WorldWideScience

Sample records for ptr-ms emission ratios

  1. PTR-MS as a technique for investigating stress induced emission of biogenic VOCS

    International Nuclear Information System (INIS)

    Beauchamp, J.; Hansel, A.; Wisthaler, A.; Kleist, E.; Miebach, M.; Weller, U.; Wildt, J.

    2004-01-01

    Proton-transfer-reaction mass spectrometry (PTR-MS) was used in conjunction with two GC-MS systems to investigate stress induced emissions of volatile organic compounds (VOCs) from plants. Experiments were performed in the laboratory under well defined conditions and VOC emissions were induced by ozone exposure at variable concentrations and for different durations. Tobacco (Nicotiana tabaccum cv. Bel W3) plants were used as the investigated species. This investigation demonstrated the ability of PTR-MS to provide excellent high time-resolution on-line measurements of the relevant species. The combination of the PTR-MS instrument with the two GC-MS systems (which enabled accurate compound identification) allowed for detailed investigation of the dynamics of the plants' responses to ozone stress. VOCs measured included methanol, C6- alcohols and aldehydes, methyl salicylate and sesquiterpenes. Results indicate that the temporal stress response of plants depend on the amount of stress encountered by the plant. Measurement technique and experimental results will be presented. (author)

  2. Determination of material emission signatures by PTR-MS and their correlations with odor assessments by human subjects

    DEFF Research Database (Denmark)

    K H, Han; J S, Zhang; Wargocki, Pawel

    2010-01-01

    by human subjects. VOC emissions from each material were measured in a 50-l small-scale chamber. Chamber air was sampled by PTR-MS to determine emission signatures. Sorbent tube sampling and TD-GC/MS analysis were also performed to identify the major VOCs emitted and to compare the resulting data...... VOC odor indices was used to represent the emission level measured by PTR-MS.......The objectives of this study were to determine volatile organic compound (VOC) emission signatures of nine typical building materials by using proton transfer reaction-mass spectrometry (PTR-MS) and to explore the correlation between the PTR-MS measurements and the measurements of acceptability...

  3. The Tropical Forest and Fire Emissions Experiment: method evaluation of volatile organic compound emissions measured by PTR-MS, FTIR, and GC from tropical biomass burning

    Directory of Open Access Journals (Sweden)

    T. G. Karl

    2007-11-01

    Full Text Available Volatile Organic Compound (VOC emissions from fires in tropical forest fuels were quantified using Proton-Transfer-Reaction Mass Spectrometry (PTRMS, Fourier Transform Infrared Spectroscopy (FTIR and gas chromatography (GC coupled to PTRMS (GC-PTR-MS. We investigated VOC emissions from 19 controlled laboratory fires at the USFS (United States Forest Service Fire Sciences Laboratory and 16 fires during an intensive airborne field campaign during the peak of the burning season in Brazil in 2004. The VOC emissions were dominated by oxygenated VOCs (OVOC (OVOC/NMHC ~4:1, NMHC: non-methane hydrocarbons The specificity of the PTR-MS instrument, which measures the mass to charge ratio of VOCs ionized by H3O+ ions, was validated by gas chromatography and by intercomparing in-situ measurements with those obtained from an open path FTIR instrument. Emission ratios for methyl vinyl ketone, methacrolein, crotonaldehyde, acrylonitrile and pyrrole were measured in the field for the first time. Our measurements show a higher contribution of OVOCs than previously assumed for modeling purposes. Comparison of fresh (<15 min and aged (>1 h–1 d smoke suggests altered emission ratios due to gas phase chemistry for acetone but not for acetaldehyde and methanol. Emission ratios for numerous, important, reactive VOCs with respect to acetonitrile (a biomass burning tracer are presented.

  4. Effects of airflow on odorants' emissions in a model pig house — A laboratory study using Proton-Transfer-Reaction Mass Spectrometry (PTR-MS)

    International Nuclear Information System (INIS)

    Saha, Chayan Kumer; Feilberg, Anders; Zhang, Guoqiang; Adamsen, Anders Peter S.

    2011-01-01

    Identification of different factors that affect emissions of gasses, including volatile organic compounds (VOCs) is necessary to develop emission abatement technology. The objectives of this research were to quantify and study temporal variation of gas emissions from a model pig house under varying ventilation rates. The used model was a 1:12.5 scale of a section of a commercial finishing pig house. The VOC concentrations at inlet, outlet, and slurry pit of the model space were measured using Proton-Transfer-Reaction Mass Spectrometry (PTR-MS). PTR-MS can measure the temporal variations of odor compounds' emission from the slurry pit in real time. The emissions of H 2 S and 14 VOCs were lower compared to real pig buildings except for ammonia, which indicated possible other sources of those compounds than the slurry in the slurry pit. The ventilation rate affected significantly on ammonia and trimethylamine emission (p 2 S) emission was independent of the ventilation rate. VFAs' emission dependency on ventilation rate increased with the increase of carbon chain. Phenols, indoles and ketones showed the positive correlation with ventilation rate to some extent. Generally, compounds with high solubility (low Henry's constant) showed stronger correlation with ventilation rates than the compounds with high Henry's constant.

  5. Volatile organic compound (VOC) emissions characterization during the flow-back phase of a hydraulically refractured well in the Uintah Basin, Utah using mobile PTR-MS measurements

    Science.gov (United States)

    Geiger, F.; Warneke, C.; Brown, S. S.; De Gouw, J. A.; Dube, W. P.; Edwards, P.; Gilman, J.; Graus, M.; Helleis, F.; Kofler, J.; Lerner, B. M.; Orphal, J.; Petron, G.; Roberts, J. M.; Zahn, A.

    2014-12-01

    Ongoing improvements in advanced technologies for crude oil and natural gas extraction from unconventional reserves, such as directional drilling and hydraulic fracturing, have greatly increased the production of fossil fuels within recent years. The latest forecasts even estimate an enhancement of 56% in total natural gas production due to increased development of shale gas, tight gas and offshore natural gas resources from 2012 to 2040 with the largest contribution from shale formations [US EIA: Annual Energy Outlook 2014]. During the field intensive 'Energy and Environment - Uintah Basin Winter Ozone Study (UBWOS)', measurements of volatile organic compounds (VOCs) were made using proton-transfer-reactions mass spectrometry (PTR-MS) at the ground site Horse Pool and using a mobile laboratory in the Uintah Basin, Utah, which is a region well known for intense fossil fuel production. A reworked gas well in the Red Wash fields was sampled regularly within two weeks performing mobile laboratory measurements downwind of the well site. The well had been recently hydraulically refractured at that time and waste water was collected into an open flow-back pond. Very high mixing ratios of aromatic hydrocarbons (C6-C13) up to the ppm range were observed coming from condensate and flow-back reservoirs. The measurements are used to determine sources of specific VOC emissions originating from the different parts of the well site and mass spectra are used to classify the air composition in contrast to samples taken at the Horse Pool field site and crude oil samples from South Louisiana. Enhancement ratios and time series of measured peak values for aromatics showed no clear trend, which indicates changes in emissions with operations at the site.

  6. Tropospheric VOC measurements by PTR-MS

    International Nuclear Information System (INIS)

    Hansel, A.; Wisthaler, A.; Graus, M.; Grabmer, W.

    2002-01-01

    Full text: O 3 is formed photochemically from the photolysis of NO 2 , and because O 3 reacts rapidly with NO these reactions result in a photoequilibrium between NO, NO 2 with no net formation or loss of O 3 , However, in the presence of volatile organic compounds (VOCs), the degradation reactions of VOCs lead to the formation of intermediate peroxy radicals which react with NO, converting NO to NO 2 , which then photolyze to form O 3 . Thus, in order to understand quantitatively tropospheric ozone chemistry, it is necessary to know the VOC distribution within the troposphere as well as VOC fluxes from individual sources. Examples will be presented how the use of Proton Transfer Reaction Mass Spectrometry (PTR-MS) has enhanced our understanding of anthropogenic VOC emissions, biosphere-atmosphere exchange processes, and photochemical processing of both anthropogenic and biogenic VOCs in the troposphere. (author)

  7. A comparison of GC-FID and PTR-MS toluene measurements in ambient air under conditions of enhanced monoterpene loading

    Directory of Open Access Journals (Sweden)

    J. L. Ambrose

    2010-07-01

    Full Text Available Toluene was measured using both a gas chromatographic system (GC, with a flame ionization detector (FID, and a proton transfer reaction-mass spectrometer (PTR-MS at the AIRMAP atmospheric monitoring station Thompson Farm (THF in rural Durham, NH during the summer of 2004. Simultaneous measurements of monoterpenes, including α- and β-pinene, camphene, Δ 3-carene, and d-limonene, by GC-FID demonstrated large enhancements in monoterpene mixing ratios relative to toluene, with median and maximum enhancement ratios of ~2 and ~30, respectively. A detailed comparison between the GC-FID and PTR-MS toluene measurements was conducted to test the specificity of PTR-MS for atmospheric toluene measurements under conditions often dominated by biogenic emissions. We derived quantitative estimates of potential interferences in the PTR-MS toluene measurements related to sampling and analysis of monoterpenes, including fragmentation of the monoterpenes and some of their primary carbonyl oxidation products via reactions with H3O+, O2+ and NO+ in the PTR-MS drift tube. The PTR-MS and GC-FID toluene measurements were in good quantitative agreement and the two systems tracked one another well from the instrumental limits of detection to maximum mixing ratios of ~0.5 ppbv. A correlation plot of the PTR-MS versus GC-FID toluene measurements was described by the least squares regression equation y=(1.13± 0.02x−(0.008±0.003 ppbv, suggesting a small ~13% positive bias in the PTR-MS measurements. The bias corresponded with a ~0.055 ppbv difference at the highest measured toluene level. The two systems agreed quantitatively within the combined 1σ measurement precisions for 60% of the measurements. Discrepancies in the measured mixing ratios were not well correlated with enhancements in the monoterpenes. Better quantitative agreement between the two systems was obtained by

  8. Effects of air exchange, temperature and slurry management on odorant emissions from pig production units and slurry tanks studied by proton-transfer-reaction mass spectrometry (PTR-MS)

    Energy Technology Data Exchange (ETDEWEB)

    Feilberg, A.; Adamsen, A.P.S.; Liu, D.; Hansen, M.J.; Bildsoe, P. [Aarhus Univ., Tjele (Denmark). Dept. of Biosystems Engineering

    2010-07-01

    The factors affecting the variability of odorant emissions from intensive pig production facilities were examined using proton-transfer-reaction mass spectrometry (PTR-MS) to monitor emissions of odorants. Quantitative and time-resolved results for protonated ions representing hydrogen sulphide (H{sub 2}S), volatile organic sulphur compounds, organic amines, volatile carboxylic acids, carbonyls, phenols and indoles can be obtained. This study presented the results from PTRMS measurements of odorant emissions from finisher pig houses and finisher manure storage tanks. The measurements were performed at an experimental full-scale pig section with mechanical ventilation and at an experimental manure storage facility with controlled air exchange. Field measurements were taken during variable air exchange rates and temperatures, during finisher growth, and during emptying of the slurry pit. The results revealed a pronounced diurnal variation in emissions of odorants from the pig section with peaks in daytime coinciding with the highest ventilation rates and highest room temperatures. The highest emission rates were observed for H{sub 2}S and carboxylic acids. Based on odour threshold values, methanethiol and 4-methylphenol were estimated to contribute considerably to the odour nuisance. Discharging of the slurry pit led to reduced H{sub 2}S emissions, but peaks of H{sub 2}S were observed during manure handling.

  9. PTR-MS in environmental research: biogenic VOCs

    International Nuclear Information System (INIS)

    Beauchamp, J.; Grabmer, W.; Graus, M.; Wisthaler, A.; Hansel, A.

    2004-01-01

    Proton-transfer-reaction mass spectrometry (PTR-MS) is a chemical ionization mass spectrometry technique that allows for on-line measurements of volatile organic compounds (VOCs) at pptV levels. This well established analytical tool has been used in a broad variety of research, including the investigation of VOCs in various foods (e.g. for quality control or food degradation studies), as well as being used as a tool for non-invasive medical diagnostics (e.g. human breath analysis). In addition to these fields of study, PTR-MS has been widely used in environmental research, from trace gas analysis in the troposphere to VOC emissions from plants. Participation in two field campaigns (BEWA and ECHO - both part of the German AFO 2000 program) by the Institute of Ion Physics involved a variety of investigations for monitoring biogenic emissions. These included the technique of disjunct eddy covariance for flux measurements above a forest canopy, C-13 carbon labelling experiments to follow carbon use in a plant, and stress-induced VOC emission investigations to gain understanding of how plants react to stress (e.g. ozone exposure). A selection of results from these investigations will be discussed in this presentation. (author)

  10. Eddy covariance emission and deposition flux measurements using proton transfer reaction – time of flight – mass spectrometry (PTR-TOF-MS): comparison with PTR-MS measured vertical gradients and fluxes

    NARCIS (Netherlands)

    Park, J.H.; Goldstein, A.H.; Timkovsky, J|info:eu-repo/dai/nl/330541676; Fares, S.; Weber, R.; Karlik, J.; Holzinger, R.|info:eu-repo/dai/nl/337989338

    2013-01-01

    During summer 2010, a proton transfer reaction – time of flight – mass spectrometer (PTR-TOF-MS) and a quadrupole proton transfer reaction mass spectrometer (PTR-MS) were deployed simultaneously for one month in an orange orchard in the Central Valley of California to collect continuous data

  11. Investigation on the spoiling of meat using PTR-MS

    International Nuclear Information System (INIS)

    Mayr, D.; Maerk, T.D.; Margesin, R.; Schinner, F.

    2002-01-01

    The spoiling of meat was investigated. Beef (pork) were wrapped into different kinds of packages (air and vacuum) and stored at 4 o C for 10 (13) days. The emitted volatile organic compounds (VOCs) in the course of time were measured and a large increase in these emissions after a few days of storage was found. Also a large difference in the spoiling behavior between vacuum- and air- packed meat was observed. The measurements were performed using a proton-transfer-reaction-mass spectrometer(PTR-MS) system, it allows on-line monitoring of volatile organic compounds (VOCs) concentrations. Ethylacetate, methylpropionate, and propylformate were detected as typical spoiling compounds in pork samples. After 3.5 days the concentrations started to exponentially increase, but after 6 days remained more or less unchanged. This VOCs behaviour corresponds to a typical bacterial growth curve. Therefore, it was concluded that bacteria produce these components. In a second measurements set, the VOCs emitted by beef under aerobic (normal packed) and anaerobic (vacuum packed) conditions were compared. In the case of normal air-packed beef, the above mentioned spoiling compounds strongly increased with the time, while with the vacuum-packed beef a strong increase of ethanol was detected. This method as a replacement of the bacteriological examinations of meat spoilage is proposed. (nevyjel)

  12. Geographical origin classification of olive oils by PTR-MS

    NARCIS (Netherlands)

    Araghipour, N.; Colineau, J.; Koot, A.H.; Akkermans, W.; Rojas, J.M.M.; Beauchamp, J.; Wisthaler, A.; Märk, T.D.; Downey, G.; Guillou, C.; Mannina, L.; Ruth, van S.M.

    2008-01-01

    The volatile compositions of 192 olive oil samples from five different European countries were investigated by PTR-MS sample headspace analysis. The mass spectra of all samples showed many masses with high abundances, indicating the complex VOC composition of olive oil. Three different PLS-DA models

  13. Comparison of high sensitivity analytical methods (PTR-MS, MIMS, GC-O, SA) and application to food chemistry

    International Nuclear Information System (INIS)

    Boscaini, E.

    2002-10-01

    contributing to the odor profile not detected by FID were detected by PTR-MS. Principal component analysis (PCA) on both GC-0 and PTR-MS data well separated the three cheese samples and showed specific compounds related to each sample. The combination of membrane introduction mass spectrometry (MIMS) and proton transfer reaction mass spectrometry (PTR-MS) is explored in the last session of this thesis. The PTR-MS is used to measure properties of a well-characterized membrane material, poly-dimethylsiloxane (PDMS). It is found that the ability of the PTR-MS to measure absolute concentrations in real-time makes it an ideal tool for the characterization of membrane properties and the interaction of the membrane with multiple organic species. Values for the diffusion coefficients of several molecules are measured and found to be in agreement with literature values. Time modulation of the analyte across the membrane is explored as a method of resolving isobaric interferences for different chemical species. This is demonstrated for acetone and propanal. Finally, the benefit of combining MIMS with PTR-MS is demonstrated by the direct analysis of organic species in the headspace of a hot water solution where the high humidity would not allow analysis using the PTR-MS alone. The effect of membrane thickness and temperature on rise (or response) time and on solubility (or on partition coefficient) can be easily quantified with the use of PTR-MS. Increasing the membrane thickness the rise time increases, the values obtained for the rise time ratios are reasonably close to theoretical values. Temperature increase shows large effects on rise time and solubility. Compounds having stronger interactions with the polymer, i.e. methanol and acetone, are more effected by temperature changing than non-polar compounds, i.e. benzene and toluene. The presence of methyl groups also seems to influence physical properties as response time and solubility. The overall effect of temperature increase is to

  14. Ambient measurements of aromatic and oxidized VOCs by PTR-MS and GC-MS: intercomparison between four instruments in a boreal forest in Finland

    Science.gov (United States)

    Kajos, M. K.; Rantala, P.; Hill, M.; Hellén, H.; Aalto, J.; Patokoski, J.; Taipale, R.; Hoerger, C. C.; Reimann, S.; Ruuskanen, T. M.; Rinne, J.; Petäjä, T.

    2015-10-01

    Proton transfer reaction mass spectrometry (PTR-MS) and gas chromatography mass spectrometry GC-MS) are commonly used methods for automated in situ measurements of various volatile organic compounds (VOCs) in the atmosphere. In order to investigate the reliability of such measurements, we operated four automated analyzers using their normal field measurement protocol side by side at a boreal forest site. We measured methanol, acetaldehyde, acetone, benzene and toluene by two PTR-MS and two GC-MS instruments. The measurements were conducted in southern Finland between 13 April and 14 May 2012. This paper presents correlations and biases between the concentrations measured using the four instruments. A very good correlation was found for benzene and acetone measurements between all instruments (the mean R value was 0.88 for both compounds), while for acetaldehyde and toluene the correlation was weaker (with a mean R value of 0.50 and 0.62, respectively). For some compounds, notably for methanol, there were considerable systematic differences in the mixing ratios measured by the different instruments, despite the very good correlation between the instruments (mean R = 0.90). The systematic difference manifests as a difference in the linear regression slope between measurements conducted between instruments, rather than as an offset. This mismatch indicates that the systematic uncertainty in the sensitivity of a given instrument can lead to an uncertainty of 50-100 % in the methanol emissions measured by commonly used methods.

  15. Quality control of meat using proton-transfer-reaction-mass-spectrometry (PTR-MS)

    International Nuclear Information System (INIS)

    Mayr, D.; Hartungen, E.; Maerk, T.D.; Margesin, R.; Schinner, F.

    2002-01-01

    Full text: Numerous food scandals which happened during the last few years make food safety controls more and more important. The method currently used for determining the status of meat, with respect to spoilage, is analysis of the counts of total viable bacteria and/or specific spoilage bacteria. An obvious drawback of this bacteriological method is the long incubation period of 1-3 days that is required for colony formation. Therefore we develop a novel method for meat quality control using PTR-MS which does not have this drawback. We measured the emitted volatile organic compounds (VOCs) of meat (beef and pork) using PTR-MS as a function of storage time. At the same time a bacteriological examination of these meat samples was carried out. We found strong correlations (about 99 %) between some VOCs and bacteriological contamination. This is a first step to replace the time-consuming bacteriological method by fast headspace air measurements to facilitate the investigation of a huge number of pieces of meat in very short time and to determine the maximum storage time and storage temperature from the emissions. We will also use this method to investigate the growth of various bacteria, the changes in the microbial composition and the influence of various environmental conditions such as temperature, pH, chemical and microbial preservation techniques. (author)

  16. Comparison of Aromatic Hydrocarbon Measurements made by PTR-MS, DOAS and GC-FID during the MCMA 2003 Field Experiment

    International Nuclear Information System (INIS)

    Jobson, Bertram T.; Volkamer, Rainer M.; Velasco, E.; Allwine, Gene; Westberg, Halvor H.; Lamb, Brian K.; Alexander, M.L.; Berkowitz, Carl M.; Molina, Luisa T.

    2010-01-01

    A comparison of aromatic hydrocarbon measurements is reported for the CENICA upersite in the district of Iztapalapa during the Mexico City Metropolitan Area field experiment in April 2003 (MCMA 2003). Data from three different measurement methods were compared: a Proton Transfer Reaction Mass Spectrometer (PTR-MS), long path measurements using a UV Differential Optical Absorption Spectrometer (DOAS), and Gas Chromatography-Flame Ionization analysis (GC-FID) of canister samples. The principle focus was on the comparison between PTR-MS and DOAS data. Lab tests established that the PTR-MS and DOAS calibrations were consistent for a suite of aromatic compounds including benzene, toluene, p-xylene, ethylbenzene, 1,2,4-trimethylbenzene, phenol and styrene. The point sampling measurements by the PTR-MS and GC-FID showed good correlations (r=0.6), and were in reasonable agreement for toluene, C 2 -alkylbenzenes and C3-alkylbenzenes. The PTR-MS benzene data were consistently high, indicating interference from ethylbenzene fragmentation for the 145 Td drift field intensity used in the experiment. Correlations between the open-path data measured at 16-m height over a 860-m path length (retroreflector in 430m distance), and the point measurements collected at 37-m sampling height were best for benzene (r=0.61), and reasonably good for toluene, C2-alkylbenzenes, naphthalene, styrene, cresols and phenol (r>0.5). There was good agreement between DOAS and PTR-MS measurements of benzene after correction for the PTR-MS ethylbenzene interference. Mixing ratios easured by DOAS were on average a factor of 1.7 times greater than the PTR-MS data for toluene, C2-alkylbenzenes, naphthalene and styrene. The level of agreement for the toluene data displayed a modest dependence on wind direction, establishing that spatial gradients - horizontal, vertical, or both - in toluene mixing ratios were significant, and up to a factor of 2 despite the fact that all measurements were conducted above

  17. Formaldehyde measurements by Proton transfer reaction – Mass Spectrometry (PTR-MS: correction for humidity effects

    Directory of Open Access Journals (Sweden)

    A. Vlasenko

    2010-08-01

    Full Text Available Formaldehyde measurements can provide useful information about photochemical activity in ambient air, given that HCHO is formed via numerous oxidation processes. Proton transfer reaction mass spectrometry (PTR-MS is an online technique that allows measurement of VOCs at the sub-ppbv level with good time resolution. PTR-MS quantification of HCHO is hampered by the humidity dependence of the instrument sensitivity, with higher humidity leading to loss of PTR-MS signal. In this study we present an analytical, first principles approach to correct the PTR-MS HCHO signal according to the concentration of water vapor in sampled air. The results of the correction are validated by comparison of the PTR-MS results to those from a Hantzsch fluorescence monitor which does not have the same humidity dependence. Results are presented for an intercomparison made during a field campaign in rural Ontario at Environment Canada's Centre for Atmospheric Research Experiments.

  18. Measuring OVOCs and VOCs by PTR-MS in an urban roadside microenvironment of Hong Kong: relative humidity and temperature dependence, and field intercomparisons

    Science.gov (United States)

    Cui, Long; Zhang, Zhou; Huang, Yu; Lee, Shun Cheng; Blake, Donald Ray; Ho, Kin Fai; Wang, Bei; Gao, Yuan; Wang, Xin Ming; Kwok Keung Louie, Peter

    2016-12-01

    Volatile organic compound (VOC) control is an important issue of air quality management in Hong Kong because ozone formation is generally VOC limited. Several oxygenated volatile organic compound (OVOC) and VOC measurement techniques - namely, (1) offline 2,4-dinitrophenylhydrazine (DNPH) cartridge sampling followed by high-performance liquid chromatography (HPLC) analysis; (2) online gas chromatography (GC) with flame ionization detection (FID); and (3) offline canister sampling followed by GC with mass spectrometer detection (MSD), FID, and electron capture detection (ECD) - were applied during this study. For the first time, the proton transfer reaction-mass spectrometry (PTR-MS) technique was also introduced to measured OVOCs and VOCs in an urban roadside area of Hong Kong. The integrated effect of ambient relative humidity (RH) and temperature (T) on formaldehyde measurements by PTR-MS was explored in this study. A Poly 2-D regression was found to be the best nonlinear surface simulation (r = 0.97) of the experimental reaction rate coefficient ratio, ambient RH, and T for formaldehyde measurement. This correction method was found to be better than correcting formaldehyde concentrations directly via the absolute humidity of inlet sample, based on a 2-year field sampling campaign at Mong Kok (MK) in Hong Kong. For OVOC species, formaldehyde, acetaldehyde, acetone, and MEK showed good agreements between PTR-MS and DNPH-HPLC with slopes of 1.00, 1.10, 0.76, and 0.88, respectively, and correlation coefficients of 0.79, 0.75, 0.60, and 0.93, respectively. Overall, fair agreements were found between PTR-MS and online GC-FID for benzene (slope = 1.23, r = 0.95), toluene (slope = 1.01, r = 0.96) and C2-benzenes (slope = 1.02, r = 0.96) after correcting benzene and C2-benzenes levels which could be affected by fragments formed from ethylbenzene. For the intercomparisons between PTR-MS and offline canister measurements by GC-MSD/FID/ECD, benzene showed good agreement

  19. Airborne measurements of reactive organic trace gases in the atmosphere - with a focus on PTR-MS measurements onboard NASA's flying laboratories

    Science.gov (United States)

    Wisthaler, Armin; Mikoviny, Tomas; Müller, Markus; Schiller, Sven Arne; Feil, Stefan; Hanel, Gernot; Jordan, Alfons; Mutschlechner, Paul; Crawford, James H.; Singh, Hanwant B.; Millet, Dylan

    2017-04-01

    Reactive organic gases (ROGs) play an important role in atmospheric chemistry as they affect the rates of ozone production, particle formation and growth, and oxidant consumption. Measurements of ROGs are analytically challenging because of their large variety and low concentrations in the Earth's atmosphere, and because they are easily affected by measurement artefacts. On aircraft, ROGs are typically measured by canister sampling followed by off-line analysis in the laboratory, fast online gas chromatography or online chemical ionization mass spectrometry. In this work, we will briefly sum up the state-of-the-art in this field before focusing on proton-transfer-reaction mass spectrometry (PTR-MS) and its deployment onboard NASA's airborne science laboratories. We will show how airborne PTR-MS was successfully used in NASA missions for characterizing emissions of ROGs from point sources, for following the photochemical evolution of ROGs in a biomass burning plume, for determining biosphere-atmosphere fluxes of selected ROGs and for validating satellite data. We will also present the airborne PTR-MS instrument in its most recent evolution which includes a radiofrequency ion funnel and ion guide combined with a compact time-of-flight mass spectrometer and discuss its superior performance characteristics. The development of the airborne PTR-MS instrument was supported by the Austrian Federal Ministry for Transport, Innovation and Technology (bmvit) through the Austrian Space Applications Programme (ASAP) of the Austrian Research Promotion Agency (FFG) (grants #833451, #847967). This work was also partly supported by NASA under grant #NNX14AP89G.

  20. Comparison of aromatic hydrocarbon measurements made by PTR-MS, DOAS and GC-FID during the MCMA 2003 Field Experiment

    Directory of Open Access Journals (Sweden)

    B. T. Jobson

    2010-02-01

    Full Text Available A comparison of aromatic hydrocarbon measurements is reported for the CENICA supersite in the district of Iztapalapa during the Mexico City Metropolitan Area field experiment in April 2003 (MCMA 2003. Data from three different measurement methods were compared: a Proton Transfer Reaction Mass Spectrometer (PTR-MS, long path measurements using a UV Differential Optical Absorption Spectrometer (DOAS, and Gas Chromatography-Flame Ionization analysis (GC-FID of canister samples. The principle focus was on the comparison between PTR-MS and DOAS data. Lab tests established that the PTR-MS and DOAS calibrations were consistent for a suite of aromatic compounds including benzene, toluene, p-xylene, ethylbenzene, 1,2,4-trimethylbenzene, phenol and styrene. The point sampling measurements by the PTR-MS and GC-FID showed good correlations (r=0.6, and were in reasonable agreement for toluene, C2-alkylbenzenes and C3-alkylbenzenes. The PTR-MS benzene data were consistently high, indicating interference from ethylbenzene fragmentation for the 145 Td drift field intensity used in the experiment. Correlations between the open-path data measured at 16-m height over a 860-m path length (retroreflector in 430 m distance, and the point measurements collected at 37-m sampling height were best for benzene (r=0.61, and reasonably good for toluene, C2-alkylbenzenes, naphthalene, styrene, cresols and phenol (r>0.5. There was good agreement between DOAS and PTR-MS measurements of benzene after correction for the PTR-MS ethylbenzene interference. Mixing ratios measured by DOAS were on average a factor of 1.7 times greater than the PTR-MS data for toluene, C2-alkylbenzenes, naphthalene and styrene. The level of agreement for the toluene data displayed a modest dependence on wind direction, establishing that spatial gradients – horizontal, vertical, or both – in toluene mixing ratios were significant, and

  1. Discrimination of Polish unifloral honeys using overall PTR-MS and HPLC fingerprints combined with chemometrics

    NARCIS (Netherlands)

    Kus, P.M.; Ruth, van S.M.

    2015-01-01

    A total of 62 honey samples of six floral origins (rapeseed, lime, heather, cornflower, buckwheat and black locust) were analysed by means of proton transfer reaction mass spectrometry (PTR-MS) and HPLC-DAD. The data were evaluated by principal component analysis and k-nearest neighbours

  2. Applications of PTR-MS in food flavour research: recent progress and prospects

    International Nuclear Information System (INIS)

    Yeretzian, C.; Pollien, P.; Jordan, A.; Graus, M.; Lindinger, W.

    2002-01-01

    Food products all along the food chain from raw material to final products continuously emit volatile organic compounds (VOs), which are related to important properties of the product itself such as flavor, age, or safety among others. Several analytical techniques for sampling and analysing the head space (HS) of food has been developed, however the proton-transfer-reaction mass spectrometry (PTR-MS) has the particularity to be able to work on real time-basis. By applying PTR-MS two qualitatively distinct types of information were obtained: HS profiles can be averaged over a given time window to yield concentration vs. mass spectra (static data). Such spectra can be used to asses authenticity, monitor deviation in production from a reference or classify product. Alternatively, temporal changes can be analysed via time-intensity plots (dynamic data). As example soluble coffee data is given. (nevyjel)

  3. Ground-based PTR-MS measurements of reactive organic compounds during the MINOS campaign in Crete, July–August 2001

    Directory of Open Access Journals (Sweden)

    G. Salisbury

    2003-01-01

    Full Text Available This study presents measurements of acetonitrile, benzene, toluene, methanol and acetone made using the proton-transfer-reaction mass spectrometry (PTR-MS technique at the Finokalia ground station in Crete during the Mediterranean INtensive Oxidant Study (MINOS in July-August 2001. Three periods during the campaign with broadly consistent back trajectories are examined in detail. In the first, air was advected from Eastern Europe without significant biomass burning influence (mean acetonitrile mixing ratio 154 pmol/mol. In the second period, the sampled air masses originated in Western Europe, and were advected approximately east-south-east, before turning south-west over the Black Sea and north-western Turkey. The third well-defined period included air masses advected from Eastern Europe passing east and south of/over the Sea of Azov, and showed significant influence by biomass burning (mean acetonitrile mixing ratio 436 pmol/mol, confirmed by satellite pictures. The mean toluene:benzene ratios observed in the three campaign periods described were 0.35, 0.37 and 0.22, respectively; the use of this quantity to determine air mass age is discussed. Methanol and acetone were generally well-correlated both with each other and with carbon monoxide throughout the campaign. Comparison of the acetone and methanol measurements with the MATCH-MPIC model showed that the model underestimated both species by a factor of 4, on average. The correlations between acetone, methanol and CO implied that the relatively high levels of methanol observed during MINOS were largely due to direct biogenic emissions, and also that biogenic sources of acetone were highly significant during MINOS (~35%. This in turn suggests that the model deficit in both species may be due, at least in part, to missing biogenic emissions.

  4. PTR-MS analysis of reference and plant-emitted volatile organic compounds

    Science.gov (United States)

    Maleknia, Simin D.; Bell, Tina L.; Adams, Mark A.

    2007-05-01

    Proton transfer reaction-mass spectrometry (PTR-MS) was applied to the analysis of a series of volatile organic compounds (VOCs) that emit from various plants. These include a group of alcohols (methanol, ethanol and butanol), carbonyl-containing compounds (acetic acid, acetone and benzaldehyde), isoprene, acetonitrile, tetrahydrofuran (THF), pyrazine, toluene and xylene and a series of terpenes (p-cymene, camphene, 2-carene, limonene, [beta]-myrcene, [alpha]-pinene, [beta]-pinene, [gamma]-tepinene and terpinolene) and oxygen-containing terpenes (1,8-cineole and linalool). These mass spectral data were compared to an electron ionization (EI) database identifying that not all PTR-MS fragments were common to EI. PTR-MS studies of these reference compounds were utilized to identify VOCs emitted from Eucalyptus grandis leaf at a temperature range of 30-100 °C. In addition to protonated molecules (M + H)+, abundant proton-bound dimers or trimers were detected for alcohols, acetone, acetonitrile and THF. Abundant fragment ions attributed to the loss of water from these proton-bound clusters were also observed. The stability of butyl (C4H9+ m/z 57) and acetyl (CH3CO+ m/z 43) fragment ions directed the proton-transfer reactions of butanol and acetic acid. Abundant (M + H)+ ions were detected for pyrazine, THF, toluene and xylene, as well as for all terpenes except those containing oxygen. For linalool and 1,8-cineole, the loss of water generated an abundant fragment ion at m/z 137. PTR-MS fragmentation patterns for terpenes were proposed for m/z 81 (C6H9+), 93 (C7H9+), 95 (C7H11+), 107 (C8H11+), 109 (C8H13+), 119 (C9H11+), 121 (C9H13+) and 137 (loss of water for oxygen-containing terpenes; C10H17+). The relative abundances of (M + H)+ and fragments for all terpenes (except linalool) were dependent on the drift tube voltage and the optimum voltage for detection of molecular ions was different for various terpenes.

  5. Analysis of trace gases at ppb levels by proton transfer reaction mass spectrometry (PTR-MS)

    International Nuclear Information System (INIS)

    Lindinger, W.; Hansel, A.

    1996-01-01

    A proton transfer reaction mass spectrometry (PTR-MS) system has been developed which allows for on-line measurements of trace gas components with concentrations as low as 1 ppb. The method is based on reactions of H 3 O + ions, which perform non-dissociative proton transfer to most of the common organic trace constituents but do not react with any of the components present in clean air. Examples of medical information obtained by means of breath analysis, of environmental trace analysis, and examples in the field of food chemistry demonstrate the wide applicability of the method. (Authors)

  6. Direct, rapid quantitative analyses of BVOCs using SIFT-MS and PTR-MS obviating sample collection

    Czech Academy of Sciences Publication Activity Database

    Smith, D.; Španěl, Patrik

    2011-01-01

    Roč. 30, č. 7 (2011), s. 945-959 ISSN 0165-9936 Institutional research plan: CEZ:AV0Z40400503 Keywords : SIFT-MS * PTR-MS * Absolute quantification Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 6.273, year: 2011

  7. Proton-transfer reaction mass spectrometry (PTR-MS) for the authentication of regionally unique South African lamb

    NARCIS (Netherlands)

    Erasmus, Sara W.; Muller, Magdalena; Alewijn, Martin; Koot, Alex H.; Ruth, van Saskia M.; Hoffman, Louwrens C.

    2017-01-01

    The volatile fingerprints of South African lamb meat and fat were measured by proton-transfer mass spectrometry (PTR-MS) to evaluate it as an authentication tool. Meat and fat of the Longissimus lumborum (LL) of lambs from six different regions were assessed. Analysis showed that the volatile

  8. VOC identification and inter-comparison from laboratory biomass burning using PTR-MS and PIT-MS

    Science.gov (United States)

    C. Warneke; J. M. Roberts; P. Veres; J. Gilman; W. C. Kuster; I. Burling; R. Yokelson; J. A. de Gouw

    2011-01-01

    Volatile organic compounds (VOCs) emitted from fires of biomass commonly found in the southeast and southwest U.S. were investigated with PTR-MS and PIT-MS, which are capable of fast measurements of a large number of VOCs. Both instruments were calibrated with gas standards and mass dependent calibration curves are determined. The sensitivity of the PIT-MS linearly...

  9. Compounds enhanced in a mass spectrometric profile of smokers' exhaled breath versus non-smokers as determined in a pilot study using PTR-MS.

    Science.gov (United States)

    Kushch, Ievgeniia; Schwarz, Konrad; Schwentner, Lukas; Baumann, Bettina; Dzien, Alexander; Schmid, Alex; Unterkofler, Karl; Gastl, Günter; Spaněl, Patrik; Smith, David; Amann, Anton

    2008-06-01

    A pilot study has been carried out to define typical characteristics of the trace gas compounds in exhaled breath of non-smokers and smokers to assist interpretation of breath analysis data from patients who smoke with respiratory diseases and lung cancer. Exhaled breath was analyzed using proton transfer reaction-mass spectrometry (PTR-MS) for 370 volunteers (81 smokers, 210 non-smokers, 79 ex-smokers). Volatile organic compounds corresponding to product ions at seven mass-to-charge ratios (m/z 28, 42, 69, 79, 93, 97, 123) in the PTR-MS spectra differentiated between smokers and non-smokers. The Youden index (= maximum of sensitivity + specificity - 1, YI) as a measure for differentiation between smokers and non-smokers was YI = 0.43 for ions at the m/z values 28 (tentatively identified as HCN), YI = 0.75 for m/z = 42 (tentatively identified as acetonitrile) and YI = 0.53 for m/z = 79 (tentatively identified as benzene). No statistically significant difference between smokers and non-smokers was observed for the product ions at m/z = 31 and 33 (compounds tentatively identified as formaldehyde and methanol). When interpreting the exhaled breath of lung cancer or COPD patients, who often smoke, compounds appearing at the above-mentioned seven mass-to-charge ratios should be considered with appropriate care to avoid misdiagnosis. Validation studies in larger numbers of patients with more precise delineation of their smoking behavior and using additional analytical techniques such as GC/MS and SIFT-MS should be carried out.

  10. Explosives and chemical warfare agents - detection and analysis with PTR-MS

    Energy Technology Data Exchange (ETDEWEB)

    Sulzer, Philipp; Juerschik, Simone; Jaksch, Stefan; Jordan, Alfons; Hanel, Gernot; Hartungen, Eugen; Seehauser, Hans; Maerk, Lukas; Haidacher, Stefan; Schottkowsky, Ralf [IONICON Analytik GmbH, Innsbruck (Austria); Petersson, Fredrik [Institut fuer Ionenphysik und Angewandte Physik, Leopold-Franzens Universitaet Innsbruck (Austria); Maerk, Tilmann [IONICON Analytik GmbH, Innsbruck (Austria); Institut fuer Ionenphysik und Angewandte Physik, Leopold-Franzens Universitaet Innsbruck (Austria)

    2010-07-01

    We utilized a recently developed high sensitivity PTR-MS instrument equipped with a high resolution time-of-flight mass analyzer for detailed investigations on explosives and chemical warfare agents (CWAs). We show that with this so called PTR-TOF 8000 it is possible to identify solid explosives (RDX, TNT, HMX, PETN and Semtex A) by analyzing the headspace above small quantities of samples at room temperature and from trace quantities not visible to the naked eye placed on surfaces. As the mentioned solid explosives possess very low vapor pressures, the main challenge for detecting them in the gas phase is to provide an instrument with a sufficient sensitivity. CWAs on the other side have very high vapor pressures but are difficult to identify unambiguously as their nominal molecular masses are usually comparably small and therefore hard to distinguish from harmless everyday-compounds (e.g. mustard gas: 159 g/mol). In the present work we demonstrate that we can detect a broad range of dangerous substances, ranging from the CWA mustard gas to the explosive HMX.

  11. Long-term study of VOCs measured with PTR-MS at a rural site in New Hampshire with urban influences

    Directory of Open Access Journals (Sweden)

    R. Talbot

    2009-07-01

    Full Text Available A long-term, high time-resolution volatile organic compound (VOC data set from a ground site that experiences urban, rural, and marine influences in the Northeastern United States is presented. A proton-transfer-reaction mass spectrometer (PTR-MS was used to quantify 15 VOCs: a marine tracer dimethyl sulfide (DMS, a biomass burning tracer acetonitrile, biogenic compounds (monoterpenes, isoprene, oxygenated VOCs (OVOCs: methyl vinyl ketone (MVK plus methacrolein (MACR, methanol, acetone, methyl ethyl ketone (MEK, acetaldehyde, and acetic acid, and aromatic compounds (benzene, toluene, C8 and C9 aromatics. Time series, overall and seasonal medians, with 10th and 90th percentiles, seasonal mean diurnal profiles, and inter-annual comparisons of mean summer and winter diurnal profiles are shown. Methanol and acetone exhibit the highest overall median mixing ratios 1.44 and 1.02 ppbv, respectively. Comparing the mean diurnal profiles of less well understood compounds (e.g., MEK with better known compounds (e.g., isoprene, monoterpenes, and MVK + MACR that undergo various controls on their atmospheric mixing ratios provides insight into possible sources of the lesser known compounds. The constant diurnal value of ~0.7 for the toluene:benzene ratio in winter, may possibly indicate the influence of wood-based heating systems in this region. Methanol exhibits an initial early morning release in summer unlike any other OVOC (or isoprene and a dramatic late afternoon mixing ratio increase in spring. Although several of the OVOCs appear to have biogenic sources, differences in features observed between isoprene, methanol, acetone, acetaldehyde, and MEK suggest they are produced or emitted in unique ways.

  12. Volatile organic compound emissions from the oil and natural gas industry in the Uinta Basin, Utah: point sources compared to ambient air composition

    OpenAIRE

    C. Warneke; F. Geiger; P. M. Edwards; W. Dube; G. Pétron; J. Kofler; A. Zahn; S. S. Brown; M. Graus; J. Gilman; B. Lerner; J. Peischl; T. B. Ryerson; J. A. de Gouw; J. M. Roberts

    2014-01-01

    The emissions of volatile organic compounds (VOCs) associated with oil and natural gas production in the Uinta Basin, Utah were measured at a ground site in Horse Pool and from a NOAA mobile laboratory with PTR-MS instruments. The VOC compositions in the vicinity of individual gas and oil wells and other point sources such as evaporation ponds, compressor stations and injection wells are compared to the measurements at Horse Pool. High mixing ratios of aroma...

  13. On-line detection of illicit substances in liquid phase with proton-transfer-reaction mass spectrometry (PTR-MS)

    Energy Technology Data Exchange (ETDEWEB)

    Juerschik, Simone; Agarwal, Bishu; Petersson, Fredrik [Institut fuer Ionenphysik und Angewandte Physik, Universitaet Innsbruck, Technikerstr. 25, 6020 Innsbruck (Austria); Sulzer, Philipp; Haidacher, Stefan; Jordan, Alfons; Schottkowsky, Ralf; Hartungen, Eugen; Hanel, Gernot; Seehauser, Hans; Maerk, Lukas [IONICON Analytik GmbH, Eduard-Bodem-Gasse 3, 6020 Innsbruck (Austria); Maerk, Tilmann D. [Institut fuer Ionenphysik und Angewandte Physik, Universitaet Innsbruck, Technikerstr. 25, 6020 Innsbruck (Austria); IONICON Analytik GmbH, Eduard-Bodem-Gasse 3, 6020 Innsbruck (Austria)

    2011-07-01

    The direct aqueous injection (DAI) technique was recently utilized for the detection of illicit substances in liquid phase. DAI turns out to be an ideal solution for direct analysis of liquid samples, since we can make good use of the outstanding advantages, such as real-time analysis, no sample preparation, low detection limits and short response time. Differences in TNT concentration in the water could be seen dependent on time and original size of the pieces and we could demonstrate a linear correlation between the concentration in liquid and the PTR-MS signal. Furthermore, we were also able to demonstrate that this method is capable of detecting minute traces of ''rape drugs'', i.e. {gamma}-butyrolactone and 1,4-butanediol, in liquids. This new method achieving sensitivities in the around 100 pptw range appears therefore well suited for the fight against drug crime and terrorism and for the evaluation of contamination of ammunition dumping sites.

  14. Proton-transfer reaction mass spectrometry (PTR-MS) for the authentication of regionally unique South African lamb.

    Science.gov (United States)

    Erasmus, Sara W; Muller, Magdalena; Alewijn, Martin; Koot, Alex H; van Ruth, Saskia M; Hoffman, Louwrens C

    2017-10-15

    The volatile fingerprints of South African lamb meat and fat were measured by proton-transfer mass spectrometry (PTR-MS) to evaluate it as an authentication tool. Meat and fat of the Longissimus lumborum (LL) of lambs from six different regions were assessed. Analysis showed that the volatile fingerprints were affected by the origin of the meat. The classification of the origin of the lamb was achieved by examining the calculated and recorded fingerprints in combination with chemometrics. Four different partial least squares discriminant analysis (PLS-DA) models were fitted to the data to classify lamb meat and fat samples into "region of origin" (six different regions) and "origin" (Karoo vs. Non-Karoo). The estimation models classified samples 100% correctly. Validation of the first two models gave 42% (fat) and 58% (meat) correct classification of region, while the second two models performed better with 92% (fat) and 83% (meat) correct classification of origin. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Real-time profiling of organic trace gases in the planetary boundary layer by PTR-MS using a tethered balloon

    Directory of Open Access Journals (Sweden)

    R. Schnitzhofer

    2009-12-01

    Full Text Available A method for real-time profiling of volatile organic compounds (VOCs was developed combining the advantages of a tethered balloon as a research platform and of proton transfer reaction mass spectrometry (PTR-MS as an analytical technique for fast and highly sensitive VOC measurements. A 200 m Teflon tube was used to draw sampling air from a tethered aerodynamic balloon to the PTR-MS instrument. Positive and negative artefacts (i.e. formation and loss of VOCs in the tube were characterised in the laboratory and in the field by a set of 11 atmospherically relevant VOCs including both pure and oxygenated hydrocarbons. The only two compounds that increased or decreased when sampled through the tube were acetone (+7% and xylene (-6%. The method was successfully deployed during a winter field campaign to determine the small scale spatial and temporal patterns of air pollutants under winter inversion conditions.

  16. Investigation of Volatiles Emitted from Freshly Cut Onions (Allium cepa L. by Real Time Proton-Transfer Reaction-Mass Spectrometry (PTR-MS

    Directory of Open Access Journals (Sweden)

    Mette Marie Løkke

    2012-11-01

    Full Text Available Volatile organic compounds (VOCs in cut onions (Allium cepa L. were continuously measured by PTR-MS during the first 120 min after cutting. The headspace composition changed rapidly due to the very reactive volatile sulfurous compounds emitted from onion tissue after cell disruption. Mass spectral signals corresponding to propanethial S-oxide (the lachrymatory factor and breakdown products of this compound dominated 0–10 min after cutting. Subsequently, propanethiol and dipropyl disulfide predominantly appeared, together with traces of thiosulfinates. The concentrations of these compounds reached a maximum at 60 min after cutting. Propanethiol was present in highest concentrations and had an odor activity value 20 times higher than dipropyl disulfide. Thus, propanethiol is suggested to be the main source of the characteristic onion odor. Monitoring the rapid changes of VOCs in the headspace of cut onion necessitates a high time resolution, and PTR-MS is demonstrated to be a very suitable method for monitoring the headspace of freshly cut onions directly after cutting without extraction or pre-concentration.

  17. Measurements of volatile organic compounds at a suburban ground site (T1 in Mexico City during the MILAGRO 2006 campaign: measurement comparison, emission ratios, and source attribution

    Directory of Open Access Journals (Sweden)

    D. M. Bon

    2011-03-01

    Full Text Available Volatile organic compound (VOC mixing ratios were measured with two different instruments at the T1 ground site in Mexico City during the Megacity Initiative: Local and Global Research Observations (MILAGRO campaign in March of 2006. A gas chromatograph with flame ionization detector (GC-FID quantified 18 light alkanes, alkenes and acetylene while a proton-transfer-reaction ion-trap mass spectrometer (PIT-MS quantified 12 VOC species including oxygenated VOCs (OVOCs and aromatics. A GC separation system was used in conjunction with the PIT-MS (GC-PIT-MS to evaluate PIT-MS measurements and to aid in the identification of unknown VOCs. The VOC measurements are also compared to simultaneous canister samples and to two independent proton-transfer-reaction mass spectrometers (PTR-MS deployed on a mobile and an airborne platform during MILAGRO. VOC diurnal cycles demonstrate the large influence of vehicle traffic and liquid propane gas (LPG emissions during the night and photochemical processing during the afternoon. Emission ratios for VOCs and OVOCs relative to CO are derived from early-morning measurements. Average emission ratios for non-oxygenated species relative to CO are on average a factor of ~2 higher than measured for US cities. Emission ratios for OVOCs are estimated and compared to literature values the northeastern US and to tunnel studies in California. Positive matrix factorization analysis (PMF is used to provide insight into VOC sources and processing. Three PMF factors were distinguished by the analysis including the emissions from vehicles, the use of liquid propane gas and the production of secondary VOCs + long-lived species. Emission ratios to CO calculated from the results of PMF analysis are compared to emission ratios calculated directly from measurements. The total PIT-MS signal is summed to estimate the fraction of identified versus unidentified VOC species.

  18. Measurements of volatile organic compounds at a suburban ground site (T1) in Mexico City during the MILAGRO 2006 campaign: Measurement comparison, emission ratios, and source attribution

    Energy Technology Data Exchange (ETDEWEB)

    Bon, D.M.; Springston, S.; M.Ulbrich, I.; de Gouw, J. A.; Warneke, C.; Kuster, W. C.; Alexander, M. L.; Baker, A.; Beyersdorf, A. J.; Blake, D.; Fall, R.; Jimenez, J. L., Herndon, S. C.; Huey, L. G.; Knighton, W. B.; Ortega, J.; Vargas, O.

    2011-03-16

    Volatile organic compound (VOC) mixing ratios were measured with two different instruments at the T1 ground site in Mexico City during the Megacity Initiative: Local and Global Research Observations (MILAGRO) campaign in March of 2006. A gas chromatograph with flame ionization detector (GC-FID) quantified 18 light alkanes, alkenes and acetylene while a proton-transfer-reaction ion-trap mass spectrometer (PIT-MS) quantified 12 VOC species including oxygenated VOCs (OVOCs) and aromatics. A GC separation system was used in conjunction with the PIT-MS (GC-PIT-MS) to evaluate PIT-MS measurements and to aid in the identification of unknown VOCs. The VOC measurements are also compared to simultaneous canister samples and to two independent proton-transfer-reaction mass spectrometers (PTR-MS) deployed on a mobile and an airborne platform during MILAGRO. VOC diurnal cycles demonstrate the large influence of vehicle traffic and liquid propane gas (LPG) emissions during the night and photochemical processing during the afternoon. Emission ratios for VOCs and OVOCs relative to CO are derived from early-morning measurements. Average emission ratios for non-oxygenated species relative to CO are on average a factor of {approx}2 higher than measured for US cities. Emission ratios for OVOCs are estimated and compared to literature values the northeastern US and to tunnel studies in California. Positive matrix factorization analysis (PMF) is used to provide insight into VOC sources and processing. Three PMF factors were distinguished by the analysis including the emissions from vehicles, the use of liquid propane gas and the production of secondary VOCs + long-lived species. Emission ratios to CO calculated from the results of PMF analysis are compared to emission ratios calculated directly from measurements. The total PIT-MS signal is summed to estimate the fraction of identified versus unidentified VOC species.

  19. Investigation of the aroma of commercial peach (Prunus persica L. Batsch) types by Proton Transfer Reaction-Mass Spectrometry (PTR-MS) and sensory analysis.

    Science.gov (United States)

    Bianchi, Tiago; Weesepoel, Yannick; Koot, Alex; Iglesias, Ignasi; Eduardo, Iban; Gratacós-Cubarsí, Marta; Guerrero, Luis; Hortós, Maria; van Ruth, Saskia

    2017-09-01

    The aim of this study was to investigate the aroma and sensory profiles of various types of peaches (Prunus persica L. Batsch.). Forty-three commercial cultivars comprising peaches, flat peaches, nectarines, and canning peaches (pavías) were grown over two consecutive harvest years. Fruits were assessed for chemical aroma and sensory profiles. Chemical aroma profile was obtained by proton transfer reaction-mass spectrometry (PTR-MS) and spectral masses were tentatively identified with PTR-Time of Flight-MS (PTR-Tof-MS). Sensory analysis was performed at commercial maturity considering seven aroma/flavor attributes. The four types of peaches showed both distinct chemical aroma and sensory profiles. Flat peaches and canning peaches showed most distinct patterns according to discriminant analysis. The sensory data were related to the volatile compounds by partial least square regression. γ-Hexalactone, γ-octalactone, hotrienol, acetic acid and ethyl acetate correlated positively, and benzeneacetaldehyde, trimethylbenzene and acetaldehyde negatively to the intensities of aroma and ripe fruit sensory scores. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. An example of environmental applications of PTR-MS: characterization of pollution outflow from India and Arabia - biomass burning and fossil fuel combustion

    International Nuclear Information System (INIS)

    Wisthaler, A.; Hansel, A.; Stehr, J.W.; Dickerson, R.R.; Guazzotti, S.A.; Prather, K.A.

    2002-01-01

    Full text: One objective of the Indian Ocean Experiment (INDOEX 1999) was to characterize the chemical composition of pollution outflow from South Asia. Real-time single particle analysis (ATOFMS, Univ. of California- Riverside), CO analysis (Nondispersive Infrared Gas Filter Correlation Photometer, Univ. of Maryland) and fast-response VOC measurements (PTR-MS, Univ. of Innsbruck) measurements were performed onboard the NOAA R/V Ronald H. Brown. Gas phase and aerosol chemical composition of encountered air parcels changed according to their geographic origin traced by backtrajectory analysis (continental air from Arabia and India; maritime air). The relative strength of combustion related pollution sources (biomass burning (BB) vs. fossil fuel (FF) combustion) was determined from the relative abundance of different tracers: acetonitrile (BB), CO (BB and FF), submicron particles containing carbon but no potassium (FF), submicron particles containing carbon and potassium (BB and coal combustion), submicron particles containing carbon, potassium and lithium (coal combustion). Arabian air clearly reflected the signature of fossil fuel combustion, while air from the Indian subcontinent was strongly influenced by biomass burning. (author)

  1. Canopy-scale flux measurements and bottom-up emission estimates of volatile organic compounds from a mixed oak and hornbeam forest in northern Italy

    Directory of Open Access Journals (Sweden)

    W. J. F. Acton

    2016-06-01

    Full Text Available This paper reports the fluxes and mixing ratios of biogenically emitted volatile organic compounds (BVOCs 4 m above a mixed oak and hornbeam forest in northern Italy. Fluxes of methanol, acetaldehyde, isoprene, methyl vinyl ketone + methacrolein, methyl ethyl ketone and monoterpenes were obtained using both a proton-transfer-reaction mass spectrometer (PTR-MS and a proton-transfer-reaction time-of-flight mass spectrometer (PTR-ToF-MS together with the methods of virtual disjunct eddy covariance (using PTR-MS and eddy covariance (using PTR-ToF-MS. Isoprene was the dominant emitted compound with a mean daytime flux of 1.9 mg m−2 h−1. Mixing ratios, recorded 4 m above the canopy, were dominated by methanol with a mean value of 6.2 ppbv over the 28-day measurement period. Comparison of isoprene fluxes calculated using the PTR-MS and PTR-ToF-MS showed very good agreement while comparison of the monoterpene fluxes suggested a slight over estimation of the flux by the PTR-MS. A basal isoprene emission rate for the forest of 1.7 mg m−2 h−1 was calculated using the Model of Emissions of Gases and Aerosols from Nature (MEGAN isoprene emission algorithms (Guenther et al., 2006. A detailed tree-species distribution map for the site enabled the leaf-level emission of isoprene and monoterpenes recorded using gas-chromatography mass spectrometry (GC–MS to be scaled up to produce a bottom-up canopy-scale flux. This was compared with the top-down canopy-scale flux obtained by measurements. For monoterpenes, the two estimates were closely correlated and this correlation improved when the plant-species composition in the individual flux footprint was taken into account. However, the bottom-up approach significantly underestimated the isoprene flux, compared with the top-down measurements, suggesting that the leaf-level measurements were not representative of actual emission rates.

  2. Canopy-scale flux measurements and bottom-up emission estimates of volatile organic compounds from a mixed oak and hornbeam forest in northern Italy

    Science.gov (United States)

    Acton, W. Joe F.; Schallhart, Simon; Langford, Ben; Valach, Amy; Rantala, Pekka; Fares, Silvano; Carriero, Giulia; Tillmann, Ralf; Tomlinson, Sam J.; Dragosits, Ulrike; Gianelle, Damiano; Hewitt, C. Nicholas; Nemitz, Eiko

    2016-06-01

    This paper reports the fluxes and mixing ratios of biogenically emitted volatile organic compounds (BVOCs) 4 m above a mixed oak and hornbeam forest in northern Italy. Fluxes of methanol, acetaldehyde, isoprene, methyl vinyl ketone + methacrolein, methyl ethyl ketone and monoterpenes were obtained using both a proton-transfer-reaction mass spectrometer (PTR-MS) and a proton-transfer-reaction time-of-flight mass spectrometer (PTR-ToF-MS) together with the methods of virtual disjunct eddy covariance (using PTR-MS) and eddy covariance (using PTR-ToF-MS). Isoprene was the dominant emitted compound with a mean daytime flux of 1.9 mg m-2 h-1. Mixing ratios, recorded 4 m above the canopy, were dominated by methanol with a mean value of 6.2 ppbv over the 28-day measurement period. Comparison of isoprene fluxes calculated using the PTR-MS and PTR-ToF-MS showed very good agreement while comparison of the monoterpene fluxes suggested a slight over estimation of the flux by the PTR-MS. A basal isoprene emission rate for the forest of 1.7 mg m-2 h-1 was calculated using the Model of Emissions of Gases and Aerosols from Nature (MEGAN) isoprene emission algorithms (Guenther et al., 2006). A detailed tree-species distribution map for the site enabled the leaf-level emission of isoprene and monoterpenes recorded using gas-chromatography mass spectrometry (GC-MS) to be scaled up to produce a bottom-up canopy-scale flux. This was compared with the top-down canopy-scale flux obtained by measurements. For monoterpenes, the two estimates were closely correlated and this correlation improved when the plant-species composition in the individual flux footprint was taken into account. However, the bottom-up approach significantly underestimated the isoprene flux, compared with the top-down measurements, suggesting that the leaf-level measurements were not representative of actual emission rates.

  3. Emissions of volatile organic compounds inferred from airborne flux measurements over a megacity

    Directory of Open Access Journals (Sweden)

    T. Karl

    2009-01-01

    Full Text Available Toluene and benzene are used for assessing the ability to measure disjunct eddy covariance (DEC fluxes of Volatile Organic Compounds (VOC using Proton Transfer Reaction Mass Spectrometry (PTR-MS on aircraft. Statistically significant correlation between vertical wind speed and mixing ratios suggests that airborne VOC eddy covariance (EC flux measurements using PTR-MS are feasible. City-median midday toluene and benzene fluxes are calculated to be on the order of 14.1±4.0 mg/m2/h and 4.7±2.3 mg/m2/h, respectively. For comparison the adjusted CAM2004 emission inventory estimates toluene fluxes of 10 mg/m2/h along the footprint of the flight-track. Wavelet analysis of instantaneous toluene and benzene measurements during city overpasses is tested as a tool to assess surface emission heterogeneity. High toluene to benzene flux ratios above an industrial district (e.g. 10–15 g/g including the International airport (e.g. 3–5 g/g and a mean flux (concentration ratio of 3.2±0.5 g/g (3.9±0.3 g/g across Mexico City indicate that evaporative fuel and industrial emissions play an important role for the prevalence of aromatic compounds. Based on a tracer model, which was constrained by BTEX (BTEX– Benzene/Toluene/Ethylbenzene/m, p, o-Xylenes compound concentration ratios, the fuel marker methyl-tertiary-butyl-ether (MTBE and the biomass burning marker acetonitrile (CH3CN, we show that a combination of industrial, evaporative fuel, and exhaust emissions account for >87% of all BTEX sources. Our observations suggest that biomass burning emissions play a minor role for the abundance of BTEX compounds in the MCMA (2–13%.

  4. Comparison of VOC measurements made by PTR-MS, adsorbent tubes–GC-FID-MS and DNPH derivatization–HPLC during the Sydney Particle Study, 2012: a contribution to the assessment of uncertainty in routine atmospheric VOC measurements

    Directory of Open Access Journals (Sweden)

    E. Dunne

    2018-01-01

    Full Text Available Understanding uncertainty is essential for utilizing atmospheric volatile organic compound (VOC measurements in robust ways to develop atmospheric science. This study describes an inter-comparison of the VOC data, and the derived uncertainty estimates, measured with three independent techniques (PTR-MS, proton-transfer-reaction mass spectrometry; GC-FID-MS, gas chromatography with flame-ionization and mass spectrometric detection; and DNPH–HPLC, 2,4-dinitrophenylhydrazine derivatization followed by analysis by high-performance liquid chromatography during routine monitoring as part of the Sydney Particle Study (SPS campaign in 2012. Benzene, toluene, C8 aromatics, isoprene, formaldehyde and acetaldehyde were selected for the comparison, based on objective selection criteria from the available data. Bottom-up uncertainty analyses were undertaken for each compound and each measurement system. Top-down uncertainties were quantified via the inter-comparisons. In all seven comparisons, the correlations between independent measurement techniques were high with R2 values with a median of 0.92 (range 0.75–0.98 and small root mean square of the deviations (RMSD of the observations from the regression line with a median of 0.11 (range 0.04–0.23 ppbv. These results give a high degree of confidence that for each comparison the response of the two independent techniques is dominated by the same constituents. The slope and intercept as determined by reduced major axis (RMA regression gives a different story. The slopes varied considerably with a median of 1.25 and a range of 1.16–2.01. The intercepts varied with a median of 0.04 and a range of −0.03 to 0.31 ppbv. An ideal comparison would give a slope of 1.00 and an intercept of 0. Some sources of uncertainty that are poorly quantified by the bottom-up uncertainty analysis method were identified, including: contributions of non-target compounds to the measurement of the target compound for

  5. Comparison of VOC measurements made by PTR-MS, adsorbent tubes-GC-FID-MS and DNPH derivatization-HPLC during the Sydney Particle Study, 2012: a contribution to the assessment of uncertainty in routine atmospheric VOC measurements

    Science.gov (United States)

    Dunne, Erin; Galbally, Ian E.; Cheng, Min; Selleck, Paul; Molloy, Suzie B.; Lawson, Sarah J.

    2018-01-01

    Understanding uncertainty is essential for utilizing atmospheric volatile organic compound (VOC) measurements in robust ways to develop atmospheric science. This study describes an inter-comparison of the VOC data, and the derived uncertainty estimates, measured with three independent techniques (PTR-MS, proton-transfer-reaction mass spectrometry; GC-FID-MS, gas chromatography with flame-ionization and mass spectrometric detection; and DNPH-HPLC, 2,4-dinitrophenylhydrazine derivatization followed by analysis by high-performance liquid chromatography) during routine monitoring as part of the Sydney Particle Study (SPS) campaign in 2012. Benzene, toluene, C8 aromatics, isoprene, formaldehyde and acetaldehyde were selected for the comparison, based on objective selection criteria from the available data. Bottom-up uncertainty analyses were undertaken for each compound and each measurement system. Top-down uncertainties were quantified via the inter-comparisons. In all seven comparisons, the correlations between independent measurement techniques were high with R2 values with a median of 0.92 (range 0.75-0.98) and small root mean square of the deviations (RMSD) of the observations from the regression line with a median of 0.11 (range 0.04-0.23 ppbv). These results give a high degree of confidence that for each comparison the response of the two independent techniques is dominated by the same constituents. The slope and intercept as determined by reduced major axis (RMA) regression gives a different story. The slopes varied considerably with a median of 1.25 and a range of 1.16-2.01. The intercepts varied with a median of 0.04 and a range of -0.03 to 0.31 ppbv. An ideal comparison would give a slope of 1.00 and an intercept of 0. Some sources of uncertainty that are poorly quantified by the bottom-up uncertainty analysis method were identified, including: contributions of non-target compounds to the measurement of the target compound for benzene, toluene and isoprene by

  6. Atmospheric mixing ratios of methyl ethyl ketone (2-butanone in tropical, boreal, temperate and marine environments

    Directory of Open Access Journals (Sweden)

    A. M. Yáñez-Serrano

    2016-09-01

    Full Text Available Methyl ethyl ketone (MEK enters the atmosphere following direct emission from vegetation and anthropogenic activities, as well as being produced by the gas-phase oxidation of volatile organic compounds (VOCs such as n-butane. This study presents the first overview of ambient MEK measurements at six different locations, characteristic of forested, urban and marine environments. In order to understand better the occurrence and behaviour of MEK in the atmosphere, we analyse diel cycles of MEK mixing ratios, vertical profiles, ecosystem flux data, and HYSPLIT back trajectories, and compare with co-measured VOCs. MEK measurements were primarily conducted with proton-transfer-reaction mass spectrometer (PTR-MS instruments. Results from the sites under biogenic influence demonstrate that vegetation is an important source of MEK. The diel cycle of MEK follows that of ambient temperature and the forest structure plays an important role in air mixing. At such sites, a high correlation of MEK with acetone was observed (e.g. r2 = 0.96 for the SMEAR Estonia site in a remote hemiboreal forest in Tartumaa, Estonia, and r2 = 0.89 at the ATTO pristine tropical rainforest site in central Amazonia. Under polluted conditions, we observed strongly enhanced MEK mixing ratios. Overall, the MEK mixing ratios and flux data presented here indicate that both biogenic and anthropogenic sources contribute to its occurrence in the global atmosphere.

  7. PAH diagnostic ratios for the identification of pollution emission sources

    International Nuclear Information System (INIS)

    Tobiszewski, Marek; Namieśnik, Jacek

    2012-01-01

    Polycyclic aromatic hydrocarbon (PAH) diagnostic ratios have recently come into common use as a tool for identifying and assessing pollution emission sources. Some diagnostic ratios are based on parent PAHs, others on the proportions of alkyl-substituted to non-substituted molecules. The ratios are applicable to PAHs determined in different environmental media: air (gas + particle phase), water, sediment, soil, as well as biomonitor organisms such as leaves or coniferous needles, and mussels. These ratios distinguish PAH pollution originating from petroleum products, petroleum combustion and biomass or coal burning. The compounds involved in each ratio have the same molar mass, so it is assumed they have similar physicochemical properties. Numerous studies show that diagnostic ratios change in value to different extents during phase transfers and environmental degradation. The paper reviews applications of diagnostic ratios, comments on their use and specifies their limitations. - Highlights: ► PAH diagnostic ratios may identify pollution coming from petroleum spills, fuel combustion and coal or biomass burning. ► They are sensitive to changes during PAHs environmental fate processes. ► Some diagnostic ratios are of limited value due to fast photodegradation of one of the compounds. - The paper reviews PAH diagnostic ratios that are applied to identify pollution emission originating from petroleum products, fuel combustion or coal and biomass burning.

  8. Development of a novel methodology for indoor emission source identification

    DEFF Research Database (Denmark)

    Han, K.H.; Zhang, J.S.; Knudsen, H.N.

    2011-01-01

    The objective of this study was to develop and evaluate a methodology to identify individual sources of emissions based on the measurements of mixed air samples and the emission signatures of individual materials previously determined by Proton Transfer Reaction-Mass Spectrometry (PTR-MS), an on......-line analytical device. The methodology based on signal processing principles was developed by employing the method of multiple regression least squares (MRLS) and a normalization technique. Samples of nine typical building materials were tested individually and in combination, including carpet, ceiling material...... experiments and investigation are needed for cases where the relative emission rates among different compounds may change over a long-term period....

  9. Source Attribution of Methane Emissions in Northeastern Colorado Using Ammonia to Methane Emission Ratios

    Science.gov (United States)

    Eilerman, S. J.; Neuman, J. A.; Peischl, J.; Aikin, K. C.; Ryerson, T. B.; Perring, A. E.; Robinson, E. S.; Holloway, M.; Trainer, M.

    2015-12-01

    Due to recent advances in extraction technology, oil and natural gas extraction and processing in the Denver-Julesburg basin has increased substantially in the past decade. Northeastern Colorado is also home to over 250 concentrated animal feeding operations (CAFOs), capable of hosting over 2 million head of ruminant livestock (cattle and sheep). Because of methane's high Global Warming Potential, quantification and attribution of methane emissions from oil and gas development and agricultural activity are important for guiding greenhouse gas emission policy. However, due to the co-location of these different sources, top-down measurements of methane are often unable to attribute emissions to a specific source or sector. In this work, we evaluate the ammonia:methane emission ratio directly downwind of CAFOs using a mobile laboratory. Several CAFOs were chosen for periodic study over a 12-month period to identify diurnal and seasonal variation in the emission ratio as well as differences due to livestock type. Using this knowledge of the agricultural ammonia:methane emission ratio, aircraft measurements of ammonia and methane over oil and gas basins in the western US during the Shale Oil and Natural Gas Nexus (SONGNEX) field campaign in March and April 2015 can be used for source attribution of methane emissions.

  10. Driving forces of individual BVOC emissions from a spruce tree in Central Germany; results from a dynamic enclosure study.

    Science.gov (United States)

    Bourtsoukidis, S.; Dittmann, A.; Jacobi, S.; Bonn, B.

    2012-04-01

    We have conducted seasonal ambient and emission measurements of a series of biogenic VOCs such as monoterpenes (MT), sesquiterpenes (SQT), isoprene, methanol, methyl chavicol and acetaldehyde. Therefore a plant enclosure technique was applied in order to investigate a Central European spruce forest and its emissions responses to meteorological and environmental parameters. A healthy ≈15m tall Norway spruce tree was selected and a vegetation enclosure technique was applied from April to November 2011. VOCs are measured by PTR-MS, while samples have also been analyzed with GC-MS (Gas Chromatography - Mass Spectrometry) techniques for intercomparison and identification of individual VOCs. E/N ratio was adjusted at 117Td[2] and the primary ion signal (H3O+) was continuously above 4×10^7cps, implying a high sensitivity to our measurements. Temperature, relative humidity, ozone, photosynthetic active radiation (PAR) and CO2 concentrations were continuously measured inside the plant cuvette. Meteorological and environmental parameters (radiation, atmospheric pressure, wind velocity, wind direction, temperature, O3, relative humidity, soil moisture, precipitation, global radiation, H2O, NO, NO2) were measured by HLUG (Hessian Agency for Environment and Geology) and DWD (German Weather Service), 50 meters away from the measuring site. In a peculiar season, which was characterized by a warm spring (temperature anomaly >40C), a wet summer (precipitation anomaly 126-150%) and an extremely dry autumn (precipitation anomaly monoterpene emission rate variability: model evaluations and sensitivity analyses, Journal of Geophysical Research., 98, 12609-12617, 1993.

  11. Assessing the role of "bottom-up" emissions and simplified chemical mechanisms in reconciling CESM2.0 with TOGA observations from the ORCAS and ATom-2 campaigns

    Science.gov (United States)

    Asher, E.; Emmons, L. K.; Kinnison, D. E.; Tilmes, S.; Hills, A. J.; Hornbrook, R. S.; Stephens, B. B.; Apel, E. C.

    2017-12-01

    Surface albedo and precipitation over the Southern Ocean are sensitive to parameterizations of aerosol formation and cloud dynamics in global climate models. Observations of precursor gases for natural aerosols can help constrain the uncertainty in these parameterizations, if used in conjunction with an appropriately simplified chemical mechanism. We implement current oceanic "bottom-up" emission climatologies of dimethyl sulfide (DMS) and isoprene in CESM2.0 (Lana et al. 2016; Archer et al. 2009) and compare modeled constituents from two separate chemical mechanisms with data obtained from the Trace Organic Gas Analyzer (TOGA) on the O2/N2 Ratios and CO2 Airborne Study in the Southern Ocean (ORCAS) and the Atmospheric Tomography Mission 2 (ATom-2). We use ORCAS measurements of DMS, isoprene, methyl vinyl ketone (MVK) and methacrolein (MACR) from over 10 flights in Jan. - Feb. 2016 as a training dataset to improve "bottom-up" emissions. Thereafter, we evaluate the scaled "top-down" emissions in CESM with TOGA data obtained from the Atmospheric Tomography Mission (ATom-2) in Feb. 2017. Recent laboratory studies at NCAR confirm that TOGA surpasses proton transfer reaction mass spectrometry (PTR-MS) and commercial gas chromatography (GC) instruments with respect to accurate measurements of oxygenated VOCs in low nitrogen oxide (NO) environments, such as MVK and MACR.

  12. Volatile organic compound emissions from the oil and natural gas industry in the Uintah Basin, Utah: oil and gas well pad emissions compared to ambient air composition

    Science.gov (United States)

    Warneke, C.; Geiger, F.; Edwards, P. M.; Dube, W.; Pétron, G.; Kofler, J.; Zahn, A.; Brown, S. S.; Graus, M.; Gilman, J. B.; Lerner, B. M.; Peischl, J.; Ryerson, T. B.; de Gouw, J. A.; Roberts, J. M.

    2014-10-01

    Emissions of volatile organic compounds (VOCs) associated with oil and natural gas production in the Uintah Basin, Utah were measured at a ground site in Horse Pool and from a NOAA mobile laboratory with PTR-MS instruments. The VOC compositions in the vicinity of individual gas and oil wells and other point sources such as evaporation ponds, compressor stations and injection wells are compared to the measurements at Horse Pool. High mixing ratios of aromatics, alkanes, cycloalkanes and methanol were observed for extended periods of time and for short-term spikes caused by local point sources. The mixing ratios during the time the mobile laboratory spent on the well pads were averaged. High mixing ratios were found close to all point sources, but gas well pads with collection and dehydration on the well pad were clearly associated with higher mixing ratios than other wells. The comparison of the VOC composition of the emissions from the oil and natural gas well pads showed that gas well pads without dehydration on the well pad compared well with the majority of the data at Horse Pool, and that oil well pads compared well with the rest of the ground site data. Oil well pads on average emit heavier compounds than gas well pads. The mobile laboratory measurements confirm the results from an emissions inventory: the main VOC source categories from individual point sources are dehydrators, oil and condensate tank flashing and pneumatic devices and pumps. Raw natural gas is emitted from the pneumatic devices and pumps and heavier VOC mixes from the tank flashings.

  13. Emission ratio and isotopic signatures of molecular hydrogen emissions from tropical biomass burning

    Science.gov (United States)

    Haumann, F. A.; Batenburg, A. M.; Pieterse, G.; Gerbig, C.; Krol, M. C.; Röckmann, T.

    2013-09-01

    In this study, we identify a biomass-burning signal in molecular hydrogen (H2) over the Amazonian tropical rainforest. To quantify this signal, we measure the mixing ratios of H2 and several other species as well as the H2 isotopic composition in air samples that were collected in the BARCA (Balanço Atmosférico Regional de Carbono na Amazônia) aircraft campaign during the dry season. We derive a relative H2 emission ratio with respect to carbon monoxide (CO) of 0.31 ± 0.04 ppb ppb-1 and an isotopic source signature of -280 ± 41‰ in the air masses influenced by tropical biomass burning. In order to retrieve a clear source signal that is not influenced by the soil uptake of H2, we exclude samples from the atmospheric boundary layer. This procedure is supported by data from a global chemistry transport model. The ΔH2 / ΔCO emission ratio is significantly lower than some earlier estimates for the tropical rainforest. In addition, our results confirm the lower values of the previously conflicting estimates of the H2 isotopic source signature from biomass burning. These values for the emission ratio and isotopic source signatures of H2 from tropical biomass burning can be used in future bottom-up and top-down approaches aiming to constrain the strength of the biomass-burning source for H2. Hitherto, these two quantities relied only on combustion experiments or on statistical relations, since no direct signal had been obtained from in-situ observations.

  14. Methyl chavicol: characterization of its biogenic emission rate, abundance, and oxidation products in the atmosphere

    Directory of Open Access Journals (Sweden)

    N. C. Bouvier-Brown

    2009-03-01

    Full Text Available We report measurements of ambient atmospheric mixing ratios for methyl chavicol and determine its biogenic emission rate. Methyl chavicol, a biogenic oxygenated aromatic compound, is abundant within and above Blodgett Forest, a ponderosa pine forest in the Sierra Nevada Mountains of California. Methyl chavicol was detected simultaneously by three in-situ instruments – a gas chromatograph with mass spectrometer detector (GC-MS, a proton transfer reaction mass spectrometer (PTR-MS, and a thermal desorption aerosol GC-MS (TAG – and found to be abundant within and above Blodgett Forest. Methyl chavicol atmospheric mixing ratios are strongly correlated with 2-methyl-3-buten-2-ol (MBO, a light- and temperature-dependent biogenic emission from the ponderosa pine trees at Blodgett Forest. Scaling from this correlation, methyl chavicol emissions account for 4–68% of the carbon mass emitted as MBO in the daytime, depending on the season. From this relationship, we estimate a daytime basal emission rate of 0.72–10.2 μgCg−1 h−1, depending on needle age and seasonality. We also present the first observations of its oxidation products (4-methoxybenzaldehyde and 4-methyoxy benzene acetaldehyde in the ambient atmosphere. Methyl chavicol is a major essential oil component of many plant species. This work suggests that methyl chavicol plays a significant role in the atmospheric chemistry of Blodgett Forest, and potentially other sites, and should be included explicitly in both biogenic volatile organic carbon emission and atmospheric chemistry models.

  15. Seasonality of isoprenoid emissions from a primary rainforest in central Amazonia

    Directory of Open Access Journals (Sweden)

    E. G. Alves

    2016-03-01

    Full Text Available Tropical rainforests are an important source of isoprenoid and other volatile organic compound (VOC emissions to the atmosphere. The seasonal variation of these compounds is however still poorly understood. In this study, vertical profiles of mixing ratios of isoprene, total monoterpenes and total sesquiterpenes, were measured within and above the canopy, in a primary rainforest in central Amazonia, using a proton transfer reaction – mass spectrometer (PTR-MS. Fluxes of these compounds from the canopy into the atmosphere were estimated from PTR-MS measurements by using an inverse Lagrangian transport model. Measurements were carried out continuously from September 2010 to January 2011, encompassing the dry and wet seasons. Mixing ratios were higher during the dry (isoprene – 2.68 ± 0.9 ppbv, total monoterpenes – 0.67 ± 0.3 ppbv; total sesquiterpenes – 0.09 ± 0.07 ppbv than the wet season (isoprene – 1.66 ± 0.9 ppbv, total monoterpenes – 0.47 ± 0.2 ppbv; total sesquiterpenes – 0.03 ± 0.02 ppbv for all compounds. Ambient air temperature and photosynthetically active radiation (PAR behaved similarly. Daytime isoprene and total monoterpene mixing ratios were highest within the canopy, rather than near the ground or above the canopy. By comparison, daytime total sesquiterpene mixing ratios were highest near the ground. Daytime fluxes varied significantly between seasons for all compounds. The maximums for isoprene (2.53 ± 0.5 µmol m−2 h−1 and total monoterpenes (1.77 ± 0.05 µmol m−2 h−1 were observed in the late dry season, whereas the maximum for total sesquiterpenes was found during the dry-to-wet transition season (0.77 ± 0.1 µmol m−2 h−1. These flux estimates suggest that the canopy is the main source of isoprenoids emitted into the atmosphere for all seasons. However, uncertainties in turbulence parameterization near the ground could affect estimates of fluxes that come from the ground. Leaf

  16. Seasonality of isoprenoid emissions from a primary rainforest in central Amazonia

    Science.gov (United States)

    Alves, Eliane G.; Jardine, Kolby; Tota, Julio; Jardine, Angela; Yãnez-Serrano, Ana Maria; Karl, Thomas; Tavares, Julia; Nelson, Bruce; Gu, Dasa; Stavrakou, Trissevgeni; Martin, Scot; Artaxo, Paulo; Manzi, Antonio; Guenther, Alex

    2016-03-01

    Tropical rainforests are an important source of isoprenoid and other volatile organic compound (VOC) emissions to the atmosphere. The seasonal variation of these compounds is however still poorly understood. In this study, vertical profiles of mixing ratios of isoprene, total monoterpenes and total sesquiterpenes, were measured within and above the canopy, in a primary rainforest in central Amazonia, using a proton transfer reaction - mass spectrometer (PTR-MS). Fluxes of these compounds from the canopy into the atmosphere were estimated from PTR-MS measurements by using an inverse Lagrangian transport model. Measurements were carried out continuously from September 2010 to January 2011, encompassing the dry and wet seasons. Mixing ratios were higher during the dry (isoprene - 2.68 ± 0.9 ppbv, total monoterpenes - 0.67 ± 0.3 ppbv; total sesquiterpenes - 0.09 ± 0.07 ppbv) than the wet season (isoprene - 1.66 ± 0.9 ppbv, total monoterpenes - 0.47 ± 0.2 ppbv; total sesquiterpenes - 0.03 ± 0.02 ppbv) for all compounds. Ambient air temperature and photosynthetically active radiation (PAR) behaved similarly. Daytime isoprene and total monoterpene mixing ratios were highest within the canopy, rather than near the ground or above the canopy. By comparison, daytime total sesquiterpene mixing ratios were highest near the ground. Daytime fluxes varied significantly between seasons for all compounds. The maximums for isoprene (2.53 ± 0.5 µmol m-2 h-1) and total monoterpenes (1.77 ± 0.05 µmol m-2 h-1) were observed in the late dry season, whereas the maximum for total sesquiterpenes was found during the dry-to-wet transition season (0.77 ± 0.1 µmol m-2 h-1). These flux estimates suggest that the canopy is the main source of isoprenoids emitted into the atmosphere for all seasons. However, uncertainties in turbulence parameterization near the ground could affect estimates of fluxes that come from the ground. Leaf phenology seemed to be an important driver of seasonal

  17. Characterization of fresh and aged organic aerosol emissions from meat charbroiling

    Directory of Open Access Journals (Sweden)

    C. Kaltsonoudis

    2017-06-01

    Full Text Available Cooking emissions can be a significant source of fine particulate matter in urban areas. In this study the aerosol- and gas-phase emissions from meat charbroiling were characterized. Greek souvlakia with pork were cooked using a commercial charbroiler and a fraction of the emissions were introduced into a smog chamber where after a characterization phase they were exposed to UV illumination and oxidants. The particulate and gas phases were characterized by a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS and a proton-transfer-reaction mass spectrometer (PTR-MS correspondingly. More than 99 % of the aerosol emitted was composed of organic compounds, while black carbon (BC contributed 0.3 % and the inorganic species less than 0.5 % of the total aerosol mass. The initial O  :  C ratio was approximately 0.09 and increased up to 0.30 after a few hours of chemical aging (exposures of 1010 molecules cm−3 s for OH and 100 ppb h for ozone. The initial and aged AMS spectra differed considerably (θ =  27°. Ambient measurements were also conducted during Fat Thursday in Patras, Greece, when traditionally meat is charbroiled everywhere in the city. Positive matrix factorization (PMF revealed that cooking organic aerosol (COA reached up to 85 % of the total OA from 10:00 to 12:00 LST that day. The ambient COA factor in two major Greek cities had a mass spectrum during spring and summer similar to the aged meat charbroiling emissions. In contrast, the ambient COA factor during winter resembled strongly the fresh laboratory meat charbroiling emissions.

  18. Evaluating the effectiveness of joint emission control policies on the reduction of ambient VOCs: Implications from observation during the 2014 APEC summit in suburban Beijing

    Science.gov (United States)

    Li, Kun; Li, Junling; Wang, Weigang; Tong, Shengrui; Liggio, John; Ge, Maofa

    2017-09-01

    Ambient volatile organic compounds (VOCs) at a suburban Beijing site were on-line detected using proton transfer reaction-mass spectrometry (PTR-MS) during autumn of 2014, near the location of the Asia-Pacific Economic Cooperation (APEC) summit. During the APEC summit, the Chinese government enacted strict emission control policies. It was found that VOC concentrations only slightly decreased during the first emission control period (EC I), when control policies were performed in Beijing and 5 cities along the Tai-hang Mountains. However, most of the VOCs (10 out of 12 non-biogenic species) significantly decreased (more than 40%) during the second emission control period (EC II), when control policies were carried out in 16 cities including Beijing, Tianjin, 8 cities of Hebei province and 6 cities of Shandong province. Also the ratio of toluene and benzene decreased during EC II, likely because the emission control policies changed the proportions of different anthropogenic sources. Using the positive matrix factorization (PMF) source apportionment method, five factors are analyzed: (1) vehicle + fuel, (2) solvent, (3) biomass burning, (4) secondary, and (5) background + long-lived. Among them, vehicle + fuel, solvent and biomass burning contribute most of the VOCs concentrations (60%-80%) during the polluted periods and are affected most by emission control policies. During EC II, the reductions of vehicle + fuel, solvent, biomass burning and secondary species were all no less than 50%. Overall, when emission control policies were carried out in many North China Plain (NCP) cities (i.e. EC II), the VOC concentrations of suburban Beijing markedly decreased. This indicates the cross-regional joint-control policies have a large influence on reductions of organic gas species. The findings of this study have vital implications for helping formulate effective emission control policies in China and other countries.

  19. Non-methane organic gas emissions from biomass burning: identification, quantification, and emission factors from PTR-ToF during the FIREX 2016 laboratory experiment

    Science.gov (United States)

    Koss, Abigail R.; Sekimoto, Kanako; Gilman, Jessica B.; Selimovic, Vanessa; Coggon, Matthew M.; Zarzana, Kyle J.; Yuan, Bin; Lerner, Brian M.; Brown, Steven S.; Jimenez, Jose L.; Krechmer, Jordan; Roberts, James M.; Warneke, Carsten; Yokelson, Robert J.; de Gouw, Joost

    2018-03-01

    Volatile and intermediate-volatility non-methane organic gases (NMOGs) released from biomass burning were measured during laboratory-simulated wildfires by proton-transfer-reaction time-of-flight mass spectrometry (PTR-ToF). We identified NMOG contributors to more than 150 PTR ion masses using gas chromatography (GC) pre-separation with electron ionization, H3O+ chemical ionization, and NO+ chemical ionization, an extensive literature review, and time series correlation, providing higher certainty for ion identifications than has been previously available. Our interpretation of the PTR-ToF mass spectrum accounts for nearly 90 % of NMOG mass detected by PTR-ToF across all fuel types. The relative contributions of different NMOGs to individual exact ion masses are mostly similar across many fires and fuel types. The PTR-ToF measurements are compared to corresponding measurements from open-path Fourier transform infrared spectroscopy (OP-FTIR), broadband cavity-enhanced spectroscopy (ACES), and iodide ion chemical ionization mass spectrometry (I- CIMS) where possible. The majority of comparisons have slopes near 1 and values of the linear correlation coefficient, R2, of > 0.8, including compounds that are not frequently reported by PTR-MS such as ammonia, hydrogen cyanide (HCN), nitrous acid (HONO), and propene. The exceptions include methylglyoxal and compounds that are known to be difficult to measure with one or more of the deployed instruments. The fire-integrated emission ratios to CO and emission factors of NMOGs from 18 fuel types are provided. Finally, we provide an overview of the chemical characteristics of detected species. Non-aromatic oxygenated compounds are the most abundant. Furans and aromatics, while less abundant, comprise a large portion of the OH reactivity. The OH reactivity, its major contributors, and the volatility distribution of emissions can change considerably over the course of a fire.

  20. Non-methane organic gas emissions from biomass burning: identification, quantification, and emission factors from PTR-ToF during the FIREX 2016 laboratory experiment

    Directory of Open Access Journals (Sweden)

    A. R. Koss

    2018-03-01

    Full Text Available Volatile and intermediate-volatility non-methane organic gases (NMOGs released from biomass burning were measured during laboratory-simulated wildfires by proton-transfer-reaction time-of-flight mass spectrometry (PTR-ToF. We identified NMOG contributors to more than 150 PTR ion masses using gas chromatography (GC pre-separation with electron ionization, H3O+ chemical ionization, and NO+ chemical ionization, an extensive literature review, and time series correlation, providing higher certainty for ion identifications than has been previously available. Our interpretation of the PTR-ToF mass spectrum accounts for nearly 90 % of NMOG mass detected by PTR-ToF across all fuel types. The relative contributions of different NMOGs to individual exact ion masses are mostly similar across many fires and fuel types. The PTR-ToF measurements are compared to corresponding measurements from open-path Fourier transform infrared spectroscopy (OP-FTIR, broadband cavity-enhanced spectroscopy (ACES, and iodide ion chemical ionization mass spectrometry (I− CIMS where possible. The majority of comparisons have slopes near 1 and values of the linear correlation coefficient, R2, of  >  0.8, including compounds that are not frequently reported by PTR-MS such as ammonia, hydrogen cyanide (HCN, nitrous acid (HONO, and propene. The exceptions include methylglyoxal and compounds that are known to be difficult to measure with one or more of the deployed instruments. The fire-integrated emission ratios to CO and emission factors of NMOGs from 18 fuel types are provided. Finally, we provide an overview of the chemical characteristics of detected species. Non-aromatic oxygenated compounds are the most abundant. Furans and aromatics, while less abundant, comprise a large portion of the OH reactivity. The OH reactivity, its major contributors, and the volatility distribution of emissions can change considerably over the course of a fire.

  1. Volatile organic compound emissions from the oil and natural gas industry in the Uinta Basin, Utah: point sources compared to ambient air composition

    Science.gov (United States)

    Warneke, C.; Geiger, F.; Edwards, P. M.; Dube, W.; Pétron, G.; Kofler, J.; Zahn, A.; Brown, S. S.; Graus, M.; Gilman, J.; Lerner, B.; Peischl, J.; Ryerson, T. B.; de Gouw, J. A.; Roberts, J. M.

    2014-05-01

    The emissions of volatile organic compounds (VOCs) associated with oil and natural gas production in the Uinta Basin, Utah were measured at a ground site in Horse Pool and from a NOAA mobile laboratory with PTR-MS instruments. The VOC compositions in the vicinity of individual gas and oil wells and other point sources such as evaporation ponds, compressor stations and injection wells are compared to the measurements at Horse Pool. High mixing ratios of aromatics, alkanes, cycloalkanes and methanol were observed for extended periods of time and short-term spikes caused by local point sources. The mixing ratios during the time the mobile laboratory spent on the well pads were averaged. High mixing ratios were found close to all point sources, but gas wells using dry-gas collection, which means dehydration happens at the well, were clearly associated with higher mixing ratios than other wells. Another large source was the flowback pond near a recently hydraulically re-fractured gas well. The comparison of the VOC composition of the emissions from the oil and natural gas wells showed that wet gas collection wells compared well with the majority of the data at Horse Pool and that oil wells compared well with the rest of the ground site data. Oil wells on average emit heavier compounds than gas wells. The mobile laboratory measurements confirm the results from an emissions inventory: the main VOC source categories from individual point sources are dehydrators, oil and condensate tank flashing and pneumatic devices and pumps. Raw natural gas is emitted from the pneumatic devices and pumps and heavier VOC mixes from the tank flashings.

  2. Simultaneous measurement of quantum yield ratio and absorption ratio between acceptor and donor by linearly unmixing excitation-emission spectra.

    Science.gov (United States)

    Zhang, C; Lin, F; DU, M; Qu, W; Mai, Z; Qu, J; Chen, T

    2018-02-13

    Quantum yield ratio (Q A /Q D ) and absorption ratio (K A /K D ) in all excitation wavelengths used between acceptor and donor are indispensable to quantitative fluorescence resonance energy transfer (FRET) measurement based on linearly unmixing excitation-emission spectra (ExEm-spFRET). We here describe an approach to simultaneously measure Q A /Q D and K A /K D values by linearly unmixing the excitation-emission spectra of at least two different donor-acceptor tandem constructs with unknown FRET efficiency. To measure the Q A /Q D and K A /K D values of Venus (V) to Cerulean (C), we used a wide-field fluorescence microscope to image living HepG2 cells separately expressing each of four different C-V tandem constructs at different emission wavelengths with 435 nm and 470 nm excitation respectively to obtain the corresponding excitation-emission spectrum (S DA ). Every S DA was linearly unmixed into the contributions (weights) of three excitation-emission spectra of donor (W D ) and acceptor (W A ) as well as donor-acceptor sensitisation (W S ). Plot of W S /W D versus W A /W D for the four C-V plasmids from at least 40 cells indicated a linear relationship with 1.865 of absolute intercept (Q A /Q D ) and 0.273 of the reciprocal of slope (K A /K D ), which was validated by quantitative FRET measurements adopting 1.865 of Q A /Q D and 0.273 of K A /K D for C32V, C5V, CVC and VCV constructs respectively in living HepG2 cells. © 2018 The Authors Journal of Microscopy © 2018 Royal Microscopical Society.

  3. Forecasting the Allocation Ratio of Carbon Emission Allowance Currency for 2020 and 2030 in China

    Directory of Open Access Journals (Sweden)

    Shihong Zeng

    2016-07-01

    Full Text Available Many countries and scholars have used various strategies to improve and optimize the allocation ratios for carbon emission allowances. This issue is more urgent for China due to the uneven development across the country. This paper proposes a new method that divides low-carbon economy development processes into two separate periods: from 2020 to 2029 and from 2030 to 2050. These two periods have unique requirements and emissions reduction potential; therefore, they must involve different allocation methods, so that reduction behaviors do not stall the development of regional low-carbon economies. During the first period, a more deterministic economic development approach for the carbon emission allowance allocation ratio should be used. During the second period, more adaptive and optimized policy guidance should be employed. We developed a low-carbon economy index evaluation system using the entropy weight method to measure information filtering levels. We conducted vector autoregressive correlation tests, consulted 60 experts for the fuzzy analytic hierarchy process, and we conducted max-min standardized data processing tests. This article presents first- and second-period carbon emission allowance models in combination with a low-carbon economy index evaluation system. Finally, we forecast reasonable carbon emission allowance allocation ratios for China for the periods starting in 2020 and 2030. A good allocation ratio for the carbon emission allowance can help boost China’s economic development and help the country reach its energy conservation and emissions reduction goals.

  4. Volatile Organic Compound (VOC) Emissions from Dairy Cows and Their Waste

    Science.gov (United States)

    Shaw, S.; Holzinger, R.; Mitloehner, F.; Goldstein, A.

    2005-12-01

    Biogenic VOCs are typically defined as those directly emitted from plants, but approximately 6% of global net primary production is consumed by cattle that carry out enteric fermentation and then emit VOCs that could also be considered biogenic. Current regulatory estimates suggest that dairy cattle in central California emit VOCs at rates comparable to those from passenger vehicles in the region, and thus contribute significantly to the extreme non-attainment of ozone standards there. We report PTR-MS measurements of ammonia and VOCs, and cavity-enhanced-absorption gas analyzer (Los Gatos Research, Inc.) measurements of CH4, emitted from dairy cattle in various stages of pregnancy/lactation and their waste. Experiments were conducted in chambers at UC Davis that simulate freestall cow housing conditions. CH4 fluxes ranged from 125-374 lb/cow/year. The compounds with the highest fluxes from '3 cows+waste' treatments were: ammonia (1-18), methanol (0-2.3), acetone+propanal (0.2-0.7), dimethylsulfide (0-0.4), and mass 109 (likely ID = p-cresol; 0-0.3) in lb/cow/year. Mass 60 (likely ID = trimethylamine) and acetic acid were also abundant. There were 10s of additional compounds with detectable, but small, emissions. A few compounds that were likely emitted (i.e. ethanol, formaldehyde, and dimethylamine) were not quantified by the PTR-MS. The total flux for all measured organic gases (TOG = CH4 + PTR-MS VOCs(including acetone+propanal)) averaged 246±45 lb/cow/year for '3 cows+waste' treatments, and was dominated by methane (>98%). TOG flux for 'waste only' treatments averaged 1.1±0.1 lb/cow/year, and was instead dominated by VOC (>84%). The PTR-MS VOCs as a percent of TOG (0.6±0.2%) emitted from '3 cows+waste' treatments in chamber conditions was a factor of 10 smaller than that currently estimated by the California Air Resources Board. In addition, the ozone forming potentials of the most abundant VOCs are only about 10% those of typical combustion or plant

  5. Emission factor ratios, SOA mass yields, and the impact of vehicular emissions on SOA formation

    Science.gov (United States)

    Ensberg, J. J.; Hayes, P. L.; Jimenez, J. L.; Gilman, J. B.; Kuster, W. C.; de Gouw, J. A.; Holloway, J. S.; Gordon, T. D.; Jathar, S.; Robinson, A. L.; Seinfeld, J. H.

    2014-03-01

    The underprediction of ambient secondary organic aerosol (SOA) levels by current atmospheric models in urban areas is well established, yet the cause of this underprediction remains elusive. Likewise, the relative contribution of emissions from gasoline- and diesel-fueled vehicles to the formation of SOA is generally unresolved. We investigate the source of these two discrepancies using data from the 2010 CalNex experiment carried out in the Los Angeles Basin (Ryerson et al., 2013). Specifically, we use gas-phase organic mass (GPOM) and CO emission factors in conjunction with measured enhancements in oxygenated organic aerosol (OOA) relative to CO to quantify the significant lack of closure between expected and observed organic aerosol concentrations attributable to fossil-fuel emissions. Two possible conclusions emerge from the analysis to yield consistency with the ambient data: (1) vehicular emissions are not a dominant source of anthropogenic fossil SOA in the Los Angeles Basin, or (2) the ambient SOA mass yields used to determine the SOA formation potential of vehicular emissions are substantially higher than those derived from laboratory chamber studies.

  6. BAT AGN Spectroscopic Survey - III. An Observed Link Between AGN Eddington Ratio and Narrow-Emission-Line Ratios

    Science.gov (United States)

    Oh, Kyuseok; Schawinski, Kevin; Koss, Michael; Trakhtenbrot, Benny; Lamperti, Isabella; Ricci, Claudio; Mushotzky, Richard; Veilleux, Sylvain; Berney, Simon; Crenshaw, D. Michael; hide

    2016-01-01

    We investigate the observed relationship between black hole mass (M(sub BH)), bolometric luminosity (L(sub bol)) and Eddington ratio (lambda(sub Edd)) with optical emission-line ratios ([N II] lambda6583/Halpha, [S II]lambda-lamda6716, 6731/Halpha, [O I] lamda6300/Halpha, [O III] lamda5007/Hbeta, [Ne III] lamda3869/Hbeta and He II lamda4686/Hbeta) of hard X-ray-selected active galactic nuclei (AGN) from the BAT AGN Spectroscopic Survey. We show that the [N II] lamda6583/Halpha ratio exhibits a significant correlation with lamda(sub Edd) (R(sub Pear) = -0.44, p-value 3 x 10(exp. -13) sigma = 0.28 dex), and the correlation is not solely driven by M(sub BH) or L(sub bol). The observed correlation between [N II] lamda6583/Halpha ratio and M(sub BH) is stronger than the correlation with L(sub bol), but both are weaker than the lamda(sub Edd) correlation. This implies that the large-scale narrow lines of AGN host galaxies carry information about the accretion state of the AGN central engine. We propose that [N II] lamda6583/Halpha is a useful indicator of Eddington ratio with 0.6 dex of rms scatter, and that it can be used to measure lambda(sub Edd) and thus M(sub BH) from the measured L(sub bol), even for high-redshift obscured AGN. We briefly discuss possible physical mechanisms behind this correlation, such as the mass-metallicity relation, X-ray heating, and radiatively driven outflows.

  7. A new method of organizing spectral line intensity ratio fluctuations of nightglow emissions

    International Nuclear Information System (INIS)

    Thelin, B.

    1986-02-01

    In this paper a new kind of linearization effect between the atmospheric night airglow emissions is presented. The same kind of linearization effect has previously been studied with spectrochemical light sources together with a spectrometer. A linear graph was obtained for atomic spectral lines and vibrational bandspectra when the spectral line intensity ratio fluctuations were plotted versus the photon energies of these emissions. To study this effect data from a number of different photometer investigations of night airglow emissions at different times and places have been used. (author)

  8. Emission ratio and isotopic signatures of molecular hydrogen emissions from tropical biomass burning

    NARCIS (Netherlands)

    Haumann, F.A.; Batenburg, A.M.; Pieterse, G.; Gerbig, C.; Krol, M.C.; Rockmann, T.

    2013-01-01

    In this study, we identify a biomass-burning signal in molecular hydrogen (H-2) over the Amazonian tropical rainforest. To quantify this signal, we measure the mixing ratios of H-2 and several other species as well as the H-2 isotopic composition in air samples that were collected in the BARCA

  9. Emission ratio and isotopic signatures of molecular hydrogen emissions from tropical biomass burning

    NARCIS (Netherlands)

    Haumann, F.A.; Batenburg, A.M.; Pieterse, G.; Gerbig, C; Krol, M.C.; Röckmann, T.

    2013-01-01

    In this study, we identify a biomass-burning signal in molecular hydrogen (H2) over the Amazonian tropical rainforest. To quantify this signal, we measure the mixing ratios of H2 and several other species as well as the H2 isotopic composition in air samples that were collected in the BARCA (Balanço

  10. Synthetic nebular emission from massive galaxies - I: origin of the cosmic evolution of optical emission-line ratios

    Science.gov (United States)

    Hirschmann, Michaela; Charlot, Stephane; Feltre, Anna; Naab, Thorsten; Choi, Ena; Ostriker, Jeremiah P.; Somerville, Rachel S.

    2017-12-01

    Galaxies occupy different regions of the [O III]λ5007/H β-versus-[N II]λ6584/H α emission-line ratio diagram in the distant and local Universe. We investigate the origin of this intriguing result by modelling self-consistently, for the first time, nebular emission from young stars, accreting black holes (BHs) and older, post-asymptotic giant branch (post-AGB) stellar populations in galaxy formation simulations in a full cosmological context. In post-processing, we couple new-generation nebular-emission models with high-resolution, cosmological zoom-in simulations of massive galaxies to explore which galaxy physical properties drive the redshift evolution of the optical-line ratios [O III]λ5007/H β, [N II]λ6584/H α, [S II]λλ6717, 6731/H α and [O I]λ6300/H α. The line ratios of simulated galaxies agree well with observations of both star-forming and active local Sloan Digital Sky Survey galaxies. Towards higher redshifts, at fixed galaxy stellar mass, the average [O III]/H β is predicted to increase and [N II]/H α, [S II]/H α and [O I]/H α to decrease - widely consistent with observations. At fixed stellar mass, we identify star formation history, which controls nebular emission from young stars via the ionization parameter, as the primary driver of the cosmic evolution of [O III]/H β and [N II]/H α. For [S II]/H α and [O I]/H α, this applies only to redshifts greater than z = 1.5, the evolution at lower redshift being driven in roughly equal parts by nebular emission from active galactic nuclei and post-AGB stellar populations. Instead, changes in the hardness of ionizing radiation, ionized-gas density, the prevalence of BH accretion relative to star formation and the dust-to-metal mass ratio (whose impact on the gas-phase N/O ratio we model at fixed O/H) play at most a minor role in the cosmic evolution of simulated galaxy line ratios.

  11. Mid-Infrared Emission Features in the ISM: Feature-to-Features Flux Ratios

    Science.gov (United States)

    Lu, N. Y.

    1998-01-01

    Using a limited, but representative sample of sources in the ISM of our Galaxy with published spectra from the Infrared Space Observatory, we analyze flux ratios between the major mid-IR emission features (EFs) centered around 6.2, 7.7, 8.6 and 11.3 mu, respectively.

  12. Luminosity dependence in the ratio of X-ray to infrared emission of QSOs

    International Nuclear Information System (INIS)

    Worrall, D.M.

    1987-01-01

    The correlation of X-ray and near-infrared luminosity is studied for a sample of radio-quiet QSOs. The X-ray to infrared ratio is found to decrease as the infrared luminosity increases. No preference is found between the correlations of X-ray luminosity with optical or infrared luminosity. This implies that optical and infrared emission are equally good predictors of X-ray emission. Source models which directly link infrared and X-ray emission are discussed, and a preference is found for a specific synchrotron self-Compton model. This model predicts the correct luminosity dependence of the X-ray to infrared ratio if certain conditions apply. 55 references

  13. A new method of organizing spectral line intensity ratio fluctuations of auroral emissions

    International Nuclear Information System (INIS)

    Thelin, B.

    1986-02-01

    In this paper a new kind of linearization effect between the atmospheric auroral emissions is presented. The same kind of linearization effect has previously been found in nightglow emissions from photometer measurements and in the spectrochemical field from studies of optical light sources. Linear graphs have been obtained for atomic spectral lines and vibrational bandspectra when the spectral line ratio fluctuations were plotted versus the photon energies of these emissions. This new effect has been studied with a spectrophotometer in auroral emissions, where linear graphs have been obtained on different auroral occasions. By doing such studies of auroral light it is possible to see the importance of the inelastic scattering cross section between electrons - atoms and electrons - molecules. In this way it has shown to be possible to determine the mean energy of the interacting thermal electrons that are active in the different auroral phases. (author)

  14. The ratio of effective building height to street width governs dispersion of local vehicle emissions

    Science.gov (United States)

    Schulte, Nico; Tan, Si; Venkatram, Akula

    2015-07-01

    Analysis of data collected in street canyons located in Hanover, Germany and Los Angeles, USA, suggests that street-level concentrations of vehicle-related pollutants can be estimated with a model that assumes that vertical turbulent transport of emissions dominates the governing processes. The dispersion model relates surface concentrations to traffic flow rate, the effective aspect ratio of the street, and roof level turbulence. The dispersion model indicates that magnification of concentrations relative to those in the absence of buildings is most sensitive to the aspect ratio of the street, which is the ratio of the effective height of the buildings on the street to the width of the street. This result can be useful in the design of transit oriented developments that increase building density to reduce emissions from transportation.

  15. A dual tracer ratio method for comparative emission measurements in an experimental dairy housing

    Science.gov (United States)

    Mohn, Joachim; Zeyer, Kerstin; Keck, Margret; Keller, Markus; Zähner, Michael; Poteko, Jernej; Emmenegger, Lukas; Schrade, Sabine

    2018-04-01

    Agriculture, and in particular dairy farming, is an important source of ammonia (NH3) and non-carbon dioxide greenhouse gas (GHG) emissions. This calls for the development and quantification of effective mitigation strategies. Our study presents the implementation of a dual tracer ratio method in a novel experimental dairy housing with two identical, but spatially separated housing areas. Modular design and flexible floor elements allow the assessment of structural, process engineering and organisational abatement measures at practical scale. Thereby, the emission reduction potential of specific abatement measures can be quantified in relation to a reference system. Emissions in the naturally ventilated housing are determined by continuous dosing of two artificial tracers (sulphur hexafluoride SF6, trifluoromethylsulphur pentafluoride SF5CF3) and their real-time detection in the ppt range with an optimized GC-ECD method. The two tracers are dosed into different experimental sections, which enables the independent assessment of both housing areas. Mass flow emissions of NH3 and GHGs are quantified by areal dosing of tracer gases and multipoint sampling as well as real-time analysis of both tracer and target gases. Validation experiments demonstrate that the technique is suitable for both areal and point emission sources and achieves an uncertainty of less than 10% for the mass emissions of NH3, methane (CH4) and carbon dioxide (CO2), which is superior to other currently available methods. Comparative emission measurements in this experimental dairy housing will provide reliable, currently unavailable information on emissions for Swiss dairy farming and demonstrate the reduction potential of mitigation measures for NH3, GHGs and potentially other pollutants.

  16. Direct isotope ratio measurement of uranium metal by emission spectrometry on a laser-produced plasma

    International Nuclear Information System (INIS)

    Pietsch, W.; Petit, A.; Briand, A.

    1995-01-01

    The method of Optical Emission Spectrometry on a Laser-Produced Plasma (OES/LPP) at reduced pressure has been studied for the determination of the uranium isotope ratio ( 235 U/ 238 U). Spectral profiles of the investigated transition U-II 424.437 nm show the possibility to obtain an isotopic spectral resolution in a laser-produced plasma under exactly defined experimental conditions. Spectroscopic data and results are presented. (author)

  17. Can Coronene and/or Benzo(a)pyrene/Coronene ratio act as unique markers for vehicle emission?

    International Nuclear Information System (INIS)

    Shen, Guofeng; Chen, Yuanchen; Wei, Siye; Fu, Xiaofang; Ding, Aijun; Wu, Haisuo; Tao, Shu

    2014-01-01

    Coronene is a high molecular weight polycyclic aromatic hydrocarbon with seven aromatic rings. It, more specifically a lower ratio of Benzo[a]pyrene to Coronone (BaP/COR), is suggested as a marker for vehicle emission. In the present study, emissions of Coronene were measured from residential combustions of wood, crop straw, and pellets. The detection of COR in non-vehicle emission sources, and comparable BaP/COR ratios between the solid fuel combustion and vehicle emissions indicated that the generality of COR or the BaP/COR ratio as markers for the vehicle emission would be questionable, especially for the area where solid fuel combustion dominated the PAHs emission. Highlights: • Coronene alone is not a unique marker for vehicle emission. • The specific ratio, BaP/Coronene, could be very high for gasoline emission. • The use of a specific ratio, BaP/Coronene, as a marker is debatable. -- Coronene alone is not a unique tracer for vehicle emission and the use of specific Benzo[a]pyrene to Coronene ratio needs more evaluation studies

  18. Comparison of emission inventory and ambient concentration ratios of CO, NMOG, and NOx in California South Coast Air Basin

    International Nuclear Information System (INIS)

    Fujita, E.M.; Croes, B.E.; Bennett, C.L.; Lawson, D.R.; Lurmann, F.W.; Main, H.H.

    1992-01-01

    In the present study, the author performed a top-down validation of the reactive organic gas and carbon monoxide emission inventories for California's South Coast Air Basin by comparing speciation profiles for nonmethane organic gases (NMOG) and ratios of CO/NO x and NMOG/NO x derived from early-morning (0700 to 0800) ambient measurements taken during the 1987 Southern California Air Quality Study with the corresponding ratios and speciation profiles derived from day-specific, hourly, gridded emission inventories. Twenty separate comparisons were considered for each ratio, each representing a different combination of season, emission category, and spatial and temporal averaging of emissions. It was determined that the most appropriate comparison in summer was ambient pollutant ratios with ratios derived from morning on-road motrovehicle emission inventories, and in the fall, ambient ratios with ratios derived from overnight on-road motor vehicle emission inventories with some contribution from overnight stationary-source NO x emission inventories. From these comparisons, the ambient CO/CO x and NMOG/NO x ratios are about 1.5 and 2 to 2.5 times higher, respectively, than the corresponding inventory ratios. On the assumption that inventories of NO x emissions are reasonably correct, these results indicate that on-road motor vehicle CO and NMOG emissions are significantly underestimated. Comparisons of measured CO, NMOG, and NO x concentrations and CO/NO x and NMOG/NO x ratios with air quality model predictions obtained by the California Air Resources Board show similar differences

  19. Biogenic Volatile Organic Compound (BVOC) emissions from agricultural crop species: is guttation a possible source for methanol emissions following light/dark transition ?

    Science.gov (United States)

    Mozaffar, Ahsan; Amelynck, Crist; Bachy, Aurélie; Digrado, Anthony; Delaplace, Pierre; du Jardin, Patrick; Fauconnier, Marie-Laure; Schoon, Niels; Aubinet, Marc; Heinesch, Bernard

    2015-04-01

    In the framework of the CROSTVOC (CROp STress VOC) project, the exchange of biogenic volatile organic compounds (BVOCs) between two important agricultural crop species, maize and winter wheat, and the atmosphere has recently been measured during an entire growing season by using the eddy covariance technique. Because of the co-variation of BVOC emission drivers in field conditions, laboratory studies were initiated in an environmental chamber in order to disentangle the responses of the emissions to variations of the individual environmental parameters (such as PPFD and temperature) and to diverse abiotic stress factors. Young plants were enclosed in transparent all-Teflon dynamic enclosures (cuvettes) through which BVOC-free and RH-controlled air was sent. BVOC enriched air was subsequently sampled from the plant cuvettes and an empty cuvette (background) and analyzed for BVOCs in a high sensitivity Proton Transfer Reaction Mass Spectrometer (hs-PTR-MS) and for CO2 in a LI-7000 non-dispersive IR gas analyzer. Emissions were monitored at constant temperature (25 °C) and at a stepwise varying PPFD pattern (0-650 µmol m-2 s-1). For maize plants, sudden light/dark transitions at the end of the photoperiod were accompanied by prompt and considerable increases in methanol (m/z 33) and water vapor (m/z 39) emissions. Moreover, guttation droplets appeared on the sides and the tips of the leaves within a few minutes after light/dark transition. Therefore the assumption has been raised that methanol is also coming out with guttation fluid from the leaves. Consequently, guttation fluid was collected from young maize and wheat plants, injected in an empty enclosure and sampled by PTR-MS. Methanol and a large number of other compounds were observed from guttation fluid. Recent studies have shown that guttation from agricultural crops frequently occurs in field conditions. Further research is required to find out the source strength of methanol emissions by this guttation

  20. Hydroxyl (6−2 airglow emission intensity ratios for rotational temperature determination

    Directory of Open Access Journals (Sweden)

    R. P. Lowe

    Full Text Available OH(6–2 Q1/P1 and R1/P1 airglow emission intensity ratios, for rotational states up to j' = 4.5, are measured to be lower than implied by transition probabilities published by various authors including Mies, Langhoff et al. and Turnbull and Lowe. Experimentally determined relative values of j' transitions yield OH(6–2 rotational temperatures 2 K lower than Langhoff et al., 7 K lower than Mies and 13 K lower than Turnbull and Lowe.Key words: Atmospheric composition and structure (airglow and aurora; pressure, density and temperature

  1. Development of net energy ratio and emission factor for quad-generation pathways

    DEFF Research Database (Denmark)

    Rudra, Souman; Rosendahl, Lasse; Kumar, Amit

    2014-01-01

    of this study was to evaluate the energy performance, reduce GHG and acid rain precursor emission, and use of biomass for different outputs based on demand. Finally, a sensitivity analysis and a comparative study ar conducted for expected technological improvements and factors that could increase the energy......, methanol and methane. Circulating fluidized bed gasifier and the gas technology institute (GTI) gasifier technologies are used for this quad-generation process. Two different biomass feedstocks are considered in this study. The net energy ratio for six different pathways having the range of between 1...

  2. Methanol and other VOC fluxes from a Danish beech forest during late springtime

    DEFF Research Database (Denmark)

    Schade, Gunnar W.; Solomon, Sheena J.; Dellwik, Ebba

    2011-01-01

    In-canopy mixing ratio gradients and above-canopy fluxes of several volatile organic compounds (VOCs) were measured using a commercial proton transfer reaction mass spectrometer (PTR-MS) in a European beech (Fagus sylvatica) forest in Denmark. Fluxes of methanol were bidirectional: Emission...

  3. POLYCYCLIC AROMATIC HYDROCARBON AND EMISSION LINE RATIOS IN ACTIVE GALACTIC NUCLEI AND STARBURST GALAXIES

    International Nuclear Information System (INIS)

    Sales, Dinalva A.; Pastoriza, M. G.; Riffel, R.

    2010-01-01

    We study the polycyclic aromatic hydrocarbon (PAH) bands, ionic emission lines, and mid-infrared continuum properties in a sample of 171 emission line galaxies taken from the literature plus 15 new active galactic nucleus (AGN) Spitzer spectra. We normalize the spectra at λ = 23 μm and grouped them according to the type of nuclear activity. The continuum shape steeply rises for longer wavelengths and can be fitted with a warm blackbody distribution of T ∼ 150-300 K. The brightest PAH spectral bands (6.2, 7.7, 8.6, 11.3, and 12.7 μm) and the forbidden emission lines of [Si II] 34.8 μm, [Ar II] 6.9 μm, [S III] 18.7 and 33.4 μm were detected in all the starbursts and in ∼80% of the Seyfert 2. Taking under consideration only the PAH bands at 7.7 μm, 11.3 μm, and 12.7 μm, we find that they are present in ∼80% of the Seyfert 1, while only half of this type of activity show the 6.2 μm and 8.6 μm PAH bands. The observed intensity ratios for neutral and ionized PAHs (6.2 μm/7.7 μm x 11.3 μm/7.7 μm) were compared to theoretical intensity ratios, showing that AGNs have higher ionization fraction and larger PAH molecules (≥180 carbon atoms) than SB galaxies. The ratio between the ionized (7.7 μm) and the neutral PAH bands (8.6 μm and 11.3 μm) are distributed over different ranges for AGNs and SB galaxies, suggesting that these ratios could depend on the ionization fraction, as well as on the hardness of the radiation field. The ratio between the 7.7 μm and 11.3 μm bands is nearly constant with the increase of [Ne III]15.5 μm/[Ne II] 12.8 μm, indicating that the fraction of ionized to neutral PAH bands does not depend on the hardness of the radiation field. The equivalent width of both PAH features show the same dependence (strongly decreasing) with [Ne III]/[Ne II], suggesting that the PAH molecules, emitting either ionized (7.7 μm) or neutral (11.3 μm) bands, may be destroyed with the increase of the hardness of the radiation field.

  4. Chemistry of Volatile Organic Compounds in the Los Angeles basin: Nighttime Removal of Alkenes and Determination of Emission Ratios

    Science.gov (United States)

    de Gouw, J. A.; Gilman, J. B.; Kim, S.-W.; Lerner, B. M.; Isaacman-VanWertz, G.; McDonald, B. C.; Warneke, C.; Kuster, W. C.; Lefer, B. L.; Griffith, S. M.; Dusanter, S.; Stevens, P. S.; Stutz, J.

    2017-11-01

    We reanalyze a data set of hydrocarbons in ambient air obtained by gas chromatography-mass spectrometry at a surface site in Pasadena in the Los Angeles basin during the NOAA California Nexus study in 2010. The number of hydrocarbon compounds quantified from the chromatograms is expanded through the use of new peak-fitting data analysis software. We also reexamine hydrocarbon removal processes. For alkanes, small alkenes, and aromatics, the removal is determined by the reaction with hydroxyl (OH) radicals. For several highly reactive alkenes, the nighttime removal by ozone and nitrate (NO3) radicals is also significant. We discuss how this nighttime removal affects the determination of emission ratios versus carbon monoxide (CO) and show that previous estimates based on nighttime correlations with CO were too low. We analyze model output from the Weather Research and Forecasting-Chemistry model for hydrocarbons and radicals at the Pasadena location to evaluate our methods for determining emission ratios from the measurements. We find that our methods agree with the modeled emission ratios for the domain centered on Pasadena and that the modeled emission ratios vary by 23% across the wider South Coast basin. We compare the alkene emission ratios with published results from ambient measurements and from tunnel and dynamometer studies of motor vehicle emissions. We find that with few exceptions the composition of alkene emissions determined from the measurements in Pasadena closely resembles that of motor vehicle emissions.

  5. Comparison of wintertime CO to NOx ratios to MOVES and MOBILE6.2 on-road emissions inventories

    Science.gov (United States)

    Wallace, H. W.; Jobson, B. T.; Erickson, M. H.; McCoskey, J. K.; VanReken, T. M.; Lamb, B. K.; Vaughan, J. K.; Hardy, R. J.; Cole, J. L.; Strachan, S. M.; Zhang, W.

    2012-12-01

    The CO-to-NOx molar emission ratios from the US EPA vehicle emissions models MOVES and MOBILE6.2 were compared to urban wintertime measurements of CO and NOx. Measurements of CO, NOx, and volatile organic compounds were made at a regional air monitoring site in Boise, Idaho for 2 months from December 2008 to January 2009. The site is impacted by roadway emissions from a nearby busy urban arterial roads and highway. The measured CO-to-NOx ratio for morning rush hour periods was 4.2 ± 0.6. The average CO-to-NOx ratio during weekdays between the hours of 08:00 and 18:00 when vehicle miles travelled were highest was 5.2 ± 0.5. For this time period, MOVES yields an average hourly CO-to-NOx ratio of 9.1 compared to 20.2 for MOBILE6.2. Off-network emissions are a significant fraction of the CO and NOx emissions in MOVES, accounting for 65% of total CO emissions, and significantly increase the CO-to-NOx molar ratio. Observed ratios were more similar to the average hourly running emissions for urban roads determined by MOVES to be 4.3.

  6. Influence of Compression Ratio on the Performance and Emission Characteristics of Annona Methyl Ester Operated DI Diesel Engine

    Directory of Open Access Journals (Sweden)

    Senthil Ramalingam

    2014-09-01

    Full Text Available This study aims to find the optimum performance and emission characteristics of single cylinder variable compression ratio (VCR engine with different blends of Annona methyl ester (AME as fuel. The performance parameters such as specific fuel consumption (SFC, brake thermal efficiency (BTE, and emission levels of HC, CO, Smoke, and NOx were compared with the diesel fuel. It is found that, at compression ratio of 17: 1 for A20 blended fuel (20% AME + 80% Diesel shows better performance and lower emission level which is very close to neat diesel fuel. The engine was operated with different values of compression ratio (15, 16, and 17 to find out best possible combination for operating engine with blends of AME. It is also found that the increase of compression ratio increases the BTE and reduces SFC and has lower emission without any engine in design modifications.

  7. CO2 emissions embodied in China-US trade: Input-output analysis based on the emergy/dollar ratio

    International Nuclear Information System (INIS)

    Du Huibin; Guo Jianghong; Mao Guozhu; Smith, Alexander M.; Wang Xuxu; Wang, Yuan

    2011-01-01

    To gain insight into changes in CO 2 emissions embodied in China-US trade, an input-output analysis based on the emergy/dollar ratio (EDR) is used to estimate embodied CO 2 emissions; a structural decomposition analysis (SDA) is employed to analyze the driving factors for changes in CO 2 emissions embodied in China's exports to the US during 2002-2007. The results of the input-output analysis show that net export of CO 2 emissions increased quickly from 2002 to 2005 but decreased from 2005 to 2007. These trends are due to a reduction in total CO 2 emission intensity, a decrease in the exchange rate, and small imports of embodied CO 2 emissions. The results of the SDA demonstrate that total export volume was the largest driving factor for the increase in embodied CO 2 emissions during 2002-2007, followed by intermediate input structure. Direct CO 2 emissions intensity had a negative effect on changes in embodied CO 2 emissions. The results suggest that China should establish a framework for allocating emission responsibilities, enhance energy efficiency, and improve intermediate input structure. - Highlights: → An input-output analysis based on the emergy/dollar ratio estimated embodied CO 2 . → A structural decomposition analysis analyzed the driving factors. → Net export of CO 2 increased from 2002 to 2005 but decreased from 2005 to 2007. → Total export volume was the largest driving factor. → A framework for allocating emission responsibilities.

  8. EFFECT OF COMPRESSION RATIO ON ENERGY AND EMISSION OF VCR DIESEL ENGINE FUELLED WITH DUAL BLENDS OF BIODIESEL

    Directory of Open Access Journals (Sweden)

    R. D. EKNATH

    2014-10-01

    Full Text Available In recent 10 years biodiesel fuel was studied extensively as an alternative fuel. Most of researchers reported performance and emission of biodiesel and their blends with constant compression ratio. Also all the research was conducted with use of single biodiesel and its blend. Few reports are observed with the use of variable compression ratio and blends of more than one biodiesel. Main aim of the present study is to analyse the effect of compression ratio on the performance and emission of dual blends of biodiesel. In the present study Blends of Jatropha and Karanja with Diesel fuel was tested on single cylinder VCR DI diesel engine for compression ratio 16 and 18. High density of biodiesel fuel causes longer delay period for Jatropha fuel was observed compare with Karanja fuel. However blending of two biodiesel K20J40D results in to low mean gas temperature which is the main reason for low NOx emission.

  9. Galaxy emission line classification using three-dimensional line ratio diagrams

    Energy Technology Data Exchange (ETDEWEB)

    Vogt, Frédéric P. A.; Dopita, Michael A.; Kewley, Lisa J.; Sutherland, Ralph S. [Research School of Astronomy and Astrophysics, Australian National University, Canberra, ACT 2611 (Australia); Scharwächter, Julia [Observatoire de Paris, LERMA (CNRS: UMR8112), 61 Av. de l' Observatoire, F-75014 Paris (France); Basurah, Hassan M.; Ali, Alaa; Amer, Morsi A., E-mail: frederic.vogt@anu.edu.au [Astronomy Department, King Abdulaziz University, P.O. Box 80203, Jeddah (Saudi Arabia)

    2014-10-01

    Two-dimensional (2D) line ratio diagnostic diagrams have become a key tool in understanding the excitation mechanisms of galaxies. The curves used to separate the different regions—H II-like or excited by an active galactic nucleus (AGN)—have been refined over time but the core technique has not evolved significantly. However, the classification of galaxies based on their emission line ratios really is a multi-dimensional problem. Here we exploit recent software developments to explore the potential of three-dimensional (3D) line ratio diagnostic diagrams. We introduce the ZQE diagrams, which are a specific set of 3D diagrams that separate the oxygen abundance and the ionization parameter of H II region-like spectra and also enable us to probe the excitation mechanism of the gas. By examining these new 3D spaces interactively, we define the ZE diagnostics, a new set of 2D diagnostics that can provide the metallicity of objects excited by hot young stars and that cleanly separate H II region-like objects from the different classes of AGNs. We show that these ZE diagnostics are consistent with the key log [N II]/Hα versus log [O III]/Hβ diagnostic currently used by the community. They also have the advantage of attaching a probability that a given object belongs to one class or the other. Finally, we discuss briefly why ZQE diagrams can provide a new way to differentiate and study the different classes of AGNs in anticipation of a dedicated follow-up study.

  10. Effect of compression ratio, equivalence ratio and engine speed on the performance and emission characteristics of a spark ignition engine using hydrogen as a fuel

    Energy Technology Data Exchange (ETDEWEB)

    Sadiq Al-Baghdadi, M.A.R. [University of Babylon (Iraq). Dept. of Mechanical Engineering

    2004-12-01

    The present energy situation has stimulated active research interest in non-petroleum and non-polluting fuels, particularly for transportation, power generation, and agricultural sectors. Researchers have found that hydrogen presents the best and an unprecedented solution to the energy crises and pollution problems, due to its superior combustion qualities and availability. This paper discusses analytically and provides data on the effect of compression ratio, equivalence ratio and engine speed on the engine performance, emissions and pre-ignition limits of a spark ignition engine operating on hydrogen fuel. These data are important in order to understand the interaction between engine performance and emission parameters, which will help engine designers when designing for hydrogen. (author)

  11. A comparison of new measurements of total monoterpene flux with improved measurements of speciated monoterpene flux

    Directory of Open Access Journals (Sweden)

    A. Lee

    2005-01-01

    Full Text Available Many monoterpenes have been identified in forest emissions using gas chromatography (GC. Until now, it has been impossible to determine whether all monoterpenes are appropriately measured using GC techniques. We used a proton transfer reaction mass spectrometer (PTR-MS coupled with the eddy covariance (EC technique to measure mixing ratios and fluxes of total monoterpenes above a ponderosa pine plantation. We compared PTR-MS-EC results with simultaneous measurements of eight speciated monoterpenes, β-pinene, α-pinene, 3-carene, d-limonene, β-phellandrene, α-terpinene, camphene, and terpinolene, made with an automated, in situ gas chromatograph with flame ionization detectors (GC-FID, coupled to a relaxed eddy accumulation system (REA. Monoterpene mixing ratios and fluxes measured by PTR-MS averaged 30±2.3% and 31±9.2% larger than by GC-FID, with larger mixing ratio discrepancies between the two techniques at night than during the day. Two unidentified peaks that correlated with β-pinene were resolved in the chromatograms and completely accounted for the daytime difference and reduced the nighttime mixing ratio difference to 20±2.9%. Measurements of total monoterpenes by PTR-MS-EC indicated that GC-FID-REA measured the common, longer-lived monoterpenes well, but that additional terpenes were emitted from the ecosystem that represented an important contribution to the total mixing ratio above the forest at night.

  12. Similarity ratio analysis for early stage fault detection with optical emission spectrometer in plasma etching process.

    Directory of Open Access Journals (Sweden)

    Jie Yang

    Full Text Available A Similarity Ratio Analysis (SRA method is proposed for early-stage Fault Detection (FD in plasma etching processes using real-time Optical Emission Spectrometer (OES data as input. The SRA method can help to realise a highly precise control system by detecting abnormal etch-rate faults in real-time during an etching process. The method processes spectrum scans at successive time points and uses a windowing mechanism over the time series to alleviate problems with timing uncertainties due to process shift from one process run to another. A SRA library is first built to capture features of a healthy etching process. By comparing with the SRA library, a Similarity Ratio (SR statistic is then calculated for each spectrum scan as the monitored process progresses. A fault detection mechanism, named 3-Warning-1-Alarm (3W1A, takes the SR values as inputs and triggers a system alarm when certain conditions are satisfied. This design reduces the chance of false alarm, and provides a reliable fault reporting service. The SRA method is demonstrated on a real semiconductor manufacturing dataset. The effectiveness of SRA-based fault detection is evaluated using a time-series SR test and also using a post-process SR test. The time-series SR provides an early-stage fault detection service, so less energy and materials will be wasted by faulty processing. The post-process SR provides a fault detection service with higher reliability than the time-series SR, but with fault testing conducted only after each process run completes.

  13. Estimation of Fine and Oversize Particle Ratio in a Heterogeneous Compound with Acoustic Emissions

    Directory of Open Access Journals (Sweden)

    Ejay Nsugbe

    2018-03-01

    Full Text Available The final phase of powder production typically involves a mixing process where all of the particles are combined and agglomerated with a binder to form a single compound. The traditional means of inspecting the physical properties of the final product involves an inspection of the particle sizes using an offline sieving and weighing process. The main downside of this technique, in addition to being an offline-only measurement procedure, is its inability to characterise large agglomerates of powders due to sieve blockage. This work assesses the feasibility of a real-time monitoring approach using a benchtop test rig and a prototype acoustic-based measurement approach to provide information that can be correlated to product quality and provide the opportunity for future process optimisation. Acoustic emission (AE was chosen as the sensing method due to its low cost, simple setup process, and ease of implementation. The performance of the proposed method was assessed in a series of experiments where the offline quality check results were compared to the AE-based real-time estimations using data acquired from a benchtop powder free flow rig. A designed time domain based signal processing method was used to extract particle size information from the acquired AE signal and the results show that this technique is capable of estimating the required ratio in the washing powder compound with an average absolute error of 6%.

  14. Effect of C/N ratio, aeration rate and moisture content on ammonia and greenhouse gas emission during the composting.

    Science.gov (United States)

    Jiang, Tao; Schuchardt, Frank; Li, Guoxue; Guo, Rui; Zhao, Yuanqiu

    2011-01-01

    Gaseous emission (N2O, CH4 and NH3) from composting can be an important source of anthropogenic greenhouse gas and air pollution. A laboratory scale orthogonal experiment was conducted to estimate the effects of C/N ratio, aeration rate and initial moisture content on gaseous emission during the composting of pig faeces from Chinese Ganqinfen system. The results showed that about 23.9% to 45.6% of total organic carbon (TOC) was lost in the form of CO2 and 0.8% to 7.5% of TOC emitted as CH4. Most of the nitrogen was lost in the form of NH3, which account for 9.6% to 32.4% of initial nitrogen. N2O was also an important way of nitrogen losses and 1.5% to 7.3% of initial total nitrogen was lost as it. Statistic analysis showed that the aeration rate is the most important factor which could affect the NH3 (p = 0.0189), CH4 (p = 0.0113) and N2O (p = 0.0493) emissions significantly. Higher aeration rates reduce the CH4 emission but increase the NH3 and N2O losses. C/N ratio could affect the NH3 (p = 0.0442) and CH4 (p = 0.0246) emissions significantly, but not the N2O. Lower C/N ratio caused higher NH3 and CH4 emissions. The initial moisture content can not influence the gaseous emission significantly. Most treatments were matured after 37 days, except a trial with high moisture content and a low C/N ratio.

  15. Performance and exhaust emission characteristics of variable compression ratio diesel engine fuelled with esters of crude rice bran oil.

    Science.gov (United States)

    Vasudeva, Mohit; Sharma, Sumeet; Mohapatra, S K; Kundu, Krishnendu

    2016-01-01

    As a substitute to petroleum-derived diesel, biodiesel has high potential as a renewable and environment friendly energy source. For petroleum importing countries the choice of feedstock for biodiesel production within the geographical region is a major influential factor. Crude rice bran oil is found to be good and viable feedstock for biodiesel production. A two step esterification is carried out for higher free fatty acid crude rice bran oil. Blends of 10, 20 and 40 % by vol. crude rice bran biodiesel are tested in a variable compression ratio diesel engine at compression ratio 15, 16, 17 and 18. Engine performance and exhaust emission parameters are examined. Cylinder pressure-crank angle variation is also plotted. The increase in compression ratio from 15 to 18 resulted in 18.6 % decrease in brake specific fuel consumption and 14.66 % increase in brake thermal efficiency on an average. Cylinder pressure increases by 15 % when compression ratio is increased. Carbon monoxide emission decreased by 22.27 %, hydrocarbon decreased by 38.4 %, carbon dioxide increased by 17.43 % and oxides of nitrogen as NOx emission increased by 22.76 % on an average when compression ratio is increased from 15 to 18. The blends of crude rice bran biodiesel show better results than diesel with increase in compression ratio.

  16. Regulation of Floral Terpenoid Emission and Biosynthesis in Sweet Basil (Ocimum basilicum).

    Science.gov (United States)

    Jiang, Yifan; Ye, Jiayan; Li, Shuai; Niinemets, Ülo

    2016-12-01

    Past studies have focused on the composition of essential oil of Ocimum basilicum leaves, but data on composition and regulation of its aerial emissions, especially floral volatile emissions are scarce. We studied the chemical profile, within-flower spatial distribution (sepals, petals, pistils with stamina and pedicels), diurnal emission kinetics and effects of exogenous methyl jasmonate (MeJA) application on the emission of floral volatiles by dynamic headspace collection and identification using gas chromatography-mass spectrometry (GC-MS) and proton transfer reaction mass spectrometry (PTR-MS). We observed more abundant floral emissions from flowers compared with leaves. Sepals were the main emitters of floral volatiles among the flower parts studied. The emissions of lipoxygenase compounds (LOX) and monoterpenoids, but not sesquiterpene emissions, displayed a diurnal variation driven by light. Response to exogenous MeJA treatment of flowers consisted of a rapid stress response and a longer-term acclimation response. The initial response was associated with enhanced emissions of fatty acid derivatives, monoterpenoids, and sesquiterpenoids without variation of the composition of individual compounds. The longer-term response was associated with enhanced monoterpenoid and sesquiterpenoid emissions with profound changes in the emission spectrum. According to correlated patterns of terpenoid emission changes upon stress, highlighted by a hierarchical cluster analysis, candidate terpenoid synthases responsible for observed diversity and complexity of released terpenoid blends were postulated. We conclude that flower volatile emissions differ quantitatively and qualitatively from leaf emissions, and overall contribute importantly to O. basilicum flavor, especially under stress conditions.

  17. Regulation of Floral Terpenoid Emission and Biosynthesis in Sweet Basil (Ocimum basilicum)

    Science.gov (United States)

    Jiang, Yifan; Ye, Jiayan; Li, Shuai; Niinemets, Ülo

    2018-01-01

    Past studies have focused on the composition of essential oil of Ocimum basilicum leaves, but data on composition and regulation of its aerial emissions, especially floral volatile emissions are scarce. We studied the chemical profile, within-flower spatial distribution (sepals, petals, pistils with stamina and pedicels), diurnal emission kinetics and effects of exogenous methyl jasmonate (MeJA) application on the emission of floral volatiles by dynamic headspace collection and identification using gas chromatography-mass spectrometry (GC-MS) and proton transfer reaction mass spectrometry (PTR-MS). We observed more abundant floral emissions from flowers compared with leaves. Sepals were the main emitters of floral volatiles among the flower parts studied. The emissions of lipoxygenase compounds (LOX) and monoterpenoids, but not sesquiterpene emissions, displayed a diurnal variation driven by light. Response to exogenous MeJA treatment of flowers consisted of a rapid stress response and a longer-term acclimation response. The initial response was associated with enhanced emissions of fatty acid derivatives, monoterpenoids, and sesquiterpenoids without variation of the composition of individual compounds. The longer-term response was associated with enhanced monoterpenoid and sesquiterpenoid emissions with profound changes in the emission spectrum. According to correlated patterns of terpenoid emission changes upon stress, highlighted by a hierarchical cluster analysis, candidate terpenoid synthases responsible for observed diversity and complexity of released terpenoid blends were postulated. We conclude that flower volatile emissions differ quantitatively and qualitatively from leaf emissions, and overall contribute importantly to O. basilicum flavor, especially under stress conditions. PMID:29367803

  18. Defect controlled tuning of the ratio of ultraviolet to visible light emission in TiO2 thin films

    International Nuclear Information System (INIS)

    Mondal, S.; Basak, D.

    2016-01-01

    The photoluminescence (PL) of sol–gel TiO 2 thin film has been found to be largely dependent on the post-deposition processing such as annealing at 500 °C in air, vacuum and ultraviolet (UV) light curing at room temperature. A detailed analysis of room temperature PL spectra shows that the UV/VIS PL peak intensity ratio is maximum for the film which has been annealed at 500 °C in air. X-ray photoelectron spectroscopy confirms the presence of Ti 3+ type of point defects. The visible emission is deconvoluted to green and orange emissions. Analyses of the present experimental results indicate that V O and/or Ti 3+ causes the green emission and OH and/or excess O 2 adsorption on TiO 2 surface probably causes the orange emission. The time correlated single photon counting spectroscopy data of the UV PL indicates higher number defects in vacuum annealed and UV cured films as compared to the air annealed film. Correlation of the results altogether allows us to conclude that the surface defects those causing the visible emission are smaller in number in the air annealed film. The present results may be useful for tuning the relative PL intensities of UV, green and orange emissions. - Highlights: • Sol–gel TiO 2 films were treated both in air, vacuum at 500 °C and under UV light (room temperature). • UV/VIS PL intensity ratio is maximum for air annealed and minimum for UV cured films. • Both green and orange emission predominantly controls the visible emission of TiO 2 . • The visible emission exhibit a clear correlation with Ti 3+  defects on the surface.

  19. Estimate of anthropogenic halocarbon emission based on measured ratio relative to CO in the Pearl River Delta region, China

    Directory of Open Access Journals (Sweden)

    M. Shao

    2011-05-01

    Full Text Available Using a GC/FID/MS system, we analyzed the mixing ratio of 16 halocarbon species in more than 100 air samples collected in 2004 from the Pearl River Delta (PRD region of southern China. The results revealed that there are elevated mixing ratios for most of halocarbons, especially for HClC = CCl2 (trichloroethylene, TCE, CH2Cl2 (dichloromethane, DCM, CH3 Br (bromomethane, HCFC-22, CHCl3 (trichloromethane, CCl4 (tetrachloromethane, Cl2C = CCl2 (perchloroethylene, PCE, CH3CCl3 (methyl chloroform, MCF, and CFC-12. Comparisons were done with the data from TRACE-P and ALE/GAGE/AGAGE experiments, we found that the large variability in mixing ratios (relative standard deviation ranged from 9.31 % to 96.55 % of the halocarbons suggested substantial local emissions from the PRD region in 2004. Correlations between the mixing ratio of each species and carbon monoxide (CO was examined, and then the emission of each halocarbon was quantified based on scaling the optimized CO emission inventory with the slope of the regression line fitted to each species relative to CO. The calculated results revealed that mass of CH2Cl2 (7.0 Gg, CH3CCl3 (6.7 Gg, and Cl2C = CCl2 (2.3 Gg accounted for about 62.9 % of total halocarbon emissions, it suggested a significant contribution from solvent use in the PRD region. Emissions of HCFC-22 (3.5 Gg, an alternative refrigerant to chlorofluorocarbons (CFCs, were about 2.3 times greater than those of CFC-12 (1.6 Gg. CFC-12 and HCFC-22 accounted for 21.5 % of total emissions of halocarbons, so that the refrigerant would be the second largest source of halocarbons. However, the ratio approach found only minor emissions of CFCs, such as CFC-11, and the emission of CFC-114 and CFC-113 were close to zero. Emissions of other anthropogenic halocarbons, such as CCl

  20. Emission Ratios for Ammonia and Formic Acid and Observations of Peroxy Acetyl Nitrate (PAN and Ethylene in Biomass Burning Smoke as Seen by the Tropospheric Emission Spectrometer (TES

    Directory of Open Access Journals (Sweden)

    Vivienne H. Payne

    2011-11-01

    Full Text Available We use the Tropospheric Emission Spectrometer (TES aboard the NASA Aura satellite to determine the concentrations of the trace gases ammonia (NH3 and formic acid (HCOOH within boreal biomass burning plumes, and present the first detection of peroxy acetyl nitrate (PAN and ethylene (C2H4 by TES. We focus on two fresh Canadian plumes observed by TES in the summer of 2008 as part of the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS-B campaign. We use TES retrievals of NH3 and HCOOH within the smoke plumes to calculate their emission ratios (1.0% ± 0.5% and 0.31% ± 0.21%, respectively relative to CO for these Canadian fires. The TES derived emission ratios for these gases agree well with previous aircraft and satellite estimates, and can complement ground-based studies that have greater surface sensitivity. We find that TES observes PAN mixing ratios of ~2 ppb within these mid-tropospheric boreal biomass burning plumes when the average cloud optical depth is low ( < 0.1 and that TES can detect C2H4 mixing ratios of ~2 ppb in fresh biomass burning smoke plumes.

  1. OVOC Emissions and Atmospheric Transformations.

    Science.gov (United States)

    Yokelson, R. J.; Christian, T. J.; Bertschi, I. T.; Ward, D. E.; Field, R. J.; Hobbs, P. V.; Goode, J.; Mason, S.; Susott, R.; Babbitt, R.; Hao, W. M.

    2002-12-01

    We quantified the main emissions from a few vegetation samples and many biomass fires using ground-based, open-path FTIR and airborne, closed-cell FTIR. The two instruments have been rigorously compared to each other and to PTR-MS and canister sampling. OVOC are major emissions from plants. OVOC account for about 70 percent of NMOC from savanna fires (the largest type of biomass burning) and 70-80 percent of NMOC from production and use of domestic biofuels (the second largest type of biomass burning). A table of average biofuel emissions is presented. Data from laboratory and free-burning fires, obtained from Alaska to South Africa, is used to develop equations that predict OVOC emissions from a wide variety of global fires. The impact of OVOC on smoke plume chemistry and the post-emission transformations of OVOC were investigated with two models. Addition of HCHO alone to the simple chemistry used in some global models dramatically reduces NOx lifetime and speeds up O3 formation rates in plumes. A detailed model verifies these effects and shows that OVOC profoundly affect formation of HOx, peroxide, and nitrogen reservoir species. The modeled photochemical transformations of OVOC are diverse, but some key pathways are unknown. We observed rapid production of both O3 and additional OVOC and OH of 1.7E7 in smoke plumes in Alaska and Africa; all reasonably consistent with model predictions. In addition, we found that cloud processing caused large post-emission changes in smoke trace gases including removal of nearly all methanol, a decrease in acetic acid, and a large increase in HCHO. These observations suggest that OVOC could react in cloud droplets and lead to production of modified aerosol. In addition, transport of OVOC by deep convection may be associated with large effects not explained by solubility alone.

  2. Gas Phase Emission Ratios From In-Use Diesel and CNG Curbside Passenger Buses in New York City

    Science.gov (United States)

    Herndon, S. C.; Shorter, J.; Canagaratna, M.; Jayne, J.; Nelson, D. D.; Wormhoudt, J. C.; Williams, P.; Silva, P. J.; Shi, Q.; Ghertner, A.; Zahniser, M.; Worsnop, D.; Kolb, C.; Lanni, T.; Drewnick, F.; Demerjian, K. L.

    2002-12-01

    The Aerodyne Mobile Laboratory simultaneously measured gas phase and particulate emissions from in use vehicles during two campaigns in New York City. The campaigns took place during two weeks in October, 2000 and four weeks in July-August, 2001. Passenger curbside buses were the primary focus of the study, but school buses and several other heavy duty diesel vehicles were also characterized. This paper describes the methodologies used to measure individual in use vehicles and presents the results of the gas phase measurements. Emission ratios for NO, NO2, SO2, N2O, CO, CH4 and H2CO relative to CO2 have been determined across several classes of buses. The gas phase concentrations were measured each second, using Tunable Infrared Laser Direct Absorption Spectroscopy (TILDAS). Some of the categories of buses into which the data has been sorted are; diesel (both 6V92 and Series 50) with and without the Continuous Regenerative Technology (CRT) retrofit, compressed natural gas powered(CNG) and hybrid diesel-electric buses. The New York Metropolitan Transit Authority (MTA) cooperated with this work, providing details about each of their buses followed. In addition to MTA buses, other New York City passenger bus operators were also measured. In September 2000, MTA began to switch to 30 ppm sulfur diesel fuel while it is believed the non MTA operators did not. The measured emission ratios show that low sulfur fuel greatly reduces the amount of SO2 per CO2. Roughly one third of the MTA fleet of diesel buses have been equipped with the CRT retrofit. The gas phase results of interest in this category show increased direct emission of NO2 and companion work (also submitted to the 12th CRC) show the impact the CRT refit has on particulate emissions. CNG buses show increased H2CO and CH4 emission ratios relative to diesel powered motors.

  3. 129I/127I ratios in Scottish coastal surface sea water: Geographical and temporal responses to changing emissions

    International Nuclear Information System (INIS)

    Schnabel, Christoph; Olive, Valerie; Atarashi-Andoh, Mariko; Dougans, Andrew; Ellam, Robert M.; Freeman, Stewart; Maden, Colin; Stocker, Martin; Synal, Hans-Arno; Wacker, Lukas; Xu Sheng

    2007-01-01

    This work constitutes the first survey of I isotope ratios for Scottish sea water including the first data for the west of Scotland. These data are of importance because of the proximity to the world's second largest emission source of 129 I to the sea, the Sellafield nuclear reprocessing plant, because of the increasing importance of the sea to land transfer of 129 I and also as input data for dose estimates based on this pathway of 129 I. 129 I/ 127 I ratios in SW Scotland reached 3 x 10 -6 in 2004. No strong variation of I isotope ratios was found from 2003 to 2005 in Scottish sea waters. Iodine isotope ratios increased by about a factor of 6 from 1992 to 2003 in NE Scotland, in agreement with the increase of liquid 129 I emissions from Sellafield over that time period. It is demonstrated that 129 I/ 127 I ratios agree better than 129 I concentrations for samples from similar locations taken in very close temporal proximity, indicating that this ratio is more appropriate to interpret than the radionuclide concentration

  4. Combining tracer flux ratio methodology with low-flying aircraft measurements to estimate dairy farm CH4 emissions

    Science.gov (United States)

    Daube, C.; Conley, S.; Faloona, I. C.; Yacovitch, T. I.; Roscioli, J. R.; Morris, M.; Curry, J.; Arndt, C.; Herndon, S. C.

    2017-12-01

    Livestock activity, enteric fermentation of feed and anaerobic digestion of waste, contributes significantly to the methane budget of the United States (EPA, 2016). Studies question the reported magnitude of these methane sources (Miller et. al., 2013), calling for more detailed research of agricultural animals (Hristov, 2014). Tracer flux ratio is an attractive experimental method to bring to this problem because it does not rely on estimates of atmospheric dispersion. Collection of data occurred during one week at two dairy farms in central California (June, 2016). Each farm varied in size, layout, head count, and general operation. The tracer flux ratio method involves releasing ethane on-site with a known flow rate to serve as a tracer gas. Downwind mixed enhancements in ethane (from the tracer) and methane (from the dairy) were measured, and their ratio used to infer the unknown methane emission rate from the farm. An instrumented van drove transects downwind of each farm on public roads while tracer gases were released on-site, employing the tracer flux ratio methodology to assess simultaneous methane and tracer gas plumes. Flying circles around each farm, a small instrumented aircraft made measurements to perform a mass balance evaluation of methane gas. In the course of these two different methane quantification techniques, we were able to validate yet a third method: tracer flux ratio measured via aircraft. Ground-based tracer release rates were applied to the aircraft-observed methane-to-ethane ratios, yielding whole-site methane emission rates. Never before has the tracer flux ratio method been executed with aircraft measurements. Estimates from this new application closely resemble results from the standard ground-based technique to within their respective uncertainties. Incorporating this new dimension to the tracer flux ratio methodology provides additional context for local plume dynamics and validation of both ground and flight-based data.

  5. Combustion and Emission Characteristics of Variable Compression Ignition Engine Fueled with Jatropha curcas Ethyl Ester Blends at Different Compression Ratio

    Directory of Open Access Journals (Sweden)

    Rajneesh Kumar

    2014-01-01

    Full Text Available Engine performance and emission characteristics of unmodified biodiesel fueled diesel engines are highly influenced by their ignition and combustion behavior. In this study, emission and combustion characteristics were studied when the engine operated using the different blends (B10, B20, B30, and B40 and normal diesel fuel (B0 as well as when varying the compression ratio from 16.5 : 1 to 17.5 : 1 to 18.5 : 1. The change of compression ratio from 16.5 : 1 to 18.5 : 1 resulted in 27.1%, 27.29%, 26.38%, 28.48%, and 34.68% increase in cylinder pressure for the blends B0, B10, B20, B30, and B40, respectively, at 75% of rated load conditions. Higher peak heat release rate increased by 23.19%, 14.03%, 26.32%, 21.87%, and 25.53% for the blends B0, B10, B20, B30, and B40, respectively, at 75% of rated load conditions, when compression ratio was increased from16.5 : 1 to 18.5 : 1. The delay period decreased by 21.26%, CO emission reduced by 14.28%, and NOx emission increased by 22.84% for B40 blends at 75% of rated load conditions, when compression ratio was increased from 16.5 : 1 to 18.5 : 1. It is concluded that Jatropha oil ester can be used as fuel in diesel engine by blending it with diesel fuel.

  6. Natural gas facility methane emissions: measurements by tracer flux ratio in two US natural gas producing basins

    Directory of Open Access Journals (Sweden)

    Tara I. Yacovitch

    2017-11-01

    Full Text Available Methane (CH4 emission rates from a sample of natural gas facilities across industry sectors were quantified using the dual tracer flux ratio methodology. Measurements were conducted in study areas within the Fayetteville shale play, Arkansas (FV, Sept–Oct 2015, 53 facilities, and the Denver-Julesburg basin, Colorado, (DJ, Nov 2014, 21 facilities. Distributions of methane emission rates at facilities by type are computed and statistically compared with results that cover broader geographic regions in the US (Allen et al., 2013, Mitchell et al., 2015. DJ gathering station emission rates (kg CH4 hr–1 are lower, while FV gathering and production sites are statistically indistinguishable as compared to these multi-basin results. However, FV gathering station throughput-normalized emissions are statistically lower than multi-basin results (0.19% vs. 0.44%. This implies that the FV gathering sector is emitting less per unit of gas throughput than would be expected from the multi-basin distribution alone. The most common emission rate (i.e. mode of the distribution for facilities in this study is 40 kg CH4 hr–1 for FV gathering stations, 1.0 kg CH4 hr–1 for FV production pads, and 11 kg CH4 hr–1 for DJ gathering stations. The importance of study design is discussed, including the benefits of site access and data sharing with industry and of a scientist dedicated to measurement coordination and site choice under evolving wind conditions.

  7. FeII/MgII Emission Line Ratio in High Redshift Quasars

    DEFF Research Database (Denmark)

    Dietrich, M.; Hamann, F.; Appenzeller, I.

    2003-01-01

    the evolution of the FeII/MgII ratio over a wider range in cosmic time, we measured this ratio for composite quasar spectra which cover a redshift range of 0 4 quasars must have started already at an epoch corresponding to z_f = 6 to 9, when the age of the universe was ~0.5 Gyr (H_o = 72 km/s/Mpc, Omega_M = 0...

  8. Effect of compression ratio on performance, combustion and emission characteristics of a dual fuel diesel engine run on raw biogas

    International Nuclear Information System (INIS)

    Bora, Bhaskor J.; Saha, Ujjwal K.; Chatterjee, Soumya; Veer, Vijay

    2014-01-01

    Highlights: • Maximum brake thermal efficiency of 20.04% was obtained in dual fuel mode. • Compression ratio of 18 produced the maximum brake thermal efficiency. • Maximum replacement of diesel was found to be 79.46% at a compression ratio of 18. • CO gets reduced by 26.22% with the increase of compression ratio from 16 to18. • HC gets reduced by 41.97% with the increase of compression ratio from 16 to18. - Abstract: The energy consumption of the world is increasing at a staggering rate due to population explosion. The extensive use of energy has led to fossil fuel depletion and the rise in pollution. Renewable energy holds the key solution to these aforementioned problems. Biogas, one such renewable fuel, can be used in a diesel engine under dual fuel mode for the generation of power. This work attempts to unfold the effect of compression ratio on the performance, combustion and emission characteristics of a dual fuel diesel engine run on raw biogas. For this investigation, a 3.5 kW single cylinder, direct injection, water cooled, variable compression ratio diesel engine is converted into a biogas run dual fuel diesel engine by connecting a venturi gas mixer at the inlet manifold. Experiments have been conducted at various compression ratios (18, 17.5, 17 and 16) and under different loading conditions fixing the standard injection timing at 23° before top dead centre. At 100% load, the brake thermal efficiencies of the dual fuel mode are found to be 20.04%, 18.25%, 17.07% and 16.42% at compression ratios of 18, 17.5, 17 and 16, respectively, whereas at the same load, the diesel mode shows an efficiency of 27.76% at a compression ratio of 17.5. The maximum replacement of the precious fossil fuel is found to be 79.46%, 76.1%, 74% and 72% at compression ratios of 18, 17.5, 17 and 16, respectively at 100% load. For the dual fuel mode, on an average, there is a reduction in carbon monoxide as well as hydrocarbon emission by 26.22% and 41.97% when compression

  9. Performance and emission of generator Diesel engine using methyl esters of palm oil and diesel blends at different compression ratio

    Science.gov (United States)

    Aldhaidhawi, M.; Chiriac, R.; Bădescu, V.; Pop, H.; Apostol, V.; Dobrovicescu, A.; Prisecaru, M.; Alfaryjat, A. A.; Ghilvacs, M.; Alexandru, A.

    2016-08-01

    This study proposes engine model to predicate the performance and exhaust gas emissions of a single cylinder four stroke direct injection engine which was fuelled with diesel and palm oil methyl ester of B7 (blends 7% palm oil methyl ester with 93% diesel by volume) and B10. The experiment was conducted at constant engine speed of 3000 rpm and different engine loads operations with compression ratios of 18:1, 20:1 and 22:1. The influence of the compression ratio and fuel typeson specific fuel consumption and brake thermal efficiency has been investigated and presented. The optimum compression ratio which yields better performance has been identified. The result from the present work confirms that biodiesel resulting from palm oil methyl ester could represent a superior alternative to diesel fuel when the engine operates with variable compression ratios. The blends, when used as fuel, result in a reduction of the brake specific fuel consumption and brake thermal efficiency, while NOx emissions was increased when the engine is operated with biodiesel blends.

  10. Demonstrating the Performance and Emission Characteristics of a Variable Compression Ratio, Alvar-Cycle Engine

    OpenAIRE

    Erlandsson, Olof; Lundholm, Gunnar; Söderberg, Fredrik; Johansson, Bengt; Wong, Victor W.

    1998-01-01

    This paper is a direct continuation of a previous study that addressed the performance and design of a variable compression engine, the Alvar-Cycle Engine [1]. The earlier study was presented at the SAE International Conference and Exposition in Detroit during February 23- 26, 1998 as SAE paper 981027. In the present paper test results from a single cylinder prototype are reviewed and compared with a similar conventional engine. Efficiency and emissions are shown as fu...

  11. PTR-MS monitoring of volatiles fingerprint evolution during grape must cooking

    NARCIS (Netherlands)

    Dimitri, G.; Ruth, van S.M.; Sacchetti, G.; Piva, G.; Alewijn, M.; Arfelli, G.

    2013-01-01

    The main aim of this study was to investigate the effect of processing temperature on the evolution of volatiles during grape must concentration upon cooking. The evolution of the volatiles fingerprint of grape must heated at 80, 90, and 100 °C was studied by Proton Transfer Reaction Mass

  12. Use of a PTR-MS for Multicomponent Flux Measurements over a Forest

    Energy Technology Data Exchange (ETDEWEB)

    Dommen, J; Spirig, C [FAL Reckenholz (Switzerland); Neftel, A [FAL Reckenholz (Switzerland); Thielmann, A [MPI Mainz (Georgia)

    2004-03-01

    A proton-transfer-reaction mass spectrometer was used to determine fluxes of biogenically emitted organic compounds over a forest canopy with the eddy covariance method. It was shown that several compounds can be simultaneously measured at a frequency high enough to calculate their fluxes. (author)

  13. Plant-specific volatile organic compound emission rates from young and mature leaves of Mediterranean vegetation

    Science.gov (United States)

    Bracho-Nunez, Araceli; Welter, Saskia; Staudt, Michael; Kesselmeier, Jürgen

    2011-08-01

    The seasonality of vegetation, i.e., developmental stages and phenological processes, affects the emission of volatile organic compounds (VOCs). Despite the potential significance, the contributions of seasonality to VOC emission quality and quantity are not well understood and are therefore often ignored in emission simulations. We investigated the VOC emission patterns of young and mature leaves of several Mediterranean plant species in relation to their physiological and developmental changes during the growing period and estimated Es. Foliar emissions of isoprenoids and oxygenated VOCs like methanol and acetone were measured online by means of a proton transfer reaction mass spectrometer (PTR-MS) and offline with gas chromatography coupled with a mass spectrometer and flame ionization detector. The results suggest that VOC emission is a developmentally regulated process and that quantitative and qualitative variability is plant species specific. Leaf ontogeny clearly influenced both the VOC Es and the relative importance of different VOCs. Methanol was the major compound contributing to the sum of target VOC emissions in young leaves (11.8 ± 10.4 μg g-1 h-1), while its contribution was minor in mature leaves (4.1 ± 4.1 μg g-1 h-1). Several plant species showed a decrease or complete subsidence of monoterpene, sesquiterpene, and acetone emissions upon maturity, perhaps indicating a potential response to the higher defense demands of young emerging leaves.

  14. Combining emission inventory and isotope ratio analyses for quantitative source apportionment of heavy metals in agricultural soil.

    Science.gov (United States)

    Chen, Lian; Zhou, Shenglu; Wu, Shaohua; Wang, Chunhui; Li, Baojie; Li, Yan; Wang, Junxiao

    2018-08-01

    Two quantitative methods (emission inventory and isotope ratio analysis) were combined to apportion source contributions of heavy metals entering agricultural soils in the Lihe River watershed (Taihu region, east China). Source apportionment based on the emission inventory method indicated that for Cd, Cr, Cu, Pb, and Zn, the mean percentage input from atmospheric deposition was highest (62-85%), followed by irrigation (12-27%) and fertilization (1-14%). Thus, the heavy metals were derived mainly from industrial activities and traffic emissions. For Ni the combined percentage input from irrigation and fertilization was approximately 20% higher than that from atmospheric deposition, indicating that Ni was mainly derived from agricultural activities. Based on isotope ratio analysis, atmospheric deposition accounted for 57-93% of Pb entering soil, with the mean value of 69.3%, which indicates that this was the major source of Pb entering soil in the study area. The mean contributions of irrigation and fertilization to Pb pollution of soil ranged from 0% to 10%, indicating that they played only a marginally important role. Overall, the results obtained using the two methods were similar. This study provides a reliable approach for source apportionment of heavy metals entering agricultural soils in the study area, and clearly have potential application for future studies in other regions. Copyright © 2018 Elsevier Ltd. All rights reserved.

  15. Stimulus Ratio and Level Dependence of Low- and Mid-Frequency Distortion-Product Otoacoustic Emissions

    DEFF Research Database (Denmark)

    Christensen, Anders Tornvig; Ordoñez, Rodrigo Pizarro; Hammershøi, Dorte

    2014-01-01

    ratios f2/f1 (1.05-1.50) and three stimulus sound pressure levels L1/L2 (65/45, 65/55, 70/60) were measured in each configuration. The DPOAE response was isolated with the discrete Fourier transformation (DFT). The DFT measures the DPOAE response accurately only when the DPOAE frequency and both stimulus...... examples of low-frequency DPOAEs exist in the literature. Overcoming the decreasing response level and increasing noise level with decreasing frequency may provide a non-invasive window into the inner-ear mechanics of low-frequency hearing. Eighteen out of 21 young human adults screened (19-30 years) had......-frequency range. The stimulus level has similar effects in both frequency ranges, that is, the ratio-magnitude response increases and broadens with increasing level. The combined observations could indicate a difference between apical and basal cochlear physiology....

  16. Effects of laser wavelengths and pulse energy ratio on the emission enhancement in dual pulse LIBS

    International Nuclear Information System (INIS)

    Ahmed, Rizwan; Iqbal, Javed; Baig, M Aslam

    2015-01-01

    We present new studies on the effects of laser wavelengths, pulse energy ratio and interpulse delay between two laser pulses in the collinear dual pulse configuration of laser-induced breakdown spectroscopy (LIBS) on an iron sample in air using the fundamental (1064 nm) and the second harmonics (532 nm) of Nd:YAG lasers. In the dual pulse LIBS, an optimum value of interpulse delay with an appropriate combination of laser wavelengths, and laser pulse energy ratio, yields a 30 times signal intensity enhancement in the neutral iron lines as compared with single pulse LIBS. A comparison in the spatial variations of electron temperature along the axis of the plume expansion in single and double pulse LIBS has also been studied. (letter)

  17. Effects of mix ratio, moisture content and aeration rate on sulfur odor emissions during pig manure composting.

    Science.gov (United States)

    Zang, Bing; Li, Shuyan; Michel, Frederick; Li, Guoxue; Luo, Yuan; Zhang, Difang; Li, Yangyang

    2016-10-01

    Sulfur compounds in swine manure can cause odor emissions during composting if conditions are not conducive to their rapid oxidation and degradation. In this study, the effects of controllable composting process variables on sulfur odor emissions were investigated. These included pig manure to corn stalk mix ratio (0.7:1, 1.5:1 and 2.2:1dw basis), initial moisture content (60%, 65%, 70% and 75%) and aeration rate (1.0, 2.0, 3.0 and 4.0m(3)m(-3)h(-1)). The compounds measured were carbonyl sulfide, carbon disulfide, hydrogen sulfide, methyl mercaptan, ethyl mercaptan, diethyl sulfide, dimethyl sulfide (Me2S) and dimethyl disulfide (Me2SS). The results showed that total sulfur losses ranged from 3.9% to 18.3% after 26days of composting. Me2S and Me2SS were the primary (>59.61%) sulfur compounds released during this period. After turning, emission rates of both Me2S and Me2SS increased. Emissions of the other six sulfur compounds were low and inconsistent during composting. Within the compost, feedstock mix ratio significantly influenced the concentration of Me2SS, while aeration rate significantly affected Me2S concentration (pMoisture content did not have a significant effect on the concentrations of either of these two compounds. Concentrations of sulfur odor compounds were the lowest at the highest aeration rate. Therefore, high aeration rates during the thermophilic phase, especially after turning, are recommended to minimize sulfur odors produced during swine manure composting. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Constraining a hybrid volatility basis-set model for aging of wood-burning emissions using smog chamber experiments: a box-model study based on the VBS scheme of the CAMx model (v5.40)

    Science.gov (United States)

    Ciarelli, Giancarlo; El Haddad, Imad; Bruns, Emily; Aksoyoglu, Sebnem; Möhler, Ottmar; Baltensperger, Urs; Prévôt, André S. H.

    2017-06-01

    In this study, novel wood combustion aging experiments performed at different temperatures (263 and 288 K) in a ˜ 7 m3 smog chamber were modelled using a hybrid volatility basis set (VBS) box model, representing the emission partitioning and their oxidation against OH. We combine aerosol-chemistry box-model simulations with unprecedented measurements of non-traditional volatile organic compounds (NTVOCs) from a high-resolution proton transfer reaction mass spectrometer (PTR-MS) and with organic aerosol measurements from an aerosol mass spectrometer (AMS). Due to this, we are able to observationally constrain the amounts of different NTVOC aerosol precursors (in the model) relative to low volatility and semi-volatile primary organic material (OMsv), which is partitioned based on current published volatility distribution data. By comparing the NTVOC / OMsv ratios at different temperatures, we determine the enthalpies of vaporization of primary biomass-burning organic aerosols. Further, the developed model allows for evaluating the evolution of oxidation products of the semi-volatile and volatile precursors with aging. More than 30 000 box-model simulations were performed to retrieve the combination of parameters that best fit the observed organic aerosol mass and O : C ratios. The parameters investigated include the NTVOC reaction rates and yields as well as enthalpies of vaporization and the O : C of secondary organic aerosol surrogates. Our results suggest an average ratio of NTVOCs to the sum of non-volatile and semi-volatile organic compounds of ˜ 4.75. The mass yields of these compounds determined for a wide range of atmospherically relevant temperatures and organic aerosol (OA) concentrations were predicted to vary between 8 and 30 % after 5 h of continuous aging. Based on the reaction scheme used, reaction rates of the NTVOC mixture range from 3.0 × 10-11 to 4. 0 × 10-11 cm3 molec-1 s-1. The average enthalpy of vaporization of secondary organic aerosol

  19. Constraining a hybrid volatility basis-set model for aging of wood-burning emissions using smog chamber experiments: a box-model study based on the VBS scheme of the CAMx model (v5.40

    Directory of Open Access Journals (Sweden)

    G. Ciarelli

    2017-06-01

    Full Text Available In this study, novel wood combustion aging experiments performed at different temperatures (263 and 288 K in a ∼ 7 m3 smog chamber were modelled using a hybrid volatility basis set (VBS box model, representing the emission partitioning and their oxidation against OH. We combine aerosol–chemistry box-model simulations with unprecedented measurements of non-traditional volatile organic compounds (NTVOCs from a high-resolution proton transfer reaction mass spectrometer (PTR-MS and with organic aerosol measurements from an aerosol mass spectrometer (AMS. Due to this, we are able to observationally constrain the amounts of different NTVOC aerosol precursors (in the model relative to low volatility and semi-volatile primary organic material (OMsv, which is partitioned based on current published volatility distribution data. By comparing the NTVOC ∕ OMsv ratios at different temperatures, we determine the enthalpies of vaporization of primary biomass-burning organic aerosols. Further, the developed model allows for evaluating the evolution of oxidation products of the semi-volatile and volatile precursors with aging. More than 30 000 box-model simulations were performed to retrieve the combination of parameters that best fit the observed organic aerosol mass and O : C ratios. The parameters investigated include the NTVOC reaction rates and yields as well as enthalpies of vaporization and the O : C of secondary organic aerosol surrogates. Our results suggest an average ratio of NTVOCs to the sum of non-volatile and semi-volatile organic compounds of ∼ 4.75. The mass yields of these compounds determined for a wide range of atmospherically relevant temperatures and organic aerosol (OA concentrations were predicted to vary between 8 and 30 % after 5 h of continuous aging. Based on the reaction scheme used, reaction rates of the NTVOC mixture range from 3.0 × 10−11 to 4. 0 × 10−11 cm3 molec−1 s−1

  20. Theoretical emission line ratios for [Fe III] and [Fe VII] applicable to the optical and infrared spectra of gaseous nebulae.

    Science.gov (United States)

    Keenan, F P; Aller, L H; Ryans, R S; Hyung, S

    2001-08-14

    Recent calculations of electron impact excitation rates and Einstein A-coefficients for transitions among the 3d(6) levels of Fe III and among the 3d(2) levels of Fe VII are used to derive theoretical emission line ratios applicable to the optical and infrared spectra of gaseous nebulae. Results for [Fe III] are generated for electron temperatures T(e) = 7,000-20,000 K and densities N(e) = 10(2)-10(8) cm(-3), whereas those for [Fe VII] are provided for T(e) = 10,000-30,000 K and N(e) = 10(2)-10(8) cm(-3). The theoretical line ratios are significantly different in some instances from earlier calculations and resolve discrepancies between theory and observation found for the planetary nebulae IC 4997 and NGC 7027.

  1. Calculation of lung-heart ratios for single-photon emission computed tomography

    International Nuclear Information System (INIS)

    Soares, E.J.; King, M.A.; Glick, S.J.; Villegas, B.J.

    1996-01-01

    The authors investigate the effectiveness of simple iterative reconstruction techniques in calculating lung-heart activity ratios (LHRs). The LHR has been shown to be an effective indicator of the severity of coronary artery disease in cardiac SPECT. A study was conducted with a mathematical cardiac torso phantom that modelled uptake of 201 Tl in the heart and lung regions. The projection data included only the effects of nonuniform photon attenuation. The data were first reconstructed with zeroth-order Chang and a variant of the Bellini method, both of which utilize information from the nonuniform attenuation map. This nonuniform (NU) Bellini method compensates exactly for attenuation in the heart region, but is incorrect for other regions in the medium. These reconstructions were then used as the initial estimates in the iterative Chang, variable step-size (VSS) Chang, and Morozumi methods,m for one and five iterations. The average heart count (AHC) and average lung count (ALC) were calculated using region-of-interest (ROI) templates derived from the true activity map. The population mean LHR was tabulated as the ratio of the ALC to AHC. Using the same reconstruction procedure, the authors also calculated the sample mean LHR and standard deviation from 21 noisy 3D reconstructions

  2. Effects of carbon sources and COD/N ratio on N2O emissions in subsurface flow constructed wetlands.

    Science.gov (United States)

    Lyu, Wanlin; Huang, Lei; Xiao, Guangquan; Chen, Yucheng

    2017-12-01

    A set of constructed wetlands under two different carbon sources, namely, glucose (CW) and sodium acetate (YW), was established at a laboratory scale with influent COD/N ratios of 20:1, 10:1, 7:1, 4:1, and 0 to analyze the influence of carbon supply on nitrous oxide emissions. Results showed that the glucose systems generated higher N 2 O emissions than those of the sodium acetate systems. The higher amount of N 2 O-releasing fluxes in the CWs than in the YWs was consistent with the higher NO 2 - -N accumulation in the former than in the latter. Moreover, electron competition was tighter in the CWs and contributed to the incomplete denitrification with poor N 2 O production performance. Illumina MiSeq sequencing demonstrated that some denitrifying bacteria, such as Denitratisoma, Bacillus, and Zoogloea, were higher in the YWs than in the CWs. This result indicated that the carbon source is important in controlling N 2 O emissions in microbial communities. Copyright © 2017. Published by Elsevier Ltd.

  3. High-aspect-ratio HfC nanobelts accompanied by HfC nanowires: Synthesis, characterization and field emission properties

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Song, E-mail: tiansong22@126.com [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072 (China); School of Materials Science and Engineering, Chongqing Jiaotong University, Chongqing 400074 (China); Zhang, Yulei; Ren, Jincui; Qiang, Xinfa; Zhang, Shouyang [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072 (China); Li, Hejun, E-mail: lihejun@nwpu.edu.cn [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072 (China)

    2017-04-30

    Highlights: • HfC naobelts accompanied by HfC nanowires were synthesized by a catalytic CVD method. • HfC nanobelts as a novel structure of HfC ceramic are reported for the first time. • HfC nanobelts have 100–200 μm in lengths and reach up to 10 μm in widths. • The synthesized product is promising field nanoemitters. - Abstract: As a key refractory carbide, hafnium carbide (HfC) is commonly used as structural materials while the field emission (FE) application of HfC in the field of vacuum microelectronics is almost the only one for functional material purposes. Based on its outstanding physical and chemical characteristics, HfC is identified as a potential candidate with satisfactory mechanical properties and long-term and/or high-temperature FE stability for future applications in high-performance field emitters. However, the development of HfC in various FE applications is hindered because it is not facile to fabricate large-scale low-dimensional HfC field nanoemitters. Herein, High-aspect-ratio HfC nanobelts accompanied by HfC nanowires were synthesized on a large scale by a traditional and simple catalytic chemical vapor deposition (CVD) method. Classical vapor–liquid–solid (VLS) theory was employed to explain the growth of the HfC nanowires and nanobelts along axial direction. The thin HfO{sub 2} shell and thin C layer surrounding the nanostructures might give rise to the diameter fluctuation of HfC nanowires and the width increase of HfC nanobelts in lateral direction. Field emission results show that the high-aspect-ratio HfC nanobelts accompanied by the nanowires are promising field nanoemitters, which exhibit excellent field emission properties with a fairly low turn-on field of ∼1.5 V μm{sup −1} and a low current fluctuation less than ∼10%. This suggests that HfC ceramics with high-aspect-ratio nanostructures are ideal cathode material for various field emission applications.

  4. Lyman alpha emission in nearby star-forming galaxies with the lowest metallicities and the highest [OIII]/[OII] ratios

    Science.gov (United States)

    Izotov, Yuri

    2017-08-01

    The Lyman alpha line of hydrogen is the strongest emission line in galaxies and the tool of predilection for identifying and studying star-forming galaxies over a wide range of redshifts, especially in the early universe. However, it has become clear over the years that not all of the Lyman alpha radiation escapes, due to its resonant scattering on the interstellar and intergalactic medium, and absorption by dust. Although our knowledge of the high-z universe depends crucially on that line, we still do not have a complete understanding of the mechanisms behind the production, radiative transfer and escape of Lyman alpha in galaxies. We wish here to investigate these mechanisms by studying the properties of the ISM in a unique sample of 8 extreme star-forming galaxies (SFGs) that have the highest excitation in the SDSS spectral data base. These dwarf SFGs have considerably lower stellar masses and metallicities, and higher equivalent widths and [OIII]5007/[OII]3727 ratios compared to all nearby SFGs with Lyman alpha emission studied so far with COS. They are, however, very similar to the dwarf Lyman alpha emitters at redshifts 3-6, which are thought to be the main sources of reionization in the early Universe. By combining the HST/COS UV data with data in the optical range, and using photoionization and radiative transfer codes, we will be able to study the properties of the Lyman alpha in these unique objects, derive column densities of the neutral hydrogen N(HI) and compare them with N(HI) obtained from the HeI emission-line ratios in the optical spectra. We will derive Lyman alpha escape fractions and indirectly Lyman continuum escape fractions.

  5. A combined plant and reaction chamber setup to investigate the effect of pollution and UV-B radiation on biogenic emissions

    Science.gov (United States)

    Timkovsky, J.; Gankema, P.; Pierik, R.; Holzinger, R.

    2012-12-01

    Biogenic emissions account for almost 90% of total non-methane organic carbon emissions in the atmosphere. The goal of this project is to study the effect of pollution (ozone, NOx) and UV radiation on the emission of real plants. We have designed and built a setup where we combine plant chambers with a reaction chamber (75L volume) allowing the addition of pollutants at different locations. The main analytical tool is a PTR-TOF-MS instrument that can be optionally coupled with a GC system for improved compound identification. The setup is operational since March 2012 and first measurements indicate interesting results, three types of experiments will be presented: 1. Ozonolysis of b-pinene. In this experiment the reaction chamber was flushed with air containing b-pinene at approximate levels of 50 nmol/mol. After ~40 min b-pinene levels reached equilibrium in the reaction chamber and a constant supply of ozone was provided. Within 30 minutes this resulted in a 10 nmol/mol decrease of b-pinene levels in accordance with a reaction rate constant of 1.5*10-17 cm3molec-1s-1 and a residence time of 10 minutes in the reaction chamber. In addition we observed known oxidation products such as formaldehyde, acetone, and nopinone the molar yields of which were also in accordance with reported values. 2. Ozonolysis of biogenic emissions from tomato plants. The air containing the emissions from tomato plants was supplied to the reaction chamber. After adding ozone we observed the decrease of monoterpene concentrations inside the reaction chamber. The observed decrease is consistent for online PTR-MS and GC/PTR-MS measurements. Several ozonolysis products have been observed in the chamber. 3. The effect of UV-B radiation on biogenic emissions of tomato plants. Tomato plants were exposed to UV-B radiation and their emissions measured during and after the treatment. We observed significant changes in the emissions of volatile organic compounds, with specific compounds increasing

  6. Modeling signal-to-noise ratio of otoacoustic emissions in workers exposed to different industrial noise levels

    Directory of Open Access Journals (Sweden)

    Parvin Nassiri

    2016-01-01

    Full Text Available Introduction: Noise is considered as the most common cause of harmful physical effects in the workplace. A sound that is generated from within the inner ear is known as an otoacoustic emission (OAE. Distortion-product otoacoustic emissions (DPOAEs assess evoked emission and hearing capacity. The aim of this study was to assess the signal-to-noise ratio in different frequencies and at different times of the shift work in workers exposed to various levels of noise. It was also aimed to provide a statistical model for signal-to-noise ratio (SNR of OAEs in different frequencies based on the two variables of sound pressure level (SPL and exposure time. Materials and Methods: This case–control study was conducted on 45 workers during autumn 2014. The workers were divided into three groups based on the level of noise exposure. The SNR was measured in frequencies of 1000, 2000, 3000, 4000, and 6000 Hz in both ears, and in three different time intervals during the shift work. According to the inclusion criterion, SNR of 6 dB or greater was included in the study. The analysis was performed using repeated measurements of analysis of variance, spearman correlation coefficient, and paired samples t-test. Results: The results showed that there was no statistically significant difference between the three exposed groups in terms of the mean values of SNR (P > 0.05. Only in signal pressure levels of 88 dBA with an interval time of 10:30–11:00 AM, there was a statistically significant difference between the right and left ears with the mean SNR values of 3000 frequency (P = 0.038. The SPL had a significant effect on the SNR in both the right and left ears (P = 0.023, P = 0.041. The effect of the duration of measurement on the SNR was statistically significant in both the right and left ears (P = 0.027, P < 0.001. Conclusion: The findings of this study demonstrated that after noise exposure during the shift, SNR of OAEs reduced from the

  7. Nitrous oxide emissions from yellow brown soil as affected by incorporation of crop residues with different carbon-to-nitrogen ratios: a case study in central China.

    Science.gov (United States)

    Lin, Shan; Iqbal, Javed; Hu, Ronggui; Shaaban, Muhammad; Cai, Jianbo; Chen, Xi

    2013-08-01

    To investigate the influence of crop residues decomposition on nitrous oxide (N2O) emission, a field study was performed with application of crop residues with different C:N ratios in a bare yellow brown soil at the experimental station of Zhangjiachong at Zigui, China. We set up six experimental treatments: no crop residue (CK), rapeseed cake (RC), potato stalk (PS), rice straw (RS), wheat straw (WS), and corn straw (CS). The carbon (C) to nitrogen (N) ratios of these crop residues were 7.5, 32.9, 40.4, 65.7, and 90.9, respectively. Nitrous oxide fluxes were measured using a static closed chamber method. N2O emissions were significantly enhanced by incorporation of crop residues. Cumulative N2O emissions negatively correlated with C:N ratio (R (2) = 0.9821) of the crop residue, but they were positively correlated with average concentrations of dissolved organic carbon and microbial biomass carbon. Nitrogen emission fraction, calculated as N2O-N emissions originated from the crop residues N, positively correlated with C:N ratio of the residues (P emissions because a significant correlation (P emissions in all treatments except the control. In contrast, a significant relationship between soil moisture and N2O emissions was found in the control only. Furthermore, N2O emission significantly correlated (P carbon and nitrogen contents can significantly alter soil N2O flux rates; and (2) soil biotic as well as abiotic variables are critical in determining soil-atmospheric N2O emissions after crop residue incorporation into soil.

  8. Qualitative tissue differentiation by analysing the intensity ratios of atomic emission lines using laser induced breakdown spectroscopy (LIBS): prospects for a feedback mechanism for surgical laser systems.

    Science.gov (United States)

    Kanawade, Rajesh; Mahari, Fanuel; Klämpfl, Florian; Rohde, Maximilian; Knipfer, Christian; Tangermann-Gerk, Katja; Adler, Werner; Schmidt, Michael; Stelzle, Florian

    2015-01-01

    The research work presented in this paper focuses on qualitative tissue differentiation by monitoring the intensity ratios of atomic emissions using 'Laser Induced Breakdown Spectroscopy' (LIBS) on the plasma plume created during laser tissue ablation. The background of this study is to establish a real time feedback control mechanism for clinical laser surgery systems during the laser ablation process. Ex-vivo domestic pig tissue samples (muscle, fat, nerve and skin) were used in this experiment. Atomic emission intensity ratios were analyzed to find a characteristic spectral line for each tissue. The results showed characteristic elemental emission intensity ratios for the respective tissues. The spectral lines and intensity ratios of these specific elements varied among the different tissue types. The main goal of this study is to qualitatively and precisely identify different tissue types for tissue specific laser surgery. © 2015 The Authors. Journal of Biophotonics published by WILEY-VCH Verlag.

  9. Influence of fuel type, dilution and equivalence ratio on the emission reduction from the auto-ignition in an Homogeneous Charge Compression Ignition engine

    Energy Technology Data Exchange (ETDEWEB)

    Machrafi, Hatim [UPMC Universite Paris 06, ENSCP, 11 rue de Pierre et Marie Curie, 75005 Paris (France); UPMC Universite Paris 06, Institut Jean Le Rond D' Alembert, 4 place Jussieu, 75252 Paris cedex 05 (France); Universite Libre de Bruxelles, TIPs - Fluid Physics, CP165/67, 50 Avenue F.D. Roosevelt, 1050 Brussels (Belgium); Cavadias, Simeon [UPMC Universite Paris 06, ENSCP, 11 rue de Pierre et Marie Curie, 75005 Paris (France); UPMC Universite Paris 06, Institut Jean Le Rond D' Alembert, 4 place Jussieu, 75252 Paris cedex 05 (France); Amouroux, Jacques [UPMC Universite Paris 06, ENSCP, 11 rue de Pierre et Marie Curie, 75005 Paris (France)

    2010-04-15

    One technology that seems to be promising for automobile pollution reduction is the Homogeneous Charge Compression Ignition (HCCI). This technology still faces auto-ignition and emission-control problems. This paper focuses on the emission problem, since it is incumbent to realize engines that pollute less. For this purpose, this paper presents results concerning the measurement of the emissions of CO, NO{sub x}, CO{sub 2}, O{sub 2} and hydrocarbons. HCCI conditions are used, with equivalence ratios between 0.26 and 0.54, inlet temperatures of 70 C and 120 C and compression ratios of 10.2 and 13.5, with different fuel types: gasoline, gasoline surrogate, diesel, diesel surrogate and mixtures of n-heptane/toluene. The effect of dilution is considered for gasoline, while the effect of the equivalence ratio is considered for all the fuels. No significant amount of NO{sub x} has been measured. It appeared that the CO, O{sub 2} and hydrocarbon emissions were reduced by decreasing the toluene content of the fuel and by decreasing the dilution. The opposite holds for CO{sub 2}. The reduction of the hydrocarbon emission appears to compete with the reduction of the CO{sub 2} emission. Diesel seemed to produce less CO and hydrocarbons than gasoline when auto-ignited. An example of emission reduction control is presented in this paper. (author)

  10. Performance and emission characteristics of LPG powered four stroke SI engine under variable stroke length and compression ratio

    International Nuclear Information System (INIS)

    Ozcan, Hakan; Yamin, Jehad A.A.

    2008-01-01

    A computer simulation of a variable stroke length, LPG fuelled, four stroke, single cylinder, water cooled spark ignition engine was done. The engine capacity was varied by varying the stroke length of the engine, which also changed its compression ratio. The simulation model developed was verified with experimental results from the literature for both constant and variable stroke engines. The performance of the engine was simulated at each stroke length/compression ratio combination. The simulation results clearly indicate the advantages and utility of variable stroke engines in fuel economy and power issues. Using the variable stroke technique has significantly improved the engine's performance and emission characteristics within the range studied. The brake torque and power have registered an increase of about 7-54% at low speed and 7-57% at high speed relative to the original engine design and for all stroke lengths and engine speeds studied. The brake specific fuel consumption has registered variations from a reduction of about 6% to an increase of about 3% at low speed and from a reduction of about 6% to an increase of about 8% at high speed relative to the original engine design and for all stroke lengths and engine speeds studied. On the other hand, an increase of pollutants of about 0.65-2% occurred at low speed. Larger stroke lengths resulted in a reduction of the pollutants level of about 1.5% at higher speeds. At lower stroke lengths, on the other hand, an increase of about 2% occurred. Larger stroke lengths resulted in increased exhaust temperature and, hence, make the exhaust valve work under high temperature

  11. Performance and emission characteristics of a turbocharged CNG engine fueled by hydrogen-enriched compressed natural gas with high hydrogen ratio

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Fanhua; Wang, Mingyue; Jiang, Long; Chen, Renzhe; Deng, Jiao; Naeve, Nashay; Zhao, Shuli [State Key Laboratory of Automotive Safety and Energy Tsinghua University, Beijing 100084 (China)

    2010-06-15

    This paper investigates the effect of high hydrogen volumetric ratio of 55% on performance and emission characteristics in a turbocharged lean burn natural gas engine. The experimental data was conducted under various operating conditions including different spark timing, excess air ratio (lambda), and manifold pressure. It is found that the addition of hydrogen at a high volumetric ratio could significantly extend the lean burn limit, improve the engine lean burn ability, decrease burn duration, and yield higher thermal efficiency. The CO, CH{sub 4} emissions were reduced and NO{sub x} emission could be kept an acceptable low level with high hydrogen content under lean burn conditions when ignition timing were optimized. (author)

  12. Changes of the carbon dioxide emissions and the overshoot ratio resulting from the implementation of the 2nd Energy Master Plan in the Republic of Korea

    International Nuclear Information System (INIS)

    Yeo, M.J.; Kim, Y.P.

    2016-01-01

    Based on the national greenhouse gas emission reduction target for 2030 (“GHG target for 2030″) and the 2nd Energy Master Plan (“2nd EMP”), several power mix configuration scenarios were tested to estimate the sensitivity of the carbon dioxide emissions and the ‘overshoot ratio’, which is the ratio of ecological footprint to biocapacity. It would be only possible to achieve the GHG target for 2030 if the fraction of non-emission energy be more than 70% of the total input primary energy for power generation with the current conversion efficiency (40%). Even the conversion efficiency is changed to 50%, still the carbon dioxide emissions are larger than the targeted carbon dioxide emissions from the energy sector. The overshoot ratio would still increase from 5.9 in 2009 to 7.6 in 2035 even with the successful implementation of the 2nd EMP. Thus, additional efforts to reduce the carbon dioxide emissions and the overshoot ratio from the energy sector are required beyond adjusting the supply mix configuration for power generation and the conversion efficiency. Policies and programs encouraging the changes in consumer behavior toward reduction of goods consumption and energy savings are expected to impact on reducing the carbon dioxide emissions and the overshoot ratio. - Highlights: •The overshoot ratio will increase in 2035 even if the 2nd EMP is fully implemented. •Power mix configuration changes would not be enough to achieve the GHG target. •Increasing the conversion efficiency is good in long-term to achieve the GHG target.

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

    Science.gov (United States)

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

    2017-09-01

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

  14. Carbon dioxide emissions and the overshoot ratio change resulting from the implementation of 2nd Energy Master Plan in South Korea

    Science.gov (United States)

    Yeo, M. J.; Kim, Y. P.

    2015-12-01

    The direction of the energy policies of the country is important in the projection of environmental impacts of the country. The greenhouse gases (GHGs) emission of the energy sector in South Korea is very huge, about 600 MtCO2e in 2011. Also the carbon footprint due to the energy consumption contributes to the ecological footprint is also large, more than 60%. Based on the official plans (the national greenhouse gases emission reduction target for 2030 (GHG target for 2030) and the 2nd Energy Master Plan (2nd EMP)), several scenarios were proposed and the sensitivity of the GHG emission amount and 'overshoot ratio' which is the ratio of ecological footprint to biocapacity were estimated. It was found that to meet the GHG target for 2030 the ratio of non-emission energy for power generation should be over 71% which would be very difficult. We also found that the overshoot ratio would increase from 5.9 in 2009 to 7.6 in 2035. Thus, additional efforts are required to reduce the environmental burdens in addition to optimize the power mix configuration. One example is the conversion efficiency in power generation. If the conversion efficiency in power generation rises up 50% from the current level, 40%, the energy demand and resultant carbon dioxide emissions would decrease about 10%. Also the influence on the environment through changes in consumption behavior, for example, the diet choice is expected to be meaningful.

  15. Continued increase of CFC-113a (CCl3CF3) mixing ratios in the global atmosphere: emissions, occurrence and potential sources

    Science.gov (United States)

    Adcock, Karina E.; Reeves, Claire E.; Gooch, Lauren J.; Leedham Elvidge, Emma C.; Ashfold, Matthew J.; Brenninkmeijer, Carl A. M.; Chou, Charles; Fraser, Paul J.; Langenfelds, Ray L.; Hanif, Norfazrin Mohd; O'Doherty, Simon; Oram, David E.; Ou-Yang, Chang-Feng; Moi Phang, Siew; Abu Samah, Azizan; Röckmann, Thomas; Sturges, William T.; Laube, Johannes C.

    2018-04-01

    Atmospheric measurements of the ozone-depleting substance CFC-113a (CCl3CF3) are reported from ground-based stations in Australia, Taiwan, Malaysia and the United Kingdom, together with aircraft-based data for the upper troposphere and lower stratosphere. Building on previous work, we find that, since the gas first appeared in the atmosphere in the 1960s, global CFC-113a mixing ratios have been increasing monotonically to the present day. Mixing ratios of CFC-113a have increased by 40 % from 0.50 to 0.70 ppt in the Southern Hemisphere between the end of the previously published record in December 2012 and February 2017. We derive updated global emissions of 1.7 Gg yr-1 on average between 2012 and 2016 using a two-dimensional model. We compare the long-term trends and emissions of CFC-113a to those of its structural isomer, CFC-113 (CClF2CCl2F), which still has much higher mixing ratios than CFC-113a, despite its mixing ratios and emissions decreasing since the 1990s. The continued presence of northern hemispheric emissions of CFC-113a is confirmed by our measurements of a persistent interhemispheric gradient in its mixing ratios, with higher mixing ratios in the Northern Hemisphere. The sources of CFC-113a are still unclear, but we present evidence that indicates large emissions in East Asia, most likely due to its use as a chemical involved in the production of hydrofluorocarbons. Our aircraft data confirm the interhemispheric gradient as well as showing mixing ratios consistent with ground-based observations and the relatively long atmospheric lifetime of CFC-113a. CFC-113a is the only known CFC for which abundances are still increasing substantially in the atmosphere.

  16. Combustion and emissions characteristics of high n-butanol/diesel ratio blend in a heavy-duty diesel engine and EGR impact

    International Nuclear Information System (INIS)

    Chen, Zheng; Wu, Zhenkuo; Liu, Jingping; Lee, Chiafon

    2014-01-01

    Highlights: • Effects of EGR on high n-butanol/diesel ratio blend (Bu40) were investigated and compared with neat diesel (Bu00). • Bu40 has higher NOx due to wider combustion high-temperature region. • Bu40 has lower soot due to local lower equivalence ratio distribution. • Bu40 has higher CO due to lower gas temperature in the late expansion process. • For Bu40, EGR reduces NOx emissions dramatically with no obvious influence on soot. - Abstract: In this work, the combustion and emission fundamentals of high n-butanol/diesel ratio blend with 40% butanol (i.e., Bu40) in a heavy-duty diesel engine were investigated by experiment and simulation at constant engine speed of 1400 rpm and an IMEP of 1.0 MPa. Additionally, the impact of EGR was evaluated experimentally and compared with neat diesel fuel (i.e., Bu00). The results show that Bu40 has higher cylinder pressure, longer ignition delay, and faster burning rate than Bu00. Compared with Bu00, moreover, Bu40 has higher NOx due to wider combustion high-temperature region, lower soot due to local lower equivalence ratio distribution, and higher CO due to lower gas temperature in the late expansion process. For Bu40, EGR reduces NOx emissions dramatically with no obvious influence on soot. Meanwhile, there is no significant change in HC and CO emissions and indicated thermal efficiency (ITE) with EGR until EGR threshold is reached. When EGR rate exceeds the threshold level, HC and CO emissions increase dramatically, and ITE decreases markedly. Compared with Bu00, the threshold of Bu40 appears at lower EGR rate. Consequently, combining high butanol/diesel ratio blend with medium EGR has the potential to achieve ultra-low NOx and soot emissions simultaneously while maintaining high thermal efficiency level

  17. Characterization of polycyclic aromatic hydrocarbon emissions in the particulate and gas phase from smoldering mosquito coils containing various atomic hydrogen/carbon ratios

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Tzu-Ting, E-mail: d89844001@ntu.edu.tw [Department of Environmental Engineering and Health, Yuanpei University, No. 306, Yuanpei St., Hsin Chu 30015, Taiwan (China); Lin, Shaw-Tao [Department of Applied Chemistry, Providence University, No. 200 Chung-Chi Rd., Salu Dist., Taichung City 43301, Taiwan (China); Lin, Tser-Sheng [Department of Safety, Health, and Environmental Engineering, National United University, 2 Lien Da, Maioli 360, Taiwan (China); Chung, Hua-Yi [Department of Environmental Engineering and Health, Yuanpei University, No. 306, Yuanpei St., Hsin Chu 30015, Taiwan (China)

    2015-02-15

    The polycyclic aromatic hydrocarbon emissions in particulate and gas phases generated from smoldering mosquito coils containing various atomic H/C ratios were examined. Five types of mosquito coils were burned in a test chamber with a total airflow rate of 8.0 L/min at a constant relative humidity and temperature. The concentrations of individual PAHs were determined using the GC/MS technique. Among the used mosquito coils, the atomic H/C ratio ranged from 1.23 to 1.57, yielding total mass, gaseous, and particulate PAH emission factors of 28.17–78.72 mg/g, 26,139.80–35,932.98 and 5735.22–13,431.51 ng/g, respectively. The various partitions of PAHs in the gaseous and particulate phases were in the ranges, 70.26–83.70% and 16.30–29.74% for the utilized mosquito coils. The carcinogenic potency of PAH emissions in the particulate phase (203.82–797.76 ng/g) was approximately 6.92–25.08 times higher than that of the gaseous phase (26.27–36.07 ng/g). Based on the analyses of PAH emissions, mosquito coils containing the lowest H/C ratio, a low oxygen level, and additional additives (i.e., CaCO{sub 3}) are recommended for minimizing the production of total PAH emission factors and carcinogenic potency. - Highlights: • PAHs emissions are influenced by mosquito coils containing various atomic H/C ratios. • The PAHs generated by burning mosquito coils mainly occur in the gaseous phase. • Total TEQ emission factors of PAHs mainly consisted of the particulate phase (> 87%). • The BaP and BaA accounted for 71.13–77.28% of the total TEQ emission factors. • Special PAH ratios were regarded as characteristic ratios for burning mosquito coil.

  18. Polar and non-polar organic aerosols from large-scale agricultural-waste burning emissions in Northern India: Implications to organic mass-to-organic carbon ratio.

    Science.gov (United States)

    Rajput, Prashant; Sarin, M M

    2014-05-01

    This study focuses on characteristics of organic aerosols (polar and non-polar) and total organic mass-to-organic carbon ratio (OM/OC) from post-harvest agricultural-waste (paddy- and wheat-residue) burning emissions in Northern India. Aerosol samples from an upwind location (Patiala: 30.2°N, 76.3°E) in the Indo-Gangetic Plain were analyzed for non-polar and polar fractions of organic carbon (OC1 and OC2) and their respective mass (OM1 and OM2). On average, polar organic aerosols (OM2) contribute nearly 85% of the total organic mass (OM) from the paddy- and wheat-residue burning emissions. The water-soluble-OC (WSOC) to OC2 ratio, within the analytical uncertainty, is close to 1 from both paddy- and wheat-residue burning emissions. However, temporal variability and relatively low WSOC/OC2 ratio (Av: 0.67±0.06) is attributed to high moisture content and poor combustion efficiency during paddy-residue burning, indicating significant contribution (∼30%) of aromatic carbon to OC2. The OM/OC ratio for non-polar (OM1/OC1∼1.2) and polar organic aerosols (OM2/OC2∼2.2), hitherto unknown for open agricultural-waste burning emissions, is documented in this study. The total OM/OC ratio is nearly identical, 1.9±0.2 and 1.8±0.2, from paddy- and wheat-residue burning emissions. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. Experimental investigation of particle emissions under different EGR ratios on a diesel engine fueled by blends of diesel/gasoline/n-butanol

    International Nuclear Information System (INIS)

    Huang, Haozhong; Liu, Qingsheng; Wang, Qingxin; Zhou, Chengzhong; Mo, Chunlan; Wang, Xueqiang

    2016-01-01

    Highlights: • The effects of EGR and blend fuels on particulate emission were studied in CI engine. • EGR ⩽ 20%, gasoline or n-butanol increases total particulate number concentration. • EGR ⩾ 30%, gasoline or n-butanol reduces total particulate number concentration. • As EGR ratio increased, the particulate mass concentrations of four fuels increased. • Gasoline or n-butanol increases the ratio of sub-25 nm particles number concentration. - Abstract: The particle emission characteristics of a high-pressure common-rail engine under different EGR conditions were investigated, using pure diesel (D100), diesel/gasoline (with a volume ratio of 70:30, D70G30), diesel/n-butanol (with a volume ratio of 70:30, D70B30) and diesel/gasoline/n-butanol (with a volume ratio of 70:15:15, D70G15B15) for combustion. Our results show that, with increasing EGR ratios, the in-cylinder pressure peak decreases and the heat release is delayed for the combustion of each fuel. At an EGR ratio of 30%, the combustion pressure peaks of D70G30, D70B30, D70G15B15 and D100 have similar values; with an EGR ratio of 40%, the combustion pressure peaks and release rate peaks of D70G30 and D70G15B15 are both lower with respect to D100. For small and medium EGR ratios (⩽20%), after the addition of gasoline and/or n-butanol to the fuel, the total particle number concentration (TPNC) increases, while both the soot emissions and the average geometric size of particles decrease. At large EGR ratios (30% and 40%), the TPNC of D70B30, D70G15B15 and D70G20 compared to D100 are reduced by a maximum amount of 74.7%, 66.7% and 28.6%, respectively. As the EGR ratio increases, the total particle mass concentration increases gradually for all four fuels. Blending gasoline or/and n-butanol into diesel induces an increase in the number concentration of sub-25 nm particles (PN25) which may be harmful in terms of health. However, the PN25 decreases with increasing the EGR ratio for all the tested fuels

  20. The molar H: Corg ratio of biochar is a key factor in mitigating N2O emissions from soil

    NARCIS (Netherlands)

    Cayuela, M.L.; Jeffery, S.L.; Zwieten, van L.

    2015-01-01

    A previously published meta-analysis of biochar impacts on soil N2O emissions by Cayuela et al. (2014) found a “grand mean” reduction in N2O emissions of 54 ± 6% following biochar application to soil. Here we update this analysis to include 26 additional manuscripts bringing the total to 56

  1. Influence of the overfire air ratio on the NO(x) emission and combustion characteristics of a down-fired 300-MW(e) utility boiler.

    Science.gov (United States)

    Ren, Feng; Li, Zhengqi; Chen, Zhichao; Fan, Subo; Liu, Guangkui

    2010-08-15

    Down-fired boilers used to burn low-volatile coals have high NO(x) emissions. To find a way of solving this problem, an overfire air (OFA) system was introduced on a 300 MW(e) down-fired boiler. Full-scale experiments were performed on this retrofitted boiler to explore the influence of the OFA ratio (the mass flux ratio of OFA to the total combustion air) on the combustion and NO(x) emission characteristics in the furnace. Measurements were taken of gas temperature distributions along the primary air and coal mixture flows, average gas temperatures along the furnace height, concentrations of gases such as O(2), CO, and NO(x) in the near-wall region and carbon content in the fly ash. Data were compared for five different OFA ratios. The results show that as the OFA ratio increases from 12% to 35%, the NO(x) emission decreases from 1308 to 966 mg/Nm(3) (at 6% O(2) dry) and the carbon content in the fly ash increases from 6.53% to 15.86%. Considering both the environmental and economic effect, 25% was chosen as the optimized OFA ratio.

  2. Leaf level emissions of volatile organic compounds (VOC) from some Amazonian and Mediterranean plants

    Science.gov (United States)

    Bracho-Nunez, A.; Knothe, , N. M.; Welter, S.; Staudt, M.; Costa, W. R.; Liberato, M. A. R.; Piedade, M. T. F.; Kesselmeier, J.

    2013-09-01

    Emission inventories defining regional and global biogenic volatile organic compounds (VOC) emission strengths are needed to determine the impact of VOC on atmospheric chemistry (oxidative capacity) and physics (secondary organic aerosol formation and effects). The aim of this work was to contribute with measurements of tree species from the poorly described tropical vegetation in direct comparison with the quite well-investigated, highly heterogeneous emissions from Mediterranean vegetation. VOC emission from sixteen plant species from the Mediterranean area were compared with twelve plant species from different environments of the Amazon basin by an emission screening at leaf level using branch enclosures. Analysis of the volatile organics was performed online by a proton-transfer-reaction mass spectrometer (PTR-MS) and offline by collection on adsorbent tubes and subsequent gas chromatographic analysis. Isoprene was the most dominant compound emitted followed by monoterpenes, methanol and acetone. The average loss rates of VOC carbon in relation to the net CO2 assimilation were found below 4% and indicating normal unstressed plant behavior. Most of the Mediterranean species emitted a large variety of monoterpenes, whereas only five tropical species were identified as monoterpene emitters exhibiting a quite conservative emission pattern (α-pinene plants showed additional emissions of sesquiterpenes. In the case of Amazonian plants no sesquiterpenes were detected. However, missing of sesquiterpenes may also be due to a lack of sensitivity of the measuring systems. Furthermore, our screening activities cover only 1% of tree species of such tropical areas as estimated based on recent biodiversity reports. Methanol emissions, an indicator of growth, were found to be common in most of the tropical and Mediterranean species. A few species from both ecosystems showed acetone emissions. The observed heterogeneous emissions, including reactive VOC species which are not

  3. Leaf level emissions of volatile organic compounds (VOC from some Amazonian and Mediterranean plants

    Directory of Open Access Journals (Sweden)

    A. Bracho-Nunez

    2013-09-01

    Full Text Available Emission inventories defining regional and global biogenic volatile organic compounds (VOC emission strengths are needed to determine the impact of VOC on atmospheric chemistry (oxidative capacity and physics (secondary organic aerosol formation and effects. The aim of this work was to contribute with measurements of tree species from the poorly described tropical vegetation in direct comparison with the quite well-investigated, highly heterogeneous emissions from Mediterranean vegetation. VOC emission from sixteen plant species from the Mediterranean area were compared with twelve plant species from different environments of the Amazon basin by an emission screening at leaf level using branch enclosures. Analysis of the volatile organics was performed online by a proton-transfer-reaction mass spectrometer (PTR-MS and offline by collection on adsorbent tubes and subsequent gas chromatographic analysis. Isoprene was the most dominant compound emitted followed by monoterpenes, methanol and acetone. The average loss rates of VOC carbon in relation to the net CO2 assimilation were found below 4% and indicating normal unstressed plant behavior. Most of the Mediterranean species emitted a large variety of monoterpenes, whereas only five tropical species were identified as monoterpene emitters exhibiting a quite conservative emission pattern (α-pinene < limonene < sabinene < ß-pinene. Mediterranean plants showed additional emissions of sesquiterpenes. In the case of Amazonian plants no sesquiterpenes were detected. However, missing of sesquiterpenes may also be due to a lack of sensitivity of the measuring systems. Furthermore, our screening activities cover only 1% of tree species of such tropical areas as estimated based on recent biodiversity reports. Methanol emissions, an indicator of growth, were found to be common in most of the tropical and Mediterranean species. A few species from both ecosystems showed acetone emissions. The observed

  4. SOA Formation Potential of Emissions from Soil and Leaf Litter

    Science.gov (United States)

    Faiola, C. L.; Vanderschelden, G. S.; Wen, M.; Cobos, D. R.; Jobson, B. T.; VanReken, T. M.

    2013-12-01

    In the United States, emissions of volatile organic compounds (VOCs) from natural sources exceed all anthropogenic sources combined. VOCs participate in oxidative chemistry in the atmosphere and impact the concentrations of ozone and particulate material. The formation of secondary organic aerosol (SOA) is particularly complex and is frequently underestimated using state-of-the-art modeling techniques. We present findings that suggest emissions of important SOA precursors from soil and leaf litter are higher than current inventories would suggest, particularly under conditions typical of Fall and Spring. Soil and leaf litter samples were collected at Big Meadow Creek from the University of Idaho Experimental Forest. The dominant tree species in this area of the forest are ponderosa pine, Douglas-fir, and western larch. Samples were transported to the laboratory and housed within a 0.9 cubic meter Teflon dynamic chamber where VOC emissions were continuously monitored with a GC-FID-MS and PTR-MS. Aerosol was generated from soil and leaf litter emissions by pumping the emissions into a 7 cubic meter Teflon aerosol growth chamber where they were oxidized with ozone in the absence of light. The evolution of particle microphysical and chemical characteristics was monitored over the following eight hours. Particle size distribution and chemical composition were measured with a SMPS and HR-ToF-AMS respectively. Monoterpenes dominated the emission profile with emission rates up to 283 micrograms carbon per meter squared per hour. The dominant monoterpenes emitted were beta-pinene, alpha-pinene, and delta-3-carene in descending order. The composition of the SOA produced was similar to biogenic SOA formed from oxidation of ponderosa pine emissions and alpha-pinene. Measured soil/litter monoterpene emission rates were compared with modeled canopy emissions. Results suggest that during fall and spring when tree emissions are lower, monoterpene emissions within forests may be

  5. A DETAILED STUDY OF SPITZER-IRAC EMISSION IN HERBIG-HARO OBJECTS. I. MORPHOLOGY AND FLUX RATIOS OF SHOCKED EMISSION

    International Nuclear Information System (INIS)

    Takami, Michihiro; Karr, Jennifer L.; Chen, How-Huan; Lee, Hsu-Tai; Koh, Haegon

    2010-01-01

    We present a detailed analysis of Spitzer-IRAC images obtained toward six Herbig-Haro objects (HH 54/211/212, L 1157/1448, and BHR 71). Our analysis includes (1) comparisons of morphology between the four IRAC bands (3.6, 4.5, 5.8, and 8.0 μm) and H 2 1-0 S(1) at 2.12 μm for three out of six objects, (2) measurements of spectral energy distributions (SEDs) at selected positions, and (3) comparisons of these results with calculations of thermal H 2 emission at LTE (207 lines in four bands) and non-LTE (32-45 lines, depending on the particle for collisions). We show that the morphologies observed at 3.6 and 4.5 μm are similar to each other and to H 2 1-0 S(1). This is well explained by thermal H 2 emission at non-LTE if the dissociation rate is significantly larger than 0.002-0.02, allowing thermal collisions to be dominated by atomic hydrogen. In contrast, the 5.8 and 8.0 μm emission shows different morphologies from the others in some regions. This emission appears to be more enhanced at the wakes in bow shocks, or less enhanced in patchy structures in the jet. These tendencies are explained by the fact that thermal H 2 emission in the 5.8 and 8.0 μm band is enhanced in regions at lower densities and temperatures. Throughout, the observed similarities and differences in morphology between four bands and 1-0 S(1) are well explained by thermal H 2 emission. The observed SEDs are categorized into type-A, those in which the flux monotonically increases with wavelength, and type-B, those with excess emission at 4.5 μm. The type-A SEDs are explained by thermal H 2 emission, in particular with simple shock models with a power-law cooling function (Λ ∝ T s ). Our calculations suggest that the type-B SEDs require extra contaminating emission in the 4.5 μm band. The CO vibrational emission is the most promising candidate, and the other contaminants discussed to date (H I, [Fe II], fluorescent H 2 , and polycyclic aromatic hydrocarbon) are not likely to explain the

  6. Effect of compression ratio, nozzle opening pressure, engine load, and butanol addition on nanoparticle emissions from a non-road diesel engine.

    Science.gov (United States)

    Maurya, Rakesh Kumar; Saxena, Mohit Raj; Rai, Piyush; Bhardwaj, Aashish

    2018-05-01

    Currently, diesel engines are more preferred over gasoline engines due to their higher torque output and fuel economy. However, diesel engines confront major challenge of meeting the future stringent emission norms (especially soot particle emissions) while maintaining the same fuel economy. In this study, nanosize range soot particle emission characteristics of a stationary (non-road) diesel engine have been experimentally investigated. Experiments are conducted at a constant speed of 1500 rpm for three compression ratios and nozzle opening pressures at different engine loads. In-cylinder pressure history for 2000 consecutive engine cycles is recorded and averaged data is used for analysis of combustion characteristics. An electrical mobility-based fast particle sizer is used for analyzing particle size and mass distributions of engine exhaust particles at different test conditions. Soot particle distribution from 5 to 1000 nm was recorded. Results show that total particle concentration decreases with an increase in engine operating loads. Moreover, the addition of butanol in the diesel fuel leads to the reduction in soot particle concentration. Regression analysis was also conducted to derive a correlation between combustion parameters and particle number emissions for different compression ratios. Regression analysis shows a strong correlation between cylinder pressure-based combustion parameters and particle number emission.

  7. Increased Ratio of Electron Transport to Net Assimilation Rate Supports Elevated Isoprenoid Emission Rate in Eucalypts under Drought1[W][OPEN

    Science.gov (United States)

    Dani, Kaidala Ganesha Srikanta; Jamie, Ian McLeod; Prentice, Iain Colin; Atwell, Brian James

    2014-01-01

    Plants undergoing heat and low-CO2 stresses emit large amounts of volatile isoprenoids compared with those in stress-free conditions. One hypothesis posits that the balance between reducing power availability and its use in carbon assimilation determines constitutive isoprenoid emission rates in plants and potentially even their maximum emission capacity under brief periods of stress. To test this, we used abiotic stresses to manipulate the availability of reducing power. Specifically, we examined the effects of mild to severe drought on photosynthetic electron transport rate (ETR) and net carbon assimilation rate (NAR) and the relationship between estimated energy pools and constitutive volatile isoprenoid emission rates in two species of eucalypts: Eucalyptus occidentalis (drought tolerant) and Eucalyptus camaldulensis (drought sensitive). Isoprenoid emission rates were insensitive to mild drought, and the rates increased when the decline in NAR reached a certain species-specific threshold. ETR was sustained under drought and the ETR-NAR ratio increased, driving constitutive isoprenoid emission until severe drought caused carbon limitation of the methylerythritol phosphate pathway. The estimated residual reducing power unused for carbon assimilation, based on the energetic status model, significantly correlated with constitutive isoprenoid emission rates across gradients of drought (r2 > 0.8) and photorespiratory stress (r2 > 0.9). Carbon availability could critically limit emission rates under severe drought and photorespiratory stresses. Under most instances of moderate abiotic stress levels, increased isoprenoid emission rates compete with photorespiration for the residual reducing power not invested in carbon assimilation. A similar mechanism also explains the individual positive effects of low-CO2, heat, and drought stresses on isoprenoid emission. PMID:25139160

  8. Summit CO2 emission rates by the CO2/SO2 ratio method at Kīlauea Volcano, Hawaiʻi, during a period of sustained inflation

    Science.gov (United States)

    Hager, S.A.; Gerlach, T.M.; Wallace, P.J.

    2008-01-01

    The emission rate of carbon dioxide escaping from the summit of Kīlauea Volcano, Hawaiʻi, proved highly variable, averaging 4900 ± 2000 metric tons per day (t/d) in June–July 2003 during a period of summit inflation. These results were obtained by combining over 90 measurements of COSPEC-derived SO2emission rates with synchronous CO2/SO2 ratios of the volcanic gas plume along the summit COSPEC traverse. The results are lower than the CO2 emission rate of 8500 ± 300 t/d measured by the same method in 1995–1999 during a period of long-term summit deflation [Gerlach, T.M., McGee, K.A., Elias, T., Sutton, A.J. and Doukas, M.P., 2002. Carbon dioxide emission rate of Kīlauea Volcano: Implications for primary magma and the summit reservoir. Journal of Geophysical Research-Solid Earth, 107(B9): art. no.-2189.]. Analysis of the data indicates that the emission rates of the present study likely reflect changes in the magma supply rate and residence time in the summit reservoir. It is also likely that emission rates during the inflation period were heavily influenced by SO2 pulses emitted adjacent to the COSPEC traverse, which biased CO2/SO2 ratios towards low values that may be unrepresentative of the global summit gas plume. We conclude that the SO2 pulses are consequences of summit re-inflation under way since 2003 and that CO2 emission rates remain comparable to, but more variable than, those measured prior to re-inflation.

  9. Low-Computation Strategies for Extracting CO2 Emission Trends from Surface-Level Mixing Ratio Observations

    Science.gov (United States)

    Shusterman, A.; Kim, J.; Lieschke, K.; Newman, C.; Cohen, R. C.

    2017-12-01

    Global momentum is building for drastic, regulated reductions in greenhouse gas emissions over the coming decade. With this increasing regulation comes a clear need for increasingly sophisticated monitoring, reporting, and verification (MRV) strategies capable of enforcing and optimizing emissions-related policy, particularly as it applies to urban areas. Remote sensing and/or activity-based emission inventories can offer MRV insights for entire sectors or regions, but are not yet sophisticated enough to resolve unexpected trends in specific emitters. Urban surface monitors can offer the desired proximity to individual greenhouse gas sources, but due to the densely-packed nature of typical urban landscapes, surface observations are rarely representative of a single source. Most previous efforts to decompose these complex signals into their contributing emission processes have involved inverse atmospheric modeling techniques, which are computationally intensive and believed to depend heavily on poorly understood a priori estimates of error covariance. Here we present a number of transparent, low-computation approaches for extracting source-specific emissions estimates from signals with a variety of nearfield influences. Using observations from the first several years of the BErkeley Atmospheric CO2 Observation Network (BEACO2N), we demonstrate how to exploit strategic pairings of monitoring "nodes," anomalous wind conditions, and well-understood temporal variations to hone in on specific CO2 sources of interest. When evaluated against conventional, activity-based bottom-up emission inventories, these strategies are seen to generate quantitatively rigorous emission estimates. With continued application as the BEACO2N data set grows in time and space, these approaches offer a promising avenue for optimizing greenhouse gas mitigation strategies into the future.

  10. SDSS-IV MaNGA: the impact of diffuse ionized gas on emission-line ratios, interpretation of diagnostic diagrams and gas metallicity measurements

    Science.gov (United States)

    Zhang, Kai; Yan, Renbin; Bundy, Kevin; Bershady, Matthew; Haffner, L. Matthew; Walterbos, René; Maiolino, Roberto; Tremonti, Christy; Thomas, Daniel; Drory, Niv; Jones, Amy; Belfiore, Francesco; Sánchez, Sebastian F.; Diamond-Stanic, Aleksandar M.; Bizyaev, Dmitry; Nitschelm, Christian; Andrews, Brett; Brinkmann, Jon; Brownstein, Joel R.; Cheung, Edmond; Li, Cheng; Law, David R.; Roman Lopes, Alexandre; Oravetz, Daniel; Pan, Kaike; Storchi Bergmann, Thaisa; Simmons, Audrey

    2017-04-01

    Diffuse ionized gas (DIG) is prevalent in star-forming galaxies. Using a sample of 365 nearly face-on star-forming galaxies observed by Mapping Nearby Galaxies at APO, we demonstrate how DIG in star-forming galaxies impacts the measurements of emission-line ratios, hence the interpretation of diagnostic diagrams and gas-phase metallicity measurements. At fixed metallicity, DIG-dominated low ΣHα regions display enhanced [S II]/Hα, [N II]/Hα, [O II]/Hβ and [O I]/Hα. The gradients in these line ratios are determined by metallicity gradients and ΣHα. In line ratio diagnostic diagrams, contamination by DIG moves H II regions towards composite or low-ionization nuclear emission-line region (LI(N)ER)-like regions. A harder ionizing spectrum is needed to explain DIG line ratios. Leaky H II region models can only shift line ratios slightly relative to H II region models, and thus fail to explain the composite/LI(N)ER line ratios displayed by DIG. Our result favours ionization by evolved stars as a major ionization source for DIG with LI(N)ER-like emission. DIG can significantly bias the measurement of gas metallicity and metallicity gradients derived using strong-line methods. Metallicities derived using N2O2 are optimal because they exhibit the smallest bias and error. Using O3N2, R23, N2 = [N II]/Hα and N2S2Hα to derive metallicities introduces bias in the derived metallicity gradients as large as the gradient itself. The strong-line method of Blanc et al. (IZI hereafter) cannot be applied to DIG to get an accurate metallicity because it currently contains only H II region models that fail to describe the DIG.

  11. Sea-to-air flux of dimethyl sulfide in the South and North Pacific Ocean as measured by proton transfer reaction-mass spectrometry coupled with the gradient flux technique

    Science.gov (United States)

    Omori, Yuko; Tanimoto, Hiroshi; Inomata, Satoshi; Ikeda, Kohei; Iwata, Toru; Kameyama, Sohiko; Uematsu, Mitsuo; Gamo, Toshitaka; Ogawa, Hiroshi; Furuya, Ken

    2017-07-01

    Exchange of dimethyl sulfide (DMS) between the surface ocean and the lower atmosphere was examined by using proton transfer reaction-mass spectrometry coupled with the gradient flux (PTR-MS/GF) system. We deployed the PTR-MS/GF system and observed vertical gradients of atmospheric DMS just above the sea surface in the subtropical and transitional South Pacific Ocean and the subarctic North Pacific Ocean. In total, we obtained 370 in situ profiles, and of these we used 46 data sets to calculate the sea-to-air flux of DMS. The DMS flux determined was in the range from 1.9 to 31 μmol m-2 d-1 and increased with wind speed and biological activity, in reasonable accordance with previous observations in the open ocean. The gas transfer velocity of DMS derived from the PTR-MS/GF measurements was similar to either that of DMS determined by the eddy covariance technique or that of insoluble gases derived from the dual tracer experiments, depending on the observation sites located in different geographic regions. When atmospheric conditions were strongly stable during the daytime in the subtropical ocean, the PTR-MS/GF observations captured a daytime versus nighttime difference in DMS mixing ratios in the surface air overlying the ocean surface. The difference was mainly due to the sea-to-air DMS emissions and stable atmospheric conditions, thus affecting the gradient of DMS. This indicates that the DMS gradient is strongly controlled by diurnal variations in the vertical structure of the lower atmosphere above the ocean surface.

  12. The impact of energy production on the atmosphere: Laboratory and field studies of emissions from oil and gas production and their chemical transformation

    Science.gov (United States)

    Li, Rui

    Over the past decades, the rapid development of energy production in the U.S. has led to significant changes in atmospheric emissions and transformation of trace gas and particles, which are still very uncertain and poorly understood. Through laboratory, modeling and field experiments we hope to better understand the trace gas emission and their contribution to secondary organic aerosols (SOA) formation in the oil and natural gas (O&NG) operations. A fast time-response Oxidation Flow Reactor (OFR) is used for the study of SOA formation from oil vapors. The radical chemistry and quantification of OH exposure (OHexp) in the reactor under various conditions were investigated using a photochemical kinetic model. An OHexp estimation equation derived from the model was shown to agree with measurements in several field campaigns. This work further establishes the usefulness of such reactors in atmospheric studies. Motivated from the SOA observations of Gulf of Mexico oil spill, the SOA formation from organic compounds of different volatility in the oil vapors was studied in the laboratory using OFR. We use the evaporation time dependence on volatility of the precursors to quantify their contribution to total SOA formation. This study shows (1) organic compounds of intermediate volatility contribute the large majority of SOA mass formed, (2) the mass spectral signature of SOA shows good agreement with that of ambient SOA formed during oil spill. These results in O&NG operations, the air toxic hydrogen sulfide (H 2S) can be released at wellheads, separation and storage tanks. Here, quantitative, fast time-response measurements of H2S using Proton-Transfer-Reaction Mass-Spectrometry (PTR-MS) instruments in an O&NG field are presented. A laboratory calibration study was performed to measure the humidity dependent sensitivities of H2S. The close correlation between H2S and CH4 and significant H2S levels downwind of storage tanks suggest that H2S emissions associated with O

  13. Volcanic SO2 and SiF4 visualization using 2-D thermal emission spectroscopy – Part 1: Slant-columns and their ratios

    Directory of Open Access Journals (Sweden)

    M. Grutter

    2012-02-01

    Full Text Available The composition and emission rates of volcanic gas plumes provide insight of the geologic internal activity, atmospheric chemistry, aerosol formation and radiative processes around it. Observations are necessary for public security and the aviation industry. Ground-based thermal emission infrared spectroscopy, which uses the radiation of the volcanic gas itself, allows for continuously monitoring during day and night from a safe distance. We present measurements on Popocatépetl volcano based on thermal emission spectroscopy during different campaigns between 2006–2009 using a Scanning Infrared Gas Imaging System (SIGIS. The experimental set-up, measurement geometries and analytical algorithms are described. The equipment was operated from a safe distance of 12 km from the volcano at two different spectral resolutions: 0.5 and 4 cm−1. The 2-dimensional scanning capability of the instrument allows for an on-line visualization of the volcanic SO2 plume and its animation. SiF4 was also identified in the infrared spectra recorded at both resolutions. The SiF4/SO2 molecular ratio can be calculated from each image and used as a highly useful parameter to follow changes in volcanic activity. A small Vulcanian eruption was monitored during the night of 16 to 17 November 2008 and strong ash emission together with a pronounced SO2 cloud was registered around 01:00 a.m. LST (Local Standard Time. Enhanced SiF4/SO2 ratios were observed before and after the eruption. A validation of the results from thermal emission measurements with those from absorption spectra of the moon taken at the same time, as well as an error analysis, are presented. The inferred propagation speed from sequential images is used in a subsequent paper (Part 2 to calculate the emission rates at different distances from the crater.

  14. Effect of digestibility of grass-clover silage and concentrate to forage ratio on methane emission from dairy cows

    DEFF Research Database (Denmark)

    Hellwing, Anne Louise Frydendahl; Weisbjerg, Martin Riis

    and D, respectively. TMR forage DM consisted of 2/3 of one of the respective grass-clover silages and 1/3 maize silage, and concentrate (soya meal and wheat) proportion of DM was 20% (low) or 50% (high). Methane emissions from the cows were measured 20-22 hours in one of four chambers working after...

  15. Two-dimensional imaging of edge plasma electron density and temperature by the passive helium emission ratio technique in TJ-II

    International Nuclear Information System (INIS)

    De la Cal, E; Guasp, J

    2011-01-01

    An intensified visible camera looks tangentially at a poloidal limiter where helium recycles, acting as a wide neutral source, and the atomic line emission due to plasma excitation becomes strongly localized there. It includes a bifurcated coherent bundle, each end with a different interference filter to select helium atomic lines, so that two simultaneous filtered images are captured in one single frame. The object of the proposed technique is to apply the well-known helium-beam line-ratio technique to obtain from selected filtered images the two-dimensional (2D) edge plasma n e and T e . The code EIRENE was used to demonstrate that the helium emission from recycling neutrals dominates the emission for the lines of view passing close above the limiter. Since these chords are nearly parallel to magnetic field lines in the emission region, the images can be approximated to poloidal cuts of the plasma emission within the tolerances discussed in the paper. The absolute radial profiles of T e and n e obtained with the method presented here were checked in the TJ-II stellarator to be in relatively good agreement with other diagnostics within a wide range of plasma parameters for both ECRH and NBI plasmas. The method is finally used to get 2D images of edge plasma T e and n e .

  16. Impact Parameter Dependence of the Double Neutron/Proton Ratio of Nucleon Emissions in Isotopic Reaction Systems

    International Nuclear Information System (INIS)

    Xun-Chao, Zhang; Gao-Chan, Yong; Bao-An, Li; Lie-Wen, Chen

    2009-01-01

    Within the transport model IBUU04, we investigate the double neutron/proton ratio of free nucleons taken from two reaction systems using two Sn isotopes at a beam energy of 50 MeV/nucleon and with impact parameters 2 fm, 4 fm and 8 fm, respectively. It is found that the double neutron/proton ratio from peripheral collisions is more sensitive to the density dependence of the symmetry energy than those from mid-central and central collisions. (nuclear physics)

  17. A study on correlating reduction in Poisson's ratio with transverse crack and delamination through acoustic emission signals

    OpenAIRE

    Yılmaz, Çağatay; Yilmaz, Cagatay; Yıldız, Mehmet; Yildiz, Mehmet

    2017-01-01

    During the uniaxial loading of fiber reinforced polymer (FRP) composites, Poisson's ratio (νxy), which is a constant elastic property for isotropic materials, decreases significantly. Micro-damage created within FRP composites as a result of an applied stress causes this decrease. As the level of micro-damage increases, a greater level of reduction in Poisson's ratio occurs. FRP composites, in general, show three main micro-damage types under uniaxial tensile loading, namely, transverse crack...

  18. Contrasting winter and summer VOC mixing ratios at a forest site in the Western Mediterranean Basin: the effect of local biogenic emissions

    Directory of Open Access Journals (Sweden)

    R. Seco

    2011-12-01

    Full Text Available Atmospheric volatile organic compounds (VOCs are involved in ozone and aerosol generation, thus having implications for air quality and climate. VOCs and their emissions by vegetation also have important ecological roles as they can protect plants from stresses and act as communication cues between plants and between plants and animals. In spite of these key environmental and biological roles, the reports on seasonal and daily VOC mixing ratios in the literature for Mediterranean natural environments are scarce.

    We conducted seasonal (winter and summer measurements of VOC mixing ratios in an elevated (720 m a.s.l. holm oak Mediterranean forest site near the metropolitan area of Barcelona (NE Iberian Peninsula. Methanol was the most abundant compound among all the VOCs measured in both seasons. While aromatic VOCs showed almost no seasonal variability, short-chain oxygenated VOCs presented higher mixing ratios in summer, presumably due to greater emission by vegetation and increased photochemistry, both enhanced by the high temperatures and solar radiation in summer. Isoprenoid VOCs showed the biggest seasonal change in mixing ratios: they increased by one order of magnitude in summer, as a result of the vegetation's greater physiological activity and emission rates. The maximum diurnal concentrations of ozone increased in summer too, most likely due to more intense photochemical activity and the higher levels of VOCs in the air.

    The daily variation of VOC mixing ratios was mainly governed by the wind regime of the mountain, as the majority of the VOC species analyzed followed a very similar diel cycle. Mountain and sea breezes that develop after sunrise advect polluted air masses to the mountain. These polluted air masses had previously passed over the urban and industrial areas surrounding the Barcelona metropolitan area, where they were enriched in NOx and in VOCs of biotic and abiotic origin. Moreover, these

  19. Contrasting winter and summer VOC mixing ratios at a forest site in the Western Mediterranean Basin: the effect of local biogenic emissions

    Science.gov (United States)

    Seco, R.; Peñuelas, J.; Filella, I.; Llusià, J.; Molowny-Horas, R.; Schallhart, S.; Metzger, A.; Müller, M.; Hansel, A.

    2011-12-01

    Atmospheric volatile organic compounds (VOCs) are involved in ozone and aerosol generation, thus having implications for air quality and climate. VOCs and their emissions by vegetation also have important ecological roles as they can protect plants from stresses and act as communication cues between plants and between plants and animals. In spite of these key environmental and biological roles, the reports on seasonal and daily VOC mixing ratios in the literature for Mediterranean natural environments are scarce. We conducted seasonal (winter and summer) measurements of VOC mixing ratios in an elevated (720 m a.s.l.) holm oak Mediterranean forest site near the metropolitan area of Barcelona (NE Iberian Peninsula). Methanol was the most abundant compound among all the VOCs measured in both seasons. While aromatic VOCs showed almost no seasonal variability, short-chain oxygenated VOCs presented higher mixing ratios in summer, presumably due to greater emission by vegetation and increased photochemistry, both enhanced by the high temperatures and solar radiation in summer. Isoprenoid VOCs showed the biggest seasonal change in mixing ratios: they increased by one order of magnitude in summer, as a result of the vegetation's greater physiological activity and emission rates. The maximum diurnal concentrations of ozone increased in summer too, most likely due to more intense photochemical activity and the higher levels of VOCs in the air. The daily variation of VOC mixing ratios was mainly governed by the wind regime of the mountain, as the majority of the VOC species analyzed followed a very similar diel cycle. Mountain and sea breezes that develop after sunrise advect polluted air masses to the mountain. These polluted air masses had previously passed over the urban and industrial areas surrounding the Barcelona metropolitan area, where they were enriched in NOx and in VOCs of biotic and abiotic origin. Moreover, these polluted air masses receive additional biogenic

  20. Neutron to proton ratios of quasiprojectile and midrapidity emission in the 58Ni+58Ni reaction at 52 MeV/nucleon

    International Nuclear Information System (INIS)

    Theriault, D.; Vallee, A.; Gingras, L.; Larochelle, Y.; Roy, R.; April, A.; Beaulieu, L.; Grenier, F.; Lemieux, F.; Moisan, J.; St-Pierre, C.; Turbide, S.; Samri, M.; Borderie, B.; Rivet, M. F.; Bougault, R.; Colin, J.; Cussol, D.; Durand, D.; Lecolley, J.F.

    2005-01-01

    By combining data from a charged particle 58 Ni+ 58 Ni experiment at 52 MeV/nucleon with an 36 Ar+ 58 Ni experiment at 50 MeV/nucleon for which free neutrons have been detected, an increase in the neutron to proton ratio of the whole nuclear material at midrapidity has been experimentally observed in the reaction 58 Ni+ 58 Ni at 52 MeV/nucleon. The neutron-to-proton ratio of the quasi-projectile emission is analyzed for the same reactions and is seen to decrease below the ratio of the initial system. Those observations suggest that an asymmetric exchange of neutrons and protons between the quasiprojectile and the midrapidity region exists

  1. Storm/Quiet Ratio Comparisons Between TIMED/SABER NO (sup +)(v) Volume Emission Rates and Incoherent Scatter Radar Electron Densities at E-Region Altitudes

    Science.gov (United States)

    Fernandez, J. R.; Mertens, C. J.; Bilitza, D.; Xu, X.; Russell, J. M., III; Mlynczak, M. G.

    2009-01-01

    Broadband infrared limb emission at 4.3 microns is measured by the TIMED/SABER instrument. At night, these emission observations at E-region altitudes are used to derive the so called NO+(v) Volume Emission Rate (VER). NO+(v) VER can be derived by removing the background CO2(v3) 4.3 microns radiance contribution using SABER-based non-LTE radiation transfer models, and by performing a standard Abel inversion on the residual radiance. SABER observations show that NO+(v) VER is significantly enhanced during magnetic storms in accordance with increased ionization of the neutral atmosphere by auroral electron precipitation, followed by vibrational excitation of NO+ (i.e., NO+(v)) from fast exothermic ion-neutral reactions, and prompt infrared emission at 4.3 m. Due to charge neutrality, the NO+(v) VER enhancements are highly correlated with electron density enhancements, as observed for example by Incoherent Scatter Radar (ISR). In order to characterize the response of the storm-time E-region from both SABER and ISR measurements, a Storm/Quiet ratio (SQR) quantity is defined as a function of altitude. For SABER, the SQR is the ratio of the storm-to-quiet NO+(v) VER. SQR is the storm-to-quiet ratio of electron densities for ISR. In this work, we compare SABER and ISR SQR values between 100 to 120 km. Results indicate good agreement between these measurements. SQR values are intended to be used as a correction factor to be included in an empirical storm-time correction to the International Reference Ionosphere model at E-region altitudes.

  2. Effective tuning of the ratio of red to green emission of Ho"3"+ ions in single LiLuF_4 microparticle via codoping Ce"3"+ ions

    International Nuclear Information System (INIS)

    Gao, Wei; Dong, Jun; Liu, Jihong; Yan, Xuewen

    2016-01-01

    Yb"3"+/Ho"3"+ codoped LiLuF_4 microparticles have been successfully prepared via a facile hydrothermal method. The crystal phase and morphology of LiLuF_4 microparticles were inspected by x-ray diffraction and scanning electron microscope, respectively. The upconversion emission of single LiLuF_4: Yb"3"+/Ho"3"+ microparticle was carefully studied by a confocal microscopy setup under NIR 980 nm excitation. With the increase of Ce"3"+ ion concentrations of 12%, the ratio of red to green emission of the Ho"3"+ ions of single LiLuF_4 microparticle was boosted about 17-fold, and the output colors were tuned from green to red, which is due to the two efficient cross-relaxation between Ho"3"+ and Ce"3"+ ions enhances the red and suppresses the green in the emission processes. To investigate the optical properties of the single microparticle or nanoparticle through the confocal microscopy setup can effectively avoid the influence of surrounding particle or environment, and could provide more precise information for better exploring the emission mechanisms of rare earth ions. The tunable upconversion emission of Ho"3"+ in single LiLuF_4 microparticle in this work will have great potential applications in the micro optoelectronic devices and color display applications. - Highlights: • The optical properties of the single LiLuF4: Yb3+/Ho3+/Ce3+ microparticle were studied. • The output colors of single LiLuF4 microparticle were tuned from green to red. • The upconversion mechanisms between Ho3+ and Ce3+ ions were discussed based on emission spectrum.

  3. Theoretical calculations of L alpha one x-ray emission intensity ratios for uranium in various matrices: a comparison with experimental values

    International Nuclear Information System (INIS)

    Anderson, L.D.

    1976-01-01

    The U L/sub α1/ x-ray emission intensity ratios (I/sub lambda/sub L//I sub lambda/sub L/, sub 100 percent/sub UO 2 /) in various matrices were calculated using the fundamental parameters formula of Criss and Birks and mass absorption coefficients calculated from a formula developed by Dewey. The use of the intensity ratio made it unnecessary to know the fluorescence yield for the U L/sub III/ level, the probability of emission of the U L/sub α1/ line, and the jump ratios for the three absorption edges of uranium. Also, since an intensity ratio was used, the results are independent of the x-ray tube current and the spectral distribution of the x-ray tube. A method is presented to calculate the intensity ratios for x-ray tube voltages other than the value (45 kV) used in the calculations. The theoretical results are calculated and compared with the experimental results obtained for 141 matrices. Difficulties due to oxidation of some of the metal powders used in the sample preparation, to small concentrations of uranium, and to an excessively large number of elements present in some of the samples resulted in the invalidation of the experimental results for 91 of the matrices. For the remaining 50 matrices, the theoretical and experimental values agreed to within +-5 percent relative error for 36 matrices; to within +-5 percent to +- 10 percent for 7 matrices; to within +-10 percent to +-20 percent for 6 matrices; and was greater than +-20 percent for 1 matrix

  4. PTR-MS Characterization of VOCs Associated with Commercial Aromatic Bakery Yeasts of Wine and Beer Origin

    Directory of Open Access Journals (Sweden)

    Vittorio Capozzi

    2016-04-01

    Full Text Available In light of the increasing attention towards “green” solutions to improve food quality, the use of aromatic-enhancing microorganisms offers the advantage to be a natural and sustainable solution that did not negatively influence the list of ingredients. In this study, we characterize, for the first time, volatile organic compounds (VOCs associated with aromatic bakery yeasts. Three commercial bakery starter cultures, respectively formulated with three Saccharomyces cerevisiae strains, isolated from white wine, red wine, and beer, were monitored by a proton-transfer-reaction time-of-flight mass spectrometer (PTR-ToF-MS, a direct injection analytical technique for detecting volatile organic compounds with high sensitivity (VOCs. Two ethanol-related peaks (m/z 65.059 and 75.080 described qualitative differences in fermentative performances. The release of compounds associated to the peaks at m/z 89.059, m/z 103.075, and m/z 117.093, tentatively identified as acetoin and esters, are coherent with claimed flavor properties of the investigated strains. We propose these mass peaks and their related fragments as biomarkers to optimize the aromatic performances of commercial preparations and for the rapid massive screening of yeast collections.

  5. Desiccant wheels as gas-phase absorption (GPA) air cleaners: evaluation by PTR-MS and sensory assessment

    DEFF Research Database (Denmark)

    Fang, Lei; Zhang, G.; Wisthaler, A.

    2008-01-01

    Two experiments were conducted to investigate the use of the co-sorption effect of a desiccant wheel for improving indoor air quality. One experiment was conducted in a climate chamber to investigate the co-sorption effect of a desiccant wheel on the chemical removal of indoor air pollutants......; another experiment was conducted in an office room to investigate the resulting effect on perceived air quality. A dehumidifier with a silica-gel desiccant wheel was installed in the ventilation system of the test chamber and office room to treat the recirculation airflow. Human subjects, flooring...

  6. Response surface methodology based optimization of diesel–n-butanol –cotton oil ternary blend ratios to improve engine performance and exhaust emission characteristics

    International Nuclear Information System (INIS)

    Atmanlı, Alpaslan; Yüksel, Bedri; İleri, Erol; Deniz Karaoglan, A.

    2015-01-01

    Highlights: • RSM based optimization for optimum blend ratio of diesel fuel, n-butanol and cotton oil was done. • 65.5 vol.% diesel fuel, 23.1 vol.% n-butanol and 11.4 vol.% cotton oil (DnBC) was determined. • DnBC decreased brake torque, brake power, BTE and BMEP, while increased BSFC. • DnBC decreased NO x , CO and HC emissions. - Abstract: Many studies declare that 20% biodiesel is the optimum concentration for biodiesel–diesel fuel blends to improve performance. The present work focuses on finding diesel fuel, n-butanol, and cotton oil optimum blend ratios for diesel engine applications by using the response surface method (RSM). Experimental test fuels were prepared by choosing 7 different concentrations, where phase decomposition did not occur in the phase diagram of −10 °C. Experiments were carried out at full load conditions and the constant speed (2200 rpm) of maximum brake torque to determine engine performance and emission parameters. According to the test results of the engine, optimization was done by using RSM considering engine performance and exhaust emissions parameters, to identify the rates of concentrations of components in the optimum blend of three. Confirmation tests were employed to compare the output values of concentrations that were identified by optimization. The real experiment results and the R 2 actual values that show the relation between the outputs from the optimizations and real experiments were determined in high accordance. The optimum component concentration was determined as 65.5 vol.% diesel, 23.1 vol.% n-butanol and 11.4 vol.% cotton oil (DnBC). According to engine performance tests brake torque, brake power, BTE and BMEP of DnBC decreased while BSFC increased compared to those of diesel fuel. NO x , CO and HC emissions of DnBC drastically decreased as 11.33%, 45.17% and 81.45%, respectively

  7. The relationships between termite mound CH4/CO2 emissions and internal concentration ratios are species specific

    Directory of Open Access Journals (Sweden)

    H. Jamali

    2013-04-01

    Full Text Available We investigated the relative importance of CH4 and CO2 fluxes from soil and termite mounds at four different sites in the tropical savannas of northern Australia near Darwin and assessed different methods to indirectly predict CH4 fluxes based on CO2 fluxes and internal gas concentrations. The annual flux from termite mounds and surrounding soil was dominated by CO2 with large variations among sites. On a carbon dioxide equivalent (CO2-e basis, annual CH4 flux estimates from termite mounds were 5- to 46-fold smaller than the concurrent annual CO2 flux estimates. Differences between annual soil CO2 and soil CH4 (CO2-e fluxes were even greater, soil CO2 fluxes being almost three orders of magnitude greater than soil CH4 (CO2-e fluxes at site. The contribution of CH4 and CO2 emissions from termite mounds to the total CH4 and CO2 emissions from termite mounds and soil in CO2-e was less than 1%. There were significant relationships between mound CH4 flux and mound CO2 flux, enabling the prediction of CH4 flux from measured CO2 flux; however, these relationships were clearly termite species specific. We also observed significant relationships between mound flux and gas concentration inside mound, for both CH4 and CO2, and for all termite species, thereby enabling the prediction of flux from measured mound internal gas concentration. However, these relationships were also termite species specific. Using the relationship between mound internal gas concentration and flux from one species to predict mound fluxes from other termite species (as has been done in the past would result in errors of more than 5-fold for mound CH4 flux and 3-fold for mound CO2 flux. This study highlights that CO2 fluxes from termite mounds are generally more than one order of magnitude greater than CH4 fluxes. There are species-specific relationships between CH4 and CO2 fluxes from a mound, and between the inside mound concentration of a gas and the mound flux emission of the

  8. The relationships between termite mound CH4/CO2 emissions and internal concentration ratios are species specific

    Science.gov (United States)

    Jamali, H.; Livesley, S. J.; Hutley, L. B.; Fest, B.; Arndt, S. K.

    2013-04-01

    We investigated the relative importance of CH4 and CO2 fluxes from soil and termite mounds at four different sites in the tropical savannas of northern Australia near Darwin and assessed different methods to indirectly predict CH4 fluxes based on CO2 fluxes and internal gas concentrations. The annual flux from termite mounds and surrounding soil was dominated by CO2 with large variations among sites. On a carbon dioxide equivalent (CO2-e) basis, annual CH4 flux estimates from termite mounds were 5- to 46-fold smaller than the concurrent annual CO2 flux estimates. Differences between annual soil CO2 and soil CH4 (CO2-e) fluxes were even greater, soil CO2 fluxes being almost three orders of magnitude greater than soil CH4 (CO2-e) fluxes at site. The contribution of CH4 and CO2 emissions from termite mounds to the total CH4 and CO2 emissions from termite mounds and soil in CO2-e was less than 1%. There were significant relationships between mound CH4 flux and mound CO2 flux, enabling the prediction of CH4 flux from measured CO2 flux; however, these relationships were clearly termite species specific. We also observed significant relationships between mound flux and gas concentration inside mound, for both CH4 and CO2, and for all termite species, thereby enabling the prediction of flux from measured mound internal gas concentration. However, these relationships were also termite species specific. Using the relationship between mound internal gas concentration and flux from one species to predict mound fluxes from other termite species (as has been done in the past) would result in errors of more than 5-fold for mound CH4 flux and 3-fold for mound CO2 flux. This study highlights that CO2 fluxes from termite mounds are generally more than one order of magnitude greater than CH4 fluxes. There are species-specific relationships between CH4 and CO2 fluxes from a mound, and between the inside mound concentration of a gas and the mound flux emission of the same gas, but

  9. Synthesis and field emission characteristics of carbon nanocoils with a high aspect ratio supported by copper micro-tips

    International Nuclear Information System (INIS)

    Sung, Woo Yong; Ok, Jong Girl; Kim, Wal Jun; Lee, Seung Min; Yeon, Soon Chang; Lee, Ho Young; Kim, Yong Hyup

    2007-01-01

    Carbon nanocoils (CNCs) were synthesized via thermal chemical vapour deposition (CVD) with C 2 H 2 and NH 3 gases at 600 deg. C. A Ni catalyst was placed upon the copper micro-tip structures that were fabricated on a silicon substrate. Our CNCs had a long rope shape with a length not exceeding 100 μm and a nanoscale diameter. The copper micro-tips were formed through high current pulse electroplating, which played a significant role in characterizing our CNCs. The CNCs grown on the copper micro-tips showed outstanding field emission performance and long-term stability. Their turn-on field, defined as that at a current density of 10 μA cm -2 , was 1.30 V μm -1 and the maximum current density reached 11.17 mA cm -2 at an electric field of 2.39 V μm -1

  10. Birth to death analysis of the energy payback ratio and CO2 gas emission rates from coal, fission, wind, and DT-fusion electrical power plants

    International Nuclear Information System (INIS)

    White, Scott W.; Kulcinski, Gerald L.

    2000-01-01

    The amount of electrical energy produced over the lifetime of coal, LWR fission, UP fusion, and wind power plants is compared to the total amount of energy required to procure the fuel, build, operate, and decommission the power plants. The energy payback ratio varies from a low of 11 for coal plants to a high of 27 for DT-fusion plants. The magnitude of the energy investment and the source of the various energy inputs determine the CO 2 emission factor. This number varies from a low of 9 to a high of 974 tonnes of CO 2 per GW e h for DT-fusion and coal plants, respectively

  11. Molecular interaction between Methylobacterium extorquens and seedlings: growth promotion, methanol consumption, and localization of the methanol emission site.

    Science.gov (United States)

    Abanda-Nkpwatt, Daniel; Müsch, Martina; Tschiersch, Jochen; Boettner, Mewes; Schwab, Wilfried

    2006-01-01

    Four Methylobacterium extorquens strains were isolated from strawberry (Fragaria x ananassa cv. Elsanta) leaves, and one strain, called ME4, was tested for its ability to promote the growth of various plant seedlings. Seedling weight and shoot length of Nicotiana tabacum, Lycopersicon esculentum, Sinapis alba, and Fragaria vesca increased significantly in the presence of the pink-pigmented facultative methylotroph (PPFM), but the germination behaviour of seeds from six other plants was not affected. The cell-free supernatant of the bacterial culture stimulated germination, suggesting the production of a growth-promoting agent by the methylotroph. Methanol emitted from N. tabacum seedlings, as determined by proton-transfer-reaction mass spectrometry (PTR-MS), ranged from 0.4 to 0.7 ppbv (parts per billion by volume), while significantly lower levels (0.005 to 0.01 ppbv) of the volatile alcohol were measured when the seedlings were co-cultivated with M. extorquens ME4, demonstrating the consumption of the gaseous methanol by the bacteria. Additionally, by using cells of the methylotrophic yeast Pichia pastoris transformed with the pPICHS/GFP vector harbouring a methanol-sensitive promoter in combination with the green fluorescence protein (GFP) reporter gene, stomata were identified as the main source of the methanol emission on tobacco cotyledons. Methylobacterium extorquens strains can nourish themselves using the methanol released by the stomata and release an agent promoting the growth of the seedlings of some crop plants.

  12. SHOCKED POSTSTARBUST GALAXY SURVEY. I. CANDIDATE POST-STARBUST GALAXIES WITH EMISSION LINE RATIOS CONSISTENT WITH SHOCKS

    Energy Technology Data Exchange (ETDEWEB)

    Alatalo, Katherine; Rich, Jeffrey A. [Observatories of the Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Cales, Sabrina L. [Yale Center for Astronomy and Astrophysics, Physics Department, Yale University, New Haven, CT 06511 (United States); Appleton, Philip N.; Lanz, Lauranne [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States); Kewley, Lisa J.; Medling, Anne M. [Research School of Astronomy and Astrophysics, Australian National University, Cotter Road, Weston ACT 2611 (Australia); Lacy, Mark; Nyland, Kristina, E-mail: kalatalo@carnegiescience.edu [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States)

    2016-06-01

    There are many mechanisms by which galaxies can transform from blue, star-forming spirals, to red, quiescent early-type galaxies, but our current census of them does not form a complete picture. Recent observations of nearby case studies have identified a population of galaxies that quench “quietly.” Traditional poststarburst searches seem to catch galaxies only after they have quenched and transformed, and thus miss any objects with additional ionization mechanisms exciting the remaining gas. The Shocked POststarburst Galaxy Survey (SPOGS) aims to identify transforming galaxies, in which the nebular lines are excited via shocks instead of through star formation processes. Utilizing the Oh-Sarzi-Schawinski-Yi (OSSY) measurements on the Sloan Digital Sky Survey Data Release 7 catalog, we applied Balmer absorption and shock boundary criteria to identify 1067 SPOG candidates (SPOGs*) within z = 0.2. SPOGs* represent 0.2% of the OSSY sample galaxies that exceed the continuum signal-to-noise cut (and 0.7% of the emission line galaxy sample). SPOGs* colors suggest that they are in an earlier phase of transition than OSSY galaxies that meet an “E+A” selection. SPOGs* have a 13% 1.4 GHz detection rate from the Faint Images of the Radio Sky at Twenty Centimeters Survey, higher than most other subsamples, and comparable only to low-ionization nuclear emission line region hosts, suggestive of the presence of active galactic nuclei (AGNs). SPOGs* also have stronger Na i D absorption than predicted from the stellar population, suggestive of cool gas being driven out in galactic winds. It appears that SPOGs* represent an earlier phase in galaxy transformation than traditionally selected poststarburst galaxies, and that a large proportion of SPOGs* also have properties consistent with disruption of their interstellar media, a key component to galaxy transformation. It is likely that many of the known pathways to transformation undergo a SPOG phase. Studying this sample of

  13. Experimental evaluation of the effect of compression ratio on performance and emission of SI engine fuelled with gasoline and n-butanol blend at different loads

    Directory of Open Access Journals (Sweden)

    Rinu Thomas

    2016-09-01

    Full Text Available Never ending demand for efficient and less polluting engines have always inspired newer technologies. Extensive study has been done on variable compression ratio, a promising in-cylinder technology, in the recent past. The present work is an experimental investigation to examine the variation of different parameters such as brake thermal efficiency, exhaust gas temperature and emissions with respect to change in compression ratio in a single-cylinder carbureted SI engine at different loads with two different fuels. Experiments were conducted at three different compression ratios (CR = 7:1, 8.5:1 and 10:1. The fuels used in this study are pure gasoline and 20% n-butanol blend (B20 in gasoline. The results showed that brake thermal efficiency increases with CR at all loads. Further, the experimental results showed the scope of improving the part-load efficiency of SI engine by adopting the concept of variable compression ratio (VCR technology, especially when fuels with better anti-knock characteristics are used. The uncertainty analysis of the experiments based on the specifications of the equipment used is also tabulated.

  14. The relationship between termite mound CH4/CO2 emissions and internal concentration ratios are species specific

    Science.gov (United States)

    Jamali, H.; Livesley, S. J.; Hutley, L. B.; Fest, B.; Arndt, S. K.

    2012-12-01

    1. We investigated the relative importance of CH4 and CO2 fluxes from soil and termite mounds at four different sites in the tropical savannas of Northern Australia near Darwin and assessed different methods to indirectly predict CH4 fluxes based on CO2 fluxes and internal gas concentrations. 2. The annual flux from termite mounds and surrounding soil was dominated by CO2 with large variations among sites. On a CO2-e basis, annual CH4 flux estimates from termite mounds were 5- to 46-fold smaller than the concurrent annual CO2 flux estimates. Differences between annual soil CO2 and soil CH4 (CO2-e) fluxes were even greater, soil CO2 fluxes being almost three orders of magnitude greater than soil CH4 (CO2-e) fluxes at site. 3. There were significant relationships between mound CH4 flux and mound CO2 flux, enabling the prediction of CH4 flux from measured CO2 flux, however, these relationships were clearly termite species specific. 4. We also observed significant relationships between mound flux and gas concentration inside mound, for both CH4 and CO2, and for all termite species, thereby enabling the prediction of flux from measured mound internal gas concentration. However, these relationships were also termite species specific. Using the relationship between mound internal gas concentration and flux from one species to predict mound fluxes from other termite species (as has been done in past) would result in errors of more than 5-fold for CH4 and 3-fold for CO2. 5. This study highlights that CO2 fluxes from termite mounds are generally more than one order of magnitude greater than CH4 fluxes. There are species-specific relationships between CH4 and CO2 fluxes from a~mound, and between the inside mound concentration of a gas and the mound flux emission of the same gas, but these relationships vary greatly among termite species. Consequently, there is no generic relationship that will allow for the prediction of CH4 fluxes from termite mounds of all species.

  15. Correlation between angiogenesis and reduction ratio measured using 201Tl chloride single photon emission computed tomography in patients with oral cavity squamous cell carcinoma

    International Nuclear Information System (INIS)

    Suzuki, Aya; Togawa, Takashi; Omura, Ken

    2004-01-01

    The aim of this study is to examine the correlation between tumor angiogenesis and response to preoperative radiotherapy evaluated using 201 Tl single photon emission computed tomography (Tl SPECT) in oral cavity squamous cell carcinoma (SCC). Tl SPECTs before and after preoperative radiotherapy were obtained from 11 patients diagnosed with SCC in oral cavity. Regions of interest were set around the tumor and scalp respectively, and the ratio of mean counts in the tumor to those in the scalp was calculated (T/N). Immunohistochemical staining for investigating microvessel density of pre-treatment biopsy specimen was performed using CD31 monoclonal antibody. We compared microvessel density with semi-quantitative parameters obtained using Tl SPECT (T/N at pre- an post-treatment, reduction ratio) and prognosis. The subgroup with higher microvessel density showed a significantly higher reduction ratio than the one with lower microvessel density. Regarding prognosis, the subgroup with locoregional recurrent disease exhibited a significantly higher microvessel density than the one without recurrence. In SCC of the oral cavity, there was a significant correlation between microvessel density and response to preoperative radiotherapy. Namely, it was revealed that change of 201 Tl uptake after preoperative radiotherapy correlated with tumor angiogenesis of oral cavity SCC. (author)

  16. Distribution, magnitudes, reactivities, ratios and diurnal patterns of volatile organic compounds in the Valley of Mexico during the MCMA 2002 & 2003 field campaigns

    Directory of Open Access Journals (Sweden)

    E. Velasco

    2007-01-01

    Full Text Available A wide array of volatile organic compound (VOC measurements was conducted in the Valley of Mexico during the MCMA-2002 and 2003 field campaigns. Study sites included locations in the urban core, in a heavily industrial area and at boundary sites in rural landscapes. In addition, a novel mobile-laboratory-based conditional sampling method was used to collect samples dominated by fresh on-road vehicle exhaust to identify those VOCs whose ambient concentrations were primarily due to vehicle emissions. Four distinct analytical techniques were used: whole air canister samples with Gas Chromatography/Flame Ionization Detection (GC-FID, on-line chemical ionization using a Proton Transfer Reaction Mass Spectrometer (PTR-MS, continuous real-time detection of olefins using a Fast Olefin Sensor (FOS, and long path measurements using UV Differential Optical Absorption Spectrometers (DOAS. The simultaneous use of these techniques provided a wide range of individual VOC measurements with different spatial and temporal scales. The VOC data were analyzed to understand concentration and spatial distributions, diurnal patterns, origin and reactivity in the atmosphere of Mexico City. The VOC burden (in ppbC was dominated by alkanes (60%, followed by aromatics (15% and olefins (5%. The remaining 20% was a mix of alkynes, halogenated hydrocarbons, oxygenated species (esters, ethers, etc. and other unidentified VOCs. However, in terms of ozone production, olefins were the most relevant hydrocarbons. Elevated levels of toxic hydrocarbons, such as 1,3-butadiene, benzene, toluene and xylenes, were also observed. Results from these various analytical techniques showed that vehicle exhaust is the main source of VOCs in Mexico City and that diurnal patterns depend on vehicular traffic in addition to meteorological processes. Finally, examination of the VOC data in terms of lumped modeling VOC classes and its comparison to the VOC lumped emissions reported in other

  17. Damage evolution analysis in mortar, during compressive loading using acoustic emission and X-ray tomography: Effects of the sand/cement ratio

    International Nuclear Information System (INIS)

    Elaqra, H.; Godin, N.; Peix, G.; R'Mili, M.; Fantozzi, G.

    2007-01-01

    This paper explores the use of acoustic emission (AE) and X-ray tomography to identify the mechanisms of damage and the fracture process during compressive loading on concrete specimens. Three-dimensional (3D) X-ray tomography image analysis was used to observe defects of virgin mortar specimen under different compressive loads. Cumulative AE events were used to evaluate damage process in real time according to the sand/cement ratio. This work shows that AE and X-ray tomography are complementary nondestructive methods to measure, characterise and locate damage sites in mortar. The effect of the sand proportion on damage and fracture behaviour is studied, in relation with the microstructure of the material

  18. Green leaf volatiles and oxygenated metabolite emission bursts from mesquite branches following light-dark transitions.

    Science.gov (United States)

    Jardine, K; Barron-Gafford, G A; Norman, J P; Abrell, L; Monson, R K; Meyers, K T; Pavao-Zuckerman, M; Dontsova, K; Kleist, E; Werner, C; Huxman, T E

    2012-09-01

    Green leaf volatiles (GLVs) are a diverse group of fatty acid-derived compounds emitted by all plants and are involved in a wide variety of developmental and stress-related biological functions. Recently, GLV emission bursts from leaves were reported following light-dark transitions and hypothesized to be related to the stress response while acetaldehyde bursts were hypothesized to be due to the 'pyruvate overflow' mechanism. In this study, branch emissions of GLVs and a group of oxygenated metabolites (acetaldehyde, ethanol, acetic acid, and acetone) derived from the pyruvate dehydrogenase (PDH) bypass pathway were quantified from mesquite plants following light-dark transitions using a coupled GC-MS, PTR-MS, and photosynthesis system. Within the first minute after darkening following a light period, large emission bursts of both C(5) and C(6) GLVs dominated by (Z)-3-hexen-1-yl acetate together with the PDH bypass metabolites are reported for the first time. We found that branches exposed to CO(2)-free air lacked significant GLV and PDH bypass bursts while O(2)-free atmospheres eliminated the GLV burst but stimulated the PDH bypass burst. A positive relationship was observed between photosynthetic activity prior to darkening and the magnitude of the GLV and PDH bursts. Photosynthesis under (13)CO(2) resulted in bursts with extensive labeling of acetaldehyde, ethanol, and the acetate but not the C(6)-alcohol moiety of (Z)-3-hexen-1-yl acetate. Our observations are consistent with (1) the "pyruvate overflow" mechanism with a fast turnover time (3 h) responsible for the C(6) alcohol moiety of (Z)-3-hexen-1-yl acetate via the 13-lipoxygenase pathway. We conclude that our non-invasive method may provide a new valuable in vivo tool for studies of acetyl-CoA and fatty acid metabolism in plants at a variety of spatial scales.

  19. Coupling field and laboratory measurements to estimate the emission factors of identified and unidentified trace gases for prescribed fires

    Directory of Open Access Journals (Sweden)

    R. J. Yokelson

    2013-01-01

    Full Text Available An extensive program of experiments focused on biomass burning emissions began with a laboratory phase in which vegetative fuels commonly consumed in prescribed fires were collected in the southeastern and southwestern US and burned in a series of 71 fires at the US Forest Service Fire Sciences Laboratory in Missoula, Montana. The particulate matter (PM2.5 emissions were measured by gravimetric filter sampling with subsequent analysis for elemental carbon (EC, organic carbon (OC, and 38 elements. The trace gas emissions were measured by an open-path Fourier transform infrared (OP-FTIR spectrometer, proton-transfer-reaction mass spectrometry (PTR-MS, proton-transfer ion-trap mass spectrometry (PIT-MS, negative-ion proton-transfer chemical-ionization mass spectrometry (NI-PT-CIMS, and gas chromatography with MS detection (GC-MS. 204 trace gas species (mostly non-methane organic compounds (NMOC were identified and quantified with the above instruments. Many of the 182 species quantified by the GC-MS have rarely, if ever, been measured in smoke before. An additional 153 significant peaks in the unit mass resolution mass spectra were quantified, but either could not be identified or most of the signal at that molecular mass was unaccounted for by identifiable species.

    In a second, "field" phase of this program, airborne and ground-based measurements were made of the emissions from prescribed fires that were mostly located in the same land management units where the fuels for the lab fires were collected. A broad variety, but smaller number of species (21 trace gas species and PM2.5 was measured on 14 fires in chaparral and oak savanna in the southwestern US, as well as pine forest understory in the southeastern US and Sierra Nevada mountains of California. The field measurements of emission factors (EF are useful both for modeling and to examine the representativeness of our lab fire EF. The lab EF/field EF ratio for

  20. Use of Statistical Analysis of Acoustic Emission Data on Carbon-Epoxy COPV Materials-of-Construction for Enhanced Felicity Ratio Onset Determination

    Science.gov (United States)

    Abraham, Arick Reed A.; Johnson, Kenneth L.; Nichols, Charles T.; Saulsberry, Regor L.; Waller, Jess M.

    2012-01-01

    Broadband modal acoustic emission (AE) data were acquired during intermittent load hold tensile test profiles on Toray T1000G carbon fiber-reinforced epoxy (C/Ep) single tow specimens. A novel trend seeking statistical method to determine the onset of significant AE was developed, resulting in more linear decreases in the Felicity ratio (FR) with load, potentially leading to more accurate failure prediction. The method developed uses an exponentially weighted moving average (EWMA) control chart. Comparison of the EWMA with previously used FR onset methods, namely the discrete (n), mean (n (raised bar)), normalized (n%) and normalized mean (n(raised bar)%) methods, revealed the EWMA method yields more consistently linear FR versus load relationships between specimens. Other findings include a correlation between AE data richness and FR linearity based on the FR methods discussed in this paper, and evidence of premature failure at lower than expected loads. Application of the EWMA method should be extended to other composite materials and, eventually, composite components such as composite overwrapped pressure vessels. Furthermore, future experiments should attempt to uncover the factors responsible for infant mortality in C/Ep strands.

  1. Coupling field and laboratory measurements to estimate the emission factors of identified and unidentified trace gases for prescribed fires

    Energy Technology Data Exchange (ETDEWEB)

    Yokelson, R. J.; Burling, I. R.; Gilman, J. B.; Warneke, C.; Stockwell, C. E.; de Gouw, J.; Akagi, S. K.; Urbanski, S. P.; Veres, P.; Roberts, J. M.; Kuster, W. C.; Reardon, J.; Griffith, D. W. T.; Johnson, T. J.; Hosseini, S.; Miller, J. W.; Cocker III, D. R.; Jung, H.; Weise, D. R.

    2013-01-01

    Vegetative fuels commonly consumed in prescribed fires were collected from five locations in the southeastern and southwestern U.S. and burned in a series of 77 fires at the U.S. Forest Service Fire Sciences Laboratory in Missoula, Montana. The particulate matter (PM2.5) emissions were measured by gravimetric filter sampling with subsequent analysis for elemental carbon (EC), organic carbon (OC), and 38 elements. The trace gas emissions were measured with a large suite of state-of-the-art instrumentation including an open-path Fourier transform infrared (OP FTIR) spectrometer, proton-transfer-reaction mass spectrometry (PTR-MS), proton-transfer ion-trap mass spectrometry (PIT-MS), negative-ion proton-transfer chemical-ionization mass spectrometry (NI-PT-CIMS), and gas chromatography with MS detection (GC-MS). 204 trace gas species (mostly non-methane organic compounds (NMOC)) were identified and quantified with the above instruments. An additional 152 significant peaks in the unit mass resolution mass spectra were quantified, but either could not be identified or most of the signal at that molecular mass was unaccounted for by identifiable species. As phase II of this study, we conducted airborne and ground-based sampling of the emissions from real prescribed fires mostly in the same land management units where the fuels for the lab fires were collected. A broad variety, but smaller number of species (21 trace gas species and PM2.5) was measured on 14 fires in chaparral and oak savanna in the southwestern US, as well as pine forest understory in the southeastern US and Sierra Nevada mountains of California. These extensive field measurements of emission factors (EF) for temperate biomass burning are useful both for modeling and to examine the representativeness of our lab fire EF. The lab/field EF ratio for the pine understory fuels was not statistically different from one, on average. However, our lab EF for “smoldering compounds” emitted by burning the semi

  2. SU-C-201-07: Towards Clinical Cherenkov Emission Dosimetry: Stopping Power-To-Cherenkov Power Ratios and Beam Quality Specification of Clinical Electron Beams

    International Nuclear Information System (INIS)

    Zlateva, Y; Seuntjens, J; El Naqa, I

    2016-01-01

    Purpose: We propose a Cherenkov emission (CE)-based reference dosimetry method, which in contrast to ionization chamber-based dosimetry, employs spectrum-averaged electron restricted mass collision stopping power-to-Cherenkov power ratios (SCRs), and we examine Monte Carlo-calculated SCRs and beam quality specification of clinical electron beams. Methods: The EGSnrc user code SPRRZnrc was modified to compute SCRs instead of stopping-power ratios (single medium: water; cut-off: CE threshold (observing Spencer-Attix conditions); CE power: Frank-Tamm). SCRs are calculated with BEAMnrc for realistic electron beams with nominal energies of 6–22 MeV from three Varian accelerators (TrueBeam Clinac 21EX, Clinac 2100C/D) and for mono-energetic beams of energies equal to the mean electron energy at the water surface. Sources of deviation between clinical and mono-energetic SCRs are analyzed quantitatively. A universal fit for the beam-quality index R_5_0 in terms of the depth of 50% CE C_5_0 is carried out. Results: SCRs at reference depth are overestimated by mono-energetic values by up to 0.2% for a 6-MeV beam and underestimated by up to 2.3% for a 22-MeV beam. The variation is mainly due to the clinical beam spectrum and photon contamination. Beam angular spread has a small effect across all depths and energies. The influence of the electron spectrum becomes increasingly significant at large depths, while at shallow depths and high beam energies photon contamination is predominant (up to 2.0%). The universal data fit reveals a strong linear correlation between R_5_0 and C_5_0 (ρ > 0.99999). Conclusion: CE is inherent to radiotherapy beams and can be detected outside the beam with available optical technologies, which makes it an ideal candidate for out-of-beam high-resolution 3D dosimetry. Successful clinical implementation of CE dosimetry hinges on the development of robust protocols for converting measured CE to radiation dose. Our findings constitute a key step

  3. The influence of grass silage-to-maize silage ratio and concentrate composition on methane emissions, performance and milk composition of dairy cows.

    Science.gov (United States)

    Hart, K J; Huntington, J A; Wilkinson, R G; Bartram, C G; Sinclair, L A

    2015-06-01

    It is well-established that altering the proportion of starch and fibre in ruminant diets can alter ruminal and post-ruminal digestion, although quantitative evidence that this reduces enteric methane (CH4) production in dairy cattle is lacking. The objective of this study was to examine the effect of varying grass-to-maize silage ratio (70 : 30 and 30 : 70 DM basis), offered ad libitum, with either a concentrate that was high in starch or fibre, on CH4 production, intake, performance and milk composition of dairy cows. A total of 20 cows were allocated to one of the four experimental diets in a two-by-two factorial design run as a Latin square with each period lasting 28 days. Measurements were conducted during the final 7 days of each period. Cows offered the high maize silage ration had a higher dry matter intake (DMI), milk yield, milk energy output and lower CH4 emissions when expressed per kg DMI and per unit of ingested gross energy, but there was no difference in total CH4 production. Several of the milk long-chain fatty acids (FA) were affected by forage treatment with the most notable being an increase in 18:0, 18:1 c9, 18:2 c9 c12 and total mono unsaturated FA, observed in cows offered the higher inclusion of maize silage, and an increase in 18:3 c9 c12 c15 when offered the higher grass silage ration. Varying the composition of the concentrate had no effect on DMI or milk production; however, when the high-starch concentrate was fed, milk protein concentration and milk FAs, 10:0, 14:1, 15:0, 16:1, increased and 18:0 decreased. Interactions were observed for milk fat concentration, being lower in cows offered high-grass silage and high-fibre concentrates compared with the high-starch concentrate, and FA 17:0, which was the highest in milk from cows fed the high-grass silage diet supplemented with the high-starch concentrate. In conclusion, increasing the proportion of maize silage in the diets of dairy cows increased intake and performance, and reduced CH

  4. Field determination of biomass burning emission ratios and factors via open-path FTIR spectroscopy and fire radiative power assessment: headfire, backfire and residual smouldering combustion in African savannahs

    Directory of Open Access Journals (Sweden)

    M. J. Wooster

    2011-11-01

    Full Text Available Biomass burning emissions factors are vital to quantifying trace gas release from vegetation fires. Here we evaluate emissions factors for a series of savannah fires in Kruger National Park (KNP, South Africa using ground-based open path Fourier transform infrared (FTIR spectroscopy and an IR source separated by 150–250 m distance. Molecular abundances along the extended open path are retrieved using a spectral forward model coupled to a non-linear least squares fitting approach. We demonstrate derivation of trace gas column amounts for horizontal paths transecting the width of the advected plume, and find for example that CO mixing ratio changes of ~0.01 μmol mol−1 [10 ppbv] can be detected across the relatively long optical paths used here. Though FTIR spectroscopy can detect dozens of different chemical species present in vegetation fire smoke, we focus our analysis on five key combustion products released preferentially during the pyrolysis (CH2O, flaming (CO2 and smoldering (CO, CH4, NH3 processes. We demonstrate that well constrained emissions ratios for these gases to both CO2 and CO can be derived for the backfire, headfire and residual smouldering combustion (RSC stages of these savannah fires, from which stage-specific emission factors can then be calculated. Headfires and backfires often show similar emission ratios and emission factors, but those of the RSC stage can differ substantially. The timing of each fire stage was identified via airborne optical and thermal IR imagery and ground-observer reports, with the airborne IR imagery also used to derive estimates of fire radiative energy (FRE, allowing the relative amount of fuel burned in each stage to be calculated and "fire averaged" emission ratios and emission factors to be determined. These "fire averaged" metrics are dominated by the headfire contribution, since the FRE data indicate that the vast majority

  5. Atmospheric CH4 and CO2 enhancements and biomass burning emission ratios derived from satellite observations of the 2015 Indonesian fire plumes

    Directory of Open Access Journals (Sweden)

    R. J. Parker

    2016-08-01

    subsequent large increases in regional greenhouse gas concentrations. CH4 is particularly enhanced, due to the dominance of smouldering combustion in peatland fires, with CH4 total column values typically exceeding 35 ppb above those of background “clean air” soundings. By examining the CH4 and CO2 excess concentrations in the fire-affected GOSAT observations, we determine the CH4 to CO2 (CH4 ∕ CO2 fire emission ratio for the entire 2-month period of the most extreme burning (September–October 2015, and also for individual shorter periods where the fire activity temporarily peaks. We demonstrate that the overall CH4 to CO2 emission ratio (ER for fires occurring in Indonesia over this time is 6.2 ppb ppm−1. This is higher than that found over both the Amazon (5.1 ppb ppm−1 and southern Africa (4.4 ppb ppm−1, consistent with the Indonesian fires being characterised by an increased amount of smouldering combustion due to the large amount of organic soil (peat burning involved. We find the range of our satellite-derived Indonesian ERs (6.18–13.6 ppb ppm−1 to be relatively closely matched to that of a series of close-to-source, ground-based sampling measurements made on Kalimantan at the height of the fire event (7.53–19.67 ppb ppm−1, although typically the satellite-derived quantities are slightly lower on average. This seems likely because our field sampling mostly intersected smaller-scale peat-burning plumes, whereas the large-scale plumes intersected by the GOSAT Thermal And Near infrared Sensor for carbon Observation – Fourier Transform Spectrometer (TANSO-FTS footprints would very likely come from burning that was occurring in a mixture of fuels that included peat, tropical forest and already-cleared areas of forest characterised by more fire-prone vegetation types than the natural rainforest biome (e.g. post-fire areas of ferns and scrubland, along with agricultural vegetation.The ability to determine large-scale ERs from

  6. Biogenic volatile organic compound emissions from senescent maize leaves and a comparison with other leaf developmental stages

    Science.gov (United States)

    Mozaffar, A.; Schoon, N.; Bachy, A.; Digrado, A.; Heinesch, B.; Aubinet, M.; Fauconnier, M.-L.; Delaplace, P.; du Jardin, P.; Amelynck, C.

    2018-03-01

    Plants are the major source of Biogenic Volatile Organic Compounds (BVOCs) which have a large influence on atmospheric chemistry and the climate system. Therefore, understanding of BVOC emissions from all abundant plant species at all developmental stages is very important. Nevertheless, investigations on BVOC emissions from even the most widespread agricultural crop species are rare and mainly confined to the healthy green leaves. Senescent leaves of grain crop species could be an important source of BVOCs as almost all the leaves senesce on the field before being harvested. For these reasons, BVOC emission measurements have been performed on maize (Zea mays L.), one of the most cultivated crop species in the world, at all the leaf developmental stages. The measurements were performed in controlled environmental conditions using dynamic enclosures and proton transfer reaction mass spectrometry (PTR-MS). The main compounds emitted by senescent maize leaves were methanol (31% of the total cumulative BVOC emission on a mass of compound basis) and acetic acid (30%), followed by acetaldehyde (11%), hexenals (9%) and m/z 59 compounds (acetone/propanal) (7%). Important differences were observed in the temporal emission profiles of the compounds, and both yellow leaves during chlorosis and dry brown leaves after chlorosis were identified as important senescence-related BVOC sources. Total cumulative BVOC emissions from senescent maize leaves were found to be among the highest for senescent Poaceae plant species. BVOC emission rates varied strongly among the different leaf developmental stages, and senescent leaves showed a larger diversity of emitted compounds than leaves at earlier stages. Methanol was the compound with the highest emissions for all the leaf developmental stages and the contribution from the young-growing, mature, and senescent stages to the total methanol emission by a typical maize leaf was 61, 13, and 26%, respectively. This study shows that BVOC

  7. Temporal variability and sources of VOCs in urban areas of the eastern Mediterranean

    Directory of Open Access Journals (Sweden)

    C. Kaltsonoudis

    2016-11-01

    Full Text Available During the summer of 2012 volatile organic compounds (VOCs were monitored by proton transfer reaction mass spectrometry (PTR-MS in urban sites, in Athens and Patras, two of the largest cities in Greece. Also, during the winter of 2013, PTR-MS measurements were conducted in the center of the city of Athens. Positive matrix factorization (PMF was applied to the VOC measurements to gain insights about their sources. In summer most of the measured VOCs were due to biogenic and traffic emissions. Isoprene, monoterpenes, and several oxygenated VOCs (oVOCs originated mainly from vegetation either directly or as oxidation products. Isoprene average concentrations in Patras and Athens were 1 and 0.7 ppb respectively, while the monoterpene concentrations were 0.3 and 0.9 ppb respectively. Traffic was the main source of aromatic compounds during summer. For Patras and Athens the average concentrations of benzene were 0.1 and 0.2 ppb, of toluene 0.3 and 0.8 ppb, and of the xylenes 0.3 and 0.7 ppb respectively. Winter measurements in Athens revealed that biomass burning used for residential heating was a major VOC source contributing both aromatic VOCs and biogenic compounds such as monoterpenes. Several episodes related to biomass burning were identified and emission ratios (ERs and emission factors (EFs were estimated.

  8. Quantifying impacts on air quality of vehicular emissions in Sao Paulo and Rio de Janeiro

    Science.gov (United States)

    Artaxo, Paulo; Ferreira de Brito, Joel; Godoy, José Marcus; Luiza Godoy, Maria; Junior, Djacinto

    2016-04-01

    Vehicular emissions in megacities such as Sao Paulo and Rio de Janeiro are increasingly becoming a global issue. The São Paulo Metropolitan Area (SPMA), located in Southeast of Brazil, is a megacity with a population of 18 million people, with 7 million cars and large-scale industrial emissions. Rio de Janeiro is also a large city with different meteorology than São Paulo. All cars in Brazil runs gasohol, with 23% ethanol in gasoline, and for the last 10 years, flex cars that can run on gasohol, ethanol or any mixture dominate the market. Overall ethanol accounts for about 30-40% of fuel burned in both cities. To improve the understanding of vehicular emission impacts on aerosol composition and life cycle in these two large megacities a source apportionment study, combining online and offline measurements, was performed. Aerosols were collected for one year to capture seasonal variability at 4 sites in each city, with inorganic and organic aerosol component being sampled. Organic and elemental carbon were measured using a Sunset Laboratory Dual Optics (transmission and reflectance) Carbon Analyzer and about 22 trace elements has been measured using polarized X-Ray Fluorescence (XRF). Aerosol mass and black carbon were also measured, as well as trace gases to help in aerosol source apportionment. In Sao Paulo, the average PM2.5 mass concentration obtained varied from 9.6 to 12.2 μg m-3 for the several sites, and similar concentrations were measured in Rio de Janeiro. At all sites, organic matter (OM) has dominated fine mode aerosol concentration with 42 to 60% of the aerosol mass. EC accounted for 21 to 31% of fine mode aerosol mass concentration. Sulfate accounted for 21 to 26% of PM2.5 for the sites. Aerosol source apportionment was done with receptor analysis and integration with online data such as PTR-MS, Aethalometers, Nephelometers and ACSM helped to apportion vehicular emissions. For the 8 sites operated in Sao Paulo and Rio de Janeiro, vehicular

  9. Experimental investigation on the availability, performance, combustion and emission distinctiveness of bael oil/ diesel/ diethyl ether blends powered in a variable compression ratio diesel engine

    Science.gov (United States)

    Krishnamoorthi, M.; Malayalamurthi, R.

    2018-02-01

    The present work aims at experimental investigation on the combined effect of injection timing (IT) and injection pressure (IP) on the performance and emissions characteristics, and exergy analysis of a compression-ignition (CI) engine powered with bael oil blends. The tests were conducted using ternary blends of bael oil, diethyl ether (DEE) and neat diesel (D) at various engine loads at a constant engine speed (1500 rpm). With B2 (60%D + 30%bael oil+10%DEE) fuel, the brake thermal efficiency (BTE) of the engine is augmented by 3.5%, reduction of 4.7% of oxides of nitrogen (NOx) emission has been observed at 100% engine load with 250 bar IP. B2 fuel exhibits 7% lower scale of HC emissions compared to that of diesel fuel at 100% engine load in 23 °bTDC IT. The increment in both cooling water and exhaust gas availabilities lead to increasing exergy efficiency with increasing load. The exergy efficiency of about 62.17% has been recorded by B2 fuel at an injection pressure of 230 IP bar with 100% load. On the whole, B2 fuel displays the best performance and combustion characteristics. It also exhibits better characteristics of emissions level in terms of lower HC, smoke opacity and NOx.

  10. Combination of the ionic-to-atomic line intensity ratios from two test elements for the diagnostic of plasma temperature and electron number density in Inductively Coupled Plasma Atomic Emission Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Tognoni, E. [Istituto per i Processi Chimico-Fisici, Area della Ricerca del Consiglio Nazionale delle Ricerche Via Moruzzi 1, 56124 Pisa (Italy)], E-mail: tognoni@ipcf.cnr.it; Hidalgo, M.; Canals, A. [Departamento de Quimica Analitica, Nutricion y Bromatologia. Universidad de Alicante. Apdo. 99, 03080, Alicante (Spain); Cristoforetti, G.; Legnaioli, S.; Salvetti, A.; Palleschi, V. [Istituto per i Processi Chimico-Fisici, Area della Ricerca del Consiglio Nazionale delle Ricerche Via Moruzzi 1, 56124 Pisa (Italy)

    2007-05-15

    In Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES) spectrochemical analysis, the MgII(280.270 nm)/MgI(285.213 nm) ionic to atomic line intensity ratio is commonly used as a monitor of the robustness of operating conditions. This approach is based on the univocal relationship existing between intensity ratio and plasma temperature, for a pure argon atmospheric ICP in thermodynamic equilibrium. In a multi-elemental plasma in the lower temperature range, the measurement of the intensity ratio may not be sufficient to characterize temperature and electron density. In such a range, the correct relationship between intensity ratio and plasma temperature can be calculated only when the complete plasma composition is known. We propose the combination of the line intensity ratios of two test elements (double ratio) as an effective diagnostic tool for a multi-elemental low temperature LTE plasma of unknown composition. In particular, the variation of the double ratio allows us discriminating changes in the plasma temperature from changes in the electron density. Thus, the effects on plasma excitation and ionization possibly caused by introduction of different samples and matrices in non-robust conditions can be more accurately interpreted. The method is illustrated by the measurement of plasma temperature and electron density in a specific analytic case.

  11. Golden Ratio

    Indian Academy of Sciences (India)

    Our attraction to another body increases if the body is symmetricaland in proportion. If a face or a structure is in proportion,we are more likely to notice it and find it beautiful.The universal ratio of beauty is the 'Golden Ratio', found inmany structures. This ratio comes from Fibonacci numbers.In this article, we explore this ...

  12. Golden Ratio

    Indian Academy of Sciences (India)

    Keywords. Fibonacci numbers, golden ratio, Sanskrit prosody, solar panel. Abstract. Our attraction to another body increases if the body is symmetricaland in proportion. If a face or a structure is in proportion,we are more likely to notice it and find it beautiful.The universal ratio of beauty is the 'Golden Ratio', found inmany ...

  13. Golden Ratio

    Indian Academy of Sciences (India)

    Our attraction to another body increases if the body is sym- metrical and in proportion. If a face or a structure is in pro- portion, we are more likely to notice it and find it beautiful. The universal ratio of beauty is the 'Golden Ratio', found in many structures. This ratio comes from Fibonacci numbers. In this article, we explore this ...

  14. Influence of vehicular emissions on atmospheric CH4 and NMHC mixing ratios and its correlation with CO and other VOCs tracers in Mexico City

    Science.gov (United States)

    Solano-Murillo, M.; Torres-Jardón, R.; Ruiz-Suárez, L. G.; Barrera-Huertas, H.; Hernandez-Solis, J. M.

    2016-12-01

    The Mexico City Metropolitan Area (MCMA) is one of the world's largest and most polluted urban areas. A recent GHC emission inventory for MCMA suggests that vehicular emissions contribute with around 37% of CH4, followed by landfills and dump garbage areas (30%) and construction and manufacturing (27%). Contrary to other urban areas, natural gas is not the main fuel used in MCMA, neither for domestic and industrial heating, nor for transportation. Therefore, there is a great uncertainty about who is the main contributor of CH4 emissions. An intensive monitoring campaign of methane (CH4), Non-methane hydrocarbons (NMHC) and carbon monoxide (CO) was performed between February and March 2015 in southwest MCMA. Methane concentrations showed sometimes a diurnal pattern similar to those of CO and to NMHC but most of the time this similarity was lost (CH4 vs CO, R2 = 0.27; CH4 vs NMHC, R2 = 0.28). However, NMHC correlated well with CO (R2 = 0.75). The intercepts of the CH4-CO correlation resulted in [CH4] 1.8 ppm and that of the CO-NMHC correlation in [CO] 0.080 ppb. The lack of agreement between CH4 and CO indicates these species do not come from the same sources. The results suggest that vehicular emissions are not significant contributors to atmospheric CH4 and that the background methane concentration has not change significantly in 25 years. An attempt to correlate some tracers COVs tracers of vehicular and biomass burning with CH4, NMHC and CH4 is done.

  15. Effective tuning of the ratio of red to green emission of Ho{sup 3+} ions in single LiLuF{sub 4} microparticle via codoping Ce{sup 3+} ions

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Wei, E-mail: gaowei@xupt.edu.cn; Dong, Jun; Liu, Jihong; Yan, Xuewen

    2016-09-15

    Yb{sup 3+}/Ho{sup 3+} codoped LiLuF{sub 4} microparticles have been successfully prepared via a facile hydrothermal method. The crystal phase and morphology of LiLuF{sub 4} microparticles were inspected by x-ray diffraction and scanning electron microscope, respectively. The upconversion emission of single LiLuF{sub 4}: Yb{sup 3+}/Ho{sup 3+} microparticle was carefully studied by a confocal microscopy setup under NIR 980 nm excitation. With the increase of Ce{sup 3+} ion concentrations of 12%, the ratio of red to green emission of the Ho{sup 3+} ions of single LiLuF{sub 4} microparticle was boosted about 17-fold, and the output colors were tuned from green to red, which is due to the two efficient cross-relaxation between Ho{sup 3+} and Ce{sup 3+} ions enhances the red and suppresses the green in the emission processes. To investigate the optical properties of the single microparticle or nanoparticle through the confocal microscopy setup can effectively avoid the influence of surrounding particle or environment, and could provide more precise information for better exploring the emission mechanisms of rare earth ions. The tunable upconversion emission of Ho{sup 3+} in single LiLuF{sub 4} microparticle in this work will have great potential applications in the micro optoelectronic devices and color display applications. - Highlights: • The optical properties of the single LiLuF4: Yb3+/Ho3+/Ce3+ microparticle were studied. • The output colors of single LiLuF4 microparticle were tuned from green to red. • The upconversion mechanisms between Ho3+ and Ce3+ ions were discussed based on emission spectrum.

  16. Sex ratios

    OpenAIRE

    West, Stuart A; Reece, S E; Sheldon, Ben C

    2002-01-01

    Sex ratio theory attempts to explain variation at all levels (species, population, individual, brood) in the proportion of offspring that are male (the sex ratio). In many cases this work has been extremely successful, providing qualitative and even quantitative explanations of sex ratio variation. However, this is not always the situation, and one of the greatest remaining problems is explaining broad taxonomic patterns. Specifically, why do different organisms show so ...

  17. Assessment of n-pentanol/Calophyllum inophyllum/diesel blends on the performance, emission, and combustion characteristics of a constant-speed variable compression ratio direct injection diesel engine.

    Science.gov (United States)

    Ramakrishnan, Purnachandran; Kasimani, Ramesh; Peer, Mohamed Shameer; Rajamohan, Sakthivel

    2018-05-01

    Alcohol is used as an additive for a long time with the petroleum-based fuels. In this study, the higher alcohol, n-pentanol, was used as an additive to Calophyllum inophyllum (CI) biodiesel/diesel blends at 10, 15, and 20% by volume. In all blends, the ratio of CI was maintained at 20% by volume. The engine characteristics of the pentanol fuel blends were compared with the diesel and CI20 (Calophyllum inophyllum 20% and diesel 80%) biodiesel blend. The nitrogen oxide (NO) emission of the pentanol fuel blends showed an increased value than CI20 and neat diesel fuel. The carbon dioxide (CO 2 ) also increased with increase in pentanol addition with the fuel blends than CI20 fuel blend and diesel. The carbon monoxide (CO) and hydrocarbon (HC) emissions were decreased with increase in pentanol proportion in the blend than the CI20 fuel and diesel. The smoke emission was reduced and the combustion characteristics of the engine were also improved by using pentanol blended fuels. From this investigation, it is suggested that 20% pentanol addition with the biodiesel/diesel fuel is suitable for improved performance and combustion characteristics of a diesel engine without any engine modifications, whereas CO 2 and NO emissions increased with addition of pentanol due to effective combustion.

  18. Linking annual N2O emission in organic soils to mineral nitrogen input as estimated by heterotrophic respiration and soil C/N ratio.

    Science.gov (United States)

    Mu, Zhijian; Huang, Aiying; Ni, Jiupai; Xie, Deti

    2014-01-01

    Organic soils are an important source of N2O, but global estimates of these fluxes remain uncertain because measurements are sparse. We tested the hypothesis that N2O fluxes can be predicted from estimates of mineral nitrogen input, calculated from readily-available measurements of CO2 flux and soil C/N ratio. From studies of organic soils throughout the world, we compiled a data set of annual CO2 and N2O fluxes which were measured concurrently. The input of soil mineral nitrogen in these studies was estimated from applied fertilizer nitrogen and organic nitrogen mineralization. The latter was calculated by dividing the rate of soil heterotrophic respiration by soil C/N ratio. This index of mineral nitrogen input explained up to 69% of the overall variability of N2O fluxes, whereas CO2 flux or soil C/N ratio alone explained only 49% and 36% of the variability, respectively. Including water table level in the model, along with mineral nitrogen input, further improved the model with the explanatory proportion of variability in N2O flux increasing to 75%. Unlike grassland or cropland soils, forest soils were evidently nitrogen-limited, so water table level had no significant effect on N2O flux. Our proposed approach, which uses the product of soil-derived CO2 flux and the inverse of soil C/N ratio as a proxy for nitrogen mineralization, shows promise for estimating regional or global N2O fluxes from organic soils, although some further enhancements may be warranted.

  19. PTR-MS Assessment of Photocatalytic and Sorption-Based Purification of Recirculated Cabin Air during Simulated 7-h Flights with High Passenger Density

    DEFF Research Database (Denmark)

    Wisthaler, Armin; Strøm-Tejsen, Peter; Fang, Lei

    2007-01-01

    Four different air purification conditions were established in a simulated 3-row 21-seat section of an aircraft cabin: no air purifier; a photocatalytic oxidation unit with an adsorptive prefilter; a second photocatalytic unit with an adsorptive prefil-ter; and a two-stage sorptionbased air filter...... (gas-phase absorption and adsorption). The air purifiers placed in the cabin air recirculation system were commercial prototypes developed for use in aircraft cabin systems. The four conditions were established in balanced order on 4 successive days of each of 4 successive weeks during simulated 7-h...... flights with 17 occupants. Protontransfer reaction mass spectrometry was used to assess organic gas-phase pollutants and the performance of each air purifier. The concentration of most organic pollutants present in aircraft cabin air was effi-ciently reduced by all three units. The photocatalytic units...

  20. Investigation of the aroma of commercial peach (Prunus persica L. Batsch) types by Proton Transfer Reaction-Mass Spectrometry (PTR-MS) and sensory analysis

    NARCIS (Netherlands)

    Cardoso Ferreira Pinhancos de Bianchi, Tiago; Weesepoel, Yannick; Koot, Alex; Iglesias, Ignasi; Eduardo, Iban; Gratacós-Cubarsí, Marta; Guerrero, Luis; Hortós, Maria; Ruth, van Saskia

    2017-01-01

    The aim of this study was to investigate the aroma and sensory profiles of various types of peaches (Prunus persica L. Batsch.). Forty-three commercial cultivars comprising peaches, flat peaches, nectarines, and canning peaches (pavías) were grown over two consecutive harvest years. Fruits were

  1. Effects of Euglena (Euglena gracilis) supplemented to diet (forage: concentrate ratios of 60:40) on the basic ruminal fermentation and methane emissions in in vitro condition

    OpenAIRE

    Aemiro, Ashagrie; Watanabe, Shota; Suzuki, Kengo; Hanada, Masaaki; Umetsu, Kazutaka

    2016-01-01

    An in vitro study was conducted to investigate the effect of different concentrations of Euglena (Euglena gracilis) on CH4 production, dry matter (DM) digestibility, volatile fatty acid (VFA) and ammonia N(NH3-N) concentration as well as on the protozoa population. The treatments considered were Euglena at concentrations of 0.0, 50, 100, 200, 400 and 1000 g/kg dry matter (DM) of the substrate (60:40 forage: concentrate ratio) incubated for 24 and 96 h using an in vitro continuous gas producti...

  2. Relationship between lung-to-heart uptake ratio of technetium-99m-tetrofosmin during exercise myocardial single photon emission computed tomographic imaging and the number of diseased coronary arteries in patients with effort angina pectoris without myocardial infarction

    International Nuclear Information System (INIS)

    Okajima, Toshiya; Ueshima, Kenji; Nishiyama, Osamu; Ogawa, Muneyoshi; Ohuchi, Mami; Saitoh, Masahiko; Hiramori, Katsuhiko

    2004-01-01

    Increased lung uptake of thallium-201 in exercise myocardial perfusion imaging is a reliable marker of multivessel disease in patients with ischemic heart disease. This study investigated whether the lung-to-heart uptake ratio with technetium-99m ( 99m Tc)-tetrofosmin also provides valuable information to detect patients with multivessel disease. Fifty-three consecutive patients (35 men, 18 women, mean age 66±11 years; single-vessel disease: 29, double-vessel disease: 16, triple-vessel disease: 8) with stable effort angina pectoris without prior myocardial infarction and 17 control subjects (12 men, 5 women, mean age 62±9 years) underwent exercise myocardial perfusion imaging with 99m Tc-tetrofosmin and coronary angiography in January 2000 to December 2002. The lung-to-heart uptake ratio was calculated on an anterior projection before reconstruction of the exercise single photon emission computed tomographic images. The mean lung-to-heart uptake ratio was 0.34±0.04, 0.38±0.07, 0.41±0.05, and 0.46±0.09, in patients with normal coronary, single-vessel disease, double-vessel disease, and triple-vessel disease, respectively. Significantly higher lung-to-heart uptake ratio was associated with more diseased vessels (p 99m Tc-tetrofosmin can provide clinically useful information to detect multivessel disease in patients with ischemic heart disease. (author)

  3. Evidence of feasible hardness test on Mars using ratio of ionic/neutral emission intensities measured with laser-induced breakdown spectroscopy in low pressure CO_2 ambient gas

    International Nuclear Information System (INIS)

    Abdulmadjid, Syahrun Nur; Lahna, Kurnia; Idris, Nasrullah; Pardede, Marincan; Suyanto, Hery; Ramli, Muliadi; Marpaung, Alion Mangasi; Hedwig, Rinda; Lie, Zener Sukra; Kurniawan, Davy Putra; Kurniawan, Koo Hendrik; Lie, Tjung Jie; Tjia, May On; Kagawa, Kiichiro

    2016-01-01

    An experimental study is conducted on the possibility and viability of performing hardness measurement of the various stone and chert samples in low pressure (600 Pa) CO_2 ambient gas, a condition that is encountered in the Mars atmosphere. For this study, a nanosecond Nd-YAG laser is employed to generate plasma emission from the samples with different degrees of hardness. This technique is developed in light of the role of the shock wave in the generation of a laser-induced plasma. It was previously shown that the speed of the shock front depends on the hardness of the sample, and a positive relationship was found between the speed of the shock front and the ionization rate of the ablated atoms. Hence, the ratio of the intensity between the Mg II 279.5 nm and Mg I 285.2 nm emission lines detected from the laser-induced plasma can be used to estimate the hardness of a material. In fact, it is shown that the ratio changes linearly with respect to changes of sample hardness. The result has thus demonstrated the feasibility and viability of using LIBS for non contact hardness measurement on Mars.

  4. Evidence of feasible hardness test on Mars using ratio of ionic/neutral emission intensities measured with laser-induced breakdown spectroscopy in low pressure CO{sub 2} ambient gas

    Energy Technology Data Exchange (ETDEWEB)

    Abdulmadjid, Syahrun Nur; Lahna, Kurnia; Idris, Nasrullah [Department of Physics, Faculty of Mathematics and Natural Sciences, Syiah Kuala University, Darussalam, Banda Aceh 23111, NAD (Indonesia); Pardede, Marincan [Department of Electrical Engineering, University of Pelita Harapan, 1100 M.H. Thamrin Boulevard, Lippo Village, Tangerang 15811 (Indonesia); Suyanto, Hery [Department of Physics, Faculty of Mathematics and Natural Sciences, Udayana University, Kampus Bukit Jimbaran, Denpasar 80361, Bali (Indonesia); Ramli, Muliadi [Department of Chemistry, Faculty of Mathematics and Natural Sciences, Syiah Kuala University, Darussalam, Banda Aceh 23111, NAD (Indonesia); Marpaung, Alion Mangasi [Department of Physics, Faculty of Mathematics and Natural Sciences, Jakarta State University, 10 Rawamangun, Jakarta 13220 (Indonesia); Hedwig, Rinda [Department of Computer Engineering, Bina Nusantara University, 9 K.H. Syahdan, Jakarta 14810 (Indonesia); Lie, Zener Sukra [Department of Computer Engineering, Bina Nusantara University, 9 K.H. Syahdan, Jakarta 14810 (Indonesia); Research Center of Maju Makmur Mandiri Foundation, 40/80 Srengseng Raya, Jakarta 11630 (Indonesia); Kurniawan, Davy Putra; Kurniawan, Koo Hendrik, E-mail: kurnia18@cbn.net.id; Lie, Tjung Jie [Research Center of Maju Makmur Mandiri Foundation, 40/80 Srengseng Raya, Jakarta 11630 (Indonesia); Tjia, May On [Research Center of Maju Makmur Mandiri Foundation, 40/80 Srengseng Raya, Jakarta 11630 (Indonesia); Physics of Magnetism and Photonics Group, Faculty of Mathematics and Natural Sciences, Bandung Institute of Technology, 10 Ganesha, Bandung 40132 (Indonesia); Kagawa, Kiichiro [Research Center of Maju Makmur Mandiri Foundation, 40/80 Srengseng Raya, Jakarta 11630 (Indonesia); Fukui Science Education Academy, Takagi Chuo 2 chome, Fukui 910-0804 (Japan)

    2016-04-28

    An experimental study is conducted on the possibility and viability of performing hardness measurement of the various stone and chert samples in low pressure (600 Pa) CO{sub 2} ambient gas, a condition that is encountered in the Mars atmosphere. For this study, a nanosecond Nd-YAG laser is employed to generate plasma emission from the samples with different degrees of hardness. This technique is developed in light of the role of the shock wave in the generation of a laser-induced plasma. It was previously shown that the speed of the shock front depends on the hardness of the sample, and a positive relationship was found between the speed of the shock front and the ionization rate of the ablated atoms. Hence, the ratio of the intensity between the Mg II 279.5 nm and Mg I 285.2 nm emission lines detected from the laser-induced plasma can be used to estimate the hardness of a material. In fact, it is shown that the ratio changes linearly with respect to changes of sample hardness. The result has thus demonstrated the feasibility and viability of using LIBS for non contact hardness measurement on Mars.

  5. Thallium-201 right lung/heart ratio during exercise in patients with coronary artery disease: relation to thallium-201 myocardial single-photon emission tomography, rest and exercise left ventricular function and coronary angiography

    International Nuclear Information System (INIS)

    Morel, O.; Pezard, P.; Le Jeune, J.J.; Denizot, B.; Jallet, P.; Furber, A.; Vielle, B.

    1999-01-01

    The aim of this study was to correlate lung thallium-201 uptake on exercise with 201 Tl single-photon emission tomography (SPET) myocardial perfusion imaging, rest and exercise equilibrium radionuclide angiographic and coronary angiographic findings in patients with coronary artery disease (CAD) using a simple, reproducible lung/heart (L/H) ratio that would be easy to use in clinical practice. L/H ratio was defined on the anterior planar image obtained during exercise 201 Tl SPET acquisition as the mean counts per pixel in an entire right lung field region of interest divided by the mean counts per pixel in the hottest myocardial wall region of interest. We studied 103 patients. Fifty-nine patients (group I) with 201 Tl SPET, radionuclide angiographic and coronary angiographic variables. The group I L/H ratio of 0.35±0.05 (mean ±1 SD) was significantly lower (P 0.45 (mean+2 SD in group I) was considered abnormal. In group II, L/H ratio showed a significant correlation with stress and rest 201 Tl perfusion defect size (r=0.39 and r=0.42, P<0.01, respectively), but not with extent of ischaemic myocardium. The mean L/H ratio was 0.41±0.10 in patients with one-vessel disease (n=15), 0.46±0.08 in those with two-vessel disease (n=17) and 0.47±0.12 in those with three-vessel disease (n=12), but no significant difference was found between the three subgroups. L/H ratio showed a significant inverse relation with rest and exercise left ventricular ejection fraction (r=-0.37 and r=-0.50, P<0.05 and P<0.001, respectively). Using stepwise multiple regression analysis, exercise left ventricular ejection fraction and previous history of hypertension were the sole two variables independently predictive of the L/H ratio. In conclusion, although lung thallium uptake is usually found to correlate with extent and severity of CAD, increased L/H ratio should primarily be considered as a marker of exercise-induced left ventricular systolic and perhaps diastolic dysfunction, probably

  6. Correlation between nitrous oxide (N2O) emission and carbon to nitrogen (COD/N) ratio in denitrification process: a mitigation strategy to decrease greenhouse gas emission and cost of operation.

    Science.gov (United States)

    Andalib, Mehran; Taher, Edris; Donohue, Joseph; Ledwell, Sam; Andersen, Mikkel H; Sangrey, Karla

    2018-01-01

    The reliability and accuracy of in-situ ion selective electrode and ultraviolet (NO x ) probes have been investigated at four different treatment plants with different operational conditions. This study shows that the mentioned probes tend to compromise their accuracy and trending stability at lower NO x of production at non-detect dissolved oxygen concentrations and pH of 7-7.2 were found to be a function of influent nitrogen load or the ratio of COD/N INFLUENT . Finally, using an N 2 O probe as a proxy sensor for nitrates is proposed as a measured variable in the PI feedback in the automation of the denitrification process with a NO x set point of <1.2 mg N/L).

  7. Sci-Thur AM: YIS – 04: Stopping power-to-Cherenkov power ratios and beam quality specification for clinical Cherenkov emission dosimetry of electrons: beam-specific effects and experimental validation

    International Nuclear Information System (INIS)

    Zlateva, Yana; Seuntjens, Jan; El Naqa, Issam

    2016-01-01

    Purpose: To advance towards clinical Cherenkov emission (CE)-based dosimetry by investigating beam-specific effects on Monte Carlo-calculated electron-beam stopping power-to-CE power ratios (SCRs), addressing electron beam quality specification in terms of CE, and validating simulations with measurements. Methods: The EGSnrc user code SPRRZnrc, used to calculate Spencer-Attix stopping-power ratios, was modified to instead calculate SCRs. SCRs were calculated for 6- to 22-MeV clinical electron beams from Varian TrueBeam, Clinac 21EX, and Clinac 2100C/D accelerators. Experiments were performed with a 20-MeV electron beam from a Varian TrueBeam accelerator, using a diffraction grating spectrometer with optical fiber input and a cooled back-illuminated CCD. A fluorophore was dissolved in the water to remove CE signal anisotropy. Results: It was found that angular spread of the incident beam has little effect on the SCR (≤ 0.3% at d max ), while both the electron spectrum and photon contamination increase the SCR at shallow depths and decrease it at large depths. A universal data fit of R 50 in terms of C 50 (50% CE depth) revealed a strong linear dependence (R 2 > 0.9999). The SCR was fit with a Burns-type equation (R 2 = 0.9974, NRMSD = 0.5%). Below-threshold incident radiation was found to have minimal effect on beam quality specification (< 0.1%). Experiments and simulations were in good agreement. Conclusions: Our findings confirm the feasibility of the proposed CE dosimetry method, contingent on computation of SCRs from additional accelerators and on further experimental validation. This work constitutes an important step towards clinical high-resolution out-of-beam CE dosimetry.

  8. Sci-Thur AM: YIS – 04: Stopping power-to-Cherenkov power ratios and beam quality specification for clinical Cherenkov emission dosimetry of electrons: beam-specific effects and experimental validation

    Energy Technology Data Exchange (ETDEWEB)

    Zlateva, Yana; Seuntjens, Jan; El Naqa, Issam [McGill University, Cedars Cancer Centre, University of Michigan (United States)

    2016-08-15

    Purpose: To advance towards clinical Cherenkov emission (CE)-based dosimetry by investigating beam-specific effects on Monte Carlo-calculated electron-beam stopping power-to-CE power ratios (SCRs), addressing electron beam quality specification in terms of CE, and validating simulations with measurements. Methods: The EGSnrc user code SPRRZnrc, used to calculate Spencer-Attix stopping-power ratios, was modified to instead calculate SCRs. SCRs were calculated for 6- to 22-MeV clinical electron beams from Varian TrueBeam, Clinac 21EX, and Clinac 2100C/D accelerators. Experiments were performed with a 20-MeV electron beam from a Varian TrueBeam accelerator, using a diffraction grating spectrometer with optical fiber input and a cooled back-illuminated CCD. A fluorophore was dissolved in the water to remove CE signal anisotropy. Results: It was found that angular spread of the incident beam has little effect on the SCR (≤ 0.3% at d{sub max}), while both the electron spectrum and photon contamination increase the SCR at shallow depths and decrease it at large depths. A universal data fit of R{sub 50} in terms of C{sub 50} (50% CE depth) revealed a strong linear dependence (R{sup 2} > 0.9999). The SCR was fit with a Burns-type equation (R{sup 2} = 0.9974, NRMSD = 0.5%). Below-threshold incident radiation was found to have minimal effect on beam quality specification (< 0.1%). Experiments and simulations were in good agreement. Conclusions: Our findings confirm the feasibility of the proposed CE dosimetry method, contingent on computation of SCRs from additional accelerators and on further experimental validation. This work constitutes an important step towards clinical high-resolution out-of-beam CE dosimetry.

  9. Tracing the link between plant volatile organic compound emissions and CO2 fluxes and by stable isotopes

    Science.gov (United States)

    Werner, Christiane; Wegener, Frederik; Jardine, Kolby

    2015-04-01

    The vegetation exerts a large influence on the atmosphere through the emission of volatile organic compounds (VOCs) and the emission and uptake of the greenhouse gas CO2. Despite the enormous importance, processes controlling plant carbon allocation into primary and secondary metabolism, such as photosynthetic carbon uptake, respiratory CO2 emission and VOC synthesis, remains unclear. Moreover, vegetation-atmosphere CO2 exchange is associated with a large isotopic imprint due to photosynthetic carbon isotope discrimination and 13C-fractionation during respiratory CO2 release1. The latter has been proposed to be related to carbon partitioning in the metabolic branching points of the respiratory pathways and secondary metabolism, which are linked via a number of interfaces including the central metabolite pyruvate. Notably, it is a known substrate in a large array of secondary pathways leading to the biosynthesis of many volatile organic compounds (VOCs), such as volatile isoprenoids, oxygenated VOCs, aromatics, fatty acid oxidation products, which can be emitted by plants. Here we investigate the linkage between VOC emissions, CO2 fluxes and associated isotope effects based on simultaneous real-time measurements of stable carbon isotope composition of branch respired CO2 (CRDS) and VOC fluxes (PTR-MS). We utilized positionally specific 13C-labeled pyruvate branch feeding experiments in the mediterranean shrub (Halimium halimifolium) to trace the partitioning of C1, C2, and C3 carbon atoms of pyruvate into VOCs versus CO2 emissions in the light and in the dark. In the light, we found high emission rates of a large array of VOC including volatile isoprenoids, oxygenated VOCs, green leaf volatiles, aromatics, sulfides, and nitrogen containing VOCs. These observations suggest that in the light, H. halimifolium dedicates a high carbon flux through secondary biosynthetic pathways including the pyruvate dehydrogenase bypass, mevalonic acid, MEP/DOXP, shikimic acid, and

  10. Biogenic volatile organic compound and respiratory CO2 emissions after 13C-labeling: online tracing of C translocation dynamics in poplar plants.

    Science.gov (United States)

    Ghirardo, Andrea; Gutknecht, Jessica; Zimmer, Ina; Brüggemann, Nicolas; Schnitzler, Jörg-Peter

    2011-02-28

    Globally plants are the primary sink of atmospheric CO(2), but are also the major contributor of a large spectrum of atmospheric reactive hydrocarbons such as terpenes (e.g. isoprene) and other biogenic volatile organic compounds (BVOC). The prediction of plant carbon (C) uptake and atmospheric oxidation capacity are crucial to define the trajectory and consequences of global environmental changes. To achieve this, the biosynthesis of BVOC and the dynamics of C allocation and translocation in both plants and ecosystems are important. We combined tunable diode laser absorption spectrometry (TDLAS) and proton transfer reaction mass spectrometry (PTR-MS) for studying isoprene biosynthesis and following C fluxes within grey poplar (Populus x canescens) saplings. This was achieved by feeding either (13)CO(2) to leaves or (13)C-glucose to shoots via xylem uptake. The translocation of (13)CO(2) from the source to other plant parts could be traced by (13)C-labeled isoprene and respiratory (13)CO(2) emission. In intact plants, assimilated (13)CO(2) was rapidly translocated via the phloem to the roots within 1 hour, with an average phloem transport velocity of 20.3±2.5 cm h(-1). (13)C label was stored in the roots and partially reallocated to the plants' apical part one day after labeling, particularly in the absence of photosynthesis. The daily C loss as BVOC ranged between 1.6% in mature leaves and 7.0% in young leaves. Non-isoprene BVOC accounted under light conditions for half of the BVOC C loss in young leaves and one-third in mature leaves. The C loss as isoprene originated mainly (76-78%) from recently fixed CO(2), to a minor extent from xylem-transported sugars (7-11%) and from photosynthetic intermediates with slower turnover rates (8-11%). We quantified the plants' C loss as respiratory CO(2) and BVOC emissions, allowing in tandem with metabolic analysis to deepen our understanding of ecosystem C flux.

  11. Field determination of biomass burning emission ratios and factors via open-path FTIR spectroscopy and fire radiative power assessment: headfire, backfire and residual smouldering combustion in African savannahs

    CSIR Research Space (South Africa)

    Wooster, MJ

    2011-01-01

    Full Text Available Biomass burning emissions factors are vital to quantifying trace gases releases from vegetation fires. Here the authors evaluate emissions factors for a series of savannah fires in Kruger National Park (KNP), South Africa using ground-based open...

  12. Use of Proton-Transfer-Reaction Mass Spectrometry to Characterize Volatile Organic Compound Sources at the La Porte Super Site During the Texas Air Quality Study 2000

    Energy Technology Data Exchange (ETDEWEB)

    Karl, Thomas G.; Jobson, B Tom T.; Kuster, W. C.; Williams, Eric; Stutz, Jochen P.; Shetter, Rick; Hall, Samual R.; Goldan, P. D.; Fehsenfeld, Fred C.; Lindinger, Werner

    2003-08-19

    Proton-transfer-reaction mass spectrometry (PTR-MS) was deployed for continuous real-time monitoring of volatile organic compounds (VOCs) at a site near the Houston Ship Channel during the Texas Air Quality Study 2000. Overall, 28 ions dominated the PTR-MS mass spectra and were assigned as anthropogenic aromatics (e.g., benzene, toluene, xylenes) and hydrocarbons (propene, isoprene), oxygenated compounds (e.g., formaldehyde, acetaldehyde, acetone, methanol, C7 carbonyls), and three nitrogencontaining compounds (e.g., HCN, acetonitrile and acrylonitrile). Biogenic VOCs were minor components at this site. Propene was the most abundant lightweight hydrocarbon detected by this technique with concentrations up to 100+ nmol mol-1, and was highly correlated with its oxidation products, formaldehyde (up to ~40 nmol mol-1) and acetaldehyde (up to ~80 nmol/mol), with typical ratios close to 1 in propene-dominated plumes. In the case of aromatic species the high time resolution of the obtained data set helped in identifying different anthropogenic sources (e.g., industrial from urban emissions) and testing current emission inventories. A comparison with results from complimentary techniques (gas chromatography, differential optical absorption spectroscopy) was used to assess the selectivity of this on-line technique in a complex urban and industrial VOC matrix and give an interpretation of mass scans obtained by ‘‘soft’’ chemical ionization using proton-transfer via H3O+. The method was especially valuable in monitoring rapidly changing VOC plumes which passed over the site, and when coupled with meteorological data it was possible to identify likely sources.

  13. Evidence for the distortion product frequency place as a source of distribution product otoacoustic emission (DPOAE) fine structure in humans : I. Fine structure and higher-order DPOAE as a function of the frequency ratio f2/f1

    NARCIS (Netherlands)

    Mauermann, M; Uppenkamp, S; van Hengel, P.W.J.; Kollmeier, B

    1999-01-01

    Critical experiments were performed in order to validate the two-source hypothesis of distortion product otoacoustic emissions (DPOAE) generation. Measurements of the spectral fine structure of DPOAE in response to stimulation with two sinusoids have been:performed with normal-hearing subjects. The

  14. Air pollution from motor vehicle emissions

    International Nuclear Information System (INIS)

    Petrushevska, Ljubica

    1996-01-01

    This paper presents some aspects of air pollution from motor vehicle emissions as: characteristic primary and secondary pollutants, dependence of the motor vehicle emission from the engine type; the relationship of typical engine emission and performance to air-fuel ratio, transport of pollutants from mobile sources of emissions, as well as some world experiences in the control approaches for exhaust emissions. (author)

  15. Acoustic emission

    International Nuclear Information System (INIS)

    Nichols, R.W.

    1976-01-01

    The volume contains six papers which together provide an overall review of the inspection technique known as acoustic emission or stress wave emission. The titles are: a welder's introduction to acoustic emission technology; use of acoustic emission for detection of defects as they arise during fabrication; examples of laboratory application and assessment of acoustic emission in the United Kingdom; (Part I: acoustic emission behaviour of low alloy steels; Part II: fatigue crack assessment from proof testing and continuous monitoring); inspection of selected areas of engineering structures by acoustic emission; Japanese experience in laboratory and practical applications of acoustic emission to welded structures; and ASME acoustic emission code status. (U.K.)

  16. Financial Key Ratios

    OpenAIRE

    Tănase Alin-Eliodor

    2014-01-01

    This article focuses on computing techniques starting from trial balance data regarding financial key ratios. There are presented activity, liquidity, solvency and profitability financial key ratios. It is presented a computing methodology in three steps based on a trial balance.

  17. VVER-1000 dominance ratio

    International Nuclear Information System (INIS)

    Gorodkov, S.

    2009-01-01

    Dominance ratio, or more precisely, its closeness to unity, is important characteristic of large reactor. It allows evaluate beforehand the number of source iterations required in deterministic calculations of power spatial distribution. Or the minimal number of histories to be modeled for achievement of statistical error level desired in large core Monte Carlo calculations. In this work relatively simple approach for dominance ratio evaluation is proposed. It essentially uses core symmetry. Dependence of dominance ratio on neutron flux spatial distribution is demonstrated. (author)

  18. WWER-1000 dominance ratio

    International Nuclear Information System (INIS)

    Gorodkov, S.S.

    2009-01-01

    Dominance ratio, or more precisely, its closeness to unity, is important characteristic of large reactor. It allows evaluate beforehand the number of source iterations required in deterministic calculations of power spatial distribution. Or the minimal number of histories to be modeled for achievement of statistical error level desired in large core Monte Carlo calculations. In this work relatively simple approach for dominance ratio evaluation is proposed. It essentially uses core symmetry. Dependence of dominance ratio on neutron flux spatial distribution is demonstrated. (Authors)

  19. Sharpening Sharpe Ratios

    OpenAIRE

    William N. Goetzmann; Jonathan E. Ingersoll Jr.; Matthew I. Spiegel; Ivo Welch

    2002-01-01

    It is now well known that the Sharpe ratio and other related reward-to-risk measures may be manipulated with option-like strategies. In this paper we derive the general conditions for achieving the maximum expected Sharpe ratio. We derive static rules for achieving the maximum Sharpe ratio with two or more options, as well as a continuum of derivative contracts. The optimal strategy has a truncated right tail and a fat left tail. We also derive dynamic rules for increasing the Sharpe ratio. O...

  20. Routine Isotopic Analysis of 235U by Emission Spectrometry. 1. Interferometry using electrode-less discharge lamps 2. determination of the 235U/238U ratio using a spectrograph and electrode-less lamps

    International Nuclear Information System (INIS)

    Capitini, R.; Ceccaldi, M.; Leicknam, J.P.; Rabec, J.

    1968-01-01

    I. A 'HYPEAC' interferometric apparatus has been used for routine determination of uranium 235. In order to facilitate the examination of non-metallic samples and to reduce the time required for analysis it has been necessary to replace the hollow-cathode light sources usually used by electrode-less discharge lamps. The preparation outside the apparatus of such lamps containing uranium tetrachloride is described; the process is simple and rapid: about ninety minutes for each, and several lamps can be built simultaneously, thus reducing still further the total time required for each analysis. The amount of sample required is about a few milligrams. In order to counteract any spontaneous optical dis-adjustment which could prevent the application of the usual isotopic abundance method, it is necessary to compare the sample spectra with those of standards, all these spectra being recorded successively and alternately. A series of examples of determinations involving over 150 measurements is presented and discussed. For samples with abundances similar to that of natural uranium and up to 5 per cent of the 235 isotope., the reproducibility is of the order of 2 per cent, the relative accuracy being ± 2 to 3 per cent; for samples enriched in uranium 235 (5 to 93 per cent) the relative accuracy can attain ± 0.5 per cent. II. In spite of the large amount of research into the improvement of the accuracy of uranium isotope analyses using optical methods, it has not been possible up to the present to develop a method as good as mass spectrometry. When it is not necessary to have a high accuracy, however, emission spectroscopy which has no memory effect can constitute a complementary method of analysis if it is sufficiently fast and economical; for this to happen it seems to us that it should be possible to apply such a method in laboratories equipped with all the usual spectrochemical analysis equipment. In the present work we have therefore set out to obtain an acceptable

  1. Detecting isotopic ratio outliers

    International Nuclear Information System (INIS)

    Bayne, C.K.; Smith, D.H.

    1985-01-01

    An alternative method is proposed for improving isotopic ratio estimates. This method mathematically models pulse-count data and uses iterative reweighted Poisson regression to estimate model parameters to calculate the isotopic ratios. This computer-oriented approach provides theoretically better methods than conventional techniques to establish error limits and to identify outliers. 6 refs., 3 figs., 3 tabs

  2. Detecting isotopic ratio outliers

    Science.gov (United States)

    Bayne, C. K.; Smith, D. H.

    An alternative method is proposed for improving isotopic ratio estimates. This method mathematically models pulse-count data and uses iterative reweighted Poisson regression to estimate model parameters to calculate the isotopic ratios. This computer-oriented approach provides theoretically better methods than conventional techniques to establish error limits and to identify outliers.

  3. Detecting isotopic ratio outliers

    International Nuclear Information System (INIS)

    Bayne, C.K.; Smith, D.H.

    1986-01-01

    An alternative method is proposed for improving isotopic ratio estimates. This method mathematically models pulse-count data and uses iterative reweighted Poisson regression to estimate model parameters to calculate the isotopic ratios. This computer-oriented approach provides theoretically better methods than conventional techniques to establish error limits and to identify outliers

  4. Difference and ratio plots

    DEFF Research Database (Denmark)

    Svendsen, Anders Jørgen; Holmskov, U; Bro, Peter

    1995-01-01

    and systemic lupus erythematosus from another previously published study (Macanovic, M. and Lachmann, P.J. (1979) Clin. Exp. Immunol. 38, 274) are also represented using ratio plots. Our observations indicate that analysis by regression analysis may often be misleading....... hitherto unnoted differences between controls and patients with either rheumatoid arthritis or systemic lupus erythematosus. For this we use simple, but unconventional, graphic representations of the data, based on difference plots and ratio plots. Differences between patients with Burkitt's lymphoma...

  5. Emissions Trading

    NARCIS (Netherlands)

    Woerdman, Edwin; Backhaus, Juergen

    2014-01-01

    Emissions trading is a market-based instrument to achieve environmental targets in a cost-effective way by allowing legal entities to buy and sell emission rights. The current international dissemination and intended linking of emissions trading schemes underlines the growing relevance of this

  6. Emission Facilities - Air Emission Plants

    Data.gov (United States)

    NSGIC Education | GIS Inventory — Represents the Primary Facility type Air Emission Plant (AEP) point features. Air Emissions Plant is a DEP primary facility type related to the Air Quality Program....

  7. Emission inventory; Inventaire des emissions

    Energy Technology Data Exchange (ETDEWEB)

    Fontelle, J.P. [CITEPA, Centre Interprofessionnel Technique d`Etudes de la Pollution Atmospherique, 75 - Paris (France)

    1997-12-31

    Statistics on air pollutant (sulfur dioxide, nitrogen oxides and ammonium) emissions, acid equivalent emissions and their evolution since 1990 in the various countries of Europe and the USA, are presented. Emission data from the industrial, agricultural, transportation and power sectors are given, and comparisons are carried out between countries based on Gnp and population, pollution import/export fluxes and compliance to the previous emission reduction objectives

  8. The rectilinear Steiner ratio

    Directory of Open Access Journals (Sweden)

    PO de Wet

    2005-06-01

    Full Text Available The rectilinear Steiner ratio was shown to be 3/2 by Hwang [Hwang FK, 1976, On Steiner minimal trees with rectilinear distance, SIAM Journal on Applied Mathematics, 30, pp. 104– 114.]. We use continuity and introduce restricted point sets to obtain an alternative, short and self-contained proof of this result.

  9. Concentrations and fluxes of biogenic volatile organic compounds above a Mediterranean macchia ecosystem in western Italy

    Directory of Open Access Journals (Sweden)

    B. Davison

    2009-08-01

    Full Text Available Emission rates and concentrations of biogenic volatile organic compounds (BVOCs were measured at a Mediterranean coastal site at Castelporziano, approximately 25 km south-west of Rome, between 7 May and 3 June 2007, as part of the ACCENT-VOCBAS field campaign on biosphere–atmosphere interactions. Concentrations and emission rates were measured using the disjunct eddy covariance (DEC method utilizing three different proton transfer reaction mass spectrometers (PTR-MS so allowing a comparison between the instruments. The high resolution data from the PTR-MS instruments considerably enhances the original BEMA measurements of the mid 1990s.

    Depending on the measurement period, the volume mixing ratios were in the range 1.6–3.5 ppbv for methanol, 0.44–1.3 ppbv for acetaldehyde, 0.96–2.1 ppbv for acetone, 0.10–0.14 ppbv for isoprene, and 0.13–0.30 ppbv for monoterpenes. A diurnal cycle in mixing ratios was apparent with daytime maxima for methanol, acetaldehyde, acetone, and isoprene. The fluxes ranged from 370–440 μg m−2 h−1 for methanol, 180–360 μg m−2 h−1 for acetaldehyde, 180–450 μg m−2 h−1 for acetone, 71–290 μg m−2 h−1 for isoprene, and 240–860 μg m−2 h−1 for monoterpenes. From the measured flux data (7 May–3 June an average basal emission rate for the Macchia vegetation was calculated of 430 μg m−2 h−1 for isoprene and 1100 μg m−2 h−1 for monoterpenes.

  10. Implications of Fast Reactor Transuranic Conversion Ratio

    International Nuclear Information System (INIS)

    Piet, Steven J.; Hoffman, Edward A.; Bays, Samuel E.

    2010-01-01

    Theoretically, the transuranic conversion ratio (CR), i.e. the transuranic production divided by transuranic destruction, in a fast reactor can range from near zero to about 1.9, which is the average neutron yield from Pu239 minus 1. In practice, the possible range will be somewhat less. We have studied the implications of transuranic conversion ratio of 0.0 to 1.7 using the fresh and discharge fuel compositions calculated elsewhere. The corresponding fissile breeding ratio ranges from 0.2 to 1.6. The cases below CR=1 ('burners') do not have blankets; the cases above CR=1 ('breeders') have breeding blankets. The burnup was allowed to float while holding the maximum fluence to the cladding constant. We graph the fuel burnup and composition change. As a function of transuranic conversion ratio, we calculate and graph the heat, gamma, and neutron emission of fresh fuel; whether the material is 'attractive' for direct weapon use using published criteria; the uranium utilization and rate of consumption of natural uranium; and the long-term radiotoxicity after fuel discharge. For context, other cases and analyses are included, primarily once-through light water reactor (LWR) uranium oxide fuel at 51 MWth-day/kg-iHM burnup (UOX-51). For CR 1, heat, gamma, and neutron emission decrease with recycling. The uranium utilization exceeds 1%, especially as all the transuranic elements are recycled. exceeds 1%, especially as all the transuranic elements are recycled. At the system equilibrium, heat and gamma vary by somewhat over an order of magnitude as a function of CR. Isotopes that dominate heat and gamma emission are scattered throughout the actinide chain, so the modest impact of CR is unsurprising. Neutron emitters are preferentially found among the higher actinides, so the neutron emission varies much stronger with CR, about three orders of magnitude.

  11. Transformer ratio enhancement experiment

    International Nuclear Information System (INIS)

    Gai, W.; Power, J. G.; Kanareykin, A.; Neasheva, E.; Altmark, A.

    2004-01-01

    Recently, a multibunch scheme for efficient acceleration based on dielectric wakefield accelerator technology was outlined in J.G. Power, W. Gai, A. Kanareykin, X. Sun. PAC 2001 Proceedings, pp. 114-116, 2002. In this paper we present an experimental program for the design, development and demonstration of an Enhanced Transformer Ratio Dielectric Wakefield Accelerator (ETR-DWA). The principal goal is to increase the transformer ratio R, the parameter that characterizes the energy transfer efficiency from the accelerating structure to the accelerated electron beam. We present here an experimental design of a 13.625 GHz dielectric loaded accelerating structure, a laser multisplitter producing a ramped bunch train, and simulations of the bunch train parameters required. Experimental results of the accelerating structure bench testing and ramped pulsed train generation with the laser multisplitter are shown as well. Using beam dynamic simulations, we also obtain the focusing FODO lattice parameters

  12. Intake to Production Ratio

    DEFF Research Database (Denmark)

    Nazaroff, William; Weschler, Charles J.; Little, John C.

    2012-01-01

    BACKGROUND: Limited data are available to assess human exposure to thousands of chemicals currently in commerce. Information that relates human intake of a chemical to its production and use can help inform understanding of mechanisms and pathways that control exposure and support efforts...... to protect public health.OBJECTIVES: We introduce the intake-to-production ratio (IPR) as an economy-wide quantitative indicator of the extent to which chemical production results in human exposure.METHODS: The IPR was evaluated as the ratio of two terms: aggregate rate of chemical uptake in a human......(n-butyl) phthalate, 1,040 ppm for para-dichlorobenzene, 6,800 ppm for di(isobutyl) phthalate, 7,700 ppm for diethyl phthalate, and 8,000-24,000 ppm (range) for triclosan.CONCLUSION: The IPR is well suited as an aggregate metric of exposure intensity for characterizing population-level exposure to synthesized...

  13. A novel fast gas chromatography method for higher time resolution measurements of speciated monoterpenes in air

    Science.gov (United States)

    Jones, C. E.; Kato, S.; Nakashima, Y.; Kajii, Y.

    2014-05-01

    ~30 km west of central Tokyo, Japan, the Fast-GC limit of detection with respect to monoterpenes was 4-5 ppt, and the agreement between Fast-GC and PTR-MS derived total monoterpene mixing ratios was consistent with previous GC/PTR-MS comparisons. The measurement uncertainties associated with the Fast-GC quantification of monoterpenes are ≤ 12%, while larger uncertainties (up to ~25%) are associated with the OBVOC and sesquiterpene measurements.

  14. A novel Fast Gas Chromatography based technique for higher time resolution measurements of speciated monoterpenes in air

    Science.gov (United States)

    Jones, C. E.; Kato, S.; Nakashima, Y.; Kajii, Y.

    2013-12-01

    Fast-GC limit of detection with respect to monoterpenes was 4-5 ppt, and the agreement between Fast-GC and PTR-MS derived total monoterpene mixing ratios was consistent with previous GC/PTR-MS comparisons. The measurement uncertainties associated with the Fast-GC quantification of monoterpenes are ≤ 10%, while larger uncertainties (up to ~ 25%) are associated with the OBVOC and sesquiterpene measurements.

  15. The Reference Return Ratio

    DEFF Research Database (Denmark)

    Nicolaisen, Jeppe; Faber Frandsen, Tove

    2008-01-01

    The paper introduces a new journal impact measure called The Reference Return Ratio (3R). Unlike the traditional Journal Impact Factor (JIF), which is based on calculations of publications and citations, the new measure is based on calculations of bibliographic investments (references) and returns...... (citations). A comparative study of the two measures shows a strong relationship between the 3R and the JIF. Yet, the 3R appears to correct for citation habits, citation dynamics, and composition of document types - problems that typically are raised against the JIF. In addition, contrary to traditional...

  16. Potential support ratios

    DEFF Research Database (Denmark)

    Kjærgaard, Søren; Canudas-Romo, Vladimir

    2017-01-01

    The ‘prospective potential support ratio’ has been proposed by researchers as a measure that accurately quantifies the burden of ageing, by identifying the fraction of a population that has passed a certain measure of longevity, for example, 17 years of life expectancy. Nevertheless......, the prospective potential support ratio usually focuses on the current mortality schedule, or period life expectancy. Instead, in this paper we look at the actual mortality experienced by cohorts in a population, using cohort life tables. We analyse differences between the two perspectives using mortality models...

  17. Tau hadronic branching ratios

    CERN Document Server

    Buskulic, Damir; De Bonis, I; Décamp, D; Ghez, P; Goy, C; Lees, J P; Lucotte, A; Minard, M N; Odier, P; Pietrzyk, B; Ariztizabal, F; Chmeissani, M; Crespo, J M; Efthymiopoulos, I; Fernández, E; Fernández-Bosman, M; Gaitan, V; Martínez, M; Orteu, S; Pacheco, A; Padilla, C; Palla, Fabrizio; Pascual, A; Perlas, J A; Sánchez, F; Teubert, F; Colaleo, A; Creanza, D; De Palma, M; Farilla, A; Gelao, G; Girone, M; Iaselli, Giuseppe; Maggi, G; Maggi, M; Marinelli, N; Natali, S; Nuzzo, S; Ranieri, A; Raso, G; Romano, F; Ruggieri, F; Selvaggi, G; Silvestris, L; Tempesta, P; Zito, G; Huang, X; Lin, J; Ouyang, Q; Wang, T; Xie, Y; Xu, R; Xue, S; Zhang, J; Zhang, L; Zhao, W; Bonvicini, G; Cattaneo, M; Comas, P; Coyle, P; Drevermann, H; Engelhardt, A; Forty, Roger W; Frank, M; Hagelberg, R; Harvey, J; Jacobsen, R; Janot, P; Jost, B; Kneringer, E; Knobloch, J; Lehraus, Ivan; Markou, C; Martin, E B; Mato, P; Minten, Adolf G; Miquel, R; Oest, T; Palazzi, P; Pater, J R; Pusztaszeri, J F; Ranjard, F; Rensing, P E; Rolandi, Luigi; Schlatter, W D; Schmelling, M; Schneider, O; Tejessy, W; Tomalin, I R; Venturi, A; Wachsmuth, H W; Wiedenmann, W; Wildish, T; Witzeling, W; Wotschack, J; Ajaltouni, Ziad J; Bardadin-Otwinowska, Maria; Barrès, A; Boyer, C; Falvard, A; Gay, P; Guicheney, C; Henrard, P; Jousset, J; Michel, B; Monteil, S; Pallin, D; Perret, P; Podlyski, F; Proriol, J; Rossignol, J M; Saadi, F; Fearnley, Tom; Hansen, J B; Hansen, J D; Hansen, J R; Hansen, P H; Nilsson, B S; Kyriakis, A; Simopoulou, Errietta; Siotis, I; Vayaki, Anna; Zachariadou, K; Blondel, A; Bonneaud, G R; Brient, J C; Bourdon, P; Passalacqua, L; Rougé, A; Rumpf, M; Tanaka, R; Valassi, Andrea; Verderi, M; Videau, H L; Candlin, D J; Parsons, M I; Focardi, E; Parrini, G; Corden, M; Delfino, M C; Georgiopoulos, C H; Jaffe, D E; Antonelli, A; Bencivenni, G; Bologna, G; Bossi, F; Campana, P; Capon, G; Chiarella, V; Felici, G; Laurelli, P; Mannocchi, G; Murtas, F; Murtas, G P; Pepé-Altarelli, M; Dorris, S J; Halley, A W; ten Have, I; Knowles, I G; Lynch, J G; Morton, W T; O'Shea, V; Raine, C; Reeves, P; Scarr, J M; Smith, K; Smith, M G; Thompson, A S; Thomson, F; Thorn, S; Turnbull, R M; Becker, U; Braun, O; Geweniger, C; Graefe, G; Hanke, P; Hepp, V; Kluge, E E; Putzer, A; Rensch, B; Schmidt, M; Sommer, J; Stenzel, H; Tittel, K; Werner, S; Wunsch, M; Beuselinck, R; Binnie, David M; Cameron, W; Colling, D J; Dornan, Peter J; Konstantinidis, N P; Moneta, L; Moutoussi, A; Nash, J; San Martin, G; Sedgbeer, J K; Stacey, A M; Dissertori, G; Girtler, P; Kuhn, D; Rudolph, G; Bowdery, C K; Brodbeck, T J; Colrain, P; Crawford, G; Finch, A J; Foster, F; Hughes, G; Sloan, Terence; Whelan, E P; Williams, M I; Galla, A; Greene, A M; Kleinknecht, K; Quast, G; Raab, J; Renk, B; Sander, H G; Wanke, R; Van Gemmeren, P; Zeitnitz, C; Aubert, Jean-Jacques; Bencheikh, A M; Benchouk, C; Bonissent, A; Bujosa, G; Calvet, D; Carr, J; Diaconu, C A; Etienne, F; Thulasidas, M; Nicod, D; Payre, P; Rousseau, D; Talby, M; Abt, I; Assmann, R W; Bauer, C; Blum, Walter; Brown, D; Dietl, H; Dydak, Friedrich; Ganis, G; Gotzhein, C; Jakobs, K; Kroha, H; Lütjens, G; Lutz, Gerhard; Männer, W; Moser, H G; Richter, R H; Rosado-Schlosser, A; Schael, S; Settles, Ronald; Seywerd, H C J; Saint-Denis, R; Wolf, G; Alemany, R; Boucrot, J; Callot, O; Cordier, A; Courault, F; Davier, M; Duflot, L; Grivaz, J F; Heusse, P; Jacquet, M; Kim, D W; Le Diberder, F R; Lefrançois, J; Lutz, A M; Musolino, G; Nikolic, I A; Park, H J; Park, I C; Schune, M H; Simion, S; Veillet, J J; Videau, I; Abbaneo, D; Azzurri, P; Bagliesi, G; Batignani, G; Bettarini, S; Bozzi, C; Calderini, G; Carpinelli, M; Ciocci, M A; Ciulli, V; Dell'Orso, R; Fantechi, R; Ferrante, I; Foà, L; Forti, F; Giassi, A; Giorgi, M A; Gregorio, A; Ligabue, F; Lusiani, A; Marrocchesi, P S; Messineo, A; Rizzo, G; Sanguinetti, G; Sciabà, A; Spagnolo, P; Steinberger, Jack; Tenchini, Roberto; Tonelli, G; Triggiani, G; Vannini, C; Verdini, P G; Walsh, J; Betteridge, A P; Blair, G A; Bryant, L M; Cerutti, F; Gao, Y; Green, M G; Johnson, D L; Medcalf, T; Mir, L M; Perrodo, P; Strong, J A; Bertin, V; Botterill, David R; Clifft, R W; Edgecock, T R; Haywood, S; Edwards, M; Maley, P; Norton, P R; Thompson, J C; Bloch-Devaux, B; Colas, P; Emery, S; Kozanecki, Witold; Lançon, E; Lemaire, M C; Locci, E; Marx, B; Pérez, P; Rander, J; Renardy, J F; Roussarie, A; Schuller, J P; Schwindling, J; Trabelsi, A; Vallage, B; Johnson, R P; Kim, H Y; Litke, A M; McNeil, M A; Taylor, G; Beddall, A; Booth, C N; Boswell, R; Cartwright, S L; Combley, F; Dawson, I; Köksal, A; Letho, M; Newton, W M; Rankin, C; Thompson, L F; Böhrer, A; Brandt, S; Cowan, G D; Feigl, E; Grupen, Claus; Lutters, G; Minguet-Rodríguez, J A; Rivera, F; Saraiva, P; Smolik, L; Stephan, F; Apollonio, M; Bosisio, L; Della Marina, R; Giannini, G; Gobbo, B; Ragusa, F; Rothberg, J E; Wasserbaech, S R; Armstrong, S R; Bellantoni, L; Elmer, P; Feng, Z; Ferguson, D P S; Gao, Y S; González, S; Grahl, J; Harton, J L; Hayes, O J; Hu, H; McNamara, P A; Nachtman, J M; Orejudos, W; Pan, Y B; Saadi, Y; Schmitt, M; Scott, I J; Sharma, V; Turk, J; Walsh, A M; Wu Sau Lan; Wu, X; Yamartino, J M; Zheng, M; Zobernig, G

    1996-01-01

    From 64492 selected \\tau-pair events, produced at the Z^0 resonance, the measurement of the tau decays into hadrons from a global analysis using 1991, 1992 and 1993 ALEPH data is presented. Special emphasis is given to the reconstruction of photons and \\pi^0's, and the removal of fake photons. A detailed study of the systematics entering the \\pi^0 reconstruction is also given. A complete and consistent set of tau hadronic branching ratios is presented for 18 exclusive modes. Most measurements are more precise than the present world average. The new level of precision reached allows a stringent test of \\tau-\\mu universality in hadronic decays, g_\\tau/g_\\mu \\ = \\ 1.0013 \\ \\pm \\ 0.0095, and the first measurement of the vector and axial-vector contributions to the non-strange hadronic \\tau decay width: R_{\\tau ,V} \\ = \\ 1.788 \\ \\pm \\ 0.025 and R_{\\tau ,A} \\ = \\ 1.694 \\ \\pm \\ 0.027. The ratio (R_{\\tau ,V} - R_{\\tau ,A}) / (R_{\\tau ,V} + R_{\\tau ,A}), equal to (2.7 \\pm 1.3) \\ \\%, is a measure of the importance of Q...

  18. Peak power ratio generator

    Science.gov (United States)

    Moyer, R.D.

    A peak power ratio generator is described for measuring, in combination with a conventional power meter, the peak power level of extremely narrow pulses in the gigahertz radio frequency bands. The present invention in a preferred embodiment utilizes a tunnel diode and a back diode combination in a detector circuit as the only high speed elements. The high speed tunnel diode provides a bistable signal and serves as a memory device of the input pulses for the remaining, slower components. A hybrid digital and analog loop maintains the peak power level of a reference channel at a known amount. Thus, by measuring the average power levels of the reference signal and the source signal, the peak power level of the source signal can be determined.

  19. The Liquidity Coverage Ratio: the need for further complementary ratios?

    OpenAIRE

    Ojo, Marianne

    2013-01-01

    This paper considers components of the Liquidity Coverage Ratio – as well as certain prevailing gaps which may necessitate the introduction of a complementary liquidity ratio. The definitions and objectives accorded to the Liquidity Coverage Ratio (LCR) and Net Stable Funding Ratio (NSFR) highlight the focus which is accorded to time horizons for funding bank operations. A ratio which would focus on the rate of liquidity transformations and which could also serve as a complementary metric gi...

  20. Mixing ratio sensor of alcohol mixed fuel

    Energy Technology Data Exchange (ETDEWEB)

    Miyata, Shigeru; Matsubara, Yoshihiro

    1987-08-07

    In order to improve combustion efficiency of an internal combustion engine using gasoline-alcohol mixed fuel and to reduce harmful substance in its exhaust gas, it is necessary to control strictly the air-fuel ratio to be supplied and the ignition timing and change the condition of control depending upon the mixing ratio of the mixed fuel. In order to detect the mixing ratio of the mixed fuel, the above mixing ratio has so far been detected by casting a ray of light to the mixed fuel and utilizing a change of critical angle associated with the change of the composition of the fluid of the mixed fuel. However, in case when a light emitting diode is used for the light source above, two kinds of sensors are further needed. Concerning the two kinds of sensors above, this invention offers a mixing ratio sensor for the alcohol mixed fuel which can abolish a temperature sensor to detect the environmental temperature by making a single compensatory light receiving element deal with the compensation of the amount of light emission of the light emitting element due to the temperature change and the compensation of the critical angle caused by the temperature change. (6 figs)

  1. Energy Profit Ratio Compared

    International Nuclear Information System (INIS)

    Amano, Osamu

    2007-01-01

    We need more oil energy to take out oil under the ground. Limit resources make us consider other candidates of energy source instead of oil. Electricity shall be the main role more and more like electric vehicles and air conditioners so we should consider electricity generation ways. When we consider what kind of electric power generation is the best or suitable, we should not only power generation plant but whole process from mining to power generation. It is good way to use EPR, Energy Profit Ratio, to analysis which type is more efficient and which part is to do research and development when you see the input breakdown analysis. Electricity by the light water nuclear power plant, the hydrogen power plant and the geothermal power plant are better candidates from EPR analysis. Forecasting the world primly energy supply in 2050, it is said that the demand will be double of the demand in 2000 and the supply will not be able to satisfy the demand in 2050. We should save 30% of the demand and increase nuclear power plants 3.5 times more and recyclable energy like hydropower plants 3 times more. When the nuclear power plants are 3.5 times more then uranium peak will come and we will need breed uranium. I will analysis the EPR of FBR. Conclusion: A) the EPR of NPS in Japan is 17.4 and it is the best of all. B) Many countries will introduce new nuclear power plants rapidly may be 3.5 times in 2050. C) Uranium peak will happen around 2050. (author)

  2. Acoustic emission

    International Nuclear Information System (INIS)

    Straus, A.; Lopez Pumarega, M.I.; Di Gaetano, J.O.; D'Atellis, C.E.; Ruzzante, J.E.

    1990-01-01

    This paper is related to our activities on acoustic emission (A.E.). The work is made with different materials: metals and fibre reinforced plastics. At present, acoustic emission transducers are being developed for low and high temperature. A test to detect electrical discharges in electrical transformers was performed. Our experience in industrial tests to detect cracks or failures in tanks or tubes is also described. The use of A.E. for leak detection is considered. Works on pattern recognition of A.E. signals are also being performed. (Author)

  3. CO line ratios in molecular clouds: the impact of environment

    Science.gov (United States)

    Peñaloza, Camilo H.; Clark, Paul C.; Glover, Simon C. O.; Klessen, Ralf S.

    2018-04-01

    Line emission is strongly dependent on the local environmental conditions in which the emitting tracers reside. In this work, we focus on modelling the CO emission from simulated giant molecular clouds (GMCs), and study the variations in the resulting line ratios arising from the emission from the J = 1-0, J = 2-1, and J = 3-2 transitions. We perform a set of smoothed particle hydrodynamics simulations with time-dependent chemistry, in which environmental conditions - including total cloud mass, density, size, velocity dispersion, metallicity, interstellar radiation field (ISRF), and the cosmic ray ionization rate (CRIR) - were systematically varied. The simulations were then post-processed using radiative transfer to produce synthetic emission maps in the three transitions quoted above. We find that the cloud-averaged values of the line ratios can vary by up to ±0.3 dex, triggered by changes in the environmental conditions. Changes in the ISRF and/or in the CRIR have the largest impact on line ratios since they directly affect the abundance, temperature, and distribution of CO-rich gas within the clouds. We show that the standard methods used to convert CO emission to H2 column density can underestimate the total H2 molecular gas in GMCs by factors of 2 or 3, depending on the environmental conditions in the clouds.

  4. Large Aspect Ratio Tokamak Study

    International Nuclear Information System (INIS)

    Reid, R.L.; Holmes, J.A.; Houlberg, W.A.; Peng, Y.K.M.; Strickler, D.J.; Brown, T.G.; Wiseman, G.W.

    1980-06-01

    The Large Aspect Ratio Tokamak Study (LARTS) at Oak Ridge National Laboratory (ORNL) investigated the potential for producing a viable longburn tokamak reactor by enhancing the volt-second capability of the ohmic heating transformer through the use of high aspect ratio designs. The plasma physics, engineering, and economic implications of high aspect ratio tokamaks were assessed in the context of extended burn operation. Using a one-dimensional transport code plasma startup and burn parameters were addressed. The pulsed electrical power requirements for the poloidal field system, which have a major impact on reactor economics, were minimized by optimizing the startup and shutdown portions of the tokamak cycle. A representative large aspect ratio tokamak with an aspect ratio of 8 was found to achieve a burn time of 3.5 h at capital cost only approx. 25% greater than that of a moderate aspect ratio design tokamak

  5. Sex Ratio Elasticity Influences the Selection of Sex Ratio Strategy

    Science.gov (United States)

    Wang, Yaqiang; Wang, Ruiwu; Li, Yaotang; (Sam) Ma, Zhanshan

    2016-12-01

    There are three sex ratio strategies (SRS) in nature—male-biased sex ratio, female-biased sex ratio and, equal sex ratio. It was R. A. Fisher who first explained why most species in nature display a sex ratio of ½. Consequent SRS theories such as Hamilton’s local mate competition (LMC) and Clark’s local resource competition (LRC) separately explained the observed deviations from the seemingly universal 1:1 ratio. However, to the best of our knowledge, there is not yet a unified theory that accounts for the mechanisms of the three SRS. Here, we introduce the price elasticity theory in economics to define sex ratio elasticity (SRE), and present an analytical model that derives three SRSs based on the following assumption: simultaneously existing competitions for both resources A and resources B influence the level of SRE in both sexes differently. Consequently, it is the difference (between two sexes) in the level of their sex ratio elasticity that leads to three different SRS. Our analytical results demonstrate that the elasticity-based model not only reveals a highly plausible mechanism that explains the evolution of SRS in nature, but also offers a novel framework for unifying two major classical theories (i.e., LMC & LRC) in the field of SRS research.

  6. On-road emissions of ammonia: An underappreciated source of atmospheric nitrogen deposition

    Science.gov (United States)

    Mark E. Fenn; Andrzej Bytnerowicz; Susan L. Schilling; Dena M. Vallano; Erika S. Zavaleta; Stuart B. Weiss; Connor Morozumi; Linda H. Geiser; Kenneth Hanks

    2018-01-01

    We provide updated spatial distribution and inventory data for on-road NH3 emissions for the continental United States (U.S.) On-road NH3 emissions were determined from on-road CO2 emissions data and empirical NH3:CO2 vehicle emissions ratios. Emissions of...

  7. Cold versus hot fusion deuterium branching ratios

    International Nuclear Information System (INIS)

    Fox, H.; Bass, R.

    1995-01-01

    A major source of misunderstanding of the nature of cold nuclear fusion has been the expectation that the deuterium branching ratios occurring within a palladium lattice would be consistent with the gas-plasma branching ratios. This misunderstanding has led to the concept of the dead graduate student, the 1989's feverish but fruitless search for neutron emissions from cold fusion reactors, and the follow-on condemnation of the new science of cold fusion. The experimental facts are that in a properly loaded palladium lattice, the deuterium fusion produces neutrons at little above background, a greatly less-than-expected production of tritium (the tritium desert), and substantially more helium-4 than is observed in hot plasma physics. The experimental evidence is now compelling (800 reports of success from 30 countries) that cold nuclear fusion is a reality, that the branching ratios are unexpected, and that a new science is struggling to be recognized. Commercialization of some types of cold fusion devices has already begun

  8. Holes at High Blowing Ratios

    Directory of Open Access Journals (Sweden)

    Phillip M. Ligrani

    1996-01-01

    Full Text Available Experimental results are presented which describe the development and structure of flow downstream of a single row of holes with compound angle orientations producing film cooling at high blowing ratios. This film cooling configuration is important because similar arrangements are frequently employed on the first stage of rotating blades of operating gas turbine engines. With this configuration, holes are spaced 6d apart in the spanwise direction, with inclination angles of 24 degrees, and angles of orientation of 50.5 degrees. Blowing ratios range from 1.5 to 4.0 and the ratio of injectant to freestream density is near 1.0. Results show that spanwise averaged adiabatic effectiveness, spanwise-averaged iso-energetic Stanton number ratios, surveys of streamwise mean velocity, and surveys of injectant distributions change by important amounts as the blowing ratio increases. This is due to injectant lift-off from the test surface just downstream of the holes.

  9. Time resolved investigations on biogenic trace gases exchanges using proton-transfer-reaction mass spectrometry

    International Nuclear Information System (INIS)

    Karl, T.

    2000-02-01

    Volatile organic compounds (VOCs) released from vegetation, including wound-induced VOCs, can have important effects on atmospheric chemistry. The analytical methods for measuring wound-induced VOCs, especially the hexenal family of VOCs (hexenals, hexenols and hexenyl esters) but also compounds like acetaldehyde, are complicated by their chemical instability and the transient nature of their formation after leaf and stem wounding. The goal of this thesis was to assess, quantify and complement our understanding on the origin of tropospheric VOCs. This thesis demonstrates that formation and emission of hexenal family compounds can be monitored on-line using proton-transfer-reaction mass spectrometry (PTR-MS), avoiding the need for preconcentration or chromatography. These measurements revealed the rapid emission of the parent compound, (Z)-3-hexenal, within 1-2 seconds of wounding of leaves from various woody and nonwoody plants, and its metabolites including (E)-2-hexenal, hexenols and hexenyl acetates. Emission of (Z)-3-hexenal from detached, drying leaves averaged 500 μg (gram dry weight)-1. PTR-MS showed to be a useful tool for the analysis of VOC emissions resulting from grazing, herbivory, harvesting and senescing leaves. The release of reactive VOCs during lawn mowing was observed in on-line ambient air measurements in July and August 1998 in the outskirts of Innsbruck. Also obtained were data on emission rates of reactive aldehydes (hexenyl compounds) and other abundant VOCs such as methanol, acetaldehyde and acetone from drying grass in various chamber experiments. Fluxes were measured after cutting of grass using eddy covariance measurements and the micrometeorological gradient method (Obhukov-Similarity-Method). Comparison of data obtained by these different methods showed satisfactory agreement. The highest fluxes for methanol during drying were 5 mg/m2h, for (Z)-3-hexenal 1.5 mg/m2h. Experiments conducted on the Sonnblick Observatory in Fall and Winter

  10. Deriving aerosol scattering ratio using range-resolved lidar ratio

    Indian Academy of Sciences (India)

    2014-02-13

    Feb 13, 2014 ... ratio (LDR) are used to suggest the type of aerosols. The altitude-dependent ... to the station and the experimentally measured lidar data. The 'model ... The integrated aerosol extinction profile with altitude-dependent S and k.

  11. Enteric methane emissions from German pigs

    DEFF Research Database (Denmark)

    Dämmgen, Ulrich; Schulz, Joachim; Klausing, Heinrich Kleine

    2012-01-01

    Methane emissions from enteric fermentation of pigs are object of emission reporting. Hitherto they were treated as part of the energy balance of pigs, in accordance with IPCC guidance documents. They were calculated from the gross energy intake rate and a constant methane conversion ratio....... Meanwhile numerous experimental data on methane emissions from enteric fermentation is available in Germany and abroad; the results are compiled in this work. These results also allow for a description of transformation processes in the hind gut and a subsequent establishment of models that relate emissions...... to feed and performance data. The model by Kirchgeßner et al. (1995) is based on German experimental data and reflects typical national diet compositions. It is used to quantify typical emissions and methane conversion ratios. The results agree with other experimental findings at home and abroad...

  12. RATIO_TOOL - SOFTWARE FOR COMPUTING IMAGE RATIOS

    Science.gov (United States)

    Yates, G. L.

    1994-01-01

    Geological studies analyze spectral data in order to gain information on surface materials. RATIO_TOOL is an interactive program for viewing and analyzing large multispectral image data sets that have been created by an imaging spectrometer. While the standard approach to classification of multispectral data is to match the spectrum for each input pixel against a library of known mineral spectra, RATIO_TOOL uses ratios of spectral bands in order to spot significant areas of interest within a multispectral image. Each image band can be viewed iteratively, or a selected image band of the data set can be requested and displayed. When the image ratios are computed, the result is displayed as a gray scale image. At this point a histogram option helps in viewing the distribution of values. A thresholding option can then be used to segment the ratio image result into two to four classes. The segmented image is then color coded to indicate threshold classes and displayed alongside the gray scale image. RATIO_TOOL is written in C language for Sun series computers running SunOS 4.0 and later. It requires the XView toolkit and the OpenWindows window manager (version 2.0 or 3.0). The XView toolkit is distributed with Open Windows. A color monitor is also required. The standard distribution medium for RATIO_TOOL is a .25 inch streaming magnetic tape cartridge in UNIX tar format. An electronic copy of the documentation is included on the program media. RATIO_TOOL was developed in 1992 and is a copyrighted work with all copyright vested in NASA. Sun, SunOS, and OpenWindows are trademarks of Sun Microsystems, Inc. UNIX is a registered trademark of AT&T Bell Laboratories.

  13. Field Emission from Carbon Nanostructures

    Directory of Open Access Journals (Sweden)

    Filippo Giubileo

    2018-03-01

    Full Text Available Field emission electron sources in vacuum electronics are largely considered to achieve faster response, higher efficiency and lower energy consumption in comparison with conventional thermionic emitters. Carbon nanotubes had a leading role in renewing attention to field emission technologies in the early 1990s, due to their exceptional electron emitting properties enabled by their large aspect ratio, high electrical conductivity, and thermal and chemical stability. In the last decade, the search for improved emitters has been extended to several carbon nanostructures, comprising carbon nanotubes, either individual or films, diamond structures, graphitic materials, graphene, etc. Here, we review the main results in the development of carbon-based field emitters.

  14. Disjunct eddy covariance measurements of volatile organic compound fluxes using proton transfer reaction mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Taipale, R.

    2011-07-01

    Volatile organic compounds (VOCs) are emitted into the atmosphere from natural and anthropogenic sources, vegetation being the dominant source on a global scale. Some of these reactive compounds are deemed major contributors or inhibitors to aerosol particle formation and growth, thus making VOC measurements essential for current climate change research. This thesis discusses ecosystem scale VOC fluxes measured above a boreal Scots pine dominated forest in southern Finland. The flux measurements were performed using the micrometeorological disjunct eddy covariance (DEC) method combined with proton transfer reaction mass spectrometry (PTR-MS), which is an online technique for measuring VOC concentrations. The measurement, calibration, and calculation procedures developed in this work proved to be well suited to long-term VOC concentration and flux measurements with PTR-MS. A new averaging approach based on running averaged covariance functions improved the determination of the lag time between wind and concentration measurements, which is a common challenge in DEC when measuring fluxes near the detection limit. The ecosystem scale emissions of methanol, acetaldehyde, and acetone were substantial. These three oxygenated VOCs made up about half of the total emissions, with the rest comprised of monoterpenes. Contrary to the traditional assumption that monoterpene emissions from Scots pine originate mainly as evaporation from specialized storage pools, the DEC measurements indicated a significant contribution from de novo biosynthesis to the ecosystem scale monoterpene emissions. This thesis offers practical guidelines for long-term DEC measurements with PTR-MS. In particular, the new averaging approach to the lag time determination seems useful in the automation of DEC flux calculations. Seasonal variation in the monoterpene biosynthesis and the detailed structure of a revised hybrid algorithm, describing both de novo and pool emissions, should be determined in

  15. Ventilation and ventilation/perfusion ratios

    International Nuclear Information System (INIS)

    Valind, S.O.

    1989-01-01

    The thesis is based on five different papers. The labelling of specific tracer compounds with positron emitting radionuclides enables a range of structural, physiological and biochemical parameters in the lung to be measured non-invasively, using positron emission tomography. This concept affords a unique opportunity for in vivo studies of different expressions of pulmonary pathophysiology at the regional level. The present thesis describes the application of positron emission tomography to the measurements of ventilation and ventilation/perfusion ratios using inert gas tracers, neon-19 and nitrogen-13 respectively. The validity of the methods applied was investigated with respect to the transport of inert gas tracers in the human lung. Both ventilation and the ventilation/perfusion ratio may be obtained with errors less than 10 % in the normal lung. In disease, however, errors may increase in those instances where the regional ventilation is very low or the intra-regional gas flow distribution is markedly nonuniform. A 2-3 fold increase in ventilation was demonstrated in normal nonsmoking subjects going from ventral to dorsal regions in the supine posture. These large regional differences could be well explained by the intrinsic elastic properties of lung tissue, considering the gravitational gradient in transpulmonary pressure. In asymptomatic smokers substantial regional ventilatroy abnormalities were found whilst the regional gas volume was similar in smokers and nonsmokers. The uncoupling between ventilation and gas volume probably reflects inflammatory changes in the airways. The regional differences in dV/dt/dQ/dt were relatively small and blood flow was largely matched to ventilation in the supine posture. However, small regions of lung with very low ventilation, unmatched by blood flow commonly exists in the most dependent parts of the lung in both smokers and nonsmokers. (29 illustrations, 7 tables, 113 references)

  16. High ratio recirculating gas compressor

    Science.gov (United States)

    Weinbrecht, J.F.

    1989-08-22

    A high ratio positive displacement recirculating rotary compressor is disclosed. The compressor includes an integral heat exchanger and recirculation conduits for returning cooled, high pressure discharge gas to the compressor housing to reducing heating of the compressor and enable higher pressure ratios to be sustained. The compressor features a recirculation system which results in continuous and uninterrupted flow of recirculation gas to the compressor with no direct leakage to either the discharge port or the intake port of the compressor, resulting in a capability of higher sustained pressure ratios without overheating of the compressor. 10 figs.

  17. Output factors and scatter ratios

    Energy Technology Data Exchange (ETDEWEB)

    Shrivastava, P N; Summers, R E; Samulski, T V; Baird, L C [Allegheny General Hospital, Pittsburgh, PA (USA); Ahuja, A S; Dubuque, G L; Hendee, W R; Chhabra, A S

    1979-07-01

    Reference is made to a previous publication on output factors and scatter ratios for radiotherapy units in which it was suggested that the output factor should be included in the definitions of scatter-air ratio and tissue-maximum ratio. In the present correspondence from other authors and from the authors of the previous publication, the original definitions and the proposed changes are discussed. Radiation scatter from source and collimator degradation of beam energy and calculation of dose in tissue are considered in relation to the objective of accurate dosimetry.

  18. On the mechanism of fission neutron emission

    International Nuclear Information System (INIS)

    Maerten, H.; Richter, D.; Seeliger, D.

    1986-01-01

    This review represents the present knowledge of the mechanism of prompt fission neutron emission. Starting with a brief fission process characterization related with neutron emission, possible emission mechanisms are discussed. It is emphasized that the experimental study of special mechanisms, i.e. scission neutron emission processes, requires a sufficiently correct description of emission probabilities on the base of the main mechanism, i.e. the evaporation from fully accelerated fragments. Adequate statistical-model approaches have to account for the complexity of nuclear fission reflected by an intricate fragment distribution. The present picture of scission neutron emission is not clarified neither experimentally nor theoretically. Deduced data are contradictory and depend on the used analysis procedures often involving rough discriptions of evaporated-neutron distributions. The contribution of two secondary mechanisms of fission neutron emission, i.e. the neutron evaporation during fragment acceleration and neutron emission due to the decay of 5 He after ternary fission, is estimated. We summarize the recent progress of the theoretical description of fission neutron spectra in the framework of statistical models considering the standard spectrum of 252 Cf(sf) neutrons especially. The main experimental basis for the study of fission neutron emission is the accurate measurement of emission probabilities as a function of emission energy and angle (at least) as well as fragment parameters (mass number ratio and kinetic energy). The present status is evaluated. (author)

  19. Large aspect ratio tokamak study

    International Nuclear Information System (INIS)

    Reid, R.L.; Holmes, J.A.; Houlberg, W.A.; Peng, Y.K.M.; Strickler, D.J.; Brown, T.G.; Sardella, C.; Wiseman, G.W.

    1979-01-01

    The Large Aspect Ratio Tokamak Study (LARTS) investigated the potential for producing a viable long burn tokamak reactor through enhanced volt-second capability of the ohmic heating transformer by employing high aspect ratio designs. The plasma physics, engineering, and economic implications of high aspect ratio tokamaks were accessed in the context of extended burn operation. Plasma startup and burn parameters were addressed using a one-dimensional transport code. The pulsed electrical power requirements for the poloidal field system, which have a major impact on reactor economics, were minimized by optimizing the field in the ohmic heating coil and the wave shape of the ohmic heating discharge. A high aspect ratio reference reactor was chosen and configured

  20. Arcjet nozzle area ratio effects

    Science.gov (United States)

    Curran, Francis M.; Sarmiento, Charles J.; Birkner, Bjorn W.; Kwasny, James

    1990-01-01

    An experimental investigation was conducted to determine the effect of nozzle area ratio on the operating characteristics and performance of a low power dc arcjet thruster. Conical thoriated tungsten nozzle inserts were tested in a modular laboratory arcjet thruster run on hydrogen/nitrogen mixtures simulating the decomposition products of hydrazine. The converging and diverging sides of the inserts had half angles of 30 and 20 degrees, respectively, similar to a flight type unit currently under development. The length of the diverging side was varied to change the area ratio. The nozzle inserts were run over a wide range of specific power. Current, voltage, mass flow rate, and thrust were monitored to provide accurate comparisons between tests. While small differences in performance were observed between the two nozzle inserts, it was determined that for each nozzle insert, arcjet performance improved with increasing nozzle area ratio to the highest area ratio tested and that the losses become very pronounced for area ratios below 50. These trends are somewhat different than those obtained in previous experimental and analytical studies of low Re number nozzles. It appears that arcjet performance can be enhanced via area ratio optimization.

  1. Arcjet Nozzle Area Ratio Effects

    Science.gov (United States)

    Curran, Francis M.; Sarmiento, Charles J.; Birkner, Bjorn W.; Kwasny, James

    1990-01-01

    An experimental investigation was conducted to determine the effect of nozzle area ratio on the operating characteristics and performance of a low power dc arcjet thruster. Conical thoriated tungsten nozzle inserts were tested in a modular laboratory arcjet thruster run on hydrogen/nitrogen mixtures simulating the decomposition products of hydrazine. The converging and diverging sides of the inserts had half angles of 30 and 20 degrees, respectively, similar to a flight type unit currently under development. The length of the diverging side was varied to change the area ratio. The nozzle inserts were run over a wide range of specific power. Current, voltage, mass flow rate, and thrust were monitored to provide accurate comparisons between tests. While small differences in performance were observed between the two nozzle inserts, it was determined that for each nozzle insert, arcjet performance improved with increasing nozzle area ratio to the highest area ratio tested and that the losses become very pronounced for area ratios below 50. These trends are somewhat different than those obtained in previous experimental and analytical studies of low Re number nozzles. It appears that arcjet performance can be enhanced via area ratio optimization.

  2. Aromatic hydrocarbons at urban, sub-urban, rural (8°52'N; 67°19'W) and remote sites in Venezuela

    Science.gov (United States)

    Holzinger, R.; Kleiss, B.; Donoso, L.; Sanhueza, E.

    Using the novel on-line proton transfer reaction mass spectrometry (PTR-MS) technique, atmospheric concentrations of benzene, toluene, xylenes, and C 9-benzenes were measured in Caracas (urban), Altos de Pipe (sub-urban), Calabozo (rural) and Parupa (remote), during various campaigns in 1999 and 2000. Average daytime mixing ratios measured in Caracas are 1.1, 3.2, 3.7, and 2.7 nmol/mol for benzene, toluene, xylenes, and C 9-benzenes. At the sub-urban site, located only few km from Caracas, relatively low levels (˜20% of the levels measured in Caracas) of these aromatic hydrocarbons were observed. At the rural site during the dry season, higher concentrations of benzene (0.15 nmol/mol) were recorded, whereas those of toluene (0.08 nmol/mol) were lower during that time. The aromatic hydrocarbon ratios in the wet season (benzene: 0.08 nmol/mol; toluene: 0.09 nmol/mol) are consistent with an aged urban plume, whereas biomass burning emissions dominate during the dry season. From rural and urban [benzene]/[toluene] ratios a mean HO concentration of 2.6×10 6 molecules/cm 3 was estimated during the wet season. This value must be considered an overestimate because it does not account for background concentrations which are likely for benzene and toluene. At the remote "La Gran Sabana" region (Parupa) very low mixing ratios (0.031 and 0.015 nmol/mol for benzene and toluene) are showing the pristine region to be unaffected by local sources. From the [benzene]/[toluene] ratio we deduced, that "urban" air arriving from the coastline (350 km) is likely mixed with air containing some background of benzene and toluene. Urban emissions (automobiles) should be the major source of aromatic compounds, however, during the dry season biomass burning seems to make an important contribution.

  3. Air sea ratio reduction initiative

    Energy Technology Data Exchange (ETDEWEB)

    Oberle, Jean

    2010-09-15

    Airfreight is the most expensive mode of transportation as well as the most impacting in terms of CO{sup 2} emissions. It is 7 times more expensive on average to ship by air than shipping by sea 1. Airfreight transportation mode emits 30 times more CO{sup 2} than sea freight mode 2. These elements provided a compelling platform to design a global logistics program to initiate a modal shift from air to sea freight without compromising service to customers.

  4. Vehicle emissions of greenhouse gases and related tracers from a tunnel study: : CO: CO2, N2O: CO2, CH4: CO2, O2: CO2 ratios, and the stable isotopes 13C and 18O in CO2 and CO

    NARCIS (Netherlands)

    Popa, Maria Elena; Vollmer, M. K.; Jordan, A.; Brand, W. A.; Pathirana, S. L.; Rothe, M.; Röckmann, T.

    2014-01-01

    Measurements of CO2, CO, N2O and CH4 mole fractions, O2/N2 ratios and the stable isotopes 13C and 18O in CO2 and CO have been performed in air samples from the Islisberg highway tunnel (Switzerland). The molar CO : CO2 ratios, with an average of (4.15 ± 0.34) ppb:ppm, are lower than reported in

  5. Trace gas emissions from burning Florida wetlands

    Science.gov (United States)

    Cofer, Wesley R.; Levine, Joel S.; Winstead, Edward L.; Lebel, Peter J.; Koller, Albert M.; Hinkle, C. Ross

    1990-02-01

    Measurements of biomass burn-produced trace gases are presented that were obtained using a helicopter at low altitudes above burning Florida wetlands on November 9, 1987, and from both helicopter and light-aircraft samplings on November 7, 1988. Carbon dioxide (CO2) normalized emission ratios (ΔX/ΔCO2; V/V; where X is trace gas) for carbon monoxide (CO), hydrogen (H2), methane (CH4), total nonmethane hydrocarbons (TNMHC), and nitrous oxide (N2O) were obtained over burning graminoid wetlands consisting primarily of Spartina bakeri and Juncus roemerianus. Some interspersed scrub oak (Quercus spp) and saw palmetto (Screnoa repens) were also burned. No significant differences were observed in the emission ratios determined for these gases from samples collected over flaming, mixed, and smoldering phases of combustion during the 1987 fire. Combustion-categorized differences in emission ratios were small for the 1988 fire. Combustion efficiency was relatively good (low emission ratios for reduced gases) for both fires. We believe that the consistently low emission ratios were a unique result of graminoid wetlands fires, in which the grasses and rushes (both small-size fuels) burned rapidly down to standing water and were quickly extinguished. Consequently, the efficiency of the combustion was good and the amount and duration of smoldering combustion was greatly diminished.

  6. Trace gas emissions from burning Florida wetlands

    Science.gov (United States)

    Cofer, Wesley R., III; Levine, Joel S.; Lebel, Peter J.; Winstead, Edward L.; Koller, Albert M., Jr.; Hinkle, C. Ross

    1990-01-01

    Measurements of biomass burn-produced trace gases were obtained using a helicopter at low altitudes above burning Florida wetlands on November 9, 1987, and from both helicopter and light-aircraft samplings on November 7, 1988. Carbon dioxide normalized emission ratios for carbon monoxide, hydrogen, methane, total nonmethane hydrocarbons, and nitrous oxide were obtained over burning graminoid wetlands consisting primarily of Spartina bakeri and Juncus roemerianus. Some interspersed scrub oak and saw palmetto were also burned. No significant differences were observed in the emission ratios determined for these gases from samples collected over flaming, mixed, and smoldering phases of combustion during the 1987 fire. Combustion-categorized differences in emission ratios were small for the 1988 fire. Combustion efficiency was relatively good (low emission ratios for reduced gases) for both fires. It is believed that the consistently low emission ratios were a unique result of graminoid wetlands fires, in which the grasses and rushes burned rapidly down to standing water and were quickly extinguished. Consequently, the efficiency of the combustion was good and the amount and duration of smoldering combustion was greatly deminished.

  7. Incentive Ratios of Fisher Markets

    DEFF Research Database (Denmark)

    Chen, Ning; Deng, Xuaitue; Zhang, Hongyang

    2012-01-01

    In a Fisher market, a market maker sells m items to n potential buyers. The buyers submit their utility functions and money endowments to the market maker, who, upon receiving submitted information, derives market equilibrium prices and allocations of its items. While agents may benefit...... by misreporting their private information, we show that the percentage of improvement by a unilateral strategic play, called incentive ratio, is rather limited—it is less than 2 for linear markets and at most $e^{1/e}\\thickapprox 1.445$ for Cobb-Douglas markets. We further prove that both ratios are tight....

  8. Syncrude emissions reduction project

    Energy Technology Data Exchange (ETDEWEB)

    Fiedler, M.A. [Alstom Power Inc., Knoxville, TN (United States); Ibbotson, P. [Syncrude Canada Ltd., Calgary, AB (Canada)

    2008-07-01

    This paper described an emissions reduction project conducted by Syncrude Canada and various other companies currently developing and processing oil sands in Alberta. Syncrude's upgrader expansion program included the installation of an ammonia-based wet flue gas desulfurizer (FGD) designed to remove sulphur dioxide (SO{sub 2}) from a coker train. Syncrude is also installing the FGD technology at its existing plants. It is expected that installation of the FGDs will reduced total site emissions of SO{sub 2} by 60 per cent. The fluid cokers are used to crack the long hydrocarbon chain bitumen molecules into shorter molecules. It is expected that the FGD system will also reduce particulate and SO{sub 3} levels. The FGD system was selected after an evaluation of technologies used by the coal-fired power industry. A dry FGD system was selected to operate above the water saturation temperature of the flue gas. Calcium oxide was used as a reagent. Hot gas was quenched in a spray dryer absorber with a slurry of calcium hydroxide. Rotary atomizers were used to developer uniform droplets of slurry. The system's fabric filter was a low ratio reverse gas-cleaned unit. Particulate matter from the gases was deposited on the interior of the filter bags. Clean hot gas was drawn through reverse gas fans into a reverse gas manifold. A timeline of the FGD technology installation process was included. 3 tabs., 28 figs.

  9. Ratio Bias and Policy Preferences

    DEFF Research Database (Denmark)

    Pedersen, Rasmus Tue

    2016-01-01

    Numbers permeate modern political communication. While current scholarship on framing effects has focused on the persuasive effects of words and arguments, this article shows that framing of numbers can also substantially affect policy preferences. Such effects are caused by ratio bias, which...

  10. A high signal-to-noise ratio composite quasar spectrum

    International Nuclear Information System (INIS)

    Francis, P.J.; Hewett, P.C.; Foltz, C.B.; Chaffee, F.H.; Weymann, R.J.

    1991-01-01

    A very high signal-to-noise ratio (S/N of about 400) composite spectrum of the rest-frame ultraviolet and optical region of high luminosity quasars is presented. The spectrum is derived from 718 individual spectra obtained as part of the Large Bright Quasar Survey. The moderate resolution, 4A or less, and high signal-to-noise ratio allow numerous weak emission features to be identified. Of particular note is the large equivalent-width of the Fe II emission in the rest-frame ultraviolet and the blue continuum slope of the composite. The primary aim of this paper is to provide a reference spectrum for use in line identifications, and a series of large-scale representations of the composite spectrum are shown. A measure of the standard deviation of the individual quasar spectra from the composite spectrum is also presented. 12 refs

  11. Emission Inventory for Fugitive Emissions in Denmark

    DEFF Research Database (Denmark)

    Plejdrup, Marlene Schmidt; Nielsen, Ole-Kenneth; Nielsen, Malene

    This report presents the methodology and data used in the Danish inventory of fugitive emissions from fuels for the years until 2007. The inventory of fugitive emissions includes CO2, CH4, N2O, NOx, CO, NMVOC, SO2, dioxin, PAH and particulate matter. In 2007 the total Danish emission of greenhouse...

  12. Global Carbon Reservoir Oxidative Ratios

    Science.gov (United States)

    Masiello, C. A.; Gallagher, M. E.; Hockaday, W. C.

    2010-12-01

    Photosynthesis and respiration move carbon and oxygen between the atmosphere and the biosphere at a ratio that is characteristic of the biogeochemical processes involved. This ratio is called the oxidative ratio (OR) of photosynthesis and respiration, and is defined as the ratio of moles of O2 per moles of CO2. This O2/CO2 ratio is a characteristic of biosphere-atmosphere gas fluxes, much like the 13C signature of CO2 transferred between the biosphere and the atmosphere has a characteristic signature. OR values vary on a scale of 0 (CO2) to 2 (CH4), with most ecosystem values clustered between 0.9 and 1.2. Just as 13C can be measured for both carbon fluxes and carbon pools, OR can also be measured for fluxes and pools and can provide information about the processes involved in carbon and oxygen cycling. OR values also provide information about reservoir organic geochemistry because pool OR values are proportional to the oxidation state of carbon (Cox) in the reservoir. OR may prove to be a particularly valuable biogeochemical tracer because of its ability to couple information about ecosystem gas fluxes with ecosystem organic geochemistry. We have developed 3 methods to measure the OR of ecosystem carbon reservoirs and intercalibrated them to assure that they yield accurate, intercomparable data. Using these tools we have built a large enough database of biomass and soil OR values that it is now possible to consider the implications of global patterns in ecosystem OR values. Here we present a map of the natural range in ecosystem OR values and begin to consider its implications. One striking pattern is an apparent offset between soil and biospheric OR values: soil OR values are frequently higher than that of their source biomass. We discuss this trend in the context of soil organic geochemistry and gas fluxes.

  13. Acoustic emission from polycrystalline graphites

    International Nuclear Information System (INIS)

    Ioka, I.; Yoda, S.; Oku, T.; Miyamoto, Y.

    1987-01-01

    Acoustic emission was monitored from polycrystalline graphites with different microstructure (pore size and pore volume) subjected to compressive loading. The graphites used in this study comprised five brands, that is, PGX, ISEM-1, IG-11, IG-15, and ISO-88. A root mean square (RMS) voltage and event counts of acoustic emission for graphites were measured during compressive loading. The acoustic emission was measured using a computed-based data acquisition and analysis system. The graphites were first deformed up to 80 % of the average fracture stress, then unloaded and reloaded again until the fracture occured. During the first loading, the change in RMS voltage for acoustic emission was detected from the initial stage. During the unloading, the RMS voltage became zero level as soon as the applied stress was released and then gradually rose to a peak and declined. The behavior indicated that the reversed plastic deformation occured in graphites. During the second loading, the RMS voltage gently increased until the applied stress exceeded the maximum stress of the first loading; there is no Kaiser effect in the graphites. A bicrystal model could give a reasonable explanation of this results. The empirical equation between the ratio of σ AE to σ f and σ f was obtained. It is considered that the detection of microfracture by the acoustic emission technique is effective in macrofracture prediction of polycrystalline graphites. (author)

  14. Alternative Observers for SI Engine Air/Fuel Ratio Control

    DEFF Research Database (Denmark)

    Hendricks, Elbert; Poulsen, Jannik; Olsen, Mads Bruun

    1996-01-01

    In earlier work it has been shown that a nonlinear observer based on the use of the manifold pressure state equation and a nonlinear fuel film compensator can maintain accurate A/F ratio control during both steady state and transient operation. This observer may be called a manifold absolute pres...... engine control system designer with a variety of robust control systems which can easily be made redundant in order to satisfy newer engine emissions and diagnosis requirements and legislation...

  15. Long-term measurements of biogenic VOCs in an Austrian valley - discussion of seasonal fluctuations of isoprene and monoterpene concentrations

    International Nuclear Information System (INIS)

    Dunkl, J.; Schnitzhofer, R.; Beauchamp, J.; Wisthaler, A; Hansel, A.

    2006-01-01

    Full text: A proton-transfer-reaction mass spectrometer (PTR-MS) was set up at a monitoring station in the river Inn valley (Vomp, Tirol, Austria) for a year-long measurement (February 2004-May 2005) of volatile organic compounds (VOCs) in the local valley air. Measurements of PM 10 , NO x and CO, and certain meteorological parameters were additionally made. Together, these data-sets enabled relationships between VOC abundances, meteorological conditions and anthropogenic emissions (primarily from automobile emissions) to be examined. The work presented here focuses on the biogenic VOCs measured under these real-world outdoor conditions. Initially, data needed to be separated between VOCs of anthropogenic and of biogenic origin. This was achieved by generating a model for the PTR-MS VOC data-set. A clear correlation between benzene and CO concentrations - indicating benzene's predominance from anthropogenic sources - allowed benzene to be used as a tracer for anthropogenic compounds. The model thus allowed a regression to be made whereby the maximum anthropogenic contributions of almost all VOCs could be established relative to benzene. The maximum contribution from biogenic emissions to each VOC could thus be determined as the difference between the total individual VOC signal and the corresponding maximum anthropogenic share. The two biogenic VOCs of principle interest here were isoprene and the monoterpenes (detected by PTR-MS at masses 69 amu and 137 amu, respectively). As expected, abundances of isoprene and the monoterpenes displayed a late-summer maximum (despite good vertical valley air dilution that acts to reduce VOC levels) when temperatures were high and sunlight hours long. Preliminary results will be presented and discussed. (author)

  16. GUT Scale Fermion Mass Ratios

    International Nuclear Information System (INIS)

    Spinrath, Martin

    2014-01-01

    We present a series of recent works related to group theoretical factors from GUT symmetry breaking which lead to predictions for the ratios of quark and lepton Yukawa couplings at the unification scale. New predictions for the GUT scale ratios y μ /y s , y τ /y b and y t /y b in particular are shown and compared to experimental data. For this comparison it is important to include possibly large supersymmetric threshold corrections. Due to this reason the structure of the fermion masses at the GUT scale depends on TeV scale physics and makes GUT scale physics testable at the LHC. We also discuss how this new predictions might lead to predictions for mixing angles by discussing the example of the recently measured last missing leptonic mixing angle θ 13 making this new class of GUT models also testable in neutrino experiments

  17. Ratio Bias and Policy Preferences

    DEFF Research Database (Denmark)

    Pedersen, Rasmus Tue

    2017-01-01

    Numbers permeate modern political communication. While current scholarship on framing effects has focused on the persuasive effects of words and arguments, this article shows that framing of numbers can also substantially affect policy preferences. Such effects are caused by ratio bias, which...... is a general tendency to focus on numerators and pay insufficient attention to denominators in ratios. Using a population-based survey experiment, I demonstrate how differently framed but logically equivalent representations of the exact same numerical value can have large effects on citizens’ preferences...... regarding salient political issues such as education and taxes. Furthermore, the effects of numerical framing are found across most groups of the population, largely regardless of their political predisposition and their general ability to understand and use numerical information. These findings have...

  18. High aspect ratio spheromak experiments

    International Nuclear Information System (INIS)

    Robertson, S.; Schmid, P.

    1987-05-01

    The Reversatron RFP (R/a = 50cm/8cm) has been operated as an ohmically heated spheromak of high aspect ratio. We find that the dynamo can drive the toroidal field upward at rates as high as 10 6 G/sec. Discharges can be initiated and ramped upward from seed fields as low as 50 G. Small toroidal bias fields of either polarity (-0.2 < F < 0.2) do not significantly affect operation. 5 refs., 3 figs

  19. N-15 analysis by emission spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1983-12-31

    The stable isotope of nitrogen, N-15, has become widely used as tracer in agriculture, medicine and biology research. The film gives an overview of the sample preparation and analytical procedures followed in the analysis of the nitrogen isotopic composition (14N/15N ratio) by optical emission spectrometry at the Seibersdorf Laboratory. The subsampling of plant material and the several steps of chemical pretreatment such as Kjeldahl digestion, distillation, titration and adjustment of the proper N concentration in the extract are demonstrated. The preparation of the discharge tubes is shown in detail. Final measurement of the 14N/15N ratio is carried out with the NOI-5 and JASCO emission spectrometers

  20. Envera Variable Compression Ratio Engine

    Energy Technology Data Exchange (ETDEWEB)

    Charles Mendler

    2011-03-15

    Aggressive engine downsizing, variable compression ratio and use of the Atkinson cycle are being combined to improve fuel economy by up to 40 percent relative to port fuel injected gasoline engines, while maintaining full engine power. Approach Engine downsizing is viewed by US and foreign automobile manufacturers as one of the best options for improving fuel economy. While this strategy has already demonstrated a degree of success, downsizing and fuel economy gains are currently limited. With new variable compression ratio technology however, the degree of engine downsizing and fuel economy improvement can be greatly increased. A small variable compression ratio (VCR) engine has the potential to return significantly higher vehicle fuel economy while also providing high power. Affordability and potential for near term commercialization are key attributes of the Envera VCR engine. VCR Technology To meet torque and power requirements, a smaller engine needs to do more work per stroke. This is typically accomplished by boosting the incoming charge with either a turbo or supercharger so that more energy is present in the cylinder per stroke to do the work. With current production engines the degree of engine boosting (which correlates to downsizing) is limited by detonation (combustion knock) at high boost levels. Additionally, the turbo or supercharger needs to be responsive and efficient while providing the needed boost. VCR technology eliminates the limitation of engine knock at high load levels by reducing compression ratio to {approx}9:1 (or whatever level is appropriate) when high boost pressures are needed. By reducing the compression ratio during high load demand periods there is increased volume in the cylinder at top dead center (TDC) which allows more charge (or energy) to be present in the cylinder without increasing the peak pressure. Cylinder pressure is thus kept below the level at which the engine would begin to knock. When loads on the engine are low

  1. A statistical analysis of volatile organic compounds observed during the TEXAQS2000 air quality study at LaPorte, Tx, using proton-transfer-reaction mass spectrometry

    International Nuclear Information System (INIS)

    Kuster, B.; Williams, E.; Fehsenfeld, F.; Jobson, T.; Fall, R.; Lindinger, W.; Karl, T.

    2002-01-01

    Statistical analysis of online VOC measurements obtained by proton-transfer-reaction mass spectrometry (PTR-MS) during the TEXAQS2000 intensive period is presented. The experiment was based at the La Porte site, near the Houston ship channel (HSC), and deployed for continuous long-term monitoring. Multivariate techniques helped to identify various VOC sources in the vicinity of HSC and distinguish between different anthropogenic emissions. An assessment is given of the selectivity and interpretation of mass scans from this online technique in complex urban and industrial VOC matrix. (author)

  2. Intensity ratio among Ne-like FeXVII n=3-2 transitions

    International Nuclear Information System (INIS)

    Morita, Shigeru; Oishi, Tetsutarou; Murakami, Izumi; Goto, Motoshi; Huang, Xianli; Zhang, Hongming

    2016-01-01

    Radial profiles of FeXVII 3s-2p and 3d-2p transitions emitted in wavelength range of 15-17A have been observed in Large Helical Device (LHD). The Chord-integrated radial profiles are converted into radial emissivity profile by means of Abel inversion. The emissivity ratios among FeXVII n=3-2 transitions calculated from the radial emissivity profile are compared with calculation based on a collisional-radiative (CR) model developed for Fe ions. The result reasonably confirms the effect of electron temperature and density on the emissivity ratios. However, the emissivity of 3C (2p"53d "1P_1 → 2p"6) transition is obviously lower than the prediction from the CR model. This discrepancy is consistent with measurements in the solar corona and other laboratory plasmas. (author)

  3. Reproducibility of isotope ratio measurements

    International Nuclear Information System (INIS)

    Elmore, D.

    1981-01-01

    The use of an accelerator as part of a mass spectrometer has improved the sensitivity for measuring low levels of long-lived radionuclides by several orders of magnitude. However, the complexity of a large tandem accelerator and beam transport system has made it difficult to match the precision of low energy mass spectrometry. Although uncertainties for accelerator measured isotope ratios as low as 1% have been obtained under favorable conditions, most errors quoted in the literature for natural samples are in the 5 to 20% range. These errors are dominated by statistics and generally the reproducibility is unknown since the samples are only measured once

  4. GOLD and the fixed ratio

    Directory of Open Access Journals (Sweden)

    Vestbo J

    2012-09-01

    Full Text Available Jørgen VestboUniversity of Manchester, Manchester, UKI read with interest the paper entitled "Diagnosis of airway obstruction in the elderly: contribution of the SARA study" by Sorino et al in a recent issue of this journal.1 Being involved in the Global Initiative for Obstructive Lung Diseases (GOLD, it is nice to see the interest sparked by the GOLD strategy document. However, in the paper by Sorino et al, there are a few misunderstandings around GOLD and the fixed ratio (forced expiratory volume in 1 second/forced volume vital capacity < 0.70 that need clarification.View original paper by Sorino and colleagues.

  5. Methane emissions form terrestrial plants

    Energy Technology Data Exchange (ETDEWEB)

    Bergamaschi, P.; Dentener, F.; Grassi, G.; Leip, A.; Somogyi, Z.; Federici, S.; Seufert, G.; Raes, F. [European Commission, DG Joint Research Centre, Institute for Environment and Sustainability, Ispra (Italy)

    2006-07-01

    In a recent issue of Nature Keppler et al. (2006) report the discovery that terrestrial plants emit CH4 under aerobic conditions. Until now it was thought that bacterial decomposition of plant material under anaerobic conditions, such as in wetlands and water flooded rice paddies, is the main process leading to emissions from terrestrial ecosystems. In a first attempt to upscale these measurements, the authors estimate that global total emissions may be 149 Tg CH4/yr (62-236 Tg CH4/yr), with the main contribution estimated from tropical forests and grasslands (107 Tg CH4/yr with a range of 46-169 Tg CH4/yr). If confirmed, this new source of emission would constitute a significant fraction of the total global methane sources (estimated 500-600 Tg CH4/yr for present day total natural and anthropogenic sources) and have important implications for the global CH4 budget. To accommodate it within the present budget some sources would need to be re-assessed downwards and/or some sinks re-assessed upwards. Furthermore, also considering that methane is a {approx}23 times more powerful greenhouse gas than CO2, the possible feedbacks of these hitherto unknown CH4 emissions on global warming and their impacts on greenhouse gases (GHG) mitigation strategies need to be carefully evaluated. The merit of the paper is without doubt related to the remarkable discovery of a new process of methane emissions active under aerobic conditions. However, we think that the applied approach of scaling up emissions from the leaf level to global totals by using only few measured data (mainly from herbaceous species) and the Net Primary Productivity of the main biomes is scientifically questionable and tends to overestimate considerably the global estimates, especially for forest biomes. Furthermore, some significant constraints on the upper limit of the global natural CH4 emissions arise from the pre-industrial CH4 budget. Pre-industrial atmospheric CH4 mixing ratios have been measured

  6. Plasma emission mechanisms

    International Nuclear Information System (INIS)

    Melrose, D.B.

    1985-01-01

    Only three emission processes are thought to play a role in solar radio emission: plasma emission, gyromagnetic emission and bremsstrahlung. In this chapter plasma emission is discussed and the processes involved in its production are treated, namely, the generation of Langmuir turbulence, the partial conversion into fundamental transverse radiation, production of secondary Langmuir waves and the generation of second-harmonic transverse radiation. (U.K.)

  7. Ion cyclotron emission by spontaneous emission

    Energy Technology Data Exchange (ETDEWEB)

    Da Costa, O [Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking; Gresillon, D [Ecole Polytechnique, 91 - Palaiseau (France). Lab. de Physique des Milieux Ionises

    1994-07-01

    The goal of the study is to examine whether the spontaneous emission can account for ICE (ion cyclotron emission) experimental results, or part of them. A straightforward approach to plasma emission is chosen, investigating the near equilibrium wave radiation by gyrating ions, and thus building from the majority and fast fusion ions the plasma fluctuations and emission on the fast magnetoacoustic or compressional Alfven wave mode in the IC frequency range. Similarities with the ICE experiments are shown: the emission temperature in the presence of fast ions (even in a very small amount), the strong fast ion emission increase with the harmonic, the fine double-line splitting of each peak, the linear but not proportional increase of the peak width with the harmonic. 3 refs., 2 figs.

  8. Ion cyclotron emission by spontaneous emission

    International Nuclear Information System (INIS)

    Da Costa, O.; Gresillon, D.

    1994-01-01

    The goal of the study is to examine whether the spontaneous emission can account for ICE (ion cyclotron emission) experimental results, or part of them. A straightforward approach to plasma emission is chosen, investigating the near equilibrium wave radiation by gyrating ions, and thus building from the majority and fast fusion ions the plasma fluctuations and emission on the fast magnetoacoustic or compressional Alfven wave mode in the IC frequency range. Similarities with the ICE experiments are shown: the emission temperature in the presence of fast ions (even in a very small amount), the strong fast ion emission increase with the harmonic, the fine double-line splitting of each peak, the linear but not proportional increase of the peak width with the harmonic. 3 refs., 2 figs

  9. Biogenic emissions of isoprenoids and NO in China and comparison to anthropogenic emissions

    International Nuclear Information System (INIS)

    Tie Xuexi; Li Guohui; Ying, Zhuming; Guenther, Alex; Madronich, Sasha

    2006-01-01

    northeastern and southern China, there are relatively large biogenic emissions of isoprenoids, leading to an important impact on the ozone production in these regions. Furthermore, the emissions of isoprenoids are highest during summer and noontime, which correlates to the peak of ozone production period. For example, the ratio between summer and winter for the emissions of isoprenoids is about 15 in China. As a result, the biogenic emissions of isoprenoids are significantly larger than the anthropogenic emissions of VOCs in China during daytime in summer. Biogenic NO emissions are mostly produced by agricultural soils which co-exist with large populations and human activity. As a result, the biogenic emissions of NO are mostly overlapped with the anthropogenic emissions of NO, leading to the enhancement in NO concentrations in the high anthropogenic NO emission regions. Finally, the future emissions of isoprene and monoterpenes over China are estimated. The results show that the future biogenic emissions may increase significantly due to land cover changes in central eastern China, which could have a very important impact on ozone formation in this region. However, these estimates are highly uncertain and are presented as a potential scenario to show the importance of possible changes of biogenic emissions in China

  10. Biogenic emissions of isoprenoids and NO in China and comparison to anthropogenic emissions.

    Science.gov (United States)

    Tie, Xuexi; Li, Guohui; Ying, Zhuming; Guenther, Alex; Madronich, Sasha

    2006-12-01

    northeastern and southern China, there are relatively large biogenic emissions of isoprenoids, leading to an important impact on the ozone production in these regions. Furthermore, the emissions of isoprenoids are highest during summer and noontime, which correlates to the peak of ozone production period. For example, the ratio between summer and winter for the emissions of isoprenoids is about 15 in China. As a result, the biogenic emissions of isoprenoids are significantly larger than the anthropogenic emissions of VOCs in China during daytime in summer. Biogenic NO emissions are mostly produced by agricultural soils which co-exist with large populations and human activity. As a result, the biogenic emissions of NO are mostly overlapped with the anthropogenic emissions of NO, leading to the enhancement in NO concentrations in the high anthropogenic NO emission regions. Finally, the future emissions of isoprene and monoterpenes over China are estimated. The results show that the future biogenic emissions may increase significantly due to land cover changes in central eastern China, which could have a very important impact on ozone formation in this region. However, these estimates are highly uncertain and are presented as a potential scenario to show the importance of possible changes of biogenic emissions in China.

  11. Using Ratio Analysis to Evaluate Financial Performance.

    Science.gov (United States)

    Minter, John; And Others

    1982-01-01

    The ways in which ratio analysis can help in long-range planning, budgeting, and asset management to strengthen financial performance and help avoid financial difficulties are explained. Types of ratios considered include balance sheet ratios, net operating ratios, and contribution and demand ratios. (MSE)

  12. Electroplex emission from bi-layer blue emitting organic materials

    Science.gov (United States)

    Zhang, Fujun; Zhao, Suling; Zhao, Dewei; Jiang, Weiwei; Li, Yuan; Yuan, Guangcai; Zhu, Haina; Xu, Zheng

    2007-04-01

    Electroluminescence (EL) and photoluminescence (PL) spectra of an electron donor, an (poly(N-vinylcarbazole) (PVK))/electron acceptor, and a (2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (PBD)) bi-layer solid film are analysed. The EL emission peak has an apparent red-shift with the increase of driving voltage. There maybe exist an electroplex emission between the PVK and PBD interface under high electric field strength. According to their energy level, the electroplex emission peak should locate at 460 nm. There are great spectra overlapping between PVK emission and electroplex emission, and the ratio of electroplex emission intensity to exciton emission intensity (Ielectroplex/Iexciton) increases from 0.38 at 10 to 0.81 at 16 V. Therefore the measured emission peaks continuously shift from 410 nm at 10 V to 445 nm at 16 V.

  13. Electroplex emission from bi-layer blue emitting organic materials

    International Nuclear Information System (INIS)

    Zhang Fujun; Zhao Suling; Zhao Dewei; Jiang Weiwei; Li Yuan; Yuan Guangcai; Zhu Haina; Xu Zheng

    2007-01-01

    Electroluminescence (EL) and photoluminescence (PL) spectra of an electron donor, an (poly(N-vinylcarbazole) (PVK))/electron acceptor, and a (2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (PBD)) bi-layer solid film are analysed. The EL emission peak has an apparent red-shift with the increase of driving voltage. There maybe exist an electroplex emission between the PVK and PBD interface under high electric field strength. According to their energy level, the electroplex emission peak should locate at 460 nm. There are great spectra overlapping between PVK emission and electroplex emission, and the ratio of electroplex emission intensity to exciton emission intensity (I electroplex /I exciton ) increases from 0.38 at 10 to 0.81 at 16 V. Therefore the measured emission peaks continuously shift from 410 nm at 10 V to 445 nm at 16 V

  14. Electroplex emission from bi-layer blue emitting organic materials

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Fujun; Zhao Suling; Zhao Dewei; Jiang Weiwei; Li Yuan; Yuan Guangcai; Zhu Haina; Xu Zheng [Key Laboratory for Information Storage, Display and Materials, Institute of Optoelectronic Technology, Beijing Jiaotong University, Beijing 100044 (China)

    2007-04-15

    Electroluminescence (EL) and photoluminescence (PL) spectra of an electron donor, an (poly(N-vinylcarbazole) (PVK))/electron acceptor, and a (2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (PBD)) bi-layer solid film are analysed. The EL emission peak has an apparent red-shift with the increase of driving voltage. There maybe exist an electroplex emission between the PVK and PBD interface under high electric field strength. According to their energy level, the electroplex emission peak should locate at 460 nm. There are great spectra overlapping between PVK emission and electroplex emission, and the ratio of electroplex emission intensity to exciton emission intensity (I{sub electroplex}/I{sub exciton}) increases from 0.38 at 10 to 0.81 at 16 V. Therefore the measured emission peaks continuously shift from 410 nm at 10 V to 445 nm at 16 V.

  15. BENEFITS AND CHALLENGES OF VARIABLE COMPRESSION RATIO AT DIESEL ENGINES

    Directory of Open Access Journals (Sweden)

    Radivoje B Pešić

    2010-01-01

    Full Text Available The compression ratio strongly affects the working process and provides an exceptional degree of control over engine performance. In conventional internal combustion engines, the compression ratio is fixed and their performance is therefore a compromise between conflicting requirements. One fundamental problem is that drive units in the vehicles must successfully operate at variable speeds and loads and in different ambient conditions. If a diesel engine has a fixed compression ratio, a minimal value must be chosen that can achieve a reliable self-ignition when starting the engine in cold start conditions. In diesel engines, variable compression ratio provides control of peak cylinder pressure, improves cold start ability and low load operation, enabling the multi-fuel capability, increase of fuel economy and reduction of emissions. This paper contains both theoretical and experimental investigation of the impact that automatic variable compression ratios has on working process parameters in experimental diesel engine. Alternative methods of implementing variable compression ratio are illustrated and critically examined.

  16. Emissions from forest fires near Mexico City

    Directory of Open Access Journals (Sweden)

    R. J. Yokelson

    2007-11-01

    Full Text Available The emissions of NOx (defined as NO (nitric oxide + NO2 (nitrogen dioxide and hydrogen cyanide (HCN, per unit amount of fuel burned, from fires in the pine forests that dominate the mountains surrounding Mexico City (MC are about 2 times higher than normally observed for forest burning. The ammonia (NH3 emissions are about average for forest burning. The upper limit for the mass ratio of NOx to volatile organic compounds (VOC for these MC-area mountain fires was ~0.38, which is similar to the NOx/VOC ratio in the MC urban area emissions inventory of 0.34, but much larger than the NOx/VOC ratio for tropical forest fires in Brazil (~0.068. The nitrogen enrichment in the fire emissions may be due to deposition of nitrogen-containing pollutants in the outflow from the MC urban area. This effect may occur worldwide wherever biomass burning coexists with large urban areas (e.g. the tropics, southeastern US, Los Angeles Basin. The molar emission ratio of HCN to carbon monoxide (CO for the mountain fires was 0.012±0.007, which is 2–9 times higher than widely used literature values for biomass burning. The ambient molar ratio HCN/CO in the MC-area outflow is about 0.003±0.0003. Thus, if only mountain fires emit significant amounts of HCN, these fires may be contributing about 25% of the CO production in the MC-area (~98–100 W and 19–20 N. Comparing the PM10/CO and PM2.5/CO mass ratios in the MC Metropolitan Area emission inventory (0.0115 and 0.0037 to the PM1/CO mass ratio for the mountain fires (0.133 then suggests that these fires could produce as much as ~79–92% of the primary fine particle mass generated in the MC-area. Considering both the uncertainty in the HCN/CO ratios and secondary aerosol formation in the urban and fire emissions implies that about 50±30% of the "aged" fine particle mass in the March 2006 MC-area outflow could be from these fires.

  17. QSOs with narrow emission lines

    International Nuclear Information System (INIS)

    Baldwin, J.A.; Mcmahon, R.; Hazard, C.; Williams, R.E.

    1988-01-01

    Observations of two new high-redshift, narrow-lined QSOs (NLQSOs) are presented and discussed together with observations of similar objects reported in the literature. Gravitational lensing is ruled out as a possible means of amplifying the luminosity for one of these objects. It is found that the NLQSOs have broad bases on their emission lines as well as the prominent narrow cores which define this class. Thus, these are not pole-on QSOs. The FWHM of the emission lines fits onto the smoothly falling tail of the lower end of the line-width distribution for complete QSO samples. The equivalent widths of the combined broad and narrow components of the lines are normal for QSOs of the luminosity range under study. However, the NLQSOs do show ionization differences from broader-lined QSOs; most significant, the semiforbidden C III/C IV intensity ratio is unusually low. The N/C abundance ratio in these objects is found to be normal; the Al/C abundance ratio may be quite high. 38 references

  18. Direct ecosystem fluxes of volatile organic compounds from oil palms in South-East Asia

    Directory of Open Access Journals (Sweden)

    P. K. Misztal

    2011-09-01

    Full Text Available This paper reports the first direct eddy covariance fluxes of reactive biogenic volatile organic compounds (BVOCs from oil palms to the atmosphere using proton-transfer-reaction mass spectrometry (PTR-MS, measured at a plantation in Malaysian Borneo. At midday, net isoprene flux constituted the largest fraction (84 % of all emitted BVOCs measured, at up to 30 mg m−2 h−1 over 12 days. By contrast, the sum of its oxidation products methyl vinyl ketone (MVK and methacrolein (MACR exhibited clear deposition of 1 mg m−2 h−1, with a small average canopy resistance of 230 s m−1. Approximately 15 % of the resolved BVOC flux from oil palm trees could be attributed to floral emissions, which are thought to be the largest reported biogenic source of estragole and possibly also toluene. Although on average the midday volume mixing ratio of estragole exceeded that of toluene by almost a factor of two, the corresponding fluxes of these two compounds were nearly the same, amounting to 0.81 and 0.76 mg m−2 h−1, respectively. By fitting the canopy temperature and PAR response of the MEGAN emissions algorithm for isoprene and other emitted BVOCs a basal emission rate of isoprene of 7.8 mg m−2 h−1 was derived. We parameterise fluxes of depositing compounds using a resistance approach using direct canopy measurements of deposition. Consistent with Karl et al. (2010, we also propose that it is important to include deposition in flux models, especially for secondary oxidation products, in order to improve flux predictions.

  19. Analysis of local-scale background concentrations of methane and other gas-phase species in the Marcellus Shale

    Directory of Open Access Journals (Sweden)

    J. Douglas Goetz

    2017-02-01

    Full Text Available The Marcellus Shale is a rapidly developing unconventional natural gas resource found in part of the Appalachian region. Air quality and climate concerns have been raised regarding development of unconventional natural gas resources. Two ground-based mobile measurement campaigns were conducted to assess the impact of Marcellus Shale natural gas development on local scale atmospheric background concentrations of air pollution and climate relevant pollutants in Pennsylvania. The first campaign took place in Northeastern and Southwestern PA in the summer of 2012. Compounds monitored included methane (CH4, ethane, carbon monoxide (CO, nitrogen dioxide, and Proton Transfer Reaction Mass Spectrometer (PTR-MS measured volatile organic compounds (VOC including oxygenated and aromatic VOC. The second campaign took place in Northeastern PA in the summer of 2015. The mobile monitoring data were analyzed using interval percentile smoothing to remove bias from local unmixed emissions to isolate local-scale background concentrations. Comparisons were made to other ambient monitoring in the Marcellus region including a NOAA SENEX flight in 2013. Local background CH4 mole fractions were 140 ppbv greater in Southwestern PA compared to Northeastern PA in 2012 and background CH4 increased 100 ppbv from 2012 to 2015. CH4 local background mole fractions were not found to have a detectable relationship between well density or production rates in either region. In Northeastern PA, CO was observed to decrease 75 ppbv over the three year period. Toluene to benzene ratios in both study regions were found to be most similar to aged rural air masses indicating that the emission of aromatic VOC from Marcellus Shale activity may not be significantly impacting local background concentrations. In addition to understanding local background concentrations the ground-based mobile measurements were useful for investigating the composition of natural gas emissions in the region.

  20. Vehicle Emissions Risk Management

    International Nuclear Information System (INIS)

    Ibrahem, L.G.

    2004-01-01

    Vehicle emissions are considered as a main source for air pollution. Emissions regulation is now well developed in most countries to meet cleaner air quality. Reducing emissions by using cleaner fuels, which meet certain specification, is not enough to get cleaner air, yet the vehicle technology is not improved. Here we will outline the following: - development in fuel specification and emissions regulation. main facts linking vehicle emissions, fuel properties and air quality. catalytic converter technology. Emissions sources: In modem cities, vehicle traffic is potentially a major source of emissions. However sometimes other sources of emissions from industry and other stationary sources can be equally important and include emissions that are of greater toxicity than those from vehicles

  1. Quantitative structure activity relationships (QSAR) for binary mixtures at non-equitoxic ratios based on toxic ratios-effects curves.

    Science.gov (United States)

    Tian, Dayong; Lin, Zhifen; Yin, Daqiang

    2013-01-01

    The present study proposed a QSAR model to predict joint effects at non-equitoxic ratios for binary mixtures containing reactive toxicants, cyanogenic compounds and aldehydes. Toxicity of single and binary mixtures was measured by quantifying the decrease in light emission from the Photobacterium phosphoreum for 15 min. The joint effects of binary mixtures (TU sum) can thus be obtained. The results showed that the relationships between toxic ratios of the individual chemicals and their joint effects can be described by normal distribution function. Based on normal distribution equations, the joint effects of binary mixtures at non-equitoxic ratios ( [Formula: see text]) can be predicted quantitatively using the joint effects at equitoxic ratios ( [Formula: see text]). Combined with a QSAR model of [Formula: see text]in our previous work, a novel QSAR model can be proposed to predict the joint effects of mixtures at non-equitoxic ratios ( [Formula: see text]). The proposed model has been validated using additional mixtures other than the one used for the development of the model. Predicted and observed results were similar (p>0.05). This study provides an approach to the prediction of joint effects for binary mixtures at non-equitoxic ratios.

  2. Ammonia emissions in Europe

    DEFF Research Database (Denmark)

    Jacobsen, Brian H.

    2012-01-01

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

  3. Effect of host polymer blends to phosphorescence emission | Alias ...

    African Journals Online (AJOL)

    Each polymer was blended with the same ratio composition. The influences of host polymer composition to the phosphorescence emission were observed under pulsed UV excitation source of Xenon lamp. The results shows that there were changing in the phosphorescence emission and life time with difference host ...

  4. Carbon emission from farm operations.

    Science.gov (United States)

    Lal, R

    2004-09-01

    This manuscript is a synthesis of the available information on energy use in farm operations, and its conversion into carbon equivalent (CE). A principal advantage of expressing energy use in terms of carbon (C) emission as kg CE lies in its direct relation to the rate of enrichment of atmospheric concentration of CO2. Synthesis of the data shows that estimates of emissions in kg CE/ha are 2-20 for different tillage operations, 1-1.4 for spraying chemicals, 2-4 for drilling or seeding and 6-12 for combine harvesting. Similarly, estimates of C emissions in kg CE/kg for different fertilizer nutrients are 0.9-1.8 for N, 0.1-0.3 for P2O5, 0.1-0.2 for K20 and 0.03-0.23 for lime. Estimates of C emission in kg CE/kg of active ingredient (a.i.) of different pesticides are 6.3 for herbicides, 5.1 for insecticides and 3.9 for fungicides. Irrigation, lifting water from deep wells and using sprinkling systems, emits 129+/-98 kg CE for applying 25 cm of water and 258+/-195 for 50 cm of water. Emission for different tillage methods are 35.3 kg CE/ha for conventional till, 7.9 kg CE/ha for chisel till or minimum till, and 5.8 kg CE/ha for no-till method of seedbed preparation. In view of the high C costs of major inputs, sustainable management of agricultural ecosystems implies that an output/input ratio, expressed either as gross or net output of C, must be >1 and has an increasing trend over time.

  5. Emissions Modeling Clearinghouse

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Emissions Modeling Clearinghouse (EMCH) supports and promotes emissions modeling activities both internal and external to the EPA. Through this site, the EPA...

  6. National Emission Inventory

    Data.gov (United States)

    U.S. Environmental Protection Agency — The National Emission Inventory contains measured, modeled, and estimated data for emissions of all known source categories in the US (stationary sources, fires,...

  7. Emissions Trading Resources

    Science.gov (United States)

    Learn about emissions trading programs, also known as cap and trade programs, which are market-based policy tools for protecting human health and the environment by controlling emissions from a group of sources.

  8. What Is Emissions Trading?

    Science.gov (United States)

    Learn the basics about how emissions trading uses a market-based policy tool used to control large amounts of pollution emissions from a group of sources in order to protect human health and the environment.

  9. World Emission RETRO ANTHRO

    Data.gov (United States)

    Washington University St Louis — Anthropogenic and vegetation fire emissions data were generated monthly covering a period of 1960 to 2000. Anthropogenic emissions in the RETRO inventory are derived...

  10. Emissions & Measurements - Black Carbon

    Science.gov (United States)

    Emissions and Measurement (EM) research activities performed within the National Risk Management Research Lab NRMRL) of EPA's Office of Research and Development (ORD) support measurement and laboratory analysis approaches to accurately characterize source emissions, and near sour...

  11. Biodiesel Emissions Analysis Program

    Science.gov (United States)

    Using existing data, the EPA's biodiesel emissions analysis program sought to quantify the air pollution emission effects of biodiesel for diesel engines that have not been specifically modified to operate on biodiesel.

  12. Dioxin emissions and sources

    International Nuclear Information System (INIS)

    1994-01-01

    The papers presented at the seminar discussed dioxin emissions and sources, dioxin pollution of soils, waste water and sewage sludge, stocktaking of emission sources, and exposure and risk analyses for dioxin and other pollutants. (EF) [de

  13. National Emission Information System

    International Nuclear Information System (INIS)

    Sajtakova, E.; Spisakova, K.

    2005-01-01

    In this presentation the Slovak National Emission Information System (NEIS) is presented. The NEIS represents hierarchical oriented modular system of acquisition, verification, saving and reporting of data about annual emissions and payments for pollution of atmosphere

  14. Economic growth and carbon emission control

    Science.gov (United States)

    Zhang, Zhenyu

    The question about whether environmental improvement is compatible with continued economic growth remains unclear and requires further study in a specific context. This study intends to provide insight on the potential for carbon emissions control in the absence of international agreement, and connect the empirical analysis with theoretical framework. The Chinese electricity generation sector is used as a case study to demonstrate the problem. Both social planner and private problems are examined to derive the conditions that define the optimal level of production and pollution. The private problem will be demonstrated under the emission regulation using an emission tax, an input tax and an abatement subsidy respectively. The social optimal emission flow is imposed into the private problem. To provide tractable analytical results, a Cobb-Douglas type production function is used to describe the joint production process of the desired output and undesired output (i.e., electricity and emissions). A modified Hamiltonian approach is employed to solve the system and the steady state solutions are examined for policy implications. The theoretical analysis suggests that the ratio of emissions to desired output (refer to 'emission factor'), is a function of productive capital and other parameters. The finding of non-constant emission factor shows that reducing emissions without further cutting back the production of desired outputs is feasible under some circumstances. Rather than an ad hoc specification, the optimal conditions derived from our theoretical framework are used to examine the relationship between desired output and emission level. Data comes from the China Statistical Yearbook and China Electric Power Yearbook and provincial information of electricity generation for the year of 1993-2003 are used to estimate the Cobb-Douglas type joint production by the full information maximum likelihood (FIML) method. The empirical analysis shed light on the optimal

  15. Blue Emission in Proteins

    OpenAIRE

    Sarkar, Sohini; Sengupta, Abhigyan; Hazra, Partha; Mandal, Pankaj

    2014-01-01

    Recent literatures reported blue-green emission from amyloid fibril as exclusive signature of fibril formation. This unusual visible luminescence is regularly used to monitor fibril growth. Blue-green emission has also been observed in crystalline protein and in solution. However, the origin of this emission is not known exactly. Our spectroscopic study of serum proteins reveals that the blue-green emission is a property of protein monomer. Evidences suggest that semiconductor-like band struc...

  16. Isokinetic Hamstrings: Quadriceps Ratios in Intercollegiate Athletes.

    Science.gov (United States)

    Rosene, John M.; Fogarty, Tracey D.; Mahaffey, Brian L.

    2001-01-01

    Compared the differences in the concentric hamstrings to quadriceps (H:Q) ratio among athletes in different sports at three velocities. Measurement of H:Q ratio of both knees among male and female college athletes indicated that the H:Q ratio increased as velocity increased. No differences existed for the H:Q ratio for sport or side of body. (SM)

  17. Nitrous oxide emission by aquatic macrofauna

    Science.gov (United States)

    Stief, Peter; Poulsen, Morten; Nielsen, Lars Peter; Brix, Hans; Schramm, Andreas

    2009-01-01

    A large variety of aquatic animals was found to emit the potent greenhouse gas nitrous oxide when nitrate was present in the environment. The emission was ascribed to denitrification by ingested bacteria in the anoxic animal gut, and the exceptionally high N2O-to-N2 production ratio suggested delayed induction of the last step of denitrification. Filter- and deposit-feeding animal species showed the highest rates of nitrous oxide emission and predators the lowest, probably reflecting the different amounts of denitrifying bacteria in the diet. We estimate that nitrous oxide emission by aquatic animals is quantitatively important in nitrate-rich aquatic environments like freshwater, coastal marine, and deep-sea ecosystems. The contribution of this source to overall nitrous oxide emission from aquatic environments might further increase because of the projected increase of nitrate availability in tropical regions and the numeric dominance of filter- and deposit-feeders in eutrophic ecosystems. PMID:19255427

  18. Correction of UBV Photometry for Emission Lines

    Directory of Open Access Journals (Sweden)

    Skopal A.

    2003-12-01

    Full Text Available We investigate the effect on U,B,V magnitudes of the removal of emission lines from the spectra of some symbiotic stars and novae during their nebular phases. We approach this problem by the precise reconstruction of the composite UV/optical continuum and the line spectrum. The corrections ΔU, ΔB and ΔV are determined from the ratio of fluxes with and without emission lines. We demonstrate the effect for symbiotic nova V1016 Cyg during its nebular phase. We find that about 68%, 78% and 66% of the observed flux in the U, B and V filters is radiated in the emission lines. The effect should be taken into account before using the observed color indices of emission-line objects for diagnosis of their radiation in the continuum.

  19. Nitrous oxide emission by aquatic macrofauna

    DEFF Research Database (Denmark)

    Stief, Peter; Poulsen, Morten; Nielsen, Lars Peter

    2009-01-01

      A large variety of aquatic animals was found to emit the potent greenhouse gas nitrous oxide when nitrate was present in the environment. The emission was ascribed to denitrification by ingested bacteria in the anoxic animal gut, and the exceptionally high N2O-to-N2 production ratio suggested...... delayed induction of the last step of denitrification. Filter- and deposit-feeding animal species showed the highest rates of nitrous oxide emission and predators the lowest, probably reflecting the different amounts of denitrifying bacteria in the diet. We estimate that nitrous oxide emission by aquatic...... animals is quantitatively important in nitraterich aquatic environments like freshwater, coastal marine, and deep-sea ecosystems. The contribution of this source to overall nitrous oxide emission from aquatic environments might further increase because of the projected increase of nitrate availability...

  20. Emission computed tomography

    International Nuclear Information System (INIS)

    Ott, R.J.

    1986-01-01

    Emission Computed Tomography is a technique used for producing single or multiple cross-sectional images of the distribution of radionuclide labelled agents in vivo. The techniques of Single Photon Emission Computed Tomography (SPECT) and Positron Emission Tomography (PET) are described with particular regard to the function of the detectors used to produce images and the computer techniques used to build up images. (UK)

  1. Changes in Atmospheric Butanes and Pentanes and Their Isomeric Ratios in the Continental United States

    Science.gov (United States)

    Rossabi, Sam; Helmig, Detlev

    2018-04-01

    Nonmethane hydrocarbons have been used as tracers in research on emissions and atmospheric oxidation chemistry. This research investigates source region mixing ratio trends of the nonmethane hydrocarbons i-butane, n-butane, i-pentane, and n-pentane, and the (i/n) isomeric ratios of these compounds between 2001 and 2015. Data collected at Photochemical Assessment Monitoring Stations, mandated by the U.S. Environmental Protection Agency in ozone nonattainment areas, and data collected at Global Greenhouse Gas Reference Network sites within the National Oceanic and Atmospheric Administration network, and analyzed at the Institute of Arctic and Alpine Research at the University of Colorado-Boulder, were examined. Among all considered species, linear regression analyses on concentration time series had negative slopes at 81% of sites, indicating predominantly declining butane and pentane atmospheric concentrations. Mostly negative slopes (78% of sites) were found for the (i/n) butane and pentane isomeric ratios, including all six and seven statistically significant (i/n) butane and pentane trends, respectively. Over the 15 year investigation period and averaged over all sites, total relative changes were 30 and 45% for the (i/n) ratios of butanes and pentanes, respectively, with a relative increase in the prominence of the n-isomers. Most likely causes include changing isomeric ratios in gasoline sector emissions, and increasing influence of oil and natural gas industry emissions. Changes in concentrations and isomeric ratios depend on proximity of contributing emission sources to measurement sites.

  2. Electroplex emission of the blend film of PVK and DPVBi

    Science.gov (United States)

    Li, Junming; Xu, Zheng; Zhang, Fujun; Zhao, Suling; Song, Dandan; Zhu, Haina; Song, Jinglu; Wang, Yongsheng; Xu, Xurong

    2010-04-01

    Influences of electric fields on the emission from organic light-emitting diodes (OLEDs) based on poly(N-vinylcarbazole) (PVK) and 4‧-bis(2-2diphenylvinyl)-1,1‧-biphenyl (DPVBi) as the active emission layer are studied. Electroluminescence (EL) spectra of PVK:DPVBi (1:1 w/w) films show one new emission peak locating at 640 nm compared with its photoluminescence (PL) spectra. There may be exists an electroplex emission between the PVK and DPVBi under high electric field strength. The emission intensity of peaking at 640 nm strongly depends on the driving voltage, and the ratio of electroplex emission intensity to exciton emission intensity (Ielectroplex/Iexciton) increases with the increase of driving voltage.

  3. International emissions trading

    DEFF Research Database (Denmark)

    Boom, Jan Tjeerd

    This thesis discusses the design and political acceptability of international emissions trading. It is shown that there are several designs options for emissions trading at the national level that have a different impact on output and thereby related factors such as employment and consumer prices....... The differences in impact of the design make that governments may prefer different designs of emissions trading in different situations. The thesis furthermore establishes that international emissions trading may lead to higher overall emissions, which may make it a less attractive instrument....

  4. Shipping emissions in ports

    OpenAIRE

    Merk, Olaf

    2014-01-01

    Shipping emissions in ports are substantial, accounting for 18 million tonnes of CO2 emissions, 0.4 million tonnes of NOx, 0.2 million of SOx and 0.03 million tonnes of PM10 in 2011. Around 85% of emissions come from containerships and tankers. Containerships have short port stays, but high emissions during these stays. Most of CO2 emissions in ports from shipping are in Asia and Europe (58%), but this share is low compared to their share of port calls (70%). European ports have much less emi...

  5. Eddy covariance flux measurements of biogenic VOCs during ECHO 2003 using proton transfer reaction mass spectrometry

    Directory of Open Access Journals (Sweden)

    C. Spirig

    2005-01-01

    Full Text Available Within the framework of the AFO 2000 project ECHO, two PTR-MS instruments were operated in combination with sonic anemometers to determine biogenic VOC fluxes from a mixed deciduous forest site in North-Western Germany. The measurement site was characterised by a forest of inhomogeneous composition, complex canopy structure, limited extension in certain wind directions and frequent calm wind conditions during night time. The eddy covariance (EC technique was applied since it represents the most direct flux measurement approach on the canopy scale and is, therefore, least susceptible to these non-ideal conditions. A specific flux calculation method was used to account for the sequential multi-component PTR-MS measurements and allowing an individual delay time adjustment as well as a rigorous quality control based on cospectral analysis. The validated flux results are consistent with light and temperature dependent emissions of isoprene and monoterpenes from this forest, with average daytime emissions of 0.94 and 0.3µg m-2s-1, respectively. Emissions of methanol reached on average 0.087µg m-2s-1 during daytime, but fluxes were too small to be detected during night time. Upward fluxes of the isoprene oxidation products methyl vinyl ketone (MVK and methacrolein (MACR were also found, being two orders of magnitude lower than those of isoprene. Calculations with an analytical footprint model indicate that the observed isoprene fluxes correlate with the fraction of oaks within the footprints of the flux measurement.

  6. Development of air fuel ratio sensor; A/F sensor no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Sakawa, T; Hori, M [Denso Corp., Aichi (Japan); Nakamura, Y [Toyota Motor Corp., Aichi (Japan)

    1997-10-01

    The Air Fuel Ratio Sensor (A/F sensor), which is applied to a 1997 model year Low Emission Vehicle (LEV) was developed. This sensor enables the detection of the exhaust gas air fuel ratio, both lean and rich of stoichiometric. It has an effective air fuel ratio range from 12 to 18 as required for LEV regulation. It has the fast light off, - within 20 seconds - to minimize exhaust hydrocarbon content. Further, it has fast response time, less than 200 msec, to improve the air fuel ratio controllability. 3 refs., 7 figs.

  7. Air Emissions Factors and Quantification

    Science.gov (United States)

    Emissions factors are used in developing air emissions inventories for air quality management decisions and in developing emissions control strategies. This area provides technical information on and support for the use of emissions factors.

  8. Effects of stabilizer ratio on photoluminescence properties of sol-gel ZnO nano-structured thin films

    International Nuclear Information System (INIS)

    Boudjouan, F.; Chelouche, A.; Touam, T.; Djouadi, D.; Khodja, S.; Tazerout, M.; Ouerdane, Y.; Hadjoub, Z.

    2015-01-01

    Nanostructured ZnO thin films with different molar ratios of MEA to zinc acetate (0.5, 1.0, 1.5 and 2.0) have been deposited on glass substrates by a sol–gel dip coating technique. X-ray diffraction, Scanning Electron Microscopy, UV–visible spectrophotometry and photoluminescence spectroscopy have been employed to investigate the effect of MEA stabilizer ratio on structural, morphological, absorbance and emission properties of the ZnO thin films. Diffraction patterns have shown that all the films are polycrystalline and exhibit a wurtzite hexagonal structure. The c axis orientation has been enhanced with increasing stabilizer ratio. SEM micrographs have revealed that the morphology of the ZnO films depend on stabilizer ratio. The UV–visible absorption spectra have demonstrated that the optical absorption is affected by stabilizer ratio. The photoluminescence spectra have indicated one ultraviolet and two visible emission bands (green and red), while band intensities are found to be dependent on stabilizer ratio. ZnO thin films deposited at MEA ratio of 1.0 show the highest UV emission while the minimum UV emission intensity is observed in thin films deposited at ratio of 0.5 and the maximum green has been recorded for films deposited at MEA ratio of 2.0. - Highlight: • c axis orientation increases with increasing MEA ratio. • The increase of MEA ration from 0.5 to 1.0 enhances greatly the UV emission. • The larger I UV /I visible is obtained for the MEA to Zn ratio of 1:1. • The MEA ratio of 0.5 favors the formation of large density of V zn . • The MEA ratio of 2.0 increases the V o density

  9. Aroma analysis and quality control of food using highly sensitive analytical methods

    International Nuclear Information System (INIS)

    Mayr, D.

    2003-02-01

    This thesis deals with the development of quality control methods for food based on headspace measurements by Proton-Transfer-Reaction Mass-Spectrometry (PTR-MS) and with aroma analysis of food using PTR-MS and Gas Chromatography-Olfactometry (GC-O). An objective method was developed for the determination of a herb extract's quality; this quality was checked by a sensory analysis until now. The concentrations of the volatile organic compounds (VOCs) in the headspace of 81 different batches were measured by PTR-MS. Based on the sensory judgment of the customer, characteristic differences in the emissions of 'good' and 'bad' quality samples were identified and a method for the quality control of this herb extract was developed. This novel method enables the producing company to check and ensure that they are only selling high-quality products and therefore avoid complaints of the customer. Furthermore this method can be used for controlling, optimizing and automating the production process. VOCs emitted by meat were investigated using PTR-MS to develop a rapid, non-destructive and quantitative technique for determination of the microbial contamination of meat. Meat samples (beef, pork and poultry) that were wrapped into different kinds of packages (air and vacuum) were stored in at 4 o C for up to 13 days. The emitted VOCs were measured as a function of storage time and identified partly. The concentration of many of the measured VOCs, e.g. sulfur compounds like methanethiol, dimethylsulfide and dimethyldisulfide, largely increased over the storage time. There were big differences in the emissions of normal air- and vacuum-packed meat. VOCs typically emitted by air-packaged meat were methanethiol, dimethylsulfide and dimethyldisulfide, while ethanol and methanol were found in vacuum-packaged meat. A comparison of the PTR-MS results with those obtained by a bacteriological examination performed at the same time showed strong correlations (up to 99 %) between the

  10. Chemiluminescence-based multivariate sensing of local equivalence ratios in premixed atmospheric methane-air flames

    Energy Technology Data Exchange (ETDEWEB)

    Tripathi, Markandey M.; Krishnan, Sundar R.; Srinivasan, Kalyan K.; Yueh, Fang-Yu; Singh, Jagdish P.

    2011-09-07

    Chemiluminescence emissions from OH*, CH*, C2, and CO2 formed within the reaction zone of premixed flames depend upon the fuel-air equivalence ratio in the burning mixture. In the present paper, a new partial least square regression (PLS-R) based multivariate sensing methodology is investigated and compared with an OH*/CH* intensity ratio-based calibration model for sensing equivalence ratio in atmospheric methane-air premixed flames. Five replications of spectral data at nine different equivalence ratios ranging from 0.73 to 1.48 were used in the calibration of both models. During model development, the PLS-R model was initially validated with the calibration data set using the leave-one-out cross validation technique. Since the PLS-R model used the entire raw spectral intensities, it did not need the nonlinear background subtraction of CO2 emission that is required for typical OH*/CH* intensity ratio calibrations. An unbiased spectral data set (not used in the PLS-R model development), for 28 different equivalence ratio conditions ranging from 0.71 to 1.67, was used to predict equivalence ratios using the PLS-R and the intensity ratio calibration models. It was found that the equivalence ratios predicted with the PLS-R based multivariate calibration model matched the experimentally measured equivalence ratios within 7%; whereas, the OH*/CH* intensity ratio calibration grossly underpredicted equivalence ratios in comparison to measured equivalence ratios, especially under rich conditions ( > 1.2). The practical implications of the chemiluminescence-based multivariate equivalence ratio sensing methodology are also discussed.

  11. Study of nuclear heat application systems for arresting CO2 emission

    International Nuclear Information System (INIS)

    Fumizawa, Motoo; Inaba, Yoshitomo; Hishida, Makoto; Ogata, Kan; Yamada, Seiya.

    1996-11-01

    The objective of the paper is to investigate the systems for arresting CO 2 emission and for the effective utilization of fossil fuel. We studied the fossil fuel reforming systems to decrease the CO 2 emission rate per unit amount of heat generation by fossil fuel. Feed materials for reforming system were natural gas, crude oil, oil sand, oil shale and coal. Products by reforming were hydrogen, methane, methanol and gasoline. We examined CO 2 emission ratio of ten systems with different feed material and product. The CO 2 emission ratio was the ratio of CO 2 emission rate per unit amount of heat generation between the products and the feed materials, and was the important index. As the results, the CO 2 emission ratio for the coal to methane reforming system using steam gasifier had the lowest value of 51%. It means that the CO 2 emission rate of the product from the coal to methane reforming system was 51% of the emission rate of the feed material, that is, the system is very effective to arrest the CO 2 emission. The CO 2 emission ratio increases in the following order: the reforming systems from coal to methanol, heavy oil to hydrogen and natural gas to hydrogen. It was clarified that the system of coal to methane reforming was very effective for arresting CO 2 emission compared to the other systems, moreover the nuclear heat using rate and thermal efficiency of the plant of the system were the highest. (author)

  12. Development and improvement of historical emission inventory in Asia

    Science.gov (United States)

    Kurokawa, J. I.; Yumimoto, K.; Itahashi, S.; Maki, T.; Nagashima, T.; Ohara, T.

    2016-12-01

    Due to the rapid growth of economy and population, Asia becomes the largest emitter regions of air pollutants and greenhouse gases in the world. To tackle this problem, it is essential to understand the current status and past trend and to estimate effectiveness of mitigation measures using monitoring data, air quality and climate models, and emission inventories. We developed a historical emission inventory in Asia for 1950-2010 base on Regional Emission Inventory in ASia (REAS) version 2. In these 6 decades, emissions of all species in Asia showed remarkable increases. Recently, the largest emitter country in Asia is China. However, in 1960s, Japan is the largest emitter country for SO2 till about 1970 and NOx till about 1980, respectively. We surveyed effectiveness of abatement measures on NOx emissions in Japan and China. In Japan, the largest effective mitigation measure is regulation for motor vehicles. In 2010, reduced amounts of NOx emissions were estimated to be 2.7 time larger than actual emissions. For China, until 2010, the most effective mitigation measure is low-NOx burner installed in power plants. Regulation of motor vehicles also assumed to reduce NOx emissions from road transport by 40% compared to those without regulations in 2010. We roughly expanded the period of NOx emissions in China and Japan till 2012 and trend between 2008 and 2012 were compared with top-down emissions estimated using inverse modeling technique and satellite observations. Compared to top-down emissions, trends of the bottom-up emissions in China (Japan) overestimated increased (decreased) ratios in 2008-2012. For China, our emissions seem to underestimate the penetration rates of FGD for NOx installed in power plants. On the other hand, decreased rates of NOx emission factors for road vehicles in Japan might be overestimated in our emissions. These differences will be reconsidered to update our bottom-up emission inventory.

  13. A Librarian's Primer on Financial Ratios.

    Science.gov (United States)

    Kerbel, Sandra Sandor

    1982-01-01

    Explains in simple terms the nature and function of a number of basic types of business and industrial financial ratios. An annotated list of five basic sources for ratios is included and a reference list and bibliography are attached. (JL)

  14. UV line emission of symbiotic stars

    International Nuclear Information System (INIS)

    Nussbaumer, H.

    1982-01-01

    General characteristics of emission line spectra from symbiotic stars are outlined. Data from some special line ratios in the 1000 A - 3000 A range, and others connecting the visual and the far UV lines are presented, and their application to symbiotic stars is discussed. Integrated fractional abundances for ions easily observed in the far UV are given to facilitate abundance determinations for nebular conditions. It is found that the physical conditions of the regions emitting the emission line spectra differ considerably among different symbiotic stars. (Auth.)

  15. Contribution to the problem of liquidity ratios

    OpenAIRE

    Dvoøáèek Jaroslav

    1997-01-01

    The article is based on the importance of the financial analysis in mining industry. The author pays attention to liquidity ratios given in literature from the standpoint of their number, content, units and recommended quantity value of single ratios. For the application in practice two liquidity ratios are suggested and the methodology of their recommended values determination is given.

  16. Relationships between breath ratios, spirituality and health ...

    African Journals Online (AJOL)

    The aim of this retrospective, quantitative study was to investigate relationships between breath ratios, spirituality perceptions and health perceptions, with special reference to breath ratios that best predict optimal health and spirituality. Significant negative correlations were found between breath ratios and spirituality ...

  17. Contribution to the problem of liquidity ratios

    Directory of Open Access Journals (Sweden)

    Dvoøáèek Jaroslav

    1997-03-01

    Full Text Available The article is based on the importance of the financial analysis in mining industry. The author pays attention to liquidity ratios given in literature from the standpoint of their number, content, units and recommended quantity value of single ratios. For the application in practice two liquidity ratios are suggested and the methodology of their recommended values determination is given.

  18. CO2 emission related to energy combustion in the world in 2006

    International Nuclear Information System (INIS)

    2009-02-01

    After a brief comment of the evolution of CO 2 emissions due to transports, housing and office buildings, industry and agriculture, electrical plants, and other energetic activities in France in 2007 in comparison with previous years, this article comments the global increase of CO 2 emissions related to energy in the world (figures and graphs are given for some countries of all continents, notably for China, the United States, France, the European Union, the United Kingdom and Germany). These emissions are then assessed in terms of ratio between emission intensity and GDPs or population. Emissions per inhabitant display a 1 to 20 ratio between the USA and Africa

  19. BP's emissions trading system

    International Nuclear Information System (INIS)

    Victor, David G.; House, Joshua C.

    2006-01-01

    Between 1998 and 2001, BP reduced its emissions of greenhouse gases by more than 10%. BP's success in cutting emissions is often equated with its use of an apparently market-based emissions trading program. However no independent study has ever examined the rules and operation of BP's system and the incentives acting on managers to reduce emissions. We use interviews with key managers and with traders in several critical business units to explore the bound of BP's success with emissions trading. No money actually changed hands when permits were traded, and the main effect of the program was to create awareness of money-saving emission controls rather than strong price incentives. We show that the trading system did not operate like a 'textbook' cap and trade scheme. Rather, the BP system operated much like a 'safety valve' trading system, where managers let the market function until the cost of doing so surpassed what the company was willing to tolerate

  20. Prompt neutron emission

    International Nuclear Information System (INIS)

    Sher, R.

    1959-01-01

    It is shown that Ramanna and Rao's tentative conclusion that prompt fission neutrons are emitted (in the fragment system) preferentially in the direction of fragment motion is not necessitated by their angular distribution measurements, which are well explained by the usual assumptions of isotropic emission with a Maxwell (or Maxwell-like) emission spectrum. The energy distribution (Watt spectrum) and the angular distribution, both including the effects of anisotropic emission, are given. (author) [fr

  1. Radio emission from Jupiter

    International Nuclear Information System (INIS)

    Velusamy, T.

    1976-01-01

    The basic features of the different radio emissions from the planet Jupiter are reviewed. These radio emissions characterized into three types as thermal, decimetric and decametric, are discussed. The coherent emission mechanism for the origin of the decametric bursts and the acceleration mechanism for relativistic electrons in the decimetric radiation have not been properly understood. The emissions are much related to the magnetic field of Jupiter. The system III rotation period for Jupiter has been calculated as 092 55 m 29.74 S. (A.K.)

  2. VOC emissions chambers

    Data.gov (United States)

    Federal Laboratory Consortium — In order to support the development of test methods and reference materials for volatile organic compounds (VOC) emissions from building materials and furnishings,...

  3. Microgravity Emissions Laboratory (MEL)

    Data.gov (United States)

    Federal Laboratory Consortium — The Microgravity Emissions Laboratory (MEL) utilizes a low-frequency acceleration measurement system for the characterization of rigid body inertial forces generated...

  4. Virtual disjunct eddy covariance measurements of organic compound fluxes from a subalpine forest using proton transfer reaction mass spectrometry

    Directory of Open Access Journals (Sweden)

    T. G. Karl

    2002-01-01

    Full Text Available A `virtual' disjunct eddy covariance (vDEC device was tested with field measurements of biogenic VOC fluxes at a subalpine forest site in the Rocky Mountains of the USA. A PTR-MS instrument was used as the VOC sensor. Daily peak emission fluxes of 2-methyl-3-buten-2-ol (MBO, methanol, acetone and acetaldehyde were around 1.5, 1, 0.8 and 0.4 mg m-2 h-1, respectively. High pass filtering due to long sampling lines was investigated in laboratory experiments, and suggested that VOC losses in PTFA lines are generally governed by diffusion laws. Memory effects and surface reactions did not seem to play a dominant role. Model estimates of MBO fluxes compared well with measured fluxes. The results also suggest that latent heat and sensible heat fluxes are reasonably well correlated with VOC fluxes and could be used to predict variations in VOC emissions. The release of MBO, methanol, acetone and acetaldehyde resulted in significant change of tropospheric oxidant levels and a 10--40% increase in ozone levels, as inferred from a photochemical box model. We conclude that vDEC with a PTR-MS instrument is a versatile tool for simultaneous field analysis of multiple VOC fluxes.

  5. IASI-derived NH3 enhancement ratios relative to CO for the tropical biomass burning regions

    Science.gov (United States)

    Whitburn, Simon; Van Damme, Martin; Clarisse, Lieven; Hurtmans, Daniel; Clerbaux, Cathy; Coheur, Pierre-François

    2017-10-01

    Vegetation fires are a major source of ammonia (NH3) in the atmosphere. Their emissions are mainly estimated using bottom-up approaches that rely on uncertain emission factors. In this study, we derive new biome-specific NH3 enhancement ratios relative to carbon monoxide (CO), ERNH3 / CO (directly related to the emission factors), from the measurements of the IASI sounder onboard the Metop-A satellite. This is achieved for large tropical regions and for an 8-year period (2008-2015). We find substantial differences in the ERNH3 / CO ratios between the biomes studied, with calculated values ranging from 7 × 10-3 to 23 × 10-3. For evergreen broadleaf forest these are typically 50-75 % higher than for woody savanna and savanna biomes. This variability is attributed to differences in fuel types and size and is in line with previous studies. The analysis of the spatial and temporal distribution of the ERNH3 / CO ratio also reveals a (sometimes large) within-biome variability. On a regional level, woody savanna shows, for example, a mean ERNH3 / CO ratio for the region of Africa south of the Equator that is 40-75 % lower than in the other five regions studied, probably reflecting regional differences in fuel type and burning conditions. The same variability is also observed on a yearly basis, with a peak in the ERNH3 / CO ratio observed for the year 2010 for all biomes. These results highlight the need for the development of dynamic emission factors that take into better account local variations in fuel type and fire conditions. We also compare the IASI-derived ERNH3 / CO ratio with values reported in the literature, usually calculated from ground-based or airborne measurements. We find general good agreement in the referenced ERNH3 / CO ratio except for cropland, for which the ERNH3 / CO ratio shows an underestimation of about 2-2.5 times.

  6. Effect Of Compression Ratio On The Performance Of Diesel Engine At Different Loads.

    OpenAIRE

    Abhishek Reddy G; Nirmal Pratap Singh

    2015-01-01

    Variable compression ratio (VCR) technology has long been recognized as a method for improving the automobile engine performance, efficiency, fuel economy with reduced emission. The main feature of the VCR engine is to operate at different compression ratio, by changing the combustion chamber volume, depending on the vehicle performance needs .The need to improve the performance characteristics of the IC Engine has necessitated the present research. Increasing the compression rati...

  7. Anomalous optical emission in hot dense oxygen

    Science.gov (United States)

    Santoro, Mario; Gregoryanz, Eugene; Mao, Ho-kwang; Hemley, Russell J.

    2007-11-01

    We report the observation of unusually strong, broad-band optical emission peaked between 590 and 650 nm when solid and fluid oxygen are heated by a near infrared laser at pressures from 3 to 46 GPa. In situ Raman spectra of oxygen were collected and corresponding temperatures were measured from the Stokes/anti-Stokes intensity ratios of vibrational transitions. The intense optical emission overwhelmed the Raman spectrum at temperatures exceeding 750 K. The spectrum was found to be much narrower than Planck-type thermal emission, and the intensity increase with input power was much steeper than expected for the thermal emission. The result places an important general caveat on calculating temperatures based on optical emission spectra in high-pressure laser-heating experiments. The intense emission in oxygen is photo-induced rather than being purely thermal, through multiphoton or multi-step single photon absorption processes related to the interaction with infrared radiation. The results suggest that short lived ionic species are induced by this laser-matter interaction.

  8. Line Ratios for Solar Wind Charge Exchange with Comets

    Energy Technology Data Exchange (ETDEWEB)

    Mullen, P. D.; Cumbee, R. S.; Lyons, D.; Shelton, R. L.; Stancil, P. C. [Department of Physics and Astronomy and the Center for Simulational Physics, University of Georgia, Athens, GA 30602 (United States); Gu, L.; Kaastra, J., E-mail: pmullen2@illinois.edu [SRON Netherlands Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrecht (Netherlands)

    2017-07-20

    Charge exchange (CX) has emerged in X-ray emission modeling as a significant process that must be considered in many astrophysical environments—particularly comets. Comets host an interaction between solar wind ions and cometary neutrals to promote solar wind charge exchange (SWCX). X-ray observatories provide astronomers and astrophysicists with data for many X-ray emitting comets that are impossible to accurately model without reliable CX data. Here, we utilize a streamlined set of computer programs that incorporate the multi-channel Landau–Zener theory and a cascade model for X-ray emission to generate cross sections and X-ray line ratios for a variety of bare and non-bare ion single electron capture (SEC) collisions. Namely, we consider collisions between the solar wind constituent bare and H-like ions of C, N, O, Ne, Na, Mg, Al, and Si and the cometary neutrals H{sub 2}O, CO, CO{sub 2}, OH, and O. To exemplify the application of this data, we model the X-ray emission of Comet C/2000 WM1 (linear) using the CX package in SPEX and find excellent agreement with observations made with the XMM-Newton RGS detector. Our analyses show that the X-ray intensity is dominated by SWCX with H, while H{sub 2}O plays a secondary role. This is the first time, to our knowledge, that CX cross sections have been implemented into a X-ray spectral fitting package to determine the H to H{sub 2}O ratio in cometary atmospheres. The CX data sets are incorporated into the modeling packages SPEX and Kronos .

  9. Assessing methods to estimate emissions of non-methane organic compounds from landfills

    DEFF Research Database (Denmark)

    Saquing, Jovita M.; Chanton, Jeffrey P.; Yazdani, Ramin

    2014-01-01

    The non-methane organic compound (NMOC) emission rate is used to assess compliance with landfill gas emission regulations by the United States Environmental Protection Agency (USEPA). A recent USEPA Report (EPA/600/R-11/033) employed a ratio method to estimate speciated NMOC emissions (i...... and speciated NMOC concentration and flux data from 2012/2013 field sampling of four landfills, an unpublished landfill study, and literature data from three landfills. The ratio method worked well for landfills with thin covers (...

  10. Atmospheric Inverse Estimates of Methane Emissions from Central California

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Chuanfeng; Andrews, Arlyn E.; Bianco, Laura; Eluszkiewicz, Janusz; Hirsch, Adam; MacDonald, Clinton; Nehrkorn, Thomas; Fischer, Marc L.

    2008-11-21

    Methane mixing ratios measured at a tall-tower are compared to model predictions to estimate surface emissions of CH{sub 4} in Central California for October-December 2007 using an inverse technique. Predicted CH{sub 4} mixing ratios are calculated based on spatially resolved a priori CH{sub 4} emissions and simulated atmospheric trajectories. The atmospheric trajectories, along with surface footprints, are computed using the Weather Research and Forecast (WRF) coupled to the Stochastic Time-Inverted Lagrangian Transport (STILT) model. An uncertainty analysis is performed to provide quantitative uncertainties in estimated CH{sub 4} emissions. Three inverse model estimates of CH{sub 4} emissions are reported. First, linear regressions of modeled and measured CH{sub 4} mixing ratios obtain slopes of 0.73 {+-} 0.11 and 1.09 {+-} 0.14 using California specific and Edgar 3.2 emission maps respectively, suggesting that actual CH{sub 4} emissions were about 37 {+-} 21% higher than California specific inventory estimates. Second, a Bayesian 'source' analysis suggests that livestock emissions are 63 {+-} 22% higher than the a priori estimates. Third, a Bayesian 'region' analysis is carried out for CH{sub 4} emissions from 13 sub-regions, which shows that inventory CH{sub 4} emissions from the Central Valley are underestimated and uncertainties in CH{sub 4} emissions are reduced for sub-regions near the tower site, yielding best estimates of flux from those regions consistent with 'source' analysis results. The uncertainty reductions for regions near the tower indicate that a regional network of measurements will be necessary to provide accurate estimates of surface CH{sub 4} emissions for multiple regions.

  11. Application of Performance Ratios in Portfolio Optimization

    Directory of Open Access Journals (Sweden)

    Aleš Kresta

    2015-01-01

    Full Text Available The cornerstone of modern portfolio theory was established by pioneer work of Harry Markowitz. Based on his mean-variance framework, Sharpe formulated his well-known Sharpe ratio aiming to measure the performance of mutual funds. The contemporary development in computer’s computational power allowed to apply more complex performance ratios, which take into account also higher moments of return probability distribution. Although these ratios were proposed to help the investors to improve the results of portfolio optimization, we empirically demonstrated in our paper that this may not necessarily be true. On the historical dataset of DJIA components we empirically showed that both Sharpe ratio and MAD ratio outperformed Rachev ratio. However, for Rachev ratio we assumed only one level of parameters value. Different set-ups of parameters may provide different results and thus further analysis is certainly required.

  12. Poisson's ratio of fiber-reinforced composites

    Science.gov (United States)

    Christiansson, Henrik; Helsing, Johan

    1996-05-01

    Poisson's ratio flow diagrams, that is, the Poisson's ratio versus the fiber fraction, are obtained numerically for hexagonal arrays of elastic circular fibers in an elastic matrix. High numerical accuracy is achieved through the use of an interface integral equation method. Questions concerning fixed point theorems and the validity of existing asymptotic relations are investigated and partially resolved. Our findings for the transverse effective Poisson's ratio, together with earlier results for random systems by other authors, make it possible to formulate a general statement for Poisson's ratio flow diagrams: For composites with circular fibers and where the phase Poisson's ratios are equal to 1/3, the system with the lowest stiffness ratio has the highest Poisson's ratio. For other choices of the elastic moduli for the phases, no simple statement can be made.

  13. PENGARUH PERUBAHAN RETURN ON ASSETS, PERUBAHAN DEBT TO EQUITY RATIO DAN PERUBAHAN CASH RATIO TERHADAP PERUBAHAN DIVIDEND PAYOUT RATIO

    Directory of Open Access Journals (Sweden)

    Yuli Soesetio

    2008-02-01

    Full Text Available Dividend Payout Ratio used to calculate all of revenue that will be accepted by stockholders as cash dividend, usually explained as percentage. This research was conducted to know several factors that affected change of Dividend Payout Ratio and to know the significance level and the correlation between dependent and independent variable. Analysis instrument used was parametric statistic. Based on the result of statistic test,  The Change of Return on Asset (X1, The Change of Debt to Equity Ratio (X2,  were able to explain dependent variable of the change Dividend Payout Ratio, and The Change of CashRatio can’t explain dependent variable of the change Dividend Payout Ratio

  14. Measurement and prediction of enteric methane emission

    Science.gov (United States)

    Sejian, Veerasamy; Lal, Rattan; Lakritz, Jeffrey; Ezeji, Thaddeus

    2011-01-01

    The greenhouse gas (GHG) emissions from the agricultural sector account for about 25.5% of total global anthropogenic emission. While CO2 receives the most attention as a factor relative to global warming, CH4, N2O and chlorofluorocarbons (CFCs) also cause significant radiative forcing. With the relative global warming potential of 25 compared with CO2, CH4 is one of the most important GHGs. This article reviews the prediction models, estimation methodology and strategies for reducing enteric CH4 emissions. Emission of CH4 in ruminants differs among developed and developing countries, depending on factors like animal species, breed, pH of rumen fluid, ratio of acetate:propionate, methanogen population, composition of diet and amount of concentrate fed. Among the ruminant animals, cattle contribute the most towards the greenhouse effect through methane emission followed by sheep, goats and buffalos, respectively. The estimated CH4 emission rate per cattle, buffaloe, sheep and goat in developed countries are 150.7, 137, 21.9 and 13.7 (g/animal/day) respectively. However, the estimated rates in developing countries are significantly lower at 95.9 and 13.7 (g/animal/day) per cattle and sheep, respectively. There exists a strong interest in developing new and improving the existing CH4 prediction models to identify mitigation strategies for reducing the overall CH4 emissions. A synthesis of the available literature suggests that the mechanistic models are superior to empirical models in accurately predicting the CH4 emission from dairy farms. The latest development in prediction model is the integrated farm system model which is a process-based whole-farm simulation technique. Several techniques are used to quantify enteric CH4 emissions starting from whole animal chambers to sulfur hexafluoride (SF6) tracer techniques. The latest technology developed to estimate CH4 more accurately is the micrometeorological mass difference technique. Because the conditions under which

  15. Outsourcing CO2 Emissions

    Science.gov (United States)

    Davis, S. J.; Caldeira, K. G.

    2009-12-01

    CO2 emissions from the burning of fossil fuels are the primary cause of global warming. Much attention has been focused on the CO2 directly emitted by each country, but relatively little attention has been paid to the amount of emissions associated with consumption of goods and services in each country. This consumption-based emissions inventory differs from the production-based inventory because of imports and exports of goods and services that, either directly or indirectly, involved CO2 emissions. Using the latest available data and reasonable assumptions regarding trans-shipment of embodied carbon through third-party countries, we developed a global consumption-based CO2 emissions inventory and have calculated associated consumption-based energy and carbon intensities. We find that, in 2004, 24% of CO2 emissions are effectively outsourced to other countries, with much of the developed world outsourcing CO2 emissions to emerging markets, principally China. Some wealthy countries, including Switzerland and Sweden, outsource over half of their consumption-based emissions, with many northern Europeans outsourcing more than three tons of emissions per person per year. The United States is both a big importer and exporter of emissions embodied in trade, outsourcing >2.6 tons of CO2 per person and at the same time as >2.0 tons of CO2 per person are outsourced to the United States. These large flows indicate that CO2 emissions embodied in trade must be taken into consideration when considering responsibility for increasing atmospheric greenhouse gas concentrations.

  16. 47 CFR 78.103 - Emissions and emission limitations.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Emissions and emission limitations. 78.103... CABLE TELEVISION RELAY SERVICE Technical Regulations § 78.103 Emissions and emission limitations. (a) A CARS station may be authorized to employ any type of emission, for which there are technical standards...

  17. Air Emission Inventory for the INEEL -- 1999 Emission Report

    Energy Technology Data Exchange (ETDEWEB)

    Zohner, Steven K

    2000-05-01

    This report presents the 1999 calendar year update of the Air Emission Inventory for the Idaho National Engineering and Environmental Laboratory (INEEL). The INEEL Air Emission Inventory documents sources and emissions of nonradionuclide pollutants from operations at the INEEL. The report describes the emission inventory process and all of the sources at the INEEL, and provides nonradionuclide emissions estimates for stationary sources.

  18. A Ratio-Analysis Method to the Dynamics of Excited State Proton Transfer: Pyranine in Water and Micelles.

    Science.gov (United States)

    Sahu, Kalyanasis; Nandi, Nilanjana; Dolai, Suman; Bera, Avisek

    2018-06-05

    Emission spectrum of a fluorophore undergoing excited state proton transfer (ESPT) often exhibits two distinct bands each representing emissions from protonated and deprotonated forms. The relative contribution of the two bands, best represented by an emission intensity ratio (R) (intensity maximum of the protonated band / intensity maximum of the deprotonated band), is an important parameter which usually denotes feasibility or promptness of the ESPT process. However, the use of ratio is only limited to the interpretation of steady-state fluorescence spectra. Here, for the first time, we exploit the time-dependence of the ratio (R(t)), calculated from time-resolved emission spectra (TRES) at different times, to analyze ESPT dynamics. TRES at different times were fitted with a sum of two lognormal-functions representing each peaks and then, the peak intensity ratio, R(t) was calculated and further fitted with an analytical function. Recently, a time-resolved area-normalized emission spectra (TRANES)-based analysis was presented where the decay of protonated emission or the rise of deprotonated emission intensity conveniently accounts for the ESPT dynamics. We show that these two methods are equivalent but the new method provides more insights on the nature of the ESPT process.

  19. Spatial variability of mixing ratios of ammonia and tracer gases in a naturally ventilated dairy cow barn

    NARCIS (Netherlands)

    Mendes, Luciano B.; Edouard, Nadège; Ogink, Nico W.M.; Dooren, van Hendrik Jan C.; Fátima F. TinÔco, de Ilda; Mosquera Losada, Julio

    2015-01-01

    The use of the tracer gas ratio method to estimate emissions from naturally ventilated (NV) livestock barns excludes the need of monitoring ventilation rates. However, it requires accurate measurement of tracer release rate (QT) and a representative estimate of the mixing ratio between

  20. Uncertainties in emission inventories

    NARCIS (Netherlands)

    Aardenne, van J.A.

    2002-01-01

    Emission inventories provide information about the amount of a pollutant that is emitted to the atmosphere as a result of a specific anthropogenic or natural process at a given time or place. Emission inventories can be used for either policy or scientific purposes. For

  1. Positron emission tomography

    International Nuclear Information System (INIS)

    Reivich, M.; Alavi, A.

    1985-01-01

    This book contains 24 selections. Some of the titles are: Positron Emission Tomography Instrumentation, Generator Systems for Positron Emitters, Reconstruction Algorithms, Cerebral Glucose Consumption: Methodology and Validation, Cerebral Blood Flow Tomography Using Xenon-133 Inhalation: Methods and Clinical Applications, PET Studies of Stroke, Cardiac Positron Emission Tomography, and Use of PET in Oncology

  2. National pollutants emission limits

    International Nuclear Information System (INIS)

    Chmielewski, A.G.; Pawelec, A.

    2011-01-01

    Fossil fuels are the main energy sources. Unfortunately the vast quantities of pollutants are emitted to the atmosphere during their combustion. These emissions lead to the environment degradation and affect human health. Therefore most of the countries have introduced the standards concerning emission control. These regulations for some countries are presented in the paper. (author)

  3. National pollutants emission limits

    Energy Technology Data Exchange (ETDEWEB)

    Chmielewski, A. G.; Pawelec, A. [Institute of Nuclear Chemistry and Technology, Warsaw (Poland)

    2011-07-01

    Fossil fuels are the main energy sources. Unfortunately the vast quantities of pollutants are emitted to the atmosphere during their combustion. These emissions lead to the environment degradation and affect human health. Therefore most of the countries have introduced the standards concerning emission control. These regulations for some countries are presented in the paper. (author)

  4. Database of emission lines

    Science.gov (United States)

    Binette, L.; Ortiz, P.; Joguet, B.; Rola, C.

    1998-11-01

    A widely accessible data bank (available through Netscape) and consiting of all (or most) of the emission lines reported in the litterature is being built. It will comprise objects as diverse as HII regions, PN, AGN, HHO. One of its use will be to define/refine existing diagnostic emission line diagrams.

  5. Simple proxies for estimating the concentrations of monoterpenes and their oxidation products at a boreal forest site

    Directory of Open Access Journals (Sweden)

    J. Kontkanen

    2016-10-01

    Full Text Available The oxidation products of monoterpenes likely have a crucial role in the formation and growth of aerosol particles in boreal forests. However, the continuous measurements of monoterpene concentrations are usually not available on decadal timescales, and the direct measurements of the concentrations of monoterpene oxidation product have so far been scarce. In this study we developed proxies for the concentrations of monoterpenes and their oxidation products at a boreal forest site in Hyytiälä, southern Finland. For deriving the proxies we used the monoterpene concentration measured with a proton transfer reaction mass spectrometer (PTR-MS during 2006–2013. Our proxies for the monoterpene concentration take into account the temperature-controlled emissions from the forest ecosystem, the dilution caused by the mixing within the boundary layer and different oxidation processes. All the versions of our proxies captured the seasonal variation of the monoterpene concentration, the typical proxy-to-measurements ratios being between 0.8 and 1.3 in summer and between 0.6 and 2.6 in winter. In addition, the proxies were able to describe the diurnal variation of the monoterpene concentration rather well, especially in summer months. By utilizing one of the proxies, we calculated the concentration of oxidation products of monoterpenes by considering their production in the oxidation and their loss due to condensation on aerosol particles. The concentration of oxidation products was found to have a clear seasonal cycle, with a maximum in summer and a minimum in winter. The concentration of oxidation products was lowest in the morning or around noon and highest in the evening. In the future, our proxies for the monoterpene concentration and their oxidation products can be used, for example, in the analysis of new particle formation and growth in boreal environments.

  6. Characterization of methane emissions from five cold heavy oil production with sands (CHOPS) facilities.

    Science.gov (United States)

    Roscioli, Joseph R; Herndon, Scott C; Yacovitch, Tara I; Knighton, W Berk; Zavala-Araiza, Daniel; Johnson, Matthew R; Tyner, David R

    2018-03-07

    Cold heavy oil production with sands (CHOPS) is a common oil extraction method in the Canadian provinces of Alberta and Saskatchewan that can result in significant methane emissions due to annular venting. Little is known about the magnitude of these emissions, nor their contributions to the regional methane budget. Here the authors present the results of field measurements of methane emissions from CHOPS wells and compare them with self-reported venting rates. The tracer ratio method was used not only to analyze total site emissions but at one site it was also used to locate primary emission sources and quantify their contributions to the facility-wide emission rate, revealing the annular vent to be a dominant source. Emissions measured from five different CHOPS sites in Alberta showed large discrepancies between the measured and reported rates, with emissions being mainly underreported. These methane emission rates are placed in the context of current reporting procedures and the role that gas-oil ratio (GOR) measurements play in vented volume estimates. In addition to methane, emissions of higher hydrocarbons were also measured; a chemical "fingerprint" associated with CHOPS wells in this region reveals very low emission ratios of ethane, propane, and aromatics versus methane. The results of this study may inform future studies of CHOPS sites and aid in developing policy to mitigate regional methane emissions. Methane measurements from cold heavy oil production with sand (CHOPS) sites identify annular venting to be a potentially major source of emissions at these facilities. The measured emission rates are generally larger than reported by operators, with uncertainty in the gas-oil ratio (GOR) possibly playing a large role in this discrepancy. These results have potential policy implications for reducing methane emissions in Alberta in order to achieve the Canadian government's goal of reducing methane emissions by 40-45% below 2012 levels within 8 yr.

  7. Observed Barium Emission Rates

    Science.gov (United States)

    Stenbaek-Nielsen, H. C.; Wescott, E. M.; Hallinan, T. J.

    1993-01-01

    The barium releases from the CRRES satellite have provided an opportunity for verifying theoretically calculated barium ion and neutral emission rates. Spectra of the five Caribbean releases in the summer of 1991 were taken with a spectrograph on board a U.S. Air Force jet aircraft. Because the line of sight release densities are not known, only relative rates could be obtained. The observed relative rates agree well with the theoretically calculated rates and, together with other observations, confirm the earlier detailed theoretical emission rates. The calculated emission rates can thus with good accuracy be used with photometric observations. It has been postulated that charge exchange between neutral barium and oxygen ions represents a significant source for ionization. If so. it should be associated with emissions at 4957.15 A and 5013.00 A, but these emissions were not detected.

  8. Hubungan Analisis Ratio Keuangan dengan Kesehatan Perusahaan

    Directory of Open Access Journals (Sweden)

    Soekarso Soekarso

    2009-09-01

    Full Text Available In the business world, companies develop a vision and mission to improve welfare in the future. The work program the company is to achieve productivity and profitability. Finance in the company is one of the strategic functions that includes wealth management and transformation of added value (added value and also the control of corporate health. The financial statements such as balance sheet (balance sheet, profit and loss statement (income statement, and financial ratio (financial ratios, reflects the company's performance and health. Financial ratio analysis relates to the health of the company through a ratio of effectiveness, efficiency, productivity, profitability, liquidity, and solvability. Analysis shows that whenever actual value of financial ratios is above standard it means the company is healthy, and when the actual value of financial ratios is below the standard, it reversely means that companies are not healthy.

  9. The HCN-Water Ratio in the Planet Formation Region of Disks

    NARCIS (Netherlands)

    Najita, J.; Carr, J.; Pontoppidan, K.; Salyk, C.; Dishoeck, van E.F.; Blake, G.

    2013-01-01

    We find a trend between the mid-infrared HCN/H$_{2}$O flux ratio and submillimeter disk mass among T Tauri stars in Taurus. While it may seem puzzling that the molecular emission properties of the inner disk ({lt}few AU) are related to the properties of the outer disk (beyond ~{}20 AU) probed by the

  10. Eccentric crank variable compression ratio mechanism

    Science.gov (United States)

    Lawrence, Keith Edward [Kobe, JP; Moser, William Elliott [Peoria, IL; Roozenboom, Stephan Donald [Washington, IL; Knox, Kevin Jay [Peoria, IL

    2008-05-13

    A variable compression ratio mechanism for an internal combustion engine that has an engine block and a crankshaft is disclosed. The variable compression ratio mechanism has a plurality of eccentric disks configured to support the crankshaft. Each of the plurality of eccentric disks has at least one cylindrical portion annularly surrounded by the engine block. The variable compression ratio mechanism also has at least one actuator configured to rotate the plurality of eccentric disks.

  11. Compilation and evaluation of a Paso del Norte emission inventory

    Energy Technology Data Exchange (ETDEWEB)

    Funk, T.H.; Chinkin, L.R.; Roberts, P.T. [Sonoma Technology, Inc., 1360 Redwood Way, Suite C, 94954-1169 Petaluma, CA (United States); Saeger, M.; Mulligan, S. [Pacific Environmental Services, 5001 S. Miami Blvd., Suite 300, 27709 Research Triangle Park, NC (United States); Paramo Figueroa, V.H. [Instituto Nacional de Ecologia, Avenue Revolucion 1425, Nivel 10, Col. Tlacopac San Angel, Delegacion Alvaro Obregon, C.P., 01040, D.F. Mexico (Mexico); Yarbrough, J. [US Environmental Protection Agency - Region 6, 1445 Ross Avenue, Suite 1200, 75202-2733 Dallas, TX (United States)

    2001-08-10

    Emission inventories of ozone precursors are routinely used as input to comprehensive photochemical air quality models. Photochemical model performance and the development of effective control strategies rely on the accuracy and representativeness of an underlying emission inventory. This paper describes the tasks undertaken to compile and evaluate an ozone precursor emission inventory for the El Paso/Ciudad Juarez/Southern Dona Ana region. Point, area and mobile source emission data were obtained from local government agencies and were spatially and temporally allocated to a gridded domain using region-specific demographic and land-cover information. The inventory was then processed using the US Environmental Protection Agency (EPA) recommended Emissions Preprocessor System 2.0 (UAM-EPS 2.0) which generates emissions files compatible with the Urban Airshed Model (UAM). A top-down evaluation of the emission inventory was performed to examine how well the inventory represented ambient pollutant compositions. The top-down evaluation methodology employed in this study compares emission inventory ratios of non-methane hydrocarbon (NMHC)/nitrogen oxide (NO{sub x}) and carbon monoxide (CO)/NO{sub x} ratios to corresponding ambient ratios. Detailed NMHC species comparisons were made in order to investigate the relative composition of individual hydrocarbon species in the emission inventory and in the ambient data. The emission inventory compiled during this effort has since been used to model ozone in the Paso del Norte airshed (Emery et al., CAMx modeling of ozone and carbon monoxide in the Paso del Norte airshed. In: Proc of Ninety-Third Annual Meeting of Air and Waste Management Association, 18-22 June 2000, Air and Waste Management Association, Pittsburgh, PA, 2000)

  12. Nebular Continuum and Line Emission in Stellar Population Synthesis Models

    Energy Technology Data Exchange (ETDEWEB)

    Byler, Nell; Dalcanton, Julianne J. [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195 (United States); Conroy, Charlie; Johnson, Benjamin D., E-mail: ebyler@astro.washington.edu [Department of Astronomy, Harvard University, Cambridge, MA 02138 (United States)

    2017-05-01

    Accounting for nebular emission when modeling galaxy spectral energy distributions (SEDs) is important, as both line and continuum emissions can contribute significantly to the total observed flux. In this work, we present a new nebular emission model integrated within the Flexible Stellar Population Synthesis code that computes the line and continuum emission for complex stellar populations using the photoionization code Cloudy. The self-consistent coupling of the nebular emission to the matched ionizing spectrum produces emission line intensities that correctly scale with the stellar population as a function of age and metallicity. This more complete model of galaxy SEDs will improve estimates of global gas properties derived with diagnostic diagrams, star formation rates based on H α , and physical properties derived from broadband photometry. Our models agree well with results from other photoionization models and are able to reproduce observed emission from H ii regions and star-forming galaxies. Our models show improved agreement with the observed H ii regions in the Ne iii/O ii plane and show satisfactory agreement with He ii emission from z = 2 galaxies, when including rotating stellar models. Models including post-asymptotic giant branch stars are able to reproduce line ratios consistent with low-ionization emission regions. The models are integrated into current versions of FSPS and include self-consistent nebular emission predictions for MIST and Padova+Geneva evolutionary tracks.

  13. OUTFLOW AND HOT DUST EMISSION IN HIGH-REDSHIFT QUASARS

    International Nuclear Information System (INIS)

    Wang, Huiyuan; Xing, Feijun; Wang, Tinggui; Zhou, Hongyan; Zhang, Kai; Zhang, Shaohua

    2013-01-01

    Correlations of hot dust emission with outflow properties are investigated, based on a large z ∼ 2 non-broad absorption line quasar sample built from the Wide-field Infrared Survey and the Sloan Digital Sky Survey data releases. We use the near-infrared slope and the infrared to UV luminosity ratio to indicate the hot dust emission relative to the emission from the accretion disk. In our luminous quasars, these hot dust emission indicators are almost independent of the fundamental parameters, such as luminosity, Eddington ratio and black hole mass, but moderately dependent on the blueshift and asymmetry index (BAI) and FWHM of C IV lines. Interestingly, the latter two correlations dramatically strengthen with increasing Eddington ratio. We suggest that, in high Eddington ratio quasars, C IV regions are dominated by outflows so the BAI and FWHM (C IV) can reliably reflect the general properties and velocity of outflows, respectively. In low Eddington ratio quasars, on the other hand, C IV lines are primarily emitted by virialized gas so the BAI and FWHM (C IV) become less sensitive to outflows. Therefore, the correlations for the highest Eddington ratio quasars are more likely to represent the true dependence of hot dust emission on outflows and the correlations for the entire sample are significantly diluted by the low Eddington ratio quasars. Our results show that an outflow with a large BAI or velocity can double the hot dust emission on average. We suggest that outflows either contain hot dust in themselves or interact with the dusty interstellar medium or torus

  14. Studying the effect of compression ratio on an engine fueled with waste oil produced biodiesel/diesel fuel

    Directory of Open Access Journals (Sweden)

    Mohammed EL_Kassaby

    2013-03-01

    Full Text Available Wasted cooking oil from restaurants was used to produce neat (pure biodiesel through transesterification, and then used to prepare biodiesel/diesel blends. The effect of blending ratio and compression ratio on a diesel engine performance has been investigated. Emission and combustion characteristics was studded when the engine operated using the different blends (B10, B20, B30, and B50 and normal diesel fuel (B0 as well as when varying the compression ratio from 14 to 16 to 18. The result shows that the engine torque for all blends increases as the compression ratio increases. The bsfc for all blends decreases as the compression ratio increases and at all compression ratios bsfc remains higher for the higher blends as the biodiesel percent increase. The change of compression ratio from 14 to 18 resulted in, 18.39%, 27.48%, 18.5%, and 19.82% increase in brake thermal efficiency in case of B10, B20, B30, and B50 respectively. On an average, the CO2 emission increased by 14.28%, the HC emission reduced by 52%, CO emission reduced by 37.5% and NOx emission increased by 36.84% when compression ratio was increased from 14 to 18. In spite of the slightly higher viscosity and lower volatility of biodiesel, the ignition delay seems to be lower for biodiesel than for diesel. On average, the delay period decreased by 13.95% when compression ratio was increased from 14 to 18. From this study, increasing the compression ratio had more benefits with biodiesel than that with pure diesel.

  15. Carbon emissions in China

    International Nuclear Information System (INIS)

    Liu, Zhu

    2016-01-01

    This study analyzes the spatial-temporal pattern and processes of China's energy-related carbon emissions. Based on extensive quantitative analysis, it outlines the character and trajectory of China's energy-related carbon emissions during the period 1995-2010, examining the distribution pattern of China's carbon emissions from regional and sectoral perspectives and revealing the driving factors of China's soaring emission increase. Further, the book investigates the supply chain carbon emissions (the carbon footprints) of China's industrial sectors. Anthropogenic climate change is one of the most serious challenges currently facing humankind. China is the world's largest developing country, top primary energy consumer and carbon emitter. Achieving both economic growth and environmental conservation is the country's twofold challenge. Understanding the status, features and driving forces of China's energy-related carbon emissions is a critical aspect of attaining global sustainability. This work, for the first time, presents both key findings on and a systematic evaluation of China's carbon emissions from energy consumption. The results have important implications for global carbon budgets and burden-sharing with regard to climate change mitigation. The book will be of great interest to readers around the world, as it addresses a topic of truly global significance.

  16. Carbon emissions in China

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Zhu [Harvard Univ., Cambridge, MA (United States). Sustainability Science Program

    2016-07-01

    This study analyzes the spatial-temporal pattern and processes of China's energy-related carbon emissions. Based on extensive quantitative analysis, it outlines the character and trajectory of China's energy-related carbon emissions during the period 1995-2010, examining the distribution pattern of China's carbon emissions from regional and sectoral perspectives and revealing the driving factors of China's soaring emission increase. Further, the book investigates the supply chain carbon emissions (the carbon footprints) of China's industrial sectors. Anthropogenic climate change is one of the most serious challenges currently facing humankind. China is the world's largest developing country, top primary energy consumer and carbon emitter. Achieving both economic growth and environmental conservation is the country's twofold challenge. Understanding the status, features and driving forces of China's energy-related carbon emissions is a critical aspect of attaining global sustainability. This work, for the first time, presents both key findings on and a systematic evaluation of China's carbon emissions from energy consumption. The results have important implications for global carbon budgets and burden-sharing with regard to climate change mitigation. The book will be of great interest to readers around the world, as it addresses a topic of truly global significance.

  17. Emissions of road transport

    International Nuclear Information System (INIS)

    Maekelae, K.; Tuominen, A.

    2001-01-01

    Information on the emissions and energy consumption of different vehicles per transported amount of goods has up to last years been minimal. The unit emissions mean the amount of harmful compounds in the flue gases of a vehicle per service, time or energy unit. National three-year MOBILE 2-research program, started in 1999, determines the unit emissions of all the traffic sectors in Finland. VTT Building and Transport mainly carry out the research, but the Institute of Transportation Engineering of the Tampere University of Technology (TTKK) is responsible for a part of the research. The objective of the project is to create common rules for the determination of unit emissions values, and to determine the best possible values for Finnish conditions. Unit emission data is mainly needed for evaluation of the environmental impacts of production plants and other activities containing transportation of commodities. At the web sites of VTT Building and Transport there are about 60 pages of text and tables (about 4000 values) on unit emissions. The URL of the pages is http://www.vtt.fi/rte/projects/lipastoe/index.htm. These web pages present data on all the transportation sectors (road, railroad, water and air transportation), most of the materials concerning road transportation. Following compounds and values are included: CO, HC, NO x , particulates, SO 2 , CO 2 and energy consumption. Methane and nitrous oxide emissions values have also been presented

  18. Greenhouse Gas Emissions From Cattle

    Directory of Open Access Journals (Sweden)

    Podkówka Zbigniew

    2015-03-01

    Full Text Available Cattle produce greenhouse gases (GHG which lead to changes in the chemical composition of the atmosphere. These gases which cause greenhouse effect include: methane (CH4, nitrous oxide (N2O, nitrogen oxides (NOx, sulphur dioxide (SO2, ammonia (NH3, dust particles and non-methane volatile organic compounds, commonly described as other than methane hydrocarbons. Fermentation processes taking place in the digestive tract produce ‘digestive gases’, distinguished from gases which are emitted during the decomposition of manure. Among these digestive gases methane and non-methane volatile organic compounds are of particular relevance importance. The amount of gases produced by cows can be reduced by choosing to rear animals with an improved genetically based performance. A dairy cow with higher production efficiency, producing milk with higher protein content and at the same time reduced fat content emits less GHG into the environment. Increasing the ratio of feed mixtures in a feed ration also reduces GHG emissions, especially of methane. By selection of dairy cows with higher production efficiency and appropriate nutrition, the farm's expected milk production target can be achieved while at the same time, the size of the herd is reduced, leading to a reduction of GHG emissions.

  19. Electronic Reporting of Air Emissions

    Science.gov (United States)

    EPA regulations require affected sources to perform emissions source tests, conduct continuous emissions monitoring, and submit compliance and emissions reports. This site provides technical resources and access for providing such submissions.

  20. Biogenic Emission Inventory System (BEIS)

    Science.gov (United States)

    Biogenic Emission Inventory System (BEIS) estimates volatile organic compound (VOC) emissions from vegetation and nitric oxide (NO) emission from soils. Recent BEIS development has been restricted to the SMOKE system

  1. National Greenhouse Gas Emission Inventory

    Data.gov (United States)

    U.S. Environmental Protection Agency — The National Greenhouse Gas Emission Inventory contains information on direct emissions of greenhouse gases as well as indirect or potential emissions of greenhouse...

  2. Emission sources and quantities

    International Nuclear Information System (INIS)

    Heinen, B.

    1991-01-01

    The paper examines emission sources and quantities for SO 2 and NO x . Natural SO 2 is released from volcanic sources and to a much lower extent from marsh gases. In nature NO x is mainly produced in the course of the chemical and bacterial denitrification processes going on in the soil. Manmade pollutants are produced in combustion processes. The paper concentrates on manmade pollution. Aspects discussed include: mechanism of pollution development; manmade emission sources (e.g. industry, traffic, power plants and domestic sources); and emission quantities and forecasts. 11 refs., 2 figs., 5 tabs

  3. Quantification in emission tomography

    International Nuclear Information System (INIS)

    Buvat, Irene

    2011-11-01

    The objective of this lecture is to understand the possibilities and limitations of the quantitative analysis of single photon emission computed tomography (SPECT) and positron emission tomography (PET) images. It is also to identify the conditions to be fulfilled to obtain reliable quantitative measurements from images. Content: 1 - Introduction: Quantification in emission tomography - definition and challenges; quantification biasing phenomena 2 - Main problems impacting quantification in PET and SPECT: problems, consequences, correction methods, results (Attenuation, scattering, partial volume effect, movement, un-stationary spatial resolution in SPECT, fortuitous coincidences in PET, standardisation in PET); 3 - Synthesis: accessible efficiency, know-how, Precautions, beyond the activity measurement

  4. Single photon emission tomography

    International Nuclear Information System (INIS)

    Buvat, Irene

    2011-09-01

    The objective of this lecture is to present the single photon emission computed tomography (SPECT) imaging technique. Content: 1 - Introduction: anatomic, functional and molecular imaging; Principle and role of functional or molecular imaging; 2 - Radiotracers: chemical and physical constraints, main emitters, radioisotopes production, emitters type and imaging techniques; 3 - Single photon emission computed tomography: gamma cameras and their components, gamma camera specifications, planar single photon imaging characteristics, gamma camera and tomography; 4 - Quantification in single photon emission tomography: attenuation, scattering, un-stationary spatial resolution, partial volume effect, movements, others; 5 - Synthesis and conclusion

  5. Corporate prediction models, ratios or regression analysis?

    NARCIS (Netherlands)

    Bijnen, E.J.; Wijn, M.F.C.M.

    1994-01-01

    The models developed in the literature with respect to the prediction of a company s failure are based on ratios. It has been shown before that these models should be rejected on theoretical grounds. Our study of industrial companies in the Netherlands shows that the ratios which are used in

  6. Maternal preconception diet and the sex ratio

    NARCIS (Netherlands)

    Cramer, J.S.; Lumey, L.H.

    2009-01-01

    Temporal variations in the sex ratio or the ratio of boys over girls at birth have been widely studied and variously attributed to social changes, conditions of war, and environmental changes. Recently, Mathews, Johnson and Neil (2008) studied the direct evidence of individual pregnancies and

  7. The Golden Ratio--A Contrary Viewpoint

    Science.gov (United States)

    Falbo, Clement

    2005-01-01

    Many assertions about the occurrence of the golden ratio phi in art, architecture, and nature have been shown to be false, unsupported, or misleading. For instance, we show that the spirals found in sea shells, in particular the "Nautilus pompilius," are not in the shape of the golden ratio, as is often claimed. Some of the most interesting…

  8. Osmosis and Surface Area to Volume Ratio.

    Science.gov (United States)

    Barrett, D. R. B.

    1984-01-01

    Describes an experiment designed to help students understand the concepts of osmosis and surface area to volume ratio (SA:VOL). The task for students is to compare water uptake in different sizes of potato cubes and relate differences to their SA:VOL ratios. (JN)

  9. Key financial ratios can foretell hospital closures.

    Science.gov (United States)

    Lynn, M L; Wertheim, P

    1993-11-01

    An analysis of various financial ratios sampled from open and closed hospitals shows that certain leverage, liquidity, capital efficiency, and resource availability ratios can predict hospital closure up to two years in advance of the closure with an accuracy of nearly 75 percent.

  10. Charge ratio of muons from atmospheric neutrinos

    Energy Technology Data Exchange (ETDEWEB)

    Gaisser, T.K.; Stanev, Todor

    2003-05-22

    We calculate the intensities and angular distributions of positive and negative muons produced by atmospheric neutrinos. We comment on some sources of uncertainty in the charge ratio. We also draw attention to a potentially interesting signature of neutrino oscillations in the muon charge ratio, and we discuss the prospects for its observation (which are not quite within the reach of currently planned magnetized detectors)

  11. Maternal preconception diet and the sex ratio

    NARCIS (Netherlands)

    Cramer, J.S.; Lumey, L.H.

    2010-01-01

    Temporal variations in the sex ratio, or the ratio of boys to girls at birth, have been widely studied and variously attributed to social changes, conditions of war, and environmental changes. Recently, Mathews et al. ["You are what your mother eats: Evidence for maternal preconception diet

  12. Financial Ratio Analysis Comes to Nonprofits.

    Science.gov (United States)

    Chabotar, Kent John

    1989-01-01

    To evaluate their financial health, a growing number of colleges, universities, and other nonprofit organizations are using financial ratio analysis, a technique used in business. The strengths and weaknesses of ratio analysis are assessed and suggestions are made on how nonprofits can use it most effectively. (Author/MLW)

  13. Curious Sex Ratios and Cytoplasmic Genes

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 2; Issue 6. Curious Sex Ratios and Cytoplasmic Genes Microbes Can Distort the Sex Ratio of Populations. Stephen J Freeland Laurence D Hurst. General Article Volume 2 Issue 6 June 1997 pp 68-78 ...

  14. Millimeter-wave Line Ratios and Sub-beam Volume Density Distributions

    Energy Technology Data Exchange (ETDEWEB)

    Leroy, Adam K.; Gallagher, Molly [Department of Astronomy, The Ohio State University, 140 West 18th Avenue, Columbus, OH 43210 (United States); Usero, Antonio [Observatorio Astronmico Nacional (IGN), C/Alfonso XII, 3, E-28014 Madrid (Spain); Schruba, Andreas [Max-Planck-Institut für extraterrestrische Physik, Giessenbachstraße 1, D-85748 Garching (Germany); Bigiel, Frank [Institute für theoretische Astrophysik, Zentrum für Astronomie der Universität Heidelberg, Albert-Ueberle Str. 2, D-69120 Heidelberg (Germany); Kruijssen, J. M. Diederik; Schinnerer, Eva [Astronomisches Rechen-Institut, Zentrum für Astronomie der Universität Heidelberg, Mönchhofstraße 12-14, D-69120 Heidelberg (Germany); Kepley, Amanda [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States); Blanc, Guillermo A. [Departamento de Astronomía, Universidad de Chile, Casilla 36-D, Santiago (Chile); Bolatto, Alberto D. [Department of Astronomy, Laboratory for Millimeter-wave Astronomy, and Joint Space Institute, University of Maryland, College Park, MD 20742 (United States); Cormier, Diane; Jiménez-Donaire, Maria J. [Max Planck Institute für Astronomie, Königstuhl 17, D-69117, Heidelberg (Germany); Hughes, Annie [CNRS, IRAP, 9 av. du Colonel Roche, BP 44346, F-31028 Toulouse cedex 4 (France); Rosolowsky, Erik [Department of Physics, University of Alberta, Edmonton, AB (Canada)

    2017-02-01

    We explore the use of mm-wave emission line ratios to trace molecular gas density when observations integrate over a wide range of volume densities within a single telescope beam. For observations targeting external galaxies, this case is unavoidable. Using a framework similar to that of Krumholz and Thompson, we model emission for a set of common extragalactic lines from lognormal and power law density distributions. We consider the median density of gas that produces emission and the ability to predict density variations from observed line ratios. We emphasize line ratio variations because these do not require us to know the absolute abundance of our tracers. Patterns of line ratio variations have the potential to illuminate the high-end shape of the density distribution, and to capture changes in the dense gas fraction and median volume density. Our results with and without a high-density power law tail differ appreciably; we highlight better knowledge of the probability density function (PDF) shape as an important area. We also show the implications of sub-beam density distributions for isotopologue studies targeting dense gas tracers. Differential excitation often implies a significant correction to the naive case. We provide tabulated versions of many of our results, which can be used to interpret changes in mm-wave line ratios in terms of adjustments to the underlying density distributions.

  15. Fast sorption measurements of volatile organic compounds on building materials: Part 1 – Methodology developed for field applications

    Directory of Open Access Journals (Sweden)

    M. Rizk

    2016-03-01

    Full Text Available A Proton Transfer Reaction-Mass Spectrometer (PTR-MS has been coupled to the outlet of a Field and Laboratory Emission Cell (FLEC, to measure volatile organic compounds (VOC concentration during a sorption experiments (Rizk et al., this issue [1]. The limits of detection of the PTR-MS for three VOCs are presented for different time resolution (2, 10 and 20 s. The mass transfer coefficient was calculated in the FLEC cavity for the different flow rates. The concentration profile obtained from a sorption experiment performed on a gypsum board and a vinyl flooring are also presented in comparison with the profile obtained for a Pyrex glass used as a material that do not present any sorption behavior (no sink. Finally, the correlation between the concentration of VOCs adsorbed on the surface of the gypsum board at equilibrium (Cse and the concentration of VOCs Ce measured in the gas phase at equilibrium is presented for benzene, C8 aromatics and toluene.

  16. Flux measurement of methanol, acetaldehyde and other oxygenated VOCs from crop harvesting using proton-transfer-reaction mass spectrometry and surface layer gradient method

    International Nuclear Information System (INIS)

    Lindinger, C.; Jordan, A.; Karl, T.; Guenther, A.; Tschiersch, J.; Ruckerbauer, F.; Paretzke, H.

    2002-01-01

    PTR-MS technique was used to measure fluxes of various VOC's including oxygenates using surface layer gradient method. The VOC concentrations and temperature were measured at heights of about 0.5 m and 3.9 m above ground at field site in St. Johann in Tirol during and after grass cutting (24th and 25th of May 2000) in order to calculate fluxes. The sensible heat flux was obtained by a sonic anemometer with turbulence data analyzer. The major crop in this part of Austria are perennial grasses used for livestock farming. We observed VOC emission fluxes including methanol and acetaldehyde as the major volatile, C 5 and C 6 leaf wound compounds with lesser amounts and traces of acetone and butanone. This composition of VOC's is very similar to that released from slashed pasture grass. At the same time, VOC fluxes were measured with PTR-MS and eddy covariance method. Comparing the flux data of methanol and acetaldehyde of both days have shown very similar results. (author)

  17. Ratio of the Core to the Extended Emissions in the Comoving Frame ...

    Indian Academy of Sciences (India)

    Yun-Tian Li

    2017-06-19

    Jun 19, 2017 ... 2Department of Physics, School for Physics and Electronic Engineering, Guangzhou University, ... Research Laboratory of Department of Education of Guangdong ...... 11403006), and the Innovation Foundation of Guang-.

  18. High Turndown Ratio, High Delta-Emittance, Variable Emissivity Electrochromics, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Variable-emittance materials are in high demand for applications ranging from manned and unmanned space platforms (e.g. in radiators at the Moon's poles where damage...

  19. Geometrical scaling in charm structure function ratios

    International Nuclear Information System (INIS)

    Boroun, G.R.; Rezaei, B.

    2014-01-01

    By using a Laplace-transform technique, we solve the next-to-leading-order master equation for charm production and derive a compact formula for the ratio R c =F L cc ¯ /F 2 cc ¯ , which is useful for extracting the charm structure function from the reduced charm cross section, in particular, at DESY HERA, at small x. Our results show that this ratio is independent of x at small x. In this method of determining the ratios, we apply geometrical scaling in charm production in deep inelastic scattering (DIS). Our analysis shows that the renormalization scales have a sizable impact on the ratio R c at high Q 2 . Our results for the ratio of the charm structure functions are in a good agreement with some phenomenological models

  20. Equity Theory Ratios as Causal Schemas

    Directory of Open Access Journals (Sweden)

    Alexios Arvanitis

    2016-08-01

    Full Text Available Equity theory approaches justice evaluations based on ratios of exchange inputs to exchange outcomes. Situations are evaluated as just if ratios are equal and unjust if unequal. We suggest that equity ratios serve a more fundamental cognitive function than the evaluation of justice. More particularly, we propose that they serve as causal schemas for exchange outcomes, that is, they assist in determining whether certain outcomes are caused by inputs of other people in the context of an exchange process. Equality or inequality of ratios in this sense points to an exchange process. Indeed, Study 1 shows that different exchange situations, such as disproportional or balanced proportional situations, create perceptions of give-and-take on the basis of equity ratios. Study 2 shows that perceptions of justice are based more on communicatively accepted rules of interaction than equity-based evaluations, thereby offering a distinction between an attribution and an evaluation cognitive process for exchange outcomes.

  1. Equity Theory Ratios as Causal Schemas.

    Science.gov (United States)

    Arvanitis, Alexios; Hantzi, Alexandra

    2016-01-01

    Equity theory approaches justice evaluations based on ratios of exchange inputs to exchange outcomes. Situations are evaluated as just if ratios are equal and unjust if unequal. We suggest that equity ratios serve a more fundamental cognitive function than the evaluation of justice. More particularly, we propose that they serve as causal schemas for exchange outcomes, that is, they assist in determining whether certain outcomes are caused by inputs of other people in the context of an exchange process. Equality or inequality of ratios in this sense points to an exchange process. Indeed, Study 1 shows that different exchange situations, such as disproportional or balanced proportional situations, create perceptions of give-and-take on the basis of equity ratios. Study 2 shows that perceptions of justice are based more on communicatively accepted rules of interaction than equity-based evaluations, thereby offering a distinction between an attribution and an evaluation cognitive process for exchange outcomes.

  2. Independent isomer yield ratio of 90Rb

    International Nuclear Information System (INIS)

    Reeder, P.L.; Warner, R.A.; Ford, G.P.; Willmes, H.

    1985-05-01

    The independent isomer yield ratio for 90 Rb from thermal neutron fission of 235 U has been measured by use of a new technique involving a pulsed reactor and an on-line mass spectrometer facility. The apparent isomer yield ratio was measured for different ion collection time intervals and extrapolated to zero collection time to eliminate interference from 90 Kr decay. The observed isomer yield ratio of 8.7 +- 1.0 is one of the largest ratios measured for a low energy fission process. However, a statistical model analysis shows that the average angular momentum ( = 4.5) deduced from this isomer yield ratio is consistent with average angular momentum for other products from low energy fission. 7 refs

  3. THE EFFECT OF COMPRESSION RATIO VARIATIONS ON THE ENGINE PERFORMANCE PARAMETRES IN SPARK IGNITION ENGINES

    Directory of Open Access Journals (Sweden)

    Yakup SEKMEN

    2005-01-01

    Full Text Available Performance of the spark ignition engines may be increased by changing the geometrical compression ratio according to the amount of charging in cylinders. The designed geometrical compression ratio can be realized as an effective compression ratio under the full load and full open throttle conditions since the effective compression ratio changes with the amount of charging into the cylinder in spark ignition engines. So, this condition of the spark ignition engines forces designers to change their geometrical compression ratio according to the amount of charging into the cylinder for improvement of performance and fuel economy. In order to improve the combustion efficiency, fuel economy, power output, exhaust emissions at partial loads, compression ratio must be increased; but, under high load and low speed conditions to prevent probable knock and hard running the compression ratio must be decreased gradually. In this paper, relation of the performance parameters to compression ratio such as power, torque, specific fuel consumption, cylindir pressure, exhaust gas temperature, combustion chamber surface area/volume ratio, thermal efficiency, spark timing etc. in spark ignition engines have been investigated and using of engines with variable compression ratio is suggested to fuel economy and more clear environment.

  4. Energy ratios in Finnish agricultural production

    Directory of Open Access Journals (Sweden)

    H. J. MIKKOLA

    2008-12-01

    Full Text Available The objective of this study was to assess energy ratios and net energy in plant production and energy ratios in animal production in Finland. Energy ratios and net energy were determined on the basis of plant- and animal-specific energy analyses. In plant production, energy ratios and net energy were assessed as a function of nitrogen fertilization, because indirect energy input in the form of agrochemicals was 54—73% from the total energy input and nitrogen was responsible for the major part of this. The highest energy ratio was 18.6 for reed canary grass. As a whole reed canary grass was superior to the other crops, which were barley, spring wheat, spring turnip rape, ley for silage, potato and sugar beet. Reed canary grass and sugar beet gained the highest net energy yields of 111–115 GJ ha-1. The optimum energy ratio was gained in general with less nitrogen fertilization intensity than farmers use. The energy ratios in pork production varied between 0.14–1.28 depending on what was included or excluded in the analysis and for milk production between 0.15–1.85. Ratios of 1.28 in pork production and 1.85 in milk production are unrealistic as they do not give any shelter to the animals, although they can be approached in very low-input production systems. If the ratio is calculated with feed energy content then the ratio is low, 0.14–0.22 for pork and 0.15 for milk. This shows that animals can convert 14–22 percent of the input energy to usable products. In pork production, the largest portion of the energy input was the ventilation of the building. In milk production milking and cooling consumes a lot of energy and for this reason the electricity consumption is high.;

  5. Electron field emission for ultrananocrystalline diamond films

    Energy Technology Data Exchange (ETDEWEB)

    Krauss, A. R.; Auciello, O.; Ding, M. Q.; Gruen, D. M.; Huang, Y.; Zhirnov, V. V.; Givargizov, E. I.; Breskin, A.; Chechen, R.; Shefer, E. (and others)

    2001-03-01

    Ultrananocrystalline diamond (UNCD) films 0.1--2.4 {mu}m thick were conformally deposited on sharp single Si microtip emitters, using microwave CH{sub 4}--Ar plasma-enhanced chemical vapor deposition in combination with a dielectrophoretic seeding process. Field-emission studies exhibited stable, extremely high (60--100 {mu}A/tip) emission current, with little variation in threshold fields as a function of film thickness or Si tip radius. The electron emission properties of high aspect ratio Si microtips, coated with diamond using the hot filament chemical vapor deposition (HFCVD) process were found to be very different from those of the UNCD-coated tips. For the HFCVD process, there is a strong dependence of the emission threshold on both the diamond coating thickness and Si tip radius. Quantum photoyield measurements of the UNCD films revealed that these films have an enhanced density of states within the bulk diamond band gap that is correlated with a reduction in the threshold field for electron emission. In addition, scanning tunneling microscopy studies indicate that the emission sites from UNCD films are related to minima or inflection points in the surface topography, and not to surface asperities. These data, in conjunction with tight binding pseudopotential calculations, indicate that grain boundaries play a critical role in the electron emission properties of UNCD films, such that these boundaries: (a) provide a conducting path from the substrate to the diamond--vacuum interface, (b) produce a geometric enhancement in the local electric field via internal structures, rather than surface topography, and (c) produce an enhancement in the local density of states within the bulk diamond band gap.

  6. National Emission Inventory (NEI)

    Data.gov (United States)

    U.S. Environmental Protection Agency — This data exchange allows states to submit data to the US Environmental Protection Agency's National Emissions Inventory (NEI). NEI is a national database of air...

  7. 2011 NATA - Emissions Sources

    Data.gov (United States)

    U.S. Environmental Protection Agency — This dataset includes all emissions sources that were modeled in the 2011 National Air Toxics Assessment (NATA), inlcluding point, nonpoint, and mobile sources, and...

  8. Cardiac positron emission tomography

    International Nuclear Information System (INIS)

    Eftekhari, M.; Ejmalian, G.

    2003-01-01

    Positron emission tomography is an intrinsically tool that provide a unique and unparalleled approach for clinicians and researchers to interrogate the heart noninvasively. The ability to label substances of physiological interest with positron-emitting radioisotopes has permitted insight into normal blood flow and metabolism and the alterations that occur with disease states. Positron emission tomography of the heart has evolved as a unique, noninvasive approach for the assessment of myocardial perfusion, metabolism, and function. Because of the intrinsic quantitative nature of positron emission tomography measurements as well as the diverse compounds that can be labeled with positron- emitting radioisotopes, studies with positron emission tomography have provided rich insight into the physiology of the heart under diverse conditions

  9. Pulsar Emission Spectrum

    OpenAIRE

    Gruzinov, Andrei

    2013-01-01

    Emission spectrum is calculated for a weak axisymmetric pulsar. Also calculated are the observed spectrum, efficiency, and the observed efficiency. The underlying flow of electrons and positrons turns out to be curiously intricate.

  10. Biogenic Emission Sources

    Science.gov (United States)

    Biogenic emissions sources come from natural sources and need to accounted for in photochemical grid models. They are computed using a model which utilizes spatial information on vegetation and land use.

  11. Photon enhanced thermionic emission

    Science.gov (United States)

    Schwede, Jared; Melosh, Nicholas; Shen, Zhixun

    2014-10-07

    Photon Enhanced Thermionic Emission (PETE) is exploited to provide improved efficiency for radiant energy conversion. A hot (greater than 200.degree. C.) semiconductor cathode is illuminated such that it emits electrons. Because the cathode is hot, significantly more electrons are emitted than would be emitted from a room temperature (or colder) cathode under the same illumination conditions. As a result of this increased electron emission, the energy conversion efficiency can be significantly increased relative to a conventional photovoltaic device. In PETE, the cathode electrons can be (and typically are) thermalized with respect to the cathode. As a result, PETE does not rely on emission of non-thermalized electrons, and is significantly easier to implement than hot-carrier emission approaches.

  12. Positron emission tomography

    International Nuclear Information System (INIS)

    Iio, Masahiro

    1982-01-01

    Utilization of positron emission tomography was reviewed in relation to construction and planned construction of small-size medical cyclotrons, planned construction of positron cameras and utilization of short-lived radionuclides. (Chiba, N.)

  13. Radiated Emissions Test Approach

    Science.gov (United States)

    2015-10-02

    1. Draft Department of Transportation (DOT) Test Plan to Develop : Interference Tolerance Masks for GNSS Receivers in the L1 : Radiofrequency Band (1559 1610 MHz) provides high level : overview of radiated emissions test setup : 2. Presenta...

  14. Nanoscale Terahertz Emission Spectroscopy

    DEFF Research Database (Denmark)

    Pedersen, Pernille Klarskov; Kim, Hyewon; Colvin, Vicki L.

    By utilizing plasmonic coupling to an AFM probe, we demonstrate Laser Terahertz Emission Nanoscopy (LTEN) with sub-20 nm resolution. We demonstrate the resolution by imaging a single gold nanorod on an InAs substrate....

  15. Role of de novo biosynthesis in ecosystem scale monoterpene emissions from a boreal Scots pine forest

    Directory of Open Access Journals (Sweden)

    R. Taipale

    2011-08-01

    Full Text Available Monoterpene emissions from Scots pine have traditionally been assumed to originate as evaporation from specialized storage pools. More recently, the significance of de novo emissions, originating directly from monoterpene biosynthesis, has been recognized. To study the role of biosynthesis at the ecosystem scale, we measured monoterpene emissions from a Scots pine dominated forest in southern Finland using the disjunct eddy covariance method combined with proton transfer reaction mass spectrometry. The interpretation of the measurements was based on a correlation analysis and a hybrid emission algorithm describing both de novo and pool emissions. During the measurement period May–August 2007, the monthly medians of daytime emissions were 200, 290, 180, and 200 μg m−2 h−1. The emissions were partly light dependent, probably due to de novo biosynthesis. The emission potential for both de novo and pool emissions exhibited a decreasing summertime trend. The ratio of the de novo emission potential to the total emission potential varied between 30 % and 46 %. Although the monthly changes were not significant, the ratio always differed statistically from zero, suggesting that the role of de novo biosynthesis was observable. Given the uncertainties in this study, we conclude that more accurate estimates of the contribution of de novo emissions are required for improving monoterpene emission algorithms for Scots pine dominated forests.

  16. Emission spectrochemical analysis

    International Nuclear Information System (INIS)

    Rives, R.D.; Bruks, R.R.

    1983-01-01

    The emission spectrochemical method of analysis based on the fact that atoms of elements can be excited in the electric arc or in the laser beam and will emit radiation with characteristic wave lengths is considered. The review contains the data on spectrochemical analysis, of liquids geological materials, scheme of laser microprobe. The main characteristics of emission spectroscopy, atomic absorption spectroscopy and X-ray fluorescent analysis, are aeneralized

  17. Positron emission tomography

    International Nuclear Information System (INIS)

    Chandrasekhar, Preethi; Himabindu, Pucha

    2000-01-01

    Positron Emission Tomography (PET) is a non-invasive nuclear imaging technique used to study different molecular pathways and anatomical structures. PET has found extensive applications in various fields of medicine viz. cardiology, oncology, psychiatry/psychology, neuro science and pulmonology. This study paper basically deals with the physics, chemistry and biology behind the PET technique. It discusses the methodology for generation of the radiotracers responsible for emission of positrons and the annihilation and detection techniques. (author)

  18. Positron emission tomography

    International Nuclear Information System (INIS)

    Dvorak, O.

    1989-01-01

    The principle is briefly described of positron emission tomography, and its benefits and constraints are listed. It is emphasized that positron emission tomography (PET) provides valuable information on metabolic changes in the organism that are otherwise only very difficult to obtain, such as brain diagnosis including relationships between mental disorders and the physiology and pathophysiology of the brain. A PET machine is to be installed in Czechoslovakia in the near future. (L.O.)

  19. Development of net energy ratio for quad-generation pathways

    DEFF Research Database (Denmark)

    Rudra, Souman; Rosendahl, Lasse; Kumar, Amit

    2012-01-01

    The conversion of biomass to four different outputs via gasification and catalytic methanation is a renewable technology that could reduce the use of fossil fuels and GHG emissions. This study investigates the energy aspects of producing electricity, heat, methanol and methane. The Gas Technology...... Institute (GTI) gasifier and Circulating Fluidized Bed (CFB) technologies are used for this quad generation process. Three different biomass feedstocks are considered in this study. The net energy ratio for six different pathways having the range of between 1.3–9.3. The lowest limit corresponds to the straw......-based power, heat, methanol and methane production pathway using GTI technology. Since more efficient alternatives exist for the generation of heat and electricity from biomass, it is argued that syngas is best used for methanol production. The aim of this study was to evaluate the energy performance...

  20. Emissions characteristics of higher alcohol/gasoline blends

    International Nuclear Information System (INIS)

    Gautam, M.; Martin, D.W.; Carder, D.

    2000-01-01

    An experimental investigation was conducted to determine the emissions characteristics of higher alcohols and gasoline (UTG96) blends. While lower alcohols (methanol and ethanol) have been used in blends with gasoline, very little work has been done or reported on higher alcohols (propanol, butanol and pentanol). Comparisons of emissions and fuel characteristics between higher alcohol/gasoline blends and neat gasoline were made to determine the advantages and disadvantages of blending higher alcohols with gasoline. All tests were conducted on a single-cylinder Waukesha Cooperative Fuel Research engine operating at steady state conditions and stoichiometric air-fuel (A/F) ratio. Emissions test were conducted at the optimum spark timing-knock limiting compression ratio combination for the particular blend being tested. The cycle emission [mass per unit time (g/h)] of CO, CO 2 and organic matter hydrocarbon equivalent (OMHCE) from the higher alcohol/gasoline blends were very similar to those from neat gasoline. Cycle emissions of NO x from the blends were higher than those from neat gasoline. However, for all the emissions species considered, the brake specific emissions (g/kW h) were significantly lower for the higher alcohol/gasoline blends than for neat gasoline. This was because the blends had greater resistance to knock and allowed higher compression ratios, which increased engine power output. The contribution of alcohols and aldehydes to the overall OMHCE emissions was found to be minimal. Cycle fuel consumption (g/h) of higher alcohol/gasoline blends was slightly higher than with neat gasoline due to the lower stoichiometric A/F ratios required by the blends. However, the brake specific fuel consumption (g/kW h) for the blends was significantly lower than that for neat gasoline. (Author)

  1. Emission of greenhouse gases from controlled incineration of cattle manure.

    Science.gov (United States)

    Oshita, Kazuyuki; Sun, Xiucui; Taniguchi, Miki; Takaoka, Masaki; Matsukawa, Kazutsugu; Fujiwara, Taku

    2012-01-01

    Greenhouse gas emission is a potential limiting factor in livestock farming development. While incineration is one approach to minimize livestock manure, there are concerns about significant levels of nitrogen and organic compounds in manure as potential sources of greenhouse gas emissions (N2O and CH4). In this study, the effects of various incineration conditions, such as the furnace temperature and air ratio on N2O and CH4 formation behaviour, of cattle manure (as a representative livestock manure) were investigated in a pilot rotary kiln furnace. The results revealed that N2O emissions decreased with increasing temperature and decreasing air ratio. In addition, CH4 emissions tended to be high above 800 degrees C at a low air ratio. The emission factors for N2O and CH4 under the general conditions (combustion temperature of 800-850 degrees C and air ratio of 1.4) were determined to be 1.9-6.0% g-N2O-N/g-N and 0.0046-0.26% g-CH4/g-burning object, respectively. The emission factor for CH4 differed slightly from the published values between 0.16 and 0.38% g-CH4/g-burning object. However, the emission factor for N2O was much higher than the currently accepted value of 0.7% g-N2O-N/g-N and, therefore, it is necessary to revise the N2O emission factor for the incineration of livestock manure.

  2. Radioactive decay of 223Ra by 14C emission

    International Nuclear Information System (INIS)

    Yashita, S.; Gregorich, K.; Ghiorso, A.

    1985-01-01

    Recently H.J. Rose and G.A. Jones at the University of Oxford reported the very difficult observation of an exotic radioactive decay mode in 233 Ra, its spontaneous disintegration by the emission of 14 C particles. The authors have confirmed their somewhat surprising discovery by an independent method. Within the present experimental accuracy the magnetic rigidity, energy and branching ratio support the assignment of 14 C emission from 223 Ra as proposed by the Oxford experiment

  3. Comparing computing formulas for estimating concentration ratios

    International Nuclear Information System (INIS)

    Gilbert, R.O.; Simpson, J.C.

    1984-03-01

    This paper provides guidance on the choice of computing formulas (estimators) for estimating concentration ratios and other ratio-type measures of radionuclides and other environmental contaminant transfers between ecosystem components. Mathematical expressions for the expected value of three commonly used estimators (arithmetic mean of ratios, geometric mean of ratios, and the ratio of means) are obtained when the multivariate lognormal distribution is assumed. These expressions are used to explain why these estimators will not in general give the same estimate of the average concentration ratio. They illustrate that the magnitude of the discrepancies depends on the magnitude of measurement biases, and on the variances and correlations associated with spatial heterogeneity and measurement errors. This paper also reports on a computer simulation study that compares the accuracy of eight computing formulas for estimating a ratio relationship that is constant over time and/or space. Statistical models appropriate for both controlled spiking experiments and observational field studies for either normal or lognormal distributions are considered. 24 references, 15 figures, 7 tables

  4. Introducing optional reserve ratios in Hungary

    OpenAIRE

    Lóránt Varga

    2010-01-01

    As of the reserve maintenance period commencing in November 2010, Hungarian credit institutions will be free to decide whether to apply the previously valid 2% reserve ratio, or to apply a higher mandatory reserve ratio. Credit institutions required to hold reserves may select from reserve ratios of 2, 3, 4 and 5%, and may change their decision on a semi-annual basis. In line with the international best practice, the purpose of the MNB’s reserve requirement system is to support credit institu...

  5. Transcription and the aspect ratio of DNA

    DEFF Research Database (Denmark)

    Olsen, Kasper Wibeck; Bohr, Jakob

    2013-01-01

    analysis of transcription. It is shown that under certain reasonable assumptions transcription is only possible if the aspect ratio is in the regime corresponding to further twisting. We find this constraint to be in agreement with long-established crystallographic studies of DNA.......Two separate regimes exist for the aspect ratio of DNA. A low aspect regime where DNA will twist further under strain and a high aspect regime where DNA will untwist under strain. The question of the overall geometry, i.e. the aspect ratio, of DNA is revisited from the perspective of a geometrical...

  6. Financial Ratios and Perceived Household Financial Satisfaction

    Directory of Open Access Journals (Sweden)

    Scott Garrett

    2013-08-01

    Full Text Available This paper tests the relative strength of three objective measures of financial health (using the solvency, liquidity, and investment asset ratio in predicting a household’s subjective feeling of current financial satisfaction. Using a sample of 6,923 respondents in the 2008 Health and Retirement Study this paper presents evidence of two main findings: 1 the solvency ratio is most strongly associated with financial satisfaction levels based on a cross-sectional design and 2 changes in the investment asset ratio are most strongly associated with changes in financial satisfaction over time.

  7. Line intensity ratios of helium atom in an ionizing plasma

    International Nuclear Information System (INIS)

    Sasaki, Satoshi; Goto, Motoshi; Kato, Takako; Takamura, Shuichi

    1998-10-01

    Effective emission rate coefficients C em eff (λ), line intensity ratios, C em eff (λ 1 )/C em eff (λ 2 ), and S eff /C em eff (λ), with S eff the ionization rate coefficient, are obtained by the collisional radiative model for an ionizing plasma using new excitation and ionization rate coefficients. In the plasma with electron density n e > 10 4 cm -3 , C em eff (λ) for various lines are enlarged, since the normalized population densities for the metastable states, n(2 1,3 S)/n He , becomes large, and the excitation rate coefficients from 2 1,3 S, C 21,3S→i , are large compared to that from the ground state C 11S→i . In high n e plasma (n e > 10 12 cm -3 ), with frequent electron impacts on the excited heliums, n(i)/n He become constant to n e , which results in the decrease of C em eff (λ). Hot electrons and resonance scattering, which are often important for the experimental applications, are included in this model. A small amount of hot electrons (several percents) can enhance the line emission and ionization rates for low electron temperature plasma with T e (T e 1 S - n 1 P) and enlarges n 1 P and 2 1 S populations when the column density of helium gas n He x L exceeds 2x10 13 [cm -2 ]. (author)

  8. Transient Infrared Emission Spectroscopy

    Science.gov (United States)

    Jones, Roger W.; McClelland, John F.

    1989-12-01

    Transient Infrared Emission Spectroscopy (TIRES) is a new technique that reduces the occurrence of self-absorption in optically thick solid samples so that analytically useful emission spectra may be observed. Conventional emission spectroscopy, in which the sample is held at an elevated, uniform temperature, is practical only for optically thin samples. In thick samples the emission from deep layers of the material is partially absorbed by overlying layers.1 This self-absorption results in emission spectra from most optically thick samples that closely resemble black-body spectra. The characteristic discrete emission bands are severely truncated and altered in shape. TIRES bypasses this difficulty by using a laser to heat only an optically thin surface layer. The increased temperature of the layer is transient since the layer will rapidly cool and thicken by thermal diffusion; hence the emission collection must be correlated with the laser heating. TIRES may be done with both pulsed and cw lasers.2,3 When a pulsed laser is used, the spectrometer sampling must be synchronized with the laser pulsing so that only emission during and immediately after each laser pulse is observed.3 If a cw laser is used, the sample must move rapidly through the beam. The hot, transient layer is then in the beam track on the sample at and immediately behind the beam position, so the spectrometer field of view must be limited to this region near the beam position.2 How much self-absorption the observed emission suffers depends on how thick the heated layer has grown by thermal diffusion when the spectrometer samples the emission. Use of a pulsed laser synchronized with the spectrometer sampling readily permits reduction of the time available for heat diffusion to about 100 acs .3 When a cw laser is used, the heat-diffusion time is controlled by how small the spectrometer field of view is and by how rapidly the sample moves past within this field. Both a very small field of view and a

  9. Sheath structure transition controlled by secondary electron emission

    Science.gov (United States)

    Schweigert, I. V.; Langendorf, S. J.; Walker, M. L. R.; Keidar, M.

    2015-04-01

    In particle-in-cell Monte Carlo collision (PIC MCC) simulations and in an experiment we study sheath formation over an emissive floating Al2O3 plate in a direct current discharge plasma at argon gas pressure 10-4 Torr. The discharge glow is maintained by the beam electrons emitted from a negatively biased hot cathode. We observe three types of sheaths near the floating emissive plate and the transition between them is driven by changing the negative bias. The Debye sheath appears at lower voltages, when secondary electron emission is negligible. With increasing applied voltage, secondary electron emission switches on and a first transition to a new sheath type, beam electron emission (BEE), takes place. For the first time we find this specific regime of sheath operation near the floating emissive surface. In this regime, the potential drop over the plate sheath is about four times larger than the temperature of plasma electrons. The virtual cathode appears near the emissive plate and its modification helps to maintain the BEE regime within some voltage range. Further increase of the applied voltage U initiates the second smooth transition to the plasma electron emission sheath regime and the ratio Δφs/Te tends to unity with increasing U. The oscillatory behavior of the emissive sheath is analyzed in PIC MCC simulations. A plasmoid of slow electrons is formed near the plate and transported to the bulk plasma periodically with a frequency of about 25 kHz.

  10. Examining drivers of the emissions embodied in trade.

    Directory of Open Access Journals (Sweden)

    Leying Wu

    Full Text Available Emissions embodied in provincial trade (EEPT have important effects on provinces' responsibilities for carbon emission reductions. Based on a multi-regional input-output model, we calculated EEPT for China's 30 provinces in 2002, 2007 and 2010, and we attempted to determine the drivers of EEPT. The results showed that, during this period, the ratio of EEPT to production-based emissions increased over time, reaching 40.24% in 2010. In consideration of its important role in carbon emissions, we analyzed the factors attributable to EEPT through structure decomposition analysis. The decomposition results showed that final demand and carbon emission intensity were two major factors in EEPT, while the final demand in other provinces and the carbon emission intensity in the local province were major factors for Emissions embodied in provincial exports and the final demand in the local province and the carbon emission intensity in other provinces were major factors for Emissions embodied in provincial imports. Regarding the differences among the EEPT of different provinces, changes in the structure of trade were the primary reason.

  11. Electron field emission from boron doped microcrystalline diamond

    International Nuclear Information System (INIS)

    Roos, M.; Baranauskas, V.; Fontana, M.; Ceragioli, H.J.; Peterlevitz, A.C.; Mallik, K.; Degasperi, F.T.

    2007-01-01

    Field emission properties of hot filament chemical vapor deposited boron doped polycrystalline diamond have been studied. Doping level (N B ) of different samples has been varied by the B/C concentration in the gas feed during the growth process and doping saturation has been observed for high B/C ratios. Threshold field (E th ) for electron emission as function of B/C concentration has been measured, and the influences of grain boundaries, doping level and surface morphology on field emission properties have been investigated. Carrier transport through conductive grains and local emission properties of surface sites have been figured out to be two independent limiting effects in respect of field emission. Emitter current densities of 500 nA cm -2 were obtained using electric fields less than 8 V/μm

  12. Curious Sex Ratios and Cytoplasmic Genes

    Indian Academy of Sciences (India)

    instances of curious sex ratios exemplify an important principle: the fitness ..... markable transition - the whole means of sex determination has changed. No longer ... to the cytoplasmic symbiont is self-evident; the symbionts simply increase the.

  13. Asthma Medication Ratio Predicts Emergency Depart...

    Data.gov (United States)

    U.S. Department of Health & Human Services — According to findings reported in Asthma Medication Ratio Predicts Emergency Department Visits and Hospitalizations in Children with Asthma, published in Volume 3,...

  14. Anomalous Enantiomer Ratios in Meteoritic Sugar Derivatives

    Science.gov (United States)

    Cooper, G.; Sant, M.; Asiyo, C.

    2009-03-01

    The enantiomer (mirror-image) ratios of sugar acids in carbonaceous meteorites have been measured. D-enantiomer excesses are found in all acids measured thus far. This includes rare as well as common compounds.

  15. Recent development in isotope ratio mass spectrometry

    International Nuclear Information System (INIS)

    Platzner, I.

    1992-01-01

    Within the limited of this review the following topics will be briefly discussed: a) Accuracy, precision, internal relative standard deviation (RISD) and external relative standard deviation (RESD) of isotope ratio measurements. With advanced instrumentation and use of standard reference materials, high accuracy and RESD = 0.002% (or better) may be achieved; b) The advantages of modern automatic isotope ratio mass spectrometer are briefly described. Computer controlled operation and data acquisition, and multiple ion collection are the recent important improvement; c) The isotopic fractionation during the course of isotope ratio measurement is considered as a major source of errors in thermal ionization of metallic elements. The phenomenon in strontium, neodymium, uranium, lead and calcium and methods to correct the measured data are discussed; d) Applications of isotope ratio mass spectrometry in atomic weight determinations, the isotope dilution technique, isotope geology, and isotope effects in biological systems are described together with specific applications in various research and technology area. (author)

  16. Neutrophil Lymphocyte Ratio Predicts Postoperative Pain after ...

    African Journals Online (AJOL)

    2018-02-07

    Feb 7, 2018 ... between preoperatively measured neutrophil-lymphocyte ratio (NLR) – as an inflammation ... analgesic (tenoxicam – as the first drug of choice, paracetamol, tramadol, or pethidine) usage ... fracture fixation). Age, sex, type of ...

  17. Urine Albumin and Albumin/ Creatinine Ratio

    Science.gov (United States)

    ... it used? The urine albumin test or albumin/creatinine ratio (ACR) is used to screen people with chronic conditions, such as diabetes and high blood pressure ( hypertension ) that put them at an ...

  18. Temperature diagnostic line ratios of Fe XVII

    International Nuclear Information System (INIS)

    Raymond, J.C.; Smith, B.W.; Los Alamos National Lab., NM)

    1986-01-01

    Based on extensive calculations of the excitation rates of Fe XVII, four temperature-sensitive line ratios are investigated, paying special attention to the contribution of resonances to the excitation rates and to the contributions of dielectronic recombination satellites to the observed line intensities. The predictions are compared to FPCS observations of Puppis A and to Solar Maximum Mission (SMM) and SOLEX observations of the sun. Temperature-sensitive line ratios are also computed for emitting gas covering a broad temperature range. It is found that each ratio yields a differently weighted average for the temperature and that this accounts for some apparent discrepancies between the theoretical ratios and solar observations. The effects of this weighting on the Fe XVII temperature diagnostics and on the analogous Fe XXIV/Fe XXV satellite line temperature diagnostics are discussed. 27 references

  19. Ratio Analysis: Where Investments Meet Mathematics.

    Science.gov (United States)

    Barton, Susan D.; Woodbury, Denise

    2002-01-01

    Discusses ratio analysis by which investments may be evaluated. Requires the use of fundamental mathematics, problem solving, and a comparison of the mathematical results within the framework of industry. (Author/NB)

  20. Isotopic ratios in the solar system

    International Nuclear Information System (INIS)

    1985-01-01

    This colloquium is aimed at presentation of isotope ratio measurements in different objects of solar system and surrounding interstellar space and evaluation of what information on composition and structure of primitive solar nebula and on chemical evolution of interstellar space in this part of the galaxy can be deduced from it. Isotope ratio in solar system got from laboratory study of extraterrestrial materials is a subject of this colloquium. Then isotope ratio measured in solar wind, planets and comets. Measurements either are made in-situ by mass spectrometry of ions in solar wind or planetery atmosphere gases either are remote measurements of spectra emitted by giant planets and comets. At last, planetology and astrophysics implications are presented and reviewed. Consraints for solar system formation model can be deduced from isotope ratio measurement. Particularly, isotope anomalies are marks of the processes, which have influenced the primitive solar nebula contraction [fr

  1. From Fibonacci Sequence to the Golden Ratio

    Directory of Open Access Journals (Sweden)

    Alberto Fiorenza

    2013-01-01

    Full Text Available We consider the well-known characterization of the Golden ratio as limit of the ratio of consecutive terms of the Fibonacci sequence, and we give an explanation of this property in the framework of the Difference Equations Theory. We show that the Golden ratio coincides with this limit not because it is the root with maximum modulus and multiplicity of the characteristic polynomial, but, from a more general point of view, because it is the root with maximum modulus and multiplicity of a restricted set of roots, which in this special case coincides with the two roots of the characteristic polynomial. This new perspective is the heart of the characterization of the limit of ratio of consecutive terms of all linear homogeneous recurrences with constant coefficients, without any assumption on the roots of the characteristic polynomial, which may be, in particular, also complex and not real.

  2. Determining sex ratios of turtle hatchlings

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Previous status assessments of marine turtles have assumed that the natural sex ratio of a marine turtle population is 1:1 (e.g. Conant et al. 2009). However, this...

  3. Observations of Anomalous Microwave Emission from HII Regions

    Directory of Open Access Journals (Sweden)

    Clive Dickinson

    2013-01-01

    free-free emission from UCHII regions may be also be significant in some cases. The AME emissivity, defined as the ratio of the AME brightness to the 100 μm brightness, is comparable to the value observed in high-latitude diffuse cirrus in some regions, but is significantly lower in others. However, this value is dependent on the dust temperature. More data, both at high frequencies (>~5 GHz and high resolution (~1′ or better is required to disentangle the emission processes in such complex regions.

  4. Three-dimensional stereo by photometric ratios

    International Nuclear Information System (INIS)

    Wolff, L.B.; Angelopoulou, E.

    1994-01-01

    We present a methodology for corresponding a dense set of points on an object surface from photometric values for three-dimensional stereo computation of depth. The methodology utilizes multiple stereo pairs of images, with each stereo pair being taken of the identical scene but under different illumination. With just two stereo pairs of images taken under two different illumination conditions, a stereo pair of ratio images can be produced, one for the ratio of left-hand images and one for the ratio of right-hand images. We demonstrate how the photometric ratios composing these images can be used for accurate correspondence of object points. Object points having the same photometric ratio with respect to two different illumination conditions constitute a well-defined equivalence class of physical constraints defined by local surface orientation relative to illumination conditions. We formally show that for diffuse reflection the photometric ratio is invariant to varying camera characteristics, surface albedo, and viewpoint and that therefore the same photometric ratio in both images of a stereo pair implies the same equivalence class of physical constraints. The correspondence of photometric ratios along epipolar lines in a stereo pair of images under different illumination conditions is a correspondence of equivalent physical constraints, and the determination of depth from stereo can be performed. Whereas illumination planning is required, our photometric-based stereo methodology does not require knowledge of illumination conditions in the actual computation of three-dimensional depth and is applicable to perspective views. This technique extends the stereo determination of three-dimensional depth to smooth featureless surfaces without the use of precisely calibrated lighting. We demonstrate experimental depth maps from a dense set of points on smooth objects of known ground-truth shape, determined to within 1% depth accuracy

  5. The Laplace Likelihood Ratio Test for Heteroscedasticity

    Directory of Open Access Journals (Sweden)

    J. Martin van Zyl

    2011-01-01

    Full Text Available It is shown that the likelihood ratio test for heteroscedasticity, assuming the Laplace distribution, gives good results for Gaussian and fat-tailed data. The likelihood ratio test, assuming normality, is very sensitive to any deviation from normality, especially when the observations are from a distribution with fat tails. Such a likelihood test can also be used as a robust test for a constant variance in residuals or a time series if the data is partitioned into groups.

  6. A note on trader Sharpe Ratios.

    Science.gov (United States)

    Coates, John M; Page, Lionel

    2009-11-25

    Traders in the financial world are assessed by the amount of money they make and, increasingly, by the amount of money they make per unit of risk taken, a measure known as the Sharpe Ratio. Little is known about the average Sharpe Ratio among traders, but the Efficient Market Hypothesis suggests that traders, like asset managers, should not outperform the broad market. Here we report the findings of a study conducted in the City of London which shows that a population of experienced traders attain Sharpe Ratios significantly higher than the broad market. To explain this anomaly we examine a surrogate marker of prenatal androgen exposure, the second-to-fourth finger length ratio (2D:4D), which has previously been identified as predicting a trader's long term profitability. We find that it predicts the amount of risk taken by traders but not their Sharpe Ratios. We do, however, find that the traders' Sharpe Ratios increase markedly with the number of years they have traded, a result suggesting that learning plays a role in increasing the returns of traders. Our findings present anomalous data for the Efficient Markets Hypothesis.

  7. A note on trader Sharpe Ratios.

    Directory of Open Access Journals (Sweden)

    John M Coates

    Full Text Available Traders in the financial world are assessed by the amount of money they make and, increasingly, by the amount of money they make per unit of risk taken, a measure known as the Sharpe Ratio. Little is known about the average Sharpe Ratio among traders, but the Efficient Market Hypothesis suggests that traders, like asset managers, should not outperform the broad market. Here we report the findings of a study conducted in the City of London which shows that a population of experienced traders attain Sharpe Ratios significantly higher than the broad market. To explain this anomaly we examine a surrogate marker of prenatal androgen exposure, the second-to-fourth finger length ratio (2D:4D, which has previously been identified as predicting a trader's long term profitability. We find that it predicts the amount of risk taken by traders but not their Sharpe Ratios. We do, however, find that the traders' Sharpe Ratios increase markedly with the number of years they have traded, a result suggesting that learning plays a role in increasing the returns of traders. Our findings present anomalous data for the Efficient Markets Hypothesis.

  8. INFLUENCE OF SCALE RATIO, ASPECT RATIO, AND PLANFORM ON THE PERFORMANCE OF SUPERCAVITATING HYDROFOILS.

    Science.gov (United States)

    performance of supercavitating hydrofoils. No appreciable scale effect was found for scale ratios up to 3 in the fully-cavitating flow region. The...overall performance of the hydrofoil by increasing the aspect ratio above 3, and (2) moderate taper ratio seems to be advantageous in view of the overall performance of supercavitating hydrofoils. (Author)

  9. N2O and NO2 Emissions from Heavy-Duty Diesel Trucks with Advanced Emission Controls

    Science.gov (United States)

    Preble, C.; Harley, R.; Kirchstetter, T.

    2014-12-01

    Diesel engines are the largest source of nitrogen oxides (NOx) emissions nationally, and also a major contributor to the black carbon (BC) fraction of fine particulate matter (PM). Recently, diesel particle filter (DPF) and selective catalytic reduction (SCR) emission control systems that target exhaust PM and NOx have become standard equipment on new heavy-duty diesel trucks. However, the deliberate catalytic oxidation of engine-out nitric oxide (NO) to nitrogen dioxide (NO2) in continuously regenerating DPFs leads to increased tailpipe emission of NO2. This is of potential concern due to the toxicity of NO2 and the resulting increases in atmospheric formation of other air pollutants such as ozone, nitric acid, and fine PM. While use of SCR reduces emissions of both NO and NO2, it may lead to increased emissions of nitrous oxide (N2O), a potent greenhouse gas. Here we report results from on-road measurements of heavy-duty diesel truck emissions conducted at the Port of Oakland and the Caldecott Tunnel in the San Francisco Bay Area. Emission factors (g pollutant per kg of diesel) were linked via recorded license plates to individual truck attributes, including engine model year and installed emission control equipment. Between 2009 and 2013, the fraction of DPF-equipped trucks at the Port of Oakland increased from 2 to 99%, and median engine age decreased from 11 to 6 years. Over the same period, fleet-average emission factors for black carbon and NOx decreased by 76 ± 22% and 53 ± 8%, respectively. However, direct emissions of NO2 increased, and consequently the NO2/NOx emission ratio increased from 0.03 ± 0.02 to 0.18 ± 0.03. Older trucks retrofitted with DPFs emitted approximately 3.5 times more NO2 than newer trucks equipped with both DPF and SCR. Preliminary data from summer 2014 measurements at the Caldecott Tunnel suggest that some older trucks have negative emission factors for N2O, and that for newer trucks, N2O emission factors have changed sign and

  10. Comparison of emissions from on-road sources using a mobile laboratory under various driving and operational sampling modes

    Directory of Open Access Journals (Sweden)

    M. Zavala

    2009-01-01

    Full Text Available Mobile sources produce a significant fraction of the total anthropogenic emissions burden in large cities and have harmful effects on air quality at multiple spatial scales. Mobile emissions are intrinsically difficult to estimate due to the large number of parameters affecting the emissions variability within and across vehicles types. The MCMA-2003 Campaign in Mexico City has showed the utility of using a mobile laboratory to sample and characterize specific classes of motor vehicles to better quantify their emissions characteristics as a function of their driving cycles. The technique clearly identifies "high emitter" vehicles via individual exhaust plumes, and also provides fleet average emission rates. We have applied this technique to Mexicali during the Border Ozone Reduction and Air Quality Improvement Program (BORAQIP for the Mexicali-Imperial Valley in 2005. We analyze the variability of measured emission ratios for emitted NOx, CO, specific VOCs, NH3, and some primary fine particle components and properties by deploying a mobile laboratory in roadside stationary sampling, chase and fleet average operational sampling modes. The measurements reflect various driving modes characteristic of the urban fleets. The observed variability for all measured gases and particle emission ratios is greater for the chase and roadside stationary sampling than for fleet average measurements. The fleet average sampling mode captured the effects of traffic conditions on the measured on-road emission ratios, allowing the use of fuel-based emission ratios to assess the validity of traditional "bottom-up" emissions inventories. Using the measured on-road emission ratios, we estimate CO and NOx mobile emissions of 175±62 and 10.4±1.3 metric tons/day, respectively, for the gasoline vehicle fleet in Mexicali. Comparisons with similar on-road emissions data from Mexico City indicated that fleet average NO emission ratios were

  11. Economical benzene emission reduction

    International Nuclear Information System (INIS)

    Schuetz, R.

    1999-01-01

    Benzene has been classified as a toxic compound under the Canadian Environmental Protection Act. This has prompted the Alberta Energy and Utilities Board (AEUB) to introduce specific reporting and monitoring guidelines for the oil and gas industry regarding excessive benzene emissions. Glycol dehydration units have been determined to be the major single source of benzene emissions causing air and soil pollution. DualTank Corp. has designed a condensation and storage tank unit to enhance emission reduction, odour elimination and liquid recovery from dehydration units. Their newly designed combined tank unit consists of a large, uninsulated surface area for cooling, and an excessive internal volume for increased retention time. The first prototype was installed in December 1998 at an Enerplus Resources Site. The system provides excellent benzene emission reduction and the elimination of odours and visual plumes. Effective January 1, 1999, the petroleum and natural gas industry must either clean up excessive emissions voluntarily or face government imposed regulations, facility shutdowns and/or fines. 1 fig

  12. Comparison of CO2 Emissions Data for 30 Cities from Different Sources

    Science.gov (United States)

    Nakagawa, Y.; Koide, D.; Ito, A.; Saito, M.; Hirata, R.

    2017-12-01

    Many sources suggest that cities account for a large proportion of global anthropogenic greenhouse gas emissions. Therefore, in search for the best ways to reduce total anthropogenic greenhouse gas emissions, a focus on the city emission is crucial. In this study, we collected CO2 emissions data in 30 cities during 1990-2015 and evaluated the degree of variance between data sources. The CO2 emissions data were obtained from academic papers, municipal reports, and high-resolution emissions maps (CIDIACv2016, EDGARv4.2, ODIACv2016, and FFDASv2.0). To extract urban CO2 emissions from the high-resolution emissions maps, urban fraction ranging from 0 to 1 was calculated for each 1×1 degree grid cell using the global land cover data (SYNMAP). Total CO2 emissions from the grid cells in which urban fraction occupies greater than or equal to 0.9 were regarded as urban CO2 emissions. The estimated CO2 emissions varied greatly depending on the information sources, even in the same year. There was a large difference between CO2 emissions collected from academic papers, municipal reports, and those extracted from high-resolution emissions maps. One reason is that they use different city boundaries. That is, the city proper (i.e. the political city boundary) is often defined as the city boundary in academic papers and municipal reports, whereas the urban area is used in the high-resolution emissions maps. Furthermore, there was a large variation in CO2 emissions collected from academic papers and municipal reports. These differences may be due to the difference in the assumptions such as allocation ratio of CO2 emissions to producers and consumers. In general, the consumption-based assignment of emissions gives higher estimates of urban CO2 emission in comparison with production-based assignment. Furthermore, there was also a large variation in CO2 emissions extracted from high-resolution emissions maps. This difference would be attributable to differences in information used

  13. On the K-term and dispersion ratios of semi-regular variables

    International Nuclear Information System (INIS)

    Aslan, Z.

    1981-01-01

    Optical velocities of semi-regular (SR) and irregular (Lb) variables are analysed for a K-term. There is evidence for a dependence upon stellar period. Absorption lines in shorter period non-emission SR variables are blue-shifted relative to the centre-of-mass velocity by about 6 +- 3 km s -1 . Emission-line SR variables give a non-negative absorption K-term and Lb variables give no K-terms other than zero. Comparison is made with the K-terms implied by the OH velocity pattern in long-period variables. Dispersion ratios are also calculated. (author)

  14. Tamanu oil. An alternative fuel for variable compression ratio engine

    Energy Technology Data Exchange (ETDEWEB)

    Raj, Mohan T. [SASTRA Univ., Thanjavur, Tamilnadu (India). Dept. of Mechanical Engineering; Kandasamy, Murugumohan Kumar K. [Pavendar Bharathidasan College of Engineering and Technology, Trichy, Tamilnadu (India). Dept. of Mechanical Engineering

    2012-11-01

    Biodiesel can be produced from vegetable oils and also from waste fats. Biodiesel is a monoalkyl- ester of long chain fatty acids derived from renewable feedstock such as vegetable oils by transesterification process. The esterified cotton seed oil, pungam oil, rice bran oil, and tamanu oil are chosen as the alternative fuels. Among these oils, tamanu oil is considered for the first time as an alternative fuel. An experiment is conducted to obtain the operating characteristics of the variable compression ratio (VCR) engine run by chosen esterified oils, and the results are compared with esterified tamanu oil. From the comparison of results, it is inferred that the engine performance is improved with significant reduction in emissions for the chosen oils without any engine modification. The effective compression ratio can be fixed based on the experimental results obtained in the engine since the findings of the present research work infer that the biodiesel obtained from tamanu oil is a promising alternative fuel for direct-injection four-stroke VCR engine. (orig.)

  15. Changes in monoterpene mixing ratios during summer storms in rural New Hampshire (USA

    Directory of Open Access Journals (Sweden)

    K. B. Haase

    2011-11-01

    Full Text Available Monoterpenes are an important class of biogenic hydrocarbons that influence ambient air quality and are a principle source of secondary organic aerosol (SOA. Emitted from vegetation, monoterpenes are a product of photosynthesis and act as a response to a variety of environmental factors. Most parameterizations of monoterpene emissions are based on clear weather models that do not take into account episodic conditions that can drastically change production and release rates into the atmosphere. Here, the monoterpene dataset from the rural Thompson Farm measurement site in Durham, New Hampshire is examined in the context of a set of known severe storm events. While some storm systems had a negligible influence on ambient monoterpene mixing ratios, the average storm event increased mixing ratios by 0.59 ± 0.21 ppbv, a factor of 93% above pre-storm levels. In some events, mixing ratios reached the 10's of ppbv range and persisted overnight. These mixing ratios correspond to increases in the monoterpene emission rate, ranging from 120 to 1240 g km−2 h−1 compared to an estimated clear weather rate of 116 to 193 g km−2 h−1. Considering the regularity of storm events over most forested areas, this could be an important factor to consider when modeling global monoterpene emissions and their resulting influence on the formation of organic aerosols.

  16. Changes in monoterpene mixing ratios during summer storms in rural New Hampshire (USA)

    Science.gov (United States)

    Haase, K.B.; Jordan, C.; Mentis, E.; Cottrell, L.; Mayne, H.R.; Talbot, R.; Sive, B.C.

    2011-01-01

    Monoterpenes are an important class of biogenic hydrocarbons that influence ambient air quality and are a principle source of secondary organic aerosol (SOA). Emitted from vegetation, monoterpenes are a product of photosynthesis and act as a response to a variety of environmental factors. Most parameterizations of monoterpene emissions are based on clear weather models that do not take into account episodic conditions that can drastically change production and release rates into the atmosphere. Here, the ongoing monoterpene dataset from the rural Thompson Farm measurement site in Durham, New Hampshire is examined in the context of a set of known severe storm events. While some storm systems had a negligible influence on ambient monoterpene mixing ratios, the average storm event increased mixing ratios by 0.59 ?? 0.21 ppbv, a factor of 93 % above pre-storm levels. In some events, mixing ratios reached the 10's of ppbv range and persisted overnight. These mixing ratios correspond to increases in the monoterpene emission rate, ranging from 120 to 1240 g km-2 h -1 compared to an estimated clear weather rate of 116 to 193 g km-2 h-1. Considering the regularity of storm events over most forested areas, this could be an important factor to consider when modeling global monoterpene emissions and their resulting influence on the formation of organic aerosols. ?? 2011 Author(s).

  17. High resolution of black carbon and organic carbon emissions in the Pearl River Delta region, China.

    Science.gov (United States)

    Zheng, Junyu; He, Min; Shen, Xingling; Yin, Shasha; Yuan, Zibing

    2012-11-01

    A high-resolution regional black carbon (BC) and organic carbon (OC) emission inventory for the year 2009 was developed for the Pearl River Delta (PRD) region, China, based on the collected activity data and the latest emission factors. PM(2.5), BC and OC emissions were estimated to be 303 kt, 39 kt and 31 kt, respectively. Industrial processes were major contributing sources to PM(2.5) emissions. BC emissions were mainly from mobile sources, accounting for 65.0%, while 34.1% of OC emissions were from residential combustion. The primary OC/BC ratios for individual cities in the PRD region were dependent on the levels of economic development due to differences in source characteristics, with high ratios in the less developed cities and low ratios in the central and southern developed areas. The preliminary temporal profiles were established, showing the highest OC emissions in winter and relatively constant BC emissions throughout the year. The emissions were spatially allocated into grid cells with a resolution of 3 km × 3 km. Large amounts of BC emissions were distributed over the central-southern PRD city clusters, while OC emissions exhibited a relatively even spatial distribution due to the significant biomass burning emissions from the outlying area of the PRD region. Uncertainties in carbonaceous aerosol emissions were usually higher than in other primary pollutants like SO(2), NO(x), and PM(10). One of the key uncertainty sources was the emission factor, due to the absence of direct measurements of BC and OC emission rates. Copyright © 2012 Elsevier B.V. All rights reserved.

  18. Sex ratios at birth after induced abortion.

    Science.gov (United States)

    Urquia, Marcelo L; Moineddin, Rahim; Jha, Prabhat; O'Campo, Patricia J; McKenzie, Kwame; Glazier, Richard H; Henry, David A; Ray, Joel G

    2016-06-14

    Skewed male:female ratios at birth have been observed among certain immigrant groups. Data on abortion practices that might help to explain these findings are lacking. We examined 1 220 933 births to women with up to 3 consecutive singleton live births between 1993 and 2012 in Ontario. Records of live births, and induced and spontaneous abortions were linked to Canadian immigration records. We determined associations of male:female infant ratios with maternal birthplace, sex of the previous living sibling(s) and prior spontaneous or induced abortions. Male:female infant ratios did not appreciably depart from the normal range among Canadian-born women and most women born outside of Canada, irrespective of the sex of previous children or the characteristics of prior abortions. However, among infants of women who immigrated from India and had previously given birth to 2 girls, the overall male:female ratio was 1.96 (95% confidence interval [CI] 1.75-2.21) for the third live birth. The male:female infant ratio after 2 girls was 1.77 (95% CI 1.26-2.47) times higher if the current birth was preceded by 1 induced abortion, 2.38 (95% CI 1.44-3.94) times higher if preceded by 2 or more induced abortions and 3.88 (95% CI 2.02-7.50) times higher if the induced abortion was performed at 15 weeks or more gestation relative to no preceding abortion. Spontaneous abortions were not associated with male-biased sex ratios in subsequent births. High male:female ratios observed among infants born to women who immigrated from India are associated with induced abortions, especially in the second trimester of pregnancy. © 2016 Canadian Medical Association or its licensors.

  19. NMHC emissions from Asia: sources and transport

    Science.gov (United States)

    Shirai, T.; Blake, D. R.; Barletta, B.; Meinardi, S.; Rowland, F. S.; Chan, J. C.; Takegawa, N.; Kondo, Y.; Koike, M.; Kita, K.; Takigawa, M.; Kawakami, S.; Ogawa, T.

    2002-12-01

    Recent rapid industrialization and economic growth in Asia changed the industrial structure, land use, and people's lifestyle resulting in a dramatic change in the amount and composition of the gas emissions from Asia. Because emissions can be transported very rapidly once convected to the free troposphere, Asian emissions can affect both local and regional air quality and climate. To access the impact of changing emission from Asia, an airborne observation campaign PEACE (the Pacific Exploration of Asian Continental Emission) phase-A and B were conducted in January and April - May 2002, respectively, sponsored by NASDA (National Space Development Agency of Japan). The concentrations of NMHCs (nonmethanehydrocarbons) and halocarbons were obtained by whole air sampling and subsequent gas chromatography analyses in the laboratory. Quantified onboard the aircraft were CO, CO2, O3, NO, NO2, NOy, H2O, SO2, aerosols, and condensation nuclei. The experiment was conducted in the vicinity of Japan and PEACE-A and B represent the local winter and spring weather conditions. The trace gas distributions in the lower troposphere were often influenced by local pollution (i.e. from Japan, Korea) while those of the long-range transport (i.e. from Europe) were occasionally seen in the upper troposphere. This is confirmed by the airmass age estimation using the ratios of short-lived gases (i.e. C2H4) vs. more stable compounds (i.e. CO). Emissions from China were distinguished using data obtained from ground-based sampling and measurements. Transport from China was seen both in the lower troposphere and upper troposphere. Some case studies on source identification will be discussed.

  20. Transportation Emissions: some basics

    DEFF Research Database (Denmark)

    Kontovas, Christos A.; Psaraftis, Harilaos N.

    2016-01-01

    transportation and especially carbon dioxide emissions are at the center stage of discussion by the world community through various international treaties, such as the Kyoto Protocol. The transportation sector also emits non-CO2 pollutants that have important effects on air quality, climate, and public health......Transportation is the backbone of international trade and a key engine driving globalization. However, there is growing concern that the Earth’s atmospheric composition is being altered by human activities, including transportation, which can lead to climate change. Air pollution from....... The main purpose of this chapter is to introduce some basic concepts that are relevant in the quest of green transportation logistics. First, we present the basics of estimating emissions from transportation activities, the current statistics and future trends, as well as the total impact of air emissions...

  1. Practical acoustic emission testing

    CERN Document Server

    2016-01-01

    This book is intended for non-destructive testing (NDT) technicians who want to learn practical acoustic emission testing based on level 1 of ISO 9712 (Non-destructive testing – Qualification and certification of personnel) criteria. The essential aspects of ISO/DIS 18436-6 (Condition monitoring and diagnostics of machines – Requirements for training and certification of personnel, Part 6: Acoustic Emission) are explained, and readers can deepen their understanding with the help of practice exercises. This work presents the guiding principles of acoustic emission measurement, signal processing, algorithms for source location, measurement devices, applicability of testing methods, and measurement cases to support not only researchers in this field but also and especially NDT technicians.

  2. Instantaneous wave emission model

    International Nuclear Information System (INIS)

    Kruer, W.L.

    1970-12-01

    A useful treatment of electrostatic wave emission by fast particles in a plasma is given. First, the potential due to a fast particle is expressed as a simple integration over the particle orbit; several interesting results readily follow. The potential in the wake of an accelerating particle is shown to be essentially that produced through local excitation of the plasma by the particle free-streaming about its instantaneous orbit. Application is made to one dimension, and it is shown that the wave emission and adsorption synchronize to the instantaneous velocity distribution function. Guided by these calculations, we then formulate a test particle model for computing the instantaneous wave emission by fast particles in a Vlasov plasma. This model lends itself to physical interpretation and provides a direct approach to many problems. By adopting a Fokker-Planck description for the particle dynamics, we calculate the broadening of the wave-particle resonance due to velocity diffusion and drag

  3. Tomography by positrons emission

    International Nuclear Information System (INIS)

    Mosconi, Sergio L.

    1999-01-01

    The tomography by positrons emission is a technology that allows to measure the concentration of positrons emission in a tri dimensional body through external measurements. Among the isotope emissions have carbon isotopes are ( 11 C), of the oxygen ( 15 O), of the nitrogen ( 13 N) that are three the element that constitute the base of the organic chemistry. Theses have on of the PET's most important advantages, since many biological interesting organic molecules can be tracer with these isotopes for the metabolism studies 'in vivo' through PET, without using organic tracers that modify the metabolism. The mentioned isotopes, also possess the characteristic of having short lifetime, that constitute on of PET's advantages from the dosimetric point of view. Among 11 C, 15 O, and 13 N, other isotopes that can be obtained of a generator as the 68 Ga and 82 Rb

  4. Carbon emissions control strategies

    International Nuclear Information System (INIS)

    Chandler, W.U.

    1990-01-01

    This study was undertaken to address a fundamental issue: the cost of slowing climate change. Experts in eight nations were asked to evaluate, using the best economic models available, the prospects for reducing fossil fuel-based carbon emissions in their respective nations. The nations selected as case studies include: the Soviet Union, Poland, the United States, Japan, Hungary, France, the United Kingdom, and Canada. As important contributors to the greenhouse effect, these industrialized nations must find ways to substantially reduce their emissions. This is especially critical given that developing nations' emissions are expected to rise in the coming decades in the search for economic development. Ten papers have been processed separately for inclusion in the appropriate data bases

  5. Acoustic Emission Stethoscope - Measurements with Acoustic Emission on Wind Turbines

    Energy Technology Data Exchange (ETDEWEB)

    Krystof Kryniski [AaF Infrastructure, Stockholm (Sweden)

    2013-02-15

    A remote ultrasonic stethoscope, designed on mobile devices to help a maintenance team in diagnosing drive train problems, has been demonstrated. By implementing an acoustic emission technology, the operating conditions of wind turbines have been assessed by trending techniques and ultrasonic acoustic emission converted into audible sound. The new approach has been developed and tested and compared to other monitoring techniques. Acoustic emission has generally been shown to provide a number of advantages over vibration and shock pulse methods because the system is operating in a substantially higher frequency range (100 kHz) and therefore it is more immune to operation of surrounding machines and components. Quick attenuation of ultrasonic propagation waves in the drive-train structure helps to pin-point the origin of any fault as the signals are sharper and more pronounced. Further, with the intensity measurements a direction of the source of ultrasonic energy can be identified. Using a high frequency thus makes the method suitable for measuring local effects and to determine local defects since the disturbing signals from other parts are damped. Recently developed programmable sensors capable of processing signals onboard, producing quality outputs with extremely low noise-to-signal ratio, have been used. It is discussed how the new approach can lower the cost of a wind-turbine monitoring system, while at the same time making it simple and more reliable, see Appendix A. The method has been tested on rotating parts of wind-turbines, including traditionally difficult areas such as low speed main bearings and planetary gearboxes. The method developed in the project was designed to see physical processes such as friction, impacts and metal removal, occurring when machinery degrades, can be detected and notified with the developed notification system. Apart from reporting the status and displaying the changes of the pre-defined parameters or symptoms, the system has

  6. Serial binary interval ratios improve rhythm reproduction.

    Science.gov (United States)

    Wu, Xiang; Westanmo, Anders; Zhou, Liang; Pan, Junhao

    2013-01-01

    Musical rhythm perception is a natural human ability that involves complex cognitive processes. Rhythm refers to the organization of events in time, and musical rhythms have an underlying hierarchical metrical structure. The metrical structure induces the feeling of a beat and the extent to which a rhythm induces the feeling of a beat is referred to as its metrical strength. Binary ratios are the most frequent interval ratio in musical rhythms. Rhythms with hierarchical binary ratios are better discriminated and reproduced than rhythms with hierarchical non-binary ratios. However, it remains unclear whether a superiority of serial binary over non-binary ratios in rhythm perception and reproduction exists. In addition, how different types of serial ratios influence the metrical strength of rhythms remains to be elucidated. The present study investigated serial binary vs. non-binary ratios in a reproduction task. Rhythms formed with exclusively binary (1:2:4:8), non-binary integer (1:3:5:6), and non-integer (1:2.3:5.3:6.4) ratios were examined within a constant meter. The results showed that the 1:2:4:8 rhythm type was more accurately reproduced than the 1:3:5:6 and 1:2.3:5.3:6.4 rhythm types, and the 1:2.3:5.3:6.4 rhythm type was more accurately reproduced than the 1:3:5:6 rhythm type. Further analyses showed that reproduction performance was better predicted by the distribution pattern of event occurrences within an inter-beat interval, than by the coincidence of events with beats, or the magnitude and complexity of interval ratios. Whereas rhythm theories and empirical data emphasize the role of the coincidence of events with beats in determining metrical strength and predicting rhythm performance, the present results suggest that rhythm processing may be better understood when the distribution pattern of event occurrences is taken into account. These results provide new insights into the mechanisms underlining musical rhythm perception.

  7. Serial binary interval ratios improve rhythm reproduction

    Directory of Open Access Journals (Sweden)

    Xiang eWu

    2013-08-01

    Full Text Available Musical rhythm perception is a natural human ability that involves complex cognitive processes. Rhythm refers to the organization of events in time, and musical rhythms have an underlying hierarchical metrical structure. The metrical structure induces the feeling of a beat and the extent to which a rhythm induces the feeling of a beat is referred to as its metrical strength. Binary ratios are the most frequent interval ratio in musical rhythms. Rhythms with hierarchical binary ratios are better discriminated and reproduced than rhythms with hierarchical non-binary ratios. However, it remains unclear whether a superiority of serial binary over non-binary ratios in rhythm perception and reproduction exists. In addition, how different types of serial ratios influence the metrical strength of rhythms remains to be elucidated. The present study investigated serial binary vs. non-binary ratios in a reproduction task. Rhythms formed with exclusively binary (1:2:4:8, non-binary integer (1:3:5:6, and non-integer (1:2.3:5.3:6.4 ratios were examined within a constant meter. The results showed that the 1:2:4:8 rhythm type was more accurately reproduced than the 1:3:5:6 and 1:2.3:5.3:6.4 rhythm types, and the 1:2.3:5.3:6.4 rhythm type was more accurately reproduced than the 1:3:5:6 rhythm type. Further analyses showed that reproduction performance was better predicted by the distribution pattern of event occurrences within an inter-beat interval, than by the coincidence of events with beats, or the magnitude and complexity of interval ratios. Whereas rhythm theories and empirical data emphasize the role of the coincidence of events with beats in determining metrical strength and predicting rhythm performance, the present results suggest that rhythm processing may be better understood when the distribution pattern of event occurrences is taken into account. These results provide new insights into the mechanisms underlining musical rhythm perception.

  8. Novel bacterial ratio for predicting fecal age

    Energy Technology Data Exchange (ETDEWEB)

    Nieman, J.; Brion, G.M. [Univ. of Kentucky, Dept. of Civil Engineering, Lexington, Kentucky (United States)]. E-mail: gbrion@engr.uky.edu

    2002-06-15

    This study presents an extension of ongoing research into the utility of the ratio of bacterial colonies isolated on membrane filters during the total coliform test using m-Endo broth media for the prediction of fecal age. Analysis of the relative shifts in concentrations of indicator bacterial populations in Kentucky River water quality data collected from the inlet of a local water treatment plant showed a correlation between raw concentrations of atypical colonies (AC) and total coliform colonies (TC) formed on m-Endo membrane filter tests, and fecal age. Visual analysis of plant treatment records showed that low values of the AC/TC ratio were related to periods of high flow, when runoff added fresh fecal material to the river. A more detailed analysis of 2 years of Kentucky River water quality data showed the average AC/TC ratio during months with high river flow (rain) to be 3.4, rising to an average of 27.6 during months with low flow. The average AC/TC ratio during high flow months compared to that found in other studies for raw human sewage (3.9) and the ratio increased to values associated with animal impacted urban runoff (18.9) during low flow months. (author)

  9. Mixing ratio sensor for alcohol mixed fuel

    Energy Technology Data Exchange (ETDEWEB)

    Miyata, Shigeru; Matsubara, Yoshihiro

    1987-08-24

    In order to improve the combustion efficiency of an internal combustion engine using gasoline-alcohol mixed fuel and to reduce harmful substance in its exhaust gas, it is necessary to control strictly the air-fuel ratio to be supplied and the ignition timing. In order to detect the mixing ratio of the mixed fuel, a mixing ratio sensor has so far been proposed to detect the above mixing ratio by casting a ray of light to the mixed fuel and utilizing a change of critical angle associated with the change of the composition of the fluid of the mixed fuel. However, because of the arrangement of its transparent substance in the fuel passage with the sealing material in between, this sensor invited the leakage of the fluid due to deterioration of the sealing material, etc. and its cost became high because of too many parts to be assembled. In view of the above, in order to reduce the number of parts, to lower the cost of parts and the assembling cost and to secure no fluid leakage from the fuel passage, this invention formed the above fuel passage and the above transparent substance both concerning the above mixing ratio sensor in an integrated manner using light transmitting resin. (3 figs)

  10. Novel bacterial ratio for predicting fecal age

    International Nuclear Information System (INIS)

    Nieman, J.; Brion, G.M.

    2002-01-01

    This study presents an extension of ongoing research into the utility of the ratio of bacterial colonies isolated on membrane filters during the total coliform test using m-Endo broth media for the prediction of fecal age. Analysis of the relative shifts in concentrations of indicator bacterial populations in Kentucky River water quality data collected from the inlet of a local water treatment plant showed a correlation between raw concentrations of atypical colonies (AC) and total coliform colonies (TC) formed on m-Endo membrane filter tests, and fecal age. Visual analysis of plant treatment records showed that low values of the AC/TC ratio were related to periods of high flow, when runoff added fresh fecal material to the river. A more detailed analysis of 2 years of Kentucky River water quality data showed the average AC/TC ratio during months with high river flow (rain) to be 3.4, rising to an average of 27.6 during months with low flow. The average AC/TC ratio during high flow months compared to that found in other studies for raw human sewage (3.9) and the ratio increased to values associated with animal impacted urban runoff (18.9) during low flow months. (author)

  11. Golden ratio beauty as scientific function

    Directory of Open Access Journals (Sweden)

    Scott A. Olsen

    2018-01-01

    Full Text Available Normally when one is considering the golden ratio in the history of ideas, one is often looking at it as an aesthetic principle – usually associated with Greek art, sculpture and mathematics. However, in recent years the prevalence of the golden ratio within a broad range of scientific disciplines has brought its role in the perfection of science to the forefront. I would like to collapse these two areas by proposing a somewhat novel way of looking at the aesthetics of the golden ratio: its pervasive expression in scientific form and function is the basis of the aesthetics in the world. Therefore, science contains the same mathematical beauty as found in artistic expression. The golden ratio guides the Chaos Border of Kolmogorov, Arnold, and Moser (KAM theorem and it can be found hidden in all elementary particles, and even in the proportions of dark matter and energy relative to visible matter and energy. It is evident in the structure and growth functions of plants and animals and it can be found in the physiological functions of humans. It now appears that without the golden ratio, we would not have the form or function of the proton, cell, athlete, horse, species, planet, solar system or galaxy.

  12. Field emission electronics

    CERN Document Server

    Egorov, Nikolay

    2017-01-01

    This book is dedicated to field emission electronics, a promising field at the interface between “classic” vacuum electronics and nanotechnology. In addition to theoretical models, it includes detailed descriptions of experimental and research techniques and production technologies for different types of field emitters based on various construction principles. It particularly focuses on research into and production of field cathodes and electron guns using recently developed nanomaterials and carbon nanotubes. Further, it discusses the applications of field emission cathodes in new technologies such as light sources, flat screens, microwave and X-ray devices.

  13. Positron emission tomography

    International Nuclear Information System (INIS)

    Wienhard, K.; Heiss, W.D.

    1984-01-01

    The principles and selected clinical applications of positron emission tomography are described. In this technique a chemical compound is labeled with a positron emitting isotope and its biochemical pathway is traced by coincidence detection of the two annihilation photons. The application of the techniques of computed tomography allows to reconstruct the spatial distribution of the radioactivity within a subject. The 18 F-deoxyglucose method for quantitative measurement of local glucose metabolism is discussed in order to illustrate the possibilities of positron emission tomography to record physiological processes in vivo. (orig.) [de

  14. Positron emission tomography

    International Nuclear Information System (INIS)

    Paans, A.M.J.

    1981-01-01

    Positron emitting radiopharmaceuticals have special applications in in-vivo studies of biochemical processes. The combination of a cyclotron for the production of radionuclides and a positron emission tomograph for the registration of the distribution of radioactivity in the body enables the measurement of local radioactivity concentration in tissues, and opens up new possibilities in the diagnosis and examination of abnormalities in the metabolism. The principles and procedures of positron emission tomography are described and the necessary apparatus considered, with emphasis on the positron camera. The first clinical applications using 55 Co bloemycine for tumor detection are presented. (C.F.)

  15. Secondary ion emission

    International Nuclear Information System (INIS)

    Krohn, V.E.

    1976-01-01

    The Saha-Langmuir equation that describes the equilibrium emission process, surface ionization, has also been used to describe ion yields observed in the non-equilibrium emission process, sputtering. In describing sputtering, it is probably best to include the potential due to an image charge in the expression for negative as well as positive ion yield and to treat the work function and the temperature as parameters having limited physical significance. Arguments are presented to suggest that sputtered material is not emitted from a plasma. (Auth.)

  16. The morphology of the Anomalous Microwave Emission in the Planck 2015 data release

    Energy Technology Data Exchange (ETDEWEB)

    Hausegger, Sebastian von; Liu, Hao, E-mail: s.vonhausegger@nbi.dk, E-mail: liuhao@nbi.dk [The Niels Bohr Institute and Discovery Center, Blegdamsvej 17, 2100 Copenhagen Ø (Denmark)

    2015-08-01

    We calculate weighted mosaic correlations between the recently published Planck 2015 foreground maps— both anomalous microwave emission (AME) maps, free-free emission, synchrotron radiation and thermal dust emission. The weighting coefficients are constructed taking account of the signal-to-error ratio given by the data product. Positive correlation is found for AME compared with thermal dust emission as well as synchrotron radiation. We find AME and free-free emission tending to be anti-correlated, however, when investigating different scales, their relationship appears to be more complex. We argue that dust particles responsible for AME are pushed out of hot zones in the interstellar medium (ISM)

  17. Emission spectroscopy for coal-fired cyclone furnace diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Wehrmeyer, J.A.; Boll, D.E.; Smith, R. [Vanderbilt University, Nashville, TN (United States). Dept. of Mechanical Engineering

    2003-08-01

    Using a spectrograph and charge-coupled device (CCD) camera, ultraviolet and visible light emission spectra were obtained from a coal-burning electric utility's cyclone furnaces operating at either fuel-rich or fuel-lean conditions. The aim of this effort is to identify light emission signals that can be related to a cyclone furnace's operating condition in order to adjust its air/fuel ratio to minimize pollutant production. Emission spectra at the burner and outlet ends of cyclone furnaces were obtained. Spectra from all cyclone burners show emission lines for the trace elements Li, Na, K, and Rb, as well as the molecular species OH and CaOH. The Ca emission line is detected at the burner end of both the fuel-rich and fuellean cyclone furnaces but is not detected at the outlet ends of either furnace type. Along with the disappearance of Ca is a concomitant increase in the CaOH signal at the outlet end of both types of furnaces. The OH signal strength is in general stronger when viewing at the burner end rather than the exhaust end of both the fuel-rich and fuel-lean cyclone furnaces, probably due to high, non-equilibrium amounts of OH present inside the furnace. Only one molecular species was detected that could be used as a measure of air/fuel ratio: MgOH. It was detected at the burner end of fuel-rich cyclone furnaces but not detected in fuel-lean cyclone furnaces. More direct markers of air/fuel ratio, such as CO and 02 emission, were not detected, probably due to the generally weak nature of molecular emission relative to ambient blackbody emission present in the cyclone furnaces, even at ultraviolet wavelengths.

  18. Variations in the OM/OC ratio of urban organic aerosol next to a major roadway.

    Science.gov (United States)

    Brown, Steven G; Lee, Taehyoung; Roberts, Paul T; Collett, Jeffrey L

    2013-12-01

    Understanding the organic matter/organic carbon (OM/OC) ratio in ambient particulate matter (PM) is critical to achieve mass closure in routine PM measurements, to assess the sources of and the degree of chemical processing organic aerosol particles have undergone, and to relate ambient pollutant concentrations to health effects. Of particular interest is how the OM/OC ratio varies in the urban environment, where strong spatial and temporal gradients in source emissions are common. We provide results of near-roadway high-time-resolution PM1 OM concentration and OM/OC ratio observations during January 2008 at Fyfe Elementary School in Las Vegas, NV, 18 m from the U.S. 95 freeway soundwall, measured with an Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-AMS). The average OM/OC ratio was 1.54 (+/- 0.20 standard deviation), typical of environments with a low amount of secondary aerosol formation. The 2-min average OM/OC ratios varied between 1.17 and 2.67, and daily average OM/OC ratios varied between 1.44 and 1.73. The ratios were highest during periods of low OM concentrations and generally low during periods of high OM concentrations. OM/OC ratios were low (1.52 +/- 0.14, on average) during the morning rush hour (average OM = 2.4 microg/m3), when vehicular emissions dominate this near-road measurement site. The ratios were slightly lower (1.46 +/- 0.10) in the evening (average OM = 6.3 microg/m3), when a combination of vehicular and fresh residential biomass burning emissions was typically present during times with temperature inversions. The hourly averaged OM/OC ratio peaked at 1.66 at midday. OM concentrations were similar regardless of whether the monitoring site was downwind or upwind of the adjacent freeway throughout the day, though they were higher during stagnant conditions (wind speed < 0.5 m/sec). The OM/OC ratio generally varied more with time of day than with wind direction and speed.

  19. A study on emission characteristics of an EFI engine with ethanol blended gasoline fuels

    Science.gov (United States)

    He, Bang-Quan; Wang, Jian-Xin; Hao, Ji-Ming; Yan, Xiao-Guang; Xiao, Jian-Hua

    The effect of ethanol blended gasoline fuels on emissions and catalyst conversion efficiencies was investigated in a spark ignition engine with an electronic fuel injection (EFI) system. The addition of ethanol to gasoline fuel enhances the octane number of the blended fuels and changes distillation temperature. Ethanol can decrease engine-out regulated emissions. The fuel containing 30% ethanol by volume can drastically reduce engine-out total hydrocarbon emissions (THC) at operating conditions and engine-out THC, CO and NO x emissions at idle speed, but unburned ethanol and acetaldehyde emissions increase. Pt/Rh based three-way catalysts are effective in reducing acetaldehyde emissions, but the conversion of unburned ethanol is low. Tailpipe emissions of THC, CO and NO x have close relation to engine-out emissions, catalyst conversion efficiency, engine's speed and load, air/fuel equivalence ratio. Moreover, the blended fuels can decrease brake specific energy consumption.

  20. Computations of NOx emissions of domestic boilers

    Energy Technology Data Exchange (ETDEWEB)

    Thevenin, D. [Ecole Centrale de Paris, 92 - Chatenay-Malabry (France). EM2C Lab.; Gicquel, O.; Darabiha, N.

    2001-07-01

    Due to severe regulations concerning pollutant emissions, practical devices using combustion to release energy must be designed from the start using accurate, predictive numerical tools. A partially premixed methane/air flame in a two-dimensional configuration is investigated in this work. This configuration is close to those used in real domestic gas boilers. The flame structure and flow pattern are calculated using complex chemistry and detailed transport models. A post-processing method is then used to predict NO emission. Computations are performed for two configurations. The two cases have the same primary and secondary mass flow-rates and equivalence ratio. The only difference between them is the introduction of an insert inside the primary injector. Both results have been compared to measurements. Calculations are found to be in good agreement with the flame shapes observed experimentally. The classical burner shows a Bunsen-type flame while the one with an insert has a totally different shape (butterfly-type flame). NO emission levels are also well predicted in both configurations. The butterfly flame induces a reduction in NO emission. This reduction seems to be due to the increased mixing between the burnt gases and the secondary air jet, which homogenizes the temperature distribution and reduces the maximum temperature. (orig.)

  1. Alternate-Fueled Combustor-Sector Emissions

    Science.gov (United States)

    Saxena, Nikita T.; Thomas, Anna E.; Shouse, Dale T.; Neuroth, Craig; Hendricks, Robert C.; Lynch, Amy; Frayne, Charles W.; Stutrud, Jeffrey S.; Corporan, Edwin; Hankins, Terry

    2013-01-01

    In order to meet rapidly growing demand for fuel, as well as address environmental concerns, the aviation industry has been testing alternate fuels for performance and technical usability in commercial and military aircraft. In order to make alternate fuels (and blends) a viable option for aviation, the fuel must be able to perform at a similar or higher level than traditional petroleum fuel. They also attempt to curb harmful emissions, and therefore a truly effective alternate fuel would emit at or under the level of currently used fuel. This report analyzes data from gaseous and particulate emissions of an aircraft combustor sector. The data were evaluated at various inlet conditions, including variation in pressure and temperature, fuel-to-air ratios, and percent composition of alternate fuel. Traditional JP-8+100 data were taken as a baseline, and blends of JP-8+100 with synthetic-paraffinic-kerosene (SPK) fuel (Fischer-Tropsch (FT)) were used for comparison. Gaseous and particulate emissions, as well as flame luminosity, were assessed for differences between FT composition of 0, 50, and 100 percent. The data show that SPK fuel (an FT-derived fuel) had slightly lower harmful gaseous emissions, and smoke number information corroborated the hypothesis that SPK-FT fuels are cleaner burning fuels.

  2. Towards Verifying National CO2 Emissions

    Science.gov (United States)

    Fung, I. Y.; Wuerth, S. M.; Anderson, J. L.

    2017-12-01

    With the Paris Agreement, nations around the world have pledged their voluntary reductions in future CO2 emissions. Satellite observations of atmospheric CO2 have the potential to verify self-reported emission statistics around the globe. We present a carbon-weather data assimilation system, wherein raw weather observations together with satellite observations of the mixing ratio of column CO2 from the Orbiting Carbon Observatory-2 are assimilated every 6 hours into the NCAR carbon-climate model CAM5 coupled to the Ensemble Kalman Filter of DART. In an OSSE, we reduced the fossil fuel emissions from a country, and estimated the emissions innovations demanded by the atmospheric CO2 observations. The uncertainties in the innovation are analyzed with respect to the uncertainties in the meteorology to determine the significance of the result. The work follows from "On the use of incomplete historical data to infer the present state of the atmosphere" (Charney et al. 1969), which maps the path for continuous data assimilation for weather forecasting and the five decades of progress since.

  3. D/H ratio for Jupiter

    International Nuclear Information System (INIS)

    Smith, H.; Schempp, W.V.; Baines, K.H.

    1989-01-01

    Observations of Jupiter's spectrum near the R5(0) HD line at 6063.88 A are reported. A feature with an equivalent width of 0.065 + or - 0.021 mA is coincident with the expected line. This feature is compared with HD profiles computed for inhomogeneous scattering models for Jupiter to yield a range for the Jovian D/H ratio of 1.0-2.9 x 10 to the -5th. This D/H ratio is in the lower range of previously reported D/H values for Jupiter and corresponds to an essentially solar D/H ratio for Jupiter. The detection of HD features in the presence of probable blends with spectral features of minor atmospheric hydrocarbon molecules is discussed. Such blends may make unambiguous identification of HD features difficult. 26 references

  4. Odor concentration invariance by chemical ratio coding

    Directory of Open Access Journals (Sweden)

    Naoshige Uchida

    2008-08-01

    Full Text Available Many animal species rely on chemical signals to extract ecologically important information from the environment. Yet in natural conditions chemical signals will frequently undergo concentration changes that produce differences in both level and pattern of activation of olfactory receptor neurons. Thus, a central problem in olfactory processing is how the system is able to recognize the same stimulus across different concentrations. To signal species identity for mate recognition, some insects use the ratio of two components in a binary chemical mixture to produce a code that is invariant to dilution. Here, using psychophysical methods, we show that rats also classify binary odor mixtures according to the molar ratios of their components, spontaneously generalizing over at least a tenfold concentration range. These results indicate that extracting chemical ratio information is not restricted to pheromone signaling and suggest a general solution for concentration-invariant odor recognition by the mammalian olfactory system.

  5. Isotope ratio in stellar atmospheres and nucleosynthesis

    International Nuclear Information System (INIS)

    Barbuy, B.L.S.

    1987-01-01

    The determination of isotopic ratios in stellar atmospheres is studied. The isotopic shift of atomic and molecular lines of different species of a certain element is examined. CH and MgH lines are observed in order to obtain the 12 C: 13 C and 24 Mg: 25 Mg: 26 Mg isotpic ratios. The formation of lines in stellar atmospheres is computed and the resulting synthetic spectra are employed to determine the isotopic abundances. The results obtained for the isotopic ratios are compared to predictions of nucleosynthesis theories. Finally, the concept of primary and secondary element is discussed, and these definitions are applied to the observed variations in the abundance of elements as a function of metallicity. (author) [pt

  6. Transport in a small aspect ratio torus

    International Nuclear Information System (INIS)

    White, R.B.; Gates, D.A.; Mynick, H.E.

    2005-01-01

    Transport theory in toroidal devices often assumes large aspect ratio and also assumes the poloidal field is small compared to the toroidal field. These assumptions result in transport which in the low collision rate limit is dominated by banana orbits, giving the largest collisionless excursion of a particle from an initial flux surface. However in a small aspect ratio device the gyro radius may be larger than the banana excursion, resulting in significant deviations from the standard neoclassical predictions. In this paper we report numerical simulation of diffusion in low and high beta low aspect ratio equilibria. We also sketch an analytic theory. The diffusion, which we refer to as omniclassical, is a combination of neoclassical and properly averaged classical effects, and can be two or three times the neoclassical value. Good agreement of the analytic theory with numerical simulations is obtained. (author)

  7. The FAOSTAT database of greenhouse gas emissions from agriculture

    International Nuclear Information System (INIS)

    Tubiello, Francesco N; Salvatore, Mirella; Rossi, Simone; Ferrara, Alessandro; Fitton, Nuala; Smith, Pete

    2013-01-01

    2000–2010, the ratio of agriculture to fossil fuel emissions has decreased, from 17.2% to 13.7%, and the decrease is even greater for the ratio of net deforestation to fossil fuel emissions: from 19.1% to 10.1%. In fact, in the year 2000, emissions from agriculture have been consistently larger—about 1.2 Gt CO 2 yr −1 in 2010—than those from net deforestation. (letter)

  8. Numerical investigation of exhaust gas emissions for a dual fuel engine configuration using diesel and pongamia oil.

    Science.gov (United States)

    Mohamed Ibrahim, N H; Udayakumar, M

    2016-12-01

    The investigation presented in this paper focuses on determination of gaseous exhaust emissions by computational simulation during combustion in compression ignition engine with pongamia oil substitution. Combustion is modeled using Equilibrium Constants Method (ECM) with MATLAB program to calculate the mole fraction of 10 combustion products when pongamia oil is burnt along with diesel at variable equivalence ratio and blend ratio. It had been observed that pongamia oil substitution causes decrease in the CO emission and increase in the NO x emission as the blend ratio as well as equivalence ratio increases. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. The reaction index and positivity ratio revisited

    DEFF Research Database (Denmark)

    Andersen, Klaus Ejner; Andersen, Flemming

    2008-01-01

    BACKGROUND AND OBJECTIVES: Assessing the quality of patch test preparations continues to be a challenge. 2 parameters, the reaction index (RI) and positivity ratio (PR), have been proposed as quality indicators by the Information Network of Departments of Dermatology (IVDK). The value of these st......BACKGROUND AND OBJECTIVES: Assessing the quality of patch test preparations continues to be a challenge. 2 parameters, the reaction index (RI) and positivity ratio (PR), have been proposed as quality indicators by the Information Network of Departments of Dermatology (IVDK). The value...

  10. Uranium isotope ratio measurements in field settings

    International Nuclear Information System (INIS)

    Shaw, R.W.; Barshick, C.M.; Young, J.P.; Ramsey, J.M.

    1997-01-01

    The authors have developed a technique for uranium isotope ratio measurements of powder samples in field settings. Such a method will be invaluable for environmental studies, radioactive waste operations, and decommissioning and decontamination operations. Immediate field data can help guide an ongoing sampling campaign. The measurement encompasses glow discharge sputtering from pressed sample hollow cathodes, high resolution laser spectroscopy using conveniently tunable diode lasers, and optogalvanic detection. At 10% 235 U enrichment and above, the measurement precision for 235 U/( 235 U+ 238 U) isotope ratios was ±3%; it declined to ±15% for 0.3% (i.e., depleted) samples. A prototype instrument was constructed and is described

  11. Ultima Ratio as a Constitutional Principle

    Directory of Open Access Journals (Sweden)

    Kaarlo Tuori

    2013-01-01

    Full Text Available The paper argues the criminal law notion of ultima ratio is an instance of a broader constitutional law principle of proportionality. However, ultima ratio is not the only principle relevant in a constitutional assessment of criminalization. The role of ultima ratio is to impose limitations on criminalization. But constitutional doctrines also exist which call for criminalization and might even be seen as establishing a criminalization obligation. The paper examines three constitutional counter weights to ultima ratio. The first of these is discussed in the context of state constitutions. This is the cluster of the interrelated constitutional doctrines of the horizontal effect of fundamental rights and the protective duty of the state, as well as the understanding of collective security as a basic right. These doctrines are analysed in the light of the praxis of the German Constitutional Court and the Finnish Constitutional Law Committee. The two other constitutional counterweights are discussed at the level of the transnational, European constitution. These are the principles of precaution and effectiveness. Este artículo defiende que el concepto de ultima ratio es una instancia más amplia del principio de proporcionalidad dentro del derecho constitucional. Sin embargo, el ultima ratio no es el único principio relevante en la valoración constitucional de la criminalización. El papel del ultima ratio es imponer límites a la criminalización. Pero también existen doctrinas constitucionales que exigen la criminalización e incluso dan pie a entender que obligan a establecer una pena. El documento examina tres contrapesos constitucionales al ultima ratio. En primer lugar, se analiza en el contexto de las constituciones estatales. Este es el conjunto de las doctrinas constitucionales interrelacionadas entre el efecto horizontal de los derechos fundamentales y el deber de protección del Estado, así como la asunción de la seguridad colectiva

  12. Radioactive anomaly discrimination from spectral ratios

    Science.gov (United States)

    Maniscalco, James; Sjoden, Glenn; Chapman, Mac Clements

    2013-08-20

    A method for discriminating a radioactive anomaly from naturally occurring radioactive materials includes detecting a first number of gamma photons having energies in a first range of energy values within a predetermined period of time and detecting a second number of gamma photons having energies in a second range of energy values within the predetermined period of time. The method further includes determining, in a controller, a ratio of the first number of gamma photons having energies in the first range and the second number of gamma photons having energies in the second range, and determining that a radioactive anomaly is present when the ratio exceeds a threshold value.

  13. Emission control by cyclone combustor technology

    Energy Technology Data Exchange (ETDEWEB)

    Syred, N; Styles, A C; Sahatimehr, A

    1983-09-01

    Recent work carried out on a multi-inlet gas-fired cyclone combustor has shown that NO formation is reduced to negligible proportions when operated at mixture ratios 1.5 < PHI < 2.2 with combustion occurring under fully premixed fuel conditions. Elimination of hot spots, common to partial premixed systems, has been achieved with mean temperatures below 1300 C, thereby reducing NO emissions (1.5 ppm) by preventing the onset of Zeldovich and prompt mechanisms. The low NO levels are therefore dependent on a combination of low flame front temperature (about 1100 C) and premixed combustion conditions. Owing to the operating mode of combustion, heat transfer at the walls plays an important role in flame stability. Insulation of the cyclone chamber by refractory has been found to extend the operating range to higher mixture ratios. Conversely, it is expected that heat removal from the walls would enable the combustor to operate at mixture ratios nearer to stoichiometric, whilst still giving rise to low levels of NO emission. 17 references.

  14. Alvar engine. An engine with variable compression ratio. Experiments and tests

    Energy Technology Data Exchange (ETDEWEB)

    Erlandsson, Olof

    1998-09-01

    This report is focused on tests with Variable Compression Ratio (VCR) engines, according to the Alvar engine principle. Variable compression ratio means an engine design where it is possible to change the nominal compression ratio. The purpose is to increase the fuel efficiency at part load by increasing the compression ratio. At maximum load, and maybe supercharging with for example turbocharger, it is not possible to keep a high compression ratio because of the knock phenomena. Knock is a shock wave caused by self-ignition of the fuel-air mix. If knock occurs, the engine will be exposed to a destructive load. Because of the reasons mentioned it would be an advantage if it would be possible to change the compression ratio continuously when the load changes. The Alvar engine provides a solution for variable compression ratio based on well-known engine components. This paper provides information about efficiency and emission characteristics from tests with two Alvar engines. Results from tests with a phase shift mechanism (for automatic compression ratio control) for the Alvar engine are also reviewed Examination paper. 5 refs, 23 figs, 2 tabs, 5 appendices

  15. [Measurement model of carbon emission from forest fire: a review].

    Science.gov (United States)

    Hu, Hai-Qing; Wei, Shu-Jing; Jin, Sen; Sun, Long

    2012-05-01

    Forest fire is the main disturbance factor for forest ecosystem, and an important pathway of the decrease of vegetation- and soil carbon storage. Large amount of carbonaceous gases in forest fire can release into atmosphere, giving remarkable impacts on the atmospheric carbon balance and global climate change. To scientifically and effectively measure the carbonaceous gases emission from forest fire is of importance in understanding the significance of forest fire in the carbon balance and climate change. This paper reviewed the research progress in the measurement model of carbon emission from forest fire, which covered three critical issues, i. e., measurement methods of forest fire-induced total carbon emission and carbonaceous gases emission, affecting factors and measurement parameters of measurement model, and cause analysis of the uncertainty in the measurement of the carbon emissions. Three path selections to improve the quantitative measurement of the carbon emissions were proposed, i. e., using high resolution remote sensing data and improving algorithm and estimation accuracy of burned area in combining with effective fuel measurement model to improve the accuracy of the estimated fuel load, using high resolution remote sensing images combined with indoor controlled environment experiments, field measurements, and field ground surveys to determine the combustion efficiency, and combining indoor controlled environment experiments with field air sampling to determine the emission factors and emission ratio.

  16. Emission computed tomography

    International Nuclear Information System (INIS)

    Budinger, T.F.; Gullberg, G.T.; Huesman, R.H.

    1979-01-01

    This chapter is devoted to the methods of computer assisted tomography for determination of the three-dimensional distribution of gamma-emitting radionuclides in the human body. The major applications of emission computed tomography are in biological research and medical diagnostic procedures. The objectives of these procedures are to make quantitative measurements of in vivo biochemical and hemodynamic functions

  17. Emissions - problems and benefits

    International Nuclear Information System (INIS)

    Rossi, C.; Hurd, P.J.

    1992-01-01

    Air pollution due to emissions arising from the use of biomass in electricity generation is discussed. One of the most attractive aspects of the use of biomass is that there is no net increase of carbon dioxide in the atmosphere. During growth biomass absorbs CO 2 ; during combustion, either directly or as biomass derived fuels, it releases CO 2 , making a closed cycle. Another benefit from the use of biomass is its typically very low sulphur content and the consequent low sulphur oxide emissions from biomass-fired generation plants. Biomass is, however, less satisfactory in relation to nitrogen oxides (NO x ). Control of the nitrogen content of the biomass feedstock, advanced high technology combustion techniques and some post-engine treatment may all be necessary to comply with the legal limits for NO x emissions. The low ash content of biomass, particularly biomass derived oils, makes it possible to limit particulate emission to very low levels. It will be important, though, to bear in mind the need to limit the sodium and potassium content to below 1 ppm by mass in bio-oil to be used in a high temperature gas turbine. Levels of micropollutants will be low if the chlorine content of biomass feedstock is low. However, residence times at peak temperature in typical gas turbines combustors are too short to destroy some micropollutants. (UK)

  18. Positron emission tomography

    International Nuclear Information System (INIS)

    Pavuk, M.

    2003-12-01

    The aim of this project is to provide a simple summary of new trends in positron emission tomography and its basic physical principles. It provides thereby compendious introduction of the trends of the present development in diagnostics using PET systems. A review of available literature was performed. (author)

  19. Evoked acoustic emission

    DEFF Research Database (Denmark)

    Elberling, C; Parbo, J; Johnsen, N J

    1985-01-01

    Stimulated acoustic emissions were recorded in response to tonal stimuli at 60 dB p.e. SPL in a small group of normal-hearing adults. Power spectral analysis reveals that the evoked activity from each ear contains energy in preferential frequency bands and the change of stimulus frequency has only...

  20. Positron emission tomography

    NARCIS (Netherlands)

    Paans, AMJ

    Positron Emission Tomography (PET) is a method for determining biochemical and physiological processes in vivo in a quantitative way by using radiopharmaceuticals labelled with positron emitting radionuclides as C-11, N-13, O-15 and F-18 and by measuring the annihilation radiation using a