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Sample records for additional hono sources

  1. Effects of additional HONO sources on visibility over the North China Plain

    NASA Astrophysics Data System (ADS)

    Li, Ying; An, Junling; Gultepe, Ismail

    2014-09-01

    The objective of the present study was to better understand the impacts of the additional sources of nitrous acid (HONO) on visibility, which is an aspect not considered in current air quality models. Simulations of HONO contributions to visibility over the North China Plain (NCP) during August 2007 using the fully coupled Weather Research and Forecasting/Chemistry (WRF/Chem) model were performed, including three additional HONO sources: (1) the reaction of photo-excited nitrogen dioxide (NO * 2) with water vapor; (2) the NO2 heterogeneous reaction on aerosol surfaces; and (3) HONO emissions. The model generally reproduced the spatial patterns and diurnal variations of visibility over the NCP well. When the additional HONO sources were included in the simulations, the visibility was occasionally decreased by 20%-30% (3-4 km) in local urban areas of the NCP. Monthly-mean concentrations of NO{3/-}, NH{4/+}, SO{4/2-} and PM2.5 were increased by 20%-52% (3-11 μg m-3), 10%-38%, 6%-10%, and 6%-11% (9-17 μg m-3), respectively; and in urban areas, monthly-mean accumulationmode number concentrations (AMNC) and surface concentrations of aerosols were enhanced by 15%-20% and 10%-20%, respectively. Overall, the results suggest that increases in concentrations of PM2.5, its hydrophilic components, and AMNC, are key factors for visibility degradation. A proposed conceptual model for the impacts of additional HONO sources on visibility also suggests that visibility estimation should consider the heterogeneous reaction on aerosol surfaces and the enhanced atmospheric oxidation capacity due to additional HONO sources, especially in areas with high mass concentrations of NO x and aerosols.

  2. Parameterization of HONO sources in Mega-Cities

    NASA Astrophysics Data System (ADS)

    Li, G.; Zhang, R.; Tie, X.; Molina, L. T.

    2013-05-01

    Nitrous acid (HONO) plays an important role in the photochemistry of the troposphere because the photolysis of HONO is a primary source of the hydroxyl radical (OH) in the early morning. However, the formation or sources of HONO are still poorly understood in the troposphere and thence the representation of the HONO sources in chemical transport models (CTMs) is lack of comprehensive consideration. In the present study, the observed HONO, NOx, and aerosols at an urban supersite T0 during the MCMA-2006 field campaign in Mexico City are used to interpret the HONO formation in association with the suggested HONO sources from literature. The HONO source parameterizations are proposed and incorporated into the WRF-CHEM model. Homogeneous sources of HONO include the reaction of NO with OH and excited NO2 with H2O. Four HONO heterogeneous sources are considered: NO2 reaction with semivolatile organics, NO2 reaction with freshly emitted soot, NO2 reaction on aerosol and ground surfaces. Four cases are used in the present study to evaluate the proposed HONO parameterizations during four field campaigns in which HONO measurements are available, including MCMA-2003 and MCMA-2006 (Mexico City Metropolitan Area, Mexico), MIRAGE-2009 (Shanghai, China), and SHARP (Houston, USA). The WRF-CHEM model with the proposed HONO parameterizations performs moderately well in reproducing the observed diurnal variation of HONO concentrations, showing that the HONO parameterizations in the study are reasonable and potentially useful in improving the HONO simulation in CTMs.

  3. Parameterization of HONO sources in Mega-Cities

    NASA Astrophysics Data System (ADS)

    Li, Guohui; Zhang, Renyi; Tie, Xuxie; Molina, Luisa

    2013-04-01

    Nitrous acid (HONO) plays an important role in the photochemistry of the troposphere because the photolysis of HONO is a primary source of the hydroxyl radical (OH) in the early morning. However, the formation or sources of HONO are still poorly understood in the troposphere; hence the representation of the HONO sources in chemical transport models (CTMs) has lack comprehensive consideration. In the present study, the observed HONO, NOx, and aerosols at an urban supersite T0 during the MCMA-2006 field campaign in Mexico City are used to interpret the HONO formation in association with the suggested HONO sources from literature. The HONO source parameterizations are proposed and incorporated into the WRF-CHEM model. Homogeneous sources of HONO include the reaction of NO with OH and excited NO2 with H2O. Four HONO heterogeneous sources are considered: NO2 reaction with semivolatile organics, NO2 reaction with freshly emitted soot, NO2 reaction on aerosol and ground surfaces. Four cases are used in the present study to evaluate the proposed HONO parameterizations during four field campaigns in which HONO measurements are available, including MCMA-2003 and MCMA-2006 (Mexico City Metropolitan Area, Mexico), MIRAGE-2009 (Shanghai, China), and SHARP (Houston, USA). The WRF-CHEM model with the proposed HONO parameterizations performs moderately well in reproducing the observed diurnal variation of HONO concentrations, showing that the HONO parameterizations in the study are reasonable and potentially useful in improving the HONO simulation in CTMs.

  4. Missing gas-phase source of HONO inferred from Zeppelin measurements in the troposphere

    NASA Astrophysics Data System (ADS)

    Li, Xin; Rohrer, Franz; Hofzumahaus, Andreas; Brauers, Theo; Häseler, Rolf; Bohn, Birger; Broch, Sebastian; Fuchs, Hendrik; Gomm, Sebastian; Holland, Frank; Jäger, Julia; Kaiser, Jennifer; Keutsch, Frank N.; Lohse, Insa; Tillmann, Ralf; Wegener, Robert; Wolfe, Glenn M.; Mentel, Thomas F.; Kiendler-Scharr, Astrid; Wahner, Andreas

    2014-05-01

    Nitrous acid (HONO) is an important trace gas in the atmosphere due to its contribution to the cycles of nitrogen oxides (NOX) and hydrogen oxides (HOX). In the past decades, ground-based observations of HONO around the world showed much higher daytime concentrations than can be explained by the known gas-phase chemistry (i.e., HONO + hν → OH + NO, HONO + OH → NO2 + H2O, OH + NO + M → HONO + M). Different light-dependent reactions on ground surfaces have been proposed as additional daytime HONO sources. However, due to lack of measurements, little is known about the concentrations of HONO and its sources in the planetary boundary layer (PBL) at higher altitudes above the earth's surface. The airship Zeppelin NT is an ideal platform to investigate the chemistry and dynamics of the PBL. During the PEGASOS field campaigns in 2012 and 2013, HONO and its gas-phase sources and sinks were measured simultaneously on-board the airship Zeppelin NT, for the lowest 1 km of the PBL. In the upper part of the altitude range during morning hours, when the airmass is still isolated from processes at the earth's surface by the remaining nocturnal boundary layer, we find unexpectedly large concentrations of HONO which can neither be explained by heterogeneous reactions on aerosol and ground surfaces, nor by known gas-phase reactions. Our observations show evidence for an unknown gas-phase light-dependent HONO production which dominates the overall HONO formation in the lower troposphere. This new HONO source requires NOX and possibly OH or HO2 radicals. As a result, the general impact of HONO on the OH formation is likely overestimated.

  5. Review of heterogeneous photochemical reactions of NOy on aerosol - A possible daytime source of nitrous acid (HONO) in the atmosphere.

    PubMed

    Ma, Jinzhu; Liu, Yongchun; Han, Chong; Ma, Qingxin; Liu, Chang; He, Hong

    2013-02-01

    As an important precursor of hydroxyl radical, nitrous acid (HONO) plays a key role in the chemistry of the lower atmosphere. Recent atmospheric measurements and model calculations show strong enhancement for HONO formation during daytime, while they are inconsistent with the known sources in the atmosphere, suggesting that current models are lacking important sources for HONO. In this article, heterogeneous photochemical reactions of nitric acid/nitrate anion and nitrogen oxide on various aerosols were reviewed and their potential contribution to HONO formation was also discussed. It is demonstrated that HONO can be formed by photochemical reaction on surfaces with deposited HNO3, by photocatalytic reaction of NO2 on TiO2 or TiO2-containing materials, and by photochemical reaction of NO2 on soot, humic acids or other photosensitized organic surfaces. Although significant uncertainties still exist in the exact mechanisms and the yield of HONO, these additional sources might explain daytime observations in the atmosphere.

  6. Detailed budget analysis of HONO in central London reveals a missing daytime source

    NASA Astrophysics Data System (ADS)

    Lee, J. D.; Whalley, L. K.; Heard, D. E.; Stone, D.; Dunmore, R. E.; Hamilton, J. F.; Young, D. E.; Allan, J. D.; Laufs, S.; Kleffmann, J.

    2016-03-01

    Measurements of HONO were carried out at an urban background site near central London as part of the Clean air for London (ClearfLo) project in summer 2012. Data were collected from 22 July to 18 August 2014, with peak values of up to 1.8 ppbV at night and non-zero values of between 0.2 and 0.6 ppbV seen during the day. A wide range of other gas phase, aerosol, radiation, and meteorological measurements were made concurrently at the same site, allowing a detailed analysis of the chemistry to be carried out. The peak HONO/NOx ratio of 0.04 is seen at ˜ 02:00 UTC, with the presence of a second, daytime, peak in HONO/NOx of similar magnitude to the night-time peak, suggesting a significant secondary daytime HONO source. A photostationary state calculation of HONO involving formation from the reaction of OH and NO and loss from photolysis, reaction with OH, and dry deposition shows a significant underestimation during the day, with calculated values being close to 0, compared to the measurement average of 0.4 ppbV at midday. The addition of further HONO sources from the literature, including dark conversion of NO2 on surfaces, direct emission, photolysis of ortho-substituted nitrophenols, the postulated formation from the reaction of HO2 × H2O with NO2, photolysis of adsorbed HNO3 on ground and aerosols, and HONO produced by photosensitized conversion of NO2 on the surface increases the daytime modelled HONO to 0.1 ppbV, still leaving a significant missing daytime source. The missing HONO is plotted against a series of parameters including NO2 and OH reactivity (used as a proxy for organic material), with little correlation seen. Much better correlation is observed with the product of these species with j(NO2), in particular NO2 and the product of NO2 with OH reactivity. This suggests the missing HONO source is in some way related to NO2 and also requires sunlight. Increasing the photosensitized surface conversion rate of NO2 by a factor of 10 to a mean daytime first

  7. Missing gas-phase source of HONO inferred from Zeppelin measurements in the troposphere.

    PubMed

    Li, Xin; Rohrer, Franz; Hofzumahaus, Andreas; Brauers, Theo; Häseler, Rolf; Bohn, Birger; Broch, Sebastian; Fuchs, Hendrik; Gomm, Sebastian; Holland, Frank; Jäger, Julia; Kaiser, Jennifer; Keutsch, Frank N; Lohse, Insa; Lu, Keding; Tillmann, Ralf; Wegener, Robert; Wolfe, Glenn M; Mentel, Thomas F; Kiendler-Scharr, Astrid; Wahner, Andreas

    2014-04-18

    Gaseous nitrous acid (HONO) is an important precursor of tropospheric hydroxyl radicals (OH). OH is responsible for atmospheric self-cleansing and controls the concentrations of greenhouse gases like methane and ozone. Due to lack of measurements, vertical distributions of HONO and its sources in the troposphere remain unclear. Here, we present a set of observations of HONO and its budget made onboard a Zeppelin airship. In a sunlit layer separated from Earth's surface processes by temperature inversion, we found high HONO concentrations providing evidence for a strong gas-phase source of HONO consuming nitrogen oxides and potentially hydrogen oxide radicals. The observed properties of this production process suggest that the generally assumed impact of HONO on the abundance of OH in the troposphere is substantially overestimated.

  8. Large mixing ratios of atmospheric nitrous acid (HONO) at Concordia (East Antarctic Plateau) in summer: a strong source from surface snow?

    NASA Astrophysics Data System (ADS)

    Legrand, M.; Preunkert, S.; Frey, M.; Bartels-Rausch, Th.; Kukui, A.; King, M. D.; Savarino, J.; Kerbrat, M.; Jourdain, B.

    2014-09-01

    During the austral summer 2011/2012 atmospheric nitrous acid (HONO) was investigated for the second time at the Concordia site (75°06' S, 123°33' E), located on the East Antarctic Plateau, by deploying a long-path absorption photometer (LOPAP). Hourly mixing ratios of HONO measured in December 2011/January 2012 (35 ± 5.0 pptv) were similar to those measured in December 2010/January 2011 (30.4 ± 3.5 pptv). The large value of the HONO mixing ratio at the remote Concordia site suggests a local source of HONO in addition to weak production from oxidation of NO by the OH radical. Laboratory experiments demonstrate that surface snow removed from Concordia can produce gas-phase HONO at mixing ratios half that of the NOx mixing ratio produced in the same experiment at typical temperatures encountered at Concordia in summer. Using these lab data and the emission flux of NOx from snow estimated from the vertical gradient of atmospheric concentrations measured during the campaign, a mean diurnal HONO snow emission ranging between 0.5 and 0.8 × 109 molecules cm-2 s-1 is calculated. Model calculations indicate that, in addition to around 1.2 pptv of HONO produced by the NO oxidation, these HONO snow emissions can only explain 6.5 to 10.5 pptv of HONO in the atmosphere at Concordia. To explain the difference between observed and simulated HONO mixing ratios, tests were done both in the field and at lab to explore the possibility that the presence of HNO4 had biased the measurements of HONO.

  9. Potential sources of nitrous acid (HONO) and their impacts on ozone: A WRF-Chem study in a polluted subtropical region

    NASA Astrophysics Data System (ADS)

    Zhang, Li; Wang, Tao; Zhang, Qiang; Zheng, Junyu; Xu, Zheng; Lv, Mengyao

    2016-04-01

    Current chemical transport models commonly undersimulate the atmospheric concentration of nitrous acid (HONO), which plays an important role in atmospheric chemistry, due to the lack or inappropriate representations of some sources in the models. In the present study, we parameterized up-to-date HONO sources into a state-of-the-art three-dimensional chemical transport model (Weather Research and Forecasting model coupled with Chemistry: WRF-Chem). These sources included (1) heterogeneous reactions on ground surfaces with the photoenhanced effect on HONO production, (2) photoenhanced reactions on aerosol surfaces, (3) direct vehicle and vessel emissions, (4) potential conversion of NO2 at the ocean surface, and (5) emissions from soil bacteria. The revised WRF-Chem was applied to explore the sources of the high HONO concentrations (0.45-2.71 ppb) observed at a suburban site located within complex land types (with artificial land covers, ocean, and forests) in Hong Kong. With the addition of these sources, the revised model substantially reproduced the observed HONO levels. The heterogeneous conversions of NO2 on ground surfaces dominated HONO sources contributing about 42% to the observed HONO mixing ratios, with emissions from soil bacterial contributing around 29%, followed by the oceanic source (~9%), photochemical formation via NO and OH (~6%), conversion on aerosol surfaces (~3%), and traffic emissions (~2%). The results suggest that HONO sources in suburban areas could be more complex and diverse than those in urban or rural areas and that the bacterial and/or ocean processes need to be considered in HONO production in forested and/or coastal areas. Sensitivity tests showed that the simulated HONO was sensitive to the uptake coefficient of NO2 on the surfaces. Incorporation of the aforementioned HONO sources significantly improved the simulations of ozone, resulting in increases of ground-level ozone concentrations by 6-12% over urban areas in Hong Kong and

  10. Photoenhanced uptakes of NO2 by indoor surfaces: A new HONO source

    NASA Astrophysics Data System (ADS)

    Gligorovski, S.; Bartolomei, V.; Soergel, M.; Gomez Alvarez, E.; Zetzsch, C.; Wortham, H.

    2012-12-01

    Nitrous acid (HONO) is a known household pollutant that can lead to human respiratory tract irritation. HONO acts as the nitrosating agent, e.g. by the formation of the so-called third-hand smoke after wall reactions of HONO with nicotine (1). HONO can be generated indoors directly during combustion processes or indirectly via heterogeneous NO2 reactions with adsorbed water on diverse surfaces (2). Recently a new source was identified as another path of HONO formation in the troposphere (3). Namely, the light-induced heterogeneous reaction of NO2 with adsorbed organics (known as photosensitizers) on various surfaces such as roads, buildings, rocks or plants leads to enhanced HONO production. The detected values of HONO indoors vary in the range between 2 and 25 parts per billion (ppb). However, like outdoors, the processes leading to HONO formation indoors are not completely understood (4). Indoor photolysis radiation sources include exterior sunlight (λ>350 nm) that enters typically through the windows and indoor illumination sources, i.e., rare gas/mercury fluorescent light bulbs and tungsten and tungsten/halogen light bulbs among others. The present work is showing the importance of indoor sources of HONO recently identified or postulated. We have tested a number of common household chemical agents commonly used for cleaning purposes or coatings of domestic surfaces to better identify different indoor HONO sources. We used a heterogeneous flow tube technique to test the HONO production potentials of these household chemical agents under different experimental conditions, namely with and without light and at different relative humidity levels and different NO2 concentrations. We report uptake kinetics measurements of the heterogeneous reaction of gas phase NO2 with lacquer and paint coated on the walls of the reactor. The flow tube was irradiated with four near-ultraviolet (UV) emitting lamps (range of wavelengths 300-420nm). We observed that the heterogeneous

  11. Understanding HONO concentrations, its role as a hydroxyl radical source and the impact on summertime ozone production in London

    NASA Astrophysics Data System (ADS)

    Stone, D. J.; Whalley, L. K.; Hopkins, J. R.; Holmes, R. E.; Lee, J. D.; Hamilton, J. F.; Laufs, S.; Kleffmann, J.; Heard, D. E.

    2014-12-01

    Understanding the chemistry of free-radicals in the atmosphere is necessary to understand the lifetime of primary pollutants and production of secondary pollutants, such as ozone. In the urban environment, field observations of HONO have revealed elevated concentrations persisting throughout the day and subsequent modelling studies have identified HONO as the major OH precursor (e.g. Elshorbany et al. 2009). Attempts to reproduce the strong daytime HONO signature in models, however, have revealed that the currently known chemistry is unable to account for the levels observed. Here we present simultaneous measurements of OH, HO2, RO2 and HONO made during the Clean air for London project in the summer of 2012. HONO concentrations were observed to build up throughout the night, with concentrations exceeding 2ppbV on several nights. Daytime concentrations were lower, but ~ 300 pptv was observed to persist throughout the afternoon. Zero dimensional box modelling studies, constrained with the detailed MCM chemistry and to the measured HONO, suggest that HONO makes up ~85% of the primary OH budget and just over 50% of the total primary radical budget at noon. The model, however, greatly over-predicts the OH concentrations (and HO2 and RO2concentrations) observed. Unconstrained to HONO, the basic model is unable to reproduce the measured HONO concentrations. A source of HONO from the reaction of NO2 with HO2.H2O, as postulated by Li et al. (2014), can enhance HONO concentrations considerably and also reduces the discrepancy between modelled and measured radicals by reducing the fraction of HONO acting as a net radical source. The model still underestimates the observed HONO by ~ 80% at noon, suggesting that this portion of HONO should still be considered as a primary radical source. The net in-situ ozone production estimated from the measured peroxy radical concentrations and their reaction with NO is sufficient to account for the daily increases in ozone that were

  12. Understanding HONO concentrations in London, its role as a hydroxyl radical source and the impact on summertime ozone production

    NASA Astrophysics Data System (ADS)

    Whalley, Lisa; Lee, James; Stone, Daniel; Hamilton, Jacqueline; Holmes, Rachel; Hopkins, James; Laufs, Sebastian; Kleffmann, Jörg; Heard, Dwayne

    2015-04-01

    Understanding the chemistry of free-radicals in the atmosphere is necessary to understand the lifetime of primary pollutants and the production of secondary pollutants, such as ozone and organic aerosol. In the urban environment, field observations of HONO have revealed elevated concentrations persisting throughout the day and subsequent modelling studies have identified HONO as the major OH precursor. Attempts to reproduce the strong daytime HONO signature in models, however, have revealed that the currently known chemistry is unable to account for the levels observed. Here we present simultaneous measurements of OH, HO2, RO2, OH reactivity and HONO made during the Clean Air for London project in the summer of 2012. HONO concentrations were observed to build up throughout the night, with concentrations exceeding 2 ppbV on several nights. Daytime concentrations were lower, but ~ 300 pptv was observed to persist throughout the afternoon. Box modelling studies, using the Master Chemical Mechanism (MCM) and constrained to the measured HONO, suggest that HONO makes up ~85% of the primary OH budget and just under 50% of the total primary radical budget at noon. The model, however, significantly over-predicts the OH concentrations (and HO2 and RO2 concentrations) observed. Unconstrained to HONO, the basic model is unable to reproduce the measured HONO concentrations. A source of HONO from the reaction of NO2 with HO2.H2O, as postulated by Li et al. (Science, 344, 292, 2014), can enhance HONO concentrations considerably and also reduces the discrepancy between modelled and measured radicals by reducing the fraction of HONO acting as a net radical source. With this process included, the model still underestimates the observed HONO by ~ 69% at noon, suggesting that this portion of HONO should still be considered as a primary radical source. The net in-situ ozone production estimated from the measured peroxy radical concentrations and their reaction with NO is sufficient to

  13. HONO and its potential source particulate nitrite at an urban site in North China during the cold season.

    PubMed

    Wang, Liwei; Wen, Liang; Xu, Caihong; Chen, Jianmin; Wang, Xinfeng; Yang, Lingxiao; Wang, Wenxing; Yang, Xue; Sui, Xiao; Yao, Lan; Zhang, Qingzhu

    2015-12-15

    Characteristics and transformation of nitrous acid (HONO) and particulate nitrite were investigated with high time-resolution field measurements at an urban site in Ji'nan, China from Nov. 2013 to Jan. 2014. During the sampling period, averages of 0.35ppbv HONO and 2.08μgm(-3) fine particulate nitrite were observed. HONO and particulate nitrite exhibited similar diurnal variation patterns but differed in the time at which concentration peaks and valleys occurred. Elevated nocturnal HONO concentration peaks were mainly associated with primary emissions from vehicle exhaust and secondary formation via heterogeneous reactions of NO2. In fresh air masses dominated by vehicle emissions, the average HONO/NOx ratio was 0.58%. The nocturnal heterogeneous reactions of NO2 contributed to about half of the elevated HONO concentration peaks, with the conversion rates in the range of 0.05% to 0.96%h(-1). Meanwhile, a large amount of particulate nitrite, which greatly exceeded the concentration of the gas-phase HONO, was also produced through the heterogeneous reactions of NO2. The large yields of particulate nitrite were facilitated by abundant ammonia and particulate cations in urban Ji'nan. Notably, in the daytime, particulate nitrite acted as a potential source of HONO, especially in conditions of low humidity and acidic aerosols, which possibly has subsequent effects on photochemistry in the boundary layer.

  14. The primary and recycling sources of OH during the NACHTT-2011 campaign: HONO as an important OH primary source in the wintertime

    NASA Astrophysics Data System (ADS)

    Kim, Saewung; VandenBoer, Trevor C.; Young, Cora J.; Riedel, Theran P.; Thornton, Joel A.; Swarthout, Bob; Sive, Barkley; Lerner, Brian; Gilman, Jessica B.; Warneke, Carsten; Roberts, James M.; Guenther, Alex; Wagner, Nicholas L.; Dubé, William P.; Williams, Eric; Brown, Steven S.

    2014-06-01

    We present OH observations from Nitrogen, Aerosol Composition, and Halogens on a Tall Tower 2011 (NACHTT-11) held at the Boulder Atmospheric Observatory in Weld County, Colorado. Average OH levels at noon were ~ 2.7 × 106 molecules cm-3 at 2 m above ground level. Nitrous acid (HONO) photolysis was the dominant OH source (80.4%) during this campaign, while alkene ozonolysis (4.9%) and ozone photolysis (14.7%) were smaller contributions to OH production. To evaluate recycling sources of OH from HO2 and RO2, an observationally constrained University of Washington Chemical Mechanism (UWCM) box model (version 2.1) was employed to simulate ambient OH levels over several scenarios. For the base run, not constrained by observed HONO, the model significantly underestimated OH by a factor of 5.3 in the morning (9:00-11:00) and by a factor of 3.2 in the afternoon (13:00-15:00). The results suggest that known chemistry cannot constrain HONO and, subsequently, OH during the observational period. When HONO is constrained in the model by observations (< 50 m), the discrepancy between observation and model simulation improves to a factor of 1.3 in the morning and a factor 1.1 in the afternoon, within the 35% estimated instrumental uncertainty. However, the model produces both a morning and afternoon maximum in OH, in contrast to the observations, which show strong evidence for morning OH production but no distinct morning maximum. Two additional OH sources were also considered, although they do not improve the differences in modeled and measured temporal OH profiles. First, the impact of daytime HONO gradients near the ground surface (< 20 m) was evaluated. Strong HONO gradients were observed between 06:00 and 09:00 MST (mountain standard time), especially within 20 m of the surface. When constrained to HONO observed below 20 m (rather than 50 m), the model produced an even larger morning OH maximum, in contrast to the observations. Second, Cl atoms from ClNO2 photolysis

  15. A comparison of measured HONO uptake and release with calculated source strengths in a heterogeneous forest environment

    NASA Astrophysics Data System (ADS)

    Sörgel, M.; Trebs, I.; Wu, D.; Held, A.

    2015-08-01

    Vertical mixing ratio profiles of nitrous acid (HONO) were measured in a clearing and on the forest floor in a rural forest environment. For the forest floor, HONO was found to predominantly deposit, whereas for the clearing, net deposition dominated only during nighttime and net emissions were observed during daytime. For selected days, net fluxes of HONO were calculated from the measured profiles using the aerodynamic gradient method. The emission fluxes were in the range of 0.02 to 0.07 nmol m-2 s-1 and thus were in the lower range of previous observations. These fluxes were compared to the strengths of postulated HONO sources. Laboratory measurements of different soil samples from both sites revealed an upper limit for soil biogenic HONO emission fluxes of 0.025 nmol m-2 s-1. HONO formation by light-induced NO2 conversion was calculated to be below 0.03 nmol m-2 s-1 for the investigated days, which is comparable to the potential soil fluxes. Due to light saturation at low irradiance, this reaction pathway was largely found to be independent of light intensity, i.e. it was only dependent on ambient NO2. We used three different approaches based on measured leaf nitrate loadings for calculating HONO formation from HNO3 photolysis. While the first two approaches based on empirical HONO formation rates yielded values in the same order of magnitude as the estimated fluxes, the third approach based on available kinetic data of the postulated pathway failed to produce noticeable amounts of HONO. Estimates based on reported cross sections of adsorbed HNO3 indicate that the lifetime of adsorbed HNO3 was only about 15 min, which would imply a substantial renoxification. Although the photolysis of HNO3 was significantly enhanced at the surface, the subsequent light-induced conversion of the photolysis product NO2 did not produce considerable amounts of HONO. Consequently, this reaction might occur via an alternative mechanism. By explicitly calculating HONO formation based

  16. A comparison of measured HONO uptake and release with calculated source strengths in a heterogeneous forest environment

    NASA Astrophysics Data System (ADS)

    Sörgel, Matthias; Trebs, Ivonne; Wu, Dianming; Held, Andreas

    2015-04-01

    Vertical mixing ratio profiles of nitrous acid (HONO) were measured in a clearing and on the forest floor in a rural forest environment (in the south-east of Germany) by applying a lift system to move the sampling unit of the LOng Path Absorption Photometer (LOPAP) up and down. For the forest floor, HONO was found to be predominantly deposited, whereas net deposition was dominating in the clearing only during nighttime and net emissions were observed during daytime. For selected days, net fluxes of HONO were calculated from the measured profiles using the aerodynamic gradient method. The emission fluxes were in the range of 0.02 to 0.07 nmol m-2 s-1, and, thus were in the lower range of previous observations. These fluxes were compared to the strengths of postulated HONO sources and to the amount of HONO needed to sustain photolysis in the boundary layer. Laboratory measurements of different soil samples from both sites revealed an upper limit for soil biogenic HONO emission fluxes of 0.025 nmol m-2 s-1. HONO formation by light induced NO2 conversion was calculated to be below 0.03 nmol m-2 s-1 for the investigated days, which is comparable to the potential soil fluxes. Due to light saturation at low irradiance, this reaction pathway was largely found to be independent of light intensity, i.e. it was only dependent on ambient NO2. We used three different approaches based on measured leaf nitrate loadings for calculating HONO formation from HNO3 photolysis. While the first two approaches based on empirical HONO formation rates yielded values in the same order of magnitude as the estimated fluxes, the third approach based on available kinetic data of the postulated pathway failed to produce noticeable amounts of HONO. Estimates based on reported cross sections of adsorbed HNO3 indicate that the lifetime of adsorbed HNO3 was only about 15 min, which would imply a substantial renoxification. Although the photolysis of HNO3 was significantly enhanced at the surface, the

  17. ATMOSPHERIC SCIENCE. Response to Comment on "Missing gas-phase source of HONO inferred from Zeppelin measurements in the troposphere".

    PubMed

    Li, Xin; Rohrer, Franz; Hofzumahaus, Andreas; Brauers, Theo; Häseler, Rolf; Bohn, Birger; Broch, Sebastian; Fuchs, Hendrik; Gomm, Sebastian; Holland, Frank; Jäger, Julia; Kaiser, Jennifer; Keutsch, Frank N; Lohse, Insa; Lu, Keding; Tillmann, Ralf; Wegener, Robert; Wolfe, Glenn M; Mentel, Thomas F; Kiendler-Scharr, Astrid; Wahner, Andreas

    2015-06-19

    Ye et al. have determined a maximum nitrous acid (HONO) yield of 3% for the reaction HO2·H2O + NO2, which is much lower than the yield used in our work. This finding, however, does not affect our main result that HONO in the investigated Po Valley region is mainly from a gas-phase source that consumes nitrogen oxides.

  18. Combustion Processes Indoors: a Source of High OH Radical Concentrations Through the Photolysis of Hono

    NASA Astrophysics Data System (ADS)

    Bartolomei, V.; Gomez Alvarez, E.; Glor, M.; Gligorovski, S.; Temime-Roussel, B.; Quivet, E.; Strekowski, R.; Zetzsch, C.; Held, A. B.; Wortham, H.

    2013-12-01

    Hydroxyl radical (OH) is one of the most important oxidant species in the atmosphere controlling its self-oxidizing capacity. The main sources of OH radicals are photolysis of ozone and photolysis of nitrous acid (HONO), among the others. In the indoor air, the ozonolysis of alkenes has been suggested as the main OH formation pathway. The possibility for OH formation through photolytic pathways in the indoor environment has been, up to now, ignored (Gómez Alvarez et al., 2012). Models and indirect measurements to the present time predicted concentrations of OH radicals in the order of 104 -105 cm-3. Recently, by direct measurements we have detected high OH radical concentrations of 1.8 106 cm-3 in a classroom in Marseille and we demonstrated that its main source is the photolysis of HONO (Gómez Alvarez et al., 2013). The concentrations of HONO are quite high indoors, reaching levels in the order of a few tens of ppbV (Gómez Alvarez et al., 2013). This is mainly due to 1) direct combustion sources and 2) heterogeneous reactions of NO2 on the numerous surfaces present in the indoor environment. HONO levels of 30 ppb were measured in a previous campaign carried out in Bayreuth in July 2012 as direct emissions from the combustion of a candle. The combination between so high concentrations of HONO and higher than expected light transmissions indoors (or indoor artificial lighting) could have a significant impact on the OH concentrations indoors which could feasibly become considerably higher than we measured in our school campaign (Gomez Alvarez et al., 2013). In order to evaluate these upper limits under combustion conditions in the indoor environment, we have carried out a campaign in the LOTASC chamber (Bayreuth, Germany). For this aim, the exhaust fumes from the burning of a commonly used domestic candle have been introduced in the chamber. The chamber was irradiated under well research indoor lighting conditions. A thorough characterization of light intensities

  19. Daytime formation of nitrous acid at a coastal remote site in Cyprus indicating a common ground source of atmospheric HONO and NO

    NASA Astrophysics Data System (ADS)

    Meusel, Hannah; Kuhn, Uwe; Reiffs, Andreas; Mallik, Chinmay; Harder, Hartwig; Martinez, Monica; Schuladen, Jan; Bohn, Birger; Parchatka, Uwe; Crowley, John N.; Fischer, Horst; Tomsche, Laura; Novelli, Anna; Hoffmann, Thorsten; Janssen, Ruud H. H.; Hartogensis, Oscar; Pikridas, Michael; Vrekoussis, Mihalis; Bourtsoukidis, Efstratios; Weber, Bettina; Lelieveld, Jos; Williams, Jonathan; Pöschl, Ulrich; Cheng, Yafang; Su, Hang

    2016-11-01

    Characterization of daytime sources of nitrous acid (HONO) is crucial to understand atmospheric oxidation and radical cycling in the planetary boundary layer. HONO and numerous other atmospheric trace constituents were measured on the Mediterranean island of Cyprus during the CYPHEX (CYprus PHotochemical EXperiment) campaign in summer 2014. Average volume mixing ratios of HONO were 35 pptv (±25 pptv) with a HONO / NOx ratio of 0.33, which was considerably higher than reported for most other rural and urban regions. Diel profiles of HONO showed peak values in the late morning (60 ± 28 pptv around 09:00 local time) and persistently high mixing ratios during daytime (45 ± 18 pptv), indicating that the photolytic loss of HONO is compensated by a strong daytime source. Budget analyses revealed unidentified sources producing up to 3.4 × 106 molecules cm-3 s-1 of HONO and up to 2.0 × 107 molecules cm-3 s-1 NO. Under humid conditions (relative humidity > 70 %), the source strengths of HONO and NO exhibited a close linear correlation (R2 = 0.72), suggesting a common source that may be attributable to emissions from microbial communities on soil surfaces.

  20. Continuous measurement of nitrous acid (HONO) in indoor environment using a diffusion scrubber and chemiluminescence method

    NASA Astrophysics Data System (ADS)

    Park, S.; Hong, J.; Lee, J.; Cho, S.

    2006-12-01

    Recent study has demonstrated that the use of combustion appliances in indoor environments, e.g., gas stoves and heaters, results in significant concentrations of NO2 and nitrous acid (HONO). Indoor HONO is formed by both direct emissions from combustion processes and the heterogeneous reaction of NO2 with water vapor on surfaces present indoors. In this study in-situ instrument was constructed for measuring HONO concentration in both indoor and outdoor environments, utilizing diffusion scrubber and peroxynitrite-induced luminol chemiluminescent methods. We measured the HONO concentration under the conditions existing in living room of an apartment, along with NO, NO2, temperature, and relative humidity, to investigate the sources, chemical transformation, and lifetimes of nitrogen oxides and HONO. Some experiments investigated the emissions and transformations of nitrogen species from operation of unvented or vented gas appliance. Measurement data of NO, NO2, and HONO will be reported, and formation pathway of the HONO under the experimental conditions will also be discussed. In addition to measurement of indoor HONO, comparison of HONO measurements by luminol chemiluminescence and annular denuder integrated samples was made in outdoor environment. HONO in ambient air was sampled with annular denuders (Teflon-coated PM2.5 cyclone inlet followed by two Na2CO3-coated denuders coupled in series) operated at 16.7 L/min. Acknowledgement This study was supported by grant No. (# R01-2005-000-10775-0) from the Basic Research Program of the Korea Science and Engineering Foundation (KOSEF).

  1. Fast time response measurements of gaseous nitrous acid using a tunable diode laser absorption spectrometer: HONO emission source from vehicle exhausts

    NASA Astrophysics Data System (ADS)

    Li, Yongquan Q.; Schwab, James J.; Demerjian, Kenneth L.

    2008-02-01

    We present the measurement of gaseous nitrous acid (HONO) using a tunable diode laser absorption spectrometer. This method utilizes one strong absorption feature at 1713.511cm-1, which is free of interference and suitable for ambient HONO measurements. The detection limit for a 1-second integration time is determined to be better than 200 pptv. The measurement method has been demonstrated by sampling room air over an 11-day period. HONO mixing ratios ranged from below the detection limit (<=200 pptv) to 4.8 ppbv, with a mean value of 0.73 ppbv. A number of elevated HONO events lasting from several seconds up to hours were observed and have been associated with roadway traffic adjacent to the building where the measurements were performed. The variation in the ratio of HONO/NOx and its anti-correlation with ambient NOx measurements indicate that the source of HONO in this measurement study is mainly from the direct emission of traffic exhausts and local heterogeneous reactions. The demonstrated application of TDLAS fast response measurement technology is capable of providing new information on the sources and sinks of HONO in the environment.

  2. The Primary and Recycling Sources of OH During the NACHTT-2011 Campaign: HONO as an Important OH Primary Source in the Wintertime

    SciTech Connect

    Kim, S.; VandenBoer, Trevor; Young, Cora; Riedel, Theran; Thornton, Joel A.; Swarthout, Bob; Sive, B.; Lerner, Brian M.; Gilman, Jessica; Warneke, Carsten; Roberts, James M.; Guenther, Alex B.; Wagner, Nicholas; Dube, William P.; Williams, Eric; Brown, Steve

    2014-06-10

    We present OH observation results during the NACHTT-11 field campaign at the Boulder Atmospheric Observatory in Weld County, Colorado. The observed OH levels during the daytime (at noon) were ~ 2.7 × 106 molecules cm-3 at the ground level (2 m above ground level, AGL). HONO and ozone photolysis were the two dominant photochemical OH production pathways during the field campaign. However, alkene ozonolysis, found an important source for OH by two previous winter season OH observations, was a minor contribution to OH primary production (~5 %). To evaluate recycling sources of OH from HO2 and RO2, an observation constrained University of Washington Chemical Mechanism (UWCM) box model is employed to simulated ambient OH levels with different model scenarios. For the base run without constraining observed HONO, the model simulated OH significantly underestimates the observed OH level (20.8 times in the morning and 7.2 times in the daytime). This indicates that the known HONO sources incorporated in the UWCM model cannot explain the observed HONO level. Once HONO is constrained by the observation, the discrepancy between observation and model simulation improves (5.1 times in the morning and 2.1 times in the daytime) but still out of the measurement uncertainty range (35 %). We explore two possible reasons for the observed unexplainably high wintertime OH levels. First, potential roles of Cl atoms produce organic peroxy radicals from the reactions between Cl atmos and alkane compounds. However, the Cl levels during the observation period are estimated very low (~ 103 atoms cm-3) to explain the enhanced OH levels. Second, Impacts of higher HONO levels on the ground was evaluated. Strong HONO gradient towards ground was observed especially during the early morning (6 am to 8 am) was observed and the lowest level available for the HONO observation during the campaign is 5 m AGL. Once we assume the twice of the observed HONO levels averaged between 5 m to 15 m at 2 m AGL

  3. Observation of nitrous acid (HONO) in Beijing, China: Seasonal variation, nocturnal formation and daytime budget.

    PubMed

    Wang, Jiaqi; Zhang, Xiaoshan; Guo, Jia; Wang, Zhangwei; Zhang, Meigen

    2017-02-23

    Seasonal characteristics of atmospheric nitrous acid (HONO) were investigated with high time-resolution field measurements at an urban site of Beijing in four select months (representing four different seasons) from September 2015 to July 2016. The HONO concentrations displayed a pronounced seasonal profile with a maximum in autumn (2.27±1.82ppb) and a minimum in winter (1.05±0.89ppb). Significant diurnal cycles were also observed during the whole campaign. We found that the nighttime build-up of HONO was attributed to the heterogeneous conversion of NO2 on wet surface. The calculated NO2 to HONO conversion frequencies varied from 0.005h(-1) in spring to 0.010h(-1) in summer, with an average value of 0.008h(-1). The seasonality of these conversion frequencies was closely related to the RH levels in different seasons. During daytime, large additional HONO sources were calculated. The noontime additional source was the highest in autumn 3.82ppbh(-1), followed by summer 3.05ppbh(-1), spring 2.63ppbh(-1) and winter 1.30ppbh(-1). Correlation studies between the additional HONO source and related parameters demonstrated that the controlling processes responsible for HONO daytime formation varied in different seasons, and that the photo-enhanced formation on wet surface or the photolysis of adsorbed nitric acid and nitrate could be potential HONO sources in Beijing.

  4. HONO fluxes from soil surfaces: an overview

    NASA Astrophysics Data System (ADS)

    Wu, Dianming; Sörgel, Matthias; Tamm, Alexandra; Ruckteschler, Nina; Rodriguez-Caballero, Emilio; Cheng, Yafang; Pöschl, Ulrich; Weber, Bettina

    2016-04-01

    Gaseous nitrous acid (HONO) contributes up to 80% of atmospheric hydroxyl (OH) radicals and is also linked to health risks through reactions with tobacco smoke forming carcinogens. Field and modeling results suggested a large unknown HONO source in the troposphere during daytime. By measuring near ground HONO mixing ratio, up to 30% of HONO can be released from forest, rural and urban ground as well as snow surfaces. This source has been proposed to heterogeneous reactions of nitrogen dioxide (NO2) on humic acid surfaces or nitric acid photolysis. Laboratory studies showed that HONO emissions from bulk soil samples can reach 258 ng m-2 s-1 (in term of nitrogen), which corresponding to 1.1 × 1012 molecules cm-2 s-1and ˜ 100 times higher than most of the field studies, as measured by a dynamic chamber system. The potential mechanisms for soil HONO emissions include chemical equilibrium of acid-base reaction and gas-liquid partitioning between soil nitrite and HONO, but the positive correlation of HONO fluxes with pH (largest at neutral and slightly alkaline) points to the dominance of the formation process by ammonia-oxidizing bacteria (AOB). In general soil surface acidity, nitrite concentration and abundance of ammonia-oxidizing bacteria mainly regulate the HONO release from soil. A recent study showed that biological soil crusts in drylands can also emit large quantities of HONO and NO, corresponding to ˜20% of global nitrogen oxide emissions from soils under natural vegetation. Due to large concentrations of microorganisms in biological soil crusts, particularly high HONO and NO emissions were measured after wetting events. Considering large areas of arid and arable lands as well as peatlands, up to 70% of global soils are able to emitting HONO. However, the discrepancy between large soil HONO emissions measured in lab and low contributions of HONO flux from ground surfaces in field as well as the role of microorganisms should be further investigated.

  5. Heterogeneous Reactivity of NO2 with Photocatalytic Paints: A Possible Source of Nitrous Acid (HONO) in the Indoor Environment

    NASA Astrophysics Data System (ADS)

    Gligorovski, S.; Bartolomei, V.; Gandolfo, A.; Gomez Alvarez, E.; Kleffmann, J.; Wortham, H.

    2014-12-01

    There is an increasing concern about the indoor air environment, where we spend most of our time. Common methods of improving indoor air quality include controlling pollution sources, increasing ventilation rates or using air purifiers. Photocatalytic remediation technology was suggested as a new possibility to eliminate indoor air pollutants instead of just diluting or disposing them. In the present study, heterogeneous reactions of NO2 were studied on photocatalytic paints containing different size and quantity of TiO2. The heterogeneous reactions were conducted in a photo reactor under simulated atmospheric conditions. The flat pyrex rectangular plates covered with the paint were inserted into the reactor. These plates have been sprayed with the photocatalytic paints at our industrial partner's (ALLIOS) facilities using a high precision procedure that allowed the application of a thin layer of a given thickness of the paint. This allows a homogeneous coverage of the surface with the paint and an accurate determination of the exact amount of paint exposed to gaseous NO2. We demonstrate that the indoor photocatalytic paints which contain TiO2 can substantially reduce the concentrations of nitrogen dioxide (NO2). We show that the efficiency of nitrogen dioxide (NO2) removal increase with the quantity of TiO2 in the range 0 - 7 %. The geometric uptake coefficients increase from 5 · 10-6 to 1.6 · 10-5 under light irradiation of the paints. On the other hand, during the reactions of NO2 with this paint (7 % of TiO2) nitric oxide (NO) and nitrous acid (HONO) are formed. Nitrous acid (HONO) is an important harmful indoor pollutant and its photolysis leads to the formation of highly reactive OH radicals (Gomez Alvarez et al., 2013). Maximum conversion efficiencies of NO2to HONO and NO of 15 % and 33 % were observed at 30 % RH, respectively. Thus, the quantity of TiO2 embedded in the paint is an important parameter regarding the nitrogen oxides (NOx = NO + NO2

  6. ATMOSPHERIC SCIENCE. Comment on "Missing gas-phase source of HONO inferred from Zeppelin measurements in the troposphere".

    PubMed

    Ye, Chunxiang; Zhou, Xianliang; Pu, Dennis; Stutz, Jochen; Festa, James; Spolaor, Max; Cantrell, Christopher; Mauldin, Roy L; Weinheimer, Andrew; Haggerty, Julie

    2015-06-19

    Li et al. (Reports, 18 April 2014, p. 292) proposed a unity nitrous acid (HONO) yield for reaction between nitrogen dioxide and the hydroperoxyl-water complex and suggested a substantial overestimation in HONO photolysis contribution to hydroxyl radical budget. Based on airborne observations of all parameters in this chemical system, we have determined an upper-limit HONO yield of 0.03 for the reaction.

  7. HONO (nitrous acid) emissions from acidic northern soils

    NASA Astrophysics Data System (ADS)

    Maljanen, Marja; Yli-Pirilä, Pasi; Joutsensaari, Jorma; Martikainen, Pertti J.

    2015-04-01

    The photolysis of HONO (nitrous acid) is an important source of OH radical, the key oxidizing agent in the atmosphere, contributing also to removal of atmospheric methane (CH4), the second most important greenhouse gas after carbon dioxide (CO2). The emissions of HONO from soils have been recently reported in few studies. Soil HONO emissions are regarded as missing sources of HONO when considering the chemical reactions in the atmosphere. The soil-derived HONO has been connected to soil nitrite (NO2-) and also directly to the activity of ammonia oxidizing bacteria, which has been studied with one pure culture. Our hypothesis was that boreal acidic soils with high nitrification activity could be also sources of HONO and the emissions of HONO are connected with nitrification. We selected a range of dominant northern acidic soils and showed in microcosm experiments that soils which have the highest nitrous oxide (N2O) and nitric oxide (NO) emissions (drained peatlands) also have the highest HONO production rates. The emissions of HONO are thus linked to nitrogen cycle and also NO and N2O emissions. Natural peatlands and boreal coniferous forests on mineral soils had the lowest HONO emissions. It is known that in natural peatlands with high water table and in boreal coniferous forest soils, low nitrification activity (microbial production of nitrite and nitrate) limits their N2O production. Low availability of nitrite in these soils is the likely reason also for their low HONO production rates. We also studied the origin of HONO in one peat soil with acetylene and other nitrification inhibitors and we found that HONO production is not closely connected to ammonium oxidation (nitrification). Acetylene blocked NO emissions but did not affect HONO or N2O emissions, thus there is another source behind HONO emission from these soils than ammonium oxidation. It is still an open question if this process is microbial or chemical origin.

  8. OH formation by HONO photolysis during the BERLIOZ experiment

    NASA Astrophysics Data System (ADS)

    Alicke, B.; Geyer, A.; Hofzumahaus, A.; Holland, F.; Konrad, S.; PäTz, H. W.; SchäFer, J.; Stutz, J.; Volz-Thomas, A.; Platt, U.

    2003-02-01

    The photolysis of nitrous acid (HONO) in the early morning hours is an important source of OH radicals, the most important daytime oxidizing species. Although the importance of this mechanism has been recognized for many years, no accurate quantification of this OH source is available, and the role of HONO photolysis is often underestimated. We present measurements of HONO and its precursor NO2 by Differential Optical Absorption Spectroscopy (DOAS) during the Berliner Ozonexperiment (BERLIOZ) field campaign in July/August 1998 at Pabstthum near Berlin, Germany. HONO concentrations, formation rates, and simultaneously measured HONO photolysis frequencies are used to calculate the total amount of OH formed by HONO photolysis during a full diurnal cycle. A comparison with the OH formation by photolysis of O3 and HCHO and by the reaction of alkenes with ozone shows that HONO photolysis contributed up to 20% of the total OH formed in a 24 hour period during this campaign. In the morning hours, HONO photolysis was by far the most important OH source during BERLIOZ.

  9. Observations of Nighttime HONO in an Urban Area: Steady States, Dynamic Equilibrium States and Reversible Reservoirs

    NASA Astrophysics Data System (ADS)

    McLaren, Robert; Wojtal, Patryk

    2013-04-01

    Nitrous acid (HONO) is an important radical precursor in the troposphere. Recent consensus suggests that HONO is formed in the dark through the heterogeneous hydrolysis of NO2 on surfaces (2 NO2 + H2O -> HONO + HNO3), largely dominated by hydrolysis on ground surfaces and a smaller contribution from aerosol surfaces. Frequently a steady state of HONO is observed (dHONO/dt ~ 0) at night, which has been ascribed to a balance between heterogeneous formation and dry deposition. The fate of the surface deposited HONO remains an open question with the possibilities including the permanent loss of N(III), accumulation of surface reservoirs of N(III) at night, and/or a full dynamic equilibrium that partitions HONO between the atmosphere and water on the surface. Surface reservoirs of N(III) accumulated at night could act as a source of HONO the next day. Here we report measurements of HONO by DOAS in Toronto for a 1-year period. Of interest is the frequently observed phenomena of a fast approach to a steady state at sunset with rates of increase of d[HONO]/dt = 1.4 ppb/hr (with snow cover) and long periods in which the mixing ratio of HONO is constant with a median level of ~ 1.1 ppb. We discuss these observations in the context of the steady state being attributable to a dynamic equilibrium state.

  10. Photo-induced formation of nitrous acid (HONO) on protein surfaces

    NASA Astrophysics Data System (ADS)

    Meusel, Hannah; Elshorbany, Yasin; Bartels-Rausch, Thorsten; Selzle, Kathrin; Lelieveld, Jos; Ammann, Markus; Pöschl, Ulrich; Su, Hang; Cheng, Yafang

    2014-05-01

    The study of nitrous acid (HONO) is of great interest, as the photolysis of HONO leads to the OH radical, which is the most important oxidant in the troposphere. HONO is directly emitted by combustion of fossil fuel and from soil biogenic nitrite (Su et al., 2011), and can also be formed by gas phase reactions of NO and OH and heterogeneous reactions of NO2. Previous atmospheric measurements have shown unexpectedly high HONO concentrations during daytime. Measured mixing ratios were about one order of magnitude higher than model simulations (Kleffmann et al. 2005, Vogel et al. 2003). The additional daytime source of HONO might be attributed to the photolysis of adsorbed nitric acid or heterogeneous photochemistry of NO2 on organic substrates, such as humic acids or polyphenolic compounds (Stemmler et al., 2006), or indirectly through nitration of phenols and subsequent photolysis of nitrophenols (Sosedova et al., 2011, Bejan et al., 2006). An important reactive surface for the heterogeneous formation of HONO could involve proteins, which are ubiquitous in the environment. They are part of coarse biological aerosol particles like pollen grains, fine particles (fragments of pollen, microorganism, plant debris) and dissolved in rainwater, soil and road dust (Miguel et al. 1999). In this project a thin film of bovine serum albumin (BSA), a model protein with 67 kDa and 21 tyrosine residues per molecule, is irradiated and exposed to nitrogen dioxide in humidified nitrogen. The formation of HONO is measured with long path absorption photometry (LOPAP). The generated HONO is in the range of 100 to 1100 ppt depending on light intensity, NO2 concentration and film thickness. Light induced HONO formation on protein surfaces is stable over the 20-hours experiment of irradiation and exposure. On the other hand, light activated proteins reacting with NO2 form nitrated proteins, as detected by liquid chromatography (LC-DAD). Our experiments on tetranitromethane (TNM) nitrated

  11. Understanding the mechanism behind the nitrous acid (HONO) emissions from the northern soils

    NASA Astrophysics Data System (ADS)

    Bhattarai, Hem Raj; Siljanen, Henri MP; Biasi, Christina; Maljanen, Marja

    2016-04-01

    The interest of the flux of nitrous acid (HONO) from soils has recently increased. HONO is an important source of the oxidant OH- radical in the troposphere and thus results a reduction of the greenhouse gas methane (CH4) in the atmosphere. Soils have been recently found to be potential sources of HONO as these emissions are linked to other nitrogen cycle processes, especially presence of nitrite in soils. Ammonia oxidizing archaea (AOA) and ammonia oxidizing bacteria (AOB) have been suggested as possible yet substantial sources of HONO. Along with soil pH, other physical properties such as C:N, nitrogen availability, soil moisture and temperature may effect HONO emissions. Our preliminary results demonstrate that drained acidic peatlands with a low C:N produces higher NO, N2O and HONO emissions compared to those in pristine peatlands and upland forest soils. This study will identify the hotspots and the process involved in HONO emissions in northern ecosystems. Along with HONO, we will examine the emissions of NO and N2O to quantify the related N-gases emitted. These results will add a new piece of information in our knowledge of the nitrogen cycle. Soil samples will be collected from several boreal and arctic sites in Finland, Sweden and Russia. In the laboratory, soil samples will be manipulated based on previously described soil physical properties. This will be followed by labelling experiment coupled with selective nitrification inhibitor experiment in the soils. Our first hypothesis is that northern ecosystems are sources of HONO. Second, is that the soil properties (C:N ratio, moisture, N-availability, pH) regulate the magnitude of HONO emissions from northern soils. Third is that the first step of nitrification (ammonium oxidation) is the main pathway to produce HONO. This study will show that the northern ecosystems could be sources of HONO and therefore increasing the oxidizing capacity of the lower atmosphere.

  12. HONO emission and production determined from airborne measurements over the Southeast U.S.

    NASA Astrophysics Data System (ADS)

    Neuman, J. A.; Trainer, M.; Brown, S. S.; Min, K.-E.; Nowak, J. B.; Parrish, D. D.; Peischl, J.; Pollack, I. B.; Roberts, J. M.; Ryerson, T. B.; Veres, P. R.

    2016-08-01

    The sources and distribution of tropospheric nitrous acid (HONO) were examined using airborne measurements over the Southeast U.S. during the Southeast Nexus Experiment in June and July 2013. HONO was measured once per second using a chemical ionization mass spectrometer on the NOAA WP-3D aircraft to assess sources that affect HONO abundance throughout the planetary boundary layer (PBL). The aircraft flew at altitudes between 0.12 and 6.4 km above ground level on 18 research flights that were conducted both day and night, sampling emissions from urban and power plant sources that were transported in the PBL. At night, HONO mixing ratios were greatest in plumes from agricultural burning, where they exceeded 4 ppbv and accounted for 2-14% of the reactive nitrogen emitted by the fires. The HONO to carbon monoxide ratio in these plumes from flaming stage fires ranged from 0.13 to 0.52%. Direct HONO emissions from coal-fired power plants were quantified using measurements at night, when HONO loss by photolysis was absent. These direct emissions were often correlated with total reactive nitrogen with enhancement ratios that ranged from 0 to 0.4%. HONO enhancements in power plant plumes measured during the day were compared with a Lagrangian plume dispersion model, showing that HONO produced solely from the gas phase reaction of OH with NO explained the observations. Outside of recently emitted plumes from known combustion sources, HONO mixing ratios measured several hundred meters above ground level were indistinguishable from zero within the 15 parts per trillion by volume measurement uncertainty. The results reported here do not support the existence of a ubiquitous unknown HONO source that produces significant HONO concentrations in the lower troposphere.

  13. Daytime aircraft HONO Measurements over water surface during NOMASS Field Study

    NASA Astrophysics Data System (ADS)

    Ye, C.; Pu, D.; Zhou, X.; Stutz, J.; Mauldin, R.; Cantrell, C. A.; Weinheimer, A. J.; Knapp, D. J.; Haggerty, J. A.; Campos, T. L.; Guenther, A. B.; Kaser, L.; Jensen, J. B.

    2013-12-01

    The NOMDASS (Nitrogen, Oxidants, Mercury and Aerosol Distributions, Sources and Sinks) study is an NSF sponsored airborne experiment, integrating 3 PI-initiated projects: the NAAMEX (The North American Airborne Mercury Experiment), the SOAS (Southern Oxidant and Aerosol Study), and the TROPHONO (TROPospheric HONO) projects. During the NOMDASS field campaign from June 1 to July 15, 2013, based in Smyrna, TN, HONO was measured onboard NCAR's C-130 research aircraft in 19 research flights. In order to study in situ HONO production (i.e., volume production) within air masses, four research flights were designed and conducted over open waters to eliminate potential HONO contributions from ground surface sources. In the 2 inflow flights over the Atlantic Ocean off of the Carolina coast, up to 15 ppt HONO was observed in the clean marine boundary layer (MBL). To sustain the observed levels of HONO, a significant in situ HONO source, at a rate of ~60 ppt hr-1, must exist. Since the NOx mixing ratio was very low, ~ 40 ppt, NOx is unlikely to be a significant HONO precursor in the clean MBL. On the other hand, significant levels of particular nitrate were observed, up to 50 ppt. Photolysis of particulate nitrate may be a significant or even a major HONO source and may be an important re-NOx-ification pathway in this clean and low-NOx marine environment. In a flight over the Gulf of Mexico off of Houston, up to 40 ppt HONO was observed in the Houston plume; in a flight over Lake Michigan, up to 60 ppt HONO was observed in the Chicago plume. At elevated concentrations in urban plumes, HONO may be a significant OH precursor and may play an important role in the photochemical evolution of urban plume.

  14. The Role of Iron-Bearing Minerals in NO2 to HONO Conversion on Soil Surfaces.

    PubMed

    Kebede, Mulu A; Bish, David L; Losovyj, Yaroslav; Engelhard, Mark H; Raff, Jonathan D

    2016-08-16

    Nitrous acid (HONO) accumulates in the nocturnal boundary layer where it is an important source of daytime hydroxyl radicals. Although there is clear evidence for the involvement of heterogeneous reactions of NO2 on surfaces as a source of HONO, mechanisms remain poorly understood. We used coated-wall flow tube measurements of NO2 reactivity on environmentally relevant surfaces (Fe (hydr)oxides, clay minerals, and soil from Arizona and the Saharan Desert) and detailed mineralogical characterization of substrates to show that reduction of NO2 by Fe-bearing minerals in soil can be a more important source of HONO than the putative NO2 hydrolysis mechanism. The magnitude of NO2-to-HONO conversion depends on the amount of Fe(2+) present in substrates and soil surface acidity. Studies examining the dependence of HONO flux on substrate pH revealed that HONO is formed at soil pH < 5 from the reaction between NO2 and Fe(2+)(aq) present in thin films of water coating the surface, whereas in the range of pH 5-8 HONO stems from reaction of NO2 with structural iron or surface complexed Fe(2+) followed by protonation of nitrite via surface Fe-OH2(+) groups. Reduction of NO2 on ubiquitous Fe-bearing minerals in soil may explain HONO accumulation in the nocturnal boundary layer and the enhanced [HONO]/[NO2] ratios observed during dust storms in urban areas.

  15. HONO measurement by differential photolysis

    NASA Astrophysics Data System (ADS)

    Reed, Chris; Brumby, Charlotte A.; Crilley, Leigh R.; Kramer, Louisa J.; Bloss, William J.; Seakins, Paul W.; Lee, James D.; Carpenter, Lucy J.

    2016-06-01

    Nitrous acid (HONO) has been quantitatively measured in situ by differential photolysis at 385 and 395 nm, and subsequent detection as nitric oxide (NO) by the chemiluminescence reaction with ozone (O3). The technique has been evaluated by Fourier transform infrared (FT-IR) spectroscopy to provide a direct HONO measurement in a simulation chamber and compared side by side with a long absorption path optical photometer (LOPAP) in the field. The NO-O3 chemiluminescence technique is robust, well characterized, and capable of sampling at low pressure, whilst solid-state converter technology allows for unattended in situ HONO measurements in combination with fast time resolution and response.

  16. Evidence for a nitrous acid (HONO) reservoir at the ground surface in Bakersfield, CA, during CalNex 2010

    NASA Astrophysics Data System (ADS)

    VandenBoer, T. C.; Markovic, M. Z.; Sanders, J. E.; Ren, X.; Pusede, S. E.; Browne, E. C.; Cohen, R. C.; Zhang, L.; Thomas, J.; Brune, W. H.; Murphy, J. G.

    2014-07-01

    Measurements of HONO(g) and particulate nitrite (NO2-(p)) were made with a modified Ambient Ion Monitor-Ion Chromatography (AIM-IC) instrument during California at the Nexus of Air Quality and Climate 2010 in Bakersfield, CA (CalNex-San Joaquin Valley (SJV)). Observations of gas and particulate matter (PM2.5) water-soluble composition showed accumulation of both species at night, followed by loss the next day. Intercomparison with a Stripping Coil-UV/Vis Absorption Photometer (SC-AP) demonstrated excellent agreement with the AIM-IC HONO(g) measurement (slope = 0.957, R2 = 0.86), and the particulate nitrite observations were validated to be free of known interferences for wet chemical instrumentation. The accumulation of nitrite into particulate matter was found to be enhanced when gaseous mixing ratios of HONO(g) were highest. Reactive uptake of HONO(g) on to lofted dust and the ground surface, forming a reservoir, is a potential mechanism to explain these observations. The AIM-IC HONO(g) measurements were parameterized in a chemical model to calculate the ground surface daytime HONO(g) source strength at 4.5 m above the surface, found to be on the order of 1.27 ppb h-1, to determine the relative importance of a surface reservoir. If all deposited nighttime HONO(g) is reemitted the following day, up to 30% of the daytime HONO(g) source at CalNex-SJV may be accounted for. The observations of HONO(g) and NO2-(p) in Bakersfield, during CalNex, suggest a surface sink and source of HONO(g). Extension of currently accepted unknown daytime HONO(g) source reactions to include a potential surface HONO(g) reservoir should therefore be sound, but quantitation of the relative contributions of each surface source toward daytime HONO(g) production remains to be resolved.

  17. Impact of updated traffic emissions on HONO mixing ratios simulated for urban site in Houston, Texas

    NASA Astrophysics Data System (ADS)

    Czader, B. H.; Choi, Y.; Li, X.; Alvarez, S.; Lefer, B.

    2015-02-01

    Recent measurements in Houston show that HONO traffic emissions are 1.7% of NOx emissions, which is about twice the previously estimated value of 0.8% based on tunnel measurements in 2001. The 0.8% value is widely used to estimate mobile emissions of HONO for air quality modeling applications. This study applies the newly estimated HONO / NOx ratio in the WRF-SMOKE-CMAQ modeling system and estimates the impact of higher HONO traffic emissions on its mixing ratios. Since applied emission inventory resulted in overestimates of NOx mixing ratios and because HONO emissions and chemical formation depend on the magnitude of NOx, thus, before proceeding with HONO emission modifications emissions of NOx were adjusted to reflect current emission trends. The modeled mixing ratios of NOx were evaluated against measured data from a number of sites in the Houston area. Overall, the NOx mean value dropped from 11.11 ppbv in the base case to 7.59 ppbv in the NOx-adjusted case becoming much closer to the observed mean of 7.76 ppbv. The index of agreement (IOA) is improved in the reduced NOx case (0.71 vs. 0.75) and the absolute mean error (AME) is lowered from 6.76 to 4.94. The modeled mixing ratios of HONO were evaluated against the actual observed values attained at the Moody Tower in Houston. The model could not reproduce the morning HONO peaks when the low HONO / NOx ratio of 0.008 was used to estimate HONO emissions. Doubling HONO emissions from mobile sources resulted in higher mixing ratios, and the mean value increased from 0.30 to 0.41 ppbv becoming closer to the observed mean concentrations of 0.69 but still low; AME was slightly reduced from 0.46 to 0.43. IOA for simulation that used the 2001 emission values is 0.63 while for simulation with higher HONO emission it increased to 0.70. Increased HONO emissions from mobile sources resulted in a 14% increase in OH during morning time at the location of the Moody Tower and 3% when averaged over an urban area. The increase

  18. Impact of updated traffic emissions on HONO mixing ratios simulated for urban site in Houston, Texas

    NASA Astrophysics Data System (ADS)

    Czader, B. H.; Choi, Y.; Li, X.; Alvarez, S.; Lefer, B.

    2014-08-01

    Recent measurements in Houston show that HONO traffic emissions are 1.7% of NOx emissions which is about twice the previously estimated value of 0.8% based on tunnel measurements in 2001. The 0.8% value is widely used to estimate mobile emissions of HONO for air quality modeling applications. This study applies the newly estimated HONO/NOx ratio in the WRF-SMOKE-CMAQ modeling system and estimates the impact of higher HONO traffic emissions on its mixing ratios. Since applied emission inventory resulted in overestimates of NOx mixing ratios and because HONO emissions and chemical formation depends on the magnitude of NOx, thus, before proceeding with HONO emission modifications emissions of NOx were adjusted to reflect current emission trends. The modeled mixing ratios of NOx were evaluated against measured data from a number of sites in the Houston area. Overall, the NOx mean value dropped from 11.11 ppbv in the base case to 7.59 ppbv in the NOx adjusted case becoming much closer to the observed mean of 7.76 ppbv. The Index of Agreement (IOA) is improved in the reduced NOx case (0.71 vs. 0.75) and the Absolute Mean Error (AME) is lowered from 6.76 to 4.94. The modeled mixing ratios of HONO were evaluated against the actual observed values attained at the Moody Tower in Houston. The model could not reproduce the morning HONO peaks when the low HONO/NOx ratio of 0.008 was used to estimate HONO emissions. Doubling HONO emissions from mobile sources resulted in higher mixing ratios, the mean value increased from 0.30 to 0.41 ppbv becoming closer to the observed mean concentrations of 0.69 but still low; AME was slightly reduced from 0.46 to 0.43. IOA for simulation that used the 2001 emission values is 0.63 while for simulation with higher HONO emission it increased to 0.70. Increased HONO emissions impacted OH mixing ratio, up to about 6% increase was found during morning and mid-day hours. The impact on ozone is marginal. This study results sheds light on the

  19. Quantum chemical study of the O 3-HONO complex

    NASA Astrophysics Data System (ADS)

    Roohi, Hossein; Ashuri, Masomeh

    2009-07-01

    Gas phase hydrogen-bonded isomers of the O 3-HONO complex have been investigated by means of DFT(B3LYP), MP2, MP4(SDTQ), CCSD(T) and QCISD(T) methods in conjunction with the 6-311++G(2d,2p), 6-311++G(df,pd), AUG-cc-pVDZ and AUG-cc-pVTZ basis sets. Ten isomers were found for the O 3-HONO complex. The O⋯H and O⋯O interactions are predicted that participate in the formation of non-planar ring structure of the most stable isomer. The AIM calculations reveal that the O⋯H interaction in the most stable complex is stronger than others. In addition, both O⋯H and O⋯O interactions in O 3-HONO complexes are electrostatic in nature.

  20. The Role of Iron-Bearing Minerals in NO 2 to HONO Conversion on Soil Surfaces

    SciTech Connect

    Kebede, Mulu A.; Bish, David L.; Losovyj, Yaroslav; Engelhard, Mark H.; Raff, Jonathan D.

    2016-08-16

    Nitrous acid (HONO) accumulates in the nocturnal boundary layer where it is an important source of daytime hydroxyl radicals. Although there is clear evidence for the involvement of heterogeneous reactions of NO2 on surfaces as a source of HONO, mechanisms remain poorly understood. We used coated-wall flow tube measurements of NO2 reactivity on environmentally relevant surfaces [Fe (hydr)oxides, clay minerals, and soil from Arizona and the Saharan Desert] and detailed mineralogical characterization of substrates to show that reduction of NO2 by Fe-bearing minerals in soil can be a more important source of HONO than the putative NO2 hydrolysis mechanism. The magnitude of NO2-to-HONO conversion depends on the amount of Fe2+ present in substrates and soil surface acidity. Studies examining the dependence of HONO flux on substrate pH revealed that HONO is formed at soil pH < 5 from the reaction between NO2 and Fe2+(aq) present in thin films of water coating the surface, whereas in the range of pH 5–8 HONO stems from reaction of NO2 with structural iron or surface complexed Fe2+ followed by protonation of nitrite via surface Fe-OH2+ groups. Reduction of NO2 on ubiquitous Fe-bearing minerals in soil may explain HONO accumulation in the nocturnal boundary layer and the enhanced [HONO]/[NO2] ratios observed during dust storms in urban areas.

  1. Observations of Nighttime HONO over Snow in a Polluted Urban Area: Evidence of an Equilibrium State?

    NASA Astrophysics Data System (ADS)

    Wojtal, P. R.; McLaren, R.

    2012-12-01

    Nitrous acid (HONO) is an important radical precursor in the troposphere. Recent literature consensus suggests that the dark formation of HONO is through the heterogeneous hydrolysis of NO2 on surfaces largely dominated by hydrolysis on ground surfaces and a smaller contribution from aerosol surfaces. Frequently at night, a steady state of HONO is observed (dHONO/dt ~ 0), which has been ascribed to a balance between heterogeneous formation and dry deposition, both at the surface. The fate of the surface deposited HONO remains an open question; with the possibilities including the accumulation of surface reservoirs of nitrite at night and/or a full dynamic equilibrium that partitions HONO between the atmosphere and the surface. Surface reservoirs of nitrite accumulated at night could potentially act as a source of daytime HONO the next day with several release mechanisms possible. In an effort to shed light on these processes, we made daily measurements of HONO by differential optical absorption spectroscopy at York University, Toronto for a 1-year period, including periods of snow accumulation at the surface. Our hypothesis is that during periods of snow coverage, the urban area behaves as a truly aqueous environment, similar to a body of water. Of interest is the frequently observed phenomena of a fast approach to a steady state at sunset with rates of increase of d[HONO]/dt = 2.0 ppb/hr, and long periods in which the mixing ratio of HONO is constant at a median level of ~ 1.1 ppb. We discuss these observations in the context of the steady state being better described as a dynamic equilibrium state.

  2. Atmospheric HONO and NO2 measurement based on a broadband cavity enhanced UV-LED spectrometer

    NASA Astrophysics Data System (ADS)

    Wu, Tao; Zha, Qiaozhi; Chen, Weidong; Xu, Zheng; Wang, Tao; He, Xingdao

    2015-04-01

    Nitrous acid (HONO) is a key component in tropospheric oxidant chemistry due to its contribution to the cycles of nitrogen oxides (NOx) and hydrogen oxides (HOx). Though numerous laboratory, field, and modeling studies were performed to explain the observed HONO concentrations in the atmosphere, the knowledge of atmospheric HONO chemistry is still not well understood and sometimes controversial [1]. Accurate measurements of HONO and its precursors with high precision should aid in understanding the HONO chemistry. In this paper we report on the measurements of HONO and NO2 concentrations at a suburban site of Tung Chung in Hong Kong during a field intercomparison campaign using a broadband cavity enhanced UV-LED spectrometer. 1σ detection limits of 0.3 ppbv for HONO and 1 ppbv for NO2 were achieved with an optimum acquisition time of 120 s. The measured HONO and NO2 concentrations were compared with the data from commercial HONO (LOPAP) and NO2 (NOX-analyzer) measurement instrument. Typical diurnal pattern of HONO have been observed and the potential formation sources have been analyzed [2]. Acknowledgements The supported by National Natural Science Foundation of China (No. 41265011), Educational Commission of Jiangxi Province of China (No.GJJ14548) and Environment and Conservation Fund of the Hong Kong Special Administrative Region (No. 7/2009). The support of the IRENI program of the Région Nord-Pas de Calaisn, is acknowledged. References [1] W. Chen, R. Maamary, X. Cui, T. Wu, E. Fertein, D. Dewaele, F. Cazier, Q. Zha, Z. Xu, T. Wang, Y. Wang, W. Zhang, X. Gao, W. Liu, F. Dong, 'Photonic Sensing of Environmental Gaseous Nitrous Acid (HONO): Opportunities and Challenges' in The Wonder of Nanotechnology: Quantum Optoelectronic Devices and Applications, M. Razeghi. L. Esaki, and K. von Klitzing, Eds., SPIE Press, Bellingham, WA, 2013, pp. 693-737 [2] T. Wu, Q. Zha, W. Chen, Z. XU, T. Wang, X. He, 'Development and deployment of a cavity enhanced UV

  3. Revisiting Nitrous Acid (HONO) Emission from On-road Vehicles: A Tunnel Study with a Mixed Fleet.

    PubMed

    Liang, Yutong; Zha, Qiaozhi; Wang, Weihao; Cui, Long; Lui, Ka Hei; Ho, Kin Fai; Wang, Zhe; Lee, Shun-Cheng; Wang, Tao

    2017-02-21

    Nitrous acid (HONO) is an important precursor of OH radicals in the atmosphere. In urban areas, emissions from vehicles are the main source of air pollutants including reactive nitrogen. Previously reported emission ratios of HONO (HONO/NOx) from vehicles were measured in the late 1990s which needs to be updated due to the significant changes in emission control technologies. We measured the emission ratio of a fleet of vehicles (38% diesel on average) from 11 to 21 March, 2015 in a road tunnel in Hong Kong. The emission ratio 1.24% (± 0.35%) obtained is greater than the commonly adopted 0.8% or 0.3%. The elevated emission ratio is found to be related to the presence of vehicles equipped with Diesel Particle Filters (DPFs). Positive correlation between HONO and Black Carbon (BC) shows that HONO and BC were emitted together, while the lack of correlation or even anti-correlation between HONO/NOx and BC indicates that the BC-mediated conversion of NO2 to HONO in the dark was insignificant in the immediate vicinity of the emission sources. Implications Vehicular emission is a key source for HONO in the urban atmosphere. However, the most commonly used emission ratio HONO/NOx in modeling studies were measured more than 15 years ago. Our tunnel study suggests that a mixed fleet nowadays has a higher emission ratio, possibly because of the Diesel Particle Filter (DPF) retrofit program and the growing share of Euro IV or more advanced diesel vehicles. Our study also provides new insight into the role of Black Carbon in HONO formation from vehicles.

  4. Formation of indoor nitrous acid (HONO) by light-induced NO2 heterogeneous reactions with white wall paint.

    PubMed

    Bartolomei, Vincent; Sörgel, Matthias; Gligorovski, Sasho; Alvarez, Elena Gómez; Gandolfo, Adrien; Strekowski, Rafal; Quivet, Etienne; Held, Andreas; Zetzsch, Cornelius; Wortham, Henri

    2014-01-01

    Gaseous nitrogen dioxide (NO2) represents an oxidant that is present in relatively high concentrations in various indoor settings. Remarkably increased NO2 levels up to 1.5 ppm are associated with homes using gas stoves. The heterogeneous reactions of NO2 with adsorbed water on surfaces lead to the generation of nitrous acid (HONO). Here, we present a HONO source induced by heterogeneous reactions of NO2 with selected indoor paint surfaces in the presence of light (300 nm<λ<400 nm). We demonstrate that the formation of HONO is much more pronounced at elevated relative humidity. In the presence of light (5.5 W m(-2)), an increase of HONO production rate of up to 8.6·10(9) molecules cm(-2) s(-1) was observed at [NO2]=60 ppb and 50% relative humidity (RH). At higher light intensity of 10.6 (W m(-2)), the HONO production rate increased to 2.1·10(10) molecules cm(-2) s(-1). A high NO2 to HONO conversion yield of up to 84% was observed. This result strongly suggests that a light-driven process of indoor HONO production is operational. This work highlights the potential of paint surfaces to generate HONO within indoor environments by light-induced NO2 heterogeneous reactions.

  5. Gaseous nitrous acid (HONO) and nitrogen oxides (NOx) emission from gasoline and diesel vehicles under real-world driving test cycles.

    PubMed

    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 (NOx) 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 NOx 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 NOx 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/NOx 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 NOx emission as well as the estimation of exhaust-induced HONO/NOx 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/NOx 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/NOx ratios varied from 0.16 to 1.00 %. The HONO/NOx ratios in diesel exhaust were inversely proportional to the average speeds of the tested vehicles.

  6. Global and Regional Impacts of HONO on the Chemical Composition of Clouds and Aerosols

    NASA Technical Reports Server (NTRS)

    Elshorbany, Y. F.; Crutzen, P. J.; Steil, B.; Pozzer, A.; Tost, H.; Lelieveld, J.

    2014-01-01

    Recently, realistic simulation of nitrous acid (HONO) based on the HONO / NOx ratio of 0.02 was found to have a significant impact on the global budgets of HOx (OH + HO2) and gas phase oxidation products in polluted regions, especially in winter when other photolytic sources are of minor importance. It has been reported that chemistry-transport models underestimate sulphate concentrations, mostly during winter. Here we show that simulating realistic HONO levels can significantly enhance aerosol sulphate (S(VI)) due to the increased formation of H2SO4. Even though in-cloud aqueous phase oxidation of dissolved SO2 (S(IV)) is the main source of S(VI), it appears that HONO related enhancement of H2O2 does not significantly affect sulphate because of the predominantly S(IV) limited conditions, except over eastern Asia. Nitrate is also increased via enhanced gaseous HNO3 formation and N2O5 hydrolysis on aerosol particles. Ammonium nitrate is enhanced in ammonia-rich regions but not under ammonia-limited conditions. Furthermore, particle number concentrations are also higher, accompanied by the transfer from hydrophobic to hydrophilic aerosol modes. This implies a significant impact on the particle lifetime and cloud nucleating properties. The HONO induced enhancements of all species studied are relatively strong in winter though negligible in summer. Simulating realistic HONO levels is found to improve the model measurement agreement of sulphate aerosols, most apparent over the US. Our results underscore the importance of HONO for the atmospheric oxidizing capacity and corroborate the central role of cloud chemical processing in S(IV) formation

  7. Global and Regional Impacts of HONO on the Chemical Composition of Clouds and Aerosols

    NASA Technical Reports Server (NTRS)

    Elshorbany, Y. F.; Crutzen, P. J.; Steil, B.; Pozzer, A.; Tost, H.; Lelieveld, J.

    2014-01-01

    Recently, realistic simulation of nitrous acid (HONO) based on the HONO/NO(sub x) ratio of 0.02 was found to have a significant impact on the global budgets of HO(sub x) (OH + HO2) and gas phase oxidation products in polluted regions, especially in winter when other photolytic sources are of minor importance. It has been reported that chemistry-transport models underestimate sulphate concentrations, mostly during winter. Here we show that simulating realistic HONO levels can significantly enhance aerosol sulphate (S(VI)) due to the increased formation of H2SO4. Even though in-cloud aqueous phase oxidation of dissolved SO2 (S(IV)) is the main source of S(VI), it appears that HONO related enhancement of H2O2 does not significantly affect sulphate because of the predominantly S(IV) limited conditions, except over eastern Asia. Nitrate is also increased via enhanced gaseous HNO3 formation and N2O5 hydrolysis on aerosol particles. Ammonium nitrate is enhanced in ammonia-rich regions but not under ammonia-limited conditions. Furthermore, particle number concentrations are also higher, accompanied by the transfer from hydrophobic to hydrophilic aerosol modes. This implies a significant impact on the particle lifetime and cloud nucleating properties. The HONO induced enhancements of all species studied are relatively strong in winter though negligible in summer. Simulating realistic HONO levels is found to improve the model measurement agreement of sulphate aerosols, most apparent over the US. Our results underscore the importance of HONO for the atmospheric oxidizing capacity and corroborate the central role of cloud chemical processing in S(IV) formation.

  8. SO2 Initiates the Efficient Conversion of NO2 to HONO on MgO Surface.

    PubMed

    Ma, Qingxin; Wang, Tao; Liu, Chang; He, Hong; Wang, Zhe; Wang, Weihao; Liang, Yutong

    2017-04-04

    Nitrous acid (HONO) is an important source of hydroxyl radical (OH) that determines the fate of many chemically active and climate relevant trace gases. However, the sources and the formation mechanisms of HONO remain poorly understood. In this study, the effect of SO2 on the heterogeneous reactions of NO2 on MgO as a mineral dust surrogate was investigated. The reactivity of MgO to NO2 is weak, while coexisting SO2 can increase the uptake coefficients of NO2 on MgO by 2-3 orders of magnitude. The uptake coefficients of NO2 on SO2-aged MgO are independent of NO2 concentrations in the range of 20-160 ppbv and relative humidity (0-70%RH). The reaction mechanism was demonstrated to be a redox reaction between NO2 and surface sulfite. In the presence of SO2, NO2 was reduced to nitrite under dry conditions, which could be further converted to gas-phase HONO in humid conditions. These results suggest that the reductive effect of SO2 on the heterogeneous conversion of NO2 to HONO may have a significant contribution to the unknown sources of HONO observed in polluted areas (for example, in China).

  9. The Reduction of HNO3 to HONO by Volatile Organic Compounds Associated with Rush Hour Traffic

    NASA Astrophysics Data System (ADS)

    Rutter, A. P.; Malloy, Q.; Scheuer, E.; Gutierrez, C.; Calzada, M.; Dibb, J. E.; Griffin, R. J.

    2012-12-01

    Nitrous acid (HONO) is an important source of OH radicals in urban environments. However, the sources of HONO are not completely understood, which makes modeling urban atmospheric chemistry difficult. During a previous field study in Houston, TX a correlation was observed between increases in HONO and organic aerosol freshly emitted by motor vehicle traffic during morning rush hours (Ziemba et al., 2010). This source of HONO could not be explained by primary HONO emissions, and the hypothesis was drawn that the HONO was being formed from the reduction of HNO3 by the organic aerosols emitted by motor vehicles. To test this hypothesis, nitric acid (HNO3) was combined in a flow tube with aerosols made from automobile engine oil, which were used as a model for the organic aerosols emitted by rush hour traffic. Reduction of the HNO3 to HONO was observed, although the reaction was found to occur with the volatile organic carbon compounds (VOCs) found in the aerosol vapor, and not the particle surfaces. To explore this further Teflon raschig rings were added to the flow tube to increase surface area but the reaction was not enhanced, confirming the reaction to be homogeneous. The HONO formation observed ranged between 0.1 and 0.5 ppb hr-1 with a mean of 0.3±0.1 ppb hr-1, for typical nitric acid concentrations of 4-5 ppb and estimated concentrations of the reactive components in the engine oil vapor of between 200 and 300 ppt. The observations in this study compared well to the cited field study which observed formation rates between 0.05 and 0.5 ppb hr-1 with an average of 0.3±0.15 ppb hr-1. Water vapor was found to decrease the HONO formation rate by 0.1 ppb hr-1 for every1% of increase in the water mixing ratio. Reference Ziemba L.D., Dibb J.E., Griffin R.J., Anderson C.H., Whitlow S.I., Lefer B.L., Rappenglueck B., and Flynn J. (2010) Heterogeneous conversion of nitric acid to nitrous acid on the surface of primary organic aerosol in an urban atmosphere. Atmospheric

  10. The Exchange of Soil Nitrite and Atmospheric HONO: a Missing Process in the Nitrogen Cycle and Atmospheric Chemistry

    NASA Astrophysics Data System (ADS)

    Cheng, Yafang; Su, Hang; Oswald, Robert; Behrendt, Thomas; Trebs, Ivonne; Meixner, Franz X.; Andreae, Meinrat O.; Pöschl, Ulrich

    2013-04-01

    Hydroxyl radicals (OH) are a key species in atmospheric photochemistry. In the lower atmosphere, up to ~30% of the primary OH radical production is attributed to the photolysis of nitrous acid (HONO), and field observations suggest a large missing source of HONO. The dominant sources of N(III) in soil, however, are biological nitrification and denitrification processes, which produce nitrite ions from ammonium (by nitrifying microbes) as well as from nitrate (by denitrifying microbes). We show that soil nitrite can release HONO and explain the reported strength and diurnal variation of the missing source. We also show that the soil-atmosphere exchange of N(III), though not considered in the N cycle, might result in significant amount of reactive nitrogen emission (comparable to soil NO emissions). Fertilized soils with low pH appear to be particularly strong sources of HONO and OH. Thus, agricultural activities and land-use changes may strongly influence the oxidizing capacity of the atmosphere. Because of the widespread occurrence of nitrite-producing microbes and increasing N and acid deposition, the release of HONO from soil may also be important in natural environments, including forests and boreal regions. In view of the potentially large impact on atmospheric chemistry and global environmental change, we recommend further studies of HONO release from soil nitrite and related processes in the biogeochemical cycling of N in both agricultural and natural environments. Reference: Su, H., Cheng, Y., et al., Soil Nitrite as a Source of Atmospheric HONO and OH Radicals, Science, 333, 1616-1618, 10.1126/science.1207687, 2011. Su, H., et al., The Exchange of Soil Nitrite and Atmospheric HONO: A Missing Process in the Nitrogen Cycle and Atmospheric Chemistry, NATO Science for Peace and Security Series C: Environmental Security, Springer Netherlands, 93-99, 2013.

  11. Uptake of gaseous nitrous acid (HONO) by several plant species

    NASA Astrophysics Data System (ADS)

    Schimang, Ralf; Folkers, Achim; Kleffmann, Jörg; Kleist, Einhard; Miebach, Marco; Wildt, Jürgen

    Uptake of gaseous nitrous acid (HONO) by sunflower ( Heliantus annuus L. var. gigantheus), tobacco ( Nicotiana tabacum L. var. Bel W3), castor ( Rhicinus communis L. var. Carmencita), and birch ( Betula pendula L.) was studied under controlled conditions in a continuously stirred tank reactor. Exposing plants to HONO at concentrations between 60 ppt and 10 ppb led to significant uptake by the plants. The uptake was proportional to HONO concentrations and linearly related to stomatal conductivity. HONO losses at the cuticle were of minor importance. Our data imply a quick metabolism of HONO and it is concluded that the uptake of HONO by plants is only limited by diffusion of HONO through the plants stomata. Comparing results from measurements with and without plants in the chamber it is furthermore concluded that a compensation point for HONO uptake is below 20 ppt if it exists at all. Heterogeneous formation of HONO by reactions of NO 2 on the plant surfaces was either not effective or compensated by the stomatal uptake of HONO. The data of the present study imply that plant surfaces represent a sink for HONO. Therefore, it was concluded that processes on plant surfaces cannot explain HONO formation on ground surfaces as observed in field studies.

  12. Simultaneous measurements of atmospheric HONO and NO2 via absorption spectroscopy using tunable mid-infrared continuous-wave quantum cascade lasers

    NASA Astrophysics Data System (ADS)

    Lee, B. H.; Wood, E. C.; Zahniser, M. S.; McManus, J. B.; Nelson, D. D.; Herndon, S. C.; Santoni, G. W.; Wofsy, S. C.; Munger, J. W.

    2011-02-01

    Nitrous acid (HONO) is important as a significant source of hydroxyl radical (OH) in the troposphere and as a potent indoor air pollutant. It is thought to be generated in both environments via heterogeneous reactions involving nitrogen dioxide (NO2). In order to enable fast-response HONO detection suitable for eddy-covariance flux measurements and to provide a direct method that avoids interferences associated with derivatization, we have developed a 2-channel tunable infrared laser differential absorption spectrometer (TILDAS) capable of simultaneous high-frequency measurements of HONO and NO2. Beams from two mid-infrared continuous-wave mode quantum cascade lasers (cw-QCLs) traverse separate 210 m paths through a multi-pass astigmatic sampling cell at reduced pressure for the direct detection of HONO (1660 cm-1) and NO2 (1604 cm-1). The resulting one-second detection limits (S/N=3) are 300 and 30 ppt (pmol/mol) for HONO and NO2, respectively. Our HONO quantification is based on revised line-strengths and peak positions for cis-HONO in the 6-micron spectral region that were derived from laboratory measurements. An essential component of ambient HONO measurements is the inlet system and we demonstrate that heated surfaces and reduced pressure minimize sampling artifacts.

  13. Development and deployment of a cavity enhanced UV-LED spectrometer for measurements of atmospheric HONO and NO2 in Hong Kong

    NASA Astrophysics Data System (ADS)

    Wu, Tao; Zha, Qiaozhi; Chen, Weidong; Xu, Zheng; Wang, Tao; He, Xingdao

    2014-10-01

    An optical analytical instrument based on light emitting diode (LED) incoherent broadband cavity enhanced absorption spectroscopy (LED-IBBCEAS) was developed for simultaneous measurements of HONO and NO2 in ambient air. Detection limits (for signal-to-noise ratio, SNR = 2) of 0.6 ppbv for HONO and 2 ppbv for NO2 were achieved with an optimum acquisition time of 120 s. Field intercomparison campaign at a suburban site of Tung Chung in Hong Kong was carried out. Daytime and nighttime concentrations of HONO and NO2 were recorded and compared with data from a long path absorption photometer (LOPAP) and a NOx analyzer equipped with a blue light converter. The test of such a LED-IBBCEAS setup by the measurement intercomparison with the well established HONO and NO2 measurement instruments, for the first time, in a real atmospheric environment, demonstrated the feasibility of the proposed technique for the measurement of environmental HONO and NO2 concentrations in a manner that is free of chemical and spectral interference. During the measurement period from 12:32 on May 12th to 12:32 on May 14th, 2012, the quantitative assessments from these techniques showed well agreed data. High temporal correlations of HONO with NOx and CO were observed, and possible formation sources of HONO are discussed. Occasional inconsistencies in the quantitative assessment of HONO were observed during the in-field campaign. The problems encountered by the IBBCEAS technique applied to field observation and the further improvements are discussed.

  14. HONO and Inorganic Fine Particle Composition in Typical Monsoon Region with Intensive Anthropogenic Emission: In-situ Observations and Source Identification.

    NASA Astrophysics Data System (ADS)

    Xie, Y.; Nie, W.; Ding, A.; Huang, X.

    2015-12-01

    Yangtze River Delta (YRD) is one of the most typical monsoon area with probably the most largest population intensity in the world. With sharply economic development and the large anthropogenic emissions, fine particle pollution have been one of the major air quality problem and may further have impact on the climate system. Though a lot of control policy (sulfur emission have been decreasing from 2007) have been conducted in the region, studies showed the sulfate in fine particles still take major fraction as the nitrate from nitrogen oxides increased significantly. In this study, the role of inorganic chemical compositions in fine particles was investigated with two years in-situ observation. Sulfate and Nitrate contribute to fine particle mass equally in general, but sulfate contributes more during summer and nitrate played more important role in winter. Using lagrangian dispersion backward modeling and source contribution clustering method, the impact of airmass coming from different source region (industrial, dust, biogenic emissions, etc) on fine particle inorganic compositions were discussed. Furthermore, we found two unique cases showing in-situ implications for sulfate formation by nitrogen dioxide oxidation mechanisms. It was showed that the mixing of anthropogenic pollutants with long-range transported mineral dust and biomass burning plume would enhance the sulfate formation by different chemistry mechanisms. This study focus on the complex aspects of fine particle formation in airmasses from different source regions: . It highlights the effect of NOx in enhancing the atmospheric oxidization capacity and indicates a potentially very important impact of increasing NOx on air pollution formation and regional climate change in East Asia.

  15. Four years of ground-based MAX-DOAS observations of HONO and NO2 in the Beijing area

    NASA Astrophysics Data System (ADS)

    Hendrick, F.; Müller, J.-F.; Clémer, K.; Wang, P.; De Mazière, M.; Fayt, C.; Gielen, C.; Hermans, C.; Ma, J. Z.; Pinardi, G.; Stavrakou, T.; Vlemmix, T.; Van Roozendael, M.

    2014-01-01

    corresponding cycles of the HONO total VCD and are therefore likely driven mainly by the balance between HONO sources and the photolytic sink, whereas dilution effects appear to play only a minor role. The estimation of OH radical production from HONO and O3 photolysis based on retrieved HONO near-surface concentrations and calculated photolysis rates indicate that in the 0-200 m altitude range, HONO is by far the largest source of OH radicals in winter as well as in the early morning at all seasons, while the contribution of O3 dominates in summer from mid-morning until mid-afternoon.

  16. Direct measurements of HONO and NO2 by tunable infrared differential absorption spectroscopy; Results from two field campaigns sampling aircraft exhaust and ambient urban air

    NASA Astrophysics Data System (ADS)

    Lee, B. H.; Santoni, G.; Herndon, S. C.; Wood, E. C.; Miake-Lye, R. C.; Munger, J. W.; Wofsy, S. C.; Zahniser, M. S.; McManus, J. B.; Nelson, D. D.

    2009-12-01

    Nitrous acid (HONO) is an important source of hydroxyl radicals (OH), the main oxidizing agent in the atmosphere. However, gaseous HONO has historically proven difficult to measure accurately and to date there is no standard technique. We describe a new instrument capable of high-frequency measurements of HONO and nitrogen dioxide (NO2) mixing ratios by tunable infrared differential absorption spectrometry. Mid-infrared light from two continuous-wave mode quantum cascade lasers traverse a 210 m path through a multi-pass astigmatic cell at reduced pressures for the direct detection of HONO (1660 cm-1) and NO2 (1604 cm-1). We achieve an absorbance precision less than 3×10-6 Hz-1 in one second, which translates to detection limits (S/N=3) of 300 and 30 ppt for HONO and NO2, respectively, in one second. Both lasers and the detector are thermoelectrically cooled, facilitating long-term unattended measurements. We also report preliminary results from two field campaigns; the Alternative Aviation Fuels Experiment (AAFEX) and the Study of Houston Air Radical Precursors (SHARP). At AAFEX, HONO emission ratios relative to CO2 and NOy observed in commercial aircraft exhaust are larger than in most other combustion sources and likely to play a significant role in regional HOx chemistry. Preliminary analysis from the SHARP campaign shows good agreement in HONO and NO2 levels between various measurement techniques.

  17. Development of an activated carbon filter to remove NO2 and HONO in indoor air.

    PubMed

    Yoo, Jun Young; Park, Chan Jung; Kim, Ki Yeong; Son, Youn-Suk; Kang, Choong-Min; Wolfson, Jack M; Jung, In-Ha; Lee, Sung-Joo; Koutrakis, Petros

    2015-05-30

    To obtain the optimum removal efficiency of NO2 and HONO by coated activated carbon (ACs), the influencing factors, including the loading rate, metal and non-metal precursors, and mixture ratios, were investigated. The NOx removal efficiency (RE) for K, with the same loading (1.0 wt.%), was generally higher than for those loaded with Cu or Mn. The RE of NO2 was also higher when KOH was used as the K precursor, compared to other K precursors (KI, KNO3, and KMnO4). In addition, the REs by the ACs loaded with K were approximately 38-55% higher than those by uncoated ACs. Overall, the REs (above 95%) of HONO and NOx with 3% KOH were the highest of the coated AC filters that were tested. Additionally, the REs of NOx and HONO using a mixing ratio of 6 (2.5% PABA (p-aminobenzoic acid)+6% H3PO4):4 (3% KOH) were the highest of all the coatings tested (both metal and non-metal). The results of this study show that AC loaded with various coatings has the potential to effectively reduce NO2 and HONO levels in indoor air.

  18. Tropospheric HONO and reactions of oxides of nitrogen with NaCl

    NASA Astrophysics Data System (ADS)

    Vogt, Rainer; Finlayson-Pitts, Barbara J.

    1994-10-01

    Although nitrous acid is important in both the polluted and remote troposphere, as well as indoors, its mechanisms of production from oxides of nitrogen are not well known. The reactions of N2O5 with NaCl and NaBr in sea salt particles in the presence of water have been hypothesized recently to act as sources of particulate nitrite and which forms gaseous HONO. We report here the results of studies of the reactions of N2O5, HONO and NO2 with NaCl using diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) to follow the formation of products on the salt surface. The infrared band arising from species formed on the salt surface can be attributed to nitrate ions associated with water molecules; the presence of NO(-) was confirmed by chemical analysis of the reacted salts. No nitrite was detected either by DRIFTS or by chemical analysis. Thus the reactions of sea salt particles with N2O5 in the troposphere are not expected to be significant sources of particle nitrite nor of gaseous HONO via conversion of the particle nitrite.

  19. Intercomparison of field measurements of nitrous acid (HONO) during the SHARP campaign

    NASA Astrophysics Data System (ADS)

    Pinto, J. P.; Dibb, J.; Lee, B. H.; Rappenglück, B.; Wood, E. C.; Levy, M.; Zhang, R.-Y.; Lefer, B.; Ren, X.-R.; Stutz, J.; Tsai, C.; Ackermann, L.; Golovko, J.; Herndon, S. C.; Oakes, M.; Meng, Q.-Y.; Munger, J. W.; Zahniser, M.; Zheng, J.

    2014-05-01

    Because of the importance of HONO as a radical reservoir, consistent and accurate measurements of its concentration are needed. As part of SHARP (Study of Houston Atmospheric Radical Precursors), time series of HONO were obtained by six different measurement techniques on the roof of the Moody Tower at the University of Houston. Techniques used were long path differential optical absorption spectroscopy (DOAS), stripping coil-visible absorption photometry (SC-AP), long path absorption photometry (LOPAP®), mist chamber/ion chromatography (MC-IC), quantum cascade-tunable infrared laser differential absorption spectroscopy (QC-TILDAS), and ion drift-chemical ionization mass spectrometry (ID-CIMS). Various combinations of techniques were in operation from 15 April through 31 May 2009. All instruments recorded a similar diurnal pattern of HONO concentrations with higher median and mean values during the night than during the day. Highest values were observed in the final 2 weeks of the campaign. Inlets for the MC-IC, SC-AP, and QC-TILDAS were collocated and agreed most closely with each other based on several measures. Largest differences between pairs of measurements were evident during the day for concentrations < ~100 parts per trillion (ppt). Above ~ 200 ppt, concentrations from the SC-AP, MC-IC, and QC-TILDAS converged to within about 20%, with slightly larger discrepancies when DOAS was considered. During the first 2 weeks, HONO measured by ID-CIMS agreed with these techniques, but ID-CIMS reported higher values during the afternoon and evening of the final 4 weeks, possibly from interference from unknown sources. A number of factors, including building related sources, likely affected measured concentrations.

  20. Nitrogen Oxides in the Nocturnal Boundary Layer: Chemistry of Nitrous Acid (HONO) and the Nitrate Radical (N03)

    SciTech Connect

    Jochen Stutz

    2005-05-24

    dependent. Measurements at one altitude, for example at the ground, where most air quality monitoring stations are located, are not representative for the rest of the NBL. Our model also revealed that radical chemistry is, in general, altitude dependent at night. We distinguish three regions: an unreactive, NO rich, ground layer; an upper, O3 and NO3 dominated layer, and a reactive mixing layer, where RO2 radicals are mixed from aloft with NO from the ground. In this reactive layer an active radical chemistry and elevated OH radical levels can be found. The downward transport of N2O5 and HO2NO2, followed by their thermal decay, was also identified as a radical source in this layer. Our observations also gave insight into the formation of HONO in the NBL. Based on our field experiments we were able to show that the NO2 to HONO conversion was relative humidity dependent. While this fact was well known, we found that it is most likely the uptake of HONO onto surfaces which is R.H. dependent, rather than the NO2 to HONO conversion. This finding led to the proposal of a new NO2 to HONO conversion mechanism, which is based on solid physical chemical principles. Noteworthy is also the observation of enhanced NO2 to HONO conversion during a dust storm event in Phoenix. The final activity in our project investigated the influence of the urban canopy, i.e. building walls and surfaces, on nocturnal chemistry. For the first time the surface area of a city was determined based on a Geographical Information System database of the city of Santa Monica. The surface to volume areas found in this study showed that, in the 2 lower part of the NBL, buildings provide a much larger surface area than the aerosol. In addition, buildings take up a considerable amount of the volume near the ground. The expansion of our model and sensitivity studies based on the Santa Monica data revealed that the surface area of buildings considerably influences HONO levels in urban areas. The volume reduction leads

  1. 17 CFR 37.408 - Additional sources for compliance.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 17 Commodity and Securities Exchanges 1 2014-04-01 2014-04-01 false Additional sources for compliance. 37.408 Section 37.408 Commodity and Securities Exchanges COMMODITY FUTURES TRADING COMMISSION SWAP EXECUTION FACILITIES Monitoring of Trading and Trade Processing § 37.408 Additional sources...

  2. 17 CFR 38.201 - Additional sources for compliance.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 17 Commodity and Securities Exchanges 1 2013-04-01 2013-04-01 false Additional sources for compliance. 38.201 Section 38.201 Commodity and Securities Exchanges COMMODITY FUTURES TRADING COMMISSION DESIGNATED CONTRACT MARKETS Contracts Not Readily Subject to Manipulation § 38.201 Additional sources...

  3. 17 CFR 38.201 - Additional sources for compliance.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 17 Commodity and Securities Exchanges 1 2014-04-01 2014-04-01 false Additional sources for compliance. 38.201 Section 38.201 Commodity and Securities Exchanges COMMODITY FUTURES TRADING COMMISSION DESIGNATED CONTRACT MARKETS Contracts Not Readily Subject to Manipulation § 38.201 Additional sources...

  4. The dark decay of hono in environmental (SMOG) chambers

    NASA Astrophysics Data System (ADS)

    Ten Brink, Harry M.; Spoelstra, Henk

    The dark decay of nitrous acid gas (HONO), added to filtered outside air in a glass/pyrex smog chamber, was studied. For the concentrations used in the study, in the range of 1-10 ppmv, a decay with a half-life value of hours was found. Since the decay rate increased with HONG concentration and was quite reproducible, it was analyzed as a second-order reaction and a rate constant of (1.5 ± 0.3) 10 -19 cm 3 molec -1 s -1 was obtained. This is very similar to a value obtained in a previous study in a chamber with similar wall material. High concentrations of copper oxide aerosols and NaCl droplets did not measurably accelerate the decay. There was some removal of HONO by reaction with NaCl, as evidenced by the formation of aerosol-nitrate, but the contribution of this process to the total loss of HONO was negligible. Whereas initially only a limited amount of NO was formed as a result of the decay of HONO, the subsequent loss of HONG was via decomposition into NO and NO 2 (and H 2O). The final concentrations of the gases were in accordance with the equilibrium values calculated with the equilibrium constant from an earlier study. The decay was also studied at relative humidities approaching saturation. It was found that the decay varied from experiment to experiment but that it was on average a factor of ten faster than at the standard relative humidity of 80%. The acceleration is ascribed to catalysis of the decay adsorbed water at the walls of the chamber.

  5. Volume 3a - Area Source Methods - Additional Documents

    EPA Pesticide Factsheets

    Nonpoint (area) source emission reference materials from the Emissions Inventory Improvement Program (EIIP). Provides nonpoint source guidance on ammonia emissions from natural landscapes, fertilized soils, and nonagricultural sources.

  6. Intercomparison of field measurements of nitrous acid (HONO) during the SHARP Campaign

    EPA Science Inventory

    Because of the importance of HONO as a radical reservoir, consistent and accurate measurements of its concentration are needed. As part of the SHARP (Study of Houston Atmospheric Radical Precursors), time series of HONO were obtained by five different measurement techniques on th...

  7. Biological soil crusts emit large amounts of NO and HONO affecting the nitrogen cycle in drylands

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

    Dryland systems currently cover ˜40% of the world's land surface and are still expanding as a consequence of human impact and global change. In contrast to that, information on their role in global biochemical processes is limited, probably induced by the presumption that their sparse vegetation cover plays a negligible role in global balances. However, spaces between the sparse shrubs are not bare, but soils are mostly covered by biological soil crusts (biocrusts). These biocrust communities belong to the oldest life forms, resulting from an assembly between soil particles and cyanobacteria, lichens, bryophytes, and algae plus heterotrophic organisms in varying proportions. Depending on the dominating organism group, cyanobacteria-, lichen-, and bryophyte-dominated biocrusts are distinguished. Besides their ability to restrict soil erosion they fix atmospheric carbon and nitrogen, and by doing this they serve as a nutrient source in strongly depleted dryland ecosystems. In this study we show that a fraction of the nitrogen fixed by biocrusts is metabolized and subsequently returned to the atmosphere in the form of nitric oxide (NO) and nitrous acid (HONO). These gases affect the radical formation and oxidizing capacity within the troposphere, thus being of particular interest to atmospheric chemistry. Laboratory measurements using dynamic chamber systems showed that dark cyanobacteria-dominated crusts emitted the largest amounts of NO and HONO, being ˜20 times higher than trace gas fluxes of nearby bare soil. We showed that these nitrogen emissions have a biogenic origin, as emissions of formerly strongly emitting samples almost completely ceased after sterilization. By combining laboratory, field, and satellite measurement data we made a best estimate of global annual emissions amounting to ˜1.1 Tg of NO-N and ˜0.6 Tg of HONO-N from biocrusts. This sum of 1.7 Tg of reactive nitrogen emissions equals ˜20% of the soil release under natural vegetation according

  8. Heterogeneous interaction and reaction of HONO on ice films between 173 and 230 K

    SciTech Connect

    Chu, L.; Diao, G.; Chu, L.T.

    2000-04-13

    Both the heterogeneous interaction of HONO on the ice surface and the heterogeneous reaction of HONO with HBr on the ice surface have been investigated in a flow reactor interfaced with a differentially pumped quadrupole mass spectrometer. The surface uptake amount and initial uptake coefficient of HONO on the ice surface were determined as a function of the ice-film temperature between 173 and 205 K. The reaction probability of HONO over the HBr-treated ice surfaces has been determined as a function of HBr partial pressures at 190K, 200K, and 230K, respectively. The reaction mechanism is proposed and discussed. Kinetic analysis indicates that the heterogeneous reaction of HONO with HBr on ice surfaces follows the Eley-Rideal type.

  9. Ab initio study of the H + HONO reaction: Direct abstraction versus indirect exchange processes

    SciTech Connect

    Hsu, C.C.; Lin, M.C.; Mebel, A.M.; Melius, C.F.

    1997-01-02

    The mechanism of the H + HONO reaction (for which no experimental data are available) has been elucidated by ab initio molecular orbital calculations using modified G2 and BAC-MP4 methods. These results indicate that the reaction occurs predominantly by two indirect metathetical processes. One produces OH + HNO and H{sub 2}O + NO from the decomposition of vibrationally excited hydroxyl nitroxide, HN(O)OH, formed by H atom addition to the N atom of HONO. The other produces H{sub 2}O + NO from the decomposition of vibrationally excited dihydroxylamino radical, N(OH){sub 2}, formed by H atom addition to the terminal O atom. These indirect displacement processes are much more efficient than the commonly assumed, direct H-abstraction reaction producing H{sub 2} + NO{sub 2}. A transition-state theory calculation for the direct abstraction reaction and RRKM calculations for the two indirect displacement processes give rise to the following rate constants, in units of cm{sup 3} molecule{sup -1} s{sup -1} for the 300-3500 K temperature range under atmospheric conditions: k{sub H(2)} = 3.33 x 10{sup -16}T{sup 1.55} exp(-3328.5/T), k{sub OH} = 9.36 x 10{sup -14}T{sup 0.86} exp(-2500.8/T), k{sub H(2)O} = 1.35 x 10{sup -17}T{sup 1.89} exp-(-1935.7/T), where the rate constant for H{sub 2}O production represents the sum from both indirect displacement reactions. 32 refs., 3 figs., 7 tabs.

  10. Percolation model with an additional source of disorder

    NASA Astrophysics Data System (ADS)

    Kundu, Sumanta; Manna, S. S.

    2016-06-01

    The ranges of transmission of the mobiles in a mobile ad hoc network are not uniform in reality. They are affected by the temperature fluctuation in air, obstruction due to the solid objects, even the humidity difference in the environment, etc. How the varying range of transmission of the individual active elements affects the global connectivity in the network may be an important practical question to ask. Here a model of percolation phenomena, with an additional source of disorder, is introduced for a theoretical understanding of this problem. As in ordinary percolation, sites of a square lattice are occupied randomly with probability p . Each occupied site is then assigned a circular disk of random value R for its radius. A bond is defined to be occupied if and only if the radii R1 and R2 of the disks centered at the ends satisfy a certain predefined condition. In a very general formulation, one divides the R1-R2 plane into two regions by an arbitrary closed curve. One defines a point within one region as representing an occupied bond; otherwise it is a vacant bond. The study of three different rules under this general formulation indicates that the percolation threshold always varies continuously. This threshold has two limiting values, one is pc(sq) , the percolation threshold for the ordinary site percolation on the square lattice, and the other is unity. The approach of the percolation threshold to its limiting values are characterized by two exponents. In a special case, all lattice sites are occupied by disks of random radii R ∈{0 ,R0} and a percolation transition is observed with R0 as the control variable, similar to the site occupation probability.

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

    PubMed Central

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

    2015-01-01

    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. PMID:26621714

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

    PubMed

    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.

  13. Radiation safety attached to radioactive sources management - additional aspects

    SciTech Connect

    Kositsyn, V.F.

    1993-12-31

    Radiation sources are used in many scientific areas. Safety management requirements are determined for them with guarantee of the international and national dose limits unexceeding. As a rule, such dose limits are being developed concerning the type, energy, and flux of main radiation. Lack of knowledge of these attendant radiations can put personnel in danger. The study of the attendant neutron and gamma-radiations for plutonium 128 alpha sources was made.

  14. Measurements of HONO, NO, NOy and SO2 in aircraft exhaust plumes at cruise

    NASA Astrophysics Data System (ADS)

    Jurkat, T.; Voigt, C.; Arnold, F.; Schlager, H.; Kleffmann, J.; Aufmhoff, H.; Schäuble, D.; Schaefer, M.; Schumann, U.

    2011-05-01

    Measurements of gaseous nitrogen and sulfur oxide emissions in young aircraft exhaust plumes give insight into chemical oxidation processes inside aircraft engines. Particularly, the OH-induced formation of nitrous acid (HONO) from nitrogen oxide (NO) and sulfuric acid (H2SO4) from sulfur dioxide (SO2) inside the turbine which is highly uncertain, need detailed analysis to address the climate impact of aviation. We report on airborne in situ measurements at cruise altitudes of HONO, NO, NOy, and SO2 in 9 wakes of 8 different types of modern jet airliners, including for the first time also an A380. Measurements of HONO and SO2 were made with an ITCIMS (Ion Trap Chemical Ionization Mass Spectrometer) using a new ion-reaction scheme involving SF5- reagent ions. The measured molar ratios HONO/NO and HONO/NOy with averages of 0.038 ± 0.010 and 0.027 ± 0.005 were found to decrease systematically with increasing NOx emission-index (EI NOx). We calculate an average EI HONO of 0.31 ± 0.12 g NO2 kg-1. Using reliable measurements of HONO and NOy, which are less adhesive than H2SO4 to the inlet walls, we derive the OH-induced conversion fraction of fuel sulfur to sulfuric acid $\\varepsilon$ with an average of 2.2 ± 0.5 %. $\\varepsilon$ also tends to decrease with increasing EI NOx, consistent with earlier model simulations. The lowest HONO/NO, HONO/NOy and $\\varepsilon$ was observed for the largest passenger aircraft A380.

  15. ENERGETIC NEUTRAL ATOMS: AN ADDITIONAL SOURCE FOR HELIOSPHERIC PICKUP IONS

    SciTech Connect

    Bochsler, Peter; Moebius, Eberhard

    2010-09-20

    Recently, Schwadron and McComas discussed the possibility of inner source pickup particles originating from the ionization of energetic neutral atoms (ENAs), based on new data from the IBEX mission. This proposition has some interesting features, namely, it might be able to explain why inner source pickup ions (PUIs) have a composition resembling solar abundances and show no indication of overabundance of refractory elements, although this should be expected, if the conventional explanation of solar wind-dust interaction for the origin of this heliospheric component were correct. In this Letter, we explore further consequences for ENA-related PUIs and investigate their velocity distributions. We conclude that this model will not reproduce the observed velocity distributions of inner source PUIs and point out a substantial deviation in their composition. However, it seems likely that the ionization of ENAs as observed with IBEX could contribute a significant amount of heliospheric suprathermal tail ions. Some possible consequences of our investigation for heliospheric particle populations are briefly discussed.

  16. Additional muon calculations for the SLC positron source

    SciTech Connect

    Nelson, W.R.; McCall, R.C.

    1985-04-23

    This note is an update to the muon calculations presented in CN-221 and takes into account: (1) a more complete muon production and transport model, including an estimate of wide angle production based on experimental data, (2) additional earth shielding that will be added on top and both sides of the 2/3 tunnel areas, and (3) a detailed analysis of the earth profile as it pertains to shielding in the direction of the SLAC site boundary. The highest annual dose at the SLAC boundary is found to be 13 mrem/year (4000 hours of operation at 50 kW), and this occurs at a horizontal angle of 0 degrees and a vertical angle of 3.6 degrees relative to the incident beam direction. Although the shielding criteria is 10 mrem/year at the site boundary, the radiation transport model becomes somewhat conservative at large distances from the shield, which should bring the 13 mrem/year number actually well below the criteria. This point is also about 28 feet above the roadway. Extension of this line may strike the ground in the Christmas tree farm beyond the SLAC boundary but there will be additional attenuation due to distance. We do not recommend that any additional shielding be added at this time. 4 refs., 1 fig.

  17. Light-induced nitrous acid (HONO) production from NO2 heterogeneous reactions on household chemicals

    NASA Astrophysics Data System (ADS)

    Gómez Alvarez, Elena; Sörgel, Matthias; Gligorovski, Sasho; Bassil, Sabina; Bartolomei, Vincent; Coulomb, Bruno; Zetzsch, Cornelius; Wortham, Henri

    2014-10-01

    Nitrous acid (HONO) can be generated in various indoor environments directly during combustion processes or indirectly via heterogeneous NO2 reactions with water adsorbed layers on diverse surfaces. Indoors not only the concentrations of NO2 are higher but the surface to volume (S/V) ratios are larger and therefore the potential of HONO production is significantly elevated compared to outdoors. It has been claimed that the UV solar light is largely attenuated indoors. Here, we show that solar light (λ > 340 nm) penetrates indoors and can influence the heterogeneous reactions of gas-phase NO2 with various household surfaces. The NO2 to HONO conversion mediated by light on surfaces covered with domestic chemicals has been determined at atmospherically relevant conditions i.e. 50 ppb NO2 and 50% RH. The formation rates of HONO were enhanced in presence of light for all the studied surfaces and are determined in the following order: 1.3·109 molecules cm-2 s-1 for borosilicate glass, 1.7·109 molecules cm-2 s-1 for bathroom cleaner, 1.0·1010 molecules cm-2 s-1 on alkaline detergent (floor cleaner), 1.3·1010 molecules cm-2 s-1 for white wall paint and 2.7·1010 molecules cm-2 s-1 for lacquer. These results highlight the potential of household chemicals, used for cleaning purposes to generate HONO indoors through light-enhanced NO2 heterogeneous reactions. The results obtained have been applied to predict the timely evolution of HONO in a real indoor environment using a dynamic mass balance model. A steady state mixing ratio of HONO has been estimated at 1.6 ppb assuming a contribution from glass, paint and lacquer and considering the photolysis of HONO as the most important loss process.

  18. Consistency of the Health of the Nation Outcome Scales (HoNOS) at inpatient-to-community transition

    PubMed Central

    Harvey, Richard; Phung, Dinh; Venkatesh, Svetha; Connor, Jason P

    2016-01-01

    Objectives The Health of the Nation Outcome Scales (HoNOS) are mandated outcome-measures in many mental-health jurisdictions. When HoNOS are used in different care settings, it is important to assess if setting specific bias exists. This article examines the consistency of HoNOS in a sample of psychiatric patients transitioned from acute inpatient care and community centres. Setting A regional mental health service with both acute and community facilities. Participants 111 psychiatric patients were transferred from inpatient care to community care from 2012 to 2014. Their HoNOS scores were extracted from a clinical database; Each inpatient-discharge assessment was followed by a community-intake assessment, with the median period between assessments being 4 days (range 0–14). Assessor experience and professional background were recorded. Primary and secondary outcome measures The difference of HoNOS at inpatient-discharge and community-intake were assessed with Pearson correlation, Cohen's κ and effect size. Results Inpatient-discharge HoNOS was on average lower than community-intake HoNOS. The average HoNOS was 8.05 at discharge (median 7, range 1–22), and 12.16 at intake (median 12, range 1–25), an average increase of 4.11 (SD 6.97). Pearson correlation between two total scores was 0.073 (95% CI −0.095 to 0.238) and Cohen's κ was 0.02 (95% CI −0.02 to 0.06). Differences did not appear to depend on assessor experience or professional background. Conclusions Systematic change in the HoNOS occurs at inpatient-to-community transition. Some caution should be exercised in making direct comparisons between inpatient HoNOS and community HoNOS scores. PMID:27121703

  19. Additives

    NASA Technical Reports Server (NTRS)

    Smalheer, C. V.

    1973-01-01

    The chemistry of lubricant additives is discussed to show what the additives are chemically and what functions they perform in the lubrication of various kinds of equipment. Current theories regarding the mode of action of lubricant additives are presented. The additive groups discussed include the following: (1) detergents and dispersants, (2) corrosion inhibitors, (3) antioxidants, (4) viscosity index improvers, (5) pour point depressants, and (6) antifouling agents.

  20. Known Unknowns Explained: Hono Daytime Production from the Anion-Catalyzed Uptake of NO2 on Secondary Organic Aerosol

    NASA Astrophysics Data System (ADS)

    Colussi, A. J.

    2012-12-01

    Recent evidence strongly suggests that the decay of NO2 in urban air and the related production of HONO at daytime involve unidentified multiphase reactions. Here we address these issues and analyze the results of field campaigns from the perspective of our laboratory studies on interfacial NO2 chemistry. We note that the similar (~ 4 hr) NO2 decay lifetimes inferred from satellite sightings over megacities ranging from 2° N to 40° N at all seasons are incompatible with the conventional view that NO2 is removed (as HNO3) by gas-phase OH-radicals whose concentrations depend on solar irradiance. This insight also applies to the daytime source of HONO, a non-photochemical process that reaches its maximal strength at noon. Herein, we present new laboratory experiments and quantum mechanical calculations confirming that the reactive uptake of gaseous NO2 on aqueous interfaces is generally catalyzed by anions, and show that the preceding observations can be accounted for by the disproportionation of NO2 (via 2 NO2 + H2O = H+ + NO3- + HONO) on secondary organic aerosol particles containing carboxylate ion loadings that peak at noon, as reported elsewhere.IGURE 1 - Left axis: The frequencies of O(1D) atom production from the solar photolysis of ozone, J(O1D), at zero elevation under an ozone column of 300 Dobson units at noon on (from left to right) Feb. 1st, May 1st, Aug. 1st and Nov. 1st over: (1) Singapore 1.3° N, (2) Pearl River Delta 22.5° N, (3) Riyadh 24.6° N, (4) Isfahan 32.6° N, (5) Los Angeles 34° N, (6) Tokyo 35.6° N, (7) Four Corners 36.7° N, (8) Madrid 40.4° N and (9) Moscow 55.8° N. Right axis (note the logarithmic scale): red dashes correspond to the ratios J(O1D)mid-summer/J(O1D)mid-winter (herein midsummer is Aug. 1st, midwinter is Feb. 1st).

  1. Potential role of the nitroacidium ion on HONO emissions from the snowpack.

    PubMed

    Hellebust, Stig; Roddis, Tristan; Sodeau, John R

    2007-02-22

    The effects of photolysis on frozen, thin films of water-ice containing nitrogen dioxide (as its dimer dinitrogen tetroxide) have been investigated using a combination of Fourier transform reflection-absorption infrared (FT-RAIR) spectroscopy and mass spectrometry. The release of HONO is ascribed to a mechanism in which nitrosonium nitrate (NO+NO3-) is formed. Subsequent solvation of the cation leads to the nitroacidium ion, H2ONO+, i.e., protonated nitrous acid. The pathway proposed explains why the field measurement of HONO at different polar sites is often contradictory.

  2. Development of a Thermal Dissociation Chemiluminescence Instrument for In Situ Detection of HONO

    NASA Astrophysics Data System (ADS)

    Perez, I. M.; Wooldridge, P. J.; Cohen, R. C.

    2005-12-01

    We describe a new method for in situ detection of nitrous acid (HONO) using a combination of thermal dissociation (TD) and chemiluminescent (CL) detection of nitric oxide. A prototype was developed using a commercial NO sensor to evaluate the method. Laboratory tests for possible chemical interferences show that NO2, peroxy nitrates, alkyl nitrates, HNO3, O3 and H2O affect the measurements. A strategy for accounting for these effects is described. Our analyses show that HONO concentration observed using TD-CL will be accurate to ± 20% and that under typical urban conditions the method will have a detection limit of 5ppt.

  3. Heterogeneous Chemistry of HONO on Liquid Sulfuric Acid: A New Mechanism of Chlorine Activation on Stratospheric Sulfate Aerosols

    NASA Technical Reports Server (NTRS)

    Zhang, Renyi; Leu, Ming-Taun; Keyser, Leon F.

    1996-01-01

    Heterogeneous chemistry of nitrous acid (HONO) on liquid sulfuric acid (H2SO4) Was investigated at conditions that prevail in the stratosphere. The measured uptake coefficient (gamma) of HONO on H2SO4 increased with increasing acid content, ranging from 0.03 for 65 wt % to about 0.1 for 74 wt %. In the aqueous phase, HONO underwent irreversible reaction with H2SO4 to form nitrosylsulfuric acid (NO(+)HSO4(-). At temperatures below 230 K, NO(+)HSO4(-) was observed to be stable and accumulated in concentrated solutions (less than 70 wt % H2SO4) but was unstable and quickly regenerated HONO in dilute solutions (less than 70 wt %). HCl reacted with HONO dissolved in sulfuric acid, releasing gaseous nitrosyl chloride (ClNO). The reaction probability between HCl and HONO varied from 0.01 to 0.02 for 60-72 wt % H2SO4. In the stratosphere, ClNO photodissociates rapidly to yield atomic chlorine, which catalytically destroys ozone. Analysis of the laboratory data reveals that the reaction of HCl with HONO on sulfate aerosols can affect stratospheric ozone balance during elevated sulfuric acid loadings after volcanic eruptions or due to emissions from the projected high-speed civil transport (HSCT). The present results may have important implications on the assessment of environmental acceptability of HSCT.

  4. Resolving the HONO formation mechanism in the ionosphere via ab initio molecular dynamic simulations

    PubMed Central

    He, Rongxing; Li, Lei; Zhong, Jie; Zhu, Chongqin; Francisco, Joseph S.; Zeng, Xiao Cheng

    2016-01-01

    Solar emission produces copious nitrosonium ions (NO+) in the D layer of the ionosphere, 60 to 90 km above the Earth’s surface. NO+ is believed to transfer its charge to water clusters in that region, leading to the formation of gaseous nitrous acid (HONO) and protonated water cluster. The dynamics of this reaction at the ionospheric temperature (200–220 K) and the associated mechanistic details are largely unknown. Using ab initio molecular dynamics (AIMD) simulations and transition-state search, key structures of the water hydrates—tetrahydrate NO+(H2O)4 and pentahydrate NO+(H2O)5—are identified and shown to be responsible for HONO formation in the ionosphere. The critical tetrahydrate NO+(H2O)4 exhibits a chain-like structure through which all of the lowest-energy isomers must go. However, most lowest-energy isomers of pentahydrate NO+(H2O)5 can be converted to the HONO-containing product, encountering very low barriers, via a chain-like or a three-armed, star-like structure. Although these structures are not the global minima, at 220 K, most lowest-energy NO+(H2O)4 and NO+(H2O)5 isomers tend to channel through these highly populated isomers toward HONO formation. PMID:27071120

  5. Resolving the HONO formation mechanism in the ionosphere via ab initio molecular dynamic simulations.

    PubMed

    He, Rongxing; Li, Lei; Zhong, Jie; Zhu, Chongqin; Francisco, Joseph S; Zeng, Xiao Cheng

    2016-04-26

    Solar emission produces copious nitrosonium ions (NO(+)) in the D layer of the ionosphere, 60 to 90 km above the Earth's surface. NO(+) is believed to transfer its charge to water clusters in that region, leading to the formation of gaseous nitrous acid (HONO) and protonated water cluster. The dynamics of this reaction at the ionospheric temperature (200-220 K) and the associated mechanistic details are largely unknown. Using ab initio molecular dynamics (AIMD) simulations and transition-state search, key structures of the water hydrates-tetrahydrate NO(+)(H2O)4 and pentahydrate NO(+)(H2O)5-are identified and shown to be responsible for HONO formation in the ionosphere. The critical tetrahydrate NO(+)(H2O)4 exhibits a chain-like structure through which all of the lowest-energy isomers must go. However, most lowest-energy isomers of pentahydrate NO(+)(H2O)5 can be converted to the HONO-containing product, encountering very low barriers, via a chain-like or a three-armed, star-like structure. Although these structures are not the global minima, at 220 K, most lowest-energy NO(+)(H2O)4 and NO(+)(H2O)5 isomers tend to channel through these highly populated isomers toward HONO formation.

  6. Development of a broadband cavity enhanced UV-LED spectrometer for the detection of atmospheric HONO and NO2

    NASA Astrophysics Data System (ADS)

    Wu, Tao; Xia, Ruxiao; Chen, Weidong; He, Xingdao

    2016-10-01

    An incoherent broadband cavity enhanced UV-LED spectrometer (IBBCEAS) was developed to detect atmospheric HONO and NO2. Using a UV light emitting diode (LED) operating at 366 nm in combination with a high finesse optical cavity, HONO and NO2 were able to be simultaneously measured with high sensitivity. Detection limits (for SNR=1) of 0.3 ppbv for HONO and 1 ppbv for NO2 were achieved with an optimum acquisition time of 120 s. Stability of the developed cavity enhanced UV-LED spectrometer has been characterized by means of an Allan variance analysis. Daytime and nighttime concentrations of atmospheric HONO and NO2 were measured and compared with data from LOPAP for HONO and blue light converter-based NOx analyzer for NO2. The present work performed in a real atmospheric environment demonstrates the feasibility of using IBBCEAS technique for interference (chemical and spectral) free measurement of HONO. Experimental detail will be presented, the problems encountered during the real atmospheric measurement will be discussed.

  7. Beamforming for directional sources: additional estimator and evaluation of performance under different acoustic scenarios.

    PubMed

    Bouchard, Christian; Havelock, David I; Bouchard, Martin

    2011-04-01

    Beamforming is done with an array of sensors to achieve a directional or spatially-specific response by using a model of the arriving wavefront. Conventionally, a plane wave or point source model is used and this can cause decreased array gain or even total breakdown of beamforming when the source is directional. To avoid this, the authors proposed in recent work an alternative beamforming method which defines a set of "sub-beamformers," each designed to respond to a different spatial mode of the source. The outputs of the individual sub-beamformers are combined in a weighted sum to give an overall output of better quality than that of a monopole beamformer. This paper extends the previous work by introducing an additional estimator for the weighted sum and by presenting simulation results to demonstrate the relative performance of the proposed method and the different estimators for a directional source in the presence of diffuse noise, reverberation, and an interfering source. Gain optimization subject to a constraint on the white-noise gain with the proposed beamforming method is also introduced. Generally, when beamforming on directional sources, the proposed method outperforms beamforming with a point source model when the input signal-to-noise ratio (SNR) is 0 dB or higher.

  8. Use of additional fission sources or scattering sources to model inward axial leakages in fast-reactor analysis

    SciTech Connect

    Grimm, K.N.; Meneghetti, D.

    1981-10-01

    When calculations of flux are done in less than three dimensions, bucklings are normally used to model leakages (flows) in the dimensions for which the flux is not calculated. If the net leakage for a given energy group is outward (positive), the buckling is positive, and buckling methods work well. However, if the new leakage for a given energy group is inward (negative), the buckling is negative and can lead to numerical instabilities (oscillations in the iterative flux calculation). This report discusses two equivalent nonbuckling methods to model inward leakages. One method (the chi/sub g/ method) models these incoming neutrons by additional fission sources. The other method (the ..sigma../sub s/(1 ..-->.. g) method) models them by increased downscatter sources. The derivation of the two methods is shown, and the flux spectra obtained by their use are compared with those obtained from two-dimensional (RZ) calculations.

  9. Impact of isoprene and HONO chemistry on ozone and OVOC formation in a semirural South Korean forest

    SciTech Connect

    Kim, Saewung; Kim, So-Young; Lee, Meehye; Shim, Heeyoun; Wolfe, Glenn; Guenther, Alex B.; He, Amy; Hong, Youdeog; Han, Jinseok

    2014-01-01

    Rapid urbanization and economic development in East Asia in past decades has led to photochemical air pollution problems such as excess photochemical ozone and aerosol formation. Asian megacities such as Seoul, Tokyo, Shanghai, Gangzhou, and Beijing are surrounded by densely forested areas and recent research has consistently demonstrated the importance of biogenic volatile organic compounds from vegetation in determining oxidation capacity in the suburban Asian megacity regions. Uncertainties in constraining tropospheric oxidation capacity, dominated by hydroxyl radical concentrations, undermine our ability to assess regional photochemical air pollution problems. We present an observational dataset of CO, NOX, SO2, ozone, HONO, and VOCs (anthropogenic and biogenic) from Taehwa Research Forest (TRF) near the Seoul Metropolitan Area (SMA) in early June 2012. The data show that TRF is influenced both by aged pollution and fresh BVOC emissions. With the dataset, we diagnose HOx (OH, HO2, and RO2) distributions calculated with the University of Washington Chemical Box Model (UWCM v 2.1). Uncertainty from unconstrained HONO sources and radical recycling processes highlighted in recent studies is examined using multiple model simulations with different model constraints. The results suggest that 1) different model simulation scenarios cause systematic differences in HOX distributions especially OH levels (up to 2.5 times) and 2) radical destruction (HO2+HO2 or HO2+RO2) could be more efficient than radical recycling (HO2+NO) especially in the afternoon. Implications of the uncertainties in radical chemistry are discussed with respect to ozone-VOC-NOX sensitivity and oxidation product formation rates. Overall, the VOC limited regime in ozone photochemistry is predicted but the degree of sensitivity can significantly vary depending on the model scenarios. The model results also suggest that RO2 levels are positively correlated with OVOCs production that is not routinely

  10. Impact of isoprene and HONO chemistry on ozone and OVOC formation in a semirural South Korean forest

    DOE PAGES

    Kim, S.; Kim, S. -Y.; Lee, M.; ...

    2015-04-29

    Rapid urbanization and economic development in East Asia in past decades has led to photochemical air pollution problems such as excess photochemical ozone and aerosol formation. Asian megacities such as Seoul, Tokyo, Shanghai, Guangzhou, and Beijing are surrounded by densely forested areas, and recent research has consistently demonstrated the importance of biogenic volatile organic compounds (VOCs) from vegetation in determining oxidation capacity in the suburban Asian megacity regions. Uncertainties in constraining tropospheric oxidation capacity, dominated by hydroxyl radical, undermine our ability to assess regional photochemical air pollution problems. We present an observational data set of CO, NOx, SO2, ozone, HONO,more » and VOCs (anthropogenic and biogenic) from Taehwa research forest (TRF) near the Seoul metropolitan area in early June 2012. The data show that TRF is influenced both by aged pollution and fresh biogenic volatile organic compound emissions. With the data set, we diagnose HOx (OH, HO2, and RO2) distributions calculated using the University of Washington chemical box model (UWCM v2.1) with near-explicit VOC oxidation mechanisms from MCM v3.2 (Master Chemical Mechanism). Uncertainty from unconstrained HONO sources and radical recycling processes highlighted in recent studies is examined using multiple model simulations with different model constraints. The results suggest that (1) different model simulation scenarios cause systematic differences in HOx distributions, especially OH levels (up to 2.5 times), and (2) radical destruction (HO2 + HO2 or HO2 + RO2) could be more efficient than radical recycling (RO2 + NO), especially in the afternoon. Implications of the uncertainties in radical chemistry are discussed with respect to ozone–VOC–NOx sensitivity and VOC oxidation product formation rates. Overall, the NOx limited regime is assessed except for the morning hours (8 a.m. to 12 p.m. local standard time), but the degree of sensitivity

  11. Impact of isoprene and HONO chemistry on ozone and OVOC formation in a semirural South Korean forest

    SciTech Connect

    Kim, S.; Kim, S. -Y.; Lee, M.; Shim, H.; Wolfe, G. M.; Guenther, A. B.; He, A.; Hong, Y.; Han, J.

    2015-04-29

    Rapid urbanization and economic development in East Asia in past decades has led to photochemical air pollution problems such as excess photochemical ozone and aerosol formation. Asian megacities such as Seoul, Tokyo, Shanghai, Guangzhou, and Beijing are surrounded by densely forested areas, and recent research has consistently demonstrated the importance of biogenic volatile organic compounds (VOCs) from vegetation in determining oxidation capacity in the suburban Asian megacity regions. Uncertainties in constraining tropospheric oxidation capacity, dominated by hydroxyl radical, undermine our ability to assess regional photochemical air pollution problems. We present an observational data set of CO, NOx, SO2, ozone, HONO, and VOCs (anthropogenic and biogenic) from Taehwa research forest (TRF) near the Seoul metropolitan area in early June 2012. The data show that TRF is influenced both by aged pollution and fresh biogenic volatile organic compound emissions. With the data set, we diagnose HOx (OH, HO2, and RO2) distributions calculated using the University of Washington chemical box model (UWCM v2.1) with near-explicit VOC oxidation mechanisms from MCM v3.2 (Master Chemical Mechanism). Uncertainty from unconstrained HONO sources and radical recycling processes highlighted in recent studies is examined using multiple model simulations with different model constraints. The results suggest that (1) different model simulation scenarios cause systematic differences in HOx distributions, especially OH levels (up to 2.5 times), and (2) radical destruction (HO2 + HO2 or HO2 + RO2) could be more efficient than radical recycling (RO2 + NO), especially in the afternoon. Implications of the uncertainties in radical chemistry are discussed with respect to ozone–VOC–NOx sensitivity and VOC oxidation product

  12. Carbon source utilization profiles suggest additional metabolic interactions in a synergistic linuron-degrading bacterial consortium.

    PubMed

    Horemans, Benjamin; Smolders, Erik; Springael, Dirk

    2013-04-01

    A bacterial triple-species consortium that synergistically metabolizes the phenylurea herbicide linuron was studied to determine whether synergy is extended toward the metabolism of other C-sources. The metabolic performance and range of the individual consortium members were compared with those of paired and three-species combinations in Biolog GN2 MicroPlate assays. The strain combinations showed an increase in the rate and extent of utilization of 80% of the C-sources that were utilized by either one or more of the individual consortium members and the additional utilization of eight C-sources for which oxidation was not observed for the individual strains. When one of the three strains was replaced by bacterial strains 'foreign' to the consortium, either belonging to the same genus or to other genera, mainly antagonistic effects occurred. The data suggest that the consortium members cooperate in the metabolism of C-sources in addition to linuron. This feature can contribute in consolidating consortium composition when linuron is absent or present at low concentrations.

  13. Fast in-situ measurements of glyoxal (CHOCHO) and nitrous acid (HONO) in northern Chinese plane during CAREBEIJING - NCP2014

    NASA Astrophysics Data System (ADS)

    Min, K. E.; Dube, W. P.; Washenfelder, R. A.; Langford, A. O.; Brown, S. S.; Broch, S.; Fuchs, H.; Gomm, S.; Hofzumahaus, A.; Holland, F.; Hu, M.; Huey, L. G.; Kubik, K.; Li, X.; Liu, X.; Lu, K.; Rohrer, F.; Shao, M.; Sjostedt, S. J.; Tan, Z.; Zhu, T.; Wahner, A.; Wang, B.; Wang, M.; Wang, Y.; Zeng, L.; Zhang, Y.

    2014-12-01

    The Northern China Plain has experienced visibility degradation and detrimental health impacts due to aerosol and photochemical pollution. To examine these air quality issues, CAREBEIJING-NCP2014 (Care Beijing - Northern China Plain 2014) was held in WangDu, Hebei province, China from 6 June to 15 July 2014. We deployed our newly developed instrument, ACES (Airborne Cavity Enhanced Spectrometer), for high time resolution in-situ measurement of glyoxal (CHOCHO), nitrous acid (HONO) and other trace gases (NO2, H2O) to investigate mechanisms of oxidation processes and secondary organic aerosol (SOA) formation. The in situ measurements of CHOCHO provide observational constraints on secondary organic aerosol formation and oxidation processes, since this molecule has been proposed to play a crucial role in forming aerosol due to its high water solubility, isomerization, and abundant production from the oxidation of many different volatile organic compounds (VOCs). A box model analysis incorporating secondary glyoxal sources from VOC oxidation and sinks to OH reaction, photolysis and heterogeneous uptake will be used to determine a budget and potential for SOA formation. This work was supported by the National Natural Science Foundation of China (21190052), the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB05010500) and the U.S. National Science Foundation Atmospheric (AGS-1405805).

  14. Two years of MAXDOAS measurements of NO2, HONO, SO2 and HCHO at SORPES station in Nanjing, China

    NASA Astrophysics Data System (ADS)

    Hao, Nan; Ding, Aijun; Van Roozendael, Michel; Hendrick, Francois; Shen, Yicheng; Valks, Pieter

    2015-04-01

    The Yangtze River Delta (YRD) region includes the mega-city Shanghai and the well-industrialized and urbanized areas of Zhejiang Province and Jiangsu Province, with over ten large cities, such as Hangzhou, Suzhou and Nanjing. Covering only 2% land area, this region produces over 20% of China's Gross Domestic Product (GDP) which makes it the most densely populated region and one of the most polluted regions in China. In the YRD region, knowledge gaps still exist in the understanding of the source and transport of air pollutants because only few measurement studies have been conducted. This work presents two years measurements of air pollutants including NO2, HONO, SO2, HCHO and CHOCHO at a regional back-ground site, the Station for Observing Regional Processes of the Earth System (SORPES), in the western part of the Yangtze River Delta (YRD) in eastern China. A retrieval algorithm, based on an on-line implementation of the radiative transfer code LIDORT and the optimal estimation technique, has been used to provide information on trace gases vertical profiles and vertical column densities (VCDs). The seasonal and diurnal cycles of trace gases have been studies and compared with in situ measurements. The retrieved tropospheric NO2, HCHO and SO2 VCDs were compared to satellite measurements, while the NO2 and SO2 near surface concentrations (0-200 m layer) were compared to measurements from in situ instruments at SORPES.

  15. Evaluating the time and source of hydrocarbon additions to soils using lead isotopes and historical changes in industrial lead sources

    SciTech Connect

    Hurst, R.W. California State Univ., Los Angeles, CA )

    1994-04-01

    Isotopic analysis of anthropogenic Pb in well-dated, southern California coastal sediments have been integrated with historical changes in ore Pb sources to produce calibration curves (206Pb/207Pb vs. time) that allow us to model the time anthropogenic Pb was added to a soil horizon. The major, historical sources of anthropogenic Pb in southern California are fossil fuels (e.g. gasoline). Hence, Pb model ages (LABILE model; Los Angeles Borderland Industrial Lead) provide time constraints on Pb deposition from fossil fuel combustion via airborne deposition, runoff, and/or sewage outfall in this region. The correlation between the LABILE model age and known times of anthropogenic Pb additions at 17 specific sites is good (r = 0.978); the accuracy of the method ranges from one to five years in the post-1960 time interval. Factors influencing accuracy include analytical uncertainties in Pb isotopic measurements ([<=]0.1%), the scatter in isotopic ratios of anthropogenic Pb (circa 0.2%), and the uncertainty in the sediment age used to calibrate the method (0-15 yr). At one site three statistically distinguishable events were identified; they correlate with residential development (1968), airborne vehicular Pb deposition (1983), and site remediation (1991). Gasoline incursions at two tests sites have been dated accurately ([+-] 1 yr). The limitations of the LABILE model (geographic, age, types of hydrocarbons, and industry to which it applies) are now under investigation.

  16. Measuring Outcomes in Mental Health Services for Older People: An Evaluation of the Health of the Nation Outcome Scales for Elderly People (HoNOS65+)

    ERIC Educational Resources Information Center

    Gee, Susan B.; Croucher, Matthew J.; Beveridge, John

    2010-01-01

    The Health of the Nation Outcome Scales (HoNOS) family of measures is routinely used in mental health services in the New Zealand, Australia, and the United Kingdom. However, the psychometric properties of the HoNOS65+ for elderly people have not been extensively evaluated. The aim of the present study was to examine the validity, reliability, and…

  17. Aqueous-phase story of isoprene - A mini-review and reaction with HONO

    NASA Astrophysics Data System (ADS)

    Rudziński, Krzysztof J.; Szmigielski, Rafał; Kuznietsova, Inna; Wach, Paulina; Staszek, Dorota

    2016-04-01

    Isoprene is a major biogenic hydrocarbon emitted to the atmosphere and a well-recognized player in atmospheric chemistry, formation of secondary organic aerosol and air quality. Most of the scientific work on isoprene has focused on the gas-phase and smog chamber processing while direct aqueous chemistry has escaped the major attention because physical solubility of isoprene in water is low. Therefore, this work recollects the results of genuine research carried on atmospherically relevant aqueous-phase transformations of isoprene. It clearly shows that isoprene dissolves in water and reacts in aqueous solutions with common atmospheric oxidants such as hydrogen peroxide, ozone, hydroxyl radicals, sulfate radicals and sulfite radicals. The reactions take place in the bulk of solutions or on the gas-liquid interfaces and often are acid-catalyzed and/or enhanced by light. The review is appended by an experimental study of the aqueous-phase reaction of isoprene with nitrous acid (HONO). The decay of isoprene and formation of new products are demonstrated. The tentative chemical mechanism of the reaction is suggested, which starts with slow decomposition of HONO to NO2 and NO. The aqueous chemistry of isoprene explains the formation of a few tropospheric components identified by scientists yet considered of unknown origin. The reaction of isoprene with sulfate radicals explains formation of the MW 182 organosulfate found in ambient aerosol and rainwater while the reaction of isoprene with HONO explains formation of the MW 129 and MW 229 nitroorganic compounds identified in rainwater. Thus, aqueous transformations of isoprene should not be neglected without evidence but rather considered and evaluated in modeling of atmospheric chemical processes even if alternative and apparently dominant heterogeneous pathways of isoprene transformation, dry or wet, are demonstrated.

  18. Measurement of nitrous acid (HONO) by external-cavity quantum cascade laser based quartz-enhanced photoacoustic absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Yi, Hongming; Maamary, Rabih; Gao, Xiaoming; Sigrist, Markus W.; Fertein, Eric; Chen, Weidong

    2016-04-01

    Spectroscopic detection of short-lived gaseous nitrous acid (HONO) at 1254.85 cm-1 was realized by off-beam coupled quartz-enhanced photoacoustic spectroscopy (QEPAS) in conjunction with an external cavity quantum cascade lasers (EC-QCL). High sensitivity monitoring of HONO was performed within a very small gas-sample volume (of ~40 mm3) allowing a significant reduction (of about 4 orders of magnitude) of air sampling residence time which is highly desired for accurate quantification of chemically reactive short-lived species. Calibration of the developed QEPAS-based HONO sensor was carried out by means of lab-generated HONO samples whose concentrations were determined by simultaneous measurements of direct HONO absorption spectra in a 109.5 m multipass cell using a distributed feedback (DBF) QCL. A minimum detection limit (MDL @ SNR=1) of 66 ppbv HONO was achieved at 70 mbar using a laser output power of 50 mW and 1 s integration time, which corresponded to a normalized noise equivalent absorption coefficient of 3.6×10-8 cm-1.W/Hz1/2. This MDL was down to 7 ppbv at the optimal integration time of 150 s. The corresponding minimum detected absorption coefficient (SNR=1) is ~1.1×10-7 cm-1 (MDL: ~3 ppbv) in 1 s and ~1.1×10-8 cm-1 (MDL~330 pptv) in 150 s, respectively, with 1 W laser power. Acknowledgements The authors acknowledge financial supports from the CaPPA project (ANR-10-LABX-005) and the CPER CLIMIBIO program. References H. Yi, R. Maamary, X. Gao, M. W. Sigrist, E. Fertein, W. Chen, "Short-lived species detection of nitrous acid by external-cavity quantum cascade laser based quartz-enhanced photoacoustic absorption spectroscopy", Appl. Phys. Lett. 106 (2015) 101109

  19. Evidence for an Additional Heat Source in the Warm Ionized Medium of Galaxies

    NASA Astrophysics Data System (ADS)

    Reynolds, R. J.; Haffner, L. M.; Tufte, S. L.

    1999-11-01

    Spatial variations of the [S II]/Hα and [N II]/Hα line intensity ratios observed in the gaseous halo of the Milky Way and other galaxies are inconsistent with pure photoionization models. They appear to require a supplemental heating mechanism that increases the electron temperature at low densities, ne. This would imply that in addition to photoionization, which has a heating rate per unit volume proportional to n2e, there is another source of heat with a rate per unit volume proportional to a lower power of ne. One possible mechanism is the dissipation of interstellar plasma turbulence, which, according to Minter & Spangler, heats the ionized interstellar medium in the Milky Way at a rate of ~1×10-25ne ergs cm-3 s-1. If such a source were present, it would dominate over photoionization heating in regions where ne<~0.1 cm-3, producing the observed increases in the [S II]/Hα and [N II]/Hα intensity ratios at large distances from the galactic midplane as well as accounting for the constancy of [S II]/[N II], which is not explained by pure photoionization. Other supplemental heating sources, such as magnetic reconnection, cosmic rays, or photoelectric emission from small grains, could also account for these observations, provided they supply ~10-5 ergs s-1 per square centimeter of the Galactic disk to the warm ionized medium.

  20. Accelerated Source-Encoding Full-Waveform Inversion with Additional Constraints

    NASA Astrophysics Data System (ADS)

    Boehm, C.; Fichtner, A.; Ulbrich, M.

    2014-12-01

    We present a flexible framework of Newton-type methods for constrained full-waveform inversion in the time domain. Our main goal is (1) to incorporate additional prior knowledge by using general constraints on the model parameters and (2) to reduce the computational costs of solving the inverse problem by tailoring source-encoding strategies to Newton-type methods.In particular, we apply the Moreau-Yosida regularization to handle the constraints and use a continuation strategy to adjust the regularization parameter. Furthermore, we propose a semismooth Newton method with a trust-region globalization that relies on second-order adjoints to compute the Newton system with a matrix-free preconditioned conjugate gradient solver. The costs of conventional FWI approaches scale proportionally with the number of seismic sources. Here, source-encoding strategies that trigger different sources simultaneously have been proven to be a successful tool to trade a small loss of information for huge savings of computational time to solve the inverse problem. This is particularly interesting for our setting as one iteration of Newton's methods using the full Hessian is considerably more expensive than quasi-Newton methods like L-BFGS. To this end, we discuss a sample average approximation model that is accelerated by using inexact Hessian information based on mini-batches of the samples. Furthermore, we compare its performance with stochastic descent schemes. Here, the classical stochastic gradient method is accelerated by an L-BFGS preconditioner and moreover, the stability of this stochastic preconditioner is enhanced by using the Hessian instead of only gradient information.Numerical results are presented for problems in geophysical exploration on reservoir-scale.

  1. A method for the measurement of atmospheric HONO based on DNPH derivatization and HPLC analysis

    SciTech Connect

    Zhou, X.; Qiao, H.; Deng, G.; Civerolo, K.

    1999-10-15

    A simple measurement technique was developed for atmospheric HONO based on aqueous scrubbing using a coil sampler followed by 2,4-dinitrophenylhydrazine (DNPH) derivatization and high-performance liquid chromatographic (HPLC) analysis. Quantitative sampling efficiency was obtained using a 1 mM phosphate buffer, pH 7.0, as the scrubbing solution at a gas sampling flow rate of 2 L min{sup {minus}1} and a liquid flow rate of 0.24 mL min{sup {minus}1}. Derivation of the scrubbed nitrous acid by DNPH was fast and was completed within 5 min in a derivatization medium containing 300 {micro}M DNPH and 8 mM HCI at 45 C. The azide derivative was separated from DNPH reagent and carbonyl derivatives by reverse-phase HPLC and was detected with an UV detector at 309 nm. The detection limit is {le}5 pptv and may be lowered to 1 pptv with further DNPH purification. Interferences from NO, NO{sub 2} PAN, O{sub 3}, HNO{sub 3}, and HCHO were studied and found to be negligible. Ambient HONO concentration was measured simultaneously in downtown Albany, NY, by this method and by an ion chromatographic technique after sampling using a fritted bubbler. The results, from 70 pptv during the day to 1.7 ppbv in the early morning, were in very good agreement from the two techniques, within {+-} 20%.

  2. Statistical addition method for external noise sources affecting HF-MF-LF systems

    NASA Astrophysics Data System (ADS)

    Neudegg, David

    2001-01-01

    The current statistical method for the addition of external component noise sources in the LF, MF, and lower HF band (100 kHz to 3 MHz) produces total median noise levels that may be less than the largest-component median in some cases. Several case studies illustrate this anomaly. Methods used to sum the components rely on their power (decibels) distributions being represented as normal by the statistical parameters. The atmospheric noise component is not correctly represented by its decile values when it is assumed to have a normal distribution, causing anomalies in the noise summation when components are similar in magnitude. A revised component summation method is proposed, and the way it provides a more physically realistic total noise median for LF, MF, and lower HF frequencies is illustrated.

  3. Key role of pH in the photochemical conversion of NO2 to HONO on humic acid

    NASA Astrophysics Data System (ADS)

    Han, Chong; Yang, Wangjin; Wu, Qianqian; Yang, He; Xue, Xiangxin

    2016-10-01

    The heterogeneous photochemical reactions of NO2 with humic acid (HA) were performed using a flow tube reactor coupled to a NOx analyzer. The effects of the pH on the uptake coefficient (γ) of NO2 and HONO and NO yields were investigated in detail. With increasing the pH in the range of 2-12, γ was almost constant with an average value of (4.21 ± 0.46) × 10-6, whereas the HONO yield and NO yield linearly decreased from (81.07 ± 4.07)% and (10.35 ± 3.86)% to (13.87 ± 9.15)% and (1.51 ± 0.94)%, respectively. According to the characterization of HA compositions and possible reaction paths, it can be concluded that the pH may influence the transfer of protons and the equilibrium of HONO with NO2- by varying the contents of carboxyl and phenol groups in HA, which should primarily contribute to the change in the HONO yield with the pH.

  4. NitroMAC: An instrument for the measurement of HONO and intercomparison with a long-path absorption photometer.

    PubMed

    Afif, Charbel; Jambert, Corinne; Michoud, Vincent; Colomb, Aurélie; Eyglunent, Gregory; Borbon, Agnès; Daële, Véronique; Doussin, Jean-François; Perros, Pascal

    2016-02-01

    NitroMAC (French acronym for continuous atmospheric measurements of nitrogenous compounds) is an instrument which has been developed for the semi-continuous measurement of atmospheric nitrous acid (HONO). This instrument relies on wet chemical sampling and detection using high performance liquid chromatography (HPLC)-visible absorption at 540 nm. Sampling proceeds by dissolution of gaseous HONO in a phosphate buffer solution followed by derivatization with sulfanilamide/N-(1-naphthyl)-ethylenediamine. The performance of this instrument was found to be as follows: a detection limit of around 3 ppt with measurement uncertainty of 10% over an analysis time of 10 min. Intercomparison was made between the instrument and a long-path absorption photometer (LOPAP) during two experiments in different environments. First, air was sampled in a smog chamber with concentrations up to 18 ppb of nitrous acid. NitroMAC and LOPAP measurements showed very good agreement. Then, in a second experiment, ambient air with HONO concentrations below 250 ppt was sampled. While NitroMAC showed its capability of measuring HONO in moderate and highly polluted environments, the intercomparison results in ambient air highlighted that corrections must be made for minor interferences when low concentrations are measured.

  5. Elite sport is not an additional source of distress for adolescents with high stress levels.

    PubMed

    Gerber, Markus; Holsboer-Trachsler, Edith; Pühse, Uwe; Brand, Serge

    2011-04-01

    This study examined whether participation in elite sport interacts with stress in decreasing or increasing symptoms of depression and anxiety among adolescents, and further, whether the interplay between participation in high-performance sport and stress is related to the perceived quality of sleep. 434 adolescents (278 girls, 156 boys; age: M = 17.2 yr.) from 15 "Swiss Olympic Sport Classes" and 9 conventional classes answered a questionnaire and completed a 7-day sleep log. Analyses of covariance showed that heightened stress was related to more depressive symptoms and higher scores for trait-anxiety. Moreover, those classified as having poor sleep by a median split cutoff reported higher levels of depressive symptoms. No significant (multivariate) main effects were found for high-performance sport athletes. Similarly, no significant two- or three-way interaction effects were found. These results caution against exaggerated expectations concerning sport participation as a stress buffer. Nevertheless, participation in high-performance sport was not found to be an additional source of distress for adolescents who reported high stress levels despite prior research that has pointed toward such a relationship.

  6. Solar neutrinos and the influences of opacity, thermal instability, additional neutrino sources, and a central black hole on solar models

    NASA Technical Reports Server (NTRS)

    Stothers, R. B.; Ezer, D.

    1972-01-01

    Significant quantities that affect the internal structure of the sun are examined for factors that reduce the temperature near the sun's center. The four factors discussed are: opacity, central black hole, thermal instability, and additional neutrino sources.

  7. ADDITIONAL OBSERVATIONS OF PLANETS AND QUASI-STELLAR RADIO SOURCES AT 3 MM,

    DTIC Science & Technology

    MERCURY ( PLANET ), VENUS( PLANET ), PERIODIC VARIATIONS, RADIO ASTRONOMY, SPECTRUM SIGNATURES...EXTRATERRESTRIAL RADIO WAVES, SOURCES), GALAXIES, BLACKBODY RADIATION, BRIGHTNESS, TEMPERATURE, MARS( PLANET ), JUPITER( PLANET ), SATURN( PLANET

  8. Investigation of effective line intensities of trans-HONO near 1255 cm-1 using continuous-wave quantum cascade laser spectrometers

    NASA Astrophysics Data System (ADS)

    Cui, Xiaojuan; Dong, Fengzhong; Sigrist, Markus W.; Zhang, Zhirong; Wu, Bian; Xia, Hua; Pang, Tao; Sun, Pengshuai; Fertein, Eric; Chen, Weidong

    2016-10-01

    Effective line intensities of P branch transitions of trans-nitrous acid (HONO) in the ν3 H-O-N bending mode near 1255 cm-1 have been determined by scaling measured HONO absorption intensities by continuous-wave quantum cascade laser absorption spectroscopy to reference values. Gaseous HONO samples were synthetized in the laboratory using the reaction of H2SO4 and NaNO2 solutions and the heterogeneous formation on surfaces in the presence of ambient water vapor and NO2 gas in a sealed gas sampling bag. The quantification of HONO was performed using a denuder associated with a NOx analyzer. Observed absorption line strengths for the trans conformer are found to be by a factor of approximately 1.17 higher than previously reported line strengths.

  9. Meta-analysis on Methane Mitigating Properties of Saponin-rich Sources in the Rumen: Influence of Addition Levels and Plant Sources

    PubMed Central

    Jayanegara, Anuraga; Wina, Elizabeth; Takahashi, Junichi

    2014-01-01

    Saponins have been considered as promising natural substances for mitigating methane emissions from ruminants. However, studies reported that addition of saponin-rich sources often arrived at contrasting results, i.e. either it decreased methane or it did not. The aim of the present study was to assess ruminal methane emissions through a meta-analytical approach of integrating related studies from published papers which described various levels of different saponin-rich sources being added to ruminant feed. A database was constructed from published literature reporting the addition of saponin-rich sources at various levels and then monitoring ruminal methane emissions in vitro. Accordingly, levels of saponin-rich source additions as well as different saponin sources were specified in the database. Apart from methane, other related rumen fermentation parameters were also included in the database, i.e. organic matter digestibility, gas production, pH, ammonia concentration, short-chain fatty acid profiles and protozoal count. A total of 23 studies comprised of 89 data points met the inclusion criteria. The data obtained were subsequently subjected to a statistical meta-analysis based on mixed model methodology. Accordingly, different studies were treated as random effects whereas levels of saponin-rich source additions or different saponin sources were considered as fixed effects. Model statistics used were p-value and root mean square error. Results showed that an addition of increasing levels of a saponin-rich source decreased methane emission per unit of substrate incubated as well as per unit of total gas produced (p<0.05). There was a decrease in acetate proportion (linear pattern; p<0.001) and an increase in propionate proportion (linear pattern; p<0.001) with increasing levels of saponin. Log protozoal count decreased (p<0.05) at higher saponin levels. Comparing between different saponin-rich sources, all saponin sources, i.e. quillaja, tea and yucca saponins

  10. A semiclassical study of cis-trans isomerization in HONO using an interpolating moving least-squares potential

    NASA Astrophysics Data System (ADS)

    Pham, Phong; Guo, Yin

    2013-04-01

    The interpolating moving least-squares (IMLS) approach for constructing potential energy surfaces has been developed and employed in standard classical trajectory simulations in the past few years. We extend the approach to the tunneling regime by combining the IMLS fitting method and the semiclassical scheme that incorporates tunneling into classical trajectory calculations. Dynamics of cis-trans isomerization in nitrous acid (HONO) is studied as a test case to investigate various aspects of the approach such as the strategy for growing the surface, the basis set employed, the scaling of the IMLS fits, and the accuracy of the surface required for obtaining converged rate coefficients. The validity of the approach is demonstrated through comparison with other semiclassical and quantum mechanical studies on HONO.

  11. Impacts of carbon source addition on denitrification and phosphorus uptake in enhanced biological phosphorus removal systems.

    PubMed

    Begum, Shamim A; Batista, Jacimaria R

    2013-01-01

    In this study, simultaneous denitrification and phosphorus (P) removal were investigated in batch tests using nitrified mixed liquor and secondary wastewater influent from a full-scale treatment plant and different levels of acetate and propionate as supplemental carbon sources. Without supplemental carbon source, denitrification occurred at low rate and P release and P uptake was negatively affected (i.e., P removal of only 59.7%). When acetate and propionate were supplied, denitrification and P release occurred simultaneously under anoxic conditions. For acetate and propionate at a C/N stoichiometric ratio of 7.6, P release was negatively affected by denitrification. For acetate, the percent P removal and denitrification were very similar for C/N ratios of 22 (5X stoichiometric) and 59 (10X stoichiometric). For propionate, both percent P removal and denitrification deteriorated for C/N ratios of 22 (5X stoichiometric) and 45 (10X stoichiometric). It was observed that carbon source added in excess to stoichiometric ratio was consumed in the aerobic zone, but P was not taken up. This implies that PAO bacteria may utilize the excess carbon source in the aerobic zone rather than their polyhydroxyalkanoate (PHA) reserves, thereby promoting deterioration of the system.

  12. A radio/optical reference frame. 5: Additional source positions in the mid-latitude southern hemisphere

    NASA Technical Reports Server (NTRS)

    Russell, J. L.; Reynolds, J. E.; Jauncey, D. L.; De Vegt, C.; Zacharias, N.; Ma, C.; Fey, A. L.; Johnston, K. J.; Hindsley, R.; Hughes, J. A.

    1994-01-01

    We report new accurate radio position measurements for 30 sources, preliminary positions for two sources, improved radio postions for nine additional sources which had limited previous observations, and optical positions and optical-radio differences for six of the radio sources. The Very Long Baseline Interferometry (VLBI) observations are part of the continuing effort to establish a global radio reference frame of about 400 compact, flat spectrum sources, which are evenly distributed across the sky. The observations were made using Mark III data format in four separate sessions in 1988-89 with radio telescopes at Tidbinbilla, Australia, Kauai, USA, and Kashima, Japan. We observed a total of 54 sources, including ten calibrators and three which were undetected. The 32 new source positions bring the total number in the radio reference frame catalog to 319 (172 northern and 147 southern) and fill in the zone -25 deg greater than delta greater than -45 deg which, prior to this list, had the lowest source density. The VLBI positions have an average formal precision of less than 1 mas, although unknown radio structure effects of about 1-2 mas may be present. The six new optical postion measurements are part of the program to obtain positions of the optical counterparts of the radio reference frame source and to map accurately the optical on to the radio reference frames. The optical measurements were obtained from United States Naval Observatory (USNO) Black Birch astrograph plates and source plates from the AAT, and Kitt Peak National Observatory (KPNO) 4 m, and the European Southern Observatory (ESO) Schmidt. The optical positions have an average precision of 0.07 sec, mostly due to the zero point error when adjusted to the FK5 optical frame using the IRS catalog. To date we have measured optical positions for 46 sources.

  13. Common genetic variants, acting additively, are a major source of risk for autism

    PubMed Central

    2012-01-01

    Background Autism spectrum disorders (ASD) are early onset neurodevelopmental syndromes typified by impairments in reciprocal social interaction and communication, accompanied by restricted and repetitive behaviors. While rare and especially de novo genetic variation are known to affect liability, whether common genetic polymorphism plays a substantial role is an open question and the relative contribution of genes and environment is contentious. It is probable that the relative contributions of rare and common variation, as well as environment, differs between ASD families having only a single affected individual (simplex) versus multiplex families who have two or more affected individuals. Methods By using quantitative genetics techniques and the contrast of ASD subjects to controls, we estimate what portion of liability can be explained by additive genetic effects, known as narrow-sense heritability. We evaluate relatives of ASD subjects using the same methods to evaluate the assumptions of the additive model and partition families by simplex/multiplex status to determine how heritability changes with status. Results By analyzing common variation throughout the genome, we show that common genetic polymorphism exerts substantial additive genetic effects on ASD liability and that simplex/multiplex family status has an impact on the identified composition of that risk. As a fraction of the total variation in liability, the estimated narrow-sense heritability exceeds 60% for ASD individuals from multiplex families and is approximately 40% for simplex families. By analyzing parents, unaffected siblings and alleles not transmitted from parents to their affected children, we conclude that the data for simplex ASD families follow the expectation for additive models closely. The data from multiplex families deviate somewhat from an additive model, possibly due to parental assortative mating. Conclusions Our results, when viewed in the context of results from genome

  14. Effect of SO2 concentration on SOA formation in a photorreactor from a mixture of anthropogenic hydrocarbons and HONO

    NASA Astrophysics Data System (ADS)

    García Vivanco, Marta; Santiago, Manuel; García Diego, Cristina; Borrás, Esther; Ródenas, Milagros; Martínez-Tarifa, Adela

    2010-05-01

    Sulfur dioxide (SO2) is an important urban atmospheric pollutant, mainly produced by the combustion of fossil fuels containing sulfur. In the atmosphere, SO2 can react with OH radicals to form sulfuric acid, which can condense to form acidic aerosol. Sulfuric acid particles act as an acid catalyst for some heterogeneous carbonyl reactions like hydration, polymerization or acetals formation, which may lead to a large increase on SOA mass. In order to evaluate the effect of the SO2 concentration on SOA formation, 3 experiments were performed during the campaign carried out by CIEMAT on the EUPHORE facility (CEAM, Valencia, Spain) during June- July 2008. The objective of the campaign was to evaluate the effect of different experimental conditions on SOA formation from the photooxidation of some anthropogenic and biogenic VOCs using HONO as oxidant. Experiment on 6/17/08 was selected as base case (no SO2 was introduced) and experiments 6/26/08 and 7/1/08 were selected as high SO2 (2600 ug/m3) and low SO2 (60 ug/m3) concentration experiments respectively. In the three experiments a mixture of toluene, 1,3,5-TMB (trimethylbenzene), o-xylene and octane was selected as the parent VOCs. Single and coupled to mass spectroscopy gas cromatography (GC and GC/MS), as well as high performance liquid chromatography (HPLC) and Fourier transform infrared spectroscopy (FTIR) were used to measure the initial VOCs and oxidant concentrations decay and the formation of gas phase oxidation products through the experiments. Aerosol size distribution and concentration were measured with SMPS (scanning mobility particle sizer) and TEOM (tapered element oscillating monitor) respectively. In addition, analysis of the organic and inorganic aerosol content was also performed via filter sampling followed by GC/MS and ionic chromatography (for organic and inrganic content respectively). Comparing the filters collected in the three experiments, clearly the largest mass aerosol formation is observed

  15. Wood decomposition in Amazonian hydropower reservoirs: An additional source of greenhouse gases

    NASA Astrophysics Data System (ADS)

    Abril, Gwenaël; Parize, Marcelo; Pérez, Marcela A. P.; Filizola, Naziano

    2013-07-01

    Amazonian hydroelectric reservoirs produce abundant carbon dioxide and methane from large quantities of flooded biomass that decompose anaerobically underwater. Emissions are extreme the first years after impounding and progressively decrease with time. To date, only water-to-air fluxes have been considered in these estimates. Here, we investigate in two Amazonian reservoirs (Balbina and Petit Saut) the fate of above water standing dead trees, by combining a qualitative analysis of wood state and density through time and a quantitative analysis of the biomass initially flooded. Dead wood was much more decomposed in the Balbina reservoir 23 years after flooding than in the Petit Saut reservoir 10 years after flooding. Termites apparently played a major role in wood decomposition, occurring mainly above water, and resulting in a complete conversion of this carbon biomass into CO2 and CH4 at a timescale much shorter than reservoir operation. The analysis of pre-impounding wood biomass reveals that above-water decomposition in Amazonian reservoirs is a large, previously unrecognized source of carbon emissions to the atmosphere, representing 26-45% of the total reservoir flux integrated over 100 years. Accounting for both below- and above-water fluxes, we could estimate that each km2 of Amazonian forest converted to reservoir would emit over 140 Gg CO2-eq in 100 years. Hydropower plants in the Amazon should thus generate 0.25-0.4 MW h per km2 flooded area to produce lower greenhouse gas emissions than gas power plants. They also have the disadvantage to emit most of their greenhouse gases the earliest years of operation.

  16. Sump additives as a source of bioaerosols in a school building.

    PubMed

    Thorne, P S

    1993-04-01

    An investigation was launched following complaints of poor air quality and building-related illness in a public elementary school. Occlusion of air intakes put the building under negative pressure and caused vents from a below-ground sump to become air intakes. Outside air drawn through the sump pit traveled into the adjacent main air handling unit and was disseminated throughout the building. Sump additives introduced in an attempt to counteract foul odors contained spores of Bacillus species, which appeared as bioaerosols throughout the school. Viable microbial sampling identified B subtilis, B cereus, and B licheniformis in the sump room and classrooms at levels as high as 760 colony forming units/m3 (CFU/m3). Concentrations of CO2 in classrooms were 1250 ppm, indicating inadequate makeup air. Remediation was accomplished by opening the air intakes, isolating the sump room from the air handling system, venting the sump to the outside, and flushing the sump with fresh water on a regular basis.

  17. High Temperature Thermoplastic Additive Manufacturing Using Low-Cost, Open-Source Hardware

    NASA Technical Reports Server (NTRS)

    Gardner, John M.; Stelter, Christopher J.; Yashin, Edward A.; Siochi, Emilie J.

    2016-01-01

    Additive manufacturing (or 3D printing) via Fused Filament Fabrication (FFF), also known as Fused Deposition Modeling (FDM), is a process where material is placed in specific locations layer-by-layer to create a complete part. Printers designed for FFF build parts by extruding a thermoplastic filament from a nozzle in a predetermined path. Originally developed for commercial printers, 3D printing via FFF has become accessible to a much larger community of users since the introduction of Reprap printers. These low-cost, desktop machines are typically used to print prototype parts or novelty items. As the adoption of desktop sized 3D printers broadens, there is increased demand for these machines to produce functional parts that can withstand harsher conditions such as high temperature and mechanical loads. Materials meeting these requirements tend to possess better mechanical properties and higher glass transition temperatures (Tg), thus requiring printers with high temperature printing capability. This report outlines the problems and solutions, and includes a detailed description of the machine design, printing parameters, and processes specific to high temperature thermoplastic 3D printing.

  18. Source Distribution Method for Unsteady One-Dimensional Flows With Small Mass, Momentum, and Heat Addition and Small Area Variation

    NASA Technical Reports Server (NTRS)

    Mirels, Harold

    1959-01-01

    A source distribution method is presented for obtaining flow perturbations due to small unsteady area variations, mass, momentum, and heat additions in a basic uniform (or piecewise uniform) one-dimensional flow. First, the perturbations due to an elemental area variation, mass, momentum, and heat addition are found. The general solution is then represented by a spatial and temporal distribution of these elemental (source) solutions. Emphasis is placed on discussing the physical nature of the flow phenomena. The method is illustrated by several examples. These include the determination of perturbations in basic flows consisting of (1) a shock propagating through a nonuniform tube, (2) a constant-velocity piston driving a shock, (3) ideal shock-tube flows, and (4) deflagrations initiated at a closed end. The method is particularly applicable for finding the perturbations due to relatively thin wall boundary layers.

  19. Utility of the Health of the Nation Outcome Scales (HoNOS) in Predicting Mental Health Service Costs for Patients with Common Mental Health Problems: Historical Cohort Study

    PubMed Central

    Twomey, Conal; Prina, A. Matthew; Baldwin, David S.; Das-Munshi, Jayati; Kingdon, David; Koeser, Leonardo; Prince, Martin J.; Stewart, Robert; Tulloch, Alex D.; Cieza, Alarcos

    2016-01-01

    Background Few countries have made much progress in implementing transparent and efficient systems for the allocation of mental health care resources. In England there are ongoing efforts by the National Health Service (NHS) to develop mental health ‘payment by results’ (PbR). The system depends on the ability of patient ‘clusters’ derived from the Health of the Nation Outcome Scales (HoNOS) to predict costs. We therefore investigated the associations of individual HoNOS items and the Total HoNOS score at baseline with mental health service costs at one year follow-up. Methods An historical cohort study using secondary care patient records from the UK financial year 2012–2013. Included were 1,343 patients with ‘common mental health problems’, represented by ICD-10 disorders between F32-48. Costs were based on patient contacts with community-based and hospital-based mental health services. The costs outcome was transformed into ‘high costs’ vs ‘regular costs’ in main analyses. Results After adjustment for covariates, 11 HoNOS items were not associated with costs. The exception was ‘self-injury’ with an odds ratio of 1.41 (95% CI 1.10–2.99). Population attributable fractions (PAFs) for the contribution of HoNOS items to high costs ranged from 0.6% (physical illness) to 22.4% (self-injury). After adjustment, the Total HoNOS score was not associated with costs (OR 1.03, 95% CI 0.99–1.07). However, the PAF (33.3%) demonstrated that it might account for a modest proportion of the incidence of high costs. Conclusions Our findings provide limited support for the utility of the self-injury item and Total HoNOS score in predicting costs. However, the absence of associations for the remaining HoNOS items indicates that current PbR clusters have minimal ability to predict costs, so potentially contributing to a misallocation of NHS resources across England. The findings may inform the development of mental health payment systems internationally

  20. Modeling the Effect of External Carbon Source Addition under Different Electron Acceptor Conditions in Biological Nutrient Removal Activated Sludge Systems.

    PubMed

    Hu, Xiang; Wisniewski, Kamil; Czerwionka, Krzysztof; Zhou, Qi; Xie, Li; Makinia, Jacek

    2016-02-16

    The aim of this study was to expand the International Water Association Activated Sludge Model No. 2d (ASM2d) to predict the aerobic/anoxic behavior of polyphosphate accumulating organisms (PAOs) and "ordinary" heterotrophs in the presence of different external carbon sources and electron acceptors. The following new aspects were considered: (1) a new type of the readily biodegradable substrate, not available for the anaerobic activity of PAOs, (2) nitrite as an electron acceptor, and (3) acclimation of "ordinary" heterotrophs to the new external substrate via enzyme synthesis. The expanded model incorporated 30 new or modified process rate equations. The model was evaluated against data from several, especially designed laboratory experiments which focused on the combined effects of different types of external carbon sources (acetate, ethanol and fusel oil) and electron acceptors (dissolved oxygen, nitrate and nitrite) on the behavior of PAOs and "ordinary" heterotrophs. With the proposed expansions, it was possible to improve some deficiencies of the ASM2d in predicting the behavior of biological nutrient removal (BNR) systems with the addition of external carbon sources, including the effect of acclimation to the new carbon source.

  1. Xylem-Transported Glucose as an Additional Carbon Source for Leaf Isoprene Formation in Quercus Robur L.

    NASA Astrophysics Data System (ADS)

    Graus, M.; Kreuzwieser, J.; Schnitzler, J.; Wisthaler, A.; Hansel, A.; Rennenberg, H.

    2003-04-01

    Isoprene is emitted from mature, photosynthesizing leaves of many plant species, particularly of trees. Current interest in understanding the biochemical and physiological mechanisms controlling isoprene formation is caused by the important role isoprene plays in atmospheric chemistry. Isoprene reacts with hydroxyl radicals (OH) thereby generating oxidizing agents such as ozone and organic peroxides. Ozone causes significant deterioration in air quality and can pose threats to human health therefore its control is a major goal in Europe and the United States. In recent years, much progress has been made in elucidating the pathways of isoprene biosynthesis. Nevertheless the regulatory mechanisms controlling isoprene emission are not completely understood. Light and temperature appear to be the main factors controlling short-term variations in isoprene emission. Exposure of plants to C-13 labeled carbon dioxide showed instantaneous assimilated carbon is the primary carbon source for isoprene formation. However, variations in diurnal and seasonal isoprene fluxes, which cannot be explained by temperature, light, and leaf development led to the suggestion that alternative carbon sources may exist contributing to isoprene emissions. The aim of the present study was to test whether xylem-transported carbohydrates act as additional sources for isoprene biosynthesis. For this purpose, [U-C-13] alpha-D-glucose was fed to photosynthesizing leaves via the xylem of Quercus robur L. seedlings and the incorporation of glucose derived C-13 into emitted isoprene was monitored in real time using Proton-Transfer-Reaction Mass Spectrometry (PTR-MS). A rapid incorporation of C-13 from xylem-fed glucose into single (mass 70) and double (mass 71) C-13 labeled isoprene molecules was observed after a lag phase of approximately 5 to 10 minutes. This incorporation was temperature dependent and was highest (up to 13% C-13 of total carbon emitted as isoprene) at the temperature optimum of

  2. Xylem-transported Glucose as an Additional Carbon Source for Leaf Isoprene Formation in Quercus Robur L.

    NASA Astrophysics Data System (ADS)

    Graus, M.; Wisthaler, A.; Hansel, A.; Kreuzwieser, J.; Rennenberg, H.; Schnitzler, J.

    2002-12-01

    Isoprene is emitted from mature, photosynthesizing leaves of many plant species, particularly of trees. Current interest in understanding the biochemical and physiological mechanisms controlling isoprene formation is caused by the important role isoprene plays in atmospheric chemistry. Isoprene reacts with hydroxyl radicals (OH) thereby generating oxidizing agents such as ozone and organic peroxides. Ozone causes significant deterioration in air quality and can pose threats to human health therefore its control is a major goal in Europe and the United States. In recent years, much progress has been made in elucidating the pathways of isoprene biosynthesis. Nevertheless the regulatory mechanisms controlling isoprene emission are not completely understood. Light and temperature appear to be the main factors controlling short-term variations in isoprene emission. Exposure of plants to 13CO2 showed instantaneous assimilated carbon is the primary carbon source for isoprene formation. However, variations in diurnal and seasonal isoprene fluxes, which cannot be explained by temperature, light, and leaf development led to the suggestion that alternative carbon sources may exist contributing to isoprene emissions. The aim of the present study was to test whether xylem-transported carbohydrates act as additional sources for isoprene biosynthesis. For this purpose, [U-13C]α-D-glucose was fed to photosynthesizing leaves via the xylem of {Quercus} {robur} L. seedlings and the incorporation of glucose derived 13C into emitted isoprene was monitored in real time using Proton-Transfer-Reaction Mass Spectrometry (PTR-MS). A rapid incorporation of 13C from xylem-fed glucose into single (mass 70) and double (mass 71) 13C-labeled isoprene molecules was observed after a lag phase of approximately 5 to 10 minutes. This incorporation was temperature dependent and was highest (up to 13 % 13C of total carbon emitted as isoprene) at the temperature optimum of isoprene emission (40 - 42

  3. Additively manufactured MEMS multiplexed coaxial electrospray sources for high-throughput, uniform generation of core-shell microparticles.

    PubMed

    Olvera-Trejo, D; Velásquez-García, L F

    2016-10-18

    This study reports the first MEMS multiplexed coaxial electrospray sources in the literature. Coaxial electrospraying is a microencapsulation technology based on electrohydrodynamic jetting of two immiscible liquids, which allows precise control with low size variation of the geometry of the core-shell particles it generates, which is of great importance in numerous biomedical and engineering applications, e.g., drug delivery and self-healing composites. By implementing monolithic planar arrays of miniaturized coaxial electrospray emitters that work uniformly in parallel, the throughput of the compound microdroplet source is greatly increased, making the microencapsulation technology compatible with low-cost commercial applications. Miniaturized core-shell particle generators with up to 25 coaxial electrospray emitters (25 emitters cm(-2)) were fabricated via stereolithography, which is an additive manufacturing process that can create complex microfluidic devices at a small fraction of the cost per device and fabrication time associated with silicon-based counterparts. The characterization of devices with the same emitter structure but different array sizes demonstrates uniform array operation. Moreover, the data demonstrate that the per-emitter current is approximately proportional to the square root of the flow rate of the driving liquid, and it is independent of the flow rate of the driven liquid, as predicted by the theory. The core/shell diameters and the size distribution of the generated compound microparticles can be modulated by controlling the flow rates fed to the emitters.

  4. Reduction of Methane Emission during Slurry Storage by the Addition of Effective Microorganisms and Excessive Carbon Source from Brewing Sugar.

    PubMed

    Bastami, Mohd Saufi B; Jones, Davey L; Chadwick, David R

    2016-11-01

    Storing livestock manure is the primary stage of manure management where microbial processes and chemical reactions result in the release of methane (CH), nitrous oxide (NO), ammonia (NH), and carbon dioxide (CO). This study examined the reduction of CH emissions from slurry storage under two temperatures (cool [10°C] and warm [30°C]) when a glucose-rich substrate (brewing sugar) and activated effective microorganisms were applied at 10% (w/w) and 5% (v/w), respectively. Brewing sugar addition influenced microbial anaerobic respiration, resulting in a reduction of slurry pH to <5.0, through "self-acidification" caused by lactic acid production. Subsequently, CH emissions were significantly reduced by 87 and 99% in the cool and warm environments, respectively. The effective microorganism treatment did not change the chemical characteristics of the slurry but reduced CH emissions by 17 and 27% ( < 0.05) in the cool and warm environments, respectively. These results suggest that self-acidification after addition of a carbon source may be a promising alternative to slurry acidification using concentrated acids.

  5. Addition of a worm leachate as source of humic substances in the drinking water of broiler chickens.

    PubMed

    Gomez-Rosales, S; de L Angeles, M

    2015-02-01

    The objective of this research was to evaluate the growth performance, the apparent ileal digestibility of nitrogen and energy, the retention of nutrients and the apparent metabolizable energy corrected to zero nitrogen retention (AMEn) in broiler chickens supplemented with increasing doses of a worm leachate (WL) as a source of humic substances (HS) in the drinking water. In Exp. 1, 140 male broilers were penned individually and assigned to four WL levels (0%, 10%, 20%, and 30%) mixed in the drinking water from 21 to 49 days of age. Water was offered in plastic bottles tied to the cage. In Exp. 2, 600 male broilers from 21 to 49 days of age housed in floor pens were assigned to three levels of WL (0%, 10%, and 20%) mixed in the drinking water. The WL was mixed with tap water in plastic containers connected by plastic tubing to bell drinkers. The results of both experiments were subjected to analysis of variance and polynomial contrasts. In Exp. 1, the daily water consumption was similar among treatments but the consumption of humic, fulvic, and total humic acids increased linearly (p<0.01) as the WL increased in the drinking water. The feed conversion (p<0.01) and the ileal digestibility of energy, the excretion of dry matter and energy, the retention of dry matter, ash and nitrogen and the AMEn showed quadratic responses (p<0.05) relative to the WL levels in drinking water. In Exp. 2, the increasing level of WL in the drinking water had quadratic effects on the final body weight, daily weight gain and feed conversion ratio (p<0.05). The addition of WL as a source of HS in the drinking water had beneficial effects on the growth performance, ileal digestibility of energy, the retention of nutrients as well on the AMEn in broiler chickens; the best results were observed when the WL was mixed at levels of 20% to 30% in the drinking water.

  6. Field-scale investigation of enhanced petroleum hydrocarbon biodegradation in the vadose zone combining soil venting as an oxygen source with moisture and nutrient addition. Appendices. Doctoral thesis

    SciTech Connect

    Miller, R.N.

    1990-01-01

    This document contains appendices regarding a reprint on a field scale investigation of enhanced petroleum hydrocarbon biodegradation in the vadose zone combining soil venting as a oxygen source with moisture and nutrient addition.

  7. The use of the Health of the Nation Outcome Scales (HoNOS) to inform discharge and transfer decisions in community mental health services.

    PubMed

    Prowse, Liz; Coombs, Tim

    2009-02-01

    Discharge from public community mental health services has proven difficult for mental health workers and managers. Mental illness can often be long term, with ongoing disability, requiring a need for corresponding long-term care. Community mental health services are now becoming recovery focused and are recognising the need for alternative management arrangements for individuals with long-term care needs. There are, however few tools to assist in the decision making about discharge or transfer of care between community mental health teams. This article describes a quality improvement project to develop a flag for mental health workers to prompt decisions regarding discharge and transfer using the Health of the Nation Outcome Scales (HoNOS). Relevant literature and HoNOS data collected as part of routine clinical practice were reviewed to develop the flag. The implementation process is described along with plans for future developments.

  8. Airborne measurements of nitrous acid and its budget in the planetary boundary layer

    NASA Astrophysics Data System (ADS)

    Li, Xin; Häseler, Rolf; Brauers, Theo; Rohrer, Franz; Hofzumahaus, Andreas; Bohn, Birger; Broch, Sebastian; Fuchs, Hendrik; Gomm, Sebastian; Holland, Frank; Lohse, Insa; Tillmann, Ralf; Mentel, Thomas F.; Kiendler-Scharr, Astrid; Wahner, Andreas

    2013-04-01

    Nitrous acid (HONO) is an important trace gas in the atmosphere due to its contribution to the cycles of nitrogen oxides (NOX) and hydrogen oxides (HOX). In the past decades, most HONO observations were performed at ground level, and only a few HONO gradient measurements were reported for the lowest 100 m of the planetary boundary layer (PBL). In most field measurements, it is found that the ambient HONO concentrations cannot be explained by the known gas-phase chemistry alone. Additional HONO production is needed, and heterogeneous production at ground and on aerosol surfaces was proposed. Within the framework of PEGASOS, an instrument for ambient HONO measurement using the LOPAP technique was setup together with instruments measuring HOX radicals, NOX, photolysis frequencies, and other parameters on board the airship Zeppelin NT. During two field campaigns in the Netherlands and in Italy, HONO and its gas phase sources and sinks were measured continuously in each flight, covering the altitude range from ground to 1 km. The measured daytime HONO mixing ratios ranged from 50 ppt to 1.2 ppb with an average value of 140 ppt. While a strong HONO gradient was found in early morning hours, it was vanishing with the breakup of the nocturnal boundary layer. Elevated HONO to NOX ratios were observed at higher altitudes, indicating an enhanced HONO production. HONO simulations using a 1-D model indicate that the HONO production at higher altitudes cannot be explained by known processes, neither by gas-phase reactions nor by vertical mixing of HONO produced at ground surface. Therefore, in addition to the current knowledge of the atmospheric HONO budget, other HONO formation pathways are need to explain the field observations.

  9. 77 FR 12226 - Sadex Corp.; Filing of Food Additive Petition (Animal Use); Electron Beam and X-Ray Sources for...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-29

    ... Petition (Animal Use); Electron Beam and X-Ray Sources for Irradiation of Poultry Feed and Poultry Feed... poultry feed and poultry feed ingredients. DATES: Submit either electronic or written comments on the... use of electron beam and x- ray sources for irradiation of poultry feed and poultry feed...

  10. Biochemical methane potential from sewage sludge: Effect of an aerobic pretreatment and fly ash addition as source of trace elements.

    PubMed

    Huiliñir, César; Pinto-Villegas, Paula; Castillo, Alejandra; Montalvo, Silvio; Guerrero, Lorna

    2017-03-18

    The effect of aerobic pretreatment and fly ash addition on the production of methane from mixed sludge is studied. Three assays with pretreated and not pretreated mixed sludge in the presence of fly ash (concentrations of 0, 10, 25, 50, 250 and 500mg/L) were run at mesophilic condition. It was found that the combined use of aerobic pretreatment and fly ash addition increases methane production up to 70% when the fly ash concentrations were lower than 50mg/L, while concentrations higher than 250mg/L cause up to 11% decrease of methane production. For the anaerobic treatment of mixed sludge without pretreatment, the fly ash improved methane generation at all the concentrations studied, with a maximum of 56%. The removal of volatile solids does not show an improvement compared to the separate use of an aerobic pre-treatment and fly ash addition. Therefore, the combined use of the aerobic pre-treatment and fly ash addition improves only the production of methane.

  11. Recent Additions in the Modeling Capabilities of an Open-Source Wave Energy Converter Design Tool: Preprint

    SciTech Connect

    Tom, N.; Lawson, M.; Yu, Y. H.

    2015-04-20

    WEC-Sim is a midfidelity numerical tool for modeling wave energy conversion devices. The code uses the MATLAB SimMechanics package to solve multibody dynamics and models wave interactions using hydrodynamic coefficients derived from frequency-domain boundary-element methods. This paper presents the new modeling features introduced in the latest release of WEC-Sim. The first feature discussed conversion of the fluid memory kernel to a state-space form. This enhancement offers a substantial computational benefit after the hydrodynamic body-to-body coefficients are introduced and the number of interactions increases exponentially with each additional body. Additional features include the ability to calculate the wave-excitation forces based on the instantaneous incident wave angle, allowing the device to weathervane, as well as import a user-defined wave elevation time series. A review of the hydrodynamic theory for each feature is provided and the successful implementation is verified using test cases.

  12. In situ time-resolved X-ray diffraction of tobermorite formation in autoclaved aerated concrete: Influence of silica source reactivity and Al addition

    SciTech Connect

    Matsui, Kunio; Kikuma, Jun; Tsunashima, Masamichi; Ishikawa, Tetsuji; Matsuno, Shin-ya; Ogawa, Akihiro; Sato, Masugu

    2011-05-15

    The hydrothermal formation of tobermorite during the processing of autoclaved aerated concrete was investigated by in situ X-ray diffraction (XRD) analysis. High-energy X-rays from a synchrotron radiation source in combination with a newly developed autoclave cell and a photon-counting pixel array detector were used. To investigate the effects of the silica source, reactive quartz from chert and less-reactive quartz from quartz sand were used as starting materials. The effect of Al addition on tobermorite formation was also studied. In all cases, C-S-H, hydroxylellestadite and katoite were clearly observed as intermediates. Acceleration of tobermorite formation by Al addition was clearly observed. However, Al addition did not affect the dissolution rate of quartz. Two pathways, via C-S-H and katoite, were also observed in the Al-containing system. These results suggest that the structure of initially formed C-S-H is important for the subsequent tobermorite formation reactions.

  13. Nocturnal Vertical Gradients of O3, NO2, NO3, HONO, HCHO, and SO2 in Los Angeles, CA, during CalNex 2010

    NASA Astrophysics Data System (ADS)

    Tsai, J.; Pikelnaya, O.; Hurlock, S. C.; Wong, K.; Cheung, R.; Haman, C. L.; Lefer, B. L.; Stutz, J.

    2010-12-01

    Nocturnal chemistry, through the conversion and removal of air pollutants, plays an important role in determining the initial condition for photochemistry during the following day. In the stable nocturnal boundary layer (NBL) the interplay between suppressed vertical mixing and surface emissions of NOx and VOCs can result in pronounced vertical trace gas profiles. The resulting altitude dependence of nocturnal chemistry makes the interpretation of ground observations challenging. In particular, the quantification of the nocturnal loss of NOx, due to NO3 and N2O5 chemistry, requires observations throughout the entire vertical extent of the NBL. The formation of daytime radical precursors, such as HONO, is also altitude dependent. An accurate assessment of their impact on daytime chemistry requires measurements of their profiles during the night and morning. Here we present observations from the CalNex-LA experiment, which took place from May 15 to June 15, 2010 on the east side of the Los Angeles Basin, CA. A Long-Path Differential Optical Absorption Spectrometer (LP-DOAS) was set up on the roof of the Millikan library (265 m asl, 35m agl) on the campus of the California Institute of Technology. Four retroreflector arrays were mounted about 5 -7 km North-East of the instrument at 310m, 353m, 487m and 788 m asl. The vertical profiles of NO3, HONO, NO2, O3, HCHO, and SO2 were retrieved at altitude intervals of 35-78m, 78-121m, 121-255m and 255-556m above the ground. During many nights vertical gradients were observed, with elevated NO2 and HONO concentrations near the surface and larger ozone and NO3 concentrations aloft. Simultaneous ceilometer observations of the NBL structure show the impact of meteorology on the vertical trace gas distributions. We will discuss the consequences of trace gases gradients on the nocturnal NOx budget.

  14. Short-term nitrogen additions can shift a coastal wetland from a sink to a source of N2O

    USGS Publications Warehouse

    Moseman-Valtierra, S.; Gonzalez, R.; Kroeger, K.D.; Tang, J.; Chao, W.C.; Crusius, J.; Bratton, J.; Green, A.; Shelton, J.

    2011-01-01

    Coastal salt marshes sequester carbon at high rates relative to other ecosystems and emit relatively little methane particularly compared to freshwater wetlands. However, fluxes of all major greenhouse gases (N2O, CH4, and CO2) need to be quantified for accurate assessment of the climatic roles of these ecosystems. Anthropogenic nitrogen inputs (via run-off, atmospheric deposition, and wastewater) impact coastal marshes. To test the hypothesis that a pulse of nitrogen loading may increase greenhouse gas emissions from salt marsh sediments, we compared N2O, CH4 and respiratory CO2 fluxes from nitrate-enriched plots in a Spartina patens marsh (receiving single additions of NaNO3 equivalent to 1.4 g N m-2) to those from control plots (receiving only artificial seawater solutions) in three short-term experiments (July 2009, April 2010, and June 2010). In July 2009, we also compared N2O and CH4 fluxes in both opaque and transparent chambers to test the influence of light on gas flux measurements. Background fluxes of N2O in July 2009 averaged -33 ??mol N2O m-2 day-1. However, within 1 h of nutrient additions, N2O fluxes were significantly greater in plots receiving nitrate additions relative to controls in July 2009. Respiratory rates and CH4 fluxes were not significantly affected. N2O fluxes were significantly higher in dark than in transparent chambers, averaging 108 and 42 ??mol N2O m-2 day-1 respectively. After 2 days, when nutrient concentrations returned to background levels, none of the greenhouse gas fluxes differed from controls. In April 2010, N2O and CH4 fluxes were not significantly affected by nitrate, possibly due to higher nitrogen demands by growing S. patens plants, but in June 2010 trends of higher N2O fluxes were again found among nitrate-enriched plots, indicating that responses to nutrient pulses may be strongest during the summer. In terms of carbon equivalents, the highest average N2O and CH4 fluxes observed, exceeded half the magnitude of typical

  15. Short-term nitrogen additions can shift a coastal wetland from a sink to a source of N2O

    USGS Publications Warehouse

    Moseman-Valtierra, Serena; Gonzalez, Rosalinda; Kroeger, Kevin D.; Tang, Jianwu; Chao, Wei Chun; Crusius, John; Bratton, John; Green, Adrian; Shelton, James

    2011-01-01

    Coastal salt marshes sequester carbon at high rates relative to other ecosystems and emit relatively little methane particularly compared to freshwater wetlands. However, fluxes of all major greenhouse gases (N2O, CH4, and CO2) need to be quantified for accurate assessment of the climatic roles of these ecosystems. Anthropogenic nitrogen inputs (via run-off, atmospheric deposition, and wastewater) impact coastal marshes. To test the hypothesis that a pulse of nitrogen loading may increase greenhouse gas emissions from salt marsh sediments, we compared N2O, CH4 and respiratory CO2fluxes from nitrate-enriched plots in a Spartina patens marsh (receiving single additions of NaNO3 equivalent to 1.4 g N m−2) to those from control plots (receiving only artificial seawater solutions) in three short-term experiments (July 2009, April 2010, and June 2010). In July 2009, we also compared N2O and CH4 fluxes in both opaque and transparent chambers to test the influence of light on gas flux measurements. Background fluxes of N2O in July 2009 averaged −33 μmol N2O m−2 day−1. However, within 1 h of nutrient additions, N2O fluxes were significantly greater in plots receiving nitrate additions relative to controls in July 2009. Respiratory rates and CH4 fluxes were not significantly affected. N2O fluxes were significantly higher in dark than in transparent chambers, averaging 108 and 42 μmol N2O m−2 day−1 respectively. After 2 days, when nutrient concentrations returned to background levels, none of the greenhouse gas fluxes differed from controls. In April 2010, N2O and CH4 fluxes were not significantly affected by nitrate, possibly due to higher nitrogen demands by growing S. patens plants, but in June 2010 trends of higher N2O fluxes were again found among nitrate-enriched plots, indicating that responses to nutrient pulses may be strongest during the summer. In terms of carbon equivalents, the highest average N2O and CH4 fluxes observed, exceeded half

  16. Short-term nitrogen additions can shift a coastal wetland from a sink to a source of N 2O

    NASA Astrophysics Data System (ADS)

    Moseman-Valtierra, Serena; Gonzalez, Rosalinda; Kroeger, Kevin D.; Tang, Jianwu; Chao, Wei Chun; Crusius, John; Bratton, John; Green, Adrian; Shelton, James

    2011-08-01

    Coastal salt marshes sequester carbon at high rates relative to other ecosystems and emit relatively little methane particularly compared to freshwater wetlands. However, fluxes of all major greenhouse gases (N 2O, CH 4, and CO 2) need to be quantified for accurate assessment of the climatic roles of these ecosystems. Anthropogenic nitrogen inputs (via run-off, atmospheric deposition, and wastewater) impact coastal marshes. To test the hypothesis that a pulse of nitrogen loading may increase greenhouse gas emissions from salt marsh sediments, we compared N 2O, CH 4 and respiratory CO 2 fluxes from nitrate-enriched plots in a Spartina patens marsh (receiving single additions of NaNO 3 equivalent to 1.4 g N m -2) to those from control plots (receiving only artificial seawater solutions) in three short-term experiments (July 2009, April 2010, and June 2010). In July 2009, we also compared N 2O and CH 4 fluxes in both opaque and transparent chambers to test the influence of light on gas flux measurements. Background fluxes of N 2O in July 2009 averaged -33 μmol N 2O m -2 day -1. However, within 1 h of nutrient additions, N 2O fluxes were significantly greater in plots receiving nitrate additions relative to controls in July 2009. Respiratory rates and CH 4 fluxes were not significantly affected. N 2O fluxes were significantly higher in dark than in transparent chambers, averaging 108 and 42 μmol N 2O m -2 day -1 respectively. After 2 days, when nutrient concentrations returned to background levels, none of the greenhouse gas fluxes differed from controls. In April 2010, N 2O and CH 4 fluxes were not significantly affected by nitrate, possibly due to higher nitrogen demands by growing S. patens plants, but in June 2010 trends of higher N 2O fluxes were again found among nitrate-enriched plots, indicating that responses to nutrient pulses may be strongest during the summer. In terms of carbon equivalents, the highest average N 2O and CH 4 fluxes observed, exceeded half

  17. Populations of Dalapon-decomposing Bacteria in Soil as Influenced by Additions of Dalapon or Other Carbon Sources

    PubMed Central

    Burge, Wylie D.

    1969-01-01

    The numbers of bacteria capable of decomposing the herbicide dalapon were determined for five soils by the most-probable-number method. Before treatment of the soils with dalapon, the numbers varied from 1,000 to 10,000 cells per g of soil. Incubation of the soils with dalapon resulted in large increases (100-fold) in two of three soils in which dalapon was decomposed rapidly. Lack of increase in numbers in spite of rapid decomposition in the other soil probably indicated breakdown by a chemical process or decomposition by fungi. In the remaining two soils, in which decomposition was slow in one and did not occur in the other, the initial numbers were at the low end of the range and the increase was small on incubation with dalapon. Addition of ground alfalfa or ground corn plant material to a soil did not result in significant increases in the numbers of dalapon-decomposing bacteria, either during or after decomposition of the plant material. Glucose depressed the rate of breakdown of dalapon in the soil and increased dalapon-decomposing Bacillus species rather than Arthrobacter and Agrobacterium species, which were found to increase on incubation with dalapon itself. The most-probable-number method appears to be a valuable tool for pesticide-ecology studies. PMID:5772393

  18. Complexes of HNO3 and NO3 - with NO2 and N2O4, and their potential role in atmospheric HONO formation.

    PubMed

    Kamboures, Michael A; Raff, Jonathan D; Miller, Yifat; Phillips, Leon F; Finlayson-Pitts, Barbara J; Gerber, R Benny

    2008-10-21

    Calculations were performed to determine the structures, energetics, and spectroscopy of the atmospherically relevant complexes (HNO(3)).(NO(2)), (HNO(3)).(N(2)O(4)), (NO(3)(-)).(NO(2)), and (NO(3)(-)).(N(2)O(4)). The binding energies indicate that three of the four complexes are quite stable, with the most stable (NO(3)(-)).(N(2)O(4)) possessing binding energy of almost -14 kcal mol(-1). Vibrational frequencies were calculated for use in detecting the complexes by infrared and Raman spectroscopy. An ATR-FTIR experiment showed features at 1632 and 1602 cm(-1) that are attributed to NO(2) complexed to NO(3)(-) and HNO(3), respectively. The electronic states of (HNO(3)).(N(2)O(4)) and (NO(3)(-)).(N(2)O(4)) were investigated using an excited state method and it was determined that both complexes possess one low-lying excited state that is accessible through absorption of visible radiation. Evidence for the existence of (NO(3)(-)).(N(2)O(4)) was obtained from UV/vis absorption spectra of N(2)O(4) in concentrated HNO(3), which show a band at 320 nm that is blue shifted by 20 nm relative to what is observed for N(2)O(4) dissolved in organic solvents. Finally, hydrogen transfer reactions within the (HNO(3)).(NO(2)) and (HNO(3)).(N(2)O(4)) complexes leading to the formation of HONO, were investigated. In both systems the calculated potential profiles rule out a thermal mechanism, but indicate the reaction could take place following the absorption of visible radiation. We propose that these complexes are potentially important in the thermal and photochemical production of HONO observed in previous laboratory and field studies.

  19. Complexes of HNO₃ and NO₃¯ with NO₂ and N₂O₄, and their potential role in atmospheric HONO formation

    SciTech Connect

    Kamboures, Michael A.; Raff, Jonathan D.; Miller, Y.; Phillips, Leon F.; Finlayson-Pitts, Barbara J.; Gerber, Robert B.

    2008-08-11

    Calculations were performed to determine the structures, energetics, and spectroscopy of the atmospherically relevant complexes (HNO₃)•(NO₂), (HNO₃)•(N₂O₄), (NO₃¯)•(NO₂), and (NO₃¯)•(N₂O₄). The binding energies indicate that three of the four complexes are quite stable, with the most stable (NO₃¯)•(N₂O₄) possessing binding energy of almost -14 kcal mol¯¹. Vibrational frequencies were calculated for use in detecting the complexes by infrared and Raman spectroscopy. An ATR-FTIR experiment showed features at 1632 and 1602 cm¯¹ that are attributed to NO₂ complexed to NO₃¯ and HNO₃, respectively. The electronic states of (HNO₃)•(N₂O₄) and (NO₃¯)•( N₂O₄) were investigated using an excited state method and it was determined that both complexes possess one low-lying excited state that is accessible through absorption of visible radiation. Evidence for the existence of (NO₃¯)•( N₂O₄) was obtained from UV/vis absorption spectra of N₂O₄ in concentrated HNO₃, which show a band at 320 nm that is blue shifted by 20 nm relative to what is observed for N₂O₄ dissolved in organic solvents. Finally, hydrogen transfer reactions within the (HNO₃)•(NO₂) and (HNO₃)•( N₂O₄) complexes leading to the formation of HONO, were investigated. In both systems the calculated potential profiles rule out a thermal mechanism, but indicate the reaction could take place following the absorption of visible radiation. We propose that these complexes are potentially important in the thermal and photochemical production of HONO observed in previous laboratory and field studies.

  20. Determination of additivity of apparent and standardized ileal digestibility of amino acids in diets containing multiple protein sources fed to growing pigs.

    PubMed

    Xue, P C; Ragland, D; Adeola, O

    2014-09-01

    An experiment was conducted in growing pigs to investigate the additivity of apparent ileal digestibility (AID) or standardized ileal digestibility (SID) of CP and AA in mixed diets containing multiple protein sources. Using the determined AID or SID for CP and AA in corn, soybean meal (SBM), corn distillers' dried grains with solubles (DDGS), or canola meal (CM), the AID or SID for 4 mixed diets based on corn-SBM, corn-SBM-DDGS, corn-SBM-CM, or corn-SBM-DDGS-CM were predicted and compared with determined AID or SID, respectively. Eighteen growing pigs (initial BW = 61.3 ± 5.5 kg) were surgically fitted with T-cannulas and assigned to a duplicated 9 × 4 incomplete Latin square design with 9 diets and 4 periods. The 9 experimental diets consisted of a nitrogen-free diet (NFD) to estimate basal ileal endogenous loss (BEL) of AA, 4 semipurified diets to determine the AID and SID of CP and AA in the 4 ingredients, and 4 mixed diets to test the additivity of AID and SID. Chromic oxide was added as an indigestible marker. Pigs were fed 1 of the 9 diets during each 7-d period, and ileal digesta were collected on d 6 and 7, from 0800 to 1800 h. The analyzed AA levels for the mixed diets were close to the calculated values based on the AA composition of each ingredient. The results revealed that the predicted SID were consistent with determined values, except for Leu, Thr, Asp, Cys, Pro, and Ser in the corn-SBM diet and Met and Cys in the corn-SBM-DDGS diet. The determined AID for total AA and Arg, His, Trp, Gly, and Pro in the corn-SBM diet were greater (P < 0.05) than predicted. For the corn-SBM-DDGS diet, the determined AID were greater (P < 0.05) than predicted AID for CP, total AA, and all AA except for Arg, Leu, and Pro. In the corn-SBM-CM diet, the determined AID were greater (P < 0.05) than predicted AID for Arg, Cys, and Gly. When compared with determined values, predicted AID in the corn-SBM-DDGS-CM diet were lower (P < 0.05) for total AA and Arg, Met, Cys, and

  1. Increasing fermentation efficiency at high sugar concentrations by supplementing an additional source of nitrogen during the exponential phase of the tequila fermentation process.

    PubMed

    Arrizon, Javier; Gschaedler, Anne

    2002-11-01

    In the tequila industry, fermentation is traditionally achieved at sugar concentrations ranging from 50 to 100 g x L(-1). In this work, the behaviour of the Saccharomyces cerevisiae yeast (isolated from the juices of the Agave tequilana Weber blue variety) during the agave juice fermentation is compared at different sugar concentrations to determine if it is feasible for the industry to run fermentation at higher sugar concentrations. Fermentation efficiency is shown to be higher (above 90%) at a high concentration of initial sugar (170 g x L(-1)) when an additional source of nitrogen (a mixture of amino acids and ammonium sulphate, different than a grape must nitrogen composition) is added during the exponential growth phase.

  2. Optimization of anaerobically digested distillery molasses spent wash decolorization using soil as inoculum in the absence of additional carbon and nitrogen source.

    PubMed

    Adikane, H V; Dange, M N; Selvakumari, K

    2006-11-01

    The aim of this study was to achieve maximum decolorization of molasses spent wash (MSW) in absence of any additional carbon or nitrogen source using soil as inoculum. Soil samples were collected from the MSW disposal site. Colored soil samples exhibited higher pH, sugar and protein as compare to less colored samples. A decolorization of 69% was obtained using 10% (w/v) soil and 12.5% (v/v) MSW after 7 days incubation. Optimized parameters including days--6 days, pH--6, MSW--12.5% and soil concentration--40%, were obtained for maximum decolorization. A decolorization of 81% was achieved using 10% soil and 12.5% MSW after 18 days incubation in absence of any media supplement. Nearly 12% reduction in decolorization activity of the soil sample was observed over a period of 12 months when stored at 6 degrees C. It could be concluded that the decolorization of MSW might be achieved using soil as inoculum without addition of chemical amendments.

  3. Dual-source dual-energy CT with additional tin filtration: Dose and image quality evaluation in phantoms and in-vivo

    PubMed Central

    Primak, Andrew N.; Giraldo, Juan Carlos Ramirez; Eusemann, Christian D.; Schmidt, Bernhard; Kantor, B.; Fletcher, Joel G.; McCollough, Cynthia H.

    2010-01-01

    Purpose To investigate the effect on radiation dose and image quality of the use of additional spectral filtration for dual-energy CT (DECT) imaging using dual-source CT (DSCT). Materials and Methods A commercial DSCT scanner was modified by adding tin filtration to the high-kV tube, and radiation output and noise measured in water phantoms. Dose values for equivalent image noise were compared among DE-modes with and without tin filtration and single-energy (SE) mode. To evaluate DECT material discrimination, the material-specific DEratio for calcium and iodine were determined using images of anthropomorphic phantoms. Data were additionally acquired in 38 and 87 kg pigs, and noise for the linearly mixed and virtual non-contrast (VNC) images compared between DE-modes. Finally, abdominal DECT images from two patients of similar sizes undergoing clinically-indicated CT were compared. Results Adding tin filtration to the high-kV tube improved the DE contrast between iodine and calcium as much as 290%. Pig data showed that the tin filtration had no effect on noise in the DECT mixed images, but decreased noise by as much as 30% in the VNC images. Patient VNC-images acquired using 100/140 kV with added tin filtration had improved image quality compared to those generated with 80/140 kV without tin filtration. Conclusion Tin filtration of the high-kV tube of a DSCT scanner increases the ability of DECT to discriminate between calcium and iodine, without increasing dose relative to SECT. Furthermore, use of 100/140 kV tube potentials allows improved DECT imaging of large patients. PMID:20966323

  4. [Underreporting of tuberculosis in the Information System on Notifiable Diseases (SINAN): primary default and case detection from additional data sources using probabilistic record linkage].

    PubMed

    Pinheiro, Rejane Sobrino; Andrade, Vanusa de Lemos; Oliveira, Gisele Pinto de

    2012-08-01

    This study aimed to analyze underreporting of tuberculosis (TB) cases in the Information System on Notifiable Diseases (SINAN), based on the following data sources: Mortality Information System (SIM), Registry and Follow-up Book for TB Case Treatment (LPATB), and Laboratory Registry Book (LRLAB). Probabilistic record linkage was used between the SIM (2007-2008) and SINAN (2002-2008). A search was conducted in LPATB and LRLAB (2007-2008) for cases not recorded in SINAN. There were 125 deaths, of which 44.8% were not recorded in SINAN. In LPATB, 58 cases (5.1%) were in treatment and were not reported in SINAN. LRLAB showed 32 smear-positive cases not reported to SINAN and without treatment, representing primary default. Addition of the retrieved cases, led to a 14.6% increase in the incidence rate in 2007 and 11.6% in 2008. Underreporting of deaths from or with TB in the Mortality Information System and primary default revealed difficulties in access to adequate and timely treatment, calling for rethinking of strategies to detect cases for timely treatment.

  5. Effect of high-pressure/temperature (HP/T) treatments of in-package food on additive migration from conventional and bio-sourced materials.

    PubMed

    Mauricio-Iglesias, M; Jansana, S; Peyron, S; Gontard, N; Guillard, V

    2010-01-01

    Migration was assessed during and after two high-pressure/temperature (HP/T) treatments intended for a pasteurization (800 MPa for 5 min, from 20 to 40 degrees C) and a sterilization treatment (800 MPa for 5 min, from 90 to 115 degrees C) and were compared with conventional pasteurization and sterilization, respectively. The specific migration of actual packaging additives used as antioxidants and ultraviolet light absorbers (Irganox 1076, Uvitex OB) was investigated in a number of food-packaging systems combining one synthetic common packaging (LLDPE) and a bio-sourced one (PLA) in contact with the four food-simulating liquids defined by European Commission regulations. After standard HP/T processing, migration kinetics was followed during the service life of the packaging material using Fourier transform infrared spectrometer (FTIR) spectroscopy. LLDPE withstood the high-pressure sterilization, whereas it melted during the conventional sterilization. No difference was observed on migration from LLDPE for both treatments. In the case of PLA, migration of Uvitex OB was very low or not detectable for all the cases studied.

  6. The contribution of soil biogenic NO and HONO emissions from a managed hyperarid ecosystem to the regional NOx emissions during growing season

    NASA Astrophysics Data System (ADS)

    Mamtimin, Buhalqem; Meixner, Franz X.; Behrendt, Thomas; Badawy, Moawad; Wagner, Thomas

    2016-08-01

    A study was carried out to understand the contributions of soil biogenic NO emissions from managed (fertilized and irrigated) hyperarid ecosystems in NW China to the regional NOx emissions during the growing season. Soil biogenic net potential NO fluxes were quantified by laboratory incubation of soil samples from the three dominating ecosystems (desert, cotton, and grape fields). Regional biogenic NO emissions were calculated bottom-up hourly for the entire growing season (April-September 2010) by considering corresponding land use, hourly data of soil temperature, gravimetric soil moisture, and fertilizer enhancement factors. The regional HONO emissions were estimated using the ratio of the optimum condition ((FN,opt(HONO) to FN,opt (NO)). Regional anthropogenic NOx emissions were calculated bottom-up from annual statistical data provided by regional and local government bureaus which have been downscaled to monthly value. Regional top-down emission estimates of NOx were derived on the monthly basis from satellite observations (OMI) of tropospheric vertical NO2 column densities and prescribed values of the tropospheric NOx lifetime. In order to compare the top-down and bottom-up emission estimates, all emission estimates were expressed in terms of mass of atomic nitrogen. Consequently, monthly top-down NOx emissions (total) were compared with monthly bottom-up NOx emissions (biogenic + anthropogenic) for the time of the satellite overpass (around 13:00 LT) with the consideration of the diurnal cycle of bottom-up estimates. Annual variation in total Tohsun Oasis NOx emissions is characterized by a strong peak in winter (December-February) and a secondary peak in summer (June-August). During summer, soil biogenic emissions were from equal to double that of related anthropogenic emissions, and grape soils were the main contributor to soil biogenic emissions, followed by cotton soils, while emissions from the desert were negligible. The top-down and bottom

  7. Estimating PM2.5 Concentrations in Xi'an City Using a Generalized Additive Model with Multi-Source Monitoring Data

    PubMed Central

    Song, Yong-Ze; Yang, Hong-Lei; Peng, Jun-Huan; Song, Yi-Rong; Sun, Qian; Li, Yuan

    2015-01-01

    Particulate matter with an aerodynamic diameter <2.5 μm (PM2.5) represents a severe environmental problem and is of negative impact on human health. Xi'an City, with a population of 6.5 million, is among the highest concentrations of PM2.5 in China. In 2013, in total, there were 191 days in Xi’an City on which PM2.5 concentrations were greater than 100 μg/m3. Recently, a few studies have explored the potential causes of high PM2.5 concentration using remote sensing data such as the MODIS aerosol optical thickness (AOT) product. Linear regression is a commonly used method to find statistical relationships among PM2.5 concentrations and other pollutants, including CO, NO2, SO2, and O3, which can be indicative of emission sources. The relationships of these variables, however, are usually complicated and non-linear. Therefore, a generalized additive model (GAM) is used to estimate the statistical relationships between potential variables and PM2.5 concentrations. This model contains linear functions of SO2 and CO, univariate smoothing non-linear functions of NO2, O3, AOT and temperature, and bivariate smoothing non-linear functions of location and wind variables. The model can explain 69.50% of PM2.5 concentrations, with R2 = 0.691, which improves the result of a stepwise linear regression (R2 = 0.582) by 18.73%. The two most significant variables, CO concentration and AOT, represent 20.65% and 19.54% of the deviance, respectively, while the three other gas-phase concentrations, SO2, NO2, and O3 account for 10.88% of the total deviance. These results show that in Xi'an City, the traffic and other industrial emissions are the primary source of PM2.5. Temperature, location, and wind variables also non-linearly related with PM2.5. PMID:26540446

  8. Estimating PM2.5 Concentrations in Xi'an City Using a Generalized Additive Model with Multi-Source Monitoring Data.

    PubMed

    Song, Yong-Ze; Yang, Hong-Lei; Peng, Jun-Huan; Song, Yi-Rong; Sun, Qian; Li, Yuan

    2015-01-01

    Particulate matter with an aerodynamic diameter <2.5 μm (PM2.5) represents a severe environmental problem and is of negative impact on human health. Xi'an City, with a population of 6.5 million, is among the highest concentrations of PM2.5 in China. In 2013, in total, there were 191 days in Xi'an City on which PM2.5 concentrations were greater than 100 μg/m3. Recently, a few studies have explored the potential causes of high PM2.5 concentration using remote sensing data such as the MODIS aerosol optical thickness (AOT) product. Linear regression is a commonly used method to find statistical relationships among PM2.5 concentrations and other pollutants, including CO, NO2, SO2, and O3, which can be indicative of emission sources. The relationships of these variables, however, are usually complicated and non-linear. Therefore, a generalized additive model (GAM) is used to estimate the statistical relationships between potential variables and PM2.5 concentrations. This model contains linear functions of SO2 and CO, univariate smoothing non-linear functions of NO2, O3, AOT and temperature, and bivariate smoothing non-linear functions of location and wind variables. The model can explain 69.50% of PM2.5 concentrations, with R2 = 0.691, which improves the result of a stepwise linear regression (R2 = 0.582) by 18.73%. The two most significant variables, CO concentration and AOT, represent 20.65% and 19.54% of the deviance, respectively, while the three other gas-phase concentrations, SO2, NO2, and O3 account for 10.88% of the total deviance. These results show that in Xi'an City, the traffic and other industrial emissions are the primary source of PM2.5. Temperature, location, and wind variables also non-linearly related with PM2.5.

  9. Inductively coupled plasma spectrometry: Noise characteristics of aerosols, application of generalized standard additions method, and Mach disk as an emission source

    SciTech Connect

    Luan, Shen

    1995-10-06

    This dissertation is focused on three problem areas in the performance of inductively coupled plasma (ICP) source. The noise characteristics of aerosols produced by ICP nebulizers are investigated. A laser beam is scattered by aerosol and detected by a photomultiplier tube and the noise amplitude spectrum of the scattered radiation is measured by a spectrum analyzer. Discrete frequency noise in the aerosol generated by a Meinhard nebulizer or a direct injection nebulizer is primarily caused by pulsation in the liquid flow from the pump. A Scott-type spray chamber suppresses white noise, while a conical, straight-pass spray chamber enhances white noise, relative to the noise seen from the primary aerosol. Simultaneous correction for both spectral interferences and matrix effects in ICP atomic emission spectrometry (AES) can be accomplished by using the generalized standard additions method (GSAM). Results obtained with the application of the GSAM to the Perkin-Elmer Optima 3000 ICP atomic emission spectrometer are presented. The echelle-based polychromator with segmented-array charge-coupled device detectors enables the direct, visual examination of the overlapping lines Cd (1) 228.802 nm and As (1) 228.812 nm. The slit translation capability allows a large number of data points to be sampled, therefore, the advantage of noise averaging is gained. An ICP is extracted into a small quartz vacuum chamber through a sampling orifice in a water-cooled copper plate. Optical emission from the Mach disk region is measured with a new type of echelle spectrometer equipped with two segmented-array charge-coupled-device detectors, with an effort to improve the detection limits for simultaneous multielement analysis by ICP-AES.

  10. The effectiveness of power-generating complexes constructed on the basis of nuclear power plants combined with additional sources of energy determined taking risk factors into account

    NASA Astrophysics Data System (ADS)

    Aminov, R. Z.; Khrustalev, V. A.; Portyankin, A. V.

    2015-02-01

    The effectiveness of combining nuclear power plants equipped with water-cooled water-moderated power-generating reactors (VVER) with other sources of energy within unified power-generating complexes is analyzed. The use of such power-generating complexes makes it possible to achieve the necessary load pickup capability and flexibility in performing the mandatory selective primary and emergency control of load, as well as participation in passing the night minimums of electric load curves while retaining high values of the capacity utilization factor of the entire power-generating complex at higher levels of the steam-turbine part efficiency. Versions involving combined use of nuclear power plants with hydrogen toppings and gas turbine units for generating electricity are considered. In view of the fact that hydrogen is an unsafe energy carrier, the use of which introduces additional elements of risk, a procedure for evaluating these risks under different conditions of implementing the fuel-and-hydrogen cycle at nuclear power plants is proposed. Risk accounting technique with the use of statistical data is considered, including the characteristics of hydrogen and gas pipelines, and the process pipelines equipment tightness loss occurrence rate. The expected intensities of fires and explosions at nuclear power plants fitted with hydrogen toppings and gas turbine units are calculated. In estimating the damage inflicted by events (fires and explosions) occurred in nuclear power plant turbine buildings, the US statistical data were used. Conservative scenarios of fires and explosions of hydrogen-air mixtures in nuclear power plant turbine buildings are presented. Results from calculations of the introduced annual risk to the attained net annual profit ratio in commensurable versions are given. This ratio can be used in selecting projects characterized by the most technically attainable and socially acceptable safety.

  11. The Multi-allelic Genetic Architecture of a Variance-Heterogeneity Locus for Molybdenum Concentration in Leaves Acts as a Source of Unexplained Additive Genetic Variance

    PubMed Central

    Forsberg, Simon K. G.; Andreatta, Matthew E.; Huang, Xin-Yuan; Danku, John; Salt, David E.; Carlborg, Örjan

    2015-01-01

    Genome-wide association (GWA) analyses have generally been used to detect individual loci contributing to the phenotypic diversity in a population by the effects of these loci on the trait mean. More rarely, loci have also been detected based on variance differences between genotypes. Several hypotheses have been proposed to explain the possible genetic mechanisms leading to such variance signals. However, little is known about what causes these signals, or whether this genetic variance-heterogeneity reflects mechanisms of importance in natural populations. Previously, we identified a variance-heterogeneity GWA (vGWA) signal for leaf molybdenum concentrations in Arabidopsis thaliana. Here, fine-mapping of this association reveals that the vGWA emerges from the effects of three independent genetic polymorphisms that all are in strong LD with the markers displaying the genetic variance-heterogeneity. By revealing the genetic architecture underlying this vGWA signal, we uncovered the molecular source of a significant amount of hidden additive genetic variation or “missing heritability”. Two of the three polymorphisms underlying the genetic variance-heterogeneity are promoter variants for Molybdate transporter 1 (MOT1), and the third a variant located ~25 kb downstream of this gene. A fourth independent association was also detected ~600 kb upstream of MOT1. Use of a T-DNA knockout allele highlights Copper Transporter 6; COPT6 (AT2G26975) as a strong candidate gene for this association. Our results show that an extended LD across a complex locus including multiple functional alleles can lead to a variance-heterogeneity between genotypes in natural populations. Further, they provide novel insights into the genetic regulation of ion homeostasis in A. thaliana, and empirically confirm that variance-heterogeneity based GWA methods are a valuable tool to detect novel associations of biological importance in natural populations. PMID:26599497

  12. Vertical columns of NO2, HONO, HCHO, CHOCHO and aerosol extinction: diurnal and seasonal variations in context of CalNex and CARES

    NASA Astrophysics Data System (ADS)

    Ortega, I.; Coburn, S.; Oetjen, H.; Sinreich, R.; Thalman, R. M.; Waxman, E.; Volkamer, R.

    2011-12-01

    We present results from two ground-based University of Colorado Multi Axis Differential Optical Absorption Spectroscopy (CU-MAX-DOAS) instruments that were deployed during the CALNEX and CARES 2010 field campaigns. Ground based CU-MAX-DOAS measurements were carried out through Dec 2010, and measured vertical column abundances of nitrogen dioxide (NO2), nitrous acid (HONO), formaldehyde (HCHO), glyoxal (CHOCHO), and aerosol extinction, which is determined indirectly from observing the oxygen dimers (O4). The measurements were acquired on the top of Millikan library at Caltech, Pasadena, CA, at the Fontana Arrows site located 60 Km east of Caltech, and for a limited period also downwind of Sacramento at T1 site during CARES. In the South Coast Air Basin, the MAX-DOAS instruments at both sites collected an extended time series of use to test satellites, and atmospheric chemistry models. We determine the state of the planetary boundary layer by comparing the columns observations with in-situ sensors, and place the CALNEX and CARES measurements intensive into seasonal context.

  13. Oxidative capacity of the Mexico City atmosphere - Part 1: A radical source perspective

    NASA Astrophysics Data System (ADS)

    Volkamer, R.; Sheehy, P.; Molina, L. T.; Molina, M. J.

    2010-07-01

    A detailed analysis of OH, HO2 and RO2 radical sources is presented for the near field photochemical regime inside the Mexico City Metropolitan Area (MCMA). During spring of 2003 (MCMA-2003 field campaign) an extensive set of measurements was collected to quantify time-resolved ROx (sum of OH, HO2, RO2) radical production rates from day- and nighttime radical sources. The Master Chemical Mechanism (MCMv3.1) was constrained by measurements of (1) concentration time-profiles of photosensitive radical precursors, i.e., nitrous acid (HONO), formaldehyde (HCHO), ozone (O3), glyoxal (CHOCHO), and other oxygenated volatile organic compounds (OVOCs); (2) respective photolysis-frequencies (J-values); (3) concentration time-profiles of alkanes, alkenes, and aromatic VOCs (103 compound are treated) and oxidants, i.e., OH- and NO3 radicals, O3; and (4) NO, NO2, meteorological and other parameters. The ROx production rate was calculated directly from these observations; the MCM was used to estimate further ROx production from unconstrained sources, and express overall ROx production as OH-equivalents (i.e., taking into account the propagation efficiencies of RO2 and HO2 radicals into OH radicals). Daytime radical production is found to be about 10-25 times higher than at night; it does not track the abundance of sunlight. 12-h average daytime contributions of individual sources are: Oxygenated VOC other than HCHO about 33%; HCHO and O3 photolysis each about 20%; O3/alkene reactions and HONO photolysis each about 12%, other sources <3%. Nitryl chloride photolysis could potentially contribute ~15% additional radicals, while NO2* + water makes - if any - a very small contribution (~2%). The peak radical production of ~7.5 107 molec cm-3 s-1 is found already at 10:00 a.m., i.e., more than 2.5 h before solar noon. O3/alkene reactions are indirectly responsible for ~33% of these radicals. Our measurements and analysis comprise a database that enables testing of the representation of

  14. Food additives

    PubMed Central

    Spencer, Michael

    1974-01-01

    Food additives are discussed from the food technology point of view. The reasons for their use are summarized: (1) to protect food from chemical and microbiological attack; (2) to even out seasonal supplies; (3) to improve their eating quality; (4) to improve their nutritional value. The various types of food additives are considered, e.g. colours, flavours, emulsifiers, bread and flour additives, preservatives, and nutritional additives. The paper concludes with consideration of those circumstances in which the use of additives is (a) justified and (b) unjustified. PMID:4467857

  15. Breeding Pierce’s disease resistant table and raisin grapes and the development of markers for additional sources of resistance 2008

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Twenty-two seedless x seedless crosses to develop additional BC2 and BC3 V. arizonica and BC1 SEUS BD5-117 families were made in 2008. Powdery mildew resistance was included in five of these crosses. These crosses produced 5,148 berries, 8,824 ovules and 1,861 embryos. Nine seeded BC1 crosses bas...

  16. Food additives

    MedlinePlus

    ... or natural. Natural food additives include: Herbs or spices to add flavor to foods Vinegar for pickling ... Certain colors improve the appearance of foods. Many spices, as well as natural and man-made flavors, ...

  17. Potential N2O Emissions from the Tanks of Bromeliads Suggest an Additional Source of N2O in the Neotropics.

    PubMed

    Suleiman, Marcel; Brandt, Franziska B; Brenzinger, Kristof; Martinson, Guntars O; Braker, Gesche

    2016-12-06

    We studied the propensity of the tank bromeliad Werauhia gladioliflora to emit the greenhouse gas nitrous oxide (N2O) at current and at increased N deposition levels in the range of predicted future scenarios. Potential production rates and net accumulation of N2O from tank substrate corresponded to N availability. N2O was produced in excess at all N levels due to a low level of N2O reductase activity which agreed well with a low abundance of N2O reducers compared to nitrite reducers. Transcriptional activation, however, indicated that expression of denitrification genes may be enhanced with increasing N supply eventually leading to more efficient N2O turnover with potential for adaptation of denitrifier communities to higher N levels. Our findings indicate that tank bromeliads may constitute a novel source of N2O in Neotropical forest canopies but further studies are required to understand the size and significance of in situ N2O fluxes from tank bromeliads to the environment.

  18. Potential biofuel additive from renewable sources--Kinetic study of formation of butyl acetate by heterogeneously catalyzed transesterification of ethyl acetate with butanol.

    PubMed

    Ali, Sami H; Al-Rashed, Osama; Azeez, Fadhel A; Merchant, Sabiha Q

    2011-11-01

    Butyl acetate holds great potential as a sustainable biofuel additive. Heterogeneously catalyzed transesterification of biobutanol and bioethylacetate can produce butyl acetate. This route is eco-friendly and offers several advantages over the commonly used Fischer Esterification. The Amberlite IR 120- and Amberlyst 15-catalyzed transesterification is studied in a batch reactor over a range of catalyst loading (6-12 wt.%), alcohol to ester feed ratio (1:3 to 3:1), and temperature (303.15-333.15K). A butanol mole fraction of 0.2 in the feed is found to be optimum. Amberlite IR 120 promotes faster kinetics under these conditions. The transesterifications studied are slightly exothermic. The moles of solvent sorbed per gram of catalyst decreases (ethanol>butanol>ethyl acetate>butyl acetate) with decrease in solubility parameter. The dual site models, the Langmuir Hinshelwood and Popken models, are the most successful in correlating the kinetics over Amberlite IR 120 and Amberlyst 15, respectively.

  19. Kilogram-scale production of SnO(2) yolk-shell powders by a spray-drying process using dextrin as carbon source and drying additive.

    PubMed

    Choi, Seung Ho; Kang, Yun Chan

    2014-05-05

    A simple and general method for the large-scale production of yolk-shell powders with various compositions by a spray-drying process is reported. Metal salt/dextrin composite powders with a spherical and dense structure were obtained by spray drying and transformed into yolk-shell powders by simple combustion in air. Dextrin plays a key role in the preparation of precursor powders for fabricating yolk-shell powders by spray drying. Droplets containing metal salts and dextrin show good drying characteristics even in a severe environment of high humidity. Sucrose, glucose, and polyvinylpyrrolidone are widely used as carbon sources in the preparation of metal oxide/carbon composite powders; however, they are not appropriate for large-scale spray-drying processes because of their caramelization properties and adherence to the surface of the spray dryer. SnO2 yolk-shell powders were studied as the first target material in the spray-drying process. Combustion of tin oxalate/dextrin composite powders at 600 °C in air produced single-shelled SnO2 yolk-shell powders with the configuration SnO2 @void@SnO2 . The SnO2 yolk-shell powders prepared by the simple spray-drying process showed superior electrochemical properties, even at high current densities. The discharge capacities of the SnO2 yolk-shell powders at a current density of 2000 mA g(-1) were 645 and 570 mA h g(-1) for the second and 100th cycles, respectively; the corresponding capacity retention measured for the second cycle was 88 %.

  20. Diminution of 2,3,5-triphenyltetrazolium chloride toxicity on Listeria monocytogenes growth by iron source addition to the culture medium.

    PubMed

    Junillon, Thomas; Flandrois, Jean-Pierre

    2014-04-01

    Tetrazolium salts (TTZ) such as 2,3,5-triphenyltetrazolium chloride (TTC) are readily reduced by bacterial populations of various genus. The reduced form of these redox indicators is conspicuously colored allowing a quick and easy detection of growth. The studies are mainly confined to Gram negative bacteria because of an important toxic effect of tetrazolium salts on Gram positive bacteria. Indeed, we observed an important impact of different tetrazolium salts on Listeria monocytogenes growth, curiously limited to an increase in the duration of the lag phase. In this study, we demonstrate that increasing the iron concentration in a medium containing TTC leads to a significant decrease of the lag phase. L. monocytogenes growth was kinetically measured and growth parameters were estimated using the Baranyi model. While lag phase diminution was found to be iron concentration dependent, growth rate was not affected. Addition of iron enables growth of some strains totally inhibited by a 0.4 g/l of TTC and for the other a significant reduction of the latency is observed. The nature of the mechanism resulting in a decrease of the observed lag phase remains unclear. Then, the use of iron supplementation may be proposed to overcome the inhibitory effect of TTC on L. monocytogenes.

  1. Effect of the addition of zero valent iron (Fe(0)) on the batch biological sulphate reduction using grass cellulose as carbon source.

    PubMed

    Mulopo, Jean; Schaefer, L

    2013-12-01

    Mineral mining generates acidic, saline, metal-rich mine waters, often referred to as acid mine drainage (AMD). Treatment of AMD and recovering saleable products during the treatment process are a necessity since water is, especially in South Africa, a scarce commodity. The aim of the study presented here was to investigate the effect of zero valent iron (Fe(0)) on the biological removal of sulphate from AMD in batch reactors. The performance of the reactors was assessed by means of sulphate reduction, chemical oxygen demand (COD), volatile fatty acid (VFA) utilisation and volatile suspended solids (VSS) concentration. To this end, three batch reactors, A, B and C (volume 2.5 L), were operated similarly with the exception of the addition of grass cuttings and iron filings. Reactors A and B received twice as much grass (100 g) as C (50 g). Reactor A received no iron filings to act as a control, while reactors B and C received 50-g iron filings for the experimental duration. The results showed that Fe(0) appears to provide sustained sulphate removal when sufficient grass substrate is available. In reactors A and C, sulphate removal efficiency was higher when the COD concentration was lower due to utilisation. In reactor B, sulphate removal efficiency was accompanied by an accumulation of COD as hydrogen (H2) provided by the Fe(0) was utilised for sulphate reduction. Furthermore, these results showed the potential of Fe(0) to enhance the participation of microorganisms in sulphate reduction.

  2. NGSI student activities in open source information analysis in support of the training program of the U.S. DOE laboratories for the entry into force of the additional protocol

    SciTech Connect

    Sandoval, M Analisa; Uribe, Eva C; Sandoval, Marisa N; Boyer, Brian D; Stevens, Rebecca S

    2009-01-01

    In 2008 a joint team from Los Alamos National Laboratory (LANL) and Brookhaven National Laboratory (BNL) consisting of specialists in training of IAEA inspectors in the use of complementary access activities formulated a training program to prepare the U.S. Doe laboratories for the entry into force of the Additional Protocol. As a major part of the support of the activity, LANL summer interns provided open source information analysis to the LANL-BNL mock inspection team. They were a part of the Next Generation Safeguards Initiative's (NGSI) summer intern program aimed at producing the next generation of safeguards specialists. This paper describes how they used open source information to 'backstop' the LANL-BNL team's effort to construct meaningful Additional Protocol Complementary Access training scenarios for each of the three DOE laboratories, Lawrence Livermore National Laboratory, Idaho National Laboratory, and Oak Ridge National Laboratory.

  3. Discovery of a Plains Caldera Complex and Extinct Lava Lake in Arabia Terra, Mars: Implications for the Discovery of Additional Highland Volcanic Source Regions

    NASA Technical Reports Server (NTRS)

    Bleacher, Jacob; Michalski, Joseph

    2012-01-01

    Several irregularly shaped topographic depressions occur near the dichotomy boundary in northern Arabia Terra, Mars. The geomorphology of these features suggests that they formed by collapse, opposed to meteor impact. At least one depression (approx.55 by 85 km) displays geologic features indicating a complex, multi-stage collapse history. Features within and around the collapse structure indicate volcanic processes. The complex occurs within Hesperian ridged plains of likely volcanic origin and displays no crater rim or evidence for ejecta. Instead the depression consists of a series of circumferential graben and down-dropped blocks which also display upper surfaces similar to ridged plain lavas. Large blocks within the depression are tilted towards the crater center, and display graben that appear to have originally been linked with circumferential graben outside of the complex related to earlier collapse events. A nearly 700 m high mound exists along a graben within the complex that might be a vent. The deepest depression displays two sets of nearly continuous terraces, which we interpret as high-stands of a drained lava lake. These features appear similar to the black ledge described during the Kilauea Iki eruption in 1959. A lacustrine origin for the terraces seems unlikely because of the paucity of channels found in or around the depression that could be linked to aqueous surface processes. In addition, there is no obvious evidence for lacustrine sediments within the basin. Together with the presence of significant faulting that is indicative of collapse we conclude that this crater complex represents a large caldera formed in the Late Noachian to Early Hesperian. Other linear and irregular depressions in the region also might be linked to ancient volcanism. If that hypothesis is correct, it suggests that northern Arabia Terra could contain a large, previously unrecognized highland igneous province. Evacuation of magma via explosive and effusive activity

  4. Potlining Additives

    SciTech Connect

    Rudolf Keller

    2004-08-10

    In this project, a concept to improve the performance of aluminum production cells by introducing potlining additives was examined and tested. Boron oxide was added to cathode blocks, and titanium was dissolved in the metal pool; this resulted in the formation of titanium diboride and caused the molten aluminum to wet the carbonaceous cathode surface. Such wetting reportedly leads to operational improvements and extended cell life. In addition, boron oxide suppresses cyanide formation. This final report presents and discusses the results of this project. Substantial economic benefits for the practical implementation of the technology are projected, especially for modern cells with graphitized blocks. For example, with an energy savings of about 5% and an increase in pot life from 1500 to 2500 days, a cost savings of $ 0.023 per pound of aluminum produced is projected for a 200 kA pot.

  5. Phosphazene additives

    DOEpatents

    Harrup, Mason K; Rollins, Harry W

    2013-11-26

    An additive comprising a phosphazene compound that has at least two reactive functional groups and at least one capping functional group bonded to phosphorus atoms of the phosphazene compound. One of the at least two reactive functional groups is configured to react with cellulose and the other of the at least two reactive functional groups is configured to react with a resin, such as an amine resin of a polycarboxylic acid resin. The at least one capping functional group is selected from the group consisting of a short chain ether group, an alkoxy group, or an aryloxy group. Also disclosed are an additive-resin admixture, a method of treating a wood product, and a wood product.

  6. Combined Flux Chamber and Genomics Approach Links Nitrous Acid Emissions to Ammonia Oxidizing Bacteria and Archaea in Urban and Agricultural Soil.

    PubMed

    Scharko, Nicole K; Schütte, Ursel M E; Berke, Andrew E; Banina, Lauren; Peel, Hannah R; Donaldson, Melissa A; Hemmerich, Chris; White, Jeffrey R; Raff, Jonathan D

    2015-12-01

    Nitrous acid (HONO) is a photochemical source of hydroxyl radical and nitric oxide in the atmosphere that stems from abiotic and biogenic processes, including the activity of ammonia-oxidizing soil microbes. HONO fluxes were measured from agricultural and urban soil in mesocosm studies aimed at characterizing biogenic sources and linking them to indigenous microbial consortia. Fluxes of HONO from agricultural and urban soil were suppressed by addition of a nitrification inhibitor and enhanced by amendment with ammonium (NH4(+)), with peaks at 19 and 8 ng m(-2) s(-1), respectively. In addition, both agricultural and urban soils were observed to convert (15)NH4(+) to HO(15)NO. Genomic surveys of soil samples revealed that 1.5-6% of total expressed 16S rRNA sequences detected belonged to known ammonia oxidizing bacteria and archaea. Peak fluxes of HONO were directly related to the abundance of ammonia-oxidizer sequences, which in turn depended on soil pH. Peak HONO fluxes under fertilized conditions are comparable in magnitude to fluxes reported during field campaigns. The results suggest that biogenic HONO emissions will be important in soil environments that exhibit high nitrification rates (e.g., agricultural soil) although the widespread occurrence of ammonia oxidizers implies that biogenic HONO emissions are also possible in the urban and remote environment.

  7. Liquid chromatography coupled to different atmospheric pressure ionization sources-quadrupole-time-of-flight mass spectrometry and post-column addition of metal salt solutions as a powerful tool for the metabolic profiling of Fusarium oxysporum.

    PubMed

    Cirigliano, Adriana M; Rodriguez, M Alejandra; Gagliano, M Laura; Bertinetti, Brenda V; Godeas, Alicia M; Cabrera, Gabriela M

    2016-03-25

    Fusarium oxysporum L11 is a non-pathogenic soil-borne fungal strain that yielded an extract that showed antifungal activity against phytopathogens. In this study, reversed-phase high-performance liquid chromatography (RP-HPLC) coupled to different atmospheric pressure ionization sources-quadrupole-time-of-flight mass spectrometry (API-QTOF-MS) was applied for the comprehensive profiling of the metabolites from the extract. The employed sources were electrospray (ESI), atmospheric pressure chemical ionization (APCI) and atmospheric pressure photoionization (APPI). Post-column addition of metal solutions of Ca, Cu and Zn(II) was also tested using ESI. A total of 137 compounds were identified or tentatively identified by matching their accurate mass signals, suggested molecular formulae and MS/MS analysis with previously reported data. Some compounds were isolated and identified by NMR. The extract was rich in cyclic peptides like cyclosporins, diketopiperazines and sansalvamides, most of which were new, and are reported here for the first time. The use of post-column addition of metals resulted in a useful strategy for the discrimination of compound classes since specific adducts were observed for the different compound families. This technique also allowed the screening for compounds with metal binding properties. Thus, the applied methodology is a useful choice for the metabolic profiling of extracts and also for the selection of metabolites with potential biological activities related to interactions with metal ions.

  8. Volatile organic compound conversion by ozone, hydroxyl radicals, and nitrate radicals in residential indoor air: Magnitudes and impacts of oxidant sources.

    PubMed

    Waring, Michael S; Wells, J Raymond

    2015-04-01

    Indoor chemistry may be initiated by reactions of ozone (O3), the hydroxyl radical (OH), or the nitrate radical (NO3) with volatile organic compounds (VOC). The principal indoor source of O3 is air exchange, while OH and NO3 formation are considered as primarily from O3 reactions with alkenes and nitrogen dioxide (NO2), respectively. Herein, we used time-averaged models for residences to predict O3, OH, and NO3 concentrations and their impacts on conversion of typical residential VOC profiles, within a Monte Carlo framework that varied inputs probabilistically. We accounted for established oxidant sources, as well as explored the importance of two newly realized indoor sources: (i) the photolysis of nitrous acid (HONO) indoors to generate OH and (ii) the reaction of stabilized Criegee intermediates (SCI) with NO2 to generate NO3. We found total VOC conversion to be dominated by reactions both with O3, which almost solely reacted with d-limonene, and also with OH, which reacted with d-limonene, other terpenes, alcohols, aldehydes, and aromatics. VOC oxidation rates increased with air exchange, outdoor O3, NO2 and d-limonene sources, and indoor photolysis rates; and they decreased with O3 deposition and nitric oxide (NO) sources. Photolysis was a strong OH formation mechanism for high NO, NO2, and HONO settings, but SCI/NO2 reactions weakly generated NO3 except for only a few cases.

  9. Volatile organic compound conversion by ozone, hydroxyl radicals, and nitrate radicals in residential indoor air: Magnitudes and impacts of oxidant sources

    PubMed Central

    Waring, Michael S.; Wells, J. Raymond

    2016-01-01

    Indoor chemistry may be initiated by reactions of ozone (O3), the hydroxyl radical (OH), or the nitrate radical (NO3) with volatile organic compounds (VOC). The principal indoor source of O3 is air exchange, while OH and NO3 formation are considered as primarily from O3 reactions with alkenes and nitrogen dioxide (NO2), respectively. Herein, we used time-averaged models for residences to predict O3, OH, and NO3 concentrations and their impacts on conversion of typical residential VOC profiles, within a Monte Carlo framework that varied inputs probabilistically. We accounted for established oxidant sources, as well as explored the importance of two newly realized indoor sources: (i) the photolysis of nitrous acid (HONO) indoors to generate OH and (ii) the reaction of stabilized Criegee intermediates (SCI) with NO2 to generate NO3. We found total VOC conversion to be dominated by reactions both with O3, which almost solely reacted with d-limonene, and also with OH, which reacted with d-limonene, other terpenes, alcohols, aldehydes, and aromatics. VOC oxidation rates increased with air exchange, outdoor O3, NO2 and d-limonene sources, and indoor photolysis rates; and they decreased with O3 deposition and nitric oxide (NO) sources. Photolysis was a strong OH formation mechanism for high NO, NO2, and HONO settings, but SCI/NO2 reactions weakly generated NO3 except for only a few cases. PMID:26855604

  10. Volatile organic compound conversion by ozone, hydroxyl radicals, and nitrate radicals in residential indoor air: Magnitudes and impacts of oxidant sources

    NASA Astrophysics Data System (ADS)

    Waring, Michael S.; Wells, J. Raymond

    2015-04-01

    Indoor chemistry may be initiated by reactions of ozone (O3), the hydroxyl radical (OH), or the nitrate radical (NO3) with volatile organic compounds (VOC). The principal indoor source of O3 is air exchange, while OH and NO3 formation are considered as primarily from O3 reactions with alkenes and nitrogen dioxide (NO2), respectively. Herein, we used time-averaged models for residences to predict O3, OH, and NO3 concentrations and their impacts on conversion of typical residential VOC profiles, within a Monte Carlo framework that varied inputs probabilistically. We accounted for established oxidant sources, as well as explored the importance of two newly realized indoor sources: (i) the photolysis of nitrous acid (HONO) indoors to generate OH and (ii) the reaction of stabilized Criegee intermediates (SCI) with NO2 to generate NO3. We found total VOC conversion to be dominated by reactions both with O3, which almost solely reacted with D-limonene, and also with OH, which reacted with D-limonene, other terpenes, alcohols, aldehydes, and aromatics. VOC oxidation rates increased with air exchange, outdoor O3, NO2 and D-limonene sources, and indoor photolysis rates; and they decreased with O3 deposition and nitric oxide (NO) sources. Photolysis was a strong OH formation mechanism for high NO, NO2, and HONO settings, but SCI/NO2 reactions weakly generated NO3 except for only a few cases.

  11. Screening of additives in plastics with high resolution time-of-flight mass spectrometry and different ionization sources: direct probe injection (DIP)-APCI, LC-APCI, and LC-ion booster ESI.

    PubMed

    Ballesteros-Gómez, Ana; Jonkers, Tim; Covaci, Adrian; de Boer, Jacob

    2016-04-01

    Plastics are complex mixtures consisting of a polymer and additives with different physico-chemical properties. We developed a broad screening method to elucidate the nature of compounds present in plastics used in electrical/electronic equipment commonly found at homes (e.g., electrical adaptors, computer casings, heaters). The analysis was done by (a) solvent extraction followed by liquid chromatography coupled to high accuracy/resolution time-of-flight mass spectrometry (TOFMS) with different ionization sources or (b) direct analysis of the solid by ambient mass spectrometry high accuracy/resolution TOFMS. The different ionization methods showed different selectivity and sensitivity for the different compound classes and were complementary. A variety of antioxidants, phthalates, UV filters, and flame retardants were found in most samples. Furthermore, some recently reported impurities or degradation products derived from flame retardants were identified, such as hydroxylated triphenyl phosphate and tetrabromobisphenol A monoglycidyl ether.

  12. Effect of protein source and protease addition on performance, blood metabolites and nutrient digestibility of turkeys fed on low-protein diets from 28 to 55 d post hatch.

    PubMed

    Shahir, M H; Rahimi, R; Taheri, H R; Heidariniya, A; Baradaran, N; Asadi Kermani, Z

    2016-06-01

    The objective of this study was to investigate the effect of a monocomponent protease and dietary inclusion of canola meal (CM) and poultry by-product meal (PBM) on growth performance, carcass characteristics and blood metabolites of turkeys fed on low crude protein (CP) diets from 28 to 55 d post hatch. Experimental treatments included control, maize-soybean meal diet including 258.3 g/kg CP; negative control 1 (NC1), maize-soybean meal diet with reduced CP (232.4 g/kg); NC2, control diet (CP, 258.3 g/kg) including CM (80 g/kg) and PBM (80 g/kg); NC3, maize-soybean meal diet with reduced CP (232.4 g/kg) including CM (80 g/kg) and PBM (80 g/kg). Also, the NC1 + P and NC3 + P diets were created by addition of protease enzyme (30 000 units/kg of diet) to the NC1 and NC3 diets, respectively. The NC3 group had lower body weight gain (BWG) compared to those fed on the control diet, and no improvement with enzyme addition (NC3 + P) was achieved. The protease addition to the NC1 diet (NC1 + P) improved BWG to the level of the control diet. The NC1 group had higher feed conversion ratio (FCR) compared to the control and NC3 + P, but protease addition to the NC1 diet improved FCR. Protease addition to the low CP diets resulted in higher nitrogen (N) retention than in the control and NC2 groups. Also, the NC1 + P and NC3 + P diets increased apparent ileal digestibility (AID) of CP compared to the control group. It was concluded that addition of CM (up to 80 g/kg) and PBM (up to 80 g/kg) to turkey diets had no negative effect on growth performance from 28 to 55 d of age. The NC1 + P group achieved the BWG of the control group which was partially due to increases in N retention and AID of CP, but the NC3 + P group failed to recover the growth losses. This difference implies that the efficacy of the protease may depend upon the protein source in the ration.

  13. Missing OH source in a suburban environment near Beijing: observed and modelled OH and HO2 concentrations in summer 2006

    NASA Astrophysics Data System (ADS)

    Lu, K. D.; Hofzumahaus, A.; Holland, F.; Bohn, B.; Brauers, T.; Fuchs, H.; Hu, M.; Häseler, R.; Kita, K.; Kondo, Y.; Li, X.; Lou, S. R.; Oebel, A.; Shao, M.; Zeng, L. M.; Wahner, A.; Zhu, T.; Zhang, Y. H.; Rohrer, F.

    2012-04-01

    Measurements of ambient OH and HO2 radicals were performed by laser induced fluorescence (LIF) during CAREBeijing2006 (Campaigns of Air Quality Research in Beijing and Surrounding Region 2006) at the suburban site Yufa in the south of Beijing in summer 2006. On most days, local air chemistry was influenced by aged air pollution that was advected by a slow, almost stagnant wind from southern regions. Observed daily maxima of OH and HO2* were in the range of (4-17) × 106 cm-3 and (2-24) × 108 cm-3, respectively. During daytime, OH reactivities were generally high (10-30 s-1) and mainly contributed by VOCs and their oxidation products. The comparison of modelled and measured HOx concentrations reveals a systematic underprediction of OH as a function of NO. A large discrepancy of a factor 2.6 is found at the lowest NO concentration encountered (0.1 ppb), whereas the discrepancy becomes insignificant above 1 ppb NO. This study extends similar observations from the Pearl-River Delta (PRD) in South China to a more urban environment. The OH discrepancy at Yufa can be resolved, if NO-independent additional OH recycling is assumed in the model. The postulated Leuven Isoprene Mechanism (LIM) has the potential to explain the gap between modelled and measured OH at Beijing taking into account conservative error estimates, but still lacks experimental confirmation. This and the hereby unresolved discrepancy at PRD suggest that other VOCs besides isoprene might be involved in the required, additional OH recycling. Fast primary production of ROx radicals up to 7 ppb h-1 was determined at Beijing which was dominated by the photolysis of O3, HONO, HCHO, and dicarbonyls. For a special case, 20 August, when the plume of Beijing city was encountered, a missing primary HOx source (≈ 3 ppb h-1) was determined under high NOx conditions similar to other urban areas like Mexico city. CAREBeijing2006 emphasizes the important role of OVOCs as a radical source and sink, and the need for

  14. Missing OH source in a suburban environment near Beijing: observed and modelled OH and HO2 concentrations in summer 2006

    NASA Astrophysics Data System (ADS)

    Lu, K. D.; Hofzumahaus, A.; Holland, F.; Bohn, B.; Brauers, T.; Fuchs, H.; Hu, M.; Häseler, R.; Kita, K.; Kondo, Y.; Li, X.; Lou, S. R.; Oebel, A.; Shao, M.; Zeng, L. M.; Wahner, A.; Zhu, T.; Zhang, Y. H.; Rohrer, F.

    2013-01-01

    Measurements of ambient OH and HO2 radicals were performed by laser induced fluorescence (LIF) during CAREBeijing2006 (Campaigns of Air Quality Research in Beijing and Surrounding Region 2006) at the suburban site Yufa in the south of Beijing in summer 2006. On most days, local air chemistry was influenced by aged air pollution that was advected by a slow, almost stagnant wind from southern regions. Observed daily concentration maxima were in the range of (4-17) × 106 cm-3 for OH and (2-24) × 108 cm-3 for HO2 (including an estimated interference of 25% from RO2). During daytime, OH reactivities were generally high (10-30 s-1) and mainly contributed by observed VOCs and their calculated oxidation products. The comparison of modelled and measured HOx concentrations reveals a systematic underprediction of OH as a function of NO. A large discrepancy of a factor 2.6 is found at the lowest NO concentration encountered (0.1 ppb), whereas the discrepancy becomes insignificant above 1 ppb NO. This study extends similar observations from the Pearl-River Delta (PRD) in South China to a more urban environment. The OH discrepancy at Yufa can be resolved, if NO-independent additional OH recycling is assumed in the model. The postulated Leuven Isoprene Mechanism (LIM) has the potential to explain the gap between modelled and measured OH at Beijing taking into account conservative error estimates, but lacks experimental confirmation. This and the hereby unresolved discrepancy at PRD suggest that other VOCs besides isoprene might be involved in the required, additional OH recycling. Fast primary production of ROx radicals up to 7 ppb h-1 was determined at Beijing which was dominated by the photolysis of O3, HONO, HCHO, and dicarbonyls. For a special case, 20 August, when the plume of Beijing city was encountered, a missing primary HOx source (about 3 ppb h-1) was determined under high NOx conditions similar to other urban areas like Mexico City. CAREBeijing2006 emphasizes the

  15. Novel tracer method to measure isotopic labeled gas-phase nitrous acid (HO15NO) in biogeochemical studies.

    PubMed

    Wu, Dianming; Kampf, Christopher J; Pöschl, Ulrich; Oswald, Robert; Cui, Junfang; Ermel, Michael; Hu, Chunsheng; Trebs, Ivonne; Sörgel, Matthias

    2014-07-15

    Gaseous nitrous acid (HONO), the protonated form of nitrite, contributes up to ∼60% to the primary formation of hydroxyl radical (OH), which is a key oxidant in the degradation of most air pollutants. Field measurements and modeling studies indicate a large unknown source of HONO during daytime. Here, we developed a new tracer method based on gas-phase stripping-derivatization coupled to liquid chromatography-mass spectrometry (LC-MS) to measure the 15N relative exceedance, ψ(15N), of HONO in the gas-phase. Gaseous HONO is quantitatively collected and transferred to an azo dye, purified by solid phase extraction (SPE), and analyzed using high performance liquid chromatography coupled to mass spectrometry (HPLC-MS). In the optimal working range of ψ(15N)=0.2-0.5, the relative standard deviation of ψ(15N) is <4%. The optimum pH and solvents for extraction by SPE and potential interferences are discussed. The method was applied to measure HO15NO emissions from soil in a dynamic chamber with and without spiking 15) labeled urea. The identification of HO15NO from soil with 15N urea addition confirmed biogenic emissions of HONO from soil. The method enables a new approach of studying the formation pathways of HONO and its role for atmospheric chemistry (e.g., ozone formation) and environmental tracer studies on the formation and conversion of gaseous HONO or aqueous NO2- as part of the biogeochemical nitrogen cycle, e.g., in the investigation of fertilization effects on soil HONO emissions and microbiological conversion of NO2- in the hydrosphere.

  16. Kentucky Department for Natural Resources and Environmental Protection permit application for air contaminant source: SRC-I demonstration plant, Newman, Kentucky. Supplement I. [Additional information on 38 items requested by KY/DNREP

    SciTech Connect

    Pearson, Jr., John F.

    1981-02-13

    In response to a letter from KY/DNREP, January 19, 1981, ICRC and DOE have prepared the enclosed supplement to the Kentucky Department for Natural Resources and Environmental Protection Permit Application for Air Contaminant Source for the SRC-I Demonstration Plant. Each of the 38 comments contained in the letter has been addressed in accordance with the discussions held in Frankfort on January 28, 1981, among representatives of KY/DNREP, EPA Region IV, US DOE, and ICRC. The questions raised involve requests for detailed information on the performance and reliability of proprietary equipment, back-up methods, monitoring plans for various pollutants, composition of wastes to flares, emissions estimates from particular operations, origin of baseline information, mathematical models, storage tanks, dusts, etc. (LTN)

  17. Additive Similarity Trees

    ERIC Educational Resources Information Center

    Sattath, Shmuel; Tversky, Amos

    1977-01-01

    Tree representations of similarity data are investigated. Hierarchical clustering is critically examined, and a more general procedure, called the additive tree, is presented. The additive tree representation is then compared to multidimensional scaling. (Author/JKS)

  18. Bioprocessing of “Hair Waste” by Paecilomyces lilacinus as a Source of a Bleach-Stable, Alkaline, and Thermostable Keratinase with Potential Application as a Laundry Detergent Additive: Characterization and Wash Performance Analysis

    PubMed Central

    Cavello, Ivana A.; Hours, Roque A.; Cavalitto, Sebastián F.

    2012-01-01

    Paecilomyces lilacinus (Thom) Samson LPS 876, a locally isolated fungal strain, was grown on minimal mineral medium containing “hair waste,” a residue from the hair-saving unhairing process, and produced a protease with keratinolytic activity. This enzyme was biochemically characterized. The optimum reaction conditions, determined with a response surface methodology, were 60°C and pH 6.0. It was remarkably stable in a wide range of pHs and temperatures. Addition of Ca2+, Mg2+, or sorbitol was found to be effective in increasing thermal stability of the protease. PMSF and Hg2+ inhibited the proteolytic activity indicating the presence of a thiol-dependent serine protease. It showed high stability toward surfactants, bleaching agents, and solvents. It was also compatible with commercial detergents (7 mg/mL) such as Ariel, Skip, Drive, and Ace, retaining more than 70% of its proteolytic activity in all detergents after 1 h of incubation at 40°C. Wash performance analysis revealed that this protease could effectively remove blood stains. From these properties, this enzyme may be considered as a potential candidate for future use in biotechnological processes, as well as in the formulation of laundry detergents. PMID:23365760

  19. Bioprocessing of "Hair Waste" by Paecilomyces lilacinus as a Source of a Bleach-Stable, Alkaline, and Thermostable Keratinase with Potential Application as a Laundry Detergent Additive: Characterization and Wash Performance Analysis.

    PubMed

    Cavello, Ivana A; Hours, Roque A; Cavalitto, Sebastián F

    2012-01-01

    Paecilomyces lilacinus (Thom) Samson LPS 876, a locally isolated fungal strain, was grown on minimal mineral medium containing "hair waste," a residue from the hair-saving unhairing process, and produced a protease with keratinolytic activity. This enzyme was biochemically characterized. The optimum reaction conditions, determined with a response surface methodology, were 60°C and pH 6.0. It was remarkably stable in a wide range of pHs and temperatures. Addition of Ca(2+), Mg(2+), or sorbitol was found to be effective in increasing thermal stability of the protease. PMSF and Hg(2+) inhibited the proteolytic activity indicating the presence of a thiol-dependent serine protease. It showed high stability toward surfactants, bleaching agents, and solvents. It was also compatible with commercial detergents (7 mg/mL) such as Ariel, Skip, Drive, and Ace, retaining more than 70% of its proteolytic activity in all detergents after 1 h of incubation at 40°C. Wash performance analysis revealed that this protease could effectively remove blood stains. From these properties, this enzyme may be considered as a potential candidate for future use in biotechnological processes, as well as in the formulation of laundry detergents.

  20. Polyimide processing additives

    NASA Technical Reports Server (NTRS)

    Pratt, J. R.; St. Clair, T. L.; Burks, H. D.; Stoakley, D. M.

    1987-01-01

    A method has been found for enhancing the melt flow of thermoplastic polyimides during processing. A high molecular weight 422 copoly(amic acid) or copolyimide was fused with approximately 0.05 to 5 pct by weight of a low molecular weight amic acid or imide additive, and this melt was studied by capillary rheometry. Excellent flow and improved composite properties on graphite resulted from the addition of a PMDA-aniline additive to LARC-TPI. Solution viscosity studies imply that amic acid additives temporarily lower molecular weight and, hence, enlarge the processing window. Thus, compositions containing the additive have a lower melt viscosity for a longer time than those unmodified.

  1. [Food additives and healthiness].

    PubMed

    Heinonen, Marina

    2014-01-01

    Additives are used for improving food structure or preventing its spoilage, for example. Many substances used as additives are also naturally present in food. The safety of additives is evaluated according to commonly agreed principles. If high concentrations of an additive cause adverse health effects for humans, a limit of acceptable daily intake (ADI) is set for it. An additive is a risk only when ADI is exceeded. The healthiness of food is measured on the basis of nutrient density and scientifically proven effects.

  2. Polylactides in additive biomanufacturing.

    PubMed

    Poh, Patrina S P; Chhaya, Mohit P; Wunner, Felix M; De-Juan-Pardo, Elena M; Schilling, Arndt F; Schantz, Jan-Thorsten; van Griensven, Martijn; Hutmacher, Dietmar W

    2016-12-15

    New advanced manufacturing technologies under the alias of additive biomanufacturing allow the design and fabrication of a range of products from pre-operative models, cutting guides and medical devices to scaffolds. The process of printing in 3 dimensions of cells, extracellular matrix (ECM) and biomaterials (bioinks, powders, etc.) to generate in vitro and/or in vivo tissue analogue structures has been termed bioprinting. To further advance in additive biomanufacturing, there are many aspects that we can learn from the wider additive manufacturing (AM) industry, which have progressed tremendously since its introduction into the manufacturing sector. First, this review gives an overview of additive manufacturing and both industry and academia efforts in addressing specific challenges in the AM technologies to drive toward AM-enabled industrial revolution. After which, considerations of poly(lactides) as a biomaterial in additive biomanufacturing are discussed. Challenges in wider additive biomanufacturing field are discussed in terms of (a) biomaterials; (b) computer-aided design, engineering and manufacturing; (c) AM and additive biomanufacturing printers hardware; and (d) system integration. Finally, the outlook for additive biomanufacturing was discussed.

  3. Additive Manufactured Product Integrity

    NASA Technical Reports Server (NTRS)

    Waller, Jess; Wells, Doug; James, Steve; Nichols, Charles

    2017-01-01

    NASA is providing key leadership in an international effort linking NASA and non-NASA resources to speed adoption of additive manufacturing (AM) to meet NASA's mission goals. Participants include industry, NASA's space partners, other government agencies, standards organizations and academia. Nondestructive Evaluation (NDE) is identified as a universal need for all aspects of additive manufacturing.

  4. Polyimide processing additives

    NASA Technical Reports Server (NTRS)

    Fletcher, James C. (Inventor); Pratt, J. Richard (Inventor); St.clair, Terry L. (Inventor); Stoakley, Diane M. (Inventor); Burks, Harold D. (Inventor)

    1992-01-01

    A process for preparing polyimides having enhanced melt flow properties is described. The process consists of heating a mixture of a high molecular weight poly-(amic acid) or polyimide with a low molecular weight amic acid or imide additive in the range of 0.05 to 15 percent by weight of additive. The polyimide powders so obtained show improved processability, as evidenced by lower melt viscosity by capillary rheometry. Likewise, films prepared from mixtures of polymers with additives show improved processability with earlier onset of stretching by TMA.

  5. Polyimide processing additives

    NASA Technical Reports Server (NTRS)

    Pratt, J. Richard (Inventor); St.clair, Terry L. (Inventor); Stoakley, Diane M. (Inventor); Burks, Harold D. (Inventor)

    1993-01-01

    A process for preparing polyimides having enhanced melt flow properties is described. The process consists of heating a mixture of a high molecular weight poly-(amic acid) or polyimide with a low molecular weight amic acid or imide additive in the range of 0.05 to 15 percent by weight of the additive. The polyimide powders so obtained show improved processability, as evidenced by lower melt viscosity by capillary rheometry. Likewise, films prepared from mixtures of polymers with additives show improved processability with earlier onset of stretching by TMA.

  6. Emission Sources and Chemical Composition of the Atmosphere of a Mega-city in South Asia

    NASA Astrophysics Data System (ADS)

    Husain, L.; Farhana, B. K.; Ghauri, B. M.

    2007-05-01

    . HONO and NH3 concentrations of up to 25 and 117 ppb were observed. A strong diurnal pattern was evident in the concentration of elemental and organic carbon which was perhaps controlled by variation in mixing heights. We used HYSPLIT4 air trajectories, intercomponent relationships and meteorological observations to explain the sources and the impacts of fog chemistry and mixing heights on atmospheric processing of the chemical constituents. Aerosols collected on this campaign were found to carry the signatures of emissions from Afghanistan, North and Central Pakistan, North India in addition to the local pollution sources. Statistical analysis suggests emissions from coal and oil combustion, industrial processes, building construction sites and biomass burning as the primary emission sources. Carbonaceous aerosols contributed about 69% of the PM2.5 mass. Findings of our study will improve the understanding of the critical roles and interactions between chemical composition and size of atmospheric particles, atmospheric boundary layer and meteorological phenomena that manipulate the chemistry of an urban atmosphere. The results should play a vital role in any strategy to regulate emissions and improve air quality in the region.

  7. Food Additives and Hyperkinesis

    ERIC Educational Resources Information Center

    Wender, Ester H.

    1977-01-01

    The hypothesis that food additives are causally associated with hyperkinesis and learning disabilities in children is reviewed, and available data are summarized. Available from: American Medical Association 535 North Dearborn Street Chicago, Illinois 60610. (JG)

  8. Smog control fuel additives

    SciTech Connect

    Lundby, W.

    1993-06-29

    A method is described of controlling, reducing or eliminating, ozone and related smog resulting from photochemical reactions between ozone and automotive or industrial gases comprising the addition of iodine or compounds of iodine to hydrocarbon-base fuels prior to or during combustion in an amount of about 1 part iodine per 240 to 10,000,000 parts fuel, by weight, to be accomplished by: (a) the addition of these inhibitors during or after the refining or manufacturing process of liquid fuels; (b) the production of these inhibitors for addition into fuel tanks, such as automotive or industrial tanks; or (c) the addition of these inhibitors into combustion chambers of equipment utilizing solid fuels for the purpose of reducing ozone.

  9. Water hyacinth a potential source for value addition: An overview.

    PubMed

    Sindhu, Raveendran; Binod, Parameswaran; Pandey, Ashok; Madhavan, Aravind; Alphonsa, Jose Anju; Vivek, Narisetty; Gnansounou, Edgard; Castro, Eulogio; Faraco, Vincenza

    2017-04-01

    Water hyacinth a fresh water aquatic plant is considered as a noxious weed in many parts of the world since it grows very fast and depletes nutrients and oxygen from water bodies adversely affecting the growth of both plants and animals. Hence conversion of this problematic weed to value added chemicals and fuels helps in the self-sustainability especially for developing countries. The present review discusses the various value added products and fuels which can be produced from water hyacinth, the recent research and developmental activities on the bioconversion of water hyacinth for the production of fuels and value added products as well as its possibilities and challenges in commercialization.

  10. 17 CFR 38.1201 - Additional sources for compliance.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... designing a futures contract, the designated contract market should conduct market research so that the... contract markets should derive a quantitative estimate of the deliverable supplies for the delivery...

  11. 10 CFR 1.3 - Sources of additional information.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... fall within an exemption to the Act's openness requirement and the Commission also has determined that... availability of NRC records under the Freedom of Information Act and Privacy Act of 1974 may be obtained...

  12. 32 CFR 2001.24 - Additional requirements.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 32 National Defense 6 2013-07-01 2013-07-01 false Additional requirements. 2001.24 Section 2001.24... Markings § 2001.24 Additional requirements. (a) Marking prohibitions. Markings other than “Top Secret... list for NSI portions.” The source list, as described in § 2001.22(c)(1)(ii), shall include...

  13. 32 CFR 2001.24 - Additional requirements.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 32 National Defense 6 2014-07-01 2014-07-01 false Additional requirements. 2001.24 Section 2001.24... Markings § 2001.24 Additional requirements. (a) Marking prohibitions. Markings other than “Top Secret... list for NSI portions.” The source list, as described in § 2001.22(c)(1)(ii), shall include...

  14. 32 CFR 2001.24 - Additional requirements.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 32 National Defense 6 2012-07-01 2012-07-01 false Additional requirements. 2001.24 Section 2001.24... Markings § 2001.24 Additional requirements. (a) Marking prohibitions. Markings other than “Top Secret... list for NSI portions.” The source list, as described in § 2001.22(c)(1)(ii), shall include...

  15. 32 CFR 2001.24 - Additional requirements.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 6 2010-07-01 2010-07-01 false Additional requirements. 2001.24 Section 2001.24... Markings § 2001.24 Additional requirements. (a) Marking prohibitions. Markings other than “Top Secret... list for NSI portions.” The source list, as described in § 2001.22(c)(1)(ii), shall include...

  16. Observation and modelling of OH and HO2 concentrations in the Pearl River Delta 2006: a missing OH source in a VOC rich atmosphere

    NASA Astrophysics Data System (ADS)

    Lu, K. D.; Rohrer, F.; Holland, F.; Fuchs, H.; Bohn, B.; Brauers, T.; Chang, C. C.; Häseler, R.; Hu, M.; Kita, K.; Kondo, Y.; Li, X.; Lou, S. R.; Nehr, S.; Shao, M.; Zeng, L. M.; Wahner, A.; Zhang, Y. H.; Hofzumahaus, A.

    2011-04-01

    Ambient OH and HO2 concentrations were measured by laser induced fluorescence (LIF) during the PRIDE-PRD2006 (Program of Regional Integrated Experiments of Air Quality over the Pearl River Delta, 2006) campaign at a rural site downwind of the megacity of Guangzhou in Southern China. The observed OH concentrations reached daily peak values of (15-26) × 106 cm-3 which are among the highest values so far reported for urban and suburban areas. The observed OH shows a consistent high correlation with j(O1D) over a broad range of NOx conditions. The correlation cannot be reproduced by model simulations, indicating that OH stabilizing processes are missing in current models. The observed OH exhibited a weak dependence on NOx in contrast to model predictions. While modelled and measured OH agree well at NO mixing ratios above 1 ppb, a continuously increasing underprediction of the observed OH is found towards lower NO concentrations, reaching a factor of 8 at 0.02 ppb NO. A dependence of the modelled-to-measured OH ratio on isoprene cannot be concluded from the PRD data. However, the magnitude of the ratio fits into the isoprene dependent trend that was reported from other campaigns in forested regions. Hofzumahaus et al. (2009) proposed an unknown OH recycling process without NO, in order to explain the high OH levels at PRD in the presence of high VOC reactivity and low NO. Taking a recently discovered interference in the LIF measurement of HO2 into account, the need for an additional HO2 → OH recycling process persists, but the required source strength may be up to 20% larger than previously determined. Recently postulated isoprene mechanisms by Lelieveld et al. (2008) and Peeters and Müller (2010) lead to significant enhancements of OH expected for PRD, but an underprediction of the observed OH by a factor of two remains at low NO (0.1-0.2 ppb). If the photolysis of hydroperoxy aldehydes from isoprene is as efficient as proposed by Peeters and Müller (2010), the

  17. Observation and modelling of OH and HO2 concentrations in the Pearl River Delta 2006: a missing OH source in a VOC rich atmosphere

    NASA Astrophysics Data System (ADS)

    Lu, K. D.; Rohrer, F.; Holland, F.; Fuchs, H.; Bohn, B.; Brauers, T.; Chang, C. C.; Häseler, R.; Hu, M.; Kita, K.; Kondo, Y.; Li, X.; Lou, S. R.; Nehr, S.; Shao, M.; Zeng, L. M.; Wahner, A.; Zhang, Y. H.; Hofzumahaus, A.

    2012-02-01

    Ambient OH and HO2 concentrations were measured by laser induced fluorescence (LIF) during the PRIDE-PRD2006 (Program of Regional Integrated Experiments of Air Quality over the Pearl River Delta, 2006) campaign at a rural site downwind of the megacity of Guangzhou in Southern China. The observed OH concentrations reached daily peak values of (15-26) × 106 cm-3 which are among the highest values so far reported for urban and suburban areas. The observed OH shows a consistent high correlation with j(O1D) over a broad range of NOx conditions. The correlation cannot be reproduced by model simulations, indicating that OH stabilizing processes are missing in current models. The observed OH exhibited a weak dependence on NOx in contrast to model predictions. While modelled and measured OH agree well at NO mixing ratios above 1 ppb, a continuously increasing underprediction of the observed OH is found towards lower NO concentrations, reaching a factor of 8 at 0.02 ppb NO. A dependence of the modelled-to-measured OH ratio on isoprene cannot be concluded from the PRD data. However, the magnitude of the ratio fits into the isoprene dependent trend that was reported from other campaigns in forested regions. Hofzumahaus et al. (2009) proposed an unknown OH recycling process without NO, in order to explain the high OH levels at PRD in the presence of high VOC reactivity and low NO. Taking a recently discovered interference in the LIF measurement of HO2 into account, the need for an additional HO2 → OH recycling process persists, but the required source strength may be up to 20% larger than previously determined. Recently postulated isoprene mechanisms by Lelieveld et al. (2008) and Peeters and Müller (2010) lead to significant enhancements of OH expected for PRD, but an underprediction of the observed OH by a factor of two remains at low NO (0.1-0.2 ppb). If the photolysis of hydroperoxy aldehydes from isoprene is as efficient as proposed by Peeters and Müller (2010), the

  18. Group Sparse Additive Models

    PubMed Central

    Yin, Junming; Chen, Xi; Xing, Eric P.

    2016-01-01

    We consider the problem of sparse variable selection in nonparametric additive models, with the prior knowledge of the structure among the covariates to encourage those variables within a group to be selected jointly. Previous works either study the group sparsity in the parametric setting (e.g., group lasso), or address the problem in the nonparametric setting without exploiting the structural information (e.g., sparse additive models). In this paper, we present a new method, called group sparse additive models (GroupSpAM), which can handle group sparsity in additive models. We generalize the ℓ1/ℓ2 norm to Hilbert spaces as the sparsity-inducing penalty in GroupSpAM. Moreover, we derive a novel thresholding condition for identifying the functional sparsity at the group level, and propose an efficient block coordinate descent algorithm for constructing the estimate. We demonstrate by simulation that GroupSpAM substantially outperforms the competing methods in terms of support recovery and prediction accuracy in additive models, and also conduct a comparative experiment on a real breast cancer dataset.

  19. Additive Manufacturing Infrared Inspection

    NASA Technical Reports Server (NTRS)

    Gaddy, Darrell

    2014-01-01

    Additive manufacturing is a rapid prototyping technology that allows parts to be built in a series of thin layers from plastic, ceramics, and metallics. Metallic additive manufacturing is an emerging form of rapid prototyping that allows complex structures to be built using various metallic powders. Significant time and cost savings have also been observed using the metallic additive manufacturing compared with traditional techniques. Development of the metallic additive manufacturing technology has advanced significantly over the last decade, although many of the techniques to inspect parts made from these processes have not advanced significantly or have limitations. Several external geometry inspection techniques exist such as Coordinate Measurement Machines (CMM), Laser Scanners, Structured Light Scanning Systems, or even traditional calipers and gages. All of the aforementioned techniques are limited to external geometry and contours or must use a contact probe to inspect limited internal dimensions. This presentation will document the development of a process for real-time dimensional inspection technique and digital quality record of the additive manufacturing process using Infrared camera imaging and processing techniques.

  20. Phenylethynyl Containing Reactive Additives

    NASA Technical Reports Server (NTRS)

    Connell, John W. (Inventor); Smith, Joseph G., Jr. (Inventor); Hergenrother, Paul M. (Inventor)

    2002-01-01

    Phenylethynyl containing reactive additives were prepared from aromatic diamine, containing phenylethvnvl groups and various ratios of phthalic anhydride and 4-phenylethynviphthalic anhydride in glacial acetic acid to form the imide in one step or in N-methyl-2-pvrrolidinone to form the amide acid intermediate. The reactive additives were mixed in various amounts (10% to 90%) with oligomers containing either terminal or pendent phenylethynyl groups (or both) to reduce the melt viscosity and thereby enhance processability. Upon thermal cure, the additives react and become chemically incorporated into the matrix and effect an increase in crosslink density relative to that of the host resin. This resultant increase in crosslink density has advantageous consequences on the cured resin properties such as higher glass transition temperature and higher modulus as compared to that of the host resin.

  1. Fused Lasso Additive Model

    PubMed Central

    Petersen, Ashley; Witten, Daniela; Simon, Noah

    2016-01-01

    We consider the problem of predicting an outcome variable using p covariates that are measured on n independent observations, in a setting in which additive, flexible, and interpretable fits are desired. We propose the fused lasso additive model (FLAM), in which each additive function is estimated to be piecewise constant with a small number of adaptively-chosen knots. FLAM is the solution to a convex optimization problem, for which a simple algorithm with guaranteed convergence to a global optimum is provided. FLAM is shown to be consistent in high dimensions, and an unbiased estimator of its degrees of freedom is proposed. We evaluate the performance of FLAM in a simulation study and on two data sets. Supplemental materials are available online, and the R package flam is available on CRAN. PMID:28239246

  2. Phenylethynyl Containing Reactive Additives

    NASA Technical Reports Server (NTRS)

    Connell, John W. (Inventor); Smith, Joseph G., Jr. (Inventor); Hergenrother, Paul M. (Inventor)

    2002-01-01

    Phenylethynyl containing reactive additives were prepared from aromatic diamines containing phenylethynyl groups and various ratios of phthalic anhydride and 4-phenylethynylphthalic anhydride in glacial acetic acid to form the imide in one step or in N-methyl-2-pyrrolidi none to form the amide acid intermediate. The reactive additives were mixed in various amounts (10% to 90%) with oligomers containing either terminal or pendent phenylethynyl groups (or both) to reduce the melt viscosity and thereby enhance processability. Upon thermal cure, the additives react and become chemically incorporated into the matrix and effect an increase in crosslink density relative to that of the host resin. This resultant increase in crosslink density has advantageous consequences on the cured resin properties such as higher glass transition temperature and higher modulus as compared to that of the host resin.

  3. Additives in plastics.

    PubMed Central

    Deanin, R D

    1975-01-01

    The polymers used in plastics are generally harmless. However, they are rarely used in pure form. In almost all commercial plastics, they are "compounded" with monomeric ingredients to improve their processing and end-use performance. In order of total volume used, these monomeric additives may be classified as follows: reinforcing fibers, fillers, and coupling agents; plasticizers; colorants; stabilizers (halogen stabilizers, antioxidants, ultraviolet absorbers, and biological preservatives); processing aids (lubricants, others, and flow controls); flame retardants, peroxides; and antistats. Some information is already available, and much more is needed, on potential toxicity and safe handling of these additives during processing and manufacture of plastics products. PMID:1175566

  4. Additives in plastics.

    PubMed

    Deanin, R D

    1975-06-01

    The polymers used in plastics are generally harmless. However, they are rarely used in pure form. In almost all commercial plastics, they are "compounded" with monomeric ingredients to improve their processing and end-use performance. In order of total volume used, these monomeric additives may be classified as follows: reinforcing fibers, fillers, and coupling agents; plasticizers; colorants; stabilizers (halogen stabilizers, antioxidants, ultraviolet absorbers, and biological preservatives); processing aids (lubricants, others, and flow controls); flame retardants, peroxides; and antistats. Some information is already available, and much more is needed, on potential toxicity and safe handling of these additives during processing and manufacture of plastics products.

  5. Biobased lubricant additives

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fully biobased lubricants are those formulated using all biobased ingredients, i.e. biobased base oils and biobased additives. Such formulations provide the maximum environmental, safety, and economic benefits expected from a biobased product. Currently, there are a number of biobased base oils that...

  6. More Than Additional Space...

    ERIC Educational Resources Information Center

    CEFP Journal, 1973

    1973-01-01

    A much needed addition to the Jamestown Elementary School turned out to be more than an expansion of walls for more space. A new educational program, a limited budget, and a short time line were tackled on a team approach basis and were successfully resolved. (Author)

  7. Vinyl capped addition polyimides

    NASA Technical Reports Server (NTRS)

    Vannucci, Raymond D. (Inventor); Malarik, Diane C. (Inventor); Delvigs, Peter (Inventor)

    1991-01-01

    Polyimide resins (PMR) are generally useful where high strength and temperature capabilities are required (at temperatures up to about 700 F). Polyimide resins are particularly useful in applications such as jet engine compressor components, for example, blades, vanes, air seals, air splitters, and engine casing parts. Aromatic vinyl capped addition polyimides are obtained by reacting a diamine, an ester of tetracarboxylic acid, and an aromatic vinyl compound. Low void materials with improved oxidative stability when exposed to 700 F air may be fabricated as fiber reinforced high molecular weight capped polyimide composites. The aromatic vinyl capped polyimides are provided with a more aromatic nature and are more thermally stable than highly aliphatic, norbornenyl-type end-capped polyimides employed in PMR resins. The substitution of aromatic vinyl end-caps for norbornenyl end-caps in addition polyimides results in polymers with improved oxidative stability.

  8. Electrophilic addition of astatine

    SciTech Connect

    Norseev, Yu.V.; Vasaros, L.; Nhan, D.D.; Huan, N.K.

    1988-03-01

    It has been shown for the first time that astatine is capable of undergoing addition reactions to unsaturated hydrocarbons. A new compound of astatine, viz., ethylene astatohydrin, has been obtained, and its retention numbers of squalane, Apiezon, and tricresyl phosphate have been found. The influence of various factors on the formation of ethylene astatohydrin has been studied. It has been concluded on the basis of the results obtained that the univalent cations of astatine in an acidic medium is protonated hypoastatous acid.

  9. Functional Generalized Additive Models.

    PubMed

    McLean, Mathew W; Hooker, Giles; Staicu, Ana-Maria; Scheipl, Fabian; Ruppert, David

    2014-01-01

    We introduce the functional generalized additive model (FGAM), a novel regression model for association studies between a scalar response and a functional predictor. We model the link-transformed mean response as the integral with respect to t of F{X(t), t} where F(·,·) is an unknown regression function and X(t) is a functional covariate. Rather than having an additive model in a finite number of principal components as in Müller and Yao (2008), our model incorporates the functional predictor directly and thus our model can be viewed as the natural functional extension of generalized additive models. We estimate F(·,·) using tensor-product B-splines with roughness penalties. A pointwise quantile transformation of the functional predictor is also considered to ensure each tensor-product B-spline has observed data on its support. The methods are evaluated using simulated data and their predictive performance is compared with other competing scalar-on-function regression alternatives. We illustrate the usefulness of our approach through an application to brain tractography, where X(t) is a signal from diffusion tensor imaging at position, t, along a tract in the brain. In one example, the response is disease-status (case or control) and in a second example, it is the score on a cognitive test. R code for performing the simulations and fitting the FGAM can be found in supplemental materials available online.

  10. Temperature compensated current source

    NASA Technical Reports Server (NTRS)

    Breuer, D. R. (Inventor)

    1971-01-01

    A current source was designed which is substantially independent of variations of temperature. The current source may be made either to have a linear dependence upon changes of temperature or, by the simple addition of a resistor, may be made substantially independent of temperature variations. Since the current source consists only of transistors of one conductivity type and resistors, it is ideally suited for manufacture in the form of a monolithic integrated circuit.

  11. An Additive Manufacturing Test Artifact

    PubMed Central

    Moylan, Shawn; Slotwinski, John; Cooke, April; Jurrens, Kevin; Donmez, M Alkan

    2014-01-01

    A test artifact, intended for standardization, is proposed for the purpose of evaluating the performance of additive manufacturing (AM) systems. A thorough analysis of previously proposed AM test artifacts as well as experience with machining test artifacts have inspired the design of the proposed test artifact. This new artifact is designed to provide a characterization of the capabilities and limitations of an AM system, as well as to allow system improvement by linking specific errors measured in the test artifact to specific sources in the AM system. The proposed test artifact has been built in multiple materials using multiple AM technologies. The results of several of the builds are discussed, demonstrating how the measurement results can be used to characterize and improve a specific AM system. PMID:26601039

  12. An Additive Manufacturing Test Artifact.

    PubMed

    Moylan, Shawn; Slotwinski, John; Cooke, April; Jurrens, Kevin; Donmez, M Alkan

    2014-01-01

    A test artifact, intended for standardization, is proposed for the purpose of evaluating the performance of additive manufacturing (AM) systems. A thorough analysis of previously proposed AM test artifacts as well as experience with machining test artifacts have inspired the design of the proposed test artifact. This new artifact is designed to provide a characterization of the capabilities and limitations of an AM system, as well as to allow system improvement by linking specific errors measured in the test artifact to specific sources in the AM system. The proposed test artifact has been built in multiple materials using multiple AM technologies. The results of several of the builds are discussed, demonstrating how the measurement results can be used to characterize and improve a specific AM system.

  13. Siloxane containing addition polyimides

    NASA Technical Reports Server (NTRS)

    Maudgal, S.; St. Clair, T. L.

    1984-01-01

    Addition polyimide oligomers have been synthesized from bis(gamma-aminopropyl) tetramethyldisiloxane and 3, 3', 4, 4'-benzophenonetetracarboxylic dianhydride using a variety of latent crosslinking groups as endcappers. The prepolymers were isolated and characterized for solubility (in amide, chlorinated and ether solvents), melt flow and cure properties. The most promising systems, maleimide and acetylene terminated prepolymers, were selected for detailed study. Graphite cloth reinforced composites were prepared and properties compared with those of graphite/Kerimid 601, a commercially available bismaleimide. Mixtures of the maleimide terminated system with Kerimid 601, in varying proportions, were also studied.

  14. Platelet additive solution - electrolytes.

    PubMed

    Azuma, Hiroshi; Hirayama, Junichi; Akino, Mitsuaki; Ikeda, Hisami

    2011-06-01

    Recent attention to solutions that replace most or all plasma in platelet concentrates, while maintaining satisfactory platelet function, is motivated by the potential of plasma reduction or depletion to mitigate various transfusion-related adverse events. This report considers the electrolytic composition of previously described platelet additive solutions, in order to draw general conclusions about what is required for platelet function and longevity. The optimal concentrations of Na(+) and Cl(-) are 69-115 mM. The presence of both K(+) and Mg(2+) in platelet suspension at nearly physiological concentrations (3-5mM and 1.5-3mM, respectively) is indispensable for good preservation capacity because both electrolytes are required to prevent platelet activation. In contrast to K(+) and Mg(2+), Ca(2+) may not be important because no free Ca(2+) is available in M-sol, which showed excellent platelet preservation capacity at less than 5% plasma concentration. The importance of bicarbonate (approximately 40 mM) can be recognized when the platelets are suspended in additive solution under less than 5% residual plasma concentration.

  15. Additive composition, for gasoline

    SciTech Connect

    Vataru, M.

    1989-01-10

    An admixture is described that comprises Diesel fuel and an additive composition added thereto which is between about 0.05 to about 2.0 percent by weight of the fuel, the composition comprising: (a) between about 0.05 and 25% relative weight parts of an organic peroxide, and (b) between about 0.1 and 25% relative weight parts of detergent selected from the component group that consists of: (i) fatty amines; (ii) ethoxylated and propoxylated derivatives of fatty amines; (iii) fatty diamines; (iv) fatty imidazlines; (v) polymeric amines and derivatives thereof; (vi) combination of one or more of the (i) through (v) components with carboxylic acid or acids having from three to forth carbon atoms, (c) from about 99.0 to about 50% by weight of a hydrocarbon solvent.

  16. Teardrop bladder: additional considerations

    SciTech Connect

    Wechsler, R.J.; Brennan, R.E.

    1982-07-01

    Nine cases of teardrop bladder (TDB) seen at excretory urography are presented. In some of these patients, the iliopsoas muscles were at the upper limit of normal in size, and additional evaluation of the perivesical structures with computed tomography (CT) was necessary. CT demonstrated only hypertrophied muscles with or without perivesical fat. The psoas muscles and pelvic width were measured in 8 patients and compared with the measurements of a control group of males without TDB. Patients with TDB had large iliopsoas muscles and narrow pelves compared with the control group. The psoas muscle width/pelvic width ratio was significantly greater (p < 0.0005) in patients with TDB than in the control group, with values of 1.04 + 0.05 and 0.82 + 0.09, respectively. It is concluded that TDB is not an uncommon normal variant in black males. Both iliopsoas muscle hypertrophy and a narrow pelvis are factors that predispose a patient to TDB.

  17. New addition curing polyimides

    NASA Technical Reports Server (NTRS)

    Frimer, Aryeh A.; Cavano, Paul

    1991-01-01

    In an attempt to improve the thermal-oxidative stability (TOS) of PMR-type polymers, the use of 1,4-phenylenebis (phenylmaleic anhydride) PPMA, was evaluated. Two series of nadic end-capped addition curing polyimides were prepared by imidizing PPMA with either 4,4'-methylene dianiline or p-phenylenediamine. The first resulted in improved solubility and increased resin flow while the latter yielded a compression molded neat resin sample with a T(sub g) of 408 C, close to 70 C higher than PME-15. The performance of these materials in long term weight loss studies was below that of PMR-15, independent of post-cure conditions. These results can be rationalized in terms of the thermal lability of the pendant phenyl groups and the incomplete imidization of the sterically congested PPMA. The preparation of model compounds as well as future research directions are discussed.

  18. Perspectives on Additive Manufacturing

    NASA Astrophysics Data System (ADS)

    Bourell, David L.

    2016-07-01

    Additive manufacturing (AM) has skyrocketed in visibility commercially and in the public sector. This article describes the development of this field from early layered manufacturing approaches of photosculpture, topography, and material deposition. Certain precursors to modern AM processes are also briefly described. The growth of the field over the last 30 years is presented. Included is the standard delineation of AM technologies into seven broad categories. The economics of AM part generation is considered, and the impacts of the economics on application sectors are described. On the basis of current trends, the future outlook will include a convergence of AM fabricators, mass-produced AM fabricators, enabling of topology optimization designs, and specialization in the AM legal arena. Long-term developments with huge impact are organ printing and volume-based printing.

  19. Sewage sludge additive

    NASA Technical Reports Server (NTRS)

    Kalvinskas, J. J.; Mueller, W. A.; Ingham, J. D. (Inventor)

    1980-01-01

    The additive is for a raw sewage treatment process of the type where settling tanks are used for the purpose of permitting the suspended matter in the raw sewage to be settled as well as to permit adsorption of the dissolved contaminants in the water of the sewage. The sludge, which settles down to the bottom of the settling tank is extracted, pyrolyzed and activated to form activated carbon and ash which is mixed with the sewage prior to its introduction into the settling tank. The sludge does not provide all of the activated carbon and ash required for adequate treatment of the raw sewage. It is necessary to add carbon to the process and instead of expensive commercial carbon, coal is used to provide the carbon supplement.

  20. Additive lattice kirigami.

    PubMed

    Castle, Toen; Sussman, Daniel M; Tanis, Michael; Kamien, Randall D

    2016-09-01

    Kirigami uses bending, folding, cutting, and pasting to create complex three-dimensional (3D) structures from a flat sheet. In the case of lattice kirigami, this cutting and rejoining introduces defects into an underlying 2D lattice in the form of points of nonzero Gaussian curvature. A set of simple rules was previously used to generate a wide variety of stepped structures; we now pare back these rules to their minimum. This allows us to describe a set of techniques that unify a wide variety of cut-and-paste actions under the rubric of lattice kirigami, including adding new material and rejoining material across arbitrary cuts in the sheet. We also explore the use of more complex lattices and the different structures that consequently arise. Regardless of the choice of lattice, creating complex structures may require multiple overlapping kirigami cuts, where subsequent cuts are not performed on a locally flat lattice. Our additive kirigami method describes such cuts, providing a simple methodology and a set of techniques to build a huge variety of complex 3D shapes.

  1. Ceramics with Different Additives

    NASA Astrophysics Data System (ADS)

    Wang, Juanjuan; Feng, Lajun; Lei, Ali; Zhao, Kang; Yan, Aijun

    2014-09-01

    Li2CO3, MgCO3, BaCO3, and Bi2O3 dopants were introduced into CaCu3Ti4O12 (CCTO) ceramics in order to improve the dielectric properties. The CCTO ceramics were prepared by conventional solid-state reaction method. The phase structure, microstructure, and dielectric behavior were carefully investigated. The pure structure without any impurity phases can be confirmed by the x-ray diffraction patterns. Scanning Electron Microscopy (SEM) analysis illuminated that the grains of Ca0.90Li0.20Cu3Ti4O12 ceramics were greater than that of pure CCTO. It was important for the properties of the CCTO ceramics to study the additives in complex impedance spectroscopy. It was found that the Ca0.90Li0.20Cu3Ti4O12 ceramics had the higher permittivity (>45000), the lower dielectric loss (<0.025) than those of CCTO at 1 kHz at room temperature and good temperature stability from -30 to 75 °C.

  2. Additive lattice kirigami

    PubMed Central

    Castle, Toen; Sussman, Daniel M.; Tanis, Michael; Kamien, Randall D.

    2016-01-01

    Kirigami uses bending, folding, cutting, and pasting to create complex three-dimensional (3D) structures from a flat sheet. In the case of lattice kirigami, this cutting and rejoining introduces defects into an underlying 2D lattice in the form of points of nonzero Gaussian curvature. A set of simple rules was previously used to generate a wide variety of stepped structures; we now pare back these rules to their minimum. This allows us to describe a set of techniques that unify a wide variety of cut-and-paste actions under the rubric of lattice kirigami, including adding new material and rejoining material across arbitrary cuts in the sheet. We also explore the use of more complex lattices and the different structures that consequently arise. Regardless of the choice of lattice, creating complex structures may require multiple overlapping kirigami cuts, where subsequent cuts are not performed on a locally flat lattice. Our additive kirigami method describes such cuts, providing a simple methodology and a set of techniques to build a huge variety of complex 3D shapes. PMID:27679822

  3. Magnolol and honokiol exert a synergistic anti-tumor effect through autophagy and apoptosis in human glioblastomas.

    PubMed

    Cheng, Yu-Chen; Hueng, Dueng-Yuan; Huang, Hua-Yin; Chen, Jang-Yi; Chen, Ying

    2016-05-17

    Glioblastoma (GBM) is a malignant brain tumor associated with a high mortality rate. The aim of this study is to investigate the synergistic effects of honokiol (Hono) and magnolol (Mag), extracted from Magnolia officinalis, on cytotoxicity and inhibition of human GBM tumor progression in cellular and animal models. In comparison with Hono or Mag alone, co-treatment with Hono and Mag (Hono-Mag) decreased cyclin A, D1 and cyclin-dependent kinase 2, 4, 6 significantly, leading to cell cycle arrest in U87MG and LN229 human glioma cells. In addition, phosphorylated phosphoinositide 3-kinase (p-PI3K), p-Akt, and Ki67 were decreased after Hono-Mag treatment, showing proliferation inhibition. Hono-Mag treatment also reduced p-p38 and p-JNK but elevated p-ERK expression. Besides, Hono-Mag treatment induced autophagy and intrinsic and extrinsic apoptosis. Both ERK and autophagy inhibitors enhanced Hono-Mag-induced apoptosis in LN229 cells, indicating a rescuer role of ERK. In human GBM orthotopic xenograft model, the Hono-Mag treatment inhibited the tumor progression and induced apoptosis more efficiently than Temozolomide, Hono, or Mag group. In conclusion, the Hono-Mag exerts a synergistic anti-tumor effect by inhibiting cell proliferation and inducing autophagy and apoptosis in human GBM cells. The Hono-Mag may be applied as an adjuvant therapy to improve the therapeutic efficacy of GBM treatment.

  4. Nonpoint Sources.

    ERIC Educational Resources Information Center

    Browne, F. X.

    1978-01-01

    Presented a literature review of nonpoint source effects on water quality and pollution covering: (1) water quality effects; (2) watershed studies; (3) nonpoint source models; and nonpoint source controls. A list of 122 references published in 1976 and 1977 is also presented. (HM)

  5. Observations of Radical Precursors during TexAQS II: Findings and Implications

    NASA Astrophysics Data System (ADS)

    Olaguer, E. P.; Lefer, B. L.; Rappenglueck, B.; Pinto, J. P.

    2009-12-01

    The Texas Environmental Research Consortium (TERC) sponsored and helped organize significant components of the Second Texas Air Quality Study (TexAQS II). Some of the TERC-sponsored experiments, most notably those associated with the TexAQS II Radical and Aerosol Measurement Project (TRAMP) sited on top of the Moody Tower at the University of Houston, found evidence for the importance of short-lived radical sources such as formaldehyde (HCHO) and nitrous acid (HONO) in increasing ozone productivity. During TRAMP, daytime HCHO pulses as large as 32 ppb were observed and attributed to industrial activities upwind in the Houston Ship Channel (HSC), and HCHO peaks as large as 52 ppb were detected by in-situ surface monitors in the HSC. In addition, an instrumented Piper Aztec aircraft observed plumes of apparent primary formaldehyde in flares from petrochemical facilities in the HSC. In one such combustion plume, depleted of ozone by large NOx emissions, the Piper Aztec measured an HCHO-to-CO ratio three times that of mobile sources. HCHO from uncounted primary sources or ozonolysis of underestimated olefin emissions could significantly increase ozone productivity in Houston beyond previous expectations. Simulations with the CAMx model show that additional emissions of HCHO from industrial flares can increase peak ozone in Houston by up to 30 ppb, depending on conditions in the planetary boundary layer. Other findings from TexAQS II include significant concentrations of HONO throughout the day, well in excess of current air quality model predictions, with large nocturnal vertical gradients indicating a surface or near-surface source of HONO, and large concentrations of night-time radicals (~30 ppt HO2). Additional HONO sources could increase daytime ozone by more than 10 ppb. Improving the representation of primary and secondary HCHO and HONO in air quality models could enhance the effectiveness of simulated control strategies, and thus make ozone attainment

  6. 33 CFR 214.4 - Additional authority.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... DEFENSE EMERGENCY SUPPLIES OF DRINKING WATER § 214.4 Additional authority. Section 82(2), Pub. L. 93-251... of clean drinking water, on such terms as he determines to be advisable, to any locality which he finds is confronted with a source of contaminated drinking water causing or likely to cause...

  7. 40 CFR 412.47 - Additional measures.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 28 2010-07-01 2010-07-01 true Additional measures. 412.47 Section 412.47 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS CONCENTRATED ANIMAL FEEDING OPERATIONS (CAFO) POINT SOURCE CATEGORY Swine, Poultry, and...

  8. 40 CFR 412.47 - Additional measures.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 29 2014-07-01 2012-07-01 true Additional measures. 412.47 Section 412.47 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS CONCENTRATED ANIMAL FEEDING OPERATIONS (CAFO) POINT SOURCE CATEGORY Swine, Poultry, and...

  9. 40 CFR 412.47 - Additional measures.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 30 2012-07-01 2012-07-01 false Additional measures. 412.47 Section 412.47 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS CONCENTRATED ANIMAL FEEDING OPERATIONS (CAFO) POINT SOURCE CATEGORY Swine, Poultry, and...

  10. Microwave ion source

    SciTech Connect

    Leung, Ka-Ngo; Reijonen, Jani; Thomae, Rainer W.

    2005-07-26

    A compact microwave ion source has a permanent magnet dipole field, a microwave launcher, and an extractor parallel to the source axis. The dipole field is in the form of a ring. The microwaves are launched from the middle of the dipole ring using a coaxial waveguide. Electrons are heated using ECR in the magnetic field. The ions are extracted from the side of the source from the middle of the dipole perpendicular to the source axis. The plasma density can be increased by boosting the microwave ion source by the addition of an RF antenna. Higher charge states can be achieved by increasing the microwave frequency. A xenon source with a magnetic pinch can be used to produce intense EUV radiation.

  11. Photoenhanced nitrous acid formation upon NO2 uptake on tannic and gentisic acid films

    NASA Astrophysics Data System (ADS)

    Sosedova, Yulia; Rouvière, Aurélie; Ammann, Markus

    2010-05-01

    The heterogeneous chemistry of nitrogen dioxide (NO2) is a potential source of nitrous acid (HONO). Hydroxy and methoxy substituted phenols may play a significant role in the aqueous-phase chemistry occurring on the ground or within aerosol particles in air masses affected by biomass burning. It is well established that electron transfer between phenols and NO2 in alkaline aqueous solutions is fast and could be a source of nitrite in the aqueous phase and HONO in the gas phase. However its kinetics is very slow under atmospheric conditions. The role of phenolic species as electron donors has also been suspected to be responsible for the photoenhanced transformation of NO2 to HONO over humic acids [1]. In this study we used tannic (TA) and gentisic (GA) as another proxy for atmospheric phenolic compounds. TA was shown to easily decompose under near UV light irradiation [2] resulting in oxidized products that might change the hygroscopic properties of the original material or have some potential photosensitizing effect. It was interesting to check the hypothesis that the presence of such products could lead to photoenhanced HONO formation upon NO2 uptake to aqueous surfaces containing TA. Experiments were performed in a horizontal coated wall flow tube (40 cm × 5.9 cm i.d.) circularly surrounded by 7 fluorescence lamps (UV: 300-420 nm, or visible: 400-750 nm), in an air cooled lamp housing. The inner surface coating was containing ~0.5 mg/cm-2 of either TA or GA, and was operated under RH 20-80%, 21-23 °C and ambient pressure. Concentration of HONO in the gas phase at the flow tube exit was measured with a LOPAP (Long Path Absorption Spectrometer). The uptake coefficient (γ) leading to NO2 to HONO conversion above aqueous films containing GA or TA in the dark was in the range 4×10-7 - 2×10-6. The photochemically enhanced HONO production was demonstrated by UV irradiation of the GA or TA coatings being in contact with gaseous NO2. In this case γ was 3-10 times

  12. Neutron Characterization for Additive Manufacturing

    NASA Technical Reports Server (NTRS)

    Watkins, Thomas; Bilheux, Hassina; An, Ke; Payzant, Andrew; DeHoff, Ryan; Duty, Chad; Peter, William; Blue, Craig; Brice, Craig A.

    2013-01-01

    Oak Ridge National Laboratory (ORNL) is leveraging decades of experience in neutron characterization of advanced materials together with resources such as the Spallation Neutron Source (SNS) and the High Flux Isotope Reactor (HFIR) shown in Fig. 1 to solve challenging problems in additive manufacturing (AM). Additive manufacturing, or three-dimensional (3-D) printing, is a rapidly maturing technology wherein components are built by selectively adding feedstock material at locations specified by a computer model. The majority of these technologies use thermally driven phase change mechanisms to convert the feedstock into functioning material. As the molten material cools and solidifies, the component is subjected to significant thermal gradients, generating significant internal stresses throughout the part (Fig. 2). As layers are added, inherent residual stresses cause warping and distortions that lead to geometrical differences between the final part and the original computer generated design. This effect also limits geometries that can be fabricated using AM, such as thin-walled, high-aspect- ratio, and overhanging structures. Distortion may be minimized by intelligent toolpath planning or strategic placement of support structures, but these approaches are not well understood and often "Edisonian" in nature. Residual stresses can also impact component performance during operation. For example, in a thermally cycled environment such as a high-pressure turbine engine, residual stresses can cause components to distort unpredictably. Different thermal treatments on as-fabricated AM components have been used to minimize residual stress, but components still retain a nonhomogeneous stress state and/or demonstrate a relaxation-derived geometric distortion. Industry, federal laboratory, and university collaboration is needed to address these challenges and enable the U.S. to compete in the global market. Work is currently being conducted on AM technologies at the ORNL

  13. Ion source

    DOEpatents

    Leung, Ka-Ngo; Ehlers, Kenneth W.

    1984-01-01

    A magnetic filter for an ion source reduces the production of undesired ion species and improves the ion beam quality. High-energy ionizing electrons are confined by the magnetic filter to an ion source region, where the high-energy electrons ionize gas molecules. One embodiment of the magnetic filter uses permanent magnets oriented to establish a magnetic field transverse to the direction of travel of ions from the ion source region to the ion extraction region. In another embodiment, low energy 16 eV electrons are injected into the ion source to dissociate gas molecules and undesired ion species into desired ion species.

  14. Photonic crystal light source

    DOEpatents

    Fleming, James G.; Lin, Shawn-Yu; Bur, James A.

    2004-07-27

    A light source is provided by a photonic crystal having an enhanced photonic density-of-states over a band of frequencies and wherein at least one of the dielectric materials of the photonic crystal has a complex dielectric constant, thereby producing enhanced light emission at the band of frequencies when the photonic crystal is heated. The dielectric material can be a metal, such as tungsten. The spectral properties of the light source can be easily tuned by modification of the photonic crystal structure and materials. The photonic crystal light source can be heated electrically or other heating means. The light source can further include additional photonic crystals that exhibit enhanced light emission at a different band of frequencies to provide for color mixing. The photonic crystal light source may have applications in optical telecommunications, information displays, energy conversion, sensors, and other optical applications.

  15. Nuclear electric power sources

    NASA Technical Reports Server (NTRS)

    Singh, J. J.

    1978-01-01

    Measurements on radioactive commercial p-n junction silicon cells show that these units are capable of delivering several hundred microwatts per curie of Am-241 alpha source, indicating their usefulness in such electronic devices as hearing aids, heart pacemakers, electronic watches, delay timers and nuclear dosimeter chargers. It is concluded that the Am-241 sources are superior to the beta sources used previously, because of higher alpha specific ionization and simultaneous production of low energy photons which are easily converted into photoelectrons for additional power.

  16. ION SOURCE

    DOEpatents

    Martina, E.F.

    1958-04-22

    An improved ion source particularly adapted to provide an intense beam of ions with minimum neutral molecule egress from the source is described. The ion source structure includes means for establishing an oscillating electron discharge, including an apertured cathode at one end of the discharge. The egress of ions from the source is in a pencil like beam. This desirable form of withdrawal of the ions from the plasma created by the discharge is achieved by shaping the field at the aperture of the cathode. A tubular insulator is extended into the plasma from the aperture and in cooperation with the electric fields at the cathode end of the discharge focuses the ions from the source,

  17. Effusion plate using additive manufacturing methods

    DOEpatents

    Johnson, Thomas Edward; Keener, Christopher Paul; Ostebee, Heath Michael; Wegerif, Daniel Gerritt

    2016-04-12

    Additive manufacturing techniques may be utilized to construct effusion plates. Such additive manufacturing techniques may include defining a configuration for an effusion plate having one or more internal cooling channels. The manufacturing techniques may further include depositing a powder into a chamber, applying an energy source to the deposited powder, and consolidating the powder into a cross-sectional shape corresponding to the defined configuration. Such methods may be implemented to construct an effusion plate having one or more channels with a curved cross-sectional geometry.

  18. Light Source

    NASA Technical Reports Server (NTRS)

    1993-01-01

    Research on food growth for long duration spacecraft has resulted in a light source for growing plants indoors known as Qbeam, a solid state light source consisting of a control unit and lamp. The light source, manufactured by Quantum Devices, Inc., is not very hot, although it generates high intensity radiation. When Ron Ignatius, an industrial partner of WCSAR, realized that terrestrial plant research lighting was not energy efficient enough for space use, he and WCSAR began to experiment with light emitting diodes. A line of LED products was developed, and QDI was formed to market the technology. An LED-based cancer treatment device is currently under development.

  19. Energetic additive manufacturing process with feed wire

    DOEpatents

    Harwell, Lane D.; Griffith, Michelle L.; Greene, Donald L.; Pressly, Gary A.

    2000-11-07

    A process for additive manufacture by energetic wire deposition is described. A source wire is fed into a energy beam generated melt-pool on a growth surface as the melt-pool moves over the growth surface. This process enables the rapid prototyping and manufacture of fully dense, near-net shape components, as well as cladding and welding processes. Alloys, graded materials, and other inhomogeneous materials can be grown using this process.

  20. NEUTRON SOURCES

    DOEpatents

    Richmond, J.L.; Wells, C.E.

    1963-01-15

    A neutron source is obtained without employing any separate beryllia receptacle, as was formerly required. The new method is safer and faster, and affords a source with both improved yield and symmetry of neutron emission. A Be container is used to hold and react with Pu. This container has a thin isolating layer that does not obstruct the desired Pu--Be reaction and obviates procedures previously employed to disassemble and remove a beryllia receptacle. (AEC)

  1. How Safe Are Color Additives?

    MedlinePlus

    ... Home For Consumers Consumer Updates How Safe are Color Additives? Share Tweet Linkedin Pin it More sharing ... Consumer Updates RSS Feed Download PDF (380 K) Color additives give the red tint to your fruit ...

  2. Detergent Additive for Lubricating Oils,

    DTIC Science & Technology

    The Russian patent pertains to a method of producing additives for lubricating oils . A method is known for producing an antiwear additive for... lubricating oils by processing phenols with phosphorus oxychloride, phosphoric acid esters are obtained. In order to give the additive detergent properties

  3. Soil surface acidity plays a determining role in the atmospheric-terrestrial exchange of nitrous acid

    PubMed Central

    Donaldson, Melissa A.; Bish, David L.; Raff, Jonathan D.

    2014-01-01

    Nitrous acid (HONO) is an important hydroxyl (OH) radical source that is formed on both ground and aerosol surfaces in the well-mixed boundary layer. Recent studies report the release of HONO from nonacidic soils, although it is unclear how soil that is more basic than the pKa of HONO (∼3) is capable of protonating soil nitrite to serve as an atmospheric HONO source. Here, we used a coated-wall flow tube and chemical ionization mass spectrometry (CIMS) to study the pH dependence of HONO uptake onto agricultural soil and model substrates under atmospherically relevant conditions (1 atm and 30% relative humidity). Experiments measuring the evolution of HONO from pH-adjusted surfaces treated with nitrite and potentiometric titrations of the substrates show, to our knowledge for the first time, that surface acidity rather than bulk aqueous pH determines HONO uptake and desorption efficiency on soil, in a process controlled by amphoteric aluminum and iron (hydr)oxides present. The results have important implications for predicting when soil nitrite, whether microbially derived or atmospherically deposited, will act as a net source or sink of atmospheric HONO. This process represents an unrecognized mechanism of HONO release from soil that will contribute to HONO emissions throughout the day. PMID:25512517

  4. Soil surface acidity plays a determining role in the atmospheric-terrestrial exchange of nitrous acid.

    PubMed

    Donaldson, Melissa A; Bish, David L; Raff, Jonathan D

    2014-12-30

    Nitrous acid (HONO) is an important hydroxyl (OH) radical source that is formed on both ground and aerosol surfaces in the well-mixed boundary layer. Recent studies report the release of HONO from nonacidic soils, although it is unclear how soil that is more basic than the pKa of HONO (∼ 3) is capable of protonating soil nitrite to serve as an atmospheric HONO source. Here, we used a coated-wall flow tube and chemical ionization mass spectrometry (CIMS) to study the pH dependence of HONO uptake onto agricultural soil and model substrates under atmospherically relevant conditions (1 atm and 30% relative humidity). Experiments measuring the evolution of HONO from pH-adjusted surfaces treated with nitrite and potentiometric titrations of the substrates show, to our knowledge for the first time, that surface acidity rather than bulk aqueous pH determines HONO uptake and desorption efficiency on soil, in a process controlled by amphoteric aluminum and iron (hydr)oxides present. The results have important implications for predicting when soil nitrite, whether microbially derived or atmospherically deposited, will act as a net source or sink of atmospheric HONO. This process represents an unrecognized mechanism of HONO release from soil that will contribute to HONO emissions throughout the day.

  5. Incorporation of additives into polymers

    DOEpatents

    McCleskey, T. Mark; Yates, Matthew Z.

    2003-07-29

    There has been invented a method for incorporating additives into polymers comprising: (a) forming an aqueous or alcohol-based colloidal system of the polymer; (b) emulsifying the colloidal system with a compressed fluid; and (c) contacting the colloidal polymer with the additive in the presence of the compressed fluid. The colloidal polymer can be contacted with the additive by having the additive in the compressed fluid used for emulsification or by adding the additive to the colloidal system before or after emulsification with the compressed fluid. The invention process can be carried out either as a batch process or as a continuous on-line process.

  6. Crowd Sourcing.

    PubMed

    Baum, Neil

    2016-01-01

    The Internet has contributed new words and slang to our daily vernacular. A few terms, such as tweeting, texting, sexting, blogging, and googling, have become common in most vocabularies and in many languages, and are now included in the dictionary. A new buzzword making the rounds in industry is crowd sourcing, which involves outsourcing an activity, task, or problem by sending it to people or groups outside a business or a practice. Crowd sourcing allows doctors and practices to tap the wisdom of many instead of relying only on the few members of their close-knit group. This article defines "crowd sourcing," offers examples, and explains how to get started with this approach that can increase your ability to finish a task or solve problems that you don't have the time or expertise to accomplish.

  7. ION SOURCE

    DOEpatents

    Leland, W.T.

    1960-01-01

    The ion source described essentially eliminater the problem of deposits of nonconducting materials forming on parts of the ion source by certain corrosive gases. This problem is met by removing both filament and trap from the ion chamber, spacing them apart and outside the chamber end walls, placing a focusing cylinder about the filament tip to form a thin collimated electron stream, aligning the cylinder, slits in the walls, and trap so that the electron stream does not bombard any part in the source, and heating the trap, which is bombarded by electrons, to a temperature hotter than that in the ion chamber, so that the tendency to build up a deposit caused by electron bombardment is offset by the extra heating supplied only to the trap.

  8. Neutron source

    DOEpatents

    Cason, J.L. Jr.; Shaw, C.B.

    1975-10-21

    A neutron source which is particularly useful for neutron radiography consists of a vessel containing a moderating media of relatively low moderating ratio, a flux trap including a moderating media of relatively high moderating ratio at the center of the vessel, a shell of depleted uranium dioxide surrounding the moderating media of relatively high moderating ratio, a plurality of guide tubes each containing a movable source of neutrons surrounding the flux trap, a neutron shield surrounding one part of each guide tube, and at least one collimator extending from the flux trap to the exterior of the neutron source. The shell of depleted uranium dioxide has a window provided with depleted uranium dioxide shutters for each collimator. Reflectors are provided above and below the flux trap and on the guide tubes away from the flux trap.

  9. Additive manufacturing of optical components

    NASA Astrophysics Data System (ADS)

    Heinrich, Andreas; Rank, Manuel; Maillard, Philippe; Suckow, Anne; Bauckhage, Yannick; Rößler, Patrick; Lang, Johannes; Shariff, Fatin; Pekrul, Sven

    2016-08-01

    The development of additive manufacturing methods has enlarged rapidly in recent years. Thereby, the work mainly focuses on the realization of mechanical components, but the additive manufacturing technology offers a high potential in the field of optics as well. Owing to new design possibilities, completely new solutions are possible. This article briefly reviews and compares the most important additive manufacturing methods for polymer optics. Additionally, it points out the characteristics of additive manufactured polymer optics. Thereby, surface quality is of crucial importance. In order to improve it, appropriate post-processing steps are necessary (e.g. robot polishing or coating), which will be discussed. An essential part of this paper deals with various additive manufactured optical components and their use, especially in optical systems for shape metrology (e.g. borehole sensor, tilt sensor, freeform surface sensor, fisheye lens). The examples should demonstrate the potentials and limitations of optical components produced by additive manufacturing.

  10. RADIATION SOURCES

    DOEpatents

    Brucer, M.H.

    1958-04-15

    A novel long-lived source of gamma radiation especially suitable for calibration purposes is described. The source of gamma radiation is denoted mock iodine131, which comprises a naixture of barium-133 and cesium-137. The barium and cesium are present in a barium-cesium ratio of approximately 5.7/1 to 14/1, uniformly dispersed in an ion exchange resin and a filter surrounding the resin comprised of a material of atomic number below approximately 51, and substantially 0.7 to 0.9 millimeter thick.

  11. NEUTRON SOURCE

    DOEpatents

    Reardon, W.A.; Lennox, D.H.; Nobles, R.G.

    1959-01-13

    A neutron source of the antimony--beryllium type is presented. The source is comprised of a solid mass of beryllium having a cylindrical recess extending therein and a cylinder containing antimony-124 slidably disposed within the cylindrical recess. The antimony cylinder is encased in aluminum. A berylliunn plug is removably inserted in the open end of the cylindrical recess to completely enclose the antimony cylinder in bsryllium. The plug and antimony cylinder are each provided with a stud on their upper ends to facilitate handling remotely.

  12. Evaluation of certain food additives and contaminants.

    PubMed

    2004-01-01

    This report represents the conclusions of a Joint FAO/WHO Expert Committee convened to evaluate the safety of various food additives, with a view to recommending acceptable daily intakes (ADIs) and to prepare specifications for the identity and purity of food additives. The first part of the report contains a general discussion of the principles governing the toxicological evaluation of food additives (including flavouring agents) and contaminants, assessments of intake, and the establishment and revision of specifications for food additives. A summary follows of the Committee's evaluations of toxicological and intake data on various specific food additives (alpha-amylase from Bacillus lichenformis containing a genetically engineered alpha-amylase gene from B. licheniformis, annatto extracts, curcumin, diacetyl and fatty acid esters of glycerol, D-tagatose, laccase from Myceliophthora thermophila expressed in Aspergillus oryzae, mixed xylanase, beta-glucanase enzyme preparation produced by a strain of Humicola insolens, neotame, polyvinyl alcohol, quillaia extracts and xylanase from Thermomyces lanuginosus expressed in Fusarium venenatum), flavouring agents, a nutritional source of iron (ferrous glycinate, processed with citric acid), a disinfectant for drinking-water (sodium dichloroisocyanurate) and contaminants (cadmium and methylmercury). Annexed to the report are tables summarizing the Committee's recommendations for ADIs of the food additives, recommendations on the flavouring agents considered, and tolerable intakes of the contaminants considered, changes in the status of specifications and further information requested or desired.

  13. Superluminal Sources

    NASA Astrophysics Data System (ADS)

    Vermeulen, R. C.

    1995-12-01

    Predictions for the apparent velocity statistics under simple beaming models are presented and compared to the observations. The potential applications for tests of unification models and for cosmology (source counts, measurements of the Hubble constant H_0 and the deceleration parameter q_0) are discussed. First results from a large homogeneous survey are presented. The data do not show compelling evidence for the existence of intrinsically different populations of galaxies, BL Lacertae objects, or quasars. Apparent velocities βapp in the range 1-5 h-1, where h = H_0/100 km.s-1.Mpc-1 [1 megaparsec (Mpc) = 3.09 x 1022 m], occur with roughly equal frequency; higher values, up to βapp = 10 h-1, are rather more scarce than appeared to be the case from earlier work, which evidently concentrated on sources that are not representative of the general population. The βapp distribution suggests that there might be a skewed distribution of Lorentz factors over the sample, with a peak at γ_b ≈ 2 h-1 and a tail up to at least γ_b ≈ 10 h-1. There appears to be a clearly rising upper envelope to the βapp distribution when plotted as a function of observed 5-GHz luminosity; a combination of source counts and the apparent velocity statistics in a larger sample could provide much insight into the properties of radio jet sources.

  14. Terahertz sources.

    PubMed

    Shumyatsky, Pavel; Alfano, Robert R

    2011-03-01

    We present an overview and history of terahertz (THz) sources for readers of the biomedical and optical community for applications in physics, biology, chemistry, medicine, imaging, and spectroscopy. THz low-frequency vibrational modes are involved in many biological, chemical, and solid state physical processes.

  15. Enantioselective Michael addition of water.

    PubMed

    Chen, Bi-Shuang; Resch, Verena; Otten, Linda G; Hanefeld, Ulf

    2015-02-09

    The enantioselective Michael addition using water as both nucleophile and solvent has to date proved beyond the ability of synthetic chemists. Herein, the direct, enantioselective Michael addition of water in water to prepare important β-hydroxy carbonyl compounds using whole cells of Rhodococcus strains is described. Good yields and excellent enantioselectivities were achieved with this method. Deuterium labeling studies demonstrate that a Michael hydratase catalyzes the water addition exclusively with anti-stereochemistry.

  16. Enantioselective Michael Addition of Water

    PubMed Central

    Chen, Bi-Shuang; Resch, Verena; Otten, Linda G; Hanefeld, Ulf

    2015-01-01

    The enantioselective Michael addition using water as both nucleophile and solvent has to date proved beyond the ability of synthetic chemists. Herein, the direct, enantioselective Michael addition of water in water to prepare important β-hydroxy carbonyl compounds using whole cells of Rhodococcus strains is described. Good yields and excellent enantioselectivities were achieved with this method. Deuterium labeling studies demonstrate that a Michael hydratase catalyzes the water addition exclusively with anti-stereochemistry. PMID:25529526

  17. 48 CFR 13.102 - Source list.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 1 2011-10-01 2011-10-01 false Source list. 13.102... AND CONTRACT TYPES SIMPLIFIED ACQUISITION PROCEDURES Procedures 13.102 Source list. (a) Contracting... as their primary sources of vendor information. Offices maintaining additional vendor source files...

  18. 21 CFR 640.60 - Source Plasma.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 7 2010-04-01 2010-04-01 false Source Plasma. 640.60 Section 640.60 Food and... ADDITIONAL STANDARDS FOR HUMAN BLOOD AND BLOOD PRODUCTS Source Plasma § 640.60 Source Plasma. The proper name of the product shall be Source Plasma. The product is defined as the fluid portion of human...

  19. 21 CFR 640.60 - Source Plasma.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 7 2012-04-01 2012-04-01 false Source Plasma. 640.60 Section 640.60 Food and... ADDITIONAL STANDARDS FOR HUMAN BLOOD AND BLOOD PRODUCTS Source Plasma § 640.60 Source Plasma. The proper name of the product shall be Source Plasma. The product is defined as the fluid portion of human...

  20. 21 CFR 640.60 - Source Plasma.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 7 2013-04-01 2013-04-01 false Source Plasma. 640.60 Section 640.60 Food and... ADDITIONAL STANDARDS FOR HUMAN BLOOD AND BLOOD PRODUCTS Source Plasma § 640.60 Source Plasma. The proper name of the product shall be Source Plasma. The product is defined as the fluid portion of human...

  1. 21 CFR 640.60 - Source Plasma.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 7 2014-04-01 2014-04-01 false Source Plasma. 640.60 Section 640.60 Food and... ADDITIONAL STANDARDS FOR HUMAN BLOOD AND BLOOD PRODUCTS Source Plasma § 640.60 Source Plasma. The proper name of the product shall be Source Plasma. The product is defined as the fluid portion of human...

  2. 48 CFR 13.102 - Source list.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... as their primary sources of vendor information. Offices maintaining additional vendor source files or... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Source list. 13.102... AND CONTRACT TYPES SIMPLIFIED ACQUISITION PROCEDURES Procedures 13.102 Source list. (a)...

  3. Color Addition and Subtraction Apps

    ERIC Educational Resources Information Center

    Ruiz, Frances; Ruiz, Michael J.

    2015-01-01

    Color addition and subtraction apps in HTML5 have been developed for students as an online hands-on experience so that they can more easily master principles introduced through traditional classroom demonstrations. The evolution of the additive RGB color model is traced through the early IBM color adapters so that students can proceed step by step…

  4. Additive Effects on Asymmetric Catalysis.

    PubMed

    Hong, Liang; Sun, Wangsheng; Yang, Dongxu; Li, Guofeng; Wang, Rui

    2016-03-23

    This review highlights a number of additives that can be used to make asymmetric reactions perfect. Without changing other reaction conditions, simply adding additives can lead to improved asymmetric catalysis, such as reduced reaction time, improved yield, or/and increased selectivity.

  5. ION SOURCE

    DOEpatents

    Brobeck, W.M.

    1959-04-14

    This patent deals with calutrons and more particularly to an arrangement therein whereby charged bottles in a calutron source unit may be replaced without admitting atmospheric air to the calutron vacuum chamber. As described, an ion unit is disposed within a vacuum tank and has a reservoir open toward a wall of the tank. A spike projects from thc source into the reservoir. When a charge bottle is placed in the reservoir, the spike breaks a frangible seal on the bottle. After the contents of the bottle are expended the bottle may be withdrawn and replaced with another charge bottle by a varuum lock arrangement in conjunction with an arm for manipulating the bottle.

  6. Ion source

    DOEpatents

    Brobeck, W. M.

    1959-04-14

    This patent deals with calutrons and more particularly to an arrangement therein whereby charged bottles in a calutron source unit may be replaced without admitting atmospheric air to the calutron vacuum chamber. As described, an ion unit is disposed within a vacuum tank and has a reservoir open toward a wall of the tank. A spike projects from the source into the reservoir. When a charge bottle is placed in the reservoir, the spike breaks a frangible seal on the bottle. After the contents of the bottle are expended the bottle may be withdrawn and replaced with another charge bottle by a vacuum lock arrangement in conjunction with an arm for manipulating the bottle.

  7. ION SOURCE

    DOEpatents

    Blue, C.W.; Luce, J.S.

    1960-07-19

    An ion source is described and comprises an arc discharge parallel to the direction of and inside of a magnetic field. an accelerating electrode surrounding substantially all of the discharge except for ion exit apertures, and means for establishing an electric field between that electrode and the arc discharge. the electric field being oriented at an acute angle to the magnetic field. Ions are drawn through the exit apertures in the accelrating electrcde in a direction substantially divergent to the direction of the magnetic field and so will travel in a spiral orbit along the magnetic field such that the ions will not strike the source at any point in their orbit within the magnetic field.

  8. ION SOURCE

    DOEpatents

    Bell, W.A. Jr.; Love, L.O.; Prater, W.K.

    1958-01-28

    An ion source is presented capable of producing ions of elements which vaporize only at exceedingly high temperatures, i.e.,--1500 degrees to 3000 deg C. The ion source utilizes beams of electrons focused into a first chamber housing the material to be ionized to heat the material and thereby cause it to vaporize. An adjacent second chamber receives the vaporized material through an interconnecting passage, and ionization of the vaporized material occurs in this chamber. The ionization action is produced by an arc discharge sustained between a second clectron emitting filament and the walls of the chamber which are at different potentials. The resultant ionized material egresses from a passageway in the second chamber. Using this device, materials which in the past could not be processed in mass spectometers may be satisfactorily ionized for such applications.

  9. Embedding Sensors During Additive Manufacturing

    SciTech Connect

    Sbriglia, Lexey Raylene

    2015-08-10

    This PowerPoint presentation had the following headings: Fused deposition modeling (FDM); Open source 3D printing; Objectives; Vibration analysis; Equipment; Design; Material choices; Failure causes, such as tension, bubbling; Potential solutions; Simulations; Embedding the sensors; LabView programming; Alternate data acquisition; Problem and proposed solution; and, Conclusions

  10. Color Addition and Subtraction Apps

    NASA Astrophysics Data System (ADS)

    Ruiz, Frances; Ruiz, Michael J.

    2015-10-01

    Color addition and subtraction apps in HTML5 have been developed for students as an online hands-on experience so that they can more easily master principles introduced through traditional classroom demonstrations. The evolution of the additive RGB color model is traced through the early IBM color adapters so that students can proceed step by step in understanding mathematical representations of RGB color. Finally, color addition and subtraction are presented for the X11 colors from web design to illustrate yet another real-life application of color mixing.

  11. [Trends in the utilization of food additives].

    PubMed

    Szűcs, Viktória; Bánáti, Diána

    2013-11-17

    The frequent media reports on food additives weakened consumers' trust in food producers and food control authorities as well. Furthermore, consumers' uncertainty is also raised by the fact that they obtain their information from inadequate, mistrustful sources and, therefore, consumers might avoid the consumption of certain foodstuffs. While food producers may react by replacing artificial components by natural ones, they try to emphasize the favourable characteristics of their products. The authors describe the main trends and efforts related to food additives. On the basis of the overview it can be concluded that - besides taking into consideration consumers' needs - product development and research directions are promising. Food producers' efforts may help to restore consumer confidence and trust and they may help them to have informed choice.

  12. Adverse reactions to drug additives.

    PubMed

    Simon, R A

    1984-10-01

    There is a long list of additives used by the pharmaceutical industry. Most of the agents used have not been implicated in hypersensitivity reactions. Among those that have, only reactions to parabens and sulfites have been well established. Parabens have been shown to be responsible for rare immunoglobulin E-mediated reactions that occur after the use of local anesthetics. Sulfites, which are present in many drugs, including agents commonly used to treat asthma, have been shown to provoke severe asthmatic attacks in sensitive individuals. Recent studies indicate that additives do not play a significant role in "hyperactivity." The role of additives in urticaria is not well established and therefore the incidence of adverse reactions in this patient population is simply not known. In double-blind, placebo-controlled studies, reactions to tartrazine or additives other than sulfites, if they occur at all, are indeed quite rare for the asthmatic population, even for the aspirin-sensitive subpopulation.

  13. Radiation Therapy: Additional Treatment Options

    MedlinePlus

    ... SNIPEND SNIPSTART Find A Radiation Oncologist SNIPEND Additional Treatment Options SNIPSTART A A SNIPEND Chemotherapy Medicines prescribed ... such as antibodies, to fight cancer. Novel Targeted Therapies Cancer doctors now know much more about how ...

  14. Calculators and Computers: Graphical Addition.

    ERIC Educational Resources Information Center

    Spero, Samuel W.

    1978-01-01

    A computer program is presented that generates problem sets involving sketching graphs of trigonometric functions using graphical addition. The students use calculators to sketch the graphs and a computer solution is used to check it. (MP)

  15. Uptake of gas phase nitrous acid onto boundary layer soil surfaces.

    PubMed

    Donaldson, Melissa A; Berke, Andrew E; Raff, Jonathan D

    2014-01-01

    Nitrous acid (HONO) is an important OH radical source that is formed on both ground and aerosol surfaces in the well-mixed boundary layer. Large uncertainties remain in quantifying HONO sinks and determining the mechanism of HONO uptake onto surfaces. We report here the first laboratory determination of HONO uptake coefficients onto actual soil under atmospheric conditions using a coated-wall flow tube coupled to a highly sensitive chemical ionization mass spectrometer (CIMS). Uptake coefficients for HONO decrease with increasing RH from (2.5 ± 0.4) × 10(-4) at 0% RH to (1.1 ± 0.4) × 10(-5) at 80% RH. A kinetics model of competitive adsorption of HONO and water onto the particle surfaces fits the dependence of the HONO uptake coefficients on the initial HONO concentration and relative humidity. However, a multiphase resistor model based on the physical and chemical processes affecting HONO uptake is more flexible as it accounts for the pH dependence of HONO uptake and bulk diffusion in the soil matrix. Fourier transform infrared (FTIR) spectrometry and cavity-enhanced absorption spectroscopy (CEAS) studies indicate that NO and N2O (16% and 13% yield, respectively) rather than NO2 are the predominant gas phase products, while NO2(-) and NO3(-) were detected on the surface post-exposure. Results are compared to uptake coefficients inferred from models and field measurements, and the atmospheric implications are discussed.

  16. Food additives and preschool children.

    PubMed

    Martyn, Danika M; McNulty, Breige A; Nugent, Anne P; Gibney, Michael J

    2013-02-01

    Food additives have been used throughout history to perform specific functions in foods. A comprehensive framework of legislation is in place within Europe to control the use of additives in the food supply and ensure they pose no risk to human health. Further to this, exposure assessments are regularly carried out to monitor population intakes and verify that intakes are not above acceptable levels (acceptable daily intakes). Young children may have a higher dietary exposure to chemicals than adults due to a combination of rapid growth rates and distinct food intake patterns. For this reason, exposure assessments are particularly important in this age group. The paper will review the use of additives and exposure assessment methods and examine factors that affect dietary exposure by young children. One of the most widely investigated unfavourable health effects associated with food additive intake in preschool-aged children are suggested adverse behavioural effects. Research that has examined this relationship has reported a variety of responses, with many noting an increase in hyperactivity as reported by parents but not when assessed using objective examiners. This review has examined the experimental approaches used in such studies and suggests that efforts are needed to standardise objective methods of measuring behaviour in preschool children. Further to this, a more holistic approach to examining food additive intakes by preschool children is advisable, where overall exposure is considered rather than focusing solely on behavioural effects and possibly examining intakes of food additives other than food colours.

  17. Evaluation of certain food additives.

    PubMed

    2015-01-01

    This report represents the conclusions of a Joint FAO/WHO Expert Committee convened to evaluate the safety of various food additives, including flavouring agents, and to prepare specifications for identity and purity. The first part of the report contains a general discussion of the principles governing the toxicological evaluation of and assessment of dietary exposure to food additives, including flavouring agents. A summary follows of the Committee's evaluations of technical, toxicological and dietary exposure data for eight food additives (Benzoe tonkinensis; carrageenan; citric and fatty acid esters of glycerol; gardenia yellow; lutein esters from Tagetes erecta; octenyl succinic acid-modified gum arabic; octenyl succinic acid-modified starch; paprika extract; and pectin) and eight groups of flavouring agents (aliphatic and alicyclic hydrocarbons; aliphatic and aromatic ethers; ionones and structurally related substances; miscellaneous nitrogen-containing substances; monocyclic and bicyclic secondary alcohols, ketones and related esters; phenol and phenol derivatives; phenyl-substituted aliphatic alcohols and related aldehydes and esters; and sulfur-containing heterocyclic compounds). Specifications for the following food additives were revised: citric acid; gellan gum; polyoxyethylene (20) sorbitan monostearate; potassium aluminium silicate; and Quillaia extract (Type 2). Annexed to the report are tables summarizing the Committee's recommendations for dietary exposures to and toxicological evaluations of all of the food additives and flavouring agents considered at this meeting.

  18. [INVITED] Lasers in additive manufacturing

    NASA Astrophysics Data System (ADS)

    Pinkerton, Andrew J.

    2016-04-01

    Additive manufacturing is a topic of considerable ongoing interest, with forecasts predicting it to have major impact on industry in the future. This paper focusses on the current status and potential future development of the technology, with particular reference to the role of lasers within it. It begins by making clear the types and roles of lasers in the different categories of additive manufacturing. This is followed by concise reviews of the economic benefits and disadvantages of the technology, current state of the market and use of additive manufacturing in different industries. Details of these fields are referenced rather than expanded in detail. The paper continues, focusing on current indicators to the future of additive manufacturing. Barriers to its development, trends and opportunities in major industrial sectors, and wider opportunities for its development are covered. Evidence indicates that additive manufacturing may not become the dominant manufacturing technology in all industries, but represents an excellent opportunity for lasers to increase their influence in manufacturing as a whole.

  19. Additive manufacturing of hybrid circuits

    SciTech Connect

    Bell, Nelson S.; Sarobol, Pylin; Cook, Adam; Clem, Paul G.; Keicher, David M.; Hirschfeld, Deidre; Hall, Aaron Christopher

    2016-03-26

    There is a rising interest in developing functional electronics using additively manufactured components. Considerations in materials selection and pathways to forming hybrid circuits and devices must demonstrate useful electronic function; must enable integration; and must complement the complex shape, low cost, high volume, and high functionality of structural but generally electronically passive additively manufactured components. This article reviews several emerging technologies being used in industry and research/development to provide integration advantages of fabricating multilayer hybrid circuits or devices. First, we review a maskless, noncontact, direct write (DW) technology that excels in the deposition of metallic colloid inks for electrical interconnects. Second, we review a complementary technology, aerosol deposition (AD), which excels in the deposition of metallic and ceramic powder as consolidated, thick conformal coatings and is additionally patternable through masking. As a result, we show examples of hybrid circuits/devices integrated beyond 2-D planes, using combinations of DW or AD processes and conventional, established processes.

  20. RADIATION SOURCE

    DOEpatents

    Gow, J.D.

    1961-06-27

    An improved version of a crossed electric and magnetic field plasma producing and containing device of the general character disclosed in U. S. Patent No. 2,967,943 is described. This device employs an annular magnet encased within an anode and a pair of cathodes respectively coaxially spaced from the opposite ends of the anode to establish crossed field electron trapping regions adjacent the ends of the anode. The trapping regions are communicably connected through the throat of the anode and the electric field negatively increases in opposite axial directions from the center of the throat. Electrons are trapped within the two trapping regions and throat to serve as a source of intense ionization to gas introduced thereto, the ions in copious quantities being attracted to the cathodes to bombard neutron productive targets dlsposed - thereat.

  1. Tougher Addition Polyimides Containing Siloxane

    NASA Technical Reports Server (NTRS)

    St. Clair, T. L.; Maudgal, S.

    1986-01-01

    Laminates show increased impact resistances and other desirable mechanical properties. Bismaleamic acid extended by reaction of diaminosiloxane with maleic anhydride in 1:1 molar ratio, followed by reaction with half this molar ratio of aromatic dianhydride. Bismaleamic acid also extended by reaction of diaminosiloxane with maleic anhydride in 1:2 molar ratio, followed by reaction with half this molar ratio of aromatic diamine (Michael-addition reaction). Impact resistances improved over those of unmodified bismaleimide, showing significant increase in toughness. Aromatic addition polyimides developed as both matrix and adhesive resins for applications on future aircraft and spacecraft.

  2. The Additive Property of Energy.

    ERIC Educational Resources Information Center

    Tsaoussis, Dimitris S.

    1995-01-01

    Presents exercises that analyze the additive property of energy. Concludes that if a body has more than one component of energy depending on the same physical quantity, the body's total energy will be the algebraic sum of the components if a linear relationship exists between the energy components and that physical quantity. (JRH)

  3. Tetrasulfide extreme pressure lubricant additives

    SciTech Connect

    Gast, L.E.; Kenney, H.E.; Schwab, A.W.

    1980-08-19

    A novel class of compounds has been prepared comprising the tetrasulfides of /sup 18/C hydrocarbons, /sup 18/C fatty acids, and /sup 18/C fatty and alkyl and triglyceride esters. These tetrasulfides are useful as extreme pressure lubricant additives and show potential as replacements for sulfurized sperm whale oil.

  4. Out of bounds additive manufacturing

    SciTech Connect

    Holshouser, Chris; Newell, Clint; Palas, Sid; Love, Lonnie J.; Kunc, Vlastimil; Lind, Randall F.; Lloyd, Peter D.; Rowe, John C.; Blue, Craig A.; Duty, Chad E.; Peter, William H.; Dehoff, Ryan R.

    2013-03-01

    Lockheed Martin and Oak Ridge National Laboratory are working on an additive manufacturing system capable of manufacturing components measured not in terms of inches or feet, but multiple yards in all dimensions with the potential to manufacture parts that are completely unbounded in size.

  5. Evaluation of certain food additives.

    PubMed

    2012-01-01

    This report represents the conclusions of a Joint FAO/WHO Expert Committee convened to evaluate the safety of various food additives, including flavouring agents, with a view to concluding as to safety concerns and to preparing specifications for identity and purity. The first part of the report contains a general discussion of the principles governing the toxicological evaluation of and assessment of dietary exposure to food additives, including flavouring agents. A summary follows of the Committee's evaluations of technical, toxicological and dietary exposure data for five food additives (magnesium dihydrogen diphosphate; mineral oil (medium and low viscosity) classes II and III; 3-phytase from Aspergillus niger expressed in Aspergillus niger; serine protease (chymotrypsin) from Nocardiopsis prasina expressed in Bacillus licheniformis; and serine protease (trypsin) from Fusarium oxysporum expressed in Fusarium venenatum) and 16 groups of flavouring agents (aliphatic and aromatic amines and amides; aliphatic and aromatic ethers; aliphatic hydrocarbons, alcohols, aldehydes, ketones, carboxylic acids and related esters, sulfides, disulfides and ethers containing furan substitution; aliphatic linear alpha,beta-unsaturated aldehydes, acids and related alcohols, acetals and esters; amino acids and related substances; epoxides; furfuryl alcohol and related substances; linear and branched-chain aliphatic, unsaturated, unconjugated alcohols, aldehydes, acids and related esters; miscellaneous nitrogen-containing substances; phenol and phenol derivatives; pyrazine derivatives; pyridine, pyrrole and quinoline derivatives; saturated aliphatic acyclic branched-chain primary alcohols, aldehydes and acids; simple aliphatic and aromatic sulfides and thiols; sulfur-containing heterocyclic compounds; and sulfur-substituted furan derivatives). Specifications for the following food additives were revised: ethyl cellulose, mineral oil (medium viscosity), modified starches and titanium

  6. Food additives and contaminants. An update.

    PubMed

    Newberne, P M; Conner, M W

    1986-10-15

    Food additives continue to be a source of benefits to the consuming public but there are also perceived risks. Concern for the latter in the last decade has produced a society afflicted with cancer phobia. The intentional additives including sugars, salt, corn syrup, and dextrose make up 90% of the direct additives. These, along with a limited number of familiar items make up a large proportion of the remainder of the additives. Such common ingredients as nitrates and nitrites, solanine, cyanogenetic compounds, arsenic, etc., are unavoidably consumed in the diet and with little if any evidence for public health consequences. Major concern on the part of the public in recent years has been focused on man-made chemicals which are intentionally added to foods to enhance flavors and acceptability, nutrient value, shelf life and increased availability. These include food colors, nonnutritive and low-nutrient sweeteners, (saccharin, cyclamate, aspartame); antioxidants; and nitrites. Contaminants, sometimes incorrectly included in lists of food additives, present the greatest potential threat to public health. Such contaminants as mycotoxins, nitrosamines, polychlorinated biphenyls (PCBs), pesticides, among others, provide a continuing challenge to our regulatory agencies and to public health authorities. Evidence to date indicate that these responsible for food safety are doing an admirable job, and as a society, our food supply has never been better, or safer, and, as a population, we have never been healthier. Aside from contaminants, major concerns relate to an excess of good food and to obesity. These comments should not be taken to infer that we should relax our concern and surveillance; instead more concern and surveillance should be exerted toward those uncontrolled substances such as natural plant products and alleged natural nutrients, roots, herbs, etc., which are given much credit for positive health effects, without meeting the high standards of our

  7. Radiation source

    DOEpatents

    Thode, Lester E.

    1981-01-01

    A device and method for relativistic electron beam heating of a high-density plasma in a small localized region. A relativistic electron beam generator or accelerator produces a high-voltage electron beam which propagates along a vacuum drift tube and is modulated to initiate electron bunching within the beam. The beam is then directed through a low-density gas chamber which provides isolation between the vacuum modulator and the relativistic electron beam target. The relativistic beam is then applied to a high-density target plasma which typically comprises DT, DD, or similar thermonuclear gas at a density of 10.sup.17 to 10.sup.20 electrons per cubic centimeter. The target gas is ionized prior to application of the relativistic electron beam by means of a laser or other preionization source to form a plasma. Utilizing a relativistic electron beam with an individual particle energy exceeding 3 MeV, classical scattering by relativistic electrons passing through isolation foils is negligible. As a result, relativistic streaming instabilities are initiated within the high-density target plasma causing the relativistic electron beam to efficiently deposit its energy into a small localized region of the high-density plasma target.

  8. The Frontiers of Additive Manufacturing

    SciTech Connect

    Grote, Christopher John

    2016-03-03

    Additive manufacturing, more commonly known as 3-D printing, has become a ubiquitous tool in science for its precise control over mechanical design. For additive manufacturing to work, a 3-D structure is split into thin 2D slices, and then different physical properties, such as photo-polymerization or melting, are used to grow the sequential layers. The level of control allows not only for devices to be made with a variety of materials: e.g. plastics, metals, and quantum dots, but to also have finely controlled structures leading to other novel properties. While 3-D printing is widely used by hobbyists for making models, it also has industrial applications in structural engineering, biological tissue scaffolding, customized electric circuitry, fuel cells, security, and more.

  9. Decontamination formulation with sorbent additive

    DOEpatents

    Tucker; Mark D. , Comstock; Robert H.

    2007-10-16

    A decontamination formulation and method of making that neutralizes the adverse health effects of both chemical and biological compounds, especially chemical warfare (CW) and biological warfare (BW) agents, and toxic industrial chemicals. The formulation provides solubilizing compounds that serve to effectively render the chemical and biological compounds, particularly CW and BW compounds, susceptible to attack, and at least one reactive compound that serves to attack (and detoxify or kill) the compound. The formulation includes at least one solubilizing agent, a reactive compound, a bleaching activator, a sorbent additive, and water. The highly adsorbent, water-soluble sorbent additive (e.g., sorbitol or mannitol) is used to "dry out" one or more liquid ingredients, such as the liquid bleaching activator (e.g., propylene glycol diacetate or glycerol diacetate) and convert the activator into a dry, free-flowing powder that has an extended shelf life, and is more convenient to handle and mix in the field.

  10. Additive Manufacturing Integrated Energy Demonstration

    SciTech Connect

    Jackson, Roderick; Lee, Brian; Love, Lonnie; Mabe, Gavin; Keller, Martin; Curran, Scott; Chinthavali, Madhu; Green, Johney; Sawyer, Karma; Enquist, Phil

    2016-02-05

    Meet AMIE - the Additive Manufacturing Integrated Energy demonstration project. Led by Oak Ridge National Laboratory and many industry partners, the AMIE project changes the way we think about generating, storing, and using electrical power. AMIE uses an integrated energy system that shares energy between a building and a vehicle. And, utilizing advanced manufacturing and rapid innovation, it only took one year from concept to launch.

  11. Robust stability under additive perturbations

    NASA Technical Reports Server (NTRS)

    Bhaya, A.; Desoer, C. A.

    1985-01-01

    A MIMO linear time-invariant feedback system 1S(P,C) is considered which is assumed to be U-stable. The plant P is subjected to an additive perturbation Delta P which is proper but not necessarily stable. It is proved that the perturbed system is U-stable if and only if Delta P(I + Q x Delta P) exp -1 is U-stable.

  12. Additive Manufacturing Integrated Energy Demonstration

    ScienceCinema

    Jackson, Roderick; Lee, Brian; Love, Lonnie; Mabe, Gavin; Keller, Martin; Curran, Scott; Chinthavali, Madhu; Green, Johney; Sawyer, Karma; Enquist, Phil

    2016-07-12

    Meet AMIE - the Additive Manufacturing Integrated Energy demonstration project. Led by Oak Ridge National Laboratory and many industry partners, the AMIE project changes the way we think about generating, storing, and using electrical power. AMIE uses an integrated energy system that shares energy between a building and a vehicle. And, utilizing advanced manufacturing and rapid innovation, it only took one year from concept to launch.

  13. Nanoengineered Additives for Active Coatings

    DTIC Science & Technology

    2007-04-01

    commercial ad bial activ component from the coating, leading to eventual depletion of the film. Small TPU samples were evaluated using a Kirby - Bauer ...7 Table 5. Summary of 24-hr ASTM E 2180 tests with 1 weight-percent additive in PUr (solvent dispersible) based on 6-log loading of...Noveon X-1150). The ASTM E 2180 test is run in triplicate (Note that alternative ro 1° amines) was suspended in dry tetrahydrofuran (THF) (150 mL) in

  14. Reversible Oxidative Addition at Carbon.

    PubMed

    Eichhorn, Antonius F; Fuchs, Sonja; Flock, Marco; Marder, Todd B; Radius, Udo

    2017-04-07

    The reactivity of N-heterocyclic carbenes (NHCs) and cyclic alkyl amino carbenes (cAACs) with arylboronate esters is reported. The reaction with NHCs leads to the reversible formation of thermally stable Lewis acid/base adducts Ar-B(OR)2 ⋅NHC (Add1-Add6). Addition of cAAC(Me) to the catecholboronate esters 4-R-C6 H4 -Bcat (R=Me, OMe) also afforded the adducts 4-R-C6 H4 Bcat⋅cAAC(Me) (Add7, R=Me and Add8, R=OMe), which react further at room temperature to give the cAAC(Me) ring-expanded products RER1 and RER2. The boronate esters Ar-B(OR)2 of pinacol, neopentylglycol, and ethyleneglycol react with cAAC at RT via reversible B-C oxidative addition to the carbene carbon atom to afford cAAC(Me) (B{OR}2 )(Ar) (BCA1-BCA6). NMR studies of cAAC(Me) (Bneop)(4-Me-C6 H4 ) (BCA4) demonstrate the reversible nature of this oxidative addition process.

  15. Additive manufacturing of hybrid circuits

    DOE PAGES

    Bell, Nelson S.; Sarobol, Pylin; Cook, Adam; ...

    2016-03-26

    There is a rising interest in developing functional electronics using additively manufactured components. Considerations in materials selection and pathways to forming hybrid circuits and devices must demonstrate useful electronic function; must enable integration; and must complement the complex shape, low cost, high volume, and high functionality of structural but generally electronically passive additively manufactured components. This article reviews several emerging technologies being used in industry and research/development to provide integration advantages of fabricating multilayer hybrid circuits or devices. First, we review a maskless, noncontact, direct write (DW) technology that excels in the deposition of metallic colloid inks for electrical interconnects.more » Second, we review a complementary technology, aerosol deposition (AD), which excels in the deposition of metallic and ceramic powder as consolidated, thick conformal coatings and is additionally patternable through masking. As a result, we show examples of hybrid circuits/devices integrated beyond 2-D planes, using combinations of DW or AD processes and conventional, established processes.« less

  16. Fire-Retardant Polymeric Additives

    NASA Technical Reports Server (NTRS)

    Williams, Martha K.; Smith, Trent M.

    2011-01-01

    Polyhydroxyamide (PHA) and polymethoxyamide (PMeOA) are fire-retardant (FR) thermoplastic polymers and have been found to be useful as an additive for imparting fire retardant properties to other compatible, thermoplastic polymers (including some elastomers). Examples of compatible flammable polymers include nylons, polyesters, and acrylics. Unlike most prior additives, PHA and PMeOA do not appreciably degrade the mechanical properties of the matrix polymer; indeed, in some cases, mechanical properties are enhanced. Also, unlike some prior additives, PHA and PMeOA do not decompose into large amounts of corrosive or toxic compounds during combustion and can be processed at elevated temperatures. PMeOA derivative formulations were synthesized and used as an FR additive in the fabrication of polyamide (PA) and polystyrene (PS) composites with notable reduction (>30 percent for PS) in peak heat release rates compared to the neat polymer as measured by a Cone Calorimeter (ASTM E1354). Synergistic effects were noted with nanosilica composites. These nanosilica composites had more than 50-percent reduction in peak heat release rates. In a typical application, a flammable thermoplastic, thermoplastic blend, or elastomer that one seeks to render flame-retardant is first dry-mixed with PHA or PMeOA or derivative thereof. The proportion of PHA or PMeOA or derivative in the mixture is typically chosen to lie between 1 and 20 weight percent. The dry blend can then be melt-extruded. The extruded polymer blend can further be extruded and/or molded into fibers, pipes, or any other of a variety of objects that may be required to be fire-retardant. The physical and chemical mechanisms which impart flame retardancy of the additive include inhibiting free-radical oxidation in the vapor phase, preventing vaporization of fuel (the polymer), and cooling through the formation of chemical bonds in either the vapor or the condensed phase. Under thermal stress, the cyclic hydroxyl/ methoxy

  17. Evaluation of certain food additives.

    PubMed

    2009-01-01

    This report represents the conclusions of a Joint FAO/WHO Expert Committee convened to evaluate the safety of various food additives, including flavouring agents, with a view to recommending acceptable daily intakes (ADIs) and to preparing specifications for identity and purity. The first part of the report contains a general discussion of the principles governing the toxicological evaluation and assessment of intake of food additives (in particular, flavouring agents). A summary follows of the Committee's evaluations of technical, toxicological and intake data for certain food additives (asparaginase from Aspergillus niger expressed in A. niger, calcium lignosulfonate (40-65), ethyl lauroyl arginate, paprika extract, phospholipase C expressed in Pichia pastoris, phytosterols, phytostanols and their esters, polydimethylsiloxane, steviol glycosides and sulfites [assessment of dietary exposure]) and 10 groups of related flavouring agents (aliphatic branched-chain saturated and unsaturated alcohols, aldehydes, acids and related esters; aliphatic linear alpha,beta-unsaturated aldehydes, acids and related alcohols, acetals and esters; aliphatic secondary alcohols, ketones and related esters; alkoxy-substituted allylbenzenes present in foods and essential oils and used as flavouring agents; esters of aliphatic acyclic primary alcohols with aliphatic linear saturated carboxylic acids; furan-substituted aliphatic hydrocarbons, alcohols, aldehydes, ketones, carboxylic acids and related esters, sulfides, disulfides and ethers; miscellaneous nitrogen-containing substances; monocyclic and bicyclic secondary alcohols, ketones and related esters; hydroxy- and alkoxy-substituted benzyl derivatives; and substances structurally related to menthol). Specifications for the following food additives were revised: canthaxanthin; carob bean gum and carob bean gum (clarified); chlorophyllin copper complexes, sodium and potassium salts; Fast Green FCF; guar gum and guar gum (clarified

  18. Hoono Isomerization to HONO_2 Involving Conical Intersections

    NASA Astrophysics Data System (ADS)

    Kumar, T. J. Dhilip; Stanton, John F.; Barker, John R.

    2009-06-01

    The important atmospheric reactions HO_2 + NO and OH + NO_2 lead to formation and dissociation of the cis- and trans- isomers of the HOONO complex. In the present work, the global HNO_3 potential energy surface (PES) is being studied by using high-level ab initio electronic structure methods. This PES and others in the same class have been studied previously by others. In the F + NO_2 reaction system, UCCSD(T) calculations showed that FONO isomerizes to FNO_2 through a tight transition state involving a two-state avoided curve crossing. A similar mechanism has been invoked for HOONO, which is isoelectronic with FONO. CASSCF multi-configurational calculations on the CH_3O + NO_2 reaction located a conical intersection near where single-configurational DFT methods predict an intrinsic energy barrier; the barrier was suggested to be an artifact. In present work, the global HNO_3 PES is being investigated by both the UCCSD(T) and CASSCF methods in order to study the influence of low-lying excited electronic states on the ground state PES and reaction dynamics. L. P. Olsen, M. D. Bartberger and K. N. Houk, J. Am. Chem. Soc., 125, 3999 (2003) G. B. Ellison, J. M. Herbert, A. B. McCoy, J. F. Stanton and P. G. Szalay, J. Phys. Chem. A 108, 7639 (2004). J. F. Arenas, F. J. Avila, J. C. Otero, D. Peláez and J. Soto, J. Phys. Chem. A 112, 249 (2008).

  19. The Mozart Effect: Additional Data.

    PubMed

    Hughes, John R.

    2002-04-01

    After the review of the Mozart effect was published in this journal (Hughes JR. Epilepsy Behav 2001;2:369-417), additional data from the music of Haydn and Liszt have been analyzed that may account for the decrease in seizure activity originally reported during Mozart music. Even with these added data Mozart music continued to score significantly higher than the selections from the other six composers in one of the important characteristics of this music, namely, the repetition of the melody. However Haydn's values were second highest among Mozart, J. S. Bach, Wagner, Beethoven, Chopin, and Liszt.

  20. Water based drilling mud additive

    SciTech Connect

    McCrary, J.L.

    1983-12-13

    A water based fluid additive useful in drilling mud used during drilling of an oil or gas well is disclosed, produced by reacting water at temperatures between 210/sup 0/-280/sup 0/ F. with a mixture comprising in percent by weight: gilsonite 25-30%, tannin 7-15%, lignite 25-35%, sulfonating compound 15-25%, water soluble base compound 5-15%, methylene-yielding compound 1-5%, and then removing substantially all of the remaining water to produce a dried product.

  1. Metal Additive Manufacturing: A Review

    NASA Astrophysics Data System (ADS)

    Frazier, William E.

    2014-06-01

    This paper reviews the state-of-the-art of an important, rapidly emerging, manufacturing technology that is alternatively called additive manufacturing (AM), direct digital manufacturing, free form fabrication, or 3D printing, etc. A broad contextual overview of metallic AM is provided. AM has the potential to revolutionize the global parts manufacturing and logistics landscape. It enables distributed manufacturing and the productions of parts-on-demand while offering the potential to reduce cost, energy consumption, and carbon footprint. This paper explores the material science, processes, and business consideration associated with achieving these performance gains. It is concluded that a paradigm shift is required in order to fully exploit AM potential.

  2. Theatre fleet's vital additional capacity.

    PubMed

    2012-11-01

    Vanguard Healthcare's fleet of mobile surgical facilities has been deployed to healthcare sites throughout Europe and beyond for over a decade, providing vital additional clinical capacity when existing buildings are refurbished or upgraded, in the event of flood or fire, or simply to help hospitals cater for rising demand. It is a combination of careful planning, teamwork, and the specialist expertise of Vanguard's personnel--many with a clinical background--that ensures not only each unit's successful installation, but equally its subsequent running, servicing, and maintenance, the company explains.

  3. Shale JP-4 Additive Evaluation

    DTIC Science & Technology

    1986-10-01

    8217. •% . , ’ ,,,r ,% . -- - ,.-. ’ ’ 4,w% %’. " - ,’ . . . * ’, .* . TABLE OF CONTENTS .4q ,4 . * SECTION PAGE I. INTRODUCTION 1 II. TEST PARAMETERS 2 1...42 PRECEDING PAGE BLANK TABLE OF CONTENTS (CON’T) SECT ION PAGE V. CONCLUSIONS 44 REFERENCES 46 APPENDIX A Drum to Test Sample Relationship 47 APPENDIX...B.O.C.L.E. Results 40 vii LIST OF TABLES TABLE PAGE 1 Antioxidants 3 2 Raw Shale/Petroleum Fuel Properties 10 3 Drum Sample Additive Content 13 4

  4. Determination of nitrous acid emission factors from a gasoline vehicle using a chassis dynamometer combined with incoherent broadband cavity-enhanced absorption spectroscopy.

    PubMed

    Nakashima, Yoshihiro; Kajii, Yoshizumi

    2017-01-01

    Nitrous acid (HONO) is a well-known source of hydroxyl radicals in the troposphere. Vehicle exhaust is considered to be one of the primary emission sources of HONO. In this study, measurements of HONO in gasoline vehicle exhaust were carried out using a chassis dynamometer combined with incoherent broadband cavity-enhanced absorption spectroscopy. When catalysts were warm, concentrations of HONO were higher than those prior to catalysts warming. Other species, such as CO, and total hydrocarbons (THCs), showed the opposite pattern. There were no correlations evident between HONO and other trace species concentrations immediately after emission. The HONO/NOx ratio, a good proxy for the formation of HONO in atmosphere, ranged from 1.1 to 6.8×10(-3), which was consistent with previous studies. HONO emission factors (EFs) were calculated to be 0.01-3.6mgkg(-1) fuel, which was different from the vehicle's specifications and those reported under different driving cycles. Annual HONO emissions in Japan were estimated using the calculated EFs and other statistical data.

  5. High Flow Addition Curing Polyimides

    NASA Technical Reports Server (NTRS)

    Chuang, Kathy C.; Vannucci, Raymond D.; Ansari, Irfan; Cerny, Lawrence L.; Scheiman, Daniel A.

    1994-01-01

    A new series of high flow PMR-type addition curing polyimides was developed, which employed the substitution of 2,2'-bis (trifluoromethyl) -4,4'-diaminobiphenyl (BTDB) for p-phenylenediamine (p -PDA) in a PMR-IL formulation. These thermoset polyimides, designated as 12F resins, were prepared from BTDB and the dimethyl ester of 4,4'- (hexafluo- roisopropylidene) -diphthalic acid (HFDE) with either nadic ester (NE) or p-aminostyrene (PAS) as the endcaps for addition curing. The 12F prepolymers displayed lower melting temperatures in DSC analysis, and higher melt flow in rheological studies than the cor- responding PMR-11 polyimides. Long-term isothermal aging studies showed that BTDB- based 12F resins exhibited comparable thermo-oxidative stability to P-PDA based PMR-11 polyimides. The noncoplanar 2- and 2'-disubstituted biphenyldiamine (BTDB) not only lowered the melt viscosities of 12F prepolymers, but also retained reasonable thermal sta- bility of the cured resins. The 12F polyimide resin with p-aminostyrene endcaps showed the best promise for long-term, high-temperature application at 343 C (650 F).

  6. Fuel Additives: Canada bans MMT

    SciTech Connect

    Sissell, K.

    1997-04-16

    The Canadian Senate voted late last week to ban use of the manganese-based fuel additive MMT, produced only in the US by Ethyl. MMT, which has been sold in Canada for the past 20 years and accounts for about half of Ethyl`s Canadian sales, has been criticized by environmentalists, who have raised public health concerns, and automakers, who say it harms emission control systems. {open_quotes}Canada`s vote is a great victory for public health and the environment,{close_quotes} says Environmental Defense Fund executive director Fred Krupp. {open_quotes}The US should move swiftly to follow suit and suspend sales of MMT until adequate toxicity testing on the additive is completed.{close_quotes} EPA had refused to approve MMT for sale because of health concerns but was compelled to do so by a December 1995 court ruling. Ethyl asserts the ban violates Canada`s obligations under Nafta and says it will file a damage claim with the Nafta arbitration panel.

  7. Additive interaction between heterogeneous environmental ...

    EPA Pesticide Factsheets

    BACKGROUND Environmental exposures often occur in tandem; however, epidemiological research often focuses on singular exposures. Statistical interactions among broad, well-characterized environmental domains have not yet been evaluated in association with health. We address this gap by conducting a county-level cross-sectional analysis of interactions between Environmental Quality Index (EQI) domain indices on preterm birth in the Unites States from 2000-2005.METHODS: The EQI, a county-level index constructed for the 2000-2005 time period, was constructed from five domain-specific indices (air, water, land, built and sociodemographic) using principal component analyses. County-level preterm birth rates (n=3141) were estimated using live births from the National Center for Health Statistics. Linear regression was used to estimate prevalence differences (PD) and 95% confidence intervals (CI) comparing worse environmental quality to the better quality for each model for a) each individual domain main effect b) the interaction contrast and c) the two main effects plus interaction effect (i.e. the “net effect”) to show departure from additive interaction for the all U.S counties. Analyses were also performed for subgroupings by four urban/rural strata. RESULTS: We found the suggestion of antagonistic interactions but no synergism, along with several purely additive (i.e., no interaction) associations. In the non-stratified model, we observed antagonistic interac

  8. Additive manufacturing of RF absorbers

    NASA Astrophysics Data System (ADS)

    Mills, Matthew S.

    The ability of additive manufacturing techniques to fabricate integrated electromagnetic absorbers tuned for specific radio frequency bands within structural composites allows for unique combinations of mechanical and electromagnetic properties. These composites and films can be used for RF shielding of sensitive electromagnetic components through in-plane and out-of-plane RF absorption. Structural composites are a common building block of many commercial platforms. These platforms may be placed in situations in which there is a need for embedded RF absorbing properties along with structural properties. Instead of adding radar absorbing treatments to the external surface of existing structures, which adds increased size, weight and cost; it could prove to be advantageous to integrate the microwave absorbing properties directly into the composite during the fabrication process. In this thesis, a method based on additive manufacturing techniques of composites structures with prescribed electromagnetic loss, within the frequency range 1 to 26GHz, is presented. This method utilizes screen printing and nScrypt micro dispensing to pattern a carbon based ink onto low loss substrates. The materials chosen for this study will be presented, and the fabrication technique that these materials went through to create RF absorbing structures will be described. The calibration methods used, the modeling of the RF structures, and the applications in which this technology can be utilized will also be presented.

  9. Stereochemistry of enzymatic water addition to C=C bonds.

    PubMed

    Chen, Bi-Shuang; Otten, Linda G; Hanefeld, Ulf

    2015-01-01

    Water addition to carbon-carbon double bonds using hydratases is attracting great interest in biochemistry. Most of the known hydratases are involved in primary metabolism and to a lesser extent in secondary metabolism. New hydratases have recently been added to the toolbox, both from natural sources or artificial metalloenzymes. In order to comprehensively understand how the hydratases are able to catalyse the water addition to carbon-carbon double bonds, this review will highlight the mechanistic and stereochemical studies of the enzymatic water addition to carbon-carbon double bonds, focusing on the syn/anti-addition and stereochemistry of the reaction.

  10. Strategic Sourcing in the Army

    DTIC Science & Technology

    2013-09-01

    sector:  Total Cost of Ownership tools are applied to understand the life cycle costs of a product or service  Supplier Scorecards to apply a...sourcing efforts, as well as prioritizing new initiatives. In addition to cost and performance goals, any strategic sourcing plan must be balanced with...article/97687/ 39 INITIAL DISTRIBUTION LIST 1. Defense Technical Information Center Ft. Belvoir, Virginia 2. Dudley Knox Library Naval Postgraduate School Monterey, California

  11. Sources of tritium

    SciTech Connect

    Phillips, J.E.; Easterly, C.E.

    1980-12-01

    A review of tritium sources is presented. The tritium production and release rates are discussed for light water reactors (LWRs), heavy water reactors (HWRs), high temperature gas cooled reactors (HTGRs), liquid metal fast breeder reactors (LMFBRs), and molten salt breeder reactors (MSBRs). In addition, release rates are discussed for tritium production facilities, fuel reprocessing plants, weapons detonations, and fusion reactors. A discussion of the chemical form of the release is included. The energy producing facilities are ranked in order of increasing tritium production and release. The ranking is: HTGRs, LWRs, LMFBRs, MSBRs, and HWRs. The majority of tritium has been released in the form of tritiated water.

  12. Additives in fibers and fabrics.

    PubMed Central

    Barker, R H

    1975-01-01

    The additives and contaminants which occur in textile fibers vary widely, depending on the type of fiber and the pretreatment which it has received. Synthetic fibers such as nylon and polyester contain trace amounts of contaminants such as catalysts and catalyst deactivators which remain after the synthesis of the basic polymers. In addition, there are frequently a number of materials which are added to perform specific functions in almost all man-made fibers. Examples of these would include traces of metals or metal salts used as tracers for identification of specific lots of fiber, TiO2 or similar materials added as delustrants, and a host of organic species added for such special purposes as antistatic agents or flame retardants. There may also be considerable quantities of residual monomer or small oligomers dissolved in the polymer matrix. The situation becomes even more complex after the fibers are converted into fabric form. Numerous materials are applied at various stages of fabric preparation to act as lubricants, sizing agents, antistats, bleaches, and wetting agents to facilitate the processing, but these are normally removed before the fabric reaches the cutters of the ultimate consumers and therefore usually do not constitute potential hazards. However, there are many other chemical agents which are frequently added during the later stages of fabric preparation and which are not designed to be removed. Aside from dyes and printing pigments, the most common additive for apparel fabrics is a durable press treatment. This generally involves the use of materials capable of crosslinking cellulosics by reacting through such functions as N-methylolated amides or related compounds such as ureas and carbamates. These materials pose some potential hazards due to both the nitrogenous bases and the formaldehyde which they usually release. There is usually also some residual catalyst in fabrics which have received such treatments. Other types of chemical treatments

  13. Optics of progressive addition lenses.

    PubMed

    Sheedy, J E; Buri, M; Bailey, I L; Azus, J; Borish, I M

    1987-02-01

    The optical characteristics of the major progressive addition lenses were measured using an automated lensometer with a specially designed lens holder to simulate eye rotation. Measurements were made every 3 degrees (about 1.5 mm) and graphs of isospherical equivalent lines and isocylinder lines were developed. Generally the near zone of these lenses is narrower and lower than in bifocal or trifocal lenses. Distinct differences exist between the various progressive lenses. The width of the near zone, rate of power progression, amount of unwanted cylinder (level with the distance center), and clarity of the distance zone are compared for the various lenses. The optical measurements demonstrate an apparent trade-off between the size of the cylinder-free area of the lens and the amount of the cylinder.

  14. Additive and subtractive transparent depth displays

    NASA Astrophysics Data System (ADS)

    Kooi, Frank L.; Toet, Alexander

    2003-09-01

    Image fusion is the generally preferred method to combine two or more images for visual display on a single screen. We demonstrate that perceptual image separation may be preferable over perceptual image fusion for the combined display of enhanced and synthetic imagery. In this context image separation refers to the simultaneous presentation of images on different depth planes of a single display. Image separation allows the user to recognize the source of the information that is displayed. This can be important because synthetic images are more liable to flaws. We have examined methods to optimize perceptual image separation. A true depth difference between enhanced and synthetic imagery works quite well. A standard stereoscopic display based on convergence is less suitable since the two images tend to interfere: the image behind is masked (occluded) by the image in front, which results in poor viewing comfort. This effect places 3D systems based on 3D glasses, as well as most autostereoscopic displays, at a serious disadvantage. A 3D display based on additive or subtractive transparency is acceptable: both the perceptual separation and the viewing comfort are good, but the color of objects depends on the color in the other depth layer(s). A combined additive and subtractive transparent display eliminates this disadvantage and is most suitable for the combined display of enhanced and synthetic imagery. We suggest that the development of such a display system is of a greater practical value than increasing the number of depth planes in autostereoscopic displays.

  15. Open-source software: not quite endsville.

    PubMed

    Stahl, Matthew T

    2005-02-01

    Open-source software will never achieve ubiquity. There are environments in which it simply does not flourish. By its nature, open-source development requires free exchange of ideas, community involvement, and the efforts of talented and dedicated individuals. However, pressures can come from several sources that prevent this from happening. In addition, openness and complex licensing issues invite misuse and abuse. Care must be taken to avoid the pitfalls of open-source software.

  16. Additively manufactured porous tantalum implants.

    PubMed

    Wauthle, Ruben; van der Stok, Johan; Amin Yavari, Saber; Van Humbeeck, Jan; Kruth, Jean-Pierre; Zadpoor, Amir Abbas; Weinans, Harrie; Mulier, Michiel; Schrooten, Jan

    2015-03-01

    The medical device industry's interest in open porous, metallic biomaterials has increased in response to additive manufacturing techniques enabling the production of complex shapes that cannot be produced with conventional techniques. Tantalum is an important metal for medical devices because of its good biocompatibility. In this study selective laser melting technology was used for the first time to manufacture highly porous pure tantalum implants with fully interconnected open pores. The architecture of the porous structure in combination with the material properties of tantalum result in mechanical properties close to those of human bone and allow for bone ingrowth. The bone regeneration performance of the porous tantalum was evaluated in vivo using an orthotopic load-bearing bone defect model in the rat femur. After 12 weeks, substantial bone ingrowth, good quality of the regenerated bone and a strong, functional implant-bone interface connection were observed. Compared to identical porous Ti-6Al-4V structures, laser-melted tantalum shows excellent osteoconductive properties, has a higher normalized fatigue strength and allows for more plastic deformation due to its high ductility. It is therefore concluded that this is a first step towards a new generation of open porous tantalum implants manufactured using selective laser melting.

  17. Additive Transforms Paint into Insulation

    NASA Technical Reports Server (NTRS)

    2007-01-01

    Tech Traders Inc. sought assistance developing low-cost, highly effective coatings and paints that created useful thermal reflectance and were safe and non-toxic. In cooperation with a group of engineers at Kennedy Space Center., Tech Traders created Insuladd, a powder additive made up of microscopic, inert gas-filled, ceramic microspheres that can be mixed into ordinary interior or exterior paint, allowing the paint to act like a layer of insulation. When the paint dries, this forms a radiant heat barrier, turning the ordinary house paint into heat-reflecting thermal paint. According to Tech Traders, the product works with all types of paints and coatings and will not change the coverage rate, application, or adhesion of the paint. Other useful applications include feed storage silos to help prevent feed spoilage, poultry hatcheries to reduce the summer heat and winter cold effects, and on military vehicles and ships. Tech Traders has continued its connection to the aerospace community by recently providing Lockheed Martin Corporation with one of its thermal products for use on the F-22 Raptor.

  18. Sustainability Characterization for Additive Manufacturing

    PubMed Central

    Mani, Mahesh; Lyons, Kevin W; Gupta, SK

    2014-01-01

    Additive manufacturing (AM) has the potential to create geometrically complex parts that require a high degree of customization, using less material and producing less waste. Recent studies have shown that AM can be an economically viable option for use by the industry, yet there are some inherent challenges associated with AM for wider acceptance. The lack of standards in AM impedes its use for parts production since industries primarily depend on established standards in processes and material selection to ensure the consistency and quality. Inability to compare AM performance against traditional manufacturing methods can be a barrier for implementing AM processes. AM process sustainability has become a driver due to growing environmental concerns for manufacturing. This has reinforced the importance to understand and characterize AM processes for sustainability. Process characterization for sustainability will help close the gaps for comparing AM performance to traditional manufacturing methods. Based on a literature review, this paper first examines the potential environmental impacts of AM. A methodology for sustainability characterization of AM is then proposed to serve as a resource for the community to benchmark AM processes for sustainability. Next, research perspectives are discussed along with relevant standardization efforts. PMID:26601038

  19. Sustainability Characterization for Additive Manufacturing.

    PubMed

    Mani, Mahesh; Lyons, Kevin W; Gupta, S K

    2014-01-01

    Additive manufacturing (AM) has the potential to create geometrically complex parts that require a high degree of customization, using less material and producing less waste. Recent studies have shown that AM can be an economically viable option for use by the industry, yet there are some inherent challenges associated with AM for wider acceptance. The lack of standards in AM impedes its use for parts production since industries primarily depend on established standards in processes and material selection to ensure the consistency and quality. Inability to compare AM performance against traditional manufacturing methods can be a barrier for implementing AM processes. AM process sustainability has become a driver due to growing environmental concerns for manufacturing. This has reinforced the importance to understand and characterize AM processes for sustainability. Process characterization for sustainability will help close the gaps for comparing AM performance to traditional manufacturing methods. Based on a literature review, this paper first examines the potential environmental impacts of AM. A methodology for sustainability characterization of AM is then proposed to serve as a resource for the community to benchmark AM processes for sustainability. Next, research perspectives are discussed along with relevant standardization efforts.

  20. Dynamics of ultrasonic additive manufacturing.

    PubMed

    Hehr, Adam; Dapino, Marcelo J

    2017-01-01

    Ultrasonic additive manufacturing (UAM) is a solid-state technology for joining similar and dissimilar metal foils near room temperature by scrubbing them together with ultrasonic vibrations under pressure. Structural dynamics of the welding assembly and work piece influence how energy is transferred during the process and ultimately, part quality. To understand the effect of structural dynamics during UAM, a linear time-invariant model is proposed to relate the inputs of shear force and electric current to resultant welder velocity and voltage. Measured frequency response and operating performance of the welder under no load is used to identify model parameters. Using this model and in-situ measurements, shear force and welder efficiency are estimated to be near 2000N and 80% when welding Al 6061-H18 weld foil, respectively. Shear force and welder efficiency have never been estimated before in UAM. The influence of processing conditions, i.e., welder amplitude, normal force, and weld speed, on shear force and welder efficiency are investigated. Welder velocity was found to strongly influence the shear force magnitude and efficiency while normal force and weld speed showed little to no influence. The proposed model is used to describe high frequency harmonic content in the velocity response of the welder during welding operations and coupling of the UAM build with the welder.

  1. Dimensionless numbers in additive manufacturing

    NASA Astrophysics Data System (ADS)

    Mukherjee, T.; Manvatkar, V.; De, A.; DebRoy, T.

    2017-02-01

    The effects of many process variables and alloy properties on the structure and properties of additively manufactured parts are examined using four dimensionless numbers. The structure and properties of components made from 316 Stainless steel, Ti-6Al-4V, and Inconel 718 powders for various dimensionless heat inputs, Peclet numbers, Marangoni numbers, and Fourier numbers are studied. Temperature fields, cooling rates, solidification parameters, lack of fusion defects, and thermal strains are examined using a well-tested three-dimensional transient heat transfer and fluid flow model. The results show that lack of fusion defects in the fabricated parts can be minimized by strengthening interlayer bonding using high values of dimensionless heat input. The formation of harmful intermetallics such as laves phases in Inconel 718 can be suppressed using low heat input that results in a small molten pool, a steep temperature gradient, and a fast cooling rate. Improved interlayer bonding can be achieved at high Marangoni numbers, which results in vigorous circulation of liquid metal, larger pool dimensions, and greater depth of penetration. A high Fourier number ensures rapid cooling, low thermal distortion, and a high ratio of temperature gradient to the solidification growth rate with a greater tendency of plane front solidification.

  2. Children's understanding of additive concepts.

    PubMed

    Robinson, Katherine M; Dubé, Adam K; Beatch, Jacqueline-Ann

    2017-04-01

    Most research on children's arithmetic concepts is based on one concept at a time, limiting the conclusions that can be made about how children's conceptual knowledge of arithmetic develops. This study examined six arithmetic concepts (identity, negation, commutativity, equivalence, inversion, and addition and subtraction associativity) in Grades 3, 4, and 5. Identity (a-0=a) and negation (a-a=0) were well understood, followed by moderate understanding of commutativity (a+b=b+a) and inversion (a+b-b=a), with weak understanding of equivalence (a+b+c=a+[b+c]) and associativity (a+b-c=[b-c]+a). Understanding increased across grade only for commutativity and equivalence. Four clusters were found: The Weak Concept cluster understood only identity and negation; the Two-Term Concept cluster also understood commutativity; the Inversion Concept cluster understood identity, negation, and inversion; and the Strong Concept cluster had the strongest understanding of all of the concepts. Grade 3 students tended to be in the Weak and Inversion Concept clusters, Grade 4 students were equally likely to be in any of the clusters, and Grade 5 students were most likely to be in the Two-Term and Strong Concept clusters. The findings of this study highlight that conclusions about the development of arithmetic concepts are highly dependent on which concepts are being assessed and underscore the need for multiple concepts to be investigated at the same time.

  3. Capillary discharge source

    DOEpatents

    Bender, III, Howard Albert

    2003-11-25

    Debris generation from an EUV electric discharge plasma source device can be significantly reduced or essentially eliminated by encasing the electrodes with dielectric or electrically insulating material so that the electrodes are shielded from the plasma, and additionally by providing a path for the radiation to exit wherein the electrodes are not exposed to the area where the radiation is collected. The device includes: (a) a body, which is made of an electrically insulating material, that defines a capillary bore that has a proximal end and a distal end and that defines at least one radiation exit; (b) a first electrode that defines a first channel that has a first inlet end that is connected to a source of gas and a first outlet end that is in communication with the capillary bore, wherein the first electrode is positioned at the distal end of the capillary bore; (c) a second electrode that defines a second channel that has a second inlet end that is in communication with the capillary bore and an outlet end, wherein the second electrode is positioned at the proximal end of the capillary bore; and (d) a source of electric potential that is connected across the first and second electrodes, wherein radiation generated within the capillary bore is emitted through the at least one radiation exit and wherein the first electrode and second electrode are shielded from the emitted radiation.

  4. Additives In Meat and Poultry Products

    MedlinePlus

    ... What is a food additive? What is a "direct" food additive? What is an 'indirect" food additive? ... convenience foods. [ Top of Page ] What is a “direct” food additive? According to the FDA, “Direct food ...

  5. 40 CFR 51.117 - Additional provisions for lead.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... smelters, Lead gasoline additive plants, Lead-acid storage battery manufacturing plants that produce 2,000 or more batteries per day. Any other stationary source that actually emits 25 or more tons per year... modified rollback model for the demonstration of attainment as a minimum, but may use an...

  6. Benefits of additives application during combustion of phytomass

    NASA Astrophysics Data System (ADS)

    Palacka, Matej; Vician, Peter; Holubčík, Michal; Jandačka, Jozef

    2016-06-01

    Phytomass, particularly wheat straw as a source of energy has countless benefits, but it has many problems in its direct burn too. The worst problem is the ash flow temperature. The aim of study was to analyze and reduce the problems of the wheat straw combustion. The experiment was conducted under realistic conditions. In this paper was implemented analysis of ash features with and without adding additives into the wheat straw. Selected samples were laboratory processed and examined. The result of the work was the impact of additional additives for ash features.

  7. Uncertainty in source partitioning using stable isotopes.

    PubMed

    Phillips, D L; Gregg, J W

    2001-04-01

    substantially smaller than the population SDs. Proportion SEs were minimized when sources were evenly divided, but increased only slightly as the proportions varied. The variance formulas provided will enable quantification of the precision of source proportion estimates. Graphs are provided to allow rapid assessment of possible combinations of source differences and source and mixture population SDs that will allow source proportion estimates with desired precision. In addition, an Excel spreadsheet to perform the calculations for the source proportions and their variances, SEs, and 95% confidence intervals for the two-source and three-source mixing models can be accessed at http://www.epa.gov/wed/pages/models.htm.

  8. Diversity employment and recruitment sources

    SciTech Connect

    Not Available

    1994-08-01

    Effective human resources management has been identified as one of four critical success factors in the Department of Energy Strategic Plan. The Plan states relative to this factor: ``The Department seeks greater alignment of resources with agency priorities and increased diversification of the workforce, including gender, ethnicity, age, and skills. This diversification will bring new thinking and perspectives that heretofore have not had a voice in departmental decision-making.`` This Guide has been developed as a key tool to assist Department of Energy management and administrative staff in achieving Goal 2 of this critical success factor, which is to ``Ensure a diverse and talented workforce.`` There are numerous sources from which to recruit minorities, women and persons with disabilities. Applying creativity and proactive effort, using traditional and non-traditional approaches, and reaching out to various professional, academic and social communities will increase the reservoir of qualified candidates from which to make selections. In addition, outreach initiatives will undoubtedly yield further benefits such as a richer cultural understanding and diversity awareness. The resource listings presented in this Guide are offered to encourage active participation in the diversity recruitment process. This Guide contains resource listings by state for organizations in the following categories: (1) African American Recruitment Sources; (2) Asian American/Pacific Islander Recruitment Sources; (3) Hispanic Recruitment Sources; (4) Native American/Alaskan Native Recruitment Sources; (5) Persons with Disabilities Recruitment Sources; and (6) Women Recruitment Sources.

  9. The magnitude of the snow-sourced reactive nitrogen flux to the boundary layer in the Uintah Basin, Utah, USA

    NASA Astrophysics Data System (ADS)

    Zatko, Maria; Erbland, Joseph; Savarino, Joel; Geng, Lei; Easley, Lauren; Schauer, Andrew; Bates, Timothy; Quinn, Patricia K.; Light, Bonnie; Morison, David; Osthoff, Hans D.; Lyman, Seth; Neff, William; Yuan, Bin; Alexander, Becky

    2016-11-01

    Reactive nitrogen (Nr = NO, NO2, HONO) and volatile organic carbon emissions from oil and gas extraction activities play a major role in wintertime ground-level ozone exceedance events of up to 140 ppb in the Uintah Basin in eastern Utah. Such events occur only when the ground is snow covered, due to the impacts of snow on the stability and depth of the boundary layer and ultraviolet actinic flux at the surface. Recycling of reactive nitrogen from the photolysis of snow nitrate has been observed in polar and mid-latitude snow, but snow-sourced reactive nitrogen fluxes in mid-latitude regions have not yet been quantified in the field. Here we present vertical profiles of snow nitrate concentration and nitrogen isotopes (δ15N) collected during the Uintah Basin Winter Ozone Study 2014 (UBWOS 2014), along with observations of insoluble light-absorbing impurities, radiation equivalent mean ice grain radii, and snow density that determine snow optical properties. We use the snow optical properties and nitrate concentrations to calculate ultraviolet actinic flux in snow and the production of Nr from the photolysis of snow nitrate. The observed δ15N(NO3-) is used to constrain modeled fractional loss of snow nitrate in a snow chemistry column model, and thus the source of Nr to the overlying boundary layer. Snow-surface δ15N(NO3-) measurements range from -5 to 10 ‰ and suggest that the local nitrate burden in the Uintah Basin is dominated by primary emissions from anthropogenic sources, except during fresh snowfall events, where remote NOx sources from beyond the basin are dominant. Modeled daily averaged snow-sourced Nr fluxes range from 5.6 to 71 × 107 molec cm-2 s-1 over the course of the field campaign, with a maximum noontime value of 3.1 × 109 molec cm-2 s-1. The top-down emission estimate of primary, anthropogenic NOx in Uintah and Duchesne counties is at least 300 times higher than the estimated snow NOx emissions presented in this study. Our results suggest

  10. Perovskite photonic sources

    NASA Astrophysics Data System (ADS)

    Sutherland, Brandon R.; Sargent, Edward H.

    2016-05-01

    The field of solution-processed semiconductors has made great strides; however, it has yet to enable electrically driven lasers. To achieve this goal, improved materials are required that combine efficient (>50% quantum yield) radiative recombination under high injection, large and balanced charge-carrier mobilities in excess of 10 cm2 V-1 s-1, free-carrier densities greater than 1017 cm-3 and gain coefficients exceeding 104 cm-1. Solid-state perovskites are -- in addition to galvanizing the field of solar electricity -- showing great promise in photonic sources, and may be the answer to realizing solution-cast laser diodes. Here, we discuss the properties of perovskites that benefit light emission, review recent progress in perovskite electroluminescent diodes and optically pumped lasers, and examine the remaining challenges in achieving continuous-wave and electrically driven lasing.

  11. Investigating Microvibration Sources Modelling

    NASA Astrophysics Data System (ADS)

    Addari, Daniele; Aglietti, Guglielmo S.; Remedia, Marcello

    2014-06-01

    One of the challenges related to microvibration is investigating the characterisation of the microvibration sources (here emphasis is given to reaction wheel assemblies) on board satellites. This usually involves series of experiments to characterise the hardware and produce representative models. Here we present a methodology that gives good estimates covering a wide frequency range and reduce the complexity of the test campaign.In addition, a practical example of coupling between a reaction wheel assembly and a structural panel where the coupled loads have been estimated using the mathematical model and compared with experimental test results (retrieved using an interface load transducer) will be presented, giving indications of the level of accuracy that can be expected from this type of analyses.

  12. Food protein sources.

    PubMed

    Pirie, N W

    1976-07-01

    Work on food, planned by the U.M. (Use and Management) Section of the U.K. committe, was limited to sources of protein because we agreed that more problems calling for research were likely to arise in getting adequate supplies of protein than of other types of food. Deer meat can be produced on land too rough and exposed for sheep; parts of the work on their metabolism and food requirements necessitated building a mobile laboratory. The manner in which the nutritive value of maize is affected by changes in the ratios in which the component proteins are present, stimulated similar studies on barley and groundnut. There is good quality protein in coconuts and leaves but its use in human food is restricted by the presence of fibre. Methods for separating protein from fibre and other deleterious components were improved. In cooperation with scientists in India and Nigeria, the potential yield of protein-deficient foods. e.g. cassava, were 'ennobled' by growing micro-organisms on them with the addition of a cheap source of nitrogen.

  13. Problems with packaged sources in foreign countries

    SciTech Connect

    Abeyta, Cristy L; Matzke, James L; Zarling, John; Tompkin, J. Andrew

    2010-01-01

    The Global Threat Reduction Initiative's (GTRI) Off-Site Source Recovery Project (OSRP), which is administered by the Los Alamos National Laboratory (LANL), removes excess, unwanted, abandoned, or orphan radioactive sealed sources that pose a potential threat to national security, public health, and safety. In total, GTRI/OSRP has been able to recover more than 25,000 excess and unwanted sealed sources from over 825 sites. In addition to transuranic sources, the GTRI/OSRP mission now includes recovery of beta/gamma emitting sources, which are of concern to both the U.S. government and the International Atomic Energy Agency (IAEA). This paper provides a synopsis of cooperative efforts in foreign countries to remove excess and unwanted sealed sources by discussing three topical areas: (1) The Regional Partnership with the International Atomic Energy Agency; (2) Challenges in repatriating sealed sources; and (3) Options for repatriating sealed sources.

  14. Conducting Source Water Assessments

    EPA Pesticide Factsheets

    This page presents background information on the source water assessment steps, the four steps of a source wter assessment, and how to use the results of an assessment to protect drinking water sources.

  15. Overview of Food Ingredients, Additives and Colors

    MedlinePlus

    ... pesticides where other legal premarket approval requirements apply. Direct food additives are those that are added to ... and other foods to add texture -- is a direct additive. Most direct additives are identified on the ...

  16. Source Identification and Location Techniques

    NASA Technical Reports Server (NTRS)

    Weir, Donald; Bridges, James; Agboola, Femi; Dougherty, Robert

    2001-01-01

    Mr. Weir presented source location results obtained from an engine test as part of the Engine Validation of Noise Reduction Concepts program. Two types of microphone arrays were used in this program to determine the jet noise source distribution for the exhaust from a 4.3 bypass ratio turbofan engine. One was a linear array of 16 microphones located on a 25 ft. sideline and the other was a 103 microphone 3-D "cage" array in the near field of the jet. Data were obtained from a baseline nozzle and from numerous nozzle configuration using chevrons and/or tabs to reduce the jet noise. Mr. Weir presented data from two configurations: the baseline nozzle and a nozzle configuration with chevrons on both the core and bypass nozzles. This chevron configuration had achieved a jet noise reduction of 4 EPNdB in small scale tests conducted at the Glenn Research Center. IR imaging showed that the chevrons produced significant improvements in mixing and greatly reduced the length of the jet potential core. Comparison of source location data from the 1-D phased array showed a shift of the noise sources towards the nozzle and clear reductions of the sources due to the noise reduction devices. Data from the 3-D array showed a single source at a frequency of 125 Hz. located several diameters downstream from the nozzle exit. At 250 and 400 Hz., multiple sources, periodically spaced, appeared to exist downstream of the nozzle. The trend of source location moving toward the nozzle exit with increasing frequency was also observed. The 3-D array data also showed a reduction in source strength with the addition of chevrons. The overall trend of source location with frequency was compared for the two arrays and with classical experience. Similar trends were observed. Although overall trends with frequency and addition of suppression devices were consistent between the data from the 1-D and the 3-D arrays, a comparison of the details of the inferred source locations did show differences. A

  17. Uniform Additivity in Classical and Quantum Information

    NASA Astrophysics Data System (ADS)

    Cross, Andrew; Li, Ke; Smith, Graeme

    2017-01-01

    Information theory quantifies the optimal rates of resource interconversions, usually in terms of entropies. However, nonadditivity often makes evaluating entropic formulas intractable. In a few auspicious cases, additivity allows a full characterization of optimal rates. We study uniform additivity of formulas, which is easily evaluated and captures all known additive quantum formulas. Our complete characterization of uniform additivity exposes an intriguing new additive quantity and identifies a remarkable coincidence—the classical and quantum uniformly additive functions with one auxiliary variable are identical.

  18. 16 CFR 1102.16 - Additional information.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... PUBLICLY AVAILABLE CONSUMER PRODUCT SAFETY INFORMATION DATABASE Content Requirements § 1102.16 Additional... in the Database any additional information it determines to be in the public interest,...

  19. 16 CFR 1102.16 - Additional information.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... PUBLICLY AVAILABLE CONSUMER PRODUCT SAFETY INFORMATION DATABASE Content Requirements § 1102.16 Additional... in the Database any additional information it determines to be in the public interest,...

  20. 16 CFR 1102.16 - Additional information.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... PUBLICLY AVAILABLE CONSUMER PRODUCT SAFETY INFORMATION DATABASE Content Requirements § 1102.16 Additional... in the Database any additional information it determines to be in the public interest,...

  1. 40 CFR 262.43 - Additional reporting.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...) STANDARDS APPLICABLE TO GENERATORS OF HAZARDOUS WASTE Recordkeeping and Reporting § 262.43 Additional... require generators to furnish additional reports concerning the quantities and disposition of...

  2. 40 CFR 262.43 - Additional reporting.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...) STANDARDS APPLICABLE TO GENERATORS OF HAZARDOUS WASTE Recordkeeping and Reporting § 262.43 Additional... require generators to furnish additional reports concerning the quantities and disposition of...

  3. 40 CFR 262.43 - Additional reporting.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) STANDARDS APPLICABLE TO GENERATORS OF HAZARDOUS WASTE Recordkeeping and Reporting § 262.43 Additional... require generators to furnish additional reports concerning the quantities and disposition of...

  4. 40 CFR 262.43 - Additional reporting.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) STANDARDS APPLICABLE TO GENERATORS OF HAZARDOUS WASTE Recordkeeping and Reporting § 262.43 Additional... require generators to furnish additional reports concerning the quantities and disposition of...

  5. 40 CFR 262.43 - Additional reporting.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...) STANDARDS APPLICABLE TO GENERATORS OF HAZARDOUS WASTE Recordkeeping and Reporting § 262.43 Additional... require generators to furnish additional reports concerning the quantities and disposition of...

  6. Energy source for comet outbursts

    NASA Technical Reports Server (NTRS)

    Patashnick, H.; Schuerman, D. W.; Rupprecht, G.

    1974-01-01

    Development of a mechanism explaining the internal source of energy of comet outbursts. A mechanism is proposed which automatically provides a source of particulate matter which creates a huge surface area which contains a substantial percentage of amorphous ice, so that the phase transition of the amorphous ice to a cubic structure provides a release of energy which may be responsible for the outbursts observed in many comets. In addition, the volume into which the transition can propagate is estimated for a spherical comet with a radius of 5 km.

  7. Online bibliographic sources in hydrology

    USGS Publications Warehouse

    Wild, Emily C.; Havener, W. Michael

    2001-01-01

    Traditional commercial bibliographic databases and indexes provide some access to hydrology materials produced by the government; however, these sources do not provide comprehensive coverage of relevant hydrologic publications. This paper discusses bibliographic information available from the federal government and state geological surveys, water resources agencies, and depositories. In addition to information in these databases, the paper describes the scope, styles of citing, subject terminology, and the ways these information sources are currently being searched, formally and informally, by hydrologists. Information available from the federal and state agencies and from the state depositories might be missed by limiting searches to commercially distributed databases.

  8. Handbook of Reference Sources. Second Edition.

    ERIC Educational Resources Information Center

    Nichols, Margaret Irby

    Designed to serve as a selection aid for small public libraries and to list important sources available through the major resource centers of the Texas Library System, this bibliography lists 804 annotated reference sources with 126 additional works named within the annotations. The books are grouped into 18 major areas, each of which is broken…

  9. Effects of Epistemological Sensitization on Source Choices

    ERIC Educational Resources Information Center

    Porsch, Torsten; Bromme, Rainer

    2011-01-01

    The uneven distribution of knowledge within modern societies requires a reliance on sources (e.g., reference books, teachers, the Internet) in addition to own experience. Most scientific issues are far too complex to be understood in any depth by laypersons. Successful knowledge acquisition comprises the ability to vary the amount of sources used…

  10. NONPOINT SOURCES AND WATER QUALITY TRADING

    EPA Science Inventory

    Management of nonpoint sources (NPS) of nutrients may reduce discharge levels more cost effectively than can additional controls on point sources (PS); water quality trading (WQT), where a PS buys nutrient or sediment reductions from an NPS, may be an alternative means for the PS...

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

    NASA Astrophysics Data System (ADS)

    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

  12. How cigarette additives are used to mask environmental tobacco smoke

    PubMed Central

    Connolly, G.; Wayne, G.; Lymperis, D.; Doherty, M.

    2000-01-01

    OBJECTIVE—To understand the tobacco industry's research on and use of cigarette additives that alter the perception of exposure to environmental tobacco smoke (ETS).
DATA SOURCES—Internal documents from four websites maintained by the major US tobacco manufacturers and company patents pertaining to the use of ETS altering additives obtained from the US Patent and Trademark Office online database.
STUDY SELECTION—Electronic searches of the four industry websites and the US patent database were conducted using keywords to identify relevant data.
DATA EXTRACTION—Industry documents and patents obtained using an exploratory snowball sampling method were reviewed and grouped into four general categories according to whether the additive(s) described affected ETS visibility, odour, irritation, or emissions. Accuracy of isolated findings was validated through cross comparison of the data sources.
DATA SYNTHESIS—Results of this preliminary study provide evidence that tobacco manufacturers have conducted extensive research on the use of chemical additives to reduce, mask, or otherwise alter the visibility, odour, irritation, or emission of ETS.
CONCLUSIONS—Findings suggest that the tobacco industry uses additives to reduce the perception of ETS. To protect the public, appropriate regulation of tobacco additives should be mandated.


Keywords: environmental tobacco smoke; tobacco industry; additives; masking PMID:10982572

  13. 14 CFR 1274.917 - Additional funds.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Additional funds. 1274.917 Section 1274.917... FIRMS Other Provisions and Special Conditions § 1274.917 Additional funds. Additional Funds July 2002... under the terms of this cooperative agreement. NASA is under no obligation to provide additional...

  14. A single-source precursor approach to solution processed indium arsenide thin films† †Electronic supplementary information (ESI) available: Table listing selected bond lengths and angles for InAs precursor complex. Cross-sectional SEM of InAs thin film. XPS depth profile spectra of InAs thin film. Valence band XPS of InAs thin film and standard. CCDC 1477895. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c6tc02293f Click here for additional data file. Click here for additional data file.

    PubMed Central

    Marchand, Peter; Sathasivam, Sanjayan; Williamson, Benjamin A. D.; Pugh, David; Bawaked, Salem M.; Basahel, Sulaiman N.; Obaid, Abdullah Y.; Scanlon, David O.; Parkin, Ivan P.

    2016-01-01

    This paper reports the synthesis of the novel single-source precursor, [{(MeInAstBu)3}2(Me2InAs(tBu)H)2] and the subsequent first report of aerosol-assisted chemical vapour deposition of InAs thin films. Owing to the use of the single-source precursor, highly crystalline and stoichiometric films were grown at a relatively low deposition temperature of 450 °C. Core level XPS depth profiling studies showed some partial oxidation of the film surface, however this was self-limiting and disappeared on etch profiles. Valence band XPS analysis matched well with the simulated density of state spectrum. Hall effect measurements performed on the films showed that the films were n-type with promising resistivity (3.6 × 10–3 Ω cm) and carrier mobility (410 cm2 V–1 s–1) values despite growth on amorphous glass substrates. PMID:27774150

  15. Metal Additive Manufacturing: A Review of Mechanical Properties

    NASA Astrophysics Data System (ADS)

    Lewandowski, John J.; Seifi, Mohsen

    2016-07-01

    This article reviews published data on the mechanical properties of additively manufactured metallic materials. The additive manufacturing techniques utilized to generate samples covered in this review include powder bed fusion (e.g., EBM, SLM, DMLS) and directed energy deposition (e.g., LENS, EBF3). Although only a limited number of metallic alloy systems are currently available for additive manufacturing (e.g., Ti-6Al-4V, TiAl, stainless steel, Inconel 625/718, and Al-Si-10Mg), the bulk of the published mechanical properties information has been generated on Ti-6Al-4V. However, summary tables for published mechanical properties and/or key figures are included for each of the alloys listed above, grouped by the additive technique used to generate the data. Published values for mechanical properties obtained from hardness, tension/compression, fracture toughness, fatigue crack growth, and high cycle fatigue are included for as-built, heat-treated, and/or HIP conditions, when available. The effects of test orientation/build direction on properties, when available, are also provided, along with discussion of the potential source(s) (e.g., texture, microstructure changes, defects) of anisotropy in properties. Recommendations for additional work are also provided.

  16. Unexpectedly high indoor hydroxyl radical concentrations associated with nitrous acid.

    PubMed

    Gómez Alvarez, Elena; Amedro, Damien; Afif, Charbel; Gligorovski, Sasho; Schoemaecker, Coralie; Schoemacker, Coralie; Fittschen, Christa; Doussin, Jean-Francois; Wortham, Henri

    2013-08-13

    The hydroxyl (OH) radical is the most important oxidant in the atmosphere since it controls its self-oxidizing capacity. The main sources of OH radicals are the photolysis of ozone and the photolysis of nitrous acid (HONO). Due to the attenuation of solar radiation in the indoor environment, the possibility of OH formation through photolytic pathways indoors has been ignored up to now. In the indoor air, the ozonolysis of alkenes has been suggested as an alternative route of OH formation. Models and indirect measurements performed up to now according to this hypothesis suggest concentrations of OH radicals on the order of 10(4)-10(5) molecules per cubic centimeter. Here, we present direct measurements of significant amounts of OH radicals of up to 1.8⋅10(6) molecules per cubic centimeter during an experimental campaign carried out in a school classroom in Marseille. This concentration is on the same order of magnitude of outdoor OH levels in the urban scenario. We also show that photolysis of HONO is an important source of OH radicals indoors under certain conditions (i.e., direct solar irradiation inside the room). Additionally, the OH concentrations were found to follow a linear dependence with the product J(HONO)⋅[HONO]. This was also supported by using a simple quasiphotostationary state model on the OH radical budget. These findings force a change in our understanding of indoor air quality because the reactivity linked to OH would involve formation of secondary species through chemical reactions that are potentially more hazardous than the primary pollutants in the indoor air.

  17. Unexpectedly high indoor hydroxyl radical concentrations associated with nitrous acid

    PubMed Central

    Gómez Alvarez, Elena; Amedro, Damien; Afif, Charbel; Gligorovski, Sasho; Schoemaecker, Coralie; Fittschen, Christa; Doussin, Jean-Francois; Wortham, Henri

    2013-01-01

    The hydroxyl (OH) radical is the most important oxidant in the atmosphere since it controls its self-oxidizing capacity. The main sources of OH radicals are the photolysis of ozone and the photolysis of nitrous acid (HONO). Due to the attenuation of solar radiation in the indoor environment, the possibility of OH formation through photolytic pathways indoors has been ignored up to now. In the indoor air, the ozonolysis of alkenes has been suggested as an alternative route of OH formation. Models and indirect measurements performed up to now according to this hypothesis suggest concentrations of OH radicals on the order of 104–105 molecules per cubic centimeter. Here, we present direct measurements of significant amounts of OH radicals of up to 1.8⋅106 molecules per cubic centimeter during an experimental campaign carried out in a school classroom in Marseille. This concentration is on the same order of magnitude of outdoor OH levels in the urban scenario. We also show that photolysis of HONO is an important source of OH radicals indoors under certain conditions (i.e., direct solar irradiation inside the room). Additionally, the OH concentrations were found to follow a linear dependence with the product J(HONO)⋅[HONO]. This was also supported by using a simple quasiphotostationary state model on the OH radical budget. These findings force a change in our understanding of indoor air quality because the reactivity linked to OH would involve formation of secondary species through chemical reactions that are potentially more hazardous than the primary pollutants in the indoor air. PMID:23898188

  18. ANS cold source neutronics analysis

    SciTech Connect

    Lillie, R.A.

    1994-06-01

    This paper describes the calculational procedures employed in the ongoing neutronics analysis of the ANS cold source and presents in chronological order some of the more important results from the one- and two-dimensional discrete calculations performed to date in support of the ANS cold source design. In particular, cold neutron currents from cryostat shapes which can be adequately modeled with two-dimensional geometries are compared with and without reentrant cavities. Also, results are presented from one-dimensional comparative liquid hydrogen vs liquid deuterium calculations in which the density, placement, and para-ortho mixture of liquid hydrogen is investigated. In addition, the evolution of the ANS conceptual design cold source from an initial short cylindrical cryostat with hemispherical upper and lower heads employing a natural convection liquid deuterium circulation system to the final spherical design employing a pumped system is described. Finally, performance data and heating rates are presented for some possible alternate ANS cryostat and vacuum jacket materials.

  19. Pulsed reflex ion source studies

    SciTech Connect

    Bickes, Jr., R. W.; O'Hagan, J. B.

    1980-11-01

    Parametric studies of demountable versions of the pulsed ion source used in Controlatron and Zetatron neutron tubes were carried out. The goal of these experiments, a continuation of earlier work by Bacon and O'Hagan, was to investigate the deuteron beam intensity as a function of source geometry, electrode materials, operating conditions and pulse length. Geometric variations produced only modest changes in the ion beam intensity; the most sensitive parameter was the length of the secondary cathode. There is some evidence that the addition of oxygen either in the gas feed or using alumina on the cathode surfaces can increase the atomic ion fraction. The lowest reliable operating source pressure was approximately 1.33 Pa. The longest pulse length was about 1.2 ms. Difficulties in measuring the ion currents are discussed and suggestions for future experiments are briefly outlined.

  20. A review of terahertz sources

    NASA Astrophysics Data System (ADS)

    Lewis, R. A.

    2014-09-01

    Bibliometric data set the scene by illustrating the growth of terahertz work and the present interest in terahertz science and technology. After locating terahertz sources within the broader context of terahertz systems, an overview is given of the range of available sources, emphasizing recent developments. The focus then narrows to terahertz sources that rely on surface phenomena. Three are highlighted. Optical rectification, usually thought of as a bulk process, may in addition exhibit a surface contribution, which, in some cases, predominates. Transient surface currents, for convenience often separated into drift and diffusion currents, are well understood according to Monte Carlo modelling. Finally, terahertz surface emission by mechanical means—in the absence of photoexcitation—is described.

  1. Compact portable electric power sources

    SciTech Connect

    Fry, D.N.; Holcomb, D.E.; Munro, J.K.; Oakes, L.C.; Matson, M.J.

    1997-02-01

    This report provides an overview of recent advances in portable electric power source (PEPS) technology and an assessment of emerging PEPS technologies that may meet US Special Operations Command`s (SOCOM) needs in the next 1--2- and 3--5-year time frames. The assessment was performed through a literature search and interviews with experts in various laboratories and companies. Nineteen PEPS technologies were reviewed and characterized as (1) PEPSs that meet SOCOM requirements; (2) PEPSs that could fulfill requirements for special field conditions and locations; (3) potentially high-payoff sources that require additional R and D; and (4) sources unlikely to meet present SOCOM requirements. 6 figs., 10 tabs.

  2. Decision-Making, Science and Gasoline Additives

    NASA Astrophysics Data System (ADS)

    Weaver, J. W.; Small, M. C.

    2001-12-01

    Methyl-tert butyl ether (MTBE) has been used as a gasoline additive to serve two major purposes. The first use was as an octane-enhancer to replace organic lead, beginning in 1979. The second use, which began about 1992, was as a oxygenated additive to meet requirements of the Clean Air Act Amendments (CAAA) of 1990. Generally, the amount of MTBE used for octane enhancement was lower than that required to meet CAAA requirements. An unintended consequence of MTBE use has been widespread groundwater contamination. The decision to use certain amounts of MTBE or other chemcials as gasoline additives is the outcome of economic, regulatory, policy, political, and scientific considerations. Decision makers ask questions such as "How do ground water impacts change with changing MTBE content? How many wells would be impacted? and What are the associated costs?" These are best answered through scientific inquiry, but many different approaches could be developed. Decision criteria include time, money, comprehensiveness, and complexity of the approach. Because results must be communicated to a non-technical audience, there is a trade off between the complexity of the approach and the ability to convince economists, lawyers and policy makers that results make sense. The question on MTBE content posed above was investigated using transport models, a release scenario and gasoline composition. Because of the inability of transport models to predict future concentrations, an approach was chosen to base comparative assessment on a calibrated model. By taking this approach, "generic" modeling with arbitrarily selected parameters was avoided and the validity of the simulation results rests upon relatively small extrapolations from the original calibrated models. A set of simulations was performed that assumed 3% (octane enhancement) and 11% (CAAA) MTBE in gasoline. The results were that ground water concentrations would be reduced in proportion to the reduction of MTBE in the fuel

  3. Anomaly metrics to differentiate threat sources from benign sources in primary vehicle screening.

    SciTech Connect

    Cohen, Israel Dov; Mengesha, Wondwosen

    2011-09-01

    Discrimination of benign sources from threat sources at Port of Entries (POE) is of a great importance in efficient screening of cargo and vehicles using Radiation Portal Monitors (RPM). Currently RPM's ability to distinguish these radiological sources is seriously hampered by the energy resolution of the deployed RPMs. As naturally occurring radioactive materials (NORM) are ubiquitous in commerce, false alarms are problematic as they require additional resources in secondary inspection in addition to impacts on commerce. To increase the sensitivity of such detection systems without increasing false alarm rates, alarm metrics need to incorporate the ability to distinguish benign and threat sources. Principal component analysis (PCA) and clustering technique were implemented in the present study. Such techniques were investigated for their potential to lower false alarm rates and/or increase sensitivity to weaker threat sources without loss of specificity. Results of the investigation demonstrated improved sensitivity and specificity in discriminating benign sources from threat sources.

  4. Compatibility of lubricant additives with HFC refrigerants and synthetic lubricants. Final report, Part 1

    SciTech Connect

    Cavestri, R.C.

    1997-07-01

    Part one of this research provides manufacturers of components of air-conditioning and refrigeration equipment with a useful list of lubricant additives, sources, functional properties and chemical species. The list in part one is comprised of domestic lubricant additive suppliers and the results of a literature search that was specifically targeted for additives reported to be useful in polyolester chemistry.

  5. 36 CFR 1290.3 - Sources of assassination records and additional records and information.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...) Agencies, offices, and entities of the executing, legislative, and judicial branches of the Federal Government; (b) Agencies, offices, and entities of the executive, legislative, and judicial branches of state and local governments; (c) Record repositories and archives of Federal, state, and local...

  6. 36 CFR 1290.3 - Sources of assassination records and additional records and information.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) Agencies, offices, and entities of the executing, legislative, and judicial branches of the Federal Government; (b) Agencies, offices, and entities of the executive, legislative, and judicial branches of state and local governments; (c) Record repositories and archives of Federal, state, and local...

  7. 36 CFR 1290.3 - Sources of assassination records and additional records and information.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...) Agencies, offices, and entities of the executing, legislative, and judicial branches of the Federal Government; (b) Agencies, offices, and entities of the executive, legislative, and judicial branches of state and local governments; (c) Record repositories and archives of Federal, state, and local...

  8. Mobile hard substrata - An additional biodiversity source in a high latitude shallow subtidal system

    NASA Astrophysics Data System (ADS)

    Balazy, Piotr; Kuklinski, Piotr

    2013-03-01

    This study demonstrates the importance of a hard mobile substratum (hermit crab shells) for Arctic biodiversity. Based on previous observations from other geographic regions we hypothesized that this niche at high latitudes would support a higher biodiversity of epifauna than might be predicted from similar substrata. We test whether the hermit crab epifauna is specific to that substratum providing unique biodiversity components to the local community. From four study sites in Isfjorden (78°N), West Spitsbergen and two study sites in Northern Norway (69°N) we collected approximately 50 each of hermit crabs, gastropods and pebbles, of visually similar surface area using SCUBA diving. Hermit crab shells were colonized by a larger number of epifaunal species than either gastropods or pebbles, even when they were of a larger size. Among 87 taxa found on all the three substrata, 22 occurred only on hermit crab shells. Except for two study sites hermit crab shells also supported more individuals. This study shows that the contribution of shells carried by hermit crabs to high-latitude, shallow-subtidal diversity is higher than might be predicted by their surface area alone and that hermit crabs modify, maintain and create a unique habitat. This is the result of a number of factors interacting positively on the presence of epifauna including shell surface heterogeneity and the complex influence of the crab host.

  9. Measurement of Insertion Loss of an Acoustic Treatment in the Presence of Additional Uncorrelated Sound Sources

    NASA Technical Reports Server (NTRS)

    Klos, Jacob; Palumbo, Daniel L.

    2003-01-01

    A method to intended for measurement of the insertion loss of an acoustic treatment applied to an aircraft fuselage in-situ is documented in this paper. Using this method, the performance of a treatment applied to a limited portion of an aircraft fuselage can be assessed even though the untreated fuselage also radiates into the cabin, corrupting the intensity measurement. This corrupting noise in the intensity measurement incoherent with the panel vibration of interest is removed by correlating the intensity to reference transducers such as accelerometers. Insertion loss of the acoustic treatments is estimated from the ratio of correlated intensity measurements with and without a treatment applied. In the case of turbulent boundary layer excitation of the fuselage, this technique can be used to assess the performance of noise control methods without requiring treatment of the entire fuselage. Several experimental studies and numerical simulations have been conducted, and results from three case studies are documented in this paper. Conclusions are drawn about the use of this method to study aircraft sidewall treatments.

  10. 36 CFR 1290.3 - Sources of assassination records and additional records and information.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... IMPLEMENTATION OF THE PRESIDENT JOHN F. KENNEDY ASSASSINATION RECORDS COLLECTION ACT OF 1992 (JFK ACT) § 1290.3...; (g) Persons, including individuals and corporations, who have themselves created or have...

  11. 75 FR 74773 - Mandatory Reporting of Greenhouse Gases: Additional Sources of Fluorinated GHGs

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-01

    ..., Methods for Estimating Air Emissions from Chemical Manufacturing Facilities; Protocol for Equipment Leak... chemical vapor deposition process (CVD) or other manufacturing processes use N 2 O. Production processes.... N 2 O emissions from chemical vapor deposition and other electronics manufacturing...

  12. 75 FR 18651 - Mandatory Reporting of Greenhouse Gases: Additional Sources of Fluorinated GHGs

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-12

    ... where emissions from electronics manufacturing processes such as plasma etching, chemical vapor... methods for estimating N 2 O emissions from chemical vapor deposition and other manufacturing processes... received comments that clarified that N 2 O is used primarily in the chemical vapor deposition...

  13. The Linguistic Landscape as an Additional Source of Input in Second Language Acquisition

    ERIC Educational Resources Information Center

    Cenoz, Jasone; Gorter, Durk

    2008-01-01

    In this article we explore the role that the linguistic landscape, in the sense of all the written language in the public space, can have in second language acquisition (SLA). The linguistic landscape has symbolic and informative functions and it is multimodal, because it combines visual and printed texts, and multilingual, because it uses several…

  14. Addition of dietary fiber sources to shakes reduces postprandial glycemia and alters food intake.

    PubMed

    Galvão Cândido, Flávia; Silva Ton, Winder Tadeu; Gonçalves Alfenas, Rita de Cássia

    2014-09-15

    Introducción: Obesidad y diabetes de tipo 2 pueden ser controlados por alimentos capaces de modular la ingesta de alimentos y la glucemia. Objetivos: Se investigó si la adición de alimentos fuentes de fibra o fasolamina a batidos puede controlar la ingesta de alimentos y reducir la glucemia posprandial. Métodos: Estudio aleatorizado, simple ciego, de diseño cruzado (ingesta de alimentos:n=22; glucemia:n=10). Cinco batidos con cantidades similares de macronutrientes (C - control batido, SA - salvado de avena batido, L - linaza batido, FB - extracto de frijol blanco batido y PI - harina de plátano no maduro batido) fueron consumidos en cinco días no consecutivos. Las participantes registraron la ingesta de alimentos en las 24 horas subsiguientes. La glucosa en sangre se midió a 0 (inmediatamente antes), 15, 30, 45, 60, 90 y 120 minutos después de la ingestión de cada batido y se calcularon las áreas incrementales bajo las curvas (AIBC). Resultados: En comparación a C, hubo un aumento significativo en la ingesta de fibra después de que el consumo de SA(+17,9g), SL(+19,1g), y PI(+12,6g), y en la grasa después del consumo de SA(+25,4g). Se encontró una reducción no significativa de la ingesta diaria de energía en L (1524kJ, P=0,10) en comparación con C. Hubo una reducción del 43% en el AIBC (P=0,03) en respuesta al consumo PI. Conclusiones: Harina de plátano no maduro reduce la respuesta glucémica posprandial de batidos casi a la mitad. El efecto de salvado de avena y linaza en la ingesta de alimentos requiere mayor investigación en estudios a largo plazo.

  15. 76 FR 36339 - Mandatory Reporting of Greenhouse Gases: Additional Sources of Fluorinated GHGs: Extension of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-22

    ... Fluorinated GHGs: Extension of Best Available Monitoring Provisions for Electronics Manufacturing AGENCY... provisions for the use of best available monitoring methods in Subpart I: Electronics Manufacturing of the...: Electronics Manufacturing of the Greenhouse Gas Reporting Rule on December 1, 2010 (75 FR 74774). This...

  16. ADHD Diet: Do Food Additives Cause Hyperactivity?

    MedlinePlus

    ... There's no solid evidence that food additives cause attention-deficit/hyperactivity disorder (ADHD). However, the topic of food additives and their possible effects is controversial. Some studies indicate that certain food ...

  17. Additive Manufacturing of Aerospace Propulsion Components

    NASA Technical Reports Server (NTRS)

    Misra, Ajay K.; Grady, Joseph E.; Carter, Robert

    2015-01-01

    The presentation will provide an overview of ongoing activities on additive manufacturing of aerospace propulsion components, which included rocket propulsion and gas turbine engines. Future opportunities on additive manufacturing of hybrid electric propulsion components will be discussed.

  18. [Safety of food additives in Japan].

    PubMed

    Ito, Sumio

    2011-01-01

    Recently, many accidents relating to food happened in Japan. The consumer's distrust for food, food companies, and the administration is increasing. The consumer especially has an extreme refusal feeling for chemicals such as food additives and agricultural chemicals, and begins to request agricultural chemical-free vegetables and food additive-free food. Food companies also state no agricultural chemicals and no food additives to correspond with consumers' request and aim at differentiating. The food additive is that the Ministry of Health, Labour and Welfare specifies the one that person's health might not be ruined by providing for Food Sanitation Law Article 10 in our country. The standard for food additives and standard for use of food additives are provided according to regulations of Food Sanitation Law Article 11. Therefore, it is thought that the food additive used is safe now. Then, it reports on the procedure and the safety examination, etc. in our country for designation for food additive this time.

  19. Additive-driven assembly of block copolymers

    NASA Astrophysics Data System (ADS)

    Lin, Ying; Daga, Vikram; Anderson, Eric; Watkins, James

    2011-03-01

    One challenge to the formation of well ordered hybrid materials is the incorporation of nanoscale additives including metal, semiconductor and dielectric nanoparticles at high loadings while maintaining strong segregation. Here we describe the molecular and functional design of small molecule and nanoparticle additives that enhance phase segregation in their block copolymer host and enable high additive loadings. Our approach includes the use of hydrogen bond interactions between the functional groups on the additive or particle that serve as hydrogen bond donors and one segment of the block copolymer containing hydrogen bond acceptors. Further, the additives show strong selectively towards the targeted domains, leading to enhancements in contrast between properties of the phases. In addition to structural changes, we explore how large changes in the thermal and mechanical properties occur upon incorporation of the additives. Generalization of this additive-induced ordering strategy to various block copolymers will be discussed.

  20. Radio outbursts in extragalactic sources

    NASA Astrophysics Data System (ADS)

    Kinzel, Wayne Morris

    Three aspects of the flux density variability of extragalactic radio sources were examined: millimeter wavelength short timescale variability, the spectral evolution of outbursts, and whether the outbursts are periodically spaced. Observations of extragalactic radio sources were conducted using the Five College Radio Astronomy Observatory between January and June 1985 at 88.2 GHz and during June and July 1985 at 40.0 GHz. Many of the sources exhibited significant flux density variations during the observing span. In addition, the most rapid variations observed were comparable with those reported in previous works. Two sources, 0355+50 and OJ287, both exhibited outbursts whose rise and fall timescales were less than a month. An anomalous flux density dropout was observed in 3C446 and was interpreted as an occultation event. Data at five frequencies between 2.7 and 89.6 GHz from the Dent-Balonek monitoring program were used to investigate the spectral evolution of eight outbursts. Outburst profile fitting was used to deconvolve the individual outbursts from one another at each frequency. The fit profiles were used to generate multiple epoch spectra to investigate the evolution of the outbursts. A phase residual minimization method was used to examine four sources for periodic behavior.

  1. Integrating multiple data sources for malware classification

    DOEpatents

    Anderson, Blake Harrell; Storlie, Curtis B; Lane, Terran

    2015-04-28

    Disclosed herein are representative embodiments of tools and techniques for classifying programs. According to one exemplary technique, at least one graph representation of at least one dynamic data source of at least one program is generated. Also, at least one graph representation of at least one static data source of the at least one program is generated. Additionally, at least using the at least one graph representation of the at least one dynamic data source and the at least one graph representation of the at least one static data source, the at least one program is classified.

  2. 7 CFR 1944.686 - Additional grants.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 13 2011-01-01 2009-01-01 true Additional grants. 1944.686 Section 1944.686...) PROGRAM REGULATIONS (CONTINUED) HOUSING Housing Preservation Grants § 1944.686 Additional grants. An additional HPG grant may be made when the grantee has achieved or nearly achieved the goals established...

  3. 7 CFR 1944.545 - Additional grants.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 13 2013-01-01 2013-01-01 false Additional grants. 1944.545 Section 1944.545...) PROGRAM REGULATIONS (CONTINUED) HOUSING Technical and Supervisory Assistance Grants § 1944.545 Additional grants. An additional grant may be made to an applicant that has previously received a TSA grant and...

  4. 7 CFR 1944.545 - Additional grants.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 13 2011-01-01 2009-01-01 true Additional grants. 1944.545 Section 1944.545...) PROGRAM REGULATIONS (CONTINUED) HOUSING Technical and Supervisory Assistance Grants § 1944.545 Additional grants. An additional grant may be made to an applicant that has previously received a TSA grant and...

  5. 7 CFR 1944.686 - Additional grants.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 13 2013-01-01 2013-01-01 false Additional grants. 1944.686 Section 1944.686...) PROGRAM REGULATIONS (CONTINUED) HOUSING Housing Preservation Grants § 1944.686 Additional grants. An additional HPG grant may be made when the grantee has achieved or nearly achieved the goals established...

  6. 7 CFR 1944.545 - Additional grants.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 13 2010-01-01 2009-01-01 true Additional grants. 1944.545 Section 1944.545...) PROGRAM REGULATIONS (CONTINUED) HOUSING Technical and Supervisory Assistance Grants § 1944.545 Additional grants. An additional grant may be made to an applicant that has previously received a TSA grant and...

  7. 10 CFR 55.7 - Additional requirements.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 2 2010-01-01 2010-01-01 false Additional requirements. 55.7 Section 55.7 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) OPERATORS' LICENSES General Provisions § 55.7 Additional requirements. The Commission may, by rule, regulation, or order, impose upon any licensee such requirements, in addition...

  8. Polymeric Additives For Graphite/Epoxy Composites

    NASA Technical Reports Server (NTRS)

    Kourtides, D. A.; Nir, Z.

    1990-01-01

    Report describes experimental studies of properties of several graphite/epoxy composites containing polymeric additives as flexibilizing or toughening agents. Emphasizes effects of brominated polymeric additives (BPA's) with or without carboxy-terminated butadiene acrylonitrile rubber. Reviews effects of individual and combined additives on fracture toughnesses, environmental stabilities, hot/wet strengths, thermomechanical behaviors, and other mechanical properties of composites.

  9. 10 CFR 55.7 - Additional requirements.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 2 2014-01-01 2014-01-01 false Additional requirements. 55.7 Section 55.7 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) OPERATORS' LICENSES General Provisions § 55.7 Additional requirements. The Commission may, by rule, regulation, or order, impose upon any licensee such requirements, in addition...

  10. 14 CFR 27.927 - Additional tests.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Additional tests. 27.927 Section 27.927... STANDARDS: NORMAL CATEGORY ROTORCRAFT Powerplant Rotor Drive System § 27.927 Additional tests. (a) Any additional dynamic, endurance, and operational tests, and vibratory investigations necessary to...

  11. 14 CFR 29.927 - Additional tests.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Additional tests. 29.927 Section 29.927... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Rotor Drive System § 29.927 Additional tests. (a) Any additional dynamic, endurance, and operational tests, and vibratory investigations necessary to...

  12. 14 CFR 27.927 - Additional tests.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Additional tests. 27.927 Section 27.927... STANDARDS: NORMAL CATEGORY ROTORCRAFT Powerplant Rotor Drive System § 27.927 Additional tests. (a) Any additional dynamic, endurance, and operational tests, and vibratory investigations necessary to...

  13. 14 CFR 27.927 - Additional tests.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Additional tests. 27.927 Section 27.927... STANDARDS: NORMAL CATEGORY ROTORCRAFT Powerplant Rotor Drive System § 27.927 Additional tests. (a) Any additional dynamic, endurance, and operational tests, and vibratory investigations necessary to...

  14. 14 CFR 29.927 - Additional tests.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Additional tests. 29.927 Section 29.927... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Rotor Drive System § 29.927 Additional tests. (a) Any additional dynamic, endurance, and operational tests, and vibratory investigations necessary to...

  15. 14 CFR 29.927 - Additional tests.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Additional tests. 29.927 Section 29.927... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Powerplant Rotor Drive System § 29.927 Additional tests. (a) Any additional dynamic, endurance, and operational tests, and vibratory investigations necessary to...

  16. 17 CFR 48.10 - Additional contracts.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 17 Commodity and Securities Exchanges 2 2014-04-01 2014-04-01 false Additional contracts. 48.10...) REGISTRATION OF FOREIGN BOARDS OF TRADE § 48.10 Additional contracts. (a) Generally. A registered foreign board of trade that wishes to make an additional futures, option or swap contract available for trading...

  17. 17 CFR 48.10 - Additional contracts.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 17 Commodity and Securities Exchanges 1 2013-04-01 2013-04-01 false Additional contracts. 48.10... FOREIGN BOARDS OF TRADE § 48.10 Additional contracts. (a) Generally. A registered foreign board of trade that wishes to make an additional futures, option or swap contract available for trading by...

  18. 12 CFR 615.5460 - Additional provisions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 12 Banks and Banking 6 2010-01-01 2010-01-01 false Additional provisions. 615.5460 Section 615.5460 Banks and Banking FARM CREDIT ADMINISTRATION FARM CREDIT SYSTEM FUNDING AND FISCAL AFFAIRS, LOAN... Additional provisions. (a) Additional requirements. In any case or any class of cases arising under...

  19. 46 CFR 355.5 - Additional material.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 8 2012-10-01 2012-10-01 false Additional material. 355.5 Section 355.5 Shipping... STATES CITIZENSHIP § 355.5 Additional material. If additional material is determined to be essential to clarify or support the evidence of U.S. citizenship, such material shall be furnished by...

  20. 7 CFR 1944.545 - Additional grants.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 13 2012-01-01 2012-01-01 false Additional grants. 1944.545 Section 1944.545...) PROGRAM REGULATIONS (CONTINUED) HOUSING Technical and Supervisory Assistance Grants § 1944.545 Additional grants. An additional grant may be made to an applicant that has previously received a TSA grant and...

  1. 7 CFR 1944.686 - Additional grants.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 13 2012-01-01 2012-01-01 false Additional grants. 1944.686 Section 1944.686...) PROGRAM REGULATIONS (CONTINUED) HOUSING Housing Preservation Grants § 1944.686 Additional grants. An additional HPG grant may be made when the grantee has achieved or nearly achieved the goals established...

  2. 7 CFR 1944.545 - Additional grants.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 13 2014-01-01 2013-01-01 true Additional grants. 1944.545 Section 1944.545...) PROGRAM REGULATIONS (CONTINUED) HOUSING Technical and Supervisory Assistance Grants § 1944.545 Additional grants. An additional grant may be made to an applicant that has previously received a TSA grant and...

  3. 7 CFR 1944.686 - Additional grants.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 13 2014-01-01 2013-01-01 true Additional grants. 1944.686 Section 1944.686...) PROGRAM REGULATIONS (CONTINUED) HOUSING Housing Preservation Grants § 1944.686 Additional grants. An additional HPG grant may be made when the grantee has achieved or nearly achieved the goals established...

  4. 46 CFR 355.5 - Additional material.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 8 2014-10-01 2014-10-01 false Additional material. 355.5 Section 355.5 Shipping... STATES CITIZENSHIP § 355.5 Additional material. If additional material is determined to be essential to clarify or support the evidence of U.S. citizenship, such material shall be furnished by...

  5. 46 CFR 355.5 - Additional material.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 8 2013-10-01 2013-10-01 false Additional material. 355.5 Section 355.5 Shipping... STATES CITIZENSHIP § 355.5 Additional material. If additional material is determined to be essential to clarify or support the evidence of U.S. citizenship, such material shall be furnished by...

  6. 46 CFR 355.5 - Additional material.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 8 2011-10-01 2011-10-01 false Additional material. 355.5 Section 355.5 Shipping... STATES CITIZENSHIP § 355.5 Additional material. If additional material is determined to be essential to clarify or support the evidence of U.S. citizenship, such material shall be furnished by...

  7. 5 CFR 841.1006 - Additional provisions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 5 Administrative Personnel 2 2010-01-01 2010-01-01 false Additional provisions. 841.1006 Section....1006 Additional provisions. These additional provisions are also binding on the State and OPM: (a) A... will issue an accounting. If the State finds this accounting unacceptable, it may then and only...

  8. 5 CFR 831.1905 - Additional provisions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 5 Administrative Personnel 2 2010-01-01 2010-01-01 false Additional provisions. 831.1905 Section... (CONTINUED) RETIREMENT State Income Tax Withholding § 831.1905 Additional provisions. These additional provisions are also binding on the State and OPM: (a) A request or revocation is effective when processed...

  9. Volume 2 - Point Sources

    EPA Pesticide Factsheets

    Point source emission reference materials from the Emissions Inventory Improvement Program (EIIP). Provides point source guidance on planning, emissions estimation, data collection, inventory documentation and reporting, and quality assurance/quality contr

  10. Nonpoint Source: Forestry

    EPA Pesticide Factsheets

    Sources of nonpoint source (NPS) pollution associated with forestry activities include removal of streamside vegetation, road construction and use, timber harvesting, and mechanical preparation for the planting of trees. Information resources.

  11. European Spallation Source

    NASA Astrophysics Data System (ADS)

    Eshraqi, Mohammad; McGinnis, David; Lindroos, Mats

    The following sections are included: * Neutron usage and historical background * Spallation * History of spallation sources * The ESS facility * The ESS linac * Beam physics * The front-end and the normal conducting linac * Superconducting linac * RF sources * Summary * References

  12. Source Water Quality Monitoring

    EPA Science Inventory

    Presentation will provide background information on continuous source water monitoring using online toxicity monitors and cover various tools available. Conceptual and practical aspects of source water quality monitoring will be discussed.

  13. Optical Characteristics of Astrometric Radio Sources OCARS

    NASA Astrophysics Data System (ADS)

    Malkin, Z.

    2013-04-01

    In this paper, the current status of the catalog of Optical Characteristics of Astrometric Radio Sources OCARS is presented. The catalog includes radio sources observed in various astrometric and geodetic VLBI programs in 1979-2012. For these sources the physical object type, redshift and visual or infrared magnitude is given when available. Detailed comments are provided when some problems with published data were encountered. Since the first version created in December 2007, the catalog is continuously developed and expanded in respect to inclusion of new radio sources and addition of new or correction of old astrophysical data. Several sources of information are used for OCARS. The main of them are the NASA/IPAC Extragalactic Database (NED) and SIMBAD astronomical databases. Besides several astronomical journals and arXiv depository are regularly monitored, so that new data is included in OCARS just after publication. The redshift for about 150 sources have been determined from dedicated optical spectroscopic observations. As of October 2012, OCARS catalog includes 7173 radio sources. 3898 sources have known redshift, and 4860 sources have known magnitude. In 2009, it was used as a supplement material to the ICRF2. The list of radio sources with a good observational history but lacking astrophysical information is provide for planning of optical observations of the most important astrometric sources. The OCARS catalog is updated, in average every several weeks and is available at http://www.gao.spb.ru/english/as/ac_vlbi/ocars.txt.

  14. Controlling NOx emission from industrial sources

    SciTech Connect

    Srivastava, R.K.; Nueffer, W.; Grano, D.; Khan, S.; Staudt, J.E.; Jozewicz, W.

    2005-07-01

    A number of regulatory actions focused on reducing NOx emissions from stationary combustion sources have been taken in the United States in the last decade. These actions include the Acid Rain NOx regulations, the Ozone Transport Commission's NOx Budget Program, and the NOx SIP Call rulemakings. In addition to these regulations, the recent Interstate Air Quality Rulemaking proposal and other bills in the Congress are focusing on additional reductions of NOx. Industrial combustion sources accounted for about 18016 of NOx emissions in the United States in 2000 and constituted the second largest emitting source category within stationary sources, only behind electric utility sources. Based on these data, reduction of NOx emissions from industrial combustion sources is an important consideration in efforts undertaken to address the environmental concerns associated with NOx. This paper discusses primary and secondary NOx control technologies applicable to various major categories of industrial sources. The sources considered in this paper include large boilers, furnaces and fired heaters, combustion turbines, large IC engines, and cement kilns. For each source category considered in this paper, primary NOx controls are discussed first, followed by a discussion of secondary NOx controls.

  15. Familiarity in Source Memory

    PubMed Central

    Mollison, Matthew V.; Curran, Tim

    2012-01-01

    Familiarity and recollection are thought to be separate processes underlying recognition memory. Event-related potentials (ERPs) dissociate these processes, with an early (approximately 300–500 ms) frontal effect relating to familiarity (the FN400) and a later (500–800 ms) parietal old/new effect relating to recollection. It has been debated whether source information for a studied item (i.e., contextual associations from when the item was previously encountered) is only accessible through recollection, or whether familiarity can contribute to successful source recognition. It has been shown that familiarity can assist in perceptual source monitoring when the source attribute is an intrinsic property of the item (e.g., an object’s surface color), but few studies have examined its contribution to recognizing extrinsic source associations. Extrinsic source associations were examined in three experiments involving memory judgments for pictures of common objects. In Experiment 1, source information was spatial and results suggested that familiarity contributed to accurate source recognition: the FN400 ERP component showed a source accuracy effect, and source accuracy was above chance for items judged to only feel familiar. Source information in Experiment 2 was an extrinsic color association; source accuracy was at chance for familiar items and the FN400 did not differ between correct and incorrect source judgments. Experiment 3 replicated the results using a within-subjects manipulation of spatial vs. color source. Overall, the results suggest that familiarity’s contribution to extrinsic source monitoring depends on the type of source information being remembered. PMID:22789677

  16. 78 FR 77105 - Procurement List; Proposed Addition

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-12-20

    ... Defense, National Geospatial- Intelligence Agency, Arnold, MO Barry S. Lineback, Director, Business... Geospatial-Intelligence Agency, NGA Campus West, 3200 S 2nd Street, St. Louis, MO NPAs: ServiceSource,...

  17. 75 FR 33269 - Procurement List; Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-11

    ...: Product Wooden Trunk Locker NSN: 8460-00-243-3234. NPA: Employment Source, Inc., Fayetteville, NC... subcontract forever if the commercial portion of the trunk locker requirement is added to the PL. Based on...

  18. 78 FR 25971 - Procurement List, Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-03

    ..., Navy Operational Support Center Fort Schuyler-Bronx, 4 Pennyfield Avenue, Bronx, NY NPAs: Work, Incorporated, Dorchester, MA (Prime), The Corporate Source, Inc., New York, NY (Subcontractor), Navy..., MA (Prime), Easter Seals Capital Region & Eastern Connecticut, Inc., Windsor, CT...

  19. Investigating Primary Source Literacy

    ERIC Educational Resources Information Center

    Archer, Joanne; Hanlon, Ann M.; Levine, Jennie A.

    2009-01-01

    Primary source research requires students to acquire specialized research skills. This paper presents results from a user study testing the effectiveness of a Web guide designed to convey the concepts behind "primary source literacy". The study also evaluated students' strengths and weaknesses when conducting primary source research. (Contains 3…

  20. Extragalactic Radio Sources

    ERIC Educational Resources Information Center

    Kellerman, Kenneth I.

    1973-01-01

    Discusses new problems arising from the growing observational data through radio telescope arrays, involving the origin of radio sources, apparent superluminal velocities, conversion of radio sources to relativistic particles, and the nature of compact opaque and extended transparent sources. New physics may be needed to answer these cosmological…

  1. Comprehensive Study of Carbonaceous Species in Arctic Snow: from Snow Type to Carbon Sources and Sinks in the Snowpack

    NASA Astrophysics Data System (ADS)

    Voisin, D.; Cozic, J.; Houdier, S.; Barret, M.; Jaffrezo, J. L.; King, M. D.; Beine, H. J.; Domine, F.

    2012-04-01

    Carbonaceous species play critical roles in the interaction of snow with the overlying atmosphere. Elemental or Black Carbon strongly increases solar energy uptake and snow melt, therefore influencing the snow-climate feedback loop. Carbonyls and complex organic molecules such as Humic Like Substances also absorb UV and visible light, therefore influencing photochemistry and light penetration depths in the snowpack. It has been proposed that some of those complex organic molecules, acting as electron donors in photochemical reactions might change the photolysis paths of nitric acid from NO / NO2 to HONO. Yet, comprehensive investigations of the organic matter in arctic snowpack are scarce, and often limited to a few specific species. Such a comprehensive representation of carbonaceous species in Arctic snow is the focus of the present work, lead during the OASIS field campaign in Barrow and focuses on major classes of carbonaceous species, defined operationally: Elemental Carbon (EC), which is close to BC; Water Insoluble Organic Carbon (WInOC); Dissolved Organic Carbon (DOC), which altogether represent the Total Carbon Content (TCC) of the snowpack. Among DOC species, we will more particularly focus on HUmic LIke Substances (HULIS), C2 - C5 dicarboxylic acids and short chain aldehydes, as these compounds are most particularly involved in snow photochemistry, especially HULIS, whose optical properties (UV-Vis absorbance) are measured and discussed. In order to link observed concentrations to physico-chemical processes in the snow pack, we use snow type as a morphological marker of those processes and of the snowpack's history. Similarly, as the different classes of compounds measured are differently affected by the physical processes that lead the transformation of the snowpack, they can be used to probe into those processes. This strategy enables us to discuss in a common framework physical and chemical processes affecting carbonaceous species and the snowpack

  2. Dose effect in the wood plastic composite formation in the presence of additives and co-additives

    NASA Astrophysics Data System (ADS)

    Khan, Mubarak A.; Ali, K. M. Idriss

    1994-10-01

    Wood plastic composite (WPC) formation was studied with simul wood and butylmethacrylate (BMA) at different compositions with swelling solvent methanol in the presence of a set of multifunctional acrylate monomer additives like N-vinyl Pyrrolidone (NVP), tripropylene glycol diacrylate (TPGDA) and trimethylol propane triacrylate (TMPTA) at a different doses between 1 and 3 Mrad using Co 60 gamma source. This was further investigated using another set of additives chosen from oligomers such as epoxy acrylate (EA), urethane acrylate (UA) and polyester acrylate (PEA). TMPTA yielded the highest polymer loading at relatively low dose (2 Mrad). Effect of co-additives like sulfuric acid (H + ions), copper sulphate (Cu 2+ ions) and urea was investigated in these series. Tensile strength (TS) of the composites were determined and the highest TS values were obtained with the composite produced in presence of urea.

  3. DC source assemblies

    DOEpatents

    Campbell, Jeremy B; Newson, Steve

    2013-02-26

    Embodiments of DC source assemblies of power inverter systems of the type suitable for deployment in a vehicle having an electrically grounded chassis are provided. An embodiment of a DC source assembly comprises a housing, a DC source disposed within the housing, a first terminal, and a second terminal. The DC source also comprises a first capacitor having a first electrode electrically coupled to the housing, and a second electrode electrically coupled to the first terminal. The DC source assembly further comprises a second capacitor having a first electrode electrically coupled to the housing, and a second electrode electrically coupled to the second terminal.

  4. Nitrogen as a friendly addition to steel

    SciTech Connect

    Rawers, J.C.

    2006-01-01

    Interstitial alloying with nitrogen or carbon is a common means of enhancing properties of iron-based alloys. Interstitial nitrogen addition to fcc-phase Fe-Cr-Mn/Ni alloys results in improved mechanical properties, whereas addition of carbon can result in the formation of unwanted carbides. Carbon addition to low alloy, bcc-phase iron alloys significantly improves strength through the formation of carbides, whereas addition of nitrogen in bcc-phase iron alloys can result in porous casting and reduced mechanical properties. This study will show that alloying iron-based alloys with both nitrogen and carbon can produce positive results. Nitrogen addition to Fe-C and Fe-Cr-C alloys, and both nitrogen and nitrogen-carbon additions to Fe-Cr-Mn/Ni alloys altered the microstructure, improved mechanical properties, increased hardness, and reduced wear by stabilizing the fcc-phase and altering (possibly eliminating) precipitate formation.

  5. The Herschel Point Source Catalogue

    NASA Astrophysics Data System (ADS)

    Marton, Gabor; Schulz, Bernhard; Altieri, Bruno; Calzoletti, Luca; Kiss, Csaba; Lim, Tanya; Lu, Nanyao; Paladini, Roberta; Papageorgiou, Andreas; Pearson, Chris; Rector, John; Shupe, David; Valtchanov, Ivan; Verebélyi, Erika; Xu, Kevin

    2015-08-01

    The Herschel Space Observatory was the fourth cornerstone mission in the European Space Agency (ESA) science programme with excellent broad band imaging capabilities in the submillimetre and far-infrared part of the spectrum. Although the spacecraft finished its observations in 2013, it left a large legacy dataset that is far from having been fully scrutinized and still has potential for new scientific discoveries. This is specifically true for the photometric observations of the PACS and SPIRE instruments that scanned >10% of the sky at 70, 100, 160, 250, 350 and 500 microns. Some source catalogs have already been produced by individual observing programs, but there are many observations that would never be analyzed for their full source content. To maximize the science return of the SPIRE and PACS data sets, our international team of instrument experts is in the process of building the Herschel Point Source Catalog (HPSC) from all scan map observations. Our homogeneous source extraction enables a systematic and unbiased comparison of sensitivity across the different Herschel fields that single programs will generally not be able to provide. The extracted point sources will contain individual YSOs of our Galaxy, unresolved YSO clusters in resolved nearby galaxies and unresolved galaxies of the local and distant Universe that are related to star formation. Such a huge dataset will help scientists better understand the evolution from interstellar clouds to individual stars. Furthermore the analysis of stellar clusters and the star formation on galactic scales will add more details to the understanding of star formation laws through time.We present our findings on comparison of different source detection and photometric tools. First results of the extractions are shown along with the description of our pipelines and catalogue entries. We also provide an additional science product, the structure noise map, that is used for the quality assessment of the catalogue in

  6. Neuromagnetic source reconstruction

    SciTech Connect

    Lewis, P.S.; Mosher, J.C.; Leahy, R.M.

    1994-12-31

    In neuromagnetic source reconstruction, a functional map of neural activity is constructed from noninvasive magnetoencephalographic (MEG) measurements. The overall reconstruction problem is under-determined, so some form of source modeling must be applied. We review the two main classes of reconstruction techniques-parametric current dipole models and nonparametric distributed source reconstructions. Current dipole reconstructions use a physically plausible source model, but are limited to cases in which the neural currents are expected to be highly sparse and localized. Distributed source reconstructions can be applied to a wider variety of cases, but must incorporate an implicit source, model in order to arrive at a single reconstruction. We examine distributed source reconstruction in a Bayesian framework to highlight the implicit nonphysical Gaussian assumptions of minimum norm based reconstruction algorithms. We conclude with a brief discussion of alternative non-Gaussian approachs.

  7. Cincinnati Big Area Additive Manufacturing (BAAM)

    SciTech Connect

    Duty, Chad E.; Love, Lonnie J.

    2015-03-04

    Oak Ridge National Laboratory (ORNL) worked with Cincinnati Incorporated (CI) to demonstrate Big Area Additive Manufacturing which increases the speed of the additive manufacturing (AM) process by over 1000X, increases the size of parts by over 10X and shows a cost reduction of over 100X. ORNL worked with CI to transition the Big Area Additive Manufacturing (BAAM) technology from a proof-of-principle (TRL 2-3) demonstration to a prototype product stage (TRL 7-8).

  8. Item Strength Influences Source Confidence and Alters Source Memory zROC Slopes

    ERIC Educational Resources Information Center

    Starns, Jeffrey J.; Ksander, John C.

    2016-01-01

    Increasing the number of study trials creates a crossover pattern in source memory zROC slopes; that is, the slope is either below or above 1 depending on which source receives stronger learning. This pattern can be produced if additional learning affects memory processes such as the relative contribution of recollection and familiarity to source…

  9. 42 CFR 67.22 - Additional conditions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... AGENCY FOR HEALTH CARE POLICY AND RESEARCH GRANTS AND CONTRACTS Research Grants for Health Services Research, Evaluation, Demonstration, and Dissemination Projects § 67.22 Additional conditions....

  10. Selection of color additives: a regulatory view.

    PubMed

    Kumar, Anuj; Dureja, Harish; Madan, Anil K

    2012-01-01

    Color additives have a unique place in the categories of the excipients. However, most of the color additives are complex heterogeneous organic compounds. In pharmaceuticals, colors are used in various oral (solid, liquid) and topical dosage form. Different regulatory authorities have their own specific set of regulation for registration, approval, and control of color additives. However, at this time of globalization, selection of appropriate color is not an easy task when a company wants to sale its product in many countries. In this article, the authors have explored various important factors which should be considered in the selection of color additives.

  11. Allergic and immunologic reactions to food additives.

    PubMed

    Gultekin, Fatih; Doguc, Duygu Kumbul

    2013-08-01

    For centuries, food additives have been used for flavouring, colouring and extension of the useful shelf life of food, as well as the promotion of food safety. During the last 20 years, the studies implicating the additives contained in foods and medicine as a causative factor of allergic reactions have been proliferated considerably. In this review, we aimed to overview all of the food additives which were approved to consume in EU and find out how common and serious allergic reactions come into existence following the consuming of food additives.

  12. Classification of additives for organic photovoltaic devices.

    PubMed

    Machui, Florian; Maisch, Philipp; Burgués-Ceballos, Ignasi; Langner, Stefan; Krantz, Johannes; Ameri, Tayebeh; Brabec, Christoph J

    2015-04-27

    The use of additives to improve the performance of organic photovoltaic cells has been intensely researched in recent years. However, so far, no system has been reported for the classification of additives and their functions. In this report, a system for classifying additives according to the fundamental mechanism by which they influence microstructure formation for P3HT:PCBM is suggested. The major parameters used for their classification are solubility and drying kinetics. Both are discussed in detail and their consequences on processing are analyzed. Furthermore, a general mechanism to classify the impact of additives on structure formation is suggested and discussed for different materials relevant to organic photovoltaic devices.

  13. Strategy for Texture Management in Metals Additive Manufacturing

    NASA Astrophysics Data System (ADS)

    Kirka, M. M.; Lee, Y.; Greeley, D. A.; Okello, A.; Goin, M. J.; Pearce, M. T.; Dehoff, R. R.

    2017-03-01

    Additive manufacturing (AM) technologies have long been recognized for their ability to fabricate complex geometric components directly from models conceptualized through computers, allowing for complicated designs and assemblies to be fabricated at lower costs, with shorter time to market, and improved function. Lacking behind the design complexity aspect is the ability to fully exploit AM processes for control over texture within AM components. Currently, standard heat-fill strategies utilized in AM processes result in largely columnar grain structures. Proposed in this work is a point heat source fill for the electron beam melting (EBM) process through which the texture in AM materials can be controlled. Through this point heat source strategy, the ability to form either columnar or equiaxed grain structures upon solidification through changes in the process parameters associated with the point heat source fill is demonstrated for the nickel-base superalloy, Inconel 718. Mechanically, the material is demonstrated to exhibit either anisotropic properties for the columnar-grained material fabricated through using the standard raster scan of the EBM process or isotropic properties for the equiaxed material fabricated using the point heat source fill.

  14. Influence of carbon sources on nutrient removal in A(2)/O-MBRs: Availability assessment of internal carbon source.

    PubMed

    Xu, Rongle; Fan, Yaobo; Wei, Yuansong; Wang, Yawei; Luo, Nan; Yang, Min; Yuan, Xing; Yu, Rong

    2016-10-01

    Both internal carbon source and some external carbon sources were used to improve the nutrient removal in Anaerobic-Anoxic-Oxic-Membrane Bioreactor (A(2)/O-MBRs), and their technical and cost analysis was investigated. The experimental results showed that the nutrient removals were improved by all the carbon source additions. The total nitrogen and phosphorus removal efficiency were higher in the experiments with external carbon source additions than that with internal carbon source addition. It was found that pathways of nitrogen and phosphorus transform were different dependent on different carbon source additions by the mass balance analysis. With external carbon source addition, the simultaneous nitrification and denitrification occurred in aerobic zone, and the P-uptake in aerobic phase was evident. Therefore, with addition of C-MHP (internal carbon source produced from sludge pretreatment by microwave-H2O2 process), the denitrification and phosphorus-uptake in anoxic zone was notable. Cost analysis showed that the unit nitrogen removal costs were 57.13CNY/kg N of C-acetate addition and 54.48CNY/kgN of C-MHP addition, respectively. The results indicated that the C-MHP has a good technical and economic feasibility to substitute external carbon sources partially for nutrient removal.

  15. Novel electrolyte additives to enhance zinc electrode cycle life

    SciTech Connect

    Doddapaneni, N.; Ingersoll, D.

    1995-11-01

    Electrochemical power sources that utilize zinc electrodes possess many advantages. Zinc is abundantly available, benign, inexpensive, stable over a wide operating temperature range, and has a high oxidation potential. In spite of these advantageous characteristics, rechargeable electrochemical systems based on zinc chemistry have not found widespread use. The major disadvantages of zinc electrodes are that they have limited cycle life due to zinc slumping and zinc electrode shape changes in alkaline solutions resulting from the solubility of zincate (Zn(OH){sub 4}{sup 2-}) in these solutions. As a result, premature cell failure often results due to cell shorting caused by dendritic growth as well as zinc slumping. In this paper we describe the chemical and physical characteristics of electrolyte solutions employing additives, particularly for zinc based electrochemical systems. These electrolytes are prepared using the alkali metal salts of 1,3,5-phenyltrisulfonic acid in combination with potassium hydroxide. The alkali metal salts of the acid possess good thermal stability, good ionic conductivity, and have a wide electrochemical voltage window in aqueous systems. With these electrolyte solutions improved cycle life was achieved in Zn/NiOOH and Zn/AgO. Improved cycle life with this additive is attributed to decreased zincate solubility, resulting in reduced zinc slumping and electrode shape changes. In addition, increased shelf-life and reduced self-discharge were also observed in many alkaline power sources.

  16. 26 CFR 31.3302(b)-2 - Proof of additional credit under section 3302(b).

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 15 2010-04-01 2010-04-01 false Proof of additional credit under section 3302(b). 31.3302(b)-2 Section 31.3302(b)-2 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) EMPLOYMENT TAXES AND COLLECTION OF INCOME TAX AT SOURCE EMPLOYMENT TAXES AND COLLECTION OF INCOME TAX AT SOURCE...

  17. 49 CFR 1108.12 - Additional matters.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 8 2010-10-01 2010-10-01 false Additional matters. 1108.12 Section 1108.12 Transportation Other Regulations Relating to Transportation (Continued) SURFACE TRANSPORTATION BOARD, DEPARTMENT... JURISDICTION OF THE SURFACE TRANSPORTATION BOARD § 1108.12 Additional matters. Where an arbitration demand...

  18. 49 CFR 1108.12 - Additional matters.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 8 2012-10-01 2012-10-01 false Additional matters. 1108.12 Section 1108.12 Transportation Other Regulations Relating to Transportation (Continued) SURFACE TRANSPORTATION BOARD, DEPARTMENT... JURISDICTION OF THE SURFACE TRANSPORTATION BOARD § 1108.12 Additional matters. Where an arbitration demand...

  19. 49 CFR 1108.12 - Additional matters.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 8 2011-10-01 2011-10-01 false Additional matters. 1108.12 Section 1108.12 Transportation Other Regulations Relating to Transportation (Continued) SURFACE TRANSPORTATION BOARD, DEPARTMENT... JURISDICTION OF THE SURFACE TRANSPORTATION BOARD § 1108.12 Additional matters. Where an arbitration demand...

  20. 15 CFR 990.66 - Additional considerations.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 15 Commerce and Foreign Trade 3 2010-01-01 2010-01-01 false Additional considerations. 990.66 Section 990.66 Commerce and Foreign Trade Regulations Relating to Commerce and Foreign Trade (Continued... NATURAL RESOURCE DAMAGE ASSESSMENTS Restoration Implementation Phase § 990.66 Additional...

  1. 10 CFR 2.605 - Additional considerations.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Additional considerations. 2.605 Section 2.605 Energy NUCLEAR REGULATORY COMMISSION RULES OF PRACTICE FOR DOMESTIC LICENSING PROCEEDINGS AND ISSUANCE OF ORDERS... Permit § 2.605 Additional considerations. (a) The Commission will not conduct more than one review...

  2. 10 CFR 2.625 - Additional considerations.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 1 2010-01-01 2010-01-01 false Additional considerations. 2.625 Section 2.625 Energy NUCLEAR REGULATORY COMMISSION RULES OF PRACTICE FOR DOMESTIC LICENSING PROCEEDINGS AND ISSUANCE OF ORDERS... License Under 10 Cfr Part 52 § 2.625 Additional considerations. (a) The Commission will not conduct...

  3. 42 CFR 52d.9 - Additional conditions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Additional conditions. 52d.9 Section 52d.9 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS NATIONAL CANCER INSTITUTE CLINICAL CANCER EDUCATION PROGRAM § 52d.9 Additional conditions. The Director, NCI, may with respect to...

  4. 42 CFR 52d.9 - Additional conditions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Additional conditions. 52d.9 Section 52d.9 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS NATIONAL CANCER INSTITUTE CLINICAL CANCER EDUCATION PROGRAM § 52d.9 Additional conditions. The Director, NCI, may with respect to...

  5. 42 CFR 52d.9 - Additional conditions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Additional conditions. 52d.9 Section 52d.9 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS NATIONAL CANCER INSTITUTE CLINICAL CANCER EDUCATION PROGRAM § 52d.9 Additional conditions. The Director, NCI, may with respect to...

  6. 42 CFR 52d.9 - Additional conditions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Additional conditions. 52d.9 Section 52d.9 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS NATIONAL CANCER INSTITUTE CLINICAL CANCER EDUCATION PROGRAM § 52d.9 Additional conditions. The Director, NCI, may with respect to...

  7. 42 CFR 52d.9 - Additional conditions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Additional conditions. 52d.9 Section 52d.9 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS NATIONAL CANCER INSTITUTE CLINICAL CANCER EDUCATION PROGRAM § 52d.9 Additional conditions. The Director, NCI, may with respect to...

  8. 43 CFR 3154.2 - Additional bonding.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false Additional bonding. 3154.2 Section 3154.2 Public Lands: Interior Regulations Relating to Public Lands (Continued) BUREAU OF LAND MANAGEMENT... Requirements § 3154.2 Additional bonding. The authorized officer may increase the amount of any bond that...

  9. Asthma and anaphylactoid reactions to food additives.

    PubMed Central

    Tarlo, S. M.; Sussman, G. L.

    1993-01-01

    Presumed allergic reactions to hidden food additives are both controversial and important. Clinical manifestations include asthma, urticaria, angioedema, and anaphylactic-anaphylactoid events. Most adverse reactions are caused by just a few additives, such as sulfites and monosodium glutamate. Diagnosis is suspected from the history and confirmed by specific challenge. The treatment is specific avoidance. PMID:8499792

  10. 42 CFR 52e.9 - Additional conditions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Additional conditions. 52e.9 Section 52e.9 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS NATIONAL HEART, LUNG, AND BLOOD INSTITUTE GRANTS FOR PREVENTION AND CONTROL PROJECTS § 52e.9 Additional conditions. The...

  11. 42 CFR 52e.9 - Additional conditions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Additional conditions. 52e.9 Section 52e.9 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS NATIONAL HEART, LUNG, AND BLOOD INSTITUTE GRANTS FOR PREVENTION AND CONTROL PROJECTS § 52e.9 Additional conditions. The...

  12. 42 CFR 52e.9 - Additional conditions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Additional conditions. 52e.9 Section 52e.9 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS NATIONAL HEART, LUNG, AND BLOOD INSTITUTE GRANTS FOR PREVENTION AND CONTROL PROJECTS § 52e.9 Additional conditions. The...

  13. Fuel compositions containing deposit control additives

    SciTech Connect

    Lilburn, J.E.

    1980-11-18

    Fuel compositions are provided which contain a deposit control additive. The deposit control additive is produced by reacting a hydrocarbylpoly(oxyalkylene) alcohol with excess phosgene and an excess amount of certain polyamines. The product comprises hydrocarbylpoly(oxyalkylene) ureylene carbamates.

  14. 42 CFR 52a.9 - Additional conditions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Additional conditions. 52a.9 Section 52a.9 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS NATIONAL INSTITUTES OF HEALTH CENTER GRANTS § 52a.9 Additional conditions. The Director may, with respect to any grant...

  15. 42 CFR 52b.13 - Additional conditions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Additional conditions. 52b.13 Section 52b.13 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS NATIONAL INSTITUTES OF HEALTH CONSTRUCTION GRANTS § 52b.13 Additional conditions. The Director may with respect to any...

  16. 42 CFR 52b.13 - Additional conditions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Additional conditions. 52b.13 Section 52b.13 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS NATIONAL INSTITUTES OF HEALTH CONSTRUCTION GRANTS § 52b.13 Additional conditions. The Director may with respect to any...

  17. 42 CFR 52a.9 - Additional conditions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Additional conditions. 52a.9 Section 52a.9 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS NATIONAL INSTITUTES OF HEALTH CENTER GRANTS § 52a.9 Additional conditions. The Director may, with respect to any grant...

  18. 42 CFR 52a.9 - Additional conditions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Additional conditions. 52a.9 Section 52a.9 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS NATIONAL INSTITUTES OF HEALTH CENTER GRANTS § 52a.9 Additional conditions. The Director may, with respect to any grant...

  19. 42 CFR 52a.9 - Additional conditions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Additional conditions. 52a.9 Section 52a.9 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS NATIONAL INSTITUTES OF HEALTH CENTER GRANTS § 52a.9 Additional conditions. The Director may, with respect to any grant...

  20. 42 CFR 52b.13 - Additional conditions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Additional conditions. 52b.13 Section 52b.13 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS NATIONAL INSTITUTES OF HEALTH CONSTRUCTION GRANTS § 52b.13 Additional conditions. The Director may with respect to any...

  1. 42 CFR 52b.13 - Additional conditions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Additional conditions. 52b.13 Section 52b.13 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS NATIONAL INSTITUTES OF HEALTH CONSTRUCTION GRANTS § 52b.13 Additional conditions. The Director may with respect to any...

  2. 42 CFR 52b.13 - Additional conditions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Additional conditions. 52b.13 Section 52b.13 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS NATIONAL INSTITUTES OF HEALTH CONSTRUCTION GRANTS § 52b.13 Additional conditions. The Director may with respect to any...

  3. 42 CFR 52a.9 - Additional conditions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Additional conditions. 52a.9 Section 52a.9 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS NATIONAL INSTITUTES OF HEALTH CENTER GRANTS § 52a.9 Additional conditions. The Director may, with respect to any grant...

  4. 42 CFR 52c.8 - Additional conditions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Additional conditions. 52c.8 Section 52c.8 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS MINORITY BIOMEDICAL RESEARCH SUPPORT PROGRAM § 52c.8 Additional conditions. The Secretary may with respect to any grant award...

  5. 42 CFR 52c.8 - Additional conditions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Additional conditions. 52c.8 Section 52c.8 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS MINORITY BIOMEDICAL RESEARCH SUPPORT PROGRAM § 52c.8 Additional conditions. The Secretary may with respect to any grant award...

  6. 42 CFR 52c.8 - Additional conditions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Additional conditions. 52c.8 Section 52c.8 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS MINORITY BIOMEDICAL RESEARCH SUPPORT PROGRAM § 52c.8 Additional conditions. The Secretary may with respect to any grant award...

  7. 42 CFR 52c.8 - Additional conditions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Additional conditions. 52c.8 Section 52c.8 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS MINORITY BIOMEDICAL RESEARCH SUPPORT PROGRAM § 52c.8 Additional conditions. The Secretary may with respect to any grant award...

  8. 42 CFR 52c.8 - Additional conditions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Additional conditions. 52c.8 Section 52c.8 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS MINORITY BIOMEDICAL RESEARCH SUPPORT PROGRAM § 52c.8 Additional conditions. The Secretary may with respect to any grant award...

  9. 77 FR 47823 - Procurement List; Proposed Addition

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-10

    ... Administration, New York, NY Coverage: A-List for the Total Government Requirement as aggregated by the General... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List; Proposed Addition AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Proposed Addition to the Procurement...

  10. 78 FR 45183 - Procurement List Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-26

    ... Services Administration, New York, NY. COVERAGE: A-List for the Total Government Requirement as aggregated... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List Additions AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Additions to the Procurement List. SUMMARY:...

  11. 11 CFR 9007.4 - Additional audits.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 11 Federal Elections 1 2010-01-01 2010-01-01 false Additional audits. 9007.4 Section 9007.4 Federal Elections FEDERAL ELECTION COMMISSION PRESIDENTIAL ELECTION CAMPAIGN FUND: GENERAL ELECTION FINANCING EXAMINATIONS AND AUDITS; REPAYMENTS § 9007.4 Additional audits. In accordance with 11 CFR...

  12. 11 CFR 9008.13 - Additional audits.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 11 Federal Elections 1 2014-01-01 2014-01-01 false Additional audits. 9008.13 Section 9008.13... Convention Committees § 9008.13 Additional audits. In accordance with 11 CFR 104.16(c), the Commission, pursuant to 11 CFR 111.10, may upon affirmative vote of four members conduct an audit and...

  13. 11 CFR 9007.4 - Additional audits.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 11 Federal Elections 1 2014-01-01 2014-01-01 false Additional audits. 9007.4 Section 9007.4... FINANCING EXAMINATIONS AND AUDITS; REPAYMENTS § 9007.4 Additional audits. In accordance with 11 CFR 104.16(c), the Commission, pursuant to 11 CFR 111.10, may upon affirmative vote of four members conduct an...

  14. 11 CFR 9008.13 - Additional audits.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 11 Federal Elections 1 2013-01-01 2012-01-01 true Additional audits. 9008.13 Section 9008.13... Convention Committees § 9008.13 Additional audits. In accordance with 11 CFR 104.16(c), the Commission, pursuant to 11 CFR 111.10, may upon affirmative vote of four members conduct an audit and...

  15. 11 CFR 9007.4 - Additional audits.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 11 Federal Elections 1 2013-01-01 2012-01-01 true Additional audits. 9007.4 Section 9007.4 Federal... EXAMINATIONS AND AUDITS; REPAYMENTS § 9007.4 Additional audits. In accordance with 11 CFR 104.16(c), the Commission, pursuant to 11 CFR 111.10, may upon affirmative vote of four members conduct an audit and...

  16. Developing Multiplicative Thinking from Additive Reasoning

    ERIC Educational Resources Information Center

    Tobias, Jennifer M.; Andreasen, Janet B.

    2013-01-01

    As students progress through elementary school, they encounter mathematics concepts that shift from additive to multiplicative situations (NCTM 2000). When they encounter fraction problems that require multiplicative thinking, they tend to incorrectly extend additive properties from whole numbers (Post et al. 1985). As a result, topics such as …

  17. 12 CFR 619.9010 - Additional security.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 7 2014-01-01 2014-01-01 false Additional security. 619.9010 Section 619.9010 Banks and Banking FARM CREDIT ADMINISTRATION FARM CREDIT SYSTEM DEFINITIONS § 619.9010 Additional security. Supplementary collateral to the primary security taken in connection with the loan....

  18. 12 CFR 619.9010 - Additional security.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 12 Banks and Banking 6 2011-01-01 2011-01-01 false Additional security. 619.9010 Section 619.9010 Banks and Banking FARM CREDIT ADMINISTRATION FARM CREDIT SYSTEM DEFINITIONS § 619.9010 Additional security. Supplementary collateral to the primary security taken in connection with the loan....

  19. 42 CFR 68.16 - Additional conditions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Additional conditions. 68.16 Section 68.16 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES FELLOWSHIPS, INTERNSHIPS, TRAINING NATIONAL INSTITUTES OF HEALTH (NIH) LOAN REPAYMENT PROGRAMS (LRPs) § 68.16 Additional conditions. (a)...

  20. 42 CFR 68.16 - Additional conditions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Additional conditions. 68.16 Section 68.16 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES FELLOWSHIPS, INTERNSHIPS, TRAINING NATIONAL INSTITUTES OF HEALTH (NIH) LOAN REPAYMENT PROGRAMS (LRPs) § 68.16 Additional conditions. (a)...

  1. 46 CFR 308.502 - Additional insurance.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 8 2013-10-01 2013-10-01 false Additional insurance. 308.502 Section 308.502 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION EMERGENCY OPERATIONS WAR RISK INSURANCE War Risk Cargo Insurance I-Introduction § 308.502 Additional insurance. The assured may place increased value...

  2. 46 CFR 308.502 - Additional insurance.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 8 2012-10-01 2012-10-01 false Additional insurance. 308.502 Section 308.502 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION EMERGENCY OPERATIONS WAR RISK INSURANCE War Risk Cargo Insurance I-Introduction § 308.502 Additional insurance. The assured may place increased value...

  3. 46 CFR 308.502 - Additional insurance.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 8 2014-10-01 2014-10-01 false Additional insurance. 308.502 Section 308.502 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION EMERGENCY OPERATIONS WAR RISK INSURANCE War Risk Cargo Insurance Introduction § 308.502 Additional insurance. The assured may place increased value...

  4. 77 FR 27737 - Procurement List Proposed Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-11

    ... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List Proposed Additions AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Proposed additions to the Procurement List... nonprofit agencies employing persons who are blind or have other severe disabilities. Comments Must...

  5. 77 FR 55195 - Procurement List; Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-07

    ... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List; Additions AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Additions to the Procurement List. SUMMARY: This... persons who are blind or have other severe disabilities. DATES: Effective Date: 10/8/2012....

  6. 78 FR 5423 - Procurement List; Proposed Additions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-25

    ... FROM PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List; Proposed Additions AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Proposed Additions to the... furnished by nonprofit agencies employing persons who are blind or have other severe disabilities....

  7. 77 FR 44220 - Procurement List; Proposed Addition

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-27

    ... PEOPLE WHO ARE BLIND OR SEVERELY DISABLED Procurement List; Proposed Addition AGENCY: Committee for Purchase From People Who Are Blind or Severely Disabled. ACTION: Proposed Addition to the Procurement List... nonprofit agency employing persons who are blind or have other severe disabilities. DATES: Comments Must...

  8. 42 CFR 59.12 - Additional conditions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Additional conditions. 59.12 Section 59.12 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS GRANTS FOR FAMILY PLANNING SERVICES Project Grants for Family Planning Services § 59.12 Additional conditions. The Secretary may,...

  9. 42 CFR 59.12 - Additional conditions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Additional conditions. 59.12 Section 59.12 Public Health PUBLIC HEALTH SERVICE, DEPARTMENT OF HEALTH AND HUMAN SERVICES GRANTS GRANTS FOR FAMILY PLANNING SERVICES Project Grants for Family Planning Services § 59.12 Additional conditions. The Secretary may,...

  10. 46 CFR 117.25 - Additional requirements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Additional requirements. 117.25 Section 117.25 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS CARRYING MORE THAN 150... General Provisions § 117.25 Additional requirements. (a) Each item of lifesaving equipment carried...

  11. 46 CFR 117.25 - Additional requirements.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Additional requirements. 117.25 Section 117.25 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS CARRYING MORE THAN 150... General Provisions § 117.25 Additional requirements. (a) Each item of lifesaving equipment carried...

  12. 46 CFR 117.25 - Additional requirements.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Additional requirements. 117.25 Section 117.25 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS CARRYING MORE THAN 150... General Provisions § 117.25 Additional requirements. (a) Each item of lifesaving equipment carried...

  13. The Additive Coloration of Alkali Halides

    ERIC Educational Resources Information Center

    Jirgal, G. H.; and others

    1969-01-01

    Describes the construction and use of an inexpensive, vacuum furnace designed to produce F-centers in alkali halide crystals by additive coloration. The method described avoids corrosion or contamination during the coloration process. Examination of the resultant crystals is discussed and several experiments using additively colored crystals are…

  14. 10 CFR 71.65 - Additional requirements.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 2 2010-01-01 2010-01-01 false Additional requirements. 71.65 Section 71.65 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) PACKAGING AND TRANSPORTATION OF RADIOACTIVE MATERIAL Package Approval Standards § 71.65 Additional requirements. The Commission may, by rule, regulation, or...

  15. 10 CFR 781.53 - Additional licenses.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 4 2013-01-01 2013-01-01 false Additional licenses. 781.53 Section 781.53 Energy DEPARTMENT OF ENERGY DOE PATENT LICENSING REGULATIONS Types of Licenses and Conditions for Licensing § 781.53... of Energy from granting additional nonexclusive, or exclusive, or partially exclusive licenses...

  16. 10 CFR 781.53 - Additional licenses.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 4 2014-01-01 2014-01-01 false Additional licenses. 781.53 Section 781.53 Energy DEPARTMENT OF ENERGY DOE PATENT LICENSING REGULATIONS Types of Licenses and Conditions for Licensing § 781.53... of Energy from granting additional nonexclusive, or exclusive, or partially exclusive licenses...

  17. 78 FR 22209 - Additional Synthetic Drug Testing

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-15

    ... COMMISSION 10 CFR Part 26 Additional Synthetic Drug Testing AGENCY: Nuclear Regulatory Commission. ACTION... NRC amend its Fitness for Duty program regulations to amend drug testing requirements to test for additional synthetic drugs currently not included in the regulations. The NRC determined that the...

  18. 31 CFR 354.10 - Additional provisions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... SERVICE, DEPARTMENT OF THE TREASURY BUREAU OF THE PUBLIC DEBT REGULATIONS GOVERNING BOOK-ENTRY SECURITIES OF THE STUDENT LOAN MARKETING ASSOCIATION (SALLIE MAE) § 354.10 Additional provisions. (a) Additional... Securities in Book-entry System. The interest of a debtor in a Security Entitlement may be reached by...

  19. 31 CFR 354.10 - Additional provisions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... SERVICE, DEPARTMENT OF THE TREASURY BUREAU OF THE PUBLIC DEBT REGULATIONS GOVERNING BOOK-ENTRY SECURITIES OF THE STUDENT LOAN MARKETING ASSOCIATION (SALLIE MAE) § 354.10 Additional provisions. (a) Additional... Securities in Book-entry System. The interest of a debtor in a Security Entitlement may be reached by...

  20. 31 CFR 354.10 - Additional provisions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... SERVICE, DEPARTMENT OF THE TREASURY BUREAU OF THE PUBLIC DEBT REGULATIONS GOVERNING BOOK-ENTRY SECURITIES OF THE STUDENT LOAN MARKETING ASSOCIATION (SALLIE MAE) § 354.10 Additional provisions. (a) Additional... Securities in Book-entry System. The interest of a debtor in a Security Entitlement may be reached by...