin was not observed in the single photon process in the previous study may be due to the parity selection rule. The discovery of heme two-photon excited fluorescence may open a new window for heme biology research, since heme as a cofactor of hemoprotein has many functions, including chemical catalysis, electron transfer and diatomic gases transportation.

  7. Flame emission, atomic absorption and fluorescence spectrometry

    International Nuclear Information System (INIS)

    Horlick, G.

    1980-01-01

    Six hundred and thirty references are cited in this review. The information in the review is divided into 12 major areas: books, reviews, and bibliographies; fundamental studies in flames; developments in instrumentation; measurement techniques and procedure; flame emission spectrometry; flame atomic absorption spectrometry; flame molecular absorption spectrometry; electrothermal atomization atomic absorption spectroscopy; hydride generation techniques; graphite furnace atomic emission spectrometry; atomic fluorescence spectrometry; and analytical comparisons

  8. Nitrogen oxide emissions from a kraft recovery furnace

    International Nuclear Information System (INIS)

    Prouty, A.L.; Stuart, R.C.; Caron, A.L.

    1993-01-01

    Nitrogen Oxide (NOx) emissions from a rebuilt kraft recovery furnace slightly exceeded the specified limit of 1.1 lb/ton (0.55 kg/metric ton) of black-liquor solids. Mill trials were undertaken to determine whether NOx emissions could be minimized by modifying furnace operation. NOx emissions increased when secondary air was shifted to tertiary ports. NOx emissions fell when the amounts of primary and total air were decreased, but this increased emissions of other pollutants. After demonstrating that best operation of the furnace could not meet the permit with an emissions limit that matched the furnace's performance at best operation

  9. Creating infinite contrast in fluorescence microscopy by using lanthanide centered emission

    DEFF Research Database (Denmark)

    R. Carro-Temboury, Miguel; Arppe, Riikka Matleena; Hempel, Casper

    2017-01-01

    The popularity of fluorescence microscopy arises from the inherent mode of action, where the fluorescence emission from probes is used to visualize selected features on a presumed dark background. However, the background is rarely truly dark, and image processing and analysis is needed to enhance...... the fluorescent signal that is ascribed to the selected feature. The image acquisition is facilitated by using considerable illumination, bright probes at a relatively high concentration in order to make the fluorescent signal significantly more intense than the background signal. Here, we present two methods......, while method II resolves the fluorescent signal by subtracting a background calculated via the gradient. Both methods improve signal-to-background ratio significantly and we suggest that spectral imaging of lanthanide-centered emission can be used as a tool to obtain absolute contrast in bioimaging....

  10. Greenhouse gas emissions in salt marshes and their response to nitrogen loading

    Science.gov (United States)

    Tang, J.; Moseman-Valtierra, S.; Kroeger, K. D.; Morkeski, K.; Carey, J.

    2015-12-01

    Salt marshes play an important role in global and regional carbon and nitrogen cycling. Anthropogenic nitrogen loading may alter greenhouse gas (GHG, including CO2, CH4, and N2O) emissions and carbon sequestration in salt marshes. We measured GHG emissions biweekly for two growing seasons across a nitrogen-loading gradient of four Spartina salt marshes in Waquoit Bay, Massachusetts. In addition, we conducted nitrogen addition experiments in a pristine marsh by adding low and high nitrate bi-weekly during the summer. The GHG flux measurements were made in situ with a state-of-the-art mobile gas measurement system using the cavity ring down technology that consists of a CO2/CH4 analyzer (Picarro) and an N2O/CO analyzer (Los Gatos). We observed strong seasonal variations in greenhouse gas emissions. The differences in gas emissions across the nitrogen gradient (between 1 and 10 gN m-2y-1) were not significant, but strong pulse emissions of N2O were observed after nitrogen was artificially added to the marsh. We found that the studied salt marsh was a significant carbon sink (NEP ~ 380 gC m-2y-1). CH4 fluxes are 3 orders of magnitude less than CO2 fluxes in the salt marsh. Carbon fluxes are driven by light, salinity, tide, and temperature. We conclude that restoration or conservation of this carbon sink has a significant social benefit for carbon credit.

  11. Dual fluorescence and laser emissions from fluorescein-Na and eosin-B

    International Nuclear Information System (INIS)

    Math, N.N.; Naik, L.R.; Suresh, H.M.; Inamdar, S.R.

    2006-01-01

    Dual laser emissions were observed from fluorescein-Na and eosin-B in ethanolic solutions individually in the concentration range from 10 -2 to 10 -3 mol dm -3 under N 2 laser excitation. The first compound was found to lase at two distinct regions with wavelength maxima around 540, 550 nm, while the second one around 558, 574 nm. Steady-state absorption, fluorescence excitation, fluorescence polarization, fluorescence emission and decays of the dyes in various solvents under varying conditions of excitation and detection systems were carried out to identify the nature of the emitting species responsible for laser emissions in two distinct regions. Both the dyes exhibited concentration and excitation wavelength dependence of fluorescence and the effects were found to be more pronounced in binary solution. The fluorescence decays of dyes were monoexponential in ethanol, while in some other solvents used, the decays showed biexponential behavior. The absorption and excitation studies using thin layers of solutions revealed the formation of dimers with the dye concentration around 1x10 -3 mol dm -3 . Fluorescence polarization and decay studies confirmed the presence of dimers. The two laser bands observed in the shorter and longer wavelengths were respectively ascribed to monomeric and dimeric species

  12. Dual fluorescence and laser emissions from fluorescein-Na and eosin-B

    Energy Technology Data Exchange (ETDEWEB)

    Math, N.N. [Laser Spectroscopy (DRDO/KU) Programme, Department of Physics, Karnatak University, Dharwad 580 003 (India)]. E-mail: nnm31@rediffmail.com; Naik, L.R. [Laser Spectroscopy (DRDO/KU) Programme, Department of Physics, Karnatak University, Dharwad 580 003 (India); Suresh, H.M. [Laser Spectroscopy (DRDO/KU) Programme, Department of Physics, Karnatak University, Dharwad 580 003 (India); Inamdar, S.R. [Laser Spectroscopy (DRDO/KU) Programme, Department of Physics, Karnatak University, Dharwad 580 003 (India)

    2006-12-15

    Dual laser emissions were observed from fluorescein-Na and eosin-B in ethanolic solutions individually in the concentration range from 10{sup -2} to 10{sup -3} mol dm{sup -3} under N{sub 2} laser excitation. The first compound was found to lase at two distinct regions with wavelength maxima around 540, 550 nm, while the second one around 558, 574 nm. Steady-state absorption, fluorescence excitation, fluorescence polarization, fluorescence emission and decays of the dyes in various solvents under varying conditions of excitation and detection systems were carried out to identify the nature of the emitting species responsible for laser emissions in two distinct regions. Both the dyes exhibited concentration and excitation wavelength dependence of fluorescence and the effects were found to be more pronounced in binary solution. The fluorescence decays of dyes were monoexponential in ethanol, while in some other solvents used, the decays showed biexponential behavior. The absorption and excitation studies using thin layers of solutions revealed the formation of dimers with the dye concentration around 1x10{sup -3} mol dm{sup -3}. Fluorescence polarization and decay studies confirmed the presence of dimers. The two laser bands observed in the shorter and longer wavelengths were respectively ascribed to monomeric and dimeric species.

  13. Biexciton emission from single isoelectronic traps formed by nitrogen-nitrogen pairs in GaAs

    Energy Technology Data Exchange (ETDEWEB)

    Takamiya, Kengo; Fukushima, Toshiyuki; Yagi, Shuhei; Hijikata, Yasuto; Yaguchi, Hiroyuki [Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura-ku , Saitama 338-8570 (Japan); Mochizuki, Toshimitsu; Yoshita, Masahiro; Akiyama, Hidefumi [Institute for Solid State Physics, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581 (Japan); Kuboya, Shigeyuki; Onabe, Kentaro [Department of Advanced Materials Science, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8581 (Japan); Katayama, Ryuji [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan)

    2013-12-04

    We have studied photoluminescence (PL) from individual isoelectronic traps formed by nitrogen-nitrogen (NN) pairs in GaAs. Sharp emission lines due to exciton and biexciton were observed from individual isoelectronic traps in nitrogen atomic-layer doped (ALD) GaAs. The binding energy of biexciton bound to individual isoelectronic traps was approximately 8 meV. Both the exciton and biexciton luminescence lines show completely random polarization and no fine-structure splitting. These results are desirable to the application to the quantum cryptography used in the field of quantum information technology.

  14. Terahertz-Radiation-Enhanced Emission of Fluorescence from Gas Plasma

    International Nuclear Information System (INIS)

    Liu Jingle; Zhang, X.-C.

    2009-01-01

    We report the study of femtosecond laser-induced air plasma fluorescence under the illumination of terahertz (THz) pulses. Semiclassical modeling and experimental verification indicate that time-resolved THz radiation-enhanced emission of fluorescence is dominated by the electron kinetics and the electron-impact excitation of gas molecules or ions. We demonstrate that the temporal waveform of the THz field could be retrieved from the transient enhanced fluorescence, making omnidirectional, coherent detection available for THz time-domain spectroscopy.

  15. Influence of nitrogen loading and plant nitrogen assimilation on nitrogen leaching and N₂O emission in forage rice paddy fields fertilized with liquid cattle waste.

    Science.gov (United States)

    Riya, Shohei; Zhou, Sheng; Kobara, Yuso; Sagehashi, Masaki; Terada, Akihiko; Hosomi, Masaaki

    2015-04-01

    Livestock wastewater disposal onto rice paddy fields is a cost- and labor-effective way to treat wastewater and cultivate rice crops. We evaluated the influence of nitrogen loading rates on nitrogen assimilation by rice plants and on nitrogen losses (leaching and N2O emission) in forage rice fields receiving liquid cattle waste (LCW). Four forage rice fields were subjected to nitrogen loads of 107, 258, 522, and 786 kg N ha(-1) (N100, N250, N500, and N750, respectively) using basal fertilizer (chemical fertilizer) (50 kg N ha(-1)) and three LCW topdressings (each 57-284 kg N ha(-1)). Nitrogen assimilated by rice plants increased over time. However, after the third topdressing, the nitrogen content of the biomass did not increase in any treatment. Harvested aboveground biomass contained 93, 60, 33, and 31 % of applied nitrogen in N100, N250, N500, and N750, respectively. The NH4 (+) concentration in the pore water at a depth of 20 cm was less than 1 mg N L(-1) in N100, N250, and N500 throughout the cultivation period, while the NH4 (+) concentration in N750 increased to 3 mg N L(-1) after the third topdressing. Cumulative N2O emissions ranged from -0.042 to 2.39 kg N ha(-1); the highest value was observed in N750, followed by N500. In N750, N2O emitted during the final drainage accounted for 80 % of cumulative N2O emissions. This study suggested that 100-258 kg N ha(-1) is a recommended nitrogen loading rate for nitrogen recovery by rice plants without negative environmental impacts such as groundwater pollution and N2O emission.

  16. Synthesis and formation mechanistic investigation of nitrogen-doped carbon dots with high quantum yields and yellowish-green fluorescence

    Science.gov (United States)

    Hou, Juan; Wang, Wei; Zhou, Tianyu; Wang, Bo; Li, Huiyu; Ding, Lan

    2016-05-01

    Heteroatom doped carbon dots (CDs) have received increasing attention due to their unique properties and related applications. However, previously reported CDs generally show strong emission only in the blue-light region, thus restricting their further applications. And the fundamental investigation on the preparation process is always neglected. Herein, we have developed a simple and solvent-free synthetic strategy to fabricate nitrogen-doped CDs (N-CDs) from citric acid and dicyandiamide. The as-prepared N-CDs exhibited a uniform size distribution, strong yellowish-green fluorescence emission and a high quantum yield of 73.2%. The products obtained at different formation stages were detailedly characterized by transmission electron microscopy, X-ray diffraction spectrometer, X-ray photoelectron spectroscopy and UV absorbance spectroscopy. A possible formation mechanism has thus been proposed including dehydration, polymerization and carbonization. Furthermore, the N-CDs could serve as a facile and label-free probe for the detection of iron and fluorine ions with detection limits of 50 nmol L-1 and 75 nmol L-1, respectively.Heteroatom doped carbon dots (CDs) have received increasing attention due to their unique properties and related applications. However, previously reported CDs generally show strong emission only in the blue-light region, thus restricting their further applications. And the fundamental investigation on the preparation process is always neglected. Herein, we have developed a simple and solvent-free synthetic strategy to fabricate nitrogen-doped CDs (N-CDs) from citric acid and dicyandiamide. The as-prepared N-CDs exhibited a uniform size distribution, strong yellowish-green fluorescence emission and a high quantum yield of 73.2%. The products obtained at different formation stages were detailedly characterized by transmission electron microscopy, X-ray diffraction spectrometer, X-ray photoelectron spectroscopy and UV absorbance spectroscopy. A

  17. 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.

  18. Delayed addition of nitrogen-rich substrates during composting of municipal waste: Effects on nitrogen loss, greenhouse gas emissions and compost stability.

    Science.gov (United States)

    Nigussie, Abebe; Bruun, Sander; Kuyper, Thomas W; de Neergaard, Andreas

    2017-01-01

    Municipal waste is usually composted with an N-rich substrate, such as manure, to increase the N content of the product. This means that a significant amount of nitrogen can be lost during composting. The objectives of this study were (i) to investigate the effect of split addition of a nitrogen-rich substrate (poultry manure) on nitrogen losses and greenhouse gas emissions during composting and to link this effect to different bulking agents (coffee husks and sawdust), and (ii) to assess the effect of split addition of a nitrogen-rich substrate on compost stability and sanitisation. The results showed that split addition of the nitrogen-rich substrate reduced nitrogen losses by 9% when sawdust was used and 20% when coffee husks were used as the bulking agent. Depending on the bulking agent used, split addition increased cumulative N 2 O emissions by 400-600% compared to single addition. In contrast, single addition increased methane emissions by up to 50% compared to split addition of the substrate. Hence, the timing of the addition of the N-rich substrate had only a marginal effect on total non-CO 2 greenhouse gas emissions. Split addition of the N-rich substrate resulted in compost that was just as stable and effective at completely eradicating weed seeds as single addition. These findings therefore show that split addition of a nitrogen-rich substrate could be an option for increasing the fertilising value of municipal waste compost without having a significant effect on total greenhouse gas emissions or compost stability. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. 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

  20. Biological soil crusts accelerate the nitrogen cycle through large NO and HONO emissions in drylands.

    Science.gov (United States)

    Weber, Bettina; Wu, Dianming; Tamm, Alexandra; Ruckteschler, Nina; Rodríguez-Caballero, Emilio; Steinkamp, Jörg; Meusel, Hannah; Elbert, Wolfgang; Behrendt, Thomas; Sörgel, Matthias; Cheng, Yafang; Crutzen, Paul J; Su, Hang; Pöschl, Ulrich

    2015-12-15

    Reactive nitrogen species have a strong influence on atmospheric chemistry and climate, tightly coupling the Earth's nitrogen cycle with microbial activity in the biosphere. Their sources, however, are not well constrained, especially in dryland regions accounting for a major fraction of the global land surface. Here, we show that biological soil crusts (biocrusts) are emitters of nitric oxide (NO) and nitrous acid (HONO). Largest fluxes are obtained by dark cyanobacteria-dominated biocrusts, being ∼20 times higher than those of neighboring uncrusted soils. Based on laboratory, field, and satellite measurement data, we obtain a best estimate of ∼1.7 Tg per year for the global emission of reactive nitrogen from biocrusts (1.1 Tg a(-1) of NO-N and 0.6 Tg a(-1) of HONO-N), corresponding to ∼20% of global nitrogen oxide emissions from soils under natural vegetation. On continental scales, emissions are highest in Africa and South America and lowest in Europe. Our results suggest that dryland emissions of reactive nitrogen are largely driven by biocrusts rather than the underlying soil. They help to explain enigmatic discrepancies between measurement and modeling approaches of global reactive nitrogen emissions. As the emissions of biocrusts strongly depend on precipitation events, climate change affecting the distribution and frequency of precipitation may have a strong impact on terrestrial emissions of reactive nitrogen and related climate feedback effects. Because biocrusts also account for a large fraction of global terrestrial biological nitrogen fixation, their impacts should be further quantified and included in regional and global models of air chemistry, biogeochemistry, and climate.

  1. Optical radiation emissions from compact fluorescent lamps

    International Nuclear Information System (INIS)

    Khazova, M.; O'Hagan, J.B.

    2008-01-01

    There is a drive to energy efficiency to mitigate climate change. To meet this challenge, the UK Government has proposed phasing out incandescent lamps by the end of 2011 and replacing them with energy efficient fluorescent lighting, including compact fluorescent lamps (CFLs) with integrated ballasts. This paper presents a summary of an assessment conducted by the Health Protection Agency in March 2008 to evaluate the optical radiation emissions of CFLs currently available in the UK consumer market. The study concluded that the UV emissions from a significant percentage of the tested CFLs with single envelopes may result in foreseeable overexposure of the skin when these lamps are used in desk or task lighting applications. The optical output of all tested CFLs, in addition to high-frequency modulation, had a 100-Hz envelope with modulation in excess of 15%. This degree of modulation may be linked to a number of adverse effects. (authors)

  2. Ratiometric Fluorescence Azide-Alkyne Cycloaddition for Live Mammalian Cell Imaging.

    Science.gov (United States)

    Fu, Hongxia; Li, Yanru; Sun, Lingbo; He, Pan; Duan, Xinrui

    2015-11-17

    Click chemistry with metabolic labeling has been widely used for selectively imaging biomacromolecules in cells. The first example of azide-alkyne cycloaddition for ratiometric fluorescent imaging of live cells is reported. The precursor of the azido fluorophore (cresyl violet) has a fluorescence emission peak at 620 nm. The electron-rich nitrogen of the azido group blue-shifts the emission peak to 566 nm. When the click reaction occurs, an emission peak appears at 620 nm due to the lower electronic density of the newly formed triazole ring, which allows us to ratiometrically record fluorescence signals. This emission shift was applied to ratiometric imaging of propargylcholine- and dibenzocyclooctyne-labeled human breast cancer cells MCF-7 under laser confocal microscopy. Two typical triazole compounds were isolated for photophysical parameter measurements. The emission spectra presented a fluorescence emission peak around 620 nm for both click products. The results further confirmed the emission wavelength change was the result of azide-alkyne cycloaddition reaction. Since nearly all biomolecules can be metabolically labeled by reported alkyne-functionalized derivatives of native metabolites, our method can be readily applied to image these biomacromolecules.

  3. Influence of carbohydrate addition on nitrogen transformations and greenhouse gas emissions of intensive aquaculture system.

    Science.gov (United States)

    Hu, Zhen; Lee, Jae Woo; Chandran, Kartik; Kim, Sungpyo; Sharma, Keshab; Khanal, Samir Kumar

    2014-02-01

    Aquaculture is one of the fastest-growing segments of the food economy in modern times. It is also being considered as an important source of greenhouse gas (GHG) emissions. To date, limited studies have been conducted on GHG emissions from aquaculture system. In this study, daily addition of fish feed and soluble starch at a carbon-to-nitrogen (C/N) ratio of 16:1 (w/w) was used to examine the effects of carbohydrate addition on nitrogen transformations and GHG emissions in a zero-water exchange intensive aquaculture system. The addition of soluble starch stimulated heterotrophic bacterial growth and denitrification, which led to lower total ammonia nitrogen, nitrite and nitrate concentrations in aqueous phase. About 76.2% of the nitrogen output was emitted in the form of gaseous nitrogen (i.e., N2 and N2O) in the treatment tank (i.e., aquaculture tank with soluble starch addition), while gaseous nitrogen accounted for 33.3% of the nitrogen output in the control tank (i.e., aquaculture tank without soluble starch addition). Although soluble starch addition reduced daily N2O emissions by 83.4%, it resulted in an increase of daily carbon dioxide (CO2) emissions by 91.1%. Overall, starch addition did not contribute to controlling the GHG emissions from the aquaculture system. © 2013.

  4. Potential mercury emissions from fluorescent lamps production and obsolescence in mainland China.

    Science.gov (United States)

    Tan, Quanyin; Li, Jinhui

    2016-01-01

    The use of fluorescent lamps has expanded rapidly all over the world in recent years, because of their energy-saving capability. Consequently, however, mercury emissions from production, breakage, and discard of the lamps are drawing increasing concern from the public. This article focuses on evaluating the amount of mercury used for fluorescent lamp production, as well as the potential mercury emissions during production and breakage, in mainland China. It is expected to provide a comprehensive understanding about the risks present in the mercury from fluorescent lamps, and to know about the impacts of the policies on fluorescent lamps after their implementation. It is estimated that, in 2020, mercury consumption will be about 11.30-15.69 tonnes, a significant reduction of 34.9%-37.4% from that used in 2013, owing to improvement in mercury dosing dosage technology and tighter limitations on mercury content in fluorescent lamps. With these improvements, the amount of mercury remaining in fluorescent lamps and released during production is estimated to be 10.71-14.86 and 0.59-0.83 tonnes, respectively; the mercury released from waste fluorescent lamps is estimated to be about 5.37-7.59 tonnes. Also, a significant reduction to the mercury emission can be expected when a collection and treatment system is well established and conducted in the future. © The Author(s) 2015.

  5. Light emitting diode excitation emission matrix fluorescence spectroscopy.

    Science.gov (United States)

    Hart, Sean J; JiJi, Renée D

    2002-12-01

    An excitation emission matrix (EEM) fluorescence instrument has been developed using a linear array of light emitting diodes (LED). The wavelengths covered extend from the upper UV through the visible spectrum: 370-640 nm. Using an LED array to excite fluorescence emission at multiple excitation wavelengths is a low-cost alternative to an expensive high power lamp and imaging spectrograph. The LED-EEM system is a departure from other EEM spectroscopy systems in that LEDs often have broad excitation ranges which may overlap with neighboring channels. The LED array can be considered a hybrid between a spectroscopic and sensor system, as the broad LED excitation range produces a partially selective optical measurement. The instrument has been tested and characterized using fluorescent dyes: limits of detection (LOD) for 9,10-bis(phenylethynyl)-anthracene and rhodamine B were in the mid parts-per-trillion range; detection limits for the other compounds were in the low parts-per-billion range (LED-EEMs were analyzed using parallel factor analysis (PARAFAC), which allowed the mathematical resolution of the individual contributions of the mono- and dianion fluorescein tautomers a priori. Correct identification and quantitation of six fluorescent dyes in two to six component mixtures (concentrations between 12.5 and 500 ppb) has been achieved with root mean squared errors of prediction (RMSEP) of less than 4.0 ppb for all components.

  6. 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.

  7. X-ray emission spectroscopy. X-ray fluorescence

    International Nuclear Information System (INIS)

    Despujols, J.

    1992-01-01

    Principles of X-ray emission spectrometry are first recalled, then wave-length dispersive and energy dispersive X-ray fluorescence spectrometer are described. They are essentially designed for qualitative and quantitative analysis of elements (Z>10). Sample preparation, calibration, corrections, interferences, accuracy are reviewed. Examples of use in different industries are given. (71 refs.)

  8. Nitrogen efficiency of dairy cattle : from protein evaluation to ammonia emission

    NARCIS (Netherlands)

    Duinkerken, van G.

    2011-01-01

    Diet optimization contributes considerably to increased nitrogen efficiency of dairy cattle, resulting in reduced nitrogen losses. This thesis focuses on three themes: the potential advances in protein evaluation systems for ruminants, the relationship between dairy cow diet and ammonia emission

  9. Emissions of nitrogen oxides and particulates of diesel vehicles

    OpenAIRE

    Kadijk, G.; Ligterink, N.E.; Mensch, P. van; Spreen, J.S.; Vermeulen, R.J.; Vonk, W.A.

    2015-01-01

    In real-world conditions, modern Euro VI heavy-duty vehicles produce an average of ten times less nitrogen oxide (NOx)emissions than previous generations of Euro IV and Euro V heavy-duty vehicles. However, Euro 6 passenger cars and light commercial vehicles present an entirely different picture since, despite a continual tightening of European emissions limits, the real-world NOx emissions of new diesel passenger cars and light commercial vehicles have remained virtually unchanged over the la...

  10. Nitrogen emission and deposition budget in West and Central Africa

    International Nuclear Information System (INIS)

    Galy-Lacaux, C; Delon, C

    2014-01-01

    Atmospheric nitrogen depends on land surface exchanges of nitrogen compounds. In Sub Saharan Africa, deposition and emission fluxes of nitrogen compounds are poorly quantified, and are likely to increase in the near future due to land use change and anthropogenic pressure. This work proposes an estimate of atmospheric N compounds budget in West and Central Africa, along an ecosystem transect, from dry savanna to wet savanna and forest, for years 2000−2007. The budget may be considered as a one point in time budget, to be included in long term studies as one of the first reference point for Sub Saharan Africa. Gaseous dry deposition fluxes are estimated by considering N compounds concentrations measured in the frame of the IDAF network (IGAC/DEBITS/AFrica) at the monthly scale and modeling of deposition velocities at the IDAF sites, taking into account the bi directional exchange of ammonia. Particulate dry deposition fluxes are calculated using the same inferential method. Wet deposition fluxes are calculated from measurements of ammonium and nitrate chemical content in precipitations at the IDAF sites combined with the annual rainfall amount. In terms of emission, biogenic NO emissions are simulated at each IDAF site with a surface model coupled to an emission module elaborated from an artificial neural network equation. Ammonia emissions from volatilization are calculated from literature data on livestock quantity in each country and N content in manure. NO x and NH 3 emission from biomass burning and domestic fires are estimated from satellite data and emission factors. The total budget shows that emission sources of nitrogen compounds are in equilibrium with deposition fluxes in dry and wet savannas, with respectively 7.40 (±1.90) deposited and 9.01 (±3.44) kgN ha −1 yr −1 emitted in dry savanna, 8.38 (±2.04) kgN ha −1 yr −1 deposited and 9.60 (±0.69) kgN ha −1 yr −1 emitted in wet savanna. In forested ecosystems, the total budget is dominated

  11. Fabrication of fluorescent silica nanoparticles with aggregation-induced emission luminogens for cell imaging.

    Science.gov (United States)

    Chen, Sijie; Lam, Jacky W Y; Tang, Ben Zhong

    2013-01-01

    Fluorescence-based techniques have found wide applications in life science. Among various luminogenic materials, fluorescent nanoparticles have attracted much attention due to their fabulous emission properties and potential applications as sensors. Here, we describe the fabrication of fluorescent silica nanoparticles (FSNPs) containing aggregation-induced emission (AIE) luminogens. By employing surfactant-free sol-gel reaction, FSNPs with uniform size and high surface charge and colloidal stability are generated. The FSNPs emit strong light upon photoexcitation, due to the AIE characteristic of the silole -aggregates in the hybrid nanoparticles. The FSNPs are cytocompatible and can be utilized as fluorescent visualizer for intracellular imaging for HeLa cells.

  12. 40 CFR 89.112 - Oxides of nitrogen, carbon monoxide, hydrocarbon, and particulate matter exhaust emission standards.

    Science.gov (United States)

    2010-07-01

    ....112 Oxides of nitrogen, carbon monoxide, hydrocarbon, and particulate matter exhaust emission... emissions of oxides of nitrogen, carbon monoxide, hydrocarbon, and nonmethane hydrocarbon are measured using... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Oxides of nitrogen, carbon monoxide...

  13. Creating infinite contrast in fluorescence microscopy by using lanthanide centered emission

    DEFF Research Database (Denmark)

    R. Carro-Temboury, Miguel; Arppe, Riikka Matleena; Hempel, Casper

    2017-01-01

    The popularity of fluorescence microscopy arises from the inherent mode of action, where the fluorescence emission from probes is used to visualize selected features on a presumed dark background. However, the background is rarely truly dark, and image processing and analysis is needed to enhance...

  14. Emissions of gaseous nitrogen species from manure management: A new approach

    International Nuclear Information System (INIS)

    Daemmgen, Ulrich; Hutchings, Nicholas J.

    2008-01-01

    A procedure for the assessment of emissions of nitrogen (N) species (ammonia, nitrous oxide, nitric oxide, di-nitrogen) from the manure management system is developed, which treats N pools and flows including emissions strictly according to conservation of mass criteria. As all relevant flows in the husbandry of mammals are depicted, the methodology is considered a Tier 3 approach in IPCC terminology or a detailed methodology in UN ECE terminology. The importance of accounting for all N species is illustrated by comparing emission estimates obtained using this approach with those obtained from the application the present detailed/Tier 2 methodology. - A cow is a cow. There is no distinction between an IPCC and a UN ECE cow!

  15. Emissions of gaseous nitrogen species from manure management: A new approach

    Energy Technology Data Exchange (ETDEWEB)

    Daemmgen, Ulrich [Federal Agricultural Research Centre, Institute of Agroecology, Bundesallee 50, 38116 Braunschweig (Germany)], E-mail: ulrich.daemmgen@fal.de; Hutchings, Nicholas J. [Danish Institute of Agricultural Sciences, Department of Agroecology, Tjele (Denmark)], E-mail: nick.hutchings@agrsci.dk

    2008-08-15

    A procedure for the assessment of emissions of nitrogen (N) species (ammonia, nitrous oxide, nitric oxide, di-nitrogen) from the manure management system is developed, which treats N pools and flows including emissions strictly according to conservation of mass criteria. As all relevant flows in the husbandry of mammals are depicted, the methodology is considered a Tier 3 approach in IPCC terminology or a detailed methodology in UN ECE terminology. The importance of accounting for all N species is illustrated by comparing emission estimates obtained using this approach with those obtained from the application the present detailed/Tier 2 methodology. - A cow is a cow. There is no distinction between an IPCC and a UN ECE cow{exclamation_point}.

  16. Reduction of greenhouse gas emissions in the rape cultivation with special consideration of nitrogen fertilization

    International Nuclear Information System (INIS)

    Heilmann, Hubert; Riemer, Doerte

    2017-01-01

    Involved into the research project ''Mitigation of greenhouse gas emissions in oilseed rape cropping with special consideration of nitrogen fertilizing'' regional specific GHG cropping emissions according to benchmark and regional experts are calculated by using a calculation method developed in cooperation with IFEU and according to IPCC (2006). The following results are achieved for 35 German NUTS2-regions: - nitrogen fertilization is the main influence for GHG emission reduction; - the use of low-emission nitrogen fertilizers is worth for GHG emission reduction; - without increasing the nutrient efficiency of organic fertilizers, GHG emission reductions are difficult to achieve in many regions; - GHG emission reduction/climate protection and realization of the WRRL or N-Saldo reduction come up to the same aim; - economic consequences of restrictive carbon mitigation can be compensated by slight price surcharges for certified raw material.

  17. Light emission from compound eye with conformal fluorescent coating

    Science.gov (United States)

    Martín-Palma, Raúl J.; Miller, Amy E.; Pulsifer, Drew P.; Lakhtakia, Akhlesh

    2015-03-01

    Compound eyes of insects are attractive biological systems for engineered biomimicry as artificial sources of light, given their characteristic wide angular field of view. A blowfly eye was coated with a thin conformal fluorescent film, with the aim of achieving wide field-of-view emission. Experimental results showed that the coated eye emitted visible light and that the intensity showed a weaker angular dependence than a fluorescent thin film deposited on a flat surface.

  18. Saturated virtual fluorescence emission difference microscopy based on detector array

    Science.gov (United States)

    Liu, Shaocong; Sun, Shiyi; Kuang, Cuifang; Ge, Baoliang; Wang, Wensheng; Liu, Xu

    2017-07-01

    Virtual fluorescence emission difference microscopy (vFED) has been proposed recently to enhance the lateral resolution of confocal microscopy with a detector array, implemented by scanning a doughnut-shaped pattern. Theoretically, the resolution can be enhanced by around 1.3-fold compared with that in confocal microscopy. For further improvement of the resolving ability of vFED, a novel method is presented utilizing fluorescence saturation for super-resolution imaging, which we called saturated virtual fluorescence emission difference microscopy (svFED). With a point detector array, matched solid and hollow point spread functions (PSF) can be obtained by photon reassignment, and the difference results between them can be used to boost the transverse resolution. Results show that the diffraction barrier can be surpassed by at least 34% compared with that in vFED and the resolution is around 2-fold higher than that in confocal microscopy.

  19. Stimulated emission depletion microscopy resolves individual nitrogen vacancy centers in diamond nanocrystals.

    Science.gov (United States)

    Arroyo-Camejo, Silvia; Adam, Marie-Pierre; Besbes, Mondher; Hugonin, Jean-Paul; Jacques, Vincent; Greffet, Jean-Jacques; Roch, Jean-François; Hell, Stefan W; Treussart, François

    2013-12-23

    Nitrogen-vacancy (NV) color centers in nanodiamonds are highly promising for bioimaging and sensing. However, resolving individual NV centers within nanodiamond particles and the controlled addressing and readout of their spin state has remained a major challenge. Spatially stochastic super-resolution techniques cannot provide this capability in principle, whereas coordinate-controlled super-resolution imaging methods, like stimulated emission depletion (STED) microscopy, have been predicted to fail in nanodiamonds. Here we show that, contrary to these predictions, STED can resolve single NV centers in 40-250 nm sized nanodiamonds with a resolution of ≈10 nm. Even multiple adjacent NVs located in single nanodiamonds can be imaged individually down to relative distances of ≈15 nm. Far-field optical super-resolution of NVs inside nanodiamonds is highly relevant for bioimaging applications of these fluorescent nanolabels. The targeted addressing and readout of individual NV(-) spins inside nanodiamonds by STED should also be of high significance for quantum sensing and information applications.

  20. Plasma characterization using terahertz-wave-enhanced fluorescence

    International Nuclear Information System (INIS)

    Liu Jingle; Zhang, X.-C.

    2010-01-01

    We demonstrate that the terahertz-wave-enhanced fluorescence emission from excited atoms or molecules can be employed in the characterization of laser-induced gas plasmas. The electron relaxation time and plasma density were deduced through applying the electron impact excitation/ionization and electron-ion recombination processes to the measured time-dependent enhanced fluorescence. The electron collision dynamics of nitrogen plasma excited at different gas pressures and laser pulse energies have been systematically investigated. This plasma characterization method provides picosecond temporal resolution and enables omnidirectional optical signal collection.

  1. Donor-acceptor-pair emission characterization in N-B doped fluorescent SiC

    DEFF Research Database (Denmark)

    Ou, Yiyu; Jokubavicius, Valdas; Kamiyama, Satoshi

    2011-01-01

    In the present work, we investigated donor-acceptor-pair emission in N-B doped fluorescent 6H-SiC, by means of photoluminescence, Raman spectroscopy, and angle-resolved photoluminescence. The photoluminescence results were interpreted by using a band diagram with Fermi-Dirac statistics. It is shown...... intensity in a large emission angle range was achieved from angle-resolved photoluminescence. The results indicate N-B doped fluorescent SiC as a good wavelength converter in white LEDs applications....

  2. Highly selective detection of p-nitrophenol using fluorescence assay based on boron, nitrogen co-doped carbon dots.

    Science.gov (United States)

    Xiao, Na; Liu, Shi Gang; Mo, Shi; Li, Na; Ju, Yan Jun; Ling, Yu; Li, Nian Bing; Luo, Hong Qun

    2018-07-01

    p-Nitrophenol (p-NP) contaminants seriously endanger environmental and living beings health, hence to establish a sensitive and selective method is of great importance for the determination of p-NP. In this work, boron and nitrogen co-doped carbon dots (B,N-CDs) were synthesized by one-step hydrothermal method using 3-aminophenylboronic acid as the sole precursor. The product was characterized through high-resolution transmission electron microscopy, fluorescence spectroscopy, UV-visible absorption spectroscopy, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy. Without any functionalized modification, B,N-CDs can be directly applied as a 'turn-off' fluorescent probe for rapid, highly selective, and sensitive detection of p-NP. The fluorescent sensor based on the B,N-CDs exhibited a broad linear response to the concentration of p-NP in the range of 0.5 - 60 μM and 60 - 200 μM, respectively, and provided a detection limit of 0.2 μM. It was found that only the absorption spectrum of p-NP has a wide overlap with the fluorescence excitation and emission spectra of B,N-CDs compared to those of other representative analogues. The response mechanism was due to the inner filter effect and the formation of dynamic covalent B-O bonds between B,N-CDs and p-NP, which endowed the sensing platform with the rapid response and high selectivity to p-NP. Finally, the sensor showed the practicability of p-NP determination in environmental water samples. Copyright © 2018 Elsevier B.V. All rights reserved.

  3. Fluorescence excitation-emission matrix spectroscopy of vitiligo skin in vivo (Conference Presentation)

    Science.gov (United States)

    Zhao, Jianhua; Richer, Vincent; Al Jasser, Mohammed; Zandi, Soodabeh; Kollias, Nikiforos; Kalia, Sunil; Zeng, Haishan; Lui, Harvey

    2016-02-01

    Fluorescence signals depend on the intensity of the exciting light, the absorption properties of the constituent molecules, and the efficiency with which the absorbed photons are converted to fluorescence emission. The optical features and appearance of vitiligo have been explained primarily on the basis of reduced epidermal pigmentation, which results in abnormal white patches on the skin. The objective of this study is to explore the fluorescence properties of vitiligo and its adjacent normal skin using fluorescence excitation-emission matrix (EEM) spectroscopy. Thirty five (35) volunteers with vitiligo were acquired using a double-grating spectrofluorometer with excitation and emission wavelengths of 260-450 nm and 300-700 nm respectively. As expected, the most pronounced difference between the spectra obtained from vitiligo lesions compared to normally pigmented skin was that the overall fluorescence was much higher in vitiligo; these differences increased at shorter wavelengths, thus matching the characteristic spectral absorption of epidermal melanin. When comparing the fluorescence spectra from vitiligo to normal skin we detected three distinct spectral bands centered at 280nm, 310nm, and 335nm. The 280nm band may possibly be related to inflammation, whereas the 335 nm band may arise from collagen or keratin cross links. The source of the 310 nm band is uncertain; it is interesting to note its proximity to the 311 nm UV lamps used for vitiligo phototherapy. These differences are accounted for not only by changes in epidermal pigment content, but also by other optically active cutaneous biomolecules.

  4. Light stress effect and by nitrogen deficiency in plants of Petiveria alliacea measured with two-chlorophyll-fluorescence technique

    Science.gov (United States)

    Zuluaga, H.; Oviedo, A.; Solarte, Efrain; Pena, E. J.

    2004-10-01

    The chlorophyll fluorescence was studied in Petiveria alliacea plants exposed to different nitrogen concentrations and light radiation, the response was measured by two different forms; (1) measuring the photosynthetic efficiency with a pulse amplitude modulated fluorometro (PAM) emitted by a 650 nm diode and (2) measuring the fluorescence spectra caused by high power 452 nm diode with a SD2000 spectrometer. It was found out that the photosynthetic efficiency decreased in the plants exposed to high radiance and low nitrogen. Two chlorophyll fluorescence peaks were observed on 684 nm and 739 nm, the intensities in this wavelengths are inversely related with the light radiance. The correlation between the FIR and photosynthetic efficiency was very strong (r2 = -0.809, p Alliacea plants.

  5. 40 CFR 60.4320 - What emission limits must I meet for nitrogen oxides (NOX)?

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false What emission limits must I meet for nitrogen oxides (NOX)? 60.4320 Section 60.4320 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... nitrogen oxides (NOX)? (a) You must meet the emission limits for NOX specified in Table 1 to this subpart...

  6. Spectral and angle dependent emission of solar fluorescence collectors

    Energy Technology Data Exchange (ETDEWEB)

    Straeter, Hendrik; Knabe, Sebastian; Bauer, Gottfried H. [Institute of Physics, Carl von Ossietzky University Oldenburg, D-26111 Oldenburg (Germany)

    2011-07-01

    Fluorescence collectors (FCs) provide the option for concentration and simultaneous spectral selection of solar photons of direct or diffuse light. The energetic and commercial benefit of these systems depend on the yield of the conversion of solar photons into luminescence photons and on the efficiency of their respective conductance to the edges of the FC where they are coupled into appropriate solar cells. For the characterization of the performance of FCs and the identification of losses, we have performed angle and spectrally resolved measurements of fluorescence photons from FC with two different types of optical designs, a PMMA substrate with homogeneous depth dependent dye concentration and a novel type of FC, which consist of a transparent substrate with a thin overlayer containing the absorbing and emitting dye. We have recorded the edge fluorescence when illuminating the entire FC surface laterally homogeneously, as well as for slit-like excitation on the front surface with variation of the distance of the illuminated slit from the edge. We compare the experimental fluorescence results with a 2-dimensional ray-tracing approach and verify the spectral and angle dependent edge emission. Moreover we illuminate the FC with long wavelength photons which are not absorbed and conclude, again from angle dependent and spectrally resolved edge emission, on scattering losses at surfaces and in the bulk.

  7. Spectrally resolved pressure dependence measurements of air fluorescence emission with AIRFLY

    International Nuclear Information System (INIS)

    Ave, M.; Bohacova, M.; Buonomo, B.; Busca, N.; Cazon, L.; Chemerisov, S.D.; Conde, M.E.; Crowell, R.A.; Di Carlo, P.; Di Giulio, C.; Doubrava, M.; Esposito, A.; Facal, P.; Franchini, F.J.; Hoerandel, J.; Hrabovsky, M.; Iarlori, M.; Kasprzyk, T.E.; Keilhauer, B.; Klages, H.

    2008-01-01

    The knowledge of the fluorescence emission as a function of atmospheric parameters is essential for the detection of extensive air showers with the fluorescence technique. In this paper, we summarize AIRFLY published measurements of the pressure dependence of the fluorescence yield. The spectral distribution of the fluorescent light between 280 and 429 nm has been measured with high resolution. Relative intensities of 34 spectral lines have been determined. The pressure dependence of 25 lines was measured in terms of quenching reference pressures p λ ' in air. This set of AIRFLY measurements yields the most comprehensive parametrization of the pressure dependence of the fluorescent spectrum.

  8. Characterization of type I, II, III, IV, and V collagens by time-resolved laser-induced fluorescence spectroscopy

    Science.gov (United States)

    Marcu, Laura; Cohen, David; Maarek, Jean-Michel I.; Grundfest, Warren S.

    2000-04-01

    The relative proportions of genetically distinct collagen types in connective tissues vary with tissue type and change during disease progression, development, wound healing, aging. This study aims to 1) characterize the spectro- temporal fluorescence emission of fiber different types of collagen and 2) assess the ability of time-resolved laser- induced fluorescence spectroscopy to distinguish between collagen types. Fluorescence emission of commercially available purified samples was induced with nitrogen laser excitation pulses and detected with a MCP-PMT connected to a digital storage oscilloscope. The recorded time-resolved emission spectra displayed distinct fluorescence emission characteristics for each collagen type. The time domain information complemented the spectral domain intensity data for improved discrimination between different collagen types. Our results reveal that analysis of the fluorescence emission can be used to characterize different species of collagen. Also, the results suggest that time-resolved spectroscopy can be used for monitoring of connective tissue matrix composition changes due to various pathological and non-pathological conditions.

  9. Fast intramolecular electron transfer and dual fluorescence. Configurational change of the amino nitrogen (pyramidal→planar)

    International Nuclear Information System (INIS)

    Haar, Th. von der; Hebecker, A.; Il'Ichev, Yu.; Kuehnle, W.; Zachariasse, K. A.

    1996-01-01

    The fast excited state intramolecular charge transfer (ICT) and dual fluorescence observed with several 4-aminobenzonitriles is discussed. It is shown that the magnitude of the energy gap between the two lowest excited states determines the occurrence or absence of ICT. The photophysical behavior of a series of four 4-aminobenzonitriles in which the amino nitrogen atom is part of a four- to seven-membered heterocyclic ring, P4C to P7C, is studied by using time-resolved fluorescence measurements. The ICT rate constant strongly decreases with decreasing ring size. With P4C in diethyl ether ICT does not occur. This is attributed to the increase of the amino nitrogen inversion barrier with decreasing ring size. The change of the amino nitrogen from pyramidal to planar is considered to be an important reaction coordinate. The photophysics of the 4-aminobenzonitriles is different from that of other ICT systems such as donor/acceptor-substituted stilbenes and 9,9'-bianthryl, which are governed by the charge distribution and macroscopic Coulombic interaction in their CT states

  10. Satellite-based emission constraint for nitrogen oxides: Capability and uncertainty

    Science.gov (United States)

    Lin, J.; McElroy, M. B.; Boersma, F.; Nielsen, C.; Zhao, Y.; Lei, Y.; Liu, Y.; Zhang, Q.; Liu, Z.; Liu, H.; Mao, J.; Zhuang, G.; Roozendael, M.; Martin, R.; Wang, P.; Spurr, R. J.; Sneep, M.; Stammes, P.; Clemer, K.; Irie, H.

    2013-12-01

    Vertical column densities (VCDs) of tropospheric nitrogen dioxide (NO2) retrieved from satellite remote sensing have been employed widely to constrain emissions of nitrogen oxides (NOx). A major strength of satellite-based emission constraint is analysis of emission trends and variability, while a crucial limitation is errors both in satellite NO2 data and in model simulations relating NOx emissions to NO2 columns. Through a series of studies, we have explored these aspects over China. We separate anthropogenic from natural sources of NOx by exploiting their different seasonality. We infer trends of NOx emissions in recent years and effects of a variety of socioeconomic events at different spatiotemporal scales including the general economic growth, global financial crisis, Chinese New Year, and Beijing Olympics. We further investigate the impact of growing NOx emissions on particulate matter (PM) pollution in China. As part of recent developments, we identify and correct errors in both satellite NO2 retrieval and model simulation that ultimately affect NOx emission constraint. We improve the treatments of aerosol optical effects, clouds and surface reflectance in the NO2 retrieval process, using as reference ground-based MAX-DOAS measurements to evaluate the improved retrieval results. We analyze the sensitivity of simulated NO2 to errors in the model representation of major meteorological and chemical processes with a subsequent correction of model bias. Future studies will implement these improvements to re-constrain NOx emissions.

  11. Dual-emissive quantum dots for multispectral intraoperative fluorescence imaging.

    Science.gov (United States)

    Chin, Patrick T K; Buckle, Tessa; Aguirre de Miguel, Arantxa; Meskers, Stefan C J; Janssen, René A J; van Leeuwen, Fijs W B

    2010-09-01

    Fluorescence molecular imaging is rapidly increasing its popularity in image guided surgery applications. To help develop its full surgical potential it remains a challenge to generate dual-emissive imaging agents that allow for combined visible assessment and sensitive camera based imaging. To this end, we now describe multispectral InP/ZnS quantum dots (QDs) that exhibit a bright visible green/yellow exciton emission combined with a long-lived far red defect emission. The intensity of the latter emission was enhanced by X-ray irradiation and allows for: 1) inverted QD density dependent defect emission intensity, showing improved efficacies at lower QD densities, and 2) detection without direct illumination and interference from autofluorescence. Copyright 2010 Elsevier Ltd. All rights reserved.

  12. DNA abasic site-selective enhancement of sanguinarine fluorescence with a large emission shift.

    Directory of Open Access Journals (Sweden)

    Fei Wu

    Full Text Available Small molecules that can specifically bind to a DNA abasic site (AP site have received much attention due to their importance in DNA lesion identification, drug discovery, and sensor design. Herein, the AP site binding behavior of sanguinarine (SG, a natural alkaloid, was investigated. In aqueous solution, SG has a short-wavelength alkanolamine emission band and a long-wavelength iminium emission band. At pH 8.3, SG experiences a fluorescence quenching for both bands upon binding to fully matched DNAs without the AP site, while the presence of the AP site induces a strong SG binding and the observed fluorescence enhancement for the iminium band are highly dependent on the nucleobases flanking the AP site, while the alkanolamine band is always quenched. The bases opposite the AP site also exert some modifications on the SG's emission behavior. It was found that the observed quenching for DNAs with Gs and Cs flanking the AP site is most likely caused by electron transfer between the AP site-bound excited-state SG and the nearby Gs. However, the flanking As and Ts that are not easily oxidized favor the enhanced emission. This AP site-selective enhancement of SG fluorescence accompanies a band conversion in the dominate emission from the alkanolamine to iminium band thus with a large emission shift of about 170 nm. Absorption spectra, steady-state and transient-state fluorescence, DNA melting, and electrolyte experiments confirm that the AP site binding of SG occurs and the stacking interaction with the nearby base pairs is likely to prevent the converted SG iminium form from contacting with water that is thus emissive when the AP site neighbors are bases other than guanines. We expect that this fluorophore would be developed as a promising AP site binder having a large emission shift.

  13. Enhancement of electron field emission of vertically aligned carbon nanotubes by nitrogen plasma treatment

    Energy Technology Data Exchange (ETDEWEB)

    Wang, B.B. [College of Chemistry and Chemical Engineering, Chongqing University of Technology, 69 Hongguang Rd, Lijiatuo, Banan District, Chongqing 400054 (China); Plasma Nanoscience Centre Australia (PNCA), CSIRO Materials Science and Engineering, P.O. Box 218, Lindfield, NSW 2070 (Australia); Cheng, Q.J. [Plasma Nanoscience Centre Australia (PNCA), CSIRO Materials Science and Engineering, P.O. Box 218, Lindfield, NSW 2070 (Australia); Plasma Nanoscience, School of Physics, University of Sydney, Sydney, NSW 2006 (Australia); Chen, X. [College of Materials Science and Engineering, Chongqing University, Chongqing 400044 (China); Ostrikov, K., E-mail: kostya.ostrikov@csiro.au [Plasma Nanoscience Centre Australia (PNCA), CSIRO Materials Science and Engineering, P.O. Box 218, Lindfield, NSW 2070 (Australia); Plasma Nanoscience, School of Physics, University of Sydney, Sydney, NSW 2006 (Australia)

    2011-09-22

    Highlights: > A new and custom-designed bias-enhanced hot-filament chemical vapor deposition system is developed to synthesize vertically aligned carbon nanotubes. > The carbon nanotubes are later treated with nitrogen plasmas. > The electron field emission characteristics of the carbon nanotubes are significantly improved after the nitrogen plasma treatment. > A new physical mechanism is proposed to interpret the improvement of the field emission characteristics. - Abstract: The electron field emission (EFE) characteristics from vertically aligned carbon nanotubes (VACNTs) without and with treatment by the nitrogen plasma are investigated. The VACNTs with the plasma treatment showed a significant improvement in the EFE property compared to the untreated VACNTs. The morphological, structural, and compositional properties of the VACNTs are extensively examined by scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, and energy dispersive X-ray spectroscopy. It is shown that the significant EFE improvement of the VACNTs after the nitrogen plasma treatment is closely related to the variation of the morphological and structural properties of the VACNTs. The high current density (299.6 {mu}A/cm{sup 2}) achieved at a low applied field (3.50 V/{mu}m) suggests that the VACNTs after nitrogen plasma treatment can serve as effective electron field emission sources for numerous applications.

  14. Enhancement of electron field emission of vertically aligned carbon nanotubes by nitrogen plasma treatment

    International Nuclear Information System (INIS)

    Wang, B.B.; Cheng, Q.J.; Chen, X.; Ostrikov, K.

    2011-01-01

    Highlights: → A new and custom-designed bias-enhanced hot-filament chemical vapor deposition system is developed to synthesize vertically aligned carbon nanotubes. → The carbon nanotubes are later treated with nitrogen plasmas. → The electron field emission characteristics of the carbon nanotubes are significantly improved after the nitrogen plasma treatment. → A new physical mechanism is proposed to interpret the improvement of the field emission characteristics. - Abstract: The electron field emission (EFE) characteristics from vertically aligned carbon nanotubes (VACNTs) without and with treatment by the nitrogen plasma are investigated. The VACNTs with the plasma treatment showed a significant improvement in the EFE property compared to the untreated VACNTs. The morphological, structural, and compositional properties of the VACNTs are extensively examined by scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, and energy dispersive X-ray spectroscopy. It is shown that the significant EFE improvement of the VACNTs after the nitrogen plasma treatment is closely related to the variation of the morphological and structural properties of the VACNTs. The high current density (299.6 μA/cm 2 ) achieved at a low applied field (3.50 V/μm) suggests that the VACNTs after nitrogen plasma treatment can serve as effective electron field emission sources for numerous applications.

  15. Numerical modeling of nitrogen oxide emission and experimental verification

    Directory of Open Access Journals (Sweden)

    Szecowka Lech

    2003-12-01

    Full Text Available The results of nitrogen reduction in combustion process with application of primary method are presented in paper. The reduction of NOx emission, by the recirculation of combustion gasses, staging of fuel and of air was investigated, and than the reduction of NOx emission by simultaneous usage of the mentioned above primary method with pulsatory disturbances.The investigations contain numerical modeling of NOx reduction and experimental verification of obtained numerical calculation results.

  16. Three-dimensional super-resolution imaging for fluorescence emission difference microscopy

    Energy Technology Data Exchange (ETDEWEB)

    You, Shangting; Kuang, Cuifang, E-mail: cfkuang@zju.edu.cn; Li, Shuai; Liu, Xu; Ding, Zhihua [State key laboratory of modern optical instrumentations, Zhejiang University, Hangzhou 310027 (China)

    2015-08-15

    We propose a method theoretically to break the diffraction limit and to improve the resolution in all three dimensions for fluorescence emission difference microscopy. We produce two kinds of hollow focal spot by phase modulation. By incoherent superposition, these two kinds of focal spot yield a 3D hollow focal spot. The optimal proportion of these two kinds of spot is given in the paper. By employing 3D hollow focal spot, super-resolution image can be yielded by means of fluorescence emission difference microscopy, with resolution enhanced both laterally and axially. According to computation result, size of point spread function of three-dimensional super-resolution imaging is reduced by about 40% in all three spatial directions with respect to confocal imaging.

  17. Chlorophyll fluorescence response to water and nitrogen deficit

    Science.gov (United States)

    Cendrero Mateo, Maria del Pilar

    The increasing food demand as well as the need to predict the impact of warming climate on vegetation makes it critical to find the best tools to assess crop production and carbon dioxide (CO2) exchange between the land and atmosphere. Photosynthesis is a good indicator of crop production and CO2 exchange. Chlorophyll fluorescence (ChF) is directly related to photosynthesis. ChF can be measured at leaf-scale using active techniques and at field-scales using passive techniques. The measurement principles of both techniques are different. In this study, three overarching questions about ChF were addressed: Q1) How water, nutrient and ambient light conditions determine the relationships between photosynthesis and ChF? Which is the optimum irradiance level for detecting water and nutrient deficit conditions with ChF? ; Q2) which are the limits within which active and passive techniques are comparable?; and Q3) What is the seasonal relationship between photosynthesis and ChF when nitrogen is the limiting factor? To address these questions, two main experiments were conducted: Exp1) Concurrent photosynthesis and ChF light-response curves were measured in camelina and wheat plants growing under (i) intermediate-light and (ii) high-light conditions respectively. Plant stress was induced by (i) withdrawing water, and (ii) applying different nitrogen levels; and Exp2) coincident active and passive ChF measurements were made in a wheat field under different nitrogen treatments. The results indicated ChF has a direct relationship with photosynthesis when water or nitrogen drives the relationship. This study demonstrates that the light level at which plants were grown was optimum for detecting water and nutrient deficit with ChF. Also, the results showed that for leaf-average-values, active measurements can be used to better understand the daily and seasonal behavior of passive ChF. Further, the seasonal relation between photosynthesis and ChF with nitrogen stress was not a

  18. Emissions of carbon, nitrogen, and sulfur from biomass burning in Nigeria

    International Nuclear Information System (INIS)

    Akeredolu, F.; Isichei, A.O.

    1991-01-01

    The atmospheric implications of the effects of burning of vegetation in Nigeria are discussed. The following topics are explored: the extent of biomass burning by geographical area; estimates of emission rates of carbon, nitrogen and sulfur; and the impact on biogeochemical cycling of elements. The results suggest that biomass burning generates a measurable impact on the cycling of carbon and nitrogen

  19. Solid-immersion fluorescence microscopy with increased emission and super resolution

    Energy Technology Data Exchange (ETDEWEB)

    Liau, Z. L.; Porter, J. M. [Lincoln Laboratory, Massachusetts Institute of Technology, Lexington, Massachusetts 02420 (United States); Liau, A. A.; Chen, J. J. [Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Salmon, W. C. [Whitehead Institute, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Sheu, S. S. [Department of Medicine, Jefferson Medical College, Philadelphia, Pennsylvania 19107 (United States)

    2015-01-07

    We investigate solid-immersion fluorescence microscopy suitable for super-resolution nanotechnology and biological imaging, and have observed limit of resolution as small as 15 nm with microspheres, mitochondria, and chromatin fibers. We have further observed that fluorescence efficiency increases with excitation power density, implicating appreciable stimulated emission and increased resolution. We discuss potential advantages of the solid-immersion microscopy, including combined use with previously established super-resolution techniques for reaching deeper beyond the conventional diffraction limit.

  20. Distinguishing nitrogen fertilization levels in field corn (Zea mays L.) with actively induced fluorescence and passive reflectance measurements

    International Nuclear Information System (INIS)

    McMurtrey, J.E. III; Chappelle, E.W.; Kim, M.S.; Meisinger, J.J.; Corp, L.A

    1994-01-01

    Laser-induced fluorescence (LIF) is an active sensing technique capable of capturing immediate and specific indications of changes in plant physiology and metabolism as they relate to the concentration and photosynthetic activity of the plant pigments. Reflectance is a passive sensing technique that can capture differences in the concentration of the primary plant pigments. Fluorescence and reflectance were compared for their ability to measure levels of plant stress that are of agronomic importance in corn (Zea mays L.) crops. Laboratory LIF and reflectance spectra were made on excised leaves from field grown corn. Changes in the visible region of the spectrum were compared between groups of plants fertilized with seven different levels of nitrogen (N) fertilization. A pulsed nitrogen laser emitting photons at a wavelength of 337 nm was used as a fluorescence excitation source. Differences in maximum intensity of fluorescence occurred at 440 nm, 525 nm, 685 nm, and 740 nm. Significant separations were found between levels of N fertilization at several LIF wavelength ratios. Several reflectance algorithms also produced significant separations between certain levels of N fertilization

  1. Polarization Multiplexing of Fluorescent Emission Using Multiresonant Plasmonic Antennas.

    Science.gov (United States)

    De Leo, Eva; Cocina, Ario; Tiwari, Preksha; Poulikakos, Lisa V; Marqués-Gallego, Patricia; le Feber, Boris; Norris, David J; Prins, Ferry

    2017-12-26

    Combining the ability to localize electromagnetic fields at the nanoscale with a directional response, plasmonic antennas offer an effective strategy to shape the far-field pattern of coupled emitters. Here, we introduce a family of directional multiresonant antennas that allows for polarization-resolved spectral identification of fluorescent emission. The geometry consists of a central aperture surrounded by concentric polygonal corrugations. By varying the periodicity of each axis of the polygon individually, this structure can support multiple resonances that provide independent control over emission directionality for multiple wavelengths. Moreover, since each resonant wavelength is directly mapped to a specific polarization orientation, spectral information can be encoded in the polarization state of the out-scattered beam. To demonstrate the potential of such structures in enabling simplified detection schemes and additional functionalities in sensing and imaging applications, we use the central subwavelength aperture as a built-in nanocuvette and manipulate the fluorescent response of colloidal-quantum-dot emitters coupled to the multiresonant antenna.

  2. Emissions of nitrogen oxides and particulates of diesel vehicles

    NARCIS (Netherlands)

    Kadijk, G.; Ligterink, N.E.; Mensch, P. van; Spreen, J.S.; Vermeulen, R.J.; Vonk, W.A.

    2015-01-01

    In real-world conditions, modern Euro VI heavy-duty vehicles produce an average of ten times less nitrogen oxide (NOx)emissions than previous generations of Euro IV and Euro V heavy-duty vehicles. However, Euro 6 passenger cars and light commercial vehicles present an entirely different picture

  3. Soil emissions of gaseous reactive nitrogen from North American arid lands: an overlooked source.

    Science.gov (United States)

    Sparks, J. P.; McCalley, C. K.; Strahm, B. D.

    2008-12-01

    The biosphere-atmosphere exchange and transformation of nitrogen has important ramifications for both terrestrial biogeochemistry and atmospheric chemistry. Several important mechanisms within this process (e.g., photochemistry, nitrogen deposition, aerosol formation) are strongly influenced by the emission of reactive nitrogen compounds from the Earth's surface. Therefore, a quantification of emission sources is a high priority for future conceptual understanding. One source largely overlooked in most global treatments are the soil emissions from arid and semi-arid landscapes worldwide. Approximately 35-40% of global terrestrial land cover is aridland and emission of reactive nitrogen from soils in these regions has the potential to strongly influence both regional and global biogeochemistry. Here we present estimates of soil emission of oxidized (NO, total NOy including NO2 and HONO) and reduced (NH3) forms of reactive nitrogen from two North American arid regions: the Mojave Desert and the Colorado Plateau. Soil fluxes in these regions are highly dependent on soil moisture conditions. Soil moisture is largely driven by pulsed rain events with fluxes increasing 20-40 fold after a rain event. Using field measurements made across seasons under an array of moisture conditions, precipitation records, and spatially explicit cover type information we have estimated annual estimates for the Mojave Desert (1.5 ± 0.7 g N ha-1 yr-1), the shale derived (1.4 ± 0.9 g N ha-1 yr-1), and sandy soil derived (2.8 ± 1.2 g N ha-1 yr-1) regions of the Colorado Plateau. The chemical composition of soil emissions varies significantly both with season and soil moisture content. Emissions from dry soils tend to be dominated by ammonia and forms of NOy other than NO. In contrast, NO becomes a dominant portion of the flux post rain events (~30% of the total flux). This variability in chemical form has significant implications for the tropospheric fate of the emitted N. NO and other

  4. 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

  5. Meta-analysis assessing potential of steady-state chlorophyll fluorescence for remote sensing detection of plant water, temperature and nitrogen stress

    Czech Academy of Sciences Publication Activity Database

    Ač, Alexander; Malenovský, Z.; Olejníčková, Julie; Gallé, A.; Rascher, U.; Mohammed, G.

    2015-01-01

    Roč. 168, oct (2015), s. 420-436 ISSN 0034-4257 R&D Projects: GA MŠk(CZ) LO1415 Institutional support: RVO:67179843 Keywords : steady-state chlorophyll fluorescence * passive sun-induced fluorescence * active laser-induced fluorescence * photosynthesis * stress * water * temperature * nitrogen * random-effects meta-analysis * FLEX satellite mission Subject RIV: EH - Ecology, Behaviour Impact factor: 5.881, year: 2015

  6. Efficient synthesis of highly fluorescent nitrogen-doped carbon dots for cell imaging using unripe fruit extract of Prunus mume

    International Nuclear Information System (INIS)

    Atchudan, Raji; Edison, Thomas Nesakumar Jebakumar Immanuel; Sethuraman, Mathur Gopalakrishnan; Lee, Yong Rok

    2016-01-01

    Graphical abstract: The green synthesis of highly fluorescent N-CDs was achieved using the extract of unripe P. mume fruit as a carbon precursor by a one-pot simple hydrothermal-carbonization method. The resulting N-CDs were used as a staining agent for the fluorescence imaging of MDA-MB-231 cells. Display Omitted - Highlights: • The green synthesis of highly fluorescent N-CDs using the extract of unripe P. mume. • The N-CDs were synthesized by one-pot hydrothermal-carbonization method. • This method of synthesis is a simple, cost effective and eco-friendly route. • N-CDs will be a good alternative for fluorescent dyes and SQDs for bio-applications. - Abstract: Highly fluorescent nitrogen-doped carbon dots (N-CDs) were synthesized using the extract of unripe Prunus mume (P. mume) fruit by a simple one step hydrothermal-carbonization method. The N-CDs were synthesized at different pH ranges, 2.3, 5, 7, and 9. The pH of the P. mume extract was adjusted using an aqueous ammonia solution (25%). The optical properties of N-CDs were examined by UV–vis and fluorescence spectroscopy. The N-CDs synthesized at pH 9 emitted high fluorescence intensity compared to other obtained N-CDs. The N-CDs synthesized at pH 9 was further characterized by high resolution transmission electron microscopy (HR-TEM), X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and Fourier transform-infra red (FT-IR) spectroscopy. HR-TEM showed that the average size of the synthesized N-CDs was approximately 9 nm and the interlayer distance was 0.21 nm, which was validated by XRD. The graphitic nature of the synthesized N-CDs were confirmed by Raman spectroscopy. XPS and FT-IR spectroscopy confirmed the doping of the nitrogen moiety over the synthesized CDs. The synthesized nitrogen doped CDs (N-CDs) were low toxicity and were used as a staining probe for fluorescence cell imaging.

  7. Efficient synthesis of highly fluorescent nitrogen-doped carbon dots for cell imaging using unripe fruit extract of Prunus mume

    Energy Technology Data Exchange (ETDEWEB)

    Atchudan, Raji; Edison, Thomas Nesakumar Jebakumar Immanuel [School of Chemical Engineering, Yeungnam University, Gyeongsan 38541 (Korea, Republic of); Sethuraman, Mathur Gopalakrishnan, E-mail: mgsethu@gmail.com [Department of Chemistry, Gandhigram Rural Institute-Deemed University, Gandhigram 624 302, Tamilnadu (India); Lee, Yong Rok, E-mail: yrlee@yu.ac.kr [School of Chemical Engineering, Yeungnam University, Gyeongsan 38541 (Korea, Republic of)

    2016-10-30

    Graphical abstract: The green synthesis of highly fluorescent N-CDs was achieved using the extract of unripe P. mume fruit as a carbon precursor by a one-pot simple hydrothermal-carbonization method. The resulting N-CDs were used as a staining agent for the fluorescence imaging of MDA-MB-231 cells. Display Omitted - Highlights: • The green synthesis of highly fluorescent N-CDs using the extract of unripe P. mume. • The N-CDs were synthesized by one-pot hydrothermal-carbonization method. • This method of synthesis is a simple, cost effective and eco-friendly route. • N-CDs will be a good alternative for fluorescent dyes and SQDs for bio-applications. - Abstract: Highly fluorescent nitrogen-doped carbon dots (N-CDs) were synthesized using the extract of unripe Prunus mume (P. mume) fruit by a simple one step hydrothermal-carbonization method. The N-CDs were synthesized at different pH ranges, 2.3, 5, 7, and 9. The pH of the P. mume extract was adjusted using an aqueous ammonia solution (25%). The optical properties of N-CDs were examined by UV–vis and fluorescence spectroscopy. The N-CDs synthesized at pH 9 emitted high fluorescence intensity compared to other obtained N-CDs. The N-CDs synthesized at pH 9 was further characterized by high resolution transmission electron microscopy (HR-TEM), X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and Fourier transform-infra red (FT-IR) spectroscopy. HR-TEM showed that the average size of the synthesized N-CDs was approximately 9 nm and the interlayer distance was 0.21 nm, which was validated by XRD. The graphitic nature of the synthesized N-CDs were confirmed by Raman spectroscopy. XPS and FT-IR spectroscopy confirmed the doping of the nitrogen moiety over the synthesized CDs. The synthesized nitrogen doped CDs (N-CDs) were low toxicity and were used as a staining probe for fluorescence cell imaging.

  8. Quenched carbonaceous composite - Fluorescence spectrum compared to the extended red emission observed in reflection nebulae

    Science.gov (United States)

    Sakata, Akira; Wada, Setsuko; Narisawa, Takatoshi; Asano, Yoichi; Iijima, Yutaka; Onaka, Takashi; Tokunaga, Alan T.

    1992-01-01

    The photoluminescence (fluorescence) of a film of the laboratory-synthesized quenched carbonaceous composite (filmy QCC) is shown to have a single broad emission feature with a peak wavelength that varies from 670 to 725 nm, and coincides with that of the extended red emission observed in reflection nebulae. The rapid decay of the filmy QCC red fluorescence in air and of the stable blue fluorescence of the filmy QCC dissolved in liquid Freon suggests that the red fluorescence originates from the interaction of active chemical species and aromatic components in the filmy QCC. A material similar in nature to that of the filmy QCC may be a major component of interstellar dust.

  9. Exploring a suitable nitrogen fertilizer rate to reduce greenhouse gas emissions and ensure rice yields in paddy fields

    Energy Technology Data Exchange (ETDEWEB)

    Zhong, Yiming; Wang, Xiaopeng; Yang, Jingping, E-mail: jpyang@zju.edu.cn; Zhao, Xing; Ye, Xinyi

    2016-09-15

    The application rate of nitrogen fertilizer was believed to dramatically influence greenhouse gas (GHG) emissions from paddy fields. Thus, providing a suitable nitrogen fertilization rate to ensure rice yields, reducing GHG emissions and exploring emission behavior are important issues for field management. In this paper, a two year experiment with six rates (0, 75, 150, 225, 300, 375 kg N/ha) of nitrogen fertilizer application was designed to examine GHG emissions by measuring carbon dioxide (CO{sub 2}), methane (CH{sub 4}), nitrous oxide (N{sub 2}O) flux and their cumulative global warming potential (GWP) from paddy fields in Hangzhou, Zhejiang in 2013 and 2014. The results indicated that the GWP and rice yields increased with an increasing application rate of nitrogen fertilizer. Emission peaks of CH{sub 4} mainly appeared at the vegetative phase, and emission peaks of CO{sub 2}, and N{sub 2}O mainly appeared at reproductive phase of rice growth. The CO{sub 2} flux was significantly correlated with soil temperature, while the CH{sub 4} flux was influenced by logging water remaining period and N{sub 2}O flux was significantly associated with nitrogen application rates. This study showed that 225 kg N/ha was a suitable nitrogen fertilizer rate to minimize GHG emissions with low yield-scaled emissions of 3.69 (in 2013) and 2.23 (in 2014) kg CO{sub 2}-eq/kg rice yield as well as to ensure rice yields remained at a relatively high level of 8.89 t/ha in paddy fields. - Highlights: • Exploiting co-benefits of rice yield and reduction of greenhouse gas emission. • Global warming potential and rice yield increased with nitrogen fertilizer rate up. • Emission peaks of CH{sub 4,} CO{sub 2} and N{sub 2}O appeared at vegetative and reproductive phase. • 225 kg N/ha rate benefits both rice yields and GWP reduction.

  10. Efficiency of an emissions payment system for nitrogen in sewage treatment plants - a case study.

    Science.gov (United States)

    Malmaeus, J Mikael; Ek, Mats; Åmand, Linda; Roth, Susanna; Baresel, Christian; Olshammar, Mikael

    2015-05-01

    An emissions payment system for nitrogen in Swedish sewage treatment plants (STPs) was evaluated using a semi-empirical approach. The system was based on a tariff levied on each unit of nitrogen emitted by STPs, and profitable measures to reduce nitrogen emissions were identified for twenty municipal STPs. This was done through direct involvement with the plant personnel and the results were scaled up to cover all treatment plants larger than 2000 person equivalents in the Swedish tributary areas of the Kattegat and the Baltic Proper. The sum of costs and nitrogen reductions were compared with an assumed command-and-control regulation requiring all STPs to obtain 80% total nitrogen reduction in their effluents. Costs for the latter case were estimated using a database containing standard estimates for reduction costs by six specified measures. For both cases a total reduction target of 3000 tonnes of nitrogen was set. We did not find that the emissions payment system was more efficient in terms of total reduction costs, although some practical and administrative advantages could be identified. Our results emphasize the need to evaluate the performance of policy instruments on a case-by-case basis since the theoretical efficiency is not always reflected in practice. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Anthropogenic emissions of oxidized sulfur and nitrogen into the atmosphere of the former Soviet Union in 1985 and 1990

    Energy Technology Data Exchange (ETDEWEB)

    Ryaboshapko, A.G.; Brukhanov, P.A.; Gromov, S.A.; Proshina, Yu.V; Afinogenova, O.G. [Institute of Global Climate and Ecology, Moscow (Russian Federation)

    1996-09-01

    Anthropogenic emissions of oxidized sulfur and nitrogen over the former Soviet Union for 1985 and 1990 were calculated on the basis of a combination of `bottom-up` and `top-down` approaches. Sulfur dioxide emissions from combustion of hard coal, brown coal, oil products, natural gas, shale oil, peat, wood as well as from metallurgy, sulfuric acid production, and cement production were estimated. Nitrogen oxides emissions were considered separately for large power plants, small power plants, industrial boilers, residential combustion units, and for transport. The sulfur and nitrogen emissions were spatially distributed over the former Soviet Union with 1 x 1 degree resolution. Data on 721 point sources of sulfur dioxide emissions and on the 242 largest power stations as nitrogen oxides sources were used. The area sources of both sulfur dioxide and nitrogen oxides were distributed according to the population density separately for about 150 administrative units of the former Soviet Union. 63 refs., 19 tabs.

  12. Time-resolved laser-induced fluorescence system

    Science.gov (United States)

    Bautista, F. J.; De la Rosa, J.; Gallegos, F. J.

    2006-02-01

    Fluorescence methods are being used increasingly in the measurement of species concentrations in gases, liquids and solids. Laser induced fluorescence is spontaneous emission from atoms or molecules that have been excited by laser radiation. Here we present a time resolved fluorescence instrument that consists of a 5 μJ Nitrogen laser (337.1 nm), a sample holder, a quartz optical fiber, a spectrometer, a PMT and a PC that allows the measurement of visible fluorescence spectra (350-750 nm). Time response of the system is approximately 5 ns. The instrument has been used in the measurement of colored bond paper, antifreeze, diesel, cochineal pigment and malignant tissues. The data acquisition was achieved through computer control of a digital oscilloscope (using General Purpose Interface Bus GPIB) and the spectrometer via serial (RS232). The instrument software provides a graphic interface that lets make some data acquisition tasks like finding fluorescence spectra, and fluorescence lifetimes. The software was developed using the Lab-View 6i graphic programming package and can be easily managed in order to add more functions to it.

  13. New levy on nitrogen oxide emissions: First 'refundable' pollution charge

    International Nuclear Information System (INIS)

    Andersson, Sus; Hanneberg, P.

    1991-01-01

    A new law imposing a charge on nitrogen oxide emissions from combustion installations will soon be coming into force in Sweden. The money generated by the charge will not stay in the exchequer, however, but will be repaid to the plants concerned in proportion to the amount of useful energy they produce. This will be the first environment levy in Sweden to be based on measurements of actual emissions. Emissions of sulphur and carbon dioxide are already taxed. These taxes, unlike other environmental charges, not only have an incentive function, but are also a source of income for the state

  14. Preliminary Results of Nuclear Fluorescence Imaging of Alpha and Beta Emitting Sources

    International Nuclear Information System (INIS)

    Feener, Jessica S.; Charlton, William S.

    2013-06-01

    The preliminary results from a series of nuclear fluorescence imaging experiments using a variety of radioactive sources and shielding are given. These experiments were done as part of a proof of concept to determine if nuclear fluorescence imaging could be used as a safeguards measurements tool or for nuclear warhead verification for nuclear arms control treaties such as the New Strategic Arms Reduction Treaty and the Fissile Material Cut-Off Treaty. An off-the-shelf Princeton Instruments charged coupled device camera system was used to image the emission of fluorescence photons from the de-excitation of nitrogen molecules in air that have been excited by ionizing radiation. The fluorescence emissions are primarily in the near ultraviolet range; between the wavelengths of 300 and 400 nm. Fluorescent imaging techniques are currently being investigated in a number of applications. A French research team has successfully demonstrated this concept for remote imaging of alpha contamination. It has also been shown that the phenomenon can be seen through translucent materials and that alpha radiation can be seen in the presence of large gamma backgrounds. Additionally, fluorescence telescopes and satellites utilize the de-excitation of nitrogen molecules to observe cosmic ray showers in the atmosphere. In cosmic ray shower detection, electrons are the main contributor to the excitation of the of nitrogen molecules in air. The experiments presented in this paper were designed to determine if the imaging system could observe beta emitting sources, differentiate between beta emitters and alpha emitting materials such as uranium oxide and uranium metal, and to further investigate the phenomenon through translucent and non-translucent materials. The initial results show that differentiation can be made between beta and alpha emitting sources and that the device can observe the phenomenon through very thin non-transparent material. Additionally, information is given on the

  15. The role of power plant atmospheric emissions in the deposition of nitrogen to the Chesapeake Bay

    International Nuclear Information System (INIS)

    Miller, P.E.

    1994-01-01

    The Maryland Power Plant Research Program (PPRP) has sponsored research on several aspects of atmospheric nitrogen emissions, source attribution, deposition estimation and impact assessment since the mid-eighties. The results of these studies will be presented and discussed in the context of power plant emissions control impact on nitrogen loadings to the Chesapeake Bay and watershed. Information needs with respect to power plant contribution and emission control policy will be identified and discussed from the perspective of PPRP

  16. Chip-integrated plasmonic cavity-enhanced single nitrogen-vacancy center emission

    DEFF Research Database (Denmark)

    Siampour, Hamidreza; Kumar, Shailesh; Bozhevolnyi, Sergey I.

    2017-01-01

    High temporal stability and spin dynamics of individual nitrogen-vacancy (NV) centers in diamond crystals make them one of the most promising quantum emitters operating at room temperature. We demonstrate a chip-integrated cavity-coupled emission into propagating surface plasmon polariton (SPP...

  17. Modulation of nitrogen vacancy charge state and fluorescence in nanodiamonds using electrochemical potential.

    Science.gov (United States)

    Karaveli, Sinan; Gaathon, Ophir; Wolcott, Abraham; Sakakibara, Reyu; Shemesh, Or A; Peterka, Darcy S; Boyden, Edward S; Owen, Jonathan S; Yuste, Rafael; Englund, Dirk

    2016-04-12

    The negatively charged nitrogen vacancy (NV(-)) center in diamond has attracted strong interest for a wide range of sensing and quantum information processing applications. To this end, recent work has focused on controlling the NV charge state, whose stability strongly depends on its electrostatic environment. Here, we demonstrate that the charge state and fluorescence dynamics of single NV centers in nanodiamonds with different surface terminations can be controlled by an externally applied potential difference in an electrochemical cell. The voltage dependence of the NV charge state can be used to stabilize the NV(-) state for spin-based sensing protocols and provides a method of charge state-dependent fluorescence sensing of electrochemical potentials. We detect clear NV fluorescence modulation for voltage changes down to 100 mV, with a single NV and down to 20 mV with multiple NV centers in a wide-field imaging mode. These results suggest that NV centers in nanodiamonds could enable parallel optical detection of biologically relevant electrochemical potentials.

  18. Modulation of nitrogen vacancy charge state and fluorescence in nanodiamonds using electrochemical potential

    Science.gov (United States)

    Karaveli, Sinan; Gaathon, Ophir; Wolcott, Abraham; Sakakibara, Reyu; Shemesh, Or A.; Peterka, Darcy S.; Boyden, Edward S.; Owen, Jonathan S.; Yuste, Rafael; Englund, Dirk

    2016-04-01

    The negatively charged nitrogen vacancy (NV-) center in diamond has attracted strong interest for a wide range of sensing and quantum information processing applications. To this end, recent work has focused on controlling the NV charge state, whose stability strongly depends on its electrostatic environment. Here, we demonstrate that the charge state and fluorescence dynamics of single NV centers in nanodiamonds with different surface terminations can be controlled by an externally applied potential difference in an electrochemical cell. The voltage dependence of the NV charge state can be used to stabilize the NV- state for spin-based sensing protocols and provides a method of charge state-dependent fluorescence sensing of electrochemical potentials. We detect clear NV fluorescence modulation for voltage changes down to 100 mV, with a single NV and down to 20 mV with multiple NV centers in a wide-field imaging mode. These results suggest that NV centers in nanodiamonds could enable parallel optical detection of biologically relevant electrochemical potentials.

  19. Influence of carbon dioxide content in the biogas to nitrogen oxides emissions

    Directory of Open Access Journals (Sweden)

    Živković Marija A.

    2010-01-01

    Full Text Available Fuels derived from biomass are an alternative solution for the fossil fuel shortage. Usually this kind of fuels is called low calorific value fuels, due to the large proportion of inert components in their composition. The most common is carbon dioxide, and its proportion in biogas can be different, from 10 up to 40%, or even more. The presence of inert component in the composition of biogas causes the problems that are related with flame blow off limits. One of the possibilities for efficient combustion of biogas is the combustion in swirling flow including a pilot burner, aimed to expand the borders of stable combustion. This paper presents an analysis of the influence of the carbon dioxide content to the nitrogen oxides emissions. Laboratory biogas was used with different content of CO2 (10, 20, 30 and 40%. Investigation was carried out for different nominal powers, coefficients of excess air and carbon dioxide content. With increasing content of carbon dioxide, emission of nitrogen oxides was reduced, and this trend was the same throughout the whole range of excess air, carried out through measurements. Still, the influence of carbon dioxide content is significantly less than the influence of excess air. The coefficient of excess air greatly affects the production of radicals which are essential for the formation of nitrogen oxides, O, OH and CH. Also, the results show that the nominal power has no impact on the emission of nitrogen oxides.

  20. 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)

  1. Emission of nitrogen oxides from small biomass-fired grate boilers - a literature survey

    International Nuclear Information System (INIS)

    Olsson, Daniel

    1999-05-01

    A literature study has been carried out to find mechanisms for control of nitrogen oxide emissions from small-scale biomass fired combustion devices. The underlying nitrogen chemistry has been studied. Three paths of nitrogen oxide formation has been identified: 1. Thermal NO x , 2, Prompt NO x , and, 3. Fuel NO x . Out of these three mechanisms only fuel NO x is of interest, and the others are neglected at the temperature level concerned. The results from this study have been used to identify limitations and possibilities for NO x and CO abatement. A beacon has been to find efficient methods for NO x abatement at the same time as complete burn-out of the fuel is of greatest importance. The NO x abatement work of many of the Swedish manufacturers of small-scale combustion devices is described. This gives valuable insight in the practical possibilities and limitations in strive for low NOx emissions. From the literature and the contacts with manufacturers some factors of great importance for NO x emission control have been identified. These are: * The fuel (nitrogen content, shape, size, the height of the fuel layer and the tendency of the fuel to stick), * The stoichiometry in the volume above the fuel bed (should be 0.6 - 0.8), * The mixing of the gases above the fuel bed, * The mixing of tertiary air into the main gas flow, and * The thermal load of the combustion chamber (residence time). All the secondary measures studied but selective catalytic reduction have been rejected. Selective catalytic reduction could be a possible solution to the NO x emission problem if it is necessary to further lower the emissions from these small-scale biomass combustion devices despite the cost Project report from the program: Small scale combustion of biofuels. 22 refs, 30 figs, 4 tabs

  2. Parallel excitation-emission multiplexed fluorescence lifetime confocal microscopy for live cell imaging.

    Science.gov (United States)

    Zhao, Ming; Li, Yu; Peng, Leilei

    2014-05-05

    We present a novel excitation-emission multiplexed fluorescence lifetime microscopy (FLIM) method that surpasses current FLIM techniques in multiplexing capability. The method employs Fourier multiplexing to simultaneously acquire confocal fluorescence lifetime images of multiple excitation wavelength and emission color combinations at 44,000 pixels/sec. The system is built with low-cost CW laser sources and standard PMTs with versatile spectral configuration, which can be implemented as an add-on to commercial confocal microscopes. The Fourier lifetime confocal method allows fast multiplexed FLIM imaging, which makes it possible to monitor multiple biological processes in live cells. The low cost and compatibility with commercial systems could also make multiplexed FLIM more accessible to biological research community.

  3. Spatial distribution of fluorescent light emitted from neon and nitrogen excited by low energy electron beams

    International Nuclear Information System (INIS)

    Morozov, A.; Kruecken, R.; Ulrich, A.; Wieser, J.

    2006-01-01

    Side-view intensity profiles of fluorescent light were measured for neon and nitrogen excited with 12 keV electron beams at gas pressures from 250 to 1400 hPa. The intensity profiles were compared with theoretical profiles calculated using the CASINO program which performs Monte Carlo simulations of electron scattering. It was assumed that the spatial distribution of fluorescent intensity is directly proportional to the spatial distribution of energy loss by primary electrons. The comparison shows good correlation of experimental data and the results of numeric simulations

  4. Nanodiamond arrays on glass for quantification and fluorescence characterisation.

    Science.gov (United States)

    Heffernan, Ashleigh H; Greentree, Andrew D; Gibson, Brant C

    2017-08-23

    Quantifying the variation in emission properties of fluorescent nanodiamonds is important for developing their wide-ranging applicability. Directed self-assembly techniques show promise for positioning nanodiamonds precisely enabling such quantification. Here we show an approach for depositing nanodiamonds in pre-determined arrays which are used to gather statistical information about fluorescent lifetimes. The arrays were created via a layer of photoresist patterned with grids of apertures using electron beam lithography and then drop-cast with nanodiamonds. Electron microscopy revealed a 90% average deposition yield across 3,376 populated array sites, with an average of 20 nanodiamonds per site. Confocal microscopy, optimised for nitrogen vacancy fluorescence collection, revealed a broad distribution of fluorescent lifetimes in agreement with literature. This method for statistically quantifying fluorescent nanoparticles provides a step towards fabrication of hybrid photonic devices for applications from quantum cryptography to sensing.

  5. Fluorescence of Bacteria, Pollens, and Naturally Occurring Airborne Particles: Excitation/Emission Spectra

    National Research Council Canada - National Science Library

    Hill, Steven C; Mayo, Michael W; Chang, Richard K

    2009-01-01

    The fluorescence intensity as a function of excitation and emission wavelengths (EEM spectra) was measured for different species of bacteria, biochemical constituents of cells, pollens, and vegetation...

  6. Theoretical analysis of fluorescence signals in filamentation of femtosecond laser pulses in nitrogen molecular gas

    International Nuclear Information System (INIS)

    Arevalo, E.; Becker, A.

    2005-01-01

    We study numerically and analytically the role of the combined effect of self-focusing, geometrical focusing, and the plasma defocusing in the formation of the fluorescence signal during the filamentation of a Ti:sapphire laser pulse in nitrogen molecular gas. Results of numerical simulations are used to estimate the number of excited ions in the focal volume, which is proportional to the fluorescence signal. We find good agreement between the theoretical results and the experimental data, showing that such data can be used to get further insight into the effective focal volume during filamentation of femtosecond laser pulses in transparent media

  7. Improvement of LOD in Fluorescence Detection with Spectrally Nonuniform Background by Optimization of Emission Filtering.

    Science.gov (United States)

    Galievsky, Victor A; Stasheuski, Alexander S; Krylov, Sergey N

    2017-10-17

    The limit-of-detection (LOD) in analytical instruments with fluorescence detection can be improved by reducing noise of optical background. Efficiently reducing optical background noise in systems with spectrally nonuniform background requires complex optimization of an emission filter-the main element of spectral filtration. Here, we introduce a filter-optimization method, which utilizes an expression for the signal-to-noise ratio (SNR) as a function of (i) all noise components (dark, shot, and flicker), (ii) emission spectrum of the analyte, (iii) emission spectrum of the optical background, and (iv) transmittance spectrum of the emission filter. In essence, the noise components and the emission spectra are determined experimentally and substituted into the expression. This leaves a single variable-the transmittance spectrum of the filter-which is optimized numerically by maximizing SNR. Maximizing SNR provides an accurate way of filter optimization, while a previously used approach based on maximizing a signal-to-background ratio (SBR) is the approximation that can lead to much poorer LOD specifically in detection of fluorescently labeled biomolecules. The proposed filter-optimization method will be an indispensable tool for developing new and improving existing fluorescence-detection systems aiming at ultimately low LOD.

  8. Emission shaping in fluorescent proteins: role of electrostatics and π-stacking.

    Science.gov (United States)

    Park, Jae Woo; Rhee, Young Min

    2016-02-07

    For many decades, simulating the excited state properties of complex systems has been an intriguing but daunting task due to its high computational cost. Here, we apply molecular dynamics based techniques with interpolated potential energy surfaces toward calculating fluorescence spectra of the green fluorescent protein (GFP) and its variants in a statistically meaningful manner. With the GFP, we show that the diverse electrostatic tuning can shape the emission features in many different ways. By computationally modulating the electrostatic interactions between the chromophore phenoxy oxygen and its nearby residues, we demonstrate that we indeed can shift the emission to the blue or to the red side in a predictable manner. We rationalize the shifting effects of individual residues in the GFP based on the responses of both the adiabatic and the diabatic electronic states of the chromophore. We next exhibit that the yellow emitting variant, the Thr203Tyr mutant, generates changes in the electrostatic interactions and an additional π-stacking interaction. These combined effects indeed induce a red shift to emit the fluorescence into the yellow region. With the series of demonstrations, we suggest that our approach can provide sound rationales and useful insights in understanding different responses of various fluorescent complexes, which may be helpful in designing new light emitting proteins and other related systems in future studies.

  9. Monitoring organic loading to swimming pools by fluorescence excitation–emission matrix with parallel factor analysis (PARAFAC)

    DEFF Research Database (Denmark)

    Seredynska-Sobecka, Bozena; Stedmon, Colin; Boe-Hansen, Rasmus

    2011-01-01

    Fluorescence Excitation–Emission Matrix spectroscopy combined with parallel factor analysis was employed to monitor water quality and organic contamination in swimming pools. The fluorescence signal of the swimming pool organic matter was low but increased slightly through the day. The analysis...... revealed that the organic matter fluorescence was characterised by five different components, one of which was unique to swimming pool organic matter and one which was specific to organic contamination. The latter component had emission peaks at 420nm and was found to be a sensitive indicator of organic...... loading in swimming pool water. The fluorescence at 420nm gradually increased during opening hours and represented material accumulating through the day....

  10. ICT-Isomerization-Induced Turn-On Fluorescence Probe with a Large Emission Shift for Mercury Ion: Application in Combinational Molecular Logic.

    Science.gov (United States)

    Bhatta, Sushil Ranjan; Mondal, Bijan; Vijaykumar, Gonela; Thakur, Arunabha

    2017-10-02

    A unique turn-on fluorescent device based on a ferrocene-aminonaphtholate derivative specific for Hg 2+ cation was developed. Upon binding with Hg 2+ ion, the probe shows a dramatic fluorescence enhancement (the fluorescence quantum yield increases 58-fold) along with a large red shift of 68 nm in the emission spectrum. The fluorescence enhancement with a red shift may be ascribed to the combinational effect of C═N isomerization and an extended intramolecular charge transfer (ICT) mechanism. The response was instantaneous with a detection limit of 2.7 × 10 -9 M. Upon Hg 2+ recognition, the ferrocene/ferrocenium redox peak was anodically shifted by ΔE 1/2 = 72 mV along with a "naked eye" color change from faint yellow to pale orange for this metal cation. Further, upon protonation of the imine nitrogen, the present probe displays a high fluorescence output due to suppression of the C═N isomerization process. Upon deprotonation using strong base, the fluorescence steadily decreases, which indicates that H + and OH - can be used to regulate the off-on-off fluorescence switching of the present probe. Density functional theory studies revealed that the addition of acid leads to protonation of the imine N (according to natural bond orbital analysis), and the resulting iminium proton forms a strong H-bond (2.307 Å) with one of the triazole N atoms to form a five-membered ring, which makes the molecule rigid; hence, enhancement of the ICT process takes place, thereby leading to a fluorescence enhancement with a red shift. The unprecedented combination of H + , OH - , and Hg 2+ ions has been used to generate a molecular system exhibiting the INHIBIT-OR combinational logic operation.

  11. 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.

  12. Nitrogen-Doped Carbon Quantum Dots as Fluorescent Probes for Sensitive and Selective Detection of Nitrite

    Directory of Open Access Journals (Sweden)

    Zhibiao Feng

    2017-11-01

    Full Text Available Nitrites are the upstream precursors of the carcinogenic nitrosamines, which are widely found in the natural environment and many food products. It is important to develop a simple and sensitive sensor for detecting nitrites. In this work, a fluorescence probe based on nitrogen-doped carbon quantum dots (N-CQDs was developed for the sensitive and selective determination of nitrites. At pH 2, the fluorescence of N-CQDs can be selectively quenched by nitrite due to the fact N-nitroso compounds can be formed in the reaction of amide groups with nitrous acid, which results in fluorescence static quenching. Under optimal conditions, fluorescence intensity quenching upon addition of nitrite gives a satisfactory linear relationship covering the linear range of 0.2–20 μM, and the limit of detection (LOD is 40 nM. Moreover, this method has been successfully applied to the determination of nitrites in tap water, which indicates its great potential for monitoring of nitrites in environmental samples.

  13. Mitigation of Nitrogen Emissions from Animal Agriculture in Europe

    Science.gov (United States)

    Oenema, O.

    2011-12-01

    More than 70% of the utilized agricultural area (187 Mha) in the 27 Member States of the European Union (EU-27) is used for animal production. In addition, a considerable amount of animal feed is imported. Dairy and beef cattle, pigs, and poultry are the dominant animal species. Total livestock density is highest in the Netherlands, Belgium, Ireland, Denmark and some regions in France, Germany and Italy. The mean nitrogen (N) retention in animal products in EU-27 in 2005 was 20% for milk, 8% for beef, 25% for pork, 38% for poultry and 28% for egg production. This indicates that dairy cows excreted on average 80% of the N intake, beef cattle 92%, pigs 75%, poultry 62% and layers 72%. There was a large variation in N retention between countries. Animal manures and nitrogen (N) fertilizers are main sources of N emissions. In 2005, mean N excretion by animals ranged from less than 25 kg per ha per year in Bulgaria to nearly 250 kg per ha in The Netherlands. On average 25% of the total amount of N excreted was lost as ammonia (NH3) to the atmosphere, though with a considerable variation between countries. About 10% was lost as NH3-N from housing systems, 9% from manure application to land, 4% from manure storage and treatment facilities, and 3% from grazing. Nitrogen leaching was in the same order of magnitude. Animal production also had a considerable share in the total emissions of greenhouse gases to the atmosphere (range 5-25%). Especially dairy cattle and beef cattle contribute to the emissions of methane (CH4) and nitrous oxide (N2O) to the atmosphere. Considerable efforts are being made to decrease N emissions from agriculture in EU-27. Good agricultural practices and mandatory emission mitigation measures are enforced through EU environmental policies, including Nitrates Directive, National Emissions Ceiling Directive, and Water Framework Directive. Some countries have succeeded to decrease the NH3 emissions to air and N leaching losses to groundwater and

  14. Effects of liming and nitrogen fertilizer application on soil acidity and gaseous nitrogen oxide emissions in grassland systems

    NARCIS (Netherlands)

    Oenema, O.; Sapek, A.

    2000-01-01

    This book contains 10 articles on the EU research project COGANOG (Controlling Gaseous Nitrogen Oxide Emissions from Grassland Farming Systems in Europe). The papers present the results of studies on the effects of liming and N fertilizer application

  15. Electron spin contrast of Purcell-enhanced nitrogen-vacancy ensembles in nanodiamonds

    Science.gov (United States)

    Bogdanov, S.; Shalaginov, M. Y.; Akimov, A.; Lagutchev, A. S.; Kapitanova, P.; Liu, J.; Woods, D.; Ferrera, M.; Belov, P.; Irudayaraj, J.; Boltasseva, A.; Shalaev, V. M.

    2017-07-01

    Nitrogen-vacancy centers in diamond allow for coherent spin-state manipulation at room temperature, which could bring dramatic advances to nanoscale sensing and quantum information technology. We introduce a method for the optical measurement of the spin contrast in dense nitrogen-vacancy (NV) ensembles. This method brings insight into the interplay between the spin contrast and fluorescence lifetime. We show that for improving the spin readout sensitivity in NV ensembles, one should aim at modifying the far-field radiation pattern rather than enhancing the emission rate.

  16. Fast-freezing with liquid nitrogen preserves bulk dissolved organic matter concentrations, but not its composition

    DEFF Research Database (Denmark)

    Thieme, Lisa; Graeber, Daniel; Kaupenjohann, Martin

    2016-01-01

    -freezing with liquid nitrogen) on DOM concentrations measured as organic carbon (DOC) concentrations and on spectroscopic properties of DOM from different terrestrial ecosystems (forest and grassland). Fresh and differently frozen throughfall, stemflow, litter leachate and soil solution samples were analyzed for DOC...... concentrations, UV-vis absorption and fluorescence excitation–emission matrices combined with parallel factor analysis (PARAFAC). Fast-freezing with liquid nitrogen prevented a significant decrease of DOC concentrations observed after freezing at −18 °C. Nonetheless, the share of PARAFAC components 1 (EXmax...... component 4 (EXmax: 280 nm, EXmax: 328 nm) to total fluorescence was not affected by freezing. We recommend fast-freezing with liquid nitrogen for preservation of bulk DOC concentrations of samples from terrestrial sources, whereas immediate measuring is preferable to preserve spectroscopic properties...

  17. Nonclassical polarization effects in fluorescence emission spectra from microdroplets

    Science.gov (United States)

    Arnold, S.; Goddard, N. L.; Hill, S. C.

    1999-12-01

    We report a pronounced nonclassical polarization effect on the shape of fluorescence emission spectra from isolated microdroplets containing a dilute solution of soluble fluors or a dilute layer of surfactant fluors. We see different spectral shapes for 90° scattering when comparing between IVV, IVH, IHH, IHV. However, we measure the largest difference in spectral shape in the surfactant case, with the incident polarization directed toward the detector (IHV vs IHH). Imaging reveals that the emission in this case principally arises from two distinct regions near the surface of the droplet, which are diametrically opposed and along the axis of the incident laser beam. The effect appears to be the direct result of coupling between molecular emission moments and electromagnetic modes of the droplet. It is not the molecule which radiates but the molecule microvessel. Directional emission is sensitive to the polarization of the electromagnetic mode which is stimulated by the coupling.

  18. Does chronic nitrogen deposition during biomass growth affect atmospheric emissions from biomass burning?

    Science.gov (United States)

    Michael R Giordano; Joey Chong; David R Weise; Akua A Asa-Awuku

    2016-01-01

    Chronic nitrogen deposition has measureable impacts on soil and plant health.We investigate burning emissions from biomass grown in areas of high and low NOx deposition. Gas and aerosolphase emissions were measured as a function of photochemical aging in an environmental chamber at UC-Riverside. Though aerosol chemical speciation was not...

  19. Characterization of dissolved organic matter in fogwater by excitation-emission matrix fluorescence spectroscopy

    Science.gov (United States)

    Birdwell, J.E.; Valsaraj, K.T.

    2010-01-01

    Dissolved organic matter (DOM) present in fogwater samples collected in southeastern Louisiana and central-eastern China has been characterized using excitation-emission matrix fluorescence spectroscopy. The goal of the study was to illustrate the utility of fluorescence for obtaining information on the large fraction of organic carbon in fogwaters (typically >40% by weight) that defies characterization in terms of specific chemical compounds without the difficulty inherent in obtaining sufficient fogwater volume to isolate DOM for assessment using other spectroscopic and chemical analyses. Based on the findings of previous studies using other characterization methods, it was anticipated that the unidentified organic carbon fraction would have characteristic peaks associated with humic substances and fluorescent amino acids. Both humic- and protein-like fluorophores were observed in the fogwater spectra and fluorescence-derived indices for the fogwater had similar values to those of soil and sediment porewater. Greater biological character was observed in samples with higher organic carbon concentrations. Fogwaters are shown to contain a mixture of terrestrially- and microbially-derived fluorescent organic material, which is expected to be derived from an array of different sources, such as suspended soil and dust particles, biogenic emissions and organic substances generated by atmospheric processes. The fluorescence results indicate that much of the unidentified organic carbon present in fogwater can be represented by humic-like and biologically-derived substances similar to those present in other aquatic systems, though it should be noted that fluorescent signatures representative of DOM produced by atmospheric processing of organic aerosols may be contributing to or masked by humic-like fluorophores. ?? 2010.

  20. Differentiation of ocular fundus fluorophores by fluorescence lifetime imaging using multiple excitation and emission wavelengths

    Science.gov (United States)

    Hammer, M.; Schweitzer, D.; Schenke, S.; Becker, W.; Bergmann, A.

    2006-10-01

    Ocular fundus autofluorescence imaging has been introduced into clinical diagnostics recently. It is in use for the observation of the age pigment lipofuscin, a precursor of age - related macular degeneration (AMD). But other fluorophores may be of interest too: The redox pair FAD - FADH II provides information on the retinal energy metabolism, advanced glycation end products (AGE) indicate protein glycation associated with pathologic processes in diabetes as well as AMD, and alterations in the fluorescence of collagen and elastin in connective tissue give us the opportunity to observe fibrosis by fluorescence imaging. This, however, needs techniques able to differentiate particular fluorophores despite limited permissible ocular exposure as well as excitation wavelength (limited by the transmission of the human ocular lens to >400 nm). We present an ophthalmic laser scanning system (SLO), equipped with picosecond laser diodes (FWHM 100 ps, 446 nm or 468 nm respectively) and time correlated single photon counting (TCSPC) in two emission bands (500 - 560 nm and 560 - 700 nm). The decays were fitted by a bi-exponential model. Fluorescence spectra were measured by a fluorescence spectrometer fluorolog. Upon excitation at 446 nm, the fluorescence of AGE, FAD, and lipofuscin were found to peak at 503 nm, 525 nm, and 600 nm respectively. Accordingly, the statistical distribution of the fluorescence decay times was found to depend on the different excitation wavelengths and emission bands used. The use of multiple excitation and emission wavelengths in conjunction with fluorescence lifetime imaging allows us to discriminate between intrinsic fluorophores of the ocular fundus. Taken together with our knowledge on the anatomical structure of the fundus, these findings suggest an association of the short, middle and long fluorescence decay time to the retinal pigment epithelium, the retina, and connective tissue respectively.

  1. Spatial Variability Analysis of Within-Field Winter Wheat Nitrogen and Grain Quality Using Canopy Fluorescence Sensor Measurements

    Directory of Open Access Journals (Sweden)

    Xiaoyu Song

    2017-03-01

    Full Text Available Wheat grain protein content (GPC is a key component when evaluating wheat nutrition. It is also important to determine wheat GPC before harvest for agricultural and food process enterprises in order to optimize the wheat grading process. Wheat GPC across a field is spatially variable due to the inherent variability of soil properties and position in the landscape. The objectives of this field study were: (i to assess the spatial and temporal variability of wheat nitrogen (N attributes related to the grain quality of winter wheat production through canopy fluorescence sensor measurements; and (ii to examine the influence of spatial variability of soil N and moisture across different growth stages on the wheat grain quality. A geostatistical approach was used to analyze data collected from 110 georeferenced locations. In particular, Ordinary Kriging Analysis (OKA was used to produce maps of wheat GPC, GPC yield, and wheat canopy fluorescence parameters, including simple florescence ratio and Nitrogen Balance Indices (NBI. Soil Nitrate-Nitrogen (NO3-N content and soil Time Domain Reflectometry (TDR value in the study field were also interpolated through the OKA method. The fluorescence parameter maps, soil NO3-N and soil TDR maps obtained from the OKA output were compared with the wheat GPC and GPC yield maps in order to assess their relationships. The results of this study indicate that the NBI spatial variability map in the late stage of wheat growth can be used to distinguish areas that produce higher GPC.

  2. Visible sub-band gap photoelectron emission from nitrogen doped and undoped polycrystalline diamond films

    Energy Technology Data Exchange (ETDEWEB)

    Elfimchev, S., E-mail: sergeyel@tx.technion.ac.il; Chandran, M.; Akhvlediani, R.; Hoffman, A.

    2017-07-15

    Highlights: • Nitrogen related centers in diamond film are mainly responsible for visible sub-band-gap photoelectron emission. • The influence of film thickness and substrate on the measured photoelectron emission yields was not found. • Nanocrystalline diamonds have low electron emission yields most likely because of high amount of defects. • Visible sub-band gap photoelectron emission may increase with temperature due to electron trapping/detrapping processes. - Abstract: In this study the origin of visible sub-band gap photoelectron emission (PEE) from polycrystalline diamond films is investigated. The PEE yields as a function of temperature were studied in the wavelengths range of 360–520 nm. Based on the comparison of electron emission yields from diamond films deposited on silicon and molybdenum substrates, with different thicknesses and nitrogen doping levels, we suggested that photoelectrons are generated from nitrogen related centers in diamond. Our results show that diamond film thickness and substrate material have no significant influence on the PEE yield. We found that nanocrystalline diamond films have low electron emission yields, compared to microcrystalline diamond, due to the presence of high amount of defects in the former, which trap excited electrons before escaping into the vacuum. However, the low PEE yield of nanocrystalline diamond films was found to increase with temperature. The phenomenon was explained by the trap assisted photon enhanced thermionic emission (ta-PETE) model. According to the ta-PETE model, photoelectrons are trapped by shallow traps, followed by thermal excitation at elevated temperatures and escape into the vacuum. Activation energies of trap levels were estimated for undoped nanocrystalline, undoped microcrystalline and N-doped diamond films using the Richardson-Dushman equation, which gives 0.13, 0.39 and 0.04 eV, respectively. Such low activation energy of trap levels makes the ta-PETE process very

  3. 40 CFR 60.33b - Emission guidelines for municipal waste combustor metals, acid gases, organics, and nitrogen oxides.

    Science.gov (United States)

    2010-07-01

    ... combustor metals, acid gases, organics, and nitrogen oxides. 60.33b Section 60.33b Protection of Environment... Constructed on or Before September 20, 1994 § 60.33b Emission guidelines for municipal waste combustor metals, acid gases, organics, and nitrogen oxides. (a) The emission limits for municipal waste combustor metals...

  4. Nitrapyrin addition mitigates nitrous oxide emissions and raises nitrogen use efficiency in plastic-film-mulched drip-fertigated cotton field.

    Science.gov (United States)

    Liu, Tao; Liang, Yongchao; Chu, Guixin

    2017-01-01

    Nitrification inhibitors (NIs) have been used extensively to reduce nitrogen losses and increase crop nitrogen nutrition. However, information is still scant regarding the influence of NIs on nitrogen transformation, nitrous oxide (N2O) emission and nitrogen utilization in plastic-film-mulched calcareous soil under high frequency drip-fertigated condition. Therefore, a field trial was conducted to evaluate the effect of nitrapyrin (2-chloro-6-(trichloromethyl)-pyridine) on soil mineral nitrogen (N) transformation, N2O emission and nitrogen use efficiency (NUE) in a drip-fertigated cotton-growing calcareous field. Three treatments were established: control (no N fertilizer), urea (225 kg N ha-1) and urea+nitrapyrin (225 kg N ha-1+2.25 kg nitrapyrin ha-1). Compared with urea alone, urea plus nitrapyrin decreased the average N2O emission fluxes by 6.6-21.8% in June, July and August significantly in a drip-fertigation cycle. Urea application increased the seasonal cumulative N2O emission by 2.4 kg N ha-1 compared with control, and nitrapyrin addition significantly mitigated the seasonal N2O emission by 14.3% compared with urea only. During the main growing season, the average soil ammonium nitrogen (NH4+-N) concentration was 28.0% greater and soil nitrate nitrogen (NO3--N) concentration was 13.8% less in the urea+nitrapyrin treatment than in the urea treatment. Soil NO3--N and water-filled pore space (WFPS) were more closely correlated than soil NH4+-N with soil N2O fluxes under drip-fertigated condition (Puse efficiency by 10.7%. The results demonstrated that nitrapyrin addition significantly inhibited soil nitrification and maintained more NH4+-N in soil, mitigated N2O losses and improved nitrogen use efficiency in plastic-film-mulched calcareous soil under high frequency drip-fertigated condition.

  5. Photoinduced intramolecular charge transfer (ICT) reaction in trans-methyl p-(dimethylamino) cinnamate: A combined fluorescence measurement and quantum chemical calculations

    Energy Technology Data Exchange (ETDEWEB)

    Chakraborty, Amrita [Department of Chemistry, University of Calcutta, 92, A. P. C. Road, Kolkata 700009 (India); Kar, Samiran [Department of Organic Chemistry, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032 (India); Guchhait, Nikhil [Department of Chemistry, University of Calcutta, 92, A. P. C. Road, Kolkata 700009 (India)], E-mail: nikhilg@postmark.net

    2006-01-05

    The photophysical behaviour of trans-methyl p-(dimethylamino) cinnamate (t-MDMAC) donor-acceptor system has been investigated by steady-state absorption and emission spectroscopy and quantum chemical calculations. The molecule t-MDMAC shows an emission from the locally excited state in non-polar solvents. In addition to weak local emission, a strong solvent dependent red shifted fluorescence in polar aprotic solvents is attributed to highly polar intramolecular charge transfer state. However, the formation of hydrogen-bonded clusters with polar protic solvents has been suggested from a linear correlation between the observed red shifted fluorescence band maxima with hydrogen bonding parameters ({alpha}). Calculations by ab initio and density functional theory show that the lone pair electron at nitrogen center is out of plane of the benzene ring in the global minimum ground state structure. In the gas phase, a potential energy surface along the twist coordinate at the donor (-NMe{sub 2}) and acceptor (-CH = CHCOOMe) sites shows stabilization of S{sub 1} state and destabilization S{sub 2} and S{sub 0} states. A similar potential energy calculation along the twist coordinate in acetonitrile solvent using non-equilibrium polarized continuum model also shows more stabilization of S{sub 1} state relative to other states and supports solvent dependent red shifted emission properties. In all types of calculations it is found that the nitrogen lone pair is delocalized over the benzene ring in the global minimum ground state and is localized on the nitrogen centre at the 90 deg. twisted configuration. The S{sub 1} energy state stabilization along the twist coordinate at the donor site and localized nitrogen lone pair at the perpendicular configuration support well the observed dual fluorescence in terms of proposed twisted intramolecular charge transfer (TICT) model.

  6. Silver-graphene oxide based plasmonic spacer for surface plasmon-coupled fluorescence emission enhancements

    Science.gov (United States)

    Badiya, Pradeep Kumar; Srinivasan, Venkatesh; Sathish Ramamurthy, Sai

    2017-06-01

    We report the application of single layered graphene oxide (SLGO) and silver decorated SLGO (Ag-SLGO) as plasmonic spacer material for obtaining enhanced fluorescence from a Rhodamine 6G (Rh6G) radiating dipole in a surface plasmon-coupled emission platform. To this end, we have decorated SLGO with biphasic silver nanoparticles using an in situ deposition technique to achieve 112-fold fluorescence enhancements.

  7. Direct and Indirect Electron Emission from the Green Fluorescent Protein Chromophore

    Science.gov (United States)

    Toker, Y.; Rahbek, D. B.; Klærke, B.; Bochenkova, A. V.; Andersen, L. H.

    2012-09-01

    Photoelectron spectra of the deprotonated green fluorescent protein chromophore have been measured in the gas phase at several wavelengths within and beyond the S0-S1 photoabsorption band of the molecule. The vertical detachment energy (VDE) was determined to be 2.68±0.1eV. The data show that the first electronically excited state is bound in the Franck-Condon region, and that electron emission proceeds through an indirect (resonant) electron-emission channel within the corresponding absorption band.

  8. Methane emissions from a freshwater marsh in response to experimentally simulated global warming and nitrogen enrichment

    DEFF Research Database (Denmark)

    Flury, Sabine; McGinnis, Daniel Frank; Gessner, Mark O.

    2010-01-01

    We determined methane (CH4) emissions in a field enclosure experiment in a littoral freshwater marsh under the influence of experimentally simulated warming and enhanced nitrogen deposition. Methane emissions by ebullition from the marsh composed of Phragmites australis were measured with funnel ...... to the atmosphere, even when they occupy only relatively small littoral areas. More detailed investigations are clearly needed to assess whether global warming and nitrogen deposition can have climate feedbacks by altering methane fluxes from these wetlands.  ......We determined methane (CH4) emissions in a field enclosure experiment in a littoral freshwater marsh under the influence of experimentally simulated warming and enhanced nitrogen deposition. Methane emissions by ebullition from the marsh composed of Phragmites australis were measured with funnel...... traps deployed in a series of enclosures for two 3 week periods. Diffusive fluxes were estimated on the basis of measured CH4 concentrations and application of Fick's law. Neither diffusive nor ebullitive fluxes of methane were significantly affected by warming or nitrate enrichment, possibly because...

  9. One-pot synthesis of fluorescent nitrogen-doped carbon dots with good biocompatibility for cell labeling.

    Science.gov (United States)

    Zhang, Zhengwei; Yan, Kun; Yang, Qiulian; Liu, Yanhua; Yan, Zhengyu; Chen, Jianqiu

    2017-12-01

    Here we report an easy and economical hydrothermal carbonization approach to synthesize the fluorescent nitrogen-doped carbon dots (N-CDs) that was developed using citric acid and triethanolamine as the precursors. The synthesis conditions were optimized to obtain the N-CDs with superior fluorescence performances. The as-prepared N-CDs are monodispersed sphere nanoparticles with good water solubility, and exhibited strong fluorescence, favourable photostability and excitation wavelength-dependent behavior. Furthermore, the in vitro cytotoxicity and cellular labeling of N-CDs were investigated using the rat glomerular mesangial cells. The results showed the N-CDs have more inconspicuous cytotoxicity and better biosafety in comparison with ZnSe quantum dots, although both targeted the cells successfully. Considering their admirable photostability, low toxicity and good compatibility, the as-obtained N-CDs could have potential applications in biosensors, cellular imaging, and other fields. Copyright © 2017 John Wiley & Sons, Ltd.

  10. Carbon dots based dual-emission silica nanoparticles as ratiometric fluorescent probe for nitrite determination in food samples.

    Science.gov (United States)

    Xiang, Guoqiang; Wang, Yule; Zhang, Heng; Fan, Huanhuan; Fan, Lu; He, Lijun; Jiang, Xiuming; Zhao, Wenjie

    2018-09-15

    In this work, a simple and effective strategy for designing a ratiometric fluorescent nanosensor was described. A carbon dots (CDs) based dual-emission nanosensor for nitrite was prepared by coating the CDs on to dye-doped silica nanoparticles. Dual-emission silica nanoparticles fluorescence was quenched in sulfuric acid using potassium bromate (KBrO 3 ). The nitrite present catalyzed the KBrO 3 oxidation, resulting in ratiometric fluorescence response of the dual-emission silica nanoparticles. Several important parameters affecting the performance of the nanosensor were investigated. Under optimized conditions, the limit of detection was 1.0 ng mL -1 and the linear range 10-160 ng mL -1 . Furthermore, the sensor was suitable for nitrite determination in different food samples. Copyright © 2018 Elsevier Ltd. All rights reserved.

  11. Production mechanism of atomic nitrogen in atmospheric pressure pulsed corona discharge measured using two-photon absorption laser-induced fluorescence

    International Nuclear Information System (INIS)

    Teramoto, Yoshiyuki; Ono, Ryo; Oda, Tetsuji

    2012-01-01

    To study the production mechanism of atomic nitrogen, the temporal profile and spatial distribution of atomic nitrogen are measured in atmospheric pressure pulsed positive corona discharge using two-photon absorption laser-induced fluorescence. The absolute atomic nitrogen density in the streamer filaments is estimated from decay rate of atomic nitrogen in N 2 discharge. The results indicate that the absolute atomic nitrogen density is approximately constant against discharge energy. When the discharge voltage is 21.5 kV, production yield of atomic nitrogen produced by an N 2 discharge pulse is estimated to be 2.9 - 9.8 × 10 13 atoms and the energy efficiency of atomic nitrogen production is estimated to be about 1.8 - 6.1 × 10 16 atoms/J. The energy efficiency of atomic nitrogen production in N 2 discharge is constant against the discharge energy, while that in N 2 /O 2 discharge increases with discharge energy. In the N 2 /O 2 discharge, two-step process of N 2 dissociation plays significant role for atomic nitrogen production.

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

    Science.gov (United States)

    Anderson, Natalie; Strader, Ross; Davidson, Cliff

    2003-06-01

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

  13. Suppression of Kasha's rule as a mechanism for fluorescent molecular rotors and aggregation-induced emission

    Science.gov (United States)

    Qian, Hai; Cousins, Morgan E.; Horak, Erik H.; Wakefield, Audrey; Liptak, Matthew D.; Aprahamian, Ivan

    2017-01-01

    Although there are some proposed explanations for aggregation-induced emission, a phenomenon with applications that range from biosensors to organic light-emitting diodes, current understanding of the quantum-mechanical origin of this photophysical behaviour is limited. To address this issue, we assessed the emission properties of a series of BF2-hydrazone-based dyes as a function of solvent viscosity. These molecules turned out to be highly efficient fluorescent molecular rotors. This property, in addition to them being aggregation-induced emission luminogens, enabled us to probe deeper into their emission mechanism. Time-dependent density functional theory calculations and experimental results showed that the emission is not from the S1 state, as predicted from Kasha's rule, but from a higher energy (>S1) state. Furthermore, we found that suppression of internal conversion to the dark S1 state by restricting the rotor rotation enhances fluorescence, which leads to the proposal that suppression of Kasha's rule is the photophysical mechanism responsible for emission in both viscous solution and the solid state.

  14. Nitrogen gas emissions and nitrate leaching dynamics under different tillage practices based on data synthesis and process-based modeling

    Science.gov (United States)

    Huang, Y.; Ren, W.; Tao, B.; Zhu, X.

    2017-12-01

    Nitrogen losses from the agroecosystems have been of great concern to global changes due to the effects on global warming and water pollution in the form of nitrogen gas emissions (e.g., N2O) and mineral nitrogen leaching (e.g., NO3-), respectively. Conservation tillage, particularly no-tillage (NT), may enhance soil carbon sequestration, soil aggregation and moisture; therefore it has the potential of promoting N2O emissions and reducing NO3- leaching, comparing with conventional tillage (CT). However, associated processes are significantly affected by various factors, such as soil properties, climate, and crop types. How tillage management practices affect nitrogen transformations and fluxes is still far from clear, with inconsistent even opposite results from previous studies. To fill this knowledge gap, we quantitatively investigated gaseous and leaching nitrogen losses from NT and CT agroecosystems based on data synthesis and an improved process-based agroecosystem model. Our preliminary results suggest that NT management is more efficient in reducing NO3- leaching, and meanwhile it simultaneously increases N2O emissions by approximately 10% compared with CT. The effects of NT on N2O emissions and NO3- leaching are highly influenced by the placement of nitrogen fertilizer and are more pronounced in humid climate conditions. The effect of crop types is a less dominant factor in determining N2O and NO3- losses. Both our data synthesis and process-based modeling suggest that the enhanced carbon sequestration capacity from NT could be largely compromised by relevant NT-induced increases in N2O emissions. This study provides the comprehensive quantitative assessment of NT on the nitrogen emissions and leaching in agroecosystems. It provides scientific information for identifying proper management practices for ensuring food security and minimizing the adverse environmental impacts. The results also underscore the importance of suitable nitrogen management in the NT

  15. Combined effect of nitrogen doping and nanosteps on microcrystalline diamond films for improvement of field emission

    International Nuclear Information System (INIS)

    Mengui, U.A.; Campos, R.A.; Alves, K.A.; Antunes, E.F.; Hamanaka, M.H.M.O.; Corat, E.J.; Baldan, M.R.

    2015-01-01

    Highlights: • Hot filament chemical vapor deposition using methane, hydrogen and a solution of urea in methanol produced nitrogen-doped diamond films. • Diamonds had the grain morphology changed for long growth time (28 h), and the nitrogen doping were evaluated by Raman spectroscopy. • Field emission characterization shows a decrease up to 70% in threshold field, related to reference diamond layer. - Abstract: Nitrogen-doped microcrystalline diamond (N-MCD) films were grown on Si substrates using a hot filament reactor with methanol solution of urea as N source. Electrostatic self-assembly seeding of nanocrystalline diamond were used to obtain continuous and uniform films. Simultaneous changes in grains morphology and work function of diamond by nitrogen doping decreased the threshold field and the angular coefficient of Fowler–Nordhein plots. The field emission properties of our N-MCD films are comparable to carbon nanotube films

  16. Combined effect of nitrogen doping and nanosteps on microcrystalline diamond films for improvement of field emission

    Energy Technology Data Exchange (ETDEWEB)

    Mengui, U.A., E-mail: ursulamengui@gmail.com [INPE – Instituto Nacional de Pesquisas Espaciais Laboratório Associado de Sensores e Materiais – LAS, Av. dos Astronautas 1758, CP 515, CEP 12.245-970, São José dos Campos, SP (Brazil); Campos, R.A.; Alves, K.A.; Antunes, E.F. [INPE – Instituto Nacional de Pesquisas Espaciais Laboratório Associado de Sensores e Materiais – LAS, Av. dos Astronautas 1758, CP 515, CEP 12.245-970, São José dos Campos, SP (Brazil); Hamanaka, M.H.M.O. [Centro de Tecnologia da Informação Renato Archer, Divisão de Superfícies de Interação e Displays, Rodovia D. Pedro I (SP 65) km 143.6, CP 6162, CEP 13089-500, Campinas, SP (Brazil); Corat, E.J.; Baldan, M.R. [INPE – Instituto Nacional de Pesquisas Espaciais Laboratório Associado de Sensores e Materiais – LAS, Av. dos Astronautas 1758, CP 515, CEP 12.245-970, São José dos Campos, SP (Brazil)

    2015-04-15

    Highlights: • Hot filament chemical vapor deposition using methane, hydrogen and a solution of urea in methanol produced nitrogen-doped diamond films. • Diamonds had the grain morphology changed for long growth time (28 h), and the nitrogen doping were evaluated by Raman spectroscopy. • Field emission characterization shows a decrease up to 70% in threshold field, related to reference diamond layer. - Abstract: Nitrogen-doped microcrystalline diamond (N-MCD) films were grown on Si substrates using a hot filament reactor with methanol solution of urea as N source. Electrostatic self-assembly seeding of nanocrystalline diamond were used to obtain continuous and uniform films. Simultaneous changes in grains morphology and work function of diamond by nitrogen doping decreased the threshold field and the angular coefficient of Fowler–Nordhein plots. The field emission properties of our N-MCD films are comparable to carbon nanotube films.

  17. Enhanced EGFP Fluorescence Emission in Presence of PEG Aqueous Solutions and PIB1000-PEG6000-PIB1000 Copolymer Vesicles

    Directory of Open Access Journals (Sweden)

    Noor Muhammad

    2013-01-01

    Full Text Available An EGFP construct interacting with the PIB1000-PEG6000-PIB1000 vesicles surface reported a ~2-fold fluorescence emission enhancement. Because of the constructs nature with the amphiphilic peptide inserted into the PIB core, EGFP is expected to experience a “pure” PEG environment. To unravel this phenomenon PEG/water solutions at different molecular weights and concentrations were used. Already at ~1 : 10 protein/PEG molar ratio the increase in fluorescence emission is observed reaching a plateau correlating with the PEG molecular weight. Parallel experiments in presence of glycerol aqueous solutions did show a slight fluorescence enhancement however starting at much higher concentrations. Molecular dynamics simulations of EGFP in neat water, glycerol, and PEG aqueous solutions were performed showing that PEG molecules tend to “wrap” the protein creating a microenvironment where the local PEG concentration is higher compared to its bulk concentration. Because the fluorescent emission can be perturbed by the refractive index surrounding the protein, the clustering of PEG molecules induces an enhanced fluorescence emission already at extremely low concentrations. These findings can be important when related to the use of EGFP as reported in molecular biology experiments.

  18. Temperature and humidity dependence of air fluorescence yield measured by AIRFLY

    International Nuclear Information System (INIS)

    Ave, M.; Bohacova, M.; Buonomo, B.; Busca, N.; Cazon, L.; Chemerisov, S.D.; Conde, M.E.; Crowell, R.A.; Di Carlo, P.; Di Giulio, C.; Doubrava, M.; Esposito, A.; Facal, P.; Franchini, F.J.; Hoerandel, J.; Hrabovsky, M.; Iarlori, M.; Kasprzyk, T.E.; Keilhauer, B.

    2008-01-01

    The fluorescence detection of ultra high energy cosmic rays requires a detailed knowledge of the fluorescence light emission from nitrogen molecules over a wide range of atmospheric parameters, corresponding to altitudes typical of the cosmic ray shower development in the atmosphere. We have studied the temperature and humidity dependence of the fluorescence light spectrum excited by MeV electrons in air. Results for the 313.6, 337.1, 353.7 and 391.4 nm bands are reported in this paper. We found that the temperature and humidity dependence of the quenching process changes the fluorescence yield by a sizeable amount (up to 20% for the temperature dependence in the 391.4 nm band) and its effect must be included for a precise estimation of the energy of ultra high energy cosmic rays.

  19. Numerical modelling of emissions of nitrogen oxides in solid fuel combustion.

    Science.gov (United States)

    Bešenić, Tibor; Mikulčić, Hrvoje; Vujanović, Milan; Duić, Neven

    2018-06-01

    Among the combustion products, nitrogen oxides are one of the main contributors to a negative impact on the environment, participating in harmful processes such as tropospheric ozone and acid rains production. The main source of emissions of nitrogen oxides is the human combustion of fossil fuels. Their formation models are investigated and implemented with the goal of obtaining a tool for studying the nitrogen-containing pollutant production. In this work, numerical simulation of solid fuel combustion was carried out on a three-dimensional model of a drop tube furnace by using the commercial software FIRE. It was used for simulating turbulent fluid flow and temperature field, concentrations of the reactants and products, as well as the fluid-particles interaction by numerically solving the integro-differential equations describing these processes. Chemical reactions mechanisms for the formation of nitrogen oxides were implemented by the user functions. To achieve reasonable calculation times for running the simulations, as well as efficient coupling with the turbulent mixing process, the nitrogen scheme is limited to sufficiently few homogeneous reactions and species. Turbulent fluctuations that affect the reaction rates of nitrogen oxides' concentration are modelled by probability density function approach. Results of the implemented model for nitrogen oxides' formation from coal and biomass are compared to the experimental data. Temperature, burnout and nitrogen oxides' concentration profiles are compared, showing satisfactory agreement. The new model allows the simulation of pollutant formation in the real-world applications. Copyright © 2018 Elsevier Ltd. All rights reserved.

  20. Sensitivity of modeled atmospheric nitrogen species and nitrogen deposition to variations in sea salt emissions in the North Sea and Baltic Sea regions

    Directory of Open Access Journals (Sweden)

    D. Neumann

    2016-03-01

    Full Text Available Coarse sea salt particles are emitted ubiquitously from the ocean surface by wave-breaking and bubble-bursting processes. These particles impact the atmospheric chemistry by affecting the condensation of gas-phase species and, thus, indirectly the nucleation of new fine particles, particularly in regions with significant air pollution. In this study, atmospheric particle concentrations are modeled for the North Sea and Baltic Sea regions in northwestern Europe using the Community Multiscale Air Quality (CMAQ modeling system and are compared to European Monitoring and Evaluation Programme (EMEP measurement data. The sea salt emission module is extended by a salinity-dependent scaling of the sea salt emissions because the salinity in large parts of the Baltic Sea is very low, which leads to considerably lower sea salt mass emissions compared to other oceanic regions. The resulting improvement in predicted sea salt concentrations is assessed. The contribution of surf zone emissions is considered separately. Additionally, the impacts of sea salt particles on atmospheric nitrate and ammonium concentrations and on nitrogen deposition are evaluated. The comparisons with observational data show that sea salt concentrations are commonly overestimated at coastal stations and partly underestimated farther inland. The introduced salinity scaling improves the predicted Baltic Sea sea salt concentrations considerably. The dates of measured peak concentrations are appropriately reproduced by the model. The impact of surf zone emissions is negligible in both seas. Nevertheless, they might be relevant because surf zone emissions were cut at an upper threshold in this study. Deactivating sea salt leads to minor increases in NH3 +  NH4+ and HNO3 +  NO3− and a decrease in NO3− concentrations. However, the overall effect on NH3 +  NH4+ and HNO3 +  NO3− concentrations is smaller than the deviation from the measurements. Nitrogen wet deposition is

  1. Measurement of fluorescence emission spectrum of few strongly driven atoms using an optical nanofiber.

    Science.gov (United States)

    Das, Manoj; Shirasaki, A; Nayak, K P; Morinaga, M; Le Kien, Fam; Hakuta, K

    2010-08-02

    We show that the fluorescence emission spectrum of few atoms can be measured by using an optical nanofiber combined with the optical heterodyne and photon correlation spectroscopy. The observed fluorescence spectrum of the atoms near the nanofiber shows negligible effects of the atom-surface interaction and agrees well with the Mollow triplet spectrum of free-space atoms at high excitation intensity.

  2. Nitrogen plasma formation through terahertz-induced ultrafast electron field emission

    DEFF Research Database (Denmark)

    Iwaszczuk, Krzysztof; Zalkovskij, Maksim; Strikwerda, Andrew

    2015-01-01

    Electron microscopy and electron diffraction techniques rely on electron sources. Those sources require strong electric fields to extract electrons from metals, either by the photoelectric effect, driven by multiphoton absorption of strong laser fields, or in the static field emission regime....... Terahertz (THz) radiation, commonly understood to be nonionizing due to its low photon energy, is here shown to produce electron field emission. We demonstrate that a carrier-envelope phase-stable single-cycle optical field at THz frequencies interacting with a metallic microantenna can generate...... and accelerate ultrashort and ultrabright electron bunches into free space, and we use these electrons to excite and ionize ambient nitrogen molecules near the antenna. The associated UV emission from the gas forms a novel THz wave detector, which, in contrast with conventional photon-counting or heat...

  3. New dual emission fluorescent sensor for pH and Pb(II) based on bis(napfthalimide) derivative

    International Nuclear Information System (INIS)

    Pina-Luis, Georgina; Martínez-Quiroz, Marisela; Ochoa-Terán, Adrián; Santacruz-Ortega, Hisila; Mendez-Valenzuela, Eduardo

    2013-01-01

    This paper describes a novel dual emission bis-1,8-naphthalimide sensor for selective determination of pH and Pb 2+ ions. The influence of the variability in the backbone that links the two fluorophores (naphthalimides) as a function of pH and metal ions was studied by UV–visible and fluorescence spectroscopy. Compounds 1(a–d) with different length alkyl linkers (CH 2 ) n (n=1, 2, 4 and 6) showed no excimer formation in aqueous solution. Fluorescence emission of these derivatives varied in a narrow range of pH (5–8) and was only slightly influenced by the addition of metal ions in CH 3 CN solutions. However, derivative 1e with amino-containing spacer (CH 2 –NH–CH 2 ) showed excimer emission in aqueous solution, a wide response to pH (2.5–9.5) and fluorescence enhancement with selective behavior towards metal ions. The pH sensor based in derivative 1e has a sufficient selectivity for practical pH monitoring in the presence of Li + , Na + , K + , Cs + , Ca 2+ , Mg 2+ , Ba 2+ , Cu 2+ , Pb 2+ , Ni 2+ , Zn 2+ and Cd 2+ . The coordination chemistry of these complexes was studied by UV–Vis, fluorescence and 1 H NMR. This chemosensor displayed high selectivity fluorescence enhancement toward Pb 2+ ions in the presence of the metals ions mentioned in CH 3 CN solutions. Competitive assays show that a 1-fold of metal cations in each case, compared with Pb 2+ ions, results in less than ±5% fluorescence intensity changes. Linear calibration up to 1×10 −5 M for Pb(II) ions (R=0.9968) was obtained and detection limit resulted of 5.0×10 −8 M. - Highlights: ► A novel dual emission bis-1,8-naphthalimide sensor for pH and Pb 2+ ions is synthetized. ► The excimer formation depends on the spacer that links the two naphthalimide groups. ► Bis(naphthalimide) with amino-containing spacer showed a wide selective response to pH. ► This chemosensor displayed a selective fluorescence enhancement effect towards Pb 2+ ions. ► Mechanism for the fluorescence OFF

  4. The HST-pNFL program: Mapping the Fluorescent Emission of Galactic Outflows

    Science.gov (United States)

    Heckman, Timothy

    2017-08-01

    Galactic outflows associated with star formation are believed to play a crucial role in the evolution of galaxies and the IGM. Most of our knowledge about outflows has come from down-the-barrel UV absorption spectroscopy of star-forming galaxies. However, absorption-line data alone provide only indirect information about the radial structure of the gas flows, which introduces large systematic uncertainties in some of the most important quantities, such as the outflow rate, the mass loading factor, and the momentum, metal, and energy fluxes. Recent spectroscopic observations of star-forming galaxies with large (projected physical) apertures have revealed non-resonant (fluorescent) emission in the UV, e.g., FeII* and SiII*, that can be naturally produced by spatially extended emission from the same outflowing material traced in absorption. Encouraged by the most recent observations of FeII* emission by the SDSS-IV/eBOSS survey (Zhu et al. 2015), we propose a pilot program to use narrow-band filter UVIS F280N images to map the extended FeII* 2626 and 2613 fluorescent emission in a carefully-chosen sample of 4 starburst galaxies at z=0.065, and COS G130M to obtain down-the- barrel spectra for SiII absorption and SiII* emission. This HST pilot program can provide unique information about the spatial structure of galactic outflows and can potentially lead to a revolution in our understanding of outflow physics and its impact on galaxies and the IGM.

  5. Comparison of Measurements and FluorMOD Simulations for Solar Induced Chlorophyll Fluorescence and Reflectance of a Corn Crop under Nitrogen Treatments [SIF and Reflectance for Corn

    Science.gov (United States)

    Middleton, Elizabeth M.; Corp, Lawrence A.; Campbell, Petya K. E.

    2007-01-01

    The FLuorescence Explorer (FLEX) satellite concept is one of six semifinalist mission proposals selected in 2006 for pre-Phase studies by the European Space Agency (ESA). The FLEX concept proposes to measure passive solar induced chlorophyll fluorescence (SIF) of terrestrial ecosystems. A new spectral vegetation Fluorescence Model (FluorMOD) was developed to include the effects of steady state SIF on canopy reflectance. We used our laboratory and field measurements previously acquired from foliage and canopies of corn (Zea mays L.) under controlled nitrogen (N) fertilization to parameterize and evaluate FluorMOD. Our data included biophysical properties, fluorescence (F) and reflectance spectra for leaves; reflectance spectra of canopies and soil; solar irradiance; plot-level leaf area index; and canopy SIF emissions determined using the Fraunhofer Line Depth principal for the atmospheric telluric oxygen absorption features at 688 nm (O2-beta) and 760 nm (O2-alpha). FluorMOD simulations implemented in the default "look-up-table" mode did not reproduce the observed magnitudes of leaf F, canopy SIF, or canopy reflectance. However, simulations for all of these parameters agreed with observations when the default FluorMOD information was replaced with measurements, although N treatment responses were underestimated. Recommendations were provided to enhance FluorMOD's potential utility in support of SIF field experiments and studies of agriculture and ecosystems.

  6. Nitrogen enriched combustion of a natural gas internal combustion engine to reduce NO.sub.x emissions

    Science.gov (United States)

    Biruduganti, Munidhar S.; Gupta, Sreenath Borra; Sekar, R. Raj; McConnell, Steven S.

    2008-11-25

    A method and system for reducing nitrous oxide emissions from an internal combustion engine. An input gas stream of natural gas includes a nitrogen gas enrichment which reduces nitrous oxide emissions. In addition ignition timing for gas combustion is advanced to improve FCE while maintaining lower nitrous oxide emissions.

  7. A dual-emission and large Stokes shift fluorescence probe for real-time discrimination of ROS/RNS and imaging in live cells.

    Science.gov (United States)

    Guo, Ting; Cui, Lei; Shen, Jiaoning; Wang, Rui; Zhu, Weiping; Xu, Yufang; Qian, Xuhong

    2013-03-04

    A novel dual-emission fluorescence probe has been developed for specific and sensitive detection of hypochlorite (ClO(-)). Upon addition of ClO(-), significant changes in fluorescence emission intensity at two discrete wavelengths were observed. Meanwhile OONO(-) led to only a single-channel fluorescence enhancement. This feature makes it a clear advantage in distinguishing ClO(-), RNS from other ROS.

  8. Composite model describing the excitation and de-excitation of nitrogen by an electron beam

    International Nuclear Information System (INIS)

    Kassem, A.E.; Hickman, R.S.

    1975-01-01

    Based on recent studies, the effect of re-excited ions in the emission of electron beam induced fluorescence in nitrogen has been estimated. These effects are included in the formulation of a composite model describing the excitation and de-excitation of nitrogen by an electron beam. The shortcomings of previous models, namely the dependence of the measured temperature on true gas temperature as well as the gas density, are almost completely eliminated in the range of temperatures and densities covered by the available data. (auth)

  9. Ratiometric fluorescent detection of chromium(VI) in real samples based on dual emissive carbon dots.

    Science.gov (United States)

    Ma, Yunxia; Chen, Yonglei; Liu, Juanjuan; Han, Yangxia; Ma, Sudai; Chen, Xingguo

    2018-08-01

    As we know, hexavalent chromium (Cr(VI)) was usually used as an additive to improve the color fastness during the printing and dyeing process, and thus posing tremendous threat to our health and living quality. In this work, the dual emissive carbon dots (DECDs) were synthesized through hydrothermal treatment of m-aminophenol and oxalic acid. The obtained DECDs not only exhibited dual emission fluorescence peaks (430 nm, 510 nm) under the single excitation wavelength of 380 nm, but also possessed good water solubility and excellent fluorescence stability. A ratiometric fluorescent method for the determination of Cr(VI) was developed using the DECDs as a probe. Under the optimal conditions, a linear range was obtained from 2 to 300 μM with a limit of detection of 0.4 μM. Furthermore, the proposed ratiometric fluorescent method was applied to the analysis of Cr(VI) in textile, steel, industrial wastewater and chromium residue samples with satisfactory recoveries (88.4-106.8%). Copyright © 2018 Elsevier B.V. All rights reserved.

  10. Photobleaching kinetics and time-integrated emission of fluorescent probes in cellular membranes

    DEFF Research Database (Denmark)

    Wüstner, Daniel; Christensen, Tanja; Solanko, Lukasz Michal

    2014-01-01

    Since the pioneering work of Hirschfeld, it is known that time-integrated emission (TiEm) of a fluorophore is independent of fluorescence quantum yield and illumination intensity. Practical implementation of this important result for determining exact probe distribution in living cells is often h...

  11. BVOCs emission in a semi-arid grassland under climate warming and nitrogen deposition

    Directory of Open Access Journals (Sweden)

    H. J. Wang

    2012-04-01

    Full Text Available Biogenic volatile organic compounds (BVOCs profoundly affect atmospheric chemistry and ecosystem functioning. BVOCs emission and their responses to global change are still unclear in grasslands, which cover one quarter of the Earth's land surface and are currently undergoing the largest changes. Over two growing seasons, we conducted a field experiment in a semi-arid grassland (Inner Mongolia, China to examine the emission and the responses of BVOCs emissions to warming and nitrogen deposition. The natural emission rate (NER of monoterpene (dominant BVOCs here is 107 ± 16 μg m−2 h−1 in drought 2007, and 266 ± 53 μg m−2 h−1 in wet 2008, respectively. Warming decreased the standard emission factor (SEF by 24% in 2007, while it increased by 43% in 2008. The exacerbated soil moisture loss caused by warming in dry season might be responsible for the decrease of SEF in 2007. A possible threshold of soil moisture (8.2% (v/v, which controls the direction of warming effects on monoterpene emission, existed in the semiarid grassland. Nitrogen deposition decreased the coverage of Artemisia frigida and hence reduced the NER by 24% across the two growing seasons. These results suggest that the grasslands dominated by the extended Artemisia frigida are an important source for BVOCs, while the responses of their emissions to global changes are more uncertain since they depend on multifactorial in-situ conditions.

  12. 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.

  13. Real-time measurements of nitrogen oxide emissions from in-use New York City transit buses using a chase vehicle.

    Science.gov (United States)

    Shorter, Joanne H; Herndon, Scott; Zahniser, Mark S; Nelson, David D; Wormhoudt, Joda; Demerjian, Kenneth L; Kolb, Charles E

    2005-10-15

    New diesel engine technologies and alternative fuel engines are being introduced into fleets of mass transit buses to try to meet stricter emission regulations of nitrogen oxides and particulates: Real-time instruments including an Aerodyne Research tunable infrared laser differential absorption spectrometer (TILDAS) were deployed in a mobile laboratory to assess the impact of the implementation of the new technologies on nitrogen oxide emissions in real world driving conditions. Using a "chase" vehicle sampling strategy, the mobile laboratory followed target vehicles, repeatedly sampling their exhaust. Nitrogen oxides from approximately 170 in-use New York City mass transit buses were sampled during the field campaigns. Emissions from conventional diesel buses, diesel buses with continuously regenerating technology (CRT), diesel hybrid electric buses, and compressed natural gas (CNG) buses were compared. The chase vehicle sampling method yields real world emissions that can be included in more realistic emission inventories. The NO, emissions from the diesel and CNG buses were comparable. The hybrid electric buses had approximately one-half the NOx emissions. In CRT diesels, NO2 accounts for about one-third of the NOx emitted in the exhaust, while for non-CRT buses the NO2 fraction is less than 10%.

  14. Stacking the Cosmic Web in fluorescent Ly α emission with MUSE

    Science.gov (United States)

    Gallego, Sofia G.; Cantalupo, Sebastiano; Lilly, Simon; Marino, Raffaella Anna; Pezzulli, Gabriele; Schaye, Joop; Wisotzki, Lutz; Bacon, Roland; Inami, Hanae; Akhlaghi, Mohammad; Tacchella, Sandro; Richard, Johan; Bouche, Nicolas F.; Steinmetz, Matthias; Carollo, Marcella

    2018-04-01

    Cosmological simulations suggest that most of the matter in the Universe is distributed along filaments connecting galaxies. Illuminated by the cosmic UV background (UVB), these structures are expected to glow in fluorescent Ly α emission with a surface brightness (SB) that is well below current limits for individual detections. Here, we perform a stacking analysis of the deepest MUSE/VLT data using three-dimensional regions (subcubes) with orientations determined by the position of neighbouring Ly α galaxies at 3 < z < 4. Our method increase the probability of detecting filamentary Ly α emission, provided that these structures are Lyman-limit systems (LLSs). By stacking 390 oriented subcubes we reach a 2σ sensitivity level of SB ≈ 0.44 × 10-20 erg s-1 cm-2 arcsec-2 in an aperture of 1 arcsec2 × 6.25 Å, three times below the expected fluorescent Ly α signal from the Haardt & Madau UVB at z ˜ 3.5. No detectable emission is found on intergalactic scales, implying that at least two thirds of our subcubes do not contain oriented LLSs. On the other hand, significant emission is detected in the circumgalactic medium (CGM) in the direction of the neighbours. The signal is stronger for galaxies with a larger number of neighbours and appears to be independent of any other galaxy properties. We estimate that preferentially oriented satellite galaxies cannot contribute significantly to this signal, suggesting instead that gas densities in the CGM are typically larger in the direction of neighbouring galaxies on cosmological scales.

  15. Nitrogen loading and nitrous oxide emissions from a river with multiple hydroelectric reservoirs.

    Science.gov (United States)

    Chen, Jinsong; Cao, Wenzhi; Cao, Di; Huang, Zheng; Liang, Ying

    2015-05-01

    River networks receive a large fraction of the anthropogenic nitrogen applied to river catchments. The different impacts of the stream nitrogen (N) loading on nitrous oxide (N2O) emissions from various of aquatic ecosystems are still unknown. In this study, direct measurements of water-air interface N2O exchange in different water bodies were conducted. Results showed that the water-air interface N2O exchange from tributaries, hydropower station reservoirs, a main stream, and its estuary were 10.14 ± 13.51, 15.64 ± 10.72, 27.59 ± 20.99, and 15.98 ± 12.26 µg N2O-N m(-2) h(-1), respectively, indicating the strong impacts of human activities on N2O emission rates. The water NO2 (-)-N values predicted the dissolved N2O concentrations better than did the NO3 (-)-N and NH4 (+)-N values, indicating strong denitrification and nitrification processes. The dissolved inorganic N explained 36 % of the variations in the N2O emissions for the whole river network.

  16. The Effect of Fuel Quality on Carbon Dioxide and Nitrogen Oxide Emissions, While Burning Biomass and RDF

    Science.gov (United States)

    Kalnacs, J.; Bendere, R.; Murasovs, A.; Arina, D.; Antipovs, A.; Kalnacs, A.; Sprince, L.

    2018-02-01

    The article analyses the variations in carbon dioxide emission factor depending on parameters characterising biomass and RDF (refuse-derived fuel). The influence of moisture, ash content, heat of combustion, carbon and nitrogen content on the amount of emission factors has been reviewed, by determining their average values. The options for the improvement of the fuel to result in reduced emissions of carbon dioxide and nitrogen oxide have been analysed. Systematic measurements of biomass parameters have been performed, by determining their average values, seasonal limits of variations in these parameters and their mutual relations. Typical average values of RDF parameters and limits of variations have been determined.

  17. A green fluorescent protein with photoswitchable emission from the deep sea.

    Directory of Open Access Journals (Sweden)

    Alexander Vogt

    Full Text Available A colorful variety of fluorescent proteins (FPs from marine invertebrates are utilized as genetically encoded markers for live cell imaging. The increased demand for advanced imaging techniques drives a continuous search for FPs with new and improved properties. Many useful FPs have been isolated from species adapted to sun-flooded habitats such as tropical coral reefs. It has yet remained unknown if species expressing green fluorescent protein (GFP-like proteins also exist in the darkness of the deep sea. Using a submarine-based and -operated fluorescence detection system in the Gulf of Mexico, we discovered ceriantharians emitting bright green fluorescence in depths between 500 and 600 m and identified a GFP, named cerFP505, with bright fluorescence emission peaking at 505 nm. Spectroscopic studies showed that approximately 15% of the protein bulk feature reversible ON/OFF photoswitching that can be induced by alternating irradiation with blue und near-UV light. Despite being derived from an animal adapted to essentially complete darkness and low temperatures, cerFP505 maturation in living mammalian cells at 37 degrees C, its brightness and photostability are comparable to those of EGFP and cmFP512 from shallow water species. Therefore, our findings disclose the deep sea as a potential source of GFP-like molecular marker proteins.

  18. Temperature dependence of fluorescence decay time and emission spectrum of bismuth germanate

    International Nuclear Information System (INIS)

    Melcher, C.L.; Liberman, A.; Schweitzer, J.S.; Simonetti, J.

    1985-01-01

    Bismuth germanate has become an increasingly popular replacement for NaI(Tl) scintillators in recent years, mainly due to its higher detection efficiency. However, its scintillation efficiency and fluorescence decay time are strongly temperature dependent. Optimum performance of detector systems which employ BGO crystals depends on knowledge of the BGO pulse shape and intensity and its emission spectrum at the operating temperature of the detector. Measurements of these quantities are presented over the temperature range -47 0 C to +111 0 C. Although the emission spectrum shifts only slightly over this temperature range, the scintillation efficiency and fluorescence decay time are strongly temperature dependent. In addition to the usefulness of these data for optimizing detector design, the results imply that luminescence quenching in BGO cannot be characterized by a single thermal activation to a radiationless transition but that a more complex model is required to characterize the light output from BGO crystals

  19. Experimental investigation of nitrogen based emissions from an ammonia fueled SI-engine

    DEFF Research Database (Denmark)

    Westlye, Fredrik Ree; Ivarsson, Anders; Schramm, Jesper

    2013-01-01

    . This causes the NO emissions to peak around 35% rather than 10% excess air, as is typical in HC fueled SI-engines. However the magnitude of NO emissions are comparable to that of measurements conducted with gasoline due to lower flame temperatures. Nitrogen dioxide levels are higher when comparing...... with gasoline, but has a relatively low share of the total NOx emissions (3-4%). Nitrous oxide is a product of NH2 reacting with NO 2 and NH reacting with NO. The magnitude is largely affected by ignition timing due to the temperature development during expansion and the amount of excess air, as increased...

  20. Fluorescence emissions from mixtures of Hg with the noble gases

    International Nuclear Information System (INIS)

    Woodworth, J.R.

    1977-01-01

    Fluorescence emissions from mixtures of Hg with high pressure Xe, Kr, and Ar (approx.1 torr Hg, 10 3 --10 4 torr noble gas) have been studied using a short-pulse relativistic electron beam as an excitation source. Hg--noble gas molecular bands were observed on the red sides of the Hg lines (1849 and 2537 A) as well as on the red sides of the Hg visible lines (7 3 S 1 →6 3 P 0 , 1 , 2 ). Temporal histories and production efficiencies of the molecular emissions were determined and a model was formulated for the time histories of the HgXe 2600 A bands. Possible applications to high power laser systems are discussed

  1. Fluorescent probes for "off-on" highly sensitive detection of Hg²⁺ and L-cysteine based on nitrogen-doped carbon dots.

    Science.gov (United States)

    Zhang, Yi; Cui, Peipei; Zhang, Feng; Feng, Xiaoting; Wang, Yaling; Yang, Yongzhen; Liu, Xuguang

    2016-05-15

    Fluorescent nitrogen-doped carbon dots (NCDs) were synthesized by a facile, and low-cost one-step hydrothermal strategy using citric acid as carbon source and ammonia solution as nitrogen source for the first time. The obtained NCDs show stable blue fluorescence with a high quantum yield of 35.4%, along with the fluorescence lifetime of ca. 6.75 ns. Most importantly, Hg(2+) can completely quench the fluorescence of NCDs as a result of the formation of a non-fluorescent stable NCDs-Hg(2+) complex. Static fluorescence quenching towards Hg(2+) is proved by the Stern-Volmer equation, ultraviolet-visible absorption spectra, temperature dependent quenching and fluorescence lifetime measurements. Subsequently, the fluorescence of the NCDs-Hg(2+) system is completely recovered with the addition L-cysteine (L-Cys) owing to the dissociation of NCDs-Hg(2+) complex to form a more stable Hg(2+)-L-Cys complex by Hg(2+)-S bonding. Therefore, such NCDs can be used as an effective fluorescent "turn-off" probe for rapid, rather highly selective and sensitive detection of Hg(2+), with a limit of detection (LOD) as low as 1.48 nM and a linear detection range of 0-10 μM. Interestingly, NCDs-Hg(2+) system can be conveniently employed as a fluorescent "turn-on" sensor for highly selective and sensitive detection of L-Cys with a low LOD of 0.79 nM and a wide linear detection range of 0-50 μM. Further, the sensitivity of NCDs to Hg(2+) is preserved in tap water with a LOD of 1.65 nM and a linear detection range of 0-10 μM. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. One-step synthesis of nitrogen-doped carbon nanodots for ratiometric pH sensing by femtosecond laser ablation method

    International Nuclear Information System (INIS)

    Xu, Huanhuan; Yan, Lihe; Nguyen, Vanthan; Yu, Yang; Xu, Yanmin

    2017-01-01

    Highlights: • Nitrogen-containing carbon nanodots (CDs) are synthesize using pulsed laser ablation in liquid. • The CDs show a strong fluorescence consisting of a dual-band luminescence peak. • The as prepared CDs can offer a ratiometric sensing platform for the detection the pH values. - Abstract: Nitrogen-doped carbon nanodots (CDs) are synthesized by one-step femtosecond laser ablation of graphite powder in aminotoluene at room temperature. The as-prepared CDs have the average diameter of 2.87 nm and possess an excitation-independent emission covering nearly the whole visible light region at a single excitation wavelength. The X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) analysis indicate that there are a huge number of multiple oxygen groups and amine groups on the surface of the CDs. As their different fluorescence peaks originated from different emission surface groups on the nanodots show different pH dependence, these CDs can be used for ratiometric pH sensing.

  3. One-step synthesis of nitrogen-doped carbon nanodots for ratiometric pH sensing by femtosecond laser ablation method

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Huanhuan [Key Laboratory for Physical Electronics and Devices of the Ministry of Education and Shaanxi Key Lab. of Information Photonic Technique, School of Electronics and Information Engineering, Xi’an Jiaotong University, Xi’an 710049 (China); Yan, Lihe, E-mail: liheyan@mail.xjtu.edu.cn [Key Laboratory for Physical Electronics and Devices of the Ministry of Education and Shaanxi Key Lab. of Information Photonic Technique, School of Electronics and Information Engineering, Xi’an Jiaotong University, Xi’an 710049 (China); Nguyen, Vanthan [Key Laboratory for Physical Electronics and Devices of the Ministry of Education and Shaanxi Key Lab. of Information Photonic Technique, School of Electronics and Information Engineering, Xi’an Jiaotong University, Xi’an 710049 (China); Le Quy Don Technical University, Hanoi 122314 (Viet Nam); Yu, Yang; Xu, Yanmin [Key Laboratory for Physical Electronics and Devices of the Ministry of Education and Shaanxi Key Lab. of Information Photonic Technique, School of Electronics and Information Engineering, Xi’an Jiaotong University, Xi’an 710049 (China)

    2017-08-31

    Highlights: • Nitrogen-containing carbon nanodots (CDs) are synthesize using pulsed laser ablation in liquid. • The CDs show a strong fluorescence consisting of a dual-band luminescence peak. • The as prepared CDs can offer a ratiometric sensing platform for the detection the pH values. - Abstract: Nitrogen-doped carbon nanodots (CDs) are synthesized by one-step femtosecond laser ablation of graphite powder in aminotoluene at room temperature. The as-prepared CDs have the average diameter of 2.87 nm and possess an excitation-independent emission covering nearly the whole visible light region at a single excitation wavelength. The X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) analysis indicate that there are a huge number of multiple oxygen groups and amine groups on the surface of the CDs. As their different fluorescence peaks originated from different emission surface groups on the nanodots show different pH dependence, these CDs can be used for ratiometric pH sensing.

  4. Quantifying fire severity, carbon, and nitrogen emissions in Alaska's boreal forest

    Science.gov (United States)

    Leslie A. Boby; Edward A.G. Schuur; Michelle C. Mack; David Verbyla; Jill F. Johnstone

    2010-01-01

    The boreal region stores a large proportion of the world's terrestrial carbon (C) and is subject to high-intensity, stand-replacing wildfires that release C and nitrogen (N) stored in biomass and soils through combustion. While severity and extent of fires drives overall emissions, methods for accurately estimating fire severity are poorly tested in this unique...

  5. THE REDSHIFT EVOLUTION OF OXYGEN AND NITROGEN ABUNDANCES IN EMISSION-LINE SDSS GALAXIES

    International Nuclear Information System (INIS)

    Thuan, Trinh X.; Pilyugin, Leonid S.; Zinchenko, Igor A.

    2010-01-01

    The oxygen and nitrogen abundance evolutions with redshift and galaxy stellar mass in emission-line galaxies from the Sloan Digital Sky Survey (SDSS) are investigated. This is the first such study for nitrogen abundances, and it provides an additional constraint for the study of the chemical evolution of galaxies. We have devised a criterion to recognize and exclude from consideration active galactic nuclei and star-forming galaxies with large errors in the line flux measurements. To select star-forming galaxies with accurate line fluxes measurements, we require that, for each galaxy, the nitrogen abundances derived with various calibrations based on different emission lines agree. Using this selection criterion, subsamples of star-forming SDSS galaxies have been extracted from catalogs of the Max-Planck-Institute for Astrophysics/Johns Hopkins University group. We found that the galaxies of highest masses, those with masses ∼>10 11.2 M sun , have not been enriched in both oxygen and nitrogen over the last ∼3 Gyr: they have formed their stars in the so distant past that these have returned their nucleosynthesis products to the interstellar medium before z = 0.25. The galaxies in the mass range from ∼10 11.0 M sun to ∼10 11.2 M sun do not show an appreciable enrichment in oxygen, but do show some enrichment in nitrogen: they also formed their stars before z = 0.25 but later in comparison to the galaxies of highest masses; these stars have not returned nitrogen to the interstellar medium before z = 0.25 because they have not had enough time to evolve. This suggests that stars with lifetimes of 2-3 Gyr, in the 1.5-2 M sun mass range, contribute to the nitrogen production. Finally, galaxies with masses ∼ 11 M sun show enrichment in both oxygen and nitrogen during the last 3 Gyr: they have undergone appreciable star formation and have converted up to ∼20% of their mass into stars over this period. Both oxygen and nitrogen enrichments increase with decreasing

  6. New dual emission fluorescent sensor for pH and Pb(II) based on bis(napfthalimide) derivative

    Energy Technology Data Exchange (ETDEWEB)

    Pina-Luis, Georgina, E-mail: gpinaluis@yahoo.com [Centro de Graduados e Investigacion en Quimica, Instituto Tecnologico de Tijuana, AP 1166, Tijuana 22500, BC (Mexico); Martinez-Quiroz, Marisela; Ochoa-Teran, Adrian [Centro de Graduados e Investigacion en Quimica, Instituto Tecnologico de Tijuana, AP 1166, Tijuana 22500, BC (Mexico); Santacruz-Ortega, Hisila [Departamento de investigacion en Polimeros y Materiales, Universidad de Sonora, Hermosillo, Sonora 83000 (Mexico); Mendez-Valenzuela, Eduardo [Centro de Graduados e Investigacion en Quimica, Instituto Tecnologico de Tijuana, AP 1166, Tijuana 22500, BC (Mexico)

    2013-02-15

    This paper describes a novel dual emission bis-1,8-naphthalimide sensor for selective determination of pH and Pb{sup 2+} ions. The influence of the variability in the backbone that links the two fluorophores (naphthalimides) as a function of pH and metal ions was studied by UV-visible and fluorescence spectroscopy. Compounds 1(a-d) with different length alkyl linkers (CH{sub 2}){sub n} (n=1, 2, 4 and 6) showed no excimer formation in aqueous solution. Fluorescence emission of these derivatives varied in a narrow range of pH (5-8) and was only slightly influenced by the addition of metal ions in CH{sub 3}CN solutions. However, derivative 1e with amino-containing spacer (CH{sub 2}-NH-CH{sub 2}) showed excimer emission in aqueous solution, a wide response to pH (2.5-9.5) and fluorescence enhancement with selective behavior towards metal ions. The pH sensor based in derivative 1e has a sufficient selectivity for practical pH monitoring in the presence of Li{sup +}, Na{sup +}, K{sup +}, Cs{sup +}, Ca{sup 2+}, Mg{sup 2+}, Ba{sup 2+}, Cu{sup 2+}, Pb{sup 2+}, Ni{sup 2+}, Zn{sup 2+} and Cd{sup 2+}. The coordination chemistry of these complexes was studied by UV-Vis, fluorescence and {sup 1}H NMR. This chemosensor displayed high selectivity fluorescence enhancement toward Pb{sup 2+} ions in the presence of the metals ions mentioned in CH{sub 3}CN solutions. Competitive assays show that a 1-fold of metal cations in each case, compared with Pb{sup 2+} ions, results in less than {+-}5% fluorescence intensity changes. Linear calibration up to 1 Multiplication-Sign 10{sup -5} M for Pb(II) ions (R=0.9968) was obtained and detection limit resulted of 5.0 Multiplication-Sign 10{sup -8} M. - Highlights: Black-Right-Pointing-Pointer A novel dual emission bis-1,8-naphthalimide sensor for pH and Pb{sup 2+} ions is synthetized. Black-Right-Pointing-Pointer The excimer formation depends on the spacer that links the two naphthalimide groups. Black-Right-Pointing-Pointer Bis

  7. Dynamic reallocation of marketable nitrogen emission permits in Danish freshwater aquaculture

    DEFF Research Database (Denmark)

    Nielsen, Rasmus; Andersen, Jesper Levring; Bogetoft, Peter

    2014-01-01

    farms are gradually introduced to the industry over 10 years. The new industry structure, production, and profitability gains are investigated, and the effect of changing the overall level of nitrogen emission is analyzed. Our results show that there is scope for a more efficient allocation of resources...... to either increase the production level or to reduce the emission level. This article adds to the literature by extending previous static reallocation models to a dynamic model, which allows for a gradual introduction of new firms. This makes it possible for managers to analyze the effects of reallocating...

  8. CN emission spectroscopy study of carbon plasma in nitrogen environment

    International Nuclear Information System (INIS)

    Abdelli-Messaci, S.; Kerdja, T.; Bendib, A.; Malek, S.

    2005-01-01

    Spectroscopic emission diagnostics of a carbon plasma created by an excimer KrF laser pulse at three laser fluences (12, 25 and 32 J/cm 2 ) is performed under nitrogen ambient at pressures of 0.5 and 1 mbar. By following the time evolution of the radical CN spectral emission profiles, we notice, at a certain distance from the target surface, the existence of twin peaks for the time of flight distribution. This double structure depends on laser fluence and gas pressure parameters. The first peak moves forward in relation with the plasma expansion whereas the second peak moves backward and it is attributed to CN species undergoing oscillations or reflected shocks

  9. Sample analysis using gamma ray induced fluorescent X-ray emission

    Energy Technology Data Exchange (ETDEWEB)

    Sood, B S; Allawadhi, K L; Gandhi, R; Batra, O P; Singh, N [Punjabi Univ., Patiala (India). Nuclear Science Labs.

    1983-01-01

    A non-destructive method for the analysis of materials using gamma ray-induced fluorescent x-ray emission has been developed. In this method, special preparation of very thin samples in which the absorption of the incident gamma rays and the emitted fluorescent x-rays is negligible, is not needed, and the absorption correction is determined experimentally. A suitable choice of the incident gamma ray energies is made to minimise enhancement effects through selective photoionization of the elements in the sample. The method is applied to the analysis of a typical sample of the soldering material using 279 keV and 59.5 keV gamma rays from /sup 203/Hg and /sup 241/Am radioactive sources respectively. The results of the analysis are found to agree well with those obtained from the chemical analysis.

  10. Efficiency of Cathodoluminescence Emission by Nitrogen-Vacancy Color Centers in Nanodiamonds.

    Science.gov (United States)

    Zhang, Huiliang; Glenn, David R; Schalek, Richard; Lichtman, Jeff W; Walsworth, Ronald L

    2017-06-01

    Correlated electron microscopy and cathodoluminescence (CL) imaging using functionalized nanoparticles is a promising nanoscale probe of biological structure and function. Nanodiamonds (NDs) that contain CL-emitting color centers are particularly well suited for such applications. The intensity of CL emission from NDs is determined by a combination of factors, including particle size, density of color centers, efficiency of energy deposition by electrons passing through the particle, and conversion efficiency from deposited energy to CL emission. This paper reports experiments and numerical simulations that investigate the relative importance of each of these factors in determining CL emission intensity from NDs containing nitrogen-vacancy (NV) color centers. In particular, it is found that CL can be detected from NV-doped NDs with dimensions as small as ≈40 nm, although CL emission decreases significantly for smaller NDs. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Corn nitrogen management influences nitrous oxide emissions in drained and undrained soils

    Science.gov (United States)

    Tile-drainage and nitrogen (N) fertilization are important for corn (Zea mays L.) production. To date, no studies have evaluated nitrous oxide (N2O) emissions of single vs. split-N fertilizer application under different soil drainage conditions. The objective of this study was to quantify season-lon...

  12. Functional imaging in bulk tissue specimens using optical emission tomography: fluorescence preservation during optical clearing

    International Nuclear Information System (INIS)

    Sakhalkar, H S; Dewhirst, M; Oliver, T; Cao, Y; Oldham, M

    2007-01-01

    Optical emission computed tomography (optical-ECT) is a technique for imaging the three-dimensional (3D) distribution of fluorescent probes in biological tissue specimens with high contrast and spatial resolution. In optical-ECT, functional information can be imaged by (i) systemic application of functional labels (e.g. fluorophore labelled proteins) and/or (ii) endogenous expression of fluorescent reporter proteins (e.g. red fluorescent protein (RFP), green fluorescent protein (GFP)) in vivo. An essential prerequisite for optical-ECT is optical clearing, a procedure where tissue specimens are made transparent to light by sequential perfusion with fixing, dehydrating and clearing agents. In this study, we investigate clearing protocols involving a selection of common fixing (4% buffered paraformaldehyde (PFA), methanol and ethanol), dehydrating (methanol and ethanol) and clearing agents (methyl salicylate and benzyl-alcohol-benzyl-benzoate (BABB)) in order to determine a 'fluorescence friendly' clearing procedure. Cell culture experiments were employed to optimize the sequence of chemical treatments that best preserve fluorescence. Texas red (TxRed), fluorescein isothiocyanate (FITC), RFP and GFP were tested as fluorophores and fluorescent reporter proteins of interest. Fluorescent and control cells were imaged on a microscope using a DSred2 and FITC filter set. The most promising clearing protocols of cell culture experiments were applied to whole xenograft tumour specimens, to test their effectiveness in large unsectioned samples. Fluorescence of TxRed/FITC fluorophores was not found to be significantly affected by any of the test clearing protocols. RFP and GFP fluorescence, however, was found to be significantly greater when cell fixation was in ethanol. Fixation in either PFA or methanol resulted in diminished fluorescence. After ethanol fixation, the RFP and GFP fluorescence proved remarkably robust to subsequent exposure to either methyl salicylate or BABB

  13. Functional imaging in bulk tissue specimens using optical emission tomography: fluorescence preservation during optical clearing

    Energy Technology Data Exchange (ETDEWEB)

    Sakhalkar, H S [Department of Radiation Oncology, Duke University Medical Center, Durham, NC 27710 (United States); Dewhirst, M [Department of Radiation Oncology, Duke University Medical Center, Durham, NC 27710 (United States); Oliver, T [Department of Cell Biology, Duke University Medical Center, Durham, NC 27710 (United States); Cao, Y [Department of Radiation Oncology, Duke University Medical Center, Durham, NC 27710 (United States); Oldham, M [Department of Radiation Oncology Physics, and Biomedical Engineering, Duke University Medical Center, Durham, NC 27710 (United States)

    2007-04-21

    Optical emission computed tomography (optical-ECT) is a technique for imaging the three-dimensional (3D) distribution of fluorescent probes in biological tissue specimens with high contrast and spatial resolution. In optical-ECT, functional information can be imaged by (i) systemic application of functional labels (e.g. fluorophore labelled proteins) and/or (ii) endogenous expression of fluorescent reporter proteins (e.g. red fluorescent protein (RFP), green fluorescent protein (GFP)) in vivo. An essential prerequisite for optical-ECT is optical clearing, a procedure where tissue specimens are made transparent to light by sequential perfusion with fixing, dehydrating and clearing agents. In this study, we investigate clearing protocols involving a selection of common fixing (4% buffered paraformaldehyde (PFA), methanol and ethanol), dehydrating (methanol and ethanol) and clearing agents (methyl salicylate and benzyl-alcohol-benzyl-benzoate (BABB)) in order to determine a 'fluorescence friendly' clearing procedure. Cell culture experiments were employed to optimize the sequence of chemical treatments that best preserve fluorescence. Texas red (TxRed), fluorescein isothiocyanate (FITC), RFP and GFP were tested as fluorophores and fluorescent reporter proteins of interest. Fluorescent and control cells were imaged on a microscope using a DSred2 and FITC filter set. The most promising clearing protocols of cell culture experiments were applied to whole xenograft tumour specimens, to test their effectiveness in large unsectioned samples. Fluorescence of TxRed/FITC fluorophores was not found to be significantly affected by any of the test clearing protocols. RFP and GFP fluorescence, however, was found to be significantly greater when cell fixation was in ethanol. Fixation in either PFA or methanol resulted in diminished fluorescence. After ethanol fixation, the RFP and GFP fluorescence proved remarkably robust to subsequent exposure to either methyl salicylate

  14. Moisture effects on carbon and nitrogen emission from burning of wildland biomass

    Directory of Open Access Journals (Sweden)

    L.-W. A. Chen

    2010-07-01

    Full Text Available Carbon (C and nitrogen (N released from biomass burning have multiple effects on the Earth's biogeochemical cycle, climate change, and ecosystem. These effects depend on the relative abundances of C and N species emitted, which vary with fuel type and combustion conditions. This study systematically investigates the emission characteristics of biomass burning under different fuel moisture contents, through controlled burning experiments with biomass and soil samples collected from a typical alpine forest in North America. Fuel moisture in general lowers combustion efficiency, shortens flaming phase, and introduces prolonged smoldering before ignition. It increases emission factors of incompletely oxidized C and N species, such as carbon monoxide (CO and ammonia (NH3. Substantial particulate carbon and nitrogen (up to 4 times C in CO and 75% of N in NH3 were also generated from high-moisture fuels, maily associated with the pre-flame smoldering. This smoldering process emits particles that are larger and contain lower elemental carbon fractions than soot agglomerates commonly observed in flaming smoke. Hydrogen (H/C ratio and optical properties of particulate matter from the high-moisture fuels show their resemblance to plant cellulous and brown carbon, respectively. These findings have implications for modeling biomass burning emissions and impacts.

  15. Preparation of polymer-rare earth complex using salicylic acid-containing polystyrene and its fluorescence emission property

    Energy Technology Data Exchange (ETDEWEB)

    Gao Baojiao, E-mail: gaobaojiao@126.com [Department of Chemical Engineering, North University of China, Taiyuan 030051 (China); Zhang Wei; Zhang Zhengguo; Lei Qingjuan [Department of Chemical Engineering, North University of China, Taiyuan 030051 (China)

    2012-08-15

    Salicylic acid (SA) was first bonded onto the side chains of polystyrene (PS), obtaining functional macromolecule SAPS. Using the salicylic acid-containing polystyrene as a macromolecular ligand, a polymer-rare earth complex, SAPS-Eu(III), was prepared. The structure of SAPS-Eu(III) was characterized, and the fluorescence properties of SAPS-Eu(III) were mainly investigated. The experimental results show that the complex SAPS-Eu(III) has fine chemical stability because of the bidentate chelating effect of salicylic acid ligand. More important, the ligand SA on the side chains of PS can strongly sensitize the fluorescence emission of the center ion, Eu{sup 3+} ion, and it enables the complex SAPS-Eu(III) to produce the apparent 'Antenna Effect'. In the diluted solution of the functional macromolecule SAPS, the formed complex SAPS-Eu(III) belongs to an intramolecular complex, or an intrachain complex. For the binary intramolecular complex SAPS-Eu(III), the apparent saturated coordination number of SA of SAPS towards Eu{sup 3+} ion is equal to 10, and here the binary intrachain complex SAPS-Eu(III) has the strongest fluorescence emission. On this basis, small-molecule 1,10-phenanthroline (Phen) acting as a co-ligand is added and the ternary complex SAPS-Eu(III)-Phen will be formed. As long as a small amount of Phen is added (in the molar ratio 1:1 (n(Phen):n(Eu))), the coordination of the two kinds of ligands, SA of SAPS and Phen, to Eu{sup 3+} ion will reach complete saturation, and here the fluorescence emission of the ternary complex will be further enhanced via the complementary coordination effect in comparison with that of the binary complex SAPS-Eu(III). - Highlights: Black-Right-Pointing-Pointer We prepared the functional polystyrene, SAPS, on whose side chain salicylic acid ligand was bonded. Black-Right-Pointing-Pointer The polymer-rare earth complex, SAPS-Eu(III), was prepared and a stronger 'antenna effect' was produced. Black

  16. Preparation of polymer–rare earth complex using salicylic acid-containing polystyrene and its fluorescence emission property

    International Nuclear Information System (INIS)

    Gao Baojiao; Zhang Wei; Zhang Zhengguo; Lei Qingjuan

    2012-01-01

    Salicylic acid (SA) was first bonded onto the side chains of polystyrene (PS), obtaining functional macromolecule SAPS. Using the salicylic acid-containing polystyrene as a macromolecular ligand, a polymer–rare earth complex, SAPS–Eu(III), was prepared. The structure of SAPS–Eu(III) was characterized, and the fluorescence properties of SAPS–Eu(III) were mainly investigated. The experimental results show that the complex SAPS–Eu(III) has fine chemical stability because of the bidentate chelating effect of salicylic acid ligand. More important, the ligand SA on the side chains of PS can strongly sensitize the fluorescence emission of the center ion, Eu 3+ ion, and it enables the complex SAPS–Eu(III) to produce the apparent “Antenna Effect”. In the diluted solution of the functional macromolecule SAPS, the formed complex SAPS–Eu(III) belongs to an intramolecular complex, or an intrachain complex. For the binary intramolecular complex SAPS–Eu(III), the apparent saturated coordination number of SA of SAPS towards Eu 3+ ion is equal to 10, and here the binary intrachain complex SAPS–Eu(III) has the strongest fluorescence emission. On this basis, small-molecule 1,10-phenanthroline (Phen) acting as a co-ligand is added and the ternary complex SAPS–Eu(III)–Phen will be formed. As long as a small amount of Phen is added (in the molar ratio 1:1 (n(Phen):n(Eu))), the coordination of the two kinds of ligands, SA of SAPS and Phen, to Eu 3+ ion will reach complete saturation, and here the fluorescence emission of the ternary complex will be further enhanced via the complementary coordination effect in comparison with that of the binary complex SAPS–Eu(III). - Highlights: ► We prepared the functional polystyrene, SAPS, on whose side chain salicylic acid ligand was bonded. ► The polymer-rare earth complex, SAPS–Eu(III), was prepared and a stronger “antenna effect” was produced. ► For the intramolecular complex SAPS–Eu(III), the apparent

  17. Modeling of carbon and nitrogen gaseous emissions from cattle manure compost windrows

    Science.gov (United States)

    Windrow composting of cattle manure is a significant source of gaseous emissions, which include ammonia (NH3) and the greenhouse gases (GHGs) of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). A manure compost model was developed to simulate carbon (C) and nitrogen (N) processes includ...

  18. Fluorescence imaging of soybean flavonol isolines

    Science.gov (United States)

    Kim, Moon S.; Lee, Edward H.; Mulchi, Charles L.; McMurtrey, James E., III; Chappelle, Emmett W.; Rowland, Randy A.

    1998-07-01

    Experiments were conducted to characterize the fluorescence emission of leaves from four soybean ('Harosoy') plants containing different concentrations of flavonols (kaempferol glycosides). The investigation utilized genetically mutated soybean flavonol isolines grown in a constant environment, thus limiting factors known to affect fluorescence emission characteristics other than different kaempferol glycosides concentrations. Flavonol isolines included OX922, OX941, OX942, OX944. The first two isolines contain kaempferol (K) glycosides; K3, K6, and K9, and the latter two did not have K3, K6, and K9. A fluorescence imaging system (FIS) was used to characterize steady state florescence images of the sample leaves measured at wavelengths centered at 450, 550, 680, and 740 nm with an excitation at 360 nm. Images taken with FIS greatly complement non-imaging fluorescence measurements by characterizing the spatial variation of fluorescence within leaves. We also acquired fluorescence emission spectra to characterize spectral features of the soybean flavonol isolines. The emission spectral shape of the fluorescence emission characteristics were not significantly different between the soybeans that contain kaempferol glycosides and the ones that do not contain kaempferol glycosides. Typical emission maxima of green vegetation in the blue, green, red, and far-red bands were noticed in all four soybean isolines. However, plants containing kaempferol glycosides, OX922 and OX941 had significantly lower intensities throughout the wavelength regions. These results imply that fluorescence emission intensities in the fluorescence emission bands studied are significantly affected by the presence and absence of kaempferol glycosides concentrations (UV radiation screening compounds). Pure kaempferol glycoside dissolved in solution show minimal fluorescence emission when excited with the absorption maximum radiation at 365 nm. However, a broad band emission can be seen in the green

  19. Super-resolution from single photon emission: toward biological application

    Science.gov (United States)

    Moreva, E.; Traina, P.; Forneris, J.; Ditalia Tchernij, S.; Guarina, L.; Franchino, C.; Picollo, F.; Ruo Berchera, I.; Brida, G.; Degiovanni, I. P.; Carabelli, V.; Olivero, P.; Genovese, M.

    2017-08-01

    Properties of quantum light represent a tool for overcoming limits of classical optics. Several experiments have demonstrated this advantage ranging from quantum enhanced imaging to quantum illumination. In this work, experimental demonstration of quantum-enhanced resolution in confocal fluorescence microscopy will be presented. This is achieved by exploiting the non-classical photon statistics of fluorescence emission of single nitrogen-vacancy (NV) color centers in diamond. By developing a general model of super-resolution based on the direct sampling of the kth-order autocorrelation function of the photoluminescence signal, we show the possibility to resolve, in principle, arbitrarily close emitting centers. Finally, possible applications of NV-based fluorescent nanodiamonds in biosensing and future developments will be presented.

  20. A Far-ultraviolet Fluorescent Molecular Hydrogen Emission Map of the Milky Way Galaxy

    Energy Technology Data Exchange (ETDEWEB)

    Jo, Young-Soo; Min, Kyoung-Wook [Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon, 305-701 (Korea, Republic of); Seon, Kwang-Il; Han, Wonyong [Korea Astronomy and Space Science Institute (KASI), 776 Daedeokdae-ro, Yuseong-gu, Daejeon, 305-348 (Korea, Republic of); Edelstein, Jerry, E-mail: stspeak@gmail.com [Space Sciences Laboratory, University of California, Berkeley, CA, 94720 (United States)

    2017-08-01

    We present the far-ultraviolet (FUV) fluorescent molecular hydrogen (H{sub 2}) emission map of the Milky Way Galaxy obtained with FIMS/SPEAR covering ∼76% of the sky. The extinction-corrected intensity of the fluorescent H{sub 2} emission has a strong linear correlation with the well-known tracers of the cold interstellar medium (ISM), including color excess E(B–V) , neutral hydrogen column density N (H i), and H α emission. The all-sky H{sub 2} column density map was also obtained using a simple photodissociation region model and interstellar radiation fields derived from UV star catalogs. We estimated the fraction of H{sub 2} ( f {sub H2}) and the gas-to-dust ratio (GDR) of the diffuse ISM. The f {sub H2} gradually increases from <1% at optically thin regions where E(B–V) < 0.1 to ∼50% for E(B–V)  = 3. The estimated GDR is ∼5.1 × 10{sup 21} atoms cm{sup −2} mag{sup −1}, in agreement with the standard value of 5.8 × 10{sup 21} atoms cm{sup −2} mag{sup −1}.

  1. Development of photosynthetic activity in Porphyridium purpureum (Rhodophyta) following nitrogen starvation

    Energy Technology Data Exchange (ETDEWEB)

    Levy, I.; Gantt, E. (Smithsonian Institution, Washington, DC (USA))

    1990-03-01

    The effects of nitrogen limitation on laboratory cultures of Porphyridium purpureum Bory, Drew and Ross were studied under continuous white light illumination (35 {mu}E {times} m{sup {minus}2} {times} s{sup {minus}1}). Growth ceased, respiration exceeded photosynthesis, chlorophyll content was reduced by 80%, and phycoerythrin content was reduced by 99% over a period of 14 days under nitrogen limitation. Recovery upon addition of nitrogen resulted in increased phycobiliprotein content, appearance of phycobilisomes attached to the thylakoids, increased oxygen evolution, and increased fluorescence emission from photosystem 1 (720 nm) and photosystem 2 (685 nm) upon excitation by green light. Growth resumes after 72 h and was concomitant with an increase of chlorophyll, phycoerythrin and phycobilisomes per thylakoid area. The results suggest that photosystem 1 was less affected by nitrogen starvation than photosystem 2 and that the recovery was largely dependent on the restoration of phycobilisomes and other photosystem components.

  2. 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)

  3. 40 CFR 62.14103 - Emission limits for municipal waste combustor metals, acid gases, organics, and nitrogen oxides.

    Science.gov (United States)

    2010-07-01

    ... combustor metals, acid gases, organics, and nitrogen oxides. 62.14103 Section 62.14103 Protection of... combustor metals, acid gases, organics, and nitrogen oxides. (a) The emission limits for municipal waste combustor metals are specified in paragraphs (a)(1) through (a)(3) of this section. (1) The owner or...

  4. Spatial variability of oceanic phycoerythrin spectral types derived from airborne laser-induced fluorescence emissions

    Science.gov (United States)

    Hoge, Frank E.; Wright, C. Wayne; Kana, Todd M.; Swift, Robert N.; Yungel, James K.

    1998-07-01

    We report spatial variability of oceanic phycoerythrin spectral types detected by means of a blue spectral shift in airborne laser-induced fluorescence emission. The blue shift of the phycoerythrobilin fluorescence is known from laboratory studies to be induced by phycourobilin chromophore substitution at phycoerythrobilin chromophore sites in some strains of phycoerythrin-containing marine cyanobacteria. The airborne 532-nm laser-induced phycoerythrin fluorescence of the upper oceanic volume showed distinct segregation of cyanobacterial chromophore types in a flight transect from coastal water to the Sargasso Sea in the western North Atlantic. High phycourobilin levels were restricted to the oceanic (oligotrophic) end of the flight transect, in agreement with historical ship findings. These remotely observed phycoerythrin spectral fluorescence shifts have the potential to permit rapid, wide-area studies of the spatial variability of spectrally distinct cyanobacteria, especially across interfacial regions of coastal and oceanic water masses. Airborne laser-induced phytoplankton spectral fluorescence observations also further the development of satellite algorithms for passive detection of phytoplankton pigments. Optical modifications to the NASA Airborne Oceanographic Lidar are briefly described that permitted observation of the fluorescence spectral shifts.

  5. Suppression of nitrogen oxides emission by carbonaceous reductants

    International Nuclear Information System (INIS)

    Tomita, A.

    2001-01-01

    The present status of NO x emission from power stations and automobiles is first summarized, and the controlling regulations in respective areas are reviewed. In spite of much progress, we have to further reduce the NO x emission in all the areas. In order to develop more effective technology, the fundamental understanding of the relevant reactions is essential. The heterogeneous reactions, like NO x and N 2 O formation from coal char, NO x and N 2 O reduction with carbon, and NO x reduction with hydrocarbon gases over heterogeneous catalysts are not well understood yet. This paper briefly summarizes our recent studies on the heterogeneous reactions of NO x formation and destruction. The importance of surface nitrogen species is emphasized in all the reaction systems. The presence of such surface species plays a very important role, not only in NO x destruction on carbon surfaces, but also in the NO x release during coal char combustion. Finally, future research areas are identified, where we need to understand what actually happens under high-temperature reaction conditions

  6. Phosphorus, and nitrogen co-doped carbon dots as a fluorescent probe for real-time measurement of reactive oxygen and nitrogen species inside macrophages.

    Science.gov (United States)

    Gong, Yunqian; Yu, Bin; Yang, Wen; Zhang, Xiaoling

    2016-05-15

    Phosphorus and nitrogen doped carbon dots (PN-CDs) were conveniently prepared by carbonization of adenosine-5'-triphosphate using a hydrothermal treatment. The PN-CDs with P/C atomic ratio of ca. 9.2/100 emit blue luminescence with high quantum yields of up to 23.5%. The PN-CDs were used as a novel sensing platform for live cell imaging of reactive oxygen species (ROS) and reactive nitrogen species (RNS), including ClO(-), ONOO(-), and NO in macrophages. The nanosensor design is based on our new finding that the strong fluorescence of the PN-CDs can be sensitively and selectively quenched by ROS and RNS both in vitro and in vivo. These results reveal that the PN-CDs can serve as a sensitive sensor for rapid imaging of ROS and RNS signaling with high selectivity and contrast. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. A novel fluorescence biosensor for sensitivity detection of tyrosinase and acid phosphatase based on nitrogen-doped graphene quantum dots.

    Science.gov (United States)

    Qu, Zhengyi; Na, Weidan; Liu, Xiaotong; Liu, Hua; Su, Xingguang

    2018-01-02

    In this paper, we developed a sensitive fluorescence biosensor for tyrosinase (TYR) and acid phosphatase (ACP) activity detection based on nitrogen-doped graphene quantum dots (N-GQDs). Tyrosine could be catalyzed by TYR to generate dopaquinone, which could efficiently quench the fluorescence of N-GQDs, and the degree of fluorescence quenching of N-GQDs was proportional to the concentration of TYR. In the presence of ACP, l-Ascorbic acid-2-phosphate (AAP) was hydrolyzed to generate ascorbic acid (AA), and dopaquinone was reduced to l-dopa, resulting in the fluorescence recovery of the quenched fluorescence by dopaquinone. Thus, a novel fluorescence biosensor for the detection of TYR and ACP activity based on N-GQDs was constructed. Under the optimized experimental conditions, the fluorescence intensity was linearly correlated with the concentration of TYR and ACP in the range of 0.43-3.85 U mL -1 and 0.04-0.7 mU mL -1 with a detection limit of 0.15 U mL -1 and 0.014 mU mL -1 , respectively. The feasibility of the proposed biosensor in real samples assay was also studied and satisfactory results were obtained. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Reducing the emissions of nitrogen oxides when burning Kuznetsk bituminous coals

    Energy Technology Data Exchange (ETDEWEB)

    Kotler, V.R.

    1983-02-01

    Bituminous coals from the Kuzbass have a high nitrogen content. As a result, emissions of NO/SUB/x from power stations burning these coals frequently exceed the existing Standard. In order to reduce NO/SUB/x emissions tests were carried out using stage-wise combustion, supplying to the burners only part of the air required for complete combustion. The remaining air is supplied via tertiary nozzles situated about 14 m above the burners. As a result of the tests, this method of combustion is recommended for low-sulphur Kuznetsk coals for all sub-critical boilers having dry-bottom furnaces. Extension to boilers with wet-bottom furnaces and to supercritical boilers requires further investigation.

  9. Discriminative detection of bivalent Cu by dual-emission ZnSe quantum dot fluorescence sensing via ratiometric fluorescence measurements

    International Nuclear Information System (INIS)

    Wang, Chunlei; Zhou, Shujie; Xu, Shuhong; Wang, Zhuyuan; Cui, Yiping

    2014-01-01

    In this work, we showed that 1-thioglycerol (TG)-capped ZnSe quantum dots (QDs) with dual-emission could perform ideal QD fluorescence sensing for ratiometric fluorescence measurements. By comparing the fluorescence ratios at two emission peaks before and after the addition of cations, the discriminative detection of Cu(II) was realized, even in the case of co-existing with large amounts of other sensitive cations, such as Ag(I). The discriminative detection of Cu(II) is accurate with co-existing Ag(I) below 10 μmol L −1 . By a joint investigation of the ionic diffuse dynamics and carrier recombination dynamics, we found that the adsorbed layer of QDs plays a key role in the discriminative detection of Cu(II) from Ag(I) or other sensitive cations. The moderate adsorption capacity with a QD adsorbed layer makes Cu(II) capable of travelling across the QD double-layer structure, following a surface doping process via chemical reactions between Cu(II) and the QD surface atoms. As a result of Cu(II) doping, there were three major carrier recombination channels: the non-radiation recombination between the QD conduction band to the Cu(II) energy level, together with the non-radiation recombination and radiation recombination between the trap state energy levels and the Cu(II) energy level. As for Ag(I) and other sensitive cations, they have a strong adsorption capacity with the QD adsorbed layer, making them mainly present on the adsorbed layer. Due to the blocking of the ligand layer, we only observed weak coupling of the ZnSe conduction band with the Ag(I) energy level via a non-radiation recombination channel. (paper)

  10. Constraining Microwave Emission from Extensive Air Showers via the MIDAS Experiment

    Science.gov (United States)

    Richardson, Matthew; Privitera, Paolo

    2017-01-01

    Ultra high energy cosmic rays (UHECRs) are accelerated by the most energetic processes in the universe. Upon entering Earth’s atmosphere they produce particle showers known as extensive air showers (EASs). Observatories like the Pierre Auger Observatory sample the particles and light produced by the EASs through large particle detector arrays or nitrogen fluorescence detectors to ascertain the fundamental properties of UHECRs. The large sample of high quality data provided by the Pierre Auger Observatory can be attributed to the hybrid technique which utilizes the two aforementioned techniques simultaneously; however, the limitation of only being able to observe nitrogen fluorescence from EASs on clear moonless nights yields a limited 10% duty cycle for the hybrid technique. One proposal for providing high quality data at increased statistics is the observation of isotropic microwave emission from EASs, as such emission would be observed with a 100% duty cycle. Measurements of microwave emission from laboratory air plasmas conducted by Gorham et al. (2008) produced promising results indicating that the microwave emission should be observable using inexpensive detectors. The Microwave Detection of Air Showers (MIDAS) experiment was built at the University of Chicago to characterize the isotropic microwave emission from EASs and has collected 359 days of observational data at the location of the Pierre Auger experiment. We have performed a time coincidence analysis between this data and data from Pierre Auger and we report a null result. This result places stringent limits on microwave emission from EASs and demonstrates that the laboratory measurements of Gorham et al. (2008) are not applicable to EASs, thus diminishing the feasibility of using isotropic microwave emission to detect EASs.

  11. Reduced Fluorescent Protein Switching Fatigue by Binding-Induced Emissive State Stabilization

    Directory of Open Access Journals (Sweden)

    Thijs Roebroek

    2017-09-01

    Full Text Available Reversibly switchable fluorescent proteins (RSFPs enable advanced fluorescence imaging, though the performance of this imaging crucially depends on the properties of the labels. We report on the use of an existing small binding peptide, named Enhancer, to modulate the spectroscopic properties of the recently developed rsGreen series of RSFPs. Fusion constructs of Enhancer with rsGreen1 and rsGreenF revealed an increased molecular brightness and pH stability, although expression in living E. coli or HeLa cells resulted in a decrease of the overall emission. Surprisingly, Enhancer binding also increased off-switching speed and resistance to switching fatigue. Further investigation suggested that the RSFPs can interconvert between fast- and slow-switching emissive states, with the overall protein population gradually converting to the slow-switching state through irradiation. The Enhancer modulates the spectroscopic properties of both states, but also preferentially stabilizes the fast-switching state, supporting the increased fatigue resistance. This work demonstrates how the photo-physical properties of RSFPs can be influenced by their binding to other small proteins, which opens up new horizons for applications that may require such modulation. Furthermore, we provide new insights into the photoswitching kinetics that should be of general consideration when developing new RSFPs with improved or different photochromic properties.

  12. High-performance hybrid white organic light-emitting devices without interlayer between fluorescent and phosphorescent emissive regions.

    Science.gov (United States)

    Sun, Ning; Wang, Qi; Zhao, Yongbiao; Chen, Yonghua; Yang, Dezhi; Zhao, Fangchao; Chen, Jiangshan; Ma, Dongge

    2014-03-12

    By using mixed hosts with bipolar transport properties for blue emissive layers, a novel phosphorescence/fluorescence hybrid white OLED without using an interlayer between the fluorescent and phosphorescent regions is demonstrated. The peak EQE of the device is 19.0% and remains as high as 17.0% at the practical brightness of 1000 cd m(-2) . © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Measurement of undisturbed di-nitrogen emissions from aquatic ecosystems

    Science.gov (United States)

    Qin, Shuping, Clough, Timothy, Lou, Jiafa; Hu, Chunsheng; Oenema, Oene; Wrage-Mönnig, Nicole; Zhang, Yuming

    2016-04-01

    Increased production of reactive nitrogen (Nr) from atmospheric di-nitrogen (N2) during the last century has greatly contributed to increased food production1-4. However, enriching the biosphere with Nr through N fertilizer production, combustion, and biological N2 fixation has also caused a series of negative effects on global ecosystems 5,6, especially aquatic ecosystems7. The main pathway converting Nr back into the atmospheric N2 pool is the last step of the denitrification process, i.e., the reduction of nitrous oxide (N2O) into N2 by micro-organisms7,8. Despite several attempts9,10, there is not yet an accurate, fast and direct method for measuring undisturbed N2 fluxes from denitrification in aquatic sediments at the field scale11-14. Such a method is essential to study the feedback of aquatic ecosystems to Nr inputs1,2,7. Here we show that the measurement of both N2O emission and its isotope signature can be used to infer the undisturbed N2 fluxes from aquatic ecosystems. The microbial reduction of N2O increases the natural abundance of 15N-N2O relative to 14N-N2O (δ15N-N2O). We observed linear relationships between δ15N-N2O and the logarithmic transformed N2O/(N2+N2O) emission ratios. Through independent measurements, we verified that the undisturbed N2 flux from aquatic ecosystems can be inferred from measurements of N2O emissions and the δ15N-N2O signature. Our method allows the determination of field-scale N2 fluxes from undisturbed aquatic ecosystems, and thereby allows model predictions of denitrification rates to be tested. The undisturbed N2 fluxes observed are almost one order of magnitude higher than those estimated by the traditional method, where perturbation of the system occurs, indicating that the ability of aquatic ecosystems to remove Nr may have been severely underestimated.

  14. Ag-protein plasmonic architectures for surface plasmon-coupled emission enhancements and Fabry-Perot mode-coupled directional fluorescence emission

    Science.gov (United States)

    Badiya, Pradeep Kumar; Patnaik, Sai Gourang; Srinivasan, Venkatesh; Reddy, Narendra; Manohar, Chelli Sai; Vedarajan, Raman; Mastumi, Noriyoshi; Belliraj, Siva Kumar; Ramamurthy, Sai Sathish

    2017-10-01

    We report the use of silver decorated plant proteins as spacer material for augmented surface plasmon-coupled emission (120-fold enhancement) and plasmon-enhanced Raman scattering. We extracted several proteins from different plant sources [Triticum aestivum (TA), Aegle marmelos (AM), Ricinus communis (RC), Jatropha curcas (JC) and Simarouba glauca (SG)] followed by evaluation of their optical properties and simulations to rationalize observed surface plasmon resonance. Since the properties exhibited by protein thin films is currently gaining research interest, we have also carried out simulation studies with Ag-protein biocomposites as spacer materials in metal-dielectric-metal planar microcavity architecture for guided emission of Fabry-Perot mode-coupled fluorescence.

  15. N2O emissions due to nitrogen fertilizer applications in two regions of sugarcane cultivation in Brazil

    International Nuclear Information System (INIS)

    Signor, D; Cerri, C E P; Conant, R

    2013-01-01

    Among the main greenhouse gases (CO 2 , CH 4 and N 2 O), N 2 O has the highest global warming potential. N 2 O emission is mainly connected to agricultural activities, increasing as nitrogen concentrations increase in the soil with nitrogen fertilizer application. We evaluated N 2 O emissions due to application of increasing doses of ammonium nitrate and urea in two sugarcane fields in the mid-southern region of Brazil: Piracicaba (São Paulo state) and Goianésia (Goiás state). In Piracicaba, N 2 O emissions exponentially increased with increasing N doses and were similar for urea and ammonium nitrate up to a dose of 107.9 kg ha −1 of N. From there on, emissions exponentially increased for ammonium nitrate, whereas for urea they stabilized. In Goianésia, N 2 O emissions were lower, although the behavior was similar to that at the Piracicaba site. Ammonium nitrate emissions increased linearly with N dose and urea emissions were adjusted to a quadratic equation with a maximum amount of 113.9 kg N ha −1 . This first effort to measure fertilizer induced emissions in Brazilian sugarcane production not only helps to elucidate the behavior of N 2 O emissions promoted by different N sources frequently used in Brazilian sugarcane fields but also can be useful for future Brazilian ethanol carbon footprint studies. (letter)

  16. The Emission, Lifetimes, and Formation Threshold of the Vegard-Kaplan Transition of Solid Nitrogen Exposed to Far-ultraviolet Radiation

    Science.gov (United States)

    Lu, Hsiao-Chi; Lo, Jen-Iu; Peng, Yu-Chain; Chou, Sheng-Lung; Lin, Meng-Yeh; Cheng, Bing-Ming

    2016-11-01

    Irradiation of solid nitrogen at 4 K with far-ultraviolet light from a synchrotron caused excitation to the upper state of the Vegard-Kaplan (VK) system; the emission in that system was simultaneously recorded in wavelength region 200-440 nm. The lifetimes of emission lines for VK (0, 1) to (0, 12) transitions were measured in the range of 2.12 ˜ 2.65 s. The threshold wavelength to observe the VK emission was 175.0 ± 3.5 nm, corresponding to energy 7.08 ± 0.14 eV. This investigation of the generation of icy VK nitrogen enhances our understanding of its photochemistry in space.

  17. THE EMISSION, LIFETIMES, AND FORMATION THRESHOLD OF THE VEGARD–KAPLAN TRANSITION OF SOLID NITROGEN EXPOSED TO FAR-ULTRAVIOLET RADIATION

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Hsiao-Chi; Lo, Jen-Iu; Peng, Yu-Chain; Chou, Sheng-Lung; Lin, Meng-Yeh; Cheng, Bing-Ming, E-mail: bmcheng@nsrrc.org.tw [National Synchrotron Radiation Research Center, No. 101, Hsin-Ann Road, Hsinchu Science Park, Hsinchu 30076, Taiwan (China)

    2016-11-20

    Irradiation of solid nitrogen at 4 K with far-ultraviolet light from a synchrotron caused excitation to the upper state of the Vegard–Kaplan (VK) system; the emission in that system was simultaneously recorded in wavelength region 200–440 nm. The lifetimes of emission lines for VK (0, 1) to (0, 12) transitions were measured in the range of 2.12 ∼ 2.65 s. The threshold wavelength to observe the VK emission was 175.0 ± 3.5 nm, corresponding to energy 7.08 ± 0.14 eV. This investigation of the generation of icy VK nitrogen enhances our understanding of its photochemistry in space.

  18. THE EMISSION, LIFETIMES, AND FORMATION THRESHOLD OF THE VEGARD–KAPLAN TRANSITION OF SOLID NITROGEN EXPOSED TO FAR-ULTRAVIOLET RADIATION

    International Nuclear Information System (INIS)

    Lu, Hsiao-Chi; Lo, Jen-Iu; Peng, Yu-Chain; Chou, Sheng-Lung; Lin, Meng-Yeh; Cheng, Bing-Ming

    2016-01-01

    Irradiation of solid nitrogen at 4 K with far-ultraviolet light from a synchrotron caused excitation to the upper state of the Vegard–Kaplan (VK) system; the emission in that system was simultaneously recorded in wavelength region 200–440 nm. The lifetimes of emission lines for VK (0, 1) to (0, 12) transitions were measured in the range of 2.12 ∼ 2.65 s. The threshold wavelength to observe the VK emission was 175.0 ± 3.5 nm, corresponding to energy 7.08 ± 0.14 eV. This investigation of the generation of icy VK nitrogen enhances our understanding of its photochemistry in space.

  19. Effects of Corn Straw Returning and Nitrogen Fertilizer Application Methods on N2O Emission from Wheat Growing Season

    Directory of Open Access Journals (Sweden)

    XU Yu

    2015-12-01

    Full Text Available Based on a wheat field experiment, the effect of four treatments such as no-straw returning (SN, straw returning (SR, control release fertilizer application(SRC and nitrogen drilling(SRR on N2O emission was studied using the static chamber method and the gas chromatographic technique. The results indicated that the wheat field was the sources of N2O emission. The N2O emission peaks followed each time of fertilizer application and irrigation, and usually continued for 1~2 weeks. N2O emissions accounted for more than 40% of total emissions during the N2O emission peak. The amount of N2O emission during three growing stage of wheat from high to low was arranged in turn pre-wintering period, post-wintering period and wintering period. N2O emission could be increased by straw returning. Compared with SN, N2O emission could be enhanced by 48.6% under SR. Both SRC and SRR could decrease the N2O emission, increase wheat yield and economic benefit, especially the latter. Nitrogen drilling is a good method for yield increment and N2O abatement.

  20. Carbon-dot-based dual-emission silica nanoparticles as a ratiometric fluorescent probe for vanadium(V) detection in mineral water samples

    Science.gov (United States)

    He, Lijun; Zhang, Heng; Fan, Huanhuan; Jiang, Xiuming; Zhao, Wenjie; Xiang, Guo Qiang

    2018-01-01

    Herein, we propose a simple and effective strategy for designing a ratiometric fluorescent nanosensor. We designed and developed a carbon dots (CDs) based dual-emission nanosensor for vanadium(V) by coating the surface of dye-doped silica nanoparticles with CDs. The fluorescence of dual-emission silica nanoparticles was quenched in acetic acid through potassium bromate (KBrO3) oxidation. V(V) could catalyze KBrO3 oxidation reaction process, resulting in the ratiometric fluorescence quenching of dual-emission silica nanoparticles. We investigated several important parameters affecting the performance of the nanosensor. Under the optimized conditions, the detection limit of this nanosensor reached 1.1 ng mL- 1 and the linear range from 10 to 800 ng mL- 1. Furthermore, we found that the sensor was suitable for determination of V(V) in different mineral water samples with satisfactory results.

  1. Fluorescence spectroscopy for medical and environmental diagnostics

    International Nuclear Information System (INIS)

    Johansson, Jonas.

    1993-09-01

    Fluorescence spectroscopy can be used for diagnostics in medical and environmental applications. The many aspects of fluorescence emission are utilized to enhance the accuracy of the diagnosis. A fluorescence detection system, based on nitrogen laser or dye laser excitation and optical multichannel detection, was constructed, and fluorescence spectra from human malignant tumours of various origins, were recorded. Tumour demarcation was observed using exogenous chromophores, as well as the endogenous tissue fluorescence. In particular, δ-amino levulinic acid was found to provide very good tumour demarcation. A multi-colour imaging system capable of simultaneous recording of four fluorescence images at selected wavelengths, was developed. Examples of processed images, based on the four sub-images, are shown for malignant tumours. In addition, data from photodynamic treatment of human malignant tumours are presented. Autofluorescence spectra from excised pieces of human atherosclerotic aorta and atherosclerotic coronary segment were found to be different from those of non-diseased vessels. Furthermore, fluorescence decay curves from atherosclerotic samples were found to differ from those of non-diseased samples. It is concluded that both spectral and temporal information should be utilized to enhance the demarcation. Methods for obtaining fluorescence data free from interference from blood, with applications to in vivo laser angioplasty of atherosclerosis, are discussed. The optical multichannel system and the multi-colour imaging system were integrated with a remote sensing system, originally used for environmental measurements, to obtain fluorescence spectra as well as fluorescence images of plants at a distance of up to 100 m. The fluorescence data from plants subject to environmental stress or senescent plants were found to differ from those obtained from healthy vegetation. 359 refs

  2. Enhanced emission of nile red fluorescent nanoparticles embedded in hybrid sol-gel glasses.

    Science.gov (United States)

    Ferrer, Maria L; del Monte, Francisco

    2005-01-13

    Highly fluorescent Nile Red (NR) nanoparticles embedded in a hybrid sol-gel glass are reported. The crystallite growth within the confined system created by the porous hybrid matrix results in NR nanoparticles of averaged dimensions below 36 nm. The preparation process allows for the control of both the conformation adopted by single NR molecules prior to aggregation (e.g., near planar) and the configuration of the aggregates (e.g., oblique with phi architecture which ultimately forms the nanoparticles. The full preservation of the fluorescent configuration of the aggregates in the nanoparticles is confirmed through the application of the exciton theory, and it is responsible for the significant increase of the fluorescence emission intensity (e.g., up to 525- and 70-fold as compared to that obtained for single NR molecules embedded in pure and hybrid silica glasses, respectively).

  3. Mercury depletion as a way of changing the emission spectrum of a fluorescent lamp

    NARCIS (Netherlands)

    Bakker, L.P.; Kroesen, G.M.W.

    2000-01-01

    We present a promising option for changing the emission spectrum of a fluorescent lamp. In a neon/mercury discharge, neon radiation is produced when the mercury density is sufficiently low. Under certain discharge conditions, radial cathaphoresis causes depletion of mercury atoms in the center of

  4. Reduction of greenhouse gas emissions in the rape cultivation with special consideration of nitrogen fertilization; Minderung von Treibhausgasemissionen im Rapsanbau unter besonderer Beruecksichtigung der Stickstoffduengung

    Energy Technology Data Exchange (ETDEWEB)

    Heilmann, Hubert [Landesforschungsanstalt fuer Landwirtschaft und Fischerei Mecklenburg-Vorpommern, Guelzow-Pruezen (Germany). Inst. fuer Pflanzenproduktion und Betriebswirtschaft; Riemer, Doerte

    2017-08-01

    Involved into the research project ''Mitigation of greenhouse gas emissions in oilseed rape cropping with special consideration of nitrogen fertilizing'' regional specific GHG cropping emissions according to benchmark and regional experts are calculated by using a calculation method developed in cooperation with IFEU and according to IPCC (2006). The following results are achieved for 35 German NUTS2-regions: - nitrogen fertilization is the main influence for GHG emission reduction; - the use of low-emission nitrogen fertilizers is worth for GHG emission reduction; - without increasing the nutrient efficiency of organic fertilizers, GHG emission reductions are difficult to achieve in many regions; - GHG emission reduction/climate protection and realization of the WRRL or N-Saldo reduction come up to the same aim; - economic consequences of restrictive carbon mitigation can be compensated by slight price surcharges for certified raw material.

  5. Furnace devices aerodynamics optimization for fuel combustion efficiency improvement and nitrogen oxide emission reduction

    Science.gov (United States)

    Volkov, E. P.; Prokhorov, V. B.; Arkhipov, A. M.; Chernov, S. L.; Kirichkov, V. S.; Kaverin, A. A.

    2017-11-01

    MPEI conducts researches on physical and mathematical models of furnace chambers for improvement of power-generation equipment fuel combustion efficiency and ecological safety. Results of these researches are general principles of furnace aerodynamics arrangement for straight-flow burners and various fuels. It has been shown, that staged combustion arrangement with early heating and igniting with torch distribution in all furnace volume allows to obtain low carbon in fly ash and nitrogen oxide emission and also to improve boiler operation reliability with expand load adjustment range. For solid fuel combustion efficiency improvement it is practical to use high-placed and strongly down-tilted straight-flow burners, which increases high-temperature zone residence time for fuel particles. In some cases, for this combustion scheme it is possible to avoid slag-tap removal (STR) combustion and to use Dry-bottom ash removal (DBAR) combustion with tolerable carbon in fly ash level. It is worth noting that boilers with STR have very high nitrogen oxide emission levels (1200-1800 mg/m3) and narrow load adjustment range, which is determined by liquid slag output stability, so most industrially-developed countries don’t use this technology. Final decision about overhaul of boiler unit is made with regard to physical and mathematical modeling results for furnace and zonal thermal calculations for furnace and boiler as a whole. Overhaul of boilers to provide staged combustion and straight-flow burners and nozzles allows ensuring regulatory nitrogen oxide emission levels and corresponding best available technology criteria, which is especially relevant due to changes in Russian environmental regulation.

  6. A fluorescence probe based on the nitrogen-doped carbon dots prepared from orange juice for detecting Hg2+ in water

    International Nuclear Information System (INIS)

    Li, Zhili; Zhang, Ying; Niu, Qianqian; Mou, Mingyao; Wu, Yi; Liu, Xiaoxuan; Yan, Zhengyu; Liao, Shenghua

    2017-01-01

    An excellent biocompatible nitrogen-doped carbon dots (N-CDs) was successfully synthesized from orange juice and ethylenediamine by hydrothermal decomposition method. The as-prepared N-CDs were mono-dispersed spherical nanoparticles with a narrow size distribution of 0.5–3.0 nm and showed a good dispersion and stability in aqueous solution with the pH value ranging from 3.0 to 13.0. Photoluminescence spectra of as-prepared N-CDs demonstrated that the fluorescence intensity of N-CDs was increased with the doped nitrogen atoms and the FL-QY (fluorescence quantum yield) of N-CDs was up to 31.7%. Compared with Gly-CQDs(CQDs synthesied by Gly), which were prepared from chemical carbon source via hydrothermal decomposition method, the as-prepared N-CDs showed much lower cytotoxicity for Human THP-1 macrophage cells. These results indicated N-CDs prepared by our proposed method have excellent compatibility and more suitable for the application in biolabeling and bioimage. Due to the fluorescence quenching of N-CDs by mercury (II) ion (Hg 2+ ), a sensitive and selective method was developed for detecting Hg 2+ . The results indicated that the fluorescence intensity ratio of N-CDs was proportional to the concentration of Hg 2+ in the range from 4.0 μg/mL to 32.0 μg/mL and the recovery of spiked samples was ranged from 102.0% to 103.0%, which hinted our proposed method has a good sensitivity and accuracy and was suitable for detecting Hg 2+ with satisfactory in tap water.

  7. Gaseous Nitrogen Losses from Tropical Savanna Soils of Northern Australia: Dynamics, Controls and Magnitude of N2O, NO, and N2 emissions

    Science.gov (United States)

    Werner, C.; Hickler, T.; Hutley, L. B.; Butterbach-Bahl, K.

    2014-12-01

    Tropical savanna covers a large fraction of the global land area and thus may have a substantial effect on the global soil-atmosphere exchange of nitrogen. The pronounced seasonality of hygric conditions in this ecosystem affects strongly microbial process rates in the soil. As these microbial processes control the uptake, production, and release of nitrogen compounds, it is thought that this seasonality finally leads to strong temporal dynamics and varying magnitudes of gaseous losses to the atmosphere. However, given their areal extent and in contrast to other ecosystems, still few in-situ or laboratory studies exist that assess the soil-atmosphere exchange of nitrogen. We present laboratory incubation results from intact soil cores obtained from a natural savanna site in Northern Australia, where N2O, NO, and N2 emissions under controlled environmental conditions were investigated. Furthermore, in-situ measurements of high temporal resolution at this site recorded with automated static and dynamic chamber systems are discussed (N2O, NO). This data is then used to assess the performance of a process-based biogeochemical model (LandscapeDNDC), and the potential magnitude and dynamics of components of the site-scale nitrogen cycle where no measurements exist (biological nitrogen fixation and nitrate leaching). Our incubation results show that severe nutrient limitation of the soil only allows for very low N2O emissions (0.12 kg N ha-1 yr-1) and even a periodic N2O uptake. Annual NO emissions were estimated at 0.68 kg N ha-1 yr-1, while the release of inert nitrogen (N2) was estimated at 6.75 kg N ha-1 yr-1 (data excl. contribution by pulse emissions). We observed only minor N2O pulse emissions after watering the soil cores and initial rain events of the dry to wet season transition in-situ, but short-lived NO pulse emissions were substantial. Interestingly, some cores exhibited a very different N2O emission potential, indicating a substantial spatial variability of

  8. Dual emission fluorescent silver nanoclusters for sensitive detection of the biological coenzyme NAD+/NADH.

    Science.gov (United States)

    Yuan, Yufeng; Huang, Kehan; Chang, Mengfang; Qin, Cuifang; Zhang, Sanjun; Pan, Haifeng; Chen, Yan; Xu, Jianhua

    2016-02-01

    Fluorescent silver nanoclusters (Ag NCs) displaying dual-excitation and dual-emission properties have been developed for the specific detection of NAD(+) (nicotinamide adenine dinucleotide, oxidized form). With the increase of NAD(+) concentrations, the longer wavelength emission (with the peak at 550 nm) was gradually quenched due to the strong interactions between the NAD(+) and Ag NCs, whereas the shorter wavelength emission (peaking at 395 nm) was linearly enhanced. More important, the dual-emission intensity ratio (I395/I550), fitting by a single-exponential decay function, can efficiently detect various NAD(+) levels from 100 to 4000 μM, as well as label NAD(+)/NADH (reduced form of NAD) ratios in the range of 1-50. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. Charges on emissions of nitrogen oxides from forest industry boilers. Technical and economic effects

    International Nuclear Information System (INIS)

    Liebscher, P.

    1998-09-01

    The charges on nitrogen oxide emission have been introduced in order to create an incentive for the industry to reduce emissions. A high cost in unproductive investment for monitoring systems, SNCR and gas recirculation systems was paid. However, the economic burden for the industry was less than initially feared, since the NO x emissions were moderate for most of the boilers, and since the potential for reducing NO x by rather simple means could be exploited. Also, the NO x charges have created an objective for industry to optimize their boilers in a way that raises efficiency and availability, which is of greater value to the environment than the reduction of the already low NO x emissions from these boilers

  10. Nanodiamonds with silicon vacancy defects for nontoxic photostable fluorescent labeling of neural precursor cells.

    Science.gov (United States)

    Merson, Tobias D; Castelletto, Stefania; Aharonovich, Igor; Turbic, Alisa; Kilpatrick, Trevor J; Turnley, Ann M

    2013-10-15

    Nanodiamonds (NDs) containing silicon vacancy (SiV) defects were evaluated as a potential biomarker for the labeling and fluorescent imaging of neural precursor cells (NPCs). SiV-containing NDs were synthesized using chemical vapor deposition and silicon ion implantation. Spectrally, SiV-containing NDs exhibited extremely stable fluorescence and narrow bandwidth emission with an excellent signal to noise ratio exceeding that of NDs containing nitrogen-vacancy centers. NPCs labeled with NDs exhibited normal cell viability and proliferative properties consistent with biocompatibility. We conclude that SiV-containing NDs are a promising biomedical research tool for cellular labeling and optical imaging in stem cell research.

  11. Stimulated emission depletion microscopy resolves individual nitrogen vacancy centers in diamond nanocrystals.

    OpenAIRE

    Arroyo Camejo, S.; Adam, M.; Besbes, M.; Hugonin, J.; Jaques, V.; Greffet, J.; Roch, J.; Hell, S.; Treussart, F.

    2013-01-01

    Nitrogen-vacancy (NV) color centers in nanodiamonds are highly promising for bioimaging and sensing. However, resolving individual NV centers within nanodiamond particles and the controlled addressing and readout of their spin state has remained a major challenge. Spatially stochastic super-resolution techniques cannot provide this capability in principle, whereas coordinate-controlled super-resolution imaging methods, like stimulated emission depletion (STED) microscopy, have been predicted ...

  12. Fluorescence emission behavior of Eu(III) sorbed on calcium silicate hydrates as a secondary mineral formed without drying process

    International Nuclear Information System (INIS)

    Niibori, Yuichi; Narita, Masayuki; Chida, Taiji; Mimura, Hitoshi; Kirishima, Akira

    2014-01-01

    Calcium silicate hydrate (CSH) is a main component of cement-based material required for constructing the geological repository. As in many countries, since the repository in Japan is constructed below water table, we must consider the interaction of radionuclide with cement materials altered around the repository after the backfill. Using fluorescence emission spectra, so far, the authors have investigated the interaction of Eu(III) (as a chemical analog of Am(III)) with CSH gels as a secondary mineral formed without drying process, considering a condition saturated with groundwater. However, in such fluorescence emission behaviors, a deexcitation process of OH vibrators of light water and a quenching effect caused by Eu-Eu energy transfer between Eu atoms incorporated in the CSH gel must be considered. This study examined the fluorescence emission behavior of Eu(III) sorbed on CSH gels, by using La(III) (non-fluorescent ions) as a diluent of Eu(III). Furthermore, CSH samples were synthesized with CaO, SiO 2 , and heavy water (D 2 O) as a solvent in order to avoid the obvious deexcitation process of OH vibrators of light water. In the results, the peak around 618 nm was split into two peaks of 613 nm and 622 nm in the cases of Ca/Si=1.0 and 1.6. Then, the peak of 613 nm decreased with increment of Eu(III)/La(III) ratio. This means that the relative intensity of 613 nm is useful to quantify the amount of Eu(III) incorporated in CSH gel. Besides, the decay behavior of the fluorescence emission did not depend on the Eu/La concentration ratio. That is, such a quenching effect is neglectable. Additionally, the fluorescence emission spectra of Eu(III) showed that the state of Eu(III) depended on Ca/Si ratio of CSH. This suggested that there was several sites in CSH to incorporate Eu(III). When CSH is altered, whole cementitious material in repository must be altered forming cracks and leaching some calcium compositions. Therefore, the adsorptive capacity of CSH might

  13. Dietary protein affects nitrogen excretion and ammonia emission from slurry of growing-finishing pigs.

    NARCIS (Netherlands)

    Canh, T.T.; Aarnink, A.J.A.; Schutte, J.B.; Sutton, A.L.; Langhout, D.J.; Verstegen, M.W.A.

    1998-01-01

    The effects of dietary protein on nitrogen excretion and ammonia emission from slurry of growing–finishing pigs were studied both in vitro and in a pig house. The three diets had similar contents of NE, minerals, vitamins and ileal digestible lysine, methionine cystine, threonine and tryptophan, but

  14. Dietary protein affects nitrogen excretion and ammonia emission from slurry of growing-finishing pigs

    NARCIS (Netherlands)

    Canh, T.T.; Aarnink, A.J.A.; Schutte, J.B.; Sutton, A.; Langhout, D.J.; Verstegen, M.W.A.

    1998-01-01

    The effects of dietary protein on nitrogen excretion and ammonia emission from slurry of growing-finishing pigs were studied both in vitro and in a pig house. The three diets had similar contents of NE, minerals, vitamins and ileal digestible lysine, methionine + cystine, threonine and tryptophan,

  15. Satellite constraint for emissions of nitrogen oxides from anthropogenic, lightning and soil sources over East China on a high-resolution grid

    Directory of Open Access Journals (Sweden)

    J.-T. Lin

    2012-03-01

    Full Text Available Vertical column densities (VCDs of tropospheric nitrogen dioxide (NO2 retrieved from space provide valuable information to estimate emissions of nitrogen oxides (NOx inversely. Accurate emission attribution to individual sources, important both for understanding the global biogeochemical cycling of nitrogen and for emission control, remains difficult. This study presents a regression-based multi-step inversion approach to estimate emissions of NOx from anthropogenic, lightning and soil sources individually for 2006 over East China on a 0.25° long × 0.25° lat grid, employing the DOMINO product version 2 retrieved from the Ozone Monitoring Instrument. The inversion is done gridbox by gridbox to derive the respective emissions, taking advantage of differences in seasonality between anthropogenic and natural sources. Lightning and soil emissions are combined together for any given gridbox due to their similar seasonality; and their different spatial distributions are used implicitly for source separation to some extent. The nested GEOS-Chem model for East Asia is used to simulate the seasonal variations of different emission sources and impacts on VCDs of NO2 for the inversion purpose. Sensitivity tests are conducted to evaluate key assumptions embedded in the inversion process. The inverse estimate suggests annual budgets of about 7.1 TgN (±39%, 0.21 TgN (±61%, and 0.38 TgN (±65% for the a posteriori anthropogenic, lightning and soil emissions, respectively, about 18–23% higher than the respective a priori values. The enhancements in anthropogenic emissions are largest in cities and areas with extensive use of coal, particularly in the north in winter, as evident on the high-resolution grid. Derived soil emissions are consistent with recent bottom-up estimates. They are less than 6% of anthropogenic emissions annually, increasing to about 13% for July. Derived lightning emissions are about 3% of

  16. The influence of visible light and inorganic pigments on fluorescence excitation emission spectra of egg-, casein- and collagen-based painting media

    Science.gov (United States)

    Nevin, A.; Anglos, D.; Cather, S.; Burnstock, A.

    2008-07-01

    Spectrofluorimetric analysis of proteinaceous binding media is particularly promising because proteins employed in paintings are often fluorescent and media from different sources have significantly different fluorescence spectral profiles. Protein-based binding media derived from eggs, milk and animal tissue have been used for painting and for conservation, but their analysis using non-destructive techniques is complicated by interferences with pigments, their degradation and their low concentration. Changes in the fluorescence excitation emission spectra of films of binding media following artificial ageing to an equivalent of 50 and 100 years of museum lighting include the reduction of bands ascribed to tyrosine, tryptophan and Maillard reaction products and an increase in fluorescent photodegradation. Fluorescence of naturally aged paint is dependent on the nature of the pigment present and, with egg-based media, in comparison with un-pigmented films, emissions ascribed to amino acids are more pronounced.

  17. Fluorescence characteristics of the fuel tracers triethylamine and trimethylamine for the investigation of fuel distribution in internal combustion engines.

    Science.gov (United States)

    Lind, Susanne; Aßmann, Simon; Zigan, Lars; Will, Stefan

    2016-03-01

    Laser-induced fluorescence based on fuel tracers like amines is a suitable measurement technique for mixing studies in internal combustion (IC) engines. Triethylamine has often been used in gasoline IC engines; however, no detailed fluorescence characterization for excitation at 263 or 266 nm is available. Trimethylamine (TMA) exhibits high potential as a gaseous fuel tracer but little information about TMA fluorescence is currently available. A picosecond laser source combined with a streak camera equipped with a spectrograph was used to determine the spectral fluorescence emission and fluorescence decay time of both tracers. The tracers were investigated at various temperatures and pressures in a calibration cell with nitrogen as bath gas. The results provide an in-depth understanding of the fluorescence characteristics of both tracers and allow assessment of their application to the investigation of fuel distribution in IC engines.

  18. Multiphoton-Excited Fluorescence of Silicon-Vacancy Color Centers in Diamond

    Science.gov (United States)

    Higbie, J. M.; Perreault, J. D.; Acosta, V. M.; Belthangady, C.; Lebel, P.; Kim, M. H.; Nguyen, K.; Demas, V.; Bajaj, V.; Santori, C.

    2017-05-01

    Silicon-vacancy color centers in nanodiamonds are promising as fluorescent labels for biological applications, with a narrow, nonbleaching emission line at 738 nm. Two-photon excitation of this fluorescence offers the possibility of low-background detection at significant tissue depth with high three-dimensional spatial resolution. We measure the two-photon fluorescence cross section of a negatively charged silicon vacancy (Si -V- ) in ion-implanted bulk diamond to be 0.74 (19 )×10-50 cm4 s /photon at an excitation wavelength of 1040 nm. Compared to the diamond nitrogen-vacancy center, the expected detection threshold of a two-photon excited Si -V center is more than an order of magnitude lower, largely due to its much narrower linewidth. We also present measurements of two- and three-photon excitation spectra, finding an increase in the two-photon cross section with decreasing wavelength, and we discuss the physical interpretation of the spectra in the context of existing models of the Si -V energy-level structure.

  19. Dissolved organic carbon and nitrogen mineralization strongly affect co2 emissions following lime application to acidic soil

    International Nuclear Information System (INIS)

    Shaaban, M.; Peng, Q.; Lin, S.; Wu, Y.

    2014-01-01

    Emission of greenhouse gases from agricultural soils has main contribution to the climatic change and global warming. Dynamics of dissolved organic carbon (DOC) and nitrogen mineralization can affect CO/sub 2/ emission from soils. Influence of DOC and nitrogen mineralization on CO/sub 2/ emissions following lime application to acidic soil was investigated in current study. Laboratory experiment was conducted under aerobic conditions with 25% moisture contents (66% water-filled pore space) at 25 degree C in the dark conditions. Different treatments of lime were applied to acidic soil as follows: CK (control), L (low rate of lime: 0.2g lime / 100 g soil) and H (high rate of lime: 0.5g lime /100g soil). CO/sub 2/ emissions were measured by gas chromatography and dissolved organic carbon, NH4 +-N, NO/sub 3/ --N and soil pH were measured during incubation study. Addition of lime to acidic soil significantly increased the concentration of DOC and N mineralization rate. Higher concentrations of DOC and N mineralization, consequently, increased the CO/sub 2/ emissions from lime treated soils. Cumulative CO/sub 2/ emission was 75% and 71% higher from L and H treatments as compared to CK. The results of current study suggest that DOC and N mineralization are critical in controlling gaseous emissions of CO/sub 2/ from acidic soils following lime application. (author)

  20. Assessment of the environmental impacts and health benefits of a nitrogen emission control area in the North Sea

    Energy Technology Data Exchange (ETDEWEB)

    Hammingh, P.; Geilenkirchen, G. [Netherlands Environmental Assessment Agency PBL, Bilthoven (Netherlands); Maas, R. [National Institute of Public Health and Environmental Protection RIVM, Bilthoven (Netherlands); Holland, M.R. [Ecometrics Research and Consulting EMRC, Reading (United Kingdom); Jonson, J.E. [The Meteorological Synthesizing Centre - West MSC-W, Norwegian Meteorological Institute, Oslo (Norway)

    2012-06-15

    In the last five to ten years, concerns about the health and ecosystem effects of air polluting emissions from ships have grown in international policy debate regarding further air pollutant emissions control. As an outcome of the debate, the International Maritime Organisation (IMO) adopted more stringent emission standards in 2008 to further control air pollution from sea shipping. For example, their most stringent nitrogen oxide emission standards are about 75 per cent lower than the standards for current ships. However, these most stringent standards are only mandatory in specific emission control areas designated by the IMO. Such specific areas aim to protect densely populated areas and sensitive ecosystems from air pollution from nearby international shipping. Prior to a possible application for designation of a nitrogen oxide emission control area, the eight North Sea countries commissioned an assessment of the environmental impacts and health benefits (this report) and the economic impacts and costs (Danish EPA, 2012). The main conclusions of this assessment are presented and concisely explained below. A detailed elaboration of the work carried out, the results and the uncertainties can be found in 'Full results'.

  1. Nitrogen removal and nitrous oxide emission in surface flow constructed wetlands for treating sewage treatment plant effluent: Effect of C/N ratios.

    Science.gov (United States)

    Li, Ming; Wu, Haiming; Zhang, Jian; Ngo, Huu Hao; Guo, Wenshan; Kong, Qiang

    2017-09-01

    In order to design treatment wetlands with maximal nitrogen removal and minimal nitrous oxide (N 2 O) emission, the effect of influent C/N ratios on nitrogen removal and N 2 O emission in surface flow constructed wetlands (SF CWs) for sewage treatment plant effluent treatment was investigated in this study. The results showed that nitrogen removal and N 2 O emission in CWs were significantly affected by C/N ratio of influent. Much higher removal efficiency of NH 4 + -N (98%) and TN (90%) was obtained simultaneously in SF CWs at C/N ratios of 12:1, and low N 2 O emission (8.2mg/m 2 /d) and the percentage of N 2 O-N emission in TN removal (1.44%) were also observed. These results obtained in this study would be utilized to determine how N 2 O fluxes respond to variations in C/N ratios and to improve the sustainability of CWs for wastewater treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Laser-induced fluorescence for medical diagnostics

    International Nuclear Information System (INIS)

    Andersson Engels, S.

    1989-12-01

    Laser-induced fluorescence as a tool for tissue diagnostics is discussed. Both spectrally and time-resolved fluorescence signals are studied to optimize the demarcation of diseased lesions from normal tissue. The presentation is focused on two fields of application: the identification of malignant tumours and atherosclerotic plaques. Tissue autofluorescence as well as fluorescence from administered drugs have been utilized in diseased tissue diagnosis. The fluorescence criterion for tissue diagnosis is, as far as possible, chosen to be independent of unknown fluorescence parameters, which are not correlated to the type of tissue investigated. Both a dependence on biological parameters, such as light absorption in blood, and instrumental characteristics, such as excitation pulse fluctuations and detection geometry, can be minimized. Several chemical compounds have been studied in animal experiments after intraveneous injection to verify their capacity as malignant tumour marking drugs under laser excitation and fluorescence detection. Another objective of these studies was to improve our understanding of the mechanism and chemistry behind the retention of the various drugs in tissue. The properties of a chemical which maximize its selective retention in tumours are discussed. In order to utilize this diagnostic modality, three different clinically adapted sets of instrumentation have been developed and are presented. Two of the systems are nitrogen-laser-based fluorosensors; one is a point-monitoring system with full spectral resolution and the other one is an imaging system with up to four simultaneously recorded images in different spectral bands. The third system is a low-cost point-monitoring mercury-lamp-based fluoroscence emission as well as reflection characteristics of tissue. (author)

  3. Fluorescence Intrinsic Characterization of Excitation-Emission Matrix Using Multi-Dimensional Ensemble Empirical Mode Decomposition

    Directory of Open Access Journals (Sweden)

    Tzu-Chien Hsiao

    2013-11-01

    Full Text Available Excitation-emission matrix (EEM fluorescence spectroscopy is a noninvasive method for tissue diagnosis and has become important in clinical use. However, the intrinsic characterization of EEM fluorescence remains unclear. Photobleaching and the complexity of the chemical compounds make it difficult to distinguish individual compounds due to overlapping features. Conventional studies use principal component analysis (PCA for EEM fluorescence analysis, and the relationship between the EEM features extracted by PCA and diseases has been examined. The spectral features of different tissue constituents are not fully separable or clearly defined. Recently, a non-stationary method called multi-dimensional ensemble empirical mode decomposition (MEEMD was introduced; this method can extract the intrinsic oscillations on multiple spatial scales without loss of information. The aim of this study was to propose a fluorescence spectroscopy system for EEM measurements and to describe a method for extracting the intrinsic characteristics of EEM by MEEMD. The results indicate that, although PCA provides the principal factor for the spectral features associated with chemical compounds, MEEMD can provide additional intrinsic features with more reliable mapping of the chemical compounds. MEEMD has the potential to extract intrinsic fluorescence features and improve the detection of biochemical changes.

  4. Biomolecule-to-fluorescent-color encoder: modulation of fluorescence emission via DNA structural changes

    Science.gov (United States)

    Nishimura, Takahiro; Ogura, Yusuke; Yamada, Kenji; Ohno, Yuko; Tanida, Jun

    2014-01-01

    A biomolecule-to-fluorescent-color (B/F) encoder for optical readout of biomolecular information is proposed. In the B/F encoder, a set of fluorescence wavelengths and their intensity levels are used for coding of a biomolecular signal. A hybridization chain reaction of hairpin DNAs labeled with fluorescent reporters was performed to generate the fluorescence color codes. The fluorescence is modulated via fluorescence resonance energy transfer, which is controlled by DNA structural changes. The results demonstrate that fluorescent color codes can be configured based on two wavelengths and five intensities using the B/F encoder, and the assigned codes can be retrieved via fluorescence measurements. PMID:25071950

  5. State-of-the art comparability of corrected emission spectra. 2. Field laboratory assessment of calibration performance using spectral fluorescence standards.

    Science.gov (United States)

    Resch-Genger, Ute; Bremser, Wolfram; Pfeifer, Dietmar; Spieles, Monika; Hoffmann, Angelika; DeRose, Paul C; Zwinkels, Joanne C; Gauthier, François; Ebert, Bernd; Taubert, R Dieter; Voigt, Jan; Hollandt, Jörg; Macdonald, Rainer

    2012-05-01

    In the second part of this two-part series on the state-of-the-art comparability of corrected emission spectra, we have extended this assessment to the broader community of fluorescence spectroscopists by involving 12 field laboratories that were randomly selected on the basis of their fluorescence measuring equipment. These laboratories performed a reference material (RM)-based fluorometer calibration with commercially available spectral fluorescence standards following a standard operating procedure that involved routine measurement conditions and the data evaluation software LINKCORR developed and provided by the Federal Institute for Materials Research and Testing (BAM). This instrument-specific emission correction curve was subsequently used for the determination of the corrected emission spectra of three test dyes, X, QS, and Y, revealing an average accuracy of 6.8% for the corrected emission spectra. This compares well with the relative standard uncertainties of 4.2% for physical standard-based spectral corrections demonstrated in the first part of this study (previous paper in this issue) involving an international group of four expert laboratories. The excellent comparability of the measurements of the field laboratories also demonstrates the effectiveness of RM-based correction procedures.

  6. X-ray fluorescence analysis and optical emission spectrometry of an roman mirror from Tomis, Romania

    International Nuclear Information System (INIS)

    Belc, M.; Bogoi, M.; Ionescu, D.; Guita, D.; Caiteanu, S.; Caiteanu, D.

    2000-01-01

    The miscellaneous population of Roman Empire, their diverse cultural tradition, their ability to assimilate the roman civilization spirits, had determined a permanent reassessment superimposed upon the roman contribution. Analysis was undertaken using optical emission spectrometry and non-destructive X-ray fluorescence. X-ray fluorescence analysis is a well-established method and is often used in archaeometry and other work dealing with valuable objects pertaining to the history of art and civilization. Roman mirror analysed has been found not to be made of speculum (a high tin bronze). (authors)

  7. Detection of vegetation stress from laser-induced fluorescence signatures

    International Nuclear Information System (INIS)

    Subhash, N.

    1995-01-01

    The in vivo laser-induced fluorescence (LIF) signatures of UV irradiated Salvia splendens plants were measured using an Optical Multichannel Analyser (OMA) system with Nitrogen laser excitation. The LIF spectra which consisted of the blue-green and the red chlorophyll bands were analysed with a non-linear interactive procedure using Gaussian spectral functions. The fluorescence intensity ratios of the various bands obtained from curve fitted parameters were found to be more sensitive to changes in the photosynthetic activity of the plant. The variation in the intensity ratio for the chlorophyll bands for nutrient stressed sunflower, cotton and groundnut plants as well as the nutrient and water stressed rice plants are also presented. It is observed that vegetation stress not only changes the fluorescence intensity ratios and the vitality index of the plant but also changes the peak position of the emission bands, in some cases. It is also seen that analysis of the fluorescence spectra in vegetation remote sensing applications would require a deconvolution procedure to evaluate the exact contribution of each band in the total spectra. (author). 23 refs, 8 figs, 5 tabs

  8. Synthesis and bioimaging of biodegradable red fluorescent organic nanoparticles with aggregation-induced emission characteristics.

    Science.gov (United States)

    Xu, Dazhuang; Zou, Hui; Liu, Meiying; Tian, Jianwen; Huang, Hongye; Wan, Qing; Dai, Yanfeng; Wen, Yuanqing; Zhang, Xiaoyong; Wei, Yen

    2017-12-15

    Fluorescent organic nanoparticles (FONs) with aggregation-induced emission (AIE) features have recently emerged as promising fluorescent probes for biomedical applications owing to their excellent optical properties, designability and biocompatibility. Significant progress has been made recently for synthesis and biomedical applications of these AIE-active FONs. However, only very limited reports have demonstrated the fabrication of biodegradable AIE-active FONs with red fluorescence emission. In this study, a novel strategy has been developed for the preparation of biodegradable AIE-active polyurethanes (PUs) through a two-step polymerization, in which the diisocyanate-terminated polyethylene glycol (NCO-PEG-NCO) was synthesized and subsequently conjugated with diamine-containing AIE dye (NH 2 -Phe-NH 2 ). The successful synthesis of AIE-active Phe-PEG 2000 PUs is evidenced by a series of characterization techniques. Because of the formation of AIE-active amphiphilic PUs, the final copolymers can self-assemble into spherical nanoparticles, which exhibit strong luminescence and high water dispersion. The biological evaluation results suggest that the AIE-active Phe-PEG 2000 FONs possess low toxicity and desirable cell permeability. Therefore, we anticipate that these AIE-active FONs with biodegradable potential will trigger much research enthusiasm and effort toward the creation of new AIE-active materials with improved properties for various biomedical applications. Copyright © 2017 Elsevier Inc. All rights reserved.

  9. Spatially explicit fate factors of waterborne nitrogen emissions at the global scale

    DEFF Research Database (Denmark)

    Cosme, Nuno Miguel Dias; Mayorga, Emilio; Hauschild, Michael Zwicky

    2017-01-01

    water. Spatial aggregation of the FFs at the continental level decreases this variation to 1 order of magnitude or less for all routes. Coastal water residence time was found to show inconsistency and scarcity of literature sources. Improvement of data quality for this parameter is suggested......Purpose: Marine eutrophication impacts due to waterborne nitrogen (N) emissions may vary significantly with their type and location. The environmental fate of dissolved inorganic nitrogen (DIN) forms is essential to understand the impacts they may trigger in receiving coastal waters. Current life...... and river basin resolution. Methods: The FF modelling work includes DIN removal processes in both inland (soil and river) and marine compartments. Model input parameters are the removal coefficients extracted from the Global NEWS 2-DIN model and residence time of receiving coastal waters. The resulting FFs...

  10. Fluorescence and amplified spontaneous emission of glass forming compounds containing styryl-4H-pyran-4-ylidene fragment

    Energy Technology Data Exchange (ETDEWEB)

    Vembris, Aivars, E-mail: aivars.vembris@cfi.lu.lv [Institute of Solid State Physics, University of Latvia, 8 Kengaraga Street, Riga LV-1063 (Latvia); Muzikante, Inta [Institute of Solid State Physics, University of Latvia, 8 Kengaraga Street, Riga LV-1063 (Latvia); Karpicz, Renata; Sliauzys, Gytis [Institute of Physics, Center for Physical Sciences and Technology, A. Gostauto 11, LT-01108 Vilnius (Lithuania); Miasojedovas, Arunas; Jursenas, Saulius [Institute of Applied Research, Vilnius University, Sauletekio 9-III, LT-10222 Vilnius (Lithuania); Gulbinas, Vidmantas [Institute of Physics, Center for Physical Sciences and Technology, A. Gostauto 11, LT-01108 Vilnius (Lithuania)

    2012-09-15

    Potential of glassy films of newly synthesised low molecular weight organic molecules for light amplification and lasing applications has been investigated by analysing fluorescence, transient differential absorption and amplified spontaneous emission properties. These non-symmetric and symmetric molecules contain styryl-4H-pyran-4-ylidene fragment with three different electron acceptor groups: dicyanomethylene, barbituric acid, indene-1,3-dione. Fluorescence quantum yields of the investigated compounds in solutions are between 0.32 and 0.54, while they drop down by an order of magnitude in thin solid films. Incorporation of bulky side groups reduced excitonic interactions enabling manifestation of amplified spontaneous emission in the neat films of the investigated derivatives. - Highlights: Black-Right-Pointing-Pointer Bulky substituents attached to DCM dye enable formation of neat glassy films. Black-Right-Pointing-Pointer Investigated dyes show amplified spontaneous emission in neat films. Black-Right-Pointing-Pointer Two electron donor groups negatively influence light amplification.

  11. An expression for the atomic fluorescence and thermal-emission intensity under conditions of near saturation and arbitrary self-absorption

    NARCIS (Netherlands)

    Omenetto, N.; Winefordner, J.D.; Alkemade, C.T.J.

    An expression for the effect of self-absorption on the fluorescence and thermal emission intensities is derived by taking into account stimulated emission. A simple, idealized case is considered, consisting of a two level atomic system, in a flame, homogeneous with respect to temperature and

  12. Sulfur and nitrogen co-doped carbon dots sensors for nitric oxide fluorescence quantification

    Energy Technology Data Exchange (ETDEWEB)

    Simões, Eliana F.C. [Centro de Investigação em Química da Universidade do Porto (CIQ-UP), Faculdade de Farmácia da Universidade de Coimbra, Pólo das Ciências da Saúde, 3000-548 Coimbra (Portugal); Centro de Investigação em Química da Universidade do Porto (CIQ-UP), Departamento de Geociências, Ambiente e Ordenamento do Território, Faculdade de Ciências da Universidade do Porto, R. Campo Alegre 687, 4169-007 Porto (Portugal); Leitão, João M.M., E-mail: jleitao@ff.uc.pt [Centro de Investigação em Química da Universidade do Porto (CIQ-UP), Faculdade de Farmácia da Universidade de Coimbra, Pólo das Ciências da Saúde, 3000-548 Coimbra (Portugal); Esteves da Silva, Joaquim C.G. [Centro de Investigação em Química da Universidade do Porto (CIQ-UP), Departamento de Geociências, Ambiente e Ordenamento do Território, Faculdade de Ciências da Universidade do Porto, R. Campo Alegre 687, 4169-007 Porto (Portugal)

    2017-04-01

    Microwave synthetized sulfur and nitrogen co-doped carbon dots responded selectively to nitric oxide (NO) at pH 7. Citric acid, urea and sodium thiosulfate in the proportion of 1:1:3 were used respectively as carbon, nitrogen and sulfur sources in the carbon dots microwave synthesis. For this synthesis, the three compounds were diluted in 15 mL of water and exposed for 5 min to a microwave radiation of 700 W. It is observed that the main factor contributing to the increased sensitivity and selectivity response to NO at pH 7 is the sodium thiosulfate used as sulfur source. A linear response range from 1 to 25 μM with a sensitivity of 16 μM{sup −1} and a detection limit of 0.3 μM were obtained. The NO quantification capability was assessed in standard and in fortified serum solutions. - Highlights: • S,N co-doped CDs were microwave synthetized from citric acid, urea and sodium thiosulfate. • The NO fluorescence sensing was evaluated at pH 7. • The selective and sensitive detection of NO at pH 7 was achieved. • Good NO quantification results in serum samples were obtained.

  13. Sulfur and nitrogen co-doped carbon dots sensors for nitric oxide fluorescence quantification

    International Nuclear Information System (INIS)

    Simões, Eliana F.C.; Leitão, João M.M.; Esteves da Silva, Joaquim C.G.

    2017-01-01

    Microwave synthetized sulfur and nitrogen co-doped carbon dots responded selectively to nitric oxide (NO) at pH 7. Citric acid, urea and sodium thiosulfate in the proportion of 1:1:3 were used respectively as carbon, nitrogen and sulfur sources in the carbon dots microwave synthesis. For this synthesis, the three compounds were diluted in 15 mL of water and exposed for 5 min to a microwave radiation of 700 W. It is observed that the main factor contributing to the increased sensitivity and selectivity response to NO at pH 7 is the sodium thiosulfate used as sulfur source. A linear response range from 1 to 25 μM with a sensitivity of 16 μM"−"1 and a detection limit of 0.3 μM were obtained. The NO quantification capability was assessed in standard and in fortified serum solutions. - Highlights: • S,N co-doped CDs were microwave synthetized from citric acid, urea and sodium thiosulfate. • The NO fluorescence sensing was evaluated at pH 7. • The selective and sensitive detection of NO at pH 7 was achieved. • Good NO quantification results in serum samples were obtained.

  14. Nitrogen-doped graphene quantum dots-based fluorescence molecularly imprinted sensor for thiacloprid detection.

    Science.gov (United States)

    Liu, Yang; Cao, Nan; Gui, Wenying; Ma, Qiang

    2018-06-01

    In this paper, a test strip-based sensor was developed for thiacloprid quantitative detection based on PDA molecularly imprinted polymer (MIP) and nitrogen-doped graphene quantum dots (N-GQDs). Thiacloprid is a new type of nicotine insecticide, which can block the normal neurotransmitter delivery process in insects. In the sensing system, N-GQDs were immersed into filter paper at first. Then, dopamine (DA) with thiacloprid can be self-polymerized on test strip surface to form the uniform PDA film. After removed thiacloprid template, the established poly dopamine (PDA) MIP can selectively recognize thiacloprid. As a result, captured thiacloprid can enhance the fluorescence intensity of N-GQDs into the test strip. As a result, the fluorescence intensity of N-GQDs can be linearly related within a certain range of thiacloprid concentration. Under the optimum conditions, the proposed sensor for thiacloprid detection exhibited a linear ranging from 0.1 mg/L to 10 mg/L with a low detection limit of 0.03 mg/L. The N-GQDs based test strip-based sensor for thiaclopridis reported for the first time. The sensing system has high selectivity to thiacloprid and provides new opportunities in the pesticide detection. Copyright © 2018 Elsevier B.V. All rights reserved.

  15. Excitation of surface plasmon polariton modes with multiple nitrogen vacancy centers in single nanodiamonds

    International Nuclear Information System (INIS)

    Kumar, Shailesh; Lausen, Jens L; Andersen, Sebastian K H; Roberts, Alexander S; Radko, Ilya P; Bozhevolnyi, Sergey I; Garcia-Ortiz, Cesar E; Smith, Cameron L C; Kristensen, Anders

    2016-01-01

    Nitrogen-vacancy (NV) centers in diamonds are interesting due to their remarkable characteristics that are well suited to applications in quantum-information processing and magnetic field sensing, as well as representing stable fluorescent sources. Multiple NV centers in nanodiamonds (NDs) are especially useful as biological fluorophores due to their chemical neutrality, brightness and room-temperature photostability. Furthermore, NDs containing multiple NV centers also have potential in high-precision magnetic field and temperature sensing. Coupling NV centers to propagating surface plasmon polariton (SPP) modes gives a base for lab-on-a-chip sensing devices, allows enhanced fluorescence emission and collection which can further enhance the precision of NV-based sensors. Here, we investigate coupling of multiple NV centers in individual NDs to the SPP modes supported by silver surfaces protected by thin dielectric layers and by gold V-grooves (VGs) produced via the self-terminated silicon etching. In the first case, we concentrate on monitoring differences in fluorescence spectra obtained from a source ND, which is illuminated by a pump laser, and from a scattering ND illuminated only by the fluorescence-excited SPP radiation. In the second case, we observe changes in the average NV lifetime when the same ND is characterized outside and inside a VG. Fluorescence emission from the VG terminations is also observed, which confirms the NV coupling to the VG-supported SPP modes. (paper)

  16. Excitation of surface plasmon polariton modes with multiple nitrogen vacancy centers in single nanodiamonds

    Science.gov (United States)

    Kumar, Shailesh; Lausen, Jens L.; Garcia-Ortiz, Cesar E.; Andersen, Sebastian K. H.; Roberts, Alexander S.; Radko, Ilya P.; Smith, Cameron L. C.; Kristensen, Anders; Bozhevolnyi, Sergey I.

    2016-02-01

    Nitrogen-vacancy (NV) centers in diamonds are interesting due to their remarkable characteristics that are well suited to applications in quantum-information processing and magnetic field sensing, as well as representing stable fluorescent sources. Multiple NV centers in nanodiamonds (NDs) are especially useful as biological fluorophores due to their chemical neutrality, brightness and room-temperature photostability. Furthermore, NDs containing multiple NV centers also have potential in high-precision magnetic field and temperature sensing. Coupling NV centers to propagating surface plasmon polariton (SPP) modes gives a base for lab-on-a-chip sensing devices, allows enhanced fluorescence emission and collection which can further enhance the precision of NV-based sensors. Here, we investigate coupling of multiple NV centers in individual NDs to the SPP modes supported by silver surfaces protected by thin dielectric layers and by gold V-grooves (VGs) produced via the self-terminated silicon etching. In the first case, we concentrate on monitoring differences in fluorescence spectra obtained from a source ND, which is illuminated by a pump laser, and from a scattering ND illuminated only by the fluorescence-excited SPP radiation. In the second case, we observe changes in the average NV lifetime when the same ND is characterized outside and inside a VG. Fluorescence emission from the VG terminations is also observed, which confirms the NV coupling to the VG-supported SPP modes.

  17. Fluorescence properties of the anti-tumour alkaloid luotonin A and new synthetic analogues: pH modulation as an approach to their fluorimetric quantitation in biological samples

    International Nuclear Information System (INIS)

    González-Ruiz, Víctor; González-Cuevas, Yamisley; Arunachalam, Sankaralingam; Martín, M. Antonia; Olives, Ana I.; Ribelles, Pascual; Ramos, M. Teresa; Menéndez, J. Carlos

    2012-01-01

    Luotonin A is an alkaloid structurally related to the natural anti-tumour agent camptothecin. The fluorescence behaviour of luotonin A and a series of six analogues is described in the present work. The influence of solvent polarity and pH on the native fluorescence properties of these alkaloids was studied, finding that in organic solvents or in aqueous solutions (pH 5.5–7.2) the neutral form of the luotonin derivatives emit in the region of 410–450 nm but, in both media, acidification to pH values below 3.0 causes a new emission band to appear at about 500 nm. An ESPT reaction occurs due to the protonation of the basic nitrogen atoms of the pentacyclic ring. Acid-base titrations of luotonin A and its derivatives in aqueous and acetonitrile media were carried out in order to determine their pK a ⁎ values which were around 2, showing these compounds to be very weak bases. In aqueous media, the absence of an iso-emissive point in the emission spectra suggests the existence of more than two species in the proton transfer equilibria. The basicity of the luotonin A derivatives is increased in organic media, and a good correlation between the pK a ⁎ values and the chemical structure was found. The protonation of luotonin A was also studied by 1 H-NMR and 13 C-NMR experiments, which proved the protonation of the nitrogen atoms at the positions 5 and 6 of the pentacyclic ring. The fluorescence quantum yields were determined in ethanol and in aqueous solutions under neutral and acidic conditions. The fluorescence quantum yields were higher in water for the case of the more polar compounds, and the opposite result was obtained for the more hydrophobic ones. The remarkable and interesting fluorescence properties of luotonin A prompted the development of its fluorimetric analytical quantitation, obtaining very good analytical features. - Highlights: ► This is the first study on the fluorescence properties of luotonin A analogues. ► Fluorescence and NMR experiments

  18. Fluorescent derivatives of nucleotides. Metal ion interactions and pH dependency.

    Science.gov (United States)

    Vanderkooi, J M; Weiss, C J; Woodrow, G V

    1979-02-01

    The fluorescence parameters of ethenoadenosine derivatives are influenced by metal cations and pH, as summarized here. The pH profile of ethenoadenosine determined by fluorescence intensity gives a normal titration curve and is not affected by ionic strength. In contrast, the pH titration curves of etheno-ATP, etheno ADP, and etheno AMP depend upon ionic strength. At high ionic strength normal curves are obtained, whereas at low ionic strength anomalies are obtained; this suggests that the phosphates can interact with the ring, possibly by hydrogen binding to the ring nitrogens. The room temperature fluorescence of ethenoadenosine occurs from the base form, although excitation of either the acid or base forms can contribute to the emission. This result can be explained if the excited state pK is lower than the ground state pK, and if deprotonation occurs within the time scale of the excited state. At low pH values the fluorescence lifetime of the base form is dependent upon the buffer concentration, indicating that the reverse reaction, protonation, occurs. The affinity constants for the binding of metals to the ethenoadenosine phosphates resemble those for the corresponding adenosine phosphates. Ni(II) and Co(II) are more effective than Mn(II) in quenching the fluorescence of ethenoadenosine phosphates; this result is predicted by Förster's theory for energy transfer based upon the overlap between donor emission spectrum and acceptor absorption spectrum. The diamagnetic ions Mg(II), Ca(II), and Zn(II) do not appear to affect the fluorescence of the ethenoadenosine phosphates directly, but rather to affect the conformation of the molecule, thereby affecting the quantum yield.

  19. Nitrous oxide emissions from a peatbog after 13 years of experimental nitrogen deposition

    Directory of Open Access Journals (Sweden)

    S. R. Leeson

    2017-12-01

    Full Text Available Nitrogen deposition was experimentally increased on a Scottish peatbog over a period of 13 years (2002–2015. Nitrogen was applied in three forms, NH3 gas, NH4Cl solution, and NaNO3 solution, at rates ranging from 8 (ambient to 64 kg N ha−1 yr−1, and higher near the NH3 fumigation source. An automated system was used to apply the nitrogen, such that the deposition was realistic in terms of rates and high frequency of deposition events. We measured the response of nitrous oxide (N2O flux to the increased nitrogen input. Prior expectations, based on the IPCC default emission factor, were that 1 % of the added nitrogen would be emitted as N2O. In the plots treated with NH4+ and NO3− solution, no response was seen, and there was a tendency for N2O fluxes to be reduced by additional nitrogen, though this was not significant. Areas subjected to high NH3 emitted more N2O than expected, up to 8.5 % of the added nitrogen. Differences in the response are related to the impact of the nitrogen treatments on the vegetation. In the NH4+ and NO3− treatments, all the additional nitrogen is effectively immobilised in the vegetation and top 10 cm of peat. In the NH3 treatment, much of the vegetation was killed off by high doses of NH3, and the nitrogen was presumably more available to denitrifying bacteria. The design of the wet and dry experimental treatments meant that they differed in statistical power, and we are less likely to detect an effect of the NH4+ and NO3− treatments, though they avoid issues of pseudo-replication.

  20. Signatures of hot electrons and fluorescence in Mo Kα emission on Z

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, S. B.; Ampleford, D. J.; Cuneo, M. E.; Jones, B.; Jennings, C. A.; Coverdale, C. A.; Rochau, G. A.; Dunham, G. [Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States); Ouart, N.; Dasgupta, A.; Giuliani, J. L. [Naval Research Laboratory, Washington, DC 20375 (United States); Apruzese, J. P. [Consultant to NRL through Engility Corp., Chantilly, Virginia 20151 (United States)

    2014-03-15

    Recent experiments on the Z accelerator have produced high-energy (17 keV) inner-shell K-alpha emission from molybdenum wire array z-pinches. Extensive absolute power and spectroscopic diagnostics along with collisional-radiative modeling enable detailed investigation into the roles of thermal, hot electron, and fluorescence processes in the production of high-energy x-rays. We show that changing the dimensions of the arrays can impact the proportion of thermal and non-thermal K-shell x-rays.

  1. Mechanistic modeling of reactive soil nitrogen emissions across agricultural management practices

    Science.gov (United States)

    Rasool, Q. Z.; Miller, D. J.; Bash, J. O.; Venterea, R. T.; Cooter, E. J.; Hastings, M. G.; Cohan, D. S.

    2017-12-01

    The global reactive nitrogen (N) budget has increased by a factor of 2-3 from pre-industrial levels. This increase is especially pronounced in highly N fertilized agricultural regions in summer. The reactive N emissions from soil to atmosphere can be in reduced (NH3) or oxidized (NO, HONO, N2O) forms, depending on complex biogeochemical transformations of soil N reservoirs. Air quality models like CMAQ typically neglect soil emissions of HONO and N2O. Previously, soil NO emissions estimated by models like CMAQ remained parametric and inconsistent with soil NH3 emissions. Thus, there is a need to more mechanistically and consistently represent the soil N processes that lead to reactive N emissions to the atmosphere. Our updated approach estimates soil NO, HONO and N2O emissions by incorporating detailed agricultural fertilizer inputs from EPIC, and CMAQ-modeled N deposition, into the soil N pool. EPIC addresses the nitrification, denitrification and volatilization rates along with soil N pools for agricultural soils. Suitable updates to account for factors like nitrite (NO2-) accumulation not addressed in EPIC, will also be made. The NO and N2O emissions from nitrification and denitrification are computed mechanistically using the N sub-model of DAYCENT. These mechanistic definitions use soil water content, temperature, NH4+ and NO3- concentrations, gas diffusivity and labile C availability as dependent parameters at various soil layers. Soil HONO emissions found to be most probable under high NO2- availability will be based on observed ratios of HONO to NO emissions under different soil moistures, pH and soil types. The updated scheme will utilize field-specific soil properties and N inputs across differing manure management practices such as tillage. Comparison of the modeled soil NO emission rates from the new mechanistic and existing schemes against field measurements will be discussed. Our updated framework will help to predict the diurnal and daily variability

  2. A tumor-targeted polymer theranostics platform for positron emission tomography and fluorescence imaging

    Czech Academy of Sciences Publication Activity Database

    Koziolová, Eva; Goel, S.; Chytil, Petr; Janoušková, Olga; Barnhart, T. E.; Cai, W.; Etrych, Tomáš

    2017-01-01

    Roč. 9, č. 30 (2017), s. 10906-10918 ISSN 2040-3364 R&D Projects: GA ČR(CZ) GA15-02986S; GA MZd(CZ) NV16-28594A; GA MŠk(CZ) LO1507 Institutional support: RVO:61389013 Keywords : N-(2-hydroxypropyl)methacrylamide (HPMA) copolymers * positron emission tomography ( PET ) * fluorescence imaging Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer science Impact factor: 7.367, year: 2016

  3. Analysis of Spectral Features of Seawaterbiooptical Components Fluorescence from the Excitation-emission Matrix

    Science.gov (United States)

    Salyuk, P. A.; Nagorny, I. G.

    The paper presents the method for processing of excitation-emission matrix of sea water and the allocation of the spectral characteristics of different types of colored dissolved organic matter (CDOM) and phytoplankton cells in seawater. The method consists of identification of regularly observed fluorescence peaks of CDOM in marine waters of different type and definition of the spectral ranges, where the predominant influence of these peaks are observed.

  4. Relating N2O emissions during biological nitrogen removal with operating conditions using multivariate statistical techniques.

    Science.gov (United States)

    Vasilaki, V; Volcke, E I P; Nandi, A K; van Loosdrecht, M C M; Katsou, E

    2018-04-26

    Multivariate statistical analysis was applied to investigate the dependencies and underlying patterns between N 2 O emissions and online operational variables (dissolved oxygen and nitrogen component concentrations, temperature and influent flow-rate) during biological nitrogen removal from wastewater. The system under study was a full-scale reactor, for which hourly sensor data were available. The 15-month long monitoring campaign was divided into 10 sub-periods based on the profile of N 2 O emissions, using Binary Segmentation. The dependencies between operating variables and N 2 O emissions fluctuated according to Spearman's rank correlation. The correlation between N 2 O emissions and nitrite concentrations ranged between 0.51 and 0.78. Correlation >0.7 between N 2 O emissions and nitrate concentrations was observed at sub-periods with average temperature lower than 12 °C. Hierarchical k-means clustering and principal component analysis linked N 2 O emission peaks with precipitation events and ammonium concentrations higher than 2 mg/L, especially in sub-periods characterized by low N 2 O fluxes. Additionally, the highest ranges of measured N 2 O fluxes belonged to clusters corresponding with NO 3 -N concentration less than 1 mg/L in the upstream plug-flow reactor (middle of oxic zone), indicating slow nitrification rates. The results showed that the range of N 2 O emissions partially depends on the prior behavior of the system. The principal component analysis validated the findings from the clustering analysis and showed that ammonium, nitrate, nitrite and temperature explained a considerable percentage of the variance in the system for the majority of the sub-periods. The applied statistical methods, linked the different ranges of emissions with the system variables, provided insights on the effect of operating conditions on N 2 O emissions in each sub-period and can be integrated into N 2 O emissions data processing at wastewater treatment plants

  5. Vermicomposting as a technology for reducing nitrogen losses and greenhouse gas emissions from small-scale composting

    NARCIS (Netherlands)

    Nigussie, Abebe; Kuijper, Thomas; Bruun, Sander; Neergaard, de Andreas

    2016-01-01

    Thermophilic composting produces a significant amount of greenhouse gases. The objectives of this study were (i) to evaluate the effectiveness of vermicomposting to reduce nitrogen losses and greenhouse gases emissions compared to thermophilic composting, and (ii) to determine the effect of

  6. Creation of high density ensembles of nitrogen-vacancy centers in nitrogen-rich type Ib nanodiamonds

    International Nuclear Information System (INIS)

    Su, Long-Jyun; Fang, Chia-Yi; Chang, Yu-Tang; Chang, Huan-Cheng; Chen, Kuan-Ming; Yu, Yueh-Chung; Hsu, Jui-Hung

    2013-01-01

    This work explores the possibility of increasing the density of negatively charged nitrogen-vacancy centers ([NV − ]) in nanodiamonds using nitrogen-rich type Ib diamond powders as the starting material. The nanodiamonds (10–100 nm in diameter) were prepared by ball milling of microdiamonds, in which the density of neutral and atomically dispersed nitrogen atoms ([N 0 ]) was measured by diffuse reflectance infrared Fourier transform spectroscopy. A systematic measurement of the fluorescence intensities and lifetimes of the crushed monocrystalline diamonds as a function of [N 0 ] indicated that [NV − ] increases nearly linearly with [N 0 ] at 100–200 ppm. The trend, however, failed to continue for nanodiamonds with higher [N 0 ] (up to 390 ppm) but poorer crystallinity. We attribute the result to a combined effect of fluorescence quenching as well as the lower conversion efficiency of vacancies to NV − due to the presence of more impurities and defects in these as-grown diamond crystallites. The principles and practice of fabricating brighter and smaller fluorescent nanodiamonds are discussed. (paper)

  7. Creation of high density ensembles of nitrogen-vacancy centers in nitrogen-rich type Ib nanodiamonds.

    Science.gov (United States)

    Su, Long-Jyun; Fang, Chia-Yi; Chang, Yu-Tang; Chen, Kuan-Ming; Yu, Yueh-Chung; Hsu, Jui-Hung; Chang, Huan-Cheng

    2013-08-09

    This work explores the possibility of increasing the density of negatively charged nitrogen-vacancy centers ([NV(-)]) in nanodiamonds using nitrogen-rich type Ib diamond powders as the starting material. The nanodiamonds (10-100 nm in diameter) were prepared by ball milling of microdiamonds, in which the density of neutral and atomically dispersed nitrogen atoms ([N(0)]) was measured by diffuse reflectance infrared Fourier transform spectroscopy. A systematic measurement of the fluorescence intensities and lifetimes of the crushed monocrystalline diamonds as a function of [N(0)] indicated that [NV(-)] increases nearly linearly with [N(0)] at 100-200 ppm. The trend, however, failed to continue for nanodiamonds with higher [N(0)] (up to 390 ppm) but poorer crystallinity. We attribute the result to a combined effect of fluorescence quenching as well as the lower conversion efficiency of vacancies to NV(-) due to the presence of more impurities and defects in these as-grown diamond crystallites. The principles and practice of fabricating brighter and smaller fluorescent nanodiamonds are discussed.

  8. White organic light emitting devices with hybrid emissive layers combining phosphorescence and fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Lei Gangtie; Chen Xiaolan; Wang Lei; Zhu Meixiang; Zhu Weiguo [Key Lab of Environmental-friendly Chemistry and Application of Ministry of Education, College of Chemistry, Xiangtan University, Xiangtan 411105 (China); Wang Liduo; Qiu Yong [Key Lab of Organic-Optoelectronics and Molecular Sciences of Ministry of Education, Department of Chemistry, Tsinghua University, Beijing 100084 (China)], E-mail: lgt@xtu.edu.cn

    2008-05-21

    We fabricated a white organic light-emitting diode (WOLED) by hybrid emissive layers which combined phosphorescence with fluorescence. In this device, the thin layer of 4-(dicyanomethylene)-2-(t-butyl)-6-(1, 1, 7, 7-tetramethyljulolidyl-9-enyl)-4H-pyran played the role of undoped red emissive layer which was inserted between two blue phosphorescence emissive layers. The blue phosphorescent dye was bis[(4, 6-difluorophenyl)-pyridinato-N, C{sup 2}] (picolinato) Ir(III), which was doped in the host material, N, N'-dicarbazolyl-1, 4-dimethene-benzene. The WOLED showed stable Commission Internationale de L'Eclairage coordinates and a high efficency of 9.6 cd A{sup -1} when the current density was 1.8 A m{sup -2}. The maximum luminance of the device achieved was 17 400 cd m{sup -2} when the current density was 3000 A m{sup -2}.

  9. Characteristics of mercury emission from linear type of spent fluorescent lamp.

    Science.gov (United States)

    Rhee, Seung-Whee; Choi, Hyo-Hyun; Park, Hun-Su

    2014-06-01

    In order to recycle the linear type of SFL (spent fluorescent lamp), mercury from SFL should be controlled to prevent leaking into the environment. For mercury emission from SFL, mercury concentration is estimated in the parts of SFL such as glass tube, phosphor powder, and base cap using the end-cutting unit. It is also evaluated mercury emission in the effluent gas in the end-cutting unit with changing flow rate. From the results of mercury emission from SFLs, phosphor powder has greater than 80% of mercury amount in SFL and about 15% of mercury amount contained in glass tube. The initial mercury concentration in vapor phase is almost decreased linearly with increasing airflow rate from 0.7 L/min to 1.3 L/min. It is desirable that airflow rate should be high until the concentration of mercury vapor will be stable because the stabilized concentration becomes to be low and the stabilized time goes to be short as increased airflow rate. From KET and TCLP results, finally, phosphor powder should be managed as a hazardous waste but base-cap and glass are not classified as hazardous wastes. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Spectral filtering modulation method for estimation of hemoglobin concentration and oxygenation based on a single fluorescence emission spectrum in tissue phantoms.

    Science.gov (United States)

    Liu, Quan; Vo-Dinh, Tuan

    2009-10-01

    Hemoglobin concentration and oxygenation in tissue are important biomarkers that are useful in both research and clinical diagnostics of a wide variety of diseases such as cancer. The authors aim to develop simple ratiometric method based on the spectral filtering modulation (SFM) of fluorescence spectra to estimate the total hemoglobin concentration and oxygenation in tissue using only a single fluorescence emission spectrum, which will eliminate the need of diffuse reflectance measurements and prolonged data processing as required by most current methods, thus enabling rapid clinical measurements. The proposed method consists of two steps. In the first step, the total hemoglobin concentration is determined by comparing a ratio of fluorescence intensities at two emission wavelengths to a calibration curve. The second step is to estimate oxygen saturation by comparing a double ratio that involves three emission wavelengths to another calibration curve that is a function of oxygen saturation for known total hemoglobin concentration. Theoretical derivation shows that the ratio in the first step is linearly proportional to the total hemoglobin concentrations and the double ratio in the second step is related to both total hemoglobin concentration and hemoglobin oxygenation for the chosen fiber-optic probe geometry. Experiments on synthetic fluorescent tissue phantoms, which included hemoglobin with both constant and varying oxygenation as the absorber, polystyrene spheres as scatterers, and flavin adenine dinucleotide as the fluorophore, were carried out to validate the theoretical prediction. Tissue phantom experiments confirm that the ratio in the first step is linearly proportional to the total hemoglobin concentration and the double ratio in the second step is related to both total hemoglobin concentrations and hemoglobin oxygenation. Furthermore, the relations between the two ratios and the total hemoglobin concentration and hemoglobin oxygenation are insensitive

  11. Relative probabilities of the uranium isotopes for thorium x-ray emission and fluorescence of uranium x-rays

    International Nuclear Information System (INIS)

    Parker, J.L.

    1991-01-01

    Both thorium x-rays from decaying uranium isotopes and self-fluoresced uranium x-rays are prominent in high-resolution gamma-ray spectra of uranium-bearing materials. Useful application of the information carried by those x-rays has been curtailed because the probabilities of the uranium isotopes for thorium x-ray emission and for uranium x-ray fluorescence have not been known. By analyzing enrichment-meter geometry spectra from uranium oxide standards whose enrichments ranged from 0.7% to 91%, relative values, primarily, have been obtained for the probabilities of both processes. Thorium x-ray emission is very heavily dominated by 235 U. In all ordinarily occurring uranium isotopic distributions, thorium x-rays may be used as a valid 235 U signature. The probability for a thorium K α1 x-ray to be emitted in the decay of a 235 U atom is 0.048 ±0.002. In infinitely thick uranium oxide materials, the relative ratios of effectiveness for self-fluorescence, on a per unit mass basis, are approximately 234 U : 235 U : 236 U : 238 U = 1.13 : 1.00 : 0.52 : 0.028. on a per decay basis, the approximate ratios are 0.00039 : 1.00 : 0.017 : 0.18. These results imply that, contrary to what has often been stated, gamma rays are far more important than alpha particles in the self-fluorescence of uranium. Because of the importance of gamma-ray self-fluorescence, the uranium x-ray yield will be somewhat influenced by the size, shape, and composition of the materials. 4 refs., 1 fig

  12. Sensitivity of nitrogen dioxide concentrations to oxides of nitrogen controls in the United Kingdom

    International Nuclear Information System (INIS)

    Dixon, J.

    2001-01-01

    There is a possibility of further controls on emissions to the atmosphere of nitrogen dioxides to meet air quality objectives in the UK. Data in the National Air Quality Archive were used to calculate the likely sensitivity of hourly concentrations of nitrogen dioxide in ambient urban air to changes in the total oxides of nitrogen. Since the role of atmospheric chemical reactions is to make the responses non-linearly dependent on the emissions control, we seek to establish the magnitude and sign of the effects that this non-linearity might cause. We develop a quantitative approach to analysing the non-linearity in the data. Polynomial fits have been developed for the empirical ratio NO 2 :NO x (the 'yield'). They describe nitrogen dioxide concentrations using total oxides of nitrogen. The new functions have the important feature of increased yield in winter episodes. Simpler functions tend to omit this feature of the yields at the highest hourly concentrations. Based on this study, the hourly nitrogen dioxide objective in the UK may require emissions control of no more than about 50% on total oxides of nitrogen at the most polluted sites: other sites require less or even no control. (Author)

  13. Nitrogen oxides emissions from thermal power plants in china: current status and future predictions.

    Science.gov (United States)

    Tian, Hezhong; Liu, Kaiyun; Hao, Jiming; Wang, Yan; Gao, Jiajia; Qiu, Peipei; Zhu, Chuanyong

    2013-10-01

    Increasing emissions of nitrogen oxides (NOx) over the Chinese mainland have been of great concern due to their adverse impacts on regional air quality and public health. To explore and obtain the temporal and spatial characteristics of NOx emissions from thermal power plants in China, a unit-based method is developed. The method assesses NOx emissions based on detailed information on unit capacity, boiler and burner patterns, feed fuel types, emission control technologies, and geographical locations. The national total NOx emissions in 2010 are estimated at 7801.6 kt, of which 5495.8 kt is released from coal-fired power plant units of considerable size between 300 and 1000 MW. The top provincial emitter is Shandong where plants are densely concentrated. The average NOx-intensity is estimated at 2.28 g/kWh, markedly higher than that of developed countries, mainly owing to the inadequate application of high-efficiency denitrification devices such as selective catalytic reduction (SCR). Future NOx emissions are predicted by applying scenario analysis, indicating that a reduction of about 40% by the year 2020 can be achieved compared with emissions in 2010. These results suggest that NOx emissions from Chinese thermal power plants could be substantially mitigated within 10 years if reasonable control measures were implemented effectively.

  14. Emissions of nitric oxide from 79 plant species in response to simulated nitrogen deposition

    International Nuclear Information System (INIS)

    Chen Juan; Wu Feihua; Liu Tingwu; Chen Lei; Xiao Qiang; Dong Xuejun; He Junxian; Pei Zhenming; Zheng Hailei

    2012-01-01

    To assess the potential contribution of nitric oxide (NO) emission from the plants grown under the increasing nitrogen (N) deposition to atmospheric NO budget, the effects of simulated N deposition on NO emission and various leaf traits (e.g., specific leaf area, leaf N concentration, net photosynthetic rate, etc.) were investigated in 79 plant species classified by 13 plant functional groups. Simulated N deposition induced the significant increase of NO emission from most functional groups, especially from conifer, gymnosperm and C 3 herb. Moreover, the change rate of NO emission was significantly correlated with the change rate of various leaf traits. We conclude that the plants grown under atmospheric N deposition, especially in conifer, gymnosperm and C 3 herb, should be taken into account as an important biological source of NO and potentially contribute to atmospheric NO budget. - Highlights: ► Simulated N deposition induces the significant increase of NO emission from plants. ► The increased NO emission is closely related to leaf N level and net photosynthesis. ► Abundant nitrite accumulation is a reason of NO emission induced by excess N input. ► The plants grown under N deposition potentially contribute to atmospheric NO budget. - Simulated N deposition induced a significant increase of NO emission from 79 plants.

  15. 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

  16. Three-dimensional excitation and emission matrix fluorescence (3DEEM) for quick and pseudo-quantitative determination of protein- and humic-like substances in full-scale membrane bioreactor (MBR).

    Science.gov (United States)

    Jacquin, Céline; Lesage, Geoffroy; Traber, Jacqueline; Pronk, Wouter; Heran, Marc

    2017-07-01

    The goal of this study is to help filling the research gaps linked to the on-line application of fluorescence spectroscopy in wastewater treatment and data processing tools suitable for rapid correction and extraction of data contained in three-dimensional fluorescence excitation-emission matrix (3DEEM) for real-time studies. 3DEEM was evaluated for direct quantification of Effluent Organic Matter (EfOM) fractions in full-scale MBR bulk supernatant and permeate samples. Principal Component Analysis (PCA) was used to investigate possible correlations between conventional Lowry and Dubois methods, Liquid Chromatography coupled to Organic Carbon and Organic Nitrogen Detection (LC-OCD-OND) and 3DEEM. 3DEEM data were analyzed using the volume of fluorescence (Φ) parameter from the Fluorescence Regional Integration (FRI) method. Two mathematical correlations were established between LC-OCD-OND and 3DEEM data to quantify protein-like and humic-like substances. These correlations were validated with supplementary data from the initial full-scale MBR, and were checked with samples from other systems (a second full-scale MBR, a full-scale conventional activated sludge (CAS) and a laboratory-scale MBR). While humic-like correlation showed satisfactory prediction for a second full-scale MBR and a CAS system, further studies are required for protein-like estimation in other systems. This new approach offers interesting perspectives for the on-line application of 3DEEM for EfOM quantification (protein-like and humic-like substances), fouling prediction and MBR process control. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Efficient polymer white-light-emitting diodes with a single-emission layer of fluorescent polymer blend

    International Nuclear Information System (INIS)

    Niu Qiaoli; Xu Yunhua; Jiang Jiaxing; Peng Junbiao; Cao Yong

    2007-01-01

    Efficient polymer white-light-emitting diodes (WPLEDs) have been fabricated with a single layer of fluorescent polymer blend. The device structure consists of ITO/PEDOT/PVK/emissive layer/Ba/Al. The emissive layer is a blend of poly(9,9-dioctylfluorene) (PFO), phenyl-substituted PPV derivative (P-PPV) and a copolymer of 9,9-dioctylfluorene and 4,7-di(4-hexylthien-2-yl)-2,1,3-benzothiadiazole (PFO-DHTBT), which, respectively, emits blue, green and red light. The emission of pure and efficient white light was implemented by tuning the blend weight ratio of PFO: P-PPV: PFO-DHTBT to 96:4:0.4. The maximum current efficiency and luminance are, respectively, 7.6 cd/A at 6.7 V and 11930 cd/m 2 at 11.2 V. The CIE coordinates of white-light emission were stable with the drive voltages

  18. Nitrogen emissions during pyrolysis and combustion; Einfluesse auf die Stickstofffreisetzung bei der Pyrolyse und Verbrennung

    Energy Technology Data Exchange (ETDEWEB)

    Koepsel, R F; Friebel, J; Halang, S [Technische Univ. Bergakademie Freiberg (Germany). Inst. IEC

    1998-09-01

    Reduction of nitric oxide emissions during brown coal combustion is an important contribution to clean utilisation of this very important domestic primary energy source. In modern processes, the nitrogen contained in the fuels is the main source of oxides. The distribution of this nitrogen in the products can be influenced by modifying the degassing parameters especially in the first phase of combustion, i.e. pyrolysis. The heat-up rate, pressure, as well as the genesis and mineral content of the coal were found to be the main influencing paramters. Depending on the fuel characteristics (degree of coalification, concentration of volatile matter, ash composition), the nitrogen released during pyrolysis and the nitrogen retained in the solid residue contribute to the total emissions of nitric oxides in different degrees. (orig.) [Deutsch] Die Verminderung der Stickoxidemission bei der Verbrennung von Braunkohle stellt einen wichtigen Beitrag zur sauberen Verwertung dieses bedeutendsten einheimischen Primaerenergietraegers dar. In modernen Prozessen bildet dabei der im Brennstoff gebundene Stickstoff die Hauptquelle der Oxide. Insbesondere durch Einflussnahme auf die Entgasungsbedingungen waehrend der ersten Phase der Verbrennung - der Pyrolyse - kann die Verteilung dieses Stickstoffes auf die Produkte beeinflusst werden. Als wesentliche Einflussgroessen auf die Einbindung in den verbleibenden Koks und die Freisetzung fluechtiger N-haltiger Gase (HCN, NH{sub 3}) wurden die Aufheizgeschwindigkeit, der Druck und die Mineralsubstanz der Kohle gefunden. Eine wesentliche Einflussgroesse stellt daneben auch die Herkunft der Kohlen dar. In Abhaengigkeit von den Brennstoffeigenschaften (Inkohlungsgrad, Gehalt an fluechtigen Bestandteilen, Aschezusammensetzung) tragen der waehrend der Pyrolyse freigesetzte und der im festen Rueckstand verbleibende Stickstoff in unterschiedlichem Masse zur Gesamtemission an Stickoxiden bei. (orig.)

  19. Fluorescence excitation-emission matrix spectroscopy for degradation monitoring of machinery lubricants

    Science.gov (United States)

    Sosnovski, Oleg; Suresh, Pooja; Dudelzak, Alexander E.; Green, Benjamin

    2018-02-01

    Lubrication oil is a vital component of heavy rotating machinery defining the machine's health, operational safety and effectiveness. Recently, the focus has been on developing sensors that provide real-time/online monitoring of oil condition/lubricity. Industrial practices and standards for assessing oil condition involve various analytical methods. Most these techniques are unsuitable for online applications. The paper presents the results of studying degradation of antioxidant additives in machinery lubricants using Fluorescence Excitation-Emission Matrix (EEM) Spectroscopy and Machine Learning techniques. EEM Spectroscopy is capable of rapid and even standoff sensing; it is potentially applicable to real-time online monitoring.

  20. Interactions of Climate Change and Nitrogen Management for Optimizing Crop Productivity and Food Security while Minimizing Nitrogen Pollution and Greenhouse Gas Emissions

    Science.gov (United States)

    Davidson, E. A.; Suddick, E. C.

    2012-12-01

    Producing food, transportation, and energy for seven billion people has led to huge increases in use of synthetic nitrogen (N) fertilizers and fossil fuels, resulting in large releases of N as air and water pollution. In its numerous chemical forms, N plays a critical role in all aspects of climate change, including mitigation, adaptation, and impacts. Here we report on a multi-authored, interdisciplinary technical report on climate-nitrogen interactions submitted to the US National Climate Assessment as part of a Research Coordination Network activity. Management of the N cycle not only affects emissions of nitrous oxide (N2O) and nitrogen oxides (NOX), but also impacts carbon dioxide (CO2) and methane (CH4), through effects on carbon cycling processes in forests and soils and the effects on atmospheric reactions of ozone (O3) and CH4. While some of these direct and indirect N effects have a short-term cooling effect, the warming effects of N2O dominate at long time scales. The challenges of mitigating N2O emissions are substantially different from those for CO2 and CH4, because N is essential for food production, and over 80% of anthropogenic N2O emissions are from the agricultural sector. On one hand, improved agricultural nutrient management can confer some adaptive capacity of crops to climatic variability, but, on the other hand, increased climatic variability will render the task more difficult to manage nutrients for the optimization of crop productivity while minimizing N losses to the environment. Higher air temperatures will result in a "climate penalty" for air quality mitigation efforts, because larger NOX emissions reductions will be needed to achieve the same reductions of O3 pollution under higher temperatures, thus imposing further challenges to avoid harmful impacts on human health and crop productivity. Changes in river discharge, due to summer drought and to extreme precipitation events, will affect the transport of N from agricultural fields to

  1. High-efficiency electroluminescence and amplified spontaneous emission from a thermally activated delayed fluorescent near-infrared emitter

    Science.gov (United States)

    Kim, Dae-Hyeon; D'Aléo, Anthony; Chen, Xian-Kai; Sandanayaka, Atula D. S.; Yao, Dandan; Zhao, Li; Komino, Takeshi; Zaborova, Elena; Canard, Gabriel; Tsuchiya, Youichi; Choi, Eunyoung; Wu, Jeong Weon; Fages, Frédéric; Brédas, Jean-Luc; Ribierre, Jean-Charles; Adachi, Chihaya

    2018-02-01

    Near-infrared organic light-emitting diodes and semiconductor lasers could benefit a variety of applications including night-vision displays, sensors and information-secured displays. Organic dyes can generate electroluminescence efficiently at visible wavelengths, but organic light-emitting diodes are still underperforming in the near-infrared region. Here, we report thermally activated delayed fluorescent organic light-emitting diodes that operate at near-infrared wavelengths with a maximum external quantum efficiency of nearly 10% using a boron difluoride curcuminoid derivative. As well as an effective upconversion from triplet to singlet excited states due to the non-adiabatic coupling effect, this donor-acceptor-donor compound also exhibits efficient amplified spontaneous emission. By controlling the polarity of the active medium, the maximum emission wavelength of the electroluminescence spectrum can be tuned from 700 to 780 nm. This study represents an important advance in near-infrared organic light-emitting diodes and the design of alternative molecular architectures for photonic applications based on thermally activated delayed fluorescence.

  2. Inductively coupled plasma--atomic emission spectroscopy: an evaluation of the use of nitrogen--argon admixtures as plasma discharge atmospheres

    International Nuclear Information System (INIS)

    Zalewski, J.C.

    1979-01-01

    The effects of the use of nitrogen in either the plasma coolant or aerosol carrier gas flows on the physical and spectrochemical properties of the inductively coupled plasma (ICP) were examined. While the plasma operated with nitrogen in the coolant flow exhibited a stability comparable to that of the argon plasma, the use of nitrogen in the aerosol carrier gas flow resulted in a plasma that was less stable. The detection limits obtained for the three plasmas exhibited a similar trend. In addition, the use of nitrogen--argon admixtures in the plasma coolant gas flow yielded an increase in both the net analyte and the background emission intensities when the corresponding argon and nitrogen--argon plasmas were operated under various conditions. Furthermore, the effect of aluminum on the Ca II (393.4 nm) spectral line was reported for the 1000/1 Al/Ca molar ratio. At an observation height of 15 mm, the signal depressions were 4 and 14% for the nitrogen--argon and the argon plasmas, respectively. The above experimental evidence suggested that the operation of the ICP with an Ar--N 2 coolant gas might be hotter than the argon plasma currently in use in this laboratory. The demountable plasma torch designed in collaboration with K. Olson yielded detection limits for 15 elements and 19 spectral lines that were approximately within a factor of two of those obtained with the torch of fused quartz design. The design also appeared to offer a more readily initiated plasma discharge. The experimental evidence presented supports the utilization of nitrogen--argon admixtures in the plasma coolant gas flow as alternate discharge atmospheres for inductively coupled plasma--atomic emission spectroscopy. In contrast, the experimental evidence shows that there is a deterioration in both physical and spectrochemical properties of plasmas operated with a nitrogen aerosol carrier gas

  3. Compact fluorescent lighting in Wisconsin: elevated atmospheric emission and landfill deposition post-EISA implementation.

    Science.gov (United States)

    Arendt, John D; Katers, John F

    2013-07-01

    The majority of states in the USA, including Wisconsin, have been affected by elevated air, soil and waterborne mercury levels. Health risks associated with mercury increase from the consumption of larger fish species, such as Walleye or Pike, which bio-accumulate mercury in muscle tissue. Federal legislation with the 2011 Mercury and Air Toxics Standards and the Wisconsin legislation on mercury, 2009 Wisconsin Act 44, continue to aim at lowering allowable levels of mercury emissions. Meanwhile, mercury-containing compact fluorescent lights (CFL) sales continue to grow as businesses and consumers move away from energy intensive incandescent light bulbs. An exchange in pollution media is occurring as airborne mercury emissions from coal-burning power plants, the largest anthropogenic source of mercury, are being reduced by lower energy demand and standards, while more universal solid waste containing mercury is generated each time a CFL is disposed. The treatment of CFLs as a 'universal waste' by the Environmental Protection Agency (EPA) led to the banning of non-household fluorescent bulbs from most municipal solid waste. Although the EPA encourages recycling of bulbs, industry currently recycles fluorescent lamps and CFLs at a rate of only 29%. Monitoring programs at the federal and state level have had only marginal success with industrial and business CFL recycling. The consumer recycling rate is even lower at only 2%. A projected increase in residential CFL use in Wisconsin owing to the ramifications of the Energy Independence and Security Act of 2007 will lead to elevated atmospheric mercury and landfill deposition in Wisconsin.

  4. Characterization of waterborne nitrogen emissions for marine eutrophication modelling in life cycle impact assessment at the damage level and global scale

    DEFF Research Database (Denmark)

    Cosme, Nuno Miguel Dias; Hauschild, Michael Zwicky

    2017-01-01

    Current life cycle impact assessment (LCIA) methods lack a consistent and globally applicable characterization model relating nitrogen (N, as dissolved inorganic nitrogen, DIN) enrichment of coastal waters to the marine eutrophication impacts at the endpoint level. This paper introduces a method...... to calculate spatially explicit characterization factors (CFs) at endpoint and damage to ecosystems levels, for waterborne nitrogen emissions, reflecting their hypoxia-related marine eutrophication impacts, modelled for 5772 river basins of the world....

  5. Ultraviolet continuum and H2 fluorescent emission in Herbig-Haro objects 43 and 47

    International Nuclear Information System (INIS)

    Schwartz, R.D.

    1983-01-01

    The results of International Ultraviolet Explorer (IUE) short-wavelength spectra of the low-excitation Herbig-Haro objects HH 43 and HH 47 are reported. In HH 43 a number of emission lines in the Lyman band of H 2 from the excited state 1 μ + /sub u/, #betta#' = 1, J' = 4 are observed. The lines are produced by fluorescence from the H Lyα line which pumps the lower state 1 μ + /sub g/, #betta#'' = 2.J'' = 5 which in turn is excited by a low-velocity shock wave. No evidence of emission from highly ionized gas is present in the UV spectra. Both objects exhibit a UV continuum which peaks in the vicinity of 1500 A and which is probably caused by hydrogen two-photon emission enhanced by collisional excitation in a low-velocity shock

  6. Fluorescence properties of the anti-tumour alkaloid luotonin A and new synthetic analogues: pH modulation as an approach to their fluorimetric quantitation in biological samples

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Ruiz, Victor; Gonzalez-Cuevas, Yamisley; Arunachalam, Sankaralingam [S. D. Quimica Analitica, Facultad de Farmacia, Universidad Complutense de Madrid, 28040-Madrid (Spain); Martin, M. Antonia, E-mail: mantonia@farm.ucm.es [S. D. Quimica Analitica, Facultad de Farmacia, Universidad Complutense de Madrid, 28040-Madrid (Spain); Olives, Ana I. [S. D. Quimica Analitica, Facultad de Farmacia, Universidad Complutense de Madrid, 28040-Madrid (Spain); Ribelles, Pascual; Ramos, M. Teresa; Menendez, J. Carlos [D. Quimica Organica y Farmaceutica, Facultad de Farmacia, Universidad Complutense de Madrid, 28040-Madrid (Spain)

    2012-09-15

    Luotonin A is an alkaloid structurally related to the natural anti-tumour agent camptothecin. The fluorescence behaviour of luotonin A and a series of six analogues is described in the present work. The influence of solvent polarity and pH on the native fluorescence properties of these alkaloids was studied, finding that in organic solvents or in aqueous solutions (pH 5.5-7.2) the neutral form of the luotonin derivatives emit in the region of 410-450 nm but, in both media, acidification to pH values below 3.0 causes a new emission band to appear at about 500 nm. An ESPT reaction occurs due to the protonation of the basic nitrogen atoms of the pentacyclic ring. Acid-base titrations of luotonin A and its derivatives in aqueous and acetonitrile media were carried out in order to determine their pK{sub a}{sup Low-Asterisk} values which were around 2, showing these compounds to be very weak bases. In aqueous media, the absence of an iso-emissive point in the emission spectra suggests the existence of more than two species in the proton transfer equilibria. The basicity of the luotonin A derivatives is increased in organic media, and a good correlation between the pK{sub a}{sup Low-Asterisk} values and the chemical structure was found. The protonation of luotonin A was also studied by {sup 1}H-NMR and {sup 13}C-NMR experiments, which proved the protonation of the nitrogen atoms at the positions 5 and 6 of the pentacyclic ring. The fluorescence quantum yields were determined in ethanol and in aqueous solutions under neutral and acidic conditions. The fluorescence quantum yields were higher in water for the case of the more polar compounds, and the opposite result was obtained for the more hydrophobic ones. The remarkable and interesting fluorescence properties of luotonin A prompted the development of its fluorimetric analytical quantitation, obtaining very good analytical features. - Highlights: Black-Right-Pointing-Pointer This is the first study on the fluorescence

  7. Field emission of carbon quantum dots synthesized from a single organic solvent.

    Science.gov (United States)

    Liu, Xiahui; Yang, Bingjun; Yang, Juan; Yu, Shengxue; Chen, Jiangtao

    2016-11-04

    In this paper, a facile synthesis of carbon quantum dots (CQDs) and its field emission performance are reported. The CQDs are prepared from a single N, N-dimethylformamide acting as carbon and nitrogen-doping sources simultaneously. The CQDs are investigated by photoluminescence, transmission electron microscopy and x-ray photoelectron spectroscopy. The CQDs have an average size of 3 nm and are doped with N atoms. CQD dispersion shows strong fluorescence under UV illumination. For the first time, the field emission behavior of CQDs coated on Si substrate is studied. As a candidate of cold cathode, the CQDs display good field emission performance. The CQD emitter reaches the current density of 1.1 mA cm(-2) at 7.0 V μm(-1) and exhibits good long-term emission stability, suggesting promising application in field emission devices.

  8. Nitrous oxide emissions from a golf course fairway and rough following application of different nitrogen fertilizers

    Science.gov (United States)

    Nitrous oxide (N2O) is a potent greenhouse gas that destroys stratospheric ozone. There is limited research of golf course N2O emission and the effects of frequent fertilization and irrigation. Three enhanced efficiency nitrogen fertilizers (EENFs) were applied to a Colorado golf course fairway and ...

  9. Experimental study of reduce of nitrogen oxides emission in the Environment at the Ekibastuz coal combustion

    International Nuclear Information System (INIS)

    Korabejnikova, V.K.

    2004-01-01

    For revealing conditions decrease in emissions of nitrogen oxide in an environment at three-stage burning of coal dust Ekibastuz coal with use two-line burners (on were the experimental research of test on fiery the stand as a result of which acknowledgement of theoretical results is received. (author)

  10. Spatial and Temporal Trends in Global Emissions of Nitrogen Oxides from 1960 to 2014.

    Science.gov (United States)

    Huang, Tianbo; Zhu, Xi; Zhong, Qirui; Yun, Xiao; Meng, Wenjun; Li, Bengang; Ma, Jianmin; Zeng, Eddy Y; Tao, Shu

    2017-07-18

    The quantification of nitrogen oxide (NO x ) emissions is critical for air quality modeling. Based on updated fuel consumption and emission factor databases, a global emission inventory was compiled with high spatial (0.1° × 0.1°), temporal (monthly), and source (87 sources) resolutions for the period 1960 to 2014. The monthly emission data have been uploaded online ( http://inventory.pku.edu.cn ), along with a number of other air pollutant and greenhouse gas data for free download. Differences in source profiles, not global total quantities, between our results and those reported previously were found. There were significant differences in total and per capita emissions and emission intensities among countries, especially between the developing and developed countries. Globally, the total annual NO x emissions finally stopped increasing in 2013 after continuously increasing over several decades, largely due to strict control measures taken in China in recent years. Nevertheless, the peak year of NO x emissions was later than for many other major air pollutants. Per capita emissions, either among countries or over years, follow typical inverted U-shaped environmental Kuznets curves, indicating that the emissions increased during the early stage of development and were restrained when socioeconomic development reached certain points. Although the trends are similar among countries, the turning points of developing countries appeared sooner than those of developed countries in terms of development status, confirming late-move advantages.

  11. Activities of the All-Union Institute for Heat Technology in suppression of nitrogen oxide emission by technological methods

    Energy Technology Data Exchange (ETDEWEB)

    Enyakin, Yu.P.; Kotler, V.R.; Babii, V.I.; Shtal' man, S.G.; Shcherbachenko, S.I. (Vsesoyuznyi Teplotekhnicheskii Institut (USSR))

    1991-06-01

    Evaluates research programs of the All-Union Institute for Heat Technology in the USSR from 1970 to 1991. Research and development programs, developed technologies or equipment types, their tests and use on a commercial scale are discussed. Power plants in the USSR which use the technologies are listed. The following technologies are comparatively evaluated: recirculation of flue gases to a combustion system (reduces emission of nitrogen oxides by about 2 times), two-stage coal combustion (reduces emission by 40-50%), three-stage combustion (reduces emission by 40-50%), use of special types of burners (reduces emission by 25-30%), adapting temperature of air supplied to the combustion zone (reduces emission by 20-30%). 10 refs.

  12. Nanoantenna array-induced fluorescence enhancement and reduced lifetimes

    DEFF Research Database (Denmark)

    Bakker, R. M.; Drachev, V. P.; Liu, Z.

    2008-01-01

    Enhanced fluorescence is observed from dye molecules interacting with optical nanoantenna arrays. Elliptical gold dimers form individual nanoantennae with tunable plasmon resonances depending upon the geometry of the two particles and the size of the gap between them. A fluorescent dye, Rhodamine...... 800, is uniformly embedded in a dielectric host that coats the nanoantennae. The nanoantennae act to enhance the dye absorption. In turn, emission from the dye drives the plasmon resonance of the antennae; the nanoantennae act to enhance the fluorescence signal and change the angular distribution...... of emission. These effects depend upon the overlap of the plasmon resonance with the excitation wavelength and the fluorescence emission band. A decreased fluorescence lifetime is observed along with highly polarized emission that displays the characteristics of the nanoantenna's dipole mode. Being able...

  13. An “on-off-on” fluorescent nanoprobe for recognition of chromium(VI) and ascorbic acid based on phosphorus/nitrogen dual-doped carbon quantum dot

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Xiaojuan, E-mail: gxj1124@sxu.edu.cn [Institute of Environmental Science, School of Chemistry and Chemical Engineering, Shanxi University, Taiyuan 030006 (China); Liu, Yang; Yang, Zhenhua; Shuang, Shaomin [Institute of Environmental Science, School of Chemistry and Chemical Engineering, Shanxi University, Taiyuan 030006 (China); Zhang, Zeyu [Faculty of Science, Beijing University of Chemical Technology, Beijing, 100029 (China); Dong, Chuan, E-mail: dc@sxu.edu.cn [Institute of Environmental Science, School of Chemistry and Chemical Engineering, Shanxi University, Taiyuan 030006 (China)

    2017-05-22

    Chromium (VI) [Cr(VI)] is a harsh environmental contaminates and has been proved to be highly toxic, carcinogenic and mutagenic. Therefore, developing an inexpensive, good selective and highly sensitive nanoprobe for the detection of Cr(VI) is in urgent demand. Recently, the highly fluorescent carbon quantum dots (CQDs) have been successfully utilized as efficient fluorescent nanoprobes for the detection of ions, pH and molecular substances. In this work, an “on-off” fluorescence phosphorus/nitrogen dual-doped CQDs (PNCQDs) probe was developed for the determination of Cr(VI) based on inner filter effect (IFE). The proposed PNCQDs nanoprobe shows its distinct merits of simplicity, convenience, fast implementation, good selectivity and high sensitivity towards Cr(VI), allowing its potential application in the determination of Cr(VI) in environment and biosystem. In addition, the chelation effect of the functional groups in reductant and Cr(VI), and the easy-conversion of Cr(VI) to reduced states (i.e. Cr(III) and Cr(0)) by reductants makes the minimization of IFE with a concomitant recovery of PNCQDs fluorescence possible. Hence, the PNCQDs/Cr(VI) hybrid was used as an “off-on” fluorescence probe for sensing ascorbic acid (AA), which is a model reductant. For the detection of Cr(VI), the linear range and the limit of detection achieved were 1.5–30 μmol/L and 23 nmol/L, respectively. For the detection of AA, the linear range and the limit of detection obtained were 5.0–200 μmol/L and 1.35 μmol/L, respectively. The as-constructed “on-off-on” PNCQDs fluorescent nanoprobe was successfully applied for detecting Cr(VI) and AA in biosystem. Furthermore, the as-constructed fluorescent sensing system was successfully applied to the analyses of AA in fresh fruits and in commercial fruit juices with satisfactory results. - Highlights: • Fast synthesis of phosphorus/nitrogen dual-doped CQDs (PNCQDs) by acid-base neutralization carbonization method.

  14. Emission characteristics of nitrogen- and sulfur-containing odorous compounds during different sewage sludge chemical conditioning processes

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Huan [State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan 430074 (China); School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Luo, Guang-Qian; Hu, Hong-Yun [State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan 430074 (China); Zhang, Qiang; Yang, Jia-Kuan [School of Environmental Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Yao, Hong, E-mail: hyao@hust.edu.cn [State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2012-10-15

    Highlights: Black-Right-Pointing-Pointer NH{sub 3}, SO{sub 2}, H{sub 2}S and COS are emitted during different sludge conditioning processes. Black-Right-Pointing-Pointer H{sub 2}S and SO{sub 2} generation increase in the acidic environment created by H{sub 2}SO{sub 4}. Black-Right-Pointing-Pointer Fenton peroxidation facilitates the formation of COS. Black-Right-Pointing-Pointer CaO can reduce sulfur-containing gases emission via generation of calcium sulfate. Black-Right-Pointing-Pointer CaO leads to the conversion of free ammonia or protonated amine to volatile NH{sub 3}. - Abstract: Chemical conditioners are often used to enhance sewage sludge dewaterability through altering sludge properties and flocs structure, both affect odorous compounds emissions not only during sludge conditioning but also in subsequent sludge disposal. This study was to investigate emission characteristics of ammonia (NH{sub 3}), sulfur dioxide (SO{sub 2}), hydrogen sulfide (H{sub 2}S) and carbonyl sulfide (COS) generated from sewage sludge conditioned by three representative conditioners, i.e., organic polymers, iron salts and skeleton builders, F-S (Fenton's reagent and skeleton builders) composite conditioner. The results demonstrate that polyacrylamide (PAM) has an insignificant effect on emission characteristics of nitrogen- and sulfur-containing odorous compounds, because the properties, sulfur and nitrogen speciations are similar in PAM-conditioned sludge and raw sludge (RS). Significant increases of SO{sub 2} and H{sub 2}S emissions in the H{sub 2}SO{sub 4} conditioning process were observed due to the accelerated decomposition of sulfur-containing amino acids in acidic environment. Fenton peroxidation facilitates the formation of COS. CaO can reduce sulfur-containing gases emission via generation of calcium sulfate. However, under strong alkaline conditions, free ammonia or protonated amine in sludge can be easily converted to volatile ammonia, resulting in a significant

  15. Nitrogen management impacts nitrous oxide emissions under varying cotton irrigation systems in the American Desert Southwest

    Science.gov (United States)

    Irrigation of food and fiber crops worldwide continues to increase. Nitrogen (N) from fertilizers is a major source of the potent greenhouse gas nitrous oxide (N2O) in irrigated cropping systems. Nitrous oxide emissions data are scarce for crops in the arid Western US. The objective of these studies...

  16. Nitrogen source effects on nitrous oxide emissions from irrigated no-till corn.

    Science.gov (United States)

    Halvorson, Ardell D; Del Grosso, Stephen J; Francesco, Alluvione

    2010-01-01

    Nitrogen fertilization is essential for optimizing crop yields; however, it may potentially increase nitrous oxide (N2O) emissions. The study objective was to assess the ability of commercially available enhanced-efficiency N fertilizers to reduce N2O emissions following their application in comparison with conventional dry granular urea and liquid urea-ammonium nitrate (UAN) fertilizers in an irrigated no-till (NT) corn (Zea mays L.) production system. Four enhanced-efficiency fertilizers were evaluated: two polymer-coated urea products (ESN and Duration III) and two fertilizers containing nitrification and urease inhibitors (SuperU and UAN+AgrotainPlus). Nitrous oxide fluxes were measured during two growing seasons using static, vented chambers and a gas chromatograph analyzer. Enhanced-efficiency fertilizers significantly reduced growing-season N2O-N emissions in comparison with urea, including UAN. SuperU and UAN+AgrotainPlus had significantly lower N2O-N emissions than UAN. Compared with urea, SuperU reduced N2O-N emissions 48%, ESN 34%, Duration III 31%, UAN 27%, and UAN+AgrotainPlus 53% averaged over 2 yr. Compared with UAN, UAN+AgrotainPlus reduced N2O emissions 35% and SuperU 29% averaged over 2 yr. The N2O-N loss as a percentage of N applied was 0.3% for urea, with all other N sources having significantly lower losses. Grain production was not reduced by the use of alternative N sources. This work shows that enhanced-efficiency N fertilizers can potentially reduce N2O-N emissions without affecting yields from irrigated NT corn systems in the semiarid central Great Plains.

  17. Atmospheric emission of nitrogen oxide from kraft recovery boilers in Sweden

    International Nuclear Information System (INIS)

    Kjoerk, Anders; Herstad Swaerd, Solvie

    2000-05-01

    Recovery boiler NO x emissions are low compared with those from power boilers. However tighter environmental requirements to decrease the acidic emissions implies that all sources have to be addressed. There are an ongoing evaluation and development of NO x control technologies in the pulp industry. Basically air staging, selective catalytic reduction, SCR, and selective noncatalytic reduction, SNCR, have been discussed. Other NO x control options may be available as a result of ongoing research and development. As a background in the work to reduce the acid rain it has been considered necessary to have a good picture of the NO x emission from recovery boilers, and the Thermal Engineering Research Institute in Sweden have therefore sponsored this study. The intention is to give a good general view and try to explain the reasons for the large differences between boilers. Data from the 30 kraft recovery boilers which were in operation in Sweden during 1999 have been collected. Both NO x levels and specific conditions which could have an influence on the level have been included. The evaluation show a clear correlation between the nitrogen content in the liquor and the NO x level. It seams also that a long retention time in the furnace give an opportunity to reduce the amount of nitrogen oxide. For most boilers in Sweden the NO x levels are reported in mg/MJ and comparison could be done between different types of boilers. However for recovery boilers there could be a large uncertainty in the calculation which gives the amount (mg) of NO x , the definition of the heat input to be used (MJ) is either not clear. As a base for the study the measured concentration in ppm is used instead. The reported values are in the range of 30 - 100 ppm, however the majority of the boilers operate in a more narrow range 60-80 ppm. Air staging and other combustion methods could not reasonably reduce the NO x emission with more than 20% in the next decade. If the goal is higher other

  18. Demonstrating Fluorescence with Neon Paper and Plastic

    Science.gov (United States)

    Birriel, Jennifer J.; Roe, Clarissa

    2015-01-01

    Several papers in this journal have dealt with the fluorescence in orange neon plastic, olive oil, and soda. In each case, the fluorescent emission was excited by either green or violet-blue laser light. In this paper, we examine the fluorescent emission spectra of so-called neon colored papers and plastic clipboards available in department and…

  19. Nitrogen source effects on soil nitrous oxide emissions from strip-till corn.

    Science.gov (United States)

    Halvorson, Ardell D; Del Grosso, Stephen J; Jantalia, Claudia Pozzi

    2011-01-01

    Nitrogen (N) application to crops generally results in increased nitrous oxide (NO) emissions. Commercially available, enhanced-efficiency N fertilizers were evaluated for their potential to reduce NO emissions from a clay loam soil compared with conventionally used granular urea and urea-ammonium nitrate (UAN) fertilizers in an irrigated strip-till (ST) corn ( L.) production system. Enhanced-efficiency N fertilizers evaluated were a controlled-release, polymer-coated urea (ESN), stabilized urea, and UAN products containing nitrification and urease inhibitors (SuperU and UAN+AgrotainPlus), and UAN containing a slow-release N source (Nfusion). Each N source was surface-band applied (202 kg N ha) at corn emergence and watered into the soil the next day. A subsurface-band ESN treatment was included. Nitrous oxide fluxes were measured during two growing seasons using static, vented chambers and a gas chromatograph analyzer. All N sources had significantly lower growing season NO emissions than granular urea, with UAN+AgrotainPlus and UAN+Nfusion having lower emissions than UAN. Similar trends were observed when expressing NO emissions on a grain yield and N uptake basis. Loss of NO-N per kilogram of N applied was <0.8% for all N sources. Corn grain yields were not different among N sources but greater than treatments with no N applied. Selection of N fertilizer source can be a mitigation practice for reducing NO emissions in strip-till, irrigated corn in semiarid areas. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  20. Substantial nitrogen pollution embedded in international trade

    Science.gov (United States)

    Oita, Azusa; Malik, Arunima; Kanemoto, Keiichiro; Geschke, Arne; Nishijima, Shota; Lenzen, Manfred

    2016-02-01

    Anthropogenic emissions of reactive nitrogen to the atmosphere and water bodies can damage human health and ecosystems. As a measure of a nation’s contribution to this potential damage, a country’s nitrogen footprint has been defined as the quantity of reactive nitrogen emitted during the production, consumption and transportation of commodities consumed within that country, whether those commodities are produced domestically or internationally. Here we use global emissions databases, a global nitrogen cycle model, and a global input-output database of domestic and international trade to calculate the nitrogen footprints for 188 countries as the sum of emissions of ammonia, nitrogen oxides and nitrous oxide to the atmosphere, and of nitrogen potentially exportable to water bodies. Per-capita footprints range from under 7 kg N yr-1 in some developing countries to over 100 kg N yr-1 in some wealthy nations. Consumption in China, India, the United States and Brazil is responsible for 46% of global emissions. Roughly a quarter of the global nitrogen footprint is from commodities that were traded across country borders. The main net exporters have significant agricultural, food and textile exports, and are often developing countries, whereas important net importers are almost exclusively developed economies. We conclude that substantial local nitrogen pollution is driven by demand from consumers in other countries.

  1. Energy balance and greenhouse gas emissions of dryland camelina as influenced by tillage and nitrogen

    International Nuclear Information System (INIS)

    Keshavarz-Afshar, Reza; Mohammed, Yesuf Assen; Chen, Chengci

    2015-01-01

    Despite the great potential of camelina (Camelina sativa L. Crantz) as a promising biofuel feedstock, in-farm energy flow of the crop and its associated environmental impacts has not received sufficient attention from researchers. In order to assess net energy gain and to identify energy saving and environmental friendly production operations, a two year study was conducted at central Montana. We investigated the effects of tillage method (CT (conventional tillage) vs. NT (no-tillage)) and N (nitrogen) fertilizer rate (0, 45, 90 kg N ha −1 ) on energy balance and GHG (greenhouse gas emission) of dryland camelina production. Results indicated that energy input and GHG emission were 5 and 8% lower in NT than in CT. Application of 45 and 90 kg N ha −1 increased camelina energy input by 186 and 365%, while increased energy output by only 21 and 64%, respectively. There was no significant difference in net energy gain in response to N fertilization, but lower energy efficiency in response to higher N inputs. Averaged across tillage systems, the GHG emission was 32.0 kg C eq ha −1 with 0 N applied, and the GHG emission increased by 206 and 389% when 45 and 90 kg N ha −1 was applied. Overall, N fertilizer had the biggest share in total energy input. Averaged over all experimental treatments, 14,945 MJ ha −1 net energy was obtained from camelina crop in this study which shows the potential of this crop as a bioenergy feedstock. Our result showed that implementation of NT is strongly recommendable for camelina production in this region. Moreover, improvement of N use efficiency has the highest priority to improve energy performance and reduce GHG emissions in camelina production. - Highlights: • Camelina produced 14,945 MJ ha −1 of net energy in this study. • No tillage operation reduced 5% energy input and 8% greenhouse gas emission. • Nitrogen fertilizer was the most energy-intensive input in camelina production.

  2. Precise measurement of the absolute fluorescence yield of nitrogen in air. Consequences on the detection of ultra-high energy cosmic rays; Mesure precise du rendement absolu de la fluorescence de l'azote dans l'air. Consequences sur la detection des rayons cosmiques d'ultra-haute energie

    Energy Technology Data Exchange (ETDEWEB)

    Lefeuvre, G

    2006-07-15

    The study of the energy spectrum of ultra-high energy cosmic rays (E > 10{sup 20} eV) requires to determine the energy with much more precision than what is currently achieved. The shower of particles created in the atmosphere can be detected either by sampling particle on the ground, or by detecting the fluorescence induced by the excitation of nitrogen by shower electrons. At present, the measurement of the fluorescence is the simplest and the most reliable method, since it does not call upon hadronic physics laws at extreme energies, a field still inaccessible to accelerators. The precise knowledge of the conversion factor between deposited energy and the number of fluorescence photons produced (the yield) is thus essential. Up to now, it has been determined with an accuracy of 15 % only. This main goal of this work is to measure this yield to better than 5 per cent. To do this, 1 MeV electrons from a radioactive source excite nitrogen of the air. The accuracy has been reached thanks to the implementation of a new method for the absolute calibration of the photomultipliers detecting the photons, to better than 2 per cent. The fluorescence yield, measured and normalized to 0.85 MeV, 760 mmHg and 15 Celsius degrees, is (4.23 {+-} 0.20) photons per meter, or (20.46 {+-} 0.98) photons per deposited MeV. In addition, and for the first time, the absolute fluorescence spectrum of nitrogen excited by a source has been measured with an optical grating spectrometer. (author)

  3. Nitrogen Cycling and GHG Emissions of Natural and Managed Tropical Ecosystems at Mt. Kilimanjaro

    Science.gov (United States)

    Gutlein, A.; Ralf, K.; Gerschlauer, F.; Dannenmann, M.; Butterbach-Bahl, K.; Diaz-Pines, E.

    2016-12-01

    In a rapidly changing world understanding of natural ecosystems response to human perturbations such as land use and climate changes as well as habitat destruction is crucial with respect to sustainability of ecosystem services. This is particularily true for tropical forest ecosystems which have significant effects on the major biogeochemical cycles and global climate. Here we present a comprehensive dataset of nitrogen cycling and GHG emissions of natural and managed ecosystems along land use and climate gradients at Mt. Kilimanjaro, Tanzania including different forest ecosystems, homegardens, and coffee plantations. Soil N turnover rates were highest in the Ocotea forest and progressively decreased with decreasing annual rainfall and increasing land use intensity. Nitrogen production and immobilization rates positively correlated with soil organic C and total N concentrations as well as substrate availability of dissolved organic C and N, but correlated less with soil ammonium and nitrate concentrations. By using indicators of N retention and characteristics of soil nutrient status, we observed a grouping of faster, but tighter N cycling in the (semi-) natural savanna, Helychrysum and Ocotea forest. This contrasted with a more open N cycle in managed systems (homegarden and coffee plantation) where N was more prone to leaching or gaseous losses due to high nitrate production rates. The partly disturbed lower montane forest ranged in between these two groups. These finding could be supported by differences in natural 15N abundance of litter and soil across all sites. Comparing GHG emissions at the land use gradient showed, that with increasing intensification (lower montane forest - homegarden - coffee plantation) N2O emissions increased but at the same time the soil sink for atmospheric CH4 decreased. GHG emission measurements at the climate gradient (savanna, lower montane, Ocotea and Podocarpus forest, Helychrysum) revealed that differences in soil moisture

  4. Water regime-nitrogen fertilizer incorporation interaction: Field study on methane and nitrous oxide emissions from a rice agroecosystem in Harbin, China.

    Science.gov (United States)

    Dong, Wenjun; Guo, Jia; Xu, Lijun; Song, Zhifeng; Zhang, Jun; Tang, Ao; Zhang, Xijuan; Leng, Chunxu; Liu, Youhong; Wang, Lianmin; Wang, Lizhi; Yu, Yang; Yang, Zhongliang; Yu, Yilei; Meng, Ying; Lai, Yongcai

    2018-02-01

    Water regime and nitrogen (N) fertilizer are two important factors impacting greenhouse gases (GHG) emission from paddy field, whereas their effects have not been well studied in cold region. In this study, we conducted a two-year field experiment to study the impacts of water regime and N fertilizer on rice yields and GHG emissions in Harbin, China, a cold region located in high latitudes. Our results showed that intermittent irrigation significantly decreased methane (CH 4 ) emission compared with continuous flooding, however, the decrement was far lower than the global average level. The N 2 O emissions were very small when flooded but peaked at the beginning of the disappearance of floodwater. The N fertilizer treatments increased CH 4 emissions at low level (75kgN/ha). But both CH 4 and N 2 O emissions were uninfluenced at the levels of 150kgN/ha and 225kgN/ha. Rice yields increased under intermittent irrigation and were highest at the level of 150kgN/ha. From our results, we recommended that the intermittent irrigation and 150kgN/ha as the ideal water regime-nitrogen fertilizer incorporation for this area to achieve low GHG emissions without impacting rice yields. Copyright © 2017. Published by Elsevier B.V.

  5. Development of a Xanthene-Based Red-Emissive Fluorescent Probe for Visualizing H2O2 in Living Cells, Tissues and Animals.

    Science.gov (United States)

    Zhang, Nan; Dong, Baoli; Kong, Xiuqi; Wang, Chao; Song, Wenhui; Lin, Weiying

    2018-04-25

    Hydrogen peroxide (H 2 O 2 ) plays important roles in the regulation of many biological processes, and the abnormal level of H 2 O 2 has close relation with the initiation and progression of many diseases. Herein, we describe a novel red-emissive fluorescence probe (RhoB) for the visualization of H 2 O 2 in living cells, tissues and animals. RhoB was constructed on the basis of a xanthene-based red-emissive dye, and displayed nearly no fluorescence. After the treatment with H 2 O 2 , RhoB can exhibit red fluorescence with the emission wavelength at 638 nm. RhoB exhibited highly sensitive and selective response to H 2 O 2 . Density functional theory (DFT) calculations were conducted to shed light on the optical properties of RhoB, and natural bond orbital (NBO) calculations demonstrate that the boron atom shows the highest positive electricity and further support the response mechanism. RhoB was successfully applied for imaging of exogenous and endogenous H 2 O 2 in living cells, and also can be utilized for visualizing H 2 O 2 in living tissues and animals.

  6. Fluorescence intensity dependence on the propagation plane inclination

    International Nuclear Information System (INIS)

    Fernandez, J.E.; Rubio, Marcelo; Sanchez, H.J.

    1987-01-01

    A theoretical study of the emission from layers of primary and secondary fluorescent components for a sample of infinite thickness was made, finding out that this emission depends mainly on the α angle as a maximum emission selector of a certain layer, which means 'tuning' the fluorescent radiation that comes primarily from a certain depth. These results can be applied to the study of both selective emission by layers and to the selection of superficial fluorescence. The analytical results have been confirmed by a Monte Carlo simulation. (Author) [es

  7. Nitrogen-rich functional groups carbon nanoparticles based fluorescent pH sensor with broad-range responding for environmental and live cells applications.

    Science.gov (United States)

    Shi, Bingfang; Su, Yubin; Zhang, Liangliang; Liu, Rongjun; Huang, Mengjiao; Zhao, Shulin

    2016-08-15

    A nitrogen-rich functional groups carbon nanoparticles (N-CNs) based fluorescent pH sensor with a broad-range responding was prepared by one-pot hydrothermal treatment of melamine and triethanolamine. The as-prepared N-CNs exhibited excellent photoluminesence properties with an absolute quantum yield (QY) of 11.0%. Furthermore, the N-CNs possessed a broad-range pH response. The linear pH response range was 3.0 to 12.0, which is much wider than that of previously reported fluorescent pH sensors. The possible mechanism for the pH-sensitive response of the N-CNs was ascribed to photoinduced electron transfer (PET). Cell toxicity experiment showed that the as-prepared N-CNs exhibited low cytotoxicity and excellent biocompatibility with the cell viabilities of more than 87%. The proposed N-CNs-based pH sensor was used for pH monitoring of environmental water samples, and pH fluorescence imaging of live T24 cells. The N-CNs is promising as a convenient and general fluorescent pH sensor for environmental monitoring and bioimaging applications. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Monitoring the Behavior of Emerging Contaminants in Wastewater-Impacted Rivers Based on the Use of Fluorescence Excitation Emission Matrixes (EEM).

    Science.gov (United States)

    Sgroi, Massimiliano; Roccaro, Paolo; Korshin, Gregory V; Vagliasindi, Federico G A

    2017-04-18

    This study investigated the applicability of fluorescence indexes based on the interpretation of excitation emission matrices (EEMs) by PARAFAC analysis and by selecting fluorescence intensities at a priori defined excitation/emission pairs as surrogates for monitoring the behavior of emerging organic compounds (EOCs) in two catchment basins impacted by wastewater discharges. Relevant EOC and EEM data were obtained for a 90 km stretch of the Simeto River, the main river in Sicily, and the smaller San Leonardo River, which was investigated for a 17 km stretch. The use of fluorescence indexes developed by these two different approaches resulted in similar observations. Changes of the fluorescence indexes that correspond to a group of humic-like fluorescing species were determined to be highly correlated with the concentrations of recalcitrant contaminants such as sucralose, sulfamethoxazole and carbamazepine, which are typical wastewater markers in river water. Changes of the fluorescence indexes related to tyrosine-like substances were well correlated with the concentrations of ibuprofen and caffeine, anthropogenic indicators of untreated wastewater discharges. Chemical oxygen demand and dissolved organic carbon concentrations were correlated with humic-like fluorescence indexes. The observed correlations were site-specific and characterized by different regression parameters for every collection event. Caffeine and carbamazepine showed correlations with florescence indexes in the San Leonardo River and in the alluvial plain stretch of the Simeto River, whereas sucralose, sulfamethoxazole and ibuprofen have always been well correlated in all the investigated river stretches. However, when data of different collection events from river stretches where correlations were observed were combined, good linear correlations were obtained for data sets generated via the normalization of the measured concentrations by the average value for the corresponding collection event

  9. Selective detection of Mg2+ ions via enhanced fluorescence emission using Au–DNA nanocomposites

    Directory of Open Access Journals (Sweden)

    Tanushree Basu

    2017-04-01

    Full Text Available The biophysical properties of DNA-modified Au nanoparticles (AuNPs have attracted a great deal of research interest for various applications in biosensing. AuNPs have strong binding capability to the phosphate and sugar groups in DNA, rendering unique physicochemical properties for detection of metal ions. The formation of Au–DNA nanocomposites is evident from the observed changes in the optical absorption, plasmon band, zeta potential, DLS particle size distribution, as well as TEM and AFM surface morphology analysis. Circular dichroism studies also revealed that DNA-functionalized AuNP binding caused a conformational change in the DNA structure. Due to the size and shape dependent plasmonic interactions of AuNPs (33–78 nm with DNA, the resultant Au–DNA nanocomposites (NCs exhibit superior fluorescence emission due to chemical binding with Ca2+, Fe2+ and Mg2+ ions. A significant increase in fluorescence emission (λex = 260 nm of Au–DNA NCs was observed after selectively binding with Mg2+ ions (20–800 ppm in an aqueous solution where a minimum of 100 ppm Mg2+ ions was detected based on the linearity of concentration versus fluorescence intensity curve (λem = 400 nm. The effectiveness of Au–DNA nanocomposites was further verified by comparing the known concentration (50–120 ppm of Mg2+ ions in synthetic tap water and a real life sample of Gelusil (300–360 ppm Mg2+, a widely used antacid medicine. Therefore, this method could be a sensitive tool for the estimation of water hardness after careful preparation of a suitably designed Au–DNA nanostructure.

  10. Achieving Lower Nitrogen Balance and Higher Nitrogen Recovery Efficiency Reduces Nitrous Oxide Emissions in North America's Maize Cropping Systems

    Directory of Open Access Journals (Sweden)

    Rex A. Omonode

    2017-06-01

    Full Text Available Few studies have assessed the common, yet unproven, hypothesis that an increase of plant nitrogen (N uptake and/or recovery efficiency (NRE will reduce nitrous oxide (N2O emission during crop production. Understanding the relationships between N2O emissions and crop N uptake and use efficiency parameters can help inform crop N management recommendations for both efficiency and environmental goals. Analyses were conducted to determine which of several commonly used crop N uptake-derived parameters related most strongly to growing season N2O emissions under varying N management practices in North American maize systems. Nitrogen uptake-derived variables included total aboveground N uptake (TNU, grain N uptake (GNU, N recovery efficiency (NRE, net N balance (NNB in relation to GNU [NNB(GNU] and TNU [NNB(TNU], and surplus N (SN. The relationship between N2O and N application rate was sigmoidal with relatively small emissions for N rates <130 kg ha−1, and a sharp increase for N rates from 130 to 220 kg ha−1; on average, N2O increased linearly by about 5 g N per kg of N applied for rates up to 220 kg ha−1. Fairly strong and significant negative relationships existed between N2O and NRE when management focused on N application rate (r2 = 0.52 or rate and timing combinations (r2 = 0.65. For every percentage point increase, N2O decreased by 13 g N ha−1 in response to N rates, and by 20 g N ha−1 for NRE changes in response to rate-by-timing treatments. However, more consistent positive relationships (R2 = 0.73–0.77 existed between N2O and NNB(TNU, NNB(GNU, and SN, regardless of rate and timing of N application; on average N2O emission increased by about 5, 7, and 8 g N, respectively, per kg increase of NNB(GNU, NNB(TNU, and SN. Neither N source nor placement influenced the relationship between N2O and NRE. Overall, our analysis indicated that a careful selection of appropriate N rate applied at the right time can both increase NRE and reduce N

  11. Nitrogen oxides emission of mobile equipment in the port of Rotterdam. Consequences for nitrogen dioxide concentration, nitrogen deposition and a deduction of emission factors for container and bulk businesses; Stikstofoxidenemissies van mobiele werktuigen in de Rotterdamse haven. Gevolgen voor stikstofdioxide concentratie, stikstofdepositie, en een afleiding van emissiefactoren voor container- en droge bulk bedrijven

    Energy Technology Data Exchange (ETDEWEB)

    Okkerse, W J.H.; De Gier, C W

    2011-08-15

    In container terminals, dry bulk businesses and construction sites in the port of Rotterdam, the Netherlands, large masses of goods are transported by means of diesel-fuelled equipment every year. The combustion of diesel in this equipment results in emissions of nitrogen oxides (NOx) and particulate matter. This study has calculated the amounts of NOx emissions of the involved businesses based on detailed data on the composition of the equipment fleet of six representative storage and transshipment businesses. The resulting contribution to nitrogen oxide concentration at ground level and the nitrogen deposition have been calculated with the OPS model (Operational Priority Substances) [Dutch] Bij containerterminals, droge bulk bedrijven en bouwplaatsen in de Rotterdamse haven wordt jaarlijks een grote massa aan goederen getransporteerd met behulp van dieselaangedreven apparatuur. De verbranding van diesel in deze apparatuur zorgt voor de emissie van stikstofoxiden (NOx) en stof. In dit onderzoek zijn de NOx emissies van de betrokken bedrijven berekend op basis van gedetailleerde gegevens over de samenstelling van het werktuigenpark van zes representatieve op- en overslagbedrijven. De resulterende bijdrage aan de stikstofdioxide (NO2) concentratie op leefniveau en de stikstofdepositie is berekend met het OPS-model (Operationele Prioritaire Stoffen)

  12. Selective fluorescence quenching of nitrogen-containing polycyclic aromatic hydrocarbons by aliphatic amines

    International Nuclear Information System (INIS)

    Li Xiaoping; McGuffin, Victoria L.

    2004-01-01

    In this investigation, primary, secondary, and tertiary amines are evaluated for their efficiency and selectivity as fluorescence quenchers for polycyclic aromatic hydrocarbons (PAHs) and nitrogen-containing polycyclic aromatic hydrocarbons (N-PAHs). In general, the quenching efficiency tends to increase from primary to tertiary amine due to a greater number of alkyl groups that increase the electron-donating ability. However, the selectivity decreases from primary to tertiary amine. The effect of low concentrations of water is also examined. Because water can form hydrogen bonds with amines, the nonbonding electron pair is not available for interaction with the fluorophore, thus the quenching constant is decreased. These aliphatic amines are then applied to PAHs and N-PAHs and some interesting trends are observed. Whereas amino-PAHs remain virtually unquenched by different amines, aza-PAHs are all quenched well. The selectivity between aza-PAHs and amino-PAHs is as high as several hundred. This trend provides an easy and effective method to discriminate between these classes of N-PAHs. Moreover, the alternant aza-PAHs are quenched more than their corresponding alternant PAHs

  13. Highly selective and sensitive fluorescence detection of Zn(2+) and Cd(2+) ions by using an acridine sensor.

    Science.gov (United States)

    Visscher, A; Bachmann, S; Schnegelsberg, C; Teuteberg, T; Mata, R A; Stalke, D

    2016-04-07

    Fluorescence spectroscopy investigations of the new acridine derivative bis(N,N-dimethylaminemethylene)acridine (3) show remarkable selectivity and sensitivity towards Zn(2+) and Cd(2+) ions in methanol and for the latter even in water. Through the chelation of the metal ions the present PET effect is quenched, significantly enhancing the emission intensity of the fluorophore. In solution, the bonding situation is studied by fluorescence and NMR spectroscopy, as well as ESI-TOF mass-spectrometry measurements. The solid state environment is investigated by X-ray diffraction and computational calculations. Here, we can show the complexation of the zinc and cadmium ions by the methylene bridged amine receptors as well as by the nitrogen atom of the acridine system.

  14. Factors controlling regional differences in forest soil emission of nitrogen oxides (NO and N2O

    Directory of Open Access Journals (Sweden)

    K. Pilegaard

    2006-01-01

    Full Text Available Soil emissions of NO and N2O were measured continuously at high frequency for more than one year at 15 European forest sites as part of the EU-funded project NOFRETETE. The locations represent different forest types (coniferous/deciduous and different nitrogen loads. Geographically they range from Finland in the north to Italy in the south and from Hungary in the east to Scotland in the west. The highest NO emissions were observed from coniferous forests, whereas the lowest NO emissions were observed from deciduous forests. The NO emissions from coniferous forests were highly correlated with N-deposition. The site with the highest average annual emission (82 μg NO-N m−2 h−1 was a spruce forest in South-Germany (Höglwald receiving an annual N-deposition of 2.9 g m−2. NO emissions close to the detection limit were observed from a pine forest in Finland where the N-deposition was 0.2 g N m−2 a−1. No significant correlation between N2O emission and N-deposition was found. The highest average annual N2O emission (20 μg N2O-N m−2 h−1 was found in an oak forest in the Mátra mountains (Hungary receiving an annual N-deposition of 1.6 g m−2. N2O emission was significantly negatively correlated with the C/N ratio. The difference in N-oxide emissions from soils of coniferous and deciduous forests may partly be explained by differences in N-deposition rates and partly by differences in characteristics of the litter layer and soil. NO was mainly derived from nitrification whereas N2O was mainly derived from denitrification. In general, soil moisture is lower at coniferous sites (at least during spring time and the litter layer of coniferous forests is thick and well aerated favouring nitrification and thus release of NO. Conversely, the higher rates of denitrification in deciduous forests due to a compact and moist litter layer lead to N2O production and NO consumption in the soil. The two factors soil moisture and soil temperature are

  15. Enhanced nitrogen deposition over China

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xuejun; Zhang, Ying; Han, Wenxuan; Tang, Aohan; Shen, Jianlin; Cui, Zhenling; Christie, Peter; Zhang, Fusuo [College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193 (China); Vitousek, Peter [Department of Biology, Stanford University, Stanford, California 94305 (United States); Erisman, Jan Willem [VU University Amsterdam, 1081 HV Amsterdam (Netherlands); Goulding, Keith [The Sustainable Soils and Grassland Systems Department, Rothamsted Research, Harpenden AL5 2JQ (United Kingdom); Fangmeier, Andreas [Institute of Landscape and Plant Ecology, University of Hohenheim, 70593 Stuttgart (Germany)

    2013-02-28

    China is experiencing intense air pollution caused in large part by anthropogenic emissions of reactive nitrogen. These emissions result in the deposition of atmospheric nitrogen (N) in terrestrial and aquatic ecosystems, with implications for human and ecosystem health, greenhouse gas balances and biological diversity. However, information on the magnitude and environmental impact of N deposition in China is limited. Here we use nationwide data sets on bulk N deposition, plant foliar N and crop N uptake (from long-term unfertilized soils) to evaluate N deposition dynamics and their effect on ecosystems across China between 1980 and 2010. We find that the average annual bulk deposition of N increased by approximately 8 kilograms of nitrogen per hectare (P < 0.001) between the 1980s (13.2 kilograms of nitrogen per hectare) and the 2000s (21.1 kilograms of nitrogen per hectare). Nitrogen deposition rates in the industrialized and agriculturally intensified regions of China are as high as the peak levels of deposition in northwestern Europe in the 1980s, before the introduction of mitigation measures. Nitrogen from ammonium (NH4+) is the dominant form of N in bulk deposition, but the rate of increase is largest for deposition of N from nitrate (NO3-), in agreement with decreased ratios of NH3 to NOx emissions since 1980. We also find that the impact of N deposition on Chinese ecosystems includes significantly increased plant foliar N concentrations in natural and semi-natural (that is, non-agricultural) ecosystems and increased crop N uptake from long-term-unfertilized croplands. China and other economies are facing a continuing challenge to reduce emissions of reactive nitrogen, N deposition and their negative effects on human health and the environment.

  16. Color optimization of single emissive white OLEDs via energy transfer between RGB fluorescent dopants

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Nam Ho; Kim, You-Hyun; Yoon, Ju-An; Lee, Sang Youn [Department of Green Energy and Semiconductor Engineering, Hoseo University, Asan (Korea, Republic of); Ryu, Dae Hyun [Department of Information Technology, Hansei University, Gunpo (Korea, Republic of); Wood, Richard [Department of Engineering Physics, McMaster University, Hamilton, Ontario, Canada L8S 4L7 (Canada); Moon, C.-B. [Department of Green Energy and Semiconductor Engineering, Hoseo University, Asan (Korea, Republic of); Kim, Woo Young, E-mail: wykim@hoseo.edu [Department of Green Energy and Semiconductor Engineering, Hoseo University, Asan (Korea, Republic of); Department of Engineering Physics, McMaster University, Hamilton, Ontario, Canada L8S 4L7 (Canada)

    2013-11-15

    The electroluminescent characteristics of white organic light-emitting diodes (WOLEDs) were investigated including single emitting layer (SEL) with an ADN host and dopants; BCzVBi, C545T, and DCJTB for blue, green and red emission, respectively. The structure of the high efficiency WOLED device was; ITO/NPB(700 Å)/ADN: BCzVBi-7%:C545T-0.05%:DCJTB-0.1%(300 Å)/Bphen(300 Å)/Liq(20 Å)/Al(1200 Å) for mixing three primary colors. Luminous efficiency was 9.08 cd/A at 3.5 V and Commission Intenationale de L’eclairage (CIE{sub x,y}) coordinates of white emission was measured as (0.320, 0.338) at 8 V while simulated CIE{sub x,y} coordinates were (0.336, 0.324) via estimation from each dopant's PL spectrum. -- Highlights: • This paper observes single-emissive-layered white OLED using fluorescent dopants. • Electrical and optical properties are analyzed. • Color stability of white OLED is confirmed for new planar light source.

  17. Color optimization of single emissive white OLEDs via energy transfer between RGB fluorescent dopants

    International Nuclear Information System (INIS)

    Kim, Nam Ho; Kim, You-Hyun; Yoon, Ju-An; Lee, Sang Youn; Ryu, Dae Hyun; Wood, Richard; Moon, C.-B.; Kim, Woo Young

    2013-01-01

    The electroluminescent characteristics of white organic light-emitting diodes (WOLEDs) were investigated including single emitting layer (SEL) with an ADN host and dopants; BCzVBi, C545T, and DCJTB for blue, green and red emission, respectively. The structure of the high efficiency WOLED device was; ITO/NPB(700 Å)/ADN: BCzVBi-7%:C545T-0.05%:DCJTB-0.1%(300 Å)/Bphen(300 Å)/Liq(20 Å)/Al(1200 Å) for mixing three primary colors. Luminous efficiency was 9.08 cd/A at 3.5 V and Commission Intenationale de L’eclairage (CIE x,y ) coordinates of white emission was measured as (0.320, 0.338) at 8 V while simulated CIE x,y coordinates were (0.336, 0.324) via estimation from each dopant's PL spectrum. -- Highlights: • This paper observes single-emissive-layered white OLED using fluorescent dopants. • Electrical and optical properties are analyzed. • Color stability of white OLED is confirmed for new planar light source

  18. 40 CFR Table 1 to Subpart Kkkk of... - Nitrogen Oxide Emission Limits for New Stationary Combustion Turbines

    Science.gov (United States)

    2010-07-01

    ... Stationary Combustion Turbines 1 Table 1 to Subpart KKKK of Part 60 Protection of Environment ENVIRONMENTAL... Standards of Performance for Stationary Combustion Turbines Pt. 60, Subpt. KKKK, Table 1 Table 1 to Subpart KKKK of Part 60—Nitrogen Oxide Emission Limits for New Stationary Combustion Turbines Combustion...

  19. Laser induced aluminiun plasma analysis by optical emission spectroscopy in a nitrogen background gas

    International Nuclear Information System (INIS)

    Chamorro, J C; Uzuriaga, J; Riascos, H

    2012-01-01

    We studied an Al plasma generated by a Nd:YAG laser with a laser fluence of 4 J/cm 2 , a wavelength of 1064 nm, energy pulse of 500 mJ and 10 Hz repetition rate. We studied their spectral characteristics at various ambient nitrogen pressures by optical emission spectroscopy (OES). The N 2 gas pressure was varied from 20 mTorr to 150 mTorr. In Al plume, both atomic and ionic spectra were observed. The electron temperature and electron number density of the plume as of the function ambient gas pressure were determined. The electron temperature was calculated by using the Boltzmann-plot method and the number density was calculated considering the stark effect as dominating on the emission lines.

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

    Directory of Open Access Journals (Sweden)

    Taylor Lima de Souza

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

  1. Reducing emission of nitrogen oxides during combustion of black coal from the Kuzbass

    Energy Technology Data Exchange (ETDEWEB)

    Kotler, V.R.; Lobov, G.V.; Gedike, I.A.

    1983-02-01

    Black coal from the Kuzbass used as fuel by the ZapSibTEhTs fossil-fuel power plant is rich in nitrogen: nitrogen content ranges from 2.8% to 3.5%. Under these conditions conventional methods of combustion cause air pollution exceeding permissible levels. A method for combustion of coal dust in stages has been successfully tested at the plant: some of the burners located in the top zone of the furnace (the BKZ-210-140F boiler) are used for air supply. From 16% to 18% of air supplied to the furnace is directed to the upper burners. Use of this system (called tertiary air supply as opposed to the secondary air system) reduced nitrogen oxide emission by 1.5 times (from 0.87 to 0.57 g/m/sup 3/). Position of nozzles used for tertiary air supply in relation to the burners used for supply of coal dust in the tangential shaped furnace is shown in a scheme. The optimum position of tertiary air supply system in relation to burners taking into account corrosion hazards as well as the hazards of reducing combustion efficiency is discussed. Recommendation on furnace design and burner position which prevent efficiency decrease and corrosion hazards are made.

  2. Monitoring i-motif transitions through the exciplex emission of a fluorescent probe incorporating two (Py)A units.

    Science.gov (United States)

    Lee, Il Joon; Kim, Byeang Hyean

    2012-02-18

    Pairs of pyrene-modified deoxyadenosine ((Py)A) units induce a stable interstrand i-motif structure, which can be characterized by a change in the fluorescence λ(max), with an exciplex emission that is not observable in its single-strand structure. This journal is © The Royal Society of Chemistry 2012

  3. Variations in the 6.2 μm emission profile in starburst-dominated galaxies: a signature of polycyclic aromatic nitrogen heterocycles (PANHs)?

    Science.gov (United States)

    Canelo, Carla M.; Friaça, Amâncio C. S.; Sales, Dinalva A.; Pastoriza, Miriani G.; Ruschel-Dutra, Daniel

    2018-04-01

    Analyses of the polycyclic aromatic hydrocarbon (PAH) feature profiles, especially the 6.2 μm feature, could indicate the presence of nitrogen incorporated in their aromatic rings. In this work, 155 predominantly starburst-dominated galaxies (including H II regions and Seyferts, for example), extracted from the Spitzer/Infrared Spectrograph ATLAS project, have their 6.2 μm profiles fitted allowing their separation into the Peeters' A, B, and C classes. 67 per cent of these galaxies were classified as class A, 31 per cent were as class B, and 2 per cent as class C. Currently, class A sources, corresponding to a central wavelength near 6.22 μm, seem only to be explained by polycyclic aromatic nitrogen heterocycles (PANHs), whereas class B may represent a mix between PAHs and PANHs emissions or different PANH structures or ionization states. Therefore, these spectra suggest a significant presence of PANHs in the interstellar medium (ISM) of these galaxies that could be related to their starburst-dominated emission. These results also suggest that PANHs constitute another reservoir of nitrogen in the Universe, in addition to the nitrogen in the gas phase and ices of the ISM.

  4. Effects of contrasting catch crops on nitrogen availability and nitrous oxide emissions in an organic cropping system

    DEFF Research Database (Denmark)

    Li, Xiaoxi; Petersen, Søren O; Sørensen, Peter

    2015-01-01

    Legume-based catch crops (LBCCs) may act as an important source of nitrogen (N) in organic crop rotations because of biological N fixation. However, the potential risk of high nitrous oxide (N2O) emissions needs to be taken into account when including LBCCs in crop rotations. Here, we report...

  5. Effects of nitrogen fertilisation rate and maturity of grass silage on methane emission by lactating dairy cows

    NARCIS (Netherlands)

    Warner, D.; Hatew, B.; Podesta, S.C.; Klop, G.; Gastelen, van S.; Laar, van H.; Dijkstra, J.; Bannink, A.

    2016-01-01

    Grass silage is typically fed to dairy cows in temperate regions. However, in vivo information on methane (CH4) emission from grass silage of varying quality is limited. We evaluated the effect of two rates of nitrogen (N) fertilisation of grassland (low fertilisation (LF), 65 kg of N/ha; and high

  6. Electronic structure and field emission properties of nitrogen doped graphene nano-flakes (GNFs:N) and carbon nanotubes (CNTs:N)

    Energy Technology Data Exchange (ETDEWEB)

    Ray, Sekhar C., E-mail: Raysc@unisa.ac.za [Department of Physics, College of Science, Engineering and Technology, University of South Africa, Private Bag X6, Florida, 1710, Science Campus, Christiaan de Wet and Pioneer Avenue, Florida Park, Johannesburg (South Africa); Pong, W.F. [Department of Physics, Tamkang University, Tamsui 251, New Taipei City, Taiwan (China); Papakonstantinou, P. [Nanotechnology and Integrated Bio-Engineering Centre, University of Ulster, Shore Road, Newtownabbey BT37 0QB (United Kingdom)

    2016-09-01

    Highlights: • Nitrogen doped graphene nano-flakes (GNFs:N) and carbon nano-tubes (CNTs:N) are used to study the electronic/bonding structure along with their defects state. • The I{sub D}/I{sub G} ratio obtained from Raman spectroscopy used for the study of the defects states of CNTs:N than GNFs:N. • The electron field emission result shows that the turn on electric field is lower in case of CNTs:N than GNFs:N. • All results are good agreement with XANES and the results obtained from Raman spectra. - Abstract: Substitution of hetero-atom doping is a promising route to modulate the outstanding material properties of carbon nanotubes and graphene for customized applications. Nitrogen-doping has been introduced to ensure tunable work-function, enhanced n-type carrier concentration, diminished surface energy, and manageable polarization. Along with the promising assessment of N-doping effects, research on the N-doped carbon based composite structures is emerging for the synergistic integration with various functional materials. Nitrogen undoped/doped graphene nano-flakes (GNFs/GNFs:N) and multiwall carbon nano-tubes (MWCNTs/MWCNTs:N) are used for comparative study of their electronic/bonding structure along with their defects state. X-ray absorption near edge structure (XANES) spectroscopy shows that the GNFs:N produce mainly pyridine like structure; whereas MWCNTs:N shows graphitic nitrogen atoms are attached with the carbon lattice. The I{sub D}/I{sub G} ratio obtained from Raman spectroscopy shows that the defects is higher in MWCNTs:N than GNFs:N. The electron field emission result shows that the turn on electric field is lower (higher electron emission current) in case of MWCNTs:N than GNFs:N and are good agreement with XANES and the results obtained from Raman spectra.

  7. Preparation, one- and two-photon properties of carbazole derivatives containing nitrogen heterocyclic ring

    Science.gov (United States)

    Zhang, Yichi; Wang, Ping; Li, Liang; Chen, Zhimin; He, Chunying; Wu, Yiqun

    Preparation of recording materials with high two-photon absorption activities is one of the important issues to superhigh- density two-photon absorption (TPA) three-dimensional (3D) optical data storage. In this paper, three new carbazole derivatives containing nitrogen heterocyclic ring with symmetric and asymmetric structures are prepared using ethylene as the π bridge between the carbazole unit and nitrogen heterocyclic ring, namely, 9-butyl-3-(2-(1,8- naphthyridin)vinyl)-carbazole (material 1), 9-butyl-3,6-bis(2-(1,8-naphthyl)vinyl)-carbazole (material 2) and 9-butyl-3,6- bis(2-(quinolin)vinyl)-carbazole (material 3). Their one photon properties including linear absorption spectra, fluorescence emission spectra, and fluorescence quantum yields are studied. The fluorescence excited by 120 fs pulse at 800 nm Ti: sapphire laser operating at 1 kHz repetition rate with different incident powers of 9-butyl-3-(2-(quinolin) vinyl)-carbazole (material 3) was investigated, and two-photon absorption cross-sections has been obtained. It is shown that material 3 containing quinoline rings as electron acceptor with symmetric structure exhibit high two-photon absorption activity. The result implies that material 3 (9-butyl-3-(2-(quinolin) vinyl)-carbazole) is a good candidate as a promising recording material for super-high-density two-photon absorption (TPA) three-dimensional (3D) optical data storage. The influence of chemical structure of the materials on the optical properties is discussed.

  8. The structure of mAG, a monomeric mutant of the green fluorescent protein Azami-Green, reveals the structural basis of its stable green emission

    International Nuclear Information System (INIS)

    Ebisawa, Tatsuki; Yamamura, Akihiro; Kameda, Yasuhiro; Hayakawa, Kou; Nagata, Koji; Tanokura, Masaru

    2010-01-01

    The crystal structure of a monomeric mutant of Azami-Green (mAG) from G. fascicularis was determined at 2.2 Å resolution. Monomeric Azami-Green (mAG) from the stony coral Galaxea fascicularis is the first known monomeric green-emitting fluorescent protein that is not a variant of Aequorea victoria green fluorescent protein (avGFP). These two green fluorescent proteins are only 27% identical in their amino-acid sequences. mAG is more similar in its amino-acid sequence to four fluorescent proteins: Dendra2 (a green-to-red irreversibly photoconverting fluorescent protein), Dronpa (a bright-and-dark reversibly photoswitchable fluorescent protein), KikG (a tetrameric green-emitting fluorescent protein) and Kaede (another green-to-red irreversibly photoconverting fluorescent protein). To reveal the structural basis of stable green emission by mAG, the 2.2 Å crystal structure of mAG has been determined and compared with the crystal structures of avGFP, Dronpa, Dendra2, Kaede and KikG. The structural comparison revealed that the chromophore formed by Gln62-Tyr63-Gly64 (QYG) and the fixing of the conformation of the imidazole ring of His193 by hydrogen bonds and van der Waals contacts involving His193, Arg66 and Thr69 are likely to be required for the stable green emission of mAG. The crystal structure of mAG will contribute to the design and development of new monomeric fluorescent proteins with faster maturation, brighter fluorescence, improved photostability, new colours and other preferable properties as alternatives to avGFP and its variants

  9. Nitrous oxide emissions from yellow brown soil as affected by incorporation of crop residues with different carbon-to-nitrogen ratios: a case study in central China.

    Science.gov (United States)

    Lin, Shan; Iqbal, Javed; Hu, Ronggui; Shaaban, Muhammad; Cai, Jianbo; Chen, Xi

    2013-08-01

    To investigate the influence of crop residues decomposition on nitrous oxide (N2O) emission, a field study was performed with application of crop residues with different C:N ratios in a bare yellow brown soil at the experimental station of Zhangjiachong at Zigui, China. We set up six experimental treatments: no crop residue (CK), rapeseed cake (RC), potato stalk (PS), rice straw (RS), wheat straw (WS), and corn straw (CS). The carbon (C) to nitrogen (N) ratios of these crop residues were 7.5, 32.9, 40.4, 65.7, and 90.9, respectively. Nitrous oxide fluxes were measured using a static closed chamber method. N2O emissions were significantly enhanced by incorporation of crop residues. Cumulative N2O emissions negatively correlated with C:N ratio (R (2) = 0.9821) of the crop residue, but they were positively correlated with average concentrations of dissolved organic carbon and microbial biomass carbon. Nitrogen emission fraction, calculated as N2O-N emissions originated from the crop residues N, positively correlated with C:N ratio of the residues (P emissions because a significant correlation (P emissions in all treatments except the control. In contrast, a significant relationship between soil moisture and N2O emissions was found in the control only. Furthermore, N2O emission significantly correlated (P carbon and nitrogen contents can significantly alter soil N2O flux rates; and (2) soil biotic as well as abiotic variables are critical in determining soil-atmospheric N2O emissions after crop residue incorporation into soil.

  10. Multimodal fluorescence imaging spectroscopy

    NARCIS (Netherlands)

    Stopel, Martijn H W; Blum, Christian; Subramaniam, Vinod; Engelborghs, Yves; Visser, Anthonie J.W.G.

    2014-01-01

    Multimodal fluorescence imaging is a versatile method that has a wide application range from biological studies to materials science. Typical observables in multimodal fluorescence imaging are intensity, lifetime, excitation, and emission spectra which are recorded at chosen locations at the sample.

  11. A Dual Reporter Iodinated Labeling Reagent for Cancer Positron Emission Tomography Imaging and Fluorescence-Guided Surgery

    Science.gov (United States)

    2018-01-01

    The combination of early diagnosis and complete surgical resection offers the greatest prospect of curative cancer treatment. An iodine-124/fluorescein-based dual-modality labeling reagent, 124I-Green, constitutes a generic tool for one-step installation of a positron emission tomography (PET) and a fluorescent reporter to any cancer-specific antibody. The resulting antibody conjugate would allow both cancer PET imaging and intraoperative fluorescence-guided surgery. 124I-Green was synthesized in excellent radiochemical yields of 92 ± 5% (n = 4) determined by HPLC with an improved one-pot three-component radioiodination reaction. The A5B7 carcinoembryonic antigen (CEA)-specific antibody was conjugated to 124I-Green. High tumor uptake of the dual-labeled A5B7 of 20.21 ± 2.70, 13.31 ± 0.73, and 10.64 ± 1.86%ID/g was observed in CEA-expressing SW1222 xenograft mouse model (n = 3) at 24, 48, and 72 h post intravenous injection, respectively. The xenografts were clearly visualized by both PET/CT and ex vivo fluorescence imaging. These encouraging results warrant the further translational development of 124I-Green for cancer PET imaging and fluorescence-guided surgery. PMID:29388770

  12. Spectral Neugebauer-based color halftone prediction model accounting for paper fluorescence.

    Science.gov (United States)

    Hersch, Roger David

    2014-08-20

    We present a spectral model for predicting the fluorescent emission and the total reflectance of color halftones printed on optically brightened paper. By relying on extended Neugebauer models, the proposed model accounts for the attenuation by the ink halftones of both the incident exciting light in the UV wavelength range and the emerging fluorescent emission in the visible wavelength range. The total reflectance is predicted by adding the predicted fluorescent emission relative to the incident light and the pure reflectance predicted with an ink-spreading enhanced Yule-Nielsen modified Neugebauer reflectance prediction model. The predicted fluorescent emission spectrum as a function of the amounts of cyan, magenta, and yellow inks is very accurate. It can be useful to paper and ink manufacturers who would like to study in detail the contribution of the fluorescent brighteners and the attenuation of the fluorescent emission by ink halftones.

  13. Recent developments in multimodality fluorescence imaging probes

    Directory of Open Access Journals (Sweden)

    Jianhong Zhao

    2018-05-01

    Full Text Available Multimodality optical imaging probes have emerged as powerful tools that improve detection sensitivity and accuracy, important in disease diagnosis and treatment. In this review, we focus on recent developments of optical fluorescence imaging (OFI probe integration with other imaging modalities such as X-ray computed tomography (CT, magnetic resonance imaging (MRI, positron emission tomography (PET, single-photon emission computed tomography (SPECT, and photoacoustic imaging (PAI. The imaging technologies are briefly described in order to introduce the strengths and limitations of each techniques and the need for further multimodality optical imaging probe development. The emphasis of this account is placed on how design strategies are currently implemented to afford physicochemically and biologically compatible multimodality optical fluorescence imaging probes. We also present studies that overcame intrinsic disadvantages of each imaging technique by multimodality approach with improved detection sensitivity and accuracy. KEY WORDS: Optical imaging, Fluorescence, Multimodality, Near-infrared fluorescence, Nanoprobe, Computed tomography, Magnetic resonance imaging, Positron emission tomography, Single-photon emission computed tomography, Photoacoustic imaging

  14. Nitrogen nutrition in cotton and control strategies for greenhouse gas emissions: a review.

    Science.gov (United States)

    Khan, Aziz; Tan, Daniel Kean Yuen; Munsif, Fazal; Afridi, Muhammad Zahir; Shah, Farooq; Wei, Fan; Fahad, Shah; Zhou, Ruiyang

    2017-10-01

    Cotton (Gossypium hirustum L.) is grown globally as a major source of natural fiber. Nitrogen (N) management is cumbersome in cotton production systems; it has more impacts on yield, maturity, and lint quality of a cotton crop than other primary plant nutrient. Application and production of N fertilizers consume large amounts of energy, and excess application can cause environmental concerns, i.e., nitrate in ground water, and the production of nitrous oxide a highly potent greenhouse gas (GHG) to the atmosphere, which is a global concern. Therefore, improving nitrogen use efficiency (NUE) of cotton plant is critical in this context. Slow-release fertilizers (e.g., polymer-coated urea) have the potential to increase cotton yield and reduce environmental pollution due to more efficient use of nutrients. Limited literature is available on the mitigation of GHG emissions for cotton production. Therefore, this review focuses on the role of N fertilization, in cotton growth and GHG emission management strategies, and will assess, justify, and organize the researchable priorities. Nitrate and ammonium nitrogen are essential nutrients for successful crop production. Ammonia (NH 3 ) is a central intermediate in plant N metabolism. NH 3 is assimilated in cotton by the mediation of glutamine synthetase, glutamine (z-) oxoglutarate amino-transferase enzyme systems in two steps: the first step requires adenosine triphosphate (ATP) to add NH 3 to glutamate to form glutamine (Gln), and the second step transfers the NH 3 from glutamine (Gln) to α-ketoglutarate to form two glutamates. Once NH 3 has been incorporated into glutamate, it can be transferred to other carbon skeletons by various transaminases to form additional amino acids. The glutamate and glutamine formed can rapidly be used for the synthesis of low-molecular-weight organic N compounds (LMWONCs) such as amides, amino acids, ureides, amines, and peptides that are further synthesized into high-molecular-weight organic

  15. Effects of stepwise nitrogen depletion on carotenoid content, fluorescence parameters and the cellular stoichiometry of Chlorella vulgaris

    Science.gov (United States)

    Zhang, Ping; Li, Zhe; Lu, Lunhui; Xiao, Yan; Liu, Jing; Guo, Jinsong; Fang, Fang

    2017-06-01

    Stressful conditions can stimulate the accumulation of carotenoids in some microalgae. To obtain more knowledge of the stress response, we studied the effects of different N concentrations on unicellular content of carotenoids using Raman spectroscopic technique; cellular stoichiometric changes and the fluorescence parameters of Chlorella vulgaris were concomitantly studied. Initially, we optimized the Raman scattering conditions and demonstrated the feasibility of unicellular carotenoid analysis by Raman spectroscopic technique. The results showed that an integration time of 10 s, laser power at 0.1 mW and an accumulation time of 1 were the optimum conditions, and the peak height at 1523 cm- 1 scaled linearly with the carotenoid content in the range of 0.625-1440 mg/L with a recovery rate of 97% 103%. In the experiment, seven different nitrogen levels ranging from 0 to 2.48 × 105 μg/L were imposed. Samples were taken at the start, exponential phase and end of the experiment. The results showed that nitrogen stress can facilitate the synthesis of carotenoids, while at the same time, excessive nitrogen stress led to lower proliferative and photosynthetic activity. Compared with carotenoids, chlorophylls were more sensitive to nitrogen stress; it declined dramatically as stress processed. There existed no significant differences for Fv/Fm among different nitrogen levels during the exponential phase, while in the end, it declined and a significant difference appeared between cells in 2.48 × 105 μg/L N and other experimental levels. Photosynthetic efficiency, namely the C/N mole ratio in algal cells, didnot significantly change during the exponential phase; however, apparent increases ultimately occurred, except for the stable C/N in BG11 medium. This increase matched well with the carotenoid decline, indicating that an increasing cellular C/N mole ratio can be used as an indicator of excessive stress in carotenoid production. Besides, there also existed an inverse

  16. Emission inventory; Inventaire des emissions

    Energy Technology Data Exchange (ETDEWEB)

    Fontelle, J.P. [CITEPA, Centre Interprofessionnel Technique d`Etudes de la Pollution Atmospherique, 75 - Paris (France)

    1997-12-31

    Statistics on air pollutant (sulfur dioxide, nitrogen oxides and ammonium) emissions, acid equivalent emissions and their evolution since 1990 in the various countries of Europe and the USA, are presented. Emission data from the industrial, agricultural, transportation and power sectors are given, and comparisons are carried out between countries based on Gnp and population, pollution import/export fluxes and compliance to the previous emission reduction objectives

  17. Single excitation-emission fluorescence spectrum (EEF) for determination of cetane improver in diesel fuel.

    Science.gov (United States)

    Insausti, Matías; Fernández Band, Beatriz S

    2015-04-05

    A highly sensitive spectrofluorimetric method has been developed for the determination of 2-ethylhexyl nitrate in diesel fuel. Usually, this compound is used as an additive in order to improve cetane number. The analytical method consists in building the chemometric model as a first step. Then, it is possible to quantify the analyte with only recording a single excitation-emission fluorescence spectrum (EEF), whose data are introduced in the chemometric model above mentioned. Another important characteristic of this method is that the fuel sample was used without any pre-treatment for EEF. This work provides an interest improvement to fluorescence techniques using the rapid and easily applicable EEF approach to analyze such complex matrices. Exploding EEF was the key to a successful determination, obtaining a detection limit of 0.00434% (v/v) and a limit of quantification of 0.01446% (v/v). Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Comparison of greenhouse gas emissions from rice paddy fields under different nitrogen fertilization loads in Chongming Island, Eastern China

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xianxian [School of Agriculture and Biology, Shanghai Jiao Tong University, Dongchuan Rd. 800, Shanghai 200240 (China); Research Centre for Low Carbon Agriculture, Shanghai Jiao Tong University, Dongchuan Rd. 800, Shanghai 200240 (China); Key Laboratory for Urban Agriculture (South), Ministry of Agriculture, PR China, Dongchuan Rd. 800, Shanghai 200240 (China); Yin, Shan, E-mail: yinshan@sjtu.edu.cn [School of Agriculture and Biology, Shanghai Jiao Tong University, Dongchuan Rd. 800, Shanghai 200240 (China); Research Centre for Low Carbon Agriculture, Shanghai Jiao Tong University, Dongchuan Rd. 800, Shanghai 200240 (China); Key Laboratory for Urban Agriculture (South), Ministry of Agriculture, PR China, Dongchuan Rd. 800, Shanghai 200240 (China); Li, Yinsheng [School of Agriculture and Biology, Shanghai Jiao Tong University, Dongchuan Rd. 800, Shanghai 200240 (China); Research Centre for Low Carbon Agriculture, Shanghai Jiao Tong University, Dongchuan Rd. 800, Shanghai 200240 (China); Zhuang, Honglei [School of Agriculture and Biology, Shanghai Jiao Tong University, Dongchuan Rd. 800, Shanghai 200240 (China); Research Centre for Low Carbon Agriculture, Shanghai Jiao Tong University, Dongchuan Rd. 800, Shanghai 200240 (China); Key Laboratory for Urban Agriculture (South), Ministry of Agriculture, PR China, Dongchuan Rd. 800, Shanghai 200240 (China); Li, Changsheng [School of Agriculture and Biology, Shanghai Jiao Tong University, Dongchuan Rd. 800, Shanghai 200240 (China); Research Centre for Low Carbon Agriculture, Shanghai Jiao Tong University, Dongchuan Rd. 800, Shanghai 200240 (China); Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, Morse Hall, College Road, NH 03824-3525 (United States); and others

    2014-02-01

    Rice is one of the major crops of southern China and Southeast Asia. Rice paddies are one of the largest agricultural greenhouse gas (GHG) sources in this region because of the application of large quantities of nitrogen (N) fertilizers to the plants. In particular, the production of methane (CH{sub 4}) is a concern. Investigating a reasonable amount of fertilizers to apply to plants is essential to maintaining high yields while reducing GHG emissions. In this study, three levels of fertilizer application [high (300 kg N/ha), moderate (210 kg N/ha), and low (150 kg N/ha)] were designed to examine the effects of variation in N fertilizer application rate on carbon dioxide (CO{sub 2}), methane (CH{sub 4}), and nitrous oxide (N{sub 2}O) emissions from the paddy fields in Chongming Island, Shanghai, China. The high level (300 kg N/ha) represented the typical practice adopted by the local farmers in the area. Maximum amounts of CH{sub 4} and N{sub 2}O fluxes were observed upon high-level fertilizer application in the plots. Cumulative N{sub 2}O emissions of 23.09, 40.10, and 71.08 mg N{sub 2}O/m{sup 2} were observed over the growing season in 2011 under the low-, moderate-, and high-level applications plots, respectively. The field data also indicated that soil temperatures at 5 and 10 cm soil depths significantly affected soil respiration; the relationship between Rs and soil temperature in this study could be described by an exponential model. Our study showed that reducing the high rate of fertilizer application is a feasible way of attenuating the global-warming potential while maintaining the optimum yield for the studied paddy fields. - Highlights: • In Chongming Island, Shanghai, GHG emissions were measured under different nitrogen fertilizer rates from the paddy. • Low nitrogen fertilizer application reduced CH{sub 4} and N{sub 2}O emissions. • The study showed that 210 kg N/ha was the suitable fertilizer application rate.

  19. Comparison of greenhouse gas emissions from rice paddy fields under different nitrogen fertilization loads in Chongming Island, Eastern China

    International Nuclear Information System (INIS)

    Zhang, Xianxian; Yin, Shan; Li, Yinsheng; Zhuang, Honglei; Li, Changsheng

    2014-01-01

    Rice is one of the major crops of southern China and Southeast Asia. Rice paddies are one of the largest agricultural greenhouse gas (GHG) sources in this region because of the application of large quantities of nitrogen (N) fertilizers to the plants. In particular, the production of methane (CH 4 ) is a concern. Investigating a reasonable amount of fertilizers to apply to plants is essential to maintaining high yields while reducing GHG emissions. In this study, three levels of fertilizer application [high (300 kg N/ha), moderate (210 kg N/ha), and low (150 kg N/ha)] were designed to examine the effects of variation in N fertilizer application rate on carbon dioxide (CO 2 ), methane (CH 4 ), and nitrous oxide (N 2 O) emissions from the paddy fields in Chongming Island, Shanghai, China. The high level (300 kg N/ha) represented the typical practice adopted by the local farmers in the area. Maximum amounts of CH 4 and N 2 O fluxes were observed upon high-level fertilizer application in the plots. Cumulative N 2 O emissions of 23.09, 40.10, and 71.08 mg N 2 O/m 2 were observed over the growing season in 2011 under the low-, moderate-, and high-level applications plots, respectively. The field data also indicated that soil temperatures at 5 and 10 cm soil depths significantly affected soil respiration; the relationship between Rs and soil temperature in this study could be described by an exponential model. Our study showed that reducing the high rate of fertilizer application is a feasible way of attenuating the global-warming potential while maintaining the optimum yield for the studied paddy fields. - Highlights: • In Chongming Island, Shanghai, GHG emissions were measured under different nitrogen fertilizer rates from the paddy. • Low nitrogen fertilizer application reduced CH 4 and N 2 O emissions. • The study showed that 210 kg N/ha was the suitable fertilizer application rate

  20. Upconverting fluorescent nanoparticles for biodetection and photoactivation

    Science.gov (United States)

    Huang, Kai; Li, WenKai; Jayakumar, Muthu Kumara Gnanasammandhan; Zhang, Yong

    2013-03-01

    Fluorophores including fluorescent dyes/proteins and quantum dots (QDs) are used for fluorescence-based imaging and detection. These are based on `downconversion fluorescence' and have several drawbacks: photobleaching, autofluorescence, short tissue penetration depth and tissue photo-damage. Upconversion fluorescent nanoparticles (UCNs) emit detectable photons of higher energy in the short wavelength range upon irradiation with near-infrared (NIR) light based on a process termed `upconversion'. UCNs show absolute photostability, negligible autofluorescence, high penetration depth and minimum photodamage to biological tissues. Lanthanide doped nanocrystals with nearinfrared NIR-to-NIR and/or NIR-to-VIS and/or NIR-to-UV upconversion fluorescence emission have been synthesized. The nanocrystals with small size and tunable multi-color emission have been developed. The emission can be tuned by doping different upconverting lanthanide ions into the nanocrystals. The nanocrystals with core-shell structure have also been prepared to tune the emission color. The surfaces of these nanocrystals have been modified to render them water dispersible and biocompatible. They can be used for ultrasensitive interference-free biodetection because most biomolecules do not have upconversion properties. UCNs are also useful for light based therapy with enhanced efficiency, for example, photoactivation.

  1. Novel lanthanide pH fluorescent probes based on multiple emissions and its visible-light-sensitized feature

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Jintai [School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Zheng, Yuhui, E-mail: yhzheng78@scnu.edu.cn [School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Wang, Qianming, E-mail: qmwang@scnu.edu.cn [Key Laboratory of Theoretical Chemistry of Environment, Ministry of Education, School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Guangzhou Key Laboratory of Materials for Energy Conversion and Storage, Guangzhou 510006 (China); State Key Laboratory of Chemo/Biosensing and Chemometrics, Hunan University, Changsha 410082 (China); Zeng, Zhi [School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Zhang, Cheng Cheng [Departments of Physiology and Developmental Biology, University of Texas Southwestern Medical Center, Dallas (United States)

    2014-08-11

    Graphical abstract: A new type of Eu(III) ofloxacin complex as the fluorescent pH indicator has been reported. Compared to pure ligand, the complex offers more distinguished color changes (green–red–blue) derived from both lanthanide line emissions and the secondary ionization steps of ofloxacin. - Highlights: • The pH probe offers a very wide working range in water (pH 1–14). • The emission changes have multiple colors. • Long-lived excited state lifetimes of Eu(III) has been used. • Two types of pH sensitive hydrogels were fabricated. - Abstract: A new type of Eu(III) ofloxacin complex as the fluorescent pH indicator has been presented. Compared to pure ligand, the complex offers more distinguished color changes (green–red–blue) derived from both lanthanide line emissions and the secondary ionization steps of ofloxacin. During the concentration dependence experiments, the photoluminescence studies on the complex showed that the excitation of this pH probe can occur at a very long wavelength which extends to visible range (Ex = 427 nm). Furthermore, the functional complex was successfully incorporated into soft networks and two novel luminescent hydrogels (rod and film) were fabricated. The soft materials also exhibited specific responses towards the pH variation. Finally, the onion cell-stain experiments were carried out to further confirm the validity of pH dependence and the results support the idea that the material will be suitable for monitoring biological samples in the future.

  2. Characteristics of the fluorescent substances in the Yodo River system by three-dimensional excitation emission matrix spectroscopy; Sanjigen reiki/keiko kodoho ni yoru yodogawa suikeichu no keiko busshitsu no tokucho

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Y.; Nakaguchi, Y.; Hiraki, K.; Kudo, M.; Kimura, M.; Nagao, S. [Japan Atomic Energy Research Inst., Tokyo (Japan)

    1998-08-01

    Organic substances in the river water in Yodo River system were analyzed by three-dimensional excitation emission matrix spectroscopy. Fluorescent substances were taken as an index of organic substances. The amount of fluorescent substances varied widely depending on the environment of river basin. It is suggested that the fluorescent substances are composed of organic substances which is not directly originated from biological activity. It is suggested that the fluorescent substances were produced by leaching of river bottom sediment. The fluorescent substances in Yodo River system consists of fulvic acid-like substances and protein. The analysis of fluorescent substances in river water by three-dimensional excitation emission matrix spectroscopy can be useful means for estimation of variation and origin of fluorescent substances. For better understanding of features of fluorescent substances in the surface water into which various kinds of substances enter, it is necessary to determine the exact sampling points based on the consideration of different sources and to make a database of peak positions for identification of fluorescent substances from fluorescence intensity peak. 29 refs., 3 figs., 2 tabs.

  3. Impact of energy efficiency and replacement of diesel fuel with natural gas in public transport on reducing emissions of nitrogen oxides

    Energy Technology Data Exchange (ETDEWEB)

    Dimitrovski, Dame; Jovanovski, Antonio [Faculty of Mechanical Engineering, ' Ss. Cyril and Methodius' University, Skopje (Macedonia, The Former Yugoslav Republic of)

    2014-07-01

    This paper analyzes the direct emissions of nitrogen oxides from the public transport (bus) in urban areas in the Republic of Macedonia. As influential factors on which to compare the quantity of these emissions are taken: Penetration of new (energy efficient) technologies in bus transport, the intensity of the bus fleet renewal for public transport and replacement of diesel with natural gas. (Author)

  4. The impact of the Nitrates Directive on nitrogen emissions from agriculture in the EU-27 during 2000-2008.

    Science.gov (United States)

    Velthof, G L; Lesschen, J P; Webb, J; Pietrzak, S; Miatkowski, Z; Pinto, M; Kros, J; Oenema, O

    2014-01-15

    A series of environmental policies have been implemented in the European Union (EU) to decrease nitrogen (N) emissions from agriculture. The Nitrates Directive (ND) is one of the main policies; it aims to reduce nitrate leaching from agriculture through a number of measures. A study was carried out to quantify the effects of the ND in the EU-27 on the leaching and runoff of nitrate (NO3(-)) to groundwater and surface waters, and on the emissions of ammonia (NH3), nitrous oxide (N2O), nitrogen oxides (NO(x)) and dinitrogen (N2) to the atmosphere. We formulated a scenario with and a scenario without implementation of the ND. The model MITERRA-Europe was used to calculate N emissions on a regional level in the EU-27 for the period 2000-2008. The calculated total N loss from agriculture in the EU-27 was 13 Mton N in 2008, with 53% as N2, 22% as NO3, 21% as NH3, 3% as N2O, and 1% as NO(x). The N emissions and leaching in the EU-27 slightly decreased in the period 2000-2008. Total emissions in the EU in 2008 were smaller with implementation of the ND than without the ND, by 3% for NH3, 6% for N2O, 9% for NO(x), and 16% for N leaching and runoff in 2008. However, regional differences were large. The lower emissions with ND were mainly due to the lower N inputs by fertilizers and manures. In conclusion, implementation of the ND decreased both N leaching losses to ground and surface waters, and gaseous emissions to the atmosphere. It is expected that the ND will result in a further decrease in N emissions in EU-27 in the near future, because the implementation of the measures for the ND is expected to become more strict. Copyright © 2013 Elsevier B.V. All rights reserved.

  5. New highly fluorescent pH indicator for ratiometric RGB imaging of pCO2

    International Nuclear Information System (INIS)

    Schutting, Susanne; Klimant, Ingo; Borisov, Sergey M; De Beer, Dirk

    2014-01-01

    A new diketo-pyrrolo-pyrrole (DPP) indicator dye for optical sensing of carbon dioxide is prepared via a simple one step synthesis from commercially available low cost ‘Pigment Orange 73’. The pigment is modified via alkylation of one of the lactam nitrogens with a tert-butylbenzyl group. The indicator dye is highly soluble in organic solvents and in polymers and shows pH-dependent absorption (λ max 501 and 572 nm for the protonated and deprotonated forms, respectively) and emission spectra (λ max 524 and 605 nm for the protonated and deprotonated forms, respectively). Both the protonated and the deprotonated forms show high fluorescence quantum yields (Φ prot 0.86; Φ deprot 0.66). Hence, colorimetric read-out and ratiometric fluorescence intensity measurements are possible. The emission of the two forms of the indicator excellently matches the response of the green and the red channels of an RGB camera. This enables imaging of carbon dioxide distribution with a simple and low cost optical set-up. The sensor based on the new DPP dye shows very high sensitivity and is particularly promising for monitoring atmospheric levels of carbon dioxide. (paper)

  6. A fluorescent probe based on nitrogen doped graphene quantum dots for turn off sensing of explosive and detrimental water pollutant, TNP in aqueous medium

    Science.gov (United States)

    Kaur, Manjot; Mehta, Surinder K.; Kansal, Sushil Kumar

    2017-06-01

    This paper reports the carbonization assisted green approach for the fabrication of nitrogen doped graphene quantum dots (N-GQDs). The obtained N-GQDs displayed good water dispersibility and stability in the wide pH range. The as synthesized N-GQDs were used as a fluorescent probe for the sensing of explosive 2,4,6-trinitrophenol (TNP) in aqueous medium based on fluorescence resonance energy transfer (FRET), molecular interactions and charge transfer mechanism. The quenching efficiency was found to be linear in proportion to the TNP concentration within the range of 0-16 μM with detection limit (LOD) of 0.92 μM. The presented method was successfully applied to the sensing of TNP in tap and lake water samples with satisfactory results. Thus, N-GQDs were used as a selective, sensitive and turn off fluorescent sensor for the detection of perilous water contaminant i.e. TNP.

  7. Effect of fertilizer nitrogen management on N2O emissions in commercial corn fields

    International Nuclear Information System (INIS)

    Zebarth, B.J.; Rochette, P.; Burton, D.L.; Price, M.

    2008-01-01

    Corn crops receive higher fertilizer nitrogen (N) application rates than many other crops. Pre-sidedress soil nitrate tests (PSNT) are used to determine how much fertilizer N is applied at the sidedress of corn crops, and can provide an opportunity to reduce fertilizer N application rates and delay the timing of fertilizer N applications which contribute to nitrous oxide (N 2 O) emissions into the atmosphere. This study examined how the rate and time of fertilizer N application influence N 2 O emissions in corn crops grown in alluvial soils in Atlantic Canada. Starter fertilizer was applied at 45 and 59 kg N per hectare (ha) in 2004 and 2005. Treatments included the application of 75 or 150 kg N per ha banded at a sidedress, and 150 kg N per ha broadcast at the emergence of the crops. Soil mineral N content was measured using a soil core method. Cumulative N 2 O emissions were calculated using a linear interpolation method between sampling dates. Results showed that delays in fertilizer application to the sidedress, and reductions in fertilizer N application reduced nitrate (NO 3 ) intensity but had no impact on cumulative N 2 O emissions. It was concluded that further research is needed to understand controls on denitrification and N 2 O emissions. 28 refs., 2 tabs., 3 figs

  8. Effects of nitrogen fertilization and grazing on the emission of nitrous oxide from grassland

    Energy Technology Data Exchange (ETDEWEB)

    Velthof, G.L.; Brader, A.B.; Oenema, O. [NMI, Dept. of Soil Science and Plant Nutrition, Wageningen Agricultural Univ. (Netherlands)

    1995-11-01

    In the Netherlands, managed grasslands are potentially a large source of nitrous oxide (N{sub 2}O), because of the large nitrogen (N) input and the relatively high ground water levels. To provide insight into the major factors that contribute to N{sub 2}O emission from grassland and to provide quantitative N{sub 2}O emission rates, a monitoring study was carried out on four sites, during March 1992 to March 1994. Fluxes of N{sub 2}O increased after N fertilizer application and grazing, especially during wet conditions. Fluxes were higher from peat soils than from sand and clay soils. Fluxes were low during the winter periods. Total N{sub 2}O losses were 2 to 4.5 times higher on grassland fertilized with 160-460 kg N ha{sup -1} yr{sup -1} than on unfertilized grassland. Losses from grazed grasslands were 1.5 to 3.5 times higher than losses from mown grassland. This study shows that management practice of grassland and soil type are major factors controlling N{sub 2}O emission from grasslands. 2 figs., 3 refs.

  9. Application of microwave energy in the control of DPM, oxides of nitrogen and VOC emissions

    Science.gov (United States)

    Pallavkar, Sameer M.

    The emissions of DPM (diesel particulate matter), NOx (oxides of nitrogen), and toxic VOCs (volatile organic compounds) from diesel engine exhaust gases and other sources such as chemical process industry and manufacturing industry have been a great environmental and health concern. Most control technologies for these emissions require elevated temperatures. The use of microwave energy as a source of heat energy, however, has not been fully explored. In this study, the microwave energy was used as the energy source in three separate emission control processes, namely, the regeneration of diesel particulate filter (DPF) for DPM control, the NOx reduction using a platinum catalyst, and the VOC destruction involving a ceramic based material. The study has demonstrated that microwave heating is an effective method in providing heat for the studied processes. The control efficiencies associated with the microwave-assisted processes have been observed to be high and acceptable. Further research, however, is required for the commercial use of these technologies.

  10. The combustion of biomass - the impact of its types and combustion technologies on the emission of nitrogen oxide

    Directory of Open Access Journals (Sweden)

    Mladenović Milica R.

    2016-01-01

    Full Text Available Harmonization of environmental protection and the growing energy needs of modern society promote the biomass application as a replacement for fossil fuels and a viable option to mitigate the green house gas emissions. For domestic conditions this is particularly important as more than 60% of renewables belongs to biomass. Beside numerous benefits of using biomass for energy purposes, there are certain drawbacks, one of which is a possible high emission of NOx during the combustion of these fuels. The paper presents the results of the experiments with multiple biomass types (soybean straw, cornstalk, grain biomass, sunflower oil, glycerin and paper sludge, using different combustion technologies (fluidized bed and cigarette combustion, with emphasis on the emission of NOx in the exhaust gas. A presentation of the experimental installations is given, as well as an evaluation of the effects of the fuel composition, combustion regimes and technology on the NOx emissions. As the biomass combustion took place at temperatures low enough that thermal and prompt NOx can be neglected, the conclusion is the emissions of nitrogen oxides primarily depend on the biomass composition- it is increasing with the increase of the nitrogen content, and decreases with the increase of the char content which provides catalytic surface for NOx reduction by CO. [Projekat Ministarstva nauke Republike Srbije, br. TR33042: Improvement of the industrial fluidized bed facility, in scope of technology for energy efficient and environmentally feasible combustion of various waste materials in fluidized bed i br. III42011: Development and improvement of technologies for efficient use of energy of several forms of agricultural and forest biomass in an environmentally friendly manner, with the possibility of cogeneration

  11. Current emission trends for nitrogen oxides, sulfur dioxide, and volatile organic compounds by month and state: Methodology and results

    International Nuclear Information System (INIS)

    Kohout, E.J.; Miller, D.J.; Nieves, L.A.; Rothman, D.S.; Saricks, C.L.; Stodolsky, F.; Hanson, D.A.

    1990-08-01

    This report presents estimates of monthly sulfur dioxide (SO 2 ), nitrogen oxides (NO x ), and nonmethane voltatile organic compound (VOC) emissions by sector, region, and state in the contiguous United States for the years 1975 through 1988. This work has been funded as part of the National Acid Precipitation Assessment Program's Emissions and Controls Task Group by the US Department of Energy (DOE) Office of Fossil Energy (FE). The DOE project officer is Edward C. Trexler, DOE/FE Office of Planning and Environment

  12. The Determination of Composite Elements in Zircaloy-2 by X-Ray Fluorescence and Emission Spectrometry Method

    International Nuclear Information System (INIS)

    Dian Anggraini; Rosika Kriswarini; Yusuf N

    2007-01-01

    Analysis of composing elements in zircaloy-2 has been done by Emission Spectrometry method and X-Ray Fluorescence (XRF). The aim of the analysis is to verify conformity between composing elements in zircaloy-2 and the material certificate. Spectrometry Emission method has higher sensitivity in element determination of a material than that of XRF method, so can be estimated that emission spectrometry method has higher accuracy than that of XRF method. The result of qualitative analysis by Emission Spectrometry indicate that the composing elements in zircaloy-2 were Sn, Cr and Ni. However, the qualitative analysis result by XRF method indicated that the composing elements in zircaloy 2 were Sn, Cr, Ni and Fe. Fe element can not be analysed by Emission Spectrometry method because Emission Spectrometer did not equipped with Fe detector. The quantitative analysis result of the composing elements in the material with both methods showed that Sn, Cr and Ni concentration of zircaloy 2 existed in concentration ranges of the material certificate. Result of statistical test (F and t-test) of analysis result of both methods can be used for analyzing composing elements in zircaloy 2. Emission Spectrometry method was more sensitive and accurate for determining Cr and Ni element in zircaloy 2 than that of emission Spectrometry method but both methods had same accuracy. The precision of measurement of Sn, Cr and Ni element using XRF method was better than that of Emission spectrometry method. (author)

  13. Synthesis of biocompatible and highly photoluminescent nitrogen doped carbon dots from lime: Analytical applications and optimization using response surface methodology

    Energy Technology Data Exchange (ETDEWEB)

    Barati, Ali [Faculty of Chemistry, Institute for Advanced Studies in Basic Sciences, Zanjan (Iran, Islamic Republic of); Shamsipur, Mojtaba, E-mail: mshamsipur@yahoo.com [Department of Chemistry, Razi University, Kermanshah (Iran, Islamic Republic of); Arkan, Elham [Nano Drug Delivery Research Center Kermanshah University of Medical Sciences, Kermanshah (Iran, Islamic Republic of); Hosseinzadeh, Leila [Novel Drug Delivery Research Center, Faculty of Pharmacy, Kermanshah University of Medical Sciences, Kermanshah (Iran, Islamic Republic of); Abdollahi, Hamid, E-mail: abd@iasbs.ac.ir [Faculty of Chemistry, Institute for Advanced Studies in Basic Sciences, Zanjan (Iran, Islamic Republic of)

    2015-02-01

    Herein, a facile hydrothermal treatment of lime juice to prepare biocompatible nitrogen-doped carbon quantum dots (N-CQDs) in the presence of ammonium bicarbonate as a nitrogen source has been presented. The resulting N-CQDs exhibited excitation and pH independent emission behavior; with the quantum yield (QY) up to 40%, which was several times greater than the corresponding value for CQDs with no added nitrogen source. The N-CQDs were applied as a fluorescent probe for the sensitive and selective detection of Hg{sup 2+} ions with a detection limit of 14 nM. Moreover, the cellular uptake and cytotoxicity of N-CQDs at different concentration ranges from 0.0 to 0.8 mg/ml were investigated by using PC12 cells as a model system. Response surface methodology was used for optimization and systematic investigation of the main variables that influence the QY, including reaction time, reaction temperature, and ammonium bicarbonate weight. - Highlights: • High fluorescent N-doped CQDs from lime juice have been prepared. • Response surface methodology was used to optimize and model the main factors. • N-doped CQDs were used in the selective and sensitive detection of Hg(II). • The biocompatibility of prepared N-doped CQDs was conformed using PC12 cells.

  14. Using violet laser-induced chlorophyll fluorescence emission spectra for crop yield assessment of cowpea (Vigna unguiculata (L) Walp) varieties

    Science.gov (United States)

    Anderson, Benjamin; Buah-Bassuah, Paul K.; Tetteh, Jonathan P.

    2004-07-01

    The use of violet laser-induced chlorophyll fluorescence (LICF) emission spectra to monitor the growth of five varieties of cowpea in the University of Cape Coast Botanical Garden is presented. Radiation from a continuous-wave violet laser diode emitting at 396 nm through a fibre is closely incident on in vivo leaves of cowpea to excite chlorophyll fluorescence, which is detected by an integrated spectrometer with CCD readout. The chlorophyll fluorescence spectra with peaks at 683 and 731 nm were used for growth monitoring of the cowpea plants over three weeks and analysed using Gaussian spectral functions with curve fitted parameters to determine the peak positions, area under the spectral curve and the intensity ratio F683/F731. The variation in the intensity ratio of the chlorophyll bands showed sensitive changes indicating the photosynthetic activity of the cowpea varieties. A discussion of the fluorescence result as compared to conventional assessment is presented with regard to discrimination between the cowpea varieties in terms of crop yield performance.

  15. Role of photoexcited nitrogen dioxide chemistry on ozone formation and emission control strategy over the Pearl River Delta, China

    Science.gov (United States)

    A new hydroxyl radical formation pathway via photo-excited nitrogen dioxide chemistry is incorporated into a chemistry-only box model as well as a 3D air quality model to examine its potential role on ozone formation and emission control strategy over the Pearl River Delta region...

  16. Management of industrial sulfur dioxide and nitrogen oxides emissions in Alberta - description of the existing system

    International Nuclear Information System (INIS)

    Macdonald, W.S.; Bietz, B.F.

    1999-01-01

    In addition to being key primary air contaminants, sulfur dioxide and nitrogen oxides are also major contributors to acidic deposition. The current management system for controlling industrial sources of SO(2) and NO(x) emissions in Alberta was developed in the late 1960s/early 1970s. The focus is on control of point source emissions through the use of appropriate technology. The approach taken for managing SO(2) and NO(x) emissions is similar to the approach taken to other industrial air and wastewater pollutants in Alberta. It is a command and control regulatory system. There are three main industry categories in Alberta which emit SO(2): sour gas processing, oil sand plants and thermal power plants. For NO(x) emissions, the two main categories with emissions: are natural gas production and thermal power plants. The two main goals of the existing industrial air quality management systems are to ensire that: (1) emissions from industrial facilities are minimized through the use of best available demonstrated technology, and (2) ambient levels of air contaminants in the vicinity of industrial facilities do not exceed Alberta guidelines. The four main policies which support these two goals of the existing management system are described. There are a number of key components of the existing management system including: ambient guideline levels, source emission standards, plume dispersion modelling, ambient air and source emission monitoring, environmental reporting, emission inventories, and approvals. 32 refs., 13 figs

  17. Time-Resolved Synchronous Fluorescence for Biomedical Diagnosis

    Science.gov (United States)

    Zhang, Xiaofeng; Fales, Andrew; Vo-Dinh, Tuan

    2015-01-01

    This article presents our most recent advances in synchronous fluorescence (SF) methodology for biomedical diagnostics. The SF method is characterized by simultaneously scanning both the excitation and emission wavelengths while keeping a constant wavelength interval between them. Compared to conventional fluorescence spectroscopy, the SF method simplifies the emission spectrum while enabling greater selectivity, and has been successfully used to detect subtle differences in the fluorescence emission signatures of biochemical species in cells and tissues. The SF method can be used in imaging to analyze dysplastic cells in vitro and tissue in vivo. Based on the SF method, here we demonstrate the feasibility of a time-resolved synchronous fluorescence (TRSF) method, which incorporates the intrinsic fluorescent decay characteristics of the fluorophores. Our prototype TRSF system has clearly shown its advantage in spectro-temporal separation of the fluorophores that were otherwise difficult to spectrally separate in SF spectroscopy. We envision that our previously-tested SF imaging and the newly-developed TRSF methods will combine their proven diagnostic potentials in cancer diagnosis to further improve the efficacy of SF-based biomedical diagnostics. PMID:26404289

  18. Spectroscopic and TD-DFT studies on the dual mode fluorescent chemosensors based on pyrene thiosemicarbazones, and its application as molecular-scale logic devices

    Energy Technology Data Exchange (ETDEWEB)

    Basheer, Sabeel M. [Department of Chemistry, National Institute of Technology, Tiruchirappalli 620 015 (India); Willis, Anthony C. [Research School of Chemistry, The Australian National University, Canberra, ACT 2601 (Australia); Sreekanth, Anandaram, E-mail: sreekanth@nitt.edu [Department of Chemistry, National Institute of Technology, Tiruchirappalli 620 015 (India)

    2017-03-15

    Two newly synthesised pyrene based molecules are hereby reported as molecular switches. The absorption and emission response for receptors with and without F{sup −}, CN{sup −} and Cu{sup 2+} ions can mimic multiple logic gate such as AND, NOR, XNOR, OR, XOR, INHIBITION and TRANSFER gates. The fluorescence reversibility was checked with the alternative addition of fluoride and calcium ions, which can be explained by the “Read-Erase-Read-Write” logic loop. The calculated binding constant value show PyBTSC is better chemosensor than PyCTSC, and the binding affinity is in the order of Cu{sup 2+}Г‹Ж’F{sup -}Г‹Ж’CN{sup −.} The detailed mechanism was investigated using DFT and TD-DFT calculations. The fluorescence quenching behaviour of receptor-F complex can be explained by PET mechanism along with ESPT process. The proton attached to the nitrogen which is adjacent to pyrene moiety is first make the hydrogen bond with fluoride ion at the excited state, which has confirmed by natural bond orbital (NBO) and potential energy surface (PES) analysis. - Graphical abstract: The newly synthesised thiocarbazone derivates used as an effective and selective colourimetric and “turn on” fluorescence sensor for copper ion and ‘turn off’ for fluoride and cyanide anion. The presence and absence of ions were considered as input signals and the corresponding absorption and emission responses were consired as output. The proton transfer from the nitrogen adjacent to pyrene moiety, and which takes place at the excited state (ESPT).

  19. Carbon "Quantum" Dots for Fluorescence Labeling of Cells.

    Science.gov (United States)

    Liu, Jia-Hui; Cao, Li; LeCroy, Gregory E; Wang, Ping; Meziani, Mohammed J; Dong, Yiyang; Liu, Yuanfang; Luo, Pengju G; Sun, Ya-Ping

    2015-09-02

    The specifically synthesized and selected carbon dots of relatively high fluorescence quantum yields were evaluated in their fluorescence labeling of cells. For the cancer cell lines, the cellular uptake of the carbon dots was generally efficient, resulting in the labeling of the cells with bright fluorescence emissions for both one- and two-photon excitations from predominantly the cell membrane and cytoplasm. In the exploration on labeling the live stem cells, the cellular uptake of the carbon dots was relatively less efficient, though fluorescence emissions could still be adequately detected in the labeled cells, with the emissions again predominantly from the cell membrane and cytoplasm. This combined with the observed more efficient internalization of the same carbon dots by the fixed stem cells might suggest some significant selectivity of the stem cells toward surface functionalities of the carbon dots. The needs and possible strategies for more systematic and comparative studies on the fluorescence labeling of different cells, including especially live stem cells, by carbon dots as a new class of brightly fluorescent probes are discussed.

  20. Rocket-borne EUV-visible emission measurements

    International Nuclear Information System (INIS)

    Schmidtke, G.; Baker, K.D.; Stasek, G.

    1982-01-01

    Two rocket-borne experiments for measuring EUV atmospheric emissions have been conducted. The first measured emissions at 391.4 nm and 557.7 nm, and the second measured emissions in the range from 50 to 650 nm. Height profiles of selected auroral emissions from atomic oxygen at 130.4 nm (exhibiting resonant radiation diffusion) and from atomic oxygen at 557.7 nm, and from neutral and ionized molecular nitrogen are shown. Some details of the recorded spectra are given. In the shorter wavelength regions, emissions from atomic oxygen and nitrogen dominate. Over 140 nm, Lyman-Birge-Hopfield bands, second positive bands and Vegard-Kaplan bands of molecular nitrogen contribute most strongly except for some atomic lines. The Lyman-Birge-Hopfield bands of molecular nitrogen are relatively weak during the auroral arc as compared to the diffuse aurora

  1. Nitrogen rate strategies for reducing yield-scaled nitrous oxide emissions in maize

    Science.gov (United States)

    Zhao, Xu; Nafziger, Emerson D.; Pittelkow, Cameron M.

    2017-12-01

    Mitigating nitrogen (N) losses from agriculture without negatively impacting crop productivity is a pressing environmental and economic challenge. Reductions in N fertilizer rate are often highlighted as a solution, yet the degree to which crop yields and economic returns may be impacted at the field-level remains unclear, in part due to limited data availability. Farmers are risk averse and potential yield losses may limit the success of voluntary N loss mitigation protocols, thus understanding field-level yield tradeoffs is critical to inform policy development. Using a case study of soil N2O mitigation in the US Midwest, we conducted an ex-post assessment of two economic and two environmental N rate reduction strategies to identify promising practices for maintaining maize yields and economic returns while reducing N2O emissions per unit yield (i.e. yield-scaled emissions) compared to an assumed baseline N input level. Maize yield response data from 201 on-farm N rate experiments were combined with an empirical equation predicting N2O emissions as a function of N rate. Results indicate that the economic strategy aimed at maximizing returns to N (MRTN) led to moderate but consistent reductions in yield-scaled N2O emissions with small negative impacts on yield and slight increases in median returns. The economic optimum N rate strategy reduced yield-scaled N2O emissions in 75% of cases but increased them otherwise, challenging the assumption that this strategy will automatically reduce environmental impacts per unit production. Both environmental strategies, one designed to increase N recovery efficiency and one to balance N inputs with grain N removal, further reduced yield-scaled N2O emissions but were also associated with negative yield penalties and decreased returns. These results highlight the inherent tension between achieving agronomic and economic goals while reducing environmental impacts which is often overlooked in policy discussions. To enable the

  2. Development of dual-emission ratiometric probe-based on fluorescent silica nanoparticle and CdTe quantum dots for determination of glucose in beverages and human body fluids.

    Science.gov (United States)

    Zhai, Hong; Feng, Ting; Dong, Lingyu; Wang, Liyun; Wang, Xiangfeng; Liu, Hailing; Liu, Yuan; Chen, Luan; Xie, MengXia

    2016-08-01

    A novel dual emission ratiometric fluorescence probe for determination of glucose has been developed. The reference dye fluorescence isothiocyanate (FITC) has been encapsulated in the silica nanoparticles and then the red emission CdTe QDs were grafted on the surface of the silica particles to obtain the fluorescence probe. With glucose and dopamine as substrates, the glucose level was proportional to the fluorescence ratio change of above probe caused by dopamine oxidation, which was produced via bienzyme catalysis (glucose oxidase and horseradish peroxidase). The established approach was sensitive and selective, and has been applied to determine the glucose in beverage, urine and serum samples. The average recoveries of the glucose at various spiking levels ranged from 95.5% to 108.9% with relative standard deviations from 1.5% to 4.3%. The results provided a clue to develop sensors for rapid determination of the target analytes from complex matrices. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Connecting active to passive fluorescence with photosynthesis: a method for evaluating remote sensing measurements of Chl fluorescence.

    Science.gov (United States)

    Magney, Troy S; Frankenberg, Christian; Fisher, Joshua B; Sun, Ying; North, Gretchen B; Davis, Thomas S; Kornfeld, Ari; Siebke, Katharina

    2017-09-01

    Recent advances in the retrieval of Chl fluorescence from space using passive methods (solar-induced Chl fluorescence, SIF) promise improved mapping of plant photosynthesis globally. However, unresolved issues related to the spatial, spectral, and temporal dynamics of vegetation fluorescence complicate our ability to interpret SIF measurements. We developed an instrument to measure leaf-level gas exchange simultaneously with pulse-amplitude modulation (PAM) and spectrally resolved fluorescence over the same field of view - allowing us to investigate the relationships between active and passive fluorescence with photosynthesis. Strongly correlated, slope-dependent relationships were observed between measured spectra across all wavelengths (F λ , 670-850 nm) and PAM fluorescence parameters under a range of actinic light intensities (steady-state fluorescence yields, F t ) and saturation pulses (maximal fluorescence yields, F m ). Our results suggest that this method can accurately reproduce the full Chl emission spectra - capturing the spectral dynamics associated with changes in the yields of fluorescence, photochemical (ΦPSII), and nonphotochemical quenching (NPQ). We discuss how this method may establish a link between photosynthetic capacity and the mechanistic drivers of wavelength-specific fluorescence emission during changes in environmental conditions (light, temperature, humidity). Our emphasis is on future research directions linking spectral fluorescence to photosynthesis, ΦPSII, and NPQ. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  4. Combining biochar, zeolite and wood vinegar for composting of pig manure: The effect on greenhouse gas emission and nitrogen conservation.

    Science.gov (United States)

    Wang, Quan; Awasthi, Mukesh Kumar; Ren, Xiuna; Zhao, Junchao; Li, Ronghua; Wang, Zhen; Wang, Meijing; Chen, Hongyu; Zhang, Zengqiang

    2018-04-01

    The effect of enhancing wood vinegar (WV) with a mixture of biochar (B) and zeolite (Z) to compost pig manure (PM) in a 130 L reactor was evaluated to determine the levels of greenhouse gas (GHG) and ammonia emissions. Six treatments were prepared in a 2:1 ratio of PM mixed with wheat straw (WS; dry weight basis): PM + WS (control), PM + WS + 10%B, PM + WS + 10%B + 10%Z, and PM + WS with 0.5%, 1.0% and 2.0%WV combined with 10%B + 10%Z. These were composted for 50 days, and the results indicated that the combined use of B, Z, and WV could shorten the thermophilic phase and improve the maturity of compost compared to the control treatment. In addition, WV mixed with B and Z could reduce ammonia loss by 64.45-74.32% and decrease CO 2 , CH 4 , and N 2 O emissions by 33.90-46.98%, 50.39-61.15%, and 79.51-81.10%, respectively. Furthermore, compared to treatments in which B and B + Z were added, adding WV was more efficient to reduce the nitrogen and carbon loss, and the 10%B + 10%Z + 2%WV treatment presented the lowest loss of carbon (9.16%) and nitrogen (0.75%). Based on the maturity indexes used, nitrogen conservation, and efficiency of GHG emissions reduction, the treatment 10%B + 10%Z + 2%WV is suggested for efficient PM composting. Copyright © 2018 Elsevier Ltd. All rights reserved.

  5. A ratiometric nanoprobe based on silver nanoclusters and carbon dots for the fluorescent detection of biothiols

    Science.gov (United States)

    Zhang, Shuming; Lin, Bixia; Yu, Ying; Cao, Yujuan; Guo, Manli; Shui, Lingling

    2018-04-01

    Ratiometric fluorescent probes could eliminate the influence from experimental factors and improve the detection accuracy. In this article, a ratiometric nanoprobe was constructed based on silver nanoclusters (AgNCs) with nitrogen-doped carbon dots (NCDs) and used for the detection of biothiols. The fluorescence peak of AgNCs was observed at 650 nm with excitation wavelength at 370 nm. In order to construct the ratiometric fluorescent probe, NCDs with the excitation and emission wavelengths at 370 nm and 450 nm were selected. After adding AgNCs, the fluorescence of NCDs was quenched. The mechanism of the fluorescence quenching was studied by fluorescence, UV-Vis absorption and the fluorescence lifetime spectra. The results indicated that the quenching could be ascribed to the inner filter effect (IFE). With the addition of biothiols, the fluorescence of AgNCs at 650 nm decreased due to the breakdown of AgNCs, and the fluorescence of NCDs at 450 nm recovered accordingly. Thus, the relationship between the ratio of the fluorescence intensities (I450/I650) and biothiol concentration was used to establish the determination method for biothiols. Cysteine (Cys) was taken as the model of biothiols, and the working curve for Cys was I450/I650 = 0.60CCys - 1.86 (CCys: μmol/L) with the detection limit of 0.14 μmol/L (S/N = 3). Then, the method was used for the detection of Cys in human urine and serum samples with satisfactory accuracy and recovery ratios. Furthermore, the probe could be applied for the visual semi-quantitative determination of Cys by naked eyes.

  6. Synthesis and novel fluorescence phenomenon of terbium(III) complex with N, N',N' -tris (2-benzimidazolmethyl) amine

    International Nuclear Information System (INIS)

    Yang, Tianlin; Gao, Min; Yang, Jinhui; Qin, Wenwu

    2010-01-01

    A benzimidazole ligand with a tripodal structure, N, N', N' -tris (2-benzimidazolmethyl) amine, and its terbium (III) complex has been synthesized. The complex has been characterized by element analysis, IR spectra, mass spectra, thermal analysis and molar conductivity. The terbium ion is found to coordinate with the nitrogen atoms (= N-) of imidazole ring and the bridgehead nitrogen atom. The fluorescence properties of the complex in aqueous solutions have been studied. Under excitation of UV light, the complex exhibits characteristic fluorescence of terbium ion. The luminescence of terbium complex in aqueous solutions is strongly enhanced by H + concentration. This phenomenon makes the new complex favorable for use in fluorescence switches and sensors. The mechanism of the fluorescence enhancement by protonation of the nitrogen atoms (-NH-) of imidazole ring is due to the suppressed photoinduced electron transfer fluorescence quenching on addition of acid. (author)

  7. Highly Sensitive Ratiometric Fluorescent Sensor for Trinitrotoluene Based on the Inner Filter Effect between Gold Nanoparticles and Fluorescent Nanoparticles.

    Science.gov (United States)

    Lu, Hongzhi; Quan, Shuai; Xu, Shoufang

    2017-11-08

    In this work, we developed a simple and sensitive ratiometric fluorescent assay for sensing trinitrotoluene (TNT) based on the inner filter effect (IFE) between gold nanoparticles (AuNPs) and ratiometric fluorescent nanoparticles (RFNs), which was designed by hybridizing green emissive carbon dots (CDs) and red emissive quantum dots (QDs) into a silica sphere as a fluorophore pair. AuNPs in their dispersion state can be a powerful absorber to quench CDs, while the aggregated AuNPs can quench QDs in the IFE-based fluorescent assays as a result of complementary overlap between the absorption spectrum of AuNPs and emission spectrum of RFNs. As a result of the fact that TNT can induce the aggregation of AuNPs, with the addition of TNT, the fluorescent of QDs can be quenched, while the fluorescent of CDs would be recovered. Then, ratiometric fluorescent detection of TNT is feasible. The present IFE-based ratiometric fluorescent sensor can detect TNT ranging from 0.1 to 270 nM, with a detection limit of 0.029 nM. In addition, the developed method was successfully applied to investigate TNT in water and soil samples with satisfactory recoveries ranging from 95 to 103%, with precision below 4.5%. The simple sensing approach proposed here could improve the sensitivity of colorimetric analysis by changing the ultraviolet analysis to ratiometric fluorescent analysis and promote the development of a dual-mode detection system.

  8. Highly selective ratiometric fluorescent detection of Fe{sup 3+} with a polyphenyl derivative

    Energy Technology Data Exchange (ETDEWEB)

    Li, Zhan-Xian, E-mail: lizx@zzu.edu.cn [The College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450001 (China); Zhou, Wan; Zhang, Li-Feng; Yuan, Rui-Li; Liu, Xing-Jiang; Wei, Liu-He [The College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450001 (China); Yu, Ming-Ming, E-mail: yumm@zzu.edu.cn [The College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450001 (China)

    2013-04-15

    Compared with other fluorescent probes, ratiometric fluorescence responses are more attractive because the ratio between the two emission intensities can be used to measure the analyte concentration and provide a built-in correction for environmental effects. A highly selective and sensitive ratiometric fluorescent probe for Fe{sup 3+} was synthesized, which exhibits an enhanced fluorescence with a large red-shift in emission from 361 to 455 nm upon addition of Fe{sup 3+}. The red-shift of the emission peak can be ascribed to the reformed orbital, and the increase of emission intensity may be ascribed to the inhibition of the rotation of C–C bonds between each two aromatic rings. -- Graphical abstract: A highly selective and sensitive ratiometric fluorescent probe for Fe{sup 3+} was synthesized, which exhibits an enhanced fluorescence with a large red-shift in emission from 361 to 455 nm upon addition of Fe{sup 3+}. Highlights: ► A ratiometric fluorescent probe for Fe{sup 3+} was synthesized. ► The probe exhibits an enhanced fluorescence with a red-shift upon addition of Fe{sup 3+}. ► Inhibition of the rotation of C–C bonds was possible detection mechanism for Fe{sup 3+}.

  9. U(IV) fluorescence spectroscopy. A new speciation tool

    Energy Technology Data Exchange (ETDEWEB)

    Lehmann, Susanne; Brendler, Vinzenz [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Surface Processes; Steudtner, Robin [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Inst. of Resource Ecology

    2017-06-01

    We combined absorption and fluorescence spectroscopy to study the speciation of U(IV) in solution in concentrations down to 10{sup -6} M uranium. With our time-resolved laser-induced fluorescence setup we could determine the fluorescence decay time of U(IV) in perchloric as well as in chloric acid with 2.6 ± 0.3 ns at room temperature and 148.4 ± 6.5 ns at liquid nitrogen temperature. For the U(IV) sulfate system, we observed a bathochromic shift and a peak shape modification in the fluorescence spectra with increasing sulfate concentration in solution. Thus, the potential of U(IV) fluorescence for speciation analysis could be proven.

  10. Increasing importance of deposition of reduced nitrogen in the United States

    Science.gov (United States)

    Yi Li; Bret A. Schichtel; John T. Walker; Donna B. Schwede; Xi Chen; Christopher M. B. Lehmann; Melissa A. Puchalski; David A. Gay; Jeffrey L. Collett

    2016-01-01

    Rapid development of agriculture and fossil fuel combustion greatly increased US reactive nitrogen emissions to the atmosphere in the second half of the 20th century, resulting in excess nitrogen deposition to natural ecosystems. Recent efforts to lower nitrogen oxides emissions have substantially decreased nitrate wet deposition. Levels of wet ammonium...

  11. Precision analysis of 15N-labelled samples with the emission spectrometer NOI-5 for nitrogen balance in field trials

    International Nuclear Information System (INIS)

    Lippold, H.

    1984-01-01

    A technique was adapted for the preparation of samples with 15 N to be analyzed with the emission spectrometer NOI-5. This technique is based on methods of analyzing 15 N labelled gas samples in denitrification experiments. Nitrogen released from ammonium compounds by using hypobromite is injected into a repeatedly usable gaseous discharge tube where it is freed from water traces by means of the molecular sieve 5A. The described procedure of activating the molecular sieve allows to record spectra of reproducible quality thus promising an accuracy of analysis of +- 0.003 at% in the range of natural isotope frequency and the possibility of soil nitrogen analysis in field trials with fertilizers of low nitrogen content (3 to 6.5 at%; corresponding with 0.055 to 0.14% N/sub t/ of soils) without being dependent on mass spectrometers. (author)

  12. The injury and cumulative effects on human skin by UV exposure from artificial fluorescence emission.

    Science.gov (United States)

    Tian, Yan; Liu, Wei; Niu, TianHui; Dai, CaiHong; Li, Xiaoxin; Cui, Caijuan; Zhao, Xinyan; E, Yaping; Lu, Hui

    2014-01-01

    The injury and cumulative effects of UV emission from fluorescence lamp were studied. UV intensity from fluorescence lamp was measured, and human skin samples (hips, 10 volunteers) were exposed to low-dose UV irradiation (three times per week for 13 consecutive weeks). Three groups were examined: control group without UV radiation; low-dose group with a cumulative dose of 50 J cm(-2) which was equivalent to irradiation of the face during indoor work for 1.5 years; and high-dose group with 1000 J cm(-2) cumulative dose equivalent to irradiation of the face during outdoor activities for 1 year. Specific indicators were measured before and after UVA irradiation. The findings showed that extending the low-dose UVA exposure decreased the skin moisture content and increased the transepidermal water loss as well as induced skin color changes (decreased L* value, increased M index). Furthermore, irradiated skin showed an increased thickness of cuticle and epidermis, skin edema, light color and unclear staining collagen fibers in the dermis, and elastic fiber fragmentation. In addition, MMP-1, p53 and SIRT1 expression was also increased. Long-term exposure of low-dose UVA radiation enhanced skin photoaging. The safety of the fluorescent lamp needs our attention. © 2014 The American Society of Photobiology.

  13. Contribution of chlorophyll fluorescence to the apparent vegetation reflectance

    International Nuclear Information System (INIS)

    Campbell, P.K. Entcheva; Middleton, E.M.; Corp, L.A.; Kim, M.S.

    2008-01-01

    Current strategies for monitoring the physiologic status of terrestrial vegetation rely on remote sensing reflectance data, which provide estimates of vigor based primarily on chlorophyll content. Chlorophyll fluorescence (ChlF) measurements offer a non-destructive alternative and a more direct approach for diagnosis of vegetation stress before a significant reduction in chlorophyll content has occurred. Thus, technology based on ChlF may allow more accurate carbon sequestration estimates and earlier stress detection than is possible when using reflectance data alone. However, the observed apparent vegetation reflectance (Ra) in reality includes contributions from both the reflected and fluoresced radiation. The aim of this study is to determine the relative contributions of reflectance and ChlF fractions to Ra in the red to near-infrared region (650-800 nm) of the spectrum. The practical objectives of the study are to: 1) evaluate the relationship between ChlF and reflectance at the foliar level for corn, soybean and maple; and 2) for corn, determine if the relationship established for healthy vegetation changes under nitrogen (N) deficiency. To obtain generally applicable results, experimental measurements were conducted on unrelated crop and tree species (corn, soybean and maple) under controlled conditions and a gradient of inorganic N fertilization levels. Optical reflectance spectra and actively induced ChlF emissions were collected on the same foliar samples, in conjunction with measurements of photosynthetic function, pigment levels, and carbon (C) and N content. The spectral trends were examined for similarities. On average, 10-20% of Ra at 685 nm was actually due to ChlF. The spectral trends in steady state and maximum fluorescence varied significantly, with steady state fluorescence (especially red, 685 nm) showing higher ability for species and treatment separation. The relative contribution of ChlF to Ra varied significantly among species, with maple

  14. Greenhouse gas emissions from agricultural soils in Austria

    International Nuclear Information System (INIS)

    Strebl, F.; Gebetsroither, E.; Orthofer, R.

    2002-07-01

    This report documents the calculations of anthropogenic greenhouse gas emissions in Austria of the IPCC-sector 'Agricultural Soils' for the period 1980 to 2001. According to available information, CH 4 emissions from agricultural soils are very small and thus irrelevant. N 2 O emissions were calculated according to the IPCC method; emission sources considered include direct emissions from nitrogen inputs to soils (mineral and organic fertilizers, crop residues, sewage sludge application, biological fixation) as well as indirect emissions (from atmospheric nitrogen deposition and nitrogen leaching) plus emissions from nitrogen input through grazing animal excreta. NH 3 and NO x emissions were calculated according to the CORINAIR method; sources considered were nitrogen inputs through fertilization as well as emissions from unfertilized cultures. In the year 1990 total emissions were 5.680 t N 2 O-N, 24.628 t NH 3 -N and 1.376 t NO x N. In the period 1980-2001 there were considerable fluctuations of emissions, caused by an inter annual variability of crop production and fertilizer consumption data. However, there are no significant emission trends in the past 20 years. Uncertainties were determined through a Monte-Carlo-based simulation; the standard deviation of a normal uncertainty distribution is 24 % for N 2 O, 13 % for NH 3 , and 18 % for NO x . (author)

  15. Laser induced fluorescence of some plant leaves

    International Nuclear Information System (INIS)

    Helmi, M.S.; Mohamed, M.M.; Amer, R.; Elshazly, O.; Elraey, M.

    1992-01-01

    Laser induced fluorescence (LIF) is successfully used as a technique for remote detection of spectral characteristics of some plants. A pulsed nitrogen laser at 337.1 nm is used to excite cotton, corn and rice leaves. The fluorescence spectrum is detected in the range from 340 nm to 820 nm. It is found that, these plant leaves have common fluorescence maxima at 440 nm, 685 nm and 740 nm. plant leaves are also found to be identifiable by the ratio of the fluorescence intensity at 440 nm to that at 685 nm. The present technique can be further used as a means of assessing, remotely, plant stresses. 5 fig

  16. Mitigating fluorescence spectral overlap in wide-field endoscopic imaging

    Science.gov (United States)

    Hou, Vivian; Nelson, Leonard Y.; Seibel, Eric J.

    2013-01-01

    Abstract. The number of molecular species suitable for multispectral fluorescence imaging is limited due to the overlap of the emission spectra of indicator fluorophores, e.g., dyes and nanoparticles. To remove fluorophore emission cross-talk in wide-field multispectral fluorescence molecular imaging, we evaluate three different solutions: (1) image stitching, (2) concurrent imaging with cross-talk ratio subtraction algorithm, and (3) frame-sequential imaging. A phantom with fluorophore emission cross-talk is fabricated, and a 1.2-mm ultrathin scanning fiber endoscope (SFE) is used to test and compare these approaches. Results show that fluorophore emission cross-talk could be successfully avoided or significantly reduced. Near term, the concurrent imaging method of wide-field multispectral fluorescence SFE is viable for early stage cancer detection and localization in vivo. Furthermore, a means to enhance exogenous fluorescence target-to-background ratio by the reduction of tissue autofluorescence background is demonstrated. PMID:23966226

  17. Estimating nitrogen oxides emissions at city scale in China with a nightlight remote sensing model.

    Science.gov (United States)

    Jiang, Jianhui; Zhang, Jianying; Zhang, Yangwei; Zhang, Chunlong; Tian, Guangming

    2016-02-15

    Increasing nitrogen oxides (NOx) emissions over the fast developing regions have been of great concern due to their critical associations with the aggravated haze and climate change. However, little geographically specific data exists for estimating spatio-temporal trends of NOx emissions. In order to quantify the spatial and temporal variations of NOx emissions, a spatially explicit approach based on the continuous satellite observations of artificial nighttime stable lights (NSLs) from the Defense Meteorological Satellite Program/Operational Linescan System (DMSP/OLS) was developed to estimate NOx emissions from the largest emission source of fossil fuel combustion. The NSL based model was established with three types of data including satellite data of nighttime stable lights, geographical data of administrative boundaries, and provincial energy consumptions in China, where a significant growth of NOx emission has experienced during three policy stages corresponding to the 9th-11th)Five-Year Plan (FYP, 1995-2010). The estimated national NOx emissions increased by 8.2% per year during the study period, and the total annual NOx emissions in China estimated by the NSL-based model were approximately 4.1%-13.8% higher than the previous estimates. The spatio-temporal variations of NOx emissions at city scale were then evaluated by the Moran's I indices. The global Moran's I indices for measuring spatial agglomerations of China's NOx emission increased by 50.7% during 1995-2010. Although the inland cities have shown larger contribution to the emission growth than the more developed coastal cities since 2005, the High-High clusters of NOx emission located in Beijing-Tianjin-Hebei regions, the Yangtze River Delta, and the Pearl River Delta should still be the major focus of NOx mitigation. Our results indicate that the readily available DMSP/OLS nighttime stable lights based model could be an easily accessible and effective tool for achieving strategic decision making

  18. Plasma Wind Tunnel Investigation of European Ablators in Nitrogen/Methane Using Emission Spectroscopy

    Directory of Open Access Journals (Sweden)

    Ricarda Wernitz

    2013-01-01

    Full Text Available For atmospheric reentries at high enthalpies ablative heat shield materials are used, such as those for probes entering the atmosphere of Saturn’s moon Titan, such as Cassini-Huygens in December, 2004. The characterization of such materials in a nitrogen/methane atmosphere is of interest. A European ablative material, AQ60, has been investigated in plasma wind tunnel tests at the IRS plasma wind tunnel PWK1 using the magnetoplasma dynamic generator RD5 as plasma source in a nitrogen/methane atmosphere. The dimensions of the samples are 45 mm in length with a diameter of 39 mm. The actual ablator has a thickness of 40 mm. The ablator is mounted on an aluminium substructure. The experiments were conducted at two different heat flux regimes, 1.4 MW/m2 and 0.3 MW/m2. In this paper, results of emission spectroscopy at these plasma conditions in terms of plasma species’ temperatures will be presented, including the investigation of the free-stream species, N2 and N2+, and the major erosion product C2, at a wavelength range around 500 nm–600 nm.

  19. Fluorescence lifetime selectivity in excitation-emission matrices for qualitative analysis of a two-component system

    International Nuclear Information System (INIS)

    Millican, D.W.; McGown, L.B.

    1989-01-01

    Steady-state fluorescence excitation-emission matrices (EEMs), and phase-resolved EEMs (PREEMs) collected at modulation frequencies of 6, 18, and 30 MHz, were used for qualitative analysis of mixtures of benzo[k]fluoranthene (τ = 8 ns) and benzo[b]fluoranthene (τ = 29 ns) in ethanol. The EEMs of the individual components were extracted from mixture EEMs by means of wavelength component vector-gram (WCV) analysis. Phase resolution was found to be superior to steady-state measurements for extraction of the component spectra, for mixtures in which the intensity contributions from the two components are unequal

  20. Atomic imaging by x-ray-fluorescence holography and electron-emission holography: A comparative theoretical study

    International Nuclear Information System (INIS)

    Len, P.M.; Thevuthasan, S.; Fadley, C.S.; Kaduwela, A.P.; Van Hove, M.A.

    1994-01-01

    We consider from a theoretical viewpoint the direct imaging of atoms at and near the surfaces of solids by both x-ray-fluorescence holography (XFH) and electron-emission holography (EEH). The more ideal nature of x-ray scattering makes XFH images superior to those in single-energy EEH. The overlap of real and twin features for pairs of atoms at ±a can cause their XFH or EEH atomic images to cancel for certain combinations of wave vector and |a|. The relative merits of XFH and EEH for structure studies are considered

  1. 75 FR 31711 - Approval and Promulgation of Air Quality Implementation Plans; Delaware; Control of Nitrogen...

    Science.gov (United States)

    2010-06-04

    ... Promulgation of Air Quality Implementation Plans; Delaware; Control of Nitrogen Oxide Emissions From Industrial... controlling nitrogen oxide (NOx) emissions from industrial boilers. This action is being taken under the Clean...--Control of Nitrogen Oxide Emissions from Industrial Boilers and Process Heaters at Petroleum Refineries in...

  2. 75 FR 12168 - Approval and Promulgation of Air Quality Implementation Plans; Delaware; Control of Nitrogen...

    Science.gov (United States)

    2010-03-15

    ... Promulgation of Air Quality Implementation Plans; Delaware; Control of Nitrogen Oxide Emissions From Industrial... the State of Delaware. The revision adds a new section, Section 2--Control of Nitrogen Oxide Emissions.../SIP Regulation No. 42-- Specific Emission Control Requirements for controlling nitrogen oxide (NO X...

  3. Stink Bug Feeding Induces Fluorescence in Developing Cotton Bolls

    Directory of Open Access Journals (Sweden)

    Toews Michael D

    2011-08-01

    Full Text Available Abstract Background Stink bugs (Hemiptera: Pentatomidae comprise a critically important insect pest complex affecting 12 major crops worldwide including cotton. In the US, stink bug damage to developing cotton bolls causes boll abscission, lint staining, reduced fiber quality, and reduced yields with estimated losses ranging from 10 to 60 million dollars annually. Unfortunately, scouting for stink bug damage in the field is laborious and excessively time consuming. To improve scouting accuracy and efficiency, we investigated fluorescence changes in cotton boll tissues as a result of stink bug feeding. Results Fluorescent imaging under long-wave ultraviolet light showed that stink bug-damaged lint, the inner carpal wall, and the outside of the boll emitted strong blue-green fluorescence in a circular region near the puncture wound, whereas undamaged tissue emissions occurred at different wavelengths; the much weaker emission of undamaged tissue was dominated by chlorophyll fluorescence. We further characterized the optimum emission and excitation spectra to distinguish between stink bug damaged bolls from undamaged bolls. Conclusions The observed characteristic fluorescence peaks associated with stink bug damage give rise to a fluorescence-based method to rapidly distinguish between undamaged and stink bug damaged cotton bolls. Based on the fluorescent fingerprint, we envision a fluorescence reflectance imaging or a fluorescence ratiometric device to assist pest management professionals with rapidly determining the extent of stink bug damage in a cotton field.

  4. Hue-shifted monomeric variants of Clavularia cyan fluorescent protein: identification of the molecular determinants of color and applications in fluorescence imaging

    Directory of Open Access Journals (Sweden)

    Davidson Michael W

    2008-03-01

    Full Text Available Abstract Background In the 15 years that have passed since the cloning of Aequorea victoria green fluorescent protein (avGFP, the expanding set of fluorescent protein (FP variants has become entrenched as an indispensable toolkit for cell biology research. One of the latest additions to the toolkit is monomeric teal FP (mTFP1, a bright and photostable FP derived from Clavularia cyan FP. To gain insight into the molecular basis for the blue-shifted fluorescence emission we undertook a mutagenesis-based study of residues in the immediate environment of the chromophore. We also employed site-directed and random mutagenesis in combination with library screening to create new hues of mTFP1-derived variants with wavelength-shifted excitation and emission spectra. Results Our results demonstrate that the protein-chromophore interactions responsible for blue-shifting the absorbance and emission maxima of mTFP1 operate independently of the chromophore structure. This conclusion is supported by the observation that the Tyr67Trp and Tyr67His mutants of mTFP1 retain a blue-shifted fluorescence emission relative to their avGFP counterparts (that is, Tyr66Trp and Tyr66His. Based on previous work with close homologs, His197 and His163 are likely to be the residues with the greatest contribution towards blue-shifting the fluorescence emission. Indeed we have identified the substitutions His163Met and Thr73Ala that abolish or disrupt the interactions of these residues with the chromophore. The mTFP1-Thr73Ala/His163Met double mutant has an emission peak that is 23 nm red-shifted from that of mTFP1 itself. Directed evolution of this double mutant resulted in the development of mWasabi, a new green fluorescing protein that offers certain advantages over enhanced avGFP (EGFP. To assess the usefulness of mTFP1 and mWasabi in live cell imaging applications, we constructed and imaged more than 20 different fusion proteins. Conclusion Based on the results of our

  5. In vivo tumor-targeted dual-modal fluorescence/CT imaging using a nanoprobe co-loaded with an aggregation-induced emission dye and gold nanoparticles.

    Science.gov (United States)

    Zhang, Jimei; Li, Chan; Zhang, Xu; Huo, Shuaidong; Jin, Shubin; An, Fei-Fei; Wang, Xiaodan; Xue, Xiangdong; Okeke, C I; Duan, Guiyun; Guo, Fengguang; Zhang, Xiaohong; Hao, Jifu; Wang, Paul C; Zhang, Jinchao; Liang, Xing-Jie

    2015-02-01

    As an intensely studied computed tomography (CT) contrast agent, gold nanoparticle has been suggested to be combined with fluorescence imaging modality to offset the low sensitivity of CT. However, the strong quenching of gold nanoparticle on fluorescent dyes requires complicated design and shielding to overcome. Herein, we report a unique nanoprobe (M-NPAPF-Au) co-loading an aggregation-induced emission (AIE) red dye and gold nanoparticles into DSPE-PEG(2000) micelles for dual-modal fluorescence/CT imaging. The nanoprobe was prepared based on a facile method of "one-pot ultrasonic emulsification". Surprisingly, in the micelles system, fluorescence dye (NPAPF) efficiently overcame the strong fluorescence quenching of shielding-free gold nanoparticles and retained the crucial AIE feature. In vivo studies demonstrated the nanoprobe had superior tumor-targeting ability, excellent fluorescence and CT imaging effects. The totality of present studies clearly indicates the significant potential application of M-NPAPF-Au as a dual-modal non-invasive fluorescence/X-ray CT nanoprobe for in vivo tumor-targeted imaging and diagnosis. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Spectroscopic investigations of OH- influence on near-infrared fluorescence quenching of Yb3+/Tm3+ co-doped sodium-metaphosphate glasses

    International Nuclear Information System (INIS)

    Terra, I.A.A.; Camargo, A.S.S. de; Terrile, M.C.; Nunes, L.A.O.

    2008-01-01

    Energy transfer processes were studied in two sets of Yb 3+ and Tm 3+ co-doped sodium-metaphosphate glasses, prepared in air and nitrogen atmospheres. Using Foerster, Dexter, and Miyakawa theoretical models, the energy transfer parameters were calculated. The main ion-ion energy transfer processes analyzed were energy migration among Yb 3+ ions, cross-relaxations between Yb 3+ and Tm 3+ ions, and interactions with OH - radicals. The results indicated that Yb→Tm energy transfer favors 1.8 μm emissions, and there is no evidence of concentration quenching up to 2% Tm 2 O 3 doping. As expected, samples prepared in nitrogen atmosphere present higher fluorescence quantum efficiency than those prepared in air, and this feature is specially noted in the near-infrared region, where the interaction with the OH - radicals is more pronounced

  7. Impacts of European livestock production: nitrogen, sulphur, phosphorus and greenhouse gas emissions, land-use, water eutrophication and biodiversity

    International Nuclear Information System (INIS)

    Leip, Adrian; Grizzetti, Bruna; Weiss, Franz; Billen, Gilles; Garnier, Josette; Lassaletta, Luis; Reis, Stefan; Sutton, Mark A; Simpson, David; De Vries, Wim; Westhoek, Henk

    2015-01-01

    Livestock production systems currently occupy around 28% of the land surface of the European Union (equivalent to 65% of the agricultural land). In conjunction with other human activities, livestock production systems affect water, air and soil quality, global climate and biodiversity, altering the biogeochemical cycles of nitrogen, phosphorus and carbon. Here, we quantify the contribution of European livestock production to these major impacts. For each environmental effect, the contribution of livestock is expressed as shares of the emitted compounds and land used, as compared to the whole agricultural sector. The results show that the livestock sector contributes significantly to agricultural environmental impacts. This contribution is 78% for terrestrial biodiversity loss, 80% for soil acidification and air pollution (ammonia and nitrogen oxides emissions), 81% for global warming, and 73% for water pollution (both N and P). The agriculture sector itself is one of the major contributors to these environmental impacts, ranging between 12% for global warming and 59% for N water quality impact. Significant progress in mitigating these environmental impacts in Europe will only be possible through a combination of technological measures reducing livestock emissions, improved food choices and reduced food waste of European citizens. (letter)

  8. Nitrous oxide emissions respond differently to mineral and organic nitrogen sources in contrasting soil types.

    Science.gov (United States)

    Pelster, David E; Chantigny, Martin H; Rochette, Philippe; Angers, Denis A; Rieux, Christine; Vanasse, Anne

    2012-01-01

    The use of various animal manures for nitrogen (N) fertilization is often viewed as a viable replacement for mineral N fertilizers. However, the impacts of amendment type on NO production may vary. In this study, NO emissions were measured for 2 yr on two soil types with contrasting texture and carbon (C) content under a cool, humid climate. Treatments consisted of a no-N control, calcium ammonium nitrate, poultry manure, liquid cattle manure, or liquid swine manure. The N sources were surface applied and immediately incorporated at 90 kg N ha before seeding of spring wheat ( L.). Cumulative NO-N emissions from the silty clay ranged from 2.2 to 8.3 kg ha yr and were slightly lower in the control than in the fertilized plots ( = 0.067). The 2-yr mean NO emission factors ranged from 2.0 to 4.4% of added N, with no difference among N sources. Emissions of NO from the sandy loam soil ranged from 0.3 to 2.2 kg NO-N ha yr, with higher emissions with organic than mineral N sources ( = 0.015) and the greatest emissions with poultry manure ( < 0.001). The NO emission factor from plots amended with poultry manure was 1.8%, more than double that of the other treatments (0.3-0.9%), likely because of its high C content. On the silty clay, the yield-based NO emissions (g NO-N kg grain yield N) were similar between treatments, whereas on the sandy loam, they were greatest when amended with poultry manure. Our findings suggest that, compared with mineral N sources, manure application only increases soil NO flux in soils with low C content. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  9. Synthesis, characterization and fluorescence studies of a novel europium complex based sensor

    International Nuclear Information System (INIS)

    Li Bin; Chen Qiuyun; Wang Yachen; Huang Jing; Li Yang

    2010-01-01

    A novel europium(III) complex was synthesized using TTA (α-thenoyltrifluoroacetone) as the first ligand and H 2 bpdc (2,2'-bipyridine-3,3'-dicarboxylate) as the second ligand. Elemental analysis, thermal analysis, IR and UV-vis spectrum and fluorescence spectrum of the europium(III) complex were carried out. A characteristic Eu 3+ fluorescence emission was observed in ethanol-water (1:1) solution, indicating that the complex is stable in solution and the emission of Eu(III) ions was not influenced by the water molecules. The fluorescence emission of the complex was quenched completely by the Co 2+ and Fe 3+ ions, but the quenched emission was recovered in the presence of glycine. Moreover, the Eu 3+ emission was very sensitive to pH, so the complex can be used as pH-dependent fluorescence probe or chemosensors.

  10. Fluorescent single walled nanotube/silica composite materials

    Science.gov (United States)

    Dattelbaum, Andrew M.; Gupta, Gautam; Duque, Juan G.; Doorn, Stephen K.; Hamilton, Christopher E.; DeFriend Obrey, Kimberly A.

    2013-03-12

    Fluorescent composites of surfactant-wrapped single-walled carbon nanotubes (SWNTs) were prepared by exposing suspensions of surfactant-wrapped carbon nanotubes to tetramethylorthosilicate (TMOS) vapor. Sodium deoxycholate (DOC) and sodium dodecylsulphate (SDS) were the surfactants. No loss in emission intensity was observed when the suspension of DOC-wrapped SWNTs were exposed to the TMOS vapors, but about a 50% decrease in the emission signal was observed from the SDS-wrapped SWNTs nanotubes. The decrease in emission was minimal by buffering the SDS/SWNT suspension prior to forming the composite. Fluorescent xerogels were prepared by adding glycerol to the SWNT suspensions prior to TMOS vapor exposure, followed by drying the gels. Fluorescent aerogels were prepared by replacing water in the gels with methanol and then exposing them to supercritical fluid drying conditions. The aerogels can be used for gas sensing.

  11. Recent changes in anthropogenic reactive nitrogen compounds

    Science.gov (United States)

    Andronache, Constantin

    2014-05-01

    Significant anthropogenic perturbations of the nitrogen cycle are the result of rapid population growth, with mounting need for food and energy production. The increase of reactive nitrogen compounds (such as NOx, HNO3, NH3, and N2O) has a significant impact on human health, environment, and climate. NOx emissions contribute to O3 chemistry, aerosol formation and acidic precipitation. Ammonia is a notable atmospheric pollutant that may deteriorate ecosystems and contribute to respiratory problems. It reacts with acidic gases to form aerosols or is deposited back to ecosystems. The application of fertilizers accounts for most of the N2O production, adding to greenhouse gas emissions. We analyze the change of some reactive nitrogen compounds based on observations, in eastern United States. Results show that the control of NOx and SO2 emissions over the last decades caused a significant decrease of acidic deposition. The nitrate deposition is highest in eastern US, while the ammonium ion concentration is highest in central US regions. Overall, the inorganic nitrogen wet deposition from nitrate and ammonium is enhanced in central, and eastern US. Research shows that sensitive ecosystems in northeastern regions exhibit a slow recovery from the accumulated effects of acidic deposition. Given the growing demand for nitrogen in agriculture and industry, we discuss possible pathways to reduce the impact of excess reactive nitrogen on the environment.

  12. Hyperspectral small animal fluorescence imaging: spectral selection imaging

    Science.gov (United States)

    Leavesley, Silas; Jiang, Yanan; Patsekin, Valery; Hall, Heidi; Vizard, Douglas; Robinson, J. Paul

    2008-02-01

    Molecular imaging is a rapidly growing area of research, fueled by needs in pharmaceutical drug-development for methods for high-throughput screening, pre-clinical and clinical screening for visualizing tumor growth and drug targeting, and a growing number of applications in the molecular biology fields. Small animal fluorescence imaging employs fluorescent probes to target molecular events in vivo, with a large number of molecular targeting probes readily available. The ease at which new targeting compounds can be developed, the short acquisition times, and the low cost (compared to microCT, MRI, or PET) makes fluorescence imaging attractive. However, small animal fluorescence imaging suffers from high optical scattering, absorption, and autofluorescence. Much of these problems can be overcome through multispectral imaging techniques, which collect images at different fluorescence emission wavelengths, followed by analysis, classification, and spectral deconvolution methods to isolate signals from fluorescence emission. We present an alternative to the current method, using hyperspectral excitation scanning (spectral selection imaging), a technique that allows excitation at any wavelength in the visible and near-infrared wavelength range. In many cases, excitation imaging may be more effective at identifying specific fluorescence signals because of the higher complexity of the fluorophore excitation spectrum. Because the excitation is filtered and not the emission, the resolution limit and image shift imposed by acousto-optic tunable filters have no effect on imager performance. We will discuss design of the imager, optimizing the imager for use in small animal fluorescence imaging, and application of spectral analysis and classification methods for identifying specific fluorescence signals.

  13. Nitrogen-Use Efficiency, Nitrous Oxide Emissions, and Cereal Production in Brazil: Current Trends and Forecasts.

    Science.gov (United States)

    Pires, Marcel Viana; da Cunha, Dênis Antônio; de Matos Carlos, Sabrina; Costa, Marcos Heil

    2015-01-01

    The agriculture sector has historically been a major source of greenhouse gas (GHG) emissions into the atmosphere. Although the use of synthetic fertilizers is one of the most common widespread agricultural practices, over-fertilization can lead to negative economic and environmental consequences, such as high production costs, depletion of energy resources, and increased GHG emissions. Here, we provide an analysis to understand the evolution of cereal production and consumption of nitrogen (N) fertilizers in Brazil and to correlate N use efficiency (NUE) with economic and environmental losses as N2O emissions. Our results show that the increased consumption of N fertilizers is associated with a large decrease in NUE in recent years. The CO2 eq. of N2O emissions originating from N fertilization for cereal production were approximately 12 times higher in 2011 than in 1970, indicating that the inefficient use of N fertilizers is directly related to environmental losses. The projected N fertilizer forecasts are 2.09 and 2.37 million ton for 2015 and 2023, respectively. An increase of 0.02% per year in the projected NUE was predicted for the same time period. However, decreases in the projected CO2 eq. emissions for future years were not predicted. In a hypothetical scenario, a 2.39% increase in cereal NUE would lead to $ 21 million savings in N fertilizer costs. Thus, increases in NUE rates would lead not only to agronomic and environmental benefits but also to economic improvement.

  14. Nitrogen source and placement effects on soil nitrous oxide emissions from no-till corn.

    Science.gov (United States)

    Halvorson, Ardell D; Del Grosso, Stephen J

    2012-01-01

    A nitrogen (N) source comparison study was conducted to further evaluate the effects of inorganic N source and placement on growing-season and non-crop period soil nitrous oxide (NO). Commercially available controlled-release N fertilizers were evaluated for their potential to reduce NO emissions from a clay loam soil compared with conventionally used granular urea and urea-ammonium nitrate (UAN) fertilizers in an irrigated no-till (NT) corn ( L.) production system. Controlled-release N fertilizers evaluated were: a polymer-coated urea (ESN), stabilized urea (SuperU), and UAN+AgrotainPlus (SuperU and AgrotainPlus contain nitrification and urease inhibitors). Each N source was surface band applied (202 kg N ha) near the corn row at emergence and watered into the soil the next day. Subsurface banded ESN (ESNssb) and check (no N applied) treatments were included. Nitrous oxide fluxes were measured during two growing seasons and after harvest using static, vented chambers. All N sources had significantly lower growing-season NO emissions than granular urea (0.7% of applied N), with UAN+AgrotainPlus (0.2% of applied N) and ESN (0.3% of applied N) having lower emissions than UAN (0.4% of applied N). Similar trends were observed when expressing NO emissions on a grain yield and N uptake basis. Corn grain yields were not different among N sources but were greater than the check. Selection of N fertilizer source can be a mitigation practice for reducing NO emissions in NT, irrigated corn in semiarid areas. In our study, UAN+AgrotainPlus consistently had the lowest level of NO emissions with no yield loss. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  15. A Comparative Study of the Application of Fluorescence Excitation-Emission Matrices Combined with Parallel Factor Analysis and Nonnegative Matrix Factorization in the Analysis of Zn Complexation by Humic Acids

    Directory of Open Access Journals (Sweden)

    Patrycja Boguta

    2016-10-01

    Full Text Available The main aim of this study was the application of excitation-emission fluorescence matrices (EEMs combined with two decomposition methods: parallel factor analysis (PARAFAC and nonnegative matrix factorization (NMF to study the interaction mechanisms between humic acids (HAs and Zn(II over a wide concentration range (0–50 mg·dm−3. The influence of HA properties on Zn(II complexation was also investigated. Stability constants, quenching degree and complexation capacity were estimated for binding sites found in raw EEM, EEM-PARAFAC and EEM-NMF data using mathematical models. A combination of EEM fluorescence analysis with one of the proposed decomposition methods enabled separation of overlapping binding sites and yielded more accurate calculations of the binding parameters. PARAFAC and NMF processing allowed finding binding sites invisible in a few raw EEM datasets as well as finding totally new maxima attributed to structures of the lowest humification. Decomposed data showed an increase in Zn complexation with an increase in humification, aromaticity and molecular weight of HAs. EEM-PARAFAC analysis also revealed that the most stable compounds were formed by structures containing the highest amounts of nitrogen. The content of oxygen-functional groups did not influence the binding parameters, mainly due to fact of higher competition of metal cation with protons. EEM spectra coupled with NMF and especially PARAFAC processing gave more adequate assessments of interactions as compared to raw EEM data and should be especially recommended for modeling of complexation processes where the fluorescence intensities (FI changes are weak or where the processes are interfered with by the presence of other fluorophores.

  16. Influence of field emission on the propagation of cylindrical fast ionization wave in atmospheric-pressure nitrogen

    Energy Technology Data Exchange (ETDEWEB)

    Levko, Dmitry; Raja, Laxminarayan L. [Department of Aerospace Engineering and Engineering Mechanics, The University of Texas at Austin, Austin, Texas 78712 (United States)

    2016-04-21

    The influence of field emission of electrons from surfaces on the fast ionization wave (FIW) propagation in high-voltage nanosecond pulse discharge in the atmospheric-pressure nitrogen is studied by a one-dimensional Particle-in-Cell Monte Carlo Collisions model. A strong influence of field emission on the FIW dynamics and plasma parameters is obtained. Namely, the accounting for the field emission makes possible the bridging of the cathode–anode gap by rather dense plasma (∼10{sup 13 }cm{sup −3}) in less than 1 ns. This is explained by the generation of runaway electrons from the field emitted electrons. These electrons are able to cross the entire gap pre-ionizing it and promoting the ionization wave propagation. We have found that the propagation of runaway electrons through the gap cannot be accompanied by the streamer propagation, because the runaway electrons align the plasma density gradients. In addition, we have obtained that the field enhancement factor allows controlling the speed of ionization wave propagation.

  17. Cu2 + modulated nitrogen-doped grapheme quantum dots as a turn-off/on fluorescence sensor for the selective detection of histidine in biological fluid

    Science.gov (United States)

    Wang, Zhiyu; Fan, ZheFeng

    2018-01-01

    A highly sensitive sensor for detection of histidine (His) based on the nitrogen-doped graphene quantum dots (N-GQDs)-Cu2 + system has been designed. The N-GQDs were synthesized by one-step hydrothermal approach according to previous report. The fluorescence of N-GQDs can be effectively quenched by Cu2 + due to the binding between Cu2 + and functional groups on the surface of N-GQDs. The high affinity of His to Cu2 + enables Cu2 + to be dissociated from the surface of N-GQDs and recovering the fluorescence. The sensor displayed a sensitive response to His in the concentration range of 0-35 μmol L- 1, with a detection limit of 72.2 nmol L- 1. The proposed method is successfully applied to detect His in samples with a recovery range of 96-102%.

  18. Nitrogen emission balance for Niedersachsen; Bilanzierung der Stickstoffemissionen in Niedersachsen

    Energy Technology Data Exchange (ETDEWEB)

    Krieg, V.

    2000-07-01

    This report provides a comprehensive emission balance for the German state of Niedersachsen, which will provide a basis for deciding on actions to reduce nitrogen levels. [German] In einem natuerlichen Oekosystem erfolgt der Grossteil des Stickstoffumsatzes als Kreisprozess, aus dem nur verhaeltnismaessig geringe Mengen in das System importiert bzw. aus dem System exportiert werden. Durch menschliche Nutzungsaktivitaeten wie insbesondere im landwirtschaftlichen Bereich sowie durch atmosphaerische Eintraege wird dieser natuerliche Kreislauf stark beeintraechtigt. In der Regel kann in den dicht besiedelten industriell gepraegten und landwirtschaftlich intensiv genutzten Regionen Europas von einem deutlichen Stickstoffueberschuss ausgegangen werden mit den negativen Folgen von Boden- und Gewaesserbelastung und den Eutrophierungserscheinungen bei aquatischen und terrestrischen Oekosystemen. Der dringende Handlungsbedarf zur Senkung der menschlich verursachten Stickstoffueberschuesse ist offensichtlich und in einem Bericht der Arbeitsgruppe aus Vertretern der Umwelt- und Agrarministerkonferenz (STICKSTOFFMINDERUNGSPROGRAMM, 1997) dokumentiert. Grundlage fuer entsprechende Massnahmen muss der Nachweis der entsprechenden Emissionsquellen unter Beruecksichtigung von wechselseitigen Beeinflussungen sein. Der vorliegende Bericht liefert fuer das Bundesland Niedersachsen eine vollstaendige Bilanzierung und damit eine fundierte Basis fuer entsprechende Handlungsempfehlungen zur Reduzierung des Stickstoffniveaus. (orig.)

  19. 76 FR 29180 - Approval and Promulgation of Air Quality Implementation Plans; Pennsylvania; Control of Nitrogen...

    Science.gov (United States)

    2011-05-20

    ... Promulgation of Air Quality Implementation Plans; Pennsylvania; Control of Nitrogen Oxides Emissions From... Pennsylvania. This revision pertains to the control of nitrogen oxide (NO X ) emissions from Portland cement... oxidation of chemically-bound nitrogen in the fuel and by thermal fixation of nitrogen in the combustion air...

  20. The long-term impact of urbanization on nitrogen patterns and dynamics in Shanghai, China

    International Nuclear Information System (INIS)

    Gu Baojing; Dong Xiaoli; Peng Changhui; Luo Weidong; Chang Jie; Ge Ying

    2012-01-01

    Urbanization is an important process that alters the regional and global nitrogen biogeochemistry. In this study, we test how long-term urbanization (1952–2004) affects the nitrogen flows, emissions and drivers in the Greater Shanghai Area (GSA) based on the coupled human and natural systems (CHANS) approach. Results show that: (1) total nitrogen input to the GSA increased from 57.7 to 587.9 Gg N yr −1 during the period 1952–2004, mainly attributing to fossil fuel combustion (43%), Haber–Bosch nitrogen fixation (31%), and food/feed import (26%); (2) per capita nitrogen input increased from 13.5 to 45.7 kg N yr −1 , while per gross domestic product (GDP) nitrogen input reduced from 22.2 to 0.9 g N per Chinese Yuan, decoupling of nitrogen with GDP; (3) emissions of reactive nitrogen to the environment transformed from agriculture dominated to industry and human living dominated, especially for air pollution. This study provides decision-makers a novel view of nitrogen management. - Highlights: ► Major Nr emission source shifts from agriculture to industry alongside urbanization. ► Decoupling of nitrogen with GDP and urban expansion arises alongside urbanization. ► Nitrogen fluxes increase with population growth and living standard promotion. - Major nitrogen emission source shifts from agriculture to industry and human, and decoupling of nitrogen with GDP and urban expansion arises alongside urbanization.

  1. Enhanced localized fluorescence in plasmonic nanoantennae

    DEFF Research Database (Denmark)

    Bakker, R.M.; Yuan, H.-K.; Liu, Z.

    2008-01-01

    in fluorescence that reaches 100 times enhancement. Near-field excitation shows enhanced fluorescence from a single nanoantenna localized in a subwavelength area of similar to 0.15 mu m(2). The polarization of enhanced emission is along the main antenna axis. These observed experimental results are important...

  2. Fluorescence lifetime imaging of skin cancer

    Science.gov (United States)

    Patalay, Rakesh; Talbot, Clifford; Munro, Ian; Breunig, Hans Georg; König, Karsten; Alexandrov, Yuri; Warren, Sean; Neil, Mark A. A.; French, Paul M. W.; Chu, Anthony; Stamp, Gordon W.; Dunsby, Chris

    2011-03-01

    Fluorescence intensity imaging and fluorescence lifetime imaging microscopy (FLIM) using two photon microscopy (TPM) have been used to study tissue autofluorescence in ex vivo skin cancer samples. A commercially available system (DermaInspect®) was modified to collect fluorescence intensity and lifetimes in two spectral channels using time correlated single photon counting and depth-resolved steady state measurements of the fluorescence emission spectrum. Uniquely, image segmentation has been used to allow fluorescence lifetimes to be calculated for each cell. An analysis of lifetime values obtained from a range of pigmented and non-pigmented lesions will be presented.

  3. A novel fluorescence probe based on triphenylamine Schiff base for bioimaging and responding to pH and Fe3+

    International Nuclear Information System (INIS)

    Wang, Lei; Yang, Xiaodong; Chen, Xiuli; Zhou, Yuping; Lu, Xiaodan; Yan, Chenggong; Xu, Yikai; Liu, Ruiyuan; Qu, Jinqing

    2017-01-01

    A novel fluorescence probe 1 based on triphenylamine was synthesized and characterized by NMR, IR, high resolution mass spectrometry and elemental analysis. Its fluorescence was quenched when pH below 2. There was a linear relationship between the fluorescence intensity and pH value ranged from 2 to 7. And its fluorescence emission was reversibility in acidic and alkaline solution. Furthermore, it exhibited remarkable selectivity and high sensitivity to Fe 3+ and was able to detect Fe 3+ in aqueous solution with low detection limit of 0.511 μM. Job plot showed that the binding stoichiometry of 1 with Fe 3+ was 1:1. Further observations of 1 H NMR titration suggested that coordination interaction between Fe 3+ and nitrogen atom on C =N bond promoted the intramolecular charge transfer (ICT) or energy transfer process causing fluorescence quenching. Additionally, 1 was also able to be applied for detecting Fe 3+ in living cell and bioimaging. - Graphical abstract: Triphenylamine based fluorescence probe can detect pH and Fe 3+ simultaneously in aqueous solution and be applied for detecting Fe 3+ in living cell and bioimaging. - Highlights: • The fluorescence probe is sensitive to pH in strong acid conditions. • The fluorescence chemosensor can detect pH and Fe 3+ simultaneously. • The recognition is able to carry out in aqueous solution. • The probe can also be applied for detecting Fe 3+ in living cell and bioimaging. • The sensor is synthesized easily with one step.

  4. Characterizing the transformation and transfer of nitrogen during the aerobic treatment of organic wastes and digestates

    Energy Technology Data Exchange (ETDEWEB)

    Zeng Yang, E-mail: yang.zeng@irstea.fr [Irstea, UR GERE, 17 avenue de Cucille, CS 64427, F-35044 Rennes Cedex (France); Universite Europeenne de Bretagne, F-35000 Rennes (France); Guardia, Amaury de; Daumoin, Mylene; Benoist, Jean-Claude [Irstea, UR GERE, 17 avenue de Cucille, CS 64427, F-35044 Rennes Cedex (France)

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer Ammonia emissions varied depending on the nature of wastes and the treatment conditions. Black-Right-Pointing-Pointer Nitrogen losses resulted from ammonia emissions and nitrification-denitrification. Black-Right-Pointing-Pointer Ammonification can be estimated from biodegradable carbon and carbon/nitrogen ratio. Black-Right-Pointing-Pointer Ammonification was the main process contributing to N losses. Black-Right-Pointing-Pointer Nitrification rate was negatively correlated to stripping rate of ammonia nitrogen. - Abstract: The transformation and transfer of nitrogen during the aerobic treatment of seven wastes were studied in ventilated air-tight 10-L reactors at 35 Degree-Sign C. Studied wastes included distinct types of organic wastes and their digestates. Ammonia emissions varied depending on the kind of waste and treatment conditions. These emissions accounted for 2-43% of the initial nitrogen. Total nitrogen losses, which resulted mainly from ammonia emissions and nitrification-denitrification, accounted for 1-76% of the initial nitrogen. Ammonification was the main process responsible for nitrogen losses. An equation which allows estimating the ammonification flow of each type of waste according to its biodegradable carbon and carbon/nitrogen ratio was proposed. As a consequence of the lower contribution of storage and leachate rates, stripping and nitrification rates of ammonia nitrogen were negatively correlated. This observation suggests the possibility of promotingnitrification in order to reduce ammonia emissions.

  5. Effect of nitrogen fertilization and residue management practices on ammonia emissions from subtropical sugarcane production

    Science.gov (United States)

    mudi, Sanku Datta; Wang, Jim J.; Dodla, Syam Kumar; Arceneaux, Allen; Viator, H. P.

    2016-08-01

    Ammonia (NH3) emission from soil is a loss of nitrogen (N) nutrient for plant production as well as an issue of air quality, due to the fact that it is an active precursor of airborne particulate matters. Ammonia also acts as a secondary source of nitrous oxide (N2O) emission when present in the soil. In this study, the impacts of different sources of N fertilizers and harvest residue management schemes on NH3 emissions from sugarcane production were evaluated based on an active chamber method. The field experiment plots consisting of two sources of N fertilizer (urea and urea ammonium nitrate (UAN)) and two common residue management practices, namely residue retained (RR) and residue burned (RB), were established on a Commerce silt loam. The NH3 volatilized following N fertilizer application was collected in an impinger containing diluted citric acid and was subsequently analyzed using ion chromatography. The NH3 loss was primarily found within 3-4 weeks after N application. Average seasonal soil NH3 flux was significantly greater in urea plots with NH3-N emission factor (EF) twice or more than in UAN plots (2.4-5.6% vs. 1.2-1.7%). The RR residue management scheme had much higher NH3 volatilization than the RB treatment regardless of N fertilizer sources, corresponding to generally higher soil moisture levels in the former. Ammonia-N emissions in N fertilizer-treated sugarcane fields increased with increasing soil water-filled pore space (WFPS) up to 45-55% observed in the field. Both N fertilizer sources and residue management approaches significantly affected NH3 emissions.

  6. Contribution of nitrogen oxide and sulfur dioxide exposure from power plant emissions on respiratory symptom and disease prevalence

    International Nuclear Information System (INIS)

    Amster, Eric D.; Haim, Maayan; Dubnov, Jonathan; Broday, David M.

    2014-01-01

    This study investigates the association between exposure to ambient NO x and SO 2 originating from power plant emissions and prevalence of obstructive pulmonary disease and related symptoms. The Orot Rabin coal-fired power plant is the largest power generating facility in the Eastern Mediterranean. Two novel methods assessing exposure to power plant-specific emissions were estimated for 2244 participants who completed the European Community Respiratory Health Survey. The “source approach” modeled emissions traced back to the power plant while the “event approach” identified peak exposures from power plant plume events. Respiratory symptoms, but not prevalence of asthma and COPD, were associated with estimates of power plant NO x emissions. The “source approach” yielded a better estimate of exposure to power plant emissions and showed a stronger dose–response relationship with outcomes. Calculating the portion of ambient pollution attributed to power plants emissions can be useful for air quality management purposes and targeted abatement programs. -- Highlights: • Two methods assessing NO x and SO 2 exposure attributed to a coal-fired power plant are utilized. • Exposure estimates are compared with respiratory outcomes in 2244 participants. • Power plant nitrogen oxide emissions are associated with respiratory symptoms. • Stack emission models correlated closest with health outcomes. -- Chronic cough, nocturnal dyspnea, chronic phlegm, and shortness of breath were significantly associated with exposure estimates of power plant-specific NO x emissions

  7. 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

  8. An assessment of the real-world driving gaseous emissions from a Euro 6 light-duty diesel vehicle using a portable emissions measurement system (PEMS)

    Science.gov (United States)

    Luján, José M.; Bermúdez, Vicente; Dolz, Vicente; Monsalve-Serrano, Javier

    2018-02-01

    Recent investigations demonstrated that real-world emissions usually exceed the levels achieved in the laboratory based type approval processes. By means of on-board emissions measurements, it has been shown that nitrogen oxides emitted by diesel engines substantially exceed the limit imposed by the Euro 6 regulation. Thus, with the aim of complementing the worldwide harmonized light vehicles test cycle, the real driving emissions cycle will be introduced after 1 September 2017 to regulate the vehicle emissions in real-world driving situations. This paper presents on-board gaseous emissions measurements from a Euro 6 light-duty diesel vehicle in a real-world driving route using a portable emissions measurement system. The test route characteristics follow the requirements imposed by the RDE regulation. The analysis of the raw emissions results suggests that the greatest amount of nitrogen oxides and nitrogen dioxide are emitted during the urban section of the test route, confirming that lower speeds with more accelerations and decelerations lead to higher nitrogen oxides emissions levels than constant high speeds. Moreover, the comparison of the two calculation methods proposed by the real driving emissions regulation has revealed emissions rates differences ranging from 10% to 45% depending on the pollutant emission and the trip section considered (urban or total). Thus, the nitrogen oxides emissions conformity factor slightly varies from one method to the other.

  9. Fluorescence spectroscopy and multi-way techniques. PARAFAC

    DEFF Research Database (Denmark)

    Murphy, Kathleen R.; Stedmon, Colin A.; Graeber, Daniel

    2013-01-01

    PARAllel FACtor analysis (PARAFAC) is increasingly used to decompose fluorescence excitation emission matrices (EEMs) into their underlying chemical components. In the ideal case where fluorescence conforms to Beers Law, this process can lead to the mathematical identification and quantification...

  10. Nitrification inhibitors mitigated reactive gaseous nitrogen intensity in intensive vegetable soils from China.

    Science.gov (United States)

    Fan, Changhua; Li, Bo; Xiong, Zhengqin

    2018-01-15

    Nitrification inhibitors, a promising tool for reducing nitrous oxide (N 2 O) losses and promoting nitrogen use efficiency by slowing nitrification, have gained extensive attention worldwide. However, there have been few attempts to explore the broad responses of multiple reactive gaseous nitrogen emissions of N 2 O, nitric oxide (NO) and ammonia (NH 3 ) and vegetable yield to nitrification inhibitor applications across intensive vegetable soils in China. A greenhouse pot experiment with five consecutive vegetable crops was performed to assess the efficacies of two nitrification inhibitors, namely, nitrapyrin and dicyandiamide on reactive gaseous nitrogen emissions, vegetable yield and reactive gaseous nitrogen intensity in four typical vegetable soils representing the intensive vegetable cropping systems across mainland China: an Acrisol from Hunan Province, an Anthrosol from Shanxi Province, a Cambisol from Shandong Province and a Phaeozem from Heilongjiang Province. The results showed soil type had significant influences on reactive gaseous nitrogen intensity, with reactive gaseous nitrogen emissions and yield mainly driven by soil factors: pH, nitrate, C:N ratio, cation exchange capacity and microbial biomass carbon. The highest reactive gaseous nitrogen emissions and reactive gaseous nitrogen intensity were in Acrisol while the highest vegetable yield occurred in Phaeozem. Nitrification inhibitor applications decreased N 2 O and NO emissions by 1.8-61.0% and 0.8-79.5%, respectively, but promoted NH 3 volatilization by 3.2-44.6% across all soils. Furthermore, significant positive correlations were observed between inhibited N 2 O+NO and stimulated NH 3 emissions with nitrification inhibitor additions across all soils, indicating that reduced nitrification posed the threat of NH 3 losses. Additionally, reactive gaseous nitrogen intensity was significantly reduced in the Anthrosol and Cambisol due to the reduced reactive gaseous nitrogen emissions and increased

  11. Space based inverse modeling of seasonal variations of anthropogenic and natural emissions of nitrogen oxides over China and effects of uncertainties in model meteorology and chemistry

    Science.gov (United States)

    Lin, J.

    2011-12-01

    Nitrogen oxides (NOx ≡ NO + NO2) are important atmospheric constituents affecting the tropospheric chemistry, surface air quality and climatic forcing. They are emitted both from anthropogenic and from natural (soil, lightning, biomass burning, etc.) sources, which can be estimated inversely from satellite remote sensing of the vertical column densities (VCDs) of nitrogen dioxide (NO2) in the troposphere. Based on VCDs of NO2 retrieved from OMI, a novel approach is developed in this study to separate anthropogenic emissions of NOx from natural sources over East China for 2006. It exploits the fact that anthropogenic and natural emissions vary with seasons with distinctive patterns. The global chemical transport model (CTM) GEOS-Chem is used to establish the relationship between VCDs of NO2 and emissions of NOx for individual sources. Derived soil emissions are compared to results from a newly developed bottom-up approach. Effects of uncertainties in model meteorology and chemistry over China, an important source of errors in the emission inversion, are evaluated systematically for the first time. Meteorological measurements from space and the ground are used to analyze errors in meteorological parameters driving the CTM.

  12. Red organic light emitting devices with reduced efficiency roll-off behavior by using hybrid fluorescent/phosphorescent emission structure

    Energy Technology Data Exchange (ETDEWEB)

    Zheng Tianhang; Choy, Wallace C.H., E-mail: chchoy@eee.hku.h

    2010-11-01

    Organic light emitting device (OLED) with a fluorescence-interlayer-phosphorescence emissive structure (FIP EML) is proposed to solve efficiency roll-off issue effectively. By doping fluorescent emitter of 4-(dicyanomethylene)-2-t-butyl-6-(1,1,7,7-tetramethyljulolidyl-9-enyl) -4H-pyran (DCJTB) and phosphorescent emitter of tris(1-phenylisoquinolinolato-C2,N)iridium(III) (Ir(piq){sub 3}) into the different regions of emission zone to form FIP EML in red OLED, an improvement of more than 20% in luminance efficiency roll-off compared with that of typical phosphorescent OLED with single EML in 10-500 mA/cm{sup 2} range has been obtained. Detailed mechanisms have been studied. Such improvement should be attributed to the distinct roles of the two emitters, where DCJTB mainly used to influence the carrier transport leading to an improved balance of charge carriers while Ir(piq){sub 3} functions as the radiative decay sites for most generated excitons. Meanwhile, with the help of the formation of FIP EML, the redistribution of excitons in recombination zone, the suppression of non-radiative exciton quenching processes and the elimination of energy transfer loss also contribute to the enhancement of efficiency roll-off. The method proposed here may provide a route to develop efficient OLED for high luminance applications.

  13. Multimodality Imaging Probe for Positron Emission Tomography and Fluorescence Imaging Studies

    Directory of Open Access Journals (Sweden)

    Suresh K. Pandey

    2014-05-01

    Full Text Available Our goal is to develop multimodality imaging agents for use in cell tracking studies by positron emission tomography (PET and optical imaging (OI. For this purpose, bovine serum albumin (BSA was complexed with biotin (histologic studies, 5(6- carboxyfluorescein, succinimidyl ester (FAM SE (OI studies, and diethylenetriamine pentaacetic acid (DTPA for chelating gallium 68 (PET studies. For synthesis of BSA-biotin-FAM-DTPA, BSA was coupled to (+-biotin N-hydroxysuccinimide ester (biotin-NHSI. BSA- biotin was treated with DTPA-anhydride and biotin-BSA-DTPA was reacted with FAM. The biotin-BSA-DTPA-FAM was reacted with gallium chloride 3 to 5 mCi eluted from the generator using 0.1 N HCl and was passed through basic resin (AG 11 A8 and 150 mCi (100 μL, pH 7–8 was incubated with 0.1 mg of FAM conjugate (100 μL at room temperature for 15 minutes to give 66Ga-BSA-biotin-DTPA-FAM. A shaved C57 black mouse was injected with FAM conjugate (50 μL at one flank and FAM-68Ga (50 μL, 30 mCi at the other. Immediately after injection, the mouse was placed in a fluorescence imaging system (Kodak In-Vivo F, Bruker Biospin Co., Woodbridge, CT and imaged (Λex: 465 nm, Λem: 535 nm, time: 8 seconds, Xenon Light Source, Kodak. The same mouse was then placed under an Inveon microPET scanner (Siemens Medical Solutions, Knoxville, TN injected (intravenously with 25 μCi of 18F and after a half-hour (to allow sufficient bone uptake was imaged for 30 minutes. Molecular weight determined using matrix-associated laser desorption ionization (MALDI for the BSA sample was 66,485 Da and for biotin-BSA was 67,116 Da, indicating two biotin moieties per BSA molecule; for biotin-BSA-DTPA was 81,584 Da, indicating an average of 30 DTPA moieties per BSA molecule; and for FAM conjugate was 82,383 Da, indicating an average of 1.7 fluorescent moieties per BSA molecule. Fluorescence imaging clearly showed localization of FAM conjugate and FAM-68Ga at respective flanks of the mouse

  14. Impact of warming, moderate nitrogen addition and bark herbivory on BVOC emissions and growth of Scots pine (Pinus sylvestris L.) seedlings.

    Science.gov (United States)

    Tiiva, Päivi; Häikiö, Elina; Kasurinen, Anne

    2018-04-10

    The changing climate will expose boreal forests to rising temperatures, increasing soil nitrogen (N) levels and an increasing risk of herbivory. The single and interaction effects of warming (+2 °C increase), moderate N addition (30 kg ha-1 year-1) and bark herbivory by large pine weevil (Hylobius abietis L.) on growth and emissions of biogenic volatile organic compounds (BVOCs) from shoots of Scots pine (Pinus sylvestris L.) seedlings were studied in growth chambers over 175 days. In addition, warming and N addition effects on shoot net photosynthesis (Pn) were measured. Nitrogen addition increased both shoot and root dry weights, whereas warming, in combination with herbivory, reduced stem height growth. Warming together with N addition increased current-year shoot Pn, whereas N effects on previous-year shoot Pn were variable over time. Warming decreased non-oxygenated monoterpene (MT) emissions in June and increased them in July. Of individual MT compounds, α-pinene, δ-3-carene, γ-terpinene and terpinolene were among the most frequently responsive compounds in warming treatments in the May-July period. Sesquiterpene emissions were observed only from warming treatments in July. Moderate N addition increased oxygenated monoterpenes in May, and MTs in June and September. However, N addition effect on MTs in June was clearer without warming than with warming. Bark herbivory tended to increase MT emissions in combination with warming and N addition 3 weeks after the damage caused by weevils. Of individual compounds in other BVOC blends, herbivory increased the emissions of methyl-benzene, benzene and hexanal in July. Hence, though both warming and N addition have a potential to change BVOC emissions from Scots pines, the N effect may also be partly cancelled by warming. Furthermore, herbivory pressure in combination with climate warming and N addition may, at least periodically, increase BVOC release to the atmosphere from young Scots pine seedlings.

  15. DNA-Based Self-Assembly of Fluorescent Nanodiamonds.

    Science.gov (United States)

    Zhang, Tao; Neumann, Andre; Lindlau, Jessica; Wu, Yuzhou; Pramanik, Goutam; Naydenov, Boris; Jelezko, Fedor; Schüder, Florian; Huber, Sebastian; Huber, Marinus; Stehr, Florian; Högele, Alexander; Weil, Tanja; Liedl, Tim

    2015-08-12

    As a step toward deterministic and scalable assembly of ordered spin arrays we here demonstrate a bottom-up approach to position fluorescent nanodiamonds (NDs) with nanometer precision on DNA origami structures. We have realized a reliable and broadly applicable surface modification strategy that results in DNA-functionalized and perfectly dispersed NDs that were then self-assembled in predefined geometries. With optical studies we show that the fluorescence properties of the nitrogen-vacancy color centers in NDs are preserved during surface modification and DNA assembly. As this method allows the nanoscale arrangement of fluorescent NDs together with other optically active components in complex geometries, applications based on self-assembled spin lattices or plasmon-enhanced spin sensors as well as improved fluorescent labeling for bioimaging could be envisioned.

  16. Effect of irrigation, nitrogen application, and a nitrification inhibitor on nitrous oxide, carbon dioxide and methane emissions from an olive (Olea europaea L.) orchard

    Energy Technology Data Exchange (ETDEWEB)

    Maris, S.C., E-mail: stefania@macs.udl.cat [University of Lleida, Environment and Soil Science Department, Av. Alcalde Rovira Roure 191, E-25198 Lleida (Spain); Teira-Esmatges, M.R. [University of Lleida, Environment and Soil Science Department, Av. Alcalde Rovira Roure 191, E-25198 Lleida (Spain); Arbonés, A.; Rufat, J. [Programa Ús Eficient de l’Aigua, Institut de Recerca i Tecnologia Agroalimentàries (IRTA), Parc Científic i Tecnològic Agroalimentari de Lleida (PCiTAL). Parc de Gardeny, Edifici Fruitcentre, E-2503 Lleida (Spain)

    2015-12-15

    Drip irrigation combined with nitrogen (N) fertigation is applied in order to save water and improve nutrient efficiency. Nitrification inhibitors reduce greenhouse gas emissions. A field study was conducted to compare the emissions of nitrous oxide (N{sub 2}O), carbon dioxide (CO{sub 2}) and methane (CH{sub 4}) associated with the application of N fertiliser through fertigation (0 and 50 kg N ha{sup −1}), and 50 kg N ha{sup −1} + nitrification inhibitor in a high tree density Arbequina olive orchard. Spanish Arbequina is the most suited variety for super intensive olive groves. This system allows reducing production costs and increases crop yield. Moreover its oil has excellent sensorial features. Subsurface drip irrigation markedly reduced N{sub 2}O and N{sub 2}O + N{sub 2} emissions compared with surface drip irrigation. Fertiliser application significantly increased N{sub 2}O + N{sub 2}, but not N{sub 2}O emissions. Denitrification was the main source of N{sub 2}O. The N{sub 2}O losses (calculated as emission factor) ranging from − 0.03 to 0.14% of the N applied, were lower than the IPCC (2007) values. The N{sub 2}O + N{sub 2} losses were the largest, equivalent to 1.80% of the N applied, from the 50 kg N ha{sup −1} + drip irrigation treatment which resulted in water filled pore space > 60% most of the time (high moisture). Nitrogen fertilisation significantly reduced CO{sub 2} emissions in 2011, but only for the subsurface drip irrigation strategies in 2012. The olive orchard acted as a net CH{sub 4} sink for all the treatments. Applying a nitrification inhibitor (DMPP), the cumulative N{sub 2}O and N{sub 2}O + N{sub 2} emissions were significantly reduced with respect to the control. The DMPP also inhibited CO{sub 2} emissions and significantly increased CH{sub 4} oxidation. Considering global warming potential, greenhouse gas intensity, cumulative N{sub 2}O emissions and oil production, it can be concluded that applying DMPP with 50 kg N ha{sup −1

  17. Hybrid fluorescent nanoparticles fabricated from pyridine-functionalized polyfluorene-based conjugated polymer as reversible pH probes over a broad range of acidity-alkalinity

    International Nuclear Information System (INIS)

    Cui, Haijun; Chen, Ying; Li, Lianshan; Tang, Zhiyong; Wu, Yishi; Fu, Hongbing; Tian, Zhiyuan

    2014-01-01

    Conjugated polymer nanoparticles (CPNs) were developed based on a polyfluorene-based conjugated polymer with thiophene units carrying pyridyl moieties incorporated in the backbone of polymer chains (PFPyT). Hybrid CPNs fabricated from PFPyT and an amphiphilic polymer (NP1) displayed pH-sensitive fluorescence emission features in the range from pH 4.8 to 13, which makes them an attractive nanomaterial for wide range optical sensing of pH values. The fluorescence of hybrid CPNs based on chemically close polyfluorene derivatives without pyridyl moieties (NP3), in contrast, remains virtually unperturbed by pH values in the same range. The fluorescence emission features of NP1 underwent fully reversible changes upon alternating acidification/basification of aqueous dispersions of the CPNs and also displayed excellent repeatability. The observed pH sensing properties of NP1 are attributed to protonation/deprotonation of the nitrogen atoms of the pyridine moieties. This, in turn, leads to the redistribution of electron density of pyridine moieties and their participation in the π-conjugation within the polymer main chains. The optically transparent amphiphilic polymers also exerted significant influence on the pH sensing features of the CPNs, likely by acting as proton sponge and/or acid chaperone. (author)

  18. Experimental and theoretical study on emission spectra of a nitrogen photoionized plasma induced by intense EUV pulses

    Science.gov (United States)

    Saber, Ismail; Bartnik, Andrzej; Skrzeczanowski, Wojciech; Wachulak, Przemyslaw; Jarocki, Roman; Fiedorowicz, Henryk; Limpouch, Jiri

    2018-01-01

    Spectral lines of low-temperature nitrogen photoionized plasma were investigated. The photoionized plasma was created in the result of irradiation N2 gas using laser plasma EUV radiation pulses. The source was based on a 10J/10ns Nd:YAG (λ = 1064 nm) laser system and a gas puff target. The EUV radiation pulses were collected and focused using a grazing incidence multifoil EUV collector. The emission spectra were measured in the ultraviolet and visible (UV/Vis) range. It was found that the plasma emission lines in the lower region of the UV range are relativley weak. Nonetheless, a part of the spectra contains strong molecular band in the 300 - 430 nm originated from second positive and first negative systems band transitions of nitrogen. These molecular band transitions were identified using a code for study the diatomic molecules, LIFBASE. The vibrational band of Δv = 0 and ±1 transitions were significantly populated than of that with Δv = ±2 and 3 transitions. A comparison of the calculated and measured spectrum is presented. With an assumption of a local thermodynamic equilibrium (LTE), the vibrational temperature was determined from the integrated band intensities with the help of the Boltzmann plot method and compared to the temperature predicted by SPECAIR and LIFBASE simulations. A summary of the results and the variations in the vibrational temperatures was discussed.

  19. Experimental and theoretical study on emission spectra of a nitrogen photoionized plasma induced by intense EUV pulses

    Directory of Open Access Journals (Sweden)

    Saber Ismail

    2018-01-01

    Full Text Available Spectral lines of low-temperature nitrogen photoionized plasma were investigated. The photoionized plasma was created in the result of irradiation N2 gas using laser plasma EUV radiation pulses. The source was based on a 10J/10ns Nd:YAG (λ = 1064 nm laser system and a gas puff target. The EUV radiation pulses were collected and focused using a grazing incidence multifoil EUV collector. The emission spectra were measured in the ultraviolet and visible (UV/Vis range. It was found that the plasma emission lines in the lower region of the UV range are relativley weak. Nonetheless, a part of the spectra contains strong molecular band in the 300 - 430 nm originated from second positive and first negative systems band transitions of nitrogen. These molecular band transitions were identified using a code for study the diatomic molecules, LIFBASE. The vibrational band of Δv = 0 and ±1 transitions were significantly populated than of that with Δv = ±2 and 3 transitions. A comparison of the calculated and measured spectrum is presented. With an assumption of a local thermodynamic equilibrium (LTE, the vibrational temperature was determined from the integrated band intensities with the help of the Boltzmann plot method and compared to the temperature predicted by SPECAIR and LIFBASE simulations. A summary of the results and the variations in the vibrational temperatures was discussed.

  20. Nitrogen oxides from combustion of nitrogen-containing polymers in waste-derived fuels

    International Nuclear Information System (INIS)

    Zevenhoven, R.; Kilpinen, P.; Hupa, M.; Elomaa, M.

    2000-01-01

    Usually, waste-derived fuels present nitrogen-containing fractions, which produce nitrogen oxides (NO) during combustion. This study was mainly concerned with poly amides (PA) (nylon), poly urethanes (PU), urea formaldehyde (UF) glue, sewage sludge and refuse-derived fuels (RDF). For control purposes, the authors chose a Polish sub-bituminous coal and a Finnish pine wood sample. An almost inverse trend between fuel nitrogen content and NO emissions was revealed through analysis of NO emissions at 850 Celsius, 1 bar, 7 per cent O 2 in N 2 . It was not possible to derive a clear correlation to the amount of ash generated by the samples. PU foam decomposed through a two-step process, as suggested by thermochromatography, and PA6-containing samples yielded epsilon-caprolactam as a major decomposition product. Important decomposition products from PU, PA6, PA6/PE, sewage sludge and UF glue samples were greenhouse gases as demonstrated by pyrolysis-gas chromatography/mass spectroscopy. The work was carried out at Abo Akademi University and University of Helsinki, Finland. 5 refs., 2 tabs., 3 figs

  1. Ratiometric fluorescent nanosensor based on carbon dots for the detection of mercury ion

    Science.gov (United States)

    Ma, Yusha; Mei, Jing; Bai, Jianliang; Chen, Xu; Ren, Lili

    2018-05-01

    A novel ratiometric fluorescent nanosensor based on carbon dots has been synthesized via bonding rhodamine B hydrazide to the carbon dots surface by an amide reaction. The ratiometric fluorescent nanosensor showed only a single blue fluorescence emission around 450 nm. While, as mercury ion was added, due to the open-ring of rhodamine moiety bonded on the CDs surface, the orange emission of the open-ring rhodamine would increase obviously according to the concentration of mercury ion, resulting in the distinguishable dual emissions at 450 nm and 575 nm under a single 360 excitation wavelength. Meanwhile, the ratiometric fluorescent nanosensor based on carbon dots we prepared is more sensitive to qualitative and semi-quantitative detection of mercury ion in the range of 0–100 μM, because fluorescence changes gradually from blue to orange emission under 365 nm lamp with the increasing of mercury ion in the tested solution.

  2. Emissions of nitrogen oxides from road traffic - regulations, emissions and effects

    International Nuclear Information System (INIS)

    Sjoedin, Aake; Pihl-Karlsson, Gunilla; Johansson, Manne; Forsberg, Bertil; Erlandsson, Lennart

    2004-10-01

    The report is a review that aims to improve the basis for additional measures against the road traffic emissions of, in particular, NO x . An important question in the context is whether health effects of NO 2 should serve as a norm for the actions for emission reductions of NO x , or if the environmental effects of NO x -emissions in the form of acidification, eutrophication and ozone should play this role. WHO notes, in its latest review of health effect research, that one cannot demonstrate that NO 2 alone has any direct effects in concentrations at the current whole-year mean norm (40 μg/m 3 ). Such health effects that has been demonstrated in epidemiologic studies at these concentrations are caused by other traffic related emissions (e. g. particles) for which NO 2 constitutes a good indicator. WHO indicates the need for additional sharpening of the norms for ozone and particles. In this context, it is important to note that emissions of NO x on a regional scale contributes to formation of ozone as well as particles. Therefore there exist reasons to decrease the emissions of NO x in order to reach future recommended values for ozone and particles emissions. In the evaluations that will be done during 2004-2005 of the so called Goeteborg protocol, the EU's Ceiling Directives and the CAFE-programme, it is expected that new emissions objective for NO x will be suggested for 2015-2020, to cope with health and environment objectives in Europe. The report shows that that development that currently happens within the vehicle industry, for engines and exhaust emission control system are pursued to meet future exhaust requirement in the USA gives good conditions for the road traffic sector to contribute to that these objectives will reached

  3. Differences in fluorescence characteristics and bioavailability of water-soluble organic matter (WSOM) in sediments and suspended solids in Lihu Lake, China.

    Science.gov (United States)

    Wang, Wenwen; Wang, Shuhang; Jiang, Xia; Zheng, Binghui; Zhao, Li; Zhang, Bo; Chen, Junyi

    2018-05-01

    The spectral characteristics, spatial distribution, and bioavailability of water-soluble organic matter (WSOM) in suspended solids and surface sediments of Lihu Lake, China, were investigated through excitation-emission matrix spectra and parallel factor analysis. The average content of dissolved organic carbon (DOC) in the sediments reached 643.28 ± 58.34 mg C/kg and that in suspended solids was 714.87 ± 69.24 mg C/kg. The fluorescence intensity of WSOM totaled 90.87 ± 5.65 and 115.42 ± 8.02 RU/g for the sediments and suspended solids, respectively. The DOC and fluorescence intensity of the WSOM showed an increasing trend moving from the west to the east of the lake. The WSOM in sediments and suspended solids contained two humic-like (C1 and C2) and one tryptophan-like (C3) components. These components had different fluorescent peaks and relative proportions. In the sediments, the relative proportions of C1, C2, and C3 were 33.71% ± 0.71, 26.83% ± 0.68, and 39.50% ± 0.71%, respectively. Meanwhile, C1 (35.77 ± 0.84%), C2 (34.07 ± 0.61%), and C3 (30.16 ± 0.75%) had similar relative percentages in suspended solids. The sediments had a lower humification index (3.02 ± 0.08) than the suspended solids (4.04 ± 0.15). Exchangeable nitrogen for the sediments and suspended solids was dominated by exchangeable ammonium nitrogen and soluble organic nitrogen, respectively. WSOM plays an important role in migration and transformation of nitrogen in sediments and suspended solids. The sediment-derived WSOM exhibited higher lability and biological activity than did the suspended solid-derived WSOM. The relative ratio of the intensity of protein-like fluorescent component to that of the humic-like one can be used as a reference index to evaluate the lability and biological activity of WSOM in sediments and suspended solids.

  4. Effects of nitrogen fertilization and grazing on the emission of nitrous oxide from grassland

    Energy Technology Data Exchange (ETDEWEB)

    Velthof, G.L.; Oenema, O. [Nutrient Management Institute NMI, Wageningen Agricultural University, Wageningen (Netherlands)

    1995-12-31

    Nitrous oxide (N2O) is one of the trace gases that possibly contribute to the depletion of stratospheric ozone and to global warming. Soils are a major source of N2O. Thus far, the contribution of agricultural soils and practises in The Netherlands to the total N2O burden of the atmosphere is largely unknown, because in-situ field measurements are scarce. In the research project reported here, effects of nitrogen (N) fertilization, grazing animals and soil type on N2O emission from grassland in The Netherlands were investigated. The aim of these investigations was to provide insight into the major factors that contribute to N2O emission from managed grassland and to provide quantitative N2O emission rates, obtained from field measurements. The research programme was split in three parts. First, a monitoring study, in which fluxes of N2O were measured weekly at four contrasting grassland sites with three different management practices each, during a period of two years. Secondly, field and greenhouse studies, in which the temporal and spatial variability of N2O fluxes, the effects of type and level of N fertilizer application and the effect of groundwater level on N2O emissions from grassland were assessed in detail. Thirdly, model calculations in which the possibilities were assessed of the use of improved nutrient management as tool to reduce N2O losses from dairy farming systems in The Netherlands, using a whole-farm approach. figs., tabs., refs.

  5. 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.

  6. [Study on optical characteristics of chromophoric dissolved organic matter (CDOM) in rainwater by fluorescence excitation-emission matrix and absorbance spectroscopy].

    Science.gov (United States)

    Cheng, Yuan-yue; Guo, Wei-dong; Long, Ai-min; Chen, Shao-yong

    2010-09-01

    The optical characteristics of chromophoric dissolved organic matter (CDOM) were determined in rain samples collected in Xiamen Island, during a rainy season in 2007, using fluorescence excitation-emission matrix spectroscopy associated with UV-Vis absorbance spectra. Results showed that the absorbance spectra of CDOM in rain samples decreased exponentially with wavelength. The absorbance coefficient at 300 nm [a(300)] ranged from 0.27 to 3.45 m(-1), which would be used as an index of CDOM abundance, and the mean value was 1.08 m(-1). The content of earlier stage of precipitation events was higher than that of later stage of precipitation events, which implied that anthropogenic sources or atmospheric pollution or air mass types were important contributors to CDOM levels in precipitation. EEMs spectra showed 4 types of fluorescence signals (2 humic-like fluorescence peaks and 2 protein-like fluorescence peaks) in rainwater samples, and there were significant positive correlations of peak A with C and peak B with S, showing their same sources or some relationship of the two humic-like substance and the two protein-like substance. The strong positive correlations of the two humic-like fluorescence peaks with a(300), suggested that the chromophores responsible for absorbance might be the same as fluorophores responsible for fluorescence. Results showed that the presence of highly absorbing and fluorescing CDOM in rainwater is of significant importance in atmospheric chemistry and might play a previously unrecognized role in the wavelength dependent spectral attenuation of solar radiation by atmospheric waters.

  7. Atmospheric Nitrogen Trifluoride: Optimized emission estimates using 2-D and 3-D Chemical Transport Models from 1973-2008

    Science.gov (United States)

    Ivy, D. J.; Rigby, M. L.; Prinn, R. G.; Muhle, J.; Weiss, R. F.

    2009-12-01

    We present optimized annual global emissions from 1973-2008 of nitrogen trifluoride (NF3), a powerful greenhouse gas which is not currently regulated by the Kyoto Protocol. In the past few decades, NF3 production has dramatically increased due to its usage in the semiconductor industry. Emissions were estimated through the 'pulse-method' discrete Kalman filter using both a simple, flexible 2-D 12-box model used in the Advanced Global Atmospheric Gases Experiment (AGAGE) network and the Model for Ozone and Related Tracers (MOZART v4.5), a full 3-D atmospheric chemistry model. No official audited reports of industrial NF3 emissions are available, and with limited information on production, a priori emissions were estimated using both a bottom-up and top-down approach with two different spatial patterns based on semiconductor perfluorocarbon (PFC) emissions from the Emission Database for Global Atmospheric Research (EDGAR v3.2) and Semiconductor Industry Association sales information. Both spatial patterns used in the models gave consistent results, showing the robustness of the estimated global emissions. Differences between estimates using the 2-D and 3-D models can be attributed to transport rates and resolution differences. Additionally, new NF3 industry production and market information is presented. Emission estimates from both the 2-D and 3-D models suggest that either the assumed industry release rate of NF3 or industry production information is still underestimated.

  8. Fabrication of fluorescent chitosan-containing microcapsules

    Directory of Open Access Journals (Sweden)

    Zhang R.

    2013-08-01

    Full Text Available Intense emission peaks of Eu(DBM3Phen (DBM and Phen are dibenzoylmethane and 1,10-phenanthroline, respectively in the microcapsules containing molecules of quaternary ammonium chitosan (QACS and sodium alginate are observed. The microcapsules are assembled by using CaCO3 particles as template cores by the layer-by-layer (LbL technique. Observation of microcapsules by the fluorescence mode and the transmission mode in the confocal laser scanning microscopy shows that the microcapsules are intact after core decomposition. Fluorescence under ultraviolet irradiation comes directly from the Eu(DBM3Phen. Homogeneous assembly of Eu(DBM3Phen can be deduced due to the homogeneous fluorescence of the microcapsules in the fluorescence micrographs. The microcapsules show adherence to solid substrates due to large quantities of hydroxyl groups of QACS. AFM measurements of dried hollow microcapsules with only 4 bilayers of (CS/SA fabricated with Eu(DBM3Phen show the intact shell with a thickness of 3.0 nm. Regarding the biocompatible natural polysaccharides and the intense fluorescence emission, the microcapsules in this work might be of great importance in potential application in drug delivery and bioassay.

  9. Contribution of waterborne nitrogen emissions to hypoxia-driven marine eutrophication: modelling of damage to ecosystems in life cycle impact assessment (LCIA)

    DEFF Research Database (Denmark)

    Cosme, Nuno Miguel Dias

    Marine eutrophication refers to the ecosystem response to the loading of a growth limiting nutrient, typically nitrogen (N), to coastal waters, where it may cause several impacts. One of the possible impact pathways to these impacts involves the excessive depletion of dissolved oxygen hypoxia) in...... and atmospheric deposition as a consequence of fossil fuels combustion.......Marine eutrophication refers to the ecosystem response to the loading of a growth limiting nutrient, typically nitrogen (N), to coastal waters, where it may cause several impacts. One of the possible impact pathways to these impacts involves the excessive depletion of dissolved oxygen hypoxia......) in bottom waters. Hypoxia is identified as an important and widespread cause of disturbance to marine ecosystems and has been linked to the increasing anthropogenic pressure. This is driven by environmental emissions of reactive nitrogen, mainly from N-containing fertilizers used in agriculture...

  10. Quantifying the effect of interactions between disease control, nitrogen supply and land use change on the greenhouse gas emissions associated with wheat production

    DEFF Research Database (Denmark)

    Berry, P M; Kindred, D R; Olesen, Jørgen E

    2010-01-01

    A method for calculating the effect of disease control on greenhouse gas (GHG) emissions associated with wheat production, reported previously, was developed further to account for effects of disease control on the amount of fertilizer nitrogen (N) which should be applied and on changes in land use...... that the optimum N rate was used, an additional 481kha of wheat would be required to maintain UK wheat production at the current level. If the additional land area came from converting temperate grassland to arable production, the GHG emissions caused by ploughing grassland would cause emissions to rise from 503...

  11. Detection of intaoral lesions using a fluorescence camera

    Science.gov (United States)

    Thoms, Michael

    2006-02-01

    Optical methods for the detection of carious lesions, calculus and plaque have the advantage of being minimally invasive. The use of endogeneous fluorescence markers like porphyrins could simplify the application of fluorescence techniques in the dental practice. It is known that porphyrins are produced by some of the bacterial species that are present in the oral cavity. Since porphyrins have an excitation band at about 400nm they have the potential to be used as fluorescent markers of locations in the oral cavity where the production of bacteria is out of the limits of healthy regions. Further, modern and efficient GaN-based semiconductor diodes emit light in this spectral range and thus make the implementation of fluorescence sensors with excitation at this wavelength easy. Carious lesions, calculus and plaque have been measured using a self build fluorescence camera using GaN-diodes for illumination at 405nm. Further, emission spectra under this excitation were recorded. For the latter purpose freshly extracted teeth were used. It has been found that already in the case of an initial carious lesion red porphyrin-fluorescence is emitted whereas it is absent in healthy enamel. In already brown coloured carious lesions the emission bands of porphyrin are present but the observed overall fluorescence intensity is lower, probably due to the absorption of the fluorescence by the carious defect itself. In dental calculus, dental plaque and subgingival concrements porphyrin originated luminescence was found as well. Since in these cases the emission spectra differ slightly it can be concluded that they originate from different types of porphyrins and thus also from different bacteria. These results show that this fluorescence technique can be a promising method to diagnose carious lesions, calculus and plaque.

  12. Responses of Surface Ozone Air Quality to Anthropogenic Nitrogen Deposition

    Science.gov (United States)

    Zhang, L.; Zhao, Y.; Tai, A. P. K.; Chen, Y.; Pan, Y.

    2017-12-01

    Human activities have substantially increased atmospheric deposition of reactive nitrogen to the Earth's surface, inducing unintentional effects on ecosystems with complex environmental and climate consequences. One consequence remaining unexplored is how surface air quality might respond to the enhanced nitrogen deposition through surface-atmosphere exchange. We combine a chemical transport model (GEOS-Chem) and a global land model (Community Land Model) to address this issue with a focus on ozone pollution in the Northern Hemisphere. We consider three processes that are important for surface ozone and can be perturbed by addition of atmospheric deposited nitrogen: emissions of biogenic volatile organic compounds (VOCs), ozone dry deposition, and soil nitrogen oxide (NOx) emissions. We find that present-day anthropogenic nitrogen deposition (65 Tg N a-1 to the land), through enhancing plant growth (represented as increases in vegetation leaf area index (LAI) in the model), could increase surface ozone from increased biogenic VOC emissions, but could also decrease ozone due to higher ozone dry deposition velocities. Meanwhile, deposited anthropogenic nitrogen to soil enhances soil NOx emissions. The overall effect on summer mean surface ozone concentrations show general increases over the globe (up to 1.5-2.3 ppbv over the western US and South Asia), except for some regions with high anthropogenic NOx emissions (0.5-1.0 ppbv decreases over the eastern US, Western Europe, and North China). We compare the surface ozone changes with those driven by the past 20-year climate and historical land use changes. We find that the impacts from anthropogenic nitrogen deposition can be comparable to the climate and land use driven surface ozone changes at regional scales, and partly offset the surface ozone reductions due to land use changes reported in previous studies. Our study emphasizes the complexity of biosphere-atmosphere interactions, which can have important

  13. Gas exchange and chlorophyll a fluorescence parameters of ornamental bromeliads

    Directory of Open Access Journals (Sweden)

    Karina Gonçalves da Silva

    2017-10-01

    Full Text Available Gas exchange and chlorophyll a fluorescence are widely used in physiological and ecological studies; however, few studies have used these techniques with ornamental plants. This study tested the potential contribution of gas exchange and chlorophyll a fluorescence to evaluate the water and nutrients uptake by the tank and root system of epiphyte bromeliad Guzmania lingulata. For this purpose, we conducted an experiment with different water regime and another with different concentrations of nitrogen. The experiments were: 1 - Watering: Control (application of water into Tank and Root, Tank (watering into Tank, Root (watering Root and Drought (water suspension during the 90 days of experimentation and 2 - Nitrogen: Plants fertilized with Hoagland and Arnon nutrient solution exclusively into Tank or Root with nitrogen concentrations of control and 2.62 or 5.34 mM N applied as urea. The Fv /Fm ratio allowed comparing the treatments between experiments, demonstrating that Root and Tank both have the capacity to maintain G. lingulata photosynthetic activity and growth, while Drought treatment (water suspension was the limiting factor for energy conversion efficiency of PSII. However, gas exchange was more permissive as a parameter for comparing treatments in the nitrogen experiment, providing important information about the general aspects of the photosynthetic process in the watering experiment. Both gas exchange and chlorophyll a fluorescence can support the evaluation of G. lingulata physiological status and can be useful tools in ornamental horticultural studies.

  14. Ultratrace analysis of transuranic actinides by laser-induced fluorescence

    Science.gov (United States)

    Miller, S.M.

    1983-10-31

    Ultratrace quantities of transuranic actinides are detected indirectly by their effect on the fluorescent emissions of a preselected fluorescent species. Transuranic actinides in a sample are coprecipitated with a host lattice material containing at least one preselected fluorescent species. The actinide either quenches or enhances the laser-induced fluorescence of the preselected fluorescent species. The degree of enhancement or quenching is quantitatively related to the concentration of actinide in the sample.

  15. Secondary electron emission and glow discharge properties of 12CaO·7Al2O3 electride for fluorescent lamp applications

    International Nuclear Information System (INIS)

    Watanabe, Satoru; Watanabe, Toshinari; Ito, Kazuhiro; Miyakawa, Naomichi; Ito, Setsuro; Hosono, Hideo; Mikoshiba, Shigeo

    2011-01-01

    12CaO·7Al 2 O 3 electride, a sub-nanoporous compound having a work function of 2.4 eV, was examined as a candidate cathode material in fluorescent lamps. The electron emission yield was higher and the discharge voltage was lower for 12CaO·7Al 2 O 3 than for existing cathode materials such as Ni, Mo or W; therefore, the energy consumption of the fluorescent lamps can be improved using 12CaO·7Al 2 O 3 cathodes. Prototype glow-discharge lamps using 12CaO·7Al 2 O 3 were constructed and exhibited reasonable durability.

  16. Secondary electron emission and glow discharge properties of 12CaO·7Al2O3 electride for fluorescent lamp applications.

    Science.gov (United States)

    Watanabe, Satoru; Watanabe, Toshinari; Ito, Kazuhiro; Miyakawa, Naomichi; Ito, Setsuro; Hosono, Hideo; Mikoshiba, Shigeo

    2011-06-01

    12CaO·7Al 2 O 3 electride, a sub-nanoporous compound having a work function of 2.4 eV, was examined as a candidate cathode material in fluorescent lamps. The electron emission yield was higher and the discharge voltage was lower for 12CaO·7Al 2 O 3 than for existing cathode materials such as Ni, Mo or W; therefore, the energy consumption of the fluorescent lamps can be improved using 12CaO·7Al 2 O 3 cathodes. Prototype glow-discharge lamps using 12CaO·7Al 2 O 3 were constructed and exhibited reasonable durability.

  17. Secondary electron emission and glow discharge properties of 12CaOcenterdot7Al2O3 electride for fluorescent lamp applications

    Directory of Open Access Journals (Sweden)

    Satoru Watanabe, Toshinari Watanabe, Kazuhiro Ito, Naomichi Miyakawa, Setsuro Ito, Hideo Hosono and Shigeo Mikoshiba

    2011-01-01

    Full Text Available 12CaOcenterdot7Al2O3 electride, a sub-nanoporous compound having a work function of 2.4 eV, was examined as a candidate cathode material in fluorescent lamps. The electron emission yield was higher and the discharge voltage was lower for 12CaOcenterdot7Al2O3 than for existing cathode materials such as Ni, Mo or W; therefore, the energy consumption of the fluorescent lamps can be improved using 12CaOcenterdot7Al2O3 cathodes. Prototype glow-discharge lamps using 12CaOcenterdot7Al2O3 were constructed and exhibited reasonable durability.

  18. Compact three-dimensional super-resolution system based on fluorescence emission difference microscopy

    Science.gov (United States)

    Zhu, Dazhao; Chen, Youhua; Fang, Yue; Hussain, Anwar; Kuang, Cuifang; Zhou, Xiaoxu; Xu, Yingke; Liu, Xu

    2017-12-01

    A compact microscope system for three-dimensional (3-D) super-resolution imaging is presented. The super-resolution capability of the system is based on a size-reduced effective 3-D point spread function generated through the fluorescence emission difference (FED) method. The appropriate polarization direction distribution and manipulation allows the panel active area of the spatial light modulator to be fully utilized. This allows simultaneous modulation of the incident light by two kinds of phase masks to be performed with a single spatial light modulator in order to generate a 3-D negative spot. The system is more compact than standard 3-D FED systems while maintaining all the advantages of 3-D FED microscopy. The experimental results demonstrated the improvement in 3-D resolution by nearly 1.7 times and 1.6 times compared to the classic confocal resolution in the lateral and axial directions, respectively.

  19. 76 FR 52283 - Approval and Promulgation of Air Quality Implementation Plans; Pennsylvania; Control of Nitrogen...

    Science.gov (United States)

    2011-08-22

    ... Promulgation of Air Quality Implementation Plans; Pennsylvania; Control of Nitrogen Oxides Emissions From Glass... revisions pertain to the control of nitrogen oxide (NO X ) emissions from glass melting furnaces. EPA is..., Nitrogen dioxide, Ozone, Particulate matter, Reporting and recordkeeping requirements. Dated: August 8...

  20. 76 FR 34021 - Approval and Promulgation of Air Quality Implementation Plans; Pennsylvania; Control of Nitrogen...

    Science.gov (United States)

    2011-06-10

    ... Promulgation of Air Quality Implementation Plans; Pennsylvania; Control of Nitrogen Oxides Emissions From Glass... Pennsylvania. This revision pertains to the control of nitrogen oxide (NO X ) emissions from glass melting... protection, Air pollution control, Nitrogen dioxide, Ozone, Particulate matter, Reporting and recordkeeping...

  1. Color-tunable and stable-efficiency white organic light-emitting diode fabricated with fluorescent-phosphorescent emission layers

    International Nuclear Information System (INIS)

    Yang, Su-Hua; Shih, Po-Jen; Wu, Wen-Jie; Huang, Yi-Hua

    2013-01-01

    White organic light emitting diodes (OLEDs) were fabricated for color-tunable lighting applications. Fluorescent and phosphorescent hybrid emission layers (EMLs) were used to enhance the luminance and stability of the devices, which have blue-EML/CBP interlayer/green-EML/phosphorescent-sensitized-EML/red-EML structures. The influence of the composition and structure of the EMLs on the electroluminescence properties of the devices were investigated from the viewpoint of their emission spectra. The possible exciton harvesting, diffusion, transport, and annihilation processes occurring in the EMLs were also evaluated. A maximum luminance intensity of 7400 cd/m 2 and a highly stable current efficiency of 3.2 cd/A were obtained. Good color tunability was achieved for the white OLEDs; the chromatic coordinates linearly shifted from pure white (0.300, 0.398) to cold white (0.261, 0.367) when the applied voltage was varied from 10 to 14 V. -- Highlights: • Exciton harvesting, diffusion, transport, and annihilation processes were evaluated. • The electroluminescence properties were investigated from the viewpoint of the emission spectra. • Good color tunability and stable-efficiency were achieved for the white OLEDs

  2. Realizing Highly Efficient Solution-Processed Homojunction-Like Sky-Blue OLEDs by Using Thermally Activated Delayed Fluorescent Emitters Featuring an Aggregation-Induced Emission Property.

    Science.gov (United States)

    Wu, Kailong; Wang, Zian; Zhan, Lisi; Zhong, Cheng; Gong, Shaolong; Xie, Guohua; Yang, Chuluo

    2018-04-05

    Two new blue emitters, i.e., bis-[2-(9,9-dimethyl-9,10-dihydroacridine)-phenyl]-sulfone ( o-ACSO2) and bis-[3-(9,9-dimethyl-9,10-dihydroacridine)-phenyl]-sulfone ( m-ACSO2), with reserved fine thermally activated delayed fluorescent (TADF) nature and simply tuned thermal and optoelectronic properties, were synthesized by isomer engineering. The meta-linking compound, i.e., m-ACSO2, obtains the highest photoluminescence quantum yield with a small singlet-triplet energy gap, a moderate delayed fluorescent lifetime, excellent solubility, and neat film homogeneity. Due to its unique aggregation-induced emission (AIE) character, neat film-based heterojunction-like organic light-emitting diodes (OLEDs) are achievable. By inserting an excitonic inert exciton-blocking layer, the PN heterojunction-like emission accompanied by intefacial exciplex was shifted to a homojunction-like channel mainly from the AIE emitter itself, providing a new tactic to generate efficient blue color from neat films. The solution-processed nondoped sky-blue OLED employing m-ACSO2 as emitter with homojunction-like emission achieved a maximum external quantum efficiency of 17.2%. The design strategies presented herein provide practical methods to construct efficient blue TADF dyes and realize high-performance blue TADF devices.

  3. Evaluation of consequences of emissions to air from the Sture oil terminal

    International Nuclear Information System (INIS)

    Knudsen, S.; Sloerdal, L.H.

    1997-01-01

    This report evaluates the consequences of emissions of NOx and volatile organic compounds (VOCs) from a planned gas recovery plant at Sture in the Norwegian municipality of Oeygarden. The new plant will distill methane and naphtha from crude oil and the emissions of VOC from loading the oil will be partly recovered. The report discusses the effects of emissions to air locally around the plant, regional deposition of nitrogen compounds and formation of ozone caused by the emissions of VOC and NOx. Calculations show that depositions of nitrogen compounds from emissions of nitrogen oxides from Sture contribute little to the nitrogen deposition in the area. The contribution of acids from nitrogen oxide emission will be too low to have measurable consequences for the acidification of the lakes in the region concerned. At times the present background level of ozone at Sture is high enough to cause reduced photosynthesis and plant growth. The ozone concentration will be little influenced by VOC emissions. The increased ozone concentration at ground level following emissions of nitrogen oxides and hydrocarbons is too low to affect the vegetation in the area. 9 refs., 5 figs., 4 tabs

  4. Effect of increased fuel temperature on emissions of oxides of nitrogen from a gas turbine combustor burning ASTM jet-A fuel

    Science.gov (United States)

    Marchionna, N. R.

    1974-01-01

    An annular gas turbine combustor was tested with heated ASTM Jet-A fuel to determine the effect of increased fuel temperature on the formation of oxides of nitrogen. Fuel temperature ranged from ambient to 700 K. The NOx emission index increased at a rate of 6 percent per 100 K increase in fuel temperature.

  5. Nitrogen Saturation in Temperate Forest Ecosystems

    Science.gov (United States)

    John Aber; William McDowell; Knute Nadelhoffer; Alison Magill; Glenn Berntson; Mark Kamakea; Steven McNulty; William Currie; Lindsey Rustad; Ivan Fernandez

    1998-01-01

    Nitrogen emissions to the atmosphere due to human activity remain elevated in industrialized regions of the world and are accelerating in many developing regions (Galloway 1995). Although the deposition of sulfur has been reduced over much of the United States and Europe by aggressive environmental protection policies, current nitrogen deposition reduction targets in...

  6. Economics of low nitrogen feeding strategies

    NARCIS (Netherlands)

    Vuuren, van A.M.; Pineiro, C.; Hoek, Van der K.W.; Oenema, O.

    2015-01-01

    Livestock retains typically between 10 and 40 % of the protein-nitrogen in the animal feed in milk, egg and/or meat, depending also on animal productivity and management. The remaining 60–90 % of the nitrogen (N) is excreted in urine and faeces, and contributes to the emissions of ammonia (NH3) and

  7. Dual Functional Core-Shell Fluorescent Ag2S@Carbon Nanostructure for Selective Assay of E. coli O157:H7 and Bactericidal Treatment.

    Science.gov (United States)

    Wang, Ning; Wei, Xing; Zheng, An-Qi; Yang, Ting; Chen, Ming-Li; Wang, Jian-Hua

    2017-03-24

    A dual functional fluorescent core-shell Ag 2 S@Carbon nanostructure is prepared by a hydrothermally assisted multi-amino synthesis approach with folic acid (FA), polyethylenimine (PEI), and mannoses (Mans) as carbon and nitrogen sources (FA-PEI-Mans-Ag 2 S nanocomposite shortly as Ag 2 S@C). The nanostructure exhibits strong fluorescent emission at λ ex /λ em = 340/450 nm with a quantum yield of 12.57 ± 0.52%. Ag 2 S@C is bound to E. coli O157:H7 via strong interaction with the Mans moiety in Ag 2 S@C with FimH proteins on the fimbriae tip in E. coli O157:H7. Fluorescence emission from Ag 2 S@C/E. coli conjugate is closely related to the content of E. coli O157:H7. Thus, a novel procedure for fluorescence assay of E. coli O157:H7 is developed, offering a detection limit of 330 cfu mL -1 . Meanwhile, the Ag 2 S@C nanostructure exhibits excellent antibacterial performance against E. coli O157:H7. A 99.9% sterilization rate can be readily achieved for E. coli O157:H7 at a concentration of 10 6 -10 7 cfu mL -1 with 3.3 or 10 μg mL -1 of Ag 2 S@C with an interaction time of 5 or 0.5 min, respectively.

  8. Proposition of primary methods for nitrogen oxides emissions reduction at coal-fired 200 MW power unit (Yugoslavia)

    International Nuclear Information System (INIS)

    Repic, B.; Mladenovic, R.; Crnomarkovic, N.

    1997-01-01

    The combustion of coal is followed by increased pollution of the environment with toxic products. Together with the generation of other pollutants, the emission of nitrogen oxides (NO x ) represents, due to its high toxicity, a great environmental risk. Appropriate measures must be taken for lowering NO x emission, both on new facilities and those already in operation. Basic technologies (primary reduction methods) of several generations, developed until now and used in practice, are presented in the paper. The technologies applicable on domestic facilities and adjusted to domestic coals have been given particular consideration. Proposition of primary methods for NO x emission reduction at coal-fired 200 MW power unit at TPS 'Nikola Tesla' is analyzed. The following methods have been considered in detail: flue gases recirculation, multi-stage combustion, low-NO x burners, additional over-fire air, multi-stage air intake into the furnace, staged fuel injection, grinding fineness increase, etc. Considerations were performed according to existing constructive characteristics of the furnace and the burners, and characteristics of used fuels, i. e. lignites from Kolubara pit. (Author)

  9. SUZAKU OBSERVATION OF STRONG FLUORESCENT IRON LINE EMISSION FROM THE YOUNG STELLAR OBJECT V1647 ORI DURING ITS NEW X-RAY OUTBURST

    International Nuclear Information System (INIS)

    Hamaguchi, Kenji; Grosso, Nicolas; Kastner, Joel H.; Richmond, Michael; Weintraub, David A.

    2010-01-01

    The Suzaku X-ray satellite observed the young stellar object (YSO) V1647 Ori on 2008 October 8 during the new mass accretion outburst reported in 2008 August. During the 87 ks observation with a net exposure of 40 ks, V1647 Ori showed a high level of X-ray emission with a gradual decrease in flux by a factor of 5 and then displayed an abrupt flux increase by an order of magnitude. Such enhanced X-ray variability was also seen in XMM-Newton observations in 2004 and 2005 during the 2003-2005 outburst, but has rarely been observed for other YSOs. The spectrum clearly displays emission from Helium-like iron, which is a signature of hot plasma (kT ∼ 5 keV). It also shows a fluorescent iron Kα line with a remarkably large equivalent width (EW) of ∼600 eV. Such a large EW suggests that a part of the incident X-ray emission that irradiates the circumstellar material and/or the stellar surface is hidden from our line of sight. XMM-Newton spectra during the 2003-2005 outburst did not show a strong fluorescent iron Kα line, so that the structure of the circumstellar gas very close to the stellar core that absorbs and re-emits X-ray emission from the central object may have changed in between 2005 and 2008. This phenomenon may be related to changes in the infrared morphology of McNeil's nebula between 2004 and 2008.

  10. NOS module - reducing the nitrogen oxides and dust emissions of wood-fired systems; NOS-Modul. Installation und Test - Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Salerno, B.

    2005-07-01

    This final report for the Swiss Federal Office of Energy (SFOE) presents the results of a project that examined the potential of reducing dust and nitrogen oxides emissions of biomass-fired systems. Two prototype installations are described with capacities of 70 - 300 kW and 150 - 500 kW, the latter being a mobile installation installed together with a silo in a container. The prototypes can burn problematical biomass such as cereals, chicken droppings, damp wood-chippings and straw. Various factors and configurations influencing the formation of emissions are examined. Cyclone technology, a catalyst using chrome-nickel shavings and a ceramic heat-exchanger are discussed. Measurements made are presented in tabular and graphical form and discussed.

  11. Metal plasmon-coupled fluorescence imaging and label free coenzyme detection in cells

    International Nuclear Information System (INIS)

    Zhang, Jian; Fu, Yi; Li, Ge; Zhao, Richard Y.

    2012-01-01

    Highlights: ► Metal nanoparticle for fluorescence cell imaging. ► Non-invasive emission detection of coenzyme in cell on time-resolved confocal microscope. ► Near-field interaction of flavin adenine dinucleotide with silver substrate. ► Isolation of emissions by coenzymes from cellular autofluorescence on fluorescence cell imaging. -- Abstract: Flavin adenine dinucleotide (FAD) is a key metabolite in cellular energy conversion. Flavin can also bind with some enzymes in the metabolic pathway and the binding sites may be changed due to the disease progression. Thus, there is interest on studying its expression level, distribution, and redox state within the cells. FAD is naturally fluorescent, but it has a modest extinction coefficient and quantum yield. Hence the intrinsic emission from FAD is generally too weak to be isolated distinctly from the cellular backgrounds in fluorescence cell imaging. In this article, the metal nanostructures on the glass coverslips were used as substrates to measure FAD in cells. Particulate silver films were fabricated with an optical resonance near the absorption and the emission wavelengths of FAD which can lead to efficient coupling interactions. As a result, the emission intensity and quantum yield by FAD were greatly increased and the lifetime was dramatically shortened resulting in less interference from the longer lived cellular background. This feature may overcome the technical limits that hinder the direct observation of intrinsically fluorescent coenzymes in the cells by fluorescence microscopy. Fluorescence cell imaging on the metallic particle substrates may provide a non-invasive strategy for collecting the information of coenzymes in cells.

  12. Influence of fertilizer nitrogen source and management practice of N2O emissions from two black chernozemic soils

    International Nuclear Information System (INIS)

    Burton, D.L.

    2008-01-01

    Nitrous oxide (N 2 O) is a major anthropogenic greenhouse gas (GHG) emitted by Canadian agricultural systems. Emissions of N 2 O are sporadic, which complicates their accurate quantification as well as the development of adequate management practices. This study was conducted to determine the relative N 2 O production potentials of various nitrogen (N) fertilizer sources and application methods used in cereal production practices in Manitoba. Wheat crops were used to examine variations in N 2 O emissions associated with N formulations applied at the same rate. Treatments included urea surface broadcast in the spring; urea subsurface bands in spring; urea subsurface bands in the fall; anhydrous ammonia subsurface bands in spring and fall; and a control plot where no N was applied. Treatments of polymer-coated urea were also applied. The treatments were established in the fall of 1999. N 2 O fluxes were measured using vented static chambers. Samples were analyzed using gas chromatography. Analysis of variance (ANOVA) was performed in order to obtain cumulative annual N 2 O emissions. Results of the study showed that N 2 O emissions associated with the use of anhydrous ammonia were no greater than emissions associated with urea. Higher N 2 O emissions were observed in fall applications of N fertilizer. The dominant factors controlling differences in N 2 O emissions between sites and years included precipitation, soil water content, and soil texture. 26 refs., 6 tabs

  13. Preparation and Characterization of Highly Fluorescent, Glutathione-coated Near Infrared Quantum Dots for in Vivo Fluorescence Imaging

    Directory of Open Access Journals (Sweden)

    Yoshichika Yoshioka

    2008-10-01

    Full Text Available Fluorescent probes that emit in the near-infrared (NIR, 700-1,300 nm region are suitable as optical contrast agents for in vivo fluorescence imaging because of low scattering and absorption of the NIR light in tissues. Recently, NIR quantum dots (QDs have become a new class of fluorescent materials that can be used for in vivo imaging. Compared with traditional organic fluorescent dyes, QDs have several unique advantages such as size- and composition-tunable emission, high brightness, narrow emission bands, large Stokes shifts, and high resistance to photobleaching. In this paper, we report a facile method for the preparation of highly fluorescent, water-soluble glutathione (GSH-coated NIR QDs for in vivo imaging. GSH-coated NIR QDs (GSH-QDs were prepared by surface modification of hydrophobic CdSeTe/CdS (core/shell QDs. The hydrophobic surface of the CdSeTe/CdS QDs was exchanged with GSH in tetrahydrofuran-water. The resulting GSH-QDs were monodisperse particles and stable in PBS (phosphate buffered saline, pH = 7.4. The GSH-QDs (800 nm emission were highly fluorescent in aqueous solutions (quantum yield = 22% in PBS buffer, and their hydrodynamic diameter was less than 10 nm, which is comparable to the size of proteins. The cellular uptake and viability for the GSH-QDs were examined using HeLa and HEK 293 cells. When the cells were incubated with aqueous solutions of the GSH-QDs (10 nM, the QDs were taken into the cells and distributed in the perinuclear region of both cells. After 12 hrs incubation of 4 nM of GSH-QDs, the viabilities of HeLa and HEK 293 cells were ca. 80 and 50%, respectively. As a biomedical utility of the GSH-QDs, in vivo NIRfluorescence imaging of a lymph node in a mouse is presented.

  14. [Fluorescence spectra analysis of the scrophularia soup].

    Science.gov (United States)

    Yan, Li-hua; Song, Feng; Han, Juan; Su, Jing; Qu, Fei-fei; Song, Yi-zhan; Hu, Bo-lin; Tian, Jian-guo

    2008-08-01

    The cold-water and boiled-water soaked scrophularia soups have been prepared. The emission and excitation spectra of each scrophularia soup under different conditions have been measured at room temperature. The pH values of the different scrophularia soups have been also detected. There are obvious differences between the cold-water soaked scrophularia soup and the boiled-water soaked scrophularia. For both soups the emission wavelength increases with the wavelength of the excitation, but the peaks of the emission spectra for cold-water and boiled-water soaked scrophularia soup are different, which are 441 and 532 nm, respectively. Excitation spectrum has double peaks in the cold-water soaked scrophularia soup while only one peak with longer wavelength in the boiled-water soaked one. The pH value changes from 5.5 to 4.1. According to the organic admixture fluorescence mechanism we analyzed the reasons of the experimental results. Through heating, the interaction in different fluorescence molecular and the energy transfer process in the same fluorescence molecular become more active, and the conjugate structures and the generation of hydrogen bonds, increase. The fluorescence measurement is of value for the scrophularia pharmacology analysis and provides an analytical method for the quality identification of scrophularia soup.

  15. Fluorescent Probes and Fluorescence (Microscopy Techniques — Illuminating Biological and Biomedical Research

    Directory of Open Access Journals (Sweden)

    Gregor P. C. Drummen

    2012-11-01

    Full Text Available Fluorescence, the absorption and re-emission of photons with longer wavelengths, is one of those amazing phenomena of Nature. Its discovery and utilization had, and still has, a major impact on biological and biomedical research, since it enables researchers not just to visualize normal physiological processes with high temporal and spatial resolution, to detect multiple signals concomitantly, to track single molecules in vivo, to replace radioactive assays when possible, but also to shed light on many pathobiological processes underpinning disease states, which would otherwise not be possible. Compounds that exhibit fluorescence are commonly called fluorochromes or fluorophores and one of these fluorescent molecules in particular has significantly enabled life science research to gain new insights in virtually all its sub-disciplines: Green Fluorescent Protein. Because fluorescent proteins are synthesized in vivo, integration of fluorescent detection methods into the biological system via genetic techniques now became feasible. Currently fluorescent proteins are available that virtually span the whole electromagnetic spectrum. Concomitantly, fluorescence imaging techniques were developed, and often progress in one field fueled innovation in the other. Impressively, the properties of fluorescence were utilized to develop new assays and imaging modalities, ranging from energy transfer to image molecular interactions to imaging beyond the diffraction limit with super-resolution microscopy. Here, an overview is provided of recent developments in both fluorescence imaging and fluorochrome engineering, which together constitute the “fluorescence toolbox” in life science research.

  16. The camera of the Pierre Auger Observatory Fluorescence Detector

    CERN Document Server

    Ambrosio, M; Bracci, F; Facal, P; Fonte, R; Gallo, G; Kemp, E; Matthiae, Giorgio; Nicotra, D; Privitera, P; Raia, G; Tusi, E; Vitali, G

    2002-01-01

    The Fluorescence Detector of the Pierre Auger Observatory is a set of telescopes which measure the fluorescence light emitted by atmospheric nitrogen stimulated by the cosmic-ray showers. The Camera is an array of photomultipliers positioned on the telescope focal surface. We describe the main features of the camera: the hexagonal pixels geometry on the spherical focal surface; the light collectors which complement the photomultipliers; the photomultipliers test.

  17. The camera of the Pierre Auger Observatory Fluorescence Detector

    Energy Technology Data Exchange (ETDEWEB)

    Ambrosio, M.; Aramo, C.; Bracci, F.; Facal, P.; Fonte, R.; Gallo, G.; Kemp, E. E-mail: kemp@roma2.infn.it; Matthiae, G.; Nicotra, D.; Privitera, P.; Raia, G.; Tusi, E.; Vitali, G

    2002-02-01

    The Fluorescence Detector of the Pierre Auger Observatory is a set of telescopes which measure the fluorescence light emitted by atmospheric nitrogen stimulated by the cosmic-ray showers. The Camera is an array of photomultipliers positioned on the telescope focal surface. We describe the main features of the camera: the hexagonal pixels geometry on the spherical focal surface; the light collectors which complement the photomultipliers; the photomultipliers test.

  18. The camera of the Pierre Auger Observatory Fluorescence Detector

    International Nuclear Information System (INIS)

    Ambrosio, M.; Aramo, C.; Bracci, F.; Facal, P.; Fonte, R.; Gallo, G.; Kemp, E.; Matthiae, G.; Nicotra, D.; Privitera, P.; Raia, G.; Tusi, E.; Vitali, G.

    2002-01-01

    The Fluorescence Detector of the Pierre Auger Observatory is a set of telescopes which measure the fluorescence light emitted by atmospheric nitrogen stimulated by the cosmic-ray showers. The Camera is an array of photomultipliers positioned on the telescope focal surface. We describe the main features of the camera: the hexagonal pixels geometry on the spherical focal surface; the light collectors which complement the photomultipliers; the photomultipliers test

  19. A critical analysis of nitrous oxide emissions from animal manure

    International Nuclear Information System (INIS)

    Klemendtsson, Aa.K.; Klemedtsson, L.

    2002-01-01

    Emission of nitrous oxide, N 2 0, alter manure applications to agricultural soil is composed of two components. The first is the immediately increased potential for N 2 0 production due to favourable conditions in the manure-soil environment. More N 2 0 is produced and emitted when the nitrogen content of the manure is high, especially the mineral nitrogen content. The amount of carbon available for microbiological decomposition and water content regulate the oxygen availability, which is important for N 2 0 production in both nitrification and denitrification. The balance between mineralisation of organically bound nitrogen and immobilisation of mineral nitrogen by microorganisms and plants control the availability of N for N 2 0 production. The initial burst of N 2 0 to the atmosphere following manure application may last for two months, while a second component is long term and due to nitrogen in organic matter accumulating in the soil, resulting in a small increase in background emissions over many years due to nitrogen cycling. The IPCC emission factor for N 2 0 emission due to manure addition accounts for the increased emission of N 2 0 during the first year, whereas the long-term emission is not included. (au)

  20. Fluorescence spectral properties of outer antenna LHC II

    CERN Document Server

    He Jun Fang; Zhang, Shu; He Fang Tao; Ren Zhao You; Li Liang Bi; Kuang Ting Yun

    2002-01-01

    Outer antenna LHC II acts to absorb and transfer energy for photosynthesis. The authors studied the fluorescence properties of LHC II of spinach with scanning imaging fluorescence spectroscopy. After it had been excited by 514.5 nm laser, the integral fluorescence spectrum of LHC II was detected. It was shown that energy transfer existed between carotenoid and chlorophyll. Seven bands of LHC II fluorescence emission were resolved by Gauss combination, viz. 656.7, 664.6, 671.5, 677.2, 683.5, 689.6, 695.3 nm, and the percentages of them were 3.0%, 13.1%,13.3%, 21.1%, 13.2%, 33.3%, 3.0% respectively. The emission of 658.7 nm was attributed to chlorophyll b, the other emission bands were produced by chlorophyll a molecules with the maximum absorption 662, 670/671, 676, 680 nm and over 690 nm. The band 656.7 nm, whose percentage was 3.0%, shows that the most energy was absorbed by chlorophyll a. The percentage of band 689.6 nm was the most, which was possibly correlated with one type of self protective mechanism o...

  1. Atmospheric Nitrogen Deposition in the Western United States: Sources, Sinks and Changes over Time

    Science.gov (United States)

    Anderson, Sarah Marie

    Anthropogenic activities have greatly modified the way nitrogen moves through the atmosphere and terrestrial and aquatic environments. Excess reactive nitrogen generated through fossil fuel combustion, industrial fixation, and intensification of agriculture is not confined to anthropogenic systems but leaks into natural ecosystems with consequences including acidification, eutrophication, and biodiversity loss. A better understanding of where excess nitrogen originates and how that changes over time is crucial to identifying when, where, and to what degree environmental impacts occur. A major route into ecosystems for excess nitrogen is through atmospheric deposition. Excess nitrogen is emitted to the atmosphere where it can be transported great distances before being deposited back to the Earth's surface. Analyzing the composition of atmospheric nitrogen deposition and biological indicators that reflect deposition can provide insight into the emission sources as well as processes and atmospheric chemistry that occur during transport and what drives variation in these sources and processes. Chapter 1 provides a review and proof of concept of lichens to act as biological indicators and how their elemental and stable isotope composition can elucidate variation in amounts and emission sources of nitrogen over space and time. Information on amounts and emission sources of nitrogen deposition helps inform natural resources and land management decisions by helping to identify potentially impacted areas and causes of those impacts. Chapter 2 demonstrates that herbaria lichen specimens and field lichen samples reflect historical changes in atmospheric nitrogen deposition from urban and agricultural sources across the western United States. Nitrogen deposition increases throughout most of the 20 th century because of multiple types of emission sources until the implementation of the Clean Air Act Amendments of 1990 eventually decrease nitrogen deposition around the turn of

  2. Detection of Counterfeit Tequila by Fluorescence Spectroscopy

    Directory of Open Access Journals (Sweden)

    José Manuel de la Rosa Vázquez

    2015-01-01

    Full Text Available An ultraviolet (UV light induced fluorescence study to discriminate fake tequila from genuine ones is presented. A portable homemade system based on four light emitting diodes (LEDs from 255 to 405 nm and a miniature spectrometer was used. It has been shown that unlike fake and silver tequila, which produce weak fluorescence signal, genuine mixed, rested, and aged tequilas show high fluorescence emission in the range from 400 to 750 nm. The fluorescence intensity grows with aging in 100% agave tequila. Such fluorescence differences can even be observed with naked eyes. The presented results demonstrate that the fluorescence measurement could be a good method to detect counterfeit tequila.

  3. Detection from space of a reduction in anthropogenic emissions of nitrogen oxides during the Chinese economic downturn

    Science.gov (United States)

    Lin, J.-T.; McElroy, M. B.

    2011-08-01

    Rapid economic and industrial development in China and relatively weak emission controls have resulted in significant increases in emissions of nitrogen oxides (NOx) in recent years, with the exception of late 2008 to mid 2009 when the economic downturn led to emission reductions detectable from space. Here vertical column densities (VCDs) of tropospheric NO2 retrieved from satellite observations by SCIAMACHY, GOME-2 and OMI (both by KNMI and by NASA) are used to evaluate changes in emissions of NOx from October 2004 to February 2010 identifying impacts of the economic downturn. Data over polluted regions of Northern East China suggest an increase of 27-33 % in 12-month mean VCD of NO2 prior to the downturn, consistent with an increase of 49 % in thermal power generation (TPG) reflecting the economic growth. More detailed analysis is used to quantify changes in emissions of NOx in January over the period 2005-2010 when the effect of the downturn was most evident. The GEOS-Chem model is employed to evaluate the effect of changes in chemistry and meteorology on VCD of NO2. This analysis indicates that emissions decreased by 20 % from January 2008 to January 2009, close to the reduction of 18 % in TPG that occurred over the same interval. A combination of three independent approaches indicates that the economic downturn was responsible for a reduction in emissions by 9-11 % in January 2009 with an additional decrease of 10 % attributed to the slow-down in industrial activity associated with the coincident celebration of the Chinese New Year; errors in the estimate are most likely less than 3.4 %.

  4. Characterisation of estuarine intertidal macroalgae by laser-induced fluorescence

    DEFF Research Database (Denmark)

    Gameiro, Carla; Utkin, Andrei B.; Sousa Dias Cartaxana, Paulo Jorge

    2015-01-01

    The article reports the application of laser-induced fluorescence (LIF) for the assessment of macroalgae communities of estuarine intertidal areas. The method was applied for the characterisation of fifteen intertidal macroalgae species of the Tagus estuary, Portugal, and adjacent coastal area...... spectra were determined by differences in the main fluorescing pigments: phycoerythrin, phycocyanin and chlorophyll a (Chl a). In the green and brown macroalgae groups, the relative significance of the two emission maxima seems to be related to the thickness of the photosynthetic layer. In thick...... macroalgae, like Codium tomentosum or Fucus vesiculosus, the contribution of the far-red emission fluorescence peak was more significant, most probably due to re-absorption of the emitted red Chl a fluorescence within the dense photosynthetic layer. Similarly, an increase in the number of layers of the thin...

  5. Gaseous nitrous acid (HONO) and nitrogen oxides (NOx) emission from gasoline and diesel vehicles under real-world driving test cycles.

    Science.gov (United States)

    Trinh, Ha T; Imanishi, Katsuma; Morikawa, Tazuko; Hagino, Hiroyuki; Takenaka, Norimichi

    2017-04-01

    Reactive nitrogen species emission from the exhausts of gasoline and diesel vehicles, including nitrogen oxides (NO x ) and nitrous acid (HONO), contributes as a significant source of photochemical oxidant precursors in the ambient air. Multiple laboratory and on-road exhaust measurements have been performed to estimate the NO x emission factors from various vehicles and their contribution to atmospheric pollution. Meanwhile, HONO emission from vehicle exhaust has been under-measured despite the fact that HONO can contribute up to 60% of the total hydroxyl budget during daytime and its formation pathway is not fully understood. A profound traffic-induced HONO to NO x ratio of 0.8%, established by Kurtenbach et al. since 2001, has been widely applied in various simulation studies and possibly linked to under-estimation of HONO mixing ratios and OH radical budget in the morning. The HONO/NO x ratios from direct traffic emission have become debatable when it lacks measurements for direct HONO emission from vehicles upon the fast-changing emission reduction technology. Several recent studies have reported updated values for this ratio. This study has reported the measurement of HONO and NO x emission as well as the estimation of exhaust-induced HONO/NO x ratios from gasoline and diesel vehicles using different chassis dynamometer tests under various real-world driving cycles. For the tested gasoline vehicle, which was equipped with three-way catalyst after-treatment device, HONO/NO x ratios ranged from 0 to 0.95 % with very low average HONO concentrations. For the tested diesel vehicle equipped with diesel particulate active reduction device, HONO/NO x ratios varied from 0.16 to 1.00 %. The HONO/NO x ratios in diesel exhaust were inversely proportional to the average speeds of the tested vehicles. Photolysis of HONO is a dominant source of morning OH radicals. Conventional traffic-induced HONO/NO x ratio of 0.8% has possibly linked to underestimation of the total HONO

  6. Temporal characteristics of atmospheric ammonia and nitrogen dioxide over China based on emission data, satellite observations and atmospheric transport modeling since 1980

    Science.gov (United States)

    Liu, Lei; Zhang, Xiuying; Xu, Wen; Liu, Xuejun; Li, Yi; Lu, Xuehe; Zhang, Yuehan; Zhang, Wuting

    2017-08-01

    China is experiencing intense air pollution caused in large part by anthropogenic emissions of reactive nitrogen (Nr). Atmospheric ammonia (NH3) and nitrogen dioxide (NO2) are the most important precursors for Nr compounds (including N2O5, HNO3, HONO and particulate NO3- and NH4+) in the atmosphere. Understanding the changes in NH3 and NO2 has important implications for the regulation of anthropogenic Nr emissions and is a requirement for assessing the consequence of environmental impacts. We conducted the temporal trend analysis of atmospheric NH3 and NO2 on a national scale since 1980 based on emission data (during 1980-2010), satellite observation (for NH3 since 2008 and for NO2 since 2005) and atmospheric chemistry transport modeling (during 2008-2015).Based on the emission data, during 1980-2010, significant continuous increasing trends in both NH3 and NOx were observed in REAS (Regional Emission inventory in Asia, for NH3 0.17 and for NOx 0.16 kg N ha-1 yr-2) and EDGAR (Emissions Database for Global Atmospheric Research, for NH3 0.24 and for NOx 0.17 kg N ha-1 yr-2) over China. Based on the satellite data and atmospheric chemistry transport model (CTM) MOZART-4 (Model for Ozone and Related chemical Tracers, version 4), the NO2 columns over China increased significantly from 2005 to 2011 and then decreased significantly from 2011 to 2015; the satellite-retrieved NH3 columns from 2008 to 2014 increased at a rate of 2.37 % yr-1. The decrease in NO2 columns since 2011 may result from more stringent strategies taken to control NOx emissions during the 12th Five Year Plan, while no control policy has focused on NH3 emissions. Our findings provided an overall insight into the temporal trends of both NO2 and NH3 since 1980 based on emission data, satellite observations and atmospheric transport modeling. These findings can provide a scientific background for policy makers that are attempting to control atmospheric pollution in China. Moreover, the multiple datasets

  7. Effects of three years of simulated nitrogen deposition on soil nitrogen dynamics and greenhouse gas emissions in a Korean pine plantation of northeast China.

    Science.gov (United States)

    Song, Lei; Tian, Peng; Zhang, Jinbo; Jin, Guangze

    2017-12-31

    Continuously enhanced nitrogen (N) deposition alters the pattern of N and carbon (C) transformations, and thus influences greenhouse gas emissions. It is necessary to clarify the effect of N deposition on greenhouse gas emissions and soil N dynamics for an accurate assessment of C and N budgets under increasing N deposition. In this study, four simulated N deposition treatments (control [CK: no N addition], low-N [L: 20kgNha -1 yr -1 ], medium-N [M: 40kgNha -1 yr -1 ], and high-N [H: 80kgNha -1 yr -1 ]) were operated from 2014. Carbon dioxide, methane and nitrous oxide fluxes were monitored semimonthly, as were soil variables such as temperature, moisture and the concentrations of total dissolved N (TDN), NO 3 - , NO 2 - , NH 4 + , and dissolved organic N (DON) in soil solutions. The simulated N deposition resulted in a significant increase in TDN, NO 3 - and DON concentrations in soil solutions. The average CO 2 emission rate ranged from 222.6mgCO 2 m -2 h -1 in CK to 233.7mgCO 2 m -2 h -1 in the high-N treatment. Three years of simulated N deposition had no effect on soil CO 2 emission, which was mainly controlled by soil temperature. The mean N 2 O emission rate during the whole 3years was 0.02mgN 2 Om -2 h -1 for CK, which increased significantly to 0.05mgN 2 Om -2 h -1 in the high-N treatment. The N 2 O emission rate positively correlated with NH 4 + concentrations, and negatively correlated with soil moisture. The average CH 4 flux during the whole 3years was -0.74μgCH 4 m -2 h -1 in CK, which increased to 1.41μgCH 4 m -2 h -1 in the low-N treatment. CH 4 flux positively correlated with NO 3 - concentrations. These results indicate that short-term N deposition did not affect soil CO 2 emissions, while CH 4 and N 2 O emissions were sensitive to N deposition. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Synthesis of nitrogen- and iron-containing carbon dots, and their application to colorimetric and fluorometric determination of dopamine

    International Nuclear Information System (INIS)

    Wang, Bin; Chen, Yanfen; Wu, Yuanya; Weng, Bo; Liu, Yingshuai; Li, Chang Ming

    2016-01-01

    Nitrogen- and iron-containing carbon dots (N,Fe-CDs) are synthesized by hydrothermal treatment of branched polyethylenimine (BPEI) and hemin at 180 °C. The N,Fe-CDs are mainly doped with nitrogen and trace amounts of iron(III). The N,Fe-CDs also display intrinsic fluorescence with excitation/emission maxima at 365/452 nm and a quantum yield of 27 %. The nanodots are shown to act as peroxidase mimics by catalyzing the oxidation of tetramethylbenzidine (TMB) by hydrogen peroxide to form a blue product whose quantity can be determined by photometry at 652 nm. This was exploited to design colorimetric and fluorometric assays for dopamine (DA). The colorimetric assay is based on the oxidation of DA by H2O2 in presence of the N,Fe-CDs and TMB. It has an instrumental detection limit of 40 nM (at an S/N ratio of 3), and a visual detection limit of 0.4 μM. The fluorometric assay is based on an inner filter effect that is caused by the formation of oxidized TMB which overlaps (and absorbs) the emission of the N,Fe-CDs located at 452 nm. The fluorometric detection limit is as low as 20 nM (at an S/N ratio of 3). (author)

  9. Strategies for decreasing nitrous oxide emissions from agricultural sources

    Energy Technology Data Exchange (ETDEWEB)

    Oenema, O. [AB-DLO, Wageningen (Netherlands)

    1999-08-01

    Following the Kyoto Conference of 1997, declaring the urgency of implementing strategies for decreasing greenhouse gas emissions, there are several valid arguments to examine the opportunities for reducing nitrous oxide emissions from agriculture. This paper provides a review of the state-of-the-art of emission reduction, discusses two strategies for decreasing emissions and identifies various gaps in current knowledge in this field and the need for relevant scientific research. The two strategies discussed are (1) increasing the nitrogen use efficiency toward the goal of lowering total nitrogen input, and (2) decreasing the release of nitrous oxide per unit of nitrogen from the processes of nitrification and denitrification. Increasing nitrogen use efficiency is thought to be the most effective strategy. To that end, the paper discusses several practical actions and measures based on decisions at tactical and operational management levels. Knowledge gaps identified include (1) incomplete understanding of nitrogen cycling in farming systems, (2) incomplete quantitative understanding of emission controlling factors, (3) information gap between science and policy, and (4) information gap between science and practice. Appropriate research needs are suggested for each of these areas. It is suggested that the highest priority should be given to improving the understanding of emission controlling factors in the field and on the farm. 23 refs., 2 figs.

  10. Chiral Recognition by Fluorescence: One Measurement for Two Parameters

    Directory of Open Access Journals (Sweden)

    Shanshan Yu

    2014-01-01

    Full Text Available This outlook describes two strategies to simultaneously determine the enantiomeric composition and concentration of a chiral substrate by a single fluorescent measurement. One strategy utilizes a pseudoenantiomeric sensor pair that is composed of a 1,1′-bi-2-naphthol-based amino alcohol and a partially hydrogenated 1,1′-bi-2-naphthol-based amino alcohol. These two molecules have the opposite chiral configuration with fluorescent enhancement at two different emitting wavelengths when treated with the enantiomers of mandelic acid. Using the sum and difference of the fluorescent intensity at the two wavelengths allows simultaneous determination of both concentration and enantiomeric composition of the chiral acid. The other strategy employs a 1,1′-bi-2-naphthol-based trifluoromethyl ketone that exhibits fluorescent enhancement at two emission wavelengths upon interaction with a chiral diamine. One emission responds mostly to the concentration of the chiral diamine and the ratio of the two emissions depends on the chiral configuration of the enantiomer but independent of the concentration, allowing both the concentration and enantiomeric composition of the chiral diamine to be simultaneously determined. These strategies would significantly simplify the practical application of the enantioselective fluorescent sensors in high-throughput chiral assay.

  11. Metal plasmon-coupled fluorescence imaging and label free coenzyme detection in cells

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jian, E-mail: jian@cfs.bioment.umaryland.edu [Center for Fluorescence Spectroscopy, University of Maryland School of Medicine, Department of Biochemistry and Molecular Biology, 725 West Lombard Street, Baltimore, MD 21201 (United States); Fu, Yi [Center for Fluorescence Spectroscopy, University of Maryland School of Medicine, Department of Biochemistry and Molecular Biology, 725 West Lombard Street, Baltimore, MD 21201 (United States); Li, Ge [Division of Molecular Pathology, Department of Pathology, University of Maryland School of Medicine, 10 South Pine Street, Baltimore, MD 21201 (United States); Zhao, Richard Y. [Division of Molecular Pathology, Department of Pathology, University of Maryland School of Medicine, 10 South Pine Street, Baltimore, MD 21201 (United States); Department of Microbiology-Immunology, University of Maryland School of Medicine, 10 South Pine Street, Baltimore, MD 21201 (United States); Institute of Human Virology, University of Maryland School of Medicine, 10 South Pine Street, Baltimore, MD 21201 (United States)

    2012-08-31

    Highlights: Black-Right-Pointing-Pointer Metal nanoparticle for fluorescence cell imaging. Black-Right-Pointing-Pointer Non-invasive emission detection of coenzyme in cell on time-resolved confocal microscope. Black-Right-Pointing-Pointer Near-field interaction of flavin adenine dinucleotide with silver substrate. Black-Right-Pointing-Pointer Isolation of emissions by coenzymes from cellular autofluorescence on fluorescence cell imaging. -- Abstract: Flavin adenine dinucleotide (FAD) is a key metabolite in cellular energy conversion. Flavin can also bind with some enzymes in the metabolic pathway and the binding sites may be changed due to the disease progression. Thus, there is interest on studying its expression level, distribution, and redox state within the cells. FAD is naturally fluorescent, but it has a modest extinction coefficient and quantum yield. Hence the intrinsic emission from FAD is generally too weak to be isolated distinctly from the cellular backgrounds in fluorescence cell imaging. In this article, the metal nanostructures on the glass coverslips were used as substrates to measure FAD in cells. Particulate silver films were fabricated with an optical resonance near the absorption and the emission wavelengths of FAD which can lead to efficient coupling interactions. As a result, the emission intensity and quantum yield by FAD were greatly increased and the lifetime was dramatically shortened resulting in less interference from the longer lived cellular background. This feature may overcome the technical limits that hinder the direct observation of intrinsically fluorescent coenzymes in the cells by fluorescence microscopy. Fluorescence cell imaging on the metallic particle substrates may provide a non-invasive strategy for collecting the information of coenzymes in cells.

  12. Two-peaked 5-ALA-induced PpIX fluorescence emission spectrum distinguishes glioblastomas from low grade gliomas and infiltrative component of glioblastomas.

    Science.gov (United States)

    Montcel, Bruno; Mahieu-Williame, Laurent; Armoiry, Xavier; Meyronet, David; Guyotat, Jacques

    2013-04-01

    5-ALA-induced protoporphyrin IX (PpIX) fluorescence enables to guiding in intra-operative surgical glioma resection. However at present, it has yet to be shown that this method is able to identify infiltrative component of glioma. In extracted tumor tissues we measured a two-peaked emission in low grade gliomas and in the infiltrative component of glioblastomas due to multiple photochemical states of PpIX. The second emission peak appearing at 620 nm (shifted by 14 nm from the main peak at 634 nm) limits the sensibility of current methods to measured PpIX concentration. We propose new measured parameters, by taking into consideration the two-peaked emission, to overcome these limitations in sensitivity. These parameters clearly distinguish the solid component of glioblastomas from low grade gliomas and infiltrative component of glioblastomas.

  13. Teaching laser-induced fluorescence of plant leaves

    Science.gov (United States)

    Lenk, Sándor; Gádoros, Patrik; Kocsányi, László; Barócsi, Attila

    2016-11-01

    Plants convert carbon dioxide into sugars using the energy of sunlight. Absorbed light unused for conversion is dissipated primarily as heat with a small fraction re-emitted as fluorescence at longer wavelengths. One can use the latter to estimate photosynthetic activity. The illumination of intact leaves with strong light after keeping them in dark for tens of minutes results in a rapid increase followed by a slow decay of fluorescence emission from the fluorophore chlorophyll-a, called the Kautsky effect. This paper describes a laboratory practice that introduces students of physics or engineering into this research field. It begins with the spectral measurement of the fluorescence emitted by a plant leaf upon UV excitation. Then it focuses on the red and far-red components of the fluorescence emission spectrum characteristic to the chlorophyll-a molecule and presents an inexpensive demonstration of the Kautsky effect. As researchers use more complex measurement techniques and tools, the practice ends up with the demonstration of an intelligent fluorosensor, a compact tool developed for plant physiological research and horticulture applications together with a brief interpretation of some important fluorescence parameters.

  14. Teaching laser-induced fluorescence of plant leaves

    International Nuclear Information System (INIS)

    Lenk, Sándor; Gádoros, Patrik; Kocsányi, László; Barócsi, Attila

    2016-01-01

    Plants convert carbon dioxide into sugars using the energy of sunlight. Absorbed light unused for conversion is dissipated primarily as heat with a small fraction re-emitted as fluorescence at longer wavelengths. One can use the latter to estimate photosynthetic activity. The illumination of intact leaves with strong light after keeping them in dark for tens of minutes results in a rapid increase followed by a slow decay of fluorescence emission from the fluorophore chlorophyll -a , called the Kautsky effect. This paper describes a laboratory practice that introduces students of physics or engineering into this research field. It begins with the spectral measurement of the fluorescence emitted by a plant leaf upon UV excitation. Then it focuses on the red and far-red components of the fluorescence emission spectrum characteristic to the chlorophyll -a molecule and presents an inexpensive demonstration of the Kautsky effect. As researchers use more complex measurement techniques and tools, the practice ends up with the demonstration of an intelligent fluorosensor, a compact tool developed for plant physiological research and horticulture applications together with a brief interpretation of some important fluorescence parameters. (paper)

  15. Near-Membrane Refractometry Using Supercritical Angle Fluorescence.

    Science.gov (United States)

    Brunstein, Maia; Roy, Lopamudra; Oheim, Martin

    2017-05-09

    Total internal reflection fluorescence (TIRF) microscopy and its variants are key technologies for visualizing the dynamics of single molecules or organelles in live cells. Yet truly quantitative TIRF remains problematic. One unknown hampering the interpretation of evanescent-wave excited fluorescence intensities is the undetermined cell refractive index (RI). Here, we use a combination of TIRF excitation and supercritical angle fluorescence emission detection to directly measure the average RI in the "footprint" region of the cell during image acquisition. Our RI measurement is based on the determination on a back-focal plane image of the critical angle separating evanescent and far-field fluorescence emission components. We validate our method by imaging mouse embryonic fibroblasts and BON cells. By targeting various dyes and fluorescent-protein chimeras to vesicles, the plasma membrane, as well as mitochondria and the endoplasmic reticulum, we demonstrate local RI measurements with subcellular resolution on a standard TIRF microscope, with a removable Bertrand lens as the only modification. Our technique has important applications for imaging axial vesicle dynamics and the mitochondrial energy state or detecting metabolically more active cancer cells. Copyright © 2017. Published by Elsevier Inc.

  16. Insight into the heterogeneous adsorption of humic acid fluorescent components on multi-walled carbon nanotubes by excitation-emission matrix and parallel factor analysis.

    Science.gov (United States)

    Yang, Chenghu; Liu, Yangzhi; Cen, Qiulin; Zhu, Yaxian; Zhang, Yong

    2018-02-01

    The heterogeneous adsorption behavior of commercial humic acid (HA) on pristine and functionalized multi-walled carbon nanotubes (MWCNTs) was investigated by fluorescence excitation-emission matrix and parallel factor (EEM- PARAFAC) analysis. The kinetics, isotherms, thermodynamics and mechanisms of adsorption of HA fluorescent components onto MWCNTs were the focus of the present study. Three humic-like fluorescent components were distinguished, including one carboxylic-like fluorophore C1 (λ ex /λ em = (250, 310) nm/428nm), and two phenolic-like fluorophores, C2 (λ ex /λ em = (300, 460) nm/552nm) and C3 (λ ex /λ em = (270, 375) nm/520nm). The Lagergren pseudo-second-order model can be used to describe the adsorption kinetics of the HA fluorescent components. In addition, both the Freundlich and Langmuir models can be suitably employed to describe the adsorption of the HA fluorescent components onto MWCNTs with significantly high correlation coefficients (R 2 > 0.94, Padsorption affinity (K d ) and nonlinear adsorption degree from the HA fluorescent components to MWCNTs was clearly observed. The adsorption mechanism suggested that the π-π electron donor-acceptor (EDA) interaction played an important role in the interaction between HA fluorescent components and the three MWCNTs. Furthermore, the values of the thermodynamic parameters, including the Gibbs free energy change (ΔG°), enthalpy change (ΔH°) and entropy change (ΔS°), showed that the adsorption of the HA fluorescent components on MWCNTs was spontaneous and exothermic. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. A novel fluorescence probe based on triphenylamine Schiff base for bioimaging and responding to pH and Fe{sup 3+}

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Lei; Yang, Xiaodong; Chen, Xiuli [School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640 (China); Zhou, Yuping [Guangdong Provincial key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515 (China); Lu, Xiaodan; Yan, Chenggong; Xu, Yikai [Medical Imaging Center, Nanfang Hospital, Southern Medical University, Guangzhou 510515 (China); Liu, Ruiyuan, E-mail: ruiyliu@smu.edu.cn [Guangdong Provincial key Laboratory of New Drug Screening, School of Pharmaceutical Sciences, Southern Medical University, Guangzhou 510515 (China); Qu, Jinqing, E-mail: cejqqu@scut.edu.cn [School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640 (China)

    2017-03-01

    A novel fluorescence probe 1 based on triphenylamine was synthesized and characterized by NMR, IR, high resolution mass spectrometry and elemental analysis. Its fluorescence was quenched when pH below 2. There was a linear relationship between the fluorescence intensity and pH value ranged from 2 to 7. And its fluorescence emission was reversibility in acidic and alkaline solution. Furthermore, it exhibited remarkable selectivity and high sensitivity to Fe{sup 3+} and was able to detect Fe{sup 3+} in aqueous solution with low detection limit of 0.511 μM. Job plot showed that the binding stoichiometry of 1 with Fe{sup 3+} was 1:1. Further observations of {sup 1}H NMR titration suggested that coordination interaction between Fe{sup 3+} and nitrogen atom on C =N bond promoted the intramolecular charge transfer (ICT) or energy transfer process causing fluorescence quenching. Additionally, 1 was also able to be applied for detecting Fe{sup 3+} in living cell and bioimaging. - Graphical abstract: Triphenylamine based fluorescence probe can detect pH and Fe{sup 3+} simultaneously in aqueous solution and be applied for detecting Fe{sup 3+} in living cell and bioimaging. - Highlights: • The fluorescence probe is sensitive to pH in strong acid conditions. • The fluorescence chemosensor can detect pH and Fe{sup 3+} simultaneously. • The recognition is able to carry out in aqueous solution. • The probe can also be applied for detecting Fe{sup 3+} in living cell and bioimaging. • The sensor is synthesized easily with one step.

  18. Characterization of CDOM from urban waters in Northern-Northeastern China using excitation-emission matrix fluorescence and parallel factor analysis.

    Science.gov (United States)

    Zhao, Ying; Song, Kaishan; Li, Sijia; Ma, Jianhang; Wen, Zhidan

    2016-08-01

    Chromophoric dissolved organic matter (CDOM) plays an important role in aquatic systems, but high concentrations of organic materials are considered pollutants. The fluorescent component characteristics of CDOM in urban waters sampled from Northern and Northeastern China were examined by excitation-emission matrix fluorescence and parallel factor analysis (EEM-PARAFAC) to investigate the source and compositional changes of CDOM on both space and pollution levels. One humic-like (C1), one tryptophan-like component (C2), and one tyrosine-like component (C3) were identified by PARAFAC. Mean fluorescence intensities of the three CDOM components varied spatially and by pollution level in cities of Northern and Northeastern China during July-August, 2013 and 2014. Principal components analysis (PCA) was conducted to identify the relative distribution of all water samples. Cluster analysis (CA) was also used to categorize the samples into groups of similar pollution levels within a study area. Strong positive linear relationships were revealed between the CDOM absorption coefficients a(254) (R (2) = 0.89, p CDOM components can be applied to monitor water quality in real time compared to that of traditional approaches. These results demonstrate that EEM-PARAFAC is useful to evaluate the dynamics of CDOM fluorescent components in urban waters from Northern and Northeastern China and this method has potential applications for monitoring urban water quality in different regions with various hydrological conditions and pollution levels.

  19. Multiple-year nitrous oxide emissions from a greenhouse vegetable field in China: Effects of nitrogen management.

    Science.gov (United States)

    Zhang, Jing; Li, Hu; Wang, Yingchun; Deng, Jia; Wang, Ligang

    2018-03-01

    The greenhouse vegetable (GV) field is an important agricultural system in China. It may also be a hot spot of nitrous oxide (N 2 O) emissions. However, knowledge on N 2 O emission from GV fields and its mitigation are limited due to considerable variations of N 2 O emissions. In this study, we performed a multi-year experiment at a GV field in Beijing, China, using the static opaque chamber method, to quantify N 2 O emissions from GV fields and evaluated N 2 O mitigation efficiency of alternative nitrogen (N) managements. The experiment period spanned three rotation periods and included seven vegetable growing seasons. We measured N 2 O emissions under four treatments, including no N fertilizer use (CK), farmers' conventional fertilizer application (FP), reduced N fertilizer rate (R), and R combined with the nitrification inhibitor "dicyandiamide (DCD)" (R+DCD). The seasonal cumulative N 2 O emissions ranged between 2.09 and 19.66, 1.13 and 11.33, 0.94 and 9.46, and 0.15 and 3.27kgNha -1 for FP, R, R+DCD, and CK, respectively. The cumulative N 2 O emissions of three rotational periods varied from 18.71 to 26.58 (FP), 9.58 to 15.96 (R), 7.11 to 13.42 (R+DCD), and 1.66 to 3.73kgNha -1 (CK). The R and R+DCD treatments significantly (Pemissions under FP by 38.1% to 48.8% and 49.5% to 62.0%, across the three rotational periods, although their mitigation efficiencies were highly variable among different vegetable seasons. This study suggests that GV fields associated with intensive N application and frequent flooding irrigation may substantially contribute to the N 2 O emissions and great N 2 O mitigations can be achieved through reasonably reducing the N-fertilizer rate and/or applying a nitrification inhibitor. The large variations in the N 2 O emission and mitigation across different vegetable growing seasons and rotational periods stress the necessity of multi-year observations for reliably quantifying and mitigating N 2 O emissions for GV systems. Copyright © 2017

  20. A sensitive fluorescent sensor of lanthanide ions

    CERN Document Server

    Bekiari, V; Lianos, P

    2003-01-01

    A fluorescent probe bearing a diazostilbene chromophore and a benzo-15-crown-5 ether moiety is a very efficient sensor of lanthanide ions. The ligand emits strong fluorescence only in the presence of specific ions, namely lanthanide ions, while the emission wavelength is associated with a particular ion providing high sensitivity and resolution.

  1. Micellar Enhanced Three-Dimensional Excitation-Emission Matrix Fluorescence for Rapid Determination of Antihypertensives in Human Plasma with Aid of Second-Order Calibration Methods

    Directory of Open Access Journals (Sweden)

    Hai-Yan Fu

    2015-01-01

    Full Text Available A highly sensitive three-dimensional excitation-emission fluorescence method was proposed to determine antihypertensives including valsartan and amlodipine besylate in human plasma with the aid of second-order calibration methods based on parallel factor analysis (PARAFAC and alternating trilinear decomposition (ATLD algorithms. Antihypertensives with weak fluorescent can be transformed into a strong fluorescent property by changing microenvironment in samples using micellar enhanced surfactant. Both the adopted algorithms with second-order advantage can improve the resolution and directly attain antihypertensives concentration even in the presence of potential strong intrinsic fluorescence from human plasma. The satisfactory results can be achieved for valsartan and amlodipine besylate in complicated human plasma. Furthermore, some statistical parameters and figures of merit were evaluated to investigate the performance of the proposed method, and the accuracy and precision of the proposed method were also validated by the elliptical joint confidence region (EJCR test and repeatability analysis of intraday and interday assay. The proposed method could not only light a new avenue to directly determine valsartan or amlodipine besylate in human plasma, but also hold great potential to be extended as a promising alternative for more practical applications in the determination of weak fluorescent drugs.

  2. Measuring the radial density distribution of light emission around the track of fast ions in nitrogen

    International Nuclear Information System (INIS)

    Ibach, T.

    1983-01-01

    For analysing the emission and stopping of ionization electrons (σ-electrons) emitted by fast ions passing through a gas, the radial density distribution of the light emission of the (0,0) transition of two optical bands in nitrogen have been measured. The systems selected for the epxeriments are the 2nd positive system (2.PS) at 337.1 nm primarily excited by low-energy electrons of about 20 eV, and the first negative system (1.NS) at 391.4 nm excited by faster electrons and simultaneous ionization. The equipment developed for the experiments records the light emission with a telescope-type optical arrangement including interference filters, allowing high local resolution and dynamics of the measured range. The measurements have been carried out at pressures between 0.133 and 13.3 mbar, using photons of energies ranging from 270 keV to 2.8 MeV, helium 3 beams of 270 keV/u and 500 keV/u, and neon beams of 270 keV/u. Abel's inversion applied to the distance functions allows calculation of the spatial light emission density which is normalized for a gas density of 1 g/cm 3 . The profiles of the two bands indicate that the σ-electron spectrum gets harder in outward direction. Next to the beam the impact density decreases faster with increasing ion energy than the stopping power (increasing interaction range of the σ-electrons). With photon beams, about half of the whole light emission in the 1. NS, and of the ionization, is induced by primary interactions of the ion beam. This proportion decreases at constant energy per nucleon with increasing atomic number of the ions as compared with the σ-electrons. The primary σ-emission gets harder with higher atomic numbers. (orig./HP) [de

  3. Emission trading in Ontario : Understanding and managing compliance risk

    Energy Technology Data Exchange (ETDEWEB)

    White, A. [Mirant Canada Energy Marketing ltd., Toronto, ON (Canada)

    2002-07-01

    Mirant is one of the top five American energy marketer of power and gas, with more than 20,700 megawatts (MW) of electric generating capacity worldwide, of which 13,600 is in North America. The author presented a chart displaying nitrogen oxide emissions in Ontario, followed by another chart with the emissions of sulphur dioxide also in Ontario. The emission targets for the power sector were reviewed, as were the nitrogen oxide emission limits from 2002 to 2010. The major features of the Ontario legislation were discussed, covering allowance allocation, unlimited banking and limited provisions for credit. Ontario fossil capacity was reviewed, followed by emission allowance allocation. The issues and risks for Independent Power Producers were discussed. They included the emission rate compared to that of the competition, how much the facility was run last year and how much you expect to run it next year, the possibility of buying allowances or credits and at what cost. Looking to the future, the government of Ontario has announced bold actions on industry emissions. The initiatives include consultations, emission limits for both nitrogen oxide and sulphur dioxide from all major industrial emitters, and tighter province-wide targets and timelines for nitrogen oxide and sulphur dioxide. refs., tabs., figs.

  4. Emission trading in Ontario : Understanding and managing compliance risk

    International Nuclear Information System (INIS)

    White, A.

    2002-01-01

    Mirant is one of the top five American energy marketer of power and gas, with more than 20,700 megawatts (MW) of electric generating capacity worldwide, of which 13,600 is in North America. The author presented a chart displaying nitrogen oxide emissions in Ontario, followed by another chart with the emissions of sulphur dioxide also in Ontario. The emission targets for the power sector were reviewed, as were the nitrogen oxide emission limits from 2002 to 2010. The major features of the Ontario legislation were discussed, covering allowance allocation, unlimited banking and limited provisions for credit. Ontario fossil capacity was reviewed, followed by emission allowance allocation. The issues and risks for Independent Power Producers were discussed. They included the emission rate compared to that of the competition, how much the facility was run last year and how much you expect to run it next year, the possibility of buying allowances or credits and at what cost. Looking to the future, the government of Ontario has announced bold actions on industry emissions. The initiatives include consultations, emission limits for both nitrogen oxide and sulphur dioxide from all major industrial emitters, and tighter province-wide targets and timelines for nitrogen oxide and sulphur dioxide. refs., tabs., figs

  5. Protein as a sole source of nitrogen for in vitro grown tobacco plantlets

    Czech Academy of Sciences Publication Activity Database

    Synková, Helena; Hýsková, V.; Garčeková, K.; Křížová, S.; Ryšlavá, H.

    2016-01-01

    Roč. 60, č. 4 (2016), s. 635-644 ISSN 0006-3134 Institutional support: RVO:61389030 Keywords : glutamate-dehydrogenase * inorganic nitrogen * nitrate transport * organic nitrogen * amino-acids * metabolism * seedlings * leaves * roots * assimilation * ammonium * casein * chlorophyll fluorescence * nitrate * photosynthesis Subject RIV: EF - Botanics Impact factor: 1.551, year: 2016

  6. The regulatory role of endogenous iron on greenhouse gas emissions under intensive nitrogen fertilization in subtropical soils of China.

    Science.gov (United States)

    Han, Jiangpei; Shi, Liangsheng; Wang, Yakun; Chen, Zhuowei; Wu, Laosheng

    2018-05-01

    Anaerobic batch experiments were conducted to study the regulatory role of endogenous iron in greenhouse gas emissions under intensive nitrogen fertilization in subtropical soils of China. Fe 2+ , Fe 3+ , and NO 3 - -N dynamics and N 2 O, CH 4 , and CO 2 emissions, as well as the relationships between N fertilizer, endogenous iron, and greenhouse gas emissions were investigated. The emissions of N 2 O increased to different extents from all the test soils by N1 (260 mg N kg -1 ) application compared with N0. After 24 days of anaerobic incubation, the cumulative emissions of N 2 O from red soils in De'an (DR) were significantly higher than that from paddy soils in De'an (DP) and Qujialing (QP) under N1. However, N application enhanced CH 4 and CO 2 emissions from the red soils slightly but inhibited the emissions from paddy soils. The maximal CH 4 and CO 2 emission fluxes occurred in DP soil without N input. Pearson's correlation analysis showed that there were significant correlations (P greenhouse gas emissions mainly through the involvement in denitrification. The proportion of the electrons donated by Fe 2+ used for N 2 O production in denitrification in DP soil was approximately 37.53%. Moreover, positive correlations between Fe 2+ and CH 4 , CO 2 were found in both DR and QP soils, suggesting that endogenous iron might regulate the anaerobic decomposition of organic carbon to CH 4 and CO 2 in the two soils. Soil pH was also an important factor controlling greenhouse gas emissions by affecting endogenous iron availability and C and N transformation processes.

  7. Emissions of forest floor and mineral soil carbon, nitrogen and mercury pools and relationships with fire severity for the Pagami Creek Fire in the Boreal Forest of northern Minnesota

    Science.gov (United States)

    Randall K. Kolka; Brian R. Sturtevant; Jessica R. Miesel; Aditya Singh; Peter T. Wolter; Shawn Fraver; Thomas M. DeSutter; Phil A. Townsend

    2017-01-01

    Forest fires cause large emissions of C (carbon), N (nitrogen) and Hg (mercury) to the atmosphere and thus have important implications for global warming (e.g. via CO2 and N2O emissions), anthropogenic fertilisation of natural ecosystems (e.g. via N deposition), and bioaccumulation of harmful metals in aquatic and...

  8. Flare Temperature and Nitrogen Oxide Emission Reduction and Heat Transfer in the TGMP-314I Steam Boiler Firebox

    Energy Technology Data Exchange (ETDEWEB)

    Makarov, A. N., E-mail: tgtu-kafedra-ese@mail.ru [Tver’ State Technical University (Russian Federation)

    2016-07-15

    Asolution is given to the problem of heat transfer in the firebox of a steam boiler, taking account of the radiation from all quadrillions of atoms constituting the flare. An innovative firebox for a steam boiler is proposed: the lower part of the firebox is a rectangular parallelepiped and the upper part a four-sided pyramid. The calculations show that in the proposed firebox the nonuniformity of the heat-flux distribution is diminished along the height and perimeter of the walls and nitrogen oxide emissions are reduced.

  9. Effects of dietary protease on nitrogen emissions from broiler production: a holistic comparison using Life Cycle Assessment.

    Science.gov (United States)

    Leinonen, Ilkka; Williams, Adrian G

    2015-12-01

    The aim of the study was to quantify the effects of the use of a protease Ronozyme® ProAct in broiler feed on the environmental impacts of broiler and broiler feed production chains. This was done by using a Life Cycle Assessment (LCA) modelling approach with data from trials using both standard soya-based broiler diets and reduced-protein diets with added protease. The results for the feed production chain showed that there was a reduction in all environmental impact categories when protease was used in the diets. The biggest reduction occurred in the category of Global Warming Potential, mainly as a result of decreased carbon dioxide emissions from land use changes related to soya production. In the results for the broiler production chain, there were relatively bigger reductions in Eutrophication Potential and especially in Acidification Potential, mainly as a result of reduced feed protein content and subsequent nitrogen emissions from housing and manure management. The use of protease in the broiler diets reduced the environmental impacts of both feed production and broiler production. The latter is mainly through reduced ammonia emissions, which has substantial benefit per se in the poultry industry. © 2015 Society of Chemical Industry.

  10. Examining Thermally Sprayed Coats By Fluorescence Microscopy

    Science.gov (United States)

    Street, Kenneth W., Jr.; Leonhardt, Todd A.

    1994-01-01

    True flaws distinquished from those induced by preparation of specimens. Fluorescence microscopy reveals debonding, porosity, cracks, and other flaws in specimens of thermally sprayed coating materials. Specimen illuminated, and dye it contains fluoresces, emitting light at different wavelength. Filters emphasize contrast between excitation light and emission light. Specimen viewed directly or photographed on color film.

  11. Laser induced fluorescence of dental caries

    Science.gov (United States)

    Albin, S.; Byvik, C. E.; Buoncristiani, A. M.

    1988-01-01

    Significant differences between the optical spectra taken from sound regions of teeth and carious regions have been observed. These differences appear both in absorption and in laser induced fluorescence spectra. Excitation by the 488 nm line of an argon ion laser beam showed a peak in the emission intensity around 553 nm for the sound dental material while the emission peak from the carious region was red-shifted by approximately 40 nm. The relative absorption of carious region was significantly higher at 488 nm; however its fluorescence intensity peak was lower by an order of magnitude compared to the sound tooth. Implications of these results for a safe, reliable and early detection of dental caries are discussed.

  12. Fluorescence of the 'fire-chaser' beetle Melanophila acuminata

    International Nuclear Information System (INIS)

    Israelowitz, Meir; Rizvi, Syed H.W.; Schroeder, Herbert P. von

    2007-01-01

    Melanophila acuminata beetles are attracted to forest fires over long distances by a pair of specialized infrared sensory organs. To date, there is no knowledge of their ability to detect or emit fluorescent radiation. We studied the Melanophila acuminata infrared sensory organs histologically and by using fluorescent microscopy, acoustic-optic tunable filter microscopy, and two-photon microscopy to identify fluorescence. We found fluorescent absorption at radiation wavelengths of 480 nm and emission at 570 nm. The functional role of this novel fluorescence is, as of yet, unknown but may be applied to species classification, identification and behavioral studies

  13. Characterization of an array of honeys of different types and botanical origins through fluorescence emission based on LEDs.

    Science.gov (United States)

    Lastra-Mejías, Miguel; Torreblanca-Zanca, Albertina; Aroca-Santos, Regina; Cancilla, John C; Izquierdo, Jesús G; Torrecilla, José S

    2018-08-01

    A set of 10 honeys comprising a diverse range of botanical origins have been successfully characterized through fluorescence spectroscopy using inexpensive light-emitting diodes (LEDs) as light sources. It has been proven that each LED-honey combination tested originates a unique emission spectrum, which enables the authentication of every honey, being able to correctly label it with its botanical origin. Furthermore, the analysis was backed up by a mathematical analysis based on partial least square models which led to a correct classification rate of each type of honey of over 95%. Finally, the same approach was followed to analyze rice syrup, which is a common honey adulterant that is challenging to identify when mixed with honey. A LED-dependent and unique fluorescence spectrum was found for the syrup, which presumably qualifies this approach for the design of uncomplicated, fast, and cost-effective quality control and adulteration assessing tools for different types of honey. Copyright © 2018 Elsevier B.V. All rights reserved.

  14. Mercury risk from fluorescent lamps in China: current status and future perspective.

    Science.gov (United States)

    Hu, Yuanan; Cheng, Hefa

    2012-09-01

    Energy-efficient lighting is one of the key measures for addressing electric power shortages and climate change mitigation, and fluorescent lamps are expected to dominate the lighting market in China over the next several years. This review presents an overview on the emissions and risk of mercury from fluorescent lamps during production and disposal, and discusses measures for reducing the mercury risk through solid waste management and source reduction. Fluorescent lamps produced in China used to contain relatively large amounts of mercury (up to 40 mg per lamp) due to the prevalence of liquid mercury dosing, which also released significant amounts of mercury to the environment. Upgrade of the mercury dosing technologies and manufacturing facilities had significantly reduced the mercury contents in fluorescent lamps, with most of them containing less than 10 or 5mg per lamp now. Occupational hygiene studies showed that mercury emissions occurred during fluorescent lamp production, particularly in the facilities using liquid mercury dosing, which polluted the environmental media at and surrounding the production sites and posed chronic health risk to the workers by causing neuropsychological and motor impairments. It is estimated that spent fluorescent lamps account for approximately 20% of mercury input in the MSW in China. Even though recycling of fluorescent lamps presents an important opportunity to capture the mercury they contain, it is difficult and not cost-effective at reducing the mercury risk under the broader context of mercury pollution control in China. In light of the significant mercury emissions associated with electricity generation in China, we propose that reduction of mercury emissions and risk associated with fluorescent lamps should be achieved primarily through lowering their mercury contents by the manufacturers while recycling programs should focus on elemental mercury-containing waste products instead of fluorescent lamps to recapture

  15. Exhaust Fine Particle and Nitrogen Oxide Emissions from Individual Heavy-Duty Trucks at the Port of Oakland

    Science.gov (United States)

    Dallmann, T. R.; Harley, R. A.; Kirchstetter, T.

    2010-12-01

    Heavy-duty (HD) diesel trucks are a source of nitrogen oxide (NOx) emissions as well as primary fine particulate matter (PM2.5) that includes black carbon (BC) as a major component. Heavy-duty trucks contribute significantly to elevated levels of diesel particulate matter found near highways and in communities surrounding major freight-handling facilities. To reduce the air quality impact of diesel engine emissions, the California Air Resources Board has adopted new rules requiring the retrofit or replacement of in-use HD trucks. These rules take effect during 2010 at ports and railyards, and apply to all trucks operating in California by 2014. This study involves on-road measurements of PM2.5, BC, and NOx emission factor distributions from individual HD trucks driving into the Port of Oakland in the San Francisco Bay area. Measurements of exhaust plumes from individual trucks were made using a mobile laboratory equipped with fast time response (1 Hz) PM2.5, BC, NOx, and carbon dioxide (CO2) sensors. The mobile laboratory was stationed on an overpass above an arterial roadway that connects the Port to a nearby highway (I-880). The air sampling inlet was thereby located above the vertical exhaust pipes of HD diesel trucks passing by on the arterial roadway below. Fuel-specific PM2.5, BC, and NOx emission factors for individual trucks were calculated using a carbon balance method in which concentrations of these species in an exhaust plume are normalized to CO2 concentrations. Initial field sampling was conducted in November, 2009 prior to the implementation of new emission rules. Additional emission measurements were made at the same location during June 2010 and emission factor distributions and averages will be compared.

  16. Reproducibility and Reliability of Repeated Quantitative Fluorescence Angiography

    DEFF Research Database (Denmark)

    Nerup, Nikolaj; Knudsen, Kristine Bach Korsholm; Ambrus, Rikard

    2017-01-01

    INTRODUCTION: When using fluorescence angiography (FA) in perioperative perfusion assessment, repeated measures with re-injections of fluorescent dye (ICG) may be required. However, repeated injections may cause saturation of dye in the tissue, exceeding the limit of fluorescence intensity...... that the camera can detect. As the emission of fluorescence is dependent of the excitatory light intensity, reduction of this may solve the problem. The aim of the present study was to investigate the reproducibility and reliability of repeated quantitative FA during a reduction of excitatory light....

  17. Application of thermal-dissociation laser induced fluorescence (TD-LIF to measurement of HNO3, Σalkyl nitrates, Σperoxy nitrates, and NO2 fluxes using eddy covariance

    Directory of Open Access Journals (Sweden)

    D. K. Farmer

    2006-01-01

    Full Text Available Nitrogen exchange between the atmosphere and biosphere directly influences atmospheric composition. While much is known about mechanisms of NO and N2O emissions, instrumentation for the study of mechanisms contributing to exchange of other major nitrogen species is quite limited. Here we describe the application of a new technique, thermal dissociation-laser induced fluorescence (TD-LIF, to eddy covariance measurements of the fluxes of NO2, total peroxy acyl and peroxy nitrates, total alkyl and multifunctional alkyl nitrates, and nitric acid. The technique offers the potential for investigating mechanisms of exchange of these species at the canopy scale over timescales from days to years. Examples of flux measurements at a ponderosa pine plantation in the mid-elevation Sierra Nevada Mountains in California are reported and used to evaluate instrument performance.

  18. Design and implementation of a dual-wavelength intrinsic fluorescence camera system

    Science.gov (United States)

    Ortega-Martinez, Antonio; Musacchia, Joseph J.; Gutierrez-Herrera, Enoch; Wang, Ying; Franco, Walfre

    2017-03-01

    Intrinsic UV fluorescence imaging is a technique that permits the observation of spatial differences in emitted fluorescence. It relies on the fluorescence produced by the innate fluorophores in the sample, and thus can be used for marker-less in-vivo assessment of tissue. It has been studied as a tool for the study of the skin, specifically for the classification of lesions, the delimitation of lesion borders and the study of wound healing, among others. In its most basic setup, a sample is excited with a narrow-band UV light source and the resulting fluorescence is imaged with a UV sensitive camera filtered to the emission wavelength of interest. By carefully selecting the excitation/emission pair, we can observe changes in fluorescence associated with physiological processes. One of the main drawbacks of this simple setup is the inability to observe more than a single excitation/emission pair at the same time, as some phenomena are better studied when two or more different pairs are studied simultaneously. In this work, we describe the design and the hardware and software implementation of a dual wavelength portable UV fluorescence imaging system. Its main components are an UV camera, a dual wavelength UV LED illuminator (295 and 345 nm) and two different emission filters (345 and 390 nm) that can be swapped by a mechanical filter wheel. The system is operated using a laptop computer and custom software that performs basic pre-processing to improve the image. The system was designed to allow us to image fluorescent peaks of tryptophan and collagen cross links in order to study wound healing progression.

  19. Standard reference for instrument response function in fluorescence lifetime measurements in visible and near infrared

    International Nuclear Information System (INIS)

    Chib, Rahul; Shah, Sunil; Gryczynski, Zygmunt; Fudala, Rafal; Borejdo, Julian; Gryczynski, Ignacy; Zelent, Bogumil; Corradini, Maria G; Ludescher, Richard D

    2016-01-01

    Allura red (AR) fluorophore, a common dye in the food industry, displays a broad emission spectrum in water (visible-to-near infrared region of the electromagnetic spectrum) and has a remarkably short fluorescence lifetime of about 10 ps. This short lifetime does not depend on the emission (observation) wavelength. We examined time responses of AR fluorescence across emission wavelengths from 550 nm to 750 nm and found that it is an ideal candidate for impulse response functions in fluorescence lifetime measurements. (technical note)

  20. Fluorescence properties of human teeth and dental calculus for clinical applications

    Science.gov (United States)

    Lee, Yong-Keun

    2015-04-01

    Fluorescent emission of human teeth and dental calculus is important for the esthetic rehabilitation of teeth, diagnosis of dental caries, and detection of dental calculus. The purposes of this review were to summarize the fluorescence and phosphorescence of human teeth by ambient ultraviolet (UV) light, to investigate the clinically relevant fluorescence measurement methods in dentistry, and to review the fluorescence of teeth and dental calculus by specific wavelength light. Dentine was three times more phosphorescent than enamel. When exposed to light sources containing UV components, the fluorescence of human teeth gives them the quality of vitality, and fluorescent emission with a peak of 440 nm is observed. Esthetic restorative materials should have fluorescence properties similar to those of natural teeth. Based on the fluorescence of teeth and restorative materials as determined with a spectrophotometer, a fluorescence parameter was defined. As to the fluorescence spectra by a specific wavelength, varied wavelengths were investigated for clinical applications, and several methods for the diagnosis of dental caries and the detection of dental calculus were developed. Since fluorescent properties of dental hard tissues have been used and would be expanded in diverse fields of clinical practice, these properties should be investigated further, embracing newly developed optical techniques.